diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@alloca.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@alloca.h
new file mode 100644
index 0000000000000000000000000000000000000000..7665a131a63d10db68a38a97a96dd1e04a482e27
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@alloca.h
@@ -0,0 +1,40 @@
+/* Copyright (C) 1992-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef	_ALLOCA_H
+#define	_ALLOCA_H	1
+
+#include <features.h>
+
+#define	__need_size_t
+#include <stddef.h>
+
+__BEGIN_DECLS
+
+/* Remove any previous definition.  */
+#undef	alloca
+
+/* Allocate a block that will be freed when the calling function exits.  */
+extern void *alloca (size_t __size) __THROW;
+
+#ifdef	__GNUC__
+# define alloca(size)	__builtin_alloca (size)
+#endif /* GCC.  */
+
+__END_DECLS
+
+#endif /* alloca.h */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@alloca.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@alloca.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@assert.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@assert.h
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index 0000000000000000000000000000000000000000..67f1cce5e994c013d01d9102ea488f76d66b96ca
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@assert.h
@@ -0,0 +1,141 @@
+/* Copyright (C) 1991-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+/*
+ *	ISO C99 Standard: 7.2 Diagnostics	<assert.h>
+ */
+
+#ifdef	_ASSERT_H
+
+# undef	_ASSERT_H
+# undef	assert
+# undef __ASSERT_VOID_CAST
+
+# ifdef	__USE_GNU
+#  undef assert_perror
+# endif
+
+#endif /* assert.h	*/
+
+#define	_ASSERT_H	1
+#include <features.h>
+
+#if defined __cplusplus && __GNUC_PREREQ (2,95)
+# define __ASSERT_VOID_CAST static_cast<void>
+#else
+# define __ASSERT_VOID_CAST (void)
+#endif
+
+/* void assert (int expression);
+
+   If NDEBUG is defined, do nothing.
+   If not, and EXPRESSION is zero, print an error message and abort.  */
+
+#ifdef	NDEBUG
+
+# define assert(expr)		(__ASSERT_VOID_CAST (0))
+
+/* void assert_perror (int errnum);
+
+   If NDEBUG is defined, do nothing.  If not, and ERRNUM is not zero, print an
+   error message with the error text for ERRNUM and abort.
+   (This is a GNU extension.) */
+
+# ifdef	__USE_GNU
+#  define assert_perror(errnum)	(__ASSERT_VOID_CAST (0))
+# endif
+
+#else /* Not NDEBUG.  */
+
+__BEGIN_DECLS
+
+/* This prints an "Assertion failed" message and aborts.  */
+extern void __assert_fail (const char *__assertion, const char *__file,
+			   unsigned int __line, const char *__function)
+     __THROW __attribute__ ((__noreturn__));
+
+/* Likewise, but prints the error text for ERRNUM.  */
+extern void __assert_perror_fail (int __errnum, const char *__file,
+				  unsigned int __line, const char *__function)
+     __THROW __attribute__ ((__noreturn__));
+
+
+/* The following is not at all used here but needed for standard
+   compliance.  */
+extern void __assert (const char *__assertion, const char *__file, int __line)
+     __THROW __attribute__ ((__noreturn__));
+
+
+__END_DECLS
+
+/* When possible, define assert so that it does not add extra
+   parentheses around EXPR.  Otherwise, those added parentheses would
+   suppress warnings we'd expect to be detected by gcc's -Wparentheses.  */
+# if defined __cplusplus
+#  define assert(expr)							\
+     (static_cast <bool> (expr)						\
+      ? void (0)							\
+      : __assert_fail (#expr, __FILE__, __LINE__, __ASSERT_FUNCTION))
+# elif !defined __GNUC__ || defined __STRICT_ANSI__
+#  define assert(expr)							\
+    ((expr)								\
+     ? __ASSERT_VOID_CAST (0)						\
+     : __assert_fail (#expr, __FILE__, __LINE__, __ASSERT_FUNCTION))
+# else
+/* The first occurrence of EXPR is not evaluated due to the sizeof,
+   but will trigger any pedantic warnings masked by the __extension__
+   for the second occurrence.  The ternary operator is required to
+   support function pointers and bit fields in this context, and to
+   suppress the evaluation of variable length arrays.  */
+#  define assert(expr)							\
+  ((void) sizeof ((expr) ? 1 : 0), __extension__ ({			\
+      if (expr)								\
+        ; /* empty */							\
+      else								\
+        __assert_fail (#expr, __FILE__, __LINE__, __ASSERT_FUNCTION);	\
+    }))
+# endif
+
+# ifdef	__USE_GNU
+#  define assert_perror(errnum)						\
+  (!(errnum)								\
+   ? __ASSERT_VOID_CAST (0)						\
+   : __assert_perror_fail ((errnum), __FILE__, __LINE__, __ASSERT_FUNCTION))
+# endif
+
+/* Version 2.4 and later of GCC define a magical variable `__PRETTY_FUNCTION__'
+   which contains the name of the function currently being defined.
+   This is broken in G++ before version 2.6.
+   C9x has a similar variable called __func__, but prefer the GCC one since
+   it demangles C++ function names.  */
+# if defined __cplusplus ? __GNUC_PREREQ (2, 6) : __GNUC_PREREQ (2, 4)
+#   define __ASSERT_FUNCTION	__extension__ __PRETTY_FUNCTION__
+# else
+#  if defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L
+#   define __ASSERT_FUNCTION	__func__
+#  else
+#   define __ASSERT_FUNCTION	((const char *) 0)
+#  endif
+# endif
+
+#endif /* NDEBUG.  */
+
+
+#if defined __USE_ISOC11 && !defined __cplusplus
+# undef static_assert
+# define static_assert _Static_assert
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@assert.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@assert.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@atomic_wide_counter.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@atomic_wide_counter.h
new file mode 100644
index 0000000000000000000000000000000000000000..e0f80386529e4f5481dd8f357870bf502ab0c15e
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@atomic_wide_counter.h
@@ -0,0 +1,35 @@
+/* Monotonically increasing wide counters (at least 62 bits).
+   Copyright (C) 2016-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _BITS_ATOMIC_WIDE_COUNTER_H
+#define _BITS_ATOMIC_WIDE_COUNTER_H
+
+/* Counter that is monotonically increasing (by less than 2**31 per
+   increment), with a single writer, and an arbitrary number of
+   readers.  */
+typedef union
+{
+  __extension__ unsigned long long int __value64;
+  struct
+  {
+    unsigned int __low;
+    unsigned int __high;
+  } __value32;
+} __atomic_wide_counter;
+
+#endif /* _BITS_ATOMIC_WIDE_COUNTER_H */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@atomic_wide_counter.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@atomic_wide_counter.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@byteswap.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@byteswap.h
new file mode 100644
index 0000000000000000000000000000000000000000..ca8417d59a80d3db8ac00a866b76cb3cd98a97f0
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@byteswap.h
@@ -0,0 +1,79 @@
+/* Macros and inline functions to swap the order of bytes in integer values.
+   Copyright (C) 1997-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#if !defined _BYTESWAP_H && !defined _NETINET_IN_H && !defined _ENDIAN_H
+# error "Never use <bits/byteswap.h> directly; include <byteswap.h> instead."
+#endif
+
+#ifndef _BITS_BYTESWAP_H
+#define _BITS_BYTESWAP_H 1
+
+#include <features.h>
+#include <bits/types.h>
+
+/* Swap bytes in 16-bit value.  */
+#define __bswap_constant_16(x)					\
+  ((__uint16_t) ((((x) >> 8) & 0xff) | (((x) & 0xff) << 8)))
+
+static __inline __uint16_t
+__bswap_16 (__uint16_t __bsx)
+{
+#if __GNUC_PREREQ (4, 8)
+  return __builtin_bswap16 (__bsx);
+#else
+  return __bswap_constant_16 (__bsx);
+#endif
+}
+
+/* Swap bytes in 32-bit value.  */
+#define __bswap_constant_32(x)					\
+  ((((x) & 0xff000000u) >> 24) | (((x) & 0x00ff0000u) >> 8)	\
+   | (((x) & 0x0000ff00u) << 8) | (((x) & 0x000000ffu) << 24))
+
+static __inline __uint32_t
+__bswap_32 (__uint32_t __bsx)
+{
+#if __GNUC_PREREQ (4, 3)
+  return __builtin_bswap32 (__bsx);
+#else
+  return __bswap_constant_32 (__bsx);
+#endif
+}
+
+/* Swap bytes in 64-bit value.  */
+#define __bswap_constant_64(x)			\
+  ((((x) & 0xff00000000000000ull) >> 56)	\
+   | (((x) & 0x00ff000000000000ull) >> 40)	\
+   | (((x) & 0x0000ff0000000000ull) >> 24)	\
+   | (((x) & 0x000000ff00000000ull) >> 8)	\
+   | (((x) & 0x00000000ff000000ull) << 8)	\
+   | (((x) & 0x0000000000ff0000ull) << 24)	\
+   | (((x) & 0x000000000000ff00ull) << 40)	\
+   | (((x) & 0x00000000000000ffull) << 56))
+
+__extension__ static __inline __uint64_t
+__bswap_64 (__uint64_t __bsx)
+{
+#if __GNUC_PREREQ (4, 3)
+  return __builtin_bswap64 (__bsx);
+#else
+  return __bswap_constant_64 (__bsx);
+#endif
+}
+
+#endif /* _BITS_BYTESWAP_H */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@byteswap.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@byteswap.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@confname.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@confname.h
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index 0000000000000000000000000000000000000000..f8ae1e49bbb237e3df9276968ff605f1ea18a0b0
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@confname.h
@@ -0,0 +1,681 @@
+/* `sysconf', `pathconf', and `confstr' NAME values.  Generic version.
+   Copyright (C) 1993-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _UNISTD_H
+# error "Never use <bits/confname.h> directly; include <unistd.h> instead."
+#endif
+
+/* Values for the NAME argument to `pathconf' and `fpathconf'.  */
+enum
+  {
+    _PC_LINK_MAX,
+#define	_PC_LINK_MAX			_PC_LINK_MAX
+    _PC_MAX_CANON,
+#define	_PC_MAX_CANON			_PC_MAX_CANON
+    _PC_MAX_INPUT,
+#define	_PC_MAX_INPUT			_PC_MAX_INPUT
+    _PC_NAME_MAX,
+#define	_PC_NAME_MAX			_PC_NAME_MAX
+    _PC_PATH_MAX,
+#define	_PC_PATH_MAX			_PC_PATH_MAX
+    _PC_PIPE_BUF,
+#define	_PC_PIPE_BUF			_PC_PIPE_BUF
+    _PC_CHOWN_RESTRICTED,
+#define	_PC_CHOWN_RESTRICTED		_PC_CHOWN_RESTRICTED
+    _PC_NO_TRUNC,
+#define	_PC_NO_TRUNC			_PC_NO_TRUNC
+    _PC_VDISABLE,
+#define _PC_VDISABLE			_PC_VDISABLE
+    _PC_SYNC_IO,
+#define	_PC_SYNC_IO			_PC_SYNC_IO
+    _PC_ASYNC_IO,
+#define	_PC_ASYNC_IO			_PC_ASYNC_IO
+    _PC_PRIO_IO,
+#define	_PC_PRIO_IO			_PC_PRIO_IO
+    _PC_SOCK_MAXBUF,
+#define	_PC_SOCK_MAXBUF			_PC_SOCK_MAXBUF
+    _PC_FILESIZEBITS,
+#define _PC_FILESIZEBITS		_PC_FILESIZEBITS
+    _PC_REC_INCR_XFER_SIZE,
+#define _PC_REC_INCR_XFER_SIZE		_PC_REC_INCR_XFER_SIZE
+    _PC_REC_MAX_XFER_SIZE,
+#define _PC_REC_MAX_XFER_SIZE		_PC_REC_MAX_XFER_SIZE
+    _PC_REC_MIN_XFER_SIZE,
+#define _PC_REC_MIN_XFER_SIZE		_PC_REC_MIN_XFER_SIZE
+    _PC_REC_XFER_ALIGN,
+#define _PC_REC_XFER_ALIGN		_PC_REC_XFER_ALIGN
+    _PC_ALLOC_SIZE_MIN,
+#define _PC_ALLOC_SIZE_MIN		_PC_ALLOC_SIZE_MIN
+    _PC_SYMLINK_MAX,
+#define _PC_SYMLINK_MAX			_PC_SYMLINK_MAX
+    _PC_2_SYMLINKS
+#define _PC_2_SYMLINKS			_PC_2_SYMLINKS
+  };
+
+/* Values for the argument to `sysconf'.  */
+enum
+  {
+    _SC_ARG_MAX,
+#define	_SC_ARG_MAX			_SC_ARG_MAX
+    _SC_CHILD_MAX,
+#define	_SC_CHILD_MAX			_SC_CHILD_MAX
+    _SC_CLK_TCK,
+#define	_SC_CLK_TCK			_SC_CLK_TCK
+    _SC_NGROUPS_MAX,
+#define	_SC_NGROUPS_MAX			_SC_NGROUPS_MAX
+    _SC_OPEN_MAX,
+#define	_SC_OPEN_MAX			_SC_OPEN_MAX
+    _SC_STREAM_MAX,
+#define	_SC_STREAM_MAX			_SC_STREAM_MAX
+    _SC_TZNAME_MAX,
+#define	_SC_TZNAME_MAX			_SC_TZNAME_MAX
+    _SC_JOB_CONTROL,
+#define	_SC_JOB_CONTROL			_SC_JOB_CONTROL
+    _SC_SAVED_IDS,
+#define	_SC_SAVED_IDS			_SC_SAVED_IDS
+    _SC_REALTIME_SIGNALS,
+#define	_SC_REALTIME_SIGNALS		_SC_REALTIME_SIGNALS
+    _SC_PRIORITY_SCHEDULING,
+#define	_SC_PRIORITY_SCHEDULING		_SC_PRIORITY_SCHEDULING
+    _SC_TIMERS,
+#define	_SC_TIMERS			_SC_TIMERS
+    _SC_ASYNCHRONOUS_IO,
+#define	_SC_ASYNCHRONOUS_IO		_SC_ASYNCHRONOUS_IO
+    _SC_PRIORITIZED_IO,
+#define	_SC_PRIORITIZED_IO		_SC_PRIORITIZED_IO
+    _SC_SYNCHRONIZED_IO,
+#define	_SC_SYNCHRONIZED_IO		_SC_SYNCHRONIZED_IO
+    _SC_FSYNC,
+#define	_SC_FSYNC			_SC_FSYNC
+    _SC_MAPPED_FILES,
+#define	_SC_MAPPED_FILES		_SC_MAPPED_FILES
+    _SC_MEMLOCK,
+#define	_SC_MEMLOCK			_SC_MEMLOCK
+    _SC_MEMLOCK_RANGE,
+#define	_SC_MEMLOCK_RANGE		_SC_MEMLOCK_RANGE
+    _SC_MEMORY_PROTECTION,
+#define	_SC_MEMORY_PROTECTION		_SC_MEMORY_PROTECTION
+    _SC_MESSAGE_PASSING,
+#define	_SC_MESSAGE_PASSING		_SC_MESSAGE_PASSING
+    _SC_SEMAPHORES,
+#define	_SC_SEMAPHORES			_SC_SEMAPHORES
+    _SC_SHARED_MEMORY_OBJECTS,
+#define	_SC_SHARED_MEMORY_OBJECTS	_SC_SHARED_MEMORY_OBJECTS
+    _SC_AIO_LISTIO_MAX,
+#define	_SC_AIO_LISTIO_MAX		_SC_AIO_LISTIO_MAX
+    _SC_AIO_MAX,
+#define	_SC_AIO_MAX			_SC_AIO_MAX
+    _SC_AIO_PRIO_DELTA_MAX,
+#define	_SC_AIO_PRIO_DELTA_MAX		_SC_AIO_PRIO_DELTA_MAX
+    _SC_DELAYTIMER_MAX,
+#define	_SC_DELAYTIMER_MAX		_SC_DELAYTIMER_MAX
+    _SC_MQ_OPEN_MAX,
+#define	_SC_MQ_OPEN_MAX			_SC_MQ_OPEN_MAX
+    _SC_MQ_PRIO_MAX,
+#define	_SC_MQ_PRIO_MAX			_SC_MQ_PRIO_MAX
+    _SC_VERSION,
+#define	_SC_VERSION			_SC_VERSION
+    _SC_PAGESIZE,
+#define	_SC_PAGESIZE			_SC_PAGESIZE
+#define	_SC_PAGE_SIZE			_SC_PAGESIZE
+    _SC_RTSIG_MAX,
+#define	_SC_RTSIG_MAX			_SC_RTSIG_MAX
+    _SC_SEM_NSEMS_MAX,
+#define	_SC_SEM_NSEMS_MAX		_SC_SEM_NSEMS_MAX
+    _SC_SEM_VALUE_MAX,
+#define	_SC_SEM_VALUE_MAX		_SC_SEM_VALUE_MAX
+    _SC_SIGQUEUE_MAX,
+#define	_SC_SIGQUEUE_MAX		_SC_SIGQUEUE_MAX
+    _SC_TIMER_MAX,
+#define	_SC_TIMER_MAX			_SC_TIMER_MAX
+
+    /* Values for the argument to `sysconf'
+       corresponding to _POSIX2_* symbols.  */
+    _SC_BC_BASE_MAX,
+#define	_SC_BC_BASE_MAX			_SC_BC_BASE_MAX
+    _SC_BC_DIM_MAX,
+#define	_SC_BC_DIM_MAX			_SC_BC_DIM_MAX
+    _SC_BC_SCALE_MAX,
+#define	_SC_BC_SCALE_MAX		_SC_BC_SCALE_MAX
+    _SC_BC_STRING_MAX,
+#define	_SC_BC_STRING_MAX		_SC_BC_STRING_MAX
+    _SC_COLL_WEIGHTS_MAX,
+#define	_SC_COLL_WEIGHTS_MAX		_SC_COLL_WEIGHTS_MAX
+    _SC_EQUIV_CLASS_MAX,
+#define	_SC_EQUIV_CLASS_MAX		_SC_EQUIV_CLASS_MAX
+    _SC_EXPR_NEST_MAX,
+#define	_SC_EXPR_NEST_MAX		_SC_EXPR_NEST_MAX
+    _SC_LINE_MAX,
+#define	_SC_LINE_MAX			_SC_LINE_MAX
+    _SC_RE_DUP_MAX,
+#define	_SC_RE_DUP_MAX			_SC_RE_DUP_MAX
+    _SC_CHARCLASS_NAME_MAX,
+#define	_SC_CHARCLASS_NAME_MAX		_SC_CHARCLASS_NAME_MAX
+
+    _SC_2_VERSION,
+#define	_SC_2_VERSION			_SC_2_VERSION
+    _SC_2_C_BIND,
+#define	_SC_2_C_BIND			_SC_2_C_BIND
+    _SC_2_C_DEV,
+#define	_SC_2_C_DEV			_SC_2_C_DEV
+    _SC_2_FORT_DEV,
+#define	_SC_2_FORT_DEV			_SC_2_FORT_DEV
+    _SC_2_FORT_RUN,
+#define	_SC_2_FORT_RUN			_SC_2_FORT_RUN
+    _SC_2_SW_DEV,
+#define	_SC_2_SW_DEV			_SC_2_SW_DEV
+    _SC_2_LOCALEDEF,
+#define	_SC_2_LOCALEDEF			_SC_2_LOCALEDEF
+
+    _SC_PII,
+#define	_SC_PII				_SC_PII
+    _SC_PII_XTI,
+#define	_SC_PII_XTI			_SC_PII_XTI
+    _SC_PII_SOCKET,
+#define	_SC_PII_SOCKET			_SC_PII_SOCKET
+    _SC_PII_INTERNET,
+#define	_SC_PII_INTERNET		_SC_PII_INTERNET
+    _SC_PII_OSI,
+#define	_SC_PII_OSI			_SC_PII_OSI
+    _SC_POLL,
+#define	_SC_POLL			_SC_POLL
+    _SC_SELECT,
+#define	_SC_SELECT			_SC_SELECT
+    _SC_UIO_MAXIOV,
+#define	_SC_UIO_MAXIOV			_SC_UIO_MAXIOV
+    _SC_IOV_MAX = _SC_UIO_MAXIOV,
+#define _SC_IOV_MAX			_SC_IOV_MAX
+    _SC_PII_INTERNET_STREAM,
+#define	_SC_PII_INTERNET_STREAM		_SC_PII_INTERNET_STREAM
+    _SC_PII_INTERNET_DGRAM,
+#define	_SC_PII_INTERNET_DGRAM		_SC_PII_INTERNET_DGRAM
+    _SC_PII_OSI_COTS,
+#define	_SC_PII_OSI_COTS		_SC_PII_OSI_COTS
+    _SC_PII_OSI_CLTS,
+#define	_SC_PII_OSI_CLTS		_SC_PII_OSI_CLTS
+    _SC_PII_OSI_M,
+#define	_SC_PII_OSI_M			_SC_PII_OSI_M
+    _SC_T_IOV_MAX,
+#define	_SC_T_IOV_MAX			_SC_T_IOV_MAX
+
+    /* Values according to POSIX 1003.1c (POSIX threads).  */
+    _SC_THREADS,
+#define	_SC_THREADS			_SC_THREADS
+    _SC_THREAD_SAFE_FUNCTIONS,
+#define _SC_THREAD_SAFE_FUNCTIONS	_SC_THREAD_SAFE_FUNCTIONS
+    _SC_GETGR_R_SIZE_MAX,
+#define	_SC_GETGR_R_SIZE_MAX		_SC_GETGR_R_SIZE_MAX
+    _SC_GETPW_R_SIZE_MAX,
+#define	_SC_GETPW_R_SIZE_MAX		_SC_GETPW_R_SIZE_MAX
+    _SC_LOGIN_NAME_MAX,
+#define	_SC_LOGIN_NAME_MAX		_SC_LOGIN_NAME_MAX
+    _SC_TTY_NAME_MAX,
+#define	_SC_TTY_NAME_MAX		_SC_TTY_NAME_MAX
+    _SC_THREAD_DESTRUCTOR_ITERATIONS,
+#define	_SC_THREAD_DESTRUCTOR_ITERATIONS _SC_THREAD_DESTRUCTOR_ITERATIONS
+    _SC_THREAD_KEYS_MAX,
+#define	_SC_THREAD_KEYS_MAX		_SC_THREAD_KEYS_MAX
+    _SC_THREAD_STACK_MIN,
+#define	_SC_THREAD_STACK_MIN		_SC_THREAD_STACK_MIN
+    _SC_THREAD_THREADS_MAX,
+#define	_SC_THREAD_THREADS_MAX		_SC_THREAD_THREADS_MAX
+    _SC_THREAD_ATTR_STACKADDR,
+#define	_SC_THREAD_ATTR_STACKADDR	_SC_THREAD_ATTR_STACKADDR
+    _SC_THREAD_ATTR_STACKSIZE,
+#define	_SC_THREAD_ATTR_STACKSIZE	_SC_THREAD_ATTR_STACKSIZE
+    _SC_THREAD_PRIORITY_SCHEDULING,
+#define	_SC_THREAD_PRIORITY_SCHEDULING	_SC_THREAD_PRIORITY_SCHEDULING
+    _SC_THREAD_PRIO_INHERIT,
+#define	_SC_THREAD_PRIO_INHERIT		_SC_THREAD_PRIO_INHERIT
+    _SC_THREAD_PRIO_PROTECT,
+#define	_SC_THREAD_PRIO_PROTECT		_SC_THREAD_PRIO_PROTECT
+    _SC_THREAD_PROCESS_SHARED,
+#define	_SC_THREAD_PROCESS_SHARED	_SC_THREAD_PROCESS_SHARED
+
+    _SC_NPROCESSORS_CONF,
+#define _SC_NPROCESSORS_CONF		_SC_NPROCESSORS_CONF
+    _SC_NPROCESSORS_ONLN,
+#define _SC_NPROCESSORS_ONLN		_SC_NPROCESSORS_ONLN
+    _SC_PHYS_PAGES,
+#define _SC_PHYS_PAGES			_SC_PHYS_PAGES
+    _SC_AVPHYS_PAGES,
+#define _SC_AVPHYS_PAGES		_SC_AVPHYS_PAGES
+    _SC_ATEXIT_MAX,
+#define _SC_ATEXIT_MAX			_SC_ATEXIT_MAX
+    _SC_PASS_MAX,
+#define _SC_PASS_MAX			_SC_PASS_MAX
+
+    _SC_XOPEN_VERSION,
+#define _SC_XOPEN_VERSION		_SC_XOPEN_VERSION
+    _SC_XOPEN_XCU_VERSION,
+#define _SC_XOPEN_XCU_VERSION		_SC_XOPEN_XCU_VERSION
+    _SC_XOPEN_UNIX,
+#define _SC_XOPEN_UNIX			_SC_XOPEN_UNIX
+    _SC_XOPEN_CRYPT,
+#define _SC_XOPEN_CRYPT			_SC_XOPEN_CRYPT
+    _SC_XOPEN_ENH_I18N,
+#define _SC_XOPEN_ENH_I18N		_SC_XOPEN_ENH_I18N
+    _SC_XOPEN_SHM,
+#define _SC_XOPEN_SHM			_SC_XOPEN_SHM
+
+    _SC_2_CHAR_TERM,
+#define _SC_2_CHAR_TERM			_SC_2_CHAR_TERM
+    _SC_2_C_VERSION,
+#define _SC_2_C_VERSION			_SC_2_C_VERSION
+    _SC_2_UPE,
+#define _SC_2_UPE			_SC_2_UPE
+
+    _SC_XOPEN_XPG2,
+#define _SC_XOPEN_XPG2			_SC_XOPEN_XPG2
+    _SC_XOPEN_XPG3,
+#define _SC_XOPEN_XPG3			_SC_XOPEN_XPG3
+    _SC_XOPEN_XPG4,
+#define _SC_XOPEN_XPG4			_SC_XOPEN_XPG4
+
+    _SC_CHAR_BIT,
+#define	_SC_CHAR_BIT			_SC_CHAR_BIT
+    _SC_CHAR_MAX,
+#define	_SC_CHAR_MAX			_SC_CHAR_MAX
+    _SC_CHAR_MIN,
+#define	_SC_CHAR_MIN			_SC_CHAR_MIN
+    _SC_INT_MAX,
+#define	_SC_INT_MAX			_SC_INT_MAX
+    _SC_INT_MIN,
+#define	_SC_INT_MIN			_SC_INT_MIN
+    _SC_LONG_BIT,
+#define	_SC_LONG_BIT			_SC_LONG_BIT
+    _SC_WORD_BIT,
+#define	_SC_WORD_BIT			_SC_WORD_BIT
+    _SC_MB_LEN_MAX,
+#define	_SC_MB_LEN_MAX			_SC_MB_LEN_MAX
+    _SC_NZERO,
+#define	_SC_NZERO			_SC_NZERO
+    _SC_SSIZE_MAX,
+#define	_SC_SSIZE_MAX			_SC_SSIZE_MAX
+    _SC_SCHAR_MAX,
+#define	_SC_SCHAR_MAX			_SC_SCHAR_MAX
+    _SC_SCHAR_MIN,
+#define	_SC_SCHAR_MIN			_SC_SCHAR_MIN
+    _SC_SHRT_MAX,
+#define	_SC_SHRT_MAX			_SC_SHRT_MAX
+    _SC_SHRT_MIN,
+#define	_SC_SHRT_MIN			_SC_SHRT_MIN
+    _SC_UCHAR_MAX,
+#define	_SC_UCHAR_MAX			_SC_UCHAR_MAX
+    _SC_UINT_MAX,
+#define	_SC_UINT_MAX			_SC_UINT_MAX
+    _SC_ULONG_MAX,
+#define	_SC_ULONG_MAX			_SC_ULONG_MAX
+    _SC_USHRT_MAX,
+#define	_SC_USHRT_MAX			_SC_USHRT_MAX
+
+    _SC_NL_ARGMAX,
+#define	_SC_NL_ARGMAX			_SC_NL_ARGMAX
+    _SC_NL_LANGMAX,
+#define	_SC_NL_LANGMAX			_SC_NL_LANGMAX
+    _SC_NL_MSGMAX,
+#define	_SC_NL_MSGMAX			_SC_NL_MSGMAX
+    _SC_NL_NMAX,
+#define	_SC_NL_NMAX			_SC_NL_NMAX
+    _SC_NL_SETMAX,
+#define	_SC_NL_SETMAX			_SC_NL_SETMAX
+    _SC_NL_TEXTMAX,
+#define	_SC_NL_TEXTMAX			_SC_NL_TEXTMAX
+
+    _SC_XBS5_ILP32_OFF32,
+#define _SC_XBS5_ILP32_OFF32		_SC_XBS5_ILP32_OFF32
+    _SC_XBS5_ILP32_OFFBIG,
+#define _SC_XBS5_ILP32_OFFBIG		_SC_XBS5_ILP32_OFFBIG
+    _SC_XBS5_LP64_OFF64,
+#define _SC_XBS5_LP64_OFF64		_SC_XBS5_LP64_OFF64
+    _SC_XBS5_LPBIG_OFFBIG,
+#define _SC_XBS5_LPBIG_OFFBIG		_SC_XBS5_LPBIG_OFFBIG
+
+    _SC_XOPEN_LEGACY,
+#define _SC_XOPEN_LEGACY		_SC_XOPEN_LEGACY
+    _SC_XOPEN_REALTIME,
+#define _SC_XOPEN_REALTIME		_SC_XOPEN_REALTIME
+    _SC_XOPEN_REALTIME_THREADS,
+#define _SC_XOPEN_REALTIME_THREADS	_SC_XOPEN_REALTIME_THREADS
+
+    _SC_ADVISORY_INFO,
+#define _SC_ADVISORY_INFO		_SC_ADVISORY_INFO
+    _SC_BARRIERS,
+#define _SC_BARRIERS			_SC_BARRIERS
+    _SC_BASE,
+#define _SC_BASE			_SC_BASE
+    _SC_C_LANG_SUPPORT,
+#define _SC_C_LANG_SUPPORT		_SC_C_LANG_SUPPORT
+    _SC_C_LANG_SUPPORT_R,
+#define _SC_C_LANG_SUPPORT_R		_SC_C_LANG_SUPPORT_R
+    _SC_CLOCK_SELECTION,
+#define _SC_CLOCK_SELECTION		_SC_CLOCK_SELECTION
+    _SC_CPUTIME,
+#define _SC_CPUTIME			_SC_CPUTIME
+    _SC_THREAD_CPUTIME,
+#define _SC_THREAD_CPUTIME		_SC_THREAD_CPUTIME
+    _SC_DEVICE_IO,
+#define _SC_DEVICE_IO			_SC_DEVICE_IO
+    _SC_DEVICE_SPECIFIC,
+#define _SC_DEVICE_SPECIFIC		_SC_DEVICE_SPECIFIC
+    _SC_DEVICE_SPECIFIC_R,
+#define _SC_DEVICE_SPECIFIC_R		_SC_DEVICE_SPECIFIC_R
+    _SC_FD_MGMT,
+#define _SC_FD_MGMT			_SC_FD_MGMT
+    _SC_FIFO,
+#define _SC_FIFO			_SC_FIFO
+    _SC_PIPE,
+#define _SC_PIPE			_SC_PIPE
+    _SC_FILE_ATTRIBUTES,
+#define _SC_FILE_ATTRIBUTES		_SC_FILE_ATTRIBUTES
+    _SC_FILE_LOCKING,
+#define _SC_FILE_LOCKING		_SC_FILE_LOCKING
+    _SC_FILE_SYSTEM,
+#define _SC_FILE_SYSTEM			_SC_FILE_SYSTEM
+    _SC_MONOTONIC_CLOCK,
+#define _SC_MONOTONIC_CLOCK		_SC_MONOTONIC_CLOCK
+    _SC_MULTI_PROCESS,
+#define _SC_MULTI_PROCESS		_SC_MULTI_PROCESS
+    _SC_SINGLE_PROCESS,
+#define _SC_SINGLE_PROCESS		_SC_SINGLE_PROCESS
+    _SC_NETWORKING,
+#define _SC_NETWORKING			_SC_NETWORKING
+    _SC_READER_WRITER_LOCKS,
+#define _SC_READER_WRITER_LOCKS		_SC_READER_WRITER_LOCKS
+    _SC_SPIN_LOCKS,
+#define _SC_SPIN_LOCKS			_SC_SPIN_LOCKS
+    _SC_REGEXP,
+#define _SC_REGEXP			_SC_REGEXP
+    _SC_REGEX_VERSION,
+#define _SC_REGEX_VERSION		_SC_REGEX_VERSION
+    _SC_SHELL,
+#define _SC_SHELL			_SC_SHELL
+    _SC_SIGNALS,
+#define _SC_SIGNALS			_SC_SIGNALS
+    _SC_SPAWN,
+#define _SC_SPAWN			_SC_SPAWN
+    _SC_SPORADIC_SERVER,
+#define _SC_SPORADIC_SERVER		_SC_SPORADIC_SERVER
+    _SC_THREAD_SPORADIC_SERVER,
+#define _SC_THREAD_SPORADIC_SERVER	_SC_THREAD_SPORADIC_SERVER
+    _SC_SYSTEM_DATABASE,
+#define _SC_SYSTEM_DATABASE		_SC_SYSTEM_DATABASE
+    _SC_SYSTEM_DATABASE_R,
+#define _SC_SYSTEM_DATABASE_R		_SC_SYSTEM_DATABASE_R
+    _SC_TIMEOUTS,
+#define _SC_TIMEOUTS			_SC_TIMEOUTS
+    _SC_TYPED_MEMORY_OBJECTS,
+#define _SC_TYPED_MEMORY_OBJECTS	_SC_TYPED_MEMORY_OBJECTS
+    _SC_USER_GROUPS,
+#define _SC_USER_GROUPS			_SC_USER_GROUPS
+    _SC_USER_GROUPS_R,
+#define _SC_USER_GROUPS_R		_SC_USER_GROUPS_R
+    _SC_2_PBS,
+#define _SC_2_PBS			_SC_2_PBS
+    _SC_2_PBS_ACCOUNTING,
+#define _SC_2_PBS_ACCOUNTING		_SC_2_PBS_ACCOUNTING
+    _SC_2_PBS_LOCATE,
+#define _SC_2_PBS_LOCATE		_SC_2_PBS_LOCATE
+    _SC_2_PBS_MESSAGE,
+#define _SC_2_PBS_MESSAGE		_SC_2_PBS_MESSAGE
+    _SC_2_PBS_TRACK,
+#define _SC_2_PBS_TRACK			_SC_2_PBS_TRACK
+    _SC_SYMLOOP_MAX,
+#define _SC_SYMLOOP_MAX			_SC_SYMLOOP_MAX
+    _SC_STREAMS,
+#define _SC_STREAMS			_SC_STREAMS
+    _SC_2_PBS_CHECKPOINT,
+#define _SC_2_PBS_CHECKPOINT		_SC_2_PBS_CHECKPOINT
+
+    _SC_V6_ILP32_OFF32,
+#define _SC_V6_ILP32_OFF32		_SC_V6_ILP32_OFF32
+    _SC_V6_ILP32_OFFBIG,
+#define _SC_V6_ILP32_OFFBIG		_SC_V6_ILP32_OFFBIG
+    _SC_V6_LP64_OFF64,
+#define _SC_V6_LP64_OFF64		_SC_V6_LP64_OFF64
+    _SC_V6_LPBIG_OFFBIG,
+#define _SC_V6_LPBIG_OFFBIG		_SC_V6_LPBIG_OFFBIG
+
+    _SC_HOST_NAME_MAX,
+#define _SC_HOST_NAME_MAX		_SC_HOST_NAME_MAX
+    _SC_TRACE,
+#define _SC_TRACE			_SC_TRACE
+    _SC_TRACE_EVENT_FILTER,
+#define _SC_TRACE_EVENT_FILTER		_SC_TRACE_EVENT_FILTER
+    _SC_TRACE_INHERIT,
+#define _SC_TRACE_INHERIT		_SC_TRACE_INHERIT
+    _SC_TRACE_LOG,
+#define _SC_TRACE_LOG			_SC_TRACE_LOG
+
+    _SC_LEVEL1_ICACHE_SIZE,
+#define _SC_LEVEL1_ICACHE_SIZE		_SC_LEVEL1_ICACHE_SIZE
+    _SC_LEVEL1_ICACHE_ASSOC,
+#define _SC_LEVEL1_ICACHE_ASSOC		_SC_LEVEL1_ICACHE_ASSOC
+    _SC_LEVEL1_ICACHE_LINESIZE,
+#define _SC_LEVEL1_ICACHE_LINESIZE	_SC_LEVEL1_ICACHE_LINESIZE
+    _SC_LEVEL1_DCACHE_SIZE,
+#define _SC_LEVEL1_DCACHE_SIZE		_SC_LEVEL1_DCACHE_SIZE
+    _SC_LEVEL1_DCACHE_ASSOC,
+#define _SC_LEVEL1_DCACHE_ASSOC		_SC_LEVEL1_DCACHE_ASSOC
+    _SC_LEVEL1_DCACHE_LINESIZE,
+#define _SC_LEVEL1_DCACHE_LINESIZE	_SC_LEVEL1_DCACHE_LINESIZE
+    _SC_LEVEL2_CACHE_SIZE,
+#define _SC_LEVEL2_CACHE_SIZE		_SC_LEVEL2_CACHE_SIZE
+    _SC_LEVEL2_CACHE_ASSOC,
+#define _SC_LEVEL2_CACHE_ASSOC		_SC_LEVEL2_CACHE_ASSOC
+    _SC_LEVEL2_CACHE_LINESIZE,
+#define _SC_LEVEL2_CACHE_LINESIZE	_SC_LEVEL2_CACHE_LINESIZE
+    _SC_LEVEL3_CACHE_SIZE,
+#define _SC_LEVEL3_CACHE_SIZE		_SC_LEVEL3_CACHE_SIZE
+    _SC_LEVEL3_CACHE_ASSOC,
+#define _SC_LEVEL3_CACHE_ASSOC		_SC_LEVEL3_CACHE_ASSOC
+    _SC_LEVEL3_CACHE_LINESIZE,
+#define _SC_LEVEL3_CACHE_LINESIZE	_SC_LEVEL3_CACHE_LINESIZE
+    _SC_LEVEL4_CACHE_SIZE,
+#define _SC_LEVEL4_CACHE_SIZE		_SC_LEVEL4_CACHE_SIZE
+    _SC_LEVEL4_CACHE_ASSOC,
+#define _SC_LEVEL4_CACHE_ASSOC		_SC_LEVEL4_CACHE_ASSOC
+    _SC_LEVEL4_CACHE_LINESIZE,
+#define _SC_LEVEL4_CACHE_LINESIZE	_SC_LEVEL4_CACHE_LINESIZE
+    /* Leave room here, maybe we need a few more cache levels some day.  */
+
+    _SC_IPV6 = _SC_LEVEL1_ICACHE_SIZE + 50,
+#define _SC_IPV6			_SC_IPV6
+    _SC_RAW_SOCKETS,
+#define _SC_RAW_SOCKETS			_SC_RAW_SOCKETS
+
+    _SC_V7_ILP32_OFF32,
+#define _SC_V7_ILP32_OFF32		_SC_V7_ILP32_OFF32
+    _SC_V7_ILP32_OFFBIG,
+#define _SC_V7_ILP32_OFFBIG		_SC_V7_ILP32_OFFBIG
+    _SC_V7_LP64_OFF64,
+#define _SC_V7_LP64_OFF64		_SC_V7_LP64_OFF64
+    _SC_V7_LPBIG_OFFBIG,
+#define _SC_V7_LPBIG_OFFBIG		_SC_V7_LPBIG_OFFBIG
+
+    _SC_SS_REPL_MAX,
+#define _SC_SS_REPL_MAX			_SC_SS_REPL_MAX
+
+    _SC_TRACE_EVENT_NAME_MAX,
+#define _SC_TRACE_EVENT_NAME_MAX	_SC_TRACE_EVENT_NAME_MAX
+    _SC_TRACE_NAME_MAX,
+#define _SC_TRACE_NAME_MAX		_SC_TRACE_NAME_MAX
+    _SC_TRACE_SYS_MAX,
+#define _SC_TRACE_SYS_MAX		_SC_TRACE_SYS_MAX
+    _SC_TRACE_USER_EVENT_MAX,
+#define _SC_TRACE_USER_EVENT_MAX	_SC_TRACE_USER_EVENT_MAX
+
+    _SC_XOPEN_STREAMS,
+#define _SC_XOPEN_STREAMS		_SC_XOPEN_STREAMS
+
+    _SC_THREAD_ROBUST_PRIO_INHERIT,
+#define _SC_THREAD_ROBUST_PRIO_INHERIT	_SC_THREAD_ROBUST_PRIO_INHERIT
+    _SC_THREAD_ROBUST_PRIO_PROTECT,
+#define _SC_THREAD_ROBUST_PRIO_PROTECT	_SC_THREAD_ROBUST_PRIO_PROTECT
+
+    _SC_MINSIGSTKSZ,
+#define	_SC_MINSIGSTKSZ			_SC_MINSIGSTKSZ
+
+    _SC_SIGSTKSZ
+#define	_SC_SIGSTKSZ			_SC_SIGSTKSZ
+  };
+
+/* Values for the NAME argument to `confstr'.  */
+enum
+  {
+    _CS_PATH,			/* The default search path.  */
+#define _CS_PATH		_CS_PATH
+
+    _CS_V6_WIDTH_RESTRICTED_ENVS,
+#define _CS_V6_WIDTH_RESTRICTED_ENVS	_CS_V6_WIDTH_RESTRICTED_ENVS
+#define _CS_POSIX_V6_WIDTH_RESTRICTED_ENVS	_CS_V6_WIDTH_RESTRICTED_ENVS
+
+    _CS_GNU_LIBC_VERSION,
+#define _CS_GNU_LIBC_VERSION	_CS_GNU_LIBC_VERSION
+    _CS_GNU_LIBPTHREAD_VERSION,
+#define _CS_GNU_LIBPTHREAD_VERSION	_CS_GNU_LIBPTHREAD_VERSION
+
+    _CS_V5_WIDTH_RESTRICTED_ENVS,
+#define _CS_V5_WIDTH_RESTRICTED_ENVS	_CS_V5_WIDTH_RESTRICTED_ENVS
+#define _CS_POSIX_V5_WIDTH_RESTRICTED_ENVS	_CS_V5_WIDTH_RESTRICTED_ENVS
+
+    _CS_V7_WIDTH_RESTRICTED_ENVS,
+#define _CS_V7_WIDTH_RESTRICTED_ENVS	_CS_V7_WIDTH_RESTRICTED_ENVS
+#define _CS_POSIX_V7_WIDTH_RESTRICTED_ENVS	_CS_V7_WIDTH_RESTRICTED_ENVS
+
+    _CS_LFS_CFLAGS = 1000,
+#define _CS_LFS_CFLAGS	_CS_LFS_CFLAGS
+    _CS_LFS_LDFLAGS,
+#define _CS_LFS_LDFLAGS	_CS_LFS_LDFLAGS
+    _CS_LFS_LIBS,
+#define _CS_LFS_LIBS		_CS_LFS_LIBS
+    _CS_LFS_LINTFLAGS,
+#define _CS_LFS_LINTFLAGS	_CS_LFS_LINTFLAGS
+    _CS_LFS64_CFLAGS,
+#define _CS_LFS64_CFLAGS	_CS_LFS64_CFLAGS
+    _CS_LFS64_LDFLAGS,
+#define _CS_LFS64_LDFLAGS	_CS_LFS64_LDFLAGS
+    _CS_LFS64_LIBS,
+#define _CS_LFS64_LIBS	_CS_LFS64_LIBS
+    _CS_LFS64_LINTFLAGS,
+#define _CS_LFS64_LINTFLAGS	_CS_LFS64_LINTFLAGS
+
+    _CS_XBS5_ILP32_OFF32_CFLAGS = 1100,
+#define _CS_XBS5_ILP32_OFF32_CFLAGS _CS_XBS5_ILP32_OFF32_CFLAGS
+    _CS_XBS5_ILP32_OFF32_LDFLAGS,
+#define _CS_XBS5_ILP32_OFF32_LDFLAGS _CS_XBS5_ILP32_OFF32_LDFLAGS
+    _CS_XBS5_ILP32_OFF32_LIBS,
+#define _CS_XBS5_ILP32_OFF32_LIBS _CS_XBS5_ILP32_OFF32_LIBS
+    _CS_XBS5_ILP32_OFF32_LINTFLAGS,
+#define _CS_XBS5_ILP32_OFF32_LINTFLAGS _CS_XBS5_ILP32_OFF32_LINTFLAGS
+    _CS_XBS5_ILP32_OFFBIG_CFLAGS,
+#define _CS_XBS5_ILP32_OFFBIG_CFLAGS _CS_XBS5_ILP32_OFFBIG_CFLAGS
+    _CS_XBS5_ILP32_OFFBIG_LDFLAGS,
+#define _CS_XBS5_ILP32_OFFBIG_LDFLAGS _CS_XBS5_ILP32_OFFBIG_LDFLAGS
+    _CS_XBS5_ILP32_OFFBIG_LIBS,
+#define _CS_XBS5_ILP32_OFFBIG_LIBS _CS_XBS5_ILP32_OFFBIG_LIBS
+    _CS_XBS5_ILP32_OFFBIG_LINTFLAGS,
+#define _CS_XBS5_ILP32_OFFBIG_LINTFLAGS _CS_XBS5_ILP32_OFFBIG_LINTFLAGS
+    _CS_XBS5_LP64_OFF64_CFLAGS,
+#define _CS_XBS5_LP64_OFF64_CFLAGS _CS_XBS5_LP64_OFF64_CFLAGS
+    _CS_XBS5_LP64_OFF64_LDFLAGS,
+#define _CS_XBS5_LP64_OFF64_LDFLAGS _CS_XBS5_LP64_OFF64_LDFLAGS
+    _CS_XBS5_LP64_OFF64_LIBS,
+#define _CS_XBS5_LP64_OFF64_LIBS _CS_XBS5_LP64_OFF64_LIBS
+    _CS_XBS5_LP64_OFF64_LINTFLAGS,
+#define _CS_XBS5_LP64_OFF64_LINTFLAGS _CS_XBS5_LP64_OFF64_LINTFLAGS
+    _CS_XBS5_LPBIG_OFFBIG_CFLAGS,
+#define _CS_XBS5_LPBIG_OFFBIG_CFLAGS _CS_XBS5_LPBIG_OFFBIG_CFLAGS
+    _CS_XBS5_LPBIG_OFFBIG_LDFLAGS,
+#define _CS_XBS5_LPBIG_OFFBIG_LDFLAGS _CS_XBS5_LPBIG_OFFBIG_LDFLAGS
+    _CS_XBS5_LPBIG_OFFBIG_LIBS,
+#define _CS_XBS5_LPBIG_OFFBIG_LIBS _CS_XBS5_LPBIG_OFFBIG_LIBS
+    _CS_XBS5_LPBIG_OFFBIG_LINTFLAGS,
+#define _CS_XBS5_LPBIG_OFFBIG_LINTFLAGS _CS_XBS5_LPBIG_OFFBIG_LINTFLAGS
+
+    _CS_POSIX_V6_ILP32_OFF32_CFLAGS,
+#define _CS_POSIX_V6_ILP32_OFF32_CFLAGS _CS_POSIX_V6_ILP32_OFF32_CFLAGS
+    _CS_POSIX_V6_ILP32_OFF32_LDFLAGS,
+#define _CS_POSIX_V6_ILP32_OFF32_LDFLAGS _CS_POSIX_V6_ILP32_OFF32_LDFLAGS
+    _CS_POSIX_V6_ILP32_OFF32_LIBS,
+#define _CS_POSIX_V6_ILP32_OFF32_LIBS _CS_POSIX_V6_ILP32_OFF32_LIBS
+    _CS_POSIX_V6_ILP32_OFF32_LINTFLAGS,
+#define _CS_POSIX_V6_ILP32_OFF32_LINTFLAGS _CS_POSIX_V6_ILP32_OFF32_LINTFLAGS
+    _CS_POSIX_V6_ILP32_OFFBIG_CFLAGS,
+#define _CS_POSIX_V6_ILP32_OFFBIG_CFLAGS _CS_POSIX_V6_ILP32_OFFBIG_CFLAGS
+    _CS_POSIX_V6_ILP32_OFFBIG_LDFLAGS,
+#define _CS_POSIX_V6_ILP32_OFFBIG_LDFLAGS _CS_POSIX_V6_ILP32_OFFBIG_LDFLAGS
+    _CS_POSIX_V6_ILP32_OFFBIG_LIBS,
+#define _CS_POSIX_V6_ILP32_OFFBIG_LIBS _CS_POSIX_V6_ILP32_OFFBIG_LIBS
+    _CS_POSIX_V6_ILP32_OFFBIG_LINTFLAGS,
+#define _CS_POSIX_V6_ILP32_OFFBIG_LINTFLAGS _CS_POSIX_V6_ILP32_OFFBIG_LINTFLAGS
+    _CS_POSIX_V6_LP64_OFF64_CFLAGS,
+#define _CS_POSIX_V6_LP64_OFF64_CFLAGS _CS_POSIX_V6_LP64_OFF64_CFLAGS
+    _CS_POSIX_V6_LP64_OFF64_LDFLAGS,
+#define _CS_POSIX_V6_LP64_OFF64_LDFLAGS _CS_POSIX_V6_LP64_OFF64_LDFLAGS
+    _CS_POSIX_V6_LP64_OFF64_LIBS,
+#define _CS_POSIX_V6_LP64_OFF64_LIBS _CS_POSIX_V6_LP64_OFF64_LIBS
+    _CS_POSIX_V6_LP64_OFF64_LINTFLAGS,
+#define _CS_POSIX_V6_LP64_OFF64_LINTFLAGS _CS_POSIX_V6_LP64_OFF64_LINTFLAGS
+    _CS_POSIX_V6_LPBIG_OFFBIG_CFLAGS,
+#define _CS_POSIX_V6_LPBIG_OFFBIG_CFLAGS _CS_POSIX_V6_LPBIG_OFFBIG_CFLAGS
+    _CS_POSIX_V6_LPBIG_OFFBIG_LDFLAGS,
+#define _CS_POSIX_V6_LPBIG_OFFBIG_LDFLAGS _CS_POSIX_V6_LPBIG_OFFBIG_LDFLAGS
+    _CS_POSIX_V6_LPBIG_OFFBIG_LIBS,
+#define _CS_POSIX_V6_LPBIG_OFFBIG_LIBS _CS_POSIX_V6_LPBIG_OFFBIG_LIBS
+    _CS_POSIX_V6_LPBIG_OFFBIG_LINTFLAGS,
+#define _CS_POSIX_V6_LPBIG_OFFBIG_LINTFLAGS _CS_POSIX_V6_LPBIG_OFFBIG_LINTFLAGS
+
+    _CS_POSIX_V7_ILP32_OFF32_CFLAGS,
+#define _CS_POSIX_V7_ILP32_OFF32_CFLAGS _CS_POSIX_V7_ILP32_OFF32_CFLAGS
+    _CS_POSIX_V7_ILP32_OFF32_LDFLAGS,
+#define _CS_POSIX_V7_ILP32_OFF32_LDFLAGS _CS_POSIX_V7_ILP32_OFF32_LDFLAGS
+    _CS_POSIX_V7_ILP32_OFF32_LIBS,
+#define _CS_POSIX_V7_ILP32_OFF32_LIBS _CS_POSIX_V7_ILP32_OFF32_LIBS
+    _CS_POSIX_V7_ILP32_OFF32_LINTFLAGS,
+#define _CS_POSIX_V7_ILP32_OFF32_LINTFLAGS _CS_POSIX_V7_ILP32_OFF32_LINTFLAGS
+    _CS_POSIX_V7_ILP32_OFFBIG_CFLAGS,
+#define _CS_POSIX_V7_ILP32_OFFBIG_CFLAGS _CS_POSIX_V7_ILP32_OFFBIG_CFLAGS
+    _CS_POSIX_V7_ILP32_OFFBIG_LDFLAGS,
+#define _CS_POSIX_V7_ILP32_OFFBIG_LDFLAGS _CS_POSIX_V7_ILP32_OFFBIG_LDFLAGS
+    _CS_POSIX_V7_ILP32_OFFBIG_LIBS,
+#define _CS_POSIX_V7_ILP32_OFFBIG_LIBS _CS_POSIX_V7_ILP32_OFFBIG_LIBS
+    _CS_POSIX_V7_ILP32_OFFBIG_LINTFLAGS,
+#define _CS_POSIX_V7_ILP32_OFFBIG_LINTFLAGS _CS_POSIX_V7_ILP32_OFFBIG_LINTFLAGS
+    _CS_POSIX_V7_LP64_OFF64_CFLAGS,
+#define _CS_POSIX_V7_LP64_OFF64_CFLAGS _CS_POSIX_V7_LP64_OFF64_CFLAGS
+    _CS_POSIX_V7_LP64_OFF64_LDFLAGS,
+#define _CS_POSIX_V7_LP64_OFF64_LDFLAGS _CS_POSIX_V7_LP64_OFF64_LDFLAGS
+    _CS_POSIX_V7_LP64_OFF64_LIBS,
+#define _CS_POSIX_V7_LP64_OFF64_LIBS _CS_POSIX_V7_LP64_OFF64_LIBS
+    _CS_POSIX_V7_LP64_OFF64_LINTFLAGS,
+#define _CS_POSIX_V7_LP64_OFF64_LINTFLAGS _CS_POSIX_V7_LP64_OFF64_LINTFLAGS
+    _CS_POSIX_V7_LPBIG_OFFBIG_CFLAGS,
+#define _CS_POSIX_V7_LPBIG_OFFBIG_CFLAGS _CS_POSIX_V7_LPBIG_OFFBIG_CFLAGS
+    _CS_POSIX_V7_LPBIG_OFFBIG_LDFLAGS,
+#define _CS_POSIX_V7_LPBIG_OFFBIG_LDFLAGS _CS_POSIX_V7_LPBIG_OFFBIG_LDFLAGS
+    _CS_POSIX_V7_LPBIG_OFFBIG_LIBS,
+#define _CS_POSIX_V7_LPBIG_OFFBIG_LIBS _CS_POSIX_V7_LPBIG_OFFBIG_LIBS
+    _CS_POSIX_V7_LPBIG_OFFBIG_LINTFLAGS,
+#define _CS_POSIX_V7_LPBIG_OFFBIG_LINTFLAGS _CS_POSIX_V7_LPBIG_OFFBIG_LINTFLAGS
+
+    _CS_V6_ENV,
+#define _CS_V6_ENV			_CS_V6_ENV
+    _CS_V7_ENV
+#define _CS_V7_ENV			_CS_V7_ENV
+  };
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@confname.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@confname.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@cpu-set.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@cpu-set.h
new file mode 100644
index 0000000000000000000000000000000000000000..afc1622f7ea4063ea1bd84e20d491d72e378376c
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@cpu-set.h
@@ -0,0 +1,124 @@
+/* Definition of the cpu_set_t structure used by the POSIX 1003.1b-1993
+   scheduling interface.
+   Copyright (C) 1996-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _BITS_CPU_SET_H
+#define _BITS_CPU_SET_H 1
+
+#ifndef _SCHED_H
+# error "Never include <bits/cpu-set.h> directly; use <sched.h> instead."
+#endif
+
+/* Size definition for CPU sets.  */
+#define __CPU_SETSIZE	1024
+#define __NCPUBITS	(8 * sizeof (__cpu_mask))
+
+/* Type for array elements in 'cpu_set_t'.  */
+typedef __CPU_MASK_TYPE __cpu_mask;
+
+/* Basic access functions.  */
+#define __CPUELT(cpu)	((cpu) / __NCPUBITS)
+#define __CPUMASK(cpu)	((__cpu_mask) 1 << ((cpu) % __NCPUBITS))
+
+/* Data structure to describe CPU mask.  */
+typedef struct
+{
+  __cpu_mask __bits[__CPU_SETSIZE / __NCPUBITS];
+} cpu_set_t;
+
+/* Access functions for CPU masks.  */
+#if __GNUC_PREREQ (2, 91)
+# define __CPU_ZERO_S(setsize, cpusetp) \
+  do __builtin_memset (cpusetp, '\0', setsize); while (0)
+#else
+# define __CPU_ZERO_S(setsize, cpusetp) \
+  do {									      \
+    size_t __i;								      \
+    size_t __imax = (setsize) / sizeof (__cpu_mask);			      \
+    __cpu_mask *__bits = (cpusetp)->__bits;				      \
+    for (__i = 0; __i < __imax; ++__i)					      \
+      __bits[__i] = 0;							      \
+  } while (0)
+#endif
+#define __CPU_SET_S(cpu, setsize, cpusetp) \
+  (__extension__							      \
+   ({ size_t __cpu = (cpu);						      \
+      __cpu / 8 < (setsize)						      \
+      ? (((__cpu_mask *) ((cpusetp)->__bits))[__CPUELT (__cpu)]		      \
+	 |= __CPUMASK (__cpu))						      \
+      : 0; }))
+#define __CPU_CLR_S(cpu, setsize, cpusetp) \
+  (__extension__							      \
+   ({ size_t __cpu = (cpu);						      \
+      __cpu / 8 < (setsize)						      \
+      ? (((__cpu_mask *) ((cpusetp)->__bits))[__CPUELT (__cpu)]		      \
+	 &= ~__CPUMASK (__cpu))						      \
+      : 0; }))
+#define __CPU_ISSET_S(cpu, setsize, cpusetp) \
+  (__extension__							      \
+   ({ size_t __cpu = (cpu);						      \
+      __cpu / 8 < (setsize)						      \
+      ? ((((const __cpu_mask *) ((cpusetp)->__bits))[__CPUELT (__cpu)]	      \
+	  & __CPUMASK (__cpu))) != 0					      \
+      : 0; }))
+
+#define __CPU_COUNT_S(setsize, cpusetp) \
+  __sched_cpucount (setsize, cpusetp)
+
+#if __GNUC_PREREQ (2, 91)
+# define __CPU_EQUAL_S(setsize, cpusetp1, cpusetp2) \
+  (__builtin_memcmp (cpusetp1, cpusetp2, setsize) == 0)
+#else
+# define __CPU_EQUAL_S(setsize, cpusetp1, cpusetp2) \
+  (__extension__							      \
+   ({ const __cpu_mask *__arr1 = (cpusetp1)->__bits;			      \
+      const __cpu_mask *__arr2 = (cpusetp2)->__bits;			      \
+      size_t __imax = (setsize) / sizeof (__cpu_mask);			      \
+      size_t __i;							      \
+      for (__i = 0; __i < __imax; ++__i)				      \
+	if (__arr1[__i] != __arr2[__i])					      \
+	  break;							      \
+      __i == __imax; }))
+#endif
+
+#define __CPU_OP_S(setsize, destset, srcset1, srcset2, op) \
+  (__extension__							      \
+   ({ cpu_set_t *__dest = (destset);					      \
+      const __cpu_mask *__arr1 = (srcset1)->__bits;			      \
+      const __cpu_mask *__arr2 = (srcset2)->__bits;			      \
+      size_t __imax = (setsize) / sizeof (__cpu_mask);			      \
+      size_t __i;							      \
+      for (__i = 0; __i < __imax; ++__i)				      \
+	((__cpu_mask *) __dest->__bits)[__i] = __arr1[__i] op __arr2[__i];    \
+      __dest; }))
+
+#define __CPU_ALLOC_SIZE(count) \
+  ((((count) + __NCPUBITS - 1) / __NCPUBITS) * sizeof (__cpu_mask))
+#define __CPU_ALLOC(count) __sched_cpualloc (count)
+#define __CPU_FREE(cpuset) __sched_cpufree (cpuset)
+
+__BEGIN_DECLS
+
+extern int __sched_cpucount (size_t __setsize, const cpu_set_t *__setp)
+     __THROW;
+extern cpu_set_t *__sched_cpualloc (size_t __count) __THROW __wur;
+extern void __sched_cpufree (cpu_set_t *__set) __THROW;
+
+__END_DECLS
+
+#endif /* bits/cpu-set.h */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@cpu-set.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@cpu-set.h.blob
new file mode 100644
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@endian.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@endian.h
new file mode 100644
index 0000000000000000000000000000000000000000..1160e899d1a9d652635ff114ae3e59f0cdfbf688
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@endian.h
@@ -0,0 +1,49 @@
+/* Endian macros for string.h functions
+   Copyright (C) 1992-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#ifndef _BITS_ENDIAN_H
+#define _BITS_ENDIAN_H 1
+
+/* Definitions for byte order, according to significance of bytes,
+   from low addresses to high addresses.  The value is what you get by
+   putting '4' in the most significant byte, '3' in the second most
+   significant byte, '2' in the second least significant byte, and '1'
+   in the least significant byte, and then writing down one digit for
+   each byte, starting with the byte at the lowest address at the left,
+   and proceeding to the byte with the highest address at the right.  */
+
+#define	__LITTLE_ENDIAN	1234
+#define	__BIG_ENDIAN	4321
+#define	__PDP_ENDIAN	3412
+
+/* This file defines `__BYTE_ORDER' for the particular machine.  */
+#include <bits/endianness.h>
+
+/* Some machines may need to use a different endianness for floating point
+   values.  */
+#ifndef __FLOAT_WORD_ORDER
+# define __FLOAT_WORD_ORDER __BYTE_ORDER
+#endif
+
+#if __BYTE_ORDER == __LITTLE_ENDIAN
+# define __LONG_LONG_PAIR(HI, LO) LO, HI
+#elif __BYTE_ORDER == __BIG_ENDIAN
+# define __LONG_LONG_PAIR(HI, LO) HI, LO
+#endif
+
+#endif /* bits/endian.h */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@endian.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@endian.h.blob
new file mode 100644
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Binary files /dev/null and b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@endian.h.blob differ
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@endianness.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@endianness.h
new file mode 100644
index 0000000000000000000000000000000000000000..962a9ae4d6e9e012b82ab31fe2f567efb6c4c001
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@endianness.h
@@ -0,0 +1,11 @@
+#ifndef _BITS_ENDIANNESS_H
+#define _BITS_ENDIANNESS_H 1
+
+#ifndef _BITS_ENDIAN_H
+# error "Never use <bits/endianness.h> directly; include <endian.h> instead."
+#endif
+
+/* i386/x86_64 are little-endian.  */
+#define __BYTE_ORDER __LITTLE_ENDIAN
+
+#endif /* bits/endianness.h */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@endianness.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@endianness.h.blob
new file mode 100644
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Binary files /dev/null and b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@endianness.h.blob differ
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@environments.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@environments.h
new file mode 100644
index 0000000000000000000000000000000000000000..7b8604353158524b4631d88738c172ad2a180a15
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@environments.h
@@ -0,0 +1,105 @@
+/* Copyright (C) 1999-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _UNISTD_H
+# error "Never include this file directly.  Use <unistd.h> instead"
+#endif
+
+#include <bits/wordsize.h>
+
+/* This header should define the following symbols under the described
+   situations.  A value `1' means that the model is always supported,
+   `-1' means it is never supported.  Undefined means it cannot be
+   statically decided.
+
+   _POSIX_V7_ILP32_OFF32   32bit int, long, pointers, and off_t type
+   _POSIX_V7_ILP32_OFFBIG  32bit int, long, and pointers and larger off_t type
+
+   _POSIX_V7_LP64_OFF32	   64bit long and pointers and 32bit off_t type
+   _POSIX_V7_LPBIG_OFFBIG  64bit long and pointers and large off_t type
+
+   The macros _POSIX_V6_ILP32_OFF32, _POSIX_V6_ILP32_OFFBIG,
+   _POSIX_V6_LP64_OFF32, _POSIX_V6_LPBIG_OFFBIG, _XBS5_ILP32_OFF32,
+   _XBS5_ILP32_OFFBIG, _XBS5_LP64_OFF32, and _XBS5_LPBIG_OFFBIG were
+   used in previous versions of the Unix standard and are available
+   only for compatibility.
+*/
+
+#if __WORDSIZE == 64
+
+/* Environments with 32-bit wide pointers are optionally provided.
+   Therefore following macros aren't defined:
+   # undef _POSIX_V7_ILP32_OFF32
+   # undef _POSIX_V7_ILP32_OFFBIG
+   # undef _POSIX_V6_ILP32_OFF32
+   # undef _POSIX_V6_ILP32_OFFBIG
+   # undef _XBS5_ILP32_OFF32
+   # undef _XBS5_ILP32_OFFBIG
+   and users need to check at runtime.  */
+
+/* We also have no use (for now) for an environment with bigger pointers
+   and offsets.  */
+# define _POSIX_V7_LPBIG_OFFBIG	-1
+# define _POSIX_V6_LPBIG_OFFBIG	-1
+# define _XBS5_LPBIG_OFFBIG	-1
+
+/* By default we have 64-bit wide `long int', pointers and `off_t'.  */
+# define _POSIX_V7_LP64_OFF64	1
+# define _POSIX_V6_LP64_OFF64	1
+# define _XBS5_LP64_OFF64	1
+
+#else /* __WORDSIZE == 32 */
+
+/* We have 32-bit wide `int', `long int' and pointers and all platforms
+   support LFS.  -mx32 has 64-bit wide `off_t'.  */
+# define _POSIX_V7_ILP32_OFFBIG	1
+# define _POSIX_V6_ILP32_OFFBIG 1
+# define _XBS5_ILP32_OFFBIG	1
+
+# ifndef __x86_64__
+/* -m32 has 32-bit wide `off_t'.  */
+#  define _POSIX_V7_ILP32_OFF32	1
+#  define _POSIX_V6_ILP32_OFF32	1
+#  define _XBS5_ILP32_OFF32	1
+# endif
+
+/* We optionally provide an environment with the above size but an 64-bit
+   side `off_t'.  Therefore we don't define _POSIX_V7_ILP32_OFFBIG.  */
+
+/* Environments with 64-bit wide pointers can be provided,
+   so these macros aren't defined:
+   # undef _POSIX_V7_LP64_OFF64
+   # undef _POSIX_V7_LPBIG_OFFBIG
+   # undef _POSIX_V6_LP64_OFF64
+   # undef _POSIX_V6_LPBIG_OFFBIG
+   # undef _XBS5_LP64_OFF64
+   # undef _XBS5_LPBIG_OFFBIG
+   and sysconf tests for it at runtime.  */
+
+#endif /* __WORDSIZE == 32 */
+
+#define __ILP32_OFF32_CFLAGS	"-m32"
+#define __ILP32_OFF32_LDFLAGS	"-m32"
+#if defined __x86_64__ && defined __ILP32__
+# define __ILP32_OFFBIG_CFLAGS	"-mx32"
+# define __ILP32_OFFBIG_LDFLAGS	"-mx32"
+#else
+# define __ILP32_OFFBIG_CFLAGS	"-m32 -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64"
+# define __ILP32_OFFBIG_LDFLAGS	"-m32"
+#endif
+#define __LP64_OFF64_CFLAGS	"-m64"
+#define __LP64_OFF64_LDFLAGS	"-m64"
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@environments.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@environments.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@errno.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@errno.h
new file mode 100644
index 0000000000000000000000000000000000000000..77907123e2ed912b8f1710bfd5906c8b2fd99a47
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@errno.h
@@ -0,0 +1,53 @@
+/* Error constants.  Linux specific version.
+   Copyright (C) 1996-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _BITS_ERRNO_H
+#define _BITS_ERRNO_H 1
+
+#if !defined _ERRNO_H
+# error "Never include <bits/errno.h> directly; use <errno.h> instead."
+#endif
+
+# include <linux/errno.h>
+
+/* Older Linux headers do not define these constants.  */
+# ifndef ENOTSUP
+#  define ENOTSUP		EOPNOTSUPP
+# endif
+
+# ifndef ECANCELED
+#  define ECANCELED		125
+# endif
+
+# ifndef EOWNERDEAD
+#  define EOWNERDEAD		130
+# endif
+
+#ifndef ENOTRECOVERABLE
+#  define ENOTRECOVERABLE	131
+# endif
+
+# ifndef ERFKILL
+#  define ERFKILL		132
+# endif
+
+# ifndef EHWPOISON
+#  define EHWPOISON		133
+# endif
+
+#endif /* bits/errno.h.  */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@errno.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@errno.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@fenv.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@fenv.h
new file mode 100644
index 0000000000000000000000000000000000000000..34eeb14aff6a7a5d4d47cafb2cd9b8eab81c5842
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@fenv.h
@@ -0,0 +1,116 @@
+/* Copyright (C) 1997-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _FENV_H
+# error "Never use <bits/fenv.h> directly; include <fenv.h> instead."
+#endif
+
+/* Define bits representing the exception.  We use the bit positions
+   of the appropriate bits in the FPU control word.  */
+enum
+  {
+    FE_INVALID =
+#define FE_INVALID	0x01
+      FE_INVALID,
+    __FE_DENORM = 0x02,
+    FE_DIVBYZERO =
+#define FE_DIVBYZERO	0x04
+      FE_DIVBYZERO,
+    FE_OVERFLOW =
+#define FE_OVERFLOW	0x08
+      FE_OVERFLOW,
+    FE_UNDERFLOW =
+#define FE_UNDERFLOW	0x10
+      FE_UNDERFLOW,
+    FE_INEXACT =
+#define FE_INEXACT	0x20
+      FE_INEXACT
+  };
+
+#define FE_ALL_EXCEPT \
+	(FE_INEXACT | FE_DIVBYZERO | FE_UNDERFLOW | FE_OVERFLOW | FE_INVALID)
+
+/* The ix87 FPU supports all of the four defined rounding modes.  We
+   use again the bit positions in the FPU control word as the values
+   for the appropriate macros.  */
+enum
+  {
+    FE_TONEAREST =
+#define FE_TONEAREST	0
+      FE_TONEAREST,
+    FE_DOWNWARD =
+#define FE_DOWNWARD	0x400
+      FE_DOWNWARD,
+    FE_UPWARD =
+#define FE_UPWARD	0x800
+      FE_UPWARD,
+    FE_TOWARDZERO =
+#define FE_TOWARDZERO	0xc00
+      FE_TOWARDZERO
+  };
+
+
+/* Type representing exception flags.  */
+typedef unsigned short int fexcept_t;
+
+
+/* Type representing floating-point environment.  This structure
+   corresponds to the layout of the block written by the `fstenv'
+   instruction and has additional fields for the contents of the MXCSR
+   register as written by the `stmxcsr' instruction.  */
+typedef struct
+  {
+    unsigned short int __control_word;
+    unsigned short int __glibc_reserved1;
+    unsigned short int __status_word;
+    unsigned short int __glibc_reserved2;
+    unsigned short int __tags;
+    unsigned short int __glibc_reserved3;
+    unsigned int __eip;
+    unsigned short int __cs_selector;
+    unsigned int __opcode:11;
+    unsigned int __glibc_reserved4:5;
+    unsigned int __data_offset;
+    unsigned short int __data_selector;
+    unsigned short int __glibc_reserved5;
+#ifdef __x86_64__
+    unsigned int __mxcsr;
+#endif
+  }
+fenv_t;
+
+/* If the default argument is used we use this value.  */
+#define FE_DFL_ENV	((const fenv_t *) -1)
+
+#ifdef __USE_GNU
+/* Floating-point environment where none of the exception is masked.  */
+# define FE_NOMASK_ENV	((const fenv_t *) -2)
+#endif
+
+#if __GLIBC_USE (IEC_60559_BFP_EXT_C2X)
+/* Type representing floating-point control modes.  */
+typedef struct
+  {
+    unsigned short int __control_word;
+    unsigned short int __glibc_reserved;
+    unsigned int __mxcsr;
+  }
+femode_t;
+
+/* Default floating-point control modes.  */
+# define FE_DFL_MODE	((const femode_t *) -1L)
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@fenv.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@fenv.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@floatn-common.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@floatn-common.h
new file mode 100644
index 0000000000000000000000000000000000000000..92982d64601bc562733ffd64f9e88854407c16c7
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@floatn-common.h
@@ -0,0 +1,329 @@
+/* Macros to control TS 18661-3 glibc features where the same
+   definitions are appropriate for all platforms.
+   Copyright (C) 2017-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _BITS_FLOATN_COMMON_H
+#define _BITS_FLOATN_COMMON_H
+
+#include <features.h>
+#include <bits/long-double.h>
+
+/* This header should be included at the bottom of each bits/floatn.h.
+   It defines the following macros for each _FloatN and _FloatNx type,
+   where the same definitions, or definitions based only on the macros
+   in bits/floatn.h, are appropriate for all glibc configurations.  */
+
+/* Defined to 1 if the current compiler invocation provides a
+   floating-point type with the right format for this type, and this
+   glibc includes corresponding *fN or *fNx interfaces for it.  */
+#define __HAVE_FLOAT16 0
+#define __HAVE_FLOAT32 1
+#define __HAVE_FLOAT64 1
+#define __HAVE_FLOAT32X 1
+#define __HAVE_FLOAT128X 0
+
+/* Defined to 1 if the corresponding __HAVE_<type> macro is 1 and the
+   type is the first with its format in the sequence of (the default
+   choices for) float, double, long double, _Float16, _Float32,
+   _Float64, _Float128, _Float32x, _Float64x, _Float128x for this
+   glibc; that is, if functions present once per floating-point format
+   rather than once per type are present for this type.
+
+   All configurations supported by glibc have _Float32 the same format
+   as float, _Float64 and _Float32x the same format as double, the
+   _Float64x the same format as either long double or _Float128.  No
+   configurations support _Float128x or, as of GCC 7, have compiler
+   support for a type meeting the requirements for _Float128x.  */
+#define __HAVE_DISTINCT_FLOAT16 __HAVE_FLOAT16
+#define __HAVE_DISTINCT_FLOAT32 0
+#define __HAVE_DISTINCT_FLOAT64 0
+#define __HAVE_DISTINCT_FLOAT32X 0
+#define __HAVE_DISTINCT_FLOAT64X 0
+#define __HAVE_DISTINCT_FLOAT128X __HAVE_FLOAT128X
+
+/* Defined to 1 if the corresponding _FloatN type is not binary compatible
+   with the corresponding ISO C type in the current compilation unit as
+   opposed to __HAVE_DISTINCT_FLOATN, which indicates the default types built
+   in glibc.  */
+#define __HAVE_FLOAT128_UNLIKE_LDBL (__HAVE_DISTINCT_FLOAT128	\
+				     && __LDBL_MANT_DIG__ != 113)
+
+/* Defined to 1 if any _FloatN or _FloatNx types that are not
+   ABI-distinct are however distinct types at the C language level (so
+   for the purposes of __builtin_types_compatible_p and _Generic).  */
+#if __GNUC_PREREQ (7, 0) && !defined __cplusplus
+# define __HAVE_FLOATN_NOT_TYPEDEF 1
+#else
+# define __HAVE_FLOATN_NOT_TYPEDEF 0
+#endif
+
+#ifndef __ASSEMBLER__
+
+/* Defined to concatenate the literal suffix to be used with _FloatN
+   or _FloatNx types, if __HAVE_<type> is 1.  The corresponding
+   literal suffixes exist since GCC 7, for C only.  */
+# if __HAVE_FLOAT16
+#  if !__GNUC_PREREQ (7, 0) || defined __cplusplus
+/* No corresponding suffix available for this type.  */
+#   define __f16(x) ((_Float16) x##f)
+#  else
+#   define __f16(x) x##f16
+#  endif
+# endif
+
+# if __HAVE_FLOAT32
+#  if !__GNUC_PREREQ (7, 0) || defined __cplusplus
+#   define __f32(x) x##f
+#  else
+#   define __f32(x) x##f32
+#  endif
+# endif
+
+# if __HAVE_FLOAT64
+#  if !__GNUC_PREREQ (7, 0) || defined __cplusplus
+#   ifdef __NO_LONG_DOUBLE_MATH
+#    define __f64(x) x##l
+#   else
+#    define __f64(x) x
+#   endif
+#  else
+#   define __f64(x) x##f64
+#  endif
+# endif
+
+# if __HAVE_FLOAT32X
+#  if !__GNUC_PREREQ (7, 0) || defined __cplusplus
+#   define __f32x(x) x
+#  else
+#   define __f32x(x) x##f32x
+#  endif
+# endif
+
+# if __HAVE_FLOAT64X
+#  if !__GNUC_PREREQ (7, 0) || defined __cplusplus
+#   if __HAVE_FLOAT64X_LONG_DOUBLE
+#    define __f64x(x) x##l
+#   else
+#    define __f64x(x) __f128 (x)
+#   endif
+#  else
+#   define __f64x(x) x##f64x
+#  endif
+# endif
+
+# if __HAVE_FLOAT128X
+#  if !__GNUC_PREREQ (7, 0) || defined __cplusplus
+#   error "_Float128X supported but no constant suffix"
+#  else
+#   define __f128x(x) x##f128x
+#  endif
+# endif
+
+/* Defined to a complex type if __HAVE_<type> is 1.  */
+# if __HAVE_FLOAT16
+#  if !__GNUC_PREREQ (7, 0) || defined __cplusplus
+typedef _Complex float __cfloat16 __attribute__ ((__mode__ (__HC__)));
+#   define __CFLOAT16 __cfloat16
+#  else
+#   define __CFLOAT16 _Complex _Float16
+#  endif
+# endif
+
+# if __HAVE_FLOAT32
+#  if !__GNUC_PREREQ (7, 0) || defined __cplusplus
+#   define __CFLOAT32 _Complex float
+#  else
+#   define __CFLOAT32 _Complex _Float32
+#  endif
+# endif
+
+# if __HAVE_FLOAT64
+#  if !__GNUC_PREREQ (7, 0) || defined __cplusplus
+#   ifdef __NO_LONG_DOUBLE_MATH
+#    define __CFLOAT64 _Complex long double
+#   else
+#    define __CFLOAT64 _Complex double
+#   endif
+#  else
+#   define __CFLOAT64 _Complex _Float64
+#  endif
+# endif
+
+# if __HAVE_FLOAT32X
+#  if !__GNUC_PREREQ (7, 0) || defined __cplusplus
+#   define __CFLOAT32X _Complex double
+#  else
+#   define __CFLOAT32X _Complex _Float32x
+#  endif
+# endif
+
+# if __HAVE_FLOAT64X
+#  if !__GNUC_PREREQ (7, 0) || defined __cplusplus
+#   if __HAVE_FLOAT64X_LONG_DOUBLE
+#    define __CFLOAT64X _Complex long double
+#   else
+#    define __CFLOAT64X __CFLOAT128
+#   endif
+#  else
+#   define __CFLOAT64X _Complex _Float64x
+#  endif
+# endif
+
+# if __HAVE_FLOAT128X
+#  if !__GNUC_PREREQ (7, 0) || defined __cplusplus
+#   error "_Float128X supported but no complex type"
+#  else
+#   define __CFLOAT128X _Complex _Float128x
+#  endif
+# endif
+
+/* The remaining of this file provides support for older compilers.  */
+# if __HAVE_FLOAT16
+
+#  if !__GNUC_PREREQ (7, 0) || defined __cplusplus
+typedef float _Float16 __attribute__ ((__mode__ (__HF__)));
+#  endif
+
+#  if !__GNUC_PREREQ (7, 0)
+#   define __builtin_huge_valf16() ((_Float16) __builtin_huge_val ())
+#   define __builtin_inff16() ((_Float16) __builtin_inf ())
+#   define __builtin_nanf16(x) ((_Float16) __builtin_nan (x))
+#   define __builtin_nansf16(x) ((_Float16) __builtin_nans (x))
+#  endif
+
+# endif
+
+# if __HAVE_FLOAT32
+
+#  if !__GNUC_PREREQ (7, 0) || defined __cplusplus
+typedef float _Float32;
+#  endif
+
+#  if !__GNUC_PREREQ (7, 0)
+#   define __builtin_huge_valf32() (__builtin_huge_valf ())
+#   define __builtin_inff32() (__builtin_inff ())
+#   define __builtin_nanf32(x) (__builtin_nanf (x))
+#   define __builtin_nansf32(x) (__builtin_nansf (x))
+#  endif
+
+# endif
+
+# if __HAVE_FLOAT64
+
+/* If double, long double and _Float64 all have the same set of
+   values, TS 18661-3 requires the usual arithmetic conversions on
+   long double and _Float64 to produce _Float64.  For this to be the
+   case when building with a compiler without a distinct _Float64
+   type, _Float64 must be a typedef for long double, not for
+   double.  */
+
+#  ifdef __NO_LONG_DOUBLE_MATH
+
+#   if !__GNUC_PREREQ (7, 0) || defined __cplusplus
+typedef long double _Float64;
+#   endif
+
+#   if !__GNUC_PREREQ (7, 0)
+#    define __builtin_huge_valf64() (__builtin_huge_vall ())
+#    define __builtin_inff64() (__builtin_infl ())
+#    define __builtin_nanf64(x) (__builtin_nanl (x))
+#    define __builtin_nansf64(x) (__builtin_nansl (x))
+#   endif
+
+#  else
+
+#   if !__GNUC_PREREQ (7, 0) || defined __cplusplus
+typedef double _Float64;
+#   endif
+
+#   if !__GNUC_PREREQ (7, 0)
+#    define __builtin_huge_valf64() (__builtin_huge_val ())
+#    define __builtin_inff64() (__builtin_inf ())
+#    define __builtin_nanf64(x) (__builtin_nan (x))
+#    define __builtin_nansf64(x) (__builtin_nans (x))
+#   endif
+
+#  endif
+
+# endif
+
+# if __HAVE_FLOAT32X
+
+#  if !__GNUC_PREREQ (7, 0) || defined __cplusplus
+typedef double _Float32x;
+#  endif
+
+#  if !__GNUC_PREREQ (7, 0)
+#   define __builtin_huge_valf32x() (__builtin_huge_val ())
+#   define __builtin_inff32x() (__builtin_inf ())
+#   define __builtin_nanf32x(x) (__builtin_nan (x))
+#   define __builtin_nansf32x(x) (__builtin_nans (x))
+#  endif
+
+# endif
+
+# if __HAVE_FLOAT64X
+
+#  if __HAVE_FLOAT64X_LONG_DOUBLE
+
+#   if !__GNUC_PREREQ (7, 0) || defined __cplusplus
+typedef long double _Float64x;
+#   endif
+
+#   if !__GNUC_PREREQ (7, 0)
+#    define __builtin_huge_valf64x() (__builtin_huge_vall ())
+#    define __builtin_inff64x() (__builtin_infl ())
+#    define __builtin_nanf64x(x) (__builtin_nanl (x))
+#    define __builtin_nansf64x(x) (__builtin_nansl (x))
+#   endif
+
+#  else
+
+#   if !__GNUC_PREREQ (7, 0) || defined __cplusplus
+typedef _Float128 _Float64x;
+#   endif
+
+#   if !__GNUC_PREREQ (7, 0)
+#    define __builtin_huge_valf64x() (__builtin_huge_valf128 ())
+#    define __builtin_inff64x() (__builtin_inff128 ())
+#    define __builtin_nanf64x(x) (__builtin_nanf128 (x))
+#    define __builtin_nansf64x(x) (__builtin_nansf128 (x))
+#   endif
+
+#  endif
+
+# endif
+
+# if __HAVE_FLOAT128X
+
+#  if !__GNUC_PREREQ (7, 0) || defined __cplusplus
+#   error "_Float128x supported but no type"
+#  endif
+
+#  if !__GNUC_PREREQ (7, 0)
+#   define __builtin_huge_valf128x() ((_Float128x) __builtin_huge_val ())
+#   define __builtin_inff128x() ((_Float128x) __builtin_inf ())
+#   define __builtin_nanf128x(x) ((_Float128x) __builtin_nan (x))
+#   define __builtin_nansf128x(x) ((_Float128x) __builtin_nans (x))
+#  endif
+
+# endif
+
+#endif /* !__ASSEMBLER__.  */
+
+#endif /* _BITS_FLOATN_COMMON_H */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@floatn-common.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@floatn-common.h.blob
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@floatn.h
@@ -0,0 +1,121 @@
+/* Macros to control TS 18661-3 glibc features on x86.
+   Copyright (C) 2017-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _BITS_FLOATN_H
+#define _BITS_FLOATN_H
+
+#include <features.h>
+
+/* Defined to 1 if the current compiler invocation provides a
+   floating-point type with the IEEE 754 binary128 format, and this
+   glibc includes corresponding *f128 interfaces for it.  The required
+   libgcc support was added some time after the basic compiler
+   support, for x86_64 and x86.  */
+#if (defined __x86_64__							\
+     ? __GNUC_PREREQ (4, 3)						\
+     : (defined __GNU__ ? __GNUC_PREREQ (4, 5) : __GNUC_PREREQ (4, 4)))
+# define __HAVE_FLOAT128 1
+#else
+# define __HAVE_FLOAT128 0
+#endif
+
+/* Defined to 1 if __HAVE_FLOAT128 is 1 and the type is ABI-distinct
+   from the default float, double and long double types in this glibc.  */
+#if __HAVE_FLOAT128
+# define __HAVE_DISTINCT_FLOAT128 1
+#else
+# define __HAVE_DISTINCT_FLOAT128 0
+#endif
+
+/* Defined to 1 if the current compiler invocation provides a
+   floating-point type with the right format for _Float64x, and this
+   glibc includes corresponding *f64x interfaces for it.  */
+#define __HAVE_FLOAT64X 1
+
+/* Defined to 1 if __HAVE_FLOAT64X is 1 and _Float64x has the format
+   of long double.  Otherwise, if __HAVE_FLOAT64X is 1, _Float64x has
+   the format of _Float128, which must be different from that of long
+   double.  */
+#define __HAVE_FLOAT64X_LONG_DOUBLE 1
+
+#ifndef __ASSEMBLER__
+
+/* Defined to concatenate the literal suffix to be used with _Float128
+   types, if __HAVE_FLOAT128 is 1. */
+# if __HAVE_FLOAT128
+#  if !__GNUC_PREREQ (7, 0) || defined __cplusplus
+/* The literal suffix f128 exists only since GCC 7.0.  */
+#   define __f128(x) x##q
+#  else
+#   define __f128(x) x##f128
+#  endif
+# endif
+
+/* Defined to a complex binary128 type if __HAVE_FLOAT128 is 1.  */
+# if __HAVE_FLOAT128
+#  if !__GNUC_PREREQ (7, 0) || defined __cplusplus
+/* Add a typedef for older GCC compilers which don't natively support
+   _Complex _Float128.  */
+typedef _Complex float __cfloat128 __attribute__ ((__mode__ (__TC__)));
+#   define __CFLOAT128 __cfloat128
+#  else
+#   define __CFLOAT128 _Complex _Float128
+#  endif
+# endif
+
+/* The remaining of this file provides support for older compilers.  */
+# if __HAVE_FLOAT128
+
+/* The type _Float128 exists only since GCC 7.0.  */
+#  if !__GNUC_PREREQ (7, 0) || defined __cplusplus
+typedef __float128 _Float128;
+#  endif
+
+/* __builtin_huge_valf128 doesn't exist before GCC 7.0.  */
+#  if !__GNUC_PREREQ (7, 0)
+#   define __builtin_huge_valf128() ((_Float128) __builtin_huge_val ())
+#  endif
+
+/* Older GCC has only a subset of built-in functions for _Float128 on
+   x86, and __builtin_infq is not usable in static initializers.
+   Converting a narrower sNaN to _Float128 produces a quiet NaN, so
+   attempts to use _Float128 sNaNs will not work properly with older
+   compilers.  */
+#  if !__GNUC_PREREQ (7, 0)
+#   define __builtin_copysignf128 __builtin_copysignq
+#   define __builtin_fabsf128 __builtin_fabsq
+#   define __builtin_inff128() ((_Float128) __builtin_inf ())
+#   define __builtin_nanf128(x) ((_Float128) __builtin_nan (x))
+#   define __builtin_nansf128(x) ((_Float128) __builtin_nans (x))
+#  endif
+
+/* In math/math.h, __MATH_TG will expand signbit to __builtin_signbit*,
+   e.g.: __builtin_signbitf128, before GCC 6.  However, there has never
+   been a __builtin_signbitf128 in GCC and the type-generic builtin is
+   only available since GCC 6.  */
+#  if !__GNUC_PREREQ (6, 0)
+#   define __builtin_signbitf128 __signbitf128
+#  endif
+
+# endif
+
+#endif /* !__ASSEMBLER__.  */
+
+#include <bits/floatn-common.h>
+
+#endif /* _BITS_FLOATN_H */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@floatn.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@floatn.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@flt-eval-method.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@flt-eval-method.h
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--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@flt-eval-method.h
@@ -0,0 +1,33 @@
+/* Define __GLIBC_FLT_EVAL_METHOD.  x86 version.
+   Copyright (C) 2016-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _MATH_H
+# error "Never use <bits/flt-eval-method.h> directly; include <math.h> instead."
+#endif
+
+#ifdef __FLT_EVAL_METHOD__
+# if __FLT_EVAL_METHOD__ == -1
+#  define __GLIBC_FLT_EVAL_METHOD	2
+# else
+#  define __GLIBC_FLT_EVAL_METHOD	__FLT_EVAL_METHOD__
+# endif
+#elif defined __x86_64__
+# define __GLIBC_FLT_EVAL_METHOD	0
+#else
+# define __GLIBC_FLT_EVAL_METHOD	2
+#endif
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@fp-fast.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@fp-fast.h
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--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@fp-fast.h
@@ -0,0 +1,39 @@
+/* Define FP_FAST_* macros.
+   Copyright (C) 2016-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _MATH_H
+# error "Never use <bits/fp-fast.h> directly; include <math.h> instead."
+#endif
+
+#ifdef __USE_ISOC99
+
+/* The GCC 4.6 compiler will define __FP_FAST_FMA{,F,L} if the fma{,f,l}
+   builtins are supported.  */
+# ifdef __FP_FAST_FMA
+#  define FP_FAST_FMA 1
+# endif
+
+# ifdef __FP_FAST_FMAF
+#  define FP_FAST_FMAF 1
+# endif
+
+# ifdef __FP_FAST_FMAL
+#  define FP_FAST_FMAL 1
+# endif
+
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@fp-fast.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@fp-fast.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@fp-logb.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@fp-logb.h
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@@ -0,0 +1,24 @@
+/* Define __FP_LOGB0_IS_MIN and __FP_LOGBNAN_IS_MIN.  x86 version.
+   Copyright (C) 2016-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _MATH_H
+# error "Never use <bits/fp-logb.h> directly; include <math.h> instead."
+#endif
+
+#define __FP_LOGB0_IS_MIN	1
+#define __FP_LOGBNAN_IS_MIN	1
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@getopt_core.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@getopt_core.h
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@getopt_core.h
@@ -0,0 +1,96 @@
+/* Declarations for getopt (basic, portable features only).
+   Copyright (C) 1989-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library and is also part of gnulib.
+   Patches to this file should be submitted to both projects.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _GETOPT_CORE_H
+#define _GETOPT_CORE_H 1
+
+/* This header should not be used directly; include getopt.h or
+   unistd.h instead.  Unlike most bits headers, it does not have
+   a protective #error, because the guard macro for getopt.h in
+   gnulib is not fixed.  */
+
+__BEGIN_DECLS
+
+/* For communication from 'getopt' to the caller.
+   When 'getopt' finds an option that takes an argument,
+   the argument value is returned here.
+   Also, when 'ordering' is RETURN_IN_ORDER,
+   each non-option ARGV-element is returned here.  */
+
+extern char *optarg;
+
+/* Index in ARGV of the next element to be scanned.
+   This is used for communication to and from the caller
+   and for communication between successive calls to 'getopt'.
+
+   On entry to 'getopt', zero means this is the first call; initialize.
+
+   When 'getopt' returns -1, this is the index of the first of the
+   non-option elements that the caller should itself scan.
+
+   Otherwise, 'optind' communicates from one call to the next
+   how much of ARGV has been scanned so far.  */
+
+extern int optind;
+
+/* Callers store zero here to inhibit the error message 'getopt' prints
+   for unrecognized options.  */
+
+extern int opterr;
+
+/* Set to an option character which was unrecognized.  */
+
+extern int optopt;
+
+/* Get definitions and prototypes for functions to process the
+   arguments in ARGV (ARGC of them, minus the program name) for
+   options given in OPTS.
+
+   Return the option character from OPTS just read.  Return -1 when
+   there are no more options.  For unrecognized options, or options
+   missing arguments, 'optopt' is set to the option letter, and '?' is
+   returned.
+
+   The OPTS string is a list of characters which are recognized option
+   letters, optionally followed by colons, specifying that that letter
+   takes an argument, to be placed in 'optarg'.
+
+   If a letter in OPTS is followed by two colons, its argument is
+   optional.  This behavior is specific to the GNU 'getopt'.
+
+   The argument '--' causes premature termination of argument
+   scanning, explicitly telling 'getopt' that there are no more
+   options.
+
+   If OPTS begins with '-', then non-option arguments are treated as
+   arguments to the option '\1'.  This behavior is specific to the GNU
+   'getopt'.  If OPTS begins with '+', or POSIXLY_CORRECT is set in
+   the environment, then do not permute arguments.
+
+   For standards compliance, the 'argv' argument has the type
+   char *const *, but this is inaccurate; if argument permutation is
+   enabled, the argv array (not the strings it points to) must be
+   writable.  */
+
+extern int getopt (int ___argc, char *const *___argv, const char *__shortopts)
+       __THROW __nonnull ((2, 3));
+
+__END_DECLS
+
+#endif /* getopt_core.h */
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@getopt_posix.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@getopt_posix.h
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@@ -0,0 +1,51 @@
+/* Declarations for getopt (POSIX compatibility shim).
+   Copyright (C) 1989-2022 Free Software Foundation, Inc.
+   Unlike the bulk of the getopt implementation, this file is NOT part
+   of gnulib.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _GETOPT_POSIX_H
+#define _GETOPT_POSIX_H 1
+
+#if !defined _UNISTD_H && !defined _STDIO_H
+#error "Never include getopt_posix.h directly; use unistd.h instead."
+#endif
+
+#include <bits/getopt_core.h>
+
+__BEGIN_DECLS
+
+#if defined __USE_POSIX2 && !defined __USE_POSIX_IMPLICITLY \
+    && !defined __USE_GNU && !defined _GETOPT_H
+/* GNU getopt has more functionality than POSIX getopt.  When we are
+   explicitly conforming to POSIX and not GNU, and getopt.h (which is
+   not part of POSIX) has not been included, the extra functionality
+   is disabled.  */
+# ifdef __REDIRECT
+extern int __REDIRECT_NTH (getopt, (int ___argc, char *const *___argv,
+				    const char *__shortopts),
+			   __posix_getopt);
+# else
+extern int __posix_getopt (int ___argc, char *const *___argv,
+			   const char *__shortopts)
+  __THROW __nonnull ((2, 3));
+#  define getopt __posix_getopt
+# endif
+#endif
+
+__END_DECLS
+
+#endif /* getopt_posix.h */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@getopt_posix.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@getopt_posix.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@iscanonical.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@iscanonical.h
new file mode 100644
index 0000000000000000000000000000000000000000..790d6a12e34eb034d9e3b4b13c8f42b95d9c00ee
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@iscanonical.h
@@ -0,0 +1,54 @@
+/* Define iscanonical macro.  ldbl-96 version.
+   Copyright (C) 2016-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _MATH_H
+# error "Never use <bits/iscanonical.h> directly; include <math.h> instead."
+#endif
+
+extern int __iscanonicall (long double __x)
+     __THROW __attribute__ ((__const__));
+#define __iscanonicalf(x) ((void) (__typeof (x)) (x), 1)
+#define __iscanonical(x) ((void) (__typeof (x)) (x), 1)
+#if __HAVE_DISTINCT_FLOAT128
+# define __iscanonicalf128(x) ((void) (__typeof (x)) (x), 1)
+#endif
+
+/* Return nonzero value if X is canonical.  In IEEE interchange binary
+   formats, all values are canonical, but the argument must still be
+   converted to its semantic type for any exceptions arising from the
+   conversion, before being discarded; in extended precision, there
+   are encodings that are not consistently handled as corresponding to
+   any particular value of the type, and we return 0 for those.  */
+#ifndef __cplusplus
+# define iscanonical(x) __MATH_TG ((x), __iscanonical, (x))
+#else
+/* In C++ mode, __MATH_TG cannot be used, because it relies on
+   __builtin_types_compatible_p, which is a C-only builtin.  On the
+   other hand, overloading provides the means to distinguish between
+   the floating-point types.  The overloading resolution will match
+   the correct parameter (regardless of type qualifiers (i.e.: const
+   and volatile)).  */
+extern "C++" {
+inline int iscanonical (float __val) { return __iscanonicalf (__val); }
+inline int iscanonical (double __val) { return __iscanonical (__val); }
+inline int iscanonical (long double __val) { return __iscanonicall (__val); }
+# if __HAVE_DISTINCT_FLOAT128
+inline int iscanonical (_Float128 __val) { return __iscanonicalf128 (__val); }
+# endif
+}
+#endif /* __cplusplus */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@iscanonical.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@iscanonical.h.blob
new file mode 100644
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@libc-header-start.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@libc-header-start.h
new file mode 100644
index 0000000000000000000000000000000000000000..d161ca50fc249e256c107945bda848ba87dde407
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@libc-header-start.h
@@ -0,0 +1,110 @@
+/* Handle feature test macros at the start of a header.
+   Copyright (C) 2016-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+/* This header is internal to glibc and should not be included outside
+   of glibc headers.  Headers including it must define
+   __GLIBC_INTERNAL_STARTING_HEADER_IMPLEMENTATION first.  This header
+   cannot have multiple include guards because ISO C feature test
+   macros depend on the definition of the macro when an affected
+   header is included, not when the first system header is
+   included.  */
+
+#ifndef __GLIBC_INTERNAL_STARTING_HEADER_IMPLEMENTATION
+# error "Never include <bits/libc-header-start.h> directly."
+#endif
+
+#undef __GLIBC_INTERNAL_STARTING_HEADER_IMPLEMENTATION
+
+#include <features.h>
+
+/* ISO/IEC TR 24731-2:2010 defines the __STDC_WANT_LIB_EXT2__
+   macro.  */
+#undef __GLIBC_USE_LIB_EXT2
+#if (defined __USE_GNU							\
+     || (defined __STDC_WANT_LIB_EXT2__ && __STDC_WANT_LIB_EXT2__ > 0))
+# define __GLIBC_USE_LIB_EXT2 1
+#else
+# define __GLIBC_USE_LIB_EXT2 0
+#endif
+
+/* ISO/IEC TS 18661-1:2014 defines the __STDC_WANT_IEC_60559_BFP_EXT__
+   macro.  Most but not all symbols enabled by that macro in TS
+   18661-1 are enabled unconditionally in C2X.  In C2X, the symbols in
+   Annex F still require a new feature test macro
+   __STDC_WANT_IEC_60559_EXT__ instead (C2X does not define
+   __STDC_WANT_IEC_60559_BFP_EXT__), while a few features from TS
+   18661-1 are not included in C2X (and thus should depend on
+   __STDC_WANT_IEC_60559_BFP_EXT__ even when C2X features are
+   enabled).
+
+   __GLIBC_USE (IEC_60559_BFP_EXT) controls those features from TS
+   18661-1 not included in C2X.
+
+   __GLIBC_USE (IEC_60559_BFP_EXT_C2X) controls those features from TS
+   18661-1 that are also included in C2X (with no feature test macro
+   required in C2X).
+
+   __GLIBC_USE (IEC_60559_EXT) controls those features from TS 18661-1
+   that are included in C2X but conditional on
+   __STDC_WANT_IEC_60559_EXT__.  (There are currently no features
+   conditional on __STDC_WANT_IEC_60559_EXT__ that are not in TS
+   18661-1.)  */
+#undef __GLIBC_USE_IEC_60559_BFP_EXT
+#if defined __USE_GNU || defined __STDC_WANT_IEC_60559_BFP_EXT__
+# define __GLIBC_USE_IEC_60559_BFP_EXT 1
+#else
+# define __GLIBC_USE_IEC_60559_BFP_EXT 0
+#endif
+#undef __GLIBC_USE_IEC_60559_BFP_EXT_C2X
+#if __GLIBC_USE (IEC_60559_BFP_EXT) || __GLIBC_USE (ISOC2X)
+# define __GLIBC_USE_IEC_60559_BFP_EXT_C2X 1
+#else
+# define __GLIBC_USE_IEC_60559_BFP_EXT_C2X 0
+#endif
+#undef __GLIBC_USE_IEC_60559_EXT
+#if __GLIBC_USE (IEC_60559_BFP_EXT) || defined __STDC_WANT_IEC_60559_EXT__
+# define __GLIBC_USE_IEC_60559_EXT 1
+#else
+# define __GLIBC_USE_IEC_60559_EXT 0
+#endif
+
+/* ISO/IEC TS 18661-4:2015 defines the
+   __STDC_WANT_IEC_60559_FUNCS_EXT__ macro.  Other than the reduction
+   functions, the symbols from this TS are enabled unconditionally in
+   C2X.  */
+#undef __GLIBC_USE_IEC_60559_FUNCS_EXT
+#if defined __USE_GNU || defined __STDC_WANT_IEC_60559_FUNCS_EXT__
+# define __GLIBC_USE_IEC_60559_FUNCS_EXT 1
+#else
+# define __GLIBC_USE_IEC_60559_FUNCS_EXT 0
+#endif
+#undef __GLIBC_USE_IEC_60559_FUNCS_EXT_C2X
+#if __GLIBC_USE (IEC_60559_FUNCS_EXT) || __GLIBC_USE (ISOC2X)
+# define __GLIBC_USE_IEC_60559_FUNCS_EXT_C2X 1
+#else
+# define __GLIBC_USE_IEC_60559_FUNCS_EXT_C2X 0
+#endif
+
+/* ISO/IEC TS 18661-3:2015 defines the
+   __STDC_WANT_IEC_60559_TYPES_EXT__ macro.  */
+#undef __GLIBC_USE_IEC_60559_TYPES_EXT
+#if defined __USE_GNU || defined __STDC_WANT_IEC_60559_TYPES_EXT__
+# define __GLIBC_USE_IEC_60559_TYPES_EXT 1
+#else
+# define __GLIBC_USE_IEC_60559_TYPES_EXT 0
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@libc-header-start.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@libc-header-start.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@libm-simd-decl-stubs.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@libm-simd-decl-stubs.h
new file mode 100644
index 0000000000000000000000000000000000000000..200d7369b96fbd9a461c0931085ccfcd16266dc4
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@libm-simd-decl-stubs.h
@@ -0,0 +1,332 @@
+/* Empty definitions required for __MATHCALL_VEC unfolding in mathcalls.h.
+   Copyright (C) 2014-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _MATH_H
+# error "Never include <bits/libm-simd-decl-stubs.h> directly;\
+ include <math.h> instead."
+#endif
+
+/* Needed definitions could be generated with:
+   for func in $(grep __MATHCALL_VEC math/bits/mathcalls.h |\
+		 sed -r "s|__MATHCALL_VEC.?\(||; s|,.*||"); do
+     echo "#define __DECL_SIMD_${func}";
+     echo "#define __DECL_SIMD_${func}f";
+     echo "#define __DECL_SIMD_${func}l";
+   done
+ */
+
+#ifndef _BITS_LIBM_SIMD_DECL_STUBS_H
+#define _BITS_LIBM_SIMD_DECL_STUBS_H 1
+
+#define __DECL_SIMD_cos
+#define __DECL_SIMD_cosf
+#define __DECL_SIMD_cosl
+#define __DECL_SIMD_cosf16
+#define __DECL_SIMD_cosf32
+#define __DECL_SIMD_cosf64
+#define __DECL_SIMD_cosf128
+#define __DECL_SIMD_cosf32x
+#define __DECL_SIMD_cosf64x
+#define __DECL_SIMD_cosf128x
+
+#define __DECL_SIMD_sin
+#define __DECL_SIMD_sinf
+#define __DECL_SIMD_sinl
+#define __DECL_SIMD_sinf16
+#define __DECL_SIMD_sinf32
+#define __DECL_SIMD_sinf64
+#define __DECL_SIMD_sinf128
+#define __DECL_SIMD_sinf32x
+#define __DECL_SIMD_sinf64x
+#define __DECL_SIMD_sinf128x
+
+#define __DECL_SIMD_sincos
+#define __DECL_SIMD_sincosf
+#define __DECL_SIMD_sincosl
+#define __DECL_SIMD_sincosf16
+#define __DECL_SIMD_sincosf32
+#define __DECL_SIMD_sincosf64
+#define __DECL_SIMD_sincosf128
+#define __DECL_SIMD_sincosf32x
+#define __DECL_SIMD_sincosf64x
+#define __DECL_SIMD_sincosf128x
+
+#define __DECL_SIMD_log
+#define __DECL_SIMD_logf
+#define __DECL_SIMD_logl
+#define __DECL_SIMD_logf16
+#define __DECL_SIMD_logf32
+#define __DECL_SIMD_logf64
+#define __DECL_SIMD_logf128
+#define __DECL_SIMD_logf32x
+#define __DECL_SIMD_logf64x
+#define __DECL_SIMD_logf128x
+
+#define __DECL_SIMD_exp
+#define __DECL_SIMD_expf
+#define __DECL_SIMD_expl
+#define __DECL_SIMD_expf16
+#define __DECL_SIMD_expf32
+#define __DECL_SIMD_expf64
+#define __DECL_SIMD_expf128
+#define __DECL_SIMD_expf32x
+#define __DECL_SIMD_expf64x
+#define __DECL_SIMD_expf128x
+
+#define __DECL_SIMD_pow
+#define __DECL_SIMD_powf
+#define __DECL_SIMD_powl
+#define __DECL_SIMD_powf16
+#define __DECL_SIMD_powf32
+#define __DECL_SIMD_powf64
+#define __DECL_SIMD_powf128
+#define __DECL_SIMD_powf32x
+#define __DECL_SIMD_powf64x
+#define __DECL_SIMD_powf128x
+
+#define __DECL_SIMD_acos
+#define __DECL_SIMD_acosf
+#define __DECL_SIMD_acosl
+#define __DECL_SIMD_acosf16
+#define __DECL_SIMD_acosf32
+#define __DECL_SIMD_acosf64
+#define __DECL_SIMD_acosf128
+#define __DECL_SIMD_acosf32x
+#define __DECL_SIMD_acosf64x
+#define __DECL_SIMD_acosf128x
+
+#define __DECL_SIMD_atan
+#define __DECL_SIMD_atanf
+#define __DECL_SIMD_atanl
+#define __DECL_SIMD_atanf16
+#define __DECL_SIMD_atanf32
+#define __DECL_SIMD_atanf64
+#define __DECL_SIMD_atanf128
+#define __DECL_SIMD_atanf32x
+#define __DECL_SIMD_atanf64x
+#define __DECL_SIMD_atanf128x
+
+#define __DECL_SIMD_asin
+#define __DECL_SIMD_asinf
+#define __DECL_SIMD_asinl
+#define __DECL_SIMD_asinf16
+#define __DECL_SIMD_asinf32
+#define __DECL_SIMD_asinf64
+#define __DECL_SIMD_asinf128
+#define __DECL_SIMD_asinf32x
+#define __DECL_SIMD_asinf64x
+#define __DECL_SIMD_asinf128x
+
+#define __DECL_SIMD_hypot
+#define __DECL_SIMD_hypotf
+#define __DECL_SIMD_hypotl
+#define __DECL_SIMD_hypotf16
+#define __DECL_SIMD_hypotf32
+#define __DECL_SIMD_hypotf64
+#define __DECL_SIMD_hypotf128
+#define __DECL_SIMD_hypotf32x
+#define __DECL_SIMD_hypotf64x
+#define __DECL_SIMD_hypotf128x
+
+#define __DECL_SIMD_exp2
+#define __DECL_SIMD_exp2f
+#define __DECL_SIMD_exp2l
+#define __DECL_SIMD_exp2f16
+#define __DECL_SIMD_exp2f32
+#define __DECL_SIMD_exp2f64
+#define __DECL_SIMD_exp2f128
+#define __DECL_SIMD_exp2f32x
+#define __DECL_SIMD_exp2f64x
+#define __DECL_SIMD_exp2f128x
+
+#define __DECL_SIMD_exp10
+#define __DECL_SIMD_exp10f
+#define __DECL_SIMD_exp10l
+#define __DECL_SIMD_exp10f16
+#define __DECL_SIMD_exp10f32
+#define __DECL_SIMD_exp10f64
+#define __DECL_SIMD_exp10f128
+#define __DECL_SIMD_exp10f32x
+#define __DECL_SIMD_exp10f64x
+#define __DECL_SIMD_exp10f128x
+
+#define __DECL_SIMD_cosh
+#define __DECL_SIMD_coshf
+#define __DECL_SIMD_coshl
+#define __DECL_SIMD_coshf16
+#define __DECL_SIMD_coshf32
+#define __DECL_SIMD_coshf64
+#define __DECL_SIMD_coshf128
+#define __DECL_SIMD_coshf32x
+#define __DECL_SIMD_coshf64x
+#define __DECL_SIMD_coshf128x
+
+#define __DECL_SIMD_expm1
+#define __DECL_SIMD_expm1f
+#define __DECL_SIMD_expm1l
+#define __DECL_SIMD_expm1f16
+#define __DECL_SIMD_expm1f32
+#define __DECL_SIMD_expm1f64
+#define __DECL_SIMD_expm1f128
+#define __DECL_SIMD_expm1f32x
+#define __DECL_SIMD_expm1f64x
+#define __DECL_SIMD_expm1f128x
+
+#define __DECL_SIMD_sinh
+#define __DECL_SIMD_sinhf
+#define __DECL_SIMD_sinhl
+#define __DECL_SIMD_sinhf16
+#define __DECL_SIMD_sinhf32
+#define __DECL_SIMD_sinhf64
+#define __DECL_SIMD_sinhf128
+#define __DECL_SIMD_sinhf32x
+#define __DECL_SIMD_sinhf64x
+#define __DECL_SIMD_sinhf128x
+
+#define __DECL_SIMD_cbrt
+#define __DECL_SIMD_cbrtf
+#define __DECL_SIMD_cbrtl
+#define __DECL_SIMD_cbrtf16
+#define __DECL_SIMD_cbrtf32
+#define __DECL_SIMD_cbrtf64
+#define __DECL_SIMD_cbrtf128
+#define __DECL_SIMD_cbrtf32x
+#define __DECL_SIMD_cbrtf64x
+#define __DECL_SIMD_cbrtf128x
+
+#define __DECL_SIMD_atan2
+#define __DECL_SIMD_atan2f
+#define __DECL_SIMD_atan2l
+#define __DECL_SIMD_atan2f16
+#define __DECL_SIMD_atan2f32
+#define __DECL_SIMD_atan2f64
+#define __DECL_SIMD_atan2f128
+#define __DECL_SIMD_atan2f32x
+#define __DECL_SIMD_atan2f64x
+#define __DECL_SIMD_atan2f128x
+
+#define __DECL_SIMD_log10
+#define __DECL_SIMD_log10f
+#define __DECL_SIMD_log10l
+#define __DECL_SIMD_log10f16
+#define __DECL_SIMD_log10f32
+#define __DECL_SIMD_log10f64
+#define __DECL_SIMD_log10f128
+#define __DECL_SIMD_log10f32x
+#define __DECL_SIMD_log10f64x
+#define __DECL_SIMD_log10f128x
+
+#define __DECL_SIMD_log2
+#define __DECL_SIMD_log2f
+#define __DECL_SIMD_log2l
+#define __DECL_SIMD_log2f16
+#define __DECL_SIMD_log2f32
+#define __DECL_SIMD_log2f64
+#define __DECL_SIMD_log2f128
+#define __DECL_SIMD_log2f32x
+#define __DECL_SIMD_log2f64x
+#define __DECL_SIMD_log2f128x
+
+#define __DECL_SIMD_log1p
+#define __DECL_SIMD_log1pf
+#define __DECL_SIMD_log1pl
+#define __DECL_SIMD_log1pf16
+#define __DECL_SIMD_log1pf32
+#define __DECL_SIMD_log1pf64
+#define __DECL_SIMD_log1pf128
+#define __DECL_SIMD_log1pf32x
+#define __DECL_SIMD_log1pf64x
+#define __DECL_SIMD_log1pf128x
+
+#define __DECL_SIMD_atanh
+#define __DECL_SIMD_atanhf
+#define __DECL_SIMD_atanhl
+#define __DECL_SIMD_atanhf16
+#define __DECL_SIMD_atanhf32
+#define __DECL_SIMD_atanhf64
+#define __DECL_SIMD_atanhf128
+#define __DECL_SIMD_atanhf32x
+#define __DECL_SIMD_atanhf64x
+#define __DECL_SIMD_atanhf128x
+
+#define __DECL_SIMD_acosh
+#define __DECL_SIMD_acoshf
+#define __DECL_SIMD_acoshl
+#define __DECL_SIMD_acoshf16
+#define __DECL_SIMD_acoshf32
+#define __DECL_SIMD_acoshf64
+#define __DECL_SIMD_acoshf128
+#define __DECL_SIMD_acoshf32x
+#define __DECL_SIMD_acoshf64x
+#define __DECL_SIMD_acoshf128x
+
+#define __DECL_SIMD_erf
+#define __DECL_SIMD_erff
+#define __DECL_SIMD_erfl
+#define __DECL_SIMD_erff16
+#define __DECL_SIMD_erff32
+#define __DECL_SIMD_erff64
+#define __DECL_SIMD_erff128
+#define __DECL_SIMD_erff32x
+#define __DECL_SIMD_erff64x
+#define __DECL_SIMD_erff128x
+
+#define __DECL_SIMD_tanh
+#define __DECL_SIMD_tanhf
+#define __DECL_SIMD_tanhl
+#define __DECL_SIMD_tanhf16
+#define __DECL_SIMD_tanhf32
+#define __DECL_SIMD_tanhf64
+#define __DECL_SIMD_tanhf128
+#define __DECL_SIMD_tanhf32x
+#define __DECL_SIMD_tanhf64x
+#define __DECL_SIMD_tanhf128x
+
+#define __DECL_SIMD_asinh
+#define __DECL_SIMD_asinhf
+#define __DECL_SIMD_asinhl
+#define __DECL_SIMD_asinhf16
+#define __DECL_SIMD_asinhf32
+#define __DECL_SIMD_asinhf64
+#define __DECL_SIMD_asinhf128
+#define __DECL_SIMD_asinhf32x
+#define __DECL_SIMD_asinhf64x
+#define __DECL_SIMD_asinhf128x
+
+#define __DECL_SIMD_erfc
+#define __DECL_SIMD_erfcf
+#define __DECL_SIMD_erfcl
+#define __DECL_SIMD_erfcf16
+#define __DECL_SIMD_erfcf32
+#define __DECL_SIMD_erfcf64
+#define __DECL_SIMD_erfcf128
+#define __DECL_SIMD_erfcf32x
+#define __DECL_SIMD_erfcf64x
+#define __DECL_SIMD_erfcf128x
+
+#define __DECL_SIMD_tan
+#define __DECL_SIMD_tanf
+#define __DECL_SIMD_tanl
+#define __DECL_SIMD_tanf16
+#define __DECL_SIMD_tanf32
+#define __DECL_SIMD_tanf64
+#define __DECL_SIMD_tanf128
+#define __DECL_SIMD_tanf32x
+#define __DECL_SIMD_tanf64x
+#define __DECL_SIMD_tanf128x
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@libm-simd-decl-stubs.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@libm-simd-decl-stubs.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@local_lim.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@local_lim.h
new file mode 100644
index 0000000000000000000000000000000000000000..39e2cb95401db58a3cfc856e44ff2f05279f6aa0
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@local_lim.h
@@ -0,0 +1,99 @@
+/* Minimum guaranteed maximum values for system limits.  Linux version.
+   Copyright (C) 1993-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public License as
+   published by the Free Software Foundation; either version 2.1 of the
+   License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; see the file COPYING.LIB.  If
+   not, see <https://www.gnu.org/licenses/>.  */
+
+/* The kernel header pollutes the namespace with the NR_OPEN symbol
+   and defines LINK_MAX although filesystems have different maxima.  A
+   similar thing is true for OPEN_MAX: the limit can be changed at
+   runtime and therefore the macro must not be defined.  Remove this
+   after including the header if necessary.  */
+#ifndef NR_OPEN
+# define __undef_NR_OPEN
+#endif
+#ifndef LINK_MAX
+# define __undef_LINK_MAX
+#endif
+#ifndef OPEN_MAX
+# define __undef_OPEN_MAX
+#endif
+#ifndef ARG_MAX
+# define __undef_ARG_MAX
+#endif
+
+/* The kernel sources contain a file with all the needed information.  */
+#include <linux/limits.h>
+
+/* Have to remove NR_OPEN?  */
+#ifdef __undef_NR_OPEN
+# undef NR_OPEN
+# undef __undef_NR_OPEN
+#endif
+/* Have to remove LINK_MAX?  */
+#ifdef __undef_LINK_MAX
+# undef LINK_MAX
+# undef __undef_LINK_MAX
+#endif
+/* Have to remove OPEN_MAX?  */
+#ifdef __undef_OPEN_MAX
+# undef OPEN_MAX
+# undef __undef_OPEN_MAX
+#endif
+/* Have to remove ARG_MAX?  */
+#ifdef __undef_ARG_MAX
+# undef ARG_MAX
+# undef __undef_ARG_MAX
+#endif
+
+/* The number of data keys per process.  */
+#define _POSIX_THREAD_KEYS_MAX	128
+/* This is the value this implementation supports.  */
+#define PTHREAD_KEYS_MAX	1024
+
+/* Controlling the iterations of destructors for thread-specific data.  */
+#define _POSIX_THREAD_DESTRUCTOR_ITERATIONS	4
+/* Number of iterations this implementation does.  */
+#define PTHREAD_DESTRUCTOR_ITERATIONS	_POSIX_THREAD_DESTRUCTOR_ITERATIONS
+
+/* The number of threads per process.  */
+#define _POSIX_THREAD_THREADS_MAX	64
+/* We have no predefined limit on the number of threads.  */
+#undef PTHREAD_THREADS_MAX
+
+/* Maximum amount by which a process can descrease its asynchronous I/O
+   priority level.  */
+#define AIO_PRIO_DELTA_MAX	20
+
+/* Arrange for the definition of PTHREAD_STACK_MIN.  */
+#include <bits/pthread_stack_min-dynamic.h>
+
+/* Maximum number of timer expiration overruns.  */
+#define DELAYTIMER_MAX	2147483647
+
+/* Maximum tty name length.  */
+#define TTY_NAME_MAX		32
+
+/* Maximum login name length.  This is arbitrary.  */
+#define LOGIN_NAME_MAX		256
+
+/* Maximum host name length.  */
+#define HOST_NAME_MAX		64
+
+/* Maximum message queue priority level.  */
+#define MQ_PRIO_MAX		32768
+
+/* Maximum value the semaphore can have.  */
+#define SEM_VALUE_MAX   (2147483647)
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@local_lim.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@local_lim.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@locale.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@locale.h
new file mode 100644
index 0000000000000000000000000000000000000000..ef17a581ca06b12edb943fa49b5320ab100f5331
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@locale.h
@@ -0,0 +1,40 @@
+/* Definition of locale category symbol values.
+   Copyright (C) 2001-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#if !defined _LOCALE_H && !defined _LANGINFO_H
+# error "Never use <bits/locale.h> directly; include <locale.h> instead."
+#endif
+
+#ifndef _BITS_LOCALE_H
+#define _BITS_LOCALE_H	1
+
+#define __LC_CTYPE		 0
+#define __LC_NUMERIC		 1
+#define __LC_TIME		 2
+#define __LC_COLLATE		 3
+#define __LC_MONETARY		 4
+#define __LC_MESSAGES		 5
+#define __LC_ALL		 6
+#define __LC_PAPER		 7
+#define __LC_NAME		 8
+#define __LC_ADDRESS		 9
+#define __LC_TELEPHONE		10
+#define __LC_MEASUREMENT	11
+#define __LC_IDENTIFICATION	12
+
+#endif	/* bits/locale.h */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@locale.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@locale.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@long-double.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@long-double.h
new file mode 100644
index 0000000000000000000000000000000000000000..350df845d2fad2273e6dfeca382978df6d1968df
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@long-double.h
@@ -0,0 +1,21 @@
+/* Properties of long double type.  ldbl-96 version.
+   Copyright (C) 2016-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License  published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+/* long double is distinct from double, so there is nothing to
+   define here.  */
+#define __LDOUBLE_REDIRECTS_TO_FLOAT128_ABI 0
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@long-double.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@long-double.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@math-vector.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@math-vector.h
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index 0000000000000000000000000000000000000000..dc7d84a70766b9f4fcd94be1221cc91747f2907b
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@math-vector.h
@@ -0,0 +1,147 @@
+/* Platform-specific SIMD declarations of math functions.
+   Copyright (C) 2014-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _MATH_H
+# error "Never include <bits/math-vector.h> directly;\
+ include <math.h> instead."
+#endif
+
+/* Get default empty definitions for simd declarations.  */
+#include <bits/libm-simd-decl-stubs.h>
+
+#if defined __x86_64__ && defined __FAST_MATH__
+# if defined _OPENMP && _OPENMP >= 201307
+/* OpenMP case.  */
+#  define __DECL_SIMD_x86_64 _Pragma ("omp declare simd notinbranch")
+# elif __GNUC_PREREQ (6,0)
+/* W/o OpenMP use GCC 6.* __attribute__ ((__simd__)).  */
+#  define __DECL_SIMD_x86_64 __attribute__ ((__simd__ ("notinbranch")))
+# endif
+
+# ifdef __DECL_SIMD_x86_64
+#  undef __DECL_SIMD_cos
+#  define __DECL_SIMD_cos __DECL_SIMD_x86_64
+#  undef __DECL_SIMD_cosf
+#  define __DECL_SIMD_cosf __DECL_SIMD_x86_64
+#  undef __DECL_SIMD_sin
+#  define __DECL_SIMD_sin __DECL_SIMD_x86_64
+#  undef __DECL_SIMD_sinf
+#  define __DECL_SIMD_sinf __DECL_SIMD_x86_64
+#  undef __DECL_SIMD_sincos
+#  define __DECL_SIMD_sincos __DECL_SIMD_x86_64
+#  undef __DECL_SIMD_sincosf
+#  define __DECL_SIMD_sincosf __DECL_SIMD_x86_64
+#  undef __DECL_SIMD_log
+#  define __DECL_SIMD_log __DECL_SIMD_x86_64
+#  undef __DECL_SIMD_logf
+#  define __DECL_SIMD_logf __DECL_SIMD_x86_64
+#  undef __DECL_SIMD_exp
+#  define __DECL_SIMD_exp __DECL_SIMD_x86_64
+#  undef __DECL_SIMD_expf
+#  define __DECL_SIMD_expf __DECL_SIMD_x86_64
+#  undef __DECL_SIMD_pow
+#  define __DECL_SIMD_pow __DECL_SIMD_x86_64
+#  undef __DECL_SIMD_powf
+#  define __DECL_SIMD_powf __DECL_SIMD_x86_64
+#  undef __DECL_SIMD_acos
+#  define __DECL_SIMD_acos __DECL_SIMD_x86_64
+#  undef __DECL_SIMD_acosf
+#  define __DECL_SIMD_acosf __DECL_SIMD_x86_64
+#  undef __DECL_SIMD_atan
+#  define __DECL_SIMD_atan __DECL_SIMD_x86_64
+#  undef __DECL_SIMD_atanf
+#  define __DECL_SIMD_atanf __DECL_SIMD_x86_64
+#  undef __DECL_SIMD_asin
+#  define __DECL_SIMD_asin __DECL_SIMD_x86_64
+#  undef __DECL_SIMD_asinf
+#  define __DECL_SIMD_asinf __DECL_SIMD_x86_64
+#  undef __DECL_SIMD_hypot
+#  define __DECL_SIMD_hypot __DECL_SIMD_x86_64
+#  undef __DECL_SIMD_hypotf
+#  define __DECL_SIMD_hypotf __DECL_SIMD_x86_64
+#  undef __DECL_SIMD_exp2
+#  define __DECL_SIMD_exp2 __DECL_SIMD_x86_64
+#  undef __DECL_SIMD_exp2f
+#  define __DECL_SIMD_exp2f __DECL_SIMD_x86_64
+#  undef __DECL_SIMD_exp10
+#  define __DECL_SIMD_exp10 __DECL_SIMD_x86_64
+#  undef __DECL_SIMD_exp10f
+#  define __DECL_SIMD_exp10f __DECL_SIMD_x86_64
+#  undef __DECL_SIMD_cosh
+#  define __DECL_SIMD_cosh __DECL_SIMD_x86_64
+#  undef __DECL_SIMD_coshf
+#  define __DECL_SIMD_coshf __DECL_SIMD_x86_64
+#  undef __DECL_SIMD_expm1
+#  define __DECL_SIMD_expm1 __DECL_SIMD_x86_64
+#  undef __DECL_SIMD_expm1f
+#  define __DECL_SIMD_expm1f __DECL_SIMD_x86_64
+#  undef __DECL_SIMD_sinh
+#  define __DECL_SIMD_sinh __DECL_SIMD_x86_64
+#  undef __DECL_SIMD_sinhf
+#  define __DECL_SIMD_sinhf __DECL_SIMD_x86_64
+#  undef __DECL_SIMD_cbrt
+#  define __DECL_SIMD_cbrt __DECL_SIMD_x86_64
+#  undef __DECL_SIMD_cbrtf
+#  define __DECL_SIMD_cbrtf __DECL_SIMD_x86_64
+#  undef __DECL_SIMD_atan2
+#  define __DECL_SIMD_atan2 __DECL_SIMD_x86_64
+#  undef __DECL_SIMD_atan2f
+#  define __DECL_SIMD_atan2f __DECL_SIMD_x86_64
+#  undef __DECL_SIMD_log10
+#  define __DECL_SIMD_log10 __DECL_SIMD_x86_64
+#  undef __DECL_SIMD_log10f
+#  define __DECL_SIMD_log10f __DECL_SIMD_x86_64
+#  undef __DECL_SIMD_log2
+#  define __DECL_SIMD_log2 __DECL_SIMD_x86_64
+#  undef __DECL_SIMD_log2f
+#  define __DECL_SIMD_log2f __DECL_SIMD_x86_64
+#  undef __DECL_SIMD_log1p
+#  define __DECL_SIMD_log1p __DECL_SIMD_x86_64
+#  undef __DECL_SIMD_log1pf
+#  define __DECL_SIMD_log1pf __DECL_SIMD_x86_64
+#  undef __DECL_SIMD_atanh
+#  define __DECL_SIMD_atanh __DECL_SIMD_x86_64
+#  undef __DECL_SIMD_atanhf
+#  define __DECL_SIMD_atanhf __DECL_SIMD_x86_64
+#  undef __DECL_SIMD_acosh
+#  define __DECL_SIMD_acosh __DECL_SIMD_x86_64
+#  undef __DECL_SIMD_acoshf
+#  define __DECL_SIMD_acoshf __DECL_SIMD_x86_64
+#  undef __DECL_SIMD_erf
+#  define __DECL_SIMD_erf __DECL_SIMD_x86_64
+#  undef __DECL_SIMD_erff
+#  define __DECL_SIMD_erff __DECL_SIMD_x86_64
+#  undef __DECL_SIMD_tanh
+#  define __DECL_SIMD_tanh __DECL_SIMD_x86_64
+#  undef __DECL_SIMD_tanhf
+#  define __DECL_SIMD_tanhf __DECL_SIMD_x86_64
+#  undef __DECL_SIMD_asinh
+#  define __DECL_SIMD_asinh __DECL_SIMD_x86_64
+#  undef __DECL_SIMD_asinhf
+#  define __DECL_SIMD_asinhf __DECL_SIMD_x86_64
+#  undef __DECL_SIMD_erfc
+#  define __DECL_SIMD_erfc __DECL_SIMD_x86_64
+#  undef __DECL_SIMD_erfcf
+#  define __DECL_SIMD_erfcf __DECL_SIMD_x86_64
+#  undef __DECL_SIMD_tan
+#  define __DECL_SIMD_tan __DECL_SIMD_x86_64
+#  undef __DECL_SIMD_tanf
+#  define __DECL_SIMD_tanf __DECL_SIMD_x86_64
+
+# endif
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@math-vector.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@math-vector.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@mathcalls-helper-functions.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@mathcalls-helper-functions.h
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index 0000000000000000000000000000000000000000..932fd117ba49cc2422fa375fa29eab72f348724a
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@mathcalls-helper-functions.h
@@ -0,0 +1,45 @@
+/* Prototype declarations for math classification macros helpers.
+   Copyright (C) 2017-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+/* Classify given number.  */
+__MATHDECL_ALIAS (int, __fpclassify,, (_Mdouble_ __value), fpclassify)
+     __attribute__ ((__const__));
+
+/* Test for negative number.  */
+__MATHDECL_ALIAS (int, __signbit,, (_Mdouble_ __value), signbit)
+     __attribute__ ((__const__));
+
+/* Return 0 if VALUE is finite or NaN, +1 if it
+   is +Infinity, -1 if it is -Infinity.  */
+__MATHDECL_ALIAS (int, __isinf,, (_Mdouble_ __value), isinf)
+  __attribute__ ((__const__));
+
+/* Return nonzero if VALUE is finite and not NaN.  Used by isfinite macro.  */
+__MATHDECL_ALIAS (int, __finite,, (_Mdouble_ __value), finite)
+  __attribute__ ((__const__));
+
+/* Return nonzero if VALUE is not a number.  */
+__MATHDECL_ALIAS (int, __isnan,, (_Mdouble_ __value), isnan)
+  __attribute__ ((__const__));
+
+/* Test equality.  */
+__MATHDECL_ALIAS (int, __iseqsig,, (_Mdouble_ __x, _Mdouble_ __y), iseqsig);
+
+/* Test for signaling NaN.  */
+__MATHDECL_ALIAS (int, __issignaling,, (_Mdouble_ __value), issignaling)
+     __attribute__ ((__const__));
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@mathcalls-helper-functions.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@mathcalls-helper-functions.h.blob
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--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@mathcalls-narrow.h
@@ -0,0 +1,39 @@
+/* Declare functions returning a narrower type.
+   Copyright (C) 2018-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _MATH_H
+# error "Never include <bits/mathcalls-narrow.h> directly; include <math.h> instead."
+#endif
+
+/* Add.  */
+__MATHCALL_NARROW (__MATHCALL_NAME (add), __MATHCALL_REDIR_NAME (add), 2);
+
+/* Divide.  */
+__MATHCALL_NARROW (__MATHCALL_NAME (div), __MATHCALL_REDIR_NAME (div), 2);
+
+/* Fused multiply-add.  */
+__MATHCALL_NARROW (__MATHCALL_NAME (fma), __MATHCALL_REDIR_NAME2 (fma), 3);
+
+/* Multiply.  */
+__MATHCALL_NARROW (__MATHCALL_NAME (mul), __MATHCALL_REDIR_NAME (mul), 2);
+
+/* Square root.  */
+__MATHCALL_NARROW (__MATHCALL_NAME (sqrt), __MATHCALL_REDIR_NAME2 (sqrt), 1);
+
+/* Subtract.  */
+__MATHCALL_NARROW (__MATHCALL_NAME (sub), __MATHCALL_REDIR_NAME (sub), 2);
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@mathcalls-narrow.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@mathcalls-narrow.h.blob
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@mathcalls.h
@@ -0,0 +1,436 @@
+/* Prototype declarations for math functions; helper file for <math.h>.
+   Copyright (C) 1996-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+/* NOTE: Because of the special way this file is used by <math.h>, this
+   file must NOT be protected from multiple inclusion as header files
+   usually are.
+
+   This file provides prototype declarations for the math functions.
+   Most functions are declared using the macro:
+
+   __MATHCALL (NAME,[_r], (ARGS...));
+
+   This means there is a function `NAME' returning `double' and a function
+   `NAMEf' returning `float'.  Each place `_Mdouble_' appears in the
+   prototype, that is actually `double' in the prototype for `NAME' and
+   `float' in the prototype for `NAMEf'.  Reentrant variant functions are
+   called `NAME_r' and `NAMEf_r'.
+
+   Functions returning other types like `int' are declared using the macro:
+
+   __MATHDECL (TYPE, NAME,[_r], (ARGS...));
+
+   This is just like __MATHCALL but for a function returning `TYPE'
+   instead of `_Mdouble_'.  In all of these cases, there is still
+   both a `NAME' and a `NAMEf' that takes `float' arguments.
+
+   Note that there must be no whitespace before the argument passed for
+   NAME, to make token pasting work with -traditional.  */
+
+#ifndef _MATH_H
+# error "Never include <bits/mathcalls.h> directly; include <math.h> instead."
+#endif
+
+
+/* Trigonometric functions.  */
+
+/* Arc cosine of X.  */
+__MATHCALL_VEC (acos,, (_Mdouble_ __x));
+/* Arc sine of X.  */
+__MATHCALL_VEC (asin,, (_Mdouble_ __x));
+/* Arc tangent of X.  */
+__MATHCALL_VEC (atan,, (_Mdouble_ __x));
+/* Arc tangent of Y/X.  */
+__MATHCALL_VEC (atan2,, (_Mdouble_ __y, _Mdouble_ __x));
+
+/* Cosine of X.  */
+__MATHCALL_VEC (cos,, (_Mdouble_ __x));
+/* Sine of X.  */
+__MATHCALL_VEC (sin,, (_Mdouble_ __x));
+/* Tangent of X.  */
+__MATHCALL_VEC (tan,, (_Mdouble_ __x));
+
+/* Hyperbolic functions.  */
+
+/* Hyperbolic cosine of X.  */
+__MATHCALL_VEC (cosh,, (_Mdouble_ __x));
+/* Hyperbolic sine of X.  */
+__MATHCALL_VEC (sinh,, (_Mdouble_ __x));
+/* Hyperbolic tangent of X.  */
+__MATHCALL_VEC (tanh,, (_Mdouble_ __x));
+
+#ifdef __USE_GNU
+/* Cosine and sine of X.  */
+__MATHDECL_VEC (void,sincos,,
+		(_Mdouble_ __x, _Mdouble_ *__sinx, _Mdouble_ *__cosx));
+#endif
+
+#if defined __USE_XOPEN_EXTENDED || defined __USE_ISOC99
+/* Hyperbolic arc cosine of X.  */
+__MATHCALL_VEC (acosh,, (_Mdouble_ __x));
+/* Hyperbolic arc sine of X.  */
+__MATHCALL_VEC (asinh,, (_Mdouble_ __x));
+/* Hyperbolic arc tangent of X.  */
+__MATHCALL_VEC (atanh,, (_Mdouble_ __x));
+#endif
+
+/* Exponential and logarithmic functions.  */
+
+/* Exponential function of X.  */
+__MATHCALL_VEC (exp,, (_Mdouble_ __x));
+
+/* Break VALUE into a normalized fraction and an integral power of 2.  */
+__MATHCALL (frexp,, (_Mdouble_ __x, int *__exponent));
+
+/* X times (two to the EXP power).  */
+__MATHCALL (ldexp,, (_Mdouble_ __x, int __exponent));
+
+/* Natural logarithm of X.  */
+__MATHCALL_VEC (log,, (_Mdouble_ __x));
+
+/* Base-ten logarithm of X.  */
+__MATHCALL_VEC (log10,, (_Mdouble_ __x));
+
+/* Break VALUE into integral and fractional parts.  */
+__MATHCALL (modf,, (_Mdouble_ __x, _Mdouble_ *__iptr)) __nonnull ((2));
+
+#if __GLIBC_USE (IEC_60559_FUNCS_EXT_C2X)
+/* Compute exponent to base ten.  */
+__MATHCALL_VEC (exp10,, (_Mdouble_ __x));
+#endif
+
+#if defined __USE_XOPEN_EXTENDED || defined __USE_ISOC99
+/* Return exp(X) - 1.  */
+__MATHCALL_VEC (expm1,, (_Mdouble_ __x));
+
+/* Return log(1 + X).  */
+__MATHCALL_VEC (log1p,, (_Mdouble_ __x));
+
+/* Return the base 2 signed integral exponent of X.  */
+__MATHCALL (logb,, (_Mdouble_ __x));
+#endif
+
+#ifdef __USE_ISOC99
+/* Compute base-2 exponential of X.  */
+__MATHCALL_VEC (exp2,, (_Mdouble_ __x));
+
+/* Compute base-2 logarithm of X.  */
+__MATHCALL_VEC (log2,, (_Mdouble_ __x));
+#endif
+
+
+/* Power functions.  */
+
+/* Return X to the Y power.  */
+__MATHCALL_VEC (pow,, (_Mdouble_ __x, _Mdouble_ __y));
+
+/* Return the square root of X.  */
+__MATHCALL (sqrt,, (_Mdouble_ __x));
+
+#if defined __USE_XOPEN || defined __USE_ISOC99
+/* Return `sqrt(X*X + Y*Y)'.  */
+__MATHCALL_VEC (hypot,, (_Mdouble_ __x, _Mdouble_ __y));
+#endif
+
+#if defined __USE_XOPEN_EXTENDED || defined __USE_ISOC99
+/* Return the cube root of X.  */
+__MATHCALL_VEC (cbrt,, (_Mdouble_ __x));
+#endif
+
+
+/* Nearest integer, absolute value, and remainder functions.  */
+
+/* Smallest integral value not less than X.  */
+__MATHCALLX (ceil,, (_Mdouble_ __x), (__const__));
+
+/* Absolute value of X.  */
+__MATHCALLX (fabs,, (_Mdouble_ __x), (__const__));
+
+/* Largest integer not greater than X.  */
+__MATHCALLX (floor,, (_Mdouble_ __x), (__const__));
+
+/* Floating-point modulo remainder of X/Y.  */
+__MATHCALL (fmod,, (_Mdouble_ __x, _Mdouble_ __y));
+
+#ifdef __USE_MISC
+# if ((!defined __cplusplus \
+       || __cplusplus < 201103L /* isinf conflicts with C++11.  */ \
+       || __MATH_DECLARING_DOUBLE == 0)) /* isinff or isinfl don't.  */ \
+      && !__MATH_DECLARING_FLOATN
+/* Return 0 if VALUE is finite or NaN, +1 if it
+   is +Infinity, -1 if it is -Infinity.  */
+__MATHDECL_ALIAS (int,isinf,, (_Mdouble_ __value), isinf)
+  __attribute__ ((__const__));
+# endif
+
+# if !__MATH_DECLARING_FLOATN
+/* Return nonzero if VALUE is finite and not NaN.  */
+__MATHDECL_ALIAS (int,finite,, (_Mdouble_ __value), finite)
+  __attribute__ ((__const__));
+
+/* Return the remainder of X/Y.  */
+__MATHCALL (drem,, (_Mdouble_ __x, _Mdouble_ __y));
+
+
+/* Return the fractional part of X after dividing out `ilogb (X)'.  */
+__MATHCALL (significand,, (_Mdouble_ __x));
+# endif
+
+#endif /* Use misc.  */
+
+#ifdef __USE_ISOC99
+/* Return X with its signed changed to Y's.  */
+__MATHCALLX (copysign,, (_Mdouble_ __x, _Mdouble_ __y), (__const__));
+#endif
+
+#ifdef __USE_ISOC99
+/* Return representation of qNaN for double type.  */
+__MATHCALL (nan,, (const char *__tagb));
+#endif
+
+
+#if defined __USE_MISC || (defined __USE_XOPEN && !defined __USE_XOPEN2K)
+# if ((!defined __cplusplus \
+       || __cplusplus < 201103L /* isnan conflicts with C++11.  */ \
+       || __MATH_DECLARING_DOUBLE == 0)) /* isnanf or isnanl don't.  */ \
+      && !__MATH_DECLARING_FLOATN
+/* Return nonzero if VALUE is not a number.  */
+__MATHDECL_ALIAS (int,isnan,, (_Mdouble_ __value), isnan)
+  __attribute__ ((__const__));
+# endif
+#endif
+
+#if defined __USE_MISC || (defined __USE_XOPEN && __MATH_DECLARING_DOUBLE)
+/* Bessel functions.  */
+__MATHCALL (j0,, (_Mdouble_));
+__MATHCALL (j1,, (_Mdouble_));
+__MATHCALL (jn,, (int, _Mdouble_));
+__MATHCALL (y0,, (_Mdouble_));
+__MATHCALL (y1,, (_Mdouble_));
+__MATHCALL (yn,, (int, _Mdouble_));
+#endif
+
+
+#if defined __USE_XOPEN || defined __USE_ISOC99
+/* Error and gamma functions.  */
+__MATHCALL_VEC (erf,, (_Mdouble_));
+__MATHCALL_VEC (erfc,, (_Mdouble_));
+__MATHCALL (lgamma,, (_Mdouble_));
+#endif
+
+#ifdef __USE_ISOC99
+/* True gamma function.  */
+__MATHCALL (tgamma,, (_Mdouble_));
+#endif
+
+#if defined __USE_MISC || (defined __USE_XOPEN && !defined __USE_XOPEN2K)
+# if !__MATH_DECLARING_FLOATN
+/* Obsolete alias for `lgamma'.  */
+__MATHCALL (gamma,, (_Mdouble_));
+# endif
+#endif
+
+#ifdef __USE_MISC
+/* Reentrant version of lgamma.  This function uses the global variable
+   `signgam'.  The reentrant version instead takes a pointer and stores
+   the value through it.  */
+__MATHCALL (lgamma,_r, (_Mdouble_, int *__signgamp));
+#endif
+
+
+#if defined __USE_XOPEN_EXTENDED || defined __USE_ISOC99
+/* Return the integer nearest X in the direction of the
+   prevailing rounding mode.  */
+__MATHCALL (rint,, (_Mdouble_ __x));
+
+/* Return X + epsilon if X < Y, X - epsilon if X > Y.  */
+__MATHCALL (nextafter,, (_Mdouble_ __x, _Mdouble_ __y));
+# if defined __USE_ISOC99 && !defined __LDBL_COMPAT && !__MATH_DECLARING_FLOATN
+__MATHCALL (nexttoward,, (_Mdouble_ __x, long double __y));
+# endif
+
+# if __GLIBC_USE (IEC_60559_BFP_EXT_C2X) || __MATH_DECLARING_FLOATN
+/* Return X - epsilon.  */
+__MATHCALL (nextdown,, (_Mdouble_ __x));
+/* Return X + epsilon.  */
+__MATHCALL (nextup,, (_Mdouble_ __x));
+# endif
+
+/* Return the remainder of integer divison X / Y with infinite precision.  */
+__MATHCALL (remainder,, (_Mdouble_ __x, _Mdouble_ __y));
+
+# ifdef __USE_ISOC99
+/* Return X times (2 to the Nth power).  */
+__MATHCALL (scalbn,, (_Mdouble_ __x, int __n));
+# endif
+
+/* Return the binary exponent of X, which must be nonzero.  */
+__MATHDECL (int,ilogb,, (_Mdouble_ __x));
+#endif
+
+#if __GLIBC_USE (IEC_60559_BFP_EXT_C2X) || __MATH_DECLARING_FLOATN
+/* Like ilogb, but returning long int.  */
+__MATHDECL (long int, llogb,, (_Mdouble_ __x));
+#endif
+
+#ifdef __USE_ISOC99
+/* Return X times (2 to the Nth power).  */
+__MATHCALL (scalbln,, (_Mdouble_ __x, long int __n));
+
+/* Round X to integral value in floating-point format using current
+   rounding direction, but do not raise inexact exception.  */
+__MATHCALL (nearbyint,, (_Mdouble_ __x));
+
+/* Round X to nearest integral value, rounding halfway cases away from
+   zero.  */
+__MATHCALLX (round,, (_Mdouble_ __x), (__const__));
+
+/* Round X to the integral value in floating-point format nearest but
+   not larger in magnitude.  */
+__MATHCALLX (trunc,, (_Mdouble_ __x), (__const__));
+
+/* Compute remainder of X and Y and put in *QUO a value with sign of x/y
+   and magnitude congruent `mod 2^n' to the magnitude of the integral
+   quotient x/y, with n >= 3.  */
+__MATHCALL (remquo,, (_Mdouble_ __x, _Mdouble_ __y, int *__quo));
+
+
+/* Conversion functions.  */
+
+/* Round X to nearest integral value according to current rounding
+   direction.  */
+__MATHDECL (long int,lrint,, (_Mdouble_ __x));
+__extension__
+__MATHDECL (long long int,llrint,, (_Mdouble_ __x));
+
+/* Round X to nearest integral value, rounding halfway cases away from
+   zero.  */
+__MATHDECL (long int,lround,, (_Mdouble_ __x));
+__extension__
+__MATHDECL (long long int,llround,, (_Mdouble_ __x));
+
+
+/* Return positive difference between X and Y.  */
+__MATHCALL (fdim,, (_Mdouble_ __x, _Mdouble_ __y));
+
+# if !__MATH_DECLARING_FLOATN || defined __USE_GNU || !__GLIBC_USE (ISOC2X)
+/* Return maximum numeric value from X and Y.  */
+__MATHCALLX (fmax,, (_Mdouble_ __x, _Mdouble_ __y), (__const__));
+
+/* Return minimum numeric value from X and Y.  */
+__MATHCALLX (fmin,, (_Mdouble_ __x, _Mdouble_ __y), (__const__));
+# endif
+
+/* Multiply-add function computed as a ternary operation.  */
+__MATHCALL (fma,, (_Mdouble_ __x, _Mdouble_ __y, _Mdouble_ __z));
+#endif /* Use ISO C99.  */
+
+#if __GLIBC_USE (IEC_60559_BFP_EXT_C2X) || __MATH_DECLARING_FLOATN
+/* Round X to nearest integer value, rounding halfway cases to even.  */
+__MATHCALLX (roundeven,, (_Mdouble_ __x), (__const__));
+
+/* Round X to nearest signed integer value, not raising inexact, with
+   control of rounding direction and width of result.  */
+__MATHDECL (__intmax_t, fromfp,, (_Mdouble_ __x, int __round,
+				  unsigned int __width));
+
+/* Round X to nearest unsigned integer value, not raising inexact,
+   with control of rounding direction and width of result.  */
+__MATHDECL (__uintmax_t, ufromfp,, (_Mdouble_ __x, int __round,
+				    unsigned int __width));
+
+/* Round X to nearest signed integer value, raising inexact for
+   non-integers, with control of rounding direction and width of
+   result.  */
+__MATHDECL (__intmax_t, fromfpx,, (_Mdouble_ __x, int __round,
+				   unsigned int __width));
+
+/* Round X to nearest unsigned integer value, raising inexact for
+   non-integers, with control of rounding direction and width of
+   result.  */
+__MATHDECL (__uintmax_t, ufromfpx,, (_Mdouble_ __x, int __round,
+				     unsigned int __width));
+
+/* Canonicalize floating-point representation.  */
+__MATHDECL_1 (int, canonicalize,, (_Mdouble_ *__cx, const _Mdouble_ *__x));
+#endif
+
+#if (__GLIBC_USE (IEC_60559_BFP_EXT)				\
+     || (__MATH_DECLARING_FLOATN				\
+	 && (defined __USE_GNU || !__GLIBC_USE (ISOC2X))))
+/* Return value with maximum magnitude.  */
+__MATHCALLX (fmaxmag,, (_Mdouble_ __x, _Mdouble_ __y), (__const__));
+
+/* Return value with minimum magnitude.  */
+__MATHCALLX (fminmag,, (_Mdouble_ __x, _Mdouble_ __y), (__const__));
+#endif
+
+#if __GLIBC_USE (ISOC2X)
+/* Return maximum value from X and Y.  */
+__MATHCALLX (fmaximum,, (_Mdouble_ __x, _Mdouble_ __y), (__const__));
+
+/* Return minimum value from X and Y.  */
+__MATHCALLX (fminimum,, (_Mdouble_ __x, _Mdouble_ __y), (__const__));
+
+/* Return maximum numeric value from X and Y.  */
+__MATHCALLX (fmaximum_num,, (_Mdouble_ __x, _Mdouble_ __y), (__const__));
+
+/* Return minimum numeric value from X and Y.  */
+__MATHCALLX (fminimum_num,, (_Mdouble_ __x, _Mdouble_ __y), (__const__));
+
+/* Return value with maximum magnitude.  */
+__MATHCALLX (fmaximum_mag,, (_Mdouble_ __x, _Mdouble_ __y), (__const__));
+
+/* Return value with minimum magnitude.  */
+__MATHCALLX (fminimum_mag,, (_Mdouble_ __x, _Mdouble_ __y), (__const__));
+
+/* Return numeric value with maximum magnitude.  */
+__MATHCALLX (fmaximum_mag_num,, (_Mdouble_ __x, _Mdouble_ __y), (__const__));
+
+/* Return numeric value with minimum magnitude.  */
+__MATHCALLX (fminimum_mag_num,, (_Mdouble_ __x, _Mdouble_ __y), (__const__));
+#endif
+
+#if __GLIBC_USE (IEC_60559_EXT) || __MATH_DECLARING_FLOATN
+/* Total order operation.  */
+__MATHDECL_1 (int, totalorder,, (const _Mdouble_ *__x,
+				 const _Mdouble_ *__y))
+     __attribute_pure__;
+
+/* Total order operation on absolute values.  */
+__MATHDECL_1 (int, totalordermag,, (const _Mdouble_ *__x,
+				    const _Mdouble_ *__y))
+     __attribute_pure__;
+
+/* Get NaN payload.  */
+__MATHCALL (getpayload,, (const _Mdouble_ *__x));
+
+/* Set quiet NaN payload.  */
+__MATHDECL_1 (int, setpayload,, (_Mdouble_ *__x, _Mdouble_ __payload));
+
+/* Set signaling NaN payload.  */
+__MATHDECL_1 (int, setpayloadsig,, (_Mdouble_ *__x, _Mdouble_ __payload));
+#endif
+
+#if (defined __USE_MISC || (defined __USE_XOPEN_EXTENDED \
+			    && __MATH_DECLARING_DOUBLE	  \
+			    && !defined __USE_XOPEN2K8))  \
+     && !__MATH_DECLARING_FLOATN
+/* Return X times (2 to the Nth power).  */
+__MATHCALL (scalb,, (_Mdouble_ __x, _Mdouble_ __n));
+#endif
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@@ -0,0 +1,183 @@
+/* Copyright (C) 1991-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+/*
+ *	POSIX Standard: 2.9.2 Minimum Values	Added to <limits.h>
+ *
+ *	Never include this file directly; use <limits.h> instead.
+ */
+
+#ifndef	_BITS_POSIX1_LIM_H
+#define	_BITS_POSIX1_LIM_H	1
+
+#include <bits/wordsize.h>
+
+/* These are the standard-mandated minimum values.  */
+
+/* Minimum number of operations in one list I/O call.  */
+#define _POSIX_AIO_LISTIO_MAX	2
+
+/* Minimal number of outstanding asynchronous I/O operations.  */
+#define _POSIX_AIO_MAX		1
+
+/* Maximum length of arguments to `execve', including environment.  */
+#define	_POSIX_ARG_MAX		4096
+
+/* Maximum simultaneous processes per real user ID.  */
+#ifdef __USE_XOPEN2K
+# define _POSIX_CHILD_MAX	25
+#else
+# define _POSIX_CHILD_MAX	6
+#endif
+
+/* Minimal number of timer expiration overruns.  */
+#define _POSIX_DELAYTIMER_MAX	32
+
+/* Maximum length of a host name (not including the terminating null)
+   as returned from the GETHOSTNAME function.  */
+#define _POSIX_HOST_NAME_MAX	255
+
+/* Maximum link count of a file.  */
+#define	_POSIX_LINK_MAX		8
+
+/* Maximum length of login name.  */
+#define	_POSIX_LOGIN_NAME_MAX	9
+
+/* Number of bytes in a terminal canonical input queue.  */
+#define	_POSIX_MAX_CANON	255
+
+/* Number of bytes for which space will be
+   available in a terminal input queue.  */
+#define	_POSIX_MAX_INPUT	255
+
+/* Maximum number of message queues open for a process.  */
+#define _POSIX_MQ_OPEN_MAX	8
+
+/* Maximum number of supported message priorities.  */
+#define _POSIX_MQ_PRIO_MAX	32
+
+/* Number of bytes in a filename.  */
+#define	_POSIX_NAME_MAX		14
+
+/* Number of simultaneous supplementary group IDs per process.  */
+#ifdef __USE_XOPEN2K
+# define _POSIX_NGROUPS_MAX	8
+#else
+# define _POSIX_NGROUPS_MAX	0
+#endif
+
+/* Number of files one process can have open at once.  */
+#ifdef __USE_XOPEN2K
+# define _POSIX_OPEN_MAX	20
+#else
+# define _POSIX_OPEN_MAX	16
+#endif
+
+#if !defined __USE_XOPEN2K || defined __USE_GNU
+/* Number of descriptors that a process may examine with `pselect' or
+   `select'.  */
+# define _POSIX_FD_SETSIZE	_POSIX_OPEN_MAX
+#endif
+
+/* Number of bytes in a pathname.  */
+#define	_POSIX_PATH_MAX		256
+
+/* Number of bytes than can be written atomically to a pipe.  */
+#define	_POSIX_PIPE_BUF		512
+
+/* The number of repeated occurrences of a BRE permitted by the
+   REGEXEC and REGCOMP functions when using the interval notation.  */
+#define _POSIX_RE_DUP_MAX	255
+
+/* Minimal number of realtime signals reserved for the application.  */
+#define _POSIX_RTSIG_MAX	8
+
+/* Number of semaphores a process can have.  */
+#define _POSIX_SEM_NSEMS_MAX	256
+
+/* Maximal value of a semaphore.  */
+#define _POSIX_SEM_VALUE_MAX	32767
+
+/* Number of pending realtime signals.  */
+#define _POSIX_SIGQUEUE_MAX	32
+
+/* Largest value of a `ssize_t'.  */
+#define	_POSIX_SSIZE_MAX	32767
+
+/* Number of streams a process can have open at once.  */
+#define	_POSIX_STREAM_MAX	8
+
+/* The number of bytes in a symbolic link.  */
+#define _POSIX_SYMLINK_MAX	255
+
+/* The number of symbolic links that can be traversed in the
+   resolution of a pathname in the absence of a loop.  */
+#define _POSIX_SYMLOOP_MAX	8
+
+/* Number of timer for a process.  */
+#define _POSIX_TIMER_MAX	32
+
+/* Maximum number of characters in a tty name.  */
+#define	_POSIX_TTY_NAME_MAX	9
+
+/* Maximum length of a timezone name (element of `tzname').  */
+#ifdef __USE_XOPEN2K
+# define _POSIX_TZNAME_MAX	6
+#else
+# define _POSIX_TZNAME_MAX	3
+#endif
+
+#if !defined __USE_XOPEN2K || defined __USE_GNU
+/* Maximum number of connections that can be queued on a socket.  */
+# define _POSIX_QLIMIT		1
+
+/* Maximum number of bytes that can be buffered on a socket for send
+   or receive.  */
+# define _POSIX_HIWAT		_POSIX_PIPE_BUF
+
+/* Maximum number of elements in an `iovec' array.  */
+# define _POSIX_UIO_MAXIOV	16
+#endif
+
+/* Maximum clock resolution in nanoseconds.  */
+#define _POSIX_CLOCKRES_MIN	20000000
+
+
+/* Get the implementation-specific values for the above.  */
+#include <bits/local_lim.h>
+
+
+#ifndef	SSIZE_MAX
+/* ssize_t is not formally required to be the signed type
+   corresponding to size_t, but it is for all configurations supported
+   by glibc.  */
+# if __WORDSIZE == 64 || __WORDSIZE32_SIZE_ULONG
+#  define SSIZE_MAX	LONG_MAX
+# else
+#  define SSIZE_MAX	INT_MAX
+# endif
+#endif
+
+
+/* This value is a guaranteed minimum maximum.
+   The current maximum can be got from `sysconf'.  */
+
+#ifndef	NGROUPS_MAX
+# define NGROUPS_MAX	8
+#endif
+
+#endif	/* bits/posix1_lim.h  */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@posix1_lim.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@posix1_lim.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@posix2_lim.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@posix2_lim.h
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--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@posix2_lim.h
@@ -0,0 +1,90 @@
+/* Copyright (C) 1991-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+/*
+ * Never include this file directly; include <limits.h> instead.
+ */
+
+#ifndef	_BITS_POSIX2_LIM_H
+#define	_BITS_POSIX2_LIM_H	1
+
+
+/* The maximum `ibase' and `obase' values allowed by the `bc' utility.  */
+#define	_POSIX2_BC_BASE_MAX		99
+
+/* The maximum number of elements allowed in an array by the `bc' utility.  */
+#define	_POSIX2_BC_DIM_MAX		2048
+
+/* The maximum `scale' value allowed by the `bc' utility.  */
+#define	_POSIX2_BC_SCALE_MAX		99
+
+/* The maximum length of a string constant accepted by the `bc' utility.  */
+#define	_POSIX2_BC_STRING_MAX		1000
+
+/* The maximum number of weights that can be assigned to an entry of
+   the LC_COLLATE `order' keyword in the locale definition file.  */
+#define	_POSIX2_COLL_WEIGHTS_MAX	2
+
+/* The maximum number of expressions that can be nested
+   within parentheses by the `expr' utility.  */
+#define	_POSIX2_EXPR_NEST_MAX		32
+
+/* The maximum length, in bytes, of an input line.  */
+#define	_POSIX2_LINE_MAX		2048
+
+/* The maximum number of repeated occurrences of a regular expression
+   permitted when using the interval notation `\{M,N\}'.  */
+#define	_POSIX2_RE_DUP_MAX		255
+
+/* The maximum number of bytes in a character class name.  We have no
+   fixed limit, 2048 is a high number.  */
+#define	_POSIX2_CHARCLASS_NAME_MAX	14
+
+
+/* These values are implementation-specific,
+   and may vary within the implementation.
+   Their precise values can be obtained from sysconf.  */
+
+#ifndef	BC_BASE_MAX
+#define	BC_BASE_MAX		_POSIX2_BC_BASE_MAX
+#endif
+#ifndef	BC_DIM_MAX
+#define	BC_DIM_MAX		_POSIX2_BC_DIM_MAX
+#endif
+#ifndef	BC_SCALE_MAX
+#define	BC_SCALE_MAX		_POSIX2_BC_SCALE_MAX
+#endif
+#ifndef	BC_STRING_MAX
+#define	BC_STRING_MAX		_POSIX2_BC_STRING_MAX
+#endif
+#ifndef	COLL_WEIGHTS_MAX
+#define	COLL_WEIGHTS_MAX	255
+#endif
+#ifndef	EXPR_NEST_MAX
+#define	EXPR_NEST_MAX		_POSIX2_EXPR_NEST_MAX
+#endif
+#ifndef	LINE_MAX
+#define	LINE_MAX		_POSIX2_LINE_MAX
+#endif
+#ifndef	CHARCLASS_NAME_MAX
+#define	CHARCLASS_NAME_MAX	2048
+#endif
+
+/* This value is defined like this in regex.h.  */
+#define	RE_DUP_MAX (0x7fff)
+
+#endif	/* bits/posix2_lim.h */
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@posix_opt.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@posix_opt.h
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@posix_opt.h
@@ -0,0 +1,194 @@
+/* Define POSIX options for Linux.
+   Copyright (C) 1996-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public License as
+   published by the Free Software Foundation; either version 2.1 of the
+   License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; see the file COPYING.LIB.  If
+   not, see <https://www.gnu.org/licenses/>.  */
+
+#ifndef	_BITS_POSIX_OPT_H
+#define	_BITS_POSIX_OPT_H	1
+
+/* Job control is supported.  */
+#define	_POSIX_JOB_CONTROL	1
+
+/* Processes have a saved set-user-ID and a saved set-group-ID.  */
+#define	_POSIX_SAVED_IDS	1
+
+/* Priority scheduling is not supported with the correct semantics,
+   but GNU/Linux applications expect that the corresponding interfaces
+   are available, even though the semantics do not meet the POSIX
+   requirements.  See glibc bug 14829.  */
+#define	_POSIX_PRIORITY_SCHEDULING	200809L
+
+/* Synchronizing file data is supported.  */
+#define	_POSIX_SYNCHRONIZED_IO	200809L
+
+/* The fsync function is present.  */
+#define	_POSIX_FSYNC	200809L
+
+/* Mapping of files to memory is supported.  */
+#define	_POSIX_MAPPED_FILES	200809L
+
+/* Locking of all memory is supported.  */
+#define	_POSIX_MEMLOCK	200809L
+
+/* Locking of ranges of memory is supported.  */
+#define	_POSIX_MEMLOCK_RANGE	200809L
+
+/* Setting of memory protections is supported.  */
+#define	_POSIX_MEMORY_PROTECTION	200809L
+
+/* Some filesystems allow all users to change file ownership.  */
+#define	_POSIX_CHOWN_RESTRICTED	0
+
+/* `c_cc' member of 'struct termios' structure can be disabled by
+   using the value _POSIX_VDISABLE.  */
+#define	_POSIX_VDISABLE	'\0'
+
+/* Filenames are not silently truncated.  */
+#define	_POSIX_NO_TRUNC	1
+
+/* X/Open realtime support is available.  */
+#define _XOPEN_REALTIME	1
+
+/* X/Open thread realtime support is available.  */
+#define _XOPEN_REALTIME_THREADS	1
+
+/* XPG4.2 shared memory is supported.  */
+#define	_XOPEN_SHM	1
+
+/* Tell we have POSIX threads.  */
+#define _POSIX_THREADS	200809L
+
+/* We have the reentrant functions described in POSIX.  */
+#define _POSIX_REENTRANT_FUNCTIONS      1
+#define _POSIX_THREAD_SAFE_FUNCTIONS	200809L
+
+/* We provide priority scheduling for threads.  */
+#define _POSIX_THREAD_PRIORITY_SCHEDULING	200809L
+
+/* We support user-defined stack sizes.  */
+#define _POSIX_THREAD_ATTR_STACKSIZE	200809L
+
+/* We support user-defined stacks.  */
+#define _POSIX_THREAD_ATTR_STACKADDR	200809L
+
+/* We support priority inheritence.  */
+#define _POSIX_THREAD_PRIO_INHERIT	200809L
+
+/* We support priority protection, though only for non-robust
+   mutexes.  */
+#define _POSIX_THREAD_PRIO_PROTECT	200809L
+
+#ifdef __USE_XOPEN2K8
+/* We support priority inheritence for robust mutexes.  */
+# define _POSIX_THREAD_ROBUST_PRIO_INHERIT	200809L
+
+/* We do not support priority protection for robust mutexes.  */
+# define _POSIX_THREAD_ROBUST_PRIO_PROTECT	-1
+#endif
+
+/* We support POSIX.1b semaphores.  */
+#define _POSIX_SEMAPHORES	200809L
+
+/* Real-time signals are supported.  */
+#define _POSIX_REALTIME_SIGNALS	200809L
+
+/* We support asynchronous I/O.  */
+#define _POSIX_ASYNCHRONOUS_IO	200809L
+#define _POSIX_ASYNC_IO		1
+/* Alternative name for Unix98.  */
+#define _LFS_ASYNCHRONOUS_IO	1
+/* Support for prioritization is also available.  */
+#define _POSIX_PRIORITIZED_IO	200809L
+
+/* The LFS support in asynchronous I/O is also available.  */
+#define _LFS64_ASYNCHRONOUS_IO	1
+
+/* The rest of the LFS is also available.  */
+#define _LFS_LARGEFILE		1
+#define _LFS64_LARGEFILE	1
+#define _LFS64_STDIO		1
+
+/* POSIX shared memory objects are implemented.  */
+#define _POSIX_SHARED_MEMORY_OBJECTS	200809L
+
+/* CPU-time clocks support needs to be checked at runtime.  */
+#define _POSIX_CPUTIME	0
+
+/* Clock support in threads must be also checked at runtime.  */
+#define _POSIX_THREAD_CPUTIME	0
+
+/* GNU libc provides regular expression handling.  */
+#define _POSIX_REGEXP	1
+
+/* Reader/Writer locks are available.  */
+#define _POSIX_READER_WRITER_LOCKS	200809L
+
+/* We have a POSIX shell.  */
+#define _POSIX_SHELL	1
+
+/* We support the Timeouts option.  */
+#define _POSIX_TIMEOUTS	200809L
+
+/* We support spinlocks.  */
+#define _POSIX_SPIN_LOCKS	200809L
+
+/* The `spawn' function family is supported.  */
+#define _POSIX_SPAWN	200809L
+
+/* We have POSIX timers.  */
+#define _POSIX_TIMERS	200809L
+
+/* The barrier functions are available.  */
+#define _POSIX_BARRIERS	200809L
+
+/* POSIX message queues are available.  */
+#define	_POSIX_MESSAGE_PASSING	200809L
+
+/* Thread process-shared synchronization is supported.  */
+#define _POSIX_THREAD_PROCESS_SHARED	200809L
+
+/* The monotonic clock might be available.  */
+#define _POSIX_MONOTONIC_CLOCK	0
+
+/* The clock selection interfaces are available.  */
+#define _POSIX_CLOCK_SELECTION	200809L
+
+/* Advisory information interfaces are available.  */
+#define _POSIX_ADVISORY_INFO	200809L
+
+/* IPv6 support is available.  */
+#define _POSIX_IPV6	200809L
+
+/* Raw socket support is available.  */
+#define _POSIX_RAW_SOCKETS	200809L
+
+/* We have at least one terminal.  */
+#define _POSIX2_CHAR_TERM	200809L
+
+/* Neither process nor thread sporadic server interfaces is available.  */
+#define _POSIX_SPORADIC_SERVER	-1
+#define _POSIX_THREAD_SPORADIC_SERVER	-1
+
+/* trace.h is not available.  */
+#define _POSIX_TRACE	-1
+#define _POSIX_TRACE_EVENT_FILTER	-1
+#define _POSIX_TRACE_INHERIT	-1
+#define _POSIX_TRACE_LOG	-1
+
+/* Typed memory objects are not available.  */
+#define _POSIX_TYPED_MEMORY_OBJECTS	-1
+
+#endif /* bits/posix_opt.h */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@posix_opt.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@posix_opt.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@pthread_stack_min-dynamic.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@pthread_stack_min-dynamic.h
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@@ -0,0 +1,31 @@
+/* Definition of PTHREAD_STACK_MIN, possibly dynamic.
+   Copyright (C) 2021-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef PTHREAD_STACK_MIN
+# if defined __USE_DYNAMIC_STACK_SIZE && __USE_DYNAMIC_STACK_SIZE
+#  ifndef __ASSEMBLER__
+#   define __SC_THREAD_STACK_MIN_VALUE 75
+__BEGIN_DECLS
+extern long int __sysconf (int __name) __THROW;
+__END_DECLS
+#   define PTHREAD_STACK_MIN __sysconf (__SC_THREAD_STACK_MIN_VALUE)
+#  endif
+# else
+#  include <bits/pthread_stack_min.h>
+# endif
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@pthread_stack_min-dynamic.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@pthread_stack_min-dynamic.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@pthreadtypes-arch.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@pthreadtypes-arch.h
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--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@pthreadtypes-arch.h
@@ -0,0 +1,55 @@
+/* Copyright (C) 2002-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _BITS_PTHREADTYPES_ARCH_H
+#define _BITS_PTHREADTYPES_ARCH_H	1
+
+#include <bits/wordsize.h>
+
+#ifdef __x86_64__
+# if __WORDSIZE == 64
+#  define __SIZEOF_PTHREAD_MUTEX_T 40
+#  define __SIZEOF_PTHREAD_ATTR_T 56
+#  define __SIZEOF_PTHREAD_RWLOCK_T 56
+#  define __SIZEOF_PTHREAD_BARRIER_T 32
+# else
+#  define __SIZEOF_PTHREAD_MUTEX_T 32
+#  define __SIZEOF_PTHREAD_ATTR_T 32
+#  define __SIZEOF_PTHREAD_RWLOCK_T 44
+#  define __SIZEOF_PTHREAD_BARRIER_T 20
+# endif
+#else
+# define __SIZEOF_PTHREAD_MUTEX_T 24
+# define __SIZEOF_PTHREAD_ATTR_T 36
+# define __SIZEOF_PTHREAD_RWLOCK_T 32
+# define __SIZEOF_PTHREAD_BARRIER_T 20
+#endif
+#define __SIZEOF_PTHREAD_MUTEXATTR_T 4
+#define __SIZEOF_PTHREAD_COND_T 48
+#define __SIZEOF_PTHREAD_CONDATTR_T 4
+#define __SIZEOF_PTHREAD_RWLOCKATTR_T 8
+#define __SIZEOF_PTHREAD_BARRIERATTR_T 4
+
+#define __LOCK_ALIGNMENT
+#define __ONCE_ALIGNMENT
+
+#ifndef __x86_64__
+/* Extra attributes for the cleanup functions.  */
+# define __cleanup_fct_attribute __attribute__ ((__regparm__ (1)))
+#endif
+
+#endif	/* bits/pthreadtypes.h */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@pthreadtypes-arch.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@pthreadtypes-arch.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@pthreadtypes.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@pthreadtypes.h
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--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@pthreadtypes.h
@@ -0,0 +1,121 @@
+/* Declaration of common pthread types for all architectures.
+   Copyright (C) 2017-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _BITS_PTHREADTYPES_COMMON_H
+# define _BITS_PTHREADTYPES_COMMON_H	1
+
+/* For internal mutex and condition variable definitions.  */
+#include <bits/thread-shared-types.h>
+
+/* Thread identifiers.  The structure of the attribute type is not
+   exposed on purpose.  */
+typedef unsigned long int pthread_t;
+
+
+/* Data structures for mutex handling.  The structure of the attribute
+   type is not exposed on purpose.  */
+typedef union
+{
+  char __size[__SIZEOF_PTHREAD_MUTEXATTR_T];
+  int __align;
+} pthread_mutexattr_t;
+
+
+/* Data structure for condition variable handling.  The structure of
+   the attribute type is not exposed on purpose.  */
+typedef union
+{
+  char __size[__SIZEOF_PTHREAD_CONDATTR_T];
+  int __align;
+} pthread_condattr_t;
+
+
+/* Keys for thread-specific data */
+typedef unsigned int pthread_key_t;
+
+
+/* Once-only execution */
+typedef int __ONCE_ALIGNMENT pthread_once_t;
+
+
+union pthread_attr_t
+{
+  char __size[__SIZEOF_PTHREAD_ATTR_T];
+  long int __align;
+};
+#ifndef __have_pthread_attr_t
+typedef union pthread_attr_t pthread_attr_t;
+# define __have_pthread_attr_t 1
+#endif
+
+
+typedef union
+{
+  struct __pthread_mutex_s __data;
+  char __size[__SIZEOF_PTHREAD_MUTEX_T];
+  long int __align;
+} pthread_mutex_t;
+
+
+typedef union
+{
+  struct __pthread_cond_s __data;
+  char __size[__SIZEOF_PTHREAD_COND_T];
+  __extension__ long long int __align;
+} pthread_cond_t;
+
+
+#if defined __USE_UNIX98 || defined __USE_XOPEN2K
+/* Data structure for reader-writer lock variable handling.  The
+   structure of the attribute type is deliberately not exposed.  */
+typedef union
+{
+  struct __pthread_rwlock_arch_t __data;
+  char __size[__SIZEOF_PTHREAD_RWLOCK_T];
+  long int __align;
+} pthread_rwlock_t;
+
+typedef union
+{
+  char __size[__SIZEOF_PTHREAD_RWLOCKATTR_T];
+  long int __align;
+} pthread_rwlockattr_t;
+#endif
+
+
+#ifdef __USE_XOPEN2K
+/* POSIX spinlock data type.  */
+typedef volatile int pthread_spinlock_t;
+
+
+/* POSIX barriers data type.  The structure of the type is
+   deliberately not exposed.  */
+typedef union
+{
+  char __size[__SIZEOF_PTHREAD_BARRIER_T];
+  long int __align;
+} pthread_barrier_t;
+
+typedef union
+{
+  char __size[__SIZEOF_PTHREAD_BARRIERATTR_T];
+  int __align;
+} pthread_barrierattr_t;
+#endif
+
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@pthreadtypes.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@pthreadtypes.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@sched.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@sched.h
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--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@sched.h
@@ -0,0 +1,100 @@
+/* Definitions of constants and data structure for POSIX 1003.1b-1993
+   scheduling interface.
+   Copyright (C) 1996-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _BITS_SCHED_H
+#define _BITS_SCHED_H 1
+
+#ifndef _SCHED_H
+# error "Never include <bits/sched.h> directly; use <sched.h> instead."
+#endif
+
+/* Scheduling algorithms.  */
+#define SCHED_OTHER		0
+#define SCHED_FIFO		1
+#define SCHED_RR		2
+#ifdef __USE_GNU
+# define SCHED_BATCH		3
+# define SCHED_ISO		4
+# define SCHED_IDLE		5
+# define SCHED_DEADLINE		6
+
+# define SCHED_RESET_ON_FORK	0x40000000
+#endif
+
+#ifdef __USE_GNU
+/* Cloning flags.  */
+# define CSIGNAL       0x000000ff /* Signal mask to be sent at exit.  */
+# define CLONE_VM      0x00000100 /* Set if VM shared between processes.  */
+# define CLONE_FS      0x00000200 /* Set if fs info shared between processes.  */
+# define CLONE_FILES   0x00000400 /* Set if open files shared between processes.  */
+# define CLONE_SIGHAND 0x00000800 /* Set if signal handlers shared.  */
+# define CLONE_PIDFD   0x00001000 /* Set if a pidfd should be placed
+				     in parent.  */
+# define CLONE_PTRACE  0x00002000 /* Set if tracing continues on the child.  */
+# define CLONE_VFORK   0x00004000 /* Set if the parent wants the child to
+				     wake it up on mm_release.  */
+# define CLONE_PARENT  0x00008000 /* Set if we want to have the same
+				     parent as the cloner.  */
+# define CLONE_THREAD  0x00010000 /* Set to add to same thread group.  */
+# define CLONE_NEWNS   0x00020000 /* Set to create new namespace.  */
+# define CLONE_SYSVSEM 0x00040000 /* Set to shared SVID SEM_UNDO semantics.  */
+# define CLONE_SETTLS  0x00080000 /* Set TLS info.  */
+# define CLONE_PARENT_SETTID 0x00100000 /* Store TID in userlevel buffer
+					   before MM copy.  */
+# define CLONE_CHILD_CLEARTID 0x00200000 /* Register exit futex and memory
+					    location to clear.  */
+# define CLONE_DETACHED 0x00400000 /* Create clone detached.  */
+# define CLONE_UNTRACED 0x00800000 /* Set if the tracing process can't
+				      force CLONE_PTRACE on this clone.  */
+# define CLONE_CHILD_SETTID 0x01000000 /* Store TID in userlevel buffer in
+					  the child.  */
+# define CLONE_NEWCGROUP    0x02000000	/* New cgroup namespace.  */
+# define CLONE_NEWUTS	0x04000000	/* New utsname group.  */
+# define CLONE_NEWIPC	0x08000000	/* New ipcs.  */
+# define CLONE_NEWUSER	0x10000000	/* New user namespace.  */
+# define CLONE_NEWPID	0x20000000	/* New pid namespace.  */
+# define CLONE_NEWNET	0x40000000	/* New network namespace.  */
+# define CLONE_IO	0x80000000	/* Clone I/O context.  */
+#endif
+
+#include <bits/types/struct_sched_param.h>
+
+__BEGIN_DECLS
+
+#ifdef __USE_GNU
+/* Clone current process.  */
+extern int clone (int (*__fn) (void *__arg), void *__child_stack,
+		  int __flags, void *__arg, ...) __THROW;
+
+/* Unshare the specified resources.  */
+extern int unshare (int __flags) __THROW;
+
+/* Get index of currently used CPU.  */
+extern int sched_getcpu (void) __THROW;
+
+/* Get currently used CPU and NUMA node.  */
+extern int getcpu (unsigned int *, unsigned int *) __THROW;
+
+/* Switch process to namespace of type NSTYPE indicated by FD.  */
+extern int setns (int __fd, int __nstype) __THROW;
+#endif
+
+__END_DECLS
+
+#endif /* bits/sched.h */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@sched.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@sched.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@select.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@select.h
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index 0000000000000000000000000000000000000000..9afd878eb6f93b99b49f9dab5667291e35c11455
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@select.h
@@ -0,0 +1,37 @@
+/* Copyright (C) 1997-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _SYS_SELECT_H
+# error "Never use <bits/select.h> directly; include <sys/select.h> instead."
+#endif
+
+
+/* We don't use `memset' because this would require a prototype and
+   the array isn't too big.  */
+#define __FD_ZERO(s) \
+  do {									      \
+    unsigned int __i;							      \
+    fd_set *__arr = (s);						      \
+    for (__i = 0; __i < sizeof (fd_set) / sizeof (__fd_mask); ++__i)	      \
+      __FDS_BITS (__arr)[__i] = 0;					      \
+  } while (0)
+#define __FD_SET(d, s) \
+  ((void) (__FDS_BITS (s)[__FD_ELT(d)] |= __FD_MASK(d)))
+#define __FD_CLR(d, s) \
+  ((void) (__FDS_BITS (s)[__FD_ELT(d)] &= ~__FD_MASK(d)))
+#define __FD_ISSET(d, s) \
+  ((__FDS_BITS (s)[__FD_ELT (d)] & __FD_MASK (d)) != 0)
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@select.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@select.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@setjmp.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@setjmp.h
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@setjmp.h
@@ -0,0 +1,40 @@
+/* Copyright (C) 2001-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+/* Define the machine-dependent type `jmp_buf'.  x86-64 version.  */
+#ifndef _BITS_SETJMP_H
+#define _BITS_SETJMP_H  1
+
+#if !defined _SETJMP_H && !defined _PTHREAD_H
+# error "Never include <bits/setjmp.h> directly; use <setjmp.h> instead."
+#endif
+
+#include <bits/wordsize.h>
+
+#ifndef _ASM
+
+# if __WORDSIZE == 64
+typedef long int __jmp_buf[8];
+# elif defined  __x86_64__
+__extension__ typedef long long int __jmp_buf[8];
+# else
+typedef int __jmp_buf[6];
+# endif
+
+#endif
+
+#endif  /* bits/setjmp.h */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@setjmp.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@setjmp.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@sigaction.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@sigaction.h
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--- /dev/null
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@@ -0,0 +1,83 @@
+/* The proper definitions for Linux's sigaction.
+   Copyright (C) 1993-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _BITS_SIGACTION_H
+#define _BITS_SIGACTION_H 1
+
+#ifndef _SIGNAL_H
+# error "Never include <bits/sigaction.h> directly; use <signal.h> instead."
+#endif
+
+/* Structure describing the action to be taken when a signal arrives.  */
+struct sigaction
+  {
+    /* Signal handler.  */
+#if defined __USE_POSIX199309 || defined __USE_XOPEN_EXTENDED
+    union
+      {
+	/* Used if SA_SIGINFO is not set.  */
+	__sighandler_t sa_handler;
+	/* Used if SA_SIGINFO is set.  */
+	void (*sa_sigaction) (int, siginfo_t *, void *);
+      }
+    __sigaction_handler;
+# define sa_handler	__sigaction_handler.sa_handler
+# define sa_sigaction	__sigaction_handler.sa_sigaction
+#else
+    __sighandler_t sa_handler;
+#endif
+
+    /* Additional set of signals to be blocked.  */
+    __sigset_t sa_mask;
+
+    /* Special flags.  */
+    int sa_flags;
+
+    /* Restore handler.  */
+    void (*sa_restorer) (void);
+  };
+
+/* Bits in `sa_flags'.  */
+#define	SA_NOCLDSTOP  1		 /* Don't send SIGCHLD when children stop.  */
+#define SA_NOCLDWAIT  2		 /* Don't create zombie on child death.  */
+#define SA_SIGINFO    4		 /* Invoke signal-catching function with
+				    three arguments instead of one.  */
+#if defined __USE_XOPEN_EXTENDED || defined __USE_MISC
+# define SA_ONSTACK   0x08000000 /* Use signal stack by using `sa_restorer'. */
+#endif
+#if defined __USE_XOPEN_EXTENDED || defined __USE_XOPEN2K8
+# define SA_RESTART   0x10000000 /* Restart syscall on signal return.  */
+# define SA_NODEFER   0x40000000 /* Don't automatically block the signal when
+				    its handler is being executed.  */
+# define SA_RESETHAND 0x80000000 /* Reset to SIG_DFL on entry to handler.  */
+#endif
+#ifdef __USE_MISC
+# define SA_INTERRUPT 0x20000000 /* Historical no-op.  */
+
+/* Some aliases for the SA_ constants.  */
+# define SA_NOMASK    SA_NODEFER
+# define SA_ONESHOT   SA_RESETHAND
+# define SA_STACK     SA_ONSTACK
+#endif
+
+/* Values for the HOW argument to `sigprocmask'.  */
+#define	SIG_BLOCK     0		 /* Block signals.  */
+#define	SIG_UNBLOCK   1		 /* Unblock signals.  */
+#define	SIG_SETMASK   2		 /* Set the set of blocked signals.  */
+
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@sigaction.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@sigaction.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@sigcontext.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@sigcontext.h
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@sigcontext.h
@@ -0,0 +1,196 @@
+/* Copyright (C) 2002-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	 See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _BITS_SIGCONTEXT_H
+#define _BITS_SIGCONTEXT_H  1
+
+#if !defined _SIGNAL_H && !defined _SYS_UCONTEXT_H
+# error "Never use <bits/sigcontext.h> directly; include <signal.h> instead."
+#endif
+
+#include <bits/types.h>
+
+#define FP_XSTATE_MAGIC1	0x46505853U
+#define FP_XSTATE_MAGIC2	0x46505845U
+#define FP_XSTATE_MAGIC2_SIZE	sizeof (FP_XSTATE_MAGIC2)
+
+struct _fpx_sw_bytes
+{
+  __uint32_t magic1;
+  __uint32_t extended_size;
+  __uint64_t xstate_bv;
+  __uint32_t xstate_size;
+  __uint32_t __glibc_reserved1[7];
+};
+
+struct _fpreg
+{
+  unsigned short significand[4];
+  unsigned short exponent;
+};
+
+struct _fpxreg
+{
+  unsigned short significand[4];
+  unsigned short exponent;
+  unsigned short __glibc_reserved1[3];
+};
+
+struct _xmmreg
+{
+  __uint32_t	element[4];
+};
+
+
+
+#ifndef __x86_64__
+
+struct _fpstate
+{
+  /* Regular FPU environment.  */
+  __uint32_t	cw;
+  __uint32_t		sw;
+  __uint32_t		tag;
+  __uint32_t		ipoff;
+  __uint32_t		cssel;
+  __uint32_t		dataoff;
+  __uint32_t		datasel;
+  struct _fpreg	_st[8];
+  unsigned short status;
+  unsigned short magic;
+
+  /* FXSR FPU environment.  */
+  __uint32_t		_fxsr_env[6];
+  __uint32_t		mxcsr;
+  __uint32_t		__glibc_reserved1;
+  struct _fpxreg	_fxsr_st[8];
+  struct _xmmreg	_xmm[8];
+  __uint32_t		__glibc_reserved2[56];
+};
+
+#ifndef sigcontext_struct
+/* Kernel headers before 2.1.1 define a struct sigcontext_struct, but
+   we need sigcontext.  Some packages have come to rely on
+   sigcontext_struct being defined on 32-bit x86, so define this for
+   their benefit.  */
+# define sigcontext_struct sigcontext
+#endif
+
+#define X86_FXSR_MAGIC		0x0000
+
+struct sigcontext
+{
+  unsigned short gs, __gsh;
+  unsigned short fs, __fsh;
+  unsigned short es, __esh;
+  unsigned short ds, __dsh;
+  unsigned long edi;
+  unsigned long esi;
+  unsigned long ebp;
+  unsigned long esp;
+  unsigned long ebx;
+  unsigned long edx;
+  unsigned long ecx;
+  unsigned long eax;
+  unsigned long trapno;
+  unsigned long err;
+  unsigned long eip;
+  unsigned short cs, __csh;
+  unsigned long eflags;
+  unsigned long esp_at_signal;
+  unsigned short ss, __ssh;
+  struct _fpstate * fpstate;
+  unsigned long oldmask;
+  unsigned long cr2;
+};
+
+#else /* __x86_64__ */
+
+struct _fpstate
+{
+  /* FPU environment matching the 64-bit FXSAVE layout.  */
+  __uint16_t		cwd;
+  __uint16_t		swd;
+  __uint16_t		ftw;
+  __uint16_t		fop;
+  __uint64_t		rip;
+  __uint64_t		rdp;
+  __uint32_t		mxcsr;
+  __uint32_t		mxcr_mask;
+  struct _fpxreg	_st[8];
+  struct _xmmreg	_xmm[16];
+  __uint32_t		__glibc_reserved1[24];
+};
+
+struct sigcontext
+{
+  __uint64_t r8;
+  __uint64_t r9;
+  __uint64_t r10;
+  __uint64_t r11;
+  __uint64_t r12;
+  __uint64_t r13;
+  __uint64_t r14;
+  __uint64_t r15;
+  __uint64_t rdi;
+  __uint64_t rsi;
+  __uint64_t rbp;
+  __uint64_t rbx;
+  __uint64_t rdx;
+  __uint64_t rax;
+  __uint64_t rcx;
+  __uint64_t rsp;
+  __uint64_t rip;
+  __uint64_t eflags;
+  unsigned short cs;
+  unsigned short gs;
+  unsigned short fs;
+  unsigned short __pad0;
+  __uint64_t err;
+  __uint64_t trapno;
+  __uint64_t oldmask;
+  __uint64_t cr2;
+  __extension__ union
+    {
+      struct _fpstate * fpstate;
+      __uint64_t __fpstate_word;
+    };
+  __uint64_t __reserved1 [8];
+};
+
+#endif /* __x86_64__ */
+
+struct _xsave_hdr
+{
+  __uint64_t xstate_bv;
+  __uint64_t __glibc_reserved1[2];
+  __uint64_t __glibc_reserved2[5];
+};
+
+struct _ymmh_state
+{
+  __uint32_t ymmh_space[64];
+};
+
+struct _xstate
+{
+  struct _fpstate fpstate;
+  struct _xsave_hdr xstate_hdr;
+  struct _ymmh_state ymmh;
+};
+
+#endif /* _BITS_SIGCONTEXT_H */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@sigcontext.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@sigcontext.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@sigevent-consts.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@sigevent-consts.h
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@sigevent-consts.h
@@ -0,0 +1,41 @@
+/* sigevent constants.  Linux version.
+   Copyright (C) 1997-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _BITS_SIGEVENT_CONSTS_H
+#define _BITS_SIGEVENT_CONSTS_H 1
+
+#if !defined _SIGNAL_H && !defined _AIO_H
+#error "Don't include <bits/sigevent-consts.h> directly; use <signal.h> instead."
+#endif
+
+/* `sigev_notify' values.  */
+enum
+{
+  SIGEV_SIGNAL = 0,		/* Notify via signal.  */
+# define SIGEV_SIGNAL	SIGEV_SIGNAL
+  SIGEV_NONE,			/* Other notification: meaningless.  */
+# define SIGEV_NONE	SIGEV_NONE
+  SIGEV_THREAD,			/* Deliver via thread creation.  */
+# define SIGEV_THREAD	SIGEV_THREAD
+
+  SIGEV_THREAD_ID = 4		/* Send signal to specific thread.
+				   This is a Linux extension.  */
+#define SIGEV_THREAD_ID	SIGEV_THREAD_ID
+};
+
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@sigevent-consts.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@sigevent-consts.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@siginfo-arch.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@siginfo-arch.h
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@siginfo-arch.h
@@ -0,0 +1,17 @@
+/* Architecture-specific adjustments to siginfo_t.  x86 version.  */
+#ifndef _BITS_SIGINFO_ARCH_H
+#define _BITS_SIGINFO_ARCH_H 1
+
+#if defined __x86_64__ && __WORDSIZE == 32
+/* si_utime and si_stime must be 4 byte aligned for x32 to match the
+   kernel.  We align siginfo_t to 8 bytes so that si_utime and
+   si_stime are actually aligned to 8 bytes since their offsets are
+   multiple of 8 bytes.  Note: with some compilers, the alignment
+   attribute would be ignored if it were put in __SI_CLOCK_T instead
+   of encapsulated in a typedef.  */
+typedef __clock_t __attribute__ ((__aligned__ (4))) __sigchld_clock_t;
+# define __SI_ALIGNMENT __attribute__ ((__aligned__ (8)))
+# define __SI_CLOCK_T __sigchld_clock_t
+#endif
+
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@siginfo-arch.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@siginfo-arch.h.blob
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@@ -0,0 +1,7 @@
+/* Architecture-specific additional siginfo constants.  */
+#ifndef _BITS_SIGINFO_CONSTS_ARCH_H
+#define _BITS_SIGINFO_CONSTS_ARCH_H 1
+
+/* This architecture has no additional siginfo constants.  */
+
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@siginfo-consts-arch.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@siginfo-consts-arch.h.blob
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@@ -0,0 +1,216 @@
+/* siginfo constants.  Linux version.
+   Copyright (C) 1997-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _BITS_SIGINFO_CONSTS_H
+#define _BITS_SIGINFO_CONSTS_H 1
+
+#ifndef _SIGNAL_H
+#error "Don't include <bits/siginfo-consts.h> directly; use <signal.h> instead."
+#endif
+
+/* Most of these constants are uniform across all architectures, but there
+   is one exception.  */
+#include <bits/siginfo-arch.h>
+#ifndef __SI_ASYNCIO_AFTER_SIGIO
+# define __SI_ASYNCIO_AFTER_SIGIO 1
+#endif
+
+/* Values for `si_code'.  Positive values are reserved for kernel-generated
+   signals.  */
+enum
+{
+  SI_ASYNCNL = -60,		/* Sent by asynch name lookup completion.  */
+  SI_DETHREAD = -7,		/* Sent by execve killing subsidiary
+				   threads.  */
+  SI_TKILL,			/* Sent by tkill.  */
+  SI_SIGIO,			/* Sent by queued SIGIO. */
+#if __SI_ASYNCIO_AFTER_SIGIO
+  SI_ASYNCIO,			/* Sent by AIO completion.  */
+  SI_MESGQ,			/* Sent by real time mesq state change.  */
+  SI_TIMER,			/* Sent by timer expiration.  */
+#else
+  SI_MESGQ,
+  SI_TIMER,
+  SI_ASYNCIO,
+#endif
+  SI_QUEUE,			/* Sent by sigqueue.  */
+  SI_USER,			/* Sent by kill, sigsend.  */
+  SI_KERNEL = 0x80		/* Send by kernel.  */
+
+#define SI_ASYNCNL	SI_ASYNCNL
+#define SI_DETHREAD	SI_DETHREAD
+#define SI_TKILL	SI_TKILL
+#define SI_SIGIO	SI_SIGIO
+#define SI_ASYNCIO	SI_ASYNCIO
+#define SI_MESGQ	SI_MESGQ
+#define SI_TIMER	SI_TIMER
+#define SI_ASYNCIO	SI_ASYNCIO
+#define SI_QUEUE	SI_QUEUE
+#define SI_USER		SI_USER
+#define SI_KERNEL	SI_KERNEL
+};
+
+
+# if defined __USE_XOPEN_EXTENDED || defined __USE_XOPEN2K8
+/* `si_code' values for SIGILL signal.  */
+enum
+{
+  ILL_ILLOPC = 1,		/* Illegal opcode.  */
+#  define ILL_ILLOPC	ILL_ILLOPC
+  ILL_ILLOPN,			/* Illegal operand.  */
+#  define ILL_ILLOPN	ILL_ILLOPN
+  ILL_ILLADR,			/* Illegal addressing mode.  */
+#  define ILL_ILLADR	ILL_ILLADR
+  ILL_ILLTRP,			/* Illegal trap. */
+#  define ILL_ILLTRP	ILL_ILLTRP
+  ILL_PRVOPC,			/* Privileged opcode.  */
+#  define ILL_PRVOPC	ILL_PRVOPC
+  ILL_PRVREG,			/* Privileged register.  */
+#  define ILL_PRVREG	ILL_PRVREG
+  ILL_COPROC,			/* Coprocessor error.  */
+#  define ILL_COPROC	ILL_COPROC
+  ILL_BADSTK,			/* Internal stack error.  */
+#  define ILL_BADSTK	ILL_BADSTK
+  ILL_BADIADDR			/* Unimplemented instruction address.  */
+#  define ILL_BADIADDR ILL_BADIADDR
+};
+
+/* `si_code' values for SIGFPE signal.  */
+enum
+{
+  FPE_INTDIV = 1,		/* Integer divide by zero.  */
+#  define FPE_INTDIV	FPE_INTDIV
+  FPE_INTOVF,			/* Integer overflow.  */
+#  define FPE_INTOVF	FPE_INTOVF
+  FPE_FLTDIV,			/* Floating point divide by zero.  */
+#  define FPE_FLTDIV	FPE_FLTDIV
+  FPE_FLTOVF,			/* Floating point overflow.  */
+#  define FPE_FLTOVF	FPE_FLTOVF
+  FPE_FLTUND,			/* Floating point underflow.  */
+#  define FPE_FLTUND	FPE_FLTUND
+  FPE_FLTRES,			/* Floating point inexact result.  */
+#  define FPE_FLTRES	FPE_FLTRES
+  FPE_FLTINV,			/* Floating point invalid operation.  */
+#  define FPE_FLTINV	FPE_FLTINV
+  FPE_FLTSUB,			/* Subscript out of range.  */
+#  define FPE_FLTSUB	FPE_FLTSUB
+  FPE_FLTUNK = 14,		/* Undiagnosed floating-point exception.  */
+#  define FPE_FLTUNK	FPE_FLTUNK
+  FPE_CONDTRAP			/* Trap on condition.  */
+#  define FPE_CONDTRAP	FPE_CONDTRAP
+};
+
+/* `si_code' values for SIGSEGV signal.  */
+enum
+{
+  SEGV_MAPERR = 1,		/* Address not mapped to object.  */
+#  define SEGV_MAPERR	SEGV_MAPERR
+  SEGV_ACCERR,			/* Invalid permissions for mapped object.  */
+#  define SEGV_ACCERR	SEGV_ACCERR
+  SEGV_BNDERR,			/* Bounds checking failure.  */
+#  define SEGV_BNDERR	SEGV_BNDERR
+  SEGV_PKUERR,			/* Protection key checking failure.  */
+#  define SEGV_PKUERR	SEGV_PKUERR
+  SEGV_ACCADI,			/* ADI not enabled for mapped object.  */
+#  define SEGV_ACCADI	SEGV_ACCADI
+  SEGV_ADIDERR,			/* Disrupting MCD error.  */
+#  define SEGV_ADIDERR	SEGV_ADIDERR
+  SEGV_ADIPERR,			/* Precise MCD exception.  */
+#  define SEGV_ADIPERR	SEGV_ADIPERR
+  SEGV_MTEAERR,			/* Asynchronous ARM MTE error.  */
+#  define SEGV_MTEAERR	SEGV_MTEAERR
+  SEGV_MTESERR			/* Synchronous ARM MTE exception.  */
+#  define SEGV_MTESERR	SEGV_MTESERR
+};
+
+/* `si_code' values for SIGBUS signal.  */
+enum
+{
+  BUS_ADRALN = 1,		/* Invalid address alignment.  */
+#  define BUS_ADRALN	BUS_ADRALN
+  BUS_ADRERR,			/* Non-existant physical address.  */
+#  define BUS_ADRERR	BUS_ADRERR
+  BUS_OBJERR,			/* Object specific hardware error.  */
+#  define BUS_OBJERR	BUS_OBJERR
+  BUS_MCEERR_AR,		/* Hardware memory error: action required.  */
+#  define BUS_MCEERR_AR	BUS_MCEERR_AR
+  BUS_MCEERR_AO			/* Hardware memory error: action optional.  */
+#  define BUS_MCEERR_AO	BUS_MCEERR_AO
+};
+# endif
+
+# ifdef __USE_XOPEN_EXTENDED
+/* `si_code' values for SIGTRAP signal.  */
+enum
+{
+  TRAP_BRKPT = 1,		/* Process breakpoint.  */
+#  define TRAP_BRKPT	TRAP_BRKPT
+  TRAP_TRACE,			/* Process trace trap.  */
+#  define TRAP_TRACE	TRAP_TRACE
+  TRAP_BRANCH,			/* Process taken branch trap.  */
+#  define TRAP_BRANCH	TRAP_BRANCH
+  TRAP_HWBKPT,			/* Hardware breakpoint/watchpoint.  */
+#  define TRAP_HWBKPT	TRAP_HWBKPT
+  TRAP_UNK			/* Undiagnosed trap.  */
+#  define TRAP_UNK	TRAP_UNK
+};
+# endif
+
+# if defined __USE_XOPEN_EXTENDED || defined __USE_XOPEN2K8
+/* `si_code' values for SIGCHLD signal.  */
+enum
+{
+  CLD_EXITED = 1,		/* Child has exited.  */
+#  define CLD_EXITED	CLD_EXITED
+  CLD_KILLED,			/* Child was killed.  */
+#  define CLD_KILLED	CLD_KILLED
+  CLD_DUMPED,			/* Child terminated abnormally.  */
+#  define CLD_DUMPED	CLD_DUMPED
+  CLD_TRAPPED,			/* Traced child has trapped.  */
+#  define CLD_TRAPPED	CLD_TRAPPED
+  CLD_STOPPED,			/* Child has stopped.  */
+#  define CLD_STOPPED	CLD_STOPPED
+  CLD_CONTINUED			/* Stopped child has continued.  */
+#  define CLD_CONTINUED	CLD_CONTINUED
+};
+
+/* `si_code' values for SIGPOLL signal.  */
+enum
+{
+  POLL_IN = 1,			/* Data input available.  */
+#  define POLL_IN	POLL_IN
+  POLL_OUT,			/* Output buffers available.  */
+#  define POLL_OUT	POLL_OUT
+  POLL_MSG,			/* Input message available.   */
+#  define POLL_MSG	POLL_MSG
+  POLL_ERR,			/* I/O error.  */
+#  define POLL_ERR	POLL_ERR
+  POLL_PRI,			/* High priority input available.  */
+#  define POLL_PRI	POLL_PRI
+  POLL_HUP			/* Device disconnected.  */
+#  define POLL_HUP	POLL_HUP
+};
+# endif
+
+/* Architectures might also add architecture-specific constants.
+   These are all considered GNU extensions.  */
+#ifdef __USE_GNU
+# include <bits/siginfo-consts-arch.h>
+#endif
+
+#endif
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@signal_ext.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@signal_ext.h
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@signal_ext.h
@@ -0,0 +1,31 @@
+/* System-specific extensions of <signal.h>, Linux version.
+   Copyright (C) 2019-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _SIGNAL_H
+# error "Never include <bits/signal_ext.h> directly; use <signal.h> instead."
+#endif
+
+#ifdef __USE_GNU
+
+/* Send SIGNAL to the thread TID in the thread group (process)
+   identified by TGID.  This function behaves like kill, but also
+   fails with ESRCH if the specified TID does not belong to the
+   specified thread group.  */
+extern int tgkill (__pid_t __tgid, __pid_t __tid, int __signal);
+
+#endif /* __USE_GNU */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@signal_ext.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@signal_ext.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@signum-arch.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@signum-arch.h
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@signum-arch.h
@@ -0,0 +1,64 @@
+/* Signal number definitions.  Linux version.
+   Copyright (C) 1995-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _BITS_SIGNUM_ARCH_H
+#define _BITS_SIGNUM_ARCH_H 1
+
+#ifndef _SIGNAL_H
+#error "Never include <bits/signum-arch.h> directly; use <signal.h> instead."
+#endif
+
+/* Adjustments and additions to the signal number constants for
+   most Linux systems.  */
+
+#define SIGSTKFLT	16	/* Stack fault (obsolete).  */
+#define SIGPWR		30	/* Power failure imminent.  */
+
+/* Historical signals specified by POSIX. */
+#define SIGBUS		 7	/* Bus error.  */
+#define SIGSYS		31	/* Bad system call.  */
+
+/* New(er) POSIX signals (1003.1-2008, 1003.1-2013).  */
+#define SIGURG		23	/* Urgent data is available at a socket.  */
+#define SIGSTOP		19	/* Stop, unblockable.  */
+#define SIGTSTP		20	/* Keyboard stop.  */
+#define SIGCONT		18	/* Continue.  */
+#define SIGCHLD		17	/* Child terminated or stopped.  */
+#define SIGTTIN		21	/* Background read from control terminal.  */
+#define SIGTTOU		22	/* Background write to control terminal.  */
+#define SIGPOLL		29	/* Pollable event occurred (System V).  */
+#define SIGXFSZ		25	/* File size limit exceeded.  */
+#define SIGXCPU		24	/* CPU time limit exceeded.  */
+#define SIGVTALRM	26	/* Virtual timer expired.  */
+#define SIGPROF		27	/* Profiling timer expired.  */
+#define SIGUSR1		10	/* User-defined signal 1.  */
+#define SIGUSR2		12	/* User-defined signal 2.  */
+
+/* Nonstandard signals found in all modern POSIX systems
+   (including both BSD and Linux).  */
+#define SIGWINCH	28	/* Window size change (4.3 BSD, Sun).  */
+
+/* Archaic names for compatibility.  */
+#define SIGIO		SIGPOLL	/* I/O now possible (4.2 BSD).  */
+#define SIGIOT		SIGABRT	/* IOT instruction, abort() on a PDP-11.  */
+#define SIGCLD		SIGCHLD	/* Old System V name */
+
+#define __SIGRTMIN	32
+#define __SIGRTMAX	64
+
+#endif	/* <signal.h> included.  */
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@signum-generic.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@signum-generic.h
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@signum-generic.h
@@ -0,0 +1,81 @@
+/* Signal number constants.  Generic template.
+   Copyright (C) 1991-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef	_BITS_SIGNUM_GENERIC_H
+#define _BITS_SIGNUM_GENERIC_H 1
+
+#ifndef _SIGNAL_H
+#error "Never include <bits/signum-generic.h> directly; use <signal.h> instead."
+#endif
+
+/* Fake signal functions.  */
+
+#define	SIG_ERR	 ((__sighandler_t) -1)	/* Error return.  */
+#define	SIG_DFL	 ((__sighandler_t)  0)	/* Default action.  */
+#define	SIG_IGN	 ((__sighandler_t)  1)	/* Ignore signal.  */
+
+#ifdef __USE_XOPEN
+# define SIG_HOLD ((__sighandler_t) 2)	/* Add signal to hold mask.  */
+#endif
+
+/* We define here all the signal names listed in POSIX (1003.1-2008);
+   as of 1003.1-2013, no additional signals have been added by POSIX.
+   We also define here signal names that historically exist in every
+   real-world POSIX variant (e.g. SIGWINCH).
+
+   Signals in the 1-15 range are defined with their historical numbers.
+   For other signals, we use the BSD numbers.
+   There are two unallocated signal numbers in the 1-31 range: 7 and 29.
+   Signal number 0 is reserved for use as kill(pid, 0), to test whether
+   a process exists without sending it a signal.  */
+
+/* ISO C99 signals.  */
+#define	SIGINT		2	/* Interactive attention signal.  */
+#define	SIGILL		4	/* Illegal instruction.  */
+#define	SIGABRT		6	/* Abnormal termination.  */
+#define	SIGFPE		8	/* Erroneous arithmetic operation.  */
+#define	SIGSEGV		11	/* Invalid access to storage.  */
+#define	SIGTERM		15	/* Termination request.  */
+
+/* Historical signals specified by POSIX. */
+#define	SIGHUP		1	/* Hangup.  */
+#define	SIGQUIT		3	/* Quit.  */
+#define	SIGTRAP		5	/* Trace/breakpoint trap.  */
+#define	SIGKILL		9	/* Killed.  */
+#define	SIGPIPE		13	/* Broken pipe.  */
+#define	SIGALRM		14	/* Alarm clock.  */
+
+/* Archaic names for compatibility.  */
+#define	SIGIO		SIGPOLL	/* I/O now possible (4.2 BSD).  */
+#define	SIGIOT		SIGABRT	/* IOT instruction, abort() on a PDP-11.  */
+#define	SIGCLD		SIGCHLD	/* Old System V name */
+
+/* Not all systems support real-time signals.  bits/signum.h indicates
+   that they are supported by overriding __SIGRTMAX to a value greater
+   than __SIGRTMIN.  These constants give the kernel-level hard limits,
+   but some real-time signals may be used internally by glibc.  Do not
+   use these constants in application code; use SIGRTMIN and SIGRTMAX
+   (defined in signal.h) instead.  */
+
+/* Include system specific bits.  */
+#include <bits/signum-arch.h>
+
+/* Biggest signal number + 1 (including real-time signals).  */
+#define _NSIG		(__SIGRTMAX + 1)
+
+#endif /* bits/signum-generic.h.  */
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@sigstack.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@sigstack.h
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@@ -0,0 +1,32 @@
+/* sigstack, sigaltstack definitions.
+   Copyright (C) 1998-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _BITS_SIGSTACK_H
+#define _BITS_SIGSTACK_H 1
+
+#if !defined _SIGNAL_H && !defined _SYS_UCONTEXT_H
+# error "Never include this file directly.  Use <signal.h> instead"
+#endif
+
+/* Minimum stack size for a signal handler.  */
+#define MINSIGSTKSZ	2048
+
+/* System default stack size.  */
+#define SIGSTKSZ	8192
+
+#endif /* bits/sigstack.h */
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@@ -0,0 +1,33 @@
+/* Definition of MINSIGSTKSZ and SIGSTKSZ.  Linux version.
+   Copyright (C) 2020-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _SIGNAL_H
+# error "Never include <bits/sigstksz.h> directly; use <signal.h> instead."
+#endif
+
+#if defined __USE_DYNAMIC_STACK_SIZE && __USE_DYNAMIC_STACK_SIZE
+# include <unistd.h>
+
+/* Default stack size for a signal handler: sysconf (SC_SIGSTKSZ).  */
+# undef SIGSTKSZ
+# define SIGSTKSZ sysconf (_SC_SIGSTKSZ)
+
+/* Minimum stack size for a signal handler: SIGSTKSZ.  */
+# undef MINSIGSTKSZ
+# define MINSIGSTKSZ SIGSTKSZ
+#endif
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@@ -0,0 +1,44 @@
+/* Signal handling function for threaded programs.
+   Copyright (C) 1998-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public License as
+   published by the Free Software Foundation; either version 2.1 of the
+   License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; see the file COPYING.LIB.  If
+   not, see <https://www.gnu.org/licenses/>.  */
+
+#ifndef _BITS_SIGTHREAD_H
+#define _BITS_SIGTHREAD_H	1
+
+#if !defined _SIGNAL_H && !defined _PTHREAD_H
+# error "Never include this file directly.  Use <signal.h> instead"
+#endif
+
+/* Functions for handling signals. */
+#include <bits/types/__sigset_t.h>
+
+/* Modify the signal mask for the calling thread.  The arguments have
+   the same meaning as for sigprocmask(2). */
+extern int pthread_sigmask (int __how,
+			    const __sigset_t *__restrict __newmask,
+			    __sigset_t *__restrict __oldmask)__THROW;
+
+/* Send signal SIGNO to the given thread. */
+extern int pthread_kill (pthread_t __threadid, int __signo) __THROW;
+
+#ifdef __USE_GNU
+/* Queue signal and data to a thread.  */
+extern int pthread_sigqueue (pthread_t __threadid, int __signo,
+			     const union sigval __value) __THROW;
+#endif
+
+#endif	/* bits/sigthread.h */
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@ss_flags.h
@@ -0,0 +1,35 @@
+/* ss_flags values for stack_t.  Linux version.
+   Copyright (C) 1998-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _BITS_SS_FLAGS_H
+#define _BITS_SS_FLAGS_H 1
+
+#if !defined _SIGNAL_H && !defined _SYS_UCONTEXT_H
+# error "Never include this file directly.  Use <signal.h> instead"
+#endif
+
+/* Possible values for `ss_flags'.  */
+enum
+{
+  SS_ONSTACK = 1,
+#define SS_ONSTACK	SS_ONSTACK
+  SS_DISABLE
+#define SS_DISABLE	SS_DISABLE
+};
+
+#endif /* bits/ss_flags.h */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@ss_flags.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@ss_flags.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@stdint-intn.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@stdint-intn.h
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index 0000000000000000000000000000000000000000..599e2806f8b042bef5956a52c7a1e7e0dbb2cfb3
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@stdint-intn.h
@@ -0,0 +1,29 @@
+/* Define intN_t types.
+   Copyright (C) 2017-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _BITS_STDINT_INTN_H
+#define _BITS_STDINT_INTN_H	1
+
+#include <bits/types.h>
+
+typedef __int8_t int8_t;
+typedef __int16_t int16_t;
+typedef __int32_t int32_t;
+typedef __int64_t int64_t;
+
+#endif /* bits/stdint-intn.h */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@stdint-intn.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@stdint-intn.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@stdint-uintn.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@stdint-uintn.h
new file mode 100644
index 0000000000000000000000000000000000000000..c2846aac3550571c1f1ced63b6c2961d27f20993
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@stdint-uintn.h
@@ -0,0 +1,29 @@
+/* Define uintN_t types.
+   Copyright (C) 2017-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _BITS_STDINT_UINTN_H
+#define _BITS_STDINT_UINTN_H	1
+
+#include <bits/types.h>
+
+typedef __uint8_t uint8_t;
+typedef __uint16_t uint16_t;
+typedef __uint32_t uint32_t;
+typedef __uint64_t uint64_t;
+
+#endif /* bits/stdint-uintn.h */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@stdint-uintn.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@stdint-uintn.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@stdio_lim.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@stdio_lim.h
new file mode 100644
index 0000000000000000000000000000000000000000..4ef3ebb568d77c863b72aa4b1fda1e111bfe77d0
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@stdio_lim.h
@@ -0,0 +1,39 @@
+/* Copyright (C) 1994-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _BITS_STDIO_LIM_H
+#define _BITS_STDIO_LIM_H 1
+
+#ifndef _STDIO_H
+# error "Never include <bits/stdio_lim.h> directly; use <stdio.h> instead."
+#endif
+
+#define L_tmpnam 20
+#define TMP_MAX 238328
+#define FILENAME_MAX 4096
+
+#ifdef __USE_POSIX
+# define L_ctermid 9
+# if !defined __USE_XOPEN2K || defined __USE_GNU
+#  define L_cuserid 9
+# endif
+#endif
+
+#undef  FOPEN_MAX
+#define FOPEN_MAX 16
+
+#endif /* bits/stdio_lim.h */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@stdio_lim.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@stdio_lim.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@stdlib-float.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@stdlib-float.h
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index 0000000000000000000000000000000000000000..b4645dc96cfa6c6c28fe9922de06c4af00bdd2dc
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@stdlib-float.h
@@ -0,0 +1,29 @@
+/* Floating-point inline functions for stdlib.h.
+   Copyright (C) 2012-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _STDLIB_H
+# error "Never use <bits/stdlib-float.h> directly; include <stdlib.h> instead."
+#endif
+
+#ifdef __USE_EXTERN_INLINES
+__extern_inline double
+__NTH (atof (const char *__nptr))
+{
+  return strtod (__nptr, (char **) NULL);
+}
+#endif /* Optimizing and Inlining.  */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@stdlib-float.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@stdlib-float.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@struct_mutex.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@struct_mutex.h
new file mode 100644
index 0000000000000000000000000000000000000000..216127858a30b18f7485f06a727c9226399f40c4
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@struct_mutex.h
@@ -0,0 +1,63 @@
+/* x86 internal mutex struct definitions.
+   Copyright (C) 2019-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#ifndef _THREAD_MUTEX_INTERNAL_H
+#define _THREAD_MUTEX_INTERNAL_H 1
+
+struct __pthread_mutex_s
+{
+  int __lock;
+  unsigned int __count;
+  int __owner;
+#ifdef __x86_64__
+  unsigned int __nusers;
+#endif
+  /* KIND must stay at this position in the structure to maintain
+     binary compatibility with static initializers.  */
+  int __kind;
+#ifdef __x86_64__
+  short __spins;
+  short __elision;
+  __pthread_list_t __list;
+# define __PTHREAD_MUTEX_HAVE_PREV      1
+#else
+  unsigned int __nusers;
+  __extension__ union
+  {
+    struct
+    {
+      short __espins;
+      short __eelision;
+# define __spins __elision_data.__espins
+# define __elision __elision_data.__eelision
+    } __elision_data;
+    __pthread_slist_t __list;
+  };
+# define __PTHREAD_MUTEX_HAVE_PREV      0
+#endif
+};
+
+#ifdef __x86_64__
+# define __PTHREAD_MUTEX_INITIALIZER(__kind) \
+  0, 0, 0, 0, __kind, 0, 0, { 0, 0 }
+#else
+# define __PTHREAD_MUTEX_INITIALIZER(__kind) \
+  0, 0, 0, __kind, 0, { { 0, 0 } }
+#endif
+
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@struct_mutex.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@struct_mutex.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@struct_rwlock.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@struct_rwlock.h
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index 0000000000000000000000000000000000000000..a665d0a3e532a744f84481ca2035f942646f6a68
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@struct_rwlock.h
@@ -0,0 +1,65 @@
+/* x86 internal rwlock struct definitions.
+   Copyright (C) 2019-2022 Free Software Foundation, Inc.
+
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#ifndef _RWLOCK_INTERNAL_H
+#define _RWLOCK_INTERNAL_H
+
+struct __pthread_rwlock_arch_t
+{
+  unsigned int __readers;
+  unsigned int __writers;
+  unsigned int __wrphase_futex;
+  unsigned int __writers_futex;
+  unsigned int __pad3;
+  unsigned int __pad4;
+#ifdef __x86_64__
+  int __cur_writer;
+  int __shared;
+  signed char __rwelision;
+# ifdef  __ILP32__
+  unsigned char __pad1[3];
+#  define __PTHREAD_RWLOCK_ELISION_EXTRA 0, { 0, 0, 0 }
+# else
+  unsigned char __pad1[7];
+#  define __PTHREAD_RWLOCK_ELISION_EXTRA 0, { 0, 0, 0, 0, 0, 0, 0 }
+# endif
+  unsigned long int __pad2;
+  /* FLAGS must stay at this position in the structure to maintain
+     binary compatibility.  */
+  unsigned int __flags;
+#else /* __x86_64__  */
+  /* FLAGS must stay at this position in the structure to maintain
+     binary compatibility.  */
+  unsigned char __flags;
+  unsigned char __shared;
+  signed char __rwelision;
+  unsigned char __pad2;
+  int __cur_writer;
+#endif
+};
+
+#ifdef __x86_64__
+# define __PTHREAD_RWLOCK_INITIALIZER(__flags) \
+  0, 0, 0, 0, 0, 0, 0, 0, __PTHREAD_RWLOCK_ELISION_EXTRA, 0, __flags
+#else
+# define __PTHREAD_RWLOCK_INITIALIZER(__flags) \
+  0, 0, 0, 0, 0, 0, __flags, 0, 0, 0, 0
+#endif
+
+#endif
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@thread-shared-types.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@thread-shared-types.h
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--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@thread-shared-types.h
@@ -0,0 +1,115 @@
+/* Common threading primitives definitions for both POSIX and C11.
+   Copyright (C) 2017-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _THREAD_SHARED_TYPES_H
+#define _THREAD_SHARED_TYPES_H 1
+
+/* Arch-specific definitions.  Each architecture must define the following
+   macros to define the expected sizes of pthread data types:
+
+   __SIZEOF_PTHREAD_ATTR_T        - size of pthread_attr_t.
+   __SIZEOF_PTHREAD_MUTEX_T       - size of pthread_mutex_t.
+   __SIZEOF_PTHREAD_MUTEXATTR_T   - size of pthread_mutexattr_t.
+   __SIZEOF_PTHREAD_COND_T        - size of pthread_cond_t.
+   __SIZEOF_PTHREAD_CONDATTR_T    - size of pthread_condattr_t.
+   __SIZEOF_PTHREAD_RWLOCK_T      - size of pthread_rwlock_t.
+   __SIZEOF_PTHREAD_RWLOCKATTR_T  - size of pthread_rwlockattr_t.
+   __SIZEOF_PTHREAD_BARRIER_T     - size of pthread_barrier_t.
+   __SIZEOF_PTHREAD_BARRIERATTR_T - size of pthread_barrierattr_t.
+
+   The additional macro defines any constraint for the lock alignment
+   inside the thread structures:
+
+   __LOCK_ALIGNMENT - for internal lock/futex usage.
+
+   Same idea but for the once locking primitive:
+
+   __ONCE_ALIGNMENT - for pthread_once_t/once_flag definition.  */
+
+#include <bits/pthreadtypes-arch.h>
+
+#include <bits/atomic_wide_counter.h>
+
+
+/* Common definition of pthread_mutex_t. */
+
+typedef struct __pthread_internal_list
+{
+  struct __pthread_internal_list *__prev;
+  struct __pthread_internal_list *__next;
+} __pthread_list_t;
+
+typedef struct __pthread_internal_slist
+{
+  struct __pthread_internal_slist *__next;
+} __pthread_slist_t;
+
+/* Arch-specific mutex definitions.  A generic implementation is provided
+   by sysdeps/nptl/bits/struct_mutex.h.  If required, an architecture
+   can override it by defining:
+
+   1. struct __pthread_mutex_s (used on both pthread_mutex_t and mtx_t
+      definition).  It should contains at least the internal members
+      defined in the generic version.
+
+   2. __LOCK_ALIGNMENT for any extra attribute for internal lock used with
+      atomic operations.
+
+   3. The macro __PTHREAD_MUTEX_INITIALIZER used for static initialization.
+      It should initialize the mutex internal flag.  */
+
+#include <bits/struct_mutex.h>
+
+/* Arch-sepecific read-write lock definitions.  A generic implementation is
+   provided by struct_rwlock.h.  If required, an architecture can override it
+   by defining:
+
+   1. struct __pthread_rwlock_arch_t (used on pthread_rwlock_t definition).
+      It should contain at least the internal members defined in the
+      generic version.
+
+   2. The macro __PTHREAD_RWLOCK_INITIALIZER used for static initialization.
+      It should initialize the rwlock internal type.  */
+
+#include <bits/struct_rwlock.h>
+
+
+/* Common definition of pthread_cond_t. */
+
+struct __pthread_cond_s
+{
+  __atomic_wide_counter __wseq;
+  __atomic_wide_counter __g1_start;
+  unsigned int __g_refs[2] __LOCK_ALIGNMENT;
+  unsigned int __g_size[2];
+  unsigned int __g1_orig_size;
+  unsigned int __wrefs;
+  unsigned int __g_signals[2];
+};
+
+typedef unsigned int __tss_t;
+typedef unsigned long int __thrd_t;
+
+typedef struct
+{
+  int __data __ONCE_ALIGNMENT;
+} __once_flag;
+
+#define __ONCE_FLAG_INIT { 0 }
+
+#endif /* _THREAD_SHARED_TYPES_H  */
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@time.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@time.h
new file mode 100644
index 0000000000000000000000000000000000000000..efb4a014dff041503d29e399b192665612527ff9
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@time.h
@@ -0,0 +1,93 @@
+/* System-dependent timing definitions.  Linux version.
+   Copyright (C) 1996-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+/*
+ * Never include this file directly; use <time.h> instead.
+ */
+
+#ifndef _BITS_TIME_H
+#define _BITS_TIME_H	1
+
+#include <bits/types.h>
+
+/* ISO/IEC 9899:1999 7.23.1: Components of time
+   The macro `CLOCKS_PER_SEC' is an expression with type `clock_t' that is
+   the number per second of the value returned by the `clock' function.  */
+/* CAE XSH, Issue 4, Version 2: <time.h>
+   The value of CLOCKS_PER_SEC is required to be 1 million on all
+   XSI-conformant systems. */
+#define CLOCKS_PER_SEC  ((__clock_t) 1000000)
+
+#if (!defined __STRICT_ANSI__ || defined __USE_POSIX) \
+   && !defined __USE_XOPEN2K
+/* Even though CLOCKS_PER_SEC has such a strange value CLK_TCK
+   presents the real value for clock ticks per second for the system.  */
+extern long int __sysconf (int);
+# define CLK_TCK ((__clock_t) __sysconf (2))	/* 2 is _SC_CLK_TCK */
+#endif
+
+#ifdef __USE_POSIX199309
+/* Identifier for system-wide realtime clock.  */
+# define CLOCK_REALTIME			0
+/* Monotonic system-wide clock.  */
+# define CLOCK_MONOTONIC		1
+/* High-resolution timer from the CPU.  */
+# define CLOCK_PROCESS_CPUTIME_ID	2
+/* Thread-specific CPU-time clock.  */
+# define CLOCK_THREAD_CPUTIME_ID	3
+/* Monotonic system-wide clock, not adjusted for frequency scaling.  */
+# define CLOCK_MONOTONIC_RAW		4
+/* Identifier for system-wide realtime clock, updated only on ticks.  */
+# define CLOCK_REALTIME_COARSE		5
+/* Monotonic system-wide clock, updated only on ticks.  */
+# define CLOCK_MONOTONIC_COARSE		6
+/* Monotonic system-wide clock that includes time spent in suspension.  */
+# define CLOCK_BOOTTIME			7
+/* Like CLOCK_REALTIME but also wakes suspended system.  */
+# define CLOCK_REALTIME_ALARM		8
+/* Like CLOCK_BOOTTIME but also wakes suspended system.  */
+# define CLOCK_BOOTTIME_ALARM		9
+/* Like CLOCK_REALTIME but in International Atomic Time.  */
+# define CLOCK_TAI			11
+
+/* Flag to indicate time is absolute.  */
+# define TIMER_ABSTIME			1
+#endif
+
+#ifdef __USE_GNU
+# include <bits/timex.h>
+
+__BEGIN_DECLS
+
+/* Tune a POSIX clock.  */
+extern int clock_adjtime (__clockid_t __clock_id, struct timex *__utx) __THROW;
+
+#ifdef __USE_TIME_BITS64
+# if defined(__REDIRECT_NTH)
+extern int __REDIRECT_NTH (clock_adjtime, (__clockid_t __clock_id,
+                                           struct timex *__utx),
+                           __clock_adjtime64);
+# else
+# define clock_adjtime __clock_adjtime64
+# endif
+#endif
+
+__END_DECLS
+#endif /* use GNU */
+
+#endif	/* bits/time.h */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@time.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@time.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@time64.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@time64.h
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--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@time64.h
@@ -0,0 +1,36 @@
+/* bits/time64.h -- underlying types for __time64_t.  Generic version.
+   Copyright (C) 2018-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _BITS_TYPES_H
+# error "Never include <bits/time64.h> directly; use <sys/types.h> instead."
+#endif
+
+#ifndef	_BITS_TIME64_H
+#define	_BITS_TIME64_H	1
+
+/* Define __TIME64_T_TYPE so that it is always a 64-bit type.  */
+
+#if __TIMESIZE == 64
+/* If we already have 64-bit time type then use it.  */
+# define __TIME64_T_TYPE		__TIME_T_TYPE
+#else
+/* Define a 64-bit time type alongsize the 32-bit one.  */
+# define __TIME64_T_TYPE		__SQUAD_TYPE
+#endif
+
+#endif /* bits/time64.h */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@time64.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@time64.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@timesize.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@timesize.h
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--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@timesize.h
@@ -0,0 +1,27 @@
+/* Bit size of the time_t type at glibc build time, x86-64 and x32 case.
+   Copyright (C) 2018-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <bits/wordsize.h>
+
+#if defined __x86_64__ && defined __ILP32__
+/* For x32, time is 64-bit even though word size is 32-bit.  */
+# define __TIMESIZE	64
+#else
+/* For others, time size is word size.  */
+# define __TIMESIZE	__WORDSIZE
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@timesize.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@timesize.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@timex.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@timex.h
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--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@timex.h
@@ -0,0 +1,141 @@
+/* Copyright (C) 1995-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef	_BITS_TIMEX_H
+#define	_BITS_TIMEX_H	1
+
+#include <bits/types.h>
+#include <bits/types/struct_timeval.h>
+
+/* These definitions from linux/timex.h as of 3.18.  */
+
+struct timex
+{
+# if defined __USE_TIME_BITS64 || (__TIMESIZE == 64 && __WORDSIZE == 32)
+  unsigned int modes;          /* mode selector */
+  int :32;                     /* pad */
+  long long offset;            /* time offset (usec) */
+  long long freq;              /* frequency offset (scaled ppm) */
+  long long maxerror;          /* maximum error (usec) */
+  long long esterror;          /* estimated error (usec) */
+  int status;                  /* clock command/status */
+  int :32;                     /* pad */
+  long long constant;          /* pll time constant */
+  long long precision;         /* clock precision (usec) (read only) */
+  long long tolerance;         /* clock frequency tolerance (ppm) (ro) */
+  struct timeval time;     /* (read only, except for ADJ_SETOFFSET) */
+  long long tick;              /* (modified) usecs between clock ticks */
+  long long ppsfreq;           /* pps frequency (scaled ppm) (ro) */
+  long long jitter;            /* pps jitter (us) (ro) */
+  int shift;                   /* interval duration (s) (shift) (ro) */
+  int :32;                     /* pad */
+  long long stabil;            /* pps stability (scaled ppm) (ro) */
+  long long jitcnt;            /* jitter limit exceeded (ro) */
+  long long calcnt;            /* calibration intervals (ro) */
+  long long errcnt;            /* calibration errors (ro) */
+  long long stbcnt;            /* stability limit exceeded (ro) */
+
+  int tai;                     /* TAI offset (ro) */
+
+  int  :32; int  :32; int  :32; int  :32;
+  int  :32; int  :32; int  :32; int  :32;
+  int  :32; int  :32; int  :32;
+# else
+  unsigned int modes;		/* mode selector */
+  __syscall_slong_t offset;	/* time offset (usec) */
+  __syscall_slong_t freq;	/* frequency offset (scaled ppm) */
+  __syscall_slong_t maxerror;	/* maximum error (usec) */
+  __syscall_slong_t esterror;	/* estimated error (usec) */
+  int status;			/* clock command/status */
+  __syscall_slong_t constant;	/* pll time constant */
+  __syscall_slong_t precision;	/* clock precision (usec) (ro) */
+  __syscall_slong_t tolerance;	/* clock frequency tolerance (ppm) (ro) */
+  struct timeval time;		/* (read only, except for ADJ_SETOFFSET) */
+  __syscall_slong_t tick;	/* (modified) usecs between clock ticks */
+  __syscall_slong_t ppsfreq;	/* pps frequency (scaled ppm) (ro) */
+  __syscall_slong_t jitter;	/* pps jitter (us) (ro) */
+  int shift;			/* interval duration (s) (shift) (ro) */
+  __syscall_slong_t stabil;	/* pps stability (scaled ppm) (ro) */
+  __syscall_slong_t jitcnt;	/* jitter limit exceeded (ro) */
+  __syscall_slong_t calcnt;	/* calibration intervals (ro) */
+  __syscall_slong_t errcnt;	/* calibration errors (ro) */
+  __syscall_slong_t stbcnt;	/* stability limit exceeded (ro) */
+
+  int tai;			/* TAI offset (ro) */
+
+  /* ??? */
+  int  :32; int  :32; int  :32; int  :32;
+  int  :32; int  :32; int  :32; int  :32;
+  int  :32; int  :32; int  :32;
+# endif
+};
+
+/* Mode codes (timex.mode) */
+#define ADJ_OFFSET		0x0001	/* time offset */
+#define ADJ_FREQUENCY		0x0002	/* frequency offset */
+#define ADJ_MAXERROR		0x0004	/* maximum time error */
+#define ADJ_ESTERROR		0x0008	/* estimated time error */
+#define ADJ_STATUS		0x0010	/* clock status */
+#define ADJ_TIMECONST		0x0020	/* pll time constant */
+#define ADJ_TAI			0x0080	/* set TAI offset */
+#define ADJ_SETOFFSET		0x0100	/* add 'time' to current time */
+#define ADJ_MICRO		0x1000	/* select microsecond resolution */
+#define ADJ_NANO		0x2000	/* select nanosecond resolution */
+#define ADJ_TICK		0x4000	/* tick value */
+#define ADJ_OFFSET_SINGLESHOT	0x8001	/* old-fashioned adjtime */
+#define ADJ_OFFSET_SS_READ	0xa001	/* read-only adjtime */
+
+/* xntp 3.4 compatibility names */
+#define MOD_OFFSET	ADJ_OFFSET
+#define MOD_FREQUENCY	ADJ_FREQUENCY
+#define MOD_MAXERROR	ADJ_MAXERROR
+#define MOD_ESTERROR	ADJ_ESTERROR
+#define MOD_STATUS	ADJ_STATUS
+#define MOD_TIMECONST	ADJ_TIMECONST
+#define MOD_CLKB	ADJ_TICK
+#define MOD_CLKA	ADJ_OFFSET_SINGLESHOT /* 0x8000 in original */
+#define MOD_TAI		ADJ_TAI
+#define MOD_MICRO	ADJ_MICRO
+#define MOD_NANO	ADJ_NANO
+
+
+/* Status codes (timex.status) */
+#define STA_PLL		0x0001	/* enable PLL updates (rw) */
+#define STA_PPSFREQ	0x0002	/* enable PPS freq discipline (rw) */
+#define STA_PPSTIME	0x0004	/* enable PPS time discipline (rw) */
+#define STA_FLL		0x0008	/* select frequency-lock mode (rw) */
+
+#define STA_INS		0x0010	/* insert leap (rw) */
+#define STA_DEL		0x0020	/* delete leap (rw) */
+#define STA_UNSYNC	0x0040	/* clock unsynchronized (rw) */
+#define STA_FREQHOLD	0x0080	/* hold frequency (rw) */
+
+#define STA_PPSSIGNAL	0x0100	/* PPS signal present (ro) */
+#define STA_PPSJITTER	0x0200	/* PPS signal jitter exceeded (ro) */
+#define STA_PPSWANDER	0x0400	/* PPS signal wander exceeded (ro) */
+#define STA_PPSERROR	0x0800	/* PPS signal calibration error (ro) */
+
+#define STA_CLOCKERR	0x1000	/* clock hardware fault (ro) */
+#define STA_NANO	0x2000	/* resolution (0 = us, 1 = ns) (ro) */
+#define STA_MODE	0x4000	/* mode (0 = PLL, 1 = FLL) (ro) */
+#define STA_CLK		0x8000	/* clock source (0 = A, 1 = B) (ro) */
+
+/* Read-only bits */
+#define STA_RONLY (STA_PPSSIGNAL | STA_PPSJITTER | STA_PPSWANDER \
+    | STA_PPSERROR | STA_CLOCKERR | STA_NANO | STA_MODE | STA_CLK)
+
+#endif /* bits/timex.h */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@timex.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@timex.h.blob
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types.h
@@ -0,0 +1,228 @@
+/* bits/types.h -- definitions of __*_t types underlying *_t types.
+   Copyright (C) 2002-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+/*
+ * Never include this file directly; use <sys/types.h> instead.
+ */
+
+#ifndef	_BITS_TYPES_H
+#define	_BITS_TYPES_H	1
+
+#include <features.h>
+#include <bits/wordsize.h>
+#include <bits/timesize.h>
+
+/* Convenience types.  */
+typedef unsigned char __u_char;
+typedef unsigned short int __u_short;
+typedef unsigned int __u_int;
+typedef unsigned long int __u_long;
+
+/* Fixed-size types, underlying types depend on word size and compiler.  */
+typedef signed char __int8_t;
+typedef unsigned char __uint8_t;
+typedef signed short int __int16_t;
+typedef unsigned short int __uint16_t;
+typedef signed int __int32_t;
+typedef unsigned int __uint32_t;
+#if __WORDSIZE == 64
+typedef signed long int __int64_t;
+typedef unsigned long int __uint64_t;
+#else
+__extension__ typedef signed long long int __int64_t;
+__extension__ typedef unsigned long long int __uint64_t;
+#endif
+
+/* Smallest types with at least a given width.  */
+typedef __int8_t __int_least8_t;
+typedef __uint8_t __uint_least8_t;
+typedef __int16_t __int_least16_t;
+typedef __uint16_t __uint_least16_t;
+typedef __int32_t __int_least32_t;
+typedef __uint32_t __uint_least32_t;
+typedef __int64_t __int_least64_t;
+typedef __uint64_t __uint_least64_t;
+
+/* quad_t is also 64 bits.  */
+#if __WORDSIZE == 64
+typedef long int __quad_t;
+typedef unsigned long int __u_quad_t;
+#else
+__extension__ typedef long long int __quad_t;
+__extension__ typedef unsigned long long int __u_quad_t;
+#endif
+
+/* Largest integral types.  */
+#if __WORDSIZE == 64
+typedef long int __intmax_t;
+typedef unsigned long int __uintmax_t;
+#else
+__extension__ typedef long long int __intmax_t;
+__extension__ typedef unsigned long long int __uintmax_t;
+#endif
+
+
+/* The machine-dependent file <bits/typesizes.h> defines __*_T_TYPE
+   macros for each of the OS types we define below.  The definitions
+   of those macros must use the following macros for underlying types.
+   We define __S<SIZE>_TYPE and __U<SIZE>_TYPE for the signed and unsigned
+   variants of each of the following integer types on this machine.
+
+	16		-- "natural" 16-bit type (always short)
+	32		-- "natural" 32-bit type (always int)
+	64		-- "natural" 64-bit type (long or long long)
+	LONG32		-- 32-bit type, traditionally long
+	QUAD		-- 64-bit type, traditionally long long
+	WORD		-- natural type of __WORDSIZE bits (int or long)
+	LONGWORD	-- type of __WORDSIZE bits, traditionally long
+
+   We distinguish WORD/LONGWORD, 32/LONG32, and 64/QUAD so that the
+   conventional uses of `long' or `long long' type modifiers match the
+   types we define, even when a less-adorned type would be the same size.
+   This matters for (somewhat) portably writing printf/scanf formats for
+   these types, where using the appropriate l or ll format modifiers can
+   make the typedefs and the formats match up across all GNU platforms.  If
+   we used `long' when it's 64 bits where `long long' is expected, then the
+   compiler would warn about the formats not matching the argument types,
+   and the programmer changing them to shut up the compiler would break the
+   program's portability.
+
+   Here we assume what is presently the case in all the GCC configurations
+   we support: long long is always 64 bits, long is always word/address size,
+   and int is always 32 bits.  */
+
+#define	__S16_TYPE		short int
+#define __U16_TYPE		unsigned short int
+#define	__S32_TYPE		int
+#define __U32_TYPE		unsigned int
+#define __SLONGWORD_TYPE	long int
+#define __ULONGWORD_TYPE	unsigned long int
+#if __WORDSIZE == 32
+# define __SQUAD_TYPE		__int64_t
+# define __UQUAD_TYPE		__uint64_t
+# define __SWORD_TYPE		int
+# define __UWORD_TYPE		unsigned int
+# define __SLONG32_TYPE		long int
+# define __ULONG32_TYPE		unsigned long int
+# define __S64_TYPE		__int64_t
+# define __U64_TYPE		__uint64_t
+/* We want __extension__ before typedef's that use nonstandard base types
+   such as `long long' in C89 mode.  */
+# define __STD_TYPE		__extension__ typedef
+#elif __WORDSIZE == 64
+# define __SQUAD_TYPE		long int
+# define __UQUAD_TYPE		unsigned long int
+# define __SWORD_TYPE		long int
+# define __UWORD_TYPE		unsigned long int
+# define __SLONG32_TYPE		int
+# define __ULONG32_TYPE		unsigned int
+# define __S64_TYPE		long int
+# define __U64_TYPE		unsigned long int
+/* No need to mark the typedef with __extension__.   */
+# define __STD_TYPE		typedef
+#else
+# error
+#endif
+#include <bits/typesizes.h>	/* Defines __*_T_TYPE macros.  */
+#include <bits/time64.h>	/* Defines __TIME*_T_TYPE macros.  */
+
+
+__STD_TYPE __DEV_T_TYPE __dev_t;	/* Type of device numbers.  */
+__STD_TYPE __UID_T_TYPE __uid_t;	/* Type of user identifications.  */
+__STD_TYPE __GID_T_TYPE __gid_t;	/* Type of group identifications.  */
+__STD_TYPE __INO_T_TYPE __ino_t;	/* Type of file serial numbers.  */
+__STD_TYPE __INO64_T_TYPE __ino64_t;	/* Type of file serial numbers (LFS).*/
+__STD_TYPE __MODE_T_TYPE __mode_t;	/* Type of file attribute bitmasks.  */
+__STD_TYPE __NLINK_T_TYPE __nlink_t;	/* Type of file link counts.  */
+__STD_TYPE __OFF_T_TYPE __off_t;	/* Type of file sizes and offsets.  */
+__STD_TYPE __OFF64_T_TYPE __off64_t;	/* Type of file sizes and offsets (LFS).  */
+__STD_TYPE __PID_T_TYPE __pid_t;	/* Type of process identifications.  */
+__STD_TYPE __FSID_T_TYPE __fsid_t;	/* Type of file system IDs.  */
+__STD_TYPE __CLOCK_T_TYPE __clock_t;	/* Type of CPU usage counts.  */
+__STD_TYPE __RLIM_T_TYPE __rlim_t;	/* Type for resource measurement.  */
+__STD_TYPE __RLIM64_T_TYPE __rlim64_t;	/* Type for resource measurement (LFS).  */
+__STD_TYPE __ID_T_TYPE __id_t;		/* General type for IDs.  */
+__STD_TYPE __TIME_T_TYPE __time_t;	/* Seconds since the Epoch.  */
+__STD_TYPE __USECONDS_T_TYPE __useconds_t; /* Count of microseconds.  */
+__STD_TYPE __SUSECONDS_T_TYPE __suseconds_t; /* Signed count of microseconds.  */
+__STD_TYPE __SUSECONDS64_T_TYPE __suseconds64_t;
+
+__STD_TYPE __DADDR_T_TYPE __daddr_t;	/* The type of a disk address.  */
+__STD_TYPE __KEY_T_TYPE __key_t;	/* Type of an IPC key.  */
+
+/* Clock ID used in clock and timer functions.  */
+__STD_TYPE __CLOCKID_T_TYPE __clockid_t;
+
+/* Timer ID returned by `timer_create'.  */
+__STD_TYPE __TIMER_T_TYPE __timer_t;
+
+/* Type to represent block size.  */
+__STD_TYPE __BLKSIZE_T_TYPE __blksize_t;
+
+/* Types from the Large File Support interface.  */
+
+/* Type to count number of disk blocks.  */
+__STD_TYPE __BLKCNT_T_TYPE __blkcnt_t;
+__STD_TYPE __BLKCNT64_T_TYPE __blkcnt64_t;
+
+/* Type to count file system blocks.  */
+__STD_TYPE __FSBLKCNT_T_TYPE __fsblkcnt_t;
+__STD_TYPE __FSBLKCNT64_T_TYPE __fsblkcnt64_t;
+
+/* Type to count file system nodes.  */
+__STD_TYPE __FSFILCNT_T_TYPE __fsfilcnt_t;
+__STD_TYPE __FSFILCNT64_T_TYPE __fsfilcnt64_t;
+
+/* Type of miscellaneous file system fields.  */
+__STD_TYPE __FSWORD_T_TYPE __fsword_t;
+
+__STD_TYPE __SSIZE_T_TYPE __ssize_t; /* Type of a byte count, or error.  */
+
+/* Signed long type used in system calls.  */
+__STD_TYPE __SYSCALL_SLONG_TYPE __syscall_slong_t;
+/* Unsigned long type used in system calls.  */
+__STD_TYPE __SYSCALL_ULONG_TYPE __syscall_ulong_t;
+
+/* These few don't really vary by system, they always correspond
+   to one of the other defined types.  */
+typedef __off64_t __loff_t;	/* Type of file sizes and offsets (LFS).  */
+typedef char *__caddr_t;
+
+/* Duplicates info from stdint.h but this is used in unistd.h.  */
+__STD_TYPE __SWORD_TYPE __intptr_t;
+
+/* Duplicate info from sys/socket.h.  */
+__STD_TYPE __U32_TYPE __socklen_t;
+
+/* C99: An integer type that can be accessed as an atomic entity,
+   even in the presence of asynchronous interrupts.
+   It is not currently necessary for this to be machine-specific.  */
+typedef int __sig_atomic_t;
+
+/* Seconds since the Epoch, visible to user code when time_t is too
+   narrow only for consistency with the old way of widening too-narrow
+   types.  User code should never use __time64_t.  */
+#if __TIMESIZE == 64 && defined __LIBC
+# define __time64_t __time_t
+#elif __TIMESIZE != 64
+__STD_TYPE __TIME64_T_TYPE __time64_t;
+#endif
+
+#undef __STD_TYPE
+
+#endif /* bits/types.h */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@FILE.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@FILE.h
new file mode 100644
index 0000000000000000000000000000000000000000..f2682632090ba3e7f2caa1736394cbb235ceab0c
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@FILE.h
@@ -0,0 +1,9 @@
+#ifndef __FILE_defined
+#define __FILE_defined 1
+
+struct _IO_FILE;
+
+/* The opaque type of streams.  This is the definition used elsewhere.  */
+typedef struct _IO_FILE FILE;
+
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@FILE.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@FILE.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@__FILE.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@__FILE.h
new file mode 100644
index 0000000000000000000000000000000000000000..06dd79bc831bb06a6267a36ad2d62beccd7900b2
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@__FILE.h
@@ -0,0 +1,7 @@
+#ifndef ____FILE_defined
+#define ____FILE_defined 1
+
+struct _IO_FILE;
+typedef struct _IO_FILE __FILE;
+
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@__FILE.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@__FILE.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@__fpos64_t.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@__fpos64_t.h
new file mode 100644
index 0000000000000000000000000000000000000000..06a6891154fff74e1ddb6245f4a0467b09c617c5
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@__fpos64_t.h
@@ -0,0 +1,16 @@
+#ifndef _____fpos64_t_defined
+#define _____fpos64_t_defined 1
+
+#include <bits/types.h>
+#include <bits/types/__mbstate_t.h>
+
+/* The tag name of this struct is _G_fpos64_t to preserve historic
+   C++ mangled names for functions taking fpos_t and/or fpos64_t
+   arguments.  That name should not be used in new code.  */
+typedef struct _G_fpos64_t
+{
+  __off64_t __pos;
+  __mbstate_t __state;
+} __fpos64_t;
+
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@__fpos64_t.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@__fpos64_t.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@__fpos_t.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@__fpos_t.h
new file mode 100644
index 0000000000000000000000000000000000000000..bb04576651b9097b3027e4299cc30c88f334535f
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@__fpos_t.h
@@ -0,0 +1,16 @@
+#ifndef _____fpos_t_defined
+#define _____fpos_t_defined 1
+
+#include <bits/types.h>
+#include <bits/types/__mbstate_t.h>
+
+/* The tag name of this struct is _G_fpos_t to preserve historic
+   C++ mangled names for functions taking fpos_t arguments.
+   That name should not be used in new code.  */
+typedef struct _G_fpos_t
+{
+  __off_t __pos;
+  __mbstate_t __state;
+} __fpos_t;
+
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@__fpos_t.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@__fpos_t.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@__locale_t.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@__locale_t.h
new file mode 100644
index 0000000000000000000000000000000000000000..a578eaea53672170a1dfb8a373ef4d2468856568
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@__locale_t.h
@@ -0,0 +1,43 @@
+/* Definition of struct __locale_struct and __locale_t.
+   Copyright (C) 1997-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _BITS_TYPES___LOCALE_T_H
+#define _BITS_TYPES___LOCALE_T_H 1
+
+/* POSIX.1-2008: the locale_t type, representing a locale context
+   (implementation-namespace version).  This type should be treated
+   as opaque by applications; some details are exposed for the sake of
+   efficiency in e.g. ctype functions.  */
+
+struct __locale_struct
+{
+  /* Note: LC_ALL is not a valid index into this array.  */
+  struct __locale_data *__locales[13]; /* 13 = __LC_LAST. */
+
+  /* To increase the speed of this solution we add some special members.  */
+  const unsigned short int *__ctype_b;
+  const int *__ctype_tolower;
+  const int *__ctype_toupper;
+
+  /* Note: LC_ALL is not a valid index into this array.  */
+  const char *__names[13];
+};
+
+typedef struct __locale_struct *__locale_t;
+
+#endif /* bits/types/__locale_t.h */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@__locale_t.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@__locale_t.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@__mbstate_t.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@__mbstate_t.h
new file mode 100644
index 0000000000000000000000000000000000000000..1d8a4e28d1b62a2bfeba837fe18422cd106e6ddf
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@__mbstate_t.h
@@ -0,0 +1,23 @@
+#ifndef ____mbstate_t_defined
+#define ____mbstate_t_defined 1
+
+/* Integral type unchanged by default argument promotions that can
+   hold any value corresponding to members of the extended character
+   set, as well as at least one value that does not correspond to any
+   member of the extended character set.  */
+#ifndef __WINT_TYPE__
+# define __WINT_TYPE__ unsigned int
+#endif
+
+/* Conversion state information.  */
+typedef struct
+{
+  int __count;
+  union
+  {
+    __WINT_TYPE__ __wch;
+    char __wchb[4];
+  } __value;		/* Value so far.  */
+} __mbstate_t;
+
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@__mbstate_t.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@__mbstate_t.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@__sigset_t.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@__sigset_t.h
new file mode 100644
index 0000000000000000000000000000000000000000..e2f18acf30f43496567b1511456089dcd1798425
--- /dev/null
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@@ -0,0 +1,10 @@
+#ifndef ____sigset_t_defined
+#define ____sigset_t_defined
+
+#define _SIGSET_NWORDS (1024 / (8 * sizeof (unsigned long int)))
+typedef struct
+{
+  unsigned long int __val[_SIGSET_NWORDS];
+} __sigset_t;
+
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@__sigset_t.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@__sigset_t.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@__sigval_t.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@__sigval_t.h
new file mode 100644
index 0000000000000000000000000000000000000000..5746ab97da47c42aca19e911ca98c4627aba9111
--- /dev/null
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@@ -0,0 +1,41 @@
+/* Define __sigval_t.
+   Copyright (C) 1997-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef ____sigval_t_defined
+#define ____sigval_t_defined
+
+/* Type for data associated with a signal.  */
+#ifdef __USE_POSIX199309
+union sigval
+{
+  int sival_int;
+  void *sival_ptr;
+};
+
+typedef union sigval __sigval_t;
+#else
+union __sigval
+{
+  int __sival_int;
+  void *__sival_ptr;
+};
+
+typedef union __sigval __sigval_t;
+#endif
+
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@__sigval_t.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@__sigval_t.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@clock_t.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@clock_t.h
new file mode 100644
index 0000000000000000000000000000000000000000..ce97248f8856164bef6a2949ef88a289c9046e96
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@clock_t.h
@@ -0,0 +1,9 @@
+#ifndef __clock_t_defined
+#define __clock_t_defined 1
+
+#include <bits/types.h>
+
+/* Returned by `clock'.  */
+typedef __clock_t clock_t;
+
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@clock_t.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@clock_t.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@clockid_t.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@clockid_t.h
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index 0000000000000000000000000000000000000000..b17c7da85315c67196341cad4afd8a253115f149
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@clockid_t.h
@@ -0,0 +1,9 @@
+#ifndef __clockid_t_defined
+#define __clockid_t_defined 1
+
+#include <bits/types.h>
+
+/* Clock ID used in clock and timer functions.  */
+typedef __clockid_t clockid_t;
+
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@clockid_t.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@clockid_t.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@cookie_io_functions_t.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@cookie_io_functions_t.h
new file mode 100644
index 0000000000000000000000000000000000000000..dc59536bdcfbca98f7e21194e464641675b6de8e
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@cookie_io_functions_t.h
@@ -0,0 +1,63 @@
+/* Copyright (C) 1991-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef __cookie_io_functions_t_defined
+#define __cookie_io_functions_t_defined 1
+
+#include <bits/types.h>
+
+/* Functions to do I/O and file management for a stream.  */
+
+/* Read NBYTES bytes from COOKIE into a buffer pointed to by BUF.
+   Return number of bytes read.  */
+typedef __ssize_t cookie_read_function_t (void *__cookie, char *__buf,
+                                          size_t __nbytes);
+
+/* Write NBYTES bytes pointed to by BUF to COOKIE.  Write all NBYTES bytes
+   unless there is an error.  Return number of bytes written.  If
+   there is an error, return 0 and do not write anything.  If the file
+   has been opened for append (__mode.__append set), then set the file
+   pointer to the end of the file and then do the write; if not, just
+   write at the current file pointer.  */
+typedef __ssize_t cookie_write_function_t (void *__cookie, const char *__buf,
+                                           size_t __nbytes);
+
+/* Move COOKIE's file position to *POS bytes from the
+   beginning of the file (if W is SEEK_SET),
+   the current position (if W is SEEK_CUR),
+   or the end of the file (if W is SEEK_END).
+   Set *POS to the new file position.
+   Returns zero if successful, nonzero if not.  */
+typedef int cookie_seek_function_t (void *__cookie, __off64_t *__pos, int __w);
+
+/* Close COOKIE.  */
+typedef int cookie_close_function_t (void *__cookie);
+
+/* The structure with the cookie function pointers.
+   The tag name of this struct is _IO_cookie_io_functions_t to
+   preserve historic C++ mangled names for functions taking
+   cookie_io_functions_t arguments.  That name should not be used in
+   new code.  */
+typedef struct _IO_cookie_io_functions_t
+{
+  cookie_read_function_t *read;		/* Read bytes.  */
+  cookie_write_function_t *write;	/* Write bytes.  */
+  cookie_seek_function_t *seek;		/* Seek/tell file position.  */
+  cookie_close_function_t *close;	/* Close file.  */
+} cookie_io_functions_t;
+
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@cookie_io_functions_t.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@cookie_io_functions_t.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@error_t.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@error_t.h
new file mode 100644
index 0000000000000000000000000000000000000000..5c31746a0d085e7281f3f584c9480a0fe8c58f9f
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@error_t.h
@@ -0,0 +1,24 @@
+/* Define error_t.
+   Copyright (C) 1991-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef __error_t_defined
+# define __error_t_defined 1
+
+typedef int error_t;
+
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@error_t.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@error_t.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@locale_t.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@locale_t.h
new file mode 100644
index 0000000000000000000000000000000000000000..0ebc9f08b7abda1c15b5342dc5a8e0ea0ec972dc
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@locale_t.h
@@ -0,0 +1,26 @@
+/* Definition of locale_t.
+   Copyright (C) 2017-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _BITS_TYPES_LOCALE_T_H
+#define _BITS_TYPES_LOCALE_T_H 1
+
+#include <bits/types/__locale_t.h>
+
+typedef __locale_t locale_t;
+
+#endif /* bits/types/locale_t.h */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@locale_t.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@locale_t.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@mbstate_t.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@mbstate_t.h
new file mode 100644
index 0000000000000000000000000000000000000000..8d1baa5c3b22d779e5c696d7153e33b9161b5081
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@mbstate_t.h
@@ -0,0 +1,8 @@
+#ifndef __mbstate_t_defined
+#define __mbstate_t_defined 1
+
+#include <bits/types/__mbstate_t.h>
+
+typedef __mbstate_t mbstate_t;
+
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@mbstate_t.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@mbstate_t.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@sig_atomic_t.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@sig_atomic_t.h
new file mode 100644
index 0000000000000000000000000000000000000000..47eaa28311e16965b3ef1bccac724e48b18c3cb5
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@sig_atomic_t.h
@@ -0,0 +1,10 @@
+#ifndef __sig_atomic_t_defined
+#define __sig_atomic_t_defined 1
+
+#include <bits/types.h>
+
+/* An integral type that can be modified atomically, without the
+   possibility of a signal arriving in the middle of the operation.  */
+typedef __sig_atomic_t sig_atomic_t;
+
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@sig_atomic_t.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@sig_atomic_t.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@sigevent_t.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@sigevent_t.h
new file mode 100644
index 0000000000000000000000000000000000000000..e8b28de7e3ff6b8bf47661235edbebed511534d8
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@sigevent_t.h
@@ -0,0 +1,48 @@
+#ifndef __sigevent_t_defined
+#define __sigevent_t_defined 1
+
+#include <bits/wordsize.h>
+#include <bits/types.h>
+#include <bits/types/__sigval_t.h>
+
+#define __SIGEV_MAX_SIZE	64
+#if __WORDSIZE == 64
+# define __SIGEV_PAD_SIZE	((__SIGEV_MAX_SIZE / sizeof (int)) - 4)
+#else
+# define __SIGEV_PAD_SIZE	((__SIGEV_MAX_SIZE / sizeof (int)) - 3)
+#endif
+
+/* Forward declaration.  */
+#ifndef __have_pthread_attr_t
+typedef union pthread_attr_t pthread_attr_t;
+# define __have_pthread_attr_t	1
+#endif
+
+/* Structure to transport application-defined values with signals.  */
+typedef struct sigevent
+  {
+    __sigval_t sigev_value;
+    int sigev_signo;
+    int sigev_notify;
+
+    union
+      {
+	int _pad[__SIGEV_PAD_SIZE];
+
+	/* When SIGEV_SIGNAL and SIGEV_THREAD_ID set, LWP ID of the
+	   thread to receive the signal.  */
+	__pid_t _tid;
+
+	struct
+	  {
+	    void (*_function) (__sigval_t);	/* Function to start.  */
+	    pthread_attr_t *_attribute;		/* Thread attributes.  */
+	  } _sigev_thread;
+      } _sigev_un;
+  } sigevent_t;
+
+/* POSIX names to access some of the members.  */
+#define sigev_notify_function   _sigev_un._sigev_thread._function
+#define sigev_notify_attributes _sigev_un._sigev_thread._attribute
+
+#endif
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@siginfo_t.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@siginfo_t.h
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index 0000000000000000000000000000000000000000..43c4e009a44faef57558093d248a715f75759f89
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@siginfo_t.h
@@ -0,0 +1,151 @@
+#ifndef __siginfo_t_defined
+#define __siginfo_t_defined 1
+
+#include <bits/wordsize.h>
+#include <bits/types.h>
+#include <bits/types/__sigval_t.h>
+
+#define __SI_MAX_SIZE	128
+#if __WORDSIZE == 64
+# define __SI_PAD_SIZE	((__SI_MAX_SIZE / sizeof (int)) - 4)
+#else
+# define __SI_PAD_SIZE	((__SI_MAX_SIZE / sizeof (int)) - 3)
+#endif
+
+/* Some fields of siginfo_t have architecture-specific variations.  */
+#include <bits/siginfo-arch.h>
+#ifndef __SI_ALIGNMENT
+# define __SI_ALIGNMENT		/* nothing */
+#endif
+#ifndef __SI_BAND_TYPE
+# define __SI_BAND_TYPE		long int
+#endif
+#ifndef __SI_CLOCK_T
+# define __SI_CLOCK_T		__clock_t
+#endif
+#ifndef __SI_ERRNO_THEN_CODE
+# define __SI_ERRNO_THEN_CODE	1
+#endif
+#ifndef __SI_HAVE_SIGSYS
+# define __SI_HAVE_SIGSYS	1
+#endif
+#ifndef __SI_SIGFAULT_ADDL
+# define __SI_SIGFAULT_ADDL	/* nothing */
+#endif
+
+typedef struct
+  {
+    int si_signo;		/* Signal number.  */
+#if __SI_ERRNO_THEN_CODE
+    int si_errno;		/* If non-zero, an errno value associated with
+				   this signal, as defined in <errno.h>.  */
+    int si_code;		/* Signal code.  */
+#else
+    int si_code;
+    int si_errno;
+#endif
+#if __WORDSIZE == 64
+    int __pad0;			/* Explicit padding.  */
+#endif
+
+    union
+      {
+	int _pad[__SI_PAD_SIZE];
+
+	 /* kill().  */
+	struct
+	  {
+	    __pid_t si_pid;	/* Sending process ID.  */
+	    __uid_t si_uid;	/* Real user ID of sending process.  */
+	  } _kill;
+
+	/* POSIX.1b timers.  */
+	struct
+	  {
+	    int si_tid;		/* Timer ID.  */
+	    int si_overrun;	/* Overrun count.  */
+	    __sigval_t si_sigval;	/* Signal value.  */
+	  } _timer;
+
+	/* POSIX.1b signals.  */
+	struct
+	  {
+	    __pid_t si_pid;	/* Sending process ID.  */
+	    __uid_t si_uid;	/* Real user ID of sending process.  */
+	    __sigval_t si_sigval;	/* Signal value.  */
+	  } _rt;
+
+	/* SIGCHLD.  */
+	struct
+	  {
+	    __pid_t si_pid;	/* Which child.	 */
+	    __uid_t si_uid;	/* Real user ID of sending process.  */
+	    int si_status;	/* Exit value or signal.  */
+	    __SI_CLOCK_T si_utime;
+	    __SI_CLOCK_T si_stime;
+	  } _sigchld;
+
+	/* SIGILL, SIGFPE, SIGSEGV, SIGBUS.  */
+	struct
+	  {
+	    void *si_addr;	    /* Faulting insn/memory ref.  */
+	    __SI_SIGFAULT_ADDL
+	    short int si_addr_lsb;  /* Valid LSB of the reported address.  */
+	    union
+	      {
+		/* used when si_code=SEGV_BNDERR */
+		struct
+		  {
+		    void *_lower;
+		    void *_upper;
+		  } _addr_bnd;
+		/* used when si_code=SEGV_PKUERR */
+		__uint32_t _pkey;
+	      } _bounds;
+	  } _sigfault;
+
+	/* SIGPOLL.  */
+	struct
+	  {
+	    __SI_BAND_TYPE si_band;	/* Band event for SIGPOLL.  */
+	    int si_fd;
+	  } _sigpoll;
+
+	/* SIGSYS.  */
+#if __SI_HAVE_SIGSYS
+	struct
+	  {
+	    void *_call_addr;	/* Calling user insn.  */
+	    int _syscall;	/* Triggering system call number.  */
+	    unsigned int _arch; /* AUDIT_ARCH_* of syscall.  */
+	  } _sigsys;
+#endif
+      } _sifields;
+  } siginfo_t __SI_ALIGNMENT;
+
+
+/* X/Open requires some more fields with fixed names.  */
+#define si_pid		_sifields._kill.si_pid
+#define si_uid		_sifields._kill.si_uid
+#define si_timerid	_sifields._timer.si_tid
+#define si_overrun	_sifields._timer.si_overrun
+#define si_status	_sifields._sigchld.si_status
+#define si_utime	_sifields._sigchld.si_utime
+#define si_stime	_sifields._sigchld.si_stime
+#define si_value	_sifields._rt.si_sigval
+#define si_int		_sifields._rt.si_sigval.sival_int
+#define si_ptr		_sifields._rt.si_sigval.sival_ptr
+#define si_addr		_sifields._sigfault.si_addr
+#define si_addr_lsb	_sifields._sigfault.si_addr_lsb
+#define si_lower	_sifields._sigfault._bounds._addr_bnd._lower
+#define si_upper	_sifields._sigfault._bounds._addr_bnd._upper
+#define si_pkey		_sifields._sigfault._bounds._pkey
+#define si_band		_sifields._sigpoll.si_band
+#define si_fd		_sifields._sigpoll.si_fd
+#if __SI_HAVE_SIGSYS
+# define si_call_addr	_sifields._sigsys._call_addr
+# define si_syscall	_sifields._sigsys._syscall
+# define si_arch	_sifields._sigsys._arch
+#endif
+
+#endif
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@sigset_t.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@sigset_t.h
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@@ -0,0 +1,9 @@
+#ifndef __sigset_t_defined
+#define __sigset_t_defined 1
+
+#include <bits/types/__sigset_t.h>
+
+/* A set of signals to be blocked, unblocked, or waited for.  */
+typedef __sigset_t sigset_t;
+
+#endif
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@@ -0,0 +1,18 @@
+#ifndef __sigval_t_defined
+#define __sigval_t_defined
+
+#include <bits/types/__sigval_t.h>
+
+/* To avoid sigval_t (not a standard type name) having C++ name
+   mangling depending on whether the selected standard includes union
+   sigval, it should not be defined at all when using a standard for
+   which the sigval name is not reserved; in that case, headers should
+   not include <bits/types/sigval_t.h> and should use only the
+   internal __sigval_t name.  */
+#ifndef __USE_POSIX199309
+# error "sigval_t defined for standard not including union sigval"
+#endif
+
+typedef __sigval_t sigval_t;
+
+#endif
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@stack_t.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@stack_t.h
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@stack_t.h
@@ -0,0 +1,33 @@
+/* Define stack_t.  Linux version.
+   Copyright (C) 1998-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef __stack_t_defined
+#define __stack_t_defined 1
+
+#define __need_size_t
+#include <stddef.h>
+
+/* Structure describing a signal stack.  */
+typedef struct
+  {
+    void *ss_sp;
+    int ss_flags;
+    size_t ss_size;
+  } stack_t;
+
+#endif
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@struct_FILE.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@struct_FILE.h
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--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@struct_FILE.h
@@ -0,0 +1,120 @@
+/* Copyright (C) 1991-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef __struct_FILE_defined
+#define __struct_FILE_defined 1
+
+/* Caution: The contents of this file are not part of the official
+   stdio.h API.  However, much of it is part of the official *binary*
+   interface, and therefore cannot be changed.  */
+
+#if defined _IO_USE_OLD_IO_FILE && !defined _LIBC
+# error "_IO_USE_OLD_IO_FILE should only be defined when building libc itself"
+#endif
+
+#if defined _IO_lock_t_defined && !defined _LIBC
+# error "_IO_lock_t_defined should only be defined when building libc itself"
+#endif
+
+#include <bits/types.h>
+
+struct _IO_FILE;
+struct _IO_marker;
+struct _IO_codecvt;
+struct _IO_wide_data;
+
+/* During the build of glibc itself, _IO_lock_t will already have been
+   defined by internal headers.  */
+#ifndef _IO_lock_t_defined
+typedef void _IO_lock_t;
+#endif
+
+/* The tag name of this struct is _IO_FILE to preserve historic
+   C++ mangled names for functions taking FILE* arguments.
+   That name should not be used in new code.  */
+struct _IO_FILE
+{
+  int _flags;		/* High-order word is _IO_MAGIC; rest is flags. */
+
+  /* The following pointers correspond to the C++ streambuf protocol. */
+  char *_IO_read_ptr;	/* Current read pointer */
+  char *_IO_read_end;	/* End of get area. */
+  char *_IO_read_base;	/* Start of putback+get area. */
+  char *_IO_write_base;	/* Start of put area. */
+  char *_IO_write_ptr;	/* Current put pointer. */
+  char *_IO_write_end;	/* End of put area. */
+  char *_IO_buf_base;	/* Start of reserve area. */
+  char *_IO_buf_end;	/* End of reserve area. */
+
+  /* The following fields are used to support backing up and undo. */
+  char *_IO_save_base; /* Pointer to start of non-current get area. */
+  char *_IO_backup_base;  /* Pointer to first valid character of backup area */
+  char *_IO_save_end; /* Pointer to end of non-current get area. */
+
+  struct _IO_marker *_markers;
+
+  struct _IO_FILE *_chain;
+
+  int _fileno;
+  int _flags2;
+  __off_t _old_offset; /* This used to be _offset but it's too small.  */
+
+  /* 1+column number of pbase(); 0 is unknown. */
+  unsigned short _cur_column;
+  signed char _vtable_offset;
+  char _shortbuf[1];
+
+  _IO_lock_t *_lock;
+#ifdef _IO_USE_OLD_IO_FILE
+};
+
+struct _IO_FILE_complete
+{
+  struct _IO_FILE _file;
+#endif
+  __off64_t _offset;
+  /* Wide character stream stuff.  */
+  struct _IO_codecvt *_codecvt;
+  struct _IO_wide_data *_wide_data;
+  struct _IO_FILE *_freeres_list;
+  void *_freeres_buf;
+  size_t __pad5;
+  int _mode;
+  /* Make sure we don't get into trouble again.  */
+  char _unused2[15 * sizeof (int) - 4 * sizeof (void *) - sizeof (size_t)];
+};
+
+/* These macros are used by bits/stdio.h and internal headers.  */
+#define __getc_unlocked_body(_fp)					\
+  (__glibc_unlikely ((_fp)->_IO_read_ptr >= (_fp)->_IO_read_end)	\
+   ? __uflow (_fp) : *(unsigned char *) (_fp)->_IO_read_ptr++)
+
+#define __putc_unlocked_body(_ch, _fp)					\
+  (__glibc_unlikely ((_fp)->_IO_write_ptr >= (_fp)->_IO_write_end)	\
+   ? __overflow (_fp, (unsigned char) (_ch))				\
+   : (unsigned char) (*(_fp)->_IO_write_ptr++ = (_ch)))
+
+#define _IO_EOF_SEEN 0x0010
+#define __feof_unlocked_body(_fp) (((_fp)->_flags & _IO_EOF_SEEN) != 0)
+
+#define _IO_ERR_SEEN 0x0020
+#define __ferror_unlocked_body(_fp) (((_fp)->_flags & _IO_ERR_SEEN) != 0)
+
+#define _IO_USER_LOCK 0x8000
+/* Many more flag bits are defined internally.  */
+
+#endif
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@struct___jmp_buf_tag.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@struct___jmp_buf_tag.h
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@struct___jmp_buf_tag.h
@@ -0,0 +1,37 @@
+/* Define struct __jmp_buf_tag.
+   Copyright (C) 1991-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef	__jmp_buf_tag_defined
+#define	__jmp_buf_tag_defined 1
+
+#include <bits/setjmp.h>		/* Get `__jmp_buf'.  */
+#include <bits/types/__sigset_t.h>
+
+/* Calling environment, plus possibly a saved signal mask.  */
+struct __jmp_buf_tag
+  {
+    /* NOTE: The machine-dependent definitions of `__sigsetjmp'
+       assume that a `jmp_buf' begins with a `__jmp_buf' and that
+       `__mask_was_saved' follows it.  Do not move these members
+       or add others before it.  */
+    __jmp_buf __jmpbuf;		/* Calling environment.  */
+    int __mask_was_saved;	/* Saved the signal mask?  */
+    __sigset_t __saved_mask;	/* Saved signal mask.  */
+  };
+
+#endif
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@struct_itimerspec.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@struct_itimerspec.h
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@@ -0,0 +1,14 @@
+#ifndef __itimerspec_defined
+#define __itimerspec_defined 1
+
+#include <bits/types.h>
+#include <bits/types/struct_timespec.h>
+
+/* POSIX.1b structure for timer start values and intervals.  */
+struct itimerspec
+  {
+    struct timespec it_interval;
+    struct timespec it_value;
+  };
+
+#endif
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@@ -0,0 +1,28 @@
+/* Sched parameter structure.  Generic version.
+   Copyright (C) 1996-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library;  if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _BITS_TYPES_STRUCT_SCHED_PARAM
+#define _BITS_TYPES_STRUCT_SCHED_PARAM 1
+
+/* Data structure to describe a process' schedulability.  */
+struct sched_param
+{
+  int sched_priority;
+};
+
+#endif /* bits/types/struct_sched_param.h */
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@struct_sigstack.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@struct_sigstack.h
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--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@struct_sigstack.h
@@ -0,0 +1,29 @@
+/* Define struct sigstack.
+   Copyright (C) 1998-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef __sigstack_defined
+#define __sigstack_defined 1
+
+/* Structure describing a signal stack (obsolete).  */
+struct sigstack
+  {
+    void *ss_sp;		/* Signal stack pointer.  */
+    int ss_onstack;		/* Nonzero if executing on this stack.  */
+  };
+
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@struct_sigstack.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@struct_sigstack.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@struct_timespec.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@struct_timespec.h
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@struct_timespec.h
@@ -0,0 +1,33 @@
+/* NB: Include guard matches what <linux/time.h> uses.  */
+#ifndef _STRUCT_TIMESPEC
+#define _STRUCT_TIMESPEC 1
+
+#include <bits/types.h>
+#include <bits/endian.h>
+#include <bits/types/time_t.h>
+
+/* POSIX.1b structure for a time value.  This is like a `struct timeval' but
+   has nanoseconds instead of microseconds.  */
+struct timespec
+{
+#ifdef __USE_TIME_BITS64
+  __time64_t tv_sec;		/* Seconds.  */
+#else
+  __time_t tv_sec;		/* Seconds.  */
+#endif
+#if __WORDSIZE == 64 \
+  || (defined __SYSCALL_WORDSIZE && __SYSCALL_WORDSIZE == 64) \
+  || (__TIMESIZE == 32 && !defined __USE_TIME_BITS64)
+  __syscall_slong_t tv_nsec;	/* Nanoseconds.  */
+#else
+# if __BYTE_ORDER == __BIG_ENDIAN
+  int: 32;           /* Padding.  */
+  long int tv_nsec;  /* Nanoseconds.  */
+# else
+  long int tv_nsec;  /* Nanoseconds.  */
+  int: 32;           /* Padding.  */
+# endif
+#endif
+};
+
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@struct_timespec.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@struct_timespec.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@struct_timeval.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@struct_timeval.h
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--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@struct_timeval.h
@@ -0,0 +1,18 @@
+#ifndef __timeval_defined
+#define __timeval_defined 1
+
+#include <bits/types.h>
+
+/* A time value that is accurate to the nearest
+   microsecond but also has a range of years.  */
+struct timeval
+{
+#ifdef __USE_TIME_BITS64
+  __time64_t tv_sec;		/* Seconds.  */
+  __suseconds64_t tv_usec;	/* Microseconds.  */
+#else
+  __time_t tv_sec;		/* Seconds.  */
+  __suseconds_t tv_usec;	/* Microseconds.  */
+#endif
+};
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@struct_timeval.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@struct_timeval.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@struct_tm.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@struct_tm.h
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@struct_tm.h
@@ -0,0 +1,28 @@
+#ifndef __struct_tm_defined
+#define __struct_tm_defined 1
+
+#include <bits/types.h>
+
+/* ISO C `broken-down time' structure.  */
+struct tm
+{
+  int tm_sec;			/* Seconds.	[0-60] (1 leap second) */
+  int tm_min;			/* Minutes.	[0-59] */
+  int tm_hour;			/* Hours.	[0-23] */
+  int tm_mday;			/* Day.		[1-31] */
+  int tm_mon;			/* Month.	[0-11] */
+  int tm_year;			/* Year	- 1900.  */
+  int tm_wday;			/* Day of week.	[0-6] */
+  int tm_yday;			/* Days in year.[0-365]	*/
+  int tm_isdst;			/* DST.		[-1/0/1]*/
+
+# ifdef	__USE_MISC
+  long int tm_gmtoff;		/* Seconds east of UTC.  */
+  const char *tm_zone;		/* Timezone abbreviation.  */
+# else
+  long int __tm_gmtoff;		/* Seconds east of UTC.  */
+  const char *__tm_zone;	/* Timezone abbreviation.  */
+# endif
+};
+
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@struct_tm.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@struct_tm.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@time_t.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@time_t.h
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--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@time_t.h
@@ -0,0 +1,13 @@
+#ifndef __time_t_defined
+#define __time_t_defined 1
+
+#include <bits/types.h>
+
+/* Returned by `time'.  */
+#ifdef __USE_TIME_BITS64
+typedef __time64_t time_t;
+#else
+typedef __time_t time_t;
+#endif
+
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@time_t.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@time_t.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@timer_t.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@timer_t.h
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index 0000000000000000000000000000000000000000..d71a4130e213131dd58dc1e3c7c53fbe59db47a8
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@timer_t.h
@@ -0,0 +1,9 @@
+#ifndef __timer_t_defined
+#define __timer_t_defined 1
+
+#include <bits/types.h>
+
+/* Timer ID returned by `timer_create'.  */
+typedef __timer_t timer_t;
+
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@timer_t.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@timer_t.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@wint_t.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@wint_t.h
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index 0000000000000000000000000000000000000000..fbd63dbc84959491013cb6213022f8874083e29a
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@wint_t.h
@@ -0,0 +1,23 @@
+#ifndef __wint_t_defined
+#define __wint_t_defined 1
+
+/* Some versions of stddef.h provide wint_t, even though neither the
+   C nor C++ standards, nor POSIX, specifies this.  We assume that
+   stddef.h will define the macro _WINT_T if and only if it provides
+   wint_t, and conversely, that it will avoid providing wint_t if
+   _WINT_T is already defined.  */
+#ifndef _WINT_T
+#define _WINT_T 1
+
+/* Integral type unchanged by default argument promotions that can
+   hold any value corresponding to members of the extended character
+   set, as well as at least one value that does not correspond to any
+   member of the extended character set.  */
+#ifndef __WINT_TYPE__
+# define __WINT_TYPE__ unsigned int
+#endif
+
+typedef __WINT_TYPE__ wint_t;
+
+#endif /* _WINT_T */
+#endif /* bits/types/wint_t.h */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@wint_t.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@types@wint_t.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@typesizes.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@typesizes.h
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index 0000000000000000000000000000000000000000..20e70232784068fd15c9d470c3404de8ecdea403
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@typesizes.h
@@ -0,0 +1,106 @@
+/* bits/typesizes.h -- underlying types for *_t.  Linux/x86-64 version.
+   Copyright (C) 2012-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _BITS_TYPES_H
+# error "Never include <bits/typesizes.h> directly; use <sys/types.h> instead."
+#endif
+
+#ifndef	_BITS_TYPESIZES_H
+#define	_BITS_TYPESIZES_H	1
+
+/* See <bits/types.h> for the meaning of these macros.  This file exists so
+   that <bits/types.h> need not vary across different GNU platforms.  */
+
+/* X32 kernel interface is 64-bit.  */
+#if defined __x86_64__ && defined __ILP32__
+# define __SYSCALL_SLONG_TYPE	__SQUAD_TYPE
+# define __SYSCALL_ULONG_TYPE	__UQUAD_TYPE
+#else
+# define __SYSCALL_SLONG_TYPE	__SLONGWORD_TYPE
+# define __SYSCALL_ULONG_TYPE	__ULONGWORD_TYPE
+#endif
+
+#define __DEV_T_TYPE		__UQUAD_TYPE
+#define __UID_T_TYPE		__U32_TYPE
+#define __GID_T_TYPE		__U32_TYPE
+#define __INO_T_TYPE		__SYSCALL_ULONG_TYPE
+#define __INO64_T_TYPE		__UQUAD_TYPE
+#define __MODE_T_TYPE		__U32_TYPE
+#ifdef __x86_64__
+# define __NLINK_T_TYPE		__SYSCALL_ULONG_TYPE
+# define __FSWORD_T_TYPE	__SYSCALL_SLONG_TYPE
+#else
+# define __NLINK_T_TYPE		__UWORD_TYPE
+# define __FSWORD_T_TYPE	__SWORD_TYPE
+#endif
+#define __OFF_T_TYPE		__SYSCALL_SLONG_TYPE
+#define __OFF64_T_TYPE		__SQUAD_TYPE
+#define __PID_T_TYPE		__S32_TYPE
+#define __RLIM_T_TYPE		__SYSCALL_ULONG_TYPE
+#define __RLIM64_T_TYPE		__UQUAD_TYPE
+#define __BLKCNT_T_TYPE		__SYSCALL_SLONG_TYPE
+#define __BLKCNT64_T_TYPE	__SQUAD_TYPE
+#define __FSBLKCNT_T_TYPE	__SYSCALL_ULONG_TYPE
+#define __FSBLKCNT64_T_TYPE	__UQUAD_TYPE
+#define __FSFILCNT_T_TYPE	__SYSCALL_ULONG_TYPE
+#define __FSFILCNT64_T_TYPE	__UQUAD_TYPE
+#define __ID_T_TYPE		__U32_TYPE
+#define __CLOCK_T_TYPE		__SYSCALL_SLONG_TYPE
+#define __TIME_T_TYPE		__SYSCALL_SLONG_TYPE
+#define __USECONDS_T_TYPE	__U32_TYPE
+#define __SUSECONDS_T_TYPE	__SYSCALL_SLONG_TYPE
+#define __SUSECONDS64_T_TYPE	__SQUAD_TYPE
+#define __DADDR_T_TYPE		__S32_TYPE
+#define __KEY_T_TYPE		__S32_TYPE
+#define __CLOCKID_T_TYPE	__S32_TYPE
+#define __TIMER_T_TYPE		void *
+#define __BLKSIZE_T_TYPE	__SYSCALL_SLONG_TYPE
+#define __FSID_T_TYPE		struct { int __val[2]; }
+#define __SSIZE_T_TYPE		__SWORD_TYPE
+#define __CPU_MASK_TYPE 	__SYSCALL_ULONG_TYPE
+
+#ifdef __x86_64__
+/* Tell the libc code that off_t and off64_t are actually the same type
+   for all ABI purposes, even if possibly expressed as different base types
+   for C type-checking purposes.  */
+# define __OFF_T_MATCHES_OFF64_T	1
+
+/* Same for ino_t and ino64_t.  */
+# define __INO_T_MATCHES_INO64_T	1
+
+/* And for __rlim_t and __rlim64_t.  */
+# define __RLIM_T_MATCHES_RLIM64_T	1
+
+/* And for fsblkcnt_t, fsblkcnt64_t, fsfilcnt_t and fsfilcnt64_t.  */
+# define __STATFS_MATCHES_STATFS64  1
+
+/* And for getitimer, setitimer and rusage  */
+# define __KERNEL_OLD_TIMEVAL_MATCHES_TIMEVAL64 1
+#else
+# define __RLIM_T_MATCHES_RLIM64_T	0
+
+# define __STATFS_MATCHES_STATFS64  0
+
+# define __KERNEL_OLD_TIMEVAL_MATCHES_TIMEVAL64 0
+#endif
+
+/* Number of descriptors that can fit in an `fd_set'.  */
+#define __FD_SETSIZE		1024
+
+
+#endif /* bits/typesizes.h */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@typesizes.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@typesizes.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@uintn-identity.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@uintn-identity.h
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@@ -0,0 +1,50 @@
+/* Inline functions to return unsigned integer values unchanged.
+   Copyright (C) 2017-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#if !defined _NETINET_IN_H && !defined _ENDIAN_H
+# error "Never use <bits/uintn-identity.h> directly; include <netinet/in.h> or <endian.h> instead."
+#endif
+
+#ifndef _BITS_UINTN_IDENTITY_H
+#define _BITS_UINTN_IDENTITY_H 1
+
+#include <bits/types.h>
+
+/* These inline functions are to ensure the appropriate type
+   conversions and associated diagnostics from macros that convert to
+   a given endianness.  */
+
+static __inline __uint16_t
+__uint16_identity (__uint16_t __x)
+{
+  return __x;
+}
+
+static __inline __uint32_t
+__uint32_identity (__uint32_t __x)
+{
+  return __x;
+}
+
+static __inline __uint64_t
+__uint64_identity (__uint64_t __x)
+{
+  return __x;
+}
+
+#endif /* _BITS_UINTN_IDENTITY_H.  */
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@uio_lim.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@uio_lim.h
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--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@uio_lim.h
@@ -0,0 +1,32 @@
+/* Implementation limits related to sys/uio.h - Linux version.
+   Copyright (C) 2017-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _BITS_UIO_LIM_H
+#define _BITS_UIO_LIM_H 1
+
+/* Maximum length of the 'struct iovec' array in a single call to
+   readv or writev.
+
+   This macro has different values in different kernel versions.  The
+   latest versions of the kernel use 1024 and this is good choice.  Since
+   the C library implementation of readv/writev is able to emulate the
+   functionality even if the currently running kernel does not support
+   this large value the readv/writev call will not fail because of this.  */
+#define __IOV_MAX	1024
+
+#endif
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@unistd_ext.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@unistd_ext.h
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--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@unistd_ext.h
@@ -0,0 +1,50 @@
+/* System-specific extensions of <unistd.h>, Linux version.
+   Copyright (C) 2019-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _UNISTD_H
+# error "Never include <bits/unistd_ext.h> directly; use <unistd.h> instead."
+#endif
+
+#ifdef __USE_GNU
+
+/* Return the kernel thread ID (TID) of the current thread.  The
+   returned value is not subject to caching.  Most Linux system calls
+   accept a TID in place of a PID.  Using the TID to change properties
+   of a thread that has been created using pthread_create can lead to
+   undefined behavior (comparable to manipulating file descriptors
+   directly that have not been created explicitly).  Note that a TID
+   uniquely identifies a thread only while this thread is running; a
+   TID can be reused once a thread has exited, even if the thread is
+   not detached and has not been joined.  */
+extern __pid_t gettid (void) __THROW;
+
+#ifdef __has_include
+# if __has_include ("linux/close_range.h")
+#  include "linux/close_range.h"
+# endif
+#endif
+/* Unshare the file descriptor table before closing file descriptors.  */
+#ifndef CLOSE_RANGE_UNSHARE
+# define CLOSE_RANGE_UNSHARE (1U << 1)
+#endif
+/* Set the FD_CLOEXEC bit instead of closing the file descriptor.  */
+#ifndef CLOSE_RANGE_CLOEXEC
+# define CLOSE_RANGE_CLOEXEC (1U << 2)
+#endif
+
+#endif /* __USE_GNU  */
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@waitflags.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@waitflags.h
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--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@waitflags.h
@@ -0,0 +1,39 @@
+/* Definitions of flag bits for `waitpid' et al.
+   Copyright (C) 1992-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#if !defined _SYS_WAIT_H && !defined _STDLIB_H
+# error "Never include <bits/waitflags.h> directly; use <sys/wait.h> instead."
+#endif
+
+
+/* Bits in the third argument to `waitpid'.  */
+#define	WNOHANG		1	/* Don't block waiting.  */
+#define	WUNTRACED	2	/* Report status of stopped children.  */
+
+/* Bits in the fourth argument to `waitid'.  */
+#if defined __USE_XOPEN_EXTENDED || defined __USE_XOPEN2K8
+# define WSTOPPED	2	/* Report stopped child (same as WUNTRACED). */
+# define WEXITED	4	/* Report dead child.  */
+# define WCONTINUED	8	/* Report continued child.  */
+# define WNOWAIT	0x01000000 /* Don't reap, just poll status.  */
+#endif
+
+#define __WNOTHREAD     0x20000000 /* Don't wait on children of other threads
+				      in this group */
+#define __WALL		0x40000000 /* Wait for any child.  */
+#define __WCLONE	0x80000000 /* Wait for cloned process.  */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@waitflags.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@waitflags.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@waitstatus.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@waitstatus.h
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--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@waitstatus.h
@@ -0,0 +1,59 @@
+/* Definitions of status bits for `wait' et al.
+   Copyright (C) 1992-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#if !defined _SYS_WAIT_H && !defined _STDLIB_H
+# error "Never include <bits/waitstatus.h> directly; use <sys/wait.h> instead."
+#endif
+
+
+/* Everything extant so far uses these same bits.  */
+
+
+/* If WIFEXITED(STATUS), the low-order 8 bits of the status.  */
+#define	__WEXITSTATUS(status)	(((status) & 0xff00) >> 8)
+
+/* If WIFSIGNALED(STATUS), the terminating signal.  */
+#define	__WTERMSIG(status)	((status) & 0x7f)
+
+/* If WIFSTOPPED(STATUS), the signal that stopped the child.  */
+#define	__WSTOPSIG(status)	__WEXITSTATUS(status)
+
+/* Nonzero if STATUS indicates normal termination.  */
+#define	__WIFEXITED(status)	(__WTERMSIG(status) == 0)
+
+/* Nonzero if STATUS indicates termination by a signal.  */
+#define __WIFSIGNALED(status) \
+  (((signed char) (((status) & 0x7f) + 1) >> 1) > 0)
+
+/* Nonzero if STATUS indicates the child is stopped.  */
+#define	__WIFSTOPPED(status)	(((status) & 0xff) == 0x7f)
+
+/* Nonzero if STATUS indicates the child continued after a stop.  We only
+   define this if <bits/waitflags.h> provides the WCONTINUED flag bit.  */
+#ifdef WCONTINUED
+# define __WIFCONTINUED(status)	((status) == __W_CONTINUED)
+#endif
+
+/* Nonzero if STATUS indicates the child dumped core.  */
+#define	__WCOREDUMP(status)	((status) & __WCOREFLAG)
+
+/* Macros for constructing status values.  */
+#define	__W_EXITCODE(ret, sig)	((ret) << 8 | (sig))
+#define	__W_STOPCODE(sig)	((sig) << 8 | 0x7f)
+#define __W_CONTINUED		0xffff
+#define	__WCOREFLAG		0x80
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@waitstatus.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@waitstatus.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@wchar.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@wchar.h
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@wchar.h
@@ -0,0 +1,49 @@
+/* wchar_t type related definitions.
+   Copyright (C) 2000-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _BITS_WCHAR_H
+#define _BITS_WCHAR_H	1
+
+/* The fallback definitions, for when __WCHAR_MAX__ or __WCHAR_MIN__
+   are not defined, give the right value and type as long as both int
+   and wchar_t are 32-bit types.  Adding L'\0' to a constant value
+   ensures that the type is correct; it is necessary to use (L'\0' +
+   0) rather than just L'\0' so that the type in C++ is the promoted
+   version of wchar_t rather than the distinct wchar_t type itself.
+   Because wchar_t in preprocessor #if expressions is treated as
+   intmax_t or uintmax_t, the expression (L'\0' - 1) would have the
+   wrong value for WCHAR_MAX in such expressions and so cannot be used
+   to define __WCHAR_MAX in the unsigned case.  */
+
+#ifdef __WCHAR_MAX__
+# define __WCHAR_MAX	__WCHAR_MAX__
+#elif L'\0' - 1 > 0
+# define __WCHAR_MAX	(0xffffffffu + L'\0')
+#else
+# define __WCHAR_MAX	(0x7fffffff + L'\0')
+#endif
+
+#ifdef __WCHAR_MIN__
+# define __WCHAR_MIN	__WCHAR_MIN__
+#elif L'\0' - 1 > 0
+# define __WCHAR_MIN	(L'\0' + 0)
+#else
+# define __WCHAR_MIN	(-__WCHAR_MAX - 1)
+#endif
+
+#endif	/* bits/wchar.h */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@wchar.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@wchar.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@wctype-wchar.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@wctype-wchar.h
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@@ -0,0 +1,173 @@
+/* Copyright (C) 1996-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+/*
+ *	ISO C99 Standard: 7.25
+ *	Wide character classification and mapping utilities  <wctype.h>
+ */
+
+#ifndef _BITS_WCTYPE_WCHAR_H
+#define _BITS_WCTYPE_WCHAR_H 1
+
+#if !defined _WCTYPE_H && !defined _WCHAR_H
+#error "Never include <bits/wctype-wchar.h> directly; include <wctype.h> or <wchar.h> instead."
+#endif
+
+#include <bits/types.h>
+#include <bits/types/wint_t.h>
+
+/* The definitions in this header are specified to appear in <wctype.h>
+   in ISO C99, but in <wchar.h> in Unix98.  _GNU_SOURCE follows C99.  */
+
+/* Scalar type that can hold values which represent locale-specific
+   character classifications.  */
+typedef unsigned long int wctype_t;
+
+# ifndef _ISwbit
+/* The characteristics are stored always in network byte order (big
+   endian).  We define the bit value interpretations here dependent on the
+   machine's byte order.  */
+
+#  include <bits/endian.h>
+#  if __BYTE_ORDER == __BIG_ENDIAN
+#   define _ISwbit(bit)	(1 << (bit))
+#  else /* __BYTE_ORDER == __LITTLE_ENDIAN */
+#   define _ISwbit(bit)	\
+	((bit) < 8 ? (int) ((1UL << (bit)) << 24)			      \
+	 : ((bit) < 16 ? (int) ((1UL << (bit)) << 8)			      \
+	    : ((bit) < 24 ? (int) ((1UL << (bit)) >> 8)			      \
+	       : (int) ((1UL << (bit)) >> 24))))
+#  endif
+
+enum
+{
+  __ISwupper = 0,			/* UPPERCASE.  */
+  __ISwlower = 1,			/* lowercase.  */
+  __ISwalpha = 2,			/* Alphabetic.  */
+  __ISwdigit = 3,			/* Numeric.  */
+  __ISwxdigit = 4,			/* Hexadecimal numeric.  */
+  __ISwspace = 5,			/* Whitespace.  */
+  __ISwprint = 6,			/* Printing.  */
+  __ISwgraph = 7,			/* Graphical.  */
+  __ISwblank = 8,			/* Blank (usually SPC and TAB).  */
+  __ISwcntrl = 9,			/* Control character.  */
+  __ISwpunct = 10,			/* Punctuation.  */
+  __ISwalnum = 11,			/* Alphanumeric.  */
+
+  _ISwupper = _ISwbit (__ISwupper),	/* UPPERCASE.  */
+  _ISwlower = _ISwbit (__ISwlower),	/* lowercase.  */
+  _ISwalpha = _ISwbit (__ISwalpha),	/* Alphabetic.  */
+  _ISwdigit = _ISwbit (__ISwdigit),	/* Numeric.  */
+  _ISwxdigit = _ISwbit (__ISwxdigit),	/* Hexadecimal numeric.  */
+  _ISwspace = _ISwbit (__ISwspace),	/* Whitespace.  */
+  _ISwprint = _ISwbit (__ISwprint),	/* Printing.  */
+  _ISwgraph = _ISwbit (__ISwgraph),	/* Graphical.  */
+  _ISwblank = _ISwbit (__ISwblank),	/* Blank (usually SPC and TAB).  */
+  _ISwcntrl = _ISwbit (__ISwcntrl),	/* Control character.  */
+  _ISwpunct = _ISwbit (__ISwpunct),	/* Punctuation.  */
+  _ISwalnum = _ISwbit (__ISwalnum)	/* Alphanumeric.  */
+};
+# endif /* Not _ISwbit  */
+
+
+__BEGIN_DECLS
+
+/*
+ * Wide-character classification functions: 7.15.2.1.
+ */
+
+/* Test for any wide character for which `iswalpha' or `iswdigit' is
+   true.  */
+extern int iswalnum (wint_t __wc) __THROW;
+
+/* Test for any wide character for which `iswupper' or 'iswlower' is
+   true, or any wide character that is one of a locale-specific set of
+   wide-characters for which none of `iswcntrl', `iswdigit',
+   `iswpunct', or `iswspace' is true.  */
+extern int iswalpha (wint_t __wc) __THROW;
+
+/* Test for any control wide character.  */
+extern int iswcntrl (wint_t __wc) __THROW;
+
+/* Test for any wide character that corresponds to a decimal-digit
+   character.  */
+extern int iswdigit (wint_t __wc) __THROW;
+
+/* Test for any wide character for which `iswprint' is true and
+   `iswspace' is false.  */
+extern int iswgraph (wint_t __wc) __THROW;
+
+/* Test for any wide character that corresponds to a lowercase letter
+   or is one of a locale-specific set of wide characters for which
+   none of `iswcntrl', `iswdigit', `iswpunct', or `iswspace' is true.  */
+extern int iswlower (wint_t __wc) __THROW;
+
+/* Test for any printing wide character.  */
+extern int iswprint (wint_t __wc) __THROW;
+
+/* Test for any printing wide character that is one of a
+   locale-specific et of wide characters for which neither `iswspace'
+   nor `iswalnum' is true.  */
+extern int iswpunct (wint_t __wc) __THROW;
+
+/* Test for any wide character that corresponds to a locale-specific
+   set of wide characters for which none of `iswalnum', `iswgraph', or
+   `iswpunct' is true.  */
+extern int iswspace (wint_t __wc) __THROW;
+
+/* Test for any wide character that corresponds to an uppercase letter
+   or is one of a locale-specific set of wide character for which none
+   of `iswcntrl', `iswdigit', `iswpunct', or `iswspace' is true.  */
+extern int iswupper (wint_t __wc) __THROW;
+
+/* Test for any wide character that corresponds to a hexadecimal-digit
+   character equivalent to that performed be the functions described
+   in the previous subclause.  */
+extern int iswxdigit (wint_t __wc) __THROW;
+
+/* Test for any wide character that corresponds to a standard blank
+   wide character or a locale-specific set of wide characters for
+   which `iswalnum' is false.  */
+# ifdef __USE_ISOC99
+extern int iswblank (wint_t __wc) __THROW;
+# endif
+
+/*
+ * Extensible wide-character classification functions: 7.15.2.2.
+ */
+
+/* Construct value that describes a class of wide characters identified
+   by the string argument PROPERTY.  */
+extern wctype_t wctype (const char *__property) __THROW;
+
+/* Determine whether the wide-character WC has the property described by
+   DESC.  */
+extern int iswctype (wint_t __wc, wctype_t __desc) __THROW;
+
+/*
+ * Wide-character case-mapping functions: 7.15.3.1.
+ */
+
+/* Converts an uppercase letter to the corresponding lowercase letter.  */
+extern wint_t towlower (wint_t __wc) __THROW;
+
+/* Converts an lowercase letter to the corresponding uppercase letter.  */
+extern wint_t towupper (wint_t __wc) __THROW;
+
+__END_DECLS
+
+#endif /* bits/wctype-wchar.h.  */
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@wordsize.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@wordsize.h
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@@ -0,0 +1,17 @@
+/* Determine the wordsize from the preprocessor defines.  */
+
+#if defined __x86_64__ && !defined __ILP32__
+# define __WORDSIZE	64
+#else
+# define __WORDSIZE	32
+#define __WORDSIZE32_SIZE_ULONG		0
+#define __WORDSIZE32_PTRDIFF_LONG	0
+#endif
+
+#ifdef __x86_64__
+# define __WORDSIZE_TIME64_COMPAT32	1
+/* Both x86-64 and x32 use the 64-bit system call interface.  */
+# define __SYSCALL_WORDSIZE		64
+#else
+# define __WORDSIZE_TIME64_COMPAT32	0
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@wordsize.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@wordsize.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@xopen_lim.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@xopen_lim.h
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index 0000000000000000000000000000000000000000..8e002d6e60ac4c4e008ace5dc6ddf2afb3231053
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@bits@xopen_lim.h
@@ -0,0 +1,148 @@
+/* Copyright (C) 1996-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+/*
+ * Never include this file directly; use <limits.h> instead.
+ */
+
+/* Additional definitions from X/Open Portability Guide, Issue 4, Version 2
+   System Interfaces and Headers, 4.16 <limits.h>
+
+   Please note only the values which are not greater than the minimum
+   stated in the standard document are listed.  The `sysconf' functions
+   should be used to obtain the actual value.  */
+
+#ifndef _XOPEN_LIM_H
+#define _XOPEN_LIM_H	1
+
+/* We do not provide fixed values for
+
+   ARG_MAX	Maximum length of argument to the `exec' function
+		including environment data.
+
+   ATEXIT_MAX	Maximum number of functions that may be registered
+		with `atexit'.
+
+   CHILD_MAX	Maximum number of simultaneous processes per real
+		user ID.
+
+   OPEN_MAX	Maximum number of files that one process can have open
+		at anyone time.
+
+   PAGESIZE
+   PAGE_SIZE	Size of bytes of a page.
+
+   PASS_MAX	Maximum number of significant bytes in a password.
+
+   We only provide a fixed limit for
+
+   IOV_MAX	Maximum number of `iovec' structures that one process has
+		available for use with `readv' or writev'.
+
+   if this is indeed fixed by the underlying system.
+*/
+
+
+/* Maximum number of `iovec' structures that may be used in a single call
+   to `readv', `writev', etc.  */
+#define	_XOPEN_IOV_MAX	_POSIX_UIO_MAXIOV
+
+#include <bits/uio_lim.h>
+#ifdef __IOV_MAX
+# define IOV_MAX __IOV_MAX
+#else
+# undef IOV_MAX
+#endif
+
+/* Maximum value of `digit' in calls to the `printf' and `scanf'
+   functions.  We have no limit, so return a reasonable value.  */
+#define NL_ARGMAX	_POSIX_ARG_MAX
+
+/* Maximum number of bytes in a `LANG' name.  We have no limit.  */
+#define NL_LANGMAX	_POSIX2_LINE_MAX
+
+/* Maximum message number.  We have no limit.  */
+#define NL_MSGMAX	INT_MAX
+
+/* Maximum number of bytes in N-to-1 collation mapping.  We have no
+   limit.  */
+#if defined __USE_GNU || !defined __USE_XOPEN2K8
+# define NL_NMAX	INT_MAX
+#endif
+
+/* Maximum set number.  We have no limit.  */
+#define NL_SETMAX	INT_MAX
+
+/* Maximum number of bytes in a message.  We have no limit.  */
+#define NL_TEXTMAX	INT_MAX
+
+/* Default process priority.  */
+#define NZERO		20
+
+
+/* Number of bits in a word of type `int'.  */
+#ifdef INT_MAX
+# if INT_MAX == 32767
+#  define WORD_BIT	16
+# else
+#  if INT_MAX == 2147483647
+#   define WORD_BIT	32
+#  else
+/* Safe assumption.  */
+#   define WORD_BIT	64
+#  endif
+# endif
+#elif defined __INT_MAX__
+# if __INT_MAX__ == 32767
+#  define WORD_BIT	16
+# else
+#  if __INT_MAX__ == 2147483647
+#   define WORD_BIT	32
+#  else
+/* Safe assumption.  */
+#   define WORD_BIT	64
+#  endif
+# endif
+#else
+# define WORD_BIT	32
+#endif
+
+/* Number of bits in a word of type `long int'.  */
+#ifdef LONG_MAX
+# if LONG_MAX == 2147483647
+#  define LONG_BIT	32
+# else
+/* Safe assumption.  */
+#  define LONG_BIT	64
+# endif
+#elif defined __LONG_MAX__
+# if __LONG_MAX__ == 2147483647
+#  define LONG_BIT	32
+# else
+/* Safe assumption.  */
+#  define LONG_BIT	64
+# endif
+#else
+# include <bits/wordsize.h>
+# if __WORDSIZE == 64
+#  define LONG_BIT	64
+# else
+#  define LONG_BIT	32
+# endif
+#endif
+
+#endif /* bits/xopen_lim.h */
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@ctype.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@ctype.h
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@@ -0,0 +1,329 @@
+/* Copyright (C) 1991-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+/*
+ *	ISO C99 Standard 7.4: Character handling	<ctype.h>
+ */
+
+#ifndef	_CTYPE_H
+#define	_CTYPE_H	1
+
+#include <features.h>
+#include <bits/types.h>
+
+__BEGIN_DECLS
+
+#ifndef _ISbit
+/* These are all the characteristics of characters.
+   If there get to be more than 16 distinct characteristics,
+   many things must be changed that use `unsigned short int's.
+
+   The characteristics are stored always in network byte order (big
+   endian).  We define the bit value interpretations here dependent on the
+   machine's byte order.  */
+
+# include <bits/endian.h>
+# if __BYTE_ORDER == __BIG_ENDIAN
+#  define _ISbit(bit)	(1 << (bit))
+# else /* __BYTE_ORDER == __LITTLE_ENDIAN */
+#  define _ISbit(bit)	((bit) < 8 ? ((1 << (bit)) << 8) : ((1 << (bit)) >> 8))
+# endif
+
+enum
+{
+  _ISupper = _ISbit (0),	/* UPPERCASE.  */
+  _ISlower = _ISbit (1),	/* lowercase.  */
+  _ISalpha = _ISbit (2),	/* Alphabetic.  */
+  _ISdigit = _ISbit (3),	/* Numeric.  */
+  _ISxdigit = _ISbit (4),	/* Hexadecimal numeric.  */
+  _ISspace = _ISbit (5),	/* Whitespace.  */
+  _ISprint = _ISbit (6),	/* Printing.  */
+  _ISgraph = _ISbit (7),	/* Graphical.  */
+  _ISblank = _ISbit (8),	/* Blank (usually SPC and TAB).  */
+  _IScntrl = _ISbit (9),	/* Control character.  */
+  _ISpunct = _ISbit (10),	/* Punctuation.  */
+  _ISalnum = _ISbit (11)	/* Alphanumeric.  */
+};
+#endif /* ! _ISbit  */
+
+/* These are defined in ctype-info.c.
+   The declarations here must match those in localeinfo.h.
+
+   In the thread-specific locale model (see `uselocale' in <locale.h>)
+   we cannot use global variables for these as was done in the past.
+   Instead, the following accessor functions return the address of
+   each variable, which is local to the current thread if multithreaded.
+
+   These point into arrays of 384, so they can be indexed by any `unsigned
+   char' value [0,255]; by EOF (-1); or by any `signed char' value
+   [-128,-1).  ISO C requires that the ctype functions work for `unsigned
+   char' values and for EOF; we also support negative `signed char' values
+   for broken old programs.  The case conversion arrays are of `int's
+   rather than `unsigned char's because tolower (EOF) must be EOF, which
+   doesn't fit into an `unsigned char'.  But today more important is that
+   the arrays are also used for multi-byte character sets.  */
+extern const unsigned short int **__ctype_b_loc (void)
+     __THROW __attribute__ ((__const__));
+extern const __int32_t **__ctype_tolower_loc (void)
+     __THROW __attribute__ ((__const__));
+extern const __int32_t **__ctype_toupper_loc (void)
+     __THROW __attribute__ ((__const__));
+
+
+#ifndef __cplusplus
+# define __isctype(c, type) \
+  ((*__ctype_b_loc ())[(int) (c)] & (unsigned short int) type)
+#elif defined __USE_EXTERN_INLINES
+# define __isctype_f(type) \
+  __extern_inline int							      \
+  is##type (int __c) __THROW						      \
+  {									      \
+    return (*__ctype_b_loc ())[(int) (__c)] & (unsigned short int) _IS##type; \
+  }
+#endif
+
+#define	__isascii(c)	(((c) & ~0x7f) == 0)	/* If C is a 7 bit value.  */
+#define	__toascii(c)	((c) & 0x7f)		/* Mask off high bits.  */
+
+#define	__exctype(name)	extern int name (int) __THROW
+
+/* The following names are all functions:
+     int isCHARACTERISTIC(int c);
+   which return nonzero iff C has CHARACTERISTIC.
+   For the meaning of the characteristic names, see the `enum' above.  */
+__exctype (isalnum);
+__exctype (isalpha);
+__exctype (iscntrl);
+__exctype (isdigit);
+__exctype (islower);
+__exctype (isgraph);
+__exctype (isprint);
+__exctype (ispunct);
+__exctype (isspace);
+__exctype (isupper);
+__exctype (isxdigit);
+
+
+/* Return the lowercase version of C.  */
+extern int tolower (int __c) __THROW;
+
+/* Return the uppercase version of C.  */
+extern int toupper (int __c) __THROW;
+
+
+/* ISO C99 introduced one new function.  */
+#ifdef	__USE_ISOC99
+__exctype (isblank);
+#endif
+
+#ifdef __USE_GNU
+/* Test C for a set of character classes according to MASK.  */
+extern int isctype (int __c, int __mask) __THROW;
+#endif
+
+#if defined __USE_MISC || defined __USE_XOPEN
+
+/* Return nonzero iff C is in the ASCII set
+   (i.e., is no more than 7 bits wide).  */
+extern int isascii (int __c) __THROW;
+
+/* Return the part of C that is in the ASCII set
+   (i.e., the low-order 7 bits of C).  */
+extern int toascii (int __c) __THROW;
+
+/* These are the same as `toupper' and `tolower' except that they do not
+   check the argument for being in the range of a `char'.  */
+__exctype (_toupper);
+__exctype (_tolower);
+#endif /* Use X/Open or use misc.  */
+
+/* This code is needed for the optimized mapping functions.  */
+#define __tobody(c, f, a, args) \
+  (__extension__							      \
+   ({ int __res;							      \
+      if (sizeof (c) > 1)						      \
+	{								      \
+	  if (__builtin_constant_p (c))					      \
+	    {								      \
+	      int __c = (c);						      \
+	      __res = __c < -128 || __c > 255 ? __c : (a)[__c];		      \
+	    }								      \
+	  else								      \
+	    __res = f args;						      \
+	}								      \
+      else								      \
+	__res = (a)[(int) (c)];						      \
+      __res; }))
+
+#if !defined __NO_CTYPE
+# ifdef __isctype_f
+__isctype_f (alnum)
+__isctype_f (alpha)
+__isctype_f (cntrl)
+__isctype_f (digit)
+__isctype_f (lower)
+__isctype_f (graph)
+__isctype_f (print)
+__isctype_f (punct)
+__isctype_f (space)
+__isctype_f (upper)
+__isctype_f (xdigit)
+#  ifdef __USE_ISOC99
+__isctype_f (blank)
+#  endif
+# elif defined __isctype
+# define isalnum(c)	__isctype((c), _ISalnum)
+# define isalpha(c)	__isctype((c), _ISalpha)
+# define iscntrl(c)	__isctype((c), _IScntrl)
+# define isdigit(c)	__isctype((c), _ISdigit)
+# define islower(c)	__isctype((c), _ISlower)
+# define isgraph(c)	__isctype((c), _ISgraph)
+# define isprint(c)	__isctype((c), _ISprint)
+# define ispunct(c)	__isctype((c), _ISpunct)
+# define isspace(c)	__isctype((c), _ISspace)
+# define isupper(c)	__isctype((c), _ISupper)
+# define isxdigit(c)	__isctype((c), _ISxdigit)
+#  ifdef __USE_ISOC99
+#   define isblank(c)	__isctype((c), _ISblank)
+#  endif
+# endif
+
+# ifdef __USE_EXTERN_INLINES
+__extern_inline int
+__NTH (tolower (int __c))
+{
+  return __c >= -128 && __c < 256 ? (*__ctype_tolower_loc ())[__c] : __c;
+}
+
+__extern_inline int
+__NTH (toupper (int __c))
+{
+  return __c >= -128 && __c < 256 ? (*__ctype_toupper_loc ())[__c] : __c;
+}
+# endif
+
+# if __GNUC__ >= 2 && defined __OPTIMIZE__ && !defined __cplusplus
+#  define tolower(c)	__tobody (c, tolower, *__ctype_tolower_loc (), (c))
+#  define toupper(c)	__tobody (c, toupper, *__ctype_toupper_loc (), (c))
+# endif /* Optimizing gcc */
+
+# if defined __USE_MISC || defined __USE_XOPEN
+#  define isascii(c)	__isascii (c)
+#  define toascii(c)	__toascii (c)
+
+#  define _tolower(c)	((int) (*__ctype_tolower_loc ())[(int) (c)])
+#  define _toupper(c)	((int) (*__ctype_toupper_loc ())[(int) (c)])
+# endif
+
+#endif /* Not __NO_CTYPE.  */
+
+
+#ifdef __USE_XOPEN2K8
+/* POSIX.1-2008 extended locale interface (see locale.h).  */
+# include <bits/types/locale_t.h>
+
+/* These definitions are similar to the ones above but all functions
+   take as an argument a handle for the locale which shall be used.  */
+#  define __isctype_l(c, type, locale) \
+  ((locale)->__ctype_b[(int) (c)] & (unsigned short int) type)
+
+# define __exctype_l(name) 						      \
+  extern int name (int, locale_t) __THROW
+
+/* The following names are all functions:
+     int isCHARACTERISTIC(int c, locale_t *locale);
+   which return nonzero iff C has CHARACTERISTIC.
+   For the meaning of the characteristic names, see the `enum' above.  */
+__exctype_l (isalnum_l);
+__exctype_l (isalpha_l);
+__exctype_l (iscntrl_l);
+__exctype_l (isdigit_l);
+__exctype_l (islower_l);
+__exctype_l (isgraph_l);
+__exctype_l (isprint_l);
+__exctype_l (ispunct_l);
+__exctype_l (isspace_l);
+__exctype_l (isupper_l);
+__exctype_l (isxdigit_l);
+
+__exctype_l (isblank_l);
+
+
+/* Return the lowercase version of C in locale L.  */
+extern int __tolower_l (int __c, locale_t __l) __THROW;
+extern int tolower_l (int __c, locale_t __l) __THROW;
+
+/* Return the uppercase version of C.  */
+extern int __toupper_l (int __c, locale_t __l) __THROW;
+extern int toupper_l (int __c, locale_t __l) __THROW;
+
+# if __GNUC__ >= 2 && defined __OPTIMIZE__ && !defined __cplusplus
+#  define __tolower_l(c, locale) \
+  __tobody (c, __tolower_l, (locale)->__ctype_tolower, (c, locale))
+#  define __toupper_l(c, locale) \
+  __tobody (c, __toupper_l, (locale)->__ctype_toupper, (c, locale))
+#  define tolower_l(c, locale)	__tolower_l ((c), (locale))
+#  define toupper_l(c, locale)	__toupper_l ((c), (locale))
+# endif	/* Optimizing gcc */
+
+
+# ifndef __NO_CTYPE
+#  define __isalnum_l(c,l)	__isctype_l((c), _ISalnum, (l))
+#  define __isalpha_l(c,l)	__isctype_l((c), _ISalpha, (l))
+#  define __iscntrl_l(c,l)	__isctype_l((c), _IScntrl, (l))
+#  define __isdigit_l(c,l)	__isctype_l((c), _ISdigit, (l))
+#  define __islower_l(c,l)	__isctype_l((c), _ISlower, (l))
+#  define __isgraph_l(c,l)	__isctype_l((c), _ISgraph, (l))
+#  define __isprint_l(c,l)	__isctype_l((c), _ISprint, (l))
+#  define __ispunct_l(c,l)	__isctype_l((c), _ISpunct, (l))
+#  define __isspace_l(c,l)	__isctype_l((c), _ISspace, (l))
+#  define __isupper_l(c,l)	__isctype_l((c), _ISupper, (l))
+#  define __isxdigit_l(c,l)	__isctype_l((c), _ISxdigit, (l))
+
+#  define __isblank_l(c,l)	__isctype_l((c), _ISblank, (l))
+
+#  ifdef __USE_MISC
+#   define __isascii_l(c,l)	((l), __isascii (c))
+#   define __toascii_l(c,l)	((l), __toascii (c))
+#  endif
+
+#  define isalnum_l(c,l)	__isalnum_l ((c), (l))
+#  define isalpha_l(c,l)	__isalpha_l ((c), (l))
+#  define iscntrl_l(c,l)	__iscntrl_l ((c), (l))
+#  define isdigit_l(c,l)	__isdigit_l ((c), (l))
+#  define islower_l(c,l)	__islower_l ((c), (l))
+#  define isgraph_l(c,l)	__isgraph_l ((c), (l))
+#  define isprint_l(c,l)	__isprint_l ((c), (l))
+#  define ispunct_l(c,l)	__ispunct_l ((c), (l))
+#  define isspace_l(c,l)	__isspace_l ((c), (l))
+#  define isupper_l(c,l)	__isupper_l ((c), (l))
+#  define isxdigit_l(c,l)	__isxdigit_l ((c), (l))
+
+#  define isblank_l(c,l)	__isblank_l ((c), (l))
+
+#  ifdef __USE_MISC
+#   define isascii_l(c,l)	__isascii_l ((c), (l))
+#   define toascii_l(c,l)	__toascii_l ((c), (l))
+#  endif
+
+# endif /* Not __NO_CTYPE.  */
+
+#endif /* Use POSIX 2008.  */
+
+__END_DECLS
+
+#endif /* ctype.h  */
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@endian.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@endian.h
new file mode 100644
index 0000000000000000000000000000000000000000..f91984686103d71b5bf499077d8eac4a0e0184c6
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@endian.h
@@ -0,0 +1,72 @@
+/* Copyright (C) 1992-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef	_ENDIAN_H
+#define	_ENDIAN_H	1
+
+#include <features.h>
+
+/* Get the definitions of __*_ENDIAN, __BYTE_ORDER, and __FLOAT_WORD_ORDER.  */
+#include <bits/endian.h>
+
+#ifdef __USE_MISC
+# define LITTLE_ENDIAN	__LITTLE_ENDIAN
+# define BIG_ENDIAN	__BIG_ENDIAN
+# define PDP_ENDIAN	__PDP_ENDIAN
+# define BYTE_ORDER	__BYTE_ORDER
+#endif
+
+#if defined __USE_MISC && !defined __ASSEMBLER__
+/* Conversion interfaces.  */
+# include <bits/byteswap.h>
+# include <bits/uintn-identity.h>
+
+# if __BYTE_ORDER == __LITTLE_ENDIAN
+#  define htobe16(x) __bswap_16 (x)
+#  define htole16(x) __uint16_identity (x)
+#  define be16toh(x) __bswap_16 (x)
+#  define le16toh(x) __uint16_identity (x)
+
+#  define htobe32(x) __bswap_32 (x)
+#  define htole32(x) __uint32_identity (x)
+#  define be32toh(x) __bswap_32 (x)
+#  define le32toh(x) __uint32_identity (x)
+
+#  define htobe64(x) __bswap_64 (x)
+#  define htole64(x) __uint64_identity (x)
+#  define be64toh(x) __bswap_64 (x)
+#  define le64toh(x) __uint64_identity (x)
+
+# else
+#  define htobe16(x) __uint16_identity (x)
+#  define htole16(x) __bswap_16 (x)
+#  define be16toh(x) __uint16_identity (x)
+#  define le16toh(x) __bswap_16 (x)
+
+#  define htobe32(x) __uint32_identity (x)
+#  define htole32(x) __bswap_32 (x)
+#  define be32toh(x) __uint32_identity (x)
+#  define le32toh(x) __bswap_32 (x)
+
+#  define htobe64(x) __uint64_identity (x)
+#  define htole64(x) __bswap_64 (x)
+#  define be64toh(x) __uint64_identity (x)
+#  define le64toh(x) __bswap_64 (x)
+# endif
+#endif
+
+#endif	/* endian.h */
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@errno.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@errno.h
new file mode 100644
index 0000000000000000000000000000000000000000..c63d16e62b60a5030a4d2953771ec131b69889ca
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@errno.h
@@ -0,0 +1,55 @@
+/* Copyright (C) 1991-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+/*
+ *	ISO C99 Standard: 7.5 Errors	<errno.h>
+ */
+
+#ifndef	_ERRNO_H
+#define	_ERRNO_H 1
+
+#include <features.h>
+
+/* The system-specific definitions of the E* constants, as macros.  */
+#include <bits/errno.h>
+
+/* When included from assembly language, this header only provides the
+   E* constants.  */
+#ifndef __ASSEMBLER__
+
+__BEGIN_DECLS
+
+/* The error code set by various library functions.  */
+extern int *__errno_location (void) __THROW __attribute_const__;
+# define errno (*__errno_location ())
+
+# ifdef __USE_GNU
+
+/* The full and simple forms of the name with which the program was
+   invoked.  These variables are set up automatically at startup based on
+   the value of argv[0].  */
+extern char *program_invocation_name;
+extern char *program_invocation_short_name;
+
+#include <bits/types/error_t.h>
+
+# endif /* __USE_GNU */
+
+__END_DECLS
+
+#endif /* !__ASSEMBLER__ */
+#endif /* errno.h */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@errno.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@errno.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@features-time64.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@features-time64.h
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index 0000000000000000000000000000000000000000..84d56ee3ff2ecfa0d2499385623f30606f84a1bf
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@features-time64.h
@@ -0,0 +1,37 @@
+/* Features part to handle 64-bit time_t support.
+   Copyright (C) 2021-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+/* We need to know the word size in order to check the time size.  */
+#include <bits/wordsize.h>
+#include <bits/timesize.h>
+
+#if defined _TIME_BITS
+# if _TIME_BITS == 64
+#  if ! defined (_FILE_OFFSET_BITS) || _FILE_OFFSET_BITS != 64
+#   error "_TIME_BITS=64 is allowed only with _FILE_OFFSET_BITS=64"
+#  elif __TIMESIZE == 32
+#   define __USE_TIME_BITS64	1
+#  endif
+# elif _TIME_BITS == 32
+#  if __TIMESIZE > 32
+#   error "_TIME_BITS=32 is not compatible with __TIMESIZE > 32"
+#  endif
+# else
+#  error Invalid _TIME_BITS value (can only be 32 or 64-bit)
+# endif
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@features-time64.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@features-time64.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@features.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@features.h
new file mode 100644
index 0000000000000000000000000000000000000000..76b8b973d48317aee66929744107ecb9c4d2f776
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@features.h
@@ -0,0 +1,517 @@
+/* Copyright (C) 1991-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef	_FEATURES_H
+#define	_FEATURES_H	1
+
+/* These are defined by the user (or the compiler)
+   to specify the desired environment:
+
+   __STRICT_ANSI__	ISO Standard C.
+   _ISOC99_SOURCE	Extensions to ISO C89 from ISO C99.
+   _ISOC11_SOURCE	Extensions to ISO C99 from ISO C11.
+   _ISOC2X_SOURCE	Extensions to ISO C99 from ISO C2X.
+   __STDC_WANT_LIB_EXT2__
+			Extensions to ISO C99 from TR 27431-2:2010.
+   __STDC_WANT_IEC_60559_BFP_EXT__
+			Extensions to ISO C11 from TS 18661-1:2014.
+   __STDC_WANT_IEC_60559_FUNCS_EXT__
+			Extensions to ISO C11 from TS 18661-4:2015.
+   __STDC_WANT_IEC_60559_TYPES_EXT__
+			Extensions to ISO C11 from TS 18661-3:2015.
+   __STDC_WANT_IEC_60559_EXT__
+			ISO C2X interfaces defined only in Annex F.
+
+   _POSIX_SOURCE	IEEE Std 1003.1.
+   _POSIX_C_SOURCE	If ==1, like _POSIX_SOURCE; if >=2 add IEEE Std 1003.2;
+			if >=199309L, add IEEE Std 1003.1b-1993;
+			if >=199506L, add IEEE Std 1003.1c-1995;
+			if >=200112L, all of IEEE 1003.1-2004
+			if >=200809L, all of IEEE 1003.1-2008
+   _XOPEN_SOURCE	Includes POSIX and XPG things.  Set to 500 if
+			Single Unix conformance is wanted, to 600 for the
+			sixth revision, to 700 for the seventh revision.
+   _XOPEN_SOURCE_EXTENDED XPG things and X/Open Unix extensions.
+   _LARGEFILE_SOURCE	Some more functions for correct standard I/O.
+   _LARGEFILE64_SOURCE	Additional functionality from LFS for large files.
+   _FILE_OFFSET_BITS=N	Select default filesystem interface.
+   _ATFILE_SOURCE	Additional *at interfaces.
+   _DYNAMIC_STACK_SIZE_SOURCE Select correct (but non compile-time constant)
+			MINSIGSTKSZ, SIGSTKSZ and PTHREAD_STACK_MIN.
+   _GNU_SOURCE		All of the above, plus GNU extensions.
+   _DEFAULT_SOURCE	The default set of features (taking precedence over
+			__STRICT_ANSI__).
+
+   _FORTIFY_SOURCE	Add security hardening to many library functions.
+			Set to 1 or 2; 2 performs stricter checks than 1.
+
+   _REENTRANT, _THREAD_SAFE
+			Obsolete; equivalent to _POSIX_C_SOURCE=199506L.
+
+   The `-ansi' switch to the GNU C compiler, and standards conformance
+   options such as `-std=c99', define __STRICT_ANSI__.  If none of
+   these are defined, or if _DEFAULT_SOURCE is defined, the default is
+   to have _POSIX_SOURCE set to one and _POSIX_C_SOURCE set to
+   200809L, as well as enabling miscellaneous functions from BSD and
+   SVID.  If more than one of these are defined, they accumulate.  For
+   example __STRICT_ANSI__, _POSIX_SOURCE and _POSIX_C_SOURCE together
+   give you ISO C, 1003.1, and 1003.2, but nothing else.
+
+   These are defined by this file and are used by the
+   header files to decide what to declare or define:
+
+   __GLIBC_USE (F)	Define things from feature set F.  This is defined
+			to 1 or 0; the subsequent macros are either defined
+			or undefined, and those tests should be moved to
+			__GLIBC_USE.
+   __USE_ISOC11		Define ISO C11 things.
+   __USE_ISOC99		Define ISO C99 things.
+   __USE_ISOC95		Define ISO C90 AMD1 (C95) things.
+   __USE_ISOCXX11	Define ISO C++11 things.
+   __USE_POSIX		Define IEEE Std 1003.1 things.
+   __USE_POSIX2		Define IEEE Std 1003.2 things.
+   __USE_POSIX199309	Define IEEE Std 1003.1, and .1b things.
+   __USE_POSIX199506	Define IEEE Std 1003.1, .1b, .1c and .1i things.
+   __USE_XOPEN		Define XPG things.
+   __USE_XOPEN_EXTENDED	Define X/Open Unix things.
+   __USE_UNIX98		Define Single Unix V2 things.
+   __USE_XOPEN2K        Define XPG6 things.
+   __USE_XOPEN2KXSI     Define XPG6 XSI things.
+   __USE_XOPEN2K8       Define XPG7 things.
+   __USE_XOPEN2K8XSI    Define XPG7 XSI things.
+   __USE_LARGEFILE	Define correct standard I/O things.
+   __USE_LARGEFILE64	Define LFS things with separate names.
+   __USE_FILE_OFFSET64	Define 64bit interface as default.
+   __USE_MISC		Define things from 4.3BSD or System V Unix.
+   __USE_ATFILE		Define *at interfaces and AT_* constants for them.
+   __USE_DYNAMIC_STACK_SIZE Define correct (but non compile-time constant)
+			MINSIGSTKSZ, SIGSTKSZ and PTHREAD_STACK_MIN.
+   __USE_GNU		Define GNU extensions.
+   __USE_FORTIFY_LEVEL	Additional security measures used, according to level.
+
+   The macros `__GNU_LIBRARY__', `__GLIBC__', and `__GLIBC_MINOR__' are
+   defined by this file unconditionally.  `__GNU_LIBRARY__' is provided
+   only for compatibility.  All new code should use the other symbols
+   to test for features.
+
+   All macros listed above as possibly being defined by this file are
+   explicitly undefined if they are not explicitly defined.
+   Feature-test macros that are not defined by the user or compiler
+   but are implied by the other feature-test macros defined (or by the
+   lack of any definitions) are defined by the file.
+
+   ISO C feature test macros depend on the definition of the macro
+   when an affected header is included, not when the first system
+   header is included, and so they are handled in
+   <bits/libc-header-start.h>, which does not have a multiple include
+   guard.  Feature test macros that can be handled from the first
+   system header included are handled here.  */
+
+
+/* Undefine everything, so we get a clean slate.  */
+#undef	__USE_ISOC11
+#undef	__USE_ISOC99
+#undef	__USE_ISOC95
+#undef	__USE_ISOCXX11
+#undef	__USE_POSIX
+#undef	__USE_POSIX2
+#undef	__USE_POSIX199309
+#undef	__USE_POSIX199506
+#undef	__USE_XOPEN
+#undef	__USE_XOPEN_EXTENDED
+#undef	__USE_UNIX98
+#undef	__USE_XOPEN2K
+#undef	__USE_XOPEN2KXSI
+#undef	__USE_XOPEN2K8
+#undef	__USE_XOPEN2K8XSI
+#undef	__USE_LARGEFILE
+#undef	__USE_LARGEFILE64
+#undef	__USE_FILE_OFFSET64
+#undef	__USE_MISC
+#undef	__USE_ATFILE
+#undef	__USE_DYNAMIC_STACK_SIZE
+#undef	__USE_GNU
+#undef	__USE_FORTIFY_LEVEL
+#undef	__KERNEL_STRICT_NAMES
+#undef	__GLIBC_USE_ISOC2X
+#undef	__GLIBC_USE_DEPRECATED_GETS
+#undef	__GLIBC_USE_DEPRECATED_SCANF
+
+/* Suppress kernel-name space pollution unless user expressedly asks
+   for it.  */
+#ifndef _LOOSE_KERNEL_NAMES
+# define __KERNEL_STRICT_NAMES
+#endif
+
+/* Convenience macro to test the version of gcc.
+   Use like this:
+   #if __GNUC_PREREQ (2,8)
+   ... code requiring gcc 2.8 or later ...
+   #endif
+   Note: only works for GCC 2.0 and later, because __GNUC_MINOR__ was
+   added in 2.0.  */
+#if defined __GNUC__ && defined __GNUC_MINOR__
+# define __GNUC_PREREQ(maj, min) \
+	((__GNUC__ << 16) + __GNUC_MINOR__ >= ((maj) << 16) + (min))
+#else
+# define __GNUC_PREREQ(maj, min) 0
+#endif
+
+/* Similarly for clang.  Features added to GCC after version 4.2 may
+   or may not also be available in clang, and clang's definitions of
+   __GNUC(_MINOR)__ are fixed at 4 and 2 respectively.  Not all such
+   features can be queried via __has_extension/__has_feature.  */
+#if defined __clang_major__ && defined __clang_minor__
+# define __glibc_clang_prereq(maj, min) \
+  ((__clang_major__ << 16) + __clang_minor__ >= ((maj) << 16) + (min))
+#else
+# define __glibc_clang_prereq(maj, min) 0
+#endif
+
+/* Whether to use feature set F.  */
+#define __GLIBC_USE(F)	__GLIBC_USE_ ## F
+
+/* _BSD_SOURCE and _SVID_SOURCE are deprecated aliases for
+   _DEFAULT_SOURCE.  If _DEFAULT_SOURCE is present we do not
+   issue a warning; the expectation is that the source is being
+   transitioned to use the new macro.  */
+#if (defined _BSD_SOURCE || defined _SVID_SOURCE) \
+    && !defined _DEFAULT_SOURCE
+# warning "_BSD_SOURCE and _SVID_SOURCE are deprecated, use _DEFAULT_SOURCE"
+# undef  _DEFAULT_SOURCE
+# define _DEFAULT_SOURCE	1
+#endif
+
+/* If _GNU_SOURCE was defined by the user, turn on all the other features.  */
+#ifdef _GNU_SOURCE
+# undef  _ISOC95_SOURCE
+# define _ISOC95_SOURCE	1
+# undef  _ISOC99_SOURCE
+# define _ISOC99_SOURCE	1
+# undef  _ISOC11_SOURCE
+# define _ISOC11_SOURCE	1
+# undef  _ISOC2X_SOURCE
+# define _ISOC2X_SOURCE	1
+# undef  _POSIX_SOURCE
+# define _POSIX_SOURCE	1
+# undef  _POSIX_C_SOURCE
+# define _POSIX_C_SOURCE	200809L
+# undef  _XOPEN_SOURCE
+# define _XOPEN_SOURCE	700
+# undef  _XOPEN_SOURCE_EXTENDED
+# define _XOPEN_SOURCE_EXTENDED	1
+# undef	 _LARGEFILE64_SOURCE
+# define _LARGEFILE64_SOURCE	1
+# undef  _DEFAULT_SOURCE
+# define _DEFAULT_SOURCE	1
+# undef  _ATFILE_SOURCE
+# define _ATFILE_SOURCE	1
+# undef  _DYNAMIC_STACK_SIZE_SOURCE
+# define _DYNAMIC_STACK_SIZE_SOURCE 1
+#endif
+
+/* If nothing (other than _GNU_SOURCE and _DEFAULT_SOURCE) is defined,
+   define _DEFAULT_SOURCE.  */
+#if (defined _DEFAULT_SOURCE					\
+     || (!defined __STRICT_ANSI__				\
+	 && !defined _ISOC99_SOURCE && !defined _ISOC11_SOURCE	\
+	 && !defined _ISOC2X_SOURCE				\
+	 && !defined _POSIX_SOURCE && !defined _POSIX_C_SOURCE	\
+	 && !defined _XOPEN_SOURCE))
+# undef  _DEFAULT_SOURCE
+# define _DEFAULT_SOURCE	1
+#endif
+
+/* This is to enable the ISO C2X extension.  */
+#if (defined _ISOC2X_SOURCE \
+     || (defined __STDC_VERSION__ && __STDC_VERSION__ > 201710L))
+# define __GLIBC_USE_ISOC2X	1
+#else
+# define __GLIBC_USE_ISOC2X	0
+#endif
+
+/* This is to enable the ISO C11 extension.  */
+#if (defined _ISOC11_SOURCE || defined _ISOC2X_SOURCE \
+     || (defined __STDC_VERSION__ && __STDC_VERSION__ >= 201112L))
+# define __USE_ISOC11	1
+#endif
+
+/* This is to enable the ISO C99 extension.  */
+#if (defined _ISOC99_SOURCE || defined _ISOC11_SOURCE			\
+     || defined _ISOC2X_SOURCE						\
+     || (defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L))
+# define __USE_ISOC99	1
+#endif
+
+/* This is to enable the ISO C90 Amendment 1:1995 extension.  */
+#if (defined _ISOC99_SOURCE || defined _ISOC11_SOURCE			\
+     || defined _ISOC2X_SOURCE						\
+     || (defined __STDC_VERSION__ && __STDC_VERSION__ >= 199409L))
+# define __USE_ISOC95	1
+#endif
+
+#ifdef __cplusplus
+/* This is to enable compatibility for ISO C++17.  */
+# if __cplusplus >= 201703L
+#  define __USE_ISOC11	1
+# endif
+/* This is to enable compatibility for ISO C++11.
+   Check the temporary macro for now, too.  */
+# if __cplusplus >= 201103L || defined __GXX_EXPERIMENTAL_CXX0X__
+#  define __USE_ISOCXX11	1
+#  define __USE_ISOC99	1
+# endif
+#endif
+
+/* If none of the ANSI/POSIX macros are defined, or if _DEFAULT_SOURCE
+   is defined, use POSIX.1-2008 (or another version depending on
+   _XOPEN_SOURCE).  */
+#ifdef _DEFAULT_SOURCE
+# if !defined _POSIX_SOURCE && !defined _POSIX_C_SOURCE
+#  define __USE_POSIX_IMPLICITLY	1
+# endif
+# undef  _POSIX_SOURCE
+# define _POSIX_SOURCE	1
+# undef  _POSIX_C_SOURCE
+# define _POSIX_C_SOURCE	200809L
+#endif
+
+#if ((!defined __STRICT_ANSI__					\
+      || (defined _XOPEN_SOURCE && (_XOPEN_SOURCE - 0) >= 500))	\
+     && !defined _POSIX_SOURCE && !defined _POSIX_C_SOURCE)
+# define _POSIX_SOURCE	1
+# if defined _XOPEN_SOURCE && (_XOPEN_SOURCE - 0) < 500
+#  define _POSIX_C_SOURCE	2
+# elif defined _XOPEN_SOURCE && (_XOPEN_SOURCE - 0) < 600
+#  define _POSIX_C_SOURCE	199506L
+# elif defined _XOPEN_SOURCE && (_XOPEN_SOURCE - 0) < 700
+#  define _POSIX_C_SOURCE	200112L
+# else
+#  define _POSIX_C_SOURCE	200809L
+# endif
+# define __USE_POSIX_IMPLICITLY	1
+#endif
+
+/* Some C libraries once required _REENTRANT and/or _THREAD_SAFE to be
+   defined in all multithreaded code.  GNU libc has not required this
+   for many years.  We now treat them as compatibility synonyms for
+   _POSIX_C_SOURCE=199506L, which is the earliest level of POSIX with
+   comprehensive support for multithreaded code.  Using them never
+   lowers the selected level of POSIX conformance, only raises it.  */
+#if ((!defined _POSIX_C_SOURCE || (_POSIX_C_SOURCE - 0) < 199506L) \
+     && (defined _REENTRANT || defined _THREAD_SAFE))
+# define _POSIX_SOURCE   1
+# undef  _POSIX_C_SOURCE
+# define _POSIX_C_SOURCE 199506L
+#endif
+
+#if (defined _POSIX_SOURCE					\
+     || (defined _POSIX_C_SOURCE && _POSIX_C_SOURCE >= 1)	\
+     || defined _XOPEN_SOURCE)
+# define __USE_POSIX	1
+#endif
+
+#if defined _POSIX_C_SOURCE && _POSIX_C_SOURCE >= 2 || defined _XOPEN_SOURCE
+# define __USE_POSIX2	1
+#endif
+
+#if defined _POSIX_C_SOURCE && (_POSIX_C_SOURCE - 0) >= 199309L
+# define __USE_POSIX199309	1
+#endif
+
+#if defined _POSIX_C_SOURCE && (_POSIX_C_SOURCE - 0) >= 199506L
+# define __USE_POSIX199506	1
+#endif
+
+#if defined _POSIX_C_SOURCE && (_POSIX_C_SOURCE - 0) >= 200112L
+# define __USE_XOPEN2K		1
+# undef __USE_ISOC95
+# define __USE_ISOC95		1
+# undef __USE_ISOC99
+# define __USE_ISOC99		1
+#endif
+
+#if defined _POSIX_C_SOURCE && (_POSIX_C_SOURCE - 0) >= 200809L
+# define __USE_XOPEN2K8		1
+# undef  _ATFILE_SOURCE
+# define _ATFILE_SOURCE	1
+#endif
+
+#ifdef	_XOPEN_SOURCE
+# define __USE_XOPEN	1
+# if (_XOPEN_SOURCE - 0) >= 500
+#  define __USE_XOPEN_EXTENDED	1
+#  define __USE_UNIX98	1
+#  undef _LARGEFILE_SOURCE
+#  define _LARGEFILE_SOURCE	1
+#  if (_XOPEN_SOURCE - 0) >= 600
+#   if (_XOPEN_SOURCE - 0) >= 700
+#    define __USE_XOPEN2K8	1
+#    define __USE_XOPEN2K8XSI	1
+#   endif
+#   define __USE_XOPEN2K	1
+#   define __USE_XOPEN2KXSI	1
+#   undef __USE_ISOC95
+#   define __USE_ISOC95		1
+#   undef __USE_ISOC99
+#   define __USE_ISOC99		1
+#  endif
+# else
+#  ifdef _XOPEN_SOURCE_EXTENDED
+#   define __USE_XOPEN_EXTENDED	1
+#  endif
+# endif
+#endif
+
+#ifdef _LARGEFILE_SOURCE
+# define __USE_LARGEFILE	1
+#endif
+
+#ifdef _LARGEFILE64_SOURCE
+# define __USE_LARGEFILE64	1
+#endif
+
+#if defined _FILE_OFFSET_BITS && _FILE_OFFSET_BITS == 64
+# define __USE_FILE_OFFSET64	1
+#endif
+
+#include <features-time64.h>
+
+#if defined _DEFAULT_SOURCE
+# define __USE_MISC	1
+#endif
+
+#ifdef	_ATFILE_SOURCE
+# define __USE_ATFILE	1
+#endif
+
+#ifdef	_DYNAMIC_STACK_SIZE_SOURCE
+# define __USE_DYNAMIC_STACK_SIZE	1
+#endif
+
+#ifdef	_GNU_SOURCE
+# define __USE_GNU	1
+#endif
+
+#if defined _FORTIFY_SOURCE && _FORTIFY_SOURCE > 0
+# if !defined __OPTIMIZE__ || __OPTIMIZE__ <= 0
+#  warning _FORTIFY_SOURCE requires compiling with optimization (-O)
+# elif !__GNUC_PREREQ (4, 1)
+#  warning _FORTIFY_SOURCE requires GCC 4.1 or later
+# elif _FORTIFY_SOURCE > 2 && (__glibc_clang_prereq (9, 0)		      \
+			       || __GNUC_PREREQ (12, 0))
+
+#  if _FORTIFY_SOURCE > 3
+#   warning _FORTIFY_SOURCE > 3 is treated like 3 on this platform
+#  endif
+#  define __USE_FORTIFY_LEVEL 3
+# elif _FORTIFY_SOURCE > 1
+#  if _FORTIFY_SOURCE > 2
+#   warning _FORTIFY_SOURCE > 2 is treated like 2 on this platform
+#  endif
+#  define __USE_FORTIFY_LEVEL 2
+# else
+#  define __USE_FORTIFY_LEVEL 1
+# endif
+#endif
+#ifndef __USE_FORTIFY_LEVEL
+# define __USE_FORTIFY_LEVEL 0
+#endif
+
+/* The function 'gets' existed in C89, but is impossible to use
+   safely.  It has been removed from ISO C11 and ISO C++14.  Note: for
+   compatibility with various implementations of <cstdio>, this test
+   must consider only the value of __cplusplus when compiling C++.  */
+#if defined __cplusplus ? __cplusplus >= 201402L : defined __USE_ISOC11
+# define __GLIBC_USE_DEPRECATED_GETS 0
+#else
+# define __GLIBC_USE_DEPRECATED_GETS 1
+#endif
+
+/* GNU formerly extended the scanf functions with modified format
+   specifiers %as, %aS, and %a[...] that allocate a buffer for the
+   input using malloc.  This extension conflicts with ISO C99, which
+   defines %a as a standalone format specifier that reads a floating-
+   point number; moreover, POSIX.1-2008 provides the same feature
+   using the modifier letter 'm' instead (%ms, %mS, %m[...]).
+
+   We now follow C99 unless GNU extensions are active and the compiler
+   is specifically in C89 or C++98 mode (strict or not).  For
+   instance, with GCC, -std=gnu11 will have C99-compliant scanf with
+   or without -D_GNU_SOURCE, but -std=c89 -D_GNU_SOURCE will have the
+   old extension.  */
+#if (defined __USE_GNU							\
+     && (defined __cplusplus						\
+	 ? (__cplusplus < 201103L && !defined __GXX_EXPERIMENTAL_CXX0X__) \
+	 : (!defined __STDC_VERSION__ || __STDC_VERSION__ < 199901L)))
+# define __GLIBC_USE_DEPRECATED_SCANF 1
+#else
+# define __GLIBC_USE_DEPRECATED_SCANF 0
+#endif
+
+/* Get definitions of __STDC_* predefined macros, if the compiler has
+   not preincluded this header automatically.  */
+#include <stdc-predef.h>
+
+/* This macro indicates that the installed library is the GNU C Library.
+   For historic reasons the value now is 6 and this will stay from now
+   on.  The use of this variable is deprecated.  Use __GLIBC__ and
+   __GLIBC_MINOR__ now (see below) when you want to test for a specific
+   GNU C library version and use the values in <gnu/lib-names.h> to get
+   the sonames of the shared libraries.  */
+#undef  __GNU_LIBRARY__
+#define __GNU_LIBRARY__ 6
+
+/* Major and minor version number of the GNU C library package.  Use
+   these macros to test for features in specific releases.  */
+#define	__GLIBC__	2
+#define	__GLIBC_MINOR__	35
+
+#define __GLIBC_PREREQ(maj, min) \
+	((__GLIBC__ << 16) + __GLIBC_MINOR__ >= ((maj) << 16) + (min))
+
+/* This is here only because every header file already includes this one.  */
+#ifndef __ASSEMBLER__
+# ifndef _SYS_CDEFS_H
+#  include <sys/cdefs.h>
+# endif
+
+/* If we don't have __REDIRECT, prototypes will be missing if
+   __USE_FILE_OFFSET64 but not __USE_LARGEFILE[64]. */
+# if defined __USE_FILE_OFFSET64 && !defined __REDIRECT
+#  define __USE_LARGEFILE	1
+#  define __USE_LARGEFILE64	1
+# endif
+
+#endif	/* !ASSEMBLER */
+
+/* Decide whether we can define 'extern inline' functions in headers.  */
+#if __GNUC_PREREQ (2, 7) && defined __OPTIMIZE__ \
+    && !defined __OPTIMIZE_SIZE__ && !defined __NO_INLINE__ \
+    && defined __extern_inline
+# define __USE_EXTERN_INLINES	1
+#endif
+
+
+/* This is here only because every header file already includes this one.
+   Get the definitions of all the appropriate `__stub_FUNCTION' symbols.
+   <gnu/stubs.h> contains `#define __stub_FUNCTION' when FUNCTION is a stub
+   that will always return failure (and set errno to ENOSYS).  */
+#include <gnu/stubs.h>
+
+
+#endif	/* features.h  */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@features.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@features.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@fenv.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@fenv.h
new file mode 100644
index 0000000000000000000000000000000000000000..992e9fbd416c70397f39adbd24e11b9e1edfe285
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@fenv.h
@@ -0,0 +1,170 @@
+/* Copyright (C) 1997-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+/*
+ * ISO C99 7.6: Floating-point environment	<fenv.h>
+ */
+
+#ifndef _FENV_H
+#define _FENV_H	1
+
+#define __GLIBC_INTERNAL_STARTING_HEADER_IMPLEMENTATION
+#include <bits/libc-header-start.h>
+
+/* Get the architecture dependend definitions.  The following definitions
+   are expected to be done:
+
+   fenv_t	type for object representing an entire floating-point
+		environment
+
+   FE_DFL_ENV	macro of type pointer to fenv_t to be used as the argument
+		to functions taking an argument of type fenv_t; in this
+		case the default environment will be used
+
+   fexcept_t	type for object representing the floating-point exception
+		flags including status associated with the flags
+
+   femode_t	type for object representing floating-point control modes
+
+   FE_DFL_MODE	macro of type pointer to const femode_t to be used as the
+		argument to fesetmode; in this case the default control
+		modes will be used
+
+   The following macros are defined iff the implementation supports this
+   kind of exception.
+   FE_INEXACT		inexact result
+   FE_DIVBYZERO		division by zero
+   FE_UNDERFLOW		result not representable due to underflow
+   FE_OVERFLOW		result not representable due to overflow
+   FE_INVALID		invalid operation
+
+   FE_ALL_EXCEPT	bitwise OR of all supported exceptions
+
+   The next macros are defined iff the appropriate rounding mode is
+   supported by the implementation.
+   FE_TONEAREST		round to nearest
+   FE_UPWARD		round toward +Inf
+   FE_DOWNWARD		round toward -Inf
+   FE_TOWARDZERO	round toward 0
+*/
+#include <bits/fenv.h>
+
+__BEGIN_DECLS
+
+/* Floating-point exception handling.  */
+
+/* Clear the supported exceptions represented by EXCEPTS.  */
+extern int feclearexcept (int __excepts) __THROW;
+
+/* Store implementation-defined representation of the exception flags
+   indicated by EXCEPTS in the object pointed to by FLAGP.  */
+extern int fegetexceptflag (fexcept_t *__flagp, int __excepts) __THROW;
+
+/* Raise the supported exceptions represented by EXCEPTS.  */
+extern int feraiseexcept (int __excepts) __THROW;
+
+#if __GLIBC_USE (IEC_60559_BFP_EXT_C2X)
+/* Set the supported exception flags represented by EXCEPTS, without
+   causing enabled traps to be taken.  */
+extern int fesetexcept (int __excepts) __THROW;
+#endif
+
+/* Set complete status for exceptions indicated by EXCEPTS according to
+   the representation in the object pointed to by FLAGP.  */
+extern int fesetexceptflag (const fexcept_t *__flagp, int __excepts) __THROW;
+
+/* Determine which of subset of the exceptions specified by EXCEPTS are
+   currently set.  */
+extern int fetestexcept (int __excepts) __THROW;
+
+#if __GLIBC_USE (IEC_60559_BFP_EXT_C2X)
+/* Determine which of subset of the exceptions specified by EXCEPTS
+   are set in *FLAGP.  */
+extern int fetestexceptflag (const fexcept_t *__flagp, int __excepts) __THROW;
+#endif
+
+
+/* Rounding control.  */
+
+/* Get current rounding direction.  */
+extern int fegetround (void) __THROW __attribute_pure__;
+
+/* Establish the rounding direction represented by ROUND.  */
+extern int fesetround (int __rounding_direction) __THROW;
+
+
+/* Floating-point environment.  */
+
+/* Store the current floating-point environment in the object pointed
+   to by ENVP.  */
+extern int fegetenv (fenv_t *__envp) __THROW;
+
+/* Save the current environment in the object pointed to by ENVP, clear
+   exception flags and install a non-stop mode (if available) for all
+   exceptions.  */
+extern int feholdexcept (fenv_t *__envp) __THROW;
+
+/* Establish the floating-point environment represented by the object
+   pointed to by ENVP.  */
+extern int fesetenv (const fenv_t *__envp) __THROW;
+
+/* Save current exceptions in temporary storage, install environment
+   represented by object pointed to by ENVP and raise exceptions
+   according to saved exceptions.  */
+extern int feupdateenv (const fenv_t *__envp) __THROW;
+
+
+/* Control modes.  */
+
+#if __GLIBC_USE (IEC_60559_BFP_EXT_C2X)
+/* Store the current floating-point control modes in the object
+   pointed to by MODEP.  */
+extern int fegetmode (femode_t *__modep) __THROW;
+
+/* Establish the floating-point control modes represented by the
+   object pointed to by MODEP.  */
+extern int fesetmode (const femode_t *__modep) __THROW;
+#endif
+
+
+/* NaN support.  */
+
+#if (__GLIBC_USE (IEC_60559_BFP_EXT_C2X)		\
+     && defined FE_INVALID			\
+     && defined __SUPPORT_SNAN__)
+# define FE_SNANS_ALWAYS_SIGNAL	1
+#endif
+
+#ifdef __USE_GNU
+
+/* Enable individual exceptions.  Will not enable more exceptions than
+   EXCEPTS specifies.  Returns the previous enabled exceptions if all
+   exceptions are successfully set, otherwise returns -1.  */
+extern int feenableexcept (int __excepts) __THROW;
+
+/* Disable individual exceptions.  Will not disable more exceptions than
+   EXCEPTS specifies.  Returns the previous enabled exceptions if all
+   exceptions are successfully disabled, otherwise returns -1.  */
+extern int fedisableexcept (int __excepts) __THROW;
+
+/* Return enabled exceptions.  */
+extern int fegetexcept (void) __THROW;
+#endif
+
+__END_DECLS
+
+#endif /* fenv.h */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@fenv.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@fenv.h.blob
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Binary files /dev/null and b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@fenv.h.blob differ
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@gnu@stubs-64.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@gnu@stubs-64.h
new file mode 100644
index 0000000000000000000000000000000000000000..b745721576c9fb62942410a17e2016cc10dc0884
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@gnu@stubs-64.h
@@ -0,0 +1,17 @@
+/* This file is automatically generated.
+   It defines a symbol `__stub_FUNCTION' for each function
+   in the C library which is a stub, meaning it will fail
+   every time called, usually setting errno to ENOSYS.  */
+
+#ifdef _LIBC
+ #error Applications may not define the macro _LIBC
+#endif
+
+#define __stub___compat_bdflush
+#define __stub_chflags
+#define __stub_fchflags
+#define __stub_gtty
+#define __stub_revoke
+#define __stub_setlogin
+#define __stub_sigreturn
+#define __stub_stty
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@gnu@stubs-64.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@gnu@stubs-64.h.blob
new file mode 100644
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Binary files /dev/null and b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@gnu@stubs-64.h.blob differ
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@gnu@stubs.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@gnu@stubs.h
new file mode 100644
index 0000000000000000000000000000000000000000..70a1ba017357d3111cc510e73b269541ca2aaf09
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@gnu@stubs.h
@@ -0,0 +1,14 @@
+/* This file is automatically generated.
+   This file selects the right generated file of `__stub_FUNCTION' macros
+   based on the architecture being compiled for.  */
+
+
+#if !defined __x86_64__
+# include <gnu/stubs-32.h>
+#endif
+#if defined __x86_64__ && defined __LP64__
+# include <gnu/stubs-64.h>
+#endif
+#if defined __x86_64__ && defined __ILP32__
+# include <gnu/stubs-x32.h>
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@gnu@stubs.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@gnu@stubs.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@inttypes.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@inttypes.h
new file mode 100644
index 0000000000000000000000000000000000000000..d550769f2aaddc989670879165d6fca9ac3cdd4d
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@inttypes.h
@@ -0,0 +1,316 @@
+/* Copyright (C) 1997-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+/*
+ *	ISO C99: 7.8 Format conversion of integer types	<inttypes.h>
+ */
+
+#ifndef _INTTYPES_H
+#define _INTTYPES_H	1
+
+#include <features.h>
+/* Get the type definitions.  */
+#include <stdint.h>
+
+/* Get a definition for wchar_t.  But we must not define wchar_t itself.  */
+#ifndef ____gwchar_t_defined
+# ifdef __cplusplus
+#  define __gwchar_t wchar_t
+# elif defined __WCHAR_TYPE__
+typedef __WCHAR_TYPE__ __gwchar_t;
+# else
+#  define __need_wchar_t
+#  include <stddef.h>
+typedef wchar_t __gwchar_t;
+# endif
+# define ____gwchar_t_defined	1
+#endif
+
+# if __WORDSIZE == 64
+#  define __PRI64_PREFIX	"l"
+#  define __PRIPTR_PREFIX	"l"
+# else
+#  define __PRI64_PREFIX	"ll"
+#  define __PRIPTR_PREFIX
+# endif
+
+/* Macros for printing format specifiers.  */
+
+/* Decimal notation.  */
+# define PRId8		"d"
+# define PRId16		"d"
+# define PRId32		"d"
+# define PRId64		__PRI64_PREFIX "d"
+
+# define PRIdLEAST8	"d"
+# define PRIdLEAST16	"d"
+# define PRIdLEAST32	"d"
+# define PRIdLEAST64	__PRI64_PREFIX "d"
+
+# define PRIdFAST8	"d"
+# define PRIdFAST16	__PRIPTR_PREFIX "d"
+# define PRIdFAST32	__PRIPTR_PREFIX "d"
+# define PRIdFAST64	__PRI64_PREFIX "d"
+
+
+# define PRIi8		"i"
+# define PRIi16		"i"
+# define PRIi32		"i"
+# define PRIi64		__PRI64_PREFIX "i"
+
+# define PRIiLEAST8	"i"
+# define PRIiLEAST16	"i"
+# define PRIiLEAST32	"i"
+# define PRIiLEAST64	__PRI64_PREFIX "i"
+
+# define PRIiFAST8	"i"
+# define PRIiFAST16	__PRIPTR_PREFIX "i"
+# define PRIiFAST32	__PRIPTR_PREFIX "i"
+# define PRIiFAST64	__PRI64_PREFIX "i"
+
+/* Octal notation.  */
+# define PRIo8		"o"
+# define PRIo16		"o"
+# define PRIo32		"o"
+# define PRIo64		__PRI64_PREFIX "o"
+
+# define PRIoLEAST8	"o"
+# define PRIoLEAST16	"o"
+# define PRIoLEAST32	"o"
+# define PRIoLEAST64	__PRI64_PREFIX "o"
+
+# define PRIoFAST8	"o"
+# define PRIoFAST16	__PRIPTR_PREFIX "o"
+# define PRIoFAST32	__PRIPTR_PREFIX "o"
+# define PRIoFAST64	__PRI64_PREFIX "o"
+
+/* Unsigned integers.  */
+# define PRIu8		"u"
+# define PRIu16		"u"
+# define PRIu32		"u"
+# define PRIu64		__PRI64_PREFIX "u"
+
+# define PRIuLEAST8	"u"
+# define PRIuLEAST16	"u"
+# define PRIuLEAST32	"u"
+# define PRIuLEAST64	__PRI64_PREFIX "u"
+
+# define PRIuFAST8	"u"
+# define PRIuFAST16	__PRIPTR_PREFIX "u"
+# define PRIuFAST32	__PRIPTR_PREFIX "u"
+# define PRIuFAST64	__PRI64_PREFIX "u"
+
+/* lowercase hexadecimal notation.  */
+# define PRIx8		"x"
+# define PRIx16		"x"
+# define PRIx32		"x"
+# define PRIx64		__PRI64_PREFIX "x"
+
+# define PRIxLEAST8	"x"
+# define PRIxLEAST16	"x"
+# define PRIxLEAST32	"x"
+# define PRIxLEAST64	__PRI64_PREFIX "x"
+
+# define PRIxFAST8	"x"
+# define PRIxFAST16	__PRIPTR_PREFIX "x"
+# define PRIxFAST32	__PRIPTR_PREFIX "x"
+# define PRIxFAST64	__PRI64_PREFIX "x"
+
+/* UPPERCASE hexadecimal notation.  */
+# define PRIX8		"X"
+# define PRIX16		"X"
+# define PRIX32		"X"
+# define PRIX64		__PRI64_PREFIX "X"
+
+# define PRIXLEAST8	"X"
+# define PRIXLEAST16	"X"
+# define PRIXLEAST32	"X"
+# define PRIXLEAST64	__PRI64_PREFIX "X"
+
+# define PRIXFAST8	"X"
+# define PRIXFAST16	__PRIPTR_PREFIX "X"
+# define PRIXFAST32	__PRIPTR_PREFIX "X"
+# define PRIXFAST64	__PRI64_PREFIX "X"
+
+
+/* Macros for printing `intmax_t' and `uintmax_t'.  */
+# define PRIdMAX	__PRI64_PREFIX "d"
+# define PRIiMAX	__PRI64_PREFIX "i"
+# define PRIoMAX	__PRI64_PREFIX "o"
+# define PRIuMAX	__PRI64_PREFIX "u"
+# define PRIxMAX	__PRI64_PREFIX "x"
+# define PRIXMAX	__PRI64_PREFIX "X"
+
+
+/* Macros for printing `intptr_t' and `uintptr_t'.  */
+# define PRIdPTR	__PRIPTR_PREFIX "d"
+# define PRIiPTR	__PRIPTR_PREFIX "i"
+# define PRIoPTR	__PRIPTR_PREFIX "o"
+# define PRIuPTR	__PRIPTR_PREFIX "u"
+# define PRIxPTR	__PRIPTR_PREFIX "x"
+# define PRIXPTR	__PRIPTR_PREFIX "X"
+
+
+/* Macros for scanning format specifiers.  */
+
+/* Signed decimal notation.  */
+# define SCNd8		"hhd"
+# define SCNd16		"hd"
+# define SCNd32		"d"
+# define SCNd64		__PRI64_PREFIX "d"
+
+# define SCNdLEAST8	"hhd"
+# define SCNdLEAST16	"hd"
+# define SCNdLEAST32	"d"
+# define SCNdLEAST64	__PRI64_PREFIX "d"
+
+# define SCNdFAST8	"hhd"
+# define SCNdFAST16	__PRIPTR_PREFIX "d"
+# define SCNdFAST32	__PRIPTR_PREFIX "d"
+# define SCNdFAST64	__PRI64_PREFIX "d"
+
+/* Signed decimal notation.  */
+# define SCNi8		"hhi"
+# define SCNi16		"hi"
+# define SCNi32		"i"
+# define SCNi64		__PRI64_PREFIX "i"
+
+# define SCNiLEAST8	"hhi"
+# define SCNiLEAST16	"hi"
+# define SCNiLEAST32	"i"
+# define SCNiLEAST64	__PRI64_PREFIX "i"
+
+# define SCNiFAST8	"hhi"
+# define SCNiFAST16	__PRIPTR_PREFIX "i"
+# define SCNiFAST32	__PRIPTR_PREFIX "i"
+# define SCNiFAST64	__PRI64_PREFIX "i"
+
+/* Unsigned decimal notation.  */
+# define SCNu8		"hhu"
+# define SCNu16		"hu"
+# define SCNu32		"u"
+# define SCNu64		__PRI64_PREFIX "u"
+
+# define SCNuLEAST8	"hhu"
+# define SCNuLEAST16	"hu"
+# define SCNuLEAST32	"u"
+# define SCNuLEAST64	__PRI64_PREFIX "u"
+
+# define SCNuFAST8	"hhu"
+# define SCNuFAST16	__PRIPTR_PREFIX "u"
+# define SCNuFAST32	__PRIPTR_PREFIX "u"
+# define SCNuFAST64	__PRI64_PREFIX "u"
+
+/* Octal notation.  */
+# define SCNo8		"hho"
+# define SCNo16		"ho"
+# define SCNo32		"o"
+# define SCNo64		__PRI64_PREFIX "o"
+
+# define SCNoLEAST8	"hho"
+# define SCNoLEAST16	"ho"
+# define SCNoLEAST32	"o"
+# define SCNoLEAST64	__PRI64_PREFIX "o"
+
+# define SCNoFAST8	"hho"
+# define SCNoFAST16	__PRIPTR_PREFIX "o"
+# define SCNoFAST32	__PRIPTR_PREFIX "o"
+# define SCNoFAST64	__PRI64_PREFIX "o"
+
+/* Hexadecimal notation.  */
+# define SCNx8		"hhx"
+# define SCNx16		"hx"
+# define SCNx32		"x"
+# define SCNx64		__PRI64_PREFIX "x"
+
+# define SCNxLEAST8	"hhx"
+# define SCNxLEAST16	"hx"
+# define SCNxLEAST32	"x"
+# define SCNxLEAST64	__PRI64_PREFIX "x"
+
+# define SCNxFAST8	"hhx"
+# define SCNxFAST16	__PRIPTR_PREFIX "x"
+# define SCNxFAST32	__PRIPTR_PREFIX "x"
+# define SCNxFAST64	__PRI64_PREFIX "x"
+
+
+/* Macros for scanning `intmax_t' and `uintmax_t'.  */
+# define SCNdMAX	__PRI64_PREFIX "d"
+# define SCNiMAX	__PRI64_PREFIX "i"
+# define SCNoMAX	__PRI64_PREFIX "o"
+# define SCNuMAX	__PRI64_PREFIX "u"
+# define SCNxMAX	__PRI64_PREFIX "x"
+
+/* Macros for scaning `intptr_t' and `uintptr_t'.  */
+# define SCNdPTR	__PRIPTR_PREFIX "d"
+# define SCNiPTR	__PRIPTR_PREFIX "i"
+# define SCNoPTR	__PRIPTR_PREFIX "o"
+# define SCNuPTR	__PRIPTR_PREFIX "u"
+# define SCNxPTR	__PRIPTR_PREFIX "x"
+
+
+__BEGIN_DECLS
+
+#if __WORDSIZE == 64
+
+/* We have to define the `uintmax_t' type using `ldiv_t'.  */
+typedef struct
+  {
+    long int quot;		/* Quotient.  */
+    long int rem;		/* Remainder.  */
+  } imaxdiv_t;
+
+#else
+
+/* We have to define the `uintmax_t' type using `lldiv_t'.  */
+typedef struct
+  {
+    __extension__ long long int quot;	/* Quotient.  */
+    __extension__ long long int rem;	/* Remainder.  */
+  } imaxdiv_t;
+
+#endif
+
+
+/* Compute absolute value of N.  */
+extern intmax_t imaxabs (intmax_t __n) __THROW __attribute__ ((__const__));
+
+/* Return the `imaxdiv_t' representation of the value of NUMER over DENOM. */
+extern imaxdiv_t imaxdiv (intmax_t __numer, intmax_t __denom)
+      __THROW __attribute__ ((__const__));
+
+/* Like `strtol' but convert to `intmax_t'.  */
+extern intmax_t strtoimax (const char *__restrict __nptr,
+			   char **__restrict __endptr, int __base) __THROW;
+
+/* Like `strtoul' but convert to `uintmax_t'.  */
+extern uintmax_t strtoumax (const char *__restrict __nptr,
+			    char ** __restrict __endptr, int __base) __THROW;
+
+/* Like `wcstol' but convert to `intmax_t'.  */
+extern intmax_t wcstoimax (const __gwchar_t *__restrict __nptr,
+			   __gwchar_t **__restrict __endptr, int __base)
+     __THROW;
+
+/* Like `wcstoul' but convert to `uintmax_t'.  */
+extern uintmax_t wcstoumax (const __gwchar_t *__restrict __nptr,
+			    __gwchar_t ** __restrict __endptr, int __base)
+     __THROW;
+
+__END_DECLS
+
+#endif /* inttypes.h */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@inttypes.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@inttypes.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@libintl.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@libintl.h
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index 0000000000000000000000000000000000000000..22f79b248cacee6d9c3a793a1211b63375fe64c4
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@libintl.h
@@ -0,0 +1,123 @@
+/* Message catalogs for internationalization.
+   Copyright (C) 1995-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   This file is derived from the file libgettext.h in the GNU gettext package.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _LIBINTL_H
+#define _LIBINTL_H	1
+
+#include <features.h>
+
+/* We define an additional symbol to signal that we use the GNU
+   implementation of gettext.  */
+#define __USE_GNU_GETTEXT 1
+
+/* Provide information about the supported file formats.  Returns the
+   maximum minor revision number supported for a given major revision.  */
+#define __GNU_GETTEXT_SUPPORTED_REVISION(major) \
+  ((major) == 0 ? 1 : -1)
+
+__BEGIN_DECLS
+
+/* Look up MSGID in the current default message catalog for the current
+   LC_MESSAGES locale.  If not found, returns MSGID itself (the default
+   text).  */
+extern char *gettext (const char *__msgid)
+     __THROW __attribute_format_arg__ (1);
+
+/* Look up MSGID in the DOMAINNAME message catalog for the current
+   LC_MESSAGES locale.  */
+extern char *dgettext (const char *__domainname, const char *__msgid)
+     __THROW __attribute_format_arg__ (2);
+extern char *__dgettext (const char *__domainname, const char *__msgid)
+     __THROW __attribute_format_arg__ (2);
+
+/* Look up MSGID in the DOMAINNAME message catalog for the current CATEGORY
+   locale.  */
+extern char *dcgettext (const char *__domainname,
+			const char *__msgid, int __category)
+     __THROW __attribute_format_arg__ (2);
+extern char *__dcgettext (const char *__domainname,
+			  const char *__msgid, int __category)
+     __THROW __attribute_format_arg__ (2);
+
+
+/* Similar to `gettext' but select the plural form corresponding to the
+   number N.  */
+extern char *ngettext (const char *__msgid1, const char *__msgid2,
+		       unsigned long int __n)
+     __THROW __attribute_format_arg__ (1) __attribute_format_arg__ (2);
+
+/* Similar to `dgettext' but select the plural form corresponding to the
+   number N.  */
+extern char *dngettext (const char *__domainname, const char *__msgid1,
+			const char *__msgid2, unsigned long int __n)
+     __THROW __attribute_format_arg__ (2) __attribute_format_arg__ (3);
+
+/* Similar to `dcgettext' but select the plural form corresponding to the
+   number N.  */
+extern char *dcngettext (const char *__domainname, const char *__msgid1,
+			 const char *__msgid2, unsigned long int __n,
+			 int __category)
+     __THROW __attribute_format_arg__ (2) __attribute_format_arg__ (3);
+
+
+/* Set the current default message catalog to DOMAINNAME.
+   If DOMAINNAME is null, return the current default.
+   If DOMAINNAME is "", reset to the default of "messages".  */
+extern char *textdomain (const char *__domainname) __THROW;
+
+/* Specify that the DOMAINNAME message catalog will be found
+   in DIRNAME rather than in the system locale data base.  */
+extern char *bindtextdomain (const char *__domainname,
+			     const char *__dirname) __THROW;
+
+/* Specify the character encoding in which the messages from the
+   DOMAINNAME message catalog will be returned.  */
+extern char *bind_textdomain_codeset (const char *__domainname,
+				      const char *__codeset) __THROW;
+
+
+/* Optimized version of the function above.  */
+#if defined __OPTIMIZE__ && !defined __cplusplus
+
+/* We need NULL for `gettext'.  */
+# define __need_NULL
+# include <stddef.h>
+
+/* We need LC_MESSAGES for `dgettext'.  */
+# include <locale.h>
+
+/* These must be macros.  Inlined functions are useless because the
+   `__builtin_constant_p' predicate in dcgettext would always return
+   false.  */
+
+# define gettext(msgid) dgettext (NULL, msgid)
+
+# define dgettext(domainname, msgid) \
+  dcgettext (domainname, msgid, LC_MESSAGES)
+
+# define ngettext(msgid1, msgid2, n) dngettext (NULL, msgid1, msgid2, n)
+
+# define dngettext(domainname, msgid1, msgid2, n) \
+  dcngettext (domainname, msgid1, msgid2, n, LC_MESSAGES)
+
+#endif	/* Optimizing.  */
+
+__END_DECLS
+
+#endif /* libintl.h */
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@limits.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@limits.h
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@@ -0,0 +1,204 @@
+/* Copyright (C) 1991-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+/*
+ *	ISO C99 Standard: 7.10/5.2.4.2.1 Sizes of integer types	<limits.h>
+ */
+
+#ifndef _LIBC_LIMITS_H_
+#define _LIBC_LIMITS_H_	1
+
+#define __GLIBC_INTERNAL_STARTING_HEADER_IMPLEMENTATION
+#include <bits/libc-header-start.h>
+
+
+/* Maximum length of any multibyte character in any locale.
+   We define this value here since the gcc header does not define
+   the correct value.  */
+#define MB_LEN_MAX	16
+
+
+/* If we are not using GNU CC we have to define all the symbols ourself.
+   Otherwise use gcc's definitions (see below).  */
+#if !defined __GNUC__ || __GNUC__ < 2
+
+/* We only protect from multiple inclusion here, because all the other
+   #include's protect themselves, and in GCC 2 we may #include_next through
+   multiple copies of this file before we get to GCC's.  */
+# ifndef _LIMITS_H
+#  define _LIMITS_H	1
+
+#include <bits/wordsize.h>
+
+/* We don't have #include_next.
+   Define ANSI <limits.h> for standard 32-bit words.  */
+
+/* These assume 8-bit `char's, 16-bit `short int's,
+   and 32-bit `int's and `long int's.  */
+
+/* Number of bits in a `char'.	*/
+#  define CHAR_BIT	8
+
+/* Minimum and maximum values a `signed char' can hold.  */
+#  define SCHAR_MIN	(-128)
+#  define SCHAR_MAX	127
+
+/* Maximum value an `unsigned char' can hold.  (Minimum is 0.)  */
+#  define UCHAR_MAX	255
+
+/* Minimum and maximum values a `char' can hold.  */
+#  ifdef __CHAR_UNSIGNED__
+#   define CHAR_MIN	0
+#   define CHAR_MAX	UCHAR_MAX
+#  else
+#   define CHAR_MIN	SCHAR_MIN
+#   define CHAR_MAX	SCHAR_MAX
+#  endif
+
+/* Minimum and maximum values a `signed short int' can hold.  */
+#  define SHRT_MIN	(-32768)
+#  define SHRT_MAX	32767
+
+/* Maximum value an `unsigned short int' can hold.  (Minimum is 0.)  */
+#  define USHRT_MAX	65535
+
+/* Minimum and maximum values a `signed int' can hold.  */
+#  define INT_MIN	(-INT_MAX - 1)
+#  define INT_MAX	2147483647
+
+/* Maximum value an `unsigned int' can hold.  (Minimum is 0.)  */
+#  define UINT_MAX	4294967295U
+
+/* Minimum and maximum values a `signed long int' can hold.  */
+#  if __WORDSIZE == 64
+#   define LONG_MAX	9223372036854775807L
+#  else
+#   define LONG_MAX	2147483647L
+#  endif
+#  define LONG_MIN	(-LONG_MAX - 1L)
+
+/* Maximum value an `unsigned long int' can hold.  (Minimum is 0.)  */
+#  if __WORDSIZE == 64
+#   define ULONG_MAX	18446744073709551615UL
+#  else
+#   define ULONG_MAX	4294967295UL
+#  endif
+
+#  ifdef __USE_ISOC99
+
+/* Minimum and maximum values a `signed long long int' can hold.  */
+#   define LLONG_MAX	9223372036854775807LL
+#   define LLONG_MIN	(-LLONG_MAX - 1LL)
+
+/* Maximum value an `unsigned long long int' can hold.  (Minimum is 0.)  */
+#   define ULLONG_MAX	18446744073709551615ULL
+
+#  endif /* ISO C99 */
+
+# endif	/* limits.h  */
+#endif	/* GCC 2.  */
+
+#endif	/* !_LIBC_LIMITS_H_ */
+
+ /* Get the compiler's limits.h, which defines almost all the ISO constants.
+
+    We put this #include_next outside the double inclusion check because
+    it should be possible to include this file more than once and still get
+    the definitions from gcc's header.  */
+#if defined __GNUC__ && !defined _GCC_LIMITS_H_
+/* `_GCC_LIMITS_H_' is what GCC's file defines.  */
+# include_next <limits.h>
+#endif
+
+/* The <limits.h> files in some gcc versions don't define LLONG_MIN,
+   LLONG_MAX, and ULLONG_MAX.  Instead only the values gcc defined for
+   ages are available.  */
+#if defined __USE_ISOC99 && defined __GNUC__
+# ifndef LLONG_MIN
+#  define LLONG_MIN	(-LLONG_MAX-1)
+# endif
+# ifndef LLONG_MAX
+#  define LLONG_MAX	__LONG_LONG_MAX__
+# endif
+# ifndef ULLONG_MAX
+#  define ULLONG_MAX	(LLONG_MAX * 2ULL + 1)
+# endif
+#endif
+
+/* The integer width macros are not defined by GCC's <limits.h> before
+   GCC 7, or if _GNU_SOURCE rather than
+   __STDC_WANT_IEC_60559_BFP_EXT__ is used to enable this feature.  */
+#if __GLIBC_USE (IEC_60559_BFP_EXT_C2X)
+# ifndef CHAR_WIDTH
+#  define CHAR_WIDTH 8
+# endif
+# ifndef SCHAR_WIDTH
+#  define SCHAR_WIDTH 8
+# endif
+# ifndef UCHAR_WIDTH
+#  define UCHAR_WIDTH 8
+# endif
+# ifndef SHRT_WIDTH
+#  define SHRT_WIDTH 16
+# endif
+# ifndef USHRT_WIDTH
+#  define USHRT_WIDTH 16
+# endif
+# ifndef INT_WIDTH
+#  define INT_WIDTH 32
+# endif
+# ifndef UINT_WIDTH
+#  define UINT_WIDTH 32
+# endif
+# ifndef LONG_WIDTH
+#  define LONG_WIDTH __WORDSIZE
+# endif
+# ifndef ULONG_WIDTH
+#  define ULONG_WIDTH __WORDSIZE
+# endif
+# ifndef LLONG_WIDTH
+#  define LLONG_WIDTH 64
+# endif
+# ifndef ULLONG_WIDTH
+#  define ULLONG_WIDTH 64
+# endif
+#endif /* Use IEC_60559_BFP_EXT.  */
+
+/* The macros for _Bool are not defined by GCC's <limits.h> before GCC
+   11, or if _GNU_SOURCE is defined rather than enabling C2x support
+   with -std.  */
+#if __GLIBC_USE (ISOC2X)
+# ifndef BOOL_MAX
+#  define BOOL_MAX 1
+# endif
+# ifndef BOOL_WIDTH
+#  define BOOL_WIDTH 1
+# endif
+#endif
+
+#ifdef	__USE_POSIX
+/* POSIX adds things to <limits.h>.  */
+# include <bits/posix1_lim.h>
+#endif
+
+#ifdef	__USE_POSIX2
+# include <bits/posix2_lim.h>
+#endif
+
+#ifdef	__USE_XOPEN
+# include <bits/xopen_lim.h>
+#endif
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@locale.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@locale.h
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@locale.h
@@ -0,0 +1,197 @@
+/* Copyright (C) 1991-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+/*
+ *	ISO C99 Standard: 7.11 Localization	<locale.h>
+ */
+
+#ifndef	_LOCALE_H
+#define	_LOCALE_H	1
+
+#include <features.h>
+
+#define __need_NULL
+#include <stddef.h>
+#include <bits/locale.h>
+
+__BEGIN_DECLS
+
+/* These are the possibilities for the first argument to setlocale.
+   The code assumes that the lowest LC_* symbol has the value zero.  */
+#define LC_CTYPE          __LC_CTYPE
+#define LC_NUMERIC        __LC_NUMERIC
+#define LC_TIME           __LC_TIME
+#define LC_COLLATE        __LC_COLLATE
+#define LC_MONETARY       __LC_MONETARY
+#define LC_MESSAGES       __LC_MESSAGES
+#define	LC_ALL		  __LC_ALL
+#define LC_PAPER	  __LC_PAPER
+#define LC_NAME		  __LC_NAME
+#define LC_ADDRESS	  __LC_ADDRESS
+#define LC_TELEPHONE	  __LC_TELEPHONE
+#define LC_MEASUREMENT	  __LC_MEASUREMENT
+#define LC_IDENTIFICATION __LC_IDENTIFICATION
+
+
+/* Structure giving information about numeric and monetary notation.  */
+struct lconv
+{
+  /* Numeric (non-monetary) information.  */
+
+  char *decimal_point;		/* Decimal point character.  */
+  char *thousands_sep;		/* Thousands separator.  */
+  /* Each element is the number of digits in each group;
+     elements with higher indices are farther left.
+     An element with value CHAR_MAX means that no further grouping is done.
+     An element with value 0 means that the previous element is used
+     for all groups farther left.  */
+  char *grouping;
+
+  /* Monetary information.  */
+
+  /* First three chars are a currency symbol from ISO 4217.
+     Fourth char is the separator.  Fifth char is '\0'.  */
+  char *int_curr_symbol;
+  char *currency_symbol;	/* Local currency symbol.  */
+  char *mon_decimal_point;	/* Decimal point character.  */
+  char *mon_thousands_sep;	/* Thousands separator.  */
+  char *mon_grouping;		/* Like `grouping' element (above).  */
+  char *positive_sign;		/* Sign for positive values.  */
+  char *negative_sign;		/* Sign for negative values.  */
+  char int_frac_digits;		/* Int'l fractional digits.  */
+  char frac_digits;		/* Local fractional digits.  */
+  /* 1 if currency_symbol precedes a positive value, 0 if succeeds.  */
+  char p_cs_precedes;
+  /* 1 iff a space separates currency_symbol from a positive value.  */
+  char p_sep_by_space;
+  /* 1 if currency_symbol precedes a negative value, 0 if succeeds.  */
+  char n_cs_precedes;
+  /* 1 iff a space separates currency_symbol from a negative value.  */
+  char n_sep_by_space;
+  /* Positive and negative sign positions:
+     0 Parentheses surround the quantity and currency_symbol.
+     1 The sign string precedes the quantity and currency_symbol.
+     2 The sign string follows the quantity and currency_symbol.
+     3 The sign string immediately precedes the currency_symbol.
+     4 The sign string immediately follows the currency_symbol.  */
+  char p_sign_posn;
+  char n_sign_posn;
+#ifdef __USE_ISOC99
+  /* 1 if int_curr_symbol precedes a positive value, 0 if succeeds.  */
+  char int_p_cs_precedes;
+  /* 1 iff a space separates int_curr_symbol from a positive value.  */
+  char int_p_sep_by_space;
+  /* 1 if int_curr_symbol precedes a negative value, 0 if succeeds.  */
+  char int_n_cs_precedes;
+  /* 1 iff a space separates int_curr_symbol from a negative value.  */
+  char int_n_sep_by_space;
+  /* Positive and negative sign positions:
+     0 Parentheses surround the quantity and int_curr_symbol.
+     1 The sign string precedes the quantity and int_curr_symbol.
+     2 The sign string follows the quantity and int_curr_symbol.
+     3 The sign string immediately precedes the int_curr_symbol.
+     4 The sign string immediately follows the int_curr_symbol.  */
+  char int_p_sign_posn;
+  char int_n_sign_posn;
+#else
+  char __int_p_cs_precedes;
+  char __int_p_sep_by_space;
+  char __int_n_cs_precedes;
+  char __int_n_sep_by_space;
+  char __int_p_sign_posn;
+  char __int_n_sign_posn;
+#endif
+};
+
+
+/* Set and/or return the current locale.  */
+extern char *setlocale (int __category, const char *__locale) __THROW;
+
+/* Return the numeric/monetary information for the current locale.  */
+extern struct lconv *localeconv (void) __THROW;
+
+
+#ifdef	__USE_XOPEN2K8
+/* POSIX.1-2008 extends the locale interface with functions for
+   explicit creation and manipulation of 'locale_t' objects
+   representing locale contexts, and a set of parallel
+   locale-sensitive text processing functions that take a locale_t
+   argument.  This enables applications to work with data from
+   multiple locales simultaneously and thread-safely.  */
+# include <bits/types/locale_t.h>
+
+/* Return a reference to a data structure representing a set of locale
+   datasets.  Unlike for the CATEGORY parameter for `setlocale' the
+   CATEGORY_MASK parameter here uses a single bit for each category,
+   made by OR'ing together LC_*_MASK bits above.  */
+extern locale_t newlocale (int __category_mask, const char *__locale,
+			   locale_t __base) __THROW;
+
+/* These are the bits that can be set in the CATEGORY_MASK argument to
+   `newlocale'.  In the GNU implementation, LC_FOO_MASK has the value
+   of (1 << LC_FOO), but this is not a part of the interface that
+   callers can assume will be true.  */
+# define LC_CTYPE_MASK		(1 << __LC_CTYPE)
+# define LC_NUMERIC_MASK	(1 << __LC_NUMERIC)
+# define LC_TIME_MASK		(1 << __LC_TIME)
+# define LC_COLLATE_MASK	(1 << __LC_COLLATE)
+# define LC_MONETARY_MASK	(1 << __LC_MONETARY)
+# define LC_MESSAGES_MASK	(1 << __LC_MESSAGES)
+# define LC_PAPER_MASK		(1 << __LC_PAPER)
+# define LC_NAME_MASK		(1 << __LC_NAME)
+# define LC_ADDRESS_MASK	(1 << __LC_ADDRESS)
+# define LC_TELEPHONE_MASK	(1 << __LC_TELEPHONE)
+# define LC_MEASUREMENT_MASK	(1 << __LC_MEASUREMENT)
+# define LC_IDENTIFICATION_MASK	(1 << __LC_IDENTIFICATION)
+# define LC_ALL_MASK		(LC_CTYPE_MASK \
+				 | LC_NUMERIC_MASK \
+				 | LC_TIME_MASK \
+				 | LC_COLLATE_MASK \
+				 | LC_MONETARY_MASK \
+				 | LC_MESSAGES_MASK \
+				 | LC_PAPER_MASK \
+				 | LC_NAME_MASK \
+				 | LC_ADDRESS_MASK \
+				 | LC_TELEPHONE_MASK \
+				 | LC_MEASUREMENT_MASK \
+				 | LC_IDENTIFICATION_MASK \
+				 )
+
+/* Return a duplicate of the set of locale in DATASET.  All usage
+   counters are increased if necessary.  */
+extern locale_t duplocale (locale_t __dataset) __THROW;
+
+/* Free the data associated with a locale dataset previously returned
+   by a call to `setlocale_r'.  */
+extern void freelocale (locale_t __dataset) __THROW;
+
+/* Switch the current thread's locale to DATASET.
+   If DATASET is null, instead just return the current setting.
+   The special value LC_GLOBAL_LOCALE is the initial setting
+   for all threads and can also be installed any time, meaning
+   the thread uses the global settings controlled by `setlocale'.  */
+extern locale_t uselocale (locale_t __dataset) __THROW;
+
+/* This value can be passed to `uselocale' and may be returned by it.
+   Passing this value to any other function has undefined behavior.  */
+# define LC_GLOBAL_LOCALE	((locale_t) -1L)
+
+#endif
+
+__END_DECLS
+
+#endif /* locale.h  */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@locale.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@locale.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@math.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@math.h
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@@ -0,0 +1,1426 @@
+/* Declarations for math functions.
+   Copyright (C) 1991-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+/*
+ *	ISO C99 Standard: 7.12 Mathematics	<math.h>
+ */
+
+#ifndef	_MATH_H
+#define	_MATH_H	1
+
+#define __GLIBC_INTERNAL_STARTING_HEADER_IMPLEMENTATION
+#include <bits/libc-header-start.h>
+
+#if defined log && defined __GNUC__
+# warning A macro called log was already defined when <math.h> was included.
+# warning This will cause compilation problems.
+#endif
+
+__BEGIN_DECLS
+
+/* Get definitions of __intmax_t and __uintmax_t.  */
+#include <bits/types.h>
+
+/* Get machine-dependent vector math functions declarations.  */
+#include <bits/math-vector.h>
+
+/* Gather machine dependent type support.  */
+#include <bits/floatn.h>
+
+/* Value returned on overflow.  With IEEE 754 floating point, this is
+   +Infinity, otherwise the largest representable positive value.  */
+#if __GNUC_PREREQ (3, 3)
+# define HUGE_VAL (__builtin_huge_val ())
+#else
+/* This may provoke compiler warnings, and may not be rounded to
+   +Infinity in all IEEE 754 rounding modes, but is the best that can
+   be done in ISO C while remaining a constant expression.  10,000 is
+   greater than the maximum (decimal) exponent for all supported
+   floating-point formats and widths.  */
+# define HUGE_VAL 1e10000
+#endif
+#ifdef __USE_ISOC99
+# if __GNUC_PREREQ (3, 3)
+#  define HUGE_VALF (__builtin_huge_valf ())
+#  define HUGE_VALL (__builtin_huge_vall ())
+# else
+#  define HUGE_VALF 1e10000f
+#  define HUGE_VALL 1e10000L
+# endif
+#endif
+#if __HAVE_FLOAT16 && __GLIBC_USE (IEC_60559_TYPES_EXT)
+# define HUGE_VAL_F16 (__builtin_huge_valf16 ())
+#endif
+#if __HAVE_FLOAT32 && __GLIBC_USE (IEC_60559_TYPES_EXT)
+# define HUGE_VAL_F32 (__builtin_huge_valf32 ())
+#endif
+#if __HAVE_FLOAT64 && __GLIBC_USE (IEC_60559_TYPES_EXT)
+# define HUGE_VAL_F64 (__builtin_huge_valf64 ())
+#endif
+#if __HAVE_FLOAT128 && __GLIBC_USE (IEC_60559_TYPES_EXT)
+# define HUGE_VAL_F128 (__builtin_huge_valf128 ())
+#endif
+#if __HAVE_FLOAT32X && __GLIBC_USE (IEC_60559_TYPES_EXT)
+# define HUGE_VAL_F32X (__builtin_huge_valf32x ())
+#endif
+#if __HAVE_FLOAT64X && __GLIBC_USE (IEC_60559_TYPES_EXT)
+# define HUGE_VAL_F64X (__builtin_huge_valf64x ())
+#endif
+#if __HAVE_FLOAT128X && __GLIBC_USE (IEC_60559_TYPES_EXT)
+# define HUGE_VAL_F128X (__builtin_huge_valf128x ())
+#endif
+
+#ifdef __USE_ISOC99
+/* IEEE positive infinity.  */
+# if __GNUC_PREREQ (3, 3)
+#  define INFINITY (__builtin_inff ())
+# else
+#  define INFINITY HUGE_VALF
+# endif
+
+/* IEEE Not A Number.  */
+# if __GNUC_PREREQ (3, 3)
+#  define NAN (__builtin_nanf (""))
+# else
+/* This will raise an "invalid" exception outside static initializers,
+   but is the best that can be done in ISO C while remaining a
+   constant expression.  */
+#  define NAN (0.0f / 0.0f)
+# endif
+#endif /* __USE_ISOC99 */
+
+#if __GLIBC_USE (IEC_60559_BFP_EXT)
+/* Signaling NaN macros, if supported.  */
+# if __GNUC_PREREQ (3, 3)
+#  define SNANF (__builtin_nansf (""))
+#  define SNAN (__builtin_nans (""))
+#  define SNANL (__builtin_nansl (""))
+# endif
+#endif
+#if (__HAVE_FLOAT16					\
+     && __GLIBC_USE (IEC_60559_TYPES_EXT)		\
+     && (defined __USE_GNU || !__GLIBC_USE (ISOC2X)))
+# define SNANF16 (__builtin_nansf16 (""))
+#endif
+#if (__HAVE_FLOAT32					\
+     && __GLIBC_USE (IEC_60559_TYPES_EXT)		\
+     && (defined __USE_GNU || !__GLIBC_USE (ISOC2X)))
+# define SNANF32 (__builtin_nansf32 (""))
+#endif
+#if (__HAVE_FLOAT64					\
+     && __GLIBC_USE (IEC_60559_TYPES_EXT)		\
+     && (defined __USE_GNU || !__GLIBC_USE (ISOC2X)))
+# define SNANF64 (__builtin_nansf64 (""))
+#endif
+#if (__HAVE_FLOAT128					\
+     && __GLIBC_USE (IEC_60559_TYPES_EXT)		\
+     && (defined __USE_GNU || !__GLIBC_USE (ISOC2X)))
+# define SNANF128 (__builtin_nansf128 (""))
+#endif
+#if (__HAVE_FLOAT32X					\
+     && __GLIBC_USE (IEC_60559_TYPES_EXT)		\
+     && (defined __USE_GNU || !__GLIBC_USE (ISOC2X)))
+# define SNANF32X (__builtin_nansf32x (""))
+#endif
+#if (__HAVE_FLOAT64X					\
+     && __GLIBC_USE (IEC_60559_TYPES_EXT)		\
+     && (defined __USE_GNU || !__GLIBC_USE (ISOC2X)))
+# define SNANF64X (__builtin_nansf64x (""))
+#endif
+#if (__HAVE_FLOAT128X					\
+     && __GLIBC_USE (IEC_60559_TYPES_EXT)		\
+     && (defined __USE_GNU || !__GLIBC_USE (ISOC2X)))
+# define SNANF128X (__builtin_nansf128x (""))
+#endif
+
+/* Get __GLIBC_FLT_EVAL_METHOD.  */
+#include <bits/flt-eval-method.h>
+
+#ifdef __USE_ISOC99
+/* Define the following typedefs.
+
+    float_t	floating-point type at least as wide as `float' used
+		to evaluate `float' expressions
+    double_t	floating-point type at least as wide as `double' used
+		to evaluate `double' expressions
+*/
+# if __GLIBC_FLT_EVAL_METHOD == 0 || __GLIBC_FLT_EVAL_METHOD == 16
+typedef float float_t;
+typedef double double_t;
+# elif __GLIBC_FLT_EVAL_METHOD == 1
+typedef double float_t;
+typedef double double_t;
+# elif __GLIBC_FLT_EVAL_METHOD == 2
+typedef long double float_t;
+typedef long double double_t;
+# elif __GLIBC_FLT_EVAL_METHOD == 32
+typedef _Float32 float_t;
+typedef double double_t;
+# elif __GLIBC_FLT_EVAL_METHOD == 33
+typedef _Float32x float_t;
+typedef _Float32x double_t;
+# elif __GLIBC_FLT_EVAL_METHOD == 64
+typedef _Float64 float_t;
+typedef _Float64 double_t;
+# elif __GLIBC_FLT_EVAL_METHOD == 65
+typedef _Float64x float_t;
+typedef _Float64x double_t;
+# elif __GLIBC_FLT_EVAL_METHOD == 128
+typedef _Float128 float_t;
+typedef _Float128 double_t;
+# elif __GLIBC_FLT_EVAL_METHOD == 129
+typedef _Float128x float_t;
+typedef _Float128x double_t;
+# else
+#  error "Unknown __GLIBC_FLT_EVAL_METHOD"
+# endif
+#endif
+
+/* Define macros for the return values of ilogb and llogb, based on
+   __FP_LOGB0_IS_MIN and __FP_LOGBNAN_IS_MIN.
+
+    FP_ILOGB0	Expands to a value returned by `ilogb (0.0)'.
+    FP_ILOGBNAN	Expands to a value returned by `ilogb (NAN)'.
+    FP_LLOGB0	Expands to a value returned by `llogb (0.0)'.
+    FP_LLOGBNAN	Expands to a value returned by `llogb (NAN)'.
+
+*/
+
+#include <bits/fp-logb.h>
+#ifdef __USE_ISOC99
+# if __FP_LOGB0_IS_MIN
+#  define FP_ILOGB0	(-2147483647 - 1)
+# else
+#  define FP_ILOGB0	(-2147483647)
+# endif
+# if __FP_LOGBNAN_IS_MIN
+#  define FP_ILOGBNAN	(-2147483647 - 1)
+# else
+#  define FP_ILOGBNAN	2147483647
+# endif
+#endif
+#if __GLIBC_USE (IEC_60559_BFP_EXT_C2X)
+# if __WORDSIZE == 32
+#  define __FP_LONG_MAX 0x7fffffffL
+# else
+#  define __FP_LONG_MAX 0x7fffffffffffffffL
+# endif
+# if __FP_LOGB0_IS_MIN
+#  define FP_LLOGB0	(-__FP_LONG_MAX - 1)
+# else
+#  define FP_LLOGB0	(-__FP_LONG_MAX)
+# endif
+# if __FP_LOGBNAN_IS_MIN
+#  define FP_LLOGBNAN	(-__FP_LONG_MAX - 1)
+# else
+#  define FP_LLOGBNAN	__FP_LONG_MAX
+# endif
+#endif
+
+/* Get the architecture specific values describing the floating-point
+   evaluation.  The following symbols will get defined:
+
+    FP_FAST_FMA
+    FP_FAST_FMAF
+    FP_FAST_FMAL
+		If defined it indicates that the `fma' function
+		generally executes about as fast as a multiply and an add.
+		This macro is defined only iff the `fma' function is
+		implemented directly with a hardware multiply-add instructions.
+*/
+
+#include <bits/fp-fast.h>
+
+#if __GLIBC_USE (IEC_60559_BFP_EXT_C2X)
+/* Rounding direction macros for fromfp functions.  */
+enum
+  {
+    FP_INT_UPWARD =
+# define FP_INT_UPWARD 0
+      FP_INT_UPWARD,
+    FP_INT_DOWNWARD =
+# define FP_INT_DOWNWARD 1
+      FP_INT_DOWNWARD,
+    FP_INT_TOWARDZERO =
+# define FP_INT_TOWARDZERO 2
+      FP_INT_TOWARDZERO,
+    FP_INT_TONEARESTFROMZERO =
+# define FP_INT_TONEARESTFROMZERO 3
+      FP_INT_TONEARESTFROMZERO,
+    FP_INT_TONEAREST =
+# define FP_INT_TONEAREST 4
+      FP_INT_TONEAREST,
+  };
+#endif
+
+/* The file <bits/mathcalls.h> contains the prototypes for all the
+   actual math functions.  These macros are used for those prototypes,
+   so we can easily declare each function as both `name' and `__name',
+   and can declare the float versions `namef' and `__namef'.  */
+
+#define __SIMD_DECL(function) __CONCAT (__DECL_SIMD_, function)
+
+#define __MATHCALL_VEC(function, suffix, args) 	\
+  __SIMD_DECL (__MATH_PRECNAME (function, suffix)) \
+  __MATHCALL (function, suffix, args)
+
+#define __MATHDECL_VEC(type, function,suffix, args) \
+  __SIMD_DECL (__MATH_PRECNAME (function, suffix)) \
+  __MATHDECL(type, function,suffix, args)
+
+#define __MATHCALL(function,suffix, args)	\
+  __MATHDECL (_Mdouble_,function,suffix, args)
+#define __MATHDECL(type, function,suffix, args) \
+  __MATHDECL_1(type, function,suffix, args); \
+  __MATHDECL_1(type, __CONCAT(__,function),suffix, args)
+#define __MATHCALLX(function,suffix, args, attrib)	\
+  __MATHDECLX (_Mdouble_,function,suffix, args, attrib)
+#define __MATHDECLX(type, function,suffix, args, attrib) \
+  __MATHDECL_1(type, function,suffix, args) __attribute__ (attrib); \
+  __MATHDECL_1(type, __CONCAT(__,function),suffix, args) __attribute__ (attrib)
+#define __MATHDECL_1_IMPL(type, function, suffix, args) \
+  extern type __MATH_PRECNAME(function,suffix) args __THROW
+#define __MATHDECL_1(type, function, suffix, args) \
+  __MATHDECL_1_IMPL(type, function, suffix, args)
+/* Ignore the alias by default.  The alias is only useful with
+   redirections.  */
+#define __MATHDECL_ALIAS(type, function, suffix, args, alias) \
+  __MATHDECL_1(type, function, suffix, args)
+
+#define __MATHREDIR(type, function, suffix, args, to) \
+  extern type __REDIRECT_NTH (__MATH_PRECNAME (function, suffix), args, to)
+
+#define _Mdouble_		double
+#define __MATH_PRECNAME(name,r)	__CONCAT(name,r)
+#define __MATH_DECLARING_DOUBLE  1
+#define __MATH_DECLARING_FLOATN  0
+#include <bits/mathcalls-helper-functions.h>
+#include <bits/mathcalls.h>
+#undef	_Mdouble_
+#undef	__MATH_PRECNAME
+#undef __MATH_DECLARING_DOUBLE
+#undef __MATH_DECLARING_FLOATN
+
+#ifdef __USE_ISOC99
+
+
+/* Include the file of declarations again, this time using `float'
+   instead of `double' and appending f to each function name.  */
+
+# define _Mdouble_		float
+# define __MATH_PRECNAME(name,r) name##f##r
+# define __MATH_DECLARING_DOUBLE  0
+# define __MATH_DECLARING_FLOATN  0
+# include <bits/mathcalls-helper-functions.h>
+# include <bits/mathcalls.h>
+# undef	_Mdouble_
+# undef	__MATH_PRECNAME
+# undef __MATH_DECLARING_DOUBLE
+# undef __MATH_DECLARING_FLOATN
+
+# if !(defined __NO_LONG_DOUBLE_MATH && defined _LIBC) \
+     || defined __LDBL_COMPAT \
+     || defined _LIBC_TEST
+#  ifdef __LDBL_COMPAT
+
+#   ifdef __USE_ISOC99
+extern float __nldbl_nexttowardf (float __x, long double __y)
+				  __THROW __attribute__ ((__const__));
+#    ifdef __REDIRECT_NTH
+extern float __REDIRECT_NTH (nexttowardf, (float __x, long double __y),
+			     __nldbl_nexttowardf)
+     __attribute__ ((__const__));
+extern double __REDIRECT_NTH (nexttoward, (double __x, long double __y),
+			      nextafter) __attribute__ ((__const__));
+extern long double __REDIRECT_NTH (nexttowardl,
+				   (long double __x, long double __y),
+				   nextafter) __attribute__ ((__const__));
+#    endif
+#   endif
+
+#   undef __MATHDECL_1
+#   define __MATHDECL_1(type, function,suffix, args) \
+  __MATHREDIR(type, function, suffix, args, __CONCAT(function,suffix))
+
+#  elif __LDOUBLE_REDIRECTS_TO_FLOAT128_ABI == 1
+#   ifdef __REDIRECT_NTH
+#    ifdef __USE_ISOC99
+extern float __REDIRECT_NTH (nexttowardf, (float __x, long double __y),
+			    __nexttowardf_to_ieee128)
+  __attribute__ ((__const__));
+extern double __REDIRECT_NTH (nexttoward, (double __x, long double __y),
+			     __nexttoward_to_ieee128)
+  __attribute__ ((__const__));
+
+#define __dremieee128 __remainderieee128
+#define __gammaieee128 __lgammaieee128
+
+#    endif
+#   endif
+
+#   undef __MATHDECL_1
+#   undef __MATHDECL_ALIAS
+
+#   define __REDIRTO(function, suffix) \
+  __ ## function ## ieee128 ## suffix
+#   define __REDIRTO_ALT(function, suffix) \
+  __ ## function ## f128 ## suffix
+
+#   define __MATHDECL_1(type, function, suffix, args) \
+  __MATHREDIR (type, function, suffix, args, __REDIRTO (function, suffix))
+#   define __MATHDECL_ALIAS(type, function, suffix, args, alias) \
+  __MATHREDIR (type, function, suffix, args, __REDIRTO_ALT (alias, suffix))
+#  endif
+
+/* Include the file of declarations again, this time using `long double'
+   instead of `double' and appending l to each function name.  */
+
+#  define _Mdouble_		long double
+#  define __MATH_PRECNAME(name,r) name##l##r
+#  define __MATH_DECLARING_DOUBLE  0
+#  define __MATH_DECLARING_FLOATN  0
+#  define __MATH_DECLARE_LDOUBLE   1
+#  include <bits/mathcalls-helper-functions.h>
+#  include <bits/mathcalls.h>
+
+#  undef _Mdouble_
+#  undef __MATH_PRECNAME
+#  undef __MATH_DECLARING_DOUBLE
+#  undef __MATH_DECLARING_FLOATN
+
+#  if defined __LDBL_COMPAT \
+      || __LDOUBLE_REDIRECTS_TO_FLOAT128_ABI == 1
+#   undef __REDIRTO
+#   undef __REDIRTO_ALT
+#   undef __MATHDECL_1
+#   undef __MATHDECL_ALIAS
+#   define __MATHDECL_1(type, function, suffix, args) \
+  __MATHDECL_1_IMPL(type, function, suffix, args)
+#   define __MATHDECL_ALIAS(type, function, suffix, args, alias) \
+  __MATHDECL_1(type, function, suffix, args)
+#  endif
+# endif /* !(__NO_LONG_DOUBLE_MATH && _LIBC) || __LDBL_COMPAT */
+
+#endif	/* Use ISO C99.  */
+
+/* Include the file of declarations for _FloatN and _FloatNx
+   types.  */
+
+#if __HAVE_DISTINCT_FLOAT16 || (__HAVE_FLOAT16 && !defined _LIBC)
+# define _Mdouble_		_Float16
+# define __MATH_PRECNAME(name,r) name##f16##r
+# define __MATH_DECLARING_DOUBLE  0
+# define __MATH_DECLARING_FLOATN  1
+# if __HAVE_DISTINCT_FLOAT16
+#  include <bits/mathcalls-helper-functions.h>
+# endif
+# if __GLIBC_USE (IEC_60559_TYPES_EXT)
+#  include <bits/mathcalls.h>
+# endif
+# undef _Mdouble_
+# undef __MATH_PRECNAME
+# undef __MATH_DECLARING_DOUBLE
+# undef __MATH_DECLARING_FLOATN
+#endif /* __HAVE_DISTINCT_FLOAT16 || (__HAVE_FLOAT16 && !_LIBC).  */
+
+#if __HAVE_DISTINCT_FLOAT32 || (__HAVE_FLOAT32 && !defined _LIBC)
+# define _Mdouble_		_Float32
+# define __MATH_PRECNAME(name,r) name##f32##r
+# define __MATH_DECLARING_DOUBLE  0
+# define __MATH_DECLARING_FLOATN  1
+# if __HAVE_DISTINCT_FLOAT32
+#  include <bits/mathcalls-helper-functions.h>
+# endif
+# if __GLIBC_USE (IEC_60559_TYPES_EXT)
+#  include <bits/mathcalls.h>
+# endif
+# undef _Mdouble_
+# undef __MATH_PRECNAME
+# undef __MATH_DECLARING_DOUBLE
+# undef __MATH_DECLARING_FLOATN
+#endif /* __HAVE_DISTINCT_FLOAT32 || (__HAVE_FLOAT32 && !_LIBC).  */
+
+#if __HAVE_DISTINCT_FLOAT64 || (__HAVE_FLOAT64 && !defined _LIBC)
+# define _Mdouble_		_Float64
+# define __MATH_PRECNAME(name,r) name##f64##r
+# define __MATH_DECLARING_DOUBLE  0
+# define __MATH_DECLARING_FLOATN  1
+# if __HAVE_DISTINCT_FLOAT64
+#  include <bits/mathcalls-helper-functions.h>
+# endif
+# if __GLIBC_USE (IEC_60559_TYPES_EXT)
+#  include <bits/mathcalls.h>
+# endif
+# undef _Mdouble_
+# undef __MATH_PRECNAME
+# undef __MATH_DECLARING_DOUBLE
+# undef __MATH_DECLARING_FLOATN
+#endif /* __HAVE_DISTINCT_FLOAT64 || (__HAVE_FLOAT64 && !_LIBC).  */
+
+#if __HAVE_DISTINCT_FLOAT128 || (__HAVE_FLOAT128 && !defined _LIBC)
+# define _Mdouble_		_Float128
+# define __MATH_PRECNAME(name,r) name##f128##r
+# define __MATH_DECLARING_DOUBLE  0
+# define __MATH_DECLARING_FLOATN  1
+# if __HAVE_DISTINCT_FLOAT128
+#  include <bits/mathcalls-helper-functions.h>
+# endif
+# if __GLIBC_USE (IEC_60559_TYPES_EXT)
+#  include <bits/mathcalls.h>
+# endif
+# undef _Mdouble_
+# undef __MATH_PRECNAME
+# undef __MATH_DECLARING_DOUBLE
+# undef __MATH_DECLARING_FLOATN
+#endif /* __HAVE_DISTINCT_FLOAT128 || (__HAVE_FLOAT128 && !_LIBC).  */
+
+#if __HAVE_DISTINCT_FLOAT32X || (__HAVE_FLOAT32X && !defined _LIBC)
+# define _Mdouble_		_Float32x
+# define __MATH_PRECNAME(name,r) name##f32x##r
+# define __MATH_DECLARING_DOUBLE  0
+# define __MATH_DECLARING_FLOATN  1
+# if __HAVE_DISTINCT_FLOAT32X
+#  include <bits/mathcalls-helper-functions.h>
+# endif
+# if __GLIBC_USE (IEC_60559_TYPES_EXT)
+#  include <bits/mathcalls.h>
+# endif
+# undef _Mdouble_
+# undef __MATH_PRECNAME
+# undef __MATH_DECLARING_DOUBLE
+# undef __MATH_DECLARING_FLOATN
+#endif /* __HAVE_DISTINCT_FLOAT32X || (__HAVE_FLOAT32X && !_LIBC).  */
+
+#if __HAVE_DISTINCT_FLOAT64X || (__HAVE_FLOAT64X && !defined _LIBC)
+# define _Mdouble_		_Float64x
+# define __MATH_PRECNAME(name,r) name##f64x##r
+# define __MATH_DECLARING_DOUBLE  0
+# define __MATH_DECLARING_FLOATN  1
+# if __HAVE_DISTINCT_FLOAT64X
+#  include <bits/mathcalls-helper-functions.h>
+# endif
+# if __GLIBC_USE (IEC_60559_TYPES_EXT)
+#  include <bits/mathcalls.h>
+# endif
+# undef _Mdouble_
+# undef __MATH_PRECNAME
+# undef __MATH_DECLARING_DOUBLE
+# undef __MATH_DECLARING_FLOATN
+#endif /* __HAVE_DISTINCT_FLOAT64X || (__HAVE_FLOAT64X && !_LIBC).  */
+
+#if __HAVE_DISTINCT_FLOAT128X || (__HAVE_FLOAT128X && !defined _LIBC)
+# define _Mdouble_		_Float128x
+# define __MATH_PRECNAME(name,r) name##f128x##r
+# define __MATH_DECLARING_DOUBLE  0
+# define __MATH_DECLARING_FLOATN  1
+# if __HAVE_DISTINCT_FLOAT128X
+#  include <bits/mathcalls-helper-functions.h>
+# endif
+# if __GLIBC_USE (IEC_60559_TYPES_EXT)
+#  include <bits/mathcalls.h>
+# endif
+# undef _Mdouble_
+# undef __MATH_PRECNAME
+# undef __MATH_DECLARING_DOUBLE
+# undef __MATH_DECLARING_FLOATN
+#endif /* __HAVE_DISTINCT_FLOAT128X || (__HAVE_FLOAT128X && !_LIBC).  */
+
+#undef	__MATHDECL_1_IMPL
+#undef	__MATHDECL_1
+#undef	__MATHDECL_ALIAS
+#undef	__MATHDECL
+#undef	__MATHCALL
+
+/* Declare functions returning a narrower type.  */
+#define __MATHCALL_NARROW_ARGS_1 (_Marg_ __x)
+#define __MATHCALL_NARROW_ARGS_2 (_Marg_ __x, _Marg_ __y)
+#define __MATHCALL_NARROW_ARGS_3 (_Marg_ __x, _Marg_ __y, _Marg_ __z)
+#define __MATHCALL_NARROW_NORMAL(func, nargs)			\
+  extern _Mret_ func __MATHCALL_NARROW_ARGS_ ## nargs __THROW
+#define __MATHCALL_NARROW_REDIR(func, redir, nargs)			\
+  extern _Mret_ __REDIRECT_NTH (func, __MATHCALL_NARROW_ARGS_ ## nargs, \
+				redir)
+#define __MATHCALL_NARROW(func, redir, nargs)	\
+  __MATHCALL_NARROW_NORMAL (func, nargs)
+
+#if __GLIBC_USE (IEC_60559_BFP_EXT_C2X)
+
+# define _Mret_ float
+# define _Marg_ double
+# define __MATHCALL_NAME(name) f ## name
+# include <bits/mathcalls-narrow.h>
+# undef _Mret_
+# undef _Marg_
+# undef __MATHCALL_NAME
+
+# define _Mret_ float
+# define _Marg_ long double
+# define __MATHCALL_NAME(name) f ## name ## l
+# ifdef __LDBL_COMPAT
+#  define __MATHCALL_REDIR_NAME(name) f ## name
+#  define __MATHCALL_REDIR_NAME2(name) f ## name
+#  undef __MATHCALL_NARROW
+#  define __MATHCALL_NARROW(func, redir, nargs) \
+  __MATHCALL_NARROW_REDIR (func, redir, nargs)
+# elif __LDOUBLE_REDIRECTS_TO_FLOAT128_ABI == 1
+#  define __MATHCALL_REDIR_NAME(name) __ ## f32 ## name ## ieee128
+#  define __MATHCALL_REDIR_NAME2(name) __ ## f32 ## name ## ieee128
+#  undef __MATHCALL_NARROW
+#  define __MATHCALL_NARROW(func, redir, nargs) \
+  __MATHCALL_NARROW_REDIR (func, redir, nargs)
+# endif
+# include <bits/mathcalls-narrow.h>
+# undef _Mret_
+# undef _Marg_
+# undef __MATHCALL_NAME
+# if defined __LDBL_COMPAT \
+     || __LDOUBLE_REDIRECTS_TO_FLOAT128_ABI == 1
+#  undef __MATHCALL_REDIR_NAME
+#  undef __MATHCALL_REDIR_NAME2
+#  undef __MATHCALL_NARROW
+#  define __MATHCALL_NARROW(func, redir, nargs) \
+  __MATHCALL_NARROW_NORMAL (func, nargs)
+# endif
+
+# define _Mret_ double
+# define _Marg_ long double
+# define __MATHCALL_NAME(name) d ## name ## l
+# ifdef __LDBL_COMPAT
+#  define __MATHCALL_REDIR_NAME(name) __nldbl_d ## name ## l
+#  define __MATHCALL_REDIR_NAME2(name) name
+#  undef __MATHCALL_NARROW
+#  define __MATHCALL_NARROW(func, redir, nargs) \
+  __MATHCALL_NARROW_REDIR (func, redir, nargs)
+# elif __LDOUBLE_REDIRECTS_TO_FLOAT128_ABI == 1
+#  define __MATHCALL_REDIR_NAME(name) __ ## f64 ## name ## ieee128
+#  define __MATHCALL_REDIR_NAME2(name) __ ## f64 ## name ## ieee128
+#  undef __MATHCALL_NARROW
+#  define __MATHCALL_NARROW(func, redir, nargs) \
+  __MATHCALL_NARROW_REDIR (func, redir, nargs)
+# endif
+# include <bits/mathcalls-narrow.h>
+# undef _Mret_
+# undef _Marg_
+# undef __MATHCALL_NAME
+# if defined __LDBL_COMPAT \
+     || __LDOUBLE_REDIRECTS_TO_FLOAT128_ABI == 1
+#  undef __MATHCALL_REDIR_NAME
+#  undef __MATHCALL_REDIR_NAME2
+#  undef __MATHCALL_NARROW
+#  define __MATHCALL_NARROW(func, redir, nargs) \
+  __MATHCALL_NARROW_NORMAL (func, nargs)
+# endif
+
+#endif
+
+#if __GLIBC_USE (IEC_60559_TYPES_EXT)
+
+# if __HAVE_FLOAT16 && __HAVE_FLOAT32
+#  define _Mret_ _Float16
+#  define _Marg_ _Float32
+#  define __MATHCALL_NAME(name) f16 ## name ## f32
+#  include <bits/mathcalls-narrow.h>
+#  undef _Mret_
+#  undef _Marg_
+#  undef __MATHCALL_NAME
+# endif
+
+# if __HAVE_FLOAT16 && __HAVE_FLOAT32X
+#  define _Mret_ _Float16
+#  define _Marg_ _Float32x
+#  define __MATHCALL_NAME(name) f16 ## name ## f32x
+#  include <bits/mathcalls-narrow.h>
+#  undef _Mret_
+#  undef _Marg_
+#  undef __MATHCALL_NAME
+# endif
+
+# if __HAVE_FLOAT16 && __HAVE_FLOAT64
+#  define _Mret_ _Float16
+#  define _Marg_ _Float64
+#  define __MATHCALL_NAME(name) f16 ## name ## f64
+#  include <bits/mathcalls-narrow.h>
+#  undef _Mret_
+#  undef _Marg_
+#  undef __MATHCALL_NAME
+# endif
+
+# if __HAVE_FLOAT16 && __HAVE_FLOAT64X
+#  define _Mret_ _Float16
+#  define _Marg_ _Float64x
+#  define __MATHCALL_NAME(name) f16 ## name ## f64x
+#  include <bits/mathcalls-narrow.h>
+#  undef _Mret_
+#  undef _Marg_
+#  undef __MATHCALL_NAME
+# endif
+
+# if __HAVE_FLOAT16 && __HAVE_FLOAT128
+#  define _Mret_ _Float16
+#  define _Marg_ _Float128
+#  define __MATHCALL_NAME(name) f16 ## name ## f128
+#  include <bits/mathcalls-narrow.h>
+#  undef _Mret_
+#  undef _Marg_
+#  undef __MATHCALL_NAME
+# endif
+
+# if __HAVE_FLOAT16 && __HAVE_FLOAT128X
+#  define _Mret_ _Float16
+#  define _Marg_ _Float128x
+#  define __MATHCALL_NAME(name) f16 ## name ## f128x
+#  include <bits/mathcalls-narrow.h>
+#  undef _Mret_
+#  undef _Marg_
+#  undef __MATHCALL_NAME
+# endif
+
+# if __HAVE_FLOAT32 && __HAVE_FLOAT32X
+#  define _Mret_ _Float32
+#  define _Marg_ _Float32x
+#  define __MATHCALL_NAME(name) f32 ## name ## f32x
+#  include <bits/mathcalls-narrow.h>
+#  undef _Mret_
+#  undef _Marg_
+#  undef __MATHCALL_NAME
+# endif
+
+# if __HAVE_FLOAT32 && __HAVE_FLOAT64
+#  define _Mret_ _Float32
+#  define _Marg_ _Float64
+#  define __MATHCALL_NAME(name) f32 ## name ## f64
+#  include <bits/mathcalls-narrow.h>
+#  undef _Mret_
+#  undef _Marg_
+#  undef __MATHCALL_NAME
+# endif
+
+# if __HAVE_FLOAT32 && __HAVE_FLOAT64X
+#  define _Mret_ _Float32
+#  define _Marg_ _Float64x
+#  define __MATHCALL_NAME(name) f32 ## name ## f64x
+#  include <bits/mathcalls-narrow.h>
+#  undef _Mret_
+#  undef _Marg_
+#  undef __MATHCALL_NAME
+# endif
+
+# if __HAVE_FLOAT32 && __HAVE_FLOAT128
+#  define _Mret_ _Float32
+#  define _Marg_ _Float128
+#  define __MATHCALL_NAME(name) f32 ## name ## f128
+#  include <bits/mathcalls-narrow.h>
+#  undef _Mret_
+#  undef _Marg_
+#  undef __MATHCALL_NAME
+# endif
+
+# if __HAVE_FLOAT32 && __HAVE_FLOAT128X
+#  define _Mret_ _Float32
+#  define _Marg_ _Float128x
+#  define __MATHCALL_NAME(name) f32 ## name ## f128x
+#  include <bits/mathcalls-narrow.h>
+#  undef _Mret_
+#  undef _Marg_
+#  undef __MATHCALL_NAME
+# endif
+
+# if __HAVE_FLOAT32X && __HAVE_FLOAT64
+#  define _Mret_ _Float32x
+#  define _Marg_ _Float64
+#  define __MATHCALL_NAME(name) f32x ## name ## f64
+#  include <bits/mathcalls-narrow.h>
+#  undef _Mret_
+#  undef _Marg_
+#  undef __MATHCALL_NAME
+# endif
+
+# if __HAVE_FLOAT32X && __HAVE_FLOAT64X
+#  define _Mret_ _Float32x
+#  define _Marg_ _Float64x
+#  define __MATHCALL_NAME(name) f32x ## name ## f64x
+#  include <bits/mathcalls-narrow.h>
+#  undef _Mret_
+#  undef _Marg_
+#  undef __MATHCALL_NAME
+# endif
+
+# if __HAVE_FLOAT32X && __HAVE_FLOAT128
+#  define _Mret_ _Float32x
+#  define _Marg_ _Float128
+#  define __MATHCALL_NAME(name) f32x ## name ## f128
+#  include <bits/mathcalls-narrow.h>
+#  undef _Mret_
+#  undef _Marg_
+#  undef __MATHCALL_NAME
+# endif
+
+# if __HAVE_FLOAT32X && __HAVE_FLOAT128X
+#  define _Mret_ _Float32x
+#  define _Marg_ _Float128x
+#  define __MATHCALL_NAME(name) f32x ## name ## f128x
+#  include <bits/mathcalls-narrow.h>
+#  undef _Mret_
+#  undef _Marg_
+#  undef __MATHCALL_NAME
+# endif
+
+# if __HAVE_FLOAT64 && __HAVE_FLOAT64X
+#  define _Mret_ _Float64
+#  define _Marg_ _Float64x
+#  define __MATHCALL_NAME(name) f64 ## name ## f64x
+#  include <bits/mathcalls-narrow.h>
+#  undef _Mret_
+#  undef _Marg_
+#  undef __MATHCALL_NAME
+# endif
+
+# if __HAVE_FLOAT64 && __HAVE_FLOAT128
+#  define _Mret_ _Float64
+#  define _Marg_ _Float128
+#  define __MATHCALL_NAME(name) f64 ## name ## f128
+#  include <bits/mathcalls-narrow.h>
+#  undef _Mret_
+#  undef _Marg_
+#  undef __MATHCALL_NAME
+# endif
+
+# if __HAVE_FLOAT64 && __HAVE_FLOAT128X
+#  define _Mret_ _Float64
+#  define _Marg_ _Float128x
+#  define __MATHCALL_NAME(name) f64 ## name ## f128x
+#  include <bits/mathcalls-narrow.h>
+#  undef _Mret_
+#  undef _Marg_
+#  undef __MATHCALL_NAME
+# endif
+
+# if __HAVE_FLOAT64X && __HAVE_FLOAT128
+#  define _Mret_ _Float64x
+#  define _Marg_ _Float128
+#  define __MATHCALL_NAME(name) f64x ## name ## f128
+#  include <bits/mathcalls-narrow.h>
+#  undef _Mret_
+#  undef _Marg_
+#  undef __MATHCALL_NAME
+# endif
+
+# if __HAVE_FLOAT64X && __HAVE_FLOAT128X
+#  define _Mret_ _Float64x
+#  define _Marg_ _Float128x
+#  define __MATHCALL_NAME(name) f64x ## name ## f128x
+#  include <bits/mathcalls-narrow.h>
+#  undef _Mret_
+#  undef _Marg_
+#  undef __MATHCALL_NAME
+# endif
+
+# if __HAVE_FLOAT128 && __HAVE_FLOAT128X
+#  define _Mret_ _Float128
+#  define _Marg_ _Float128x
+#  define __MATHCALL_NAME(name) f128 ## name ## f128x
+#  include <bits/mathcalls-narrow.h>
+#  undef _Mret_
+#  undef _Marg_
+#  undef __MATHCALL_NAME
+# endif
+
+#endif
+
+#undef __MATHCALL_NARROW_ARGS_1
+#undef __MATHCALL_NARROW_ARGS_2
+#undef __MATHCALL_NARROW_ARGS_3
+#undef __MATHCALL_NARROW_NORMAL
+#undef __MATHCALL_NARROW_REDIR
+#undef __MATHCALL_NARROW
+
+#if defined __USE_MISC || defined __USE_XOPEN
+/* This variable is used by `gamma' and `lgamma'.  */
+extern int signgam;
+#endif
+
+#if (__HAVE_DISTINCT_FLOAT16			\
+     || __HAVE_DISTINCT_FLOAT32			\
+     || __HAVE_DISTINCT_FLOAT64			\
+     || __HAVE_DISTINCT_FLOAT32X		\
+     || __HAVE_DISTINCT_FLOAT64X		\
+     || __HAVE_DISTINCT_FLOAT128X)
+# error "Unsupported _FloatN or _FloatNx types for <math.h>."
+#endif
+
+/* Depending on the type of TG_ARG, call an appropriately suffixed
+   version of FUNC with arguments (including parentheses) ARGS.
+   Suffixed functions may not exist for long double if it has the same
+   format as double, or for other types with the same format as float,
+   double or long double.  The behavior is undefined if the argument
+   does not have a real floating type.  The definition may use a
+   conditional expression, so all suffixed versions of FUNC must
+   return the same type (FUNC may include a cast if necessary rather
+   than being a single identifier).  */
+#ifdef __NO_LONG_DOUBLE_MATH
+# if __HAVE_DISTINCT_FLOAT128
+#  error "Distinct _Float128 without distinct long double not supported."
+# endif
+# define __MATH_TG(TG_ARG, FUNC, ARGS)					\
+  (sizeof (TG_ARG) == sizeof (float) ? FUNC ## f ARGS : FUNC ARGS)
+#elif __HAVE_DISTINCT_FLOAT128
+# if __HAVE_GENERIC_SELECTION
+#  if __HAVE_FLOATN_NOT_TYPEDEF && __HAVE_FLOAT32
+#   define __MATH_TG_F32(FUNC, ARGS) _Float32: FUNC ## f ARGS,
+#  else
+#   define __MATH_TG_F32(FUNC, ARGS)
+#  endif
+#  if __HAVE_FLOATN_NOT_TYPEDEF && __HAVE_FLOAT64X
+#   if __HAVE_FLOAT64X_LONG_DOUBLE
+#    define __MATH_TG_F64X(FUNC, ARGS) _Float64x: FUNC ## l ARGS,
+#   else
+#    define __MATH_TG_F64X(FUNC, ARGS) _Float64x: FUNC ## f128 ARGS,
+#   endif
+#  else
+#   define __MATH_TG_F64X(FUNC, ARGS)
+#  endif
+#  define __MATH_TG(TG_ARG, FUNC, ARGS)	\
+     _Generic ((TG_ARG),			\
+	       float: FUNC ## f ARGS,		\
+	       __MATH_TG_F32 (FUNC, ARGS)	\
+	       default: FUNC ARGS,		\
+	       long double: FUNC ## l ARGS,	\
+	       __MATH_TG_F64X (FUNC, ARGS)	\
+	       _Float128: FUNC ## f128 ARGS)
+# else
+#  if __HAVE_FLOATN_NOT_TYPEDEF
+#   error "Non-typedef _FloatN but no _Generic."
+#  endif
+#  define __MATH_TG(TG_ARG, FUNC, ARGS)					\
+     __builtin_choose_expr						\
+     (__builtin_types_compatible_p (__typeof (TG_ARG), float),		\
+      FUNC ## f ARGS,							\
+      __builtin_choose_expr						\
+      (__builtin_types_compatible_p (__typeof (TG_ARG), double),	\
+       FUNC ARGS,							\
+       __builtin_choose_expr						\
+       (__builtin_types_compatible_p (__typeof (TG_ARG), long double),	\
+	FUNC ## l ARGS,							\
+	FUNC ## f128 ARGS)))
+# endif
+#else
+# define __MATH_TG(TG_ARG, FUNC, ARGS)		\
+  (sizeof (TG_ARG) == sizeof (float)		\
+   ? FUNC ## f ARGS				\
+   : sizeof (TG_ARG) == sizeof (double)		\
+   ? FUNC ARGS					\
+   : FUNC ## l ARGS)
+#endif
+
+/* ISO C99 defines some generic macros which work on any data type.  */
+#ifdef __USE_ISOC99
+
+/* All floating-point numbers can be put in one of these categories.  */
+enum
+  {
+    FP_NAN =
+# define FP_NAN 0
+      FP_NAN,
+    FP_INFINITE =
+# define FP_INFINITE 1
+      FP_INFINITE,
+    FP_ZERO =
+# define FP_ZERO 2
+      FP_ZERO,
+    FP_SUBNORMAL =
+# define FP_SUBNORMAL 3
+      FP_SUBNORMAL,
+    FP_NORMAL =
+# define FP_NORMAL 4
+      FP_NORMAL
+  };
+
+/* GCC bug 66462 means we cannot use the math builtins with -fsignaling-nan,
+   so disable builtins if this is enabled.  When fixed in a newer GCC,
+   the __SUPPORT_SNAN__ check may be skipped for those versions.  */
+
+/* Return number of classification appropriate for X.  */
+# if ((__GNUC_PREREQ (4,4) && !defined __SUPPORT_SNAN__)		      \
+      || __glibc_clang_prereq (2,8))					      \
+     && (!defined __OPTIMIZE_SIZE__ || defined __cplusplus)
+     /* The check for __cplusplus allows the use of the builtin, even
+	when optimization for size is on.  This is provided for
+	libstdc++, only to let its configure test work when it is built
+	with -Os.  No further use of this definition of fpclassify is
+	expected in C++ mode, since libstdc++ provides its own version
+	of fpclassify in cmath (which undefines fpclassify).  */
+#  define fpclassify(x) __builtin_fpclassify (FP_NAN, FP_INFINITE,	      \
+     FP_NORMAL, FP_SUBNORMAL, FP_ZERO, x)
+# else
+#  define fpclassify(x) __MATH_TG ((x), __fpclassify, (x))
+# endif
+
+/* Return nonzero value if sign of X is negative.  */
+# if __GNUC_PREREQ (6,0) || __glibc_clang_prereq (3,3)
+#  define signbit(x) __builtin_signbit (x)
+# elif defined __cplusplus
+  /* In C++ mode, __MATH_TG cannot be used, because it relies on
+     __builtin_types_compatible_p, which is a C-only builtin.
+     The check for __cplusplus allows the use of the builtin instead of
+     __MATH_TG. This is provided for libstdc++, only to let its configure
+     test work. No further use of this definition of signbit is expected
+     in C++ mode, since libstdc++ provides its own version of signbit
+     in cmath (which undefines signbit). */
+#  define signbit(x) __builtin_signbitl (x)
+# elif __GNUC_PREREQ (4,0)
+#  define signbit(x) __MATH_TG ((x), __builtin_signbit, (x))
+# else
+#  define signbit(x) __MATH_TG ((x), __signbit, (x))
+# endif
+
+/* Return nonzero value if X is not +-Inf or NaN.  */
+# if (__GNUC_PREREQ (4,4) && !defined __SUPPORT_SNAN__) \
+     || __glibc_clang_prereq (2,8)
+#  define isfinite(x) __builtin_isfinite (x)
+# else
+#  define isfinite(x) __MATH_TG ((x), __finite, (x))
+# endif
+
+/* Return nonzero value if X is neither zero, subnormal, Inf, nor NaN.  */
+# if (__GNUC_PREREQ (4,4) && !defined __SUPPORT_SNAN__) \
+     || __glibc_clang_prereq (2,8)
+#  define isnormal(x) __builtin_isnormal (x)
+# else
+#  define isnormal(x) (fpclassify (x) == FP_NORMAL)
+# endif
+
+/* Return nonzero value if X is a NaN.  We could use `fpclassify' but
+   we already have this functions `__isnan' and it is faster.  */
+# if (__GNUC_PREREQ (4,4) && !defined __SUPPORT_SNAN__) \
+     || __glibc_clang_prereq (2,8)
+#  define isnan(x) __builtin_isnan (x)
+# else
+#  define isnan(x) __MATH_TG ((x), __isnan, (x))
+# endif
+
+/* Return nonzero value if X is positive or negative infinity.  */
+# if __HAVE_DISTINCT_FLOAT128 && !__GNUC_PREREQ (7,0) \
+     && !defined __SUPPORT_SNAN__ && !defined __cplusplus
+   /* Since __builtin_isinf_sign is broken for float128 before GCC 7.0,
+      use the helper function, __isinff128, with older compilers.  This is
+      only provided for C mode, because in C++ mode, GCC has no support
+      for __builtin_types_compatible_p (and when in C++ mode, this macro is
+      not used anyway, because libstdc++ headers undefine it).  */
+#  define isinf(x) \
+    (__builtin_types_compatible_p (__typeof (x), _Float128) \
+     ? __isinff128 (x) : __builtin_isinf_sign (x))
+# elif (__GNUC_PREREQ (4,4) && !defined __SUPPORT_SNAN__) \
+       || __glibc_clang_prereq (3,7)
+#  define isinf(x) __builtin_isinf_sign (x)
+# else
+#  define isinf(x) __MATH_TG ((x), __isinf, (x))
+# endif
+
+/* Bitmasks for the math_errhandling macro.  */
+# define MATH_ERRNO	1	/* errno set by math functions.  */
+# define MATH_ERREXCEPT	2	/* Exceptions raised by math functions.  */
+
+/* By default all math functions support both errno and exception handling
+   (except for soft floating point implementations which may only support
+   errno handling).  If errno handling is disabled, exceptions are still
+   supported by GLIBC.  Set math_errhandling to 0 with -ffast-math (this is
+   nonconforming but it is more useful than leaving it undefined).  */
+# ifdef __FAST_MATH__
+#  define math_errhandling	0
+# elif defined __NO_MATH_ERRNO__
+#  define math_errhandling	(MATH_ERREXCEPT)
+# else
+#  define math_errhandling	(MATH_ERRNO | MATH_ERREXCEPT)
+# endif
+
+#endif /* Use ISO C99.  */
+
+#if __GLIBC_USE (IEC_60559_BFP_EXT_C2X)
+# include <bits/iscanonical.h>
+
+/* Return nonzero value if X is a signaling NaN.  */
+# ifndef __cplusplus
+#  define issignaling(x) __MATH_TG ((x), __issignaling, (x))
+# else
+   /* In C++ mode, __MATH_TG cannot be used, because it relies on
+      __builtin_types_compatible_p, which is a C-only builtin.  On the
+      other hand, overloading provides the means to distinguish between
+      the floating-point types.  The overloading resolution will match
+      the correct parameter (regardless of type qualifiers (i.e.: const
+      and volatile)).  */
+extern "C++" {
+inline int issignaling (float __val) { return __issignalingf (__val); }
+inline int issignaling (double __val) { return __issignaling (__val); }
+inline int
+issignaling (long double __val)
+{
+#  ifdef __NO_LONG_DOUBLE_MATH
+  return __issignaling (__val);
+#  else
+  return __issignalingl (__val);
+#  endif
+}
+#  if __HAVE_FLOAT128_UNLIKE_LDBL
+/* When using an IEEE 128-bit long double, _Float128 is defined as long double
+   in C++.  */
+inline int issignaling (_Float128 __val) { return __issignalingf128 (__val); }
+#  endif
+} /* extern C++ */
+# endif
+
+/* Return nonzero value if X is subnormal.  */
+# define issubnormal(x) (fpclassify (x) == FP_SUBNORMAL)
+
+/* Return nonzero value if X is zero.  */
+# ifndef __cplusplus
+#  ifdef __SUPPORT_SNAN__
+#   define iszero(x) (fpclassify (x) == FP_ZERO)
+#  else
+#   define iszero(x) (((__typeof (x)) (x)) == 0)
+#  endif
+# else	/* __cplusplus */
+extern "C++" {
+#  ifdef __SUPPORT_SNAN__
+inline int
+iszero (float __val)
+{
+  return __fpclassifyf (__val) == FP_ZERO;
+}
+inline int
+iszero (double __val)
+{
+  return __fpclassify (__val) == FP_ZERO;
+}
+inline int
+iszero (long double __val)
+{
+#   ifdef __NO_LONG_DOUBLE_MATH
+  return __fpclassify (__val) == FP_ZERO;
+#   else
+  return __fpclassifyl (__val) == FP_ZERO;
+#   endif
+}
+#   if __HAVE_FLOAT128_UNLIKE_LDBL
+  /* When using an IEEE 128-bit long double, _Float128 is defined as long double
+     in C++.  */
+inline int
+iszero (_Float128 __val)
+{
+  return __fpclassifyf128 (__val) == FP_ZERO;
+}
+#   endif
+#  else
+template <class __T> inline bool
+iszero (__T __val)
+{
+  return __val == 0;
+}
+#  endif
+} /* extern C++ */
+# endif	/* __cplusplus */
+#endif /* Use IEC_60559_BFP_EXT.  */
+
+#ifdef __USE_XOPEN
+/* X/Open wants another strange constant.  */
+# define MAXFLOAT	3.40282347e+38F
+#endif
+
+
+/* Some useful constants.  */
+#if defined __USE_MISC || defined __USE_XOPEN
+# define M_E		2.7182818284590452354	/* e */
+# define M_LOG2E	1.4426950408889634074	/* log_2 e */
+# define M_LOG10E	0.43429448190325182765	/* log_10 e */
+# define M_LN2		0.69314718055994530942	/* log_e 2 */
+# define M_LN10		2.30258509299404568402	/* log_e 10 */
+# define M_PI		3.14159265358979323846	/* pi */
+# define M_PI_2		1.57079632679489661923	/* pi/2 */
+# define M_PI_4		0.78539816339744830962	/* pi/4 */
+# define M_1_PI		0.31830988618379067154	/* 1/pi */
+# define M_2_PI		0.63661977236758134308	/* 2/pi */
+# define M_2_SQRTPI	1.12837916709551257390	/* 2/sqrt(pi) */
+# define M_SQRT2	1.41421356237309504880	/* sqrt(2) */
+# define M_SQRT1_2	0.70710678118654752440	/* 1/sqrt(2) */
+#endif
+
+/* GNU extension to provide float constants with similar names.  */
+#ifdef __USE_GNU
+# define M_Ef		2.7182818284590452354f	/* e */
+# define M_LOG2Ef	1.4426950408889634074f	/* log_2 e */
+# define M_LOG10Ef	0.43429448190325182765f	/* log_10 e */
+# define M_LN2f		0.69314718055994530942f	/* log_e 2 */
+# define M_LN10f	2.30258509299404568402f	/* log_e 10 */
+# define M_PIf		3.14159265358979323846f	/* pi */
+# define M_PI_2f	1.57079632679489661923f	/* pi/2 */
+# define M_PI_4f	0.78539816339744830962f	/* pi/4 */
+# define M_1_PIf	0.31830988618379067154f	/* 1/pi */
+# define M_2_PIf	0.63661977236758134308f	/* 2/pi */
+# define M_2_SQRTPIf	1.12837916709551257390f	/* 2/sqrt(pi) */
+# define M_SQRT2f	1.41421356237309504880f	/* sqrt(2) */
+# define M_SQRT1_2f	0.70710678118654752440f	/* 1/sqrt(2) */
+#endif
+
+/* The above constants are not adequate for computation using `long double's.
+   Therefore we provide as an extension constants with similar names as a
+   GNU extension.  Provide enough digits for the 128-bit IEEE quad.  */
+#ifdef __USE_GNU
+# define M_El		2.718281828459045235360287471352662498L /* e */
+# define M_LOG2El	1.442695040888963407359924681001892137L /* log_2 e */
+# define M_LOG10El	0.434294481903251827651128918916605082L /* log_10 e */
+# define M_LN2l		0.693147180559945309417232121458176568L /* log_e 2 */
+# define M_LN10l	2.302585092994045684017991454684364208L /* log_e 10 */
+# define M_PIl		3.141592653589793238462643383279502884L /* pi */
+# define M_PI_2l	1.570796326794896619231321691639751442L /* pi/2 */
+# define M_PI_4l	0.785398163397448309615660845819875721L /* pi/4 */
+# define M_1_PIl	0.318309886183790671537767526745028724L /* 1/pi */
+# define M_2_PIl	0.636619772367581343075535053490057448L /* 2/pi */
+# define M_2_SQRTPIl	1.128379167095512573896158903121545172L /* 2/sqrt(pi) */
+# define M_SQRT2l	1.414213562373095048801688724209698079L /* sqrt(2) */
+# define M_SQRT1_2l	0.707106781186547524400844362104849039L /* 1/sqrt(2) */
+#endif
+
+#if __HAVE_FLOAT16 && defined __USE_GNU
+# define M_Ef16		__f16 (2.718281828459045235360287471352662498) /* e */
+# define M_LOG2Ef16	__f16 (1.442695040888963407359924681001892137) /* log_2 e */
+# define M_LOG10Ef16	__f16 (0.434294481903251827651128918916605082) /* log_10 e */
+# define M_LN2f16	__f16 (0.693147180559945309417232121458176568) /* log_e 2 */
+# define M_LN10f16	__f16 (2.302585092994045684017991454684364208) /* log_e 10 */
+# define M_PIf16	__f16 (3.141592653589793238462643383279502884) /* pi */
+# define M_PI_2f16	__f16 (1.570796326794896619231321691639751442) /* pi/2 */
+# define M_PI_4f16	__f16 (0.785398163397448309615660845819875721) /* pi/4 */
+# define M_1_PIf16	__f16 (0.318309886183790671537767526745028724) /* 1/pi */
+# define M_2_PIf16	__f16 (0.636619772367581343075535053490057448) /* 2/pi */
+# define M_2_SQRTPIf16	__f16 (1.128379167095512573896158903121545172) /* 2/sqrt(pi) */
+# define M_SQRT2f16	__f16 (1.414213562373095048801688724209698079) /* sqrt(2) */
+# define M_SQRT1_2f16	__f16 (0.707106781186547524400844362104849039) /* 1/sqrt(2) */
+#endif
+
+#if __HAVE_FLOAT32 && defined __USE_GNU
+# define M_Ef32		__f32 (2.718281828459045235360287471352662498) /* e */
+# define M_LOG2Ef32	__f32 (1.442695040888963407359924681001892137) /* log_2 e */
+# define M_LOG10Ef32	__f32 (0.434294481903251827651128918916605082) /* log_10 e */
+# define M_LN2f32	__f32 (0.693147180559945309417232121458176568) /* log_e 2 */
+# define M_LN10f32	__f32 (2.302585092994045684017991454684364208) /* log_e 10 */
+# define M_PIf32	__f32 (3.141592653589793238462643383279502884) /* pi */
+# define M_PI_2f32	__f32 (1.570796326794896619231321691639751442) /* pi/2 */
+# define M_PI_4f32	__f32 (0.785398163397448309615660845819875721) /* pi/4 */
+# define M_1_PIf32	__f32 (0.318309886183790671537767526745028724) /* 1/pi */
+# define M_2_PIf32	__f32 (0.636619772367581343075535053490057448) /* 2/pi */
+# define M_2_SQRTPIf32	__f32 (1.128379167095512573896158903121545172) /* 2/sqrt(pi) */
+# define M_SQRT2f32	__f32 (1.414213562373095048801688724209698079) /* sqrt(2) */
+# define M_SQRT1_2f32	__f32 (0.707106781186547524400844362104849039) /* 1/sqrt(2) */
+#endif
+
+#if __HAVE_FLOAT64 && defined __USE_GNU
+# define M_Ef64		__f64 (2.718281828459045235360287471352662498) /* e */
+# define M_LOG2Ef64	__f64 (1.442695040888963407359924681001892137) /* log_2 e */
+# define M_LOG10Ef64	__f64 (0.434294481903251827651128918916605082) /* log_10 e */
+# define M_LN2f64	__f64 (0.693147180559945309417232121458176568) /* log_e 2 */
+# define M_LN10f64	__f64 (2.302585092994045684017991454684364208) /* log_e 10 */
+# define M_PIf64	__f64 (3.141592653589793238462643383279502884) /* pi */
+# define M_PI_2f64	__f64 (1.570796326794896619231321691639751442) /* pi/2 */
+# define M_PI_4f64	__f64 (0.785398163397448309615660845819875721) /* pi/4 */
+# define M_1_PIf64	__f64 (0.318309886183790671537767526745028724) /* 1/pi */
+# define M_2_PIf64	__f64 (0.636619772367581343075535053490057448) /* 2/pi */
+# define M_2_SQRTPIf64	__f64 (1.128379167095512573896158903121545172) /* 2/sqrt(pi) */
+# define M_SQRT2f64	__f64 (1.414213562373095048801688724209698079) /* sqrt(2) */
+# define M_SQRT1_2f64	__f64 (0.707106781186547524400844362104849039) /* 1/sqrt(2) */
+#endif
+
+#if __HAVE_FLOAT128 && defined __USE_GNU
+# define M_Ef128	__f128 (2.718281828459045235360287471352662498) /* e */
+# define M_LOG2Ef128	__f128 (1.442695040888963407359924681001892137) /* log_2 e */
+# define M_LOG10Ef128	__f128 (0.434294481903251827651128918916605082) /* log_10 e */
+# define M_LN2f128	__f128 (0.693147180559945309417232121458176568) /* log_e 2 */
+# define M_LN10f128	__f128 (2.302585092994045684017991454684364208) /* log_e 10 */
+# define M_PIf128	__f128 (3.141592653589793238462643383279502884) /* pi */
+# define M_PI_2f128	__f128 (1.570796326794896619231321691639751442) /* pi/2 */
+# define M_PI_4f128	__f128 (0.785398163397448309615660845819875721) /* pi/4 */
+# define M_1_PIf128	__f128 (0.318309886183790671537767526745028724) /* 1/pi */
+# define M_2_PIf128	__f128 (0.636619772367581343075535053490057448) /* 2/pi */
+# define M_2_SQRTPIf128	__f128 (1.128379167095512573896158903121545172) /* 2/sqrt(pi) */
+# define M_SQRT2f128	__f128 (1.414213562373095048801688724209698079) /* sqrt(2) */
+# define M_SQRT1_2f128	__f128 (0.707106781186547524400844362104849039) /* 1/sqrt(2) */
+#endif
+
+#if __HAVE_FLOAT32X && defined __USE_GNU
+# define M_Ef32x	__f32x (2.718281828459045235360287471352662498) /* e */
+# define M_LOG2Ef32x	__f32x (1.442695040888963407359924681001892137) /* log_2 e */
+# define M_LOG10Ef32x	__f32x (0.434294481903251827651128918916605082) /* log_10 e */
+# define M_LN2f32x	__f32x (0.693147180559945309417232121458176568) /* log_e 2 */
+# define M_LN10f32x	__f32x (2.302585092994045684017991454684364208) /* log_e 10 */
+# define M_PIf32x	__f32x (3.141592653589793238462643383279502884) /* pi */
+# define M_PI_2f32x	__f32x (1.570796326794896619231321691639751442) /* pi/2 */
+# define M_PI_4f32x	__f32x (0.785398163397448309615660845819875721) /* pi/4 */
+# define M_1_PIf32x	__f32x (0.318309886183790671537767526745028724) /* 1/pi */
+# define M_2_PIf32x	__f32x (0.636619772367581343075535053490057448) /* 2/pi */
+# define M_2_SQRTPIf32x	__f32x (1.128379167095512573896158903121545172) /* 2/sqrt(pi) */
+# define M_SQRT2f32x	__f32x (1.414213562373095048801688724209698079) /* sqrt(2) */
+# define M_SQRT1_2f32x	__f32x (0.707106781186547524400844362104849039) /* 1/sqrt(2) */
+#endif
+
+#if __HAVE_FLOAT64X && defined __USE_GNU
+# define M_Ef64x	__f64x (2.718281828459045235360287471352662498) /* e */
+# define M_LOG2Ef64x	__f64x (1.442695040888963407359924681001892137) /* log_2 e */
+# define M_LOG10Ef64x	__f64x (0.434294481903251827651128918916605082) /* log_10 e */
+# define M_LN2f64x	__f64x (0.693147180559945309417232121458176568) /* log_e 2 */
+# define M_LN10f64x	__f64x (2.302585092994045684017991454684364208) /* log_e 10 */
+# define M_PIf64x	__f64x (3.141592653589793238462643383279502884) /* pi */
+# define M_PI_2f64x	__f64x (1.570796326794896619231321691639751442) /* pi/2 */
+# define M_PI_4f64x	__f64x (0.785398163397448309615660845819875721) /* pi/4 */
+# define M_1_PIf64x	__f64x (0.318309886183790671537767526745028724) /* 1/pi */
+# define M_2_PIf64x	__f64x (0.636619772367581343075535053490057448) /* 2/pi */
+# define M_2_SQRTPIf64x	__f64x (1.128379167095512573896158903121545172) /* 2/sqrt(pi) */
+# define M_SQRT2f64x	__f64x (1.414213562373095048801688724209698079) /* sqrt(2) */
+# define M_SQRT1_2f64x	__f64x (0.707106781186547524400844362104849039) /* 1/sqrt(2) */
+#endif
+
+#if __HAVE_FLOAT128X && defined __USE_GNU
+# error "M_* values needed for _Float128x"
+#endif
+
+#ifdef __USE_ISOC99
+# if __GNUC_PREREQ (3, 1)
+/* ISO C99 defines some macros to compare number while taking care for
+   unordered numbers.  Many FPUs provide special instructions to support
+   these operations.  Generic support in GCC for these as builtins went
+   in 2.97, but not all cpus added their patterns until 3.1.  Therefore
+   we enable the builtins from 3.1 onwards and use a generic implementation
+   othwerwise.  */
+#  define isgreater(x, y)	__builtin_isgreater(x, y)
+#  define isgreaterequal(x, y)	__builtin_isgreaterequal(x, y)
+#  define isless(x, y)		__builtin_isless(x, y)
+#  define islessequal(x, y)	__builtin_islessequal(x, y)
+#  define islessgreater(x, y)	__builtin_islessgreater(x, y)
+#  define isunordered(x, y)	__builtin_isunordered(x, y)
+# else
+#  define isgreater(x, y) \
+  (__extension__ ({ __typeof__ (x) __x = (x); __typeof__ (y) __y = (y); \
+		    !isunordered (__x, __y) && __x > __y; }))
+#  define isgreaterequal(x, y) \
+  (__extension__ ({ __typeof__ (x) __x = (x); __typeof__ (y) __y = (y); \
+		    !isunordered (__x, __y) && __x >= __y; }))
+#  define isless(x, y) \
+  (__extension__ ({ __typeof__ (x) __x = (x); __typeof__ (y) __y = (y); \
+		    !isunordered (__x, __y) && __x < __y; }))
+#  define islessequal(x, y) \
+  (__extension__ ({ __typeof__ (x) __x = (x); __typeof__ (y) __y = (y); \
+		    !isunordered (__x, __y) && __x <= __y; }))
+#  define islessgreater(x, y) \
+  (__extension__ ({ __typeof__ (x) __x = (x); __typeof__ (y) __y = (y); \
+		    !isunordered (__x, __y) && __x != __y; }))
+/* isunordered must always check both operands first for signaling NaNs.  */
+#  define isunordered(x, y) \
+  (__extension__ ({ __typeof__ (x) __u = (x); __typeof__ (y) __v = (y); \
+		    __u != __v && (__u != __u || __v != __v); }))
+# endif
+#endif
+
+#if __GLIBC_USE (IEC_60559_BFP_EXT_C2X)
+/* An expression whose type has the widest of the evaluation formats
+   of X and Y (which are of floating-point types).  */
+# if __FLT_EVAL_METHOD__ == 2 || __FLT_EVAL_METHOD__ > 64
+#  define __MATH_EVAL_FMT2(x, y) ((x) + (y) + 0.0L)
+# elif __FLT_EVAL_METHOD__ == 1 || __FLT_EVAL_METHOD__ > 32
+#  define __MATH_EVAL_FMT2(x, y) ((x) + (y) + 0.0)
+# elif __FLT_EVAL_METHOD__ == 0 || __FLT_EVAL_METHOD__ == 32
+#  define __MATH_EVAL_FMT2(x, y) ((x) + (y) + 0.0f)
+# else
+#  define __MATH_EVAL_FMT2(x, y) ((x) + (y))
+# endif
+
+/* Return X == Y but raising "invalid" and setting errno if X or Y is
+   a NaN.  */
+# if !defined __cplusplus || (__cplusplus < 201103L && !defined __GNUC__)
+#  define iseqsig(x, y) \
+   __MATH_TG (__MATH_EVAL_FMT2 (x, y), __iseqsig, ((x), (y)))
+# else
+/* In C++ mode, __MATH_TG cannot be used, because it relies on
+   __builtin_types_compatible_p, which is a C-only builtin.  Moreover,
+   the comparison macros from ISO C take two floating-point arguments,
+   which need not have the same type.  Choosing what underlying function
+   to call requires evaluating the formats of the arguments, then
+   selecting which is wider.  The macro __MATH_EVAL_FMT2 provides this
+   information, however, only the type of the macro expansion is
+   relevant (actually evaluating the expression would be incorrect).
+   Thus, the type is used as a template parameter for __iseqsig_type,
+   which calls the appropriate underlying function.  */
+extern "C++" {
+template<typename> struct __iseqsig_type;
+
+template<> struct __iseqsig_type<float>
+{
+  static int __call (float __x, float __y) throw ()
+  {
+    return __iseqsigf (__x, __y);
+  }
+};
+
+template<> struct __iseqsig_type<double>
+{
+  static int __call (double __x, double __y) throw ()
+  {
+    return __iseqsig (__x, __y);
+  }
+};
+
+template<> struct __iseqsig_type<long double>
+{
+  static int __call (long double __x, long double __y) throw ()
+  {
+#  ifndef __NO_LONG_DOUBLE_MATH
+    return __iseqsigl (__x, __y);
+#  else
+    return __iseqsig (__x, __y);
+#  endif
+  }
+};
+
+#  if __HAVE_FLOAT128_UNLIKE_LDBL
+  /* When using an IEEE 128-bit long double, _Float128 is defined as long double
+     in C++.  */
+template<> struct __iseqsig_type<_Float128>
+{
+  static int __call (_Float128 __x, _Float128 __y) throw ()
+  {
+    return __iseqsigf128 (__x, __y);
+  }
+};
+#  endif
+
+template<typename _T1, typename _T2>
+inline int
+iseqsig (_T1 __x, _T2 __y) throw ()
+{
+#  if __cplusplus >= 201103L
+  typedef decltype (__MATH_EVAL_FMT2 (__x, __y)) _T3;
+#  else
+  typedef __typeof (__MATH_EVAL_FMT2 (__x, __y)) _T3;
+#  endif
+  return __iseqsig_type<_T3>::__call (__x, __y);
+}
+
+} /* extern "C++" */
+# endif /* __cplusplus */
+
+#endif
+
+__END_DECLS
+
+
+#endif /* math.h  */
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@pthread.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@pthread.h
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@pthread.h
@@ -0,0 +1,1348 @@
+/* Copyright (C) 2002-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _PTHREAD_H
+#define _PTHREAD_H	1
+
+#include <features.h>
+#include <sched.h>
+#include <time.h>
+
+#include <bits/endian.h>
+#include <bits/pthreadtypes.h>
+#include <bits/setjmp.h>
+#include <bits/wordsize.h>
+#include <bits/types/struct_timespec.h>
+#include <bits/types/__sigset_t.h>
+#include <bits/types/struct___jmp_buf_tag.h>
+#ifdef __USE_MISC
+# include <bits/pthread_stack_min-dynamic.h>
+#endif
+
+/* Detach state.  */
+enum
+{
+  PTHREAD_CREATE_JOINABLE,
+#define PTHREAD_CREATE_JOINABLE	PTHREAD_CREATE_JOINABLE
+  PTHREAD_CREATE_DETACHED
+#define PTHREAD_CREATE_DETACHED	PTHREAD_CREATE_DETACHED
+};
+
+
+/* Mutex types.  */
+enum
+{
+  PTHREAD_MUTEX_TIMED_NP,
+  PTHREAD_MUTEX_RECURSIVE_NP,
+  PTHREAD_MUTEX_ERRORCHECK_NP,
+  PTHREAD_MUTEX_ADAPTIVE_NP
+#if defined __USE_UNIX98 || defined __USE_XOPEN2K8
+  ,
+  PTHREAD_MUTEX_NORMAL = PTHREAD_MUTEX_TIMED_NP,
+  PTHREAD_MUTEX_RECURSIVE = PTHREAD_MUTEX_RECURSIVE_NP,
+  PTHREAD_MUTEX_ERRORCHECK = PTHREAD_MUTEX_ERRORCHECK_NP,
+  PTHREAD_MUTEX_DEFAULT = PTHREAD_MUTEX_NORMAL
+#endif
+#ifdef __USE_GNU
+  /* For compatibility.  */
+  , PTHREAD_MUTEX_FAST_NP = PTHREAD_MUTEX_TIMED_NP
+#endif
+};
+
+
+#ifdef __USE_XOPEN2K
+/* Robust mutex or not flags.  */
+enum
+{
+  PTHREAD_MUTEX_STALLED,
+  PTHREAD_MUTEX_STALLED_NP = PTHREAD_MUTEX_STALLED,
+  PTHREAD_MUTEX_ROBUST,
+  PTHREAD_MUTEX_ROBUST_NP = PTHREAD_MUTEX_ROBUST
+};
+#endif
+
+
+#if defined __USE_POSIX199506 || defined __USE_UNIX98
+/* Mutex protocols.  */
+enum
+{
+  PTHREAD_PRIO_NONE,
+  PTHREAD_PRIO_INHERIT,
+  PTHREAD_PRIO_PROTECT
+};
+#endif
+
+
+#define PTHREAD_MUTEX_INITIALIZER \
+ { {  __PTHREAD_MUTEX_INITIALIZER (PTHREAD_MUTEX_TIMED_NP) } }
+#ifdef __USE_GNU
+# define PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP \
+ { {  __PTHREAD_MUTEX_INITIALIZER (PTHREAD_MUTEX_RECURSIVE_NP) } }
+# define PTHREAD_ERRORCHECK_MUTEX_INITIALIZER_NP \
+ { {  __PTHREAD_MUTEX_INITIALIZER (PTHREAD_MUTEX_ERRORCHECK_NP) } }
+# define PTHREAD_ADAPTIVE_MUTEX_INITIALIZER_NP \
+ { {  __PTHREAD_MUTEX_INITIALIZER (PTHREAD_MUTEX_ADAPTIVE_NP) } }
+#endif
+
+
+/* Read-write lock types.  */
+#if defined __USE_UNIX98 || defined __USE_XOPEN2K
+enum
+{
+  PTHREAD_RWLOCK_PREFER_READER_NP,
+  PTHREAD_RWLOCK_PREFER_WRITER_NP,
+  PTHREAD_RWLOCK_PREFER_WRITER_NONRECURSIVE_NP,
+  PTHREAD_RWLOCK_DEFAULT_NP = PTHREAD_RWLOCK_PREFER_READER_NP
+};
+
+
+/* Read-write lock initializers.  */
+# define PTHREAD_RWLOCK_INITIALIZER \
+  { { __PTHREAD_RWLOCK_INITIALIZER (PTHREAD_RWLOCK_DEFAULT_NP) } }
+# ifdef __USE_GNU
+#  define PTHREAD_RWLOCK_WRITER_NONRECURSIVE_INITIALIZER_NP \
+  { { __PTHREAD_RWLOCK_INITIALIZER (PTHREAD_RWLOCK_PREFER_WRITER_NONRECURSIVE_NP) } }
+# endif
+#endif  /* Unix98 or XOpen2K */
+
+
+/* Scheduler inheritance.  */
+enum
+{
+  PTHREAD_INHERIT_SCHED,
+#define PTHREAD_INHERIT_SCHED   PTHREAD_INHERIT_SCHED
+  PTHREAD_EXPLICIT_SCHED
+#define PTHREAD_EXPLICIT_SCHED  PTHREAD_EXPLICIT_SCHED
+};
+
+
+/* Scope handling.  */
+enum
+{
+  PTHREAD_SCOPE_SYSTEM,
+#define PTHREAD_SCOPE_SYSTEM    PTHREAD_SCOPE_SYSTEM
+  PTHREAD_SCOPE_PROCESS
+#define PTHREAD_SCOPE_PROCESS   PTHREAD_SCOPE_PROCESS
+};
+
+
+/* Process shared or private flag.  */
+enum
+{
+  PTHREAD_PROCESS_PRIVATE,
+#define PTHREAD_PROCESS_PRIVATE PTHREAD_PROCESS_PRIVATE
+  PTHREAD_PROCESS_SHARED
+#define PTHREAD_PROCESS_SHARED  PTHREAD_PROCESS_SHARED
+};
+
+
+
+/* Conditional variable handling.  */
+#define PTHREAD_COND_INITIALIZER { { {0}, {0}, {0, 0}, {0, 0}, 0, 0, {0, 0} } }
+
+
+/* Cleanup buffers */
+struct _pthread_cleanup_buffer
+{
+  void (*__routine) (void *);             /* Function to call.  */
+  void *__arg;                            /* Its argument.  */
+  int __canceltype;                       /* Saved cancellation type. */
+  struct _pthread_cleanup_buffer *__prev; /* Chaining of cleanup functions.  */
+};
+
+/* Cancellation */
+enum
+{
+  PTHREAD_CANCEL_ENABLE,
+#define PTHREAD_CANCEL_ENABLE   PTHREAD_CANCEL_ENABLE
+  PTHREAD_CANCEL_DISABLE
+#define PTHREAD_CANCEL_DISABLE  PTHREAD_CANCEL_DISABLE
+};
+enum
+{
+  PTHREAD_CANCEL_DEFERRED,
+#define PTHREAD_CANCEL_DEFERRED	PTHREAD_CANCEL_DEFERRED
+  PTHREAD_CANCEL_ASYNCHRONOUS
+#define PTHREAD_CANCEL_ASYNCHRONOUS	PTHREAD_CANCEL_ASYNCHRONOUS
+};
+#define PTHREAD_CANCELED ((void *) -1)
+
+
+/* Single execution handling.  */
+#define PTHREAD_ONCE_INIT 0
+
+
+#ifdef __USE_XOPEN2K
+/* Value returned by 'pthread_barrier_wait' for one of the threads after
+   the required number of threads have called this function.
+   -1 is distinct from 0 and all errno constants */
+# define PTHREAD_BARRIER_SERIAL_THREAD -1
+#endif
+
+
+__BEGIN_DECLS
+
+/* Create a new thread, starting with execution of START-ROUTINE
+   getting passed ARG.  Creation attributed come from ATTR.  The new
+   handle is stored in *NEWTHREAD.  */
+extern int pthread_create (pthread_t *__restrict __newthread,
+			   const pthread_attr_t *__restrict __attr,
+			   void *(*__start_routine) (void *),
+			   void *__restrict __arg) __THROWNL __nonnull ((1, 3));
+
+/* Terminate calling thread.
+
+   The registered cleanup handlers are called via exception handling
+   so we cannot mark this function with __THROW.*/
+extern void pthread_exit (void *__retval) __attribute__ ((__noreturn__));
+
+/* Make calling thread wait for termination of the thread TH.  The
+   exit status of the thread is stored in *THREAD_RETURN, if THREAD_RETURN
+   is not NULL.
+
+   This function is a cancellation point and therefore not marked with
+   __THROW.  */
+extern int pthread_join (pthread_t __th, void **__thread_return);
+
+#ifdef __USE_GNU
+/* Check whether thread TH has terminated.  If yes return the status of
+   the thread in *THREAD_RETURN, if THREAD_RETURN is not NULL.  */
+extern int pthread_tryjoin_np (pthread_t __th, void **__thread_return) __THROW;
+
+# ifndef __USE_TIME_BITS64
+/* Make calling thread wait for termination of the thread TH, but only
+   until TIMEOUT.  The exit status of the thread is stored in
+   *THREAD_RETURN, if THREAD_RETURN is not NULL.
+
+   This function is a cancellation point and therefore not marked with
+   __THROW.  */
+extern int pthread_timedjoin_np (pthread_t __th, void **__thread_return,
+				 const struct timespec *__abstime);
+
+/* Make calling thread wait for termination of the thread TH, but only
+   until TIMEOUT measured against the clock specified by CLOCKID.  The
+   exit status of the thread is stored in *THREAD_RETURN, if
+   THREAD_RETURN is not NULL.
+
+   This function is a cancellation point and therefore not marked with
+   __THROW.  */
+extern int pthread_clockjoin_np (pthread_t __th, void **__thread_return,
+                                 clockid_t __clockid,
+				 const struct timespec *__abstime);
+# else
+#  ifdef __REDIRECT
+extern int __REDIRECT (pthread_timedjoin_np,
+                       (pthread_t __th, void **__thread_return,
+                        const struct timespec *__abstime),
+                       __pthread_timedjoin_np64);
+
+extern int __REDIRECT (pthread_clockjoin_np,
+                       (pthread_t __th, void **__thread_return,
+                        clockid_t __clockid,
+                        const struct timespec *__abstime),
+                       __pthread_clockjoin_np64);
+#  else
+#   define pthread_timedjoin_np __pthread_timedjoin_np64
+#   define pthread_clockjoin_np __pthread_clockjoin_np64
+#  endif
+# endif
+#endif
+
+/* Indicate that the thread TH is never to be joined with PTHREAD_JOIN.
+   The resources of TH will therefore be freed immediately when it
+   terminates, instead of waiting for another thread to perform PTHREAD_JOIN
+   on it.  */
+extern int pthread_detach (pthread_t __th) __THROW;
+
+
+/* Obtain the identifier of the current thread.  */
+extern pthread_t pthread_self (void) __THROW __attribute__ ((__const__));
+
+/* Compare two thread identifiers.  */
+extern int pthread_equal (pthread_t __thread1, pthread_t __thread2)
+  __THROW __attribute__ ((__const__));
+
+
+/* Thread attribute handling.  */
+
+/* Initialize thread attribute *ATTR with default attributes
+   (detachstate is PTHREAD_JOINABLE, scheduling policy is SCHED_OTHER,
+    no user-provided stack).  */
+extern int pthread_attr_init (pthread_attr_t *__attr) __THROW __nonnull ((1));
+
+/* Destroy thread attribute *ATTR.  */
+extern int pthread_attr_destroy (pthread_attr_t *__attr)
+     __THROW __nonnull ((1));
+
+/* Get detach state attribute.  */
+extern int pthread_attr_getdetachstate (const pthread_attr_t *__attr,
+					int *__detachstate)
+     __THROW __nonnull ((1, 2));
+
+/* Set detach state attribute.  */
+extern int pthread_attr_setdetachstate (pthread_attr_t *__attr,
+					int __detachstate)
+     __THROW __nonnull ((1));
+
+
+/* Get the size of the guard area created for stack overflow protection.  */
+extern int pthread_attr_getguardsize (const pthread_attr_t *__attr,
+				      size_t *__guardsize)
+     __THROW __nonnull ((1, 2));
+
+/* Set the size of the guard area created for stack overflow protection.  */
+extern int pthread_attr_setguardsize (pthread_attr_t *__attr,
+				      size_t __guardsize)
+     __THROW __nonnull ((1));
+
+
+/* Return in *PARAM the scheduling parameters of *ATTR.  */
+extern int pthread_attr_getschedparam (const pthread_attr_t *__restrict __attr,
+				       struct sched_param *__restrict __param)
+     __THROW __nonnull ((1, 2));
+
+/* Set scheduling parameters (priority, etc) in *ATTR according to PARAM.  */
+extern int pthread_attr_setschedparam (pthread_attr_t *__restrict __attr,
+				       const struct sched_param *__restrict
+				       __param) __THROW __nonnull ((1, 2));
+
+/* Return in *POLICY the scheduling policy of *ATTR.  */
+extern int pthread_attr_getschedpolicy (const pthread_attr_t *__restrict
+					__attr, int *__restrict __policy)
+     __THROW __nonnull ((1, 2));
+
+/* Set scheduling policy in *ATTR according to POLICY.  */
+extern int pthread_attr_setschedpolicy (pthread_attr_t *__attr, int __policy)
+     __THROW __nonnull ((1));
+
+/* Return in *INHERIT the scheduling inheritance mode of *ATTR.  */
+extern int pthread_attr_getinheritsched (const pthread_attr_t *__restrict
+					 __attr, int *__restrict __inherit)
+     __THROW __nonnull ((1, 2));
+
+/* Set scheduling inheritance mode in *ATTR according to INHERIT.  */
+extern int pthread_attr_setinheritsched (pthread_attr_t *__attr,
+					 int __inherit)
+     __THROW __nonnull ((1));
+
+
+/* Return in *SCOPE the scheduling contention scope of *ATTR.  */
+extern int pthread_attr_getscope (const pthread_attr_t *__restrict __attr,
+				  int *__restrict __scope)
+     __THROW __nonnull ((1, 2));
+
+/* Set scheduling contention scope in *ATTR according to SCOPE.  */
+extern int pthread_attr_setscope (pthread_attr_t *__attr, int __scope)
+     __THROW __nonnull ((1));
+
+/* Return the previously set address for the stack.  */
+extern int pthread_attr_getstackaddr (const pthread_attr_t *__restrict
+				      __attr, void **__restrict __stackaddr)
+     __THROW __nonnull ((1, 2)) __attribute_deprecated__;
+
+/* Set the starting address of the stack of the thread to be created.
+   Depending on whether the stack grows up or down the value must either
+   be higher or lower than all the address in the memory block.  The
+   minimal size of the block must be PTHREAD_STACK_MIN.  */
+extern int pthread_attr_setstackaddr (pthread_attr_t *__attr,
+				      void *__stackaddr)
+     __THROW __nonnull ((1)) __attribute_deprecated__;
+
+/* Return the currently used minimal stack size.  */
+extern int pthread_attr_getstacksize (const pthread_attr_t *__restrict
+				      __attr, size_t *__restrict __stacksize)
+     __THROW __nonnull ((1, 2));
+
+/* Add information about the minimum stack size needed for the thread
+   to be started.  This size must never be less than PTHREAD_STACK_MIN
+   and must also not exceed the system limits.  */
+extern int pthread_attr_setstacksize (pthread_attr_t *__attr,
+				      size_t __stacksize)
+     __THROW __nonnull ((1));
+
+#ifdef __USE_XOPEN2K
+/* Return the previously set address for the stack.  */
+extern int pthread_attr_getstack (const pthread_attr_t *__restrict __attr,
+				  void **__restrict __stackaddr,
+				  size_t *__restrict __stacksize)
+     __THROW __nonnull ((1, 2, 3));
+
+/* The following two interfaces are intended to replace the last two.  They
+   require setting the address as well as the size since only setting the
+   address will make the implementation on some architectures impossible.  */
+extern int pthread_attr_setstack (pthread_attr_t *__attr, void *__stackaddr,
+				  size_t __stacksize) __THROW __nonnull ((1));
+#endif
+
+#ifdef __USE_GNU
+/* Thread created with attribute ATTR will be limited to run only on
+   the processors represented in CPUSET.  */
+extern int pthread_attr_setaffinity_np (pthread_attr_t *__attr,
+					size_t __cpusetsize,
+					const cpu_set_t *__cpuset)
+     __THROW __nonnull ((1, 3));
+
+/* Get bit set in CPUSET representing the processors threads created with
+   ATTR can run on.  */
+extern int pthread_attr_getaffinity_np (const pthread_attr_t *__attr,
+					size_t __cpusetsize,
+					cpu_set_t *__cpuset)
+     __THROW __nonnull ((1, 3));
+
+/* Get the default attributes used by pthread_create in this process.  */
+extern int pthread_getattr_default_np (pthread_attr_t *__attr)
+     __THROW __nonnull ((1));
+
+/* Store *SIGMASK as the signal mask for the new thread in *ATTR.  */
+extern int pthread_attr_setsigmask_np (pthread_attr_t *__attr,
+				       const __sigset_t *sigmask);
+
+/* Store the signal mask of *ATTR in *SIGMASK.  If there is no signal
+   mask stored, return PTHREAD_ATTR_NOSIGMASK_NP.  Return zero on
+   success.  */
+extern int pthread_attr_getsigmask_np (const pthread_attr_t *__attr,
+				       __sigset_t *sigmask);
+
+/* Special return value from pthread_attr_getsigmask_np if the signal
+   mask has not been set.  */
+#define PTHREAD_ATTR_NO_SIGMASK_NP (-1)
+
+/* Set the default attributes to be used by pthread_create in this
+   process.  */
+extern int pthread_setattr_default_np (const pthread_attr_t *__attr)
+     __THROW __nonnull ((1));
+
+/* Initialize thread attribute *ATTR with attributes corresponding to the
+   already running thread TH.  It shall be called on uninitialized ATTR
+   and destroyed with pthread_attr_destroy when no longer needed.  */
+extern int pthread_getattr_np (pthread_t __th, pthread_attr_t *__attr)
+     __THROW __nonnull ((2));
+#endif
+
+
+/* Functions for scheduling control.  */
+
+/* Set the scheduling parameters for TARGET_THREAD according to POLICY
+   and *PARAM.  */
+extern int pthread_setschedparam (pthread_t __target_thread, int __policy,
+				  const struct sched_param *__param)
+     __THROW __nonnull ((3));
+
+/* Return in *POLICY and *PARAM the scheduling parameters for TARGET_THREAD. */
+extern int pthread_getschedparam (pthread_t __target_thread,
+				  int *__restrict __policy,
+				  struct sched_param *__restrict __param)
+     __THROW __nonnull ((2, 3));
+
+/* Set the scheduling priority for TARGET_THREAD.  */
+extern int pthread_setschedprio (pthread_t __target_thread, int __prio)
+     __THROW;
+
+
+#ifdef __USE_GNU
+/* Get thread name visible in the kernel and its interfaces.  */
+extern int pthread_getname_np (pthread_t __target_thread, char *__buf,
+			       size_t __buflen)
+     __THROW __nonnull ((2));
+
+/* Set thread name visible in the kernel and its interfaces.  */
+extern int pthread_setname_np (pthread_t __target_thread, const char *__name)
+     __THROW __nonnull ((2));
+#endif
+
+
+#ifdef __USE_UNIX98
+/* Determine level of concurrency.  */
+extern int pthread_getconcurrency (void) __THROW;
+
+/* Set new concurrency level to LEVEL.  */
+extern int pthread_setconcurrency (int __level) __THROW;
+#endif
+
+#ifdef __USE_GNU
+extern int pthread_yield (void) __THROW;
+# ifdef __REDIRECT_NTH
+extern int __REDIRECT_NTH (pthread_yield, (void), sched_yield)
+  __attribute_deprecated_msg__ ("\
+pthread_yield is deprecated, use sched_yield instead");
+# else
+#  define pthread_yield sched_yield
+# endif
+
+
+/* Limit specified thread TH to run only on the processors represented
+   in CPUSET.  */
+extern int pthread_setaffinity_np (pthread_t __th, size_t __cpusetsize,
+				   const cpu_set_t *__cpuset)
+     __THROW __nonnull ((3));
+
+/* Get bit set in CPUSET representing the processors TH can run on.  */
+extern int pthread_getaffinity_np (pthread_t __th, size_t __cpusetsize,
+				   cpu_set_t *__cpuset)
+     __THROW __nonnull ((3));
+#endif
+
+
+/* Functions for handling initialization.  */
+
+/* Guarantee that the initialization function INIT_ROUTINE will be called
+   only once, even if pthread_once is executed several times with the
+   same ONCE_CONTROL argument. ONCE_CONTROL must point to a static or
+   extern variable initialized to PTHREAD_ONCE_INIT.
+
+   The initialization functions might throw exception which is why
+   this function is not marked with __THROW.  */
+extern int pthread_once (pthread_once_t *__once_control,
+			 void (*__init_routine) (void)) __nonnull ((1, 2));
+
+
+/* Functions for handling cancellation.
+
+   Note that these functions are explicitly not marked to not throw an
+   exception in C++ code.  If cancellation is implemented by unwinding
+   this is necessary to have the compiler generate the unwind information.  */
+
+/* Set cancelability state of current thread to STATE, returning old
+   state in *OLDSTATE if OLDSTATE is not NULL.  */
+extern int pthread_setcancelstate (int __state, int *__oldstate);
+
+/* Set cancellation state of current thread to TYPE, returning the old
+   type in *OLDTYPE if OLDTYPE is not NULL.  */
+extern int pthread_setcanceltype (int __type, int *__oldtype);
+
+/* Cancel THREAD immediately or at the next possibility.  */
+extern int pthread_cancel (pthread_t __th);
+
+/* Test for pending cancellation for the current thread and terminate
+   the thread as per pthread_exit(PTHREAD_CANCELED) if it has been
+   cancelled.  */
+extern void pthread_testcancel (void);
+
+
+/* Cancellation handling with integration into exception handling.  */
+
+struct __cancel_jmp_buf_tag
+{
+  __jmp_buf __cancel_jmp_buf;
+  int __mask_was_saved;
+};
+
+typedef struct
+{
+  struct __cancel_jmp_buf_tag __cancel_jmp_buf[1];
+  void *__pad[4];
+} __pthread_unwind_buf_t __attribute__ ((__aligned__));
+
+/* No special attributes by default.  */
+#ifndef __cleanup_fct_attribute
+# define __cleanup_fct_attribute
+#endif
+
+
+/* Structure to hold the cleanup handler information.  */
+struct __pthread_cleanup_frame
+{
+  void (*__cancel_routine) (void *);
+  void *__cancel_arg;
+  int __do_it;
+  int __cancel_type;
+};
+
+#if defined __GNUC__ && defined __EXCEPTIONS
+# ifdef __cplusplus
+/* Class to handle cancellation handler invocation.  */
+class __pthread_cleanup_class
+{
+  void (*__cancel_routine) (void *);
+  void *__cancel_arg;
+  int __do_it;
+  int __cancel_type;
+
+ public:
+  __pthread_cleanup_class (void (*__fct) (void *), void *__arg)
+    : __cancel_routine (__fct), __cancel_arg (__arg), __do_it (1) { }
+  ~__pthread_cleanup_class () { if (__do_it) __cancel_routine (__cancel_arg); }
+  void __setdoit (int __newval) { __do_it = __newval; }
+  void __defer () { pthread_setcanceltype (PTHREAD_CANCEL_DEFERRED,
+					   &__cancel_type); }
+  void __restore () const { pthread_setcanceltype (__cancel_type, 0); }
+};
+
+/* Install a cleanup handler: ROUTINE will be called with arguments ARG
+   when the thread is canceled or calls pthread_exit.  ROUTINE will also
+   be called with arguments ARG when the matching pthread_cleanup_pop
+   is executed with non-zero EXECUTE argument.
+
+   pthread_cleanup_push and pthread_cleanup_pop are macros and must always
+   be used in matching pairs at the same nesting level of braces.  */
+#  define pthread_cleanup_push(routine, arg) \
+  do {									      \
+    __pthread_cleanup_class __clframe (routine, arg)
+
+/* Remove a cleanup handler installed by the matching pthread_cleanup_push.
+   If EXECUTE is non-zero, the handler function is called. */
+#  define pthread_cleanup_pop(execute) \
+    __clframe.__setdoit (execute);					      \
+  } while (0)
+
+#  ifdef __USE_GNU
+/* Install a cleanup handler as pthread_cleanup_push does, but also
+   saves the current cancellation type and sets it to deferred
+   cancellation.  */
+#   define pthread_cleanup_push_defer_np(routine, arg) \
+  do {									      \
+    __pthread_cleanup_class __clframe (routine, arg);			      \
+    __clframe.__defer ()
+
+/* Remove a cleanup handler as pthread_cleanup_pop does, but also
+   restores the cancellation type that was in effect when the matching
+   pthread_cleanup_push_defer was called.  */
+#   define pthread_cleanup_pop_restore_np(execute) \
+    __clframe.__restore ();						      \
+    __clframe.__setdoit (execute);					      \
+  } while (0)
+#  endif
+# else
+/* Function called to call the cleanup handler.  As an extern inline
+   function the compiler is free to decide inlining the change when
+   needed or fall back on the copy which must exist somewhere
+   else.  */
+__extern_inline void
+__pthread_cleanup_routine (struct __pthread_cleanup_frame *__frame)
+{
+  if (__frame->__do_it)
+    __frame->__cancel_routine (__frame->__cancel_arg);
+}
+
+/* Install a cleanup handler: ROUTINE will be called with arguments ARG
+   when the thread is canceled or calls pthread_exit.  ROUTINE will also
+   be called with arguments ARG when the matching pthread_cleanup_pop
+   is executed with non-zero EXECUTE argument.
+
+   pthread_cleanup_push and pthread_cleanup_pop are macros and must always
+   be used in matching pairs at the same nesting level of braces.  */
+#  define pthread_cleanup_push(routine, arg) \
+  do {									      \
+    struct __pthread_cleanup_frame __clframe				      \
+      __attribute__ ((__cleanup__ (__pthread_cleanup_routine)))		      \
+      = { .__cancel_routine = (routine), .__cancel_arg = (arg),	 	      \
+	  .__do_it = 1 };
+
+/* Remove a cleanup handler installed by the matching pthread_cleanup_push.
+   If EXECUTE is non-zero, the handler function is called. */
+#  define pthread_cleanup_pop(execute) \
+    __clframe.__do_it = (execute);					      \
+  } while (0)
+
+#  ifdef __USE_GNU
+/* Install a cleanup handler as pthread_cleanup_push does, but also
+   saves the current cancellation type and sets it to deferred
+   cancellation.  */
+#   define pthread_cleanup_push_defer_np(routine, arg) \
+  do {									      \
+    struct __pthread_cleanup_frame __clframe				      \
+      __attribute__ ((__cleanup__ (__pthread_cleanup_routine)))		      \
+      = { .__cancel_routine = (routine), .__cancel_arg = (arg),		      \
+	  .__do_it = 1 };						      \
+    (void) pthread_setcanceltype (PTHREAD_CANCEL_DEFERRED,		      \
+				  &__clframe.__cancel_type)
+
+/* Remove a cleanup handler as pthread_cleanup_pop does, but also
+   restores the cancellation type that was in effect when the matching
+   pthread_cleanup_push_defer was called.  */
+#   define pthread_cleanup_pop_restore_np(execute) \
+    (void) pthread_setcanceltype (__clframe.__cancel_type, NULL);	      \
+    __clframe.__do_it = (execute);					      \
+  } while (0)
+#  endif
+# endif
+#else
+/* Install a cleanup handler: ROUTINE will be called with arguments ARG
+   when the thread is canceled or calls pthread_exit.  ROUTINE will also
+   be called with arguments ARG when the matching pthread_cleanup_pop
+   is executed with non-zero EXECUTE argument.
+
+   pthread_cleanup_push and pthread_cleanup_pop are macros and must always
+   be used in matching pairs at the same nesting level of braces.  */
+# define pthread_cleanup_push(routine, arg) \
+  do {									      \
+    __pthread_unwind_buf_t __cancel_buf;				      \
+    void (*__cancel_routine) (void *) = (routine);			      \
+    void *__cancel_arg = (arg);						      \
+    int __not_first_call = __sigsetjmp_cancel (__cancel_buf.__cancel_jmp_buf, \
+					       0);			      \
+    if (__glibc_unlikely (__not_first_call))				      \
+      {									      \
+	__cancel_routine (__cancel_arg);				      \
+	__pthread_unwind_next (&__cancel_buf);				      \
+	/* NOTREACHED */						      \
+      }									      \
+									      \
+    __pthread_register_cancel (&__cancel_buf);				      \
+    do {
+extern void __pthread_register_cancel (__pthread_unwind_buf_t *__buf)
+     __cleanup_fct_attribute;
+
+/* Remove a cleanup handler installed by the matching pthread_cleanup_push.
+   If EXECUTE is non-zero, the handler function is called. */
+# define pthread_cleanup_pop(execute) \
+      do { } while (0);/* Empty to allow label before pthread_cleanup_pop.  */\
+    } while (0);							      \
+    __pthread_unregister_cancel (&__cancel_buf);			      \
+    if (execute)							      \
+      __cancel_routine (__cancel_arg);					      \
+  } while (0)
+extern void __pthread_unregister_cancel (__pthread_unwind_buf_t *__buf)
+  __cleanup_fct_attribute;
+
+# ifdef __USE_GNU
+/* Install a cleanup handler as pthread_cleanup_push does, but also
+   saves the current cancellation type and sets it to deferred
+   cancellation.  */
+#  define pthread_cleanup_push_defer_np(routine, arg) \
+  do {									      \
+    __pthread_unwind_buf_t __cancel_buf;				      \
+    void (*__cancel_routine) (void *) = (routine);			      \
+    void *__cancel_arg = (arg);						      \
+    int __not_first_call = __sigsetjmp_cancel (__cancel_buf.__cancel_jmp_buf, \
+					       0);			      \
+    if (__glibc_unlikely (__not_first_call))				      \
+      {									      \
+	__cancel_routine (__cancel_arg);				      \
+	__pthread_unwind_next (&__cancel_buf);				      \
+	/* NOTREACHED */						      \
+      }									      \
+									      \
+    __pthread_register_cancel_defer (&__cancel_buf);			      \
+    do {
+extern void __pthread_register_cancel_defer (__pthread_unwind_buf_t *__buf)
+     __cleanup_fct_attribute;
+
+/* Remove a cleanup handler as pthread_cleanup_pop does, but also
+   restores the cancellation type that was in effect when the matching
+   pthread_cleanup_push_defer was called.  */
+#  define pthread_cleanup_pop_restore_np(execute) \
+      do { } while (0);/* Empty to allow label before pthread_cleanup_pop.  */\
+    } while (0);							      \
+    __pthread_unregister_cancel_restore (&__cancel_buf);		      \
+    if (execute)							      \
+      __cancel_routine (__cancel_arg);					      \
+  } while (0)
+extern void __pthread_unregister_cancel_restore (__pthread_unwind_buf_t *__buf)
+  __cleanup_fct_attribute;
+# endif
+
+/* Internal interface to initiate cleanup.  */
+extern void __pthread_unwind_next (__pthread_unwind_buf_t *__buf)
+     __cleanup_fct_attribute __attribute__ ((__noreturn__))
+# ifndef SHARED
+     __attribute__ ((__weak__))
+# endif
+     ;
+#endif
+
+/* Function used in the macros.  Calling __sigsetjmp, with its first
+   argument declared as an array, results in a -Wstringop-overflow
+   warning from GCC 11 because struct pthread_unwind_buf is smaller
+   than jmp_buf.  The calls from the macros have __SAVEMASK set to 0,
+   so nothing beyond the common prefix is used and this warning is a
+   false positive.  Use an alias with its first argument declared to
+   use the type in the macros if possible to avoid this warning.  */
+#if __GNUC_PREREQ (11, 0)
+extern int __REDIRECT_NTHNL (__sigsetjmp_cancel,
+			     (struct __cancel_jmp_buf_tag __env[1],
+			      int __savemask),
+			     __sigsetjmp) __attribute_returns_twice__;
+#else
+# define __sigsetjmp_cancel(env, savemask) \
+  __sigsetjmp ((struct __jmp_buf_tag *) (void *) (env), (savemask))
+extern int __sigsetjmp (struct __jmp_buf_tag __env[1],
+			int __savemask) __THROWNL;
+#endif
+
+
+/* Mutex handling.  */
+
+/* Initialize a mutex.  */
+extern int pthread_mutex_init (pthread_mutex_t *__mutex,
+			       const pthread_mutexattr_t *__mutexattr)
+     __THROW __nonnull ((1));
+
+/* Destroy a mutex.  */
+extern int pthread_mutex_destroy (pthread_mutex_t *__mutex)
+     __THROW __nonnull ((1));
+
+/* Try locking a mutex.  */
+extern int pthread_mutex_trylock (pthread_mutex_t *__mutex)
+     __THROWNL __nonnull ((1));
+
+/* Lock a mutex.  */
+extern int pthread_mutex_lock (pthread_mutex_t *__mutex)
+     __THROWNL __nonnull ((1));
+
+#ifdef __USE_XOPEN2K
+/* Wait until lock becomes available, or specified time passes. */
+# ifndef __USE_TIME_BITS64
+extern int pthread_mutex_timedlock (pthread_mutex_t *__restrict __mutex,
+				    const struct timespec *__restrict
+				    __abstime) __THROWNL __nonnull ((1, 2));
+# else
+#  ifdef __REDIRECT_NTHNL
+extern int __REDIRECT_NTHNL (pthread_mutex_timedlock,
+                             (pthread_mutex_t *__restrict __mutex,
+                              const struct timespec *__restrict __abstime),
+                             __pthread_mutex_timedlock64) __nonnull ((1, 2));
+#  else
+#   define pthread_mutex_timedlock __pthread_mutex_timedlock64
+#  endif
+# endif
+#endif
+
+#ifdef __USE_GNU
+# ifndef __USE_TIME_BITS64
+extern int pthread_mutex_clocklock (pthread_mutex_t *__restrict __mutex,
+				    clockid_t __clockid,
+				    const struct timespec *__restrict
+				    __abstime) __THROWNL __nonnull ((1, 3));
+# else
+#  ifdef __REDIRECT_NTHNL
+extern int __REDIRECT_NTHNL (pthread_mutex_clocklock,
+                             (pthread_mutex_t *__restrict __mutex,
+                              clockid_t __clockid,
+                              const struct timespec *__restrict __abstime),
+                             __pthread_mutex_clocklock64) __nonnull ((1, 3));
+#  else
+#   define pthread_mutex_clocklock __pthread_mutex_clocklock64
+#  endif
+# endif
+#endif
+
+/* Unlock a mutex.  */
+extern int pthread_mutex_unlock (pthread_mutex_t *__mutex)
+     __THROWNL __nonnull ((1));
+
+
+/* Get the priority ceiling of MUTEX.  */
+extern int pthread_mutex_getprioceiling (const pthread_mutex_t *
+					 __restrict __mutex,
+					 int *__restrict __prioceiling)
+     __THROW __nonnull ((1, 2));
+
+/* Set the priority ceiling of MUTEX to PRIOCEILING, return old
+   priority ceiling value in *OLD_CEILING.  */
+extern int pthread_mutex_setprioceiling (pthread_mutex_t *__restrict __mutex,
+					 int __prioceiling,
+					 int *__restrict __old_ceiling)
+     __THROW __nonnull ((1, 3));
+
+
+#ifdef __USE_XOPEN2K8
+/* Declare the state protected by MUTEX as consistent.  */
+extern int pthread_mutex_consistent (pthread_mutex_t *__mutex)
+     __THROW __nonnull ((1));
+# ifdef __USE_GNU
+#  ifdef __REDIRECT_NTH
+extern int __REDIRECT_NTH (pthread_mutex_consistent_np, (pthread_mutex_t *),
+			   pthread_mutex_consistent) __nonnull ((1))
+  __attribute_deprecated_msg__ ("\
+pthread_mutex_consistent_np is deprecated, use pthread_mutex_consistent");
+#  else
+#   define pthread_mutex_consistent_np pthread_mutex_consistent
+#  endif
+# endif
+#endif
+
+
+/* Functions for handling mutex attributes.  */
+
+/* Initialize mutex attribute object ATTR with default attributes
+   (kind is PTHREAD_MUTEX_TIMED_NP).  */
+extern int pthread_mutexattr_init (pthread_mutexattr_t *__attr)
+     __THROW __nonnull ((1));
+
+/* Destroy mutex attribute object ATTR.  */
+extern int pthread_mutexattr_destroy (pthread_mutexattr_t *__attr)
+     __THROW __nonnull ((1));
+
+/* Get the process-shared flag of the mutex attribute ATTR.  */
+extern int pthread_mutexattr_getpshared (const pthread_mutexattr_t *
+					 __restrict __attr,
+					 int *__restrict __pshared)
+     __THROW __nonnull ((1, 2));
+
+/* Set the process-shared flag of the mutex attribute ATTR.  */
+extern int pthread_mutexattr_setpshared (pthread_mutexattr_t *__attr,
+					 int __pshared)
+     __THROW __nonnull ((1));
+
+#if defined __USE_UNIX98 || defined __USE_XOPEN2K8
+/* Return in *KIND the mutex kind attribute in *ATTR.  */
+extern int pthread_mutexattr_gettype (const pthread_mutexattr_t *__restrict
+				      __attr, int *__restrict __kind)
+     __THROW __nonnull ((1, 2));
+
+/* Set the mutex kind attribute in *ATTR to KIND (either PTHREAD_MUTEX_NORMAL,
+   PTHREAD_MUTEX_RECURSIVE, PTHREAD_MUTEX_ERRORCHECK, or
+   PTHREAD_MUTEX_DEFAULT).  */
+extern int pthread_mutexattr_settype (pthread_mutexattr_t *__attr, int __kind)
+     __THROW __nonnull ((1));
+#endif
+
+/* Return in *PROTOCOL the mutex protocol attribute in *ATTR.  */
+extern int pthread_mutexattr_getprotocol (const pthread_mutexattr_t *
+					  __restrict __attr,
+					  int *__restrict __protocol)
+     __THROW __nonnull ((1, 2));
+
+/* Set the mutex protocol attribute in *ATTR to PROTOCOL (either
+   PTHREAD_PRIO_NONE, PTHREAD_PRIO_INHERIT, or PTHREAD_PRIO_PROTECT).  */
+extern int pthread_mutexattr_setprotocol (pthread_mutexattr_t *__attr,
+					  int __protocol)
+     __THROW __nonnull ((1));
+
+/* Return in *PRIOCEILING the mutex prioceiling attribute in *ATTR.  */
+extern int pthread_mutexattr_getprioceiling (const pthread_mutexattr_t *
+					     __restrict __attr,
+					     int *__restrict __prioceiling)
+     __THROW __nonnull ((1, 2));
+
+/* Set the mutex prioceiling attribute in *ATTR to PRIOCEILING.  */
+extern int pthread_mutexattr_setprioceiling (pthread_mutexattr_t *__attr,
+					     int __prioceiling)
+     __THROW __nonnull ((1));
+
+#ifdef __USE_XOPEN2K
+/* Get the robustness flag of the mutex attribute ATTR.  */
+extern int pthread_mutexattr_getrobust (const pthread_mutexattr_t *__attr,
+					int *__robustness)
+     __THROW __nonnull ((1, 2));
+# ifdef __USE_GNU
+#  ifdef __REDIRECT_NTH
+extern int __REDIRECT_NTH (pthread_mutexattr_getrobust_np,
+			   (pthread_mutexattr_t *, int *),
+			   pthread_mutexattr_getrobust) __nonnull ((1))
+  __attribute_deprecated_msg__ ("\
+pthread_mutexattr_getrobust_np is deprecated, use pthread_mutexattr_getrobust");
+#  else
+#   define pthread_mutexattr_getrobust_np pthread_mutexattr_getrobust
+#  endif
+# endif
+
+/* Set the robustness flag of the mutex attribute ATTR.  */
+extern int pthread_mutexattr_setrobust (pthread_mutexattr_t *__attr,
+					int __robustness)
+     __THROW __nonnull ((1));
+# ifdef __USE_GNU
+#  ifdef __REDIRECT_NTH
+extern int __REDIRECT_NTH (pthread_mutexattr_setrobust_np,
+			   (pthread_mutexattr_t *, int),
+			   pthread_mutexattr_setrobust) __nonnull ((1))
+  __attribute_deprecated_msg__ ("\
+pthread_mutexattr_setrobust_np is deprecated, use pthread_mutexattr_setrobust");
+#  else
+#   define pthread_mutexattr_setrobust_np pthread_mutexattr_setrobust
+#  endif
+# endif
+#endif
+
+#if defined __USE_UNIX98 || defined __USE_XOPEN2K
+/* Functions for handling read-write locks.  */
+
+/* Initialize read-write lock RWLOCK using attributes ATTR, or use
+   the default values if later is NULL.  */
+extern int pthread_rwlock_init (pthread_rwlock_t *__restrict __rwlock,
+				const pthread_rwlockattr_t *__restrict
+				__attr) __THROW __nonnull ((1));
+
+/* Destroy read-write lock RWLOCK.  */
+extern int pthread_rwlock_destroy (pthread_rwlock_t *__rwlock)
+     __THROW __nonnull ((1));
+
+/* Acquire read lock for RWLOCK.  */
+extern int pthread_rwlock_rdlock (pthread_rwlock_t *__rwlock)
+     __THROWNL __nonnull ((1));
+
+/* Try to acquire read lock for RWLOCK.  */
+extern int pthread_rwlock_tryrdlock (pthread_rwlock_t *__rwlock)
+  __THROWNL __nonnull ((1));
+
+# ifdef __USE_XOPEN2K
+/* Try to acquire read lock for RWLOCK or return after specfied time.  */
+#  ifndef __USE_TIME_BITS64
+extern int pthread_rwlock_timedrdlock (pthread_rwlock_t *__restrict __rwlock,
+				       const struct timespec *__restrict
+				       __abstime) __THROWNL __nonnull ((1, 2));
+#  else
+#   ifdef __REDIRECT_NTHNL
+extern int __REDIRECT_NTHNL (pthread_rwlock_timedrdlock,
+                             (pthread_rwlock_t *__restrict __rwlock,
+                              const struct timespec *__restrict __abstime),
+                             __pthread_rwlock_timedrdlock64)
+    __nonnull ((1, 2));
+#   else
+#    define pthread_rwlock_timedrdlock __pthread_rwlock_timedrdlock64
+#   endif
+#  endif
+# endif
+
+# ifdef __USE_GNU
+#  ifndef __USE_TIME_BITS64
+extern int pthread_rwlock_clockrdlock (pthread_rwlock_t *__restrict __rwlock,
+				       clockid_t __clockid,
+				       const struct timespec *__restrict
+				       __abstime) __THROWNL __nonnull ((1, 3));
+#  else
+#   ifdef __REDIRECT_NTHNL
+extern int __REDIRECT_NTHNL (pthread_rwlock_clockrdlock,
+                             (pthread_rwlock_t *__restrict __rwlock,
+                              clockid_t __clockid,
+                              const struct timespec *__restrict __abstime),
+                             __pthread_rwlock_clockrdlock64)
+    __nonnull ((1, 3));
+#   else
+#    define pthread_rwlock_clockrdlock __pthread_rwlock_clockrdlock64
+#   endif
+#  endif
+# endif
+
+/* Acquire write lock for RWLOCK.  */
+extern int pthread_rwlock_wrlock (pthread_rwlock_t *__rwlock)
+     __THROWNL __nonnull ((1));
+
+/* Try to acquire write lock for RWLOCK.  */
+extern int pthread_rwlock_trywrlock (pthread_rwlock_t *__rwlock)
+     __THROWNL __nonnull ((1));
+
+# ifdef __USE_XOPEN2K
+/* Try to acquire write lock for RWLOCK or return after specfied time.  */
+#  ifndef __USE_TIME_BITS64
+extern int pthread_rwlock_timedwrlock (pthread_rwlock_t *__restrict __rwlock,
+				       const struct timespec *__restrict
+				       __abstime) __THROWNL __nonnull ((1, 2));
+#  else
+#   ifdef __REDIRECT_NTHNL
+extern int __REDIRECT_NTHNL (pthread_rwlock_timedwrlock,
+                             (pthread_rwlock_t *__restrict __rwlock,
+                              const struct timespec *__restrict __abstime),
+                             __pthread_rwlock_timedwrlock64)
+    __nonnull ((1, 2));
+#   else
+#    define pthread_rwlock_timedwrlock __pthread_rwlock_timedwrlock64
+#   endif
+#  endif
+# endif
+
+# ifdef __USE_GNU
+#  ifndef __USE_TIME_BITS64
+extern int pthread_rwlock_clockwrlock (pthread_rwlock_t *__restrict __rwlock,
+				       clockid_t __clockid,
+				       const struct timespec *__restrict
+				       __abstime) __THROWNL __nonnull ((1, 3));
+
+#  else
+#   ifdef __REDIRECT_NTHNL
+extern int __REDIRECT_NTHNL (pthread_rwlock_clockwrlock,
+                             (pthread_rwlock_t *__restrict __rwlock,
+                              clockid_t __clockid,
+                              const struct timespec *__restrict __abstime),
+                             __pthread_rwlock_clockwrlock64)
+    __nonnull ((1, 3));
+#   else
+#    define pthread_rwlock_clockwrlock __pthread_rwlock_clockwrlock64
+#   endif
+#  endif
+# endif
+
+/* Unlock RWLOCK.  */
+extern int pthread_rwlock_unlock (pthread_rwlock_t *__rwlock)
+     __THROWNL __nonnull ((1));
+
+
+/* Functions for handling read-write lock attributes.  */
+
+/* Initialize attribute object ATTR with default values.  */
+extern int pthread_rwlockattr_init (pthread_rwlockattr_t *__attr)
+     __THROW __nonnull ((1));
+
+/* Destroy attribute object ATTR.  */
+extern int pthread_rwlockattr_destroy (pthread_rwlockattr_t *__attr)
+     __THROW __nonnull ((1));
+
+/* Return current setting of process-shared attribute of ATTR in PSHARED.  */
+extern int pthread_rwlockattr_getpshared (const pthread_rwlockattr_t *
+					  __restrict __attr,
+					  int *__restrict __pshared)
+     __THROW __nonnull ((1, 2));
+
+/* Set process-shared attribute of ATTR to PSHARED.  */
+extern int pthread_rwlockattr_setpshared (pthread_rwlockattr_t *__attr,
+					  int __pshared)
+     __THROW __nonnull ((1));
+
+/* Return current setting of reader/writer preference.  */
+extern int pthread_rwlockattr_getkind_np (const pthread_rwlockattr_t *
+					  __restrict __attr,
+					  int *__restrict __pref)
+     __THROW __nonnull ((1, 2));
+
+/* Set reader/write preference.  */
+extern int pthread_rwlockattr_setkind_np (pthread_rwlockattr_t *__attr,
+					  int __pref) __THROW __nonnull ((1));
+#endif
+
+
+/* Functions for handling conditional variables.  */
+
+/* Initialize condition variable COND using attributes ATTR, or use
+   the default values if later is NULL.  */
+extern int pthread_cond_init (pthread_cond_t *__restrict __cond,
+			      const pthread_condattr_t *__restrict __cond_attr)
+     __THROW __nonnull ((1));
+
+/* Destroy condition variable COND.  */
+extern int pthread_cond_destroy (pthread_cond_t *__cond)
+     __THROW __nonnull ((1));
+
+/* Wake up one thread waiting for condition variable COND.  */
+extern int pthread_cond_signal (pthread_cond_t *__cond)
+     __THROWNL __nonnull ((1));
+
+/* Wake up all threads waiting for condition variables COND.  */
+extern int pthread_cond_broadcast (pthread_cond_t *__cond)
+     __THROWNL __nonnull ((1));
+
+/* Wait for condition variable COND to be signaled or broadcast.
+   MUTEX is assumed to be locked before.
+
+   This function is a cancellation point and therefore not marked with
+   __THROW.  */
+extern int pthread_cond_wait (pthread_cond_t *__restrict __cond,
+			      pthread_mutex_t *__restrict __mutex)
+     __nonnull ((1, 2));
+
+/* Wait for condition variable COND to be signaled or broadcast until
+   ABSTIME.  MUTEX is assumed to be locked before.  ABSTIME is an
+   absolute time specification; zero is the beginning of the epoch
+   (00:00:00 GMT, January 1, 1970).
+
+   This function is a cancellation point and therefore not marked with
+   __THROW.  */
+# ifndef __USE_TIME_BITS64
+extern int pthread_cond_timedwait (pthread_cond_t *__restrict __cond,
+				   pthread_mutex_t *__restrict __mutex,
+				   const struct timespec *__restrict __abstime)
+     __nonnull ((1, 2, 3));
+# else
+#  ifdef __REDIRECT
+extern int __REDIRECT (pthread_cond_timedwait,
+                       (pthread_cond_t *__restrict __cond,
+                        pthread_mutex_t *__restrict __mutex,
+                        const struct timespec *__restrict __abstime),
+                       __pthread_cond_timedwait64)
+     __nonnull ((1, 2, 3));
+#  else
+#   define pthread_cond_timedwait __pthread_cond_timedwait64
+#  endif
+# endif
+
+# ifdef __USE_GNU
+/* Wait for condition variable COND to be signaled or broadcast until
+   ABSTIME measured by the specified clock. MUTEX is assumed to be
+   locked before. CLOCK is the clock to use. ABSTIME is an absolute
+   time specification against CLOCK's epoch.
+
+   This function is a cancellation point and therefore not marked with
+   __THROW. */
+#  ifndef __USE_TIME_BITS64
+extern int pthread_cond_clockwait (pthread_cond_t *__restrict __cond,
+				   pthread_mutex_t *__restrict __mutex,
+				   __clockid_t __clock_id,
+				   const struct timespec *__restrict __abstime)
+     __nonnull ((1, 2, 4));
+#  else
+#   ifdef __REDIRECT
+extern int __REDIRECT (pthread_cond_clockwait,
+                       (pthread_cond_t *__restrict __cond,
+                        pthread_mutex_t *__restrict __mutex,
+                        __clockid_t __clock_id,
+                        const struct timespec *__restrict __abstime),
+                       __pthread_cond_clockwait64)
+     __nonnull ((1, 2, 4));
+#   else
+#    define pthread_cond_clockwait __pthread_cond_clockwait64
+#   endif
+#  endif
+# endif
+
+/* Functions for handling condition variable attributes.  */
+
+/* Initialize condition variable attribute ATTR.  */
+extern int pthread_condattr_init (pthread_condattr_t *__attr)
+     __THROW __nonnull ((1));
+
+/* Destroy condition variable attribute ATTR.  */
+extern int pthread_condattr_destroy (pthread_condattr_t *__attr)
+     __THROW __nonnull ((1));
+
+/* Get the process-shared flag of the condition variable attribute ATTR.  */
+extern int pthread_condattr_getpshared (const pthread_condattr_t *
+					__restrict __attr,
+					int *__restrict __pshared)
+     __THROW __nonnull ((1, 2));
+
+/* Set the process-shared flag of the condition variable attribute ATTR.  */
+extern int pthread_condattr_setpshared (pthread_condattr_t *__attr,
+					int __pshared) __THROW __nonnull ((1));
+
+#ifdef __USE_XOPEN2K
+/* Get the clock selected for the condition variable attribute ATTR.  */
+extern int pthread_condattr_getclock (const pthread_condattr_t *
+				      __restrict __attr,
+				      __clockid_t *__restrict __clock_id)
+     __THROW __nonnull ((1, 2));
+
+/* Set the clock selected for the condition variable attribute ATTR.  */
+extern int pthread_condattr_setclock (pthread_condattr_t *__attr,
+				      __clockid_t __clock_id)
+     __THROW __nonnull ((1));
+#endif
+
+
+#ifdef __USE_XOPEN2K
+/* Functions to handle spinlocks.  */
+
+/* Initialize the spinlock LOCK.  If PSHARED is nonzero the spinlock can
+   be shared between different processes.  */
+extern int pthread_spin_init (pthread_spinlock_t *__lock, int __pshared)
+     __THROW __nonnull ((1));
+
+/* Destroy the spinlock LOCK.  */
+extern int pthread_spin_destroy (pthread_spinlock_t *__lock)
+     __THROW __nonnull ((1));
+
+/* Wait until spinlock LOCK is retrieved.  */
+extern int pthread_spin_lock (pthread_spinlock_t *__lock)
+     __THROWNL __nonnull ((1));
+
+/* Try to lock spinlock LOCK.  */
+extern int pthread_spin_trylock (pthread_spinlock_t *__lock)
+     __THROWNL __nonnull ((1));
+
+/* Release spinlock LOCK.  */
+extern int pthread_spin_unlock (pthread_spinlock_t *__lock)
+     __THROWNL __nonnull ((1));
+
+
+/* Functions to handle barriers.  */
+
+/* Initialize BARRIER with the attributes in ATTR.  The barrier is
+   opened when COUNT waiters arrived.  */
+extern int pthread_barrier_init (pthread_barrier_t *__restrict __barrier,
+				 const pthread_barrierattr_t *__restrict
+				 __attr, unsigned int __count)
+     __THROW __nonnull ((1));
+
+/* Destroy a previously dynamically initialized barrier BARRIER.  */
+extern int pthread_barrier_destroy (pthread_barrier_t *__barrier)
+     __THROW __nonnull ((1));
+
+/* Wait on barrier BARRIER.  */
+extern int pthread_barrier_wait (pthread_barrier_t *__barrier)
+     __THROWNL __nonnull ((1));
+
+
+/* Initialize barrier attribute ATTR.  */
+extern int pthread_barrierattr_init (pthread_barrierattr_t *__attr)
+     __THROW __nonnull ((1));
+
+/* Destroy previously dynamically initialized barrier attribute ATTR.  */
+extern int pthread_barrierattr_destroy (pthread_barrierattr_t *__attr)
+     __THROW __nonnull ((1));
+
+/* Get the process-shared flag of the barrier attribute ATTR.  */
+extern int pthread_barrierattr_getpshared (const pthread_barrierattr_t *
+					   __restrict __attr,
+					   int *__restrict __pshared)
+     __THROW __nonnull ((1, 2));
+
+/* Set the process-shared flag of the barrier attribute ATTR.  */
+extern int pthread_barrierattr_setpshared (pthread_barrierattr_t *__attr,
+					   int __pshared)
+     __THROW __nonnull ((1));
+#endif
+
+
+/* Functions for handling thread-specific data.  */
+
+/* Create a key value identifying a location in the thread-specific
+   data area.  Each thread maintains a distinct thread-specific data
+   area.  DESTR_FUNCTION, if non-NULL, is called with the value
+   associated to that key when the key is destroyed.
+   DESTR_FUNCTION is not called if the value associated is NULL when
+   the key is destroyed.  */
+extern int pthread_key_create (pthread_key_t *__key,
+			       void (*__destr_function) (void *))
+     __THROW __nonnull ((1));
+
+/* Destroy KEY.  */
+extern int pthread_key_delete (pthread_key_t __key) __THROW;
+
+/* Return current value of the thread-specific data slot identified by KEY.  */
+extern void *pthread_getspecific (pthread_key_t __key) __THROW;
+
+/* Store POINTER in the thread-specific data slot identified by KEY. */
+extern int pthread_setspecific (pthread_key_t __key,
+				const void *__pointer)
+  __THROW __attr_access_none (2);
+
+
+#ifdef __USE_XOPEN2K
+/* Get ID of CPU-time clock for thread THREAD_ID.  */
+extern int pthread_getcpuclockid (pthread_t __thread_id,
+				  __clockid_t *__clock_id)
+     __THROW __nonnull ((2));
+#endif
+
+
+/* Install handlers to be called when a new process is created with FORK.
+   The PREPARE handler is called in the parent process just before performing
+   FORK. The PARENT handler is called in the parent process just after FORK.
+   The CHILD handler is called in the child process.  Each of the three
+   handlers can be NULL, meaning that no handler needs to be called at that
+   point.
+   PTHREAD_ATFORK can be called several times, in which case the PREPARE
+   handlers are called in LIFO order (last added with PTHREAD_ATFORK,
+   first called before FORK), and the PARENT and CHILD handlers are called
+   in FIFO (first added, first called).  */
+
+extern int pthread_atfork (void (*__prepare) (void),
+			   void (*__parent) (void),
+			   void (*__child) (void)) __THROW;
+
+
+#ifdef __USE_EXTERN_INLINES
+/* Optimizations.  */
+__extern_inline int
+__NTH (pthread_equal (pthread_t __thread1, pthread_t __thread2))
+{
+  return __thread1 == __thread2;
+}
+#endif
+
+__END_DECLS
+
+#endif	/* pthread.h */
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@sched.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@sched.h
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@@ -0,0 +1,140 @@
+/* Definitions for POSIX 1003.1b-1993 (aka POSIX.4) scheduling interface.
+   Copyright (C) 1996-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef	_SCHED_H
+#define	_SCHED_H	1
+
+#include <features.h>
+
+/* Get type definitions.  */
+#include <bits/types.h>
+
+#define __need_size_t
+#define __need_NULL
+#include <stddef.h>
+
+#include <bits/types/time_t.h>
+#include <bits/types/struct_timespec.h>
+#ifndef __USE_XOPEN2K
+# include <time.h>
+#endif
+
+#ifndef __pid_t_defined
+typedef __pid_t pid_t;
+# define __pid_t_defined
+#endif
+
+/* Get system specific constant and data structure definitions.  */
+#include <bits/sched.h>
+#include <bits/cpu-set.h>
+
+/* Backward compatibility.  */
+#define sched_priority    sched_priority
+#define __sched_priority  sched_priority
+
+
+__BEGIN_DECLS
+
+/* Set scheduling parameters for a process.  */
+extern int sched_setparam (__pid_t __pid, const struct sched_param *__param)
+     __THROW;
+
+/* Retrieve scheduling parameters for a particular process.  */
+extern int sched_getparam (__pid_t __pid, struct sched_param *__param) __THROW;
+
+/* Set scheduling algorithm and/or parameters for a process.  */
+extern int sched_setscheduler (__pid_t __pid, int __policy,
+			       const struct sched_param *__param) __THROW;
+
+/* Retrieve scheduling algorithm for a particular purpose.  */
+extern int sched_getscheduler (__pid_t __pid) __THROW;
+
+/* Yield the processor.  */
+extern int sched_yield (void) __THROW;
+
+/* Get maximum priority value for a scheduler.  */
+extern int sched_get_priority_max (int __algorithm) __THROW;
+
+/* Get minimum priority value for a scheduler.  */
+extern int sched_get_priority_min (int __algorithm) __THROW;
+
+/* Get the SCHED_RR interval for the named process.  */
+#ifndef __USE_TIME_BITS64
+extern int sched_rr_get_interval (__pid_t __pid, struct timespec *__t) __THROW;
+#else
+# ifdef __REDIRECT_NTH
+extern int __REDIRECT_NTH (sched_rr_get_interval,
+                           (__pid_t __pid, struct timespec *__t),
+                           __sched_rr_get_interval64);
+# else
+#  define sched_rr_get_interval __sched_rr_get_interval64
+# endif
+#endif
+
+#ifdef __USE_GNU
+/* Access macros for `cpu_set'.  */
+# define CPU_SETSIZE __CPU_SETSIZE
+# define CPU_SET(cpu, cpusetp)	 __CPU_SET_S (cpu, sizeof (cpu_set_t), cpusetp)
+# define CPU_CLR(cpu, cpusetp)	 __CPU_CLR_S (cpu, sizeof (cpu_set_t), cpusetp)
+# define CPU_ISSET(cpu, cpusetp) __CPU_ISSET_S (cpu, sizeof (cpu_set_t), \
+						cpusetp)
+# define CPU_ZERO(cpusetp)	 __CPU_ZERO_S (sizeof (cpu_set_t), cpusetp)
+# define CPU_COUNT(cpusetp)	 __CPU_COUNT_S (sizeof (cpu_set_t), cpusetp)
+
+# define CPU_SET_S(cpu, setsize, cpusetp)   __CPU_SET_S (cpu, setsize, cpusetp)
+# define CPU_CLR_S(cpu, setsize, cpusetp)   __CPU_CLR_S (cpu, setsize, cpusetp)
+# define CPU_ISSET_S(cpu, setsize, cpusetp) __CPU_ISSET_S (cpu, setsize, \
+							   cpusetp)
+# define CPU_ZERO_S(setsize, cpusetp)	    __CPU_ZERO_S (setsize, cpusetp)
+# define CPU_COUNT_S(setsize, cpusetp)	    __CPU_COUNT_S (setsize, cpusetp)
+
+# define CPU_EQUAL(cpusetp1, cpusetp2) \
+  __CPU_EQUAL_S (sizeof (cpu_set_t), cpusetp1, cpusetp2)
+# define CPU_EQUAL_S(setsize, cpusetp1, cpusetp2) \
+  __CPU_EQUAL_S (setsize, cpusetp1, cpusetp2)
+
+# define CPU_AND(destset, srcset1, srcset2) \
+  __CPU_OP_S (sizeof (cpu_set_t), destset, srcset1, srcset2, &)
+# define CPU_OR(destset, srcset1, srcset2) \
+  __CPU_OP_S (sizeof (cpu_set_t), destset, srcset1, srcset2, |)
+# define CPU_XOR(destset, srcset1, srcset2) \
+  __CPU_OP_S (sizeof (cpu_set_t), destset, srcset1, srcset2, ^)
+# define CPU_AND_S(setsize, destset, srcset1, srcset2) \
+  __CPU_OP_S (setsize, destset, srcset1, srcset2, &)
+# define CPU_OR_S(setsize, destset, srcset1, srcset2) \
+  __CPU_OP_S (setsize, destset, srcset1, srcset2, |)
+# define CPU_XOR_S(setsize, destset, srcset1, srcset2) \
+  __CPU_OP_S (setsize, destset, srcset1, srcset2, ^)
+
+# define CPU_ALLOC_SIZE(count) __CPU_ALLOC_SIZE (count)
+# define CPU_ALLOC(count) __CPU_ALLOC (count)
+# define CPU_FREE(cpuset) __CPU_FREE (cpuset)
+
+
+/* Set the CPU affinity for a task */
+extern int sched_setaffinity (__pid_t __pid, size_t __cpusetsize,
+			      const cpu_set_t *__cpuset) __THROW;
+
+/* Get the CPU affinity for a task */
+extern int sched_getaffinity (__pid_t __pid, size_t __cpusetsize,
+			      cpu_set_t *__cpuset) __THROW;
+#endif
+
+__END_DECLS
+
+#endif /* sched.h */
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@@ -0,0 +1,92 @@
+/* Copyright (C) 1991-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+/*
+ *	ISO C99 Standard: 7.13 Nonlocal jumps	<setjmp.h>
+ */
+
+#ifndef	_SETJMP_H
+#define	_SETJMP_H	1
+
+#include <features.h>
+
+__BEGIN_DECLS
+
+#include <bits/setjmp.h>		/* Get `__jmp_buf'.  */
+#include <bits/types/struct___jmp_buf_tag.h>
+
+typedef struct __jmp_buf_tag jmp_buf[1];
+
+/* Store the calling environment in ENV, also saving the signal mask.
+   Return 0.  */
+extern int setjmp (jmp_buf __env) __THROWNL;
+
+/* Store the calling environment in ENV, also saving the
+   signal mask if SAVEMASK is nonzero.  Return 0.
+   This is the internal name for `sigsetjmp'.  */
+extern int __sigsetjmp (struct __jmp_buf_tag __env[1], int __savemask) __THROWNL;
+
+/* Store the calling environment in ENV, not saving the signal mask.
+   Return 0.  */
+extern int _setjmp (struct __jmp_buf_tag __env[1]) __THROWNL;
+
+/* Do not save the signal mask.  This is equivalent to the `_setjmp'
+   BSD function.  */
+#define setjmp(env)	_setjmp (env)
+
+
+/* Jump to the environment saved in ENV, making the
+   `setjmp' call there return VAL, or 1 if VAL is 0.  */
+extern void longjmp (struct __jmp_buf_tag __env[1], int __val)
+     __THROWNL __attribute__ ((__noreturn__));
+
+#if defined __USE_MISC || defined __USE_XOPEN
+/* Same.  Usually `_longjmp' is used with `_setjmp', which does not save
+   the signal mask.  But it is how ENV was saved that determines whether
+   `longjmp' restores the mask; `_longjmp' is just an alias.  */
+extern void _longjmp (struct __jmp_buf_tag __env[1], int __val)
+     __THROWNL __attribute__ ((__noreturn__));
+#endif
+
+
+#ifdef	__USE_POSIX
+/* Use the same type for `jmp_buf' and `sigjmp_buf'.
+   The `__mask_was_saved' flag determines whether
+   or not `longjmp' will restore the signal mask.  */
+typedef struct __jmp_buf_tag sigjmp_buf[1];
+
+/* Store the calling environment in ENV, also saving the
+   signal mask if SAVEMASK is nonzero.  Return 0.  */
+# define sigsetjmp(env, savemask)	__sigsetjmp (env, savemask)
+
+/* Jump to the environment saved in ENV, making the
+   sigsetjmp call there return VAL, or 1 if VAL is 0.
+   Restore the signal mask if that sigsetjmp call saved it.
+   This is just an alias `longjmp'.  */
+extern void siglongjmp (sigjmp_buf __env, int __val)
+     __THROWNL __attribute__ ((__noreturn__));
+#endif /* Use POSIX.  */
+
+
+/* Define helper functions to catch unsafe code.  */
+#if __USE_FORTIFY_LEVEL > 0
+# include <bits/setjmp2.h>
+#endif
+
+__END_DECLS
+
+#endif /* setjmp.h  */
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@signal.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@signal.h
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@@ -0,0 +1,395 @@
+/* Copyright (C) 1991-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+/*
+ *	ISO C99 Standard: 7.14 Signal handling <signal.h>
+ */
+
+#ifndef	_SIGNAL_H
+#define _SIGNAL_H
+
+#include <features.h>
+
+__BEGIN_DECLS
+
+#include <bits/types.h>
+#include <bits/signum-generic.h>
+
+#include <bits/types/sig_atomic_t.h>
+
+#if defined __USE_POSIX
+#include <bits/types/sigset_t.h>
+#endif
+
+#if defined __USE_XOPEN || defined __USE_XOPEN2K
+# ifndef __pid_t_defined
+typedef __pid_t pid_t;
+#  define __pid_t_defined
+#endif
+#ifdef __USE_XOPEN
+# endif
+# ifndef __uid_t_defined
+typedef __uid_t uid_t;
+#  define __uid_t_defined
+# endif
+#endif	/* Unix98 */
+
+#ifdef __USE_POSIX199309
+/* We need `struct timespec' later on.  */
+# include <bits/types/struct_timespec.h>
+#endif
+
+#if defined __USE_POSIX199309 || defined __USE_XOPEN_EXTENDED
+# include <bits/types/siginfo_t.h>
+# include <bits/siginfo-consts.h>
+#endif
+
+#ifdef __USE_MISC
+# include <bits/types/sigval_t.h>
+#endif
+
+#ifdef __USE_POSIX199309
+# include <bits/types/sigevent_t.h>
+# include <bits/sigevent-consts.h>
+#endif
+
+
+/* Type of a signal handler.  */
+typedef void (*__sighandler_t) (int);
+
+/* The X/Open definition of `signal' specifies the SVID semantic.  Use
+   the additional function `sysv_signal' when X/Open compatibility is
+   requested.  */
+extern __sighandler_t __sysv_signal (int __sig, __sighandler_t __handler)
+     __THROW;
+#ifdef __USE_GNU
+extern __sighandler_t sysv_signal (int __sig, __sighandler_t __handler)
+     __THROW;
+#endif
+
+/* Set the handler for the signal SIG to HANDLER, returning the old
+   handler, or SIG_ERR on error.
+   By default `signal' has the BSD semantic.  */
+#ifdef __USE_MISC
+extern __sighandler_t signal (int __sig, __sighandler_t __handler)
+     __THROW;
+#else
+/* Make sure the used `signal' implementation is the SVID version. */
+# ifdef __REDIRECT_NTH
+extern __sighandler_t __REDIRECT_NTH (signal,
+				      (int __sig, __sighandler_t __handler),
+				      __sysv_signal);
+# else
+#  define signal __sysv_signal
+# endif
+#endif
+
+#if defined __USE_XOPEN_EXTENDED && !defined __USE_XOPEN2K8
+/* The X/Open definition of `signal' conflicts with the BSD version.
+   So they defined another function `bsd_signal'.  */
+extern __sighandler_t bsd_signal (int __sig, __sighandler_t __handler)
+     __THROW;
+#endif
+
+/* Send signal SIG to process number PID.  If PID is zero,
+   send SIG to all processes in the current process's process group.
+   If PID is < -1, send SIG to all processes in process group - PID.  */
+#ifdef __USE_POSIX
+extern int kill (__pid_t __pid, int __sig) __THROW;
+#endif /* Use POSIX.  */
+
+#if defined __USE_MISC || defined __USE_XOPEN_EXTENDED
+/* Send SIG to all processes in process group PGRP.
+   If PGRP is zero, send SIG to all processes in
+   the current process's process group.  */
+extern int killpg (__pid_t __pgrp, int __sig) __THROW;
+#endif /* Use misc || X/Open Unix.  */
+
+/* Raise signal SIG, i.e., send SIG to yourself.  */
+extern int raise (int __sig) __THROW;
+
+#ifdef __USE_MISC
+/* SVID names for the same things.  */
+extern __sighandler_t ssignal (int __sig, __sighandler_t __handler)
+     __THROW;
+extern int gsignal (int __sig) __THROW;
+#endif /* Use misc.  */
+
+#ifdef __USE_XOPEN2K8
+/* Print a message describing the meaning of the given signal number.  */
+extern void psignal (int __sig, const char *__s);
+
+/* Print a message describing the meaning of the given signal information.  */
+extern void psiginfo (const siginfo_t *__pinfo, const char *__s);
+#endif /* POSIX 2008.  */
+
+
+
+/* The `sigpause' function in X/Open defines the argument as the
+   signal number.  This requires redirecting to another function
+   because the default version in glibc uses an old BSD interface.
+
+   This function is a cancellation point and therefore not marked with
+   __THROW.  */
+
+#ifdef __USE_XOPEN_EXTENDED
+# ifdef __GNUC__
+extern int sigpause (int __sig) __asm__ ("__xpg_sigpause")
+  __attribute_deprecated_msg__ ("Use the sigsuspend function instead");
+# else
+extern int __sigpause (int __sig_or_mask, int __is_sig);
+/* Remove a signal from the signal mask and suspend the process.  */
+#  define sigpause(sig) __sigpause ((sig), 1)
+# endif
+#endif
+
+
+#ifdef __USE_MISC
+/* None of the following functions should be used anymore.  They are here
+   only for compatibility.  A single word (`int') is not guaranteed to be
+   enough to hold a complete signal mask and therefore these functions
+   simply do not work in many situations.  Use `sigprocmask' instead.  */
+
+/* Compute mask for signal SIG.  */
+# define sigmask(sig) \
+  __glibc_macro_warning ("sigmask is deprecated") \
+  ((int)(1u << ((sig) - 1)))
+
+/* Block signals in MASK, returning the old mask.  */
+extern int sigblock (int __mask) __THROW __attribute_deprecated__;
+
+/* Set the mask of blocked signals to MASK, returning the old mask.  */
+extern int sigsetmask (int __mask) __THROW __attribute_deprecated__;
+
+/* Return currently selected signal mask.  */
+extern int siggetmask (void) __THROW __attribute_deprecated__;
+#endif /* Use misc.  */
+
+
+#ifdef __USE_MISC
+# define NSIG	_NSIG
+#endif
+
+#ifdef __USE_GNU
+typedef __sighandler_t sighandler_t;
+#endif
+
+/* 4.4 BSD uses the name `sig_t' for this.  */
+#ifdef __USE_MISC
+typedef __sighandler_t sig_t;
+#endif
+
+#ifdef __USE_POSIX
+
+/* Clear all signals from SET.  */
+extern int sigemptyset (sigset_t *__set) __THROW __nonnull ((1));
+
+/* Set all signals in SET.  */
+extern int sigfillset (sigset_t *__set) __THROW __nonnull ((1));
+
+/* Add SIGNO to SET.  */
+extern int sigaddset (sigset_t *__set, int __signo) __THROW __nonnull ((1));
+
+/* Remove SIGNO from SET.  */
+extern int sigdelset (sigset_t *__set, int __signo) __THROW __nonnull ((1));
+
+/* Return 1 if SIGNO is in SET, 0 if not.  */
+extern int sigismember (const sigset_t *__set, int __signo)
+     __THROW __nonnull ((1));
+
+# ifdef __USE_GNU
+/* Return non-empty value is SET is not empty.  */
+extern int sigisemptyset (const sigset_t *__set) __THROW __nonnull ((1));
+
+/* Build new signal set by combining the two inputs set using logical AND.  */
+extern int sigandset (sigset_t *__set, const sigset_t *__left,
+		      const sigset_t *__right) __THROW __nonnull ((1, 2, 3));
+
+/* Build new signal set by combining the two inputs set using logical OR.  */
+extern int sigorset (sigset_t *__set, const sigset_t *__left,
+		     const sigset_t *__right) __THROW __nonnull ((1, 2, 3));
+# endif /* GNU */
+
+/* Get the system-specific definitions of `struct sigaction'
+   and the `SA_*' and `SIG_*'. constants.  */
+# include <bits/sigaction.h>
+
+/* Get and/or change the set of blocked signals.  */
+extern int sigprocmask (int __how, const sigset_t *__restrict __set,
+			sigset_t *__restrict __oset) __THROW;
+
+/* Change the set of blocked signals to SET,
+   wait until a signal arrives, and restore the set of blocked signals.
+
+   This function is a cancellation point and therefore not marked with
+   __THROW.  */
+extern int sigsuspend (const sigset_t *__set) __nonnull ((1));
+
+/* Get and/or set the action for signal SIG.  */
+extern int sigaction (int __sig, const struct sigaction *__restrict __act,
+		      struct sigaction *__restrict __oact) __THROW;
+
+/* Put in SET all signals that are blocked and waiting to be delivered.  */
+extern int sigpending (sigset_t *__set) __THROW __nonnull ((1));
+
+
+# ifdef __USE_POSIX199506
+/* Select any of pending signals from SET or wait for any to arrive.
+
+   This function is a cancellation point and therefore not marked with
+   __THROW.  */
+extern int sigwait (const sigset_t *__restrict __set, int *__restrict __sig)
+     __nonnull ((1, 2));
+# endif /* Use POSIX 1995.  */
+
+# ifdef __USE_POSIX199309
+/* Select any of pending signals from SET and place information in INFO.
+
+   This function is a cancellation point and therefore not marked with
+   __THROW.  */
+extern int sigwaitinfo (const sigset_t *__restrict __set,
+			siginfo_t *__restrict __info) __nonnull ((1));
+
+/* Select any of pending signals from SET and place information in INFO.
+   Wait the time specified by TIMEOUT if no signal is pending.
+
+   This function is a cancellation point and therefore not marked with
+   __THROW.  */
+#  ifndef __USE_TIME_BITS64
+extern int sigtimedwait (const sigset_t *__restrict __set,
+			 siginfo_t *__restrict __info,
+			 const struct timespec *__restrict __timeout)
+     __nonnull ((1));
+#  else
+#   ifdef __REDIRECT
+extern int __REDIRECT (sigtimedwait,
+                       (const sigset_t *__restrict __set,
+                        siginfo_t *__restrict __info,
+                        const struct timespec *__restrict __timeout),
+                       __sigtimedwait64)
+     __nonnull ((1));
+#   else
+#    define sigtimedwait __sigtimedwait64
+#   endif
+#  endif
+
+/* Send signal SIG to the process PID.  Associate data in VAL with the
+   signal.  */
+extern int sigqueue (__pid_t __pid, int __sig, const union sigval __val)
+     __THROW;
+# endif	/* Use POSIX 199306.  */
+
+#endif /* Use POSIX.  */
+
+#ifdef __USE_MISC
+
+/* Get machine-dependent `struct sigcontext' and signal subcodes.  */
+# include <bits/sigcontext.h>
+
+/* Restore the state saved in SCP.  */
+extern int sigreturn (struct sigcontext *__scp) __THROW;
+
+#endif /* Use misc.  */
+
+
+#if defined __USE_XOPEN_EXTENDED || defined __USE_XOPEN2K8
+# define __need_size_t
+# include <stddef.h>
+
+# include <bits/types/stack_t.h>
+# if defined __USE_XOPEN || defined __USE_XOPEN2K8
+/* This will define `ucontext_t' and `mcontext_t'.  */
+#  include <sys/ucontext.h>
+# endif
+#endif /* Use POSIX.1-2008 or X/Open Unix.  */
+
+#if defined __USE_XOPEN_EXTENDED || defined __USE_MISC
+/* If INTERRUPT is nonzero, make signal SIG interrupt system calls
+   (causing them to fail with EINTR); if INTERRUPT is zero, make system
+   calls be restarted after signal SIG.  */
+extern int siginterrupt (int __sig, int __interrupt) __THROW
+  __attribute_deprecated_msg__ ("Use sigaction with SA_RESTART instead");
+
+# include <bits/sigstack.h>
+# include <bits/sigstksz.h>
+# include <bits/ss_flags.h>
+
+/* Alternate signal handler stack interface.
+   This interface should always be preferred over `sigstack'.  */
+extern int sigaltstack (const stack_t *__restrict __ss,
+			stack_t *__restrict __oss) __THROW;
+#endif /* __USE_XOPEN_EXTENDED || __USE_MISC */
+
+#if ((defined __USE_XOPEN_EXTENDED && !defined __USE_XOPEN2K8)	\
+     || defined __USE_MISC)
+# include <bits/types/struct_sigstack.h>
+#endif
+
+#if ((defined __USE_XOPEN_EXTENDED && !defined __USE_XOPEN2K)	\
+     || defined __USE_MISC)
+/* Run signals handlers on the stack specified by SS (if not NULL).
+   If OSS is not NULL, it is filled in with the old signal stack status.
+   This interface is obsolete and on many platform not implemented.  */
+extern int sigstack (struct sigstack *__ss, struct sigstack *__oss)
+     __THROW __attribute_deprecated__;
+#endif
+
+#ifdef __USE_XOPEN_EXTENDED
+/* Simplified interface for signal management.  */
+
+/* Add SIG to the calling process' signal mask.  */
+extern int sighold (int __sig) __THROW
+  __attribute_deprecated_msg__ ("Use the sigprocmask function instead");
+
+/* Remove SIG from the calling process' signal mask.  */
+extern int sigrelse (int __sig) __THROW
+  __attribute_deprecated_msg__ ("Use the sigprocmask function instead");
+
+/* Set the disposition of SIG to SIG_IGN.  */
+extern int sigignore (int __sig) __THROW
+  __attribute_deprecated_msg__ ("Use the signal function instead");
+
+/* Set the disposition of SIG.  */
+extern __sighandler_t sigset (int __sig, __sighandler_t __disp) __THROW
+  __attribute_deprecated_msg__
+    ("Use the signal and sigprocmask functions instead");
+#endif
+
+#if defined __USE_POSIX199506 || defined __USE_UNIX98
+/* Some of the functions for handling signals in threaded programs must
+   be defined here.  */
+# include <bits/pthreadtypes.h>
+# include <bits/sigthread.h>
+#endif /* use Unix98 */
+
+/* The following functions are used internally in the C library and in
+   other code which need deep insights.  */
+
+/* Return number of available real-time signal with highest priority.  */
+extern int __libc_current_sigrtmin (void) __THROW;
+/* Return number of available real-time signal with lowest priority.  */
+extern int __libc_current_sigrtmax (void) __THROW;
+
+#define SIGRTMIN        (__libc_current_sigrtmin ())
+#define SIGRTMAX        (__libc_current_sigrtmax ())
+
+/* System-specific extensions.  */
+#include <bits/signal_ext.h>
+
+__END_DECLS
+
+#endif /* not signal.h */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@signal.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@signal.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@stdc-predef.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@stdc-predef.h
new file mode 100644
index 0000000000000000000000000000000000000000..d76933d4682871702c4b127938273b6b11c8addd
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@stdc-predef.h
@@ -0,0 +1,64 @@
+/* Copyright (C) 1991-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef	_STDC_PREDEF_H
+#define	_STDC_PREDEF_H	1
+
+/* This header is separate from features.h so that the compiler can
+   include it implicitly at the start of every compilation.  It must
+   not itself include <features.h> or any other header that includes
+   <features.h> because the implicit include comes before any feature
+   test macros that may be defined in a source file before it first
+   explicitly includes a system header.  GCC knows the name of this
+   header in order to preinclude it.  */
+
+/* glibc's intent is to support the IEC 559 math functionality, real
+   and complex.  If the GCC (4.9 and later) predefined macros
+   specifying compiler intent are available, use them to determine
+   whether the overall intent is to support these features; otherwise,
+   presume an older compiler has intent to support these features and
+   define these macros by default.  */
+
+#ifdef __GCC_IEC_559
+# if __GCC_IEC_559 > 0
+#  define __STDC_IEC_559__		1
+#  define __STDC_IEC_60559_BFP__ 	201404L
+# endif
+#else
+# define __STDC_IEC_559__		1
+# define __STDC_IEC_60559_BFP__ 	201404L
+#endif
+
+#ifdef __GCC_IEC_559_COMPLEX
+# if __GCC_IEC_559_COMPLEX > 0
+#  define __STDC_IEC_559_COMPLEX__	1
+#  define __STDC_IEC_60559_COMPLEX__	201404L
+# endif
+#else
+# define __STDC_IEC_559_COMPLEX__	1
+# define __STDC_IEC_60559_COMPLEX__	201404L
+#endif
+
+/* wchar_t uses Unicode 10.0.0.  Version 10.0 of the Unicode Standard is
+   synchronized with ISO/IEC 10646:2017, fifth edition, plus
+   the following additions from Amendment 1 to the fifth edition:
+   - 56 emoji characters
+   - 285 hentaigana
+   - 3 additional Zanabazar Square characters */
+#define __STDC_ISO_10646__		201706L
+
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@stdc-predef.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@stdc-predef.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@stdint.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@stdint.h
new file mode 100644
index 0000000000000000000000000000000000000000..2d666f79fd97aa419ad1febcb420914fbe1a0dd1
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@stdint.h
@@ -0,0 +1,319 @@
+/* Copyright (C) 1997-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+/*
+ *	ISO C99: 7.18 Integer types <stdint.h>
+ */
+
+#ifndef _STDINT_H
+#define _STDINT_H	1
+
+#define __GLIBC_INTERNAL_STARTING_HEADER_IMPLEMENTATION
+#include <bits/libc-header-start.h>
+#include <bits/types.h>
+#include <bits/wchar.h>
+#include <bits/wordsize.h>
+
+/* Exact integral types.  */
+
+/* Signed.  */
+#include <bits/stdint-intn.h>
+
+/* Unsigned.  */
+#include <bits/stdint-uintn.h>
+
+
+/* Small types.  */
+
+/* Signed.  */
+typedef __int_least8_t int_least8_t;
+typedef __int_least16_t int_least16_t;
+typedef __int_least32_t int_least32_t;
+typedef __int_least64_t int_least64_t;
+
+/* Unsigned.  */
+typedef __uint_least8_t uint_least8_t;
+typedef __uint_least16_t uint_least16_t;
+typedef __uint_least32_t uint_least32_t;
+typedef __uint_least64_t uint_least64_t;
+
+
+/* Fast types.  */
+
+/* Signed.  */
+typedef signed char		int_fast8_t;
+#if __WORDSIZE == 64
+typedef long int		int_fast16_t;
+typedef long int		int_fast32_t;
+typedef long int		int_fast64_t;
+#else
+typedef int			int_fast16_t;
+typedef int			int_fast32_t;
+__extension__
+typedef long long int		int_fast64_t;
+#endif
+
+/* Unsigned.  */
+typedef unsigned char		uint_fast8_t;
+#if __WORDSIZE == 64
+typedef unsigned long int	uint_fast16_t;
+typedef unsigned long int	uint_fast32_t;
+typedef unsigned long int	uint_fast64_t;
+#else
+typedef unsigned int		uint_fast16_t;
+typedef unsigned int		uint_fast32_t;
+__extension__
+typedef unsigned long long int	uint_fast64_t;
+#endif
+
+
+/* Types for `void *' pointers.  */
+#if __WORDSIZE == 64
+# ifndef __intptr_t_defined
+typedef long int		intptr_t;
+#  define __intptr_t_defined
+# endif
+typedef unsigned long int	uintptr_t;
+#else
+# ifndef __intptr_t_defined
+typedef int			intptr_t;
+#  define __intptr_t_defined
+# endif
+typedef unsigned int		uintptr_t;
+#endif
+
+
+/* Largest integral types.  */
+typedef __intmax_t		intmax_t;
+typedef __uintmax_t		uintmax_t;
+
+
+# if __WORDSIZE == 64
+#  define __INT64_C(c)	c ## L
+#  define __UINT64_C(c)	c ## UL
+# else
+#  define __INT64_C(c)	c ## LL
+#  define __UINT64_C(c)	c ## ULL
+# endif
+
+/* Limits of integral types.  */
+
+/* Minimum of signed integral types.  */
+# define INT8_MIN		(-128)
+# define INT16_MIN		(-32767-1)
+# define INT32_MIN		(-2147483647-1)
+# define INT64_MIN		(-__INT64_C(9223372036854775807)-1)
+/* Maximum of signed integral types.  */
+# define INT8_MAX		(127)
+# define INT16_MAX		(32767)
+# define INT32_MAX		(2147483647)
+# define INT64_MAX		(__INT64_C(9223372036854775807))
+
+/* Maximum of unsigned integral types.  */
+# define UINT8_MAX		(255)
+# define UINT16_MAX		(65535)
+# define UINT32_MAX		(4294967295U)
+# define UINT64_MAX		(__UINT64_C(18446744073709551615))
+
+
+/* Minimum of signed integral types having a minimum size.  */
+# define INT_LEAST8_MIN		(-128)
+# define INT_LEAST16_MIN	(-32767-1)
+# define INT_LEAST32_MIN	(-2147483647-1)
+# define INT_LEAST64_MIN	(-__INT64_C(9223372036854775807)-1)
+/* Maximum of signed integral types having a minimum size.  */
+# define INT_LEAST8_MAX		(127)
+# define INT_LEAST16_MAX	(32767)
+# define INT_LEAST32_MAX	(2147483647)
+# define INT_LEAST64_MAX	(__INT64_C(9223372036854775807))
+
+/* Maximum of unsigned integral types having a minimum size.  */
+# define UINT_LEAST8_MAX	(255)
+# define UINT_LEAST16_MAX	(65535)
+# define UINT_LEAST32_MAX	(4294967295U)
+# define UINT_LEAST64_MAX	(__UINT64_C(18446744073709551615))
+
+
+/* Minimum of fast signed integral types having a minimum size.  */
+# define INT_FAST8_MIN		(-128)
+# if __WORDSIZE == 64
+#  define INT_FAST16_MIN	(-9223372036854775807L-1)
+#  define INT_FAST32_MIN	(-9223372036854775807L-1)
+# else
+#  define INT_FAST16_MIN	(-2147483647-1)
+#  define INT_FAST32_MIN	(-2147483647-1)
+# endif
+# define INT_FAST64_MIN		(-__INT64_C(9223372036854775807)-1)
+/* Maximum of fast signed integral types having a minimum size.  */
+# define INT_FAST8_MAX		(127)
+# if __WORDSIZE == 64
+#  define INT_FAST16_MAX	(9223372036854775807L)
+#  define INT_FAST32_MAX	(9223372036854775807L)
+# else
+#  define INT_FAST16_MAX	(2147483647)
+#  define INT_FAST32_MAX	(2147483647)
+# endif
+# define INT_FAST64_MAX		(__INT64_C(9223372036854775807))
+
+/* Maximum of fast unsigned integral types having a minimum size.  */
+# define UINT_FAST8_MAX		(255)
+# if __WORDSIZE == 64
+#  define UINT_FAST16_MAX	(18446744073709551615UL)
+#  define UINT_FAST32_MAX	(18446744073709551615UL)
+# else
+#  define UINT_FAST16_MAX	(4294967295U)
+#  define UINT_FAST32_MAX	(4294967295U)
+# endif
+# define UINT_FAST64_MAX	(__UINT64_C(18446744073709551615))
+
+
+/* Values to test for integral types holding `void *' pointer.  */
+# if __WORDSIZE == 64
+#  define INTPTR_MIN		(-9223372036854775807L-1)
+#  define INTPTR_MAX		(9223372036854775807L)
+#  define UINTPTR_MAX		(18446744073709551615UL)
+# else
+#  define INTPTR_MIN		(-2147483647-1)
+#  define INTPTR_MAX		(2147483647)
+#  define UINTPTR_MAX		(4294967295U)
+# endif
+
+
+/* Minimum for largest signed integral type.  */
+# define INTMAX_MIN		(-__INT64_C(9223372036854775807)-1)
+/* Maximum for largest signed integral type.  */
+# define INTMAX_MAX		(__INT64_C(9223372036854775807))
+
+/* Maximum for largest unsigned integral type.  */
+# define UINTMAX_MAX		(__UINT64_C(18446744073709551615))
+
+
+/* Limits of other integer types.  */
+
+/* Limits of `ptrdiff_t' type.  */
+# if __WORDSIZE == 64
+#  define PTRDIFF_MIN		(-9223372036854775807L-1)
+#  define PTRDIFF_MAX		(9223372036854775807L)
+# else
+#  if __WORDSIZE32_PTRDIFF_LONG
+#   define PTRDIFF_MIN		(-2147483647L-1)
+#   define PTRDIFF_MAX		(2147483647L)
+#  else
+#   define PTRDIFF_MIN		(-2147483647-1)
+#   define PTRDIFF_MAX		(2147483647)
+#  endif
+# endif
+
+/* Limits of `sig_atomic_t'.  */
+# define SIG_ATOMIC_MIN		(-2147483647-1)
+# define SIG_ATOMIC_MAX		(2147483647)
+
+/* Limit of `size_t' type.  */
+# if __WORDSIZE == 64
+#  define SIZE_MAX		(18446744073709551615UL)
+# else
+#  if __WORDSIZE32_SIZE_ULONG
+#   define SIZE_MAX		(4294967295UL)
+#  else
+#   define SIZE_MAX		(4294967295U)
+#  endif
+# endif
+
+/* Limits of `wchar_t'.  */
+# ifndef WCHAR_MIN
+/* These constants might also be defined in <wchar.h>.  */
+#  define WCHAR_MIN		__WCHAR_MIN
+#  define WCHAR_MAX		__WCHAR_MAX
+# endif
+
+/* Limits of `wint_t'.  */
+# define WINT_MIN		(0u)
+# define WINT_MAX		(4294967295u)
+
+/* Signed.  */
+# define INT8_C(c)	c
+# define INT16_C(c)	c
+# define INT32_C(c)	c
+# if __WORDSIZE == 64
+#  define INT64_C(c)	c ## L
+# else
+#  define INT64_C(c)	c ## LL
+# endif
+
+/* Unsigned.  */
+# define UINT8_C(c)	c
+# define UINT16_C(c)	c
+# define UINT32_C(c)	c ## U
+# if __WORDSIZE == 64
+#  define UINT64_C(c)	c ## UL
+# else
+#  define UINT64_C(c)	c ## ULL
+# endif
+
+/* Maximal type.  */
+# if __WORDSIZE == 64
+#  define INTMAX_C(c)	c ## L
+#  define UINTMAX_C(c)	c ## UL
+# else
+#  define INTMAX_C(c)	c ## LL
+#  define UINTMAX_C(c)	c ## ULL
+# endif
+
+#if __GLIBC_USE (IEC_60559_BFP_EXT_C2X)
+
+# define INT8_WIDTH 8
+# define UINT8_WIDTH 8
+# define INT16_WIDTH 16
+# define UINT16_WIDTH 16
+# define INT32_WIDTH 32
+# define UINT32_WIDTH 32
+# define INT64_WIDTH 64
+# define UINT64_WIDTH 64
+
+# define INT_LEAST8_WIDTH 8
+# define UINT_LEAST8_WIDTH 8
+# define INT_LEAST16_WIDTH 16
+# define UINT_LEAST16_WIDTH 16
+# define INT_LEAST32_WIDTH 32
+# define UINT_LEAST32_WIDTH 32
+# define INT_LEAST64_WIDTH 64
+# define UINT_LEAST64_WIDTH 64
+
+# define INT_FAST8_WIDTH 8
+# define UINT_FAST8_WIDTH 8
+# define INT_FAST16_WIDTH __WORDSIZE
+# define UINT_FAST16_WIDTH __WORDSIZE
+# define INT_FAST32_WIDTH __WORDSIZE
+# define UINT_FAST32_WIDTH __WORDSIZE
+# define INT_FAST64_WIDTH 64
+# define UINT_FAST64_WIDTH 64
+
+# define INTPTR_WIDTH __WORDSIZE
+# define UINTPTR_WIDTH __WORDSIZE
+
+# define INTMAX_WIDTH 64
+# define UINTMAX_WIDTH 64
+
+# define PTRDIFF_WIDTH __WORDSIZE
+# define SIG_ATOMIC_WIDTH 32
+# define SIZE_WIDTH __WORDSIZE
+# define WCHAR_WIDTH 32
+# define WINT_WIDTH 32
+
+#endif
+
+#endif /* stdint.h */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@stdint.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@stdint.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@stdio.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@stdio.h
new file mode 100644
index 0000000000000000000000000000000000000000..0e0f16b46410c8e289a7f2bb35d96e255135b70e
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@stdio.h
@@ -0,0 +1,911 @@
+/* Define ISO C stdio on top of C++ iostreams.
+   Copyright (C) 1991-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+/*
+ *	ISO C99 Standard: 7.19 Input/output	<stdio.h>
+ */
+
+#ifndef _STDIO_H
+#define _STDIO_H	1
+
+#define __GLIBC_INTERNAL_STARTING_HEADER_IMPLEMENTATION
+#include <bits/libc-header-start.h>
+
+__BEGIN_DECLS
+
+#define __need_size_t
+#define __need_NULL
+#include <stddef.h>
+
+#define __need___va_list
+#include <stdarg.h>
+
+#include <bits/types.h>
+#include <bits/types/__fpos_t.h>
+#include <bits/types/__fpos64_t.h>
+#include <bits/types/__FILE.h>
+#include <bits/types/FILE.h>
+#include <bits/types/struct_FILE.h>
+
+#ifdef __USE_GNU
+# include <bits/types/cookie_io_functions_t.h>
+#endif
+
+#if defined __USE_XOPEN || defined __USE_XOPEN2K8
+# ifdef __GNUC__
+#  ifndef _VA_LIST_DEFINED
+typedef __gnuc_va_list va_list;
+#   define _VA_LIST_DEFINED
+#  endif
+# else
+#  include <stdarg.h>
+# endif
+#endif
+
+#if defined __USE_UNIX98 || defined __USE_XOPEN2K
+# ifndef __off_t_defined
+# ifndef __USE_FILE_OFFSET64
+typedef __off_t off_t;
+# else
+typedef __off64_t off_t;
+# endif
+# define __off_t_defined
+# endif
+# if defined __USE_LARGEFILE64 && !defined __off64_t_defined
+typedef __off64_t off64_t;
+# define __off64_t_defined
+# endif
+#endif
+
+#ifdef __USE_XOPEN2K8
+# ifndef __ssize_t_defined
+typedef __ssize_t ssize_t;
+# define __ssize_t_defined
+# endif
+#endif
+
+/* The type of the second argument to `fgetpos' and `fsetpos'.  */
+#ifndef __USE_FILE_OFFSET64
+typedef __fpos_t fpos_t;
+#else
+typedef __fpos64_t fpos_t;
+#endif
+#ifdef __USE_LARGEFILE64
+typedef __fpos64_t fpos64_t;
+#endif
+
+/* The possibilities for the third argument to `setvbuf'.  */
+#define _IOFBF 0		/* Fully buffered.  */
+#define _IOLBF 1		/* Line buffered.  */
+#define _IONBF 2		/* No buffering.  */
+
+
+/* Default buffer size.  */
+#define BUFSIZ 8192
+
+
+/* The value returned by fgetc and similar functions to indicate the
+   end of the file.  */
+#define EOF (-1)
+
+
+/* The possibilities for the third argument to `fseek'.
+   These values should not be changed.  */
+#define SEEK_SET	0	/* Seek from beginning of file.  */
+#define SEEK_CUR	1	/* Seek from current position.  */
+#define SEEK_END	2	/* Seek from end of file.  */
+#ifdef __USE_GNU
+# define SEEK_DATA	3	/* Seek to next data.  */
+# define SEEK_HOLE	4	/* Seek to next hole.  */
+#endif
+
+
+#if defined __USE_MISC || defined __USE_XOPEN
+/* Default path prefix for `tempnam' and `tmpnam'.  */
+# define P_tmpdir	"/tmp"
+#endif
+
+
+/* Get the values:
+   L_tmpnam	How long an array of chars must be to be passed to `tmpnam'.
+   TMP_MAX	The minimum number of unique filenames generated by tmpnam
+		(and tempnam when it uses tmpnam's name space),
+		or tempnam (the two are separate).
+   L_ctermid	How long an array to pass to `ctermid'.
+   L_cuserid	How long an array to pass to `cuserid'.
+   FOPEN_MAX	Minimum number of files that can be open at once.
+   FILENAME_MAX	Maximum length of a filename.  */
+#include <bits/stdio_lim.h>
+
+
+#if __GLIBC_USE (ISOC2X)
+/* Maximum length of printf output for a NaN.  */
+# define _PRINTF_NAN_LEN_MAX 4
+#endif
+
+
+/* Standard streams.  */
+extern FILE *stdin;		/* Standard input stream.  */
+extern FILE *stdout;		/* Standard output stream.  */
+extern FILE *stderr;		/* Standard error output stream.  */
+/* C89/C99 say they're macros.  Make them happy.  */
+#define stdin stdin
+#define stdout stdout
+#define stderr stderr
+
+/* Remove file FILENAME.  */
+extern int remove (const char *__filename) __THROW;
+/* Rename file OLD to NEW.  */
+extern int rename (const char *__old, const char *__new) __THROW;
+
+#ifdef __USE_ATFILE
+/* Rename file OLD relative to OLDFD to NEW relative to NEWFD.  */
+extern int renameat (int __oldfd, const char *__old, int __newfd,
+		     const char *__new) __THROW;
+#endif
+
+#ifdef __USE_GNU
+/* Flags for renameat2.  */
+# define RENAME_NOREPLACE (1 << 0)
+# define RENAME_EXCHANGE (1 << 1)
+# define RENAME_WHITEOUT (1 << 2)
+
+/* Rename file OLD relative to OLDFD to NEW relative to NEWFD, with
+   additional flags.  */
+extern int renameat2 (int __oldfd, const char *__old, int __newfd,
+		      const char *__new, unsigned int __flags) __THROW;
+#endif
+
+/* Close STREAM.
+
+   This function is a possible cancellation point and therefore not
+   marked with __THROW.  */
+extern int fclose (FILE *__stream);
+
+#undef __attr_dealloc_fclose
+#define __attr_dealloc_fclose __attr_dealloc (fclose, 1)
+
+/* Create a temporary file and open it read/write.
+
+   This function is a possible cancellation point and therefore not
+   marked with __THROW.  */
+#ifndef __USE_FILE_OFFSET64
+extern FILE *tmpfile (void)
+  __attribute_malloc__ __attr_dealloc_fclose __wur;
+#else
+# ifdef __REDIRECT
+extern FILE *__REDIRECT (tmpfile, (void), tmpfile64)
+  __attribute_malloc__ __attr_dealloc_fclose __wur;
+# else
+#  define tmpfile tmpfile64
+# endif
+#endif
+
+#ifdef __USE_LARGEFILE64
+extern FILE *tmpfile64 (void)
+   __attribute_malloc__ __attr_dealloc_fclose __wur;
+#endif
+
+/* Generate a temporary filename.  */
+extern char *tmpnam (char[L_tmpnam]) __THROW __wur;
+
+#ifdef __USE_MISC
+/* This is the reentrant variant of `tmpnam'.  The only difference is
+   that it does not allow S to be NULL.  */
+extern char *tmpnam_r (char __s[L_tmpnam]) __THROW __wur;
+#endif
+
+
+#if defined __USE_MISC || defined __USE_XOPEN
+/* Generate a unique temporary filename using up to five characters of PFX
+   if it is not NULL.  The directory to put this file in is searched for
+   as follows: First the environment variable "TMPDIR" is checked.
+   If it contains the name of a writable directory, that directory is used.
+   If not and if DIR is not NULL, that value is checked.  If that fails,
+   P_tmpdir is tried and finally "/tmp".  The storage for the filename
+   is allocated by `malloc'.  */
+extern char *tempnam (const char *__dir, const char *__pfx)
+   __THROW __attribute_malloc__ __wur __attr_dealloc_free;
+#endif
+
+/* Flush STREAM, or all streams if STREAM is NULL.
+
+   This function is a possible cancellation point and therefore not
+   marked with __THROW.  */
+extern int fflush (FILE *__stream);
+
+#ifdef __USE_MISC
+/* Faster versions when locking is not required.
+
+   This function is not part of POSIX and therefore no official
+   cancellation point.  But due to similarity with an POSIX interface
+   or due to the implementation it is a cancellation point and
+   therefore not marked with __THROW.  */
+extern int fflush_unlocked (FILE *__stream);
+#endif
+
+#ifdef __USE_GNU
+/* Close all streams.
+
+   This function is not part of POSIX and therefore no official
+   cancellation point.  But due to similarity with an POSIX interface
+   or due to the implementation it is a cancellation point and
+   therefore not marked with __THROW.  */
+extern int fcloseall (void);
+#endif
+
+
+#ifndef __USE_FILE_OFFSET64
+/* Open a file and create a new stream for it.
+
+   This function is a possible cancellation point and therefore not
+   marked with __THROW.  */
+extern FILE *fopen (const char *__restrict __filename,
+		    const char *__restrict __modes)
+  __attribute_malloc__ __attr_dealloc_fclose __wur;
+/* Open a file, replacing an existing stream with it.
+
+   This function is a possible cancellation point and therefore not
+   marked with __THROW.  */
+extern FILE *freopen (const char *__restrict __filename,
+		      const char *__restrict __modes,
+		      FILE *__restrict __stream) __wur;
+#else
+# ifdef __REDIRECT
+extern FILE *__REDIRECT (fopen, (const char *__restrict __filename,
+				 const char *__restrict __modes), fopen64)
+  __attribute_malloc__ __attr_dealloc_fclose __wur;
+extern FILE *__REDIRECT (freopen, (const char *__restrict __filename,
+				   const char *__restrict __modes,
+				   FILE *__restrict __stream), freopen64)
+  __wur;
+# else
+#  define fopen fopen64
+#  define freopen freopen64
+# endif
+#endif
+#ifdef __USE_LARGEFILE64
+extern FILE *fopen64 (const char *__restrict __filename,
+		      const char *__restrict __modes)
+  __attribute_malloc__ __attr_dealloc_fclose __wur;
+extern FILE *freopen64 (const char *__restrict __filename,
+			const char *__restrict __modes,
+			FILE *__restrict __stream) __wur;
+#endif
+
+#ifdef	__USE_POSIX
+/* Create a new stream that refers to an existing system file descriptor.  */
+extern FILE *fdopen (int __fd, const char *__modes) __THROW
+  __attribute_malloc__ __attr_dealloc_fclose __wur;
+#endif
+
+#ifdef	__USE_GNU
+/* Create a new stream that refers to the given magic cookie,
+   and uses the given functions for input and output.  */
+extern FILE *fopencookie (void *__restrict __magic_cookie,
+			  const char *__restrict __modes,
+			  cookie_io_functions_t __io_funcs) __THROW
+  __attribute_malloc__ __attr_dealloc_fclose __wur;
+#endif
+
+#if defined __USE_XOPEN2K8 || __GLIBC_USE (LIB_EXT2)
+/* Create a new stream that refers to a memory buffer.  */
+extern FILE *fmemopen (void *__s, size_t __len, const char *__modes)
+  __THROW __attribute_malloc__ __attr_dealloc_fclose __wur;
+
+/* Open a stream that writes into a malloc'd buffer that is expanded as
+   necessary.  *BUFLOC and *SIZELOC are updated with the buffer's location
+   and the number of characters written on fflush or fclose.  */
+extern FILE *open_memstream (char **__bufloc, size_t *__sizeloc) __THROW
+  __attribute_malloc__ __attr_dealloc_fclose __wur;
+
+#ifdef _WCHAR_H
+/* Like OPEN_MEMSTREAM, but the stream is wide oriented and produces
+   a wide character string.  Declared here only to add attribute malloc
+   and only if <wchar.h> has been previously #included.  */
+extern __FILE *open_wmemstream (wchar_t **__bufloc, size_t *__sizeloc) __THROW
+  __attribute_malloc__ __attr_dealloc_fclose;
+# endif
+#endif
+
+/* If BUF is NULL, make STREAM unbuffered.
+   Else make it use buffer BUF, of size BUFSIZ.  */
+extern void setbuf (FILE *__restrict __stream, char *__restrict __buf) __THROW;
+/* Make STREAM use buffering mode MODE.
+   If BUF is not NULL, use N bytes of it for buffering;
+   else allocate an internal buffer N bytes long.  */
+extern int setvbuf (FILE *__restrict __stream, char *__restrict __buf,
+		    int __modes, size_t __n) __THROW;
+
+#ifdef	__USE_MISC
+/* If BUF is NULL, make STREAM unbuffered.
+   Else make it use SIZE bytes of BUF for buffering.  */
+extern void setbuffer (FILE *__restrict __stream, char *__restrict __buf,
+		       size_t __size) __THROW;
+
+/* Make STREAM line-buffered.  */
+extern void setlinebuf (FILE *__stream) __THROW;
+#endif
+
+
+/* Write formatted output to STREAM.
+
+   This function is a possible cancellation point and therefore not
+   marked with __THROW.  */
+extern int fprintf (FILE *__restrict __stream,
+		    const char *__restrict __format, ...);
+/* Write formatted output to stdout.
+
+   This function is a possible cancellation point and therefore not
+   marked with __THROW.  */
+extern int printf (const char *__restrict __format, ...);
+/* Write formatted output to S.  */
+extern int sprintf (char *__restrict __s,
+		    const char *__restrict __format, ...) __THROWNL;
+
+/* Write formatted output to S from argument list ARG.
+
+   This function is a possible cancellation point and therefore not
+   marked with __THROW.  */
+extern int vfprintf (FILE *__restrict __s, const char *__restrict __format,
+		     __gnuc_va_list __arg);
+/* Write formatted output to stdout from argument list ARG.
+
+   This function is a possible cancellation point and therefore not
+   marked with __THROW.  */
+extern int vprintf (const char *__restrict __format, __gnuc_va_list __arg);
+/* Write formatted output to S from argument list ARG.  */
+extern int vsprintf (char *__restrict __s, const char *__restrict __format,
+		     __gnuc_va_list __arg) __THROWNL;
+
+#if defined __USE_ISOC99 || defined __USE_UNIX98
+/* Maximum chars of output to write in MAXLEN.  */
+extern int snprintf (char *__restrict __s, size_t __maxlen,
+		     const char *__restrict __format, ...)
+     __THROWNL __attribute__ ((__format__ (__printf__, 3, 4)));
+
+extern int vsnprintf (char *__restrict __s, size_t __maxlen,
+		      const char *__restrict __format, __gnuc_va_list __arg)
+     __THROWNL __attribute__ ((__format__ (__printf__, 3, 0)));
+#endif
+
+#if __GLIBC_USE (LIB_EXT2)
+/* Write formatted output to a string dynamically allocated with `malloc'.
+   Store the address of the string in *PTR.  */
+extern int vasprintf (char **__restrict __ptr, const char *__restrict __f,
+		      __gnuc_va_list __arg)
+     __THROWNL __attribute__ ((__format__ (__printf__, 2, 0))) __wur;
+extern int __asprintf (char **__restrict __ptr,
+		       const char *__restrict __fmt, ...)
+     __THROWNL __attribute__ ((__format__ (__printf__, 2, 3))) __wur;
+extern int asprintf (char **__restrict __ptr,
+		     const char *__restrict __fmt, ...)
+     __THROWNL __attribute__ ((__format__ (__printf__, 2, 3))) __wur;
+#endif
+
+#ifdef __USE_XOPEN2K8
+/* Write formatted output to a file descriptor.  */
+extern int vdprintf (int __fd, const char *__restrict __fmt,
+		     __gnuc_va_list __arg)
+     __attribute__ ((__format__ (__printf__, 2, 0)));
+extern int dprintf (int __fd, const char *__restrict __fmt, ...)
+     __attribute__ ((__format__ (__printf__, 2, 3)));
+#endif
+
+
+/* Read formatted input from STREAM.
+
+   This function is a possible cancellation point and therefore not
+   marked with __THROW.  */
+extern int fscanf (FILE *__restrict __stream,
+		   const char *__restrict __format, ...) __wur;
+/* Read formatted input from stdin.
+
+   This function is a possible cancellation point and therefore not
+   marked with __THROW.  */
+extern int scanf (const char *__restrict __format, ...) __wur;
+/* Read formatted input from S.  */
+extern int sscanf (const char *__restrict __s,
+		   const char *__restrict __format, ...) __THROW;
+
+/* For historical reasons, the C99-compliant versions of the scanf
+   functions are at alternative names.  When __LDBL_COMPAT or
+   __LDOUBLE_REDIRECTS_TO_FLOAT128_ABI are in effect, this is handled in
+   bits/stdio-ldbl.h.  */
+#include <bits/floatn.h>
+#if !__GLIBC_USE (DEPRECATED_SCANF) && !defined __LDBL_COMPAT \
+    && __LDOUBLE_REDIRECTS_TO_FLOAT128_ABI == 0
+# ifdef __REDIRECT
+extern int __REDIRECT (fscanf, (FILE *__restrict __stream,
+				const char *__restrict __format, ...),
+		       __isoc99_fscanf) __wur;
+extern int __REDIRECT (scanf, (const char *__restrict __format, ...),
+		       __isoc99_scanf) __wur;
+extern int __REDIRECT_NTH (sscanf, (const char *__restrict __s,
+				    const char *__restrict __format, ...),
+			   __isoc99_sscanf);
+# else
+extern int __isoc99_fscanf (FILE *__restrict __stream,
+			    const char *__restrict __format, ...) __wur;
+extern int __isoc99_scanf (const char *__restrict __format, ...) __wur;
+extern int __isoc99_sscanf (const char *__restrict __s,
+			    const char *__restrict __format, ...) __THROW;
+#  define fscanf __isoc99_fscanf
+#  define scanf __isoc99_scanf
+#  define sscanf __isoc99_sscanf
+# endif
+#endif
+
+#ifdef	__USE_ISOC99
+/* Read formatted input from S into argument list ARG.
+
+   This function is a possible cancellation point and therefore not
+   marked with __THROW.  */
+extern int vfscanf (FILE *__restrict __s, const char *__restrict __format,
+		    __gnuc_va_list __arg)
+     __attribute__ ((__format__ (__scanf__, 2, 0))) __wur;
+
+/* Read formatted input from stdin into argument list ARG.
+
+   This function is a possible cancellation point and therefore not
+   marked with __THROW.  */
+extern int vscanf (const char *__restrict __format, __gnuc_va_list __arg)
+     __attribute__ ((__format__ (__scanf__, 1, 0))) __wur;
+
+/* Read formatted input from S into argument list ARG.  */
+extern int vsscanf (const char *__restrict __s,
+		    const char *__restrict __format, __gnuc_va_list __arg)
+     __THROW __attribute__ ((__format__ (__scanf__, 2, 0)));
+
+/* Same redirection as above for the v*scanf family.  */
+# if !__GLIBC_USE (DEPRECATED_SCANF)
+#  if defined __REDIRECT && !defined __LDBL_COMPAT \
+      && __LDOUBLE_REDIRECTS_TO_FLOAT128_ABI == 0
+extern int __REDIRECT (vfscanf,
+		       (FILE *__restrict __s,
+			const char *__restrict __format, __gnuc_va_list __arg),
+		       __isoc99_vfscanf)
+     __attribute__ ((__format__ (__scanf__, 2, 0))) __wur;
+extern int __REDIRECT (vscanf, (const char *__restrict __format,
+				__gnuc_va_list __arg), __isoc99_vscanf)
+     __attribute__ ((__format__ (__scanf__, 1, 0))) __wur;
+extern int __REDIRECT_NTH (vsscanf,
+			   (const char *__restrict __s,
+			    const char *__restrict __format,
+			    __gnuc_va_list __arg), __isoc99_vsscanf)
+     __attribute__ ((__format__ (__scanf__, 2, 0)));
+#  elif !defined __REDIRECT
+extern int __isoc99_vfscanf (FILE *__restrict __s,
+			     const char *__restrict __format,
+			     __gnuc_va_list __arg) __wur;
+extern int __isoc99_vscanf (const char *__restrict __format,
+			    __gnuc_va_list __arg) __wur;
+extern int __isoc99_vsscanf (const char *__restrict __s,
+			     const char *__restrict __format,
+			     __gnuc_va_list __arg) __THROW;
+#   define vfscanf __isoc99_vfscanf
+#   define vscanf __isoc99_vscanf
+#   define vsscanf __isoc99_vsscanf
+#  endif
+# endif
+#endif /* Use ISO C9x.  */
+
+
+/* Read a character from STREAM.
+
+   These functions are possible cancellation points and therefore not
+   marked with __THROW.  */
+extern int fgetc (FILE *__stream);
+extern int getc (FILE *__stream);
+
+/* Read a character from stdin.
+
+   This function is a possible cancellation point and therefore not
+   marked with __THROW.  */
+extern int getchar (void);
+
+#ifdef __USE_POSIX199506
+/* These are defined in POSIX.1:1996.
+
+   These functions are possible cancellation points and therefore not
+   marked with __THROW.  */
+extern int getc_unlocked (FILE *__stream);
+extern int getchar_unlocked (void);
+#endif /* Use POSIX.  */
+
+#ifdef __USE_MISC
+/* Faster version when locking is not necessary.
+
+   This function is not part of POSIX and therefore no official
+   cancellation point.  But due to similarity with an POSIX interface
+   or due to the implementation it is a cancellation point and
+   therefore not marked with __THROW.  */
+extern int fgetc_unlocked (FILE *__stream);
+#endif /* Use MISC.  */
+
+
+/* Write a character to STREAM.
+
+   These functions are possible cancellation points and therefore not
+   marked with __THROW.
+
+   These functions is a possible cancellation point and therefore not
+   marked with __THROW.  */
+extern int fputc (int __c, FILE *__stream);
+extern int putc (int __c, FILE *__stream);
+
+/* Write a character to stdout.
+
+   This function is a possible cancellation point and therefore not
+   marked with __THROW.  */
+extern int putchar (int __c);
+
+#ifdef __USE_MISC
+/* Faster version when locking is not necessary.
+
+   This function is not part of POSIX and therefore no official
+   cancellation point.  But due to similarity with an POSIX interface
+   or due to the implementation it is a cancellation point and
+   therefore not marked with __THROW.  */
+extern int fputc_unlocked (int __c, FILE *__stream);
+#endif /* Use MISC.  */
+
+#ifdef __USE_POSIX199506
+/* These are defined in POSIX.1:1996.
+
+   These functions are possible cancellation points and therefore not
+   marked with __THROW.  */
+extern int putc_unlocked (int __c, FILE *__stream);
+extern int putchar_unlocked (int __c);
+#endif /* Use POSIX.  */
+
+
+#if defined __USE_MISC \
+    || (defined __USE_XOPEN && !defined __USE_XOPEN2K)
+/* Get a word (int) from STREAM.  */
+extern int getw (FILE *__stream);
+
+/* Write a word (int) to STREAM.  */
+extern int putw (int __w, FILE *__stream);
+#endif
+
+
+/* Get a newline-terminated string of finite length from STREAM.
+
+   This function is a possible cancellation point and therefore not
+   marked with __THROW.  */
+extern char *fgets (char *__restrict __s, int __n, FILE *__restrict __stream)
+     __wur __fortified_attr_access (__write_only__, 1, 2);
+
+#if __GLIBC_USE (DEPRECATED_GETS)
+/* Get a newline-terminated string from stdin, removing the newline.
+
+   This function is impossible to use safely.  It has been officially
+   removed from ISO C11 and ISO C++14, and we have also removed it
+   from the _GNU_SOURCE feature list.  It remains available when
+   explicitly using an old ISO C, Unix, or POSIX standard.
+
+   This function is a possible cancellation point and therefore not
+   marked with __THROW.  */
+extern char *gets (char *__s) __wur __attribute_deprecated__;
+#endif
+
+#ifdef __USE_GNU
+/* This function does the same as `fgets' but does not lock the stream.
+
+   This function is not part of POSIX and therefore no official
+   cancellation point.  But due to similarity with an POSIX interface
+   or due to the implementation it is a cancellation point and
+   therefore not marked with __THROW.  */
+extern char *fgets_unlocked (char *__restrict __s, int __n,
+			     FILE *__restrict __stream) __wur
+    __fortified_attr_access (__write_only__, 1, 2);
+#endif
+
+
+#if defined __USE_XOPEN2K8 || __GLIBC_USE (LIB_EXT2)
+/* Read up to (and including) a DELIMITER from STREAM into *LINEPTR
+   (and null-terminate it). *LINEPTR is a pointer returned from malloc (or
+   NULL), pointing to *N characters of space.  It is realloc'd as
+   necessary.  Returns the number of characters read (not including the
+   null terminator), or -1 on error or EOF.
+
+   These functions are not part of POSIX and therefore no official
+   cancellation point.  But due to similarity with an POSIX interface
+   or due to the implementation they are cancellation points and
+   therefore not marked with __THROW.  */
+extern __ssize_t __getdelim (char **__restrict __lineptr,
+                             size_t *__restrict __n, int __delimiter,
+                             FILE *__restrict __stream) __wur;
+extern __ssize_t getdelim (char **__restrict __lineptr,
+                           size_t *__restrict __n, int __delimiter,
+                           FILE *__restrict __stream) __wur;
+
+/* Like `getdelim', but reads up to a newline.
+
+   This function is not part of POSIX and therefore no official
+   cancellation point.  But due to similarity with an POSIX interface
+   or due to the implementation it is a cancellation point and
+   therefore not marked with __THROW.  */
+extern __ssize_t getline (char **__restrict __lineptr,
+                          size_t *__restrict __n,
+                          FILE *__restrict __stream) __wur;
+#endif
+
+
+/* Write a string to STREAM.
+
+   This function is a possible cancellation point and therefore not
+   marked with __THROW.  */
+extern int fputs (const char *__restrict __s, FILE *__restrict __stream);
+
+/* Write a string, followed by a newline, to stdout.
+
+   This function is a possible cancellation point and therefore not
+   marked with __THROW.  */
+extern int puts (const char *__s);
+
+
+/* Push a character back onto the input buffer of STREAM.
+
+   This function is a possible cancellation point and therefore not
+   marked with __THROW.  */
+extern int ungetc (int __c, FILE *__stream);
+
+
+/* Read chunks of generic data from STREAM.
+
+   This function is a possible cancellation point and therefore not
+   marked with __THROW.  */
+extern size_t fread (void *__restrict __ptr, size_t __size,
+		     size_t __n, FILE *__restrict __stream) __wur;
+/* Write chunks of generic data to STREAM.
+
+   This function is a possible cancellation point and therefore not
+   marked with __THROW.  */
+extern size_t fwrite (const void *__restrict __ptr, size_t __size,
+		      size_t __n, FILE *__restrict __s);
+
+#ifdef __USE_GNU
+/* This function does the same as `fputs' but does not lock the stream.
+
+   This function is not part of POSIX and therefore no official
+   cancellation point.  But due to similarity with an POSIX interface
+   or due to the implementation it is a cancellation point and
+   therefore not marked with __THROW.  */
+extern int fputs_unlocked (const char *__restrict __s,
+			   FILE *__restrict __stream);
+#endif
+
+#ifdef __USE_MISC
+/* Faster versions when locking is not necessary.
+
+   These functions are not part of POSIX and therefore no official
+   cancellation point.  But due to similarity with an POSIX interface
+   or due to the implementation they are cancellation points and
+   therefore not marked with __THROW.  */
+extern size_t fread_unlocked (void *__restrict __ptr, size_t __size,
+			      size_t __n, FILE *__restrict __stream) __wur;
+extern size_t fwrite_unlocked (const void *__restrict __ptr, size_t __size,
+			       size_t __n, FILE *__restrict __stream);
+#endif
+
+
+/* Seek to a certain position on STREAM.
+
+   This function is a possible cancellation point and therefore not
+   marked with __THROW.  */
+extern int fseek (FILE *__stream, long int __off, int __whence);
+/* Return the current position of STREAM.
+
+   This function is a possible cancellation point and therefore not
+   marked with __THROW.  */
+extern long int ftell (FILE *__stream) __wur;
+/* Rewind to the beginning of STREAM.
+
+   This function is a possible cancellation point and therefore not
+   marked with __THROW.  */
+extern void rewind (FILE *__stream);
+
+/* The Single Unix Specification, Version 2, specifies an alternative,
+   more adequate interface for the two functions above which deal with
+   file offset.  `long int' is not the right type.  These definitions
+   are originally defined in the Large File Support API.  */
+
+#if defined __USE_LARGEFILE || defined __USE_XOPEN2K
+# ifndef __USE_FILE_OFFSET64
+/* Seek to a certain position on STREAM.
+
+   This function is a possible cancellation point and therefore not
+   marked with __THROW.  */
+extern int fseeko (FILE *__stream, __off_t __off, int __whence);
+/* Return the current position of STREAM.
+
+   This function is a possible cancellation point and therefore not
+   marked with __THROW.  */
+extern __off_t ftello (FILE *__stream) __wur;
+# else
+#  ifdef __REDIRECT
+extern int __REDIRECT (fseeko,
+		       (FILE *__stream, __off64_t __off, int __whence),
+		       fseeko64);
+extern __off64_t __REDIRECT (ftello, (FILE *__stream), ftello64);
+#  else
+#   define fseeko fseeko64
+#   define ftello ftello64
+#  endif
+# endif
+#endif
+
+#ifndef __USE_FILE_OFFSET64
+/* Get STREAM's position.
+
+   This function is a possible cancellation point and therefore not
+   marked with __THROW.  */
+extern int fgetpos (FILE *__restrict __stream, fpos_t *__restrict __pos);
+/* Set STREAM's position.
+
+   This function is a possible cancellation point and therefore not
+   marked with __THROW.  */
+extern int fsetpos (FILE *__stream, const fpos_t *__pos);
+#else
+# ifdef __REDIRECT
+extern int __REDIRECT (fgetpos, (FILE *__restrict __stream,
+				 fpos_t *__restrict __pos), fgetpos64);
+extern int __REDIRECT (fsetpos,
+		       (FILE *__stream, const fpos_t *__pos), fsetpos64);
+# else
+#  define fgetpos fgetpos64
+#  define fsetpos fsetpos64
+# endif
+#endif
+
+#ifdef __USE_LARGEFILE64
+extern int fseeko64 (FILE *__stream, __off64_t __off, int __whence);
+extern __off64_t ftello64 (FILE *__stream) __wur;
+extern int fgetpos64 (FILE *__restrict __stream, fpos64_t *__restrict __pos);
+extern int fsetpos64 (FILE *__stream, const fpos64_t *__pos);
+#endif
+
+/* Clear the error and EOF indicators for STREAM.  */
+extern void clearerr (FILE *__stream) __THROW;
+/* Return the EOF indicator for STREAM.  */
+extern int feof (FILE *__stream) __THROW __wur;
+/* Return the error indicator for STREAM.  */
+extern int ferror (FILE *__stream) __THROW __wur;
+
+#ifdef __USE_MISC
+/* Faster versions when locking is not required.  */
+extern void clearerr_unlocked (FILE *__stream) __THROW;
+extern int feof_unlocked (FILE *__stream) __THROW __wur;
+extern int ferror_unlocked (FILE *__stream) __THROW __wur;
+#endif
+
+
+/* Print a message describing the meaning of the value of errno.
+
+   This function is a possible cancellation point and therefore not
+   marked with __THROW.  */
+extern void perror (const char *__s);
+
+
+#ifdef	__USE_POSIX
+/* Return the system file descriptor for STREAM.  */
+extern int fileno (FILE *__stream) __THROW __wur;
+#endif /* Use POSIX.  */
+
+#ifdef __USE_MISC
+/* Faster version when locking is not required.  */
+extern int fileno_unlocked (FILE *__stream) __THROW __wur;
+#endif
+
+
+#ifdef __USE_POSIX2
+/* Close a stream opened by popen and return the status of its child.
+
+   This function is a possible cancellation point and therefore not
+   marked with __THROW.  */
+extern int pclose (FILE *__stream);
+
+/* Create a new stream connected to a pipe running the given command.
+
+   This function is a possible cancellation point and therefore not
+   marked with __THROW.  */
+extern FILE *popen (const char *__command, const char *__modes)
+  __attribute_malloc__ __attr_dealloc (pclose, 1) __wur;
+
+#endif
+
+
+#ifdef	__USE_POSIX
+/* Return the name of the controlling terminal.  */
+extern char *ctermid (char *__s) __THROW
+  __attr_access ((__write_only__, 1));
+#endif /* Use POSIX.  */
+
+
+#if (defined __USE_XOPEN && !defined __USE_XOPEN2K) || defined __USE_GNU
+/* Return the name of the current user.  */
+extern char *cuserid (char *__s)
+  __attr_access ((__write_only__, 1));
+#endif /* Use X/Open, but not issue 6.  */
+
+
+#ifdef	__USE_GNU
+struct obstack;			/* See <obstack.h>.  */
+
+/* Write formatted output to an obstack.  */
+extern int obstack_printf (struct obstack *__restrict __obstack,
+			   const char *__restrict __format, ...)
+     __THROWNL __attribute__ ((__format__ (__printf__, 2, 3)));
+extern int obstack_vprintf (struct obstack *__restrict __obstack,
+			    const char *__restrict __format,
+			    __gnuc_va_list __args)
+     __THROWNL __attribute__ ((__format__ (__printf__, 2, 0)));
+#endif /* Use GNU.  */
+
+
+#ifdef __USE_POSIX199506
+/* These are defined in POSIX.1:1996.  */
+
+/* Acquire ownership of STREAM.  */
+extern void flockfile (FILE *__stream) __THROW;
+
+/* Try to acquire ownership of STREAM but do not block if it is not
+   possible.  */
+extern int ftrylockfile (FILE *__stream) __THROW __wur;
+
+/* Relinquish the ownership granted for STREAM.  */
+extern void funlockfile (FILE *__stream) __THROW;
+#endif /* POSIX */
+
+#if defined __USE_XOPEN && !defined __USE_XOPEN2K && !defined __USE_GNU
+/*  X/Open Issues 1-5 required getopt to be declared in this
+   header.  It was removed in Issue 6.  GNU follows Issue 6.  */
+# include <bits/getopt_posix.h>
+#endif
+
+/* Slow-path routines used by the optimized inline functions in
+   bits/stdio.h.  */
+extern int __uflow (FILE *);
+extern int __overflow (FILE *, int);
+
+#if __USE_FORTIFY_LEVEL > 0 && defined __fortify_function
+/* Declare all functions from bits/stdio2-decl.h first.  */
+# include <bits/stdio2-decl.h>
+#endif
+
+/* The following headers provide asm redirections.  These redirections must
+   appear before the first usage of these functions, e.g. in bits/stdio.h.  */
+#if defined __LDBL_COMPAT || __LDOUBLE_REDIRECTS_TO_FLOAT128_ABI == 1
+# include <bits/stdio-ldbl.h>
+#endif
+
+/* If we are compiling with optimizing read this file.  It contains
+   several optimizing inline functions and macros.  */
+#ifdef __USE_EXTERN_INLINES
+# include <bits/stdio.h>
+#endif
+#if __USE_FORTIFY_LEVEL > 0 && defined __fortify_function
+/* Now include the function definitions and redirects too.  */
+# include <bits/stdio2.h>
+#endif
+
+__END_DECLS
+
+#endif /* <stdio.h> included.  */
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@stdlib.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@stdlib.h
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@stdlib.h
@@ -0,0 +1,1037 @@
+/* Copyright (C) 1991-2022 Free Software Foundation, Inc.
+   Copyright The GNU Toolchain Authors.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+/*
+ *	ISO C99 Standard: 7.20 General utilities	<stdlib.h>
+ */
+
+#ifndef	_STDLIB_H
+
+#define __GLIBC_INTERNAL_STARTING_HEADER_IMPLEMENTATION
+#include <bits/libc-header-start.h>
+
+/* Get size_t, wchar_t and NULL from <stddef.h>.  */
+#define __need_size_t
+#define __need_wchar_t
+#define __need_NULL
+#include <stddef.h>
+
+__BEGIN_DECLS
+
+#define	_STDLIB_H	1
+
+#if (defined __USE_XOPEN || defined __USE_XOPEN2K8) && !defined _SYS_WAIT_H
+/* XPG requires a few symbols from <sys/wait.h> being defined.  */
+# include <bits/waitflags.h>
+# include <bits/waitstatus.h>
+
+/* Define the macros <sys/wait.h> also would define this way.  */
+# define WEXITSTATUS(status)	__WEXITSTATUS (status)
+# define WTERMSIG(status)	__WTERMSIG (status)
+# define WSTOPSIG(status)	__WSTOPSIG (status)
+# define WIFEXITED(status)	__WIFEXITED (status)
+# define WIFSIGNALED(status)	__WIFSIGNALED (status)
+# define WIFSTOPPED(status)	__WIFSTOPPED (status)
+# ifdef __WIFCONTINUED
+#  define WIFCONTINUED(status)	__WIFCONTINUED (status)
+# endif
+#endif	/* X/Open or XPG7 and <sys/wait.h> not included.  */
+
+/* _FloatN API tests for enablement.  */
+#include <bits/floatn.h>
+
+/* Returned by `div'.  */
+typedef struct
+  {
+    int quot;			/* Quotient.  */
+    int rem;			/* Remainder.  */
+  } div_t;
+
+/* Returned by `ldiv'.  */
+#ifndef __ldiv_t_defined
+typedef struct
+  {
+    long int quot;		/* Quotient.  */
+    long int rem;		/* Remainder.  */
+  } ldiv_t;
+# define __ldiv_t_defined	1
+#endif
+
+#if defined __USE_ISOC99 && !defined __lldiv_t_defined
+/* Returned by `lldiv'.  */
+__extension__ typedef struct
+  {
+    long long int quot;		/* Quotient.  */
+    long long int rem;		/* Remainder.  */
+  } lldiv_t;
+# define __lldiv_t_defined	1
+#endif
+
+
+/* The largest number rand will return (same as INT_MAX).  */
+#define	RAND_MAX	2147483647
+
+
+/* We define these the same for all machines.
+   Changes from this to the outside world should be done in `_exit'.  */
+#define	EXIT_FAILURE	1	/* Failing exit status.  */
+#define	EXIT_SUCCESS	0	/* Successful exit status.  */
+
+
+/* Maximum length of a multibyte character in the current locale.  */
+#define	MB_CUR_MAX	(__ctype_get_mb_cur_max ())
+extern size_t __ctype_get_mb_cur_max (void) __THROW __wur;
+
+
+/* Convert a string to a floating-point number.  */
+extern double atof (const char *__nptr)
+     __THROW __attribute_pure__ __nonnull ((1)) __wur;
+/* Convert a string to an integer.  */
+extern int atoi (const char *__nptr)
+     __THROW __attribute_pure__ __nonnull ((1)) __wur;
+/* Convert a string to a long integer.  */
+extern long int atol (const char *__nptr)
+     __THROW __attribute_pure__ __nonnull ((1)) __wur;
+
+#ifdef __USE_ISOC99
+/* Convert a string to a long long integer.  */
+__extension__ extern long long int atoll (const char *__nptr)
+     __THROW __attribute_pure__ __nonnull ((1)) __wur;
+#endif
+
+/* Convert a string to a floating-point number.  */
+extern double strtod (const char *__restrict __nptr,
+		      char **__restrict __endptr)
+     __THROW __nonnull ((1));
+
+#ifdef	__USE_ISOC99
+/* Likewise for `float' and `long double' sizes of floating-point numbers.  */
+extern float strtof (const char *__restrict __nptr,
+		     char **__restrict __endptr) __THROW __nonnull ((1));
+
+extern long double strtold (const char *__restrict __nptr,
+			    char **__restrict __endptr)
+     __THROW __nonnull ((1));
+#endif
+
+/* Likewise for '_FloatN' and '_FloatNx'.  */
+
+#if __HAVE_FLOAT16 && __GLIBC_USE (IEC_60559_TYPES_EXT)
+extern _Float16 strtof16 (const char *__restrict __nptr,
+			  char **__restrict __endptr)
+     __THROW __nonnull ((1));
+#endif
+
+#if __HAVE_FLOAT32 && __GLIBC_USE (IEC_60559_TYPES_EXT)
+extern _Float32 strtof32 (const char *__restrict __nptr,
+			  char **__restrict __endptr)
+     __THROW __nonnull ((1));
+#endif
+
+#if __HAVE_FLOAT64 && __GLIBC_USE (IEC_60559_TYPES_EXT)
+extern _Float64 strtof64 (const char *__restrict __nptr,
+			  char **__restrict __endptr)
+     __THROW __nonnull ((1));
+#endif
+
+#if __HAVE_FLOAT128 && __GLIBC_USE (IEC_60559_TYPES_EXT)
+extern _Float128 strtof128 (const char *__restrict __nptr,
+			    char **__restrict __endptr)
+     __THROW __nonnull ((1));
+#endif
+
+#if __HAVE_FLOAT32X && __GLIBC_USE (IEC_60559_TYPES_EXT)
+extern _Float32x strtof32x (const char *__restrict __nptr,
+			    char **__restrict __endptr)
+     __THROW __nonnull ((1));
+#endif
+
+#if __HAVE_FLOAT64X && __GLIBC_USE (IEC_60559_TYPES_EXT)
+extern _Float64x strtof64x (const char *__restrict __nptr,
+			    char **__restrict __endptr)
+     __THROW __nonnull ((1));
+#endif
+
+#if __HAVE_FLOAT128X && __GLIBC_USE (IEC_60559_TYPES_EXT)
+extern _Float128x strtof128x (const char *__restrict __nptr,
+			      char **__restrict __endptr)
+     __THROW __nonnull ((1));
+#endif
+
+/* Convert a string to a long integer.  */
+extern long int strtol (const char *__restrict __nptr,
+			char **__restrict __endptr, int __base)
+     __THROW __nonnull ((1));
+/* Convert a string to an unsigned long integer.  */
+extern unsigned long int strtoul (const char *__restrict __nptr,
+				  char **__restrict __endptr, int __base)
+     __THROW __nonnull ((1));
+
+#ifdef __USE_MISC
+/* Convert a string to a quadword integer.  */
+__extension__
+extern long long int strtoq (const char *__restrict __nptr,
+			     char **__restrict __endptr, int __base)
+     __THROW __nonnull ((1));
+/* Convert a string to an unsigned quadword integer.  */
+__extension__
+extern unsigned long long int strtouq (const char *__restrict __nptr,
+				       char **__restrict __endptr, int __base)
+     __THROW __nonnull ((1));
+#endif /* Use misc.  */
+
+#ifdef __USE_ISOC99
+/* Convert a string to a quadword integer.  */
+__extension__
+extern long long int strtoll (const char *__restrict __nptr,
+			      char **__restrict __endptr, int __base)
+     __THROW __nonnull ((1));
+/* Convert a string to an unsigned quadword integer.  */
+__extension__
+extern unsigned long long int strtoull (const char *__restrict __nptr,
+					char **__restrict __endptr, int __base)
+     __THROW __nonnull ((1));
+#endif /* ISO C99 or use MISC.  */
+
+/* Convert a floating-point number to a string.  */
+#if __GLIBC_USE (IEC_60559_BFP_EXT_C2X)
+extern int strfromd (char *__dest, size_t __size, const char *__format,
+		     double __f)
+     __THROW __nonnull ((3));
+
+extern int strfromf (char *__dest, size_t __size, const char *__format,
+		     float __f)
+     __THROW __nonnull ((3));
+
+extern int strfroml (char *__dest, size_t __size, const char *__format,
+		     long double __f)
+     __THROW __nonnull ((3));
+#endif
+
+#if __HAVE_FLOAT16 && __GLIBC_USE (IEC_60559_TYPES_EXT)
+extern int strfromf16 (char *__dest, size_t __size, const char * __format,
+		       _Float16 __f)
+     __THROW __nonnull ((3));
+#endif
+
+#if __HAVE_FLOAT32 && __GLIBC_USE (IEC_60559_TYPES_EXT)
+extern int strfromf32 (char *__dest, size_t __size, const char * __format,
+		       _Float32 __f)
+     __THROW __nonnull ((3));
+#endif
+
+#if __HAVE_FLOAT64 && __GLIBC_USE (IEC_60559_TYPES_EXT)
+extern int strfromf64 (char *__dest, size_t __size, const char * __format,
+		       _Float64 __f)
+     __THROW __nonnull ((3));
+#endif
+
+#if __HAVE_FLOAT128 && __GLIBC_USE (IEC_60559_TYPES_EXT)
+extern int strfromf128 (char *__dest, size_t __size, const char * __format,
+			_Float128 __f)
+     __THROW __nonnull ((3));
+#endif
+
+#if __HAVE_FLOAT32X && __GLIBC_USE (IEC_60559_TYPES_EXT)
+extern int strfromf32x (char *__dest, size_t __size, const char * __format,
+			_Float32x __f)
+     __THROW __nonnull ((3));
+#endif
+
+#if __HAVE_FLOAT64X && __GLIBC_USE (IEC_60559_TYPES_EXT)
+extern int strfromf64x (char *__dest, size_t __size, const char * __format,
+			_Float64x __f)
+     __THROW __nonnull ((3));
+#endif
+
+#if __HAVE_FLOAT128X && __GLIBC_USE (IEC_60559_TYPES_EXT)
+extern int strfromf128x (char *__dest, size_t __size, const char * __format,
+			 _Float128x __f)
+     __THROW __nonnull ((3));
+#endif
+
+
+#ifdef __USE_GNU
+/* Parallel versions of the functions above which take the locale to
+   use as an additional parameter.  These are GNU extensions inspired
+   by the POSIX.1-2008 extended locale API.  */
+# include <bits/types/locale_t.h>
+
+extern long int strtol_l (const char *__restrict __nptr,
+			  char **__restrict __endptr, int __base,
+			  locale_t __loc) __THROW __nonnull ((1, 4));
+
+extern unsigned long int strtoul_l (const char *__restrict __nptr,
+				    char **__restrict __endptr,
+				    int __base, locale_t __loc)
+     __THROW __nonnull ((1, 4));
+
+__extension__
+extern long long int strtoll_l (const char *__restrict __nptr,
+				char **__restrict __endptr, int __base,
+				locale_t __loc)
+     __THROW __nonnull ((1, 4));
+
+__extension__
+extern unsigned long long int strtoull_l (const char *__restrict __nptr,
+					  char **__restrict __endptr,
+					  int __base, locale_t __loc)
+     __THROW __nonnull ((1, 4));
+
+extern double strtod_l (const char *__restrict __nptr,
+			char **__restrict __endptr, locale_t __loc)
+     __THROW __nonnull ((1, 3));
+
+extern float strtof_l (const char *__restrict __nptr,
+		       char **__restrict __endptr, locale_t __loc)
+     __THROW __nonnull ((1, 3));
+
+extern long double strtold_l (const char *__restrict __nptr,
+			      char **__restrict __endptr,
+			      locale_t __loc)
+     __THROW __nonnull ((1, 3));
+
+# if __HAVE_FLOAT16
+extern _Float16 strtof16_l (const char *__restrict __nptr,
+			    char **__restrict __endptr,
+			    locale_t __loc)
+     __THROW __nonnull ((1, 3));
+# endif
+
+# if __HAVE_FLOAT32
+extern _Float32 strtof32_l (const char *__restrict __nptr,
+			    char **__restrict __endptr,
+			    locale_t __loc)
+     __THROW __nonnull ((1, 3));
+# endif
+
+# if __HAVE_FLOAT64
+extern _Float64 strtof64_l (const char *__restrict __nptr,
+			    char **__restrict __endptr,
+			    locale_t __loc)
+     __THROW __nonnull ((1, 3));
+# endif
+
+# if __HAVE_FLOAT128
+extern _Float128 strtof128_l (const char *__restrict __nptr,
+			      char **__restrict __endptr,
+			      locale_t __loc)
+     __THROW __nonnull ((1, 3));
+# endif
+
+# if __HAVE_FLOAT32X
+extern _Float32x strtof32x_l (const char *__restrict __nptr,
+			      char **__restrict __endptr,
+			      locale_t __loc)
+     __THROW __nonnull ((1, 3));
+# endif
+
+# if __HAVE_FLOAT64X
+extern _Float64x strtof64x_l (const char *__restrict __nptr,
+			      char **__restrict __endptr,
+			      locale_t __loc)
+     __THROW __nonnull ((1, 3));
+# endif
+
+# if __HAVE_FLOAT128X
+extern _Float128x strtof128x_l (const char *__restrict __nptr,
+				char **__restrict __endptr,
+				locale_t __loc)
+     __THROW __nonnull ((1, 3));
+# endif
+#endif /* GNU */
+
+
+#ifdef __USE_EXTERN_INLINES
+__extern_inline int
+__NTH (atoi (const char *__nptr))
+{
+  return (int) strtol (__nptr, (char **) NULL, 10);
+}
+__extern_inline long int
+__NTH (atol (const char *__nptr))
+{
+  return strtol (__nptr, (char **) NULL, 10);
+}
+
+# ifdef __USE_ISOC99
+__extension__ __extern_inline long long int
+__NTH (atoll (const char *__nptr))
+{
+  return strtoll (__nptr, (char **) NULL, 10);
+}
+# endif
+#endif /* Optimizing and Inlining.  */
+
+
+#if defined __USE_MISC || defined __USE_XOPEN_EXTENDED
+/* Convert N to base 64 using the digits "./0-9A-Za-z", least-significant
+   digit first.  Returns a pointer to static storage overwritten by the
+   next call.  */
+extern char *l64a (long int __n) __THROW __wur;
+
+/* Read a number from a string S in base 64 as above.  */
+extern long int a64l (const char *__s)
+     __THROW __attribute_pure__ __nonnull ((1)) __wur;
+
+#endif	/* Use misc || extended X/Open.  */
+
+#if defined __USE_MISC || defined __USE_XOPEN_EXTENDED
+# include <sys/types.h>	/* we need int32_t... */
+
+/* These are the functions that actually do things.  The `random', `srandom',
+   `initstate' and `setstate' functions are those from BSD Unices.
+   The `rand' and `srand' functions are required by the ANSI standard.
+   We provide both interfaces to the same random number generator.  */
+/* Return a random long integer between 0 and 2^31-1 inclusive.  */
+extern long int random (void) __THROW;
+
+/* Seed the random number generator with the given number.  */
+extern void srandom (unsigned int __seed) __THROW;
+
+/* Initialize the random number generator to use state buffer STATEBUF,
+   of length STATELEN, and seed it with SEED.  Optimal lengths are 8, 16,
+   32, 64, 128 and 256, the bigger the better; values less than 8 will
+   cause an error and values greater than 256 will be rounded down.  */
+extern char *initstate (unsigned int __seed, char *__statebuf,
+			size_t __statelen) __THROW __nonnull ((2));
+
+/* Switch the random number generator to state buffer STATEBUF,
+   which should have been previously initialized by `initstate'.  */
+extern char *setstate (char *__statebuf) __THROW __nonnull ((1));
+
+
+# ifdef __USE_MISC
+/* Reentrant versions of the `random' family of functions.
+   These functions all use the following data structure to contain
+   state, rather than global state variables.  */
+
+struct random_data
+  {
+    int32_t *fptr;		/* Front pointer.  */
+    int32_t *rptr;		/* Rear pointer.  */
+    int32_t *state;		/* Array of state values.  */
+    int rand_type;		/* Type of random number generator.  */
+    int rand_deg;		/* Degree of random number generator.  */
+    int rand_sep;		/* Distance between front and rear.  */
+    int32_t *end_ptr;		/* Pointer behind state table.  */
+  };
+
+extern int random_r (struct random_data *__restrict __buf,
+		     int32_t *__restrict __result) __THROW __nonnull ((1, 2));
+
+extern int srandom_r (unsigned int __seed, struct random_data *__buf)
+     __THROW __nonnull ((2));
+
+extern int initstate_r (unsigned int __seed, char *__restrict __statebuf,
+			size_t __statelen,
+			struct random_data *__restrict __buf)
+     __THROW __nonnull ((2, 4));
+
+extern int setstate_r (char *__restrict __statebuf,
+		       struct random_data *__restrict __buf)
+     __THROW __nonnull ((1, 2));
+# endif	/* Use misc.  */
+#endif	/* Use extended X/Open || misc. */
+
+
+/* Return a random integer between 0 and RAND_MAX inclusive.  */
+extern int rand (void) __THROW;
+/* Seed the random number generator with the given number.  */
+extern void srand (unsigned int __seed) __THROW;
+
+#ifdef __USE_POSIX199506
+/* Reentrant interface according to POSIX.1.  */
+extern int rand_r (unsigned int *__seed) __THROW;
+#endif
+
+
+#if defined __USE_MISC || defined __USE_XOPEN
+/* System V style 48-bit random number generator functions.  */
+
+/* Return non-negative, double-precision floating-point value in [0.0,1.0).  */
+extern double drand48 (void) __THROW;
+extern double erand48 (unsigned short int __xsubi[3]) __THROW __nonnull ((1));
+
+/* Return non-negative, long integer in [0,2^31).  */
+extern long int lrand48 (void) __THROW;
+extern long int nrand48 (unsigned short int __xsubi[3])
+     __THROW __nonnull ((1));
+
+/* Return signed, long integers in [-2^31,2^31).  */
+extern long int mrand48 (void) __THROW;
+extern long int jrand48 (unsigned short int __xsubi[3])
+     __THROW __nonnull ((1));
+
+/* Seed random number generator.  */
+extern void srand48 (long int __seedval) __THROW;
+extern unsigned short int *seed48 (unsigned short int __seed16v[3])
+     __THROW __nonnull ((1));
+extern void lcong48 (unsigned short int __param[7]) __THROW __nonnull ((1));
+
+# ifdef __USE_MISC
+/* Data structure for communication with thread safe versions.  This
+   type is to be regarded as opaque.  It's only exported because users
+   have to allocate objects of this type.  */
+struct drand48_data
+  {
+    unsigned short int __x[3];	/* Current state.  */
+    unsigned short int __old_x[3]; /* Old state.  */
+    unsigned short int __c;	/* Additive const. in congruential formula.  */
+    unsigned short int __init;	/* Flag for initializing.  */
+    __extension__ unsigned long long int __a;	/* Factor in congruential
+						   formula.  */
+  };
+
+/* Return non-negative, double-precision floating-point value in [0.0,1.0).  */
+extern int drand48_r (struct drand48_data *__restrict __buffer,
+		      double *__restrict __result) __THROW __nonnull ((1, 2));
+extern int erand48_r (unsigned short int __xsubi[3],
+		      struct drand48_data *__restrict __buffer,
+		      double *__restrict __result) __THROW __nonnull ((1, 2));
+
+/* Return non-negative, long integer in [0,2^31).  */
+extern int lrand48_r (struct drand48_data *__restrict __buffer,
+		      long int *__restrict __result)
+     __THROW __nonnull ((1, 2));
+extern int nrand48_r (unsigned short int __xsubi[3],
+		      struct drand48_data *__restrict __buffer,
+		      long int *__restrict __result)
+     __THROW __nonnull ((1, 2));
+
+/* Return signed, long integers in [-2^31,2^31).  */
+extern int mrand48_r (struct drand48_data *__restrict __buffer,
+		      long int *__restrict __result)
+     __THROW __nonnull ((1, 2));
+extern int jrand48_r (unsigned short int __xsubi[3],
+		      struct drand48_data *__restrict __buffer,
+		      long int *__restrict __result)
+     __THROW __nonnull ((1, 2));
+
+/* Seed random number generator.  */
+extern int srand48_r (long int __seedval, struct drand48_data *__buffer)
+     __THROW __nonnull ((2));
+
+extern int seed48_r (unsigned short int __seed16v[3],
+		     struct drand48_data *__buffer) __THROW __nonnull ((1, 2));
+
+extern int lcong48_r (unsigned short int __param[7],
+		      struct drand48_data *__buffer)
+     __THROW __nonnull ((1, 2));
+# endif	/* Use misc.  */
+#endif	/* Use misc or X/Open.  */
+
+/* Allocate SIZE bytes of memory.  */
+extern void *malloc (size_t __size) __THROW __attribute_malloc__
+     __attribute_alloc_size__ ((1)) __wur;
+/* Allocate NMEMB elements of SIZE bytes each, all initialized to 0.  */
+extern void *calloc (size_t __nmemb, size_t __size)
+     __THROW __attribute_malloc__ __attribute_alloc_size__ ((1, 2)) __wur;
+
+/* Re-allocate the previously allocated block
+   in PTR, making the new block SIZE bytes long.  */
+/* __attribute_malloc__ is not used, because if realloc returns
+   the same pointer that was passed to it, aliasing needs to be allowed
+   between objects pointed by the old and new pointers.  */
+extern void *realloc (void *__ptr, size_t __size)
+     __THROW __attribute_warn_unused_result__ __attribute_alloc_size__ ((2));
+
+/* Free a block allocated by `malloc', `realloc' or `calloc'.  */
+extern void free (void *__ptr) __THROW;
+
+#ifdef __USE_MISC
+/* Re-allocate the previously allocated block in PTR, making the new
+   block large enough for NMEMB elements of SIZE bytes each.  */
+/* __attribute_malloc__ is not used, because if reallocarray returns
+   the same pointer that was passed to it, aliasing needs to be allowed
+   between objects pointed by the old and new pointers.  */
+extern void *reallocarray (void *__ptr, size_t __nmemb, size_t __size)
+     __THROW __attribute_warn_unused_result__
+     __attribute_alloc_size__ ((2, 3))
+    __attr_dealloc_free;
+
+/* Add reallocarray as its own deallocator.  */
+extern void *reallocarray (void *__ptr, size_t __nmemb, size_t __size)
+     __THROW __attr_dealloc (reallocarray, 1);
+#endif
+
+#ifdef __USE_MISC
+# include <alloca.h>
+#endif /* Use misc.  */
+
+#if (defined __USE_XOPEN_EXTENDED && !defined __USE_XOPEN2K) \
+    || defined __USE_MISC
+/* Allocate SIZE bytes on a page boundary.  The storage cannot be freed.  */
+extern void *valloc (size_t __size) __THROW __attribute_malloc__
+     __attribute_alloc_size__ ((1)) __wur;
+#endif
+
+#ifdef __USE_XOPEN2K
+/* Allocate memory of SIZE bytes with an alignment of ALIGNMENT.  */
+extern int posix_memalign (void **__memptr, size_t __alignment, size_t __size)
+     __THROW __nonnull ((1)) __wur;
+#endif
+
+#ifdef __USE_ISOC11
+/* ISO C variant of aligned allocation.  */
+extern void *aligned_alloc (size_t __alignment, size_t __size)
+     __THROW __attribute_malloc__ __attribute_alloc_align__ ((1))
+     __attribute_alloc_size__ ((2)) __wur;
+#endif
+
+/* Abort execution and generate a core-dump.  */
+extern void abort (void) __THROW __attribute__ ((__noreturn__));
+
+
+/* Register a function to be called when `exit' is called.  */
+extern int atexit (void (*__func) (void)) __THROW __nonnull ((1));
+
+#if defined __USE_ISOC11 || defined __USE_ISOCXX11
+/* Register a function to be called when `quick_exit' is called.  */
+# ifdef __cplusplus
+extern "C++" int at_quick_exit (void (*__func) (void))
+     __THROW __asm ("at_quick_exit") __nonnull ((1));
+# else
+extern int at_quick_exit (void (*__func) (void)) __THROW __nonnull ((1));
+# endif
+#endif
+
+#ifdef	__USE_MISC
+/* Register a function to be called with the status
+   given to `exit' and the given argument.  */
+extern int on_exit (void (*__func) (int __status, void *__arg), void *__arg)
+     __THROW __nonnull ((1));
+#endif
+
+/* Call all functions registered with `atexit' and `on_exit',
+   in the reverse of the order in which they were registered,
+   perform stdio cleanup, and terminate program execution with STATUS.  */
+extern void exit (int __status) __THROW __attribute__ ((__noreturn__));
+
+#if defined __USE_ISOC11 || defined __USE_ISOCXX11
+/* Call all functions registered with `at_quick_exit' in the reverse
+   of the order in which they were registered and terminate program
+   execution with STATUS.  */
+extern void quick_exit (int __status) __THROW __attribute__ ((__noreturn__));
+#endif
+
+#ifdef __USE_ISOC99
+/* Terminate the program with STATUS without calling any of the
+   functions registered with `atexit' or `on_exit'.  */
+extern void _Exit (int __status) __THROW __attribute__ ((__noreturn__));
+#endif
+
+
+/* Return the value of envariable NAME, or NULL if it doesn't exist.  */
+extern char *getenv (const char *__name) __THROW __nonnull ((1)) __wur;
+
+#ifdef __USE_GNU
+/* This function is similar to the above but returns NULL if the
+   programs is running with SUID or SGID enabled.  */
+extern char *secure_getenv (const char *__name)
+     __THROW __nonnull ((1)) __wur;
+#endif
+
+#if defined __USE_MISC || defined __USE_XOPEN
+/* The SVID says this is in <stdio.h>, but this seems a better place.	*/
+/* Put STRING, which is of the form "NAME=VALUE", in the environment.
+   If there is no `=', remove NAME from the environment.  */
+extern int putenv (char *__string) __THROW __nonnull ((1));
+#endif
+
+#ifdef __USE_XOPEN2K
+/* Set NAME to VALUE in the environment.
+   If REPLACE is nonzero, overwrite an existing value.  */
+extern int setenv (const char *__name, const char *__value, int __replace)
+     __THROW __nonnull ((2));
+
+/* Remove the variable NAME from the environment.  */
+extern int unsetenv (const char *__name) __THROW __nonnull ((1));
+#endif
+
+#ifdef	__USE_MISC
+/* The `clearenv' was planned to be added to POSIX.1 but probably
+   never made it.  Nevertheless the POSIX.9 standard (POSIX bindings
+   for Fortran 77) requires this function.  */
+extern int clearenv (void) __THROW;
+#endif
+
+
+#if defined __USE_MISC \
+    || (defined __USE_XOPEN_EXTENDED && !defined __USE_XOPEN2K8)
+/* Generate a unique temporary file name from TEMPLATE.
+   The last six characters of TEMPLATE must be "XXXXXX";
+   they are replaced with a string that makes the file name unique.
+   Always returns TEMPLATE, it's either a temporary file name or a null
+   string if it cannot get a unique file name.  */
+extern char *mktemp (char *__template) __THROW __nonnull ((1));
+#endif
+
+#if defined __USE_XOPEN_EXTENDED || defined __USE_XOPEN2K8
+/* Generate a unique temporary file name from TEMPLATE.
+   The last six characters of TEMPLATE must be "XXXXXX";
+   they are replaced with a string that makes the filename unique.
+   Returns a file descriptor open on the file for reading and writing,
+   or -1 if it cannot create a uniquely-named file.
+
+   This function is a possible cancellation point and therefore not
+   marked with __THROW.  */
+# ifndef __USE_FILE_OFFSET64
+extern int mkstemp (char *__template) __nonnull ((1)) __wur;
+# else
+#  ifdef __REDIRECT
+extern int __REDIRECT (mkstemp, (char *__template), mkstemp64)
+     __nonnull ((1)) __wur;
+#  else
+#   define mkstemp mkstemp64
+#  endif
+# endif
+# ifdef __USE_LARGEFILE64
+extern int mkstemp64 (char *__template) __nonnull ((1)) __wur;
+# endif
+#endif
+
+#ifdef __USE_MISC
+/* Similar to mkstemp, but the template can have a suffix after the
+   XXXXXX.  The length of the suffix is specified in the second
+   parameter.
+
+   This function is a possible cancellation point and therefore not
+   marked with __THROW.  */
+# ifndef __USE_FILE_OFFSET64
+extern int mkstemps (char *__template, int __suffixlen) __nonnull ((1)) __wur;
+# else
+#  ifdef __REDIRECT
+extern int __REDIRECT (mkstemps, (char *__template, int __suffixlen),
+		       mkstemps64) __nonnull ((1)) __wur;
+#  else
+#   define mkstemps mkstemps64
+#  endif
+# endif
+# ifdef __USE_LARGEFILE64
+extern int mkstemps64 (char *__template, int __suffixlen)
+     __nonnull ((1)) __wur;
+# endif
+#endif
+
+#ifdef __USE_XOPEN2K8
+/* Create a unique temporary directory from TEMPLATE.
+   The last six characters of TEMPLATE must be "XXXXXX";
+   they are replaced with a string that makes the directory name unique.
+   Returns TEMPLATE, or a null pointer if it cannot get a unique name.
+   The directory is created mode 700.  */
+extern char *mkdtemp (char *__template) __THROW __nonnull ((1)) __wur;
+#endif
+
+#ifdef __USE_GNU
+/* Generate a unique temporary file name from TEMPLATE similar to
+   mkstemp.  But allow the caller to pass additional flags which are
+   used in the open call to create the file..
+
+   This function is a possible cancellation point and therefore not
+   marked with __THROW.  */
+# ifndef __USE_FILE_OFFSET64
+extern int mkostemp (char *__template, int __flags) __nonnull ((1)) __wur;
+# else
+#  ifdef __REDIRECT
+extern int __REDIRECT (mkostemp, (char *__template, int __flags), mkostemp64)
+     __nonnull ((1)) __wur;
+#  else
+#   define mkostemp mkostemp64
+#  endif
+# endif
+# ifdef __USE_LARGEFILE64
+extern int mkostemp64 (char *__template, int __flags) __nonnull ((1)) __wur;
+# endif
+
+/* Similar to mkostemp, but the template can have a suffix after the
+   XXXXXX.  The length of the suffix is specified in the second
+   parameter.
+
+   This function is a possible cancellation point and therefore not
+   marked with __THROW.  */
+# ifndef __USE_FILE_OFFSET64
+extern int mkostemps (char *__template, int __suffixlen, int __flags)
+     __nonnull ((1)) __wur;
+# else
+#  ifdef __REDIRECT
+extern int __REDIRECT (mkostemps, (char *__template, int __suffixlen,
+				   int __flags), mkostemps64)
+     __nonnull ((1)) __wur;
+#  else
+#   define mkostemps mkostemps64
+#  endif
+# endif
+# ifdef __USE_LARGEFILE64
+extern int mkostemps64 (char *__template, int __suffixlen, int __flags)
+     __nonnull ((1)) __wur;
+# endif
+#endif
+
+
+/* Execute the given line as a shell command.
+
+   This function is a cancellation point and therefore not marked with
+   __THROW.  */
+extern int system (const char *__command) __wur;
+
+
+#ifdef	__USE_GNU
+/* Return a malloc'd string containing the canonical absolute name of the
+   existing named file.  */
+extern char *canonicalize_file_name (const char *__name)
+     __THROW __nonnull ((1)) __attribute_malloc__
+     __attr_dealloc_free __wur;
+#endif
+
+#if defined __USE_MISC || defined __USE_XOPEN_EXTENDED
+/* Return the canonical absolute name of file NAME.  If RESOLVED is
+   null, the result is malloc'd; otherwise, if the canonical name is
+   PATH_MAX chars or more, returns null with `errno' set to
+   ENAMETOOLONG; if the name fits in fewer than PATH_MAX chars,
+   returns the name in RESOLVED.  */
+extern char *realpath (const char *__restrict __name,
+		       char *__restrict __resolved) __THROW __wur;
+#endif
+
+
+/* Shorthand for type of comparison functions.  */
+#ifndef __COMPAR_FN_T
+# define __COMPAR_FN_T
+typedef int (*__compar_fn_t) (const void *, const void *);
+
+# ifdef	__USE_GNU
+typedef __compar_fn_t comparison_fn_t;
+# endif
+#endif
+#ifdef __USE_GNU
+typedef int (*__compar_d_fn_t) (const void *, const void *, void *);
+#endif
+
+/* Do a binary search for KEY in BASE, which consists of NMEMB elements
+   of SIZE bytes each, using COMPAR to perform the comparisons.  */
+extern void *bsearch (const void *__key, const void *__base,
+		      size_t __nmemb, size_t __size, __compar_fn_t __compar)
+     __nonnull ((1, 2, 5)) __wur;
+
+#ifdef __USE_EXTERN_INLINES
+# include <bits/stdlib-bsearch.h>
+#endif
+
+/* Sort NMEMB elements of BASE, of SIZE bytes each,
+   using COMPAR to perform the comparisons.  */
+extern void qsort (void *__base, size_t __nmemb, size_t __size,
+		   __compar_fn_t __compar) __nonnull ((1, 4));
+#ifdef __USE_GNU
+extern void qsort_r (void *__base, size_t __nmemb, size_t __size,
+		     __compar_d_fn_t __compar, void *__arg)
+  __nonnull ((1, 4));
+#endif
+
+
+/* Return the absolute value of X.  */
+extern int abs (int __x) __THROW __attribute__ ((__const__)) __wur;
+extern long int labs (long int __x) __THROW __attribute__ ((__const__)) __wur;
+
+#ifdef __USE_ISOC99
+__extension__ extern long long int llabs (long long int __x)
+     __THROW __attribute__ ((__const__)) __wur;
+#endif
+
+
+/* Return the `div_t', `ldiv_t' or `lldiv_t' representation
+   of the value of NUMER over DENOM. */
+/* GCC may have built-ins for these someday.  */
+extern div_t div (int __numer, int __denom)
+     __THROW __attribute__ ((__const__)) __wur;
+extern ldiv_t ldiv (long int __numer, long int __denom)
+     __THROW __attribute__ ((__const__)) __wur;
+
+#ifdef __USE_ISOC99
+__extension__ extern lldiv_t lldiv (long long int __numer,
+				    long long int __denom)
+     __THROW __attribute__ ((__const__)) __wur;
+#endif
+
+
+#if (defined __USE_XOPEN_EXTENDED && !defined __USE_XOPEN2K8) \
+    || defined __USE_MISC
+/* Convert floating point numbers to strings.  The returned values are
+   valid only until another call to the same function.  */
+
+/* Convert VALUE to a string with NDIGIT digits and return a pointer to
+   this.  Set *DECPT with the position of the decimal character and *SIGN
+   with the sign of the number.  */
+extern char *ecvt (double __value, int __ndigit, int *__restrict __decpt,
+		   int *__restrict __sign) __THROW __nonnull ((3, 4)) __wur;
+
+/* Convert VALUE to a string rounded to NDIGIT decimal digits.  Set *DECPT
+   with the position of the decimal character and *SIGN with the sign of
+   the number.  */
+extern char *fcvt (double __value, int __ndigit, int *__restrict __decpt,
+		   int *__restrict __sign) __THROW __nonnull ((3, 4)) __wur;
+
+/* If possible convert VALUE to a string with NDIGIT significant digits.
+   Otherwise use exponential representation.  The resulting string will
+   be written to BUF.  */
+extern char *gcvt (double __value, int __ndigit, char *__buf)
+     __THROW __nonnull ((3)) __wur;
+#endif
+
+#ifdef __USE_MISC
+/* Long double versions of above functions.  */
+extern char *qecvt (long double __value, int __ndigit,
+		    int *__restrict __decpt, int *__restrict __sign)
+     __THROW __nonnull ((3, 4)) __wur;
+extern char *qfcvt (long double __value, int __ndigit,
+		    int *__restrict __decpt, int *__restrict __sign)
+     __THROW __nonnull ((3, 4)) __wur;
+extern char *qgcvt (long double __value, int __ndigit, char *__buf)
+     __THROW __nonnull ((3)) __wur;
+
+
+/* Reentrant version of the functions above which provide their own
+   buffers.  */
+extern int ecvt_r (double __value, int __ndigit, int *__restrict __decpt,
+		   int *__restrict __sign, char *__restrict __buf,
+		   size_t __len) __THROW __nonnull ((3, 4, 5));
+extern int fcvt_r (double __value, int __ndigit, int *__restrict __decpt,
+		   int *__restrict __sign, char *__restrict __buf,
+		   size_t __len) __THROW __nonnull ((3, 4, 5));
+
+extern int qecvt_r (long double __value, int __ndigit,
+		    int *__restrict __decpt, int *__restrict __sign,
+		    char *__restrict __buf, size_t __len)
+     __THROW __nonnull ((3, 4, 5));
+extern int qfcvt_r (long double __value, int __ndigit,
+		    int *__restrict __decpt, int *__restrict __sign,
+		    char *__restrict __buf, size_t __len)
+     __THROW __nonnull ((3, 4, 5));
+#endif	/* misc */
+
+
+/* Return the length of the multibyte character
+   in S, which is no longer than N.  */
+extern int mblen (const char *__s, size_t __n) __THROW;
+/* Return the length of the given multibyte character,
+   putting its `wchar_t' representation in *PWC.  */
+extern int mbtowc (wchar_t *__restrict __pwc,
+		   const char *__restrict __s, size_t __n) __THROW;
+/* Put the multibyte character represented
+   by WCHAR in S, returning its length.  */
+extern int wctomb (char *__s, wchar_t __wchar) __THROW;
+
+
+/* Convert a multibyte string to a wide char string.  */
+extern size_t mbstowcs (wchar_t *__restrict  __pwcs,
+			const char *__restrict __s, size_t __n) __THROW
+    __attr_access ((__read_only__, 2));
+/* Convert a wide char string to multibyte string.  */
+extern size_t wcstombs (char *__restrict __s,
+			const wchar_t *__restrict __pwcs, size_t __n)
+     __THROW
+  __fortified_attr_access (__write_only__, 1, 3)
+  __attr_access ((__read_only__, 2));
+
+#ifdef __USE_MISC
+/* Determine whether the string value of RESPONSE matches the affirmation
+   or negative response expression as specified by the LC_MESSAGES category
+   in the program's current locale.  Returns 1 if affirmative, 0 if
+   negative, and -1 if not matching.  */
+extern int rpmatch (const char *__response) __THROW __nonnull ((1)) __wur;
+#endif
+
+
+#if defined __USE_XOPEN_EXTENDED || defined __USE_XOPEN2K8
+/* Parse comma separated suboption from *OPTIONP and match against
+   strings in TOKENS.  If found return index and set *VALUEP to
+   optional value introduced by an equal sign.  If the suboption is
+   not part of TOKENS return in *VALUEP beginning of unknown
+   suboption.  On exit *OPTIONP is set to the beginning of the next
+   token or at the terminating NUL character.  */
+extern int getsubopt (char **__restrict __optionp,
+		      char *const *__restrict __tokens,
+		      char **__restrict __valuep)
+     __THROW __nonnull ((1, 2, 3)) __wur;
+#endif
+
+
+/* X/Open pseudo terminal handling.  */
+
+#ifdef __USE_XOPEN2KXSI
+/* Return a master pseudo-terminal handle.  */
+extern int posix_openpt (int __oflag) __wur;
+#endif
+
+#ifdef __USE_XOPEN_EXTENDED
+/* The next four functions all take a master pseudo-tty fd and
+   perform an operation on the associated slave:  */
+
+/* Chown the slave to the calling user.  */
+extern int grantpt (int __fd) __THROW;
+
+/* Release an internal lock so the slave can be opened.
+   Call after grantpt().  */
+extern int unlockpt (int __fd) __THROW;
+
+/* Return the pathname of the pseudo terminal slave associated with
+   the master FD is open on, or NULL on errors.
+   The returned storage is good until the next call to this function.  */
+extern char *ptsname (int __fd) __THROW __wur;
+#endif
+
+#ifdef __USE_GNU
+/* Store at most BUFLEN characters of the pathname of the slave pseudo
+   terminal associated with the master FD is open on in BUF.
+   Return 0 on success, otherwise an error number.  */
+extern int ptsname_r (int __fd, char *__buf, size_t __buflen)
+     __THROW __nonnull ((2)) __fortified_attr_access (__write_only__, 2, 3);
+
+/* Open a master pseudo terminal and return its file descriptor.  */
+extern int getpt (void);
+#endif
+
+#ifdef __USE_MISC
+/* Put the 1 minute, 5 minute and 15 minute load averages into the first
+   NELEM elements of LOADAVG.  Return the number written (never more than
+   three, but may be less than NELEM), or -1 if an error occurred.  */
+extern int getloadavg (double __loadavg[], int __nelem)
+     __THROW __nonnull ((1));
+#endif
+
+#if defined __USE_XOPEN_EXTENDED && !defined __USE_XOPEN2K
+/* Return the index into the active-logins file (utmp) for
+   the controlling terminal.  */
+extern int ttyslot (void) __THROW;
+#endif
+
+#include <bits/stdlib-float.h>
+
+/* Define some macros helping to catch buffer overflows.  */
+#if __USE_FORTIFY_LEVEL > 0 && defined __fortify_function
+# include <bits/stdlib.h>
+#endif
+
+#include <bits/floatn.h>
+#if defined __LDBL_COMPAT || __LDOUBLE_REDIRECTS_TO_FLOAT128_ABI == 1
+# include <bits/stdlib-ldbl.h>
+#endif
+
+__END_DECLS
+
+#endif /* stdlib.h  */
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@string.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@string.h
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@string.h
@@ -0,0 +1,541 @@
+/* Copyright (C) 1991-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+/*
+ *	ISO C99 Standard: 7.21 String handling	<string.h>
+ */
+
+#ifndef	_STRING_H
+#define	_STRING_H	1
+
+#define __GLIBC_INTERNAL_STARTING_HEADER_IMPLEMENTATION
+#include <bits/libc-header-start.h>
+
+__BEGIN_DECLS
+
+/* Get size_t and NULL from <stddef.h>.  */
+#define	__need_size_t
+#define	__need_NULL
+#include <stddef.h>
+
+/* Tell the caller that we provide correct C++ prototypes.  */
+#if defined __cplusplus && (__GNUC_PREREQ (4, 4) \
+			    || __glibc_clang_prereq (3, 5))
+# define __CORRECT_ISO_CPP_STRING_H_PROTO
+#endif
+
+
+/* Copy N bytes of SRC to DEST.  */
+extern void *memcpy (void *__restrict __dest, const void *__restrict __src,
+		     size_t __n) __THROW __nonnull ((1, 2));
+/* Copy N bytes of SRC to DEST, guaranteeing
+   correct behavior for overlapping strings.  */
+extern void *memmove (void *__dest, const void *__src, size_t __n)
+     __THROW __nonnull ((1, 2));
+
+/* Copy no more than N bytes of SRC to DEST, stopping when C is found.
+   Return the position in DEST one byte past where C was copied,
+   or NULL if C was not found in the first N bytes of SRC.  */
+#if defined __USE_MISC || defined __USE_XOPEN || __GLIBC_USE (ISOC2X)
+extern void *memccpy (void *__restrict __dest, const void *__restrict __src,
+		      int __c, size_t __n)
+    __THROW __nonnull ((1, 2)) __attr_access ((__write_only__, 1, 4));
+#endif /* Misc || X/Open.  */
+
+
+/* Set N bytes of S to C.  */
+extern void *memset (void *__s, int __c, size_t __n) __THROW __nonnull ((1));
+
+/* Compare N bytes of S1 and S2.  */
+extern int memcmp (const void *__s1, const void *__s2, size_t __n)
+     __THROW __attribute_pure__ __nonnull ((1, 2));
+
+/* Compare N bytes of S1 and S2.  Return zero if S1 and S2 are equal.
+   Return some non-zero value otherwise.
+
+   Essentially __memcmpeq has the exact same semantics as memcmp
+   except the return value is less constrained.  memcmp is always a
+   correct implementation of __memcmpeq.  As well !!memcmp, -memcmp,
+   or bcmp are correct implementations.
+
+   __memcmpeq is meant to be used by compilers when memcmp return is
+   only used for its bolean value.
+
+   __memcmpeq is declared only for use by compilers.  Programs should
+   continue to use memcmp.  */
+extern int __memcmpeq (const void *__s1, const void *__s2, size_t __n)
+     __THROW __attribute_pure__ __nonnull ((1, 2));
+
+/* Search N bytes of S for C.  */
+#ifdef __CORRECT_ISO_CPP_STRING_H_PROTO
+extern "C++"
+{
+extern void *memchr (void *__s, int __c, size_t __n)
+      __THROW __asm ("memchr") __attribute_pure__ __nonnull ((1));
+extern const void *memchr (const void *__s, int __c, size_t __n)
+      __THROW __asm ("memchr") __attribute_pure__ __nonnull ((1));
+
+# ifdef __OPTIMIZE__
+__extern_always_inline void *
+memchr (void *__s, int __c, size_t __n) __THROW
+{
+  return __builtin_memchr (__s, __c, __n);
+}
+
+__extern_always_inline const void *
+memchr (const void *__s, int __c, size_t __n) __THROW
+{
+  return __builtin_memchr (__s, __c, __n);
+}
+# endif
+}
+#else
+extern void *memchr (const void *__s, int __c, size_t __n)
+      __THROW __attribute_pure__ __nonnull ((1));
+#endif
+
+#ifdef __USE_GNU
+/* Search in S for C.  This is similar to `memchr' but there is no
+   length limit.  */
+# ifdef __CORRECT_ISO_CPP_STRING_H_PROTO
+extern "C++" void *rawmemchr (void *__s, int __c)
+     __THROW __asm ("rawmemchr") __attribute_pure__ __nonnull ((1));
+extern "C++" const void *rawmemchr (const void *__s, int __c)
+     __THROW __asm ("rawmemchr") __attribute_pure__ __nonnull ((1));
+# else
+extern void *rawmemchr (const void *__s, int __c)
+     __THROW __attribute_pure__ __nonnull ((1));
+# endif
+
+/* Search N bytes of S for the final occurrence of C.  */
+# ifdef __CORRECT_ISO_CPP_STRING_H_PROTO
+extern "C++" void *memrchr (void *__s, int __c, size_t __n)
+      __THROW __asm ("memrchr") __attribute_pure__ __nonnull ((1))
+      __attr_access ((__read_only__, 1, 3));
+extern "C++" const void *memrchr (const void *__s, int __c, size_t __n)
+      __THROW __asm ("memrchr") __attribute_pure__ __nonnull ((1))
+      __attr_access ((__read_only__, 1, 3));
+# else
+extern void *memrchr (const void *__s, int __c, size_t __n)
+      __THROW __attribute_pure__ __nonnull ((1))
+      __attr_access ((__read_only__, 1, 3));
+# endif
+#endif
+
+
+/* Copy SRC to DEST.  */
+extern char *strcpy (char *__restrict __dest, const char *__restrict __src)
+     __THROW __nonnull ((1, 2));
+/* Copy no more than N characters of SRC to DEST.  */
+extern char *strncpy (char *__restrict __dest,
+		      const char *__restrict __src, size_t __n)
+     __THROW __nonnull ((1, 2));
+
+/* Append SRC onto DEST.  */
+extern char *strcat (char *__restrict __dest, const char *__restrict __src)
+     __THROW __nonnull ((1, 2));
+/* Append no more than N characters from SRC onto DEST.  */
+extern char *strncat (char *__restrict __dest, const char *__restrict __src,
+		      size_t __n) __THROW __nonnull ((1, 2));
+
+/* Compare S1 and S2.  */
+extern int strcmp (const char *__s1, const char *__s2)
+     __THROW __attribute_pure__ __nonnull ((1, 2));
+/* Compare N characters of S1 and S2.  */
+extern int strncmp (const char *__s1, const char *__s2, size_t __n)
+     __THROW __attribute_pure__ __nonnull ((1, 2));
+
+/* Compare the collated forms of S1 and S2.  */
+extern int strcoll (const char *__s1, const char *__s2)
+     __THROW __attribute_pure__ __nonnull ((1, 2));
+/* Put a transformation of SRC into no more than N bytes of DEST.  */
+extern size_t strxfrm (char *__restrict __dest,
+		       const char *__restrict __src, size_t __n)
+    __THROW __nonnull ((2)) __attr_access ((__write_only__, 1, 3));
+
+#ifdef __USE_XOPEN2K8
+/* POSIX.1-2008 extended locale interface (see locale.h).  */
+# include <bits/types/locale_t.h>
+
+/* Compare the collated forms of S1 and S2, using sorting rules from L.  */
+extern int strcoll_l (const char *__s1, const char *__s2, locale_t __l)
+     __THROW __attribute_pure__ __nonnull ((1, 2, 3));
+/* Put a transformation of SRC into no more than N bytes of DEST,
+   using sorting rules from L.  */
+extern size_t strxfrm_l (char *__dest, const char *__src, size_t __n,
+			 locale_t __l) __THROW __nonnull ((2, 4))
+     __attr_access ((__write_only__, 1, 3));
+#endif
+
+#if (defined __USE_XOPEN_EXTENDED || defined __USE_XOPEN2K8	\
+     || __GLIBC_USE (LIB_EXT2) || __GLIBC_USE (ISOC2X))
+/* Duplicate S, returning an identical malloc'd string.  */
+extern char *strdup (const char *__s)
+     __THROW __attribute_malloc__ __nonnull ((1));
+#endif
+
+/* Return a malloc'd copy of at most N bytes of STRING.  The
+   resultant string is terminated even if no null terminator
+   appears before STRING[N].  */
+#if defined __USE_XOPEN2K8 || __GLIBC_USE (LIB_EXT2) || __GLIBC_USE (ISOC2X)
+extern char *strndup (const char *__string, size_t __n)
+     __THROW __attribute_malloc__ __nonnull ((1));
+#endif
+
+#if defined __USE_GNU && defined __GNUC__
+/* Duplicate S, returning an identical alloca'd string.  */
+# define strdupa(s)							      \
+  (__extension__							      \
+    ({									      \
+      const char *__old = (s);						      \
+      size_t __len = strlen (__old) + 1;				      \
+      char *__new = (char *) __builtin_alloca (__len);			      \
+      (char *) memcpy (__new, __old, __len);				      \
+    }))
+
+/* Return an alloca'd copy of at most N bytes of string.  */
+# define strndupa(s, n)							      \
+  (__extension__							      \
+    ({									      \
+      const char *__old = (s);						      \
+      size_t __len = strnlen (__old, (n));				      \
+      char *__new = (char *) __builtin_alloca (__len + 1);		      \
+      __new[__len] = '\0';						      \
+      (char *) memcpy (__new, __old, __len);				      \
+    }))
+#endif
+
+/* Find the first occurrence of C in S.  */
+#ifdef __CORRECT_ISO_CPP_STRING_H_PROTO
+extern "C++"
+{
+extern char *strchr (char *__s, int __c)
+     __THROW __asm ("strchr") __attribute_pure__ __nonnull ((1));
+extern const char *strchr (const char *__s, int __c)
+     __THROW __asm ("strchr") __attribute_pure__ __nonnull ((1));
+
+# ifdef __OPTIMIZE__
+__extern_always_inline char *
+strchr (char *__s, int __c) __THROW
+{
+  return __builtin_strchr (__s, __c);
+}
+
+__extern_always_inline const char *
+strchr (const char *__s, int __c) __THROW
+{
+  return __builtin_strchr (__s, __c);
+}
+# endif
+}
+#else
+extern char *strchr (const char *__s, int __c)
+     __THROW __attribute_pure__ __nonnull ((1));
+#endif
+/* Find the last occurrence of C in S.  */
+#ifdef __CORRECT_ISO_CPP_STRING_H_PROTO
+extern "C++"
+{
+extern char *strrchr (char *__s, int __c)
+     __THROW __asm ("strrchr") __attribute_pure__ __nonnull ((1));
+extern const char *strrchr (const char *__s, int __c)
+     __THROW __asm ("strrchr") __attribute_pure__ __nonnull ((1));
+
+# ifdef __OPTIMIZE__
+__extern_always_inline char *
+strrchr (char *__s, int __c) __THROW
+{
+  return __builtin_strrchr (__s, __c);
+}
+
+__extern_always_inline const char *
+strrchr (const char *__s, int __c) __THROW
+{
+  return __builtin_strrchr (__s, __c);
+}
+# endif
+}
+#else
+extern char *strrchr (const char *__s, int __c)
+     __THROW __attribute_pure__ __nonnull ((1));
+#endif
+
+#ifdef __USE_GNU
+/* This function is similar to `strchr'.  But it returns a pointer to
+   the closing NUL byte in case C is not found in S.  */
+# ifdef __CORRECT_ISO_CPP_STRING_H_PROTO
+extern "C++" char *strchrnul (char *__s, int __c)
+     __THROW __asm ("strchrnul") __attribute_pure__ __nonnull ((1));
+extern "C++" const char *strchrnul (const char *__s, int __c)
+     __THROW __asm ("strchrnul") __attribute_pure__ __nonnull ((1));
+# else
+extern char *strchrnul (const char *__s, int __c)
+     __THROW __attribute_pure__ __nonnull ((1));
+# endif
+#endif
+
+/* Return the length of the initial segment of S which
+   consists entirely of characters not in REJECT.  */
+extern size_t strcspn (const char *__s, const char *__reject)
+     __THROW __attribute_pure__ __nonnull ((1, 2));
+/* Return the length of the initial segment of S which
+   consists entirely of characters in ACCEPT.  */
+extern size_t strspn (const char *__s, const char *__accept)
+     __THROW __attribute_pure__ __nonnull ((1, 2));
+/* Find the first occurrence in S of any character in ACCEPT.  */
+#ifdef __CORRECT_ISO_CPP_STRING_H_PROTO
+extern "C++"
+{
+extern char *strpbrk (char *__s, const char *__accept)
+     __THROW __asm ("strpbrk") __attribute_pure__ __nonnull ((1, 2));
+extern const char *strpbrk (const char *__s, const char *__accept)
+     __THROW __asm ("strpbrk") __attribute_pure__ __nonnull ((1, 2));
+
+# ifdef __OPTIMIZE__
+__extern_always_inline char *
+strpbrk (char *__s, const char *__accept) __THROW
+{
+  return __builtin_strpbrk (__s, __accept);
+}
+
+__extern_always_inline const char *
+strpbrk (const char *__s, const char *__accept) __THROW
+{
+  return __builtin_strpbrk (__s, __accept);
+}
+# endif
+}
+#else
+extern char *strpbrk (const char *__s, const char *__accept)
+     __THROW __attribute_pure__ __nonnull ((1, 2));
+#endif
+/* Find the first occurrence of NEEDLE in HAYSTACK.  */
+#ifdef __CORRECT_ISO_CPP_STRING_H_PROTO
+extern "C++"
+{
+extern char *strstr (char *__haystack, const char *__needle)
+     __THROW __asm ("strstr") __attribute_pure__ __nonnull ((1, 2));
+extern const char *strstr (const char *__haystack, const char *__needle)
+     __THROW __asm ("strstr") __attribute_pure__ __nonnull ((1, 2));
+
+# ifdef __OPTIMIZE__
+__extern_always_inline char *
+strstr (char *__haystack, const char *__needle) __THROW
+{
+  return __builtin_strstr (__haystack, __needle);
+}
+
+__extern_always_inline const char *
+strstr (const char *__haystack, const char *__needle) __THROW
+{
+  return __builtin_strstr (__haystack, __needle);
+}
+# endif
+}
+#else
+extern char *strstr (const char *__haystack, const char *__needle)
+     __THROW __attribute_pure__ __nonnull ((1, 2));
+#endif
+
+
+/* Divide S into tokens separated by characters in DELIM.  */
+extern char *strtok (char *__restrict __s, const char *__restrict __delim)
+     __THROW __nonnull ((2));
+
+/* Divide S into tokens separated by characters in DELIM.  Information
+   passed between calls are stored in SAVE_PTR.  */
+extern char *__strtok_r (char *__restrict __s,
+			 const char *__restrict __delim,
+			 char **__restrict __save_ptr)
+     __THROW __nonnull ((2, 3));
+#ifdef __USE_POSIX
+extern char *strtok_r (char *__restrict __s, const char *__restrict __delim,
+		       char **__restrict __save_ptr)
+     __THROW __nonnull ((2, 3));
+#endif
+
+#ifdef __USE_GNU
+/* Similar to `strstr' but this function ignores the case of both strings.  */
+# ifdef __CORRECT_ISO_CPP_STRING_H_PROTO
+extern "C++" char *strcasestr (char *__haystack, const char *__needle)
+     __THROW __asm ("strcasestr") __attribute_pure__ __nonnull ((1, 2));
+extern "C++" const char *strcasestr (const char *__haystack,
+				     const char *__needle)
+     __THROW __asm ("strcasestr") __attribute_pure__ __nonnull ((1, 2));
+# else
+extern char *strcasestr (const char *__haystack, const char *__needle)
+     __THROW __attribute_pure__ __nonnull ((1, 2));
+# endif
+#endif
+
+#ifdef __USE_GNU
+/* Find the first occurrence of NEEDLE in HAYSTACK.
+   NEEDLE is NEEDLELEN bytes long;
+   HAYSTACK is HAYSTACKLEN bytes long.  */
+extern void *memmem (const void *__haystack, size_t __haystacklen,
+		     const void *__needle, size_t __needlelen)
+     __THROW __attribute_pure__ __nonnull ((1, 3))
+    __attr_access ((__read_only__, 1, 2))
+    __attr_access ((__read_only__, 3, 4));
+
+/* Copy N bytes of SRC to DEST, return pointer to bytes after the
+   last written byte.  */
+extern void *__mempcpy (void *__restrict __dest,
+			const void *__restrict __src, size_t __n)
+     __THROW __nonnull ((1, 2));
+extern void *mempcpy (void *__restrict __dest,
+		      const void *__restrict __src, size_t __n)
+     __THROW __nonnull ((1, 2));
+#endif
+
+
+/* Return the length of S.  */
+extern size_t strlen (const char *__s)
+     __THROW __attribute_pure__ __nonnull ((1));
+
+#ifdef	__USE_XOPEN2K8
+/* Find the length of STRING, but scan at most MAXLEN characters.
+   If no '\0' terminator is found in that many characters, return MAXLEN.  */
+extern size_t strnlen (const char *__string, size_t __maxlen)
+     __THROW __attribute_pure__ __nonnull ((1));
+#endif
+
+
+/* Return a string describing the meaning of the `errno' code in ERRNUM.  */
+extern char *strerror (int __errnum) __THROW;
+#ifdef __USE_XOPEN2K
+/* Reentrant version of `strerror'.
+   There are 2 flavors of `strerror_r', GNU which returns the string
+   and may or may not use the supplied temporary buffer and POSIX one
+   which fills the string into the buffer.
+   To use the POSIX version, -D_XOPEN_SOURCE=600 or -D_POSIX_C_SOURCE=200112L
+   without -D_GNU_SOURCE is needed, otherwise the GNU version is
+   preferred.  */
+# if defined __USE_XOPEN2K && !defined __USE_GNU
+/* Fill BUF with a string describing the meaning of the `errno' code in
+   ERRNUM.  */
+#  ifdef __REDIRECT_NTH
+extern int __REDIRECT_NTH (strerror_r,
+			   (int __errnum, char *__buf, size_t __buflen),
+			   __xpg_strerror_r) __nonnull ((2))
+    __attr_access ((__write_only__, 2, 3));
+#  else
+extern int __xpg_strerror_r (int __errnum, char *__buf, size_t __buflen)
+     __THROW __nonnull ((2)) __attr_access ((__write_only__, 2, 3));
+#   define strerror_r __xpg_strerror_r
+#  endif
+# else
+/* If a temporary buffer is required, at most BUFLEN bytes of BUF will be
+   used.  */
+extern char *strerror_r (int __errnum, char *__buf, size_t __buflen)
+     __THROW __nonnull ((2)) __wur  __attr_access ((__write_only__, 2, 3));
+# endif
+
+# ifdef __USE_GNU
+/* Return a string describing the meaning of tthe error in ERR.  */
+extern const char *strerrordesc_np (int __err) __THROW;
+/* Return a string with the error name in ERR.  */
+extern const char *strerrorname_np (int __err) __THROW;
+# endif
+#endif
+
+#ifdef __USE_XOPEN2K8
+/* Translate error number to string according to the locale L.  */
+extern char *strerror_l (int __errnum, locale_t __l) __THROW;
+#endif
+
+#ifdef __USE_MISC
+# include <strings.h>
+
+/* Set N bytes of S to 0.  The compiler will not delete a call to this
+   function, even if S is dead after the call.  */
+extern void explicit_bzero (void *__s, size_t __n) __THROW __nonnull ((1))
+    __fortified_attr_access (__write_only__, 1, 2);
+
+/* Return the next DELIM-delimited token from *STRINGP,
+   terminating it with a '\0', and update *STRINGP to point past it.  */
+extern char *strsep (char **__restrict __stringp,
+		     const char *__restrict __delim)
+     __THROW __nonnull ((1, 2));
+#endif
+
+#ifdef	__USE_XOPEN2K8
+/* Return a string describing the meaning of the signal number in SIG.  */
+extern char *strsignal (int __sig) __THROW;
+
+# ifdef __USE_GNU
+/* Return an abbreviation string for the signal number SIG.  */
+extern const char *sigabbrev_np (int __sig) __THROW;
+/* Return a string describing the meaning of the signal number in SIG,
+   the result is not translated.  */
+extern const char *sigdescr_np (int __sig) __THROW;
+# endif
+
+/* Copy SRC to DEST, returning the address of the terminating '\0' in DEST.  */
+extern char *__stpcpy (char *__restrict __dest, const char *__restrict __src)
+     __THROW __nonnull ((1, 2));
+extern char *stpcpy (char *__restrict __dest, const char *__restrict __src)
+     __THROW __nonnull ((1, 2));
+
+/* Copy no more than N characters of SRC to DEST, returning the address of
+   the last character written into DEST.  */
+extern char *__stpncpy (char *__restrict __dest,
+			const char *__restrict __src, size_t __n)
+     __THROW __nonnull ((1, 2));
+extern char *stpncpy (char *__restrict __dest,
+		      const char *__restrict __src, size_t __n)
+     __THROW __nonnull ((1, 2));
+#endif
+
+#ifdef	__USE_GNU
+/* Compare S1 and S2 as strings holding name & indices/version numbers.  */
+extern int strverscmp (const char *__s1, const char *__s2)
+     __THROW __attribute_pure__ __nonnull ((1, 2));
+
+/* Sautee STRING briskly.  */
+extern char *strfry (char *__string) __THROW __nonnull ((1));
+
+/* Frobnicate N bytes of S.  */
+extern void *memfrob (void *__s, size_t __n) __THROW __nonnull ((1))
+    __attr_access ((__read_write__, 1, 2));
+
+# ifndef basename
+/* Return the file name within directory of FILENAME.  We don't
+   declare the function if the `basename' macro is available (defined
+   in <libgen.h>) which makes the XPG version of this function
+   available.  */
+#  ifdef __CORRECT_ISO_CPP_STRING_H_PROTO
+extern "C++" char *basename (char *__filename)
+     __THROW __asm ("basename") __nonnull ((1));
+extern "C++" const char *basename (const char *__filename)
+     __THROW __asm ("basename") __nonnull ((1));
+#  else
+extern char *basename (const char *__filename) __THROW __nonnull ((1));
+#  endif
+# endif
+#endif
+
+#if __GNUC_PREREQ (3,4)
+# if __USE_FORTIFY_LEVEL > 0 && defined __fortify_function
+/* Functions with security checks.  */
+#  include <bits/string_fortified.h>
+# endif
+#endif
+
+__END_DECLS
+
+#endif /* string.h  */
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@strings.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@strings.h
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@strings.h
@@ -0,0 +1,148 @@
+/* Copyright (C) 1991-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef	_STRINGS_H
+#define	_STRINGS_H	1
+
+#include <features.h>
+#define __need_size_t
+#include <stddef.h>
+
+/* Tell the caller that we provide correct C++ prototypes.  */
+#if defined __cplusplus && __GNUC_PREREQ (4, 4)
+# define __CORRECT_ISO_CPP_STRINGS_H_PROTO
+#endif
+
+__BEGIN_DECLS
+
+#if defined __USE_MISC || !defined __USE_XOPEN2K8
+/* Compare N bytes of S1 and S2 (same as memcmp).  */
+extern int bcmp (const void *__s1, const void *__s2, size_t __n)
+     __THROW __attribute_pure__ __nonnull ((1, 2));
+
+/* Copy N bytes of SRC to DEST (like memmove, but args reversed).  */
+extern void bcopy (const void *__src, void *__dest, size_t __n)
+  __THROW __nonnull ((1, 2));
+
+/* Set N bytes of S to 0.  */
+extern void bzero (void *__s, size_t __n) __THROW __nonnull ((1));
+
+/* Find the first occurrence of C in S (same as strchr).  */
+# ifdef __CORRECT_ISO_CPP_STRINGS_H_PROTO
+extern "C++"
+{
+extern char *index (char *__s, int __c)
+     __THROW __asm ("index") __attribute_pure__ __nonnull ((1));
+extern const char *index (const char *__s, int __c)
+     __THROW __asm ("index") __attribute_pure__ __nonnull ((1));
+
+#  if defined __OPTIMIZE__
+__extern_always_inline char *
+index (char *__s, int __c) __THROW
+{
+  return __builtin_index (__s, __c);
+}
+
+__extern_always_inline const char *
+index (const char *__s, int __c) __THROW
+{
+  return __builtin_index (__s, __c);
+}
+#  endif
+}
+# else
+extern char *index (const char *__s, int __c)
+     __THROW __attribute_pure__ __nonnull ((1));
+# endif
+
+/* Find the last occurrence of C in S (same as strrchr).  */
+# ifdef __CORRECT_ISO_CPP_STRINGS_H_PROTO
+extern "C++"
+{
+extern char *rindex (char *__s, int __c)
+     __THROW __asm ("rindex") __attribute_pure__ __nonnull ((1));
+extern const char *rindex (const char *__s, int __c)
+     __THROW __asm ("rindex") __attribute_pure__ __nonnull ((1));
+
+#  if defined __OPTIMIZE__
+__extern_always_inline char *
+rindex (char *__s, int __c) __THROW
+{
+  return __builtin_rindex (__s, __c);
+}
+
+__extern_always_inline const char *
+rindex (const char *__s, int __c) __THROW
+{
+  return __builtin_rindex (__s, __c);
+}
+#  endif
+}
+# else
+extern char *rindex (const char *__s, int __c)
+     __THROW __attribute_pure__ __nonnull ((1));
+# endif
+#endif
+
+#if defined __USE_MISC || !defined __USE_XOPEN2K8 || defined __USE_XOPEN2K8XSI
+/* Return the position of the first bit set in I, or 0 if none are set.
+   The least-significant bit is position 1, the most-significant 32.  */
+extern int ffs (int __i) __THROW __attribute_const__;
+#endif
+
+/* The following two functions are non-standard but necessary for non-32 bit
+   platforms.  */
+# ifdef	__USE_MISC
+extern int ffsl (long int __l) __THROW __attribute_const__;
+__extension__ extern int ffsll (long long int __ll)
+     __THROW __attribute_const__;
+# endif
+
+/* Compare S1 and S2, ignoring case.  */
+extern int strcasecmp (const char *__s1, const char *__s2)
+     __THROW __attribute_pure__ __nonnull ((1, 2));
+
+/* Compare no more than N chars of S1 and S2, ignoring case.  */
+extern int strncasecmp (const char *__s1, const char *__s2, size_t __n)
+     __THROW __attribute_pure__ __nonnull ((1, 2));
+
+#ifdef	__USE_XOPEN2K8
+/* POSIX.1-2008 extended locale interface (see locale.h).  */
+# include <bits/types/locale_t.h>
+
+/* Compare S1 and S2, ignoring case, using collation rules from LOC.  */
+extern int strcasecmp_l (const char *__s1, const char *__s2, locale_t __loc)
+     __THROW __attribute_pure__ __nonnull ((1, 2, 3));
+
+/* Compare no more than N chars of S1 and S2, ignoring case, using
+   collation rules from LOC.  */
+extern int strncasecmp_l (const char *__s1, const char *__s2,
+			  size_t __n, locale_t __loc)
+     __THROW __attribute_pure__ __nonnull ((1, 2, 4));
+#endif
+
+__END_DECLS
+
+#if __GNUC_PREREQ (3,4) && __USE_FORTIFY_LEVEL > 0 \
+    && defined __fortify_function
+/* Functions with security checks.  */
+# if defined __USE_MISC || !defined __USE_XOPEN2K8
+#  include <bits/strings_fortified.h>
+# endif
+#endif
+
+#endif	/* strings.h  */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@strings.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@strings.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@sys@cdefs.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@sys@cdefs.h
new file mode 100644
index 0000000000000000000000000000000000000000..1c2b044a0d27da18709a95f1ccecdf556434b173
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@sys@cdefs.h
@@ -0,0 +1,705 @@
+/* Copyright (C) 1992-2022 Free Software Foundation, Inc.
+   Copyright The GNU Toolchain Authors.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef	_SYS_CDEFS_H
+#define	_SYS_CDEFS_H	1
+
+/* We are almost always included from features.h. */
+#ifndef _FEATURES_H
+# include <features.h>
+#endif
+
+/* The GNU libc does not support any K&R compilers or the traditional mode
+   of ISO C compilers anymore.  Check for some of the combinations not
+   supported anymore.  */
+#if defined __GNUC__ && !defined __STDC__
+# error "You need a ISO C conforming compiler to use the glibc headers"
+#endif
+
+/* Some user header file might have defined this before.  */
+#undef	__P
+#undef	__PMT
+
+/* Compilers that lack __has_attribute may object to
+       #if defined __has_attribute && __has_attribute (...)
+   even though they do not need to evaluate the right-hand side of the &&.
+   Similarly for __has_builtin, etc.  */
+#if (defined __has_attribute \
+     && (!defined __clang_minor__ \
+         || 3 < __clang_major__ + (5 <= __clang_minor__)))
+# define __glibc_has_attribute(attr) __has_attribute (attr)
+#else
+# define __glibc_has_attribute(attr) 0
+#endif
+#ifdef __has_builtin
+# define __glibc_has_builtin(name) __has_builtin (name)
+#else
+# define __glibc_has_builtin(name) 0
+#endif
+#ifdef __has_extension
+# define __glibc_has_extension(ext) __has_extension (ext)
+#else
+# define __glibc_has_extension(ext) 0
+#endif
+
+#if defined __GNUC__ || defined __clang__
+
+/* All functions, except those with callbacks or those that
+   synchronize memory, are leaf functions.  */
+# if __GNUC_PREREQ (4, 6) && !defined _LIBC
+#  define __LEAF , __leaf__
+#  define __LEAF_ATTR __attribute__ ((__leaf__))
+# else
+#  define __LEAF
+#  define __LEAF_ATTR
+# endif
+
+/* GCC can always grok prototypes.  For C++ programs we add throw()
+   to help it optimize the function calls.  But this only works with
+   gcc 2.8.x and egcs.  For gcc 3.4 and up we even mark C functions
+   as non-throwing using a function attribute since programs can use
+   the -fexceptions options for C code as well.  */
+# if !defined __cplusplus \
+     && (__GNUC_PREREQ (3, 4) || __glibc_has_attribute (__nothrow__))
+#  define __THROW	__attribute__ ((__nothrow__ __LEAF))
+#  define __THROWNL	__attribute__ ((__nothrow__))
+#  define __NTH(fct)	__attribute__ ((__nothrow__ __LEAF)) fct
+#  define __NTHNL(fct)  __attribute__ ((__nothrow__)) fct
+# else
+#  if defined __cplusplus && (__GNUC_PREREQ (2,8) || __clang_major >= 4)
+#   if __cplusplus >= 201103L
+#    define __THROW	noexcept (true)
+#   else
+#    define __THROW	throw ()
+#   endif
+#   define __THROWNL	__THROW
+#   define __NTH(fct)	__LEAF_ATTR fct __THROW
+#   define __NTHNL(fct) fct __THROW
+#  else
+#   define __THROW
+#   define __THROWNL
+#   define __NTH(fct)	fct
+#   define __NTHNL(fct) fct
+#  endif
+# endif
+
+#else	/* Not GCC or clang.  */
+
+# if (defined __cplusplus						\
+      || (defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L))
+#  define __inline	inline
+# else
+#  define __inline		/* No inline functions.  */
+# endif
+
+# define __THROW
+# define __THROWNL
+# define __NTH(fct)	fct
+
+#endif	/* GCC || clang.  */
+
+/* These two macros are not used in glibc anymore.  They are kept here
+   only because some other projects expect the macros to be defined.  */
+#define __P(args)	args
+#define __PMT(args)	args
+
+/* For these things, GCC behaves the ANSI way normally,
+   and the non-ANSI way under -traditional.  */
+
+#define __CONCAT(x,y)	x ## y
+#define __STRING(x)	#x
+
+/* This is not a typedef so `const __ptr_t' does the right thing.  */
+#define __ptr_t void *
+
+
+/* C++ needs to know that types and declarations are C, not C++.  */
+#ifdef	__cplusplus
+# define __BEGIN_DECLS	extern "C" {
+# define __END_DECLS	}
+#else
+# define __BEGIN_DECLS
+# define __END_DECLS
+#endif
+
+
+/* Fortify support.  */
+#define __bos(ptr) __builtin_object_size (ptr, __USE_FORTIFY_LEVEL > 1)
+#define __bos0(ptr) __builtin_object_size (ptr, 0)
+
+/* Use __builtin_dynamic_object_size at _FORTIFY_SOURCE=3 when available.  */
+#if __USE_FORTIFY_LEVEL == 3 && (__glibc_clang_prereq (9, 0)		      \
+				 || __GNUC_PREREQ (12, 0))
+# define __glibc_objsize0(__o) __builtin_dynamic_object_size (__o, 0)
+# define __glibc_objsize(__o) __builtin_dynamic_object_size (__o, 1)
+#else
+# define __glibc_objsize0(__o) __bos0 (__o)
+# define __glibc_objsize(__o) __bos (__o)
+#endif
+
+/* Compile time conditions to choose between the regular, _chk and _chk_warn
+   variants.  These conditions should get evaluated to constant and optimized
+   away.  */
+
+#define __glibc_safe_len_cond(__l, __s, __osz) ((__l) <= (__osz) / (__s))
+#define __glibc_unsigned_or_positive(__l) \
+  ((__typeof (__l)) 0 < (__typeof (__l)) -1				      \
+   || (__builtin_constant_p (__l) && (__l) > 0))
+
+/* Length is known to be safe at compile time if the __L * __S <= __OBJSZ
+   condition can be folded to a constant and if it is true, or unknown (-1) */
+#define __glibc_safe_or_unknown_len(__l, __s, __osz) \
+  ((__builtin_constant_p (__osz) && (__osz) == (__SIZE_TYPE__) -1)	      \
+   || (__glibc_unsigned_or_positive (__l)				      \
+       && __builtin_constant_p (__glibc_safe_len_cond ((__SIZE_TYPE__) (__l), \
+						       (__s), (__osz)))	      \
+       && __glibc_safe_len_cond ((__SIZE_TYPE__) (__l), (__s), (__osz))))
+
+/* Conversely, we know at compile time that the length is unsafe if the
+   __L * __S <= __OBJSZ condition can be folded to a constant and if it is
+   false.  */
+#define __glibc_unsafe_len(__l, __s, __osz) \
+  (__glibc_unsigned_or_positive (__l)					      \
+   && __builtin_constant_p (__glibc_safe_len_cond ((__SIZE_TYPE__) (__l),     \
+						   __s, __osz))		      \
+   && !__glibc_safe_len_cond ((__SIZE_TYPE__) (__l), __s, __osz))
+
+/* Fortify function f.  __f_alias, __f_chk and __f_chk_warn must be
+   declared.  */
+
+#define __glibc_fortify(f, __l, __s, __osz, ...) \
+  (__glibc_safe_or_unknown_len (__l, __s, __osz)			      \
+   ? __ ## f ## _alias (__VA_ARGS__)					      \
+   : (__glibc_unsafe_len (__l, __s, __osz)				      \
+      ? __ ## f ## _chk_warn (__VA_ARGS__, __osz)			      \
+      : __ ## f ## _chk (__VA_ARGS__, __osz)))			      \
+
+/* Fortify function f, where object size argument passed to f is the number of
+   elements and not total size.  */
+
+#define __glibc_fortify_n(f, __l, __s, __osz, ...) \
+  (__glibc_safe_or_unknown_len (__l, __s, __osz)			      \
+   ? __ ## f ## _alias (__VA_ARGS__)					      \
+   : (__glibc_unsafe_len (__l, __s, __osz)				      \
+      ? __ ## f ## _chk_warn (__VA_ARGS__, (__osz) / (__s))		      \
+      : __ ## f ## _chk (__VA_ARGS__, (__osz) / (__s))))		      \
+
+#if __GNUC_PREREQ (4,3)
+# define __warnattr(msg) __attribute__((__warning__ (msg)))
+# define __errordecl(name, msg) \
+  extern void name (void) __attribute__((__error__ (msg)))
+#else
+# define __warnattr(msg)
+# define __errordecl(name, msg) extern void name (void)
+#endif
+
+/* Support for flexible arrays.
+   Headers that should use flexible arrays only if they're "real"
+   (e.g. only if they won't affect sizeof()) should test
+   #if __glibc_c99_flexarr_available.  */
+#if defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L && !defined __HP_cc
+# define __flexarr	[]
+# define __glibc_c99_flexarr_available 1
+#elif __GNUC_PREREQ (2,97) || defined __clang__
+/* GCC 2.97 and clang support C99 flexible array members as an extension,
+   even when in C89 mode or compiling C++ (any version).  */
+# define __flexarr	[]
+# define __glibc_c99_flexarr_available 1
+#elif defined __GNUC__
+/* Pre-2.97 GCC did not support C99 flexible arrays but did have
+   an equivalent extension with slightly different notation.  */
+# define __flexarr	[0]
+# define __glibc_c99_flexarr_available 1
+#else
+/* Some other non-C99 compiler.  Approximate with [1].  */
+# define __flexarr	[1]
+# define __glibc_c99_flexarr_available 0
+#endif
+
+
+/* __asm__ ("xyz") is used throughout the headers to rename functions
+   at the assembly language level.  This is wrapped by the __REDIRECT
+   macro, in order to support compilers that can do this some other
+   way.  When compilers don't support asm-names at all, we have to do
+   preprocessor tricks instead (which don't have exactly the right
+   semantics, but it's the best we can do).
+
+   Example:
+   int __REDIRECT(setpgrp, (__pid_t pid, __pid_t pgrp), setpgid); */
+
+#if (defined __GNUC__ && __GNUC__ >= 2) || (__clang_major__ >= 4)
+
+# define __REDIRECT(name, proto, alias) name proto __asm__ (__ASMNAME (#alias))
+# ifdef __cplusplus
+#  define __REDIRECT_NTH(name, proto, alias) \
+     name proto __THROW __asm__ (__ASMNAME (#alias))
+#  define __REDIRECT_NTHNL(name, proto, alias) \
+     name proto __THROWNL __asm__ (__ASMNAME (#alias))
+# else
+#  define __REDIRECT_NTH(name, proto, alias) \
+     name proto __asm__ (__ASMNAME (#alias)) __THROW
+#  define __REDIRECT_NTHNL(name, proto, alias) \
+     name proto __asm__ (__ASMNAME (#alias)) __THROWNL
+# endif
+# define __ASMNAME(cname)  __ASMNAME2 (__USER_LABEL_PREFIX__, cname)
+# define __ASMNAME2(prefix, cname) __STRING (prefix) cname
+
+/*
+#elif __SOME_OTHER_COMPILER__
+
+# define __REDIRECT(name, proto, alias) name proto; \
+	_Pragma("let " #name " = " #alias)
+*/
+#endif
+
+/* GCC and clang have various useful declarations that can be made with
+   the '__attribute__' syntax.  All of the ways we use this do fine if
+   they are omitted for compilers that don't understand it.  */
+#if !(defined __GNUC__ || defined __clang__)
+# define __attribute__(xyz)	/* Ignore */
+#endif
+
+/* At some point during the gcc 2.96 development the `malloc' attribute
+   for functions was introduced.  We don't want to use it unconditionally
+   (although this would be possible) since it generates warnings.  */
+#if __GNUC_PREREQ (2,96) || __glibc_has_attribute (__malloc__)
+# define __attribute_malloc__ __attribute__ ((__malloc__))
+#else
+# define __attribute_malloc__ /* Ignore */
+#endif
+
+/* Tell the compiler which arguments to an allocation function
+   indicate the size of the allocation.  */
+#if __GNUC_PREREQ (4, 3)
+# define __attribute_alloc_size__(params) \
+  __attribute__ ((__alloc_size__ params))
+#else
+# define __attribute_alloc_size__(params) /* Ignore.  */
+#endif
+
+/* Tell the compiler which argument to an allocation function
+   indicates the alignment of the allocation.  */
+#if __GNUC_PREREQ (4, 9) || __glibc_has_attribute (__alloc_align__)
+# define __attribute_alloc_align__(param) \
+  __attribute__ ((__alloc_align__ param))
+#else
+# define __attribute_alloc_align__(param) /* Ignore.  */
+#endif
+
+/* At some point during the gcc 2.96 development the `pure' attribute
+   for functions was introduced.  We don't want to use it unconditionally
+   (although this would be possible) since it generates warnings.  */
+#if __GNUC_PREREQ (2,96) || __glibc_has_attribute (__pure__)
+# define __attribute_pure__ __attribute__ ((__pure__))
+#else
+# define __attribute_pure__ /* Ignore */
+#endif
+
+/* This declaration tells the compiler that the value is constant.  */
+#if __GNUC_PREREQ (2,5) || __glibc_has_attribute (__const__)
+# define __attribute_const__ __attribute__ ((__const__))
+#else
+# define __attribute_const__ /* Ignore */
+#endif
+
+#if __GNUC_PREREQ (2,7) || __glibc_has_attribute (__unused__)
+# define __attribute_maybe_unused__ __attribute__ ((__unused__))
+#else
+# define __attribute_maybe_unused__ /* Ignore */
+#endif
+
+/* At some point during the gcc 3.1 development the `used' attribute
+   for functions was introduced.  We don't want to use it unconditionally
+   (although this would be possible) since it generates warnings.  */
+#if __GNUC_PREREQ (3,1) || __glibc_has_attribute (__used__)
+# define __attribute_used__ __attribute__ ((__used__))
+# define __attribute_noinline__ __attribute__ ((__noinline__))
+#else
+# define __attribute_used__ __attribute__ ((__unused__))
+# define __attribute_noinline__ /* Ignore */
+#endif
+
+/* Since version 3.2, gcc allows marking deprecated functions.  */
+#if __GNUC_PREREQ (3,2) || __glibc_has_attribute (__deprecated__)
+# define __attribute_deprecated__ __attribute__ ((__deprecated__))
+#else
+# define __attribute_deprecated__ /* Ignore */
+#endif
+
+/* Since version 4.5, gcc also allows one to specify the message printed
+   when a deprecated function is used.  clang claims to be gcc 4.2, but
+   may also support this feature.  */
+#if __GNUC_PREREQ (4,5) \
+    || __glibc_has_extension (__attribute_deprecated_with_message__)
+# define __attribute_deprecated_msg__(msg) \
+	 __attribute__ ((__deprecated__ (msg)))
+#else
+# define __attribute_deprecated_msg__(msg) __attribute_deprecated__
+#endif
+
+/* At some point during the gcc 2.8 development the `format_arg' attribute
+   for functions was introduced.  We don't want to use it unconditionally
+   (although this would be possible) since it generates warnings.
+   If several `format_arg' attributes are given for the same function, in
+   gcc-3.0 and older, all but the last one are ignored.  In newer gccs,
+   all designated arguments are considered.  */
+#if __GNUC_PREREQ (2,8) || __glibc_has_attribute (__format_arg__)
+# define __attribute_format_arg__(x) __attribute__ ((__format_arg__ (x)))
+#else
+# define __attribute_format_arg__(x) /* Ignore */
+#endif
+
+/* At some point during the gcc 2.97 development the `strfmon' format
+   attribute for functions was introduced.  We don't want to use it
+   unconditionally (although this would be possible) since it
+   generates warnings.  */
+#if __GNUC_PREREQ (2,97) || __glibc_has_attribute (__format__)
+# define __attribute_format_strfmon__(a,b) \
+  __attribute__ ((__format__ (__strfmon__, a, b)))
+#else
+# define __attribute_format_strfmon__(a,b) /* Ignore */
+#endif
+
+/* The nonnull function attribute marks pointer parameters that
+   must not be NULL.  This has the name __nonnull in glibc,
+   and __attribute_nonnull__ in files shared with Gnulib to avoid
+   collision with a different __nonnull in DragonFlyBSD 5.9.  */
+#ifndef __attribute_nonnull__
+# if __GNUC_PREREQ (3,3) || __glibc_has_attribute (__nonnull__)
+#  define __attribute_nonnull__(params) __attribute__ ((__nonnull__ params))
+# else
+#  define __attribute_nonnull__(params)
+# endif
+#endif
+#ifndef __nonnull
+# define __nonnull(params) __attribute_nonnull__ (params)
+#endif
+
+/* The returns_nonnull function attribute marks the return type of the function
+   as always being non-null.  */
+#ifndef __returns_nonnull
+# if __GNUC_PREREQ (4, 9) || __glibc_has_attribute (__returns_nonnull__)
+# define __returns_nonnull __attribute__ ((__returns_nonnull__))
+# else
+# define __returns_nonnull
+# endif
+#endif
+
+/* If fortification mode, we warn about unused results of certain
+   function calls which can lead to problems.  */
+#if __GNUC_PREREQ (3,4) || __glibc_has_attribute (__warn_unused_result__)
+# define __attribute_warn_unused_result__ \
+   __attribute__ ((__warn_unused_result__))
+# if defined __USE_FORTIFY_LEVEL && __USE_FORTIFY_LEVEL > 0
+#  define __wur __attribute_warn_unused_result__
+# endif
+#else
+# define __attribute_warn_unused_result__ /* empty */
+#endif
+#ifndef __wur
+# define __wur /* Ignore */
+#endif
+
+/* Forces a function to be always inlined.  */
+#if __GNUC_PREREQ (3,2) || __glibc_has_attribute (__always_inline__)
+/* The Linux kernel defines __always_inline in stddef.h (283d7573), and
+   it conflicts with this definition.  Therefore undefine it first to
+   allow either header to be included first.  */
+# undef __always_inline
+# define __always_inline __inline __attribute__ ((__always_inline__))
+#else
+# undef __always_inline
+# define __always_inline __inline
+#endif
+
+/* Associate error messages with the source location of the call site rather
+   than with the source location inside the function.  */
+#if __GNUC_PREREQ (4,3) || __glibc_has_attribute (__artificial__)
+# define __attribute_artificial__ __attribute__ ((__artificial__))
+#else
+# define __attribute_artificial__ /* Ignore */
+#endif
+
+/* GCC 4.3 and above with -std=c99 or -std=gnu99 implements ISO C99
+   inline semantics, unless -fgnu89-inline is used.  Using __GNUC_STDC_INLINE__
+   or __GNUC_GNU_INLINE is not a good enough check for gcc because gcc versions
+   older than 4.3 may define these macros and still not guarantee GNU inlining
+   semantics.
+
+   clang++ identifies itself as gcc-4.2, but has support for GNU inlining
+   semantics, that can be checked for by using the __GNUC_STDC_INLINE_ and
+   __GNUC_GNU_INLINE__ macro definitions.  */
+#if (!defined __cplusplus || __GNUC_PREREQ (4,3) \
+     || (defined __clang__ && (defined __GNUC_STDC_INLINE__ \
+			       || defined __GNUC_GNU_INLINE__)))
+# if defined __GNUC_STDC_INLINE__ || defined __cplusplus
+#  define __extern_inline extern __inline __attribute__ ((__gnu_inline__))
+#  define __extern_always_inline \
+  extern __always_inline __attribute__ ((__gnu_inline__))
+# else
+#  define __extern_inline extern __inline
+#  define __extern_always_inline extern __always_inline
+# endif
+#endif
+
+#ifdef __extern_always_inline
+# define __fortify_function __extern_always_inline __attribute_artificial__
+#endif
+
+/* GCC 4.3 and above allow passing all anonymous arguments of an
+   __extern_always_inline function to some other vararg function.  */
+#if __GNUC_PREREQ (4,3)
+# define __va_arg_pack() __builtin_va_arg_pack ()
+# define __va_arg_pack_len() __builtin_va_arg_pack_len ()
+#endif
+
+/* It is possible to compile containing GCC extensions even if GCC is
+   run in pedantic mode if the uses are carefully marked using the
+   `__extension__' keyword.  But this is not generally available before
+   version 2.8.  */
+#if !(__GNUC_PREREQ (2,8) || defined __clang__)
+# define __extension__		/* Ignore */
+#endif
+
+/* __restrict is known in EGCS 1.2 and above, and in clang.
+   It works also in C++ mode (outside of arrays), but only when spelled
+   as '__restrict', not 'restrict'.  */
+#if !(__GNUC_PREREQ (2,92) || __clang_major__ >= 3)
+# if defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L
+#  define __restrict	restrict
+# else
+#  define __restrict	/* Ignore */
+# endif
+#endif
+
+/* ISO C99 also allows to declare arrays as non-overlapping.  The syntax is
+     array_name[restrict]
+   GCC 3.1 and clang support this.
+   This syntax is not usable in C++ mode.  */
+#if (__GNUC_PREREQ (3,1) || __clang_major__ >= 3) && !defined __cplusplus
+# define __restrict_arr	__restrict
+#else
+# ifdef __GNUC__
+#  define __restrict_arr	/* Not supported in old GCC.  */
+# else
+#  if defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L
+#   define __restrict_arr	restrict
+#  else
+/* Some other non-C99 compiler.  */
+#   define __restrict_arr	/* Not supported.  */
+#  endif
+# endif
+#endif
+
+#if (__GNUC__ >= 3) || __glibc_has_builtin (__builtin_expect)
+# define __glibc_unlikely(cond)	__builtin_expect ((cond), 0)
+# define __glibc_likely(cond)	__builtin_expect ((cond), 1)
+#else
+# define __glibc_unlikely(cond)	(cond)
+# define __glibc_likely(cond)	(cond)
+#endif
+
+#if (!defined _Noreturn \
+     && (defined __STDC_VERSION__ ? __STDC_VERSION__ : 0) < 201112 \
+     &&  !(__GNUC_PREREQ (4,7) \
+           || (3 < __clang_major__ + (5 <= __clang_minor__))))
+# if __GNUC_PREREQ (2,8)
+#  define _Noreturn __attribute__ ((__noreturn__))
+# else
+#  define _Noreturn
+# endif
+#endif
+
+#if __GNUC_PREREQ (8, 0)
+/* Describes a char array whose address can safely be passed as the first
+   argument to strncpy and strncat, as the char array is not necessarily
+   a NUL-terminated string.  */
+# define __attribute_nonstring__ __attribute__ ((__nonstring__))
+#else
+# define __attribute_nonstring__
+#endif
+
+/* Undefine (also defined in libc-symbols.h).  */
+#undef __attribute_copy__
+#if __GNUC_PREREQ (9, 0)
+/* Copies attributes from the declaration or type referenced by
+   the argument.  */
+# define __attribute_copy__(arg) __attribute__ ((__copy__ (arg)))
+#else
+# define __attribute_copy__(arg)
+#endif
+
+#if (!defined _Static_assert && !defined __cplusplus \
+     && (defined __STDC_VERSION__ ? __STDC_VERSION__ : 0) < 201112 \
+     && (!(__GNUC_PREREQ (4, 6) || __clang_major__ >= 4) \
+         || defined __STRICT_ANSI__))
+# define _Static_assert(expr, diagnostic) \
+    extern int (*__Static_assert_function (void)) \
+      [!!sizeof (struct { int __error_if_negative: (expr) ? 2 : -1; })]
+#endif
+
+/* Gnulib avoids including these, as they don't work on non-glibc or
+   older glibc platforms.  */
+#ifndef __GNULIB_CDEFS
+# include <bits/wordsize.h>
+# include <bits/long-double.h>
+#endif
+
+#if __LDOUBLE_REDIRECTS_TO_FLOAT128_ABI == 1
+# ifdef __REDIRECT
+
+/* Alias name defined automatically.  */
+#  define __LDBL_REDIR(name, proto) ... unused__ldbl_redir
+#  define __LDBL_REDIR_DECL(name) \
+  extern __typeof (name) name __asm (__ASMNAME ("__" #name "ieee128"));
+
+/* Alias name defined automatically, with leading underscores.  */
+#  define __LDBL_REDIR2_DECL(name) \
+  extern __typeof (__##name) __##name \
+    __asm (__ASMNAME ("__" #name "ieee128"));
+
+/* Alias name defined manually.  */
+#  define __LDBL_REDIR1(name, proto, alias) ... unused__ldbl_redir1
+#  define __LDBL_REDIR1_DECL(name, alias) \
+  extern __typeof (name) name __asm (__ASMNAME (#alias));
+
+#  define __LDBL_REDIR1_NTH(name, proto, alias) \
+  __REDIRECT_NTH (name, proto, alias)
+#  define __REDIRECT_NTH_LDBL(name, proto, alias) \
+  __LDBL_REDIR1_NTH (name, proto, __##alias##ieee128)
+
+/* Unused.  */
+#  define __REDIRECT_LDBL(name, proto, alias) ... unused__redirect_ldbl
+#  define __LDBL_REDIR_NTH(name, proto) ... unused__ldbl_redir_nth
+
+# else
+_Static_assert (0, "IEEE 128-bits long double requires redirection on this platform");
+# endif
+#elif defined __LONG_DOUBLE_MATH_OPTIONAL && defined __NO_LONG_DOUBLE_MATH
+# define __LDBL_COMPAT 1
+# ifdef __REDIRECT
+#  define __LDBL_REDIR1(name, proto, alias) __REDIRECT (name, proto, alias)
+#  define __LDBL_REDIR(name, proto) \
+  __LDBL_REDIR1 (name, proto, __nldbl_##name)
+#  define __LDBL_REDIR1_NTH(name, proto, alias) __REDIRECT_NTH (name, proto, alias)
+#  define __LDBL_REDIR_NTH(name, proto) \
+  __LDBL_REDIR1_NTH (name, proto, __nldbl_##name)
+#  define __LDBL_REDIR2_DECL(name) \
+  extern __typeof (__##name) __##name __asm (__ASMNAME ("__nldbl___" #name));
+#  define __LDBL_REDIR1_DECL(name, alias) \
+  extern __typeof (name) name __asm (__ASMNAME (#alias));
+#  define __LDBL_REDIR_DECL(name) \
+  extern __typeof (name) name __asm (__ASMNAME ("__nldbl_" #name));
+#  define __REDIRECT_LDBL(name, proto, alias) \
+  __LDBL_REDIR1 (name, proto, __nldbl_##alias)
+#  define __REDIRECT_NTH_LDBL(name, proto, alias) \
+  __LDBL_REDIR1_NTH (name, proto, __nldbl_##alias)
+# endif
+#endif
+#if (!defined __LDBL_COMPAT && __LDOUBLE_REDIRECTS_TO_FLOAT128_ABI == 0) \
+    || !defined __REDIRECT
+# define __LDBL_REDIR1(name, proto, alias) name proto
+# define __LDBL_REDIR(name, proto) name proto
+# define __LDBL_REDIR1_NTH(name, proto, alias) name proto __THROW
+# define __LDBL_REDIR_NTH(name, proto) name proto __THROW
+# define __LDBL_REDIR2_DECL(name)
+# define __LDBL_REDIR_DECL(name)
+# ifdef __REDIRECT
+#  define __REDIRECT_LDBL(name, proto, alias) __REDIRECT (name, proto, alias)
+#  define __REDIRECT_NTH_LDBL(name, proto, alias) \
+  __REDIRECT_NTH (name, proto, alias)
+# endif
+#endif
+
+/* __glibc_macro_warning (MESSAGE) issues warning MESSAGE.  This is
+   intended for use in preprocessor macros.
+
+   Note: MESSAGE must be a _single_ string; concatenation of string
+   literals is not supported.  */
+#if __GNUC_PREREQ (4,8) || __glibc_clang_prereq (3,5)
+# define __glibc_macro_warning1(message) _Pragma (#message)
+# define __glibc_macro_warning(message) \
+  __glibc_macro_warning1 (GCC warning message)
+#else
+# define __glibc_macro_warning(msg)
+#endif
+
+/* Generic selection (ISO C11) is a C-only feature, available in GCC
+   since version 4.9.  Previous versions do not provide generic
+   selection, even though they might set __STDC_VERSION__ to 201112L,
+   when in -std=c11 mode.  Thus, we must check for !defined __GNUC__
+   when testing __STDC_VERSION__ for generic selection support.
+   On the other hand, Clang also defines __GNUC__, so a clang-specific
+   check is required to enable the use of generic selection.  */
+#if !defined __cplusplus \
+    && (__GNUC_PREREQ (4, 9) \
+	|| __glibc_has_extension (c_generic_selections) \
+	|| (!defined __GNUC__ && defined __STDC_VERSION__ \
+	    && __STDC_VERSION__ >= 201112L))
+# define __HAVE_GENERIC_SELECTION 1
+#else
+# define __HAVE_GENERIC_SELECTION 0
+#endif
+
+#if __GNUC_PREREQ (10, 0)
+/* Designates a 1-based positional argument ref-index of pointer type
+   that can be used to access size-index elements of the pointed-to
+   array according to access mode, or at least one element when
+   size-index is not provided:
+     access (access-mode, <ref-index> [, <size-index>])  */
+#  define __attr_access(x) __attribute__ ((__access__ x))
+/* For _FORTIFY_SOURCE == 3 we use __builtin_dynamic_object_size, which may
+   use the access attribute to get object sizes from function definition
+   arguments, so we can't use them on functions we fortify.  Drop the object
+   size hints for such functions.  */
+#  if __USE_FORTIFY_LEVEL == 3
+#    define __fortified_attr_access(a, o, s) __attribute__ ((__access__ (a, o)))
+#  else
+#    define __fortified_attr_access(a, o, s) __attr_access ((a, o, s))
+#  endif
+#  if __GNUC_PREREQ (11, 0)
+#    define __attr_access_none(argno) __attribute__ ((__access__ (__none__, argno)))
+#  else
+#    define __attr_access_none(argno)
+#  endif
+#else
+#  define __fortified_attr_access(a, o, s)
+#  define __attr_access(x)
+#  define __attr_access_none(argno)
+#endif
+
+#if __GNUC_PREREQ (11, 0)
+/* Designates dealloc as a function to call to deallocate objects
+   allocated by the declared function.  */
+# define __attr_dealloc(dealloc, argno) \
+    __attribute__ ((__malloc__ (dealloc, argno)))
+# define __attr_dealloc_free __attr_dealloc (__builtin_free, 1)
+#else
+# define __attr_dealloc(dealloc, argno)
+# define __attr_dealloc_free
+#endif
+
+/* Specify that a function such as setjmp or vfork may return
+   twice.  */
+#if __GNUC_PREREQ (4, 1)
+# define __attribute_returns_twice__ __attribute__ ((__returns_twice__))
+#else
+# define __attribute_returns_twice__ /* Ignore.  */
+#endif
+
+#endif	 /* sys/cdefs.h */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@sys@cdefs.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@sys@cdefs.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@sys@select.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@sys@select.h
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@sys@select.h
@@ -0,0 +1,155 @@
+/* `fd_set' type and related macros, and `select'/`pselect' declarations.
+   Copyright (C) 1996-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+/*	POSIX 1003.1g: 6.2 Select from File Descriptor Sets <sys/select.h>  */
+
+#ifndef _SYS_SELECT_H
+#define _SYS_SELECT_H	1
+
+#include <features.h>
+
+/* Get definition of needed basic types.  */
+#include <bits/types.h>
+
+/* Get __FD_* definitions.  */
+#include <bits/select.h>
+
+/* Get sigset_t.  */
+#include <bits/types/sigset_t.h>
+
+/* Get definition of timer specification structures.  */
+#include <bits/types/time_t.h>
+#include <bits/types/struct_timeval.h>
+#ifdef __USE_XOPEN2K
+# include <bits/types/struct_timespec.h>
+#endif
+
+#ifndef __suseconds_t_defined
+typedef __suseconds_t suseconds_t;
+# define __suseconds_t_defined
+#endif
+
+
+/* The fd_set member is required to be an array of longs.  */
+typedef long int __fd_mask;
+
+/* Some versions of <linux/posix_types.h> define this macros.  */
+#undef	__NFDBITS
+/* It's easier to assume 8-bit bytes than to get CHAR_BIT.  */
+#define __NFDBITS	(8 * (int) sizeof (__fd_mask))
+#define	__FD_ELT(d)	((d) / __NFDBITS)
+#define	__FD_MASK(d)	((__fd_mask) (1UL << ((d) % __NFDBITS)))
+
+/* fd_set for select and pselect.  */
+typedef struct
+  {
+    /* XPG4.2 requires this member name.  Otherwise avoid the name
+       from the global namespace.  */
+#ifdef __USE_XOPEN
+    __fd_mask fds_bits[__FD_SETSIZE / __NFDBITS];
+# define __FDS_BITS(set) ((set)->fds_bits)
+#else
+    __fd_mask __fds_bits[__FD_SETSIZE / __NFDBITS];
+# define __FDS_BITS(set) ((set)->__fds_bits)
+#endif
+  } fd_set;
+
+/* Maximum number of file descriptors in `fd_set'.  */
+#define	FD_SETSIZE		__FD_SETSIZE
+
+#ifdef __USE_MISC
+/* Sometimes the fd_set member is assumed to have this type.  */
+typedef __fd_mask fd_mask;
+
+/* Number of bits per word of `fd_set' (some code assumes this is 32).  */
+# define NFDBITS		__NFDBITS
+#endif
+
+
+/* Access macros for `fd_set'.  */
+#define	FD_SET(fd, fdsetp)	__FD_SET (fd, fdsetp)
+#define	FD_CLR(fd, fdsetp)	__FD_CLR (fd, fdsetp)
+#define	FD_ISSET(fd, fdsetp)	__FD_ISSET (fd, fdsetp)
+#define	FD_ZERO(fdsetp)		__FD_ZERO (fdsetp)
+
+
+__BEGIN_DECLS
+
+/* Check the first NFDS descriptors each in READFDS (if not NULL) for read
+   readiness, in WRITEFDS (if not NULL) for write readiness, and in EXCEPTFDS
+   (if not NULL) for exceptional conditions.  If TIMEOUT is not NULL, time out
+   after waiting the interval specified therein.  Returns the number of ready
+   descriptors, or -1 for errors.
+
+   This function is a cancellation point and therefore not marked with
+   __THROW.  */
+#ifndef __USE_TIME_BITS64
+extern int select (int __nfds, fd_set *__restrict __readfds,
+		   fd_set *__restrict __writefds,
+		   fd_set *__restrict __exceptfds,
+		   struct timeval *__restrict __timeout);
+#else
+# ifdef __REDIRECT
+extern int __REDIRECT (select,
+                       (int __nfds, fd_set *__restrict __readfds,
+                        fd_set *__restrict __writefds,
+                        fd_set *__restrict __exceptfds,
+                        struct timeval *__restrict __timeout),
+                       __select64);
+# else
+#  define select __select64
+# endif
+#endif
+
+#ifdef __USE_XOPEN2K
+/* Same as above only that the TIMEOUT value is given with higher
+   resolution and a sigmask which is been set temporarily.  This version
+   should be used.
+
+   This function is a cancellation point and therefore not marked with
+   __THROW.  */
+# ifndef __USE_TIME_BITS64
+extern int pselect (int __nfds, fd_set *__restrict __readfds,
+		    fd_set *__restrict __writefds,
+		    fd_set *__restrict __exceptfds,
+		    const struct timespec *__restrict __timeout,
+		    const __sigset_t *__restrict __sigmask);
+# else
+#  ifdef __REDIRECT
+extern int __REDIRECT (pselect,
+                       (int __nfds, fd_set *__restrict __readfds,
+                        fd_set *__restrict __writefds,
+                        fd_set *__restrict __exceptfds,
+                        const struct timespec *__restrict __timeout,
+                        const __sigset_t *__restrict __sigmask),
+                       __pselect64);
+#  else
+#   define pselect __pselect64
+#  endif
+# endif
+#endif
+
+
+/* Define some inlines helping to catch common problems.  */
+#if __USE_FORTIFY_LEVEL > 0 && defined __GNUC__
+# include <bits/select2.h>
+#endif
+
+__END_DECLS
+
+#endif /* sys/select.h */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@sys@select.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@sys@select.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@sys@single_threaded.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@sys@single_threaded.h
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index 0000000000000000000000000000000000000000..191d6116a1f1ec5a73e9fcebb1379d4d0c12441a
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@sys@single_threaded.h
@@ -0,0 +1,33 @@
+/* Support for single-thread optimizations.
+   Copyright (C) 2020-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _SYS_SINGLE_THREADED_H
+#define _SYS_SINGLE_THREADED_H
+
+#include <features.h>
+
+__BEGIN_DECLS
+
+/* If this variable is non-zero, then the current thread is the only
+   thread in the process image.  If it is zero, the process might be
+   multi-threaded.  */
+extern char __libc_single_threaded;
+
+__END_DECLS
+
+#endif /* _SYS_SINGLE_THREADED_H */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@sys@single_threaded.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@sys@single_threaded.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@sys@types.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@sys@types.h
new file mode 100644
index 0000000000000000000000000000000000000000..bb76babbaf21596667d9840b60bf743771a21555
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@sys@types.h
@@ -0,0 +1,232 @@
+/* Copyright (C) 1991-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+/*
+ *	POSIX Standard: 2.6 Primitive System Data Types	<sys/types.h>
+ */
+
+#ifndef	_SYS_TYPES_H
+#define	_SYS_TYPES_H	1
+
+#include <features.h>
+
+__BEGIN_DECLS
+
+#include <bits/types.h>
+
+#ifdef	__USE_MISC
+# ifndef __u_char_defined
+typedef __u_char u_char;
+typedef __u_short u_short;
+typedef __u_int u_int;
+typedef __u_long u_long;
+typedef __quad_t quad_t;
+typedef __u_quad_t u_quad_t;
+typedef __fsid_t fsid_t;
+#  define __u_char_defined
+# endif
+typedef __loff_t loff_t;
+#endif
+
+#ifndef __ino_t_defined
+# ifndef __USE_FILE_OFFSET64
+typedef __ino_t ino_t;
+# else
+typedef __ino64_t ino_t;
+# endif
+# define __ino_t_defined
+#endif
+#if defined __USE_LARGEFILE64 && !defined __ino64_t_defined
+typedef __ino64_t ino64_t;
+# define __ino64_t_defined
+#endif
+
+#ifndef __dev_t_defined
+typedef __dev_t dev_t;
+# define __dev_t_defined
+#endif
+
+#ifndef __gid_t_defined
+typedef __gid_t gid_t;
+# define __gid_t_defined
+#endif
+
+#ifndef __mode_t_defined
+typedef __mode_t mode_t;
+# define __mode_t_defined
+#endif
+
+#ifndef __nlink_t_defined
+typedef __nlink_t nlink_t;
+# define __nlink_t_defined
+#endif
+
+#ifndef __uid_t_defined
+typedef __uid_t uid_t;
+# define __uid_t_defined
+#endif
+
+#ifndef __off_t_defined
+# ifndef __USE_FILE_OFFSET64
+typedef __off_t off_t;
+# else
+typedef __off64_t off_t;
+# endif
+# define __off_t_defined
+#endif
+#if defined __USE_LARGEFILE64 && !defined __off64_t_defined
+typedef __off64_t off64_t;
+# define __off64_t_defined
+#endif
+
+#ifndef __pid_t_defined
+typedef __pid_t pid_t;
+# define __pid_t_defined
+#endif
+
+#if (defined __USE_XOPEN || defined __USE_XOPEN2K8) \
+    && !defined __id_t_defined
+typedef __id_t id_t;
+# define __id_t_defined
+#endif
+
+#ifndef __ssize_t_defined
+typedef __ssize_t ssize_t;
+# define __ssize_t_defined
+#endif
+
+#ifdef	__USE_MISC
+# ifndef __daddr_t_defined
+typedef __daddr_t daddr_t;
+typedef __caddr_t caddr_t;
+#  define __daddr_t_defined
+# endif
+#endif
+
+#if (defined __USE_MISC || defined __USE_XOPEN) && !defined __key_t_defined
+typedef __key_t key_t;
+# define __key_t_defined
+#endif
+
+#if defined __USE_XOPEN || defined __USE_XOPEN2K8
+# include <bits/types/clock_t.h>
+#endif
+#include <bits/types/clockid_t.h>
+#include <bits/types/time_t.h>
+#include <bits/types/timer_t.h>
+
+#ifdef __USE_XOPEN
+# ifndef __useconds_t_defined
+typedef __useconds_t useconds_t;
+#  define __useconds_t_defined
+# endif
+# ifndef __suseconds_t_defined
+typedef __suseconds_t suseconds_t;
+#  define __suseconds_t_defined
+# endif
+#endif
+
+#define	__need_size_t
+#include <stddef.h>
+
+#ifdef __USE_MISC
+/* Old compatibility names for C types.  */
+typedef unsigned long int ulong;
+typedef unsigned short int ushort;
+typedef unsigned int uint;
+#endif
+
+/* These size-specific names are used by some of the inet code.  */
+
+#include <bits/stdint-intn.h>
+
+/* These were defined by ISO C without the first `_'.  */
+typedef __uint8_t u_int8_t;
+typedef __uint16_t u_int16_t;
+typedef __uint32_t u_int32_t;
+typedef __uint64_t u_int64_t;
+
+#if __GNUC_PREREQ (2, 7)
+typedef int register_t __attribute__ ((__mode__ (__word__)));
+#else
+typedef int register_t;
+#endif
+
+/* Some code from BIND tests this macro to see if the types above are
+   defined.  */
+#define __BIT_TYPES_DEFINED__	1
+
+
+#ifdef	__USE_MISC
+/* In BSD <sys/types.h> is expected to define BYTE_ORDER.  */
+# include <endian.h>
+
+/* It also defines `fd_set' and the FD_* macros for `select'.  */
+# include <sys/select.h>
+#endif /* Use misc.  */
+
+
+#if (defined __USE_UNIX98 || defined __USE_XOPEN2K8) \
+    && !defined __blksize_t_defined
+typedef __blksize_t blksize_t;
+# define __blksize_t_defined
+#endif
+
+/* Types from the Large File Support interface.  */
+#ifndef __USE_FILE_OFFSET64
+# ifndef __blkcnt_t_defined
+typedef __blkcnt_t blkcnt_t;	 /* Type to count number of disk blocks.  */
+#  define __blkcnt_t_defined
+# endif
+# ifndef __fsblkcnt_t_defined
+typedef __fsblkcnt_t fsblkcnt_t; /* Type to count file system blocks.  */
+#  define __fsblkcnt_t_defined
+# endif
+# ifndef __fsfilcnt_t_defined
+typedef __fsfilcnt_t fsfilcnt_t; /* Type to count file system inodes.  */
+#  define __fsfilcnt_t_defined
+# endif
+#else
+# ifndef __blkcnt_t_defined
+typedef __blkcnt64_t blkcnt_t;	   /* Type to count number of disk blocks.  */
+#  define __blkcnt_t_defined
+# endif
+# ifndef __fsblkcnt_t_defined
+typedef __fsblkcnt64_t fsblkcnt_t; /* Type to count file system blocks.  */
+#  define __fsblkcnt_t_defined
+# endif
+# ifndef __fsfilcnt_t_defined
+typedef __fsfilcnt64_t fsfilcnt_t; /* Type to count file system inodes.  */
+#  define __fsfilcnt_t_defined
+# endif
+#endif
+
+#ifdef __USE_LARGEFILE64
+typedef __blkcnt64_t blkcnt64_t;     /* Type to count number of disk blocks. */
+typedef __fsblkcnt64_t fsblkcnt64_t; /* Type to count file system blocks.  */
+typedef __fsfilcnt64_t fsfilcnt64_t; /* Type to count file system inodes.  */
+#endif
+
+
+/* Now add the thread types.  */
+#if defined __USE_POSIX199506 || defined __USE_UNIX98
+# include <bits/pthreadtypes.h>
+#endif
+
+__END_DECLS
+
+#endif /* sys/types.h */
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@sys@ucontext.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@sys@ucontext.h
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index 0000000000000000000000000000000000000000..81db73c2b58e8f5a1073f932e08044238ac1ae3a
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@sys@ucontext.h
@@ -0,0 +1,262 @@
+/* Copyright (C) 2001-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _SYS_UCONTEXT_H
+#define _SYS_UCONTEXT_H	1
+
+#include <features.h>
+
+#include <bits/types.h>
+#include <bits/types/sigset_t.h>
+#include <bits/types/stack_t.h>
+
+
+#ifdef __USE_MISC
+# define __ctx(fld) fld
+#else
+# define __ctx(fld) __ ## fld
+#endif
+
+#ifdef __x86_64__
+
+/* Type for general register.  */
+__extension__ typedef long long int greg_t;
+
+/* Number of general registers.  */
+#define __NGREG	23
+#ifdef __USE_MISC
+# define NGREG	__NGREG
+#endif
+
+/* Container for all general registers.  */
+typedef greg_t gregset_t[__NGREG];
+
+#ifdef __USE_GNU
+/* Number of each register in the `gregset_t' array.  */
+enum
+{
+  REG_R8 = 0,
+# define REG_R8		REG_R8
+  REG_R9,
+# define REG_R9		REG_R9
+  REG_R10,
+# define REG_R10	REG_R10
+  REG_R11,
+# define REG_R11	REG_R11
+  REG_R12,
+# define REG_R12	REG_R12
+  REG_R13,
+# define REG_R13	REG_R13
+  REG_R14,
+# define REG_R14	REG_R14
+  REG_R15,
+# define REG_R15	REG_R15
+  REG_RDI,
+# define REG_RDI	REG_RDI
+  REG_RSI,
+# define REG_RSI	REG_RSI
+  REG_RBP,
+# define REG_RBP	REG_RBP
+  REG_RBX,
+# define REG_RBX	REG_RBX
+  REG_RDX,
+# define REG_RDX	REG_RDX
+  REG_RAX,
+# define REG_RAX	REG_RAX
+  REG_RCX,
+# define REG_RCX	REG_RCX
+  REG_RSP,
+# define REG_RSP	REG_RSP
+  REG_RIP,
+# define REG_RIP	REG_RIP
+  REG_EFL,
+# define REG_EFL	REG_EFL
+  REG_CSGSFS,		/* Actually short cs, gs, fs, __pad0.  */
+# define REG_CSGSFS	REG_CSGSFS
+  REG_ERR,
+# define REG_ERR	REG_ERR
+  REG_TRAPNO,
+# define REG_TRAPNO	REG_TRAPNO
+  REG_OLDMASK,
+# define REG_OLDMASK	REG_OLDMASK
+  REG_CR2
+# define REG_CR2	REG_CR2
+};
+#endif
+
+struct _libc_fpxreg
+{
+  unsigned short int __ctx(significand)[4];
+  unsigned short int __ctx(exponent);
+  unsigned short int __glibc_reserved1[3];
+};
+
+struct _libc_xmmreg
+{
+  __uint32_t	__ctx(element)[4];
+};
+
+struct _libc_fpstate
+{
+  /* 64-bit FXSAVE format.  */
+  __uint16_t		__ctx(cwd);
+  __uint16_t		__ctx(swd);
+  __uint16_t		__ctx(ftw);
+  __uint16_t		__ctx(fop);
+  __uint64_t		__ctx(rip);
+  __uint64_t		__ctx(rdp);
+  __uint32_t		__ctx(mxcsr);
+  __uint32_t		__ctx(mxcr_mask);
+  struct _libc_fpxreg	_st[8];
+  struct _libc_xmmreg	_xmm[16];
+  __uint32_t		__glibc_reserved1[24];
+};
+
+/* Structure to describe FPU registers.  */
+typedef struct _libc_fpstate *fpregset_t;
+
+/* Context to describe whole processor state.  */
+typedef struct
+  {
+    gregset_t __ctx(gregs);
+    /* Note that fpregs is a pointer.  */
+    fpregset_t __ctx(fpregs);
+    __extension__ unsigned long long __reserved1 [8];
+} mcontext_t;
+
+/* Userlevel context.  */
+typedef struct ucontext_t
+  {
+    unsigned long int __ctx(uc_flags);
+    struct ucontext_t *uc_link;
+    stack_t uc_stack;
+    mcontext_t uc_mcontext;
+    sigset_t uc_sigmask;
+    struct _libc_fpstate __fpregs_mem;
+    __extension__ unsigned long long int __ssp[4];
+  } ucontext_t;
+
+#else /* !__x86_64__ */
+
+/* Type for general register.  */
+typedef int greg_t;
+
+/* Number of general registers.  */
+#define __NGREG	19
+#ifdef __USE_MISC
+# define NGREG	__NGREG
+#endif
+
+/* Container for all general registers.  */
+typedef greg_t gregset_t[__NGREG];
+
+#ifdef __USE_GNU
+/* Number of each register is the `gregset_t' array.  */
+enum
+{
+  REG_GS = 0,
+# define REG_GS		REG_GS
+  REG_FS,
+# define REG_FS		REG_FS
+  REG_ES,
+# define REG_ES		REG_ES
+  REG_DS,
+# define REG_DS		REG_DS
+  REG_EDI,
+# define REG_EDI	REG_EDI
+  REG_ESI,
+# define REG_ESI	REG_ESI
+  REG_EBP,
+# define REG_EBP	REG_EBP
+  REG_ESP,
+# define REG_ESP	REG_ESP
+  REG_EBX,
+# define REG_EBX	REG_EBX
+  REG_EDX,
+# define REG_EDX	REG_EDX
+  REG_ECX,
+# define REG_ECX	REG_ECX
+  REG_EAX,
+# define REG_EAX	REG_EAX
+  REG_TRAPNO,
+# define REG_TRAPNO	REG_TRAPNO
+  REG_ERR,
+# define REG_ERR	REG_ERR
+  REG_EIP,
+# define REG_EIP	REG_EIP
+  REG_CS,
+# define REG_CS		REG_CS
+  REG_EFL,
+# define REG_EFL	REG_EFL
+  REG_UESP,
+# define REG_UESP	REG_UESP
+  REG_SS
+# define REG_SS	REG_SS
+};
+#endif
+
+/* Definitions taken from the kernel headers.  */
+struct _libc_fpreg
+{
+  unsigned short int __ctx(significand)[4];
+  unsigned short int __ctx(exponent);
+};
+
+struct _libc_fpstate
+{
+  unsigned long int __ctx(cw);
+  unsigned long int __ctx(sw);
+  unsigned long int __ctx(tag);
+  unsigned long int __ctx(ipoff);
+  unsigned long int __ctx(cssel);
+  unsigned long int __ctx(dataoff);
+  unsigned long int __ctx(datasel);
+  struct _libc_fpreg _st[8];
+  unsigned long int __ctx(status);
+};
+
+/* Structure to describe FPU registers.  */
+typedef struct _libc_fpstate *fpregset_t;
+
+/* Context to describe whole processor state.  */
+typedef struct
+  {
+    gregset_t __ctx(gregs);
+    /* Due to Linux's history we have to use a pointer here.  The SysV/i386
+       ABI requires a struct with the values.  */
+    fpregset_t __ctx(fpregs);
+    unsigned long int __ctx(oldmask);
+    unsigned long int __ctx(cr2);
+  } mcontext_t;
+
+/* Userlevel context.  */
+typedef struct ucontext_t
+  {
+    unsigned long int __ctx(uc_flags);
+    struct ucontext_t *uc_link;
+    stack_t uc_stack;
+    mcontext_t uc_mcontext;
+    sigset_t uc_sigmask;
+    struct _libc_fpstate __fpregs_mem;
+    unsigned long int __ssp[4];
+  } ucontext_t;
+
+#endif /* !__x86_64__ */
+
+#undef __ctx
+
+#endif /* sys/ucontext.h */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@sys@ucontext.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@sys@ucontext.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@time.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@time.h
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@@ -0,0 +1,442 @@
+/* Copyright (C) 1991-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+/*
+ *	ISO C99 Standard: 7.23 Date and time	<time.h>
+ */
+
+#ifndef	_TIME_H
+#define _TIME_H	1
+
+#include <features.h>
+
+#define __need_size_t
+#define __need_NULL
+#include <stddef.h>
+
+/* This defines CLOCKS_PER_SEC, which is the number of processor clock
+   ticks per second, and possibly a number of other constants.   */
+#include <bits/time.h>
+
+/* Many of the typedefs and structs whose official home is this header
+   may also need to be defined by other headers.  */
+#include <bits/types/clock_t.h>
+#include <bits/types/time_t.h>
+#include <bits/types/struct_tm.h>
+
+#if defined __USE_POSIX199309 || defined __USE_ISOC11
+# include <bits/types/struct_timespec.h>
+#endif
+
+#ifdef __USE_POSIX199309
+# include <bits/types/clockid_t.h>
+# include <bits/types/timer_t.h>
+# include <bits/types/struct_itimerspec.h>
+struct sigevent;
+#endif
+
+#ifdef __USE_XOPEN2K
+# ifndef __pid_t_defined
+typedef __pid_t pid_t;
+#  define __pid_t_defined
+# endif
+#endif
+
+#ifdef __USE_XOPEN2K8
+# include <bits/types/locale_t.h>
+#endif
+
+#ifdef __USE_ISOC11
+/* Time base values for timespec_get.  */
+# define TIME_UTC 1
+#endif
+
+__BEGIN_DECLS
+
+/* Time used by the program so far (user time + system time).
+   The result / CLOCKS_PER_SEC is program time in seconds.  */
+extern clock_t clock (void) __THROW;
+
+#ifndef __USE_TIME_BITS64
+/* Return the current time and put it in *TIMER if TIMER is not NULL.  */
+extern time_t time (time_t *__timer) __THROW;
+
+/* Return the difference between TIME1 and TIME0.  */
+extern double difftime (time_t __time1, time_t __time0)
+     __THROW __attribute__ ((__const__));
+
+/* Return the `time_t' representation of TP and normalize TP.  */
+extern time_t mktime (struct tm *__tp) __THROW;
+#else
+# ifdef __REDIRECT_NTH
+extern time_t __REDIRECT_NTH (time, (time_t *__timer), __time64);
+extern double __REDIRECT_NTH (difftime, (time_t __time1, time_t __time0),
+                              __difftime64) __attribute__ ((__const__));
+extern time_t __REDIRECT_NTH (mktime, (struct tm *__tp), __mktime64);
+# else
+#  define time __time64
+#  define difftime __difftime64
+#  define mktime __mktime64
+# endif
+#endif
+
+/* Format TP into S according to FORMAT.
+   Write no more than MAXSIZE characters and return the number
+   of characters written, or 0 if it would exceed MAXSIZE.  */
+extern size_t strftime (char *__restrict __s, size_t __maxsize,
+			const char *__restrict __format,
+			const struct tm *__restrict __tp) __THROW;
+
+#ifdef __USE_XOPEN
+/* Parse S according to FORMAT and store binary time information in TP.
+   The return value is a pointer to the first unparsed character in S.  */
+extern char *strptime (const char *__restrict __s,
+		       const char *__restrict __fmt, struct tm *__tp)
+     __THROW;
+#endif
+
+#ifdef __USE_XOPEN2K8
+/* Similar to the two functions above but take the information from
+   the provided locale and not the global locale.  */
+
+extern size_t strftime_l (char *__restrict __s, size_t __maxsize,
+			  const char *__restrict __format,
+			  const struct tm *__restrict __tp,
+			  locale_t __loc) __THROW;
+#endif
+
+#ifdef __USE_GNU
+extern char *strptime_l (const char *__restrict __s,
+			 const char *__restrict __fmt, struct tm *__tp,
+			 locale_t __loc) __THROW;
+#endif
+
+
+#ifndef __USE_TIME_BITS64
+/* Return the `struct tm' representation of *TIMER
+   in Universal Coordinated Time (aka Greenwich Mean Time).  */
+extern struct tm *gmtime (const time_t *__timer) __THROW;
+
+/* Return the `struct tm' representation
+   of *TIMER in the local timezone.  */
+extern struct tm *localtime (const time_t *__timer) __THROW;
+
+#else
+# ifdef __REDIRECT_NTH
+extern struct tm*__REDIRECT_NTH (gmtime, (const time_t *__timer), __gmtime64);
+extern struct tm *__REDIRECT_NTH (localtime, (const time_t *__timer),
+				  __localtime64);
+# else
+#  define gmtime __gmtime64
+#  define localtime __localtime64
+# endif
+#endif
+
+
+#if defined __USE_POSIX || __GLIBC_USE (ISOC2X)
+# ifndef __USE_TIME_BITS64
+/* Return the `struct tm' representation of *TIMER in UTC,
+   using *TP to store the result.  */
+extern struct tm *gmtime_r (const time_t *__restrict __timer,
+			    struct tm *__restrict __tp) __THROW;
+
+/* Return the `struct tm' representation of *TIMER in local time,
+   using *TP to store the result.  */
+extern struct tm *localtime_r (const time_t *__restrict __timer,
+			       struct tm *__restrict __tp) __THROW;
+# else
+#  ifdef __REDIRECT_NTH
+extern struct tm*__REDIRECT_NTH (gmtime_r, (const time_t *__restrict __timer,
+                                            struct tm *__restrict __tp),
+                                 __gmtime64_r);
+
+extern struct tm*__REDIRECT_NTH (localtime_r, (const time_t *__restrict __t,
+                                               struct tm *__restrict __tp),
+                                 __localtime64_r);
+#  else
+#   define gmtime_r __gmtime64_r
+#   define localtime_r __localtime_r
+#  endif
+# endif
+#endif	/* POSIX || C2X */
+
+/* Return a string of the form "Day Mon dd hh:mm:ss yyyy\n"
+   that is the representation of TP in this format.  */
+extern char *asctime (const struct tm *__tp) __THROW;
+
+/* Equivalent to `asctime (localtime (timer))'.  */
+#ifndef __USE_TIME_BITS64
+extern char *ctime (const time_t *__timer) __THROW;
+#else
+# ifdef __REDIRECT_NTH
+extern char *__REDIRECT_NTH (ctime, (const time_t *__timer), __ctime64);
+# else
+#  define ctime __ctime64
+# endif
+#endif
+
+#ifdef __USE_POSIX
+/* Reentrant versions of the above functions.  */
+
+/* Return in BUF a string of the form "Day Mon dd hh:mm:ss yyyy\n"
+   that is the representation of TP in this format.  */
+extern char *asctime_r (const struct tm *__restrict __tp,
+			char *__restrict __buf) __THROW;
+
+/* Equivalent to `asctime_r (localtime_r (timer, *TMP*), buf)'.  */
+#ifndef __USE_TIME_BITS64
+extern char *ctime_r (const time_t *__restrict __timer,
+		      char *__restrict __buf) __THROW;
+#else
+# ifdef __REDIRECT_NTH
+extern char *__REDIRECT_NTH (ctime_r, (const time_t *__restrict __timer,
+                                       char *__restrict __buf), __ctime64_r);
+# else
+#  define ctime_r __ctime64_r
+# endif
+#endif
+
+#endif	/* POSIX */
+
+
+/* Defined in localtime.c.  */
+extern char *__tzname[2];	/* Current timezone names.  */
+extern int __daylight;		/* If daylight-saving time is ever in use.  */
+extern long int __timezone;	/* Seconds west of UTC.  */
+
+
+#ifdef	__USE_POSIX
+/* Same as above.  */
+extern char *tzname[2];
+
+/* Set time conversion information from the TZ environment variable.
+   If TZ is not defined, a locale-dependent default is used.  */
+extern void tzset (void) __THROW;
+#endif
+
+#if defined __USE_MISC || defined __USE_XOPEN
+extern int daylight;
+extern long int timezone;
+#endif
+
+
+/* Nonzero if YEAR is a leap year (every 4 years,
+   except every 100th isn't, and every 400th is).  */
+#define __isleap(year)	\
+  ((year) % 4 == 0 && ((year) % 100 != 0 || (year) % 400 == 0))
+
+
+#ifdef __USE_MISC
+/* Miscellaneous functions many Unices inherited from the public domain
+   localtime package.  These are included only for compatibility.  */
+
+#ifndef __USE_TIME_BITS64
+/* Like `mktime', but for TP represents Universal Time, not local time.  */
+extern time_t timegm (struct tm *__tp) __THROW;
+/* Another name for `mktime'.  */
+extern time_t timelocal (struct tm *__tp) __THROW;
+#else
+# ifdef __REDIRECT_NTH
+extern time_t __REDIRECT_NTH (timegm, (struct tm *__tp), __timegm64);
+extern time_t __REDIRECT_NTH (timelocal, (struct tm *__tp), __mktime64);
+# else
+#  define timegm __timegm64
+# endif
+#endif
+
+/* Return the number of days in YEAR.  */
+extern int dysize (int __year) __THROW  __attribute__ ((__const__));
+#endif
+
+
+#ifdef __USE_POSIX199309
+# ifndef __USE_TIME_BITS64
+/* Pause execution for a number of nanoseconds.
+
+   This function is a cancellation point and therefore not marked with
+   __THROW.  */
+extern int nanosleep (const struct timespec *__requested_time,
+		      struct timespec *__remaining);
+
+/* Get resolution of clock CLOCK_ID.  */
+extern int clock_getres (clockid_t __clock_id, struct timespec *__res) __THROW;
+
+/* Get current value of clock CLOCK_ID and store it in TP.  */
+extern int clock_gettime (clockid_t __clock_id, struct timespec *__tp) __THROW;
+
+/* Set clock CLOCK_ID to value TP.  */
+extern int clock_settime (clockid_t __clock_id, const struct timespec *__tp)
+     __THROW;
+# else
+#  ifdef __REDIRECT
+extern int __REDIRECT (nanosleep, (const struct timespec *__requested_time,
+                                   struct timespec *__remaining),
+                       __nanosleep64);
+extern int __REDIRECT_NTH (clock_getres, (clockid_t __clock_id,
+                                          struct timespec *__res),
+                           __clock_getres64);
+extern int __REDIRECT_NTH (clock_gettime, (clockid_t __clock_id, struct
+                                           timespec *__tp), __clock_gettime64);
+extern int __REDIRECT_NTH (clock_settime, (clockid_t __clock_id, const struct
+                                           timespec *__tp), __clock_settime64);
+#  else
+#   define nanosleep __nanosleep64
+#   define clock_getres __clock_getres64
+#   define clock_gettime __clock_gettime64
+#   define clock_settime __clock_settime64
+#  endif
+# endif
+
+
+# ifdef __USE_XOPEN2K
+/* High-resolution sleep with the specified clock.
+
+   This function is a cancellation point and therefore not marked with
+   __THROW.  */
+#  ifndef __USE_TIME_BITS64
+extern int clock_nanosleep (clockid_t __clock_id, int __flags,
+			    const struct timespec *__req,
+			    struct timespec *__rem);
+#  else
+#   ifdef __REDIRECT
+extern int __REDIRECT (clock_nanosleep, (clockid_t __clock_id, int __flags,
+                                         const struct timespec *__req,
+                                         struct timespec *__rem),
+                       __clock_nanosleep_time64);
+#   else
+#    define clock_nanosleep __clock_nanosleep_time64
+#   endif
+#  endif
+
+/* Return clock ID for CPU-time clock.  */
+extern int clock_getcpuclockid (pid_t __pid, clockid_t *__clock_id) __THROW;
+# endif
+
+
+/* Create new per-process timer using CLOCK_ID.  */
+extern int timer_create (clockid_t __clock_id,
+			 struct sigevent *__restrict __evp,
+			 timer_t *__restrict __timerid) __THROW;
+
+/* Delete timer TIMERID.  */
+extern int timer_delete (timer_t __timerid) __THROW;
+
+/* Set timer TIMERID to VALUE, returning old value in OVALUE.  */
+# ifndef __USE_TIME_BITS64
+extern int timer_settime (timer_t __timerid, int __flags,
+			  const struct itimerspec *__restrict __value,
+			  struct itimerspec *__restrict __ovalue) __THROW;
+
+/* Get current value of timer TIMERID and store it in VALUE.  */
+extern int timer_gettime (timer_t __timerid, struct itimerspec *__value)
+     __THROW;
+# else
+#  ifdef __REDIRECT_NTH
+extern int __REDIRECT_NTH (timer_settime, (timer_t __timerid, int __flags,
+     const struct itimerspec *__restrict __value,
+     struct itimerspec *__restrict __ovalue),
+                          __timer_settime64);
+
+extern int __REDIRECT_NTH (timer_gettime, (timer_t __timerid,
+                                           struct itimerspec *__value),
+                           __timer_gettime64);
+#  else
+#   define timer_settime __timer_settime64
+#   define timer_gettime __timer_gettime64
+#  endif
+# endif
+
+/* Get expiration overrun for timer TIMERID.  */
+extern int timer_getoverrun (timer_t __timerid) __THROW;
+#endif
+
+
+#ifdef __USE_ISOC11
+# ifndef __USE_TIME_BITS64
+/* Set TS to calendar time based in time base BASE.  */
+extern int timespec_get (struct timespec *__ts, int __base)
+     __THROW __nonnull ((1));
+# else
+#  ifdef __REDIRECT_NTH
+extern int __REDIRECT_NTH (timespec_get, (struct timespec *__ts, int __base),
+                           __timespec_get64) __nonnull ((1));
+#  else
+#   define timespec_get __timespec_get64
+#  endif
+# endif
+#endif
+
+
+#if __GLIBC_USE (ISOC2X)
+# ifndef __USE_TIME_BITS64
+/* Set TS to resolution of time base BASE.  */
+extern int timespec_getres (struct timespec *__ts, int __base)
+     __THROW;
+# else
+#  ifdef __REDIRECT_NTH
+extern int __REDIRECT_NTH (timespec_getres, (struct timespec *__ts,
+                                             int __base),
+                           __timespec_getres64);
+#  else
+#   define timespec_getres __timespec_getres64
+#  endif
+# endif
+#endif
+
+
+#ifdef __USE_XOPEN_EXTENDED
+/* Set to one of the following values to indicate an error.
+     1  the DATEMSK environment variable is null or undefined,
+     2  the template file cannot be opened for reading,
+     3  failed to get file status information,
+     4  the template file is not a regular file,
+     5  an error is encountered while reading the template file,
+     6  memory allication failed (not enough memory available),
+     7  there is no line in the template that matches the input,
+     8  invalid input specification Example: February 31 or a time is
+	specified that can not be represented in a time_t (representing
+	the time in seconds since 00:00:00 UTC, January 1, 1970) */
+extern int getdate_err;
+
+/* Parse the given string as a date specification and return a value
+   representing the value.  The templates from the file identified by
+   the environment variable DATEMSK are used.  In case of an error
+   `getdate_err' is set.
+
+   This function is a possible cancellation point and therefore not
+   marked with __THROW.  */
+extern struct tm *getdate (const char *__string);
+#endif
+
+#ifdef __USE_GNU
+/* Since `getdate' is not reentrant because of the use of `getdate_err'
+   and the static buffer to return the result in, we provide a thread-safe
+   variant.  The functionality is the same.  The result is returned in
+   the buffer pointed to by RESBUFP and in case of an error the return
+   value is != 0 with the same values as given above for `getdate_err'.
+
+   This function is not part of POSIX and therefore no official
+   cancellation point.  But due to similarity with an POSIX interface
+   or due to the implementation it is a cancellation point and
+   therefore not marked with __THROW.  */
+extern int getdate_r (const char *__restrict __string,
+		      struct tm *__restrict __resbufp);
+#endif
+
+__END_DECLS
+
+#endif /* time.h.  */
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@uchar.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@uchar.h
new file mode 100644
index 0000000000000000000000000000000000000000..051cdcbeb5082cc7e27ed08398da1c685f6297e4
--- /dev/null
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@@ -0,0 +1,67 @@
+/* Copyright (C) 2011-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+/*
+ *      ISO C11 Standard: 7.28
+ *	Unicode utilities	<uchar.h>
+ */
+
+#ifndef _UCHAR_H
+#define _UCHAR_H	1
+
+#include <features.h>
+
+#define __need_size_t
+#include <stddef.h>
+
+#include <bits/types.h>
+#include <bits/types/mbstate_t.h>
+
+#ifndef __USE_ISOCXX11
+/* Define the 16-bit and 32-bit character types.  */
+typedef __uint_least16_t char16_t;
+typedef __uint_least32_t char32_t;
+#endif
+
+
+__BEGIN_DECLS
+
+/* Write char16_t representation of multibyte character pointed
+   to by S to PC16.  */
+extern size_t mbrtoc16 (char16_t *__restrict __pc16,
+			const char *__restrict __s, size_t __n,
+			mbstate_t *__restrict __p) __THROW;
+
+/* Write multibyte representation of char16_t C16 to S.  */
+extern size_t c16rtomb (char *__restrict __s, char16_t __c16,
+			mbstate_t *__restrict __ps) __THROW;
+
+
+
+/* Write char32_t representation of multibyte character pointed
+   to by S to PC32.  */
+extern size_t mbrtoc32 (char32_t *__restrict __pc32,
+			const char *__restrict __s, size_t __n,
+			mbstate_t *__restrict __p) __THROW;
+
+/* Write multibyte representation of char32_t C32 to S.  */
+extern size_t c32rtomb (char *__restrict __s, char32_t __c32,
+			mbstate_t *__restrict __ps) __THROW;
+
+__END_DECLS
+
+#endif	/* uchar.h */
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@unistd.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@unistd.h
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@unistd.h
@@ -0,0 +1,1222 @@
+/* Copyright (C) 1991-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+/*
+ *	POSIX Standard: 2.10 Symbolic Constants		<unistd.h>
+ */
+
+#ifndef	_UNISTD_H
+#define	_UNISTD_H	1
+
+#include <features.h>
+
+__BEGIN_DECLS
+
+/* These may be used to determine what facilities are present at compile time.
+   Their values can be obtained at run time from `sysconf'.  */
+
+#ifdef __USE_XOPEN2K8
+/* POSIX Standard approved as ISO/IEC 9945-1 as of September 2008.  */
+# define _POSIX_VERSION	200809L
+#elif defined __USE_XOPEN2K
+/* POSIX Standard approved as ISO/IEC 9945-1 as of December 2001.  */
+# define _POSIX_VERSION	200112L
+#elif defined __USE_POSIX199506
+/* POSIX Standard approved as ISO/IEC 9945-1 as of June 1995.  */
+# define _POSIX_VERSION	199506L
+#elif defined __USE_POSIX199309
+/* POSIX Standard approved as ISO/IEC 9945-1 as of September 1993.  */
+# define _POSIX_VERSION	199309L
+#else
+/* POSIX Standard approved as ISO/IEC 9945-1 as of September 1990.  */
+# define _POSIX_VERSION	199009L
+#endif
+
+/* These are not #ifdef __USE_POSIX2 because they are
+   in the theoretically application-owned namespace.  */
+
+#ifdef __USE_XOPEN2K8
+# define __POSIX2_THIS_VERSION	200809L
+/* The utilities on GNU systems also correspond to this version.  */
+#elif defined __USE_XOPEN2K
+/* The utilities on GNU systems also correspond to this version.  */
+# define __POSIX2_THIS_VERSION	200112L
+#elif defined __USE_POSIX199506
+/* The utilities on GNU systems also correspond to this version.  */
+# define __POSIX2_THIS_VERSION	199506L
+#else
+/* The utilities on GNU systems also correspond to this version.  */
+# define __POSIX2_THIS_VERSION	199209L
+#endif
+
+/* The utilities on GNU systems also correspond to this version.  */
+#define _POSIX2_VERSION	__POSIX2_THIS_VERSION
+
+/* This symbol was required until the 2001 edition of POSIX.  */
+#define	_POSIX2_C_VERSION	__POSIX2_THIS_VERSION
+
+/* If defined, the implementation supports the
+   C Language Bindings Option.  */
+#define	_POSIX2_C_BIND	__POSIX2_THIS_VERSION
+
+/* If defined, the implementation supports the
+   C Language Development Utilities Option.  */
+#define	_POSIX2_C_DEV	__POSIX2_THIS_VERSION
+
+/* If defined, the implementation supports the
+   Software Development Utilities Option.  */
+#define	_POSIX2_SW_DEV	__POSIX2_THIS_VERSION
+
+/* If defined, the implementation supports the
+   creation of locales with the localedef utility.  */
+#define _POSIX2_LOCALEDEF       __POSIX2_THIS_VERSION
+
+/* X/Open version number to which the library conforms.  It is selectable.  */
+#ifdef __USE_XOPEN2K8
+# define _XOPEN_VERSION	700
+#elif defined __USE_XOPEN2K
+# define _XOPEN_VERSION	600
+#elif defined __USE_UNIX98
+# define _XOPEN_VERSION	500
+#else
+# define _XOPEN_VERSION	4
+#endif
+
+/* Commands and utilities from XPG4 are available.  */
+#define _XOPEN_XCU_VERSION	4
+
+/* We are compatible with the old published standards as well.  */
+#define _XOPEN_XPG2	1
+#define _XOPEN_XPG3	1
+#define _XOPEN_XPG4	1
+
+/* The X/Open Unix extensions are available.  */
+#define _XOPEN_UNIX	1
+
+/* The enhanced internationalization capabilities according to XPG4.2
+   are present.  */
+#define	_XOPEN_ENH_I18N	1
+
+/* The legacy interfaces are also available.  */
+#define _XOPEN_LEGACY	1
+
+
+/* Get values of POSIX options:
+
+   If these symbols are defined, the corresponding features are
+   always available.  If not, they may be available sometimes.
+   The current values can be obtained with `sysconf'.
+
+   _POSIX_JOB_CONTROL		Job control is supported.
+   _POSIX_SAVED_IDS		Processes have a saved set-user-ID
+				and a saved set-group-ID.
+   _POSIX_REALTIME_SIGNALS	Real-time, queued signals are supported.
+   _POSIX_PRIORITY_SCHEDULING	Priority scheduling is supported.
+   _POSIX_TIMERS		POSIX.4 clocks and timers are supported.
+   _POSIX_ASYNCHRONOUS_IO	Asynchronous I/O is supported.
+   _POSIX_PRIORITIZED_IO	Prioritized asynchronous I/O is supported.
+   _POSIX_SYNCHRONIZED_IO	Synchronizing file data is supported.
+   _POSIX_FSYNC			The fsync function is present.
+   _POSIX_MAPPED_FILES		Mapping of files to memory is supported.
+   _POSIX_MEMLOCK		Locking of all memory is supported.
+   _POSIX_MEMLOCK_RANGE		Locking of ranges of memory is supported.
+   _POSIX_MEMORY_PROTECTION	Setting of memory protections is supported.
+   _POSIX_MESSAGE_PASSING	POSIX.4 message queues are supported.
+   _POSIX_SEMAPHORES		POSIX.4 counting semaphores are supported.
+   _POSIX_SHARED_MEMORY_OBJECTS	POSIX.4 shared memory objects are supported.
+   _POSIX_THREADS		POSIX.1c pthreads are supported.
+   _POSIX_THREAD_ATTR_STACKADDR	Thread stack address attribute option supported.
+   _POSIX_THREAD_ATTR_STACKSIZE	Thread stack size attribute option supported.
+   _POSIX_THREAD_SAFE_FUNCTIONS	Thread-safe functions are supported.
+   _POSIX_THREAD_PRIORITY_SCHEDULING
+				POSIX.1c thread execution scheduling supported.
+   _POSIX_THREAD_PRIO_INHERIT	Thread priority inheritance option supported.
+   _POSIX_THREAD_PRIO_PROTECT	Thread priority protection option supported.
+   _POSIX_THREAD_PROCESS_SHARED	Process-shared synchronization supported.
+   _POSIX_PII			Protocol-independent interfaces are supported.
+   _POSIX_PII_XTI		XTI protocol-indep. interfaces are supported.
+   _POSIX_PII_SOCKET		Socket protocol-indep. interfaces are supported.
+   _POSIX_PII_INTERNET		Internet family of protocols supported.
+   _POSIX_PII_INTERNET_STREAM	Connection-mode Internet protocol supported.
+   _POSIX_PII_INTERNET_DGRAM	Connectionless Internet protocol supported.
+   _POSIX_PII_OSI		ISO/OSI family of protocols supported.
+   _POSIX_PII_OSI_COTS		Connection-mode ISO/OSI service supported.
+   _POSIX_PII_OSI_CLTS		Connectionless ISO/OSI service supported.
+   _POSIX_POLL			Implementation supports `poll' function.
+   _POSIX_SELECT		Implementation supports `select' and `pselect'.
+
+   _XOPEN_REALTIME		X/Open realtime support is available.
+   _XOPEN_REALTIME_THREADS	X/Open realtime thread support is available.
+   _XOPEN_SHM			Shared memory interface according to XPG4.2.
+
+   _XBS5_ILP32_OFF32		Implementation provides environment with 32-bit
+				int, long, pointer, and off_t types.
+   _XBS5_ILP32_OFFBIG		Implementation provides environment with 32-bit
+				int, long, and pointer and off_t with at least
+				64 bits.
+   _XBS5_LP64_OFF64		Implementation provides environment with 32-bit
+				int, and 64-bit long, pointer, and off_t types.
+   _XBS5_LPBIG_OFFBIG		Implementation provides environment with at
+				least 32 bits int and long, pointer, and off_t
+				with at least 64 bits.
+
+   If any of these symbols is defined as -1, the corresponding option is not
+   true for any file.  If any is defined as other than -1, the corresponding
+   option is true for all files.  If a symbol is not defined at all, the value
+   for a specific file can be obtained from `pathconf' and `fpathconf'.
+
+   _POSIX_CHOWN_RESTRICTED	Only the super user can use `chown' to change
+				the owner of a file.  `chown' can only be used
+				to change the group ID of a file to a group of
+				which the calling process is a member.
+   _POSIX_NO_TRUNC		Pathname components longer than
+				NAME_MAX generate an error.
+   _POSIX_VDISABLE		If defined, if the value of an element of the
+				`c_cc' member of `struct termios' is
+				_POSIX_VDISABLE, no character will have the
+				effect associated with that element.
+   _POSIX_SYNC_IO		Synchronous I/O may be performed.
+   _POSIX_ASYNC_IO		Asynchronous I/O may be performed.
+   _POSIX_PRIO_IO		Prioritized Asynchronous I/O may be performed.
+
+   Support for the Large File Support interface is not generally available.
+   If it is available the following constants are defined to one.
+   _LFS64_LARGEFILE		Low-level I/O supports large files.
+   _LFS64_STDIO			Standard I/O supports large files.
+   */
+
+#include <bits/posix_opt.h>
+
+/* Get the environment definitions from Unix98.  */
+#if defined __USE_UNIX98 || defined __USE_XOPEN2K
+# include <bits/environments.h>
+#endif
+
+/* Standard file descriptors.  */
+#define	STDIN_FILENO	0	/* Standard input.  */
+#define	STDOUT_FILENO	1	/* Standard output.  */
+#define	STDERR_FILENO	2	/* Standard error output.  */
+
+
+/* All functions that are not declared anywhere else.  */
+
+#include <bits/types.h>
+
+#ifndef	__ssize_t_defined
+typedef __ssize_t ssize_t;
+# define __ssize_t_defined
+#endif
+
+#define	__need_size_t
+#define __need_NULL
+#include <stddef.h>
+
+#if defined __USE_XOPEN || defined __USE_XOPEN2K
+/* The Single Unix specification says that some more types are
+   available here.  */
+# ifndef __gid_t_defined
+typedef __gid_t gid_t;
+#  define __gid_t_defined
+# endif
+
+# ifndef __uid_t_defined
+typedef __uid_t uid_t;
+#  define __uid_t_defined
+# endif
+
+# ifndef __off_t_defined
+#  ifndef __USE_FILE_OFFSET64
+typedef __off_t off_t;
+#  else
+typedef __off64_t off_t;
+#  endif
+#  define __off_t_defined
+# endif
+# if defined __USE_LARGEFILE64 && !defined __off64_t_defined
+typedef __off64_t off64_t;
+#  define __off64_t_defined
+# endif
+
+# ifndef __useconds_t_defined
+typedef __useconds_t useconds_t;
+#  define __useconds_t_defined
+# endif
+
+# ifndef __pid_t_defined
+typedef __pid_t pid_t;
+#  define __pid_t_defined
+# endif
+#endif	/* X/Open */
+
+#if defined __USE_XOPEN_EXTENDED || defined __USE_XOPEN2K
+# ifndef __intptr_t_defined
+typedef __intptr_t intptr_t;
+#  define __intptr_t_defined
+# endif
+#endif
+
+#if defined __USE_MISC || defined __USE_XOPEN
+# ifndef __socklen_t_defined
+typedef __socklen_t socklen_t;
+#  define __socklen_t_defined
+# endif
+#endif
+
+/* Values for the second argument to access.
+   These may be OR'd together.  */
+#define	R_OK	4		/* Test for read permission.  */
+#define	W_OK	2		/* Test for write permission.  */
+#define	X_OK	1		/* Test for execute permission.  */
+#define	F_OK	0		/* Test for existence.  */
+
+/* Test for access to NAME using the real UID and real GID.  */
+extern int access (const char *__name, int __type) __THROW __nonnull ((1));
+
+#ifdef __USE_GNU
+/* Test for access to NAME using the effective UID and GID
+   (as normal file operations use).  */
+extern int euidaccess (const char *__name, int __type)
+     __THROW __nonnull ((1));
+
+/* An alias for `euidaccess', used by some other systems.  */
+extern int eaccess (const char *__name, int __type)
+     __THROW __nonnull ((1));
+
+/* Execute program relative to a directory file descriptor.  */
+extern int execveat (int __fd, const char *__path, char *const __argv[],
+                     char *const __envp[], int __flags)
+    __THROW __nonnull ((2, 3));
+#endif
+
+#ifdef __USE_ATFILE
+/* Test for access to FILE relative to the directory FD is open on.
+   If AT_EACCESS is set in FLAG, then use effective IDs like `eaccess',
+   otherwise use real IDs like `access'.  */
+extern int faccessat (int __fd, const char *__file, int __type, int __flag)
+     __THROW __nonnull ((2)) __wur;
+#endif /* Use GNU.  */
+
+
+/* Values for the WHENCE argument to lseek.  */
+#ifndef	_STDIO_H		/* <stdio.h> has the same definitions.  */
+# define SEEK_SET	0	/* Seek from beginning of file.  */
+# define SEEK_CUR	1	/* Seek from current position.  */
+# define SEEK_END	2	/* Seek from end of file.  */
+# ifdef __USE_GNU
+#  define SEEK_DATA	3	/* Seek to next data.  */
+#  define SEEK_HOLE	4	/* Seek to next hole.  */
+# endif
+#endif
+
+#if defined __USE_MISC && !defined L_SET
+/* Old BSD names for the same constants; just for compatibility.  */
+# define L_SET		SEEK_SET
+# define L_INCR		SEEK_CUR
+# define L_XTND		SEEK_END
+#endif
+
+
+/* Move FD's file position to OFFSET bytes from the
+   beginning of the file (if WHENCE is SEEK_SET),
+   the current position (if WHENCE is SEEK_CUR),
+   or the end of the file (if WHENCE is SEEK_END).
+   Return the new file position.  */
+#ifndef __USE_FILE_OFFSET64
+extern __off_t lseek (int __fd, __off_t __offset, int __whence) __THROW;
+#else
+# ifdef __REDIRECT_NTH
+extern __off64_t __REDIRECT_NTH (lseek,
+				 (int __fd, __off64_t __offset, int __whence),
+				 lseek64);
+# else
+#  define lseek lseek64
+# endif
+#endif
+#ifdef __USE_LARGEFILE64
+extern __off64_t lseek64 (int __fd, __off64_t __offset, int __whence)
+     __THROW;
+#endif
+
+/* Close the file descriptor FD.
+
+   This function is a cancellation point and therefore not marked with
+   __THROW.  */
+extern int close (int __fd);
+
+#ifdef __USE_MISC
+/* Close all open file descriptors greater than or equal to LOWFD.
+   Negative LOWFD is clamped to 0.  */
+extern void closefrom (int __lowfd) __THROW;
+#endif
+
+/* Read NBYTES into BUF from FD.  Return the
+   number read, -1 for errors or 0 for EOF.
+
+   This function is a cancellation point and therefore not marked with
+   __THROW.  */
+extern ssize_t read (int __fd, void *__buf, size_t __nbytes) __wur
+    __fortified_attr_access (__write_only__, 2, 3);
+
+/* Write N bytes of BUF to FD.  Return the number written, or -1.
+
+   This function is a cancellation point and therefore not marked with
+   __THROW.  */
+extern ssize_t write (int __fd, const void *__buf, size_t __n) __wur
+    __attr_access ((__read_only__, 2, 3));
+
+#if defined __USE_UNIX98 || defined __USE_XOPEN2K8
+# ifndef __USE_FILE_OFFSET64
+/* Read NBYTES into BUF from FD at the given position OFFSET without
+   changing the file pointer.  Return the number read, -1 for errors
+   or 0 for EOF.
+
+   This function is a cancellation point and therefore not marked with
+   __THROW.  */
+extern ssize_t pread (int __fd, void *__buf, size_t __nbytes,
+		      __off_t __offset) __wur
+    __fortified_attr_access (__write_only__, 2, 3);
+
+/* Write N bytes of BUF to FD at the given position OFFSET without
+   changing the file pointer.  Return the number written, or -1.
+
+   This function is a cancellation point and therefore not marked with
+   __THROW.  */
+extern ssize_t pwrite (int __fd, const void *__buf, size_t __n,
+		       __off_t __offset) __wur
+    __attr_access ((__read_only__, 2, 3));
+
+# else
+#  ifdef __REDIRECT
+extern ssize_t __REDIRECT (pread, (int __fd, void *__buf, size_t __nbytes,
+				   __off64_t __offset),
+			   pread64) __wur
+    __fortified_attr_access (__write_only__, 2, 3);
+extern ssize_t __REDIRECT (pwrite, (int __fd, const void *__buf,
+				    size_t __nbytes, __off64_t __offset),
+			   pwrite64) __wur
+    __attr_access ((__read_only__, 2, 3));
+#  else
+#   define pread pread64
+#   define pwrite pwrite64
+#  endif
+# endif
+
+# ifdef __USE_LARGEFILE64
+/* Read NBYTES into BUF from FD at the given position OFFSET without
+   changing the file pointer.  Return the number read, -1 for errors
+   or 0 for EOF.  */
+extern ssize_t pread64 (int __fd, void *__buf, size_t __nbytes,
+			__off64_t __offset) __wur
+    __fortified_attr_access (__write_only__, 2, 3);
+/* Write N bytes of BUF to FD at the given position OFFSET without
+   changing the file pointer.  Return the number written, or -1.  */
+extern ssize_t pwrite64 (int __fd, const void *__buf, size_t __n,
+			 __off64_t __offset) __wur
+    __attr_access ((__read_only__, 2, 3));
+# endif
+#endif
+
+/* Create a one-way communication channel (pipe).
+   If successful, two file descriptors are stored in PIPEDES;
+   bytes written on PIPEDES[1] can be read from PIPEDES[0].
+   Returns 0 if successful, -1 if not.  */
+extern int pipe (int __pipedes[2]) __THROW __wur;
+
+#ifdef __USE_GNU
+/* Same as pipe but apply flags passed in FLAGS to the new file
+   descriptors.  */
+extern int pipe2 (int __pipedes[2], int __flags) __THROW __wur;
+#endif
+
+/* Schedule an alarm.  In SECONDS seconds, the process will get a SIGALRM.
+   If SECONDS is zero, any currently scheduled alarm will be cancelled.
+   The function returns the number of seconds remaining until the last
+   alarm scheduled would have signaled, or zero if there wasn't one.
+   There is no return value to indicate an error, but you can set `errno'
+   to 0 and check its value after calling `alarm', and this might tell you.
+   The signal may come late due to processor scheduling.  */
+extern unsigned int alarm (unsigned int __seconds) __THROW;
+
+/* Make the process sleep for SECONDS seconds, or until a signal arrives
+   and is not ignored.  The function returns the number of seconds less
+   than SECONDS which it actually slept (thus zero if it slept the full time).
+   If a signal handler does a `longjmp' or modifies the handling of the
+   SIGALRM signal while inside `sleep' call, the handling of the SIGALRM
+   signal afterwards is undefined.  There is no return value to indicate
+   error, but if `sleep' returns SECONDS, it probably didn't work.
+
+   This function is a cancellation point and therefore not marked with
+   __THROW.  */
+extern unsigned int sleep (unsigned int __seconds);
+
+#if (defined __USE_XOPEN_EXTENDED && !defined __USE_XOPEN2K8) \
+    || defined __USE_MISC
+/* Set an alarm to go off (generating a SIGALRM signal) in VALUE
+   microseconds.  If INTERVAL is nonzero, when the alarm goes off, the
+   timer is reset to go off every INTERVAL microseconds thereafter.
+   Returns the number of microseconds remaining before the alarm.  */
+extern __useconds_t ualarm (__useconds_t __value, __useconds_t __interval)
+     __THROW;
+
+/* Sleep USECONDS microseconds, or until a signal arrives that is not blocked
+   or ignored.
+
+   This function is a cancellation point and therefore not marked with
+   __THROW.  */
+extern int usleep (__useconds_t __useconds);
+#endif
+
+
+/* Suspend the process until a signal arrives.
+   This always returns -1 and sets `errno' to EINTR.
+
+   This function is a cancellation point and therefore not marked with
+   __THROW.  */
+extern int pause (void);
+
+
+/* Change the owner and group of FILE.  */
+extern int chown (const char *__file, __uid_t __owner, __gid_t __group)
+     __THROW __nonnull ((1)) __wur;
+
+#if defined __USE_XOPEN_EXTENDED || defined __USE_XOPEN2K8
+/* Change the owner and group of the file that FD is open on.  */
+extern int fchown (int __fd, __uid_t __owner, __gid_t __group) __THROW __wur;
+
+
+/* Change owner and group of FILE, if it is a symbolic
+   link the ownership of the symbolic link is changed.  */
+extern int lchown (const char *__file, __uid_t __owner, __gid_t __group)
+     __THROW __nonnull ((1)) __wur;
+
+#endif /* Use X/Open Unix.  */
+
+#ifdef __USE_ATFILE
+/* Change the owner and group of FILE relative to the directory FD is open
+   on.  */
+extern int fchownat (int __fd, const char *__file, __uid_t __owner,
+		     __gid_t __group, int __flag)
+     __THROW __nonnull ((2)) __wur;
+#endif /* Use GNU.  */
+
+/* Change the process's working directory to PATH.  */
+extern int chdir (const char *__path) __THROW __nonnull ((1)) __wur;
+
+#if defined __USE_XOPEN_EXTENDED || defined __USE_XOPEN2K8
+/* Change the process's working directory to the one FD is open on.  */
+extern int fchdir (int __fd) __THROW __wur;
+#endif
+
+/* Get the pathname of the current working directory,
+   and put it in SIZE bytes of BUF.  Returns NULL if the
+   directory couldn't be determined or SIZE was too small.
+   If successful, returns BUF.  In GNU, if BUF is NULL,
+   an array is allocated with `malloc'; the array is SIZE
+   bytes long, unless SIZE == 0, in which case it is as
+   big as necessary.  */
+extern char *getcwd (char *__buf, size_t __size) __THROW __wur;
+
+#ifdef	__USE_GNU
+/* Return a malloc'd string containing the current directory name.
+   If the environment variable `PWD' is set, and its value is correct,
+   that value is used.  */
+extern char *get_current_dir_name (void) __THROW;
+#endif
+
+#if (defined __USE_XOPEN_EXTENDED && !defined __USE_XOPEN2K8) \
+    || defined __USE_MISC
+/* Put the absolute pathname of the current working directory in BUF.
+   If successful, return BUF.  If not, put an error message in
+   BUF and return NULL.  BUF should be at least PATH_MAX bytes long.  */
+extern char *getwd (char *__buf)
+     __THROW __nonnull ((1)) __attribute_deprecated__ __wur
+    __attr_access ((__write_only__, 1));
+#endif
+
+
+/* Duplicate FD, returning a new file descriptor on the same file.  */
+extern int dup (int __fd) __THROW __wur;
+
+/* Duplicate FD to FD2, closing FD2 and making it open on the same file.  */
+extern int dup2 (int __fd, int __fd2) __THROW;
+
+#ifdef __USE_GNU
+/* Duplicate FD to FD2, closing FD2 and making it open on the same
+   file while setting flags according to FLAGS.  */
+extern int dup3 (int __fd, int __fd2, int __flags) __THROW;
+#endif
+
+/* NULL-terminated array of "NAME=VALUE" environment variables.  */
+extern char **__environ;
+#ifdef __USE_GNU
+extern char **environ;
+#endif
+
+
+/* Replace the current process, executing PATH with arguments ARGV and
+   environment ENVP.  ARGV and ENVP are terminated by NULL pointers.  */
+extern int execve (const char *__path, char *const __argv[],
+		   char *const __envp[]) __THROW __nonnull ((1, 2));
+
+#ifdef __USE_XOPEN2K8
+/* Execute the file FD refers to, overlaying the running program image.
+   ARGV and ENVP are passed to the new program, as for `execve'.  */
+extern int fexecve (int __fd, char *const __argv[], char *const __envp[])
+     __THROW __nonnull ((2));
+#endif
+
+
+/* Execute PATH with arguments ARGV and environment from `environ'.  */
+extern int execv (const char *__path, char *const __argv[])
+     __THROW __nonnull ((1, 2));
+
+/* Execute PATH with all arguments after PATH until a NULL pointer,
+   and the argument after that for environment.  */
+extern int execle (const char *__path, const char *__arg, ...)
+     __THROW __nonnull ((1, 2));
+
+/* Execute PATH with all arguments after PATH until
+   a NULL pointer and environment from `environ'.  */
+extern int execl (const char *__path, const char *__arg, ...)
+     __THROW __nonnull ((1, 2));
+
+/* Execute FILE, searching in the `PATH' environment variable if it contains
+   no slashes, with arguments ARGV and environment from `environ'.  */
+extern int execvp (const char *__file, char *const __argv[])
+     __THROW __nonnull ((1, 2));
+
+/* Execute FILE, searching in the `PATH' environment variable if
+   it contains no slashes, with all arguments after FILE until a
+   NULL pointer and environment from `environ'.  */
+extern int execlp (const char *__file, const char *__arg, ...)
+     __THROW __nonnull ((1, 2));
+
+#ifdef __USE_GNU
+/* Execute FILE, searching in the `PATH' environment variable if it contains
+   no slashes, with arguments ARGV and environment from `environ'.  */
+extern int execvpe (const char *__file, char *const __argv[],
+		    char *const __envp[])
+     __THROW __nonnull ((1, 2));
+#endif
+
+
+#if defined __USE_MISC || defined __USE_XOPEN
+/* Add INC to priority of the current process.  */
+extern int nice (int __inc) __THROW __wur;
+#endif
+
+
+/* Terminate program execution with the low-order 8 bits of STATUS.  */
+extern void _exit (int __status) __attribute__ ((__noreturn__));
+
+
+/* Get the `_PC_*' symbols for the NAME argument to `pathconf' and `fpathconf';
+   the `_SC_*' symbols for the NAME argument to `sysconf';
+   and the `_CS_*' symbols for the NAME argument to `confstr'.  */
+#include <bits/confname.h>
+
+/* Get file-specific configuration information about PATH.  */
+extern long int pathconf (const char *__path, int __name)
+     __THROW __nonnull ((1));
+
+/* Get file-specific configuration about descriptor FD.  */
+extern long int fpathconf (int __fd, int __name) __THROW;
+
+/* Get the value of the system variable NAME.  */
+extern long int sysconf (int __name) __THROW;
+
+#ifdef	__USE_POSIX2
+/* Get the value of the string-valued system variable NAME.  */
+extern size_t confstr (int __name, char *__buf, size_t __len) __THROW
+    __fortified_attr_access (__write_only__, 2, 3);
+#endif
+
+
+/* Get the process ID of the calling process.  */
+extern __pid_t getpid (void) __THROW;
+
+/* Get the process ID of the calling process's parent.  */
+extern __pid_t getppid (void) __THROW;
+
+/* Get the process group ID of the calling process.  */
+extern __pid_t getpgrp (void) __THROW;
+
+/* Get the process group ID of process PID.  */
+extern __pid_t __getpgid (__pid_t __pid) __THROW;
+#if defined __USE_XOPEN_EXTENDED || defined __USE_XOPEN2K8
+extern __pid_t getpgid (__pid_t __pid) __THROW;
+#endif
+
+
+/* Set the process group ID of the process matching PID to PGID.
+   If PID is zero, the current process's process group ID is set.
+   If PGID is zero, the process ID of the process is used.  */
+extern int setpgid (__pid_t __pid, __pid_t __pgid) __THROW;
+
+#if defined __USE_MISC || defined __USE_XOPEN_EXTENDED
+/* Both System V and BSD have `setpgrp' functions, but with different
+   calling conventions.  The BSD function is the same as POSIX.1 `setpgid'
+   (above).  The System V function takes no arguments and puts the calling
+   process in its on group like `setpgid (0, 0)'.
+
+   New programs should always use `setpgid' instead.
+
+   GNU provides the POSIX.1 function.  */
+
+/* Set the process group ID of the calling process to its own PID.
+   This is exactly the same as `setpgid (0, 0)'.  */
+extern int setpgrp (void) __THROW;
+
+#endif	/* Use misc or X/Open.  */
+
+/* Create a new session with the calling process as its leader.
+   The process group IDs of the session and the calling process
+   are set to the process ID of the calling process, which is returned.  */
+extern __pid_t setsid (void) __THROW;
+
+#if defined __USE_XOPEN_EXTENDED || defined __USE_XOPEN2K8
+/* Return the session ID of the given process.  */
+extern __pid_t getsid (__pid_t __pid) __THROW;
+#endif
+
+/* Get the real user ID of the calling process.  */
+extern __uid_t getuid (void) __THROW;
+
+/* Get the effective user ID of the calling process.  */
+extern __uid_t geteuid (void) __THROW;
+
+/* Get the real group ID of the calling process.  */
+extern __gid_t getgid (void) __THROW;
+
+/* Get the effective group ID of the calling process.  */
+extern __gid_t getegid (void) __THROW;
+
+/* If SIZE is zero, return the number of supplementary groups
+   the calling process is in.  Otherwise, fill in the group IDs
+   of its supplementary groups in LIST and return the number written.  */
+extern int getgroups (int __size, __gid_t __list[]) __THROW __wur
+    __fortified_attr_access (__write_only__, 2, 1);
+#ifdef	__USE_GNU
+/* Return nonzero iff the calling process is in group GID.  */
+extern int group_member (__gid_t __gid) __THROW;
+#endif
+
+/* Set the user ID of the calling process to UID.
+   If the calling process is the super-user, set the real
+   and effective user IDs, and the saved set-user-ID to UID;
+   if not, the effective user ID is set to UID.  */
+extern int setuid (__uid_t __uid) __THROW __wur;
+
+#if defined __USE_MISC || defined __USE_XOPEN_EXTENDED
+/* Set the real user ID of the calling process to RUID,
+   and the effective user ID of the calling process to EUID.  */
+extern int setreuid (__uid_t __ruid, __uid_t __euid) __THROW __wur;
+#endif
+
+#ifdef __USE_XOPEN2K
+/* Set the effective user ID of the calling process to UID.  */
+extern int seteuid (__uid_t __uid) __THROW __wur;
+#endif /* Use POSIX.1-2001.  */
+
+/* Set the group ID of the calling process to GID.
+   If the calling process is the super-user, set the real
+   and effective group IDs, and the saved set-group-ID to GID;
+   if not, the effective group ID is set to GID.  */
+extern int setgid (__gid_t __gid) __THROW __wur;
+
+#if defined __USE_MISC || defined __USE_XOPEN_EXTENDED
+/* Set the real group ID of the calling process to RGID,
+   and the effective group ID of the calling process to EGID.  */
+extern int setregid (__gid_t __rgid, __gid_t __egid) __THROW __wur;
+#endif
+
+#ifdef __USE_XOPEN2K
+/* Set the effective group ID of the calling process to GID.  */
+extern int setegid (__gid_t __gid) __THROW __wur;
+#endif /* Use POSIX.1-2001.  */
+
+#ifdef __USE_GNU
+/* Fetch the real user ID, effective user ID, and saved-set user ID,
+   of the calling process.  */
+extern int getresuid (__uid_t *__ruid, __uid_t *__euid, __uid_t *__suid)
+     __THROW;
+
+/* Fetch the real group ID, effective group ID, and saved-set group ID,
+   of the calling process.  */
+extern int getresgid (__gid_t *__rgid, __gid_t *__egid, __gid_t *__sgid)
+     __THROW;
+
+/* Set the real user ID, effective user ID, and saved-set user ID,
+   of the calling process to RUID, EUID, and SUID, respectively.  */
+extern int setresuid (__uid_t __ruid, __uid_t __euid, __uid_t __suid)
+     __THROW __wur;
+
+/* Set the real group ID, effective group ID, and saved-set group ID,
+   of the calling process to RGID, EGID, and SGID, respectively.  */
+extern int setresgid (__gid_t __rgid, __gid_t __egid, __gid_t __sgid)
+     __THROW __wur;
+#endif
+
+
+/* Clone the calling process, creating an exact copy.
+   Return -1 for errors, 0 to the new process,
+   and the process ID of the new process to the old process.  */
+extern __pid_t fork (void) __THROWNL;
+
+#if (defined __USE_XOPEN_EXTENDED && !defined __USE_XOPEN2K8) \
+    || defined __USE_MISC
+/* Clone the calling process, but without copying the whole address space.
+   The calling process is suspended until the new process exits or is
+   replaced by a call to `execve'.  Return -1 for errors, 0 to the new process,
+   and the process ID of the new process to the old process.  */
+extern __pid_t vfork (void) __THROW;
+#endif /* Use misc or XPG < 7. */
+
+#ifdef __USE_GNU
+/* This is similar to fork, however it does not run the atfork handlers
+   neither reinitialize any internal locks in multithread case.
+   Different than fork, _Fork is async-signal-safe.  */
+extern __pid_t _Fork (void) __THROW;
+#endif
+
+
+/* Return the pathname of the terminal FD is open on, or NULL on errors.
+   The returned storage is good only until the next call to this function.  */
+extern char *ttyname (int __fd) __THROW;
+
+/* Store at most BUFLEN characters of the pathname of the terminal FD is
+   open on in BUF.  Return 0 on success, otherwise an error number.  */
+extern int ttyname_r (int __fd, char *__buf, size_t __buflen)
+     __THROW __nonnull ((2)) __wur
+     __fortified_attr_access (__write_only__, 2, 3);
+
+/* Return 1 if FD is a valid descriptor associated
+   with a terminal, zero if not.  */
+extern int isatty (int __fd) __THROW;
+
+#ifdef __USE_MISC
+/* Return the index into the active-logins file (utmp) for
+   the controlling terminal.  */
+extern int ttyslot (void) __THROW;
+#endif
+
+
+/* Make a link to FROM named TO.  */
+extern int link (const char *__from, const char *__to)
+     __THROW __nonnull ((1, 2)) __wur;
+
+#ifdef __USE_ATFILE
+/* Like link but relative paths in TO and FROM are interpreted relative
+   to FROMFD and TOFD respectively.  */
+extern int linkat (int __fromfd, const char *__from, int __tofd,
+		   const char *__to, int __flags)
+     __THROW __nonnull ((2, 4)) __wur;
+#endif
+
+#if defined __USE_XOPEN_EXTENDED || defined __USE_XOPEN2K
+/* Make a symbolic link to FROM named TO.  */
+extern int symlink (const char *__from, const char *__to)
+     __THROW __nonnull ((1, 2)) __wur;
+
+/* Read the contents of the symbolic link PATH into no more than
+   LEN bytes of BUF.  The contents are not null-terminated.
+   Returns the number of characters read, or -1 for errors.  */
+extern ssize_t readlink (const char *__restrict __path,
+			 char *__restrict __buf, size_t __len)
+     __THROW __nonnull ((1, 2)) __wur
+     __fortified_attr_access (__write_only__, 2, 3);
+
+#endif /* Use POSIX.1-2001.  */
+
+#ifdef __USE_ATFILE
+/* Like symlink but a relative path in TO is interpreted relative to TOFD.  */
+extern int symlinkat (const char *__from, int __tofd,
+		      const char *__to) __THROW __nonnull ((1, 3)) __wur;
+
+/* Like readlink but a relative PATH is interpreted relative to FD.  */
+extern ssize_t readlinkat (int __fd, const char *__restrict __path,
+			   char *__restrict __buf, size_t __len)
+     __THROW __nonnull ((2, 3)) __wur
+     __fortified_attr_access (__write_only__, 3, 4);
+#endif
+
+/* Remove the link NAME.  */
+extern int unlink (const char *__name) __THROW __nonnull ((1));
+
+#ifdef __USE_ATFILE
+/* Remove the link NAME relative to FD.  */
+extern int unlinkat (int __fd, const char *__name, int __flag)
+     __THROW __nonnull ((2));
+#endif
+
+/* Remove the directory PATH.  */
+extern int rmdir (const char *__path) __THROW __nonnull ((1));
+
+
+/* Return the foreground process group ID of FD.  */
+extern __pid_t tcgetpgrp (int __fd) __THROW;
+
+/* Set the foreground process group ID of FD set PGRP_ID.  */
+extern int tcsetpgrp (int __fd, __pid_t __pgrp_id) __THROW;
+
+
+/* Return the login name of the user.
+
+   This function is a possible cancellation point and therefore not
+   marked with __THROW.  */
+extern char *getlogin (void);
+#ifdef __USE_POSIX199506
+/* Return at most NAME_LEN characters of the login name of the user in NAME.
+   If it cannot be determined or some other error occurred, return the error
+   code.  Otherwise return 0.
+
+   This function is a possible cancellation point and therefore not
+   marked with __THROW.  */
+extern int getlogin_r (char *__name, size_t __name_len) __nonnull ((1))
+    __fortified_attr_access (__write_only__, 1, 2);
+#endif
+
+#ifdef	__USE_MISC
+/* Set the login name returned by `getlogin'.  */
+extern int setlogin (const char *__name) __THROW __nonnull ((1));
+#endif
+
+
+#ifdef	__USE_POSIX2
+/* Get definitions and prototypes for functions to process the
+   arguments in ARGV (ARGC of them, minus the program name) for
+   options given in OPTS.  */
+# include <bits/getopt_posix.h>
+#endif
+
+
+#if defined __USE_XOPEN_EXTENDED || defined __USE_XOPEN2K
+/* Put the name of the current host in no more than LEN bytes of NAME.
+   The result is null-terminated if LEN is large enough for the full
+   name and the terminator.  */
+extern int gethostname (char *__name, size_t __len) __THROW __nonnull ((1))
+    __fortified_attr_access (__write_only__, 1, 2);
+#endif
+
+
+#if defined __USE_MISC
+/* Set the name of the current host to NAME, which is LEN bytes long.
+   This call is restricted to the super-user.  */
+extern int sethostname (const char *__name, size_t __len)
+     __THROW __nonnull ((1)) __wur __attr_access ((__read_only__, 1, 2));
+
+/* Set the current machine's Internet number to ID.
+   This call is restricted to the super-user.  */
+extern int sethostid (long int __id) __THROW __wur;
+
+
+/* Get and set the NIS (aka YP) domain name, if any.
+   Called just like `gethostname' and `sethostname'.
+   The NIS domain name is usually the empty string when not using NIS.  */
+extern int getdomainname (char *__name, size_t __len)
+     __THROW __nonnull ((1)) __wur
+     __fortified_attr_access (__write_only__, 1, 2);
+extern int setdomainname (const char *__name, size_t __len)
+     __THROW __nonnull ((1)) __wur __attr_access ((__read_only__, 1, 2));
+
+/* Revoke access permissions to all processes currently communicating
+   with the control terminal, and then send a SIGHUP signal to the process
+   group of the control terminal.  */
+extern int vhangup (void) __THROW;
+
+/* Revoke the access of all descriptors currently open on FILE.  */
+extern int revoke (const char *__file) __THROW __nonnull ((1)) __wur;
+
+
+/* Enable statistical profiling, writing samples of the PC into at most
+   SIZE bytes of SAMPLE_BUFFER; every processor clock tick while profiling
+   is enabled, the system examines the user PC and increments
+   SAMPLE_BUFFER[((PC - OFFSET) / 2) * SCALE / 65536].  If SCALE is zero,
+   disable profiling.  Returns zero on success, -1 on error.  */
+extern int profil (unsigned short int *__sample_buffer, size_t __size,
+		   size_t __offset, unsigned int __scale)
+     __THROW __nonnull ((1));
+
+
+/* Turn accounting on if NAME is an existing file.  The system will then write
+   a record for each process as it terminates, to this file.  If NAME is NULL,
+   turn accounting off.  This call is restricted to the super-user.  */
+extern int acct (const char *__name) __THROW;
+
+
+/* Successive calls return the shells listed in `/etc/shells'.  */
+extern char *getusershell (void) __THROW;
+extern void endusershell (void) __THROW; /* Discard cached info.  */
+extern void setusershell (void) __THROW; /* Rewind and re-read the file.  */
+
+
+/* Put the program in the background, and dissociate from the controlling
+   terminal.  If NOCHDIR is zero, do `chdir ("/")'.  If NOCLOSE is zero,
+   redirects stdin, stdout, and stderr to /dev/null.  */
+extern int daemon (int __nochdir, int __noclose) __THROW __wur;
+#endif /* Use misc.  */
+
+
+#if defined __USE_MISC || (defined __USE_XOPEN && !defined __USE_XOPEN2K)
+/* Make PATH be the root directory (the starting point for absolute paths).
+   This call is restricted to the super-user.  */
+extern int chroot (const char *__path) __THROW __nonnull ((1)) __wur;
+
+/* Prompt with PROMPT and read a string from the terminal without echoing.
+   Uses /dev/tty if possible; otherwise stderr and stdin.  */
+extern char *getpass (const char *__prompt) __nonnull ((1));
+#endif /* Use misc || X/Open.  */
+
+
+/* Make all changes done to FD actually appear on disk.
+
+   This function is a cancellation point and therefore not marked with
+   __THROW.  */
+extern int fsync (int __fd);
+
+
+#ifdef __USE_GNU
+/* Make all changes done to all files on the file system associated
+   with FD actually appear on disk.  */
+extern int syncfs (int __fd) __THROW;
+#endif
+
+
+#if defined __USE_MISC || defined __USE_XOPEN_EXTENDED
+
+/* Return identifier for the current host.  */
+extern long int gethostid (void);
+
+/* Make all changes done to all files actually appear on disk.  */
+extern void sync (void) __THROW;
+
+
+# if defined __USE_MISC || !defined __USE_XOPEN2K
+/* Return the number of bytes in a page.  This is the system's page size,
+   which is not necessarily the same as the hardware page size.  */
+extern int getpagesize (void)  __THROW __attribute__ ((__const__));
+
+
+/* Return the maximum number of file descriptors
+   the current process could possibly have.  */
+extern int getdtablesize (void) __THROW;
+# endif
+
+#endif /* Use misc || X/Open Unix.  */
+
+
+#if defined __USE_XOPEN_EXTENDED || defined __USE_XOPEN2K8
+
+/* Truncate FILE to LENGTH bytes.  */
+# ifndef __USE_FILE_OFFSET64
+extern int truncate (const char *__file, __off_t __length)
+     __THROW __nonnull ((1)) __wur;
+# else
+#  ifdef __REDIRECT_NTH
+extern int __REDIRECT_NTH (truncate,
+			   (const char *__file, __off64_t __length),
+			   truncate64) __nonnull ((1)) __wur;
+#  else
+#   define truncate truncate64
+#  endif
+# endif
+# ifdef __USE_LARGEFILE64
+extern int truncate64 (const char *__file, __off64_t __length)
+     __THROW __nonnull ((1)) __wur;
+# endif
+
+#endif /* Use X/Open Unix || POSIX 2008.  */
+
+#if defined __USE_POSIX199309 \
+    || defined __USE_XOPEN_EXTENDED || defined __USE_XOPEN2K
+
+/* Truncate the file FD is open on to LENGTH bytes.  */
+# ifndef __USE_FILE_OFFSET64
+extern int ftruncate (int __fd, __off_t __length) __THROW __wur;
+# else
+#  ifdef __REDIRECT_NTH
+extern int __REDIRECT_NTH (ftruncate, (int __fd, __off64_t __length),
+			   ftruncate64) __wur;
+#  else
+#   define ftruncate ftruncate64
+#  endif
+# endif
+# ifdef __USE_LARGEFILE64
+extern int ftruncate64 (int __fd, __off64_t __length) __THROW __wur;
+# endif
+
+#endif /* Use POSIX.1b || X/Open Unix || XPG6.  */
+
+
+#if (defined __USE_XOPEN_EXTENDED && !defined __USE_XOPEN2K) \
+    || defined __USE_MISC
+
+/* Set the end of accessible data space (aka "the break") to ADDR.
+   Returns zero on success and -1 for errors (with errno set).  */
+extern int brk (void *__addr) __THROW __wur;
+
+/* Increase or decrease the end of accessible data space by DELTA bytes.
+   If successful, returns the address the previous end of data space
+   (i.e. the beginning of the new space, if DELTA > 0);
+   returns (void *) -1 for errors (with errno set).  */
+extern void *sbrk (intptr_t __delta) __THROW;
+#endif
+
+
+#ifdef __USE_MISC
+/* Invoke `system call' number SYSNO, passing it the remaining arguments.
+   This is completely system-dependent, and not often useful.
+
+   In Unix, `syscall' sets `errno' for all errors and most calls return -1
+   for errors; in many systems you cannot pass arguments or get return
+   values for all system calls (`pipe', `fork', and `getppid' typically
+   among them).
+
+   In Mach, all system calls take normal arguments and always return an
+   error code (zero for success).  */
+extern long int syscall (long int __sysno, ...) __THROW;
+
+#endif	/* Use misc.  */
+
+
+#if (defined __USE_MISC || defined __USE_XOPEN_EXTENDED) && !defined F_LOCK
+/* NOTE: These declarations also appear in <fcntl.h>; be sure to keep both
+   files consistent.  Some systems have them there and some here, and some
+   software depends on the macros being defined without including both.  */
+
+/* `lockf' is a simpler interface to the locking facilities of `fcntl'.
+   LEN is always relative to the current file position.
+   The CMD argument is one of the following.
+
+   This function is a cancellation point and therefore not marked with
+   __THROW.  */
+
+# define F_ULOCK 0	/* Unlock a previously locked region.  */
+# define F_LOCK  1	/* Lock a region for exclusive use.  */
+# define F_TLOCK 2	/* Test and lock a region for exclusive use.  */
+# define F_TEST  3	/* Test a region for other processes locks.  */
+
+# ifndef __USE_FILE_OFFSET64
+extern int lockf (int __fd, int __cmd, __off_t __len) __wur;
+# else
+#  ifdef __REDIRECT
+extern int __REDIRECT (lockf, (int __fd, int __cmd, __off64_t __len),
+		       lockf64) __wur;
+#  else
+#   define lockf lockf64
+#  endif
+# endif
+# ifdef __USE_LARGEFILE64
+extern int lockf64 (int __fd, int __cmd, __off64_t __len) __wur;
+# endif
+#endif /* Use misc and F_LOCK not already defined.  */
+
+
+#ifdef __USE_GNU
+
+/* Evaluate EXPRESSION, and repeat as long as it returns -1 with `errno'
+   set to EINTR.  */
+
+# define TEMP_FAILURE_RETRY(expression) \
+  (__extension__							      \
+    ({ long int __result;						      \
+       do __result = (long int) (expression);				      \
+       while (__result == -1L && errno == EINTR);			      \
+       __result; }))
+
+/* Copy LENGTH bytes from INFD to OUTFD.  */
+ssize_t copy_file_range (int __infd, __off64_t *__pinoff,
+			 int __outfd, __off64_t *__poutoff,
+			 size_t __length, unsigned int __flags);
+#endif /* __USE_GNU */
+
+#if defined __USE_POSIX199309 || defined __USE_UNIX98
+/* Synchronize at least the data part of a file with the underlying
+   media.  */
+extern int fdatasync (int __fildes);
+#endif /* Use POSIX199309 */
+
+#ifdef __USE_MISC
+/* One-way hash PHRASE, returning a string suitable for storage in the
+   user database.  SALT selects the one-way function to use, and
+   ensures that no two users' hashes are the same, even if they use
+   the same passphrase.  The return value points to static storage
+   which will be overwritten by the next call to crypt.  */
+extern char *crypt (const char *__key, const char *__salt)
+     __THROW __nonnull ((1, 2));
+#endif
+
+#ifdef	__USE_XOPEN
+/* Swab pairs bytes in the first N bytes of the area pointed to by
+   FROM and copy the result to TO.  The value of TO must not be in the
+   range [FROM - N + 1, FROM - 1].  If N is odd the first byte in FROM
+   is without partner.  */
+extern void swab (const void *__restrict __from, void *__restrict __to,
+		  ssize_t __n) __THROW __nonnull ((1, 2))
+    __attr_access ((__read_only__, 1, 3))
+    __attr_access ((__write_only__, 2, 3));
+#endif
+
+
+/* Prior to Issue 6, the Single Unix Specification required these
+   prototypes to appear in this header.  They are also found in
+   <stdio.h>.  */
+#if defined __USE_XOPEN && !defined __USE_XOPEN2K
+/* Return the name of the controlling terminal.  */
+extern char *ctermid (char *__s) __THROW;
+
+/* Return the name of the current user.  */
+extern char *cuserid (char *__s);
+#endif
+
+
+/* Unix98 requires this function to be declared here.  In other
+   standards it is in <pthread.h>.  */
+#if defined __USE_UNIX98 && !defined __USE_XOPEN2K
+extern int pthread_atfork (void (*__prepare) (void),
+			   void (*__parent) (void),
+			   void (*__child) (void)) __THROW;
+#endif
+
+#ifdef __USE_MISC
+/* Write LENGTH bytes of randomness starting at BUFFER.  Return 0 on
+   success or -1 on error.  */
+int getentropy (void *__buffer, size_t __length) __wur
+    __attr_access ((__write_only__, 1, 2));
+#endif
+
+#ifdef __USE_GNU
+/* Close all file descriptors in the range FD up to MAX_FD.  The flag FLAGS
+   are define by the CLOSE_RANGE prefix.  This function behaves like close
+   on the range and gaps where the file descriptor is invalid or errors
+   encountered while closing file descriptors are ignored.   Returns 0 on
+   successor or -1 for failure (and sets errno accordingly).  */
+extern int close_range (unsigned int __fd, unsigned int __max_fd,
+			int __flags) __THROW;
+#endif
+
+/* Define some macros helping to catch buffer overflows.  */
+#if __USE_FORTIFY_LEVEL > 0 && defined __fortify_function
+# include <bits/unistd.h>
+#endif
+
+/* System-specific extensions.  */
+#include <bits/unistd_ext.h>
+
+__END_DECLS
+
+#endif /* unistd.h  */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@unistd.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@unistd.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@wchar.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@wchar.h
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@@ -0,0 +1,884 @@
+/* Copyright (C) 1995-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+/*
+ *      ISO C99 Standard: 7.24
+ *	Extended multibyte and wide character utilities	<wchar.h>
+ */
+
+#ifndef _WCHAR_H
+#define _WCHAR_H 1
+
+#define __GLIBC_INTERNAL_STARTING_HEADER_IMPLEMENTATION
+#include <bits/libc-header-start.h>
+
+/* Gather machine dependent type support.  */
+#include <bits/floatn.h>
+
+#define __need_size_t
+#define __need_wchar_t
+#define __need_NULL
+#include <stddef.h>
+
+#define __need___va_list
+#include <stdarg.h>
+
+#include <bits/wchar.h>
+#include <bits/types/wint_t.h>
+#include <bits/types/mbstate_t.h>
+#include <bits/types/__FILE.h>
+
+#if defined __USE_UNIX98 || defined __USE_XOPEN2K
+# include <bits/types/FILE.h>
+#endif
+#ifdef __USE_XOPEN2K8
+# include <bits/types/locale_t.h>
+#endif
+
+/* Tell the caller that we provide correct C++ prototypes.  */
+#if defined __cplusplus && __GNUC_PREREQ (4, 4)
+# define __CORRECT_ISO_CPP_WCHAR_H_PROTO
+#endif
+
+#ifndef WCHAR_MIN
+/* These constants might also be defined in <inttypes.h>.  */
+# define WCHAR_MIN __WCHAR_MIN
+# define WCHAR_MAX __WCHAR_MAX
+#endif
+
+#ifndef WEOF
+# define WEOF (0xffffffffu)
+#endif
+
+/* All versions of XPG prior to the publication of ISO C99 required
+   the bulk of <wctype.h>'s declarations to appear in this header
+   (because <wctype.h> did not exist prior to C99).  In POSIX.1-2001
+   those declarations were marked as XSI extensions; in -2008 they
+   were additionally marked as obsolescent.  _GNU_SOURCE mode
+   anticipates the removal of these declarations in the next revision
+   of POSIX.  */
+#if (defined __USE_XOPEN && !defined __USE_GNU \
+     && !(defined __USE_XOPEN2K && !defined __USE_XOPEN2KXSI))
+# include <bits/wctype-wchar.h>
+#endif
+
+__BEGIN_DECLS
+
+/* This incomplete type is defined in <time.h> but needed here because
+   of `wcsftime'.  */
+struct tm;
+
+
+/* Copy SRC to DEST.  */
+extern wchar_t *wcscpy (wchar_t *__restrict __dest,
+			const wchar_t *__restrict __src)
+     __THROW __nonnull ((1, 2));
+
+/* Copy no more than N wide-characters of SRC to DEST.  */
+extern wchar_t *wcsncpy (wchar_t *__restrict __dest,
+			 const wchar_t *__restrict __src, size_t __n)
+     __THROW __nonnull ((1, 2));
+
+/* Append SRC onto DEST.  */
+extern wchar_t *wcscat (wchar_t *__restrict __dest,
+			const wchar_t *__restrict __src)
+     __THROW __nonnull ((1, 2));
+/* Append no more than N wide-characters of SRC onto DEST.  */
+extern wchar_t *wcsncat (wchar_t *__restrict __dest,
+			 const wchar_t *__restrict __src, size_t __n)
+     __THROW __nonnull ((1, 2));
+
+/* Compare S1 and S2.  */
+extern int wcscmp (const wchar_t *__s1, const wchar_t *__s2)
+     __THROW __attribute_pure__ __nonnull ((1, 2));
+/* Compare N wide-characters of S1 and S2.  */
+extern int wcsncmp (const wchar_t *__s1, const wchar_t *__s2, size_t __n)
+     __THROW __attribute_pure__ __nonnull ((1, 2));
+
+#ifdef __USE_XOPEN2K8
+/* Compare S1 and S2, ignoring case.  */
+extern int wcscasecmp (const wchar_t *__s1, const wchar_t *__s2) __THROW;
+
+/* Compare no more than N chars of S1 and S2, ignoring case.  */
+extern int wcsncasecmp (const wchar_t *__s1, const wchar_t *__s2,
+			size_t __n) __THROW;
+
+/* Similar to the two functions above but take the information from
+   the provided locale and not the global locale.  */
+extern int wcscasecmp_l (const wchar_t *__s1, const wchar_t *__s2,
+			 locale_t __loc) __THROW;
+
+extern int wcsncasecmp_l (const wchar_t *__s1, const wchar_t *__s2,
+			  size_t __n, locale_t __loc) __THROW;
+#endif
+
+/* Compare S1 and S2, both interpreted as appropriate to the
+   LC_COLLATE category of the current locale.  */
+extern int wcscoll (const wchar_t *__s1, const wchar_t *__s2) __THROW;
+/* Transform S2 into array pointed to by S1 such that if wcscmp is
+   applied to two transformed strings the result is the as applying
+   `wcscoll' to the original strings.  */
+extern size_t wcsxfrm (wchar_t *__restrict __s1,
+		       const wchar_t *__restrict __s2, size_t __n) __THROW;
+
+#ifdef __USE_XOPEN2K8
+/* Similar to the two functions above but take the information from
+   the provided locale and not the global locale.  */
+
+/* Compare S1 and S2, both interpreted as appropriate to the
+   LC_COLLATE category of the given locale.  */
+extern int wcscoll_l (const wchar_t *__s1, const wchar_t *__s2,
+		      locale_t __loc) __THROW;
+
+/* Transform S2 into array pointed to by S1 such that if wcscmp is
+   applied to two transformed strings the result is the as applying
+   `wcscoll' to the original strings.  */
+extern size_t wcsxfrm_l (wchar_t *__s1, const wchar_t *__s2,
+			 size_t __n, locale_t __loc) __THROW;
+
+/* Duplicate S, returning an identical malloc'd string.  */
+extern wchar_t *wcsdup (const wchar_t *__s) __THROW
+  __attribute_malloc__ __attr_dealloc_free;
+#endif
+
+/* Find the first occurrence of WC in WCS.  */
+#ifdef __CORRECT_ISO_CPP_WCHAR_H_PROTO
+extern "C++" wchar_t *wcschr (wchar_t *__wcs, wchar_t __wc)
+     __THROW __asm ("wcschr") __attribute_pure__;
+extern "C++" const wchar_t *wcschr (const wchar_t *__wcs, wchar_t __wc)
+     __THROW __asm ("wcschr") __attribute_pure__;
+#else
+extern wchar_t *wcschr (const wchar_t *__wcs, wchar_t __wc)
+     __THROW __attribute_pure__;
+#endif
+/* Find the last occurrence of WC in WCS.  */
+#ifdef __CORRECT_ISO_CPP_WCHAR_H_PROTO
+extern "C++" wchar_t *wcsrchr (wchar_t *__wcs, wchar_t __wc)
+     __THROW __asm ("wcsrchr") __attribute_pure__;
+extern "C++" const wchar_t *wcsrchr (const wchar_t *__wcs, wchar_t __wc)
+     __THROW __asm ("wcsrchr") __attribute_pure__;
+#else
+extern wchar_t *wcsrchr (const wchar_t *__wcs, wchar_t __wc)
+     __THROW __attribute_pure__;
+#endif
+
+#ifdef __USE_GNU
+/* This function is similar to `wcschr'.  But it returns a pointer to
+   the closing NUL wide character in case C is not found in S.  */
+extern wchar_t *wcschrnul (const wchar_t *__s, wchar_t __wc)
+     __THROW __attribute_pure__;
+#endif
+
+/* Return the length of the initial segmet of WCS which
+   consists entirely of wide characters not in REJECT.  */
+extern size_t wcscspn (const wchar_t *__wcs, const wchar_t *__reject)
+     __THROW __attribute_pure__;
+/* Return the length of the initial segmet of WCS which
+   consists entirely of wide characters in  ACCEPT.  */
+extern size_t wcsspn (const wchar_t *__wcs, const wchar_t *__accept)
+     __THROW __attribute_pure__;
+/* Find the first occurrence in WCS of any character in ACCEPT.  */
+#ifdef __CORRECT_ISO_CPP_WCHAR_H_PROTO
+extern "C++" wchar_t *wcspbrk (wchar_t *__wcs, const wchar_t *__accept)
+     __THROW __asm ("wcspbrk") __attribute_pure__;
+extern "C++" const wchar_t *wcspbrk (const wchar_t *__wcs,
+				     const wchar_t *__accept)
+     __THROW __asm ("wcspbrk") __attribute_pure__;
+#else
+extern wchar_t *wcspbrk (const wchar_t *__wcs, const wchar_t *__accept)
+     __THROW __attribute_pure__;
+#endif
+/* Find the first occurrence of NEEDLE in HAYSTACK.  */
+#ifdef __CORRECT_ISO_CPP_WCHAR_H_PROTO
+extern "C++" wchar_t *wcsstr (wchar_t *__haystack, const wchar_t *__needle)
+     __THROW __asm ("wcsstr") __attribute_pure__;
+extern "C++" const wchar_t *wcsstr (const wchar_t *__haystack,
+				    const wchar_t *__needle)
+     __THROW __asm ("wcsstr") __attribute_pure__;
+#else
+extern wchar_t *wcsstr (const wchar_t *__haystack, const wchar_t *__needle)
+     __THROW __attribute_pure__;
+#endif
+
+/* Divide WCS into tokens separated by characters in DELIM.  */
+extern wchar_t *wcstok (wchar_t *__restrict __s,
+			const wchar_t *__restrict __delim,
+			wchar_t **__restrict __ptr) __THROW;
+
+/* Return the number of wide characters in S.  */
+extern size_t wcslen (const wchar_t *__s) __THROW __attribute_pure__;
+
+#ifdef __USE_XOPEN
+/* Another name for `wcsstr' from XPG4.  */
+# ifdef __CORRECT_ISO_CPP_WCHAR_H_PROTO
+extern "C++" wchar_t *wcswcs (wchar_t *__haystack, const wchar_t *__needle)
+     __THROW __asm ("wcswcs") __attribute_pure__;
+extern "C++" const wchar_t *wcswcs (const wchar_t *__haystack,
+				    const wchar_t *__needle)
+     __THROW __asm ("wcswcs") __attribute_pure__;
+# else
+extern wchar_t *wcswcs (const wchar_t *__haystack, const wchar_t *__needle)
+     __THROW __attribute_pure__;
+# endif
+#endif
+
+#ifdef __USE_XOPEN2K8
+/* Return the number of wide characters in S, but at most MAXLEN.  */
+extern size_t wcsnlen (const wchar_t *__s, size_t __maxlen)
+     __THROW __attribute_pure__;
+#endif
+
+
+/* Search N wide characters of S for C.  */
+#ifdef __CORRECT_ISO_CPP_WCHAR_H_PROTO
+extern "C++" wchar_t *wmemchr (wchar_t *__s, wchar_t __c, size_t __n)
+     __THROW __asm ("wmemchr") __attribute_pure__;
+extern "C++" const wchar_t *wmemchr (const wchar_t *__s, wchar_t __c,
+				     size_t __n)
+     __THROW __asm ("wmemchr") __attribute_pure__;
+#else
+extern wchar_t *wmemchr (const wchar_t *__s, wchar_t __c, size_t __n)
+     __THROW __attribute_pure__;
+#endif
+
+/* Compare N wide characters of S1 and S2.  */
+extern int wmemcmp (const wchar_t *__s1, const wchar_t *__s2, size_t __n)
+     __THROW __attribute_pure__;
+
+/* Copy N wide characters of SRC to DEST.  */
+extern wchar_t *wmemcpy (wchar_t *__restrict __s1,
+			 const wchar_t *__restrict __s2, size_t __n) __THROW;
+
+/* Copy N wide characters of SRC to DEST, guaranteeing
+   correct behavior for overlapping strings.  */
+extern wchar_t *wmemmove (wchar_t *__s1, const wchar_t *__s2, size_t __n)
+     __THROW;
+
+/* Set N wide characters of S to C.  */
+extern wchar_t *wmemset (wchar_t *__s, wchar_t __c, size_t __n) __THROW;
+
+#ifdef __USE_GNU
+/* Copy N wide characters of SRC to DEST and return pointer to following
+   wide character.  */
+extern wchar_t *wmempcpy (wchar_t *__restrict __s1,
+			  const wchar_t *__restrict __s2, size_t __n)
+     __THROW;
+#endif
+
+
+/* Determine whether C constitutes a valid (one-byte) multibyte
+   character.  */
+extern wint_t btowc (int __c) __THROW;
+
+/* Determine whether C corresponds to a member of the extended
+   character set whose multibyte representation is a single byte.  */
+extern int wctob (wint_t __c) __THROW;
+
+/* Determine whether PS points to an object representing the initial
+   state.  */
+extern int mbsinit (const mbstate_t *__ps) __THROW __attribute_pure__;
+
+/* Write wide character representation of multibyte character pointed
+   to by S to PWC.  */
+extern size_t mbrtowc (wchar_t *__restrict __pwc,
+		       const char *__restrict __s, size_t __n,
+		       mbstate_t *__restrict __p) __THROW;
+
+/* Write multibyte representation of wide character WC to S.  */
+extern size_t wcrtomb (char *__restrict __s, wchar_t __wc,
+		       mbstate_t *__restrict __ps) __THROW;
+
+/* Return number of bytes in multibyte character pointed to by S.  */
+extern size_t __mbrlen (const char *__restrict __s, size_t __n,
+			mbstate_t *__restrict __ps) __THROW;
+extern size_t mbrlen (const char *__restrict __s, size_t __n,
+		      mbstate_t *__restrict __ps) __THROW;
+
+#ifdef __USE_EXTERN_INLINES
+/* Define inline function as optimization.  */
+
+/* We can use the BTOWC and WCTOB optimizations since we know that all
+   locales must use ASCII encoding for the values in the ASCII range
+   and because the wchar_t encoding is always ISO 10646.  */
+extern wint_t __btowc_alias (int __c) __asm ("btowc");
+__extern_inline wint_t
+__NTH (btowc (int __c))
+{ return (__builtin_constant_p (__c) && __c >= '\0' && __c <= '\x7f'
+	  ? (wint_t) __c : __btowc_alias (__c)); }
+
+extern int __wctob_alias (wint_t __c) __asm ("wctob");
+__extern_inline int
+__NTH (wctob (wint_t __wc))
+{ return (__builtin_constant_p (__wc) && __wc >= L'\0' && __wc <= L'\x7f'
+	  ? (int) __wc : __wctob_alias (__wc)); }
+
+__extern_inline size_t
+__NTH (mbrlen (const char *__restrict __s, size_t __n,
+	       mbstate_t *__restrict __ps))
+{ return (__ps != NULL
+	  ? mbrtowc (NULL, __s, __n, __ps) : __mbrlen (__s, __n, NULL)); }
+#endif
+
+/* Write wide character representation of multibyte character string
+   SRC to DST.  */
+extern size_t mbsrtowcs (wchar_t *__restrict __dst,
+			 const char **__restrict __src, size_t __len,
+			 mbstate_t *__restrict __ps) __THROW;
+
+/* Write multibyte character representation of wide character string
+   SRC to DST.  */
+extern size_t wcsrtombs (char *__restrict __dst,
+			 const wchar_t **__restrict __src, size_t __len,
+			 mbstate_t *__restrict __ps) __THROW;
+
+
+#ifdef	__USE_XOPEN2K8
+/* Write wide character representation of at most NMC bytes of the
+   multibyte character string SRC to DST.  */
+extern size_t mbsnrtowcs (wchar_t *__restrict __dst,
+			  const char **__restrict __src, size_t __nmc,
+			  size_t __len, mbstate_t *__restrict __ps) __THROW;
+
+/* Write multibyte character representation of at most NWC characters
+   from the wide character string SRC to DST.  */
+extern size_t wcsnrtombs (char *__restrict __dst,
+			  const wchar_t **__restrict __src,
+			  size_t __nwc, size_t __len,
+			  mbstate_t *__restrict __ps) __THROW;
+#endif	/* use POSIX 2008 */
+
+
+/* The following functions are extensions found in X/Open CAE.  */
+#ifdef __USE_XOPEN
+/* Determine number of column positions required for C.  */
+extern int wcwidth (wchar_t __c) __THROW;
+
+/* Determine number of column positions required for first N wide
+   characters (or fewer if S ends before this) in S.  */
+extern int wcswidth (const wchar_t *__s, size_t __n) __THROW;
+#endif	/* Use X/Open.  */
+
+
+/* Convert initial portion of the wide string NPTR to `double'
+   representation.  */
+extern double wcstod (const wchar_t *__restrict __nptr,
+		      wchar_t **__restrict __endptr) __THROW;
+
+#ifdef __USE_ISOC99
+/* Likewise for `float' and `long double' sizes of floating-point numbers.  */
+extern float wcstof (const wchar_t *__restrict __nptr,
+		     wchar_t **__restrict __endptr) __THROW;
+extern long double wcstold (const wchar_t *__restrict __nptr,
+			    wchar_t **__restrict __endptr) __THROW;
+#endif /* C99 */
+
+/* Likewise for `_FloatN' and `_FloatNx' when support is enabled.  */
+
+#if __HAVE_FLOAT16 && defined __USE_GNU
+extern _Float16 wcstof16 (const wchar_t *__restrict __nptr,
+			  wchar_t **__restrict __endptr) __THROW;
+#endif
+
+#if __HAVE_FLOAT32 && defined __USE_GNU
+extern _Float32 wcstof32 (const wchar_t *__restrict __nptr,
+			  wchar_t **__restrict __endptr) __THROW;
+#endif
+
+#if __HAVE_FLOAT64 && defined __USE_GNU
+extern _Float64 wcstof64 (const wchar_t *__restrict __nptr,
+			  wchar_t **__restrict __endptr) __THROW;
+#endif
+
+#if __HAVE_FLOAT128 && defined __USE_GNU
+extern _Float128 wcstof128 (const wchar_t *__restrict __nptr,
+			    wchar_t **__restrict __endptr) __THROW;
+#endif
+
+#if __HAVE_FLOAT32X && defined __USE_GNU
+extern _Float32x wcstof32x (const wchar_t *__restrict __nptr,
+			    wchar_t **__restrict __endptr) __THROW;
+#endif
+
+#if __HAVE_FLOAT64X && defined __USE_GNU
+extern _Float64x wcstof64x (const wchar_t *__restrict __nptr,
+			    wchar_t **__restrict __endptr) __THROW;
+#endif
+
+#if __HAVE_FLOAT128X && defined __USE_GNU
+extern _Float128x wcstof128x (const wchar_t *__restrict __nptr,
+			      wchar_t **__restrict __endptr) __THROW;
+#endif
+
+
+/* Convert initial portion of wide string NPTR to `long int'
+   representation.  */
+extern long int wcstol (const wchar_t *__restrict __nptr,
+			wchar_t **__restrict __endptr, int __base) __THROW;
+
+/* Convert initial portion of wide string NPTR to `unsigned long int'
+   representation.  */
+extern unsigned long int wcstoul (const wchar_t *__restrict __nptr,
+				  wchar_t **__restrict __endptr, int __base)
+     __THROW;
+
+#ifdef __USE_ISOC99
+/* Convert initial portion of wide string NPTR to `long long int'
+   representation.  */
+__extension__
+extern long long int wcstoll (const wchar_t *__restrict __nptr,
+			      wchar_t **__restrict __endptr, int __base)
+     __THROW;
+
+/* Convert initial portion of wide string NPTR to `unsigned long long int'
+   representation.  */
+__extension__
+extern unsigned long long int wcstoull (const wchar_t *__restrict __nptr,
+					wchar_t **__restrict __endptr,
+					int __base) __THROW;
+#endif /* ISO C99.  */
+
+#ifdef __USE_GNU
+/* Convert initial portion of wide string NPTR to `long long int'
+   representation.  */
+__extension__
+extern long long int wcstoq (const wchar_t *__restrict __nptr,
+			     wchar_t **__restrict __endptr, int __base)
+     __THROW;
+
+/* Convert initial portion of wide string NPTR to `unsigned long long int'
+   representation.  */
+__extension__
+extern unsigned long long int wcstouq (const wchar_t *__restrict __nptr,
+				       wchar_t **__restrict __endptr,
+				       int __base) __THROW;
+#endif /* Use GNU.  */
+
+#ifdef __USE_GNU
+/* Parallel versions of the functions above which take the locale to
+   use as an additional parameter.  These are GNU extensions inspired
+   by the POSIX.1-2008 extended locale API.  */
+extern long int wcstol_l (const wchar_t *__restrict __nptr,
+			  wchar_t **__restrict __endptr, int __base,
+			  locale_t __loc) __THROW;
+
+extern unsigned long int wcstoul_l (const wchar_t *__restrict __nptr,
+				    wchar_t **__restrict __endptr,
+				    int __base, locale_t __loc) __THROW;
+
+__extension__
+extern long long int wcstoll_l (const wchar_t *__restrict __nptr,
+				wchar_t **__restrict __endptr,
+				int __base, locale_t __loc) __THROW;
+
+__extension__
+extern unsigned long long int wcstoull_l (const wchar_t *__restrict __nptr,
+					  wchar_t **__restrict __endptr,
+					  int __base, locale_t __loc)
+     __THROW;
+
+extern double wcstod_l (const wchar_t *__restrict __nptr,
+			wchar_t **__restrict __endptr, locale_t __loc)
+     __THROW;
+
+extern float wcstof_l (const wchar_t *__restrict __nptr,
+		       wchar_t **__restrict __endptr, locale_t __loc)
+     __THROW;
+
+extern long double wcstold_l (const wchar_t *__restrict __nptr,
+			      wchar_t **__restrict __endptr,
+			      locale_t __loc) __THROW;
+
+# if __HAVE_FLOAT16
+extern _Float16 wcstof16_l (const wchar_t *__restrict __nptr,
+			    wchar_t **__restrict __endptr,
+			    locale_t __loc) __THROW;
+# endif
+
+# if __HAVE_FLOAT32
+extern _Float32 wcstof32_l (const wchar_t *__restrict __nptr,
+			    wchar_t **__restrict __endptr,
+			    locale_t __loc) __THROW;
+# endif
+
+# if __HAVE_FLOAT64
+extern _Float64 wcstof64_l (const wchar_t *__restrict __nptr,
+			    wchar_t **__restrict __endptr,
+			    locale_t __loc) __THROW;
+# endif
+
+# if __HAVE_FLOAT128
+extern _Float128 wcstof128_l (const wchar_t *__restrict __nptr,
+			      wchar_t **__restrict __endptr,
+			      locale_t __loc) __THROW;
+# endif
+
+# if __HAVE_FLOAT32X
+extern _Float32x wcstof32x_l (const wchar_t *__restrict __nptr,
+			      wchar_t **__restrict __endptr,
+			      locale_t __loc) __THROW;
+# endif
+
+# if __HAVE_FLOAT64X
+extern _Float64x wcstof64x_l (const wchar_t *__restrict __nptr,
+			      wchar_t **__restrict __endptr,
+			      locale_t __loc) __THROW;
+# endif
+
+# if __HAVE_FLOAT128X
+extern _Float128x wcstof128x_l (const wchar_t *__restrict __nptr,
+				wchar_t **__restrict __endptr,
+				locale_t __loc) __THROW;
+# endif
+#endif	/* use GNU */
+
+
+#ifdef __USE_XOPEN2K8
+/* Copy SRC to DEST, returning the address of the terminating L'\0' in
+   DEST.  */
+extern wchar_t *wcpcpy (wchar_t *__restrict __dest,
+			const wchar_t *__restrict __src) __THROW;
+
+/* Copy no more than N characters of SRC to DEST, returning the address of
+   the last character written into DEST.  */
+extern wchar_t *wcpncpy (wchar_t *__restrict __dest,
+			 const wchar_t *__restrict __src, size_t __n)
+     __THROW;
+#endif
+
+
+/* Wide character I/O functions.  */
+
+#if defined __USE_XOPEN2K8 || __GLIBC_USE (LIB_EXT2)
+# ifndef __attr_dealloc_fclose
+#   if defined __has_builtin
+#     if __has_builtin (__builtin_fclose)
+/* If the attribute macro hasn't been defined yet (by <stdio.h>) and
+   fclose is a built-in, use it.  */
+#      define __attr_dealloc_fclose __attr_dealloc (__builtin_fclose, 1)
+#     endif
+#   endif
+# endif
+# ifndef __attr_dealloc_fclose
+#  define __attr_dealloc_fclose /* empty */
+# endif
+
+/* Like OPEN_MEMSTREAM, but the stream is wide oriented and produces
+   a wide character string.  */
+extern __FILE *open_wmemstream (wchar_t **__bufloc, size_t *__sizeloc) __THROW
+  __attribute_malloc__ __attr_dealloc_fclose;
+#endif
+
+#if defined __USE_ISOC95 || defined __USE_UNIX98
+
+/* Select orientation for stream.  */
+extern int fwide (__FILE *__fp, int __mode) __THROW;
+
+
+/* Write formatted output to STREAM.
+
+   This function is a possible cancellation point and therefore not
+   marked with __THROW.  */
+extern int fwprintf (__FILE *__restrict __stream,
+		     const wchar_t *__restrict __format, ...)
+     /* __attribute__ ((__format__ (__wprintf__, 2, 3))) */;
+/* Write formatted output to stdout.
+
+   This function is a possible cancellation point and therefore not
+   marked with __THROW.  */
+extern int wprintf (const wchar_t *__restrict __format, ...)
+     /* __attribute__ ((__format__ (__wprintf__, 1, 2))) */;
+/* Write formatted output of at most N characters to S.  */
+extern int swprintf (wchar_t *__restrict __s, size_t __n,
+		     const wchar_t *__restrict __format, ...)
+     __THROW /* __attribute__ ((__format__ (__wprintf__, 3, 4))) */;
+
+/* Write formatted output to S from argument list ARG.
+
+   This function is a possible cancellation point and therefore not
+   marked with __THROW.  */
+extern int vfwprintf (__FILE *__restrict __s,
+		      const wchar_t *__restrict __format,
+		      __gnuc_va_list __arg)
+     /* __attribute__ ((__format__ (__wprintf__, 2, 0))) */;
+/* Write formatted output to stdout from argument list ARG.
+
+   This function is a possible cancellation point and therefore not
+   marked with __THROW.  */
+extern int vwprintf (const wchar_t *__restrict __format,
+		     __gnuc_va_list __arg)
+     /* __attribute__ ((__format__ (__wprintf__, 1, 0))) */;
+/* Write formatted output of at most N character to S from argument
+   list ARG.  */
+extern int vswprintf (wchar_t *__restrict __s, size_t __n,
+		      const wchar_t *__restrict __format,
+		      __gnuc_va_list __arg)
+     __THROW /* __attribute__ ((__format__ (__wprintf__, 3, 0))) */;
+
+
+/* Read formatted input from STREAM.
+
+   This function is a possible cancellation point and therefore not
+   marked with __THROW.  */
+extern int fwscanf (__FILE *__restrict __stream,
+		    const wchar_t *__restrict __format, ...)
+     /* __attribute__ ((__format__ (__wscanf__, 2, 3))) */;
+/* Read formatted input from stdin.
+
+   This function is a possible cancellation point and therefore not
+   marked with __THROW.  */
+extern int wscanf (const wchar_t *__restrict __format, ...)
+     /* __attribute__ ((__format__ (__wscanf__, 1, 2))) */;
+/* Read formatted input from S.  */
+extern int swscanf (const wchar_t *__restrict __s,
+		    const wchar_t *__restrict __format, ...)
+     __THROW /* __attribute__ ((__format__ (__wscanf__, 2, 3))) */;
+
+/* For historical reasons, the C99-compliant versions of the scanf
+   functions are at alternative names.  When __LDBL_COMPAT or
+   __LDOUBLE_REDIRECTS_TO_FLOAT128_ABI are in effect, this is handled in
+   bits/wchar-ldbl.h.  */
+#if !__GLIBC_USE (DEPRECATED_SCANF) && !defined __LDBL_COMPAT \
+     && __LDOUBLE_REDIRECTS_TO_FLOAT128_ABI == 0
+#  ifdef __REDIRECT
+extern int __REDIRECT (fwscanf, (__FILE *__restrict __stream,
+				 const wchar_t *__restrict __format, ...),
+		       __isoc99_fwscanf)
+     /* __attribute__ ((__format__ (__wscanf__, 2, 3))) */;
+extern int __REDIRECT (wscanf, (const wchar_t *__restrict __format, ...),
+		       __isoc99_wscanf)
+     /* __attribute__ ((__format__ (__wscanf__, 1, 2))) */;
+extern int __REDIRECT_NTH (swscanf, (const wchar_t *__restrict __s,
+				     const wchar_t *__restrict __format,
+				     ...), __isoc99_swscanf)
+     /* __attribute__ ((__format__ (__wscanf__, 2, 3))) */;
+#  else
+extern int __isoc99_fwscanf (__FILE *__restrict __stream,
+			     const wchar_t *__restrict __format, ...);
+extern int __isoc99_wscanf (const wchar_t *__restrict __format, ...);
+extern int __isoc99_swscanf (const wchar_t *__restrict __s,
+			     const wchar_t *__restrict __format, ...)
+     __THROW;
+#   define fwscanf __isoc99_fwscanf
+#   define wscanf __isoc99_wscanf
+#   define swscanf __isoc99_swscanf
+#  endif
+# endif
+
+#endif /* Use ISO C95, C99 and Unix98. */
+
+#ifdef __USE_ISOC99
+/* Read formatted input from S into argument list ARG.
+
+   This function is a possible cancellation point and therefore not
+   marked with __THROW.  */
+extern int vfwscanf (__FILE *__restrict __s,
+		     const wchar_t *__restrict __format,
+		     __gnuc_va_list __arg)
+     /* __attribute__ ((__format__ (__wscanf__, 2, 0))) */;
+/* Read formatted input from stdin into argument list ARG.
+
+   This function is a possible cancellation point and therefore not
+   marked with __THROW.  */
+extern int vwscanf (const wchar_t *__restrict __format,
+		    __gnuc_va_list __arg)
+     /* __attribute__ ((__format__ (__wscanf__, 1, 0))) */;
+/* Read formatted input from S into argument list ARG.  */
+extern int vswscanf (const wchar_t *__restrict __s,
+		     const wchar_t *__restrict __format,
+		     __gnuc_va_list __arg)
+     __THROW /* __attribute__ ((__format__ (__wscanf__, 2, 0))) */;
+
+/* Same redirection as above for the v*wscanf family.  */
+# if !__GLIBC_USE (DEPRECATED_SCANF) \
+     && (!defined __LDBL_COMPAT || !defined __REDIRECT) \
+     && (defined __STRICT_ANSI__ || defined __USE_XOPEN2K) \
+     && __LDOUBLE_REDIRECTS_TO_FLOAT128_ABI == 0
+#  ifdef __REDIRECT
+extern int __REDIRECT (vfwscanf, (__FILE *__restrict __s,
+				  const wchar_t *__restrict __format,
+				  __gnuc_va_list __arg), __isoc99_vfwscanf)
+     /* __attribute__ ((__format__ (__wscanf__, 2, 0))) */;
+extern int __REDIRECT (vwscanf, (const wchar_t *__restrict __format,
+				 __gnuc_va_list __arg), __isoc99_vwscanf)
+     /* __attribute__ ((__format__ (__wscanf__, 1, 0))) */;
+extern int __REDIRECT_NTH (vswscanf, (const wchar_t *__restrict __s,
+				      const wchar_t *__restrict __format,
+				      __gnuc_va_list __arg), __isoc99_vswscanf)
+     /* __attribute__ ((__format__ (__wscanf__, 2, 0))) */;
+#  else
+extern int __isoc99_vfwscanf (__FILE *__restrict __s,
+			      const wchar_t *__restrict __format,
+			      __gnuc_va_list __arg);
+extern int __isoc99_vwscanf (const wchar_t *__restrict __format,
+			     __gnuc_va_list __arg);
+extern int __isoc99_vswscanf (const wchar_t *__restrict __s,
+			      const wchar_t *__restrict __format,
+			      __gnuc_va_list __arg) __THROW;
+#   define vfwscanf __isoc99_vfwscanf
+#   define vwscanf __isoc99_vwscanf
+#   define vswscanf __isoc99_vswscanf
+#  endif
+# endif
+
+#endif /* Use ISO C99. */
+
+
+/* Read a character from STREAM.
+
+   These functions are possible cancellation points and therefore not
+   marked with __THROW.  */
+extern wint_t fgetwc (__FILE *__stream);
+extern wint_t getwc (__FILE *__stream);
+
+/* Read a character from stdin.
+
+   This function is a possible cancellation point and therefore not
+   marked with __THROW.  */
+extern wint_t getwchar (void);
+
+
+/* Write a character to STREAM.
+
+   These functions are possible cancellation points and therefore not
+   marked with __THROW.  */
+extern wint_t fputwc (wchar_t __wc, __FILE *__stream);
+extern wint_t putwc (wchar_t __wc, __FILE *__stream);
+
+/* Write a character to stdout.
+
+   This function is a possible cancellation point and therefore not
+   marked with __THROW.  */
+extern wint_t putwchar (wchar_t __wc);
+
+
+/* Get a newline-terminated wide character string of finite length
+   from STREAM.
+
+   This function is a possible cancellation point and therefore not
+   marked with __THROW.  */
+extern wchar_t *fgetws (wchar_t *__restrict __ws, int __n,
+			__FILE *__restrict __stream);
+
+/* Write a string to STREAM.
+
+   This function is a possible cancellation point and therefore not
+   marked with __THROW.  */
+extern int fputws (const wchar_t *__restrict __ws,
+		   __FILE *__restrict __stream);
+
+
+/* Push a character back onto the input buffer of STREAM.
+
+   This function is a possible cancellation point and therefore not
+   marked with __THROW.  */
+extern wint_t ungetwc (wint_t __wc, __FILE *__stream);
+
+
+#ifdef __USE_GNU
+/* These are defined to be equivalent to the `char' functions defined
+   in POSIX.1:1996.
+
+   These functions are not part of POSIX and therefore no official
+   cancellation point.  But due to similarity with an POSIX interface
+   or due to the implementation they are cancellation points and
+   therefore not marked with __THROW.  */
+extern wint_t getwc_unlocked (__FILE *__stream);
+extern wint_t getwchar_unlocked (void);
+
+/* This is the wide character version of a GNU extension.
+
+   This function is not part of POSIX and therefore no official
+   cancellation point.  But due to similarity with an POSIX interface
+   or due to the implementation it is a cancellation point and
+   therefore not marked with __THROW.  */
+extern wint_t fgetwc_unlocked (__FILE *__stream);
+
+/* Faster version when locking is not necessary.
+
+   This function is not part of POSIX and therefore no official
+   cancellation point.  But due to similarity with an POSIX interface
+   or due to the implementation it is a cancellation point and
+   therefore not marked with __THROW.  */
+extern wint_t fputwc_unlocked (wchar_t __wc, __FILE *__stream);
+
+/* These are defined to be equivalent to the `char' functions defined
+   in POSIX.1:1996.
+
+   These functions are not part of POSIX and therefore no official
+   cancellation point.  But due to similarity with an POSIX interface
+   or due to the implementation they are cancellation points and
+   therefore not marked with __THROW.  */
+extern wint_t putwc_unlocked (wchar_t __wc, __FILE *__stream);
+extern wint_t putwchar_unlocked (wchar_t __wc);
+
+
+/* This function does the same as `fgetws' but does not lock the stream.
+
+   This function is not part of POSIX and therefore no official
+   cancellation point.  But due to similarity with an POSIX interface
+   or due to the implementation it is a cancellation point and
+   therefore not marked with __THROW.  */
+extern wchar_t *fgetws_unlocked (wchar_t *__restrict __ws, int __n,
+				 __FILE *__restrict __stream);
+
+/* This function does the same as `fputws' but does not lock the stream.
+
+   This function is not part of POSIX and therefore no official
+   cancellation point.  But due to similarity with an POSIX interface
+   or due to the implementation it is a cancellation point and
+   therefore not marked with __THROW.  */
+extern int fputws_unlocked (const wchar_t *__restrict __ws,
+			    __FILE *__restrict __stream);
+#endif
+
+
+/* Format TP into S according to FORMAT.
+   Write no more than MAXSIZE wide characters and return the number
+   of wide characters written, or 0 if it would exceed MAXSIZE.  */
+extern size_t wcsftime (wchar_t *__restrict __s, size_t __maxsize,
+			const wchar_t *__restrict __format,
+			const struct tm *__restrict __tp) __THROW;
+
+# ifdef __USE_GNU
+/* Similar to `wcsftime' but takes the information from
+   the provided locale and not the global locale.  */
+extern size_t wcsftime_l (wchar_t *__restrict __s, size_t __maxsize,
+			  const wchar_t *__restrict __format,
+			  const struct tm *__restrict __tp,
+			  locale_t __loc) __THROW;
+# endif
+
+/* Define some macros helping to catch buffer overflows.  */
+#if __USE_FORTIFY_LEVEL > 0 && defined __fortify_function
+/* Declare all functions from bits/wchar2-decl.h first.  */
+# include <bits/wchar2-decl.h>
+#endif
+
+/* The following headers provide asm redirections.  These redirections must
+   appear before the first usage of these functions, e.g. in bits/wchar.h.  */
+#if defined __LDBL_COMPAT || __LDOUBLE_REDIRECTS_TO_FLOAT128_ABI == 1
+# include <bits/wchar-ldbl.h>
+#endif
+
+#if __USE_FORTIFY_LEVEL > 0 && defined __fortify_function
+/* Now include the function definitions and redirects too.  */
+# include <bits/wchar2.h>
+#endif
+
+__END_DECLS
+
+#endif /* wchar.h  */
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@wctype.h b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@wctype.h
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index 0000000000000000000000000000000000000000..7e87fd3bf984e7c4e68665e5ee57c6d5fd20ed49
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@1zsc48wwlplpkzms83m7zr94xnfalq2q-glibc-2.35-224-dev@include@wctype.h
@@ -0,0 +1,148 @@
+/* Copyright (C) 1996-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+/*
+ *	ISO C99 Standard: 7.25
+ *	Wide character classification and mapping utilities  <wctype.h>
+ */
+
+#ifndef _WCTYPE_H
+#define _WCTYPE_H 1
+
+#include <features.h>
+#include <bits/types.h>
+#include <bits/types/wint_t.h>
+
+/* Constant expression of type `wint_t' whose value does not correspond
+   to any member of the extended character set.  */
+#ifndef WEOF
+# define WEOF (0xffffffffu)
+#endif
+
+/* Some definitions from this header also appear in <wchar.h> in
+   Unix98 mode.  */
+#include <bits/wctype-wchar.h>
+
+/*
+ * Extensible wide-character mapping functions: 7.15.3.2.
+ */
+
+__BEGIN_DECLS
+
+/* Scalar type that can hold values which represent locale-specific
+   character mappings.  */
+typedef const __int32_t *wctrans_t;
+
+/* Construct value that describes a mapping between wide characters
+   identified by the string argument PROPERTY.  */
+extern wctrans_t wctrans (const char *__property) __THROW;
+
+/* Map the wide character WC using the mapping described by DESC.  */
+extern wint_t towctrans (wint_t __wc, wctrans_t __desc) __THROW;
+
+# ifdef __USE_XOPEN2K8
+/* POSIX.1-2008 extended locale interface (see locale.h).  */
+#  include <bits/types/locale_t.h>
+
+/* Test for any wide character for which `iswalpha' or `iswdigit' is
+   true.  */
+extern int iswalnum_l (wint_t __wc, locale_t __locale) __THROW;
+
+/* Test for any wide character for which `iswupper' or 'iswlower' is
+   true, or any wide character that is one of a locale-specific set of
+   wide-characters for which none of `iswcntrl', `iswdigit',
+   `iswpunct', or `iswspace' is true.  */
+extern int iswalpha_l (wint_t __wc, locale_t __locale) __THROW;
+
+/* Test for any control wide character.  */
+extern int iswcntrl_l (wint_t __wc, locale_t __locale) __THROW;
+
+/* Test for any wide character that corresponds to a decimal-digit
+   character.  */
+extern int iswdigit_l (wint_t __wc, locale_t __locale) __THROW;
+
+/* Test for any wide character for which `iswprint' is true and
+   `iswspace' is false.  */
+extern int iswgraph_l (wint_t __wc, locale_t __locale) __THROW;
+
+/* Test for any wide character that corresponds to a lowercase letter
+   or is one of a locale-specific set of wide characters for which
+   none of `iswcntrl', `iswdigit', `iswpunct', or `iswspace' is true.  */
+extern int iswlower_l (wint_t __wc, locale_t __locale) __THROW;
+
+/* Test for any printing wide character.  */
+extern int iswprint_l (wint_t __wc, locale_t __locale) __THROW;
+
+/* Test for any printing wide character that is one of a
+   locale-specific et of wide characters for which neither `iswspace'
+   nor `iswalnum' is true.  */
+extern int iswpunct_l (wint_t __wc, locale_t __locale) __THROW;
+
+/* Test for any wide character that corresponds to a locale-specific
+   set of wide characters for which none of `iswalnum', `iswgraph', or
+   `iswpunct' is true.  */
+extern int iswspace_l (wint_t __wc, locale_t __locale) __THROW;
+
+/* Test for any wide character that corresponds to an uppercase letter
+   or is one of a locale-specific set of wide character for which none
+   of `iswcntrl', `iswdigit', `iswpunct', or `iswspace' is true.  */
+extern int iswupper_l (wint_t __wc, locale_t __locale) __THROW;
+
+/* Test for any wide character that corresponds to a hexadecimal-digit
+   character equivalent to that performed be the functions described
+   in the previous subclause.  */
+extern int iswxdigit_l (wint_t __wc, locale_t __locale) __THROW;
+
+/* Test for any wide character that corresponds to a standard blank
+   wide character or a locale-specific set of wide characters for
+   which `iswalnum' is false.  */
+extern int iswblank_l (wint_t __wc, locale_t __locale) __THROW;
+
+/* Construct value that describes a class of wide characters identified
+   by the string argument PROPERTY.  */
+extern wctype_t wctype_l (const char *__property, locale_t __locale)
+     __THROW;
+
+/* Determine whether the wide-character WC has the property described by
+   DESC.  */
+extern int iswctype_l (wint_t __wc, wctype_t __desc, locale_t __locale)
+     __THROW;
+
+/*
+ * Wide-character case-mapping functions.
+ */
+
+/* Converts an uppercase letter to the corresponding lowercase letter.  */
+extern wint_t towlower_l (wint_t __wc, locale_t __locale) __THROW;
+
+/* Converts an lowercase letter to the corresponding uppercase letter.  */
+extern wint_t towupper_l (wint_t __wc, locale_t __locale) __THROW;
+
+/* Construct value that describes a mapping between wide characters
+   identified by the string argument PROPERTY.  */
+extern wctrans_t wctrans_l (const char *__property, locale_t __locale)
+     __THROW;
+
+/* Map the wide character WC using the mapping described by DESC.  */
+extern wint_t towctrans_l (wint_t __wc, wctrans_t __desc,
+			   locale_t __locale) __THROW;
+
+# endif /* Use POSIX 2008.  */
+
+__END_DECLS
+
+#endif /* wctype.h  */
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@fa0byasfkms4k570jm47b7sb9lkrj73v-linux-headers-6.2@include@asm-generic@errno-base.h b/.ccls-cache/@@root@gpt-vue/@nix@store@fa0byasfkms4k570jm47b7sb9lkrj73v-linux-headers-6.2@include@asm-generic@errno-base.h
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@fa0byasfkms4k570jm47b7sb9lkrj73v-linux-headers-6.2@include@asm-generic@errno-base.h
@@ -0,0 +1,40 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+#ifndef _ASM_GENERIC_ERRNO_BASE_H
+#define _ASM_GENERIC_ERRNO_BASE_H
+
+#define	EPERM		 1	/* Operation not permitted */
+#define	ENOENT		 2	/* No such file or directory */
+#define	ESRCH		 3	/* No such process */
+#define	EINTR		 4	/* Interrupted system call */
+#define	EIO		 5	/* I/O error */
+#define	ENXIO		 6	/* No such device or address */
+#define	E2BIG		 7	/* Argument list too long */
+#define	ENOEXEC		 8	/* Exec format error */
+#define	EBADF		 9	/* Bad file number */
+#define	ECHILD		10	/* No child processes */
+#define	EAGAIN		11	/* Try again */
+#define	ENOMEM		12	/* Out of memory */
+#define	EACCES		13	/* Permission denied */
+#define	EFAULT		14	/* Bad address */
+#define	ENOTBLK		15	/* Block device required */
+#define	EBUSY		16	/* Device or resource busy */
+#define	EEXIST		17	/* File exists */
+#define	EXDEV		18	/* Cross-device link */
+#define	ENODEV		19	/* No such device */
+#define	ENOTDIR		20	/* Not a directory */
+#define	EISDIR		21	/* Is a directory */
+#define	EINVAL		22	/* Invalid argument */
+#define	ENFILE		23	/* File table overflow */
+#define	EMFILE		24	/* Too many open files */
+#define	ENOTTY		25	/* Not a typewriter */
+#define	ETXTBSY		26	/* Text file busy */
+#define	EFBIG		27	/* File too large */
+#define	ENOSPC		28	/* No space left on device */
+#define	ESPIPE		29	/* Illegal seek */
+#define	EROFS		30	/* Read-only file system */
+#define	EMLINK		31	/* Too many links */
+#define	EPIPE		32	/* Broken pipe */
+#define	EDOM		33	/* Math argument out of domain of func */
+#define	ERANGE		34	/* Math result not representable */
+
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@fa0byasfkms4k570jm47b7sb9lkrj73v-linux-headers-6.2@include@asm-generic@errno-base.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@fa0byasfkms4k570jm47b7sb9lkrj73v-linux-headers-6.2@include@asm-generic@errno-base.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@fa0byasfkms4k570jm47b7sb9lkrj73v-linux-headers-6.2@include@asm-generic@errno.h b/.ccls-cache/@@root@gpt-vue/@nix@store@fa0byasfkms4k570jm47b7sb9lkrj73v-linux-headers-6.2@include@asm-generic@errno.h
new file mode 100644
index 0000000000000000000000000000000000000000..cf9c51ac49f97efd8d5aed07cf4fca2d9a368515
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@fa0byasfkms4k570jm47b7sb9lkrj73v-linux-headers-6.2@include@asm-generic@errno.h
@@ -0,0 +1,123 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+#ifndef _ASM_GENERIC_ERRNO_H
+#define _ASM_GENERIC_ERRNO_H
+
+#include <asm-generic/errno-base.h>
+
+#define	EDEADLK		35	/* Resource deadlock would occur */
+#define	ENAMETOOLONG	36	/* File name too long */
+#define	ENOLCK		37	/* No record locks available */
+
+/*
+ * This error code is special: arch syscall entry code will return
+ * -ENOSYS if users try to call a syscall that doesn't exist.  To keep
+ * failures of syscalls that really do exist distinguishable from
+ * failures due to attempts to use a nonexistent syscall, syscall
+ * implementations should refrain from returning -ENOSYS.
+ */
+#define	ENOSYS		38	/* Invalid system call number */
+
+#define	ENOTEMPTY	39	/* Directory not empty */
+#define	ELOOP		40	/* Too many symbolic links encountered */
+#define	EWOULDBLOCK	EAGAIN	/* Operation would block */
+#define	ENOMSG		42	/* No message of desired type */
+#define	EIDRM		43	/* Identifier removed */
+#define	ECHRNG		44	/* Channel number out of range */
+#define	EL2NSYNC	45	/* Level 2 not synchronized */
+#define	EL3HLT		46	/* Level 3 halted */
+#define	EL3RST		47	/* Level 3 reset */
+#define	ELNRNG		48	/* Link number out of range */
+#define	EUNATCH		49	/* Protocol driver not attached */
+#define	ENOCSI		50	/* No CSI structure available */
+#define	EL2HLT		51	/* Level 2 halted */
+#define	EBADE		52	/* Invalid exchange */
+#define	EBADR		53	/* Invalid request descriptor */
+#define	EXFULL		54	/* Exchange full */
+#define	ENOANO		55	/* No anode */
+#define	EBADRQC		56	/* Invalid request code */
+#define	EBADSLT		57	/* Invalid slot */
+
+#define	EDEADLOCK	EDEADLK
+
+#define	EBFONT		59	/* Bad font file format */
+#define	ENOSTR		60	/* Device not a stream */
+#define	ENODATA		61	/* No data available */
+#define	ETIME		62	/* Timer expired */
+#define	ENOSR		63	/* Out of streams resources */
+#define	ENONET		64	/* Machine is not on the network */
+#define	ENOPKG		65	/* Package not installed */
+#define	EREMOTE		66	/* Object is remote */
+#define	ENOLINK		67	/* Link has been severed */
+#define	EADV		68	/* Advertise error */
+#define	ESRMNT		69	/* Srmount error */
+#define	ECOMM		70	/* Communication error on send */
+#define	EPROTO		71	/* Protocol error */
+#define	EMULTIHOP	72	/* Multihop attempted */
+#define	EDOTDOT		73	/* RFS specific error */
+#define	EBADMSG		74	/* Not a data message */
+#define	EOVERFLOW	75	/* Value too large for defined data type */
+#define	ENOTUNIQ	76	/* Name not unique on network */
+#define	EBADFD		77	/* File descriptor in bad state */
+#define	EREMCHG		78	/* Remote address changed */
+#define	ELIBACC		79	/* Can not access a needed shared library */
+#define	ELIBBAD		80	/* Accessing a corrupted shared library */
+#define	ELIBSCN		81	/* .lib section in a.out corrupted */
+#define	ELIBMAX		82	/* Attempting to link in too many shared libraries */
+#define	ELIBEXEC	83	/* Cannot exec a shared library directly */
+#define	EILSEQ		84	/* Illegal byte sequence */
+#define	ERESTART	85	/* Interrupted system call should be restarted */
+#define	ESTRPIPE	86	/* Streams pipe error */
+#define	EUSERS		87	/* Too many users */
+#define	ENOTSOCK	88	/* Socket operation on non-socket */
+#define	EDESTADDRREQ	89	/* Destination address required */
+#define	EMSGSIZE	90	/* Message too long */
+#define	EPROTOTYPE	91	/* Protocol wrong type for socket */
+#define	ENOPROTOOPT	92	/* Protocol not available */
+#define	EPROTONOSUPPORT	93	/* Protocol not supported */
+#define	ESOCKTNOSUPPORT	94	/* Socket type not supported */
+#define	EOPNOTSUPP	95	/* Operation not supported on transport endpoint */
+#define	EPFNOSUPPORT	96	/* Protocol family not supported */
+#define	EAFNOSUPPORT	97	/* Address family not supported by protocol */
+#define	EADDRINUSE	98	/* Address already in use */
+#define	EADDRNOTAVAIL	99	/* Cannot assign requested address */
+#define	ENETDOWN	100	/* Network is down */
+#define	ENETUNREACH	101	/* Network is unreachable */
+#define	ENETRESET	102	/* Network dropped connection because of reset */
+#define	ECONNABORTED	103	/* Software caused connection abort */
+#define	ECONNRESET	104	/* Connection reset by peer */
+#define	ENOBUFS		105	/* No buffer space available */
+#define	EISCONN		106	/* Transport endpoint is already connected */
+#define	ENOTCONN	107	/* Transport endpoint is not connected */
+#define	ESHUTDOWN	108	/* Cannot send after transport endpoint shutdown */
+#define	ETOOMANYREFS	109	/* Too many references: cannot splice */
+#define	ETIMEDOUT	110	/* Connection timed out */
+#define	ECONNREFUSED	111	/* Connection refused */
+#define	EHOSTDOWN	112	/* Host is down */
+#define	EHOSTUNREACH	113	/* No route to host */
+#define	EALREADY	114	/* Operation already in progress */
+#define	EINPROGRESS	115	/* Operation now in progress */
+#define	ESTALE		116	/* Stale file handle */
+#define	EUCLEAN		117	/* Structure needs cleaning */
+#define	ENOTNAM		118	/* Not a XENIX named type file */
+#define	ENAVAIL		119	/* No XENIX semaphores available */
+#define	EISNAM		120	/* Is a named type file */
+#define	EREMOTEIO	121	/* Remote I/O error */
+#define	EDQUOT		122	/* Quota exceeded */
+
+#define	ENOMEDIUM	123	/* No medium found */
+#define	EMEDIUMTYPE	124	/* Wrong medium type */
+#define	ECANCELED	125	/* Operation Canceled */
+#define	ENOKEY		126	/* Required key not available */
+#define	EKEYEXPIRED	127	/* Key has expired */
+#define	EKEYREVOKED	128	/* Key has been revoked */
+#define	EKEYREJECTED	129	/* Key was rejected by service */
+
+/* for robust mutexes */
+#define	EOWNERDEAD	130	/* Owner died */
+#define	ENOTRECOVERABLE	131	/* State not recoverable */
+
+#define ERFKILL		132	/* Operation not possible due to RF-kill */
+
+#define EHWPOISON	133	/* Memory page has hardware error */
+
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@fa0byasfkms4k570jm47b7sb9lkrj73v-linux-headers-6.2@include@asm-generic@errno.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@fa0byasfkms4k570jm47b7sb9lkrj73v-linux-headers-6.2@include@asm-generic@errno.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@fa0byasfkms4k570jm47b7sb9lkrj73v-linux-headers-6.2@include@asm@errno.h b/.ccls-cache/@@root@gpt-vue/@nix@store@fa0byasfkms4k570jm47b7sb9lkrj73v-linux-headers-6.2@include@asm@errno.h
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index 0000000000000000000000000000000000000000..4c82b503d92ffabcc6eb558a50ae5d6dba8a5f7c
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@fa0byasfkms4k570jm47b7sb9lkrj73v-linux-headers-6.2@include@asm@errno.h
@@ -0,0 +1 @@
+#include <asm-generic/errno.h>
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@fa0byasfkms4k570jm47b7sb9lkrj73v-linux-headers-6.2@include@asm@errno.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@fa0byasfkms4k570jm47b7sb9lkrj73v-linux-headers-6.2@include@asm@errno.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@fa0byasfkms4k570jm47b7sb9lkrj73v-linux-headers-6.2@include@linux@close_range.h b/.ccls-cache/@@root@gpt-vue/@nix@store@fa0byasfkms4k570jm47b7sb9lkrj73v-linux-headers-6.2@include@linux@close_range.h
new file mode 100644
index 0000000000000000000000000000000000000000..af78ebfec7dd0204045780f22e3f8dc36f527e27
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@fa0byasfkms4k570jm47b7sb9lkrj73v-linux-headers-6.2@include@linux@close_range.h
@@ -0,0 +1,12 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+#ifndef _LINUX_CLOSE_RANGE_H
+#define _LINUX_CLOSE_RANGE_H
+
+/* Unshare the file descriptor table before closing file descriptors. */
+#define CLOSE_RANGE_UNSHARE	(1U << 1)
+
+/* Set the FD_CLOEXEC bit instead of closing the file descriptor. */
+#define CLOSE_RANGE_CLOEXEC	(1U << 2)
+
+#endif /* _LINUX_CLOSE_RANGE_H */
+
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@fa0byasfkms4k570jm47b7sb9lkrj73v-linux-headers-6.2@include@linux@close_range.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@fa0byasfkms4k570jm47b7sb9lkrj73v-linux-headers-6.2@include@linux@close_range.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@fa0byasfkms4k570jm47b7sb9lkrj73v-linux-headers-6.2@include@linux@errno.h b/.ccls-cache/@@root@gpt-vue/@nix@store@fa0byasfkms4k570jm47b7sb9lkrj73v-linux-headers-6.2@include@linux@errno.h
new file mode 100644
index 0000000000000000000000000000000000000000..70f2bd34e3354bc551ae6d0481f752c642ad6a40
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@fa0byasfkms4k570jm47b7sb9lkrj73v-linux-headers-6.2@include@linux@errno.h
@@ -0,0 +1 @@
+#include <asm/errno.h>
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@fa0byasfkms4k570jm47b7sb9lkrj73v-linux-headers-6.2@include@linux@errno.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@fa0byasfkms4k570jm47b7sb9lkrj73v-linux-headers-6.2@include@linux@errno.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@fa0byasfkms4k570jm47b7sb9lkrj73v-linux-headers-6.2@include@linux@limits.h b/.ccls-cache/@@root@gpt-vue/@nix@store@fa0byasfkms4k570jm47b7sb9lkrj73v-linux-headers-6.2@include@linux@limits.h
new file mode 100644
index 0000000000000000000000000000000000000000..c3547f07605c9e2ca28e4ced0fbba545b55d21a6
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@fa0byasfkms4k570jm47b7sb9lkrj73v-linux-headers-6.2@include@linux@limits.h
@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+#ifndef _LINUX_LIMITS_H
+#define _LINUX_LIMITS_H
+
+#define NR_OPEN	        1024
+
+#define NGROUPS_MAX    65536	/* supplemental group IDs are available */
+#define ARG_MAX       131072	/* # bytes of args + environ for exec() */
+#define LINK_MAX         127	/* # links a file may have */
+#define MAX_CANON        255	/* size of the canonical input queue */
+#define MAX_INPUT        255	/* size of the type-ahead buffer */
+#define NAME_MAX         255	/* # chars in a file name */
+#define PATH_MAX        4096	/* # chars in a path name including nul */
+#define PIPE_BUF        4096	/* # bytes in atomic write to a pipe */
+#define XATTR_NAME_MAX   255	/* # chars in an extended attribute name */
+#define XATTR_SIZE_MAX 65536	/* size of an extended attribute value (64k) */
+#define XATTR_LIST_MAX 65536	/* size of extended attribute namelist (64k) */
+
+#define RTSIG_MAX	  32
+
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@fa0byasfkms4k570jm47b7sb9lkrj73v-linux-headers-6.2@include@linux@limits.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@fa0byasfkms4k570jm47b7sb9lkrj73v-linux-headers-6.2@include@linux@limits.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@algorithm b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@algorithm
new file mode 100644
index 0000000000000000000000000000000000000000..e2cfd7ca662f849bf00c92bf229d628ad313d41b
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@algorithm
@@ -0,0 +1,85 @@
+// <algorithm> -*- C++ -*-
+
+// Copyright (C) 2001-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/*
+ *
+ * Copyright (c) 1994
+ * Hewlett-Packard Company
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Hewlett-Packard Company makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ *
+ *
+ * Copyright (c) 1996,1997
+ * Silicon Graphics Computer Systems, Inc.
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Silicon Graphics makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ */
+
+/** @file include/algorithm
+ *  This is a Standard C++ Library header.
+ */
+
+#ifndef _GLIBCXX_ALGORITHM
+#define _GLIBCXX_ALGORITHM 1
+
+#pragma GCC system_header
+
+#include <bits/stl_algobase.h>
+#include <bits/stl_algo.h>
+#if __cplusplus > 201703L
+# include <bits/ranges_algo.h>
+#endif
+
+#if __cplusplus > 201402L
+// Parallel STL algorithms
+# if _PSTL_EXECUTION_POLICIES_DEFINED
+// If <execution> has already been included, pull in implementations
+#  include <pstl/glue_algorithm_impl.h>
+#  else
+// Otherwise just pull in forward declarations
+#    include <pstl/glue_algorithm_defs.h>
+#    define _PSTL_ALGORITHM_FORWARD_DECLARED 1
+#  endif
+
+// Feature test macro for parallel algorithms
+# define __cpp_lib_parallel_algorithm 201603L
+#endif // C++17
+
+#ifdef _GLIBCXX_PARALLEL
+# include <parallel/algorithm>
+#endif
+
+#endif /* _GLIBCXX_ALGORITHM */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@algorithm.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@algorithm.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@array b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@array
new file mode 100644
index 0000000000000000000000000000000000000000..e45143fb329964418b8d6e30153de3c5dd0edba6
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@array
@@ -0,0 +1,499 @@
+// <array> -*- C++ -*-
+
+// Copyright (C) 2007-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file include/array
+ *  This is a Standard C++ Library header.
+ */
+
+#ifndef _GLIBCXX_ARRAY
+#define _GLIBCXX_ARRAY 1
+
+#pragma GCC system_header
+
+#if __cplusplus < 201103L
+# include <bits/c++0x_warning.h>
+#else
+
+#include <compare>
+#include <initializer_list>
+
+#include <type_traits>
+#include <bits/functexcept.h>
+#include <bits/stl_algobase.h>
+#include <bits/range_access.h> // std::begin, std::end etc.
+#include <bits/utility.h>      // std::index_sequence, std::tuple_size
+#include <debug/assertions.h>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  template<typename _Tp, std::size_t _Nm>
+    struct __array_traits
+    {
+      typedef _Tp _Type[_Nm];
+      typedef __is_swappable<_Tp> _Is_swappable;
+      typedef __is_nothrow_swappable<_Tp> _Is_nothrow_swappable;
+
+      static constexpr _Tp&
+      _S_ref(const _Type& __t, std::size_t __n) noexcept
+      { return const_cast<_Tp&>(__t[__n]); }
+
+      static constexpr _Tp*
+      _S_ptr(const _Type& __t) noexcept
+      { return const_cast<_Tp*>(__t); }
+    };
+
+ template<typename _Tp>
+   struct __array_traits<_Tp, 0>
+   {
+     struct _Type { };
+     typedef true_type _Is_swappable;
+     typedef true_type _Is_nothrow_swappable;
+
+     static constexpr _Tp&
+     _S_ref(const _Type&, std::size_t) noexcept
+     { return *static_cast<_Tp*>(nullptr); }
+
+     static constexpr _Tp*
+     _S_ptr(const _Type&) noexcept
+     { return nullptr; }
+   };
+
+  /**
+   *  @brief A standard container for storing a fixed size sequence of elements.
+   *
+   *  @ingroup sequences
+   *
+   *  Meets the requirements of a <a href="tables.html#65">container</a>, a
+   *  <a href="tables.html#66">reversible container</a>, and a
+   *  <a href="tables.html#67">sequence</a>.
+   *
+   *  Sets support random access iterators.
+   *
+   *  @tparam  Tp  Type of element. Required to be a complete type.
+   *  @tparam  Nm  Number of elements.
+  */
+  template<typename _Tp, std::size_t _Nm>
+    struct array
+    {
+      typedef _Tp 	    			      value_type;
+      typedef value_type*			      pointer;
+      typedef const value_type*                       const_pointer;
+      typedef value_type&                   	      reference;
+      typedef const value_type&             	      const_reference;
+      typedef value_type*          		      iterator;
+      typedef const value_type*			      const_iterator;
+      typedef std::size_t                    	      size_type;
+      typedef std::ptrdiff_t                   	      difference_type;
+      typedef std::reverse_iterator<iterator>	      reverse_iterator;
+      typedef std::reverse_iterator<const_iterator>   const_reverse_iterator;
+
+      // Support for zero-sized arrays mandatory.
+      typedef __array_traits<_Tp, _Nm> _AT_Type;
+      typename _AT_Type::_Type                         _M_elems;
+
+      // No explicit construct/copy/destroy for aggregate type.
+
+      // DR 776.
+      _GLIBCXX20_CONSTEXPR void
+      fill(const value_type& __u)
+      { std::fill_n(begin(), size(), __u); }
+
+      _GLIBCXX20_CONSTEXPR void
+      swap(array& __other)
+      noexcept(_AT_Type::_Is_nothrow_swappable::value)
+      { std::swap_ranges(begin(), end(), __other.begin()); }
+
+      // Iterators.
+      [[__gnu__::__const__, __nodiscard__]]
+      _GLIBCXX17_CONSTEXPR iterator
+      begin() noexcept
+      { return iterator(data()); }
+
+      [[__nodiscard__]]
+      _GLIBCXX17_CONSTEXPR const_iterator
+      begin() const noexcept
+      { return const_iterator(data()); }
+
+      [[__gnu__::__const__, __nodiscard__]]
+      _GLIBCXX17_CONSTEXPR iterator
+      end() noexcept
+      { return iterator(data() + _Nm); }
+
+      [[__nodiscard__]]
+      _GLIBCXX17_CONSTEXPR const_iterator
+      end() const noexcept
+      { return const_iterator(data() + _Nm); }
+
+      [[__gnu__::__const__, __nodiscard__]]
+      _GLIBCXX17_CONSTEXPR reverse_iterator
+      rbegin() noexcept
+      { return reverse_iterator(end()); }
+
+      [[__nodiscard__]]
+      _GLIBCXX17_CONSTEXPR const_reverse_iterator
+      rbegin() const noexcept
+      { return const_reverse_iterator(end()); }
+
+      [[__gnu__::__const__, __nodiscard__]]
+      _GLIBCXX17_CONSTEXPR reverse_iterator
+      rend() noexcept
+      { return reverse_iterator(begin()); }
+
+      [[__nodiscard__]]
+      _GLIBCXX17_CONSTEXPR const_reverse_iterator
+      rend() const noexcept
+      { return const_reverse_iterator(begin()); }
+
+      [[__nodiscard__]]
+      _GLIBCXX17_CONSTEXPR const_iterator
+      cbegin() const noexcept
+      { return const_iterator(data()); }
+
+      [[__nodiscard__]]
+      _GLIBCXX17_CONSTEXPR const_iterator
+      cend() const noexcept
+      { return const_iterator(data() + _Nm); }
+
+      [[__nodiscard__]]
+      _GLIBCXX17_CONSTEXPR const_reverse_iterator
+      crbegin() const noexcept
+      { return const_reverse_iterator(end()); }
+
+      [[__nodiscard__]]
+      _GLIBCXX17_CONSTEXPR const_reverse_iterator
+      crend() const noexcept
+      { return const_reverse_iterator(begin()); }
+
+      // Capacity.
+      [[__gnu__::__const__, __nodiscard__]]
+      constexpr size_type
+      size() const noexcept { return _Nm; }
+
+      [[__gnu__::__const__, __nodiscard__]]
+      constexpr size_type
+      max_size() const noexcept { return _Nm; }
+
+      [[__gnu__::__const__, __nodiscard__]]
+      constexpr bool
+      empty() const noexcept { return size() == 0; }
+
+      // Element access.
+      [[__nodiscard__]]
+      _GLIBCXX17_CONSTEXPR reference
+      operator[](size_type __n) noexcept
+      {
+	__glibcxx_requires_subscript(__n);
+	return _AT_Type::_S_ref(_M_elems, __n);
+      }
+
+      [[__nodiscard__]]
+      constexpr const_reference
+      operator[](size_type __n) const noexcept
+      {
+#if __cplusplus >= 201402L
+	__glibcxx_requires_subscript(__n);
+#endif
+	return _AT_Type::_S_ref(_M_elems, __n);
+      }
+
+      _GLIBCXX17_CONSTEXPR reference
+      at(size_type __n)
+      {
+	if (__n >= _Nm)
+	  std::__throw_out_of_range_fmt(__N("array::at: __n (which is %zu) "
+					    ">= _Nm (which is %zu)"),
+					__n, _Nm);
+	return _AT_Type::_S_ref(_M_elems, __n);
+      }
+
+      constexpr const_reference
+      at(size_type __n) const
+      {
+	// Result of conditional expression must be an lvalue so use
+	// boolean ? lvalue : (throw-expr, lvalue)
+	return __n < _Nm ? _AT_Type::_S_ref(_M_elems, __n)
+	  : (std::__throw_out_of_range_fmt(__N("array::at: __n (which is %zu) "
+					       ">= _Nm (which is %zu)"),
+					   __n, _Nm),
+	     _AT_Type::_S_ref(_M_elems, 0));
+      }
+
+      [[__nodiscard__]]
+      _GLIBCXX17_CONSTEXPR reference
+      front() noexcept
+      {
+	__glibcxx_requires_nonempty();
+	return *begin();
+      }
+
+      [[__nodiscard__]]
+      constexpr const_reference
+      front() const noexcept
+      {
+#if __cplusplus >= 201402L
+	__glibcxx_requires_nonempty();
+#endif
+	return _AT_Type::_S_ref(_M_elems, 0);
+      }
+
+      [[__nodiscard__]]
+      _GLIBCXX17_CONSTEXPR reference
+      back() noexcept
+      {
+	__glibcxx_requires_nonempty();
+	return _Nm ? *(end() - 1) : *end();
+      }
+
+      [[__nodiscard__]]
+      constexpr const_reference
+      back() const noexcept
+      {
+#if __cplusplus >= 201402L
+	__glibcxx_requires_nonempty();
+#endif
+	return _Nm ? _AT_Type::_S_ref(_M_elems, _Nm - 1)
+ 	           : _AT_Type::_S_ref(_M_elems, 0);
+      }
+
+      [[__gnu__::__const__, __nodiscard__]]
+      _GLIBCXX17_CONSTEXPR pointer
+      data() noexcept
+      { return _AT_Type::_S_ptr(_M_elems); }
+
+      [[__nodiscard__]]
+      _GLIBCXX17_CONSTEXPR const_pointer
+      data() const noexcept
+      { return _AT_Type::_S_ptr(_M_elems); }
+    };
+
+#if __cpp_deduction_guides >= 201606
+  template<typename _Tp, typename... _Up>
+    array(_Tp, _Up...)
+      -> array<enable_if_t<(is_same_v<_Tp, _Up> && ...), _Tp>,
+	       1 + sizeof...(_Up)>;
+#endif
+
+  // Array comparisons.
+  template<typename _Tp, std::size_t _Nm>
+    [[__nodiscard__]]
+    _GLIBCXX20_CONSTEXPR
+    inline bool
+    operator==(const array<_Tp, _Nm>& __one, const array<_Tp, _Nm>& __two)
+    { return std::equal(__one.begin(), __one.end(), __two.begin()); }
+
+#if __cpp_lib_three_way_comparison && __cpp_lib_concepts
+  template<typename _Tp, size_t _Nm>
+    [[nodiscard]]
+    constexpr __detail::__synth3way_t<_Tp>
+    operator<=>(const array<_Tp, _Nm>& __a, const array<_Tp, _Nm>& __b)
+    {
+      if constexpr (_Nm && __is_memcmp_ordered<_Tp>::__value)
+	if (!std::__is_constant_evaluated())
+	  {
+	    constexpr size_t __n = _Nm * sizeof(_Tp);
+	    return __builtin_memcmp(__a.data(), __b.data(), __n) <=> 0;
+	  }
+
+      for (size_t __i = 0; __i < _Nm; ++__i)
+	{
+	  auto __c = __detail::__synth3way(__a[__i], __b[__i]);
+	  if (__c != 0)
+	    return __c;
+	}
+      return strong_ordering::equal;
+    }
+#else
+  template<typename _Tp, std::size_t _Nm>
+    [[__nodiscard__]]
+    _GLIBCXX20_CONSTEXPR
+    inline bool
+    operator!=(const array<_Tp, _Nm>& __one, const array<_Tp, _Nm>& __two)
+    { return !(__one == __two); }
+
+  template<typename _Tp, std::size_t _Nm>
+    [[__nodiscard__]]
+    _GLIBCXX20_CONSTEXPR
+    inline bool
+    operator<(const array<_Tp, _Nm>& __a, const array<_Tp, _Nm>& __b)
+    {
+      return std::lexicographical_compare(__a.begin(), __a.end(),
+					  __b.begin(), __b.end());
+    }
+
+  template<typename _Tp, std::size_t _Nm>
+    [[__nodiscard__]]
+    _GLIBCXX20_CONSTEXPR
+    inline bool
+    operator>(const array<_Tp, _Nm>& __one, const array<_Tp, _Nm>& __two)
+    { return __two < __one; }
+
+  template<typename _Tp, std::size_t _Nm>
+    [[__nodiscard__]]
+    _GLIBCXX20_CONSTEXPR
+    inline bool
+    operator<=(const array<_Tp, _Nm>& __one, const array<_Tp, _Nm>& __two)
+    { return !(__one > __two); }
+
+  template<typename _Tp, std::size_t _Nm>
+    [[__nodiscard__]]
+    _GLIBCXX20_CONSTEXPR
+    inline bool
+    operator>=(const array<_Tp, _Nm>& __one, const array<_Tp, _Nm>& __two)
+    { return !(__one < __two); }
+#endif // three_way_comparison && concepts
+
+  // Specialized algorithms.
+  template<typename _Tp, std::size_t _Nm>
+    _GLIBCXX20_CONSTEXPR
+    inline
+#if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11
+    // Constrained free swap overload, see p0185r1
+    typename enable_if<
+      __array_traits<_Tp, _Nm>::_Is_swappable::value
+    >::type
+#else
+    void
+#endif
+    swap(array<_Tp, _Nm>& __one, array<_Tp, _Nm>& __two)
+    noexcept(noexcept(__one.swap(__two)))
+    { __one.swap(__two); }
+
+#if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11
+  template<typename _Tp, std::size_t _Nm>
+    typename enable_if<
+      !__array_traits<_Tp, _Nm>::_Is_swappable::value>::type
+    swap(array<_Tp, _Nm>&, array<_Tp, _Nm>&) = delete;
+#endif
+
+  template<std::size_t _Int, typename _Tp, std::size_t _Nm>
+    [[__nodiscard__]]
+    constexpr _Tp&
+    get(array<_Tp, _Nm>& __arr) noexcept
+    {
+      static_assert(_Int < _Nm, "array index is within bounds");
+      return __array_traits<_Tp, _Nm>::_S_ref(__arr._M_elems, _Int);
+    }
+
+  template<std::size_t _Int, typename _Tp, std::size_t _Nm>
+    [[__nodiscard__]]
+    constexpr _Tp&&
+    get(array<_Tp, _Nm>&& __arr) noexcept
+    {
+      static_assert(_Int < _Nm, "array index is within bounds");
+      return std::move(std::get<_Int>(__arr));
+    }
+
+  template<std::size_t _Int, typename _Tp, std::size_t _Nm>
+    [[__nodiscard__]]
+    constexpr const _Tp&
+    get(const array<_Tp, _Nm>& __arr) noexcept
+    {
+      static_assert(_Int < _Nm, "array index is within bounds");
+      return __array_traits<_Tp, _Nm>::_S_ref(__arr._M_elems, _Int);
+    }
+
+  template<std::size_t _Int, typename _Tp, std::size_t _Nm>
+    [[__nodiscard__]]
+    constexpr const _Tp&&
+    get(const array<_Tp, _Nm>&& __arr) noexcept
+    {
+      static_assert(_Int < _Nm, "array index is within bounds");
+      return std::move(std::get<_Int>(__arr));
+    }
+
+#if __cplusplus > 201703L
+#define __cpp_lib_to_array 201907L
+
+  template<bool _Move = false, typename _Tp, size_t... _Idx>
+    constexpr array<remove_cv_t<_Tp>, sizeof...(_Idx)>
+    __to_array(_Tp (&__a)[sizeof...(_Idx)], index_sequence<_Idx...>)
+    {
+      if constexpr (_Move)
+	return {{std::move(__a[_Idx])...}};
+      else
+	return {{__a[_Idx]...}};
+    }
+
+  template<typename _Tp, size_t _Nm>
+    [[nodiscard]]
+    constexpr array<remove_cv_t<_Tp>, _Nm>
+    to_array(_Tp (&__a)[_Nm])
+    noexcept(is_nothrow_constructible_v<_Tp, _Tp&>)
+    {
+      static_assert(!is_array_v<_Tp>);
+      static_assert(is_constructible_v<_Tp, _Tp&>);
+      if constexpr (is_constructible_v<_Tp, _Tp&>)
+	return __to_array(__a, make_index_sequence<_Nm>{});
+      __builtin_unreachable(); // FIXME: see PR c++/91388
+    }
+
+  template<typename _Tp, size_t _Nm>
+    [[nodiscard]]
+    constexpr array<remove_cv_t<_Tp>, _Nm>
+    to_array(_Tp (&&__a)[_Nm])
+    noexcept(is_nothrow_move_constructible_v<_Tp>)
+    {
+      static_assert(!is_array_v<_Tp>);
+      static_assert(is_move_constructible_v<_Tp>);
+      if constexpr (is_move_constructible_v<_Tp>)
+	return __to_array<1>(__a, make_index_sequence<_Nm>{});
+      __builtin_unreachable(); // FIXME: see PR c++/91388
+    }
+#endif // C++20
+
+  // Tuple interface to class template array.
+
+  /// Partial specialization for std::array
+  template<typename _Tp, size_t _Nm>
+    struct tuple_size<array<_Tp, _Nm>>
+    : public integral_constant<size_t, _Nm> { };
+
+  /// Partial specialization for std::array
+  template<size_t _Ind, typename _Tp, size_t _Nm>
+    struct tuple_element<_Ind, array<_Tp, _Nm>>
+    {
+      static_assert(_Ind < _Nm, "array index is in range");
+      using type = _Tp;
+    };
+
+#if __cplusplus >= 201703L
+  template<typename _Tp, size_t _Nm>
+    inline constexpr size_t tuple_size_v<array<_Tp, _Nm>> = _Nm;
+
+  template<typename _Tp, size_t _Nm>
+    inline constexpr size_t tuple_size_v<const array<_Tp, _Nm>> = _Nm;
+#endif
+
+  template<typename _Tp, size_t _Nm>
+    struct __is_tuple_like_impl<array<_Tp, _Nm>> : true_type
+    { };
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif // C++11
+
+#endif // _GLIBCXX_ARRAY
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@array.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@array.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@atomic b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@atomic
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@@ -0,0 +1,1654 @@
+// -*- C++ -*- header.
+
+// Copyright (C) 2008-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file include/atomic
+ *  This is a Standard C++ Library header.
+ */
+
+// Based on "C++ Atomic Types and Operations" by Hans Boehm and Lawrence Crowl.
+// http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2007/n2427.html
+
+#ifndef _GLIBCXX_ATOMIC
+#define _GLIBCXX_ATOMIC 1
+
+#pragma GCC system_header
+
+#if __cplusplus < 201103L
+# include <bits/c++0x_warning.h>
+#else
+
+#include <bits/atomic_base.h>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /**
+   * @addtogroup atomics
+   * @{
+   */
+
+#if __cplusplus >= 201703L
+# define __cpp_lib_atomic_is_always_lock_free 201603L
+#endif
+
+  template<typename _Tp>
+    struct atomic;
+
+  /// atomic<bool>
+  // NB: No operators or fetch-operations for this type.
+  template<>
+  struct atomic<bool>
+  {
+    using value_type = bool;
+
+  private:
+    __atomic_base<bool>	_M_base;
+
+  public:
+    atomic() noexcept = default;
+    ~atomic() noexcept = default;
+    atomic(const atomic&) = delete;
+    atomic& operator=(const atomic&) = delete;
+    atomic& operator=(const atomic&) volatile = delete;
+
+    constexpr atomic(bool __i) noexcept : _M_base(__i) { }
+
+    bool
+    operator=(bool __i) noexcept
+    { return _M_base.operator=(__i); }
+
+    bool
+    operator=(bool __i) volatile noexcept
+    { return _M_base.operator=(__i); }
+
+    operator bool() const noexcept
+    { return _M_base.load(); }
+
+    operator bool() const volatile noexcept
+    { return _M_base.load(); }
+
+    bool
+    is_lock_free() const noexcept { return _M_base.is_lock_free(); }
+
+    bool
+    is_lock_free() const volatile noexcept { return _M_base.is_lock_free(); }
+
+#if __cplusplus >= 201703L
+    static constexpr bool is_always_lock_free = ATOMIC_BOOL_LOCK_FREE == 2;
+#endif
+
+    void
+    store(bool __i, memory_order __m = memory_order_seq_cst) noexcept
+    { _M_base.store(__i, __m); }
+
+    void
+    store(bool __i, memory_order __m = memory_order_seq_cst) volatile noexcept
+    { _M_base.store(__i, __m); }
+
+    bool
+    load(memory_order __m = memory_order_seq_cst) const noexcept
+    { return _M_base.load(__m); }
+
+    bool
+    load(memory_order __m = memory_order_seq_cst) const volatile noexcept
+    { return _M_base.load(__m); }
+
+    bool
+    exchange(bool __i, memory_order __m = memory_order_seq_cst) noexcept
+    { return _M_base.exchange(__i, __m); }
+
+    bool
+    exchange(bool __i,
+	     memory_order __m = memory_order_seq_cst) volatile noexcept
+    { return _M_base.exchange(__i, __m); }
+
+    bool
+    compare_exchange_weak(bool& __i1, bool __i2, memory_order __m1,
+			  memory_order __m2) noexcept
+    { return _M_base.compare_exchange_weak(__i1, __i2, __m1, __m2); }
+
+    bool
+    compare_exchange_weak(bool& __i1, bool __i2, memory_order __m1,
+			  memory_order __m2) volatile noexcept
+    { return _M_base.compare_exchange_weak(__i1, __i2, __m1, __m2); }
+
+    bool
+    compare_exchange_weak(bool& __i1, bool __i2,
+			  memory_order __m = memory_order_seq_cst) noexcept
+    { return _M_base.compare_exchange_weak(__i1, __i2, __m); }
+
+    bool
+    compare_exchange_weak(bool& __i1, bool __i2,
+		     memory_order __m = memory_order_seq_cst) volatile noexcept
+    { return _M_base.compare_exchange_weak(__i1, __i2, __m); }
+
+    bool
+    compare_exchange_strong(bool& __i1, bool __i2, memory_order __m1,
+			    memory_order __m2) noexcept
+    { return _M_base.compare_exchange_strong(__i1, __i2, __m1, __m2); }
+
+    bool
+    compare_exchange_strong(bool& __i1, bool __i2, memory_order __m1,
+			    memory_order __m2) volatile noexcept
+    { return _M_base.compare_exchange_strong(__i1, __i2, __m1, __m2); }
+
+    bool
+    compare_exchange_strong(bool& __i1, bool __i2,
+			    memory_order __m = memory_order_seq_cst) noexcept
+    { return _M_base.compare_exchange_strong(__i1, __i2, __m); }
+
+    bool
+    compare_exchange_strong(bool& __i1, bool __i2,
+		    memory_order __m = memory_order_seq_cst) volatile noexcept
+    { return _M_base.compare_exchange_strong(__i1, __i2, __m); }
+
+#if __cpp_lib_atomic_wait
+    void
+    wait(bool __old, memory_order __m = memory_order_seq_cst) const noexcept
+    { _M_base.wait(__old, __m); }
+
+    // TODO add const volatile overload
+
+    void
+    notify_one() noexcept
+    { _M_base.notify_one(); }
+
+    void
+    notify_all() noexcept
+    { _M_base.notify_all(); }
+#endif // __cpp_lib_atomic_wait
+  };
+
+#if __cplusplus <= 201703L
+# define _GLIBCXX20_INIT(I)
+#else
+# define _GLIBCXX20_INIT(I) = I
+#endif
+
+  /**
+   *  @brief Generic atomic type, primary class template.
+   *
+   *  @tparam _Tp  Type to be made atomic, must be trivially copyable.
+   */
+  template<typename _Tp>
+    struct atomic
+    {
+      using value_type = _Tp;
+
+    private:
+      // Align 1/2/4/8/16-byte types to at least their size.
+      static constexpr int _S_min_alignment
+	= (sizeof(_Tp) & (sizeof(_Tp) - 1)) || sizeof(_Tp) > 16
+	? 0 : sizeof(_Tp);
+
+      static constexpr int _S_alignment
+        = _S_min_alignment > alignof(_Tp) ? _S_min_alignment : alignof(_Tp);
+
+      alignas(_S_alignment) _Tp _M_i _GLIBCXX20_INIT(_Tp());
+
+      static_assert(__is_trivially_copyable(_Tp),
+		    "std::atomic requires a trivially copyable type");
+
+      static_assert(sizeof(_Tp) > 0,
+		    "Incomplete or zero-sized types are not supported");
+
+#if __cplusplus > 201703L
+      static_assert(is_copy_constructible_v<_Tp>);
+      static_assert(is_move_constructible_v<_Tp>);
+      static_assert(is_copy_assignable_v<_Tp>);
+      static_assert(is_move_assignable_v<_Tp>);
+#endif
+
+    public:
+      atomic() = default;
+      ~atomic() noexcept = default;
+      atomic(const atomic&) = delete;
+      atomic& operator=(const atomic&) = delete;
+      atomic& operator=(const atomic&) volatile = delete;
+
+      constexpr atomic(_Tp __i) noexcept : _M_i(__i) { }
+
+      operator _Tp() const noexcept
+      { return load(); }
+
+      operator _Tp() const volatile noexcept
+      { return load(); }
+
+      _Tp
+      operator=(_Tp __i) noexcept
+      { store(__i); return __i; }
+
+      _Tp
+      operator=(_Tp __i) volatile noexcept
+      { store(__i); return __i; }
+
+      bool
+      is_lock_free() const noexcept
+      {
+	// Produce a fake, minimally aligned pointer.
+	return __atomic_is_lock_free(sizeof(_M_i),
+	    reinterpret_cast<void *>(-_S_alignment));
+      }
+
+      bool
+      is_lock_free() const volatile noexcept
+      {
+	// Produce a fake, minimally aligned pointer.
+	return __atomic_is_lock_free(sizeof(_M_i),
+	    reinterpret_cast<void *>(-_S_alignment));
+      }
+
+#if __cplusplus >= 201703L
+      static constexpr bool is_always_lock_free
+	= __atomic_always_lock_free(sizeof(_M_i), 0);
+#endif
+
+      void
+      store(_Tp __i, memory_order __m = memory_order_seq_cst) noexcept
+      {
+	__atomic_store(std::__addressof(_M_i), std::__addressof(__i), int(__m));
+      }
+
+      void
+      store(_Tp __i, memory_order __m = memory_order_seq_cst) volatile noexcept
+      {
+	__atomic_store(std::__addressof(_M_i), std::__addressof(__i), int(__m));
+      }
+
+      _Tp
+      load(memory_order __m = memory_order_seq_cst) const noexcept
+      {
+	alignas(_Tp) unsigned char __buf[sizeof(_Tp)];
+	_Tp* __ptr = reinterpret_cast<_Tp*>(__buf);
+	__atomic_load(std::__addressof(_M_i), __ptr, int(__m));
+	return *__ptr;
+      }
+
+      _Tp
+      load(memory_order __m = memory_order_seq_cst) const volatile noexcept
+      {
+        alignas(_Tp) unsigned char __buf[sizeof(_Tp)];
+	_Tp* __ptr = reinterpret_cast<_Tp*>(__buf);
+	__atomic_load(std::__addressof(_M_i), __ptr, int(__m));
+	return *__ptr;
+      }
+
+      _Tp
+      exchange(_Tp __i, memory_order __m = memory_order_seq_cst) noexcept
+      {
+        alignas(_Tp) unsigned char __buf[sizeof(_Tp)];
+	_Tp* __ptr = reinterpret_cast<_Tp*>(__buf);
+	__atomic_exchange(std::__addressof(_M_i), std::__addressof(__i),
+			  __ptr, int(__m));
+	return *__ptr;
+      }
+
+      _Tp
+      exchange(_Tp __i,
+	       memory_order __m = memory_order_seq_cst) volatile noexcept
+      {
+        alignas(_Tp) unsigned char __buf[sizeof(_Tp)];
+	_Tp* __ptr = reinterpret_cast<_Tp*>(__buf);
+	__atomic_exchange(std::__addressof(_M_i), std::__addressof(__i),
+			  __ptr, int(__m));
+	return *__ptr;
+      }
+
+      bool
+      compare_exchange_weak(_Tp& __e, _Tp __i, memory_order __s,
+			    memory_order __f) noexcept
+      {
+	__glibcxx_assert(__is_valid_cmpexch_failure_order(__f));
+
+	return __atomic_compare_exchange(std::__addressof(_M_i),
+					 std::__addressof(__e),
+					 std::__addressof(__i),
+					 true, int(__s), int(__f));
+      }
+
+      bool
+      compare_exchange_weak(_Tp& __e, _Tp __i, memory_order __s,
+			    memory_order __f) volatile noexcept
+      {
+	__glibcxx_assert(__is_valid_cmpexch_failure_order(__f));
+
+	return __atomic_compare_exchange(std::__addressof(_M_i),
+					 std::__addressof(__e),
+					 std::__addressof(__i),
+					 true, int(__s), int(__f));
+      }
+
+      bool
+      compare_exchange_weak(_Tp& __e, _Tp __i,
+			    memory_order __m = memory_order_seq_cst) noexcept
+      { return compare_exchange_weak(__e, __i, __m,
+                                     __cmpexch_failure_order(__m)); }
+
+      bool
+      compare_exchange_weak(_Tp& __e, _Tp __i,
+		     memory_order __m = memory_order_seq_cst) volatile noexcept
+      { return compare_exchange_weak(__e, __i, __m,
+                                     __cmpexch_failure_order(__m)); }
+
+      bool
+      compare_exchange_strong(_Tp& __e, _Tp __i, memory_order __s,
+			      memory_order __f) noexcept
+      {
+	__glibcxx_assert(__is_valid_cmpexch_failure_order(__f));
+
+	return __atomic_compare_exchange(std::__addressof(_M_i),
+					 std::__addressof(__e),
+					 std::__addressof(__i),
+					 false, int(__s), int(__f));
+      }
+
+      bool
+      compare_exchange_strong(_Tp& __e, _Tp __i, memory_order __s,
+			      memory_order __f) volatile noexcept
+      {
+	__glibcxx_assert(__is_valid_cmpexch_failure_order(__f));
+
+	return __atomic_compare_exchange(std::__addressof(_M_i),
+					 std::__addressof(__e),
+					 std::__addressof(__i),
+					 false, int(__s), int(__f));
+      }
+
+      bool
+      compare_exchange_strong(_Tp& __e, _Tp __i,
+			       memory_order __m = memory_order_seq_cst) noexcept
+      { return compare_exchange_strong(__e, __i, __m,
+                                       __cmpexch_failure_order(__m)); }
+
+      bool
+      compare_exchange_strong(_Tp& __e, _Tp __i,
+		     memory_order __m = memory_order_seq_cst) volatile noexcept
+      { return compare_exchange_strong(__e, __i, __m,
+                                       __cmpexch_failure_order(__m)); }
+
+#if __cpp_lib_atomic_wait 
+    void
+    wait(_Tp __old, memory_order __m = memory_order_seq_cst) const noexcept
+    {
+      std::__atomic_wait_address_v(&_M_i, __old,
+			 [__m, this] { return this->load(__m); });
+    }
+
+    // TODO add const volatile overload
+
+    void
+    notify_one() noexcept
+    { std::__atomic_notify_address(&_M_i, false); }
+
+    void
+    notify_all() noexcept
+    { std::__atomic_notify_address(&_M_i, true); }
+#endif // __cpp_lib_atomic_wait 
+
+    };
+#undef _GLIBCXX20_INIT
+
+  /// Partial specialization for pointer types.
+  template<typename _Tp>
+    struct atomic<_Tp*>
+    {
+      using value_type = _Tp*;
+      using difference_type = ptrdiff_t;
+
+      typedef _Tp* 			__pointer_type;
+      typedef __atomic_base<_Tp*>	__base_type;
+      __base_type			_M_b;
+
+      atomic() noexcept = default;
+      ~atomic() noexcept = default;
+      atomic(const atomic&) = delete;
+      atomic& operator=(const atomic&) = delete;
+      atomic& operator=(const atomic&) volatile = delete;
+
+      constexpr atomic(__pointer_type __p) noexcept : _M_b(__p) { }
+
+      operator __pointer_type() const noexcept
+      { return __pointer_type(_M_b); }
+
+      operator __pointer_type() const volatile noexcept
+      { return __pointer_type(_M_b); }
+
+      __pointer_type
+      operator=(__pointer_type __p) noexcept
+      { return _M_b.operator=(__p); }
+
+      __pointer_type
+      operator=(__pointer_type __p) volatile noexcept
+      { return _M_b.operator=(__p); }
+
+      __pointer_type
+      operator++(int) noexcept
+      {
+#if __cplusplus >= 201703L
+	static_assert( is_object<_Tp>::value, "pointer to object type" );
+#endif
+	return _M_b++;
+      }
+
+      __pointer_type
+      operator++(int) volatile noexcept
+      {
+#if __cplusplus >= 201703L
+	static_assert( is_object<_Tp>::value, "pointer to object type" );
+#endif
+	return _M_b++;
+      }
+
+      __pointer_type
+      operator--(int) noexcept
+      {
+#if __cplusplus >= 201703L
+	static_assert( is_object<_Tp>::value, "pointer to object type" );
+#endif
+	return _M_b--;
+      }
+
+      __pointer_type
+      operator--(int) volatile noexcept
+      {
+#if __cplusplus >= 201703L
+	static_assert( is_object<_Tp>::value, "pointer to object type" );
+#endif
+	return _M_b--;
+      }
+
+      __pointer_type
+      operator++() noexcept
+      {
+#if __cplusplus >= 201703L
+	static_assert( is_object<_Tp>::value, "pointer to object type" );
+#endif
+	return ++_M_b;
+      }
+
+      __pointer_type
+      operator++() volatile noexcept
+      {
+#if __cplusplus >= 201703L
+	static_assert( is_object<_Tp>::value, "pointer to object type" );
+#endif
+	return ++_M_b;
+      }
+
+      __pointer_type
+      operator--() noexcept
+      {
+#if __cplusplus >= 201703L
+	static_assert( is_object<_Tp>::value, "pointer to object type" );
+#endif
+	return --_M_b;
+      }
+
+      __pointer_type
+      operator--() volatile noexcept
+      {
+#if __cplusplus >= 201703L
+	static_assert( is_object<_Tp>::value, "pointer to object type" );
+#endif
+	return --_M_b;
+      }
+
+      __pointer_type
+      operator+=(ptrdiff_t __d) noexcept
+      {
+#if __cplusplus >= 201703L
+	static_assert( is_object<_Tp>::value, "pointer to object type" );
+#endif
+	return _M_b.operator+=(__d);
+      }
+
+      __pointer_type
+      operator+=(ptrdiff_t __d) volatile noexcept
+      {
+#if __cplusplus >= 201703L
+	static_assert( is_object<_Tp>::value, "pointer to object type" );
+#endif
+	return _M_b.operator+=(__d);
+      }
+
+      __pointer_type
+      operator-=(ptrdiff_t __d) noexcept
+      {
+#if __cplusplus >= 201703L
+	static_assert( is_object<_Tp>::value, "pointer to object type" );
+#endif
+	return _M_b.operator-=(__d);
+      }
+
+      __pointer_type
+      operator-=(ptrdiff_t __d) volatile noexcept
+      {
+#if __cplusplus >= 201703L
+	static_assert( is_object<_Tp>::value, "pointer to object type" );
+#endif
+	return _M_b.operator-=(__d);
+      }
+
+      bool
+      is_lock_free() const noexcept
+      { return _M_b.is_lock_free(); }
+
+      bool
+      is_lock_free() const volatile noexcept
+      { return _M_b.is_lock_free(); }
+
+#if __cplusplus >= 201703L
+      static constexpr bool is_always_lock_free
+	= ATOMIC_POINTER_LOCK_FREE == 2;
+#endif
+
+      void
+      store(__pointer_type __p,
+	    memory_order __m = memory_order_seq_cst) noexcept
+      { return _M_b.store(__p, __m); }
+
+      void
+      store(__pointer_type __p,
+	    memory_order __m = memory_order_seq_cst) volatile noexcept
+      { return _M_b.store(__p, __m); }
+
+      __pointer_type
+      load(memory_order __m = memory_order_seq_cst) const noexcept
+      { return _M_b.load(__m); }
+
+      __pointer_type
+      load(memory_order __m = memory_order_seq_cst) const volatile noexcept
+      { return _M_b.load(__m); }
+
+      __pointer_type
+      exchange(__pointer_type __p,
+	       memory_order __m = memory_order_seq_cst) noexcept
+      { return _M_b.exchange(__p, __m); }
+
+      __pointer_type
+      exchange(__pointer_type __p,
+	       memory_order __m = memory_order_seq_cst) volatile noexcept
+      { return _M_b.exchange(__p, __m); }
+
+      bool
+      compare_exchange_weak(__pointer_type& __p1, __pointer_type __p2,
+			    memory_order __m1, memory_order __m2) noexcept
+      { return _M_b.compare_exchange_weak(__p1, __p2, __m1, __m2); }
+
+      bool
+      compare_exchange_weak(__pointer_type& __p1, __pointer_type __p2,
+			    memory_order __m1,
+			    memory_order __m2) volatile noexcept
+      { return _M_b.compare_exchange_weak(__p1, __p2, __m1, __m2); }
+
+      bool
+      compare_exchange_weak(__pointer_type& __p1, __pointer_type __p2,
+			    memory_order __m = memory_order_seq_cst) noexcept
+      {
+	return compare_exchange_weak(__p1, __p2, __m,
+				     __cmpexch_failure_order(__m));
+      }
+
+      bool
+      compare_exchange_weak(__pointer_type& __p1, __pointer_type __p2,
+		    memory_order __m = memory_order_seq_cst) volatile noexcept
+      {
+	return compare_exchange_weak(__p1, __p2, __m,
+				     __cmpexch_failure_order(__m));
+      }
+
+      bool
+      compare_exchange_strong(__pointer_type& __p1, __pointer_type __p2,
+			      memory_order __m1, memory_order __m2) noexcept
+      { return _M_b.compare_exchange_strong(__p1, __p2, __m1, __m2); }
+
+      bool
+      compare_exchange_strong(__pointer_type& __p1, __pointer_type __p2,
+			      memory_order __m1,
+			      memory_order __m2) volatile noexcept
+      { return _M_b.compare_exchange_strong(__p1, __p2, __m1, __m2); }
+
+      bool
+      compare_exchange_strong(__pointer_type& __p1, __pointer_type __p2,
+			      memory_order __m = memory_order_seq_cst) noexcept
+      {
+	return _M_b.compare_exchange_strong(__p1, __p2, __m,
+					    __cmpexch_failure_order(__m));
+      }
+
+      bool
+      compare_exchange_strong(__pointer_type& __p1, __pointer_type __p2,
+		    memory_order __m = memory_order_seq_cst) volatile noexcept
+      {
+	return _M_b.compare_exchange_strong(__p1, __p2, __m,
+					    __cmpexch_failure_order(__m));
+      }
+
+#if __cpp_lib_atomic_wait
+    void
+    wait(__pointer_type __old, memory_order __m = memory_order_seq_cst) const noexcept
+    { _M_b.wait(__old, __m); }
+
+    // TODO add const volatile overload
+
+    void
+    notify_one() noexcept
+    { _M_b.notify_one(); }
+
+    void
+    notify_all() noexcept
+    { _M_b.notify_all(); }
+#endif // __cpp_lib_atomic_wait
+
+      __pointer_type
+      fetch_add(ptrdiff_t __d,
+		memory_order __m = memory_order_seq_cst) noexcept
+      {
+#if __cplusplus >= 201703L
+	static_assert( is_object<_Tp>::value, "pointer to object type" );
+#endif
+	return _M_b.fetch_add(__d, __m);
+      }
+
+      __pointer_type
+      fetch_add(ptrdiff_t __d,
+		memory_order __m = memory_order_seq_cst) volatile noexcept
+      {
+#if __cplusplus >= 201703L
+	static_assert( is_object<_Tp>::value, "pointer to object type" );
+#endif
+	return _M_b.fetch_add(__d, __m);
+      }
+
+      __pointer_type
+      fetch_sub(ptrdiff_t __d,
+		memory_order __m = memory_order_seq_cst) noexcept
+      {
+#if __cplusplus >= 201703L
+	static_assert( is_object<_Tp>::value, "pointer to object type" );
+#endif
+	return _M_b.fetch_sub(__d, __m);
+      }
+
+      __pointer_type
+      fetch_sub(ptrdiff_t __d,
+		memory_order __m = memory_order_seq_cst) volatile noexcept
+      {
+#if __cplusplus >= 201703L
+	static_assert( is_object<_Tp>::value, "pointer to object type" );
+#endif
+	return _M_b.fetch_sub(__d, __m);
+      }
+    };
+
+
+  /// Explicit specialization for char.
+  template<>
+    struct atomic<char> : __atomic_base<char>
+    {
+      typedef char 			__integral_type;
+      typedef __atomic_base<char> 	__base_type;
+
+      atomic() noexcept = default;
+      ~atomic() noexcept = default;
+      atomic(const atomic&) = delete;
+      atomic& operator=(const atomic&) = delete;
+      atomic& operator=(const atomic&) volatile = delete;
+
+      constexpr atomic(__integral_type __i) noexcept : __base_type(__i) { }
+
+      using __base_type::operator __integral_type;
+      using __base_type::operator=;
+
+#if __cplusplus >= 201703L
+      static constexpr bool is_always_lock_free = ATOMIC_CHAR_LOCK_FREE == 2;
+#endif
+    };
+
+  /// Explicit specialization for signed char.
+  template<>
+    struct atomic<signed char> : __atomic_base<signed char>
+    {
+      typedef signed char 		__integral_type;
+      typedef __atomic_base<signed char> 	__base_type;
+
+      atomic() noexcept= default;
+      ~atomic() noexcept = default;
+      atomic(const atomic&) = delete;
+      atomic& operator=(const atomic&) = delete;
+      atomic& operator=(const atomic&) volatile = delete;
+
+      constexpr atomic(__integral_type __i) noexcept : __base_type(__i) { }
+
+      using __base_type::operator __integral_type;
+      using __base_type::operator=;
+
+#if __cplusplus >= 201703L
+      static constexpr bool is_always_lock_free = ATOMIC_CHAR_LOCK_FREE == 2;
+#endif
+    };
+
+  /// Explicit specialization for unsigned char.
+  template<>
+    struct atomic<unsigned char> : __atomic_base<unsigned char>
+    {
+      typedef unsigned char 		__integral_type;
+      typedef __atomic_base<unsigned char> 	__base_type;
+
+      atomic() noexcept= default;
+      ~atomic() noexcept = default;
+      atomic(const atomic&) = delete;
+      atomic& operator=(const atomic&) = delete;
+      atomic& operator=(const atomic&) volatile = delete;
+
+      constexpr atomic(__integral_type __i) noexcept : __base_type(__i) { }
+
+      using __base_type::operator __integral_type;
+      using __base_type::operator=;
+
+#if __cplusplus >= 201703L
+      static constexpr bool is_always_lock_free = ATOMIC_CHAR_LOCK_FREE == 2;
+#endif
+    };
+
+  /// Explicit specialization for short.
+  template<>
+    struct atomic<short> : __atomic_base<short>
+    {
+      typedef short 			__integral_type;
+      typedef __atomic_base<short> 		__base_type;
+
+      atomic() noexcept = default;
+      ~atomic() noexcept = default;
+      atomic(const atomic&) = delete;
+      atomic& operator=(const atomic&) = delete;
+      atomic& operator=(const atomic&) volatile = delete;
+
+      constexpr atomic(__integral_type __i) noexcept : __base_type(__i) { }
+
+      using __base_type::operator __integral_type;
+      using __base_type::operator=;
+
+#if __cplusplus >= 201703L
+      static constexpr bool is_always_lock_free = ATOMIC_SHORT_LOCK_FREE == 2;
+#endif
+    };
+
+  /// Explicit specialization for unsigned short.
+  template<>
+    struct atomic<unsigned short> : __atomic_base<unsigned short>
+    {
+      typedef unsigned short 	      	__integral_type;
+      typedef __atomic_base<unsigned short> 		__base_type;
+
+      atomic() noexcept = default;
+      ~atomic() noexcept = default;
+      atomic(const atomic&) = delete;
+      atomic& operator=(const atomic&) = delete;
+      atomic& operator=(const atomic&) volatile = delete;
+
+      constexpr atomic(__integral_type __i) noexcept : __base_type(__i) { }
+
+      using __base_type::operator __integral_type;
+      using __base_type::operator=;
+
+#if __cplusplus >= 201703L
+      static constexpr bool is_always_lock_free = ATOMIC_SHORT_LOCK_FREE == 2;
+#endif
+    };
+
+  /// Explicit specialization for int.
+  template<>
+    struct atomic<int> : __atomic_base<int>
+    {
+      typedef int 			__integral_type;
+      typedef __atomic_base<int> 		__base_type;
+
+      atomic() noexcept = default;
+      ~atomic() noexcept = default;
+      atomic(const atomic&) = delete;
+      atomic& operator=(const atomic&) = delete;
+      atomic& operator=(const atomic&) volatile = delete;
+
+      constexpr atomic(__integral_type __i) noexcept : __base_type(__i) { }
+
+      using __base_type::operator __integral_type;
+      using __base_type::operator=;
+
+#if __cplusplus >= 201703L
+      static constexpr bool is_always_lock_free = ATOMIC_INT_LOCK_FREE == 2;
+#endif
+    };
+
+  /// Explicit specialization for unsigned int.
+  template<>
+    struct atomic<unsigned int> : __atomic_base<unsigned int>
+    {
+      typedef unsigned int		__integral_type;
+      typedef __atomic_base<unsigned int> 	__base_type;
+
+      atomic() noexcept = default;
+      ~atomic() noexcept = default;
+      atomic(const atomic&) = delete;
+      atomic& operator=(const atomic&) = delete;
+      atomic& operator=(const atomic&) volatile = delete;
+
+      constexpr atomic(__integral_type __i) noexcept : __base_type(__i) { }
+
+      using __base_type::operator __integral_type;
+      using __base_type::operator=;
+
+#if __cplusplus >= 201703L
+      static constexpr bool is_always_lock_free = ATOMIC_INT_LOCK_FREE == 2;
+#endif
+    };
+
+  /// Explicit specialization for long.
+  template<>
+    struct atomic<long> : __atomic_base<long>
+    {
+      typedef long 			__integral_type;
+      typedef __atomic_base<long> 	__base_type;
+
+      atomic() noexcept = default;
+      ~atomic() noexcept = default;
+      atomic(const atomic&) = delete;
+      atomic& operator=(const atomic&) = delete;
+      atomic& operator=(const atomic&) volatile = delete;
+
+      constexpr atomic(__integral_type __i) noexcept : __base_type(__i) { }
+
+      using __base_type::operator __integral_type;
+      using __base_type::operator=;
+
+#if __cplusplus >= 201703L
+      static constexpr bool is_always_lock_free = ATOMIC_LONG_LOCK_FREE == 2;
+#endif
+    };
+
+  /// Explicit specialization for unsigned long.
+  template<>
+    struct atomic<unsigned long> : __atomic_base<unsigned long>
+    {
+      typedef unsigned long 		__integral_type;
+      typedef __atomic_base<unsigned long> 	__base_type;
+
+      atomic() noexcept = default;
+      ~atomic() noexcept = default;
+      atomic(const atomic&) = delete;
+      atomic& operator=(const atomic&) = delete;
+      atomic& operator=(const atomic&) volatile = delete;
+
+      constexpr atomic(__integral_type __i) noexcept : __base_type(__i) { }
+
+      using __base_type::operator __integral_type;
+      using __base_type::operator=;
+
+#if __cplusplus >= 201703L
+      static constexpr bool is_always_lock_free = ATOMIC_LONG_LOCK_FREE == 2;
+#endif
+    };
+
+  /// Explicit specialization for long long.
+  template<>
+    struct atomic<long long> : __atomic_base<long long>
+    {
+      typedef long long 		__integral_type;
+      typedef __atomic_base<long long> 		__base_type;
+
+      atomic() noexcept = default;
+      ~atomic() noexcept = default;
+      atomic(const atomic&) = delete;
+      atomic& operator=(const atomic&) = delete;
+      atomic& operator=(const atomic&) volatile = delete;
+
+      constexpr atomic(__integral_type __i) noexcept : __base_type(__i) { }
+
+      using __base_type::operator __integral_type;
+      using __base_type::operator=;
+
+#if __cplusplus >= 201703L
+      static constexpr bool is_always_lock_free = ATOMIC_LLONG_LOCK_FREE == 2;
+#endif
+    };
+
+  /// Explicit specialization for unsigned long long.
+  template<>
+    struct atomic<unsigned long long> : __atomic_base<unsigned long long>
+    {
+      typedef unsigned long long       	__integral_type;
+      typedef __atomic_base<unsigned long long> 	__base_type;
+
+      atomic() noexcept = default;
+      ~atomic() noexcept = default;
+      atomic(const atomic&) = delete;
+      atomic& operator=(const atomic&) = delete;
+      atomic& operator=(const atomic&) volatile = delete;
+
+      constexpr atomic(__integral_type __i) noexcept : __base_type(__i) { }
+
+      using __base_type::operator __integral_type;
+      using __base_type::operator=;
+
+#if __cplusplus >= 201703L
+      static constexpr bool is_always_lock_free = ATOMIC_LLONG_LOCK_FREE == 2;
+#endif
+    };
+
+  /// Explicit specialization for wchar_t.
+  template<>
+    struct atomic<wchar_t> : __atomic_base<wchar_t>
+    {
+      typedef wchar_t 			__integral_type;
+      typedef __atomic_base<wchar_t> 	__base_type;
+
+      atomic() noexcept = default;
+      ~atomic() noexcept = default;
+      atomic(const atomic&) = delete;
+      atomic& operator=(const atomic&) = delete;
+      atomic& operator=(const atomic&) volatile = delete;
+
+      constexpr atomic(__integral_type __i) noexcept : __base_type(__i) { }
+
+      using __base_type::operator __integral_type;
+      using __base_type::operator=;
+
+#if __cplusplus >= 201703L
+      static constexpr bool is_always_lock_free = ATOMIC_WCHAR_T_LOCK_FREE == 2;
+#endif
+    };
+
+#ifdef _GLIBCXX_USE_CHAR8_T
+  /// Explicit specialization for char8_t.
+  template<>
+    struct atomic<char8_t> : __atomic_base<char8_t>
+    {
+      typedef char8_t 			__integral_type;
+      typedef __atomic_base<char8_t> 	__base_type;
+
+      atomic() noexcept = default;
+      ~atomic() noexcept = default;
+      atomic(const atomic&) = delete;
+      atomic& operator=(const atomic&) = delete;
+      atomic& operator=(const atomic&) volatile = delete;
+
+      constexpr atomic(__integral_type __i) noexcept : __base_type(__i) { }
+
+      using __base_type::operator __integral_type;
+      using __base_type::operator=;
+
+#if __cplusplus > 201402L
+      static constexpr bool is_always_lock_free
+	= ATOMIC_CHAR8_T_LOCK_FREE == 2;
+#endif
+    };
+#endif
+
+  /// Explicit specialization for char16_t.
+  template<>
+    struct atomic<char16_t> : __atomic_base<char16_t>
+    {
+      typedef char16_t 			__integral_type;
+      typedef __atomic_base<char16_t> 	__base_type;
+
+      atomic() noexcept = default;
+      ~atomic() noexcept = default;
+      atomic(const atomic&) = delete;
+      atomic& operator=(const atomic&) = delete;
+      atomic& operator=(const atomic&) volatile = delete;
+
+      constexpr atomic(__integral_type __i) noexcept : __base_type(__i) { }
+
+      using __base_type::operator __integral_type;
+      using __base_type::operator=;
+
+#if __cplusplus >= 201703L
+      static constexpr bool is_always_lock_free
+	= ATOMIC_CHAR16_T_LOCK_FREE == 2;
+#endif
+    };
+
+  /// Explicit specialization for char32_t.
+  template<>
+    struct atomic<char32_t> : __atomic_base<char32_t>
+    {
+      typedef char32_t 			__integral_type;
+      typedef __atomic_base<char32_t> 	__base_type;
+
+      atomic() noexcept = default;
+      ~atomic() noexcept = default;
+      atomic(const atomic&) = delete;
+      atomic& operator=(const atomic&) = delete;
+      atomic& operator=(const atomic&) volatile = delete;
+
+      constexpr atomic(__integral_type __i) noexcept : __base_type(__i) { }
+
+      using __base_type::operator __integral_type;
+      using __base_type::operator=;
+
+#if __cplusplus >= 201703L
+      static constexpr bool is_always_lock_free
+	= ATOMIC_CHAR32_T_LOCK_FREE == 2;
+#endif
+    };
+
+
+  /// atomic_bool
+  typedef atomic<bool>			atomic_bool;
+
+  /// atomic_char
+  typedef atomic<char>			atomic_char;
+
+  /// atomic_schar
+  typedef atomic<signed char>		atomic_schar;
+
+  /// atomic_uchar
+  typedef atomic<unsigned char>		atomic_uchar;
+
+  /// atomic_short
+  typedef atomic<short>			atomic_short;
+
+  /// atomic_ushort
+  typedef atomic<unsigned short>	atomic_ushort;
+
+  /// atomic_int
+  typedef atomic<int>			atomic_int;
+
+  /// atomic_uint
+  typedef atomic<unsigned int>		atomic_uint;
+
+  /// atomic_long
+  typedef atomic<long>			atomic_long;
+
+  /// atomic_ulong
+  typedef atomic<unsigned long>		atomic_ulong;
+
+  /// atomic_llong
+  typedef atomic<long long>		atomic_llong;
+
+  /// atomic_ullong
+  typedef atomic<unsigned long long>	atomic_ullong;
+
+  /// atomic_wchar_t
+  typedef atomic<wchar_t>		atomic_wchar_t;
+
+#ifdef _GLIBCXX_USE_CHAR8_T
+  /// atomic_char8_t
+  typedef atomic<char8_t>		atomic_char8_t;
+#endif
+
+  /// atomic_char16_t
+  typedef atomic<char16_t>		atomic_char16_t;
+
+  /// atomic_char32_t
+  typedef atomic<char32_t>		atomic_char32_t;
+
+#ifdef _GLIBCXX_USE_C99_STDINT_TR1
+  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+  // 2441. Exact-width atomic typedefs should be provided
+
+  /// atomic_int8_t
+  typedef atomic<int8_t>		atomic_int8_t;
+
+  /// atomic_uint8_t
+  typedef atomic<uint8_t>		atomic_uint8_t;
+
+  /// atomic_int16_t
+  typedef atomic<int16_t>		atomic_int16_t;
+
+  /// atomic_uint16_t
+  typedef atomic<uint16_t>		atomic_uint16_t;
+
+  /// atomic_int32_t
+  typedef atomic<int32_t>		atomic_int32_t;
+
+  /// atomic_uint32_t
+  typedef atomic<uint32_t>		atomic_uint32_t;
+
+  /// atomic_int64_t
+  typedef atomic<int64_t>		atomic_int64_t;
+
+  /// atomic_uint64_t
+  typedef atomic<uint64_t>		atomic_uint64_t;
+
+
+  /// atomic_int_least8_t
+  typedef atomic<int_least8_t>		atomic_int_least8_t;
+
+  /// atomic_uint_least8_t
+  typedef atomic<uint_least8_t>		atomic_uint_least8_t;
+
+  /// atomic_int_least16_t
+  typedef atomic<int_least16_t>		atomic_int_least16_t;
+
+  /// atomic_uint_least16_t
+  typedef atomic<uint_least16_t>	atomic_uint_least16_t;
+
+  /// atomic_int_least32_t
+  typedef atomic<int_least32_t>		atomic_int_least32_t;
+
+  /// atomic_uint_least32_t
+  typedef atomic<uint_least32_t>	atomic_uint_least32_t;
+
+  /// atomic_int_least64_t
+  typedef atomic<int_least64_t>		atomic_int_least64_t;
+
+  /// atomic_uint_least64_t
+  typedef atomic<uint_least64_t>	atomic_uint_least64_t;
+
+
+  /// atomic_int_fast8_t
+  typedef atomic<int_fast8_t>		atomic_int_fast8_t;
+
+  /// atomic_uint_fast8_t
+  typedef atomic<uint_fast8_t>		atomic_uint_fast8_t;
+
+  /// atomic_int_fast16_t
+  typedef atomic<int_fast16_t>		atomic_int_fast16_t;
+
+  /// atomic_uint_fast16_t
+  typedef atomic<uint_fast16_t>		atomic_uint_fast16_t;
+
+  /// atomic_int_fast32_t
+  typedef atomic<int_fast32_t>		atomic_int_fast32_t;
+
+  /// atomic_uint_fast32_t
+  typedef atomic<uint_fast32_t>		atomic_uint_fast32_t;
+
+  /// atomic_int_fast64_t
+  typedef atomic<int_fast64_t>		atomic_int_fast64_t;
+
+  /// atomic_uint_fast64_t
+  typedef atomic<uint_fast64_t>		atomic_uint_fast64_t;
+#endif
+
+
+  /// atomic_intptr_t
+  typedef atomic<intptr_t>		atomic_intptr_t;
+
+  /// atomic_uintptr_t
+  typedef atomic<uintptr_t>		atomic_uintptr_t;
+
+  /// atomic_size_t
+  typedef atomic<size_t>		atomic_size_t;
+
+  /// atomic_ptrdiff_t
+  typedef atomic<ptrdiff_t>		atomic_ptrdiff_t;
+
+#ifdef _GLIBCXX_USE_C99_STDINT_TR1
+  /// atomic_intmax_t
+  typedef atomic<intmax_t>		atomic_intmax_t;
+
+  /// atomic_uintmax_t
+  typedef atomic<uintmax_t>		atomic_uintmax_t;
+#endif
+
+  // Function definitions, atomic_flag operations.
+  inline bool
+  atomic_flag_test_and_set_explicit(atomic_flag* __a,
+				    memory_order __m) noexcept
+  { return __a->test_and_set(__m); }
+
+  inline bool
+  atomic_flag_test_and_set_explicit(volatile atomic_flag* __a,
+				    memory_order __m) noexcept
+  { return __a->test_and_set(__m); }
+
+  inline void
+  atomic_flag_clear_explicit(atomic_flag* __a, memory_order __m) noexcept
+  { __a->clear(__m); }
+
+  inline void
+  atomic_flag_clear_explicit(volatile atomic_flag* __a,
+			     memory_order __m) noexcept
+  { __a->clear(__m); }
+
+  inline bool
+  atomic_flag_test_and_set(atomic_flag* __a) noexcept
+  { return atomic_flag_test_and_set_explicit(__a, memory_order_seq_cst); }
+
+  inline bool
+  atomic_flag_test_and_set(volatile atomic_flag* __a) noexcept
+  { return atomic_flag_test_and_set_explicit(__a, memory_order_seq_cst); }
+
+  inline void
+  atomic_flag_clear(atomic_flag* __a) noexcept
+  { atomic_flag_clear_explicit(__a, memory_order_seq_cst); }
+
+  inline void
+  atomic_flag_clear(volatile atomic_flag* __a) noexcept
+  { atomic_flag_clear_explicit(__a, memory_order_seq_cst); }
+
+  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+  // 3220. P0558 broke conforming C++14 uses of atomic shared_ptr
+  template<typename _Tp>
+    using __atomic_val_t = __type_identity_t<_Tp>;
+  template<typename _Tp>
+    using __atomic_diff_t = typename atomic<_Tp>::difference_type;
+
+  // [atomics.nonmembers] Non-member functions.
+  // Function templates generally applicable to atomic types.
+  template<typename _ITp>
+    inline bool
+    atomic_is_lock_free(const atomic<_ITp>* __a) noexcept
+    { return __a->is_lock_free(); }
+
+  template<typename _ITp>
+    inline bool
+    atomic_is_lock_free(const volatile atomic<_ITp>* __a) noexcept
+    { return __a->is_lock_free(); }
+
+  template<typename _ITp>
+    inline void
+    atomic_init(atomic<_ITp>* __a, __atomic_val_t<_ITp> __i) noexcept
+    { __a->store(__i, memory_order_relaxed); }
+
+  template<typename _ITp>
+    inline void
+    atomic_init(volatile atomic<_ITp>* __a, __atomic_val_t<_ITp> __i) noexcept
+    { __a->store(__i, memory_order_relaxed); }
+
+  template<typename _ITp>
+    inline void
+    atomic_store_explicit(atomic<_ITp>* __a, __atomic_val_t<_ITp> __i,
+			  memory_order __m) noexcept
+    { __a->store(__i, __m); }
+
+  template<typename _ITp>
+    inline void
+    atomic_store_explicit(volatile atomic<_ITp>* __a, __atomic_val_t<_ITp> __i,
+			  memory_order __m) noexcept
+    { __a->store(__i, __m); }
+
+  template<typename _ITp>
+    inline _ITp
+    atomic_load_explicit(const atomic<_ITp>* __a, memory_order __m) noexcept
+    { return __a->load(__m); }
+
+  template<typename _ITp>
+    inline _ITp
+    atomic_load_explicit(const volatile atomic<_ITp>* __a,
+			 memory_order __m) noexcept
+    { return __a->load(__m); }
+
+  template<typename _ITp>
+    inline _ITp
+    atomic_exchange_explicit(atomic<_ITp>* __a, __atomic_val_t<_ITp> __i,
+			     memory_order __m) noexcept
+    { return __a->exchange(__i, __m); }
+
+  template<typename _ITp>
+    inline _ITp
+    atomic_exchange_explicit(volatile atomic<_ITp>* __a,
+			     __atomic_val_t<_ITp> __i,
+			     memory_order __m) noexcept
+    { return __a->exchange(__i, __m); }
+
+  template<typename _ITp>
+    inline bool
+    atomic_compare_exchange_weak_explicit(atomic<_ITp>* __a,
+					  __atomic_val_t<_ITp>* __i1,
+					  __atomic_val_t<_ITp> __i2,
+					  memory_order __m1,
+					  memory_order __m2) noexcept
+    { return __a->compare_exchange_weak(*__i1, __i2, __m1, __m2); }
+
+  template<typename _ITp>
+    inline bool
+    atomic_compare_exchange_weak_explicit(volatile atomic<_ITp>* __a,
+					  __atomic_val_t<_ITp>* __i1,
+					  __atomic_val_t<_ITp> __i2,
+					  memory_order __m1,
+					  memory_order __m2) noexcept
+    { return __a->compare_exchange_weak(*__i1, __i2, __m1, __m2); }
+
+  template<typename _ITp>
+    inline bool
+    atomic_compare_exchange_strong_explicit(atomic<_ITp>* __a,
+					    __atomic_val_t<_ITp>* __i1,
+					    __atomic_val_t<_ITp> __i2,
+					    memory_order __m1,
+					    memory_order __m2) noexcept
+    { return __a->compare_exchange_strong(*__i1, __i2, __m1, __m2); }
+
+  template<typename _ITp>
+    inline bool
+    atomic_compare_exchange_strong_explicit(volatile atomic<_ITp>* __a,
+					    __atomic_val_t<_ITp>* __i1,
+					    __atomic_val_t<_ITp> __i2,
+					    memory_order __m1,
+					    memory_order __m2) noexcept
+    { return __a->compare_exchange_strong(*__i1, __i2, __m1, __m2); }
+
+
+  template<typename _ITp>
+    inline void
+    atomic_store(atomic<_ITp>* __a, __atomic_val_t<_ITp> __i) noexcept
+    { atomic_store_explicit(__a, __i, memory_order_seq_cst); }
+
+  template<typename _ITp>
+    inline void
+    atomic_store(volatile atomic<_ITp>* __a, __atomic_val_t<_ITp> __i) noexcept
+    { atomic_store_explicit(__a, __i, memory_order_seq_cst); }
+
+  template<typename _ITp>
+    inline _ITp
+    atomic_load(const atomic<_ITp>* __a) noexcept
+    { return atomic_load_explicit(__a, memory_order_seq_cst); }
+
+  template<typename _ITp>
+    inline _ITp
+    atomic_load(const volatile atomic<_ITp>* __a) noexcept
+    { return atomic_load_explicit(__a, memory_order_seq_cst); }
+
+  template<typename _ITp>
+    inline _ITp
+    atomic_exchange(atomic<_ITp>* __a, __atomic_val_t<_ITp> __i) noexcept
+    { return atomic_exchange_explicit(__a, __i, memory_order_seq_cst); }
+
+  template<typename _ITp>
+    inline _ITp
+    atomic_exchange(volatile atomic<_ITp>* __a,
+		    __atomic_val_t<_ITp> __i) noexcept
+    { return atomic_exchange_explicit(__a, __i, memory_order_seq_cst); }
+
+  template<typename _ITp>
+    inline bool
+    atomic_compare_exchange_weak(atomic<_ITp>* __a,
+				 __atomic_val_t<_ITp>* __i1,
+				 __atomic_val_t<_ITp> __i2) noexcept
+    {
+      return atomic_compare_exchange_weak_explicit(__a, __i1, __i2,
+						   memory_order_seq_cst,
+						   memory_order_seq_cst);
+    }
+
+  template<typename _ITp>
+    inline bool
+    atomic_compare_exchange_weak(volatile atomic<_ITp>* __a,
+				 __atomic_val_t<_ITp>* __i1,
+				 __atomic_val_t<_ITp> __i2) noexcept
+    {
+      return atomic_compare_exchange_weak_explicit(__a, __i1, __i2,
+						   memory_order_seq_cst,
+						   memory_order_seq_cst);
+    }
+
+  template<typename _ITp>
+    inline bool
+    atomic_compare_exchange_strong(atomic<_ITp>* __a,
+				   __atomic_val_t<_ITp>* __i1,
+				   __atomic_val_t<_ITp> __i2) noexcept
+    {
+      return atomic_compare_exchange_strong_explicit(__a, __i1, __i2,
+						     memory_order_seq_cst,
+						     memory_order_seq_cst);
+    }
+
+  template<typename _ITp>
+    inline bool
+    atomic_compare_exchange_strong(volatile atomic<_ITp>* __a,
+				   __atomic_val_t<_ITp>* __i1,
+				   __atomic_val_t<_ITp> __i2) noexcept
+    {
+      return atomic_compare_exchange_strong_explicit(__a, __i1, __i2,
+						     memory_order_seq_cst,
+						     memory_order_seq_cst);
+    }
+
+
+#if __cpp_lib_atomic_wait
+  template<typename _Tp>
+    inline void
+    atomic_wait(const atomic<_Tp>* __a,
+	        typename std::atomic<_Tp>::value_type __old) noexcept
+    { __a->wait(__old); }
+
+  template<typename _Tp>
+    inline void
+    atomic_wait_explicit(const atomic<_Tp>* __a,
+			 typename std::atomic<_Tp>::value_type __old,
+			 std::memory_order __m) noexcept
+    { __a->wait(__old, __m); }
+
+  template<typename _Tp>
+    inline void
+    atomic_notify_one(atomic<_Tp>* __a) noexcept
+    { __a->notify_one(); }
+
+  template<typename _Tp>
+    inline void
+    atomic_notify_all(atomic<_Tp>* __a) noexcept
+    { __a->notify_all(); }
+#endif // __cpp_lib_atomic_wait
+
+  // Function templates for atomic_integral and atomic_pointer operations only.
+  // Some operations (and, or, xor) are only available for atomic integrals,
+  // which is implemented by taking a parameter of type __atomic_base<_ITp>*.
+
+  template<typename _ITp>
+    inline _ITp
+    atomic_fetch_add_explicit(atomic<_ITp>* __a,
+			      __atomic_diff_t<_ITp> __i,
+			      memory_order __m) noexcept
+    { return __a->fetch_add(__i, __m); }
+
+  template<typename _ITp>
+    inline _ITp
+    atomic_fetch_add_explicit(volatile atomic<_ITp>* __a,
+			      __atomic_diff_t<_ITp> __i,
+			      memory_order __m) noexcept
+    { return __a->fetch_add(__i, __m); }
+
+  template<typename _ITp>
+    inline _ITp
+    atomic_fetch_sub_explicit(atomic<_ITp>* __a,
+			      __atomic_diff_t<_ITp> __i,
+			      memory_order __m) noexcept
+    { return __a->fetch_sub(__i, __m); }
+
+  template<typename _ITp>
+    inline _ITp
+    atomic_fetch_sub_explicit(volatile atomic<_ITp>* __a,
+			      __atomic_diff_t<_ITp> __i,
+			      memory_order __m) noexcept
+    { return __a->fetch_sub(__i, __m); }
+
+  template<typename _ITp>
+    inline _ITp
+    atomic_fetch_and_explicit(__atomic_base<_ITp>* __a,
+			      __atomic_val_t<_ITp> __i,
+			      memory_order __m) noexcept
+    { return __a->fetch_and(__i, __m); }
+
+  template<typename _ITp>
+    inline _ITp
+    atomic_fetch_and_explicit(volatile __atomic_base<_ITp>* __a,
+			      __atomic_val_t<_ITp> __i,
+			      memory_order __m) noexcept
+    { return __a->fetch_and(__i, __m); }
+
+  template<typename _ITp>
+    inline _ITp
+    atomic_fetch_or_explicit(__atomic_base<_ITp>* __a,
+			     __atomic_val_t<_ITp> __i,
+			     memory_order __m) noexcept
+    { return __a->fetch_or(__i, __m); }
+
+  template<typename _ITp>
+    inline _ITp
+    atomic_fetch_or_explicit(volatile __atomic_base<_ITp>* __a,
+			     __atomic_val_t<_ITp> __i,
+			     memory_order __m) noexcept
+    { return __a->fetch_or(__i, __m); }
+
+  template<typename _ITp>
+    inline _ITp
+    atomic_fetch_xor_explicit(__atomic_base<_ITp>* __a,
+			      __atomic_val_t<_ITp> __i,
+			      memory_order __m) noexcept
+    { return __a->fetch_xor(__i, __m); }
+
+  template<typename _ITp>
+    inline _ITp
+    atomic_fetch_xor_explicit(volatile __atomic_base<_ITp>* __a,
+			      __atomic_val_t<_ITp> __i,
+			      memory_order __m) noexcept
+    { return __a->fetch_xor(__i, __m); }
+
+  template<typename _ITp>
+    inline _ITp
+    atomic_fetch_add(atomic<_ITp>* __a,
+		     __atomic_diff_t<_ITp> __i) noexcept
+    { return atomic_fetch_add_explicit(__a, __i, memory_order_seq_cst); }
+
+  template<typename _ITp>
+    inline _ITp
+    atomic_fetch_add(volatile atomic<_ITp>* __a,
+		     __atomic_diff_t<_ITp> __i) noexcept
+    { return atomic_fetch_add_explicit(__a, __i, memory_order_seq_cst); }
+
+  template<typename _ITp>
+    inline _ITp
+    atomic_fetch_sub(atomic<_ITp>* __a,
+		     __atomic_diff_t<_ITp> __i) noexcept
+    { return atomic_fetch_sub_explicit(__a, __i, memory_order_seq_cst); }
+
+  template<typename _ITp>
+    inline _ITp
+    atomic_fetch_sub(volatile atomic<_ITp>* __a,
+		     __atomic_diff_t<_ITp> __i) noexcept
+    { return atomic_fetch_sub_explicit(__a, __i, memory_order_seq_cst); }
+
+  template<typename _ITp>
+    inline _ITp
+    atomic_fetch_and(__atomic_base<_ITp>* __a,
+		     __atomic_val_t<_ITp> __i) noexcept
+    { return atomic_fetch_and_explicit(__a, __i, memory_order_seq_cst); }
+
+  template<typename _ITp>
+    inline _ITp
+    atomic_fetch_and(volatile __atomic_base<_ITp>* __a,
+		     __atomic_val_t<_ITp> __i) noexcept
+    { return atomic_fetch_and_explicit(__a, __i, memory_order_seq_cst); }
+
+  template<typename _ITp>
+    inline _ITp
+    atomic_fetch_or(__atomic_base<_ITp>* __a,
+		    __atomic_val_t<_ITp> __i) noexcept
+    { return atomic_fetch_or_explicit(__a, __i, memory_order_seq_cst); }
+
+  template<typename _ITp>
+    inline _ITp
+    atomic_fetch_or(volatile __atomic_base<_ITp>* __a,
+		    __atomic_val_t<_ITp> __i) noexcept
+    { return atomic_fetch_or_explicit(__a, __i, memory_order_seq_cst); }
+
+  template<typename _ITp>
+    inline _ITp
+    atomic_fetch_xor(__atomic_base<_ITp>* __a,
+		     __atomic_val_t<_ITp> __i) noexcept
+    { return atomic_fetch_xor_explicit(__a, __i, memory_order_seq_cst); }
+
+  template<typename _ITp>
+    inline _ITp
+    atomic_fetch_xor(volatile __atomic_base<_ITp>* __a,
+		     __atomic_val_t<_ITp> __i) noexcept
+    { return atomic_fetch_xor_explicit(__a, __i, memory_order_seq_cst); }
+
+#if __cplusplus > 201703L
+#define __cpp_lib_atomic_float 201711L
+  template<>
+    struct atomic<float> : __atomic_float<float>
+    {
+      atomic() noexcept = default;
+
+      constexpr
+      atomic(float __fp) noexcept : __atomic_float<float>(__fp)
+      { }
+
+      atomic& operator=(const atomic&) volatile = delete;
+      atomic& operator=(const atomic&) = delete;
+
+      using __atomic_float<float>::operator=;
+    };
+
+  template<>
+    struct atomic<double> : __atomic_float<double>
+    {
+      atomic() noexcept = default;
+
+      constexpr
+      atomic(double __fp) noexcept : __atomic_float<double>(__fp)
+      { }
+
+      atomic& operator=(const atomic&) volatile = delete;
+      atomic& operator=(const atomic&) = delete;
+
+      using __atomic_float<double>::operator=;
+    };
+
+  template<>
+    struct atomic<long double> : __atomic_float<long double>
+    {
+      atomic() noexcept = default;
+
+      constexpr
+      atomic(long double __fp) noexcept : __atomic_float<long double>(__fp)
+      { }
+
+      atomic& operator=(const atomic&) volatile = delete;
+      atomic& operator=(const atomic&) = delete;
+
+      using __atomic_float<long double>::operator=;
+    };
+
+#define __cpp_lib_atomic_ref 201806L
+
+  /// Class template to provide atomic operations on a non-atomic variable.
+  template<typename _Tp>
+    struct atomic_ref : __atomic_ref<_Tp>
+    {
+      explicit
+      atomic_ref(_Tp& __t) noexcept : __atomic_ref<_Tp>(__t)
+      { }
+
+      atomic_ref& operator=(const atomic_ref&) = delete;
+
+      atomic_ref(const atomic_ref&) = default;
+
+      using __atomic_ref<_Tp>::operator=;
+    };
+
+#endif // C++2a
+
+  /// @} group atomics
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif // C++11
+
+#endif // _GLIBCXX_ATOMIC
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@@ -0,0 +1,337 @@
+// auto_ptr implementation -*- C++ -*-
+
+// Copyright (C) 2007-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file backward/auto_ptr.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{memory}
+ */
+
+#ifndef _BACKWARD_AUTO_PTR_H
+#define _BACKWARD_AUTO_PTR_H 1
+
+#include <bits/c++config.h>
+#include <debug/debug.h>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /**
+   *  A wrapper class to provide auto_ptr with reference semantics.
+   *  For example, an auto_ptr can be assigned (or constructed from)
+   *  the result of a function which returns an auto_ptr by value.
+   *
+   *  All the auto_ptr_ref stuff should happen behind the scenes.
+   */
+  template<typename _Tp1>
+    struct auto_ptr_ref
+    {
+      _Tp1* _M_ptr;
+      
+      explicit
+      auto_ptr_ref(_Tp1* __p): _M_ptr(__p) { }
+    } _GLIBCXX11_DEPRECATED;
+
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+
+  /**
+   *  @brief  A simple smart pointer providing strict ownership semantics.
+   *
+   *  The Standard says:
+   *  <pre>
+   *  An @c auto_ptr owns the object it holds a pointer to.  Copying
+   *  an @c auto_ptr copies the pointer and transfers ownership to the
+   *  destination.  If more than one @c auto_ptr owns the same object
+   *  at the same time the behavior of the program is undefined.
+   *
+   *  The uses of @c auto_ptr include providing temporary
+   *  exception-safety for dynamically allocated memory, passing
+   *  ownership of dynamically allocated memory to a function, and
+   *  returning dynamically allocated memory from a function.  @c
+   *  auto_ptr does not meet the CopyConstructible and Assignable
+   *  requirements for Standard Library <a
+   *  href="tables.html#65">container</a> elements and thus
+   *  instantiating a Standard Library container with an @c auto_ptr
+   *  results in undefined behavior.
+   *  </pre>
+   *  Quoted from [20.4.5]/3.
+   *
+   *  Good examples of what can and cannot be done with auto_ptr can
+   *  be found in the libstdc++ testsuite.
+   *
+   *  _GLIBCXX_RESOLVE_LIB_DEFECTS
+   *  127.  auto_ptr<> conversion issues
+   *  These resolutions have all been incorporated.
+   */
+  template<typename _Tp>
+    class auto_ptr
+    {
+    private:
+      _Tp* _M_ptr;
+      
+    public:
+      /// The pointed-to type.
+      typedef _Tp element_type;
+      
+      /**
+       *  @brief  An %auto_ptr is usually constructed from a raw pointer.
+       *  @param  __p  A pointer (defaults to NULL).
+       *
+       *  This object now @e owns the object pointed to by @a __p.
+       */
+      explicit
+      auto_ptr(element_type* __p = 0) throw() : _M_ptr(__p) { }
+
+      /**
+       *  @brief  An %auto_ptr can be constructed from another %auto_ptr.
+       *  @param  __a  Another %auto_ptr of the same type.
+       *
+       *  This object now @e owns the object previously owned by @a __a,
+       *  which has given up ownership.
+       */
+      auto_ptr(auto_ptr& __a) throw() : _M_ptr(__a.release()) { }
+
+      /**
+       *  @brief  An %auto_ptr can be constructed from another %auto_ptr.
+       *  @param  __a  Another %auto_ptr of a different but related type.
+       *
+       *  A pointer-to-Tp1 must be convertible to a
+       *  pointer-to-Tp/element_type.
+       *
+       *  This object now @e owns the object previously owned by @a __a,
+       *  which has given up ownership.
+       */
+      template<typename _Tp1>
+        auto_ptr(auto_ptr<_Tp1>& __a) throw() : _M_ptr(__a.release()) { }
+
+      /**
+       *  @brief  %auto_ptr assignment operator.
+       *  @param  __a  Another %auto_ptr of the same type.
+       *
+       *  This object now @e owns the object previously owned by @a __a,
+       *  which has given up ownership.  The object that this one @e
+       *  used to own and track has been deleted.
+       */
+      auto_ptr&
+      operator=(auto_ptr& __a) throw()
+      {
+	reset(__a.release());
+	return *this;
+      }
+
+      /**
+       *  @brief  %auto_ptr assignment operator.
+       *  @param  __a  Another %auto_ptr of a different but related type.
+       *
+       *  A pointer-to-Tp1 must be convertible to a pointer-to-Tp/element_type.
+       *
+       *  This object now @e owns the object previously owned by @a __a,
+       *  which has given up ownership.  The object that this one @e
+       *  used to own and track has been deleted.
+       */
+      template<typename _Tp1>
+        auto_ptr&
+        operator=(auto_ptr<_Tp1>& __a) throw()
+        {
+	  reset(__a.release());
+	  return *this;
+	}
+
+      /**
+       *  When the %auto_ptr goes out of scope, the object it owns is
+       *  deleted.  If it no longer owns anything (i.e., @c get() is
+       *  @c NULL), then this has no effect.
+       *
+       *  The C++ standard says there is supposed to be an empty throw
+       *  specification here, but omitting it is standard conforming.  Its
+       *  presence can be detected only if _Tp::~_Tp() throws, but this is
+       *  prohibited.  [17.4.3.6]/2
+       */
+      ~auto_ptr() { delete _M_ptr; }
+      
+      /**
+       *  @brief  Smart pointer dereferencing.
+       *
+       *  If this %auto_ptr no longer owns anything, then this
+       *  operation will crash.  (For a smart pointer, <em>no longer owns
+       *  anything</em> is the same as being a null pointer, and you know
+       *  what happens when you dereference one of those...)
+       */
+      element_type&
+      operator*() const throw() 
+      {
+	__glibcxx_assert(_M_ptr != 0);
+	return *_M_ptr; 
+      }
+      
+      /**
+       *  @brief  Smart pointer dereferencing.
+       *
+       *  This returns the pointer itself, which the language then will
+       *  automatically cause to be dereferenced.
+       */
+      element_type*
+      operator->() const throw() 
+      {
+	__glibcxx_assert(_M_ptr != 0);
+	return _M_ptr; 
+      }
+      
+      /**
+       *  @brief  Bypassing the smart pointer.
+       *  @return  The raw pointer being managed.
+       *
+       *  You can get a copy of the pointer that this object owns, for
+       *  situations such as passing to a function which only accepts
+       *  a raw pointer.
+       *
+       *  @note  This %auto_ptr still owns the memory.
+       */
+      element_type*
+      get() const throw() { return _M_ptr; }
+      
+      /**
+       *  @brief  Bypassing the smart pointer.
+       *  @return  The raw pointer being managed.
+       *
+       *  You can get a copy of the pointer that this object owns, for
+       *  situations such as passing to a function which only accepts
+       *  a raw pointer.
+       *
+       *  @note  This %auto_ptr no longer owns the memory.  When this object
+       *  goes out of scope, nothing will happen.
+       */
+      element_type*
+      release() throw()
+      {
+	element_type* __tmp = _M_ptr;
+	_M_ptr = 0;
+	return __tmp;
+      }
+      
+      /**
+       *  @brief  Forcibly deletes the managed object.
+       *  @param  __p  A pointer (defaults to NULL).
+       *
+       *  This object now @e owns the object pointed to by @a __p.  The
+       *  previous object has been deleted.
+       */
+      void
+      reset(element_type* __p = 0) throw()
+      {
+	if (__p != _M_ptr)
+	  {
+	    delete _M_ptr;
+	    _M_ptr = __p;
+	  }
+      }
+      
+      /** 
+       *  @brief  Automatic conversions
+       *
+       *  These operations are supposed to convert an %auto_ptr into and from
+       *  an auto_ptr_ref automatically as needed.  This would allow
+       *  constructs such as
+       *  @code
+       *    auto_ptr<Derived>  func_returning_auto_ptr(.....);
+       *    ...
+       *    auto_ptr<Base> ptr = func_returning_auto_ptr(.....);
+       *  @endcode
+       *
+       *  But it doesn't work, and won't be fixed. For further details see
+       *  http://cplusplus.github.io/LWG/lwg-closed.html#463
+       */
+      auto_ptr(auto_ptr_ref<element_type> __ref) throw()
+      : _M_ptr(__ref._M_ptr) { }
+      
+      auto_ptr&
+      operator=(auto_ptr_ref<element_type> __ref) throw()
+      {
+	if (__ref._M_ptr != this->get())
+	  {
+	    delete _M_ptr;
+	    _M_ptr = __ref._M_ptr;
+	  }
+	return *this;
+      }
+      
+      template<typename _Tp1>
+        operator auto_ptr_ref<_Tp1>() throw()
+        { return auto_ptr_ref<_Tp1>(this->release()); }
+
+      template<typename _Tp1>
+        operator auto_ptr<_Tp1>() throw()
+        { return auto_ptr<_Tp1>(this->release()); }
+    } _GLIBCXX11_DEPRECATED_SUGGEST("std::unique_ptr");
+
+  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+  // 541. shared_ptr template assignment and void
+  template<>
+    class auto_ptr<void>
+    {
+    public:
+      typedef void element_type;
+    } _GLIBCXX11_DEPRECATED;
+
+#if __cplusplus >= 201103L
+  template<_Lock_policy _Lp>
+  template<typename _Tp>
+    inline
+    __shared_count<_Lp>::__shared_count(std::auto_ptr<_Tp>&& __r)
+    : _M_pi(new _Sp_counted_ptr<_Tp*, _Lp>(__r.get()))
+    { __r.release(); }
+
+  template<typename _Tp, _Lock_policy _Lp>
+  template<typename _Tp1, typename>
+    inline
+    __shared_ptr<_Tp, _Lp>::__shared_ptr(std::auto_ptr<_Tp1>&& __r)
+    : _M_ptr(__r.get()), _M_refcount()
+    {
+      __glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>)
+      static_assert( sizeof(_Tp1) > 0, "incomplete type" );
+      _Tp1* __tmp = __r.get();
+      _M_refcount = __shared_count<_Lp>(std::move(__r));
+      _M_enable_shared_from_this_with(__tmp);
+    }
+
+  template<typename _Tp>
+  template<typename _Tp1, typename>
+    inline
+    shared_ptr<_Tp>::shared_ptr(std::auto_ptr<_Tp1>&& __r)
+    : __shared_ptr<_Tp>(std::move(__r)) { }
+
+  template<typename _Tp, typename _Dp>
+  template<typename _Up, typename>
+    inline
+    unique_ptr<_Tp, _Dp>::unique_ptr(auto_ptr<_Up>&& __u) noexcept
+    : _M_t(__u.release(), deleter_type()) { }
+#endif
+
+#pragma GCC diagnostic pop
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif /* _BACKWARD_AUTO_PTR_H */
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@@ -0,0 +1,184 @@
+// Functor implementations -*- C++ -*-
+
+// Copyright (C) 2001-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/*
+ *
+ * Copyright (c) 1994
+ * Hewlett-Packard Company
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Hewlett-Packard Company makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ *
+ *
+ * Copyright (c) 1996-1998
+ * Silicon Graphics Computer Systems, Inc.
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Silicon Graphics makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ */
+
+/** @file backward/binders.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{functional}
+ */
+
+#ifndef _BACKWARD_BINDERS_H
+#define _BACKWARD_BINDERS_H 1
+
+// Suppress deprecated warning for this file.
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  // 20.3.6 binders
+  /** @defgroup binders Binder Classes
+   * @ingroup functors
+   *
+   *  Binders turn functions/functors with two arguments into functors
+   *  with a single argument, storing an argument to be applied later.
+   *  For example, a variable @c B of type @c binder1st is constructed
+   *  from a functor @c f and an argument @c x. Later, B's @c
+   *  operator() is called with a single argument @c y. The return
+   *  value is the value of @c f(x,y). @c B can be @a called with
+   *  various arguments (y1, y2, ...) and will in turn call @c
+   *  f(x,y1), @c f(x,y2), ...
+   *
+   *  The function @c bind1st is provided to save some typing. It takes the
+   *  function and an argument as parameters, and returns an instance of
+   *  @c binder1st.
+   *
+   *  The type @c binder2nd and its creator function @c bind2nd do the same
+   *  thing, but the stored argument is passed as the second parameter instead
+   *  of the first, e.g., @c bind2nd(std::minus<float>(),1.3) will create a
+   *  functor whose @c operator() accepts a floating-point number, subtracts
+   *  1.3 from it, and returns the result. (If @c bind1st had been used,
+   *  the functor would perform <em>1.3 - x</em> instead.
+   *
+   *  Creator-wrapper functions like @c bind1st are intended to be used in
+   *  calling algorithms. Their return values will be temporary objects.
+   *  (The goal is to not require you to type names like
+   *  @c std::binder1st<std::plus<int>> for declaring a variable to hold the
+   *  return value from @c bind1st(std::plus<int>(),5).
+   *
+   *  These become more useful when combined with the composition functions.
+   *
+   *  These functions are deprecated in C++11 and can be replaced by
+   *  @c std::bind (or @c std::tr1::bind) which is more powerful and flexible,
+   *  supporting functions with any number of arguments.  Uses of @c bind1st
+   *  can be replaced by @c std::bind(f, x, std::placeholders::_1) and
+   *  @c bind2nd by @c std::bind(f, std::placeholders::_1, x).
+   *  @{
+   */
+  /// One of the @link binders binder functors@endlink.
+  template<typename _Operation>
+    class binder1st
+    : public unary_function<typename _Operation::second_argument_type,
+			    typename _Operation::result_type>
+    {
+    protected:
+      _Operation op;
+      typename _Operation::first_argument_type value;
+
+    public:
+      binder1st(const _Operation& __x,
+		const typename _Operation::first_argument_type& __y)
+      : op(__x), value(__y) { }
+
+      typename _Operation::result_type
+      operator()(const typename _Operation::second_argument_type& __x) const
+      { return op(value, __x); }
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 109.  Missing binders for non-const sequence elements
+      typename _Operation::result_type
+      operator()(typename _Operation::second_argument_type& __x) const
+      { return op(value, __x); }
+    } _GLIBCXX11_DEPRECATED_SUGGEST("std::bind");
+
+  /// One of the @link binders binder functors@endlink.
+  template<typename _Operation, typename _Tp>
+    _GLIBCXX11_DEPRECATED_SUGGEST("std::bind")
+    inline binder1st<_Operation>
+    bind1st(const _Operation& __fn, const _Tp& __x)
+    {
+      typedef typename _Operation::first_argument_type _Arg1_type;
+      return binder1st<_Operation>(__fn, _Arg1_type(__x));
+    }
+
+  /// One of the @link binders binder functors@endlink.
+  template<typename _Operation>
+    class binder2nd
+    : public unary_function<typename _Operation::first_argument_type,
+			    typename _Operation::result_type>
+    {
+    protected:
+      _Operation op;
+      typename _Operation::second_argument_type value;
+
+    public:
+      binder2nd(const _Operation& __x,
+		const typename _Operation::second_argument_type& __y)
+      : op(__x), value(__y) { }
+
+      typename _Operation::result_type
+      operator()(const typename _Operation::first_argument_type& __x) const
+      { return op(__x, value); }
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 109.  Missing binders for non-const sequence elements
+      typename _Operation::result_type
+      operator()(typename _Operation::first_argument_type& __x) const
+      { return op(__x, value); }
+    } _GLIBCXX11_DEPRECATED_SUGGEST("std::bind");
+
+  /// One of the @link binders binder functors@endlink.
+  template<typename _Operation, typename _Tp>
+    _GLIBCXX11_DEPRECATED_SUGGEST("std::bind")
+    inline binder2nd<_Operation>
+    bind2nd(const _Operation& __fn, const _Tp& __x)
+    {
+      typedef typename _Operation::second_argument_type _Arg2_type;
+      return binder2nd<_Operation>(__fn, _Arg2_type(__x));
+    } 
+  /** @}  */
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#pragma GCC diagnostic pop
+
+#endif /* _BACKWARD_BINDERS_H */
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@@ -0,0 +1,480 @@
+// <bit> -*- C++ -*-
+
+// Copyright (C) 2018-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file include/bit
+ *  This is a Standard C++ Library header.
+ */
+
+#ifndef _GLIBCXX_BIT
+#define _GLIBCXX_BIT 1
+
+#pragma GCC system_header
+
+#if __cplusplus >= 201402L
+
+#include <type_traits>
+
+#if _GLIBCXX_HOSTED
+# include <ext/numeric_traits.h>
+#else
+# include <limits>
+/// @cond undocumented
+namespace __gnu_cxx
+{
+  template<typename _Tp>
+    struct __int_traits
+    {
+      static constexpr int __digits = std::numeric_limits<_Tp>::digits;
+      static constexpr _Tp __max = std::numeric_limits<_Tp>::max();
+    };
+}
+/// @endcond
+#endif
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /**
+   * @defgroup bit_manip Bit manipulation
+   * @ingroup numerics
+   *
+   * Utilities for examining and manipulating individual bits.
+   *
+   * @{
+   */
+
+#if __cplusplus > 201703l && __has_builtin(__builtin_bit_cast)
+#define __cpp_lib_bit_cast 201806L
+
+  /// Create a value of type `To` from the bits of `from`.
+  /**
+   * @tparam _To   A trivially-copyable type.
+   * @param __from A trivially-copyable object of the same size as `_To`.
+   * @return       An object of type `_To`.
+   * @since C++20
+   */
+  template<typename _To, typename _From>
+    [[nodiscard]]
+    constexpr _To
+    bit_cast(const _From& __from) noexcept
+#ifdef __cpp_concepts
+    requires (sizeof(_To) == sizeof(_From))
+      && __is_trivially_copyable(_To) && __is_trivially_copyable(_From)
+#endif
+    {
+      return __builtin_bit_cast(_To, __from);
+    }
+#endif
+
+#if __cplusplus > 202002L
+#define __cpp_lib_byteswap 202110L
+
+  /// Reverse order of bytes in the object representation of `value`.
+  /**
+   * @tparam _Tp     An integral type.
+   * @param __value  An object of integer type.
+   * @return         An object of the same type, with the bytes reversed.
+   * @since C++23
+   */
+  template<typename _Tp>
+    [[nodiscard]]
+    constexpr enable_if_t<is_integral<_Tp>::value, _Tp>
+    byteswap(_Tp __value) noexcept
+    {
+      if constexpr (sizeof(_Tp) == 1)
+	return __value;
+#if __cpp_if_consteval >= 202106L && __CHAR_BIT__ == 8
+      if !consteval
+	{
+	  if constexpr (sizeof(_Tp) == 2)
+	    return __builtin_bswap16(__value);
+	  if constexpr (sizeof(_Tp) == 4)
+	    return __builtin_bswap32(__value);
+	  if constexpr (sizeof(_Tp) == 8)
+	    return __builtin_bswap64(__value);
+	  if constexpr (sizeof(_Tp) == 16)
+#if __has_builtin(__builtin_bswap128)
+	    return __builtin_bswap128(__value);
+#else
+	    return (__builtin_bswap64(__value >> 64)
+		    | (static_cast<_Tp>(__builtin_bswap64(__value)) << 64));
+#endif
+	}
+#endif
+
+      // Fallback implementation that handles even __int24 etc.
+      using _Up = typename __make_unsigned<__remove_cv_t<_Tp>>::__type;
+      size_t __diff = __CHAR_BIT__ * (sizeof(_Tp) - 1);
+      _Up __mask1 = static_cast<unsigned char>(~0);
+      _Up __mask2 = __mask1 << __diff;
+      _Up __val = __value;
+      for (size_t __i = 0; __i < sizeof(_Tp) / 2; ++__i)
+	{
+	  _Up __byte1 = __val & __mask1;
+	  _Up __byte2 = __val & __mask2;
+	  __val = (__val ^ __byte1 ^ __byte2
+		   ^ (__byte1 << __diff) ^ (__byte2 >> __diff));
+	  __mask1 <<= __CHAR_BIT__;
+	  __mask2 >>= __CHAR_BIT__;
+	  __diff -= 2 * __CHAR_BIT__;
+	}
+      return __val;
+    }
+#endif
+
+  /// @cond undoc
+
+  template<typename _Tp>
+    constexpr _Tp
+    __rotl(_Tp __x, int __s) noexcept
+    {
+      constexpr auto _Nd = __gnu_cxx::__int_traits<_Tp>::__digits;
+      if _GLIBCXX17_CONSTEXPR ((_Nd & (_Nd - 1)) == 0)
+	{
+	  // Variant for power of two _Nd which the compiler can
+	  // easily pattern match.
+	  constexpr unsigned __uNd = _Nd;
+	  const unsigned __r = __s;
+	  return (__x << (__r % __uNd)) | (__x >> ((-__r) % __uNd));
+	}
+      const int __r = __s % _Nd;
+      if (__r == 0)
+	return __x;
+      else if (__r > 0)
+	return (__x << __r) | (__x >> ((_Nd - __r) % _Nd));
+      else
+	return (__x >> -__r) | (__x << ((_Nd + __r) % _Nd)); // rotr(x, -r)
+    }
+
+  template<typename _Tp>
+    constexpr _Tp
+    __rotr(_Tp __x, int __s) noexcept
+    {
+      constexpr auto _Nd = __gnu_cxx::__int_traits<_Tp>::__digits;
+      if _GLIBCXX17_CONSTEXPR ((_Nd & (_Nd - 1)) == 0)
+	{
+	  // Variant for power of two _Nd which the compiler can
+	  // easily pattern match.
+	  constexpr unsigned __uNd = _Nd;
+	  const unsigned __r = __s;
+	  return (__x >> (__r % __uNd)) | (__x << ((-__r) % __uNd));
+	}
+      const int __r = __s % _Nd;
+      if (__r == 0)
+	return __x;
+      else if (__r > 0)
+	return (__x >> __r) | (__x << ((_Nd - __r) % _Nd));
+      else
+	return (__x << -__r) | (__x >> ((_Nd + __r) % _Nd)); // rotl(x, -r)
+    }
+
+  template<typename _Tp>
+    constexpr int
+    __countl_zero(_Tp __x) noexcept
+    {
+      using __gnu_cxx::__int_traits;
+      constexpr auto _Nd = __int_traits<_Tp>::__digits;
+
+      if (__x == 0)
+        return _Nd;
+
+      constexpr auto _Nd_ull = __int_traits<unsigned long long>::__digits;
+      constexpr auto _Nd_ul = __int_traits<unsigned long>::__digits;
+      constexpr auto _Nd_u = __int_traits<unsigned>::__digits;
+
+      if _GLIBCXX17_CONSTEXPR (_Nd <= _Nd_u)
+	{
+	  constexpr int __diff = _Nd_u - _Nd;
+	  return __builtin_clz(__x) - __diff;
+	}
+      else if _GLIBCXX17_CONSTEXPR (_Nd <= _Nd_ul)
+	{
+	  constexpr int __diff = _Nd_ul - _Nd;
+	  return __builtin_clzl(__x) - __diff;
+	}
+      else if _GLIBCXX17_CONSTEXPR (_Nd <= _Nd_ull)
+	{
+	  constexpr int __diff = _Nd_ull - _Nd;
+	  return __builtin_clzll(__x) - __diff;
+	}
+      else // (_Nd > _Nd_ull)
+	{
+	  static_assert(_Nd <= (2 * _Nd_ull),
+			"Maximum supported integer size is 128-bit");
+
+	  unsigned long long __high = __x >> _Nd_ull;
+	  if (__high != 0)
+	    {
+	      constexpr int __diff = (2 * _Nd_ull) - _Nd;
+	      return __builtin_clzll(__high) - __diff;
+	    }
+	  constexpr auto __max_ull = __int_traits<unsigned long long>::__max;
+	  unsigned long long __low = __x & __max_ull;
+	  return (_Nd - _Nd_ull) + __builtin_clzll(__low);
+	}
+    }
+
+  template<typename _Tp>
+    constexpr int
+    __countl_one(_Tp __x) noexcept
+    {
+      return std::__countl_zero<_Tp>((_Tp)~__x);
+    }
+
+  template<typename _Tp>
+    constexpr int
+    __countr_zero(_Tp __x) noexcept
+    {
+      using __gnu_cxx::__int_traits;
+      constexpr auto _Nd = __int_traits<_Tp>::__digits;
+
+      if (__x == 0)
+        return _Nd;
+
+      constexpr auto _Nd_ull = __int_traits<unsigned long long>::__digits;
+      constexpr auto _Nd_ul = __int_traits<unsigned long>::__digits;
+      constexpr auto _Nd_u = __int_traits<unsigned>::__digits;
+
+      if _GLIBCXX17_CONSTEXPR (_Nd <= _Nd_u)
+	return __builtin_ctz(__x);
+      else if _GLIBCXX17_CONSTEXPR (_Nd <= _Nd_ul)
+	return __builtin_ctzl(__x);
+      else if _GLIBCXX17_CONSTEXPR (_Nd <= _Nd_ull)
+	return __builtin_ctzll(__x);
+      else // (_Nd > _Nd_ull)
+	{
+	  static_assert(_Nd <= (2 * _Nd_ull),
+			"Maximum supported integer size is 128-bit");
+
+	  constexpr auto __max_ull = __int_traits<unsigned long long>::__max;
+	  unsigned long long __low = __x & __max_ull;
+	  if (__low != 0)
+	    return __builtin_ctzll(__low);
+	  unsigned long long __high = __x >> _Nd_ull;
+	  return __builtin_ctzll(__high) + _Nd_ull;
+	}
+    }
+
+  template<typename _Tp>
+    constexpr int
+    __countr_one(_Tp __x) noexcept
+    {
+      return std::__countr_zero((_Tp)~__x);
+    }
+
+  template<typename _Tp>
+    constexpr int
+    __popcount(_Tp __x) noexcept
+    {
+      using __gnu_cxx::__int_traits;
+      constexpr auto _Nd = __int_traits<_Tp>::__digits;
+
+      constexpr auto _Nd_ull = __int_traits<unsigned long long>::__digits;
+      constexpr auto _Nd_ul = __int_traits<unsigned long>::__digits;
+      constexpr auto _Nd_u = __int_traits<unsigned>::__digits;
+
+      if _GLIBCXX17_CONSTEXPR (_Nd <= _Nd_u)
+	return __builtin_popcount(__x);
+      else if _GLIBCXX17_CONSTEXPR (_Nd <= _Nd_ul)
+	return __builtin_popcountl(__x);
+      else if _GLIBCXX17_CONSTEXPR (_Nd <= _Nd_ull)
+	return __builtin_popcountll(__x);
+      else // (_Nd > _Nd_ull)
+	{
+	  static_assert(_Nd <= (2 * _Nd_ull),
+			"Maximum supported integer size is 128-bit");
+
+	  constexpr auto __max_ull = __int_traits<unsigned long long>::__max;
+	  unsigned long long __low = __x & __max_ull;
+	  unsigned long long __high = __x >> _Nd_ull;
+	  return __builtin_popcountll(__low) + __builtin_popcountll(__high);
+	}
+    }
+
+  template<typename _Tp>
+    constexpr bool
+    __has_single_bit(_Tp __x) noexcept
+    { return std::__popcount(__x) == 1; }
+
+  template<typename _Tp>
+    constexpr _Tp
+    __bit_ceil(_Tp __x) noexcept
+    {
+      using __gnu_cxx::__int_traits;
+      constexpr auto _Nd = __int_traits<_Tp>::__digits;
+      if (__x == 0 || __x == 1)
+        return 1;
+      auto __shift_exponent = _Nd - std::__countl_zero((_Tp)(__x - 1u));
+      // If the shift exponent equals _Nd then the correct result is not
+      // representable as a value of _Tp, and so the result is undefined.
+      // Want that undefined behaviour to be detected in constant expressions,
+      // by UBSan, and by debug assertions.
+      if (!std::__is_constant_evaluated())
+	{
+	  __glibcxx_assert( __shift_exponent != __int_traits<_Tp>::__digits );
+	}
+
+      using __promoted_type = decltype(__x << 1);
+      if _GLIBCXX17_CONSTEXPR (!is_same<__promoted_type, _Tp>::value)
+	{
+	  // If __x undergoes integral promotion then shifting by _Nd is
+	  // not undefined. In order to make the shift undefined, so that
+	  // it is diagnosed in constant expressions and by UBsan, we also
+	  // need to "promote" the shift exponent to be too large for the
+	  // promoted type.
+	  const int __extra_exp = sizeof(__promoted_type) / sizeof(_Tp) / 2;
+	  __shift_exponent |= (__shift_exponent & _Nd) << __extra_exp;
+	}
+      return (_Tp)1u << __shift_exponent;
+    }
+
+  template<typename _Tp>
+    constexpr _Tp
+    __bit_floor(_Tp __x) noexcept
+    {
+      constexpr auto _Nd = __gnu_cxx::__int_traits<_Tp>::__digits;
+      if (__x == 0)
+        return 0;
+      return (_Tp)1u << (_Nd - std::__countl_zero((_Tp)(__x >> 1)));
+    }
+
+  template<typename _Tp>
+    constexpr _Tp
+    __bit_width(_Tp __x) noexcept
+    {
+      constexpr auto _Nd = __gnu_cxx::__int_traits<_Tp>::__digits;
+      return _Nd - std::__countl_zero(__x);
+    }
+
+  /// @endcond
+
+#if __cplusplus > 201703L
+
+#define __cpp_lib_bitops 201907L
+
+  /// @cond undoc
+  template<typename _Tp, typename _Up = _Tp>
+    using _If_is_unsigned_integer
+      = enable_if_t<__is_unsigned_integer<_Tp>::value, _Up>;
+  /// @endcond
+
+  // [bit.rot], rotating
+
+  /// Rotate `x` to the left by `s` bits.
+  template<typename _Tp>
+    [[nodiscard]] constexpr _If_is_unsigned_integer<_Tp>
+    rotl(_Tp __x, int __s) noexcept
+    { return std::__rotl(__x, __s); }
+
+  /// Rotate `x` to the right by `s` bits.
+  template<typename _Tp>
+    [[nodiscard]] constexpr _If_is_unsigned_integer<_Tp>
+    rotr(_Tp __x, int __s) noexcept
+    { return std::__rotr(__x, __s); }
+
+  // [bit.count], counting
+
+  /// The number of contiguous zero bits, starting from the highest bit.
+  template<typename _Tp>
+    constexpr _If_is_unsigned_integer<_Tp, int>
+    countl_zero(_Tp __x) noexcept
+    { return std::__countl_zero(__x); }
+
+  /// The number of contiguous one bits, starting from the highest bit.
+  template<typename _Tp>
+    constexpr _If_is_unsigned_integer<_Tp, int>
+    countl_one(_Tp __x) noexcept
+    { return std::__countl_one(__x); }
+
+  /// The number of contiguous zero bits, starting from the lowest bit.
+  template<typename _Tp>
+    constexpr _If_is_unsigned_integer<_Tp, int>
+    countr_zero(_Tp __x) noexcept
+    { return std::__countr_zero(__x); }
+
+  /// The number of contiguous one bits, starting from the lowest bit.
+  template<typename _Tp>
+    constexpr _If_is_unsigned_integer<_Tp, int>
+    countr_one(_Tp __x) noexcept
+    { return std::__countr_one(__x); }
+
+  /// The number of bits set in `x`.
+  template<typename _Tp>
+    constexpr _If_is_unsigned_integer<_Tp, int>
+    popcount(_Tp __x) noexcept
+    { return std::__popcount(__x); }
+
+  // [bit.pow.two], integral powers of 2
+
+#define __cpp_lib_int_pow2 202002L
+
+  /// True if `x` is a power of two, false otherwise.
+  template<typename _Tp>
+    constexpr _If_is_unsigned_integer<_Tp, bool>
+    has_single_bit(_Tp __x) noexcept
+    { return std::__has_single_bit(__x); }
+
+  /// The smallest power-of-two not less than `x`.
+  template<typename _Tp>
+    constexpr _If_is_unsigned_integer<_Tp>
+    bit_ceil(_Tp __x) noexcept
+    { return std::__bit_ceil(__x); }
+
+  /// The largest power-of-two not greater than `x`.
+  template<typename _Tp>
+    constexpr _If_is_unsigned_integer<_Tp>
+    bit_floor(_Tp __x) noexcept
+    { return std::__bit_floor(__x); }
+
+  /// The smallest integer greater than the base-2 logarithm of `x`.
+  template<typename _Tp>
+    constexpr _If_is_unsigned_integer<_Tp>
+    bit_width(_Tp __x) noexcept
+    { return std::__bit_width(__x); }
+
+#define __cpp_lib_endian 201907L
+
+  /// Byte order constants
+  /**
+   * The platform endianness can be checked by comparing `std::endian::native`
+   * to one of `std::endian::big` or `std::endian::little`.
+   *
+   * @since C++20
+   */
+  enum class endian
+  {
+    little = __ORDER_LITTLE_ENDIAN__,
+    big    = __ORDER_BIG_ENDIAN__,
+    native = __BYTE_ORDER__
+  };
+#endif // C++2a
+
+  /// @}
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif // C++14
+#endif // _GLIBCXX_BIT
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@algorithmfwd.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@algorithmfwd.h
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@@ -0,0 +1,967 @@
+// <algorithm> Forward declarations  -*- C++ -*-
+
+// Copyright (C) 2007-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/algorithmfwd.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{algorithm}
+ */
+
+#ifndef _GLIBCXX_ALGORITHMFWD_H
+#define _GLIBCXX_ALGORITHMFWD_H 1
+
+#pragma GCC system_header
+
+#include <bits/c++config.h>
+#include <bits/stl_pair.h>
+#include <bits/stl_iterator_base_types.h>
+#if __cplusplus >= 201103L
+#include <initializer_list>
+#endif
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /*
+    adjacent_find
+    all_of (C++11)
+    any_of (C++11)
+    binary_search
+    clamp (C++17)
+    copy
+    copy_backward
+    copy_if (C++11)
+    copy_n (C++11)
+    count
+    count_if
+    equal
+    equal_range
+    fill
+    fill_n
+    find
+    find_end
+    find_first_of
+    find_if
+    find_if_not (C++11)
+    for_each
+    generate
+    generate_n
+    includes
+    inplace_merge
+    is_heap (C++11)
+    is_heap_until (C++11)
+    is_partitioned (C++11)
+    is_sorted (C++11)
+    is_sorted_until (C++11)
+    iter_swap
+    lexicographical_compare
+    lower_bound
+    make_heap
+    max
+    max_element
+    merge
+    min
+    min_element
+    minmax (C++11)
+    minmax_element (C++11)
+    mismatch
+    next_permutation
+    none_of (C++11)
+    nth_element
+    partial_sort
+    partial_sort_copy
+    partition
+    partition_copy (C++11)
+    partition_point (C++11)
+    pop_heap
+    prev_permutation
+    push_heap
+    random_shuffle
+    remove
+    remove_copy
+    remove_copy_if
+    remove_if
+    replace
+    replace_copy
+    replace_copy_if
+    replace_if
+    reverse
+    reverse_copy
+    rotate
+    rotate_copy
+    search
+    search_n
+    set_difference
+    set_intersection
+    set_symmetric_difference
+    set_union
+    shuffle (C++11)
+    sort
+    sort_heap
+    stable_partition
+    stable_sort
+    swap
+    swap_ranges
+    transform
+    unique
+    unique_copy
+    upper_bound
+  */
+
+  /**
+   * @defgroup algorithms Algorithms
+   *
+   * Components for performing algorithmic operations. Includes
+   * non-modifying sequence, modifying (mutating) sequence, sorting,
+   * searching, merge, partition, heap, set, minima, maxima, and
+   * permutation operations.
+   */
+
+  /**
+   * @defgroup mutating_algorithms Mutating
+   * @ingroup algorithms
+   */
+
+  /**
+   * @defgroup non_mutating_algorithms Non-Mutating
+   * @ingroup algorithms
+   */
+
+  /**
+   * @defgroup sorting_algorithms Sorting
+   * @ingroup algorithms
+   */
+
+  /**
+   * @defgroup set_algorithms Set Operations
+   * @ingroup sorting_algorithms
+   *
+   * These algorithms are common set operations performed on sequences
+   * that are already sorted. The number of comparisons will be
+   * linear.
+   */
+
+  /**
+   * @defgroup binary_search_algorithms Binary Search
+   * @ingroup sorting_algorithms
+   *
+   * These algorithms are variations of a classic binary search, and
+   * all assume that the sequence being searched is already sorted.
+   *
+   * The number of comparisons will be logarithmic (and as few as
+   * possible).  The number of steps through the sequence will be
+   * logarithmic for random-access iterators (e.g., pointers), and
+   * linear otherwise.
+   *
+   * The LWG has passed Defect Report 270, which notes: <em>The
+   * proposed resolution reinterprets binary search. Instead of
+   * thinking about searching for a value in a sorted range, we view
+   * that as an important special case of a more general algorithm:
+   * searching for the partition point in a partitioned range.  We
+   * also add a guarantee that the old wording did not: we ensure that
+   * the upper bound is no earlier than the lower bound, that the pair
+   * returned by equal_range is a valid range, and that the first part
+   * of that pair is the lower bound.</em>
+   *
+   * The actual effect of the first sentence is that a comparison
+   * functor passed by the user doesn't necessarily need to induce a
+   * strict weak ordering relation.  Rather, it partitions the range.
+   */
+
+  // adjacent_find
+
+#if __cplusplus > 201703L
+#  define __cpp_lib_constexpr_algorithms 201806L
+#endif
+
+#if __cplusplus >= 201103L
+  template<typename _IIter, typename _Predicate>
+    _GLIBCXX20_CONSTEXPR
+    bool
+    all_of(_IIter, _IIter, _Predicate);
+
+  template<typename _IIter, typename _Predicate>
+    _GLIBCXX20_CONSTEXPR
+    bool
+    any_of(_IIter, _IIter, _Predicate);
+#endif
+
+  template<typename _FIter, typename _Tp>
+    _GLIBCXX20_CONSTEXPR
+    bool
+    binary_search(_FIter, _FIter, const _Tp&);
+
+  template<typename _FIter, typename _Tp, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    bool
+    binary_search(_FIter, _FIter, const _Tp&, _Compare);
+
+#if __cplusplus > 201402L
+  template<typename _Tp>
+    _GLIBCXX14_CONSTEXPR
+    const _Tp&
+    clamp(const _Tp&, const _Tp&, const _Tp&);
+
+  template<typename _Tp, typename _Compare>
+    _GLIBCXX14_CONSTEXPR
+    const _Tp&
+    clamp(const _Tp&, const _Tp&, const _Tp&, _Compare);
+#endif
+
+  template<typename _IIter, typename _OIter>
+    _GLIBCXX20_CONSTEXPR
+    _OIter
+    copy(_IIter, _IIter, _OIter);
+
+  template<typename _BIter1, typename _BIter2>
+    _GLIBCXX20_CONSTEXPR
+    _BIter2
+    copy_backward(_BIter1, _BIter1, _BIter2);
+
+#if __cplusplus >= 201103L
+  template<typename _IIter, typename _OIter, typename _Predicate>
+    _GLIBCXX20_CONSTEXPR
+    _OIter
+    copy_if(_IIter, _IIter, _OIter, _Predicate);
+
+  template<typename _IIter, typename _Size, typename _OIter>
+    _GLIBCXX20_CONSTEXPR
+    _OIter
+    copy_n(_IIter, _Size, _OIter);
+#endif
+
+  // count
+  // count_if
+
+  template<typename _FIter, typename _Tp>
+    _GLIBCXX20_CONSTEXPR
+    pair<_FIter, _FIter>
+    equal_range(_FIter, _FIter, const _Tp&);
+
+  template<typename _FIter, typename _Tp, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    pair<_FIter, _FIter>
+    equal_range(_FIter, _FIter, const _Tp&, _Compare);
+
+  template<typename _FIter, typename _Tp>
+    _GLIBCXX20_CONSTEXPR
+    void
+    fill(_FIter, _FIter, const _Tp&);
+
+  template<typename _OIter, typename _Size, typename _Tp>
+    _GLIBCXX20_CONSTEXPR
+    _OIter
+    fill_n(_OIter, _Size, const _Tp&);
+
+  // find
+
+  template<typename _FIter1, typename _FIter2>
+    _GLIBCXX20_CONSTEXPR
+    _FIter1
+    find_end(_FIter1, _FIter1, _FIter2, _FIter2);
+
+  template<typename _FIter1, typename _FIter2, typename _BinaryPredicate>
+    _GLIBCXX20_CONSTEXPR
+    _FIter1
+    find_end(_FIter1, _FIter1, _FIter2, _FIter2, _BinaryPredicate);
+
+  // find_first_of
+  // find_if
+
+#if __cplusplus >= 201103L
+  template<typename _IIter, typename _Predicate>
+    _GLIBCXX20_CONSTEXPR
+    _IIter
+    find_if_not(_IIter, _IIter, _Predicate);
+#endif
+
+  // for_each
+  // generate
+  // generate_n
+
+  template<typename _IIter1, typename _IIter2>
+    _GLIBCXX20_CONSTEXPR
+    bool
+    includes(_IIter1, _IIter1, _IIter2, _IIter2);
+
+  template<typename _IIter1, typename _IIter2, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    bool
+    includes(_IIter1, _IIter1, _IIter2, _IIter2, _Compare);
+
+  template<typename _BIter>
+    void
+    inplace_merge(_BIter, _BIter, _BIter);
+
+  template<typename _BIter, typename _Compare>
+    void
+    inplace_merge(_BIter, _BIter, _BIter, _Compare);
+
+#if __cplusplus >= 201103L
+  template<typename _RAIter>
+    _GLIBCXX20_CONSTEXPR
+    bool
+    is_heap(_RAIter, _RAIter);
+
+  template<typename _RAIter, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    bool
+    is_heap(_RAIter, _RAIter, _Compare);
+
+  template<typename _RAIter>
+    _GLIBCXX20_CONSTEXPR
+    _RAIter
+    is_heap_until(_RAIter, _RAIter);
+
+  template<typename _RAIter, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    _RAIter
+    is_heap_until(_RAIter, _RAIter, _Compare);
+
+  template<typename _IIter, typename _Predicate>
+    _GLIBCXX20_CONSTEXPR
+    bool
+    is_partitioned(_IIter, _IIter, _Predicate);
+
+  template<typename _FIter1, typename _FIter2>
+    _GLIBCXX20_CONSTEXPR
+    bool
+    is_permutation(_FIter1, _FIter1, _FIter2);
+
+  template<typename _FIter1, typename _FIter2,
+	   typename _BinaryPredicate>
+    _GLIBCXX20_CONSTEXPR
+    bool
+    is_permutation(_FIter1, _FIter1, _FIter2, _BinaryPredicate);
+
+  template<typename _FIter>
+    _GLIBCXX20_CONSTEXPR
+    bool
+    is_sorted(_FIter, _FIter);
+
+  template<typename _FIter, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    bool
+    is_sorted(_FIter, _FIter, _Compare);
+
+  template<typename _FIter>
+    _GLIBCXX20_CONSTEXPR
+    _FIter
+    is_sorted_until(_FIter, _FIter);
+
+  template<typename _FIter, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    _FIter
+    is_sorted_until(_FIter, _FIter, _Compare);
+#endif
+
+  template<typename _FIter1, typename _FIter2>
+    _GLIBCXX20_CONSTEXPR
+    void
+    iter_swap(_FIter1, _FIter2);
+
+  template<typename _FIter, typename _Tp>
+    _GLIBCXX20_CONSTEXPR
+    _FIter
+    lower_bound(_FIter, _FIter, const _Tp&);
+
+  template<typename _FIter, typename _Tp, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    _FIter
+    lower_bound(_FIter, _FIter, const _Tp&, _Compare);
+
+  template<typename _RAIter>
+    _GLIBCXX20_CONSTEXPR
+    void
+    make_heap(_RAIter, _RAIter);
+
+  template<typename _RAIter, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    void
+    make_heap(_RAIter, _RAIter, _Compare);
+
+  template<typename _Tp>
+    _GLIBCXX14_CONSTEXPR
+    const _Tp&
+    max(const _Tp&, const _Tp&);
+
+  template<typename _Tp, typename _Compare>
+    _GLIBCXX14_CONSTEXPR
+    const _Tp&
+    max(const _Tp&, const _Tp&, _Compare);
+
+  // max_element
+  // merge
+
+  template<typename _Tp>
+    _GLIBCXX14_CONSTEXPR
+    const _Tp&
+    min(const _Tp&, const _Tp&);
+
+  template<typename _Tp, typename _Compare>
+    _GLIBCXX14_CONSTEXPR
+    const _Tp&
+    min(const _Tp&, const _Tp&, _Compare);
+
+  // min_element
+
+#if __cplusplus >= 201103L
+  template<typename _Tp>
+    _GLIBCXX14_CONSTEXPR
+    pair<const _Tp&, const _Tp&>
+    minmax(const _Tp&, const _Tp&);
+
+  template<typename _Tp, typename _Compare>
+    _GLIBCXX14_CONSTEXPR
+    pair<const _Tp&, const _Tp&>
+    minmax(const _Tp&, const _Tp&, _Compare);
+
+  template<typename _FIter>
+    _GLIBCXX14_CONSTEXPR
+    pair<_FIter, _FIter>
+    minmax_element(_FIter, _FIter);
+
+  template<typename _FIter, typename _Compare>
+    _GLIBCXX14_CONSTEXPR
+    pair<_FIter, _FIter>
+    minmax_element(_FIter, _FIter, _Compare);
+
+  template<typename _Tp>
+    _GLIBCXX14_CONSTEXPR
+    _Tp
+    min(initializer_list<_Tp>);
+
+  template<typename _Tp, typename _Compare>
+    _GLIBCXX14_CONSTEXPR
+    _Tp
+    min(initializer_list<_Tp>, _Compare);
+
+  template<typename _Tp>
+    _GLIBCXX14_CONSTEXPR
+    _Tp
+    max(initializer_list<_Tp>);
+
+  template<typename _Tp, typename _Compare>
+    _GLIBCXX14_CONSTEXPR
+    _Tp
+    max(initializer_list<_Tp>, _Compare);
+
+  template<typename _Tp>
+    _GLIBCXX14_CONSTEXPR
+    pair<_Tp, _Tp>
+    minmax(initializer_list<_Tp>);
+
+  template<typename _Tp, typename _Compare>
+    _GLIBCXX14_CONSTEXPR
+    pair<_Tp, _Tp>
+    minmax(initializer_list<_Tp>, _Compare);
+#endif
+
+  // mismatch
+
+  template<typename _BIter>
+    _GLIBCXX20_CONSTEXPR
+    bool
+    next_permutation(_BIter, _BIter);
+
+  template<typename _BIter, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    bool
+    next_permutation(_BIter, _BIter, _Compare);
+
+#if __cplusplus >= 201103L
+  template<typename _IIter, typename _Predicate>
+    _GLIBCXX20_CONSTEXPR
+    bool
+    none_of(_IIter, _IIter, _Predicate);
+#endif
+
+  // nth_element
+  // partial_sort
+
+  template<typename _IIter, typename _RAIter>
+    _GLIBCXX20_CONSTEXPR
+    _RAIter
+    partial_sort_copy(_IIter, _IIter, _RAIter, _RAIter);
+
+  template<typename _IIter, typename _RAIter, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    _RAIter
+    partial_sort_copy(_IIter, _IIter, _RAIter, _RAIter, _Compare);
+
+  // partition
+
+#if __cplusplus >= 201103L
+  template<typename _IIter, typename _OIter1,
+	   typename _OIter2, typename _Predicate>
+    _GLIBCXX20_CONSTEXPR
+    pair<_OIter1, _OIter2>
+    partition_copy(_IIter, _IIter, _OIter1, _OIter2, _Predicate);
+
+  template<typename _FIter, typename _Predicate>
+    _GLIBCXX20_CONSTEXPR
+    _FIter
+    partition_point(_FIter, _FIter, _Predicate);
+#endif
+
+  template<typename _RAIter>
+    _GLIBCXX20_CONSTEXPR
+    void
+    pop_heap(_RAIter, _RAIter);
+
+  template<typename _RAIter, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    void
+    pop_heap(_RAIter, _RAIter, _Compare);
+
+  template<typename _BIter>
+    _GLIBCXX20_CONSTEXPR
+    bool
+    prev_permutation(_BIter, _BIter);
+
+  template<typename _BIter, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    bool
+    prev_permutation(_BIter, _BIter, _Compare);
+
+  template<typename _RAIter>
+    _GLIBCXX20_CONSTEXPR
+    void
+    push_heap(_RAIter, _RAIter);
+
+  template<typename _RAIter, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    void
+    push_heap(_RAIter, _RAIter, _Compare);
+
+  // random_shuffle
+
+  template<typename _FIter, typename _Tp>
+    _GLIBCXX20_CONSTEXPR
+    _FIter
+    remove(_FIter, _FIter, const _Tp&);
+
+  template<typename _FIter, typename _Predicate>
+    _GLIBCXX20_CONSTEXPR
+    _FIter
+    remove_if(_FIter, _FIter, _Predicate);
+
+  template<typename _IIter, typename _OIter, typename _Tp>
+    _GLIBCXX20_CONSTEXPR
+    _OIter
+    remove_copy(_IIter, _IIter, _OIter, const _Tp&);
+
+  template<typename _IIter, typename _OIter, typename _Predicate>
+    _GLIBCXX20_CONSTEXPR
+    _OIter
+    remove_copy_if(_IIter, _IIter, _OIter, _Predicate);
+
+  // replace
+
+  template<typename _IIter, typename _OIter, typename _Tp>
+    _GLIBCXX20_CONSTEXPR
+    _OIter
+    replace_copy(_IIter, _IIter, _OIter, const _Tp&, const _Tp&);
+
+  template<typename _Iter, typename _OIter, typename _Predicate, typename _Tp>
+    _GLIBCXX20_CONSTEXPR
+    _OIter
+    replace_copy_if(_Iter, _Iter, _OIter, _Predicate, const _Tp&);
+
+  // replace_if
+
+  template<typename _BIter>
+    _GLIBCXX20_CONSTEXPR
+    void
+    reverse(_BIter, _BIter);
+
+  template<typename _BIter, typename _OIter>
+    _GLIBCXX20_CONSTEXPR
+    _OIter
+    reverse_copy(_BIter, _BIter, _OIter);
+
+  inline namespace _V2
+  {
+    template<typename _FIter>
+      _GLIBCXX20_CONSTEXPR
+      _FIter
+      rotate(_FIter, _FIter, _FIter);
+  }
+
+  template<typename _FIter, typename _OIter>
+    _GLIBCXX20_CONSTEXPR
+    _OIter
+    rotate_copy(_FIter, _FIter, _FIter, _OIter);
+
+  // search
+  // search_n
+  // set_difference
+  // set_intersection
+  // set_symmetric_difference
+  // set_union
+
+#if (__cplusplus >= 201103L) && defined(_GLIBCXX_USE_C99_STDINT_TR1)
+  template<typename _RAIter, typename _UGenerator>
+    void
+    shuffle(_RAIter, _RAIter, _UGenerator&&);
+#endif
+
+  template<typename _RAIter>
+    _GLIBCXX20_CONSTEXPR
+    void
+    sort_heap(_RAIter, _RAIter);
+
+  template<typename _RAIter, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    void
+    sort_heap(_RAIter, _RAIter, _Compare);
+
+  template<typename _BIter, typename _Predicate>
+    _BIter
+    stable_partition(_BIter, _BIter, _Predicate);
+
+#if __cplusplus < 201103L
+  // For C++11 swap() is declared in <type_traits>.
+
+  template<typename _Tp, size_t _Nm>
+    _GLIBCXX20_CONSTEXPR
+    inline void
+    swap(_Tp& __a, _Tp& __b);
+
+  template<typename _Tp, size_t _Nm>
+    _GLIBCXX20_CONSTEXPR
+    inline void
+    swap(_Tp (&__a)[_Nm], _Tp (&__b)[_Nm]);
+#endif
+
+  template<typename _FIter1, typename _FIter2>
+    _GLIBCXX20_CONSTEXPR
+    _FIter2
+    swap_ranges(_FIter1, _FIter1, _FIter2);
+
+  // transform
+
+  template<typename _FIter>
+    _GLIBCXX20_CONSTEXPR
+    _FIter
+    unique(_FIter, _FIter);
+
+  template<typename _FIter, typename _BinaryPredicate>
+    _GLIBCXX20_CONSTEXPR
+    _FIter
+    unique(_FIter, _FIter, _BinaryPredicate);
+
+  // unique_copy
+
+  template<typename _FIter, typename _Tp>
+    _GLIBCXX20_CONSTEXPR
+    _FIter
+    upper_bound(_FIter, _FIter, const _Tp&);
+
+  template<typename _FIter, typename _Tp, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    _FIter
+    upper_bound(_FIter, _FIter, const _Tp&, _Compare);
+
+_GLIBCXX_BEGIN_NAMESPACE_ALGO
+
+  template<typename _FIter>
+    _GLIBCXX20_CONSTEXPR
+    _FIter
+    adjacent_find(_FIter, _FIter);
+
+  template<typename _FIter, typename _BinaryPredicate>
+    _GLIBCXX20_CONSTEXPR
+    _FIter
+    adjacent_find(_FIter, _FIter, _BinaryPredicate);
+
+  template<typename _IIter, typename _Tp>
+    _GLIBCXX20_CONSTEXPR
+    typename iterator_traits<_IIter>::difference_type
+    count(_IIter, _IIter, const _Tp&);
+
+  template<typename _IIter, typename _Predicate>
+    _GLIBCXX20_CONSTEXPR
+    typename iterator_traits<_IIter>::difference_type
+    count_if(_IIter, _IIter, _Predicate);
+
+  template<typename _IIter1, typename _IIter2>
+    _GLIBCXX20_CONSTEXPR
+    bool
+    equal(_IIter1, _IIter1, _IIter2);
+
+  template<typename _IIter1, typename _IIter2, typename _BinaryPredicate>
+    _GLIBCXX20_CONSTEXPR
+    bool
+    equal(_IIter1, _IIter1, _IIter2, _BinaryPredicate);
+
+  template<typename _IIter, typename _Tp>
+    _GLIBCXX20_CONSTEXPR
+    _IIter
+    find(_IIter, _IIter, const _Tp&);
+
+  template<typename _FIter1, typename _FIter2>
+    _GLIBCXX20_CONSTEXPR
+    _FIter1
+    find_first_of(_FIter1, _FIter1, _FIter2, _FIter2);
+
+  template<typename _FIter1, typename _FIter2, typename _BinaryPredicate>
+    _GLIBCXX20_CONSTEXPR
+    _FIter1
+    find_first_of(_FIter1, _FIter1, _FIter2, _FIter2, _BinaryPredicate);
+
+  template<typename _IIter, typename _Predicate>
+    _GLIBCXX20_CONSTEXPR
+    _IIter
+    find_if(_IIter, _IIter, _Predicate);
+
+  template<typename _IIter, typename _Funct>
+    _GLIBCXX20_CONSTEXPR
+    _Funct
+    for_each(_IIter, _IIter, _Funct);
+
+  template<typename _FIter, typename _Generator>
+    _GLIBCXX20_CONSTEXPR
+    void
+    generate(_FIter, _FIter, _Generator);
+
+  template<typename _OIter, typename _Size, typename _Generator>
+    _GLIBCXX20_CONSTEXPR
+    _OIter
+    generate_n(_OIter, _Size, _Generator);
+
+  template<typename _IIter1, typename _IIter2>
+    _GLIBCXX20_CONSTEXPR
+    bool
+    lexicographical_compare(_IIter1, _IIter1, _IIter2, _IIter2);
+
+  template<typename _IIter1, typename _IIter2, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    bool
+    lexicographical_compare(_IIter1, _IIter1, _IIter2, _IIter2, _Compare);
+
+  template<typename _FIter>
+    _GLIBCXX14_CONSTEXPR
+    _FIter
+    max_element(_FIter, _FIter);
+
+  template<typename _FIter, typename _Compare>
+    _GLIBCXX14_CONSTEXPR
+    _FIter
+    max_element(_FIter, _FIter, _Compare);
+
+  template<typename _IIter1, typename _IIter2, typename _OIter>
+    _GLIBCXX20_CONSTEXPR
+    _OIter
+    merge(_IIter1, _IIter1, _IIter2, _IIter2, _OIter);
+
+  template<typename _IIter1, typename _IIter2, typename _OIter,
+	   typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    _OIter
+    merge(_IIter1, _IIter1, _IIter2, _IIter2, _OIter, _Compare);
+
+  template<typename _FIter>
+    _GLIBCXX14_CONSTEXPR
+    _FIter
+    min_element(_FIter, _FIter);
+
+  template<typename _FIter, typename _Compare>
+    _GLIBCXX14_CONSTEXPR
+    _FIter
+    min_element(_FIter, _FIter, _Compare);
+
+  template<typename _IIter1, typename _IIter2>
+    _GLIBCXX20_CONSTEXPR
+    pair<_IIter1, _IIter2>
+    mismatch(_IIter1, _IIter1, _IIter2);
+
+  template<typename _IIter1, typename _IIter2, typename _BinaryPredicate>
+    _GLIBCXX20_CONSTEXPR
+    pair<_IIter1, _IIter2>
+    mismatch(_IIter1, _IIter1, _IIter2, _BinaryPredicate);
+
+  template<typename _RAIter>
+    _GLIBCXX20_CONSTEXPR
+    void
+    nth_element(_RAIter, _RAIter, _RAIter);
+
+  template<typename _RAIter, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    void
+    nth_element(_RAIter, _RAIter, _RAIter, _Compare);
+
+  template<typename _RAIter>
+    _GLIBCXX20_CONSTEXPR
+    void
+    partial_sort(_RAIter, _RAIter, _RAIter);
+
+  template<typename _RAIter, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    void
+    partial_sort(_RAIter, _RAIter, _RAIter, _Compare);
+
+  template<typename _BIter, typename _Predicate>
+    _GLIBCXX20_CONSTEXPR
+    _BIter
+    partition(_BIter, _BIter, _Predicate);
+
+  template<typename _RAIter>
+    void
+    random_shuffle(_RAIter, _RAIter);
+
+  template<typename _RAIter, typename _Generator>
+    void
+    random_shuffle(_RAIter, _RAIter,
+#if __cplusplus >= 201103L
+		   _Generator&&);
+#else
+		   _Generator&);
+#endif
+
+  template<typename _FIter, typename _Tp>
+    _GLIBCXX20_CONSTEXPR
+    void
+    replace(_FIter, _FIter, const _Tp&, const _Tp&);
+
+  template<typename _FIter, typename _Predicate, typename _Tp>
+    _GLIBCXX20_CONSTEXPR
+    void
+    replace_if(_FIter, _FIter, _Predicate, const _Tp&);
+
+  template<typename _FIter1, typename _FIter2>
+    _GLIBCXX20_CONSTEXPR
+    _FIter1
+    search(_FIter1, _FIter1, _FIter2, _FIter2);
+
+  template<typename _FIter1, typename _FIter2, typename _BinaryPredicate>
+    _GLIBCXX20_CONSTEXPR
+    _FIter1
+    search(_FIter1, _FIter1, _FIter2, _FIter2, _BinaryPredicate);
+
+  template<typename _FIter, typename _Size, typename _Tp>
+    _GLIBCXX20_CONSTEXPR
+    _FIter
+    search_n(_FIter, _FIter, _Size, const _Tp&);
+
+  template<typename _FIter, typename _Size, typename _Tp,
+	   typename _BinaryPredicate>
+    _GLIBCXX20_CONSTEXPR
+    _FIter
+    search_n(_FIter, _FIter, _Size, const _Tp&, _BinaryPredicate);
+
+  template<typename _IIter1, typename _IIter2, typename _OIter>
+    _GLIBCXX20_CONSTEXPR
+    _OIter
+    set_difference(_IIter1, _IIter1, _IIter2, _IIter2, _OIter);
+
+  template<typename _IIter1, typename _IIter2, typename _OIter,
+	   typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    _OIter
+    set_difference(_IIter1, _IIter1, _IIter2, _IIter2, _OIter, _Compare);
+
+  template<typename _IIter1, typename _IIter2, typename _OIter>
+    _GLIBCXX20_CONSTEXPR
+    _OIter
+    set_intersection(_IIter1, _IIter1, _IIter2, _IIter2, _OIter);
+
+  template<typename _IIter1, typename _IIter2, typename _OIter,
+	   typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    _OIter
+    set_intersection(_IIter1, _IIter1, _IIter2, _IIter2, _OIter, _Compare);
+
+  template<typename _IIter1, typename _IIter2, typename _OIter>
+    _GLIBCXX20_CONSTEXPR
+    _OIter
+    set_symmetric_difference(_IIter1, _IIter1, _IIter2, _IIter2, _OIter);
+
+  template<typename _IIter1, typename _IIter2, typename _OIter,
+	   typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    _OIter
+    set_symmetric_difference(_IIter1, _IIter1, _IIter2, _IIter2,
+			     _OIter, _Compare);
+
+  template<typename _IIter1, typename _IIter2, typename _OIter>
+    _GLIBCXX20_CONSTEXPR
+    _OIter
+    set_union(_IIter1, _IIter1, _IIter2, _IIter2, _OIter);
+
+  template<typename _IIter1, typename _IIter2, typename _OIter,
+	   typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    _OIter
+    set_union(_IIter1, _IIter1, _IIter2, _IIter2, _OIter, _Compare);
+
+  template<typename _RAIter>
+    _GLIBCXX20_CONSTEXPR
+    void
+    sort(_RAIter, _RAIter);
+
+  template<typename _RAIter, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    void
+    sort(_RAIter, _RAIter, _Compare);
+
+  template<typename _RAIter>
+    void
+    stable_sort(_RAIter, _RAIter);
+
+  template<typename _RAIter, typename _Compare>
+    void
+    stable_sort(_RAIter, _RAIter, _Compare);
+
+  template<typename _IIter, typename _OIter, typename _UnaryOperation>
+    _GLIBCXX20_CONSTEXPR
+    _OIter
+    transform(_IIter, _IIter, _OIter, _UnaryOperation);
+
+  template<typename _IIter1, typename _IIter2, typename _OIter,
+	   typename _BinaryOperation>
+    _GLIBCXX20_CONSTEXPR
+    _OIter
+    transform(_IIter1, _IIter1, _IIter2, _OIter, _BinaryOperation);
+
+  template<typename _IIter, typename _OIter>
+    _GLIBCXX20_CONSTEXPR
+    _OIter
+    unique_copy(_IIter, _IIter, _OIter);
+
+  template<typename _IIter, typename _OIter, typename _BinaryPredicate>
+    _GLIBCXX20_CONSTEXPR
+    _OIter
+    unique_copy(_IIter, _IIter, _OIter, _BinaryPredicate);
+
+_GLIBCXX_END_NAMESPACE_ALGO
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#ifdef _GLIBCXX_PARALLEL
+# include <parallel/algorithmfwd.h>
+#endif
+
+#endif
+
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@@ -0,0 +1,111 @@
+// align implementation -*- C++ -*-
+
+// Copyright (C) 2014-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/align.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{memory}
+ */
+
+#ifndef _GLIBCXX_ALIGN_H
+#define _GLIBCXX_ALIGN_H 1
+
+#include <bits/c++config.h>
+
+#include <bit>          // std::has_single_bit
+#include <stdint.h>     // uintptr_t
+#include <debug/assertions.h> // _GLIBCXX_DEBUG_ASSERT
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+/**
+ *  @brief Fit aligned storage in buffer.
+ *
+ *  This function tries to fit @a __size bytes of storage with alignment
+ *  @a __align into the buffer @a __ptr of size @a __space bytes.  If such
+ *  a buffer fits then @a __ptr is changed to point to the first byte of the
+ *  aligned storage and @a __space is reduced by the bytes used for alignment.
+ *
+ *  C++11 20.6.5 [ptr.align]
+ *
+ *  @param __align   A fundamental or extended alignment value.
+ *  @param __size    Size of the aligned storage required.
+ *  @param __ptr     Pointer to a buffer of @a __space bytes.
+ *  @param __space   Size of the buffer pointed to by @a __ptr.
+ *  @return the updated pointer if the aligned storage fits, otherwise nullptr.
+ *
+ *  @ingroup memory
+ */
+inline void*
+align(size_t __align, size_t __size, void*& __ptr, size_t& __space) noexcept
+{
+  if (__space < __size)
+    return nullptr;
+  const auto __intptr = reinterpret_cast<uintptr_t>(__ptr);
+  const auto __aligned = (__intptr - 1u + __align) & -__align;
+  const auto __diff = __aligned - __intptr;
+  if (__diff > (__space - __size))
+    return nullptr;
+  else
+    {
+      __space -= __diff;
+      return __ptr = reinterpret_cast<void*>(__aligned);
+    }
+}
+
+#if __cplusplus > 201703L
+#define __cpp_lib_assume_aligned 201811L
+  /** @brief Inform the compiler that a pointer is aligned.
+   *
+   *  @tparam _Align An alignment value (i.e. a power of two)
+   *  @tparam _Tp    An object type
+   *  @param  __ptr  A pointer that is aligned to _Align
+   *
+   *  C++20 20.10.6 [ptr.align]
+   *
+   *  @ingroup memory
+   */
+  template<size_t _Align, class _Tp>
+    [[nodiscard,__gnu__::__always_inline__]]
+    constexpr _Tp*
+    assume_aligned(_Tp* __ptr) noexcept
+    {
+      static_assert(std::has_single_bit(_Align));
+      if (std::is_constant_evaluated())
+	return __ptr;
+      else
+	{
+	  // This function is expected to be used in hot code, where
+	  // __glibcxx_assert would add unwanted overhead.
+	  _GLIBCXX_DEBUG_ASSERT((uintptr_t)__ptr % _Align == 0);
+	  return static_cast<_Tp*>(__builtin_assume_aligned(__ptr, _Align));
+	}
+    }
+#endif // C++2a
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif /* _GLIBCXX_ALIGN_H */
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@@ -0,0 +1,855 @@
+// Allocator traits -*- C++ -*-
+
+// Copyright (C) 2011-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/alloc_traits.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{memory}
+ */
+
+#ifndef _ALLOC_TRAITS_H
+#define _ALLOC_TRAITS_H 1
+
+#include <bits/stl_construct.h>
+#include <bits/memoryfwd.h>
+#if __cplusplus >= 201103L
+# include <bits/allocator.h>
+# include <bits/ptr_traits.h>
+# include <ext/numeric_traits.h>
+#endif
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+#if __cplusplus >= 201103L
+#define __cpp_lib_allocator_traits_is_always_equal 201411L
+
+  /// @cond undocumented
+  struct __allocator_traits_base
+  {
+    template<typename _Tp, typename _Up, typename = void>
+      struct __rebind : __replace_first_arg<_Tp, _Up> { };
+
+    template<typename _Tp, typename _Up>
+      struct __rebind<_Tp, _Up,
+		      __void_t<typename _Tp::template rebind<_Up>::other>>
+      { using type = typename _Tp::template rebind<_Up>::other; };
+
+  protected:
+    template<typename _Tp>
+      using __pointer = typename _Tp::pointer;
+    template<typename _Tp>
+      using __c_pointer = typename _Tp::const_pointer;
+    template<typename _Tp>
+      using __v_pointer = typename _Tp::void_pointer;
+    template<typename _Tp>
+      using __cv_pointer = typename _Tp::const_void_pointer;
+    template<typename _Tp>
+      using __pocca = typename _Tp::propagate_on_container_copy_assignment;
+    template<typename _Tp>
+      using __pocma = typename _Tp::propagate_on_container_move_assignment;
+    template<typename _Tp>
+      using __pocs = typename _Tp::propagate_on_container_swap;
+    template<typename _Tp>
+      using __equal = typename _Tp::is_always_equal;
+  };
+
+  template<typename _Alloc, typename _Up>
+    using __alloc_rebind
+      = typename __allocator_traits_base::template __rebind<_Alloc, _Up>::type;
+  /// @endcond
+
+  /**
+   * @brief  Uniform interface to all allocator types.
+   * @headerfile memory
+   * @ingroup allocators
+   * @since C++11
+  */
+  template<typename _Alloc>
+    struct allocator_traits : __allocator_traits_base
+    {
+      /// The allocator type
+      typedef _Alloc allocator_type;
+      /// The allocated type
+      typedef typename _Alloc::value_type value_type;
+
+      /**
+       * @brief   The allocator's pointer type.
+       *
+       * @c Alloc::pointer if that type exists, otherwise @c value_type*
+      */
+      using pointer = __detected_or_t<value_type*, __pointer, _Alloc>;
+
+    private:
+      // Select _Func<_Alloc> or pointer_traits<pointer>::rebind<_Tp>
+      template<template<typename> class _Func, typename _Tp, typename = void>
+	struct _Ptr
+	{
+	  using type = typename pointer_traits<pointer>::template rebind<_Tp>;
+	};
+
+      template<template<typename> class _Func, typename _Tp>
+	struct _Ptr<_Func, _Tp, __void_t<_Func<_Alloc>>>
+	{
+	  using type = _Func<_Alloc>;
+	};
+
+      // Select _A2::difference_type or pointer_traits<_Ptr>::difference_type
+      template<typename _A2, typename _PtrT, typename = void>
+	struct _Diff
+	{ using type = typename pointer_traits<_PtrT>::difference_type; };
+
+      template<typename _A2, typename _PtrT>
+	struct _Diff<_A2, _PtrT, __void_t<typename _A2::difference_type>>
+	{ using type = typename _A2::difference_type; };
+
+      // Select _A2::size_type or make_unsigned<_DiffT>::type
+      template<typename _A2, typename _DiffT, typename = void>
+	struct _Size : make_unsigned<_DiffT> { };
+
+      template<typename _A2, typename _DiffT>
+	struct _Size<_A2, _DiffT, __void_t<typename _A2::size_type>>
+	{ using type = typename _A2::size_type; };
+
+    public:
+      /**
+       * @brief   The allocator's const pointer type.
+       *
+       * @c Alloc::const_pointer if that type exists, otherwise
+       * <tt> pointer_traits<pointer>::rebind<const value_type> </tt>
+      */
+      using const_pointer = typename _Ptr<__c_pointer, const value_type>::type;
+
+      /**
+       * @brief   The allocator's void pointer type.
+       *
+       * @c Alloc::void_pointer if that type exists, otherwise
+       * <tt> pointer_traits<pointer>::rebind<void> </tt>
+      */
+      using void_pointer = typename _Ptr<__v_pointer, void>::type;
+
+      /**
+       * @brief   The allocator's const void pointer type.
+       *
+       * @c Alloc::const_void_pointer if that type exists, otherwise
+       * <tt> pointer_traits<pointer>::rebind<const void> </tt>
+      */
+      using const_void_pointer = typename _Ptr<__cv_pointer, const void>::type;
+
+      /**
+       * @brief   The allocator's difference type
+       *
+       * @c Alloc::difference_type if that type exists, otherwise
+       * <tt> pointer_traits<pointer>::difference_type </tt>
+      */
+      using difference_type = typename _Diff<_Alloc, pointer>::type;
+
+      /**
+       * @brief   The allocator's size type
+       *
+       * @c Alloc::size_type if that type exists, otherwise
+       * <tt> make_unsigned<difference_type>::type </tt>
+      */
+      using size_type = typename _Size<_Alloc, difference_type>::type;
+
+      /**
+       * @brief   How the allocator is propagated on copy assignment
+       *
+       * @c Alloc::propagate_on_container_copy_assignment if that type exists,
+       * otherwise @c false_type
+      */
+      using propagate_on_container_copy_assignment
+	= __detected_or_t<false_type, __pocca, _Alloc>;
+
+      /**
+       * @brief   How the allocator is propagated on move assignment
+       *
+       * @c Alloc::propagate_on_container_move_assignment if that type exists,
+       * otherwise @c false_type
+      */
+      using propagate_on_container_move_assignment
+	= __detected_or_t<false_type, __pocma, _Alloc>;
+
+      /**
+       * @brief   How the allocator is propagated on swap
+       *
+       * @c Alloc::propagate_on_container_swap if that type exists,
+       * otherwise @c false_type
+      */
+      using propagate_on_container_swap
+	= __detected_or_t<false_type, __pocs, _Alloc>;
+
+      /**
+       * @brief   Whether all instances of the allocator type compare equal.
+       *
+       * @c Alloc::is_always_equal if that type exists,
+       * otherwise @c is_empty<Alloc>::type
+      */
+      using is_always_equal
+	= __detected_or_t<typename is_empty<_Alloc>::type, __equal, _Alloc>;
+
+      template<typename _Tp>
+	using rebind_alloc = __alloc_rebind<_Alloc, _Tp>;
+      template<typename _Tp>
+	using rebind_traits = allocator_traits<rebind_alloc<_Tp>>;
+
+    private:
+      template<typename _Alloc2>
+	static constexpr auto
+	_S_allocate(_Alloc2& __a, size_type __n, const_void_pointer __hint, int)
+	-> decltype(__a.allocate(__n, __hint))
+	{ return __a.allocate(__n, __hint); }
+
+      template<typename _Alloc2>
+	static constexpr pointer
+	_S_allocate(_Alloc2& __a, size_type __n, const_void_pointer, ...)
+	{ return __a.allocate(__n); }
+
+      template<typename _Tp, typename... _Args>
+	struct __construct_helper
+	{
+	  template<typename _Alloc2,
+	    typename = decltype(std::declval<_Alloc2*>()->construct(
+		  std::declval<_Tp*>(), std::declval<_Args>()...))>
+	    static true_type __test(int);
+
+	  template<typename>
+	    static false_type __test(...);
+
+	  using type = decltype(__test<_Alloc>(0));
+	};
+
+      template<typename _Tp, typename... _Args>
+	using __has_construct
+	  = typename __construct_helper<_Tp, _Args...>::type;
+
+      template<typename _Tp, typename... _Args>
+	static _GLIBCXX14_CONSTEXPR _Require<__has_construct<_Tp, _Args...>>
+	_S_construct(_Alloc& __a, _Tp* __p, _Args&&... __args)
+	noexcept(noexcept(__a.construct(__p, std::forward<_Args>(__args)...)))
+	{ __a.construct(__p, std::forward<_Args>(__args)...); }
+
+      template<typename _Tp, typename... _Args>
+	static _GLIBCXX14_CONSTEXPR
+	_Require<__and_<__not_<__has_construct<_Tp, _Args...>>,
+			       is_constructible<_Tp, _Args...>>>
+	_S_construct(_Alloc&, _Tp* __p, _Args&&... __args)
+	noexcept(std::is_nothrow_constructible<_Tp, _Args...>::value)
+	{
+#if __cplusplus <= 201703L
+	  ::new((void*)__p) _Tp(std::forward<_Args>(__args)...);
+#else
+	  std::construct_at(__p, std::forward<_Args>(__args)...);
+#endif
+	}
+
+      template<typename _Alloc2, typename _Tp>
+	static _GLIBCXX14_CONSTEXPR auto
+	_S_destroy(_Alloc2& __a, _Tp* __p, int)
+	noexcept(noexcept(__a.destroy(__p)))
+	-> decltype(__a.destroy(__p))
+	{ __a.destroy(__p); }
+
+      template<typename _Alloc2, typename _Tp>
+	static _GLIBCXX14_CONSTEXPR void
+	_S_destroy(_Alloc2&, _Tp* __p, ...)
+	noexcept(std::is_nothrow_destructible<_Tp>::value)
+	{ std::_Destroy(__p); }
+
+      template<typename _Alloc2>
+	static constexpr auto
+	_S_max_size(_Alloc2& __a, int)
+	-> decltype(__a.max_size())
+	{ return __a.max_size(); }
+
+      template<typename _Alloc2>
+	static constexpr size_type
+	_S_max_size(_Alloc2&, ...)
+	{
+	  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+	  // 2466. allocator_traits::max_size() default behavior is incorrect
+	  return __gnu_cxx::__numeric_traits<size_type>::__max
+	    / sizeof(value_type);
+	}
+
+      template<typename _Alloc2>
+	static constexpr auto
+	_S_select(_Alloc2& __a, int)
+	-> decltype(__a.select_on_container_copy_construction())
+	{ return __a.select_on_container_copy_construction(); }
+
+      template<typename _Alloc2>
+	static constexpr _Alloc2
+	_S_select(_Alloc2& __a, ...)
+	{ return __a; }
+
+    public:
+
+      /**
+       *  @brief  Allocate memory.
+       *  @param  __a  An allocator.
+       *  @param  __n  The number of objects to allocate space for.
+       *
+       *  Calls @c a.allocate(n)
+      */
+      _GLIBCXX_NODISCARD static _GLIBCXX20_CONSTEXPR pointer
+      allocate(_Alloc& __a, size_type __n)
+      { return __a.allocate(__n); }
+
+      /**
+       *  @brief  Allocate memory.
+       *  @param  __a  An allocator.
+       *  @param  __n  The number of objects to allocate space for.
+       *  @param  __hint Aid to locality.
+       *  @return Memory of suitable size and alignment for @a n objects
+       *          of type @c value_type
+       *
+       *  Returns <tt> a.allocate(n, hint) </tt> if that expression is
+       *  well-formed, otherwise returns @c a.allocate(n)
+      */
+      _GLIBCXX_NODISCARD static _GLIBCXX20_CONSTEXPR pointer
+      allocate(_Alloc& __a, size_type __n, const_void_pointer __hint)
+      { return _S_allocate(__a, __n, __hint, 0); }
+
+      /**
+       *  @brief  Deallocate memory.
+       *  @param  __a  An allocator.
+       *  @param  __p  Pointer to the memory to deallocate.
+       *  @param  __n  The number of objects space was allocated for.
+       *
+       *  Calls <tt> a.deallocate(p, n) </tt>
+      */
+      static _GLIBCXX20_CONSTEXPR void
+      deallocate(_Alloc& __a, pointer __p, size_type __n)
+      { __a.deallocate(__p, __n); }
+
+      /**
+       *  @brief  Construct an object of type `_Tp`
+       *  @param  __a  An allocator.
+       *  @param  __p  Pointer to memory of suitable size and alignment for Tp
+       *  @param  __args Constructor arguments.
+       *
+       *  Calls <tt> __a.construct(__p, std::forward<Args>(__args)...) </tt>
+       *  if that expression is well-formed, otherwise uses placement-new
+       *  to construct an object of type @a _Tp at location @a __p from the
+       *  arguments @a __args...
+      */
+      template<typename _Tp, typename... _Args>
+	static _GLIBCXX20_CONSTEXPR auto
+	construct(_Alloc& __a, _Tp* __p, _Args&&... __args)
+	noexcept(noexcept(_S_construct(__a, __p,
+				       std::forward<_Args>(__args)...)))
+	-> decltype(_S_construct(__a, __p, std::forward<_Args>(__args)...))
+	{ _S_construct(__a, __p, std::forward<_Args>(__args)...); }
+
+      /**
+       *  @brief  Destroy an object of type @a _Tp
+       *  @param  __a  An allocator.
+       *  @param  __p  Pointer to the object to destroy
+       *
+       *  Calls @c __a.destroy(__p) if that expression is well-formed,
+       *  otherwise calls @c __p->~_Tp()
+      */
+      template<typename _Tp>
+	static _GLIBCXX20_CONSTEXPR void
+	destroy(_Alloc& __a, _Tp* __p)
+	noexcept(noexcept(_S_destroy(__a, __p, 0)))
+	{ _S_destroy(__a, __p, 0); }
+
+      /**
+       *  @brief  The maximum supported allocation size
+       *  @param  __a  An allocator.
+       *  @return @c __a.max_size() or @c numeric_limits<size_type>::max()
+       *
+       *  Returns @c __a.max_size() if that expression is well-formed,
+       *  otherwise returns @c numeric_limits<size_type>::max()
+      */
+      static _GLIBCXX20_CONSTEXPR size_type
+      max_size(const _Alloc& __a) noexcept
+      { return _S_max_size(__a, 0); }
+
+      /**
+       *  @brief  Obtain an allocator to use when copying a container.
+       *  @param  __rhs  An allocator.
+       *  @return @c __rhs.select_on_container_copy_construction() or @a __rhs
+       *
+       *  Returns @c __rhs.select_on_container_copy_construction() if that
+       *  expression is well-formed, otherwise returns @a __rhs
+      */
+      static _GLIBCXX20_CONSTEXPR _Alloc
+      select_on_container_copy_construction(const _Alloc& __rhs)
+      { return _S_select(__rhs, 0); }
+    };
+
+#if __cplusplus > 201703L
+# define __cpp_lib_constexpr_dynamic_alloc 201907L
+#endif
+
+  /// Partial specialization for std::allocator.
+  template<typename _Tp>
+    struct allocator_traits<allocator<_Tp>>
+    {
+      /// The allocator type
+      using allocator_type = allocator<_Tp>;
+
+      /// The allocated type
+      using value_type = _Tp;
+
+      /// The allocator's pointer type.
+      using pointer = _Tp*;
+
+      /// The allocator's const pointer type.
+      using const_pointer = const _Tp*;
+
+      /// The allocator's void pointer type.
+      using void_pointer = void*;
+
+      /// The allocator's const void pointer type.
+      using const_void_pointer = const void*;
+
+      /// The allocator's difference type
+      using difference_type = std::ptrdiff_t;
+
+      /// The allocator's size type
+      using size_type = std::size_t;
+
+      /// How the allocator is propagated on copy assignment
+      using propagate_on_container_copy_assignment = false_type;
+
+      /// How the allocator is propagated on move assignment
+      using propagate_on_container_move_assignment = true_type;
+
+      /// How the allocator is propagated on swap
+      using propagate_on_container_swap = false_type;
+
+      /// Whether all instances of the allocator type compare equal.
+      using is_always_equal = true_type;
+
+      template<typename _Up>
+	using rebind_alloc = allocator<_Up>;
+
+      template<typename _Up>
+	using rebind_traits = allocator_traits<allocator<_Up>>;
+
+      /**
+       *  @brief  Allocate memory.
+       *  @param  __a  An allocator.
+       *  @param  __n  The number of objects to allocate space for.
+       *
+       *  Calls @c a.allocate(n)
+      */
+      _GLIBCXX_NODISCARD static _GLIBCXX20_CONSTEXPR pointer
+      allocate(allocator_type& __a, size_type __n)
+      { return __a.allocate(__n); }
+
+      /**
+       *  @brief  Allocate memory.
+       *  @param  __a  An allocator.
+       *  @param  __n  The number of objects to allocate space for.
+       *  @param  __hint Aid to locality.
+       *  @return Memory of suitable size and alignment for @a n objects
+       *          of type @c value_type
+       *
+       *  Returns <tt> a.allocate(n, hint) </tt>
+      */
+      _GLIBCXX_NODISCARD static _GLIBCXX20_CONSTEXPR pointer
+      allocate(allocator_type& __a, size_type __n, const_void_pointer __hint)
+      {
+#if __cplusplus <= 201703L
+	return __a.allocate(__n, __hint);
+#else
+	return __a.allocate(__n);
+#endif
+      }
+
+      /**
+       *  @brief  Deallocate memory.
+       *  @param  __a  An allocator.
+       *  @param  __p  Pointer to the memory to deallocate.
+       *  @param  __n  The number of objects space was allocated for.
+       *
+       *  Calls <tt> a.deallocate(p, n) </tt>
+      */
+      static _GLIBCXX20_CONSTEXPR void
+      deallocate(allocator_type& __a, pointer __p, size_type __n)
+      { __a.deallocate(__p, __n); }
+
+      /**
+       *  @brief  Construct an object of type `_Up`
+       *  @param  __a  An allocator.
+       *  @param  __p  Pointer to memory of suitable size and alignment for
+       *	       an object of type `_Up`.
+       *  @param  __args Constructor arguments.
+       *
+       *  Calls `__a.construct(__p, std::forward<_Args>(__args)...)`
+       *  in C++11, C++14 and C++17. Changed in C++20 to call
+       *  `std::construct_at(__p, std::forward<_Args>(__args)...)` instead.
+      */
+      template<typename _Up, typename... _Args>
+	static _GLIBCXX20_CONSTEXPR void
+	construct(allocator_type& __a __attribute__((__unused__)), _Up* __p,
+		  _Args&&... __args)
+	noexcept(std::is_nothrow_constructible<_Up, _Args...>::value)
+	{
+#if __cplusplus <= 201703L
+	  __a.construct(__p, std::forward<_Args>(__args)...);
+#else
+	  std::construct_at(__p, std::forward<_Args>(__args)...);
+#endif
+	}
+
+      /**
+       *  @brief  Destroy an object of type @a _Up
+       *  @param  __a  An allocator.
+       *  @param  __p  Pointer to the object to destroy
+       *
+       *  Calls @c __a.destroy(__p).
+      */
+      template<typename _Up>
+	static _GLIBCXX20_CONSTEXPR void
+	destroy(allocator_type& __a __attribute__((__unused__)), _Up* __p)
+	noexcept(is_nothrow_destructible<_Up>::value)
+	{
+#if __cplusplus <= 201703L
+	  __a.destroy(__p);
+#else
+	  std::destroy_at(__p);
+#endif
+	}
+
+      /**
+       *  @brief  The maximum supported allocation size
+       *  @param  __a  An allocator.
+       *  @return @c __a.max_size()
+      */
+      static _GLIBCXX20_CONSTEXPR size_type
+      max_size(const allocator_type& __a __attribute__((__unused__))) noexcept
+      {
+#if __cplusplus <= 201703L
+	return __a.max_size();
+#else
+	return size_t(-1) / sizeof(value_type);
+#endif
+      }
+
+      /**
+       *  @brief  Obtain an allocator to use when copying a container.
+       *  @param  __rhs  An allocator.
+       *  @return @c __rhs
+      */
+      static _GLIBCXX20_CONSTEXPR allocator_type
+      select_on_container_copy_construction(const allocator_type& __rhs)
+      { return __rhs; }
+    };
+
+  /// Explicit specialization for std::allocator<void>.
+  template<>
+    struct allocator_traits<allocator<void>>
+    {
+      /// The allocator type
+      using allocator_type = allocator<void>;
+
+      /// The allocated type
+      using value_type = void;
+
+      /// The allocator's pointer type.
+      using pointer = void*;
+
+      /// The allocator's const pointer type.
+      using const_pointer = const void*;
+
+      /// The allocator's void pointer type.
+      using void_pointer = void*;
+
+      /// The allocator's const void pointer type.
+      using const_void_pointer = const void*;
+
+      /// The allocator's difference type
+      using difference_type = std::ptrdiff_t;
+
+      /// The allocator's size type
+      using size_type = std::size_t;
+
+      /// How the allocator is propagated on copy assignment
+      using propagate_on_container_copy_assignment = false_type;
+
+      /// How the allocator is propagated on move assignment
+      using propagate_on_container_move_assignment = true_type;
+
+      /// How the allocator is propagated on swap
+      using propagate_on_container_swap = false_type;
+
+      /// Whether all instances of the allocator type compare equal.
+      using is_always_equal = true_type;
+
+      template<typename _Up>
+	using rebind_alloc = allocator<_Up>;
+
+      template<typename _Up>
+	using rebind_traits = allocator_traits<allocator<_Up>>;
+
+      /// allocate is ill-formed for allocator<void>
+      static void*
+      allocate(allocator_type&, size_type, const void* = nullptr) = delete;
+
+      /// deallocate is ill-formed for allocator<void>
+      static void
+      deallocate(allocator_type&, void*, size_type) = delete;
+
+      /**
+       *  @brief  Construct an object of type `_Up`
+       *  @param  __a  An allocator.
+       *  @param  __p  Pointer to memory of suitable size and alignment for
+       *	       an object of type `_Up`.
+       *  @param  __args Constructor arguments.
+       *
+       *  Calls `__a.construct(__p, std::forward<_Args>(__args)...)`
+       *  in C++11, C++14 and C++17. Changed in C++20 to call
+       *  `std::construct_at(__p, std::forward<_Args>(__args)...)` instead.
+      */
+      template<typename _Up, typename... _Args>
+	static _GLIBCXX20_CONSTEXPR void
+	construct(allocator_type&, _Up* __p, _Args&&... __args)
+	noexcept(std::is_nothrow_constructible<_Up, _Args...>::value)
+	{ std::_Construct(__p, std::forward<_Args>(__args)...); }
+
+      /**
+       *  @brief  Destroy an object of type `_Up`
+       *  @param  __a  An allocator.
+       *  @param  __p  Pointer to the object to destroy
+       *
+       *  Invokes the destructor for `*__p`.
+      */
+      template<typename _Up>
+	static _GLIBCXX20_CONSTEXPR void
+	destroy(allocator_type&, _Up* __p)
+	noexcept(is_nothrow_destructible<_Up>::value)
+	{ std::_Destroy(__p); }
+
+      /// max_size is ill-formed for allocator<void>
+      static size_type
+      max_size(const allocator_type&) = delete;
+
+      /**
+       *  @brief  Obtain an allocator to use when copying a container.
+       *  @param  __rhs  An allocator.
+       *  @return `__rhs`
+      */
+      static _GLIBCXX20_CONSTEXPR allocator_type
+      select_on_container_copy_construction(const allocator_type& __rhs)
+      { return __rhs; }
+    };
+
+#if __cplusplus < 201703L
+  template<typename _Alloc>
+    inline void
+    __do_alloc_on_copy(_Alloc& __one, const _Alloc& __two, true_type)
+    { __one = __two; }
+
+  template<typename _Alloc>
+    inline void
+    __do_alloc_on_copy(_Alloc&, const _Alloc&, false_type)
+    { }
+#endif
+
+  template<typename _Alloc>
+    _GLIBCXX14_CONSTEXPR inline void
+    __alloc_on_copy(_Alloc& __one, const _Alloc& __two)
+    {
+      typedef allocator_traits<_Alloc> __traits;
+      typedef typename __traits::propagate_on_container_copy_assignment __pocca;
+#if __cplusplus >= 201703L
+      if constexpr (__pocca::value)
+	__one = __two;
+#else
+      __do_alloc_on_copy(__one, __two, __pocca());
+#endif
+    }
+
+  template<typename _Alloc>
+    constexpr _Alloc
+    __alloc_on_copy(const _Alloc& __a)
+    {
+      typedef allocator_traits<_Alloc> __traits;
+      return __traits::select_on_container_copy_construction(__a);
+    }
+
+#if __cplusplus < 201703L
+  template<typename _Alloc>
+    inline void __do_alloc_on_move(_Alloc& __one, _Alloc& __two, true_type)
+    { __one = std::move(__two); }
+
+  template<typename _Alloc>
+    inline void __do_alloc_on_move(_Alloc&, _Alloc&, false_type)
+    { }
+#endif
+
+  template<typename _Alloc>
+    _GLIBCXX14_CONSTEXPR inline void
+    __alloc_on_move(_Alloc& __one, _Alloc& __two)
+    {
+      typedef allocator_traits<_Alloc> __traits;
+      typedef typename __traits::propagate_on_container_move_assignment __pocma;
+#if __cplusplus >= 201703L
+      if constexpr (__pocma::value)
+	__one = std::move(__two);
+#else
+      __do_alloc_on_move(__one, __two, __pocma());
+#endif
+    }
+
+#if __cplusplus < 201703L
+  template<typename _Alloc>
+    inline void __do_alloc_on_swap(_Alloc& __one, _Alloc& __two, true_type)
+    {
+      using std::swap;
+      swap(__one, __two);
+    }
+
+  template<typename _Alloc>
+    inline void __do_alloc_on_swap(_Alloc&, _Alloc&, false_type)
+    { }
+#endif
+
+  template<typename _Alloc>
+    _GLIBCXX14_CONSTEXPR inline void
+    __alloc_on_swap(_Alloc& __one, _Alloc& __two)
+    {
+      typedef allocator_traits<_Alloc> __traits;
+      typedef typename __traits::propagate_on_container_swap __pocs;
+#if __cplusplus >= 201703L
+      if constexpr (__pocs::value)
+	{
+	  using std::swap;
+	  swap(__one, __two);
+	}
+#else
+      __do_alloc_on_swap(__one, __two, __pocs());
+#endif
+    }
+
+  template<typename _Alloc, typename _Tp,
+	   typename _ValueT = __remove_cvref_t<typename _Alloc::value_type>,
+	   typename = void>
+    struct __is_alloc_insertable_impl
+    : false_type
+    { };
+
+  template<typename _Alloc, typename _Tp, typename _ValueT>
+    struct __is_alloc_insertable_impl<_Alloc, _Tp, _ValueT,
+      __void_t<decltype(allocator_traits<_Alloc>::construct(
+		   std::declval<_Alloc&>(), std::declval<_ValueT*>(),
+		   std::declval<_Tp>()))>>
+    : true_type
+    { };
+
+  // true if _Alloc::value_type is CopyInsertable into containers using _Alloc
+  // (might be wrong if _Alloc::construct exists but is not constrained,
+  // i.e. actually trying to use it would still be invalid. Use with caution.)
+  template<typename _Alloc>
+    struct __is_copy_insertable
+    : __is_alloc_insertable_impl<_Alloc,
+				 typename _Alloc::value_type const&>::type
+    { };
+
+  // std::allocator<_Tp> just requires CopyConstructible
+  template<typename _Tp>
+    struct __is_copy_insertable<allocator<_Tp>>
+    : is_copy_constructible<_Tp>
+    { };
+
+  // true if _Alloc::value_type is MoveInsertable into containers using _Alloc
+  // (might be wrong if _Alloc::construct exists but is not constrained,
+  // i.e. actually trying to use it would still be invalid. Use with caution.)
+  template<typename _Alloc>
+    struct __is_move_insertable
+    : __is_alloc_insertable_impl<_Alloc, typename _Alloc::value_type>::type
+    { };
+
+  // std::allocator<_Tp> just requires MoveConstructible
+  template<typename _Tp>
+    struct __is_move_insertable<allocator<_Tp>>
+    : is_move_constructible<_Tp>
+    { };
+
+  // Trait to detect Allocator-like types.
+  template<typename _Alloc, typename = void>
+    struct __is_allocator : false_type { };
+
+  template<typename _Alloc>
+    struct __is_allocator<_Alloc,
+      __void_t<typename _Alloc::value_type,
+	       decltype(std::declval<_Alloc&>().allocate(size_t{}))>>
+    : true_type { };
+
+  template<typename _Alloc>
+    using _RequireAllocator
+      = typename enable_if<__is_allocator<_Alloc>::value, _Alloc>::type;
+
+  template<typename _Alloc>
+    using _RequireNotAllocator
+      = typename enable_if<!__is_allocator<_Alloc>::value, _Alloc>::type;
+
+#if __cpp_concepts >= 201907L
+  template<typename _Alloc>
+    concept __allocator_like = requires (_Alloc& __a) {
+      typename _Alloc::value_type;
+      __a.deallocate(__a.allocate(1u), 1u);
+    };
+#endif
+#endif // C++11
+
+  /**
+   * Destroy a range of objects using the supplied allocator.  For
+   * non-default allocators we do not optimize away invocation of
+   * destroy() even if _Tp has a trivial destructor.
+   */
+
+  template<typename _ForwardIterator, typename _Allocator>
+    _GLIBCXX20_CONSTEXPR
+    void
+    _Destroy(_ForwardIterator __first, _ForwardIterator __last,
+	     _Allocator& __alloc)
+    {
+      for (; __first != __last; ++__first)
+#if __cplusplus < 201103L
+	__alloc.destroy(std::__addressof(*__first));
+#else
+	allocator_traits<_Allocator>::destroy(__alloc,
+					      std::__addressof(*__first));
+#endif
+    }
+
+  template<typename _ForwardIterator, typename _Tp>
+    _GLIBCXX20_CONSTEXPR
+    inline void
+    _Destroy(_ForwardIterator __first, _ForwardIterator __last,
+	     allocator<_Tp>&)
+    {
+      _Destroy(__first, __last);
+    }
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+#endif // _ALLOC_TRAITS_H
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@@ -0,0 +1,106 @@
+// Guarded Allocation -*- C++ -*-
+
+// Copyright (C) 2014-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/allocated_ptr.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{memory}
+ */
+
+#ifndef _ALLOCATED_PTR_H
+#define _ALLOCATED_PTR_H 1
+
+#if __cplusplus < 201103L
+# include <bits/c++0xwarning.h>
+#else
+# include <type_traits>
+# include <bits/ptr_traits.h>
+# include <bits/alloc_traits.h>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+/// @cond undocumented
+
+  /// Non-standard RAII type for managing pointers obtained from allocators.
+  template<typename _Alloc>
+    struct __allocated_ptr
+    {
+      using pointer = typename allocator_traits<_Alloc>::pointer;
+      using value_type = typename allocator_traits<_Alloc>::value_type;
+
+      /// Take ownership of __ptr
+      __allocated_ptr(_Alloc& __a, pointer __ptr) noexcept
+      : _M_alloc(std::__addressof(__a)), _M_ptr(__ptr)
+      { }
+
+      /// Convert __ptr to allocator's pointer type and take ownership of it
+      template<typename _Ptr,
+	       typename _Req = _Require<is_same<_Ptr, value_type*>>>
+      __allocated_ptr(_Alloc& __a, _Ptr __ptr)
+      : _M_alloc(std::__addressof(__a)),
+	_M_ptr(pointer_traits<pointer>::pointer_to(*__ptr))
+      { }
+
+      /// Transfer ownership of the owned pointer
+      __allocated_ptr(__allocated_ptr&& __gd) noexcept
+      : _M_alloc(__gd._M_alloc), _M_ptr(__gd._M_ptr)
+      { __gd._M_ptr = nullptr; }
+
+      /// Deallocate the owned pointer
+      ~__allocated_ptr()
+      {
+	if (_M_ptr != nullptr)
+	  std::allocator_traits<_Alloc>::deallocate(*_M_alloc, _M_ptr, 1);
+      }
+
+      /// Release ownership of the owned pointer
+      __allocated_ptr&
+      operator=(std::nullptr_t) noexcept
+      {
+	_M_ptr = nullptr;
+	return *this;
+      }
+
+      /// Get the address that the owned pointer refers to.
+      value_type* get() { return std::__to_address(_M_ptr); }
+
+    private:
+      _Alloc* _M_alloc;
+      pointer _M_ptr;
+    };
+
+  /// Allocate space for a single object using __a
+  template<typename _Alloc>
+    __allocated_ptr<_Alloc>
+    __allocate_guarded(_Alloc& __a)
+    {
+      return { __a, std::allocator_traits<_Alloc>::allocate(__a, 1) };
+    }
+
+/// @endcond
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif
+#endif
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@@ -0,0 +1,337 @@
+// Allocators -*- C++ -*-
+
+// Copyright (C) 2001-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/*
+ * Copyright (c) 1996-1997
+ * Silicon Graphics Computer Systems, Inc.
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Silicon Graphics makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ */
+
+/** @file bits/allocator.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{memory}
+ */
+
+#ifndef _ALLOCATOR_H
+#define _ALLOCATOR_H 1
+
+#include <bits/c++allocator.h> // Define the base class to std::allocator.
+#include <bits/memoryfwd.h>
+#if __cplusplus >= 201103L
+#include <type_traits>
+#endif
+
+#define __cpp_lib_incomplete_container_elements 201505L
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /**
+   *  @addtogroup allocators
+   *  @{
+   */
+
+  // Since C++20 the primary template should be used for allocator<void>,
+  // but then it would have a non-trivial default ctor and dtor for C++20,
+  // but trivial for C++98-17, which would be an ABI incompatibiliy between
+  // different standard dialects. So C++20 still uses the allocator<void>
+  // explicit specialization, with the historical ABI properties, but with
+  // the same members that are present in the primary template.
+
+  /// allocator<void> specialization.
+  template<>
+    class allocator<void>
+    {
+    public:
+      typedef void        value_type;
+      typedef size_t      size_type;
+      typedef ptrdiff_t   difference_type;
+
+#if __cplusplus <= 201703L
+      // These were removed for C++20, allocator_traits does the right thing.
+      typedef void*       pointer;
+      typedef const void* const_pointer;
+
+      template<typename _Tp1>
+	struct rebind
+	{ typedef allocator<_Tp1> other; };
+#endif
+
+#if __cplusplus >= 201103L
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 2103. std::allocator propagate_on_container_move_assignment
+      using propagate_on_container_move_assignment = true_type;
+
+      using is_always_equal
+	_GLIBCXX20_DEPRECATED_SUGGEST("std::allocator_traits::is_always_equal")
+	= true_type;
+
+#if __cplusplus >= 202002L
+      // As noted above, these members are present for C++20 to provide the
+      // same API as the primary template, but still trivial as in pre-C++20.
+      allocator() = default;
+      ~allocator() = default;
+
+      template<typename _Up>
+	constexpr
+	allocator(const allocator<_Up>&) noexcept { }
+
+      // No allocate member because it's ill-formed by LWG 3307.
+      // No deallocate member because it would be undefined to call it
+      // with any pointer which wasn't obtained from allocate.
+#endif // C++20
+#endif // C++11
+    };
+
+  /**
+   * @brief  The @a standard allocator, as per C++03 [20.4.1].
+   *
+   *  See https://gcc.gnu.org/onlinedocs/libstdc++/manual/memory.html#std.util.memory.allocator
+   *  for further details.
+   *
+   *  @tparam  _Tp  Type of allocated object.
+   */
+  template<typename _Tp>
+    class allocator : public __allocator_base<_Tp>
+    {
+    public:
+      typedef _Tp        value_type;
+      typedef size_t     size_type;
+      typedef ptrdiff_t  difference_type;
+
+#if __cplusplus <= 201703L
+      // These were removed for C++20.
+      typedef _Tp*       pointer;
+      typedef const _Tp* const_pointer;
+      typedef _Tp&       reference;
+      typedef const _Tp& const_reference;
+
+      template<typename _Tp1>
+	struct rebind
+	{ typedef allocator<_Tp1> other; };
+#endif
+
+#if __cplusplus >= 201103L
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 2103. std::allocator propagate_on_container_move_assignment
+      using propagate_on_container_move_assignment = true_type;
+
+      using is_always_equal
+	_GLIBCXX20_DEPRECATED_SUGGEST("std::allocator_traits::is_always_equal")
+	= true_type;
+#endif
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 3035. std::allocator's constructors should be constexpr
+      _GLIBCXX20_CONSTEXPR
+      allocator() _GLIBCXX_NOTHROW { }
+
+      _GLIBCXX20_CONSTEXPR
+      allocator(const allocator& __a) _GLIBCXX_NOTHROW
+      : __allocator_base<_Tp>(__a) { }
+
+#if __cplusplus >= 201103L
+      // Avoid implicit deprecation.
+      allocator& operator=(const allocator&) = default;
+#endif
+
+      template<typename _Tp1>
+	_GLIBCXX20_CONSTEXPR
+	allocator(const allocator<_Tp1>&) _GLIBCXX_NOTHROW { }
+
+#if __cpp_constexpr_dynamic_alloc
+      constexpr
+#endif
+      ~allocator() _GLIBCXX_NOTHROW { }
+
+#if __cplusplus > 201703L
+      [[nodiscard,__gnu__::__always_inline__]]
+      constexpr _Tp*
+      allocate(size_t __n)
+      {
+	if (std::__is_constant_evaluated())
+	  {
+	    if (__builtin_mul_overflow(__n, sizeof(_Tp), &__n))
+	      std::__throw_bad_array_new_length();
+	    return static_cast<_Tp*>(::operator new(__n));
+	  }
+
+	return __allocator_base<_Tp>::allocate(__n, 0);
+      }
+
+      [[__gnu__::__always_inline__]]
+      constexpr void
+      deallocate(_Tp* __p, size_t __n)
+      {
+	if (std::__is_constant_evaluated())
+	  {
+	    ::operator delete(__p);
+	    return;
+	  }
+	__allocator_base<_Tp>::deallocate(__p, __n);
+      }
+#endif // C++20
+
+      friend _GLIBCXX20_CONSTEXPR bool
+      operator==(const allocator&, const allocator&) _GLIBCXX_NOTHROW
+      { return true; }
+
+#if __cpp_impl_three_way_comparison < 201907L
+      friend _GLIBCXX20_CONSTEXPR bool
+      operator!=(const allocator&, const allocator&) _GLIBCXX_NOTHROW
+      { return false; }
+#endif
+
+      // Inherit everything else.
+    };
+
+  template<typename _T1, typename _T2>
+    inline _GLIBCXX20_CONSTEXPR bool
+    operator==(const allocator<_T1>&, const allocator<_T2>&)
+    _GLIBCXX_NOTHROW
+    { return true; }
+
+#if __cpp_impl_three_way_comparison < 201907L
+  template<typename _T1, typename _T2>
+    inline _GLIBCXX20_CONSTEXPR bool
+    operator!=(const allocator<_T1>&, const allocator<_T2>&)
+    _GLIBCXX_NOTHROW
+    { return false; }
+#endif
+
+  // Invalid allocator<cv T> partial specializations.
+  // allocator_traits::rebind_alloc can be used to form a valid allocator type.
+  template<typename _Tp>
+    class allocator<const _Tp>
+    {
+    public:
+      typedef _Tp value_type;
+      template<typename _Up> allocator(const allocator<_Up>&) { }
+    };
+
+  template<typename _Tp>
+    class allocator<volatile _Tp>
+    {
+    public:
+      typedef _Tp value_type;
+      template<typename _Up> allocator(const allocator<_Up>&) { }
+    };
+
+  template<typename _Tp>
+    class allocator<const volatile _Tp>
+    {
+    public:
+      typedef _Tp value_type;
+      template<typename _Up> allocator(const allocator<_Up>&) { }
+    };
+
+  /// @} group allocator
+
+  // Inhibit implicit instantiations for required instantiations,
+  // which are defined via explicit instantiations elsewhere.
+#if _GLIBCXX_EXTERN_TEMPLATE
+  extern template class allocator<char>;
+  extern template class allocator<wchar_t>;
+#endif
+
+  // Undefine.
+#undef __allocator_base
+
+  // To implement Option 3 of DR 431.
+  template<typename _Alloc, bool = __is_empty(_Alloc)>
+    struct __alloc_swap
+    { static void _S_do_it(_Alloc&, _Alloc&) _GLIBCXX_NOEXCEPT { } };
+
+  template<typename _Alloc>
+    struct __alloc_swap<_Alloc, false>
+    {
+      static void
+      _S_do_it(_Alloc& __one, _Alloc& __two) _GLIBCXX_NOEXCEPT
+      {
+	// Precondition: swappable allocators.
+	if (__one != __two)
+	  swap(__one, __two);
+      }
+    };
+
+  // Optimize for stateless allocators.
+  template<typename _Alloc, bool = __is_empty(_Alloc)>
+    struct __alloc_neq
+    {
+      static bool
+      _S_do_it(const _Alloc&, const _Alloc&)
+      { return false; }
+    };
+
+  template<typename _Alloc>
+    struct __alloc_neq<_Alloc, false>
+    {
+      static bool
+      _S_do_it(const _Alloc& __one, const _Alloc& __two)
+      { return __one != __two; }
+    };
+
+#if __cplusplus >= 201103L
+  template<typename _Tp, bool
+    = __or_<is_copy_constructible<typename _Tp::value_type>,
+            is_nothrow_move_constructible<typename _Tp::value_type>>::value>
+    struct __shrink_to_fit_aux
+    { static bool _S_do_it(_Tp&) noexcept { return false; } };
+
+  template<typename _Tp>
+    struct __shrink_to_fit_aux<_Tp, true>
+    {
+      _GLIBCXX20_CONSTEXPR
+      static bool
+      _S_do_it(_Tp& __c) noexcept
+      {
+#if __cpp_exceptions
+	try
+	  {
+	    _Tp(__make_move_if_noexcept_iterator(__c.begin()),
+		__make_move_if_noexcept_iterator(__c.end()),
+		__c.get_allocator()).swap(__c);
+	    return true;
+	  }
+	catch(...)
+	  { return false; }
+#else
+	return false;
+#endif
+      }
+    };
+#endif
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif
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@@ -0,0 +1,1946 @@
+// -*- C++ -*- header.
+
+// Copyright (C) 2008-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/atomic_base.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{atomic}
+ */
+
+#ifndef _GLIBCXX_ATOMIC_BASE_H
+#define _GLIBCXX_ATOMIC_BASE_H 1
+
+#pragma GCC system_header
+
+#include <bits/c++config.h>
+#include <stdint.h>
+#include <bits/atomic_lockfree_defines.h>
+#include <bits/move.h>
+
+#if __cplusplus > 201703L && _GLIBCXX_HOSTED
+#include <bits/atomic_wait.h>
+#endif
+
+#ifndef _GLIBCXX_ALWAYS_INLINE
+#define _GLIBCXX_ALWAYS_INLINE inline __attribute__((__always_inline__))
+#endif
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /**
+   * @defgroup atomics Atomics
+   *
+   * Components for performing atomic operations.
+   * @{
+   */
+
+  /// Enumeration for memory_order
+#if __cplusplus > 201703L
+  enum class memory_order : int
+    {
+      relaxed,
+      consume,
+      acquire,
+      release,
+      acq_rel,
+      seq_cst
+    };
+
+  inline constexpr memory_order memory_order_relaxed = memory_order::relaxed;
+  inline constexpr memory_order memory_order_consume = memory_order::consume;
+  inline constexpr memory_order memory_order_acquire = memory_order::acquire;
+  inline constexpr memory_order memory_order_release = memory_order::release;
+  inline constexpr memory_order memory_order_acq_rel = memory_order::acq_rel;
+  inline constexpr memory_order memory_order_seq_cst = memory_order::seq_cst;
+#else
+  typedef enum memory_order
+    {
+      memory_order_relaxed,
+      memory_order_consume,
+      memory_order_acquire,
+      memory_order_release,
+      memory_order_acq_rel,
+      memory_order_seq_cst
+    } memory_order;
+#endif
+
+  enum __memory_order_modifier
+    {
+      __memory_order_mask          = 0x0ffff,
+      __memory_order_modifier_mask = 0xffff0000,
+      __memory_order_hle_acquire   = 0x10000,
+      __memory_order_hle_release   = 0x20000
+    };
+
+  constexpr memory_order
+  operator|(memory_order __m, __memory_order_modifier __mod)
+  {
+    return memory_order(int(__m) | int(__mod));
+  }
+
+  constexpr memory_order
+  operator&(memory_order __m, __memory_order_modifier __mod)
+  {
+    return memory_order(int(__m) & int(__mod));
+  }
+
+  // Drop release ordering as per [atomics.types.operations.req]/21
+  constexpr memory_order
+  __cmpexch_failure_order2(memory_order __m) noexcept
+  {
+    return __m == memory_order_acq_rel ? memory_order_acquire
+      : __m == memory_order_release ? memory_order_relaxed : __m;
+  }
+
+  constexpr memory_order
+  __cmpexch_failure_order(memory_order __m) noexcept
+  {
+    return memory_order(__cmpexch_failure_order2(__m & __memory_order_mask)
+      | __memory_order_modifier(__m & __memory_order_modifier_mask));
+  }
+
+  constexpr bool
+  __is_valid_cmpexch_failure_order(memory_order __m) noexcept
+  {
+    return (__m & __memory_order_mask) != memory_order_release
+	&& (__m & __memory_order_mask) != memory_order_acq_rel;
+  }
+
+  _GLIBCXX_ALWAYS_INLINE void
+  atomic_thread_fence(memory_order __m) noexcept
+  { __atomic_thread_fence(int(__m)); }
+
+  _GLIBCXX_ALWAYS_INLINE void
+  atomic_signal_fence(memory_order __m) noexcept
+  { __atomic_signal_fence(int(__m)); }
+
+  /// kill_dependency
+  template<typename _Tp>
+    inline _Tp
+    kill_dependency(_Tp __y) noexcept
+    {
+      _Tp __ret(__y);
+      return __ret;
+    }
+
+  // Base types for atomics.
+  template<typename _IntTp>
+    struct __atomic_base;
+
+#if __cplusplus <= 201703L
+# define _GLIBCXX20_INIT(I)
+#else
+# define __cpp_lib_atomic_value_initialization 201911L
+# define _GLIBCXX20_INIT(I) = I
+#endif
+
+#define ATOMIC_VAR_INIT(_VI) { _VI }
+
+  template<typename _Tp>
+    struct atomic;
+
+  template<typename _Tp>
+    struct atomic<_Tp*>;
+
+    /* The target's "set" value for test-and-set may not be exactly 1.  */
+#if __GCC_ATOMIC_TEST_AND_SET_TRUEVAL == 1
+    typedef bool __atomic_flag_data_type;
+#else
+    typedef unsigned char __atomic_flag_data_type;
+#endif
+
+  /**
+   *  @brief Base type for atomic_flag.
+   *
+   *  Base type is POD with data, allowing atomic_flag to derive from
+   *  it and meet the standard layout type requirement. In addition to
+   *  compatibility with a C interface, this allows different
+   *  implementations of atomic_flag to use the same atomic operation
+   *  functions, via a standard conversion to the __atomic_flag_base
+   *  argument.
+  */
+  _GLIBCXX_BEGIN_EXTERN_C
+
+  struct __atomic_flag_base
+  {
+    __atomic_flag_data_type _M_i _GLIBCXX20_INIT({});
+  };
+
+  _GLIBCXX_END_EXTERN_C
+
+#define ATOMIC_FLAG_INIT { 0 }
+
+  /// atomic_flag
+  struct atomic_flag : public __atomic_flag_base
+  {
+    atomic_flag() noexcept = default;
+    ~atomic_flag() noexcept = default;
+    atomic_flag(const atomic_flag&) = delete;
+    atomic_flag& operator=(const atomic_flag&) = delete;
+    atomic_flag& operator=(const atomic_flag&) volatile = delete;
+
+    // Conversion to ATOMIC_FLAG_INIT.
+    constexpr atomic_flag(bool __i) noexcept
+      : __atomic_flag_base{ _S_init(__i) }
+    { }
+
+    _GLIBCXX_ALWAYS_INLINE bool
+    test_and_set(memory_order __m = memory_order_seq_cst) noexcept
+    {
+      return __atomic_test_and_set (&_M_i, int(__m));
+    }
+
+    _GLIBCXX_ALWAYS_INLINE bool
+    test_and_set(memory_order __m = memory_order_seq_cst) volatile noexcept
+    {
+      return __atomic_test_and_set (&_M_i, int(__m));
+    }
+
+#if __cplusplus > 201703L
+#define __cpp_lib_atomic_flag_test 201907L
+
+    _GLIBCXX_ALWAYS_INLINE bool
+    test(memory_order __m = memory_order_seq_cst) const noexcept
+    {
+      __atomic_flag_data_type __v;
+      __atomic_load(&_M_i, &__v, int(__m));
+      return __v == __GCC_ATOMIC_TEST_AND_SET_TRUEVAL;
+    }
+
+    _GLIBCXX_ALWAYS_INLINE bool
+    test(memory_order __m = memory_order_seq_cst) const volatile noexcept
+    {
+      __atomic_flag_data_type __v;
+      __atomic_load(&_M_i, &__v, int(__m));
+      return __v == __GCC_ATOMIC_TEST_AND_SET_TRUEVAL;
+    }
+
+#if __cpp_lib_atomic_wait
+    _GLIBCXX_ALWAYS_INLINE void
+    wait(bool __old,
+	memory_order __m = memory_order_seq_cst) const noexcept
+    {
+      const __atomic_flag_data_type __v
+	= __old ? __GCC_ATOMIC_TEST_AND_SET_TRUEVAL : 0;
+
+      std::__atomic_wait_address_v(&_M_i, __v,
+	  [__m, this] { return __atomic_load_n(&_M_i, int(__m)); });
+    }
+
+    // TODO add const volatile overload
+
+    _GLIBCXX_ALWAYS_INLINE void
+    notify_one() noexcept
+    { std::__atomic_notify_address(&_M_i, false); }
+
+    // TODO add const volatile overload
+
+    _GLIBCXX_ALWAYS_INLINE void
+    notify_all() noexcept
+    { std::__atomic_notify_address(&_M_i, true); }
+
+    // TODO add const volatile overload
+#endif // __cpp_lib_atomic_wait
+#endif // C++20
+
+    _GLIBCXX_ALWAYS_INLINE void
+    clear(memory_order __m = memory_order_seq_cst) noexcept
+    {
+      memory_order __b __attribute__ ((__unused__))
+	= __m & __memory_order_mask;
+      __glibcxx_assert(__b != memory_order_consume);
+      __glibcxx_assert(__b != memory_order_acquire);
+      __glibcxx_assert(__b != memory_order_acq_rel);
+
+      __atomic_clear (&_M_i, int(__m));
+    }
+
+    _GLIBCXX_ALWAYS_INLINE void
+    clear(memory_order __m = memory_order_seq_cst) volatile noexcept
+    {
+      memory_order __b __attribute__ ((__unused__))
+	= __m & __memory_order_mask;
+      __glibcxx_assert(__b != memory_order_consume);
+      __glibcxx_assert(__b != memory_order_acquire);
+      __glibcxx_assert(__b != memory_order_acq_rel);
+
+      __atomic_clear (&_M_i, int(__m));
+    }
+
+  private:
+    static constexpr __atomic_flag_data_type
+    _S_init(bool __i)
+    { return __i ? __GCC_ATOMIC_TEST_AND_SET_TRUEVAL : 0; }
+  };
+
+
+  /// Base class for atomic integrals.
+  //
+  // For each of the integral types, define atomic_[integral type] struct
+  //
+  // atomic_bool     bool
+  // atomic_char     char
+  // atomic_schar    signed char
+  // atomic_uchar    unsigned char
+  // atomic_short    short
+  // atomic_ushort   unsigned short
+  // atomic_int      int
+  // atomic_uint     unsigned int
+  // atomic_long     long
+  // atomic_ulong    unsigned long
+  // atomic_llong    long long
+  // atomic_ullong   unsigned long long
+  // atomic_char8_t  char8_t
+  // atomic_char16_t char16_t
+  // atomic_char32_t char32_t
+  // atomic_wchar_t  wchar_t
+  //
+  // NB: Assuming _ITp is an integral scalar type that is 1, 2, 4, or
+  // 8 bytes, since that is what GCC built-in functions for atomic
+  // memory access expect.
+  template<typename _ITp>
+    struct __atomic_base
+    {
+      using value_type = _ITp;
+      using difference_type = value_type;
+
+    private:
+      typedef _ITp 	__int_type;
+
+      static constexpr int _S_alignment =
+	sizeof(_ITp) > alignof(_ITp) ? sizeof(_ITp) : alignof(_ITp);
+
+      alignas(_S_alignment) __int_type _M_i _GLIBCXX20_INIT(0);
+
+    public:
+      __atomic_base() noexcept = default;
+      ~__atomic_base() noexcept = default;
+      __atomic_base(const __atomic_base&) = delete;
+      __atomic_base& operator=(const __atomic_base&) = delete;
+      __atomic_base& operator=(const __atomic_base&) volatile = delete;
+
+      // Requires __int_type convertible to _M_i.
+      constexpr __atomic_base(__int_type __i) noexcept : _M_i (__i) { }
+
+      operator __int_type() const noexcept
+      { return load(); }
+
+      operator __int_type() const volatile noexcept
+      { return load(); }
+
+      __int_type
+      operator=(__int_type __i) noexcept
+      {
+	store(__i);
+	return __i;
+      }
+
+      __int_type
+      operator=(__int_type __i) volatile noexcept
+      {
+	store(__i);
+	return __i;
+      }
+
+      __int_type
+      operator++(int) noexcept
+      { return fetch_add(1); }
+
+      __int_type
+      operator++(int) volatile noexcept
+      { return fetch_add(1); }
+
+      __int_type
+      operator--(int) noexcept
+      { return fetch_sub(1); }
+
+      __int_type
+      operator--(int) volatile noexcept
+      { return fetch_sub(1); }
+
+      __int_type
+      operator++() noexcept
+      { return __atomic_add_fetch(&_M_i, 1, int(memory_order_seq_cst)); }
+
+      __int_type
+      operator++() volatile noexcept
+      { return __atomic_add_fetch(&_M_i, 1, int(memory_order_seq_cst)); }
+
+      __int_type
+      operator--() noexcept
+      { return __atomic_sub_fetch(&_M_i, 1, int(memory_order_seq_cst)); }
+
+      __int_type
+      operator--() volatile noexcept
+      { return __atomic_sub_fetch(&_M_i, 1, int(memory_order_seq_cst)); }
+
+      __int_type
+      operator+=(__int_type __i) noexcept
+      { return __atomic_add_fetch(&_M_i, __i, int(memory_order_seq_cst)); }
+
+      __int_type
+      operator+=(__int_type __i) volatile noexcept
+      { return __atomic_add_fetch(&_M_i, __i, int(memory_order_seq_cst)); }
+
+      __int_type
+      operator-=(__int_type __i) noexcept
+      { return __atomic_sub_fetch(&_M_i, __i, int(memory_order_seq_cst)); }
+
+      __int_type
+      operator-=(__int_type __i) volatile noexcept
+      { return __atomic_sub_fetch(&_M_i, __i, int(memory_order_seq_cst)); }
+
+      __int_type
+      operator&=(__int_type __i) noexcept
+      { return __atomic_and_fetch(&_M_i, __i, int(memory_order_seq_cst)); }
+
+      __int_type
+      operator&=(__int_type __i) volatile noexcept
+      { return __atomic_and_fetch(&_M_i, __i, int(memory_order_seq_cst)); }
+
+      __int_type
+      operator|=(__int_type __i) noexcept
+      { return __atomic_or_fetch(&_M_i, __i, int(memory_order_seq_cst)); }
+
+      __int_type
+      operator|=(__int_type __i) volatile noexcept
+      { return __atomic_or_fetch(&_M_i, __i, int(memory_order_seq_cst)); }
+
+      __int_type
+      operator^=(__int_type __i) noexcept
+      { return __atomic_xor_fetch(&_M_i, __i, int(memory_order_seq_cst)); }
+
+      __int_type
+      operator^=(__int_type __i) volatile noexcept
+      { return __atomic_xor_fetch(&_M_i, __i, int(memory_order_seq_cst)); }
+
+      bool
+      is_lock_free() const noexcept
+      {
+	// Use a fake, minimally aligned pointer.
+	return __atomic_is_lock_free(sizeof(_M_i),
+	    reinterpret_cast<void *>(-_S_alignment));
+      }
+
+      bool
+      is_lock_free() const volatile noexcept
+      {
+	// Use a fake, minimally aligned pointer.
+	return __atomic_is_lock_free(sizeof(_M_i),
+	    reinterpret_cast<void *>(-_S_alignment));
+      }
+
+      _GLIBCXX_ALWAYS_INLINE void
+      store(__int_type __i, memory_order __m = memory_order_seq_cst) noexcept
+      {
+	memory_order __b __attribute__ ((__unused__))
+	  = __m & __memory_order_mask;
+	__glibcxx_assert(__b != memory_order_acquire);
+	__glibcxx_assert(__b != memory_order_acq_rel);
+	__glibcxx_assert(__b != memory_order_consume);
+
+	__atomic_store_n(&_M_i, __i, int(__m));
+      }
+
+      _GLIBCXX_ALWAYS_INLINE void
+      store(__int_type __i,
+	    memory_order __m = memory_order_seq_cst) volatile noexcept
+      {
+	memory_order __b __attribute__ ((__unused__))
+	  = __m & __memory_order_mask;
+	__glibcxx_assert(__b != memory_order_acquire);
+	__glibcxx_assert(__b != memory_order_acq_rel);
+	__glibcxx_assert(__b != memory_order_consume);
+
+	__atomic_store_n(&_M_i, __i, int(__m));
+      }
+
+      _GLIBCXX_ALWAYS_INLINE __int_type
+      load(memory_order __m = memory_order_seq_cst) const noexcept
+      {
+	memory_order __b __attribute__ ((__unused__))
+	  = __m & __memory_order_mask;
+	__glibcxx_assert(__b != memory_order_release);
+	__glibcxx_assert(__b != memory_order_acq_rel);
+
+	return __atomic_load_n(&_M_i, int(__m));
+      }
+
+      _GLIBCXX_ALWAYS_INLINE __int_type
+      load(memory_order __m = memory_order_seq_cst) const volatile noexcept
+      {
+	memory_order __b __attribute__ ((__unused__))
+	  = __m & __memory_order_mask;
+	__glibcxx_assert(__b != memory_order_release);
+	__glibcxx_assert(__b != memory_order_acq_rel);
+
+	return __atomic_load_n(&_M_i, int(__m));
+      }
+
+      _GLIBCXX_ALWAYS_INLINE __int_type
+      exchange(__int_type __i,
+	       memory_order __m = memory_order_seq_cst) noexcept
+      {
+	return __atomic_exchange_n(&_M_i, __i, int(__m));
+      }
+
+
+      _GLIBCXX_ALWAYS_INLINE __int_type
+      exchange(__int_type __i,
+	       memory_order __m = memory_order_seq_cst) volatile noexcept
+      {
+	return __atomic_exchange_n(&_M_i, __i, int(__m));
+      }
+
+      _GLIBCXX_ALWAYS_INLINE bool
+      compare_exchange_weak(__int_type& __i1, __int_type __i2,
+			    memory_order __m1, memory_order __m2) noexcept
+      {
+	__glibcxx_assert(__is_valid_cmpexch_failure_order(__m2));
+
+	return __atomic_compare_exchange_n(&_M_i, &__i1, __i2, 1,
+					   int(__m1), int(__m2));
+      }
+
+      _GLIBCXX_ALWAYS_INLINE bool
+      compare_exchange_weak(__int_type& __i1, __int_type __i2,
+			    memory_order __m1,
+			    memory_order __m2) volatile noexcept
+      {
+	__glibcxx_assert(__is_valid_cmpexch_failure_order(__m2));
+
+	return __atomic_compare_exchange_n(&_M_i, &__i1, __i2, 1,
+					   int(__m1), int(__m2));
+      }
+
+      _GLIBCXX_ALWAYS_INLINE bool
+      compare_exchange_weak(__int_type& __i1, __int_type __i2,
+			    memory_order __m = memory_order_seq_cst) noexcept
+      {
+	return compare_exchange_weak(__i1, __i2, __m,
+				     __cmpexch_failure_order(__m));
+      }
+
+      _GLIBCXX_ALWAYS_INLINE bool
+      compare_exchange_weak(__int_type& __i1, __int_type __i2,
+		   memory_order __m = memory_order_seq_cst) volatile noexcept
+      {
+	return compare_exchange_weak(__i1, __i2, __m,
+				     __cmpexch_failure_order(__m));
+      }
+
+      _GLIBCXX_ALWAYS_INLINE bool
+      compare_exchange_strong(__int_type& __i1, __int_type __i2,
+			      memory_order __m1, memory_order __m2) noexcept
+      {
+	__glibcxx_assert(__is_valid_cmpexch_failure_order(__m2));
+
+	return __atomic_compare_exchange_n(&_M_i, &__i1, __i2, 0,
+					   int(__m1), int(__m2));
+      }
+
+      _GLIBCXX_ALWAYS_INLINE bool
+      compare_exchange_strong(__int_type& __i1, __int_type __i2,
+			      memory_order __m1,
+			      memory_order __m2) volatile noexcept
+      {
+	__glibcxx_assert(__is_valid_cmpexch_failure_order(__m2));
+
+	return __atomic_compare_exchange_n(&_M_i, &__i1, __i2, 0,
+					   int(__m1), int(__m2));
+      }
+
+      _GLIBCXX_ALWAYS_INLINE bool
+      compare_exchange_strong(__int_type& __i1, __int_type __i2,
+			      memory_order __m = memory_order_seq_cst) noexcept
+      {
+	return compare_exchange_strong(__i1, __i2, __m,
+				       __cmpexch_failure_order(__m));
+      }
+
+      _GLIBCXX_ALWAYS_INLINE bool
+      compare_exchange_strong(__int_type& __i1, __int_type __i2,
+		 memory_order __m = memory_order_seq_cst) volatile noexcept
+      {
+	return compare_exchange_strong(__i1, __i2, __m,
+				       __cmpexch_failure_order(__m));
+      }
+
+#if __cpp_lib_atomic_wait
+      _GLIBCXX_ALWAYS_INLINE void
+      wait(__int_type __old,
+	  memory_order __m = memory_order_seq_cst) const noexcept
+      {
+	std::__atomic_wait_address_v(&_M_i, __old,
+			   [__m, this] { return this->load(__m); });
+      }
+
+      // TODO add const volatile overload
+
+      _GLIBCXX_ALWAYS_INLINE void
+      notify_one() noexcept
+      { std::__atomic_notify_address(&_M_i, false); }
+
+      // TODO add const volatile overload
+
+      _GLIBCXX_ALWAYS_INLINE void
+      notify_all() noexcept
+      { std::__atomic_notify_address(&_M_i, true); }
+
+      // TODO add const volatile overload
+#endif // __cpp_lib_atomic_wait
+
+      _GLIBCXX_ALWAYS_INLINE __int_type
+      fetch_add(__int_type __i,
+		memory_order __m = memory_order_seq_cst) noexcept
+      { return __atomic_fetch_add(&_M_i, __i, int(__m)); }
+
+      _GLIBCXX_ALWAYS_INLINE __int_type
+      fetch_add(__int_type __i,
+		memory_order __m = memory_order_seq_cst) volatile noexcept
+      { return __atomic_fetch_add(&_M_i, __i, int(__m)); }
+
+      _GLIBCXX_ALWAYS_INLINE __int_type
+      fetch_sub(__int_type __i,
+		memory_order __m = memory_order_seq_cst) noexcept
+      { return __atomic_fetch_sub(&_M_i, __i, int(__m)); }
+
+      _GLIBCXX_ALWAYS_INLINE __int_type
+      fetch_sub(__int_type __i,
+		memory_order __m = memory_order_seq_cst) volatile noexcept
+      { return __atomic_fetch_sub(&_M_i, __i, int(__m)); }
+
+      _GLIBCXX_ALWAYS_INLINE __int_type
+      fetch_and(__int_type __i,
+		memory_order __m = memory_order_seq_cst) noexcept
+      { return __atomic_fetch_and(&_M_i, __i, int(__m)); }
+
+      _GLIBCXX_ALWAYS_INLINE __int_type
+      fetch_and(__int_type __i,
+		memory_order __m = memory_order_seq_cst) volatile noexcept
+      { return __atomic_fetch_and(&_M_i, __i, int(__m)); }
+
+      _GLIBCXX_ALWAYS_INLINE __int_type
+      fetch_or(__int_type __i,
+	       memory_order __m = memory_order_seq_cst) noexcept
+      { return __atomic_fetch_or(&_M_i, __i, int(__m)); }
+
+      _GLIBCXX_ALWAYS_INLINE __int_type
+      fetch_or(__int_type __i,
+	       memory_order __m = memory_order_seq_cst) volatile noexcept
+      { return __atomic_fetch_or(&_M_i, __i, int(__m)); }
+
+      _GLIBCXX_ALWAYS_INLINE __int_type
+      fetch_xor(__int_type __i,
+		memory_order __m = memory_order_seq_cst) noexcept
+      { return __atomic_fetch_xor(&_M_i, __i, int(__m)); }
+
+      _GLIBCXX_ALWAYS_INLINE __int_type
+      fetch_xor(__int_type __i,
+		memory_order __m = memory_order_seq_cst) volatile noexcept
+      { return __atomic_fetch_xor(&_M_i, __i, int(__m)); }
+    };
+
+
+  /// Partial specialization for pointer types.
+  template<typename _PTp>
+    struct __atomic_base<_PTp*>
+    {
+    private:
+      typedef _PTp* 	__pointer_type;
+
+      __pointer_type 	_M_p _GLIBCXX20_INIT(nullptr);
+
+      // Factored out to facilitate explicit specialization.
+      constexpr ptrdiff_t
+      _M_type_size(ptrdiff_t __d) const { return __d * sizeof(_PTp); }
+
+      constexpr ptrdiff_t
+      _M_type_size(ptrdiff_t __d) const volatile { return __d * sizeof(_PTp); }
+
+    public:
+      __atomic_base() noexcept = default;
+      ~__atomic_base() noexcept = default;
+      __atomic_base(const __atomic_base&) = delete;
+      __atomic_base& operator=(const __atomic_base&) = delete;
+      __atomic_base& operator=(const __atomic_base&) volatile = delete;
+
+      // Requires __pointer_type convertible to _M_p.
+      constexpr __atomic_base(__pointer_type __p) noexcept : _M_p (__p) { }
+
+      operator __pointer_type() const noexcept
+      { return load(); }
+
+      operator __pointer_type() const volatile noexcept
+      { return load(); }
+
+      __pointer_type
+      operator=(__pointer_type __p) noexcept
+      {
+	store(__p);
+	return __p;
+      }
+
+      __pointer_type
+      operator=(__pointer_type __p) volatile noexcept
+      {
+	store(__p);
+	return __p;
+      }
+
+      __pointer_type
+      operator++(int) noexcept
+      { return fetch_add(1); }
+
+      __pointer_type
+      operator++(int) volatile noexcept
+      { return fetch_add(1); }
+
+      __pointer_type
+      operator--(int) noexcept
+      { return fetch_sub(1); }
+
+      __pointer_type
+      operator--(int) volatile noexcept
+      { return fetch_sub(1); }
+
+      __pointer_type
+      operator++() noexcept
+      { return __atomic_add_fetch(&_M_p, _M_type_size(1),
+				  int(memory_order_seq_cst)); }
+
+      __pointer_type
+      operator++() volatile noexcept
+      { return __atomic_add_fetch(&_M_p, _M_type_size(1),
+				  int(memory_order_seq_cst)); }
+
+      __pointer_type
+      operator--() noexcept
+      { return __atomic_sub_fetch(&_M_p, _M_type_size(1),
+				  int(memory_order_seq_cst)); }
+
+      __pointer_type
+      operator--() volatile noexcept
+      { return __atomic_sub_fetch(&_M_p, _M_type_size(1),
+				  int(memory_order_seq_cst)); }
+
+      __pointer_type
+      operator+=(ptrdiff_t __d) noexcept
+      { return __atomic_add_fetch(&_M_p, _M_type_size(__d),
+				  int(memory_order_seq_cst)); }
+
+      __pointer_type
+      operator+=(ptrdiff_t __d) volatile noexcept
+      { return __atomic_add_fetch(&_M_p, _M_type_size(__d),
+				  int(memory_order_seq_cst)); }
+
+      __pointer_type
+      operator-=(ptrdiff_t __d) noexcept
+      { return __atomic_sub_fetch(&_M_p, _M_type_size(__d),
+				  int(memory_order_seq_cst)); }
+
+      __pointer_type
+      operator-=(ptrdiff_t __d) volatile noexcept
+      { return __atomic_sub_fetch(&_M_p, _M_type_size(__d),
+				  int(memory_order_seq_cst)); }
+
+      bool
+      is_lock_free() const noexcept
+      {
+	// Produce a fake, minimally aligned pointer.
+	return __atomic_is_lock_free(sizeof(_M_p),
+	    reinterpret_cast<void *>(-__alignof(_M_p)));
+      }
+
+      bool
+      is_lock_free() const volatile noexcept
+      {
+	// Produce a fake, minimally aligned pointer.
+	return __atomic_is_lock_free(sizeof(_M_p),
+	    reinterpret_cast<void *>(-__alignof(_M_p)));
+      }
+
+      _GLIBCXX_ALWAYS_INLINE void
+      store(__pointer_type __p,
+	    memory_order __m = memory_order_seq_cst) noexcept
+      {
+	memory_order __b __attribute__ ((__unused__))
+	  = __m & __memory_order_mask;
+
+	__glibcxx_assert(__b != memory_order_acquire);
+	__glibcxx_assert(__b != memory_order_acq_rel);
+	__glibcxx_assert(__b != memory_order_consume);
+
+	__atomic_store_n(&_M_p, __p, int(__m));
+      }
+
+      _GLIBCXX_ALWAYS_INLINE void
+      store(__pointer_type __p,
+	    memory_order __m = memory_order_seq_cst) volatile noexcept
+      {
+	memory_order __b __attribute__ ((__unused__))
+	  = __m & __memory_order_mask;
+	__glibcxx_assert(__b != memory_order_acquire);
+	__glibcxx_assert(__b != memory_order_acq_rel);
+	__glibcxx_assert(__b != memory_order_consume);
+
+	__atomic_store_n(&_M_p, __p, int(__m));
+      }
+
+      _GLIBCXX_ALWAYS_INLINE __pointer_type
+      load(memory_order __m = memory_order_seq_cst) const noexcept
+      {
+	memory_order __b __attribute__ ((__unused__))
+	  = __m & __memory_order_mask;
+	__glibcxx_assert(__b != memory_order_release);
+	__glibcxx_assert(__b != memory_order_acq_rel);
+
+	return __atomic_load_n(&_M_p, int(__m));
+      }
+
+      _GLIBCXX_ALWAYS_INLINE __pointer_type
+      load(memory_order __m = memory_order_seq_cst) const volatile noexcept
+      {
+	memory_order __b __attribute__ ((__unused__))
+	  = __m & __memory_order_mask;
+	__glibcxx_assert(__b != memory_order_release);
+	__glibcxx_assert(__b != memory_order_acq_rel);
+
+	return __atomic_load_n(&_M_p, int(__m));
+      }
+
+      _GLIBCXX_ALWAYS_INLINE __pointer_type
+      exchange(__pointer_type __p,
+	       memory_order __m = memory_order_seq_cst) noexcept
+      {
+	return __atomic_exchange_n(&_M_p, __p, int(__m));
+      }
+
+
+      _GLIBCXX_ALWAYS_INLINE __pointer_type
+      exchange(__pointer_type __p,
+	       memory_order __m = memory_order_seq_cst) volatile noexcept
+      {
+	return __atomic_exchange_n(&_M_p, __p, int(__m));
+      }
+
+      _GLIBCXX_ALWAYS_INLINE bool
+      compare_exchange_weak(__pointer_type& __p1, __pointer_type __p2,
+			    memory_order __m1,
+			    memory_order __m2) noexcept
+      {
+	__glibcxx_assert(__is_valid_cmpexch_failure_order(__m2));
+
+	return __atomic_compare_exchange_n(&_M_p, &__p1, __p2, 1,
+					   int(__m1), int(__m2));
+      }
+
+      _GLIBCXX_ALWAYS_INLINE bool
+      compare_exchange_weak(__pointer_type& __p1, __pointer_type __p2,
+			    memory_order __m1,
+			    memory_order __m2) volatile noexcept
+      {
+	__glibcxx_assert(__is_valid_cmpexch_failure_order(__m2));
+
+	return __atomic_compare_exchange_n(&_M_p, &__p1, __p2, 1,
+					   int(__m1), int(__m2));
+      }
+
+      _GLIBCXX_ALWAYS_INLINE bool
+      compare_exchange_strong(__pointer_type& __p1, __pointer_type __p2,
+			      memory_order __m1,
+			      memory_order __m2) noexcept
+      {
+	__glibcxx_assert(__is_valid_cmpexch_failure_order(__m2));
+
+	return __atomic_compare_exchange_n(&_M_p, &__p1, __p2, 0,
+					   int(__m1), int(__m2));
+      }
+
+      _GLIBCXX_ALWAYS_INLINE bool
+      compare_exchange_strong(__pointer_type& __p1, __pointer_type __p2,
+			      memory_order __m1,
+			      memory_order __m2) volatile noexcept
+      {
+	__glibcxx_assert(__is_valid_cmpexch_failure_order(__m2));
+
+	return __atomic_compare_exchange_n(&_M_p, &__p1, __p2, 0,
+					   int(__m1), int(__m2));
+      }
+
+#if __cpp_lib_atomic_wait
+      _GLIBCXX_ALWAYS_INLINE void
+      wait(__pointer_type __old,
+	   memory_order __m = memory_order_seq_cst) const noexcept
+      {
+	std::__atomic_wait_address_v(&_M_p, __old,
+				     [__m, this]
+				     { return this->load(__m); });
+      }
+
+      // TODO add const volatile overload
+
+      _GLIBCXX_ALWAYS_INLINE void
+      notify_one() const noexcept
+      { std::__atomic_notify_address(&_M_p, false); }
+
+      // TODO add const volatile overload
+
+      _GLIBCXX_ALWAYS_INLINE void
+      notify_all() const noexcept
+      { std::__atomic_notify_address(&_M_p, true); }
+
+      // TODO add const volatile overload
+#endif // __cpp_lib_atomic_wait
+
+      _GLIBCXX_ALWAYS_INLINE __pointer_type
+      fetch_add(ptrdiff_t __d,
+		memory_order __m = memory_order_seq_cst) noexcept
+      { return __atomic_fetch_add(&_M_p, _M_type_size(__d), int(__m)); }
+
+      _GLIBCXX_ALWAYS_INLINE __pointer_type
+      fetch_add(ptrdiff_t __d,
+		memory_order __m = memory_order_seq_cst) volatile noexcept
+      { return __atomic_fetch_add(&_M_p, _M_type_size(__d), int(__m)); }
+
+      _GLIBCXX_ALWAYS_INLINE __pointer_type
+      fetch_sub(ptrdiff_t __d,
+		memory_order __m = memory_order_seq_cst) noexcept
+      { return __atomic_fetch_sub(&_M_p, _M_type_size(__d), int(__m)); }
+
+      _GLIBCXX_ALWAYS_INLINE __pointer_type
+      fetch_sub(ptrdiff_t __d,
+		memory_order __m = memory_order_seq_cst) volatile noexcept
+      { return __atomic_fetch_sub(&_M_p, _M_type_size(__d), int(__m)); }
+    };
+
+#if __cplusplus > 201703L
+  // Implementation details of atomic_ref and atomic<floating-point>.
+  namespace __atomic_impl
+  {
+    // Remove volatile and create a non-deduced context for value arguments.
+    template<typename _Tp>
+      using _Val = remove_volatile_t<_Tp>;
+
+    // As above, but for difference_type arguments.
+    template<typename _Tp>
+      using _Diff = __conditional_t<is_pointer_v<_Tp>, ptrdiff_t, _Val<_Tp>>;
+
+    template<size_t _Size, size_t _Align>
+      _GLIBCXX_ALWAYS_INLINE bool
+      is_lock_free() noexcept
+      {
+	// Produce a fake, minimally aligned pointer.
+	return __atomic_is_lock_free(_Size, reinterpret_cast<void *>(-_Align));
+      }
+
+    template<typename _Tp>
+      _GLIBCXX_ALWAYS_INLINE void
+      store(_Tp* __ptr, _Val<_Tp> __t, memory_order __m) noexcept
+      { __atomic_store(__ptr, std::__addressof(__t), int(__m)); }
+
+    template<typename _Tp>
+      _GLIBCXX_ALWAYS_INLINE _Val<_Tp>
+      load(const _Tp* __ptr, memory_order __m) noexcept
+      {
+	alignas(_Tp) unsigned char __buf[sizeof(_Tp)];
+	auto* __dest = reinterpret_cast<_Val<_Tp>*>(__buf);
+	__atomic_load(__ptr, __dest, int(__m));
+	return *__dest;
+      }
+
+    template<typename _Tp>
+      _GLIBCXX_ALWAYS_INLINE _Val<_Tp>
+      exchange(_Tp* __ptr, _Val<_Tp> __desired, memory_order __m) noexcept
+      {
+        alignas(_Tp) unsigned char __buf[sizeof(_Tp)];
+	auto* __dest = reinterpret_cast<_Val<_Tp>*>(__buf);
+	__atomic_exchange(__ptr, std::__addressof(__desired), __dest, int(__m));
+	return *__dest;
+      }
+
+    template<typename _Tp>
+      _GLIBCXX_ALWAYS_INLINE bool
+      compare_exchange_weak(_Tp* __ptr, _Val<_Tp>& __expected,
+			    _Val<_Tp> __desired, memory_order __success,
+			    memory_order __failure) noexcept
+      {
+	__glibcxx_assert(__is_valid_cmpexch_failure_order(__failure));
+
+	return __atomic_compare_exchange(__ptr, std::__addressof(__expected),
+					 std::__addressof(__desired), true,
+					 int(__success), int(__failure));
+      }
+
+    template<typename _Tp>
+      _GLIBCXX_ALWAYS_INLINE bool
+      compare_exchange_strong(_Tp* __ptr, _Val<_Tp>& __expected,
+			      _Val<_Tp> __desired, memory_order __success,
+			      memory_order __failure) noexcept
+      {
+	__glibcxx_assert(__is_valid_cmpexch_failure_order(__failure));
+
+	return __atomic_compare_exchange(__ptr, std::__addressof(__expected),
+					 std::__addressof(__desired), false,
+					 int(__success), int(__failure));
+      }
+
+#if __cpp_lib_atomic_wait
+    template<typename _Tp>
+      _GLIBCXX_ALWAYS_INLINE void
+      wait(const _Tp* __ptr, _Val<_Tp> __old,
+	   memory_order __m = memory_order_seq_cst) noexcept
+      {
+	std::__atomic_wait_address_v(__ptr, __old,
+	    [__ptr, __m]() { return __atomic_impl::load(__ptr, __m); });
+      }
+
+      // TODO add const volatile overload
+
+    template<typename _Tp>
+      _GLIBCXX_ALWAYS_INLINE void
+      notify_one(const _Tp* __ptr) noexcept
+      { std::__atomic_notify_address(__ptr, false); }
+
+      // TODO add const volatile overload
+
+    template<typename _Tp>
+      _GLIBCXX_ALWAYS_INLINE void
+      notify_all(const _Tp* __ptr) noexcept
+      { std::__atomic_notify_address(__ptr, true); }
+
+      // TODO add const volatile overload
+#endif // __cpp_lib_atomic_wait
+
+    template<typename _Tp>
+      _GLIBCXX_ALWAYS_INLINE _Tp
+      fetch_add(_Tp* __ptr, _Diff<_Tp> __i, memory_order __m) noexcept
+      { return __atomic_fetch_add(__ptr, __i, int(__m)); }
+
+    template<typename _Tp>
+      _GLIBCXX_ALWAYS_INLINE _Tp
+      fetch_sub(_Tp* __ptr, _Diff<_Tp> __i, memory_order __m) noexcept
+      { return __atomic_fetch_sub(__ptr, __i, int(__m)); }
+
+    template<typename _Tp>
+      _GLIBCXX_ALWAYS_INLINE _Tp
+      fetch_and(_Tp* __ptr, _Val<_Tp> __i, memory_order __m) noexcept
+      { return __atomic_fetch_and(__ptr, __i, int(__m)); }
+
+    template<typename _Tp>
+      _GLIBCXX_ALWAYS_INLINE _Tp
+      fetch_or(_Tp* __ptr, _Val<_Tp> __i, memory_order __m) noexcept
+      { return __atomic_fetch_or(__ptr, __i, int(__m)); }
+
+    template<typename _Tp>
+      _GLIBCXX_ALWAYS_INLINE _Tp
+      fetch_xor(_Tp* __ptr, _Val<_Tp> __i, memory_order __m) noexcept
+      { return __atomic_fetch_xor(__ptr, __i, int(__m)); }
+
+    template<typename _Tp>
+      _GLIBCXX_ALWAYS_INLINE _Tp
+      __add_fetch(_Tp* __ptr, _Diff<_Tp> __i) noexcept
+      { return __atomic_add_fetch(__ptr, __i, __ATOMIC_SEQ_CST); }
+
+    template<typename _Tp>
+      _GLIBCXX_ALWAYS_INLINE _Tp
+      __sub_fetch(_Tp* __ptr, _Diff<_Tp> __i) noexcept
+      { return __atomic_sub_fetch(__ptr, __i, __ATOMIC_SEQ_CST); }
+
+    template<typename _Tp>
+      _GLIBCXX_ALWAYS_INLINE _Tp
+      __and_fetch(_Tp* __ptr, _Val<_Tp> __i) noexcept
+      { return __atomic_and_fetch(__ptr, __i, __ATOMIC_SEQ_CST); }
+
+    template<typename _Tp>
+      _GLIBCXX_ALWAYS_INLINE _Tp
+      __or_fetch(_Tp* __ptr, _Val<_Tp> __i) noexcept
+      { return __atomic_or_fetch(__ptr, __i, __ATOMIC_SEQ_CST); }
+
+    template<typename _Tp>
+      _GLIBCXX_ALWAYS_INLINE _Tp
+      __xor_fetch(_Tp* __ptr, _Val<_Tp> __i) noexcept
+      { return __atomic_xor_fetch(__ptr, __i, __ATOMIC_SEQ_CST); }
+
+    template<typename _Tp>
+      _Tp
+      __fetch_add_flt(_Tp* __ptr, _Val<_Tp> __i, memory_order __m) noexcept
+      {
+	_Val<_Tp> __oldval = load(__ptr, memory_order_relaxed);
+	_Val<_Tp> __newval = __oldval + __i;
+	while (!compare_exchange_weak(__ptr, __oldval, __newval, __m,
+				      memory_order_relaxed))
+	  __newval = __oldval + __i;
+	return __oldval;
+      }
+
+    template<typename _Tp>
+      _Tp
+      __fetch_sub_flt(_Tp* __ptr, _Val<_Tp> __i, memory_order __m) noexcept
+      {
+	_Val<_Tp> __oldval = load(__ptr, memory_order_relaxed);
+	_Val<_Tp> __newval = __oldval - __i;
+	while (!compare_exchange_weak(__ptr, __oldval, __newval, __m,
+				      memory_order_relaxed))
+	  __newval = __oldval - __i;
+	return __oldval;
+      }
+
+    template<typename _Tp>
+      _Tp
+      __add_fetch_flt(_Tp* __ptr, _Val<_Tp> __i) noexcept
+      {
+	_Val<_Tp> __oldval = load(__ptr, memory_order_relaxed);
+	_Val<_Tp> __newval = __oldval + __i;
+	while (!compare_exchange_weak(__ptr, __oldval, __newval,
+				      memory_order_seq_cst,
+				      memory_order_relaxed))
+	  __newval = __oldval + __i;
+	return __newval;
+      }
+
+    template<typename _Tp>
+      _Tp
+      __sub_fetch_flt(_Tp* __ptr, _Val<_Tp> __i) noexcept
+      {
+	_Val<_Tp> __oldval = load(__ptr, memory_order_relaxed);
+	_Val<_Tp> __newval = __oldval - __i;
+	while (!compare_exchange_weak(__ptr, __oldval, __newval,
+				      memory_order_seq_cst,
+				      memory_order_relaxed))
+	  __newval = __oldval - __i;
+	return __newval;
+      }
+  } // namespace __atomic_impl
+
+  // base class for atomic<floating-point-type>
+  template<typename _Fp>
+    struct __atomic_float
+    {
+      static_assert(is_floating_point_v<_Fp>);
+
+      static constexpr size_t _S_alignment = __alignof__(_Fp);
+
+    public:
+      using value_type = _Fp;
+      using difference_type = value_type;
+
+      static constexpr bool is_always_lock_free
+	= __atomic_always_lock_free(sizeof(_Fp), 0);
+
+      __atomic_float() = default;
+
+      constexpr
+      __atomic_float(_Fp __t) : _M_fp(__t)
+      { }
+
+      __atomic_float(const __atomic_float&) = delete;
+      __atomic_float& operator=(const __atomic_float&) = delete;
+      __atomic_float& operator=(const __atomic_float&) volatile = delete;
+
+      _Fp
+      operator=(_Fp __t) volatile noexcept
+      {
+	this->store(__t);
+	return __t;
+      }
+
+      _Fp
+      operator=(_Fp __t) noexcept
+      {
+	this->store(__t);
+	return __t;
+      }
+
+      bool
+      is_lock_free() const volatile noexcept
+      { return __atomic_impl::is_lock_free<sizeof(_Fp), _S_alignment>(); }
+
+      bool
+      is_lock_free() const noexcept
+      { return __atomic_impl::is_lock_free<sizeof(_Fp), _S_alignment>(); }
+
+      void
+      store(_Fp __t, memory_order __m = memory_order_seq_cst) volatile noexcept
+      { __atomic_impl::store(&_M_fp, __t, __m); }
+
+      void
+      store(_Fp __t, memory_order __m = memory_order_seq_cst) noexcept
+      { __atomic_impl::store(&_M_fp, __t, __m); }
+
+      _Fp
+      load(memory_order __m = memory_order_seq_cst) const volatile noexcept
+      { return __atomic_impl::load(&_M_fp, __m); }
+
+      _Fp
+      load(memory_order __m = memory_order_seq_cst) const noexcept
+      { return __atomic_impl::load(&_M_fp, __m); }
+
+      operator _Fp() const volatile noexcept { return this->load(); }
+      operator _Fp() const noexcept { return this->load(); }
+
+      _Fp
+      exchange(_Fp __desired,
+	       memory_order __m = memory_order_seq_cst) volatile noexcept
+      { return __atomic_impl::exchange(&_M_fp, __desired, __m); }
+
+      _Fp
+      exchange(_Fp __desired,
+	       memory_order __m = memory_order_seq_cst) noexcept
+      { return __atomic_impl::exchange(&_M_fp, __desired, __m); }
+
+      bool
+      compare_exchange_weak(_Fp& __expected, _Fp __desired,
+			    memory_order __success,
+			    memory_order __failure) noexcept
+      {
+	return __atomic_impl::compare_exchange_weak(&_M_fp,
+						    __expected, __desired,
+						    __success, __failure);
+      }
+
+      bool
+      compare_exchange_weak(_Fp& __expected, _Fp __desired,
+			    memory_order __success,
+			    memory_order __failure) volatile noexcept
+      {
+	return __atomic_impl::compare_exchange_weak(&_M_fp,
+						    __expected, __desired,
+						    __success, __failure);
+      }
+
+      bool
+      compare_exchange_strong(_Fp& __expected, _Fp __desired,
+			      memory_order __success,
+			      memory_order __failure) noexcept
+      {
+	return __atomic_impl::compare_exchange_strong(&_M_fp,
+						      __expected, __desired,
+						      __success, __failure);
+      }
+
+      bool
+      compare_exchange_strong(_Fp& __expected, _Fp __desired,
+			      memory_order __success,
+			      memory_order __failure) volatile noexcept
+      {
+	return __atomic_impl::compare_exchange_strong(&_M_fp,
+						      __expected, __desired,
+						      __success, __failure);
+      }
+
+      bool
+      compare_exchange_weak(_Fp& __expected, _Fp __desired,
+			    memory_order __order = memory_order_seq_cst)
+      noexcept
+      {
+	return compare_exchange_weak(__expected, __desired, __order,
+                                     __cmpexch_failure_order(__order));
+      }
+
+      bool
+      compare_exchange_weak(_Fp& __expected, _Fp __desired,
+			    memory_order __order = memory_order_seq_cst)
+      volatile noexcept
+      {
+	return compare_exchange_weak(__expected, __desired, __order,
+                                     __cmpexch_failure_order(__order));
+      }
+
+      bool
+      compare_exchange_strong(_Fp& __expected, _Fp __desired,
+			      memory_order __order = memory_order_seq_cst)
+      noexcept
+      {
+	return compare_exchange_strong(__expected, __desired, __order,
+				       __cmpexch_failure_order(__order));
+      }
+
+      bool
+      compare_exchange_strong(_Fp& __expected, _Fp __desired,
+			      memory_order __order = memory_order_seq_cst)
+      volatile noexcept
+      {
+	return compare_exchange_strong(__expected, __desired, __order,
+				       __cmpexch_failure_order(__order));
+      }
+
+#if __cpp_lib_atomic_wait
+      _GLIBCXX_ALWAYS_INLINE void
+      wait(_Fp __old, memory_order __m = memory_order_seq_cst) const noexcept
+      { __atomic_impl::wait(&_M_fp, __old, __m); }
+
+      // TODO add const volatile overload
+
+      _GLIBCXX_ALWAYS_INLINE void
+      notify_one() const noexcept
+      { __atomic_impl::notify_one(&_M_fp); }
+
+      // TODO add const volatile overload
+
+      _GLIBCXX_ALWAYS_INLINE void
+      notify_all() const noexcept
+      { __atomic_impl::notify_all(&_M_fp); }
+
+      // TODO add const volatile overload
+#endif // __cpp_lib_atomic_wait
+
+      value_type
+      fetch_add(value_type __i,
+		memory_order __m = memory_order_seq_cst) noexcept
+      { return __atomic_impl::__fetch_add_flt(&_M_fp, __i, __m); }
+
+      value_type
+      fetch_add(value_type __i,
+		memory_order __m = memory_order_seq_cst) volatile noexcept
+      { return __atomic_impl::__fetch_add_flt(&_M_fp, __i, __m); }
+
+      value_type
+      fetch_sub(value_type __i,
+		memory_order __m = memory_order_seq_cst) noexcept
+      { return __atomic_impl::__fetch_sub_flt(&_M_fp, __i, __m); }
+
+      value_type
+      fetch_sub(value_type __i,
+		memory_order __m = memory_order_seq_cst) volatile noexcept
+      { return __atomic_impl::__fetch_sub_flt(&_M_fp, __i, __m); }
+
+      value_type
+      operator+=(value_type __i) noexcept
+      { return __atomic_impl::__add_fetch_flt(&_M_fp, __i); }
+
+      value_type
+      operator+=(value_type __i) volatile noexcept
+      { return __atomic_impl::__add_fetch_flt(&_M_fp, __i); }
+
+      value_type
+      operator-=(value_type __i) noexcept
+      { return __atomic_impl::__sub_fetch_flt(&_M_fp, __i); }
+
+      value_type
+      operator-=(value_type __i) volatile noexcept
+      { return __atomic_impl::__sub_fetch_flt(&_M_fp, __i); }
+
+    private:
+      alignas(_S_alignment) _Fp _M_fp _GLIBCXX20_INIT(0);
+    };
+#undef _GLIBCXX20_INIT
+
+  template<typename _Tp,
+	   bool = is_integral_v<_Tp>, bool = is_floating_point_v<_Tp>>
+    struct __atomic_ref;
+
+  // base class for non-integral, non-floating-point, non-pointer types
+  template<typename _Tp>
+    struct __atomic_ref<_Tp, false, false>
+    {
+      static_assert(is_trivially_copyable_v<_Tp>);
+
+      // 1/2/4/8/16-byte types must be aligned to at least their size.
+      static constexpr int _S_min_alignment
+	= (sizeof(_Tp) & (sizeof(_Tp) - 1)) || sizeof(_Tp) > 16
+	? 0 : sizeof(_Tp);
+
+    public:
+      using value_type = _Tp;
+
+      static constexpr bool is_always_lock_free
+	= __atomic_always_lock_free(sizeof(_Tp), 0);
+
+      static constexpr size_t required_alignment
+	= _S_min_alignment > alignof(_Tp) ? _S_min_alignment : alignof(_Tp);
+
+      __atomic_ref& operator=(const __atomic_ref&) = delete;
+
+      explicit
+      __atomic_ref(_Tp& __t) : _M_ptr(std::__addressof(__t))
+      { __glibcxx_assert(((uintptr_t)_M_ptr % required_alignment) == 0); }
+
+      __atomic_ref(const __atomic_ref&) noexcept = default;
+
+      _Tp
+      operator=(_Tp __t) const noexcept
+      {
+	this->store(__t);
+	return __t;
+      }
+
+      operator _Tp() const noexcept { return this->load(); }
+
+      bool
+      is_lock_free() const noexcept
+      { return __atomic_impl::is_lock_free<sizeof(_Tp), required_alignment>(); }
+
+      void
+      store(_Tp __t, memory_order __m = memory_order_seq_cst) const noexcept
+      { __atomic_impl::store(_M_ptr, __t, __m); }
+
+      _Tp
+      load(memory_order __m = memory_order_seq_cst) const noexcept
+      { return __atomic_impl::load(_M_ptr, __m); }
+
+      _Tp
+      exchange(_Tp __desired, memory_order __m = memory_order_seq_cst)
+      const noexcept
+      { return __atomic_impl::exchange(_M_ptr, __desired, __m); }
+
+      bool
+      compare_exchange_weak(_Tp& __expected, _Tp __desired,
+			    memory_order __success,
+			    memory_order __failure) const noexcept
+      {
+	return __atomic_impl::compare_exchange_weak(_M_ptr,
+						    __expected, __desired,
+						    __success, __failure);
+      }
+
+      bool
+      compare_exchange_strong(_Tp& __expected, _Tp __desired,
+			    memory_order __success,
+			    memory_order __failure) const noexcept
+      {
+	return __atomic_impl::compare_exchange_strong(_M_ptr,
+						      __expected, __desired,
+						      __success, __failure);
+      }
+
+      bool
+      compare_exchange_weak(_Tp& __expected, _Tp __desired,
+			    memory_order __order = memory_order_seq_cst)
+      const noexcept
+      {
+	return compare_exchange_weak(__expected, __desired, __order,
+                                     __cmpexch_failure_order(__order));
+      }
+
+      bool
+      compare_exchange_strong(_Tp& __expected, _Tp __desired,
+			      memory_order __order = memory_order_seq_cst)
+      const noexcept
+      {
+	return compare_exchange_strong(__expected, __desired, __order,
+				       __cmpexch_failure_order(__order));
+      }
+
+#if __cpp_lib_atomic_wait
+      _GLIBCXX_ALWAYS_INLINE void
+      wait(_Tp __old, memory_order __m = memory_order_seq_cst) const noexcept
+      { __atomic_impl::wait(_M_ptr, __old, __m); }
+
+      // TODO add const volatile overload
+
+      _GLIBCXX_ALWAYS_INLINE void
+      notify_one() const noexcept
+      { __atomic_impl::notify_one(_M_ptr); }
+
+      // TODO add const volatile overload
+
+      _GLIBCXX_ALWAYS_INLINE void
+      notify_all() const noexcept
+      { __atomic_impl::notify_all(_M_ptr); }
+
+      // TODO add const volatile overload
+#endif // __cpp_lib_atomic_wait
+
+    private:
+      _Tp* _M_ptr;
+    };
+
+  // base class for atomic_ref<integral-type>
+  template<typename _Tp>
+    struct __atomic_ref<_Tp, true, false>
+    {
+      static_assert(is_integral_v<_Tp>);
+
+    public:
+      using value_type = _Tp;
+      using difference_type = value_type;
+
+      static constexpr bool is_always_lock_free
+	= __atomic_always_lock_free(sizeof(_Tp), 0);
+
+      static constexpr size_t required_alignment
+	= sizeof(_Tp) > alignof(_Tp) ? sizeof(_Tp) : alignof(_Tp);
+
+      __atomic_ref() = delete;
+      __atomic_ref& operator=(const __atomic_ref&) = delete;
+
+      explicit
+      __atomic_ref(_Tp& __t) : _M_ptr(&__t)
+      { __glibcxx_assert(((uintptr_t)_M_ptr % required_alignment) == 0); }
+
+      __atomic_ref(const __atomic_ref&) noexcept = default;
+
+      _Tp
+      operator=(_Tp __t) const noexcept
+      {
+	this->store(__t);
+	return __t;
+      }
+
+      operator _Tp() const noexcept { return this->load(); }
+
+      bool
+      is_lock_free() const noexcept
+      {
+	return __atomic_impl::is_lock_free<sizeof(_Tp), required_alignment>();
+      }
+
+      void
+      store(_Tp __t, memory_order __m = memory_order_seq_cst) const noexcept
+      { __atomic_impl::store(_M_ptr, __t, __m); }
+
+      _Tp
+      load(memory_order __m = memory_order_seq_cst) const noexcept
+      { return __atomic_impl::load(_M_ptr, __m); }
+
+      _Tp
+      exchange(_Tp __desired,
+	       memory_order __m = memory_order_seq_cst) const noexcept
+      { return __atomic_impl::exchange(_M_ptr, __desired, __m); }
+
+      bool
+      compare_exchange_weak(_Tp& __expected, _Tp __desired,
+			    memory_order __success,
+			    memory_order __failure) const noexcept
+      {
+	return __atomic_impl::compare_exchange_weak(_M_ptr,
+						    __expected, __desired,
+						    __success, __failure);
+      }
+
+      bool
+      compare_exchange_strong(_Tp& __expected, _Tp __desired,
+			      memory_order __success,
+			      memory_order __failure) const noexcept
+      {
+	return __atomic_impl::compare_exchange_strong(_M_ptr,
+						      __expected, __desired,
+						      __success, __failure);
+      }
+
+      bool
+      compare_exchange_weak(_Tp& __expected, _Tp __desired,
+			    memory_order __order = memory_order_seq_cst)
+      const noexcept
+      {
+	return compare_exchange_weak(__expected, __desired, __order,
+                                     __cmpexch_failure_order(__order));
+      }
+
+      bool
+      compare_exchange_strong(_Tp& __expected, _Tp __desired,
+			      memory_order __order = memory_order_seq_cst)
+      const noexcept
+      {
+	return compare_exchange_strong(__expected, __desired, __order,
+				       __cmpexch_failure_order(__order));
+      }
+
+#if __cpp_lib_atomic_wait
+      _GLIBCXX_ALWAYS_INLINE void
+      wait(_Tp __old, memory_order __m = memory_order_seq_cst) const noexcept
+      { __atomic_impl::wait(_M_ptr, __old, __m); }
+
+      // TODO add const volatile overload
+
+      _GLIBCXX_ALWAYS_INLINE void
+      notify_one() const noexcept
+      { __atomic_impl::notify_one(_M_ptr); }
+
+      // TODO add const volatile overload
+
+      _GLIBCXX_ALWAYS_INLINE void
+      notify_all() const noexcept
+      { __atomic_impl::notify_all(_M_ptr); }
+
+      // TODO add const volatile overload
+#endif // __cpp_lib_atomic_wait 
+
+      value_type
+      fetch_add(value_type __i,
+		memory_order __m = memory_order_seq_cst) const noexcept
+      { return __atomic_impl::fetch_add(_M_ptr, __i, __m); }
+
+      value_type
+      fetch_sub(value_type __i,
+		memory_order __m = memory_order_seq_cst) const noexcept
+      { return __atomic_impl::fetch_sub(_M_ptr, __i, __m); }
+
+      value_type
+      fetch_and(value_type __i,
+		memory_order __m = memory_order_seq_cst) const noexcept
+      { return __atomic_impl::fetch_and(_M_ptr, __i, __m); }
+
+      value_type
+      fetch_or(value_type __i,
+	       memory_order __m = memory_order_seq_cst) const noexcept
+      { return __atomic_impl::fetch_or(_M_ptr, __i, __m); }
+
+      value_type
+      fetch_xor(value_type __i,
+		memory_order __m = memory_order_seq_cst) const noexcept
+      { return __atomic_impl::fetch_xor(_M_ptr, __i, __m); }
+
+      _GLIBCXX_ALWAYS_INLINE value_type
+      operator++(int) const noexcept
+      { return fetch_add(1); }
+
+      _GLIBCXX_ALWAYS_INLINE value_type
+      operator--(int) const noexcept
+      { return fetch_sub(1); }
+
+      value_type
+      operator++() const noexcept
+      { return __atomic_impl::__add_fetch(_M_ptr, value_type(1)); }
+
+      value_type
+      operator--() const noexcept
+      { return __atomic_impl::__sub_fetch(_M_ptr, value_type(1)); }
+
+      value_type
+      operator+=(value_type __i) const noexcept
+      { return __atomic_impl::__add_fetch(_M_ptr, __i); }
+
+      value_type
+      operator-=(value_type __i) const noexcept
+      { return __atomic_impl::__sub_fetch(_M_ptr, __i); }
+
+      value_type
+      operator&=(value_type __i) const noexcept
+      { return __atomic_impl::__and_fetch(_M_ptr, __i); }
+
+      value_type
+      operator|=(value_type __i) const noexcept
+      { return __atomic_impl::__or_fetch(_M_ptr, __i); }
+
+      value_type
+      operator^=(value_type __i) const noexcept
+      { return __atomic_impl::__xor_fetch(_M_ptr, __i); }
+
+    private:
+      _Tp* _M_ptr;
+    };
+
+  // base class for atomic_ref<floating-point-type>
+  template<typename _Fp>
+    struct __atomic_ref<_Fp, false, true>
+    {
+      static_assert(is_floating_point_v<_Fp>);
+
+    public:
+      using value_type = _Fp;
+      using difference_type = value_type;
+
+      static constexpr bool is_always_lock_free
+	= __atomic_always_lock_free(sizeof(_Fp), 0);
+
+      static constexpr size_t required_alignment = __alignof__(_Fp);
+
+      __atomic_ref() = delete;
+      __atomic_ref& operator=(const __atomic_ref&) = delete;
+
+      explicit
+      __atomic_ref(_Fp& __t) : _M_ptr(&__t)
+      { __glibcxx_assert(((uintptr_t)_M_ptr % required_alignment) == 0); }
+
+      __atomic_ref(const __atomic_ref&) noexcept = default;
+
+      _Fp
+      operator=(_Fp __t) const noexcept
+      {
+	this->store(__t);
+	return __t;
+      }
+
+      operator _Fp() const noexcept { return this->load(); }
+
+      bool
+      is_lock_free() const noexcept
+      {
+	return __atomic_impl::is_lock_free<sizeof(_Fp), required_alignment>();
+      }
+
+      void
+      store(_Fp __t, memory_order __m = memory_order_seq_cst) const noexcept
+      { __atomic_impl::store(_M_ptr, __t, __m); }
+
+      _Fp
+      load(memory_order __m = memory_order_seq_cst) const noexcept
+      { return __atomic_impl::load(_M_ptr, __m); }
+
+      _Fp
+      exchange(_Fp __desired,
+	       memory_order __m = memory_order_seq_cst) const noexcept
+      { return __atomic_impl::exchange(_M_ptr, __desired, __m); }
+
+      bool
+      compare_exchange_weak(_Fp& __expected, _Fp __desired,
+			    memory_order __success,
+			    memory_order __failure) const noexcept
+      {
+	return __atomic_impl::compare_exchange_weak(_M_ptr,
+						    __expected, __desired,
+						    __success, __failure);
+      }
+
+      bool
+      compare_exchange_strong(_Fp& __expected, _Fp __desired,
+			    memory_order __success,
+			    memory_order __failure) const noexcept
+      {
+	return __atomic_impl::compare_exchange_strong(_M_ptr,
+						      __expected, __desired,
+						      __success, __failure);
+      }
+
+      bool
+      compare_exchange_weak(_Fp& __expected, _Fp __desired,
+			    memory_order __order = memory_order_seq_cst)
+      const noexcept
+      {
+	return compare_exchange_weak(__expected, __desired, __order,
+                                     __cmpexch_failure_order(__order));
+      }
+
+      bool
+      compare_exchange_strong(_Fp& __expected, _Fp __desired,
+			      memory_order __order = memory_order_seq_cst)
+      const noexcept
+      {
+	return compare_exchange_strong(__expected, __desired, __order,
+				       __cmpexch_failure_order(__order));
+      }
+
+#if __cpp_lib_atomic_wait
+      _GLIBCXX_ALWAYS_INLINE void
+      wait(_Fp __old, memory_order __m = memory_order_seq_cst) const noexcept
+      { __atomic_impl::wait(_M_ptr, __old, __m); }
+
+      // TODO add const volatile overload
+
+      _GLIBCXX_ALWAYS_INLINE void
+      notify_one() const noexcept
+      { __atomic_impl::notify_one(_M_ptr); }
+
+      // TODO add const volatile overload
+
+      _GLIBCXX_ALWAYS_INLINE void
+      notify_all() const noexcept
+      { __atomic_impl::notify_all(_M_ptr); }
+
+      // TODO add const volatile overload
+#endif // __cpp_lib_atomic_wait
+
+      value_type
+      fetch_add(value_type __i,
+		memory_order __m = memory_order_seq_cst) const noexcept
+      { return __atomic_impl::__fetch_add_flt(_M_ptr, __i, __m); }
+
+      value_type
+      fetch_sub(value_type __i,
+		memory_order __m = memory_order_seq_cst) const noexcept
+      { return __atomic_impl::__fetch_sub_flt(_M_ptr, __i, __m); }
+
+      value_type
+      operator+=(value_type __i) const noexcept
+      { return __atomic_impl::__add_fetch_flt(_M_ptr, __i); }
+
+      value_type
+      operator-=(value_type __i) const noexcept
+      { return __atomic_impl::__sub_fetch_flt(_M_ptr, __i); }
+
+    private:
+      _Fp* _M_ptr;
+    };
+
+  // base class for atomic_ref<pointer-type>
+  template<typename _Tp>
+    struct __atomic_ref<_Tp*, false, false>
+    {
+    public:
+      using value_type = _Tp*;
+      using difference_type = ptrdiff_t;
+
+      static constexpr bool is_always_lock_free = ATOMIC_POINTER_LOCK_FREE == 2;
+
+      static constexpr size_t required_alignment = __alignof__(_Tp*);
+
+      __atomic_ref() = delete;
+      __atomic_ref& operator=(const __atomic_ref&) = delete;
+
+      explicit
+      __atomic_ref(_Tp*& __t) : _M_ptr(std::__addressof(__t))
+      { __glibcxx_assert(((uintptr_t)_M_ptr % required_alignment) == 0); }
+
+      __atomic_ref(const __atomic_ref&) noexcept = default;
+
+      _Tp*
+      operator=(_Tp* __t) const noexcept
+      {
+	this->store(__t);
+	return __t;
+      }
+
+      operator _Tp*() const noexcept { return this->load(); }
+
+      bool
+      is_lock_free() const noexcept
+      {
+	return __atomic_impl::is_lock_free<sizeof(_Tp*), required_alignment>();
+      }
+
+      void
+      store(_Tp* __t, memory_order __m = memory_order_seq_cst) const noexcept
+      { __atomic_impl::store(_M_ptr, __t, __m); }
+
+      _Tp*
+      load(memory_order __m = memory_order_seq_cst) const noexcept
+      { return __atomic_impl::load(_M_ptr, __m); }
+
+      _Tp*
+      exchange(_Tp* __desired,
+	       memory_order __m = memory_order_seq_cst) const noexcept
+      { return __atomic_impl::exchange(_M_ptr, __desired, __m); }
+
+      bool
+      compare_exchange_weak(_Tp*& __expected, _Tp* __desired,
+			    memory_order __success,
+			    memory_order __failure) const noexcept
+      {
+	return __atomic_impl::compare_exchange_weak(_M_ptr,
+						    __expected, __desired,
+						    __success, __failure);
+      }
+
+      bool
+      compare_exchange_strong(_Tp*& __expected, _Tp* __desired,
+			    memory_order __success,
+			    memory_order __failure) const noexcept
+      {
+	return __atomic_impl::compare_exchange_strong(_M_ptr,
+						      __expected, __desired,
+						      __success, __failure);
+      }
+
+      bool
+      compare_exchange_weak(_Tp*& __expected, _Tp* __desired,
+			    memory_order __order = memory_order_seq_cst)
+      const noexcept
+      {
+	return compare_exchange_weak(__expected, __desired, __order,
+                                     __cmpexch_failure_order(__order));
+      }
+
+      bool
+      compare_exchange_strong(_Tp*& __expected, _Tp* __desired,
+			      memory_order __order = memory_order_seq_cst)
+      const noexcept
+      {
+	return compare_exchange_strong(__expected, __desired, __order,
+				       __cmpexch_failure_order(__order));
+      }
+
+#if __cpp_lib_atomic_wait
+      _GLIBCXX_ALWAYS_INLINE void
+      wait(_Tp* __old, memory_order __m = memory_order_seq_cst) const noexcept
+      { __atomic_impl::wait(_M_ptr, __old, __m); }
+
+      // TODO add const volatile overload
+
+      _GLIBCXX_ALWAYS_INLINE void
+      notify_one() const noexcept
+      { __atomic_impl::notify_one(_M_ptr); }
+
+      // TODO add const volatile overload
+
+      _GLIBCXX_ALWAYS_INLINE void
+      notify_all() const noexcept
+      { __atomic_impl::notify_all(_M_ptr); }
+
+      // TODO add const volatile overload
+#endif // __cpp_lib_atomic_wait
+
+      _GLIBCXX_ALWAYS_INLINE value_type
+      fetch_add(difference_type __d,
+		memory_order __m = memory_order_seq_cst) const noexcept
+      { return __atomic_impl::fetch_add(_M_ptr, _S_type_size(__d), __m); }
+
+      _GLIBCXX_ALWAYS_INLINE value_type
+      fetch_sub(difference_type __d,
+		memory_order __m = memory_order_seq_cst) const noexcept
+      { return __atomic_impl::fetch_sub(_M_ptr, _S_type_size(__d), __m); }
+
+      value_type
+      operator++(int) const noexcept
+      { return fetch_add(1); }
+
+      value_type
+      operator--(int) const noexcept
+      { return fetch_sub(1); }
+
+      value_type
+      operator++() const noexcept
+      {
+	return __atomic_impl::__add_fetch(_M_ptr, _S_type_size(1));
+      }
+
+      value_type
+      operator--() const noexcept
+      {
+	return __atomic_impl::__sub_fetch(_M_ptr, _S_type_size(1));
+      }
+
+      value_type
+      operator+=(difference_type __d) const noexcept
+      {
+	return __atomic_impl::__add_fetch(_M_ptr, _S_type_size(__d));
+      }
+
+      value_type
+      operator-=(difference_type __d) const noexcept
+      {
+	return __atomic_impl::__sub_fetch(_M_ptr, _S_type_size(__d));
+      }
+
+    private:
+      static constexpr ptrdiff_t
+      _S_type_size(ptrdiff_t __d) noexcept
+      {
+	static_assert(is_object_v<_Tp>);
+	return __d * sizeof(_Tp);
+      }
+
+      _Tp** _M_ptr;
+    };
+
+#endif // C++2a
+
+  /// @} group atomics
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif
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@@ -0,0 +1,360 @@
+// -*- C++ -*- header.
+
+// Copyright (C) 2015-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/atomic_futex.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly.
+ */
+
+#ifndef _GLIBCXX_ATOMIC_FUTEX_H
+#define _GLIBCXX_ATOMIC_FUTEX_H 1
+
+#pragma GCC system_header
+
+#include <atomic>
+#if ! (defined(_GLIBCXX_HAVE_LINUX_FUTEX) && ATOMIC_INT_LOCK_FREE > 1)
+#include <mutex>
+#include <condition_variable>
+#endif
+#include <bits/chrono.h>
+
+#ifndef _GLIBCXX_ALWAYS_INLINE
+#define _GLIBCXX_ALWAYS_INLINE inline __attribute__((__always_inline__))
+#endif
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+#ifdef _GLIBCXX_HAS_GTHREADS
+#if defined(_GLIBCXX_HAVE_LINUX_FUTEX) && ATOMIC_INT_LOCK_FREE > 1
+  struct __atomic_futex_unsigned_base
+  {
+    // __s and __ns are measured against CLOCK_REALTIME. Returns false
+    // iff a timeout occurred.
+    bool
+    _M_futex_wait_until(unsigned *__addr, unsigned __val, bool __has_timeout,
+	chrono::seconds __s, chrono::nanoseconds __ns);
+
+    // __s and __ns are measured against CLOCK_MONOTONIC. Returns
+    // false iff a timeout occurred.
+    bool
+    _M_futex_wait_until_steady(unsigned *__addr, unsigned __val,
+	bool __has_timeout, chrono::seconds __s, chrono::nanoseconds __ns);
+
+    // This can be executed after the object has been destroyed.
+    static void _M_futex_notify_all(unsigned* __addr);
+  };
+
+  template <unsigned _Waiter_bit = 0x80000000>
+  class __atomic_futex_unsigned : __atomic_futex_unsigned_base
+  {
+    typedef chrono::steady_clock __clock_t;
+
+    // This must be lock-free and at offset 0.
+    atomic<unsigned> _M_data;
+
+  public:
+    explicit
+    __atomic_futex_unsigned(unsigned __data) : _M_data(__data)
+    { }
+
+    _GLIBCXX_ALWAYS_INLINE unsigned
+    _M_load(memory_order __mo)
+    {
+      return _M_data.load(__mo) & ~_Waiter_bit;
+    }
+
+  private:
+    // If a timeout occurs, returns a current value after the timeout;
+    // otherwise, returns the operand's value if equal is true or a different
+    // value if equal is false.
+    // The assumed value is the caller's assumption about the current value
+    // when making the call.
+    // __s and __ns are measured against CLOCK_REALTIME.
+    unsigned
+    _M_load_and_test_until(unsigned __assumed, unsigned __operand,
+	bool __equal, memory_order __mo, bool __has_timeout,
+	chrono::seconds __s, chrono::nanoseconds __ns)
+    {
+      for (;;)
+	{
+	  // Don't bother checking the value again because we expect the caller
+	  // to have done it recently.
+	  // memory_order_relaxed is sufficient because we can rely on just the
+	  // modification order (store_notify uses an atomic RMW operation too),
+	  // and the futex syscalls synchronize between themselves.
+	  _M_data.fetch_or(_Waiter_bit, memory_order_relaxed);
+	  bool __ret = _M_futex_wait_until((unsigned*)(void*)&_M_data,
+					   __assumed | _Waiter_bit,
+					   __has_timeout, __s, __ns);
+	  // Fetch the current value after waiting (clears _Waiter_bit).
+	  __assumed = _M_load(__mo);
+	  if (!__ret || ((__operand == __assumed) == __equal))
+	    return __assumed;
+	  // TODO adapt wait time
+	}
+    }
+
+    // If a timeout occurs, returns a current value after the timeout;
+    // otherwise, returns the operand's value if equal is true or a different
+    // value if equal is false.
+    // The assumed value is the caller's assumption about the current value
+    // when making the call.
+    // __s and __ns are measured against CLOCK_MONOTONIC.
+    unsigned
+    _M_load_and_test_until_steady(unsigned __assumed, unsigned __operand,
+	bool __equal, memory_order __mo, bool __has_timeout,
+	chrono::seconds __s, chrono::nanoseconds __ns)
+    {
+      for (;;)
+	{
+	  // Don't bother checking the value again because we expect the caller
+	  // to have done it recently.
+	  // memory_order_relaxed is sufficient because we can rely on just the
+	  // modification order (store_notify uses an atomic RMW operation too),
+	  // and the futex syscalls synchronize between themselves.
+	  _M_data.fetch_or(_Waiter_bit, memory_order_relaxed);
+	  bool __ret = _M_futex_wait_until_steady((unsigned*)(void*)&_M_data,
+					   __assumed | _Waiter_bit,
+					   __has_timeout, __s, __ns);
+	  // Fetch the current value after waiting (clears _Waiter_bit).
+	  __assumed = _M_load(__mo);
+	  if (!__ret || ((__operand == __assumed) == __equal))
+	    return __assumed;
+	  // TODO adapt wait time
+	}
+    }
+
+    // Returns the operand's value if equal is true or a different value if
+    // equal is false.
+    // The assumed value is the caller's assumption about the current value
+    // when making the call.
+    unsigned
+    _M_load_and_test(unsigned __assumed, unsigned __operand,
+	bool __equal, memory_order __mo)
+    {
+      return _M_load_and_test_until(__assumed, __operand, __equal, __mo,
+				    false, {}, {});
+    }
+
+    // If a timeout occurs, returns a current value after the timeout;
+    // otherwise, returns the operand's value if equal is true or a different
+    // value if equal is false.
+    // The assumed value is the caller's assumption about the current value
+    // when making the call.
+    template<typename _Dur>
+    unsigned
+    _M_load_and_test_until_impl(unsigned __assumed, unsigned __operand,
+	bool __equal, memory_order __mo,
+	const chrono::time_point<std::chrono::system_clock, _Dur>& __atime)
+    {
+      auto __s = chrono::time_point_cast<chrono::seconds>(__atime);
+      auto __ns = chrono::duration_cast<chrono::nanoseconds>(__atime - __s);
+      // XXX correct?
+      return _M_load_and_test_until(__assumed, __operand, __equal, __mo,
+	  true, __s.time_since_epoch(), __ns);
+    }
+
+    template<typename _Dur>
+    unsigned
+    _M_load_and_test_until_impl(unsigned __assumed, unsigned __operand,
+	bool __equal, memory_order __mo,
+	const chrono::time_point<std::chrono::steady_clock, _Dur>& __atime)
+    {
+      auto __s = chrono::time_point_cast<chrono::seconds>(__atime);
+      auto __ns = chrono::duration_cast<chrono::nanoseconds>(__atime - __s);
+      // XXX correct?
+      return _M_load_and_test_until_steady(__assumed, __operand, __equal, __mo,
+	  true, __s.time_since_epoch(), __ns);
+    }
+
+  public:
+
+    _GLIBCXX_ALWAYS_INLINE unsigned
+    _M_load_when_not_equal(unsigned __val, memory_order __mo)
+    {
+      unsigned __i = _M_load(__mo);
+      if ((__i & ~_Waiter_bit) != __val)
+	return (__i & ~_Waiter_bit);
+      // TODO Spin-wait first.
+      return _M_load_and_test(__i, __val, false, __mo);
+    }
+
+    _GLIBCXX_ALWAYS_INLINE void
+    _M_load_when_equal(unsigned __val, memory_order __mo)
+    {
+      unsigned __i = _M_load(__mo);
+      if ((__i & ~_Waiter_bit) == __val)
+	return;
+      // TODO Spin-wait first.
+      _M_load_and_test(__i, __val, true, __mo);
+    }
+
+    // Returns false iff a timeout occurred.
+    template<typename _Rep, typename _Period>
+      _GLIBCXX_ALWAYS_INLINE bool
+      _M_load_when_equal_for(unsigned __val, memory_order __mo,
+	  const chrono::duration<_Rep, _Period>& __rtime)
+      {
+	using __dur = typename __clock_t::duration;
+	return _M_load_when_equal_until(__val, __mo,
+		    __clock_t::now() + chrono::__detail::ceil<__dur>(__rtime));
+      }
+
+    // Returns false iff a timeout occurred.
+    template<typename _Clock, typename _Duration>
+      _GLIBCXX_ALWAYS_INLINE bool
+      _M_load_when_equal_until(unsigned __val, memory_order __mo,
+	  const chrono::time_point<_Clock, _Duration>& __atime)
+      {
+	typename _Clock::time_point __c_entry = _Clock::now();
+	do {
+	  const __clock_t::time_point __s_entry = __clock_t::now();
+	  const auto __delta = __atime - __c_entry;
+	  const auto __s_atime = __s_entry +
+	      chrono::__detail::ceil<__clock_t::duration>(__delta);
+	  if (_M_load_when_equal_until(__val, __mo, __s_atime))
+	    return true;
+	  __c_entry = _Clock::now();
+	} while (__c_entry < __atime);
+	return false;
+      }
+
+    // Returns false iff a timeout occurred.
+    template<typename _Duration>
+    _GLIBCXX_ALWAYS_INLINE bool
+    _M_load_when_equal_until(unsigned __val, memory_order __mo,
+	const chrono::time_point<std::chrono::system_clock, _Duration>& __atime)
+    {
+      unsigned __i = _M_load(__mo);
+      if ((__i & ~_Waiter_bit) == __val)
+	return true;
+      // TODO Spin-wait first.  Ignore effect on timeout.
+      __i = _M_load_and_test_until_impl(__i, __val, true, __mo, __atime);
+      return (__i & ~_Waiter_bit) == __val;
+    }
+
+    // Returns false iff a timeout occurred.
+    template<typename _Duration>
+    _GLIBCXX_ALWAYS_INLINE bool
+    _M_load_when_equal_until(unsigned __val, memory_order __mo,
+	const chrono::time_point<std::chrono::steady_clock, _Duration>& __atime)
+    {
+      unsigned __i = _M_load(__mo);
+      if ((__i & ~_Waiter_bit) == __val)
+	return true;
+      // TODO Spin-wait first.  Ignore effect on timeout.
+      __i = _M_load_and_test_until_impl(__i, __val, true, __mo, __atime);
+      return (__i & ~_Waiter_bit) == __val;
+    }
+
+    _GLIBCXX_ALWAYS_INLINE void
+    _M_store_notify_all(unsigned __val, memory_order __mo)
+    {
+      unsigned* __futex = (unsigned *)(void *)&_M_data;
+      if (_M_data.exchange(__val, __mo) & _Waiter_bit)
+	_M_futex_notify_all(__futex);
+    }
+  };
+
+#else // ! (_GLIBCXX_HAVE_LINUX_FUTEX && ATOMIC_INT_LOCK_FREE > 1)
+
+  // If futexes are not available, use a mutex and a condvar to wait.
+  // Because we access the data only within critical sections, all accesses
+  // are sequentially consistent; thus, we satisfy any provided memory_order.
+  template <unsigned _Waiter_bit = 0x80000000>
+  class __atomic_futex_unsigned
+  {
+    typedef chrono::system_clock __clock_t;
+
+    unsigned _M_data;
+    mutex _M_mutex;
+    condition_variable _M_condvar;
+
+  public:
+    explicit
+    __atomic_futex_unsigned(unsigned __data) : _M_data(__data)
+    { }
+
+    _GLIBCXX_ALWAYS_INLINE unsigned
+    _M_load(memory_order __mo)
+    {
+      unique_lock<mutex> __lock(_M_mutex);
+      return _M_data;
+    }
+
+    _GLIBCXX_ALWAYS_INLINE unsigned
+    _M_load_when_not_equal(unsigned __val, memory_order __mo)
+    {
+      unique_lock<mutex> __lock(_M_mutex);
+      while (_M_data == __val)
+	_M_condvar.wait(__lock);
+      return _M_data;
+    }
+
+    _GLIBCXX_ALWAYS_INLINE void
+    _M_load_when_equal(unsigned __val, memory_order __mo)
+    {
+      unique_lock<mutex> __lock(_M_mutex);
+      while (_M_data != __val)
+	_M_condvar.wait(__lock);
+    }
+
+    template<typename _Rep, typename _Period>
+      _GLIBCXX_ALWAYS_INLINE bool
+      _M_load_when_equal_for(unsigned __val, memory_order __mo,
+	  const chrono::duration<_Rep, _Period>& __rtime)
+      {
+	unique_lock<mutex> __lock(_M_mutex);
+	return _M_condvar.wait_for(__lock, __rtime,
+				   [&] { return _M_data == __val;});
+      }
+
+    template<typename _Clock, typename _Duration>
+      _GLIBCXX_ALWAYS_INLINE bool
+      _M_load_when_equal_until(unsigned __val, memory_order __mo,
+	  const chrono::time_point<_Clock, _Duration>& __atime)
+      {
+	unique_lock<mutex> __lock(_M_mutex);
+	return _M_condvar.wait_until(__lock, __atime,
+				     [&] { return _M_data == __val;});
+      }
+
+    _GLIBCXX_ALWAYS_INLINE void
+    _M_store_notify_all(unsigned __val, memory_order __mo)
+    {
+      unique_lock<mutex> __lock(_M_mutex);
+      _M_data = __val;
+      _M_condvar.notify_all();
+    }
+  };
+
+#endif // _GLIBCXX_HAVE_LINUX_FUTEX && ATOMIC_INT_LOCK_FREE > 1
+#endif // _GLIBCXX_HAS_GTHREADS
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@atomic_lockfree_defines.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@atomic_lockfree_defines.h
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--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@atomic_lockfree_defines.h
@@ -0,0 +1,66 @@
+// -*- C++ -*- header.
+
+// Copyright (C) 2008-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/atomic_lockfree_defines.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{atomic}
+ */
+
+#ifndef _GLIBCXX_ATOMIC_LOCK_FREE_H
+#define _GLIBCXX_ATOMIC_LOCK_FREE_H 1
+
+#pragma GCC system_header
+
+/**
+ * @addtogroup atomics
+ * @{
+ */
+
+/**
+ * Lock-free property.
+ *
+ * 0 indicates that the types are never lock-free.
+ * 1 indicates that the types are sometimes lock-free.
+ * 2 indicates that the types are always lock-free.
+ */
+
+#if __cplusplus >= 201103L
+#define ATOMIC_BOOL_LOCK_FREE		__GCC_ATOMIC_BOOL_LOCK_FREE
+#define ATOMIC_CHAR_LOCK_FREE		__GCC_ATOMIC_CHAR_LOCK_FREE
+#define ATOMIC_WCHAR_T_LOCK_FREE	__GCC_ATOMIC_WCHAR_T_LOCK_FREE
+#ifdef _GLIBCXX_USE_CHAR8_T
+#define ATOMIC_CHAR8_T_LOCK_FREE	__GCC_ATOMIC_CHAR8_T_LOCK_FREE
+#endif
+#define ATOMIC_CHAR16_T_LOCK_FREE	__GCC_ATOMIC_CHAR16_T_LOCK_FREE
+#define ATOMIC_CHAR32_T_LOCK_FREE	__GCC_ATOMIC_CHAR32_T_LOCK_FREE
+#define ATOMIC_SHORT_LOCK_FREE		__GCC_ATOMIC_SHORT_LOCK_FREE
+#define ATOMIC_INT_LOCK_FREE		__GCC_ATOMIC_INT_LOCK_FREE
+#define ATOMIC_LONG_LOCK_FREE		__GCC_ATOMIC_LONG_LOCK_FREE
+#define ATOMIC_LLONG_LOCK_FREE		__GCC_ATOMIC_LLONG_LOCK_FREE
+#define ATOMIC_POINTER_LOCK_FREE	__GCC_ATOMIC_POINTER_LOCK_FREE
+#endif
+
+/// @} group atomics
+
+#endif
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@basic_ios.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@basic_ios.h
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@basic_ios.h
@@ -0,0 +1,518 @@
+// Iostreams base classes -*- C++ -*-
+
+// Copyright (C) 1997-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/basic_ios.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{ios}
+ */
+
+#ifndef _BASIC_IOS_H
+#define _BASIC_IOS_H 1
+
+#pragma GCC system_header
+
+#include <bits/localefwd.h>
+#include <bits/locale_classes.h>
+#include <bits/locale_facets.h>
+#include <bits/streambuf_iterator.h>
+#include <bits/move.h>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  template<typename _Facet>
+    inline const _Facet&
+    __check_facet(const _Facet* __f)
+    {
+      if (!__f)
+	__throw_bad_cast();
+      return *__f;
+    }
+
+  /**
+   *  @brief Template class basic_ios, virtual base class for all
+   *  stream classes. 
+   *  @ingroup io
+   *
+   *  @tparam _CharT  Type of character stream.
+   *  @tparam _Traits  Traits for character type, defaults to
+   *                   char_traits<_CharT>.
+   *
+   *  Most of the member functions called dispatched on stream objects
+   *  (e.g., @c std::cout.foo(bar);) are consolidated in this class.
+  */
+  template<typename _CharT, typename _Traits>
+    class basic_ios : public ios_base
+    {
+    public:
+      ///@{
+      /**
+       *  These are standard types.  They permit a standardized way of
+       *  referring to names of (or names dependent on) the template
+       *  parameters, which are specific to the implementation.
+      */
+      typedef _CharT                                 char_type;
+      typedef typename _Traits::int_type             int_type;
+      typedef typename _Traits::pos_type             pos_type;
+      typedef typename _Traits::off_type             off_type;
+      typedef _Traits                                traits_type;
+      ///@}
+
+      ///@{
+      /**
+       *  These are non-standard types.
+      */
+      typedef ctype<_CharT>                          __ctype_type;
+      typedef num_put<_CharT, ostreambuf_iterator<_CharT, _Traits> >
+						     __num_put_type;
+      typedef num_get<_CharT, istreambuf_iterator<_CharT, _Traits> >
+						     __num_get_type;
+      ///@}
+
+      // Data members:
+    protected:
+      basic_ostream<_CharT, _Traits>*                _M_tie;
+      mutable char_type                              _M_fill;
+      mutable bool                                   _M_fill_init;
+      basic_streambuf<_CharT, _Traits>*              _M_streambuf;
+
+      // Cached use_facet<ctype>, which is based on the current locale info.
+      const __ctype_type*                            _M_ctype;
+      // For ostream.
+      const __num_put_type*                          _M_num_put;
+      // For istream.
+      const __num_get_type*                          _M_num_get;
+
+    public:
+      ///@{
+      /**
+       *  @brief  The quick-and-easy status check.
+       *
+       *  This allows you to write constructs such as
+       *  <code>if (!a_stream) ...</code> and <code>while (a_stream) ...</code>
+      */
+#if __cplusplus >= 201103L
+      explicit operator bool() const
+      { return !this->fail(); }
+#else
+      operator void*() const
+      { return this->fail() ? 0 : const_cast<basic_ios*>(this); }
+#endif
+
+      bool
+      operator!() const
+      { return this->fail(); }
+      ///@}
+
+      /**
+       *  @brief  Returns the error state of the stream buffer.
+       *  @return  A bit pattern (well, isn't everything?)
+       *
+       *  See std::ios_base::iostate for the possible bit values.  Most
+       *  users will call one of the interpreting wrappers, e.g., good().
+      */
+      iostate
+      rdstate() const
+      { return _M_streambuf_state; }
+
+      /**
+       *  @brief  [Re]sets the error state.
+       *  @param  __state  The new state flag(s) to set.
+       *
+       *  See std::ios_base::iostate for the possible bit values.  Most
+       *  users will not need to pass an argument.
+      */
+      void
+      clear(iostate __state = goodbit);
+
+      /**
+       *  @brief  Sets additional flags in the error state.
+       *  @param  __state  The additional state flag(s) to set.
+       *
+       *  See std::ios_base::iostate for the possible bit values.
+      */
+      void
+      setstate(iostate __state)
+      { this->clear(this->rdstate() | __state); }
+
+      // Flip the internal state on for the proper state bits, then
+      // rethrows the propagated exception if bit also set in
+      // exceptions().
+      void
+      _M_setstate(iostate __state)
+      {
+	// 27.6.1.2.1 Common requirements.
+	// Turn this on without causing an ios::failure to be thrown.
+	_M_streambuf_state |= __state;
+	if (this->exceptions() & __state)
+	  __throw_exception_again;
+      }
+
+      /**
+       *  @brief  Fast error checking.
+       *  @return  True if no error flags are set.
+       *
+       *  A wrapper around rdstate.
+      */
+      bool
+      good() const
+      { return this->rdstate() == 0; }
+
+      /**
+       *  @brief  Fast error checking.
+       *  @return  True if the eofbit is set.
+       *
+       *  Note that other iostate flags may also be set.
+      */
+      bool
+      eof() const
+      { return (this->rdstate() & eofbit) != 0; }
+
+      /**
+       *  @brief  Fast error checking.
+       *  @return  True if either the badbit or the failbit is set.
+       *
+       *  Checking the badbit in fail() is historical practice.
+       *  Note that other iostate flags may also be set.
+      */
+      bool
+      fail() const
+      { return (this->rdstate() & (badbit | failbit)) != 0; }
+
+      /**
+       *  @brief  Fast error checking.
+       *  @return  True if the badbit is set.
+       *
+       *  Note that other iostate flags may also be set.
+      */
+      bool
+      bad() const
+      { return (this->rdstate() & badbit) != 0; }
+
+      /**
+       *  @brief  Throwing exceptions on errors.
+       *  @return  The current exceptions mask.
+       *
+       *  This changes nothing in the stream.  See the one-argument version
+       *  of exceptions(iostate) for the meaning of the return value.
+      */
+      iostate
+      exceptions() const
+      { return _M_exception; }
+
+      /**
+       *  @brief  Throwing exceptions on errors.
+       *  @param  __except  The new exceptions mask.
+       *
+       *  By default, error flags are set silently.  You can set an
+       *  exceptions mask for each stream; if a bit in the mask becomes set
+       *  in the error flags, then an exception of type
+       *  std::ios_base::failure is thrown.
+       *
+       *  If the error flag is already set when the exceptions mask is
+       *  added, the exception is immediately thrown.  Try running the
+       *  following under GCC 3.1 or later:
+       *  @code
+       *  #include <iostream>
+       *  #include <fstream>
+       *  #include <exception>
+       *
+       *  int main()
+       *  {
+       *      std::set_terminate (__gnu_cxx::__verbose_terminate_handler);
+       *
+       *      std::ifstream f ("/etc/motd");
+       *
+       *      std::cerr << "Setting badbit\n";
+       *      f.setstate (std::ios_base::badbit);
+       *
+       *      std::cerr << "Setting exception mask\n";
+       *      f.exceptions (std::ios_base::badbit);
+       *  }
+       *  @endcode
+      */
+      void
+      exceptions(iostate __except)
+      {
+        _M_exception = __except;
+        this->clear(_M_streambuf_state);
+      }
+
+      // Constructor/destructor:
+      /**
+       *  @brief  Constructor performs initialization.
+       *
+       *  The parameter is passed by derived streams.
+      */
+      explicit
+      basic_ios(basic_streambuf<_CharT, _Traits>* __sb)
+      : ios_base(), _M_tie(0), _M_fill(), _M_fill_init(false), _M_streambuf(0),
+	_M_ctype(0), _M_num_put(0), _M_num_get(0)
+      { this->init(__sb); }
+
+      /**
+       *  @brief  Empty.
+       *
+       *  The destructor does nothing.  More specifically, it does not
+       *  destroy the streambuf held by rdbuf().
+      */
+      virtual
+      ~basic_ios() { }
+
+      // Members:
+      /**
+       *  @brief  Fetches the current @e tied stream.
+       *  @return  A pointer to the tied stream, or NULL if the stream is
+       *           not tied.
+       *
+       *  A stream may be @e tied (or synchronized) to a second output
+       *  stream.  When this stream performs any I/O, the tied stream is
+       *  first flushed.  For example, @c std::cin is tied to @c std::cout.
+      */
+      basic_ostream<_CharT, _Traits>*
+      tie() const
+      { return _M_tie; }
+
+      /**
+       *  @brief  Ties this stream to an output stream.
+       *  @param  __tiestr  The output stream.
+       *  @return  The previously tied output stream, or NULL if the stream
+       *           was not tied.
+       *
+       *  This sets up a new tie; see tie() for more.
+      */
+      basic_ostream<_CharT, _Traits>*
+      tie(basic_ostream<_CharT, _Traits>* __tiestr)
+      {
+        basic_ostream<_CharT, _Traits>* __old = _M_tie;
+        _M_tie = __tiestr;
+        return __old;
+      }
+
+      /**
+       *  @brief  Accessing the underlying buffer.
+       *  @return  The current stream buffer.
+       *
+       *  This does not change the state of the stream.
+      */
+      basic_streambuf<_CharT, _Traits>*
+      rdbuf() const
+      { return _M_streambuf; }
+
+      /**
+       *  @brief  Changing the underlying buffer.
+       *  @param  __sb  The new stream buffer.
+       *  @return  The previous stream buffer.
+       *
+       *  Associates a new buffer with the current stream, and clears the
+       *  error state.
+       *
+       *  Due to historical accidents which the LWG refuses to correct, the
+       *  I/O library suffers from a design error:  this function is hidden
+       *  in derived classes by overrides of the zero-argument @c rdbuf(),
+       *  which is non-virtual for hysterical raisins.  As a result, you
+       *  must use explicit qualifications to access this function via any
+       *  derived class.  For example:
+       *
+       *  @code
+       *  std::fstream     foo;         // or some other derived type
+       *  std::streambuf*  p = .....;
+       *
+       *  foo.ios::rdbuf(p);            // ios == basic_ios<char>
+       *  @endcode
+      */
+      basic_streambuf<_CharT, _Traits>*
+      rdbuf(basic_streambuf<_CharT, _Traits>* __sb);
+
+      /**
+       *  @brief  Copies fields of __rhs into this.
+       *  @param  __rhs  The source values for the copies.
+       *  @return  Reference to this object.
+       *
+       *  All fields of __rhs are copied into this object except that rdbuf()
+       *  and rdstate() remain unchanged.  All values in the pword and iword
+       *  arrays are copied.  Before copying, each callback is invoked with
+       *  erase_event.  After copying, each (new) callback is invoked with
+       *  copyfmt_event.  The final step is to copy exceptions().
+      */
+      basic_ios&
+      copyfmt(const basic_ios& __rhs);
+
+      /**
+       *  @brief  Retrieves the @a empty character.
+       *  @return  The current fill character.
+       *
+       *  It defaults to a space (' ') in the current locale.
+      */
+      char_type
+      fill() const
+      {
+	if (!_M_fill_init)
+	  {
+	    _M_fill = this->widen(' ');
+	    _M_fill_init = true;
+	  }
+	return _M_fill;
+      }
+
+      /**
+       *  @brief  Sets a new @a empty character.
+       *  @param  __ch  The new character.
+       *  @return  The previous fill character.
+       *
+       *  The fill character is used to fill out space when P+ characters
+       *  have been requested (e.g., via setw), Q characters are actually
+       *  used, and Q<P.  It defaults to a space (' ') in the current locale.
+      */
+      char_type
+      fill(char_type __ch)
+      {
+	char_type __old = this->fill();
+	_M_fill = __ch;
+	return __old;
+      }
+
+      // Locales:
+      /**
+       *  @brief  Moves to a new locale.
+       *  @param  __loc  The new locale.
+       *  @return  The previous locale.
+       *
+       *  Calls @c ios_base::imbue(loc), and if a stream buffer is associated
+       *  with this stream, calls that buffer's @c pubimbue(loc).
+       *
+       *  Additional l10n notes are at
+       *  http://gcc.gnu.org/onlinedocs/libstdc++/manual/localization.html
+      */
+      locale
+      imbue(const locale& __loc);
+
+      /**
+       *  @brief  Squeezes characters.
+       *  @param  __c  The character to narrow.
+       *  @param  __dfault  The character to narrow.
+       *  @return  The narrowed character.
+       *
+       *  Maps a character of @c char_type to a character of @c char,
+       *  if possible.
+       *
+       *  Returns the result of
+       *  @code
+       *    std::use_facet<ctype<char_type> >(getloc()).narrow(c,dfault)
+       *  @endcode
+       *
+       *  Additional l10n notes are at
+       *  http://gcc.gnu.org/onlinedocs/libstdc++/manual/localization.html
+      */
+      char
+      narrow(char_type __c, char __dfault) const
+      { return __check_facet(_M_ctype).narrow(__c, __dfault); }
+
+      /**
+       *  @brief  Widens characters.
+       *  @param  __c  The character to widen.
+       *  @return  The widened character.
+       *
+       *  Maps a character of @c char to a character of @c char_type.
+       *
+       *  Returns the result of
+       *  @code
+       *    std::use_facet<ctype<char_type> >(getloc()).widen(c)
+       *  @endcode
+       *
+       *  Additional l10n notes are at
+       *  http://gcc.gnu.org/onlinedocs/libstdc++/manual/localization.html
+      */
+      char_type
+      widen(char __c) const
+      { return __check_facet(_M_ctype).widen(__c); }
+
+    protected:
+      // 27.4.5.1  basic_ios constructors
+      /**
+       *  @brief  Empty.
+       *
+       *  The default constructor does nothing and is not normally
+       *  accessible to users.
+      */
+      basic_ios()
+      : ios_base(), _M_tie(0), _M_fill(char_type()), _M_fill_init(false), 
+	_M_streambuf(0), _M_ctype(0), _M_num_put(0), _M_num_get(0)
+      { }
+
+      /**
+       *  @brief  All setup is performed here.
+       *
+       *  This is called from the public constructor.  It is not virtual and
+       *  cannot be redefined.
+      */
+      void
+      init(basic_streambuf<_CharT, _Traits>* __sb);
+
+#if __cplusplus >= 201103L
+      basic_ios(const basic_ios&) = delete;
+      basic_ios& operator=(const basic_ios&) = delete;
+
+      void
+      move(basic_ios& __rhs)
+      {
+	ios_base::_M_move(__rhs);
+	_M_cache_locale(_M_ios_locale);
+	this->tie(__rhs.tie(nullptr));
+	_M_fill = __rhs._M_fill;
+	_M_fill_init = __rhs._M_fill_init;
+	_M_streambuf = nullptr;
+      }
+
+      void
+      move(basic_ios&& __rhs)
+      { this->move(__rhs); }
+
+      void
+      swap(basic_ios& __rhs) noexcept
+      {
+	ios_base::_M_swap(__rhs);
+	_M_cache_locale(_M_ios_locale);
+	__rhs._M_cache_locale(__rhs._M_ios_locale);
+	std::swap(_M_tie, __rhs._M_tie);
+	std::swap(_M_fill, __rhs._M_fill);
+	std::swap(_M_fill_init, __rhs._M_fill_init);
+      }
+
+      void
+      set_rdbuf(basic_streambuf<_CharT, _Traits>* __sb)
+      { _M_streambuf = __sb; }
+#endif
+
+      void
+      _M_cache_locale(const locale& __loc);
+    };
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#include <bits/basic_ios.tcc>
+
+#endif /* _BASIC_IOS_H */
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@@ -0,0 +1,188 @@
+// basic_ios member functions -*- C++ -*-
+
+// Copyright (C) 1999-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/basic_ios.tcc
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{ios}
+ */
+
+#ifndef _BASIC_IOS_TCC
+#define _BASIC_IOS_TCC 1
+
+#pragma GCC system_header
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  template<typename _CharT, typename _Traits>
+    void
+    basic_ios<_CharT, _Traits>::clear(iostate __state)
+    {
+      if (this->rdbuf())
+	_M_streambuf_state = __state;
+      else
+	_M_streambuf_state = __state | badbit;
+      if (this->exceptions() & this->rdstate())
+	__throw_ios_failure(__N("basic_ios::clear"));
+    }
+
+  template<typename _CharT, typename _Traits>
+    basic_streambuf<_CharT, _Traits>*
+    basic_ios<_CharT, _Traits>::rdbuf(basic_streambuf<_CharT, _Traits>* __sb)
+    {
+      basic_streambuf<_CharT, _Traits>* __old = _M_streambuf;
+      _M_streambuf = __sb;
+      this->clear();
+      return __old;
+    }
+
+  template<typename _CharT, typename _Traits>
+    basic_ios<_CharT, _Traits>&
+    basic_ios<_CharT, _Traits>::copyfmt(const basic_ios& __rhs)
+    {
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 292. effects of a.copyfmt (a)
+      if (this != std::__addressof(__rhs))
+	{
+	  // Per 27.1.1, do not call imbue, yet must trash all caches
+	  // associated with imbue()
+
+	  // Alloc any new word array first, so if it fails we have "rollback".
+	  _Words* __words = (__rhs._M_word_size <= _S_local_word_size) ?
+	                     _M_local_word : new _Words[__rhs._M_word_size];
+
+	  // Bump refs before doing callbacks, for safety.
+	  _Callback_list* __cb = __rhs._M_callbacks;
+	  if (__cb)
+	    __cb->_M_add_reference();
+	  _M_call_callbacks(erase_event);
+	  if (_M_word != _M_local_word)
+	    {
+	      delete [] _M_word;
+	      _M_word = 0;
+	    }
+	  _M_dispose_callbacks();
+
+	  // NB: Don't want any added during above.
+	  _M_callbacks = __cb;
+	  for (int __i = 0; __i < __rhs._M_word_size; ++__i)
+	    __words[__i] = __rhs._M_word[__i];
+	  _M_word = __words;
+	  _M_word_size = __rhs._M_word_size;
+
+	  this->flags(__rhs.flags());
+	  this->width(__rhs.width());
+	  this->precision(__rhs.precision());
+	  this->tie(__rhs.tie());
+	  this->fill(__rhs.fill());
+	  _M_ios_locale = __rhs.getloc();
+	  _M_cache_locale(_M_ios_locale);
+
+	  _M_call_callbacks(copyfmt_event);
+
+	  // The next is required to be the last assignment.
+	  this->exceptions(__rhs.exceptions());
+	}
+      return *this;
+    }
+
+  // Locales:
+  template<typename _CharT, typename _Traits>
+    locale
+    basic_ios<_CharT, _Traits>::imbue(const locale& __loc)
+    {
+      locale __old(this->getloc());
+      ios_base::imbue(__loc);
+      _M_cache_locale(__loc);
+      if (this->rdbuf() != 0)
+	this->rdbuf()->pubimbue(__loc);
+      return __old;
+    }
+
+  template<typename _CharT, typename _Traits>
+    void
+    basic_ios<_CharT, _Traits>::init(basic_streambuf<_CharT, _Traits>* __sb)
+    {
+      // NB: This may be called more than once on the same object.
+      ios_base::_M_init();
+
+      // Cache locale data and specific facets used by iostreams.
+      _M_cache_locale(_M_ios_locale);
+
+      // NB: The 27.4.4.1 Postconditions Table specifies requirements
+      // after basic_ios::init() has been called. As part of this,
+      // fill() must return widen(' ') any time after init() has been
+      // called, which needs an imbued ctype facet of char_type to
+      // return without throwing an exception. Unfortunately,
+      // ctype<char_type> is not necessarily a required facet, so
+      // streams with char_type != [char, wchar_t] will not have it by
+      // default. Because of this, the correct value for _M_fill is
+      // constructed on the first call of fill(). That way,
+      // unformatted input and output with non-required basic_ios
+      // instantiations is possible even without imbuing the expected
+      // ctype<char_type> facet.
+      _M_fill = _CharT();
+      _M_fill_init = false;
+
+      _M_tie = 0;
+      _M_exception = goodbit;
+      _M_streambuf = __sb;
+      _M_streambuf_state = __sb ? goodbit : badbit;
+    }
+
+  template<typename _CharT, typename _Traits>
+    void
+    basic_ios<_CharT, _Traits>::_M_cache_locale(const locale& __loc)
+    {
+      if (__builtin_expect(has_facet<__ctype_type>(__loc), true))
+	_M_ctype = std::__addressof(use_facet<__ctype_type>(__loc));
+      else
+	_M_ctype = 0;
+
+      if (__builtin_expect(has_facet<__num_put_type>(__loc), true))
+	_M_num_put = std::__addressof(use_facet<__num_put_type>(__loc));
+      else
+	_M_num_put = 0;
+
+      if (__builtin_expect(has_facet<__num_get_type>(__loc), true))
+	_M_num_get = std::__addressof(use_facet<__num_get_type>(__loc));
+      else
+	_M_num_get = 0;
+    }
+
+  // Inhibit implicit instantiations for required instantiations,
+  // which are defined via explicit instantiations elsewhere.
+#if _GLIBCXX_EXTERN_TEMPLATE
+  extern template class basic_ios<char>;
+
+#ifdef _GLIBCXX_USE_WCHAR_T
+  extern template class basic_ios<wchar_t>;
+#endif
+#endif
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif
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@@ -0,0 +1,4382 @@
+// Components for manipulating sequences of characters -*- C++ -*-
+
+// Copyright (C) 1997-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/basic_string.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{string}
+ */
+
+//
+// ISO C++ 14882: 21 Strings library
+//
+
+#ifndef _BASIC_STRING_H
+#define _BASIC_STRING_H 1
+
+#pragma GCC system_header
+
+#include <ext/alloc_traits.h>
+#include <debug/debug.h>
+
+#if __cplusplus >= 201103L
+#include <initializer_list>
+#endif
+
+#if __cplusplus >= 201703L
+# include <string_view>
+#endif
+
+#if ! _GLIBCXX_USE_CXX11_ABI
+# include "cow_string.h"
+#else
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+_GLIBCXX_BEGIN_NAMESPACE_CXX11
+
+#ifdef __cpp_lib_is_constant_evaluated
+// Support P0980R1 in C++20.
+# define __cpp_lib_constexpr_string 201907L
+#elif __cplusplus >= 201703L && _GLIBCXX_HAVE_IS_CONSTANT_EVALUATED
+// Support P0426R1 changes to char_traits in C++17.
+# define __cpp_lib_constexpr_string 201611L
+#endif
+
+  /**
+   *  @class basic_string basic_string.h <string>
+   *  @brief  Managing sequences of characters and character-like objects.
+   *
+   *  @ingroup strings
+   *  @ingroup sequences
+   *
+   *  @tparam _CharT  Type of character
+   *  @tparam _Traits  Traits for character type, defaults to
+   *                   char_traits<_CharT>.
+   *  @tparam _Alloc  Allocator type, defaults to allocator<_CharT>.
+   *
+   *  Meets the requirements of a <a href="tables.html#65">container</a>, a
+   *  <a href="tables.html#66">reversible container</a>, and a
+   *  <a href="tables.html#67">sequence</a>.  Of the
+   *  <a href="tables.html#68">optional sequence requirements</a>, only
+   *  @c push_back, @c at, and @c %array access are supported.
+   */
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    class basic_string
+    {
+      typedef typename __gnu_cxx::__alloc_traits<_Alloc>::template
+	rebind<_CharT>::other _Char_alloc_type;
+
+#if __cpp_lib_constexpr_string < 201907L
+      typedef __gnu_cxx::__alloc_traits<_Char_alloc_type> _Alloc_traits;
+#else
+      template<typename _Traits2, typename _Dummy_for_PR85282>
+	struct _Alloc_traits_impl : __gnu_cxx::__alloc_traits<_Char_alloc_type>
+	{
+	  typedef __gnu_cxx::__alloc_traits<_Char_alloc_type> _Base;
+
+	  [[__gnu__::__always_inline__]]
+	  static constexpr typename _Base::pointer
+	  allocate(_Char_alloc_type& __a, typename _Base::size_type __n)
+	  {
+	    pointer __p = _Base::allocate(__a, __n);
+	    if (std::is_constant_evaluated())
+	      // Begin the lifetime of characters in allocated storage.
+	      for (size_type __i = 0; __i < __n; ++__i)
+		std::construct_at(__builtin_addressof(__p[__i]));
+	    return __p;
+	  }
+	};
+
+      template<typename _Dummy_for_PR85282>
+	struct _Alloc_traits_impl<char_traits<_CharT>, _Dummy_for_PR85282>
+	: __gnu_cxx::__alloc_traits<_Char_alloc_type>
+	{
+	  // std::char_traits begins the lifetime of characters.
+	};
+
+      using _Alloc_traits = _Alloc_traits_impl<_Traits, void>;
+#endif
+
+      // Types:
+    public:
+      typedef _Traits					traits_type;
+      typedef typename _Traits::char_type		value_type;
+      typedef _Char_alloc_type				allocator_type;
+      typedef typename _Alloc_traits::size_type		size_type;
+      typedef typename _Alloc_traits::difference_type	difference_type;
+      typedef typename _Alloc_traits::reference		reference;
+      typedef typename _Alloc_traits::const_reference	const_reference;
+      typedef typename _Alloc_traits::pointer		pointer;
+      typedef typename _Alloc_traits::const_pointer	const_pointer;
+      typedef __gnu_cxx::__normal_iterator<pointer, basic_string>  iterator;
+      typedef __gnu_cxx::__normal_iterator<const_pointer, basic_string>
+							const_iterator;
+      typedef std::reverse_iterator<const_iterator>	const_reverse_iterator;
+      typedef std::reverse_iterator<iterator>		reverse_iterator;
+
+      ///  Value returned by various member functions when they fail.
+      static const size_type	npos = static_cast<size_type>(-1);
+
+    protected:
+      // type used for positions in insert, erase etc.
+#if __cplusplus < 201103L
+      typedef iterator __const_iterator;
+#else
+      typedef const_iterator __const_iterator;
+#endif
+
+    private:
+#if __cplusplus >= 201703L
+      // A helper type for avoiding boiler-plate.
+      typedef basic_string_view<_CharT, _Traits> __sv_type;
+
+      template<typename _Tp, typename _Res>
+	using _If_sv = enable_if_t<
+	  __and_<is_convertible<const _Tp&, __sv_type>,
+		 __not_<is_convertible<const _Tp*, const basic_string*>>,
+		 __not_<is_convertible<const _Tp&, const _CharT*>>>::value,
+	  _Res>;
+
+      // Allows an implicit conversion to __sv_type.
+      _GLIBCXX20_CONSTEXPR
+      static __sv_type
+      _S_to_string_view(__sv_type __svt) noexcept
+      { return __svt; }
+
+      // Wraps a string_view by explicit conversion and thus
+      // allows to add an internal constructor that does not
+      // participate in overload resolution when a string_view
+      // is provided.
+      struct __sv_wrapper
+      {
+	_GLIBCXX20_CONSTEXPR explicit
+	__sv_wrapper(__sv_type __sv) noexcept : _M_sv(__sv) { }
+
+	__sv_type _M_sv;
+      };
+
+      /**
+       *  @brief  Only internally used: Construct string from a string view
+       *          wrapper.
+       *  @param  __svw  string view wrapper.
+       *  @param  __a  Allocator to use.
+       */
+      _GLIBCXX20_CONSTEXPR
+      explicit
+      basic_string(__sv_wrapper __svw, const _Alloc& __a)
+      : basic_string(__svw._M_sv.data(), __svw._M_sv.size(), __a) { }
+#endif
+
+      // Use empty-base optimization: http://www.cantrip.org/emptyopt.html
+      struct _Alloc_hider : allocator_type // TODO check __is_final
+      {
+#if __cplusplus < 201103L
+	_Alloc_hider(pointer __dat, const _Alloc& __a = _Alloc())
+	: allocator_type(__a), _M_p(__dat) { }
+#else
+	_GLIBCXX20_CONSTEXPR
+	_Alloc_hider(pointer __dat, const _Alloc& __a)
+	: allocator_type(__a), _M_p(__dat) { }
+
+	_GLIBCXX20_CONSTEXPR
+	_Alloc_hider(pointer __dat, _Alloc&& __a = _Alloc())
+	: allocator_type(std::move(__a)), _M_p(__dat) { }
+#endif
+
+	pointer _M_p; // The actual data.
+      };
+
+      _Alloc_hider	_M_dataplus;
+      size_type		_M_string_length;
+
+      enum { _S_local_capacity = 15 / sizeof(_CharT) };
+
+      union
+      {
+	_CharT           _M_local_buf[_S_local_capacity + 1];
+	size_type        _M_allocated_capacity;
+      };
+
+      _GLIBCXX20_CONSTEXPR
+      void
+      _M_data(pointer __p)
+      { _M_dataplus._M_p = __p; }
+
+      _GLIBCXX20_CONSTEXPR
+      void
+      _M_length(size_type __length)
+      { _M_string_length = __length; }
+
+      _GLIBCXX20_CONSTEXPR
+      pointer
+      _M_data() const
+      { return _M_dataplus._M_p; }
+
+      _GLIBCXX20_CONSTEXPR
+      pointer
+      _M_local_data()
+      {
+#if __cplusplus >= 201103L
+	return std::pointer_traits<pointer>::pointer_to(*_M_local_buf);
+#else
+	return pointer(_M_local_buf);
+#endif
+      }
+
+      _GLIBCXX20_CONSTEXPR
+      const_pointer
+      _M_local_data() const
+      {
+#if __cplusplus >= 201103L
+	return std::pointer_traits<const_pointer>::pointer_to(*_M_local_buf);
+#else
+	return const_pointer(_M_local_buf);
+#endif
+      }
+
+      _GLIBCXX20_CONSTEXPR
+      void
+      _M_capacity(size_type __capacity)
+      { _M_allocated_capacity = __capacity; }
+
+      _GLIBCXX20_CONSTEXPR
+      void
+      _M_set_length(size_type __n)
+      {
+	_M_length(__n);
+	traits_type::assign(_M_data()[__n], _CharT());
+      }
+
+      _GLIBCXX20_CONSTEXPR
+      bool
+      _M_is_local() const
+      { return _M_data() == _M_local_data(); }
+
+      // Create & Destroy
+      _GLIBCXX20_CONSTEXPR
+      pointer
+      _M_create(size_type&, size_type);
+
+      _GLIBCXX20_CONSTEXPR
+      void
+      _M_dispose()
+      {
+	if (!_M_is_local())
+	  _M_destroy(_M_allocated_capacity);
+      }
+
+      _GLIBCXX20_CONSTEXPR
+      void
+      _M_destroy(size_type __size) throw()
+      { _Alloc_traits::deallocate(_M_get_allocator(), _M_data(), __size + 1); }
+
+#if __cplusplus < 201103L || defined _GLIBCXX_DEFINING_STRING_INSTANTIATIONS
+      // _M_construct_aux is used to implement the 21.3.1 para 15 which
+      // requires special behaviour if _InIterator is an integral type
+      template<typename _InIterator>
+        void
+        _M_construct_aux(_InIterator __beg, _InIterator __end,
+			 std::__false_type)
+	{
+          typedef typename iterator_traits<_InIterator>::iterator_category _Tag;
+          _M_construct(__beg, __end, _Tag());
+	}
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 438. Ambiguity in the "do the right thing" clause
+      template<typename _Integer>
+        void
+        _M_construct_aux(_Integer __beg, _Integer __end, std::__true_type)
+	{ _M_construct_aux_2(static_cast<size_type>(__beg), __end); }
+
+      void
+      _M_construct_aux_2(size_type __req, _CharT __c)
+      { _M_construct(__req, __c); }
+#endif
+
+      // For Input Iterators, used in istreambuf_iterators, etc.
+      template<typename _InIterator>
+	_GLIBCXX20_CONSTEXPR
+        void
+        _M_construct(_InIterator __beg, _InIterator __end,
+		     std::input_iterator_tag);
+
+      // For forward_iterators up to random_access_iterators, used for
+      // string::iterator, _CharT*, etc.
+      template<typename _FwdIterator>
+	_GLIBCXX20_CONSTEXPR
+        void
+        _M_construct(_FwdIterator __beg, _FwdIterator __end,
+		     std::forward_iterator_tag);
+
+      _GLIBCXX20_CONSTEXPR
+      void
+      _M_construct(size_type __req, _CharT __c);
+
+      _GLIBCXX20_CONSTEXPR
+      allocator_type&
+      _M_get_allocator()
+      { return _M_dataplus; }
+
+      _GLIBCXX20_CONSTEXPR
+      const allocator_type&
+      _M_get_allocator() const
+      { return _M_dataplus; }
+
+      // Ensure that _M_local_buf is the active member of the union.
+      __attribute__((__always_inline__))
+      _GLIBCXX14_CONSTEXPR
+      pointer
+      _M_use_local_data() _GLIBCXX_NOEXCEPT
+      {
+#if __cpp_lib_is_constant_evaluated
+	if (std::is_constant_evaluated())
+	  for (_CharT& __c : _M_local_buf)
+	    __c = _CharT();
+#endif
+	return _M_local_data();
+      }
+
+    private:
+
+#ifdef _GLIBCXX_DISAMBIGUATE_REPLACE_INST
+      // The explicit instantiations in misc-inst.cc require this due to
+      // https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64063
+      template<typename _Tp, bool _Requires =
+	       !__are_same<_Tp, _CharT*>::__value
+	       && !__are_same<_Tp, const _CharT*>::__value
+	       && !__are_same<_Tp, iterator>::__value
+	       && !__are_same<_Tp, const_iterator>::__value>
+	struct __enable_if_not_native_iterator
+	{ typedef basic_string& __type; };
+      template<typename _Tp>
+	struct __enable_if_not_native_iterator<_Tp, false> { };
+#endif
+
+      _GLIBCXX20_CONSTEXPR
+      size_type
+      _M_check(size_type __pos, const char* __s) const
+      {
+	if (__pos > this->size())
+	  __throw_out_of_range_fmt(__N("%s: __pos (which is %zu) > "
+				       "this->size() (which is %zu)"),
+				   __s, __pos, this->size());
+	return __pos;
+      }
+
+      _GLIBCXX20_CONSTEXPR
+      void
+      _M_check_length(size_type __n1, size_type __n2, const char* __s) const
+      {
+	if (this->max_size() - (this->size() - __n1) < __n2)
+	  __throw_length_error(__N(__s));
+      }
+
+
+      // NB: _M_limit doesn't check for a bad __pos value.
+      _GLIBCXX20_CONSTEXPR
+      size_type
+      _M_limit(size_type __pos, size_type __off) const _GLIBCXX_NOEXCEPT
+      {
+	const bool __testoff =  __off < this->size() - __pos;
+	return __testoff ? __off : this->size() - __pos;
+      }
+
+      // True if _Rep and source do not overlap.
+      bool
+      _M_disjunct(const _CharT* __s) const _GLIBCXX_NOEXCEPT
+      {
+	return (less<const _CharT*>()(__s, _M_data())
+		|| less<const _CharT*>()(_M_data() + this->size(), __s));
+      }
+
+      // When __n = 1 way faster than the general multichar
+      // traits_type::copy/move/assign.
+      _GLIBCXX20_CONSTEXPR
+      static void
+      _S_copy(_CharT* __d, const _CharT* __s, size_type __n)
+      {
+	if (__n == 1)
+	  traits_type::assign(*__d, *__s);
+	else
+	  traits_type::copy(__d, __s, __n);
+      }
+
+      _GLIBCXX20_CONSTEXPR
+      static void
+      _S_move(_CharT* __d, const _CharT* __s, size_type __n)
+      {
+	if (__n == 1)
+	  traits_type::assign(*__d, *__s);
+	else
+	  traits_type::move(__d, __s, __n);
+      }
+
+      _GLIBCXX20_CONSTEXPR
+      static void
+      _S_assign(_CharT* __d, size_type __n, _CharT __c)
+      {
+	if (__n == 1)
+	  traits_type::assign(*__d, __c);
+	else
+	  traits_type::assign(__d, __n, __c);
+      }
+
+      // _S_copy_chars is a separate template to permit specialization
+      // to optimize for the common case of pointers as iterators.
+      template<class _Iterator>
+	_GLIBCXX20_CONSTEXPR
+        static void
+        _S_copy_chars(_CharT* __p, _Iterator __k1, _Iterator __k2)
+        {
+	  for (; __k1 != __k2; ++__k1, (void)++__p)
+	    traits_type::assign(*__p, *__k1); // These types are off.
+	}
+
+      _GLIBCXX20_CONSTEXPR
+      static void
+      _S_copy_chars(_CharT* __p, iterator __k1, iterator __k2) _GLIBCXX_NOEXCEPT
+      { _S_copy_chars(__p, __k1.base(), __k2.base()); }
+
+      _GLIBCXX20_CONSTEXPR
+      static void
+      _S_copy_chars(_CharT* __p, const_iterator __k1, const_iterator __k2)
+      _GLIBCXX_NOEXCEPT
+      { _S_copy_chars(__p, __k1.base(), __k2.base()); }
+
+      _GLIBCXX20_CONSTEXPR
+      static void
+      _S_copy_chars(_CharT* __p, _CharT* __k1, _CharT* __k2) _GLIBCXX_NOEXCEPT
+      { _S_copy(__p, __k1, __k2 - __k1); }
+
+      _GLIBCXX20_CONSTEXPR
+      static void
+      _S_copy_chars(_CharT* __p, const _CharT* __k1, const _CharT* __k2)
+      _GLIBCXX_NOEXCEPT
+      { _S_copy(__p, __k1, __k2 - __k1); }
+
+      _GLIBCXX20_CONSTEXPR
+      static int
+      _S_compare(size_type __n1, size_type __n2) _GLIBCXX_NOEXCEPT
+      {
+	const difference_type __d = difference_type(__n1 - __n2);
+
+	if (__d > __gnu_cxx::__numeric_traits<int>::__max)
+	  return __gnu_cxx::__numeric_traits<int>::__max;
+	else if (__d < __gnu_cxx::__numeric_traits<int>::__min)
+	  return __gnu_cxx::__numeric_traits<int>::__min;
+	else
+	  return int(__d);
+      }
+
+      _GLIBCXX20_CONSTEXPR
+      void
+      _M_assign(const basic_string&);
+
+      _GLIBCXX20_CONSTEXPR
+      void
+      _M_mutate(size_type __pos, size_type __len1, const _CharT* __s,
+		size_type __len2);
+
+      _GLIBCXX20_CONSTEXPR
+      void
+      _M_erase(size_type __pos, size_type __n);
+
+    public:
+      // Construct/copy/destroy:
+      // NB: We overload ctors in some cases instead of using default
+      // arguments, per 17.4.4.4 para. 2 item 2.
+
+      /**
+       *  @brief  Default constructor creates an empty string.
+       */
+      _GLIBCXX20_CONSTEXPR
+      basic_string()
+      _GLIBCXX_NOEXCEPT_IF(is_nothrow_default_constructible<_Alloc>::value)
+      : _M_dataplus(_M_local_data())
+      {
+	_M_use_local_data();
+	_M_set_length(0);
+      }
+
+      /**
+       *  @brief  Construct an empty string using allocator @a a.
+       */
+      _GLIBCXX20_CONSTEXPR
+      explicit
+      basic_string(const _Alloc& __a) _GLIBCXX_NOEXCEPT
+      : _M_dataplus(_M_local_data(), __a)
+      {
+	_M_use_local_data();
+	_M_set_length(0);
+      }
+
+      /**
+       *  @brief  Construct string with copy of value of @a __str.
+       *  @param  __str  Source string.
+       */
+      _GLIBCXX20_CONSTEXPR
+      basic_string(const basic_string& __str)
+      : _M_dataplus(_M_local_data(),
+		    _Alloc_traits::_S_select_on_copy(__str._M_get_allocator()))
+      {
+	_M_construct(__str._M_data(), __str._M_data() + __str.length(),
+		     std::forward_iterator_tag());
+      }
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 2583. no way to supply an allocator for basic_string(str, pos)
+      /**
+       *  @brief  Construct string as copy of a substring.
+       *  @param  __str  Source string.
+       *  @param  __pos  Index of first character to copy from.
+       *  @param  __a  Allocator to use.
+       */
+      _GLIBCXX20_CONSTEXPR
+      basic_string(const basic_string& __str, size_type __pos,
+		   const _Alloc& __a = _Alloc())
+      : _M_dataplus(_M_local_data(), __a)
+      {
+	const _CharT* __start = __str._M_data()
+	  + __str._M_check(__pos, "basic_string::basic_string");
+	_M_construct(__start, __start + __str._M_limit(__pos, npos),
+		     std::forward_iterator_tag());
+      }
+
+      /**
+       *  @brief  Construct string as copy of a substring.
+       *  @param  __str  Source string.
+       *  @param  __pos  Index of first character to copy from.
+       *  @param  __n  Number of characters to copy.
+       */
+      _GLIBCXX20_CONSTEXPR
+      basic_string(const basic_string& __str, size_type __pos,
+		   size_type __n)
+      : _M_dataplus(_M_local_data())
+      {
+	const _CharT* __start = __str._M_data()
+	  + __str._M_check(__pos, "basic_string::basic_string");
+	_M_construct(__start, __start + __str._M_limit(__pos, __n),
+		     std::forward_iterator_tag());
+      }
+
+      /**
+       *  @brief  Construct string as copy of a substring.
+       *  @param  __str  Source string.
+       *  @param  __pos  Index of first character to copy from.
+       *  @param  __n  Number of characters to copy.
+       *  @param  __a  Allocator to use.
+       */
+      _GLIBCXX20_CONSTEXPR
+      basic_string(const basic_string& __str, size_type __pos,
+		   size_type __n, const _Alloc& __a)
+      : _M_dataplus(_M_local_data(), __a)
+      {
+	const _CharT* __start
+	  = __str._M_data() + __str._M_check(__pos, "string::string");
+	_M_construct(__start, __start + __str._M_limit(__pos, __n),
+		     std::forward_iterator_tag());
+      }
+
+      /**
+       *  @brief  Construct string initialized by a character %array.
+       *  @param  __s  Source character %array.
+       *  @param  __n  Number of characters to copy.
+       *  @param  __a  Allocator to use (default is default allocator).
+       *
+       *  NB: @a __s must have at least @a __n characters, &apos;\\0&apos;
+       *  has no special meaning.
+       */
+      _GLIBCXX20_CONSTEXPR
+      basic_string(const _CharT* __s, size_type __n,
+		   const _Alloc& __a = _Alloc())
+      : _M_dataplus(_M_local_data(), __a)
+      {
+	// NB: Not required, but considered best practice.
+	if (__s == 0 && __n > 0)
+	  std::__throw_logic_error(__N("basic_string: "
+				       "construction from null is not valid"));
+	_M_construct(__s, __s + __n, std::forward_iterator_tag());
+      }
+
+      /**
+       *  @brief  Construct string as copy of a C string.
+       *  @param  __s  Source C string.
+       *  @param  __a  Allocator to use (default is default allocator).
+       */
+#if __cpp_deduction_guides && ! defined _GLIBCXX_DEFINING_STRING_INSTANTIATIONS
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 3076. basic_string CTAD ambiguity
+      template<typename = _RequireAllocator<_Alloc>>
+#endif
+      _GLIBCXX20_CONSTEXPR
+      basic_string(const _CharT* __s, const _Alloc& __a = _Alloc())
+      : _M_dataplus(_M_local_data(), __a)
+      {
+	// NB: Not required, but considered best practice.
+	if (__s == 0)
+	  std::__throw_logic_error(__N("basic_string: "
+				       "construction from null is not valid"));
+	const _CharT* __end = __s + traits_type::length(__s);
+	_M_construct(__s, __end, forward_iterator_tag());
+      }
+
+      /**
+       *  @brief  Construct string as multiple characters.
+       *  @param  __n  Number of characters.
+       *  @param  __c  Character to use.
+       *  @param  __a  Allocator to use (default is default allocator).
+       */
+#if __cpp_deduction_guides && ! defined _GLIBCXX_DEFINING_STRING_INSTANTIATIONS
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 3076. basic_string CTAD ambiguity
+      template<typename = _RequireAllocator<_Alloc>>
+#endif
+      _GLIBCXX20_CONSTEXPR
+      basic_string(size_type __n, _CharT __c, const _Alloc& __a = _Alloc())
+      : _M_dataplus(_M_local_data(), __a)
+      { _M_construct(__n, __c); }
+
+#if __cplusplus >= 201103L
+      /**
+       *  @brief  Move construct string.
+       *  @param  __str  Source string.
+       *
+       *  The newly-created string contains the exact contents of @a __str.
+       *  @a __str is a valid, but unspecified string.
+       */
+      _GLIBCXX20_CONSTEXPR
+      basic_string(basic_string&& __str) noexcept
+      : _M_dataplus(_M_local_data(), std::move(__str._M_get_allocator()))
+      {
+	if (__str._M_is_local())
+	  {
+	    traits_type::copy(_M_local_buf, __str._M_local_buf,
+			      __str.length() + 1);
+	  }
+	else
+	  {
+	    _M_data(__str._M_data());
+	    _M_capacity(__str._M_allocated_capacity);
+	  }
+
+	// Must use _M_length() here not _M_set_length() because
+	// basic_stringbuf relies on writing into unallocated capacity so
+	// we mess up the contents if we put a '\0' in the string.
+	_M_length(__str.length());
+	__str._M_data(__str._M_local_data());
+	__str._M_set_length(0);
+      }
+
+      /**
+       *  @brief  Construct string from an initializer %list.
+       *  @param  __l  std::initializer_list of characters.
+       *  @param  __a  Allocator to use (default is default allocator).
+       */
+      _GLIBCXX20_CONSTEXPR
+      basic_string(initializer_list<_CharT> __l, const _Alloc& __a = _Alloc())
+      : _M_dataplus(_M_local_data(), __a)
+      { _M_construct(__l.begin(), __l.end(), std::forward_iterator_tag()); }
+
+      _GLIBCXX20_CONSTEXPR
+      basic_string(const basic_string& __str, const _Alloc& __a)
+      : _M_dataplus(_M_local_data(), __a)
+      { _M_construct(__str.begin(), __str.end(), std::forward_iterator_tag()); }
+
+      _GLIBCXX20_CONSTEXPR
+      basic_string(basic_string&& __str, const _Alloc& __a)
+      noexcept(_Alloc_traits::_S_always_equal())
+      : _M_dataplus(_M_local_data(), __a)
+      {
+	if (__str._M_is_local())
+	  {
+	    traits_type::copy(_M_local_buf, __str._M_local_buf,
+			      __str.length() + 1);
+	    _M_length(__str.length());
+	    __str._M_set_length(0);
+	  }
+	else if (_Alloc_traits::_S_always_equal()
+	    || __str.get_allocator() == __a)
+	  {
+	    _M_data(__str._M_data());
+	    _M_length(__str.length());
+	    _M_capacity(__str._M_allocated_capacity);
+	    __str._M_data(__str._M_local_buf);
+	    __str._M_set_length(0);
+	  }
+	else
+	  _M_construct(__str.begin(), __str.end(), std::forward_iterator_tag());
+      }
+#endif // C++11
+
+#if __cplusplus >= 202100L
+      basic_string(nullptr_t) = delete;
+      basic_string& operator=(nullptr_t) = delete;
+#endif // C++23
+
+      /**
+       *  @brief  Construct string as copy of a range.
+       *  @param  __beg  Start of range.
+       *  @param  __end  End of range.
+       *  @param  __a  Allocator to use (default is default allocator).
+       */
+#if __cplusplus >= 201103L
+      template<typename _InputIterator,
+	       typename = std::_RequireInputIter<_InputIterator>>
+#else
+      template<typename _InputIterator>
+#endif
+	_GLIBCXX20_CONSTEXPR
+        basic_string(_InputIterator __beg, _InputIterator __end,
+		     const _Alloc& __a = _Alloc())
+	: _M_dataplus(_M_local_data(), __a)
+	{
+#if __cplusplus >= 201103L
+	  _M_construct(__beg, __end, std::__iterator_category(__beg));
+#else
+	  typedef typename std::__is_integer<_InputIterator>::__type _Integral;
+	  _M_construct_aux(__beg, __end, _Integral());
+#endif
+	}
+
+#if __cplusplus >= 201703L
+      /**
+       *  @brief  Construct string from a substring of a string_view.
+       *  @param  __t   Source object convertible to string view.
+       *  @param  __pos The index of the first character to copy from __t.
+       *  @param  __n   The number of characters to copy from __t.
+       *  @param  __a   Allocator to use.
+       */
+      template<typename _Tp,
+	       typename = enable_if_t<is_convertible_v<const _Tp&, __sv_type>>>
+	_GLIBCXX20_CONSTEXPR
+	basic_string(const _Tp& __t, size_type __pos, size_type __n,
+		     const _Alloc& __a = _Alloc())
+	: basic_string(_S_to_string_view(__t).substr(__pos, __n), __a) { }
+
+      /**
+       *  @brief  Construct string from a string_view.
+       *  @param  __t  Source object convertible to string view.
+       *  @param  __a  Allocator to use (default is default allocator).
+       */
+      template<typename _Tp, typename = _If_sv<_Tp, void>>
+	_GLIBCXX20_CONSTEXPR
+	explicit
+	basic_string(const _Tp& __t, const _Alloc& __a = _Alloc())
+	: basic_string(__sv_wrapper(_S_to_string_view(__t)), __a) { }
+#endif // C++17
+
+      /**
+       *  @brief  Destroy the string instance.
+       */
+      _GLIBCXX20_CONSTEXPR
+      ~basic_string()
+      { _M_dispose(); }
+
+      /**
+       *  @brief  Assign the value of @a str to this string.
+       *  @param  __str  Source string.
+       */
+      _GLIBCXX20_CONSTEXPR
+      basic_string&
+      operator=(const basic_string& __str)
+      {
+	return this->assign(__str);
+      }
+
+      /**
+       *  @brief  Copy contents of @a s into this string.
+       *  @param  __s  Source null-terminated string.
+       */
+      _GLIBCXX20_CONSTEXPR
+      basic_string&
+      operator=(const _CharT* __s)
+      { return this->assign(__s); }
+
+      /**
+       *  @brief  Set value to string of length 1.
+       *  @param  __c  Source character.
+       *
+       *  Assigning to a character makes this string length 1 and
+       *  (*this)[0] == @a c.
+       */
+      _GLIBCXX20_CONSTEXPR
+      basic_string&
+      operator=(_CharT __c)
+      {
+	this->assign(1, __c);
+	return *this;
+      }
+
+#if __cplusplus >= 201103L
+      /**
+       *  @brief  Move assign the value of @a str to this string.
+       *  @param  __str  Source string.
+       *
+       *  The contents of @a str are moved into this string (without copying).
+       *  @a str is a valid, but unspecified string.
+       */
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 2063. Contradictory requirements for string move assignment
+      _GLIBCXX20_CONSTEXPR
+      basic_string&
+      operator=(basic_string&& __str)
+      noexcept(_Alloc_traits::_S_nothrow_move())
+      {
+	if (!_M_is_local() && _Alloc_traits::_S_propagate_on_move_assign()
+	    && !_Alloc_traits::_S_always_equal()
+	    && _M_get_allocator() != __str._M_get_allocator())
+	  {
+	    // Destroy existing storage before replacing allocator.
+	    _M_destroy(_M_allocated_capacity);
+	    _M_data(_M_local_data());
+	    _M_set_length(0);
+	  }
+	// Replace allocator if POCMA is true.
+	std::__alloc_on_move(_M_get_allocator(), __str._M_get_allocator());
+
+	if (__str._M_is_local())
+	  {
+	    // We've always got room for a short string, just copy it
+	    // (unless this is a self-move, because that would violate the
+	    // char_traits::copy precondition that the ranges don't overlap).
+	    if (__builtin_expect(std::__addressof(__str) != this, true))
+	      {
+		if (__str.size())
+		  this->_S_copy(_M_data(), __str._M_data(), __str.size());
+		_M_set_length(__str.size());
+	      }
+	  }
+	else if (_Alloc_traits::_S_propagate_on_move_assign()
+	    || _Alloc_traits::_S_always_equal()
+	    || _M_get_allocator() == __str._M_get_allocator())
+	  {
+	    // Just move the allocated pointer, our allocator can free it.
+	    pointer __data = nullptr;
+	    size_type __capacity;
+	    if (!_M_is_local())
+	      {
+		if (_Alloc_traits::_S_always_equal())
+		  {
+		    // __str can reuse our existing storage.
+		    __data = _M_data();
+		    __capacity = _M_allocated_capacity;
+		  }
+		else // __str can't use it, so free it.
+		  _M_destroy(_M_allocated_capacity);
+	      }
+
+	    _M_data(__str._M_data());
+	    _M_length(__str.length());
+	    _M_capacity(__str._M_allocated_capacity);
+	    if (__data)
+	      {
+		__str._M_data(__data);
+		__str._M_capacity(__capacity);
+	      }
+	    else
+	      __str._M_data(__str._M_local_buf);
+	  }
+	else // Need to do a deep copy
+	  assign(__str);
+	__str.clear();
+	return *this;
+      }
+
+      /**
+       *  @brief  Set value to string constructed from initializer %list.
+       *  @param  __l  std::initializer_list.
+       */
+      _GLIBCXX20_CONSTEXPR
+      basic_string&
+      operator=(initializer_list<_CharT> __l)
+      {
+	this->assign(__l.begin(), __l.size());
+	return *this;
+      }
+#endif // C++11
+
+#if __cplusplus >= 201703L
+      /**
+       *  @brief  Set value to string constructed from a string_view.
+       *  @param  __svt  An object convertible to string_view.
+       */
+     template<typename _Tp>
+       _GLIBCXX20_CONSTEXPR
+       _If_sv<_Tp, basic_string&>
+       operator=(const _Tp& __svt)
+       { return this->assign(__svt); }
+
+      /**
+       *  @brief  Convert to a string_view.
+       *  @return A string_view.
+       */
+      _GLIBCXX20_CONSTEXPR
+      operator __sv_type() const noexcept
+      { return __sv_type(data(), size()); }
+#endif // C++17
+
+      // Iterators:
+      /**
+       *  Returns a read/write iterator that points to the first character in
+       *  the %string.
+       */
+      _GLIBCXX20_CONSTEXPR
+      iterator
+      begin() _GLIBCXX_NOEXCEPT
+      { return iterator(_M_data()); }
+
+      /**
+       *  Returns a read-only (constant) iterator that points to the first
+       *  character in the %string.
+       */
+      _GLIBCXX20_CONSTEXPR
+      const_iterator
+      begin() const _GLIBCXX_NOEXCEPT
+      { return const_iterator(_M_data()); }
+
+      /**
+       *  Returns a read/write iterator that points one past the last
+       *  character in the %string.
+       */
+      _GLIBCXX20_CONSTEXPR
+      iterator
+      end() _GLIBCXX_NOEXCEPT
+      { return iterator(_M_data() + this->size()); }
+
+      /**
+       *  Returns a read-only (constant) iterator that points one past the
+       *  last character in the %string.
+       */
+      _GLIBCXX20_CONSTEXPR
+      const_iterator
+      end() const _GLIBCXX_NOEXCEPT
+      { return const_iterator(_M_data() + this->size()); }
+
+      /**
+       *  Returns a read/write reverse iterator that points to the last
+       *  character in the %string.  Iteration is done in reverse element
+       *  order.
+       */
+      _GLIBCXX20_CONSTEXPR
+      reverse_iterator
+      rbegin() _GLIBCXX_NOEXCEPT
+      { return reverse_iterator(this->end()); }
+
+      /**
+       *  Returns a read-only (constant) reverse iterator that points
+       *  to the last character in the %string.  Iteration is done in
+       *  reverse element order.
+       */
+      _GLIBCXX20_CONSTEXPR
+      const_reverse_iterator
+      rbegin() const _GLIBCXX_NOEXCEPT
+      { return const_reverse_iterator(this->end()); }
+
+      /**
+       *  Returns a read/write reverse iterator that points to one before the
+       *  first character in the %string.  Iteration is done in reverse
+       *  element order.
+       */
+      _GLIBCXX20_CONSTEXPR
+      reverse_iterator
+      rend() _GLIBCXX_NOEXCEPT
+      { return reverse_iterator(this->begin()); }
+
+      /**
+       *  Returns a read-only (constant) reverse iterator that points
+       *  to one before the first character in the %string.  Iteration
+       *  is done in reverse element order.
+       */
+      _GLIBCXX20_CONSTEXPR
+      const_reverse_iterator
+      rend() const _GLIBCXX_NOEXCEPT
+      { return const_reverse_iterator(this->begin()); }
+
+#if __cplusplus >= 201103L
+      /**
+       *  Returns a read-only (constant) iterator that points to the first
+       *  character in the %string.
+       */
+      _GLIBCXX20_CONSTEXPR
+      const_iterator
+      cbegin() const noexcept
+      { return const_iterator(this->_M_data()); }
+
+      /**
+       *  Returns a read-only (constant) iterator that points one past the
+       *  last character in the %string.
+       */
+      _GLIBCXX20_CONSTEXPR
+      const_iterator
+      cend() const noexcept
+      { return const_iterator(this->_M_data() + this->size()); }
+
+      /**
+       *  Returns a read-only (constant) reverse iterator that points
+       *  to the last character in the %string.  Iteration is done in
+       *  reverse element order.
+       */
+      _GLIBCXX20_CONSTEXPR
+      const_reverse_iterator
+      crbegin() const noexcept
+      { return const_reverse_iterator(this->end()); }
+
+      /**
+       *  Returns a read-only (constant) reverse iterator that points
+       *  to one before the first character in the %string.  Iteration
+       *  is done in reverse element order.
+       */
+      _GLIBCXX20_CONSTEXPR
+      const_reverse_iterator
+      crend() const noexcept
+      { return const_reverse_iterator(this->begin()); }
+#endif
+
+    public:
+      // Capacity:
+      ///  Returns the number of characters in the string, not including any
+      ///  null-termination.
+      _GLIBCXX20_CONSTEXPR
+      size_type
+      size() const _GLIBCXX_NOEXCEPT
+      { return _M_string_length; }
+
+      ///  Returns the number of characters in the string, not including any
+      ///  null-termination.
+      _GLIBCXX20_CONSTEXPR
+      size_type
+      length() const _GLIBCXX_NOEXCEPT
+      { return _M_string_length; }
+
+      ///  Returns the size() of the largest possible %string.
+      _GLIBCXX20_CONSTEXPR
+      size_type
+      max_size() const _GLIBCXX_NOEXCEPT
+      { return (_Alloc_traits::max_size(_M_get_allocator()) - 1) / 2; }
+
+      /**
+       *  @brief  Resizes the %string to the specified number of characters.
+       *  @param  __n  Number of characters the %string should contain.
+       *  @param  __c  Character to fill any new elements.
+       *
+       *  This function will %resize the %string to the specified
+       *  number of characters.  If the number is smaller than the
+       *  %string's current size the %string is truncated, otherwise
+       *  the %string is extended and new elements are %set to @a __c.
+       */
+      _GLIBCXX20_CONSTEXPR
+      void
+      resize(size_type __n, _CharT __c);
+
+      /**
+       *  @brief  Resizes the %string to the specified number of characters.
+       *  @param  __n  Number of characters the %string should contain.
+       *
+       *  This function will resize the %string to the specified length.  If
+       *  the new size is smaller than the %string's current size the %string
+       *  is truncated, otherwise the %string is extended and new characters
+       *  are default-constructed.  For basic types such as char, this means
+       *  setting them to 0.
+       */
+      _GLIBCXX20_CONSTEXPR
+      void
+      resize(size_type __n)
+      { this->resize(__n, _CharT()); }
+
+#if __cplusplus >= 201103L
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+      ///  A non-binding request to reduce capacity() to size().
+      _GLIBCXX20_CONSTEXPR
+      void
+      shrink_to_fit() noexcept
+      { reserve(); }
+#pragma GCC diagnostic pop
+#endif
+
+#if __cplusplus > 202002L
+#define __cpp_lib_string_resize_and_overwrite 202110L
+      template<typename _Operation>
+	constexpr void
+	resize_and_overwrite(size_type __n, _Operation __op);
+#endif
+
+      /**
+       *  Returns the total number of characters that the %string can hold
+       *  before needing to allocate more memory.
+       */
+      _GLIBCXX20_CONSTEXPR
+      size_type
+      capacity() const _GLIBCXX_NOEXCEPT
+      {
+	return _M_is_local() ? size_type(_S_local_capacity)
+	                     : _M_allocated_capacity;
+      }
+
+      /**
+       *  @brief  Attempt to preallocate enough memory for specified number of
+       *          characters.
+       *  @param  __res_arg  Number of characters required.
+       *  @throw  std::length_error  If @a __res_arg exceeds @c max_size().
+       *
+       *  This function attempts to reserve enough memory for the
+       *  %string to hold the specified number of characters.  If the
+       *  number requested is more than max_size(), length_error is
+       *  thrown.
+       *
+       *  The advantage of this function is that if optimal code is a
+       *  necessity and the user can determine the string length that will be
+       *  required, the user can reserve the memory in %advance, and thus
+       *  prevent a possible reallocation of memory and copying of %string
+       *  data.
+       */
+      _GLIBCXX20_CONSTEXPR
+      void
+      reserve(size_type __res_arg);
+
+      /**
+       *  Equivalent to shrink_to_fit().
+       */
+#if __cplusplus > 201703L
+      [[deprecated("use shrink_to_fit() instead")]]
+#endif
+      _GLIBCXX20_CONSTEXPR
+      void
+      reserve();
+
+      /**
+       *  Erases the string, making it empty.
+       */
+      _GLIBCXX20_CONSTEXPR
+      void
+      clear() _GLIBCXX_NOEXCEPT
+      { _M_set_length(0); }
+
+      /**
+       *  Returns true if the %string is empty.  Equivalent to 
+       *  <code>*this == ""</code>.
+       */
+      _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
+      bool
+      empty() const _GLIBCXX_NOEXCEPT
+      { return this->size() == 0; }
+
+      // Element access:
+      /**
+       *  @brief  Subscript access to the data contained in the %string.
+       *  @param  __pos  The index of the character to access.
+       *  @return  Read-only (constant) reference to the character.
+       *
+       *  This operator allows for easy, array-style, data access.
+       *  Note that data access with this operator is unchecked and
+       *  out_of_range lookups are not defined. (For checked lookups
+       *  see at().)
+       */
+      _GLIBCXX20_CONSTEXPR
+      const_reference
+      operator[] (size_type __pos) const _GLIBCXX_NOEXCEPT
+      {
+	__glibcxx_assert(__pos <= size());
+	return _M_data()[__pos];
+      }
+
+      /**
+       *  @brief  Subscript access to the data contained in the %string.
+       *  @param  __pos  The index of the character to access.
+       *  @return  Read/write reference to the character.
+       *
+       *  This operator allows for easy, array-style, data access.
+       *  Note that data access with this operator is unchecked and
+       *  out_of_range lookups are not defined. (For checked lookups
+       *  see at().)
+       */
+      _GLIBCXX20_CONSTEXPR
+      reference
+      operator[](size_type __pos)
+      {
+        // Allow pos == size() both in C++98 mode, as v3 extension,
+	// and in C++11 mode.
+	__glibcxx_assert(__pos <= size());
+        // In pedantic mode be strict in C++98 mode.
+	_GLIBCXX_DEBUG_PEDASSERT(__cplusplus >= 201103L || __pos < size());
+	return _M_data()[__pos];
+      }
+
+      /**
+       *  @brief  Provides access to the data contained in the %string.
+       *  @param __n The index of the character to access.
+       *  @return  Read-only (const) reference to the character.
+       *  @throw  std::out_of_range  If @a n is an invalid index.
+       *
+       *  This function provides for safer data access.  The parameter is
+       *  first checked that it is in the range of the string.  The function
+       *  throws out_of_range if the check fails.
+       */
+      _GLIBCXX20_CONSTEXPR
+      const_reference
+      at(size_type __n) const
+      {
+	if (__n >= this->size())
+	  __throw_out_of_range_fmt(__N("basic_string::at: __n "
+				       "(which is %zu) >= this->size() "
+				       "(which is %zu)"),
+				   __n, this->size());
+	return _M_data()[__n];
+      }
+
+      /**
+       *  @brief  Provides access to the data contained in the %string.
+       *  @param __n The index of the character to access.
+       *  @return  Read/write reference to the character.
+       *  @throw  std::out_of_range  If @a n is an invalid index.
+       *
+       *  This function provides for safer data access.  The parameter is
+       *  first checked that it is in the range of the string.  The function
+       *  throws out_of_range if the check fails.
+       */
+      _GLIBCXX20_CONSTEXPR
+      reference
+      at(size_type __n)
+      {
+	if (__n >= size())
+	  __throw_out_of_range_fmt(__N("basic_string::at: __n "
+				       "(which is %zu) >= this->size() "
+				       "(which is %zu)"),
+				   __n, this->size());
+	return _M_data()[__n];
+      }
+
+#if __cplusplus >= 201103L
+      /**
+       *  Returns a read/write reference to the data at the first
+       *  element of the %string.
+       */
+      _GLIBCXX20_CONSTEXPR
+      reference
+      front() noexcept
+      {
+	__glibcxx_assert(!empty());
+	return operator[](0);
+      }
+
+      /**
+       *  Returns a read-only (constant) reference to the data at the first
+       *  element of the %string.
+       */
+      _GLIBCXX20_CONSTEXPR
+      const_reference
+      front() const noexcept
+      {
+	__glibcxx_assert(!empty());
+	return operator[](0);
+      }
+
+      /**
+       *  Returns a read/write reference to the data at the last
+       *  element of the %string.
+       */
+      _GLIBCXX20_CONSTEXPR
+      reference
+      back() noexcept
+      {
+	__glibcxx_assert(!empty());
+	return operator[](this->size() - 1);
+      }
+
+      /**
+       *  Returns a read-only (constant) reference to the data at the
+       *  last element of the %string.
+       */
+      _GLIBCXX20_CONSTEXPR
+      const_reference
+      back() const noexcept
+      {
+	__glibcxx_assert(!empty());
+	return operator[](this->size() - 1);
+      }
+#endif
+
+      // Modifiers:
+      /**
+       *  @brief  Append a string to this string.
+       *  @param __str  The string to append.
+       *  @return  Reference to this string.
+       */
+      _GLIBCXX20_CONSTEXPR
+      basic_string&
+      operator+=(const basic_string& __str)
+      { return this->append(__str); }
+
+      /**
+       *  @brief  Append a C string.
+       *  @param __s  The C string to append.
+       *  @return  Reference to this string.
+       */
+      _GLIBCXX20_CONSTEXPR
+      basic_string&
+      operator+=(const _CharT* __s)
+      { return this->append(__s); }
+
+      /**
+       *  @brief  Append a character.
+       *  @param __c  The character to append.
+       *  @return  Reference to this string.
+       */
+      _GLIBCXX20_CONSTEXPR
+      basic_string&
+      operator+=(_CharT __c)
+      {
+	this->push_back(__c);
+	return *this;
+      }
+
+#if __cplusplus >= 201103L
+      /**
+       *  @brief  Append an initializer_list of characters.
+       *  @param __l  The initializer_list of characters to be appended.
+       *  @return  Reference to this string.
+       */
+      _GLIBCXX20_CONSTEXPR
+      basic_string&
+      operator+=(initializer_list<_CharT> __l)
+      { return this->append(__l.begin(), __l.size()); }
+#endif // C++11
+
+#if __cplusplus >= 201703L
+      /**
+       *  @brief  Append a string_view.
+       *  @param __svt  An object convertible to string_view to be appended.
+       *  @return  Reference to this string.
+       */
+      template<typename _Tp>
+	_GLIBCXX20_CONSTEXPR
+	_If_sv<_Tp, basic_string&>
+	operator+=(const _Tp& __svt)
+	{ return this->append(__svt); }
+#endif // C++17
+
+      /**
+       *  @brief  Append a string to this string.
+       *  @param __str  The string to append.
+       *  @return  Reference to this string.
+       */
+      _GLIBCXX20_CONSTEXPR
+      basic_string&
+      append(const basic_string& __str)
+      { return this->append(__str._M_data(), __str.size()); }
+
+      /**
+       *  @brief  Append a substring.
+       *  @param __str  The string to append.
+       *  @param __pos  Index of the first character of str to append.
+       *  @param __n  The number of characters to append.
+       *  @return  Reference to this string.
+       *  @throw  std::out_of_range if @a __pos is not a valid index.
+       *
+       *  This function appends @a __n characters from @a __str
+       *  starting at @a __pos to this string.  If @a __n is is larger
+       *  than the number of available characters in @a __str, the
+       *  remainder of @a __str is appended.
+       */
+      _GLIBCXX20_CONSTEXPR
+      basic_string&
+      append(const basic_string& __str, size_type __pos, size_type __n = npos)
+      { return this->append(__str._M_data()
+			    + __str._M_check(__pos, "basic_string::append"),
+			    __str._M_limit(__pos, __n)); }
+
+      /**
+       *  @brief  Append a C substring.
+       *  @param __s  The C string to append.
+       *  @param __n  The number of characters to append.
+       *  @return  Reference to this string.
+       */
+      _GLIBCXX20_CONSTEXPR
+      basic_string&
+      append(const _CharT* __s, size_type __n)
+      {
+	__glibcxx_requires_string_len(__s, __n);
+	_M_check_length(size_type(0), __n, "basic_string::append");
+	return _M_append(__s, __n);
+      }
+
+      /**
+       *  @brief  Append a C string.
+       *  @param __s  The C string to append.
+       *  @return  Reference to this string.
+       */
+      _GLIBCXX20_CONSTEXPR
+      basic_string&
+      append(const _CharT* __s)
+      {
+	__glibcxx_requires_string(__s);
+	const size_type __n = traits_type::length(__s);
+	_M_check_length(size_type(0), __n, "basic_string::append");
+	return _M_append(__s, __n);
+      }
+
+      /**
+       *  @brief  Append multiple characters.
+       *  @param __n  The number of characters to append.
+       *  @param __c  The character to use.
+       *  @return  Reference to this string.
+       *
+       *  Appends __n copies of __c to this string.
+       */
+      _GLIBCXX20_CONSTEXPR
+      basic_string&
+      append(size_type __n, _CharT __c)
+      { return _M_replace_aux(this->size(), size_type(0), __n, __c); }
+
+#if __cplusplus >= 201103L
+      /**
+       *  @brief  Append an initializer_list of characters.
+       *  @param __l  The initializer_list of characters to append.
+       *  @return  Reference to this string.
+       */
+      _GLIBCXX20_CONSTEXPR
+      basic_string&
+      append(initializer_list<_CharT> __l)
+      { return this->append(__l.begin(), __l.size()); }
+#endif // C++11
+
+      /**
+       *  @brief  Append a range of characters.
+       *  @param __first  Iterator referencing the first character to append.
+       *  @param __last  Iterator marking the end of the range.
+       *  @return  Reference to this string.
+       *
+       *  Appends characters in the range [__first,__last) to this string.
+       */
+#if __cplusplus >= 201103L
+      template<class _InputIterator,
+	       typename = std::_RequireInputIter<_InputIterator>>
+	_GLIBCXX20_CONSTEXPR
+#else
+      template<class _InputIterator>
+#endif
+        basic_string&
+        append(_InputIterator __first, _InputIterator __last)
+        { return this->replace(end(), end(), __first, __last); }
+
+#if __cplusplus >= 201703L
+      /**
+       *  @brief  Append a string_view.
+       *  @param __svt  An object convertible to string_view to be appended.
+       *  @return  Reference to this string.
+       */
+      template<typename _Tp>
+	_GLIBCXX20_CONSTEXPR
+        _If_sv<_Tp, basic_string&>
+        append(const _Tp& __svt)
+        {
+          __sv_type __sv = __svt;
+          return this->append(__sv.data(), __sv.size());
+        }
+
+      /**
+       *  @brief  Append a range of characters from a string_view.
+       *  @param __svt  An object convertible to string_view to be appended from.
+       *  @param __pos The position in the string_view to append from.
+       *  @param __n   The number of characters to append from the string_view.
+       *  @return  Reference to this string.
+       */
+      template<typename _Tp>
+	_GLIBCXX20_CONSTEXPR
+        _If_sv<_Tp, basic_string&>
+	append(const _Tp& __svt, size_type __pos, size_type __n = npos)
+	{
+	  __sv_type __sv = __svt;
+	  return _M_append(__sv.data()
+	      + std::__sv_check(__sv.size(), __pos, "basic_string::append"),
+	      std::__sv_limit(__sv.size(), __pos, __n));
+	}
+#endif // C++17
+
+      /**
+       *  @brief  Append a single character.
+       *  @param __c  Character to append.
+       */
+      _GLIBCXX20_CONSTEXPR
+      void
+      push_back(_CharT __c)
+      {
+	const size_type __size = this->size();
+	if (__size + 1 > this->capacity())
+	  this->_M_mutate(__size, size_type(0), 0, size_type(1));
+	traits_type::assign(this->_M_data()[__size], __c);
+	this->_M_set_length(__size + 1);
+      }
+
+      /**
+       *  @brief  Set value to contents of another string.
+       *  @param  __str  Source string to use.
+       *  @return  Reference to this string.
+       */
+      _GLIBCXX20_CONSTEXPR
+      basic_string&
+      assign(const basic_string& __str)
+      {
+#if __cplusplus >= 201103L
+	if (_Alloc_traits::_S_propagate_on_copy_assign())
+	  {
+	    if (!_Alloc_traits::_S_always_equal() && !_M_is_local()
+		&& _M_get_allocator() != __str._M_get_allocator())
+	      {
+		// Propagating allocator cannot free existing storage so must
+		// deallocate it before replacing current allocator.
+		if (__str.size() <= _S_local_capacity)
+		  {
+		    _M_destroy(_M_allocated_capacity);
+		    _M_data(_M_use_local_data());
+		    _M_set_length(0);
+		  }
+		else
+		  {
+		    const auto __len = __str.size();
+		    auto __alloc = __str._M_get_allocator();
+		    // If this allocation throws there are no effects:
+		    auto __ptr = _Alloc_traits::allocate(__alloc, __len + 1);
+		    _M_destroy(_M_allocated_capacity);
+		    _M_data(__ptr);
+		    _M_capacity(__len);
+		    _M_set_length(__len);
+		  }
+	      }
+	    std::__alloc_on_copy(_M_get_allocator(), __str._M_get_allocator());
+	  }
+#endif
+	this->_M_assign(__str);
+	return *this;
+      }
+
+#if __cplusplus >= 201103L
+      /**
+       *  @brief  Set value to contents of another string.
+       *  @param  __str  Source string to use.
+       *  @return  Reference to this string.
+       *
+       *  This function sets this string to the exact contents of @a __str.
+       *  @a __str is a valid, but unspecified string.
+       */
+      _GLIBCXX20_CONSTEXPR
+      basic_string&
+      assign(basic_string&& __str)
+      noexcept(_Alloc_traits::_S_nothrow_move())
+      {
+	// _GLIBCXX_RESOLVE_LIB_DEFECTS
+	// 2063. Contradictory requirements for string move assignment
+	return *this = std::move(__str);
+      }
+#endif // C++11
+
+      /**
+       *  @brief  Set value to a substring of a string.
+       *  @param __str  The string to use.
+       *  @param __pos  Index of the first character of str.
+       *  @param __n  Number of characters to use.
+       *  @return  Reference to this string.
+       *  @throw  std::out_of_range if @a pos is not a valid index.
+       *
+       *  This function sets this string to the substring of @a __str
+       *  consisting of @a __n characters at @a __pos.  If @a __n is
+       *  is larger than the number of available characters in @a
+       *  __str, the remainder of @a __str is used.
+       */
+      _GLIBCXX20_CONSTEXPR
+      basic_string&
+      assign(const basic_string& __str, size_type __pos, size_type __n = npos)
+      { return _M_replace(size_type(0), this->size(), __str._M_data()
+			  + __str._M_check(__pos, "basic_string::assign"),
+			  __str._M_limit(__pos, __n)); }
+
+      /**
+       *  @brief  Set value to a C substring.
+       *  @param __s  The C string to use.
+       *  @param __n  Number of characters to use.
+       *  @return  Reference to this string.
+       *
+       *  This function sets the value of this string to the first @a __n
+       *  characters of @a __s.  If @a __n is is larger than the number of
+       *  available characters in @a __s, the remainder of @a __s is used.
+       */
+      _GLIBCXX20_CONSTEXPR
+      basic_string&
+      assign(const _CharT* __s, size_type __n)
+      {
+	__glibcxx_requires_string_len(__s, __n);
+	return _M_replace(size_type(0), this->size(), __s, __n);
+      }
+
+      /**
+       *  @brief  Set value to contents of a C string.
+       *  @param __s  The C string to use.
+       *  @return  Reference to this string.
+       *
+       *  This function sets the value of this string to the value of @a __s.
+       *  The data is copied, so there is no dependence on @a __s once the
+       *  function returns.
+       */
+      _GLIBCXX20_CONSTEXPR
+      basic_string&
+      assign(const _CharT* __s)
+      {
+	__glibcxx_requires_string(__s);
+	return _M_replace(size_type(0), this->size(), __s,
+			  traits_type::length(__s));
+      }
+
+      /**
+       *  @brief  Set value to multiple characters.
+       *  @param __n  Length of the resulting string.
+       *  @param __c  The character to use.
+       *  @return  Reference to this string.
+       *
+       *  This function sets the value of this string to @a __n copies of
+       *  character @a __c.
+       */
+      _GLIBCXX20_CONSTEXPR
+      basic_string&
+      assign(size_type __n, _CharT __c)
+      { return _M_replace_aux(size_type(0), this->size(), __n, __c); }
+
+      /**
+       *  @brief  Set value to a range of characters.
+       *  @param __first  Iterator referencing the first character to append.
+       *  @param __last  Iterator marking the end of the range.
+       *  @return  Reference to this string.
+       *
+       *  Sets value of string to characters in the range [__first,__last).
+      */
+#if __cplusplus >= 201103L
+      template<class _InputIterator,
+	       typename = std::_RequireInputIter<_InputIterator>>
+	_GLIBCXX20_CONSTEXPR
+#else
+      template<class _InputIterator>
+#endif
+        basic_string&
+        assign(_InputIterator __first, _InputIterator __last)
+        { return this->replace(begin(), end(), __first, __last); }
+
+#if __cplusplus >= 201103L
+      /**
+       *  @brief  Set value to an initializer_list of characters.
+       *  @param __l  The initializer_list of characters to assign.
+       *  @return  Reference to this string.
+       */
+      _GLIBCXX20_CONSTEXPR
+      basic_string&
+      assign(initializer_list<_CharT> __l)
+      { return this->assign(__l.begin(), __l.size()); }
+#endif // C++11
+
+#if __cplusplus >= 201703L
+      /**
+       *  @brief  Set value from a string_view.
+       *  @param __svt  The source object convertible to string_view.
+       *  @return  Reference to this string.
+       */
+      template<typename _Tp>
+	_GLIBCXX20_CONSTEXPR
+	_If_sv<_Tp, basic_string&>
+	assign(const _Tp& __svt)
+	{
+	  __sv_type __sv = __svt;
+	  return this->assign(__sv.data(), __sv.size());
+	}
+
+      /**
+       *  @brief  Set value from a range of characters in a string_view.
+       *  @param __svt  The source object convertible to string_view.
+       *  @param __pos  The position in the string_view to assign from.
+       *  @param __n  The number of characters to assign.
+       *  @return  Reference to this string.
+       */
+      template<typename _Tp>
+	_GLIBCXX20_CONSTEXPR
+	_If_sv<_Tp, basic_string&>
+	assign(const _Tp& __svt, size_type __pos, size_type __n = npos)
+	{
+	  __sv_type __sv = __svt;
+	  return _M_replace(size_type(0), this->size(),
+	      __sv.data()
+	      + std::__sv_check(__sv.size(), __pos, "basic_string::assign"),
+	      std::__sv_limit(__sv.size(), __pos, __n));
+	}
+#endif // C++17
+
+#if __cplusplus >= 201103L
+      /**
+       *  @brief  Insert multiple characters.
+       *  @param __p  Const_iterator referencing location in string to
+       *              insert at.
+       *  @param __n  Number of characters to insert
+       *  @param __c  The character to insert.
+       *  @return  Iterator referencing the first inserted char.
+       *  @throw  std::length_error  If new length exceeds @c max_size().
+       *
+       *  Inserts @a __n copies of character @a __c starting at the
+       *  position referenced by iterator @a __p.  If adding
+       *  characters causes the length to exceed max_size(),
+       *  length_error is thrown.  The value of the string doesn't
+       *  change if an error is thrown.
+      */
+      _GLIBCXX20_CONSTEXPR
+      iterator
+      insert(const_iterator __p, size_type __n, _CharT __c)
+      {
+	_GLIBCXX_DEBUG_PEDASSERT(__p >= begin() && __p <= end());
+	const size_type __pos = __p - begin();
+	this->replace(__p, __p, __n, __c);
+	return iterator(this->_M_data() + __pos);
+      }
+#else
+      /**
+       *  @brief  Insert multiple characters.
+       *  @param __p  Iterator referencing location in string to insert at.
+       *  @param __n  Number of characters to insert
+       *  @param __c  The character to insert.
+       *  @throw  std::length_error  If new length exceeds @c max_size().
+       *
+       *  Inserts @a __n copies of character @a __c starting at the
+       *  position referenced by iterator @a __p.  If adding
+       *  characters causes the length to exceed max_size(),
+       *  length_error is thrown.  The value of the string doesn't
+       *  change if an error is thrown.
+      */
+      void
+      insert(iterator __p, size_type __n, _CharT __c)
+      {	this->replace(__p, __p, __n, __c);  }
+#endif
+
+#if __cplusplus >= 201103L
+      /**
+       *  @brief  Insert a range of characters.
+       *  @param __p  Const_iterator referencing location in string to
+       *              insert at.
+       *  @param __beg  Start of range.
+       *  @param __end  End of range.
+       *  @return  Iterator referencing the first inserted char.
+       *  @throw  std::length_error  If new length exceeds @c max_size().
+       *
+       *  Inserts characters in range [beg,end).  If adding characters
+       *  causes the length to exceed max_size(), length_error is
+       *  thrown.  The value of the string doesn't change if an error
+       *  is thrown.
+      */
+      template<class _InputIterator,
+	       typename = std::_RequireInputIter<_InputIterator>>
+	_GLIBCXX20_CONSTEXPR
+	iterator
+        insert(const_iterator __p, _InputIterator __beg, _InputIterator __end)
+        {
+	  _GLIBCXX_DEBUG_PEDASSERT(__p >= begin() && __p <= end());
+	  const size_type __pos = __p - begin();
+	  this->replace(__p, __p, __beg, __end);
+	  return iterator(this->_M_data() + __pos);
+	}
+#else
+      /**
+       *  @brief  Insert a range of characters.
+       *  @param __p  Iterator referencing location in string to insert at.
+       *  @param __beg  Start of range.
+       *  @param __end  End of range.
+       *  @throw  std::length_error  If new length exceeds @c max_size().
+       *
+       *  Inserts characters in range [__beg,__end).  If adding
+       *  characters causes the length to exceed max_size(),
+       *  length_error is thrown.  The value of the string doesn't
+       *  change if an error is thrown.
+      */
+      template<class _InputIterator>
+        void
+        insert(iterator __p, _InputIterator __beg, _InputIterator __end)
+        { this->replace(__p, __p, __beg, __end); }
+#endif
+
+#if __cplusplus >= 201103L
+      /**
+       *  @brief  Insert an initializer_list of characters.
+       *  @param __p  Iterator referencing location in string to insert at.
+       *  @param __l  The initializer_list of characters to insert.
+       *  @throw  std::length_error  If new length exceeds @c max_size().
+       */
+      _GLIBCXX20_CONSTEXPR
+      iterator
+      insert(const_iterator __p, initializer_list<_CharT> __l)
+      { return this->insert(__p, __l.begin(), __l.end()); }
+
+#ifdef _GLIBCXX_DEFINING_STRING_INSTANTIATIONS
+      // See PR libstdc++/83328
+      void
+      insert(iterator __p, initializer_list<_CharT> __l)
+      {
+	_GLIBCXX_DEBUG_PEDASSERT(__p >= begin() && __p <= end());
+	this->insert(__p - begin(), __l.begin(), __l.size());
+      }
+#endif
+#endif // C++11
+
+      /**
+       *  @brief  Insert value of a string.
+       *  @param __pos1 Position in string to insert at.
+       *  @param __str  The string to insert.
+       *  @return  Reference to this string.
+       *  @throw  std::length_error  If new length exceeds @c max_size().
+       *
+       *  Inserts value of @a __str starting at @a __pos1.  If adding
+       *  characters causes the length to exceed max_size(),
+       *  length_error is thrown.  The value of the string doesn't
+       *  change if an error is thrown.
+      */
+      _GLIBCXX20_CONSTEXPR
+      basic_string&
+      insert(size_type __pos1, const basic_string& __str)
+      { return this->replace(__pos1, size_type(0),
+			     __str._M_data(), __str.size()); }
+
+      /**
+       *  @brief  Insert a substring.
+       *  @param __pos1  Position in string to insert at.
+       *  @param __str   The string to insert.
+       *  @param __pos2  Start of characters in str to insert.
+       *  @param __n  Number of characters to insert.
+       *  @return  Reference to this string.
+       *  @throw  std::length_error  If new length exceeds @c max_size().
+       *  @throw  std::out_of_range  If @a pos1 > size() or
+       *  @a __pos2 > @a str.size().
+       *
+       *  Starting at @a pos1, insert @a __n character of @a __str
+       *  beginning with @a __pos2.  If adding characters causes the
+       *  length to exceed max_size(), length_error is thrown.  If @a
+       *  __pos1 is beyond the end of this string or @a __pos2 is
+       *  beyond the end of @a __str, out_of_range is thrown.  The
+       *  value of the string doesn't change if an error is thrown.
+      */
+      _GLIBCXX20_CONSTEXPR
+      basic_string&
+      insert(size_type __pos1, const basic_string& __str,
+	     size_type __pos2, size_type __n = npos)
+      { return this->replace(__pos1, size_type(0), __str._M_data()
+			     + __str._M_check(__pos2, "basic_string::insert"),
+			     __str._M_limit(__pos2, __n)); }
+
+      /**
+       *  @brief  Insert a C substring.
+       *  @param __pos  Position in string to insert at.
+       *  @param __s  The C string to insert.
+       *  @param __n  The number of characters to insert.
+       *  @return  Reference to this string.
+       *  @throw  std::length_error  If new length exceeds @c max_size().
+       *  @throw  std::out_of_range  If @a __pos is beyond the end of this
+       *  string.
+       *
+       *  Inserts the first @a __n characters of @a __s starting at @a
+       *  __pos.  If adding characters causes the length to exceed
+       *  max_size(), length_error is thrown.  If @a __pos is beyond
+       *  end(), out_of_range is thrown.  The value of the string
+       *  doesn't change if an error is thrown.
+      */
+      _GLIBCXX20_CONSTEXPR
+      basic_string&
+      insert(size_type __pos, const _CharT* __s, size_type __n)
+      { return this->replace(__pos, size_type(0), __s, __n); }
+
+      /**
+       *  @brief  Insert a C string.
+       *  @param __pos  Position in string to insert at.
+       *  @param __s  The C string to insert.
+       *  @return  Reference to this string.
+       *  @throw  std::length_error  If new length exceeds @c max_size().
+       *  @throw  std::out_of_range  If @a pos is beyond the end of this
+       *  string.
+       *
+       *  Inserts the first @a n characters of @a __s starting at @a __pos.  If
+       *  adding characters causes the length to exceed max_size(),
+       *  length_error is thrown.  If @a __pos is beyond end(), out_of_range is
+       *  thrown.  The value of the string doesn't change if an error is
+       *  thrown.
+      */
+      _GLIBCXX20_CONSTEXPR
+      basic_string&
+      insert(size_type __pos, const _CharT* __s)
+      {
+	__glibcxx_requires_string(__s);
+	return this->replace(__pos, size_type(0), __s,
+			     traits_type::length(__s));
+      }
+
+      /**
+       *  @brief  Insert multiple characters.
+       *  @param __pos  Index in string to insert at.
+       *  @param __n  Number of characters to insert
+       *  @param __c  The character to insert.
+       *  @return  Reference to this string.
+       *  @throw  std::length_error  If new length exceeds @c max_size().
+       *  @throw  std::out_of_range  If @a __pos is beyond the end of this
+       *  string.
+       *
+       *  Inserts @a __n copies of character @a __c starting at index
+       *  @a __pos.  If adding characters causes the length to exceed
+       *  max_size(), length_error is thrown.  If @a __pos > length(),
+       *  out_of_range is thrown.  The value of the string doesn't
+       *  change if an error is thrown.
+      */
+      _GLIBCXX20_CONSTEXPR
+      basic_string&
+      insert(size_type __pos, size_type __n, _CharT __c)
+      { return _M_replace_aux(_M_check(__pos, "basic_string::insert"),
+			      size_type(0), __n, __c); }
+
+      /**
+       *  @brief  Insert one character.
+       *  @param __p  Iterator referencing position in string to insert at.
+       *  @param __c  The character to insert.
+       *  @return  Iterator referencing newly inserted char.
+       *  @throw  std::length_error  If new length exceeds @c max_size().
+       *
+       *  Inserts character @a __c at position referenced by @a __p.
+       *  If adding character causes the length to exceed max_size(),
+       *  length_error is thrown.  If @a __p is beyond end of string,
+       *  out_of_range is thrown.  The value of the string doesn't
+       *  change if an error is thrown.
+      */
+      _GLIBCXX20_CONSTEXPR
+      iterator
+      insert(__const_iterator __p, _CharT __c)
+      {
+	_GLIBCXX_DEBUG_PEDASSERT(__p >= begin() && __p <= end());
+	const size_type __pos = __p - begin();
+	_M_replace_aux(__pos, size_type(0), size_type(1), __c);
+	return iterator(_M_data() + __pos);
+      }
+
+#if __cplusplus >= 201703L
+      /**
+       *  @brief  Insert a string_view.
+       *  @param __pos  Position in string to insert at.
+       *  @param __svt  The object convertible to string_view to insert.
+       *  @return  Reference to this string.
+      */
+      template<typename _Tp>
+	_GLIBCXX20_CONSTEXPR
+	_If_sv<_Tp, basic_string&>
+	insert(size_type __pos, const _Tp& __svt)
+	{
+	  __sv_type __sv = __svt;
+	  return this->insert(__pos, __sv.data(), __sv.size());
+	}
+
+      /**
+       *  @brief  Insert a string_view.
+       *  @param __pos1  Position in string to insert at.
+       *  @param __svt   The object convertible to string_view to insert from.
+       *  @param __pos2  Start of characters in str to insert.
+       *  @param __n    The number of characters to insert.
+       *  @return  Reference to this string.
+      */
+      template<typename _Tp>
+	_GLIBCXX20_CONSTEXPR
+	_If_sv<_Tp, basic_string&>
+	insert(size_type __pos1, const _Tp& __svt,
+	       size_type __pos2, size_type __n = npos)
+	{
+	  __sv_type __sv = __svt;
+	  return this->replace(__pos1, size_type(0),
+	      __sv.data()
+	      + std::__sv_check(__sv.size(), __pos2, "basic_string::insert"),
+	      std::__sv_limit(__sv.size(), __pos2, __n));
+	}
+#endif // C++17
+
+      /**
+       *  @brief  Remove characters.
+       *  @param __pos  Index of first character to remove (default 0).
+       *  @param __n  Number of characters to remove (default remainder).
+       *  @return  Reference to this string.
+       *  @throw  std::out_of_range  If @a pos is beyond the end of this
+       *  string.
+       *
+       *  Removes @a __n characters from this string starting at @a
+       *  __pos.  The length of the string is reduced by @a __n.  If
+       *  there are < @a __n characters to remove, the remainder of
+       *  the string is truncated.  If @a __p is beyond end of string,
+       *  out_of_range is thrown.  The value of the string doesn't
+       *  change if an error is thrown.
+      */
+      _GLIBCXX20_CONSTEXPR
+      basic_string&
+      erase(size_type __pos = 0, size_type __n = npos)
+      {
+	_M_check(__pos, "basic_string::erase");
+	if (__n == npos)
+	  this->_M_set_length(__pos);
+	else if (__n != 0)
+	  this->_M_erase(__pos, _M_limit(__pos, __n));
+	return *this;
+      }
+
+      /**
+       *  @brief  Remove one character.
+       *  @param __position  Iterator referencing the character to remove.
+       *  @return  iterator referencing same location after removal.
+       *
+       *  Removes the character at @a __position from this string. The value
+       *  of the string doesn't change if an error is thrown.
+      */
+      _GLIBCXX20_CONSTEXPR
+      iterator
+      erase(__const_iterator __position)
+      {
+	_GLIBCXX_DEBUG_PEDASSERT(__position >= begin()
+				 && __position < end());
+	const size_type __pos = __position - begin();
+	this->_M_erase(__pos, size_type(1));
+	return iterator(_M_data() + __pos);
+      }
+
+      /**
+       *  @brief  Remove a range of characters.
+       *  @param __first  Iterator referencing the first character to remove.
+       *  @param __last  Iterator referencing the end of the range.
+       *  @return  Iterator referencing location of first after removal.
+       *
+       *  Removes the characters in the range [first,last) from this string.
+       *  The value of the string doesn't change if an error is thrown.
+      */
+      _GLIBCXX20_CONSTEXPR
+      iterator
+      erase(__const_iterator __first, __const_iterator __last)
+      {
+	_GLIBCXX_DEBUG_PEDASSERT(__first >= begin() && __first <= __last
+				 && __last <= end());
+        const size_type __pos = __first - begin();
+	if (__last == end())
+	  this->_M_set_length(__pos);
+	else
+	  this->_M_erase(__pos, __last - __first);
+	return iterator(this->_M_data() + __pos);
+      }
+
+#if __cplusplus >= 201103L
+      /**
+       *  @brief  Remove the last character.
+       *
+       *  The string must be non-empty.
+       */
+      _GLIBCXX20_CONSTEXPR
+      void
+      pop_back() noexcept
+      {
+	__glibcxx_assert(!empty());
+	_M_erase(size() - 1, 1);
+      }
+#endif // C++11
+
+      /**
+       *  @brief  Replace characters with value from another string.
+       *  @param __pos  Index of first character to replace.
+       *  @param __n  Number of characters to be replaced.
+       *  @param __str  String to insert.
+       *  @return  Reference to this string.
+       *  @throw  std::out_of_range  If @a pos is beyond the end of this
+       *  string.
+       *  @throw  std::length_error  If new length exceeds @c max_size().
+       *
+       *  Removes the characters in the range [__pos,__pos+__n) from
+       *  this string.  In place, the value of @a __str is inserted.
+       *  If @a __pos is beyond end of string, out_of_range is thrown.
+       *  If the length of the result exceeds max_size(), length_error
+       *  is thrown.  The value of the string doesn't change if an
+       *  error is thrown.
+      */
+      _GLIBCXX20_CONSTEXPR
+      basic_string&
+      replace(size_type __pos, size_type __n, const basic_string& __str)
+      { return this->replace(__pos, __n, __str._M_data(), __str.size()); }
+
+      /**
+       *  @brief  Replace characters with value from another string.
+       *  @param __pos1  Index of first character to replace.
+       *  @param __n1  Number of characters to be replaced.
+       *  @param __str  String to insert.
+       *  @param __pos2  Index of first character of str to use.
+       *  @param __n2  Number of characters from str to use.
+       *  @return  Reference to this string.
+       *  @throw  std::out_of_range  If @a __pos1 > size() or @a __pos2 >
+       *  __str.size().
+       *  @throw  std::length_error  If new length exceeds @c max_size().
+       *
+       *  Removes the characters in the range [__pos1,__pos1 + n) from this
+       *  string.  In place, the value of @a __str is inserted.  If @a __pos is
+       *  beyond end of string, out_of_range is thrown.  If the length of the
+       *  result exceeds max_size(), length_error is thrown.  The value of the
+       *  string doesn't change if an error is thrown.
+      */
+      _GLIBCXX20_CONSTEXPR
+      basic_string&
+      replace(size_type __pos1, size_type __n1, const basic_string& __str,
+	      size_type __pos2, size_type __n2 = npos)
+      { return this->replace(__pos1, __n1, __str._M_data()
+			     + __str._M_check(__pos2, "basic_string::replace"),
+			     __str._M_limit(__pos2, __n2)); }
+
+      /**
+       *  @brief  Replace characters with value of a C substring.
+       *  @param __pos  Index of first character to replace.
+       *  @param __n1  Number of characters to be replaced.
+       *  @param __s  C string to insert.
+       *  @param __n2  Number of characters from @a s to use.
+       *  @return  Reference to this string.
+       *  @throw  std::out_of_range  If @a pos1 > size().
+       *  @throw  std::length_error  If new length exceeds @c max_size().
+       *
+       *  Removes the characters in the range [__pos,__pos + __n1)
+       *  from this string.  In place, the first @a __n2 characters of
+       *  @a __s are inserted, or all of @a __s if @a __n2 is too large.  If
+       *  @a __pos is beyond end of string, out_of_range is thrown.  If
+       *  the length of result exceeds max_size(), length_error is
+       *  thrown.  The value of the string doesn't change if an error
+       *  is thrown.
+      */
+      _GLIBCXX20_CONSTEXPR
+      basic_string&
+      replace(size_type __pos, size_type __n1, const _CharT* __s,
+	      size_type __n2)
+      {
+	__glibcxx_requires_string_len(__s, __n2);
+	return _M_replace(_M_check(__pos, "basic_string::replace"),
+			  _M_limit(__pos, __n1), __s, __n2);
+      }
+
+      /**
+       *  @brief  Replace characters with value of a C string.
+       *  @param __pos  Index of first character to replace.
+       *  @param __n1  Number of characters to be replaced.
+       *  @param __s  C string to insert.
+       *  @return  Reference to this string.
+       *  @throw  std::out_of_range  If @a pos > size().
+       *  @throw  std::length_error  If new length exceeds @c max_size().
+       *
+       *  Removes the characters in the range [__pos,__pos + __n1)
+       *  from this string.  In place, the characters of @a __s are
+       *  inserted.  If @a __pos is beyond end of string, out_of_range
+       *  is thrown.  If the length of result exceeds max_size(),
+       *  length_error is thrown.  The value of the string doesn't
+       *  change if an error is thrown.
+      */
+      _GLIBCXX20_CONSTEXPR
+      basic_string&
+      replace(size_type __pos, size_type __n1, const _CharT* __s)
+      {
+	__glibcxx_requires_string(__s);
+	return this->replace(__pos, __n1, __s, traits_type::length(__s));
+      }
+
+      /**
+       *  @brief  Replace characters with multiple characters.
+       *  @param __pos  Index of first character to replace.
+       *  @param __n1  Number of characters to be replaced.
+       *  @param __n2  Number of characters to insert.
+       *  @param __c  Character to insert.
+       *  @return  Reference to this string.
+       *  @throw  std::out_of_range  If @a __pos > size().
+       *  @throw  std::length_error  If new length exceeds @c max_size().
+       *
+       *  Removes the characters in the range [pos,pos + n1) from this
+       *  string.  In place, @a __n2 copies of @a __c are inserted.
+       *  If @a __pos is beyond end of string, out_of_range is thrown.
+       *  If the length of result exceeds max_size(), length_error is
+       *  thrown.  The value of the string doesn't change if an error
+       *  is thrown.
+      */
+      _GLIBCXX20_CONSTEXPR
+      basic_string&
+      replace(size_type __pos, size_type __n1, size_type __n2, _CharT __c)
+      { return _M_replace_aux(_M_check(__pos, "basic_string::replace"),
+			      _M_limit(__pos, __n1), __n2, __c); }
+
+      /**
+       *  @brief  Replace range of characters with string.
+       *  @param __i1  Iterator referencing start of range to replace.
+       *  @param __i2  Iterator referencing end of range to replace.
+       *  @param __str  String value to insert.
+       *  @return  Reference to this string.
+       *  @throw  std::length_error  If new length exceeds @c max_size().
+       *
+       *  Removes the characters in the range [__i1,__i2).  In place,
+       *  the value of @a __str is inserted.  If the length of result
+       *  exceeds max_size(), length_error is thrown.  The value of
+       *  the string doesn't change if an error is thrown.
+      */
+      _GLIBCXX20_CONSTEXPR
+      basic_string&
+      replace(__const_iterator __i1, __const_iterator __i2,
+	      const basic_string& __str)
+      { return this->replace(__i1, __i2, __str._M_data(), __str.size()); }
+
+      /**
+       *  @brief  Replace range of characters with C substring.
+       *  @param __i1  Iterator referencing start of range to replace.
+       *  @param __i2  Iterator referencing end of range to replace.
+       *  @param __s  C string value to insert.
+       *  @param __n  Number of characters from s to insert.
+       *  @return  Reference to this string.
+       *  @throw  std::length_error  If new length exceeds @c max_size().
+       *
+       *  Removes the characters in the range [__i1,__i2).  In place,
+       *  the first @a __n characters of @a __s are inserted.  If the
+       *  length of result exceeds max_size(), length_error is thrown.
+       *  The value of the string doesn't change if an error is
+       *  thrown.
+      */
+      _GLIBCXX20_CONSTEXPR
+      basic_string&
+      replace(__const_iterator __i1, __const_iterator __i2,
+	      const _CharT* __s, size_type __n)
+      {
+	_GLIBCXX_DEBUG_PEDASSERT(begin() <= __i1 && __i1 <= __i2
+				 && __i2 <= end());
+	return this->replace(__i1 - begin(), __i2 - __i1, __s, __n);
+      }
+
+      /**
+       *  @brief  Replace range of characters with C string.
+       *  @param __i1  Iterator referencing start of range to replace.
+       *  @param __i2  Iterator referencing end of range to replace.
+       *  @param __s  C string value to insert.
+       *  @return  Reference to this string.
+       *  @throw  std::length_error  If new length exceeds @c max_size().
+       *
+       *  Removes the characters in the range [__i1,__i2).  In place,
+       *  the characters of @a __s are inserted.  If the length of
+       *  result exceeds max_size(), length_error is thrown.  The
+       *  value of the string doesn't change if an error is thrown.
+      */
+      _GLIBCXX20_CONSTEXPR
+      basic_string&
+      replace(__const_iterator __i1, __const_iterator __i2, const _CharT* __s)
+      {
+	__glibcxx_requires_string(__s);
+	return this->replace(__i1, __i2, __s, traits_type::length(__s));
+      }
+
+      /**
+       *  @brief  Replace range of characters with multiple characters
+       *  @param __i1  Iterator referencing start of range to replace.
+       *  @param __i2  Iterator referencing end of range to replace.
+       *  @param __n  Number of characters to insert.
+       *  @param __c  Character to insert.
+       *  @return  Reference to this string.
+       *  @throw  std::length_error  If new length exceeds @c max_size().
+       *
+       *  Removes the characters in the range [__i1,__i2).  In place,
+       *  @a __n copies of @a __c are inserted.  If the length of
+       *  result exceeds max_size(), length_error is thrown.  The
+       *  value of the string doesn't change if an error is thrown.
+      */
+      _GLIBCXX20_CONSTEXPR
+      basic_string&
+      replace(__const_iterator __i1, __const_iterator __i2, size_type __n,
+	      _CharT __c)
+      {
+	_GLIBCXX_DEBUG_PEDASSERT(begin() <= __i1 && __i1 <= __i2
+				 && __i2 <= end());
+	return _M_replace_aux(__i1 - begin(), __i2 - __i1, __n, __c);
+      }
+
+      /**
+       *  @brief  Replace range of characters with range.
+       *  @param __i1  Iterator referencing start of range to replace.
+       *  @param __i2  Iterator referencing end of range to replace.
+       *  @param __k1  Iterator referencing start of range to insert.
+       *  @param __k2  Iterator referencing end of range to insert.
+       *  @return  Reference to this string.
+       *  @throw  std::length_error  If new length exceeds @c max_size().
+       *
+       *  Removes the characters in the range [__i1,__i2).  In place,
+       *  characters in the range [__k1,__k2) are inserted.  If the
+       *  length of result exceeds max_size(), length_error is thrown.
+       *  The value of the string doesn't change if an error is
+       *  thrown.
+      */
+#if __cplusplus >= 201103L
+      template<class _InputIterator,
+	       typename = std::_RequireInputIter<_InputIterator>>
+	_GLIBCXX20_CONSTEXPR
+        basic_string&
+        replace(const_iterator __i1, const_iterator __i2,
+		_InputIterator __k1, _InputIterator __k2)
+        {
+	  _GLIBCXX_DEBUG_PEDASSERT(begin() <= __i1 && __i1 <= __i2
+				   && __i2 <= end());
+	  __glibcxx_requires_valid_range(__k1, __k2);
+	  return this->_M_replace_dispatch(__i1, __i2, __k1, __k2,
+					   std::__false_type());
+	}
+#else
+      template<class _InputIterator>
+#ifdef _GLIBCXX_DISAMBIGUATE_REPLACE_INST
+        typename __enable_if_not_native_iterator<_InputIterator>::__type
+#else
+        basic_string&
+#endif
+        replace(iterator __i1, iterator __i2,
+		_InputIterator __k1, _InputIterator __k2)
+        {
+	  _GLIBCXX_DEBUG_PEDASSERT(begin() <= __i1 && __i1 <= __i2
+				   && __i2 <= end());
+	  __glibcxx_requires_valid_range(__k1, __k2);
+	  typedef typename std::__is_integer<_InputIterator>::__type _Integral;
+	  return _M_replace_dispatch(__i1, __i2, __k1, __k2, _Integral());
+	}
+#endif
+
+      // Specializations for the common case of pointer and iterator:
+      // useful to avoid the overhead of temporary buffering in _M_replace.
+      _GLIBCXX20_CONSTEXPR
+      basic_string&
+      replace(__const_iterator __i1, __const_iterator __i2,
+	      _CharT* __k1, _CharT* __k2)
+      {
+	_GLIBCXX_DEBUG_PEDASSERT(begin() <= __i1 && __i1 <= __i2
+				 && __i2 <= end());
+	__glibcxx_requires_valid_range(__k1, __k2);
+	return this->replace(__i1 - begin(), __i2 - __i1,
+			     __k1, __k2 - __k1);
+      }
+
+      _GLIBCXX20_CONSTEXPR
+      basic_string&
+      replace(__const_iterator __i1, __const_iterator __i2,
+	      const _CharT* __k1, const _CharT* __k2)
+      {
+	_GLIBCXX_DEBUG_PEDASSERT(begin() <= __i1 && __i1 <= __i2
+				 && __i2 <= end());
+	__glibcxx_requires_valid_range(__k1, __k2);
+	return this->replace(__i1 - begin(), __i2 - __i1,
+			     __k1, __k2 - __k1);
+      }
+
+      _GLIBCXX20_CONSTEXPR
+      basic_string&
+      replace(__const_iterator __i1, __const_iterator __i2,
+	      iterator __k1, iterator __k2)
+      {
+	_GLIBCXX_DEBUG_PEDASSERT(begin() <= __i1 && __i1 <= __i2
+				 && __i2 <= end());
+	__glibcxx_requires_valid_range(__k1, __k2);
+	return this->replace(__i1 - begin(), __i2 - __i1,
+			     __k1.base(), __k2 - __k1);
+      }
+
+      _GLIBCXX20_CONSTEXPR
+      basic_string&
+      replace(__const_iterator __i1, __const_iterator __i2,
+	      const_iterator __k1, const_iterator __k2)
+      {
+	_GLIBCXX_DEBUG_PEDASSERT(begin() <= __i1 && __i1 <= __i2
+				 && __i2 <= end());
+	__glibcxx_requires_valid_range(__k1, __k2);
+	return this->replace(__i1 - begin(), __i2 - __i1,
+			     __k1.base(), __k2 - __k1);
+      }
+
+#if __cplusplus >= 201103L
+      /**
+       *  @brief  Replace range of characters with initializer_list.
+       *  @param __i1  Iterator referencing start of range to replace.
+       *  @param __i2  Iterator referencing end of range to replace.
+       *  @param __l  The initializer_list of characters to insert.
+       *  @return  Reference to this string.
+       *  @throw  std::length_error  If new length exceeds @c max_size().
+       *
+       *  Removes the characters in the range [__i1,__i2).  In place,
+       *  characters in the range [__k1,__k2) are inserted.  If the
+       *  length of result exceeds max_size(), length_error is thrown.
+       *  The value of the string doesn't change if an error is
+       *  thrown.
+      */
+      _GLIBCXX20_CONSTEXPR
+      basic_string& replace(const_iterator __i1, const_iterator __i2,
+			    initializer_list<_CharT> __l)
+      { return this->replace(__i1, __i2, __l.begin(), __l.size()); }
+#endif // C++11
+
+#if __cplusplus >= 201703L
+      /**
+       *  @brief  Replace range of characters with string_view.
+       *  @param __pos  The position to replace at.
+       *  @param __n    The number of characters to replace.
+       *  @param __svt  The object convertible to string_view to insert.
+       *  @return  Reference to this string.
+      */
+      template<typename _Tp>
+	_GLIBCXX20_CONSTEXPR
+	_If_sv<_Tp, basic_string&>
+	replace(size_type __pos, size_type __n, const _Tp& __svt)
+	{
+	  __sv_type __sv = __svt;
+	  return this->replace(__pos, __n, __sv.data(), __sv.size());
+	}
+
+      /**
+       *  @brief  Replace range of characters with string_view.
+       *  @param __pos1  The position to replace at.
+       *  @param __n1    The number of characters to replace.
+       *  @param __svt   The object convertible to string_view to insert from.
+       *  @param __pos2  The position in the string_view to insert from.
+       *  @param __n2    The number of characters to insert.
+       *  @return  Reference to this string.
+      */
+      template<typename _Tp>
+	_GLIBCXX20_CONSTEXPR
+	_If_sv<_Tp, basic_string&>
+	replace(size_type __pos1, size_type __n1, const _Tp& __svt,
+		size_type __pos2, size_type __n2 = npos)
+	{
+	  __sv_type __sv = __svt;
+	  return this->replace(__pos1, __n1,
+	      __sv.data()
+	      + std::__sv_check(__sv.size(), __pos2, "basic_string::replace"),
+	      std::__sv_limit(__sv.size(), __pos2, __n2));
+	}
+
+      /**
+       *  @brief  Replace range of characters with string_view.
+       *  @param __i1    An iterator referencing the start position
+          to replace at.
+       *  @param __i2    An iterator referencing the end position
+          for the replace.
+       *  @param __svt   The object convertible to string_view to insert from.
+       *  @return  Reference to this string.
+      */
+      template<typename _Tp>
+	_GLIBCXX20_CONSTEXPR
+	_If_sv<_Tp, basic_string&>
+	replace(const_iterator __i1, const_iterator __i2, const _Tp& __svt)
+	{
+	  __sv_type __sv = __svt;
+	  return this->replace(__i1 - begin(), __i2 - __i1, __sv);
+	}
+#endif // C++17
+
+    private:
+      template<class _Integer>
+	_GLIBCXX20_CONSTEXPR
+	basic_string&
+	_M_replace_dispatch(const_iterator __i1, const_iterator __i2,
+			    _Integer __n, _Integer __val, __true_type)
+        { return _M_replace_aux(__i1 - begin(), __i2 - __i1, __n, __val); }
+
+      template<class _InputIterator>
+	_GLIBCXX20_CONSTEXPR
+	basic_string&
+	_M_replace_dispatch(const_iterator __i1, const_iterator __i2,
+			    _InputIterator __k1, _InputIterator __k2,
+			    __false_type);
+
+      _GLIBCXX20_CONSTEXPR
+      basic_string&
+      _M_replace_aux(size_type __pos1, size_type __n1, size_type __n2,
+		     _CharT __c);
+
+      _GLIBCXX20_CONSTEXPR
+      basic_string&
+      _M_replace(size_type __pos, size_type __len1, const _CharT* __s,
+		 const size_type __len2);
+
+      _GLIBCXX20_CONSTEXPR
+      basic_string&
+      _M_append(const _CharT* __s, size_type __n);
+
+    public:
+
+      /**
+       *  @brief  Copy substring into C string.
+       *  @param __s  C string to copy value into.
+       *  @param __n  Number of characters to copy.
+       *  @param __pos  Index of first character to copy.
+       *  @return  Number of characters actually copied
+       *  @throw  std::out_of_range  If __pos > size().
+       *
+       *  Copies up to @a __n characters starting at @a __pos into the
+       *  C string @a __s.  If @a __pos is %greater than size(),
+       *  out_of_range is thrown.
+      */
+      _GLIBCXX20_CONSTEXPR
+      size_type
+      copy(_CharT* __s, size_type __n, size_type __pos = 0) const;
+
+      /**
+       *  @brief  Swap contents with another string.
+       *  @param __s  String to swap with.
+       *
+       *  Exchanges the contents of this string with that of @a __s in constant
+       *  time.
+      */
+      _GLIBCXX20_CONSTEXPR
+      void
+      swap(basic_string& __s) _GLIBCXX_NOEXCEPT;
+
+      // String operations:
+      /**
+       *  @brief  Return const pointer to null-terminated contents.
+       *
+       *  This is a handle to internal data.  Do not modify or dire things may
+       *  happen.
+      */
+      _GLIBCXX20_CONSTEXPR
+      const _CharT*
+      c_str() const _GLIBCXX_NOEXCEPT
+      { return _M_data(); }
+
+      /**
+       *  @brief  Return const pointer to contents.
+       *
+       *  This is a pointer to internal data.  It is undefined to modify
+       *  the contents through the returned pointer. To get a pointer that
+       *  allows modifying the contents use @c &str[0] instead,
+       *  (or in C++17 the non-const @c str.data() overload).
+      */
+      _GLIBCXX20_CONSTEXPR
+      const _CharT*
+      data() const _GLIBCXX_NOEXCEPT
+      { return _M_data(); }
+
+#if __cplusplus >= 201703L
+      /**
+       *  @brief  Return non-const pointer to contents.
+       *
+       *  This is a pointer to the character sequence held by the string.
+       *  Modifying the characters in the sequence is allowed.
+      */
+      _GLIBCXX20_CONSTEXPR
+      _CharT*
+      data() noexcept
+      { return _M_data(); }
+#endif
+
+      /**
+       *  @brief  Return copy of allocator used to construct this string.
+      */
+      _GLIBCXX20_CONSTEXPR
+      allocator_type
+      get_allocator() const _GLIBCXX_NOEXCEPT
+      { return _M_get_allocator(); }
+
+      /**
+       *  @brief  Find position of a C substring.
+       *  @param __s  C string to locate.
+       *  @param __pos  Index of character to search from.
+       *  @param __n  Number of characters from @a s to search for.
+       *  @return  Index of start of first occurrence.
+       *
+       *  Starting from @a __pos, searches forward for the first @a
+       *  __n characters in @a __s within this string.  If found,
+       *  returns the index where it begins.  If not found, returns
+       *  npos.
+      */
+      _GLIBCXX20_CONSTEXPR
+      size_type
+      find(const _CharT* __s, size_type __pos, size_type __n) const
+      _GLIBCXX_NOEXCEPT;
+
+      /**
+       *  @brief  Find position of a string.
+       *  @param __str  String to locate.
+       *  @param __pos  Index of character to search from (default 0).
+       *  @return  Index of start of first occurrence.
+       *
+       *  Starting from @a __pos, searches forward for value of @a __str within
+       *  this string.  If found, returns the index where it begins.  If not
+       *  found, returns npos.
+      */
+      _GLIBCXX20_CONSTEXPR
+      size_type
+      find(const basic_string& __str, size_type __pos = 0) const
+      _GLIBCXX_NOEXCEPT
+      { return this->find(__str.data(), __pos, __str.size()); }
+
+#if __cplusplus >= 201703L
+      /**
+       *  @brief  Find position of a string_view.
+       *  @param __svt  The object convertible to string_view to locate.
+       *  @param __pos  Index of character to search from (default 0).
+       *  @return  Index of start of first occurrence.
+      */
+      template<typename _Tp>
+	_GLIBCXX20_CONSTEXPR
+	_If_sv<_Tp, size_type>
+	find(const _Tp& __svt, size_type __pos = 0) const
+	noexcept(is_same<_Tp, __sv_type>::value)
+	{
+	  __sv_type __sv = __svt;
+	  return this->find(__sv.data(), __pos, __sv.size());
+	}
+#endif // C++17
+
+      /**
+       *  @brief  Find position of a C string.
+       *  @param __s  C string to locate.
+       *  @param __pos  Index of character to search from (default 0).
+       *  @return  Index of start of first occurrence.
+       *
+       *  Starting from @a __pos, searches forward for the value of @a
+       *  __s within this string.  If found, returns the index where
+       *  it begins.  If not found, returns npos.
+      */
+      _GLIBCXX20_CONSTEXPR
+      size_type
+      find(const _CharT* __s, size_type __pos = 0) const _GLIBCXX_NOEXCEPT
+      {
+	__glibcxx_requires_string(__s);
+	return this->find(__s, __pos, traits_type::length(__s));
+      }
+
+      /**
+       *  @brief  Find position of a character.
+       *  @param __c  Character to locate.
+       *  @param __pos  Index of character to search from (default 0).
+       *  @return  Index of first occurrence.
+       *
+       *  Starting from @a __pos, searches forward for @a __c within
+       *  this string.  If found, returns the index where it was
+       *  found.  If not found, returns npos.
+      */
+      _GLIBCXX20_CONSTEXPR
+      size_type
+      find(_CharT __c, size_type __pos = 0) const _GLIBCXX_NOEXCEPT;
+
+      /**
+       *  @brief  Find last position of a string.
+       *  @param __str  String to locate.
+       *  @param __pos  Index of character to search back from (default end).
+       *  @return  Index of start of last occurrence.
+       *
+       *  Starting from @a __pos, searches backward for value of @a
+       *  __str within this string.  If found, returns the index where
+       *  it begins.  If not found, returns npos.
+      */
+      _GLIBCXX20_CONSTEXPR
+      size_type
+      rfind(const basic_string& __str, size_type __pos = npos) const
+      _GLIBCXX_NOEXCEPT
+      { return this->rfind(__str.data(), __pos, __str.size()); }
+
+#if __cplusplus >= 201703L
+      /**
+       *  @brief  Find last position of a string_view.
+       *  @param __svt  The object convertible to string_view to locate.
+       *  @param __pos  Index of character to search back from (default end).
+       *  @return  Index of start of last occurrence.
+      */
+      template<typename _Tp>
+	_GLIBCXX20_CONSTEXPR
+	_If_sv<_Tp, size_type>
+	rfind(const _Tp& __svt, size_type __pos = npos) const
+	noexcept(is_same<_Tp, __sv_type>::value)
+	{
+	  __sv_type __sv = __svt;
+	  return this->rfind(__sv.data(), __pos, __sv.size());
+	}
+#endif // C++17
+
+      /**
+       *  @brief  Find last position of a C substring.
+       *  @param __s  C string to locate.
+       *  @param __pos  Index of character to search back from.
+       *  @param __n  Number of characters from s to search for.
+       *  @return  Index of start of last occurrence.
+       *
+       *  Starting from @a __pos, searches backward for the first @a
+       *  __n characters in @a __s within this string.  If found,
+       *  returns the index where it begins.  If not found, returns
+       *  npos.
+      */
+      _GLIBCXX20_CONSTEXPR
+      size_type
+      rfind(const _CharT* __s, size_type __pos, size_type __n) const
+      _GLIBCXX_NOEXCEPT;
+
+      /**
+       *  @brief  Find last position of a C string.
+       *  @param __s  C string to locate.
+       *  @param __pos  Index of character to start search at (default end).
+       *  @return  Index of start of  last occurrence.
+       *
+       *  Starting from @a __pos, searches backward for the value of
+       *  @a __s within this string.  If found, returns the index
+       *  where it begins.  If not found, returns npos.
+      */
+      _GLIBCXX20_CONSTEXPR
+      size_type
+      rfind(const _CharT* __s, size_type __pos = npos) const
+      {
+	__glibcxx_requires_string(__s);
+	return this->rfind(__s, __pos, traits_type::length(__s));
+      }
+
+      /**
+       *  @brief  Find last position of a character.
+       *  @param __c  Character to locate.
+       *  @param __pos  Index of character to search back from (default end).
+       *  @return  Index of last occurrence.
+       *
+       *  Starting from @a __pos, searches backward for @a __c within
+       *  this string.  If found, returns the index where it was
+       *  found.  If not found, returns npos.
+      */
+      _GLIBCXX20_CONSTEXPR
+      size_type
+      rfind(_CharT __c, size_type __pos = npos) const _GLIBCXX_NOEXCEPT;
+
+      /**
+       *  @brief  Find position of a character of string.
+       *  @param __str  String containing characters to locate.
+       *  @param __pos  Index of character to search from (default 0).
+       *  @return  Index of first occurrence.
+       *
+       *  Starting from @a __pos, searches forward for one of the
+       *  characters of @a __str within this string.  If found,
+       *  returns the index where it was found.  If not found, returns
+       *  npos.
+      */
+      _GLIBCXX20_CONSTEXPR
+      size_type
+      find_first_of(const basic_string& __str, size_type __pos = 0) const
+      _GLIBCXX_NOEXCEPT
+      { return this->find_first_of(__str.data(), __pos, __str.size()); }
+
+#if __cplusplus >= 201703L
+      /**
+       *  @brief  Find position of a character of a string_view.
+       *  @param __svt  An object convertible to string_view containing
+       *                characters to locate.
+       *  @param __pos  Index of character to search from (default 0).
+       *  @return  Index of first occurrence.
+      */
+      template<typename _Tp>
+	_GLIBCXX20_CONSTEXPR
+	_If_sv<_Tp, size_type>
+	find_first_of(const _Tp& __svt, size_type __pos = 0) const
+	noexcept(is_same<_Tp, __sv_type>::value)
+	{
+	  __sv_type __sv = __svt;
+	  return this->find_first_of(__sv.data(), __pos, __sv.size());
+	}
+#endif // C++17
+
+      /**
+       *  @brief  Find position of a character of C substring.
+       *  @param __s  String containing characters to locate.
+       *  @param __pos  Index of character to search from.
+       *  @param __n  Number of characters from s to search for.
+       *  @return  Index of first occurrence.
+       *
+       *  Starting from @a __pos, searches forward for one of the
+       *  first @a __n characters of @a __s within this string.  If
+       *  found, returns the index where it was found.  If not found,
+       *  returns npos.
+      */
+      _GLIBCXX20_CONSTEXPR
+      size_type
+      find_first_of(const _CharT* __s, size_type __pos, size_type __n) const
+      _GLIBCXX_NOEXCEPT;
+
+      /**
+       *  @brief  Find position of a character of C string.
+       *  @param __s  String containing characters to locate.
+       *  @param __pos  Index of character to search from (default 0).
+       *  @return  Index of first occurrence.
+       *
+       *  Starting from @a __pos, searches forward for one of the
+       *  characters of @a __s within this string.  If found, returns
+       *  the index where it was found.  If not found, returns npos.
+      */
+      _GLIBCXX20_CONSTEXPR
+      size_type
+      find_first_of(const _CharT* __s, size_type __pos = 0) const
+      _GLIBCXX_NOEXCEPT
+      {
+	__glibcxx_requires_string(__s);
+	return this->find_first_of(__s, __pos, traits_type::length(__s));
+      }
+
+      /**
+       *  @brief  Find position of a character.
+       *  @param __c  Character to locate.
+       *  @param __pos  Index of character to search from (default 0).
+       *  @return  Index of first occurrence.
+       *
+       *  Starting from @a __pos, searches forward for the character
+       *  @a __c within this string.  If found, returns the index
+       *  where it was found.  If not found, returns npos.
+       *
+       *  Note: equivalent to find(__c, __pos).
+      */
+      _GLIBCXX20_CONSTEXPR
+      size_type
+      find_first_of(_CharT __c, size_type __pos = 0) const _GLIBCXX_NOEXCEPT
+      { return this->find(__c, __pos); }
+
+      /**
+       *  @brief  Find last position of a character of string.
+       *  @param __str  String containing characters to locate.
+       *  @param __pos  Index of character to search back from (default end).
+       *  @return  Index of last occurrence.
+       *
+       *  Starting from @a __pos, searches backward for one of the
+       *  characters of @a __str within this string.  If found,
+       *  returns the index where it was found.  If not found, returns
+       *  npos.
+      */
+      _GLIBCXX20_CONSTEXPR
+      size_type
+      find_last_of(const basic_string& __str, size_type __pos = npos) const
+      _GLIBCXX_NOEXCEPT
+      { return this->find_last_of(__str.data(), __pos, __str.size()); }
+
+#if __cplusplus >= 201703L
+      /**
+       *  @brief  Find last position of a character of string.
+       *  @param __svt  An object convertible to string_view containing
+       *                characters to locate.
+       *  @param __pos  Index of character to search back from (default end).
+       *  @return  Index of last occurrence.
+      */
+      template<typename _Tp>
+	_GLIBCXX20_CONSTEXPR
+	_If_sv<_Tp, size_type>
+	find_last_of(const _Tp& __svt, size_type __pos = npos) const
+	noexcept(is_same<_Tp, __sv_type>::value)
+	{
+	  __sv_type __sv = __svt;
+	  return this->find_last_of(__sv.data(), __pos, __sv.size());
+	}
+#endif // C++17
+
+      /**
+       *  @brief  Find last position of a character of C substring.
+       *  @param __s  C string containing characters to locate.
+       *  @param __pos  Index of character to search back from.
+       *  @param __n  Number of characters from s to search for.
+       *  @return  Index of last occurrence.
+       *
+       *  Starting from @a __pos, searches backward for one of the
+       *  first @a __n characters of @a __s within this string.  If
+       *  found, returns the index where it was found.  If not found,
+       *  returns npos.
+      */
+      _GLIBCXX20_CONSTEXPR
+      size_type
+      find_last_of(const _CharT* __s, size_type __pos, size_type __n) const
+      _GLIBCXX_NOEXCEPT;
+
+      /**
+       *  @brief  Find last position of a character of C string.
+       *  @param __s  C string containing characters to locate.
+       *  @param __pos  Index of character to search back from (default end).
+       *  @return  Index of last occurrence.
+       *
+       *  Starting from @a __pos, searches backward for one of the
+       *  characters of @a __s within this string.  If found, returns
+       *  the index where it was found.  If not found, returns npos.
+      */
+      _GLIBCXX20_CONSTEXPR
+      size_type
+      find_last_of(const _CharT* __s, size_type __pos = npos) const
+      _GLIBCXX_NOEXCEPT
+      {
+	__glibcxx_requires_string(__s);
+	return this->find_last_of(__s, __pos, traits_type::length(__s));
+      }
+
+      /**
+       *  @brief  Find last position of a character.
+       *  @param __c  Character to locate.
+       *  @param __pos  Index of character to search back from (default end).
+       *  @return  Index of last occurrence.
+       *
+       *  Starting from @a __pos, searches backward for @a __c within
+       *  this string.  If found, returns the index where it was
+       *  found.  If not found, returns npos.
+       *
+       *  Note: equivalent to rfind(__c, __pos).
+      */
+      _GLIBCXX20_CONSTEXPR
+      size_type
+      find_last_of(_CharT __c, size_type __pos = npos) const _GLIBCXX_NOEXCEPT
+      { return this->rfind(__c, __pos); }
+
+      /**
+       *  @brief  Find position of a character not in string.
+       *  @param __str  String containing characters to avoid.
+       *  @param __pos  Index of character to search from (default 0).
+       *  @return  Index of first occurrence.
+       *
+       *  Starting from @a __pos, searches forward for a character not contained
+       *  in @a __str within this string.  If found, returns the index where it
+       *  was found.  If not found, returns npos.
+      */
+      _GLIBCXX20_CONSTEXPR
+      size_type
+      find_first_not_of(const basic_string& __str, size_type __pos = 0) const
+      _GLIBCXX_NOEXCEPT
+      { return this->find_first_not_of(__str.data(), __pos, __str.size()); }
+
+#if __cplusplus >= 201703L
+      /**
+       *  @brief  Find position of a character not in a string_view.
+       *  @param __svt  A object convertible to string_view containing
+       *                characters to avoid.
+       *  @param __pos  Index of character to search from (default 0).
+       *  @return  Index of first occurrence.
+       */
+      template<typename _Tp>
+	_If_sv<_Tp, size_type>
+	_GLIBCXX20_CONSTEXPR
+	find_first_not_of(const _Tp& __svt, size_type __pos = 0) const
+	noexcept(is_same<_Tp, __sv_type>::value)
+	{
+	  __sv_type __sv = __svt;
+	  return this->find_first_not_of(__sv.data(), __pos, __sv.size());
+	}
+#endif // C++17
+
+      /**
+       *  @brief  Find position of a character not in C substring.
+       *  @param __s  C string containing characters to avoid.
+       *  @param __pos  Index of character to search from.
+       *  @param __n  Number of characters from __s to consider.
+       *  @return  Index of first occurrence.
+       *
+       *  Starting from @a __pos, searches forward for a character not
+       *  contained in the first @a __n characters of @a __s within
+       *  this string.  If found, returns the index where it was
+       *  found.  If not found, returns npos.
+      */
+      _GLIBCXX20_CONSTEXPR
+      size_type
+      find_first_not_of(const _CharT* __s, size_type __pos,
+			size_type __n) const _GLIBCXX_NOEXCEPT;
+
+      /**
+       *  @brief  Find position of a character not in C string.
+       *  @param __s  C string containing characters to avoid.
+       *  @param __pos  Index of character to search from (default 0).
+       *  @return  Index of first occurrence.
+       *
+       *  Starting from @a __pos, searches forward for a character not
+       *  contained in @a __s within this string.  If found, returns
+       *  the index where it was found.  If not found, returns npos.
+      */
+      _GLIBCXX20_CONSTEXPR
+      size_type
+      find_first_not_of(const _CharT* __s, size_type __pos = 0) const
+      _GLIBCXX_NOEXCEPT
+      {
+	__glibcxx_requires_string(__s);
+	return this->find_first_not_of(__s, __pos, traits_type::length(__s));
+      }
+
+      /**
+       *  @brief  Find position of a different character.
+       *  @param __c  Character to avoid.
+       *  @param __pos  Index of character to search from (default 0).
+       *  @return  Index of first occurrence.
+       *
+       *  Starting from @a __pos, searches forward for a character
+       *  other than @a __c within this string.  If found, returns the
+       *  index where it was found.  If not found, returns npos.
+      */
+      _GLIBCXX20_CONSTEXPR
+      size_type
+      find_first_not_of(_CharT __c, size_type __pos = 0) const
+      _GLIBCXX_NOEXCEPT;
+
+      /**
+       *  @brief  Find last position of a character not in string.
+       *  @param __str  String containing characters to avoid.
+       *  @param __pos  Index of character to search back from (default end).
+       *  @return  Index of last occurrence.
+       *
+       *  Starting from @a __pos, searches backward for a character
+       *  not contained in @a __str within this string.  If found,
+       *  returns the index where it was found.  If not found, returns
+       *  npos.
+      */
+      _GLIBCXX20_CONSTEXPR
+      size_type
+      find_last_not_of(const basic_string& __str, size_type __pos = npos) const
+      _GLIBCXX_NOEXCEPT
+      { return this->find_last_not_of(__str.data(), __pos, __str.size()); }
+
+#if __cplusplus >= 201703L
+      /**
+       *  @brief  Find last position of a character not in a string_view.
+       *  @param __svt  An object convertible to string_view containing
+       *                characters to avoid.
+       *  @param __pos  Index of character to search back from (default end).
+       *  @return  Index of last occurrence.
+       */
+      template<typename _Tp>
+	_GLIBCXX20_CONSTEXPR
+	_If_sv<_Tp, size_type>
+	find_last_not_of(const _Tp& __svt, size_type __pos = npos) const
+	noexcept(is_same<_Tp, __sv_type>::value)
+	{
+	  __sv_type __sv = __svt;
+	  return this->find_last_not_of(__sv.data(), __pos, __sv.size());
+	}
+#endif // C++17
+
+      /**
+       *  @brief  Find last position of a character not in C substring.
+       *  @param __s  C string containing characters to avoid.
+       *  @param __pos  Index of character to search back from.
+       *  @param __n  Number of characters from s to consider.
+       *  @return  Index of last occurrence.
+       *
+       *  Starting from @a __pos, searches backward for a character not
+       *  contained in the first @a __n characters of @a __s within this string.
+       *  If found, returns the index where it was found.  If not found,
+       *  returns npos.
+      */
+      _GLIBCXX20_CONSTEXPR
+      size_type
+      find_last_not_of(const _CharT* __s, size_type __pos,
+		       size_type __n) const _GLIBCXX_NOEXCEPT;
+      /**
+       *  @brief  Find last position of a character not in C string.
+       *  @param __s  C string containing characters to avoid.
+       *  @param __pos  Index of character to search back from (default end).
+       *  @return  Index of last occurrence.
+       *
+       *  Starting from @a __pos, searches backward for a character
+       *  not contained in @a __s within this string.  If found,
+       *  returns the index where it was found.  If not found, returns
+       *  npos.
+      */
+      _GLIBCXX20_CONSTEXPR
+      size_type
+      find_last_not_of(const _CharT* __s, size_type __pos = npos) const
+      _GLIBCXX_NOEXCEPT
+      {
+	__glibcxx_requires_string(__s);
+	return this->find_last_not_of(__s, __pos, traits_type::length(__s));
+      }
+
+      /**
+       *  @brief  Find last position of a different character.
+       *  @param __c  Character to avoid.
+       *  @param __pos  Index of character to search back from (default end).
+       *  @return  Index of last occurrence.
+       *
+       *  Starting from @a __pos, searches backward for a character other than
+       *  @a __c within this string.  If found, returns the index where it was
+       *  found.  If not found, returns npos.
+      */
+      _GLIBCXX20_CONSTEXPR
+      size_type
+      find_last_not_of(_CharT __c, size_type __pos = npos) const
+      _GLIBCXX_NOEXCEPT;
+
+      /**
+       *  @brief  Get a substring.
+       *  @param __pos  Index of first character (default 0).
+       *  @param __n  Number of characters in substring (default remainder).
+       *  @return  The new string.
+       *  @throw  std::out_of_range  If __pos > size().
+       *
+       *  Construct and return a new string using the @a __n
+       *  characters starting at @a __pos.  If the string is too
+       *  short, use the remainder of the characters.  If @a __pos is
+       *  beyond the end of the string, out_of_range is thrown.
+      */
+      _GLIBCXX20_CONSTEXPR
+      basic_string
+      substr(size_type __pos = 0, size_type __n = npos) const
+      { return basic_string(*this,
+			    _M_check(__pos, "basic_string::substr"), __n); }
+
+      /**
+       *  @brief  Compare to a string.
+       *  @param __str  String to compare against.
+       *  @return  Integer < 0, 0, or > 0.
+       *
+       *  Returns an integer < 0 if this string is ordered before @a
+       *  __str, 0 if their values are equivalent, or > 0 if this
+       *  string is ordered after @a __str.  Determines the effective
+       *  length rlen of the strings to compare as the smallest of
+       *  size() and str.size().  The function then compares the two
+       *  strings by calling traits::compare(data(), str.data(),rlen).
+       *  If the result of the comparison is nonzero returns it,
+       *  otherwise the shorter one is ordered first.
+      */
+      _GLIBCXX20_CONSTEXPR
+      int
+      compare(const basic_string& __str) const
+      {
+	const size_type __size = this->size();
+	const size_type __osize = __str.size();
+	const size_type __len = std::min(__size, __osize);
+
+	int __r = traits_type::compare(_M_data(), __str.data(), __len);
+	if (!__r)
+	  __r = _S_compare(__size, __osize);
+	return __r;
+      }
+
+#if __cplusplus >= 201703L
+      /**
+       *  @brief  Compare to a string_view.
+       *  @param __svt An object convertible to string_view to compare against.
+       *  @return  Integer < 0, 0, or > 0.
+       */
+      template<typename _Tp>
+	_GLIBCXX20_CONSTEXPR
+	_If_sv<_Tp, int>
+	compare(const _Tp& __svt) const
+	noexcept(is_same<_Tp, __sv_type>::value)
+	{
+	  __sv_type __sv = __svt;
+	  const size_type __size = this->size();
+	  const size_type __osize = __sv.size();
+	  const size_type __len = std::min(__size, __osize);
+
+	  int __r = traits_type::compare(_M_data(), __sv.data(), __len);
+	  if (!__r)
+	    __r = _S_compare(__size, __osize);
+	  return __r;
+	}
+
+      /**
+       *  @brief  Compare to a string_view.
+       *  @param __pos  A position in the string to start comparing from.
+       *  @param __n  The number of characters to compare.
+       *  @param __svt  An object convertible to string_view to compare
+       *                against.
+       *  @return  Integer < 0, 0, or > 0.
+       */
+      template<typename _Tp>
+	_GLIBCXX20_CONSTEXPR
+	_If_sv<_Tp, int>
+	compare(size_type __pos, size_type __n, const _Tp& __svt) const
+	noexcept(is_same<_Tp, __sv_type>::value)
+	{
+	  __sv_type __sv = __svt;
+	  return __sv_type(*this).substr(__pos, __n).compare(__sv);
+	}
+
+      /**
+       *  @brief  Compare to a string_view.
+       *  @param __pos1  A position in the string to start comparing from.
+       *  @param __n1  The number of characters to compare.
+       *  @param __svt  An object convertible to string_view to compare
+       *                against.
+       *  @param __pos2  A position in the string_view to start comparing from.
+       *  @param __n2  The number of characters to compare.
+       *  @return  Integer < 0, 0, or > 0.
+       */
+      template<typename _Tp>
+	_GLIBCXX20_CONSTEXPR
+	_If_sv<_Tp, int>
+	compare(size_type __pos1, size_type __n1, const _Tp& __svt,
+		size_type __pos2, size_type __n2 = npos) const
+	noexcept(is_same<_Tp, __sv_type>::value)
+	{
+	  __sv_type __sv = __svt;
+	  return __sv_type(*this)
+	    .substr(__pos1, __n1).compare(__sv.substr(__pos2, __n2));
+	}
+#endif // C++17
+
+      /**
+       *  @brief  Compare substring to a string.
+       *  @param __pos  Index of first character of substring.
+       *  @param __n  Number of characters in substring.
+       *  @param __str  String to compare against.
+       *  @return  Integer < 0, 0, or > 0.
+       *
+       *  Form the substring of this string from the @a __n characters
+       *  starting at @a __pos.  Returns an integer < 0 if the
+       *  substring is ordered before @a __str, 0 if their values are
+       *  equivalent, or > 0 if the substring is ordered after @a
+       *  __str.  Determines the effective length rlen of the strings
+       *  to compare as the smallest of the length of the substring
+       *  and @a __str.size().  The function then compares the two
+       *  strings by calling
+       *  traits::compare(substring.data(),str.data(),rlen).  If the
+       *  result of the comparison is nonzero returns it, otherwise
+       *  the shorter one is ordered first.
+      */
+      _GLIBCXX20_CONSTEXPR
+      int
+      compare(size_type __pos, size_type __n, const basic_string& __str) const;
+
+      /**
+       *  @brief  Compare substring to a substring.
+       *  @param __pos1  Index of first character of substring.
+       *  @param __n1  Number of characters in substring.
+       *  @param __str  String to compare against.
+       *  @param __pos2  Index of first character of substring of str.
+       *  @param __n2  Number of characters in substring of str.
+       *  @return  Integer < 0, 0, or > 0.
+       *
+       *  Form the substring of this string from the @a __n1
+       *  characters starting at @a __pos1.  Form the substring of @a
+       *  __str from the @a __n2 characters starting at @a __pos2.
+       *  Returns an integer < 0 if this substring is ordered before
+       *  the substring of @a __str, 0 if their values are equivalent,
+       *  or > 0 if this substring is ordered after the substring of
+       *  @a __str.  Determines the effective length rlen of the
+       *  strings to compare as the smallest of the lengths of the
+       *  substrings.  The function then compares the two strings by
+       *  calling
+       *  traits::compare(substring.data(),str.substr(pos2,n2).data(),rlen).
+       *  If the result of the comparison is nonzero returns it,
+       *  otherwise the shorter one is ordered first.
+      */
+      _GLIBCXX20_CONSTEXPR
+      int
+      compare(size_type __pos1, size_type __n1, const basic_string& __str,
+	      size_type __pos2, size_type __n2 = npos) const;
+
+      /**
+       *  @brief  Compare to a C string.
+       *  @param __s  C string to compare against.
+       *  @return  Integer < 0, 0, or > 0.
+       *
+       *  Returns an integer < 0 if this string is ordered before @a __s, 0 if
+       *  their values are equivalent, or > 0 if this string is ordered after
+       *  @a __s.  Determines the effective length rlen of the strings to
+       *  compare as the smallest of size() and the length of a string
+       *  constructed from @a __s.  The function then compares the two strings
+       *  by calling traits::compare(data(),s,rlen).  If the result of the
+       *  comparison is nonzero returns it, otherwise the shorter one is
+       *  ordered first.
+      */
+      _GLIBCXX20_CONSTEXPR
+      int
+      compare(const _CharT* __s) const _GLIBCXX_NOEXCEPT;
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 5 String::compare specification questionable
+      /**
+       *  @brief  Compare substring to a C string.
+       *  @param __pos  Index of first character of substring.
+       *  @param __n1  Number of characters in substring.
+       *  @param __s  C string to compare against.
+       *  @return  Integer < 0, 0, or > 0.
+       *
+       *  Form the substring of this string from the @a __n1
+       *  characters starting at @a pos.  Returns an integer < 0 if
+       *  the substring is ordered before @a __s, 0 if their values
+       *  are equivalent, or > 0 if the substring is ordered after @a
+       *  __s.  Determines the effective length rlen of the strings to
+       *  compare as the smallest of the length of the substring and
+       *  the length of a string constructed from @a __s.  The
+       *  function then compares the two string by calling
+       *  traits::compare(substring.data(),__s,rlen).  If the result of
+       *  the comparison is nonzero returns it, otherwise the shorter
+       *  one is ordered first.
+      */
+      _GLIBCXX20_CONSTEXPR
+      int
+      compare(size_type __pos, size_type __n1, const _CharT* __s) const;
+
+      /**
+       *  @brief  Compare substring against a character %array.
+       *  @param __pos  Index of first character of substring.
+       *  @param __n1  Number of characters in substring.
+       *  @param __s  character %array to compare against.
+       *  @param __n2  Number of characters of s.
+       *  @return  Integer < 0, 0, or > 0.
+       *
+       *  Form the substring of this string from the @a __n1
+       *  characters starting at @a __pos.  Form a string from the
+       *  first @a __n2 characters of @a __s.  Returns an integer < 0
+       *  if this substring is ordered before the string from @a __s,
+       *  0 if their values are equivalent, or > 0 if this substring
+       *  is ordered after the string from @a __s.  Determines the
+       *  effective length rlen of the strings to compare as the
+       *  smallest of the length of the substring and @a __n2.  The
+       *  function then compares the two strings by calling
+       *  traits::compare(substring.data(),s,rlen).  If the result of
+       *  the comparison is nonzero returns it, otherwise the shorter
+       *  one is ordered first.
+       *
+       *  NB: s must have at least n2 characters, &apos;\\0&apos; has
+       *  no special meaning.
+      */
+      _GLIBCXX20_CONSTEXPR
+      int
+      compare(size_type __pos, size_type __n1, const _CharT* __s,
+	      size_type __n2) const;
+
+#if __cplusplus >= 202002L
+      constexpr bool
+      starts_with(basic_string_view<_CharT, _Traits> __x) const noexcept
+      { return __sv_type(this->data(), this->size()).starts_with(__x); }
+
+      constexpr bool
+      starts_with(_CharT __x) const noexcept
+      { return __sv_type(this->data(), this->size()).starts_with(__x); }
+
+      constexpr bool
+      starts_with(const _CharT* __x) const noexcept
+      { return __sv_type(this->data(), this->size()).starts_with(__x); }
+
+      constexpr bool
+      ends_with(basic_string_view<_CharT, _Traits> __x) const noexcept
+      { return __sv_type(this->data(), this->size()).ends_with(__x); }
+
+      constexpr bool
+      ends_with(_CharT __x) const noexcept
+      { return __sv_type(this->data(), this->size()).ends_with(__x); }
+
+      constexpr bool
+      ends_with(const _CharT* __x) const noexcept
+      { return __sv_type(this->data(), this->size()).ends_with(__x); }
+#endif // C++20
+
+#if __cplusplus > 202002L
+      constexpr bool
+      contains(basic_string_view<_CharT, _Traits> __x) const noexcept
+      { return __sv_type(this->data(), this->size()).contains(__x); }
+
+      constexpr bool
+      contains(_CharT __x) const noexcept
+      { return __sv_type(this->data(), this->size()).contains(__x); }
+
+      constexpr bool
+      contains(const _CharT* __x) const noexcept
+      { return __sv_type(this->data(), this->size()).contains(__x); }
+#endif // C++23
+
+      // Allow basic_stringbuf::__xfer_bufptrs to call _M_length:
+      template<typename, typename, typename> friend class basic_stringbuf;
+    };
+_GLIBCXX_END_NAMESPACE_CXX11
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+#endif  // _GLIBCXX_USE_CXX11_ABI
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+#if __cpp_deduction_guides >= 201606
+_GLIBCXX_BEGIN_NAMESPACE_CXX11
+  template<typename _InputIterator, typename _CharT
+	     = typename iterator_traits<_InputIterator>::value_type,
+	   typename _Allocator = allocator<_CharT>,
+	   typename = _RequireInputIter<_InputIterator>,
+	   typename = _RequireAllocator<_Allocator>>
+    basic_string(_InputIterator, _InputIterator, _Allocator = _Allocator())
+      -> basic_string<_CharT, char_traits<_CharT>, _Allocator>;
+
+  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+  // 3075. basic_string needs deduction guides from basic_string_view
+  template<typename _CharT, typename _Traits,
+	   typename _Allocator = allocator<_CharT>,
+	   typename = _RequireAllocator<_Allocator>>
+    basic_string(basic_string_view<_CharT, _Traits>, const _Allocator& = _Allocator())
+      -> basic_string<_CharT, _Traits, _Allocator>;
+
+  template<typename _CharT, typename _Traits,
+	   typename _Allocator = allocator<_CharT>,
+	   typename = _RequireAllocator<_Allocator>>
+    basic_string(basic_string_view<_CharT, _Traits>,
+		 typename basic_string<_CharT, _Traits, _Allocator>::size_type,
+		 typename basic_string<_CharT, _Traits, _Allocator>::size_type,
+		 const _Allocator& = _Allocator())
+      -> basic_string<_CharT, _Traits, _Allocator>;
+_GLIBCXX_END_NAMESPACE_CXX11
+#endif
+
+  // operator+
+  /**
+   *  @brief  Concatenate two strings.
+   *  @param __lhs  First string.
+   *  @param __rhs  Last string.
+   *  @return  New string with value of @a __lhs followed by @a __rhs.
+   */
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    _GLIBCXX20_CONSTEXPR
+    basic_string<_CharT, _Traits, _Alloc>
+    operator+(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
+	      const basic_string<_CharT, _Traits, _Alloc>& __rhs)
+    {
+      basic_string<_CharT, _Traits, _Alloc> __str(__lhs);
+      __str.append(__rhs);
+      return __str;
+    }
+
+  /**
+   *  @brief  Concatenate C string and string.
+   *  @param __lhs  First string.
+   *  @param __rhs  Last string.
+   *  @return  New string with value of @a __lhs followed by @a __rhs.
+   */
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    _GLIBCXX20_CONSTEXPR
+    basic_string<_CharT,_Traits,_Alloc>
+    operator+(const _CharT* __lhs,
+	      const basic_string<_CharT,_Traits,_Alloc>& __rhs);
+
+  /**
+   *  @brief  Concatenate character and string.
+   *  @param __lhs  First string.
+   *  @param __rhs  Last string.
+   *  @return  New string with @a __lhs followed by @a __rhs.
+   */
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    _GLIBCXX20_CONSTEXPR
+    basic_string<_CharT,_Traits,_Alloc>
+    operator+(_CharT __lhs, const basic_string<_CharT,_Traits,_Alloc>& __rhs);
+
+  /**
+   *  @brief  Concatenate string and C string.
+   *  @param __lhs  First string.
+   *  @param __rhs  Last string.
+   *  @return  New string with @a __lhs followed by @a __rhs.
+   */
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    _GLIBCXX20_CONSTEXPR
+    inline basic_string<_CharT, _Traits, _Alloc>
+    operator+(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
+	      const _CharT* __rhs)
+    {
+      basic_string<_CharT, _Traits, _Alloc> __str(__lhs);
+      __str.append(__rhs);
+      return __str;
+    }
+
+  /**
+   *  @brief  Concatenate string and character.
+   *  @param __lhs  First string.
+   *  @param __rhs  Last string.
+   *  @return  New string with @a __lhs followed by @a __rhs.
+   */
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    _GLIBCXX20_CONSTEXPR
+    inline basic_string<_CharT, _Traits, _Alloc>
+    operator+(const basic_string<_CharT, _Traits, _Alloc>& __lhs, _CharT __rhs)
+    {
+      typedef basic_string<_CharT, _Traits, _Alloc>	__string_type;
+      typedef typename __string_type::size_type		__size_type;
+      __string_type __str(__lhs);
+      __str.append(__size_type(1), __rhs);
+      return __str;
+    }
+
+#if __cplusplus >= 201103L
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    _GLIBCXX20_CONSTEXPR
+    inline basic_string<_CharT, _Traits, _Alloc>
+    operator+(basic_string<_CharT, _Traits, _Alloc>&& __lhs,
+	      const basic_string<_CharT, _Traits, _Alloc>& __rhs)
+    { return std::move(__lhs.append(__rhs)); }
+
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    _GLIBCXX20_CONSTEXPR
+    inline basic_string<_CharT, _Traits, _Alloc>
+    operator+(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
+	      basic_string<_CharT, _Traits, _Alloc>&& __rhs)
+    { return std::move(__rhs.insert(0, __lhs)); }
+
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    _GLIBCXX20_CONSTEXPR
+    inline basic_string<_CharT, _Traits, _Alloc>
+    operator+(basic_string<_CharT, _Traits, _Alloc>&& __lhs,
+	      basic_string<_CharT, _Traits, _Alloc>&& __rhs)
+    {
+#if _GLIBCXX_USE_CXX11_ABI
+      using _Alloc_traits = allocator_traits<_Alloc>;
+      bool __use_rhs = false;
+      if _GLIBCXX17_CONSTEXPR (typename _Alloc_traits::is_always_equal{})
+	__use_rhs = true;
+      else if (__lhs.get_allocator() == __rhs.get_allocator())
+	__use_rhs = true;
+      if (__use_rhs)
+#endif
+	{
+	  const auto __size = __lhs.size() + __rhs.size();
+	  if (__size > __lhs.capacity() && __size <= __rhs.capacity())
+	    return std::move(__rhs.insert(0, __lhs));
+	}
+      return std::move(__lhs.append(__rhs));
+    }
+
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    _GLIBCXX20_CONSTEXPR
+    inline basic_string<_CharT, _Traits, _Alloc>
+    operator+(const _CharT* __lhs,
+	      basic_string<_CharT, _Traits, _Alloc>&& __rhs)
+    { return std::move(__rhs.insert(0, __lhs)); }
+
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    _GLIBCXX20_CONSTEXPR
+    inline basic_string<_CharT, _Traits, _Alloc>
+    operator+(_CharT __lhs,
+	      basic_string<_CharT, _Traits, _Alloc>&& __rhs)
+    { return std::move(__rhs.insert(0, 1, __lhs)); }
+
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    _GLIBCXX20_CONSTEXPR
+    inline basic_string<_CharT, _Traits, _Alloc>
+    operator+(basic_string<_CharT, _Traits, _Alloc>&& __lhs,
+	      const _CharT* __rhs)
+    { return std::move(__lhs.append(__rhs)); }
+
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    _GLIBCXX20_CONSTEXPR
+    inline basic_string<_CharT, _Traits, _Alloc>
+    operator+(basic_string<_CharT, _Traits, _Alloc>&& __lhs,
+	      _CharT __rhs)
+    { return std::move(__lhs.append(1, __rhs)); }
+#endif
+
+  // operator ==
+  /**
+   *  @brief  Test equivalence of two strings.
+   *  @param __lhs  First string.
+   *  @param __rhs  Second string.
+   *  @return  True if @a __lhs.compare(@a __rhs) == 0.  False otherwise.
+   */
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    _GLIBCXX20_CONSTEXPR
+    inline bool
+    operator==(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
+	       const basic_string<_CharT, _Traits, _Alloc>& __rhs)
+    _GLIBCXX_NOEXCEPT
+    { return __lhs.compare(__rhs) == 0; }
+
+  template<typename _CharT>
+    _GLIBCXX20_CONSTEXPR
+    inline
+    typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value, bool>::__type
+    operator==(const basic_string<_CharT>& __lhs,
+	       const basic_string<_CharT>& __rhs) _GLIBCXX_NOEXCEPT
+    { return (__lhs.size() == __rhs.size()
+	      && !std::char_traits<_CharT>::compare(__lhs.data(), __rhs.data(),
+						    __lhs.size())); }
+
+  /**
+   *  @brief  Test equivalence of string and C string.
+   *  @param __lhs  String.
+   *  @param __rhs  C string.
+   *  @return  True if @a __lhs.compare(@a __rhs) == 0.  False otherwise.
+   */
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    _GLIBCXX20_CONSTEXPR
+    inline bool
+    operator==(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
+	       const _CharT* __rhs)
+    { return __lhs.compare(__rhs) == 0; }
+
+#if __cpp_lib_three_way_comparison
+  /**
+   *  @brief  Three-way comparison of a string and a C string.
+   *  @param __lhs  A string.
+   *  @param __rhs  A null-terminated string.
+   *  @return  A value indicating whether `__lhs` is less than, equal to,
+   *	       greater than, or incomparable with `__rhs`.
+   */
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    constexpr auto
+    operator<=>(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
+		const basic_string<_CharT, _Traits, _Alloc>& __rhs) noexcept
+    -> decltype(__detail::__char_traits_cmp_cat<_Traits>(0))
+    { return __detail::__char_traits_cmp_cat<_Traits>(__lhs.compare(__rhs)); }
+
+  /**
+   *  @brief  Three-way comparison of a string and a C string.
+   *  @param __lhs  A string.
+   *  @param __rhs  A null-terminated string.
+   *  @return  A value indicating whether `__lhs` is less than, equal to,
+   *	       greater than, or incomparable with `__rhs`.
+   */
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    constexpr auto
+    operator<=>(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
+		const _CharT* __rhs) noexcept
+    -> decltype(__detail::__char_traits_cmp_cat<_Traits>(0))
+    { return __detail::__char_traits_cmp_cat<_Traits>(__lhs.compare(__rhs)); }
+#else
+  /**
+   *  @brief  Test equivalence of C string and string.
+   *  @param __lhs  C string.
+   *  @param __rhs  String.
+   *  @return  True if @a __rhs.compare(@a __lhs) == 0.  False otherwise.
+   */
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    inline bool
+    operator==(const _CharT* __lhs,
+	       const basic_string<_CharT, _Traits, _Alloc>& __rhs)
+    { return __rhs.compare(__lhs) == 0; }
+
+  // operator !=
+  /**
+   *  @brief  Test difference of two strings.
+   *  @param __lhs  First string.
+   *  @param __rhs  Second string.
+   *  @return  True if @a __lhs.compare(@a __rhs) != 0.  False otherwise.
+   */
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    inline bool
+    operator!=(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
+	       const basic_string<_CharT, _Traits, _Alloc>& __rhs)
+    _GLIBCXX_NOEXCEPT
+    { return !(__lhs == __rhs); }
+
+  /**
+   *  @brief  Test difference of C string and string.
+   *  @param __lhs  C string.
+   *  @param __rhs  String.
+   *  @return  True if @a __rhs.compare(@a __lhs) != 0.  False otherwise.
+   */
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    inline bool
+    operator!=(const _CharT* __lhs,
+	       const basic_string<_CharT, _Traits, _Alloc>& __rhs)
+    { return !(__lhs == __rhs); }
+
+  /**
+   *  @brief  Test difference of string and C string.
+   *  @param __lhs  String.
+   *  @param __rhs  C string.
+   *  @return  True if @a __lhs.compare(@a __rhs) != 0.  False otherwise.
+   */
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    inline bool
+    operator!=(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
+	       const _CharT* __rhs)
+    { return !(__lhs == __rhs); }
+
+  // operator <
+  /**
+   *  @brief  Test if string precedes string.
+   *  @param __lhs  First string.
+   *  @param __rhs  Second string.
+   *  @return  True if @a __lhs precedes @a __rhs.  False otherwise.
+   */
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    inline bool
+    operator<(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
+	      const basic_string<_CharT, _Traits, _Alloc>& __rhs)
+    _GLIBCXX_NOEXCEPT
+    { return __lhs.compare(__rhs) < 0; }
+
+  /**
+   *  @brief  Test if string precedes C string.
+   *  @param __lhs  String.
+   *  @param __rhs  C string.
+   *  @return  True if @a __lhs precedes @a __rhs.  False otherwise.
+   */
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    inline bool
+    operator<(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
+	      const _CharT* __rhs)
+    { return __lhs.compare(__rhs) < 0; }
+
+  /**
+   *  @brief  Test if C string precedes string.
+   *  @param __lhs  C string.
+   *  @param __rhs  String.
+   *  @return  True if @a __lhs precedes @a __rhs.  False otherwise.
+   */
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    inline bool
+    operator<(const _CharT* __lhs,
+	      const basic_string<_CharT, _Traits, _Alloc>& __rhs)
+    { return __rhs.compare(__lhs) > 0; }
+
+  // operator >
+  /**
+   *  @brief  Test if string follows string.
+   *  @param __lhs  First string.
+   *  @param __rhs  Second string.
+   *  @return  True if @a __lhs follows @a __rhs.  False otherwise.
+   */
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    inline bool
+    operator>(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
+	      const basic_string<_CharT, _Traits, _Alloc>& __rhs)
+    _GLIBCXX_NOEXCEPT
+    { return __lhs.compare(__rhs) > 0; }
+
+  /**
+   *  @brief  Test if string follows C string.
+   *  @param __lhs  String.
+   *  @param __rhs  C string.
+   *  @return  True if @a __lhs follows @a __rhs.  False otherwise.
+   */
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    inline bool
+    operator>(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
+	      const _CharT* __rhs)
+    { return __lhs.compare(__rhs) > 0; }
+
+  /**
+   *  @brief  Test if C string follows string.
+   *  @param __lhs  C string.
+   *  @param __rhs  String.
+   *  @return  True if @a __lhs follows @a __rhs.  False otherwise.
+   */
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    inline bool
+    operator>(const _CharT* __lhs,
+	      const basic_string<_CharT, _Traits, _Alloc>& __rhs)
+    { return __rhs.compare(__lhs) < 0; }
+
+  // operator <=
+  /**
+   *  @brief  Test if string doesn't follow string.
+   *  @param __lhs  First string.
+   *  @param __rhs  Second string.
+   *  @return  True if @a __lhs doesn't follow @a __rhs.  False otherwise.
+   */
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    inline bool
+    operator<=(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
+	       const basic_string<_CharT, _Traits, _Alloc>& __rhs)
+    _GLIBCXX_NOEXCEPT
+    { return __lhs.compare(__rhs) <= 0; }
+
+  /**
+   *  @brief  Test if string doesn't follow C string.
+   *  @param __lhs  String.
+   *  @param __rhs  C string.
+   *  @return  True if @a __lhs doesn't follow @a __rhs.  False otherwise.
+   */
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    inline bool
+    operator<=(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
+	       const _CharT* __rhs)
+    { return __lhs.compare(__rhs) <= 0; }
+
+  /**
+   *  @brief  Test if C string doesn't follow string.
+   *  @param __lhs  C string.
+   *  @param __rhs  String.
+   *  @return  True if @a __lhs doesn't follow @a __rhs.  False otherwise.
+   */
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    inline bool
+    operator<=(const _CharT* __lhs,
+	       const basic_string<_CharT, _Traits, _Alloc>& __rhs)
+    { return __rhs.compare(__lhs) >= 0; }
+
+  // operator >=
+  /**
+   *  @brief  Test if string doesn't precede string.
+   *  @param __lhs  First string.
+   *  @param __rhs  Second string.
+   *  @return  True if @a __lhs doesn't precede @a __rhs.  False otherwise.
+   */
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    inline bool
+    operator>=(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
+	       const basic_string<_CharT, _Traits, _Alloc>& __rhs)
+    _GLIBCXX_NOEXCEPT
+    { return __lhs.compare(__rhs) >= 0; }
+
+  /**
+   *  @brief  Test if string doesn't precede C string.
+   *  @param __lhs  String.
+   *  @param __rhs  C string.
+   *  @return  True if @a __lhs doesn't precede @a __rhs.  False otherwise.
+   */
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    inline bool
+    operator>=(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
+	       const _CharT* __rhs)
+    { return __lhs.compare(__rhs) >= 0; }
+
+  /**
+   *  @brief  Test if C string doesn't precede string.
+   *  @param __lhs  C string.
+   *  @param __rhs  String.
+   *  @return  True if @a __lhs doesn't precede @a __rhs.  False otherwise.
+   */
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    inline bool
+    operator>=(const _CharT* __lhs,
+	     const basic_string<_CharT, _Traits, _Alloc>& __rhs)
+    { return __rhs.compare(__lhs) <= 0; }
+#endif // three-way comparison
+
+  /**
+   *  @brief  Swap contents of two strings.
+   *  @param __lhs  First string.
+   *  @param __rhs  Second string.
+   *
+   *  Exchanges the contents of @a __lhs and @a __rhs in constant time.
+   */
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    _GLIBCXX20_CONSTEXPR
+    inline void
+    swap(basic_string<_CharT, _Traits, _Alloc>& __lhs,
+	 basic_string<_CharT, _Traits, _Alloc>& __rhs)
+    _GLIBCXX_NOEXCEPT_IF(noexcept(__lhs.swap(__rhs)))
+    { __lhs.swap(__rhs); }
+
+
+  /**
+   *  @brief  Read stream into a string.
+   *  @param __is  Input stream.
+   *  @param __str  Buffer to store into.
+   *  @return  Reference to the input stream.
+   *
+   *  Stores characters from @a __is into @a __str until whitespace is
+   *  found, the end of the stream is encountered, or str.max_size()
+   *  is reached.  If is.width() is non-zero, that is the limit on the
+   *  number of characters stored into @a __str.  Any previous
+   *  contents of @a __str are erased.
+   */
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    basic_istream<_CharT, _Traits>&
+    operator>>(basic_istream<_CharT, _Traits>& __is,
+	       basic_string<_CharT, _Traits, _Alloc>& __str);
+
+  template<>
+    basic_istream<char>&
+    operator>>(basic_istream<char>& __is, basic_string<char>& __str);
+
+  /**
+   *  @brief  Write string to a stream.
+   *  @param __os  Output stream.
+   *  @param __str  String to write out.
+   *  @return  Reference to the output stream.
+   *
+   *  Output characters of @a __str into os following the same rules as for
+   *  writing a C string.
+   */
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    inline basic_ostream<_CharT, _Traits>&
+    operator<<(basic_ostream<_CharT, _Traits>& __os,
+	       const basic_string<_CharT, _Traits, _Alloc>& __str)
+    {
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 586. string inserter not a formatted function
+      return __ostream_insert(__os, __str.data(), __str.size());
+    }
+
+  /**
+   *  @brief  Read a line from stream into a string.
+   *  @param __is  Input stream.
+   *  @param __str  Buffer to store into.
+   *  @param __delim  Character marking end of line.
+   *  @return  Reference to the input stream.
+   *
+   *  Stores characters from @a __is into @a __str until @a __delim is
+   *  found, the end of the stream is encountered, or str.max_size()
+   *  is reached.  Any previous contents of @a __str are erased.  If
+   *  @a __delim is encountered, it is extracted but not stored into
+   *  @a __str.
+   */
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    basic_istream<_CharT, _Traits>&
+    getline(basic_istream<_CharT, _Traits>& __is,
+	    basic_string<_CharT, _Traits, _Alloc>& __str, _CharT __delim);
+
+  /**
+   *  @brief  Read a line from stream into a string.
+   *  @param __is  Input stream.
+   *  @param __str  Buffer to store into.
+   *  @return  Reference to the input stream.
+   *
+   *  Stores characters from is into @a __str until &apos;\n&apos; is
+   *  found, the end of the stream is encountered, or str.max_size()
+   *  is reached.  Any previous contents of @a __str are erased.  If
+   *  end of line is encountered, it is extracted but not stored into
+   *  @a __str.
+   */
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    inline basic_istream<_CharT, _Traits>&
+    getline(basic_istream<_CharT, _Traits>& __is,
+	    basic_string<_CharT, _Traits, _Alloc>& __str)
+    { return std::getline(__is, __str, __is.widen('\n')); }
+
+#if __cplusplus >= 201103L
+  /// Read a line from an rvalue stream into a string.
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    inline basic_istream<_CharT, _Traits>&
+    getline(basic_istream<_CharT, _Traits>&& __is,
+	    basic_string<_CharT, _Traits, _Alloc>& __str, _CharT __delim)
+    { return std::getline(__is, __str, __delim); }
+
+  /// Read a line from an rvalue stream into a string.
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    inline basic_istream<_CharT, _Traits>&
+    getline(basic_istream<_CharT, _Traits>&& __is,
+	    basic_string<_CharT, _Traits, _Alloc>& __str)
+    { return std::getline(__is, __str); }
+#endif
+
+  template<>
+    basic_istream<char>&
+    getline(basic_istream<char>& __in, basic_string<char>& __str,
+	    char __delim);
+
+#ifdef _GLIBCXX_USE_WCHAR_T
+  template<>
+    basic_istream<wchar_t>&
+    getline(basic_istream<wchar_t>& __in, basic_string<wchar_t>& __str,
+	    wchar_t __delim);
+#endif  
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#if __cplusplus >= 201103L
+
+#include <ext/string_conversions.h>
+#include <bits/charconv.h>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+_GLIBCXX_BEGIN_NAMESPACE_CXX11
+
+#if _GLIBCXX_USE_C99_STDLIB
+  // 21.4 Numeric Conversions [string.conversions].
+  inline int
+  stoi(const string& __str, size_t* __idx = 0, int __base = 10)
+  { return __gnu_cxx::__stoa<long, int>(&std::strtol, "stoi", __str.c_str(),
+					__idx, __base); }
+
+  inline long
+  stol(const string& __str, size_t* __idx = 0, int __base = 10)
+  { return __gnu_cxx::__stoa(&std::strtol, "stol", __str.c_str(),
+			     __idx, __base); }
+
+  inline unsigned long
+  stoul(const string& __str, size_t* __idx = 0, int __base = 10)
+  { return __gnu_cxx::__stoa(&std::strtoul, "stoul", __str.c_str(),
+			     __idx, __base); }
+
+  inline long long
+  stoll(const string& __str, size_t* __idx = 0, int __base = 10)
+  { return __gnu_cxx::__stoa(&std::strtoll, "stoll", __str.c_str(),
+			     __idx, __base); }
+
+  inline unsigned long long
+  stoull(const string& __str, size_t* __idx = 0, int __base = 10)
+  { return __gnu_cxx::__stoa(&std::strtoull, "stoull", __str.c_str(),
+			     __idx, __base); }
+
+  // NB: strtof vs strtod.
+  inline float
+  stof(const string& __str, size_t* __idx = 0)
+  { return __gnu_cxx::__stoa(&std::strtof, "stof", __str.c_str(), __idx); }
+
+  inline double
+  stod(const string& __str, size_t* __idx = 0)
+  { return __gnu_cxx::__stoa(&std::strtod, "stod", __str.c_str(), __idx); }
+
+  inline long double
+  stold(const string& __str, size_t* __idx = 0)
+  { return __gnu_cxx::__stoa(&std::strtold, "stold", __str.c_str(), __idx); }
+#endif // _GLIBCXX_USE_C99_STDLIB
+
+  // DR 1261. Insufficent overloads for to_string / to_wstring
+
+  inline string
+  to_string(int __val)
+#if _GLIBCXX_USE_CXX11_ABI && (__CHAR_BIT__ * __SIZEOF_INT__) <= 32
+  noexcept // any 32-bit value fits in the SSO buffer
+#endif
+  {
+    const bool __neg = __val < 0;
+    const unsigned __uval = __neg ? (unsigned)~__val + 1u : __val;
+    const auto __len = __detail::__to_chars_len(__uval);
+    string __str(__neg + __len, '-');
+    __detail::__to_chars_10_impl(&__str[__neg], __len, __uval);
+    return __str;
+  }
+
+  inline string
+  to_string(unsigned __val)
+#if _GLIBCXX_USE_CXX11_ABI && (__CHAR_BIT__ * __SIZEOF_INT__) <= 32
+  noexcept // any 32-bit value fits in the SSO buffer
+#endif
+  {
+    string __str(__detail::__to_chars_len(__val), '\0');
+    __detail::__to_chars_10_impl(&__str[0], __str.size(), __val);
+    return __str;
+  }
+
+  inline string
+  to_string(long __val)
+#if _GLIBCXX_USE_CXX11_ABI && (__CHAR_BIT__ * __SIZEOF_LONG__) <= 32
+  noexcept // any 32-bit value fits in the SSO buffer
+#endif
+  {
+    const bool __neg = __val < 0;
+    const unsigned long __uval = __neg ? (unsigned long)~__val + 1ul : __val;
+    const auto __len = __detail::__to_chars_len(__uval);
+    string __str(__neg + __len, '-');
+    __detail::__to_chars_10_impl(&__str[__neg], __len, __uval);
+    return __str;
+  }
+
+  inline string
+  to_string(unsigned long __val)
+#if _GLIBCXX_USE_CXX11_ABI && (__CHAR_BIT__ * __SIZEOF_LONG__) <= 32
+  noexcept // any 32-bit value fits in the SSO buffer
+#endif
+  {
+    string __str(__detail::__to_chars_len(__val), '\0');
+    __detail::__to_chars_10_impl(&__str[0], __str.size(), __val);
+    return __str;
+  }
+
+  inline string
+  to_string(long long __val)
+  {
+    const bool __neg = __val < 0;
+    const unsigned long long __uval
+      = __neg ? (unsigned long long)~__val + 1ull : __val;
+    const auto __len = __detail::__to_chars_len(__uval);
+    string __str(__neg + __len, '-');
+    __detail::__to_chars_10_impl(&__str[__neg], __len, __uval);
+    return __str;
+  }
+
+  inline string
+  to_string(unsigned long long __val)
+  {
+    string __str(__detail::__to_chars_len(__val), '\0');
+    __detail::__to_chars_10_impl(&__str[0], __str.size(), __val);
+    return __str;
+  }
+
+#if _GLIBCXX_USE_C99_STDIO
+  // NB: (v)snprintf vs sprintf.
+
+  inline string
+  to_string(float __val)
+  {
+    const int __n = 
+      __gnu_cxx::__numeric_traits<float>::__max_exponent10 + 20;
+    return __gnu_cxx::__to_xstring<string>(&std::vsnprintf, __n,
+					   "%f", __val);
+  }
+
+  inline string
+  to_string(double __val)
+  {
+    const int __n = 
+      __gnu_cxx::__numeric_traits<double>::__max_exponent10 + 20;
+    return __gnu_cxx::__to_xstring<string>(&std::vsnprintf, __n,
+					   "%f", __val);
+  }
+
+  inline string
+  to_string(long double __val)
+  {
+    const int __n = 
+      __gnu_cxx::__numeric_traits<long double>::__max_exponent10 + 20;
+    return __gnu_cxx::__to_xstring<string>(&std::vsnprintf, __n,
+					   "%Lf", __val);
+  }
+#endif // _GLIBCXX_USE_C99_STDIO
+
+#if defined(_GLIBCXX_USE_WCHAR_T) && _GLIBCXX_USE_C99_WCHAR
+  inline int 
+  stoi(const wstring& __str, size_t* __idx = 0, int __base = 10)
+  { return __gnu_cxx::__stoa<long, int>(&std::wcstol, "stoi", __str.c_str(),
+					__idx, __base); }
+
+  inline long 
+  stol(const wstring& __str, size_t* __idx = 0, int __base = 10)
+  { return __gnu_cxx::__stoa(&std::wcstol, "stol", __str.c_str(),
+			     __idx, __base); }
+
+  inline unsigned long
+  stoul(const wstring& __str, size_t* __idx = 0, int __base = 10)
+  { return __gnu_cxx::__stoa(&std::wcstoul, "stoul", __str.c_str(),
+			     __idx, __base); }
+
+  inline long long
+  stoll(const wstring& __str, size_t* __idx = 0, int __base = 10)
+  { return __gnu_cxx::__stoa(&std::wcstoll, "stoll", __str.c_str(),
+			     __idx, __base); }
+
+  inline unsigned long long
+  stoull(const wstring& __str, size_t* __idx = 0, int __base = 10)
+  { return __gnu_cxx::__stoa(&std::wcstoull, "stoull", __str.c_str(),
+			     __idx, __base); }
+
+  // NB: wcstof vs wcstod.
+  inline float
+  stof(const wstring& __str, size_t* __idx = 0)
+  { return __gnu_cxx::__stoa(&std::wcstof, "stof", __str.c_str(), __idx); }
+
+  inline double
+  stod(const wstring& __str, size_t* __idx = 0)
+  { return __gnu_cxx::__stoa(&std::wcstod, "stod", __str.c_str(), __idx); }
+
+  inline long double
+  stold(const wstring& __str, size_t* __idx = 0)
+  { return __gnu_cxx::__stoa(&std::wcstold, "stold", __str.c_str(), __idx); }
+
+#ifndef _GLIBCXX_HAVE_BROKEN_VSWPRINTF
+  // DR 1261.
+  inline wstring
+  to_wstring(int __val)
+  { return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf, 4 * sizeof(int),
+					    L"%d", __val); }
+
+  inline wstring
+  to_wstring(unsigned __val)
+  { return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf,
+					    4 * sizeof(unsigned),
+					    L"%u", __val); }
+
+  inline wstring
+  to_wstring(long __val)
+  { return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf, 4 * sizeof(long),
+					    L"%ld", __val); }
+
+  inline wstring
+  to_wstring(unsigned long __val)
+  { return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf,
+					    4 * sizeof(unsigned long),
+					    L"%lu", __val); }
+
+  inline wstring
+  to_wstring(long long __val)
+  { return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf,
+					    4 * sizeof(long long),
+					    L"%lld", __val); }
+
+  inline wstring
+  to_wstring(unsigned long long __val)
+  { return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf,
+					    4 * sizeof(unsigned long long),
+					    L"%llu", __val); }
+
+  inline wstring
+  to_wstring(float __val)
+  {
+    const int __n =
+      __gnu_cxx::__numeric_traits<float>::__max_exponent10 + 20;
+    return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf, __n,
+					    L"%f", __val);
+  }
+
+  inline wstring
+  to_wstring(double __val)
+  {
+    const int __n =
+      __gnu_cxx::__numeric_traits<double>::__max_exponent10 + 20;
+    return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf, __n,
+					    L"%f", __val);
+  }
+
+  inline wstring
+  to_wstring(long double __val)
+  {
+    const int __n =
+      __gnu_cxx::__numeric_traits<long double>::__max_exponent10 + 20;
+    return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf, __n,
+					    L"%Lf", __val);
+  }
+#endif // _GLIBCXX_HAVE_BROKEN_VSWPRINTF
+#endif // _GLIBCXX_USE_WCHAR_T && _GLIBCXX_USE_C99_WCHAR
+
+_GLIBCXX_END_NAMESPACE_CXX11
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif /* C++11 */
+
+#if __cplusplus >= 201103L
+
+#include <bits/functional_hash.h>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  // DR 1182.
+
+#ifndef _GLIBCXX_COMPATIBILITY_CXX0X
+  /// std::hash specialization for string.
+  template<>
+    struct hash<string>
+    : public __hash_base<size_t, string>
+    {
+      size_t
+      operator()(const string& __s) const noexcept
+      { return std::_Hash_impl::hash(__s.data(), __s.length()); }
+    };
+
+  template<>
+    struct __is_fast_hash<hash<string>> : std::false_type
+    { };
+
+  /// std::hash specialization for wstring.
+  template<>
+    struct hash<wstring>
+    : public __hash_base<size_t, wstring>
+    {
+      size_t
+      operator()(const wstring& __s) const noexcept
+      { return std::_Hash_impl::hash(__s.data(),
+                                     __s.length() * sizeof(wchar_t)); }
+    };
+
+  template<>
+    struct __is_fast_hash<hash<wstring>> : std::false_type
+    { };
+#endif /* _GLIBCXX_COMPATIBILITY_CXX0X */
+
+#ifdef _GLIBCXX_USE_CHAR8_T
+  /// std::hash specialization for u8string.
+  template<>
+    struct hash<u8string>
+    : public __hash_base<size_t, u8string>
+    {
+      size_t
+      operator()(const u8string& __s) const noexcept
+      { return std::_Hash_impl::hash(__s.data(),
+                                     __s.length() * sizeof(char8_t)); }
+    };
+
+  template<>
+    struct __is_fast_hash<hash<u8string>> : std::false_type
+    { };
+#endif
+
+  /// std::hash specialization for u16string.
+  template<>
+    struct hash<u16string>
+    : public __hash_base<size_t, u16string>
+    {
+      size_t
+      operator()(const u16string& __s) const noexcept
+      { return std::_Hash_impl::hash(__s.data(),
+                                     __s.length() * sizeof(char16_t)); }
+    };
+
+  template<>
+    struct __is_fast_hash<hash<u16string>> : std::false_type
+    { };
+
+  /// std::hash specialization for u32string.
+  template<>
+    struct hash<u32string>
+    : public __hash_base<size_t, u32string>
+    {
+      size_t
+      operator()(const u32string& __s) const noexcept
+      { return std::_Hash_impl::hash(__s.data(),
+                                     __s.length() * sizeof(char32_t)); }
+    };
+
+  template<>
+    struct __is_fast_hash<hash<u32string>> : std::false_type
+    { };
+
+#if __cplusplus >= 201402L
+
+#define __cpp_lib_string_udls 201304L
+
+  inline namespace literals
+  {
+  inline namespace string_literals
+  {
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wliteral-suffix"
+
+#if __cpp_lib_constexpr_string >= 201907L
+# define _GLIBCXX_STRING_CONSTEXPR constexpr
+#else
+# define _GLIBCXX_STRING_CONSTEXPR
+#endif
+
+    _GLIBCXX_DEFAULT_ABI_TAG _GLIBCXX_STRING_CONSTEXPR
+    inline basic_string<char>
+    operator""s(const char* __str, size_t __len)
+    { return basic_string<char>{__str, __len}; }
+
+    _GLIBCXX_DEFAULT_ABI_TAG _GLIBCXX_STRING_CONSTEXPR
+    inline basic_string<wchar_t>
+    operator""s(const wchar_t* __str, size_t __len)
+    { return basic_string<wchar_t>{__str, __len}; }
+
+#ifdef _GLIBCXX_USE_CHAR8_T
+    _GLIBCXX_DEFAULT_ABI_TAG _GLIBCXX_STRING_CONSTEXPR
+    inline basic_string<char8_t>
+    operator""s(const char8_t* __str, size_t __len)
+    { return basic_string<char8_t>{__str, __len}; }
+#endif
+
+    _GLIBCXX_DEFAULT_ABI_TAG _GLIBCXX_STRING_CONSTEXPR
+    inline basic_string<char16_t>
+    operator""s(const char16_t* __str, size_t __len)
+    { return basic_string<char16_t>{__str, __len}; }
+
+    _GLIBCXX_DEFAULT_ABI_TAG _GLIBCXX_STRING_CONSTEXPR
+    inline basic_string<char32_t>
+    operator""s(const char32_t* __str, size_t __len)
+    { return basic_string<char32_t>{__str, __len}; }
+
+#undef _GLIBCXX_STRING_CONSTEXPR
+#pragma GCC diagnostic pop
+  } // inline namespace string_literals
+  } // inline namespace literals
+
+#if __cplusplus >= 201703L
+  namespace __detail::__variant
+  {
+    template<typename> struct _Never_valueless_alt; // see <variant>
+
+    // Provide the strong exception-safety guarantee when emplacing a
+    // basic_string into a variant, but only if moving the string cannot throw.
+    template<typename _Tp, typename _Traits, typename _Alloc>
+      struct _Never_valueless_alt<std::basic_string<_Tp, _Traits, _Alloc>>
+      : __and_<
+	is_nothrow_move_constructible<std::basic_string<_Tp, _Traits, _Alloc>>,
+	is_nothrow_move_assignable<std::basic_string<_Tp, _Traits, _Alloc>>
+	>::type
+      { };
+  }  // namespace __detail::__variant
+#endif // C++17
+#endif // C++14
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif // C++11
+
+#endif /* _BASIC_STRING_H */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@basic_string.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@basic_string.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@basic_string.tcc b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@basic_string.tcc
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@basic_string.tcc
@@ -0,0 +1,1129 @@
+// Components for manipulating sequences of characters -*- C++ -*-
+
+// Copyright (C) 1997-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/basic_string.tcc
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{string}
+ */
+
+//
+// ISO C++ 14882: 21  Strings library
+//
+
+// Written by Jason Merrill based upon the specification by Takanori Adachi
+// in ANSI X3J16/94-0013R2.  Rewritten by Nathan Myers to ISO-14882.
+// Non-reference-counted implementation written by Paolo Carlini and
+// updated by Jonathan Wakely for ISO-14882-2011.
+
+#ifndef _BASIC_STRING_TCC
+#define _BASIC_STRING_TCC 1
+
+#pragma GCC system_header
+
+#include <bits/cxxabi_forced.h>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+#if _GLIBCXX_USE_CXX11_ABI
+
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    const typename basic_string<_CharT, _Traits, _Alloc>::size_type
+    basic_string<_CharT, _Traits, _Alloc>::npos;
+
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    _GLIBCXX20_CONSTEXPR
+    void
+    basic_string<_CharT, _Traits, _Alloc>::
+    swap(basic_string& __s) _GLIBCXX_NOEXCEPT
+    {
+      if (this == std::__addressof(__s))
+	return;
+
+      _Alloc_traits::_S_on_swap(_M_get_allocator(), __s._M_get_allocator());
+
+      if (_M_is_local())
+	if (__s._M_is_local())
+	  {
+	    if (length() && __s.length())
+	      {
+		_CharT __tmp_data[_S_local_capacity + 1];
+		traits_type::copy(__tmp_data, __s._M_local_buf,
+				  __s.length() + 1);
+		traits_type::copy(__s._M_local_buf, _M_local_buf,
+				  length() + 1);
+		traits_type::copy(_M_local_buf, __tmp_data,
+				  __s.length() + 1);
+	      }
+	    else if (__s.length())
+	      {
+		traits_type::copy(_M_local_buf, __s._M_local_buf,
+				  __s.length() + 1);
+		_M_length(__s.length());
+		__s._M_set_length(0);
+		return;
+	      }
+	    else if (length())
+	      {
+		traits_type::copy(__s._M_local_buf, _M_local_buf,
+				  length() + 1);
+		__s._M_length(length());
+		_M_set_length(0);
+		return;
+	      }
+	  }
+	else
+	  {
+	    const size_type __tmp_capacity = __s._M_allocated_capacity;
+	    traits_type::copy(__s._M_local_buf, _M_local_buf,
+			      length() + 1);
+	    _M_data(__s._M_data());
+	    __s._M_data(__s._M_local_buf);
+	    _M_capacity(__tmp_capacity);
+	  }
+      else
+	{
+	  const size_type __tmp_capacity = _M_allocated_capacity;
+	  if (__s._M_is_local())
+	    {
+	      traits_type::copy(_M_local_buf, __s._M_local_buf,
+				__s.length() + 1);
+	      __s._M_data(_M_data());
+	      _M_data(_M_local_buf);
+	    }
+	  else
+	    {
+	      pointer __tmp_ptr = _M_data();
+	      _M_data(__s._M_data());
+	      __s._M_data(__tmp_ptr);
+	      _M_capacity(__s._M_allocated_capacity);
+	    }
+	  __s._M_capacity(__tmp_capacity);
+	}
+
+      const size_type __tmp_length = length();
+      _M_length(__s.length());
+      __s._M_length(__tmp_length);
+    }
+
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    _GLIBCXX20_CONSTEXPR
+    typename basic_string<_CharT, _Traits, _Alloc>::pointer
+    basic_string<_CharT, _Traits, _Alloc>::
+    _M_create(size_type& __capacity, size_type __old_capacity)
+    {
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 83.  String::npos vs. string::max_size()
+      if (__capacity > max_size())
+	std::__throw_length_error(__N("basic_string::_M_create"));
+
+      // The below implements an exponential growth policy, necessary to
+      // meet amortized linear time requirements of the library: see
+      // http://gcc.gnu.org/ml/libstdc++/2001-07/msg00085.html.
+      if (__capacity > __old_capacity && __capacity < 2 * __old_capacity)
+	{
+	  __capacity = 2 * __old_capacity;
+	  // Never allocate a string bigger than max_size.
+	  if (__capacity > max_size())
+	    __capacity = max_size();
+	}
+
+      // NB: Need an array of char_type[__capacity], plus a terminating
+      // null char_type() element.
+      return _Alloc_traits::allocate(_M_get_allocator(), __capacity + 1);
+    }
+
+  // NB: This is the special case for Input Iterators, used in
+  // istreambuf_iterators, etc.
+  // Input Iterators have a cost structure very different from
+  // pointers, calling for a different coding style.
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    template<typename _InIterator>
+      _GLIBCXX20_CONSTEXPR
+      void
+      basic_string<_CharT, _Traits, _Alloc>::
+      _M_construct(_InIterator __beg, _InIterator __end,
+		   std::input_iterator_tag)
+      {
+	size_type __len = 0;
+	size_type __capacity = size_type(_S_local_capacity);
+
+	pointer __p = _M_use_local_data();
+
+	while (__beg != __end && __len < __capacity)
+	  {
+	    __p[__len++] = *__beg;
+	    ++__beg;
+	  }
+
+	struct _Guard
+	{
+	  _GLIBCXX20_CONSTEXPR
+	  explicit _Guard(basic_string* __s) : _M_guarded(__s) { }
+
+	  _GLIBCXX20_CONSTEXPR
+	  ~_Guard() { if (_M_guarded) _M_guarded->_M_dispose(); }
+
+	  basic_string* _M_guarded;
+	} __guard(this);
+
+	while (__beg != __end)
+	  {
+	    if (__len == __capacity)
+	      {
+		// Allocate more space.
+		__capacity = __len + 1;
+		pointer __another = _M_create(__capacity, __len);
+		this->_S_copy(__another, _M_data(), __len);
+		_M_dispose();
+		_M_data(__another);
+		_M_capacity(__capacity);
+	      }
+	    traits_type::assign(_M_data()[__len++], *__beg);
+	    ++__beg;
+	  }
+
+	__guard._M_guarded = 0;
+
+	_M_set_length(__len);
+      }
+
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    template<typename _InIterator>
+      _GLIBCXX20_CONSTEXPR
+      void
+      basic_string<_CharT, _Traits, _Alloc>::
+      _M_construct(_InIterator __beg, _InIterator __end,
+		   std::forward_iterator_tag)
+      {
+	size_type __dnew = static_cast<size_type>(std::distance(__beg, __end));
+
+	if (__dnew > size_type(_S_local_capacity))
+	  {
+	    _M_data(_M_create(__dnew, size_type(0)));
+	    _M_capacity(__dnew);
+	  }
+	else
+	  _M_use_local_data();
+
+	// Check for out_of_range and length_error exceptions.
+	struct _Guard
+	{
+	  _GLIBCXX20_CONSTEXPR
+	  explicit _Guard(basic_string* __s) : _M_guarded(__s) { }
+
+	  _GLIBCXX20_CONSTEXPR
+	  ~_Guard() { if (_M_guarded) _M_guarded->_M_dispose(); }
+
+	  basic_string* _M_guarded;
+	} __guard(this);
+
+	this->_S_copy_chars(_M_data(), __beg, __end);
+
+	__guard._M_guarded = 0;
+
+	_M_set_length(__dnew);
+      }
+
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    _GLIBCXX20_CONSTEXPR
+    void
+    basic_string<_CharT, _Traits, _Alloc>::
+    _M_construct(size_type __n, _CharT __c)
+    {
+      if (__n > size_type(_S_local_capacity))
+	{
+	  _M_data(_M_create(__n, size_type(0)));
+	  _M_capacity(__n);
+	}
+      else
+	_M_use_local_data();
+
+      if (__n)
+	this->_S_assign(_M_data(), __n, __c);
+
+      _M_set_length(__n);
+    }
+
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    _GLIBCXX20_CONSTEXPR
+    void
+    basic_string<_CharT, _Traits, _Alloc>::
+    _M_assign(const basic_string& __str)
+    {
+      if (this != std::__addressof(__str))
+	{
+	  const size_type __rsize = __str.length();
+	  const size_type __capacity = capacity();
+
+	  if (__rsize > __capacity)
+	    {
+	      size_type __new_capacity = __rsize;
+	      pointer __tmp = _M_create(__new_capacity, __capacity);
+	      _M_dispose();
+	      _M_data(__tmp);
+	      _M_capacity(__new_capacity);
+	    }
+
+	  if (__rsize)
+	    this->_S_copy(_M_data(), __str._M_data(), __rsize);
+
+	  _M_set_length(__rsize);
+	}
+    }
+
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    _GLIBCXX20_CONSTEXPR
+    void
+    basic_string<_CharT, _Traits, _Alloc>::
+    reserve(size_type __res)
+    {
+      const size_type __capacity = capacity();
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 2968. Inconsistencies between basic_string reserve and
+      // vector/unordered_map/unordered_set reserve functions
+      // P0966 reserve should not shrink
+      if (__res <= __capacity)
+	return;
+
+      pointer __tmp = _M_create(__res, __capacity);
+      this->_S_copy(__tmp, _M_data(), length() + 1);
+      _M_dispose();
+      _M_data(__tmp);
+      _M_capacity(__res);
+    }
+
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    _GLIBCXX20_CONSTEXPR
+    void
+    basic_string<_CharT, _Traits, _Alloc>::
+    _M_mutate(size_type __pos, size_type __len1, const _CharT* __s,
+	      size_type __len2)
+    {
+      const size_type __how_much = length() - __pos - __len1;
+
+      size_type __new_capacity = length() + __len2 - __len1;
+      pointer __r = _M_create(__new_capacity, capacity());
+
+      if (__pos)
+	this->_S_copy(__r, _M_data(), __pos);
+      if (__s && __len2)
+	this->_S_copy(__r + __pos, __s, __len2);
+      if (__how_much)
+	this->_S_copy(__r + __pos + __len2,
+		      _M_data() + __pos + __len1, __how_much);
+
+      _M_dispose();
+      _M_data(__r);
+      _M_capacity(__new_capacity);
+    }
+
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    _GLIBCXX20_CONSTEXPR
+    void
+    basic_string<_CharT, _Traits, _Alloc>::
+    _M_erase(size_type __pos, size_type __n)
+    {
+      const size_type __how_much = length() - __pos - __n;
+
+      if (__how_much && __n)
+	this->_S_move(_M_data() + __pos, _M_data() + __pos + __n, __how_much);
+
+      _M_set_length(length() - __n);
+    }
+
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    _GLIBCXX20_CONSTEXPR
+    void
+    basic_string<_CharT, _Traits, _Alloc>::
+    reserve()
+    {
+      if (_M_is_local())
+	return;
+
+      const size_type __length = length();
+      const size_type __capacity = _M_allocated_capacity;
+
+      if (__length <= size_type(_S_local_capacity))
+	{
+	  this->_S_copy(_M_use_local_data(), _M_data(), __length + 1);
+	  _M_destroy(__capacity);
+	  _M_data(_M_local_data());
+	}
+#if __cpp_exceptions
+      else if (__length < __capacity)
+	try
+	  {
+	    pointer __tmp
+	      = _Alloc_traits::allocate(_M_get_allocator(), __length + 1);
+	    this->_S_copy(__tmp, _M_data(), __length + 1);
+	    _M_dispose();
+	    _M_data(__tmp);
+	    _M_capacity(__length);
+	  }
+	catch (const __cxxabiv1::__forced_unwind&)
+	  { throw; }
+	catch (...)
+	  { /* swallow the exception */ }
+#endif
+    }
+
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    _GLIBCXX20_CONSTEXPR
+    void
+    basic_string<_CharT, _Traits, _Alloc>::
+    resize(size_type __n, _CharT __c)
+    {
+      const size_type __size = this->size();
+      if (__size < __n)
+	this->append(__n - __size, __c);
+      else if (__n < __size)
+	this->_M_set_length(__n);
+    }
+
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    _GLIBCXX20_CONSTEXPR
+    basic_string<_CharT, _Traits, _Alloc>&
+    basic_string<_CharT, _Traits, _Alloc>::
+    _M_append(const _CharT* __s, size_type __n)
+    {
+      const size_type __len = __n + this->size();
+
+      if (__len <= this->capacity())
+	{
+	  if (__n)
+	    this->_S_copy(this->_M_data() + this->size(), __s, __n);
+	}
+      else
+	this->_M_mutate(this->size(), size_type(0), __s, __n);
+
+      this->_M_set_length(__len);
+      return *this;
+    }
+
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    template<typename _InputIterator>
+      _GLIBCXX20_CONSTEXPR
+      basic_string<_CharT, _Traits, _Alloc>&
+      basic_string<_CharT, _Traits, _Alloc>::
+      _M_replace_dispatch(const_iterator __i1, const_iterator __i2,
+			  _InputIterator __k1, _InputIterator __k2,
+			  std::__false_type)
+      {
+	// _GLIBCXX_RESOLVE_LIB_DEFECTS
+	// 2788. unintentionally require a default constructible allocator
+	const basic_string __s(__k1, __k2, this->get_allocator());
+	const size_type __n1 = __i2 - __i1;
+	return _M_replace(__i1 - begin(), __n1, __s._M_data(),
+			  __s.size());
+      }
+
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    _GLIBCXX20_CONSTEXPR
+    basic_string<_CharT, _Traits, _Alloc>&
+    basic_string<_CharT, _Traits, _Alloc>::
+    _M_replace_aux(size_type __pos1, size_type __n1, size_type __n2,
+		   _CharT __c)
+    {
+      _M_check_length(__n1, __n2, "basic_string::_M_replace_aux");
+
+      const size_type __old_size = this->size();
+      const size_type __new_size = __old_size + __n2 - __n1;
+
+      if (__new_size <= this->capacity())
+	{
+	  pointer __p = this->_M_data() + __pos1;
+
+	  const size_type __how_much = __old_size - __pos1 - __n1;
+	  if (__how_much && __n1 != __n2)
+	    this->_S_move(__p + __n2, __p + __n1, __how_much);
+	}
+      else
+	this->_M_mutate(__pos1, __n1, 0, __n2);
+
+      if (__n2)
+	this->_S_assign(this->_M_data() + __pos1, __n2, __c);
+
+      this->_M_set_length(__new_size);
+      return *this;
+    }
+
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    _GLIBCXX20_CONSTEXPR
+    basic_string<_CharT, _Traits, _Alloc>&
+    basic_string<_CharT, _Traits, _Alloc>::
+    _M_replace(size_type __pos, size_type __len1, const _CharT* __s,
+	       const size_type __len2)
+    {
+      _M_check_length(__len1, __len2, "basic_string::_M_replace");
+
+      const size_type __old_size = this->size();
+      const size_type __new_size = __old_size + __len2 - __len1;
+
+      if (__new_size <= this->capacity())
+	{
+	  pointer __p = this->_M_data() + __pos;
+
+	  const size_type __how_much = __old_size - __pos - __len1;
+#if __cpp_lib_is_constant_evaluated
+	  if (std::is_constant_evaluated())
+	    {
+	      auto __newp = _Alloc_traits::allocate(_M_get_allocator(),
+						    __new_size);
+	      _S_copy(__newp, this->_M_data(), __pos);
+	      _S_copy(__newp + __pos, __s, __len2);
+	      _S_copy(__newp + __pos + __len2, __p + __len1, __how_much);
+	      _S_copy(this->_M_data(), __newp, __new_size);
+	      this->_M_get_allocator().deallocate(__newp, __new_size);
+	    }
+	  else
+#endif
+	  if (_M_disjunct(__s))
+	    {
+	      if (__how_much && __len1 != __len2)
+		this->_S_move(__p + __len2, __p + __len1, __how_much);
+	      if (__len2)
+		this->_S_copy(__p, __s, __len2);
+	    }
+	  else
+	    {
+	      // Work in-place.
+	      if (__len2 && __len2 <= __len1)
+		this->_S_move(__p, __s, __len2);
+	      if (__how_much && __len1 != __len2)
+		this->_S_move(__p + __len2, __p + __len1, __how_much);
+	      if (__len2 > __len1)
+		{
+		  if (__s + __len2 <= __p + __len1)
+		    this->_S_move(__p, __s, __len2);
+		  else if (__s >= __p + __len1)
+		    {
+		      // Hint to middle end that __p and __s overlap
+		      // (PR 98465).
+		      const size_type __poff = (__s - __p) + (__len2 - __len1);
+		      this->_S_copy(__p, __p + __poff, __len2);
+		    }
+		  else
+		    {
+		      const size_type __nleft = (__p + __len1) - __s;
+		      this->_S_move(__p, __s, __nleft);
+		      this->_S_copy(__p + __nleft, __p + __len2,
+				    __len2 - __nleft);
+		    }
+		}
+	    }
+	}
+      else
+	this->_M_mutate(__pos, __len1, __s, __len2);
+
+      this->_M_set_length(__new_size);
+      return *this;
+    }
+
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    _GLIBCXX20_CONSTEXPR
+    typename basic_string<_CharT, _Traits, _Alloc>::size_type
+    basic_string<_CharT, _Traits, _Alloc>::
+    copy(_CharT* __s, size_type __n, size_type __pos) const
+    {
+      _M_check(__pos, "basic_string::copy");
+      __n = _M_limit(__pos, __n);
+      __glibcxx_requires_string_len(__s, __n);
+      if (__n)
+	_S_copy(__s, _M_data() + __pos, __n);
+      // 21.3.5.7 par 3: do not append null.  (good.)
+      return __n;
+    }
+
+#if __cplusplus > 202002L
+  template<typename _CharT, typename _Traits, typename _Alloc>
+  template<typename _Operation>
+    constexpr void
+    basic_string<_CharT, _Traits, _Alloc>::
+    resize_and_overwrite(size_type __n, _Operation __op)
+    {
+      const size_type __capacity = capacity();
+      _CharT* __p;
+      if (__n > __capacity)
+	{
+	  __p = _M_create(__n, __capacity);
+	  this->_S_copy(__p, _M_data(), length()); // exclude trailing null
+#if __cpp_lib_is_constant_evaluated
+	  if (std::is_constant_evaluated())
+	    traits_type::assign(__p + length(), __n - length(), _CharT());
+#endif
+	  _M_dispose();
+	  _M_data(__p);
+	  _M_capacity(__n);
+	}
+      else
+	__p = _M_data();
+      struct _Terminator {
+	constexpr ~_Terminator() { _M_this->_M_set_length(_M_r); }
+	basic_string* _M_this;
+	size_type _M_r;
+      };
+      _Terminator __term{this};
+      const size_type __n2 [[maybe_unused]] = __n;
+      __term._M_r = std::move(__op)(__p, __n);
+      _GLIBCXX_DEBUG_ASSERT(__term._M_r >= 0 && __term._M_r <= __n2);
+    }
+#endif // C++23
+
+#endif  // _GLIBCXX_USE_CXX11_ABI
+   
+#if __cpp_lib_constexpr_string >= 201907L
+# define _GLIBCXX_STRING_CONSTEXPR constexpr
+#else
+# define _GLIBCXX_STRING_CONSTEXPR
+#endif
+
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    _GLIBCXX20_CONSTEXPR
+    basic_string<_CharT, _Traits, _Alloc>
+    operator+(const _CharT* __lhs,
+	      const basic_string<_CharT, _Traits, _Alloc>& __rhs)
+    {
+      __glibcxx_requires_string(__lhs);
+      typedef basic_string<_CharT, _Traits, _Alloc> __string_type;
+      typedef typename __string_type::size_type	  __size_type;
+      typedef typename __gnu_cxx::__alloc_traits<_Alloc>::template
+	rebind<_CharT>::other _Char_alloc_type;
+      typedef __gnu_cxx::__alloc_traits<_Char_alloc_type> _Alloc_traits;
+      const __size_type __len = _Traits::length(__lhs);
+      __string_type __str(_Alloc_traits::_S_select_on_copy(
+          __rhs.get_allocator()));
+      __str.reserve(__len + __rhs.size());
+      __str.append(__lhs, __len);
+      __str.append(__rhs);
+      return __str;
+    }
+
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    _GLIBCXX20_CONSTEXPR
+    basic_string<_CharT, _Traits, _Alloc>
+    operator+(_CharT __lhs, const basic_string<_CharT, _Traits, _Alloc>& __rhs)
+    {
+      typedef basic_string<_CharT, _Traits, _Alloc> __string_type;
+      typedef typename __string_type::size_type	  __size_type;
+      typedef typename __gnu_cxx::__alloc_traits<_Alloc>::template
+	rebind<_CharT>::other _Char_alloc_type;
+      typedef __gnu_cxx::__alloc_traits<_Char_alloc_type> _Alloc_traits;
+      __string_type __str(_Alloc_traits::_S_select_on_copy(
+          __rhs.get_allocator()));
+      const __size_type __len = __rhs.size();
+      __str.reserve(__len + 1);
+      __str.append(__size_type(1), __lhs);
+      __str.append(__rhs);
+      return __str;
+    }
+
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    _GLIBCXX_STRING_CONSTEXPR
+    typename basic_string<_CharT, _Traits, _Alloc>::size_type
+    basic_string<_CharT, _Traits, _Alloc>::
+    find(const _CharT* __s, size_type __pos, size_type __n) const
+    _GLIBCXX_NOEXCEPT
+    {
+      __glibcxx_requires_string_len(__s, __n);
+      const size_type __size = this->size();
+
+      if (__n == 0)
+	return __pos <= __size ? __pos : npos;
+      if (__pos >= __size)
+	return npos;
+
+      const _CharT __elem0 = __s[0];
+      const _CharT* const __data = data();
+      const _CharT* __first = __data + __pos;
+      const _CharT* const __last = __data + __size;
+      size_type __len = __size - __pos;
+
+      while (__len >= __n)
+	{
+	  // Find the first occurrence of __elem0:
+	  __first = traits_type::find(__first, __len - __n + 1, __elem0);
+	  if (!__first)
+	    return npos;
+	  // Compare the full strings from the first occurrence of __elem0.
+	  // We already know that __first[0] == __s[0] but compare them again
+	  // anyway because __s is probably aligned, which helps memcmp.
+	  if (traits_type::compare(__first, __s, __n) == 0)
+	    return __first - __data;
+	  __len = __last - ++__first;
+	}
+      return npos;
+    }
+
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    _GLIBCXX_STRING_CONSTEXPR
+    typename basic_string<_CharT, _Traits, _Alloc>::size_type
+    basic_string<_CharT, _Traits, _Alloc>::
+    find(_CharT __c, size_type __pos) const _GLIBCXX_NOEXCEPT
+    {
+      size_type __ret = npos;
+      const size_type __size = this->size();
+      if (__pos < __size)
+	{
+	  const _CharT* __data = _M_data();
+	  const size_type __n = __size - __pos;
+	  const _CharT* __p = traits_type::find(__data + __pos, __n, __c);
+	  if (__p)
+	    __ret = __p - __data;
+	}
+      return __ret;
+    }
+
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    _GLIBCXX_STRING_CONSTEXPR
+    typename basic_string<_CharT, _Traits, _Alloc>::size_type
+    basic_string<_CharT, _Traits, _Alloc>::
+    rfind(const _CharT* __s, size_type __pos, size_type __n) const
+    _GLIBCXX_NOEXCEPT
+    {
+      __glibcxx_requires_string_len(__s, __n);
+      const size_type __size = this->size();
+      if (__n <= __size)
+	{
+	  __pos = std::min(size_type(__size - __n), __pos);
+	  const _CharT* __data = _M_data();
+	  do
+	    {
+	      if (traits_type::compare(__data + __pos, __s, __n) == 0)
+		return __pos;
+	    }
+	  while (__pos-- > 0);
+	}
+      return npos;
+    }
+
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    _GLIBCXX_STRING_CONSTEXPR
+    typename basic_string<_CharT, _Traits, _Alloc>::size_type
+    basic_string<_CharT, _Traits, _Alloc>::
+    rfind(_CharT __c, size_type __pos) const _GLIBCXX_NOEXCEPT
+    {
+      size_type __size = this->size();
+      if (__size)
+	{
+	  if (--__size > __pos)
+	    __size = __pos;
+	  for (++__size; __size-- > 0; )
+	    if (traits_type::eq(_M_data()[__size], __c))
+	      return __size;
+	}
+      return npos;
+    }
+
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    _GLIBCXX_STRING_CONSTEXPR
+    typename basic_string<_CharT, _Traits, _Alloc>::size_type
+    basic_string<_CharT, _Traits, _Alloc>::
+    find_first_of(const _CharT* __s, size_type __pos, size_type __n) const
+    _GLIBCXX_NOEXCEPT
+    {
+      __glibcxx_requires_string_len(__s, __n);
+      for (; __n && __pos < this->size(); ++__pos)
+	{
+	  const _CharT* __p = traits_type::find(__s, __n, _M_data()[__pos]);
+	  if (__p)
+	    return __pos;
+	}
+      return npos;
+    }
+
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    _GLIBCXX_STRING_CONSTEXPR
+    typename basic_string<_CharT, _Traits, _Alloc>::size_type
+    basic_string<_CharT, _Traits, _Alloc>::
+    find_last_of(const _CharT* __s, size_type __pos, size_type __n) const
+    _GLIBCXX_NOEXCEPT
+    {
+      __glibcxx_requires_string_len(__s, __n);
+      size_type __size = this->size();
+      if (__size && __n)
+	{
+	  if (--__size > __pos)
+	    __size = __pos;
+	  do
+	    {
+	      if (traits_type::find(__s, __n, _M_data()[__size]))
+		return __size;
+	    }
+	  while (__size-- != 0);
+	}
+      return npos;
+    }
+
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    _GLIBCXX_STRING_CONSTEXPR
+    typename basic_string<_CharT, _Traits, _Alloc>::size_type
+    basic_string<_CharT, _Traits, _Alloc>::
+    find_first_not_of(const _CharT* __s, size_type __pos, size_type __n) const
+    _GLIBCXX_NOEXCEPT
+    {
+      __glibcxx_requires_string_len(__s, __n);
+      for (; __pos < this->size(); ++__pos)
+	if (!traits_type::find(__s, __n, _M_data()[__pos]))
+	  return __pos;
+      return npos;
+    }
+
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    _GLIBCXX_STRING_CONSTEXPR
+    typename basic_string<_CharT, _Traits, _Alloc>::size_type
+    basic_string<_CharT, _Traits, _Alloc>::
+    find_first_not_of(_CharT __c, size_type __pos) const _GLIBCXX_NOEXCEPT
+    {
+      for (; __pos < this->size(); ++__pos)
+	if (!traits_type::eq(_M_data()[__pos], __c))
+	  return __pos;
+      return npos;
+    }
+
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    _GLIBCXX_STRING_CONSTEXPR
+    typename basic_string<_CharT, _Traits, _Alloc>::size_type
+    basic_string<_CharT, _Traits, _Alloc>::
+    find_last_not_of(const _CharT* __s, size_type __pos, size_type __n) const
+    _GLIBCXX_NOEXCEPT
+    {
+      __glibcxx_requires_string_len(__s, __n);
+      size_type __size = this->size();
+      if (__size)
+	{
+	  if (--__size > __pos)
+	    __size = __pos;
+	  do
+	    {
+	      if (!traits_type::find(__s, __n, _M_data()[__size]))
+		return __size;
+	    }
+	  while (__size--);
+	}
+      return npos;
+    }
+
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    _GLIBCXX_STRING_CONSTEXPR
+    typename basic_string<_CharT, _Traits, _Alloc>::size_type
+    basic_string<_CharT, _Traits, _Alloc>::
+    find_last_not_of(_CharT __c, size_type __pos) const _GLIBCXX_NOEXCEPT
+    {
+      size_type __size = this->size();
+      if (__size)
+	{
+	  if (--__size > __pos)
+	    __size = __pos;
+	  do
+	    {
+	      if (!traits_type::eq(_M_data()[__size], __c))
+		return __size;
+	    }
+	  while (__size--);
+	}
+      return npos;
+    }
+
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    _GLIBCXX_STRING_CONSTEXPR
+    int
+    basic_string<_CharT, _Traits, _Alloc>::
+    compare(size_type __pos, size_type __n, const basic_string& __str) const
+    {
+      _M_check(__pos, "basic_string::compare");
+      __n = _M_limit(__pos, __n);
+      const size_type __osize = __str.size();
+      const size_type __len = std::min(__n, __osize);
+      int __r = traits_type::compare(_M_data() + __pos, __str.data(), __len);
+      if (!__r)
+	__r = _S_compare(__n, __osize);
+      return __r;
+    }
+
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    _GLIBCXX_STRING_CONSTEXPR
+    int
+    basic_string<_CharT, _Traits, _Alloc>::
+    compare(size_type __pos1, size_type __n1, const basic_string& __str,
+	    size_type __pos2, size_type __n2) const
+    {
+      _M_check(__pos1, "basic_string::compare");
+      __str._M_check(__pos2, "basic_string::compare");
+      __n1 = _M_limit(__pos1, __n1);
+      __n2 = __str._M_limit(__pos2, __n2);
+      const size_type __len = std::min(__n1, __n2);
+      int __r = traits_type::compare(_M_data() + __pos1,
+				     __str.data() + __pos2, __len);
+      if (!__r)
+	__r = _S_compare(__n1, __n2);
+      return __r;
+    }
+
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    _GLIBCXX_STRING_CONSTEXPR
+    int
+    basic_string<_CharT, _Traits, _Alloc>::
+    compare(const _CharT* __s) const _GLIBCXX_NOEXCEPT
+    {
+      __glibcxx_requires_string(__s);
+      const size_type __size = this->size();
+      const size_type __osize = traits_type::length(__s);
+      const size_type __len = std::min(__size, __osize);
+      int __r = traits_type::compare(_M_data(), __s, __len);
+      if (!__r)
+	__r = _S_compare(__size, __osize);
+      return __r;
+    }
+
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    _GLIBCXX_STRING_CONSTEXPR
+    int
+    basic_string <_CharT, _Traits, _Alloc>::
+    compare(size_type __pos, size_type __n1, const _CharT* __s) const
+    {
+      __glibcxx_requires_string(__s);
+      _M_check(__pos, "basic_string::compare");
+      __n1 = _M_limit(__pos, __n1);
+      const size_type __osize = traits_type::length(__s);
+      const size_type __len = std::min(__n1, __osize);
+      int __r = traits_type::compare(_M_data() + __pos, __s, __len);
+      if (!__r)
+	__r = _S_compare(__n1, __osize);
+      return __r;
+    }
+
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    _GLIBCXX_STRING_CONSTEXPR
+    int
+    basic_string <_CharT, _Traits, _Alloc>::
+    compare(size_type __pos, size_type __n1, const _CharT* __s,
+	    size_type __n2) const
+    {
+      __glibcxx_requires_string_len(__s, __n2);
+      _M_check(__pos, "basic_string::compare");
+      __n1 = _M_limit(__pos, __n1);
+      const size_type __len = std::min(__n1, __n2);
+      int __r = traits_type::compare(_M_data() + __pos, __s, __len);
+      if (!__r)
+	__r = _S_compare(__n1, __n2);
+      return __r;
+    }
+
+#undef _GLIBCXX_STRING_CONSTEXPR
+
+  // 21.3.7.9 basic_string::getline and operators
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    basic_istream<_CharT, _Traits>&
+    operator>>(basic_istream<_CharT, _Traits>& __in,
+	       basic_string<_CharT, _Traits, _Alloc>& __str)
+    {
+      typedef basic_istream<_CharT, _Traits>		__istream_type;
+      typedef basic_string<_CharT, _Traits, _Alloc>	__string_type;
+      typedef typename __istream_type::ios_base         __ios_base;
+      typedef typename __istream_type::int_type		__int_type;
+      typedef typename __string_type::size_type		__size_type;
+      typedef ctype<_CharT>				__ctype_type;
+      typedef typename __ctype_type::ctype_base         __ctype_base;
+
+      __size_type __extracted = 0;
+      typename __ios_base::iostate __err = __ios_base::goodbit;
+      typename __istream_type::sentry __cerb(__in, false);
+      if (__cerb)
+	{
+	  __try
+	    {
+	      // Avoid reallocation for common case.
+	      __str.erase();
+	      _CharT __buf[128];
+	      __size_type __len = 0;	      
+	      const streamsize __w = __in.width();
+	      const __size_type __n = __w > 0 ? static_cast<__size_type>(__w)
+		                              : __str.max_size();
+	      const __ctype_type& __ct = use_facet<__ctype_type>(__in.getloc());
+	      const __int_type __eof = _Traits::eof();
+	      __int_type __c = __in.rdbuf()->sgetc();
+
+	      while (__extracted < __n
+		     && !_Traits::eq_int_type(__c, __eof)
+		     && !__ct.is(__ctype_base::space,
+				 _Traits::to_char_type(__c)))
+		{
+		  if (__len == sizeof(__buf) / sizeof(_CharT))
+		    {
+		      __str.append(__buf, sizeof(__buf) / sizeof(_CharT));
+		      __len = 0;
+		    }
+		  __buf[__len++] = _Traits::to_char_type(__c);
+		  ++__extracted;
+		  __c = __in.rdbuf()->snextc();
+		}
+	      __str.append(__buf, __len);
+
+	      if (__extracted < __n && _Traits::eq_int_type(__c, __eof))
+		__err |= __ios_base::eofbit;
+	      __in.width(0);
+	    }
+	  __catch(__cxxabiv1::__forced_unwind&)
+	    {
+	      __in._M_setstate(__ios_base::badbit);
+	      __throw_exception_again;
+	    }
+	  __catch(...)
+	    {
+	      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+	      // 91. Description of operator>> and getline() for string<>
+	      // might cause endless loop
+	      __in._M_setstate(__ios_base::badbit);
+	    }
+	}
+      // 211.  operator>>(istream&, string&) doesn't set failbit
+      if (!__extracted)
+	__err |= __ios_base::failbit;
+      if (__err)
+	__in.setstate(__err);
+      return __in;
+    }
+
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    basic_istream<_CharT, _Traits>&
+    getline(basic_istream<_CharT, _Traits>& __in,
+	    basic_string<_CharT, _Traits, _Alloc>& __str, _CharT __delim)
+    {
+      typedef basic_istream<_CharT, _Traits>		__istream_type;
+      typedef basic_string<_CharT, _Traits, _Alloc>	__string_type;
+      typedef typename __istream_type::ios_base         __ios_base;
+      typedef typename __istream_type::int_type		__int_type;
+      typedef typename __string_type::size_type		__size_type;
+
+      __size_type __extracted = 0;
+      const __size_type __n = __str.max_size();
+      typename __ios_base::iostate __err = __ios_base::goodbit;
+      typename __istream_type::sentry __cerb(__in, true);
+      if (__cerb)
+	{
+	  __try
+	    {
+	      __str.erase();
+	      const __int_type __idelim = _Traits::to_int_type(__delim);
+	      const __int_type __eof = _Traits::eof();
+	      __int_type __c = __in.rdbuf()->sgetc();
+
+	      while (__extracted < __n
+		     && !_Traits::eq_int_type(__c, __eof)
+		     && !_Traits::eq_int_type(__c, __idelim))
+		{
+		  __str += _Traits::to_char_type(__c);
+		  ++__extracted;
+		  __c = __in.rdbuf()->snextc();
+		}
+
+	      if (_Traits::eq_int_type(__c, __eof))
+		__err |= __ios_base::eofbit;
+	      else if (_Traits::eq_int_type(__c, __idelim))
+		{
+		  ++__extracted;		  
+		  __in.rdbuf()->sbumpc();
+		}
+	      else
+		__err |= __ios_base::failbit;
+	    }
+	  __catch(__cxxabiv1::__forced_unwind&)
+	    {
+	      __in._M_setstate(__ios_base::badbit);
+	      __throw_exception_again;
+	    }
+	  __catch(...)
+	    {
+	      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+	      // 91. Description of operator>> and getline() for string<>
+	      // might cause endless loop
+	      __in._M_setstate(__ios_base::badbit);
+	    }
+	}
+      if (!__extracted)
+	__err |= __ios_base::failbit;
+      if (__err)
+	__in.setstate(__err);
+      return __in;
+    }
+
+  // Inhibit implicit instantiations for required instantiations,
+  // which are defined via explicit instantiations elsewhere.
+#if _GLIBCXX_EXTERN_TEMPLATE
+  // The explicit instantiation definitions in src/c++11/string-inst.cc and
+  // src/c++17/string-inst.cc only instantiate the members required for C++17
+  // and earlier standards (so not C++20's starts_with and ends_with).
+  // Suppress the explicit instantiation declarations for C++20, so C++20
+  // code will implicitly instantiate std::string and std::wstring as needed.
+# if __cplusplus <= 201703L && _GLIBCXX_EXTERN_TEMPLATE > 0
+  extern template class basic_string<char>;
+# elif ! _GLIBCXX_USE_CXX11_ABI
+  // Still need to prevent implicit instantiation of the COW empty rep,
+  // to ensure the definition in libstdc++.so is unique (PR 86138).
+  extern template basic_string<char>::size_type
+    basic_string<char>::_Rep::_S_empty_rep_storage[];
+# endif
+
+  extern template
+    basic_istream<char>&
+    operator>>(basic_istream<char>&, string&);
+  extern template
+    basic_ostream<char>&
+    operator<<(basic_ostream<char>&, const string&);
+  extern template
+    basic_istream<char>&
+    getline(basic_istream<char>&, string&, char);
+  extern template
+    basic_istream<char>&
+    getline(basic_istream<char>&, string&);
+
+#ifdef _GLIBCXX_USE_WCHAR_T
+# if __cplusplus <= 201703L && _GLIBCXX_EXTERN_TEMPLATE > 0
+  extern template class basic_string<wchar_t>;
+# elif ! _GLIBCXX_USE_CXX11_ABI
+  extern template basic_string<wchar_t>::size_type
+    basic_string<wchar_t>::_Rep::_S_empty_rep_storage[];
+# endif
+
+  extern template
+    basic_istream<wchar_t>&
+    operator>>(basic_istream<wchar_t>&, wstring&);
+  extern template
+    basic_ostream<wchar_t>&
+    operator<<(basic_ostream<wchar_t>&, const wstring&);
+  extern template
+    basic_istream<wchar_t>&
+    getline(basic_istream<wchar_t>&, wstring&, wchar_t);
+  extern template
+    basic_istream<wchar_t>&
+    getline(basic_istream<wchar_t>&, wstring&);
+#endif // _GLIBCXX_USE_WCHAR_T
+#endif // _GLIBCXX_EXTERN_TEMPLATE
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif
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@@ -0,0 +1,1005 @@
+// Character Traits for use by standard string and iostream -*- C++ -*-
+
+// Copyright (C) 1997-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/char_traits.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{string}
+ */
+
+//
+// ISO C++ 14882: 21  Strings library
+//
+
+#ifndef _CHAR_TRAITS_H
+#define _CHAR_TRAITS_H 1
+
+#pragma GCC system_header
+
+#include <bits/postypes.h>      // For streampos
+#include <cwchar>               // For WEOF, wmemmove, wmemset, etc.
+#if __cplusplus >= 201103L
+# include <type_traits>
+#endif
+#if __cplusplus >= 202002L
+# include <compare>
+# include <bits/stl_construct.h>
+#endif
+
+#ifndef _GLIBCXX_ALWAYS_INLINE
+# define _GLIBCXX_ALWAYS_INLINE inline __attribute__((__always_inline__))
+#endif
+
+namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wstringop-overflow"
+#pragma GCC diagnostic ignored "-Wstringop-overread"
+#pragma GCC diagnostic ignored "-Warray-bounds"
+
+  /**
+   *  @brief  Mapping from character type to associated types.
+   *
+   *  @note This is an implementation class for the generic version
+   *  of char_traits.  It defines int_type, off_type, pos_type, and
+   *  state_type.  By default these are unsigned long, streamoff,
+   *  streampos, and mbstate_t.  Users who need a different set of
+   *  types, but who don't need to change the definitions of any function
+   *  defined in char_traits, can specialize __gnu_cxx::_Char_types
+   *  while leaving __gnu_cxx::char_traits alone. */
+  template<typename _CharT>
+    struct _Char_types
+    {
+      typedef unsigned long   int_type;
+      typedef std::streampos  pos_type;
+      typedef std::streamoff  off_type;
+      typedef std::mbstate_t  state_type;
+    };
+
+
+  /**
+   *  @brief  Base class used to implement std::char_traits.
+   *
+   *  @note For any given actual character type, this definition is
+   *  probably wrong.  (Most of the member functions are likely to be
+   *  right, but the int_type and state_type typedefs, and the eof()
+   *  member function, are likely to be wrong.)  The reason this class
+   *  exists is so users can specialize it.  Classes in namespace std
+   *  may not be specialized for fundamental types, but classes in
+   *  namespace __gnu_cxx may be.
+   *
+   *  See https://gcc.gnu.org/onlinedocs/libstdc++/manual/strings.html#strings.string.character_types
+   *  for advice on how to make use of this class for @a unusual character
+   *  types. Also, check out include/ext/pod_char_traits.h.  
+   */
+  template<typename _CharT>
+    struct char_traits
+    {
+      typedef _CharT                                    char_type;
+      typedef typename _Char_types<_CharT>::int_type    int_type;
+      typedef typename _Char_types<_CharT>::pos_type    pos_type;
+      typedef typename _Char_types<_CharT>::off_type    off_type;
+      typedef typename _Char_types<_CharT>::state_type  state_type;
+#if __cpp_lib_three_way_comparison
+      using comparison_category = std::strong_ordering;
+#endif
+
+      static _GLIBCXX14_CONSTEXPR void
+      assign(char_type& __c1, const char_type& __c2)
+      {
+#if __cpp_constexpr_dynamic_alloc
+	if (std::__is_constant_evaluated())
+	  std::construct_at(__builtin_addressof(__c1), __c2);
+	else
+#endif
+	__c1 = __c2;
+      }
+
+      static _GLIBCXX_CONSTEXPR bool
+      eq(const char_type& __c1, const char_type& __c2)
+      { return __c1 == __c2; }
+
+      static _GLIBCXX_CONSTEXPR bool
+      lt(const char_type& __c1, const char_type& __c2)
+      { return __c1 < __c2; }
+
+      static _GLIBCXX14_CONSTEXPR int
+      compare(const char_type* __s1, const char_type* __s2, std::size_t __n);
+
+      static _GLIBCXX14_CONSTEXPR std::size_t
+      length(const char_type* __s);
+
+      static _GLIBCXX14_CONSTEXPR const char_type*
+      find(const char_type* __s, std::size_t __n, const char_type& __a);
+
+      static _GLIBCXX20_CONSTEXPR char_type*
+      move(char_type* __s1, const char_type* __s2, std::size_t __n);
+
+      static _GLIBCXX20_CONSTEXPR char_type*
+      copy(char_type* __s1, const char_type* __s2, std::size_t __n);
+
+      static _GLIBCXX20_CONSTEXPR char_type*
+      assign(char_type* __s, std::size_t __n, char_type __a);
+
+      static _GLIBCXX_CONSTEXPR char_type
+      to_char_type(const int_type& __c)
+      { return static_cast<char_type>(__c); }
+
+      static _GLIBCXX_CONSTEXPR int_type
+      to_int_type(const char_type& __c)
+      { return static_cast<int_type>(__c); }
+
+      static _GLIBCXX_CONSTEXPR bool
+      eq_int_type(const int_type& __c1, const int_type& __c2)
+      { return __c1 == __c2; }
+
+      static _GLIBCXX_CONSTEXPR int_type
+      eof()
+      { return static_cast<int_type>(_GLIBCXX_STDIO_EOF); }
+
+      static _GLIBCXX_CONSTEXPR int_type
+      not_eof(const int_type& __c)
+      { return !eq_int_type(__c, eof()) ? __c : to_int_type(char_type()); }
+    };
+
+  template<typename _CharT>
+    _GLIBCXX14_CONSTEXPR int
+    char_traits<_CharT>::
+    compare(const char_type* __s1, const char_type* __s2, std::size_t __n)
+    {
+      for (std::size_t __i = 0; __i < __n; ++__i)
+	if (lt(__s1[__i], __s2[__i]))
+	  return -1;
+	else if (lt(__s2[__i], __s1[__i]))
+	  return 1;
+      return 0;
+    }
+
+  template<typename _CharT>
+    _GLIBCXX14_CONSTEXPR std::size_t
+    char_traits<_CharT>::
+    length(const char_type* __p)
+    {
+      std::size_t __i = 0;
+      while (!eq(__p[__i], char_type()))
+        ++__i;
+      return __i;
+    }
+
+  template<typename _CharT>
+    _GLIBCXX14_CONSTEXPR const typename char_traits<_CharT>::char_type*
+    char_traits<_CharT>::
+    find(const char_type* __s, std::size_t __n, const char_type& __a)
+    {
+      for (std::size_t __i = 0; __i < __n; ++__i)
+        if (eq(__s[__i], __a))
+          return __s + __i;
+      return 0;
+    }
+
+  template<typename _CharT>
+    _GLIBCXX20_CONSTEXPR
+    typename char_traits<_CharT>::char_type*
+    char_traits<_CharT>::
+    move(char_type* __s1, const char_type* __s2, std::size_t __n)
+    {
+      if (__n == 0)
+	return __s1;
+#if __cplusplus >= 202002L
+      if (std::__is_constant_evaluated())
+	{
+	  if (__s1 == __s2) // unlikely, but saves a lot of work
+	    return __s1;
+#if __cpp_constexpr_dynamic_alloc
+	  // The overlap detection below fails due to PR c++/89074,
+	  // so use a temporary buffer instead.
+	  char_type* __tmp = new char_type[__n];
+	  copy(__tmp, __s2, __n);
+	  copy(__s1, __tmp, __n);
+	  delete[] __tmp;
+#else
+	  const auto __end = __s2 + __n - 1;
+	  bool __overlap = false;
+	  for (std::size_t __i = 0; __i < __n - 1; ++__i)
+	    {
+	      if (__s1 + __i == __end)
+		{
+		  __overlap = true;
+		  break;
+		}
+	    }
+	  if (__overlap)
+	    {
+	      do
+		{
+		  --__n;
+		  assign(__s1[__n], __s2[__n]);
+		}
+	      while (__n > 0);
+	    }
+	  else
+	    copy(__s1, __s2, __n);
+#endif
+	  return __s1;
+	}
+#endif
+      __builtin_memmove(__s1, __s2, __n * sizeof(char_type));
+      return __s1;
+    }
+
+  template<typename _CharT>
+    _GLIBCXX20_CONSTEXPR
+    typename char_traits<_CharT>::char_type*
+    char_traits<_CharT>::
+    copy(char_type* __s1, const char_type* __s2, std::size_t __n)
+    {
+#if __cplusplus >= 202002L
+      if (std::__is_constant_evaluated())
+	{
+	  for (std::size_t __i = 0; __i < __n; ++__i)
+	    std::construct_at(__s1 + __i, __s2[__i]);
+	  return __s1;
+	}
+#endif
+
+      __builtin_memcpy(__s1, __s2, __n * sizeof(char_type));
+      return __s1;
+    }
+
+  template<typename _CharT>
+    _GLIBCXX20_CONSTEXPR
+    typename char_traits<_CharT>::char_type*
+    char_traits<_CharT>::
+    assign(char_type* __s, std::size_t __n, char_type __a)
+    {
+#if __cplusplus >= 202002L
+      if (std::__is_constant_evaluated())
+	{
+	  for (std::size_t __i = 0; __i < __n; ++__i)
+	    std::construct_at(__s + __i, __a);
+	  return __s;
+	}
+#endif
+
+      if _GLIBCXX17_CONSTEXPR (sizeof(_CharT) == 1 && __is_trivial(_CharT))
+	{
+	  unsigned char __c;
+	  __builtin_memcpy(&__c, __builtin_addressof(__a), 1);
+	  __builtin_memset(__s, __c, __n);
+	}
+      else
+	{
+	  for (std::size_t __i = 0; __i < __n; ++__i)
+	    __s[__i] = __a;
+	}
+      return __s;
+    }
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+#ifdef __cpp_lib_is_constant_evaluated
+// Unofficial macro indicating P1032R1 support in C++20
+# define __cpp_lib_constexpr_char_traits 201811L
+#elif __cplusplus >= 201703L && _GLIBCXX_HAVE_IS_CONSTANT_EVALUATED
+// Unofficial macro indicating P0426R1 support in C++17
+# define __cpp_lib_constexpr_char_traits 201611L
+#endif
+
+  // 21.1
+  /**
+   *  @brief  Basis for explicit traits specializations.
+   *
+   *  @note  For any given actual character type, this definition is
+   *  probably wrong.  Since this is just a thin wrapper around
+   *  __gnu_cxx::char_traits, it is possible to achieve a more
+   *  appropriate definition by specializing __gnu_cxx::char_traits.
+   *
+   *  See https://gcc.gnu.org/onlinedocs/libstdc++/manual/strings.html#strings.string.character_types
+   *  for advice on how to make use of this class for @a unusual character
+   *  types. Also, check out include/ext/pod_char_traits.h.
+  */
+  template<typename _CharT>
+    struct char_traits : public __gnu_cxx::char_traits<_CharT>
+    { };
+
+
+  /// 21.1.3.1  char_traits specializations
+  template<>
+    struct char_traits<char>
+    {
+      typedef char              char_type;
+      typedef int               int_type;
+      typedef streampos         pos_type;
+      typedef streamoff         off_type;
+      typedef mbstate_t         state_type;
+#if __cpp_lib_three_way_comparison
+      using comparison_category = strong_ordering;
+#endif
+
+      static _GLIBCXX17_CONSTEXPR void
+      assign(char_type& __c1, const char_type& __c2) _GLIBCXX_NOEXCEPT
+      {
+#if __cpp_constexpr_dynamic_alloc
+	if (std::__is_constant_evaluated())
+	  std::construct_at(__builtin_addressof(__c1), __c2);
+	else
+#endif
+	__c1 = __c2;
+      }
+
+      static _GLIBCXX_CONSTEXPR bool
+      eq(const char_type& __c1, const char_type& __c2) _GLIBCXX_NOEXCEPT
+      { return __c1 == __c2; }
+
+      static _GLIBCXX_CONSTEXPR bool
+      lt(const char_type& __c1, const char_type& __c2) _GLIBCXX_NOEXCEPT
+      {
+	// LWG 467.
+	return (static_cast<unsigned char>(__c1)
+		< static_cast<unsigned char>(__c2));
+      }
+
+      static _GLIBCXX17_CONSTEXPR int
+      compare(const char_type* __s1, const char_type* __s2, size_t __n)
+      {
+	if (__n == 0)
+	  return 0;
+#if __cplusplus >= 201703L
+	if (std::__is_constant_evaluated())
+	  {
+	    for (size_t __i = 0; __i < __n; ++__i)
+	      if (lt(__s1[__i], __s2[__i]))
+		return -1;
+	      else if (lt(__s2[__i], __s1[__i]))
+		return 1;
+	    return 0;
+	  }
+#endif
+	return __builtin_memcmp(__s1, __s2, __n);
+      }
+
+      static _GLIBCXX17_CONSTEXPR size_t
+      length(const char_type* __s)
+      {
+#if __cplusplus >= 201703L
+	if (std::__is_constant_evaluated())
+	  return __gnu_cxx::char_traits<char_type>::length(__s);
+#endif
+	return __builtin_strlen(__s);
+      }
+
+      static _GLIBCXX17_CONSTEXPR const char_type*
+      find(const char_type* __s, size_t __n, const char_type& __a)
+      {
+	if (__n == 0)
+	  return 0;
+#if __cplusplus >= 201703L
+	if (std::__is_constant_evaluated())
+	  return __gnu_cxx::char_traits<char_type>::find(__s, __n, __a);
+#endif
+	return static_cast<const char_type*>(__builtin_memchr(__s, __a, __n));
+      }
+
+      static _GLIBCXX20_CONSTEXPR char_type*
+      move(char_type* __s1, const char_type* __s2, size_t __n)
+      {
+	if (__n == 0)
+	  return __s1;
+#if __cplusplus >= 202002L
+	if (std::__is_constant_evaluated())
+	  return __gnu_cxx::char_traits<char_type>::move(__s1, __s2, __n);
+#endif
+	return static_cast<char_type*>(__builtin_memmove(__s1, __s2, __n));
+      }
+
+      static _GLIBCXX20_CONSTEXPR char_type*
+      copy(char_type* __s1, const char_type* __s2, size_t __n)
+      {
+	if (__n == 0)
+	  return __s1;
+#if __cplusplus >= 202002L
+	if (std::__is_constant_evaluated())
+	  return __gnu_cxx::char_traits<char_type>::copy(__s1, __s2, __n);
+#endif
+	return static_cast<char_type*>(__builtin_memcpy(__s1, __s2, __n));
+      }
+
+      static _GLIBCXX20_CONSTEXPR char_type*
+      assign(char_type* __s, size_t __n, char_type __a)
+      {
+	if (__n == 0)
+	  return __s;
+#if __cplusplus >= 202002L
+	if (std::__is_constant_evaluated())
+	  return __gnu_cxx::char_traits<char_type>::assign(__s, __n, __a);
+#endif
+	return static_cast<char_type*>(__builtin_memset(__s, __a, __n));
+      }
+
+      static _GLIBCXX_CONSTEXPR char_type
+      to_char_type(const int_type& __c) _GLIBCXX_NOEXCEPT
+      { return static_cast<char_type>(__c); }
+
+      // To keep both the byte 0xff and the eof symbol 0xffffffff
+      // from ending up as 0xffffffff.
+      static _GLIBCXX_CONSTEXPR int_type
+      to_int_type(const char_type& __c) _GLIBCXX_NOEXCEPT
+      { return static_cast<int_type>(static_cast<unsigned char>(__c)); }
+
+      static _GLIBCXX_CONSTEXPR bool
+      eq_int_type(const int_type& __c1, const int_type& __c2) _GLIBCXX_NOEXCEPT
+      { return __c1 == __c2; }
+
+      static _GLIBCXX_CONSTEXPR int_type
+      eof() _GLIBCXX_NOEXCEPT
+      { return static_cast<int_type>(_GLIBCXX_STDIO_EOF); }
+
+      static _GLIBCXX_CONSTEXPR int_type
+      not_eof(const int_type& __c) _GLIBCXX_NOEXCEPT
+      { return (__c == eof()) ? 0 : __c; }
+  };
+
+
+#ifdef _GLIBCXX_USE_WCHAR_T
+  /// 21.1.3.2  char_traits specializations
+  template<>
+    struct char_traits<wchar_t>
+    {
+      typedef wchar_t           char_type;
+      typedef wint_t            int_type;
+      typedef streamoff         off_type;
+      typedef wstreampos        pos_type;
+      typedef mbstate_t         state_type;
+#if __cpp_lib_three_way_comparison
+      using comparison_category = strong_ordering;
+#endif
+
+      static _GLIBCXX17_CONSTEXPR void
+      assign(char_type& __c1, const char_type& __c2) _GLIBCXX_NOEXCEPT
+      {
+#if __cpp_constexpr_dynamic_alloc
+	if (std::__is_constant_evaluated())
+	  std::construct_at(__builtin_addressof(__c1), __c2);
+	else
+#endif
+	__c1 = __c2;
+      }
+
+      static _GLIBCXX_CONSTEXPR bool
+      eq(const char_type& __c1, const char_type& __c2) _GLIBCXX_NOEXCEPT
+      { return __c1 == __c2; }
+
+      static _GLIBCXX_CONSTEXPR bool
+      lt(const char_type& __c1, const char_type& __c2) _GLIBCXX_NOEXCEPT
+      { return __c1 < __c2; }
+
+      static _GLIBCXX17_CONSTEXPR int
+      compare(const char_type* __s1, const char_type* __s2, size_t __n)
+      {
+	if (__n == 0)
+	  return 0;
+#if __cplusplus >= 201703L
+	if (std::__is_constant_evaluated())
+	  return __gnu_cxx::char_traits<char_type>::compare(__s1, __s2, __n);
+#endif
+	return wmemcmp(__s1, __s2, __n);
+      }
+
+      static _GLIBCXX17_CONSTEXPR size_t
+      length(const char_type* __s)
+      {
+#if __cplusplus >= 201703L
+	if (std::__is_constant_evaluated())
+	  return __gnu_cxx::char_traits<char_type>::length(__s);
+#endif
+	return wcslen(__s);
+      }
+
+      static _GLIBCXX17_CONSTEXPR const char_type*
+      find(const char_type* __s, size_t __n, const char_type& __a)
+      {
+	if (__n == 0)
+	  return 0;
+#if __cplusplus >= 201703L
+	if (std::__is_constant_evaluated())
+	  return __gnu_cxx::char_traits<char_type>::find(__s, __n, __a);
+#endif
+	return wmemchr(__s, __a, __n);
+      }
+
+      static _GLIBCXX20_CONSTEXPR char_type*
+      move(char_type* __s1, const char_type* __s2, size_t __n)
+      {
+	if (__n == 0)
+	  return __s1;
+#if __cplusplus >= 202002L
+	if (std::__is_constant_evaluated())
+	  return __gnu_cxx::char_traits<char_type>::move(__s1, __s2, __n);
+#endif
+	return wmemmove(__s1, __s2, __n);
+      }
+
+      static _GLIBCXX20_CONSTEXPR char_type*
+      copy(char_type* __s1, const char_type* __s2, size_t __n)
+      {
+	if (__n == 0)
+	  return __s1;
+#if __cplusplus >= 202002L
+	if (std::__is_constant_evaluated())
+	  return __gnu_cxx::char_traits<char_type>::copy(__s1, __s2, __n);
+#endif
+	return wmemcpy(__s1, __s2, __n);
+      }
+
+      static _GLIBCXX20_CONSTEXPR char_type*
+      assign(char_type* __s, size_t __n, char_type __a)
+      {
+	if (__n == 0)
+	  return __s;
+#if __cplusplus >= 202002L
+	if (std::__is_constant_evaluated())
+	  return __gnu_cxx::char_traits<char_type>::assign(__s, __n, __a);
+#endif
+	return wmemset(__s, __a, __n);
+      }
+
+      static _GLIBCXX_CONSTEXPR char_type
+      to_char_type(const int_type& __c) _GLIBCXX_NOEXCEPT
+      { return char_type(__c); }
+
+      static _GLIBCXX_CONSTEXPR int_type
+      to_int_type(const char_type& __c) _GLIBCXX_NOEXCEPT
+      { return int_type(__c); }
+
+      static _GLIBCXX_CONSTEXPR bool
+      eq_int_type(const int_type& __c1, const int_type& __c2) _GLIBCXX_NOEXCEPT
+      { return __c1 == __c2; }
+
+      static _GLIBCXX_CONSTEXPR int_type
+      eof() _GLIBCXX_NOEXCEPT
+      { return static_cast<int_type>(WEOF); }
+
+      static _GLIBCXX_CONSTEXPR int_type
+      not_eof(const int_type& __c) _GLIBCXX_NOEXCEPT
+      { return eq_int_type(__c, eof()) ? 0 : __c; }
+  };
+#else // _GLIBCXX_USE_WCHAR_T
+  template<>
+    struct char_traits<wchar_t> : public __gnu_cxx::char_traits<wchar_t>
+    { };
+#endif //_GLIBCXX_USE_WCHAR_T
+
+#ifdef _GLIBCXX_USE_CHAR8_T
+  template<>
+    struct char_traits<char8_t>
+    {
+      typedef char8_t           char_type;
+      typedef unsigned int      int_type;
+      typedef u8streampos       pos_type;
+      typedef streamoff         off_type;
+      typedef mbstate_t         state_type;
+#if __cpp_lib_three_way_comparison
+      using comparison_category = strong_ordering;
+#endif
+
+      static _GLIBCXX17_CONSTEXPR void
+      assign(char_type& __c1, const char_type& __c2) _GLIBCXX_NOEXCEPT
+      {
+#if __cpp_constexpr_dynamic_alloc
+	if (std::__is_constant_evaluated())
+	  std::construct_at(__builtin_addressof(__c1), __c2);
+	else
+#endif
+	__c1 = __c2;
+      }
+
+      static _GLIBCXX_CONSTEXPR bool
+      eq(const char_type& __c1, const char_type& __c2) _GLIBCXX_NOEXCEPT
+      { return __c1 == __c2; }
+
+      static _GLIBCXX_CONSTEXPR bool
+      lt(const char_type& __c1, const char_type& __c2) _GLIBCXX_NOEXCEPT
+      { return __c1 < __c2; }
+
+      static _GLIBCXX17_CONSTEXPR int
+      compare(const char_type* __s1, const char_type* __s2, size_t __n)
+      {
+	if (__n == 0)
+	  return 0;
+#if __cplusplus >= 201703L
+	if (std::__is_constant_evaluated())
+	  return __gnu_cxx::char_traits<char_type>::compare(__s1, __s2, __n);
+#endif
+	return __builtin_memcmp(__s1, __s2, __n);
+      }
+
+      static _GLIBCXX17_CONSTEXPR size_t
+      length(const char_type* __s)
+      {
+#if __cplusplus >= 201703L
+	if (std::__is_constant_evaluated())
+	  return __gnu_cxx::char_traits<char_type>::length(__s);
+#endif
+	size_t __i = 0;
+	while (!eq(__s[__i], char_type()))
+	  ++__i;
+	return __i;
+      }
+
+      static _GLIBCXX17_CONSTEXPR const char_type*
+      find(const char_type* __s, size_t __n, const char_type& __a)
+      {
+	if (__n == 0)
+	  return 0;
+#if __cplusplus >= 201703L
+	if (std::__is_constant_evaluated())
+	  return __gnu_cxx::char_traits<char_type>::find(__s, __n, __a);
+#endif
+	return static_cast<const char_type*>(__builtin_memchr(__s, __a, __n));
+      }
+
+      static _GLIBCXX20_CONSTEXPR char_type*
+      move(char_type* __s1, const char_type* __s2, size_t __n)
+      {
+	if (__n == 0)
+	  return __s1;
+#if __cplusplus >= 202002L
+	if (std::__is_constant_evaluated())
+	  return __gnu_cxx::char_traits<char_type>::move(__s1, __s2, __n);
+#endif
+	return static_cast<char_type*>(__builtin_memmove(__s1, __s2, __n));
+      }
+
+      static _GLIBCXX20_CONSTEXPR char_type*
+      copy(char_type* __s1, const char_type* __s2, size_t __n)
+      {
+	if (__n == 0)
+	  return __s1;
+#if __cplusplus >= 202002L
+	if (std::__is_constant_evaluated())
+	  return __gnu_cxx::char_traits<char_type>::copy(__s1, __s2, __n);
+#endif
+	return static_cast<char_type*>(__builtin_memcpy(__s1, __s2, __n));
+      }
+
+      static _GLIBCXX20_CONSTEXPR char_type*
+      assign(char_type* __s, size_t __n, char_type __a)
+      {
+	if (__n == 0)
+	  return __s;
+#if __cplusplus >= 202002L
+	if (std::__is_constant_evaluated())
+	  return __gnu_cxx::char_traits<char_type>::assign(__s, __n, __a);
+#endif
+	return static_cast<char_type*>(__builtin_memset(__s, __a, __n));
+      }
+
+      static _GLIBCXX_CONSTEXPR char_type
+      to_char_type(const int_type& __c) _GLIBCXX_NOEXCEPT
+      { return char_type(__c); }
+
+      static _GLIBCXX_CONSTEXPR int_type
+      to_int_type(const char_type& __c) _GLIBCXX_NOEXCEPT
+      { return int_type(__c); }
+
+      static _GLIBCXX_CONSTEXPR bool
+      eq_int_type(const int_type& __c1, const int_type& __c2) _GLIBCXX_NOEXCEPT
+      { return __c1 == __c2; }
+
+      static _GLIBCXX_CONSTEXPR int_type
+      eof() _GLIBCXX_NOEXCEPT
+      { return static_cast<int_type>(-1); }
+
+      static _GLIBCXX_CONSTEXPR int_type
+      not_eof(const int_type& __c) _GLIBCXX_NOEXCEPT
+      { return eq_int_type(__c, eof()) ? 0 : __c; }
+    };
+#endif //_GLIBCXX_USE_CHAR8_T
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#if __cplusplus >= 201103L
+
+#include <cstdint>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  template<>
+    struct char_traits<char16_t>
+    {
+      typedef char16_t          char_type;
+#ifdef _GLIBCXX_USE_C99_STDINT_TR1
+      typedef uint_least16_t    int_type;
+#elif defined __UINT_LEAST16_TYPE__
+      typedef __UINT_LEAST16_TYPE__	    int_type;
+#else
+      typedef make_unsigned<char16_t>::type int_type;
+#endif
+      typedef streamoff         off_type;
+      typedef u16streampos      pos_type;
+      typedef mbstate_t         state_type;
+#if __cpp_lib_three_way_comparison
+      using comparison_category = strong_ordering;
+#endif
+
+      static _GLIBCXX17_CONSTEXPR void
+      assign(char_type& __c1, const char_type& __c2) noexcept
+      {
+#if __cpp_constexpr_dynamic_alloc
+	if (std::__is_constant_evaluated())
+	  std::construct_at(__builtin_addressof(__c1), __c2);
+	else
+#endif
+	__c1 = __c2;
+      }
+
+      static constexpr bool
+      eq(const char_type& __c1, const char_type& __c2) noexcept
+      { return __c1 == __c2; }
+
+      static constexpr bool
+      lt(const char_type& __c1, const char_type& __c2) noexcept
+      { return __c1 < __c2; }
+
+      static _GLIBCXX17_CONSTEXPR int
+      compare(const char_type* __s1, const char_type* __s2, size_t __n)
+      {
+	for (size_t __i = 0; __i < __n; ++__i)
+	  if (lt(__s1[__i], __s2[__i]))
+	    return -1;
+	  else if (lt(__s2[__i], __s1[__i]))
+	    return 1;
+	return 0;
+      }
+
+      static _GLIBCXX17_CONSTEXPR size_t
+      length(const char_type* __s)
+      {
+	size_t __i = 0;
+	while (!eq(__s[__i], char_type()))
+	  ++__i;
+	return __i;
+      }
+
+      static _GLIBCXX17_CONSTEXPR const char_type*
+      find(const char_type* __s, size_t __n, const char_type& __a)
+      {
+	for (size_t __i = 0; __i < __n; ++__i)
+	  if (eq(__s[__i], __a))
+	    return __s + __i;
+	return 0;
+      }
+
+      static _GLIBCXX20_CONSTEXPR char_type*
+      move(char_type* __s1, const char_type* __s2, size_t __n)
+      {
+	if (__n == 0)
+	  return __s1;
+#if __cplusplus >= 202002L
+	if (std::__is_constant_evaluated())
+	  return __gnu_cxx::char_traits<char_type>::move(__s1, __s2, __n);
+#endif
+	return (static_cast<char_type*>
+		(__builtin_memmove(__s1, __s2, __n * sizeof(char_type))));
+      }
+
+      static _GLIBCXX20_CONSTEXPR char_type*
+      copy(char_type* __s1, const char_type* __s2, size_t __n)
+      {
+	if (__n == 0)
+	  return __s1;
+#if __cplusplus >= 202002L
+	if (std::__is_constant_evaluated())
+	  return __gnu_cxx::char_traits<char_type>::copy(__s1, __s2, __n);
+#endif
+	return (static_cast<char_type*>
+		(__builtin_memcpy(__s1, __s2, __n * sizeof(char_type))));
+      }
+
+      static _GLIBCXX20_CONSTEXPR char_type*
+      assign(char_type* __s, size_t __n, char_type __a)
+      {
+	for (size_t __i = 0; __i < __n; ++__i)
+	  assign(__s[__i], __a);
+	return __s;
+      }
+
+      static constexpr char_type
+      to_char_type(const int_type& __c) noexcept
+      { return char_type(__c); }
+
+      static constexpr int_type
+      to_int_type(const char_type& __c) noexcept
+      { return __c == eof() ? int_type(0xfffd) : int_type(__c); }
+
+      static constexpr bool
+      eq_int_type(const int_type& __c1, const int_type& __c2) noexcept
+      { return __c1 == __c2; }
+
+      static constexpr int_type
+      eof() noexcept
+      { return static_cast<int_type>(-1); }
+
+      static constexpr int_type
+      not_eof(const int_type& __c) noexcept
+      { return eq_int_type(__c, eof()) ? 0 : __c; }
+    };
+
+  template<>
+    struct char_traits<char32_t>
+    {
+      typedef char32_t          char_type;
+#ifdef _GLIBCXX_USE_C99_STDINT_TR1
+      typedef uint_least32_t    int_type;
+#elif defined __UINT_LEAST32_TYPE__
+      typedef __UINT_LEAST32_TYPE__	    int_type;
+#else
+      typedef make_unsigned<char32_t>::type int_type;
+#endif
+      typedef streamoff         off_type;
+      typedef u32streampos      pos_type;
+      typedef mbstate_t         state_type;
+#if __cpp_lib_three_way_comparison
+      using comparison_category = strong_ordering;
+#endif
+
+      static _GLIBCXX17_CONSTEXPR void
+      assign(char_type& __c1, const char_type& __c2) noexcept
+      {
+#if __cpp_constexpr_dynamic_alloc
+	if (std::__is_constant_evaluated())
+	  std::construct_at(__builtin_addressof(__c1), __c2);
+	else
+#endif
+	__c1 = __c2;
+      }
+
+      static constexpr bool
+      eq(const char_type& __c1, const char_type& __c2) noexcept
+      { return __c1 == __c2; }
+
+      static constexpr bool
+      lt(const char_type& __c1, const char_type& __c2) noexcept
+      { return __c1 < __c2; }
+
+      static _GLIBCXX17_CONSTEXPR int
+      compare(const char_type* __s1, const char_type* __s2, size_t __n)
+      {
+	for (size_t __i = 0; __i < __n; ++__i)
+	  if (lt(__s1[__i], __s2[__i]))
+	    return -1;
+	  else if (lt(__s2[__i], __s1[__i]))
+	    return 1;
+	return 0;
+      }
+
+      static _GLIBCXX17_CONSTEXPR size_t
+      length(const char_type* __s)
+      {
+	size_t __i = 0;
+	while (!eq(__s[__i], char_type()))
+	  ++__i;
+	return __i;
+      }
+
+      static _GLIBCXX17_CONSTEXPR const char_type*
+      find(const char_type* __s, size_t __n, const char_type& __a)
+      {
+	for (size_t __i = 0; __i < __n; ++__i)
+	  if (eq(__s[__i], __a))
+	    return __s + __i;
+	return 0;
+      }
+
+      static _GLIBCXX20_CONSTEXPR char_type*
+      move(char_type* __s1, const char_type* __s2, size_t __n)
+      {
+	if (__n == 0)
+	  return __s1;
+#if __cplusplus >= 202002L
+	if (std::__is_constant_evaluated())
+	  return __gnu_cxx::char_traits<char_type>::move(__s1, __s2, __n);
+#endif
+	return (static_cast<char_type*>
+		(__builtin_memmove(__s1, __s2, __n * sizeof(char_type))));
+      }
+
+      static _GLIBCXX20_CONSTEXPR char_type*
+      copy(char_type* __s1, const char_type* __s2, size_t __n)
+      { 
+	if (__n == 0)
+	  return __s1;
+#if __cplusplus >= 202002L
+	if (std::__is_constant_evaluated())
+	  return __gnu_cxx::char_traits<char_type>::copy(__s1, __s2, __n);
+#endif
+	return (static_cast<char_type*>
+		(__builtin_memcpy(__s1, __s2, __n * sizeof(char_type))));
+      }
+
+      static _GLIBCXX20_CONSTEXPR char_type*
+      assign(char_type* __s, size_t __n, char_type __a)
+      {
+	for (size_t __i = 0; __i < __n; ++__i)
+	  assign(__s[__i], __a);
+	return __s;
+      }
+
+      static constexpr char_type
+      to_char_type(const int_type& __c) noexcept
+      { return char_type(__c); }
+
+      static constexpr int_type
+      to_int_type(const char_type& __c) noexcept
+      { return int_type(__c); }
+
+      static constexpr bool
+      eq_int_type(const int_type& __c1, const int_type& __c2) noexcept
+      { return __c1 == __c2; }
+
+      static constexpr int_type
+      eof() noexcept
+      { return static_cast<int_type>(-1); }
+
+      static constexpr int_type
+      not_eof(const int_type& __c) noexcept
+      { return eq_int_type(__c, eof()) ? 0 : __c; }
+    };
+
+#if __cpp_lib_three_way_comparison
+  namespace __detail
+  {
+    template<typename _ChTraits>
+      constexpr auto
+      __char_traits_cmp_cat(int __cmp) noexcept
+      {
+	if constexpr (requires { typename _ChTraits::comparison_category; })
+	  {
+	    using _Cat = typename _ChTraits::comparison_category;
+	    static_assert( !is_void_v<common_comparison_category_t<_Cat>> );
+	    return static_cast<_Cat>(__cmp <=> 0);
+	  }
+	else
+	  return static_cast<weak_ordering>(__cmp <=> 0);
+      }
+  } // namespace __detail
+#endif // C++20
+
+#pragma GCC diagnostic pop
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif  // C++11
+
+#endif // _CHAR_TRAITS_H
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@char_traits.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@char_traits.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@charconv.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@charconv.h
new file mode 100644
index 0000000000000000000000000000000000000000..4cae10a72f71764078d2608f655ce4bf91bec42c
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@charconv.h
@@ -0,0 +1,106 @@
+// Numeric conversions (to_string, to_chars) -*- C++ -*-
+
+// Copyright (C) 2017-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/charconv.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{charconv}
+ */
+
+#ifndef _GLIBCXX_CHARCONV_H
+#define _GLIBCXX_CHARCONV_H 1
+
+#pragma GCC system_header
+
+#if __cplusplus >= 201103L
+
+#include <type_traits>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+namespace __detail
+{
+  // Generic implementation for arbitrary bases.
+  template<typename _Tp>
+    _GLIBCXX14_CONSTEXPR unsigned
+    __to_chars_len(_Tp __value, int __base = 10) noexcept
+    {
+      static_assert(is_integral<_Tp>::value, "implementation bug");
+      static_assert(is_unsigned<_Tp>::value, "implementation bug");
+
+      unsigned __n = 1;
+      const unsigned __b2 = __base  * __base;
+      const unsigned __b3 = __b2 * __base;
+      const unsigned long __b4 = __b3 * __base;
+      for (;;)
+	{
+	  if (__value < (unsigned)__base) return __n;
+	  if (__value < __b2) return __n + 1;
+	  if (__value < __b3) return __n + 2;
+	  if (__value < __b4) return __n + 3;
+	  __value /= __b4;
+	  __n += 4;
+	}
+    }
+
+  // Write an unsigned integer value to the range [first,first+len).
+  // The caller is required to provide a buffer of exactly the right size
+  // (which can be determined by the __to_chars_len function).
+  template<typename _Tp>
+    void
+    __to_chars_10_impl(char* __first, unsigned __len, _Tp __val) noexcept
+    {
+      static_assert(is_integral<_Tp>::value, "implementation bug");
+      static_assert(is_unsigned<_Tp>::value, "implementation bug");
+
+      static constexpr char __digits[201] =
+	"0001020304050607080910111213141516171819"
+	"2021222324252627282930313233343536373839"
+	"4041424344454647484950515253545556575859"
+	"6061626364656667686970717273747576777879"
+	"8081828384858687888990919293949596979899";
+      unsigned __pos = __len - 1;
+      while (__val >= 100)
+	{
+	  auto const __num = (__val % 100) * 2;
+	  __val /= 100;
+	  __first[__pos] = __digits[__num + 1];
+	  __first[__pos - 1] = __digits[__num];
+	  __pos -= 2;
+	}
+      if (__val >= 10)
+	{
+	  auto const __num = __val * 2;
+	  __first[1] = __digits[__num + 1];
+	  __first[0] = __digits[__num];
+	}
+      else
+	__first[0] = '0' + __val;
+    }
+
+} // namespace __detail
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+#endif // C++11
+#endif // _GLIBCXX_CHARCONV_H
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@charconv.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@charconv.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@chrono.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@chrono.h
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--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@chrono.h
@@ -0,0 +1,1392 @@
+// chrono::duration and chrono::time_point -*- C++ -*-
+
+// Copyright (C) 2008-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file include/bits/chrono.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{chrono}
+ */
+
+#ifndef _GLIBCXX_CHRONO_H
+#define _GLIBCXX_CHRONO_H 1
+
+#pragma GCC system_header
+
+#if __cplusplus >= 201103L
+
+#include <ratio>
+#include <type_traits>
+#include <limits>
+#include <ctime>
+#include <bits/parse_numbers.h> // for literals support.
+#if __cplusplus >= 202002L
+# include <concepts>
+# include <compare>
+#endif
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+#if __cplusplus >= 201703L
+  namespace filesystem { struct __file_clock; };
+#endif
+
+  namespace chrono
+  {
+    /// @addtogroup chrono
+    /// @{
+
+    /// `chrono::duration` represents a distance between two points in time
+    template<typename _Rep, typename _Period = ratio<1>>
+      struct duration;
+
+    /// `chrono::time_point` represents a point in time as measured by a clock
+    template<typename _Clock, typename _Dur = typename _Clock::duration>
+      struct time_point;
+    /// @}
+  }
+
+  /// @addtogroup chrono
+  /// @{
+
+  // 20.11.4.3 specialization of common_type (for duration, sfinae-friendly)
+
+  /// @cond undocumented
+
+  template<typename _CT, typename _Period1, typename _Period2, typename = void>
+    struct __duration_common_type
+    { };
+
+  template<typename _CT, typename _Period1, typename _Period2>
+    struct __duration_common_type<_CT, _Period1, _Period2,
+				  __void_t<typename _CT::type>>
+    {
+    private:
+      using __gcd_num = __static_gcd<_Period1::num, _Period2::num>;
+      using __gcd_den = __static_gcd<_Period1::den, _Period2::den>;
+      using __cr = typename _CT::type;
+      using __r = ratio<__gcd_num::value,
+			(_Period1::den / __gcd_den::value) * _Period2::den>;
+
+    public:
+      using type = chrono::duration<__cr, typename __r::type>;
+    };
+
+  /// @endcond
+
+  /// @{
+  /// @relates chrono::duration
+
+  /// Specialization of common_type for chrono::duration types.
+  template<typename _Rep1, typename _Period1, typename _Rep2, typename _Period2>
+    struct common_type<chrono::duration<_Rep1, _Period1>,
+		       chrono::duration<_Rep2, _Period2>>
+    : __duration_common_type<common_type<_Rep1, _Rep2>,
+			     typename _Period1::type,
+			     typename _Period2::type>
+    { };
+
+  /// Specialization of common_type for two identical chrono::duration types.
+  template<typename _Rep, typename _Period>
+    struct common_type<chrono::duration<_Rep, _Period>,
+		       chrono::duration<_Rep, _Period>>
+    {
+      using type = chrono::duration<typename common_type<_Rep>::type,
+				    typename _Period::type>;
+    };
+
+  /// Specialization of common_type for one chrono::duration type.
+  template<typename _Rep, typename _Period>
+    struct common_type<chrono::duration<_Rep, _Period>>
+    {
+      using type = chrono::duration<typename common_type<_Rep>::type,
+				    typename _Period::type>;
+    };
+  /// @}
+
+  // 20.11.4.3 specialization of common_type (for time_point, sfinae-friendly)
+
+  /// @cond undocumented
+
+  template<typename _CT, typename _Clock, typename = void>
+    struct __timepoint_common_type
+    { };
+
+  template<typename _CT, typename _Clock>
+    struct __timepoint_common_type<_CT, _Clock, __void_t<typename _CT::type>>
+    {
+      using type = chrono::time_point<_Clock, typename _CT::type>;
+    };
+
+  /// @endcond
+
+  /// @{
+  /// @relates chrono::time_point
+
+  /// Specialization of common_type for chrono::time_point types.
+  template<typename _Clock, typename _Duration1, typename _Duration2>
+    struct common_type<chrono::time_point<_Clock, _Duration1>,
+		       chrono::time_point<_Clock, _Duration2>>
+    : __timepoint_common_type<common_type<_Duration1, _Duration2>, _Clock>
+    { };
+
+  /// Specialization of common_type for two identical chrono::time_point types.
+  template<typename _Clock, typename _Duration>
+    struct common_type<chrono::time_point<_Clock, _Duration>,
+		       chrono::time_point<_Clock, _Duration>>
+    { using type = chrono::time_point<_Clock, _Duration>; };
+
+  /// Specialization of common_type for one chrono::time_point type.
+  template<typename _Clock, typename _Duration>
+    struct common_type<chrono::time_point<_Clock, _Duration>>
+    { using type = chrono::time_point<_Clock, _Duration>; };
+  /// @}
+
+  /// @} group chrono
+
+  namespace chrono
+  {
+    /// @addtogroup chrono
+    /// @{
+
+    /// @cond undocumented
+
+    // Primary template for duration_cast impl.
+    template<typename _ToDur, typename _CF, typename _CR,
+	     bool _NumIsOne = false, bool _DenIsOne = false>
+      struct __duration_cast_impl
+      {
+	template<typename _Rep, typename _Period>
+	  static constexpr _ToDur
+	  __cast(const duration<_Rep, _Period>& __d)
+	  {
+	    typedef typename _ToDur::rep			__to_rep;
+	    return _ToDur(static_cast<__to_rep>(static_cast<_CR>(__d.count())
+	      * static_cast<_CR>(_CF::num)
+	      / static_cast<_CR>(_CF::den)));
+	  }
+      };
+
+    template<typename _ToDur, typename _CF, typename _CR>
+      struct __duration_cast_impl<_ToDur, _CF, _CR, true, true>
+      {
+	template<typename _Rep, typename _Period>
+	  static constexpr _ToDur
+	  __cast(const duration<_Rep, _Period>& __d)
+	  {
+	    typedef typename _ToDur::rep			__to_rep;
+	    return _ToDur(static_cast<__to_rep>(__d.count()));
+	  }
+      };
+
+    template<typename _ToDur, typename _CF, typename _CR>
+      struct __duration_cast_impl<_ToDur, _CF, _CR, true, false>
+      {
+	template<typename _Rep, typename _Period>
+	  static constexpr _ToDur
+	  __cast(const duration<_Rep, _Period>& __d)
+	  {
+	    typedef typename _ToDur::rep			__to_rep;
+	    return _ToDur(static_cast<__to_rep>(
+	      static_cast<_CR>(__d.count()) / static_cast<_CR>(_CF::den)));
+	  }
+      };
+
+    template<typename _ToDur, typename _CF, typename _CR>
+      struct __duration_cast_impl<_ToDur, _CF, _CR, false, true>
+      {
+	template<typename _Rep, typename _Period>
+	  static constexpr _ToDur
+	  __cast(const duration<_Rep, _Period>& __d)
+	  {
+	    typedef typename _ToDur::rep			__to_rep;
+	    return _ToDur(static_cast<__to_rep>(
+	      static_cast<_CR>(__d.count()) * static_cast<_CR>(_CF::num)));
+	  }
+      };
+
+    template<typename _Tp>
+      struct __is_duration
+      : std::false_type
+      { };
+
+    template<typename _Rep, typename _Period>
+      struct __is_duration<duration<_Rep, _Period>>
+      : std::true_type
+      { };
+
+    template<typename _Tp>
+      using __enable_if_is_duration
+	= typename enable_if<__is_duration<_Tp>::value, _Tp>::type;
+
+    template<typename _Tp>
+      using __disable_if_is_duration
+	= typename enable_if<!__is_duration<_Tp>::value, _Tp>::type;
+
+    /// @endcond
+
+    /// duration_cast
+    template<typename _ToDur, typename _Rep, typename _Period>
+      constexpr __enable_if_is_duration<_ToDur>
+      duration_cast(const duration<_Rep, _Period>& __d)
+      {
+	typedef typename _ToDur::period				__to_period;
+	typedef typename _ToDur::rep				__to_rep;
+	typedef ratio_divide<_Period, __to_period> 		__cf;
+	typedef typename common_type<__to_rep, _Rep, intmax_t>::type __cr;
+	typedef  __duration_cast_impl<_ToDur, __cf, __cr,
+				      __cf::num == 1, __cf::den == 1> __dc;
+	return __dc::__cast(__d);
+      }
+
+    /// treat_as_floating_point
+    template<typename _Rep>
+      struct treat_as_floating_point
+      : is_floating_point<_Rep>
+      { };
+
+#if __cplusplus > 201402L
+    template <typename _Rep>
+      inline constexpr bool treat_as_floating_point_v =
+	treat_as_floating_point<_Rep>::value;
+#endif // C++17
+
+#if __cplusplus > 201703L
+    template<typename _Tp>
+      struct is_clock;
+
+    template<typename _Tp>
+      inline constexpr bool is_clock_v = is_clock<_Tp>::value;
+
+#if __cpp_lib_concepts
+    template<typename _Tp>
+      struct is_clock : false_type
+      { };
+
+    template<typename _Tp>
+      requires requires {
+	typename _Tp::rep;
+	typename _Tp::period;
+	typename _Tp::duration;
+	typename _Tp::time_point::clock;
+	typename _Tp::time_point::duration;
+	{ &_Tp::is_steady } -> same_as<const bool*>;
+	{ _Tp::now() } -> same_as<typename _Tp::time_point>;
+	requires same_as<typename _Tp::duration,
+			 duration<typename _Tp::rep, typename _Tp::period>>;
+	requires same_as<typename _Tp::time_point::duration,
+			 typename _Tp::duration>;
+      }
+      struct is_clock<_Tp> : true_type
+      { };
+#else
+    template<typename _Tp, typename = void>
+      struct __is_clock_impl : false_type
+      { };
+
+    template<typename _Tp>
+      struct __is_clock_impl<_Tp,
+			     void_t<typename _Tp::rep, typename _Tp::period,
+				    typename _Tp::duration,
+				    typename _Tp::time_point::duration,
+				    decltype(_Tp::is_steady),
+				    decltype(_Tp::now())>>
+      : __and_<is_same<typename _Tp::duration,
+		       duration<typename _Tp::rep, typename _Tp::period>>,
+	       is_same<typename _Tp::time_point::duration,
+		       typename _Tp::duration>,
+	       is_same<decltype(&_Tp::is_steady), const bool*>,
+	       is_same<decltype(_Tp::now()), typename _Tp::time_point>>::type
+      { };
+
+    template<typename _Tp>
+      struct is_clock : __is_clock_impl<_Tp>::type
+      { };
+#endif
+#endif // C++20
+
+#if __cplusplus >= 201703L
+# define __cpp_lib_chrono 201611L
+
+    template<typename _ToDur, typename _Rep, typename _Period>
+      constexpr __enable_if_is_duration<_ToDur>
+      floor(const duration<_Rep, _Period>& __d)
+      {
+	auto __to = chrono::duration_cast<_ToDur>(__d);
+	if (__to > __d)
+	  return __to - _ToDur{1};
+	return __to;
+      }
+
+    template<typename _ToDur, typename _Rep, typename _Period>
+      constexpr __enable_if_is_duration<_ToDur>
+      ceil(const duration<_Rep, _Period>& __d)
+      {
+	auto __to = chrono::duration_cast<_ToDur>(__d);
+	if (__to < __d)
+	  return __to + _ToDur{1};
+	return __to;
+      }
+
+    template <typename _ToDur, typename _Rep, typename _Period>
+      constexpr enable_if_t<
+	__and_<__is_duration<_ToDur>,
+	       __not_<treat_as_floating_point<typename _ToDur::rep>>>::value,
+	_ToDur>
+      round(const duration<_Rep, _Period>& __d)
+      {
+	_ToDur __t0 = chrono::floor<_ToDur>(__d);
+	_ToDur __t1 = __t0 + _ToDur{1};
+	auto __diff0 = __d - __t0;
+	auto __diff1 = __t1 - __d;
+	if (__diff0 == __diff1)
+	{
+	    if (__t0.count() & 1)
+		return __t1;
+	    return __t0;
+	}
+	else if (__diff0 < __diff1)
+	    return __t0;
+	return __t1;
+      }
+
+    template<typename _Rep, typename _Period>
+      constexpr
+      enable_if_t<numeric_limits<_Rep>::is_signed, duration<_Rep, _Period>>
+      abs(duration<_Rep, _Period> __d)
+      {
+	if (__d >= __d.zero())
+	  return __d;
+	return -__d;
+      }
+
+    // Make chrono::ceil<D> also usable as chrono::__detail::ceil<D>.
+    namespace __detail { using chrono::ceil; }
+
+#else // ! C++17
+
+    // We want to use ceil even when compiling for earlier standards versions.
+    // C++11 only allows a single statement in a constexpr function, so we
+    // need to move the comparison into a separate function, __ceil_impl.
+    namespace __detail
+    {
+      template<typename _Tp, typename _Up>
+	constexpr _Tp
+	__ceil_impl(const _Tp& __t, const _Up& __u)
+	{
+	  return (__t < __u) ? (__t + _Tp{1}) : __t;
+	}
+
+      // C++11-friendly version of std::chrono::ceil<D> for internal use.
+      template<typename _ToDur, typename _Rep, typename _Period>
+	constexpr _ToDur
+	ceil(const duration<_Rep, _Period>& __d)
+	{
+	  return __detail::__ceil_impl(chrono::duration_cast<_ToDur>(__d), __d);
+	}
+    }
+#endif // C++17
+
+    /// duration_values
+    template<typename _Rep>
+      struct duration_values
+      {
+	static constexpr _Rep
+	zero() noexcept
+	{ return _Rep(0); }
+
+	static constexpr _Rep
+	max() noexcept
+	{ return numeric_limits<_Rep>::max(); }
+
+	static constexpr _Rep
+	min() noexcept
+	{ return numeric_limits<_Rep>::lowest(); }
+      };
+
+    /// @cond undocumented
+
+    template<typename _Tp>
+      struct __is_ratio
+      : std::false_type
+      { };
+
+    template<intmax_t _Num, intmax_t _Den>
+      struct __is_ratio<ratio<_Num, _Den>>
+      : std::true_type
+      { };
+
+    /// @endcond
+
+    template<typename _Rep, typename _Period>
+      struct duration
+      {
+      private:
+	template<typename _Rep2>
+	  using __is_float = treat_as_floating_point<_Rep2>;
+
+	static constexpr intmax_t
+	_S_gcd(intmax_t __m, intmax_t __n) noexcept
+	{
+	  // Duration only allows positive periods so we don't need to
+	  // handle negative values here (unlike __static_gcd and std::gcd).
+#if __cplusplus >= 201402L
+	  do
+	    {
+	      intmax_t __rem = __m % __n;
+	      __m = __n;
+	      __n = __rem;
+	    }
+	  while (__n != 0);
+	  return __m;
+#else
+	  // C++11 doesn't allow loops in constexpr functions, but this
+	  // recursive version can be more expensive to evaluate.
+	  return (__n == 0) ? __m : _S_gcd(__n, __m % __n);
+#endif
+	}
+
+	// _GLIBCXX_RESOLVE_LIB_DEFECTS
+	// 2094. overflow shouldn't participate in overload resolution
+	// 3090. What is [2094] intended to mean?
+	// This only produces a valid type if no overflow occurs.
+	template<typename _R1, typename _R2,
+		 intmax_t __gcd1 = _S_gcd(_R1::num, _R2::num),
+		 intmax_t __gcd2 = _S_gcd(_R1::den, _R2::den)>
+	  using __divide = ratio<(_R1::num / __gcd1) * (_R2::den / __gcd2),
+				 (_R1::den / __gcd2) * (_R2::num / __gcd1)>;
+
+	// _Period2 is an exact multiple of _Period
+	template<typename _Period2>
+	  using __is_harmonic
+	    = __bool_constant<__divide<_Period2, _Period>::den == 1>;
+
+      public:
+
+	using rep = _Rep;
+	using period = typename _Period::type;
+
+	static_assert(!__is_duration<_Rep>::value, "rep cannot be a duration");
+	static_assert(__is_ratio<_Period>::value,
+		      "period must be a specialization of ratio");
+	static_assert(_Period::num > 0, "period must be positive");
+
+	// 20.11.5.1 construction / copy / destroy
+	constexpr duration() = default;
+
+	duration(const duration&) = default;
+
+	// _GLIBCXX_RESOLVE_LIB_DEFECTS
+	// 3050. Conversion specification problem in chrono::duration
+	template<typename _Rep2, typename = _Require<
+		 is_convertible<const _Rep2&, rep>,
+		 __or_<__is_float<rep>, __not_<__is_float<_Rep2>>>>>
+	  constexpr explicit duration(const _Rep2& __rep)
+	  : __r(static_cast<rep>(__rep)) { }
+
+	template<typename _Rep2, typename _Period2, typename = _Require<
+		 is_convertible<const _Rep2&, rep>,
+		 __or_<__is_float<rep>,
+		       __and_<__is_harmonic<_Period2>,
+			      __not_<__is_float<_Rep2>>>>>>
+	  constexpr duration(const duration<_Rep2, _Period2>& __d)
+	  : __r(duration_cast<duration>(__d).count()) { }
+
+	~duration() = default;
+	duration& operator=(const duration&) = default;
+
+	// 20.11.5.2 observer
+	constexpr rep
+	count() const
+	{ return __r; }
+
+	// 20.11.5.3 arithmetic
+
+	constexpr duration<typename common_type<rep>::type, period>
+	operator+() const
+	{ return duration<typename common_type<rep>::type, period>(__r); }
+
+	constexpr duration<typename common_type<rep>::type, period>
+	operator-() const
+	{ return duration<typename common_type<rep>::type, period>(-__r); }
+
+	_GLIBCXX17_CONSTEXPR duration&
+	operator++()
+	{
+	  ++__r;
+	  return *this;
+	}
+
+	_GLIBCXX17_CONSTEXPR duration
+	operator++(int)
+	{ return duration(__r++); }
+
+	_GLIBCXX17_CONSTEXPR duration&
+	operator--()
+	{
+	  --__r;
+	  return *this;
+	}
+
+	_GLIBCXX17_CONSTEXPR duration
+	operator--(int)
+	{ return duration(__r--); }
+
+	_GLIBCXX17_CONSTEXPR duration&
+	operator+=(const duration& __d)
+	{
+	  __r += __d.count();
+	  return *this;
+	}
+
+	_GLIBCXX17_CONSTEXPR duration&
+	operator-=(const duration& __d)
+	{
+	  __r -= __d.count();
+	  return *this;
+	}
+
+	_GLIBCXX17_CONSTEXPR duration&
+	operator*=(const rep& __rhs)
+	{
+	  __r *= __rhs;
+	  return *this;
+	}
+
+	_GLIBCXX17_CONSTEXPR duration&
+	operator/=(const rep& __rhs)
+	{
+	  __r /= __rhs;
+	  return *this;
+	}
+
+	// DR 934.
+	template<typename _Rep2 = rep>
+	  _GLIBCXX17_CONSTEXPR
+	  typename enable_if<!treat_as_floating_point<_Rep2>::value,
+			     duration&>::type
+	  operator%=(const rep& __rhs)
+	  {
+	    __r %= __rhs;
+	    return *this;
+	  }
+
+	template<typename _Rep2 = rep>
+	  _GLIBCXX17_CONSTEXPR
+	  typename enable_if<!treat_as_floating_point<_Rep2>::value,
+			     duration&>::type
+	  operator%=(const duration& __d)
+	  {
+	    __r %= __d.count();
+	    return *this;
+	  }
+
+	// 20.11.5.4 special values
+	static constexpr duration
+	zero() noexcept
+	{ return duration(duration_values<rep>::zero()); }
+
+	static constexpr duration
+	min() noexcept
+	{ return duration(duration_values<rep>::min()); }
+
+	static constexpr duration
+	max() noexcept
+	{ return duration(duration_values<rep>::max()); }
+
+      private:
+	rep __r;
+      };
+
+    /// @{
+    /// @relates std::chrono::duration
+
+    /// The sum of two durations.
+    template<typename _Rep1, typename _Period1,
+	     typename _Rep2, typename _Period2>
+      constexpr typename common_type<duration<_Rep1, _Period1>,
+				     duration<_Rep2, _Period2>>::type
+      operator+(const duration<_Rep1, _Period1>& __lhs,
+		const duration<_Rep2, _Period2>& __rhs)
+      {
+	typedef duration<_Rep1, _Period1>			__dur1;
+	typedef duration<_Rep2, _Period2>			__dur2;
+	typedef typename common_type<__dur1,__dur2>::type	__cd;
+	return __cd(__cd(__lhs).count() + __cd(__rhs).count());
+      }
+
+    /// The difference between two durations.
+    template<typename _Rep1, typename _Period1,
+	     typename _Rep2, typename _Period2>
+      constexpr typename common_type<duration<_Rep1, _Period1>,
+				     duration<_Rep2, _Period2>>::type
+      operator-(const duration<_Rep1, _Period1>& __lhs,
+		const duration<_Rep2, _Period2>& __rhs)
+      {
+	typedef duration<_Rep1, _Period1>			__dur1;
+	typedef duration<_Rep2, _Period2>			__dur2;
+	typedef typename common_type<__dur1,__dur2>::type	__cd;
+	return __cd(__cd(__lhs).count() - __cd(__rhs).count());
+      }
+
+    /// @}
+
+    /// @cond undocumented
+
+    // SFINAE helper to obtain common_type<_Rep1, _Rep2> only if _Rep2
+    // is implicitly convertible to it.
+    // _GLIBCXX_RESOLVE_LIB_DEFECTS
+    // 3050. Conversion specification problem in chrono::duration constructor
+    template<typename _Rep1, typename _Rep2,
+	     typename _CRep = typename common_type<_Rep1, _Rep2>::type>
+      using __common_rep_t = typename
+	enable_if<is_convertible<const _Rep2&, _CRep>::value, _CRep>::type;
+
+    /// @endcond
+
+    /** @{
+     * Arithmetic operators for chrono::duration
+     * @relates std::chrono::duration
+     */
+
+    template<typename _Rep1, typename _Period, typename _Rep2>
+      constexpr duration<__common_rep_t<_Rep1, _Rep2>, _Period>
+      operator*(const duration<_Rep1, _Period>& __d, const _Rep2& __s)
+      {
+	typedef duration<typename common_type<_Rep1, _Rep2>::type, _Period>
+	  __cd;
+	return __cd(__cd(__d).count() * __s);
+      }
+
+    template<typename _Rep1, typename _Rep2, typename _Period>
+      constexpr duration<__common_rep_t<_Rep2, _Rep1>, _Period>
+      operator*(const _Rep1& __s, const duration<_Rep2, _Period>& __d)
+      { return __d * __s; }
+
+    template<typename _Rep1, typename _Period, typename _Rep2>
+      constexpr
+      duration<__common_rep_t<_Rep1, __disable_if_is_duration<_Rep2>>, _Period>
+      operator/(const duration<_Rep1, _Period>& __d, const _Rep2& __s)
+      {
+	typedef duration<typename common_type<_Rep1, _Rep2>::type, _Period>
+	  __cd;
+	return __cd(__cd(__d).count() / __s);
+      }
+
+    template<typename _Rep1, typename _Period1,
+	     typename _Rep2, typename _Period2>
+      constexpr typename common_type<_Rep1, _Rep2>::type
+      operator/(const duration<_Rep1, _Period1>& __lhs,
+		const duration<_Rep2, _Period2>& __rhs)
+      {
+	typedef duration<_Rep1, _Period1>			__dur1;
+	typedef duration<_Rep2, _Period2>			__dur2;
+	typedef typename common_type<__dur1,__dur2>::type	__cd;
+	return __cd(__lhs).count() / __cd(__rhs).count();
+      }
+
+    // DR 934.
+    template<typename _Rep1, typename _Period, typename _Rep2>
+      constexpr
+      duration<__common_rep_t<_Rep1, __disable_if_is_duration<_Rep2>>, _Period>
+      operator%(const duration<_Rep1, _Period>& __d, const _Rep2& __s)
+      {
+	typedef duration<typename common_type<_Rep1, _Rep2>::type, _Period>
+	  __cd;
+	return __cd(__cd(__d).count() % __s);
+      }
+
+    template<typename _Rep1, typename _Period1,
+	     typename _Rep2, typename _Period2>
+      constexpr typename common_type<duration<_Rep1, _Period1>,
+				     duration<_Rep2, _Period2>>::type
+      operator%(const duration<_Rep1, _Period1>& __lhs,
+		const duration<_Rep2, _Period2>& __rhs)
+      {
+	typedef duration<_Rep1, _Period1>			__dur1;
+	typedef duration<_Rep2, _Period2>			__dur2;
+	typedef typename common_type<__dur1,__dur2>::type	__cd;
+	return __cd(__cd(__lhs).count() % __cd(__rhs).count());
+      }
+    /// @}
+
+    // comparisons
+
+    /** @{
+     * Comparisons for chrono::duration
+     * @relates std::chrono::duration
+     */
+
+    template<typename _Rep1, typename _Period1,
+	     typename _Rep2, typename _Period2>
+      constexpr bool
+      operator==(const duration<_Rep1, _Period1>& __lhs,
+		 const duration<_Rep2, _Period2>& __rhs)
+      {
+	typedef duration<_Rep1, _Period1>			__dur1;
+	typedef duration<_Rep2, _Period2>			__dur2;
+	typedef typename common_type<__dur1,__dur2>::type	__ct;
+	return __ct(__lhs).count() == __ct(__rhs).count();
+      }
+
+    template<typename _Rep1, typename _Period1,
+	     typename _Rep2, typename _Period2>
+      constexpr bool
+      operator<(const duration<_Rep1, _Period1>& __lhs,
+		const duration<_Rep2, _Period2>& __rhs)
+      {
+	typedef duration<_Rep1, _Period1>			__dur1;
+	typedef duration<_Rep2, _Period2>			__dur2;
+	typedef typename common_type<__dur1,__dur2>::type	__ct;
+	return __ct(__lhs).count() < __ct(__rhs).count();
+      }
+
+#if __cpp_lib_three_way_comparison
+    template<typename _Rep1, typename _Period1,
+	     typename _Rep2, typename _Period2>
+      requires three_way_comparable<common_type_t<_Rep1, _Rep2>>
+      constexpr auto
+      operator<=>(const duration<_Rep1, _Period1>& __lhs,
+		  const duration<_Rep2, _Period2>& __rhs)
+      {
+	using __ct = common_type_t<duration<_Rep1, _Period1>,
+				   duration<_Rep2, _Period2>>;
+	return __ct(__lhs).count() <=> __ct(__rhs).count();
+      }
+#else
+    template<typename _Rep1, typename _Period1,
+	     typename _Rep2, typename _Period2>
+      constexpr bool
+      operator!=(const duration<_Rep1, _Period1>& __lhs,
+		 const duration<_Rep2, _Period2>& __rhs)
+      { return !(__lhs == __rhs); }
+#endif
+
+    template<typename _Rep1, typename _Period1,
+	     typename _Rep2, typename _Period2>
+      constexpr bool
+      operator<=(const duration<_Rep1, _Period1>& __lhs,
+		 const duration<_Rep2, _Period2>& __rhs)
+      { return !(__rhs < __lhs); }
+
+    template<typename _Rep1, typename _Period1,
+	     typename _Rep2, typename _Period2>
+      constexpr bool
+      operator>(const duration<_Rep1, _Period1>& __lhs,
+		const duration<_Rep2, _Period2>& __rhs)
+      { return __rhs < __lhs; }
+
+    template<typename _Rep1, typename _Period1,
+	     typename _Rep2, typename _Period2>
+      constexpr bool
+      operator>=(const duration<_Rep1, _Period1>& __lhs,
+		 const duration<_Rep2, _Period2>& __rhs)
+      { return !(__lhs < __rhs); }
+
+    /// @}
+
+    /// @cond undocumented
+#ifdef _GLIBCXX_USE_C99_STDINT_TR1
+# define _GLIBCXX_CHRONO_INT64_T int64_t
+#elif defined __INT64_TYPE__
+# define _GLIBCXX_CHRONO_INT64_T __INT64_TYPE__
+#else
+    static_assert(std::numeric_limits<unsigned long long>::digits >= 64,
+	"Representation type for nanoseconds must have at least 64 bits");
+# define _GLIBCXX_CHRONO_INT64_T long long
+#endif
+    /// @endcond
+
+    /// nanoseconds
+    using nanoseconds	= duration<_GLIBCXX_CHRONO_INT64_T, nano>;
+
+    /// microseconds
+    using microseconds	= duration<_GLIBCXX_CHRONO_INT64_T, micro>;
+
+    /// milliseconds
+    using milliseconds	= duration<_GLIBCXX_CHRONO_INT64_T, milli>;
+
+    /// seconds
+    using seconds	= duration<_GLIBCXX_CHRONO_INT64_T>;
+
+    /// minutes
+    using minutes	= duration<_GLIBCXX_CHRONO_INT64_T, ratio< 60>>;
+
+    /// hours
+    using hours		= duration<_GLIBCXX_CHRONO_INT64_T, ratio<3600>>;
+
+#if __cplusplus > 201703L
+    /// days
+    using days		= duration<_GLIBCXX_CHRONO_INT64_T, ratio<86400>>;
+
+    /// weeks
+    using weeks		= duration<_GLIBCXX_CHRONO_INT64_T, ratio<604800>>;
+
+    /// years
+    using years		= duration<_GLIBCXX_CHRONO_INT64_T, ratio<31556952>>;
+
+    /// months
+    using months	= duration<_GLIBCXX_CHRONO_INT64_T, ratio<2629746>>;
+#endif // C++20
+
+#undef _GLIBCXX_CHRONO_INT64_T
+
+    template<typename _Clock, typename _Dur>
+      struct time_point
+      {
+	static_assert(__is_duration<_Dur>::value,
+	    "duration must be a specialization of std::chrono::duration");
+
+	typedef _Clock						clock;
+	typedef _Dur						duration;
+	typedef typename duration::rep				rep;
+	typedef typename duration::period			period;
+
+	constexpr time_point() : __d(duration::zero())
+	{ }
+
+	constexpr explicit time_point(const duration& __dur)
+	: __d(__dur)
+	{ }
+
+	// conversions
+	template<typename _Dur2,
+		 typename = _Require<is_convertible<_Dur2, _Dur>>>
+	  constexpr time_point(const time_point<clock, _Dur2>& __t)
+	  : __d(__t.time_since_epoch())
+	  { }
+
+	// observer
+	constexpr duration
+	time_since_epoch() const
+	{ return __d; }
+
+#if __cplusplus > 201703L
+	constexpr time_point&
+	operator++()
+	{
+	  ++__d;
+	  return *this;
+	}
+
+	constexpr time_point
+	operator++(int)
+	{ return time_point{__d++}; }
+
+	constexpr time_point&
+	operator--()
+	{
+	  --__d;
+	  return *this;
+	}
+
+	constexpr time_point
+	operator--(int)
+	{ return time_point{__d--}; }
+#endif
+
+	// arithmetic
+	_GLIBCXX17_CONSTEXPR time_point&
+	operator+=(const duration& __dur)
+	{
+	  __d += __dur;
+	  return *this;
+	}
+
+	_GLIBCXX17_CONSTEXPR time_point&
+	operator-=(const duration& __dur)
+	{
+	  __d -= __dur;
+	  return *this;
+	}
+
+	// special values
+	static constexpr time_point
+	min() noexcept
+	{ return time_point(duration::min()); }
+
+	static constexpr time_point
+	max() noexcept
+	{ return time_point(duration::max()); }
+
+      private:
+	duration __d;
+      };
+
+    /// time_point_cast
+    template<typename _ToDur, typename _Clock, typename _Dur>
+      constexpr typename enable_if<__is_duration<_ToDur>::value,
+				   time_point<_Clock, _ToDur>>::type
+      time_point_cast(const time_point<_Clock, _Dur>& __t)
+      {
+	typedef time_point<_Clock, _ToDur>			__time_point;
+	return __time_point(duration_cast<_ToDur>(__t.time_since_epoch()));
+      }
+
+#if __cplusplus > 201402L
+    template<typename _ToDur, typename _Clock, typename _Dur>
+      constexpr
+      enable_if_t<__is_duration<_ToDur>::value, time_point<_Clock, _ToDur>>
+      floor(const time_point<_Clock, _Dur>& __tp)
+      {
+	return time_point<_Clock, _ToDur>{
+	    chrono::floor<_ToDur>(__tp.time_since_epoch())};
+      }
+
+    template<typename _ToDur, typename _Clock, typename _Dur>
+      constexpr
+      enable_if_t<__is_duration<_ToDur>::value, time_point<_Clock, _ToDur>>
+      ceil(const time_point<_Clock, _Dur>& __tp)
+      {
+	return time_point<_Clock, _ToDur>{
+	    chrono::ceil<_ToDur>(__tp.time_since_epoch())};
+      }
+
+    template<typename _ToDur, typename _Clock, typename _Dur>
+      constexpr enable_if_t<
+	__and_<__is_duration<_ToDur>,
+	       __not_<treat_as_floating_point<typename _ToDur::rep>>>::value,
+	time_point<_Clock, _ToDur>>
+      round(const time_point<_Clock, _Dur>& __tp)
+      {
+	return time_point<_Clock, _ToDur>{
+	    chrono::round<_ToDur>(__tp.time_since_epoch())};
+      }
+#endif // C++17
+
+    /// @{
+    /// @relates time_point
+
+    /// Adjust a time point forwards by the given duration.
+    template<typename _Clock, typename _Dur1,
+	     typename _Rep2, typename _Period2>
+      constexpr time_point<_Clock,
+	typename common_type<_Dur1, duration<_Rep2, _Period2>>::type>
+      operator+(const time_point<_Clock, _Dur1>& __lhs,
+		const duration<_Rep2, _Period2>& __rhs)
+      {
+	typedef duration<_Rep2, _Period2>			__dur2;
+	typedef typename common_type<_Dur1,__dur2>::type	__ct;
+	typedef time_point<_Clock, __ct>			__time_point;
+	return __time_point(__lhs.time_since_epoch() + __rhs);
+      }
+
+    /// Adjust a time point forwards by the given duration.
+    template<typename _Rep1, typename _Period1,
+	     typename _Clock, typename _Dur2>
+      constexpr time_point<_Clock,
+	typename common_type<duration<_Rep1, _Period1>, _Dur2>::type>
+      operator+(const duration<_Rep1, _Period1>& __lhs,
+		const time_point<_Clock, _Dur2>& __rhs)
+      {
+	typedef duration<_Rep1, _Period1>			__dur1;
+	typedef typename common_type<__dur1,_Dur2>::type	__ct;
+	typedef time_point<_Clock, __ct>			__time_point;
+	return __time_point(__rhs.time_since_epoch() + __lhs);
+      }
+
+    /// Adjust a time point backwards by the given duration.
+    template<typename _Clock, typename _Dur1,
+	     typename _Rep2, typename _Period2>
+      constexpr time_point<_Clock,
+	typename common_type<_Dur1, duration<_Rep2, _Period2>>::type>
+      operator-(const time_point<_Clock, _Dur1>& __lhs,
+		const duration<_Rep2, _Period2>& __rhs)
+      {
+	typedef duration<_Rep2, _Period2>			__dur2;
+	typedef typename common_type<_Dur1,__dur2>::type	__ct;
+	typedef time_point<_Clock, __ct>			__time_point;
+	return __time_point(__lhs.time_since_epoch() -__rhs);
+      }
+
+    /// The difference between two time points (as a duration)
+    template<typename _Clock, typename _Dur1, typename _Dur2>
+      constexpr typename common_type<_Dur1, _Dur2>::type
+      operator-(const time_point<_Clock, _Dur1>& __lhs,
+		const time_point<_Clock, _Dur2>& __rhs)
+      { return __lhs.time_since_epoch() - __rhs.time_since_epoch(); }
+    /// @}
+
+    /** @{
+     * Comparisons for time_point
+     * @relates chrono::time_point
+     */
+
+    template<typename _Clock, typename _Dur1, typename _Dur2>
+      constexpr bool
+      operator==(const time_point<_Clock, _Dur1>& __lhs,
+		 const time_point<_Clock, _Dur2>& __rhs)
+      { return __lhs.time_since_epoch() == __rhs.time_since_epoch(); }
+
+#if __cpp_lib_three_way_comparison
+    template<typename _Clock, typename _Dur1,
+	     three_way_comparable_with<_Dur1> _Dur2>
+      constexpr auto
+      operator<=>(const time_point<_Clock, _Dur1>& __lhs,
+		  const time_point<_Clock, _Dur2>& __rhs)
+      { return __lhs.time_since_epoch() <=> __rhs.time_since_epoch(); }
+#else
+    template<typename _Clock, typename _Dur1, typename _Dur2>
+      constexpr bool
+      operator!=(const time_point<_Clock, _Dur1>& __lhs,
+		 const time_point<_Clock, _Dur2>& __rhs)
+      { return !(__lhs == __rhs); }
+#endif
+
+    template<typename _Clock, typename _Dur1, typename _Dur2>
+      constexpr bool
+      operator<(const time_point<_Clock, _Dur1>& __lhs,
+		const time_point<_Clock, _Dur2>& __rhs)
+      { return  __lhs.time_since_epoch() < __rhs.time_since_epoch(); }
+
+    template<typename _Clock, typename _Dur1, typename _Dur2>
+      constexpr bool
+      operator<=(const time_point<_Clock, _Dur1>& __lhs,
+		 const time_point<_Clock, _Dur2>& __rhs)
+      { return !(__rhs < __lhs); }
+
+    template<typename _Clock, typename _Dur1, typename _Dur2>
+      constexpr bool
+      operator>(const time_point<_Clock, _Dur1>& __lhs,
+		const time_point<_Clock, _Dur2>& __rhs)
+      { return __rhs < __lhs; }
+
+    template<typename _Clock, typename _Dur1, typename _Dur2>
+      constexpr bool
+      operator>=(const time_point<_Clock, _Dur1>& __lhs,
+		 const time_point<_Clock, _Dur2>& __rhs)
+      { return !(__lhs < __rhs); }
+
+    /// @}
+    /// @} group chrono
+
+    // Clocks.
+
+    // Why nanosecond resolution as the default?
+    // Why have std::system_clock always count in the highest
+    // resolution (ie nanoseconds), even if on some OSes the low 3
+    // or 9 decimal digits will be always zero? This allows later
+    // implementations to change the system_clock::now()
+    // implementation any time to provide better resolution without
+    // changing function signature or units.
+
+    // To support the (forward) evolution of the library's defined
+    // clocks, wrap inside inline namespace so that the current
+    // defintions of system_clock, steady_clock, and
+    // high_resolution_clock types are uniquely mangled. This way, new
+    // code can use the latests clocks, while the library can contain
+    // compatibility definitions for previous versions.  At some
+    // point, when these clocks settle down, the inlined namespaces
+    // can be removed.  XXX GLIBCXX_ABI Deprecated
+    inline namespace _V2 {
+
+    /**
+     *  @brief System clock.
+     *
+     *  Time returned represents wall time from the system-wide clock.
+     *  @ingroup chrono
+    */
+    struct system_clock
+    {
+      typedef chrono::nanoseconds				duration;
+      typedef duration::rep					rep;
+      typedef duration::period					period;
+      typedef chrono::time_point<system_clock, duration> 	time_point;
+
+      static_assert(system_clock::duration::min()
+		    < system_clock::duration::zero(),
+		    "a clock's minimum duration cannot be less than its epoch");
+
+      static constexpr bool is_steady = false;
+
+      static time_point
+      now() noexcept;
+
+      // Map to C API
+      static std::time_t
+      to_time_t(const time_point& __t) noexcept
+      {
+	return std::time_t(duration_cast<chrono::seconds>
+			   (__t.time_since_epoch()).count());
+      }
+
+      static time_point
+      from_time_t(std::time_t __t) noexcept
+      {
+	typedef chrono::time_point<system_clock, seconds>	__from;
+	return time_point_cast<system_clock::duration>
+	       (__from(chrono::seconds(__t)));
+      }
+    };
+
+
+    /**
+     *  @brief Monotonic clock
+     *
+     *  Time returned has the property of only increasing at a uniform rate.
+     *  @ingroup chrono
+    */
+    struct steady_clock
+    {
+      typedef chrono::nanoseconds				duration;
+      typedef duration::rep					rep;
+      typedef duration::period					period;
+      typedef chrono::time_point<steady_clock, duration>	time_point;
+
+      static constexpr bool is_steady = true;
+
+      static time_point
+      now() noexcept;
+    };
+
+
+    /**
+     *  @brief Highest-resolution clock
+     *
+     *  This is the clock "with the shortest tick period." Alias to
+     *  std::system_clock until higher-than-nanosecond definitions
+     *  become feasible.
+     *  @ingroup chrono
+    */
+    using high_resolution_clock = system_clock;
+
+    } // end inline namespace _V2
+
+#if __cplusplus >= 202002L
+    /// @addtogroup chrono
+    /// @{
+    template<typename _Duration>
+      using sys_time = time_point<system_clock, _Duration>;
+    using sys_seconds = sys_time<seconds>;
+    using sys_days = sys_time<days>;
+
+    using file_clock = ::std::filesystem::__file_clock;
+
+    template<typename _Duration>
+      using file_time = time_point<file_clock, _Duration>;
+
+    template<> struct is_clock<system_clock> : true_type { };
+    template<> struct is_clock<steady_clock> : true_type { };
+    template<> struct is_clock<file_clock> : true_type { };
+
+    template<> inline constexpr bool is_clock_v<system_clock> = true;
+    template<> inline constexpr bool is_clock_v<steady_clock> = true;
+    template<> inline constexpr bool is_clock_v<file_clock> = true;
+    /// @}
+#endif // C++20
+  } // namespace chrono
+
+#if __cplusplus >= 201402L
+#define __cpp_lib_chrono_udls 201304L
+
+  inline namespace literals
+  {
+  /** ISO C++ 2014  namespace for suffixes for duration literals.
+   *
+   * These suffixes can be used to create `chrono::duration` values with
+   * tick periods of hours, minutes, seconds, milliseconds, microseconds
+   * or nanoseconds. For example, `std::chrono::seconds(5)` can be written
+   * as `5s` after making the suffix visible in the current scope.
+   * The suffixes can be made visible by a using-directive or
+   * using-declaration such as:
+   *  - `using namespace std::chrono_literals;`
+   *  - `using namespace std::literals;`
+   *  - `using namespace std::chrono;`
+   *  - `using namespace std;`
+   *  - `using std::chrono_literals::operator""s;`
+   *
+   * The result of these suffixes on an integer literal is one of the
+   * standard typedefs such as `std::chrono::hours`.
+   * The result on a floating-point literal is a duration type with the
+   * specified tick period and an unspecified floating-point representation,
+   * for example `1.5e2ms` might be equivalent to
+   * `chrono::duration<long double, chrono::milli>(1.5e2)`.
+   *
+   * @since C+14
+   * @ingroup chrono
+   */
+  inline namespace chrono_literals
+  {
+    /// @addtogroup chrono
+    /// @{
+
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wliteral-suffix"
+    /// @cond undocumented
+    template<typename _Dur, char... _Digits>
+      constexpr _Dur __check_overflow()
+      {
+	using _Val = __parse_int::_Parse_int<_Digits...>;
+	constexpr typename _Dur::rep __repval = _Val::value;
+	static_assert(__repval >= 0 && __repval == _Val::value,
+		      "literal value cannot be represented by duration type");
+	return _Dur(__repval);
+      }
+    /// @endcond
+
+    /// Literal suffix for durations representing non-integer hours
+    constexpr chrono::duration<long double, ratio<3600,1>>
+    operator""h(long double __hours)
+    { return chrono::duration<long double, ratio<3600,1>>{__hours}; }
+
+    /// Literal suffix for durations of type `std::chrono::hours`
+    template <char... _Digits>
+      constexpr chrono::hours
+      operator""h()
+      { return __check_overflow<chrono::hours, _Digits...>(); }
+
+    /// Literal suffix for durations representing non-integer minutes
+    constexpr chrono::duration<long double, ratio<60,1>>
+    operator""min(long double __mins)
+    { return chrono::duration<long double, ratio<60,1>>{__mins}; }
+
+    /// Literal suffix for durations of type `std::chrono::minutes`
+    template <char... _Digits>
+      constexpr chrono::minutes
+      operator""min()
+      { return __check_overflow<chrono::minutes, _Digits...>(); }
+
+    /// Literal suffix for durations representing non-integer seconds
+    constexpr chrono::duration<long double>
+    operator""s(long double __secs)
+    { return chrono::duration<long double>{__secs}; }
+
+    /// Literal suffix for durations of type `std::chrono::seconds`
+    template <char... _Digits>
+      constexpr chrono::seconds
+      operator""s()
+      { return __check_overflow<chrono::seconds, _Digits...>(); }
+
+    /// Literal suffix for durations representing non-integer milliseconds
+    constexpr chrono::duration<long double, milli>
+    operator""ms(long double __msecs)
+    { return chrono::duration<long double, milli>{__msecs}; }
+
+    /// Literal suffix for durations of type `std::chrono::milliseconds`
+    template <char... _Digits>
+      constexpr chrono::milliseconds
+      operator""ms()
+      { return __check_overflow<chrono::milliseconds, _Digits...>(); }
+
+    /// Literal suffix for durations representing non-integer microseconds
+    constexpr chrono::duration<long double, micro>
+    operator""us(long double __usecs)
+    { return chrono::duration<long double, micro>{__usecs}; }
+
+    /// Literal suffix for durations of type `std::chrono::microseconds`
+    template <char... _Digits>
+      constexpr chrono::microseconds
+      operator""us()
+      { return __check_overflow<chrono::microseconds, _Digits...>(); }
+
+    /// Literal suffix for durations representing non-integer nanoseconds
+    constexpr chrono::duration<long double, nano>
+    operator""ns(long double __nsecs)
+    { return chrono::duration<long double, nano>{__nsecs}; }
+
+    /// Literal suffix for durations of type `std::chrono::nanoseconds`
+    template <char... _Digits>
+      constexpr chrono::nanoseconds
+      operator""ns()
+      { return __check_overflow<chrono::nanoseconds, _Digits...>(); }
+
+#pragma GCC diagnostic pop
+    /// @}
+  } // inline namespace chrono_literals
+  } // inline namespace literals
+
+  namespace chrono
+  {
+    using namespace literals::chrono_literals;
+  } // namespace chrono
+#endif // C++14
+
+#if __cplusplus >= 201703L
+  namespace filesystem
+  {
+    struct __file_clock
+    {
+      using duration                  = chrono::nanoseconds;
+      using rep                       = duration::rep;
+      using period                    = duration::period;
+      using time_point                = chrono::time_point<__file_clock>;
+      static constexpr bool is_steady = false;
+
+      static time_point
+      now() noexcept
+      { return _S_from_sys(chrono::system_clock::now()); }
+
+#if __cplusplus > 201703L
+      template<typename _Dur>
+	static
+	chrono::file_time<_Dur>
+	from_sys(const chrono::sys_time<_Dur>& __t) noexcept
+	{ return _S_from_sys(__t); }
+
+      // For internal use only
+      template<typename _Dur>
+	static
+	chrono::sys_time<_Dur>
+	to_sys(const chrono::file_time<_Dur>& __t) noexcept
+	{ return _S_to_sys(__t); }
+#endif // C++20
+
+    private:
+      using __sys_clock = chrono::system_clock;
+
+      // This clock's (unspecified) epoch is 2174-01-01 00:00:00 UTC.
+      // A signed 64-bit duration with nanosecond resolution gives roughly
+      // +/- 292 years, which covers the 1901-2446 date range for ext4.
+      static constexpr chrono::seconds _S_epoch_diff{6437664000};
+
+    protected:
+      // For internal use only
+      template<typename _Dur>
+	static
+	chrono::time_point<__file_clock, _Dur>
+	_S_from_sys(const chrono::time_point<__sys_clock, _Dur>& __t) noexcept
+	{
+	  using __file_time = chrono::time_point<__file_clock, _Dur>;
+	  return __file_time{__t.time_since_epoch()} - _S_epoch_diff;
+	}
+
+      // For internal use only
+      template<typename _Dur>
+	static
+	chrono::time_point<__sys_clock, _Dur>
+	_S_to_sys(const chrono::time_point<__file_clock, _Dur>& __t) noexcept
+	{
+	  using __sys_time = chrono::time_point<__sys_clock, _Dur>;
+	  return __sys_time{__t.time_since_epoch()} + _S_epoch_diff;
+	}
+    };
+  } // namespace filesystem
+#endif // C++17
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif // C++11
+
+#endif //_GLIBCXX_CHRONO_H
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@@ -0,0 +1,843 @@
+// Locale support (codecvt) -*- C++ -*-
+
+// Copyright (C) 2000-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/codecvt.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{locale}
+ */
+
+//
+// ISO C++ 14882: 22.2.1.5 Template class codecvt
+//
+
+// Written by Benjamin Kosnik <bkoz@redhat.com>
+
+#ifndef _CODECVT_H
+#define _CODECVT_H 1
+
+#pragma GCC system_header
+
+#include <bits/c++config.h>
+#include <bits/locale_classes.h> // locale::facet
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /// Empty base class for codecvt facet [22.2.1.5].
+  class codecvt_base
+  {
+  public:
+    enum result
+    {
+      ok,
+      partial,
+      error,
+      noconv
+    };
+  };
+
+  /**
+   *  @brief  Common base for codecvt functions.
+   *
+   *  This template class provides implementations of the public functions
+   *  that forward to the protected virtual functions.
+   *
+   *  This template also provides abstract stubs for the protected virtual
+   *  functions.
+  */
+  template<typename _InternT, typename _ExternT, typename _StateT>
+    class __codecvt_abstract_base
+    : public locale::facet, public codecvt_base
+    {
+    public:
+      // Types:
+      typedef codecvt_base::result	result;
+      typedef _InternT			intern_type;
+      typedef _ExternT			extern_type;
+      typedef _StateT			state_type;
+
+      // 22.2.1.5.1 codecvt members
+      /**
+       *  @brief  Convert from internal to external character set.
+       *
+       *  Converts input string of intern_type to output string of
+       *  extern_type.  This is analogous to wcsrtombs.  It does this by
+       *  calling codecvt::do_out.
+       *
+       *  The source and destination character sets are determined by the
+       *  facet's locale, internal and external types.
+       *
+       *  The characters in [from,from_end) are converted and written to
+       *  [to,to_end).  from_next and to_next are set to point to the
+       *  character following the last successfully converted character,
+       *  respectively.  If the result needed no conversion, from_next and
+       *  to_next are not affected.
+       *
+       *  The @a state argument should be initialized if the input is at the
+       *  beginning and carried from a previous call if continuing
+       *  conversion.  There are no guarantees about how @a state is used.
+       *
+       *  The result returned is a member of codecvt_base::result.  If
+       *  all the input is converted, returns codecvt_base::ok.  If no
+       *  conversion is necessary, returns codecvt_base::noconv.  If
+       *  the input ends early or there is insufficient space in the
+       *  output, returns codecvt_base::partial.  Otherwise the
+       *  conversion failed and codecvt_base::error is returned.
+       *
+       *  @param  __state  Persistent conversion state data.
+       *  @param  __from  Start of input.
+       *  @param  __from_end  End of input.
+       *  @param  __from_next  Returns start of unconverted data.
+       *  @param  __to  Start of output buffer.
+       *  @param  __to_end  End of output buffer.
+       *  @param  __to_next  Returns start of unused output area.
+       *  @return  codecvt_base::result.
+      */
+      result
+      out(state_type& __state, const intern_type* __from,
+	  const intern_type* __from_end, const intern_type*& __from_next,
+	  extern_type* __to, extern_type* __to_end,
+	  extern_type*& __to_next) const
+      {
+	return this->do_out(__state, __from, __from_end, __from_next,
+			    __to, __to_end, __to_next);
+      }
+
+      /**
+       *  @brief  Reset conversion state.
+       *
+       *  Writes characters to output that would restore @a state to initial
+       *  conditions.  The idea is that if a partial conversion occurs, then
+       *  the converting the characters written by this function would leave
+       *  the state in initial conditions, rather than partial conversion
+       *  state.  It does this by calling codecvt::do_unshift().
+       *
+       *  For example, if 4 external characters always converted to 1 internal
+       *  character, and input to in() had 6 external characters with state
+       *  saved, this function would write two characters to the output and
+       *  set the state to initialized conditions.
+       *
+       *  The source and destination character sets are determined by the
+       *  facet's locale, internal and external types.
+       *
+       *  The result returned is a member of codecvt_base::result.  If the
+       *  state could be reset and data written, returns codecvt_base::ok.  If
+       *  no conversion is necessary, returns codecvt_base::noconv.  If the
+       *  output has insufficient space, returns codecvt_base::partial.
+       *  Otherwise the reset failed and codecvt_base::error is returned.
+       *
+       *  @param  __state  Persistent conversion state data.
+       *  @param  __to  Start of output buffer.
+       *  @param  __to_end  End of output buffer.
+       *  @param  __to_next  Returns start of unused output area.
+       *  @return  codecvt_base::result.
+      */
+      result
+      unshift(state_type& __state, extern_type* __to, extern_type* __to_end,
+	      extern_type*& __to_next) const
+      { return this->do_unshift(__state, __to,__to_end,__to_next); }
+
+      /**
+       *  @brief  Convert from external to internal character set.
+       *
+       *  Converts input string of extern_type to output string of
+       *  intern_type.  This is analogous to mbsrtowcs.  It does this by
+       *  calling codecvt::do_in.
+       *
+       *  The source and destination character sets are determined by the
+       *  facet's locale, internal and external types.
+       *
+       *  The characters in [from,from_end) are converted and written to
+       *  [to,to_end).  from_next and to_next are set to point to the
+       *  character following the last successfully converted character,
+       *  respectively.  If the result needed no conversion, from_next and
+       *  to_next are not affected.
+       *
+       *  The @a state argument should be initialized if the input is at the
+       *  beginning and carried from a previous call if continuing
+       *  conversion.  There are no guarantees about how @a state is used.
+       *
+       *  The result returned is a member of codecvt_base::result.  If
+       *  all the input is converted, returns codecvt_base::ok.  If no
+       *  conversion is necessary, returns codecvt_base::noconv.  If
+       *  the input ends early or there is insufficient space in the
+       *  output, returns codecvt_base::partial.  Otherwise the
+       *  conversion failed and codecvt_base::error is returned.
+       *
+       *  @param  __state  Persistent conversion state data.
+       *  @param  __from  Start of input.
+       *  @param  __from_end  End of input.
+       *  @param  __from_next  Returns start of unconverted data.
+       *  @param  __to  Start of output buffer.
+       *  @param  __to_end  End of output buffer.
+       *  @param  __to_next  Returns start of unused output area.
+       *  @return  codecvt_base::result.
+      */
+      result
+      in(state_type& __state, const extern_type* __from,
+	 const extern_type* __from_end, const extern_type*& __from_next,
+	 intern_type* __to, intern_type* __to_end,
+	 intern_type*& __to_next) const
+      {
+	return this->do_in(__state, __from, __from_end, __from_next,
+			   __to, __to_end, __to_next);
+      }
+
+      int
+      encoding() const throw()
+      { return this->do_encoding(); }
+
+      bool
+      always_noconv() const throw()
+      { return this->do_always_noconv(); }
+
+      int
+      length(state_type& __state, const extern_type* __from,
+	     const extern_type* __end, size_t __max) const
+      { return this->do_length(__state, __from, __end, __max); }
+
+      int
+      max_length() const throw()
+      { return this->do_max_length(); }
+
+    protected:
+      explicit
+      __codecvt_abstract_base(size_t __refs = 0) : locale::facet(__refs) { }
+
+      virtual
+      ~__codecvt_abstract_base() { }
+
+      /**
+       *  @brief  Convert from internal to external character set.
+       *
+       *  Converts input string of intern_type to output string of
+       *  extern_type.  This function is a hook for derived classes to change
+       *  the value returned.  @see out for more information.
+      */
+      virtual result
+      do_out(state_type& __state, const intern_type* __from,
+	     const intern_type* __from_end, const intern_type*& __from_next,
+	     extern_type* __to, extern_type* __to_end,
+	     extern_type*& __to_next) const = 0;
+
+      virtual result
+      do_unshift(state_type& __state, extern_type* __to,
+		 extern_type* __to_end, extern_type*& __to_next) const = 0;
+
+      virtual result
+      do_in(state_type& __state, const extern_type* __from,
+	    const extern_type* __from_end, const extern_type*& __from_next,
+	    intern_type* __to, intern_type* __to_end,
+	    intern_type*& __to_next) const = 0;
+
+      virtual int
+      do_encoding() const throw() = 0;
+
+      virtual bool
+      do_always_noconv() const throw() = 0;
+
+      virtual int
+      do_length(state_type&, const extern_type* __from,
+		const extern_type* __end, size_t __max) const = 0;
+
+      virtual int
+      do_max_length() const throw() = 0;
+    };
+
+  /**
+   *  @brief  Primary class template codecvt.
+   *  @ingroup locales
+   *
+   *  NB: Generic, mostly useless implementation.
+   *
+  */
+   template<typename _InternT, typename _ExternT, typename _StateT>
+    class codecvt
+    : public __codecvt_abstract_base<_InternT, _ExternT, _StateT>
+    {
+    public:
+      // Types:
+      typedef codecvt_base::result	result;
+      typedef _InternT			intern_type;
+      typedef _ExternT			extern_type;
+      typedef _StateT			state_type;
+
+    protected:
+      __c_locale			_M_c_locale_codecvt;
+
+    public:
+      static locale::id			id;
+
+      explicit
+      codecvt(size_t __refs = 0)
+      : __codecvt_abstract_base<_InternT, _ExternT, _StateT> (__refs),
+	_M_c_locale_codecvt(0)
+      { }
+
+      explicit
+      codecvt(__c_locale __cloc, size_t __refs = 0);
+
+    protected:
+      virtual
+      ~codecvt() { }
+
+      virtual result
+      do_out(state_type& __state, const intern_type* __from,
+	     const intern_type* __from_end, const intern_type*& __from_next,
+	     extern_type* __to, extern_type* __to_end,
+	     extern_type*& __to_next) const;
+
+      virtual result
+      do_unshift(state_type& __state, extern_type* __to,
+		 extern_type* __to_end, extern_type*& __to_next) const;
+
+      virtual result
+      do_in(state_type& __state, const extern_type* __from,
+	    const extern_type* __from_end, const extern_type*& __from_next,
+	    intern_type* __to, intern_type* __to_end,
+	    intern_type*& __to_next) const;
+
+      virtual int
+      do_encoding() const throw();
+
+      virtual bool
+      do_always_noconv() const throw();
+
+      virtual int
+      do_length(state_type&, const extern_type* __from,
+		const extern_type* __end, size_t __max) const;
+
+      virtual int
+      do_max_length() const throw();
+    };
+
+  template<typename _InternT, typename _ExternT, typename _StateT>
+    locale::id codecvt<_InternT, _ExternT, _StateT>::id;
+
+  /// class codecvt<char, char, mbstate_t> specialization.
+  template<>
+    class codecvt<char, char, mbstate_t>
+    : public __codecvt_abstract_base<char, char, mbstate_t>
+    {
+      friend class messages<char>;
+
+    public:
+      // Types:
+      typedef char			intern_type;
+      typedef char			extern_type;
+      typedef mbstate_t			state_type;
+
+    protected:
+      __c_locale			_M_c_locale_codecvt;
+
+    public:
+      static locale::id id;
+
+      explicit
+      codecvt(size_t __refs = 0);
+
+      explicit
+      codecvt(__c_locale __cloc, size_t __refs = 0);
+
+    protected:
+      virtual
+      ~codecvt();
+
+      virtual result
+      do_out(state_type& __state, const intern_type* __from,
+	     const intern_type* __from_end, const intern_type*& __from_next,
+	     extern_type* __to, extern_type* __to_end,
+	     extern_type*& __to_next) const;
+
+      virtual result
+      do_unshift(state_type& __state, extern_type* __to,
+		 extern_type* __to_end, extern_type*& __to_next) const;
+
+      virtual result
+      do_in(state_type& __state, const extern_type* __from,
+	    const extern_type* __from_end, const extern_type*& __from_next,
+	    intern_type* __to, intern_type* __to_end,
+	    intern_type*& __to_next) const;
+
+      virtual int
+      do_encoding() const throw();
+
+      virtual bool
+      do_always_noconv() const throw();
+
+      virtual int
+      do_length(state_type&, const extern_type* __from,
+		const extern_type* __end, size_t __max) const;
+
+      virtual int
+      do_max_length() const throw();
+  };
+
+#ifdef _GLIBCXX_USE_WCHAR_T
+  /** @brief  Class codecvt<wchar_t, char, mbstate_t> specialization.
+   *
+   *  Converts between narrow and wide characters in the native character set
+   */
+  template<>
+    class codecvt<wchar_t, char, mbstate_t>
+    : public __codecvt_abstract_base<wchar_t, char, mbstate_t>
+    {
+      friend class messages<wchar_t>;
+
+    public:
+      // Types:
+      typedef wchar_t			intern_type;
+      typedef char			extern_type;
+      typedef mbstate_t			state_type;
+
+    protected:
+      __c_locale			_M_c_locale_codecvt;
+
+    public:
+      static locale::id			id;
+
+      explicit
+      codecvt(size_t __refs = 0);
+
+      explicit
+      codecvt(__c_locale __cloc, size_t __refs = 0);
+
+    protected:
+      virtual
+      ~codecvt();
+
+      virtual result
+      do_out(state_type& __state, const intern_type* __from,
+	     const intern_type* __from_end, const intern_type*& __from_next,
+	     extern_type* __to, extern_type* __to_end,
+	     extern_type*& __to_next) const;
+
+      virtual result
+      do_unshift(state_type& __state,
+		 extern_type* __to, extern_type* __to_end,
+		 extern_type*& __to_next) const;
+
+      virtual result
+      do_in(state_type& __state,
+	     const extern_type* __from, const extern_type* __from_end,
+	     const extern_type*& __from_next,
+	     intern_type* __to, intern_type* __to_end,
+	     intern_type*& __to_next) const;
+
+      virtual
+      int do_encoding() const throw();
+
+      virtual
+      bool do_always_noconv() const throw();
+
+      virtual
+      int do_length(state_type&, const extern_type* __from,
+		    const extern_type* __end, size_t __max) const;
+
+      virtual int
+      do_max_length() const throw();
+    };
+#endif //_GLIBCXX_USE_WCHAR_T
+
+#if __cplusplus >= 201103L
+  /** @brief  Class codecvt<char16_t, char, mbstate_t> specialization.
+   *
+   *  Converts between UTF-16 and UTF-8.
+   */
+  template<>
+    class codecvt<char16_t, char, mbstate_t>
+    : public __codecvt_abstract_base<char16_t, char, mbstate_t>
+    {
+    public:
+      // Types:
+      typedef char16_t			intern_type;
+      typedef char			extern_type;
+      typedef mbstate_t			state_type;
+
+    public:
+      static locale::id			id;
+
+      explicit
+      codecvt(size_t __refs = 0)
+      : __codecvt_abstract_base<char16_t, char, mbstate_t>(__refs) { }
+
+    protected:
+      virtual
+      ~codecvt();
+
+      virtual result
+      do_out(state_type& __state, const intern_type* __from,
+	     const intern_type* __from_end, const intern_type*& __from_next,
+	     extern_type* __to, extern_type* __to_end,
+	     extern_type*& __to_next) const;
+
+      virtual result
+      do_unshift(state_type& __state,
+		 extern_type* __to, extern_type* __to_end,
+		 extern_type*& __to_next) const;
+
+      virtual result
+      do_in(state_type& __state,
+	     const extern_type* __from, const extern_type* __from_end,
+	     const extern_type*& __from_next,
+	     intern_type* __to, intern_type* __to_end,
+	     intern_type*& __to_next) const;
+
+      virtual
+      int do_encoding() const throw();
+
+      virtual
+      bool do_always_noconv() const throw();
+
+      virtual
+      int do_length(state_type&, const extern_type* __from,
+		    const extern_type* __end, size_t __max) const;
+
+      virtual int
+      do_max_length() const throw();
+    };
+
+  /** @brief  Class codecvt<char32_t, char, mbstate_t> specialization.
+   *
+   *  Converts between UTF-32 and UTF-8.
+   */
+  template<>
+    class codecvt<char32_t, char, mbstate_t>
+    : public __codecvt_abstract_base<char32_t, char, mbstate_t>
+    {
+    public:
+      // Types:
+      typedef char32_t			intern_type;
+      typedef char			extern_type;
+      typedef mbstate_t			state_type;
+
+    public:
+      static locale::id			id;
+
+      explicit
+      codecvt(size_t __refs = 0)
+      : __codecvt_abstract_base<char32_t, char, mbstate_t>(__refs) { }
+
+    protected:
+      virtual
+      ~codecvt();
+
+      virtual result
+      do_out(state_type& __state, const intern_type* __from,
+	     const intern_type* __from_end, const intern_type*& __from_next,
+	     extern_type* __to, extern_type* __to_end,
+	     extern_type*& __to_next) const;
+
+      virtual result
+      do_unshift(state_type& __state,
+		 extern_type* __to, extern_type* __to_end,
+		 extern_type*& __to_next) const;
+
+      virtual result
+      do_in(state_type& __state,
+	     const extern_type* __from, const extern_type* __from_end,
+	     const extern_type*& __from_next,
+	     intern_type* __to, intern_type* __to_end,
+	     intern_type*& __to_next) const;
+
+      virtual
+      int do_encoding() const throw();
+
+      virtual
+      bool do_always_noconv() const throw();
+
+      virtual
+      int do_length(state_type&, const extern_type* __from,
+		    const extern_type* __end, size_t __max) const;
+
+      virtual int
+      do_max_length() const throw();
+    };
+
+#ifdef _GLIBCXX_USE_CHAR8_T
+  /** @brief  Class codecvt<char16_t, char8_t, mbstate_t> specialization.
+   *
+   *  Converts between UTF-16 and UTF-8.
+   */
+  template<>
+    class codecvt<char16_t, char8_t, mbstate_t>
+    : public __codecvt_abstract_base<char16_t, char8_t, mbstate_t>
+    {
+    public:
+      // Types:
+      typedef char16_t			intern_type;
+      typedef char8_t			extern_type;
+      typedef mbstate_t			state_type;
+
+    public:
+      static locale::id			id;
+
+      explicit
+      codecvt(size_t __refs = 0)
+      : __codecvt_abstract_base<char16_t, char8_t, mbstate_t>(__refs) { }
+
+    protected:
+      virtual
+      ~codecvt();
+
+      virtual result
+      do_out(state_type& __state, const intern_type* __from,
+	     const intern_type* __from_end, const intern_type*& __from_next,
+	     extern_type* __to, extern_type* __to_end,
+	     extern_type*& __to_next) const;
+
+      virtual result
+      do_unshift(state_type& __state,
+		 extern_type* __to, extern_type* __to_end,
+		 extern_type*& __to_next) const;
+
+      virtual result
+      do_in(state_type& __state,
+	     const extern_type* __from, const extern_type* __from_end,
+	     const extern_type*& __from_next,
+	     intern_type* __to, intern_type* __to_end,
+	     intern_type*& __to_next) const;
+
+      virtual
+      int do_encoding() const throw();
+
+      virtual
+      bool do_always_noconv() const throw();
+
+      virtual
+      int do_length(state_type&, const extern_type* __from,
+		    const extern_type* __end, size_t __max) const;
+
+      virtual int
+      do_max_length() const throw();
+    };
+
+  /** @brief  Class codecvt<char32_t, char8_t, mbstate_t> specialization.
+   *
+   *  Converts between UTF-32 and UTF-8.
+   */
+  template<>
+    class codecvt<char32_t, char8_t, mbstate_t>
+    : public __codecvt_abstract_base<char32_t, char8_t, mbstate_t>
+    {
+    public:
+      // Types:
+      typedef char32_t			intern_type;
+      typedef char8_t			extern_type;
+      typedef mbstate_t			state_type;
+
+    public:
+      static locale::id			id;
+
+      explicit
+      codecvt(size_t __refs = 0)
+      : __codecvt_abstract_base<char32_t, char8_t, mbstate_t>(__refs) { }
+
+    protected:
+      virtual
+      ~codecvt();
+
+      virtual result
+      do_out(state_type& __state, const intern_type* __from,
+	     const intern_type* __from_end, const intern_type*& __from_next,
+	     extern_type* __to, extern_type* __to_end,
+	     extern_type*& __to_next) const;
+
+      virtual result
+      do_unshift(state_type& __state,
+		 extern_type* __to, extern_type* __to_end,
+		 extern_type*& __to_next) const;
+
+      virtual result
+      do_in(state_type& __state,
+	     const extern_type* __from, const extern_type* __from_end,
+	     const extern_type*& __from_next,
+	     intern_type* __to, intern_type* __to_end,
+	     intern_type*& __to_next) const;
+
+      virtual
+      int do_encoding() const throw();
+
+      virtual
+      bool do_always_noconv() const throw();
+
+      virtual
+      int do_length(state_type&, const extern_type* __from,
+		    const extern_type* __end, size_t __max) const;
+
+      virtual int
+      do_max_length() const throw();
+    };
+#endif // _GLIBCXX_USE_CHAR8_T
+
+#endif // C++11
+
+  /// class codecvt_byname [22.2.1.6].
+  template<typename _InternT, typename _ExternT, typename _StateT>
+    class codecvt_byname : public codecvt<_InternT, _ExternT, _StateT>
+    {
+    public:
+      explicit
+      codecvt_byname(const char* __s, size_t __refs = 0)
+      : codecvt<_InternT, _ExternT, _StateT>(__refs)
+      {
+	if (__builtin_strcmp(__s, "C") != 0
+	    && __builtin_strcmp(__s, "POSIX") != 0)
+	  {
+	    this->_S_destroy_c_locale(this->_M_c_locale_codecvt);
+	    this->_S_create_c_locale(this->_M_c_locale_codecvt, __s);
+	  }
+      }
+
+#if __cplusplus >= 201103L
+      explicit
+      codecvt_byname(const string& __s, size_t __refs = 0)
+      : codecvt_byname(__s.c_str(), __refs) { }
+#endif
+
+    protected:
+      virtual
+      ~codecvt_byname() { }
+    };
+
+#if __cplusplus >= 201103L
+  template<>
+    class codecvt_byname<char16_t, char, mbstate_t>
+    : public codecvt<char16_t, char, mbstate_t>
+    {
+    public:
+      explicit
+      codecvt_byname(const char*, size_t __refs = 0)
+      : codecvt<char16_t, char, mbstate_t>(__refs) { }
+
+      explicit
+      codecvt_byname(const string& __s, size_t __refs = 0)
+      : codecvt_byname(__s.c_str(), __refs) { }
+
+    protected:
+      virtual
+      ~codecvt_byname() { }
+    };
+
+  template<>
+    class codecvt_byname<char32_t, char, mbstate_t>
+    : public codecvt<char32_t, char, mbstate_t>
+    {
+    public:
+      explicit
+      codecvt_byname(const char*, size_t __refs = 0)
+      : codecvt<char32_t, char, mbstate_t>(__refs) { }
+
+      explicit
+      codecvt_byname(const string& __s, size_t __refs = 0)
+      : codecvt_byname(__s.c_str(), __refs) { }
+
+    protected:
+      virtual
+      ~codecvt_byname() { }
+    };
+
+#if defined(_GLIBCXX_USE_CHAR8_T)
+  template<>
+    class codecvt_byname<char16_t, char8_t, mbstate_t>
+    : public codecvt<char16_t, char8_t, mbstate_t>
+    {
+    public:
+      explicit
+      codecvt_byname(const char*, size_t __refs = 0)
+      : codecvt<char16_t, char8_t, mbstate_t>(__refs) { }
+
+      explicit
+      codecvt_byname(const string& __s, size_t __refs = 0)
+      : codecvt_byname(__s.c_str(), __refs) { }
+
+    protected:
+      virtual
+      ~codecvt_byname() { }
+    };
+
+  template<>
+    class codecvt_byname<char32_t, char8_t, mbstate_t>
+    : public codecvt<char32_t, char8_t, mbstate_t>
+    {
+    public:
+      explicit
+      codecvt_byname(const char*, size_t __refs = 0)
+      : codecvt<char32_t, char8_t, mbstate_t>(__refs) { }
+
+      explicit
+      codecvt_byname(const string& __s, size_t __refs = 0)
+      : codecvt_byname(__s.c_str(), __refs) { }
+
+    protected:
+      virtual
+      ~codecvt_byname() { }
+    };
+#endif
+
+#endif // C++11
+
+  // Inhibit implicit instantiations for required instantiations,
+  // which are defined via explicit instantiations elsewhere.
+#if _GLIBCXX_EXTERN_TEMPLATE
+  extern template class codecvt_byname<char, char, mbstate_t>;
+
+  extern template
+    const codecvt<char, char, mbstate_t>&
+    use_facet<codecvt<char, char, mbstate_t> >(const locale&);
+
+  extern template
+    bool
+    has_facet<codecvt<char, char, mbstate_t> >(const locale&);
+
+#ifdef _GLIBCXX_USE_WCHAR_T
+  extern template class codecvt_byname<wchar_t, char, mbstate_t>;
+
+  extern template
+    const codecvt<wchar_t, char, mbstate_t>&
+    use_facet<codecvt<wchar_t, char, mbstate_t> >(const locale&);
+
+  extern template
+    bool
+    has_facet<codecvt<wchar_t, char, mbstate_t> >(const locale&);
+#endif
+
+#if __cplusplus >= 201103L
+  extern template class codecvt_byname<char16_t, char, mbstate_t>;
+  extern template class codecvt_byname<char32_t, char, mbstate_t>;
+
+#if defined(_GLIBCXX_USE_CHAR8_T)
+  extern template class codecvt_byname<char16_t, char8_t, mbstate_t>;
+  extern template class codecvt_byname<char32_t, char8_t, mbstate_t>;
+#endif
+
+#endif
+
+#endif
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif // _CODECVT_H
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@concept_check.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@concept_check.h
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@@ -0,0 +1,81 @@
+// Concept-checking control -*- C++ -*-
+
+// Copyright (C) 2001-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/concept_check.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{iterator}
+ */
+
+#ifndef _CONCEPT_CHECK_H
+#define _CONCEPT_CHECK_H 1
+
+#pragma GCC system_header
+
+#include <bits/c++config.h>
+
+// All places in libstdc++-v3 where these are used, or /might/ be used, or
+// don't need to be used, or perhaps /should/ be used, are commented with
+// "concept requirements" (and maybe some more text).  So grep like crazy
+// if you're looking for additional places to use these.
+
+// Concept-checking code is off by default unless users turn it on via
+// configure options or editing c++config.h.
+// It is not supported for freestanding implementations.
+
+#if !defined(_GLIBCXX_CONCEPT_CHECKS) || !_GLIBCXX_HOSTED
+
+#define __glibcxx_function_requires(...)
+#define __glibcxx_class_requires(_a,_b)
+#define __glibcxx_class_requires2(_a,_b,_c)
+#define __glibcxx_class_requires3(_a,_b,_c,_d)
+#define __glibcxx_class_requires4(_a,_b,_c,_d,_e)
+
+#else // the checks are on
+
+#include <bits/boost_concept_check.h>
+
+// Note that the obvious and elegant approach of
+//
+//#define glibcxx_function_requires(C) debug::function_requires< debug::C >()
+//
+// won't work due to concept templates with more than one parameter, e.g.,
+// BinaryPredicateConcept.  The preprocessor tries to split things up on
+// the commas in the template argument list.  We can't use an inner pair of
+// parenthesis to hide the commas, because "debug::(Temp<Foo,Bar>)" isn't
+// a valid instantiation pattern.  Thus, we steal a feature from C99.
+
+#define __glibcxx_function_requires(...)                                 \
+            __gnu_cxx::__function_requires< __gnu_cxx::__VA_ARGS__ >();
+#define __glibcxx_class_requires(_a,_C)                                  \
+            _GLIBCXX_CLASS_REQUIRES(_a, __gnu_cxx, _C);
+#define __glibcxx_class_requires2(_a,_b,_C)                              \
+            _GLIBCXX_CLASS_REQUIRES2(_a, _b, __gnu_cxx, _C);
+#define __glibcxx_class_requires3(_a,_b,_c,_C)                           \
+            _GLIBCXX_CLASS_REQUIRES3(_a, _b, _c, __gnu_cxx, _C);
+#define __glibcxx_class_requires4(_a,_b,_c,_d,_C)                        \
+            _GLIBCXX_CLASS_REQUIRES4(_a, _b, _c, _d, __gnu_cxx, _C);
+
+#endif // enable/disable
+
+#endif // _GLIBCXX_CONCEPT_CHECK
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@cpp_type_traits.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@cpp_type_traits.h
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@@ -0,0 +1,569 @@
+// The  -*- C++ -*- type traits classes for internal use in libstdc++
+
+// Copyright (C) 2000-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/cpp_type_traits.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{ext/type_traits}
+ */
+
+// Written by Gabriel Dos Reis <dosreis@cmla.ens-cachan.fr>
+
+#ifndef _CPP_TYPE_TRAITS_H
+#define _CPP_TYPE_TRAITS_H 1
+
+#pragma GCC system_header
+
+#include <bits/c++config.h>
+
+//
+// This file provides some compile-time information about various types.
+// These representations were designed, on purpose, to be constant-expressions
+// and not types as found in <bits/type_traits.h>.  In particular, they
+// can be used in control structures and the optimizer hopefully will do
+// the obvious thing.
+//
+// Why integral expressions, and not functions nor types?
+// Firstly, these compile-time entities are used as template-arguments
+// so function return values won't work:  We need compile-time entities.
+// We're left with types and constant  integral expressions.
+// Secondly, from the point of view of ease of use, type-based compile-time
+// information is -not- *that* convenient.  One has to write lots of
+// overloaded functions and to hope that the compiler will select the right
+// one. As a net effect, the overall structure isn't very clear at first
+// glance.
+// Thirdly, partial ordering and overload resolution (of function templates)
+// is highly costly in terms of compiler-resource.  It is a Good Thing to
+// keep these resource consumption as least as possible.
+//
+// See valarray_array.h for a case use.
+//
+// -- Gaby (dosreis@cmla.ens-cachan.fr) 2000-03-06.
+//
+// Update 2005: types are also provided and <bits/type_traits.h> has been
+// removed.
+//
+
+extern "C++" {
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  struct __true_type { };
+  struct __false_type { };
+
+  template<bool>
+    struct __truth_type
+    { typedef __false_type __type; };
+
+  template<>
+    struct __truth_type<true>
+    { typedef __true_type __type; };
+
+  // N.B. The conversions to bool are needed due to the issue
+  // explained in c++/19404.
+  template<class _Sp, class _Tp>
+    struct __traitor
+    {
+      enum { __value = bool(_Sp::__value) || bool(_Tp::__value) };
+      typedef typename __truth_type<__value>::__type __type;
+    };
+
+  // Compare for equality of types.
+  template<typename, typename>
+    struct __are_same
+    {
+      enum { __value = 0 };
+      typedef __false_type __type;
+    };
+
+  template<typename _Tp>
+    struct __are_same<_Tp, _Tp>
+    {
+      enum { __value = 1 };
+      typedef __true_type __type;
+    };
+
+  // Holds if the template-argument is a void type.
+  template<typename _Tp>
+    struct __is_void
+    {
+      enum { __value = 0 };
+      typedef __false_type __type;
+    };
+
+  template<>
+    struct __is_void<void>
+    {
+      enum { __value = 1 };
+      typedef __true_type __type;
+    };
+
+  //
+  // Integer types
+  //
+  template<typename _Tp>
+    struct __is_integer
+    {
+      enum { __value = 0 };
+      typedef __false_type __type;
+    };
+
+  // Thirteen specializations (yes there are eleven standard integer
+  // types; <em>long long</em> and <em>unsigned long long</em> are
+  // supported as extensions).  Up to four target-specific __int<N>
+  // types are supported as well.
+  template<>
+    struct __is_integer<bool>
+    {
+      enum { __value = 1 };
+      typedef __true_type __type;
+    };
+
+  template<>
+    struct __is_integer<char>
+    {
+      enum { __value = 1 };
+      typedef __true_type __type;
+    };
+
+  template<>
+    struct __is_integer<signed char>
+    {
+      enum { __value = 1 };
+      typedef __true_type __type;
+    };
+
+  template<>
+    struct __is_integer<unsigned char>
+    {
+      enum { __value = 1 };
+      typedef __true_type __type;
+    };
+
+# ifdef __WCHAR_TYPE__
+  template<>
+    struct __is_integer<wchar_t>
+    {
+      enum { __value = 1 };
+      typedef __true_type __type;
+    };
+# endif
+
+#ifdef _GLIBCXX_USE_CHAR8_T
+  template<>
+    struct __is_integer<char8_t>
+    {
+      enum { __value = 1 };
+      typedef __true_type __type;
+    };
+#endif
+
+#if __cplusplus >= 201103L
+  template<>
+    struct __is_integer<char16_t>
+    {
+      enum { __value = 1 };
+      typedef __true_type __type;
+    };
+
+  template<>
+    struct __is_integer<char32_t>
+    {
+      enum { __value = 1 };
+      typedef __true_type __type;
+    };
+#endif
+
+  template<>
+    struct __is_integer<short>
+    {
+      enum { __value = 1 };
+      typedef __true_type __type;
+    };
+
+  template<>
+    struct __is_integer<unsigned short>
+    {
+      enum { __value = 1 };
+      typedef __true_type __type;
+    };
+
+  template<>
+    struct __is_integer<int>
+    {
+      enum { __value = 1 };
+      typedef __true_type __type;
+    };
+
+  template<>
+    struct __is_integer<unsigned int>
+    {
+      enum { __value = 1 };
+      typedef __true_type __type;
+    };
+
+  template<>
+    struct __is_integer<long>
+    {
+      enum { __value = 1 };
+      typedef __true_type __type;
+    };
+
+  template<>
+    struct __is_integer<unsigned long>
+    {
+      enum { __value = 1 };
+      typedef __true_type __type;
+    };
+
+  template<>
+    struct __is_integer<long long>
+    {
+      enum { __value = 1 };
+      typedef __true_type __type;
+    };
+
+  template<>
+    struct __is_integer<unsigned long long>
+    {
+      enum { __value = 1 };
+      typedef __true_type __type;
+    };
+
+#define __INT_N(TYPE) 			\
+  __extension__				\
+  template<>				\
+    struct __is_integer<TYPE>		\
+    {					\
+      enum { __value = 1 };		\
+      typedef __true_type __type;	\
+    };					\
+  __extension__				\
+  template<>				\
+    struct __is_integer<unsigned TYPE>	\
+    {					\
+      enum { __value = 1 };		\
+      typedef __true_type __type;	\
+    };
+
+#ifdef __GLIBCXX_TYPE_INT_N_0
+__INT_N(__GLIBCXX_TYPE_INT_N_0)
+#endif
+#ifdef __GLIBCXX_TYPE_INT_N_1
+__INT_N(__GLIBCXX_TYPE_INT_N_1)
+#endif
+#ifdef __GLIBCXX_TYPE_INT_N_2
+__INT_N(__GLIBCXX_TYPE_INT_N_2)
+#endif
+#ifdef __GLIBCXX_TYPE_INT_N_3
+__INT_N(__GLIBCXX_TYPE_INT_N_3)
+#endif
+
+#undef __INT_N
+
+  //
+  // Floating point types
+  //
+  template<typename _Tp>
+    struct __is_floating
+    {
+      enum { __value = 0 };
+      typedef __false_type __type;
+    };
+
+  // three specializations (float, double and 'long double')
+  template<>
+    struct __is_floating<float>
+    {
+      enum { __value = 1 };
+      typedef __true_type __type;
+    };
+
+  template<>
+    struct __is_floating<double>
+    {
+      enum { __value = 1 };
+      typedef __true_type __type;
+    };
+
+  template<>
+    struct __is_floating<long double>
+    {
+      enum { __value = 1 };
+      typedef __true_type __type;
+    };
+
+  //
+  // Pointer types
+  //
+  template<typename _Tp>
+    struct __is_pointer
+    {
+      enum { __value = 0 };
+      typedef __false_type __type;
+    };
+
+  template<typename _Tp>
+    struct __is_pointer<_Tp*>
+    {
+      enum { __value = 1 };
+      typedef __true_type __type;
+    };
+
+  //
+  // An arithmetic type is an integer type or a floating point type
+  //
+  template<typename _Tp>
+    struct __is_arithmetic
+    : public __traitor<__is_integer<_Tp>, __is_floating<_Tp> >
+    { };
+
+  //
+  // A scalar type is an arithmetic type or a pointer type
+  // 
+  template<typename _Tp>
+    struct __is_scalar
+    : public __traitor<__is_arithmetic<_Tp>, __is_pointer<_Tp> >
+    { };
+
+  //
+  // For use in std::copy and std::find overloads for streambuf iterators.
+  //
+  template<typename _Tp>
+    struct __is_char
+    {
+      enum { __value = 0 };
+      typedef __false_type __type;
+    };
+
+  template<>
+    struct __is_char<char>
+    {
+      enum { __value = 1 };
+      typedef __true_type __type;
+    };
+
+#ifdef __WCHAR_TYPE__
+  template<>
+    struct __is_char<wchar_t>
+    {
+      enum { __value = 1 };
+      typedef __true_type __type;
+    };
+#endif
+
+  template<typename _Tp>
+    struct __is_byte
+    {
+      enum { __value = 0 };
+      typedef __false_type __type;
+    };
+
+  template<>
+    struct __is_byte<char>
+    {
+      enum { __value = 1 };
+      typedef __true_type __type;
+    };
+
+  template<>
+    struct __is_byte<signed char>
+    {
+      enum { __value = 1 };
+      typedef __true_type __type;
+    };
+
+  template<>
+    struct __is_byte<unsigned char>
+    {
+      enum { __value = 1 };
+      typedef __true_type __type;
+    };
+
+#if __cplusplus >= 201703L
+  enum class byte : unsigned char;
+
+  template<>
+    struct __is_byte<byte>
+    {
+      enum { __value = 1 };
+      typedef __true_type __type;
+    };
+#endif // C++17
+
+#ifdef _GLIBCXX_USE_CHAR8_T
+  template<>
+    struct __is_byte<char8_t>
+    {
+      enum { __value = 1 };
+      typedef __true_type __type;
+    };
+#endif
+
+  template<typename> struct iterator_traits;
+
+  // A type that is safe for use with memcpy, memmove, memcmp etc.
+  template<typename _Tp>
+    struct __is_nonvolatile_trivially_copyable
+    {
+      enum { __value = __is_trivially_copyable(_Tp) };
+    };
+
+  // Cannot use memcpy/memmove/memcmp on volatile types even if they are
+  // trivially copyable, so ensure __memcpyable<volatile int*, volatile int*>
+  // and similar will be false.
+  template<typename _Tp>
+    struct __is_nonvolatile_trivially_copyable<volatile _Tp>
+    {
+      enum { __value = 0 };
+    };
+
+  // Whether two iterator types can be used with memcpy/memmove.
+  template<typename _OutputIter, typename _InputIter>
+    struct __memcpyable
+    {
+      enum { __value = 0 };
+    };
+
+  template<typename _Tp>
+    struct __memcpyable<_Tp*, _Tp*>
+    : __is_nonvolatile_trivially_copyable<_Tp>
+    { };
+
+  template<typename _Tp>
+    struct __memcpyable<_Tp*, const _Tp*>
+    : __is_nonvolatile_trivially_copyable<_Tp>
+    { };
+
+  // Whether two iterator types can be used with memcmp.
+  // This trait only says it's well-formed to use memcmp, not that it
+  // gives the right answer for a given algorithm. So for example, std::equal
+  // needs to add additional checks that the types are integers or pointers,
+  // because other trivially copyable types can overload operator==.
+  template<typename _Iter1, typename _Iter2>
+    struct __memcmpable
+    {
+      enum { __value = 0 };
+    };
+
+  // OK to use memcmp with pointers to trivially copyable types.
+  template<typename _Tp>
+    struct __memcmpable<_Tp*, _Tp*>
+    : __is_nonvolatile_trivially_copyable<_Tp>
+    { };
+
+  template<typename _Tp>
+    struct __memcmpable<const _Tp*, _Tp*>
+    : __is_nonvolatile_trivially_copyable<_Tp>
+    { };
+
+  template<typename _Tp>
+    struct __memcmpable<_Tp*, const _Tp*>
+    : __is_nonvolatile_trivially_copyable<_Tp>
+    { };
+
+  // Whether memcmp can be used to determine ordering for a type
+  // e.g. in std::lexicographical_compare or three-way comparisons.
+  // True for unsigned integer-like types where comparing each byte in turn
+  // as an unsigned char yields the right result. This is true for all
+  // unsigned integers on big endian targets, but only unsigned narrow
+  // character types (and std::byte) on little endian targets.
+  template<typename _Tp, bool _TreatAsBytes =
+#if __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+	__is_integer<_Tp>::__value
+#else
+	__is_byte<_Tp>::__value
+#endif
+    >
+    struct __is_memcmp_ordered
+    {
+      static const bool __value = _Tp(-1) > _Tp(1); // is unsigned
+    };
+
+  template<typename _Tp>
+    struct __is_memcmp_ordered<_Tp, false>
+    {
+      static const bool __value = false;
+    };
+
+  // Whether two types can be compared using memcmp.
+  template<typename _Tp, typename _Up, bool = sizeof(_Tp) == sizeof(_Up)>
+    struct __is_memcmp_ordered_with
+    {
+      static const bool __value = __is_memcmp_ordered<_Tp>::__value
+	&& __is_memcmp_ordered<_Up>::__value;
+    };
+
+  template<typename _Tp, typename _Up>
+    struct __is_memcmp_ordered_with<_Tp, _Up, false>
+    {
+      static const bool __value = false;
+    };
+
+#if __cplusplus >= 201703L
+#if __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+  // std::byte is not an integer, but it can be compared using memcmp.
+  template<>
+    struct __is_memcmp_ordered<std::byte, false>
+    { static constexpr bool __value = true; };
+#endif
+
+  // std::byte can only be compared to itself, not to other types.
+  template<>
+    struct __is_memcmp_ordered_with<std::byte, std::byte, true>
+    { static constexpr bool __value = true; };
+
+  template<typename _Tp, bool _SameSize>
+    struct __is_memcmp_ordered_with<_Tp, std::byte, _SameSize>
+    { static constexpr bool __value = false; };
+
+  template<typename _Up, bool _SameSize>
+    struct __is_memcmp_ordered_with<std::byte, _Up, _SameSize>
+    { static constexpr bool __value = false; };
+#endif
+
+  //
+  // Move iterator type
+  //
+  template<typename _Tp>
+    struct __is_move_iterator
+    {
+      enum { __value = 0 };
+      typedef __false_type __type;
+    };
+
+  // Fallback implementation of the function in bits/stl_iterator.h used to
+  // remove the move_iterator wrapper.
+  template<typename _Iterator>
+    _GLIBCXX20_CONSTEXPR
+    inline _Iterator
+    __miter_base(_Iterator __it)
+    { return __it; }
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+} // extern "C++"
+
+#endif //_CPP_TYPE_TRAITS_H
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@cxxabi_forced.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@cxxabi_forced.h
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@cxxabi_forced.h
@@ -0,0 +1,60 @@
+// cxxabi.h subset for cancellation -*- C++ -*-
+  
+// Copyright (C) 2007-2022 Free Software Foundation, Inc.
+//
+// This file is part of GCC.
+//
+// GCC is free software; you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation; either version 3, or (at your option)
+// any later version.
+// 
+// GCC is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+// 
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/cxxabi_forced.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{cxxabi.h}
+ */
+
+#ifndef _CXXABI_FORCED_H
+#define _CXXABI_FORCED_H 1
+
+#pragma GCC system_header
+
+#pragma GCC visibility push(default)
+
+#ifdef __cplusplus
+namespace __cxxabiv1
+{  
+  /** 
+   *  @brief Thrown as part of forced unwinding.
+   *  @ingroup exceptions
+   *
+   *  A magic placeholder class that can be caught by reference to
+   *  recognize forced unwinding.
+   */
+  class __forced_unwind
+  {
+    virtual ~__forced_unwind() throw();
+
+    // Prevent catch by value.
+    virtual void __pure_dummy() = 0; 
+  };
+}
+#endif // __cplusplus
+
+#pragma GCC visibility pop
+
+#endif // __CXXABI_FORCED_H 
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@cxxabi_init_exception.h
@@ -0,0 +1,80 @@
+// ABI Support -*- C++ -*-
+
+// Copyright (C) 2016-2022 Free Software Foundation, Inc.
+//
+// This file is part of GCC.
+//
+// GCC is free software; you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation; either version 3, or (at your option)
+// any later version.
+//
+// GCC is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/cxxabi_init_exception.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly.
+ */
+
+#ifndef _CXXABI_INIT_EXCEPTION_H
+#define _CXXABI_INIT_EXCEPTION_H 1
+
+#pragma GCC system_header
+
+#pragma GCC visibility push(default)
+
+#include <stddef.h>
+#include <bits/c++config.h>
+
+#ifndef _GLIBCXX_CDTOR_CALLABI
+#define _GLIBCXX_CDTOR_CALLABI
+#define _GLIBCXX_HAVE_CDTOR_CALLABI 0
+#else
+#define _GLIBCXX_HAVE_CDTOR_CALLABI 1
+#endif
+
+#ifdef __cplusplus
+
+namespace std
+{
+  class type_info;
+}
+
+namespace __cxxabiv1
+{
+  struct __cxa_refcounted_exception;
+
+  extern "C"
+    {
+      // Allocate memory for the primary exception plus the thrown object.
+      void*
+      __cxa_allocate_exception(size_t) _GLIBCXX_NOTHROW;
+
+      void
+      __cxa_free_exception(void*) _GLIBCXX_NOTHROW;
+
+      // Initialize exception (this is a GNU extension)
+      __cxa_refcounted_exception*
+      __cxa_init_primary_exception(void *object, std::type_info *tinfo,
+                void (_GLIBCXX_CDTOR_CALLABI *dest) (void *)) _GLIBCXX_NOTHROW;
+
+    }
+} // namespace __cxxabiv1
+
+#endif
+
+#pragma GCC visibility pop
+
+#endif // _CXXABI_INIT_EXCEPTION_H
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@@ -0,0 +1,1369 @@
+// Deque implementation (out of line) -*- C++ -*-
+
+// Copyright (C) 2001-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/*
+ *
+ * Copyright (c) 1994
+ * Hewlett-Packard Company
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Hewlett-Packard Company makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ *
+ *
+ * Copyright (c) 1997
+ * Silicon Graphics Computer Systems, Inc.
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Silicon Graphics makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ */
+
+/** @file bits/deque.tcc
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{deque}
+ */
+
+#ifndef _DEQUE_TCC
+#define _DEQUE_TCC 1
+
+#include <bits/stl_algobase.h>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+_GLIBCXX_BEGIN_NAMESPACE_CONTAINER
+
+#if __cplusplus >= 201103L
+  template <typename _Tp, typename _Alloc>
+    void
+    deque<_Tp, _Alloc>::
+    _M_default_initialize()
+    {
+      _Map_pointer __cur;
+      __try
+	{
+	  for (__cur = this->_M_impl._M_start._M_node;
+	       __cur < this->_M_impl._M_finish._M_node;
+	       ++__cur)
+	    std::__uninitialized_default_a(*__cur, *__cur + _S_buffer_size(),
+					   _M_get_Tp_allocator());
+	  std::__uninitialized_default_a(this->_M_impl._M_finish._M_first,
+					 this->_M_impl._M_finish._M_cur,
+					 _M_get_Tp_allocator());
+	}
+      __catch(...)
+	{
+	  std::_Destroy(this->_M_impl._M_start, iterator(*__cur, __cur),
+			_M_get_Tp_allocator());
+	  __throw_exception_again;
+	}
+    }
+#endif
+
+  template <typename _Tp, typename _Alloc>
+    deque<_Tp, _Alloc>&
+    deque<_Tp, _Alloc>::
+    operator=(const deque& __x)
+    {
+      if (std::__addressof(__x) != this)
+	{
+#if __cplusplus >= 201103L
+	  if (_Alloc_traits::_S_propagate_on_copy_assign())
+	    {
+	      if (!_Alloc_traits::_S_always_equal()
+		  && _M_get_Tp_allocator() != __x._M_get_Tp_allocator())
+		{
+		  // Replacement allocator cannot free existing storage,
+		  // so deallocate everything and take copy of __x's data.
+		  _M_replace_map(__x, __x.get_allocator());
+		  std::__alloc_on_copy(_M_get_Tp_allocator(),
+				       __x._M_get_Tp_allocator());
+		  return *this;
+		}
+	      std::__alloc_on_copy(_M_get_Tp_allocator(),
+				   __x._M_get_Tp_allocator());
+	    }
+#endif
+	  const size_type __len = size();
+	  if (__len >= __x.size())
+	    _M_erase_at_end(std::copy(__x.begin(), __x.end(),
+				      this->_M_impl._M_start));
+	  else
+	    {
+	      const_iterator __mid = __x.begin() + difference_type(__len);
+	      std::copy(__x.begin(), __mid, this->_M_impl._M_start);
+	      _M_range_insert_aux(this->_M_impl._M_finish, __mid, __x.end(),
+				  std::random_access_iterator_tag());
+	    }
+	}
+      return *this;
+    }
+
+#if __cplusplus >= 201103L
+  template<typename _Tp, typename _Alloc>
+    template<typename... _Args>
+#if __cplusplus > 201402L
+      typename deque<_Tp, _Alloc>::reference
+#else
+      void
+#endif
+      deque<_Tp, _Alloc>::
+      emplace_front(_Args&&... __args)
+      {
+	if (this->_M_impl._M_start._M_cur != this->_M_impl._M_start._M_first)
+	  {
+	    _Alloc_traits::construct(this->_M_impl,
+				     this->_M_impl._M_start._M_cur - 1,
+				     std::forward<_Args>(__args)...);
+	    --this->_M_impl._M_start._M_cur;
+	  }
+	else
+	  _M_push_front_aux(std::forward<_Args>(__args)...);
+#if __cplusplus > 201402L
+	return front();
+#endif
+      }
+
+  template<typename _Tp, typename _Alloc>
+    template<typename... _Args>
+#if __cplusplus > 201402L
+      typename deque<_Tp, _Alloc>::reference
+#else
+      void
+#endif
+      deque<_Tp, _Alloc>::
+      emplace_back(_Args&&... __args)
+      {
+	if (this->_M_impl._M_finish._M_cur
+	    != this->_M_impl._M_finish._M_last - 1)
+	  {
+	    _Alloc_traits::construct(this->_M_impl,
+				     this->_M_impl._M_finish._M_cur,
+				     std::forward<_Args>(__args)...);
+	    ++this->_M_impl._M_finish._M_cur;
+	  }
+	else
+	  _M_push_back_aux(std::forward<_Args>(__args)...);
+#if __cplusplus > 201402L
+	return back();
+#endif
+      }
+#endif
+
+#if __cplusplus >= 201103L
+  template<typename _Tp, typename _Alloc>
+    template<typename... _Args>
+      typename deque<_Tp, _Alloc>::iterator
+      deque<_Tp, _Alloc>::
+      emplace(const_iterator __position, _Args&&... __args)
+      {
+	if (__position._M_cur == this->_M_impl._M_start._M_cur)
+	  {
+	    emplace_front(std::forward<_Args>(__args)...);
+	    return this->_M_impl._M_start;
+	  }
+	else if (__position._M_cur == this->_M_impl._M_finish._M_cur)
+	  {
+	    emplace_back(std::forward<_Args>(__args)...);
+	    iterator __tmp = this->_M_impl._M_finish;
+	    --__tmp;
+	    return __tmp;
+	  }
+	else
+	  return _M_insert_aux(__position._M_const_cast(),
+			       std::forward<_Args>(__args)...);
+      }
+#endif
+
+  template <typename _Tp, typename _Alloc>
+    typename deque<_Tp, _Alloc>::iterator
+    deque<_Tp, _Alloc>::
+#if __cplusplus >= 201103L
+    insert(const_iterator __position, const value_type& __x)
+#else
+    insert(iterator __position, const value_type& __x)
+#endif
+    {
+      if (__position._M_cur == this->_M_impl._M_start._M_cur)
+	{
+	  push_front(__x);
+	  return this->_M_impl._M_start;
+	}
+      else if (__position._M_cur == this->_M_impl._M_finish._M_cur)
+	{
+	  push_back(__x);
+	  iterator __tmp = this->_M_impl._M_finish;
+	  --__tmp;
+	  return __tmp;
+	}
+      else
+	return _M_insert_aux(__position._M_const_cast(), __x);
+   }
+
+  template <typename _Tp, typename _Alloc>
+    typename deque<_Tp, _Alloc>::iterator
+    deque<_Tp, _Alloc>::
+    _M_erase(iterator __position)
+    {
+      iterator __next = __position;
+      ++__next;
+      const difference_type __index = __position - begin();
+      if (static_cast<size_type>(__index) < (size() >> 1))
+	{
+	  if (__position != begin())
+	    _GLIBCXX_MOVE_BACKWARD3(begin(), __position, __next);
+	  pop_front();
+	}
+      else
+	{
+	  if (__next != end())
+	    _GLIBCXX_MOVE3(__next, end(), __position);
+	  pop_back();
+	}
+      return begin() + __index;
+    }
+
+  template <typename _Tp, typename _Alloc>
+    typename deque<_Tp, _Alloc>::iterator
+    deque<_Tp, _Alloc>::
+    _M_erase(iterator __first, iterator __last)
+    {
+      if (__first == __last)
+	return __first;
+      else if (__first == begin() && __last == end())
+	{
+	  clear();
+	  return end();
+	}
+      else
+	{
+	  const difference_type __n = __last - __first;
+	  const difference_type __elems_before = __first - begin();
+	  if (static_cast<size_type>(__elems_before) <= (size() - __n) / 2)
+	    {
+	      if (__first != begin())
+		_GLIBCXX_MOVE_BACKWARD3(begin(), __first, __last);
+	      _M_erase_at_begin(begin() + __n);
+	    }
+	  else
+	    {
+	      if (__last != end())
+		_GLIBCXX_MOVE3(__last, end(), __first);
+	      _M_erase_at_end(end() - __n);
+	    }
+	  return begin() + __elems_before;
+	}
+    }
+
+  template <typename _Tp, class _Alloc>
+    template <typename _InputIterator>
+      void
+      deque<_Tp, _Alloc>::
+      _M_assign_aux(_InputIterator __first, _InputIterator __last,
+		    std::input_iterator_tag)
+      {
+	iterator __cur = begin();
+	for (; __first != __last && __cur != end(); ++__cur, (void)++__first)
+	  *__cur = *__first;
+	if (__first == __last)
+	  _M_erase_at_end(__cur);
+	else
+	  _M_range_insert_aux(end(), __first, __last,
+			      std::__iterator_category(__first));
+      }
+
+  template <typename _Tp, typename _Alloc>
+    void
+    deque<_Tp, _Alloc>::
+    _M_fill_insert(iterator __pos, size_type __n, const value_type& __x)
+    {
+      if (__pos._M_cur == this->_M_impl._M_start._M_cur)
+	{
+	  iterator __new_start = _M_reserve_elements_at_front(__n);
+	  __try
+	    {
+	      std::__uninitialized_fill_a(__new_start, this->_M_impl._M_start,
+					  __x, _M_get_Tp_allocator());
+	      this->_M_impl._M_start = __new_start;
+	    }
+	  __catch(...)
+	    {
+	      _M_destroy_nodes(__new_start._M_node,
+			       this->_M_impl._M_start._M_node);
+	      __throw_exception_again;
+	    }
+	}
+      else if (__pos._M_cur == this->_M_impl._M_finish._M_cur)
+	{
+	  iterator __new_finish = _M_reserve_elements_at_back(__n);
+	  __try
+	    {
+	      std::__uninitialized_fill_a(this->_M_impl._M_finish,
+					  __new_finish, __x,
+					  _M_get_Tp_allocator());
+	      this->_M_impl._M_finish = __new_finish;
+	    }
+	  __catch(...)
+	    {
+	      _M_destroy_nodes(this->_M_impl._M_finish._M_node + 1,
+			       __new_finish._M_node + 1);
+	      __throw_exception_again;
+	    }
+	}
+      else
+	_M_insert_aux(__pos, __n, __x);
+    }
+
+#if __cplusplus >= 201103L
+  template <typename _Tp, typename _Alloc>
+    void
+    deque<_Tp, _Alloc>::
+    _M_default_append(size_type __n)
+    {
+      if (__n)
+	{
+	  iterator __new_finish = _M_reserve_elements_at_back(__n);
+	  __try
+	    {
+	      std::__uninitialized_default_a(this->_M_impl._M_finish,
+					     __new_finish,
+					     _M_get_Tp_allocator());
+	      this->_M_impl._M_finish = __new_finish;
+	    }
+	  __catch(...)
+	    {
+	      _M_destroy_nodes(this->_M_impl._M_finish._M_node + 1,
+			       __new_finish._M_node + 1);
+	      __throw_exception_again;
+	    }
+	}
+    }
+
+  template <typename _Tp, typename _Alloc>
+    bool
+    deque<_Tp, _Alloc>::
+    _M_shrink_to_fit()
+    {
+      const difference_type __front_capacity
+	= (this->_M_impl._M_start._M_cur - this->_M_impl._M_start._M_first);
+      if (__front_capacity == 0)
+	return false;
+
+      const difference_type __back_capacity
+	= (this->_M_impl._M_finish._M_last - this->_M_impl._M_finish._M_cur);
+      if (__front_capacity + __back_capacity < _S_buffer_size())
+	return false;
+
+      return std::__shrink_to_fit_aux<deque>::_S_do_it(*this);
+    }
+#endif
+
+  template <typename _Tp, typename _Alloc>
+    void
+    deque<_Tp, _Alloc>::
+    _M_fill_initialize(const value_type& __value)
+    {
+      _Map_pointer __cur;
+      __try
+	{
+	  for (__cur = this->_M_impl._M_start._M_node;
+	       __cur < this->_M_impl._M_finish._M_node;
+	       ++__cur)
+	    std::__uninitialized_fill_a(*__cur, *__cur + _S_buffer_size(),
+					__value, _M_get_Tp_allocator());
+	  std::__uninitialized_fill_a(this->_M_impl._M_finish._M_first,
+				      this->_M_impl._M_finish._M_cur,
+				      __value, _M_get_Tp_allocator());
+	}
+      __catch(...)
+	{
+	  std::_Destroy(this->_M_impl._M_start, iterator(*__cur, __cur),
+			_M_get_Tp_allocator());
+	  __throw_exception_again;
+	}
+    }
+
+  template <typename _Tp, typename _Alloc>
+    template <typename _InputIterator>
+      void
+      deque<_Tp, _Alloc>::
+      _M_range_initialize(_InputIterator __first, _InputIterator __last,
+			  std::input_iterator_tag)
+      {
+	this->_M_initialize_map(0);
+	__try
+	  {
+	    for (; __first != __last; ++__first)
+#if __cplusplus >= 201103L
+	      emplace_back(*__first);
+#else
+	      push_back(*__first);
+#endif
+	  }
+	__catch(...)
+	  {
+	    clear();
+	    __throw_exception_again;
+	  }
+      }
+
+  template <typename _Tp, typename _Alloc>
+    template <typename _ForwardIterator>
+      void
+      deque<_Tp, _Alloc>::
+      _M_range_initialize(_ForwardIterator __first, _ForwardIterator __last,
+			  std::forward_iterator_tag)
+      {
+	const size_type __n = std::distance(__first, __last);
+	this->_M_initialize_map(_S_check_init_len(__n, _M_get_Tp_allocator()));
+
+	_Map_pointer __cur_node;
+	__try
+	  {
+	    for (__cur_node = this->_M_impl._M_start._M_node;
+		 __cur_node < this->_M_impl._M_finish._M_node;
+		 ++__cur_node)
+	      {
+		if (__n < _S_buffer_size())
+		  __builtin_unreachable(); // See PR 100516
+
+		_ForwardIterator __mid = __first;
+		std::advance(__mid, _S_buffer_size());
+		std::__uninitialized_copy_a(__first, __mid, *__cur_node,
+					    _M_get_Tp_allocator());
+		__first = __mid;
+	      }
+	    std::__uninitialized_copy_a(__first, __last,
+					this->_M_impl._M_finish._M_first,
+					_M_get_Tp_allocator());
+	  }
+	__catch(...)
+	  {
+	    std::_Destroy(this->_M_impl._M_start,
+			  iterator(*__cur_node, __cur_node),
+			  _M_get_Tp_allocator());
+	    __throw_exception_again;
+	  }
+      }
+
+  // Called only if _M_impl._M_finish._M_cur == _M_impl._M_finish._M_last - 1.
+  template<typename _Tp, typename _Alloc>
+#if __cplusplus >= 201103L
+    template<typename... _Args>
+      void
+      deque<_Tp, _Alloc>::
+      _M_push_back_aux(_Args&&... __args)
+#else
+      void
+      deque<_Tp, _Alloc>::
+      _M_push_back_aux(const value_type& __t)
+#endif
+      {
+	if (size() == max_size())
+	  __throw_length_error(
+	      __N("cannot create std::deque larger than max_size()"));
+
+	_M_reserve_map_at_back();
+	*(this->_M_impl._M_finish._M_node + 1) = this->_M_allocate_node();
+	__try
+	  {
+#if __cplusplus >= 201103L
+	    _Alloc_traits::construct(this->_M_impl,
+				     this->_M_impl._M_finish._M_cur,
+				     std::forward<_Args>(__args)...);
+#else
+	    this->_M_impl.construct(this->_M_impl._M_finish._M_cur, __t);
+#endif
+	    this->_M_impl._M_finish._M_set_node(this->_M_impl._M_finish._M_node
+						+ 1);
+	    this->_M_impl._M_finish._M_cur = this->_M_impl._M_finish._M_first;
+	  }
+	__catch(...)
+	  {
+	    _M_deallocate_node(*(this->_M_impl._M_finish._M_node + 1));
+	    __throw_exception_again;
+	  }
+      }
+
+  // Called only if _M_impl._M_start._M_cur == _M_impl._M_start._M_first.
+  template<typename _Tp, typename _Alloc>
+#if __cplusplus >= 201103L
+    template<typename... _Args>
+      void
+      deque<_Tp, _Alloc>::
+      _M_push_front_aux(_Args&&... __args)
+#else
+      void
+      deque<_Tp, _Alloc>::
+      _M_push_front_aux(const value_type& __t)
+#endif
+      {
+	if (size() == max_size())
+	  __throw_length_error(
+	      __N("cannot create std::deque larger than max_size()"));
+
+	_M_reserve_map_at_front();
+	*(this->_M_impl._M_start._M_node - 1) = this->_M_allocate_node();
+	__try
+	  {
+	    this->_M_impl._M_start._M_set_node(this->_M_impl._M_start._M_node
+					       - 1);
+	    this->_M_impl._M_start._M_cur = this->_M_impl._M_start._M_last - 1;
+#if __cplusplus >= 201103L
+	    _Alloc_traits::construct(this->_M_impl,
+				     this->_M_impl._M_start._M_cur,
+				     std::forward<_Args>(__args)...);
+#else
+	    this->_M_impl.construct(this->_M_impl._M_start._M_cur, __t);
+#endif
+	  }
+	__catch(...)
+	  {
+	    ++this->_M_impl._M_start;
+	    _M_deallocate_node(*(this->_M_impl._M_start._M_node - 1));
+	    __throw_exception_again;
+	  }
+      }
+
+  // Called only if _M_impl._M_finish._M_cur == _M_impl._M_finish._M_first.
+  template <typename _Tp, typename _Alloc>
+    void deque<_Tp, _Alloc>::
+    _M_pop_back_aux()
+    {
+      _M_deallocate_node(this->_M_impl._M_finish._M_first);
+      this->_M_impl._M_finish._M_set_node(this->_M_impl._M_finish._M_node - 1);
+      this->_M_impl._M_finish._M_cur = this->_M_impl._M_finish._M_last - 1;
+      _Alloc_traits::destroy(_M_get_Tp_allocator(),
+			     this->_M_impl._M_finish._M_cur);
+    }
+
+  // Called only if _M_impl._M_start._M_cur == _M_impl._M_start._M_last - 1.
+  // Note that if the deque has at least one element (a precondition for this
+  // member function), and if
+  //   _M_impl._M_start._M_cur == _M_impl._M_start._M_last,
+  // then the deque must have at least two nodes.
+  template <typename _Tp, typename _Alloc>
+    void deque<_Tp, _Alloc>::
+    _M_pop_front_aux()
+    {
+      _Alloc_traits::destroy(_M_get_Tp_allocator(),
+			     this->_M_impl._M_start._M_cur);
+      _M_deallocate_node(this->_M_impl._M_start._M_first);
+      this->_M_impl._M_start._M_set_node(this->_M_impl._M_start._M_node + 1);
+      this->_M_impl._M_start._M_cur = this->_M_impl._M_start._M_first;
+    }
+
+  template <typename _Tp, typename _Alloc>
+    template <typename _InputIterator>
+      void
+      deque<_Tp, _Alloc>::
+      _M_range_insert_aux(iterator __pos,
+			  _InputIterator __first, _InputIterator __last,
+			  std::input_iterator_tag)
+      { std::copy(__first, __last, std::inserter(*this, __pos)); }
+
+  template <typename _Tp, typename _Alloc>
+    template <typename _ForwardIterator>
+      void
+      deque<_Tp, _Alloc>::
+      _M_range_insert_aux(iterator __pos,
+			  _ForwardIterator __first, _ForwardIterator __last,
+			  std::forward_iterator_tag)
+      {
+	const size_type __n = std::distance(__first, __last);
+	if (__pos._M_cur == this->_M_impl._M_start._M_cur)
+	  {
+	    iterator __new_start = _M_reserve_elements_at_front(__n);
+	    __try
+	      {
+		std::__uninitialized_copy_a(__first, __last, __new_start,
+					    _M_get_Tp_allocator());
+		this->_M_impl._M_start = __new_start;
+	      }
+	    __catch(...)
+	      {
+		_M_destroy_nodes(__new_start._M_node,
+				 this->_M_impl._M_start._M_node);
+		__throw_exception_again;
+	      }
+	  }
+	else if (__pos._M_cur == this->_M_impl._M_finish._M_cur)
+	  {
+	    iterator __new_finish = _M_reserve_elements_at_back(__n);
+	    __try
+	      {
+		std::__uninitialized_copy_a(__first, __last,
+					    this->_M_impl._M_finish,
+					    _M_get_Tp_allocator());
+		this->_M_impl._M_finish = __new_finish;
+	      }
+	    __catch(...)
+	      {
+		_M_destroy_nodes(this->_M_impl._M_finish._M_node + 1,
+				 __new_finish._M_node + 1);
+		__throw_exception_again;
+	      }
+	  }
+	else
+	  _M_insert_aux(__pos, __first, __last, __n);
+      }
+
+  template<typename _Tp, typename _Alloc>
+#if __cplusplus >= 201103L
+    template<typename... _Args>
+      typename deque<_Tp, _Alloc>::iterator
+      deque<_Tp, _Alloc>::
+      _M_insert_aux(iterator __pos, _Args&&... __args)
+      {
+	value_type __x_copy(std::forward<_Args>(__args)...); // XXX copy
+#else
+    typename deque<_Tp, _Alloc>::iterator
+      deque<_Tp, _Alloc>::
+      _M_insert_aux(iterator __pos, const value_type& __x)
+      {
+	value_type __x_copy = __x; // XXX copy
+#endif
+	difference_type __index = __pos - this->_M_impl._M_start;
+	if (static_cast<size_type>(__index) < size() / 2)
+	  {
+	    push_front(_GLIBCXX_MOVE(front()));
+	    iterator __front1 = this->_M_impl._M_start;
+	    ++__front1;
+	    iterator __front2 = __front1;
+	    ++__front2;
+	    __pos = this->_M_impl._M_start + __index;
+	    iterator __pos1 = __pos;
+	    ++__pos1;
+	    _GLIBCXX_MOVE3(__front2, __pos1, __front1);
+	  }
+	else
+	  {
+	    push_back(_GLIBCXX_MOVE(back()));
+	    iterator __back1 = this->_M_impl._M_finish;
+	    --__back1;
+	    iterator __back2 = __back1;
+	    --__back2;
+	    __pos = this->_M_impl._M_start + __index;
+	    _GLIBCXX_MOVE_BACKWARD3(__pos, __back2, __back1);
+	  }
+	*__pos = _GLIBCXX_MOVE(__x_copy);
+	return __pos;
+      }
+
+  template <typename _Tp, typename _Alloc>
+    void
+    deque<_Tp, _Alloc>::
+    _M_insert_aux(iterator __pos, size_type __n, const value_type& __x)
+    {
+      const difference_type __elems_before = __pos - this->_M_impl._M_start;
+      const size_type __length = this->size();
+      value_type __x_copy = __x;
+      if (__elems_before < difference_type(__length / 2))
+	{
+	  iterator __new_start = _M_reserve_elements_at_front(__n);
+	  iterator __old_start = this->_M_impl._M_start;
+	  __pos = this->_M_impl._M_start + __elems_before;
+	  __try
+	    {
+	      if (__elems_before >= difference_type(__n))
+		{
+		  iterator __start_n = (this->_M_impl._M_start
+					+ difference_type(__n));
+		  std::__uninitialized_move_a(this->_M_impl._M_start,
+					      __start_n, __new_start,
+					      _M_get_Tp_allocator());
+		  this->_M_impl._M_start = __new_start;
+		  _GLIBCXX_MOVE3(__start_n, __pos, __old_start);
+		  std::fill(__pos - difference_type(__n), __pos, __x_copy);
+		}
+	      else
+		{
+		  std::__uninitialized_move_fill(this->_M_impl._M_start,
+						 __pos, __new_start,
+						 this->_M_impl._M_start,
+						 __x_copy,
+						 _M_get_Tp_allocator());
+		  this->_M_impl._M_start = __new_start;
+		  std::fill(__old_start, __pos, __x_copy);
+		}
+	    }
+	  __catch(...)
+	    {
+	      _M_destroy_nodes(__new_start._M_node,
+			       this->_M_impl._M_start._M_node);
+	      __throw_exception_again;
+	    }
+	}
+      else
+	{
+	  iterator __new_finish = _M_reserve_elements_at_back(__n);
+	  iterator __old_finish = this->_M_impl._M_finish;
+	  const difference_type __elems_after =
+	    difference_type(__length) - __elems_before;
+	  __pos = this->_M_impl._M_finish - __elems_after;
+	  __try
+	    {
+	      if (__elems_after > difference_type(__n))
+		{
+		  iterator __finish_n = (this->_M_impl._M_finish
+					 - difference_type(__n));
+		  std::__uninitialized_move_a(__finish_n,
+					      this->_M_impl._M_finish,
+					      this->_M_impl._M_finish,
+					      _M_get_Tp_allocator());
+		  this->_M_impl._M_finish = __new_finish;
+		  _GLIBCXX_MOVE_BACKWARD3(__pos, __finish_n, __old_finish);
+		  std::fill(__pos, __pos + difference_type(__n), __x_copy);
+		}
+	      else
+		{
+		  std::__uninitialized_fill_move(this->_M_impl._M_finish,
+						 __pos + difference_type(__n),
+						 __x_copy, __pos,
+						 this->_M_impl._M_finish,
+						 _M_get_Tp_allocator());
+		  this->_M_impl._M_finish = __new_finish;
+		  std::fill(__pos, __old_finish, __x_copy);
+		}
+	    }
+	  __catch(...)
+	    {
+	      _M_destroy_nodes(this->_M_impl._M_finish._M_node + 1,
+			       __new_finish._M_node + 1);
+	      __throw_exception_again;
+	    }
+	}
+    }
+
+  template <typename _Tp, typename _Alloc>
+    template <typename _ForwardIterator>
+      void
+      deque<_Tp, _Alloc>::
+      _M_insert_aux(iterator __pos,
+		    _ForwardIterator __first, _ForwardIterator __last,
+		    size_type __n)
+      {
+	const difference_type __elemsbefore = __pos - this->_M_impl._M_start;
+	const size_type __length = size();
+	if (static_cast<size_type>(__elemsbefore) < __length / 2)
+	  {
+	    iterator __new_start = _M_reserve_elements_at_front(__n);
+	    iterator __old_start = this->_M_impl._M_start;
+	    __pos = this->_M_impl._M_start + __elemsbefore;
+	    __try
+	      {
+		if (__elemsbefore >= difference_type(__n))
+		  {
+		    iterator __start_n = (this->_M_impl._M_start
+					  + difference_type(__n));
+		    std::__uninitialized_move_a(this->_M_impl._M_start,
+						__start_n, __new_start,
+						_M_get_Tp_allocator());
+		    this->_M_impl._M_start = __new_start;
+		    _GLIBCXX_MOVE3(__start_n, __pos, __old_start);
+		    std::copy(__first, __last, __pos - difference_type(__n));
+		  }
+		else
+		  {
+		    _ForwardIterator __mid = __first;
+		    std::advance(__mid, difference_type(__n) - __elemsbefore);
+		    std::__uninitialized_move_copy(this->_M_impl._M_start,
+						   __pos, __first, __mid,
+						   __new_start,
+						   _M_get_Tp_allocator());
+		    this->_M_impl._M_start = __new_start;
+		    std::copy(__mid, __last, __old_start);
+		  }
+	      }
+	    __catch(...)
+	      {
+		_M_destroy_nodes(__new_start._M_node,
+				 this->_M_impl._M_start._M_node);
+		__throw_exception_again;
+	      }
+	  }
+	else
+	{
+	  iterator __new_finish = _M_reserve_elements_at_back(__n);
+	  iterator __old_finish = this->_M_impl._M_finish;
+	  const difference_type __elemsafter =
+	    difference_type(__length) - __elemsbefore;
+	  __pos = this->_M_impl._M_finish - __elemsafter;
+	  __try
+	    {
+	      if (__elemsafter > difference_type(__n))
+		{
+		  iterator __finish_n = (this->_M_impl._M_finish
+					 - difference_type(__n));
+		  std::__uninitialized_move_a(__finish_n,
+					      this->_M_impl._M_finish,
+					      this->_M_impl._M_finish,
+					      _M_get_Tp_allocator());
+		  this->_M_impl._M_finish = __new_finish;
+		  _GLIBCXX_MOVE_BACKWARD3(__pos, __finish_n, __old_finish);
+		  std::copy(__first, __last, __pos);
+		}
+	      else
+		{
+		  _ForwardIterator __mid = __first;
+		  std::advance(__mid, __elemsafter);
+		  std::__uninitialized_copy_move(__mid, __last, __pos,
+						 this->_M_impl._M_finish,
+						 this->_M_impl._M_finish,
+						 _M_get_Tp_allocator());
+		  this->_M_impl._M_finish = __new_finish;
+		  std::copy(__first, __mid, __pos);
+		}
+	    }
+	  __catch(...)
+	    {
+	      _M_destroy_nodes(this->_M_impl._M_finish._M_node + 1,
+			       __new_finish._M_node + 1);
+	      __throw_exception_again;
+	    }
+	}
+      }
+
+   template<typename _Tp, typename _Alloc>
+     void
+     deque<_Tp, _Alloc>::
+     _M_destroy_data_aux(iterator __first, iterator __last)
+     {
+       for (_Map_pointer __node = __first._M_node + 1;
+	    __node < __last._M_node; ++__node)
+	 std::_Destroy(*__node, *__node + _S_buffer_size(),
+		       _M_get_Tp_allocator());
+
+       if (__first._M_node != __last._M_node)
+	 {
+	   std::_Destroy(__first._M_cur, __first._M_last,
+			 _M_get_Tp_allocator());
+	   std::_Destroy(__last._M_first, __last._M_cur,
+			 _M_get_Tp_allocator());
+	 }
+       else
+	 std::_Destroy(__first._M_cur, __last._M_cur,
+		       _M_get_Tp_allocator());
+     }
+
+  template <typename _Tp, typename _Alloc>
+    void
+    deque<_Tp, _Alloc>::
+    _M_new_elements_at_front(size_type __new_elems)
+    {
+      if (this->max_size() - this->size() < __new_elems)
+	__throw_length_error(__N("deque::_M_new_elements_at_front"));
+
+      const size_type __new_nodes = ((__new_elems + _S_buffer_size() - 1)
+				     / _S_buffer_size());
+      _M_reserve_map_at_front(__new_nodes);
+      size_type __i;
+      __try
+	{
+	  for (__i = 1; __i <= __new_nodes; ++__i)
+	    *(this->_M_impl._M_start._M_node - __i) = this->_M_allocate_node();
+	}
+      __catch(...)
+	{
+	  for (size_type __j = 1; __j < __i; ++__j)
+	    _M_deallocate_node(*(this->_M_impl._M_start._M_node - __j));
+	  __throw_exception_again;
+	}
+    }
+
+  template <typename _Tp, typename _Alloc>
+    void
+    deque<_Tp, _Alloc>::
+    _M_new_elements_at_back(size_type __new_elems)
+    {
+      if (this->max_size() - this->size() < __new_elems)
+	__throw_length_error(__N("deque::_M_new_elements_at_back"));
+
+      const size_type __new_nodes = ((__new_elems + _S_buffer_size() - 1)
+				     / _S_buffer_size());
+      _M_reserve_map_at_back(__new_nodes);
+      size_type __i;
+      __try
+	{
+	  for (__i = 1; __i <= __new_nodes; ++__i)
+	    *(this->_M_impl._M_finish._M_node + __i) = this->_M_allocate_node();
+	}
+      __catch(...)
+	{
+	  for (size_type __j = 1; __j < __i; ++__j)
+	    _M_deallocate_node(*(this->_M_impl._M_finish._M_node + __j));
+	  __throw_exception_again;
+	}
+    }
+
+  template <typename _Tp, typename _Alloc>
+    void
+    deque<_Tp, _Alloc>::
+    _M_reallocate_map(size_type __nodes_to_add, bool __add_at_front)
+    {
+      const size_type __old_num_nodes
+	= this->_M_impl._M_finish._M_node - this->_M_impl._M_start._M_node + 1;
+      const size_type __new_num_nodes = __old_num_nodes + __nodes_to_add;
+
+      _Map_pointer __new_nstart;
+      if (this->_M_impl._M_map_size > 2 * __new_num_nodes)
+	{
+	  __new_nstart = this->_M_impl._M_map + (this->_M_impl._M_map_size
+					 - __new_num_nodes) / 2
+			 + (__add_at_front ? __nodes_to_add : 0);
+	  if (__new_nstart < this->_M_impl._M_start._M_node)
+	    std::copy(this->_M_impl._M_start._M_node,
+		      this->_M_impl._M_finish._M_node + 1,
+		      __new_nstart);
+	  else
+	    std::copy_backward(this->_M_impl._M_start._M_node,
+			       this->_M_impl._M_finish._M_node + 1,
+			       __new_nstart + __old_num_nodes);
+	}
+      else
+	{
+	  size_type __new_map_size = this->_M_impl._M_map_size
+				     + std::max(this->_M_impl._M_map_size,
+						__nodes_to_add) + 2;
+
+	  _Map_pointer __new_map = this->_M_allocate_map(__new_map_size);
+	  __new_nstart = __new_map + (__new_map_size - __new_num_nodes) / 2
+			 + (__add_at_front ? __nodes_to_add : 0);
+	  std::copy(this->_M_impl._M_start._M_node,
+		    this->_M_impl._M_finish._M_node + 1,
+		    __new_nstart);
+	  _M_deallocate_map(this->_M_impl._M_map, this->_M_impl._M_map_size);
+
+	  this->_M_impl._M_map = __new_map;
+	  this->_M_impl._M_map_size = __new_map_size;
+	}
+
+      this->_M_impl._M_start._M_set_node(__new_nstart);
+      this->_M_impl._M_finish._M_set_node(__new_nstart + __old_num_nodes - 1);
+    }
+
+_GLIBCXX_END_NAMESPACE_CONTAINER
+
+  // Overload for deque::iterators, exploiting the "segmented-iterator
+  // optimization".
+  template<typename _Tp, typename _VTp>
+    void
+    __fill_a1(const _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Tp&, _Tp*>& __first,
+	      const _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Tp&, _Tp*>& __last,
+	      const _VTp& __value)
+    {
+      typedef _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Tp&, _Tp*> _Iter;
+      if (__first._M_node != __last._M_node)
+	{
+	  std::__fill_a1(__first._M_cur, __first._M_last, __value);
+
+	  for (typename _Iter::_Map_pointer __node = __first._M_node + 1;
+	       __node < __last._M_node; ++__node)
+	    std::__fill_a1(*__node, *__node + _Iter::_S_buffer_size(), __value);
+
+	  std::__fill_a1(__last._M_first, __last._M_cur, __value);
+	}
+      else
+	std::__fill_a1(__first._M_cur, __last._M_cur, __value);
+    }
+
+  template<bool _IsMove,
+	   typename _Tp, typename _Ref, typename _Ptr, typename _OI>
+    _OI
+    __copy_move_dit(_GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr> __first,
+		    _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr> __last,
+		    _OI __result)
+    {
+      typedef _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr> _Iter;
+      if (__first._M_node != __last._M_node)
+	{
+	  __result
+	    = std::__copy_move_a1<_IsMove>(__first._M_cur, __first._M_last,
+					   __result);
+
+	  for (typename _Iter::_Map_pointer __node = __first._M_node + 1;
+	       __node != __last._M_node; ++__node)
+	    __result
+	      = std::__copy_move_a1<_IsMove>(*__node,
+					     *__node + _Iter::_S_buffer_size(),
+					     __result);
+
+	  return std::__copy_move_a1<_IsMove>(__last._M_first, __last._M_cur,
+					      __result);
+	}
+
+      return std::__copy_move_a1<_IsMove>(__first._M_cur, __last._M_cur,
+					  __result);
+    }
+
+  template<bool _IsMove,
+	   typename _Tp, typename _Ref, typename _Ptr, typename _OI>
+    _OI
+    __copy_move_a1(_GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr> __first,
+		   _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr> __last,
+		   _OI __result)
+    { return __copy_move_dit<_IsMove>(__first, __last, __result); }
+
+  template<bool _IsMove,
+	   typename _ITp, typename _IRef, typename _IPtr, typename _OTp>
+    _GLIBCXX_STD_C::_Deque_iterator<_OTp, _OTp&, _OTp*>
+    __copy_move_a1(_GLIBCXX_STD_C::_Deque_iterator<_ITp, _IRef, _IPtr> __first,
+		   _GLIBCXX_STD_C::_Deque_iterator<_ITp, _IRef, _IPtr> __last,
+		   _GLIBCXX_STD_C::_Deque_iterator<_OTp, _OTp&, _OTp*> __result)
+    { return __copy_move_dit<_IsMove>(__first, __last, __result); }
+
+  template<bool _IsMove, typename _II, typename _Tp>
+    typename __gnu_cxx::__enable_if<
+      __is_random_access_iter<_II>::__value,
+      _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Tp&, _Tp*> >::__type
+    __copy_move_a1(_II __first, _II __last,
+		   _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Tp&, _Tp*> __result)
+    {
+      typedef _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Tp&, _Tp*> _Iter;
+      typedef typename _Iter::difference_type difference_type;
+
+      difference_type __len = __last - __first;
+      while (__len > 0)
+	{
+	  const difference_type __clen
+	    = std::min(__len, __result._M_last - __result._M_cur);
+	  std::__copy_move_a1<_IsMove>(__first, __first + __clen,
+				       __result._M_cur);
+
+	  __first += __clen;
+	  __result += __clen;
+	  __len -= __clen;
+	}
+
+      return __result;
+    }
+
+  template<bool _IsMove, typename _CharT>
+    typename __gnu_cxx::__enable_if<
+      __is_char<_CharT>::__value,
+      _GLIBCXX_STD_C::_Deque_iterator<_CharT, _CharT&, _CharT*> >::__type
+    __copy_move_a2(
+	istreambuf_iterator<_CharT, char_traits<_CharT> > __first,
+	istreambuf_iterator<_CharT, char_traits<_CharT> > __last,
+	_GLIBCXX_STD_C::_Deque_iterator<_CharT, _CharT&, _CharT*> __result)
+    {
+      if (__first == __last)
+	return __result;
+
+      for (;;)
+	{
+	  const std::ptrdiff_t __len = __result._M_last - __result._M_cur;
+	  const std::ptrdiff_t __nb
+	    = std::__copy_n_a(__first, __len, __result._M_cur, false)
+	    - __result._M_cur;
+	  __result += __nb;
+
+	  if (__nb != __len)
+	    break;
+	}
+
+      return __result;
+    }
+
+  template<typename _CharT, typename _Size>
+    typename __gnu_cxx::__enable_if<
+      __is_char<_CharT>::__value,
+      _GLIBCXX_STD_C::_Deque_iterator<_CharT, _CharT&, _CharT*> >::__type
+    __copy_n_a(
+      istreambuf_iterator<_CharT, char_traits<_CharT> > __it, _Size __size,
+      _GLIBCXX_STD_C::_Deque_iterator<_CharT, _CharT&, _CharT*> __result,
+      bool __strict)
+    {
+      if (__size == 0)
+	return __result;
+
+      do
+	{
+	  const _Size __len
+	    = std::min<_Size>(__result._M_last - __result._M_cur, __size);
+	  std::__copy_n_a(__it, __len, __result._M_cur, __strict);
+	  __result += __len;
+	  __size -= __len;
+	}
+      while (__size != 0);
+      return __result;
+    }
+
+  template<bool _IsMove,
+	   typename _Tp, typename _Ref, typename _Ptr, typename _OI>
+    _OI
+    __copy_move_backward_dit(
+		_GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr> __first,
+		_GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr> __last,
+		_OI __result)
+    {
+      typedef _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr> _Iter;
+      if (__first._M_node != __last._M_node)
+	{
+	  __result = std::__copy_move_backward_a1<_IsMove>(
+		__last._M_first, __last._M_cur, __result);
+
+	  for (typename _Iter::_Map_pointer __node = __last._M_node - 1;
+	       __node != __first._M_node; --__node)
+	    __result = std::__copy_move_backward_a1<_IsMove>(
+		*__node, *__node + _Iter::_S_buffer_size(), __result);
+
+	  return std::__copy_move_backward_a1<_IsMove>(
+			__first._M_cur, __first._M_last, __result);
+	}
+
+      return std::__copy_move_backward_a1<_IsMove>(
+		__first._M_cur, __last._M_cur, __result);
+    }
+
+  template<bool _IsMove,
+	   typename _Tp, typename _Ref, typename _Ptr, typename _OI>
+    _OI
+    __copy_move_backward_a1(
+		_GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr> __first,
+		_GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr> __last,
+		_OI __result)
+    { return __copy_move_backward_dit<_IsMove>(__first, __last, __result); }
+
+  template<bool _IsMove,
+	   typename _ITp, typename _IRef, typename _IPtr, typename _OTp>
+    _GLIBCXX_STD_C::_Deque_iterator<_OTp, _OTp&, _OTp*>
+    __copy_move_backward_a1(
+		_GLIBCXX_STD_C::_Deque_iterator<_ITp, _IRef, _IPtr> __first,
+		_GLIBCXX_STD_C::_Deque_iterator<_ITp, _IRef, _IPtr> __last,
+		_GLIBCXX_STD_C::_Deque_iterator<_OTp, _OTp&, _OTp*> __result)
+    { return __copy_move_backward_dit<_IsMove>(__first, __last, __result); }
+
+  template<bool _IsMove, typename _II, typename _Tp>
+    typename __gnu_cxx::__enable_if<
+      __is_random_access_iter<_II>::__value,
+      _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Tp&, _Tp*> >::__type
+    __copy_move_backward_a1(_II __first, _II __last,
+		_GLIBCXX_STD_C::_Deque_iterator<_Tp, _Tp&, _Tp*> __result)
+    {
+      typedef _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Tp&, _Tp*> _Iter;
+      typedef typename _Iter::difference_type difference_type;
+
+      difference_type __len = __last - __first;
+      while (__len > 0)
+	{
+	  difference_type __rlen = __result._M_cur - __result._M_first;
+	  _Tp* __rend = __result._M_cur;
+	  if (!__rlen)
+	    {
+	      __rlen = _Iter::_S_buffer_size();
+	      __rend = *(__result._M_node - 1) + __rlen;
+	    }
+
+	  const difference_type __clen = std::min(__len, __rlen);
+	  std::__copy_move_backward_a1<_IsMove>(__last - __clen, __last, __rend);
+
+	  __last -= __clen;
+	  __result -= __clen;
+	  __len -= __clen;
+	}
+
+      return __result;
+    }
+
+  template<typename _Tp, typename _Ref, typename _Ptr, typename _II>
+    bool
+    __equal_dit(
+	const _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr>& __first1,
+	const _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr>& __last1,
+	_II __first2)
+    {
+      typedef _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr> _Iter;
+      if (__first1._M_node != __last1._M_node)
+	{
+	  if (!std::__equal_aux1(__first1._M_cur, __first1._M_last, __first2))
+	    return false;
+
+	  __first2 += __first1._M_last - __first1._M_cur;
+	  for (typename _Iter::_Map_pointer __node = __first1._M_node + 1;
+	       __node != __last1._M_node;
+	       __first2 += _Iter::_S_buffer_size(), ++__node)
+	    if (!std::__equal_aux1(*__node, *__node + _Iter::_S_buffer_size(),
+				  __first2))
+	      return false;
+
+	  return std::__equal_aux1(__last1._M_first, __last1._M_cur, __first2);
+	}
+
+      return std::__equal_aux1(__first1._M_cur, __last1._M_cur, __first2);
+    }
+
+  template<typename _Tp, typename _Ref, typename _Ptr, typename _II>
+    typename __gnu_cxx::__enable_if<
+      __is_random_access_iter<_II>::__value, bool>::__type
+    __equal_aux1(_GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr> __first1,
+		 _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr> __last1,
+		 _II __first2)
+    { return std::__equal_dit(__first1, __last1, __first2); }
+
+  template<typename _Tp1, typename _Ref1, typename _Ptr1,
+	   typename _Tp2, typename _Ref2, typename _Ptr2>
+    bool
+    __equal_aux1(_GLIBCXX_STD_C::_Deque_iterator<_Tp1, _Ref1, _Ptr1> __first1,
+		 _GLIBCXX_STD_C::_Deque_iterator<_Tp1, _Ref1, _Ptr1> __last1,
+		 _GLIBCXX_STD_C::_Deque_iterator<_Tp2, _Ref2, _Ptr2> __first2)
+    { return std::__equal_dit(__first1, __last1, __first2); }
+
+  template<typename _II, typename _Tp, typename _Ref, typename _Ptr>
+    typename __gnu_cxx::__enable_if<
+      __is_random_access_iter<_II>::__value, bool>::__type
+    __equal_aux1(_II __first1, _II __last1,
+		_GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr> __first2)
+    {
+      typedef _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr> _Iter;
+      typedef typename _Iter::difference_type difference_type;
+
+      difference_type __len = __last1 - __first1;
+      while (__len > 0)
+	{
+	  const difference_type __clen
+	    = std::min(__len, __first2._M_last - __first2._M_cur);
+	  if (!std::__equal_aux1(__first1, __first1 + __clen, __first2._M_cur))
+	    return false;
+
+	  __first1 += __clen;
+	  __len -= __clen;
+	  __first2 += __clen;
+	}
+
+      return true;
+    }
+
+  template<typename _Tp1, typename _Ref, typename _Ptr, typename _Tp2>
+    int
+    __lex_cmp_dit(
+	_GLIBCXX_STD_C::_Deque_iterator<_Tp1, _Ref, _Ptr> __first1,
+	_GLIBCXX_STD_C::_Deque_iterator<_Tp1, _Ref, _Ptr> __last1,
+	const _Tp2* __first2, const _Tp2* __last2)
+    {
+      const bool __simple =
+	(__is_memcmp_ordered_with<_Tp1, _Tp2>::__value
+	 && __is_pointer<_Ptr>::__value
+#if __cplusplus > 201703L && __cpp_lib_concepts
+	 // For C++20 iterator_traits<volatile T*>::value_type is non-volatile
+	 // so __is_byte<T> could be true, but we can't use memcmp with
+	 // volatile data.
+	 && !is_volatile_v<_Tp1>
+	 && !is_volatile_v<_Tp2>
+#endif
+	 );
+      typedef std::__lexicographical_compare<__simple> _Lc;
+
+      while (__first1._M_node != __last1._M_node)
+	{
+	  const ptrdiff_t __len1 = __first1._M_last - __first1._M_cur;
+	  const ptrdiff_t __len2 = __last2 - __first2;
+	  const ptrdiff_t __len = std::min(__len1, __len2);
+	  // if __len1 > __len2 this will return a positive value:
+	  if (int __ret = _Lc::__3way(__first1._M_cur, __first1._M_last,
+				      __first2, __first2 + __len))
+	    return __ret;
+
+	  __first1 += __len;
+	  __first2 += __len;
+	}
+      return _Lc::__3way(__first1._M_cur, __last1._M_cur,
+			 __first2, __last2);
+    }
+
+  template<typename _Tp1, typename _Ref1, typename _Ptr1,
+	   typename _Tp2>
+    inline bool
+    __lexicographical_compare_aux1(
+	_GLIBCXX_STD_C::_Deque_iterator<_Tp1, _Ref1, _Ptr1> __first1,
+	_GLIBCXX_STD_C::_Deque_iterator<_Tp1, _Ref1, _Ptr1> __last1,
+	_Tp2* __first2, _Tp2* __last2)
+    { return std::__lex_cmp_dit(__first1, __last1, __first2, __last2) < 0; }
+
+  template<typename _Tp1,
+	   typename _Tp2, typename _Ref2, typename _Ptr2>
+    inline  bool
+    __lexicographical_compare_aux1(_Tp1* __first1, _Tp1* __last1,
+	_GLIBCXX_STD_C::_Deque_iterator<_Tp2, _Ref2, _Ptr2> __first2,
+	_GLIBCXX_STD_C::_Deque_iterator<_Tp2, _Ref2, _Ptr2> __last2)
+    { return std::__lex_cmp_dit(__first2, __last2, __first1, __last1) > 0; }
+
+  template<typename _Tp1, typename _Ref1, typename _Ptr1,
+	   typename _Tp2, typename _Ref2, typename _Ptr2>
+    inline bool
+    __lexicographical_compare_aux1(
+		_GLIBCXX_STD_C::_Deque_iterator<_Tp1, _Ref1, _Ptr1> __first1,
+		_GLIBCXX_STD_C::_Deque_iterator<_Tp1, _Ref1, _Ptr1> __last1,
+		_GLIBCXX_STD_C::_Deque_iterator<_Tp2, _Ref2, _Ptr2> __first2,
+		_GLIBCXX_STD_C::_Deque_iterator<_Tp2, _Ref2, _Ptr2> __last2)
+    {
+      const bool __simple =
+	(__is_memcmp_ordered_with<_Tp1, _Tp2>::__value
+	 && __is_pointer<_Ptr1>::__value
+	 && __is_pointer<_Ptr2>::__value
+#if __cplusplus > 201703L && __cpp_lib_concepts
+	 // For C++20 iterator_traits<volatile T*>::value_type is non-volatile
+	 // so __is_byte<T> could be true, but we can't use memcmp with
+	 // volatile data.
+	 && !is_volatile_v<_Tp1>
+	 && !is_volatile_v<_Tp2>
+#endif
+	 );
+      typedef std::__lexicographical_compare<__simple> _Lc;
+
+      while (__first1 != __last1)
+	{
+	  const ptrdiff_t __len2 = __first2._M_node == __last2._M_node
+	    ? __last2._M_cur - __first2._M_cur
+	    : __first2._M_last - __first2._M_cur;
+	  if (__len2 == 0)
+	    return false;
+	  const ptrdiff_t __len1 = __first1._M_node == __last1._M_node
+	    ? __last1._M_cur - __first1._M_cur
+	    : __first1._M_last - __first1._M_cur;
+	  const ptrdiff_t __len = std::min(__len1, __len2);
+	  if (int __ret = _Lc::__3way(__first1._M_cur, __first1._M_cur + __len,
+				      __first2._M_cur, __first2._M_cur + __len))
+	    return __ret < 0;
+
+	  __first1 += __len;
+	  __first2 += __len;
+	}
+
+      return __last2 != __first2;
+    }
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@enable_special_members.h
@@ -0,0 +1,316 @@
+// <bits/enable_special_members.h> -*- C++ -*-
+
+// Copyright (C) 2013-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/enable_special_members.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly.
+ */
+
+#ifndef _ENABLE_SPECIAL_MEMBERS_H
+#define _ENABLE_SPECIAL_MEMBERS_H 1
+
+#pragma GCC system_header
+
+#include <bits/c++config.h>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+/// @cond undocumented
+
+  struct _Enable_default_constructor_tag
+  {
+    explicit constexpr _Enable_default_constructor_tag() = default;
+  };
+
+/**
+  * @brief A mixin helper to conditionally enable or disable the default
+  * constructor.
+  * @sa _Enable_special_members
+  */
+template<bool _Switch, typename _Tag = void>
+  struct _Enable_default_constructor
+  {
+    constexpr _Enable_default_constructor() noexcept = default;
+    constexpr _Enable_default_constructor(_Enable_default_constructor const&)
+      noexcept  = default;
+    constexpr _Enable_default_constructor(_Enable_default_constructor&&)
+      noexcept = default;
+    _Enable_default_constructor&
+    operator=(_Enable_default_constructor const&) noexcept = default;
+    _Enable_default_constructor&
+    operator=(_Enable_default_constructor&&) noexcept = default;
+
+    // Can be used in other ctors.
+    constexpr explicit
+    _Enable_default_constructor(_Enable_default_constructor_tag) { }
+  };
+
+
+/**
+  * @brief A mixin helper to conditionally enable or disable the default
+  * destructor.
+  * @sa _Enable_special_members
+  */
+template<bool _Switch, typename _Tag = void>
+  struct _Enable_destructor { };
+
+/**
+  * @brief A mixin helper to conditionally enable or disable the copy/move
+  * special members.
+  * @sa _Enable_special_members
+  */
+template<bool _Copy, bool _CopyAssignment,
+         bool _Move, bool _MoveAssignment,
+         typename _Tag = void>
+  struct _Enable_copy_move { };
+
+/**
+  * @brief A mixin helper to conditionally enable or disable the special
+  * members.
+  *
+  * The @c _Tag type parameter is to make mixin bases unique and thus avoid
+  * ambiguities.
+  */
+template<bool _Default, bool _Destructor,
+         bool _Copy, bool _CopyAssignment,
+         bool _Move, bool _MoveAssignment,
+         typename _Tag = void>
+  struct _Enable_special_members
+  : private _Enable_default_constructor<_Default, _Tag>,
+    private _Enable_destructor<_Destructor, _Tag>,
+    private _Enable_copy_move<_Copy, _CopyAssignment,
+                              _Move, _MoveAssignment,
+                              _Tag>
+  { };
+
+// Boilerplate follows.
+
+template<typename _Tag>
+  struct _Enable_default_constructor<false, _Tag>
+  {
+    constexpr _Enable_default_constructor() noexcept = delete;
+    constexpr _Enable_default_constructor(_Enable_default_constructor const&)
+      noexcept  = default;
+    constexpr _Enable_default_constructor(_Enable_default_constructor&&)
+      noexcept = default;
+    _Enable_default_constructor&
+    operator=(_Enable_default_constructor const&) noexcept = default;
+    _Enable_default_constructor&
+    operator=(_Enable_default_constructor&&) noexcept = default;
+
+    // Can be used in other ctors.
+    constexpr explicit
+    _Enable_default_constructor(_Enable_default_constructor_tag) { }
+  };
+
+template<typename _Tag>
+  struct _Enable_destructor<false, _Tag>
+  { ~_Enable_destructor() noexcept = delete; };
+
+template<typename _Tag>
+  struct _Enable_copy_move<false, true, true, true, _Tag>
+  {
+    constexpr _Enable_copy_move() noexcept                          = default;
+    constexpr _Enable_copy_move(_Enable_copy_move const&) noexcept  = delete;
+    constexpr _Enable_copy_move(_Enable_copy_move&&) noexcept       = default;
+    _Enable_copy_move&
+    operator=(_Enable_copy_move const&) noexcept                    = default;
+    _Enable_copy_move&
+    operator=(_Enable_copy_move&&) noexcept                         = default;
+  };
+
+template<typename _Tag>
+  struct _Enable_copy_move<true, false, true, true, _Tag>
+  {
+    constexpr _Enable_copy_move() noexcept                          = default;
+    constexpr _Enable_copy_move(_Enable_copy_move const&) noexcept  = default;
+    constexpr _Enable_copy_move(_Enable_copy_move&&) noexcept       = default;
+    _Enable_copy_move&
+    operator=(_Enable_copy_move const&) noexcept                    = delete;
+    _Enable_copy_move&
+    operator=(_Enable_copy_move&&) noexcept                         = default;
+  };
+
+template<typename _Tag>
+  struct _Enable_copy_move<false, false, true, true, _Tag>
+  {
+    constexpr _Enable_copy_move() noexcept                          = default;
+    constexpr _Enable_copy_move(_Enable_copy_move const&) noexcept  = delete;
+    constexpr _Enable_copy_move(_Enable_copy_move&&) noexcept       = default;
+    _Enable_copy_move&
+    operator=(_Enable_copy_move const&) noexcept                    = delete;
+    _Enable_copy_move&
+    operator=(_Enable_copy_move&&) noexcept                         = default;
+  };
+
+template<typename _Tag>
+  struct _Enable_copy_move<true, true, false, true, _Tag>
+  {
+    constexpr _Enable_copy_move() noexcept                          = default;
+    constexpr _Enable_copy_move(_Enable_copy_move const&) noexcept  = default;
+    constexpr _Enable_copy_move(_Enable_copy_move&&) noexcept       = delete;
+    _Enable_copy_move&
+    operator=(_Enable_copy_move const&) noexcept                    = default;
+    _Enable_copy_move&
+    operator=(_Enable_copy_move&&) noexcept                         = default;
+  };
+
+template<typename _Tag>
+  struct _Enable_copy_move<false, true, false, true, _Tag>
+  {
+    constexpr _Enable_copy_move() noexcept                          = default;
+    constexpr _Enable_copy_move(_Enable_copy_move const&) noexcept  = delete;
+    constexpr _Enable_copy_move(_Enable_copy_move&&) noexcept       = delete;
+    _Enable_copy_move&
+    operator=(_Enable_copy_move const&) noexcept                    = default;
+    _Enable_copy_move&
+    operator=(_Enable_copy_move&&) noexcept                         = default;
+  };
+
+template<typename _Tag>
+  struct _Enable_copy_move<true, false, false, true, _Tag>
+  {
+    constexpr _Enable_copy_move() noexcept                          = default;
+    constexpr _Enable_copy_move(_Enable_copy_move const&) noexcept  = default;
+    constexpr _Enable_copy_move(_Enable_copy_move&&) noexcept       = delete;
+    _Enable_copy_move&
+    operator=(_Enable_copy_move const&) noexcept                    = delete;
+    _Enable_copy_move&
+    operator=(_Enable_copy_move&&) noexcept                         = default;
+  };
+
+template<typename _Tag>
+  struct _Enable_copy_move<false, false, false, true, _Tag>
+  {
+    constexpr _Enable_copy_move() noexcept                          = default;
+    constexpr _Enable_copy_move(_Enable_copy_move const&) noexcept  = delete;
+    constexpr _Enable_copy_move(_Enable_copy_move&&) noexcept       = delete;
+    _Enable_copy_move&
+    operator=(_Enable_copy_move const&) noexcept                    = delete;
+    _Enable_copy_move&
+    operator=(_Enable_copy_move&&) noexcept                         = default;
+  };
+
+template<typename _Tag>
+  struct _Enable_copy_move<true, true, true, false, _Tag>
+  {
+    constexpr _Enable_copy_move() noexcept                          = default;
+    constexpr _Enable_copy_move(_Enable_copy_move const&) noexcept  = default;
+    constexpr _Enable_copy_move(_Enable_copy_move&&) noexcept       = default;
+    _Enable_copy_move&
+    operator=(_Enable_copy_move const&) noexcept                    = default;
+    _Enable_copy_move&
+    operator=(_Enable_copy_move&&) noexcept                         = delete;
+  };
+
+template<typename _Tag>
+  struct _Enable_copy_move<false, true, true, false, _Tag>
+  {
+    constexpr _Enable_copy_move() noexcept                          = default;
+    constexpr _Enable_copy_move(_Enable_copy_move const&) noexcept  = delete;
+    constexpr _Enable_copy_move(_Enable_copy_move&&) noexcept       = default;
+    _Enable_copy_move&
+    operator=(_Enable_copy_move const&) noexcept                    = default;
+    _Enable_copy_move&
+    operator=(_Enable_copy_move&&) noexcept                         = delete;
+  };
+
+template<typename _Tag>
+  struct _Enable_copy_move<true, false, true, false, _Tag>
+  {
+    constexpr _Enable_copy_move() noexcept                          = default;
+    constexpr _Enable_copy_move(_Enable_copy_move const&) noexcept  = default;
+    constexpr _Enable_copy_move(_Enable_copy_move&&) noexcept       = default;
+    _Enable_copy_move&
+    operator=(_Enable_copy_move const&) noexcept                    = delete;
+    _Enable_copy_move&
+    operator=(_Enable_copy_move&&) noexcept                         = delete;
+  };
+
+template<typename _Tag>
+  struct _Enable_copy_move<false, false, true, false, _Tag>
+  {
+    constexpr _Enable_copy_move() noexcept                          = default;
+    constexpr _Enable_copy_move(_Enable_copy_move const&) noexcept  = delete;
+    constexpr _Enable_copy_move(_Enable_copy_move&&) noexcept       = default;
+    _Enable_copy_move&
+    operator=(_Enable_copy_move const&) noexcept                    = delete;
+    _Enable_copy_move&
+    operator=(_Enable_copy_move&&) noexcept                         = delete;
+  };
+
+template<typename _Tag>
+  struct _Enable_copy_move<true, true, false, false, _Tag>
+  {
+    constexpr _Enable_copy_move() noexcept                          = default;
+    constexpr _Enable_copy_move(_Enable_copy_move const&) noexcept  = default;
+    constexpr _Enable_copy_move(_Enable_copy_move&&) noexcept       = delete;
+    _Enable_copy_move&
+    operator=(_Enable_copy_move const&) noexcept                    = default;
+    _Enable_copy_move&
+    operator=(_Enable_copy_move&&) noexcept                         = delete;
+  };
+
+template<typename _Tag>
+  struct _Enable_copy_move<false, true, false, false, _Tag>
+  {
+    constexpr _Enable_copy_move() noexcept                          = default;
+    constexpr _Enable_copy_move(_Enable_copy_move const&) noexcept  = delete;
+    constexpr _Enable_copy_move(_Enable_copy_move&&) noexcept       = delete;
+    _Enable_copy_move&
+    operator=(_Enable_copy_move const&) noexcept                    = default;
+    _Enable_copy_move&
+    operator=(_Enable_copy_move&&) noexcept                         = delete;
+  };
+
+template<typename _Tag>
+  struct _Enable_copy_move<true, false, false, false, _Tag>
+  {
+    constexpr _Enable_copy_move() noexcept                          = default;
+    constexpr _Enable_copy_move(_Enable_copy_move const&) noexcept  = default;
+    constexpr _Enable_copy_move(_Enable_copy_move&&) noexcept       = delete;
+    _Enable_copy_move&
+    operator=(_Enable_copy_move const&) noexcept                    = delete;
+    _Enable_copy_move&
+    operator=(_Enable_copy_move&&) noexcept                         = delete;
+  };
+
+template<typename _Tag>
+  struct _Enable_copy_move<false, false, false, false, _Tag>
+  {
+    constexpr _Enable_copy_move() noexcept                          = default;
+    constexpr _Enable_copy_move(_Enable_copy_move const&) noexcept  = delete;
+    constexpr _Enable_copy_move(_Enable_copy_move&&) noexcept       = delete;
+    _Enable_copy_move&
+    operator=(_Enable_copy_move const&) noexcept                    = delete;
+    _Enable_copy_move&
+    operator=(_Enable_copy_move&&) noexcept                         = delete;
+  };
+
+/// @endcond
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif // _ENABLE_SPECIAL_MEMBERS_H
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@erase_if.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@erase_if.h
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@erase_if.h
@@ -0,0 +1,76 @@
+// <bits/erase_if.h> -*- C++ -*-
+
+// Copyright (C) 2015-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/erase_if.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly.
+ */
+
+#ifndef _GLIBCXX_ERASE_IF_H
+#define _GLIBCXX_ERASE_IF_H 1
+
+#pragma GCC system_header
+
+#if __cplusplus >= 201402L
+
+#include <bits/c++config.h>
+
+namespace std
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+#if __cplusplus > 201703L
+# define __cpp_lib_erase_if 202002L
+#endif
+
+  namespace __detail
+  {
+    template<typename _Container, typename _UnsafeContainer,
+	     typename _Predicate>
+      typename _Container::size_type
+      __erase_nodes_if(_Container& __cont, const _UnsafeContainer& __ucont,
+		       _Predicate __pred)
+      {
+	typename _Container::size_type __num = 0;
+	for (auto __iter = __ucont.begin(), __last = __ucont.end();
+	     __iter != __last;)
+	  {
+	    if (__pred(*__iter))
+	      {
+		__iter = __cont.erase(__iter);
+		++__num;
+	      }
+	    else
+	      ++__iter;
+	  }
+	return __num;
+      }
+  } // namespace __detail
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif // C++14
+
+#endif // _GLIBCXX_ERASE_IF_H
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@exception.h
@@ -0,0 +1,87 @@
+// Exception Handling support header for -*- C++ -*-
+
+// Copyright (C) 2016-2022 Free Software Foundation, Inc.
+//
+// This file is part of GCC.
+//
+// GCC is free software; you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation; either version 3, or (at your option)
+// any later version.
+//
+// GCC is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/exception.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly.
+ */
+
+#ifndef __EXCEPTION_H
+#define __EXCEPTION_H 1
+
+#pragma GCC system_header
+
+#pragma GCC visibility push(default)
+
+#include <bits/c++config.h>
+
+extern "C++" {
+
+namespace std
+{
+  /**
+   * @defgroup exceptions Exceptions
+   * @ingroup diagnostics
+   * @since C++98
+   *
+   * Classes and functions for reporting errors via exceptions.
+   * @{
+   */
+
+  /**
+   *  @brief Base class for all library exceptions.
+   *
+   *  This is the base class for all exceptions thrown by the standard
+   *  library, and by certain language expressions.  You are free to derive
+   *  your own %exception classes, or use a different hierarchy, or to
+   *  throw non-class data (e.g., fundamental types).
+   */
+  class exception
+  {
+  public:
+    exception() _GLIBCXX_NOTHROW { }
+    virtual ~exception() _GLIBCXX_TXN_SAFE_DYN _GLIBCXX_NOTHROW;
+#if __cplusplus >= 201103L
+    exception(const exception&) = default;
+    exception& operator=(const exception&) = default;
+    exception(exception&&) = default;
+    exception& operator=(exception&&) = default;
+#endif
+
+    /** Returns a C-style character string describing the general cause
+     *  of the current error.  */
+    virtual const char*
+    what() const _GLIBCXX_TXN_SAFE_DYN _GLIBCXX_NOTHROW;
+  };
+
+  /// @}
+
+} // namespace std
+
+}
+
+#pragma GCC visibility pop
+
+#endif
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@exception_defines.h
@@ -0,0 +1,45 @@
+// -fno-exceptions Support -*- C++ -*-
+
+// Copyright (C) 2001-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/exception_defines.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{exception}
+ */
+
+#ifndef _EXCEPTION_DEFINES_H
+#define _EXCEPTION_DEFINES_H 1
+
+#if ! __cpp_exceptions
+// Iff -fno-exceptions, transform error handling code to work without it.
+# define __try      if (true)
+# define __catch(X) if (false)
+# define __throw_exception_again
+#else
+// Else proceed normally.
+# define __try      try
+# define __catch(X) catch(X)
+# define __throw_exception_again throw
+#endif
+
+#endif
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@exception_ptr.h
@@ -0,0 +1,288 @@
+// Exception Handling support header (exception_ptr class) for -*- C++ -*-
+
+// Copyright (C) 2008-2022 Free Software Foundation, Inc.
+//
+// This file is part of GCC.
+//
+// GCC is free software; you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation; either version 3, or (at your option)
+// any later version.
+// 
+// GCC is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+// 
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/exception_ptr.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{exception}
+ */
+
+#ifndef _EXCEPTION_PTR_H
+#define _EXCEPTION_PTR_H
+
+#pragma GCC visibility push(default)
+
+#include <bits/c++config.h>
+#include <bits/exception_defines.h>
+#include <bits/cxxabi_init_exception.h>
+#include <typeinfo>
+#include <new>
+
+#if __cplusplus >= 201103L
+# include <bits/move.h>
+#endif
+
+#ifdef _GLIBCXX_EH_PTR_RELOPS_COMPAT
+# define _GLIBCXX_EH_PTR_USED __attribute__((__used__))
+#else
+# define _GLIBCXX_EH_PTR_USED
+#endif
+
+extern "C++" {
+
+namespace std 
+{
+  class type_info;
+
+  /**
+   * @addtogroup exceptions
+   * @{
+   */
+
+  namespace __exception_ptr
+  {
+    class exception_ptr;
+  }
+
+  using __exception_ptr::exception_ptr;
+
+  /** Obtain an exception_ptr to the currently handled exception. If there
+   *  is none, or the currently handled exception is foreign, return the null
+   *  value.
+   */
+  exception_ptr current_exception() _GLIBCXX_USE_NOEXCEPT;
+
+  template<typename _Ex>
+  exception_ptr make_exception_ptr(_Ex) _GLIBCXX_USE_NOEXCEPT;
+
+  /// Throw the object pointed to by the exception_ptr.
+  void rethrow_exception(exception_ptr) __attribute__ ((__noreturn__));
+
+  namespace __exception_ptr
+  {
+    using std::rethrow_exception;
+
+    /**
+     *  @brief An opaque pointer to an arbitrary exception.
+     *  @ingroup exceptions
+     */
+    class exception_ptr
+    {
+      void* _M_exception_object;
+
+      explicit exception_ptr(void* __e) _GLIBCXX_USE_NOEXCEPT;
+
+      void _M_addref() _GLIBCXX_USE_NOEXCEPT;
+      void _M_release() _GLIBCXX_USE_NOEXCEPT;
+
+      void *_M_get() const _GLIBCXX_NOEXCEPT __attribute__ ((__pure__));
+
+      friend exception_ptr std::current_exception() _GLIBCXX_USE_NOEXCEPT;
+      friend void std::rethrow_exception(exception_ptr);
+      template<typename _Ex>
+      friend exception_ptr std::make_exception_ptr(_Ex) _GLIBCXX_USE_NOEXCEPT;
+
+    public:
+      exception_ptr() _GLIBCXX_USE_NOEXCEPT;
+
+      exception_ptr(const exception_ptr&) _GLIBCXX_USE_NOEXCEPT;
+
+#if __cplusplus >= 201103L
+      exception_ptr(nullptr_t) noexcept
+      : _M_exception_object(nullptr)
+      { }
+
+      exception_ptr(exception_ptr&& __o) noexcept
+      : _M_exception_object(__o._M_exception_object)
+      { __o._M_exception_object = nullptr; }
+#endif
+
+#if (__cplusplus < 201103L) || defined (_GLIBCXX_EH_PTR_COMPAT)
+      typedef void (exception_ptr::*__safe_bool)();
+
+      // For construction from nullptr or 0.
+      exception_ptr(__safe_bool) _GLIBCXX_USE_NOEXCEPT;
+#endif
+
+      exception_ptr& 
+      operator=(const exception_ptr&) _GLIBCXX_USE_NOEXCEPT;
+
+#if __cplusplus >= 201103L
+      exception_ptr& 
+      operator=(exception_ptr&& __o) noexcept
+      {
+        exception_ptr(static_cast<exception_ptr&&>(__o)).swap(*this);
+        return *this;
+      }
+#endif
+
+      ~exception_ptr() _GLIBCXX_USE_NOEXCEPT;
+
+      void 
+      swap(exception_ptr&) _GLIBCXX_USE_NOEXCEPT;
+
+#ifdef _GLIBCXX_EH_PTR_COMPAT
+      // Retained for compatibility with CXXABI_1.3.
+      void _M_safe_bool_dummy() _GLIBCXX_USE_NOEXCEPT
+	__attribute__ ((__const__));
+      bool operator!() const _GLIBCXX_USE_NOEXCEPT
+	__attribute__ ((__pure__));
+      operator __safe_bool() const _GLIBCXX_USE_NOEXCEPT;
+#endif
+
+#if __cplusplus >= 201103L
+      explicit operator bool() const noexcept
+      { return _M_exception_object; }
+#endif
+
+#if __cpp_impl_three_way_comparison >= 201907L \
+      && ! defined _GLIBCXX_EH_PTR_RELOPS_COMPAT
+      friend bool
+      operator==(const exception_ptr&, const exception_ptr&) noexcept = default;
+#else
+      friend _GLIBCXX_EH_PTR_USED bool
+      operator==(const exception_ptr& __x, const exception_ptr& __y)
+      _GLIBCXX_USE_NOEXCEPT
+      { return __x._M_exception_object == __y._M_exception_object; }
+
+      friend _GLIBCXX_EH_PTR_USED bool
+      operator!=(const exception_ptr& __x, const exception_ptr& __y)
+      _GLIBCXX_USE_NOEXCEPT
+      { return __x._M_exception_object != __y._M_exception_object; }
+#endif
+
+      const class std::type_info*
+      __cxa_exception_type() const _GLIBCXX_USE_NOEXCEPT
+	__attribute__ ((__pure__));
+    };
+
+    _GLIBCXX_EH_PTR_USED
+    inline
+    exception_ptr::exception_ptr() _GLIBCXX_USE_NOEXCEPT
+    : _M_exception_object(0)
+    { }
+
+    _GLIBCXX_EH_PTR_USED
+    inline
+    exception_ptr::exception_ptr(const exception_ptr& __other)
+    _GLIBCXX_USE_NOEXCEPT
+    : _M_exception_object(__other._M_exception_object)
+    {
+      if (_M_exception_object)
+	_M_addref();
+    }
+
+    _GLIBCXX_EH_PTR_USED
+    inline
+    exception_ptr::~exception_ptr() _GLIBCXX_USE_NOEXCEPT
+    {
+      if (_M_exception_object)
+	_M_release();
+    }
+
+    _GLIBCXX_EH_PTR_USED
+    inline exception_ptr&
+    exception_ptr::operator=(const exception_ptr& __other) _GLIBCXX_USE_NOEXCEPT
+    {
+      exception_ptr(__other).swap(*this);
+      return *this;
+    }
+
+    _GLIBCXX_EH_PTR_USED
+    inline void
+    exception_ptr::swap(exception_ptr &__other) _GLIBCXX_USE_NOEXCEPT
+    {
+      void *__tmp = _M_exception_object;
+      _M_exception_object = __other._M_exception_object;
+      __other._M_exception_object = __tmp;
+    }
+
+    /// @relates exception_ptr
+    inline void
+    swap(exception_ptr& __lhs, exception_ptr& __rhs)
+    { __lhs.swap(__rhs); }
+
+    /// @cond undocumented
+    template<typename _Ex>
+      _GLIBCXX_CDTOR_CALLABI
+      inline void
+      __dest_thunk(void* __x)
+      { static_cast<_Ex*>(__x)->~_Ex(); }
+    /// @endcond
+
+  } // namespace __exception_ptr
+
+  /// Obtain an exception_ptr pointing to a copy of the supplied object.
+#if (__cplusplus >= 201103L && __cpp_rtti) || __cpp_exceptions
+  template<typename _Ex>
+    exception_ptr
+    make_exception_ptr(_Ex __ex) _GLIBCXX_USE_NOEXCEPT
+    {
+#if __cplusplus >= 201103L && __cpp_rtti
+      using _Ex2 = typename decay<_Ex>::type;
+      void* __e = __cxxabiv1::__cxa_allocate_exception(sizeof(_Ex));
+      (void) __cxxabiv1::__cxa_init_primary_exception(
+	  __e, const_cast<std::type_info*>(&typeid(_Ex)),
+	  __exception_ptr::__dest_thunk<_Ex2>);
+      __try
+	{
+	  ::new (__e) _Ex2(__ex);
+	  return exception_ptr(__e);
+	}
+      __catch(...)
+	{
+	  __cxxabiv1::__cxa_free_exception(__e);
+	  return current_exception();
+	}
+#else
+      try
+	{
+          throw __ex;
+	}
+      catch(...)
+	{
+	  return current_exception();
+	}
+#endif
+    }
+#else // no RTTI and no exceptions
+  // This is always_inline so the linker will never use this useless definition
+  // instead of a working one compiled with RTTI and/or exceptions enabled.
+  template<typename _Ex>
+    __attribute__ ((__always_inline__))
+    exception_ptr
+    make_exception_ptr(_Ex) _GLIBCXX_USE_NOEXCEPT
+    { return exception_ptr(); }
+#endif
+
+#undef _GLIBCXX_EH_PTR_USED
+
+  /// @} group exceptions
+} // namespace std
+
+} // extern "C++"
+
+#pragma GCC visibility pop
+
+#endif
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@forward_list.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@forward_list.h
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@@ -0,0 +1,1544 @@
+// <forward_list.h> -*- C++ -*-
+
+// Copyright (C) 2008-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/forward_list.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{forward_list}
+ */
+
+#ifndef _FORWARD_LIST_H
+#define _FORWARD_LIST_H 1
+
+#pragma GCC system_header
+
+#include <initializer_list>
+#include <bits/stl_iterator_base_types.h>
+#include <bits/stl_iterator.h>
+#include <bits/stl_algobase.h>
+#include <bits/stl_function.h>
+#include <bits/allocator.h>
+#include <ext/alloc_traits.h>
+#include <ext/aligned_buffer.h>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+_GLIBCXX_BEGIN_NAMESPACE_CONTAINER
+
+  /**
+   *  @brief  A helper basic node class for %forward_list.
+   *          This is just a linked list with nothing inside it.
+   *          There are purely list shuffling utility methods here.
+   */
+  struct _Fwd_list_node_base
+  {
+    _Fwd_list_node_base() = default;
+    _Fwd_list_node_base(_Fwd_list_node_base&& __x) noexcept
+      : _M_next(__x._M_next)
+    { __x._M_next = nullptr; }
+
+    _Fwd_list_node_base(const _Fwd_list_node_base&) = delete;
+    _Fwd_list_node_base& operator=(const _Fwd_list_node_base&) = delete;
+
+    _Fwd_list_node_base&
+    operator=(_Fwd_list_node_base&& __x) noexcept
+    {
+      _M_next = __x._M_next;
+      __x._M_next = nullptr;
+      return *this;
+    }
+
+    _Fwd_list_node_base* _M_next = nullptr;
+
+    _Fwd_list_node_base*
+    _M_transfer_after(_Fwd_list_node_base* __begin,
+		      _Fwd_list_node_base* __end) noexcept
+    {
+      _Fwd_list_node_base* __keep = __begin->_M_next;
+      if (__end)
+	{
+	  __begin->_M_next = __end->_M_next;
+	  __end->_M_next = _M_next;
+	}
+      else
+	__begin->_M_next = nullptr;
+      _M_next = __keep;
+      return __end;
+    }
+
+    void
+    _M_reverse_after() noexcept
+    {
+      _Fwd_list_node_base* __tail = _M_next;
+      if (!__tail)
+	return;
+      while (_Fwd_list_node_base* __temp = __tail->_M_next)
+	{
+	  _Fwd_list_node_base* __keep = _M_next;
+	  _M_next = __temp;
+	  __tail->_M_next = __temp->_M_next;
+	  _M_next->_M_next = __keep;
+	}
+    }
+  };
+
+  /**
+   *  @brief  A helper node class for %forward_list.
+   *          This is just a linked list with uninitialized storage for a
+   *          data value in each node.
+   *          There is a sorting utility method.
+   */
+  template<typename _Tp>
+    struct _Fwd_list_node
+    : public _Fwd_list_node_base
+    {
+      _Fwd_list_node() = default;
+
+      __gnu_cxx::__aligned_buffer<_Tp> _M_storage;
+
+      _Tp*
+      _M_valptr() noexcept
+      { return _M_storage._M_ptr(); }
+
+      const _Tp*
+      _M_valptr() const noexcept
+      { return _M_storage._M_ptr(); }
+    };
+
+  /**
+   *   @brief A forward_list::iterator.
+   *
+   *   All the functions are op overloads.
+   */
+  template<typename _Tp>
+    struct _Fwd_list_iterator
+    {
+      typedef _Fwd_list_iterator<_Tp>		_Self;
+      typedef _Fwd_list_node<_Tp>		_Node;
+
+      typedef _Tp				value_type;
+      typedef _Tp*				pointer;
+      typedef _Tp&				reference;
+      typedef ptrdiff_t				difference_type;
+      typedef std::forward_iterator_tag		iterator_category;
+
+      _Fwd_list_iterator() noexcept
+      : _M_node() { }
+
+      explicit
+      _Fwd_list_iterator(_Fwd_list_node_base* __n) noexcept
+      : _M_node(__n) { }
+
+      [[__nodiscard__]]
+      reference
+      operator*() const noexcept
+      { return *static_cast<_Node*>(this->_M_node)->_M_valptr(); }
+
+      [[__nodiscard__]]
+      pointer
+      operator->() const noexcept
+      { return static_cast<_Node*>(this->_M_node)->_M_valptr(); }
+
+      _Self&
+      operator++() noexcept
+      {
+	_M_node = _M_node->_M_next;
+	return *this;
+      }
+
+      _Self
+      operator++(int) noexcept
+      {
+	_Self __tmp(*this);
+	_M_node = _M_node->_M_next;
+	return __tmp;
+      }
+
+      /**
+       *  @brief  Forward list iterator equality comparison.
+       */
+      [[__nodiscard__]]
+      friend bool
+      operator==(const _Self& __x, const _Self& __y) noexcept
+      { return __x._M_node == __y._M_node; }
+
+#if __cpp_impl_three_way_comparison < 201907L
+      /**
+       *  @brief  Forward list iterator inequality comparison.
+       */
+      [[__nodiscard__]]
+      friend bool
+      operator!=(const _Self& __x, const _Self& __y) noexcept
+      { return __x._M_node != __y._M_node; }
+#endif
+
+      _Self
+      _M_next() const noexcept
+      {
+	if (_M_node)
+	  return _Fwd_list_iterator(_M_node->_M_next);
+	else
+	  return _Fwd_list_iterator(nullptr);
+      }
+
+      _Fwd_list_node_base* _M_node;
+    };
+
+  /**
+   *   @brief A forward_list::const_iterator.
+   *
+   *   All the functions are op overloads.
+   */
+  template<typename _Tp>
+    struct _Fwd_list_const_iterator
+    {
+      typedef _Fwd_list_const_iterator<_Tp>	_Self;
+      typedef const _Fwd_list_node<_Tp>		_Node;
+      typedef _Fwd_list_iterator<_Tp>		iterator;
+
+      typedef _Tp				value_type;
+      typedef const _Tp*			pointer;
+      typedef const _Tp&			reference;
+      typedef ptrdiff_t				difference_type;
+      typedef std::forward_iterator_tag		iterator_category;
+
+      _Fwd_list_const_iterator() noexcept
+      : _M_node() { }
+
+      explicit
+      _Fwd_list_const_iterator(const _Fwd_list_node_base* __n)  noexcept
+      : _M_node(__n) { }
+
+      _Fwd_list_const_iterator(const iterator& __iter) noexcept
+      : _M_node(__iter._M_node) { }
+
+      [[__nodiscard__]]
+      reference
+      operator*() const noexcept
+      { return *static_cast<_Node*>(this->_M_node)->_M_valptr(); }
+
+      [[__nodiscard__]]
+      pointer
+      operator->() const noexcept
+      { return static_cast<_Node*>(this->_M_node)->_M_valptr(); }
+
+      _Self&
+      operator++() noexcept
+      {
+	_M_node = _M_node->_M_next;
+	return *this;
+      }
+
+      _Self
+      operator++(int) noexcept
+      {
+	_Self __tmp(*this);
+	_M_node = _M_node->_M_next;
+	return __tmp;
+      }
+
+      /**
+       *  @brief  Forward list const_iterator equality comparison.
+       */
+      [[__nodiscard__]]
+      friend bool
+      operator==(const _Self& __x, const _Self& __y) noexcept
+      { return __x._M_node == __y._M_node; }
+
+#if __cpp_impl_three_way_comparison < 201907L
+      /**
+       *  @brief  Forward list const_iterator inequality comparison.
+       */
+      [[__nodiscard__]]
+      friend bool
+      operator!=(const _Self& __x, const _Self& __y) noexcept
+      { return __x._M_node != __y._M_node; }
+#endif
+
+      _Self
+      _M_next() const noexcept
+      {
+	if (this->_M_node)
+	  return _Fwd_list_const_iterator(_M_node->_M_next);
+	else
+	  return _Fwd_list_const_iterator(nullptr);
+      }
+
+      const _Fwd_list_node_base* _M_node;
+    };
+
+  /**
+   *  @brief  Base class for %forward_list.
+   */
+  template<typename _Tp, typename _Alloc>
+    struct _Fwd_list_base
+    {
+    protected:
+      typedef __alloc_rebind<_Alloc, _Fwd_list_node<_Tp>> _Node_alloc_type;
+      typedef __gnu_cxx::__alloc_traits<_Node_alloc_type> _Node_alloc_traits;
+
+      struct _Fwd_list_impl
+      : public _Node_alloc_type
+      {
+	_Fwd_list_node_base _M_head;
+
+	_Fwd_list_impl()
+	  noexcept(is_nothrow_default_constructible<_Node_alloc_type>::value)
+	: _Node_alloc_type(), _M_head()
+	{ }
+
+	_Fwd_list_impl(_Fwd_list_impl&&) = default;
+
+	_Fwd_list_impl(_Fwd_list_impl&& __fl, _Node_alloc_type&& __a)
+	: _Node_alloc_type(std::move(__a)), _M_head(std::move(__fl._M_head))
+	{ }
+
+	_Fwd_list_impl(_Node_alloc_type&& __a)
+	: _Node_alloc_type(std::move(__a)), _M_head()
+	{ }
+      };
+
+      _Fwd_list_impl _M_impl;
+
+    public:
+      typedef _Fwd_list_iterator<_Tp>		iterator;
+      typedef _Fwd_list_const_iterator<_Tp>	const_iterator;
+      typedef _Fwd_list_node<_Tp>		_Node;
+
+      _Node_alloc_type&
+      _M_get_Node_allocator() noexcept
+      { return this->_M_impl; }
+
+      const _Node_alloc_type&
+      _M_get_Node_allocator() const noexcept
+      { return this->_M_impl; }
+
+      _Fwd_list_base() = default;
+
+      _Fwd_list_base(_Node_alloc_type&& __a)
+      : _M_impl(std::move(__a)) { }
+
+      // When allocators are always equal.
+      _Fwd_list_base(_Fwd_list_base&& __lst, _Node_alloc_type&& __a,
+		     std::true_type)
+      : _M_impl(std::move(__lst._M_impl), std::move(__a))
+      { }
+
+      // When allocators are not always equal.
+      _Fwd_list_base(_Fwd_list_base&& __lst, _Node_alloc_type&& __a);
+
+      _Fwd_list_base(_Fwd_list_base&&) = default;
+
+      ~_Fwd_list_base()
+      { _M_erase_after(&_M_impl._M_head, nullptr); }
+
+    protected:
+      _Node*
+      _M_get_node()
+      {
+	auto __ptr = _Node_alloc_traits::allocate(_M_get_Node_allocator(), 1);
+	return std::__to_address(__ptr);
+      }
+
+      template<typename... _Args>
+	_Node*
+	_M_create_node(_Args&&... __args)
+	{
+	  _Node* __node = this->_M_get_node();
+	  __try
+	    {
+	      ::new ((void*)__node) _Node;
+	      _Node_alloc_traits::construct(_M_get_Node_allocator(),
+					    __node->_M_valptr(),
+					    std::forward<_Args>(__args)...);
+	    }
+	  __catch(...)
+	    {
+	      this->_M_put_node(__node);
+	      __throw_exception_again;
+	    }
+	  return __node;
+	}
+
+      template<typename... _Args>
+	_Fwd_list_node_base*
+	_M_insert_after(const_iterator __pos, _Args&&... __args);
+
+      void
+      _M_put_node(_Node* __p)
+      {
+	typedef typename _Node_alloc_traits::pointer _Ptr;
+	auto __ptr = std::pointer_traits<_Ptr>::pointer_to(*__p);
+	_Node_alloc_traits::deallocate(_M_get_Node_allocator(), __ptr, 1);
+      }
+
+      _Fwd_list_node_base*
+      _M_erase_after(_Fwd_list_node_base* __pos);
+
+      _Fwd_list_node_base*
+      _M_erase_after(_Fwd_list_node_base* __pos,
+		     _Fwd_list_node_base* __last);
+    };
+
+  /**
+   *  @brief A standard container with linear time access to elements,
+   *  and fixed time insertion/deletion at any point in the sequence.
+   *
+   *  @ingroup sequences
+   *
+   *  @tparam _Tp  Type of element.
+   *  @tparam _Alloc  Allocator type, defaults to allocator<_Tp>.
+   *
+   *  Meets the requirements of a <a href="tables.html#65">container</a>, a
+   *  <a href="tables.html#67">sequence</a>, including the
+   *  <a href="tables.html#68">optional sequence requirements</a> with the
+   *  %exception of @c at and @c operator[].
+   *
+   *  This is a @e singly @e linked %list.  Traversal up the
+   *  %list requires linear time, but adding and removing elements (or
+   *  @e nodes) is done in constant time, regardless of where the
+   *  change takes place.  Unlike std::vector and std::deque,
+   *  random-access iterators are not provided, so subscripting ( @c
+   *  [] ) access is not allowed.  For algorithms which only need
+   *  sequential access, this lack makes no difference.
+   *
+   *  Also unlike the other standard containers, std::forward_list provides
+   *  specialized algorithms %unique to linked lists, such as
+   *  splicing, sorting, and in-place reversal.
+   */
+  template<typename _Tp, typename _Alloc = allocator<_Tp>>
+    class forward_list : private _Fwd_list_base<_Tp, _Alloc>
+    {
+      static_assert(is_same<typename remove_cv<_Tp>::type, _Tp>::value,
+	  "std::forward_list must have a non-const, non-volatile value_type");
+#if __cplusplus > 201703L || defined __STRICT_ANSI__
+      static_assert(is_same<typename _Alloc::value_type, _Tp>::value,
+	  "std::forward_list must have the same value_type as its allocator");
+#endif
+
+    private:
+      typedef _Fwd_list_base<_Tp, _Alloc>		_Base;
+      typedef _Fwd_list_node_base			_Node_base;
+      typedef typename _Base::_Node			_Node;
+      typedef typename _Base::_Node_alloc_type		_Node_alloc_type;
+      typedef typename _Base::_Node_alloc_traits	_Node_alloc_traits;
+      typedef allocator_traits<__alloc_rebind<_Alloc, _Tp>>	_Alloc_traits;
+
+    public:
+      // types:
+      typedef _Tp					value_type;
+      typedef typename _Alloc_traits::pointer		pointer;
+      typedef typename _Alloc_traits::const_pointer	const_pointer;
+      typedef value_type&				reference;
+      typedef const value_type&				const_reference;
+
+      typedef typename _Base::iterator			iterator;
+      typedef typename _Base::const_iterator		const_iterator;
+      typedef std::size_t				size_type;
+      typedef std::ptrdiff_t				difference_type;
+      typedef _Alloc					allocator_type;
+
+      // 23.3.4.2 construct/copy/destroy:
+
+      /**
+       *  @brief  Creates a %forward_list with no elements.
+       */
+      forward_list() = default;
+
+      /**
+       *  @brief  Creates a %forward_list with no elements.
+       *  @param  __al  An allocator object.
+       */
+      explicit
+      forward_list(const _Alloc& __al) noexcept
+      : _Base(_Node_alloc_type(__al))
+      { }
+
+      /**
+       *  @brief  Copy constructor with allocator argument.
+       *  @param  __list  Input list to copy.
+       *  @param  __al    An allocator object.
+       */
+      forward_list(const forward_list& __list,
+		   const __type_identity_t<_Alloc>& __al)
+      : _Base(_Node_alloc_type(__al))
+      { _M_range_initialize(__list.begin(), __list.end()); }
+
+    private:
+      forward_list(forward_list&& __list, _Node_alloc_type&& __al,
+		   false_type)
+      : _Base(std::move(__list), std::move(__al))
+      {
+	// If __list is not empty it means its allocator is not equal to __a,
+	// so we need to move from each element individually.
+	insert_after(cbefore_begin(),
+		     std::__make_move_if_noexcept_iterator(__list.begin()),
+		     std::__make_move_if_noexcept_iterator(__list.end()));
+      }
+
+      forward_list(forward_list&& __list, _Node_alloc_type&& __al,
+		   true_type)
+      noexcept
+      : _Base(std::move(__list), _Node_alloc_type(__al), true_type{})
+      { }
+
+    public:
+      /**
+       *  @brief  Move constructor with allocator argument.
+       *  @param  __list  Input list to move.
+       *  @param  __al    An allocator object.
+       */
+      forward_list(forward_list&& __list,
+		   const __type_identity_t<_Alloc>& __al)
+      noexcept(_Node_alloc_traits::_S_always_equal())
+      : forward_list(std::move(__list), _Node_alloc_type(__al),
+		     typename _Node_alloc_traits::is_always_equal{})
+      { }
+
+      /**
+       *  @brief  Creates a %forward_list with default constructed elements.
+       *  @param  __n   The number of elements to initially create.
+       *  @param  __al  An allocator object.
+       *
+       *  This constructor creates the %forward_list with @a __n default
+       *  constructed elements.
+       */
+      explicit
+      forward_list(size_type __n, const _Alloc& __al = _Alloc())
+      : _Base(_Node_alloc_type(__al))
+      { _M_default_initialize(__n); }
+
+      /**
+       *  @brief  Creates a %forward_list with copies of an exemplar element.
+       *  @param  __n      The number of elements to initially create.
+       *  @param  __value  An element to copy.
+       *  @param  __al     An allocator object.
+       *
+       *  This constructor fills the %forward_list with @a __n copies of
+       *  @a __value.
+       */
+      forward_list(size_type __n, const _Tp& __value,
+		   const _Alloc& __al = _Alloc())
+      : _Base(_Node_alloc_type(__al))
+      { _M_fill_initialize(__n, __value); }
+
+      /**
+       *  @brief  Builds a %forward_list from a range.
+       *  @param  __first  An input iterator.
+       *  @param  __last   An input iterator.
+       *  @param  __al     An allocator object.
+       *
+       *  Create a %forward_list consisting of copies of the elements from
+       *  [@a __first,@a __last).  This is linear in N (where N is
+       *  distance(@a __first,@a __last)).
+       */
+      template<typename _InputIterator,
+	       typename = std::_RequireInputIter<_InputIterator>>
+	forward_list(_InputIterator __first, _InputIterator __last,
+		     const _Alloc& __al = _Alloc())
+	: _Base(_Node_alloc_type(__al))
+	{ _M_range_initialize(__first, __last); }
+
+      /**
+       *  @brief  The %forward_list copy constructor.
+       *  @param  __list  A %forward_list of identical element and allocator
+       *                  types.
+       */
+      forward_list(const forward_list& __list)
+      : _Base(_Node_alloc_traits::_S_select_on_copy(
+		__list._M_get_Node_allocator()))
+      { _M_range_initialize(__list.begin(), __list.end()); }
+
+      /**
+       *  @brief  The %forward_list move constructor.
+       *  @param  __list  A %forward_list of identical element and allocator
+       *                  types.
+       *
+       *  The newly-created %forward_list contains the exact contents of the
+       *  moved instance. The contents of the moved instance are a valid, but
+       *  unspecified %forward_list.
+       */
+      forward_list(forward_list&&) = default;
+
+      /**
+       *  @brief  Builds a %forward_list from an initializer_list
+       *  @param  __il  An initializer_list of value_type.
+       *  @param  __al  An allocator object.
+       *
+       *  Create a %forward_list consisting of copies of the elements
+       *  in the initializer_list @a __il.  This is linear in __il.size().
+       */
+      forward_list(std::initializer_list<_Tp> __il,
+		   const _Alloc& __al = _Alloc())
+      : _Base(_Node_alloc_type(__al))
+      { _M_range_initialize(__il.begin(), __il.end()); }
+
+      /**
+       *  @brief  The forward_list dtor.
+       */
+      ~forward_list() noexcept
+      { }
+
+      /**
+       *  @brief  The %forward_list assignment operator.
+       *  @param  __list  A %forward_list of identical element and allocator
+       *                types.
+       *
+       *  All the elements of @a __list are copied.
+       *
+       *  Whether the allocator is copied depends on the allocator traits.
+       */
+      forward_list&
+      operator=(const forward_list& __list);
+
+      /**
+       *  @brief  The %forward_list move assignment operator.
+       *  @param  __list  A %forward_list of identical element and allocator
+       *                types.
+       *
+       *  The contents of @a __list are moved into this %forward_list
+       *  (without copying, if the allocators permit it).
+       *
+       *  Afterwards @a __list is a valid, but unspecified %forward_list
+       *
+       *  Whether the allocator is moved depends on the allocator traits.
+       */
+      forward_list&
+      operator=(forward_list&& __list)
+      noexcept(_Node_alloc_traits::_S_nothrow_move())
+      {
+	constexpr bool __move_storage =
+	  _Node_alloc_traits::_S_propagate_on_move_assign()
+	  || _Node_alloc_traits::_S_always_equal();
+	_M_move_assign(std::move(__list), __bool_constant<__move_storage>());
+	return *this;
+      }
+
+      /**
+       *  @brief  The %forward_list initializer list assignment operator.
+       *  @param  __il  An initializer_list of value_type.
+       *
+       *  Replace the contents of the %forward_list with copies of the
+       *  elements in the initializer_list @a __il.  This is linear in
+       *  __il.size().
+       */
+      forward_list&
+      operator=(std::initializer_list<_Tp> __il)
+      {
+	assign(__il);
+	return *this;
+      }
+
+      /**
+       *  @brief  Assigns a range to a %forward_list.
+       *  @param  __first  An input iterator.
+       *  @param  __last   An input iterator.
+       *
+       *  This function fills a %forward_list with copies of the elements
+       *  in the range [@a __first,@a __last).
+       *
+       *  Note that the assignment completely changes the %forward_list and
+       *  that the number of elements of the resulting %forward_list is the
+       *  same as the number of elements assigned.
+       */
+      template<typename _InputIterator,
+	       typename = std::_RequireInputIter<_InputIterator>>
+	void
+	assign(_InputIterator __first, _InputIterator __last)
+	{
+	  typedef is_assignable<_Tp, decltype(*__first)> __assignable;
+	  _M_assign(__first, __last, __assignable());
+	}
+
+      /**
+       *  @brief  Assigns a given value to a %forward_list.
+       *  @param  __n  Number of elements to be assigned.
+       *  @param  __val  Value to be assigned.
+       *
+       *  This function fills a %forward_list with @a __n copies of the
+       *  given value.  Note that the assignment completely changes the
+       *  %forward_list, and that the resulting %forward_list has __n
+       *  elements.
+       */
+      void
+      assign(size_type __n, const _Tp& __val)
+      { _M_assign_n(__n, __val, is_copy_assignable<_Tp>()); }
+
+      /**
+       *  @brief  Assigns an initializer_list to a %forward_list.
+       *  @param  __il  An initializer_list of value_type.
+       *
+       *  Replace the contents of the %forward_list with copies of the
+       *  elements in the initializer_list @a __il.  This is linear in
+       *  il.size().
+       */
+      void
+      assign(std::initializer_list<_Tp> __il)
+      { assign(__il.begin(), __il.end()); }
+
+      /// Get a copy of the memory allocation object.
+      allocator_type
+      get_allocator() const noexcept
+      { return allocator_type(this->_M_get_Node_allocator()); }
+
+      // 23.3.4.3 iterators:
+
+      /**
+       *  Returns a read/write iterator that points before the first element
+       *  in the %forward_list.  Iteration is done in ordinary element order.
+       */
+      [[__nodiscard__]]
+      iterator
+      before_begin() noexcept
+      { return iterator(&this->_M_impl._M_head); }
+
+      /**
+       *  Returns a read-only (constant) iterator that points before the
+       *  first element in the %forward_list.  Iteration is done in ordinary
+       *  element order.
+       */
+      [[__nodiscard__]]
+      const_iterator
+      before_begin() const noexcept
+      { return const_iterator(&this->_M_impl._M_head); }
+
+      /**
+       *  Returns a read/write iterator that points to the first element
+       *  in the %forward_list.  Iteration is done in ordinary element order.
+       */
+      [[__nodiscard__]]
+      iterator
+      begin() noexcept
+      { return iterator(this->_M_impl._M_head._M_next); }
+
+      /**
+       *  Returns a read-only (constant) iterator that points to the first
+       *  element in the %forward_list.  Iteration is done in ordinary
+       *  element order.
+       */
+      [[__nodiscard__]]
+      const_iterator
+      begin() const noexcept
+      { return const_iterator(this->_M_impl._M_head._M_next); }
+
+      /**
+       *  Returns a read/write iterator that points one past the last
+       *  element in the %forward_list.  Iteration is done in ordinary
+       *  element order.
+       */
+      [[__nodiscard__]]
+      iterator
+      end() noexcept
+      { return iterator(nullptr); }
+
+      /**
+       *  Returns a read-only iterator that points one past the last
+       *  element in the %forward_list.  Iteration is done in ordinary
+       *  element order.
+       */
+      [[__nodiscard__]]
+      const_iterator
+      end() const noexcept
+      { return const_iterator(nullptr); }
+
+      /**
+       *  Returns a read-only (constant) iterator that points to the
+       *  first element in the %forward_list.  Iteration is done in ordinary
+       *  element order.
+       */
+      [[__nodiscard__]]
+      const_iterator
+      cbegin() const noexcept
+      { return const_iterator(this->_M_impl._M_head._M_next); }
+
+      /**
+       *  Returns a read-only (constant) iterator that points before the
+       *  first element in the %forward_list.  Iteration is done in ordinary
+       *  element order.
+       */
+      [[__nodiscard__]]
+      const_iterator
+      cbefore_begin() const noexcept
+      { return const_iterator(&this->_M_impl._M_head); }
+
+      /**
+       *  Returns a read-only (constant) iterator that points one past
+       *  the last element in the %forward_list.  Iteration is done in
+       *  ordinary element order.
+       */
+      [[__nodiscard__]]
+      const_iterator
+      cend() const noexcept
+      { return const_iterator(nullptr); }
+
+      /**
+       *  Returns true if the %forward_list is empty.  (Thus begin() would
+       *  equal end().)
+       */
+      [[__nodiscard__]]
+      bool
+      empty() const noexcept
+      { return this->_M_impl._M_head._M_next == nullptr; }
+
+      /**
+       *  Returns the largest possible number of elements of %forward_list.
+       */
+      [[__nodiscard__]]
+      size_type
+      max_size() const noexcept
+      { return _Node_alloc_traits::max_size(this->_M_get_Node_allocator()); }
+
+      // 23.3.4.4 element access:
+
+      /**
+       *  Returns a read/write reference to the data at the first
+       *  element of the %forward_list.
+       */
+      [[__nodiscard__]]
+      reference
+      front()
+      {
+	_Node* __front = static_cast<_Node*>(this->_M_impl._M_head._M_next);
+	return *__front->_M_valptr();
+      }
+
+      /**
+       *  Returns a read-only (constant) reference to the data at the first
+       *  element of the %forward_list.
+       */
+      [[__nodiscard__]]
+      const_reference
+      front() const
+      {
+	_Node* __front = static_cast<_Node*>(this->_M_impl._M_head._M_next);
+	return *__front->_M_valptr();
+      }
+
+      // 23.3.4.5 modifiers:
+
+      /**
+       *  @brief  Constructs object in %forward_list at the front of the
+       *          list.
+       *  @param  __args  Arguments.
+       *
+       *  This function will insert an object of type Tp constructed
+       *  with Tp(std::forward<Args>(args)...) at the front of the list
+       *  Due to the nature of a %forward_list this operation can
+       *  be done in constant time, and does not invalidate iterators
+       *  and references.
+       */
+      template<typename... _Args>
+#if __cplusplus > 201402L
+	reference
+#else
+	void
+#endif
+	emplace_front(_Args&&... __args)
+	{
+	  this->_M_insert_after(cbefore_begin(),
+				std::forward<_Args>(__args)...);
+#if __cplusplus > 201402L
+	  return front();
+#endif
+	}
+
+      /**
+       *  @brief  Add data to the front of the %forward_list.
+       *  @param  __val  Data to be added.
+       *
+       *  This is a typical stack operation.  The function creates an
+       *  element at the front of the %forward_list and assigns the given
+       *  data to it.  Due to the nature of a %forward_list this operation
+       *  can be done in constant time, and does not invalidate iterators
+       *  and references.
+       */
+      void
+      push_front(const _Tp& __val)
+      { this->_M_insert_after(cbefore_begin(), __val); }
+
+      /**
+       *
+       */
+      void
+      push_front(_Tp&& __val)
+      { this->_M_insert_after(cbefore_begin(), std::move(__val)); }
+
+      /**
+       *  @brief  Removes first element.
+       *
+       *  This is a typical stack operation.  It shrinks the %forward_list
+       *  by one.  Due to the nature of a %forward_list this operation can
+       *  be done in constant time, and only invalidates iterators/references
+       *  to the element being removed.
+       *
+       *  Note that no data is returned, and if the first element's data
+       *  is needed, it should be retrieved before pop_front() is
+       *  called.
+       */
+      void
+      pop_front()
+      { this->_M_erase_after(&this->_M_impl._M_head); }
+
+      /**
+       *  @brief  Constructs object in %forward_list after the specified
+       *          iterator.
+       *  @param  __pos  A const_iterator into the %forward_list.
+       *  @param  __args  Arguments.
+       *  @return  An iterator that points to the inserted data.
+       *
+       *  This function will insert an object of type T constructed
+       *  with T(std::forward<Args>(args)...) after the specified
+       *  location.  Due to the nature of a %forward_list this operation can
+       *  be done in constant time, and does not invalidate iterators
+       *  and references.
+       */
+      template<typename... _Args>
+	iterator
+	emplace_after(const_iterator __pos, _Args&&... __args)
+	{ return iterator(this->_M_insert_after(__pos,
+					  std::forward<_Args>(__args)...)); }
+
+      /**
+       *  @brief  Inserts given value into %forward_list after specified
+       *          iterator.
+       *  @param  __pos  An iterator into the %forward_list.
+       *  @param  __val  Data to be inserted.
+       *  @return  An iterator that points to the inserted data.
+       *
+       *  This function will insert a copy of the given value after
+       *  the specified location.  Due to the nature of a %forward_list this
+       *  operation can be done in constant time, and does not
+       *  invalidate iterators and references.
+       */
+      iterator
+      insert_after(const_iterator __pos, const _Tp& __val)
+      { return iterator(this->_M_insert_after(__pos, __val)); }
+
+      /**
+       *
+       */
+      iterator
+      insert_after(const_iterator __pos, _Tp&& __val)
+      { return iterator(this->_M_insert_after(__pos, std::move(__val))); }
+
+      /**
+       *  @brief  Inserts a number of copies of given data into the
+       *          %forward_list.
+       *  @param  __pos  An iterator into the %forward_list.
+       *  @param  __n  Number of elements to be inserted.
+       *  @param  __val  Data to be inserted.
+       *  @return  An iterator pointing to the last inserted copy of
+       *           @a val or @a pos if @a n == 0.
+       *
+       *  This function will insert a specified number of copies of the
+       *  given data after the location specified by @a pos.
+       *
+       *  This operation is linear in the number of elements inserted and
+       *  does not invalidate iterators and references.
+       */
+      iterator
+      insert_after(const_iterator __pos, size_type __n, const _Tp& __val);
+
+      /**
+       *  @brief  Inserts a range into the %forward_list.
+       *  @param  __pos  An iterator into the %forward_list.
+       *  @param  __first  An input iterator.
+       *  @param  __last   An input iterator.
+       *  @return  An iterator pointing to the last inserted element or
+       *           @a __pos if @a __first == @a __last.
+       *
+       *  This function will insert copies of the data in the range
+       *  [@a __first,@a __last) into the %forward_list after the
+       *  location specified by @a __pos.
+       *
+       *  This operation is linear in the number of elements inserted and
+       *  does not invalidate iterators and references.
+       */
+      template<typename _InputIterator,
+	       typename = std::_RequireInputIter<_InputIterator>>
+	iterator
+	insert_after(const_iterator __pos,
+		     _InputIterator __first, _InputIterator __last);
+
+      /**
+       *  @brief  Inserts the contents of an initializer_list into
+       *          %forward_list after the specified iterator.
+       *  @param  __pos  An iterator into the %forward_list.
+       *  @param  __il  An initializer_list of value_type.
+       *  @return  An iterator pointing to the last inserted element
+       *           or @a __pos if @a __il is empty.
+       *
+       *  This function will insert copies of the data in the
+       *  initializer_list @a __il into the %forward_list before the location
+       *  specified by @a __pos.
+       *
+       *  This operation is linear in the number of elements inserted and
+       *  does not invalidate iterators and references.
+       */
+      iterator
+      insert_after(const_iterator __pos, std::initializer_list<_Tp> __il)
+      { return insert_after(__pos, __il.begin(), __il.end()); }
+
+      /**
+       *  @brief  Removes the element pointed to by the iterator following
+       *          @c pos.
+       *  @param  __pos  Iterator pointing before element to be erased.
+       *  @return  An iterator pointing to the element following the one
+       *           that was erased, or end() if no such element exists.
+       *
+       *  This function will erase the element at the given position and
+       *  thus shorten the %forward_list by one.
+       *
+       *  Due to the nature of a %forward_list this operation can be done
+       *  in constant time, and only invalidates iterators/references to
+       *  the element being removed.  The user is also cautioned that
+       *  this function only erases the element, and that if the element
+       *  is itself a pointer, the pointed-to memory is not touched in
+       *  any way.  Managing the pointer is the user's responsibility.
+       */
+      iterator
+      erase_after(const_iterator __pos)
+      { return iterator(this->_M_erase_after(const_cast<_Node_base*>
+					     (__pos._M_node))); }
+
+      /**
+       *  @brief  Remove a range of elements.
+       *  @param  __pos  Iterator pointing before the first element to be
+       *                 erased.
+       *  @param  __last  Iterator pointing to one past the last element to be
+       *                  erased.
+       *  @return  @ __last.
+       *
+       *  This function will erase the elements in the range
+       *  @a (__pos,__last) and shorten the %forward_list accordingly.
+       *
+       *  This operation is linear time in the size of the range and only
+       *  invalidates iterators/references to the element being removed.
+       *  The user is also cautioned that this function only erases the
+       *  elements, and that if the elements themselves are pointers, the
+       *  pointed-to memory is not touched in any way.  Managing the pointer
+       *  is the user's responsibility.
+       */
+      iterator
+      erase_after(const_iterator __pos, const_iterator __last)
+      { return iterator(this->_M_erase_after(const_cast<_Node_base*>
+					     (__pos._M_node),
+					     const_cast<_Node_base*>
+					     (__last._M_node))); }
+
+      /**
+       *  @brief  Swaps data with another %forward_list.
+       *  @param  __list  A %forward_list of the same element and allocator
+       *                  types.
+       *
+       *  This exchanges the elements between two lists in constant
+       *  time.  Note that the global std::swap() function is
+       *  specialized such that std::swap(l1,l2) will feed to this
+       *  function.
+       *
+       *  Whether the allocators are swapped depends on the allocator traits.
+       */
+      void
+      swap(forward_list& __list) noexcept
+      {
+	std::swap(this->_M_impl._M_head._M_next,
+		  __list._M_impl._M_head._M_next);
+	_Node_alloc_traits::_S_on_swap(this->_M_get_Node_allocator(),
+				       __list._M_get_Node_allocator());
+      }
+
+      /**
+       *  @brief Resizes the %forward_list to the specified number of
+       *         elements.
+       *  @param __sz Number of elements the %forward_list should contain.
+       *
+       *  This function will %resize the %forward_list to the specified
+       *  number of elements.  If the number is smaller than the
+       *  %forward_list's current number of elements the %forward_list
+       *  is truncated, otherwise the %forward_list is extended and the
+       *  new elements are default constructed.
+       */
+      void
+      resize(size_type __sz);
+
+      /**
+       *  @brief Resizes the %forward_list to the specified number of
+       *         elements.
+       *  @param __sz Number of elements the %forward_list should contain.
+       *  @param __val Data with which new elements should be populated.
+       *
+       *  This function will %resize the %forward_list to the specified
+       *  number of elements.  If the number is smaller than the
+       *  %forward_list's current number of elements the %forward_list
+       *  is truncated, otherwise the %forward_list is extended and new
+       *  elements are populated with given data.
+       */
+      void
+      resize(size_type __sz, const value_type& __val);
+
+      /**
+       *  @brief  Erases all the elements.
+       *
+       *  Note that this function only erases
+       *  the elements, and that if the elements themselves are
+       *  pointers, the pointed-to memory is not touched in any way.
+       *  Managing the pointer is the user's responsibility.
+       */
+      void
+      clear() noexcept
+      { this->_M_erase_after(&this->_M_impl._M_head, nullptr); }
+
+      // 23.3.4.6 forward_list operations:
+
+      /**
+       *  @brief  Insert contents of another %forward_list.
+       *  @param  __pos  Iterator referencing the element to insert after.
+       *  @param  __list  Source list.
+       *
+       *  The elements of @a list are inserted in constant time after
+       *  the element referenced by @a pos.  @a list becomes an empty
+       *  list.
+       *
+       *  Requires this != @a x.
+       */
+      void
+      splice_after(const_iterator __pos, forward_list&& __list) noexcept
+      {
+	if (!__list.empty())
+	  _M_splice_after(__pos, __list.before_begin(), __list.end());
+      }
+
+      void
+      splice_after(const_iterator __pos, forward_list& __list) noexcept
+      { splice_after(__pos, std::move(__list)); }
+
+      /**
+       *  @brief  Insert element from another %forward_list.
+       *  @param  __pos  Iterator referencing the element to insert after.
+       *  @param  __list  Source list.
+       *  @param  __i   Iterator referencing the element before the element
+       *                to move.
+       *
+       *  Removes the element in list @a list referenced by @a i and
+       *  inserts it into the current list after @a pos.
+       */
+      void
+      splice_after(const_iterator __pos, forward_list&& __list,
+		   const_iterator __i) noexcept;
+
+      void
+      splice_after(const_iterator __pos, forward_list& __list,
+		   const_iterator __i) noexcept
+      { splice_after(__pos, std::move(__list), __i); }
+
+      /**
+       *  @brief  Insert range from another %forward_list.
+       *  @param  __pos  Iterator referencing the element to insert after.
+       *  @param  __list  Source list.
+       *  @param  __before  Iterator referencing before the start of range
+       *                    in list.
+       *  @param  __last  Iterator referencing the end of range in list.
+       *
+       *  Removes elements in the range (__before,__last) and inserts them
+       *  after @a __pos in constant time.
+       *
+       *  Undefined if @a __pos is in (__before,__last).
+       *  @{
+       */
+      void
+      splice_after(const_iterator __pos, forward_list&&,
+		   const_iterator __before, const_iterator __last) noexcept
+      { _M_splice_after(__pos, __before, __last); }
+
+      void
+      splice_after(const_iterator __pos, forward_list&,
+		   const_iterator __before, const_iterator __last) noexcept
+      { _M_splice_after(__pos, __before, __last); }
+      /// @}
+
+    private:
+#if __cplusplus > 201703L
+# define __cpp_lib_list_remove_return_type 201806L
+      using __remove_return_type = size_type;
+# define _GLIBCXX_FWDLIST_REMOVE_RETURN_TYPE_TAG \
+      __attribute__((__abi_tag__("__cxx20")))
+#else
+      using __remove_return_type = void;
+# define _GLIBCXX_FWDLIST_REMOVE_RETURN_TYPE_TAG
+#endif
+    public:
+
+      /**
+       *  @brief  Remove all elements equal to value.
+       *  @param  __val  The value to remove.
+       *
+       *  Removes every element in the list equal to @a __val.
+       *  Remaining elements stay in list order.  Note that this
+       *  function only erases the elements, and that if the elements
+       *  themselves are pointers, the pointed-to memory is not
+       *  touched in any way.  Managing the pointer is the user's
+       *  responsibility.
+       */
+      _GLIBCXX_FWDLIST_REMOVE_RETURN_TYPE_TAG
+      __remove_return_type
+      remove(const _Tp& __val);
+
+      /**
+       *  @brief  Remove all elements satisfying a predicate.
+       *  @param  __pred  Unary predicate function or object.
+       *
+       *  Removes every element in the list for which the predicate
+       *  returns true.  Remaining elements stay in list order.  Note
+       *  that this function only erases the elements, and that if the
+       *  elements themselves are pointers, the pointed-to memory is
+       *  not touched in any way.  Managing the pointer is the user's
+       *  responsibility.
+       */
+      template<typename _Pred>
+	__remove_return_type
+	remove_if(_Pred __pred);
+
+      /**
+       *  @brief  Remove consecutive duplicate elements.
+       *
+       *  For each consecutive set of elements with the same value,
+       *  remove all but the first one.  Remaining elements stay in
+       *  list order.  Note that this function only erases the
+       *  elements, and that if the elements themselves are pointers,
+       *  the pointed-to memory is not touched in any way.  Managing
+       *  the pointer is the user's responsibility.
+       */
+      _GLIBCXX_FWDLIST_REMOVE_RETURN_TYPE_TAG
+      __remove_return_type
+      unique()
+      { return unique(std::equal_to<_Tp>()); }
+
+#undef _GLIBCXX_FWDLIST_REMOVE_RETURN_TYPE_TAG
+
+      /**
+       *  @brief  Remove consecutive elements satisfying a predicate.
+       *  @param  __binary_pred  Binary predicate function or object.
+       *
+       *  For each consecutive set of elements [first,last) that
+       *  satisfy predicate(first,i) where i is an iterator in
+       *  [first,last), remove all but the first one.  Remaining
+       *  elements stay in list order.  Note that this function only
+       *  erases the elements, and that if the elements themselves are
+       *  pointers, the pointed-to memory is not touched in any way.
+       *  Managing the pointer is the user's responsibility.
+       */
+      template<typename _BinPred>
+	__remove_return_type
+	unique(_BinPred __binary_pred);
+
+      /**
+       *  @brief  Merge sorted lists.
+       *  @param  __list  Sorted list to merge.
+       *
+       *  Assumes that both @a list and this list are sorted according to
+       *  operator<().  Merges elements of @a __list into this list in
+       *  sorted order, leaving @a __list empty when complete.  Elements in
+       *  this list precede elements in @a __list that are equal.
+       */
+      void
+      merge(forward_list&& __list)
+      { merge(std::move(__list), std::less<_Tp>()); }
+
+      void
+      merge(forward_list& __list)
+      { merge(std::move(__list)); }
+
+      /**
+       *  @brief  Merge sorted lists according to comparison function.
+       *  @param  __list  Sorted list to merge.
+       *  @param  __comp Comparison function defining sort order.
+       *
+       *  Assumes that both @a __list and this list are sorted according to
+       *  comp.  Merges elements of @a __list into this list
+       *  in sorted order, leaving @a __list empty when complete.  Elements
+       *  in this list precede elements in @a __list that are equivalent
+       *  according to comp().
+       */
+      template<typename _Comp>
+	void
+	merge(forward_list&& __list, _Comp __comp);
+
+      template<typename _Comp>
+	void
+	merge(forward_list& __list, _Comp __comp)
+	{ merge(std::move(__list), __comp); }
+
+      /**
+       *  @brief  Sort the elements of the list.
+       *
+       *  Sorts the elements of this list in NlogN time.  Equivalent
+       *  elements remain in list order.
+       */
+      void
+      sort()
+      { sort(std::less<_Tp>()); }
+
+      /**
+       *  @brief  Sort the forward_list using a comparison function.
+       *
+       *  Sorts the elements of this list in NlogN time.  Equivalent
+       *  elements remain in list order.
+       */
+      template<typename _Comp>
+	void
+	sort(_Comp __comp);
+
+      /**
+       *  @brief  Reverse the elements in list.
+       *
+       *  Reverse the order of elements in the list in linear time.
+       */
+      void
+      reverse() noexcept
+      { this->_M_impl._M_head._M_reverse_after(); }
+
+    private:
+      // Called by the range constructor to implement [23.3.4.2]/9
+      template<typename _InputIterator>
+	void
+	_M_range_initialize(_InputIterator __first, _InputIterator __last);
+
+      // Called by forward_list(n,v,a), and the range constructor when it
+      // turns out to be the same thing.
+      void
+      _M_fill_initialize(size_type __n, const value_type& __value);
+
+      // Called by splice_after and insert_after.
+      iterator
+      _M_splice_after(const_iterator __pos, const_iterator __before,
+		      const_iterator __last);
+
+      // Called by forward_list(n).
+      void
+      _M_default_initialize(size_type __n);
+
+      // Called by resize(sz).
+      void
+      _M_default_insert_after(const_iterator __pos, size_type __n);
+
+      // Called by operator=(forward_list&&)
+      void
+      _M_move_assign(forward_list&& __list, true_type) noexcept
+      {
+	clear();
+	this->_M_impl._M_head._M_next = __list._M_impl._M_head._M_next;
+	__list._M_impl._M_head._M_next = nullptr;
+	std::__alloc_on_move(this->_M_get_Node_allocator(),
+			     __list._M_get_Node_allocator());
+      }
+
+      // Called by operator=(forward_list&&)
+      void
+      _M_move_assign(forward_list&& __list, false_type)
+      {
+	if (__list._M_get_Node_allocator() == this->_M_get_Node_allocator())
+	  _M_move_assign(std::move(__list), true_type());
+	else
+	  // The rvalue's allocator cannot be moved, or is not equal,
+	  // so we need to individually move each element.
+	  this->assign(std::make_move_iterator(__list.begin()),
+		       std::make_move_iterator(__list.end()));
+      }
+
+      // Called by assign(_InputIterator, _InputIterator) if _Tp is
+      // CopyAssignable.
+      template<typename _InputIterator>
+	void
+	_M_assign(_InputIterator __first, _InputIterator __last, true_type)
+	{
+	  auto __prev = before_begin();
+	  auto __curr = begin();
+	  auto __end = end();
+	  while (__curr != __end && __first != __last)
+	    {
+	      *__curr = *__first;
+	      ++__prev;
+	      ++__curr;
+	      ++__first;
+	    }
+	  if (__first != __last)
+	    insert_after(__prev, __first, __last);
+	  else if (__curr != __end)
+	    erase_after(__prev, __end);
+	}
+
+      // Called by assign(_InputIterator, _InputIterator) if _Tp is not
+      // CopyAssignable.
+      template<typename _InputIterator>
+	void
+	_M_assign(_InputIterator __first, _InputIterator __last, false_type)
+	{
+	  clear();
+	  insert_after(cbefore_begin(), __first, __last);
+	}
+
+      // Called by assign(size_type, const _Tp&) if Tp is CopyAssignable
+      void
+      _M_assign_n(size_type __n, const _Tp& __val, true_type)
+      {
+	auto __prev = before_begin();
+	auto __curr = begin();
+	auto __end = end();
+	while (__curr != __end && __n > 0)
+	  {
+	    *__curr = __val;
+	    ++__prev;
+	    ++__curr;
+	    --__n;
+	  }
+	if (__n > 0)
+	  insert_after(__prev, __n, __val);
+	else if (__curr != __end)
+	  erase_after(__prev, __end);
+      }
+
+      // Called by assign(size_type, const _Tp&) if Tp is non-CopyAssignable
+      void
+      _M_assign_n(size_type __n, const _Tp& __val, false_type)
+      {
+	clear();
+	insert_after(cbefore_begin(), __n, __val);
+      }
+    };
+
+#if __cpp_deduction_guides >= 201606
+  template<typename _InputIterator, typename _ValT
+	     = typename iterator_traits<_InputIterator>::value_type,
+	   typename _Allocator = allocator<_ValT>,
+	   typename = _RequireInputIter<_InputIterator>,
+	   typename = _RequireAllocator<_Allocator>>
+    forward_list(_InputIterator, _InputIterator, _Allocator = _Allocator())
+      -> forward_list<_ValT, _Allocator>;
+#endif
+
+  /**
+   *  @brief  Forward list equality comparison.
+   *  @param  __lx  A %forward_list
+   *  @param  __ly  A %forward_list of the same type as @a __lx.
+   *  @return  True iff the elements of the forward lists are equal.
+   *
+   *  This is an equivalence relation.  It is linear in the number of
+   *  elements of the forward lists.  Deques are considered equivalent
+   *  if corresponding elements compare equal.
+   */
+  template<typename _Tp, typename _Alloc>
+    [[__nodiscard__]]
+    bool
+    operator==(const forward_list<_Tp, _Alloc>& __lx,
+	       const forward_list<_Tp, _Alloc>& __ly);
+
+#if __cpp_lib_three_way_comparison
+  /**
+   *  @brief  Forward list ordering relation.
+   *  @param  __x  A `forward_list`.
+   *  @param  __y  A `forward_list` of the same type as `__x`.
+   *  @return  A value indicating whether `__x` is less than, equal to,
+   *           greater than, or incomparable with `__y`.
+   *
+   *  See `std::lexicographical_compare_three_way()` for how the determination
+   *  is made. This operator is used to synthesize relational operators like
+   *  `<` and `>=` etc.
+  */
+  template<typename _Tp, typename _Alloc>
+    [[nodiscard]]
+    inline __detail::__synth3way_t<_Tp>
+    operator<=>(const forward_list<_Tp, _Alloc>& __x,
+		const forward_list<_Tp, _Alloc>& __y)
+    {
+      return std::lexicographical_compare_three_way(__x.begin(), __x.end(),
+						    __y.begin(), __y.end(),
+						    __detail::__synth3way);
+    }
+#else
+  /**
+   *  @brief  Forward list ordering relation.
+   *  @param  __lx  A %forward_list.
+   *  @param  __ly  A %forward_list of the same type as @a __lx.
+   *  @return  True iff @a __lx is lexicographically less than @a __ly.
+   *
+   *  This is a total ordering relation.  It is linear in the number of
+   *  elements of the forward lists.  The elements must be comparable
+   *  with @c <.
+   *
+   *  See std::lexicographical_compare() for how the determination is made.
+   */
+  template<typename _Tp, typename _Alloc>
+    [[__nodiscard__]]
+    inline bool
+    operator<(const forward_list<_Tp, _Alloc>& __lx,
+	      const forward_list<_Tp, _Alloc>& __ly)
+    { return std::lexicographical_compare(__lx.cbegin(), __lx.cend(),
+					  __ly.cbegin(), __ly.cend()); }
+
+  /// Based on operator==
+  template<typename _Tp, typename _Alloc>
+    [[__nodiscard__]]
+    inline bool
+    operator!=(const forward_list<_Tp, _Alloc>& __lx,
+	       const forward_list<_Tp, _Alloc>& __ly)
+    { return !(__lx == __ly); }
+
+  /// Based on operator<
+  template<typename _Tp, typename _Alloc>
+    [[__nodiscard__]]
+    inline bool
+    operator>(const forward_list<_Tp, _Alloc>& __lx,
+	      const forward_list<_Tp, _Alloc>& __ly)
+    { return (__ly < __lx); }
+
+  /// Based on operator<
+  template<typename _Tp, typename _Alloc>
+    [[__nodiscard__]]
+    inline bool
+    operator>=(const forward_list<_Tp, _Alloc>& __lx,
+	       const forward_list<_Tp, _Alloc>& __ly)
+    { return !(__lx < __ly); }
+
+  /// Based on operator<
+  template<typename _Tp, typename _Alloc>
+    [[__nodiscard__]]
+    inline bool
+    operator<=(const forward_list<_Tp, _Alloc>& __lx,
+	       const forward_list<_Tp, _Alloc>& __ly)
+    { return !(__ly < __lx); }
+#endif // three-way comparison
+
+  /// See std::forward_list::swap().
+  template<typename _Tp, typename _Alloc>
+    inline void
+    swap(forward_list<_Tp, _Alloc>& __lx,
+	 forward_list<_Tp, _Alloc>& __ly)
+    noexcept(noexcept(__lx.swap(__ly)))
+    { __lx.swap(__ly); }
+
+_GLIBCXX_END_NAMESPACE_CONTAINER
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif // _FORWARD_LIST_H
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@forward_list.tcc b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@forward_list.tcc
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@@ -0,0 +1,517 @@
+// <forward_list.tcc> -*- C++ -*-
+
+// Copyright (C) 2008-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/forward_list.tcc
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{forward_list}
+ */
+
+#ifndef _FORWARD_LIST_TCC
+#define _FORWARD_LIST_TCC 1
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+_GLIBCXX_BEGIN_NAMESPACE_CONTAINER
+
+  template<typename _Tp, typename _Alloc>
+    _Fwd_list_base<_Tp, _Alloc>::
+    _Fwd_list_base(_Fwd_list_base&& __lst, _Node_alloc_type&& __a)
+    : _M_impl(std::move(__a))
+    {
+      if (__lst._M_get_Node_allocator() == _M_get_Node_allocator())
+	this->_M_impl._M_head = std::move(__lst._M_impl._M_head);
+    }
+
+  template<typename _Tp, typename _Alloc>
+    template<typename... _Args>
+      _Fwd_list_node_base*
+      _Fwd_list_base<_Tp, _Alloc>::
+      _M_insert_after(const_iterator __pos, _Args&&... __args)
+      {
+	_Fwd_list_node_base* __to
+	  = const_cast<_Fwd_list_node_base*>(__pos._M_node);
+	_Node* __thing = _M_create_node(std::forward<_Args>(__args)...);
+	__thing->_M_next = __to->_M_next;
+	__to->_M_next = __thing;
+	return __to->_M_next;
+      }
+
+  template<typename _Tp, typename _Alloc>
+    _Fwd_list_node_base*
+    _Fwd_list_base<_Tp, _Alloc>::
+    _M_erase_after(_Fwd_list_node_base* __pos)
+    {
+      _Node* __curr = static_cast<_Node*>(__pos->_M_next);
+      __pos->_M_next = __curr->_M_next;
+      _Node_alloc_traits::destroy(_M_get_Node_allocator(),
+				  __curr->_M_valptr());
+      __curr->~_Node();
+      _M_put_node(__curr);
+      return __pos->_M_next;
+    }
+
+  template<typename _Tp, typename _Alloc>
+    _Fwd_list_node_base*
+    _Fwd_list_base<_Tp, _Alloc>::
+    _M_erase_after(_Fwd_list_node_base* __pos,
+		   _Fwd_list_node_base* __last)
+    {
+      _Node* __curr = static_cast<_Node*>(__pos->_M_next);
+      while (__curr != __last)
+	{
+	  _Node* __temp = __curr;
+	  __curr = static_cast<_Node*>(__curr->_M_next);
+	  _Node_alloc_traits::destroy(_M_get_Node_allocator(),
+				      __temp->_M_valptr());
+	  __temp->~_Node();
+	  _M_put_node(__temp);
+	}
+      __pos->_M_next = __last;
+      return __last;
+    }
+
+  // Called by the range constructor to implement [23.3.4.2]/9
+  template<typename _Tp, typename _Alloc>
+    template<typename _InputIterator>
+      void
+      forward_list<_Tp, _Alloc>::
+      _M_range_initialize(_InputIterator __first, _InputIterator __last)
+      {
+	_Node_base* __to = &this->_M_impl._M_head;
+	for (; __first != __last; ++__first)
+	  {
+	    __to->_M_next = this->_M_create_node(*__first);
+	    __to = __to->_M_next;
+	  }
+      }
+
+  // Called by forward_list(n,v,a).
+  template<typename _Tp, typename _Alloc>
+    void
+    forward_list<_Tp, _Alloc>::
+    _M_fill_initialize(size_type __n, const value_type& __value)
+    {
+      _Node_base* __to = &this->_M_impl._M_head;
+      for (; __n; --__n)
+	{
+	  __to->_M_next = this->_M_create_node(__value);
+	  __to = __to->_M_next;
+	}
+    }
+
+  template<typename _Tp, typename _Alloc>
+    void
+    forward_list<_Tp, _Alloc>::
+    _M_default_initialize(size_type __n)
+    {
+      _Node_base* __to = &this->_M_impl._M_head;
+      for (; __n; --__n)
+	{
+	  __to->_M_next = this->_M_create_node();
+	  __to = __to->_M_next;
+	}
+    }
+
+  template<typename _Tp, typename _Alloc>
+    forward_list<_Tp, _Alloc>&
+    forward_list<_Tp, _Alloc>::
+    operator=(const forward_list& __list)
+    {
+      if (std::__addressof(__list) != this)
+	{
+	  if (_Node_alloc_traits::_S_propagate_on_copy_assign())
+	    {
+	      auto& __this_alloc = this->_M_get_Node_allocator();
+	      auto& __that_alloc = __list._M_get_Node_allocator();
+	      if (!_Node_alloc_traits::_S_always_equal()
+		  && __this_alloc != __that_alloc)
+		{
+		  // replacement allocator cannot free existing storage
+		  clear();
+		}
+	      std::__alloc_on_copy(__this_alloc, __that_alloc);
+	    }
+	  assign(__list.cbegin(), __list.cend());
+	}
+      return *this;
+    }
+
+  template<typename _Tp, typename _Alloc>
+    void
+    forward_list<_Tp, _Alloc>::
+    _M_default_insert_after(const_iterator __pos, size_type __n)
+    {
+      const_iterator __saved_pos = __pos;
+      __try
+	{
+	  for (; __n; --__n)
+	    __pos = emplace_after(__pos);
+	}
+      __catch(...)
+	{
+	  erase_after(__saved_pos, ++__pos);
+	  __throw_exception_again;
+	}
+    }
+
+  template<typename _Tp, typename _Alloc>
+    void
+    forward_list<_Tp, _Alloc>::
+    resize(size_type __sz)
+    {
+      iterator __k = before_begin();
+
+      size_type __len = 0;
+      while (__k._M_next() != end() && __len < __sz)
+	{
+	  ++__k;
+	  ++__len;
+	}
+      if (__len == __sz)
+	erase_after(__k, end());
+      else
+	_M_default_insert_after(__k, __sz - __len);
+    }
+
+  template<typename _Tp, typename _Alloc>
+    void
+    forward_list<_Tp, _Alloc>::
+    resize(size_type __sz, const value_type& __val)
+    {
+      iterator __k = before_begin();
+
+      size_type __len = 0;
+      while (__k._M_next() != end() && __len < __sz)
+	{
+	  ++__k;
+	  ++__len;
+	}
+      if (__len == __sz)
+	erase_after(__k, end());
+      else
+	insert_after(__k, __sz - __len, __val);
+    }
+
+  template<typename _Tp, typename _Alloc>
+    typename forward_list<_Tp, _Alloc>::iterator
+    forward_list<_Tp, _Alloc>::
+    _M_splice_after(const_iterator __pos,
+		    const_iterator __before, const_iterator __last)
+    {
+      _Node_base* __tmp = const_cast<_Node_base*>(__pos._M_node);
+      _Node_base* __b = const_cast<_Node_base*>(__before._M_node);
+      _Node_base* __end = __b;
+
+      while (__end && __end->_M_next != __last._M_node)
+	__end = __end->_M_next;
+
+      if (__b != __end)
+	return iterator(__tmp->_M_transfer_after(__b, __end));
+      else
+	return iterator(__tmp);
+    }
+
+  template<typename _Tp, typename _Alloc>
+    void
+    forward_list<_Tp, _Alloc>::
+    splice_after(const_iterator __pos, forward_list&&,
+		 const_iterator __i) noexcept
+    {
+      const_iterator __j = __i;
+      ++__j;
+
+      if (__pos == __i || __pos == __j)
+	return;
+
+      _Node_base* __tmp = const_cast<_Node_base*>(__pos._M_node);
+      __tmp->_M_transfer_after(const_cast<_Node_base*>(__i._M_node),
+			       const_cast<_Node_base*>(__j._M_node));
+    }
+
+  template<typename _Tp, typename _Alloc>
+    typename forward_list<_Tp, _Alloc>::iterator
+    forward_list<_Tp, _Alloc>::
+    insert_after(const_iterator __pos, size_type __n, const _Tp& __val)
+    {
+      if (__n)
+	{
+	  forward_list __tmp(__n, __val, get_allocator());
+	  return _M_splice_after(__pos, __tmp.before_begin(), __tmp.end());
+	}
+      else
+	return iterator(const_cast<_Node_base*>(__pos._M_node));
+    }
+
+  template<typename _Tp, typename _Alloc>
+    template<typename _InputIterator, typename>
+      typename forward_list<_Tp, _Alloc>::iterator
+      forward_list<_Tp, _Alloc>::
+      insert_after(const_iterator __pos,
+		   _InputIterator __first, _InputIterator __last)
+      {
+	forward_list __tmp(__first, __last, get_allocator());
+	if (!__tmp.empty())
+	  return _M_splice_after(__pos, __tmp.before_begin(), __tmp.end());
+	else
+	  return iterator(const_cast<_Node_base*>(__pos._M_node));
+      }
+
+#if __cplusplus > 201703L
+# define _GLIBCXX20_ONLY(__expr) __expr
+#else
+# define _GLIBCXX20_ONLY(__expr)
+#endif
+
+  template<typename _Tp, typename _Alloc>
+    auto
+    forward_list<_Tp, _Alloc>::
+    remove(const _Tp& __val) -> __remove_return_type
+    {
+      size_type __removed __attribute__((__unused__)) = 0;
+      forward_list __to_destroy(get_allocator());
+
+      auto __prev_it = cbefore_begin();
+      while (_Node* __tmp = static_cast<_Node*>(__prev_it._M_node->_M_next))
+	if (*__tmp->_M_valptr() == __val)
+	  {
+	    __to_destroy.splice_after(__to_destroy.cbefore_begin(),
+				      *this, __prev_it);
+	    _GLIBCXX20_ONLY( __removed++ );
+	  }
+	else
+	  ++__prev_it;
+
+      return _GLIBCXX20_ONLY( __removed );
+    }
+
+  template<typename _Tp, typename _Alloc>
+    template<typename _Pred>
+      auto
+      forward_list<_Tp, _Alloc>::
+      remove_if(_Pred __pred) -> __remove_return_type
+      {
+	size_type __removed __attribute__((__unused__)) = 0;
+	forward_list __to_destroy(get_allocator());
+
+	auto __prev_it = cbefore_begin();
+	while (_Node* __tmp = static_cast<_Node*>(__prev_it._M_node->_M_next))
+	  if (__pred(*__tmp->_M_valptr()))
+	    {
+	      __to_destroy.splice_after(__to_destroy.cbefore_begin(),
+					*this, __prev_it);
+	      _GLIBCXX20_ONLY( __removed++ );
+	    }
+	  else
+	    ++__prev_it;
+
+	return _GLIBCXX20_ONLY( __removed );
+      }
+
+  template<typename _Tp, typename _Alloc>
+    template<typename _BinPred>
+      auto
+      forward_list<_Tp, _Alloc>::
+      unique(_BinPred __binary_pred) -> __remove_return_type
+      {
+	iterator __first = begin();
+	iterator __last = end();
+	if (__first == __last)
+	  return _GLIBCXX20_ONLY(0);
+
+	forward_list __to_destroy(get_allocator());
+	size_type __removed __attribute__((__unused__)) = 0;
+	iterator __next = __first;
+	while (++__next != __last)
+	{
+	  if (__binary_pred(*__first, *__next))
+	    {
+	      __to_destroy.splice_after(__to_destroy.cbefore_begin(),
+					*this, __first);
+	      _GLIBCXX20_ONLY( __removed++ );
+	    }
+	  else
+	    __first = __next;
+	  __next = __first;
+	}
+
+	return _GLIBCXX20_ONLY( __removed );
+      }
+
+#undef _GLIBCXX20_ONLY
+
+  template<typename _Tp, typename _Alloc>
+    template<typename _Comp>
+      void
+      forward_list<_Tp, _Alloc>::
+      merge(forward_list&& __list, _Comp __comp)
+      {
+	// _GLIBCXX_RESOLVE_LIB_DEFECTS
+	// 3088. forward_list::merge behavior unclear when passed *this
+	if (std::__addressof(__list) == this)
+	  return;
+
+	_Node_base* __node = &this->_M_impl._M_head;
+	while (__node->_M_next && __list._M_impl._M_head._M_next)
+	  {
+	    if (__comp(*static_cast<_Node*>
+		       (__list._M_impl._M_head._M_next)->_M_valptr(),
+		       *static_cast<_Node*>
+		       (__node->_M_next)->_M_valptr()))
+	      __node->_M_transfer_after(&__list._M_impl._M_head,
+					__list._M_impl._M_head._M_next);
+	    __node = __node->_M_next;
+	  }
+
+	if (__list._M_impl._M_head._M_next)
+	  *__node = std::move(__list._M_impl._M_head);
+      }
+
+  template<typename _Tp, typename _Alloc>
+    bool
+    operator==(const forward_list<_Tp, _Alloc>& __lx,
+	       const forward_list<_Tp, _Alloc>& __ly)
+    {
+      //  We don't have size() so we need to walk through both lists
+      //  making sure both iterators are valid.
+      auto __ix = __lx.cbegin();
+      auto __iy = __ly.cbegin();
+      while (__ix != __lx.cend() && __iy != __ly.cend())
+	{
+	  if (!(*__ix == *__iy))
+	    return false;
+	  ++__ix;
+	  ++__iy;
+	}
+      if (__ix == __lx.cend() && __iy == __ly.cend())
+	return true;
+      else
+	return false;
+    }
+
+  template<typename _Tp, class _Alloc>
+    template<typename _Comp>
+      void
+      forward_list<_Tp, _Alloc>::
+      sort(_Comp __comp)
+      {
+	// If `next' is nullptr, return immediately.
+	_Node* __list = static_cast<_Node*>(this->_M_impl._M_head._M_next);
+	if (!__list)
+	  return;
+
+	unsigned long __insize = 1;
+
+	while (1)
+	  {
+	    _Node* __p = __list;
+	    __list = nullptr;
+	    _Node* __tail = nullptr;
+
+	    // Count number of merges we do in this pass.
+	    unsigned long __nmerges = 0;
+
+	    while (__p)
+	      {
+		++__nmerges;
+		// There exists a merge to be done.
+		// Step `insize' places along from p.
+		_Node* __q = __p;
+		unsigned long __psize = 0;
+		for (unsigned long __i = 0; __i < __insize; ++__i)
+		  {
+		    ++__psize;
+		    __q = static_cast<_Node*>(__q->_M_next);
+		    if (!__q)
+		      break;
+		  }
+
+		// If q hasn't fallen off end, we have two lists to merge.
+		unsigned long __qsize = __insize;
+
+		// Now we have two lists; merge them.
+		while (__psize > 0 || (__qsize > 0 && __q))
+		  {
+		    // Decide whether next node of merge comes from p or q.
+		    _Node* __e;
+		    if (__psize == 0)
+		      {
+			// p is empty; e must come from q.
+			__e = __q;
+			__q = static_cast<_Node*>(__q->_M_next);
+			--__qsize;
+		      }
+		    else if (__qsize == 0 || !__q)
+		      {
+			// q is empty; e must come from p.
+			__e = __p;
+			__p = static_cast<_Node*>(__p->_M_next);
+			--__psize;
+		      }
+		    else if (!__comp(*__q->_M_valptr(), *__p->_M_valptr()))
+		      {
+			// First node of q is not lower; e must come from p.
+			__e = __p;
+			__p = static_cast<_Node*>(__p->_M_next);
+			--__psize;
+		      }
+		    else
+		      {
+			// First node of q is lower; e must come from q.
+			__e = __q;
+			__q = static_cast<_Node*>(__q->_M_next);
+			--__qsize;
+		      }
+
+		    // Add the next node to the merged list.
+		    if (__tail)
+		      __tail->_M_next = __e;
+		    else
+		      __list = __e;
+		    __tail = __e;
+		  }
+
+		// Now p has stepped `insize' places along, and q has too.
+		__p = __q;
+	      }
+	    __tail->_M_next = nullptr;
+
+	    // If we have done only one merge, we're finished.
+	    // Allow for nmerges == 0, the empty list case.
+	    if (__nmerges <= 1)
+	      {
+		this->_M_impl._M_head._M_next = __list;
+		return;
+	      }
+
+	    // Otherwise repeat, merging lists twice the size.
+	    __insize *= 2;
+	  }
+      }
+
+_GLIBCXX_END_NAMESPACE_CONTAINER
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif /* _FORWARD_LIST_TCC */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@forward_list.tcc.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@forward_list.tcc.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@fstream.tcc b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@fstream.tcc
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@fstream.tcc
@@ -0,0 +1,1102 @@
+// File based streams -*- C++ -*-
+
+// Copyright (C) 1997-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/fstream.tcc
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{fstream}
+ */
+
+//
+// ISO C++ 14882: 27.8  File-based streams
+//
+
+#ifndef _FSTREAM_TCC
+#define _FSTREAM_TCC 1
+
+#pragma GCC system_header
+
+#include <bits/cxxabi_forced.h>
+#include <bits/move.h>   // for swap
+#include <cerrno>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  template<typename _CharT, typename _Traits>
+    void
+    basic_filebuf<_CharT, _Traits>::
+    _M_allocate_internal_buffer()
+    {
+      // Allocate internal buffer only if one doesn't already exist
+      // (either allocated or provided by the user via setbuf).
+      if (!_M_buf_allocated && !_M_buf)
+	{
+	  _M_buf = new char_type[_M_buf_size];
+	  _M_buf_allocated = true;
+	}
+    }
+
+  template<typename _CharT, typename _Traits>
+    void
+    basic_filebuf<_CharT, _Traits>::
+    _M_destroy_internal_buffer() throw()
+    {
+      if (_M_buf_allocated)
+	{
+	  delete [] _M_buf;
+	  _M_buf = 0;
+	  _M_buf_allocated = false;
+	}
+      delete [] _M_ext_buf;
+      _M_ext_buf = 0;
+      _M_ext_buf_size = 0;
+      _M_ext_next = 0;
+      _M_ext_end = 0;
+    }
+
+  template<typename _CharT, typename _Traits>
+    basic_filebuf<_CharT, _Traits>::
+    basic_filebuf() : __streambuf_type(), _M_lock(), _M_file(&_M_lock),
+    _M_mode(ios_base::openmode(0)), _M_state_beg(), _M_state_cur(),
+    _M_state_last(), _M_buf(0), _M_buf_size(_GLIBCXX_BUFSIZ),
+    _M_buf_allocated(false), _M_reading(false), _M_writing(false), _M_pback(), 
+    _M_pback_cur_save(0), _M_pback_end_save(0), _M_pback_init(false),
+    _M_codecvt(0), _M_ext_buf(0), _M_ext_buf_size(0), _M_ext_next(0),
+    _M_ext_end(0)
+    {
+      if (has_facet<__codecvt_type>(this->_M_buf_locale))
+	_M_codecvt = &use_facet<__codecvt_type>(this->_M_buf_locale);
+    }
+
+#if __cplusplus >= 201103L
+  template<typename _CharT, typename _Traits>
+    basic_filebuf<_CharT, _Traits>::
+    basic_filebuf(basic_filebuf&& __rhs)
+    : __streambuf_type(__rhs),
+    _M_lock(), _M_file(std::move(__rhs._M_file), &_M_lock),
+    _M_mode(std::__exchange(__rhs._M_mode, ios_base::openmode(0))),
+    _M_state_beg(std::move(__rhs._M_state_beg)),
+    _M_state_cur(std::move(__rhs._M_state_cur)),
+    _M_state_last(std::move(__rhs._M_state_last)),
+    _M_buf(std::__exchange(__rhs._M_buf, nullptr)),
+    _M_buf_size(std::__exchange(__rhs._M_buf_size, 1)),
+    _M_buf_allocated(std::__exchange(__rhs._M_buf_allocated, false)),
+    _M_reading(std::__exchange(__rhs._M_reading, false)),
+    _M_writing(std::__exchange(__rhs._M_writing, false)),
+    _M_pback(__rhs._M_pback),
+    _M_pback_cur_save(std::__exchange(__rhs._M_pback_cur_save, nullptr)),
+    _M_pback_end_save(std::__exchange(__rhs._M_pback_end_save, nullptr)),
+    _M_pback_init(std::__exchange(__rhs._M_pback_init, false)),
+    _M_codecvt(__rhs._M_codecvt),
+    _M_ext_buf(std::__exchange(__rhs._M_ext_buf, nullptr)),
+    _M_ext_buf_size(std::__exchange(__rhs._M_ext_buf_size, 0)),
+    _M_ext_next(std::__exchange(__rhs._M_ext_next, nullptr)),
+    _M_ext_end(std::__exchange(__rhs._M_ext_end, nullptr))
+    {
+      __rhs._M_set_buffer(-1);
+      __rhs._M_state_last = __rhs._M_state_cur = __rhs._M_state_beg;
+    }
+
+  template<typename _CharT, typename _Traits>
+    basic_filebuf<_CharT, _Traits>&
+    basic_filebuf<_CharT, _Traits>::
+    operator=(basic_filebuf&& __rhs)
+    {
+      this->close();
+      __streambuf_type::operator=(__rhs);
+      _M_file.swap(__rhs._M_file);
+      _M_mode = std::__exchange(__rhs._M_mode, ios_base::openmode(0));
+      _M_state_beg = std::move(__rhs._M_state_beg);
+      _M_state_cur = std::move(__rhs._M_state_cur);
+      _M_state_last = std::move(__rhs._M_state_last);
+      _M_buf = std::__exchange(__rhs._M_buf, nullptr);
+      _M_buf_size = std::__exchange(__rhs._M_buf_size, 1);
+      _M_buf_allocated = std::__exchange(__rhs._M_buf_allocated, false);
+      _M_ext_buf = std::__exchange(__rhs._M_ext_buf, nullptr);
+      _M_ext_buf_size = std::__exchange(__rhs._M_ext_buf_size, 0);
+      _M_ext_next = std::__exchange(__rhs._M_ext_next, nullptr);
+      _M_ext_end = std::__exchange(__rhs._M_ext_end, nullptr);
+      _M_reading = std::__exchange(__rhs._M_reading, false);
+      _M_writing = std::__exchange(__rhs._M_writing, false);
+      _M_pback_cur_save = std::__exchange(__rhs._M_pback_cur_save, nullptr);
+      _M_pback_end_save = std::__exchange(__rhs._M_pback_end_save, nullptr);
+      _M_pback_init = std::__exchange(__rhs._M_pback_init, false);
+      __rhs._M_set_buffer(-1);
+      __rhs._M_state_last = __rhs._M_state_cur = __rhs._M_state_beg;
+      return *this;
+    }
+
+  template<typename _CharT, typename _Traits>
+    void
+    basic_filebuf<_CharT, _Traits>::
+    swap(basic_filebuf& __rhs)
+    {
+      __streambuf_type::swap(__rhs);
+      _M_file.swap(__rhs._M_file);
+      std::swap(_M_mode, __rhs._M_mode);
+      std::swap(_M_state_beg, __rhs._M_state_beg);
+      std::swap(_M_state_cur, __rhs._M_state_cur);
+      std::swap(_M_state_last, __rhs._M_state_last);
+      std::swap(_M_buf, __rhs._M_buf);
+      std::swap(_M_buf_size, __rhs._M_buf_size);
+      std::swap(_M_buf_allocated, __rhs._M_buf_allocated);
+      std::swap(_M_ext_buf, __rhs._M_ext_buf);
+      std::swap(_M_ext_buf_size, __rhs._M_ext_buf_size);
+      std::swap(_M_ext_next, __rhs._M_ext_next);
+      std::swap(_M_ext_end, __rhs._M_ext_end);
+      std::swap(_M_reading, __rhs._M_reading);
+      std::swap(_M_writing, __rhs._M_writing);
+      std::swap(_M_pback_cur_save, __rhs._M_pback_cur_save);
+      std::swap(_M_pback_end_save, __rhs._M_pback_end_save);
+      std::swap(_M_pback_init, __rhs._M_pback_init);
+    }
+#endif
+
+  template<typename _CharT, typename _Traits>
+    typename basic_filebuf<_CharT, _Traits>::__filebuf_type*
+    basic_filebuf<_CharT, _Traits>::
+    open(const char* __s, ios_base::openmode __mode)
+    {
+      __filebuf_type *__ret = 0;
+      if (!this->is_open())
+	{
+	  _M_file.open(__s, __mode);
+	  if (this->is_open())
+	    {
+	      _M_allocate_internal_buffer();
+	      _M_mode = __mode;
+
+	      // Setup initial buffer to 'uncommitted' mode.
+	      _M_reading = false;
+	      _M_writing = false;
+	      _M_set_buffer(-1);
+
+	      // Reset to initial state.
+	      _M_state_last = _M_state_cur = _M_state_beg;
+
+	      // 27.8.1.3,4
+	      if ((__mode & ios_base::ate)
+		  && this->seekoff(0, ios_base::end, __mode)
+		  == pos_type(off_type(-1)))
+		this->close();
+	      else
+		__ret = this;
+	    }
+	}
+      return __ret;
+    }
+
+#if _GLIBCXX_HAVE__WFOPEN && _GLIBCXX_USE_WCHAR_T
+  template<typename _CharT, typename _Traits>
+    basic_filebuf<_CharT, _Traits>*
+    basic_filebuf<_CharT, _Traits>::
+    open(const wchar_t* __s, ios_base::openmode __mode)
+    {
+      __filebuf_type *__ret = 0;
+      if (!this->is_open())
+	{
+	  _M_file.open(__s, __mode);
+	  if (this->is_open())
+	    {
+	      _M_allocate_internal_buffer();
+	      _M_mode = __mode;
+
+	      // Setup initial buffer to 'uncommitted' mode.
+	      _M_reading = false;
+	      _M_writing = false;
+	      _M_set_buffer(-1);
+
+	      // Reset to initial state.
+	      _M_state_last = _M_state_cur = _M_state_beg;
+
+	      // 27.8.1.3,4
+	      if ((__mode & ios_base::ate)
+		  && this->seekoff(0, ios_base::end, __mode)
+		  == pos_type(off_type(-1)))
+		this->close();
+	      else
+		__ret = this;
+	    }
+	}
+      return __ret;
+    }
+#endif // HAVE__WFOPEN && USE_WCHAR_T
+
+  template<typename _CharT, typename _Traits>
+    typename basic_filebuf<_CharT, _Traits>::__filebuf_type*
+    basic_filebuf<_CharT, _Traits>::
+    close()
+    {
+      if (!this->is_open())
+	return 0;
+
+      bool __testfail = false;
+      {
+	// NB: Do this here so that re-opened filebufs will be cool...
+	struct __close_sentry
+	{
+	  basic_filebuf *__fb;
+	  __close_sentry (basic_filebuf *__fbi): __fb(__fbi) { }
+	  ~__close_sentry ()
+	  {
+	    __fb->_M_mode = ios_base::openmode(0);
+	    __fb->_M_pback_init = false;
+	    __fb->_M_destroy_internal_buffer();
+	    __fb->_M_reading = false;
+	    __fb->_M_writing = false;
+	    __fb->_M_set_buffer(-1);
+	    __fb->_M_state_last = __fb->_M_state_cur = __fb->_M_state_beg;
+	  }
+	} __cs (this);
+
+	__try
+	  {
+	    if (!_M_terminate_output())
+	      __testfail = true;
+	  }
+	__catch(...)
+	  {
+	    _M_file.close();
+	    __throw_exception_again;
+	  }
+      }
+
+      if (!_M_file.close())
+	__testfail = true;
+
+      if (__testfail)
+	return 0;
+      else
+	return this;
+    }
+
+  template<typename _CharT, typename _Traits>
+    streamsize
+    basic_filebuf<_CharT, _Traits>::
+    showmanyc()
+    {
+      streamsize __ret = -1;
+      const bool __testin = _M_mode & ios_base::in;
+      if (__testin && this->is_open())
+	{
+	  // For a stateful encoding (-1) the pending sequence might be just
+	  // shift and unshift prefixes with no actual character.
+	  __ret = this->egptr() - this->gptr();
+
+#if _GLIBCXX_HAVE_DOS_BASED_FILESYSTEM
+	  // About this workaround, see libstdc++/20806.
+	  const bool __testbinary = _M_mode & ios_base::binary;
+	  if (__check_facet(_M_codecvt).encoding() >= 0
+	      && __testbinary)
+#else
+	  if (__check_facet(_M_codecvt).encoding() >= 0)
+#endif
+	    __ret += _M_file.showmanyc() / _M_codecvt->max_length();
+	}
+      return __ret;
+    }
+
+  template<typename _CharT, typename _Traits>
+    typename basic_filebuf<_CharT, _Traits>::int_type
+    basic_filebuf<_CharT, _Traits>::
+    underflow()
+    {
+      int_type __ret = traits_type::eof();
+      const bool __testin = _M_mode & ios_base::in;
+      if (__testin)
+	{
+	  if (_M_writing)
+	    {
+	      if (overflow() == traits_type::eof())
+		return __ret;
+	      _M_set_buffer(-1);
+	      _M_writing = false;
+	    }
+	  // Check for pback madness, and if so switch back to the
+	  // normal buffers and jet outta here before expensive
+	  // fileops happen...
+	  _M_destroy_pback();
+
+	  if (this->gptr() < this->egptr())
+	    return traits_type::to_int_type(*this->gptr());
+
+	  // Get and convert input sequence.
+	  const size_t __buflen = _M_buf_size > 1 ? _M_buf_size - 1 : 1;
+
+	  // Will be set to true if ::read() returns 0 indicating EOF.
+	  bool __got_eof = false;
+	  // Number of internal characters produced.
+	  streamsize __ilen = 0;
+	  codecvt_base::result __r = codecvt_base::ok;
+	  if (__check_facet(_M_codecvt).always_noconv())
+	    {
+	      __ilen = _M_file.xsgetn(reinterpret_cast<char*>(this->eback()),
+				      __buflen);
+	      if (__ilen == 0)
+		__got_eof = true;
+	    }
+	  else
+	    {
+              // Worst-case number of external bytes.
+	      // XXX Not done encoding() == -1.
+	      const int __enc = _M_codecvt->encoding();
+	      streamsize __blen; // Minimum buffer size.
+	      streamsize __rlen; // Number of chars to read.
+	      if (__enc > 0)
+		__blen = __rlen = __buflen * __enc;
+	      else
+		{
+		  __blen = __buflen + _M_codecvt->max_length() - 1;
+		  __rlen = __buflen;
+		}
+	      const streamsize __remainder = _M_ext_end - _M_ext_next;
+	      __rlen = __rlen > __remainder ? __rlen - __remainder : 0;
+
+	      // An imbue in 'read' mode implies first converting the external
+	      // chars already present.
+	      if (_M_reading && this->egptr() == this->eback() && __remainder)
+		__rlen = 0;
+
+	      // Allocate buffer if necessary and move unconverted
+	      // bytes to front.
+	      if (_M_ext_buf_size < __blen)
+		{
+		  char* __buf = new char[__blen];
+		  if (__remainder)
+		    __builtin_memcpy(__buf, _M_ext_next, __remainder);
+
+		  delete [] _M_ext_buf;
+		  _M_ext_buf = __buf;
+		  _M_ext_buf_size = __blen;
+		}
+	      else if (__remainder)
+		__builtin_memmove(_M_ext_buf, _M_ext_next, __remainder);
+
+	      _M_ext_next = _M_ext_buf;
+	      _M_ext_end = _M_ext_buf + __remainder;
+	      _M_state_last = _M_state_cur;
+
+	      do
+		{
+		  if (__rlen > 0)
+		    {
+		      // Sanity check!
+		      // This may fail if the return value of
+		      // codecvt::max_length() is bogus.
+		      if (_M_ext_end - _M_ext_buf + __rlen > _M_ext_buf_size)
+			{
+			  __throw_ios_failure(__N("basic_filebuf::underflow "
+					      "codecvt::max_length() "
+					      "is not valid"));
+			}
+		      streamsize __elen = _M_file.xsgetn(_M_ext_end, __rlen);
+		      if (__elen == 0)
+			__got_eof = true;
+		      else if (__elen == -1)
+			break;
+		      _M_ext_end += __elen;
+		    }
+
+		  char_type* __iend = this->eback();
+		  if (_M_ext_next < _M_ext_end)
+		    __r = _M_codecvt->in(_M_state_cur, _M_ext_next,
+					 _M_ext_end, _M_ext_next,
+					 this->eback(),
+					 this->eback() + __buflen, __iend);
+		  if (__r == codecvt_base::noconv)
+		    {
+		      size_t __avail = _M_ext_end - _M_ext_buf;
+		      __ilen = std::min(__avail, __buflen);
+		      traits_type::copy(this->eback(),
+					reinterpret_cast<char_type*>
+					(_M_ext_buf), __ilen);
+		      _M_ext_next = _M_ext_buf + __ilen;
+		    }
+		  else
+		    __ilen = __iend - this->eback();
+
+		  // _M_codecvt->in may return error while __ilen > 0: this is
+		  // ok, and actually occurs in case of mixed encodings (e.g.,
+		  // XML files).
+		  if (__r == codecvt_base::error)
+		    break;
+
+		  __rlen = 1;
+		}
+	      while (__ilen == 0 && !__got_eof);
+	    }
+
+	  if (__ilen > 0)
+	    {
+	      _M_set_buffer(__ilen);
+	      _M_reading = true;
+	      __ret = traits_type::to_int_type(*this->gptr());
+	    }
+	  else if (__got_eof)
+	    {
+	      // If the actual end of file is reached, set 'uncommitted'
+	      // mode, thus allowing an immediate write without an
+	      // intervening seek.
+	      _M_set_buffer(-1);
+	      _M_reading = false;
+	      // However, reaching it while looping on partial means that
+	      // the file has got an incomplete character.
+	      if (__r == codecvt_base::partial)
+		__throw_ios_failure(__N("basic_filebuf::underflow "
+				    "incomplete character in file"));
+	    }
+	  else if (__r == codecvt_base::error)
+	    __throw_ios_failure(__N("basic_filebuf::underflow "
+				"invalid byte sequence in file"));
+	  else
+	    __throw_ios_failure(__N("basic_filebuf::underflow "
+				"error reading the file"), errno);
+	}
+      return __ret;
+    }
+
+  template<typename _CharT, typename _Traits>
+    typename basic_filebuf<_CharT, _Traits>::int_type
+    basic_filebuf<_CharT, _Traits>::
+    pbackfail(int_type __i)
+    {
+      int_type __ret = traits_type::eof();
+      const bool __testin = _M_mode & ios_base::in;
+      if (__testin)
+	{
+	  if (_M_writing)
+	    {
+	      if (overflow() == traits_type::eof())
+		return __ret;
+	      _M_set_buffer(-1);
+	      _M_writing = false;
+	    }
+	  // Remember whether the pback buffer is active, otherwise below
+	  // we may try to store in it a second char (libstdc++/9761).
+	  const bool __testpb = _M_pback_init;
+	  const bool __testeof = traits_type::eq_int_type(__i, __ret);
+	  int_type __tmp;
+	  if (this->eback() < this->gptr())
+	    {
+	      this->gbump(-1);
+	      __tmp = traits_type::to_int_type(*this->gptr());
+	    }
+	  else if (this->seekoff(-1, ios_base::cur) != pos_type(off_type(-1)))
+	    {
+	      __tmp = this->underflow();
+	      if (traits_type::eq_int_type(__tmp, __ret))
+		return __ret;
+	    }
+	  else
+	    {
+	      // At the beginning of the buffer, need to make a
+	      // putback position available.  But the seek may fail
+	      // (f.i., at the beginning of a file, see
+	      // libstdc++/9439) and in that case we return
+	      // traits_type::eof().
+	      return __ret;
+	    }
+
+	  // Try to put back __i into input sequence in one of three ways.
+	  // Order these tests done in is unspecified by the standard.
+	  if (!__testeof && traits_type::eq_int_type(__i, __tmp))
+	    __ret = __i;
+	  else if (__testeof)
+	    __ret = traits_type::not_eof(__i);
+	  else if (!__testpb)
+	    {
+	      _M_create_pback();
+	      _M_reading = true;
+	      *this->gptr() = traits_type::to_char_type(__i);
+	      __ret = __i;
+	    }
+	}
+      return __ret;
+    }
+
+  template<typename _CharT, typename _Traits>
+    typename basic_filebuf<_CharT, _Traits>::int_type
+    basic_filebuf<_CharT, _Traits>::
+    overflow(int_type __c)
+    {
+      int_type __ret = traits_type::eof();
+      const bool __testeof = traits_type::eq_int_type(__c, __ret);
+      const bool __testout = (_M_mode & ios_base::out
+			      || _M_mode & ios_base::app);
+      if (__testout)
+	{
+          if (_M_reading)
+            {
+              _M_destroy_pback();
+              const int __gptr_off = _M_get_ext_pos(_M_state_last);
+              if (_M_seek(__gptr_off, ios_base::cur, _M_state_last)
+                  == pos_type(off_type(-1)))
+                return __ret;
+            }
+	  if (this->pbase() < this->pptr())
+	    {
+	      // If appropriate, append the overflow char.
+	      if (!__testeof)
+		{
+		  *this->pptr() = traits_type::to_char_type(__c);
+		  this->pbump(1);
+		}
+
+	      // Convert pending sequence to external representation,
+	      // and output.
+	      if (_M_convert_to_external(this->pbase(),
+					 this->pptr() - this->pbase()))
+		{
+		  _M_set_buffer(0);
+		  __ret = traits_type::not_eof(__c);
+		}
+	    }
+	  else if (_M_buf_size > 1)
+	    {
+	      // Overflow in 'uncommitted' mode: set _M_writing, set
+	      // the buffer to the initial 'write' mode, and put __c
+	      // into the buffer.
+	      _M_set_buffer(0);
+	      _M_writing = true;
+	      if (!__testeof)
+		{
+		  *this->pptr() = traits_type::to_char_type(__c);
+		  this->pbump(1);
+		}
+	      __ret = traits_type::not_eof(__c);
+	    }
+	  else
+	    {
+	      // Unbuffered.
+	      char_type __conv = traits_type::to_char_type(__c);
+	      if (__testeof || _M_convert_to_external(&__conv, 1))
+		{
+		  _M_writing = true;
+		  __ret = traits_type::not_eof(__c);
+		}
+	    }
+	}
+      return __ret;
+    }
+
+  template<typename _CharT, typename _Traits>
+    bool
+    basic_filebuf<_CharT, _Traits>::
+    _M_convert_to_external(_CharT* __ibuf, streamsize __ilen)
+    {
+      // Sizes of external and pending output.
+      streamsize __elen;
+      streamsize __plen;
+      if (__check_facet(_M_codecvt).always_noconv())
+	{
+	  __elen = _M_file.xsputn(reinterpret_cast<char*>(__ibuf), __ilen);
+	  __plen = __ilen;
+	}
+      else
+	{
+	  // Worst-case number of external bytes needed.
+	  // XXX Not done encoding() == -1.
+	  streamsize __blen = __ilen * _M_codecvt->max_length();
+	  char* __buf = static_cast<char*>(__builtin_alloca(__blen));
+
+	  char* __bend;
+	  const char_type* __iend;
+	  codecvt_base::result __r;
+	  __r = _M_codecvt->out(_M_state_cur, __ibuf, __ibuf + __ilen,
+				__iend, __buf, __buf + __blen, __bend);
+
+	  if (__r == codecvt_base::ok || __r == codecvt_base::partial)
+	    __blen = __bend - __buf;
+	  else if (__r == codecvt_base::noconv)
+	    {
+	      // Same as the always_noconv case above.
+	      __buf = reinterpret_cast<char*>(__ibuf);
+	      __blen = __ilen;
+	    }
+	  else
+	    __throw_ios_failure(__N("basic_filebuf::_M_convert_to_external "
+				    "conversion error"));
+  
+	  __elen = _M_file.xsputn(__buf, __blen);
+	  __plen = __blen;
+
+	  // Try once more for partial conversions.
+	  if (__r == codecvt_base::partial && __elen == __plen)
+	    {
+	      const char_type* __iresume = __iend;
+	      streamsize __rlen = this->pptr() - __iend;
+	      __r = _M_codecvt->out(_M_state_cur, __iresume,
+				    __iresume + __rlen, __iend, __buf,
+				    __buf + __blen, __bend);
+	      if (__r != codecvt_base::error)
+		{
+		  __rlen = __bend - __buf;
+		  __elen = _M_file.xsputn(__buf, __rlen);
+		  __plen = __rlen;
+		}
+	      else
+		__throw_ios_failure(__N("basic_filebuf::_M_convert_to_external "
+					"conversion error"));
+	    }
+	}
+      return __elen == __plen;
+    }
+
+  template<typename _CharT, typename _Traits>
+    streamsize
+    basic_filebuf<_CharT, _Traits>::
+    xsgetn(_CharT* __s, streamsize __n)
+    {
+      // Clear out pback buffer before going on to the real deal...
+      streamsize __ret = 0;
+      if (_M_pback_init)
+	{
+	  if (__n > 0 && this->gptr() == this->eback())
+	    {
+	      *__s++ = *this->gptr(); // emulate non-underflowing sbumpc
+	      this->gbump(1);
+	      __ret = 1;
+	      --__n;
+	    }
+	  _M_destroy_pback();
+	}
+      else if (_M_writing)
+	{
+	  if (overflow() == traits_type::eof())
+	    return __ret;
+	  _M_set_buffer(-1);
+	  _M_writing = false;
+	}
+ 
+      // Optimization in the always_noconv() case, to be generalized in the
+      // future: when __n > __buflen we read directly instead of using the
+      // buffer repeatedly.
+      const bool __testin = _M_mode & ios_base::in;
+      const streamsize __buflen = _M_buf_size > 1 ? _M_buf_size - 1 : 1;
+ 
+      if (__n > __buflen && __check_facet(_M_codecvt).always_noconv()
+	  && __testin)
+	{
+	  // First, copy the chars already present in the buffer.
+	  const streamsize __avail = this->egptr() - this->gptr();
+	  if (__avail != 0)
+	    {
+	      traits_type::copy(__s, this->gptr(), __avail);
+	      __s += __avail;
+	      this->setg(this->eback(), this->gptr() + __avail, this->egptr());
+	      __ret += __avail;
+	      __n -= __avail;
+	    }
+ 
+	  // Need to loop in case of short reads (relatively common
+	  // with pipes).
+	  streamsize __len;
+	  for (;;)
+	    {
+	      __len = _M_file.xsgetn(reinterpret_cast<char*>(__s), __n);
+	      if (__len == -1)
+		__throw_ios_failure(__N("basic_filebuf::xsgetn "
+					"error reading the file"), errno);
+	      if (__len == 0)
+		break;
+ 
+	      __n -= __len;
+	      __ret += __len;
+	      if (__n == 0)
+		break;
+
+	      __s += __len;
+	    }
+
+	  if (__n == 0)
+	    {
+	      // Set _M_reading. Buffer is already in initial 'read' mode.
+	      _M_reading = true;
+	    }
+	  else if (__len == 0)
+	    {
+	      // If end of file is reached, set 'uncommitted'
+	      // mode, thus allowing an immediate write without
+	      // an intervening seek.
+	      _M_set_buffer(-1);
+	      _M_reading = false;
+	    }
+	}
+      else
+	__ret += __streambuf_type::xsgetn(__s, __n);
+ 
+      return __ret;
+    }
+
+  template<typename _CharT, typename _Traits>
+    streamsize
+    basic_filebuf<_CharT, _Traits>::
+    xsputn(const _CharT* __s, streamsize __n)
+    {
+      streamsize __ret = 0;
+      // Optimization in the always_noconv() case, to be generalized in the
+      // future: when __n is sufficiently large we write directly instead of
+      // using the buffer.
+      const bool __testout = (_M_mode & ios_base::out
+			      || _M_mode & ios_base::app);
+      if (__check_facet(_M_codecvt).always_noconv()
+	  && __testout && !_M_reading)
+	{
+	  // Measurement would reveal the best choice.
+	  const streamsize __chunk = 1ul << 10;
+	  streamsize __bufavail = this->epptr() - this->pptr();
+
+	  // Don't mistake 'uncommitted' mode buffered with unbuffered.
+	  if (!_M_writing && _M_buf_size > 1)
+	    __bufavail = _M_buf_size - 1;
+
+	  const streamsize __limit = std::min(__chunk, __bufavail);
+	  if (__n >= __limit)
+	    {
+	      const streamsize __buffill = this->pptr() - this->pbase();
+	      const char* __buf = reinterpret_cast<const char*>(this->pbase());
+	      __ret = _M_file.xsputn_2(__buf, __buffill,
+				       reinterpret_cast<const char*>(__s),
+				       __n);
+	      if (__ret == __buffill + __n)
+		{
+		  _M_set_buffer(0);
+		  _M_writing = true;
+		}
+	      if (__ret > __buffill)
+		__ret -= __buffill;
+	      else
+		__ret = 0;
+	    }
+	  else
+	    __ret = __streambuf_type::xsputn(__s, __n);
+	}
+       else
+	 __ret = __streambuf_type::xsputn(__s, __n);
+       return __ret;
+    }
+
+  template<typename _CharT, typename _Traits>
+    typename basic_filebuf<_CharT, _Traits>::__streambuf_type*
+    basic_filebuf<_CharT, _Traits>::
+    setbuf(char_type* __s, streamsize __n)
+    {
+      if (!this->is_open())
+	{
+	  if (__s == 0 && __n == 0)
+	    _M_buf_size = 1;
+	  else if (__s && __n > 0)
+	    {
+	      // This is implementation-defined behavior, and assumes that
+	      // an external char_type array of length __n exists and has
+	      // been pre-allocated. If this is not the case, things will
+	      // quickly blow up. When __n > 1, __n - 1 positions will be
+	      // used for the get area, __n - 1 for the put area and 1
+	      // position to host the overflow char of a full put area.
+	      // When __n == 1, 1 position will be used for the get area
+	      // and 0 for the put area, as in the unbuffered case above.
+	      _M_buf = __s;
+	      _M_buf_size = __n;
+	    }
+	}
+      return this;
+    }
+
+
+  // According to 27.8.1.4 p11 - 13, seekoff should ignore the last
+  // argument (of type openmode).
+  template<typename _CharT, typename _Traits>
+    typename basic_filebuf<_CharT, _Traits>::pos_type
+    basic_filebuf<_CharT, _Traits>::
+    seekoff(off_type __off, ios_base::seekdir __way, ios_base::openmode)
+    {
+      int __width = 0;
+      if (_M_codecvt)
+	__width = _M_codecvt->encoding();
+      if (__width < 0)
+	__width = 0;
+
+      pos_type __ret = pos_type(off_type(-1));
+      const bool __testfail = __off != 0 && __width <= 0;
+      if (this->is_open() && !__testfail)
+	{
+	  // tellg and tellp queries do not affect any state, unless
+	  // ! always_noconv and the put sequence is not empty.
+	  // In that case, determining the position requires converting the
+	  // put sequence. That doesn't use ext_buf, so requires a flush.
+	  bool __no_movement = __way == ios_base::cur && __off == 0
+	    && (!_M_writing || _M_codecvt->always_noconv());
+
+	  // Ditch any pback buffers to avoid confusion.
+	  if (!__no_movement)
+	    _M_destroy_pback();
+
+	  // Correct state at destination. Note that this is the correct
+	  // state for the current position during output, because
+	  // codecvt::unshift() returns the state to the initial state.
+	  // This is also the correct state at the end of the file because
+	  // an unshift sequence should have been written at the end.
+	  __state_type __state = _M_state_beg;
+	  off_type __computed_off = __off * __width;
+	  if (_M_reading && __way == ios_base::cur)
+	    {
+	      __state = _M_state_last;
+	      __computed_off += _M_get_ext_pos(__state);
+	    }
+	  if (!__no_movement)
+	    __ret = _M_seek(__computed_off, __way, __state);
+	  else
+	    {
+	      if (_M_writing)
+		__computed_off = this->pptr() - this->pbase();
+	      
+	      off_type __file_off = _M_file.seekoff(0, ios_base::cur);
+	      if (__file_off != off_type(-1))
+		{
+		  __ret = __file_off + __computed_off;
+		  __ret.state(__state);
+		}
+	    }
+	}
+      return __ret;
+    }
+
+  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+  // 171. Strange seekpos() semantics due to joint position
+  // According to the resolution of DR 171, seekpos should ignore the last
+  // argument (of type openmode).
+  template<typename _CharT, typename _Traits>
+    typename basic_filebuf<_CharT, _Traits>::pos_type
+    basic_filebuf<_CharT, _Traits>::
+    seekpos(pos_type __pos, ios_base::openmode)
+    {
+      pos_type __ret =  pos_type(off_type(-1));
+      if (this->is_open())
+	{
+	  // Ditch any pback buffers to avoid confusion.
+	  _M_destroy_pback();
+	  __ret = _M_seek(off_type(__pos), ios_base::beg, __pos.state());
+	}
+      return __ret;
+    }
+
+  template<typename _CharT, typename _Traits>
+    typename basic_filebuf<_CharT, _Traits>::pos_type
+    basic_filebuf<_CharT, _Traits>::
+    _M_seek(off_type __off, ios_base::seekdir __way, __state_type __state)
+    {
+      pos_type __ret = pos_type(off_type(-1));
+      if (_M_terminate_output())
+	{
+	  off_type __file_off = _M_file.seekoff(__off, __way);
+	  if (__file_off != off_type(-1))
+	    {
+	      _M_reading = false;
+	      _M_writing = false;
+	      _M_ext_next = _M_ext_end = _M_ext_buf;
+	      _M_set_buffer(-1);
+	      _M_state_cur = __state;
+	      __ret = __file_off;
+	      __ret.state(_M_state_cur);
+	    }
+	}
+      return __ret;
+    }
+
+  // Returns the distance from the end of the ext buffer to the point
+  // corresponding to gptr(). This is a negative value. Updates __state
+  // from eback() correspondence to gptr().
+  template<typename _CharT, typename _Traits>
+    int basic_filebuf<_CharT, _Traits>::
+    _M_get_ext_pos(__state_type& __state)
+    {
+      if (_M_codecvt->always_noconv())
+        return this->gptr() - this->egptr();
+      else
+        {
+          // Calculate offset from _M_ext_buf that corresponds to
+          // gptr(). Precondition: __state == _M_state_last, which
+          // corresponds to eback().
+          const int __gptr_off =
+            _M_codecvt->length(__state, _M_ext_buf, _M_ext_next,
+                               this->gptr() - this->eback());
+          return _M_ext_buf + __gptr_off - _M_ext_end;
+        }
+    }
+    
+  template<typename _CharT, typename _Traits>
+    bool
+    basic_filebuf<_CharT, _Traits>::
+    _M_terminate_output()
+    {
+      // Part one: update the output sequence.
+      bool __testvalid = true;
+      if (this->pbase() < this->pptr())
+	{
+	  const int_type __tmp = this->overflow();
+	  if (traits_type::eq_int_type(__tmp, traits_type::eof()))
+	    __testvalid = false;
+	}
+
+      // Part two: output unshift sequence.
+      if (_M_writing && !__check_facet(_M_codecvt).always_noconv()
+	  && __testvalid)
+	{
+	  // Note: this value is arbitrary, since there is no way to
+	  // get the length of the unshift sequence from codecvt,
+	  // without calling unshift.
+	  const size_t __blen = 128;
+	  char __buf[__blen];
+	  codecvt_base::result __r;
+	  streamsize __ilen = 0;
+
+	  do
+	    {
+	      char* __next;
+	      __r = _M_codecvt->unshift(_M_state_cur, __buf,
+					__buf + __blen, __next);
+	      if (__r == codecvt_base::error)
+		__testvalid = false;
+	      else if (__r == codecvt_base::ok ||
+		       __r == codecvt_base::partial)
+		{
+		  __ilen = __next - __buf;
+		  if (__ilen > 0)
+		    {
+		      const streamsize __elen = _M_file.xsputn(__buf, __ilen);
+		      if (__elen != __ilen)
+			__testvalid = false;
+		    }
+		}
+	    }
+	  while (__r == codecvt_base::partial && __ilen > 0 && __testvalid);
+
+	  if (__testvalid)
+	    {
+	      // This second call to overflow() is required by the standard,
+	      // but it's not clear why it's needed, since the output buffer
+	      // should be empty by this point (it should have been emptied
+	      // in the first call to overflow()).
+	      const int_type __tmp = this->overflow();
+	      if (traits_type::eq_int_type(__tmp, traits_type::eof()))
+		__testvalid = false;
+	    }
+	}
+      return __testvalid;
+    }
+
+  template<typename _CharT, typename _Traits>
+    int
+    basic_filebuf<_CharT, _Traits>::
+    sync()
+    {
+      // Make sure that the internal buffer resyncs its idea of
+      // the file position with the external file.
+      int __ret = 0;
+      if (this->pbase() < this->pptr())
+	{
+	  const int_type __tmp = this->overflow();
+	  if (traits_type::eq_int_type(__tmp, traits_type::eof()))
+	    __ret = -1;
+	}
+      return __ret;
+    }
+
+  template<typename _CharT, typename _Traits>
+    void
+    basic_filebuf<_CharT, _Traits>::
+    imbue(const locale& __loc)
+    {
+      bool __testvalid = true;
+
+      const __codecvt_type* _M_codecvt_tmp = 0;
+      if (__builtin_expect(has_facet<__codecvt_type>(__loc), true))
+	_M_codecvt_tmp = &use_facet<__codecvt_type>(__loc);
+
+      if (this->is_open())
+	{
+	  // encoding() == -1 is ok only at the beginning.
+	  if ((_M_reading || _M_writing)
+	      && __check_facet(_M_codecvt).encoding() == -1)
+	    __testvalid = false;
+	  else
+	    {
+	      if (_M_reading)
+		{
+		  if (__check_facet(_M_codecvt).always_noconv())
+		    {
+		      if (_M_codecvt_tmp
+			  && !__check_facet(_M_codecvt_tmp).always_noconv())
+			__testvalid = this->seekoff(0, ios_base::cur, _M_mode)
+			              != pos_type(off_type(-1));
+		    }
+		  else
+		    {
+		      // External position corresponding to gptr().
+		      _M_ext_next = _M_ext_buf
+			+ _M_codecvt->length(_M_state_last, _M_ext_buf,
+					     _M_ext_next,
+					     this->gptr() - this->eback());
+		      const streamsize __remainder = _M_ext_end - _M_ext_next;
+		      if (__remainder)
+			__builtin_memmove(_M_ext_buf, _M_ext_next, __remainder);
+
+		      _M_ext_next = _M_ext_buf;
+		      _M_ext_end = _M_ext_buf + __remainder;
+		      _M_set_buffer(-1);
+		      _M_state_last = _M_state_cur = _M_state_beg;
+		    }
+		}
+	      else if (_M_writing && (__testvalid = _M_terminate_output()))
+		_M_set_buffer(-1);
+	    }
+	}
+
+      if (__testvalid)
+	_M_codecvt = _M_codecvt_tmp;
+      else
+	_M_codecvt = 0;
+    }
+
+  // Inhibit implicit instantiations for required instantiations,
+  // which are defined via explicit instantiations elsewhere.
+#if _GLIBCXX_EXTERN_TEMPLATE
+  extern template class basic_filebuf<char>;
+  extern template class basic_ifstream<char>;
+  extern template class basic_ofstream<char>;
+  extern template class basic_fstream<char>;
+
+#ifdef _GLIBCXX_USE_WCHAR_T
+  extern template class basic_filebuf<wchar_t>;
+  extern template class basic_ifstream<wchar_t>;
+  extern template class basic_ofstream<wchar_t>;
+  extern template class basic_fstream<wchar_t>;
+#endif
+#endif
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@fstream.tcc.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@fstream.tcc.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@functexcept.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@functexcept.h
new file mode 100644
index 0000000000000000000000000000000000000000..a78a17b2e049588418e05ae94380c7d5f1b06a3a
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@functexcept.h
@@ -0,0 +1,118 @@
+// Function-Based Exception Support -*- C++ -*-
+
+// Copyright (C) 2001-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/functexcept.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{exception}
+ *
+ *  This header provides support for -fno-exceptions.
+ */
+
+//
+// ISO C++ 14882: 19.1  Exception classes
+//
+
+#ifndef _FUNCTEXCEPT_H
+#define _FUNCTEXCEPT_H 1
+
+#include <bits/c++config.h>
+#include <bits/exception_defines.h>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  // Helper for exception objects in <except>
+  void
+  __throw_bad_exception(void) __attribute__((__noreturn__));
+
+  // Helper for exception objects in <new>
+  void
+  __throw_bad_alloc(void) __attribute__((__noreturn__));
+
+  void
+  __throw_bad_array_new_length(void) __attribute__((__noreturn__));
+
+  // Helper for exception objects in <typeinfo>
+  void
+  __throw_bad_cast(void) __attribute__((__noreturn__));
+
+  void
+  __throw_bad_typeid(void) __attribute__((__noreturn__));
+
+  // Helpers for exception objects in <stdexcept>
+  void
+  __throw_logic_error(const char*) __attribute__((__noreturn__));
+
+  void
+  __throw_domain_error(const char*) __attribute__((__noreturn__));
+
+  void
+  __throw_invalid_argument(const char*) __attribute__((__noreturn__));
+
+  void
+  __throw_length_error(const char*) __attribute__((__noreturn__));
+
+  void
+  __throw_out_of_range(const char*) __attribute__((__noreturn__));
+
+  void
+  __throw_out_of_range_fmt(const char*, ...) __attribute__((__noreturn__))
+    __attribute__((__format__(__gnu_printf__, 1, 2)));
+
+  void
+  __throw_runtime_error(const char*) __attribute__((__noreturn__));
+
+  void
+  __throw_range_error(const char*) __attribute__((__noreturn__));
+
+  void
+  __throw_overflow_error(const char*) __attribute__((__noreturn__));
+
+  void
+  __throw_underflow_error(const char*) __attribute__((__noreturn__));
+
+  // Helpers for exception objects in <ios>
+  void
+  __throw_ios_failure(const char*) __attribute__((__noreturn__));
+
+  void
+  __throw_ios_failure(const char*, int) __attribute__((__noreturn__));
+
+  // Helpers for exception objects in <system_error>
+  void
+  __throw_system_error(int) __attribute__((__noreturn__));
+
+  // Helpers for exception objects in <future>
+  void
+  __throw_future_error(int) __attribute__((__noreturn__));
+
+  // Helpers for exception objects in <functional>
+  void
+  __throw_bad_function_call() __attribute__((__noreturn__));
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@functexcept.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@functexcept.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@functional_hash.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@functional_hash.h
new file mode 100644
index 0000000000000000000000000000000000000000..c00113eff838283f509a798bf7beaaca7d314a4e
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@functional_hash.h
@@ -0,0 +1,298 @@
+// functional_hash.h header -*- C++ -*-
+
+// Copyright (C) 2007-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/functional_hash.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{functional}
+ */
+
+#ifndef _FUNCTIONAL_HASH_H
+#define _FUNCTIONAL_HASH_H 1
+
+#pragma GCC system_header
+
+#include <type_traits>
+#include <bits/hash_bytes.h>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /** @defgroup hashes Hashes
+   *  @ingroup functors
+   *
+   *   Hashing functors taking a variable type and returning a @c std::size_t.
+   *
+   *  @{
+   */
+
+  template<typename _Result, typename _Arg>
+    struct __hash_base
+    {
+      typedef _Result     result_type _GLIBCXX17_DEPRECATED;
+      typedef _Arg      argument_type _GLIBCXX17_DEPRECATED;
+    };
+
+  /// Primary class template hash.
+  template<typename _Tp>
+    struct hash;
+
+  template<typename _Tp, typename = void>
+    struct __poison_hash
+    {
+      static constexpr bool __enable_hash_call = false;
+    private:
+      // Private rather than deleted to be non-trivially-copyable.
+      __poison_hash(__poison_hash&&);
+      ~__poison_hash();
+    };
+
+  template<typename _Tp>
+    struct __poison_hash<_Tp, __void_t<decltype(hash<_Tp>()(declval<_Tp>()))>>
+    {
+      static constexpr bool __enable_hash_call = true;
+    };
+
+  // Helper struct for SFINAE-poisoning non-enum types.
+  template<typename _Tp, bool = is_enum<_Tp>::value>
+    struct __hash_enum
+    {
+    private:
+      // Private rather than deleted to be non-trivially-copyable.
+      __hash_enum(__hash_enum&&);
+      ~__hash_enum();
+    };
+
+  // Helper struct for hash with enum types.
+  template<typename _Tp>
+    struct __hash_enum<_Tp, true> : public __hash_base<size_t, _Tp>
+    {
+      size_t
+      operator()(_Tp __val) const noexcept
+      {
+       using __type = typename underlying_type<_Tp>::type;
+       return hash<__type>{}(static_cast<__type>(__val));
+      }
+    };
+
+  /// Primary class template hash, usable for enum types only.
+  // Use with non-enum types still SFINAES.
+  template<typename _Tp>
+    struct hash : __hash_enum<_Tp>
+    { };
+
+  /// Partial specializations for pointer types.
+  template<typename _Tp>
+    struct hash<_Tp*> : public __hash_base<size_t, _Tp*>
+    {
+      size_t
+      operator()(_Tp* __p) const noexcept
+      { return reinterpret_cast<size_t>(__p); }
+    };
+
+  // Explicit specializations for integer types.
+#define _Cxx_hashtable_define_trivial_hash(_Tp) 	\
+  template<>						\
+    struct hash<_Tp> : public __hash_base<size_t, _Tp>  \
+    {                                                   \
+      size_t                                            \
+      operator()(_Tp __val) const noexcept              \
+      { return static_cast<size_t>(__val); }            \
+    };
+
+  /// Explicit specialization for bool.
+  _Cxx_hashtable_define_trivial_hash(bool)
+
+  /// Explicit specialization for char.
+  _Cxx_hashtable_define_trivial_hash(char)
+
+  /// Explicit specialization for signed char.
+  _Cxx_hashtable_define_trivial_hash(signed char)
+
+  /// Explicit specialization for unsigned char.
+  _Cxx_hashtable_define_trivial_hash(unsigned char)
+
+  /// Explicit specialization for wchar_t.
+  _Cxx_hashtable_define_trivial_hash(wchar_t)
+
+#ifdef _GLIBCXX_USE_CHAR8_T
+  /// Explicit specialization for char8_t.
+  _Cxx_hashtable_define_trivial_hash(char8_t)
+#endif
+
+  /// Explicit specialization for char16_t.
+  _Cxx_hashtable_define_trivial_hash(char16_t)
+
+  /// Explicit specialization for char32_t.
+  _Cxx_hashtable_define_trivial_hash(char32_t)
+
+  /// Explicit specialization for short.
+  _Cxx_hashtable_define_trivial_hash(short)
+
+  /// Explicit specialization for int.
+  _Cxx_hashtable_define_trivial_hash(int)
+
+  /// Explicit specialization for long.
+  _Cxx_hashtable_define_trivial_hash(long)
+
+  /// Explicit specialization for long long.
+  _Cxx_hashtable_define_trivial_hash(long long)
+
+  /// Explicit specialization for unsigned short.
+  _Cxx_hashtable_define_trivial_hash(unsigned short)
+
+  /// Explicit specialization for unsigned int.
+  _Cxx_hashtable_define_trivial_hash(unsigned int)
+
+  /// Explicit specialization for unsigned long.
+  _Cxx_hashtable_define_trivial_hash(unsigned long)
+
+  /// Explicit specialization for unsigned long long.
+  _Cxx_hashtable_define_trivial_hash(unsigned long long)
+
+#ifdef __GLIBCXX_TYPE_INT_N_0
+  __extension__
+  _Cxx_hashtable_define_trivial_hash(__GLIBCXX_TYPE_INT_N_0)
+  __extension__
+  _Cxx_hashtable_define_trivial_hash(__GLIBCXX_TYPE_INT_N_0 unsigned)
+#endif
+#ifdef __GLIBCXX_TYPE_INT_N_1
+  __extension__
+  _Cxx_hashtable_define_trivial_hash(__GLIBCXX_TYPE_INT_N_1)
+  __extension__
+  _Cxx_hashtable_define_trivial_hash(__GLIBCXX_TYPE_INT_N_1 unsigned)
+#endif
+#ifdef __GLIBCXX_TYPE_INT_N_2
+  __extension__
+  _Cxx_hashtable_define_trivial_hash(__GLIBCXX_TYPE_INT_N_2)
+  __extension__
+  _Cxx_hashtable_define_trivial_hash(__GLIBCXX_TYPE_INT_N_2 unsigned)
+#endif
+#ifdef __GLIBCXX_TYPE_INT_N_3
+  __extension__
+  _Cxx_hashtable_define_trivial_hash(__GLIBCXX_TYPE_INT_N_3)
+  __extension__
+  _Cxx_hashtable_define_trivial_hash(__GLIBCXX_TYPE_INT_N_3 unsigned)
+#endif
+
+#undef _Cxx_hashtable_define_trivial_hash
+
+  struct _Hash_impl
+  {
+    static size_t
+    hash(const void* __ptr, size_t __clength,
+	 size_t __seed = static_cast<size_t>(0xc70f6907UL))
+    { return _Hash_bytes(__ptr, __clength, __seed); }
+
+    template<typename _Tp>
+      static size_t
+      hash(const _Tp& __val)
+      { return hash(&__val, sizeof(__val)); }
+
+    template<typename _Tp>
+      static size_t
+      __hash_combine(const _Tp& __val, size_t __hash)
+      { return hash(&__val, sizeof(__val), __hash); }
+  };
+
+  // A hash function similar to FNV-1a (see PR59406 for how it differs).
+  struct _Fnv_hash_impl
+  {
+    static size_t
+    hash(const void* __ptr, size_t __clength,
+	 size_t __seed = static_cast<size_t>(2166136261UL))
+    { return _Fnv_hash_bytes(__ptr, __clength, __seed); }
+
+    template<typename _Tp>
+      static size_t
+      hash(const _Tp& __val)
+      { return hash(&__val, sizeof(__val)); }
+
+    template<typename _Tp>
+      static size_t
+      __hash_combine(const _Tp& __val, size_t __hash)
+      { return hash(&__val, sizeof(__val), __hash); }
+  };
+
+  /// Specialization for float.
+  template<>
+    struct hash<float> : public __hash_base<size_t, float>
+    {
+      size_t
+      operator()(float __val) const noexcept
+      {
+	// 0 and -0 both hash to zero.
+	return __val != 0.0f ? std::_Hash_impl::hash(__val) : 0;
+      }
+    };
+
+  /// Specialization for double.
+  template<>
+    struct hash<double> : public __hash_base<size_t, double>
+    {
+      size_t
+      operator()(double __val) const noexcept
+      {
+	// 0 and -0 both hash to zero.
+	return __val != 0.0 ? std::_Hash_impl::hash(__val) : 0;
+      }
+    };
+
+  /// Specialization for long double.
+  template<>
+    struct hash<long double>
+    : public __hash_base<size_t, long double>
+    {
+      _GLIBCXX_PURE size_t
+      operator()(long double __val) const noexcept;
+    };
+
+#if __cplusplus >= 201703L
+  template<>
+    struct hash<nullptr_t> : public __hash_base<size_t, nullptr_t>
+    {
+      size_t
+      operator()(nullptr_t) const noexcept
+      { return 0; }
+    };
+#endif
+
+  /// @} group hashes
+
+  // Hint about performance of hash functor. If not fast the hash-based
+  // containers will cache the hash code.
+  // Default behavior is to consider that hashers are fast unless specified
+  // otherwise.
+  template<typename _Hash>
+    struct __is_fast_hash : public std::true_type
+    { };
+
+  template<>
+    struct __is_fast_hash<hash<long double>> : public std::false_type
+    { };
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif // _FUNCTIONAL_HASH_H
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@gslice.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@gslice.h
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@@ -0,0 +1,185 @@
+// The template and inlines for the -*- C++ -*- gslice class.
+
+// Copyright (C) 1997-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/gslice.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{valarray}
+ */
+
+// Written by Gabriel Dos Reis <Gabriel.Dos-Reis@DPTMaths.ENS-Cachan.Fr>
+
+#ifndef _GSLICE_H
+#define _GSLICE_H 1
+
+#pragma GCC system_header
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /**
+   * @addtogroup numeric_arrays
+   * @{
+   */
+
+  /**
+   *  @brief  Class defining multi-dimensional subset of an array.
+   *
+   *  The slice class represents a multi-dimensional subset of an array,
+   *  specified by three parameter sets: start offset, size array, and stride
+   *  array.  The start offset is the index of the first element of the array
+   *  that is part of the subset.  The size and stride array describe each
+   *  dimension of the slice.  Size is the number of elements in that
+   *  dimension, and stride is the distance in the array between successive
+   *  elements in that dimension.  Each dimension's size and stride is taken
+   *  to begin at an array element described by the previous dimension.  The
+   *  size array and stride array must be the same size.
+   *
+   *  For example, if you have offset==3, stride[0]==11, size[1]==3,
+   *  stride[1]==3, then slice[0,0]==array[3], slice[0,1]==array[6],
+   *  slice[0,2]==array[9], slice[1,0]==array[14], slice[1,1]==array[17],
+   *  slice[1,2]==array[20].
+   */
+  class gslice
+  {
+  public:
+    ///  Construct an empty slice.
+    gslice();
+
+    /**
+     *  @brief  Construct a slice.
+     *
+     *  Constructs a slice with as many dimensions as the length of the @a l
+     *  and @a s arrays.
+     *
+     *  @param  __o  Offset in array of first element.
+     *  @param  __l  Array of dimension lengths.
+     *  @param  __s  Array of dimension strides between array elements.
+     */
+    gslice(size_t __o, const valarray<size_t>& __l, 
+	   const valarray<size_t>& __s);
+
+    // XXX: the IS says the copy-ctor and copy-assignment operators are
+    //      synthesized by the compiler but they are just unsuitable
+    //      for a ref-counted semantic
+    ///  Copy constructor.
+    gslice(const gslice&);
+
+    ///  Destructor.
+    ~gslice();
+
+    // XXX: See the note above.
+    ///  Assignment operator.
+    gslice& operator=(const gslice&);
+
+    ///  Return array offset of first slice element.
+    size_t           start() const;
+
+    ///  Return array of sizes of slice dimensions.
+    valarray<size_t> size() const;
+    
+    ///  Return array of array strides for each dimension.
+    valarray<size_t> stride() const;
+
+  private:
+    struct _Indexer
+    {
+      size_t _M_count;
+      size_t _M_start;
+      valarray<size_t> _M_size;
+      valarray<size_t> _M_stride;
+      valarray<size_t> _M_index; // Linear array of referenced indices
+
+      _Indexer()
+      : _M_count(1), _M_start(0), _M_size(), _M_stride(), _M_index() {}
+
+      _Indexer(size_t, const valarray<size_t>&,
+	       const valarray<size_t>&);
+
+      void
+      _M_increment_use()
+      { ++_M_count; }
+      
+      size_t
+      _M_decrement_use()
+      { return --_M_count; }
+    };
+
+    _Indexer* _M_index;
+
+    template<typename _Tp> friend class valarray;
+  };
+
+  inline size_t
+  gslice::start() const
+  { return _M_index ? _M_index->_M_start : 0; }
+
+  inline valarray<size_t>
+  gslice::size() const
+  { return _M_index ? _M_index->_M_size : valarray<size_t>(); }
+
+  inline valarray<size_t>
+  gslice::stride() const
+  { return _M_index ? _M_index->_M_stride : valarray<size_t>(); }
+
+  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+  // 543. valarray slice default constructor
+  inline
+  gslice::gslice()
+  : _M_index(new gslice::_Indexer()) {}
+
+  inline
+  gslice::gslice(size_t __o, const valarray<size_t>& __l,
+		 const valarray<size_t>& __s)
+  : _M_index(new gslice::_Indexer(__o, __l, __s)) {}
+
+  inline
+  gslice::gslice(const gslice& __g)
+  : _M_index(__g._M_index)
+  { if (_M_index) _M_index->_M_increment_use(); }
+
+  inline
+  gslice::~gslice()
+  {
+    if (_M_index && _M_index->_M_decrement_use() == 0)
+      delete _M_index;
+  }
+
+  inline gslice&
+  gslice::operator=(const gslice& __g)
+  {
+    if (__g._M_index)
+      __g._M_index->_M_increment_use();
+    if (_M_index && _M_index->_M_decrement_use() == 0)
+      delete _M_index;
+    _M_index = __g._M_index;
+    return *this;
+  }
+
+  /// @} group numeric_arrays
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif /* _GSLICE_H */
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@gslice_array.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@gslice_array.h
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@@ -0,0 +1,223 @@
+// The template and inlines for the -*- C++ -*- gslice_array class.
+
+// Copyright (C) 1997-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/gslice_array.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{valarray}
+ */
+
+// Written by Gabriel Dos Reis <Gabriel.Dos-Reis@DPTMaths.ENS-Cachan.Fr>
+
+#ifndef _GSLICE_ARRAY_H
+#define _GSLICE_ARRAY_H 1
+
+#pragma GCC system_header
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /**
+   * @addtogroup numeric_arrays
+   * @{
+   */
+
+  /**
+   *  @brief  Reference to multi-dimensional subset of an array.
+   *
+   *  A gslice_array is a reference to the actual elements of an array
+   *  specified by a gslice.  The way to get a gslice_array is to call
+   *  operator[](gslice) on a valarray.  The returned gslice_array then
+   *  permits carrying operations out on the referenced subset of elements in
+   *  the original valarray.  For example, operator+=(valarray) will add
+   *  values to the subset of elements in the underlying valarray this
+   *  gslice_array refers to.
+   *
+   *  @param  Tp  Element type.
+   */
+  template<typename _Tp>
+    class gslice_array
+    {
+    public:
+      typedef _Tp value_type;
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 253. valarray helper functions are almost entirely useless
+
+      ///  Copy constructor.  Both slices refer to the same underlying array.
+      gslice_array(const gslice_array&);
+
+      ///  Assignment operator.  Assigns slice elements to corresponding
+      ///  elements of @a a.
+      gslice_array& operator=(const gslice_array&);
+
+      ///  Assign slice elements to corresponding elements of @a v.
+      void operator=(const valarray<_Tp>&) const;
+      ///  Multiply slice elements by corresponding elements of @a v.
+      void operator*=(const valarray<_Tp>&) const;
+      ///  Divide slice elements by corresponding elements of @a v.
+      void operator/=(const valarray<_Tp>&) const;
+      ///  Modulo slice elements by corresponding elements of @a v.
+      void operator%=(const valarray<_Tp>&) const;
+      ///  Add corresponding elements of @a v to slice elements.
+      void operator+=(const valarray<_Tp>&) const;
+      ///  Subtract corresponding elements of @a v from slice elements.
+      void operator-=(const valarray<_Tp>&) const;
+      ///  Logical xor slice elements with corresponding elements of @a v.
+      void operator^=(const valarray<_Tp>&) const;
+      ///  Logical and slice elements with corresponding elements of @a v.
+      void operator&=(const valarray<_Tp>&) const;
+      ///  Logical or slice elements with corresponding elements of @a v.
+      void operator|=(const valarray<_Tp>&) const;
+      ///  Left shift slice elements by corresponding elements of @a v.
+      void operator<<=(const valarray<_Tp>&) const;
+      ///  Right shift slice elements by corresponding elements of @a v.
+      void operator>>=(const valarray<_Tp>&) const;
+      ///  Assign all slice elements to @a t.
+      void operator=(const _Tp&) const;
+
+      template<class _Dom>
+        void operator=(const _Expr<_Dom, _Tp>&) const;
+      template<class _Dom>
+        void operator*=(const _Expr<_Dom, _Tp>&) const;
+      template<class _Dom>
+        void operator/=(const _Expr<_Dom, _Tp>&) const;
+      template<class _Dom>
+        void operator%=(const _Expr<_Dom, _Tp>&) const;
+      template<class _Dom>
+        void operator+=(const _Expr<_Dom, _Tp>&) const;
+      template<class _Dom>
+        void operator-=(const _Expr<_Dom, _Tp>&) const;
+      template<class _Dom>
+        void operator^=(const _Expr<_Dom, _Tp>&) const;
+      template<class _Dom>
+        void operator&=(const _Expr<_Dom, _Tp>&) const;
+      template<class _Dom>
+        void operator|=(const _Expr<_Dom, _Tp>&) const;
+      template<class _Dom>
+        void operator<<=(const _Expr<_Dom, _Tp>&) const;
+      template<class _Dom>
+        void operator>>=(const _Expr<_Dom, _Tp>&) const;
+
+    private:
+      _Array<_Tp>    _M_array;
+      const valarray<size_t>& _M_index;
+
+      friend class valarray<_Tp>;
+
+      gslice_array(_Array<_Tp>, const valarray<size_t>&);
+
+#if __cplusplus < 201103L
+      // not implemented
+      gslice_array();
+#else
+    public:
+      gslice_array() = delete;
+#endif
+    };
+
+  template<typename _Tp>
+    inline
+    gslice_array<_Tp>::gslice_array(_Array<_Tp> __a,
+				    const valarray<size_t>& __i)
+    : _M_array(__a), _M_index(__i) {}
+
+  template<typename _Tp>
+    inline
+    gslice_array<_Tp>::gslice_array(const gslice_array<_Tp>& __a)
+    : _M_array(__a._M_array), _M_index(__a._M_index) {}
+
+  template<typename _Tp>
+    inline gslice_array<_Tp>&
+    gslice_array<_Tp>::operator=(const gslice_array<_Tp>& __a)
+    {
+      std::__valarray_copy(_Array<_Tp>(__a._M_array),
+			   _Array<size_t>(__a._M_index), _M_index.size(),
+			   _M_array, _Array<size_t>(_M_index));
+      return *this;
+    }
+
+  template<typename _Tp>
+    inline void
+    gslice_array<_Tp>::operator=(const _Tp& __t) const
+    {
+      std::__valarray_fill(_M_array, _Array<size_t>(_M_index),
+			   _M_index.size(), __t);
+    }
+
+  template<typename _Tp>
+    inline void
+    gslice_array<_Tp>::operator=(const valarray<_Tp>& __v) const
+    {
+      std::__valarray_copy(_Array<_Tp>(__v), __v.size(),
+			   _M_array, _Array<size_t>(_M_index));
+    }
+
+  template<typename _Tp>
+    template<class _Dom>
+      inline void
+      gslice_array<_Tp>::operator=(const _Expr<_Dom, _Tp>& __e) const
+      {
+	std::__valarray_copy (__e, _M_index.size(), _M_array,
+			      _Array<size_t>(_M_index));
+      }
+
+#undef _DEFINE_VALARRAY_OPERATOR
+#define _DEFINE_VALARRAY_OPERATOR(_Op, _Name)				\
+  template<typename _Tp>						\
+    inline void								\
+    gslice_array<_Tp>::operator _Op##=(const valarray<_Tp>& __v) const	\
+    {									\
+      _Array_augmented_##_Name(_M_array, _Array<size_t>(_M_index),	\
+			       _Array<_Tp>(__v), __v.size());		\
+    }									\
+									\
+  template<typename _Tp>                                                \
+    template<class _Dom>				                \
+      inline void							\
+      gslice_array<_Tp>::operator _Op##= (const _Expr<_Dom, _Tp>& __e) const\
+      {									\
+	_Array_augmented_##_Name(_M_array, _Array<size_t>(_M_index), __e,\
+				 _M_index.size());			\
+      }
+
+_DEFINE_VALARRAY_OPERATOR(*, __multiplies)
+_DEFINE_VALARRAY_OPERATOR(/, __divides)
+_DEFINE_VALARRAY_OPERATOR(%, __modulus)
+_DEFINE_VALARRAY_OPERATOR(+, __plus)
+_DEFINE_VALARRAY_OPERATOR(-, __minus)
+_DEFINE_VALARRAY_OPERATOR(^, __bitwise_xor)
+_DEFINE_VALARRAY_OPERATOR(&, __bitwise_and)
+_DEFINE_VALARRAY_OPERATOR(|, __bitwise_or)
+_DEFINE_VALARRAY_OPERATOR(<<, __shift_left)
+_DEFINE_VALARRAY_OPERATOR(>>, __shift_right)
+
+#undef _DEFINE_VALARRAY_OPERATOR
+
+  /// @} group numeric_arrays
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif /* _GSLICE_ARRAY_H */
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@hash_bytes.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@hash_bytes.h
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@@ -0,0 +1,59 @@
+// Declarations for hash functions. -*- C++ -*-
+
+// Copyright (C) 2010-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/hash_bytes.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{functional}
+ */
+
+#ifndef _HASH_BYTES_H
+#define _HASH_BYTES_H 1
+
+#pragma GCC system_header
+
+#include <bits/c++config.h>
+
+namespace std
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  // Hash function implementation for the nontrivial specialization.
+  // All of them are based on a primitive that hashes a pointer to a
+  // byte array. The actual hash algorithm is not guaranteed to stay
+  // the same from release to release -- it may be updated or tuned to
+  // improve hash quality or speed.
+  size_t
+  _Hash_bytes(const void* __ptr, size_t __len, size_t __seed);
+
+  // A similar hash primitive, using the FNV hash algorithm. This
+  // algorithm is guaranteed to stay the same from release to release.
+  // (although it might not produce the same values on different
+  // machines.)
+  size_t
+  _Fnv_hash_bytes(const void* __ptr, size_t __len, size_t __seed);
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif
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@@ -0,0 +1,2700 @@
+// hashtable.h header -*- C++ -*-
+
+// Copyright (C) 2007-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/hashtable.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{unordered_map, unordered_set}
+ */
+
+#ifndef _HASHTABLE_H
+#define _HASHTABLE_H 1
+
+#pragma GCC system_header
+
+#include <bits/hashtable_policy.h>
+#include <bits/enable_special_members.h>
+#if __cplusplus > 201402L
+# include <bits/node_handle.h>
+#endif
+#include <bits/functional_hash.h>
+#include <bits/stl_function.h> // equal_to, _Identity, _Select1st
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+/// @cond undocumented
+
+  template<typename _Tp, typename _Hash>
+    using __cache_default
+      =  __not_<__and_<// Do not cache for fast hasher.
+		       __is_fast_hash<_Hash>,
+		       // Mandatory to have erase not throwing.
+		       __is_nothrow_invocable<const _Hash&, const _Tp&>>>;
+
+  // Helper to conditionally delete the default constructor.
+  // The _Hash_node_base type is used to distinguish this specialization
+  // from any other potentially-overlapping subobjects of the hashtable.
+  template<typename _Equal, typename _Hash, typename _Allocator>
+    using _Hashtable_enable_default_ctor
+      = _Enable_default_constructor<__and_<is_default_constructible<_Equal>,
+				       is_default_constructible<_Hash>,
+				       is_default_constructible<_Allocator>>{},
+				    __detail::_Hash_node_base>;
+
+  /**
+   *  Primary class template _Hashtable.
+   *
+   *  @ingroup hashtable-detail
+   *
+   *  @tparam _Value  CopyConstructible type.
+   *
+   *  @tparam _Key    CopyConstructible type.
+   *
+   *  @tparam _Alloc  An allocator type
+   *  ([lib.allocator.requirements]) whose _Alloc::value_type is
+   *  _Value.  As a conforming extension, we allow for
+   *  _Alloc::value_type != _Value.
+   *
+   *  @tparam _ExtractKey  Function object that takes an object of type
+   *  _Value and returns a value of type _Key.
+   *
+   *  @tparam _Equal  Function object that takes two objects of type k
+   *  and returns a bool-like value that is true if the two objects
+   *  are considered equal.
+   *
+   *  @tparam _Hash  The hash function. A unary function object with
+   *  argument type _Key and result type size_t. Return values should
+   *  be distributed over the entire range [0, numeric_limits<size_t>:::max()].
+   *
+   *  @tparam _RangeHash  The range-hashing function (in the terminology of
+   *  Tavori and Dreizin).  A binary function object whose argument
+   *  types and result type are all size_t.  Given arguments r and N,
+   *  the return value is in the range [0, N).
+   *
+   *  @tparam _Unused  Not used.
+   *
+   *  @tparam _RehashPolicy  Policy class with three members, all of
+   *  which govern the bucket count. _M_next_bkt(n) returns a bucket
+   *  count no smaller than n.  _M_bkt_for_elements(n) returns a
+   *  bucket count appropriate for an element count of n.
+   *  _M_need_rehash(n_bkt, n_elt, n_ins) determines whether, if the
+   *  current bucket count is n_bkt and the current element count is
+   *  n_elt, we need to increase the bucket count for n_ins insertions.
+   *  If so, returns make_pair(true, n), where n is the new bucket count. If
+   *  not, returns make_pair(false, <anything>)
+   *
+   *  @tparam _Traits  Compile-time class with three boolean
+   *  std::integral_constant members:  __cache_hash_code, __constant_iterators,
+   *   __unique_keys.
+   *
+   *  Each _Hashtable data structure has:
+   *
+   *  - _Bucket[]       _M_buckets
+   *  - _Hash_node_base _M_before_begin
+   *  - size_type       _M_bucket_count
+   *  - size_type       _M_element_count
+   *
+   *  with _Bucket being _Hash_node_base* and _Hash_node containing:
+   *
+   *  - _Hash_node*   _M_next
+   *  - Tp            _M_value
+   *  - size_t        _M_hash_code if cache_hash_code is true
+   *
+   *  In terms of Standard containers the hashtable is like the aggregation of:
+   *
+   *  - std::forward_list<_Node> containing the elements
+   *  - std::vector<std::forward_list<_Node>::iterator> representing the buckets
+   *
+   *  The non-empty buckets contain the node before the first node in the
+   *  bucket. This design makes it possible to implement something like a
+   *  std::forward_list::insert_after on container insertion and
+   *  std::forward_list::erase_after on container erase
+   *  calls. _M_before_begin is equivalent to
+   *  std::forward_list::before_begin. Empty buckets contain
+   *  nullptr.  Note that one of the non-empty buckets contains
+   *  &_M_before_begin which is not a dereferenceable node so the
+   *  node pointer in a bucket shall never be dereferenced, only its
+   *  next node can be.
+   *
+   *  Walking through a bucket's nodes requires a check on the hash code to
+   *  see if each node is still in the bucket. Such a design assumes a
+   *  quite efficient hash functor and is one of the reasons it is
+   *  highly advisable to set __cache_hash_code to true.
+   *
+   *  The container iterators are simply built from nodes. This way
+   *  incrementing the iterator is perfectly efficient independent of
+   *  how many empty buckets there are in the container.
+   *
+   *  On insert we compute the element's hash code and use it to find the
+   *  bucket index. If the element must be inserted in an empty bucket
+   *  we add it at the beginning of the singly linked list and make the
+   *  bucket point to _M_before_begin. The bucket that used to point to
+   *  _M_before_begin, if any, is updated to point to its new before
+   *  begin node.
+   *
+   *  On erase, the simple iterator design requires using the hash
+   *  functor to get the index of the bucket to update. For this
+   *  reason, when __cache_hash_code is set to false the hash functor must
+   *  not throw and this is enforced by a static assertion.
+   *
+   *  Functionality is implemented by decomposition into base classes,
+   *  where the derived _Hashtable class is used in _Map_base,
+   *  _Insert, _Rehash_base, and _Equality base classes to access the
+   *  "this" pointer. _Hashtable_base is used in the base classes as a
+   *  non-recursive, fully-completed-type so that detailed nested type
+   *  information, such as iterator type and node type, can be
+   *  used. This is similar to the "Curiously Recurring Template
+   *  Pattern" (CRTP) technique, but uses a reconstructed, not
+   *  explicitly passed, template pattern.
+   *
+   *  Base class templates are: 
+   *    - __detail::_Hashtable_base
+   *    - __detail::_Map_base
+   *    - __detail::_Insert
+   *    - __detail::_Rehash_base
+   *    - __detail::_Equality
+   */
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    class _Hashtable
+    : public __detail::_Hashtable_base<_Key, _Value, _ExtractKey, _Equal,
+				       _Hash, _RangeHash, _Unused, _Traits>,
+      public __detail::_Map_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+				 _Hash, _RangeHash, _Unused,
+				 _RehashPolicy, _Traits>,
+      public __detail::_Insert<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+			       _Hash, _RangeHash, _Unused,
+			       _RehashPolicy, _Traits>,
+      public __detail::_Rehash_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+				    _Hash, _RangeHash, _Unused,
+				    _RehashPolicy, _Traits>,
+      public __detail::_Equality<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+				 _Hash, _RangeHash, _Unused,
+				 _RehashPolicy, _Traits>,
+      private __detail::_Hashtable_alloc<
+	__alloc_rebind<_Alloc,
+		       __detail::_Hash_node<_Value,
+					    _Traits::__hash_cached::value>>>,
+      private _Hashtable_enable_default_ctor<_Equal, _Hash, _Alloc>
+    {
+      static_assert(is_same<typename remove_cv<_Value>::type, _Value>::value,
+	  "unordered container must have a non-const, non-volatile value_type");
+#if __cplusplus > 201703L || defined __STRICT_ANSI__
+      static_assert(is_same<typename _Alloc::value_type, _Value>{},
+	  "unordered container must have the same value_type as its allocator");
+#endif
+
+      using __traits_type = _Traits;
+      using __hash_cached = typename __traits_type::__hash_cached;
+      using __constant_iterators = typename __traits_type::__constant_iterators;
+      using __node_type = __detail::_Hash_node<_Value, __hash_cached::value>;
+      using __node_alloc_type = __alloc_rebind<_Alloc, __node_type>;
+
+      using __hashtable_alloc = __detail::_Hashtable_alloc<__node_alloc_type>;
+
+      using __node_value_type =
+	__detail::_Hash_node_value<_Value, __hash_cached::value>;
+      using __node_ptr = typename __hashtable_alloc::__node_ptr;
+      using __value_alloc_traits =
+	typename __hashtable_alloc::__value_alloc_traits;
+      using __node_alloc_traits =
+	typename __hashtable_alloc::__node_alloc_traits;
+      using __node_base = typename __hashtable_alloc::__node_base;
+      using __node_base_ptr = typename __hashtable_alloc::__node_base_ptr;
+      using __buckets_ptr = typename __hashtable_alloc::__buckets_ptr;
+
+      using __insert_base = __detail::_Insert<_Key, _Value, _Alloc, _ExtractKey,
+					      _Equal, _Hash,
+					      _RangeHash, _Unused,
+					      _RehashPolicy, _Traits>;
+      using __enable_default_ctor
+	= _Hashtable_enable_default_ctor<_Equal, _Hash, _Alloc>;
+
+    public:
+      typedef _Key						key_type;
+      typedef _Value						value_type;
+      typedef _Alloc						allocator_type;
+      typedef _Equal						key_equal;
+
+      // mapped_type, if present, comes from _Map_base.
+      // hasher, if present, comes from _Hash_code_base/_Hashtable_base.
+      typedef typename __value_alloc_traits::pointer		pointer;
+      typedef typename __value_alloc_traits::const_pointer	const_pointer;
+      typedef value_type&					reference;
+      typedef const value_type&					const_reference;
+
+      using iterator = typename __insert_base::iterator;
+
+      using const_iterator = typename __insert_base::const_iterator;
+
+      using local_iterator = __detail::_Local_iterator<key_type, _Value,
+			_ExtractKey, _Hash, _RangeHash, _Unused,
+					     __constant_iterators::value,
+					     __hash_cached::value>;
+
+      using const_local_iterator = __detail::_Local_const_iterator<
+			key_type, _Value,
+			_ExtractKey, _Hash, _RangeHash, _Unused,
+			__constant_iterators::value, __hash_cached::value>;
+
+    private:
+      using __rehash_type = _RehashPolicy;
+      using __rehash_state = typename __rehash_type::_State;
+
+      using __unique_keys = typename __traits_type::__unique_keys;
+
+      using __hashtable_base = __detail::
+	_Hashtable_base<_Key, _Value, _ExtractKey,
+			_Equal, _Hash, _RangeHash, _Unused, _Traits>;
+
+      using __hash_code_base =  typename __hashtable_base::__hash_code_base;
+      using __hash_code =  typename __hashtable_base::__hash_code;
+      using __ireturn_type = typename __insert_base::__ireturn_type;
+
+      using __map_base = __detail::_Map_base<_Key, _Value, _Alloc, _ExtractKey,
+					     _Equal, _Hash, _RangeHash, _Unused,
+					     _RehashPolicy, _Traits>;
+
+      using __rehash_base = __detail::_Rehash_base<_Key, _Value, _Alloc,
+						   _ExtractKey, _Equal,
+						   _Hash, _RangeHash, _Unused,
+						   _RehashPolicy, _Traits>;
+
+      using __eq_base = __detail::_Equality<_Key, _Value, _Alloc, _ExtractKey,
+					    _Equal, _Hash, _RangeHash, _Unused,
+					    _RehashPolicy, _Traits>;
+
+      using __reuse_or_alloc_node_gen_t =
+	__detail::_ReuseOrAllocNode<__node_alloc_type>;
+      using __alloc_node_gen_t =
+	__detail::_AllocNode<__node_alloc_type>;
+      using __node_builder_t =
+	__detail::_NodeBuilder<_ExtractKey>;
+
+      // Simple RAII type for managing a node containing an element
+      struct _Scoped_node
+      {
+	// Take ownership of a node with a constructed element.
+	_Scoped_node(__node_ptr __n, __hashtable_alloc* __h)
+	: _M_h(__h), _M_node(__n) { }
+
+	// Allocate a node and construct an element within it.
+	template<typename... _Args>
+	  _Scoped_node(__hashtable_alloc* __h, _Args&&... __args)
+	  : _M_h(__h),
+	    _M_node(__h->_M_allocate_node(std::forward<_Args>(__args)...))
+	  { }
+
+	// Destroy element and deallocate node.
+	~_Scoped_node() { if (_M_node) _M_h->_M_deallocate_node(_M_node); };
+
+	_Scoped_node(const _Scoped_node&) = delete;
+	_Scoped_node& operator=(const _Scoped_node&) = delete;
+
+	__hashtable_alloc* _M_h;
+	__node_ptr _M_node;
+      };
+
+      template<typename _Ht>
+	static constexpr
+	__conditional_t<std::is_lvalue_reference<_Ht>::value,
+			const value_type&, value_type&&>
+	__fwd_value_for(value_type& __val) noexcept
+	{ return std::move(__val); }
+
+      // Compile-time diagnostics.
+
+      // _Hash_code_base has everything protected, so use this derived type to
+      // access it.
+      struct __hash_code_base_access : __hash_code_base
+      { using __hash_code_base::_M_bucket_index; };
+
+      // To get bucket index we need _RangeHash not to throw.
+      static_assert(is_nothrow_default_constructible<_RangeHash>::value,
+		    "Functor used to map hash code to bucket index"
+		    " must be nothrow default constructible");
+      static_assert(noexcept(
+	std::declval<const _RangeHash&>()((std::size_t)0, (std::size_t)0)),
+		    "Functor used to map hash code to bucket index must be"
+		    " noexcept");
+
+      // To compute bucket index we also need _ExtratKey not to throw.
+      static_assert(is_nothrow_default_constructible<_ExtractKey>::value,
+		    "_ExtractKey must be nothrow default constructible");
+      static_assert(noexcept(
+	std::declval<const _ExtractKey&>()(std::declval<_Value>())),
+		    "_ExtractKey functor must be noexcept invocable");
+
+      template<typename _Keya, typename _Valuea, typename _Alloca,
+	       typename _ExtractKeya, typename _Equala,
+	       typename _Hasha, typename _RangeHasha, typename _Unuseda,
+	       typename _RehashPolicya, typename _Traitsa,
+	       bool _Unique_keysa>
+	friend struct __detail::_Map_base;
+
+      template<typename _Keya, typename _Valuea, typename _Alloca,
+	       typename _ExtractKeya, typename _Equala,
+	       typename _Hasha, typename _RangeHasha, typename _Unuseda,
+	       typename _RehashPolicya, typename _Traitsa>
+	friend struct __detail::_Insert_base;
+
+      template<typename _Keya, typename _Valuea, typename _Alloca,
+	       typename _ExtractKeya, typename _Equala,
+	       typename _Hasha, typename _RangeHasha, typename _Unuseda,
+	       typename _RehashPolicya, typename _Traitsa,
+	       bool _Constant_iteratorsa>
+	friend struct __detail::_Insert;
+
+      template<typename _Keya, typename _Valuea, typename _Alloca,
+	       typename _ExtractKeya, typename _Equala,
+	       typename _Hasha, typename _RangeHasha, typename _Unuseda,
+	       typename _RehashPolicya, typename _Traitsa,
+	       bool _Unique_keysa>
+	friend struct __detail::_Equality;
+
+    public:
+      using size_type = typename __hashtable_base::size_type;
+      using difference_type = typename __hashtable_base::difference_type;
+
+#if __cplusplus > 201402L
+      using node_type = _Node_handle<_Key, _Value, __node_alloc_type>;
+      using insert_return_type = _Node_insert_return<iterator, node_type>;
+#endif
+
+    private:
+      __buckets_ptr		_M_buckets		= &_M_single_bucket;
+      size_type			_M_bucket_count		= 1;
+      __node_base		_M_before_begin;
+      size_type			_M_element_count	= 0;
+      _RehashPolicy		_M_rehash_policy;
+
+      // A single bucket used when only need for 1 bucket. Especially
+      // interesting in move semantic to leave hashtable with only 1 bucket
+      // which is not allocated so that we can have those operations noexcept
+      // qualified.
+      // Note that we can't leave hashtable with 0 bucket without adding
+      // numerous checks in the code to avoid 0 modulus.
+      __node_base_ptr		_M_single_bucket	= nullptr;
+
+      void
+      _M_update_bbegin()
+      {
+	if (_M_begin())
+	  _M_buckets[_M_bucket_index(*_M_begin())] = &_M_before_begin;
+      }
+
+      void
+      _M_update_bbegin(__node_ptr __n)
+      {
+	_M_before_begin._M_nxt = __n;
+	_M_update_bbegin();
+      }
+
+      bool
+      _M_uses_single_bucket(__buckets_ptr __bkts) const
+      { return __builtin_expect(__bkts == &_M_single_bucket, false); }
+
+      bool
+      _M_uses_single_bucket() const
+      { return _M_uses_single_bucket(_M_buckets); }
+
+      static constexpr size_t
+      __small_size_threshold() noexcept
+      {
+	return
+	  __detail::_Hashtable_hash_traits<_Hash>::__small_size_threshold();
+      }
+
+      __hashtable_alloc&
+      _M_base_alloc() { return *this; }
+
+      __buckets_ptr
+      _M_allocate_buckets(size_type __bkt_count)
+      {
+	if (__builtin_expect(__bkt_count == 1, false))
+	  {
+	    _M_single_bucket = nullptr;
+	    return &_M_single_bucket;
+	  }
+
+	return __hashtable_alloc::_M_allocate_buckets(__bkt_count);
+      }
+
+      void
+      _M_deallocate_buckets(__buckets_ptr __bkts, size_type __bkt_count)
+      {
+	if (_M_uses_single_bucket(__bkts))
+	  return;
+
+	__hashtable_alloc::_M_deallocate_buckets(__bkts, __bkt_count);
+      }
+
+      void
+      _M_deallocate_buckets()
+      { _M_deallocate_buckets(_M_buckets, _M_bucket_count); }
+
+      // Gets bucket begin, deals with the fact that non-empty buckets contain
+      // their before begin node.
+      __node_ptr
+      _M_bucket_begin(size_type __bkt) const;
+
+      __node_ptr
+      _M_begin() const
+      { return static_cast<__node_ptr>(_M_before_begin._M_nxt); }
+
+      // Assign *this using another _Hashtable instance. Whether elements
+      // are copied or moved depends on the _Ht reference.
+      template<typename _Ht>
+	void
+	_M_assign_elements(_Ht&&);
+
+      template<typename _Ht, typename _NodeGenerator>
+	void
+	_M_assign(_Ht&&, const _NodeGenerator&);
+
+      void
+      _M_move_assign(_Hashtable&&, true_type);
+
+      void
+      _M_move_assign(_Hashtable&&, false_type);
+
+      void
+      _M_reset() noexcept;
+
+      _Hashtable(const _Hash& __h, const _Equal& __eq,
+		 const allocator_type& __a)
+      : __hashtable_base(__h, __eq),
+	__hashtable_alloc(__node_alloc_type(__a)),
+	__enable_default_ctor(_Enable_default_constructor_tag{})
+      { }
+
+      template<bool _No_realloc = true>
+	static constexpr bool
+	_S_nothrow_move()
+	{
+#if __cplusplus <= 201402L
+	  return __and_<__bool_constant<_No_realloc>,
+			is_nothrow_copy_constructible<_Hash>,
+			is_nothrow_copy_constructible<_Equal>>::value;
+#else
+	  if constexpr (_No_realloc)
+	    if constexpr (is_nothrow_copy_constructible<_Hash>())
+	      return is_nothrow_copy_constructible<_Equal>();
+	  return false;
+#endif
+	}
+
+      _Hashtable(_Hashtable&& __ht, __node_alloc_type&& __a,
+		 true_type /* alloc always equal */)
+	noexcept(_S_nothrow_move());
+
+      _Hashtable(_Hashtable&&, __node_alloc_type&&,
+		 false_type /* alloc always equal */);
+
+      template<typename _InputIterator>
+	_Hashtable(_InputIterator __first, _InputIterator __last,
+		   size_type __bkt_count_hint,
+		   const _Hash&, const _Equal&, const allocator_type&,
+		   true_type __uks);
+
+      template<typename _InputIterator>
+	_Hashtable(_InputIterator __first, _InputIterator __last,
+		   size_type __bkt_count_hint,
+		   const _Hash&, const _Equal&, const allocator_type&,
+		   false_type __uks);
+
+    public:
+      // Constructor, destructor, assignment, swap
+      _Hashtable() = default;
+
+      _Hashtable(const _Hashtable&);
+
+      _Hashtable(const _Hashtable&, const allocator_type&);
+
+      explicit
+      _Hashtable(size_type __bkt_count_hint,
+		 const _Hash& __hf = _Hash(),
+		 const key_equal& __eql = key_equal(),
+		 const allocator_type& __a = allocator_type());
+
+      // Use delegating constructors.
+      _Hashtable(_Hashtable&& __ht)
+	noexcept(_S_nothrow_move())
+      : _Hashtable(std::move(__ht), std::move(__ht._M_node_allocator()),
+		   true_type{})
+      { }
+
+      _Hashtable(_Hashtable&& __ht, const allocator_type& __a)
+	noexcept(_S_nothrow_move<__node_alloc_traits::_S_always_equal()>())
+      : _Hashtable(std::move(__ht), __node_alloc_type(__a),
+		   typename __node_alloc_traits::is_always_equal{})
+      { }
+
+      explicit
+      _Hashtable(const allocator_type& __a)
+      : __hashtable_alloc(__node_alloc_type(__a)),
+	__enable_default_ctor(_Enable_default_constructor_tag{})
+      { }
+
+      template<typename _InputIterator>
+	_Hashtable(_InputIterator __f, _InputIterator __l,
+		   size_type __bkt_count_hint = 0,
+		   const _Hash& __hf = _Hash(),
+		   const key_equal& __eql = key_equal(),
+		   const allocator_type& __a = allocator_type())
+	: _Hashtable(__f, __l, __bkt_count_hint, __hf, __eql, __a,
+		     __unique_keys{})
+	{ }
+
+      _Hashtable(initializer_list<value_type> __l,
+		 size_type __bkt_count_hint = 0,
+		 const _Hash& __hf = _Hash(),
+		 const key_equal& __eql = key_equal(),
+		 const allocator_type& __a = allocator_type())
+      : _Hashtable(__l.begin(), __l.end(), __bkt_count_hint,
+		   __hf, __eql, __a, __unique_keys{})
+      { }
+
+      _Hashtable&
+      operator=(const _Hashtable& __ht);
+
+      _Hashtable&
+      operator=(_Hashtable&& __ht)
+      noexcept(__node_alloc_traits::_S_nothrow_move()
+	       && is_nothrow_move_assignable<_Hash>::value
+	       && is_nothrow_move_assignable<_Equal>::value)
+      {
+	constexpr bool __move_storage =
+	  __node_alloc_traits::_S_propagate_on_move_assign()
+	  || __node_alloc_traits::_S_always_equal();
+	_M_move_assign(std::move(__ht), __bool_constant<__move_storage>());
+	return *this;
+      }
+
+      _Hashtable&
+      operator=(initializer_list<value_type> __l)
+      {
+	__reuse_or_alloc_node_gen_t __roan(_M_begin(), *this);
+	_M_before_begin._M_nxt = nullptr;
+	clear();
+
+	// We consider that all elements of __l are going to be inserted.
+	auto __l_bkt_count = _M_rehash_policy._M_bkt_for_elements(__l.size());
+
+	// Do not shrink to keep potential user reservation.
+	if (_M_bucket_count < __l_bkt_count)
+	  rehash(__l_bkt_count);
+
+	this->_M_insert_range(__l.begin(), __l.end(), __roan, __unique_keys{});
+	return *this;
+      }
+
+      ~_Hashtable() noexcept;
+
+      void
+      swap(_Hashtable&)
+      noexcept(__and_<__is_nothrow_swappable<_Hash>,
+		      __is_nothrow_swappable<_Equal>>::value);
+
+      // Basic container operations
+      iterator
+      begin() noexcept
+      { return iterator(_M_begin()); }
+
+      const_iterator
+      begin() const noexcept
+      { return const_iterator(_M_begin()); }
+
+      iterator
+      end() noexcept
+      { return iterator(nullptr); }
+
+      const_iterator
+      end() const noexcept
+      { return const_iterator(nullptr); }
+
+      const_iterator
+      cbegin() const noexcept
+      { return const_iterator(_M_begin()); }
+
+      const_iterator
+      cend() const noexcept
+      { return const_iterator(nullptr); }
+
+      size_type
+      size() const noexcept
+      { return _M_element_count; }
+
+      _GLIBCXX_NODISCARD bool
+      empty() const noexcept
+      { return size() == 0; }
+
+      allocator_type
+      get_allocator() const noexcept
+      { return allocator_type(this->_M_node_allocator()); }
+
+      size_type
+      max_size() const noexcept
+      { return __node_alloc_traits::max_size(this->_M_node_allocator()); }
+
+      // Observers
+      key_equal
+      key_eq() const
+      { return this->_M_eq(); }
+
+      // hash_function, if present, comes from _Hash_code_base.
+
+      // Bucket operations
+      size_type
+      bucket_count() const noexcept
+      { return _M_bucket_count; }
+
+      size_type
+      max_bucket_count() const noexcept
+      { return max_size(); }
+
+      size_type
+      bucket_size(size_type __bkt) const
+      { return std::distance(begin(__bkt), end(__bkt)); }
+
+      size_type
+      bucket(const key_type& __k) const
+      { return _M_bucket_index(this->_M_hash_code(__k)); }
+
+      local_iterator
+      begin(size_type __bkt)
+      {
+	return local_iterator(*this, _M_bucket_begin(__bkt),
+			      __bkt, _M_bucket_count);
+      }
+
+      local_iterator
+      end(size_type __bkt)
+      { return local_iterator(*this, nullptr, __bkt, _M_bucket_count); }
+
+      const_local_iterator
+      begin(size_type __bkt) const
+      {
+	return const_local_iterator(*this, _M_bucket_begin(__bkt),
+				    __bkt, _M_bucket_count);
+      }
+
+      const_local_iterator
+      end(size_type __bkt) const
+      { return const_local_iterator(*this, nullptr, __bkt, _M_bucket_count); }
+
+      // DR 691.
+      const_local_iterator
+      cbegin(size_type __bkt) const
+      {
+	return const_local_iterator(*this, _M_bucket_begin(__bkt),
+				    __bkt, _M_bucket_count);
+      }
+
+      const_local_iterator
+      cend(size_type __bkt) const
+      { return const_local_iterator(*this, nullptr, __bkt, _M_bucket_count); }
+
+      float
+      load_factor() const noexcept
+      {
+	return static_cast<float>(size()) / static_cast<float>(bucket_count());
+      }
+
+      // max_load_factor, if present, comes from _Rehash_base.
+
+      // Generalization of max_load_factor.  Extension, not found in
+      // TR1.  Only useful if _RehashPolicy is something other than
+      // the default.
+      const _RehashPolicy&
+      __rehash_policy() const
+      { return _M_rehash_policy; }
+
+      void
+      __rehash_policy(const _RehashPolicy& __pol)
+      { _M_rehash_policy = __pol; }
+
+      // Lookup.
+      iterator
+      find(const key_type& __k);
+
+      const_iterator
+      find(const key_type& __k) const;
+
+      size_type
+      count(const key_type& __k) const;
+
+      std::pair<iterator, iterator>
+      equal_range(const key_type& __k);
+
+      std::pair<const_iterator, const_iterator>
+      equal_range(const key_type& __k) const;
+
+#if __cplusplus >= 202002L
+#define __cpp_lib_generic_unordered_lookup 201811L
+
+      template<typename _Kt,
+	       typename = __has_is_transparent_t<_Hash, _Kt>,
+	       typename = __has_is_transparent_t<_Equal, _Kt>>
+	iterator
+	_M_find_tr(const _Kt& __k);
+
+      template<typename _Kt,
+	       typename = __has_is_transparent_t<_Hash, _Kt>,
+	       typename = __has_is_transparent_t<_Equal, _Kt>>
+	const_iterator
+	_M_find_tr(const _Kt& __k) const;
+
+      template<typename _Kt,
+	       typename = __has_is_transparent_t<_Hash, _Kt>,
+	       typename = __has_is_transparent_t<_Equal, _Kt>>
+	size_type
+	_M_count_tr(const _Kt& __k) const;
+
+      template<typename _Kt,
+	       typename = __has_is_transparent_t<_Hash, _Kt>,
+	       typename = __has_is_transparent_t<_Equal, _Kt>>
+	pair<iterator, iterator>
+	_M_equal_range_tr(const _Kt& __k);
+
+      template<typename _Kt,
+	       typename = __has_is_transparent_t<_Hash, _Kt>,
+	       typename = __has_is_transparent_t<_Equal, _Kt>>
+	pair<const_iterator, const_iterator>
+	_M_equal_range_tr(const _Kt& __k) const;
+#endif // C++20
+
+    private:
+      // Bucket index computation helpers.
+      size_type
+      _M_bucket_index(const __node_value_type& __n) const noexcept
+      { return __hash_code_base::_M_bucket_index(__n, _M_bucket_count); }
+
+      size_type
+      _M_bucket_index(__hash_code __c) const
+      { return __hash_code_base::_M_bucket_index(__c, _M_bucket_count); }
+
+      __node_base_ptr
+      _M_find_before_node(const key_type&);
+
+      // Find and insert helper functions and types
+      // Find the node before the one matching the criteria.
+      __node_base_ptr
+      _M_find_before_node(size_type, const key_type&, __hash_code) const;
+
+      template<typename _Kt>
+	__node_base_ptr
+	_M_find_before_node_tr(size_type, const _Kt&, __hash_code) const;
+
+      __node_ptr
+      _M_find_node(size_type __bkt, const key_type& __key,
+		   __hash_code __c) const
+      {
+	__node_base_ptr __before_n = _M_find_before_node(__bkt, __key, __c);
+	if (__before_n)
+	  return static_cast<__node_ptr>(__before_n->_M_nxt);
+	return nullptr;
+      }
+
+      template<typename _Kt>
+	__node_ptr
+	_M_find_node_tr(size_type __bkt, const _Kt& __key,
+			__hash_code __c) const
+	{
+	  auto __before_n = _M_find_before_node_tr(__bkt, __key, __c);
+	  if (__before_n)
+	    return static_cast<__node_ptr>(__before_n->_M_nxt);
+	  return nullptr;
+	}
+
+      // Insert a node at the beginning of a bucket.
+      void
+      _M_insert_bucket_begin(size_type, __node_ptr);
+
+      // Remove the bucket first node
+      void
+      _M_remove_bucket_begin(size_type __bkt, __node_ptr __next_n,
+			     size_type __next_bkt);
+
+      // Get the node before __n in the bucket __bkt
+      __node_base_ptr
+      _M_get_previous_node(size_type __bkt, __node_ptr __n);
+
+      pair<const_iterator, __hash_code>
+      _M_compute_hash_code(const_iterator __hint, const key_type& __k) const;
+
+      // Insert node __n with hash code __code, in bucket __bkt if no
+      // rehash (assumes no element with same key already present).
+      // Takes ownership of __n if insertion succeeds, throws otherwise.
+      iterator
+      _M_insert_unique_node(size_type __bkt, __hash_code,
+			    __node_ptr __n, size_type __n_elt = 1);
+
+      // Insert node __n with key __k and hash code __code.
+      // Takes ownership of __n if insertion succeeds, throws otherwise.
+      iterator
+      _M_insert_multi_node(__node_ptr __hint,
+			   __hash_code __code, __node_ptr __n);
+
+      template<typename... _Args>
+	std::pair<iterator, bool>
+	_M_emplace(true_type __uks, _Args&&... __args);
+
+      template<typename... _Args>
+	iterator
+	_M_emplace(false_type __uks, _Args&&... __args)
+	{ return _M_emplace(cend(), __uks, std::forward<_Args>(__args)...); }
+
+      // Emplace with hint, useless when keys are unique.
+      template<typename... _Args>
+	iterator
+	_M_emplace(const_iterator, true_type __uks, _Args&&... __args)
+	{ return _M_emplace(__uks, std::forward<_Args>(__args)...).first; }
+
+      template<typename... _Args>
+	iterator
+	_M_emplace(const_iterator, false_type __uks, _Args&&... __args);
+
+      template<typename _Kt, typename _Arg, typename _NodeGenerator>
+	std::pair<iterator, bool>
+	_M_insert_unique(_Kt&&, _Arg&&, const _NodeGenerator&);
+
+      template<typename _Kt>
+	static __conditional_t<
+	  __and_<__is_nothrow_invocable<_Hash&, const key_type&>,
+		 __not_<__is_nothrow_invocable<_Hash&, _Kt>>>::value,
+	  key_type, _Kt&&>
+	_S_forward_key(_Kt&& __k)
+	{ return std::forward<_Kt>(__k); }
+
+      static const key_type&
+      _S_forward_key(const key_type& __k)
+      { return __k; }
+
+      static key_type&&
+      _S_forward_key(key_type&& __k)
+      { return std::move(__k); }
+
+      template<typename _Arg, typename _NodeGenerator>
+	std::pair<iterator, bool>
+	_M_insert(_Arg&& __arg, const _NodeGenerator& __node_gen,
+		  true_type /* __uks */)
+	{
+	  return _M_insert_unique(
+	    _S_forward_key(_ExtractKey{}(std::forward<_Arg>(__arg))),
+	    std::forward<_Arg>(__arg), __node_gen);
+	}
+
+      template<typename _Arg, typename _NodeGenerator>
+	iterator
+	_M_insert(_Arg&& __arg, const _NodeGenerator& __node_gen,
+		  false_type __uks)
+	{
+	  return _M_insert(cend(), std::forward<_Arg>(__arg), __node_gen,
+			   __uks);
+	}
+
+      // Insert with hint, not used when keys are unique.
+      template<typename _Arg, typename _NodeGenerator>
+	iterator
+	_M_insert(const_iterator, _Arg&& __arg,
+		  const _NodeGenerator& __node_gen, true_type __uks)
+	{
+	  return
+	    _M_insert(std::forward<_Arg>(__arg), __node_gen, __uks).first;
+	}
+
+      // Insert with hint when keys are not unique.
+      template<typename _Arg, typename _NodeGenerator>
+	iterator
+	_M_insert(const_iterator, _Arg&&,
+		  const _NodeGenerator&, false_type __uks);
+
+      size_type
+      _M_erase(true_type __uks, const key_type&);
+
+      size_type
+      _M_erase(false_type __uks, const key_type&);
+
+      iterator
+      _M_erase(size_type __bkt, __node_base_ptr __prev_n, __node_ptr __n);
+
+    public:
+      // Emplace
+      template<typename... _Args>
+	__ireturn_type
+	emplace(_Args&&... __args)
+	{ return _M_emplace(__unique_keys{}, std::forward<_Args>(__args)...); }
+
+      template<typename... _Args>
+	iterator
+	emplace_hint(const_iterator __hint, _Args&&... __args)
+	{
+	  return _M_emplace(__hint, __unique_keys{},
+			    std::forward<_Args>(__args)...);
+	}
+
+      // Insert member functions via inheritance.
+
+      // Erase
+      iterator
+      erase(const_iterator);
+
+      // LWG 2059.
+      iterator
+      erase(iterator __it)
+      { return erase(const_iterator(__it)); }
+
+      size_type
+      erase(const key_type& __k)
+      { return _M_erase(__unique_keys{}, __k); }
+
+      iterator
+      erase(const_iterator, const_iterator);
+
+      void
+      clear() noexcept;
+
+      // Set number of buckets keeping it appropriate for container's number
+      // of elements.
+      void rehash(size_type __bkt_count);
+
+      // DR 1189.
+      // reserve, if present, comes from _Rehash_base.
+
+#if __cplusplus > 201402L
+      /// Re-insert an extracted node into a container with unique keys.
+      insert_return_type
+      _M_reinsert_node(node_type&& __nh)
+      {
+	insert_return_type __ret;
+	if (__nh.empty())
+	  __ret.position = end();
+	else
+	  {
+	    __glibcxx_assert(get_allocator() == __nh.get_allocator());
+
+	    const key_type& __k = __nh._M_key();
+	    __hash_code __code = this->_M_hash_code(__k);
+	    size_type __bkt = _M_bucket_index(__code);
+	    if (__node_ptr __n = _M_find_node(__bkt, __k, __code))
+	      {
+		__ret.node = std::move(__nh);
+		__ret.position = iterator(__n);
+		__ret.inserted = false;
+	      }
+	    else
+	      {
+		__ret.position
+		  = _M_insert_unique_node(__bkt, __code, __nh._M_ptr);
+		__nh._M_ptr = nullptr;
+		__ret.inserted = true;
+	      }
+	  }
+	return __ret;
+      }
+
+      /// Re-insert an extracted node into a container with equivalent keys.
+      iterator
+      _M_reinsert_node_multi(const_iterator __hint, node_type&& __nh)
+      {
+	if (__nh.empty())
+	  return end();
+
+	__glibcxx_assert(get_allocator() == __nh.get_allocator());
+
+	const key_type& __k = __nh._M_key();
+	auto __code = this->_M_hash_code(__k);
+	auto __ret
+	  = _M_insert_multi_node(__hint._M_cur, __code, __nh._M_ptr);
+	__nh._M_ptr = nullptr;
+	return __ret;
+      }
+
+    private:
+      node_type
+      _M_extract_node(size_t __bkt, __node_base_ptr __prev_n)
+      {
+	__node_ptr __n = static_cast<__node_ptr>(__prev_n->_M_nxt);
+	if (__prev_n == _M_buckets[__bkt])
+	  _M_remove_bucket_begin(__bkt, __n->_M_next(),
+	     __n->_M_nxt ? _M_bucket_index(*__n->_M_next()) : 0);
+	else if (__n->_M_nxt)
+	  {
+	    size_type __next_bkt = _M_bucket_index(*__n->_M_next());
+	    if (__next_bkt != __bkt)
+	      _M_buckets[__next_bkt] = __prev_n;
+	  }
+
+	__prev_n->_M_nxt = __n->_M_nxt;
+	__n->_M_nxt = nullptr;
+	--_M_element_count;
+	return { __n, this->_M_node_allocator() };
+      }
+
+    public:
+      // Extract a node.
+      node_type
+      extract(const_iterator __pos)
+      {
+	size_t __bkt = _M_bucket_index(*__pos._M_cur);
+	return _M_extract_node(__bkt,
+			       _M_get_previous_node(__bkt, __pos._M_cur));
+      }
+
+      /// Extract a node.
+      node_type
+      extract(const _Key& __k)
+      {
+	node_type __nh;
+	__hash_code __code = this->_M_hash_code(__k);
+	std::size_t __bkt = _M_bucket_index(__code);
+	if (__node_base_ptr __prev_node = _M_find_before_node(__bkt, __k, __code))
+	  __nh = _M_extract_node(__bkt, __prev_node);
+	return __nh;
+      }
+
+      /// Merge from a compatible container into one with unique keys.
+      template<typename _Compatible_Hashtable>
+	void
+	_M_merge_unique(_Compatible_Hashtable& __src)
+	{
+	  static_assert(is_same_v<typename _Compatible_Hashtable::node_type,
+	      node_type>, "Node types are compatible");
+	  __glibcxx_assert(get_allocator() == __src.get_allocator());
+
+	  auto __n_elt = __src.size();
+	  for (auto __i = __src.cbegin(), __end = __src.cend(); __i != __end;)
+	    {
+	      auto __pos = __i++;
+	      const key_type& __k = _ExtractKey{}(*__pos);
+	      __hash_code __code
+		= this->_M_hash_code(__src.hash_function(), *__pos._M_cur);
+	      size_type __bkt = _M_bucket_index(__code);
+	      if (_M_find_node(__bkt, __k, __code) == nullptr)
+		{
+		  auto __nh = __src.extract(__pos);
+		  _M_insert_unique_node(__bkt, __code, __nh._M_ptr, __n_elt);
+		  __nh._M_ptr = nullptr;
+		  __n_elt = 1;
+		}
+	      else if (__n_elt != 1)
+		--__n_elt;
+	    }
+	}
+
+      /// Merge from a compatible container into one with equivalent keys.
+      template<typename _Compatible_Hashtable>
+	void
+	_M_merge_multi(_Compatible_Hashtable& __src)
+	{
+	  static_assert(is_same_v<typename _Compatible_Hashtable::node_type,
+	      node_type>, "Node types are compatible");
+	  __glibcxx_assert(get_allocator() == __src.get_allocator());
+
+	  __node_ptr __hint = nullptr;
+	  this->reserve(size() + __src.size());
+	  for (auto __i = __src.cbegin(), __end = __src.cend(); __i != __end;)
+	    {
+	      auto __pos = __i++;
+	      __hash_code __code
+		= this->_M_hash_code(__src.hash_function(), *__pos._M_cur);
+	      auto __nh = __src.extract(__pos);
+	      __hint = _M_insert_multi_node(__hint, __code, __nh._M_ptr)._M_cur;
+	      __nh._M_ptr = nullptr;
+	    }
+	}
+#endif // C++17
+
+    private:
+      // Helper rehash method used when keys are unique.
+      void _M_rehash_aux(size_type __bkt_count, true_type __uks);
+
+      // Helper rehash method used when keys can be non-unique.
+      void _M_rehash_aux(size_type __bkt_count, false_type __uks);
+
+      // Unconditionally change size of bucket array to n, restore
+      // hash policy state to __state on exception.
+      void _M_rehash(size_type __bkt_count, const __rehash_state& __state);
+    };
+
+  // Definitions of class template _Hashtable's out-of-line member functions.
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    auto
+    _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+	       _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
+    _M_bucket_begin(size_type __bkt) const
+    -> __node_ptr
+    {
+      __node_base_ptr __n = _M_buckets[__bkt];
+      return __n ? static_cast<__node_ptr>(__n->_M_nxt) : nullptr;
+    }
+
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+	       _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
+    _Hashtable(size_type __bkt_count_hint,
+	       const _Hash& __h, const _Equal& __eq, const allocator_type& __a)
+    : _Hashtable(__h, __eq, __a)
+    {
+      auto __bkt_count = _M_rehash_policy._M_next_bkt(__bkt_count_hint);
+      if (__bkt_count > _M_bucket_count)
+	{
+	  _M_buckets = _M_allocate_buckets(__bkt_count);
+	  _M_bucket_count = __bkt_count;
+	}
+    }
+
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    template<typename _InputIterator>
+      _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+		 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
+      _Hashtable(_InputIterator __f, _InputIterator __l,
+		 size_type __bkt_count_hint,
+		 const _Hash& __h, const _Equal& __eq,
+		 const allocator_type& __a, true_type /* __uks */)
+      : _Hashtable(__bkt_count_hint, __h, __eq, __a)
+      {
+	for (; __f != __l; ++__f)
+	  this->insert(*__f);
+      }
+
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    template<typename _InputIterator>
+      _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+		 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
+      _Hashtable(_InputIterator __f, _InputIterator __l,
+		 size_type __bkt_count_hint,
+		 const _Hash& __h, const _Equal& __eq,
+		 const allocator_type& __a, false_type /* __uks */)
+      : _Hashtable(__h, __eq, __a)
+      {
+	auto __nb_elems = __detail::__distance_fw(__f, __l);
+	auto __bkt_count =
+	  _M_rehash_policy._M_next_bkt(
+	    std::max(_M_rehash_policy._M_bkt_for_elements(__nb_elems),
+		     __bkt_count_hint));
+
+	if (__bkt_count > _M_bucket_count)
+	  {
+	    _M_buckets = _M_allocate_buckets(__bkt_count);
+	    _M_bucket_count = __bkt_count;
+	  }
+
+	for (; __f != __l; ++__f)
+	  this->insert(*__f);
+      }
+
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    auto
+    _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+	       _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
+    operator=(const _Hashtable& __ht)
+    -> _Hashtable&
+    {
+      if (&__ht == this)
+	return *this;
+
+      if (__node_alloc_traits::_S_propagate_on_copy_assign())
+	{
+	  auto& __this_alloc = this->_M_node_allocator();
+	  auto& __that_alloc = __ht._M_node_allocator();
+	  if (!__node_alloc_traits::_S_always_equal()
+	      && __this_alloc != __that_alloc)
+	    {
+	      // Replacement allocator cannot free existing storage.
+	      this->_M_deallocate_nodes(_M_begin());
+	      _M_before_begin._M_nxt = nullptr;
+	      _M_deallocate_buckets();
+	      _M_buckets = nullptr;
+	      std::__alloc_on_copy(__this_alloc, __that_alloc);
+	      __hashtable_base::operator=(__ht);
+	      _M_bucket_count = __ht._M_bucket_count;
+	      _M_element_count = __ht._M_element_count;
+	      _M_rehash_policy = __ht._M_rehash_policy;
+	      __alloc_node_gen_t __alloc_node_gen(*this);
+	      __try
+		{
+		  _M_assign(__ht, __alloc_node_gen);
+		}
+	      __catch(...)
+		{
+		  // _M_assign took care of deallocating all memory. Now we
+		  // must make sure this instance remains in a usable state.
+		  _M_reset();
+		  __throw_exception_again;
+		}
+	      return *this;
+	    }
+	  std::__alloc_on_copy(__this_alloc, __that_alloc);
+	}
+
+      // Reuse allocated buckets and nodes.
+      _M_assign_elements(__ht);
+      return *this;
+    }
+
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    template<typename _Ht>
+      void
+      _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+		 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
+      _M_assign_elements(_Ht&& __ht)
+      {
+	__buckets_ptr __former_buckets = nullptr;
+	std::size_t __former_bucket_count = _M_bucket_count;
+	const __rehash_state& __former_state = _M_rehash_policy._M_state();
+
+	if (_M_bucket_count != __ht._M_bucket_count)
+	  {
+	    __former_buckets = _M_buckets;
+	    _M_buckets = _M_allocate_buckets(__ht._M_bucket_count);
+	    _M_bucket_count = __ht._M_bucket_count;
+	  }
+	else
+	  __builtin_memset(_M_buckets, 0,
+			   _M_bucket_count * sizeof(__node_base_ptr));
+
+	__try
+	  {
+	    __hashtable_base::operator=(std::forward<_Ht>(__ht));
+	    _M_element_count = __ht._M_element_count;
+	    _M_rehash_policy = __ht._M_rehash_policy;
+	    __reuse_or_alloc_node_gen_t __roan(_M_begin(), *this);
+	    _M_before_begin._M_nxt = nullptr;
+	    _M_assign(std::forward<_Ht>(__ht), __roan);
+	    if (__former_buckets)
+	      _M_deallocate_buckets(__former_buckets, __former_bucket_count);
+	  }
+	__catch(...)
+	  {
+	    if (__former_buckets)
+	      {
+		// Restore previous buckets.
+		_M_deallocate_buckets();
+		_M_rehash_policy._M_reset(__former_state);
+		_M_buckets = __former_buckets;
+		_M_bucket_count = __former_bucket_count;
+	      }
+	    __builtin_memset(_M_buckets, 0,
+			     _M_bucket_count * sizeof(__node_base_ptr));
+	    __throw_exception_again;
+	  }
+      }
+
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    template<typename _Ht, typename _NodeGenerator>
+      void
+      _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+		 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
+      _M_assign(_Ht&& __ht, const _NodeGenerator& __node_gen)
+      {
+	__buckets_ptr __buckets = nullptr;
+	if (!_M_buckets)
+	  _M_buckets = __buckets = _M_allocate_buckets(_M_bucket_count);
+
+	__try
+	  {
+	    if (!__ht._M_before_begin._M_nxt)
+	      return;
+
+	    // First deal with the special first node pointed to by
+	    // _M_before_begin.
+	    __node_ptr __ht_n = __ht._M_begin();
+	    __node_ptr __this_n
+	      = __node_gen(__fwd_value_for<_Ht>(__ht_n->_M_v()));
+	    this->_M_copy_code(*__this_n, *__ht_n);
+	    _M_update_bbegin(__this_n);
+
+	    // Then deal with other nodes.
+	    __node_ptr __prev_n = __this_n;
+	    for (__ht_n = __ht_n->_M_next(); __ht_n; __ht_n = __ht_n->_M_next())
+	      {
+		__this_n = __node_gen(__fwd_value_for<_Ht>(__ht_n->_M_v()));
+		__prev_n->_M_nxt = __this_n;
+		this->_M_copy_code(*__this_n, *__ht_n);
+		size_type __bkt = _M_bucket_index(*__this_n);
+		if (!_M_buckets[__bkt])
+		  _M_buckets[__bkt] = __prev_n;
+		__prev_n = __this_n;
+	      }
+	  }
+	__catch(...)
+	  {
+	    clear();
+	    if (__buckets)
+	      _M_deallocate_buckets();
+	    __throw_exception_again;
+	  }
+      }
+
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    void
+    _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+	       _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
+    _M_reset() noexcept
+    {
+      _M_rehash_policy._M_reset();
+      _M_bucket_count = 1;
+      _M_single_bucket = nullptr;
+      _M_buckets = &_M_single_bucket;
+      _M_before_begin._M_nxt = nullptr;
+      _M_element_count = 0;
+    }
+
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    void
+    _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+	       _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
+    _M_move_assign(_Hashtable&& __ht, true_type)
+    {
+      if (__builtin_expect(std::__addressof(__ht) == this, false))
+	return;
+
+      this->_M_deallocate_nodes(_M_begin());
+      _M_deallocate_buckets();
+      __hashtable_base::operator=(std::move(__ht));
+      _M_rehash_policy = __ht._M_rehash_policy;
+      if (!__ht._M_uses_single_bucket())
+	_M_buckets = __ht._M_buckets;
+      else
+	{
+	  _M_buckets = &_M_single_bucket;
+	  _M_single_bucket = __ht._M_single_bucket;
+	}
+
+      _M_bucket_count = __ht._M_bucket_count;
+      _M_before_begin._M_nxt = __ht._M_before_begin._M_nxt;
+      _M_element_count = __ht._M_element_count;
+      std::__alloc_on_move(this->_M_node_allocator(), __ht._M_node_allocator());
+
+      // Fix bucket containing the _M_before_begin pointer that can't be moved.
+      _M_update_bbegin();
+      __ht._M_reset();
+    }
+
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    void
+    _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+	       _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
+    _M_move_assign(_Hashtable&& __ht, false_type)
+    {
+      if (__ht._M_node_allocator() == this->_M_node_allocator())
+	_M_move_assign(std::move(__ht), true_type{});
+      else
+	{
+	  // Can't move memory, move elements then.
+	  _M_assign_elements(std::move(__ht));
+	  __ht.clear();
+	}
+    }
+
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+	       _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
+    _Hashtable(const _Hashtable& __ht)
+    : __hashtable_base(__ht),
+      __map_base(__ht),
+      __rehash_base(__ht),
+      __hashtable_alloc(
+	__node_alloc_traits::_S_select_on_copy(__ht._M_node_allocator())),
+      __enable_default_ctor(__ht),
+      _M_buckets(nullptr),
+      _M_bucket_count(__ht._M_bucket_count),
+      _M_element_count(__ht._M_element_count),
+      _M_rehash_policy(__ht._M_rehash_policy)
+    {
+      __alloc_node_gen_t __alloc_node_gen(*this);
+      _M_assign(__ht, __alloc_node_gen);
+    }
+
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+	       _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
+    _Hashtable(_Hashtable&& __ht, __node_alloc_type&& __a,
+	       true_type /* alloc always equal */)
+    noexcept(_S_nothrow_move())
+    : __hashtable_base(__ht),
+      __map_base(__ht),
+      __rehash_base(__ht),
+      __hashtable_alloc(std::move(__a)),
+      __enable_default_ctor(__ht),
+      _M_buckets(__ht._M_buckets),
+      _M_bucket_count(__ht._M_bucket_count),
+      _M_before_begin(__ht._M_before_begin._M_nxt),
+      _M_element_count(__ht._M_element_count),
+      _M_rehash_policy(__ht._M_rehash_policy)
+    {
+      // Update buckets if __ht is using its single bucket.
+      if (__ht._M_uses_single_bucket())
+	{
+	  _M_buckets = &_M_single_bucket;
+	  _M_single_bucket = __ht._M_single_bucket;
+	}
+
+      // Fix bucket containing the _M_before_begin pointer that can't be moved.
+      _M_update_bbegin();
+
+      __ht._M_reset();
+    }
+
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+	       _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
+    _Hashtable(const _Hashtable& __ht, const allocator_type& __a)
+    : __hashtable_base(__ht),
+      __map_base(__ht),
+      __rehash_base(__ht),
+      __hashtable_alloc(__node_alloc_type(__a)),
+      __enable_default_ctor(__ht),
+      _M_buckets(),
+      _M_bucket_count(__ht._M_bucket_count),
+      _M_element_count(__ht._M_element_count),
+      _M_rehash_policy(__ht._M_rehash_policy)
+    {
+      __alloc_node_gen_t __alloc_node_gen(*this);
+      _M_assign(__ht, __alloc_node_gen);
+    }
+
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+	       _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
+    _Hashtable(_Hashtable&& __ht, __node_alloc_type&& __a,
+	       false_type /* alloc always equal */)
+    : __hashtable_base(__ht),
+      __map_base(__ht),
+      __rehash_base(__ht),
+      __hashtable_alloc(std::move(__a)),
+      __enable_default_ctor(__ht),
+      _M_buckets(nullptr),
+      _M_bucket_count(__ht._M_bucket_count),
+      _M_element_count(__ht._M_element_count),
+      _M_rehash_policy(__ht._M_rehash_policy)
+    {
+      if (__ht._M_node_allocator() == this->_M_node_allocator())
+	{
+	  if (__ht._M_uses_single_bucket())
+	    {
+	      _M_buckets = &_M_single_bucket;
+	      _M_single_bucket = __ht._M_single_bucket;
+	    }
+	  else
+	    _M_buckets = __ht._M_buckets;
+
+	  // Fix bucket containing the _M_before_begin pointer that can't be
+	  // moved.
+	  _M_update_bbegin(__ht._M_begin());
+
+	  __ht._M_reset();
+	}
+      else
+	{
+	  __alloc_node_gen_t __alloc_gen(*this);
+
+	  using _Fwd_Ht = __conditional_t<
+	    __move_if_noexcept_cond<value_type>::value,
+	    const _Hashtable&, _Hashtable&&>;
+	  _M_assign(std::forward<_Fwd_Ht>(__ht), __alloc_gen);
+	  __ht.clear();
+	}
+    }
+
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+	       _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
+    ~_Hashtable() noexcept
+    {
+      // Getting a bucket index from a node shall not throw because it is used
+      // in methods (erase, swap...) that shall not throw. Need a complete
+      // type to check this, so do it in the destructor not at class scope.
+      static_assert(noexcept(declval<const __hash_code_base_access&>()
+			._M_bucket_index(declval<const __node_value_type&>(),
+					 (std::size_t)0)),
+		    "Cache the hash code or qualify your functors involved"
+		    " in hash code and bucket index computation with noexcept");
+
+      clear();
+      _M_deallocate_buckets();
+    }
+
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    void
+    _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+	       _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
+    swap(_Hashtable& __x)
+    noexcept(__and_<__is_nothrow_swappable<_Hash>,
+			__is_nothrow_swappable<_Equal>>::value)
+    {
+      // The only base class with member variables is hash_code_base.
+      // We define _Hash_code_base::_M_swap because different
+      // specializations have different members.
+      this->_M_swap(__x);
+
+      std::__alloc_on_swap(this->_M_node_allocator(), __x._M_node_allocator());
+      std::swap(_M_rehash_policy, __x._M_rehash_policy);
+
+      // Deal properly with potentially moved instances.
+      if (this->_M_uses_single_bucket())
+	{
+	  if (!__x._M_uses_single_bucket())
+	    {
+	      _M_buckets = __x._M_buckets;
+	      __x._M_buckets = &__x._M_single_bucket;
+	    }
+	}
+      else if (__x._M_uses_single_bucket())
+	{
+	  __x._M_buckets = _M_buckets;
+	  _M_buckets = &_M_single_bucket;
+	}	
+      else
+	std::swap(_M_buckets, __x._M_buckets);
+
+      std::swap(_M_bucket_count, __x._M_bucket_count);
+      std::swap(_M_before_begin._M_nxt, __x._M_before_begin._M_nxt);
+      std::swap(_M_element_count, __x._M_element_count);
+      std::swap(_M_single_bucket, __x._M_single_bucket);
+
+      // Fix buckets containing the _M_before_begin pointers that can't be
+      // swapped.
+      _M_update_bbegin();
+      __x._M_update_bbegin();
+    }
+
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    auto
+    _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+	       _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
+    find(const key_type& __k)
+    -> iterator
+    {
+      if (size() <= __small_size_threshold())
+	{
+	  for (auto __it = begin(); __it != end(); ++__it)
+	    if (this->_M_key_equals(__k, *__it._M_cur))
+	      return __it;
+	  return end();
+	}
+
+      __hash_code __code = this->_M_hash_code(__k);
+      std::size_t __bkt = _M_bucket_index(__code);
+      return iterator(_M_find_node(__bkt, __k, __code));
+    }
+
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    auto
+    _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+	       _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
+    find(const key_type& __k) const
+    -> const_iterator
+    {
+      if (size() <= __small_size_threshold())
+	{
+	  for (auto __it = begin(); __it != end(); ++__it)
+	    if (this->_M_key_equals(__k, *__it._M_cur))
+	      return __it;
+	  return end();
+	}
+
+      __hash_code __code = this->_M_hash_code(__k);
+      std::size_t __bkt = _M_bucket_index(__code);
+      return const_iterator(_M_find_node(__bkt, __k, __code));
+    }
+
+#if __cplusplus > 201703L
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    template<typename _Kt, typename, typename>
+      auto
+      _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+		 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
+      _M_find_tr(const _Kt& __k)
+      -> iterator
+      {
+	__hash_code __code = this->_M_hash_code_tr(__k);
+	std::size_t __bkt = _M_bucket_index(__code);
+	return iterator(_M_find_node_tr(__bkt, __k, __code));
+      }
+
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    template<typename _Kt, typename, typename>
+      auto
+      _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+		 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
+      _M_find_tr(const _Kt& __k) const
+      -> const_iterator
+      {
+	__hash_code __code = this->_M_hash_code_tr(__k);
+	std::size_t __bkt = _M_bucket_index(__code);
+	return const_iterator(_M_find_node_tr(__bkt, __k, __code));
+      }
+#endif
+
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    auto
+    _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+	       _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
+    count(const key_type& __k) const
+    -> size_type
+    {
+      auto __it = find(__k);
+      if (!__it._M_cur)
+	return 0;
+
+      if (__unique_keys::value)
+	return 1;
+
+      // All equivalent values are next to each other, if we find a
+      // non-equivalent value after an equivalent one it means that we won't
+      // find any new equivalent value.
+      size_type __result = 1;
+      for (auto __ref = __it++;
+	   __it._M_cur && this->_M_node_equals(*__ref._M_cur, *__it._M_cur);
+	   ++__it)
+	++__result;
+
+      return __result;
+    }
+
+#if __cplusplus > 201703L
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    template<typename _Kt, typename, typename>
+      auto
+      _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+		 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
+      _M_count_tr(const _Kt& __k) const
+      -> size_type
+      {
+	__hash_code __code = this->_M_hash_code_tr(__k);
+	std::size_t __bkt = _M_bucket_index(__code);
+	auto __n = _M_find_node_tr(__bkt, __k, __code);
+	if (!__n)
+	  return 0;
+
+	// All equivalent values are next to each other, if we find a
+	// non-equivalent value after an equivalent one it means that we won't
+	// find any new equivalent value.
+	iterator __it(__n);
+	size_type __result = 1;
+	for (++__it;
+	     __it._M_cur && this->_M_equals_tr(__k, __code, *__it._M_cur);
+	     ++__it)
+	  ++__result;
+
+	return __result;
+      }
+#endif
+
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    auto
+    _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+	       _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
+    equal_range(const key_type& __k)
+    -> pair<iterator, iterator>
+    {
+      auto __ite = find(__k);
+      if (!__ite._M_cur)
+	return { __ite, __ite };
+
+      auto __beg = __ite++;
+      if (__unique_keys::value)
+	return { __beg, __ite };
+
+      // All equivalent values are next to each other, if we find a
+      // non-equivalent value after an equivalent one it means that we won't
+      // find any new equivalent value.
+      while (__ite._M_cur && this->_M_node_equals(*__beg._M_cur, *__ite._M_cur))
+	++__ite;
+
+      return { __beg, __ite };
+    }
+
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    auto
+    _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+	       _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
+    equal_range(const key_type& __k) const
+    -> pair<const_iterator, const_iterator>
+    {
+      auto __ite = find(__k);
+      if (!__ite._M_cur)
+	return { __ite, __ite };
+
+      auto __beg = __ite++;
+      if (__unique_keys::value)
+	return { __beg, __ite };
+
+      // All equivalent values are next to each other, if we find a
+      // non-equivalent value after an equivalent one it means that we won't
+      // find any new equivalent value.
+      while (__ite._M_cur && this->_M_node_equals(*__beg._M_cur, *__ite._M_cur))
+	++__ite;
+
+      return { __beg, __ite };
+    }
+
+#if __cplusplus > 201703L
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    template<typename _Kt, typename, typename>
+      auto
+      _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+		 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
+      _M_equal_range_tr(const _Kt& __k)
+      -> pair<iterator, iterator>
+      {
+	__hash_code __code = this->_M_hash_code_tr(__k);
+	std::size_t __bkt = _M_bucket_index(__code);
+	auto __n = _M_find_node_tr(__bkt, __k, __code);
+	iterator __ite(__n);
+	if (!__n)
+	  return { __ite, __ite };
+
+	// All equivalent values are next to each other, if we find a
+	// non-equivalent value after an equivalent one it means that we won't
+	// find any new equivalent value.
+	auto __beg = __ite++;
+	while (__ite._M_cur && this->_M_equals_tr(__k, __code, *__ite._M_cur))
+	  ++__ite;
+
+	return { __beg, __ite };
+      }
+
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    template<typename _Kt, typename, typename>
+      auto
+      _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+		 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
+      _M_equal_range_tr(const _Kt& __k) const
+      -> pair<const_iterator, const_iterator>
+      {
+	__hash_code __code = this->_M_hash_code_tr(__k);
+	std::size_t __bkt = _M_bucket_index(__code);
+	auto __n = _M_find_node_tr(__bkt, __k, __code);
+	const_iterator __ite(__n);
+	if (!__n)
+	  return { __ite, __ite };
+
+	// All equivalent values are next to each other, if we find a
+	// non-equivalent value after an equivalent one it means that we won't
+	// find any new equivalent value.
+	auto __beg = __ite++;
+	while (__ite._M_cur && this->_M_equals_tr(__k, __code, *__ite._M_cur))
+	  ++__ite;
+
+	return { __beg, __ite };
+      }
+#endif
+
+  // Find the node before the one whose key compares equal to k.
+  // Return nullptr if no node is found.
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    auto
+    _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+	       _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
+    _M_find_before_node(const key_type& __k)
+    -> __node_base_ptr
+    {
+      __node_base_ptr __prev_p = &_M_before_begin;
+      if (!__prev_p->_M_nxt)
+	return nullptr;
+
+      for (__node_ptr __p = static_cast<__node_ptr>(__prev_p->_M_nxt);
+	   __p != nullptr;
+	   __p = __p->_M_next())
+	{
+	  if (this->_M_key_equals(__k, *__p))
+	    return __prev_p;
+
+	  __prev_p = __p;
+	}
+
+      return nullptr;
+    }
+
+  // Find the node before the one whose key compares equal to k in the bucket
+  // bkt. Return nullptr if no node is found.
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    auto
+    _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+	       _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
+    _M_find_before_node(size_type __bkt, const key_type& __k,
+			__hash_code __code) const
+    -> __node_base_ptr
+    {
+      __node_base_ptr __prev_p = _M_buckets[__bkt];
+      if (!__prev_p)
+	return nullptr;
+
+      for (__node_ptr __p = static_cast<__node_ptr>(__prev_p->_M_nxt);;
+	   __p = __p->_M_next())
+	{
+	  if (this->_M_equals(__k, __code, *__p))
+	    return __prev_p;
+
+	  if (!__p->_M_nxt || _M_bucket_index(*__p->_M_next()) != __bkt)
+	    break;
+	  __prev_p = __p;
+	}
+
+      return nullptr;
+    }
+
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    template<typename _Kt>
+      auto
+      _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+		 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
+      _M_find_before_node_tr(size_type __bkt, const _Kt& __k,
+			     __hash_code __code) const
+      -> __node_base_ptr
+      {
+	__node_base_ptr __prev_p = _M_buckets[__bkt];
+	if (!__prev_p)
+	  return nullptr;
+
+	for (__node_ptr __p = static_cast<__node_ptr>(__prev_p->_M_nxt);;
+	     __p = __p->_M_next())
+	  {
+	    if (this->_M_equals_tr(__k, __code, *__p))
+	      return __prev_p;
+
+	    if (!__p->_M_nxt || _M_bucket_index(*__p->_M_next()) != __bkt)
+	      break;
+	    __prev_p = __p;
+	  }
+
+	return nullptr;
+      }
+
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    void
+    _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+	       _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
+    _M_insert_bucket_begin(size_type __bkt, __node_ptr __node)
+    {
+      if (_M_buckets[__bkt])
+	{
+	  // Bucket is not empty, we just need to insert the new node
+	  // after the bucket before begin.
+	  __node->_M_nxt = _M_buckets[__bkt]->_M_nxt;
+	  _M_buckets[__bkt]->_M_nxt = __node;
+	}
+      else
+	{
+	  // The bucket is empty, the new node is inserted at the
+	  // beginning of the singly-linked list and the bucket will
+	  // contain _M_before_begin pointer.
+	  __node->_M_nxt = _M_before_begin._M_nxt;
+	  _M_before_begin._M_nxt = __node;
+
+	  if (__node->_M_nxt)
+	    // We must update former begin bucket that is pointing to
+	    // _M_before_begin.
+	    _M_buckets[_M_bucket_index(*__node->_M_next())] = __node;
+
+	  _M_buckets[__bkt] = &_M_before_begin;
+	}
+    }
+
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    void
+    _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+	       _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
+    _M_remove_bucket_begin(size_type __bkt, __node_ptr __next,
+			   size_type __next_bkt)
+    {
+      if (!__next || __next_bkt != __bkt)
+	{
+	  // Bucket is now empty
+	  // First update next bucket if any
+	  if (__next)
+	    _M_buckets[__next_bkt] = _M_buckets[__bkt];
+
+	  // Second update before begin node if necessary
+	  if (&_M_before_begin == _M_buckets[__bkt])
+	    _M_before_begin._M_nxt = __next;
+	  _M_buckets[__bkt] = nullptr;
+	}
+    }
+
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    auto
+    _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+	       _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
+    _M_get_previous_node(size_type __bkt, __node_ptr __n)
+    -> __node_base_ptr
+    {
+      __node_base_ptr __prev_n = _M_buckets[__bkt];
+      while (__prev_n->_M_nxt != __n)
+	__prev_n = __prev_n->_M_nxt;
+      return __prev_n;
+    }
+
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    template<typename... _Args>
+      auto
+      _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+		 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
+      _M_emplace(true_type /* __uks */, _Args&&... __args)
+      -> pair<iterator, bool>
+      {
+	// First build the node to get access to the hash code
+	_Scoped_node __node { this, std::forward<_Args>(__args)...  };
+	const key_type& __k = _ExtractKey{}(__node._M_node->_M_v());
+	if (size() <= __small_size_threshold())
+	  {
+	    for (auto __it = begin(); __it != end(); ++__it)
+	      if (this->_M_key_equals(__k, *__it._M_cur))
+		// There is already an equivalent node, no insertion
+		return { __it, false };
+	  }
+
+	__hash_code __code = this->_M_hash_code(__k);
+	size_type __bkt = _M_bucket_index(__code);
+	if (size() > __small_size_threshold())
+	  if (__node_ptr __p = _M_find_node(__bkt, __k, __code))
+	    // There is already an equivalent node, no insertion
+	    return { iterator(__p), false };
+
+	// Insert the node
+	auto __pos = _M_insert_unique_node(__bkt, __code, __node._M_node);
+	__node._M_node = nullptr;
+	return { __pos, true };
+      }
+
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    template<typename... _Args>
+      auto
+      _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+		 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
+      _M_emplace(const_iterator __hint, false_type /* __uks */,
+		 _Args&&... __args)
+      -> iterator
+      {
+	// First build the node to get its hash code.
+	_Scoped_node __node { this, std::forward<_Args>(__args)...  };
+	const key_type& __k = _ExtractKey{}(__node._M_node->_M_v());
+
+	auto __res = this->_M_compute_hash_code(__hint, __k);
+	auto __pos
+	  = _M_insert_multi_node(__res.first._M_cur, __res.second,
+				 __node._M_node);
+	__node._M_node = nullptr;
+	return __pos;
+      }
+
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    auto
+    _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+	       _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
+    _M_compute_hash_code(const_iterator __hint, const key_type& __k) const
+    -> pair<const_iterator, __hash_code>
+    {
+      if (size() <= __small_size_threshold())
+	{
+	  if (__hint != cend())
+	    {
+	      for (auto __it = __hint; __it != cend(); ++__it)
+		if (this->_M_key_equals(__k, *__it._M_cur))
+		  return { __it, this->_M_hash_code(*__it._M_cur) };
+	    }
+
+	  for (auto __it = cbegin(); __it != __hint; ++__it)
+	    if (this->_M_key_equals(__k, *__it._M_cur))
+	      return { __it, this->_M_hash_code(*__it._M_cur) };
+	}
+
+      return { __hint, this->_M_hash_code(__k) };
+    }
+
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    auto
+    _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+	       _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
+    _M_insert_unique_node(size_type __bkt, __hash_code __code,
+			  __node_ptr __node, size_type __n_elt)
+    -> iterator
+    {
+      const __rehash_state& __saved_state = _M_rehash_policy._M_state();
+      std::pair<bool, std::size_t> __do_rehash
+	= _M_rehash_policy._M_need_rehash(_M_bucket_count, _M_element_count,
+					  __n_elt);
+
+      if (__do_rehash.first)
+	{
+	  _M_rehash(__do_rehash.second, __saved_state);
+	  __bkt = _M_bucket_index(__code);
+	}
+
+      this->_M_store_code(*__node, __code);
+
+      // Always insert at the beginning of the bucket.
+      _M_insert_bucket_begin(__bkt, __node);
+      ++_M_element_count;
+      return iterator(__node);
+    }
+
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    auto
+    _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+	       _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
+    _M_insert_multi_node(__node_ptr __hint,
+			 __hash_code __code, __node_ptr __node)
+    -> iterator
+    {
+      const __rehash_state& __saved_state = _M_rehash_policy._M_state();
+      std::pair<bool, std::size_t> __do_rehash
+	= _M_rehash_policy._M_need_rehash(_M_bucket_count, _M_element_count, 1);
+
+      if (__do_rehash.first)
+	_M_rehash(__do_rehash.second, __saved_state);
+
+      this->_M_store_code(*__node, __code);
+      const key_type& __k = _ExtractKey{}(__node->_M_v());
+      size_type __bkt = _M_bucket_index(__code);
+
+      // Find the node before an equivalent one or use hint if it exists and
+      // if it is equivalent.
+      __node_base_ptr __prev
+	= __builtin_expect(__hint != nullptr, false)
+	  && this->_M_equals(__k, __code, *__hint)
+	    ? __hint
+	    : _M_find_before_node(__bkt, __k, __code);
+
+      if (__prev)
+	{
+	  // Insert after the node before the equivalent one.
+	  __node->_M_nxt = __prev->_M_nxt;
+	  __prev->_M_nxt = __node;
+	  if (__builtin_expect(__prev == __hint, false))
+	    // hint might be the last bucket node, in this case we need to
+	    // update next bucket.
+	    if (__node->_M_nxt
+		&& !this->_M_equals(__k, __code, *__node->_M_next()))
+	      {
+		size_type __next_bkt = _M_bucket_index(*__node->_M_next());
+		if (__next_bkt != __bkt)
+		  _M_buckets[__next_bkt] = __node;
+	      }
+	}
+      else
+	// The inserted node has no equivalent in the hashtable. We must
+	// insert the new node at the beginning of the bucket to preserve
+	// equivalent elements' relative positions.
+	_M_insert_bucket_begin(__bkt, __node);
+      ++_M_element_count;
+      return iterator(__node);
+    }
+
+  // Insert v if no element with its key is already present.
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    template<typename _Kt, typename _Arg, typename _NodeGenerator>
+      auto
+      _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+		 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
+      _M_insert_unique(_Kt&& __k, _Arg&& __v,
+		       const _NodeGenerator& __node_gen)
+      -> pair<iterator, bool>
+      {
+	if (size() <= __small_size_threshold())
+	  for (auto __it = begin(); __it != end(); ++__it)
+	    if (this->_M_key_equals_tr(__k, *__it._M_cur))
+	      return { __it, false };
+
+	__hash_code __code = this->_M_hash_code_tr(__k);
+	size_type __bkt = _M_bucket_index(__code);
+
+	if (size() > __small_size_threshold())
+	  if (__node_ptr __node = _M_find_node_tr(__bkt, __k, __code))
+	    return { iterator(__node), false };
+
+	_Scoped_node __node {
+	  __node_builder_t::_S_build(std::forward<_Kt>(__k),
+				     std::forward<_Arg>(__v),
+				     __node_gen),
+	  this
+	};
+	auto __pos
+	  = _M_insert_unique_node(__bkt, __code, __node._M_node);
+	__node._M_node = nullptr;
+	return { __pos, true };
+      }
+
+  // Insert v unconditionally.
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    template<typename _Arg, typename _NodeGenerator>
+      auto
+      _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+		 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
+      _M_insert(const_iterator __hint, _Arg&& __v,
+		const _NodeGenerator& __node_gen,
+		false_type /* __uks */)
+      -> iterator
+      {
+	// First allocate new node so that we don't do anything if it throws.
+	_Scoped_node __node{ __node_gen(std::forward<_Arg>(__v)), this };
+
+	// Second compute the hash code so that we don't rehash if it throws.
+	auto __res = this->_M_compute_hash_code(
+	  __hint, _ExtractKey{}(__node._M_node->_M_v()));
+
+	auto __pos
+	  = _M_insert_multi_node(__res.first._M_cur, __res.second,
+				 __node._M_node);
+	__node._M_node = nullptr;
+	return __pos;
+      }
+
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    auto
+    _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+	       _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
+    erase(const_iterator __it)
+    -> iterator
+    {
+      __node_ptr __n = __it._M_cur;
+      std::size_t __bkt = _M_bucket_index(*__n);
+
+      // Look for previous node to unlink it from the erased one, this
+      // is why we need buckets to contain the before begin to make
+      // this search fast.
+      __node_base_ptr __prev_n = _M_get_previous_node(__bkt, __n);
+      return _M_erase(__bkt, __prev_n, __n);
+    }
+
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    auto
+    _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+	       _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
+    _M_erase(size_type __bkt, __node_base_ptr __prev_n, __node_ptr __n)
+    -> iterator
+    {
+      if (__prev_n == _M_buckets[__bkt])
+	_M_remove_bucket_begin(__bkt, __n->_M_next(),
+	  __n->_M_nxt ? _M_bucket_index(*__n->_M_next()) : 0);
+      else if (__n->_M_nxt)
+	{
+	  size_type __next_bkt = _M_bucket_index(*__n->_M_next());
+	  if (__next_bkt != __bkt)
+	    _M_buckets[__next_bkt] = __prev_n;
+	}
+
+      __prev_n->_M_nxt = __n->_M_nxt;
+      iterator __result(__n->_M_next());
+      this->_M_deallocate_node(__n);
+      --_M_element_count;
+
+      return __result;
+    }
+
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    auto
+    _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+	       _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
+    _M_erase(true_type /* __uks */, const key_type& __k)
+    -> size_type
+    {
+      __node_base_ptr __prev_n;
+      __node_ptr __n;
+      std::size_t __bkt;
+      if (size() <= __small_size_threshold())
+	{
+	  __prev_n = _M_find_before_node(__k);
+	  if (!__prev_n)
+	    return 0;
+
+	  // We found a matching node, erase it.
+	  __n = static_cast<__node_ptr>(__prev_n->_M_nxt);
+	  __bkt = _M_bucket_index(*__n);
+	}
+      else
+	{
+	  __hash_code __code = this->_M_hash_code(__k);
+	  __bkt = _M_bucket_index(__code);
+
+	  // Look for the node before the first matching node.
+	  __prev_n = _M_find_before_node(__bkt, __k, __code);
+	  if (!__prev_n)
+	    return 0;
+
+	  // We found a matching node, erase it.
+	  __n = static_cast<__node_ptr>(__prev_n->_M_nxt);
+	}
+
+      _M_erase(__bkt, __prev_n, __n);
+      return 1;
+    }
+
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    auto
+    _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+	       _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
+    _M_erase(false_type /* __uks */, const key_type& __k)
+    -> size_type
+    {
+      std::size_t __bkt;
+      __node_base_ptr __prev_n;
+      __node_ptr __n;
+      if (size() <= __small_size_threshold())
+	{
+	  __prev_n = _M_find_before_node(__k);
+	  if (!__prev_n)
+	    return 0;
+
+	  // We found a matching node, erase it.
+	  __n = static_cast<__node_ptr>(__prev_n->_M_nxt);
+	  __bkt = _M_bucket_index(*__n);
+	}
+      else
+	{
+	  __hash_code __code = this->_M_hash_code(__k);
+	  __bkt = _M_bucket_index(__code);
+
+	  // Look for the node before the first matching node.
+	  __prev_n = _M_find_before_node(__bkt, __k, __code);
+	  if (!__prev_n)
+	    return 0;
+
+	  __n = static_cast<__node_ptr>(__prev_n->_M_nxt);
+	}
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 526. Is it undefined if a function in the standard changes
+      // in parameters?
+      // We use one loop to find all matching nodes and another to deallocate
+      // them so that the key stays valid during the first loop. It might be
+      // invalidated indirectly when destroying nodes.
+      __node_ptr __n_last = __n->_M_next();
+      while (__n_last && this->_M_node_equals(*__n, *__n_last))
+	__n_last = __n_last->_M_next();
+
+      std::size_t __n_last_bkt = __n_last ? _M_bucket_index(*__n_last) : __bkt;
+
+      // Deallocate nodes.
+      size_type __result = 0;
+      do
+	{
+	  __node_ptr __p = __n->_M_next();
+	  this->_M_deallocate_node(__n);
+	  __n = __p;
+	  ++__result;
+	}
+      while (__n != __n_last);
+
+      _M_element_count -= __result;
+      if (__prev_n == _M_buckets[__bkt])
+	_M_remove_bucket_begin(__bkt, __n_last, __n_last_bkt);
+      else if (__n_last_bkt != __bkt)
+	_M_buckets[__n_last_bkt] = __prev_n;
+      __prev_n->_M_nxt = __n_last;
+      return __result;
+    }
+
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    auto
+    _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+	       _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
+    erase(const_iterator __first, const_iterator __last)
+    -> iterator
+    {
+      __node_ptr __n = __first._M_cur;
+      __node_ptr __last_n = __last._M_cur;
+      if (__n == __last_n)
+	return iterator(__n);
+
+      std::size_t __bkt = _M_bucket_index(*__n);
+
+      __node_base_ptr __prev_n = _M_get_previous_node(__bkt, __n);
+      bool __is_bucket_begin = __n == _M_bucket_begin(__bkt);
+      std::size_t __n_bkt = __bkt;
+      for (;;)
+	{
+	  do
+	    {
+	      __node_ptr __tmp = __n;
+	      __n = __n->_M_next();
+	      this->_M_deallocate_node(__tmp);
+	      --_M_element_count;
+	      if (!__n)
+		break;
+	      __n_bkt = _M_bucket_index(*__n);
+	    }
+	  while (__n != __last_n && __n_bkt == __bkt);
+	  if (__is_bucket_begin)
+	    _M_remove_bucket_begin(__bkt, __n, __n_bkt);
+	  if (__n == __last_n)
+	    break;
+	  __is_bucket_begin = true;
+	  __bkt = __n_bkt;
+	}
+
+      if (__n && (__n_bkt != __bkt || __is_bucket_begin))
+	_M_buckets[__n_bkt] = __prev_n;
+      __prev_n->_M_nxt = __n;
+      return iterator(__n);
+    }
+
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    void
+    _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+	       _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
+    clear() noexcept
+    {
+      this->_M_deallocate_nodes(_M_begin());
+      __builtin_memset(_M_buckets, 0,
+		       _M_bucket_count * sizeof(__node_base_ptr));
+      _M_element_count = 0;
+      _M_before_begin._M_nxt = nullptr;
+    }
+
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    void
+    _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+	       _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
+    rehash(size_type __bkt_count)
+    {
+      const __rehash_state& __saved_state = _M_rehash_policy._M_state();
+      __bkt_count
+	= std::max(_M_rehash_policy._M_bkt_for_elements(_M_element_count + 1),
+		   __bkt_count);
+      __bkt_count = _M_rehash_policy._M_next_bkt(__bkt_count);
+
+      if (__bkt_count != _M_bucket_count)
+	_M_rehash(__bkt_count, __saved_state);
+      else
+	// No rehash, restore previous state to keep it consistent with
+	// container state.
+	_M_rehash_policy._M_reset(__saved_state);
+    }
+
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    void
+    _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+	       _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
+    _M_rehash(size_type __bkt_count, const __rehash_state& __state)
+    {
+      __try
+	{
+	  _M_rehash_aux(__bkt_count, __unique_keys{});
+	}
+      __catch(...)
+	{
+	  // A failure here means that buckets allocation failed.  We only
+	  // have to restore hash policy previous state.
+	  _M_rehash_policy._M_reset(__state);
+	  __throw_exception_again;
+	}
+    }
+
+  // Rehash when there is no equivalent elements.
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    void
+    _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+	       _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
+    _M_rehash_aux(size_type __bkt_count, true_type /* __uks */)
+    {
+      __buckets_ptr __new_buckets = _M_allocate_buckets(__bkt_count);
+      __node_ptr __p = _M_begin();
+      _M_before_begin._M_nxt = nullptr;
+      std::size_t __bbegin_bkt = 0;
+      while (__p)
+	{
+	  __node_ptr __next = __p->_M_next();
+	  std::size_t __bkt
+	    = __hash_code_base::_M_bucket_index(*__p, __bkt_count);
+	  if (!__new_buckets[__bkt])
+	    {
+	      __p->_M_nxt = _M_before_begin._M_nxt;
+	      _M_before_begin._M_nxt = __p;
+	      __new_buckets[__bkt] = &_M_before_begin;
+	      if (__p->_M_nxt)
+		__new_buckets[__bbegin_bkt] = __p;
+	      __bbegin_bkt = __bkt;
+	    }
+	  else
+	    {
+	      __p->_M_nxt = __new_buckets[__bkt]->_M_nxt;
+	      __new_buckets[__bkt]->_M_nxt = __p;
+	    }
+
+	  __p = __next;
+	}
+
+      _M_deallocate_buckets();
+      _M_bucket_count = __bkt_count;
+      _M_buckets = __new_buckets;
+    }
+
+  // Rehash when there can be equivalent elements, preserve their relative
+  // order.
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    void
+    _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+	       _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
+    _M_rehash_aux(size_type __bkt_count, false_type /* __uks */)
+    {
+      __buckets_ptr __new_buckets = _M_allocate_buckets(__bkt_count);
+      __node_ptr __p = _M_begin();
+      _M_before_begin._M_nxt = nullptr;
+      std::size_t __bbegin_bkt = 0;
+      std::size_t __prev_bkt = 0;
+      __node_ptr __prev_p = nullptr;
+      bool __check_bucket = false;
+
+      while (__p)
+	{
+	  __node_ptr __next = __p->_M_next();
+	  std::size_t __bkt
+	    = __hash_code_base::_M_bucket_index(*__p, __bkt_count);
+
+	  if (__prev_p && __prev_bkt == __bkt)
+	    {
+	      // Previous insert was already in this bucket, we insert after
+	      // the previously inserted one to preserve equivalent elements
+	      // relative order.
+	      __p->_M_nxt = __prev_p->_M_nxt;
+	      __prev_p->_M_nxt = __p;
+
+	      // Inserting after a node in a bucket require to check that we
+	      // haven't change the bucket last node, in this case next
+	      // bucket containing its before begin node must be updated. We
+	      // schedule a check as soon as we move out of the sequence of
+	      // equivalent nodes to limit the number of checks.
+	      __check_bucket = true;
+	    }
+	  else
+	    {
+	      if (__check_bucket)
+		{
+		  // Check if we shall update the next bucket because of
+		  // insertions into __prev_bkt bucket.
+		  if (__prev_p->_M_nxt)
+		    {
+		      std::size_t __next_bkt
+			= __hash_code_base::_M_bucket_index(
+			  *__prev_p->_M_next(), __bkt_count);
+		      if (__next_bkt != __prev_bkt)
+			__new_buckets[__next_bkt] = __prev_p;
+		    }
+		  __check_bucket = false;
+		}
+
+	      if (!__new_buckets[__bkt])
+		{
+		  __p->_M_nxt = _M_before_begin._M_nxt;
+		  _M_before_begin._M_nxt = __p;
+		  __new_buckets[__bkt] = &_M_before_begin;
+		  if (__p->_M_nxt)
+		    __new_buckets[__bbegin_bkt] = __p;
+		  __bbegin_bkt = __bkt;
+		}
+	      else
+		{
+		  __p->_M_nxt = __new_buckets[__bkt]->_M_nxt;
+		  __new_buckets[__bkt]->_M_nxt = __p;
+		}
+	    }
+	  __prev_p = __p;
+	  __prev_bkt = __bkt;
+	  __p = __next;
+	}
+
+      if (__check_bucket && __prev_p->_M_nxt)
+	{
+	  std::size_t __next_bkt
+	    = __hash_code_base::_M_bucket_index(*__prev_p->_M_next(),
+						__bkt_count);
+	  if (__next_bkt != __prev_bkt)
+	    __new_buckets[__next_bkt] = __prev_p;
+	}
+
+      _M_deallocate_buckets();
+      _M_bucket_count = __bkt_count;
+      _M_buckets = __new_buckets;
+    }
+
+#if __cplusplus > 201402L
+  template<typename, typename, typename> class _Hash_merge_helper { };
+#endif // C++17
+
+#if __cpp_deduction_guides >= 201606
+  // Used to constrain deduction guides
+  template<typename _Hash>
+    using _RequireNotAllocatorOrIntegral
+      = __enable_if_t<!__or_<is_integral<_Hash>, __is_allocator<_Hash>>::value>;
+#endif
+
+/// @endcond
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif // _HASHTABLE_H
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@hashtable_policy.h
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+// Internal policy header for unordered_set and unordered_map -*- C++ -*-
+
+// Copyright (C) 2010-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/hashtable_policy.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly.
+ *  @headername{unordered_map,unordered_set}
+ */
+
+#ifndef _HASHTABLE_POLICY_H
+#define _HASHTABLE_POLICY_H 1
+
+#include <tuple>		// for std::tuple, std::forward_as_tuple
+#include <bits/stl_algobase.h>	// for std::min, std::is_permutation.
+#include <ext/aligned_buffer.h>	// for __gnu_cxx::__aligned_buffer
+#include <ext/alloc_traits.h>	// for std::__alloc_rebind
+#include <ext/numeric_traits.h>	// for __gnu_cxx::__int_traits
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+/// @cond undocumented
+
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    class _Hashtable;
+
+namespace __detail
+{
+  /**
+   *  @defgroup hashtable-detail Base and Implementation Classes
+   *  @ingroup unordered_associative_containers
+   *  @{
+   */
+  template<typename _Key, typename _Value, typename _ExtractKey,
+	   typename _Equal, typename _Hash, typename _RangeHash,
+	   typename _Unused, typename _Traits>
+    struct _Hashtable_base;
+
+  // Helper function: return distance(first, last) for forward
+  // iterators, or 0/1 for input iterators.
+  template<typename _Iterator>
+    inline typename std::iterator_traits<_Iterator>::difference_type
+    __distance_fw(_Iterator __first, _Iterator __last,
+		  std::input_iterator_tag)
+    { return __first != __last ? 1 : 0; }
+
+  template<typename _Iterator>
+    inline typename std::iterator_traits<_Iterator>::difference_type
+    __distance_fw(_Iterator __first, _Iterator __last,
+		  std::forward_iterator_tag)
+    { return std::distance(__first, __last); }
+
+  template<typename _Iterator>
+    inline typename std::iterator_traits<_Iterator>::difference_type
+    __distance_fw(_Iterator __first, _Iterator __last)
+    { return __distance_fw(__first, __last,
+			   std::__iterator_category(__first)); }
+
+  struct _Identity
+  {
+    template<typename _Tp>
+      _Tp&&
+      operator()(_Tp&& __x) const noexcept
+      { return std::forward<_Tp>(__x); }
+  };
+
+  struct _Select1st
+  {
+    template<typename _Pair>
+      struct __1st_type;
+
+    template<typename _Tp, typename _Up>
+      struct __1st_type<pair<_Tp, _Up>>
+      { using type = _Tp; };
+
+    template<typename _Tp, typename _Up>
+      struct __1st_type<const pair<_Tp, _Up>>
+      { using type = const _Tp; };
+
+    template<typename _Pair>
+      struct __1st_type<_Pair&>
+      { using type = typename __1st_type<_Pair>::type&; };
+
+    template<typename _Tp>
+      typename __1st_type<_Tp>::type&&
+      operator()(_Tp&& __x) const noexcept
+      { return std::forward<_Tp>(__x).first; }
+  };
+
+  template<typename _ExKey>
+    struct _NodeBuilder;
+
+  template<>
+    struct _NodeBuilder<_Select1st>
+    {
+      template<typename _Kt, typename _Arg, typename _NodeGenerator>
+	static auto
+	_S_build(_Kt&& __k, _Arg&& __arg, const _NodeGenerator& __node_gen)
+	-> typename _NodeGenerator::__node_type*
+	{
+	  return __node_gen(std::forward<_Kt>(__k),
+			    std::forward<_Arg>(__arg).second);
+	}
+    };
+
+  template<>
+    struct _NodeBuilder<_Identity>
+    {
+      template<typename _Kt, typename _Arg, typename _NodeGenerator>
+	static auto
+	_S_build(_Kt&& __k, _Arg&&, const _NodeGenerator& __node_gen)
+	-> typename _NodeGenerator::__node_type*
+	{ return __node_gen(std::forward<_Kt>(__k)); }
+    };
+
+  template<typename _NodeAlloc>
+    struct _Hashtable_alloc;
+
+  // Functor recycling a pool of nodes and using allocation once the pool is
+  // empty.
+  template<typename _NodeAlloc>
+    struct _ReuseOrAllocNode
+    {
+    private:
+      using __node_alloc_type = _NodeAlloc;
+      using __hashtable_alloc = _Hashtable_alloc<__node_alloc_type>;
+      using __node_alloc_traits =
+	typename __hashtable_alloc::__node_alloc_traits;
+
+    public:
+      using __node_type = typename __hashtable_alloc::__node_type;
+
+      _ReuseOrAllocNode(__node_type* __nodes, __hashtable_alloc& __h)
+      : _M_nodes(__nodes), _M_h(__h) { }
+      _ReuseOrAllocNode(const _ReuseOrAllocNode&) = delete;
+
+      ~_ReuseOrAllocNode()
+      { _M_h._M_deallocate_nodes(_M_nodes); }
+
+      template<typename... _Args>
+	__node_type*
+	operator()(_Args&&... __args) const
+	{
+	  if (_M_nodes)
+	    {
+	      __node_type* __node = _M_nodes;
+	      _M_nodes = _M_nodes->_M_next();
+	      __node->_M_nxt = nullptr;
+	      auto& __a = _M_h._M_node_allocator();
+	      __node_alloc_traits::destroy(__a, __node->_M_valptr());
+	      __try
+		{
+		  __node_alloc_traits::construct(__a, __node->_M_valptr(),
+						 std::forward<_Args>(__args)...);
+		}
+	      __catch(...)
+		{
+		  _M_h._M_deallocate_node_ptr(__node);
+		  __throw_exception_again;
+		}
+	      return __node;
+	    }
+	  return _M_h._M_allocate_node(std::forward<_Args>(__args)...);
+	}
+
+    private:
+      mutable __node_type* _M_nodes;
+      __hashtable_alloc& _M_h;
+    };
+
+  // Functor similar to the previous one but without any pool of nodes to
+  // recycle.
+  template<typename _NodeAlloc>
+    struct _AllocNode
+    {
+    private:
+      using __hashtable_alloc = _Hashtable_alloc<_NodeAlloc>;
+
+    public:
+      using __node_type = typename __hashtable_alloc::__node_type;
+
+      _AllocNode(__hashtable_alloc& __h)
+      : _M_h(__h) { }
+
+      template<typename... _Args>
+	__node_type*
+	operator()(_Args&&... __args) const
+	{ return _M_h._M_allocate_node(std::forward<_Args>(__args)...); }
+
+    private:
+      __hashtable_alloc& _M_h;
+    };
+
+  // Auxiliary types used for all instantiations of _Hashtable nodes
+  // and iterators.
+
+  /**
+   *  struct _Hashtable_traits
+   *
+   *  Important traits for hash tables.
+   *
+   *  @tparam _Cache_hash_code  Boolean value. True if the value of
+   *  the hash function is stored along with the value. This is a
+   *  time-space tradeoff.  Storing it may improve lookup speed by
+   *  reducing the number of times we need to call the _Hash or _Equal
+   *  functors.
+   *
+   *  @tparam _Constant_iterators  Boolean value. True if iterator and
+   *  const_iterator are both constant iterator types. This is true
+   *  for unordered_set and unordered_multiset, false for
+   *  unordered_map and unordered_multimap.
+   *
+   *  @tparam _Unique_keys  Boolean value. True if the return value
+   *  of _Hashtable::count(k) is always at most one, false if it may
+   *  be an arbitrary number. This is true for unordered_set and
+   *  unordered_map, false for unordered_multiset and
+   *  unordered_multimap.
+   */
+  template<bool _Cache_hash_code, bool _Constant_iterators, bool _Unique_keys>
+    struct _Hashtable_traits
+    {
+      using __hash_cached = __bool_constant<_Cache_hash_code>;
+      using __constant_iterators = __bool_constant<_Constant_iterators>;
+      using __unique_keys = __bool_constant<_Unique_keys>;
+    };
+
+  /**
+   *  struct _Hashtable_hash_traits
+   *
+   *  Important traits for hash tables depending on associated hasher.
+   *
+   */
+  template<typename _Hash>
+    struct _Hashtable_hash_traits
+    {
+      static constexpr std::size_t
+      __small_size_threshold() noexcept
+      { return std::__is_fast_hash<_Hash>::value ? 0 : 20; }
+    };
+
+  /**
+   *  struct _Hash_node_base
+   *
+   *  Nodes, used to wrap elements stored in the hash table.  A policy
+   *  template parameter of class template _Hashtable controls whether
+   *  nodes also store a hash code. In some cases (e.g. strings) this
+   *  may be a performance win.
+   */
+  struct _Hash_node_base
+  {
+    _Hash_node_base* _M_nxt;
+
+    _Hash_node_base() noexcept : _M_nxt() { }
+
+    _Hash_node_base(_Hash_node_base* __next) noexcept : _M_nxt(__next) { }
+  };
+
+  /**
+   *  struct _Hash_node_value_base
+   *
+   *  Node type with the value to store.
+   */
+  template<typename _Value>
+    struct _Hash_node_value_base
+    {
+      typedef _Value value_type;
+
+      __gnu_cxx::__aligned_buffer<_Value> _M_storage;
+
+      _Value*
+      _M_valptr() noexcept
+      { return _M_storage._M_ptr(); }
+
+      const _Value*
+      _M_valptr() const noexcept
+      { return _M_storage._M_ptr(); }
+
+      _Value&
+      _M_v() noexcept
+      { return *_M_valptr(); }
+
+      const _Value&
+      _M_v() const noexcept
+      { return *_M_valptr(); }
+    };
+
+  /**
+   *  Primary template struct _Hash_node_code_cache.
+   */
+  template<bool _Cache_hash_code>
+    struct _Hash_node_code_cache
+    { };
+
+  /**
+   *  Specialization for node with cache, struct _Hash_node_code_cache.
+   */
+  template<>
+    struct _Hash_node_code_cache<true>
+    { std::size_t  _M_hash_code; };
+
+  template<typename _Value, bool _Cache_hash_code>
+    struct _Hash_node_value
+    : _Hash_node_value_base<_Value>
+    , _Hash_node_code_cache<_Cache_hash_code>
+    { };
+
+  /**
+   *  Primary template struct _Hash_node.
+   */
+  template<typename _Value, bool _Cache_hash_code>
+    struct _Hash_node
+    : _Hash_node_base
+    , _Hash_node_value<_Value, _Cache_hash_code>
+    {
+      _Hash_node*
+      _M_next() const noexcept
+      { return static_cast<_Hash_node*>(this->_M_nxt); }
+    };
+
+  /// Base class for node iterators.
+  template<typename _Value, bool _Cache_hash_code>
+    struct _Node_iterator_base
+    {
+      using __node_type = _Hash_node<_Value, _Cache_hash_code>;
+
+      __node_type* _M_cur;
+
+      _Node_iterator_base() : _M_cur(nullptr) { }
+      _Node_iterator_base(__node_type* __p) noexcept
+      : _M_cur(__p) { }
+
+      void
+      _M_incr() noexcept
+      { _M_cur = _M_cur->_M_next(); }
+
+      friend bool
+      operator==(const _Node_iterator_base& __x, const _Node_iterator_base& __y)
+      noexcept
+      { return __x._M_cur == __y._M_cur; }
+
+#if __cpp_impl_three_way_comparison < 201907L
+      friend bool
+      operator!=(const _Node_iterator_base& __x, const _Node_iterator_base& __y)
+      noexcept
+      { return __x._M_cur != __y._M_cur; }
+#endif
+    };
+
+  /// Node iterators, used to iterate through all the hashtable.
+  template<typename _Value, bool __constant_iterators, bool __cache>
+    struct _Node_iterator
+    : public _Node_iterator_base<_Value, __cache>
+    {
+    private:
+      using __base_type = _Node_iterator_base<_Value, __cache>;
+      using __node_type = typename __base_type::__node_type;
+
+    public:
+      using value_type = _Value;
+      using difference_type = std::ptrdiff_t;
+      using iterator_category = std::forward_iterator_tag;
+
+      using pointer = __conditional_t<__constant_iterators,
+				      const value_type*, value_type*>;
+
+      using reference = __conditional_t<__constant_iterators,
+					const value_type&, value_type&>;
+
+      _Node_iterator() = default;
+
+      explicit
+      _Node_iterator(__node_type* __p) noexcept
+      : __base_type(__p) { }
+
+      reference
+      operator*() const noexcept
+      { return this->_M_cur->_M_v(); }
+
+      pointer
+      operator->() const noexcept
+      { return this->_M_cur->_M_valptr(); }
+
+      _Node_iterator&
+      operator++() noexcept
+      {
+	this->_M_incr();
+	return *this;
+      }
+
+      _Node_iterator
+      operator++(int) noexcept
+      {
+	_Node_iterator __tmp(*this);
+	this->_M_incr();
+	return __tmp;
+      }
+    };
+
+  /// Node const_iterators, used to iterate through all the hashtable.
+  template<typename _Value, bool __constant_iterators, bool __cache>
+    struct _Node_const_iterator
+    : public _Node_iterator_base<_Value, __cache>
+    {
+    private:
+      using __base_type = _Node_iterator_base<_Value, __cache>;
+      using __node_type = typename __base_type::__node_type;
+
+    public:
+      typedef _Value					value_type;
+      typedef std::ptrdiff_t				difference_type;
+      typedef std::forward_iterator_tag			iterator_category;
+
+      typedef const value_type*				pointer;
+      typedef const value_type&				reference;
+
+      _Node_const_iterator() = default;
+
+      explicit
+      _Node_const_iterator(__node_type* __p) noexcept
+      : __base_type(__p) { }
+
+      _Node_const_iterator(const _Node_iterator<_Value, __constant_iterators,
+			   __cache>& __x) noexcept
+      : __base_type(__x._M_cur) { }
+
+      reference
+      operator*() const noexcept
+      { return this->_M_cur->_M_v(); }
+
+      pointer
+      operator->() const noexcept
+      { return this->_M_cur->_M_valptr(); }
+
+      _Node_const_iterator&
+      operator++() noexcept
+      {
+	this->_M_incr();
+	return *this;
+      }
+
+      _Node_const_iterator
+      operator++(int) noexcept
+      {
+	_Node_const_iterator __tmp(*this);
+	this->_M_incr();
+	return __tmp;
+      }
+    };
+
+  // Many of class template _Hashtable's template parameters are policy
+  // classes.  These are defaults for the policies.
+
+  /// Default range hashing function: use division to fold a large number
+  /// into the range [0, N).
+  struct _Mod_range_hashing
+  {
+    typedef std::size_t first_argument_type;
+    typedef std::size_t second_argument_type;
+    typedef std::size_t result_type;
+
+    result_type
+    operator()(first_argument_type __num,
+	       second_argument_type __den) const noexcept
+    { return __num % __den; }
+  };
+
+  /// Default ranged hash function H.  In principle it should be a
+  /// function object composed from objects of type H1 and H2 such that
+  /// h(k, N) = h2(h1(k), N), but that would mean making extra copies of
+  /// h1 and h2.  So instead we'll just use a tag to tell class template
+  /// hashtable to do that composition.
+  struct _Default_ranged_hash { };
+
+  /// Default value for rehash policy.  Bucket size is (usually) the
+  /// smallest prime that keeps the load factor small enough.
+  struct _Prime_rehash_policy
+  {
+    using __has_load_factor = true_type;
+
+    _Prime_rehash_policy(float __z = 1.0) noexcept
+    : _M_max_load_factor(__z), _M_next_resize(0) { }
+
+    float
+    max_load_factor() const noexcept
+    { return _M_max_load_factor; }
+
+    // Return a bucket size no smaller than n.
+    std::size_t
+    _M_next_bkt(std::size_t __n) const;
+
+    // Return a bucket count appropriate for n elements
+    std::size_t
+    _M_bkt_for_elements(std::size_t __n) const
+    { return __builtin_ceil(__n / (double)_M_max_load_factor); }
+
+    // __n_bkt is current bucket count, __n_elt is current element count,
+    // and __n_ins is number of elements to be inserted.  Do we need to
+    // increase bucket count?  If so, return make_pair(true, n), where n
+    // is the new bucket count.  If not, return make_pair(false, 0).
+    std::pair<bool, std::size_t>
+    _M_need_rehash(std::size_t __n_bkt, std::size_t __n_elt,
+		   std::size_t __n_ins) const;
+
+    typedef std::size_t _State;
+
+    _State
+    _M_state() const
+    { return _M_next_resize; }
+
+    void
+    _M_reset() noexcept
+    { _M_next_resize = 0; }
+
+    void
+    _M_reset(_State __state)
+    { _M_next_resize = __state; }
+
+    static const std::size_t _S_growth_factor = 2;
+
+    float		_M_max_load_factor;
+    mutable std::size_t	_M_next_resize;
+  };
+
+  /// Range hashing function assuming that second arg is a power of 2.
+  struct _Mask_range_hashing
+  {
+    typedef std::size_t first_argument_type;
+    typedef std::size_t second_argument_type;
+    typedef std::size_t result_type;
+
+    result_type
+    operator()(first_argument_type __num,
+	       second_argument_type __den) const noexcept
+    { return __num & (__den - 1); }
+  };
+
+  /// Compute closest power of 2 not less than __n
+  inline std::size_t
+  __clp2(std::size_t __n) noexcept
+  {
+    using __gnu_cxx::__int_traits;
+    // Equivalent to return __n ? std::bit_ceil(__n) : 0;
+    if (__n < 2)
+      return __n;
+    const unsigned __lz = sizeof(size_t) > sizeof(long)
+      ? __builtin_clzll(__n - 1ull)
+      : __builtin_clzl(__n - 1ul);
+    // Doing two shifts avoids undefined behaviour when __lz == 0.
+    return (size_t(1) << (__int_traits<size_t>::__digits - __lz - 1)) << 1;
+  }
+
+  /// Rehash policy providing power of 2 bucket numbers. Avoids modulo
+  /// operations.
+  struct _Power2_rehash_policy
+  {
+    using __has_load_factor = true_type;
+
+    _Power2_rehash_policy(float __z = 1.0) noexcept
+    : _M_max_load_factor(__z), _M_next_resize(0) { }
+
+    float
+    max_load_factor() const noexcept
+    { return _M_max_load_factor; }
+
+    // Return a bucket size no smaller than n (as long as n is not above the
+    // highest power of 2).
+    std::size_t
+    _M_next_bkt(std::size_t __n) noexcept
+    {
+      if (__n == 0)
+	// Special case on container 1st initialization with 0 bucket count
+	// hint. We keep _M_next_resize to 0 to make sure that next time we
+	// want to add an element allocation will take place.
+	return 1;
+
+      const auto __max_width = std::min<size_t>(sizeof(size_t), 8);
+      const auto __max_bkt = size_t(1) << (__max_width * __CHAR_BIT__ - 1);
+      std::size_t __res = __clp2(__n);
+
+      if (__res == 0)
+	__res = __max_bkt;
+      else if (__res == 1)
+	// If __res is 1 we force it to 2 to make sure there will be an
+	// allocation so that nothing need to be stored in the initial
+	// single bucket
+	__res = 2;
+
+      if (__res == __max_bkt)
+	// Set next resize to the max value so that we never try to rehash again
+	// as we already reach the biggest possible bucket number.
+	// Note that it might result in max_load_factor not being respected.
+	_M_next_resize = size_t(-1);
+      else
+	_M_next_resize
+	  = __builtin_floor(__res * (double)_M_max_load_factor);
+
+      return __res;
+    }
+
+    // Return a bucket count appropriate for n elements
+    std::size_t
+    _M_bkt_for_elements(std::size_t __n) const noexcept
+    { return __builtin_ceil(__n / (double)_M_max_load_factor); }
+
+    // __n_bkt is current bucket count, __n_elt is current element count,
+    // and __n_ins is number of elements to be inserted.  Do we need to
+    // increase bucket count?  If so, return make_pair(true, n), where n
+    // is the new bucket count.  If not, return make_pair(false, 0).
+    std::pair<bool, std::size_t>
+    _M_need_rehash(std::size_t __n_bkt, std::size_t __n_elt,
+		   std::size_t __n_ins) noexcept
+    {
+      if (__n_elt + __n_ins > _M_next_resize)
+	{
+	  // If _M_next_resize is 0 it means that we have nothing allocated so
+	  // far and that we start inserting elements. In this case we start
+	  // with an initial bucket size of 11.
+	  double __min_bkts
+	    = std::max<std::size_t>(__n_elt + __n_ins, _M_next_resize ? 0 : 11)
+	      / (double)_M_max_load_factor;
+	  if (__min_bkts >= __n_bkt)
+	    return { true,
+	      _M_next_bkt(std::max<std::size_t>(__builtin_floor(__min_bkts) + 1,
+						__n_bkt * _S_growth_factor)) };
+
+	  _M_next_resize
+	    = __builtin_floor(__n_bkt * (double)_M_max_load_factor);
+	  return { false, 0 };
+	}
+      else
+	return { false, 0 };
+    }
+
+    typedef std::size_t _State;
+
+    _State
+    _M_state() const noexcept
+    { return _M_next_resize; }
+
+    void
+    _M_reset() noexcept
+    { _M_next_resize = 0; }
+
+    void
+    _M_reset(_State __state) noexcept
+    { _M_next_resize = __state; }
+
+    static const std::size_t _S_growth_factor = 2;
+
+    float	_M_max_load_factor;
+    std::size_t	_M_next_resize;
+  };
+
+  // Base classes for std::_Hashtable.  We define these base classes
+  // because in some cases we want to do different things depending on
+  // the value of a policy class.  In some cases the policy class
+  // affects which member functions and nested typedefs are defined;
+  // we handle that by specializing base class templates.  Several of
+  // the base class templates need to access other members of class
+  // template _Hashtable, so we use a variant of the "Curiously
+  // Recurring Template Pattern" (CRTP) technique.
+
+  /**
+   *  Primary class template _Map_base.
+   *
+   *  If the hashtable has a value type of the form pair<const T1, T2> and
+   *  a key extraction policy (_ExtractKey) that returns the first part
+   *  of the pair, the hashtable gets a mapped_type typedef.  If it
+   *  satisfies those criteria and also has unique keys, then it also
+   *  gets an operator[].
+   */
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits,
+	   bool _Unique_keys = _Traits::__unique_keys::value>
+    struct _Map_base { };
+
+  /// Partial specialization, __unique_keys set to false, std::pair value type.
+  template<typename _Key, typename _Val, typename _Alloc, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    struct _Map_base<_Key, pair<const _Key, _Val>, _Alloc, _Select1st, _Equal,
+		     _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits, false>
+    {
+      using mapped_type = _Val;
+    };
+
+  /// Partial specialization, __unique_keys set to true.
+  template<typename _Key, typename _Val, typename _Alloc, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    struct _Map_base<_Key, pair<const _Key, _Val>, _Alloc, _Select1st, _Equal,
+		     _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits, true>
+    {
+    private:
+      using __hashtable_base = _Hashtable_base<_Key, pair<const _Key, _Val>,
+					       _Select1st, _Equal, _Hash,
+					       _RangeHash, _Unused,
+					       _Traits>;
+
+      using __hashtable = _Hashtable<_Key, pair<const _Key, _Val>, _Alloc,
+				     _Select1st, _Equal, _Hash, _RangeHash,
+				     _Unused, _RehashPolicy, _Traits>;
+
+      using __hash_code = typename __hashtable_base::__hash_code;
+
+    public:
+      using key_type = typename __hashtable_base::key_type;
+      using mapped_type = _Val;
+
+      mapped_type&
+      operator[](const key_type& __k);
+
+      mapped_type&
+      operator[](key_type&& __k);
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // DR 761. unordered_map needs an at() member function.
+      mapped_type&
+      at(const key_type& __k)
+      {
+	auto __ite = static_cast<__hashtable*>(this)->find(__k);
+	if (!__ite._M_cur)
+	  __throw_out_of_range(__N("unordered_map::at"));
+	return __ite->second;
+      }
+
+      const mapped_type&
+      at(const key_type& __k) const
+      {
+	auto __ite = static_cast<const __hashtable*>(this)->find(__k);
+	if (!__ite._M_cur)
+	  __throw_out_of_range(__N("unordered_map::at"));
+	return __ite->second;
+      }
+    };
+
+  template<typename _Key, typename _Val, typename _Alloc, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    auto
+    _Map_base<_Key, pair<const _Key, _Val>, _Alloc, _Select1st, _Equal,
+	      _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits, true>::
+    operator[](const key_type& __k)
+    -> mapped_type&
+    {
+      __hashtable* __h = static_cast<__hashtable*>(this);
+      __hash_code __code = __h->_M_hash_code(__k);
+      std::size_t __bkt = __h->_M_bucket_index(__code);
+      if (auto __node = __h->_M_find_node(__bkt, __k, __code))
+	return __node->_M_v().second;
+
+      typename __hashtable::_Scoped_node __node {
+	__h,
+	std::piecewise_construct,
+	std::tuple<const key_type&>(__k),
+	std::tuple<>()
+      };
+      auto __pos
+	= __h->_M_insert_unique_node(__bkt, __code, __node._M_node);
+      __node._M_node = nullptr;
+      return __pos->second;
+    }
+
+  template<typename _Key, typename _Val, typename _Alloc, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    auto
+    _Map_base<_Key, pair<const _Key, _Val>, _Alloc, _Select1st, _Equal,
+	      _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits, true>::
+    operator[](key_type&& __k)
+    -> mapped_type&
+    {
+      __hashtable* __h = static_cast<__hashtable*>(this);
+      __hash_code __code = __h->_M_hash_code(__k);
+      std::size_t __bkt = __h->_M_bucket_index(__code);
+      if (auto __node = __h->_M_find_node(__bkt, __k, __code))
+	return __node->_M_v().second;
+
+      typename __hashtable::_Scoped_node __node {
+	__h,
+	std::piecewise_construct,
+	std::forward_as_tuple(std::move(__k)),
+	std::tuple<>()
+      };
+      auto __pos
+	= __h->_M_insert_unique_node(__bkt, __code, __node._M_node);
+      __node._M_node = nullptr;
+      return __pos->second;
+    }
+
+  // Partial specialization for unordered_map<const T, U>, see PR 104174.
+  template<typename _Key, typename _Val, typename _Alloc, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits, bool __uniq>
+    struct _Map_base<const _Key, pair<const _Key, _Val>,
+		     _Alloc, _Select1st, _Equal, _Hash,
+		     _RangeHash, _Unused, _RehashPolicy, _Traits, __uniq>
+    : _Map_base<_Key, pair<const _Key, _Val>, _Alloc, _Select1st, _Equal, _Hash,
+		_RangeHash, _Unused, _RehashPolicy, _Traits, __uniq>
+    { };
+
+  /**
+   *  Primary class template _Insert_base.
+   *
+   *  Defines @c insert member functions appropriate to all _Hashtables.
+   */
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    struct _Insert_base
+    {
+    protected:
+      using __hashtable_base = _Hashtable_base<_Key, _Value, _ExtractKey,
+					       _Equal, _Hash, _RangeHash,
+					       _Unused, _Traits>;
+
+      using __hashtable = _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+				     _Hash, _RangeHash,
+				     _Unused, _RehashPolicy, _Traits>;
+
+      using __hash_cached = typename _Traits::__hash_cached;
+      using __constant_iterators = typename _Traits::__constant_iterators;
+
+      using __hashtable_alloc = _Hashtable_alloc<
+	__alloc_rebind<_Alloc, _Hash_node<_Value,
+					  __hash_cached::value>>>;
+
+      using value_type = typename __hashtable_base::value_type;
+      using size_type = typename __hashtable_base::size_type;
+
+      using __unique_keys = typename _Traits::__unique_keys;
+      using __node_alloc_type = typename __hashtable_alloc::__node_alloc_type;
+      using __node_gen_type = _AllocNode<__node_alloc_type>;
+
+      __hashtable&
+      _M_conjure_hashtable()
+      { return *(static_cast<__hashtable*>(this)); }
+
+      template<typename _InputIterator, typename _NodeGetter>
+	void
+	_M_insert_range(_InputIterator __first, _InputIterator __last,
+			const _NodeGetter&, true_type __uks);
+
+      template<typename _InputIterator, typename _NodeGetter>
+	void
+	_M_insert_range(_InputIterator __first, _InputIterator __last,
+			const _NodeGetter&, false_type __uks);
+
+    public:
+      using iterator = _Node_iterator<_Value, __constant_iterators::value,
+				      __hash_cached::value>;
+
+      using const_iterator = _Node_const_iterator<_Value,
+						  __constant_iterators::value,
+						  __hash_cached::value>;
+
+      using __ireturn_type = __conditional_t<__unique_keys::value,
+					     std::pair<iterator, bool>,
+					     iterator>;
+
+      __ireturn_type
+      insert(const value_type& __v)
+      {
+	__hashtable& __h = _M_conjure_hashtable();
+	__node_gen_type __node_gen(__h);
+	return __h._M_insert(__v, __node_gen, __unique_keys{});
+      }
+
+      iterator
+      insert(const_iterator __hint, const value_type& __v)
+      {
+	__hashtable& __h = _M_conjure_hashtable();
+	__node_gen_type __node_gen(__h);	
+	return __h._M_insert(__hint, __v, __node_gen, __unique_keys{});
+      }
+
+      template<typename _KType, typename... _Args>
+	std::pair<iterator, bool>
+	try_emplace(const_iterator, _KType&& __k, _Args&&... __args)
+	{
+	  __hashtable& __h = _M_conjure_hashtable();
+	  auto __code = __h._M_hash_code(__k);
+	  std::size_t __bkt = __h._M_bucket_index(__code);
+	  if (auto __node = __h._M_find_node(__bkt, __k, __code))
+	    return { iterator(__node), false };
+
+	  typename __hashtable::_Scoped_node __node {
+	    &__h,
+	    std::piecewise_construct,
+	    std::forward_as_tuple(std::forward<_KType>(__k)),
+	    std::forward_as_tuple(std::forward<_Args>(__args)...)
+	    };
+	  auto __it
+	    = __h._M_insert_unique_node(__bkt, __code, __node._M_node);
+	  __node._M_node = nullptr;
+	  return { __it, true };
+	}
+
+      void
+      insert(initializer_list<value_type> __l)
+      { this->insert(__l.begin(), __l.end()); }
+
+      template<typename _InputIterator>
+	void
+	insert(_InputIterator __first, _InputIterator __last)
+	{
+	  __hashtable& __h = _M_conjure_hashtable();
+	  __node_gen_type __node_gen(__h);
+	  return _M_insert_range(__first, __last, __node_gen, __unique_keys{});
+	}
+    };
+
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    template<typename _InputIterator, typename _NodeGetter>
+      void
+      _Insert_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+		   _Hash, _RangeHash, _Unused,
+		   _RehashPolicy, _Traits>::
+      _M_insert_range(_InputIterator __first, _InputIterator __last,
+		      const _NodeGetter& __node_gen, true_type __uks)
+      {
+	__hashtable& __h = _M_conjure_hashtable();
+	for (; __first != __last; ++__first)
+	  __h._M_insert(*__first, __node_gen, __uks);
+      }
+
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    template<typename _InputIterator, typename _NodeGetter>
+      void
+      _Insert_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+		   _Hash, _RangeHash, _Unused,
+		   _RehashPolicy, _Traits>::
+      _M_insert_range(_InputIterator __first, _InputIterator __last,
+		      const _NodeGetter& __node_gen, false_type __uks)
+      {
+	using __rehash_type = typename __hashtable::__rehash_type;
+	using __rehash_state = typename __hashtable::__rehash_state;
+	using pair_type = std::pair<bool, std::size_t>;
+
+	size_type __n_elt = __detail::__distance_fw(__first, __last);
+	if (__n_elt == 0)
+	  return;
+
+	__hashtable& __h = _M_conjure_hashtable();
+	__rehash_type& __rehash = __h._M_rehash_policy;
+	const __rehash_state& __saved_state = __rehash._M_state();
+	pair_type __do_rehash = __rehash._M_need_rehash(__h._M_bucket_count,
+							__h._M_element_count,
+							__n_elt);
+
+	if (__do_rehash.first)
+	  __h._M_rehash(__do_rehash.second, __saved_state);
+
+	for (; __first != __last; ++__first)
+	  __h._M_insert(*__first, __node_gen, __uks);
+      }
+
+  /**
+   *  Primary class template _Insert.
+   *
+   *  Defines @c insert member functions that depend on _Hashtable policies,
+   *  via partial specializations.
+   */
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits,
+	   bool _Constant_iterators = _Traits::__constant_iterators::value>
+    struct _Insert;
+
+  /// Specialization.
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    struct _Insert<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+		   _Hash, _RangeHash, _Unused,
+		   _RehashPolicy, _Traits, true>
+    : public _Insert_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+			  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>
+    {
+      using __base_type = _Insert_base<_Key, _Value, _Alloc, _ExtractKey,
+				       _Equal, _Hash, _RangeHash, _Unused,
+				       _RehashPolicy, _Traits>;
+
+      using value_type = typename __base_type::value_type;
+      using iterator = typename __base_type::iterator;
+      using const_iterator =  typename __base_type::const_iterator;
+      using __ireturn_type = typename __base_type::__ireturn_type;
+
+      using __unique_keys = typename __base_type::__unique_keys;
+      using __hashtable = typename __base_type::__hashtable;
+      using __node_gen_type = typename __base_type::__node_gen_type;
+
+      using __base_type::insert;
+
+      __ireturn_type
+      insert(value_type&& __v)
+      {
+	__hashtable& __h = this->_M_conjure_hashtable();
+	__node_gen_type __node_gen(__h);
+	return __h._M_insert(std::move(__v), __node_gen, __unique_keys{});
+      }
+
+      iterator
+      insert(const_iterator __hint, value_type&& __v)
+      {
+	__hashtable& __h = this->_M_conjure_hashtable();
+	__node_gen_type __node_gen(__h);
+	return __h._M_insert(__hint, std::move(__v), __node_gen,
+			     __unique_keys{});
+      }
+    };
+
+  /// Specialization.
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    struct _Insert<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+		   _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits, false>
+    : public _Insert_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+			  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>
+    {
+      using __base_type = _Insert_base<_Key, _Value, _Alloc, _ExtractKey,
+				       _Equal, _Hash, _RangeHash, _Unused,
+				       _RehashPolicy, _Traits>;
+      using value_type = typename __base_type::value_type;
+      using iterator = typename __base_type::iterator;
+      using const_iterator =  typename __base_type::const_iterator;
+
+      using __unique_keys = typename __base_type::__unique_keys;
+      using __hashtable = typename __base_type::__hashtable;
+      using __ireturn_type = typename __base_type::__ireturn_type;
+
+      using __base_type::insert;
+
+      template<typename _Pair>
+	using __is_cons = std::is_constructible<value_type, _Pair&&>;
+
+      template<typename _Pair>
+	using _IFcons = std::enable_if<__is_cons<_Pair>::value>;
+
+      template<typename _Pair>
+	using _IFconsp = typename _IFcons<_Pair>::type;
+
+      template<typename _Pair, typename = _IFconsp<_Pair>>
+	__ireturn_type
+	insert(_Pair&& __v)
+	{
+	  __hashtable& __h = this->_M_conjure_hashtable();
+	  return __h._M_emplace(__unique_keys{}, std::forward<_Pair>(__v));
+	}
+
+      template<typename _Pair, typename = _IFconsp<_Pair>>
+	iterator
+	insert(const_iterator __hint, _Pair&& __v)
+	{
+	  __hashtable& __h = this->_M_conjure_hashtable();
+	  return __h._M_emplace(__hint, __unique_keys{},
+				std::forward<_Pair>(__v));
+	}
+   };
+
+  template<typename _Policy>
+    using __has_load_factor = typename _Policy::__has_load_factor;
+
+  /**
+   *  Primary class template  _Rehash_base.
+   *
+   *  Give hashtable the max_load_factor functions and reserve iff the
+   *  rehash policy supports it.
+  */
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits,
+	   typename =
+	     __detected_or_t<false_type, __has_load_factor, _RehashPolicy>>
+    struct _Rehash_base;
+
+  /// Specialization when rehash policy doesn't provide load factor management.
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    struct _Rehash_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+			_Hash, _RangeHash, _Unused, _RehashPolicy, _Traits,
+			false_type /* Has load factor */>
+    {
+    };
+
+  /// Specialization when rehash policy provide load factor management.
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    struct _Rehash_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+			_Hash, _RangeHash, _Unused, _RehashPolicy, _Traits,
+			true_type /* Has load factor */>
+    {
+    private:
+      using __hashtable = _Hashtable<_Key, _Value, _Alloc, _ExtractKey,
+				     _Equal, _Hash, _RangeHash, _Unused,
+				     _RehashPolicy, _Traits>;
+
+    public:
+      float
+      max_load_factor() const noexcept
+      {
+	const __hashtable* __this = static_cast<const __hashtable*>(this);
+	return __this->__rehash_policy().max_load_factor();
+      }
+
+      void
+      max_load_factor(float __z)
+      {
+	__hashtable* __this = static_cast<__hashtable*>(this);
+	__this->__rehash_policy(_RehashPolicy(__z));
+      }
+
+      void
+      reserve(std::size_t __n)
+      {
+	__hashtable* __this = static_cast<__hashtable*>(this);
+	__this->rehash(__this->__rehash_policy()._M_bkt_for_elements(__n));
+      }
+    };
+
+  /**
+   *  Primary class template _Hashtable_ebo_helper.
+   *
+   *  Helper class using EBO when it is not forbidden (the type is not
+   *  final) and when it is worth it (the type is empty.)
+   */
+  template<int _Nm, typename _Tp,
+	   bool __use_ebo = !__is_final(_Tp) && __is_empty(_Tp)>
+    struct _Hashtable_ebo_helper;
+
+  /// Specialization using EBO.
+  template<int _Nm, typename _Tp>
+    struct _Hashtable_ebo_helper<_Nm, _Tp, true>
+    : private _Tp
+    {
+      _Hashtable_ebo_helper() noexcept(noexcept(_Tp())) : _Tp() { }
+
+      template<typename _OtherTp>
+	_Hashtable_ebo_helper(_OtherTp&& __tp)
+	: _Tp(std::forward<_OtherTp>(__tp))
+	{ }
+
+      const _Tp& _M_cget() const { return static_cast<const _Tp&>(*this); }
+      _Tp& _M_get() { return static_cast<_Tp&>(*this); }
+    };
+
+  /// Specialization not using EBO.
+  template<int _Nm, typename _Tp>
+    struct _Hashtable_ebo_helper<_Nm, _Tp, false>
+    {
+      _Hashtable_ebo_helper() = default;
+
+      template<typename _OtherTp>
+	_Hashtable_ebo_helper(_OtherTp&& __tp)
+	: _M_tp(std::forward<_OtherTp>(__tp))
+	{ }
+
+      const _Tp& _M_cget() const { return _M_tp; }
+      _Tp& _M_get() { return _M_tp; }
+
+    private:
+      _Tp _M_tp{};
+    };
+
+  /**
+   *  Primary class template _Local_iterator_base.
+   *
+   *  Base class for local iterators, used to iterate within a bucket
+   *  but not between buckets.
+   */
+  template<typename _Key, typename _Value, typename _ExtractKey,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   bool __cache_hash_code>
+    struct _Local_iterator_base;
+
+  /**
+   *  Primary class template _Hash_code_base.
+   *
+   *  Encapsulates two policy issues that aren't quite orthogonal.
+   *   (1) the difference between using a ranged hash function and using
+   *       the combination of a hash function and a range-hashing function.
+   *       In the former case we don't have such things as hash codes, so
+   *       we have a dummy type as placeholder.
+   *   (2) Whether or not we cache hash codes.  Caching hash codes is
+   *       meaningless if we have a ranged hash function.
+   *
+   *  We also put the key extraction objects here, for convenience.
+   *  Each specialization derives from one or more of the template
+   *  parameters to benefit from Ebo. This is important as this type
+   *  is inherited in some cases by the _Local_iterator_base type used
+   *  to implement local_iterator and const_local_iterator. As with
+   *  any iterator type we prefer to make it as small as possible.
+   */
+  template<typename _Key, typename _Value, typename _ExtractKey,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   bool __cache_hash_code>
+    struct _Hash_code_base
+    : private _Hashtable_ebo_helper<1, _Hash>
+    {
+    private:
+      using __ebo_hash = _Hashtable_ebo_helper<1, _Hash>;
+
+      // Gives the local iterator implementation access to _M_bucket_index().
+      friend struct _Local_iterator_base<_Key, _Value, _ExtractKey,
+					 _Hash, _RangeHash, _Unused, false>;
+
+    public:
+      typedef _Hash					hasher;
+
+      hasher
+      hash_function() const
+      { return _M_hash(); }
+
+    protected:
+      typedef std::size_t 				__hash_code;
+
+      // We need the default constructor for the local iterators and _Hashtable
+      // default constructor.
+      _Hash_code_base() = default;
+
+      _Hash_code_base(const _Hash& __hash) : __ebo_hash(__hash) { }
+
+      __hash_code
+      _M_hash_code(const _Key& __k) const
+      {
+	static_assert(__is_invocable<const _Hash&, const _Key&>{},
+	    "hash function must be invocable with an argument of key type");
+	return _M_hash()(__k);
+      }
+
+      template<typename _Kt>
+	__hash_code
+	_M_hash_code_tr(const _Kt& __k) const
+	{
+	  static_assert(__is_invocable<const _Hash&, const _Kt&>{},
+	    "hash function must be invocable with an argument of key type");
+	  return _M_hash()(__k);
+	}
+
+      __hash_code
+      _M_hash_code(const _Hash&,
+		   const _Hash_node_value<_Value, true>& __n) const
+      { return __n._M_hash_code; }
+
+      // Compute hash code using _Hash as __n _M_hash_code, if present, was
+      // computed using _H2.
+      template<typename _H2>
+	__hash_code
+	_M_hash_code(const _H2&,
+		const _Hash_node_value<_Value, __cache_hash_code>& __n) const
+	{ return _M_hash_code(_ExtractKey{}(__n._M_v())); }
+
+      __hash_code
+      _M_hash_code(const _Hash_node_value<_Value, false>& __n) const
+      { return _M_hash_code(_ExtractKey{}(__n._M_v())); }
+
+      __hash_code
+      _M_hash_code(const _Hash_node_value<_Value, true>& __n) const
+      { return __n._M_hash_code; }
+
+      std::size_t
+      _M_bucket_index(__hash_code __c, std::size_t __bkt_count) const
+      { return _RangeHash{}(__c, __bkt_count); }
+
+      std::size_t
+      _M_bucket_index(const _Hash_node_value<_Value, false>& __n,
+		      std::size_t __bkt_count) const
+	noexcept( noexcept(declval<const _Hash&>()(declval<const _Key&>()))
+		  && noexcept(declval<const _RangeHash&>()((__hash_code)0,
+							   (std::size_t)0)) )
+      {
+	return _RangeHash{}(_M_hash_code(_ExtractKey{}(__n._M_v())),
+			    __bkt_count);
+      }
+
+      std::size_t
+      _M_bucket_index(const _Hash_node_value<_Value, true>& __n,
+		      std::size_t __bkt_count) const
+	noexcept( noexcept(declval<const _RangeHash&>()((__hash_code)0,
+							(std::size_t)0)) )
+      { return _RangeHash{}(__n._M_hash_code, __bkt_count); }
+
+      void
+      _M_store_code(_Hash_node_code_cache<false>&, __hash_code) const
+      { }
+
+      void
+      _M_copy_code(_Hash_node_code_cache<false>&,
+		   const _Hash_node_code_cache<false>&) const
+      { }
+
+      void
+      _M_store_code(_Hash_node_code_cache<true>& __n, __hash_code __c) const
+      { __n._M_hash_code = __c; }
+
+      void
+      _M_copy_code(_Hash_node_code_cache<true>& __to,
+		   const _Hash_node_code_cache<true>& __from) const
+      { __to._M_hash_code = __from._M_hash_code; }
+
+      void
+      _M_swap(_Hash_code_base& __x)
+      { std::swap(__ebo_hash::_M_get(), __x.__ebo_hash::_M_get()); }
+
+      const _Hash&
+      _M_hash() const { return __ebo_hash::_M_cget(); }
+    };
+
+  /// Partial specialization used when nodes contain a cached hash code.
+  template<typename _Key, typename _Value, typename _ExtractKey,
+	   typename _Hash, typename _RangeHash, typename _Unused>
+    struct _Local_iterator_base<_Key, _Value, _ExtractKey,
+				_Hash, _RangeHash, _Unused, true>
+    : public _Node_iterator_base<_Value, true>
+    {
+    protected:
+      using __base_node_iter = _Node_iterator_base<_Value, true>;
+      using __hash_code_base = _Hash_code_base<_Key, _Value, _ExtractKey,
+					      _Hash, _RangeHash, _Unused, true>;
+
+      _Local_iterator_base() = default;
+      _Local_iterator_base(const __hash_code_base&,
+			   _Hash_node<_Value, true>* __p,
+			   std::size_t __bkt, std::size_t __bkt_count)
+      : __base_node_iter(__p), _M_bucket(__bkt), _M_bucket_count(__bkt_count)
+      { }
+
+      void
+      _M_incr()
+      {
+	__base_node_iter::_M_incr();
+	if (this->_M_cur)
+	  {
+	    std::size_t __bkt
+	      = _RangeHash{}(this->_M_cur->_M_hash_code, _M_bucket_count);
+	    if (__bkt != _M_bucket)
+	      this->_M_cur = nullptr;
+	  }
+      }
+
+      std::size_t _M_bucket;
+      std::size_t _M_bucket_count;
+
+    public:
+      std::size_t
+      _M_get_bucket() const { return _M_bucket; }  // for debug mode
+    };
+
+  // Uninitialized storage for a _Hash_code_base.
+  // This type is DefaultConstructible and Assignable even if the
+  // _Hash_code_base type isn't, so that _Local_iterator_base<..., false>
+  // can be DefaultConstructible and Assignable.
+  template<typename _Tp, bool _IsEmpty = std::is_empty<_Tp>::value>
+    struct _Hash_code_storage
+    {
+      __gnu_cxx::__aligned_buffer<_Tp> _M_storage;
+
+      _Tp*
+      _M_h() { return _M_storage._M_ptr(); }
+
+      const _Tp*
+      _M_h() const { return _M_storage._M_ptr(); }
+    };
+
+  // Empty partial specialization for empty _Hash_code_base types.
+  template<typename _Tp>
+    struct _Hash_code_storage<_Tp, true>
+    {
+      static_assert( std::is_empty<_Tp>::value, "Type must be empty" );
+
+      // As _Tp is an empty type there will be no bytes written/read through
+      // the cast pointer, so no strict-aliasing violation.
+      _Tp*
+      _M_h() { return reinterpret_cast<_Tp*>(this); }
+
+      const _Tp*
+      _M_h() const { return reinterpret_cast<const _Tp*>(this); }
+    };
+
+  template<typename _Key, typename _Value, typename _ExtractKey,
+	   typename _Hash, typename _RangeHash, typename _Unused>
+    using __hash_code_for_local_iter
+      = _Hash_code_storage<_Hash_code_base<_Key, _Value, _ExtractKey,
+					   _Hash, _RangeHash, _Unused, false>>;
+
+  // Partial specialization used when hash codes are not cached
+  template<typename _Key, typename _Value, typename _ExtractKey,
+	   typename _Hash, typename _RangeHash, typename _Unused>
+    struct _Local_iterator_base<_Key, _Value, _ExtractKey,
+				_Hash, _RangeHash, _Unused, false>
+    : __hash_code_for_local_iter<_Key, _Value, _ExtractKey, _Hash, _RangeHash,
+				 _Unused>
+    , _Node_iterator_base<_Value, false>
+    {
+    protected:
+      using __hash_code_base = _Hash_code_base<_Key, _Value, _ExtractKey,
+					     _Hash, _RangeHash, _Unused, false>;
+      using __node_iter_base = _Node_iterator_base<_Value, false>;
+
+      _Local_iterator_base() : _M_bucket_count(-1) { }
+
+      _Local_iterator_base(const __hash_code_base& __base,
+			   _Hash_node<_Value, false>* __p,
+			   std::size_t __bkt, std::size_t __bkt_count)
+      : __node_iter_base(__p), _M_bucket(__bkt), _M_bucket_count(__bkt_count)
+      { _M_init(__base); }
+
+      ~_Local_iterator_base()
+      {
+	if (_M_bucket_count != size_t(-1))
+	  _M_destroy();
+      }
+
+      _Local_iterator_base(const _Local_iterator_base& __iter)
+      : __node_iter_base(__iter._M_cur), _M_bucket(__iter._M_bucket)
+      , _M_bucket_count(__iter._M_bucket_count)
+      {
+	if (_M_bucket_count != size_t(-1))
+	  _M_init(*__iter._M_h());
+      }
+
+      _Local_iterator_base&
+      operator=(const _Local_iterator_base& __iter)
+      {
+	if (_M_bucket_count != -1)
+	  _M_destroy();
+	this->_M_cur = __iter._M_cur;
+	_M_bucket = __iter._M_bucket;
+	_M_bucket_count = __iter._M_bucket_count;
+	if (_M_bucket_count != -1)
+	  _M_init(*__iter._M_h());
+	return *this;
+      }
+
+      void
+      _M_incr()
+      {
+	__node_iter_base::_M_incr();
+	if (this->_M_cur)
+	  {
+	    std::size_t __bkt = this->_M_h()->_M_bucket_index(*this->_M_cur,
+							      _M_bucket_count);
+	    if (__bkt != _M_bucket)
+	      this->_M_cur = nullptr;
+	  }
+      }
+
+      std::size_t _M_bucket;
+      std::size_t _M_bucket_count;
+
+      void
+      _M_init(const __hash_code_base& __base)
+      { ::new(this->_M_h()) __hash_code_base(__base); }
+
+      void
+      _M_destroy() { this->_M_h()->~__hash_code_base(); }
+
+    public:
+      std::size_t
+      _M_get_bucket() const { return _M_bucket; }  // for debug mode
+    };
+
+  /// local iterators
+  template<typename _Key, typename _Value, typename _ExtractKey,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   bool __constant_iterators, bool __cache>
+    struct _Local_iterator
+    : public _Local_iterator_base<_Key, _Value, _ExtractKey,
+				  _Hash, _RangeHash, _Unused, __cache>
+    {
+    private:
+      using __base_type = _Local_iterator_base<_Key, _Value, _ExtractKey,
+					   _Hash, _RangeHash, _Unused, __cache>;
+      using __hash_code_base = typename __base_type::__hash_code_base;
+
+    public:
+      using value_type = _Value;
+      using pointer = __conditional_t<__constant_iterators,
+				      const value_type*, value_type*>;
+      using reference = __conditional_t<__constant_iterators,
+					const value_type&, value_type&>;
+      using difference_type = ptrdiff_t;
+      using iterator_category = forward_iterator_tag;
+
+      _Local_iterator() = default;
+
+      _Local_iterator(const __hash_code_base& __base,
+		      _Hash_node<_Value, __cache>* __n,
+		      std::size_t __bkt, std::size_t __bkt_count)
+      : __base_type(__base, __n, __bkt, __bkt_count)
+      { }
+
+      reference
+      operator*() const
+      { return this->_M_cur->_M_v(); }
+
+      pointer
+      operator->() const
+      { return this->_M_cur->_M_valptr(); }
+
+      _Local_iterator&
+      operator++()
+      {
+	this->_M_incr();
+	return *this;
+      }
+
+      _Local_iterator
+      operator++(int)
+      {
+	_Local_iterator __tmp(*this);
+	this->_M_incr();
+	return __tmp;
+      }
+    };
+
+  /// local const_iterators
+  template<typename _Key, typename _Value, typename _ExtractKey,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   bool __constant_iterators, bool __cache>
+    struct _Local_const_iterator
+    : public _Local_iterator_base<_Key, _Value, _ExtractKey,
+				  _Hash, _RangeHash, _Unused, __cache>
+    {
+    private:
+      using __base_type = _Local_iterator_base<_Key, _Value, _ExtractKey,
+					   _Hash, _RangeHash, _Unused, __cache>;
+      using __hash_code_base = typename __base_type::__hash_code_base;
+
+    public:
+      typedef _Value					value_type;
+      typedef const value_type*				pointer;
+      typedef const value_type&				reference;
+      typedef std::ptrdiff_t				difference_type;
+      typedef std::forward_iterator_tag			iterator_category;
+
+      _Local_const_iterator() = default;
+
+      _Local_const_iterator(const __hash_code_base& __base,
+			    _Hash_node<_Value, __cache>* __n,
+			    std::size_t __bkt, std::size_t __bkt_count)
+      : __base_type(__base, __n, __bkt, __bkt_count)
+      { }
+
+      _Local_const_iterator(const _Local_iterator<_Key, _Value, _ExtractKey,
+						  _Hash, _RangeHash, _Unused,
+						  __constant_iterators,
+						  __cache>& __x)
+      : __base_type(__x)
+      { }
+
+      reference
+      operator*() const
+      { return this->_M_cur->_M_v(); }
+
+      pointer
+      operator->() const
+      { return this->_M_cur->_M_valptr(); }
+
+      _Local_const_iterator&
+      operator++()
+      {
+	this->_M_incr();
+	return *this;
+      }
+
+      _Local_const_iterator
+      operator++(int)
+      {
+	_Local_const_iterator __tmp(*this);
+	this->_M_incr();
+	return __tmp;
+      }
+    };
+
+  /**
+   *  Primary class template _Hashtable_base.
+   *
+   *  Helper class adding management of _Equal functor to
+   *  _Hash_code_base type.
+   *
+   *  Base class templates are:
+   *    - __detail::_Hash_code_base
+   *    - __detail::_Hashtable_ebo_helper
+   */
+  template<typename _Key, typename _Value, typename _ExtractKey,
+	   typename _Equal, typename _Hash, typename _RangeHash,
+	   typename _Unused, typename _Traits>
+    struct _Hashtable_base
+    : public _Hash_code_base<_Key, _Value, _ExtractKey, _Hash, _RangeHash,
+			     _Unused, _Traits::__hash_cached::value>,
+      private _Hashtable_ebo_helper<0, _Equal>
+    {
+    public:
+      typedef _Key					key_type;
+      typedef _Value					value_type;
+      typedef _Equal					key_equal;
+      typedef std::size_t				size_type;
+      typedef std::ptrdiff_t				difference_type;
+
+      using __traits_type = _Traits;
+      using __hash_cached = typename __traits_type::__hash_cached;
+
+      using __hash_code_base = _Hash_code_base<_Key, _Value, _ExtractKey,
+					       _Hash, _RangeHash, _Unused,
+					       __hash_cached::value>;
+
+      using __hash_code = typename __hash_code_base::__hash_code;
+
+    private:
+      using _EqualEBO = _Hashtable_ebo_helper<0, _Equal>;
+
+      static bool
+      _S_equals(__hash_code, const _Hash_node_code_cache<false>&)
+      { return true; }
+
+      static bool
+      _S_node_equals(const _Hash_node_code_cache<false>&,
+		     const _Hash_node_code_cache<false>&)
+      { return true; }
+
+      static bool
+      _S_equals(__hash_code __c, const _Hash_node_code_cache<true>& __n)
+      { return __c == __n._M_hash_code; }
+
+      static bool
+      _S_node_equals(const _Hash_node_code_cache<true>& __lhn,
+		     const _Hash_node_code_cache<true>& __rhn)
+      { return __lhn._M_hash_code == __rhn._M_hash_code; }
+
+    protected:
+      _Hashtable_base() = default;
+
+      _Hashtable_base(const _Hash& __hash, const _Equal& __eq)
+      : __hash_code_base(__hash), _EqualEBO(__eq)
+      { }
+
+      bool
+      _M_key_equals(const _Key& __k,
+		    const _Hash_node_value<_Value,
+					   __hash_cached::value>& __n) const
+      {
+	static_assert(__is_invocable<const _Equal&, const _Key&, const _Key&>{},
+	  "key equality predicate must be invocable with two arguments of "
+	  "key type");
+	return _M_eq()(__k, _ExtractKey{}(__n._M_v()));
+      }
+
+      template<typename _Kt>
+	bool
+	_M_key_equals_tr(const _Kt& __k,
+			 const _Hash_node_value<_Value,
+					     __hash_cached::value>& __n) const
+	{
+	  static_assert(
+	    __is_invocable<const _Equal&, const _Kt&, const _Key&>{},
+	    "key equality predicate must be invocable with two arguments of "
+	    "key type");
+	  return _M_eq()(__k, _ExtractKey{}(__n._M_v()));
+	}
+
+      bool
+      _M_equals(const _Key& __k, __hash_code __c,
+		const _Hash_node_value<_Value, __hash_cached::value>& __n) const
+      { return _S_equals(__c, __n) && _M_key_equals(__k, __n); }
+
+      template<typename _Kt>
+	bool
+	_M_equals_tr(const _Kt& __k, __hash_code __c,
+		     const _Hash_node_value<_Value,
+					    __hash_cached::value>& __n) const
+	{ return _S_equals(__c, __n) && _M_key_equals_tr(__k, __n); }
+
+      bool
+      _M_node_equals(
+	const _Hash_node_value<_Value, __hash_cached::value>& __lhn,
+	const _Hash_node_value<_Value, __hash_cached::value>& __rhn) const
+      {
+	return _S_node_equals(__lhn, __rhn)
+	  && _M_key_equals(_ExtractKey{}(__lhn._M_v()), __rhn);
+      }
+
+      void
+      _M_swap(_Hashtable_base& __x)
+      {
+	__hash_code_base::_M_swap(__x);
+	std::swap(_EqualEBO::_M_get(), __x._EqualEBO::_M_get());
+      }
+
+      const _Equal&
+      _M_eq() const { return _EqualEBO::_M_cget(); }
+    };
+
+  /**
+   *  Primary class template  _Equality.
+   *
+   *  This is for implementing equality comparison for unordered
+   *  containers, per N3068, by John Lakos and Pablo Halpern.
+   *  Algorithmically, we follow closely the reference implementations
+   *  therein.
+   */
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits,
+	   bool _Unique_keys = _Traits::__unique_keys::value>
+    struct _Equality;
+
+  /// unordered_map and unordered_set specializations.
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    struct _Equality<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+		     _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits, true>
+    {
+      using __hashtable = _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+				     _Hash, _RangeHash, _Unused,
+				     _RehashPolicy, _Traits>;
+
+      bool
+      _M_equal(const __hashtable&) const;
+    };
+
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    bool
+    _Equality<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+	      _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits, true>::
+    _M_equal(const __hashtable& __other) const
+    {
+      using __node_type = typename __hashtable::__node_type;
+      const __hashtable* __this = static_cast<const __hashtable*>(this);
+      if (__this->size() != __other.size())
+	return false;
+
+      for (auto __itx = __this->begin(); __itx != __this->end(); ++__itx)
+	{
+	  std::size_t __ybkt = __other._M_bucket_index(*__itx._M_cur);
+	  auto __prev_n = __other._M_buckets[__ybkt];
+	  if (!__prev_n)
+	    return false;
+
+	  for (__node_type* __n = static_cast<__node_type*>(__prev_n->_M_nxt);;
+	       __n = __n->_M_next())
+	    {
+	      if (__n->_M_v() == *__itx)
+		break;
+
+	      if (!__n->_M_nxt
+		  || __other._M_bucket_index(*__n->_M_next()) != __ybkt)
+		return false;
+	    }
+	}
+
+      return true;
+    }
+
+  /// unordered_multiset and unordered_multimap specializations.
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    struct _Equality<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+		     _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits, false>
+    {
+      using __hashtable = _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+				     _Hash, _RangeHash, _Unused,
+				     _RehashPolicy, _Traits>;
+
+      bool
+      _M_equal(const __hashtable&) const;
+    };
+
+  template<typename _Key, typename _Value, typename _Alloc,
+	   typename _ExtractKey, typename _Equal,
+	   typename _Hash, typename _RangeHash, typename _Unused,
+	   typename _RehashPolicy, typename _Traits>
+    bool
+    _Equality<_Key, _Value, _Alloc, _ExtractKey, _Equal,
+	      _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits, false>::
+    _M_equal(const __hashtable& __other) const
+    {
+      using __node_type = typename __hashtable::__node_type;
+      const __hashtable* __this = static_cast<const __hashtable*>(this);
+      if (__this->size() != __other.size())
+	return false;
+
+      for (auto __itx = __this->begin(); __itx != __this->end();)
+	{
+	  std::size_t __x_count = 1;
+	  auto __itx_end = __itx;
+	  for (++__itx_end; __itx_end != __this->end()
+		 && __this->key_eq()(_ExtractKey{}(*__itx),
+				     _ExtractKey{}(*__itx_end));
+	       ++__itx_end)
+	    ++__x_count;
+
+	  std::size_t __ybkt = __other._M_bucket_index(*__itx._M_cur);
+	  auto __y_prev_n = __other._M_buckets[__ybkt];
+	  if (!__y_prev_n)
+	    return false;
+
+	  __node_type* __y_n = static_cast<__node_type*>(__y_prev_n->_M_nxt);
+	  for (;;)
+	    {
+	      if (__this->key_eq()(_ExtractKey{}(__y_n->_M_v()),
+				   _ExtractKey{}(*__itx)))
+		break;
+
+	      auto __y_ref_n = __y_n;
+	      for (__y_n = __y_n->_M_next(); __y_n; __y_n = __y_n->_M_next())
+		if (!__other._M_node_equals(*__y_ref_n, *__y_n))
+		  break;
+
+	      if (!__y_n || __other._M_bucket_index(*__y_n) != __ybkt)
+		return false;
+	    }
+
+	  typename __hashtable::const_iterator __ity(__y_n);
+	  for (auto __ity_end = __ity; __ity_end != __other.end(); ++__ity_end)
+	    if (--__x_count == 0)
+	      break;
+
+	  if (__x_count != 0)
+	    return false;
+
+	  if (!std::is_permutation(__itx, __itx_end, __ity))
+	    return false;
+
+	  __itx = __itx_end;
+	}
+      return true;
+    }
+
+  /**
+   * This type deals with all allocation and keeps an allocator instance
+   * through inheritance to benefit from EBO when possible.
+   */
+  template<typename _NodeAlloc>
+    struct _Hashtable_alloc : private _Hashtable_ebo_helper<0, _NodeAlloc>
+    {
+    private:
+      using __ebo_node_alloc = _Hashtable_ebo_helper<0, _NodeAlloc>;
+
+      template<typename>
+	struct __get_value_type;
+      template<typename _Val, bool _Cache_hash_code>
+	struct __get_value_type<_Hash_node<_Val, _Cache_hash_code>>
+	{ using type = _Val; };
+
+    public:
+      using __node_type = typename _NodeAlloc::value_type;
+      using __node_alloc_type = _NodeAlloc;
+      // Use __gnu_cxx to benefit from _S_always_equal and al.
+      using __node_alloc_traits = __gnu_cxx::__alloc_traits<__node_alloc_type>;
+
+      using __value_alloc_traits = typename __node_alloc_traits::template
+	rebind_traits<typename __get_value_type<__node_type>::type>;
+
+      using __node_ptr = __node_type*;
+      using __node_base = _Hash_node_base;
+      using __node_base_ptr = __node_base*;
+      using __buckets_alloc_type =
+	__alloc_rebind<__node_alloc_type, __node_base_ptr>;
+      using __buckets_alloc_traits = std::allocator_traits<__buckets_alloc_type>;
+      using __buckets_ptr = __node_base_ptr*;
+
+      _Hashtable_alloc() = default;
+      _Hashtable_alloc(const _Hashtable_alloc&) = default;
+      _Hashtable_alloc(_Hashtable_alloc&&) = default;
+
+      template<typename _Alloc>
+	_Hashtable_alloc(_Alloc&& __a)
+	: __ebo_node_alloc(std::forward<_Alloc>(__a))
+	{ }
+
+      __node_alloc_type&
+      _M_node_allocator()
+      { return __ebo_node_alloc::_M_get(); }
+
+      const __node_alloc_type&
+      _M_node_allocator() const
+      { return __ebo_node_alloc::_M_cget(); }
+
+      // Allocate a node and construct an element within it.
+      template<typename... _Args>
+	__node_ptr
+	_M_allocate_node(_Args&&... __args);
+
+      // Destroy the element within a node and deallocate the node.
+      void
+      _M_deallocate_node(__node_ptr __n);
+
+      // Deallocate a node.
+      void
+      _M_deallocate_node_ptr(__node_ptr __n);
+
+      // Deallocate the linked list of nodes pointed to by __n.
+      // The elements within the nodes are destroyed.
+      void
+      _M_deallocate_nodes(__node_ptr __n);
+
+      __buckets_ptr
+      _M_allocate_buckets(std::size_t __bkt_count);
+
+      void
+      _M_deallocate_buckets(__buckets_ptr, std::size_t __bkt_count);
+    };
+
+  // Definitions of class template _Hashtable_alloc's out-of-line member
+  // functions.
+  template<typename _NodeAlloc>
+    template<typename... _Args>
+      auto
+      _Hashtable_alloc<_NodeAlloc>::_M_allocate_node(_Args&&... __args)
+      -> __node_ptr
+      {
+	auto __nptr = __node_alloc_traits::allocate(_M_node_allocator(), 1);
+	__node_ptr __n = std::__to_address(__nptr);
+	__try
+	  {
+	    ::new ((void*)__n) __node_type;
+	    __node_alloc_traits::construct(_M_node_allocator(),
+					   __n->_M_valptr(),
+					   std::forward<_Args>(__args)...);
+	    return __n;
+	  }
+	__catch(...)
+	  {
+	    __node_alloc_traits::deallocate(_M_node_allocator(), __nptr, 1);
+	    __throw_exception_again;
+	  }
+      }
+
+  template<typename _NodeAlloc>
+    void
+    _Hashtable_alloc<_NodeAlloc>::_M_deallocate_node(__node_ptr __n)
+    {
+      __node_alloc_traits::destroy(_M_node_allocator(), __n->_M_valptr());
+      _M_deallocate_node_ptr(__n);
+    }
+
+  template<typename _NodeAlloc>
+    void
+    _Hashtable_alloc<_NodeAlloc>::_M_deallocate_node_ptr(__node_ptr __n)
+    {
+      typedef typename __node_alloc_traits::pointer _Ptr;
+      auto __ptr = std::pointer_traits<_Ptr>::pointer_to(*__n);
+      __n->~__node_type();
+      __node_alloc_traits::deallocate(_M_node_allocator(), __ptr, 1);
+    }
+
+  template<typename _NodeAlloc>
+    void
+    _Hashtable_alloc<_NodeAlloc>::_M_deallocate_nodes(__node_ptr __n)
+    {
+      while (__n)
+	{
+	  __node_ptr __tmp = __n;
+	  __n = __n->_M_next();
+	  _M_deallocate_node(__tmp);
+	}
+    }
+
+  template<typename _NodeAlloc>
+    auto
+    _Hashtable_alloc<_NodeAlloc>::_M_allocate_buckets(std::size_t __bkt_count)
+    -> __buckets_ptr
+    {
+      __buckets_alloc_type __alloc(_M_node_allocator());
+
+      auto __ptr = __buckets_alloc_traits::allocate(__alloc, __bkt_count);
+      __buckets_ptr __p = std::__to_address(__ptr);
+      __builtin_memset(__p, 0, __bkt_count * sizeof(__node_base_ptr));
+      return __p;
+    }
+
+  template<typename _NodeAlloc>
+    void
+    _Hashtable_alloc<_NodeAlloc>::
+    _M_deallocate_buckets(__buckets_ptr __bkts,
+			  std::size_t __bkt_count)
+    {
+      typedef typename __buckets_alloc_traits::pointer _Ptr;
+      auto __ptr = std::pointer_traits<_Ptr>::pointer_to(*__bkts);
+      __buckets_alloc_type __alloc(_M_node_allocator());
+      __buckets_alloc_traits::deallocate(__alloc, __ptr, __bkt_count);
+    }
+
+ ///@} hashtable-detail
+} // namespace __detail
+/// @endcond
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif // _HASHTABLE_POLICY_H
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@indirect_array.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@indirect_array.h
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@indirect_array.h
@@ -0,0 +1,212 @@
+// The template and inlines for the -*- C++ -*- indirect_array class.
+
+// Copyright (C) 1997-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/indirect_array.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{valarray}
+ */
+
+// Written by Gabriel Dos Reis <Gabriel.Dos-Reis@DPTMaths.ENS-Cachan.Fr>
+
+#ifndef _INDIRECT_ARRAY_H
+#define _INDIRECT_ARRAY_H 1
+
+#pragma GCC system_header
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /**
+   * @addtogroup numeric_arrays
+   * @{
+   */
+
+  /**
+   *  @brief  Reference to arbitrary subset of an array.
+   *
+   *  An indirect_array is a reference to the actual elements of an array
+   *  specified by an ordered array of indices.  The way to get an
+   *  indirect_array is to call operator[](valarray<size_t>) on a valarray.
+   *  The returned indirect_array then permits carrying operations out on the
+   *  referenced subset of elements in the original valarray.
+   *
+   *  For example, if an indirect_array is obtained using the array (4,2,0) as
+   *  an argument, and then assigned to an array containing (1,2,3), then the
+   *  underlying array will have array[0]==3, array[2]==2, and array[4]==1.
+   *
+   *  @param  Tp  Element type.
+   */
+  template <class _Tp>
+    class indirect_array
+    {
+    public:
+      typedef _Tp value_type;
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 253. valarray helper functions are almost entirely useless
+
+      ///  Copy constructor.  Both slices refer to the same underlying array.
+      indirect_array(const indirect_array&);
+
+      ///  Assignment operator.  Assigns elements to corresponding elements
+      ///  of @a a.
+      indirect_array& operator=(const indirect_array&);
+
+      ///  Assign slice elements to corresponding elements of @a v.
+      void operator=(const valarray<_Tp>&) const;
+      ///  Multiply slice elements by corresponding elements of @a v.
+      void operator*=(const valarray<_Tp>&) const;
+      ///  Divide slice elements by corresponding elements of @a v.
+      void operator/=(const valarray<_Tp>&) const;
+      ///  Modulo slice elements by corresponding elements of @a v.
+      void operator%=(const valarray<_Tp>&) const;
+      ///  Add corresponding elements of @a v to slice elements.
+      void operator+=(const valarray<_Tp>&) const;
+      ///  Subtract corresponding elements of @a v from slice elements.
+      void operator-=(const valarray<_Tp>&) const;
+      ///  Logical xor slice elements with corresponding elements of @a v.
+      void operator^=(const valarray<_Tp>&) const;
+      ///  Logical and slice elements with corresponding elements of @a v.
+      void operator&=(const valarray<_Tp>&) const;
+      ///  Logical or slice elements with corresponding elements of @a v.
+      void operator|=(const valarray<_Tp>&) const;
+      ///  Left shift slice elements by corresponding elements of @a v.
+      void operator<<=(const valarray<_Tp>&) const;
+      ///  Right shift slice elements by corresponding elements of @a v.
+      void operator>>=(const valarray<_Tp>&) const;
+      ///  Assign all slice elements to @a t.
+      void operator= (const _Tp&) const;
+      //    ~indirect_array();
+
+      template<class _Dom>
+      void operator=(const _Expr<_Dom, _Tp>&) const;
+      template<class _Dom>
+      void operator*=(const _Expr<_Dom, _Tp>&) const;
+      template<class _Dom>
+      void operator/=(const _Expr<_Dom, _Tp>&) const;
+      template<class _Dom>
+      void operator%=(const _Expr<_Dom, _Tp>&) const;
+      template<class _Dom>
+      void operator+=(const _Expr<_Dom, _Tp>&) const;
+      template<class _Dom>
+      void operator-=(const _Expr<_Dom, _Tp>&) const;
+      template<class _Dom>
+      void operator^=(const _Expr<_Dom, _Tp>&) const;
+      template<class _Dom>
+      void operator&=(const _Expr<_Dom, _Tp>&) const;
+      template<class _Dom>
+      void operator|=(const _Expr<_Dom, _Tp>&) const;
+      template<class _Dom>
+      void operator<<=(const _Expr<_Dom, _Tp>&) const;
+      template<class _Dom>
+      void operator>>=(const _Expr<_Dom, _Tp>&) const;
+
+    private:
+      ///  Copy constructor.  Both slices refer to the same underlying array.
+      indirect_array(_Array<_Tp>, size_t, _Array<size_t>);
+
+      friend class valarray<_Tp>;
+      friend class gslice_array<_Tp>;
+
+      const size_t	 _M_sz;
+      const _Array<size_t> _M_index;
+      const _Array<_Tp>	 _M_array;
+
+      // not implemented
+      indirect_array();
+    };
+
+  template<typename _Tp>
+    inline
+    indirect_array<_Tp>::indirect_array(const indirect_array<_Tp>& __a)
+    : _M_sz(__a._M_sz), _M_index(__a._M_index), _M_array(__a._M_array) {}
+
+  template<typename _Tp>
+    inline
+    indirect_array<_Tp>::indirect_array(_Array<_Tp> __a, size_t __s,
+					_Array<size_t> __i)
+    : _M_sz(__s), _M_index(__i), _M_array(__a) {}
+
+  template<typename _Tp>
+    inline indirect_array<_Tp>&
+    indirect_array<_Tp>::operator=(const indirect_array<_Tp>& __a)
+    {
+      std::__valarray_copy(__a._M_array, _M_sz, __a._M_index, _M_array,
+			   _M_index);
+      return *this;
+    }
+
+  template<typename _Tp>
+    inline void
+    indirect_array<_Tp>::operator=(const _Tp& __t) const
+    { std::__valarray_fill(_M_array, _M_index, _M_sz, __t); }
+
+  template<typename _Tp>
+    inline void
+    indirect_array<_Tp>::operator=(const valarray<_Tp>& __v) const
+    { std::__valarray_copy(_Array<_Tp>(__v), _M_sz, _M_array, _M_index); }
+
+  template<typename _Tp>
+    template<class _Dom>
+      inline void
+      indirect_array<_Tp>::operator=(const _Expr<_Dom, _Tp>& __e) const
+      { std::__valarray_copy(__e, _M_sz, _M_array, _M_index); }
+
+#undef _DEFINE_VALARRAY_OPERATOR
+#define _DEFINE_VALARRAY_OPERATOR(_Op, _Name)				\
+  template<typename _Tp>						\
+    inline void								\
+    indirect_array<_Tp>::operator _Op##=(const valarray<_Tp>& __v) const\
+    {									\
+      _Array_augmented_##_Name(_M_array, _M_index, _Array<_Tp>(__v), _M_sz); \
+    }									\
+									\
+  template<typename _Tp>                                                \
+    template<class _Dom>				                \
+      inline void							\
+      indirect_array<_Tp>::operator _Op##=(const _Expr<_Dom,_Tp>& __e) const\
+      {									\
+	_Array_augmented_##_Name(_M_array, _M_index, __e, _M_sz);	\
+      }
+
+_DEFINE_VALARRAY_OPERATOR(*, __multiplies)
+_DEFINE_VALARRAY_OPERATOR(/, __divides)
+_DEFINE_VALARRAY_OPERATOR(%, __modulus)
+_DEFINE_VALARRAY_OPERATOR(+, __plus)
+_DEFINE_VALARRAY_OPERATOR(-, __minus)
+_DEFINE_VALARRAY_OPERATOR(^, __bitwise_xor)
+_DEFINE_VALARRAY_OPERATOR(&, __bitwise_and)
+_DEFINE_VALARRAY_OPERATOR(|, __bitwise_or)
+_DEFINE_VALARRAY_OPERATOR(<<, __shift_left)
+_DEFINE_VALARRAY_OPERATOR(>>, __shift_right)
+
+#undef _DEFINE_VALARRAY_OPERATOR
+
+  /// @} group numeric_arrays
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif /* _INDIRECT_ARRAY_H */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@indirect_array.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@indirect_array.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@invoke.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@invoke.h
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index 0000000000000000000000000000000000000000..cdecca0e2bfff219bef2d5d6f7325906d673a5be
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@invoke.h
@@ -0,0 +1,164 @@
+// Implementation of INVOKE -*- C++ -*-
+
+// Copyright (C) 2016-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file include/bits/invoke.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{functional}
+ */
+
+#ifndef _GLIBCXX_INVOKE_H
+#define _GLIBCXX_INVOKE_H 1
+
+#pragma GCC system_header
+
+#if __cplusplus < 201103L
+# include <bits/c++0x_warning.h>
+#else
+
+#include <type_traits>
+#include <bits/move.h> // forward
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /**
+   *  @addtogroup utilities
+   *  @{
+   */
+
+  // Used by __invoke_impl instead of std::forward<_Tp> so that a
+  // reference_wrapper is converted to an lvalue-reference.
+  template<typename _Tp, typename _Up = typename __inv_unwrap<_Tp>::type>
+    constexpr _Up&&
+    __invfwd(typename remove_reference<_Tp>::type& __t) noexcept
+    { return static_cast<_Up&&>(__t); }
+
+  template<typename _Res, typename _Fn, typename... _Args>
+    constexpr _Res
+    __invoke_impl(__invoke_other, _Fn&& __f, _Args&&... __args)
+    { return std::forward<_Fn>(__f)(std::forward<_Args>(__args)...); }
+
+  template<typename _Res, typename _MemFun, typename _Tp, typename... _Args>
+    constexpr _Res
+    __invoke_impl(__invoke_memfun_ref, _MemFun&& __f, _Tp&& __t,
+		  _Args&&... __args)
+    { return (__invfwd<_Tp>(__t).*__f)(std::forward<_Args>(__args)...); }
+
+  template<typename _Res, typename _MemFun, typename _Tp, typename... _Args>
+    constexpr _Res
+    __invoke_impl(__invoke_memfun_deref, _MemFun&& __f, _Tp&& __t,
+		  _Args&&... __args)
+    {
+      return ((*std::forward<_Tp>(__t)).*__f)(std::forward<_Args>(__args)...);
+    }
+
+  template<typename _Res, typename _MemPtr, typename _Tp>
+    constexpr _Res
+    __invoke_impl(__invoke_memobj_ref, _MemPtr&& __f, _Tp&& __t)
+    { return __invfwd<_Tp>(__t).*__f; }
+
+  template<typename _Res, typename _MemPtr, typename _Tp>
+    constexpr _Res
+    __invoke_impl(__invoke_memobj_deref, _MemPtr&& __f, _Tp&& __t)
+    { return (*std::forward<_Tp>(__t)).*__f; }
+
+  /// Invoke a callable object.
+  template<typename _Callable, typename... _Args>
+    constexpr typename __invoke_result<_Callable, _Args...>::type
+    __invoke(_Callable&& __fn, _Args&&... __args)
+    noexcept(__is_nothrow_invocable<_Callable, _Args...>::value)
+    {
+      using __result = __invoke_result<_Callable, _Args...>;
+      using __type = typename __result::type;
+      using __tag = typename __result::__invoke_type;
+      return std::__invoke_impl<__type>(__tag{}, std::forward<_Callable>(__fn),
+					std::forward<_Args>(__args)...);
+    }
+
+#if __cplusplus >= 201703L
+  // INVOKE<R>: Invoke a callable object and convert the result to R.
+  template<typename _Res, typename _Callable, typename... _Args>
+    constexpr enable_if_t<is_invocable_r_v<_Res, _Callable, _Args...>, _Res>
+    __invoke_r(_Callable&& __fn, _Args&&... __args)
+    noexcept(is_nothrow_invocable_r_v<_Res, _Callable, _Args...>)
+    {
+      using __result = __invoke_result<_Callable, _Args...>;
+      using __type = typename __result::type;
+      using __tag = typename __result::__invoke_type;
+      if constexpr (is_void_v<_Res>)
+	std::__invoke_impl<__type>(__tag{}, std::forward<_Callable>(__fn),
+					std::forward<_Args>(__args)...);
+      else
+	return std::__invoke_impl<__type>(__tag{},
+					  std::forward<_Callable>(__fn),
+					  std::forward<_Args>(__args)...);
+    }
+#else // C++11
+  template<typename _Res, typename _Callable, typename... _Args>
+    using __can_invoke_as_void = __enable_if_t<
+      __and_<is_void<_Res>, __is_invocable<_Callable, _Args...>>::value,
+      _Res
+    >;
+
+  template<typename _Res, typename _Callable, typename... _Args>
+    using __can_invoke_as_nonvoid = __enable_if_t<
+      __and_<__not_<is_void<_Res>>,
+	     is_convertible<typename __invoke_result<_Callable, _Args...>::type,
+			    _Res>
+      >::value,
+      _Res
+    >;
+
+  // INVOKE<R>: Invoke a callable object and convert the result to R.
+  template<typename _Res, typename _Callable, typename... _Args>
+    constexpr __can_invoke_as_nonvoid<_Res, _Callable, _Args...>
+    __invoke_r(_Callable&& __fn, _Args&&... __args)
+    {
+      using __result = __invoke_result<_Callable, _Args...>;
+      using __type = typename __result::type;
+      using __tag = typename __result::__invoke_type;
+      return std::__invoke_impl<__type>(__tag{}, std::forward<_Callable>(__fn),
+					std::forward<_Args>(__args)...);
+    }
+
+  // INVOKE<R> when R is cv void
+  template<typename _Res, typename _Callable, typename... _Args>
+    _GLIBCXX14_CONSTEXPR __can_invoke_as_void<_Res, _Callable, _Args...>
+    __invoke_r(_Callable&& __fn, _Args&&... __args)
+    {
+      using __result = __invoke_result<_Callable, _Args...>;
+      using __type = typename __result::type;
+      using __tag = typename __result::__invoke_type;
+      std::__invoke_impl<__type>(__tag{}, std::forward<_Callable>(__fn),
+				 std::forward<_Args>(__args)...);
+    }
+#endif // C++11
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif // C++11
+
+#endif // _GLIBCXX_INVOKE_H
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@@ -0,0 +1,1118 @@
+// Iostreams base classes -*- C++ -*-
+
+// Copyright (C) 1997-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/ios_base.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{ios}
+ */
+
+//
+// ISO C++ 14882: 27.4  Iostreams base classes
+//
+
+#ifndef _IOS_BASE_H
+#define _IOS_BASE_H 1
+
+#pragma GCC system_header
+
+#include <ext/atomicity.h>
+#include <bits/localefwd.h>
+#include <bits/locale_classes.h>
+
+#if __cplusplus < 201103L
+# include <stdexcept>
+#else
+# include <system_error>
+#endif
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  // The following definitions of bitmask types are enums, not ints,
+  // as permitted (but not required) in the standard, in order to provide
+  // better type safety in iostream calls.  A side effect is that in C++98
+  // expressions involving them are not compile-time constants.
+  enum _Ios_Fmtflags 
+    { 
+      _S_boolalpha 	= 1L << 0,
+      _S_dec 		= 1L << 1,
+      _S_fixed 		= 1L << 2,
+      _S_hex 		= 1L << 3,
+      _S_internal 	= 1L << 4,
+      _S_left 		= 1L << 5,
+      _S_oct 		= 1L << 6,
+      _S_right 		= 1L << 7,
+      _S_scientific 	= 1L << 8,
+      _S_showbase 	= 1L << 9,
+      _S_showpoint 	= 1L << 10,
+      _S_showpos 	= 1L << 11,
+      _S_skipws 	= 1L << 12,
+      _S_unitbuf 	= 1L << 13,
+      _S_uppercase 	= 1L << 14,
+      _S_adjustfield 	= _S_left | _S_right | _S_internal,
+      _S_basefield 	= _S_dec | _S_oct | _S_hex,
+      _S_floatfield 	= _S_scientific | _S_fixed,
+      _S_ios_fmtflags_end = 1L << 16,
+      _S_ios_fmtflags_max = __INT_MAX__,
+      _S_ios_fmtflags_min = ~__INT_MAX__
+    };
+
+  inline _GLIBCXX_CONSTEXPR _Ios_Fmtflags
+  operator&(_Ios_Fmtflags __a, _Ios_Fmtflags __b)
+  { return _Ios_Fmtflags(static_cast<int>(__a) & static_cast<int>(__b)); }
+
+  inline _GLIBCXX_CONSTEXPR _Ios_Fmtflags
+  operator|(_Ios_Fmtflags __a, _Ios_Fmtflags __b)
+  { return _Ios_Fmtflags(static_cast<int>(__a) | static_cast<int>(__b)); }
+
+  inline _GLIBCXX_CONSTEXPR _Ios_Fmtflags
+  operator^(_Ios_Fmtflags __a, _Ios_Fmtflags __b)
+  { return _Ios_Fmtflags(static_cast<int>(__a) ^ static_cast<int>(__b)); }
+
+  inline _GLIBCXX_CONSTEXPR _Ios_Fmtflags
+  operator~(_Ios_Fmtflags __a)
+  { return _Ios_Fmtflags(~static_cast<int>(__a)); }
+
+  inline const _Ios_Fmtflags&
+  operator|=(_Ios_Fmtflags& __a, _Ios_Fmtflags __b)
+  { return __a = __a | __b; }
+
+  inline const _Ios_Fmtflags&
+  operator&=(_Ios_Fmtflags& __a, _Ios_Fmtflags __b)
+  { return __a = __a & __b; }
+
+  inline const _Ios_Fmtflags&
+  operator^=(_Ios_Fmtflags& __a, _Ios_Fmtflags __b)
+  { return __a = __a ^ __b; }
+
+
+  enum _Ios_Openmode 
+    { 
+      _S_app 		= 1L << 0,
+      _S_ate 		= 1L << 1,
+      _S_bin 		= 1L << 2,
+      _S_in 		= 1L << 3,
+      _S_out 		= 1L << 4,
+      _S_trunc 		= 1L << 5,
+      _S_noreplace 	= 1L << 6,
+      _S_ios_openmode_end = 1L << 16,
+      _S_ios_openmode_max = __INT_MAX__,
+      _S_ios_openmode_min = ~__INT_MAX__
+    };
+
+  inline _GLIBCXX_CONSTEXPR _Ios_Openmode
+  operator&(_Ios_Openmode __a, _Ios_Openmode __b)
+  { return _Ios_Openmode(static_cast<int>(__a) & static_cast<int>(__b)); }
+
+  inline _GLIBCXX_CONSTEXPR _Ios_Openmode
+  operator|(_Ios_Openmode __a, _Ios_Openmode __b)
+  { return _Ios_Openmode(static_cast<int>(__a) | static_cast<int>(__b)); }
+
+  inline _GLIBCXX_CONSTEXPR _Ios_Openmode
+  operator^(_Ios_Openmode __a, _Ios_Openmode __b)
+  { return _Ios_Openmode(static_cast<int>(__a) ^ static_cast<int>(__b)); }
+
+  inline _GLIBCXX_CONSTEXPR _Ios_Openmode
+  operator~(_Ios_Openmode __a)
+  { return _Ios_Openmode(~static_cast<int>(__a)); }
+
+  inline const _Ios_Openmode&
+  operator|=(_Ios_Openmode& __a, _Ios_Openmode __b)
+  { return __a = __a | __b; }
+
+  inline const _Ios_Openmode&
+  operator&=(_Ios_Openmode& __a, _Ios_Openmode __b)
+  { return __a = __a & __b; }
+
+  inline const _Ios_Openmode&
+  operator^=(_Ios_Openmode& __a, _Ios_Openmode __b)
+  { return __a = __a ^ __b; }
+
+
+  enum _Ios_Iostate
+    { 
+      _S_goodbit 		= 0,
+      _S_badbit 		= 1L << 0,
+      _S_eofbit 		= 1L << 1,
+      _S_failbit		= 1L << 2,
+      _S_ios_iostate_end = 1L << 16,
+      _S_ios_iostate_max = __INT_MAX__,
+      _S_ios_iostate_min = ~__INT_MAX__
+    };
+
+  inline _GLIBCXX_CONSTEXPR _Ios_Iostate
+  operator&(_Ios_Iostate __a, _Ios_Iostate __b)
+  { return _Ios_Iostate(static_cast<int>(__a) & static_cast<int>(__b)); }
+
+  inline _GLIBCXX_CONSTEXPR _Ios_Iostate
+  operator|(_Ios_Iostate __a, _Ios_Iostate __b)
+  { return _Ios_Iostate(static_cast<int>(__a) | static_cast<int>(__b)); }
+
+  inline _GLIBCXX_CONSTEXPR _Ios_Iostate
+  operator^(_Ios_Iostate __a, _Ios_Iostate __b)
+  { return _Ios_Iostate(static_cast<int>(__a) ^ static_cast<int>(__b)); }
+
+  inline _GLIBCXX_CONSTEXPR _Ios_Iostate
+  operator~(_Ios_Iostate __a)
+  { return _Ios_Iostate(~static_cast<int>(__a)); }
+
+  inline const _Ios_Iostate&
+  operator|=(_Ios_Iostate& __a, _Ios_Iostate __b)
+  { return __a = __a | __b; }
+
+  inline const _Ios_Iostate&
+  operator&=(_Ios_Iostate& __a, _Ios_Iostate __b)
+  { return __a = __a & __b; }
+
+  inline const  _Ios_Iostate&
+  operator^=(_Ios_Iostate& __a, _Ios_Iostate __b)
+  { return __a = __a ^ __b; }
+
+
+  enum _Ios_Seekdir 
+    { 
+      _S_beg = 0,
+      _S_cur = _GLIBCXX_STDIO_SEEK_CUR,
+      _S_end = _GLIBCXX_STDIO_SEEK_END,
+      _S_ios_seekdir_end = 1L << 16 
+    };
+
+#if __cplusplus >= 201103L
+  /// I/O error code
+  enum class io_errc { stream = 1 };
+
+  template <> struct is_error_code_enum<io_errc> : public true_type { };
+
+  const error_category& iostream_category() noexcept;
+
+  inline error_code
+  make_error_code(io_errc __e) noexcept
+  { return error_code(static_cast<int>(__e), iostream_category()); }
+
+  inline error_condition
+  make_error_condition(io_errc __e) noexcept
+  { return error_condition(static_cast<int>(__e), iostream_category()); }
+#endif
+
+  // 27.4.2  Class ios_base
+  /**
+   *  @brief  The base of the I/O class hierarchy.
+   *  @ingroup io
+   *
+   *  This class defines everything that can be defined about I/O that does
+   *  not depend on the type of characters being input or output.  Most
+   *  people will only see @c ios_base when they need to specify the full
+   *  name of the various I/O flags (e.g., the openmodes).
+  */
+  class ios_base
+  {
+#if _GLIBCXX_USE_CXX11_ABI
+#if __cplusplus < 201103L
+    // Type that is layout-compatible with std::system_error
+    struct system_error : std::runtime_error
+    {
+      // Type that is layout-compatible with std::error_code
+      struct error_code
+      {
+	error_code() { }
+      private:
+	int		_M_value;
+	const void*	_M_cat;
+      } _M_code;
+    };
+#endif
+#endif
+  public:
+
+    /** 
+     *  @brief These are thrown to indicate problems with io.
+     *  @ingroup exceptions
+     *
+     *  27.4.2.1.1  Class ios_base::failure
+     */
+#if _GLIBCXX_USE_CXX11_ABI
+    class _GLIBCXX_ABI_TAG_CXX11 failure : public system_error
+    {
+    public:
+      explicit
+      failure(const string& __str);
+
+#if __cplusplus >= 201103L
+      explicit
+      failure(const string&, const error_code&);
+
+      explicit
+      failure(const char*, const error_code& = io_errc::stream);
+#endif
+
+      virtual
+      ~failure() throw();
+
+      virtual const char*
+      what() const throw();
+    };
+#else
+    class failure : public exception
+    {
+    public:
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 48.  Use of non-existent exception constructor
+      explicit
+      failure(const string& __str) throw();
+
+      // This declaration is not useless:
+      // http://gcc.gnu.org/onlinedocs/gcc-4.3.2/gcc/Vague-Linkage.html
+      virtual
+      ~failure() throw();
+
+      virtual const char*
+      what() const throw();
+
+#if __cplusplus >= 201103L
+      // Define the new members required by C++11,
+      // even though the error_code cannot be stored.
+
+      explicit
+      failure(const string& __s, const error_code&) noexcept
+      : failure(__s)
+      { }
+
+      explicit
+      failure(const char* __s, const error_code& = error_code{})
+      : failure(string(__s))
+      { }
+
+      // Stand-in for system_error::code() but returning by value.
+      error_code code() const noexcept { return error_code{}; }
+#endif
+
+    private:
+      string _M_msg;
+    };
+#endif
+
+    // 27.4.2.1.2  Type ios_base::fmtflags
+    /**
+     *  @brief This is a bitmask type.
+     *
+     *  @c @a _Ios_Fmtflags is implementation-defined, but it is valid to
+     *  perform bitwise operations on these values and expect the Right
+     *  Thing to happen.  Defined objects of type fmtflags are:
+     *  - boolalpha
+     *  - dec
+     *  - fixed
+     *  - hex
+     *  - internal
+     *  - left
+     *  - oct
+     *  - right
+     *  - scientific
+     *  - showbase
+     *  - showpoint
+     *  - showpos
+     *  - skipws
+     *  - unitbuf
+     *  - uppercase
+     *  - adjustfield
+     *  - basefield
+     *  - floatfield
+    */
+    typedef _Ios_Fmtflags fmtflags;
+
+    /// Insert/extract @c bool in alphabetic rather than numeric format.
+    static const fmtflags boolalpha =   _S_boolalpha;
+
+    /// Converts integer input or generates integer output in decimal base.
+    static const fmtflags dec =         _S_dec;
+
+    /// Generate floating-point output in fixed-point notation.
+    static const fmtflags fixed =       _S_fixed;
+
+    /// Converts integer input or generates integer output in hexadecimal base.
+    static const fmtflags hex =         _S_hex;
+
+    /// Adds fill characters at a designated internal point in certain
+    /// generated output, or identical to @c right if no such point is
+    /// designated.
+    static const fmtflags internal =    _S_internal;
+
+    /// Adds fill characters on the right (final positions) of certain
+    /// generated output.  (I.e., the thing you print is flush left.)
+    static const fmtflags left =        _S_left;
+
+    /// Converts integer input or generates integer output in octal base.
+    static const fmtflags oct =         _S_oct;
+
+    /// Adds fill characters on the left (initial positions) of certain
+    /// generated output.  (I.e., the thing you print is flush right.)
+    static const fmtflags right =       _S_right;
+
+    /// Generates floating-point output in scientific notation.
+    static const fmtflags scientific =  _S_scientific;
+
+    /// Generates a prefix indicating the numeric base of generated integer
+    /// output.
+    static const fmtflags showbase =    _S_showbase;
+
+    /// Generates a decimal-point character unconditionally in generated
+    /// floating-point output.
+    static const fmtflags showpoint =   _S_showpoint;
+
+    /// Generates a + sign in non-negative generated numeric output.
+    static const fmtflags showpos =     _S_showpos;
+
+    /// Skips leading white space before certain input operations.
+    static const fmtflags skipws =      _S_skipws;
+
+    /// Flushes output after each output operation.
+    static const fmtflags unitbuf =     _S_unitbuf;
+
+    /// Replaces certain lowercase letters with their uppercase equivalents
+    /// in generated output.
+    static const fmtflags uppercase =   _S_uppercase;
+
+    /// A mask of left|right|internal.  Useful for the 2-arg form of @c setf.
+    static const fmtflags adjustfield = _S_adjustfield;
+
+    /// A mask of dec|oct|hex.  Useful for the 2-arg form of @c setf.
+    static const fmtflags basefield =   _S_basefield;
+
+    /// A mask of scientific|fixed.  Useful for the 2-arg form of @c setf.
+    static const fmtflags floatfield =  _S_floatfield;
+
+    // 27.4.2.1.3  Type ios_base::iostate
+    /**
+     *  @brief This is a bitmask type.
+     *
+     *  @c @a _Ios_Iostate is implementation-defined, but it is valid to
+     *  perform bitwise operations on these values and expect the Right
+     *  Thing to happen.  Defined objects of type iostate are:
+     *  - badbit
+     *  - eofbit
+     *  - failbit
+     *  - goodbit
+    */
+    typedef _Ios_Iostate iostate;
+
+    /// Indicates a loss of integrity in an input or output sequence (such
+    /// as an irrecoverable read error from a file).
+    static const iostate badbit =	_S_badbit;
+
+    /// Indicates that an input operation reached the end of an input sequence.
+    static const iostate eofbit =	_S_eofbit;
+
+    /// Indicates that an input operation failed to read the expected
+    /// characters, or that an output operation failed to generate the
+    /// desired characters.
+    static const iostate failbit =	_S_failbit;
+
+    /// Indicates all is well.
+    static const iostate goodbit =	_S_goodbit;
+
+    // 27.4.2.1.4  Type ios_base::openmode
+    /**
+     *  @brief This is a bitmask type.
+     *
+     *  @c @a _Ios_Openmode is implementation-defined, but it is valid to
+     *  perform bitwise operations on these values and expect the Right
+     *  Thing to happen.  Defined objects of type openmode are:
+     *  - app
+     *  - ate
+     *  - binary
+     *  - in
+     *  - out
+     *  - trunc
+    */
+    typedef _Ios_Openmode openmode;
+
+    /// Seek to end before each write.
+    static const openmode app =		_S_app;
+
+    /// Open and seek to end immediately after opening.
+    static const openmode ate =		_S_ate;
+
+    /// Perform input and output in binary mode (as opposed to text mode).
+    /// This is probably not what you think it is; see
+    /// https://gcc.gnu.org/onlinedocs/libstdc++/manual/fstreams.html#std.io.filestreams.binary
+    static const openmode binary =	_S_bin;
+
+    /// Open for input.  Default for @c ifstream and fstream.
+    static const openmode in =		_S_in;
+
+    /// Open for output.  Default for @c ofstream and fstream.
+    static const openmode out =		_S_out;
+
+    /// Truncate an existing stream when opening.  Default for @c ofstream.
+    static const openmode trunc =	_S_trunc;
+
+    static const openmode __noreplace =	_S_noreplace;
+
+#if __cplusplus >= 202100L
+#define __cpp_lib_ios_noreplace 202207L
+    /// Open a file in exclusive mode.
+    static const openmode noreplace =	_S_noreplace;
+#endif
+
+    // 27.4.2.1.5  Type ios_base::seekdir
+    /**
+     *  @brief This is an enumerated type.
+     *
+     *  @c @a _Ios_Seekdir is implementation-defined.  Defined values
+     *  of type seekdir are:
+     *  - beg
+     *  - cur, equivalent to @c SEEK_CUR in the C standard library.
+     *  - end, equivalent to @c SEEK_END in the C standard library.
+    */
+    typedef _Ios_Seekdir seekdir;
+
+    /// Request a seek relative to the beginning of the stream.
+    static const seekdir beg =		_S_beg;
+
+    /// Request a seek relative to the current position within the sequence.
+    static const seekdir cur =		_S_cur;
+
+    /// Request a seek relative to the current end of the sequence.
+    static const seekdir end =		_S_end;
+
+#if __cplusplus <= 201402L
+    // Annex D.6 (removed in C++17)
+    typedef int io_state
+      _GLIBCXX_DEPRECATED_SUGGEST("std::iostate");
+    typedef int open_mode
+      _GLIBCXX_DEPRECATED_SUGGEST("std::openmode");
+    typedef int seek_dir
+      _GLIBCXX_DEPRECATED_SUGGEST("std::seekdir");
+
+    typedef std::streampos streampos
+      _GLIBCXX_DEPRECATED_SUGGEST("std::streampos");
+    typedef std::streamoff streamoff
+      _GLIBCXX_DEPRECATED_SUGGEST("std::streamoff");
+#endif
+
+    // Callbacks;
+    /**
+     *  @brief  The set of events that may be passed to an event callback.
+     *
+     *  erase_event is used during ~ios() and copyfmt().  imbue_event is used
+     *  during imbue().  copyfmt_event is used during copyfmt().
+    */
+    enum event
+    {
+      erase_event,
+      imbue_event,
+      copyfmt_event
+    };
+
+    /**
+     *  @brief  The type of an event callback function.
+     *  @param  __e  One of the members of the event enum.
+     *  @param  __b  Reference to the ios_base object.
+     *  @param  __i  The integer provided when the callback was registered.
+     *
+     *  Event callbacks are user defined functions that get called during
+     *  several ios_base and basic_ios functions, specifically imbue(),
+     *  copyfmt(), and ~ios().
+    */
+    typedef void (*event_callback) (event __e, ios_base& __b, int __i);
+
+    /**
+     *  @brief  Add the callback __fn with parameter __index.
+     *  @param  __fn  The function to add.
+     *  @param  __index  The integer to pass to the function when invoked.
+     *
+     *  Registers a function as an event callback with an integer parameter to
+     *  be passed to the function when invoked.  Multiple copies of the
+     *  function are allowed.  If there are multiple callbacks, they are
+     *  invoked in the order they were registered.
+    */
+    void
+    register_callback(event_callback __fn, int __index);
+
+  protected:
+    streamsize		_M_precision;
+    streamsize		_M_width;
+    fmtflags		_M_flags;
+    iostate		_M_exception;
+    iostate		_M_streambuf_state;
+
+    // 27.4.2.6  Members for callbacks
+    // 27.4.2.6  ios_base callbacks
+    struct _Callback_list
+    {
+      // Data Members
+      _Callback_list*		_M_next;
+      ios_base::event_callback	_M_fn;
+      int			_M_index;
+      _Atomic_word		_M_refcount;  // 0 means one reference.
+
+      _Callback_list(ios_base::event_callback __fn, int __index,
+		     _Callback_list* __cb)
+      : _M_next(__cb), _M_fn(__fn), _M_index(__index), _M_refcount(0) { }
+
+      void
+      _M_add_reference() { __gnu_cxx::__atomic_add_dispatch(&_M_refcount, 1); }
+
+      // 0 => OK to delete.
+      int
+      _M_remove_reference() 
+      {
+        // Be race-detector-friendly.  For more info see bits/c++config.
+        _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&_M_refcount);
+        int __res = __gnu_cxx::__exchange_and_add_dispatch(&_M_refcount, -1);
+        if (__res == 0)
+          {
+            _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&_M_refcount);
+          }
+        return __res;
+      }
+    };
+
+     _Callback_list*	_M_callbacks;
+
+    void
+    _M_call_callbacks(event __ev) throw();
+
+    void
+    _M_dispose_callbacks(void) throw();
+
+    // 27.4.2.5  Members for iword/pword storage
+    struct _Words
+    {
+      void*	_M_pword;
+      long	_M_iword;
+      _Words() : _M_pword(0), _M_iword(0) { }
+    };
+
+    // Only for failed iword/pword calls.
+    _Words		_M_word_zero;
+
+    // Guaranteed storage.
+    // The first 5 iword and pword slots are reserved for internal use.
+    enum { _S_local_word_size = 8 };
+    _Words		_M_local_word[_S_local_word_size];
+
+    // Allocated storage.
+    int			_M_word_size;
+    _Words*		_M_word;
+
+    _Words&
+    _M_grow_words(int __index, bool __iword);
+
+    // Members for locale and locale caching.
+    locale		_M_ios_locale;
+
+    void
+    _M_init() throw();
+
+  public:
+
+    // 27.4.2.1.6  Class ios_base::Init
+    // Used to initialize standard streams. In theory, g++ could use
+    // -finit-priority to order this stuff correctly without going
+    // through these machinations.
+    class Init
+    {
+      friend class ios_base;
+    public:
+      Init();
+      ~Init();
+
+#if __cplusplus >= 201103L
+      Init(const Init&) = default;
+      Init& operator=(const Init&) = default;
+#endif
+
+    private:
+      static _Atomic_word	_S_refcount;
+      static bool		_S_synced_with_stdio;
+    };
+
+    // [27.4.2.2] fmtflags state functions
+    /**
+     *  @brief  Access to format flags.
+     *  @return  The format control flags for both input and output.
+    */
+    fmtflags
+    flags() const
+    { return _M_flags; }
+
+    /**
+     *  @brief  Setting new format flags all at once.
+     *  @param  __fmtfl  The new flags to set.
+     *  @return  The previous format control flags.
+     *
+     *  This function overwrites all the format flags with @a __fmtfl.
+    */
+    fmtflags
+    flags(fmtflags __fmtfl)
+    {
+      fmtflags __old = _M_flags;
+      _M_flags = __fmtfl;
+      return __old;
+    }
+
+    /**
+     *  @brief  Setting new format flags.
+     *  @param  __fmtfl  Additional flags to set.
+     *  @return  The previous format control flags.
+     *
+     *  This function sets additional flags in format control.  Flags that
+     *  were previously set remain set.
+    */
+    fmtflags
+    setf(fmtflags __fmtfl)
+    {
+      fmtflags __old = _M_flags;
+      _M_flags |= __fmtfl;
+      return __old;
+    }
+
+    /**
+     *  @brief  Setting new format flags.
+     *  @param  __fmtfl  Additional flags to set.
+     *  @param  __mask  The flags mask for @a fmtfl.
+     *  @return  The previous format control flags.
+     *
+     *  This function clears @a mask in the format flags, then sets
+     *  @a fmtfl @c & @a mask.  An example mask is @c ios_base::adjustfield.
+    */
+    fmtflags
+    setf(fmtflags __fmtfl, fmtflags __mask)
+    {
+      fmtflags __old = _M_flags;
+      _M_flags &= ~__mask;
+      _M_flags |= (__fmtfl & __mask);
+      return __old;
+    }
+
+    /**
+     *  @brief  Clearing format flags.
+     *  @param  __mask  The flags to unset.
+     *
+     *  This function clears @a __mask in the format flags.
+    */
+    void
+    unsetf(fmtflags __mask)
+    { _M_flags &= ~__mask; }
+
+    /**
+     *  @brief  Flags access.
+     *  @return  The precision to generate on certain output operations.
+     *
+     *  Be careful if you try to give a definition of @a precision here; see
+     *  DR 189.
+    */
+    streamsize
+    precision() const
+    { return _M_precision; }
+
+    /**
+     *  @brief  Changing flags.
+     *  @param  __prec  The new precision value.
+     *  @return  The previous value of precision().
+    */
+    streamsize
+    precision(streamsize __prec)
+    {
+      streamsize __old = _M_precision;
+      _M_precision = __prec;
+      return __old;
+    }
+
+    /**
+     *  @brief  Flags access.
+     *  @return  The minimum field width to generate on output operations.
+     *
+     *  <em>Minimum field width</em> refers to the number of characters.
+    */
+    streamsize
+    width() const
+    { return _M_width; }
+
+    /**
+     *  @brief  Changing flags.
+     *  @param  __wide  The new width value.
+     *  @return  The previous value of width().
+    */
+    streamsize
+    width(streamsize __wide)
+    {
+      streamsize __old = _M_width;
+      _M_width = __wide;
+      return __old;
+    }
+
+    // [27.4.2.4] ios_base static members
+    /**
+     *  @brief  Interaction with the standard C I/O objects.
+     *  @param  __sync  Whether to synchronize or not.
+     *  @return  True if the standard streams were previously synchronized.
+     *
+     *  The synchronization referred to is @e only that between the standard
+     *  C facilities (e.g., stdout) and the standard C++ objects (e.g.,
+     *  cout).  User-declared streams are unaffected.  See
+     *  https://gcc.gnu.org/onlinedocs/libstdc++/manual/fstreams.html#std.io.filestreams.binary
+    */
+    static bool
+    sync_with_stdio(bool __sync = true);
+
+    // [27.4.2.3] ios_base locale functions
+    /**
+     *  @brief  Setting a new locale.
+     *  @param  __loc  The new locale.
+     *  @return  The previous locale.
+     *
+     *  Sets the new locale for this stream, and then invokes each callback
+     *  with imbue_event.
+    */
+    locale
+    imbue(const locale& __loc) throw();
+
+    /**
+     *  @brief  Locale access
+     *  @return  A copy of the current locale.
+     *
+     *  If @c imbue(loc) has previously been called, then this function
+     *  returns @c loc.  Otherwise, it returns a copy of @c std::locale(),
+     *  the global C++ locale.
+    */
+    locale
+    getloc() const
+    { return _M_ios_locale; }
+
+    /**
+     *  @brief  Locale access
+     *  @return  A reference to the current locale.
+     *
+     *  Like getloc above, but returns a reference instead of
+     *  generating a copy.
+    */
+    const locale&
+    _M_getloc() const
+    { return _M_ios_locale; }
+
+    // [27.4.2.5] ios_base storage functions
+    /**
+     *  @brief  Access to unique indices.
+     *  @return  An integer different from all previous calls.
+     *
+     *  This function returns a unique integer every time it is called.  It
+     *  can be used for any purpose, but is primarily intended to be a unique
+     *  index for the iword and pword functions.  The expectation is that an
+     *  application calls xalloc in order to obtain an index in the iword and
+     *  pword arrays that can be used without fear of conflict.
+     *
+     *  The implementation maintains a static variable that is incremented and
+     *  returned on each invocation.  xalloc is guaranteed to return an index
+     *  that is safe to use in the iword and pword arrays.
+    */
+    static int
+    xalloc() throw();
+
+    /**
+     *  @brief  Access to integer array.
+     *  @param  __ix  Index into the array.
+     *  @return  A reference to an integer associated with the index.
+     *
+     *  The iword function provides access to an array of integers that can be
+     *  used for any purpose.  The array grows as required to hold the
+     *  supplied index.  All integers in the array are initialized to 0.
+     *
+     *  The implementation reserves several indices.  You should use xalloc to
+     *  obtain an index that is safe to use.  Also note that since the array
+     *  can grow dynamically, it is not safe to hold onto the reference.
+    */
+    long&
+    iword(int __ix)
+    {
+      _Words& __word = ((unsigned)__ix < (unsigned)_M_word_size)
+			? _M_word[__ix] : _M_grow_words(__ix, true);
+      return __word._M_iword;
+    }
+
+    /**
+     *  @brief  Access to void pointer array.
+     *  @param  __ix  Index into the array.
+     *  @return  A reference to a void* associated with the index.
+     *
+     *  The pword function provides access to an array of pointers that can be
+     *  used for any purpose.  The array grows as required to hold the
+     *  supplied index.  All pointers in the array are initialized to 0.
+     *
+     *  The implementation reserves several indices.  You should use xalloc to
+     *  obtain an index that is safe to use.  Also note that since the array
+     *  can grow dynamically, it is not safe to hold onto the reference.
+    */
+    void*&
+    pword(int __ix)
+    {
+      _Words& __word = ((unsigned)__ix < (unsigned)_M_word_size)
+			? _M_word[__ix] : _M_grow_words(__ix, false);
+      return __word._M_pword;
+    }
+
+    // Destructor
+    /**
+     *  Invokes each callback with erase_event.  Destroys local storage.
+     *
+     *  Note that the ios_base object for the standard streams never gets
+     *  destroyed.  As a result, any callbacks registered with the standard
+     *  streams will not get invoked with erase_event (unless copyfmt is
+     *  used).
+    */
+    virtual ~ios_base();
+
+  protected:
+    ios_base() throw ();
+
+#if __cplusplus < 201103L
+  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+  // 50.  Copy constructor and assignment operator of ios_base
+  private:
+    ios_base(const ios_base&);
+
+    ios_base&
+    operator=(const ios_base&);
+#else
+  public:
+    ios_base(const ios_base&) = delete;
+
+    ios_base&
+    operator=(const ios_base&) = delete;
+
+  protected:
+    void
+    _M_move(ios_base&) noexcept;
+
+    void
+    _M_swap(ios_base& __rhs) noexcept;
+#endif
+  };
+
+  // [27.4.5.1] fmtflags manipulators
+  /// Calls base.setf(ios_base::boolalpha).
+  inline ios_base&
+  boolalpha(ios_base& __base)
+  {
+    __base.setf(ios_base::boolalpha);
+    return __base;
+  }
+
+  /// Calls base.unsetf(ios_base::boolalpha).
+  inline ios_base&
+  noboolalpha(ios_base& __base)
+  {
+    __base.unsetf(ios_base::boolalpha);
+    return __base;
+  }
+
+  /// Calls base.setf(ios_base::showbase).
+  inline ios_base&
+  showbase(ios_base& __base)
+  {
+    __base.setf(ios_base::showbase);
+    return __base;
+  }
+
+  /// Calls base.unsetf(ios_base::showbase).
+  inline ios_base&
+  noshowbase(ios_base& __base)
+  {
+    __base.unsetf(ios_base::showbase);
+    return __base;
+  }
+
+  /// Calls base.setf(ios_base::showpoint).
+  inline ios_base&
+  showpoint(ios_base& __base)
+  {
+    __base.setf(ios_base::showpoint);
+    return __base;
+  }
+
+  /// Calls base.unsetf(ios_base::showpoint).
+  inline ios_base&
+  noshowpoint(ios_base& __base)
+  {
+    __base.unsetf(ios_base::showpoint);
+    return __base;
+  }
+
+  /// Calls base.setf(ios_base::showpos).
+  inline ios_base&
+  showpos(ios_base& __base)
+  {
+    __base.setf(ios_base::showpos);
+    return __base;
+  }
+
+  /// Calls base.unsetf(ios_base::showpos).
+  inline ios_base&
+  noshowpos(ios_base& __base)
+  {
+    __base.unsetf(ios_base::showpos);
+    return __base;
+  }
+
+  /// Calls base.setf(ios_base::skipws).
+  inline ios_base&
+  skipws(ios_base& __base)
+  {
+    __base.setf(ios_base::skipws);
+    return __base;
+  }
+
+  /// Calls base.unsetf(ios_base::skipws).
+  inline ios_base&
+  noskipws(ios_base& __base)
+  {
+    __base.unsetf(ios_base::skipws);
+    return __base;
+  }
+
+  /// Calls base.setf(ios_base::uppercase).
+  inline ios_base&
+  uppercase(ios_base& __base)
+  {
+    __base.setf(ios_base::uppercase);
+    return __base;
+  }
+
+  /// Calls base.unsetf(ios_base::uppercase).
+  inline ios_base&
+  nouppercase(ios_base& __base)
+  {
+    __base.unsetf(ios_base::uppercase);
+    return __base;
+  }
+
+  /// Calls base.setf(ios_base::unitbuf).
+  inline ios_base&
+  unitbuf(ios_base& __base)
+  {
+     __base.setf(ios_base::unitbuf);
+     return __base;
+  }
+
+  /// Calls base.unsetf(ios_base::unitbuf).
+  inline ios_base&
+  nounitbuf(ios_base& __base)
+  {
+     __base.unsetf(ios_base::unitbuf);
+     return __base;
+  }
+
+  // [27.4.5.2] adjustfield manipulators
+  /// Calls base.setf(ios_base::internal, ios_base::adjustfield).
+  inline ios_base&
+  internal(ios_base& __base)
+  {
+     __base.setf(ios_base::internal, ios_base::adjustfield);
+     return __base;
+  }
+
+  /// Calls base.setf(ios_base::left, ios_base::adjustfield).
+  inline ios_base&
+  left(ios_base& __base)
+  {
+    __base.setf(ios_base::left, ios_base::adjustfield);
+    return __base;
+  }
+
+  /// Calls base.setf(ios_base::right, ios_base::adjustfield).
+  inline ios_base&
+  right(ios_base& __base)
+  {
+    __base.setf(ios_base::right, ios_base::adjustfield);
+    return __base;
+  }
+
+  // [27.4.5.3] basefield manipulators
+  /// Calls base.setf(ios_base::dec, ios_base::basefield).
+  inline ios_base&
+  dec(ios_base& __base)
+  {
+    __base.setf(ios_base::dec, ios_base::basefield);
+    return __base;
+  }
+
+  /// Calls base.setf(ios_base::hex, ios_base::basefield).
+  inline ios_base&
+  hex(ios_base& __base)
+  {
+    __base.setf(ios_base::hex, ios_base::basefield);
+    return __base;
+  }
+
+  /// Calls base.setf(ios_base::oct, ios_base::basefield).
+  inline ios_base&
+  oct(ios_base& __base)
+  {
+    __base.setf(ios_base::oct, ios_base::basefield);
+    return __base;
+  }
+
+  // [27.4.5.4] floatfield manipulators
+  /// Calls base.setf(ios_base::fixed, ios_base::floatfield).
+  inline ios_base&
+  fixed(ios_base& __base)
+  {
+    __base.setf(ios_base::fixed, ios_base::floatfield);
+    return __base;
+  }
+
+  /// Calls base.setf(ios_base::scientific, ios_base::floatfield).
+  inline ios_base&
+  scientific(ios_base& __base)
+  {
+    __base.setf(ios_base::scientific, ios_base::floatfield);
+    return __base;
+  }
+
+#if __cplusplus >= 201103L
+  // New C++11 floatfield manipulators
+
+  /// Calls
+  /// base.setf(ios_base::fixed|ios_base::scientific, ios_base::floatfield)
+  inline ios_base&
+  hexfloat(ios_base& __base)
+  {
+    __base.setf(ios_base::fixed | ios_base::scientific, ios_base::floatfield);
+    return __base;
+  }
+
+  /// Calls @c base.unsetf(ios_base::floatfield)
+  inline ios_base&
+  defaultfloat(ios_base& __base)
+  {
+    __base.unsetf(ios_base::floatfield);
+    return __base;
+  }
+#endif
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif /* _IOS_BASE_H */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@ios_base.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@ios_base.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@istream.tcc b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@istream.tcc
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@istream.tcc
@@ -0,0 +1,1154 @@
+// istream classes -*- C++ -*-
+
+// Copyright (C) 1997-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/istream.tcc
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{istream}
+ */
+
+//
+// ISO C++ 14882: 27.6.1  Input streams
+//
+
+#ifndef _ISTREAM_TCC
+#define _ISTREAM_TCC 1
+
+#pragma GCC system_header
+
+#include <bits/cxxabi_forced.h>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  template<typename _CharT, typename _Traits>
+    basic_istream<_CharT, _Traits>::sentry::
+    sentry(basic_istream<_CharT, _Traits>& __in, bool __noskip) : _M_ok(false)
+    {
+      ios_base::iostate __err = ios_base::goodbit;
+      if (__in.good())
+	{
+	  __try
+	    {
+	      if (__in.tie())
+		__in.tie()->flush();
+	      if (!__noskip && bool(__in.flags() & ios_base::skipws))
+		{
+		  const __int_type __eof = traits_type::eof();
+		  __streambuf_type* __sb = __in.rdbuf();
+		  __int_type __c = __sb->sgetc();
+
+		  const __ctype_type& __ct = __check_facet(__in._M_ctype);
+		  while (!traits_type::eq_int_type(__c, __eof)
+			 && __ct.is(ctype_base::space,
+				    traits_type::to_char_type(__c)))
+		    __c = __sb->snextc();
+
+		  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+		  // 195. Should basic_istream::sentry's constructor ever
+		  // set eofbit?
+		  if (traits_type::eq_int_type(__c, __eof))
+		    __err |= ios_base::eofbit;
+		}
+	    }
+	  __catch(__cxxabiv1::__forced_unwind&)
+	    {
+	      __in._M_setstate(ios_base::badbit);
+	      __throw_exception_again;
+	    }
+	  __catch(...)
+	    { __in._M_setstate(ios_base::badbit); }
+	}
+
+      if (__in.good() && __err == ios_base::goodbit)
+	_M_ok = true;
+      else
+	{
+	  __err |= ios_base::failbit;
+	  __in.setstate(__err);
+	}
+    }
+
+  template<typename _CharT, typename _Traits>
+    template<typename _ValueT>
+      basic_istream<_CharT, _Traits>&
+      basic_istream<_CharT, _Traits>::
+      _M_extract(_ValueT& __v)
+      {
+	sentry __cerb(*this, false);
+	if (__cerb)
+	  {
+	    ios_base::iostate __err = ios_base::goodbit;
+	    __try
+	      {
+		const __num_get_type& __ng = __check_facet(this->_M_num_get);
+		__ng.get(*this, 0, *this, __err, __v);
+	      }
+	    __catch(__cxxabiv1::__forced_unwind&)
+	      {
+		this->_M_setstate(ios_base::badbit);
+		__throw_exception_again;
+	      }
+	    __catch(...)
+	      { this->_M_setstate(ios_base::badbit); }
+	    if (__err)
+	      this->setstate(__err);
+	  }
+	return *this;
+      }
+
+  template<typename _CharT, typename _Traits>
+    basic_istream<_CharT, _Traits>&
+    basic_istream<_CharT, _Traits>::
+    operator>>(short& __n)
+    {
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 118. basic_istream uses nonexistent num_get member functions.
+      sentry __cerb(*this, false);
+      if (__cerb)
+	{
+	  ios_base::iostate __err = ios_base::goodbit;
+	  __try
+	    {
+	      long __l;
+	      const __num_get_type& __ng = __check_facet(this->_M_num_get);
+	      __ng.get(*this, 0, *this, __err, __l);
+
+	      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+	      // 696. istream::operator>>(int&) broken.
+	      if (__l < __gnu_cxx::__numeric_traits<short>::__min)
+		{
+		  __err |= ios_base::failbit;
+		  __n = __gnu_cxx::__numeric_traits<short>::__min;
+		}
+	      else if (__l > __gnu_cxx::__numeric_traits<short>::__max)
+		{
+		  __err |= ios_base::failbit;
+		  __n = __gnu_cxx::__numeric_traits<short>::__max;
+		}
+	      else
+		__n = short(__l);
+	    }
+	  __catch(__cxxabiv1::__forced_unwind&)
+	    {
+	      this->_M_setstate(ios_base::badbit);
+	      __throw_exception_again;
+	    }
+	  __catch(...)
+	    { this->_M_setstate(ios_base::badbit); }
+	  if (__err)
+	    this->setstate(__err);
+	}
+      return *this;
+    }
+
+  template<typename _CharT, typename _Traits>
+    basic_istream<_CharT, _Traits>&
+    basic_istream<_CharT, _Traits>::
+    operator>>(int& __n)
+    {
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 118. basic_istream uses nonexistent num_get member functions.
+      sentry __cerb(*this, false);
+      if (__cerb)
+	{
+	  ios_base::iostate __err = ios_base::goodbit;
+	  __try
+	    {
+	      long __l;
+	      const __num_get_type& __ng = __check_facet(this->_M_num_get);
+	      __ng.get(*this, 0, *this, __err, __l);
+
+	      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+	      // 696. istream::operator>>(int&) broken.
+	      if (__l < __gnu_cxx::__numeric_traits<int>::__min)
+		{
+		  __err |= ios_base::failbit;
+		  __n = __gnu_cxx::__numeric_traits<int>::__min;
+		}
+	      else if (__l > __gnu_cxx::__numeric_traits<int>::__max)
+		{
+		  __err |= ios_base::failbit;	      
+		  __n = __gnu_cxx::__numeric_traits<int>::__max;
+		}
+	      else
+		__n = int(__l);
+	    }
+	  __catch(__cxxabiv1::__forced_unwind&)
+	    {
+	      this->_M_setstate(ios_base::badbit);
+	      __throw_exception_again;
+	    }
+	  __catch(...)
+	    { this->_M_setstate(ios_base::badbit); }
+	  if (__err)
+	    this->setstate(__err);
+	}
+      return *this;
+    }
+
+  template<typename _CharT, typename _Traits>
+    basic_istream<_CharT, _Traits>&
+    basic_istream<_CharT, _Traits>::
+    operator>>(__streambuf_type* __sbout)
+    {
+      ios_base::iostate __err = ios_base::goodbit;
+      sentry __cerb(*this, false);
+      if (__cerb && __sbout)
+	{
+	  __try
+	    {
+	      bool __ineof;
+	      if (!__copy_streambufs_eof(this->rdbuf(), __sbout, __ineof))
+		__err |= ios_base::failbit;
+	      if (__ineof)
+		__err |= ios_base::eofbit;
+	    }
+	  __catch(__cxxabiv1::__forced_unwind&)
+	    {
+	      this->_M_setstate(ios_base::failbit);
+	      __throw_exception_again;
+	    }
+	  __catch(...)
+	    { this->_M_setstate(ios_base::failbit); }
+	}
+      else if (!__sbout)
+	__err |= ios_base::failbit;
+      if (__err)
+	this->setstate(__err);
+      return *this;
+    }
+
+  template<typename _CharT, typename _Traits>
+    typename basic_istream<_CharT, _Traits>::int_type
+    basic_istream<_CharT, _Traits>::
+    get(void)
+    {
+      const int_type __eof = traits_type::eof();
+      int_type __c = __eof;
+      _M_gcount = 0;
+      ios_base::iostate __err = ios_base::goodbit;
+      sentry __cerb(*this, true);
+      if (__cerb)
+	{
+	  __try
+	    {
+	      __c = this->rdbuf()->sbumpc();
+	      // 27.6.1.1 paragraph 3
+	      if (!traits_type::eq_int_type(__c, __eof))
+		_M_gcount = 1;
+	      else
+		__err |= ios_base::eofbit;
+	    }
+	  __catch(__cxxabiv1::__forced_unwind&)
+	    {
+	      this->_M_setstate(ios_base::badbit);
+	      __throw_exception_again;
+	    }
+	  __catch(...)
+	    { this->_M_setstate(ios_base::badbit); }
+	}
+      if (!_M_gcount)
+	__err |= ios_base::failbit;
+      if (__err)
+	this->setstate(__err);
+      return __c;
+    }
+
+  template<typename _CharT, typename _Traits>
+    basic_istream<_CharT, _Traits>&
+    basic_istream<_CharT, _Traits>::
+    get(char_type& __c)
+    {
+      _M_gcount = 0;
+      ios_base::iostate __err = ios_base::goodbit;
+      sentry __cerb(*this, true);
+      if (__cerb)
+	{
+	  __try
+	    {
+	      const int_type __cb = this->rdbuf()->sbumpc();
+	      // 27.6.1.1 paragraph 3
+	      if (!traits_type::eq_int_type(__cb, traits_type::eof()))
+		{
+		  _M_gcount = 1;
+		  __c = traits_type::to_char_type(__cb);
+		}
+	      else
+		__err |= ios_base::eofbit;
+	    }
+	  __catch(__cxxabiv1::__forced_unwind&)
+	    {
+	      this->_M_setstate(ios_base::badbit);
+	      __throw_exception_again;
+	    }
+	  __catch(...)
+	    { this->_M_setstate(ios_base::badbit); }
+	}
+      if (!_M_gcount)
+	__err |= ios_base::failbit;
+      if (__err)
+	this->setstate(__err);
+      return *this;
+    }
+
+  template<typename _CharT, typename _Traits>
+    basic_istream<_CharT, _Traits>&
+    basic_istream<_CharT, _Traits>::
+    get(char_type* __s, streamsize __n, char_type __delim)
+    {
+      _M_gcount = 0;
+      ios_base::iostate __err = ios_base::goodbit;
+      sentry __cerb(*this, true);
+      if (__cerb)
+	{
+	  __try
+	    {
+	      const int_type __idelim = traits_type::to_int_type(__delim);
+	      const int_type __eof = traits_type::eof();
+	      __streambuf_type* __sb = this->rdbuf();
+	      int_type __c = __sb->sgetc();
+
+	      while (_M_gcount + 1 < __n
+		     && !traits_type::eq_int_type(__c, __eof)
+		     && !traits_type::eq_int_type(__c, __idelim))
+		{
+		  *__s++ = traits_type::to_char_type(__c);
+		  ++_M_gcount;
+		  __c = __sb->snextc();
+		}
+	      if (traits_type::eq_int_type(__c, __eof))
+		__err |= ios_base::eofbit;
+	    }
+	  __catch(__cxxabiv1::__forced_unwind&)
+	    {
+	      this->_M_setstate(ios_base::badbit);
+	      __throw_exception_again;
+	    }
+	  __catch(...)
+	    { this->_M_setstate(ios_base::badbit); }
+	}
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 243. get and getline when sentry reports failure.
+      if (__n > 0)
+	*__s = char_type();
+      if (!_M_gcount)
+	__err |= ios_base::failbit;
+      if (__err)
+	this->setstate(__err);
+      return *this;
+    }
+
+  template<typename _CharT, typename _Traits>
+    basic_istream<_CharT, _Traits>&
+    basic_istream<_CharT, _Traits>::
+    get(__streambuf_type& __sb, char_type __delim)
+    {
+      _M_gcount = 0;
+      ios_base::iostate __err = ios_base::goodbit;
+      sentry __cerb(*this, true);
+      if (__cerb)
+	{
+	  __try
+	    {
+	      const int_type __idelim = traits_type::to_int_type(__delim);
+	      const int_type __eof = traits_type::eof();
+	      __streambuf_type* __this_sb = this->rdbuf();
+	      int_type __c = __this_sb->sgetc();
+	      char_type __c2 = traits_type::to_char_type(__c);
+	      unsigned long long __gcount = 0;
+
+	      while (!traits_type::eq_int_type(__c, __eof)
+		     && !traits_type::eq_int_type(__c, __idelim)
+		     && !traits_type::eq_int_type(__sb.sputc(__c2), __eof))
+		{
+		  ++__gcount;
+		  __c = __this_sb->snextc();
+		  __c2 = traits_type::to_char_type(__c);
+		}
+	      if (traits_type::eq_int_type(__c, __eof))
+		__err |= ios_base::eofbit;
+	      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+	      // 3464. istream::gcount() can overflow
+	      if (__gcount <= __gnu_cxx::__numeric_traits<streamsize>::__max)
+		_M_gcount = __gcount;
+	      else
+		_M_gcount = __gnu_cxx::__numeric_traits<streamsize>::__max;
+	    }
+	  __catch(__cxxabiv1::__forced_unwind&)
+	    {
+	      this->_M_setstate(ios_base::badbit);
+	      __throw_exception_again;
+	    }
+	  __catch(...)
+	    { this->_M_setstate(ios_base::badbit); }
+	}
+      if (!_M_gcount)
+	__err |= ios_base::failbit;
+      if (__err)
+	this->setstate(__err);
+      return *this;
+    }
+
+  template<typename _CharT, typename _Traits>
+    basic_istream<_CharT, _Traits>&
+    basic_istream<_CharT, _Traits>::
+    getline(char_type* __s, streamsize __n, char_type __delim)
+    {
+      _M_gcount = 0;
+      ios_base::iostate __err = ios_base::goodbit;
+      sentry __cerb(*this, true);
+      if (__cerb)
+        {
+          __try
+            {
+              const int_type __idelim = traits_type::to_int_type(__delim);
+              const int_type __eof = traits_type::eof();
+              __streambuf_type* __sb = this->rdbuf();
+              int_type __c = __sb->sgetc();
+
+              while (_M_gcount + 1 < __n
+                     && !traits_type::eq_int_type(__c, __eof)
+                     && !traits_type::eq_int_type(__c, __idelim))
+                {
+                  *__s++ = traits_type::to_char_type(__c);
+                  __c = __sb->snextc();
+                  ++_M_gcount;
+                }
+              if (traits_type::eq_int_type(__c, __eof))
+                __err |= ios_base::eofbit;
+              else
+                {
+                  if (traits_type::eq_int_type(__c, __idelim))
+                    {
+                      __sb->sbumpc();
+                      ++_M_gcount;
+                    }
+                  else
+                    __err |= ios_base::failbit;
+                }
+            }
+	  __catch(__cxxabiv1::__forced_unwind&)
+	    {
+	      this->_M_setstate(ios_base::badbit);
+	      __throw_exception_again;
+	    }
+          __catch(...)
+            { this->_M_setstate(ios_base::badbit); }
+        }
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 243. get and getline when sentry reports failure.
+      if (__n > 0)
+	*__s = char_type();
+      if (!_M_gcount)
+        __err |= ios_base::failbit;
+      if (__err)
+        this->setstate(__err);
+      return *this;
+    }
+
+  // We provide three overloads, since the first two are much simpler
+  // than the general case. Also, the latter two can thus adopt the
+  // same "batchy" strategy used by getline above.
+  template<typename _CharT, typename _Traits>
+    basic_istream<_CharT, _Traits>&
+    basic_istream<_CharT, _Traits>::
+    ignore(void)
+    {
+      _M_gcount = 0;
+      sentry __cerb(*this, true);
+      if (__cerb)
+	{
+	  ios_base::iostate __err = ios_base::goodbit;
+	  __try
+	    {
+	      const int_type __eof = traits_type::eof();
+	      __streambuf_type* __sb = this->rdbuf();
+
+	      if (traits_type::eq_int_type(__sb->sbumpc(), __eof))
+		__err |= ios_base::eofbit;
+	      else
+		_M_gcount = 1;
+	    }
+	  __catch(__cxxabiv1::__forced_unwind&)
+	    {
+	      this->_M_setstate(ios_base::badbit);
+	      __throw_exception_again;
+	    }
+	  __catch(...)
+	    { this->_M_setstate(ios_base::badbit); }
+	  if (__err)
+	    this->setstate(__err);
+	}
+      return *this;
+    }
+
+  template<typename _CharT, typename _Traits>
+    basic_istream<_CharT, _Traits>&
+    basic_istream<_CharT, _Traits>::
+    ignore(streamsize __n)
+    {
+      _M_gcount = 0;
+      sentry __cerb(*this, true);
+      if (__cerb && __n > 0)
+        {
+          ios_base::iostate __err = ios_base::goodbit;
+          __try
+            {
+              const int_type __eof = traits_type::eof();
+              __streambuf_type* __sb = this->rdbuf();
+              int_type __c = __sb->sgetc();
+
+	      // N.B. On LFS-enabled platforms streamsize is still 32 bits
+	      // wide: if we want to implement the standard mandated behavior
+	      // for n == max() (see 27.6.1.3/24) we are at risk of signed
+	      // integer overflow: thus these contortions. Also note that,
+	      // by definition, when more than 2G chars are actually ignored,
+	      // _M_gcount (the return value of gcount, that is) cannot be
+	      // really correct, being unavoidably too small.
+	      bool __large_ignore = false;
+	      while (true)
+		{
+		  while (_M_gcount < __n
+			 && !traits_type::eq_int_type(__c, __eof))
+		    {
+		      ++_M_gcount;
+		      __c = __sb->snextc();
+		    }
+		  if (__n == __gnu_cxx::__numeric_traits<streamsize>::__max
+		      && !traits_type::eq_int_type(__c, __eof))
+		    {
+		      _M_gcount =
+			__gnu_cxx::__numeric_traits<streamsize>::__min;
+		      __large_ignore = true;
+		    }
+		  else
+		    break;
+		}
+
+	      if (__n == __gnu_cxx::__numeric_traits<streamsize>::__max)
+		{
+		  if (__large_ignore)
+		    _M_gcount = __gnu_cxx::__numeric_traits<streamsize>::__max;
+
+		  if (traits_type::eq_int_type(__c, __eof))
+		    __err |= ios_base::eofbit;
+		}
+	      else if (_M_gcount < __n)
+		{
+		  if (traits_type::eq_int_type(__c, __eof))
+		    __err |= ios_base::eofbit;
+		}
+            }
+	  __catch(__cxxabiv1::__forced_unwind&)
+	    {
+	      this->_M_setstate(ios_base::badbit);
+	      __throw_exception_again;
+	    }
+          __catch(...)
+            { this->_M_setstate(ios_base::badbit); }
+          if (__err)
+            this->setstate(__err);
+        }
+      return *this;
+    }
+
+  template<typename _CharT, typename _Traits>
+    basic_istream<_CharT, _Traits>&
+    basic_istream<_CharT, _Traits>::
+    ignore(streamsize __n, int_type __delim)
+    {
+      _M_gcount = 0;
+      sentry __cerb(*this, true);
+      if (__cerb && __n > 0)
+        {
+          ios_base::iostate __err = ios_base::goodbit;
+          __try
+            {
+              const int_type __eof = traits_type::eof();
+              __streambuf_type* __sb = this->rdbuf();
+              int_type __c = __sb->sgetc();
+
+	      // See comment above.
+	      bool __large_ignore = false;
+	      while (true)
+		{
+		  while (_M_gcount < __n
+			 && !traits_type::eq_int_type(__c, __eof)
+			 && !traits_type::eq_int_type(__c, __delim))
+		    {
+		      ++_M_gcount;
+		      __c = __sb->snextc();
+		    }
+		  if (__n == __gnu_cxx::__numeric_traits<streamsize>::__max
+		      && !traits_type::eq_int_type(__c, __eof)
+		      && !traits_type::eq_int_type(__c, __delim))
+		    {
+		      _M_gcount =
+			__gnu_cxx::__numeric_traits<streamsize>::__min;
+		      __large_ignore = true;
+		    }
+		  else
+		    break;
+		}
+
+	      if (__n == __gnu_cxx::__numeric_traits<streamsize>::__max)
+		{
+		  if (__large_ignore)
+		    _M_gcount = __gnu_cxx::__numeric_traits<streamsize>::__max;
+
+		  if (traits_type::eq_int_type(__c, __eof))
+		    __err |= ios_base::eofbit;
+		  else
+		    {
+		      if (_M_gcount != __n)
+			++_M_gcount;
+		      __sb->sbumpc();
+		    }
+		}
+	      else if (_M_gcount < __n) // implies __c == __delim or EOF
+		{
+		  if (traits_type::eq_int_type(__c, __eof))
+		    __err |= ios_base::eofbit;
+		  else
+		    {
+		      ++_M_gcount;
+		      __sb->sbumpc();
+		    }
+		}
+            }
+	  __catch(__cxxabiv1::__forced_unwind&)
+	    {
+	      this->_M_setstate(ios_base::badbit);
+	      __throw_exception_again;
+	    }
+          __catch(...)
+            { this->_M_setstate(ios_base::badbit); }
+          if (__err)
+            this->setstate(__err);
+        }
+      return *this;
+    }
+
+  template<typename _CharT, typename _Traits>
+    typename basic_istream<_CharT, _Traits>::int_type
+    basic_istream<_CharT, _Traits>::
+    peek(void)
+    {
+      int_type __c = traits_type::eof();
+      _M_gcount = 0;
+      sentry __cerb(*this, true);
+      if (__cerb)
+	{
+	  ios_base::iostate __err = ios_base::goodbit;
+	  __try
+	    {
+	      __c = this->rdbuf()->sgetc();
+	      if (traits_type::eq_int_type(__c, traits_type::eof()))
+		__err |= ios_base::eofbit;
+	    }
+	  __catch(__cxxabiv1::__forced_unwind&)
+	    {
+	      this->_M_setstate(ios_base::badbit);
+	      __throw_exception_again;
+	    }
+	  __catch(...)
+	    { this->_M_setstate(ios_base::badbit); }
+	  if (__err)
+	    this->setstate(__err);
+	}
+      return __c;
+    }
+
+  template<typename _CharT, typename _Traits>
+    basic_istream<_CharT, _Traits>&
+    basic_istream<_CharT, _Traits>::
+    read(char_type* __s, streamsize __n)
+    {
+      _M_gcount = 0;
+      sentry __cerb(*this, true);
+      if (__cerb)
+	{
+	  ios_base::iostate __err = ios_base::goodbit;
+	  __try
+	    {
+	      _M_gcount = this->rdbuf()->sgetn(__s, __n);
+	      if (_M_gcount != __n)
+		__err |= (ios_base::eofbit | ios_base::failbit);
+	    }
+	  __catch(__cxxabiv1::__forced_unwind&)
+	    {
+	      this->_M_setstate(ios_base::badbit);
+	      __throw_exception_again;
+	    }
+	  __catch(...)
+	    { this->_M_setstate(ios_base::badbit); }
+	  if (__err)
+	    this->setstate(__err);
+	}
+      return *this;
+    }
+
+  template<typename _CharT, typename _Traits>
+    streamsize
+    basic_istream<_CharT, _Traits>::
+    readsome(char_type* __s, streamsize __n)
+    {
+      _M_gcount = 0;
+      sentry __cerb(*this, true);
+      if (__cerb)
+	{
+	  ios_base::iostate __err = ios_base::goodbit;
+	  __try
+	    {
+	      // Cannot compare int_type with streamsize generically.
+	      const streamsize __num = this->rdbuf()->in_avail();
+	      if (__num > 0)
+		_M_gcount = this->rdbuf()->sgetn(__s, std::min(__num, __n));
+	      else if (__num == -1)
+		__err |= ios_base::eofbit;
+	    }
+	  __catch(__cxxabiv1::__forced_unwind&)
+	    {
+	      this->_M_setstate(ios_base::badbit);
+	      __throw_exception_again;
+	    }
+	  __catch(...)
+	    { this->_M_setstate(ios_base::badbit); }
+	  if (__err)
+	    this->setstate(__err);
+	}
+      return _M_gcount;
+    }
+
+  template<typename _CharT, typename _Traits>
+    basic_istream<_CharT, _Traits>&
+    basic_istream<_CharT, _Traits>::
+    putback(char_type __c)
+    {
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 60. What is a formatted input function?
+      _M_gcount = 0;
+      // Clear eofbit per N3168.
+      this->clear(this->rdstate() & ~ios_base::eofbit);
+      sentry __cerb(*this, true);
+      if (__cerb)
+	{
+	  ios_base::iostate __err = ios_base::goodbit;
+	  __try
+	    {
+	      const int_type __eof = traits_type::eof();
+	      __streambuf_type* __sb = this->rdbuf();
+	      if (!__sb
+		  || traits_type::eq_int_type(__sb->sputbackc(__c), __eof))
+		__err |= ios_base::badbit;
+	    }
+	  __catch(__cxxabiv1::__forced_unwind&)
+	    {
+	      this->_M_setstate(ios_base::badbit);
+	      __throw_exception_again;
+	    }
+	  __catch(...)
+	    { this->_M_setstate(ios_base::badbit); }
+	  if (__err)
+	    this->setstate(__err);
+	}
+      return *this;
+    }
+
+  template<typename _CharT, typename _Traits>
+    basic_istream<_CharT, _Traits>&
+    basic_istream<_CharT, _Traits>::
+    unget(void)
+    {
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 60. What is a formatted input function?
+      _M_gcount = 0;
+      // Clear eofbit per N3168.
+      this->clear(this->rdstate() & ~ios_base::eofbit);
+      sentry __cerb(*this, true);
+      if (__cerb)
+	{
+	  ios_base::iostate __err = ios_base::goodbit;
+	  __try
+	    {
+	      const int_type __eof = traits_type::eof();
+	      __streambuf_type* __sb = this->rdbuf();
+	      if (!__sb
+		  || traits_type::eq_int_type(__sb->sungetc(), __eof))
+		__err |= ios_base::badbit;
+	    }
+	  __catch(__cxxabiv1::__forced_unwind&)
+	    {
+	      this->_M_setstate(ios_base::badbit);
+	      __throw_exception_again;
+	    }
+	  __catch(...)
+	    { this->_M_setstate(ios_base::badbit); }
+	  if (__err)
+	    this->setstate(__err);
+	}
+      return *this;
+    }
+
+  template<typename _CharT, typename _Traits>
+    int
+    basic_istream<_CharT, _Traits>::
+    sync(void)
+    {
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // DR60.  Do not change _M_gcount.
+      int __ret = -1;
+      sentry __cerb(*this, true);
+      if (__cerb)
+	{
+	  ios_base::iostate __err = ios_base::goodbit;
+	  __try
+	    {
+	      __streambuf_type* __sb = this->rdbuf();
+	      if (__sb)
+		{
+		  if (__sb->pubsync() == -1)
+		    __err |= ios_base::badbit;
+		  else
+		    __ret = 0;
+		}
+	    }
+	  __catch(__cxxabiv1::__forced_unwind&)
+	    {
+	      this->_M_setstate(ios_base::badbit);
+	      __throw_exception_again;
+	    }
+	  __catch(...)
+	    { this->_M_setstate(ios_base::badbit); }
+	  if (__err)
+	    this->setstate(__err);
+	}
+      return __ret;
+    }
+
+  template<typename _CharT, typename _Traits>
+    typename basic_istream<_CharT, _Traits>::pos_type
+    basic_istream<_CharT, _Traits>::
+    tellg(void)
+    {
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // DR60.  Do not change _M_gcount.
+      pos_type __ret = pos_type(-1);
+      sentry __cerb(*this, true);
+      if (__cerb)
+	{
+	  __try
+	    {
+	      if (!this->fail())
+		__ret = this->rdbuf()->pubseekoff(0, ios_base::cur,
+						  ios_base::in);
+	    }
+	  __catch(__cxxabiv1::__forced_unwind&)
+	    {
+	      this->_M_setstate(ios_base::badbit);
+	      __throw_exception_again;
+	    }
+	  __catch(...)
+	    { this->_M_setstate(ios_base::badbit); }
+	}
+      return __ret;
+    }
+
+  template<typename _CharT, typename _Traits>
+    basic_istream<_CharT, _Traits>&
+    basic_istream<_CharT, _Traits>::
+    seekg(pos_type __pos)
+    {
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // DR60.  Do not change _M_gcount.
+      // Clear eofbit per N3168.
+      this->clear(this->rdstate() & ~ios_base::eofbit);
+      sentry __cerb(*this, true);
+      if (__cerb)
+	{
+	  ios_base::iostate __err = ios_base::goodbit;
+	  __try
+	    {
+	      if (!this->fail())
+		{
+		  // 136.  seekp, seekg setting wrong streams?
+		  const pos_type __p = this->rdbuf()->pubseekpos(__pos,
+								 ios_base::in);
+		  
+		  // 129.  Need error indication from seekp() and seekg()
+		  if (__p == pos_type(off_type(-1)))
+		    __err |= ios_base::failbit;
+		}
+	    }
+	  __catch(__cxxabiv1::__forced_unwind&)
+	    {
+	      this->_M_setstate(ios_base::badbit);
+	      __throw_exception_again;
+	    }
+	  __catch(...)
+	    { this->_M_setstate(ios_base::badbit); }
+	  if (__err)
+	    this->setstate(__err);
+	}
+      return *this;
+    }
+
+  template<typename _CharT, typename _Traits>
+    basic_istream<_CharT, _Traits>&
+    basic_istream<_CharT, _Traits>::
+    seekg(off_type __off, ios_base::seekdir __dir)
+    {
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // DR60.  Do not change _M_gcount.
+      // Clear eofbit per N3168.
+      this->clear(this->rdstate() & ~ios_base::eofbit);
+      sentry __cerb(*this, true);
+      if (__cerb)
+	{
+	  ios_base::iostate __err = ios_base::goodbit;
+	  __try
+	    {
+	      if (!this->fail())
+		{
+		  // 136.  seekp, seekg setting wrong streams?
+		  const pos_type __p = this->rdbuf()->pubseekoff(__off, __dir,
+								 ios_base::in);
+	      
+		  // 129.  Need error indication from seekp() and seekg()
+		  if (__p == pos_type(off_type(-1)))
+		    __err |= ios_base::failbit;
+		}
+	    }
+	  __catch(__cxxabiv1::__forced_unwind&)
+	    {
+	      this->_M_setstate(ios_base::badbit);
+	      __throw_exception_again;
+	    }
+	  __catch(...)
+	    { this->_M_setstate(ios_base::badbit); }
+	  if (__err)
+	    this->setstate(__err);
+	}
+      return *this;
+    }
+
+  // 27.6.1.2.3 Character extraction templates
+  template<typename _CharT, typename _Traits>
+    basic_istream<_CharT, _Traits>&
+    operator>>(basic_istream<_CharT, _Traits>& __in, _CharT& __c)
+    {
+      typedef basic_istream<_CharT, _Traits>		__istream_type;
+      typedef typename __istream_type::int_type         __int_type;
+
+      typename __istream_type::sentry __cerb(__in, false);
+      if (__cerb)
+	{
+	  ios_base::iostate __err = ios_base::goodbit;
+	  __try
+	    {
+	      const __int_type __cb = __in.rdbuf()->sbumpc();
+	      if (!_Traits::eq_int_type(__cb, _Traits::eof()))
+		__c = _Traits::to_char_type(__cb);
+	      else
+		__err |= (ios_base::eofbit | ios_base::failbit);
+	    }
+	  __catch(__cxxabiv1::__forced_unwind&)
+	    {
+	      __in._M_setstate(ios_base::badbit);
+	      __throw_exception_again;
+	    }
+	  __catch(...)
+	    { __in._M_setstate(ios_base::badbit); }
+	  if (__err)
+	    __in.setstate(__err);
+	}
+      return __in;
+    }
+
+  template<typename _CharT, typename _Traits>
+    void
+    __istream_extract(basic_istream<_CharT, _Traits>& __in, _CharT* __s,
+		      streamsize __num)
+    {
+      typedef basic_istream<_CharT, _Traits>		__istream_type;
+      typedef basic_streambuf<_CharT, _Traits>          __streambuf_type;
+      typedef typename _Traits::int_type		int_type;
+      typedef _CharT					char_type;
+      typedef ctype<_CharT>				__ctype_type;
+
+      streamsize __extracted = 0;
+      ios_base::iostate __err = ios_base::goodbit;
+      typename __istream_type::sentry __cerb(__in, false);
+      if (__cerb)
+	{
+	  __try
+	    {
+	      // Figure out how many characters to extract.
+	      streamsize __width = __in.width();
+	      if (0 < __width && __width < __num)
+		__num = __width;
+
+	      const __ctype_type& __ct = use_facet<__ctype_type>(__in.getloc());
+
+	      const int_type __eof = _Traits::eof();
+	      __streambuf_type* __sb = __in.rdbuf();
+	      int_type __c = __sb->sgetc();
+
+	      while (__extracted < __num - 1
+		     && !_Traits::eq_int_type(__c, __eof)
+		     && !__ct.is(ctype_base::space,
+				 _Traits::to_char_type(__c)))
+		{
+		  *__s++ = _Traits::to_char_type(__c);
+		  ++__extracted;
+		  __c = __sb->snextc();
+		}
+
+	      if (__extracted < __num - 1
+		  && _Traits::eq_int_type(__c, __eof))
+		__err |= ios_base::eofbit;
+
+	      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+	      // 68.  Extractors for char* should store null at end
+	      *__s = char_type();
+	      __in.width(0);
+	    }
+	  __catch(__cxxabiv1::__forced_unwind&)
+	    {
+	      __in._M_setstate(ios_base::badbit);
+	      __throw_exception_again;
+	    }
+	  __catch(...)
+	    { __in._M_setstate(ios_base::badbit); }
+	}
+      if (!__extracted)
+	__err |= ios_base::failbit;
+      if (__err)
+	__in.setstate(__err);
+    }
+
+  // 27.6.1.4 Standard basic_istream manipulators
+  template<typename _CharT, typename _Traits>
+    basic_istream<_CharT, _Traits>&
+    ws(basic_istream<_CharT, _Traits>& __in)
+    {
+      typedef basic_istream<_CharT, _Traits>		__istream_type;
+      typedef basic_streambuf<_CharT, _Traits>          __streambuf_type;
+      typedef typename __istream_type::int_type		__int_type;
+      typedef ctype<_CharT>				__ctype_type;
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 451. behavior of std::ws
+      typename __istream_type::sentry __cerb(__in, true);
+      if (__cerb)
+	{
+	  ios_base::iostate __err = ios_base::goodbit;
+	  __try
+	    {
+	      const __ctype_type& __ct = use_facet<__ctype_type>(__in.getloc());
+	      const __int_type __eof = _Traits::eof();
+	      __streambuf_type* __sb = __in.rdbuf();
+	      __int_type __c = __sb->sgetc();
+
+	      while (true)
+		{
+		  if (_Traits::eq_int_type(__c, __eof))
+		    {
+		      __err = ios_base::eofbit;
+		      break;
+		    }
+		  if (!__ct.is(ctype_base::space, _Traits::to_char_type(__c)))
+		    break;
+		  __c = __sb->snextc();
+		}
+	    }
+	  __catch (const __cxxabiv1::__forced_unwind&)
+	    {
+	      __in._M_setstate(ios_base::badbit);
+	      __throw_exception_again;
+	    }
+	  __catch (...)
+	    {
+	      __in._M_setstate(ios_base::badbit);
+	    }
+	  if (__err)
+	    __in.setstate(__err);
+	}
+      return __in;
+    }
+
+  // Inhibit implicit instantiations for required instantiations,
+  // which are defined via explicit instantiations elsewhere.
+#if _GLIBCXX_EXTERN_TEMPLATE
+  extern template class basic_istream<char>;
+  extern template istream& ws(istream&);
+  extern template istream& operator>>(istream&, char&);
+  extern template istream& operator>>(istream&, unsigned char&);
+  extern template istream& operator>>(istream&, signed char&);
+
+  extern template istream& istream::_M_extract(unsigned short&);
+  extern template istream& istream::_M_extract(unsigned int&);  
+  extern template istream& istream::_M_extract(long&);
+  extern template istream& istream::_M_extract(unsigned long&);
+  extern template istream& istream::_M_extract(bool&);
+#ifdef _GLIBCXX_USE_LONG_LONG
+  extern template istream& istream::_M_extract(long long&);
+  extern template istream& istream::_M_extract(unsigned long long&);
+#endif
+  extern template istream& istream::_M_extract(float&);
+  extern template istream& istream::_M_extract(double&);
+  extern template istream& istream::_M_extract(long double&);
+  extern template istream& istream::_M_extract(void*&);
+
+  extern template class basic_iostream<char>;
+
+#ifdef _GLIBCXX_USE_WCHAR_T
+  extern template class basic_istream<wchar_t>;
+  extern template wistream& ws(wistream&);
+  extern template wistream& operator>>(wistream&, wchar_t&);
+  extern template void __istream_extract(wistream&, wchar_t*, streamsize);
+
+  extern template wistream& wistream::_M_extract(unsigned short&);
+  extern template wistream& wistream::_M_extract(unsigned int&);  
+  extern template wistream& wistream::_M_extract(long&);
+  extern template wistream& wistream::_M_extract(unsigned long&);
+  extern template wistream& wistream::_M_extract(bool&);
+#ifdef _GLIBCXX_USE_LONG_LONG
+  extern template wistream& wistream::_M_extract(long long&);
+  extern template wistream& wistream::_M_extract(unsigned long long&);
+#endif
+  extern template wistream& wistream::_M_extract(float&);
+  extern template wistream& wistream::_M_extract(double&);
+  extern template wistream& wistream::_M_extract(long double&);
+  extern template wistream& wistream::_M_extract(void*&);
+
+  extern template class basic_iostream<wchar_t>;
+#endif
+#endif
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@istream.tcc.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@istream.tcc.blob
new file mode 100644
index 0000000000000000000000000000000000000000..df4578959922161b271b5a1bff53d3e76b6a49e2
Binary files /dev/null and b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@istream.tcc.blob differ
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@list.tcc b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@list.tcc
new file mode 100644
index 0000000000000000000000000000000000000000..d6b6e975ff5b3eb4a40fc0261060c7664a8a0adf
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@list.tcc
@@ -0,0 +1,669 @@
+// List implementation (out of line) -*- C++ -*-
+
+// Copyright (C) 2001-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/*
+ *
+ * Copyright (c) 1994
+ * Hewlett-Packard Company
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Hewlett-Packard Company makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ *
+ *
+ * Copyright (c) 1996,1997
+ * Silicon Graphics Computer Systems, Inc.
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Silicon Graphics makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ */
+
+/** @file bits/list.tcc
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{list}
+ */
+
+#ifndef _LIST_TCC
+#define _LIST_TCC 1
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+_GLIBCXX_BEGIN_NAMESPACE_CONTAINER
+
+  template<typename _Tp, typename _Alloc>
+    void
+    _List_base<_Tp, _Alloc>::
+    _M_clear() _GLIBCXX_NOEXCEPT
+    {
+      typedef _List_node<_Tp>  _Node;
+      __detail::_List_node_base* __cur = _M_impl._M_node._M_next;
+      while (__cur != &_M_impl._M_node)
+	{
+	  _Node* __tmp = static_cast<_Node*>(__cur);
+	  __cur = __tmp->_M_next;
+	  _Tp* __val = __tmp->_M_valptr();
+#if __cplusplus >= 201103L
+	  _Node_alloc_traits::destroy(_M_get_Node_allocator(), __val);
+#else
+	  _Tp_alloc_type(_M_get_Node_allocator()).destroy(__val);
+#endif
+	  _M_put_node(__tmp);
+	}
+    }
+
+#if __cplusplus >= 201103L
+  template<typename _Tp, typename _Alloc>
+    template<typename... _Args>
+      typename list<_Tp, _Alloc>::iterator
+      list<_Tp, _Alloc>::
+      emplace(const_iterator __position, _Args&&... __args)
+      {
+	_Node* __tmp = _M_create_node(std::forward<_Args>(__args)...);
+	__tmp->_M_hook(__position._M_const_cast()._M_node);
+	this->_M_inc_size(1);
+	return iterator(__tmp);
+      }
+#endif
+
+  template<typename _Tp, typename _Alloc>
+    typename list<_Tp, _Alloc>::iterator
+    list<_Tp, _Alloc>::
+#if __cplusplus >= 201103L
+    insert(const_iterator __position, const value_type& __x)
+#else
+    insert(iterator __position, const value_type& __x)
+#endif
+    {
+      _Node* __tmp = _M_create_node(__x);
+      __tmp->_M_hook(__position._M_const_cast()._M_node);
+      this->_M_inc_size(1);
+      return iterator(__tmp);
+    }
+
+#if __cplusplus >= 201103L
+  template<typename _Tp, typename _Alloc>
+    typename list<_Tp, _Alloc>::iterator
+    list<_Tp, _Alloc>::
+    insert(const_iterator __position, size_type __n, const value_type& __x)
+    {
+      if (__n)
+	{
+	  list __tmp(__n, __x, get_allocator());
+	  iterator __it = __tmp.begin();
+	  splice(__position, __tmp);
+	  return __it;
+	}
+      return __position._M_const_cast();
+    }
+
+  template<typename _Tp, typename _Alloc>
+    template<typename _InputIterator, typename>
+      typename list<_Tp, _Alloc>::iterator
+      list<_Tp, _Alloc>::
+      insert(const_iterator __position, _InputIterator __first,
+	     _InputIterator __last)
+      {
+	list __tmp(__first, __last, get_allocator());
+	if (!__tmp.empty())
+	  {
+	    iterator __it = __tmp.begin();
+	    splice(__position, __tmp);
+	    return __it;
+	  }
+	return __position._M_const_cast();
+      }
+#endif
+
+  template<typename _Tp, typename _Alloc>
+    typename list<_Tp, _Alloc>::iterator
+    list<_Tp, _Alloc>::
+#if __cplusplus >= 201103L
+    erase(const_iterator __position) noexcept
+#else
+    erase(iterator __position)
+#endif
+    {
+      iterator __ret = iterator(__position._M_node->_M_next);
+      _M_erase(__position._M_const_cast());
+      return __ret;
+    }
+
+  // Return a const_iterator indicating the position to start inserting or
+  // erasing elements (depending whether the list is growing or shrinking),
+  // and set __new_size to the number of new elements that must be appended.
+  // Equivalent to the following, but performed optimally:
+  // if (__new_size < size()) {
+  //   __new_size = 0;
+  //   return std::next(begin(), __new_size);
+  // } else {
+  //   __newsize -= size();
+  //   return end();
+  // }
+  template<typename _Tp, typename _Alloc>
+    typename list<_Tp, _Alloc>::const_iterator
+    list<_Tp, _Alloc>::
+    _M_resize_pos(size_type& __new_size) const
+    {
+      const_iterator __i;
+#if _GLIBCXX_USE_CXX11_ABI
+      const size_type __len = size();
+      if (__new_size < __len)
+	{
+	  if (__new_size <= __len / 2)
+	    {
+	      __i = begin();
+	      std::advance(__i, __new_size);
+	    }
+	  else
+	    {
+	      __i = end();
+	      ptrdiff_t __num_erase = __len - __new_size;
+	      std::advance(__i, -__num_erase);
+	    }
+	  __new_size = 0;
+	  return __i;
+	}
+      else
+	__i = end();
+#else
+      size_type __len = 0;
+      for (__i = begin(); __i != end() && __len < __new_size; ++__i, ++__len)
+        ;
+#endif
+      __new_size -= __len;
+      return __i;
+    }
+
+#if __cplusplus >= 201103L
+  template<typename _Tp, typename _Alloc>
+    void
+    list<_Tp, _Alloc>::
+    _M_default_append(size_type __n)
+    {
+      size_type __i = 0;
+      __try
+	{
+	  for (; __i < __n; ++__i)
+	    emplace_back();
+	}
+      __catch(...)
+	{
+	  for (; __i; --__i)
+	    pop_back();
+	  __throw_exception_again;
+	}
+    }
+
+  template<typename _Tp, typename _Alloc>
+    void
+    list<_Tp, _Alloc>::
+    resize(size_type __new_size)
+    {
+      const_iterator __i = _M_resize_pos(__new_size);
+      if (__new_size)
+	_M_default_append(__new_size);
+      else
+        erase(__i, end());
+    }
+
+  template<typename _Tp, typename _Alloc>
+    void
+    list<_Tp, _Alloc>::
+    resize(size_type __new_size, const value_type& __x)
+    {
+      const_iterator __i = _M_resize_pos(__new_size);
+      if (__new_size)
+        insert(end(), __new_size, __x);
+      else
+        erase(__i, end());
+    }
+#else
+  template<typename _Tp, typename _Alloc>
+    void
+    list<_Tp, _Alloc>::
+    resize(size_type __new_size, value_type __x)
+    {
+      const_iterator __i = _M_resize_pos(__new_size);
+      if (__new_size)
+        insert(end(), __new_size, __x);
+      else
+        erase(__i._M_const_cast(), end());
+    }
+#endif
+
+  template<typename _Tp, typename _Alloc>
+    list<_Tp, _Alloc>&
+    list<_Tp, _Alloc>::
+    operator=(const list& __x)
+    {
+      if (this != std::__addressof(__x))
+	{
+#if __cplusplus >= 201103L
+	  if (_Node_alloc_traits::_S_propagate_on_copy_assign())
+	    {
+              auto& __this_alloc = this->_M_get_Node_allocator();
+              auto& __that_alloc = __x._M_get_Node_allocator();
+              if (!_Node_alloc_traits::_S_always_equal()
+	          && __this_alloc != __that_alloc)
+	        {
+		  // replacement allocator cannot free existing storage
+		  clear();
+		}
+	      std::__alloc_on_copy(__this_alloc, __that_alloc);
+            }
+#endif
+	  _M_assign_dispatch(__x.begin(), __x.end(), __false_type());
+	}
+      return *this;
+    }
+
+  template<typename _Tp, typename _Alloc>
+    void
+    list<_Tp, _Alloc>::
+    _M_fill_assign(size_type __n, const value_type& __val)
+    {
+      iterator __i = begin();
+      for (; __i != end() && __n > 0; ++__i, --__n)
+        *__i = __val;
+      if (__n > 0)
+        insert(end(), __n, __val);
+      else
+        erase(__i, end());
+    }
+
+  template<typename _Tp, typename _Alloc>
+    template <typename _InputIterator>
+      void
+      list<_Tp, _Alloc>::
+      _M_assign_dispatch(_InputIterator __first2, _InputIterator __last2,
+			 __false_type)
+      {
+        iterator __first1 = begin();
+        iterator __last1 = end();
+        for (; __first1 != __last1 && __first2 != __last2;
+	     ++__first1, (void)++__first2)
+          *__first1 = *__first2;
+        if (__first2 == __last2)
+          erase(__first1, __last1);
+        else
+          insert(__last1, __first2, __last2);
+      }
+
+#if __cplusplus > 201703L
+# define _GLIBCXX20_ONLY(__expr) __expr
+#else
+# define _GLIBCXX20_ONLY(__expr)
+#endif
+
+  template<typename _Tp, typename _Alloc>
+    typename list<_Tp, _Alloc>::__remove_return_type
+    list<_Tp, _Alloc>::
+    remove(const value_type& __value)
+    {
+#if !_GLIBCXX_USE_CXX11_ABI
+      size_type __removed __attribute__((__unused__)) = 0;
+#endif
+      list __to_destroy(get_allocator());
+      iterator __first = begin();
+      iterator __last = end();
+      while (__first != __last)
+	{
+	  iterator __next = __first;
+	  ++__next;
+	  if (*__first == __value)
+	    {
+	      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+	      // 526. Is it undefined if a function in the standard changes
+	      // in parameters?
+	      __to_destroy.splice(__to_destroy.begin(), *this, __first);
+#if !_GLIBCXX_USE_CXX11_ABI
+	      _GLIBCXX20_ONLY( __removed++ );
+#endif
+	    }
+
+	  __first = __next;
+	}
+
+#if !_GLIBCXX_USE_CXX11_ABI
+	return _GLIBCXX20_ONLY( __removed );
+#else
+	return _GLIBCXX20_ONLY( __to_destroy.size() );
+#endif
+    }
+
+  template<typename _Tp, typename _Alloc>
+    typename list<_Tp, _Alloc>::__remove_return_type
+    list<_Tp, _Alloc>::
+    unique()
+    {
+      iterator __first = begin();
+      iterator __last = end();
+      if (__first == __last)
+	return _GLIBCXX20_ONLY( 0 );
+#if !_GLIBCXX_USE_CXX11_ABI
+      size_type __removed __attribute__((__unused__)) = 0;
+#endif
+      list __to_destroy(get_allocator());
+      iterator __next = __first;
+      while (++__next != __last)
+	{
+	  if (*__first == *__next)
+	    {
+	      __to_destroy.splice(__to_destroy.begin(), *this, __next);
+#if !_GLIBCXX_USE_CXX11_ABI
+	      _GLIBCXX20_ONLY( __removed++ );
+#endif
+	    }
+	  else
+	    __first = __next;
+	  __next = __first;
+	}
+
+#if !_GLIBCXX_USE_CXX11_ABI
+      return _GLIBCXX20_ONLY( __removed );
+#else
+      return _GLIBCXX20_ONLY( __to_destroy.size() );
+#endif
+    }
+
+  template<typename _Tp, typename _Alloc>
+    void
+    list<_Tp, _Alloc>::
+#if __cplusplus >= 201103L
+    merge(list&& __x)
+#else
+    merge(list& __x)
+#endif
+    {
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 300. list::merge() specification incomplete
+      if (this != std::__addressof(__x))
+	{
+	  _M_check_equal_allocators(__x);
+
+	  iterator __first1 = begin();
+	  iterator __last1 = end();
+	  iterator __first2 = __x.begin();
+	  iterator __last2 = __x.end();
+
+	  const _Finalize_merge __fin(*this, __x, __first2);
+
+	  while (__first1 != __last1 && __first2 != __last2)
+	    if (*__first2 < *__first1)
+	      {
+		iterator __next = __first2;
+		_M_transfer(__first1, __first2, ++__next);
+		__first2 = __next;
+	      }
+	    else
+	      ++__first1;
+	  if (__first2 != __last2)
+	    {
+	      _M_transfer(__last1, __first2, __last2);
+	      __first2 = __last2;
+	    }
+	}
+    }
+
+  template<typename _Tp, typename _Alloc>
+    template <typename _StrictWeakOrdering>
+      void
+      list<_Tp, _Alloc>::
+#if __cplusplus >= 201103L
+      merge(list&& __x, _StrictWeakOrdering __comp)
+#else
+      merge(list& __x, _StrictWeakOrdering __comp)
+#endif
+      {
+	// _GLIBCXX_RESOLVE_LIB_DEFECTS
+	// 300. list::merge() specification incomplete
+	if (this != std::__addressof(__x))
+	  {
+	    _M_check_equal_allocators(__x);
+
+	    iterator __first1 = begin();
+	    iterator __last1 = end();
+	    iterator __first2 = __x.begin();
+	    iterator __last2 = __x.end();
+
+	    const _Finalize_merge __fin(*this, __x, __first2);
+
+	    while (__first1 != __last1 && __first2 != __last2)
+	      if (__comp(*__first2, *__first1))
+		{
+		  iterator __next = __first2;
+		  _M_transfer(__first1, __first2, ++__next);
+		  __first2 = __next;
+		}
+	      else
+		++__first1;
+	    if (__first2 != __last2)
+	      {
+		_M_transfer(__last1, __first2, __last2);
+		__first2 = __last2;
+	      }
+	  }
+      }
+
+  template<typename _Tp, typename _Alloc>
+    void
+    list<_Tp, _Alloc>::
+    sort()
+    {
+      // Do nothing if the list has length 0 or 1.
+      if (this->_M_impl._M_node._M_next != &this->_M_impl._M_node
+	  && this->_M_impl._M_node._M_next->_M_next != &this->_M_impl._M_node)
+      {
+	using __detail::_Scratch_list;
+	// The algorithm used here is largely unchanged from the SGI STL
+	// and is described in The C++ Standard Template Library by Plauger,
+	// Stepanov, Lee, Musser.
+	// Each element of *this is spliced out and merged into one of the
+	// sorted lists in __tmp, then all the lists in __tmp are merged
+	// together and then swapped back into *this.
+	// Because all nodes end up back in *this we do not need to update
+	// this->size() while nodes are temporarily moved out.
+	_Scratch_list __carry;
+	_Scratch_list __tmp[64];
+	_Scratch_list* __fill = __tmp;
+	_Scratch_list* __counter;
+
+	_Scratch_list::_Ptr_cmp<iterator, void> __ptr_comp;
+
+	__try
+	  {
+	    do
+	      {
+		__carry._M_take_one(begin()._M_node);
+
+		for(__counter = __tmp;
+		    __counter != __fill && !__counter->empty();
+		    ++__counter)
+		  {
+
+		    __counter->merge(__carry, __ptr_comp);
+		    __carry.swap(*__counter);
+		  }
+		__carry.swap(*__counter);
+		if (__counter == __fill)
+		  ++__fill;
+	      }
+	    while ( !empty() );
+
+	    for (__counter = __tmp + 1; __counter != __fill; ++__counter)
+	      __counter->merge(__counter[-1], __ptr_comp);
+	    __fill[-1].swap(this->_M_impl._M_node);
+	  }
+	__catch(...)
+	  {
+	    // Move all nodes back into *this.
+	    __carry._M_put_all(end()._M_node);
+	    for (int __i = 0; __i < sizeof(__tmp)/sizeof(__tmp[0]); ++__i)
+	      __tmp[__i]._M_put_all(end()._M_node);
+	    __throw_exception_again;
+	  }
+      }
+    }
+
+  template<typename _Tp, typename _Alloc>
+    template <typename _Predicate>
+      typename list<_Tp, _Alloc>::__remove_return_type
+      list<_Tp, _Alloc>::
+      remove_if(_Predicate __pred)
+      {
+#if !_GLIBCXX_USE_CXX11_ABI
+	size_type __removed __attribute__((__unused__)) = 0;
+#endif
+	list __to_destroy(get_allocator());
+	iterator __first = begin();
+	iterator __last = end();
+	while (__first != __last)
+	  {
+	    iterator __next = __first;
+	    ++__next;
+	    if (__pred(*__first))
+	      {
+		__to_destroy.splice(__to_destroy.begin(), *this, __first);
+#if !_GLIBCXX_USE_CXX11_ABI
+		_GLIBCXX20_ONLY( __removed++ );
+#endif
+	      }
+	    __first = __next;
+	  }
+
+#if !_GLIBCXX_USE_CXX11_ABI
+	return _GLIBCXX20_ONLY( __removed );
+#else
+	return _GLIBCXX20_ONLY( __to_destroy.size() );
+#endif
+      }
+
+  template<typename _Tp, typename _Alloc>
+    template <typename _BinaryPredicate>
+      typename list<_Tp, _Alloc>::__remove_return_type
+      list<_Tp, _Alloc>::
+      unique(_BinaryPredicate __binary_pred)
+      {
+        iterator __first = begin();
+        iterator __last = end();
+        if (__first == __last)
+	  return _GLIBCXX20_ONLY(0);
+#if !_GLIBCXX_USE_CXX11_ABI
+        size_type __removed __attribute__((__unused__)) = 0;
+#endif
+	list __to_destroy(get_allocator());
+        iterator __next = __first;
+        while (++__next != __last)
+	  {
+	    if (__binary_pred(*__first, *__next))
+	      {
+		__to_destroy.splice(__to_destroy.begin(), *this, __next);
+#if !_GLIBCXX_USE_CXX11_ABI
+		_GLIBCXX20_ONLY( __removed++ );
+#endif
+	      }
+	    else
+	      __first = __next;
+	    __next = __first;
+	  }
+
+#if !_GLIBCXX_USE_CXX11_ABI
+	return _GLIBCXX20_ONLY( __removed );
+#else
+	return _GLIBCXX20_ONLY( __to_destroy.size() );
+#endif
+      }
+
+#undef _GLIBCXX20_ONLY
+
+  template<typename _Tp, typename _Alloc>
+    template <typename _StrictWeakOrdering>
+      void
+      list<_Tp, _Alloc>::
+      sort(_StrictWeakOrdering __comp)
+      {
+	// Do nothing if the list has length 0 or 1.
+	if (this->_M_impl._M_node._M_next != &this->_M_impl._M_node
+	    && this->_M_impl._M_node._M_next->_M_next != &this->_M_impl._M_node)
+	{
+	  using __detail::_Scratch_list;
+	  _Scratch_list __carry;
+	  _Scratch_list __tmp[64];
+	  _Scratch_list* __fill = __tmp;
+	  _Scratch_list* __counter;
+
+	_Scratch_list::_Ptr_cmp<iterator, _StrictWeakOrdering> __ptr_comp
+	  = { __comp };
+
+	  __try
+	    {
+	      do
+		{
+		  __carry._M_take_one(begin()._M_node);
+
+		  for(__counter = __tmp;
+		      __counter != __fill && !__counter->empty();
+		      ++__counter)
+		    {
+
+		      __counter->merge(__carry, __ptr_comp);
+		      __carry.swap(*__counter);
+		    }
+		  __carry.swap(*__counter);
+		  if (__counter == __fill)
+		    ++__fill;
+		}
+	      while ( !empty() );
+
+	      for (__counter = __tmp + 1; __counter != __fill; ++__counter)
+		__counter->merge(__counter[-1], __ptr_comp);
+	      __fill[-1].swap(this->_M_impl._M_node);
+	    }
+	  __catch(...)
+	    {
+	      // Move all nodes back into *this.
+	      __carry._M_put_all(end()._M_node);
+	      for (int __i = 0; __i < sizeof(__tmp)/sizeof(__tmp[0]); ++__i)
+		__tmp[__i]._M_put_all(end()._M_node);
+	      __throw_exception_again;
+	    }
+	}
+      }
+
+_GLIBCXX_END_NAMESPACE_CONTAINER
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif /* _LIST_TCC */
+
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@list.tcc.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@list.tcc.blob
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Binary files /dev/null and b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@list.tcc.blob differ
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@locale_classes.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@locale_classes.h
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index 0000000000000000000000000000000000000000..6cad0ff565576fa4191cb43aca2e3e3f63b4985a
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@locale_classes.h
@@ -0,0 +1,859 @@
+// Locale support -*- C++ -*-
+
+// Copyright (C) 1997-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/locale_classes.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{locale}
+ */
+
+//
+// ISO C++ 14882: 22.1  Locales
+//
+
+#ifndef _LOCALE_CLASSES_H
+#define _LOCALE_CLASSES_H 1
+
+#pragma GCC system_header
+
+#include <bits/localefwd.h>
+#include <string>
+#include <ext/atomicity.h>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  // 22.1.1 Class locale
+  /**
+   *  @brief  Container class for localization functionality.
+   *  @ingroup locales
+   *
+   *  The locale class is first a class wrapper for C library locales.  It is
+   *  also an extensible container for user-defined localization.  A locale is
+   *  a collection of facets that implement various localization features such
+   *  as money, time, and number printing.
+   *
+   *  Constructing C++ locales does not change the C library locale.
+   *
+   *  This library supports efficient construction and copying of locales
+   *  through a reference counting implementation of the locale class.
+  */
+  class locale
+  {
+  public:
+    // Types:
+    /// Definition of locale::category.
+    typedef int	category;
+
+    // Forward decls and friends:
+    class facet;
+    class id;
+    class _Impl;
+
+    friend class facet;
+    friend class _Impl;
+
+    template<typename _Facet>
+      friend bool
+      has_facet(const locale&) throw();
+
+    template<typename _Facet>
+      friend const _Facet&
+      use_facet(const locale&);
+
+    template<typename _Cache>
+      friend struct __use_cache;
+
+    ///@{
+    /**
+     *  @brief  Category values.
+     *
+     *  The standard category values are none, ctype, numeric, collate, time,
+     *  monetary, and messages.  They form a bitmask that supports union and
+     *  intersection.  The category all is the union of these values.
+     *
+     *  NB: Order must match _S_facet_categories definition in locale.cc
+    */
+    static const category none		= 0;
+    static const category ctype		= 1L << 0;
+    static const category numeric	= 1L << 1;
+    static const category collate	= 1L << 2;
+    static const category time		= 1L << 3;
+    static const category monetary	= 1L << 4;
+    static const category messages	= 1L << 5;
+    static const category all		= (ctype | numeric | collate |
+					   time  | monetary | messages);
+    ///@}
+
+    // Construct/copy/destroy:
+
+    /**
+     *  @brief  Default constructor.
+     *
+     *  Constructs a copy of the global locale.  If no locale has been
+     *  explicitly set, this is the C locale.
+    */
+    locale() throw();
+
+    /**
+     *  @brief  Copy constructor.
+     *
+     *  Constructs a copy of @a other.
+     *
+     *  @param  __other  The locale to copy.
+    */
+    locale(const locale& __other) throw();
+
+    /**
+     *  @brief  Named locale constructor.
+     *
+     *  Constructs a copy of the named C library locale.
+     *
+     *  @param  __s  Name of the locale to construct.
+     *  @throw  std::runtime_error if __s is null or an undefined locale.
+    */
+    explicit
+    locale(const char* __s);
+
+    /**
+     *  @brief  Construct locale with facets from another locale.
+     *
+     *  Constructs a copy of the locale @a base.  The facets specified by @a
+     *  cat are replaced with those from the locale named by @a s.  If base is
+     *  named, this locale instance will also be named.
+     *
+     *  @param  __base  The locale to copy.
+     *  @param  __s  Name of the locale to use facets from.
+     *  @param  __cat  Set of categories defining the facets to use from __s.
+     *  @throw  std::runtime_error if __s is null or an undefined locale.
+    */
+    locale(const locale& __base, const char* __s, category __cat);
+
+#if __cplusplus >= 201103L
+    /**
+     *  @brief  Named locale constructor.
+     *
+     *  Constructs a copy of the named C library locale.
+     *
+     *  @param  __s  Name of the locale to construct.
+     *  @throw  std::runtime_error if __s is an undefined locale.
+    */
+    explicit
+    locale(const std::string& __s) : locale(__s.c_str()) { }
+
+    /**
+     *  @brief  Construct locale with facets from another locale.
+     *
+     *  Constructs a copy of the locale @a base.  The facets specified by @a
+     *  cat are replaced with those from the locale named by @a s.  If base is
+     *  named, this locale instance will also be named.
+     *
+     *  @param  __base  The locale to copy.
+     *  @param  __s  Name of the locale to use facets from.
+     *  @param  __cat  Set of categories defining the facets to use from __s.
+     *  @throw  std::runtime_error if __s is an undefined locale.
+    */
+    locale(const locale& __base, const std::string& __s, category __cat)
+    : locale(__base, __s.c_str(), __cat) { }
+#endif
+
+    /**
+     *  @brief  Construct locale with facets from another locale.
+     *
+     *  Constructs a copy of the locale @a base.  The facets specified by @a
+     *  cat are replaced with those from the locale @a add.  If @a base and @a
+     *  add are named, this locale instance will also be named.
+     *
+     *  @param  __base  The locale to copy.
+     *  @param  __add  The locale to use facets from.
+     *  @param  __cat  Set of categories defining the facets to use from add.
+    */
+    locale(const locale& __base, const locale& __add, category __cat);
+
+    /**
+     *  @brief  Construct locale with another facet.
+     *
+     *  Constructs a copy of the locale @a __other.  The facet @a __f
+     *  is added to @a __other, replacing an existing facet of type
+     *  Facet if there is one.  If @a __f is null, this locale is a
+     *  copy of @a __other.
+     *
+     *  @param  __other  The locale to copy.
+     *  @param  __f  The facet to add in.
+    */
+    template<typename _Facet>
+      locale(const locale& __other, _Facet* __f);
+
+    /// Locale destructor.
+    ~locale() throw();
+
+    /**
+     *  @brief  Assignment operator.
+     *
+     *  Set this locale to be a copy of @a other.
+     *
+     *  @param  __other  The locale to copy.
+     *  @return  A reference to this locale.
+    */
+    const locale&
+    operator=(const locale& __other) throw();
+
+    /**
+     *  @brief  Construct locale with another facet.
+     *
+     *  Constructs and returns a new copy of this locale.  Adds or replaces an
+     *  existing facet of type Facet from the locale @a other into the new
+     *  locale.
+     *
+     *  @tparam  _Facet  The facet type to copy from other
+     *  @param  __other  The locale to copy from.
+     *  @return  Newly constructed locale.
+     *  @throw  std::runtime_error if __other has no facet of type _Facet.
+    */
+    template<typename _Facet>
+      locale
+      combine(const locale& __other) const;
+
+    // Locale operations:
+    /**
+     *  @brief  Return locale name.
+     *  @return  Locale name or "*" if unnamed.
+    */
+    _GLIBCXX_DEFAULT_ABI_TAG
+    string
+    name() const;
+
+    /**
+     *  @brief  Locale equality.
+     *
+     *  @param  __other  The locale to compare against.
+     *  @return  True if other and this refer to the same locale instance, are
+     *		 copies, or have the same name.  False otherwise.
+    */
+    bool
+    operator==(const locale& __other) const throw();
+
+#if __cpp_impl_three_way_comparison < 201907L
+    /**
+     *  @brief  Locale inequality.
+     *
+     *  @param  __other  The locale to compare against.
+     *  @return  ! (*this == __other)
+    */
+    bool
+    operator!=(const locale& __other) const throw()
+    { return !(this->operator==(__other)); }
+#endif
+
+    /**
+     *  @brief  Compare two strings according to collate.
+     *
+     *  Template operator to compare two strings using the compare function of
+     *  the collate facet in this locale.  One use is to provide the locale to
+     *  the sort function.  For example, a vector v of strings could be sorted
+     *  according to locale loc by doing:
+     *  @code
+     *  std::sort(v.begin(), v.end(), loc);
+     *  @endcode
+     *
+     *  @param  __s1  First string to compare.
+     *  @param  __s2  Second string to compare.
+     *  @return  True if collate<_Char> facet compares __s1 < __s2, else false.
+    */
+    template<typename _Char, typename _Traits, typename _Alloc>
+      bool
+      operator()(const basic_string<_Char, _Traits, _Alloc>& __s1,
+		 const basic_string<_Char, _Traits, _Alloc>& __s2) const;
+
+    // Global locale objects:
+    /**
+     *  @brief  Set global locale
+     *
+     *  This function sets the global locale to the argument and returns a
+     *  copy of the previous global locale.  If the argument has a name, it
+     *  will also call std::setlocale(LC_ALL, loc.name()).
+     *
+     *  @param  __loc  The new locale to make global.
+     *  @return  Copy of the old global locale.
+    */
+    static locale
+    global(const locale& __loc);
+
+    /**
+     *  @brief  Return reference to the C locale.
+    */
+    static const locale&
+    classic();
+
+  private:
+    // The (shared) implementation
+    _Impl*		_M_impl;
+
+    // The "C" reference locale
+    static _Impl*       _S_classic;
+
+    // Current global locale
+    static _Impl*	_S_global;
+
+    // Names of underlying locale categories.
+    // NB: locale::global() has to know how to modify all the
+    // underlying categories, not just the ones required by the C++
+    // standard.
+    static const char* const* const _S_categories;
+
+    // Number of standard categories. For C++, these categories are
+    // collate, ctype, monetary, numeric, time, and messages. These
+    // directly correspond to ISO C99 macros LC_COLLATE, LC_CTYPE,
+    // LC_MONETARY, LC_NUMERIC, and LC_TIME. In addition, POSIX (IEEE
+    // 1003.1-2001) specifies LC_MESSAGES.
+    // In addition to the standard categories, the underlying
+    // operating system is allowed to define extra LC_*
+    // macros. For GNU systems, the following are also valid:
+    // LC_PAPER, LC_NAME, LC_ADDRESS, LC_TELEPHONE, LC_MEASUREMENT,
+    // and LC_IDENTIFICATION.
+    enum { _S_categories_size = 6 + _GLIBCXX_NUM_CATEGORIES };
+
+#ifdef __GTHREADS
+    static __gthread_once_t _S_once;
+#endif
+
+    explicit
+    locale(_Impl*) throw();
+
+    static void
+    _S_initialize();
+
+    static void
+    _S_initialize_once() throw();
+
+    static category
+    _S_normalize_category(category);
+
+    void
+    _M_coalesce(const locale& __base, const locale& __add, category __cat);
+
+#if _GLIBCXX_USE_CXX11_ABI
+    static const id* const _S_twinned_facets[];
+#endif
+  };
+
+
+  // 22.1.1.1.2  Class locale::facet
+  /**
+   *  @brief  Localization functionality base class.
+   *  @ingroup locales
+   *
+   *  The facet class is the base class for a localization feature, such as
+   *  money, time, and number printing.  It provides common support for facets
+   *  and reference management.
+   *
+   *  Facets may not be copied or assigned.
+  */
+  class locale::facet
+  {
+  private:
+    friend class locale;
+    friend class locale::_Impl;
+
+    mutable _Atomic_word		_M_refcount;
+
+    // Contains data from the underlying "C" library for the classic locale.
+    static __c_locale                   _S_c_locale;
+
+    // String literal for the name of the classic locale.
+    static const char			_S_c_name[2];
+
+#ifdef __GTHREADS
+    static __gthread_once_t		_S_once;
+#endif
+
+    static void
+    _S_initialize_once();
+
+  protected:
+    /**
+     *  @brief  Facet constructor.
+     *
+     *  This is the constructor provided by the standard.  If refs is 0, the
+     *  facet is destroyed when the last referencing locale is destroyed.
+     *  Otherwise the facet will never be destroyed.
+     *
+     *  @param __refs  The initial value for reference count.
+    */
+    explicit
+    facet(size_t __refs = 0) throw() : _M_refcount(__refs ? 1 : 0)
+    { }
+
+    /// Facet destructor.
+    virtual
+    ~facet();
+
+    static void
+    _S_create_c_locale(__c_locale& __cloc, const char* __s,
+		       __c_locale __old = 0);
+
+    static __c_locale
+    _S_clone_c_locale(__c_locale& __cloc) throw();
+
+    static void
+    _S_destroy_c_locale(__c_locale& __cloc);
+
+    static __c_locale
+    _S_lc_ctype_c_locale(__c_locale __cloc, const char* __s);
+
+    // Returns data from the underlying "C" library data for the
+    // classic locale.
+    static __c_locale
+    _S_get_c_locale();
+
+    _GLIBCXX_CONST static const char*
+    _S_get_c_name() throw();
+
+#if __cplusplus < 201103L
+  private:
+    facet(const facet&);  // Not defined.
+
+    facet&
+    operator=(const facet&);  // Not defined.
+#else
+    facet(const facet&) = delete;
+
+    facet&
+    operator=(const facet&) = delete;
+#endif
+
+  private:
+    void
+    _M_add_reference() const throw()
+    { __gnu_cxx::__atomic_add_dispatch(&_M_refcount, 1); }
+
+    void
+    _M_remove_reference() const throw()
+    {
+      // Be race-detector-friendly.  For more info see bits/c++config.
+      _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&_M_refcount);
+      if (__gnu_cxx::__exchange_and_add_dispatch(&_M_refcount, -1) == 1)
+	{
+          _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&_M_refcount);
+	  __try
+	    { delete this; }
+	  __catch(...)
+	    { }
+	}
+    }
+
+    const facet* _M_sso_shim(const id*) const;
+    const facet* _M_cow_shim(const id*) const;
+
+  protected:
+    class __shim; // For internal use only.
+  };
+
+
+  // 22.1.1.1.3 Class locale::id
+  /**
+   *  @brief  Facet ID class.
+   *  @ingroup locales
+   *
+   *  The ID class provides facets with an index used to identify them.
+   *  Every facet class must define a public static member locale::id, or be
+   *  derived from a facet that provides this member, otherwise the facet
+   *  cannot be used in a locale.  The locale::id ensures that each class
+   *  type gets a unique identifier.
+  */
+  class locale::id
+  {
+  private:
+    friend class locale;
+    friend class locale::_Impl;
+
+    template<typename _Facet>
+      friend const _Facet&
+      use_facet(const locale&);
+
+    template<typename _Facet>
+      friend bool
+      has_facet(const locale&) throw();
+
+    // NB: There is no accessor for _M_index because it may be used
+    // before the constructor is run; the effect of calling a member
+    // function (even an inline) would be undefined.
+    mutable size_t		_M_index;
+
+    // Last id number assigned.
+    static _Atomic_word		_S_refcount;
+
+    void
+    operator=(const id&);  // Not defined.
+
+    id(const id&);  // Not defined.
+
+  public:
+    // NB: This class is always a static data member, and thus can be
+    // counted on to be zero-initialized.
+    /// Constructor.
+    id() { }
+
+    size_t
+    _M_id() const throw();
+  };
+
+
+  // Implementation object for locale.
+  class locale::_Impl
+  {
+  public:
+    // Friends.
+    friend class locale;
+    friend class locale::facet;
+
+    template<typename _Facet>
+      friend bool
+      has_facet(const locale&) throw();
+
+    template<typename _Facet>
+      friend const _Facet&
+      use_facet(const locale&);
+
+    template<typename _Cache>
+      friend struct __use_cache;
+
+  private:
+    // Data Members.
+    _Atomic_word			_M_refcount;
+    const facet**			_M_facets;
+    size_t				_M_facets_size;
+    const facet**			_M_caches;
+    char**				_M_names;
+    static const locale::id* const	_S_id_ctype[];
+    static const locale::id* const	_S_id_numeric[];
+    static const locale::id* const	_S_id_collate[];
+    static const locale::id* const	_S_id_time[];
+    static const locale::id* const	_S_id_monetary[];
+    static const locale::id* const	_S_id_messages[];
+    static const locale::id* const* const _S_facet_categories[];
+
+    void
+    _M_add_reference() throw()
+    { __gnu_cxx::__atomic_add_dispatch(&_M_refcount, 1); }
+
+    void
+    _M_remove_reference() throw()
+    {
+      // Be race-detector-friendly.  For more info see bits/c++config.
+      _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&_M_refcount);
+      if (__gnu_cxx::__exchange_and_add_dispatch(&_M_refcount, -1) == 1)
+	{
+          _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&_M_refcount);
+	  __try
+	    { delete this; }
+	  __catch(...)
+	    { }
+	}
+    }
+
+    _Impl(const _Impl&, size_t);
+    _Impl(const char*, size_t);
+    _Impl(size_t) throw();
+
+   ~_Impl() throw();
+
+    _Impl(const _Impl&);  // Not defined.
+
+    void
+    operator=(const _Impl&);  // Not defined.
+
+    bool
+    _M_check_same_name()
+    {
+      bool __ret = true;
+      if (_M_names[1])
+	// We must actually compare all the _M_names: can be all equal!
+	for (size_t __i = 0; __ret && __i < _S_categories_size - 1; ++__i)
+	  __ret = __builtin_strcmp(_M_names[__i], _M_names[__i + 1]) == 0;
+      return __ret;
+    }
+
+    void
+    _M_replace_categories(const _Impl*, category);
+
+    void
+    _M_replace_category(const _Impl*, const locale::id* const*);
+
+    void
+    _M_replace_facet(const _Impl*, const locale::id*);
+
+    void
+    _M_install_facet(const locale::id*, const facet*);
+
+    template<typename _Facet>
+      void
+      _M_init_facet(_Facet* __facet)
+      { _M_install_facet(&_Facet::id, __facet); }
+
+    template<typename _Facet>
+      void
+      _M_init_facet_unchecked(_Facet* __facet)
+      {
+	__facet->_M_add_reference();
+	_M_facets[_Facet::id._M_id()] = __facet;
+      }
+
+    void
+    _M_install_cache(const facet*, size_t);
+
+    void _M_init_extra(facet**);
+    void _M_init_extra(void*, void*, const char*, const char*);
+
+#ifdef _GLIBCXX_LONG_DOUBLE_ALT128_COMPAT
+    void _M_init_extra_ldbl128(bool);
+#endif
+  };
+
+
+  /**
+   *  @brief  Facet for localized string comparison.
+   *
+   *  This facet encapsulates the code to compare strings in a localized
+   *  manner.
+   *
+   *  The collate template uses protected virtual functions to provide
+   *  the actual results.  The public accessors forward the call to
+   *  the virtual functions.  These virtual functions are hooks for
+   *  developers to implement the behavior they require from the
+   *  collate facet.
+  */
+  template<typename _CharT>
+    class _GLIBCXX_NAMESPACE_CXX11 collate : public locale::facet
+    {
+    public:
+      // Types:
+      ///@{
+      /// Public typedefs
+      typedef _CharT			char_type;
+      typedef basic_string<_CharT>	string_type;
+      ///@}
+
+    protected:
+      // Underlying "C" library locale information saved from
+      // initialization, needed by collate_byname as well.
+      __c_locale			_M_c_locale_collate;
+
+    public:
+      /// Numpunct facet id.
+      static locale::id			id;
+
+      /**
+       *  @brief  Constructor performs initialization.
+       *
+       *  This is the constructor provided by the standard.
+       *
+       *  @param __refs  Passed to the base facet class.
+      */
+      explicit
+      collate(size_t __refs = 0)
+      : facet(__refs), _M_c_locale_collate(_S_get_c_locale())
+      { }
+
+      /**
+       *  @brief  Internal constructor. Not for general use.
+       *
+       *  This is a constructor for use by the library itself to set up new
+       *  locales.
+       *
+       *  @param __cloc  The C locale.
+       *  @param __refs  Passed to the base facet class.
+      */
+      explicit
+      collate(__c_locale __cloc, size_t __refs = 0)
+      : facet(__refs), _M_c_locale_collate(_S_clone_c_locale(__cloc))
+      { }
+
+      /**
+       *  @brief  Compare two strings.
+       *
+       *  This function compares two strings and returns the result by calling
+       *  collate::do_compare().
+       *
+       *  @param __lo1  Start of string 1.
+       *  @param __hi1  End of string 1.
+       *  @param __lo2  Start of string 2.
+       *  @param __hi2  End of string 2.
+       *  @return  1 if string1 > string2, -1 if string1 < string2, else 0.
+      */
+      int
+      compare(const _CharT* __lo1, const _CharT* __hi1,
+	      const _CharT* __lo2, const _CharT* __hi2) const
+      { return this->do_compare(__lo1, __hi1, __lo2, __hi2); }
+
+      /**
+       *  @brief  Transform string to comparable form.
+       *
+       *  This function is a wrapper for strxfrm functionality.  It takes the
+       *  input string and returns a modified string that can be directly
+       *  compared to other transformed strings.  In the C locale, this
+       *  function just returns a copy of the input string.  In some other
+       *  locales, it may replace two chars with one, change a char for
+       *  another, etc.  It does so by returning collate::do_transform().
+       *
+       *  @param __lo  Start of string.
+       *  @param __hi  End of string.
+       *  @return  Transformed string_type.
+      */
+      string_type
+      transform(const _CharT* __lo, const _CharT* __hi) const
+      { return this->do_transform(__lo, __hi); }
+
+      /**
+       *  @brief  Return hash of a string.
+       *
+       *  This function computes and returns a hash on the input string.  It
+       *  does so by returning collate::do_hash().
+       *
+       *  @param __lo  Start of string.
+       *  @param __hi  End of string.
+       *  @return  Hash value.
+      */
+      long
+      hash(const _CharT* __lo, const _CharT* __hi) const
+      { return this->do_hash(__lo, __hi); }
+
+      // Used to abstract out _CharT bits in virtual member functions, below.
+      int
+      _M_compare(const _CharT*, const _CharT*) const throw();
+
+      size_t
+      _M_transform(_CharT*, const _CharT*, size_t) const throw();
+
+  protected:
+      /// Destructor.
+      virtual
+      ~collate()
+      { _S_destroy_c_locale(_M_c_locale_collate); }
+
+      /**
+       *  @brief  Compare two strings.
+       *
+       *  This function is a hook for derived classes to change the value
+       *  returned.  @see compare().
+       *
+       *  @param __lo1  Start of string 1.
+       *  @param __hi1  End of string 1.
+       *  @param __lo2  Start of string 2.
+       *  @param __hi2  End of string 2.
+       *  @return  1 if string1 > string2, -1 if string1 < string2, else 0.
+      */
+      virtual int
+      do_compare(const _CharT* __lo1, const _CharT* __hi1,
+		 const _CharT* __lo2, const _CharT* __hi2) const;
+
+      /**
+       *  @brief  Transform string to comparable form.
+       *
+       *  This function is a hook for derived classes to change the value
+       *  returned.
+       *
+       *  @param __lo  Start.
+       *  @param __hi  End.
+       *  @return  transformed string.
+      */
+      virtual string_type
+      do_transform(const _CharT* __lo, const _CharT* __hi) const;
+
+      /**
+       *  @brief  Return hash of a string.
+       *
+       *  This function computes and returns a hash on the input string.  This
+       *  function is a hook for derived classes to change the value returned.
+       *
+       *  @param __lo  Start of string.
+       *  @param __hi  End of string.
+       *  @return  Hash value.
+      */
+      virtual long
+      do_hash(const _CharT* __lo, const _CharT* __hi) const;
+    };
+
+  template<typename _CharT>
+    locale::id collate<_CharT>::id;
+
+  // Specializations.
+  template<>
+    int
+    collate<char>::_M_compare(const char*, const char*) const throw();
+
+  template<>
+    size_t
+    collate<char>::_M_transform(char*, const char*, size_t) const throw();
+
+#ifdef _GLIBCXX_USE_WCHAR_T
+  template<>
+    int
+    collate<wchar_t>::_M_compare(const wchar_t*, const wchar_t*) const throw();
+
+  template<>
+    size_t
+    collate<wchar_t>::_M_transform(wchar_t*, const wchar_t*, size_t) const throw();
+#endif
+
+  /// class collate_byname [22.2.4.2].
+  template<typename _CharT>
+    class _GLIBCXX_NAMESPACE_CXX11 collate_byname : public collate<_CharT>
+    {
+    public:
+      ///@{
+      /// Public typedefs
+      typedef _CharT               char_type;
+      typedef basic_string<_CharT> string_type;
+      ///@}
+
+      explicit
+      collate_byname(const char* __s, size_t __refs = 0)
+      : collate<_CharT>(__refs)
+      {
+	if (__builtin_strcmp(__s, "C") != 0
+	    && __builtin_strcmp(__s, "POSIX") != 0)
+	  {
+	    this->_S_destroy_c_locale(this->_M_c_locale_collate);
+	    this->_S_create_c_locale(this->_M_c_locale_collate, __s);
+	  }
+      }
+
+#if __cplusplus >= 201103L
+      explicit
+      collate_byname(const string& __s, size_t __refs = 0)
+      : collate_byname(__s.c_str(), __refs) { }
+#endif
+
+    protected:
+      virtual
+      ~collate_byname() { }
+    };
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+# include <bits/locale_classes.tcc>
+
+#endif
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+// Locale support -*- C++ -*-
+
+// Copyright (C) 2007-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/locale_classes.tcc
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{locale}
+ */
+
+//
+// ISO C++ 14882: 22.1  Locales
+//
+
+#ifndef _LOCALE_CLASSES_TCC
+#define _LOCALE_CLASSES_TCC 1
+
+#pragma GCC system_header
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  template<typename _Facet>
+    locale::
+    locale(const locale& __other, _Facet* __f)
+    {
+      _M_impl = new _Impl(*__other._M_impl, 1);
+
+      __try
+	{ _M_impl->_M_install_facet(&_Facet::id, __f); }
+      __catch(...)
+	{
+	  _M_impl->_M_remove_reference();
+	  __throw_exception_again;
+	}
+      delete [] _M_impl->_M_names[0];
+      _M_impl->_M_names[0] = 0;   // Unnamed.
+    }
+
+  template<typename _Facet>
+    locale
+    locale::
+    combine(const locale& __other) const
+    {
+      _Impl* __tmp = new _Impl(*_M_impl, 1);
+      __try
+	{
+	  __tmp->_M_replace_facet(__other._M_impl, &_Facet::id);
+	}
+      __catch(...)
+	{
+	  __tmp->_M_remove_reference();
+	  __throw_exception_again;
+	}
+      return locale(__tmp);
+    }
+
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    bool
+    locale::
+    operator()(const basic_string<_CharT, _Traits, _Alloc>& __s1,
+	       const basic_string<_CharT, _Traits, _Alloc>& __s2) const
+    {
+      typedef std::collate<_CharT> __collate_type;
+      const __collate_type& __collate = use_facet<__collate_type>(*this);
+      return (__collate.compare(__s1.data(), __s1.data() + __s1.length(),
+				__s2.data(), __s2.data() + __s2.length()) < 0);
+    }
+
+  /**
+   *  @brief  Test for the presence of a facet.
+   *  @ingroup locales
+   *
+   *  has_facet tests the locale argument for the presence of the facet type
+   *  provided as the template parameter.  Facets derived from the facet
+   *  parameter will also return true.
+   *
+   *  @tparam  _Facet  The facet type to test the presence of.
+   *  @param  __loc  The locale to test.
+   *  @return  true if @p __loc contains a facet of type _Facet, else false.
+  */
+  template<typename _Facet>
+    bool
+    has_facet(const locale& __loc) throw()
+    {
+      const size_t __i = _Facet::id._M_id();
+      const locale::facet** __facets = __loc._M_impl->_M_facets;
+      return (__i < __loc._M_impl->_M_facets_size
+#if __cpp_rtti
+	      && dynamic_cast<const _Facet*>(__facets[__i]));
+#else
+              && static_cast<const _Facet*>(__facets[__i]));
+#endif
+    }
+
+  /**
+   *  @brief  Return a facet.
+   *  @ingroup locales
+   *
+   *  use_facet looks for and returns a reference to a facet of type Facet
+   *  where Facet is the template parameter.  If has_facet(locale) is true,
+   *  there is a suitable facet to return.  It throws std::bad_cast if the
+   *  locale doesn't contain a facet of type Facet.
+   *
+   *  @tparam  _Facet  The facet type to access.
+   *  @param  __loc  The locale to use.
+   *  @return  Reference to facet of type Facet.
+   *  @throw  std::bad_cast if @p __loc doesn't contain a facet of type _Facet.
+  */
+  template<typename _Facet>
+    const _Facet&
+    use_facet(const locale& __loc)
+    {
+      const size_t __i = _Facet::id._M_id();
+      const locale::facet** __facets = __loc._M_impl->_M_facets;
+      if (__i >= __loc._M_impl->_M_facets_size || !__facets[__i])
+        __throw_bad_cast();
+#if __cpp_rtti
+      return dynamic_cast<const _Facet&>(*__facets[__i]);
+#else
+      return static_cast<const _Facet&>(*__facets[__i]);
+#endif
+    }
+
+
+  // Generic version does nothing.
+  template<typename _CharT>
+    int
+    collate<_CharT>::_M_compare(const _CharT*, const _CharT*) const throw ()
+    { return 0; }
+
+  // Generic version does nothing.
+  template<typename _CharT>
+    size_t
+    collate<_CharT>::_M_transform(_CharT*, const _CharT*, size_t) const throw ()
+    { return 0; }
+
+  template<typename _CharT>
+    int
+    collate<_CharT>::
+    do_compare(const _CharT* __lo1, const _CharT* __hi1,
+	       const _CharT* __lo2, const _CharT* __hi2) const
+    {
+      // strcoll assumes zero-terminated strings so we make a copy
+      // and then put a zero at the end.
+      const string_type __one(__lo1, __hi1);
+      const string_type __two(__lo2, __hi2);
+
+      const _CharT* __p = __one.c_str();
+      const _CharT* __pend = __one.data() + __one.length();
+      const _CharT* __q = __two.c_str();
+      const _CharT* __qend = __two.data() + __two.length();
+
+      // strcoll stops when it sees a nul character so we break
+      // the strings into zero-terminated substrings and pass those
+      // to strcoll.
+      for (;;)
+	{
+	  const int __res = _M_compare(__p, __q);
+	  if (__res)
+	    return __res;
+
+	  __p += char_traits<_CharT>::length(__p);
+	  __q += char_traits<_CharT>::length(__q);
+	  if (__p == __pend && __q == __qend)
+	    return 0;
+	  else if (__p == __pend)
+	    return -1;
+	  else if (__q == __qend)
+	    return 1;
+
+	  __p++;
+	  __q++;
+	}
+    }
+
+  template<typename _CharT>
+    typename collate<_CharT>::string_type
+    collate<_CharT>::
+    do_transform(const _CharT* __lo, const _CharT* __hi) const
+    {
+      string_type __ret;
+
+      // strxfrm assumes zero-terminated strings so we make a copy
+      const string_type __str(__lo, __hi);
+
+      const _CharT* __p = __str.c_str();
+      const _CharT* __pend = __str.data() + __str.length();
+
+      size_t __len = (__hi - __lo) * 2;
+
+      _CharT* __c = new _CharT[__len];
+
+      __try
+	{
+	  // strxfrm stops when it sees a nul character so we break
+	  // the string into zero-terminated substrings and pass those
+	  // to strxfrm.
+	  for (;;)
+	    {
+	      // First try a buffer perhaps big enough.
+	      size_t __res = _M_transform(__c, __p, __len);
+	      // If the buffer was not large enough, try again with the
+	      // correct size.
+	      if (__res >= __len)
+		{
+		  __len = __res + 1;
+		  delete [] __c, __c = 0;
+		  __c = new _CharT[__len];
+		  __res = _M_transform(__c, __p, __len);
+		}
+
+	      __ret.append(__c, __res);
+	      __p += char_traits<_CharT>::length(__p);
+	      if (__p == __pend)
+		break;
+
+	      __p++;
+	      __ret.push_back(_CharT());
+	    }
+	}
+      __catch(...)
+	{
+	  delete [] __c;
+	  __throw_exception_again;
+	}
+
+      delete [] __c;
+
+      return __ret;
+    }
+
+  template<typename _CharT>
+    long
+    collate<_CharT>::
+    do_hash(const _CharT* __lo, const _CharT* __hi) const
+    {
+      unsigned long __val = 0;
+      for (; __lo < __hi; ++__lo)
+	__val =
+	  *__lo + ((__val << 7)
+		   | (__val >> (__gnu_cxx::__numeric_traits<unsigned long>::
+				__digits - 7)));
+      return static_cast<long>(__val);
+    }
+
+  // Inhibit implicit instantiations for required instantiations,
+  // which are defined via explicit instantiations elsewhere.
+#if _GLIBCXX_EXTERN_TEMPLATE
+  extern template class collate<char>;
+  extern template class collate_byname<char>;
+
+  extern template
+    const collate<char>&
+    use_facet<collate<char> >(const locale&);
+
+  extern template
+    bool
+    has_facet<collate<char> >(const locale&);
+
+#ifdef _GLIBCXX_USE_WCHAR_T
+  extern template class collate<wchar_t>;
+  extern template class collate_byname<wchar_t>;
+
+  extern template
+    const collate<wchar_t>&
+    use_facet<collate<wchar_t> >(const locale&);
+
+  extern template
+    bool
+    has_facet<collate<wchar_t> >(const locale&);
+#endif
+#endif
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@locale_conv.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@locale_conv.h
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@locale_conv.h
@@ -0,0 +1,634 @@
+// wstring_convert implementation -*- C++ -*-
+
+// Copyright (C) 2015-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/locale_conv.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{locale}
+ */
+
+#ifndef _LOCALE_CONV_H
+#define _LOCALE_CONV_H 1
+
+#if __cplusplus < 201103L
+# include <bits/c++0x_warning.h>
+#else
+
+#include <streambuf>
+#include <bits/stringfwd.h>
+#include <bits/allocator.h>
+#include <bits/codecvt.h>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /**
+   * @addtogroup locales
+   * @{
+   */
+
+  template<typename _OutStr, typename _InChar, typename _Codecvt,
+	   typename _State, typename _Fn>
+    bool
+    __do_str_codecvt(const _InChar* __first, const _InChar* __last,
+		     _OutStr& __outstr, const _Codecvt& __cvt, _State& __state,
+		     size_t& __count, _Fn __fn)
+    {
+      if (__first == __last)
+	{
+	  __outstr.clear();
+	  __count = 0;
+	  return true;
+	}
+
+      size_t __outchars = 0;
+      auto __next = __first;
+      const auto __maxlen = __cvt.max_length() + 1;
+
+      codecvt_base::result __result;
+      do
+	{
+	  __outstr.resize(__outstr.size() + (__last - __next) * __maxlen);
+	  auto __outnext = &__outstr.front() + __outchars;
+	  auto const __outlast = &__outstr.back() + 1;
+	  __result = (__cvt.*__fn)(__state, __next, __last, __next,
+					__outnext, __outlast, __outnext);
+	  __outchars = __outnext - &__outstr.front();
+	}
+      while (__result == codecvt_base::partial && __next != __last
+	     && ptrdiff_t(__outstr.size() - __outchars) < __maxlen);
+
+      if (__result == codecvt_base::error)
+	{
+	  __count = __next - __first;
+	  return false;
+	}
+
+      // The codecvt facet will only return noconv when the types are
+      // the same, so avoid instantiating basic_string::assign otherwise
+      if _GLIBCXX17_CONSTEXPR (is_same<typename _Codecvt::intern_type,
+				       typename _Codecvt::extern_type>())
+	if (__result == codecvt_base::noconv)
+	  {
+	    __outstr.assign(__first, __last);
+	    __count = __last - __first;
+	    return true;
+	  }
+
+      __outstr.resize(__outchars);
+      __count = __next - __first;
+      return true;
+    }
+
+  // Convert narrow character string to wide.
+  template<typename _CharT, typename _Traits, typename _Alloc, typename _State>
+    inline bool
+    __str_codecvt_in(const char* __first, const char* __last,
+		     basic_string<_CharT, _Traits, _Alloc>& __outstr,
+		     const codecvt<_CharT, char, _State>& __cvt,
+		     _State& __state, size_t& __count)
+    {
+      using _Codecvt = codecvt<_CharT, char, _State>;
+      using _ConvFn
+	= codecvt_base::result
+	  (_Codecvt::*)(_State&, const char*, const char*, const char*&,
+			_CharT*, _CharT*, _CharT*&) const;
+      _ConvFn __fn = &codecvt<_CharT, char, _State>::in;
+      return __do_str_codecvt(__first, __last, __outstr, __cvt, __state,
+			      __count, __fn);
+    }
+
+  // As above, but with no __count parameter
+  template<typename _CharT, typename _Traits, typename _Alloc, typename _State>
+    inline bool
+    __str_codecvt_in(const char* __first, const char* __last,
+		     basic_string<_CharT, _Traits, _Alloc>& __outstr,
+		     const codecvt<_CharT, char, _State>& __cvt)
+    {
+      _State __state = {};
+      size_t __n;
+      return __str_codecvt_in(__first, __last, __outstr, __cvt, __state, __n);
+    }
+
+  // As above, but returns false for partial conversion
+  template<typename _CharT, typename _Traits, typename _Alloc, typename _State>
+    inline bool
+    __str_codecvt_in_all(const char* __first, const char* __last,
+			 basic_string<_CharT, _Traits, _Alloc>& __outstr,
+			 const codecvt<_CharT, char, _State>& __cvt)
+    {
+      _State __state = {};
+      size_t __n;
+      return __str_codecvt_in(__first, __last, __outstr, __cvt, __state, __n)
+	&& (__n == size_t(__last - __first));
+    }
+
+  // Convert wide character string to narrow.
+  template<typename _CharT, typename _Traits, typename _Alloc, typename _State>
+    inline bool
+    __str_codecvt_out(const _CharT* __first, const _CharT* __last,
+		      basic_string<char, _Traits, _Alloc>& __outstr,
+		      const codecvt<_CharT, char, _State>& __cvt,
+		      _State& __state, size_t& __count)
+    {
+      using _Codecvt = codecvt<_CharT, char, _State>;
+      using _ConvFn
+	= codecvt_base::result
+	  (_Codecvt::*)(_State&, const _CharT*, const _CharT*, const _CharT*&,
+			char*, char*, char*&) const;
+      _ConvFn __fn = &codecvt<_CharT, char, _State>::out;
+      return __do_str_codecvt(__first, __last, __outstr, __cvt, __state,
+			      __count, __fn);
+    }
+
+  // As above, but with no __count parameter
+  template<typename _CharT, typename _Traits, typename _Alloc, typename _State>
+    inline bool
+    __str_codecvt_out(const _CharT* __first, const _CharT* __last,
+		      basic_string<char, _Traits, _Alloc>& __outstr,
+		      const codecvt<_CharT, char, _State>& __cvt)
+    {
+      _State __state = {};
+      size_t __n;
+      return __str_codecvt_out(__first, __last, __outstr, __cvt, __state, __n);
+    }
+
+  // As above, but returns false for partial conversions
+  template<typename _CharT, typename _Traits, typename _Alloc, typename _State>
+    inline bool
+    __str_codecvt_out_all(const _CharT* __first, const _CharT* __last,
+			  basic_string<char, _Traits, _Alloc>& __outstr,
+			  const codecvt<_CharT, char, _State>& __cvt)
+    {
+      _State __state = {};
+      size_t __n;
+      return __str_codecvt_out(__first, __last, __outstr, __cvt, __state, __n)
+	&& (__n == size_t(__last - __first));
+    }
+
+#ifdef _GLIBCXX_USE_CHAR8_T
+
+  // Convert wide character string to narrow.
+  template<typename _CharT, typename _Traits, typename _Alloc, typename _State>
+    inline bool
+    __str_codecvt_out(const _CharT* __first, const _CharT* __last,
+		      basic_string<char8_t, _Traits, _Alloc>& __outstr,
+		      const codecvt<_CharT, char8_t, _State>& __cvt,
+		      _State& __state, size_t& __count)
+    {
+      using _Codecvt = codecvt<_CharT, char8_t, _State>;
+      using _ConvFn
+	= codecvt_base::result
+	  (_Codecvt::*)(_State&, const _CharT*, const _CharT*, const _CharT*&,
+			char8_t*, char8_t*, char8_t*&) const;
+      _ConvFn __fn = &codecvt<_CharT, char8_t, _State>::out;
+      return __do_str_codecvt(__first, __last, __outstr, __cvt, __state,
+			      __count, __fn);
+    }
+
+  template<typename _CharT, typename _Traits, typename _Alloc, typename _State>
+    inline bool
+    __str_codecvt_out(const _CharT* __first, const _CharT* __last,
+		      basic_string<char8_t, _Traits, _Alloc>& __outstr,
+		      const codecvt<_CharT, char8_t, _State>& __cvt)
+    {
+      _State __state = {};
+      size_t __n;
+      return __str_codecvt_out(__first, __last, __outstr, __cvt, __state, __n);
+    }
+
+#endif  // _GLIBCXX_USE_CHAR8_T
+
+  namespace __detail
+  {
+    template<typename _Tp>
+      struct _Scoped_ptr
+      {
+	__attribute__((__nonnull__(2)))
+	explicit
+	_Scoped_ptr(_Tp* __ptr) noexcept
+	: _M_ptr(__ptr)
+	{ }
+
+	_Scoped_ptr(_Tp* __ptr, const char* __msg)
+	: _M_ptr(__ptr)
+	{
+	  if (!__ptr)
+	    __throw_logic_error(__msg);
+	}
+
+	~_Scoped_ptr() { delete _M_ptr; }
+
+	_Scoped_ptr(const _Scoped_ptr&) = delete;
+	_Scoped_ptr& operator=(const _Scoped_ptr&) = delete;
+
+	__attribute__((__returns_nonnull__))
+	_Tp* operator->() const noexcept { return _M_ptr; }
+
+	_Tp& operator*() const noexcept { return *_M_ptr; }
+
+      private:
+	_Tp* _M_ptr;
+      };
+  }
+
+_GLIBCXX_BEGIN_NAMESPACE_CXX11
+
+  /// String conversions
+  template<typename _Codecvt, typename _Elem = wchar_t,
+	   typename _Wide_alloc = allocator<_Elem>,
+	   typename _Byte_alloc = allocator<char>>
+    class wstring_convert
+    {
+    public:
+      typedef basic_string<char, char_traits<char>, _Byte_alloc>   byte_string;
+      typedef basic_string<_Elem, char_traits<_Elem>, _Wide_alloc> wide_string;
+      typedef typename _Codecvt::state_type 			   state_type;
+      typedef typename wide_string::traits_type::int_type	   int_type;
+
+      /// Default constructor.
+      wstring_convert() : _M_cvt(new _Codecvt()) { }
+
+      /** Constructor.
+       *
+       * @param  __pcvt The facet to use for conversions.
+       *
+       * Takes ownership of @p __pcvt and will delete it in the destructor.
+       */
+      explicit
+      wstring_convert(_Codecvt* __pcvt) : _M_cvt(__pcvt, "wstring_convert")
+      { }
+
+      /** Construct with an initial converstion state.
+       *
+       * @param  __pcvt The facet to use for conversions.
+       * @param  __state Initial conversion state.
+       *
+       * Takes ownership of @p __pcvt and will delete it in the destructor.
+       * The object's conversion state will persist between conversions.
+       */
+      wstring_convert(_Codecvt* __pcvt, state_type __state)
+      : _M_cvt(__pcvt, "wstring_convert"),
+	_M_state(__state), _M_with_cvtstate(true)
+      { }
+
+      /** Construct with error strings.
+       *
+       * @param  __byte_err A string to return on failed conversions.
+       * @param  __wide_err A wide string to return on failed conversions.
+       */
+      explicit
+      wstring_convert(const byte_string& __byte_err,
+		      const wide_string& __wide_err = wide_string())
+      : _M_cvt(new _Codecvt),
+	_M_byte_err_string(__byte_err), _M_wide_err_string(__wide_err),
+	_M_with_strings(true)
+      { }
+
+      ~wstring_convert() = default;
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 2176. Special members for wstring_convert and wbuffer_convert
+      wstring_convert(const wstring_convert&) = delete;
+      wstring_convert& operator=(const wstring_convert&) = delete;
+
+      /// @{ Convert from bytes.
+      wide_string
+      from_bytes(char __byte)
+      {
+	char __bytes[2] = { __byte };
+	return from_bytes(__bytes, __bytes+1);
+      }
+
+      wide_string
+      from_bytes(const char* __ptr)
+      { return from_bytes(__ptr, __ptr+char_traits<char>::length(__ptr)); }
+
+      wide_string
+      from_bytes(const byte_string& __str)
+      {
+	auto __ptr = __str.data();
+	return from_bytes(__ptr, __ptr + __str.size());
+      }
+
+      wide_string
+      from_bytes(const char* __first, const char* __last)
+      {
+	if (!_M_with_cvtstate)
+	  _M_state = state_type();
+	wide_string __out{ _M_wide_err_string.get_allocator() };
+	if (__str_codecvt_in(__first, __last, __out, *_M_cvt, _M_state,
+			     _M_count))
+	  return __out;
+	if (_M_with_strings)
+	  return _M_wide_err_string;
+	__throw_range_error("wstring_convert::from_bytes");
+      }
+      /// @}
+
+      /// @{ Convert to bytes.
+      byte_string
+      to_bytes(_Elem __wchar)
+      {
+	_Elem __wchars[2] = { __wchar };
+	return to_bytes(__wchars, __wchars+1);
+      }
+
+      byte_string
+      to_bytes(const _Elem* __ptr)
+      {
+	return to_bytes(__ptr, __ptr+wide_string::traits_type::length(__ptr));
+      }
+
+      byte_string
+      to_bytes(const wide_string& __wstr)
+      {
+	auto __ptr = __wstr.data();
+	return to_bytes(__ptr, __ptr + __wstr.size());
+      }
+
+      byte_string
+      to_bytes(const _Elem* __first, const _Elem* __last)
+      {
+	if (!_M_with_cvtstate)
+	  _M_state = state_type();
+	byte_string __out{ _M_byte_err_string.get_allocator() };
+	if (__str_codecvt_out(__first, __last, __out, *_M_cvt, _M_state,
+			      _M_count))
+	  return __out;
+	if (_M_with_strings)
+	  return _M_byte_err_string;
+	__throw_range_error("wstring_convert::to_bytes");
+      }
+      /// @}
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 2174. wstring_convert::converted() should be noexcept
+      /// The number of elements successfully converted in the last conversion.
+      size_t converted() const noexcept { return _M_count; }
+
+      /// The final conversion state of the last conversion.
+      state_type state() const { return _M_state; }
+
+    private:
+      __detail::_Scoped_ptr<_Codecvt>	_M_cvt;
+      byte_string		_M_byte_err_string;
+      wide_string		_M_wide_err_string;
+      state_type		_M_state = state_type();
+      size_t			_M_count = 0;
+      bool			_M_with_cvtstate = false;
+      bool			_M_with_strings = false;
+    };
+
+_GLIBCXX_END_NAMESPACE_CXX11
+
+  /// Buffer conversions
+  template<typename _Codecvt, typename _Elem = wchar_t,
+	   typename _Tr = char_traits<_Elem>>
+    class wbuffer_convert : public basic_streambuf<_Elem, _Tr>
+    {
+      typedef basic_streambuf<_Elem, _Tr> _Wide_streambuf;
+
+    public:
+      typedef typename _Codecvt::state_type state_type;
+
+      /// Default constructor.
+      wbuffer_convert() : wbuffer_convert(nullptr) { }
+
+      /** Constructor.
+       *
+       * @param  __bytebuf The underlying byte stream buffer.
+       * @param  __pcvt    The facet to use for conversions.
+       * @param  __state   Initial conversion state.
+       *
+       * Takes ownership of @p __pcvt and will delete it in the destructor.
+       */
+      explicit
+      wbuffer_convert(streambuf* __bytebuf, _Codecvt* __pcvt = new _Codecvt,
+		      state_type __state = state_type())
+      : _M_buf(__bytebuf), _M_cvt(__pcvt, "wbuffer_convert"),
+	_M_state(__state), _M_always_noconv(_M_cvt->always_noconv())
+      {
+	if (_M_buf)
+	  {
+	    this->setp(_M_put_area, _M_put_area + _S_buffer_length);
+	    this->setg(_M_get_area + _S_putback_length,
+		       _M_get_area + _S_putback_length,
+		       _M_get_area + _S_putback_length);
+	  }
+      }
+
+      ~wbuffer_convert() = default;
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 2176. Special members for wstring_convert and wbuffer_convert
+      wbuffer_convert(const wbuffer_convert&) = delete;
+      wbuffer_convert& operator=(const wbuffer_convert&) = delete;
+
+      streambuf* rdbuf() const noexcept { return _M_buf; }
+
+      streambuf*
+      rdbuf(streambuf *__bytebuf) noexcept
+      {
+	auto __prev = _M_buf;
+	_M_buf = __bytebuf;
+	return __prev;
+      }
+
+      /// The conversion state following the last conversion.
+      state_type state() const noexcept { return _M_state; }
+
+    protected:
+      int
+      sync()
+      { return _M_buf && _M_conv_put() && !_M_buf->pubsync() ? 0 : -1; }
+
+      typename _Wide_streambuf::int_type
+      overflow(typename _Wide_streambuf::int_type __out)
+      {
+	if (!_M_buf || !_M_conv_put())
+	  return _Tr::eof();
+	else if (!_Tr::eq_int_type(__out, _Tr::eof()))
+	  return this->sputc(__out);
+	return _Tr::not_eof(__out);
+      }
+
+      typename _Wide_streambuf::int_type
+      underflow()
+      {
+	if (!_M_buf)
+	  return _Tr::eof();
+
+	if (this->gptr() < this->egptr() || (_M_buf && _M_conv_get()))
+	  return _Tr::to_int_type(*this->gptr());
+	else
+	  return _Tr::eof();
+      }
+
+      streamsize
+      xsputn(const typename _Wide_streambuf::char_type* __s, streamsize __n)
+      {
+	if (!_M_buf || __n == 0)
+	  return 0;
+	streamsize __done = 0;
+	do
+	{
+	  auto __nn = std::min<streamsize>(this->epptr() - this->pptr(),
+					   __n - __done);
+	  _Tr::copy(this->pptr(), __s + __done, __nn);
+	  this->pbump(__nn);
+	  __done += __nn;
+	} while (__done < __n && _M_conv_put());
+	return __done;
+      }
+
+    private:
+      // fill the get area from converted contents of the byte stream buffer
+      bool
+      _M_conv_get()
+      {
+	const streamsize __pb1 = this->gptr() - this->eback();
+	const streamsize __pb2 = _S_putback_length;
+	const streamsize __npb = std::min(__pb1, __pb2);
+
+	_Tr::move(_M_get_area + _S_putback_length - __npb,
+		  this->gptr() - __npb, __npb);
+
+	streamsize __nbytes = sizeof(_M_get_buf) - _M_unconv;
+	__nbytes = std::min(__nbytes, _M_buf->in_avail());
+	if (__nbytes < 1)
+	  __nbytes = 1;
+	__nbytes = _M_buf->sgetn(_M_get_buf + _M_unconv, __nbytes);
+	if (__nbytes < 1)
+	  return false;
+	__nbytes += _M_unconv;
+
+	// convert _M_get_buf into _M_get_area
+
+	_Elem* __outbuf = _M_get_area + _S_putback_length;
+	_Elem* __outnext = __outbuf;
+	const char* __bnext = _M_get_buf;
+
+	codecvt_base::result __result;
+	if (_M_always_noconv)
+	  __result = codecvt_base::noconv;
+	else
+	  {
+	    _Elem* __outend = _M_get_area + _S_buffer_length;
+
+	    __result = _M_cvt->in(_M_state,
+				  __bnext, __bnext + __nbytes, __bnext,
+				  __outbuf, __outend, __outnext);
+	  }
+
+	if (__result == codecvt_base::noconv)
+	  {
+	    // cast is safe because noconv means _Elem is same type as char
+	    auto __get_buf = reinterpret_cast<const _Elem*>(_M_get_buf);
+	    _Tr::copy(__outbuf, __get_buf, __nbytes);
+	    _M_unconv = 0;
+	    return true;
+	  }
+
+	if ((_M_unconv = _M_get_buf + __nbytes - __bnext))
+	  char_traits<char>::move(_M_get_buf, __bnext, _M_unconv);
+
+	this->setg(__outbuf, __outbuf, __outnext);
+
+	return __result != codecvt_base::error;
+      }
+
+      // unused
+      bool
+      _M_put(...)
+      { return false; }
+
+      bool
+      _M_put(const char* __p, streamsize __n)
+      {
+	if (_M_buf->sputn(__p, __n) < __n)
+	  return false;
+	return true;
+      }
+
+      // convert the put area and write to the byte stream buffer
+      bool
+      _M_conv_put()
+      {
+	_Elem* const __first = this->pbase();
+	const _Elem* const __last = this->pptr();
+	const streamsize __pending = __last - __first;
+
+	if (_M_always_noconv)
+	  return _M_put(__first, __pending);
+
+	char __outbuf[2 * _S_buffer_length];
+
+	const _Elem* __next = __first;
+	const _Elem* __start;
+	do
+	  {
+	    __start = __next;
+	    char* __outnext = __outbuf;
+	    char* const __outlast = __outbuf + sizeof(__outbuf);
+	    auto __result = _M_cvt->out(_M_state, __next, __last, __next,
+					__outnext, __outlast, __outnext);
+	    if (__result == codecvt_base::error)
+	      return false;
+	    else if (__result == codecvt_base::noconv)
+	      return _M_put(__next, __pending);
+
+	    if (!_M_put(__outbuf, __outnext - __outbuf))
+	      return false;
+	  }
+	while (__next != __last && __next != __start);
+
+	if (__next != __last)
+	  _Tr::move(__first, __next, __last - __next);
+
+	this->pbump(__first - __next);
+	return __next != __first;
+      }
+
+      streambuf*			_M_buf;
+      __detail::_Scoped_ptr<_Codecvt>	_M_cvt;
+      state_type			_M_state;
+
+      static const streamsize	_S_buffer_length = 32;
+      static const streamsize	_S_putback_length = 3;
+      _Elem                     _M_put_area[_S_buffer_length];
+      _Elem                     _M_get_area[_S_buffer_length];
+      streamsize		_M_unconv = 0;
+      char			_M_get_buf[_S_buffer_length-_S_putback_length];
+      bool			_M_always_noconv;
+    };
+
+  /// @} group locales
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif // __cplusplus
+
+#endif /* _LOCALE_CONV_H */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@locale_conv.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@locale_conv.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@locale_facets.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@locale_facets.h
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@locale_facets.h
@@ -0,0 +1,2689 @@
+// Locale support -*- C++ -*-
+
+// Copyright (C) 1997-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/locale_facets.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{locale}
+ */
+
+//
+// ISO C++ 14882: 22.1  Locales
+//
+
+#ifndef _LOCALE_FACETS_H
+#define _LOCALE_FACETS_H 1
+
+#pragma GCC system_header
+
+#include <cwctype>	// For wctype_t
+#include <cctype>
+#include <bits/ctype_base.h>
+#include <iosfwd>
+#include <bits/ios_base.h>  // For ios_base, ios_base::iostate
+#include <streambuf>
+#include <bits/cpp_type_traits.h>
+#include <ext/type_traits.h>
+#include <ext/numeric_traits.h>
+#include <bits/streambuf_iterator.h>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+// Number of standard facets (for narrow characters only)
+#define  _GLIBCXX_NUM_FACETS 14
+
+// Number of duplicated facets for cxx11 ABI
+#define  _GLIBCXX_NUM_CXX11_FACETS (_GLIBCXX_USE_DUAL_ABI ? 8 : 0)
+
+// codecvt<char16_t> and codecvt<char32_t>
+#ifdef _GLIBCXX_USE_CHAR8_T
+# define _GLIBCXX_NUM_UNICODE_FACETS 4
+#else
+# define _GLIBCXX_NUM_UNICODE_FACETS 2
+#endif
+
+// Facets duplicated for alt128 long double format
+// num_get, num_put, money_get, money_put (+ cxx11 money_get, money_put)
+#define _GLIBCXX_NUM_LBDL_ALT128_FACETS (4 + (_GLIBCXX_USE_DUAL_ABI ? 2 : 0))
+
+  // Convert string to numeric value of type _Tp and store results.
+  // NB: This is specialized for all required types, there is no
+  // generic definition.
+  template<typename _Tp>
+    void
+    __convert_to_v(const char*, _Tp&, ios_base::iostate&,
+		   const __c_locale&) throw();
+
+  // Explicit specializations for required types.
+  template<>
+    void
+    __convert_to_v(const char*, float&, ios_base::iostate&,
+		   const __c_locale&) throw();
+
+  template<>
+    void
+    __convert_to_v(const char*, double&, ios_base::iostate&,
+		   const __c_locale&) throw();
+
+  template<>
+    void
+    __convert_to_v(const char*, long double&, ios_base::iostate&,
+		   const __c_locale&) throw();
+
+  // NB: __pad is a struct, rather than a function, so it can be
+  // partially-specialized.
+  template<typename _CharT, typename _Traits>
+    struct __pad
+    {
+      static void
+      _S_pad(ios_base& __io, _CharT __fill, _CharT* __news,
+	     const _CharT* __olds, streamsize __newlen, streamsize __oldlen);
+    };
+
+  // Used by both numeric and monetary facets.
+  // Inserts "group separator" characters into an array of characters.
+  // It's recursive, one iteration per group.  It moves the characters
+  // in the buffer this way: "xxxx12345" -> "12,345xxx".  Call this
+  // only with __gsize != 0.
+  template<typename _CharT>
+    _CharT*
+    __add_grouping(_CharT* __s, _CharT __sep,
+		   const char* __gbeg, size_t __gsize,
+		   const _CharT* __first, const _CharT* __last);
+
+  // This template permits specializing facet output code for
+  // ostreambuf_iterator.  For ostreambuf_iterator, sputn is
+  // significantly more efficient than incrementing iterators.
+  template<typename _CharT>
+    inline
+    ostreambuf_iterator<_CharT>
+    __write(ostreambuf_iterator<_CharT> __s, const _CharT* __ws, int __len)
+    {
+      __s._M_put(__ws, __len);
+      return __s;
+    }
+
+  // This is the unspecialized form of the template.
+  template<typename _CharT, typename _OutIter>
+    inline
+    _OutIter
+    __write(_OutIter __s, const _CharT* __ws, int __len)
+    {
+      for (int __j = 0; __j < __len; __j++, ++__s)
+	*__s = __ws[__j];
+      return __s;
+    }
+
+
+  // 22.2.1.1  Template class ctype
+  // Include host and configuration specific ctype enums for ctype_base.
+
+  /**
+   *  @brief  Common base for ctype facet
+   *
+   *  This template class provides implementations of the public functions
+   *  that forward to the protected virtual functions.
+   *
+   *  This template also provides abstract stubs for the protected virtual
+   *  functions.
+  */
+  template<typename _CharT>
+    class __ctype_abstract_base : public locale::facet, public ctype_base
+    {
+    public:
+      // Types:
+      /// Typedef for the template parameter
+      typedef _CharT char_type;
+
+      /**
+       *  @brief  Test char_type classification.
+       *
+       *  This function finds a mask M for @a __c and compares it to
+       *  mask @a __m.  It does so by returning the value of
+       *  ctype<char_type>::do_is().
+       *
+       *  @param __c  The char_type to compare the mask of.
+       *  @param __m  The mask to compare against.
+       *  @return  (M & __m) != 0.
+      */
+      bool
+      is(mask __m, char_type __c) const
+      { return this->do_is(__m, __c); }
+
+      /**
+       *  @brief  Return a mask array.
+       *
+       *  This function finds the mask for each char_type in the range [lo,hi)
+       *  and successively writes it to vec.  vec must have as many elements
+       *  as the char array.  It does so by returning the value of
+       *  ctype<char_type>::do_is().
+       *
+       *  @param __lo  Pointer to start of range.
+       *  @param __hi  Pointer to end of range.
+       *  @param __vec  Pointer to an array of mask storage.
+       *  @return  @a __hi.
+      */
+      const char_type*
+      is(const char_type *__lo, const char_type *__hi, mask *__vec) const
+      { return this->do_is(__lo, __hi, __vec); }
+
+      /**
+       *  @brief  Find char_type matching a mask
+       *
+       *  This function searches for and returns the first char_type c in
+       *  [lo,hi) for which is(m,c) is true.  It does so by returning
+       *  ctype<char_type>::do_scan_is().
+       *
+       *  @param __m  The mask to compare against.
+       *  @param __lo  Pointer to start of range.
+       *  @param __hi  Pointer to end of range.
+       *  @return  Pointer to matching char_type if found, else @a __hi.
+      */
+      const char_type*
+      scan_is(mask __m, const char_type* __lo, const char_type* __hi) const
+      { return this->do_scan_is(__m, __lo, __hi); }
+
+      /**
+       *  @brief  Find char_type not matching a mask
+       *
+       *  This function searches for and returns the first char_type c in
+       *  [lo,hi) for which is(m,c) is false.  It does so by returning
+       *  ctype<char_type>::do_scan_not().
+       *
+       *  @param __m  The mask to compare against.
+       *  @param __lo  Pointer to first char in range.
+       *  @param __hi  Pointer to end of range.
+       *  @return  Pointer to non-matching char if found, else @a __hi.
+      */
+      const char_type*
+      scan_not(mask __m, const char_type* __lo, const char_type* __hi) const
+      { return this->do_scan_not(__m, __lo, __hi); }
+
+      /**
+       *  @brief  Convert to uppercase.
+       *
+       *  This function converts the argument to uppercase if possible.
+       *  If not possible (for example, '2'), returns the argument.  It does
+       *  so by returning ctype<char_type>::do_toupper().
+       *
+       *  @param __c  The char_type to convert.
+       *  @return  The uppercase char_type if convertible, else @a __c.
+      */
+      char_type
+      toupper(char_type __c) const
+      { return this->do_toupper(__c); }
+
+      /**
+       *  @brief  Convert array to uppercase.
+       *
+       *  This function converts each char_type in the range [lo,hi) to
+       *  uppercase if possible.  Other elements remain untouched.  It does so
+       *  by returning ctype<char_type>:: do_toupper(lo, hi).
+       *
+       *  @param __lo  Pointer to start of range.
+       *  @param __hi  Pointer to end of range.
+       *  @return  @a __hi.
+      */
+      const char_type*
+      toupper(char_type *__lo, const char_type* __hi) const
+      { return this->do_toupper(__lo, __hi); }
+
+      /**
+       *  @brief  Convert to lowercase.
+       *
+       *  This function converts the argument to lowercase if possible.  If
+       *  not possible (for example, '2'), returns the argument.  It does so
+       *  by returning ctype<char_type>::do_tolower(c).
+       *
+       *  @param __c  The char_type to convert.
+       *  @return  The lowercase char_type if convertible, else @a __c.
+      */
+      char_type
+      tolower(char_type __c) const
+      { return this->do_tolower(__c); }
+
+      /**
+       *  @brief  Convert array to lowercase.
+       *
+       *  This function converts each char_type in the range [__lo,__hi) to
+       *  lowercase if possible.  Other elements remain untouched.  It does so
+       *  by returning ctype<char_type>:: do_tolower(__lo, __hi).
+       *
+       *  @param __lo  Pointer to start of range.
+       *  @param __hi  Pointer to end of range.
+       *  @return  @a __hi.
+      */
+      const char_type*
+      tolower(char_type* __lo, const char_type* __hi) const
+      { return this->do_tolower(__lo, __hi); }
+
+      /**
+       *  @brief  Widen char to char_type
+       *
+       *  This function converts the char argument to char_type using the
+       *  simplest reasonable transformation.  It does so by returning
+       *  ctype<char_type>::do_widen(c).
+       *
+       *  Note: this is not what you want for codepage conversions.  See
+       *  codecvt for that.
+       *
+       *  @param __c  The char to convert.
+       *  @return  The converted char_type.
+      */
+      char_type
+      widen(char __c) const
+      { return this->do_widen(__c); }
+
+      /**
+       *  @brief  Widen array to char_type
+       *
+       *  This function converts each char in the input to char_type using the
+       *  simplest reasonable transformation.  It does so by returning
+       *  ctype<char_type>::do_widen(c).
+       *
+       *  Note: this is not what you want for codepage conversions.  See
+       *  codecvt for that.
+       *
+       *  @param __lo  Pointer to start of range.
+       *  @param __hi  Pointer to end of range.
+       *  @param __to  Pointer to the destination array.
+       *  @return  @a __hi.
+      */
+      const char*
+      widen(const char* __lo, const char* __hi, char_type* __to) const
+      { return this->do_widen(__lo, __hi, __to); }
+
+      /**
+       *  @brief  Narrow char_type to char
+       *
+       *  This function converts the char_type to char using the simplest
+       *  reasonable transformation.  If the conversion fails, dfault is
+       *  returned instead.  It does so by returning
+       *  ctype<char_type>::do_narrow(__c).
+       *
+       *  Note: this is not what you want for codepage conversions.  See
+       *  codecvt for that.
+       *
+       *  @param __c  The char_type to convert.
+       *  @param __dfault  Char to return if conversion fails.
+       *  @return  The converted char.
+      */
+      char
+      narrow(char_type __c, char __dfault) const
+      { return this->do_narrow(__c, __dfault); }
+
+      /**
+       *  @brief  Narrow array to char array
+       *
+       *  This function converts each char_type in the input to char using the
+       *  simplest reasonable transformation and writes the results to the
+       *  destination array.  For any char_type in the input that cannot be
+       *  converted, @a dfault is used instead.  It does so by returning
+       *  ctype<char_type>::do_narrow(__lo, __hi, __dfault, __to).
+       *
+       *  Note: this is not what you want for codepage conversions.  See
+       *  codecvt for that.
+       *
+       *  @param __lo  Pointer to start of range.
+       *  @param __hi  Pointer to end of range.
+       *  @param __dfault  Char to use if conversion fails.
+       *  @param __to  Pointer to the destination array.
+       *  @return  @a __hi.
+      */
+      const char_type*
+      narrow(const char_type* __lo, const char_type* __hi,
+	      char __dfault, char* __to) const
+      { return this->do_narrow(__lo, __hi, __dfault, __to); }
+
+    protected:
+      explicit
+      __ctype_abstract_base(size_t __refs = 0): facet(__refs) { }
+
+      virtual
+      ~__ctype_abstract_base() { }
+
+      /**
+       *  @brief  Test char_type classification.
+       *
+       *  This function finds a mask M for @a c and compares it to mask @a m.
+       *
+       *  do_is() is a hook for a derived facet to change the behavior of
+       *  classifying.  do_is() must always return the same result for the
+       *  same input.
+       *
+       *  @param __c  The char_type to find the mask of.
+       *  @param __m  The mask to compare against.
+       *  @return  (M & __m) != 0.
+      */
+      virtual bool
+      do_is(mask __m, char_type __c) const = 0;
+
+      /**
+       *  @brief  Return a mask array.
+       *
+       *  This function finds the mask for each char_type in the range [lo,hi)
+       *  and successively writes it to vec.  vec must have as many elements
+       *  as the input.
+       *
+       *  do_is() is a hook for a derived facet to change the behavior of
+       *  classifying.  do_is() must always return the same result for the
+       *  same input.
+       *
+       *  @param __lo  Pointer to start of range.
+       *  @param __hi  Pointer to end of range.
+       *  @param __vec  Pointer to an array of mask storage.
+       *  @return  @a __hi.
+      */
+      virtual const char_type*
+      do_is(const char_type* __lo, const char_type* __hi,
+	    mask* __vec) const = 0;
+
+      /**
+       *  @brief  Find char_type matching mask
+       *
+       *  This function searches for and returns the first char_type c in
+       *  [__lo,__hi) for which is(__m,c) is true.
+       *
+       *  do_scan_is() is a hook for a derived facet to change the behavior of
+       *  match searching.  do_is() must always return the same result for the
+       *  same input.
+       *
+       *  @param __m  The mask to compare against.
+       *  @param __lo  Pointer to start of range.
+       *  @param __hi  Pointer to end of range.
+       *  @return  Pointer to a matching char_type if found, else @a __hi.
+      */
+      virtual const char_type*
+      do_scan_is(mask __m, const char_type* __lo,
+		 const char_type* __hi) const = 0;
+
+      /**
+       *  @brief  Find char_type not matching mask
+       *
+       *  This function searches for and returns a pointer to the first
+       *  char_type c of [lo,hi) for which is(m,c) is false.
+       *
+       *  do_scan_is() is a hook for a derived facet to change the behavior of
+       *  match searching.  do_is() must always return the same result for the
+       *  same input.
+       *
+       *  @param __m  The mask to compare against.
+       *  @param __lo  Pointer to start of range.
+       *  @param __hi  Pointer to end of range.
+       *  @return  Pointer to a non-matching char_type if found, else @a __hi.
+      */
+      virtual const char_type*
+      do_scan_not(mask __m, const char_type* __lo,
+		  const char_type* __hi) const = 0;
+
+      /**
+       *  @brief  Convert to uppercase.
+       *
+       *  This virtual function converts the char_type argument to uppercase
+       *  if possible.  If not possible (for example, '2'), returns the
+       *  argument.
+       *
+       *  do_toupper() is a hook for a derived facet to change the behavior of
+       *  uppercasing.  do_toupper() must always return the same result for
+       *  the same input.
+       *
+       *  @param __c  The char_type to convert.
+       *  @return  The uppercase char_type if convertible, else @a __c.
+      */
+      virtual char_type
+      do_toupper(char_type __c) const = 0;
+
+      /**
+       *  @brief  Convert array to uppercase.
+       *
+       *  This virtual function converts each char_type in the range [__lo,__hi)
+       *  to uppercase if possible.  Other elements remain untouched.
+       *
+       *  do_toupper() is a hook for a derived facet to change the behavior of
+       *  uppercasing.  do_toupper() must always return the same result for
+       *  the same input.
+       *
+       *  @param __lo  Pointer to start of range.
+       *  @param __hi  Pointer to end of range.
+       *  @return  @a __hi.
+      */
+      virtual const char_type*
+      do_toupper(char_type* __lo, const char_type* __hi) const = 0;
+
+      /**
+       *  @brief  Convert to lowercase.
+       *
+       *  This virtual function converts the argument to lowercase if
+       *  possible.  If not possible (for example, '2'), returns the argument.
+       *
+       *  do_tolower() is a hook for a derived facet to change the behavior of
+       *  lowercasing.  do_tolower() must always return the same result for
+       *  the same input.
+       *
+       *  @param __c  The char_type to convert.
+       *  @return  The lowercase char_type if convertible, else @a __c.
+      */
+      virtual char_type
+      do_tolower(char_type __c) const = 0;
+
+      /**
+       *  @brief  Convert array to lowercase.
+       *
+       *  This virtual function converts each char_type in the range [__lo,__hi)
+       *  to lowercase if possible.  Other elements remain untouched.
+       *
+       *  do_tolower() is a hook for a derived facet to change the behavior of
+       *  lowercasing.  do_tolower() must always return the same result for
+       *  the same input.
+       *
+       *  @param __lo  Pointer to start of range.
+       *  @param __hi  Pointer to end of range.
+       *  @return  @a __hi.
+      */
+      virtual const char_type*
+      do_tolower(char_type* __lo, const char_type* __hi) const = 0;
+
+      /**
+       *  @brief  Widen char
+       *
+       *  This virtual function converts the char to char_type using the
+       *  simplest reasonable transformation.
+       *
+       *  do_widen() is a hook for a derived facet to change the behavior of
+       *  widening.  do_widen() must always return the same result for the
+       *  same input.
+       *
+       *  Note: this is not what you want for codepage conversions.  See
+       *  codecvt for that.
+       *
+       *  @param __c  The char to convert.
+       *  @return  The converted char_type
+      */
+      virtual char_type
+      do_widen(char __c) const = 0;
+
+      /**
+       *  @brief  Widen char array
+       *
+       *  This function converts each char in the input to char_type using the
+       *  simplest reasonable transformation.
+       *
+       *  do_widen() is a hook for a derived facet to change the behavior of
+       *  widening.  do_widen() must always return the same result for the
+       *  same input.
+       *
+       *  Note: this is not what you want for codepage conversions.  See
+       *  codecvt for that.
+       *
+       *  @param __lo  Pointer to start range.
+       *  @param __hi  Pointer to end of range.
+       *  @param __to  Pointer to the destination array.
+       *  @return  @a __hi.
+      */
+      virtual const char*
+      do_widen(const char* __lo, const char* __hi, char_type* __to) const = 0;
+
+      /**
+       *  @brief  Narrow char_type to char
+       *
+       *  This virtual function converts the argument to char using the
+       *  simplest reasonable transformation.  If the conversion fails, dfault
+       *  is returned instead.
+       *
+       *  do_narrow() is a hook for a derived facet to change the behavior of
+       *  narrowing.  do_narrow() must always return the same result for the
+       *  same input.
+       *
+       *  Note: this is not what you want for codepage conversions.  See
+       *  codecvt for that.
+       *
+       *  @param __c  The char_type to convert.
+       *  @param __dfault  Char to return if conversion fails.
+       *  @return  The converted char.
+      */
+      virtual char
+      do_narrow(char_type __c, char __dfault) const = 0;
+
+      /**
+       *  @brief  Narrow char_type array to char
+       *
+       *  This virtual function converts each char_type in the range
+       *  [__lo,__hi) to char using the simplest reasonable
+       *  transformation and writes the results to the destination
+       *  array.  For any element in the input that cannot be
+       *  converted, @a __dfault is used instead.
+       *
+       *  do_narrow() is a hook for a derived facet to change the behavior of
+       *  narrowing.  do_narrow() must always return the same result for the
+       *  same input.
+       *
+       *  Note: this is not what you want for codepage conversions.  See
+       *  codecvt for that.
+       *
+       *  @param __lo  Pointer to start of range.
+       *  @param __hi  Pointer to end of range.
+       *  @param __dfault  Char to use if conversion fails.
+       *  @param __to  Pointer to the destination array.
+       *  @return  @a __hi.
+      */
+      virtual const char_type*
+      do_narrow(const char_type* __lo, const char_type* __hi,
+		char __dfault, char* __to) const = 0;
+    };
+
+  /**
+   *  @brief  Primary class template ctype facet.
+   *  @ingroup locales
+   *
+   *  This template class defines classification and conversion functions for
+   *  character sets.  It wraps cctype functionality.  Ctype gets used by
+   *  streams for many I/O operations.
+   *
+   *  This template provides the protected virtual functions the developer
+   *  will have to replace in a derived class or specialization to make a
+   *  working facet.  The public functions that access them are defined in
+   *  __ctype_abstract_base, to allow for implementation flexibility.  See
+   *  ctype<wchar_t> for an example.  The functions are documented in
+   *  __ctype_abstract_base.
+   *
+   *  Note: implementations are provided for all the protected virtual
+   *  functions, but will likely not be useful.
+  */
+  template<typename _CharT>
+    class ctype : public __ctype_abstract_base<_CharT>
+    {
+    public:
+      // Types:
+      typedef _CharT			char_type;
+      typedef typename __ctype_abstract_base<_CharT>::mask mask;
+
+      /// The facet id for ctype<char_type>
+      static locale::id			id;
+
+      explicit
+      ctype(size_t __refs = 0) : __ctype_abstract_base<_CharT>(__refs) { }
+
+   protected:
+      virtual
+      ~ctype();
+
+      virtual bool
+      do_is(mask __m, char_type __c) const;
+
+      virtual const char_type*
+      do_is(const char_type* __lo, const char_type* __hi, mask* __vec) const;
+
+      virtual const char_type*
+      do_scan_is(mask __m, const char_type* __lo, const char_type* __hi) const;
+
+      virtual const char_type*
+      do_scan_not(mask __m, const char_type* __lo,
+		  const char_type* __hi) const;
+
+      virtual char_type
+      do_toupper(char_type __c) const;
+
+      virtual const char_type*
+      do_toupper(char_type* __lo, const char_type* __hi) const;
+
+      virtual char_type
+      do_tolower(char_type __c) const;
+
+      virtual const char_type*
+      do_tolower(char_type* __lo, const char_type* __hi) const;
+
+      virtual char_type
+      do_widen(char __c) const;
+
+      virtual const char*
+      do_widen(const char* __lo, const char* __hi, char_type* __dest) const;
+
+      virtual char
+      do_narrow(char_type, char __dfault) const;
+
+      virtual const char_type*
+      do_narrow(const char_type* __lo, const char_type* __hi,
+		char __dfault, char* __to) const;
+    };
+
+  template<typename _CharT>
+    locale::id ctype<_CharT>::id;
+
+  // Incomplete to provide a compile time diagnostics for common misuse
+  // of [locale.convenience] functions with basic_string as a character type.
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    class ctype<basic_string<_CharT, _Traits, _Alloc> >;
+
+  /**
+   *  @brief  The ctype<char> specialization.
+   *  @ingroup locales
+   *
+   *  This class defines classification and conversion functions for
+   *  the char type.  It gets used by char streams for many I/O
+   *  operations.  The char specialization provides a number of
+   *  optimizations as well.
+  */
+  template<>
+    class ctype<char> : public locale::facet, public ctype_base
+    {
+    public:
+      // Types:
+      /// Typedef for the template parameter char.
+      typedef char		char_type;
+
+    protected:
+      // Data Members:
+      __c_locale		_M_c_locale_ctype;
+      bool			_M_del;
+      __to_type			_M_toupper;
+      __to_type			_M_tolower;
+      const mask*		_M_table;
+      mutable char		_M_widen_ok;
+      mutable char		_M_widen[1 + static_cast<unsigned char>(-1)];
+      mutable char		_M_narrow[1 + static_cast<unsigned char>(-1)];
+      mutable char		_M_narrow_ok;	// 0 uninitialized, 1 init,
+						// 2 memcpy can't be used
+
+    public:
+      /// The facet id for ctype<char>
+      static locale::id        id;
+      /// The size of the mask table.  It is SCHAR_MAX + 1.
+      static const size_t      table_size = 1 + static_cast<unsigned char>(-1);
+
+      /**
+       *  @brief  Constructor performs initialization.
+       *
+       *  This is the constructor provided by the standard.
+       *
+       *  @param __table If non-zero, table is used as the per-char mask.
+       *               Else classic_table() is used.
+       *  @param __del   If true, passes ownership of table to this facet.
+       *  @param __refs  Passed to the base facet class.
+      */
+      explicit
+      ctype(const mask* __table = 0, bool __del = false, size_t __refs = 0);
+
+      /**
+       *  @brief  Constructor performs static initialization.
+       *
+       *  This constructor is used to construct the initial C locale facet.
+       *
+       *  @param __cloc  Handle to C locale data.
+       *  @param __table If non-zero, table is used as the per-char mask.
+       *  @param __del   If true, passes ownership of table to this facet.
+       *  @param __refs  Passed to the base facet class.
+      */
+      explicit
+      ctype(__c_locale __cloc, const mask* __table = 0, bool __del = false,
+	    size_t __refs = 0);
+
+      /**
+       *  @brief  Test char classification.
+       *
+       *  This function compares the mask table[c] to @a __m.
+       *
+       *  @param __c  The char to compare the mask of.
+       *  @param __m  The mask to compare against.
+       *  @return  True if __m & table[__c] is true, false otherwise.
+      */
+      inline bool
+      is(mask __m, char __c) const;
+
+      /**
+       *  @brief  Return a mask array.
+       *
+       *  This function finds the mask for each char in the range [lo, hi) and
+       *  successively writes it to vec.  vec must have as many elements as
+       *  the char array.
+       *
+       *  @param __lo  Pointer to start of range.
+       *  @param __hi  Pointer to end of range.
+       *  @param __vec  Pointer to an array of mask storage.
+       *  @return  @a __hi.
+      */
+      inline const char*
+      is(const char* __lo, const char* __hi, mask* __vec) const;
+
+      /**
+       *  @brief  Find char matching a mask
+       *
+       *  This function searches for and returns the first char in [lo,hi) for
+       *  which is(m,char) is true.
+       *
+       *  @param __m  The mask to compare against.
+       *  @param __lo  Pointer to start of range.
+       *  @param __hi  Pointer to end of range.
+       *  @return  Pointer to a matching char if found, else @a __hi.
+      */
+      inline const char*
+      scan_is(mask __m, const char* __lo, const char* __hi) const;
+
+      /**
+       *  @brief  Find char not matching a mask
+       *
+       *  This function searches for and returns a pointer to the first char
+       *  in [__lo,__hi) for which is(m,char) is false.
+       *
+       *  @param __m  The mask to compare against.
+       *  @param __lo  Pointer to start of range.
+       *  @param __hi  Pointer to end of range.
+       *  @return  Pointer to a non-matching char if found, else @a __hi.
+      */
+      inline const char*
+      scan_not(mask __m, const char* __lo, const char* __hi) const;
+
+      /**
+       *  @brief  Convert to uppercase.
+       *
+       *  This function converts the char argument to uppercase if possible.
+       *  If not possible (for example, '2'), returns the argument.
+       *
+       *  toupper() acts as if it returns ctype<char>::do_toupper(c).
+       *  do_toupper() must always return the same result for the same input.
+       *
+       *  @param __c  The char to convert.
+       *  @return  The uppercase char if convertible, else @a __c.
+      */
+      char_type
+      toupper(char_type __c) const
+      { return this->do_toupper(__c); }
+
+      /**
+       *  @brief  Convert array to uppercase.
+       *
+       *  This function converts each char in the range [__lo,__hi) to uppercase
+       *  if possible.  Other chars remain untouched.
+       *
+       *  toupper() acts as if it returns ctype<char>:: do_toupper(__lo, __hi).
+       *  do_toupper() must always return the same result for the same input.
+       *
+       *  @param __lo  Pointer to first char in range.
+       *  @param __hi  Pointer to end of range.
+       *  @return  @a __hi.
+      */
+      const char_type*
+      toupper(char_type *__lo, const char_type* __hi) const
+      { return this->do_toupper(__lo, __hi); }
+
+      /**
+       *  @brief  Convert to lowercase.
+       *
+       *  This function converts the char argument to lowercase if possible.
+       *  If not possible (for example, '2'), returns the argument.
+       *
+       *  tolower() acts as if it returns ctype<char>::do_tolower(__c).
+       *  do_tolower() must always return the same result for the same input.
+       *
+       *  @param __c  The char to convert.
+       *  @return  The lowercase char if convertible, else @a __c.
+      */
+      char_type
+      tolower(char_type __c) const
+      { return this->do_tolower(__c); }
+
+      /**
+       *  @brief  Convert array to lowercase.
+       *
+       *  This function converts each char in the range [lo,hi) to lowercase
+       *  if possible.  Other chars remain untouched.
+       *
+       *  tolower() acts as if it returns ctype<char>:: do_tolower(__lo, __hi).
+       *  do_tolower() must always return the same result for the same input.
+       *
+       *  @param __lo  Pointer to first char in range.
+       *  @param __hi  Pointer to end of range.
+       *  @return  @a __hi.
+      */
+      const char_type*
+      tolower(char_type* __lo, const char_type* __hi) const
+      { return this->do_tolower(__lo, __hi); }
+
+      /**
+       *  @brief  Widen char
+       *
+       *  This function converts the char to char_type using the simplest
+       *  reasonable transformation.  For an underived ctype<char> facet, the
+       *  argument will be returned unchanged.
+       *
+       *  This function works as if it returns ctype<char>::do_widen(c).
+       *  do_widen() must always return the same result for the same input.
+       *
+       *  Note: this is not what you want for codepage conversions.  See
+       *  codecvt for that.
+       *
+       *  @param __c  The char to convert.
+       *  @return  The converted character.
+      */
+      char_type
+      widen(char __c) const
+      {
+	if (_M_widen_ok)
+	  return _M_widen[static_cast<unsigned char>(__c)];
+	this->_M_widen_init();
+	return this->do_widen(__c);
+      }
+
+      /**
+       *  @brief  Widen char array
+       *
+       *  This function converts each char in the input to char using the
+       *  simplest reasonable transformation.  For an underived ctype<char>
+       *  facet, the argument will be copied unchanged.
+       *
+       *  This function works as if it returns ctype<char>::do_widen(c).
+       *  do_widen() must always return the same result for the same input.
+       *
+       *  Note: this is not what you want for codepage conversions.  See
+       *  codecvt for that.
+       *
+       *  @param __lo  Pointer to first char in range.
+       *  @param __hi  Pointer to end of range.
+       *  @param __to  Pointer to the destination array.
+       *  @return  @a __hi.
+      */
+      const char*
+      widen(const char* __lo, const char* __hi, char_type* __to) const
+      {
+	if (_M_widen_ok == 1)
+	  {
+	    if (__builtin_expect(__hi != __lo, true))
+	      __builtin_memcpy(__to, __lo, __hi - __lo);
+	    return __hi;
+	  }
+	if (!_M_widen_ok)
+	  _M_widen_init();
+	return this->do_widen(__lo, __hi, __to);
+      }
+
+      /**
+       *  @brief  Narrow char
+       *
+       *  This function converts the char to char using the simplest
+       *  reasonable transformation.  If the conversion fails, dfault is
+       *  returned instead.  For an underived ctype<char> facet, @a c
+       *  will be returned unchanged.
+       *
+       *  This function works as if it returns ctype<char>::do_narrow(c).
+       *  do_narrow() must always return the same result for the same input.
+       *
+       *  Note: this is not what you want for codepage conversions.  See
+       *  codecvt for that.
+       *
+       *  @param __c  The char to convert.
+       *  @param __dfault  Char to return if conversion fails.
+       *  @return  The converted character.
+      */
+      char
+      narrow(char_type __c, char __dfault) const
+      {
+	if (_M_narrow[static_cast<unsigned char>(__c)])
+	  return _M_narrow[static_cast<unsigned char>(__c)];
+	const char __t = do_narrow(__c, __dfault);
+	if (__t != __dfault)
+	  _M_narrow[static_cast<unsigned char>(__c)] = __t;
+	return __t;
+      }
+
+      /**
+       *  @brief  Narrow char array
+       *
+       *  This function converts each char in the input to char using the
+       *  simplest reasonable transformation and writes the results to the
+       *  destination array.  For any char in the input that cannot be
+       *  converted, @a dfault is used instead.  For an underived ctype<char>
+       *  facet, the argument will be copied unchanged.
+       *
+       *  This function works as if it returns ctype<char>::do_narrow(lo, hi,
+       *  dfault, to).  do_narrow() must always return the same result for the
+       *  same input.
+       *
+       *  Note: this is not what you want for codepage conversions.  See
+       *  codecvt for that.
+       *
+       *  @param __lo  Pointer to start of range.
+       *  @param __hi  Pointer to end of range.
+       *  @param __dfault  Char to use if conversion fails.
+       *  @param __to  Pointer to the destination array.
+       *  @return  @a __hi.
+      */
+      const char_type*
+      narrow(const char_type* __lo, const char_type* __hi,
+	     char __dfault, char* __to) const
+      {
+	if (__builtin_expect(_M_narrow_ok == 1, true))
+	  {
+	    if (__builtin_expect(__hi != __lo, true))
+	      __builtin_memcpy(__to, __lo, __hi - __lo);
+	    return __hi;
+	  }
+	if (!_M_narrow_ok)
+	  _M_narrow_init();
+	return this->do_narrow(__lo, __hi, __dfault, __to);
+      }
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // DR 695. ctype<char>::classic_table() not accessible.
+      /// Returns a pointer to the mask table provided to the constructor, or
+      /// the default from classic_table() if none was provided.
+      const mask*
+      table() const throw()
+      { return _M_table; }
+
+      /// Returns a pointer to the C locale mask table.
+      static const mask*
+      classic_table() throw();
+    protected:
+
+      /**
+       *  @brief  Destructor.
+       *
+       *  This function deletes table() if @a del was true in the
+       *  constructor.
+      */
+      virtual
+      ~ctype();
+
+      /**
+       *  @brief  Convert to uppercase.
+       *
+       *  This virtual function converts the char argument to uppercase if
+       *  possible.  If not possible (for example, '2'), returns the argument.
+       *
+       *  do_toupper() is a hook for a derived facet to change the behavior of
+       *  uppercasing.  do_toupper() must always return the same result for
+       *  the same input.
+       *
+       *  @param __c  The char to convert.
+       *  @return  The uppercase char if convertible, else @a __c.
+      */
+      virtual char_type
+      do_toupper(char_type __c) const;
+
+      /**
+       *  @brief  Convert array to uppercase.
+       *
+       *  This virtual function converts each char in the range [lo,hi) to
+       *  uppercase if possible.  Other chars remain untouched.
+       *
+       *  do_toupper() is a hook for a derived facet to change the behavior of
+       *  uppercasing.  do_toupper() must always return the same result for
+       *  the same input.
+       *
+       *  @param __lo  Pointer to start of range.
+       *  @param __hi  Pointer to end of range.
+       *  @return  @a __hi.
+      */
+      virtual const char_type*
+      do_toupper(char_type* __lo, const char_type* __hi) const;
+
+      /**
+       *  @brief  Convert to lowercase.
+       *
+       *  This virtual function converts the char argument to lowercase if
+       *  possible.  If not possible (for example, '2'), returns the argument.
+       *
+       *  do_tolower() is a hook for a derived facet to change the behavior of
+       *  lowercasing.  do_tolower() must always return the same result for
+       *  the same input.
+       *
+       *  @param __c  The char to convert.
+       *  @return  The lowercase char if convertible, else @a __c.
+      */
+      virtual char_type
+      do_tolower(char_type __c) const;
+
+      /**
+       *  @brief  Convert array to lowercase.
+       *
+       *  This virtual function converts each char in the range [lo,hi) to
+       *  lowercase if possible.  Other chars remain untouched.
+       *
+       *  do_tolower() is a hook for a derived facet to change the behavior of
+       *  lowercasing.  do_tolower() must always return the same result for
+       *  the same input.
+       *
+       *  @param __lo  Pointer to first char in range.
+       *  @param __hi  Pointer to end of range.
+       *  @return  @a __hi.
+      */
+      virtual const char_type*
+      do_tolower(char_type* __lo, const char_type* __hi) const;
+
+      /**
+       *  @brief  Widen char
+       *
+       *  This virtual function converts the char to char using the simplest
+       *  reasonable transformation.  For an underived ctype<char> facet, the
+       *  argument will be returned unchanged.
+       *
+       *  do_widen() is a hook for a derived facet to change the behavior of
+       *  widening.  do_widen() must always return the same result for the
+       *  same input.
+       *
+       *  Note: this is not what you want for codepage conversions.  See
+       *  codecvt for that.
+       *
+       *  @param __c  The char to convert.
+       *  @return  The converted character.
+      */
+      virtual char_type
+      do_widen(char __c) const
+      { return __c; }
+
+      /**
+       *  @brief  Widen char array
+       *
+       *  This function converts each char in the range [lo,hi) to char using
+       *  the simplest reasonable transformation.  For an underived
+       *  ctype<char> facet, the argument will be copied unchanged.
+       *
+       *  do_widen() is a hook for a derived facet to change the behavior of
+       *  widening.  do_widen() must always return the same result for the
+       *  same input.
+       *
+       *  Note: this is not what you want for codepage conversions.  See
+       *  codecvt for that.
+       *
+       *  @param __lo  Pointer to start of range.
+       *  @param __hi  Pointer to end of range.
+       *  @param __to  Pointer to the destination array.
+       *  @return  @a __hi.
+      */
+      virtual const char*
+      do_widen(const char* __lo, const char* __hi, char_type* __to) const
+      {
+	if (__builtin_expect(__hi != __lo, true))
+	  __builtin_memcpy(__to, __lo, __hi - __lo);
+	return __hi;
+      }
+
+      /**
+       *  @brief  Narrow char
+       *
+       *  This virtual function converts the char to char using the simplest
+       *  reasonable transformation.  If the conversion fails, dfault is
+       *  returned instead.  For an underived ctype<char> facet, @a c will be
+       *  returned unchanged.
+       *
+       *  do_narrow() is a hook for a derived facet to change the behavior of
+       *  narrowing.  do_narrow() must always return the same result for the
+       *  same input.
+       *
+       *  Note: this is not what you want for codepage conversions.  See
+       *  codecvt for that.
+       *
+       *  @param __c  The char to convert.
+       *  @param __dfault  Char to return if conversion fails.
+       *  @return  The converted char.
+      */
+      virtual char
+      do_narrow(char_type __c, char __dfault __attribute__((__unused__))) const
+      { return __c; }
+
+      /**
+       *  @brief  Narrow char array to char array
+       *
+       *  This virtual function converts each char in the range [lo,hi) to
+       *  char using the simplest reasonable transformation and writes the
+       *  results to the destination array.  For any char in the input that
+       *  cannot be converted, @a dfault is used instead.  For an underived
+       *  ctype<char> facet, the argument will be copied unchanged.
+       *
+       *  do_narrow() is a hook for a derived facet to change the behavior of
+       *  narrowing.  do_narrow() must always return the same result for the
+       *  same input.
+       *
+       *  Note: this is not what you want for codepage conversions.  See
+       *  codecvt for that.
+       *
+       *  @param __lo  Pointer to start of range.
+       *  @param __hi  Pointer to end of range.
+       *  @param __dfault  Char to use if conversion fails.
+       *  @param __to  Pointer to the destination array.
+       *  @return  @a __hi.
+      */
+      virtual const char_type*
+      do_narrow(const char_type* __lo, const char_type* __hi,
+		char __dfault __attribute__((__unused__)), char* __to) const
+      {
+	if (__builtin_expect(__hi != __lo, true))
+	  __builtin_memcpy(__to, __lo, __hi - __lo);
+	return __hi;
+      }
+
+    private:
+      void _M_narrow_init() const;
+      void _M_widen_init() const;
+    };
+
+#ifdef _GLIBCXX_USE_WCHAR_T
+  /**
+   *  @brief  The ctype<wchar_t> specialization.
+   *  @ingroup locales
+   *
+   *  This class defines classification and conversion functions for the
+   *  wchar_t type.  It gets used by wchar_t streams for many I/O operations.
+   *  The wchar_t specialization provides a number of optimizations as well.
+   *
+   *  ctype<wchar_t> inherits its public methods from
+   *  __ctype_abstract_base<wchar_t>.
+  */
+  template<>
+    class ctype<wchar_t> : public __ctype_abstract_base<wchar_t>
+    {
+    public:
+      // Types:
+      /// Typedef for the template parameter wchar_t.
+      typedef wchar_t		char_type;
+      typedef wctype_t		__wmask_type;
+
+    protected:
+      __c_locale		_M_c_locale_ctype;
+
+      // Pre-computed narrowed and widened chars.
+      bool                      _M_narrow_ok;
+      char                      _M_narrow[128];
+      wint_t                    _M_widen[1 + static_cast<unsigned char>(-1)];
+
+      // Pre-computed elements for do_is.
+      mask                      _M_bit[16];
+      __wmask_type              _M_wmask[16];
+
+    public:
+      // Data Members:
+      /// The facet id for ctype<wchar_t>
+      static locale::id		id;
+
+      /**
+       *  @brief  Constructor performs initialization.
+       *
+       *  This is the constructor provided by the standard.
+       *
+       *  @param __refs  Passed to the base facet class.
+      */
+      explicit
+      ctype(size_t __refs = 0);
+
+      /**
+       *  @brief  Constructor performs static initialization.
+       *
+       *  This constructor is used to construct the initial C locale facet.
+       *
+       *  @param __cloc  Handle to C locale data.
+       *  @param __refs  Passed to the base facet class.
+      */
+      explicit
+      ctype(__c_locale __cloc, size_t __refs = 0);
+
+    protected:
+      __wmask_type
+      _M_convert_to_wmask(const mask __m) const throw();
+
+      /// Destructor
+      virtual
+      ~ctype();
+
+      /**
+       *  @brief  Test wchar_t classification.
+       *
+       *  This function finds a mask M for @a c and compares it to mask @a m.
+       *
+       *  do_is() is a hook for a derived facet to change the behavior of
+       *  classifying.  do_is() must always return the same result for the
+       *  same input.
+       *
+       *  @param __c  The wchar_t to find the mask of.
+       *  @param __m  The mask to compare against.
+       *  @return  (M & __m) != 0.
+      */
+      virtual bool
+      do_is(mask __m, char_type __c) const;
+
+      /**
+       *  @brief  Return a mask array.
+       *
+       *  This function finds the mask for each wchar_t in the range [lo,hi)
+       *  and successively writes it to vec.  vec must have as many elements
+       *  as the input.
+       *
+       *  do_is() is a hook for a derived facet to change the behavior of
+       *  classifying.  do_is() must always return the same result for the
+       *  same input.
+       *
+       *  @param __lo  Pointer to start of range.
+       *  @param __hi  Pointer to end of range.
+       *  @param __vec  Pointer to an array of mask storage.
+       *  @return  @a __hi.
+      */
+      virtual const char_type*
+      do_is(const char_type* __lo, const char_type* __hi, mask* __vec) const;
+
+      /**
+       *  @brief  Find wchar_t matching mask
+       *
+       *  This function searches for and returns the first wchar_t c in
+       *  [__lo,__hi) for which is(__m,c) is true.
+       *
+       *  do_scan_is() is a hook for a derived facet to change the behavior of
+       *  match searching.  do_is() must always return the same result for the
+       *  same input.
+       *
+       *  @param __m  The mask to compare against.
+       *  @param __lo  Pointer to start of range.
+       *  @param __hi  Pointer to end of range.
+       *  @return  Pointer to a matching wchar_t if found, else @a __hi.
+      */
+      virtual const char_type*
+      do_scan_is(mask __m, const char_type* __lo, const char_type* __hi) const;
+
+      /**
+       *  @brief  Find wchar_t not matching mask
+       *
+       *  This function searches for and returns a pointer to the first
+       *  wchar_t c of [__lo,__hi) for which is(__m,c) is false.
+       *
+       *  do_scan_is() is a hook for a derived facet to change the behavior of
+       *  match searching.  do_is() must always return the same result for the
+       *  same input.
+       *
+       *  @param __m  The mask to compare against.
+       *  @param __lo  Pointer to start of range.
+       *  @param __hi  Pointer to end of range.
+       *  @return  Pointer to a non-matching wchar_t if found, else @a __hi.
+      */
+      virtual const char_type*
+      do_scan_not(mask __m, const char_type* __lo,
+		  const char_type* __hi) const;
+
+      /**
+       *  @brief  Convert to uppercase.
+       *
+       *  This virtual function converts the wchar_t argument to uppercase if
+       *  possible.  If not possible (for example, '2'), returns the argument.
+       *
+       *  do_toupper() is a hook for a derived facet to change the behavior of
+       *  uppercasing.  do_toupper() must always return the same result for
+       *  the same input.
+       *
+       *  @param __c  The wchar_t to convert.
+       *  @return  The uppercase wchar_t if convertible, else @a __c.
+      */
+      virtual char_type
+      do_toupper(char_type __c) const;
+
+      /**
+       *  @brief  Convert array to uppercase.
+       *
+       *  This virtual function converts each wchar_t in the range [lo,hi) to
+       *  uppercase if possible.  Other elements remain untouched.
+       *
+       *  do_toupper() is a hook for a derived facet to change the behavior of
+       *  uppercasing.  do_toupper() must always return the same result for
+       *  the same input.
+       *
+       *  @param __lo  Pointer to start of range.
+       *  @param __hi  Pointer to end of range.
+       *  @return  @a __hi.
+      */
+      virtual const char_type*
+      do_toupper(char_type* __lo, const char_type* __hi) const;
+
+      /**
+       *  @brief  Convert to lowercase.
+       *
+       *  This virtual function converts the argument to lowercase if
+       *  possible.  If not possible (for example, '2'), returns the argument.
+       *
+       *  do_tolower() is a hook for a derived facet to change the behavior of
+       *  lowercasing.  do_tolower() must always return the same result for
+       *  the same input.
+       *
+       *  @param __c  The wchar_t to convert.
+       *  @return  The lowercase wchar_t if convertible, else @a __c.
+      */
+      virtual char_type
+      do_tolower(char_type __c) const;
+
+      /**
+       *  @brief  Convert array to lowercase.
+       *
+       *  This virtual function converts each wchar_t in the range [lo,hi) to
+       *  lowercase if possible.  Other elements remain untouched.
+       *
+       *  do_tolower() is a hook for a derived facet to change the behavior of
+       *  lowercasing.  do_tolower() must always return the same result for
+       *  the same input.
+       *
+       *  @param __lo  Pointer to start of range.
+       *  @param __hi  Pointer to end of range.
+       *  @return  @a __hi.
+      */
+      virtual const char_type*
+      do_tolower(char_type* __lo, const char_type* __hi) const;
+
+      /**
+       *  @brief  Widen char to wchar_t
+       *
+       *  This virtual function converts the char to wchar_t using the
+       *  simplest reasonable transformation.  For an underived ctype<wchar_t>
+       *  facet, the argument will be cast to wchar_t.
+       *
+       *  do_widen() is a hook for a derived facet to change the behavior of
+       *  widening.  do_widen() must always return the same result for the
+       *  same input.
+       *
+       *  Note: this is not what you want for codepage conversions.  See
+       *  codecvt for that.
+       *
+       *  @param __c  The char to convert.
+       *  @return  The converted wchar_t.
+      */
+      virtual char_type
+      do_widen(char __c) const;
+
+      /**
+       *  @brief  Widen char array to wchar_t array
+       *
+       *  This function converts each char in the input to wchar_t using the
+       *  simplest reasonable transformation.  For an underived ctype<wchar_t>
+       *  facet, the argument will be copied, casting each element to wchar_t.
+       *
+       *  do_widen() is a hook for a derived facet to change the behavior of
+       *  widening.  do_widen() must always return the same result for the
+       *  same input.
+       *
+       *  Note: this is not what you want for codepage conversions.  See
+       *  codecvt for that.
+       *
+       *  @param __lo  Pointer to start range.
+       *  @param __hi  Pointer to end of range.
+       *  @param __to  Pointer to the destination array.
+       *  @return  @a __hi.
+      */
+      virtual const char*
+      do_widen(const char* __lo, const char* __hi, char_type* __to) const;
+
+      /**
+       *  @brief  Narrow wchar_t to char
+       *
+       *  This virtual function converts the argument to char using
+       *  the simplest reasonable transformation.  If the conversion
+       *  fails, dfault is returned instead.  For an underived
+       *  ctype<wchar_t> facet, @a c will be cast to char and
+       *  returned.
+       *
+       *  do_narrow() is a hook for a derived facet to change the
+       *  behavior of narrowing.  do_narrow() must always return the
+       *  same result for the same input.
+       *
+       *  Note: this is not what you want for codepage conversions.  See
+       *  codecvt for that.
+       *
+       *  @param __c  The wchar_t to convert.
+       *  @param __dfault  Char to return if conversion fails.
+       *  @return  The converted char.
+      */
+      virtual char
+      do_narrow(char_type __c, char __dfault) const;
+
+      /**
+       *  @brief  Narrow wchar_t array to char array
+       *
+       *  This virtual function converts each wchar_t in the range [lo,hi) to
+       *  char using the simplest reasonable transformation and writes the
+       *  results to the destination array.  For any wchar_t in the input that
+       *  cannot be converted, @a dfault is used instead.  For an underived
+       *  ctype<wchar_t> facet, the argument will be copied, casting each
+       *  element to char.
+       *
+       *  do_narrow() is a hook for a derived facet to change the behavior of
+       *  narrowing.  do_narrow() must always return the same result for the
+       *  same input.
+       *
+       *  Note: this is not what you want for codepage conversions.  See
+       *  codecvt for that.
+       *
+       *  @param __lo  Pointer to start of range.
+       *  @param __hi  Pointer to end of range.
+       *  @param __dfault  Char to use if conversion fails.
+       *  @param __to  Pointer to the destination array.
+       *  @return  @a __hi.
+      */
+      virtual const char_type*
+      do_narrow(const char_type* __lo, const char_type* __hi,
+		char __dfault, char* __to) const;
+
+      // For use at construction time only.
+      void
+      _M_initialize_ctype() throw();
+    };
+#endif //_GLIBCXX_USE_WCHAR_T
+
+  /// class ctype_byname [22.2.1.2].
+  template<typename _CharT>
+    class ctype_byname : public ctype<_CharT>
+    {
+    public:
+      typedef typename ctype<_CharT>::mask  mask;
+
+      explicit
+      ctype_byname(const char* __s, size_t __refs = 0);
+
+#if __cplusplus >= 201103L
+      explicit
+      ctype_byname(const string& __s, size_t __refs = 0)
+      : ctype_byname(__s.c_str(), __refs) { }
+#endif
+
+    protected:
+      virtual
+      ~ctype_byname() { }
+    };
+
+  /// 22.2.1.4  Class ctype_byname specializations.
+  template<>
+    class ctype_byname<char> : public ctype<char>
+    {
+    public:
+      explicit
+      ctype_byname(const char* __s, size_t __refs = 0);
+
+#if __cplusplus >= 201103L
+      explicit
+      ctype_byname(const string& __s, size_t __refs = 0);
+#endif
+
+    protected:
+      virtual
+      ~ctype_byname();
+    };
+
+#ifdef _GLIBCXX_USE_WCHAR_T
+  template<>
+    class ctype_byname<wchar_t> : public ctype<wchar_t>
+    {
+    public:
+      explicit
+      ctype_byname(const char* __s, size_t __refs = 0);
+
+#if __cplusplus >= 201103L
+      explicit
+      ctype_byname(const string& __s, size_t __refs = 0);
+#endif
+
+    protected:
+      virtual
+      ~ctype_byname();
+    };
+#endif
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+// Include host and configuration specific ctype inlines.
+#include <bits/ctype_inline.h>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  // 22.2.2  The numeric category.
+  class __num_base
+  {
+  public:
+    // NB: Code depends on the order of _S_atoms_out elements.
+    // Below are the indices into _S_atoms_out.
+    enum
+      {
+	_S_ominus,
+	_S_oplus,
+	_S_ox,
+	_S_oX,
+	_S_odigits,
+	_S_odigits_end = _S_odigits + 16,
+	_S_oudigits = _S_odigits_end,
+	_S_oudigits_end = _S_oudigits + 16,
+	_S_oe = _S_odigits + 14,  // For scientific notation, 'e'
+	_S_oE = _S_oudigits + 14, // For scientific notation, 'E'
+	_S_oend = _S_oudigits_end
+      };
+
+    // A list of valid numeric literals for output.  This array
+    // contains chars that will be passed through the current locale's
+    // ctype<_CharT>.widen() and then used to render numbers.
+    // For the standard "C" locale, this is
+    // "-+xX0123456789abcdef0123456789ABCDEF".
+    static const char* _S_atoms_out;
+
+    // String literal of acceptable (narrow) input, for num_get.
+    // "-+xX0123456789abcdefABCDEF"
+    static const char* _S_atoms_in;
+
+    enum
+    {
+      _S_iminus,
+      _S_iplus,
+      _S_ix,
+      _S_iX,
+      _S_izero,
+      _S_ie = _S_izero + 14,
+      _S_iE = _S_izero + 20,
+      _S_iend = 26
+    };
+
+    // num_put
+    // Construct and return valid scanf format for floating point types.
+    static void
+    _S_format_float(const ios_base& __io, char* __fptr, char __mod) throw();
+  };
+
+  template<typename _CharT>
+    struct __numpunct_cache : public locale::facet
+    {
+      const char*			_M_grouping;
+      size_t                            _M_grouping_size;
+      bool				_M_use_grouping;
+      const _CharT*			_M_truename;
+      size_t                            _M_truename_size;
+      const _CharT*			_M_falsename;
+      size_t                            _M_falsename_size;
+      _CharT				_M_decimal_point;
+      _CharT				_M_thousands_sep;
+
+      // A list of valid numeric literals for output: in the standard
+      // "C" locale, this is "-+xX0123456789abcdef0123456789ABCDEF".
+      // This array contains the chars after having been passed
+      // through the current locale's ctype<_CharT>.widen().
+      _CharT				_M_atoms_out[__num_base::_S_oend];
+
+      // A list of valid numeric literals for input: in the standard
+      // "C" locale, this is "-+xX0123456789abcdefABCDEF"
+      // This array contains the chars after having been passed
+      // through the current locale's ctype<_CharT>.widen().
+      _CharT				_M_atoms_in[__num_base::_S_iend];
+
+      bool				_M_allocated;
+
+      __numpunct_cache(size_t __refs = 0)
+      : facet(__refs), _M_grouping(0), _M_grouping_size(0),
+	_M_use_grouping(false),
+	_M_truename(0), _M_truename_size(0), _M_falsename(0),
+	_M_falsename_size(0), _M_decimal_point(_CharT()),
+	_M_thousands_sep(_CharT()), _M_allocated(false)
+	{ }
+
+      ~__numpunct_cache();
+
+      void
+      _M_cache(const locale& __loc);
+
+    private:
+      __numpunct_cache&
+      operator=(const __numpunct_cache&);
+
+      explicit
+      __numpunct_cache(const __numpunct_cache&);
+    };
+
+  template<typename _CharT>
+    __numpunct_cache<_CharT>::~__numpunct_cache()
+    {
+      if (_M_allocated)
+	{
+	  delete [] _M_grouping;
+	  delete [] _M_truename;
+	  delete [] _M_falsename;
+	}
+    }
+
+_GLIBCXX_BEGIN_NAMESPACE_CXX11
+
+  /**
+   *  @brief  Primary class template numpunct.
+   *  @ingroup locales
+   *
+   *  This facet stores several pieces of information related to printing and
+   *  scanning numbers, such as the decimal point character.  It takes a
+   *  template parameter specifying the char type.  The numpunct facet is
+   *  used by streams for many I/O operations involving numbers.
+   *
+   *  The numpunct template uses protected virtual functions to provide the
+   *  actual results.  The public accessors forward the call to the virtual
+   *  functions.  These virtual functions are hooks for developers to
+   *  implement the behavior they require from a numpunct facet.
+  */
+  template<typename _CharT>
+    class numpunct : public locale::facet
+    {
+    public:
+      // Types:
+      ///@{
+      /// Public typedefs
+      typedef _CharT			char_type;
+      typedef basic_string<_CharT>	string_type;
+      ///@}
+      typedef __numpunct_cache<_CharT>  __cache_type;
+
+    protected:
+      __cache_type*			_M_data;
+
+    public:
+      /// Numpunct facet id.
+      static locale::id			id;
+
+      /**
+       *  @brief  Numpunct constructor.
+       *
+       *  @param  __refs  Refcount to pass to the base class.
+       */
+      explicit
+      numpunct(size_t __refs = 0)
+      : facet(__refs), _M_data(0)
+      { _M_initialize_numpunct(); }
+
+      /**
+       *  @brief  Internal constructor.  Not for general use.
+       *
+       *  This is a constructor for use by the library itself to set up the
+       *  predefined locale facets.
+       *
+       *  @param  __cache  __numpunct_cache object.
+       *  @param  __refs  Refcount to pass to the base class.
+       */
+      explicit
+      numpunct(__cache_type* __cache, size_t __refs = 0)
+      : facet(__refs), _M_data(__cache)
+      { _M_initialize_numpunct(); }
+
+      /**
+       *  @brief  Internal constructor.  Not for general use.
+       *
+       *  This is a constructor for use by the library itself to set up new
+       *  locales.
+       *
+       *  @param  __cloc  The C locale.
+       *  @param  __refs  Refcount to pass to the base class.
+       */
+      explicit
+      numpunct(__c_locale __cloc, size_t __refs = 0)
+      : facet(__refs), _M_data(0)
+      { _M_initialize_numpunct(__cloc); }
+
+      /**
+       *  @brief  Return decimal point character.
+       *
+       *  This function returns a char_type to use as a decimal point.  It
+       *  does so by returning returning
+       *  numpunct<char_type>::do_decimal_point().
+       *
+       *  @return  @a char_type representing a decimal point.
+      */
+      char_type
+      decimal_point() const
+      { return this->do_decimal_point(); }
+
+      /**
+       *  @brief  Return thousands separator character.
+       *
+       *  This function returns a char_type to use as a thousands
+       *  separator.  It does so by returning returning
+       *  numpunct<char_type>::do_thousands_sep().
+       *
+       *  @return  char_type representing a thousands separator.
+      */
+      char_type
+      thousands_sep() const
+      { return this->do_thousands_sep(); }
+
+      /**
+       *  @brief  Return grouping specification.
+       *
+       *  This function returns a string representing groupings for the
+       *  integer part of a number.  Groupings indicate where thousands
+       *  separators should be inserted in the integer part of a number.
+       *
+       *  Each char in the return string is interpret as an integer
+       *  rather than a character.  These numbers represent the number
+       *  of digits in a group.  The first char in the string
+       *  represents the number of digits in the least significant
+       *  group.  If a char is negative, it indicates an unlimited
+       *  number of digits for the group.  If more chars from the
+       *  string are required to group a number, the last char is used
+       *  repeatedly.
+       *
+       *  For example, if the grouping() returns "\003\002" and is
+       *  applied to the number 123456789, this corresponds to
+       *  12,34,56,789.  Note that if the string was "32", this would
+       *  put more than 50 digits into the least significant group if
+       *  the character set is ASCII.
+       *
+       *  The string is returned by calling
+       *  numpunct<char_type>::do_grouping().
+       *
+       *  @return  string representing grouping specification.
+      */
+      string
+      grouping() const
+      { return this->do_grouping(); }
+
+      /**
+       *  @brief  Return string representation of bool true.
+       *
+       *  This function returns a string_type containing the text
+       *  representation for true bool variables.  It does so by calling
+       *  numpunct<char_type>::do_truename().
+       *
+       *  @return  string_type representing printed form of true.
+      */
+      string_type
+      truename() const
+      { return this->do_truename(); }
+
+      /**
+       *  @brief  Return string representation of bool false.
+       *
+       *  This function returns a string_type containing the text
+       *  representation for false bool variables.  It does so by calling
+       *  numpunct<char_type>::do_falsename().
+       *
+       *  @return  string_type representing printed form of false.
+      */
+      string_type
+      falsename() const
+      { return this->do_falsename(); }
+
+    protected:
+      /// Destructor.
+      virtual
+      ~numpunct();
+
+      /**
+       *  @brief  Return decimal point character.
+       *
+       *  Returns a char_type to use as a decimal point.  This function is a
+       *  hook for derived classes to change the value returned.
+       *
+       *  @return  @a char_type representing a decimal point.
+      */
+      virtual char_type
+      do_decimal_point() const
+      { return _M_data->_M_decimal_point; }
+
+      /**
+       *  @brief  Return thousands separator character.
+       *
+       *  Returns a char_type to use as a thousands separator.  This function
+       *  is a hook for derived classes to change the value returned.
+       *
+       *  @return  @a char_type representing a thousands separator.
+      */
+      virtual char_type
+      do_thousands_sep() const
+      { return _M_data->_M_thousands_sep; }
+
+      /**
+       *  @brief  Return grouping specification.
+       *
+       *  Returns a string representing groupings for the integer part of a
+       *  number.  This function is a hook for derived classes to change the
+       *  value returned.  @see grouping() for details.
+       *
+       *  @return  String representing grouping specification.
+      */
+      virtual string
+      do_grouping() const
+      { return _M_data->_M_grouping; }
+
+      /**
+       *  @brief  Return string representation of bool true.
+       *
+       *  Returns a string_type containing the text representation for true
+       *  bool variables.  This function is a hook for derived classes to
+       *  change the value returned.
+       *
+       *  @return  string_type representing printed form of true.
+      */
+      virtual string_type
+      do_truename() const
+      { return _M_data->_M_truename; }
+
+      /**
+       *  @brief  Return string representation of bool false.
+       *
+       *  Returns a string_type containing the text representation for false
+       *  bool variables.  This function is a hook for derived classes to
+       *  change the value returned.
+       *
+       *  @return  string_type representing printed form of false.
+      */
+      virtual string_type
+      do_falsename() const
+      { return _M_data->_M_falsename; }
+
+      // For use at construction time only.
+      void
+      _M_initialize_numpunct(__c_locale __cloc = 0);
+    };
+
+  template<typename _CharT>
+    locale::id numpunct<_CharT>::id;
+
+  template<>
+    numpunct<char>::~numpunct();
+
+  template<>
+    void
+    numpunct<char>::_M_initialize_numpunct(__c_locale __cloc);
+
+#ifdef _GLIBCXX_USE_WCHAR_T
+  template<>
+    numpunct<wchar_t>::~numpunct();
+
+  template<>
+    void
+    numpunct<wchar_t>::_M_initialize_numpunct(__c_locale __cloc);
+#endif
+
+  /// class numpunct_byname [22.2.3.2].
+  template<typename _CharT>
+    class numpunct_byname : public numpunct<_CharT>
+    {
+    public:
+      typedef _CharT			char_type;
+      typedef basic_string<_CharT>	string_type;
+
+      explicit
+      numpunct_byname(const char* __s, size_t __refs = 0)
+      : numpunct<_CharT>(__refs)
+      {
+	if (__builtin_strcmp(__s, "C") != 0
+	    && __builtin_strcmp(__s, "POSIX") != 0)
+	  {
+	    __c_locale __tmp;
+	    this->_S_create_c_locale(__tmp, __s);
+	    this->_M_initialize_numpunct(__tmp);
+	    this->_S_destroy_c_locale(__tmp);
+	  }
+      }
+
+#if __cplusplus >= 201103L
+      explicit
+      numpunct_byname(const string& __s, size_t __refs = 0)
+      : numpunct_byname(__s.c_str(), __refs) { }
+#endif
+
+    protected:
+      virtual
+      ~numpunct_byname() { }
+    };
+
+_GLIBCXX_END_NAMESPACE_CXX11
+
+_GLIBCXX_BEGIN_NAMESPACE_LDBL
+
+  /**
+   *  @brief  Primary class template num_get.
+   *  @ingroup locales
+   *
+   *  This facet encapsulates the code to parse and return a number
+   *  from a string.  It is used by the istream numeric extraction
+   *  operators.
+   *
+   *  The num_get template uses protected virtual functions to provide the
+   *  actual results.  The public accessors forward the call to the virtual
+   *  functions.  These virtual functions are hooks for developers to
+   *  implement the behavior they require from the num_get facet.
+  */
+  template<typename _CharT, typename _InIter>
+    class num_get : public locale::facet
+    {
+    public:
+      // Types:
+      ///@{
+      /// Public typedefs
+      typedef _CharT			char_type;
+      typedef _InIter			iter_type;
+      ///@}
+
+      /// Numpunct facet id.
+      static locale::id			id;
+
+      /**
+       *  @brief  Constructor performs initialization.
+       *
+       *  This is the constructor provided by the standard.
+       *
+       *  @param __refs  Passed to the base facet class.
+      */
+      explicit
+      num_get(size_t __refs = 0) : facet(__refs) { }
+
+      /**
+       *  @brief  Numeric parsing.
+       *
+       *  Parses the input stream into the bool @a v.  It does so by calling
+       *  num_get::do_get().
+       *
+       *  If ios_base::boolalpha is set, attempts to read
+       *  ctype<CharT>::truename() or ctype<CharT>::falsename().  Sets
+       *  @a v to true or false if successful.  Sets err to
+       *  ios_base::failbit if reading the string fails.  Sets err to
+       *  ios_base::eofbit if the stream is emptied.
+       *
+       *  If ios_base::boolalpha is not set, proceeds as with reading a long,
+       *  except if the value is 1, sets @a v to true, if the value is 0, sets
+       *  @a v to false, and otherwise set err to ios_base::failbit.
+       *
+       *  @param  __in  Start of input stream.
+       *  @param  __end  End of input stream.
+       *  @param  __io  Source of locale and flags.
+       *  @param  __err  Error flags to set.
+       *  @param  __v  Value to format and insert.
+       *  @return  Iterator after reading.
+      */
+      iter_type
+      get(iter_type __in, iter_type __end, ios_base& __io,
+	  ios_base::iostate& __err, bool& __v) const
+      { return this->do_get(__in, __end, __io, __err, __v); }
+
+      ///@{
+      /**
+       *  @brief  Numeric parsing.
+       *
+       *  Parses the input stream into the integral variable @a v.  It does so
+       *  by calling num_get::do_get().
+       *
+       *  Parsing is affected by the flag settings in @a io.
+       *
+       *  The basic parse is affected by the value of io.flags() &
+       *  ios_base::basefield.  If equal to ios_base::oct, parses like the
+       *  scanf %o specifier.  Else if equal to ios_base::hex, parses like %X
+       *  specifier.  Else if basefield equal to 0, parses like the %i
+       *  specifier.  Otherwise, parses like %d for signed and %u for unsigned
+       *  types.  The matching type length modifier is also used.
+       *
+       *  Digit grouping is interpreted according to
+       *  numpunct::grouping() and numpunct::thousands_sep().  If the
+       *  pattern of digit groups isn't consistent, sets err to
+       *  ios_base::failbit.
+       *
+       *  If parsing the string yields a valid value for @a v, @a v is set.
+       *  Otherwise, sets err to ios_base::failbit and leaves @a v unaltered.
+       *  Sets err to ios_base::eofbit if the stream is emptied.
+       *
+       *  @param  __in  Start of input stream.
+       *  @param  __end  End of input stream.
+       *  @param  __io  Source of locale and flags.
+       *  @param  __err  Error flags to set.
+       *  @param  __v  Value to format and insert.
+       *  @return  Iterator after reading.
+      */
+      iter_type
+      get(iter_type __in, iter_type __end, ios_base& __io,
+	  ios_base::iostate& __err, long& __v) const
+      { return this->do_get(__in, __end, __io, __err, __v); }
+
+      iter_type
+      get(iter_type __in, iter_type __end, ios_base& __io,
+	  ios_base::iostate& __err, unsigned short& __v) const
+      { return this->do_get(__in, __end, __io, __err, __v); }
+
+      iter_type
+      get(iter_type __in, iter_type __end, ios_base& __io,
+	  ios_base::iostate& __err, unsigned int& __v)   const
+      { return this->do_get(__in, __end, __io, __err, __v); }
+
+      iter_type
+      get(iter_type __in, iter_type __end, ios_base& __io,
+	  ios_base::iostate& __err, unsigned long& __v)  const
+      { return this->do_get(__in, __end, __io, __err, __v); }
+
+#ifdef _GLIBCXX_USE_LONG_LONG
+      iter_type
+      get(iter_type __in, iter_type __end, ios_base& __io,
+	  ios_base::iostate& __err, long long& __v) const
+      { return this->do_get(__in, __end, __io, __err, __v); }
+
+      iter_type
+      get(iter_type __in, iter_type __end, ios_base& __io,
+	  ios_base::iostate& __err, unsigned long long& __v)  const
+      { return this->do_get(__in, __end, __io, __err, __v); }
+#endif
+      ///@}
+
+      ///@{
+      /**
+       *  @brief  Numeric parsing.
+       *
+       *  Parses the input stream into the integral variable @a v.  It does so
+       *  by calling num_get::do_get().
+       *
+       *  The input characters are parsed like the scanf %g specifier.  The
+       *  matching type length modifier is also used.
+       *
+       *  The decimal point character used is numpunct::decimal_point().
+       *  Digit grouping is interpreted according to
+       *  numpunct::grouping() and numpunct::thousands_sep().  If the
+       *  pattern of digit groups isn't consistent, sets err to
+       *  ios_base::failbit.
+       *
+       *  If parsing the string yields a valid value for @a v, @a v is set.
+       *  Otherwise, sets err to ios_base::failbit and leaves @a v unaltered.
+       *  Sets err to ios_base::eofbit if the stream is emptied.
+       *
+       *  @param  __in  Start of input stream.
+       *  @param  __end  End of input stream.
+       *  @param  __io  Source of locale and flags.
+       *  @param  __err  Error flags to set.
+       *  @param  __v  Value to format and insert.
+       *  @return  Iterator after reading.
+      */
+      iter_type
+      get(iter_type __in, iter_type __end, ios_base& __io,
+	  ios_base::iostate& __err, float& __v) const
+      { return this->do_get(__in, __end, __io, __err, __v); }
+
+      iter_type
+      get(iter_type __in, iter_type __end, ios_base& __io,
+	  ios_base::iostate& __err, double& __v) const
+      { return this->do_get(__in, __end, __io, __err, __v); }
+
+      iter_type
+      get(iter_type __in, iter_type __end, ios_base& __io,
+	  ios_base::iostate& __err, long double& __v) const
+      { return this->do_get(__in, __end, __io, __err, __v); }
+      ///@}
+
+      /**
+       *  @brief  Numeric parsing.
+       *
+       *  Parses the input stream into the pointer variable @a v.  It does so
+       *  by calling num_get::do_get().
+       *
+       *  The input characters are parsed like the scanf %p specifier.
+       *
+       *  Digit grouping is interpreted according to
+       *  numpunct::grouping() and numpunct::thousands_sep().  If the
+       *  pattern of digit groups isn't consistent, sets err to
+       *  ios_base::failbit.
+       *
+       *  Note that the digit grouping effect for pointers is a bit ambiguous
+       *  in the standard and shouldn't be relied on.  See DR 344.
+       *
+       *  If parsing the string yields a valid value for @a v, @a v is set.
+       *  Otherwise, sets err to ios_base::failbit and leaves @a v unaltered.
+       *  Sets err to ios_base::eofbit if the stream is emptied.
+       *
+       *  @param  __in  Start of input stream.
+       *  @param  __end  End of input stream.
+       *  @param  __io  Source of locale and flags.
+       *  @param  __err  Error flags to set.
+       *  @param  __v  Value to format and insert.
+       *  @return  Iterator after reading.
+      */
+      iter_type
+      get(iter_type __in, iter_type __end, ios_base& __io,
+	  ios_base::iostate& __err, void*& __v) const
+      { return this->do_get(__in, __end, __io, __err, __v); }
+
+    protected:
+      /// Destructor.
+      virtual ~num_get() { }
+
+      _GLIBCXX_DEFAULT_ABI_TAG
+      iter_type
+      _M_extract_float(iter_type, iter_type, ios_base&, ios_base::iostate&,
+		       string&) const;
+
+      template<typename _ValueT>
+	_GLIBCXX_DEFAULT_ABI_TAG
+	iter_type
+	_M_extract_int(iter_type, iter_type, ios_base&, ios_base::iostate&,
+		       _ValueT&) const;
+
+      template<typename _CharT2>
+      typename __gnu_cxx::__enable_if<__is_char<_CharT2>::__value, int>::__type
+	_M_find(const _CharT2*, size_t __len, _CharT2 __c) const
+	{
+	  int __ret = -1;
+	  if (__len <= 10)
+	    {
+	      if (__c >= _CharT2('0') && __c < _CharT2(_CharT2('0') + __len))
+		__ret = __c - _CharT2('0');
+	    }
+	  else
+	    {
+	      if (__c >= _CharT2('0') && __c <= _CharT2('9'))
+		__ret = __c - _CharT2('0');
+	      else if (__c >= _CharT2('a') && __c <= _CharT2('f'))
+		__ret = 10 + (__c - _CharT2('a'));
+	      else if (__c >= _CharT2('A') && __c <= _CharT2('F'))
+		__ret = 10 + (__c - _CharT2('A'));
+	    }
+	  return __ret;
+	}
+
+      template<typename _CharT2>
+      typename __gnu_cxx::__enable_if<!__is_char<_CharT2>::__value,
+				      int>::__type
+	_M_find(const _CharT2* __zero, size_t __len, _CharT2 __c) const
+	{
+	  int __ret = -1;
+	  const char_type* __q = char_traits<_CharT2>::find(__zero, __len, __c);
+	  if (__q)
+	    {
+	      __ret = __q - __zero;
+	      if (__ret > 15)
+		__ret -= 6;
+	    }
+	  return __ret;
+	}
+
+      ///@{
+      /**
+       *  @brief  Numeric parsing.
+       *
+       *  Parses the input stream into the variable @a v.  This function is a
+       *  hook for derived classes to change the value returned.  @see get()
+       *  for more details.
+       *
+       *  @param  __beg  Start of input stream.
+       *  @param  __end  End of input stream.
+       *  @param  __io  Source of locale and flags.
+       *  @param  __err  Error flags to set.
+       *  @param  __v  Value to format and insert.
+       *  @return  Iterator after reading.
+      */
+      virtual iter_type
+      do_get(iter_type, iter_type, ios_base&, ios_base::iostate&, bool&) const;
+
+      virtual iter_type
+      do_get(iter_type __beg, iter_type __end, ios_base& __io,
+	     ios_base::iostate& __err, long& __v) const
+      { return _M_extract_int(__beg, __end, __io, __err, __v); }
+
+      virtual iter_type
+      do_get(iter_type __beg, iter_type __end, ios_base& __io,
+	     ios_base::iostate& __err, unsigned short& __v) const
+      { return _M_extract_int(__beg, __end, __io, __err, __v); }
+
+      virtual iter_type
+      do_get(iter_type __beg, iter_type __end, ios_base& __io,
+	     ios_base::iostate& __err, unsigned int& __v) const
+      { return _M_extract_int(__beg, __end, __io, __err, __v); }
+
+      virtual iter_type
+      do_get(iter_type __beg, iter_type __end, ios_base& __io,
+	     ios_base::iostate& __err, unsigned long& __v) const
+      { return _M_extract_int(__beg, __end, __io, __err, __v); }
+
+#ifdef _GLIBCXX_USE_LONG_LONG
+      virtual iter_type
+      do_get(iter_type __beg, iter_type __end, ios_base& __io,
+	     ios_base::iostate& __err, long long& __v) const
+      { return _M_extract_int(__beg, __end, __io, __err, __v); }
+
+      virtual iter_type
+      do_get(iter_type __beg, iter_type __end, ios_base& __io,
+	     ios_base::iostate& __err, unsigned long long& __v) const
+      { return _M_extract_int(__beg, __end, __io, __err, __v); }
+#endif
+
+      virtual iter_type
+      do_get(iter_type, iter_type, ios_base&, ios_base::iostate&, float&) const;
+
+      virtual iter_type
+      do_get(iter_type, iter_type, ios_base&, ios_base::iostate&,
+	     double&) const;
+
+      // XXX GLIBCXX_ABI Deprecated
+#if defined _GLIBCXX_LONG_DOUBLE_COMPAT && defined __LONG_DOUBLE_128__
+      // For __gnu_cxx_ldbl128::num_get and __gnu_cxx_ieee128::num_get
+      // this entry in the vtable is for a 64-bit "long double" with the
+      // same format as double. This keeps the vtable layout consistent
+      // with std::num_get (visible when -mlong-double-64 is used).
+      virtual iter_type
+      __do_get(iter_type, iter_type, ios_base&, ios_base::iostate&,
+	       double&) const;
+#else
+      virtual iter_type
+      do_get(iter_type, iter_type, ios_base&, ios_base::iostate&,
+	     long double&) const;
+#endif
+
+      virtual iter_type
+      do_get(iter_type, iter_type, ios_base&, ios_base::iostate&, void*&) const;
+
+      // XXX GLIBCXX_ABI Deprecated
+#if defined _GLIBCXX_LONG_DOUBLE_ALT128_COMPAT \
+      && defined __LONG_DOUBLE_IEEE128__
+      // For __gnu_cxx_ieee128::num_get this entry in the vtable is for
+      // the non-IEEE 128-bit "long double" (aka "double double"). This
+      // is consistent with __gnu_cxx_ldbl128::num_get (-mabi=ibmlongdouble)
+      virtual iter_type
+      __do_get(iter_type, iter_type, ios_base&, ios_base::iostate&,
+	       __ibm128&) const;
+#endif
+
+      // XXX GLIBCXX_ABI Deprecated
+#if defined _GLIBCXX_LONG_DOUBLE_COMPAT && defined __LONG_DOUBLE_128__
+      // For __gnu_cxx_ldbl128::num_get and __gnu_cxx_ieee128::num_get
+      // this entry in the vtable is for the 128-bit "long double" type.
+      virtual iter_type
+      do_get(iter_type, iter_type, ios_base&, ios_base::iostate&,
+	     long double&) const;
+#endif
+      ///@}
+    };
+
+  template<typename _CharT, typename _InIter>
+    locale::id num_get<_CharT, _InIter>::id;
+
+
+  /**
+   *  @brief  Primary class template num_put.
+   *  @ingroup locales
+   *
+   *  This facet encapsulates the code to convert a number to a string.  It is
+   *  used by the ostream numeric insertion operators.
+   *
+   *  The num_put template uses protected virtual functions to provide the
+   *  actual results.  The public accessors forward the call to the virtual
+   *  functions.  These virtual functions are hooks for developers to
+   *  implement the behavior they require from the num_put facet.
+  */
+  template<typename _CharT, typename _OutIter>
+    class num_put : public locale::facet
+    {
+    public:
+      // Types:
+      ///@{
+      /// Public typedefs
+      typedef _CharT		char_type;
+      typedef _OutIter		iter_type;
+      ///@}
+
+      /// Numpunct facet id.
+      static locale::id		id;
+
+      /**
+       *  @brief  Constructor performs initialization.
+       *
+       *  This is the constructor provided by the standard.
+       *
+       *  @param __refs  Passed to the base facet class.
+      */
+      explicit
+      num_put(size_t __refs = 0) : facet(__refs) { }
+
+      /**
+       *  @brief  Numeric formatting.
+       *
+       *  Formats the boolean @a v and inserts it into a stream.  It does so
+       *  by calling num_put::do_put().
+       *
+       *  If ios_base::boolalpha is set, writes ctype<CharT>::truename() or
+       *  ctype<CharT>::falsename().  Otherwise formats @a v as an int.
+       *
+       *  @param  __s  Stream to write to.
+       *  @param  __io  Source of locale and flags.
+       *  @param  __fill  Char_type to use for filling.
+       *  @param  __v  Value to format and insert.
+       *  @return  Iterator after writing.
+      */
+      iter_type
+      put(iter_type __s, ios_base& __io, char_type __fill, bool __v) const
+      { return this->do_put(__s, __io, __fill, __v); }
+
+      ///@{
+      /**
+       *  @brief  Numeric formatting.
+       *
+       *  Formats the integral value @a v and inserts it into a
+       *  stream.  It does so by calling num_put::do_put().
+       *
+       *  Formatting is affected by the flag settings in @a io.
+       *
+       *  The basic format is affected by the value of io.flags() &
+       *  ios_base::basefield.  If equal to ios_base::oct, formats like the
+       *  printf %o specifier.  Else if equal to ios_base::hex, formats like
+       *  %x or %X with ios_base::uppercase unset or set respectively.
+       *  Otherwise, formats like %d, %ld, %lld for signed and %u, %lu, %llu
+       *  for unsigned values.  Note that if both oct and hex are set, neither
+       *  will take effect.
+       *
+       *  If ios_base::showpos is set, '+' is output before positive values.
+       *  If ios_base::showbase is set, '0' precedes octal values (except 0)
+       *  and '0[xX]' precedes hex values.
+       *
+       *  The decimal point character used is numpunct::decimal_point().
+       *  Thousands separators are inserted according to
+       *  numpunct::grouping() and numpunct::thousands_sep().
+       *
+       *  If io.width() is non-zero, enough @a fill characters are inserted to
+       *  make the result at least that wide.  If
+       *  (io.flags() & ios_base::adjustfield) == ios_base::left, result is
+       *  padded at the end.  If ios_base::internal, then padding occurs
+       *  immediately after either a '+' or '-' or after '0x' or '0X'.
+       *  Otherwise, padding occurs at the beginning.
+       *
+       *  @param  __s  Stream to write to.
+       *  @param  __io  Source of locale and flags.
+       *  @param  __fill  Char_type to use for filling.
+       *  @param  __v  Value to format and insert.
+       *  @return  Iterator after writing.
+      */
+      iter_type
+      put(iter_type __s, ios_base& __io, char_type __fill, long __v) const
+      { return this->do_put(__s, __io, __fill, __v); }
+
+      iter_type
+      put(iter_type __s, ios_base& __io, char_type __fill,
+	  unsigned long __v) const
+      { return this->do_put(__s, __io, __fill, __v); }
+
+#ifdef _GLIBCXX_USE_LONG_LONG
+      iter_type
+      put(iter_type __s, ios_base& __io, char_type __fill, long long __v) const
+      { return this->do_put(__s, __io, __fill, __v); }
+
+      iter_type
+      put(iter_type __s, ios_base& __io, char_type __fill,
+	  unsigned long long __v) const
+      { return this->do_put(__s, __io, __fill, __v); }
+#endif
+      ///@}
+
+      ///@{
+      /**
+       *  @brief  Numeric formatting.
+       *
+       *  Formats the floating point value @a v and inserts it into a stream.
+       *  It does so by calling num_put::do_put().
+       *
+       *  Formatting is affected by the flag settings in @a io.
+       *
+       *  The basic format is affected by the value of io.flags() &
+       *  ios_base::floatfield.  If equal to ios_base::fixed, formats like the
+       *  printf %f specifier.  Else if equal to ios_base::scientific, formats
+       *  like %e or %E with ios_base::uppercase unset or set respectively.
+       *  Otherwise, formats like %g or %G depending on uppercase.  Note that
+       *  if both fixed and scientific are set, the effect will also be like
+       *  %g or %G.
+       *
+       *  The output precision is given by io.precision().  This precision is
+       *  capped at numeric_limits::digits10 + 2 (different for double and
+       *  long double).  The default precision is 6.
+       *
+       *  If ios_base::showpos is set, '+' is output before positive values.
+       *  If ios_base::showpoint is set, a decimal point will always be
+       *  output.
+       *
+       *  The decimal point character used is numpunct::decimal_point().
+       *  Thousands separators are inserted according to
+       *  numpunct::grouping() and numpunct::thousands_sep().
+       *
+       *  If io.width() is non-zero, enough @a fill characters are inserted to
+       *  make the result at least that wide.  If
+       *  (io.flags() & ios_base::adjustfield) == ios_base::left, result is
+       *  padded at the end.  If ios_base::internal, then padding occurs
+       *  immediately after either a '+' or '-' or after '0x' or '0X'.
+       *  Otherwise, padding occurs at the beginning.
+       *
+       *  @param  __s  Stream to write to.
+       *  @param  __io  Source of locale and flags.
+       *  @param  __fill  Char_type to use for filling.
+       *  @param  __v  Value to format and insert.
+       *  @return  Iterator after writing.
+      */
+      iter_type
+      put(iter_type __s, ios_base& __io, char_type __fill, double __v) const
+      { return this->do_put(__s, __io, __fill, __v); }
+
+      iter_type
+      put(iter_type __s, ios_base& __io, char_type __fill,
+	  long double __v) const
+      { return this->do_put(__s, __io, __fill, __v); }
+      ///@}
+
+      /**
+       *  @brief  Numeric formatting.
+       *
+       *  Formats the pointer value @a v and inserts it into a stream.  It
+       *  does so by calling num_put::do_put().
+       *
+       *  This function formats @a v as an unsigned long with ios_base::hex
+       *  and ios_base::showbase set.
+       *
+       *  @param  __s  Stream to write to.
+       *  @param  __io  Source of locale and flags.
+       *  @param  __fill  Char_type to use for filling.
+       *  @param  __v  Value to format and insert.
+       *  @return  Iterator after writing.
+      */
+      iter_type
+      put(iter_type __s, ios_base& __io, char_type __fill,
+	  const void* __v) const
+      { return this->do_put(__s, __io, __fill, __v); }
+
+    protected:
+      template<typename _ValueT>
+	iter_type
+	_M_insert_float(iter_type, ios_base& __io, char_type __fill,
+			char __mod, _ValueT __v) const;
+
+      void
+      _M_group_float(const char* __grouping, size_t __grouping_size,
+		     char_type __sep, const char_type* __p, char_type* __new,
+		     char_type* __cs, int& __len) const;
+
+      template<typename _ValueT>
+	iter_type
+	_M_insert_int(iter_type, ios_base& __io, char_type __fill,
+		      _ValueT __v) const;
+
+      void
+      _M_group_int(const char* __grouping, size_t __grouping_size,
+		   char_type __sep, ios_base& __io, char_type* __new,
+		   char_type* __cs, int& __len) const;
+
+      void
+      _M_pad(char_type __fill, streamsize __w, ios_base& __io,
+	     char_type* __new, const char_type* __cs, int& __len) const;
+
+      /// Destructor.
+      virtual
+      ~num_put() { }
+
+      ///@{
+      /**
+       *  @brief  Numeric formatting.
+       *
+       *  These functions do the work of formatting numeric values and
+       *  inserting them into a stream. This function is a hook for derived
+       *  classes to change the value returned.
+       *
+       *  @param  __s  Stream to write to.
+       *  @param  __io  Source of locale and flags.
+       *  @param  __fill  Char_type to use for filling.
+       *  @param  __v  Value to format and insert.
+       *  @return  Iterator after writing.
+      */
+      virtual iter_type
+      do_put(iter_type __s, ios_base& __io, char_type __fill, bool __v) const;
+
+      virtual iter_type
+      do_put(iter_type __s, ios_base& __io, char_type __fill, long __v) const
+      { return _M_insert_int(__s, __io, __fill, __v); }
+
+      virtual iter_type
+      do_put(iter_type __s, ios_base& __io, char_type __fill,
+	     unsigned long __v) const
+      { return _M_insert_int(__s, __io, __fill, __v); }
+
+#ifdef _GLIBCXX_USE_LONG_LONG
+      virtual iter_type
+      do_put(iter_type __s, ios_base& __io, char_type __fill,
+	     long long __v) const
+      { return _M_insert_int(__s, __io, __fill, __v); }
+
+      virtual iter_type
+      do_put(iter_type __s, ios_base& __io, char_type __fill,
+	     unsigned long long __v) const
+      { return _M_insert_int(__s, __io, __fill, __v); }
+#endif
+
+      virtual iter_type
+      do_put(iter_type, ios_base&, char_type, double) const;
+
+      // XXX GLIBCXX_ABI Deprecated
+#if defined _GLIBCXX_LONG_DOUBLE_COMPAT && defined __LONG_DOUBLE_128__
+      virtual iter_type
+      __do_put(iter_type, ios_base&, char_type, double) const;
+#else
+      virtual iter_type
+      do_put(iter_type, ios_base&, char_type, long double) const;
+#endif
+
+      virtual iter_type
+      do_put(iter_type, ios_base&, char_type, const void*) const;
+
+      // XXX GLIBCXX_ABI Deprecated
+#if defined _GLIBCXX_LONG_DOUBLE_ALT128_COMPAT \
+      && defined __LONG_DOUBLE_IEEE128__
+      virtual iter_type
+      __do_put(iter_type, ios_base&, char_type, __ibm128) const;
+#endif
+
+      // XXX GLIBCXX_ABI Deprecated
+#if defined _GLIBCXX_LONG_DOUBLE_COMPAT && defined __LONG_DOUBLE_128__
+      virtual iter_type
+      do_put(iter_type, ios_base&, char_type, long double) const;
+#endif
+      ///@}
+    };
+
+  template <typename _CharT, typename _OutIter>
+    locale::id num_put<_CharT, _OutIter>::id;
+
+_GLIBCXX_END_NAMESPACE_LDBL
+
+  // Subclause convenience interfaces, inlines.
+  // NB: These are inline because, when used in a loop, some compilers
+  // can hoist the body out of the loop; then it's just as fast as the
+  // C is*() function.
+
+  /// Convenience interface to ctype.is(ctype_base::space, __c).
+  template<typename _CharT>
+    inline bool
+    isspace(_CharT __c, const locale& __loc)
+    { return use_facet<ctype<_CharT> >(__loc).is(ctype_base::space, __c); }
+
+  /// Convenience interface to ctype.is(ctype_base::print, __c).
+  template<typename _CharT>
+    inline bool
+    isprint(_CharT __c, const locale& __loc)
+    { return use_facet<ctype<_CharT> >(__loc).is(ctype_base::print, __c); }
+
+  /// Convenience interface to ctype.is(ctype_base::cntrl, __c).
+  template<typename _CharT>
+    inline bool
+    iscntrl(_CharT __c, const locale& __loc)
+    { return use_facet<ctype<_CharT> >(__loc).is(ctype_base::cntrl, __c); }
+
+  /// Convenience interface to ctype.is(ctype_base::upper, __c).
+  template<typename _CharT>
+    inline bool
+    isupper(_CharT __c, const locale& __loc)
+    { return use_facet<ctype<_CharT> >(__loc).is(ctype_base::upper, __c); }
+
+  /// Convenience interface to ctype.is(ctype_base::lower, __c).
+  template<typename _CharT>
+    inline bool
+    islower(_CharT __c, const locale& __loc)
+    { return use_facet<ctype<_CharT> >(__loc).is(ctype_base::lower, __c); }
+
+  /// Convenience interface to ctype.is(ctype_base::alpha, __c).
+  template<typename _CharT>
+    inline bool
+    isalpha(_CharT __c, const locale& __loc)
+    { return use_facet<ctype<_CharT> >(__loc).is(ctype_base::alpha, __c); }
+
+  /// Convenience interface to ctype.is(ctype_base::digit, __c).
+  template<typename _CharT>
+    inline bool
+    isdigit(_CharT __c, const locale& __loc)
+    { return use_facet<ctype<_CharT> >(__loc).is(ctype_base::digit, __c); }
+
+  /// Convenience interface to ctype.is(ctype_base::punct, __c).
+  template<typename _CharT>
+    inline bool
+    ispunct(_CharT __c, const locale& __loc)
+    { return use_facet<ctype<_CharT> >(__loc).is(ctype_base::punct, __c); }
+
+  /// Convenience interface to ctype.is(ctype_base::xdigit, __c).
+  template<typename _CharT>
+    inline bool
+    isxdigit(_CharT __c, const locale& __loc)
+    { return use_facet<ctype<_CharT> >(__loc).is(ctype_base::xdigit, __c); }
+
+  /// Convenience interface to ctype.is(ctype_base::alnum, __c).
+  template<typename _CharT>
+    inline bool
+    isalnum(_CharT __c, const locale& __loc)
+    { return use_facet<ctype<_CharT> >(__loc).is(ctype_base::alnum, __c); }
+
+  /// Convenience interface to ctype.is(ctype_base::graph, __c).
+  template<typename _CharT>
+    inline bool
+    isgraph(_CharT __c, const locale& __loc)
+    { return use_facet<ctype<_CharT> >(__loc).is(ctype_base::graph, __c); }
+
+#if __cplusplus >= 201103L
+  /// Convenience interface to ctype.is(ctype_base::blank, __c).
+  template<typename _CharT>
+    inline bool
+    isblank(_CharT __c, const locale& __loc)
+    { return use_facet<ctype<_CharT> >(__loc).is(ctype_base::blank, __c); }
+#endif
+
+  /// Convenience interface to ctype.toupper(__c).
+  template<typename _CharT>
+    inline _CharT
+    toupper(_CharT __c, const locale& __loc)
+    { return use_facet<ctype<_CharT> >(__loc).toupper(__c); }
+
+  /// Convenience interface to ctype.tolower(__c).
+  template<typename _CharT>
+    inline _CharT
+    tolower(_CharT __c, const locale& __loc)
+    { return use_facet<ctype<_CharT> >(__loc).tolower(__c); }
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+# include <bits/locale_facets.tcc>
+
+#endif
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@@ -0,0 +1,1404 @@
+// Locale support -*- C++ -*-
+
+// Copyright (C) 1997-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/locale_facets.tcc
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{locale}
+ */
+
+#ifndef _LOCALE_FACETS_TCC
+#define _LOCALE_FACETS_TCC 1
+
+#pragma GCC system_header
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  // Routine to access a cache for the facet.  If the cache didn't
+  // exist before, it gets constructed on the fly.
+  template<typename _Facet>
+    struct __use_cache
+    {
+      const _Facet*
+      operator() (const locale& __loc) const;
+    };
+
+  // Specializations.
+  template<typename _CharT>
+    struct __use_cache<__numpunct_cache<_CharT> >
+    {
+      const __numpunct_cache<_CharT>*
+      operator() (const locale& __loc) const
+      {
+	const size_t __i = numpunct<_CharT>::id._M_id();
+	const locale::facet** __caches = __loc._M_impl->_M_caches;
+	if (!__caches[__i])
+	  {
+	    __numpunct_cache<_CharT>* __tmp = 0;
+	    __try
+	      {
+		__tmp = new __numpunct_cache<_CharT>;
+		__tmp->_M_cache(__loc);
+	      }
+	    __catch(...)
+	      {
+		delete __tmp;
+		__throw_exception_again;
+	      }
+	    __loc._M_impl->_M_install_cache(__tmp, __i);
+	  }
+	return static_cast<const __numpunct_cache<_CharT>*>(__caches[__i]);
+      }
+    };
+
+  template<typename _CharT>
+    void
+    __numpunct_cache<_CharT>::_M_cache(const locale& __loc)
+    {
+      const numpunct<_CharT>& __np = use_facet<numpunct<_CharT> >(__loc);
+
+      char* __grouping = 0;
+      _CharT* __truename = 0;
+      _CharT* __falsename = 0;
+      __try
+	{
+	  const string& __g = __np.grouping();
+	  _M_grouping_size = __g.size();
+	  __grouping = new char[_M_grouping_size];
+	  __g.copy(__grouping, _M_grouping_size);
+	  _M_use_grouping = (_M_grouping_size
+			     && static_cast<signed char>(__grouping[0]) > 0
+			     && (__grouping[0]
+				 != __gnu_cxx::__numeric_traits<char>::__max));
+
+	  const basic_string<_CharT>& __tn = __np.truename();
+	  _M_truename_size = __tn.size();
+	  __truename = new _CharT[_M_truename_size];
+	  __tn.copy(__truename, _M_truename_size);
+
+	  const basic_string<_CharT>& __fn = __np.falsename();
+	  _M_falsename_size = __fn.size();
+	  __falsename = new _CharT[_M_falsename_size];
+	  __fn.copy(__falsename, _M_falsename_size);
+
+	  _M_decimal_point = __np.decimal_point();
+	  _M_thousands_sep = __np.thousands_sep();
+
+	  const ctype<_CharT>& __ct = use_facet<ctype<_CharT> >(__loc);
+	  __ct.widen(__num_base::_S_atoms_out,
+		     __num_base::_S_atoms_out
+		     + __num_base::_S_oend, _M_atoms_out);
+	  __ct.widen(__num_base::_S_atoms_in,
+		     __num_base::_S_atoms_in
+		     + __num_base::_S_iend, _M_atoms_in);
+
+	  _M_grouping = __grouping;
+	  _M_truename = __truename;
+	  _M_falsename = __falsename;
+	  _M_allocated = true;
+	}
+      __catch(...)
+	{
+	  delete [] __grouping;
+	  delete [] __truename;
+	  delete [] __falsename;
+	  __throw_exception_again;
+	}
+    }
+
+  // Used by both numeric and monetary facets.
+  // Check to make sure that the __grouping_tmp string constructed in
+  // money_get or num_get matches the canonical grouping for a given
+  // locale.
+  // __grouping_tmp is parsed L to R
+  // 1,222,444 == __grouping_tmp of "\1\3\3"
+  // __grouping is parsed R to L
+  // 1,222,444 == __grouping of "\3" == "\3\3\3"
+  _GLIBCXX_PURE bool
+  __verify_grouping(const char* __grouping, size_t __grouping_size,
+		    const string& __grouping_tmp) throw ();
+
+_GLIBCXX_BEGIN_NAMESPACE_LDBL
+
+  template<typename _CharT, typename _InIter>
+    _GLIBCXX_DEFAULT_ABI_TAG
+    _InIter
+    num_get<_CharT, _InIter>::
+    _M_extract_float(_InIter __beg, _InIter __end, ios_base& __io,
+		     ios_base::iostate& __err, string& __xtrc) const
+    {
+      typedef char_traits<_CharT>			__traits_type;
+      typedef __numpunct_cache<_CharT>                  __cache_type;
+      __use_cache<__cache_type> __uc;
+      const locale& __loc = __io._M_getloc();
+      const __cache_type* __lc = __uc(__loc);
+      const _CharT* __lit = __lc->_M_atoms_in;
+      char_type __c = char_type();
+
+      // True if __beg becomes equal to __end.
+      bool __testeof = __beg == __end;
+
+      // First check for sign.
+      if (!__testeof)
+	{
+	  __c = *__beg;
+	  const bool __plus = __c == __lit[__num_base::_S_iplus];
+	  if ((__plus || __c == __lit[__num_base::_S_iminus])
+	      && !(__lc->_M_use_grouping && __c == __lc->_M_thousands_sep)
+	      && !(__c == __lc->_M_decimal_point))
+	    {
+	      __xtrc += __plus ? '+' : '-';
+	      if (++__beg != __end)
+		__c = *__beg;
+	      else
+		__testeof = true;
+	    }
+	}
+
+      // Next, look for leading zeros.
+      bool __found_mantissa = false;
+      int __sep_pos = 0;
+      while (!__testeof)
+	{
+	  if ((__lc->_M_use_grouping && __c == __lc->_M_thousands_sep)
+	      || __c == __lc->_M_decimal_point)
+	    break;
+	  else if (__c == __lit[__num_base::_S_izero])
+	    {
+	      if (!__found_mantissa)
+		{
+		  __xtrc += '0';
+		  __found_mantissa = true;
+		}
+	      ++__sep_pos;
+
+	      if (++__beg != __end)
+		__c = *__beg;
+	      else
+		__testeof = true;
+	    }
+	  else
+	    break;
+	}
+
+      // Only need acceptable digits for floating point numbers.
+      bool __found_dec = false;
+      bool __found_sci = false;
+      string __found_grouping;
+      if (__lc->_M_use_grouping)
+	__found_grouping.reserve(32);
+      const char_type* __lit_zero = __lit + __num_base::_S_izero;
+
+      if (!__lc->_M_allocated)
+	// "C" locale
+	while (!__testeof)
+	  {
+	    const int __digit = _M_find(__lit_zero, 10, __c);
+	    if (__digit != -1)
+	      {
+		__xtrc += '0' + __digit;
+		__found_mantissa = true;
+	      }
+	    else if (__c == __lc->_M_decimal_point
+		     && !__found_dec && !__found_sci)
+	      {
+		__xtrc += '.';
+		__found_dec = true;
+	      }
+	    else if ((__c == __lit[__num_base::_S_ie] 
+		      || __c == __lit[__num_base::_S_iE])
+		     && !__found_sci && __found_mantissa)
+	      {
+		// Scientific notation.
+		__xtrc += 'e';
+		__found_sci = true;
+		
+		// Remove optional plus or minus sign, if they exist.
+		if (++__beg != __end)
+		  {
+		    __c = *__beg;
+		    const bool __plus = __c == __lit[__num_base::_S_iplus];
+		    if (__plus || __c == __lit[__num_base::_S_iminus])
+		      __xtrc += __plus ? '+' : '-';
+		    else
+		      continue;
+		  }
+		else
+		  {
+		    __testeof = true;
+		    break;
+		  }
+	      }
+	    else
+	      break;
+
+	    if (++__beg != __end)
+	      __c = *__beg;
+	    else
+	      __testeof = true;
+	  }
+      else
+	while (!__testeof)
+	  {
+	    // According to 22.2.2.1.2, p8-9, first look for thousands_sep
+	    // and decimal_point.
+	    if (__lc->_M_use_grouping && __c == __lc->_M_thousands_sep)
+	      {
+		if (!__found_dec && !__found_sci)
+		  {
+		    // NB: Thousands separator at the beginning of a string
+		    // is a no-no, as is two consecutive thousands separators.
+		    if (__sep_pos)
+		      {
+			__found_grouping += static_cast<char>(__sep_pos);
+			__sep_pos = 0;
+		      }
+		    else
+		      {
+			// NB: __convert_to_v will not assign __v and will
+			// set the failbit.
+			__xtrc.clear();
+			break;
+		      }
+		  }
+		else
+		  break;
+	      }
+	    else if (__c == __lc->_M_decimal_point)
+	      {
+		if (!__found_dec && !__found_sci)
+		  {
+		    // If no grouping chars are seen, no grouping check
+		    // is applied. Therefore __found_grouping is adjusted
+		    // only if decimal_point comes after some thousands_sep.
+		    if (__found_grouping.size())
+		      __found_grouping += static_cast<char>(__sep_pos);
+		    __xtrc += '.';
+		    __found_dec = true;
+		  }
+		else
+		  break;
+	      }
+	    else
+	      {
+		const char_type* __q =
+		  __traits_type::find(__lit_zero, 10, __c);
+		if (__q)
+		  {
+		    __xtrc += '0' + (__q - __lit_zero);
+		    __found_mantissa = true;
+		    ++__sep_pos;
+		  }
+		else if ((__c == __lit[__num_base::_S_ie] 
+			  || __c == __lit[__num_base::_S_iE])
+			 && !__found_sci && __found_mantissa)
+		  {
+		    // Scientific notation.
+		    if (__found_grouping.size() && !__found_dec)
+		      __found_grouping += static_cast<char>(__sep_pos);
+		    __xtrc += 'e';
+		    __found_sci = true;
+		    
+		    // Remove optional plus or minus sign, if they exist.
+		    if (++__beg != __end)
+		      {
+			__c = *__beg;
+			const bool __plus = __c == __lit[__num_base::_S_iplus];
+			if ((__plus || __c == __lit[__num_base::_S_iminus])
+			    && !(__lc->_M_use_grouping
+				 && __c == __lc->_M_thousands_sep)
+			    && !(__c == __lc->_M_decimal_point))
+		      __xtrc += __plus ? '+' : '-';
+			else
+			  continue;
+		      }
+		    else
+		      {
+			__testeof = true;
+			break;
+		      }
+		  }
+		else
+		  break;
+	      }
+	    
+	    if (++__beg != __end)
+	      __c = *__beg;
+	    else
+	      __testeof = true;
+	  }
+
+      // Digit grouping is checked. If grouping and found_grouping don't
+      // match, then get very very upset, and set failbit.
+      if (__found_grouping.size())
+        {
+          // Add the ending grouping if a decimal or 'e'/'E' wasn't found.
+	  if (!__found_dec && !__found_sci)
+	    __found_grouping += static_cast<char>(__sep_pos);
+
+          if (!std::__verify_grouping(__lc->_M_grouping, 
+				      __lc->_M_grouping_size,
+				      __found_grouping))
+	    __err = ios_base::failbit;
+        }
+
+      return __beg;
+    }
+
+  template<typename _CharT, typename _InIter>
+    template<typename _ValueT>
+      _GLIBCXX_DEFAULT_ABI_TAG
+      _InIter
+      num_get<_CharT, _InIter>::
+      _M_extract_int(_InIter __beg, _InIter __end, ios_base& __io,
+		     ios_base::iostate& __err, _ValueT& __v) const
+      {
+        typedef char_traits<_CharT>			    __traits_type;
+	using __gnu_cxx::__add_unsigned;
+	typedef typename __add_unsigned<_ValueT>::__type    __unsigned_type;
+	typedef __numpunct_cache<_CharT>                    __cache_type;
+	__use_cache<__cache_type> __uc;
+	const locale& __loc = __io._M_getloc();
+	const __cache_type* __lc = __uc(__loc);
+	const _CharT* __lit = __lc->_M_atoms_in;
+	char_type __c = char_type();
+
+	// NB: Iff __basefield == 0, __base can change based on contents.
+	const ios_base::fmtflags __basefield = __io.flags()
+	                                       & ios_base::basefield;
+	const bool __oct = __basefield == ios_base::oct;
+	int __base = __oct ? 8 : (__basefield == ios_base::hex ? 16 : 10);
+
+	// True if __beg becomes equal to __end.
+	bool __testeof = __beg == __end;
+
+	// First check for sign.
+	bool __negative = false;
+	if (!__testeof)
+	  {
+	    __c = *__beg;
+	    __negative = __c == __lit[__num_base::_S_iminus];
+	    if ((__negative || __c == __lit[__num_base::_S_iplus])
+		&& !(__lc->_M_use_grouping && __c == __lc->_M_thousands_sep)
+		&& !(__c == __lc->_M_decimal_point))
+	      {
+		if (++__beg != __end)
+		  __c = *__beg;
+		else
+		  __testeof = true;
+	      }
+	  }
+
+	// Next, look for leading zeros and check required digits
+	// for base formats.
+	bool __found_zero = false;
+	int __sep_pos = 0;
+	while (!__testeof)
+	  {
+	    if ((__lc->_M_use_grouping && __c == __lc->_M_thousands_sep)
+		|| __c == __lc->_M_decimal_point)
+	      break;
+	    else if (__c == __lit[__num_base::_S_izero] 
+		     && (!__found_zero || __base == 10))
+	      {
+		__found_zero = true;
+		++__sep_pos;
+		if (__basefield == 0)
+		  __base = 8;
+		if (__base == 8)
+		  __sep_pos = 0;
+	      }
+	    else if (__found_zero
+		     && (__c == __lit[__num_base::_S_ix]
+			 || __c == __lit[__num_base::_S_iX]))
+	      {
+		if (__basefield == 0)
+		  __base = 16;
+		if (__base == 16)
+		  {
+		    __found_zero = false;
+		    __sep_pos = 0;
+		  }
+		else
+		  break;
+	      }
+	    else
+	      break;
+
+	    if (++__beg != __end)
+	      {
+		__c = *__beg;
+		if (!__found_zero)
+		  break;
+	      }
+	    else
+	      __testeof = true;
+	  }
+	
+	// At this point, base is determined. If not hex, only allow
+	// base digits as valid input.
+	const size_t __len = (__base == 16 ? __num_base::_S_iend
+			      - __num_base::_S_izero : __base);
+
+	// Extract.
+	typedef __gnu_cxx::__numeric_traits<_ValueT> __num_traits;
+	string __found_grouping;
+	if (__lc->_M_use_grouping)
+	  __found_grouping.reserve(32);
+	bool __testfail = false;
+	bool __testoverflow = false;
+	const __unsigned_type __max =
+	  (__negative && __num_traits::__is_signed)
+	  ? -static_cast<__unsigned_type>(__num_traits::__min)
+	  : __num_traits::__max;
+	const __unsigned_type __smax = __max / __base;
+	__unsigned_type __result = 0;
+	int __digit = 0;
+	const char_type* __lit_zero = __lit + __num_base::_S_izero;
+
+	if (!__lc->_M_allocated)
+	  // "C" locale
+	  while (!__testeof)
+	    {
+	      __digit = _M_find(__lit_zero, __len, __c);
+	      if (__digit == -1)
+		break;
+	      
+	      if (__result > __smax)
+		__testoverflow = true;
+	      else
+		{
+		  __result *= __base;
+		  __testoverflow |= __result > __max - __digit;
+		  __result += __digit;
+		  ++__sep_pos;
+		}
+	      
+	      if (++__beg != __end)
+		__c = *__beg;
+	      else
+		__testeof = true;
+	    }
+	else
+	  while (!__testeof)
+	    {
+	      // According to 22.2.2.1.2, p8-9, first look for thousands_sep
+	      // and decimal_point.
+	      if (__lc->_M_use_grouping && __c == __lc->_M_thousands_sep)
+		{
+		  // NB: Thousands separator at the beginning of a string
+		  // is a no-no, as is two consecutive thousands separators.
+		  if (__sep_pos)
+		    {
+		      __found_grouping += static_cast<char>(__sep_pos);
+		      __sep_pos = 0;
+		    }
+		  else
+		    {
+		      __testfail = true;
+		      break;
+		    }
+		}
+	      else if (__c == __lc->_M_decimal_point)
+		break;
+	      else
+		{
+		  const char_type* __q =
+		    __traits_type::find(__lit_zero, __len, __c);
+		  if (!__q)
+		    break;
+		  
+		  __digit = __q - __lit_zero;
+		  if (__digit > 15)
+		    __digit -= 6;
+		  if (__result > __smax)
+		    __testoverflow = true;
+		  else
+		    {
+		      __result *= __base;
+		      __testoverflow |= __result > __max - __digit;
+		      __result += __digit;
+		      ++__sep_pos;
+		    }
+		}
+	      
+	      if (++__beg != __end)
+		__c = *__beg;
+	      else
+		__testeof = true;
+	    }
+	
+	// Digit grouping is checked. If grouping and found_grouping don't
+	// match, then get very very upset, and set failbit.
+	if (__found_grouping.size())
+	  {
+	    // Add the ending grouping.
+	    __found_grouping += static_cast<char>(__sep_pos);
+
+	    if (!std::__verify_grouping(__lc->_M_grouping,
+					__lc->_M_grouping_size,
+					__found_grouping))
+	      __err = ios_base::failbit;
+	  }
+
+	// _GLIBCXX_RESOLVE_LIB_DEFECTS
+	// 23. Num_get overflow result.
+	if ((!__sep_pos && !__found_zero && !__found_grouping.size())
+	    || __testfail)
+	  {
+	    __v = 0;
+	    __err = ios_base::failbit;
+	  }
+	else if (__testoverflow)
+	  {
+	    if (__negative && __num_traits::__is_signed)
+	      __v = __num_traits::__min;
+	    else
+	      __v = __num_traits::__max;
+	    __err = ios_base::failbit;
+	  }
+	else
+	  __v = __negative ? -__result : __result;
+
+	if (__testeof)
+	  __err |= ios_base::eofbit;
+	return __beg;
+      }
+
+  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+  // 17.  Bad bool parsing
+  template<typename _CharT, typename _InIter>
+    _InIter
+    num_get<_CharT, _InIter>::
+    do_get(iter_type __beg, iter_type __end, ios_base& __io,
+           ios_base::iostate& __err, bool& __v) const
+    {
+      if (!(__io.flags() & ios_base::boolalpha))
+        {
+	  // Parse bool values as long.
+          // NB: We can't just call do_get(long) here, as it might
+          // refer to a derived class.
+	  long __l = -1;
+          __beg = _M_extract_int(__beg, __end, __io, __err, __l);
+	  if (__l == 0 || __l == 1)
+	    __v = bool(__l);
+	  else
+	    {
+	      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+	      // 23. Num_get overflow result.
+	      __v = true;
+	      __err = ios_base::failbit;
+	      if (__beg == __end)
+		__err |= ios_base::eofbit;
+	    }
+        }
+      else
+        {
+	  // Parse bool values as alphanumeric.
+	  typedef __numpunct_cache<_CharT>  __cache_type;
+	  __use_cache<__cache_type> __uc;
+	  const locale& __loc = __io._M_getloc();
+	  const __cache_type* __lc = __uc(__loc);
+
+	  bool __testf = true;
+	  bool __testt = true;
+	  bool __donef = __lc->_M_falsename_size == 0;
+	  bool __donet = __lc->_M_truename_size == 0;
+	  bool __testeof = false;
+	  size_t __n = 0;
+	  while (!__donef || !__donet)
+	    {
+	      if (__beg == __end)
+		{
+		  __testeof = true;
+		  break;
+		}
+
+	      const char_type __c = *__beg;
+
+	      if (!__donef)
+		__testf = __c == __lc->_M_falsename[__n];
+
+	      if (!__testf && __donet)
+		break;
+
+	      if (!__donet)
+		__testt = __c == __lc->_M_truename[__n];
+
+	      if (!__testt && __donef)
+		break;
+
+	      if (!__testt && !__testf)
+		break;
+
+	      ++__n;
+	      ++__beg;
+
+	      __donef = !__testf || __n >= __lc->_M_falsename_size;
+	      __donet = !__testt || __n >= __lc->_M_truename_size;
+	    }
+	  if (__testf && __n == __lc->_M_falsename_size && __n)
+	    {
+	      __v = false;
+	      if (__testt && __n == __lc->_M_truename_size)
+		__err = ios_base::failbit;
+	      else
+		__err = __testeof ? ios_base::eofbit : ios_base::goodbit;
+	    }
+	  else if (__testt && __n == __lc->_M_truename_size && __n)
+	    {
+	      __v = true;
+	      __err = __testeof ? ios_base::eofbit : ios_base::goodbit;
+	    }
+	  else
+	    {
+	      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+	      // 23. Num_get overflow result.
+	      __v = false;
+	      __err = ios_base::failbit;
+	      if (__testeof)
+		__err |= ios_base::eofbit;
+	    }
+	}
+      return __beg;
+    }
+
+  template<typename _CharT, typename _InIter>
+    _InIter
+    num_get<_CharT, _InIter>::
+    do_get(iter_type __beg, iter_type __end, ios_base& __io,
+	   ios_base::iostate& __err, float& __v) const
+    {
+      string __xtrc;
+      __xtrc.reserve(32);
+      __beg = _M_extract_float(__beg, __end, __io, __err, __xtrc);
+      std::__convert_to_v(__xtrc.c_str(), __v, __err, _S_get_c_locale());
+      if (__beg == __end)
+	__err |= ios_base::eofbit;
+      return __beg;
+    }
+
+  template<typename _CharT, typename _InIter>
+    _InIter
+    num_get<_CharT, _InIter>::
+    do_get(iter_type __beg, iter_type __end, ios_base& __io,
+           ios_base::iostate& __err, double& __v) const
+    {
+      string __xtrc;
+      __xtrc.reserve(32);
+      __beg = _M_extract_float(__beg, __end, __io, __err, __xtrc);
+      std::__convert_to_v(__xtrc.c_str(), __v, __err, _S_get_c_locale());
+      if (__beg == __end)
+	__err |= ios_base::eofbit;
+      return __beg;
+    }
+
+#if defined _GLIBCXX_LONG_DOUBLE_COMPAT && defined __LONG_DOUBLE_128__
+  template<typename _CharT, typename _InIter>
+    _InIter
+    num_get<_CharT, _InIter>::
+    __do_get(iter_type __beg, iter_type __end, ios_base& __io,
+	     ios_base::iostate& __err, double& __v) const
+    {
+      string __xtrc;
+      __xtrc.reserve(32);
+      __beg = _M_extract_float(__beg, __end, __io, __err, __xtrc);
+      std::__convert_to_v(__xtrc.c_str(), __v, __err, _S_get_c_locale());
+      if (__beg == __end)
+	__err |= ios_base::eofbit;
+      return __beg;
+    }
+#endif
+
+  template<typename _CharT, typename _InIter>
+    _InIter
+    num_get<_CharT, _InIter>::
+    do_get(iter_type __beg, iter_type __end, ios_base& __io,
+           ios_base::iostate& __err, long double& __v) const
+    {
+      string __xtrc;
+      __xtrc.reserve(32);
+      __beg = _M_extract_float(__beg, __end, __io, __err, __xtrc);
+      std::__convert_to_v(__xtrc.c_str(), __v, __err, _S_get_c_locale());
+      if (__beg == __end)
+	__err |= ios_base::eofbit;
+      return __beg;
+    }
+
+  template<typename _CharT, typename _InIter>
+    _InIter
+    num_get<_CharT, _InIter>::
+    do_get(iter_type __beg, iter_type __end, ios_base& __io,
+           ios_base::iostate& __err, void*& __v) const
+    {
+      // Prepare for hex formatted input.
+      typedef ios_base::fmtflags        fmtflags;
+      const fmtflags __fmt = __io.flags();
+      __io.flags((__fmt & ~ios_base::basefield) | ios_base::hex);
+
+      typedef __gnu_cxx::__conditional_type<(sizeof(void*)
+					     <= sizeof(unsigned long)),
+	unsigned long, unsigned long long>::__type _UIntPtrType;       
+
+      _UIntPtrType __ul;
+      __beg = _M_extract_int(__beg, __end, __io, __err, __ul);
+
+      // Reset from hex formatted input.
+      __io.flags(__fmt);
+
+      __v = reinterpret_cast<void*>(__ul);
+      return __beg;
+    }
+
+#if defined _GLIBCXX_LONG_DOUBLE_ALT128_COMPAT \
+      && defined __LONG_DOUBLE_IEEE128__
+  template<typename _CharT, typename _InIter>
+    _InIter
+    num_get<_CharT, _InIter>::
+    __do_get(iter_type __beg, iter_type __end, ios_base& __io,
+	     ios_base::iostate& __err, __ibm128& __v) const
+    {
+      string __xtrc;
+      __xtrc.reserve(32);
+      __beg = _M_extract_float(__beg, __end, __io, __err, __xtrc);
+      std::__convert_to_v(__xtrc.c_str(), __v, __err, _S_get_c_locale());
+      if (__beg == __end)
+	__err |= ios_base::eofbit;
+      return __beg;
+    }
+#endif
+
+  // For use by integer and floating-point types after they have been
+  // converted into a char_type string.
+  template<typename _CharT, typename _OutIter>
+    void
+    num_put<_CharT, _OutIter>::
+    _M_pad(_CharT __fill, streamsize __w, ios_base& __io,
+	   _CharT* __new, const _CharT* __cs, int& __len) const
+    {
+      // [22.2.2.2.2] Stage 3.
+      // If necessary, pad.
+      __pad<_CharT, char_traits<_CharT> >::_S_pad(__io, __fill, __new,
+						  __cs, __w, __len);
+      __len = static_cast<int>(__w);
+    }
+
+_GLIBCXX_END_NAMESPACE_LDBL
+
+  template<typename _CharT, typename _ValueT>
+    int
+    __int_to_char(_CharT* __bufend, _ValueT __v, const _CharT* __lit,
+		  ios_base::fmtflags __flags, bool __dec)
+    {
+      _CharT* __buf = __bufend;
+      if (__builtin_expect(__dec, true))
+	{
+	  // Decimal.
+	  do
+	    {
+	      *--__buf = __lit[(__v % 10) + __num_base::_S_odigits];
+	      __v /= 10;
+	    }
+	  while (__v != 0);
+	}
+      else if ((__flags & ios_base::basefield) == ios_base::oct)
+	{
+	  // Octal.
+	  do
+	    {
+	      *--__buf = __lit[(__v & 0x7) + __num_base::_S_odigits];
+	      __v >>= 3;
+	    }
+	  while (__v != 0);
+	}
+      else
+	{
+	  // Hex.
+	  const bool __uppercase = __flags & ios_base::uppercase;
+	  const int __case_offset = __uppercase ? __num_base::_S_oudigits
+	                                        : __num_base::_S_odigits;
+	  do
+	    {
+	      *--__buf = __lit[(__v & 0xf) + __case_offset];
+	      __v >>= 4;
+	    }
+	  while (__v != 0);
+	}
+      return __bufend - __buf;
+    }
+
+_GLIBCXX_BEGIN_NAMESPACE_LDBL
+
+  template<typename _CharT, typename _OutIter>
+    void
+    num_put<_CharT, _OutIter>::
+    _M_group_int(const char* __grouping, size_t __grouping_size, _CharT __sep,
+		 ios_base&, _CharT* __new, _CharT* __cs, int& __len) const
+    {
+      _CharT* __p = std::__add_grouping(__new, __sep, __grouping,
+					__grouping_size, __cs, __cs + __len);
+      __len = __p - __new;
+    }
+  
+  template<typename _CharT, typename _OutIter>
+    template<typename _ValueT>
+      _OutIter
+      num_put<_CharT, _OutIter>::
+      _M_insert_int(_OutIter __s, ios_base& __io, _CharT __fill,
+		    _ValueT __v) const
+      {
+	using __gnu_cxx::__add_unsigned;
+	typedef typename __add_unsigned<_ValueT>::__type __unsigned_type;
+	typedef __numpunct_cache<_CharT>	             __cache_type;
+	__use_cache<__cache_type> __uc;
+	const locale& __loc = __io._M_getloc();
+	const __cache_type* __lc = __uc(__loc);
+	const _CharT* __lit = __lc->_M_atoms_out;
+	const ios_base::fmtflags __flags = __io.flags();
+
+	// Long enough to hold hex, dec, and octal representations.
+	const int __ilen = 5 * sizeof(_ValueT);
+	_CharT* __cs = static_cast<_CharT*>(__builtin_alloca(sizeof(_CharT)
+							     * __ilen));
+
+	// [22.2.2.2.2] Stage 1, numeric conversion to character.
+	// Result is returned right-justified in the buffer.
+	const ios_base::fmtflags __basefield = __flags & ios_base::basefield;
+	const bool __dec = (__basefield != ios_base::oct
+			    && __basefield != ios_base::hex);
+	const __unsigned_type __u = ((__v > 0 || !__dec)
+				     ? __unsigned_type(__v)
+				     : -__unsigned_type(__v));
+ 	int __len = __int_to_char(__cs + __ilen, __u, __lit, __flags, __dec);
+	__cs += __ilen - __len;
+
+	// Add grouping, if necessary.
+	if (__lc->_M_use_grouping)
+	  {
+	    // Grouping can add (almost) as many separators as the number
+	    // of digits + space is reserved for numeric base or sign.
+	    _CharT* __cs2 = static_cast<_CharT*>(__builtin_alloca(sizeof(_CharT)
+								  * (__len + 1)
+								  * 2));
+	    _M_group_int(__lc->_M_grouping, __lc->_M_grouping_size,
+			 __lc->_M_thousands_sep, __io, __cs2 + 2, __cs, __len);
+	    __cs = __cs2 + 2;
+	  }
+
+	// Complete Stage 1, prepend numeric base or sign.
+	if (__builtin_expect(__dec, true))
+	  {
+	    // Decimal.
+	    if (__v >= 0)
+	      {
+		if (bool(__flags & ios_base::showpos)
+		    && __gnu_cxx::__numeric_traits<_ValueT>::__is_signed)
+		  *--__cs = __lit[__num_base::_S_oplus], ++__len;
+	      }
+	    else
+	      *--__cs = __lit[__num_base::_S_ominus], ++__len;
+	  }
+	else if (bool(__flags & ios_base::showbase) && __v)
+	  {
+	    if (__basefield == ios_base::oct)
+	      *--__cs = __lit[__num_base::_S_odigits], ++__len;
+	    else
+	      {
+		// 'x' or 'X'
+		const bool __uppercase = __flags & ios_base::uppercase;
+		*--__cs = __lit[__num_base::_S_ox + __uppercase];
+		// '0'
+		*--__cs = __lit[__num_base::_S_odigits];
+		__len += 2;
+	      }
+	  }
+
+	// Pad.
+	const streamsize __w = __io.width();
+	if (__w > static_cast<streamsize>(__len))
+	  {
+	    _CharT* __cs3 = static_cast<_CharT*>(__builtin_alloca(sizeof(_CharT)
+								  * __w));
+	    _M_pad(__fill, __w, __io, __cs3, __cs, __len);
+	    __cs = __cs3;
+	  }
+	__io.width(0);
+
+	// [22.2.2.2.2] Stage 4.
+	// Write resulting, fully-formatted string to output iterator.
+	return std::__write(__s, __cs, __len);
+      }
+
+  template<typename _CharT, typename _OutIter>
+    void
+    num_put<_CharT, _OutIter>::
+    _M_group_float(const char* __grouping, size_t __grouping_size,
+		   _CharT __sep, const _CharT* __p, _CharT* __new,
+		   _CharT* __cs, int& __len) const
+    {
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 282. What types does numpunct grouping refer to?
+      // Add grouping, if necessary.
+      const int __declen = __p ? __p - __cs : __len;
+      _CharT* __p2 = std::__add_grouping(__new, __sep, __grouping,
+					 __grouping_size,
+					 __cs, __cs + __declen);
+
+      // Tack on decimal part.
+      int __newlen = __p2 - __new;
+      if (__p)
+	{
+	  char_traits<_CharT>::copy(__p2, __p, __len - __declen);
+	  __newlen += __len - __declen;
+	}
+      __len = __newlen;
+    }
+
+  // The following code uses vsnprintf (or vsprintf(), when
+  // _GLIBCXX_USE_C99_STDIO is not defined) to convert floating point
+  // values for insertion into a stream.  An optimization would be to
+  // replace them with code that works directly on a wide buffer and
+  // then use __pad to do the padding.  It would be good to replace
+  // them anyway to gain back the efficiency that C++ provides by
+  // knowing up front the type of the values to insert.  Also, sprintf
+  // is dangerous since may lead to accidental buffer overruns.  This
+  // implementation follows the C++ standard fairly directly as
+  // outlined in 22.2.2.2 [lib.locale.num.put]
+  template<typename _CharT, typename _OutIter>
+    template<typename _ValueT>
+      _OutIter
+      num_put<_CharT, _OutIter>::
+      _M_insert_float(_OutIter __s, ios_base& __io, _CharT __fill, char __mod,
+		       _ValueT __v) const
+      {
+	typedef __numpunct_cache<_CharT>                __cache_type;
+	__use_cache<__cache_type> __uc;
+	const locale& __loc = __io._M_getloc();
+	const __cache_type* __lc = __uc(__loc);
+
+	// Use default precision if out of range.
+	const streamsize __prec = __io.precision() < 0 ? 6 : __io.precision();
+
+	const int __max_digits =
+	  __gnu_cxx::__numeric_traits<_ValueT>::__digits10;
+
+	// [22.2.2.2.2] Stage 1, numeric conversion to character.
+	int __len;
+	// Long enough for the max format spec.
+	char __fbuf[16];
+	__num_base::_S_format_float(__io, __fbuf, __mod);
+
+#if _GLIBCXX_USE_C99_STDIO && !_GLIBCXX_HAVE_BROKEN_VSNPRINTF
+	// Precision is always used except for hexfloat format.
+	const bool __use_prec =
+	  (__io.flags() & ios_base::floatfield) != ios_base::floatfield;
+
+	// First try a buffer perhaps big enough (most probably sufficient
+	// for non-ios_base::fixed outputs)
+	int __cs_size = __max_digits * 3;
+	char* __cs = static_cast<char*>(__builtin_alloca(__cs_size));
+	if (__use_prec)
+	  __len = std::__convert_from_v(_S_get_c_locale(), __cs, __cs_size,
+					__fbuf, __prec, __v);
+	else
+	  __len = std::__convert_from_v(_S_get_c_locale(), __cs, __cs_size,
+					__fbuf, __v);
+
+	// If the buffer was not large enough, try again with the correct size.
+	if (__len >= __cs_size)
+	  {
+	    __cs_size = __len + 1;
+	    __cs = static_cast<char*>(__builtin_alloca(__cs_size));
+	    if (__use_prec)
+	      __len = std::__convert_from_v(_S_get_c_locale(), __cs, __cs_size,
+					    __fbuf, __prec, __v);
+	    else
+	      __len = std::__convert_from_v(_S_get_c_locale(), __cs, __cs_size,
+					    __fbuf, __v);
+	  }
+#else
+	// Consider the possibility of long ios_base::fixed outputs
+	const bool __fixed = __io.flags() & ios_base::fixed;
+	const int __max_exp =
+	  __gnu_cxx::__numeric_traits<_ValueT>::__max_exponent10;
+
+	// The size of the output string is computed as follows.
+	// ios_base::fixed outputs may need up to __max_exp + 1 chars
+	// for the integer part + __prec chars for the fractional part
+	// + 3 chars for sign, decimal point, '\0'. On the other hand,
+	// for non-fixed outputs __max_digits * 2 + __prec chars are
+	// largely sufficient.
+	const int __cs_size = __fixed ? __max_exp + __prec + 4
+	                              : __max_digits * 2 + __prec;
+	char* __cs = static_cast<char*>(__builtin_alloca(__cs_size));
+	__len = std::__convert_from_v(_S_get_c_locale(), __cs, 0, __fbuf, 
+				      __prec, __v);
+#endif
+
+	// [22.2.2.2.2] Stage 2, convert to char_type, using correct
+	// numpunct.decimal_point() values for '.' and adding grouping.
+	const ctype<_CharT>& __ctype = use_facet<ctype<_CharT> >(__loc);
+	
+	_CharT* __ws = static_cast<_CharT*>(__builtin_alloca(sizeof(_CharT)
+							     * __len));
+	__ctype.widen(__cs, __cs + __len, __ws);
+	
+	// Replace decimal point.
+	_CharT* __wp = 0;
+	const char* __p = char_traits<char>::find(__cs, __len, '.');
+	if (__p)
+	  {
+	    __wp = __ws + (__p - __cs);
+	    *__wp = __lc->_M_decimal_point;
+	  }
+	
+	// Add grouping, if necessary.
+	// N.B. Make sure to not group things like 2e20, i.e., no decimal
+	// point, scientific notation.
+	if (__lc->_M_use_grouping
+	    && (__wp || __len < 3 || (__cs[1] <= '9' && __cs[2] <= '9'
+				      && __cs[1] >= '0' && __cs[2] >= '0')))
+	  {
+	    // Grouping can add (almost) as many separators as the
+	    // number of digits, but no more.
+	    _CharT* __ws2 = static_cast<_CharT*>(__builtin_alloca(sizeof(_CharT)
+								  * __len * 2));
+	    
+	    streamsize __off = 0;
+	    if (__cs[0] == '-' || __cs[0] == '+')
+	      {
+		__off = 1;
+		__ws2[0] = __ws[0];
+		__len -= 1;
+	      }
+	    
+	    _M_group_float(__lc->_M_grouping, __lc->_M_grouping_size,
+			   __lc->_M_thousands_sep, __wp, __ws2 + __off,
+			   __ws + __off, __len);
+	    __len += __off;
+	    
+	    __ws = __ws2;
+	  }
+
+	// Pad.
+	const streamsize __w = __io.width();
+	if (__w > static_cast<streamsize>(__len))
+	  {
+	    _CharT* __ws3 = static_cast<_CharT*>(__builtin_alloca(sizeof(_CharT)
+								  * __w));
+	    _M_pad(__fill, __w, __io, __ws3, __ws, __len);
+	    __ws = __ws3;
+	  }
+	__io.width(0);
+	
+	// [22.2.2.2.2] Stage 4.
+	// Write resulting, fully-formatted string to output iterator.
+	return std::__write(__s, __ws, __len);
+      }
+  
+  template<typename _CharT, typename _OutIter>
+    _OutIter
+    num_put<_CharT, _OutIter>::
+    do_put(iter_type __s, ios_base& __io, char_type __fill, bool __v) const
+    {
+      const ios_base::fmtflags __flags = __io.flags();
+      if ((__flags & ios_base::boolalpha) == 0)
+        {
+          const long __l = __v;
+          __s = _M_insert_int(__s, __io, __fill, __l);
+        }
+      else
+        {
+	  typedef __numpunct_cache<_CharT>              __cache_type;
+	  __use_cache<__cache_type> __uc;
+	  const locale& __loc = __io._M_getloc();
+	  const __cache_type* __lc = __uc(__loc);
+
+	  const _CharT* __name = __v ? __lc->_M_truename
+	                             : __lc->_M_falsename;
+	  int __len = __v ? __lc->_M_truename_size
+	                  : __lc->_M_falsename_size;
+
+	  const streamsize __w = __io.width();
+	  if (__w > static_cast<streamsize>(__len))
+	    {
+	      const streamsize __plen = __w - __len;
+	      _CharT* __ps
+		= static_cast<_CharT*>(__builtin_alloca(sizeof(_CharT)
+							* __plen));
+
+	      char_traits<_CharT>::assign(__ps, __plen, __fill);
+	      __io.width(0);
+
+	      if ((__flags & ios_base::adjustfield) == ios_base::left)
+		{
+		  __s = std::__write(__s, __name, __len);
+		  __s = std::__write(__s, __ps, __plen);
+		}
+	      else
+		{
+		  __s = std::__write(__s, __ps, __plen);
+		  __s = std::__write(__s, __name, __len);
+		}
+	      return __s;
+	    }
+	  __io.width(0);
+	  __s = std::__write(__s, __name, __len);
+	}
+      return __s;
+    }
+
+  template<typename _CharT, typename _OutIter>
+    _OutIter
+    num_put<_CharT, _OutIter>::
+    do_put(iter_type __s, ios_base& __io, char_type __fill, double __v) const
+    { return _M_insert_float(__s, __io, __fill, char(), __v); }
+
+#if defined _GLIBCXX_LONG_DOUBLE_COMPAT && defined __LONG_DOUBLE_128__
+  template<typename _CharT, typename _OutIter>
+    _OutIter
+    num_put<_CharT, _OutIter>::
+    __do_put(iter_type __s, ios_base& __io, char_type __fill, double __v) const
+    { return _M_insert_float(__s, __io, __fill, char(), __v); }
+#endif
+
+  template<typename _CharT, typename _OutIter>
+    _OutIter
+    num_put<_CharT, _OutIter>::
+    do_put(iter_type __s, ios_base& __io, char_type __fill,
+	   long double __v) const
+    { return _M_insert_float(__s, __io, __fill, 'L', __v); }
+
+  template<typename _CharT, typename _OutIter>
+    _OutIter
+    num_put<_CharT, _OutIter>::
+    do_put(iter_type __s, ios_base& __io, char_type __fill,
+           const void* __v) const
+    {
+      const ios_base::fmtflags __flags = __io.flags();
+      const ios_base::fmtflags __fmt = ~(ios_base::basefield
+					 | ios_base::uppercase);
+      __io.flags((__flags & __fmt) | (ios_base::hex | ios_base::showbase));
+
+      typedef __gnu_cxx::__conditional_type<(sizeof(const void*)
+					     <= sizeof(unsigned long)),
+	unsigned long, unsigned long long>::__type _UIntPtrType;       
+
+      __s = _M_insert_int(__s, __io, __fill,
+			  reinterpret_cast<_UIntPtrType>(__v));
+      __io.flags(__flags);
+      return __s;
+    }
+
+#if defined _GLIBCXX_LONG_DOUBLE_ALT128_COMPAT \
+      && defined __LONG_DOUBLE_IEEE128__
+  template<typename _CharT, typename _OutIter>
+    _OutIter
+    num_put<_CharT, _OutIter>::
+    __do_put(iter_type __s, ios_base& __io, char_type __fill,
+	     __ibm128 __v) const
+    { return _M_insert_float(__s, __io, __fill, 'L', __v); }
+#endif
+_GLIBCXX_END_NAMESPACE_LDBL
+
+  // Construct correctly padded string, as per 22.2.2.2.2
+  // Assumes
+  // __newlen > __oldlen
+  // __news is allocated for __newlen size
+
+  // NB: Of the two parameters, _CharT can be deduced from the
+  // function arguments. The other (_Traits) has to be explicitly specified.
+  template<typename _CharT, typename _Traits>
+    void
+    __pad<_CharT, _Traits>::_S_pad(ios_base& __io, _CharT __fill,
+				   _CharT* __news, const _CharT* __olds,
+				   streamsize __newlen, streamsize __oldlen)
+    {
+      const size_t __plen = static_cast<size_t>(__newlen - __oldlen);
+      const ios_base::fmtflags __adjust = __io.flags() & ios_base::adjustfield;
+
+      // Padding last.
+      if (__adjust == ios_base::left)
+	{
+	  _Traits::copy(__news, __olds, __oldlen);
+	  _Traits::assign(__news + __oldlen, __plen, __fill);
+	  return;
+	}
+
+      size_t __mod = 0;
+      if (__adjust == ios_base::internal)
+	{
+	  // Pad after the sign, if there is one.
+	  // Pad after 0[xX], if there is one.
+	  // Who came up with these rules, anyway? Jeeze.
+          const locale& __loc = __io._M_getloc();
+	  const ctype<_CharT>& __ctype = use_facet<ctype<_CharT> >(__loc);
+
+	  if (__ctype.widen('-') == __olds[0]
+	      || __ctype.widen('+') == __olds[0])
+	    {
+	      __news[0] = __olds[0];
+	      __mod = 1;
+	      ++__news;
+	    }
+	  else if (__ctype.widen('0') == __olds[0]
+		   && __oldlen > 1
+		   && (__ctype.widen('x') == __olds[1]
+		       || __ctype.widen('X') == __olds[1]))
+	    {
+	      __news[0] = __olds[0];
+	      __news[1] = __olds[1];
+	      __mod = 2;
+	      __news += 2;
+	    }
+	  // else Padding first.
+	}
+      _Traits::assign(__news, __plen, __fill);
+      _Traits::copy(__news + __plen, __olds + __mod, __oldlen - __mod);
+    }
+
+  template<typename _CharT>
+    _CharT*
+    __add_grouping(_CharT* __s, _CharT __sep,
+		   const char* __gbeg, size_t __gsize,
+		   const _CharT* __first, const _CharT* __last)
+    {
+      size_t __idx = 0;
+      size_t __ctr = 0;
+
+      while (__last - __first > __gbeg[__idx]
+	     && static_cast<signed char>(__gbeg[__idx]) > 0
+	     && __gbeg[__idx] != __gnu_cxx::__numeric_traits<char>::__max)
+	{
+	  __last -= __gbeg[__idx];
+	  __idx < __gsize - 1 ? ++__idx : ++__ctr;
+	}
+
+      while (__first != __last)
+	*__s++ = *__first++;
+
+      while (__ctr--)
+	{
+	  *__s++ = __sep;	  
+	  for (char __i = __gbeg[__idx]; __i > 0; --__i)
+	    *__s++ = *__first++;
+	}
+
+      while (__idx--)
+	{
+	  *__s++ = __sep;	  
+	  for (char __i = __gbeg[__idx]; __i > 0; --__i)
+	    *__s++ = *__first++;
+	}
+
+      return __s;
+    }
+
+  // Inhibit implicit instantiations for required instantiations,
+  // which are defined via explicit instantiations elsewhere.
+#if _GLIBCXX_EXTERN_TEMPLATE
+  extern template class _GLIBCXX_NAMESPACE_CXX11 numpunct<char>;
+  extern template class _GLIBCXX_NAMESPACE_CXX11 numpunct_byname<char>;
+  extern template class _GLIBCXX_NAMESPACE_LDBL num_get<char>;
+  extern template class _GLIBCXX_NAMESPACE_LDBL num_put<char>;
+  extern template class ctype_byname<char>;
+
+  extern template
+    const ctype<char>&
+    use_facet<ctype<char> >(const locale&);
+
+  extern template
+    const numpunct<char>&
+    use_facet<numpunct<char> >(const locale&);
+
+  extern template
+    const num_put<char>&
+    use_facet<num_put<char> >(const locale&);
+
+  extern template
+    const num_get<char>&
+    use_facet<num_get<char> >(const locale&);
+
+  extern template
+    bool
+    has_facet<ctype<char> >(const locale&);
+
+  extern template
+    bool
+    has_facet<numpunct<char> >(const locale&);
+
+  extern template
+    bool
+    has_facet<num_put<char> >(const locale&);
+
+  extern template
+    bool
+    has_facet<num_get<char> >(const locale&);
+
+#ifdef _GLIBCXX_USE_WCHAR_T
+  extern template class _GLIBCXX_NAMESPACE_CXX11 numpunct<wchar_t>;
+  extern template class _GLIBCXX_NAMESPACE_CXX11 numpunct_byname<wchar_t>;
+  extern template class _GLIBCXX_NAMESPACE_LDBL num_get<wchar_t>;
+  extern template class _GLIBCXX_NAMESPACE_LDBL num_put<wchar_t>;
+  extern template class ctype_byname<wchar_t>;
+
+  extern template
+    const ctype<wchar_t>&
+    use_facet<ctype<wchar_t> >(const locale&);
+
+  extern template
+    const numpunct<wchar_t>&
+    use_facet<numpunct<wchar_t> >(const locale&);
+
+  extern template
+    const num_put<wchar_t>&
+    use_facet<num_put<wchar_t> >(const locale&);
+
+  extern template
+    const num_get<wchar_t>&
+    use_facet<num_get<wchar_t> >(const locale&);
+
+ extern template
+    bool
+    has_facet<ctype<wchar_t> >(const locale&);
+
+  extern template
+    bool
+    has_facet<numpunct<wchar_t> >(const locale&);
+
+  extern template
+    bool
+    has_facet<num_put<wchar_t> >(const locale&);
+
+  extern template
+    bool
+    has_facet<num_get<wchar_t> >(const locale&);
+#endif
+#endif
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif
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@@ -0,0 +1,2071 @@
+// Locale support -*- C++ -*-
+
+// Copyright (C) 2007-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/locale_facets_nonio.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{locale}
+ */
+
+//
+// ISO C++ 14882: 22.1  Locales
+//
+
+#ifndef _LOCALE_FACETS_NONIO_H
+#define _LOCALE_FACETS_NONIO_H 1
+
+#pragma GCC system_header
+
+#include <ctime>	// For struct tm
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /**
+   *  @brief  Time format ordering data.
+   *  @ingroup locales
+   *
+   *  This class provides an enum representing different orderings of
+   *  time: day, month, and year.
+  */
+  class time_base
+  {
+  public:
+    enum dateorder { no_order, dmy, mdy, ymd, ydm };
+  };
+
+  template<typename _CharT>
+    struct __timepunct_cache : public locale::facet
+    {
+      // List of all known timezones, with GMT first.
+      static const _CharT*		_S_timezones[14];
+
+      const _CharT*			_M_date_format;
+      const _CharT*			_M_date_era_format;
+      const _CharT*			_M_time_format;
+      const _CharT*			_M_time_era_format;
+      const _CharT*			_M_date_time_format;
+      const _CharT*			_M_date_time_era_format;
+      const _CharT*			_M_am;
+      const _CharT*			_M_pm;
+      const _CharT*			_M_am_pm_format;
+
+      // Day names, starting with "C"'s Sunday.
+      const _CharT*			_M_day1;
+      const _CharT*			_M_day2;
+      const _CharT*			_M_day3;
+      const _CharT*			_M_day4;
+      const _CharT*			_M_day5;
+      const _CharT*			_M_day6;
+      const _CharT*			_M_day7;
+
+      // Abbreviated day names, starting with "C"'s Sun.
+      const _CharT*			_M_aday1;
+      const _CharT*			_M_aday2;
+      const _CharT*			_M_aday3;
+      const _CharT*			_M_aday4;
+      const _CharT*			_M_aday5;
+      const _CharT*			_M_aday6;
+      const _CharT*			_M_aday7;
+
+      // Month names, starting with "C"'s January.
+      const _CharT*			_M_month01;
+      const _CharT*			_M_month02;
+      const _CharT*			_M_month03;
+      const _CharT*			_M_month04;
+      const _CharT*			_M_month05;
+      const _CharT*			_M_month06;
+      const _CharT*			_M_month07;
+      const _CharT*			_M_month08;
+      const _CharT*			_M_month09;
+      const _CharT*			_M_month10;
+      const _CharT*			_M_month11;
+      const _CharT*			_M_month12;
+
+      // Abbreviated month names, starting with "C"'s Jan.
+      const _CharT*			_M_amonth01;
+      const _CharT*			_M_amonth02;
+      const _CharT*			_M_amonth03;
+      const _CharT*			_M_amonth04;
+      const _CharT*			_M_amonth05;
+      const _CharT*			_M_amonth06;
+      const _CharT*			_M_amonth07;
+      const _CharT*			_M_amonth08;
+      const _CharT*			_M_amonth09;
+      const _CharT*			_M_amonth10;
+      const _CharT*			_M_amonth11;
+      const _CharT*			_M_amonth12;
+
+      bool				_M_allocated;
+
+      __timepunct_cache(size_t __refs = 0) : facet(__refs),
+      _M_date_format(0), _M_date_era_format(0), _M_time_format(0),
+      _M_time_era_format(0), _M_date_time_format(0),
+      _M_date_time_era_format(0), _M_am(0), _M_pm(0),
+      _M_am_pm_format(0), _M_day1(0), _M_day2(0), _M_day3(0),
+      _M_day4(0), _M_day5(0), _M_day6(0), _M_day7(0),
+      _M_aday1(0), _M_aday2(0), _M_aday3(0), _M_aday4(0),
+      _M_aday5(0), _M_aday6(0), _M_aday7(0), _M_month01(0),
+      _M_month02(0), _M_month03(0), _M_month04(0), _M_month05(0),
+      _M_month06(0), _M_month07(0), _M_month08(0), _M_month09(0),
+      _M_month10(0), _M_month11(0), _M_month12(0), _M_amonth01(0),
+      _M_amonth02(0), _M_amonth03(0), _M_amonth04(0),
+      _M_amonth05(0), _M_amonth06(0), _M_amonth07(0),
+      _M_amonth08(0), _M_amonth09(0), _M_amonth10(0),
+      _M_amonth11(0), _M_amonth12(0), _M_allocated(false)
+      { }
+
+      ~__timepunct_cache();
+
+    private:
+      __timepunct_cache&
+      operator=(const __timepunct_cache&);
+      
+      explicit
+      __timepunct_cache(const __timepunct_cache&);
+    };
+
+  template<typename _CharT>
+    __timepunct_cache<_CharT>::~__timepunct_cache()
+    {
+      if (_M_allocated)
+	{
+	  // Unused.
+	}
+    }
+
+  // Specializations.
+  template<>
+    const char*
+    __timepunct_cache<char>::_S_timezones[14];
+
+#ifdef _GLIBCXX_USE_WCHAR_T
+  template<>
+    const wchar_t*
+    __timepunct_cache<wchar_t>::_S_timezones[14];
+#endif
+
+  // Generic.
+  template<typename _CharT>
+    const _CharT* __timepunct_cache<_CharT>::_S_timezones[14];
+
+  template<typename _CharT>
+    class __timepunct : public locale::facet
+    {
+    public:
+      // Types:
+      typedef _CharT			__char_type;
+      typedef __timepunct_cache<_CharT>	__cache_type;
+
+    protected:
+      __cache_type*			_M_data;
+      __c_locale			_M_c_locale_timepunct;
+      const char*			_M_name_timepunct;
+
+    public:
+      /// Numpunct facet id.
+      static locale::id			id;
+
+      explicit
+      __timepunct(size_t __refs = 0);
+
+      explicit
+      __timepunct(__cache_type* __cache, size_t __refs = 0);
+
+      /**
+       *  @brief  Internal constructor. Not for general use.
+       *
+       *  This is a constructor for use by the library itself to set up new
+       *  locales.
+       *
+       *  @param __cloc  The C locale.
+       *  @param __s  The name of a locale.
+       *  @param refs  Passed to the base facet class.
+      */
+      explicit
+      __timepunct(__c_locale __cloc, const char* __s, size_t __refs = 0);
+
+      // FIXME: for error checking purposes _M_put should return the return
+      // value of strftime/wcsftime.
+      void
+      _M_put(_CharT* __s, size_t __maxlen, const _CharT* __format,
+	     const tm* __tm) const throw ();
+
+      void
+      _M_date_formats(const _CharT** __date) const
+      {
+	// Always have default first.
+	__date[0] = _M_data->_M_date_format;
+	__date[1] = _M_data->_M_date_era_format;
+      }
+
+      void
+      _M_time_formats(const _CharT** __time) const
+      {
+	// Always have default first.
+	__time[0] = _M_data->_M_time_format;
+	__time[1] = _M_data->_M_time_era_format;
+      }
+
+      void
+      _M_date_time_formats(const _CharT** __dt) const
+      {
+	// Always have default first.
+	__dt[0] = _M_data->_M_date_time_format;
+	__dt[1] = _M_data->_M_date_time_era_format;
+      }
+
+#if !_GLIBCXX_INLINE_VERSION
+      void
+      _M_am_pm_format(const _CharT*) const
+      { /* Kept for ABI compatibility, see PR65927 */ }
+#endif
+
+      void
+      _M_am_pm_format(const _CharT** __ampm_format) const
+      {
+	__ampm_format[0] = _M_data->_M_am_pm_format;
+      }
+
+      void
+      _M_am_pm(const _CharT** __ampm) const
+      {
+	__ampm[0] = _M_data->_M_am;
+	__ampm[1] = _M_data->_M_pm;
+      }
+
+      void
+      _M_days(const _CharT** __days) const
+      {
+	__days[0] = _M_data->_M_day1;
+	__days[1] = _M_data->_M_day2;
+	__days[2] = _M_data->_M_day3;
+	__days[3] = _M_data->_M_day4;
+	__days[4] = _M_data->_M_day5;
+	__days[5] = _M_data->_M_day6;
+	__days[6] = _M_data->_M_day7;
+      }
+
+      void
+      _M_days_abbreviated(const _CharT** __days) const
+      {
+	__days[0] = _M_data->_M_aday1;
+	__days[1] = _M_data->_M_aday2;
+	__days[2] = _M_data->_M_aday3;
+	__days[3] = _M_data->_M_aday4;
+	__days[4] = _M_data->_M_aday5;
+	__days[5] = _M_data->_M_aday6;
+	__days[6] = _M_data->_M_aday7;
+      }
+
+      void
+      _M_months(const _CharT** __months) const
+      {
+	__months[0] = _M_data->_M_month01;
+	__months[1] = _M_data->_M_month02;
+	__months[2] = _M_data->_M_month03;
+	__months[3] = _M_data->_M_month04;
+	__months[4] = _M_data->_M_month05;
+	__months[5] = _M_data->_M_month06;
+	__months[6] = _M_data->_M_month07;
+	__months[7] = _M_data->_M_month08;
+	__months[8] = _M_data->_M_month09;
+	__months[9] = _M_data->_M_month10;
+	__months[10] = _M_data->_M_month11;
+	__months[11] = _M_data->_M_month12;
+      }
+
+      void
+      _M_months_abbreviated(const _CharT** __months) const
+      {
+	__months[0] = _M_data->_M_amonth01;
+	__months[1] = _M_data->_M_amonth02;
+	__months[2] = _M_data->_M_amonth03;
+	__months[3] = _M_data->_M_amonth04;
+	__months[4] = _M_data->_M_amonth05;
+	__months[5] = _M_data->_M_amonth06;
+	__months[6] = _M_data->_M_amonth07;
+	__months[7] = _M_data->_M_amonth08;
+	__months[8] = _M_data->_M_amonth09;
+	__months[9] = _M_data->_M_amonth10;
+	__months[10] = _M_data->_M_amonth11;
+	__months[11] = _M_data->_M_amonth12;
+      }
+
+    protected:
+      virtual
+      ~__timepunct();
+
+      // For use at construction time only.
+      void
+      _M_initialize_timepunct(__c_locale __cloc = 0);
+    };
+
+  template<typename _CharT>
+    locale::id __timepunct<_CharT>::id;
+
+  // Specializations.
+  template<>
+    void
+    __timepunct<char>::_M_initialize_timepunct(__c_locale __cloc);
+
+  template<>
+    void
+    __timepunct<char>::_M_put(char*, size_t, const char*, const tm*) const throw ();
+
+#ifdef _GLIBCXX_USE_WCHAR_T
+  template<>
+    void
+    __timepunct<wchar_t>::_M_initialize_timepunct(__c_locale __cloc);
+
+  template<>
+    void
+    __timepunct<wchar_t>::_M_put(wchar_t*, size_t, const wchar_t*,
+				 const tm*) const throw ();
+#endif
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+  // Include host and configuration specific timepunct functions.
+  #include <bits/time_members.h>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  struct __time_get_state
+  {
+    // Finalize state.
+    void
+    _M_finalize_state(tm* __tm);
+
+    unsigned int _M_have_I : 1;
+    unsigned int _M_have_wday : 1;
+    unsigned int _M_have_yday : 1;
+    unsigned int _M_have_mon : 1;
+    unsigned int _M_have_mday : 1;
+    unsigned int _M_have_uweek : 1;
+    unsigned int _M_have_wweek : 1;
+    unsigned int _M_have_century : 1;
+    unsigned int _M_is_pm : 1;
+    unsigned int _M_want_century : 1;
+    unsigned int _M_want_xday : 1;
+    unsigned int _M_pad1 : 5;
+    unsigned int _M_week_no : 6;
+    unsigned int _M_pad2 : 10;
+    int _M_century;
+    int _M_pad3;
+  };
+
+_GLIBCXX_BEGIN_NAMESPACE_CXX11
+
+  /**
+   *  @brief  Primary class template time_get.
+   *  @ingroup locales
+   *
+   *  This facet encapsulates the code to parse and return a date or
+   *  time from a string.  It is used by the istream numeric
+   *  extraction operators.
+   *
+   *  The time_get template uses protected virtual functions to provide the
+   *  actual results.  The public accessors forward the call to the virtual
+   *  functions.  These virtual functions are hooks for developers to
+   *  implement the behavior they require from the time_get facet.
+  */
+  template<typename _CharT, typename _InIter>
+    class time_get : public locale::facet, public time_base
+    {
+    public:
+      // Types:
+      ///@{
+      /// Public typedefs
+      typedef _CharT			char_type;
+      typedef _InIter			iter_type;
+      ///@}
+
+      /// Numpunct facet id.
+      static locale::id			id;
+
+      /**
+       *  @brief  Constructor performs initialization.
+       *
+       *  This is the constructor provided by the standard.
+       *
+       *  @param __refs  Passed to the base facet class.
+      */
+      explicit
+      time_get(size_t __refs = 0)
+      : facet (__refs) { }
+
+      /**
+       *  @brief  Return preferred order of month, day, and year.
+       *
+       *  This function returns an enum from time_base::dateorder giving the
+       *  preferred ordering if the format @a x given to time_put::put() only
+       *  uses month, day, and year.  If the format @a x for the associated
+       *  locale uses other fields, this function returns
+       *  time_base::dateorder::noorder.
+       *
+       *  NOTE: The library always returns noorder at the moment.
+       *
+       *  @return  A member of time_base::dateorder.
+      */
+      dateorder
+      date_order()  const
+      { return this->do_date_order(); }
+
+      /**
+       *  @brief  Parse input time string.
+       *
+       *  This function parses a time according to the format @a X and puts the
+       *  results into a user-supplied struct tm.  The result is returned by
+       *  calling time_get::do_get_time().
+       *
+       *  If there is a valid time string according to format @a X, @a tm will
+       *  be filled in accordingly and the returned iterator will point to the
+       *  first character beyond the time string.  If an error occurs before
+       *  the end, err |= ios_base::failbit.  If parsing reads all the
+       *  characters, err |= ios_base::eofbit.
+       *
+       *  @param  __beg  Start of string to parse.
+       *  @param  __end  End of string to parse.
+       *  @param  __io  Source of the locale.
+       *  @param  __err  Error flags to set.
+       *  @param  __tm  Pointer to struct tm to fill in.
+       *  @return  Iterator to first char beyond time string.
+      */
+      iter_type
+      get_time(iter_type __beg, iter_type __end, ios_base& __io,
+	       ios_base::iostate& __err, tm* __tm)  const
+      { return this->do_get_time(__beg, __end, __io, __err, __tm); }
+
+      /**
+       *  @brief  Parse input date string.
+       *
+       *  This function parses a date according to the format @a x and puts the
+       *  results into a user-supplied struct tm.  The result is returned by
+       *  calling time_get::do_get_date().
+       *
+       *  If there is a valid date string according to format @a x, @a tm will
+       *  be filled in accordingly and the returned iterator will point to the
+       *  first character beyond the date string.  If an error occurs before
+       *  the end, err |= ios_base::failbit.  If parsing reads all the
+       *  characters, err |= ios_base::eofbit.
+       *
+       *  @param  __beg  Start of string to parse.
+       *  @param  __end  End of string to parse.
+       *  @param  __io  Source of the locale.
+       *  @param  __err  Error flags to set.
+       *  @param  __tm  Pointer to struct tm to fill in.
+       *  @return  Iterator to first char beyond date string.
+      */
+      iter_type
+      get_date(iter_type __beg, iter_type __end, ios_base& __io,
+	       ios_base::iostate& __err, tm* __tm)  const
+      { return this->do_get_date(__beg, __end, __io, __err, __tm); }
+
+      /**
+       *  @brief  Parse input weekday string.
+       *
+       *  This function parses a weekday name and puts the results into a
+       *  user-supplied struct tm.  The result is returned by calling
+       *  time_get::do_get_weekday().
+       *
+       *  Parsing starts by parsing an abbreviated weekday name.  If a valid
+       *  abbreviation is followed by a character that would lead to the full
+       *  weekday name, parsing continues until the full name is found or an
+       *  error occurs.  Otherwise parsing finishes at the end of the
+       *  abbreviated name.
+       *
+       *  If an error occurs before the end, err |= ios_base::failbit.  If
+       *  parsing reads all the characters, err |= ios_base::eofbit.
+       *
+       *  @param  __beg  Start of string to parse.
+       *  @param  __end  End of string to parse.
+       *  @param  __io  Source of the locale.
+       *  @param  __err  Error flags to set.
+       *  @param  __tm  Pointer to struct tm to fill in.
+       *  @return  Iterator to first char beyond weekday name.
+      */
+      iter_type
+      get_weekday(iter_type __beg, iter_type __end, ios_base& __io,
+		  ios_base::iostate& __err, tm* __tm) const
+      { return this->do_get_weekday(__beg, __end, __io, __err, __tm); }
+
+      /**
+       *  @brief  Parse input month string.
+       *
+       *  This function parses a month name and puts the results into a
+       *  user-supplied struct tm.  The result is returned by calling
+       *  time_get::do_get_monthname().
+       *
+       *  Parsing starts by parsing an abbreviated month name.  If a valid
+       *  abbreviation is followed by a character that would lead to the full
+       *  month name, parsing continues until the full name is found or an
+       *  error occurs.  Otherwise parsing finishes at the end of the
+       *  abbreviated name.
+       *
+       *  If an error occurs before the end, err |= ios_base::failbit.  If
+       *  parsing reads all the characters, err |=
+       *  ios_base::eofbit.
+       *
+       *  @param  __beg  Start of string to parse.
+       *  @param  __end  End of string to parse.
+       *  @param  __io  Source of the locale.
+       *  @param  __err  Error flags to set.
+       *  @param  __tm  Pointer to struct tm to fill in.
+       *  @return  Iterator to first char beyond month name.
+      */
+      iter_type
+      get_monthname(iter_type __beg, iter_type __end, ios_base& __io,
+		    ios_base::iostate& __err, tm* __tm) const
+      { return this->do_get_monthname(__beg, __end, __io, __err, __tm); }
+
+      /**
+       *  @brief  Parse input year string.
+       *
+       *  This function reads up to 4 characters to parse a year string and
+       *  puts the results into a user-supplied struct tm.  The result is
+       *  returned by calling time_get::do_get_year().
+       *
+       *  4 consecutive digits are interpreted as a full year.  If there are
+       *  exactly 2 consecutive digits, the library interprets this as the
+       *  number of years since 1900.
+       *
+       *  If an error occurs before the end, err |= ios_base::failbit.  If
+       *  parsing reads all the characters, err |= ios_base::eofbit.
+       *
+       *  @param  __beg  Start of string to parse.
+       *  @param  __end  End of string to parse.
+       *  @param  __io  Source of the locale.
+       *  @param  __err  Error flags to set.
+       *  @param  __tm  Pointer to struct tm to fill in.
+       *  @return  Iterator to first char beyond year.
+      */
+      iter_type
+      get_year(iter_type __beg, iter_type __end, ios_base& __io,
+	       ios_base::iostate& __err, tm* __tm) const
+      { return this->do_get_year(__beg, __end, __io, __err, __tm); }
+
+#if __cplusplus >= 201103L
+      /**
+       *  @brief  Parse input string according to format.
+       *
+       *  This function calls time_get::do_get with the provided
+       *  parameters.  @see do_get() and get().
+       *
+       *  @param __s        Start of string to parse.
+       *  @param __end      End of string to parse.
+       *  @param __io       Source of the locale.
+       *  @param __err      Error flags to set.
+       *  @param __tm       Pointer to struct tm to fill in.
+       *  @param __format   Format specifier.
+       *  @param __modifier Format modifier.
+       *  @return  Iterator to first char not parsed.
+       */
+      inline
+      iter_type get(iter_type __s, iter_type __end, ios_base& __io,
+                    ios_base::iostate& __err, tm* __tm, char __format,
+                    char __modifier = 0) const
+      {
+        return this->do_get(__s, __end, __io, __err, __tm, __format,
+                            __modifier);
+      }
+
+      /**
+       *  @brief  Parse input string according to format.
+       *
+       *  This function parses the input string according to a
+       *  provided format string.  It does the inverse of
+       *  time_put::put.  The format string follows the format
+       *  specified for strftime(3)/strptime(3).  The actual parsing
+       *  is done by time_get::do_get.
+       *
+       *  @param __s        Start of string to parse.
+       *  @param __end      End of string to parse.
+       *  @param __io       Source of the locale.
+       *  @param __err      Error flags to set.
+       *  @param __tm       Pointer to struct tm to fill in.
+       *  @param __fmt      Start of the format string.
+       *  @param __fmtend   End of the format string.
+       *  @return  Iterator to first char not parsed.
+       */
+      iter_type get(iter_type __s, iter_type __end, ios_base& __io,
+                    ios_base::iostate& __err, tm* __tm, const char_type* __fmt,
+                    const char_type* __fmtend) const;
+#endif // __cplusplus >= 201103L
+
+    protected:
+      /// Destructor.
+      virtual
+      ~time_get() { }
+
+      /**
+       *  @brief  Return preferred order of month, day, and year.
+       *
+       *  This function returns an enum from time_base::dateorder giving the
+       *  preferred ordering if the format @a x given to time_put::put() only
+       *  uses month, day, and year.  This function is a hook for derived
+       *  classes to change the value returned.
+       *
+       *  @return  A member of time_base::dateorder.
+      */
+      virtual dateorder
+      do_date_order() const;
+
+      /**
+       *  @brief  Parse input time string.
+       *
+       *  This function parses a time according to the format @a x and puts the
+       *  results into a user-supplied struct tm.  This function is a hook for
+       *  derived classes to change the value returned.  @see get_time() for
+       *  details.
+       *
+       *  @param  __beg  Start of string to parse.
+       *  @param  __end  End of string to parse.
+       *  @param  __io  Source of the locale.
+       *  @param  __err  Error flags to set.
+       *  @param  __tm  Pointer to struct tm to fill in.
+       *  @return  Iterator to first char beyond time string.
+      */
+      virtual iter_type
+      do_get_time(iter_type __beg, iter_type __end, ios_base& __io,
+		  ios_base::iostate& __err, tm* __tm) const;
+
+      /**
+       *  @brief  Parse input date string.
+       *
+       *  This function parses a date according to the format @a X and puts the
+       *  results into a user-supplied struct tm.  This function is a hook for
+       *  derived classes to change the value returned.  @see get_date() for
+       *  details.
+       *
+       *  @param  __beg  Start of string to parse.
+       *  @param  __end  End of string to parse.
+       *  @param  __io  Source of the locale.
+       *  @param  __err  Error flags to set.
+       *  @param  __tm  Pointer to struct tm to fill in.
+       *  @return  Iterator to first char beyond date string.
+      */
+      virtual iter_type
+      do_get_date(iter_type __beg, iter_type __end, ios_base& __io,
+		  ios_base::iostate& __err, tm* __tm) const;
+
+      /**
+       *  @brief  Parse input weekday string.
+       *
+       *  This function parses a weekday name and puts the results into a
+       *  user-supplied struct tm.  This function is a hook for derived
+       *  classes to change the value returned.  @see get_weekday() for
+       *  details.
+       *
+       *  @param  __beg  Start of string to parse.
+       *  @param  __end  End of string to parse.
+       *  @param  __io  Source of the locale.
+       *  @param  __err  Error flags to set.
+       *  @param  __tm  Pointer to struct tm to fill in.
+       *  @return  Iterator to first char beyond weekday name.
+      */
+      virtual iter_type
+      do_get_weekday(iter_type __beg, iter_type __end, ios_base&,
+		     ios_base::iostate& __err, tm* __tm) const;
+
+      /**
+       *  @brief  Parse input month string.
+       *
+       *  This function parses a month name and puts the results into a
+       *  user-supplied struct tm.  This function is a hook for derived
+       *  classes to change the value returned.  @see get_monthname() for
+       *  details.
+       *
+       *  @param  __beg  Start of string to parse.
+       *  @param  __end  End of string to parse.
+       *  @param  __io  Source of the locale.
+       *  @param  __err  Error flags to set.
+       *  @param  __tm  Pointer to struct tm to fill in.
+       *  @return  Iterator to first char beyond month name.
+      */
+      virtual iter_type
+      do_get_monthname(iter_type __beg, iter_type __end, ios_base&,
+		       ios_base::iostate& __err, tm* __tm) const;
+
+      /**
+       *  @brief  Parse input year string.
+       *
+       *  This function reads up to 4 characters to parse a year string and
+       *  puts the results into a user-supplied struct tm.  This function is a
+       *  hook for derived classes to change the value returned.  @see
+       *  get_year() for details.
+       *
+       *  @param  __beg  Start of string to parse.
+       *  @param  __end  End of string to parse.
+       *  @param  __io  Source of the locale.
+       *  @param  __err  Error flags to set.
+       *  @param  __tm  Pointer to struct tm to fill in.
+       *  @return  Iterator to first char beyond year.
+      */
+      virtual iter_type
+      do_get_year(iter_type __beg, iter_type __end, ios_base& __io,
+		  ios_base::iostate& __err, tm* __tm) const;
+
+#if __cplusplus >= 201103L
+      /**
+       *  @brief  Parse input string according to format.
+       *
+       *  This function parses the string according to the provided
+       *  format and optional modifier.  This function is a hook for
+       *  derived classes to change the value returned.  @see get()
+       *  for more details.
+       *
+       *  @param __s        Start of string to parse.
+       *  @param __end      End of string to parse.
+       *  @param __f        Source of the locale.
+       *  @param __err      Error flags to set.
+       *  @param __tm       Pointer to struct tm to fill in.
+       *  @param __format   Format specifier.
+       *  @param __modifier Format modifier.
+       *  @return  Iterator to first char not parsed.
+       */
+#if _GLIBCXX_USE_CXX11_ABI
+      virtual
+#endif
+      iter_type
+      do_get(iter_type __s, iter_type __end, ios_base& __f,
+             ios_base::iostate& __err, tm* __tm,
+             char __format, char __modifier) const;
+#endif // __cplusplus >= 201103L
+
+      // Extract numeric component of length __len.
+      iter_type
+      _M_extract_num(iter_type __beg, iter_type __end, int& __member,
+		     int __min, int __max, size_t __len,
+		     ios_base& __io, ios_base::iostate& __err) const;
+
+      // Extract any unique array of string literals in a const _CharT* array.
+      iter_type
+      _M_extract_name(iter_type __beg, iter_type __end, int& __member,
+		      const _CharT** __names, size_t __indexlen,
+		      ios_base& __io, ios_base::iostate& __err) const;
+
+      // Extract day or month name in a const _CharT* array.
+      iter_type
+      _M_extract_wday_or_month(iter_type __beg, iter_type __end, int& __member,
+			       const _CharT** __names, size_t __indexlen,
+			       ios_base& __io, ios_base::iostate& __err) const;
+
+      // Extract on a component-by-component basis, via __format argument.
+      iter_type
+      _M_extract_via_format(iter_type __beg, iter_type __end, ios_base& __io,
+			    ios_base::iostate& __err, tm* __tm,
+			    const _CharT* __format) const;
+
+      // Extract on a component-by-component basis, via __format argument, with
+      // state.
+      iter_type
+      _M_extract_via_format(iter_type __beg, iter_type __end, ios_base& __io,
+			    ios_base::iostate& __err, tm* __tm,
+			    const _CharT* __format,
+			    __time_get_state &__state) const;
+    };
+
+  template<typename _CharT, typename _InIter>
+    locale::id time_get<_CharT, _InIter>::id;
+
+  /// class time_get_byname [22.2.5.2].
+  template<typename _CharT, typename _InIter>
+    class time_get_byname : public time_get<_CharT, _InIter>
+    {
+    public:
+      // Types:
+      typedef _CharT			char_type;
+      typedef _InIter			iter_type;
+
+      explicit
+      time_get_byname(const char*, size_t __refs = 0)
+      : time_get<_CharT, _InIter>(__refs) { }
+
+#if __cplusplus >= 201103L
+      explicit
+      time_get_byname(const string& __s, size_t __refs = 0)
+      : time_get_byname(__s.c_str(), __refs) { }
+#endif
+
+    protected:
+      virtual
+      ~time_get_byname() { }
+    };
+
+_GLIBCXX_END_NAMESPACE_CXX11
+
+  /**
+   *  @brief  Primary class template time_put.
+   *  @ingroup locales
+   *
+   *  This facet encapsulates the code to format and output dates and times
+   *  according to formats used by strftime().
+   *
+   *  The time_put template uses protected virtual functions to provide the
+   *  actual results.  The public accessors forward the call to the virtual
+   *  functions.  These virtual functions are hooks for developers to
+   *  implement the behavior they require from the time_put facet.
+  */
+  template<typename _CharT, typename _OutIter>
+    class time_put : public locale::facet
+    {
+    public:
+      // Types:
+      ///@{
+      /// Public typedefs
+      typedef _CharT			char_type;
+      typedef _OutIter			iter_type;
+      ///@}
+
+      /// Numpunct facet id.
+      static locale::id			id;
+
+      /**
+       *  @brief  Constructor performs initialization.
+       *
+       *  This is the constructor provided by the standard.
+       *
+       *  @param __refs  Passed to the base facet class.
+      */
+      explicit
+      time_put(size_t __refs = 0)
+      : facet(__refs) { }
+
+      /**
+       *  @brief  Format and output a time or date.
+       *
+       *  This function formats the data in struct tm according to the
+       *  provided format string.  The format string is interpreted as by
+       *  strftime().
+       *
+       *  @param  __s  The stream to write to.
+       *  @param  __io  Source of locale.
+       *  @param  __fill  char_type to use for padding.
+       *  @param  __tm  Struct tm with date and time info to format.
+       *  @param  __beg  Start of format string.
+       *  @param  __end  End of format string.
+       *  @return  Iterator after writing.
+       */
+      iter_type
+      put(iter_type __s, ios_base& __io, char_type __fill, const tm* __tm,
+	  const _CharT* __beg, const _CharT* __end) const;
+
+      /**
+       *  @brief  Format and output a time or date.
+       *
+       *  This function formats the data in struct tm according to the
+       *  provided format char and optional modifier.  The format and modifier
+       *  are interpreted as by strftime().  It does so by returning
+       *  time_put::do_put().
+       *
+       *  @param  __s  The stream to write to.
+       *  @param  __io  Source of locale.
+       *  @param  __fill  char_type to use for padding.
+       *  @param  __tm  Struct tm with date and time info to format.
+       *  @param  __format  Format char.
+       *  @param  __mod  Optional modifier char.
+       *  @return  Iterator after writing.
+       */
+      iter_type
+      put(iter_type __s, ios_base& __io, char_type __fill,
+	  const tm* __tm, char __format, char __mod = 0) const
+      { return this->do_put(__s, __io, __fill, __tm, __format, __mod); }
+
+    protected:
+      /// Destructor.
+      virtual
+      ~time_put()
+      { }
+
+      /**
+       *  @brief  Format and output a time or date.
+       *
+       *  This function formats the data in struct tm according to the
+       *  provided format char and optional modifier.  This function is a hook
+       *  for derived classes to change the value returned.  @see put() for
+       *  more details.
+       *
+       *  @param  __s  The stream to write to.
+       *  @param  __io  Source of locale.
+       *  @param  __fill  char_type to use for padding.
+       *  @param  __tm  Struct tm with date and time info to format.
+       *  @param  __format  Format char.
+       *  @param  __mod  Optional modifier char.
+       *  @return  Iterator after writing.
+       */
+      virtual iter_type
+      do_put(iter_type __s, ios_base& __io, char_type __fill, const tm* __tm,
+	     char __format, char __mod) const;
+    };
+
+  template<typename _CharT, typename _OutIter>
+    locale::id time_put<_CharT, _OutIter>::id;
+
+  /// class time_put_byname [22.2.5.4].
+  template<typename _CharT, typename _OutIter>
+    class time_put_byname : public time_put<_CharT, _OutIter>
+    {
+    public:
+      // Types:
+      typedef _CharT			char_type;
+      typedef _OutIter			iter_type;
+
+      explicit
+      time_put_byname(const char*, size_t __refs = 0)
+      : time_put<_CharT, _OutIter>(__refs)
+      { }
+
+#if __cplusplus >= 201103L
+      explicit
+      time_put_byname(const string& __s, size_t __refs = 0)
+      : time_put_byname(__s.c_str(), __refs) { }
+#endif
+
+    protected:
+      virtual
+      ~time_put_byname() { }
+    };
+
+
+  /**
+   *  @brief  Money format ordering data.
+   *  @ingroup locales
+   *
+   *  This class contains an ordered array of 4 fields to represent the
+   *  pattern for formatting a money amount.  Each field may contain one entry
+   *  from the part enum.  symbol, sign, and value must be present and the
+   *  remaining field must contain either none or space.  @see
+   *  moneypunct::pos_format() and moneypunct::neg_format() for details of how
+   *  these fields are interpreted.
+  */
+  class money_base
+  {
+  public:
+    enum part { none, space, symbol, sign, value };
+    struct pattern { char field[4]; };
+
+    static const pattern _S_default_pattern;
+
+    enum
+    {
+      _S_minus,
+      _S_zero,
+      _S_end = 11
+    };
+
+    // String literal of acceptable (narrow) input/output, for
+    // money_get/money_put. "-0123456789"
+    static const char* _S_atoms;
+
+    // Construct and return valid pattern consisting of some combination of:
+    // space none symbol sign value
+    _GLIBCXX_CONST static pattern
+    _S_construct_pattern(char __precedes, char __space, char __posn) throw ();
+  };
+
+  template<typename _CharT, bool _Intl>
+    struct __moneypunct_cache : public locale::facet
+    {
+      const char*			_M_grouping;
+      size_t                            _M_grouping_size;
+      bool				_M_use_grouping;
+      _CharT				_M_decimal_point;
+      _CharT				_M_thousands_sep;
+      const _CharT*			_M_curr_symbol;
+      size_t                            _M_curr_symbol_size;
+      const _CharT*			_M_positive_sign;
+      size_t                            _M_positive_sign_size;
+      const _CharT*			_M_negative_sign;
+      size_t                            _M_negative_sign_size;
+      int				_M_frac_digits;
+      money_base::pattern		_M_pos_format;
+      money_base::pattern	        _M_neg_format;
+
+      // A list of valid numeric literals for input and output: in the standard
+      // "C" locale, this is "-0123456789". This array contains the chars after
+      // having been passed through the current locale's ctype<_CharT>.widen().
+      _CharT				_M_atoms[money_base::_S_end];
+
+      bool				_M_allocated;
+
+      __moneypunct_cache(size_t __refs = 0) : facet(__refs),
+      _M_grouping(0), _M_grouping_size(0), _M_use_grouping(false),
+      _M_decimal_point(_CharT()), _M_thousands_sep(_CharT()),
+      _M_curr_symbol(0), _M_curr_symbol_size(0),
+      _M_positive_sign(0), _M_positive_sign_size(0),
+      _M_negative_sign(0), _M_negative_sign_size(0),
+      _M_frac_digits(0),
+      _M_pos_format(money_base::pattern()),
+      _M_neg_format(money_base::pattern()), _M_allocated(false)
+      { }
+
+      ~__moneypunct_cache();
+
+      void
+      _M_cache(const locale& __loc);
+
+    private:
+      __moneypunct_cache&
+      operator=(const __moneypunct_cache&);
+      
+      explicit
+      __moneypunct_cache(const __moneypunct_cache&);
+    };
+
+  template<typename _CharT, bool _Intl>
+    __moneypunct_cache<_CharT, _Intl>::~__moneypunct_cache()
+    {
+      if (_M_allocated)
+	{
+	  delete [] _M_grouping;
+	  delete [] _M_curr_symbol;
+	  delete [] _M_positive_sign;
+	  delete [] _M_negative_sign;
+	}
+    }
+
+_GLIBCXX_BEGIN_NAMESPACE_CXX11
+
+  /**
+   *  @brief  Primary class template moneypunct.
+   *  @ingroup locales
+   *
+   *  This facet encapsulates the punctuation, grouping and other formatting
+   *  features of money amount string representations.
+  */
+  template<typename _CharT, bool _Intl>
+    class moneypunct : public locale::facet, public money_base
+    {
+    public:
+      // Types:
+      ///@{
+      /// Public typedefs
+      typedef _CharT			char_type;
+      typedef basic_string<_CharT>	string_type;
+      ///@}
+      typedef __moneypunct_cache<_CharT, _Intl>     __cache_type;
+
+    private:
+      __cache_type*			_M_data;
+
+    public:
+      /// This value is provided by the standard, but no reason for its
+      /// existence.
+      static const bool			intl = _Intl;
+      /// Numpunct facet id.
+      static locale::id			id;
+
+      /**
+       *  @brief  Constructor performs initialization.
+       *
+       *  This is the constructor provided by the standard.
+       *
+       *  @param __refs  Passed to the base facet class.
+      */
+      explicit
+      moneypunct(size_t __refs = 0)
+      : facet(__refs), _M_data(0)
+      { _M_initialize_moneypunct(); }
+
+      /**
+       *  @brief  Constructor performs initialization.
+       *
+       *  This is an internal constructor.
+       *
+       *  @param __cache  Cache for optimization.
+       *  @param __refs  Passed to the base facet class.
+      */
+      explicit
+      moneypunct(__cache_type* __cache, size_t __refs = 0)
+      : facet(__refs), _M_data(__cache)
+      { _M_initialize_moneypunct(); }
+
+      /**
+       *  @brief  Internal constructor. Not for general use.
+       *
+       *  This is a constructor for use by the library itself to set up new
+       *  locales.
+       *
+       *  @param __cloc  The C locale.
+       *  @param __s  The name of a locale.
+       *  @param __refs  Passed to the base facet class.
+      */
+      explicit
+      moneypunct(__c_locale __cloc, const char* __s, size_t __refs = 0)
+      : facet(__refs), _M_data(0)
+      { _M_initialize_moneypunct(__cloc, __s); }
+
+      /**
+       *  @brief  Return decimal point character.
+       *
+       *  This function returns a char_type to use as a decimal point.  It
+       *  does so by returning returning
+       *  moneypunct<char_type>::do_decimal_point().
+       *
+       *  @return  @a char_type representing a decimal point.
+      */
+      char_type
+      decimal_point() const
+      { return this->do_decimal_point(); }
+
+      /**
+       *  @brief  Return thousands separator character.
+       *
+       *  This function returns a char_type to use as a thousands
+       *  separator.  It does so by returning returning
+       *  moneypunct<char_type>::do_thousands_sep().
+       *
+       *  @return  char_type representing a thousands separator.
+      */
+      char_type
+      thousands_sep() const
+      { return this->do_thousands_sep(); }
+
+      /**
+       *  @brief  Return grouping specification.
+       *
+       *  This function returns a string representing groupings for the
+       *  integer part of an amount.  Groupings indicate where thousands
+       *  separators should be inserted.
+       *
+       *  Each char in the return string is interpret as an integer rather
+       *  than a character.  These numbers represent the number of digits in a
+       *  group.  The first char in the string represents the number of digits
+       *  in the least significant group.  If a char is negative, it indicates
+       *  an unlimited number of digits for the group.  If more chars from the
+       *  string are required to group a number, the last char is used
+       *  repeatedly.
+       *
+       *  For example, if the grouping() returns <code>\003\002</code>
+       *  and is applied to the number 123456789, this corresponds to
+       *  12,34,56,789.  Note that if the string was <code>32</code>, this would
+       *  put more than 50 digits into the least significant group if
+       *  the character set is ASCII.
+       *
+       *  The string is returned by calling
+       *  moneypunct<char_type>::do_grouping().
+       *
+       *  @return  string representing grouping specification.
+      */
+      string
+      grouping() const
+      { return this->do_grouping(); }
+
+      /**
+       *  @brief  Return currency symbol string.
+       *
+       *  This function returns a string_type to use as a currency symbol.  It
+       *  does so by returning returning
+       *  moneypunct<char_type>::do_curr_symbol().
+       *
+       *  @return  @a string_type representing a currency symbol.
+      */
+      string_type
+      curr_symbol() const
+      { return this->do_curr_symbol(); }
+
+      /**
+       *  @brief  Return positive sign string.
+       *
+       *  This function returns a string_type to use as a sign for positive
+       *  amounts.  It does so by returning returning
+       *  moneypunct<char_type>::do_positive_sign().
+       *
+       *  If the return value contains more than one character, the first
+       *  character appears in the position indicated by pos_format() and the
+       *  remainder appear at the end of the formatted string.
+       *
+       *  @return  @a string_type representing a positive sign.
+      */
+      string_type
+      positive_sign() const
+      { return this->do_positive_sign(); }
+
+      /**
+       *  @brief  Return negative sign string.
+       *
+       *  This function returns a string_type to use as a sign for negative
+       *  amounts.  It does so by returning returning
+       *  moneypunct<char_type>::do_negative_sign().
+       *
+       *  If the return value contains more than one character, the first
+       *  character appears in the position indicated by neg_format() and the
+       *  remainder appear at the end of the formatted string.
+       *
+       *  @return  @a string_type representing a negative sign.
+      */
+      string_type
+      negative_sign() const
+      { return this->do_negative_sign(); }
+
+      /**
+       *  @brief  Return number of digits in fraction.
+       *
+       *  This function returns the exact number of digits that make up the
+       *  fractional part of a money amount.  It does so by returning
+       *  returning moneypunct<char_type>::do_frac_digits().
+       *
+       *  The fractional part of a money amount is optional.  But if it is
+       *  present, there must be frac_digits() digits.
+       *
+       *  @return  Number of digits in amount fraction.
+      */
+      int
+      frac_digits() const
+      { return this->do_frac_digits(); }
+
+      ///@{
+      /**
+       *  @brief  Return pattern for money values.
+       *
+       *  This function returns a pattern describing the formatting of a
+       *  positive or negative valued money amount.  It does so by returning
+       *  returning moneypunct<char_type>::do_pos_format() or
+       *  moneypunct<char_type>::do_neg_format().
+       *
+       *  The pattern has 4 fields describing the ordering of symbol, sign,
+       *  value, and none or space.  There must be one of each in the pattern.
+       *  The none and space enums may not appear in the first field and space
+       *  may not appear in the final field.
+       *
+       *  The parts of a money string must appear in the order indicated by
+       *  the fields of the pattern.  The symbol field indicates that the
+       *  value of curr_symbol() may be present.  The sign field indicates
+       *  that the value of positive_sign() or negative_sign() must be
+       *  present.  The value field indicates that the absolute value of the
+       *  money amount is present.  none indicates 0 or more whitespace
+       *  characters, except at the end, where it permits no whitespace.
+       *  space indicates that 1 or more whitespace characters must be
+       *  present.
+       *
+       *  For example, for the US locale and pos_format() pattern
+       *  {symbol,sign,value,none}, curr_symbol() == &apos;$&apos;
+       *  positive_sign() == &apos;+&apos;, and value 10.01, and
+       *  options set to force the symbol, the corresponding string is
+       *  <code>$+10.01</code>.
+       *
+       *  @return  Pattern for money values.
+      */
+      pattern
+      pos_format() const
+      { return this->do_pos_format(); }
+
+      pattern
+      neg_format() const
+      { return this->do_neg_format(); }
+      ///@}
+
+    protected:
+      /// Destructor.
+      virtual
+      ~moneypunct();
+
+      /**
+       *  @brief  Return decimal point character.
+       *
+       *  Returns a char_type to use as a decimal point.  This function is a
+       *  hook for derived classes to change the value returned.
+       *
+       *  @return  @a char_type representing a decimal point.
+      */
+      virtual char_type
+      do_decimal_point() const
+      { return _M_data->_M_decimal_point; }
+
+      /**
+       *  @brief  Return thousands separator character.
+       *
+       *  Returns a char_type to use as a thousands separator.  This function
+       *  is a hook for derived classes to change the value returned.
+       *
+       *  @return  @a char_type representing a thousands separator.
+      */
+      virtual char_type
+      do_thousands_sep() const
+      { return _M_data->_M_thousands_sep; }
+
+      /**
+       *  @brief  Return grouping specification.
+       *
+       *  Returns a string representing groupings for the integer part of a
+       *  number.  This function is a hook for derived classes to change the
+       *  value returned.  @see grouping() for details.
+       *
+       *  @return  String representing grouping specification.
+      */
+      virtual string
+      do_grouping() const
+      { return _M_data->_M_grouping; }
+
+      /**
+       *  @brief  Return currency symbol string.
+       *
+       *  This function returns a string_type to use as a currency symbol.
+       *  This function is a hook for derived classes to change the value
+       *  returned.  @see curr_symbol() for details.
+       *
+       *  @return  @a string_type representing a currency symbol.
+      */
+      virtual string_type
+      do_curr_symbol()   const
+      { return _M_data->_M_curr_symbol; }
+
+      /**
+       *  @brief  Return positive sign string.
+       *
+       *  This function returns a string_type to use as a sign for positive
+       *  amounts.  This function is a hook for derived classes to change the
+       *  value returned.  @see positive_sign() for details.
+       *
+       *  @return  @a string_type representing a positive sign.
+      */
+      virtual string_type
+      do_positive_sign() const
+      { return _M_data->_M_positive_sign; }
+
+      /**
+       *  @brief  Return negative sign string.
+       *
+       *  This function returns a string_type to use as a sign for negative
+       *  amounts.  This function is a hook for derived classes to change the
+       *  value returned.  @see negative_sign() for details.
+       *
+       *  @return  @a string_type representing a negative sign.
+      */
+      virtual string_type
+      do_negative_sign() const
+      { return _M_data->_M_negative_sign; }
+
+      /**
+       *  @brief  Return number of digits in fraction.
+       *
+       *  This function returns the exact number of digits that make up the
+       *  fractional part of a money amount.  This function is a hook for
+       *  derived classes to change the value returned.  @see frac_digits()
+       *  for details.
+       *
+       *  @return  Number of digits in amount fraction.
+      */
+      virtual int
+      do_frac_digits() const
+      { return _M_data->_M_frac_digits; }
+
+      /**
+       *  @brief  Return pattern for money values.
+       *
+       *  This function returns a pattern describing the formatting of a
+       *  positive valued money amount.  This function is a hook for derived
+       *  classes to change the value returned.  @see pos_format() for
+       *  details.
+       *
+       *  @return  Pattern for money values.
+      */
+      virtual pattern
+      do_pos_format() const
+      { return _M_data->_M_pos_format; }
+
+      /**
+       *  @brief  Return pattern for money values.
+       *
+       *  This function returns a pattern describing the formatting of a
+       *  negative valued money amount.  This function is a hook for derived
+       *  classes to change the value returned.  @see neg_format() for
+       *  details.
+       *
+       *  @return  Pattern for money values.
+      */
+      virtual pattern
+      do_neg_format() const
+      { return _M_data->_M_neg_format; }
+
+      // For use at construction time only.
+       void
+       _M_initialize_moneypunct(__c_locale __cloc = 0,
+				const char* __name = 0);
+    };
+
+  template<typename _CharT, bool _Intl>
+    locale::id moneypunct<_CharT, _Intl>::id;
+
+  template<typename _CharT, bool _Intl>
+    const bool moneypunct<_CharT, _Intl>::intl;
+
+  template<>
+    moneypunct<char, true>::~moneypunct();
+
+  template<>
+    moneypunct<char, false>::~moneypunct();
+
+  template<>
+    void
+    moneypunct<char, true>::_M_initialize_moneypunct(__c_locale, const char*);
+
+  template<>
+    void
+    moneypunct<char, false>::_M_initialize_moneypunct(__c_locale, const char*);
+
+#ifdef _GLIBCXX_USE_WCHAR_T
+  template<>
+    moneypunct<wchar_t, true>::~moneypunct();
+
+  template<>
+    moneypunct<wchar_t, false>::~moneypunct();
+
+  template<>
+    void
+    moneypunct<wchar_t, true>::_M_initialize_moneypunct(__c_locale,
+							const char*);
+
+  template<>
+    void
+    moneypunct<wchar_t, false>::_M_initialize_moneypunct(__c_locale,
+							 const char*);
+#endif
+
+  /// class moneypunct_byname [22.2.6.4].
+  template<typename _CharT, bool _Intl>
+    class moneypunct_byname : public moneypunct<_CharT, _Intl>
+    {
+    public:
+      typedef _CharT			char_type;
+      typedef basic_string<_CharT>	string_type;
+
+      static const bool intl = _Intl;
+
+      explicit
+      moneypunct_byname(const char* __s, size_t __refs = 0)
+      : moneypunct<_CharT, _Intl>(__refs)
+      {
+	if (__builtin_strcmp(__s, "C") != 0
+	    && __builtin_strcmp(__s, "POSIX") != 0)
+	  {
+	    __c_locale __tmp;
+	    this->_S_create_c_locale(__tmp, __s);
+	    this->_M_initialize_moneypunct(__tmp);
+	    this->_S_destroy_c_locale(__tmp);
+	  }
+      }
+
+#if __cplusplus >= 201103L
+      explicit
+      moneypunct_byname(const string& __s, size_t __refs = 0)
+      : moneypunct_byname(__s.c_str(), __refs) { }
+#endif
+
+    protected:
+      virtual
+      ~moneypunct_byname() { }
+    };
+
+  template<typename _CharT, bool _Intl>
+    const bool moneypunct_byname<_CharT, _Intl>::intl;
+
+_GLIBCXX_END_NAMESPACE_CXX11
+
+_GLIBCXX_BEGIN_NAMESPACE_LDBL_OR_CXX11
+
+  /**
+   *  @brief  Primary class template money_get.
+   *  @ingroup locales
+   *
+   *  This facet encapsulates the code to parse and return a monetary
+   *  amount from a string.
+   *
+   *  The money_get template uses protected virtual functions to
+   *  provide the actual results.  The public accessors forward the
+   *  call to the virtual functions.  These virtual functions are
+   *  hooks for developers to implement the behavior they require from
+   *  the money_get facet.
+  */
+  template<typename _CharT, typename _InIter>
+    class money_get : public locale::facet
+    {
+    public:
+      // Types:
+      ///@{
+      /// Public typedefs
+      typedef _CharT			char_type;
+      typedef _InIter			iter_type;
+      typedef basic_string<_CharT>	string_type;
+      ///@}
+
+      /// Numpunct facet id.
+      static locale::id			id;
+
+      /**
+       *  @brief  Constructor performs initialization.
+       *
+       *  This is the constructor provided by the standard.
+       *
+       *  @param __refs  Passed to the base facet class.
+      */
+      explicit
+      money_get(size_t __refs = 0) : facet(__refs) { }
+
+      /**
+       *  @brief  Read and parse a monetary value.
+       *
+       *  This function reads characters from @a __s, interprets them as a
+       *  monetary value according to moneypunct and ctype facets retrieved
+       *  from io.getloc(), and returns the result in @a units as an integral
+       *  value moneypunct::frac_digits() * the actual amount.  For example,
+       *  the string $10.01 in a US locale would store 1001 in @a units.
+       *
+       *  Any characters not part of a valid money amount are not consumed.
+       *
+       *  If a money value cannot be parsed from the input stream, sets
+       *  err=(err|io.failbit).  If the stream is consumed before finishing
+       *  parsing,  sets err=(err|io.failbit|io.eofbit).  @a units is
+       *  unchanged if parsing fails.
+       *
+       *  This function works by returning the result of do_get().
+       *
+       *  @param  __s  Start of characters to parse.
+       *  @param  __end  End of characters to parse.
+       *  @param  __intl  Parameter to use_facet<moneypunct<CharT,intl> >.
+       *  @param  __io  Source of facets and io state.
+       *  @param  __err  Error field to set if parsing fails.
+       *  @param  __units  Place to store result of parsing.
+       *  @return  Iterator referencing first character beyond valid money
+       *	   amount.
+       */
+      iter_type
+      get(iter_type __s, iter_type __end, bool __intl, ios_base& __io,
+	  ios_base::iostate& __err, long double& __units) const
+      { return this->do_get(__s, __end, __intl, __io, __err, __units); }
+
+      /**
+       *  @brief  Read and parse a monetary value.
+       *
+       *  This function reads characters from @a __s, interprets them as
+       *  a monetary value according to moneypunct and ctype facets
+       *  retrieved from io.getloc(), and returns the result in @a
+       *  digits.  For example, the string $10.01 in a US locale would
+       *  store <code>1001</code> in @a digits.
+       *
+       *  Any characters not part of a valid money amount are not consumed.
+       *
+       *  If a money value cannot be parsed from the input stream, sets
+       *  err=(err|io.failbit).  If the stream is consumed before finishing
+       *  parsing,  sets err=(err|io.failbit|io.eofbit).
+       *
+       *  This function works by returning the result of do_get().
+       *
+       *  @param  __s  Start of characters to parse.
+       *  @param  __end  End of characters to parse.
+       *  @param  __intl  Parameter to use_facet<moneypunct<CharT,intl> >.
+       *  @param  __io  Source of facets and io state.
+       *  @param  __err  Error field to set if parsing fails.
+       *  @param  __digits  Place to store result of parsing.
+       *  @return  Iterator referencing first character beyond valid money
+       *	   amount.
+       */
+      iter_type
+      get(iter_type __s, iter_type __end, bool __intl, ios_base& __io,
+	  ios_base::iostate& __err, string_type& __digits) const
+      { return this->do_get(__s, __end, __intl, __io, __err, __digits); }
+
+    protected:
+      /// Destructor.
+      virtual
+      ~money_get() { }
+
+      /**
+       *  @brief  Read and parse a monetary value.
+       *
+       *  This function reads and parses characters representing a monetary
+       *  value.  This function is a hook for derived classes to change the
+       *  value returned.  @see get() for details.
+       */
+      // XXX GLIBCXX_ABI Deprecated
+#if defined _GLIBCXX_LONG_DOUBLE_COMPAT && defined __LONG_DOUBLE_128__ \
+      && (_GLIBCXX_USE_CXX11_ABI == 0 || defined __LONG_DOUBLE_IEEE128__)
+      virtual iter_type
+      __do_get(iter_type __s, iter_type __end, bool __intl, ios_base& __io,
+	       ios_base::iostate& __err, double& __units) const;
+#else
+      virtual iter_type
+      do_get(iter_type __s, iter_type __end, bool __intl, ios_base& __io,
+	     ios_base::iostate& __err, long double& __units) const;
+#endif
+
+      /**
+       *  @brief  Read and parse a monetary value.
+       *
+       *  This function reads and parses characters representing a monetary
+       *  value.  This function is a hook for derived classes to change the
+       *  value returned.  @see get() for details.
+       */
+      virtual iter_type
+      do_get(iter_type __s, iter_type __end, bool __intl, ios_base& __io,
+	     ios_base::iostate& __err, string_type& __digits) const;
+
+      // XXX GLIBCXX_ABI Deprecated
+#if defined _GLIBCXX_LONG_DOUBLE_ALT128_COMPAT \
+      && defined __LONG_DOUBLE_IEEE128__
+      virtual iter_type
+      __do_get(iter_type __s, iter_type __end, bool __intl, ios_base& __io,
+	       ios_base::iostate& __err, __ibm128& __units) const;
+#endif
+
+      // XXX GLIBCXX_ABI Deprecated
+#if defined _GLIBCXX_LONG_DOUBLE_COMPAT && defined __LONG_DOUBLE_128__ \
+      && (_GLIBCXX_USE_CXX11_ABI == 0 || defined __LONG_DOUBLE_IEEE128__)
+      virtual iter_type
+      do_get(iter_type __s, iter_type __end, bool __intl, ios_base& __io,
+	     ios_base::iostate& __err, long double& __units) const;
+#endif
+
+      template<bool _Intl>
+        iter_type
+        _M_extract(iter_type __s, iter_type __end, ios_base& __io,
+		   ios_base::iostate& __err, string& __digits) const;     
+    };
+
+  template<typename _CharT, typename _InIter>
+    locale::id money_get<_CharT, _InIter>::id;
+
+  /**
+   *  @brief  Primary class template money_put.
+   *  @ingroup locales
+   *
+   *  This facet encapsulates the code to format and output a monetary
+   *  amount.
+   *
+   *  The money_put template uses protected virtual functions to
+   *  provide the actual results.  The public accessors forward the
+   *  call to the virtual functions.  These virtual functions are
+   *  hooks for developers to implement the behavior they require from
+   *  the money_put facet.
+  */
+  template<typename _CharT, typename _OutIter>
+    class money_put : public locale::facet
+    {
+    public:
+      ///@{
+      /// Public typedefs
+      typedef _CharT			char_type;
+      typedef _OutIter			iter_type;
+      typedef basic_string<_CharT>	string_type;
+      ///@}
+
+      /// Numpunct facet id.
+      static locale::id			id;
+
+      /**
+       *  @brief  Constructor performs initialization.
+       *
+       *  This is the constructor provided by the standard.
+       *
+       *  @param __refs  Passed to the base facet class.
+      */
+      explicit
+      money_put(size_t __refs = 0) : facet(__refs) { }
+
+      /**
+       *  @brief  Format and output a monetary value.
+       *
+       *  This function formats @a units as a monetary value according to
+       *  moneypunct and ctype facets retrieved from io.getloc(), and writes
+       *  the resulting characters to @a __s.  For example, the value 1001 in a
+       *  US locale would write <code>$10.01</code> to @a __s.
+       *
+       *  This function works by returning the result of do_put().
+       *
+       *  @param  __s  The stream to write to.
+       *  @param  __intl  Parameter to use_facet<moneypunct<CharT,intl> >.
+       *  @param  __io  Source of facets and io state.
+       *  @param  __fill  char_type to use for padding.
+       *  @param  __units  Place to store result of parsing.
+       *  @return  Iterator after writing.
+       */
+      iter_type
+      put(iter_type __s, bool __intl, ios_base& __io,
+	  char_type __fill, long double __units) const
+      { return this->do_put(__s, __intl, __io, __fill, __units); }
+
+      /**
+       *  @brief  Format and output a monetary value.
+       *
+       *  This function formats @a digits as a monetary value
+       *  according to moneypunct and ctype facets retrieved from
+       *  io.getloc(), and writes the resulting characters to @a __s.
+       *  For example, the string <code>1001</code> in a US locale
+       *  would write <code>$10.01</code> to @a __s.
+       *
+       *  This function works by returning the result of do_put().
+       *
+       *  @param  __s  The stream to write to.
+       *  @param  __intl  Parameter to use_facet<moneypunct<CharT,intl> >.
+       *  @param  __io  Source of facets and io state.
+       *  @param  __fill  char_type to use for padding.
+       *  @param  __digits  Place to store result of parsing.
+       *  @return  Iterator after writing.
+       */
+      iter_type
+      put(iter_type __s, bool __intl, ios_base& __io,
+	  char_type __fill, const string_type& __digits) const
+      { return this->do_put(__s, __intl, __io, __fill, __digits); }
+
+    protected:
+      /// Destructor.
+      virtual
+      ~money_put() { }
+
+      /**
+       *  @brief  Format and output a monetary value.
+       *
+       *  This function formats @a units as a monetary value according to
+       *  moneypunct and ctype facets retrieved from io.getloc(), and writes
+       *  the resulting characters to @a __s.  For example, the value 1001 in a
+       *  US locale would write <code>$10.01</code> to @a __s.
+       *
+       *  This function is a hook for derived classes to change the value
+       *  returned.  @see put().
+       *
+       *  @param  __s  The stream to write to.
+       *  @param  __intl  Parameter to use_facet<moneypunct<CharT,intl> >.
+       *  @param  __io  Source of facets and io state.
+       *  @param  __fill  char_type to use for padding.
+       *  @param  __units  Place to store result of parsing.
+       *  @return  Iterator after writing.
+       */
+      // XXX GLIBCXX_ABI Deprecated
+#if defined _GLIBCXX_LONG_DOUBLE_COMPAT && defined __LONG_DOUBLE_128__ \
+      && (_GLIBCXX_USE_CXX11_ABI == 0 || defined __LONG_DOUBLE_IEEE128__)
+      virtual iter_type
+      __do_put(iter_type __s, bool __intl, ios_base& __io, char_type __fill,
+	       double __units) const;
+#else
+      virtual iter_type
+      do_put(iter_type __s, bool __intl, ios_base& __io, char_type __fill,
+	     long double __units) const;
+#endif
+
+      /**
+       *  @brief  Format and output a monetary value.
+       *
+       *  This function formats @a digits as a monetary value
+       *  according to moneypunct and ctype facets retrieved from
+       *  io.getloc(), and writes the resulting characters to @a __s.
+       *  For example, the string <code>1001</code> in a US locale
+       *  would write <code>$10.01</code> to @a __s.
+       *
+       *  This function is a hook for derived classes to change the value
+       *  returned.  @see put().
+       *
+       *  @param  __s  The stream to write to.
+       *  @param  __intl  Parameter to use_facet<moneypunct<CharT,intl> >.
+       *  @param  __io  Source of facets and io state.
+       *  @param  __fill  char_type to use for padding.
+       *  @param  __digits  Place to store result of parsing.
+       *  @return  Iterator after writing.
+       */
+      virtual iter_type
+      do_put(iter_type __s, bool __intl, ios_base& __io, char_type __fill,
+	     const string_type& __digits) const;
+
+      // XXX GLIBCXX_ABI Deprecated
+#if defined _GLIBCXX_LONG_DOUBLE_ALT128_COMPAT \
+      && defined __LONG_DOUBLE_IEEE128__
+      virtual iter_type
+      __do_put(iter_type __s, bool __intl, ios_base& __io, char_type __fill,
+	       __ibm128 __units) const;
+#endif
+
+      // XXX GLIBCXX_ABI Deprecated
+#if defined _GLIBCXX_LONG_DOUBLE_COMPAT && defined __LONG_DOUBLE_128__ \
+      && (_GLIBCXX_USE_CXX11_ABI == 0 || defined __LONG_DOUBLE_IEEE128__)
+      virtual iter_type
+      do_put(iter_type __s, bool __intl, ios_base& __io, char_type __fill,
+	     long double __units) const;
+#endif
+
+      template<bool _Intl>
+        iter_type
+        _M_insert(iter_type __s, ios_base& __io, char_type __fill,
+		  const string_type& __digits) const;
+    };
+
+  template<typename _CharT, typename _OutIter>
+    locale::id money_put<_CharT, _OutIter>::id;
+
+_GLIBCXX_END_NAMESPACE_LDBL_OR_CXX11
+
+  /**
+   *  @brief  Messages facet base class providing catalog typedef.
+   *  @ingroup locales
+   */
+  struct messages_base
+  {
+    typedef int catalog;
+  };
+
+_GLIBCXX_BEGIN_NAMESPACE_CXX11
+
+  /**
+   *  @brief  Primary class template messages.
+   *  @ingroup locales
+   *
+   *  This facet encapsulates the code to retrieve messages from
+   *  message catalogs.  The only thing defined by the standard for this facet
+   *  is the interface.  All underlying functionality is
+   *  implementation-defined.
+   *
+   *  This library currently implements 3 versions of the message facet.  The
+   *  first version (gnu) is a wrapper around gettext, provided by libintl.
+   *  The second version (ieee) is a wrapper around catgets.  The final
+   *  version (default) does no actual translation.  These implementations are
+   *  only provided for char and wchar_t instantiations.
+   *
+   *  The messages template uses protected virtual functions to
+   *  provide the actual results.  The public accessors forward the
+   *  call to the virtual functions.  These virtual functions are
+   *  hooks for developers to implement the behavior they require from
+   *  the messages facet.
+  */
+  template<typename _CharT>
+    class messages : public locale::facet, public messages_base
+    {
+    public:
+      // Types:
+      ///@{
+      /// Public typedefs
+      typedef _CharT			char_type;
+      typedef basic_string<_CharT>	string_type;
+      ///@}
+
+    protected:
+      // Underlying "C" library locale information saved from
+      // initialization, needed by messages_byname as well.
+      __c_locale			_M_c_locale_messages;
+      const char*			_M_name_messages;
+
+    public:
+      /// Numpunct facet id.
+      static locale::id			id;
+
+      /**
+       *  @brief  Constructor performs initialization.
+       *
+       *  This is the constructor provided by the standard.
+       *
+       *  @param __refs  Passed to the base facet class.
+      */
+      explicit
+      messages(size_t __refs = 0);
+
+      // Non-standard.
+      /**
+       *  @brief  Internal constructor.  Not for general use.
+       *
+       *  This is a constructor for use by the library itself to set up new
+       *  locales.
+       *
+       *  @param  __cloc  The C locale.
+       *  @param  __s  The name of a locale.
+       *  @param  __refs  Refcount to pass to the base class.
+       */
+      explicit
+      messages(__c_locale __cloc, const char* __s, size_t __refs = 0);
+
+      /*
+       *  @brief  Open a message catalog.
+       *
+       *  This function opens and returns a handle to a message catalog by
+       *  returning do_open(__s, __loc).
+       *
+       *  @param  __s  The catalog to open.
+       *  @param  __loc  Locale to use for character set conversions.
+       *  @return  Handle to the catalog or value < 0 if open fails.
+      */
+      catalog
+      open(const basic_string<char>& __s, const locale& __loc) const
+      { return this->do_open(__s, __loc); }
+
+      // Non-standard and unorthodox, yet effective.
+      /*
+       *  @brief  Open a message catalog.
+       *
+       *  This non-standard function opens and returns a handle to a message
+       *  catalog by returning do_open(s, loc).  The third argument provides a
+       *  message catalog root directory for gnu gettext and is ignored
+       *  otherwise.
+       *
+       *  @param  __s  The catalog to open.
+       *  @param  __loc  Locale to use for character set conversions.
+       *  @param  __dir  Message catalog root directory.
+       *  @return  Handle to the catalog or value < 0 if open fails.
+      */
+      catalog
+      open(const basic_string<char>&, const locale&, const char*) const;
+
+      /*
+       *  @brief  Look up a string in a message catalog.
+       *
+       *  This function retrieves and returns a message from a catalog by
+       *  returning do_get(c, set, msgid, s).
+       *
+       *  For gnu, @a __set and @a msgid are ignored.  Returns gettext(s).
+       *  For default, returns s. For ieee, returns catgets(c,set,msgid,s).
+       *
+       *  @param  __c  The catalog to access.
+       *  @param  __set  Implementation-defined.
+       *  @param  __msgid  Implementation-defined.
+       *  @param  __s  Default return value if retrieval fails.
+       *  @return  Retrieved message or @a __s if get fails.
+      */
+      string_type
+      get(catalog __c, int __set, int __msgid, const string_type& __s) const
+      { return this->do_get(__c, __set, __msgid, __s); }
+
+      /*
+       *  @brief  Close a message catalog.
+       *
+       *  Closes catalog @a c by calling do_close(c).
+       *
+       *  @param  __c  The catalog to close.
+      */
+      void
+      close(catalog __c) const
+      { return this->do_close(__c); }
+
+    protected:
+      /// Destructor.
+      virtual
+      ~messages();
+
+      /*
+       *  @brief  Open a message catalog.
+       *
+       *  This function opens and returns a handle to a message catalog in an
+       *  implementation-defined manner.  This function is a hook for derived
+       *  classes to change the value returned.
+       *
+       *  @param  __s  The catalog to open.
+       *  @param  __loc  Locale to use for character set conversions.
+       *  @return  Handle to the opened catalog, value < 0 if open failed.
+      */
+      virtual catalog
+      do_open(const basic_string<char>&, const locale&) const;
+
+      /*
+       *  @brief  Look up a string in a message catalog.
+       *
+       *  This function retrieves and returns a message from a catalog in an
+       *  implementation-defined manner.  This function is a hook for derived
+       *  classes to change the value returned.
+       *
+       *  For gnu, @a __set and @a __msgid are ignored.  Returns gettext(s).
+       *  For default, returns s. For ieee, returns catgets(c,set,msgid,s).
+       *
+       *  @param  __c  The catalog to access.
+       *  @param  __set  Implementation-defined.
+       *  @param  __msgid  Implementation-defined.
+       *  @param  __s  Default return value if retrieval fails.
+       *  @return  Retrieved message or @a __s if get fails.
+      */
+      virtual string_type
+      do_get(catalog, int, int, const string_type& __dfault) const;
+
+      /*
+       *  @brief  Close a message catalog.
+       *
+       *  @param  __c  The catalog to close.
+      */
+      virtual void
+      do_close(catalog) const;
+
+      // Returns a locale and codeset-converted string, given a char* message.
+      char*
+      _M_convert_to_char(const string_type& __msg) const
+      {
+	// XXX
+	return reinterpret_cast<char*>(const_cast<_CharT*>(__msg.c_str()));
+      }
+
+      // Returns a locale and codeset-converted string, given a char* message.
+      string_type
+      _M_convert_from_char(char*) const
+      {
+	// XXX
+	return string_type();
+      }
+     };
+
+  template<typename _CharT>
+    locale::id messages<_CharT>::id;
+
+  /// Specializations for required instantiations.
+  template<>
+    string
+    messages<char>::do_get(catalog, int, int, const string&) const;
+
+#ifdef _GLIBCXX_USE_WCHAR_T
+  template<>
+    wstring
+    messages<wchar_t>::do_get(catalog, int, int, const wstring&) const;
+#endif
+
+   /// class messages_byname [22.2.7.2].
+   template<typename _CharT>
+    class messages_byname : public messages<_CharT>
+    {
+    public:
+      typedef _CharT			char_type;
+      typedef basic_string<_CharT>	string_type;
+
+      explicit
+      messages_byname(const char* __s, size_t __refs = 0);
+
+#if __cplusplus >= 201103L
+      explicit
+      messages_byname(const string& __s, size_t __refs = 0)
+      : messages_byname(__s.c_str(), __refs) { }
+#endif
+
+    protected:
+      virtual
+      ~messages_byname()
+      { }
+    };
+
+_GLIBCXX_END_NAMESPACE_CXX11
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+// Include host and configuration specific messages functions.
+#include <bits/messages_members.h>
+
+// 22.2.1.5  Template class codecvt
+#include <bits/codecvt.h>
+
+#include <bits/locale_facets_nonio.tcc>
+
+#endif
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@@ -0,0 +1,1834 @@
+// Locale support -*- C++ -*-
+
+// Copyright (C) 2007-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/locale_facets_nonio.tcc
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{locale}
+ */
+
+#ifndef _LOCALE_FACETS_NONIO_TCC
+#define _LOCALE_FACETS_NONIO_TCC 1
+
+#pragma GCC system_header
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  template<typename _CharT, bool _Intl>
+    struct __use_cache<__moneypunct_cache<_CharT, _Intl> >
+    {
+      const __moneypunct_cache<_CharT, _Intl>*
+      operator() (const locale& __loc) const
+      {
+	const size_t __i = moneypunct<_CharT, _Intl>::id._M_id();
+	const locale::facet** __caches = __loc._M_impl->_M_caches;
+	if (!__caches[__i])
+	  {
+	    __moneypunct_cache<_CharT, _Intl>* __tmp = 0;
+	    __try
+	      {
+		__tmp = new __moneypunct_cache<_CharT, _Intl>;
+		__tmp->_M_cache(__loc);
+	      }
+	    __catch(...)
+	      {
+		delete __tmp;
+		__throw_exception_again;
+	      }
+	    __loc._M_impl->_M_install_cache(__tmp, __i);
+	  }
+	return static_cast<
+	  const __moneypunct_cache<_CharT, _Intl>*>(__caches[__i]);
+      }
+    };
+
+  template<typename _CharT, bool _Intl>
+    void
+    __moneypunct_cache<_CharT, _Intl>::_M_cache(const locale& __loc)
+    {
+      const moneypunct<_CharT, _Intl>& __mp =
+	use_facet<moneypunct<_CharT, _Intl> >(__loc);
+
+      struct _Scoped_str
+      {
+	size_t _M_len;
+	_CharT* _M_str;
+
+	explicit
+	_Scoped_str(const basic_string<_CharT>& __str)
+	: _M_len(__str.size()), _M_str(new _CharT[_M_len])
+	{ __str.copy(_M_str, _M_len); }
+
+	~_Scoped_str() { delete[] _M_str; }
+
+	void
+	_M_release(const _CharT*& __p, size_t& __n)
+	{
+	  __p = _M_str;
+	  __n = _M_len;
+	  _M_str = 0;
+	}
+      };
+
+      _Scoped_str __curr_symbol(__mp.curr_symbol());
+      _Scoped_str __positive_sign(__mp.positive_sign());
+      _Scoped_str __negative_sign(__mp.negative_sign());
+
+      const string& __g = __mp.grouping();
+      const size_t __g_size = __g.size();
+      char* const __grouping = new char[__g_size];
+      __g.copy(__grouping, __g_size);
+
+      // All allocations succeeded without throwing, OK to modify *this now.
+
+      _M_grouping = __grouping;
+      _M_grouping_size = __g_size;
+      _M_use_grouping = (__g_size
+			 && static_cast<signed char>(__grouping[0]) > 0
+			 && (__grouping[0]
+			     != __gnu_cxx::__numeric_traits<char>::__max));
+
+      _M_decimal_point = __mp.decimal_point();
+      _M_thousands_sep = __mp.thousands_sep();
+
+      __curr_symbol._M_release(_M_curr_symbol, _M_curr_symbol_size);
+      __positive_sign._M_release(_M_positive_sign, _M_positive_sign_size);
+      __negative_sign._M_release(_M_negative_sign, _M_negative_sign_size);
+
+      _M_frac_digits = __mp.frac_digits();
+      _M_pos_format = __mp.pos_format();
+      _M_neg_format = __mp.neg_format();
+
+      const ctype<_CharT>& __ct = use_facet<ctype<_CharT> >(__loc);
+      __ct.widen(money_base::_S_atoms,
+		 money_base::_S_atoms + money_base::_S_end, _M_atoms);
+
+      _M_allocated = true;
+    }
+
+_GLIBCXX_BEGIN_NAMESPACE_LDBL_OR_CXX11
+
+  template<typename _CharT, typename _InIter>
+    template<bool _Intl>
+      _InIter
+      money_get<_CharT, _InIter>::
+      _M_extract(iter_type __beg, iter_type __end, ios_base& __io,
+		 ios_base::iostate& __err, string& __units) const
+      {
+	typedef char_traits<_CharT>			  __traits_type;
+	typedef typename string_type::size_type	          size_type;	
+	typedef money_base::part			  part;
+	typedef __moneypunct_cache<_CharT, _Intl>         __cache_type;
+	
+	const locale& __loc = __io._M_getloc();
+	const ctype<_CharT>& __ctype = use_facet<ctype<_CharT> >(__loc);
+
+	__use_cache<__cache_type> __uc;
+	const __cache_type* __lc = __uc(__loc);
+	const char_type* __lit = __lc->_M_atoms;
+
+	// Deduced sign.
+	bool __negative = false;
+	// Sign size.
+	size_type __sign_size = 0;
+	// True if sign is mandatory.
+	const bool __mandatory_sign = (__lc->_M_positive_sign_size
+				       && __lc->_M_negative_sign_size);
+	// String of grouping info from thousands_sep plucked from __units.
+	string __grouping_tmp;
+	if (__lc->_M_use_grouping)
+	  __grouping_tmp.reserve(32);
+	// Last position before the decimal point.
+	int __last_pos = 0;
+	// Separator positions, then, possibly, fractional digits.
+	int __n = 0;
+	// If input iterator is in a valid state.
+	bool __testvalid = true;
+	// Flag marking when a decimal point is found.
+	bool __testdecfound = false;
+
+	// The tentative returned string is stored here.
+	string __res;
+	__res.reserve(32);
+
+	const char_type* __lit_zero = __lit + money_base::_S_zero;
+	const money_base::pattern __p = __lc->_M_neg_format;
+	for (int __i = 0; __i < 4 && __testvalid; ++__i)
+	  {
+	    const part __which = static_cast<part>(__p.field[__i]);
+	    switch (__which)
+	      {
+	      case money_base::symbol:
+		// According to 22.2.6.1.2, p2, symbol is required
+		// if (__io.flags() & ios_base::showbase), otherwise
+		// is optional and consumed only if other characters
+		// are needed to complete the format.
+		if (__io.flags() & ios_base::showbase || __sign_size > 1
+		    || __i == 0
+		    || (__i == 1 && (__mandatory_sign
+				     || (static_cast<part>(__p.field[0])
+					 == money_base::sign)
+				     || (static_cast<part>(__p.field[2])
+					 == money_base::space)))
+		    || (__i == 2 && ((static_cast<part>(__p.field[3])
+				      == money_base::value)
+				     || (__mandatory_sign
+					 && (static_cast<part>(__p.field[3])
+					     == money_base::sign)))))
+		  {
+		    const size_type __len = __lc->_M_curr_symbol_size;
+		    size_type __j = 0;
+		    for (; __beg != __end && __j < __len
+			   && *__beg == __lc->_M_curr_symbol[__j];
+			 ++__beg, (void)++__j);
+		    if (__j != __len
+			&& (__j || __io.flags() & ios_base::showbase))
+		      __testvalid = false;
+		  }
+		break;
+	      case money_base::sign:
+		// Sign might not exist, or be more than one character long.
+		if (__lc->_M_positive_sign_size && __beg != __end
+		    && *__beg == __lc->_M_positive_sign[0])
+		  {
+		    __sign_size = __lc->_M_positive_sign_size;
+		    ++__beg;
+		  }
+		else if (__lc->_M_negative_sign_size && __beg != __end
+			 && *__beg == __lc->_M_negative_sign[0])
+		  {
+		    __negative = true;
+		    __sign_size = __lc->_M_negative_sign_size;
+		    ++__beg;
+		  }
+		else if (__lc->_M_positive_sign_size
+			 && !__lc->_M_negative_sign_size)
+		  // "... if no sign is detected, the result is given the sign
+		  // that corresponds to the source of the empty string"
+		  __negative = true;
+		else if (__mandatory_sign)
+		  __testvalid = false;
+		break;
+	      case money_base::value:
+		// Extract digits, remove and stash away the
+		// grouping of found thousands separators.
+		for (; __beg != __end; ++__beg)
+		  {
+		    const char_type __c = *__beg;
+		    const char_type* __q = __traits_type::find(__lit_zero, 
+							       10, __c);
+		    if (__q != 0)
+		      {
+			__res += money_base::_S_atoms[__q - __lit];
+			++__n;
+		      }
+		    else if (__c == __lc->_M_decimal_point 
+			     && !__testdecfound)
+		      {
+			if (__lc->_M_frac_digits <= 0)
+			  break;
+
+			__last_pos = __n;
+			__n = 0;
+			__testdecfound = true;
+		      }
+		    else if (__lc->_M_use_grouping
+			     && __c == __lc->_M_thousands_sep
+			     && !__testdecfound)
+		      {
+			if (__n)
+			  {
+			    // Mark position for later analysis.
+			    __grouping_tmp += static_cast<char>(__n);
+			    __n = 0;
+			  }
+			else
+			  {
+			    __testvalid = false;
+			    break;
+			  }
+		      }
+		    else
+		      break;
+		  }
+		if (__res.empty())
+		  __testvalid = false;
+		break;
+	      case money_base::space:
+		// At least one space is required.
+		if (__beg != __end && __ctype.is(ctype_base::space, *__beg))
+		  ++__beg;
+		else
+		  __testvalid = false;
+		// fallthrough
+	      case money_base::none:
+		// Only if not at the end of the pattern.
+		if (__i != 3)
+		  for (; __beg != __end
+			 && __ctype.is(ctype_base::space, *__beg); ++__beg);
+		break;
+	      }
+	  }
+
+	// Need to get the rest of the sign characters, if they exist.
+	if (__sign_size > 1 && __testvalid)
+	  {
+	    const char_type* __sign = __negative ? __lc->_M_negative_sign
+	                                         : __lc->_M_positive_sign;
+	    size_type __i = 1;
+	    for (; __beg != __end && __i < __sign_size
+		   && *__beg == __sign[__i]; ++__beg, (void)++__i);
+	    
+	    if (__i != __sign_size)
+	      __testvalid = false;
+	  }
+
+	if (__testvalid)
+	  {
+	    // Strip leading zeros.
+	    if (__res.size() > 1)
+	      {
+		const size_type __first = __res.find_first_not_of('0');
+		const bool __only_zeros = __first == string::npos;
+		if (__first)
+		  __res.erase(0, __only_zeros ? __res.size() - 1 : __first);
+	      }
+
+	    // 22.2.6.1.2, p4
+	    if (__negative && __res[0] != '0')
+	      __res.insert(__res.begin(), '-');
+	    
+	    // Test for grouping fidelity.
+	    if (__grouping_tmp.size())
+	      {
+		// Add the ending grouping.
+		__grouping_tmp += static_cast<char>(__testdecfound ? __last_pos
+						                   : __n);
+		if (!std::__verify_grouping(__lc->_M_grouping,
+					    __lc->_M_grouping_size,
+					    __grouping_tmp))
+		  __err |= ios_base::failbit;
+	      }
+	    
+	    // Iff not enough digits were supplied after the decimal-point.
+	    if (__testdecfound && __n != __lc->_M_frac_digits)
+	      __testvalid = false;
+	  }
+
+	// Iff valid sequence is not recognized.
+	if (!__testvalid)
+	  __err |= ios_base::failbit;
+	else
+	  __units.swap(__res);
+	
+	// Iff no more characters are available.
+	if (__beg == __end)
+	  __err |= ios_base::eofbit;
+	return __beg;
+      }
+
+#if defined _GLIBCXX_LONG_DOUBLE_COMPAT && defined __LONG_DOUBLE_128__ \
+      && (_GLIBCXX_USE_CXX11_ABI == 0 || defined __LONG_DOUBLE_IEEE128__)
+  template<typename _CharT, typename _InIter>
+    _InIter
+    money_get<_CharT, _InIter>::
+    __do_get(iter_type __beg, iter_type __end, bool __intl, ios_base& __io,
+	     ios_base::iostate& __err, double& __units) const
+    {
+      string __str;
+      __beg = __intl ? _M_extract<true>(__beg, __end, __io, __err, __str)
+                     : _M_extract<false>(__beg, __end, __io, __err, __str);
+      std::__convert_to_v(__str.c_str(), __units, __err, _S_get_c_locale());
+      return __beg;
+    }
+#endif
+
+  template<typename _CharT, typename _InIter>
+    _InIter
+    money_get<_CharT, _InIter>::
+    do_get(iter_type __beg, iter_type __end, bool __intl, ios_base& __io,
+	   ios_base::iostate& __err, long double& __units) const
+    {
+      string __str;
+      __beg = __intl ? _M_extract<true>(__beg, __end, __io, __err, __str)
+	             : _M_extract<false>(__beg, __end, __io, __err, __str);
+      std::__convert_to_v(__str.c_str(), __units, __err, _S_get_c_locale());
+      return __beg;
+    }
+
+  template<typename _CharT, typename _InIter>
+    _InIter
+    money_get<_CharT, _InIter>::
+    do_get(iter_type __beg, iter_type __end, bool __intl, ios_base& __io,
+	   ios_base::iostate& __err, string_type& __digits) const
+    {
+      typedef typename string::size_type                  size_type;
+
+      const locale& __loc = __io._M_getloc();
+      const ctype<_CharT>& __ctype = use_facet<ctype<_CharT> >(__loc);
+
+      string __str;
+      __beg = __intl ? _M_extract<true>(__beg, __end, __io, __err, __str)
+	             : _M_extract<false>(__beg, __end, __io, __err, __str);
+      const size_type __len = __str.size();
+      if (__len)
+	{
+	  __digits.resize(__len);
+	  __ctype.widen(__str.data(), __str.data() + __len, &__digits[0]);
+	}
+      return __beg;
+    }
+
+#if defined _GLIBCXX_LONG_DOUBLE_ALT128_COMPAT \
+      && defined __LONG_DOUBLE_IEEE128__
+  template<typename _CharT, typename _InIter>
+    _InIter
+    money_get<_CharT, _InIter>::
+    __do_get(iter_type __beg, iter_type __end, bool __intl, ios_base& __io,
+	     ios_base::iostate& __err, __ibm128& __units) const
+    {
+      string __str;
+      __beg = __intl ? _M_extract<true>(__beg, __end, __io, __err, __str)
+	             : _M_extract<false>(__beg, __end, __io, __err, __str);
+      std::__convert_to_v(__str.c_str(), __units, __err, _S_get_c_locale());
+      return __beg;
+    }
+#endif
+
+  template<typename _CharT, typename _OutIter>
+    template<bool _Intl>
+      _OutIter
+      money_put<_CharT, _OutIter>::
+      _M_insert(iter_type __s, ios_base& __io, char_type __fill,
+		const string_type& __digits) const
+      {
+	typedef typename string_type::size_type	          size_type;
+	typedef money_base::part                          part;
+	typedef __moneypunct_cache<_CharT, _Intl>         __cache_type;
+      
+	const locale& __loc = __io._M_getloc();
+	const ctype<_CharT>& __ctype = use_facet<ctype<_CharT> >(__loc);
+
+	__use_cache<__cache_type> __uc;
+	const __cache_type* __lc = __uc(__loc);
+	const char_type* __lit = __lc->_M_atoms;
+
+	// Determine if negative or positive formats are to be used, and
+	// discard leading negative_sign if it is present.
+	const char_type* __beg = __digits.data();
+
+	money_base::pattern __p;
+	const char_type* __sign;
+	size_type __sign_size;
+	if (!(*__beg == __lit[money_base::_S_minus]))
+	  {
+	    __p = __lc->_M_pos_format;
+	    __sign = __lc->_M_positive_sign;
+	    __sign_size = __lc->_M_positive_sign_size;
+	  }
+	else
+	  {
+	    __p = __lc->_M_neg_format;
+	    __sign = __lc->_M_negative_sign;
+	    __sign_size = __lc->_M_negative_sign_size;
+	    if (__digits.size())
+	      ++__beg;
+	  }
+       
+	// Look for valid numbers in the ctype facet within input digits.
+	size_type __len = __ctype.scan_not(ctype_base::digit, __beg,
+					   __beg + __digits.size()) - __beg;
+	if (__len)
+	  {
+	    // Assume valid input, and attempt to format.
+	    // Break down input numbers into base components, as follows:
+	    //   final_value = grouped units + (decimal point) + (digits)
+	    string_type __value;
+	    __value.reserve(2 * __len);
+
+	    // Add thousands separators to non-decimal digits, per
+	    // grouping rules.
+	    long __paddec = __len - __lc->_M_frac_digits;
+	    if (__paddec > 0)
+	      {
+		if (__lc->_M_frac_digits < 0)
+		  __paddec = __len;
+		if (__lc->_M_grouping_size)
+		  {
+		    __value.assign(2 * __paddec, char_type());
+		    _CharT* __vend =
+		      std::__add_grouping(&__value[0], __lc->_M_thousands_sep,
+					  __lc->_M_grouping,
+					  __lc->_M_grouping_size,
+					  __beg, __beg + __paddec);
+		    __value.erase(__vend - &__value[0]);
+		  }
+		else
+		  __value.assign(__beg, __paddec);
+	      }
+
+	    // Deal with decimal point, decimal digits.
+	    if (__lc->_M_frac_digits > 0)
+	      {
+		__value += __lc->_M_decimal_point;
+		if (__paddec >= 0)
+		  __value.append(__beg + __paddec, __lc->_M_frac_digits);
+		else
+		  {
+		    // Have to pad zeros in the decimal position.
+		    __value.append(-__paddec, __lit[money_base::_S_zero]);
+		    __value.append(__beg, __len);
+		  }
+	      }
+  
+	    // Calculate length of resulting string.
+	    const ios_base::fmtflags __f = __io.flags() 
+	                                   & ios_base::adjustfield;
+	    __len = __value.size() + __sign_size;
+	    __len += ((__io.flags() & ios_base::showbase)
+		      ? __lc->_M_curr_symbol_size : 0);
+
+	    string_type __res;
+	    __res.reserve(2 * __len);
+	    
+	    const size_type __width = static_cast<size_type>(__io.width());  
+	    const bool __testipad = (__f == ios_base::internal
+				     && __len < __width);
+	    // Fit formatted digits into the required pattern.
+	    for (int __i = 0; __i < 4; ++__i)
+	      {
+		const part __which = static_cast<part>(__p.field[__i]);
+		switch (__which)
+		  {
+		  case money_base::symbol:
+		    if (__io.flags() & ios_base::showbase)
+		      __res.append(__lc->_M_curr_symbol,
+				   __lc->_M_curr_symbol_size);
+		    break;
+		  case money_base::sign:
+		    // Sign might not exist, or be more than one
+		    // character long. In that case, add in the rest
+		    // below.
+		    if (__sign_size)
+		      __res += __sign[0];
+		    break;
+		  case money_base::value:
+		    __res += __value;
+		    break;
+		  case money_base::space:
+		    // At least one space is required, but if internal
+		    // formatting is required, an arbitrary number of
+		    // fill spaces will be necessary.
+		    if (__testipad)
+		      __res.append(__width - __len, __fill);
+		    else
+		      __res += __fill;
+		    break;
+		  case money_base::none:
+		    if (__testipad)
+		      __res.append(__width - __len, __fill);
+		    break;
+		  }
+	      }
+	    
+	    // Special case of multi-part sign parts.
+	    if (__sign_size > 1)
+	      __res.append(__sign + 1, __sign_size - 1);
+	    
+	    // Pad, if still necessary.
+	    __len = __res.size();
+	    if (__width > __len)
+	      {
+		if (__f == ios_base::left)
+		  // After.
+		  __res.append(__width - __len, __fill);
+		else
+		  // Before.
+		  __res.insert(0, __width - __len, __fill);
+		__len = __width;
+	      }
+	    
+	    // Write resulting, fully-formatted string to output iterator.
+	    __s = std::__write(__s, __res.data(), __len);
+	  }
+	__io.width(0);
+	return __s;    
+      }
+
+#if defined _GLIBCXX_LONG_DOUBLE_COMPAT && defined __LONG_DOUBLE_128__ \
+      && (_GLIBCXX_USE_CXX11_ABI == 0 || defined __LONG_DOUBLE_IEEE128__)
+  template<typename _CharT, typename _OutIter>
+    _OutIter
+    money_put<_CharT, _OutIter>::
+    __do_put(iter_type __s, bool __intl, ios_base& __io, char_type __fill,
+	     double __units) const
+    { return this->do_put(__s, __intl, __io, __fill, (long double) __units); }
+#endif
+
+  template<typename _CharT, typename _OutIter>
+    _OutIter
+    money_put<_CharT, _OutIter>::
+    do_put(iter_type __s, bool __intl, ios_base& __io, char_type __fill,
+	   long double __units) const
+    {
+      const locale __loc = __io.getloc();
+      const ctype<_CharT>& __ctype = use_facet<ctype<_CharT> >(__loc);
+#if _GLIBCXX_USE_C99_STDIO
+      // First try a buffer perhaps big enough.
+      int __cs_size = 64;
+      char* __cs = static_cast<char*>(__builtin_alloca(__cs_size));
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 328. Bad sprintf format modifier in money_put<>::do_put()
+      int __len = std::__convert_from_v(_S_get_c_locale(), __cs, __cs_size,
+					"%.*Lf", 0, __units);
+      // If the buffer was not large enough, try again with the correct size.
+      if (__len >= __cs_size)
+	{
+	  __cs_size = __len + 1;
+	  __cs = static_cast<char*>(__builtin_alloca(__cs_size));
+	  __len = std::__convert_from_v(_S_get_c_locale(), __cs, __cs_size,
+					"%.*Lf", 0, __units);
+	}
+#else
+      // max_exponent10 + 1 for the integer part, + 2 for sign and '\0'.
+      const int __cs_size =
+	__gnu_cxx::__numeric_traits<long double>::__max_exponent10 + 3;
+      char* __cs = static_cast<char*>(__builtin_alloca(__cs_size));
+      int __len = std::__convert_from_v(_S_get_c_locale(), __cs, 0, "%.*Lf", 
+					0, __units);
+#endif
+      string_type __digits(__len, char_type());
+      __ctype.widen(__cs, __cs + __len, &__digits[0]);
+      return __intl ? _M_insert<true>(__s, __io, __fill, __digits)
+	            : _M_insert<false>(__s, __io, __fill, __digits);
+    }
+
+  template<typename _CharT, typename _OutIter>
+    _OutIter
+    money_put<_CharT, _OutIter>::
+    do_put(iter_type __s, bool __intl, ios_base& __io, char_type __fill,
+	   const string_type& __digits) const
+    { return __intl ? _M_insert<true>(__s, __io, __fill, __digits)
+	            : _M_insert<false>(__s, __io, __fill, __digits); }
+
+#if defined _GLIBCXX_LONG_DOUBLE_ALT128_COMPAT \
+      && defined __LONG_DOUBLE_IEEE128__
+extern "C"
+__typeof__(__builtin_snprintf) __glibcxx_snprintfibm128 __asm__("snprintf");
+
+  template<typename _CharT, typename _OutIter>
+    _OutIter
+    money_put<_CharT, _OutIter>::
+    __do_put(iter_type __s, bool __intl, ios_base& __io, char_type __fill,
+	     __ibm128 __units) const
+    {
+      const locale __loc = __io.getloc();
+      const ctype<_CharT>& __ctype = use_facet<ctype<_CharT> >(__loc);
+      // First try a buffer perhaps big enough.
+      int __cs_size = 64;
+      char* __cs = static_cast<char*>(__builtin_alloca(__cs_size));
+      const __c_locale __old = __gnu_cxx::__uselocale(_S_get_c_locale());
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 328. Bad sprintf format modifier in money_put<>::do_put()
+      int __len = __glibcxx_snprintfibm128(__cs, __cs_size, "%.*Lf", 0,
+					     __units);
+      // If the buffer was not large enough, try again with the correct size.
+      if (__len >= __cs_size)
+	{
+	  __cs_size = __len + 1;
+	  __cs = static_cast<char*>(__builtin_alloca(__cs_size));
+	  __len = __glibcxx_snprintfibm128(__cs, __cs_size, "%.*Lf", 0,
+					     __units);
+	}
+      __gnu_cxx::__uselocale(__old);
+      string_type __digits(__len, char_type());
+      __ctype.widen(__cs, __cs + __len, &__digits[0]);
+      return __intl ? _M_insert<true>(__s, __io, __fill, __digits)
+	            : _M_insert<false>(__s, __io, __fill, __digits);
+    }
+#endif
+
+_GLIBCXX_END_NAMESPACE_LDBL_OR_CXX11
+
+  // NB: Not especially useful. Without an ios_base object or some
+  // kind of locale reference, we are left clawing at the air where
+  // the side of the mountain used to be...
+  template<typename _CharT, typename _InIter>
+    time_base::dateorder
+    time_get<_CharT, _InIter>::do_date_order() const
+    { return time_base::no_order; }
+
+  // Expand a strptime format string and parse it.  E.g., do_get_date() may
+  // pass %m/%d/%Y => extracted characters.
+  template<typename _CharT, typename _InIter>
+    _InIter
+    time_get<_CharT, _InIter>::
+    _M_extract_via_format(iter_type __beg, iter_type __end, ios_base& __io,
+			  ios_base::iostate& __err, tm* __tm,
+			  const _CharT* __format,
+			  __time_get_state &__state) const
+    {
+      const locale& __loc = __io._M_getloc();
+      const __timepunct<_CharT>& __tp = use_facet<__timepunct<_CharT> >(__loc);
+      const ctype<_CharT>& __ctype = use_facet<ctype<_CharT> >(__loc);
+      const size_t __len = char_traits<_CharT>::length(__format);
+
+      ios_base::iostate __tmperr = ios_base::goodbit;
+      size_t __i = 0;
+      for (; __beg != __end && __i < __len && !__tmperr; ++__i)
+	{
+	  if (__ctype.narrow(__format[__i], 0) == '%')
+	    {
+	      // Verify valid formatting code, attempt to extract.
+	      char __c = __ctype.narrow(__format[++__i], 0);
+	      int __mem = 0;
+	      if (__c == 'E' || __c == 'O')
+		__c = __ctype.narrow(__format[++__i], 0);
+	      switch (__c)
+		{
+		  const char* __cs;
+		  _CharT __wcs[10];
+		case 'a':
+		case 'A':
+		  // Weekday name (possibly abbreviated) [tm_wday]
+		  const char_type*  __days[14];
+		  __tp._M_days(&__days[0]);
+		  __tp._M_days_abbreviated(&__days[7]);
+		  __beg = _M_extract_name(__beg, __end, __mem, __days,
+					  14, __io, __tmperr);
+		  if (!__tmperr)
+		    {
+		      __tm->tm_wday = __mem % 7;
+		      __state._M_have_wday = 1;
+		    }
+		  break;
+		case 'h':
+		case 'b':
+		case 'B':
+		  // Month name (possibly abbreviated) [tm_mon]
+		  const char_type*  __months[24];
+		  __tp._M_months(&__months[0]);
+		  __tp._M_months_abbreviated(&__months[12]);
+		  __beg = _M_extract_name(__beg, __end, __mem,
+					  __months, 24, __io, __tmperr);
+		  if (!__tmperr)
+		    {
+		      __tm->tm_mon = __mem % 12;
+		      __state._M_have_mon = 1;
+		      __state._M_want_xday = 1;
+		    }
+		  break;
+		case 'c':
+		  // Default time and date representation.
+		  const char_type*  __dt[2];
+		  __tp._M_date_time_formats(__dt);
+		  __beg = _M_extract_via_format(__beg, __end, __io, __tmperr, 
+						__tm, __dt[0], __state);
+		  if (!__tmperr)
+		    __state._M_want_xday = 1;
+		  break;
+		case 'C':
+		  // Century.
+		  __beg = _M_extract_num(__beg, __end, __mem, 0, 99, 2,
+					 __io, __tmperr);
+		  if (!__tmperr)
+		    {
+		      __state._M_century = __mem;
+		      __state._M_have_century = 1;
+		      __state._M_want_xday = 1;
+		    }
+		  break;
+		case 'd':
+		case 'e':
+		  // Day [1, 31]. [tm_mday]
+		  if (__ctype.is(ctype_base::space, *__beg))
+		    ++__beg;
+		  __beg = _M_extract_num(__beg, __end, __mem, 1, 31, 2,
+					 __io, __tmperr);
+		  if (!__tmperr)
+		    {
+		      __tm->tm_mday = __mem;
+		      __state._M_have_mday = 1;
+		      __state._M_want_xday = 1;
+		    }
+		  break;
+		case 'D':
+		  // Equivalent to %m/%d/%y.[tm_mon, tm_mday, tm_year]
+		  __cs = "%m/%d/%y";
+		  __ctype.widen(__cs, __cs + 9, __wcs);
+		  __beg = _M_extract_via_format(__beg, __end, __io, __tmperr, 
+						__tm, __wcs, __state);
+		  if (!__tmperr)
+		    __state._M_want_xday = 1;
+		  break;
+		case 'H':
+		  // Hour [00, 23]. [tm_hour]
+		  __beg = _M_extract_num(__beg, __end, __mem, 0, 23, 2,
+					 __io, __tmperr);
+		  if (!__tmperr)
+		    {
+		      __tm->tm_hour = __mem;
+		      __state._M_have_I = 0;
+		    }
+		  break;
+		case 'I':
+		  // Hour [01, 12]. [tm_hour]
+		  __beg = _M_extract_num(__beg, __end, __mem, 1, 12, 2,
+					 __io, __tmperr);
+		  if (!__tmperr)
+		    {
+		      __tm->tm_hour = __mem % 12;
+		      __state._M_have_I = 1;
+		    }
+		  break;
+		case 'j':
+		  // Day number of year.
+		  __beg = _M_extract_num(__beg, __end, __mem, 1, 366, 3,
+					 __io, __tmperr);
+		  if (!__tmperr)
+		    {
+		      __tm->tm_yday = __mem - 1;
+		      __state._M_have_yday = 1;
+		    }
+		  break;
+		case 'm':
+		  // Month [01, 12]. [tm_mon]
+		  __beg = _M_extract_num(__beg, __end, __mem, 1, 12, 2, 
+					 __io, __tmperr);
+		  if (!__tmperr)
+		    {
+		      __tm->tm_mon = __mem - 1;
+		      __state._M_have_mon = 1;
+		    }
+		  break;
+		case 'M':
+		  // Minute [00, 59]. [tm_min]
+		  __beg = _M_extract_num(__beg, __end, __mem, 0, 59, 2,
+					 __io, __tmperr);
+		  if (!__tmperr)
+		    __tm->tm_min = __mem;
+		  break;
+		case 'n':
+		case 't':
+		  while (__beg != __end
+			 && __ctype.is(ctype_base::space, *__beg))
+		    ++__beg;
+		  break;
+		case 'p':
+		  // Locale's a.m. or p.m.
+		  const char_type*  __ampm[2];
+		  __tp._M_am_pm(&__ampm[0]);
+		  if (!__ampm[0][0] || !__ampm[1][0])
+		    break;
+		  __beg = _M_extract_name(__beg, __end, __mem, __ampm,
+					  2, __io, __tmperr);
+		  if (!__tmperr && __mem)
+		    __state._M_is_pm = 1;
+		  break;
+		case 'r':
+		  // Locale's 12-hour clock time format (in C %I:%M:%S %p).
+		  const char_type*  __ampm_format;
+		  __tp._M_am_pm_format(&__ampm_format);
+		  __beg = _M_extract_via_format(__beg, __end, __io, __tmperr,
+						__tm, __ampm_format, __state);
+		  break;
+		case 'R':
+		  // Equivalent to (%H:%M).
+		  __cs = "%H:%M";
+		  __ctype.widen(__cs, __cs + 6, __wcs);
+		  __beg = _M_extract_via_format(__beg, __end, __io, __tmperr, 
+						__tm, __wcs, __state);
+		  break;
+		case 'S':
+		  // Seconds. [tm_sec]
+		  // [00, 60] in C99 (one leap-second), [00, 61] in C89.
+#if _GLIBCXX_USE_C99
+		  __beg = _M_extract_num(__beg, __end, __mem, 0, 60, 2,
+#else
+		  __beg = _M_extract_num(__beg, __end, __mem, 0, 61, 2,
+#endif
+					 __io, __tmperr);
+		  if (!__tmperr)
+		    __tm->tm_sec = __mem;
+		  break;
+		case 'T':
+		  // Equivalent to (%H:%M:%S).
+		  __cs = "%H:%M:%S";
+		  __ctype.widen(__cs, __cs + 9, __wcs);
+		  __beg = _M_extract_via_format(__beg, __end, __io, __tmperr, 
+						__tm, __wcs, __state);
+		  break;
+		case 'U':
+		  // Week number of the year (Sunday as first day of week).
+		  __beg = _M_extract_num(__beg, __end, __mem, 0, 53, 2,
+					 __io, __tmperr);
+		  if (!__tmperr)
+		    {
+		      __state._M_week_no = __mem;
+		      __state._M_have_uweek = 1;
+		    }
+		  break;
+		case 'w':
+		  // Weekday [tm_wday]
+		  __beg = _M_extract_num(__beg, __end, __mem, 0, 6, 1,
+					 __io, __tmperr);
+		  if (!__tmperr)
+		    {
+		      __tm->tm_wday = __mem;
+		      __state._M_have_wday = 1;
+		    }
+		  break;
+		case 'W':
+		  // Week number of the year (Monday as first day of week).
+		  __beg = _M_extract_num(__beg, __end, __mem, 0, 53, 2,
+					 __io, __tmperr);
+		  if (!__tmperr)
+		    {
+		      __state._M_week_no = __mem;
+		      __state._M_have_wweek = 1;
+		    }
+		  break;
+		case 'x':
+		  // Locale's date.
+		  const char_type*  __dates[2];
+		  __tp._M_date_formats(__dates);
+		  __beg = _M_extract_via_format(__beg, __end, __io, __tmperr, 
+						__tm, __dates[0], __state);
+		  break;
+		case 'X':
+		  // Locale's time.
+		  const char_type*  __times[2];
+		  __tp._M_time_formats(__times);
+		  __beg = _M_extract_via_format(__beg, __end, __io, __tmperr, 
+						__tm, __times[0], __state);
+		  break;
+		case 'y':
+		  // The last 2 digits of year.
+		  __beg = _M_extract_num(__beg, __end, __mem, 0, 99, 2,
+					 __io, __tmperr);
+		  if (!__tmperr)
+		    {
+		      __state._M_want_century = 1;
+		      __state._M_want_xday = 1;
+		      // As an extension, if the 2 digits are followed by
+		      // 1-2 further digits, treat it like %Y.
+		      __c = 0;
+		      if (__beg != __end)
+			__c = __ctype.narrow(*__beg, '*');
+		      if (__c >= '0' && __c <= '9')
+			{
+			  ++__beg;
+			  __mem = __mem * 10 + (__c - '0');
+			  if (__beg != __end)
+			    {
+			      __c = __ctype.narrow(*__beg, '*');
+			      if (__c >= '0' && __c <= '9')
+				{
+				  ++__beg;
+				  __mem = __mem * 10 + (__c - '0');
+				}
+			    }
+			  __mem -= 1900;
+			  __state._M_want_century = 0;
+			}
+		      // Otherwise, as per POSIX 2008, 00-68 is 2000-2068,
+		      // while 69-99 is 1969-1999.
+		      else if (__mem < 69)
+			__mem += 100;
+		      __tm->tm_year = __mem;
+		    }
+		  break;
+		case 'Y':
+		  // Year.
+		  __beg = _M_extract_num(__beg, __end, __mem, 0, 9999, 4,
+					 __io, __tmperr);
+		  if (!__tmperr)
+		    {
+		      __tm->tm_year = __mem - 1900;
+		      __state._M_want_century = 0;
+		      __state._M_want_xday = 1;
+		    }
+		  break;
+		case 'Z':
+		  // Timezone info.
+		  if (__ctype.is(ctype_base::upper, *__beg))
+		    {
+		      int __tmp;
+		      __beg = _M_extract_name(__beg, __end, __tmp,
+				       __timepunct_cache<_CharT>::_S_timezones,
+					      14, __io, __tmperr);
+
+		      // GMT requires special effort.
+		      if (__beg != __end && !__tmperr && __tmp == 0
+			  && (*__beg == __ctype.widen('-')
+			      || *__beg == __ctype.widen('+')))
+			{
+			  __beg = _M_extract_num(__beg, __end, __tmp, 0, 23, 2,
+						 __io, __tmperr);
+			  __beg = _M_extract_num(__beg, __end, __tmp, 0, 59, 2,
+						 __io, __tmperr);
+			}
+		    }
+		  else
+		    __tmperr |= ios_base::failbit;
+		  break;
+		case '%':
+		  if (*__beg == __ctype.widen('%'))
+		    ++__beg;
+		  else
+		    __tmperr |= ios_base::failbit;
+		  break;
+		default:
+		  // Not recognized.
+		  __tmperr |= ios_base::failbit;
+		}
+	    }
+	  else if (__ctype.is(ctype_base::space, __format[__i]))
+	    {
+	      // Skip any whitespace.
+	      while (__beg != __end
+		     && __ctype.is(ctype_base::space, *__beg))
+		++__beg;
+	    }
+	  else
+	    {
+	      // Verify format and input match, extract and discard.
+	      // TODO real case-insensitive comparison
+	      if (__ctype.tolower(__format[__i]) == __ctype.tolower(*__beg)
+		  || __ctype.toupper(__format[__i]) == __ctype.toupper(*__beg))
+		++__beg;
+	      else
+		__tmperr |= ios_base::failbit;
+	    }
+	}
+
+      if (__tmperr || __i != __len)
+	__err |= ios_base::failbit;
+  
+      return __beg;
+    }
+
+  template<typename _CharT, typename _InIter>
+    _InIter
+    time_get<_CharT, _InIter>::
+    _M_extract_via_format(iter_type __beg, iter_type __end, ios_base& __io,
+			  ios_base::iostate& __err, tm* __tm,
+			  const _CharT* __format) const
+    {
+      __time_get_state __state = __time_get_state();
+      return _M_extract_via_format(__beg, __end, __io, __err, __tm,
+				   __format, __state);
+    }
+
+  template<typename _CharT, typename _InIter>
+    _InIter
+    time_get<_CharT, _InIter>::
+    _M_extract_num(iter_type __beg, iter_type __end, int& __member,
+		   int __min, int __max, size_t __len,
+		   ios_base& __io, ios_base::iostate& __err) const
+    {
+      const locale& __loc = __io._M_getloc();
+      const ctype<_CharT>& __ctype = use_facet<ctype<_CharT> >(__loc);
+
+      size_t __i = 0;
+      int __value = 0;
+      for (; __beg != __end && __i < __len; ++__beg, (void)++__i)
+	{
+	  const char __c = __ctype.narrow(*__beg, '*');
+	  if (__c >= '0' && __c <= '9')
+	    {
+	      __value = __value * 10 + (__c - '0');
+	      if (__value > __max)
+		break;
+	    }
+	  else
+	    break;
+	}
+      if (__i && __value >= __min && __value <= __max)
+	__member = __value;
+      else
+	__err |= ios_base::failbit;
+
+      return __beg;
+    }
+
+  // Assumptions:
+  // All elements in __names are unique, except if __indexlen is
+  // even __names in the first half could be the same as corresponding
+  // __names in the second half (May is abbreviated as May).  Some __names
+  // elements could be prefixes of other __names elements.
+  template<typename _CharT, typename _InIter>
+    _InIter
+    time_get<_CharT, _InIter>::
+    _M_extract_name(iter_type __beg, iter_type __end, int& __member,
+		    const _CharT** __names, size_t __indexlen,
+		    ios_base& __io, ios_base::iostate& __err) const
+    {
+      typedef char_traits<_CharT>		__traits_type;
+      const locale& __loc = __io._M_getloc();
+      const ctype<_CharT>& __ctype = use_facet<ctype<_CharT> >(__loc);
+
+      size_t* __matches
+	= static_cast<size_t*>(__builtin_alloca(2 * sizeof(size_t)
+						* __indexlen));
+      size_t* __lengths = __matches + __indexlen;
+      size_t __nmatches = 0;
+      size_t __pos = 0;
+      bool __testvalid = true;
+      const char_type* __name;
+      bool __begupdated = false;
+
+      // Look for initial matches.
+      if (__beg != __end)
+	{
+	  const char_type __c = *__beg;
+	  // TODO real case-insensitive comparison
+	  const char_type __cl = __ctype.tolower(__c);
+	  const char_type __cu = __ctype.toupper(__c);
+	  for (size_t __i1 = 0; __i1 < __indexlen; ++__i1)
+	    if (__cl == __ctype.tolower(__names[__i1][0])
+		|| __cu == __ctype.toupper(__names[__i1][0]))
+	      {
+		__lengths[__nmatches]
+		  = __traits_type::length(__names[__i1]);
+		__matches[__nmatches++] = __i1;
+	      }
+	}
+
+      while (__nmatches > 1)
+	{
+	  // Find smallest matching string.
+	  size_t __minlen = __lengths[0];
+	  for (size_t __i2 = 1; __i2 < __nmatches; ++__i2)
+	    __minlen = std::min(__minlen, __lengths[__i2]);
+	  ++__pos;
+	  ++__beg;
+	  if (__pos == __minlen)
+	    {
+	      // If some match has remaining length of 0,
+	      // need to decide if any match with remaining
+	      // length non-zero matches the next character.
+	      // If so, remove all matches with remaining length
+	      // 0 from consideration, otherwise keep only matches
+	      // with remaining length 0.
+	      bool __match_longer = false;
+
+	      if (__beg != __end)
+		{
+		  // TODO real case-insensitive comparison
+		  const char_type __cl = __ctype.tolower(*__beg);
+		  const char_type __cu = __ctype.toupper(*__beg);
+		  for (size_t __i3 = 0; __i3 < __nmatches; ++__i3)
+		    {
+		      __name = __names[__matches[__i3]];
+		      if (__lengths[__i3] > __pos
+			  && (__ctype.tolower(__name[__pos]) == __cl
+			      || __ctype.toupper(__name[__pos]) == __cu))
+			{
+			  __match_longer = true;
+			  break;
+			}
+		    }
+		}
+	      for (size_t __i4 = 0; __i4 < __nmatches;)
+		if (__match_longer == (__lengths[__i4] == __pos))
+		  {
+		    __matches[__i4] = __matches[--__nmatches];
+		    __lengths[__i4] = __lengths[__nmatches];
+		  }
+		else
+		  ++__i4;
+	      if (__match_longer)
+		{
+		  __minlen = __lengths[0];
+		  for (size_t __i5 = 1; __i5 < __nmatches; ++__i5)
+		    __minlen = std::min(__minlen, __lengths[__i5]);
+		}
+	      else
+		{
+		  // Deal with May being full as well as abbreviated month
+		  // name.  Pick the smaller index.
+		  if (__nmatches == 2 && (__indexlen & 1) == 0)
+		    {
+		      if (__matches[0] < __indexlen / 2)
+			{
+			  if (__matches[1] == __matches[0] + __indexlen / 2)
+			    __nmatches = 1;
+			}
+		      else if (__matches[1] == __matches[0] - __indexlen / 2)
+			{
+			  __matches[0] = __matches[1];
+			  __lengths[0] = __lengths[1];
+			  __nmatches = 1;
+			}
+		    }
+		  __begupdated = true;
+		  break;
+		}
+	    }
+	  if (__pos < __minlen && __beg != __end)
+	    {
+	      // TODO real case-insensitive comparison
+	      const char_type __cl = __ctype.tolower(*__beg);
+	      const char_type __cu = __ctype.toupper(*__beg);
+	      for (size_t __i6 = 0; __i6 < __nmatches;)
+		{
+		  __name = __names[__matches[__i6]];
+		  if (__ctype.tolower(__name[__pos]) != __cl
+		      && __ctype.toupper(__name[__pos]) != __cu)
+		    {
+		      __matches[__i6] = __matches[--__nmatches];
+		      __lengths[__i6] = __lengths[__nmatches];
+		    }
+		  else
+		    ++__i6;
+		}
+	    }
+	  else
+	    break;
+	}
+
+      if (__nmatches == 1)
+	{
+	  // Make sure found name is completely extracted.
+	  if (!__begupdated)
+	    {
+	      ++__beg;
+	      ++__pos;
+	    }
+	  __name = __names[__matches[0]];
+	  const size_t __len = __lengths[0];
+	  while (__pos < __len
+		 && __beg != __end
+		 // TODO real case-insensitive comparison
+		 && (__ctype.tolower(__name[__pos]) == __ctype.tolower(*__beg)
+		     || (__ctype.toupper(__name[__pos])
+			 == __ctype.toupper(*__beg))))
+	    ++__beg, (void)++__pos;
+
+	  if (__len == __pos)
+	    __member = __matches[0];
+	  else
+	    __testvalid = false;
+	}
+      else
+	__testvalid = false;
+      if (!__testvalid)
+	__err |= ios_base::failbit;
+
+      return __beg;
+    }
+
+  template<typename _CharT, typename _InIter>
+    _InIter
+    time_get<_CharT, _InIter>::
+    _M_extract_wday_or_month(iter_type __beg, iter_type __end, int& __member,
+			     const _CharT** __names, size_t __indexlen,
+			     ios_base& __io, ios_base::iostate& __err) const
+    {
+      typedef char_traits<_CharT>		__traits_type;
+      const locale& __loc = __io._M_getloc();
+      const ctype<_CharT>& __ctype = use_facet<ctype<_CharT> >(__loc);
+
+      int* __matches = static_cast<int*>(__builtin_alloca(2 * sizeof(int)
+							  * __indexlen));
+      size_t __nmatches = 0;
+      size_t* __matches_lengths = 0;
+      size_t __pos = 0;
+
+      if (__beg != __end)
+	{
+	  const char_type __c = *__beg;
+	  for (size_t __i = 0; __i < 2 * __indexlen; ++__i)
+	    if (__c == __names[__i][0]
+		|| __c == __ctype.toupper(__names[__i][0]))
+	      __matches[__nmatches++] = __i;
+	}
+
+      if (__nmatches)
+	{
+	  ++__beg;
+	  ++__pos;
+
+	  __matches_lengths
+	    = static_cast<size_t*>(__builtin_alloca(sizeof(size_t)
+						    * __nmatches));
+	  for (size_t __i = 0; __i < __nmatches; ++__i)
+	    __matches_lengths[__i]
+	      = __traits_type::length(__names[__matches[__i]]);
+	}
+
+      for (; __beg != __end; ++__beg, (void)++__pos)
+	{
+	  size_t __nskipped = 0;
+	  const char_type __c = *__beg;
+	  for (size_t __i = 0; __i < __nmatches;)
+	    {
+	      const char_type* __name = __names[__matches[__i]];
+	      if (__pos >= __matches_lengths[__i])
+		++__nskipped, ++__i;
+	      else if (!(__name[__pos] == __c))
+		{
+		  --__nmatches;
+		  __matches[__i] = __matches[__nmatches];
+		  __matches_lengths[__i] = __matches_lengths[__nmatches];
+		}
+	      else
+		++__i;
+	    }
+	  if (__nskipped == __nmatches)
+	    break;
+	}
+
+      if ((__nmatches == 1 && __matches_lengths[0] == __pos)
+	  || (__nmatches == 2 && (__matches_lengths[0] == __pos
+				  || __matches_lengths[1] == __pos)))
+	__member = (__matches[0] >= (int)__indexlen
+		    ? __matches[0] - (int)__indexlen : __matches[0]);
+      else
+	__err |= ios_base::failbit;
+
+      return __beg;
+    }
+
+  template<typename _CharT, typename _InIter>
+    _InIter
+    time_get<_CharT, _InIter>::
+    do_get_time(iter_type __beg, iter_type __end, ios_base& __io,
+		ios_base::iostate& __err, tm* __tm) const
+    {
+      const locale& __loc = __io._M_getloc();
+      const __timepunct<_CharT>& __tp = use_facet<__timepunct<_CharT> >(__loc);
+      const char_type*  __times[2];
+      __tp._M_time_formats(__times);
+      __time_get_state __state = __time_get_state();
+      __beg = _M_extract_via_format(__beg, __end, __io, __err, 
+				    __tm, __times[0], __state);
+      __state._M_finalize_state(__tm);
+      if (__beg == __end)
+	__err |= ios_base::eofbit;
+      return __beg;
+    }
+
+  template<typename _CharT, typename _InIter>
+    _InIter
+    time_get<_CharT, _InIter>::
+    do_get_date(iter_type __beg, iter_type __end, ios_base& __io,
+		ios_base::iostate& __err, tm* __tm) const
+    {
+      const locale& __loc = __io._M_getloc();
+      const __timepunct<_CharT>& __tp = use_facet<__timepunct<_CharT> >(__loc);
+      const char_type*  __dates[2];
+      __tp._M_date_formats(__dates);
+      __time_get_state __state = __time_get_state();
+      __beg = _M_extract_via_format(__beg, __end, __io, __err, 
+				    __tm, __dates[0], __state);
+      __state._M_finalize_state(__tm);
+      if (__beg == __end)
+	__err |= ios_base::eofbit;
+      return __beg;
+    }
+
+  template<typename _CharT, typename _InIter>
+    _InIter
+    time_get<_CharT, _InIter>::
+    do_get_weekday(iter_type __beg, iter_type __end, ios_base& __io,
+		   ios_base::iostate& __err, tm* __tm) const
+    {
+      const locale& __loc = __io._M_getloc();
+      const __timepunct<_CharT>& __tp = use_facet<__timepunct<_CharT> >(__loc);
+      const char_type* __days[14];
+      __tp._M_days_abbreviated(__days);
+      __tp._M_days(__days + 7);
+      int __tmpwday;
+      ios_base::iostate __tmperr = ios_base::goodbit;
+
+      __beg = _M_extract_wday_or_month(__beg, __end, __tmpwday, __days, 7,
+				       __io, __tmperr);
+      if (!__tmperr)
+	__tm->tm_wday = __tmpwday;
+      else
+	__err |= ios_base::failbit;
+
+      if (__beg == __end)
+	__err |= ios_base::eofbit;
+      return __beg;
+     }
+
+  template<typename _CharT, typename _InIter>
+    _InIter
+    time_get<_CharT, _InIter>::
+    do_get_monthname(iter_type __beg, iter_type __end,
+                     ios_base& __io, ios_base::iostate& __err, tm* __tm) const
+    {
+      const locale& __loc = __io._M_getloc();
+      const __timepunct<_CharT>& __tp = use_facet<__timepunct<_CharT> >(__loc);
+      const char_type*  __months[24];
+      __tp._M_months_abbreviated(__months);
+      __tp._M_months(__months + 12);
+      int __tmpmon;
+      ios_base::iostate __tmperr = ios_base::goodbit;
+
+      __beg = _M_extract_wday_or_month(__beg, __end, __tmpmon, __months, 12,
+				       __io, __tmperr);
+      if (!__tmperr)
+	__tm->tm_mon = __tmpmon;
+      else
+	__err |= ios_base::failbit;
+
+      if (__beg == __end)
+	__err |= ios_base::eofbit;
+      return __beg;
+    }
+
+  template<typename _CharT, typename _InIter>
+    _InIter
+    time_get<_CharT, _InIter>::
+    do_get_year(iter_type __beg, iter_type __end, ios_base& __io,
+		ios_base::iostate& __err, tm* __tm) const
+    {
+      int __tmpyear;
+      ios_base::iostate __tmperr = ios_base::goodbit;
+      const locale& __loc = __io._M_getloc();
+      const ctype<_CharT>& __ctype = use_facet<ctype<_CharT> >(__loc);
+
+      __beg = _M_extract_num(__beg, __end, __tmpyear, 0, 99, 2,
+			     __io, __tmperr);
+      if (!__tmperr)
+	{
+	  char __c = 0;
+	  if (__beg != __end)
+	    __c = __ctype.narrow(*__beg, '*');
+	  // For 1-2 digit year, assume 69-99 is 1969-1999, 0-68 is 2000-2068.
+	  // For 3-4 digit year, use it as year.
+	  // __tm->tm_year needs year - 1900 though.
+	  if (__c >= '0' && __c <= '9')
+	    {
+	      ++__beg;
+	      __tmpyear = __tmpyear * 10 + (__c - '0');
+	      if (__beg != __end)
+		{
+		  __c = __ctype.narrow(*__beg, '*');
+		  if (__c >= '0' && __c <= '9')
+		    {
+		      ++__beg;
+		      __tmpyear = __tmpyear * 10 + (__c - '0');
+		    }
+		}
+	      __tmpyear -= 1900;
+	    }
+	  else if (__tmpyear < 69)
+	    __tmpyear += 100;
+	  __tm->tm_year = __tmpyear;
+	}
+      else
+	__err |= ios_base::failbit;
+
+      if (__beg == __end)
+	__err |= ios_base::eofbit;
+      return __beg;
+    }
+
+#if __cplusplus >= 201103L
+  template<typename _CharT, typename _InIter>
+    inline
+    _InIter
+    time_get<_CharT, _InIter>::
+    get(iter_type __s, iter_type __end, ios_base& __io,
+        ios_base::iostate& __err, tm* __tm, const char_type* __fmt,
+        const char_type* __fmtend) const
+    {
+      const locale& __loc = __io._M_getloc();
+      ctype<_CharT> const& __ctype = use_facet<ctype<_CharT> >(__loc);
+      __err = ios_base::goodbit;
+      bool __use_state = false;
+#if __GNUC__ >= 5 && !defined(__clang__)
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wpmf-conversions"
+      // Nasty hack.  The C++ standard mandates that get invokes the do_get
+      // virtual method, but unfortunately at least without an ABI change
+      // for the facets we can't keep state across the different do_get
+      // calls.  So e.g. if __fmt is "%p %I:%M:%S", we can't handle it
+      // properly, because we first handle the %p am/pm specifier and only
+      // later the 12-hour format specifier.
+      if ((void*)(this->*(&time_get::do_get)) == (void*)(&time_get::do_get))
+	__use_state = true;
+#pragma GCC diagnostic pop
+#endif
+      __time_get_state __state = __time_get_state();
+      while (__fmt != __fmtend &&
+             __err == ios_base::goodbit)
+        {
+          if (__s == __end)
+            {
+              __err = ios_base::eofbit | ios_base::failbit;
+              break;
+            }
+          else if (__ctype.narrow(*__fmt, 0) == '%')
+            {
+	      const char_type* __fmt_start = __fmt;
+              char __format;
+              char __mod = 0;
+              if (++__fmt == __fmtend)
+                {
+                  __err = ios_base::failbit;
+                  break;
+                }
+              const char __c = __ctype.narrow(*__fmt, 0);
+              if (__c != 'E' && __c != 'O')
+                __format = __c;
+              else if (++__fmt != __fmtend)
+                {
+                  __mod = __c;
+                  __format = __ctype.narrow(*__fmt, 0);
+                }
+              else
+                {
+                  __err = ios_base::failbit;
+                  break;
+                }
+	      if (__use_state)
+		{
+		  char_type __new_fmt[4];
+		  __new_fmt[0] = __fmt_start[0];
+		  __new_fmt[1] = __fmt_start[1];
+		  if (__mod)
+		    {
+		      __new_fmt[2] = __fmt_start[2];
+		      __new_fmt[3] = char_type();
+		    }
+		  else
+		    __new_fmt[2] = char_type();
+		  __s = _M_extract_via_format(__s, __end, __io, __err, __tm,
+					      __new_fmt, __state);
+		  if (__s == __end)
+		    __err |= ios_base::eofbit;
+		}
+	      else
+		__s = this->do_get(__s, __end, __io, __err, __tm, __format,
+				   __mod);
+              ++__fmt;
+            }
+          else if (__ctype.is(ctype_base::space, *__fmt))
+            {
+              ++__fmt;
+              while (__fmt != __fmtend &&
+                     __ctype.is(ctype_base::space, *__fmt))
+                ++__fmt;
+
+              while (__s != __end &&
+                     __ctype.is(ctype_base::space, *__s))
+                ++__s;
+            }
+          // TODO real case-insensitive comparison
+          else if (__ctype.tolower(*__s) == __ctype.tolower(*__fmt) ||
+                   __ctype.toupper(*__s) == __ctype.toupper(*__fmt))
+            {
+              ++__s;
+              ++__fmt;
+            }
+          else
+            {
+              __err = ios_base::failbit;
+              break;
+            }
+        }
+      if (__use_state)
+	__state._M_finalize_state(__tm);
+      return __s;
+    }
+
+  template<typename _CharT, typename _InIter>
+    inline
+    _InIter
+    time_get<_CharT, _InIter>::
+    do_get(iter_type __beg, iter_type __end, ios_base& __io,
+           ios_base::iostate& __err, tm* __tm,
+           char __format, char __mod) const
+    {
+      const locale& __loc = __io._M_getloc();
+      ctype<_CharT> const& __ctype = use_facet<ctype<_CharT> >(__loc);
+      __err = ios_base::goodbit;
+
+      char_type __fmt[4];
+      __fmt[0] = __ctype.widen('%');
+      if (!__mod)
+        {
+          __fmt[1] = __format;
+          __fmt[2] = char_type();
+        }
+      else
+        {
+          __fmt[1] = __mod;
+          __fmt[2] = __format;
+          __fmt[3] = char_type();
+        }
+
+      __time_get_state __state = __time_get_state();
+      __beg = _M_extract_via_format(__beg, __end, __io, __err, __tm, __fmt,
+				    __state);
+      __state._M_finalize_state(__tm);
+      if (__beg == __end)
+	__err |= ios_base::eofbit;
+      return __beg;
+    }
+
+#endif // __cplusplus >= 201103L
+
+  template<typename _CharT, typename _OutIter>
+    _OutIter
+    time_put<_CharT, _OutIter>::
+    put(iter_type __s, ios_base& __io, char_type __fill, const tm* __tm,
+	const _CharT* __beg, const _CharT* __end) const
+    {
+      const locale& __loc = __io._M_getloc();
+      ctype<_CharT> const& __ctype = use_facet<ctype<_CharT> >(__loc);
+      for (; __beg != __end; ++__beg)
+	if (__ctype.narrow(*__beg, 0) != '%')
+	  {
+	    *__s = *__beg;
+	    ++__s;
+	  }
+	else if (++__beg != __end)
+	  {
+	    char __format;
+	    char __mod = 0;
+	    const char __c = __ctype.narrow(*__beg, 0);
+	    if (__c != 'E' && __c != 'O')
+	      __format = __c;
+	    else if (++__beg != __end)
+	      {
+		__mod = __c;
+		__format = __ctype.narrow(*__beg, 0);
+	      }
+	    else
+	      break;
+	    __s = this->do_put(__s, __io, __fill, __tm, __format, __mod);
+	  }
+	else
+	  break;
+      return __s;
+    }
+
+  template<typename _CharT, typename _OutIter>
+    _OutIter
+    time_put<_CharT, _OutIter>::
+    do_put(iter_type __s, ios_base& __io, char_type, const tm* __tm,
+	   char __format, char __mod) const
+    {
+      const locale& __loc = __io._M_getloc();
+      ctype<_CharT> const& __ctype = use_facet<ctype<_CharT> >(__loc);
+      __timepunct<_CharT> const& __tp = use_facet<__timepunct<_CharT> >(__loc);
+
+      // NB: This size is arbitrary. Should this be a data member,
+      // initialized at construction?
+      const size_t __maxlen = 128;
+      char_type __res[__maxlen];
+
+      // NB: In IEE 1003.1-200x, and perhaps other locale models, it
+      // is possible that the format character will be longer than one
+      // character. Possibilities include 'E' or 'O' followed by a
+      // format character: if __mod is not the default argument, assume
+      // it's a valid modifier.
+      char_type __fmt[4];
+      __fmt[0] = __ctype.widen('%');
+      if (!__mod)
+	{
+	  __fmt[1] = __format;
+	  __fmt[2] = char_type();
+	}
+      else
+	{
+	  __fmt[1] = __mod;
+	  __fmt[2] = __format;
+	  __fmt[3] = char_type();
+	}
+
+      __tp._M_put(__res, __maxlen, __fmt, __tm);
+
+      // Write resulting, fully-formatted string to output iterator.
+      return std::__write(__s, __res, char_traits<char_type>::length(__res));
+    }
+
+
+  // Inhibit implicit instantiations for required instantiations,
+  // which are defined via explicit instantiations elsewhere.
+#if _GLIBCXX_EXTERN_TEMPLATE
+  extern template class moneypunct<char, false>;
+  extern template class moneypunct<char, true>;
+  extern template class moneypunct_byname<char, false>;
+  extern template class moneypunct_byname<char, true>;
+  extern template class _GLIBCXX_NAMESPACE_LDBL_OR_CXX11 money_get<char>;
+  extern template class _GLIBCXX_NAMESPACE_LDBL_OR_CXX11 money_put<char>;
+  extern template class __timepunct<char>;
+  extern template class time_put<char>;
+  extern template class time_put_byname<char>;
+  extern template class time_get<char>;
+  extern template class time_get_byname<char>;
+  extern template class messages<char>;
+  extern template class messages_byname<char>;
+
+  extern template
+    const moneypunct<char, true>&
+    use_facet<moneypunct<char, true> >(const locale&);
+
+  extern template
+    const moneypunct<char, false>&
+    use_facet<moneypunct<char, false> >(const locale&);
+
+  extern template
+    const money_put<char>&
+    use_facet<money_put<char> >(const locale&);
+
+  extern template
+    const money_get<char>&
+    use_facet<money_get<char> >(const locale&);
+
+  extern template
+    const __timepunct<char>&
+    use_facet<__timepunct<char> >(const locale&);
+
+  extern template
+    const time_put<char>&
+    use_facet<time_put<char> >(const locale&);
+
+  extern template
+    const time_get<char>&
+    use_facet<time_get<char> >(const locale&);
+
+  extern template
+    const messages<char>&
+    use_facet<messages<char> >(const locale&);
+
+  extern template
+    bool
+    has_facet<moneypunct<char> >(const locale&);
+
+  extern template
+    bool
+    has_facet<money_put<char> >(const locale&);
+
+  extern template
+    bool
+    has_facet<money_get<char> >(const locale&);
+
+  extern template
+    bool
+    has_facet<__timepunct<char> >(const locale&);
+
+  extern template
+    bool
+    has_facet<time_put<char> >(const locale&);
+
+  extern template
+    bool
+    has_facet<time_get<char> >(const locale&);
+
+  extern template
+    bool
+    has_facet<messages<char> >(const locale&);
+
+#ifdef _GLIBCXX_USE_WCHAR_T
+  extern template class moneypunct<wchar_t, false>;
+  extern template class moneypunct<wchar_t, true>;
+  extern template class moneypunct_byname<wchar_t, false>;
+  extern template class moneypunct_byname<wchar_t, true>;
+  extern template class _GLIBCXX_NAMESPACE_LDBL_OR_CXX11 money_get<wchar_t>;
+  extern template class _GLIBCXX_NAMESPACE_LDBL_OR_CXX11 money_put<wchar_t>;
+  extern template class __timepunct<wchar_t>;
+  extern template class time_put<wchar_t>;
+  extern template class time_put_byname<wchar_t>;
+  extern template class time_get<wchar_t>;
+  extern template class time_get_byname<wchar_t>;
+  extern template class messages<wchar_t>;
+  extern template class messages_byname<wchar_t>;
+
+  extern template
+    const moneypunct<wchar_t, true>&
+    use_facet<moneypunct<wchar_t, true> >(const locale&);
+
+  extern template
+    const moneypunct<wchar_t, false>&
+    use_facet<moneypunct<wchar_t, false> >(const locale&);
+
+  extern template
+    const money_put<wchar_t>&
+    use_facet<money_put<wchar_t> >(const locale&);
+
+  extern template
+    const money_get<wchar_t>&
+    use_facet<money_get<wchar_t> >(const locale&);
+
+  extern template
+    const __timepunct<wchar_t>&
+    use_facet<__timepunct<wchar_t> >(const locale&);
+
+  extern template
+    const time_put<wchar_t>&
+    use_facet<time_put<wchar_t> >(const locale&);
+
+  extern template
+    const time_get<wchar_t>&
+    use_facet<time_get<wchar_t> >(const locale&);
+
+  extern template
+    const messages<wchar_t>&
+    use_facet<messages<wchar_t> >(const locale&);
+
+  extern template
+    bool
+    has_facet<moneypunct<wchar_t> >(const locale&);
+
+  extern template
+    bool
+    has_facet<money_put<wchar_t> >(const locale&);
+
+  extern template
+    bool
+    has_facet<money_get<wchar_t> >(const locale&);
+
+  extern template
+    bool
+    has_facet<__timepunct<wchar_t> >(const locale&);
+
+  extern template
+    bool
+    has_facet<time_put<wchar_t> >(const locale&);
+
+  extern template
+    bool
+    has_facet<time_get<wchar_t> >(const locale&);
+
+  extern template
+    bool
+    has_facet<messages<wchar_t> >(const locale&);
+#endif
+#endif
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@locale_facets_nonio.tcc.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@locale_facets_nonio.tcc.blob
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Binary files /dev/null and b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@locale_facets_nonio.tcc.blob differ
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@localefwd.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@localefwd.h
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--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@localefwd.h
@@ -0,0 +1,214 @@
+// <locale> Forward declarations -*- C++ -*-
+
+// Copyright (C) 1997-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/localefwd.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{locale}
+ */
+
+//
+// ISO C++ 14882: 22.1  Locales
+//
+
+#ifndef _LOCALE_FWD_H
+#define _LOCALE_FWD_H 1
+
+#pragma GCC system_header
+
+#include <bits/c++config.h>
+#include <bits/c++locale.h>  // Defines __c_locale, config-specific include
+#include <iosfwd>            // For ostreambuf_iterator, istreambuf_iterator
+#include <cctype>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /** 
+   *  @defgroup locales Locales
+   *
+   *  Classes and functions for internationalization and localization.
+   */
+
+  // 22.1.1 Locale
+  class locale;
+
+  template<typename _Facet>
+    bool
+    has_facet(const locale&) throw();
+
+  template<typename _Facet>
+    const _Facet&
+    use_facet(const locale&);
+
+  // 22.1.3 Convenience interfaces
+  template<typename _CharT>
+    bool
+    isspace(_CharT, const locale&);
+
+  template<typename _CharT>
+    bool
+    isprint(_CharT, const locale&);
+
+  template<typename _CharT>
+    bool
+    iscntrl(_CharT, const locale&);
+
+  template<typename _CharT>
+    bool
+    isupper(_CharT, const locale&);
+
+  template<typename _CharT>
+    bool
+    islower(_CharT, const locale&);
+
+  template<typename _CharT>
+    bool
+    isalpha(_CharT, const locale&);
+
+  template<typename _CharT>
+    bool
+    isdigit(_CharT, const locale&);
+
+  template<typename _CharT>
+    bool
+    ispunct(_CharT, const locale&);
+
+  template<typename _CharT>
+    bool
+    isxdigit(_CharT, const locale&);
+
+  template<typename _CharT>
+    bool
+    isalnum(_CharT, const locale&);
+
+  template<typename _CharT>
+    bool
+    isgraph(_CharT, const locale&);
+
+#if __cplusplus >= 201103L
+  template<typename _CharT>
+    bool
+    isblank(_CharT, const locale&);
+#endif
+
+  template<typename _CharT>
+    _CharT
+    toupper(_CharT, const locale&);
+
+  template<typename _CharT>
+    _CharT
+    tolower(_CharT, const locale&);
+
+  // 22.2.1 and 22.2.1.3 ctype
+  struct ctype_base;
+  template<typename _CharT>
+    class ctype;
+  template<> class ctype<char>;
+#ifdef _GLIBCXX_USE_WCHAR_T
+  template<> class ctype<wchar_t>;
+#endif
+  template<typename _CharT>
+    class ctype_byname;
+  // NB: Specialized for char and wchar_t in locale_facets.h.
+
+  class codecvt_base;
+  template<typename _InternT, typename _ExternT, typename _StateT>
+    class codecvt;
+  template<> class codecvt<char, char, mbstate_t>;
+#ifdef _GLIBCXX_USE_WCHAR_T
+  template<> class codecvt<wchar_t, char, mbstate_t>;
+#endif
+#if __cplusplus >= 201103L
+  template<> class codecvt<char16_t, char, mbstate_t>;
+  template<> class codecvt<char32_t, char, mbstate_t>;
+#ifdef _GLIBCXX_USE_CHAR8_T
+  template<> class codecvt<char16_t, char8_t, mbstate_t>;
+  template<> class codecvt<char32_t, char8_t, mbstate_t>;
+#endif
+#endif
+  template<typename _InternT, typename _ExternT, typename _StateT>
+    class codecvt_byname;
+
+  // 22.2.2 and 22.2.3 numeric
+_GLIBCXX_BEGIN_NAMESPACE_LDBL
+  template<typename _CharT, typename _InIter = istreambuf_iterator<_CharT> >
+    class num_get;
+  template<typename _CharT, typename _OutIter = ostreambuf_iterator<_CharT> >
+    class num_put;
+_GLIBCXX_END_NAMESPACE_LDBL
+_GLIBCXX_BEGIN_NAMESPACE_CXX11
+  template<typename _CharT> class numpunct;
+  template<typename _CharT> class numpunct_byname;
+_GLIBCXX_END_NAMESPACE_CXX11
+
+_GLIBCXX_BEGIN_NAMESPACE_CXX11
+  // 22.2.4 collation
+  template<typename _CharT>
+    class collate;
+  template<typename _CharT>
+    class collate_byname;
+_GLIBCXX_END_NAMESPACE_CXX11
+
+  // 22.2.5 date and time
+  class time_base;
+_GLIBCXX_BEGIN_NAMESPACE_CXX11
+  template<typename _CharT, typename _InIter =  istreambuf_iterator<_CharT> >
+    class time_get;
+  template<typename _CharT, typename _InIter =  istreambuf_iterator<_CharT> >
+    class time_get_byname;
+_GLIBCXX_END_NAMESPACE_CXX11
+  template<typename _CharT, typename _OutIter = ostreambuf_iterator<_CharT> >
+    class time_put;
+  template<typename _CharT, typename _OutIter = ostreambuf_iterator<_CharT> >
+    class time_put_byname;
+
+  // 22.2.6 money
+  class money_base;
+_GLIBCXX_BEGIN_NAMESPACE_LDBL_OR_CXX11
+  template<typename _CharT, typename _InIter =  istreambuf_iterator<_CharT> >
+    class money_get;
+  template<typename _CharT, typename _OutIter = ostreambuf_iterator<_CharT> >
+    class money_put;
+_GLIBCXX_END_NAMESPACE_LDBL_OR_CXX11
+_GLIBCXX_BEGIN_NAMESPACE_CXX11
+  template<typename _CharT, bool _Intl = false>
+    class moneypunct;
+  template<typename _CharT, bool _Intl = false>
+    class moneypunct_byname;
+_GLIBCXX_END_NAMESPACE_CXX11
+
+  // 22.2.7 message retrieval
+  struct messages_base;
+_GLIBCXX_BEGIN_NAMESPACE_CXX11
+  template<typename _CharT>
+    class messages;
+  template<typename _CharT>
+    class messages_byname;
+_GLIBCXX_END_NAMESPACE_CXX11
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@mask_array.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@mask_array.h
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@@ -0,0 +1,213 @@
+// The template and inlines for the -*- C++ -*- mask_array class.
+
+// Copyright (C) 1997-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/mask_array.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{valarray}
+ */
+
+// Written by Gabriel Dos Reis <Gabriel.Dos-Reis@DPTMaths.ENS-Cachan.Fr>
+
+#ifndef _MASK_ARRAY_H
+#define _MASK_ARRAY_H 1
+
+#pragma GCC system_header
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /**
+   * @addtogroup numeric_arrays
+   * @{
+   */
+
+  /**
+   *  @brief  Reference to selected subset of an array.
+   *
+   *  A mask_array is a reference to the actual elements of an array specified
+   *  by a bitmask in the form of an array of bool.  The way to get a
+   *  mask_array is to call operator[](valarray<bool>) on a valarray.  The
+   *  returned mask_array then permits carrying operations out on the
+   *  referenced subset of elements in the original valarray.
+   *
+   *  For example, if a mask_array is obtained using the array (false, true,
+   *  false, true) as an argument, the mask array has two elements referring
+   *  to array[1] and array[3] in the underlying array.
+   *
+   *  @param  Tp  Element type.
+   */
+  template <class _Tp>
+    class mask_array
+    {
+    public:
+      typedef _Tp value_type;
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 253. valarray helper functions are almost entirely useless
+
+      ///  Copy constructor.  Both slices refer to the same underlying array.
+      mask_array (const mask_array&);
+      
+      ///  Assignment operator.  Assigns elements to corresponding elements
+      ///  of @a a.
+      mask_array& operator=(const mask_array&);
+
+      void operator=(const valarray<_Tp>&) const;
+      ///  Multiply slice elements by corresponding elements of @a v.
+      void operator*=(const valarray<_Tp>&) const;
+      ///  Divide slice elements by corresponding elements of @a v.
+      void operator/=(const valarray<_Tp>&) const;
+      ///  Modulo slice elements by corresponding elements of @a v.
+      void operator%=(const valarray<_Tp>&) const;
+      ///  Add corresponding elements of @a v to slice elements.
+      void operator+=(const valarray<_Tp>&) const;
+      ///  Subtract corresponding elements of @a v from slice elements.
+      void operator-=(const valarray<_Tp>&) const;
+      ///  Logical xor slice elements with corresponding elements of @a v.
+      void operator^=(const valarray<_Tp>&) const;
+      ///  Logical and slice elements with corresponding elements of @a v.
+      void operator&=(const valarray<_Tp>&) const;
+      ///  Logical or slice elements with corresponding elements of @a v.
+      void operator|=(const valarray<_Tp>&) const;
+      ///  Left shift slice elements by corresponding elements of @a v.
+      void operator<<=(const valarray<_Tp>&) const;
+      ///  Right shift slice elements by corresponding elements of @a v.
+      void operator>>=(const valarray<_Tp>&) const;
+      ///  Assign all slice elements to @a t.
+      void operator=(const _Tp&) const;
+
+        //        ~mask_array ();
+
+      template<class _Dom>
+        void operator=(const _Expr<_Dom,_Tp>&) const;
+      template<class _Dom>
+        void operator*=(const _Expr<_Dom,_Tp>&) const;
+      template<class _Dom>
+        void operator/=(const _Expr<_Dom,_Tp>&) const;
+      template<class _Dom>
+        void operator%=(const _Expr<_Dom,_Tp>&) const;
+      template<class _Dom>
+        void operator+=(const _Expr<_Dom,_Tp>&) const;
+      template<class _Dom>
+        void operator-=(const _Expr<_Dom,_Tp>&) const;
+      template<class _Dom>
+        void operator^=(const _Expr<_Dom,_Tp>&) const;
+      template<class _Dom>
+        void operator&=(const _Expr<_Dom,_Tp>&) const;
+      template<class _Dom>
+        void operator|=(const _Expr<_Dom,_Tp>&) const;
+      template<class _Dom>
+        void operator<<=(const _Expr<_Dom,_Tp>&) const;
+      template<class _Dom>
+        void operator>>=(const _Expr<_Dom,_Tp>&) const;
+
+    private:
+      mask_array(_Array<_Tp>, size_t, _Array<bool>);
+      friend class valarray<_Tp>;
+
+      const size_t       _M_sz;
+      const _Array<bool> _M_mask;
+      const _Array<_Tp>  _M_array;
+
+#if __cplusplus < 201103L
+      // not implemented
+      mask_array();
+#else
+    public:
+      mask_array() = delete;
+#endif
+    };
+
+  template<typename _Tp>
+    inline mask_array<_Tp>::mask_array(const mask_array<_Tp>& __a)
+    : _M_sz(__a._M_sz), _M_mask(__a._M_mask), _M_array(__a._M_array) {}
+
+  template<typename _Tp>
+    inline
+    mask_array<_Tp>::mask_array(_Array<_Tp> __a, size_t __s, _Array<bool> __m)
+    : _M_sz(__s), _M_mask(__m), _M_array(__a) {}
+
+  template<typename _Tp>
+    inline mask_array<_Tp>&
+    mask_array<_Tp>::operator=(const mask_array<_Tp>& __a)
+    {
+      std::__valarray_copy(__a._M_array, __a._M_mask,
+			   _M_sz, _M_array, _M_mask);
+      return *this;
+    }
+
+  template<typename _Tp>
+    inline void
+    mask_array<_Tp>::operator=(const _Tp& __t) const
+    { std::__valarray_fill(_M_array, _M_sz, _M_mask, __t); }
+
+  template<typename _Tp>
+    inline void
+    mask_array<_Tp>::operator=(const valarray<_Tp>& __v) const
+    { std::__valarray_copy(_Array<_Tp>(__v), __v.size(), _M_array, _M_mask); }
+
+  template<typename _Tp>
+    template<class _Ex>
+      inline void
+      mask_array<_Tp>::operator=(const _Expr<_Ex, _Tp>& __e) const
+      { std::__valarray_copy(__e, __e.size(), _M_array, _M_mask); }
+
+#undef _DEFINE_VALARRAY_OPERATOR
+#define _DEFINE_VALARRAY_OPERATOR(_Op, _Name)				\
+  template<typename _Tp>						\
+    inline void								\
+    mask_array<_Tp>::operator _Op##=(const valarray<_Tp>& __v) const	\
+    {									\
+      _Array_augmented_##_Name(_M_array, _M_mask,			\
+			       _Array<_Tp>(__v), __v.size());		\
+    }									\
+									\
+  template<typename _Tp>                                                \
+    template<class _Dom>			                        \
+      inline void							\
+      mask_array<_Tp>::operator _Op##=(const _Expr<_Dom, _Tp>& __e) const\
+      {									\
+	_Array_augmented_##_Name(_M_array, _M_mask, __e, __e.size());   \
+      }
+
+_DEFINE_VALARRAY_OPERATOR(*, __multiplies)
+_DEFINE_VALARRAY_OPERATOR(/, __divides)
+_DEFINE_VALARRAY_OPERATOR(%, __modulus)
+_DEFINE_VALARRAY_OPERATOR(+, __plus)
+_DEFINE_VALARRAY_OPERATOR(-, __minus)
+_DEFINE_VALARRAY_OPERATOR(^, __bitwise_xor)
+_DEFINE_VALARRAY_OPERATOR(&, __bitwise_and)
+_DEFINE_VALARRAY_OPERATOR(|, __bitwise_or)
+_DEFINE_VALARRAY_OPERATOR(<<, __shift_left)
+_DEFINE_VALARRAY_OPERATOR(>>, __shift_right)
+
+#undef _DEFINE_VALARRAY_OPERATOR
+
+  /// @} group numeric_arrays
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif /* _MASK_ARRAY_H */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@mask_array.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@mask_array.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@memoryfwd.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@memoryfwd.h
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@@ -0,0 +1,83 @@
+// <memory> Forward declarations -*- C++ -*-
+
+// Copyright (C) 2001-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/*
+ * Copyright (c) 1996-1997
+ * Silicon Graphics Computer Systems, Inc.
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Silicon Graphics makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ */
+
+/** @file bits/memoryfwd.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{memory}
+ */
+
+#ifndef _MEMORYFWD_H
+#define _MEMORYFWD_H 1
+
+#pragma GCC system_header
+
+#include <bits/c++config.h>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /**
+   * @defgroup allocators Allocators
+   * @ingroup memory
+   *
+   * Classes encapsulating memory operations.
+   *
+   * @{
+   */
+
+  template<typename>
+    class allocator;
+
+  template<>
+    class allocator<void>;
+
+#if __cplusplus >= 201103L
+  /// Declare uses_allocator so it can be specialized in `<queue>` etc.
+  template<typename, typename>
+    struct uses_allocator;
+
+  template<typename>
+    struct allocator_traits;
+#endif
+
+  /// @} group memory
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@move.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@move.h
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@@ -0,0 +1,231 @@
+// Move, forward and identity for C++11 + swap -*- C++ -*-
+
+// Copyright (C) 2007-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/move.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{utility}
+ */
+
+#ifndef _MOVE_H
+#define _MOVE_H 1
+
+#include <bits/c++config.h>
+#if __cplusplus < 201103L
+# include <bits/concept_check.h>
+#endif
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  // Used, in C++03 mode too, by allocators, etc.
+  /**
+   *  @brief Same as C++11 std::addressof
+   *  @ingroup utilities
+   */
+  template<typename _Tp>
+    inline _GLIBCXX_CONSTEXPR _Tp*
+    __addressof(_Tp& __r) _GLIBCXX_NOEXCEPT
+    { return __builtin_addressof(__r); }
+
+#if __cplusplus >= 201103L
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#include <type_traits> // Brings in std::declval too.
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /**
+   *  @addtogroup utilities
+   *  @{
+   */
+
+  /**
+   *  @brief  Forward an lvalue.
+   *  @return The parameter cast to the specified type.
+   *
+   *  This function is used to implement "perfect forwarding".
+   */
+  template<typename _Tp>
+    _GLIBCXX_NODISCARD
+    constexpr _Tp&&
+    forward(typename std::remove_reference<_Tp>::type& __t) noexcept
+    { return static_cast<_Tp&&>(__t); }
+
+  /**
+   *  @brief  Forward an rvalue.
+   *  @return The parameter cast to the specified type.
+   *
+   *  This function is used to implement "perfect forwarding".
+   */
+  template<typename _Tp>
+    _GLIBCXX_NODISCARD
+    constexpr _Tp&&
+    forward(typename std::remove_reference<_Tp>::type&& __t) noexcept
+    {
+      static_assert(!std::is_lvalue_reference<_Tp>::value,
+	  "std::forward must not be used to convert an rvalue to an lvalue");
+      return static_cast<_Tp&&>(__t);
+    }
+
+  /**
+   *  @brief  Convert a value to an rvalue.
+   *  @param  __t  A thing of arbitrary type.
+   *  @return The parameter cast to an rvalue-reference to allow moving it.
+  */
+  template<typename _Tp>
+    _GLIBCXX_NODISCARD
+    constexpr typename std::remove_reference<_Tp>::type&&
+    move(_Tp&& __t) noexcept
+    { return static_cast<typename std::remove_reference<_Tp>::type&&>(__t); }
+
+
+  template<typename _Tp>
+    struct __move_if_noexcept_cond
+    : public __and_<__not_<is_nothrow_move_constructible<_Tp>>,
+                    is_copy_constructible<_Tp>>::type { };
+
+  /**
+   *  @brief  Conditionally convert a value to an rvalue.
+   *  @param  __x  A thing of arbitrary type.
+   *  @return The parameter, possibly cast to an rvalue-reference.
+   *
+   *  Same as std::move unless the type's move constructor could throw and the
+   *  type is copyable, in which case an lvalue-reference is returned instead.
+   */
+  template<typename _Tp>
+    _GLIBCXX_NODISCARD
+    constexpr
+    __conditional_t<__move_if_noexcept_cond<_Tp>::value, const _Tp&, _Tp&&>
+    move_if_noexcept(_Tp& __x) noexcept
+    { return std::move(__x); }
+
+  // declval, from type_traits.
+
+#if __cplusplus > 201402L
+  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+  // 2296. std::addressof should be constexpr
+# define __cpp_lib_addressof_constexpr 201603L
+#endif
+  /**
+   *  @brief Returns the actual address of the object or function
+   *         referenced by r, even in the presence of an overloaded
+   *         operator&.
+   *  @param  __r  Reference to an object or function.
+   *  @return   The actual address.
+  */
+  template<typename _Tp>
+    _GLIBCXX_NODISCARD
+    inline _GLIBCXX17_CONSTEXPR _Tp*
+    addressof(_Tp& __r) noexcept
+    { return std::__addressof(__r); }
+
+  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+  // 2598. addressof works on temporaries
+  template<typename _Tp>
+    const _Tp* addressof(const _Tp&&) = delete;
+
+  // C++11 version of std::exchange for internal use.
+  template <typename _Tp, typename _Up = _Tp>
+    _GLIBCXX20_CONSTEXPR
+    inline _Tp
+    __exchange(_Tp& __obj, _Up&& __new_val)
+    {
+      _Tp __old_val = std::move(__obj);
+      __obj = std::forward<_Up>(__new_val);
+      return __old_val;
+    }
+
+  /// @} group utilities
+
+#define _GLIBCXX_FWDREF(_Tp) _Tp&&
+#define _GLIBCXX_MOVE(__val) std::move(__val)
+#define _GLIBCXX_FORWARD(_Tp, __val) std::forward<_Tp>(__val)
+#else
+#define _GLIBCXX_FWDREF(_Tp) const _Tp&
+#define _GLIBCXX_MOVE(__val) (__val)
+#define _GLIBCXX_FORWARD(_Tp, __val) (__val)
+#endif
+
+  /**
+   *  @addtogroup utilities
+   *  @{
+   */
+
+  /**
+   *  @brief Swaps two values.
+   *  @param  __a  A thing of arbitrary type.
+   *  @param  __b  Another thing of arbitrary type.
+   *  @return   Nothing.
+  */
+  template<typename _Tp>
+    _GLIBCXX20_CONSTEXPR
+    inline
+#if __cplusplus >= 201103L
+    typename enable_if<__and_<__not_<__is_tuple_like<_Tp>>,
+			      is_move_constructible<_Tp>,
+			      is_move_assignable<_Tp>>::value>::type
+#else
+    void
+#endif
+    swap(_Tp& __a, _Tp& __b)
+    _GLIBCXX_NOEXCEPT_IF(__and_<is_nothrow_move_constructible<_Tp>,
+				is_nothrow_move_assignable<_Tp>>::value)
+    {
+#if __cplusplus < 201103L
+      // concept requirements
+      __glibcxx_function_requires(_SGIAssignableConcept<_Tp>)
+#endif
+      _Tp __tmp = _GLIBCXX_MOVE(__a);
+      __a = _GLIBCXX_MOVE(__b);
+      __b = _GLIBCXX_MOVE(__tmp);
+    }
+
+  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+  // DR 809. std::swap should be overloaded for array types.
+  /// Swap the contents of two arrays.
+  template<typename _Tp, size_t _Nm>
+    _GLIBCXX20_CONSTEXPR
+    inline
+#if __cplusplus >= 201103L
+    typename enable_if<__is_swappable<_Tp>::value>::type
+#else
+    void
+#endif
+    swap(_Tp (&__a)[_Nm], _Tp (&__b)[_Nm])
+    _GLIBCXX_NOEXCEPT_IF(__is_nothrow_swappable<_Tp>::value)
+    {
+      for (size_t __n = 0; __n < _Nm; ++__n)
+	swap(__a[__n], __b[__n]);
+    }
+
+  /// @} group utilities
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif /* _MOVE_H */
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@nested_exception.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@nested_exception.h
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@nested_exception.h
@@ -0,0 +1,171 @@
+// Nested Exception support header (nested_exception class) for -*- C++ -*-
+
+// Copyright (C) 2009-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/nested_exception.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{exception}
+ */
+
+#ifndef _GLIBCXX_NESTED_EXCEPTION_H
+#define _GLIBCXX_NESTED_EXCEPTION_H 1
+
+#pragma GCC visibility push(default)
+
+#if __cplusplus < 201103L
+# include <bits/c++0x_warning.h>
+#else
+
+#include <bits/c++config.h>
+#include <bits/move.h>
+
+extern "C++" {
+
+namespace std
+{
+  /**
+   * @addtogroup exceptions
+   * @{
+   */
+
+  /// Exception class with exception_ptr data member.
+  class nested_exception
+  {
+    exception_ptr _M_ptr;
+
+  public:
+    nested_exception() noexcept : _M_ptr(current_exception()) { }
+
+    nested_exception(const nested_exception&) noexcept = default;
+
+    nested_exception& operator=(const nested_exception&) noexcept = default;
+
+    virtual ~nested_exception() noexcept;
+
+    [[noreturn]]
+    void
+    rethrow_nested() const
+    {
+      if (_M_ptr)
+	rethrow_exception(_M_ptr);
+      std::terminate();
+    }
+
+    exception_ptr
+    nested_ptr() const noexcept
+    { return _M_ptr; }
+  };
+
+  /// @cond undocumented
+
+  template<typename _Except>
+    struct _Nested_exception : public _Except, public nested_exception
+    {
+      explicit _Nested_exception(const _Except& __ex)
+      : _Except(__ex)
+      { }
+
+      explicit _Nested_exception(_Except&& __ex)
+      : _Except(static_cast<_Except&&>(__ex))
+      { }
+    };
+
+  // [except.nested]/8
+  // Throw an exception of unspecified type that is publicly derived from
+  // both remove_reference_t<_Tp> and nested_exception.
+  template<typename _Tp>
+    [[noreturn]]
+    inline void
+    __throw_with_nested_impl(_Tp&& __t, true_type)
+    {
+      using _Up = typename remove_reference<_Tp>::type;
+      throw _Nested_exception<_Up>{std::forward<_Tp>(__t)};
+    }
+
+  template<typename _Tp>
+    [[noreturn]]
+    inline void
+    __throw_with_nested_impl(_Tp&& __t, false_type)
+    { throw std::forward<_Tp>(__t); }
+
+  /// @endcond
+
+  /// If @p __t is derived from nested_exception, throws @p __t.
+  /// Else, throws an implementation-defined object derived from both.
+  template<typename _Tp>
+    [[noreturn]]
+    inline void
+    throw_with_nested(_Tp&& __t)
+    {
+      using _Up = typename decay<_Tp>::type;
+      using _CopyConstructible
+	= __and_<is_copy_constructible<_Up>, is_move_constructible<_Up>>;
+      static_assert(_CopyConstructible::value,
+	  "throw_with_nested argument must be CopyConstructible");
+      using __nest = __and_<is_class<_Up>, __bool_constant<!__is_final(_Up)>,
+			    __not_<is_base_of<nested_exception, _Up>>>;
+      std::__throw_with_nested_impl(std::forward<_Tp>(__t), __nest{});
+    }
+
+  /// @cond undocumented
+
+  // Determine if dynamic_cast<const nested_exception&> would be well-formed.
+  template<typename _Tp>
+    using __rethrow_if_nested_cond = typename enable_if<
+      __and_<is_polymorphic<_Tp>,
+	     __or_<__not_<is_base_of<nested_exception, _Tp>>,
+		   is_convertible<_Tp*, nested_exception*>>>::value
+    >::type;
+
+  // Attempt dynamic_cast to nested_exception and call rethrow_nested().
+  template<typename _Ex>
+    inline __rethrow_if_nested_cond<_Ex>
+    __rethrow_if_nested_impl(const _Ex* __ptr)
+    {
+      if (auto __ne_ptr = dynamic_cast<const nested_exception*>(__ptr))
+	__ne_ptr->rethrow_nested();
+    }
+
+  // Otherwise, no effects.
+  inline void
+  __rethrow_if_nested_impl(const void*)
+  { }
+
+  /// @endcond
+
+  /// If @p __ex is derived from nested_exception, @p __ex.rethrow_nested().
+  template<typename _Ex>
+    inline void
+    rethrow_if_nested(const _Ex& __ex)
+    { std::__rethrow_if_nested_impl(std::__addressof(__ex)); }
+
+  /// @} group exceptions
+} // namespace std
+
+} // extern "C++"
+
+#endif // C++11
+
+#pragma GCC visibility pop
+
+#endif // _GLIBCXX_NESTED_EXCEPTION_H
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@nested_exception.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@nested_exception.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@new_allocator.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@new_allocator.h
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--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@new_allocator.h
@@ -0,0 +1,223 @@
+// Allocator that wraps operator new -*- C++ -*-
+
+// Copyright (C) 2001-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/new_allocator.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{memory}
+ */
+
+#ifndef _STD_NEW_ALLOCATOR_H
+#define _STD_NEW_ALLOCATOR_H 1
+
+#include <bits/c++config.h>
+#include <new>
+#include <bits/functexcept.h>
+#include <bits/move.h>
+#if __cplusplus >= 201103L
+#include <type_traits>
+#endif
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /**
+   *  @brief  An allocator that uses global new, as per C++03 [20.4.1].
+   *  @ingroup allocators
+   *
+   *  This is precisely the allocator defined in the C++ Standard.
+   *    - all allocation calls operator new
+   *    - all deallocation calls operator delete
+   *
+   *  @tparam  _Tp  Type of allocated object.
+   */
+  template<typename _Tp>
+    class __new_allocator
+    {
+    public:
+      typedef _Tp        value_type;
+      typedef std::size_t     size_type;
+      typedef std::ptrdiff_t  difference_type;
+#if __cplusplus <= 201703L
+      typedef _Tp*       pointer;
+      typedef const _Tp* const_pointer;
+      typedef _Tp&       reference;
+      typedef const _Tp& const_reference;
+
+      template<typename _Tp1>
+	struct rebind
+	{ typedef __new_allocator<_Tp1> other; };
+#endif
+
+#if __cplusplus >= 201103L
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 2103. propagate_on_container_move_assignment
+      typedef std::true_type propagate_on_container_move_assignment;
+#endif
+
+      _GLIBCXX20_CONSTEXPR
+      __new_allocator() _GLIBCXX_USE_NOEXCEPT { }
+
+      _GLIBCXX20_CONSTEXPR
+      __new_allocator(const __new_allocator&) _GLIBCXX_USE_NOEXCEPT { }
+
+      template<typename _Tp1>
+	_GLIBCXX20_CONSTEXPR
+	__new_allocator(const __new_allocator<_Tp1>&) _GLIBCXX_USE_NOEXCEPT { }
+
+#if __cplusplus <= 201703L
+      ~__new_allocator() _GLIBCXX_USE_NOEXCEPT { }
+
+      pointer
+      address(reference __x) const _GLIBCXX_NOEXCEPT
+      { return std::__addressof(__x); }
+
+      const_pointer
+      address(const_reference __x) const _GLIBCXX_NOEXCEPT
+      { return std::__addressof(__x); }
+#endif
+
+#if __has_builtin(__builtin_operator_new) >= 201802L
+# define _GLIBCXX_OPERATOR_NEW __builtin_operator_new
+# define _GLIBCXX_OPERATOR_DELETE __builtin_operator_delete
+#else
+# define _GLIBCXX_OPERATOR_NEW ::operator new
+# define _GLIBCXX_OPERATOR_DELETE ::operator delete
+#endif
+
+      // NB: __n is permitted to be 0.  The C++ standard says nothing
+      // about what the return value is when __n == 0.
+      _GLIBCXX_NODISCARD _Tp*
+      allocate(size_type __n, const void* = static_cast<const void*>(0))
+      {
+#if __cplusplus >= 201103L
+	// _GLIBCXX_RESOLVE_LIB_DEFECTS
+	// 3308. std::allocator<void>().allocate(n)
+	static_assert(sizeof(_Tp) != 0, "cannot allocate incomplete types");
+#endif
+
+	if (__builtin_expect(__n > this->_M_max_size(), false))
+	  {
+	    // _GLIBCXX_RESOLVE_LIB_DEFECTS
+	    // 3190. allocator::allocate sometimes returns too little storage
+	    if (__n > (std::size_t(-1) / sizeof(_Tp)))
+	      std::__throw_bad_array_new_length();
+	    std::__throw_bad_alloc();
+	  }
+
+#if __cpp_aligned_new
+	if (alignof(_Tp) > __STDCPP_DEFAULT_NEW_ALIGNMENT__)
+	  {
+	    std::align_val_t __al = std::align_val_t(alignof(_Tp));
+	    return static_cast<_Tp*>(_GLIBCXX_OPERATOR_NEW(__n * sizeof(_Tp),
+							   __al));
+	  }
+#endif
+	return static_cast<_Tp*>(_GLIBCXX_OPERATOR_NEW(__n * sizeof(_Tp)));
+      }
+
+      // __p is not permitted to be a null pointer.
+      void
+      deallocate(_Tp* __p, size_type __n __attribute__ ((__unused__)))
+      {
+#if __cpp_sized_deallocation
+# define _GLIBCXX_SIZED_DEALLOC(p, n) (p), (n) * sizeof(_Tp)
+#else
+# define _GLIBCXX_SIZED_DEALLOC(p, n) (p)
+#endif
+
+#if __cpp_aligned_new
+	if (alignof(_Tp) > __STDCPP_DEFAULT_NEW_ALIGNMENT__)
+	  {
+	    _GLIBCXX_OPERATOR_DELETE(_GLIBCXX_SIZED_DEALLOC(__p, __n),
+				     std::align_val_t(alignof(_Tp)));
+	    return;
+	  }
+#endif
+	_GLIBCXX_OPERATOR_DELETE(_GLIBCXX_SIZED_DEALLOC(__p, __n));
+      }
+
+#undef _GLIBCXX_SIZED_DEALLOC
+#undef _GLIBCXX_OPERATOR_DELETE
+#undef _GLIBCXX_OPERATOR_NEW
+
+#if __cplusplus <= 201703L
+      size_type
+      max_size() const _GLIBCXX_USE_NOEXCEPT
+      { return _M_max_size(); }
+
+#if __cplusplus >= 201103L
+      template<typename _Up, typename... _Args>
+	void
+	construct(_Up* __p, _Args&&... __args)
+	noexcept(std::is_nothrow_constructible<_Up, _Args...>::value)
+	{ ::new((void *)__p) _Up(std::forward<_Args>(__args)...); }
+
+      template<typename _Up>
+	void
+	destroy(_Up* __p)
+	noexcept(std::is_nothrow_destructible<_Up>::value)
+	{ __p->~_Up(); }
+#else
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 402. wrong new expression in [some_] allocator::construct
+      void
+      construct(pointer __p, const _Tp& __val)
+      { ::new((void *)__p) _Tp(__val); }
+
+      void
+      destroy(pointer __p) { __p->~_Tp(); }
+#endif
+#endif // ! C++20
+
+      template<typename _Up>
+	friend _GLIBCXX20_CONSTEXPR bool
+	operator==(const __new_allocator&, const __new_allocator<_Up>&)
+	_GLIBCXX_NOTHROW
+	{ return true; }
+
+#if __cpp_impl_three_way_comparison < 201907L
+      template<typename _Up>
+	friend _GLIBCXX20_CONSTEXPR bool
+	operator!=(const __new_allocator&, const __new_allocator<_Up>&)
+	_GLIBCXX_NOTHROW
+	{ return false; }
+#endif
+
+    private:
+      _GLIBCXX_CONSTEXPR size_type
+      _M_max_size() const _GLIBCXX_USE_NOEXCEPT
+      {
+#if __PTRDIFF_MAX__ < __SIZE_MAX__
+	return std::size_t(__PTRDIFF_MAX__) / sizeof(_Tp);
+#else
+	return std::size_t(-1) / sizeof(_Tp);
+#endif
+      }
+    };
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@new_allocator.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@new_allocator.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@ostream.tcc b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@ostream.tcc
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index 0000000000000000000000000000000000000000..ba337c81aa85c2e0f9c550e02929496364f040f1
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@ostream.tcc
@@ -0,0 +1,388 @@
+// ostream classes -*- C++ -*-
+
+// Copyright (C) 1997-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/ostream.tcc
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{ostream}
+ */
+
+//
+// ISO C++ 14882: 27.6.2  Output streams
+//
+
+#ifndef _OSTREAM_TCC
+#define _OSTREAM_TCC 1
+
+#pragma GCC system_header
+
+#include <bits/cxxabi_forced.h>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  template<typename _CharT, typename _Traits>
+    basic_ostream<_CharT, _Traits>::sentry::
+    sentry(basic_ostream<_CharT, _Traits>& __os)
+    : _M_ok(false), _M_os(__os)
+    {
+      // XXX MT
+      if (__os.tie() && __os.good())
+	__os.tie()->flush();
+
+      if (__os.good())
+	_M_ok = true;
+      else if (__os.bad())
+	__os.setstate(ios_base::failbit);
+    }
+
+  template<typename _CharT, typename _Traits>
+    template<typename _ValueT>
+      basic_ostream<_CharT, _Traits>&
+      basic_ostream<_CharT, _Traits>::
+      _M_insert(_ValueT __v)
+      {
+	sentry __cerb(*this);
+	if (__cerb)
+	  {
+	    ios_base::iostate __err = ios_base::goodbit;
+	    __try
+	      {
+		const __num_put_type& __np = __check_facet(this->_M_num_put);
+		if (__np.put(*this, *this, this->fill(), __v).failed())
+		  __err |= ios_base::badbit;
+	      }
+	    __catch(__cxxabiv1::__forced_unwind&)
+	      {
+		this->_M_setstate(ios_base::badbit);		
+		__throw_exception_again;
+	      }
+	    __catch(...)
+	      { this->_M_setstate(ios_base::badbit); }
+	    if (__err)
+	      this->setstate(__err);
+	  }
+	return *this;
+      }
+
+  template<typename _CharT, typename _Traits>
+    basic_ostream<_CharT, _Traits>&
+    basic_ostream<_CharT, _Traits>::
+    operator<<(short __n)
+    {
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 117. basic_ostream uses nonexistent num_put member functions.
+      const ios_base::fmtflags __fmt = this->flags() & ios_base::basefield;
+      if (__fmt == ios_base::oct || __fmt == ios_base::hex)
+	return _M_insert(static_cast<long>(static_cast<unsigned short>(__n)));
+      else
+	return _M_insert(static_cast<long>(__n));
+    }
+
+  template<typename _CharT, typename _Traits>
+    basic_ostream<_CharT, _Traits>&
+    basic_ostream<_CharT, _Traits>::
+    operator<<(int __n)
+    {
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 117. basic_ostream uses nonexistent num_put member functions.
+      const ios_base::fmtflags __fmt = this->flags() & ios_base::basefield;
+      if (__fmt == ios_base::oct || __fmt == ios_base::hex)
+	return _M_insert(static_cast<long>(static_cast<unsigned int>(__n)));
+      else
+	return _M_insert(static_cast<long>(__n));
+    }
+  
+  template<typename _CharT, typename _Traits>
+    basic_ostream<_CharT, _Traits>&
+    basic_ostream<_CharT, _Traits>::
+    operator<<(__streambuf_type* __sbin)
+    {
+      ios_base::iostate __err = ios_base::goodbit;
+      sentry __cerb(*this);
+      if (__cerb && __sbin)
+	{
+	  __try
+	    {
+	      if (!__copy_streambufs(__sbin, this->rdbuf()))
+		__err |= ios_base::failbit;
+	    }
+	  __catch(__cxxabiv1::__forced_unwind&)
+	    {
+	      this->_M_setstate(ios_base::badbit);		
+	      __throw_exception_again;
+	    }
+	  __catch(...)
+	    { this->_M_setstate(ios_base::failbit); }
+	}
+      else if (!__sbin)
+	__err |= ios_base::badbit;
+      if (__err)
+	this->setstate(__err);
+      return *this;
+    }
+
+  template<typename _CharT, typename _Traits>
+    basic_ostream<_CharT, _Traits>&
+    basic_ostream<_CharT, _Traits>::
+    put(char_type __c)
+    {
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // DR 60. What is a formatted input function?
+      // basic_ostream::put(char_type) is an unformatted output function.
+      // DR 63. Exception-handling policy for unformatted output.
+      // Unformatted output functions should catch exceptions thrown
+      // from streambuf members.
+      sentry __cerb(*this);
+      if (__cerb)
+	{
+	  ios_base::iostate __err = ios_base::goodbit;
+	  __try
+	    {
+	      const int_type __put = this->rdbuf()->sputc(__c);
+	      if (traits_type::eq_int_type(__put, traits_type::eof()))
+		__err |= ios_base::badbit;
+	    }
+	  __catch(__cxxabiv1::__forced_unwind&)
+	    {
+	      this->_M_setstate(ios_base::badbit);		
+	      __throw_exception_again;
+	    }
+	  __catch(...)
+	    { this->_M_setstate(ios_base::badbit); }
+	  if (__err)
+	    this->setstate(__err);
+	}
+      return *this;
+    }
+
+  template<typename _CharT, typename _Traits>
+    basic_ostream<_CharT, _Traits>&
+    basic_ostream<_CharT, _Traits>::
+    write(const _CharT* __s, streamsize __n)
+    {
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // DR 60. What is a formatted input function?
+      // basic_ostream::write(const char_type*, streamsize) is an
+      // unformatted output function.
+      // DR 63. Exception-handling policy for unformatted output.
+      // Unformatted output functions should catch exceptions thrown
+      // from streambuf members.
+      sentry __cerb(*this);
+      if (__cerb)
+	{
+	  ios_base::iostate __err = ios_base::goodbit;
+	  __try
+	    {
+	      if (this->rdbuf()->sputn(__s, __n) != __n)
+		__err = ios_base::badbit;
+	    }
+	  __catch(__cxxabiv1::__forced_unwind&)
+	    {
+	      this->_M_setstate(ios_base::badbit);		
+	      __throw_exception_again;
+	    }
+	  __catch(...)
+	    { this->_M_setstate(ios_base::badbit); }
+	  if (__err)
+	    this->setstate(ios_base::badbit);
+	}
+      return *this;
+    }
+
+  template<typename _CharT, typename _Traits>
+    basic_ostream<_CharT, _Traits>&
+    basic_ostream<_CharT, _Traits>::
+    flush()
+    {
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // DR 60. What is a formatted input function?
+      // basic_ostream::flush() is *not* an unformatted output function.
+      // 581. flush() not unformatted function
+      // basic_ostream::flush() *is* an unformatted output function.
+      if (__streambuf_type* __buf = this->rdbuf())
+	{
+	  sentry __cerb(*this);
+	  if (__cerb)
+	    {
+	      ios_base::iostate __err = ios_base::goodbit;
+	      __try
+		{
+		  if (this->rdbuf()->pubsync() == -1)
+		    __err |= ios_base::badbit;
+		}
+	      __catch(__cxxabiv1::__forced_unwind&)
+		{
+		  this->_M_setstate(ios_base::badbit);
+		  __throw_exception_again;
+		}
+	      __catch(...)
+		{ this->_M_setstate(ios_base::badbit); }
+	      if (__err)
+		this->setstate(__err);
+	    }
+	}
+      return *this;
+    }
+
+  template<typename _CharT, typename _Traits>
+    typename basic_ostream<_CharT, _Traits>::pos_type
+    basic_ostream<_CharT, _Traits>::
+    tellp()
+    {
+      sentry __cerb(*this);
+      pos_type __ret = pos_type(-1);
+      if (!this->fail())
+	__ret = this->rdbuf()->pubseekoff(0, ios_base::cur, ios_base::out);
+      return __ret;
+    }
+
+  template<typename _CharT, typename _Traits>
+    basic_ostream<_CharT, _Traits>&
+    basic_ostream<_CharT, _Traits>::
+    seekp(pos_type __pos)
+    {
+      sentry __cerb(*this);
+      if (!this->fail())
+	{
+	  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+	  // 136.  seekp, seekg setting wrong streams?
+	  const pos_type __p = this->rdbuf()->pubseekpos(__pos, ios_base::out);
+
+	  // 129. Need error indication from seekp() and seekg()
+	  if (__p == pos_type(off_type(-1)))
+	    this->setstate(ios_base::failbit);
+	}
+      return *this;
+    }
+
+  template<typename _CharT, typename _Traits>
+    basic_ostream<_CharT, _Traits>&
+    basic_ostream<_CharT, _Traits>::
+    seekp(off_type __off, ios_base::seekdir __dir)
+    {
+      sentry __cerb(*this);
+      if (!this->fail())
+	{
+	  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+	  // 136.  seekp, seekg setting wrong streams?
+	  const pos_type __p = this->rdbuf()->pubseekoff(__off, __dir,
+							 ios_base::out);
+
+	  // 129. Need error indication from seekp() and seekg()
+	  if (__p == pos_type(off_type(-1)))
+	    this->setstate(ios_base::failbit);
+	}
+      return *this;
+    }
+
+  template<typename _CharT, typename _Traits>
+    basic_ostream<_CharT, _Traits>&
+    operator<<(basic_ostream<_CharT, _Traits>& __out, const char* __s)
+    {
+      if (!__s)
+	__out.setstate(ios_base::badbit);
+      else
+	{
+	  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+	  // 167.  Improper use of traits_type::length()
+	  const size_t __clen = char_traits<char>::length(__s);
+	  __try
+	    {
+	      struct __ptr_guard
+	      {
+		_CharT *__p;
+		__ptr_guard (_CharT *__ip): __p(__ip) { }
+		~__ptr_guard() { delete[] __p; }
+		_CharT* __get() { return __p; }
+	      } __pg (new _CharT[__clen]);
+
+	      _CharT *__ws = __pg.__get();
+	      for (size_t  __i = 0; __i < __clen; ++__i)
+		__ws[__i] = __out.widen(__s[__i]);
+	      __ostream_insert(__out, __ws, __clen);
+	    }
+	  __catch(__cxxabiv1::__forced_unwind&)
+	    {
+	      __out._M_setstate(ios_base::badbit);
+	      __throw_exception_again;
+	    }
+	  __catch(...)
+	    { __out._M_setstate(ios_base::badbit); }
+	}
+      return __out;
+    }
+
+  // Inhibit implicit instantiations for required instantiations,
+  // which are defined via explicit instantiations elsewhere.
+#if _GLIBCXX_EXTERN_TEMPLATE
+  extern template class basic_ostream<char>;
+  extern template ostream& endl(ostream&);
+  extern template ostream& ends(ostream&);
+  extern template ostream& flush(ostream&);
+  extern template ostream& operator<<(ostream&, char);
+  extern template ostream& operator<<(ostream&, unsigned char);
+  extern template ostream& operator<<(ostream&, signed char);
+  extern template ostream& operator<<(ostream&, const char*);
+  extern template ostream& operator<<(ostream&, const unsigned char*);
+  extern template ostream& operator<<(ostream&, const signed char*);
+
+  extern template ostream& ostream::_M_insert(long);
+  extern template ostream& ostream::_M_insert(unsigned long);
+  extern template ostream& ostream::_M_insert(bool);
+#ifdef _GLIBCXX_USE_LONG_LONG
+  extern template ostream& ostream::_M_insert(long long);
+  extern template ostream& ostream::_M_insert(unsigned long long);
+#endif
+  extern template ostream& ostream::_M_insert(double);
+  extern template ostream& ostream::_M_insert(long double);
+  extern template ostream& ostream::_M_insert(const void*);
+
+#ifdef _GLIBCXX_USE_WCHAR_T
+  extern template class basic_ostream<wchar_t>;
+  extern template wostream& endl(wostream&);
+  extern template wostream& ends(wostream&);
+  extern template wostream& flush(wostream&);
+  extern template wostream& operator<<(wostream&, wchar_t);
+  extern template wostream& operator<<(wostream&, char);
+  extern template wostream& operator<<(wostream&, const wchar_t*);
+  extern template wostream& operator<<(wostream&, const char*);
+
+  extern template wostream& wostream::_M_insert(long);
+  extern template wostream& wostream::_M_insert(unsigned long);
+  extern template wostream& wostream::_M_insert(bool);
+#ifdef _GLIBCXX_USE_LONG_LONG
+  extern template wostream& wostream::_M_insert(long long);
+  extern template wostream& wostream::_M_insert(unsigned long long);
+#endif
+  extern template wostream& wostream::_M_insert(double);
+  extern template wostream& wostream::_M_insert(long double);
+  extern template wostream& wostream::_M_insert(const void*);
+#endif
+#endif
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@ostream.tcc.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@ostream.tcc.blob
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Binary files /dev/null and b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@ostream.tcc.blob differ
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@ostream_insert.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@ostream_insert.h
new file mode 100644
index 0000000000000000000000000000000000000000..9442ea130d364d230d44195ae0f12965681cc355
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@ostream_insert.h
@@ -0,0 +1,130 @@
+// Helpers for ostream inserters -*- C++ -*-
+
+// Copyright (C) 2007-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/ostream_insert.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{ostream}
+ */
+
+#ifndef _OSTREAM_INSERT_H
+#define _OSTREAM_INSERT_H 1
+
+#pragma GCC system_header
+
+#include <iosfwd>
+#include <bits/cxxabi_forced.h>
+#include <bits/exception_defines.h>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  template<typename _CharT, typename _Traits>
+    inline void
+    __ostream_write(basic_ostream<_CharT, _Traits>& __out,
+		    const _CharT* __s, streamsize __n)
+    {
+      typedef basic_ostream<_CharT, _Traits>       __ostream_type;      
+      typedef typename __ostream_type::ios_base    __ios_base;
+
+      const streamsize __put = __out.rdbuf()->sputn(__s, __n);
+      if (__put != __n)
+	__out.setstate(__ios_base::badbit);
+    }
+
+  template<typename _CharT, typename _Traits>
+    inline void
+    __ostream_fill(basic_ostream<_CharT, _Traits>& __out, streamsize __n)
+    {
+      typedef basic_ostream<_CharT, _Traits>       __ostream_type;      
+      typedef typename __ostream_type::ios_base    __ios_base;
+
+      const _CharT __c = __out.fill();
+      for (; __n > 0; --__n)
+	{
+	  const typename _Traits::int_type __put = __out.rdbuf()->sputc(__c);
+	  if (_Traits::eq_int_type(__put, _Traits::eof()))
+	    {
+	      __out.setstate(__ios_base::badbit);
+	      break;
+	    }
+	}
+    }
+
+  template<typename _CharT, typename _Traits>
+    basic_ostream<_CharT, _Traits>&
+    __ostream_insert(basic_ostream<_CharT, _Traits>& __out,
+		     const _CharT* __s, streamsize __n)
+    {
+      typedef basic_ostream<_CharT, _Traits>       __ostream_type;
+      typedef typename __ostream_type::ios_base    __ios_base;
+
+      typename __ostream_type::sentry __cerb(__out);
+      if (__cerb)
+	{
+	  __try
+	    {
+	      const streamsize __w = __out.width();
+	      if (__w > __n)
+		{
+		  const bool __left = ((__out.flags()
+					& __ios_base::adjustfield)
+				       == __ios_base::left);
+		  if (!__left)
+		    __ostream_fill(__out, __w - __n);
+		  if (__out.good())
+		    __ostream_write(__out, __s, __n);
+		  if (__left && __out.good())
+		    __ostream_fill(__out, __w - __n);
+		}
+	      else
+		__ostream_write(__out, __s, __n);
+	      __out.width(0);
+	    }
+	  __catch(__cxxabiv1::__forced_unwind&)
+	    {
+	      __out._M_setstate(__ios_base::badbit);
+	      __throw_exception_again;
+	    }
+	  __catch(...)
+	    { __out._M_setstate(__ios_base::badbit); }
+	}
+      return __out;
+    }
+
+  // Inhibit implicit instantiations for required instantiations,
+  // which are defined via explicit instantiations elsewhere.
+#if _GLIBCXX_EXTERN_TEMPLATE
+  extern template ostream& __ostream_insert(ostream&, const char*, streamsize);
+
+#ifdef _GLIBCXX_USE_WCHAR_T
+  extern template wostream& __ostream_insert(wostream&, const wchar_t*,
+					     streamsize);
+#endif
+#endif
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif /* _OSTREAM_INSERT_H */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@ostream_insert.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@ostream_insert.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@parse_numbers.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@parse_numbers.h
new file mode 100644
index 0000000000000000000000000000000000000000..ba21d882959c80a187001add6103b074b663e54e
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@parse_numbers.h
@@ -0,0 +1,295 @@
+// Components for compile-time parsing of numbers -*- C++ -*-
+
+// Copyright (C) 2013-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/parse_numbers.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{chrono}
+ */
+
+#ifndef _GLIBCXX_PARSE_NUMBERS_H
+#define _GLIBCXX_PARSE_NUMBERS_H 1
+
+#pragma GCC system_header
+
+// From n3642.pdf except I added binary literals and digit separator '\''.
+
+#if __cplusplus >= 201402L
+
+#include <type_traits>
+#include <ext/numeric_traits.h>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+namespace __parse_int
+{
+  template<unsigned _Base, char _Dig>
+    struct _Digit;
+
+  template<unsigned _Base>
+    struct _Digit<_Base, '0'> : integral_constant<unsigned, 0>
+    {
+      using __valid = true_type;
+    };
+
+  template<unsigned _Base>
+    struct _Digit<_Base, '1'> : integral_constant<unsigned, 1>
+    {
+      using __valid = true_type;
+    };
+
+  template<unsigned _Base, unsigned _Val>
+    struct _Digit_impl : integral_constant<unsigned, _Val>
+    {
+      static_assert(_Base > _Val, "invalid digit");
+      using __valid = true_type;
+    };
+
+  template<unsigned _Base>
+    struct _Digit<_Base, '2'> : _Digit_impl<_Base, 2>
+    { };
+
+  template<unsigned _Base>
+    struct _Digit<_Base, '3'> : _Digit_impl<_Base, 3>
+    { };
+
+  template<unsigned _Base>
+    struct _Digit<_Base, '4'> : _Digit_impl<_Base, 4>
+    { };
+
+  template<unsigned _Base>
+    struct _Digit<_Base, '5'> : _Digit_impl<_Base, 5>
+    { };
+
+  template<unsigned _Base>
+    struct _Digit<_Base, '6'> : _Digit_impl<_Base, 6>
+    { };
+
+  template<unsigned _Base>
+    struct _Digit<_Base, '7'> : _Digit_impl<_Base, 7>
+    { };
+
+  template<unsigned _Base>
+    struct _Digit<_Base, '8'> : _Digit_impl<_Base, 8>
+    { };
+
+  template<unsigned _Base>
+    struct _Digit<_Base, '9'> : _Digit_impl<_Base, 9>
+    { };
+
+  template<unsigned _Base>
+    struct _Digit<_Base, 'a'> : _Digit_impl<_Base, 0xa>
+    { };
+
+  template<unsigned _Base>
+    struct _Digit<_Base, 'A'> : _Digit_impl<_Base, 0xa>
+    { };
+
+  template<unsigned _Base>
+    struct _Digit<_Base, 'b'> : _Digit_impl<_Base, 0xb>
+    { };
+
+  template<unsigned _Base>
+    struct _Digit<_Base, 'B'> : _Digit_impl<_Base, 0xb>
+    { };
+
+  template<unsigned _Base>
+    struct _Digit<_Base, 'c'> : _Digit_impl<_Base, 0xc>
+    { };
+
+  template<unsigned _Base>
+    struct _Digit<_Base, 'C'> : _Digit_impl<_Base, 0xc>
+    { };
+
+  template<unsigned _Base>
+    struct _Digit<_Base, 'd'> : _Digit_impl<_Base, 0xd>
+    { };
+
+  template<unsigned _Base>
+    struct _Digit<_Base, 'D'> : _Digit_impl<_Base, 0xd>
+    { };
+
+  template<unsigned _Base>
+    struct _Digit<_Base, 'e'> : _Digit_impl<_Base, 0xe>
+    { };
+
+  template<unsigned _Base>
+    struct _Digit<_Base, 'E'> : _Digit_impl<_Base, 0xe>
+    { };
+
+  template<unsigned _Base>
+    struct _Digit<_Base, 'f'> : _Digit_impl<_Base, 0xf>
+    { };
+
+  template<unsigned _Base>
+    struct _Digit<_Base, 'F'> : _Digit_impl<_Base, 0xf>
+    { };
+
+  //  Digit separator
+  template<unsigned _Base>
+    struct _Digit<_Base, '\''> : integral_constant<unsigned, 0>
+    {
+      using __valid = false_type;
+    };
+
+//------------------------------------------------------------------------------
+
+  template<unsigned long long _Val>
+    using __ull_constant = integral_constant<unsigned long long, _Val>;
+
+  template<unsigned _Base, char _Dig, char... _Digs>
+    struct _Power_help
+    {
+      using __next = typename _Power_help<_Base, _Digs...>::type;
+      using __valid_digit = typename _Digit<_Base, _Dig>::__valid;
+      using type
+	= __ull_constant<__next::value * (__valid_digit{} ? _Base : 1ULL)>;
+    };
+
+  template<unsigned _Base, char _Dig>
+    struct _Power_help<_Base, _Dig>
+    {
+      using __valid_digit = typename _Digit<_Base, _Dig>::__valid;
+      using type = __ull_constant<__valid_digit::value>;
+    };
+
+  template<unsigned _Base, char... _Digs>
+    struct _Power : _Power_help<_Base, _Digs...>::type
+    { };
+
+  template<unsigned _Base>
+    struct _Power<_Base> : __ull_constant<0>
+    { };
+
+//------------------------------------------------------------------------------
+
+  template<unsigned _Base, unsigned long long _Pow, char _Dig, char... _Digs>
+    struct _Number_help
+    {
+      using __digit = _Digit<_Base, _Dig>;
+      using __valid_digit = typename __digit::__valid;
+      using __next = _Number_help<_Base,
+				  __valid_digit::value ? _Pow / _Base : _Pow,
+				  _Digs...>;
+      using type = __ull_constant<_Pow * __digit::value + __next::type::value>;
+      static_assert((type::value / _Pow) == __digit::value,
+		    "integer literal does not fit in unsigned long long");
+    };
+
+  // Skip past digit separators:
+  template<unsigned _Base, unsigned long long _Pow, char _Dig, char..._Digs>
+    struct _Number_help<_Base, _Pow, '\'', _Dig, _Digs...>
+    : _Number_help<_Base, _Pow, _Dig, _Digs...>
+    { };
+
+  // Terminating case for recursion:
+  template<unsigned _Base, char _Dig>
+    struct _Number_help<_Base, 1ULL, _Dig>
+    {
+      using type = __ull_constant<_Digit<_Base, _Dig>::value>;
+    };
+
+  template<unsigned _Base, char... _Digs>
+    struct _Number
+    : _Number_help<_Base, _Power<_Base, _Digs...>::value, _Digs...>::type
+    { };
+
+  template<unsigned _Base>
+    struct _Number<_Base>
+    : __ull_constant<0>
+    { };
+
+//------------------------------------------------------------------------------
+
+  template<char... _Digs>
+    struct _Parse_int;
+
+  template<char... _Digs>
+    struct _Parse_int<'0', 'b', _Digs...>
+    : _Number<2U, _Digs...>::type
+    { };
+
+  template<char... _Digs>
+    struct _Parse_int<'0', 'B', _Digs...>
+    : _Number<2U, _Digs...>::type
+    { };
+
+  template<char... _Digs>
+    struct _Parse_int<'0', 'x', _Digs...>
+    : _Number<16U, _Digs...>::type
+    { };
+
+  template<char... _Digs>
+    struct _Parse_int<'0', 'X', _Digs...>
+    : _Number<16U, _Digs...>::type
+    { };
+
+  template<char... _Digs>
+    struct _Parse_int<'0', _Digs...>
+    : _Number<8U, _Digs...>::type
+    { };
+
+  template<char... _Digs>
+    struct _Parse_int
+    : _Number<10U, _Digs...>::type
+    { };
+
+} // namespace __parse_int
+
+
+namespace __select_int
+{
+  template<unsigned long long _Val, typename... _Ints>
+    struct _Select_int_base;
+
+  template<unsigned long long _Val, typename _IntType, typename... _Ints>
+    struct _Select_int_base<_Val, _IntType, _Ints...>
+    : __conditional_t<(_Val <= __gnu_cxx::__int_traits<_IntType>::__max),
+		      integral_constant<_IntType, (_IntType)_Val>,
+		      _Select_int_base<_Val, _Ints...>>
+    { };
+
+  template<unsigned long long _Val>
+    struct _Select_int_base<_Val>
+    { };
+
+  template<char... _Digs>
+    using _Select_int = typename _Select_int_base<
+	__parse_int::_Parse_int<_Digs...>::value,
+	unsigned char,
+	unsigned short,
+	unsigned int,
+	unsigned long,
+	unsigned long long
+      >::type;
+
+} // namespace __select_int
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif // C++14
+
+#endif // _GLIBCXX_PARSE_NUMBERS_H
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@postypes.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@postypes.h
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index 0000000000000000000000000000000000000000..9339a20a162bdc982ebc8302e61b1a0f9659b59c
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@postypes.h
@@ -0,0 +1,223 @@
+// Position types -*- C++ -*-
+
+// Copyright (C) 1997-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/postypes.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{iosfwd}
+ */
+
+//
+// ISO C++ 14882: 27.4.1 - Types
+// ISO C++ 14882: 27.4.3 - Template class fpos
+//
+
+#ifndef _GLIBCXX_POSTYPES_H
+#define _GLIBCXX_POSTYPES_H 1
+
+#pragma GCC system_header
+
+#include <cwchar> // For mbstate_t
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  // The types streamoff, streampos and wstreampos and the class
+  // template fpos<> are described in clauses 21.1.2, 21.1.3, 27.1.2,
+  // 27.2, 27.4.1, 27.4.3 and D.6. Despite all this verbiage, the
+  // behaviour of these types is mostly implementation defined or
+  // unspecified. The behaviour in this implementation is as noted
+  // below.
+
+  /**
+   *  @brief  Type used by fpos, char_traits<char>, and char_traits<wchar_t>.
+   *
+   *  In clauses 21.1.3.1 and 27.4.1 streamoff is described as an
+   *  implementation defined type.
+   *  Note: In versions of GCC up to and including GCC 3.3, streamoff
+   *  was typedef long.
+  */  
+#ifdef __INT64_TYPE__
+  typedef __INT64_TYPE__          streamoff;
+#else
+  typedef long long     streamoff;
+#endif
+
+  /// Integral type for I/O operation counts and buffer sizes.
+  typedef ptrdiff_t	streamsize; // Signed integral type
+
+  /**
+   *  @brief  Class representing stream positions.
+   *
+   *  The standard places no requirements upon the template parameter StateT.
+   *  In this implementation StateT must be DefaultConstructible,
+   *  CopyConstructible and Assignable.  The standard only requires that fpos
+   *  should contain a member of type StateT. In this implementation it also
+   *  contains an offset stored as a signed integer.
+   *
+   *  @param  StateT  Type passed to and returned from state().
+   */
+  template<typename _StateT>
+    class fpos
+    {
+    private:
+      streamoff	                _M_off;
+      _StateT			_M_state;
+
+    public:
+      // The standard doesn't require that fpos objects can be default
+      // constructed. This implementation provides a default
+      // constructor that initializes the offset to 0 and default
+      // constructs the state.
+      fpos()
+      : _M_off(0), _M_state() { }
+
+      // The standard requires that fpos objects can be constructed
+      // from streamoff objects using the constructor syntax, and
+      // fails to give any meaningful semantics. In this
+      // implementation implicit conversion is also allowed, and this
+      // constructor stores the streamoff as the offset and default
+      // constructs the state.
+      /// Construct position from offset.
+      fpos(streamoff __off)
+      : _M_off(__off), _M_state() { }
+
+#if __cplusplus >= 201103L
+      fpos(const fpos&) = default;
+      fpos& operator=(const fpos&) = default;
+      ~fpos() = default;
+#endif
+
+      /// Convert to streamoff.
+      operator streamoff() const { return _M_off; }
+
+      /// Remember the value of @a st.
+      void
+      state(_StateT __st)
+      { _M_state = __st; }
+
+      /// Return the last set value of @a st.
+      _StateT
+      state() const
+      { return _M_state; }
+
+      // The standard requires that this operator must be defined, but
+      // gives no semantics. In this implementation it just adds its
+      // argument to the stored offset and returns *this.
+      /// Add offset to this position.
+      fpos&
+      operator+=(streamoff __off)
+      {
+	_M_off += __off;
+	return *this;
+      }
+
+      // The standard requires that this operator must be defined, but
+      // gives no semantics. In this implementation it just subtracts
+      // its argument from the stored offset and returns *this.
+      /// Subtract offset from this position.
+      fpos&
+      operator-=(streamoff __off)
+      {
+	_M_off -= __off;
+	return *this;
+      }
+
+      // The standard requires that this operator must be defined, but
+      // defines its semantics only in terms of operator-. In this
+      // implementation it constructs a copy of *this, adds the
+      // argument to that copy using operator+= and then returns the
+      // copy.
+      /// Add position and offset.
+      fpos
+      operator+(streamoff __off) const
+      {
+	fpos __pos(*this);
+	__pos += __off;
+	return __pos;
+      }
+
+      // The standard requires that this operator must be defined, but
+      // defines its semantics only in terms of operator+. In this
+      // implementation it constructs a copy of *this, subtracts the
+      // argument from that copy using operator-= and then returns the
+      // copy.
+      /// Subtract offset from position.
+      fpos
+      operator-(streamoff __off) const
+      {
+	fpos __pos(*this);
+	__pos -= __off;
+	return __pos;
+      }
+
+      // The standard requires that this operator must be defined, but
+      // defines its semantics only in terms of operator+. In this
+      // implementation it returns the difference between the offset
+      // stored in *this and in the argument.
+      /// Subtract position to return offset.
+      streamoff
+      operator-(const fpos& __other) const
+      { return _M_off - __other._M_off; }
+    };
+
+  // The standard only requires that operator== must be an
+  // equivalence relation. In this implementation two fpos<StateT>
+  // objects belong to the same equivalence class if the contained
+  // offsets compare equal.
+  /// Test if equivalent to another position.
+  template<typename _StateT>
+    inline bool
+    operator==(const fpos<_StateT>& __lhs, const fpos<_StateT>& __rhs)
+    { return streamoff(__lhs) == streamoff(__rhs); }
+
+  template<typename _StateT>
+    inline bool
+    operator!=(const fpos<_StateT>& __lhs, const fpos<_StateT>& __rhs)
+    { return streamoff(__lhs) != streamoff(__rhs); }
+
+  // Clauses 21.1.3.1 and 21.1.3.2 describe streampos and wstreampos
+  // as implementation defined types, but clause 27.2 requires that
+  // they must both be typedefs for fpos<mbstate_t>
+  /// File position for char streams.
+  typedef fpos<mbstate_t> streampos;
+  /// File position for wchar_t streams.
+  typedef fpos<mbstate_t> wstreampos;
+
+#ifdef _GLIBCXX_USE_CHAR8_T
+  /// File position for char8_t streams.
+  typedef fpos<mbstate_t> u8streampos;
+#endif
+
+#if __cplusplus >= 201103L
+  /// File position for char16_t streams.
+  typedef fpos<mbstate_t> u16streampos;
+  /// File position for char32_t streams.
+  typedef fpos<mbstate_t> u32streampos;
+#endif
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@postypes.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@postypes.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@predefined_ops.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@predefined_ops.h
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index 0000000000000000000000000000000000000000..53c350323cb1cb5235449ae72be0c9d99f11368e
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@predefined_ops.h
@@ -0,0 +1,407 @@
+// Default predicates for internal use -*- C++ -*-
+
+// Copyright (C) 2013-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file predefined_ops.h
+ *  This is an internal header file, included by other library headers.
+ *  You should not attempt to use it directly. @headername{algorithm}
+ */
+
+#ifndef _GLIBCXX_PREDEFINED_OPS_H
+#define _GLIBCXX_PREDEFINED_OPS_H	1
+
+#include <bits/move.h>
+
+namespace __gnu_cxx
+{
+namespace __ops
+{
+  struct _Iter_less_iter
+  {
+    template<typename _Iterator1, typename _Iterator2>
+      _GLIBCXX14_CONSTEXPR
+      bool
+      operator()(_Iterator1 __it1, _Iterator2 __it2) const
+      { return *__it1 < *__it2; }
+  };
+
+  _GLIBCXX14_CONSTEXPR
+  inline _Iter_less_iter
+  __iter_less_iter()
+  { return _Iter_less_iter(); }
+
+  struct _Iter_less_val
+  {
+#if __cplusplus >= 201103L
+    constexpr _Iter_less_val() = default;
+#else
+    _Iter_less_val() { }
+#endif
+
+    _GLIBCXX20_CONSTEXPR
+    explicit
+    _Iter_less_val(_Iter_less_iter) { }
+
+    template<typename _Iterator, typename _Value>
+      _GLIBCXX20_CONSTEXPR
+      bool
+      operator()(_Iterator __it, _Value& __val) const
+      { return *__it < __val; }
+  };
+
+  _GLIBCXX20_CONSTEXPR
+  inline _Iter_less_val
+  __iter_less_val()
+  { return _Iter_less_val(); }
+
+  _GLIBCXX20_CONSTEXPR
+  inline _Iter_less_val
+  __iter_comp_val(_Iter_less_iter)
+  { return _Iter_less_val(); }
+
+  struct _Val_less_iter
+  {
+#if __cplusplus >= 201103L
+    constexpr _Val_less_iter() = default;
+#else
+    _Val_less_iter() { }
+#endif
+
+    _GLIBCXX20_CONSTEXPR
+    explicit
+    _Val_less_iter(_Iter_less_iter) { }
+
+    template<typename _Value, typename _Iterator>
+      _GLIBCXX20_CONSTEXPR
+      bool
+      operator()(_Value& __val, _Iterator __it) const
+      { return __val < *__it; }
+  };
+
+  _GLIBCXX20_CONSTEXPR
+  inline _Val_less_iter
+  __val_less_iter()
+  { return _Val_less_iter(); }
+
+  _GLIBCXX20_CONSTEXPR
+  inline _Val_less_iter
+  __val_comp_iter(_Iter_less_iter)
+  { return _Val_less_iter(); }
+
+  struct _Iter_equal_to_iter
+  {
+    template<typename _Iterator1, typename _Iterator2>
+      _GLIBCXX20_CONSTEXPR
+      bool
+      operator()(_Iterator1 __it1, _Iterator2 __it2) const
+      { return *__it1 == *__it2; }
+  };
+
+  _GLIBCXX20_CONSTEXPR
+  inline _Iter_equal_to_iter
+  __iter_equal_to_iter()
+  { return _Iter_equal_to_iter(); }
+
+  struct _Iter_equal_to_val
+  {
+    template<typename _Iterator, typename _Value>
+      _GLIBCXX20_CONSTEXPR
+      bool
+      operator()(_Iterator __it, _Value& __val) const
+      { return *__it == __val; }
+  };
+
+  _GLIBCXX20_CONSTEXPR
+  inline _Iter_equal_to_val
+  __iter_equal_to_val()
+  { return _Iter_equal_to_val(); }
+
+  _GLIBCXX20_CONSTEXPR
+  inline _Iter_equal_to_val
+  __iter_comp_val(_Iter_equal_to_iter)
+  { return _Iter_equal_to_val(); }
+
+  template<typename _Compare>
+    struct _Iter_comp_iter
+    {
+      _Compare _M_comp;
+
+      explicit _GLIBCXX14_CONSTEXPR
+      _Iter_comp_iter(_Compare __comp)
+	: _M_comp(_GLIBCXX_MOVE(__comp))
+      { }
+
+      template<typename _Iterator1, typename _Iterator2>
+        _GLIBCXX14_CONSTEXPR
+        bool
+        operator()(_Iterator1 __it1, _Iterator2 __it2)
+        { return bool(_M_comp(*__it1, *__it2)); }
+    };
+
+  template<typename _Compare>
+    _GLIBCXX14_CONSTEXPR
+    inline _Iter_comp_iter<_Compare>
+    __iter_comp_iter(_Compare __comp)
+    { return _Iter_comp_iter<_Compare>(_GLIBCXX_MOVE(__comp)); }
+
+  template<typename _Compare>
+    struct _Iter_comp_val
+    {
+      _Compare _M_comp;
+
+      _GLIBCXX20_CONSTEXPR
+      explicit
+      _Iter_comp_val(_Compare __comp)
+	: _M_comp(_GLIBCXX_MOVE(__comp))
+      { }
+
+      _GLIBCXX20_CONSTEXPR
+      explicit
+      _Iter_comp_val(const _Iter_comp_iter<_Compare>& __comp)
+	: _M_comp(__comp._M_comp)
+      { }
+
+#if __cplusplus >= 201103L
+      _GLIBCXX20_CONSTEXPR
+      explicit
+      _Iter_comp_val(_Iter_comp_iter<_Compare>&& __comp)
+	: _M_comp(std::move(__comp._M_comp))
+      { }
+#endif
+
+      template<typename _Iterator, typename _Value>
+	_GLIBCXX20_CONSTEXPR
+	bool
+	operator()(_Iterator __it, _Value& __val)
+	{ return bool(_M_comp(*__it, __val)); }
+    };
+
+  template<typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    inline _Iter_comp_val<_Compare>
+    __iter_comp_val(_Compare __comp)
+    { return _Iter_comp_val<_Compare>(_GLIBCXX_MOVE(__comp)); }
+
+  template<typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    inline _Iter_comp_val<_Compare>
+    __iter_comp_val(_Iter_comp_iter<_Compare> __comp)
+    { return _Iter_comp_val<_Compare>(_GLIBCXX_MOVE(__comp)); }
+
+  template<typename _Compare>
+    struct _Val_comp_iter
+    {
+      _Compare _M_comp;
+
+      _GLIBCXX20_CONSTEXPR
+      explicit
+      _Val_comp_iter(_Compare __comp)
+	: _M_comp(_GLIBCXX_MOVE(__comp))
+      { }
+
+      _GLIBCXX20_CONSTEXPR
+      explicit
+      _Val_comp_iter(const _Iter_comp_iter<_Compare>& __comp)
+	: _M_comp(__comp._M_comp)
+      { }
+
+#if __cplusplus >= 201103L
+      _GLIBCXX20_CONSTEXPR
+      explicit
+      _Val_comp_iter(_Iter_comp_iter<_Compare>&& __comp)
+	: _M_comp(std::move(__comp._M_comp))
+      { }
+#endif
+
+      template<typename _Value, typename _Iterator>
+	_GLIBCXX20_CONSTEXPR
+	bool
+	operator()(_Value& __val, _Iterator __it)
+	{ return bool(_M_comp(__val, *__it)); }
+    };
+
+  template<typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    inline _Val_comp_iter<_Compare>
+    __val_comp_iter(_Compare __comp)
+    { return _Val_comp_iter<_Compare>(_GLIBCXX_MOVE(__comp)); }
+
+  template<typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    inline _Val_comp_iter<_Compare>
+    __val_comp_iter(_Iter_comp_iter<_Compare> __comp)
+    { return _Val_comp_iter<_Compare>(_GLIBCXX_MOVE(__comp)); }
+
+  template<typename _Value>
+    struct _Iter_equals_val
+    {
+      _Value& _M_value;
+
+      _GLIBCXX20_CONSTEXPR
+      explicit
+      _Iter_equals_val(_Value& __value)
+	: _M_value(__value)
+      { }
+
+      template<typename _Iterator>
+	_GLIBCXX20_CONSTEXPR
+	bool
+	operator()(_Iterator __it)
+	{ return *__it == _M_value; }
+    };
+
+  template<typename _Value>
+    _GLIBCXX20_CONSTEXPR
+    inline _Iter_equals_val<_Value>
+    __iter_equals_val(_Value& __val)
+    { return _Iter_equals_val<_Value>(__val); }
+
+  template<typename _Iterator1>
+    struct _Iter_equals_iter
+    {
+      _Iterator1 _M_it1;
+
+      _GLIBCXX20_CONSTEXPR
+      explicit
+      _Iter_equals_iter(_Iterator1 __it1)
+	: _M_it1(__it1)
+      { }
+
+      template<typename _Iterator2>
+	_GLIBCXX20_CONSTEXPR
+	bool
+	operator()(_Iterator2 __it2)
+	{ return *__it2 == *_M_it1; }
+    };
+
+  template<typename _Iterator>
+    _GLIBCXX20_CONSTEXPR
+    inline _Iter_equals_iter<_Iterator>
+    __iter_comp_iter(_Iter_equal_to_iter, _Iterator __it)
+    { return _Iter_equals_iter<_Iterator>(__it); }
+
+  template<typename _Predicate>
+    struct _Iter_pred
+    {
+      _Predicate _M_pred;
+
+      _GLIBCXX20_CONSTEXPR
+      explicit
+      _Iter_pred(_Predicate __pred)
+	: _M_pred(_GLIBCXX_MOVE(__pred))
+      { }
+
+      template<typename _Iterator>
+	_GLIBCXX20_CONSTEXPR
+	bool
+	operator()(_Iterator __it)
+	{ return bool(_M_pred(*__it)); }
+    };
+
+  template<typename _Predicate>
+    _GLIBCXX20_CONSTEXPR
+    inline _Iter_pred<_Predicate>
+    __pred_iter(_Predicate __pred)
+    { return _Iter_pred<_Predicate>(_GLIBCXX_MOVE(__pred)); }
+
+  template<typename _Compare, typename _Value>
+    struct _Iter_comp_to_val
+    {
+      _Compare _M_comp;
+      _Value& _M_value;
+
+      _GLIBCXX20_CONSTEXPR
+      _Iter_comp_to_val(_Compare __comp, _Value& __value)
+	: _M_comp(_GLIBCXX_MOVE(__comp)), _M_value(__value)
+      { }
+
+      template<typename _Iterator>
+	_GLIBCXX20_CONSTEXPR
+	bool
+	operator()(_Iterator __it)
+	{ return bool(_M_comp(*__it, _M_value)); }
+    };
+
+  template<typename _Compare, typename _Value>
+    _Iter_comp_to_val<_Compare, _Value>
+    _GLIBCXX20_CONSTEXPR
+    __iter_comp_val(_Compare __comp, _Value &__val)
+    {
+      return _Iter_comp_to_val<_Compare, _Value>(_GLIBCXX_MOVE(__comp), __val);
+    }
+
+  template<typename _Compare, typename _Iterator1>
+    struct _Iter_comp_to_iter
+    {
+      _Compare _M_comp;
+      _Iterator1 _M_it1;
+
+      _GLIBCXX20_CONSTEXPR
+      _Iter_comp_to_iter(_Compare __comp, _Iterator1 __it1)
+	: _M_comp(_GLIBCXX_MOVE(__comp)), _M_it1(__it1)
+      { }
+
+      template<typename _Iterator2>
+	_GLIBCXX20_CONSTEXPR
+	bool
+	operator()(_Iterator2 __it2)
+	{ return bool(_M_comp(*__it2, *_M_it1)); }
+    };
+
+  template<typename _Compare, typename _Iterator>
+    _GLIBCXX20_CONSTEXPR
+    inline _Iter_comp_to_iter<_Compare, _Iterator>
+    __iter_comp_iter(_Iter_comp_iter<_Compare> __comp, _Iterator __it)
+    {
+      return _Iter_comp_to_iter<_Compare, _Iterator>(
+	  _GLIBCXX_MOVE(__comp._M_comp), __it);
+    }
+
+  template<typename _Predicate>
+    struct _Iter_negate
+    {
+      _Predicate _M_pred;
+
+      _GLIBCXX20_CONSTEXPR
+      explicit
+      _Iter_negate(_Predicate __pred)
+	: _M_pred(_GLIBCXX_MOVE(__pred))
+      { }
+
+      template<typename _Iterator>
+	_GLIBCXX20_CONSTEXPR
+	bool
+	operator()(_Iterator __it)
+	{ return !bool(_M_pred(*__it)); }
+    };
+
+  template<typename _Predicate>
+    _GLIBCXX20_CONSTEXPR
+    inline _Iter_negate<_Predicate>
+    __negate(_Iter_pred<_Predicate> __pred)
+    { return _Iter_negate<_Predicate>(_GLIBCXX_MOVE(__pred._M_pred)); }
+
+} // namespace __ops
+} // namespace __gnu_cxx
+
+#endif
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@ptr_traits.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@ptr_traits.h
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@@ -0,0 +1,287 @@
+// Pointer Traits -*- C++ -*-
+
+// Copyright (C) 2011-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/ptr_traits.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{memory}
+ */
+
+#ifndef _PTR_TRAITS_H
+#define _PTR_TRAITS_H 1
+
+#if __cplusplus >= 201103L
+
+#include <bits/move.h>
+
+#if __cplusplus > 201703L
+#include <concepts>
+# ifndef __cpp_lib_constexpr_memory
+// Defined to a newer value in bits/unique_ptr.h for C++23
+#  define __cpp_lib_constexpr_memory 201811L
+# endif
+namespace __gnu_debug { struct _Safe_iterator_base; }
+#endif
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  class __undefined;
+
+  // For a specialization `SomeTemplate<T, Types...>` the member `type` is T,
+  // otherwise `type` is `__undefined`.
+  template<typename _Tp>
+    struct __get_first_arg
+    { using type = __undefined; };
+
+  template<template<typename, typename...> class _SomeTemplate, typename _Tp,
+           typename... _Types>
+    struct __get_first_arg<_SomeTemplate<_Tp, _Types...>>
+    { using type = _Tp; };
+
+  // For a specialization `SomeTemplate<T, Args...>` and a type `U` the member
+  // `type` is `SomeTemplate<U, Args...>`, otherwise there is no member `type`.
+  template<typename _Tp, typename _Up>
+    struct __replace_first_arg
+    { };
+
+  template<template<typename, typename...> class _SomeTemplate, typename _Up,
+           typename _Tp, typename... _Types>
+    struct __replace_first_arg<_SomeTemplate<_Tp, _Types...>, _Up>
+    { using type = _SomeTemplate<_Up, _Types...>; };
+
+#if __cpp_concepts
+  // When concepts are supported detection of _Ptr::element_type is done
+  // by a requires-clause, so __ptr_traits_elem_t only needs to do this:
+  template<typename _Ptr>
+    using __ptr_traits_elem_t = typename __get_first_arg<_Ptr>::type;
+#else
+  // Detect the element type of a pointer-like type.
+  template<typename _Ptr, typename = void>
+    struct __ptr_traits_elem : __get_first_arg<_Ptr>
+    { };
+
+  // Use _Ptr::element_type if is a valid type.
+  template<typename _Ptr>
+    struct __ptr_traits_elem<_Ptr, __void_t<typename _Ptr::element_type>>
+    { using type = typename _Ptr::element_type; };
+
+  template<typename _Ptr>
+    using __ptr_traits_elem_t = typename __ptr_traits_elem<_Ptr>::type;
+#endif
+
+  // Define pointer_traits<P>::pointer_to.
+  template<typename _Ptr, typename _Elt, bool = is_void<_Elt>::value>
+    struct __ptr_traits_ptr_to
+    {
+      using pointer = _Ptr;
+      using element_type = _Elt;
+
+      /**
+       *  @brief  Obtain a pointer to an object
+       *  @param  __r  A reference to an object of type `element_type`
+       *  @return `pointer::pointer_to(__e)`
+       *  @pre `pointer::pointer_to(__e)` is a valid expression.
+      */
+      static pointer
+      pointer_to(element_type& __e)
+#if __cpp_lib_concepts
+      requires requires {
+	{ pointer::pointer_to(__e) } -> convertible_to<pointer>;
+      }
+#endif
+      { return pointer::pointer_to(__e); }
+    };
+
+  // Do not define pointer_traits<P>::pointer_to if element type is void.
+  template<typename _Ptr, typename _Elt>
+    struct __ptr_traits_ptr_to<_Ptr, _Elt, true>
+    { };
+
+  // Partial specialization defining pointer_traits<T*>::pointer_to(T&).
+  template<typename _Tp>
+    struct __ptr_traits_ptr_to<_Tp*, _Tp, false>
+    {
+      using pointer = _Tp*;
+      using element_type = _Tp;
+
+      /**
+       *  @brief  Obtain a pointer to an object
+       *  @param  __r  A reference to an object of type `element_type`
+       *  @return `addressof(__r)`
+      */
+      static _GLIBCXX20_CONSTEXPR pointer
+      pointer_to(element_type& __r) noexcept
+      { return std::addressof(__r); }
+    };
+
+  template<typename _Ptr, typename _Elt>
+    struct __ptr_traits_impl : __ptr_traits_ptr_to<_Ptr, _Elt>
+    {
+    private:
+      template<typename _Tp, typename = void>
+	struct __difference { using type = ptrdiff_t; };
+
+      template<typename _Tp>
+#if __cpp_concepts
+	requires requires { typename _Tp::difference_type; }
+	struct __difference<_Tp>
+#else
+	struct __difference<_Tp, __void_t<typename _Tp::difference_type>>
+#endif
+	{ using type = typename _Tp::difference_type; };
+
+      template<typename _Tp, typename _Up, typename = void>
+	struct __rebind : __replace_first_arg<_Tp, _Up> { };
+
+      template<typename _Tp, typename _Up>
+#if __cpp_concepts
+	requires requires { typename _Tp::template rebind<_Up>; }
+	struct __rebind<_Tp, _Up>
+#else
+	struct __rebind<_Tp, _Up, __void_t<typename _Tp::template rebind<_Up>>>
+#endif
+	{ using type = typename _Tp::template rebind<_Up>; };
+
+    public:
+      /// The pointer type.
+      using pointer = _Ptr;
+
+      /// The type pointed to.
+      using element_type = _Elt;
+
+      /// The type used to represent the difference between two pointers.
+      using difference_type = typename __difference<_Ptr>::type;
+
+      /// A pointer to a different type.
+      template<typename _Up>
+        using rebind = typename __rebind<_Ptr, _Up>::type;
+    };
+
+  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+  // 3545. std::pointer_traits should be SFINAE-friendly
+  template<typename _Ptr>
+    struct __ptr_traits_impl<_Ptr, __undefined>
+    { };
+
+  /**
+   * @brief  Uniform interface to all pointer-like types
+   * @ingroup pointer_abstractions
+   * @since C++11
+  */
+  template<typename _Ptr>
+    struct pointer_traits : __ptr_traits_impl<_Ptr, __ptr_traits_elem_t<_Ptr>>
+    { };
+
+#if __cpp_concepts
+  template<typename _Ptr> requires requires { typename _Ptr::element_type; }
+    struct pointer_traits<_Ptr>
+    : __ptr_traits_impl<_Ptr, typename _Ptr::element_type>
+    { };
+#endif
+
+  /**
+   * @brief  Partial specialization for built-in pointers.
+   * @ingroup pointer_abstractions
+   * @since C++11
+  */
+  template<typename _Tp>
+    struct pointer_traits<_Tp*> : __ptr_traits_ptr_to<_Tp*, _Tp>
+    {
+      /// The pointer type
+      typedef _Tp* pointer;
+      /// The type pointed to
+      typedef _Tp  element_type;
+      /// Type used to represent the difference between two pointers
+      typedef ptrdiff_t difference_type;
+      /// A pointer to a different type.
+      template<typename _Up> using rebind = _Up*;
+    };
+
+  /// Convenience alias for rebinding pointers.
+  template<typename _Ptr, typename _Tp>
+    using __ptr_rebind = typename pointer_traits<_Ptr>::template rebind<_Tp>;
+
+  template<typename _Tp>
+    constexpr _Tp*
+    __to_address(_Tp* __ptr) noexcept
+    {
+      static_assert(!std::is_function<_Tp>::value, "not a function pointer");
+      return __ptr;
+    }
+
+#if __cplusplus <= 201703L
+  template<typename _Ptr>
+    constexpr typename std::pointer_traits<_Ptr>::element_type*
+    __to_address(const _Ptr& __ptr)
+    { return std::__to_address(__ptr.operator->()); }
+#else
+  template<typename _Ptr>
+    constexpr auto
+    __to_address(const _Ptr& __ptr) noexcept
+    -> decltype(std::pointer_traits<_Ptr>::to_address(__ptr))
+    { return std::pointer_traits<_Ptr>::to_address(__ptr); }
+
+  template<typename _Ptr, typename... _None>
+    constexpr auto
+    __to_address(const _Ptr& __ptr, _None...) noexcept
+    {
+      if constexpr (is_base_of_v<__gnu_debug::_Safe_iterator_base, _Ptr>)
+	return std::__to_address(__ptr.base().operator->());
+      else
+	return std::__to_address(__ptr.operator->());
+    }
+
+#define __cpp_lib_to_address 201711L
+
+  /**
+   * @brief Obtain address referenced by a pointer to an object
+   * @param __ptr A pointer to an object
+   * @return @c __ptr
+   * @ingroup pointer_abstractions
+  */
+  template<typename _Tp>
+    constexpr _Tp*
+    to_address(_Tp* __ptr) noexcept
+    { return std::__to_address(__ptr); }
+
+  /**
+   * @brief Obtain address referenced by a pointer to an object
+   * @param __ptr A pointer to an object
+   * @return @c pointer_traits<_Ptr>::to_address(__ptr) if that expression is
+             well-formed, otherwise @c to_address(__ptr.operator->())
+   * @ingroup pointer_abstractions
+  */
+  template<typename _Ptr>
+    constexpr auto
+    to_address(const _Ptr& __ptr) noexcept
+    { return std::__to_address(__ptr); }
+#endif // C++2a
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif
+
+#endif
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@quoted_string.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@quoted_string.h
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@@ -0,0 +1,182 @@
+// Helpers for quoted stream manipulators -*- C++ -*-
+
+// Copyright (C) 2013-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/quoted_string.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{iomanip}
+ */
+
+#ifndef _GLIBCXX_QUOTED_STRING_H
+#define _GLIBCXX_QUOTED_STRING_H 1
+
+#pragma GCC system_header
+
+#if __cplusplus < 201103L
+# include <bits/c++0x_warning.h>
+#else
+#include <sstream>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  namespace __detail {
+    /**
+     * @brief Struct for delimited strings.
+     */
+    template<typename _String, typename _CharT>
+      struct _Quoted_string
+      {
+	static_assert(is_reference<_String>::value
+		   || is_pointer<_String>::value,
+		      "String type must be pointer or reference");
+
+	_Quoted_string(_String __str, _CharT __del, _CharT __esc)
+	: _M_string(__str), _M_delim{__del}, _M_escape{__esc}
+	{ }
+
+	_Quoted_string&
+	operator=(_Quoted_string&) = delete;
+
+	_String _M_string;
+	_CharT _M_delim;
+	_CharT _M_escape;
+      };
+
+#if __cplusplus >= 201703L
+    template<typename _CharT, typename _Traits>
+      struct _Quoted_string<basic_string_view<_CharT, _Traits>, _CharT>
+      {
+	_Quoted_string(basic_string_view<_CharT, _Traits> __str,
+		       _CharT __del, _CharT __esc)
+	: _M_string(__str), _M_delim{__del}, _M_escape{__esc}
+	{ }
+
+	_Quoted_string&
+	operator=(_Quoted_string&) = delete;
+
+	basic_string_view<_CharT, _Traits> _M_string;
+	_CharT _M_delim;
+	_CharT _M_escape;
+      };
+#endif // C++17
+
+    /**
+     * @brief Inserter for quoted strings.
+     *
+     *  _GLIBCXX_RESOLVE_LIB_DEFECTS
+     *  DR 2344 quoted()'s interaction with padding is unclear
+     */
+    template<typename _CharT, typename _Traits>
+      std::basic_ostream<_CharT, _Traits>&
+      operator<<(std::basic_ostream<_CharT, _Traits>& __os,
+		 const _Quoted_string<const _CharT*, _CharT>& __str)
+      {
+	std::basic_ostringstream<_CharT, _Traits> __ostr;
+	__ostr << __str._M_delim;
+	for (const _CharT* __c = __str._M_string; *__c; ++__c)
+	  {
+	    if (*__c == __str._M_delim || *__c == __str._M_escape)
+	      __ostr << __str._M_escape;
+	    __ostr << *__c;
+	  }
+	__ostr << __str._M_delim;
+
+	return __os << __ostr.str();
+      }
+
+    /**
+     * @brief Inserter for quoted strings.
+     *
+     *  _GLIBCXX_RESOLVE_LIB_DEFECTS
+     *  DR 2344 quoted()'s interaction with padding is unclear
+     */
+    template<typename _CharT, typename _Traits, typename _String>
+      std::basic_ostream<_CharT, _Traits>&
+      operator<<(std::basic_ostream<_CharT, _Traits>& __os,
+		 const _Quoted_string<_String, _CharT>& __str)
+      {
+	std::basic_ostringstream<_CharT, _Traits> __ostr;
+	__ostr << __str._M_delim;
+	for (auto __c : __str._M_string)
+	  {
+	    if (__c == __str._M_delim || __c == __str._M_escape)
+	      __ostr << __str._M_escape;
+	    __ostr << __c;
+	  }
+	__ostr << __str._M_delim;
+
+	return __os << __ostr.str();
+      }
+
+    /**
+     * @brief Extractor for delimited strings.
+     *        The left and right delimiters can be different.
+     */
+    template<typename _CharT, typename _Traits, typename _Alloc>
+      std::basic_istream<_CharT, _Traits>&
+      operator>>(std::basic_istream<_CharT, _Traits>& __is,
+		 const _Quoted_string<basic_string<_CharT, _Traits, _Alloc>&,
+				      _CharT>& __str)
+      {
+	_CharT __c;
+	__is >> __c;
+	if (!__is.good())
+	  return __is;
+	if (__c != __str._M_delim)
+	  {
+	    __is.unget();
+	    __is >> __str._M_string;
+	    return __is;
+	  }
+	__str._M_string.clear();
+	std::ios_base::fmtflags __flags
+	  = __is.flags(__is.flags() & ~std::ios_base::skipws);
+	do
+	  {
+	    __is >> __c;
+	    if (!__is.good())
+	      break;
+	    if (__c == __str._M_escape)
+	      {
+		__is >> __c;
+		if (!__is.good())
+		  break;
+	      }
+	    else if (__c == __str._M_delim)
+	      break;
+	    __str._M_string += __c;
+	  }
+	while (true);
+	__is.setf(__flags);
+
+	return __is;
+      }
+  } // namespace __detail
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif // C++11
+#endif /* _GLIBCXX_QUOTED_STRING_H */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@quoted_string.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@quoted_string.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@random.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@random.h
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@@ -0,0 +1,6114 @@
+// random number generation -*- C++ -*-
+
+// Copyright (C) 2009-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/**
+ * @file bits/random.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{random}
+ */
+
+#ifndef _RANDOM_H
+#define _RANDOM_H 1
+
+#include <vector>
+#include <bits/uniform_int_dist.h>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  // [26.4] Random number generation
+
+  /**
+   * @defgroup random Random Number Generation
+   * @ingroup numerics
+   *
+   * A facility for generating random numbers on selected distributions.
+   * @{
+   */
+
+  // std::uniform_random_bit_generator is defined in <bits/uniform_int_dist.h>
+
+  /**
+   * @brief A function template for converting the output of a (integral)
+   * uniform random number generator to a floatng point result in the range
+   * [0-1).
+   */
+  template<typename _RealType, size_t __bits,
+	   typename _UniformRandomNumberGenerator>
+    _RealType
+    generate_canonical(_UniformRandomNumberGenerator& __g);
+
+  /// @cond undocumented
+  // Implementation-space details.
+  namespace __detail
+  {
+    template<typename _UIntType, size_t __w,
+	     bool = __w < static_cast<size_t>
+			  (std::numeric_limits<_UIntType>::digits)>
+      struct _Shift
+      { static constexpr _UIntType __value = 0; };
+
+    template<typename _UIntType, size_t __w>
+      struct _Shift<_UIntType, __w, true>
+      { static constexpr _UIntType __value = _UIntType(1) << __w; };
+
+    template<int __s,
+	     int __which = ((__s <= __CHAR_BIT__ * sizeof (int))
+			    + (__s <= __CHAR_BIT__ * sizeof (long))
+			    + (__s <= __CHAR_BIT__ * sizeof (long long))
+			    /* assume long long no bigger than __int128 */
+			    + (__s <= 128))>
+      struct _Select_uint_least_t
+      {
+	static_assert(__which < 0, /* needs to be dependent */
+		      "sorry, would be too much trouble for a slow result");
+      };
+
+    template<int __s>
+      struct _Select_uint_least_t<__s, 4>
+      { using type = unsigned int; };
+
+    template<int __s>
+      struct _Select_uint_least_t<__s, 3>
+      { using type = unsigned long; };
+
+    template<int __s>
+      struct _Select_uint_least_t<__s, 2>
+      { using type = unsigned long long; };
+
+#if __SIZEOF_INT128__ > __SIZEOF_LONG_LONG__
+    template<int __s>
+      struct _Select_uint_least_t<__s, 1>
+      { __extension__ using type = unsigned __int128; };
+#endif
+
+    // Assume a != 0, a < m, c < m, x < m.
+    template<typename _Tp, _Tp __m, _Tp __a, _Tp __c,
+	     bool __big_enough = (!(__m & (__m - 1))
+				  || (_Tp(-1) - __c) / __a >= __m - 1),
+             bool __schrage_ok = __m % __a < __m / __a>
+      struct _Mod
+      {
+	static _Tp
+	__calc(_Tp __x)
+	{
+	  using _Tp2
+	    = typename _Select_uint_least_t<std::__lg(__a)
+					    + std::__lg(__m) + 2>::type;
+	  return static_cast<_Tp>((_Tp2(__a) * __x + __c) % __m);
+	}
+      };
+
+    // Schrage.
+    template<typename _Tp, _Tp __m, _Tp __a, _Tp __c>
+      struct _Mod<_Tp, __m, __a, __c, false, true>
+      {
+	static _Tp
+	__calc(_Tp __x);
+      };
+
+    // Special cases:
+    // - for m == 2^n or m == 0, unsigned integer overflow is safe.
+    // - a * (m - 1) + c fits in _Tp, there is no overflow.
+    template<typename _Tp, _Tp __m, _Tp __a, _Tp __c, bool __s>
+      struct _Mod<_Tp, __m, __a, __c, true, __s>
+      {
+	static _Tp
+	__calc(_Tp __x)
+	{
+	  _Tp __res = __a * __x + __c;
+	  if (__m)
+	    __res %= __m;
+	  return __res;
+	}
+      };
+
+    template<typename _Tp, _Tp __m, _Tp __a = 1, _Tp __c = 0>
+      inline _Tp
+      __mod(_Tp __x)
+      {
+	if _GLIBCXX17_CONSTEXPR (__a == 0)
+	  return __c;
+	else
+	  {
+	    // _Mod must not be instantiated with a == 0
+	    constexpr _Tp __a1 = __a ? __a : 1;
+	    return _Mod<_Tp, __m, __a1, __c>::__calc(__x);
+	  }
+      }
+
+    /*
+     * An adaptor class for converting the output of any Generator into
+     * the input for a specific Distribution.
+     */
+    template<typename _Engine, typename _DInputType>
+      struct _Adaptor
+      {
+	static_assert(std::is_floating_point<_DInputType>::value,
+		      "template argument must be a floating point type");
+
+      public:
+	_Adaptor(_Engine& __g)
+	: _M_g(__g) { }
+
+	_DInputType
+	min() const
+	{ return _DInputType(0); }
+
+	_DInputType
+	max() const
+	{ return _DInputType(1); }
+
+	/*
+	 * Converts a value generated by the adapted random number generator
+	 * into a value in the input domain for the dependent random number
+	 * distribution.
+	 */
+	_DInputType
+	operator()()
+	{
+	  return std::generate_canonical<_DInputType,
+	                            std::numeric_limits<_DInputType>::digits,
+	                            _Engine>(_M_g);
+	}
+
+      private:
+	_Engine& _M_g;
+      };
+
+    template<typename _Sseq>
+      using __seed_seq_generate_t = decltype(
+	  std::declval<_Sseq&>().generate(std::declval<uint_least32_t*>(),
+					  std::declval<uint_least32_t*>()));
+
+    // Detect whether _Sseq is a valid seed sequence for
+    // a random number engine _Engine with result type _Res.
+    template<typename _Sseq, typename _Engine, typename _Res,
+	     typename _GenerateCheck = __seed_seq_generate_t<_Sseq>>
+      using __is_seed_seq = __and_<
+        __not_<is_same<__remove_cvref_t<_Sseq>, _Engine>>,
+	is_unsigned<typename _Sseq::result_type>,
+	__not_<is_convertible<_Sseq, _Res>>
+      >;
+
+  } // namespace __detail
+  /// @endcond
+
+  /**
+   * @addtogroup random_generators Random Number Generators
+   * @ingroup random
+   *
+   * These classes define objects which provide random or pseudorandom
+   * numbers, either from a discrete or a continuous interval.  The
+   * random number generator supplied as a part of this library are
+   * all uniform random number generators which provide a sequence of
+   * random number uniformly distributed over their range.
+   *
+   * A number generator is a function object with an operator() that
+   * takes zero arguments and returns a number.
+   *
+   * A compliant random number generator must satisfy the following
+   * requirements.  <table border=1 cellpadding=10 cellspacing=0>
+   * <caption align=top>Random Number Generator Requirements</caption>
+   * <tr><td>To be documented.</td></tr> </table>
+   *
+   * @{
+   */
+
+  /**
+   * @brief A model of a linear congruential random number generator.
+   *
+   * A random number generator that produces pseudorandom numbers via
+   * linear function:
+   * @f[
+   *     x_{i+1}\leftarrow(ax_{i} + c) \bmod m 
+   * @f]
+   *
+   * The template parameter @p _UIntType must be an unsigned integral type
+   * large enough to store values up to (__m-1). If the template parameter
+   * @p __m is 0, the modulus @p __m used is
+   * std::numeric_limits<_UIntType>::max() plus 1. Otherwise, the template
+   * parameters @p __a and @p __c must be less than @p __m.
+   *
+   * The size of the state is @f$1@f$.
+   */
+  template<typename _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
+    class linear_congruential_engine
+    {
+      static_assert(std::is_unsigned<_UIntType>::value,
+		    "result_type must be an unsigned integral type");
+      static_assert(__m == 0u || (__a < __m && __c < __m),
+		    "template argument substituting __m out of bounds");
+
+      template<typename _Sseq>
+	using _If_seed_seq = typename enable_if<__detail::__is_seed_seq<
+	  _Sseq, linear_congruential_engine, _UIntType>::value>::type;
+
+    public:
+      /** The type of the generated random value. */
+      typedef _UIntType result_type;
+
+      /** The multiplier. */
+      static constexpr result_type multiplier   = __a;
+      /** An increment. */
+      static constexpr result_type increment    = __c;
+      /** The modulus. */
+      static constexpr result_type modulus      = __m;
+      static constexpr result_type default_seed = 1u;
+
+      /**
+       * @brief Constructs a %linear_congruential_engine random number
+       *        generator engine with seed 1.
+       */
+      linear_congruential_engine() : linear_congruential_engine(default_seed)
+      { }
+
+      /**
+       * @brief Constructs a %linear_congruential_engine random number
+       *        generator engine with seed @p __s.  The default seed value
+       *        is 1.
+       *
+       * @param __s The initial seed value.
+       */
+      explicit
+      linear_congruential_engine(result_type __s)
+      { seed(__s); }
+
+      /**
+       * @brief Constructs a %linear_congruential_engine random number
+       *        generator engine seeded from the seed sequence @p __q.
+       *
+       * @param __q the seed sequence.
+       */
+      template<typename _Sseq, typename = _If_seed_seq<_Sseq>>
+        explicit
+        linear_congruential_engine(_Sseq& __q)
+        { seed(__q); }
+
+      /**
+       * @brief Reseeds the %linear_congruential_engine random number generator
+       *        engine sequence to the seed @p __s.
+       *
+       * @param __s The new seed.
+       */
+      void
+      seed(result_type __s = default_seed);
+
+      /**
+       * @brief Reseeds the %linear_congruential_engine random number generator
+       *        engine
+       * sequence using values from the seed sequence @p __q.
+       *
+       * @param __q the seed sequence.
+       */
+      template<typename _Sseq>
+        _If_seed_seq<_Sseq>
+        seed(_Sseq& __q);
+
+      /**
+       * @brief Gets the smallest possible value in the output range.
+       *
+       * The minimum depends on the @p __c parameter: if it is zero, the
+       * minimum generated must be > 0, otherwise 0 is allowed.
+       */
+      static constexpr result_type
+      min()
+      { return __c == 0u ? 1u : 0u; }
+
+      /**
+       * @brief Gets the largest possible value in the output range.
+       */
+      static constexpr result_type
+      max()
+      { return __m - 1u; }
+
+      /**
+       * @brief Discard a sequence of random numbers.
+       */
+      void
+      discard(unsigned long long __z)
+      {
+	for (; __z != 0ULL; --__z)
+	  (*this)();
+      }
+
+      /**
+       * @brief Gets the next random number in the sequence.
+       */
+      result_type
+      operator()()
+      {
+	_M_x = __detail::__mod<_UIntType, __m, __a, __c>(_M_x);
+	return _M_x;
+      }
+
+      /**
+       * @brief Compares two linear congruential random number generator
+       * objects of the same type for equality.
+       *
+       * @param __lhs A linear congruential random number generator object.
+       * @param __rhs Another linear congruential random number generator
+       *              object.
+       *
+       * @returns true if the infinite sequences of generated values
+       *          would be equal, false otherwise.
+       */
+      friend bool
+      operator==(const linear_congruential_engine& __lhs,
+		 const linear_congruential_engine& __rhs)
+      { return __lhs._M_x == __rhs._M_x; }
+
+      /**
+       * @brief Writes the textual representation of the state x(i) of x to
+       *        @p __os.
+       *
+       * @param __os  The output stream.
+       * @param __lcr A % linear_congruential_engine random number generator.
+       * @returns __os.
+       */
+      template<typename _UIntType1, _UIntType1 __a1, _UIntType1 __c1,
+	       _UIntType1 __m1, typename _CharT, typename _Traits>
+	friend std::basic_ostream<_CharT, _Traits>&
+	operator<<(std::basic_ostream<_CharT, _Traits>& __os,
+		   const std::linear_congruential_engine<_UIntType1,
+		   __a1, __c1, __m1>& __lcr);
+
+      /**
+       * @brief Sets the state of the engine by reading its textual
+       *        representation from @p __is.
+       *
+       * The textual representation must have been previously written using
+       * an output stream whose imbued locale and whose type's template
+       * specialization arguments _CharT and _Traits were the same as those
+       * of @p __is.
+       *
+       * @param __is  The input stream.
+       * @param __lcr A % linear_congruential_engine random number generator.
+       * @returns __is.
+       */
+      template<typename _UIntType1, _UIntType1 __a1, _UIntType1 __c1,
+	       _UIntType1 __m1, typename _CharT, typename _Traits>
+	friend std::basic_istream<_CharT, _Traits>&
+	operator>>(std::basic_istream<_CharT, _Traits>& __is,
+		   std::linear_congruential_engine<_UIntType1, __a1,
+		   __c1, __m1>& __lcr);
+
+    private:
+      _UIntType _M_x;
+    };
+
+  /**
+   * @brief Compares two linear congruential random number generator
+   * objects of the same type for inequality.
+   *
+   * @param __lhs A linear congruential random number generator object.
+   * @param __rhs Another linear congruential random number generator
+   *              object.
+   *
+   * @returns true if the infinite sequences of generated values
+   *          would be different, false otherwise.
+   */
+  template<typename _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
+    inline bool
+    operator!=(const std::linear_congruential_engine<_UIntType, __a,
+	       __c, __m>& __lhs,
+	       const std::linear_congruential_engine<_UIntType, __a,
+	       __c, __m>& __rhs)
+    { return !(__lhs == __rhs); }
+
+
+  /**
+   * A generalized feedback shift register discrete random number generator.
+   *
+   * This algorithm avoids multiplication and division and is designed to be
+   * friendly to a pipelined architecture.  If the parameters are chosen
+   * correctly, this generator will produce numbers with a very long period and
+   * fairly good apparent entropy, although still not cryptographically strong.
+   *
+   * The best way to use this generator is with the predefined mt19937 class.
+   *
+   * This algorithm was originally invented by Makoto Matsumoto and
+   * Takuji Nishimura.
+   *
+   * @tparam __w  Word size, the number of bits in each element of 
+   *              the state vector.
+   * @tparam __n  The degree of recursion.
+   * @tparam __m  The period parameter.
+   * @tparam __r  The separation point bit index.
+   * @tparam __a  The last row of the twist matrix.
+   * @tparam __u  The first right-shift tempering matrix parameter.
+   * @tparam __d  The first right-shift tempering matrix mask.
+   * @tparam __s  The first left-shift tempering matrix parameter.
+   * @tparam __b  The first left-shift tempering matrix mask.
+   * @tparam __t  The second left-shift tempering matrix parameter.
+   * @tparam __c  The second left-shift tempering matrix mask.
+   * @tparam __l  The second right-shift tempering matrix parameter.
+   * @tparam __f  Initialization multiplier.
+   */
+  template<typename _UIntType, size_t __w,
+	   size_t __n, size_t __m, size_t __r,
+	   _UIntType __a, size_t __u, _UIntType __d, size_t __s,
+	   _UIntType __b, size_t __t,
+	   _UIntType __c, size_t __l, _UIntType __f>
+    class mersenne_twister_engine
+    {
+      static_assert(std::is_unsigned<_UIntType>::value,
+		    "result_type must be an unsigned integral type");
+      static_assert(1u <= __m && __m <= __n,
+		    "template argument substituting __m out of bounds");
+      static_assert(__r <= __w, "template argument substituting "
+		    "__r out of bound");
+      static_assert(__u <= __w, "template argument substituting "
+		    "__u out of bound");
+      static_assert(__s <= __w, "template argument substituting "
+		    "__s out of bound");
+      static_assert(__t <= __w, "template argument substituting "
+		    "__t out of bound");
+      static_assert(__l <= __w, "template argument substituting "
+		    "__l out of bound");
+      static_assert(__w <= std::numeric_limits<_UIntType>::digits,
+		    "template argument substituting __w out of bound");
+      static_assert(__a <= (__detail::_Shift<_UIntType, __w>::__value - 1),
+		    "template argument substituting __a out of bound");
+      static_assert(__b <= (__detail::_Shift<_UIntType, __w>::__value - 1),
+		    "template argument substituting __b out of bound");
+      static_assert(__c <= (__detail::_Shift<_UIntType, __w>::__value - 1),
+		    "template argument substituting __c out of bound");
+      static_assert(__d <= (__detail::_Shift<_UIntType, __w>::__value - 1),
+		    "template argument substituting __d out of bound");
+      static_assert(__f <= (__detail::_Shift<_UIntType, __w>::__value - 1),
+		    "template argument substituting __f out of bound");
+
+      template<typename _Sseq>
+	using _If_seed_seq = typename enable_if<__detail::__is_seed_seq<
+	  _Sseq, mersenne_twister_engine, _UIntType>::value>::type;
+
+    public:
+      /** The type of the generated random value. */
+      typedef _UIntType result_type;
+
+      // parameter values
+      static constexpr size_t      word_size                 = __w;
+      static constexpr size_t      state_size                = __n;
+      static constexpr size_t      shift_size                = __m;
+      static constexpr size_t      mask_bits                 = __r;
+      static constexpr result_type xor_mask                  = __a;
+      static constexpr size_t      tempering_u               = __u;
+      static constexpr result_type tempering_d               = __d;
+      static constexpr size_t      tempering_s               = __s;
+      static constexpr result_type tempering_b               = __b;
+      static constexpr size_t      tempering_t               = __t;
+      static constexpr result_type tempering_c               = __c;
+      static constexpr size_t      tempering_l               = __l;
+      static constexpr result_type initialization_multiplier = __f;
+      static constexpr result_type default_seed = 5489u;
+
+      // constructors and member functions
+
+      mersenne_twister_engine() : mersenne_twister_engine(default_seed) { }
+
+      explicit
+      mersenne_twister_engine(result_type __sd)
+      { seed(__sd); }
+
+      /**
+       * @brief Constructs a %mersenne_twister_engine random number generator
+       *        engine seeded from the seed sequence @p __q.
+       *
+       * @param __q the seed sequence.
+       */
+      template<typename _Sseq, typename = _If_seed_seq<_Sseq>>
+        explicit
+        mersenne_twister_engine(_Sseq& __q)
+        { seed(__q); }
+
+      void
+      seed(result_type __sd = default_seed);
+
+      template<typename _Sseq>
+        _If_seed_seq<_Sseq>
+        seed(_Sseq& __q);
+
+      /**
+       * @brief Gets the smallest possible value in the output range.
+       */
+      static constexpr result_type
+      min()
+      { return 0; }
+
+      /**
+       * @brief Gets the largest possible value in the output range.
+       */
+      static constexpr result_type
+      max()
+      { return __detail::_Shift<_UIntType, __w>::__value - 1; }
+
+      /**
+       * @brief Discard a sequence of random numbers.
+       */
+      void
+      discard(unsigned long long __z);
+
+      result_type
+      operator()();
+
+      /**
+       * @brief Compares two % mersenne_twister_engine random number generator
+       *        objects of the same type for equality.
+       *
+       * @param __lhs A % mersenne_twister_engine random number generator
+       *              object.
+       * @param __rhs Another % mersenne_twister_engine random number
+       *              generator object.
+       *
+       * @returns true if the infinite sequences of generated values
+       *          would be equal, false otherwise.
+       */
+      friend bool
+      operator==(const mersenne_twister_engine& __lhs,
+		 const mersenne_twister_engine& __rhs)
+      { return (std::equal(__lhs._M_x, __lhs._M_x + state_size, __rhs._M_x)
+		&& __lhs._M_p == __rhs._M_p); }
+
+      /**
+       * @brief Inserts the current state of a % mersenne_twister_engine
+       *        random number generator engine @p __x into the output stream
+       *        @p __os.
+       *
+       * @param __os An output stream.
+       * @param __x  A % mersenne_twister_engine random number generator
+       *             engine.
+       *
+       * @returns The output stream with the state of @p __x inserted or in
+       * an error state.
+       */
+      template<typename _UIntType1,
+	       size_t __w1, size_t __n1,
+	       size_t __m1, size_t __r1,
+	       _UIntType1 __a1, size_t __u1,
+	       _UIntType1 __d1, size_t __s1,
+	       _UIntType1 __b1, size_t __t1,
+	       _UIntType1 __c1, size_t __l1, _UIntType1 __f1,
+	       typename _CharT, typename _Traits>
+	friend std::basic_ostream<_CharT, _Traits>&
+	operator<<(std::basic_ostream<_CharT, _Traits>& __os,
+		   const std::mersenne_twister_engine<_UIntType1, __w1, __n1,
+		   __m1, __r1, __a1, __u1, __d1, __s1, __b1, __t1, __c1,
+		   __l1, __f1>& __x);
+
+      /**
+       * @brief Extracts the current state of a % mersenne_twister_engine
+       *        random number generator engine @p __x from the input stream
+       *        @p __is.
+       *
+       * @param __is An input stream.
+       * @param __x  A % mersenne_twister_engine random number generator
+       *             engine.
+       *
+       * @returns The input stream with the state of @p __x extracted or in
+       * an error state.
+       */
+      template<typename _UIntType1,
+	       size_t __w1, size_t __n1,
+	       size_t __m1, size_t __r1,
+	       _UIntType1 __a1, size_t __u1,
+	       _UIntType1 __d1, size_t __s1,
+	       _UIntType1 __b1, size_t __t1,
+	       _UIntType1 __c1, size_t __l1, _UIntType1 __f1,
+	       typename _CharT, typename _Traits>
+	friend std::basic_istream<_CharT, _Traits>&
+	operator>>(std::basic_istream<_CharT, _Traits>& __is,
+		   std::mersenne_twister_engine<_UIntType1, __w1, __n1, __m1,
+		   __r1, __a1, __u1, __d1, __s1, __b1, __t1, __c1,
+		   __l1, __f1>& __x);
+
+    private:
+      void _M_gen_rand();
+
+      _UIntType _M_x[state_size];
+      size_t    _M_p;
+    };
+
+  /**
+   * @brief Compares two % mersenne_twister_engine random number generator
+   *        objects of the same type for inequality.
+   *
+   * @param __lhs A % mersenne_twister_engine random number generator
+   *              object.
+   * @param __rhs Another % mersenne_twister_engine random number
+   *              generator object.
+   *
+   * @returns true if the infinite sequences of generated values
+   *          would be different, false otherwise.
+   */
+  template<typename _UIntType, size_t __w,
+	   size_t __n, size_t __m, size_t __r,
+	   _UIntType __a, size_t __u, _UIntType __d, size_t __s,
+	   _UIntType __b, size_t __t,
+	   _UIntType __c, size_t __l, _UIntType __f>
+    inline bool
+    operator!=(const std::mersenne_twister_engine<_UIntType, __w, __n, __m,
+	       __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>& __lhs,
+	       const std::mersenne_twister_engine<_UIntType, __w, __n, __m,
+	       __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>& __rhs)
+    { return !(__lhs == __rhs); }
+
+
+  /**
+   * @brief The Marsaglia-Zaman generator.
+   *
+   * This is a model of a Generalized Fibonacci discrete random number
+   * generator, sometimes referred to as the SWC generator.
+   *
+   * A discrete random number generator that produces pseudorandom
+   * numbers using:
+   * @f[
+   *     x_{i}\leftarrow(x_{i - s} - x_{i - r} - carry_{i-1}) \bmod m 
+   * @f]
+   *
+   * The size of the state is @f$r@f$
+   * and the maximum period of the generator is @f$(m^r - m^s - 1)@f$.
+   */
+  template<typename _UIntType, size_t __w, size_t __s, size_t __r>
+    class subtract_with_carry_engine
+    {
+      static_assert(std::is_unsigned<_UIntType>::value,
+		    "result_type must be an unsigned integral type");
+      static_assert(0u < __s && __s < __r,
+		    "0 < s < r");
+      static_assert(0u < __w && __w <= std::numeric_limits<_UIntType>::digits,
+		    "template argument substituting __w out of bounds");
+
+      template<typename _Sseq>
+	using _If_seed_seq = typename enable_if<__detail::__is_seed_seq<
+	  _Sseq, subtract_with_carry_engine, _UIntType>::value>::type;
+
+    public:
+      /** The type of the generated random value. */
+      typedef _UIntType result_type;
+
+      // parameter values
+      static constexpr size_t      word_size    = __w;
+      static constexpr size_t      short_lag    = __s;
+      static constexpr size_t      long_lag     = __r;
+      static constexpr result_type default_seed = 19780503u;
+
+      subtract_with_carry_engine() : subtract_with_carry_engine(default_seed)
+      { }
+
+      /**
+       * @brief Constructs an explicitly seeded %subtract_with_carry_engine
+       *        random number generator.
+       */
+      explicit
+      subtract_with_carry_engine(result_type __sd)
+      { seed(__sd); }
+
+      /**
+       * @brief Constructs a %subtract_with_carry_engine random number engine
+       *        seeded from the seed sequence @p __q.
+       *
+       * @param __q the seed sequence.
+       */
+      template<typename _Sseq, typename = _If_seed_seq<_Sseq>>
+        explicit
+        subtract_with_carry_engine(_Sseq& __q)
+        { seed(__q); }
+
+      /**
+       * @brief Seeds the initial state @f$x_0@f$ of the random number
+       *        generator.
+       *
+       * N1688[4.19] modifies this as follows.  If @p __value == 0,
+       * sets value to 19780503.  In any case, with a linear
+       * congruential generator lcg(i) having parameters @f$ m_{lcg} =
+       * 2147483563, a_{lcg} = 40014, c_{lcg} = 0, and lcg(0) = value
+       * @f$, sets @f$ x_{-r} \dots x_{-1} @f$ to @f$ lcg(1) \bmod m
+       * \dots lcg(r) \bmod m @f$ respectively.  If @f$ x_{-1} = 0 @f$
+       * set carry to 1, otherwise sets carry to 0.
+       */
+      void
+      seed(result_type __sd = default_seed);
+
+      /**
+       * @brief Seeds the initial state @f$x_0@f$ of the
+       * % subtract_with_carry_engine random number generator.
+       */
+      template<typename _Sseq>
+	_If_seed_seq<_Sseq>
+        seed(_Sseq& __q);
+
+      /**
+       * @brief Gets the inclusive minimum value of the range of random
+       * integers returned by this generator.
+       */
+      static constexpr result_type
+      min()
+      { return 0; }
+
+      /**
+       * @brief Gets the inclusive maximum value of the range of random
+       * integers returned by this generator.
+       */
+      static constexpr result_type
+      max()
+      { return __detail::_Shift<_UIntType, __w>::__value - 1; }
+
+      /**
+       * @brief Discard a sequence of random numbers.
+       */
+      void
+      discard(unsigned long long __z)
+      {
+	for (; __z != 0ULL; --__z)
+	  (*this)();
+      }
+
+      /**
+       * @brief Gets the next random number in the sequence.
+       */
+      result_type
+      operator()();
+
+      /**
+       * @brief Compares two % subtract_with_carry_engine random number
+       *        generator objects of the same type for equality.
+       *
+       * @param __lhs A % subtract_with_carry_engine random number generator
+       *              object.
+       * @param __rhs Another % subtract_with_carry_engine random number
+       *              generator object.
+       *
+       * @returns true if the infinite sequences of generated values
+       *          would be equal, false otherwise.
+      */
+      friend bool
+      operator==(const subtract_with_carry_engine& __lhs,
+		 const subtract_with_carry_engine& __rhs)
+      { return (std::equal(__lhs._M_x, __lhs._M_x + long_lag, __rhs._M_x)
+		&& __lhs._M_carry == __rhs._M_carry
+		&& __lhs._M_p == __rhs._M_p); }
+
+      /**
+       * @brief Inserts the current state of a % subtract_with_carry_engine
+       *        random number generator engine @p __x into the output stream
+       *        @p __os.
+       *
+       * @param __os An output stream.
+       * @param __x  A % subtract_with_carry_engine random number generator
+       *             engine.
+       *
+       * @returns The output stream with the state of @p __x inserted or in
+       * an error state.
+       */
+      template<typename _UIntType1, size_t __w1, size_t __s1, size_t __r1,
+	       typename _CharT, typename _Traits>
+	friend std::basic_ostream<_CharT, _Traits>&
+	operator<<(std::basic_ostream<_CharT, _Traits>& __os,
+		   const std::subtract_with_carry_engine<_UIntType1, __w1,
+		   __s1, __r1>& __x);
+
+      /**
+       * @brief Extracts the current state of a % subtract_with_carry_engine
+       *        random number generator engine @p __x from the input stream
+       *        @p __is.
+       *
+       * @param __is An input stream.
+       * @param __x  A % subtract_with_carry_engine random number generator
+       *             engine.
+       *
+       * @returns The input stream with the state of @p __x extracted or in
+       * an error state.
+       */
+      template<typename _UIntType1, size_t __w1, size_t __s1, size_t __r1,
+	       typename _CharT, typename _Traits>
+	friend std::basic_istream<_CharT, _Traits>&
+	operator>>(std::basic_istream<_CharT, _Traits>& __is,
+		   std::subtract_with_carry_engine<_UIntType1, __w1,
+		   __s1, __r1>& __x);
+
+    private:
+      /// The state of the generator.  This is a ring buffer.
+      _UIntType  _M_x[long_lag];
+      _UIntType  _M_carry;		///< The carry
+      size_t     _M_p;			///< Current index of x(i - r).
+    };
+
+  /**
+   * @brief Compares two % subtract_with_carry_engine random number
+   *        generator objects of the same type for inequality.
+   *
+   * @param __lhs A % subtract_with_carry_engine random number generator
+   *              object.
+   * @param __rhs Another % subtract_with_carry_engine random number
+   *              generator object.
+   *
+   * @returns true if the infinite sequences of generated values
+   *          would be different, false otherwise.
+   */
+  template<typename _UIntType, size_t __w, size_t __s, size_t __r>
+    inline bool
+    operator!=(const std::subtract_with_carry_engine<_UIntType, __w,
+	       __s, __r>& __lhs,
+	       const std::subtract_with_carry_engine<_UIntType, __w,
+	       __s, __r>& __rhs)
+    { return !(__lhs == __rhs); }
+
+
+  /**
+   * Produces random numbers from some base engine by discarding blocks of
+   * data.
+   *
+   * 0 <= @p __r <= @p __p
+   */
+  template<typename _RandomNumberEngine, size_t __p, size_t __r>
+    class discard_block_engine
+    {
+      static_assert(1 <= __r && __r <= __p,
+		    "template argument substituting __r out of bounds");
+
+    public:
+      /** The type of the generated random value. */
+      typedef typename _RandomNumberEngine::result_type result_type;
+
+      template<typename _Sseq>
+	using _If_seed_seq = typename enable_if<__detail::__is_seed_seq<
+	  _Sseq, discard_block_engine, result_type>::value>::type;
+
+      // parameter values
+      static constexpr size_t block_size = __p;
+      static constexpr size_t used_block = __r;
+
+      /**
+       * @brief Constructs a default %discard_block_engine engine.
+       *
+       * The underlying engine is default constructed as well.
+       */
+      discard_block_engine()
+      : _M_b(), _M_n(0) { }
+
+      /**
+       * @brief Copy constructs a %discard_block_engine engine.
+       *
+       * Copies an existing base class random number generator.
+       * @param __rng An existing (base class) engine object.
+       */
+      explicit
+      discard_block_engine(const _RandomNumberEngine& __rng)
+      : _M_b(__rng), _M_n(0) { }
+
+      /**
+       * @brief Move constructs a %discard_block_engine engine.
+       *
+       * Copies an existing base class random number generator.
+       * @param __rng An existing (base class) engine object.
+       */
+      explicit
+      discard_block_engine(_RandomNumberEngine&& __rng)
+      : _M_b(std::move(__rng)), _M_n(0) { }
+
+      /**
+       * @brief Seed constructs a %discard_block_engine engine.
+       *
+       * Constructs the underlying generator engine seeded with @p __s.
+       * @param __s A seed value for the base class engine.
+       */
+      explicit
+      discard_block_engine(result_type __s)
+      : _M_b(__s), _M_n(0) { }
+
+      /**
+       * @brief Generator construct a %discard_block_engine engine.
+       *
+       * @param __q A seed sequence.
+       */
+      template<typename _Sseq, typename = _If_seed_seq<_Sseq>>
+        explicit
+        discard_block_engine(_Sseq& __q)
+	: _M_b(__q), _M_n(0)
+        { }
+
+      /**
+       * @brief Reseeds the %discard_block_engine object with the default
+       *        seed for the underlying base class generator engine.
+       */
+      void
+      seed()
+      {
+	_M_b.seed();
+	_M_n = 0;
+      }
+
+      /**
+       * @brief Reseeds the %discard_block_engine object with the default
+       *        seed for the underlying base class generator engine.
+       */
+      void
+      seed(result_type __s)
+      {
+	_M_b.seed(__s);
+	_M_n = 0;
+      }
+
+      /**
+       * @brief Reseeds the %discard_block_engine object with the given seed
+       *        sequence.
+       * @param __q A seed generator function.
+       */
+      template<typename _Sseq>
+        _If_seed_seq<_Sseq>
+        seed(_Sseq& __q)
+        {
+	  _M_b.seed(__q);
+	  _M_n = 0;
+	}
+
+      /**
+       * @brief Gets a const reference to the underlying generator engine
+       *        object.
+       */
+      const _RandomNumberEngine&
+      base() const noexcept
+      { return _M_b; }
+
+      /**
+       * @brief Gets the minimum value in the generated random number range.
+       */
+      static constexpr result_type
+      min()
+      { return _RandomNumberEngine::min(); }
+
+      /**
+       * @brief Gets the maximum value in the generated random number range.
+       */
+      static constexpr result_type
+      max()
+      { return _RandomNumberEngine::max(); }
+
+      /**
+       * @brief Discard a sequence of random numbers.
+       */
+      void
+      discard(unsigned long long __z)
+      {
+	for (; __z != 0ULL; --__z)
+	  (*this)();
+      }
+
+      /**
+       * @brief Gets the next value in the generated random number sequence.
+       */
+      result_type
+      operator()();
+
+      /**
+       * @brief Compares two %discard_block_engine random number generator
+       *        objects of the same type for equality.
+       *
+       * @param __lhs A %discard_block_engine random number generator object.
+       * @param __rhs Another %discard_block_engine random number generator
+       *              object.
+       *
+       * @returns true if the infinite sequences of generated values
+       *          would be equal, false otherwise.
+       */
+      friend bool
+      operator==(const discard_block_engine& __lhs,
+		 const discard_block_engine& __rhs)
+      { return __lhs._M_b == __rhs._M_b && __lhs._M_n == __rhs._M_n; }
+
+      /**
+       * @brief Inserts the current state of a %discard_block_engine random
+       *        number generator engine @p __x into the output stream
+       *        @p __os.
+       *
+       * @param __os An output stream.
+       * @param __x  A %discard_block_engine random number generator engine.
+       *
+       * @returns The output stream with the state of @p __x inserted or in
+       * an error state.
+       */
+      template<typename _RandomNumberEngine1, size_t __p1, size_t __r1,
+	       typename _CharT, typename _Traits>
+	friend std::basic_ostream<_CharT, _Traits>&
+	operator<<(std::basic_ostream<_CharT, _Traits>& __os,
+		   const std::discard_block_engine<_RandomNumberEngine1,
+		   __p1, __r1>& __x);
+
+      /**
+       * @brief Extracts the current state of a % subtract_with_carry_engine
+       *        random number generator engine @p __x from the input stream
+       *        @p __is.
+       *
+       * @param __is An input stream.
+       * @param __x  A %discard_block_engine random number generator engine.
+       *
+       * @returns The input stream with the state of @p __x extracted or in
+       * an error state.
+       */
+      template<typename _RandomNumberEngine1, size_t __p1, size_t __r1,
+	       typename _CharT, typename _Traits>
+	friend std::basic_istream<_CharT, _Traits>&
+	operator>>(std::basic_istream<_CharT, _Traits>& __is,
+		   std::discard_block_engine<_RandomNumberEngine1,
+		   __p1, __r1>& __x);
+
+    private:
+      _RandomNumberEngine _M_b;
+      size_t _M_n;
+    };
+
+  /**
+   * @brief Compares two %discard_block_engine random number generator
+   *        objects of the same type for inequality.
+   *
+   * @param __lhs A %discard_block_engine random number generator object.
+   * @param __rhs Another %discard_block_engine random number generator
+   *              object.
+   *
+   * @returns true if the infinite sequences of generated values
+   *          would be different, false otherwise.
+   */
+  template<typename _RandomNumberEngine, size_t __p, size_t __r>
+    inline bool
+    operator!=(const std::discard_block_engine<_RandomNumberEngine, __p,
+	       __r>& __lhs,
+	       const std::discard_block_engine<_RandomNumberEngine, __p,
+	       __r>& __rhs)
+    { return !(__lhs == __rhs); }
+
+
+  /**
+   * Produces random numbers by combining random numbers from some base
+   * engine to produce random numbers with a specified number of bits @p __w.
+   */
+  template<typename _RandomNumberEngine, size_t __w, typename _UIntType>
+    class independent_bits_engine
+    {
+      static_assert(std::is_unsigned<_UIntType>::value,
+		    "result_type must be an unsigned integral type");
+      static_assert(0u < __w && __w <= std::numeric_limits<_UIntType>::digits,
+		    "template argument substituting __w out of bounds");
+
+      template<typename _Sseq>
+	using _If_seed_seq = typename enable_if<__detail::__is_seed_seq<
+	  _Sseq, independent_bits_engine, _UIntType>::value>::type;
+
+    public:
+      /** The type of the generated random value. */
+      typedef _UIntType result_type;
+
+      /**
+       * @brief Constructs a default %independent_bits_engine engine.
+       *
+       * The underlying engine is default constructed as well.
+       */
+      independent_bits_engine()
+      : _M_b() { }
+
+      /**
+       * @brief Copy constructs a %independent_bits_engine engine.
+       *
+       * Copies an existing base class random number generator.
+       * @param __rng An existing (base class) engine object.
+       */
+      explicit
+      independent_bits_engine(const _RandomNumberEngine& __rng)
+      : _M_b(__rng) { }
+
+      /**
+       * @brief Move constructs a %independent_bits_engine engine.
+       *
+       * Copies an existing base class random number generator.
+       * @param __rng An existing (base class) engine object.
+       */
+      explicit
+      independent_bits_engine(_RandomNumberEngine&& __rng)
+      : _M_b(std::move(__rng)) { }
+
+      /**
+       * @brief Seed constructs a %independent_bits_engine engine.
+       *
+       * Constructs the underlying generator engine seeded with @p __s.
+       * @param __s A seed value for the base class engine.
+       */
+      explicit
+      independent_bits_engine(result_type __s)
+      : _M_b(__s) { }
+
+      /**
+       * @brief Generator construct a %independent_bits_engine engine.
+       *
+       * @param __q A seed sequence.
+       */
+      template<typename _Sseq, typename = _If_seed_seq<_Sseq>>
+        explicit
+        independent_bits_engine(_Sseq& __q)
+        : _M_b(__q)
+        { }
+
+      /**
+       * @brief Reseeds the %independent_bits_engine object with the default
+       *        seed for the underlying base class generator engine.
+       */
+      void
+      seed()
+      { _M_b.seed(); }
+
+      /**
+       * @brief Reseeds the %independent_bits_engine object with the default
+       *        seed for the underlying base class generator engine.
+       */
+      void
+      seed(result_type __s)
+      { _M_b.seed(__s); }
+
+      /**
+       * @brief Reseeds the %independent_bits_engine object with the given
+       *        seed sequence.
+       * @param __q A seed generator function.
+       */
+      template<typename _Sseq>
+        _If_seed_seq<_Sseq>
+        seed(_Sseq& __q)
+        { _M_b.seed(__q); }
+
+      /**
+       * @brief Gets a const reference to the underlying generator engine
+       *        object.
+       */
+      const _RandomNumberEngine&
+      base() const noexcept
+      { return _M_b; }
+
+      /**
+       * @brief Gets the minimum value in the generated random number range.
+       */
+      static constexpr result_type
+      min()
+      { return 0U; }
+
+      /**
+       * @brief Gets the maximum value in the generated random number range.
+       */
+      static constexpr result_type
+      max()
+      { return __detail::_Shift<_UIntType, __w>::__value - 1; }
+
+      /**
+       * @brief Discard a sequence of random numbers.
+       */
+      void
+      discard(unsigned long long __z)
+      {
+	for (; __z != 0ULL; --__z)
+	  (*this)();
+      }
+
+      /**
+       * @brief Gets the next value in the generated random number sequence.
+       */
+      result_type
+      operator()();
+
+      /**
+       * @brief Compares two %independent_bits_engine random number generator
+       * objects of the same type for equality.
+       *
+       * @param __lhs A %independent_bits_engine random number generator
+       *              object.
+       * @param __rhs Another %independent_bits_engine random number generator
+       *              object.
+       *
+       * @returns true if the infinite sequences of generated values
+       *          would be equal, false otherwise.
+       */
+      friend bool
+      operator==(const independent_bits_engine& __lhs,
+		 const independent_bits_engine& __rhs)
+      { return __lhs._M_b == __rhs._M_b; }
+
+      /**
+       * @brief Extracts the current state of a % subtract_with_carry_engine
+       *        random number generator engine @p __x from the input stream
+       *        @p __is.
+       *
+       * @param __is An input stream.
+       * @param __x  A %independent_bits_engine random number generator
+       *             engine.
+       *
+       * @returns The input stream with the state of @p __x extracted or in
+       *          an error state.
+       */
+      template<typename _CharT, typename _Traits>
+	friend std::basic_istream<_CharT, _Traits>&
+	operator>>(std::basic_istream<_CharT, _Traits>& __is,
+		   std::independent_bits_engine<_RandomNumberEngine,
+		   __w, _UIntType>& __x)
+	{
+	  __is >> __x._M_b;
+	  return __is;
+	}
+
+    private:
+      _RandomNumberEngine _M_b;
+    };
+
+  /**
+   * @brief Compares two %independent_bits_engine random number generator
+   * objects of the same type for inequality.
+   *
+   * @param __lhs A %independent_bits_engine random number generator
+   *              object.
+   * @param __rhs Another %independent_bits_engine random number generator
+   *              object.
+   *
+   * @returns true if the infinite sequences of generated values
+   *          would be different, false otherwise.
+   */
+  template<typename _RandomNumberEngine, size_t __w, typename _UIntType>
+    inline bool
+    operator!=(const std::independent_bits_engine<_RandomNumberEngine, __w,
+	       _UIntType>& __lhs,
+	       const std::independent_bits_engine<_RandomNumberEngine, __w,
+	       _UIntType>& __rhs)
+    { return !(__lhs == __rhs); }
+
+  /**
+   * @brief Inserts the current state of a %independent_bits_engine random
+   *        number generator engine @p __x into the output stream @p __os.
+   *
+   * @param __os An output stream.
+   * @param __x  A %independent_bits_engine random number generator engine.
+   *
+   * @returns The output stream with the state of @p __x inserted or in
+   *          an error state.
+   */
+  template<typename _RandomNumberEngine, size_t __w, typename _UIntType,
+	   typename _CharT, typename _Traits>
+    std::basic_ostream<_CharT, _Traits>&
+    operator<<(std::basic_ostream<_CharT, _Traits>& __os,
+	       const std::independent_bits_engine<_RandomNumberEngine,
+	       __w, _UIntType>& __x)
+    {
+      __os << __x.base();
+      return __os;
+    }
+
+
+  /**
+   * @brief Produces random numbers by reordering random numbers from some
+   * base engine.
+   *
+   * The values from the base engine are stored in a sequence of size @p __k
+   * and shuffled by an algorithm that depends on those values.
+   */
+  template<typename _RandomNumberEngine, size_t __k>
+    class shuffle_order_engine
+    {
+      static_assert(1u <= __k, "template argument substituting "
+		    "__k out of bound");
+
+    public:
+      /** The type of the generated random value. */
+      typedef typename _RandomNumberEngine::result_type result_type;
+
+      template<typename _Sseq>
+	using _If_seed_seq = typename enable_if<__detail::__is_seed_seq<
+	  _Sseq, shuffle_order_engine, result_type>::value>::type;
+
+      static constexpr size_t table_size = __k;
+
+      /**
+       * @brief Constructs a default %shuffle_order_engine engine.
+       *
+       * The underlying engine is default constructed as well.
+       */
+      shuffle_order_engine()
+      : _M_b()
+      { _M_initialize(); }
+
+      /**
+       * @brief Copy constructs a %shuffle_order_engine engine.
+       *
+       * Copies an existing base class random number generator.
+       * @param __rng An existing (base class) engine object.
+       */
+      explicit
+      shuffle_order_engine(const _RandomNumberEngine& __rng)
+      : _M_b(__rng)
+      { _M_initialize(); }
+
+      /**
+       * @brief Move constructs a %shuffle_order_engine engine.
+       *
+       * Copies an existing base class random number generator.
+       * @param __rng An existing (base class) engine object.
+       */
+      explicit
+      shuffle_order_engine(_RandomNumberEngine&& __rng)
+      : _M_b(std::move(__rng))
+      { _M_initialize(); }
+
+      /**
+       * @brief Seed constructs a %shuffle_order_engine engine.
+       *
+       * Constructs the underlying generator engine seeded with @p __s.
+       * @param __s A seed value for the base class engine.
+       */
+      explicit
+      shuffle_order_engine(result_type __s)
+      : _M_b(__s)
+      { _M_initialize(); }
+
+      /**
+       * @brief Generator construct a %shuffle_order_engine engine.
+       *
+       * @param __q A seed sequence.
+       */
+      template<typename _Sseq, typename = _If_seed_seq<_Sseq>>
+        explicit
+        shuffle_order_engine(_Sseq& __q)
+        : _M_b(__q)
+        { _M_initialize(); }
+
+      /**
+       * @brief Reseeds the %shuffle_order_engine object with the default seed
+                for the underlying base class generator engine.
+       */
+      void
+      seed()
+      {
+	_M_b.seed();
+	_M_initialize();
+      }
+
+      /**
+       * @brief Reseeds the %shuffle_order_engine object with the default seed
+       *        for the underlying base class generator engine.
+       */
+      void
+      seed(result_type __s)
+      {
+	_M_b.seed(__s);
+	_M_initialize();
+      }
+
+      /**
+       * @brief Reseeds the %shuffle_order_engine object with the given seed
+       *        sequence.
+       * @param __q A seed generator function.
+       */
+      template<typename _Sseq>
+        _If_seed_seq<_Sseq>
+        seed(_Sseq& __q)
+        {
+	  _M_b.seed(__q);
+	  _M_initialize();
+	}
+
+      /**
+       * Gets a const reference to the underlying generator engine object.
+       */
+      const _RandomNumberEngine&
+      base() const noexcept
+      { return _M_b; }
+
+      /**
+       * Gets the minimum value in the generated random number range.
+       */
+      static constexpr result_type
+      min()
+      { return _RandomNumberEngine::min(); }
+
+      /**
+       * Gets the maximum value in the generated random number range.
+       */
+      static constexpr result_type
+      max()
+      { return _RandomNumberEngine::max(); }
+
+      /**
+       * Discard a sequence of random numbers.
+       */
+      void
+      discard(unsigned long long __z)
+      {
+	for (; __z != 0ULL; --__z)
+	  (*this)();
+      }
+
+      /**
+       * Gets the next value in the generated random number sequence.
+       */
+      result_type
+      operator()();
+
+      /**
+       * Compares two %shuffle_order_engine random number generator objects
+       * of the same type for equality.
+       *
+       * @param __lhs A %shuffle_order_engine random number generator object.
+       * @param __rhs Another %shuffle_order_engine random number generator
+       *              object.
+       *
+       * @returns true if the infinite sequences of generated values
+       *          would be equal, false otherwise.
+      */
+      friend bool
+      operator==(const shuffle_order_engine& __lhs,
+		 const shuffle_order_engine& __rhs)
+      { return (__lhs._M_b == __rhs._M_b
+		&& std::equal(__lhs._M_v, __lhs._M_v + __k, __rhs._M_v)
+		&& __lhs._M_y == __rhs._M_y); }
+
+      /**
+       * @brief Inserts the current state of a %shuffle_order_engine random
+       *        number generator engine @p __x into the output stream
+	@p __os.
+       *
+       * @param __os An output stream.
+       * @param __x  A %shuffle_order_engine random number generator engine.
+       *
+       * @returns The output stream with the state of @p __x inserted or in
+       * an error state.
+       */
+      template<typename _RandomNumberEngine1, size_t __k1,
+	       typename _CharT, typename _Traits>
+	friend std::basic_ostream<_CharT, _Traits>&
+	operator<<(std::basic_ostream<_CharT, _Traits>& __os,
+		   const std::shuffle_order_engine<_RandomNumberEngine1,
+		   __k1>& __x);
+
+      /**
+       * @brief Extracts the current state of a % subtract_with_carry_engine
+       *        random number generator engine @p __x from the input stream
+       *        @p __is.
+       *
+       * @param __is An input stream.
+       * @param __x  A %shuffle_order_engine random number generator engine.
+       *
+       * @returns The input stream with the state of @p __x extracted or in
+       * an error state.
+       */
+      template<typename _RandomNumberEngine1, size_t __k1,
+	       typename _CharT, typename _Traits>
+	friend std::basic_istream<_CharT, _Traits>&
+	operator>>(std::basic_istream<_CharT, _Traits>& __is,
+		   std::shuffle_order_engine<_RandomNumberEngine1, __k1>& __x);
+
+    private:
+      void _M_initialize()
+      {
+	for (size_t __i = 0; __i < __k; ++__i)
+	  _M_v[__i] = _M_b();
+	_M_y = _M_b();
+      }
+
+      _RandomNumberEngine _M_b;
+      result_type _M_v[__k];
+      result_type _M_y;
+    };
+
+  /**
+   * Compares two %shuffle_order_engine random number generator objects
+   * of the same type for inequality.
+   *
+   * @param __lhs A %shuffle_order_engine random number generator object.
+   * @param __rhs Another %shuffle_order_engine random number generator
+   *              object.
+   *
+   * @returns true if the infinite sequences of generated values
+   *          would be different, false otherwise.
+   */
+  template<typename _RandomNumberEngine, size_t __k>
+    inline bool
+    operator!=(const std::shuffle_order_engine<_RandomNumberEngine,
+	       __k>& __lhs,
+	       const std::shuffle_order_engine<_RandomNumberEngine,
+	       __k>& __rhs)
+    { return !(__lhs == __rhs); }
+
+
+  /**
+   * The classic Minimum Standard rand0 of Lewis, Goodman, and Miller.
+   */
+  typedef linear_congruential_engine<uint_fast32_t, 16807UL, 0UL, 2147483647UL>
+  minstd_rand0;
+
+  /**
+   * An alternative LCR (Lehmer Generator function).
+   */
+  typedef linear_congruential_engine<uint_fast32_t, 48271UL, 0UL, 2147483647UL>
+  minstd_rand;
+
+  /**
+   * The classic Mersenne Twister.
+   *
+   * Reference:
+   * M. Matsumoto and T. Nishimura, Mersenne Twister: A 623-Dimensionally
+   * Equidistributed Uniform Pseudo-Random Number Generator, ACM Transactions
+   * on Modeling and Computer Simulation, Vol. 8, No. 1, January 1998, pp 3-30.
+   */
+  typedef mersenne_twister_engine<
+    uint_fast32_t,
+    32, 624, 397, 31,
+    0x9908b0dfUL, 11,
+    0xffffffffUL, 7,
+    0x9d2c5680UL, 15,
+    0xefc60000UL, 18, 1812433253UL> mt19937;
+
+  /**
+   * An alternative Mersenne Twister.
+   */
+  typedef mersenne_twister_engine<
+    uint_fast64_t,
+    64, 312, 156, 31,
+    0xb5026f5aa96619e9ULL, 29,
+    0x5555555555555555ULL, 17,
+    0x71d67fffeda60000ULL, 37,
+    0xfff7eee000000000ULL, 43,
+    6364136223846793005ULL> mt19937_64;
+
+  typedef subtract_with_carry_engine<uint_fast32_t, 24, 10, 24>
+    ranlux24_base;
+
+  typedef subtract_with_carry_engine<uint_fast64_t, 48, 5, 12>
+    ranlux48_base;
+
+  typedef discard_block_engine<ranlux24_base, 223, 23> ranlux24;
+
+  typedef discard_block_engine<ranlux48_base, 389, 11> ranlux48;
+
+  typedef shuffle_order_engine<minstd_rand0, 256> knuth_b;
+
+  typedef minstd_rand0 default_random_engine;
+
+  /**
+   * A standard interface to a platform-specific non-deterministic
+   * random number generator (if any are available).
+   */
+  class random_device
+  {
+  public:
+    /** The type of the generated random value. */
+    typedef unsigned int result_type;
+
+    // constructors, destructors and member functions
+
+    random_device() { _M_init("default"); }
+
+    explicit
+    random_device(const std::string& __token) { _M_init(__token); }
+
+#if defined _GLIBCXX_USE_DEV_RANDOM
+    ~random_device()
+    { _M_fini(); }
+#endif
+
+    static constexpr result_type
+    min()
+    { return std::numeric_limits<result_type>::min(); }
+
+    static constexpr result_type
+    max()
+    { return std::numeric_limits<result_type>::max(); }
+
+    double
+    entropy() const noexcept
+    {
+#ifdef _GLIBCXX_USE_DEV_RANDOM
+      return this->_M_getentropy();
+#else
+      return 0.0;
+#endif
+    }
+
+    result_type
+    operator()()
+    { return this->_M_getval(); }
+
+    // No copy functions.
+    random_device(const random_device&) = delete;
+    void operator=(const random_device&) = delete;
+
+  private:
+
+    void _M_init(const std::string& __token);
+    void _M_init_pretr1(const std::string& __token);
+    void _M_fini();
+
+    result_type _M_getval();
+    result_type _M_getval_pretr1();
+    double _M_getentropy() const noexcept;
+
+    void _M_init(const char*, size_t); // not exported from the shared library
+
+    __extension__ union
+    {
+      struct
+      {
+	void*      _M_file;
+	result_type (*_M_func)(void*);
+	int _M_fd;
+      };
+      mt19937    _M_mt;
+    };
+  };
+
+  /// @} group random_generators
+
+  /**
+   * @addtogroup random_distributions Random Number Distributions
+   * @ingroup random
+   * @{
+   */
+
+  /**
+   * @addtogroup random_distributions_uniform Uniform Distributions
+   * @ingroup random_distributions
+   * @{
+   */
+
+  // std::uniform_int_distribution is defined in <bits/uniform_int_dist.h>
+
+  /**
+   * @brief Return true if two uniform integer distributions have
+   *        different parameters.
+   */
+  template<typename _IntType>
+    inline bool
+    operator!=(const std::uniform_int_distribution<_IntType>& __d1,
+	       const std::uniform_int_distribution<_IntType>& __d2)
+    { return !(__d1 == __d2); }
+
+  /**
+   * @brief Inserts a %uniform_int_distribution random number
+   *        distribution @p __x into the output stream @p os.
+   *
+   * @param __os An output stream.
+   * @param __x  A %uniform_int_distribution random number distribution.
+   *
+   * @returns The output stream with the state of @p __x inserted or in
+   * an error state.
+   */
+  template<typename _IntType, typename _CharT, typename _Traits>
+    std::basic_ostream<_CharT, _Traits>&
+    operator<<(std::basic_ostream<_CharT, _Traits>&,
+	       const std::uniform_int_distribution<_IntType>&);
+
+  /**
+   * @brief Extracts a %uniform_int_distribution random number distribution
+   * @p __x from the input stream @p __is.
+   *
+   * @param __is An input stream.
+   * @param __x  A %uniform_int_distribution random number generator engine.
+   *
+   * @returns The input stream with @p __x extracted or in an error state.
+   */
+  template<typename _IntType, typename _CharT, typename _Traits>
+    std::basic_istream<_CharT, _Traits>&
+    operator>>(std::basic_istream<_CharT, _Traits>&,
+	       std::uniform_int_distribution<_IntType>&);
+
+
+  /**
+   * @brief Uniform continuous distribution for random numbers.
+   *
+   * A continuous random distribution on the range [min, max) with equal
+   * probability throughout the range.  The URNG should be real-valued and
+   * deliver number in the range [0, 1).
+   */
+  template<typename _RealType = double>
+    class uniform_real_distribution
+    {
+      static_assert(std::is_floating_point<_RealType>::value,
+		    "result_type must be a floating point type");
+
+    public:
+      /** The type of the range of the distribution. */
+      typedef _RealType result_type;
+
+      /** Parameter type. */
+      struct param_type
+      {
+	typedef uniform_real_distribution<_RealType> distribution_type;
+
+	param_type() : param_type(0) { }
+
+	explicit
+	param_type(_RealType __a, _RealType __b = _RealType(1))
+	: _M_a(__a), _M_b(__b)
+	{
+	  __glibcxx_assert(_M_a <= _M_b);
+	}
+
+	result_type
+	a() const
+	{ return _M_a; }
+
+	result_type
+	b() const
+	{ return _M_b; }
+
+	friend bool
+	operator==(const param_type& __p1, const param_type& __p2)
+	{ return __p1._M_a == __p2._M_a && __p1._M_b == __p2._M_b; }
+
+	friend bool
+	operator!=(const param_type& __p1, const param_type& __p2)
+	{ return !(__p1 == __p2); }
+
+      private:
+	_RealType _M_a;
+	_RealType _M_b;
+      };
+
+    public:
+      /**
+       * @brief Constructs a uniform_real_distribution object.
+       *
+       * The lower bound is set to 0.0 and the upper bound to 1.0
+       */
+      uniform_real_distribution() : uniform_real_distribution(0.0) { }
+
+      /**
+       * @brief Constructs a uniform_real_distribution object.
+       *
+       * @param __a [IN]  The lower bound of the distribution.
+       * @param __b [IN]  The upper bound of the distribution.
+       */
+      explicit
+      uniform_real_distribution(_RealType __a, _RealType __b = _RealType(1))
+      : _M_param(__a, __b)
+      { }
+
+      explicit
+      uniform_real_distribution(const param_type& __p)
+      : _M_param(__p)
+      { }
+
+      /**
+       * @brief Resets the distribution state.
+       *
+       * Does nothing for the uniform real distribution.
+       */
+      void
+      reset() { }
+
+      result_type
+      a() const
+      { return _M_param.a(); }
+
+      result_type
+      b() const
+      { return _M_param.b(); }
+
+      /**
+       * @brief Returns the parameter set of the distribution.
+       */
+      param_type
+      param() const
+      { return _M_param; }
+
+      /**
+       * @brief Sets the parameter set of the distribution.
+       * @param __param The new parameter set of the distribution.
+       */
+      void
+      param(const param_type& __param)
+      { _M_param = __param; }
+
+      /**
+       * @brief Returns the inclusive lower bound of the distribution range.
+       */
+      result_type
+      min() const
+      { return this->a(); }
+
+      /**
+       * @brief Returns the inclusive upper bound of the distribution range.
+       */
+      result_type
+      max() const
+      { return this->b(); }
+
+      /**
+       * @brief Generating functions.
+       */
+      template<typename _UniformRandomNumberGenerator>
+	result_type
+	operator()(_UniformRandomNumberGenerator& __urng)
+        { return this->operator()(__urng, _M_param); }
+
+      template<typename _UniformRandomNumberGenerator>
+	result_type
+	operator()(_UniformRandomNumberGenerator& __urng,
+		   const param_type& __p)
+	{
+	  __detail::_Adaptor<_UniformRandomNumberGenerator, result_type>
+	    __aurng(__urng);
+	  return (__aurng() * (__p.b() - __p.a())) + __p.a();
+	}
+
+      template<typename _ForwardIterator,
+	       typename _UniformRandomNumberGenerator>
+	void
+	__generate(_ForwardIterator __f, _ForwardIterator __t,
+		   _UniformRandomNumberGenerator& __urng)
+	{ this->__generate(__f, __t, __urng, _M_param); }
+
+      template<typename _ForwardIterator,
+	       typename _UniformRandomNumberGenerator>
+	void
+	__generate(_ForwardIterator __f, _ForwardIterator __t,
+		   _UniformRandomNumberGenerator& __urng,
+		   const param_type& __p)
+	{ this->__generate_impl(__f, __t, __urng, __p); }
+
+      template<typename _UniformRandomNumberGenerator>
+	void
+	__generate(result_type* __f, result_type* __t,
+		   _UniformRandomNumberGenerator& __urng,
+		   const param_type& __p)
+	{ this->__generate_impl(__f, __t, __urng, __p); }
+
+      /**
+       * @brief Return true if two uniform real distributions have
+       *        the same parameters.
+       */
+      friend bool
+      operator==(const uniform_real_distribution& __d1,
+		 const uniform_real_distribution& __d2)
+      { return __d1._M_param == __d2._M_param; }
+
+    private:
+      template<typename _ForwardIterator,
+	       typename _UniformRandomNumberGenerator>
+	void
+	__generate_impl(_ForwardIterator __f, _ForwardIterator __t,
+			_UniformRandomNumberGenerator& __urng,
+			const param_type& __p);
+
+      param_type _M_param;
+    };
+
+  /**
+   * @brief Return true if two uniform real distributions have
+   *        different parameters.
+   */
+  template<typename _IntType>
+    inline bool
+    operator!=(const std::uniform_real_distribution<_IntType>& __d1,
+	       const std::uniform_real_distribution<_IntType>& __d2)
+    { return !(__d1 == __d2); }
+
+  /**
+   * @brief Inserts a %uniform_real_distribution random number
+   *        distribution @p __x into the output stream @p __os.
+   *
+   * @param __os An output stream.
+   * @param __x  A %uniform_real_distribution random number distribution.
+   *
+   * @returns The output stream with the state of @p __x inserted or in
+   *          an error state.
+   */
+  template<typename _RealType, typename _CharT, typename _Traits>
+    std::basic_ostream<_CharT, _Traits>&
+    operator<<(std::basic_ostream<_CharT, _Traits>&,
+	       const std::uniform_real_distribution<_RealType>&);
+
+  /**
+   * @brief Extracts a %uniform_real_distribution random number distribution
+   * @p __x from the input stream @p __is.
+   *
+   * @param __is An input stream.
+   * @param __x  A %uniform_real_distribution random number generator engine.
+   *
+   * @returns The input stream with @p __x extracted or in an error state.
+   */
+  template<typename _RealType, typename _CharT, typename _Traits>
+    std::basic_istream<_CharT, _Traits>&
+    operator>>(std::basic_istream<_CharT, _Traits>&,
+	       std::uniform_real_distribution<_RealType>&);
+
+  /// @} group random_distributions_uniform
+
+  /**
+   * @addtogroup random_distributions_normal Normal Distributions
+   * @ingroup random_distributions
+   * @{
+   */
+
+  /**
+   * @brief A normal continuous distribution for random numbers.
+   *
+   * The formula for the normal probability density function is
+   * @f[
+   *     p(x|\mu,\sigma) = \frac{1}{\sigma \sqrt{2 \pi}}
+   *            e^{- \frac{{x - \mu}^ {2}}{2 \sigma ^ {2}} } 
+   * @f]
+   */
+  template<typename _RealType = double>
+    class normal_distribution
+    {
+      static_assert(std::is_floating_point<_RealType>::value,
+		    "result_type must be a floating point type");
+
+    public:
+      /** The type of the range of the distribution. */
+      typedef _RealType result_type;
+
+      /** Parameter type. */
+      struct param_type
+      {
+	typedef normal_distribution<_RealType> distribution_type;
+
+	param_type() : param_type(0.0) { }
+
+	explicit
+	param_type(_RealType __mean, _RealType __stddev = _RealType(1))
+	: _M_mean(__mean), _M_stddev(__stddev)
+	{
+	  __glibcxx_assert(_M_stddev > _RealType(0));
+	}
+
+	_RealType
+	mean() const
+	{ return _M_mean; }
+
+	_RealType
+	stddev() const
+	{ return _M_stddev; }
+
+	friend bool
+	operator==(const param_type& __p1, const param_type& __p2)
+	{ return (__p1._M_mean == __p2._M_mean
+		  && __p1._M_stddev == __p2._M_stddev); }
+
+	friend bool
+	operator!=(const param_type& __p1, const param_type& __p2)
+	{ return !(__p1 == __p2); }
+
+      private:
+	_RealType _M_mean;
+	_RealType _M_stddev;
+      };
+
+    public:
+      normal_distribution() : normal_distribution(0.0) { }
+
+      /**
+       * Constructs a normal distribution with parameters @f$mean@f$ and
+       * standard deviation.
+       */
+      explicit
+      normal_distribution(result_type __mean,
+			  result_type __stddev = result_type(1))
+      : _M_param(__mean, __stddev)
+      { }
+
+      explicit
+      normal_distribution(const param_type& __p)
+      : _M_param(__p)
+      { }
+
+      /**
+       * @brief Resets the distribution state.
+       */
+      void
+      reset()
+      { _M_saved_available = false; }
+
+      /**
+       * @brief Returns the mean of the distribution.
+       */
+      _RealType
+      mean() const
+      { return _M_param.mean(); }
+
+      /**
+       * @brief Returns the standard deviation of the distribution.
+       */
+      _RealType
+      stddev() const
+      { return _M_param.stddev(); }
+
+      /**
+       * @brief Returns the parameter set of the distribution.
+       */
+      param_type
+      param() const
+      { return _M_param; }
+
+      /**
+       * @brief Sets the parameter set of the distribution.
+       * @param __param The new parameter set of the distribution.
+       */
+      void
+      param(const param_type& __param)
+      { _M_param = __param; }
+
+      /**
+       * @brief Returns the greatest lower bound value of the distribution.
+       */
+      result_type
+      min() const
+      { return std::numeric_limits<result_type>::lowest(); }
+
+      /**
+       * @brief Returns the least upper bound value of the distribution.
+       */
+      result_type
+      max() const
+      { return std::numeric_limits<result_type>::max(); }
+
+      /**
+       * @brief Generating functions.
+       */
+      template<typename _UniformRandomNumberGenerator>
+	result_type
+	operator()(_UniformRandomNumberGenerator& __urng)
+	{ return this->operator()(__urng, _M_param); }
+
+      template<typename _UniformRandomNumberGenerator>
+	result_type
+	operator()(_UniformRandomNumberGenerator& __urng,
+		   const param_type& __p);
+
+      template<typename _ForwardIterator,
+	       typename _UniformRandomNumberGenerator>
+	void
+	__generate(_ForwardIterator __f, _ForwardIterator __t,
+		   _UniformRandomNumberGenerator& __urng)
+	{ this->__generate(__f, __t, __urng, _M_param); }
+
+      template<typename _ForwardIterator,
+	       typename _UniformRandomNumberGenerator>
+	void
+	__generate(_ForwardIterator __f, _ForwardIterator __t,
+		   _UniformRandomNumberGenerator& __urng,
+		   const param_type& __p)
+	{ this->__generate_impl(__f, __t, __urng, __p); }
+
+      template<typename _UniformRandomNumberGenerator>
+	void
+	__generate(result_type* __f, result_type* __t,
+		   _UniformRandomNumberGenerator& __urng,
+		   const param_type& __p)
+	{ this->__generate_impl(__f, __t, __urng, __p); }
+
+      /**
+       * @brief Return true if two normal distributions have
+       *        the same parameters and the sequences that would
+       *        be generated are equal.
+       */
+      template<typename _RealType1>
+	friend bool
+        operator==(const std::normal_distribution<_RealType1>& __d1,
+		   const std::normal_distribution<_RealType1>& __d2);
+
+      /**
+       * @brief Inserts a %normal_distribution random number distribution
+       * @p __x into the output stream @p __os.
+       *
+       * @param __os An output stream.
+       * @param __x  A %normal_distribution random number distribution.
+       *
+       * @returns The output stream with the state of @p __x inserted or in
+       * an error state.
+       */
+      template<typename _RealType1, typename _CharT, typename _Traits>
+	friend std::basic_ostream<_CharT, _Traits>&
+	operator<<(std::basic_ostream<_CharT, _Traits>& __os,
+		   const std::normal_distribution<_RealType1>& __x);
+
+      /**
+       * @brief Extracts a %normal_distribution random number distribution
+       * @p __x from the input stream @p __is.
+       *
+       * @param __is An input stream.
+       * @param __x  A %normal_distribution random number generator engine.
+       *
+       * @returns The input stream with @p __x extracted or in an error
+       *          state.
+       */
+      template<typename _RealType1, typename _CharT, typename _Traits>
+	friend std::basic_istream<_CharT, _Traits>&
+	operator>>(std::basic_istream<_CharT, _Traits>& __is,
+		   std::normal_distribution<_RealType1>& __x);
+
+    private:
+      template<typename _ForwardIterator,
+	       typename _UniformRandomNumberGenerator>
+	void
+	__generate_impl(_ForwardIterator __f, _ForwardIterator __t,
+			_UniformRandomNumberGenerator& __urng,
+			const param_type& __p);
+
+      param_type  _M_param;
+      result_type _M_saved = 0;
+      bool        _M_saved_available = false;
+    };
+
+  /**
+   * @brief Return true if two normal distributions are different.
+   */
+  template<typename _RealType>
+    inline bool
+    operator!=(const std::normal_distribution<_RealType>& __d1,
+	       const std::normal_distribution<_RealType>& __d2)
+    { return !(__d1 == __d2); }
+
+
+  /**
+   * @brief A lognormal_distribution random number distribution.
+   *
+   * The formula for the normal probability mass function is
+   * @f[
+   *     p(x|m,s) = \frac{1}{sx\sqrt{2\pi}}
+   *                \exp{-\frac{(\ln{x} - m)^2}{2s^2}} 
+   * @f]
+   */
+  template<typename _RealType = double>
+    class lognormal_distribution
+    {
+      static_assert(std::is_floating_point<_RealType>::value,
+		    "result_type must be a floating point type");
+
+    public:
+      /** The type of the range of the distribution. */
+      typedef _RealType result_type;
+
+      /** Parameter type. */
+      struct param_type
+      {
+	typedef lognormal_distribution<_RealType> distribution_type;
+
+	param_type() : param_type(0.0) { }
+
+	explicit
+	param_type(_RealType __m, _RealType __s = _RealType(1))
+	: _M_m(__m), _M_s(__s)
+	{ }
+
+	_RealType
+	m() const
+	{ return _M_m; }
+
+	_RealType
+	s() const
+	{ return _M_s; }
+
+	friend bool
+	operator==(const param_type& __p1, const param_type& __p2)
+	{ return __p1._M_m == __p2._M_m && __p1._M_s == __p2._M_s; }
+
+	friend bool
+	operator!=(const param_type& __p1, const param_type& __p2)
+	{ return !(__p1 == __p2); }
+
+      private:
+	_RealType _M_m;
+	_RealType _M_s;
+      };
+
+      lognormal_distribution() : lognormal_distribution(0.0) { }
+
+      explicit
+      lognormal_distribution(_RealType __m, _RealType __s = _RealType(1))
+      : _M_param(__m, __s), _M_nd()
+      { }
+
+      explicit
+      lognormal_distribution(const param_type& __p)
+      : _M_param(__p), _M_nd()
+      { }
+
+      /**
+       * Resets the distribution state.
+       */
+      void
+      reset()
+      { _M_nd.reset(); }
+
+      /**
+       *
+       */
+      _RealType
+      m() const
+      { return _M_param.m(); }
+
+      _RealType
+      s() const
+      { return _M_param.s(); }
+
+      /**
+       * @brief Returns the parameter set of the distribution.
+       */
+      param_type
+      param() const
+      { return _M_param; }
+
+      /**
+       * @brief Sets the parameter set of the distribution.
+       * @param __param The new parameter set of the distribution.
+       */
+      void
+      param(const param_type& __param)
+      { _M_param = __param; }
+
+      /**
+       * @brief Returns the greatest lower bound value of the distribution.
+       */
+      result_type
+      min() const
+      { return result_type(0); }
+
+      /**
+       * @brief Returns the least upper bound value of the distribution.
+       */
+      result_type
+      max() const
+      { return std::numeric_limits<result_type>::max(); }
+
+      /**
+       * @brief Generating functions.
+       */
+      template<typename _UniformRandomNumberGenerator>
+	result_type
+	operator()(_UniformRandomNumberGenerator& __urng)
+        { return this->operator()(__urng, _M_param); }
+
+      template<typename _UniformRandomNumberGenerator>
+	result_type
+	operator()(_UniformRandomNumberGenerator& __urng,
+		   const param_type& __p)
+        { return std::exp(__p.s() * _M_nd(__urng) + __p.m()); }
+
+      template<typename _ForwardIterator,
+	       typename _UniformRandomNumberGenerator>
+	void
+	__generate(_ForwardIterator __f, _ForwardIterator __t,
+		   _UniformRandomNumberGenerator& __urng)
+	{ this->__generate(__f, __t, __urng, _M_param); }
+
+      template<typename _ForwardIterator,
+	       typename _UniformRandomNumberGenerator>
+	void
+	__generate(_ForwardIterator __f, _ForwardIterator __t,
+		   _UniformRandomNumberGenerator& __urng,
+		   const param_type& __p)
+	{ this->__generate_impl(__f, __t, __urng, __p); }
+
+      template<typename _UniformRandomNumberGenerator>
+	void
+	__generate(result_type* __f, result_type* __t,
+		   _UniformRandomNumberGenerator& __urng,
+		   const param_type& __p)
+	{ this->__generate_impl(__f, __t, __urng, __p); }
+
+      /**
+       * @brief Return true if two lognormal distributions have
+       *        the same parameters and the sequences that would
+       *        be generated are equal.
+       */
+      friend bool
+      operator==(const lognormal_distribution& __d1,
+		 const lognormal_distribution& __d2)
+      { return (__d1._M_param == __d2._M_param
+		&& __d1._M_nd == __d2._M_nd); }
+
+      /**
+       * @brief Inserts a %lognormal_distribution random number distribution
+       * @p __x into the output stream @p __os.
+       *
+       * @param __os An output stream.
+       * @param __x  A %lognormal_distribution random number distribution.
+       *
+       * @returns The output stream with the state of @p __x inserted or in
+       * an error state.
+       */
+      template<typename _RealType1, typename _CharT, typename _Traits>
+	friend std::basic_ostream<_CharT, _Traits>&
+	operator<<(std::basic_ostream<_CharT, _Traits>& __os,
+		   const std::lognormal_distribution<_RealType1>& __x);
+
+      /**
+       * @brief Extracts a %lognormal_distribution random number distribution
+       * @p __x from the input stream @p __is.
+       *
+       * @param __is An input stream.
+       * @param __x A %lognormal_distribution random number
+       *            generator engine.
+       *
+       * @returns The input stream with @p __x extracted or in an error state.
+       */
+      template<typename _RealType1, typename _CharT, typename _Traits>
+	friend std::basic_istream<_CharT, _Traits>&
+	operator>>(std::basic_istream<_CharT, _Traits>& __is,
+		   std::lognormal_distribution<_RealType1>& __x);
+
+    private:
+      template<typename _ForwardIterator,
+	       typename _UniformRandomNumberGenerator>
+	void
+	__generate_impl(_ForwardIterator __f, _ForwardIterator __t,
+			_UniformRandomNumberGenerator& __urng,
+			const param_type& __p);
+
+      param_type _M_param;
+
+      std::normal_distribution<result_type> _M_nd;
+    };
+
+  /**
+   * @brief Return true if two lognormal distributions are different.
+   */
+  template<typename _RealType>
+    inline bool
+    operator!=(const std::lognormal_distribution<_RealType>& __d1,
+	       const std::lognormal_distribution<_RealType>& __d2)
+    { return !(__d1 == __d2); }
+
+
+  /**
+   * @brief A gamma continuous distribution for random numbers.
+   *
+   * The formula for the gamma probability density function is:
+   * @f[
+   *     p(x|\alpha,\beta) = \frac{1}{\beta\Gamma(\alpha)}
+   *                         (x/\beta)^{\alpha - 1} e^{-x/\beta} 
+   * @f]
+   */
+  template<typename _RealType = double>
+    class gamma_distribution
+    {
+      static_assert(std::is_floating_point<_RealType>::value,
+		    "result_type must be a floating point type");
+
+    public:
+      /** The type of the range of the distribution. */
+      typedef _RealType result_type;
+
+      /** Parameter type. */
+      struct param_type
+      {
+	typedef gamma_distribution<_RealType> distribution_type;
+	friend class gamma_distribution<_RealType>;
+
+	param_type() : param_type(1.0) { }
+
+	explicit
+	param_type(_RealType __alpha_val, _RealType __beta_val = _RealType(1))
+	: _M_alpha(__alpha_val), _M_beta(__beta_val)
+	{
+	  __glibcxx_assert(_M_alpha > _RealType(0));
+	  _M_initialize();
+	}
+
+	_RealType
+	alpha() const
+	{ return _M_alpha; }
+
+	_RealType
+	beta() const
+	{ return _M_beta; }
+
+	friend bool
+	operator==(const param_type& __p1, const param_type& __p2)
+	{ return (__p1._M_alpha == __p2._M_alpha
+		  && __p1._M_beta == __p2._M_beta); }
+
+	friend bool
+	operator!=(const param_type& __p1, const param_type& __p2)
+	{ return !(__p1 == __p2); }
+
+      private:
+	void
+	_M_initialize();
+
+	_RealType _M_alpha;
+	_RealType _M_beta;
+
+	_RealType _M_malpha, _M_a2;
+      };
+
+    public:
+      /**
+       * @brief Constructs a gamma distribution with parameters 1 and 1.
+       */
+      gamma_distribution() : gamma_distribution(1.0) { }
+
+      /**
+       * @brief Constructs a gamma distribution with parameters
+       * @f$\alpha@f$ and @f$\beta@f$.
+       */
+      explicit
+      gamma_distribution(_RealType __alpha_val,
+			 _RealType __beta_val = _RealType(1))
+      : _M_param(__alpha_val, __beta_val), _M_nd()
+      { }
+
+      explicit
+      gamma_distribution(const param_type& __p)
+      : _M_param(__p), _M_nd()
+      { }
+
+      /**
+       * @brief Resets the distribution state.
+       */
+      void
+      reset()
+      { _M_nd.reset(); }
+
+      /**
+       * @brief Returns the @f$\alpha@f$ of the distribution.
+       */
+      _RealType
+      alpha() const
+      { return _M_param.alpha(); }
+
+      /**
+       * @brief Returns the @f$\beta@f$ of the distribution.
+       */
+      _RealType
+      beta() const
+      { return _M_param.beta(); }
+
+      /**
+       * @brief Returns the parameter set of the distribution.
+       */
+      param_type
+      param() const
+      { return _M_param; }
+
+      /**
+       * @brief Sets the parameter set of the distribution.
+       * @param __param The new parameter set of the distribution.
+       */
+      void
+      param(const param_type& __param)
+      { _M_param = __param; }
+
+      /**
+       * @brief Returns the greatest lower bound value of the distribution.
+       */
+      result_type
+      min() const
+      { return result_type(0); }
+
+      /**
+       * @brief Returns the least upper bound value of the distribution.
+       */
+      result_type
+      max() const
+      { return std::numeric_limits<result_type>::max(); }
+
+      /**
+       * @brief Generating functions.
+       */
+      template<typename _UniformRandomNumberGenerator>
+	result_type
+	operator()(_UniformRandomNumberGenerator& __urng)
+	{ return this->operator()(__urng, _M_param); }
+
+      template<typename _UniformRandomNumberGenerator>
+	result_type
+	operator()(_UniformRandomNumberGenerator& __urng,
+		   const param_type& __p);
+
+      template<typename _ForwardIterator,
+	       typename _UniformRandomNumberGenerator>
+	void
+	__generate(_ForwardIterator __f, _ForwardIterator __t,
+		   _UniformRandomNumberGenerator& __urng)
+	{ this->__generate(__f, __t, __urng, _M_param); }
+
+      template<typename _ForwardIterator,
+	       typename _UniformRandomNumberGenerator>
+	void
+	__generate(_ForwardIterator __f, _ForwardIterator __t,
+		   _UniformRandomNumberGenerator& __urng,
+		   const param_type& __p)
+	{ this->__generate_impl(__f, __t, __urng, __p); }
+
+      template<typename _UniformRandomNumberGenerator>
+	void
+	__generate(result_type* __f, result_type* __t,
+		   _UniformRandomNumberGenerator& __urng,
+		   const param_type& __p)
+	{ this->__generate_impl(__f, __t, __urng, __p); }
+
+      /**
+       * @brief Return true if two gamma distributions have the same
+       *        parameters and the sequences that would be generated
+       *        are equal.
+       */
+      friend bool
+      operator==(const gamma_distribution& __d1,
+		 const gamma_distribution& __d2)
+      { return (__d1._M_param == __d2._M_param
+		&& __d1._M_nd == __d2._M_nd); }
+
+      /**
+       * @brief Inserts a %gamma_distribution random number distribution
+       * @p __x into the output stream @p __os.
+       *
+       * @param __os An output stream.
+       * @param __x  A %gamma_distribution random number distribution.
+       *
+       * @returns The output stream with the state of @p __x inserted or in
+       * an error state.
+       */
+      template<typename _RealType1, typename _CharT, typename _Traits>
+	friend std::basic_ostream<_CharT, _Traits>&
+	operator<<(std::basic_ostream<_CharT, _Traits>& __os,
+		   const std::gamma_distribution<_RealType1>& __x);
+
+      /**
+       * @brief Extracts a %gamma_distribution random number distribution
+       * @p __x from the input stream @p __is.
+       *
+       * @param __is An input stream.
+       * @param __x  A %gamma_distribution random number generator engine.
+       *
+       * @returns The input stream with @p __x extracted or in an error state.
+       */
+      template<typename _RealType1, typename _CharT, typename _Traits>
+	friend std::basic_istream<_CharT, _Traits>&
+	operator>>(std::basic_istream<_CharT, _Traits>& __is,
+		   std::gamma_distribution<_RealType1>& __x);
+
+    private:
+      template<typename _ForwardIterator,
+	       typename _UniformRandomNumberGenerator>
+	void
+	__generate_impl(_ForwardIterator __f, _ForwardIterator __t,
+			_UniformRandomNumberGenerator& __urng,
+			const param_type& __p);
+
+      param_type _M_param;
+
+      std::normal_distribution<result_type> _M_nd;
+    };
+
+  /**
+   * @brief Return true if two gamma distributions are different.
+   */
+   template<typename _RealType>
+     inline bool
+     operator!=(const std::gamma_distribution<_RealType>& __d1,
+		const std::gamma_distribution<_RealType>& __d2)
+    { return !(__d1 == __d2); }
+
+
+  /**
+   * @brief A chi_squared_distribution random number distribution.
+   *
+   * The formula for the normal probability mass function is
+   * @f$p(x|n) = \frac{x^{(n/2) - 1}e^{-x/2}}{\Gamma(n/2) 2^{n/2}}@f$
+   */
+  template<typename _RealType = double>
+    class chi_squared_distribution
+    {
+      static_assert(std::is_floating_point<_RealType>::value,
+		    "result_type must be a floating point type");
+
+    public:
+      /** The type of the range of the distribution. */
+      typedef _RealType result_type;
+
+      /** Parameter type. */
+      struct param_type
+      {
+	typedef chi_squared_distribution<_RealType> distribution_type;
+
+	param_type() : param_type(1) { }
+
+	explicit
+	param_type(_RealType __n)
+	: _M_n(__n)
+	{ }
+
+	_RealType
+	n() const
+	{ return _M_n; }
+
+	friend bool
+	operator==(const param_type& __p1, const param_type& __p2)
+	{ return __p1._M_n == __p2._M_n; }
+
+	friend bool
+	operator!=(const param_type& __p1, const param_type& __p2)
+	{ return !(__p1 == __p2); }
+
+      private:
+	_RealType _M_n;
+      };
+
+      chi_squared_distribution() : chi_squared_distribution(1) { }
+
+      explicit
+      chi_squared_distribution(_RealType __n)
+      : _M_param(__n), _M_gd(__n / 2)
+      { }
+
+      explicit
+      chi_squared_distribution(const param_type& __p)
+      : _M_param(__p), _M_gd(__p.n() / 2)
+      { }
+
+      /**
+       * @brief Resets the distribution state.
+       */
+      void
+      reset()
+      { _M_gd.reset(); }
+
+      /**
+       *
+       */
+      _RealType
+      n() const
+      { return _M_param.n(); }
+
+      /**
+       * @brief Returns the parameter set of the distribution.
+       */
+      param_type
+      param() const
+      { return _M_param; }
+
+      /**
+       * @brief Sets the parameter set of the distribution.
+       * @param __param The new parameter set of the distribution.
+       */
+      void
+      param(const param_type& __param)
+      {
+	_M_param = __param;
+	typedef typename std::gamma_distribution<result_type>::param_type
+	  param_type;
+	_M_gd.param(param_type{__param.n() / 2});
+      }
+
+      /**
+       * @brief Returns the greatest lower bound value of the distribution.
+       */
+      result_type
+      min() const
+      { return result_type(0); }
+
+      /**
+       * @brief Returns the least upper bound value of the distribution.
+       */
+      result_type
+      max() const
+      { return std::numeric_limits<result_type>::max(); }
+
+      /**
+       * @brief Generating functions.
+       */
+      template<typename _UniformRandomNumberGenerator>
+	result_type
+	operator()(_UniformRandomNumberGenerator& __urng)
+	{ return 2 * _M_gd(__urng); }
+
+      template<typename _UniformRandomNumberGenerator>
+	result_type
+	operator()(_UniformRandomNumberGenerator& __urng,
+		   const param_type& __p)
+        {
+	  typedef typename std::gamma_distribution<result_type>::param_type
+	    param_type;
+	  return 2 * _M_gd(__urng, param_type(__p.n() / 2));
+	}
+
+      template<typename _ForwardIterator,
+	       typename _UniformRandomNumberGenerator>
+	void
+	__generate(_ForwardIterator __f, _ForwardIterator __t,
+		   _UniformRandomNumberGenerator& __urng)
+        { this->__generate_impl(__f, __t, __urng); }
+
+      template<typename _ForwardIterator,
+	       typename _UniformRandomNumberGenerator>
+	void
+	__generate(_ForwardIterator __f, _ForwardIterator __t,
+		   _UniformRandomNumberGenerator& __urng,
+		   const param_type& __p)
+	{ typename std::gamma_distribution<result_type>::param_type
+	    __p2(__p.n() / 2);
+	  this->__generate_impl(__f, __t, __urng, __p2); }
+
+      template<typename _UniformRandomNumberGenerator>
+	void
+	__generate(result_type* __f, result_type* __t,
+		   _UniformRandomNumberGenerator& __urng)
+        { this->__generate_impl(__f, __t, __urng); }
+
+      template<typename _UniformRandomNumberGenerator>
+	void
+	__generate(result_type* __f, result_type* __t,
+		   _UniformRandomNumberGenerator& __urng,
+		   const param_type& __p)
+	{ typename std::gamma_distribution<result_type>::param_type
+	    __p2(__p.n() / 2);
+	  this->__generate_impl(__f, __t, __urng, __p2); }
+
+      /**
+       * @brief Return true if two Chi-squared distributions have
+       *        the same parameters and the sequences that would be
+       *        generated are equal.
+       */
+      friend bool
+      operator==(const chi_squared_distribution& __d1,
+		 const chi_squared_distribution& __d2)
+      { return __d1._M_param == __d2._M_param && __d1._M_gd == __d2._M_gd; }
+
+      /**
+       * @brief Inserts a %chi_squared_distribution random number distribution
+       * @p __x into the output stream @p __os.
+       *
+       * @param __os An output stream.
+       * @param __x  A %chi_squared_distribution random number distribution.
+       *
+       * @returns The output stream with the state of @p __x inserted or in
+       * an error state.
+       */
+      template<typename _RealType1, typename _CharT, typename _Traits>
+	friend std::basic_ostream<_CharT, _Traits>&
+	operator<<(std::basic_ostream<_CharT, _Traits>& __os,
+		   const std::chi_squared_distribution<_RealType1>& __x);
+
+      /**
+       * @brief Extracts a %chi_squared_distribution random number distribution
+       * @p __x from the input stream @p __is.
+       *
+       * @param __is An input stream.
+       * @param __x A %chi_squared_distribution random number
+       *            generator engine.
+       *
+       * @returns The input stream with @p __x extracted or in an error state.
+       */
+      template<typename _RealType1, typename _CharT, typename _Traits>
+	friend std::basic_istream<_CharT, _Traits>&
+	operator>>(std::basic_istream<_CharT, _Traits>& __is,
+		   std::chi_squared_distribution<_RealType1>& __x);
+
+    private:
+      template<typename _ForwardIterator,
+	       typename _UniformRandomNumberGenerator>
+	void
+	__generate_impl(_ForwardIterator __f, _ForwardIterator __t,
+			_UniformRandomNumberGenerator& __urng);
+
+      template<typename _ForwardIterator,
+	       typename _UniformRandomNumberGenerator>
+	void
+	__generate_impl(_ForwardIterator __f, _ForwardIterator __t,
+			_UniformRandomNumberGenerator& __urng,
+			const typename
+			std::gamma_distribution<result_type>::param_type& __p);
+
+      param_type _M_param;
+
+      std::gamma_distribution<result_type> _M_gd;
+    };
+
+  /**
+   * @brief Return true if two Chi-squared distributions are different.
+   */
+  template<typename _RealType>
+    inline bool
+    operator!=(const std::chi_squared_distribution<_RealType>& __d1,
+	       const std::chi_squared_distribution<_RealType>& __d2)
+    { return !(__d1 == __d2); }
+
+
+  /**
+   * @brief A cauchy_distribution random number distribution.
+   *
+   * The formula for the normal probability mass function is
+   * @f$p(x|a,b) = (\pi b (1 + (\frac{x-a}{b})^2))^{-1}@f$
+   */
+  template<typename _RealType = double>
+    class cauchy_distribution
+    {
+      static_assert(std::is_floating_point<_RealType>::value,
+		    "result_type must be a floating point type");
+
+    public:
+      /** The type of the range of the distribution. */
+      typedef _RealType result_type;
+
+      /** Parameter type. */
+      struct param_type
+      {
+	typedef cauchy_distribution<_RealType> distribution_type;
+
+	param_type() : param_type(0) { }
+
+	explicit
+	param_type(_RealType __a, _RealType __b = _RealType(1))
+	: _M_a(__a), _M_b(__b)
+	{ }
+
+	_RealType
+	a() const
+	{ return _M_a; }
+
+	_RealType
+	b() const
+	{ return _M_b; }
+
+	friend bool
+	operator==(const param_type& __p1, const param_type& __p2)
+	{ return __p1._M_a == __p2._M_a && __p1._M_b == __p2._M_b; }
+
+	friend bool
+	operator!=(const param_type& __p1, const param_type& __p2)
+	{ return !(__p1 == __p2); }
+
+      private:
+	_RealType _M_a;
+	_RealType _M_b;
+      };
+
+      cauchy_distribution() : cauchy_distribution(0.0) { }
+
+      explicit
+      cauchy_distribution(_RealType __a, _RealType __b = 1.0)
+      : _M_param(__a, __b)
+      { }
+
+      explicit
+      cauchy_distribution(const param_type& __p)
+      : _M_param(__p)
+      { }
+
+      /**
+       * @brief Resets the distribution state.
+       */
+      void
+      reset()
+      { }
+
+      /**
+       *
+       */
+      _RealType
+      a() const
+      { return _M_param.a(); }
+
+      _RealType
+      b() const
+      { return _M_param.b(); }
+
+      /**
+       * @brief Returns the parameter set of the distribution.
+       */
+      param_type
+      param() const
+      { return _M_param; }
+
+      /**
+       * @brief Sets the parameter set of the distribution.
+       * @param __param The new parameter set of the distribution.
+       */
+      void
+      param(const param_type& __param)
+      { _M_param = __param; }
+
+      /**
+       * @brief Returns the greatest lower bound value of the distribution.
+       */
+      result_type
+      min() const
+      { return std::numeric_limits<result_type>::lowest(); }
+
+      /**
+       * @brief Returns the least upper bound value of the distribution.
+       */
+      result_type
+      max() const
+      { return std::numeric_limits<result_type>::max(); }
+
+      /**
+       * @brief Generating functions.
+       */
+      template<typename _UniformRandomNumberGenerator>
+	result_type
+	operator()(_UniformRandomNumberGenerator& __urng)
+	{ return this->operator()(__urng, _M_param); }
+
+      template<typename _UniformRandomNumberGenerator>
+	result_type
+	operator()(_UniformRandomNumberGenerator& __urng,
+		   const param_type& __p);
+
+      template<typename _ForwardIterator,
+	       typename _UniformRandomNumberGenerator>
+	void
+	__generate(_ForwardIterator __f, _ForwardIterator __t,
+		   _UniformRandomNumberGenerator& __urng)
+	{ this->__generate(__f, __t, __urng, _M_param); }
+
+      template<typename _ForwardIterator,
+	       typename _UniformRandomNumberGenerator>
+	void
+	__generate(_ForwardIterator __f, _ForwardIterator __t,
+		   _UniformRandomNumberGenerator& __urng,
+		   const param_type& __p)
+	{ this->__generate_impl(__f, __t, __urng, __p); }
+
+      template<typename _UniformRandomNumberGenerator>
+	void
+	__generate(result_type* __f, result_type* __t,
+		   _UniformRandomNumberGenerator& __urng,
+		   const param_type& __p)
+	{ this->__generate_impl(__f, __t, __urng, __p); }
+
+      /**
+       * @brief Return true if two Cauchy distributions have
+       *        the same parameters.
+       */
+      friend bool
+      operator==(const cauchy_distribution& __d1,
+		 const cauchy_distribution& __d2)
+      { return __d1._M_param == __d2._M_param; }
+
+    private:
+      template<typename _ForwardIterator,
+	       typename _UniformRandomNumberGenerator>
+	void
+	__generate_impl(_ForwardIterator __f, _ForwardIterator __t,
+			_UniformRandomNumberGenerator& __urng,
+			const param_type& __p);
+
+      param_type _M_param;
+    };
+
+  /**
+   * @brief Return true if two Cauchy distributions have
+   *        different parameters.
+   */
+  template<typename _RealType>
+    inline bool
+    operator!=(const std::cauchy_distribution<_RealType>& __d1,
+	       const std::cauchy_distribution<_RealType>& __d2)
+    { return !(__d1 == __d2); }
+
+  /**
+   * @brief Inserts a %cauchy_distribution random number distribution
+   * @p __x into the output stream @p __os.
+   *
+   * @param __os An output stream.
+   * @param __x  A %cauchy_distribution random number distribution.
+   *
+   * @returns The output stream with the state of @p __x inserted or in
+   * an error state.
+   */
+  template<typename _RealType, typename _CharT, typename _Traits>
+    std::basic_ostream<_CharT, _Traits>&
+    operator<<(std::basic_ostream<_CharT, _Traits>& __os,
+	       const std::cauchy_distribution<_RealType>& __x);
+
+  /**
+   * @brief Extracts a %cauchy_distribution random number distribution
+   * @p __x from the input stream @p __is.
+   *
+   * @param __is An input stream.
+   * @param __x A %cauchy_distribution random number
+   *            generator engine.
+   *
+   * @returns The input stream with @p __x extracted or in an error state.
+   */
+  template<typename _RealType, typename _CharT, typename _Traits>
+    std::basic_istream<_CharT, _Traits>&
+    operator>>(std::basic_istream<_CharT, _Traits>& __is,
+	       std::cauchy_distribution<_RealType>& __x);
+
+
+  /**
+   * @brief A fisher_f_distribution random number distribution.
+   *
+   * The formula for the normal probability mass function is
+   * @f[
+   *     p(x|m,n) = \frac{\Gamma((m+n)/2)}{\Gamma(m/2)\Gamma(n/2)}
+   *                (\frac{m}{n})^{m/2} x^{(m/2)-1}
+   *                (1 + \frac{mx}{n})^{-(m+n)/2} 
+   * @f]
+   */
+  template<typename _RealType = double>
+    class fisher_f_distribution
+    {
+      static_assert(std::is_floating_point<_RealType>::value,
+		    "result_type must be a floating point type");
+
+    public:
+      /** The type of the range of the distribution. */
+      typedef _RealType result_type;
+
+      /** Parameter type. */
+      struct param_type
+      {
+	typedef fisher_f_distribution<_RealType> distribution_type;
+
+	param_type() : param_type(1) { }
+
+	explicit
+	param_type(_RealType __m, _RealType __n = _RealType(1))
+	: _M_m(__m), _M_n(__n)
+	{ }
+
+	_RealType
+	m() const
+	{ return _M_m; }
+
+	_RealType
+	n() const
+	{ return _M_n; }
+
+	friend bool
+	operator==(const param_type& __p1, const param_type& __p2)
+	{ return __p1._M_m == __p2._M_m && __p1._M_n == __p2._M_n; }
+
+	friend bool
+	operator!=(const param_type& __p1, const param_type& __p2)
+	{ return !(__p1 == __p2); }
+
+      private:
+	_RealType _M_m;
+	_RealType _M_n;
+      };
+
+      fisher_f_distribution() : fisher_f_distribution(1.0) { }
+
+      explicit
+      fisher_f_distribution(_RealType __m,
+			    _RealType __n = _RealType(1))
+      : _M_param(__m, __n), _M_gd_x(__m / 2), _M_gd_y(__n / 2)
+      { }
+
+      explicit
+      fisher_f_distribution(const param_type& __p)
+      : _M_param(__p), _M_gd_x(__p.m() / 2), _M_gd_y(__p.n() / 2)
+      { }
+
+      /**
+       * @brief Resets the distribution state.
+       */
+      void
+      reset()
+      {
+	_M_gd_x.reset();
+	_M_gd_y.reset();
+      }
+
+      /**
+       *
+       */
+      _RealType
+      m() const
+      { return _M_param.m(); }
+
+      _RealType
+      n() const
+      { return _M_param.n(); }
+
+      /**
+       * @brief Returns the parameter set of the distribution.
+       */
+      param_type
+      param() const
+      { return _M_param; }
+
+      /**
+       * @brief Sets the parameter set of the distribution.
+       * @param __param The new parameter set of the distribution.
+       */
+      void
+      param(const param_type& __param)
+      { _M_param = __param; }
+
+      /**
+       * @brief Returns the greatest lower bound value of the distribution.
+       */
+      result_type
+      min() const
+      { return result_type(0); }
+
+      /**
+       * @brief Returns the least upper bound value of the distribution.
+       */
+      result_type
+      max() const
+      { return std::numeric_limits<result_type>::max(); }
+
+      /**
+       * @brief Generating functions.
+       */
+      template<typename _UniformRandomNumberGenerator>
+	result_type
+	operator()(_UniformRandomNumberGenerator& __urng)
+	{ return (_M_gd_x(__urng) * n()) / (_M_gd_y(__urng) * m()); }
+
+      template<typename _UniformRandomNumberGenerator>
+	result_type
+	operator()(_UniformRandomNumberGenerator& __urng,
+		   const param_type& __p)
+        {
+	  typedef typename std::gamma_distribution<result_type>::param_type
+	    param_type;
+	  return ((_M_gd_x(__urng, param_type(__p.m() / 2)) * n())
+		  / (_M_gd_y(__urng, param_type(__p.n() / 2)) * m()));
+	}
+
+      template<typename _ForwardIterator,
+	       typename _UniformRandomNumberGenerator>
+	void
+	__generate(_ForwardIterator __f, _ForwardIterator __t,
+		   _UniformRandomNumberGenerator& __urng)
+	{ this->__generate_impl(__f, __t, __urng); }
+
+      template<typename _ForwardIterator,
+	       typename _UniformRandomNumberGenerator>
+	void
+	__generate(_ForwardIterator __f, _ForwardIterator __t,
+		   _UniformRandomNumberGenerator& __urng,
+		   const param_type& __p)
+	{ this->__generate_impl(__f, __t, __urng, __p); }
+
+      template<typename _UniformRandomNumberGenerator>
+	void
+	__generate(result_type* __f, result_type* __t,
+		   _UniformRandomNumberGenerator& __urng)
+	{ this->__generate_impl(__f, __t, __urng); }
+
+      template<typename _UniformRandomNumberGenerator>
+	void
+	__generate(result_type* __f, result_type* __t,
+		   _UniformRandomNumberGenerator& __urng,
+		   const param_type& __p)
+	{ this->__generate_impl(__f, __t, __urng, __p); }
+
+      /**
+       * @brief Return true if two Fisher f distributions have
+       *        the same parameters and the sequences that would
+       *        be generated are equal.
+       */
+      friend bool
+      operator==(const fisher_f_distribution& __d1,
+		 const fisher_f_distribution& __d2)
+      { return (__d1._M_param == __d2._M_param
+		&& __d1._M_gd_x == __d2._M_gd_x
+		&& __d1._M_gd_y == __d2._M_gd_y); }
+
+      /**
+       * @brief Inserts a %fisher_f_distribution random number distribution
+       * @p __x into the output stream @p __os.
+       *
+       * @param __os An output stream.
+       * @param __x  A %fisher_f_distribution random number distribution.
+       *
+       * @returns The output stream with the state of @p __x inserted or in
+       * an error state.
+       */
+      template<typename _RealType1, typename _CharT, typename _Traits>
+	friend std::basic_ostream<_CharT, _Traits>&
+	operator<<(std::basic_ostream<_CharT, _Traits>& __os,
+		   const std::fisher_f_distribution<_RealType1>& __x);
+
+      /**
+       * @brief Extracts a %fisher_f_distribution random number distribution
+       * @p __x from the input stream @p __is.
+       *
+       * @param __is An input stream.
+       * @param __x A %fisher_f_distribution random number
+       *            generator engine.
+       *
+       * @returns The input stream with @p __x extracted or in an error state.
+       */
+      template<typename _RealType1, typename _CharT, typename _Traits>
+	friend std::basic_istream<_CharT, _Traits>&
+	operator>>(std::basic_istream<_CharT, _Traits>& __is,
+		   std::fisher_f_distribution<_RealType1>& __x);
+
+    private:
+      template<typename _ForwardIterator,
+	       typename _UniformRandomNumberGenerator>
+	void
+	__generate_impl(_ForwardIterator __f, _ForwardIterator __t,
+			_UniformRandomNumberGenerator& __urng);
+
+      template<typename _ForwardIterator,
+	       typename _UniformRandomNumberGenerator>
+	void
+	__generate_impl(_ForwardIterator __f, _ForwardIterator __t,
+			_UniformRandomNumberGenerator& __urng,
+			const param_type& __p);
+
+      param_type _M_param;
+
+      std::gamma_distribution<result_type> _M_gd_x, _M_gd_y;
+    };
+
+  /**
+   * @brief Return true if two Fisher f distributions are different.
+   */
+  template<typename _RealType>
+    inline bool
+    operator!=(const std::fisher_f_distribution<_RealType>& __d1,
+	       const std::fisher_f_distribution<_RealType>& __d2)
+    { return !(__d1 == __d2); }
+
+  /**
+   * @brief A student_t_distribution random number distribution.
+   *
+   * The formula for the normal probability mass function is:
+   * @f[
+   *     p(x|n) = \frac{1}{\sqrt(n\pi)} \frac{\Gamma((n+1)/2)}{\Gamma(n/2)}
+   *              (1 + \frac{x^2}{n}) ^{-(n+1)/2} 
+   * @f]
+   */
+  template<typename _RealType = double>
+    class student_t_distribution
+    {
+      static_assert(std::is_floating_point<_RealType>::value,
+		    "result_type must be a floating point type");
+
+    public:
+      /** The type of the range of the distribution. */
+      typedef _RealType result_type;
+
+      /** Parameter type. */
+      struct param_type
+      {
+	typedef student_t_distribution<_RealType> distribution_type;
+
+	param_type() : param_type(1) { }
+
+	explicit
+	param_type(_RealType __n)
+	: _M_n(__n)
+	{ }
+
+	_RealType
+	n() const
+	{ return _M_n; }
+
+	friend bool
+	operator==(const param_type& __p1, const param_type& __p2)
+	{ return __p1._M_n == __p2._M_n; }
+
+	friend bool
+	operator!=(const param_type& __p1, const param_type& __p2)
+	{ return !(__p1 == __p2); }
+
+      private:
+	_RealType _M_n;
+      };
+
+      student_t_distribution() : student_t_distribution(1.0) { }
+
+      explicit
+      student_t_distribution(_RealType __n)
+      : _M_param(__n), _M_nd(), _M_gd(__n / 2, 2)
+      { }
+
+      explicit
+      student_t_distribution(const param_type& __p)
+      : _M_param(__p), _M_nd(), _M_gd(__p.n() / 2, 2)
+      { }
+
+      /**
+       * @brief Resets the distribution state.
+       */
+      void
+      reset()
+      {
+	_M_nd.reset();
+	_M_gd.reset();
+      }
+
+      /**
+       *
+       */
+      _RealType
+      n() const
+      { return _M_param.n(); }
+
+      /**
+       * @brief Returns the parameter set of the distribution.
+       */
+      param_type
+      param() const
+      { return _M_param; }
+
+      /**
+       * @brief Sets the parameter set of the distribution.
+       * @param __param The new parameter set of the distribution.
+       */
+      void
+      param(const param_type& __param)
+      { _M_param = __param; }
+
+      /**
+       * @brief Returns the greatest lower bound value of the distribution.
+       */
+      result_type
+      min() const
+      { return std::numeric_limits<result_type>::lowest(); }
+
+      /**
+       * @brief Returns the least upper bound value of the distribution.
+       */
+      result_type
+      max() const
+      { return std::numeric_limits<result_type>::max(); }
+
+      /**
+       * @brief Generating functions.
+       */
+      template<typename _UniformRandomNumberGenerator>
+	result_type
+        operator()(_UniformRandomNumberGenerator& __urng)
+        { return _M_nd(__urng) * std::sqrt(n() / _M_gd(__urng)); }
+
+      template<typename _UniformRandomNumberGenerator>
+	result_type
+	operator()(_UniformRandomNumberGenerator& __urng,
+		   const param_type& __p)
+        {
+	  typedef typename std::gamma_distribution<result_type>::param_type
+	    param_type;
+	
+	  const result_type __g = _M_gd(__urng, param_type(__p.n() / 2, 2));
+	  return _M_nd(__urng) * std::sqrt(__p.n() / __g);
+        }
+
+      template<typename _ForwardIterator,
+	       typename _UniformRandomNumberGenerator>
+	void
+	__generate(_ForwardIterator __f, _ForwardIterator __t,
+		   _UniformRandomNumberGenerator& __urng)
+	{ this->__generate_impl(__f, __t, __urng); }
+
+      template<typename _ForwardIterator,
+	       typename _UniformRandomNumberGenerator>
+	void
+	__generate(_ForwardIterator __f, _ForwardIterator __t,
+		   _UniformRandomNumberGenerator& __urng,
+		   const param_type& __p)
+	{ this->__generate_impl(__f, __t, __urng, __p); }
+
+      template<typename _UniformRandomNumberGenerator>
+	void
+	__generate(result_type* __f, result_type* __t,
+		   _UniformRandomNumberGenerator& __urng)
+	{ this->__generate_impl(__f, __t, __urng); }
+
+      template<typename _UniformRandomNumberGenerator>
+	void
+	__generate(result_type* __f, result_type* __t,
+		   _UniformRandomNumberGenerator& __urng,
+		   const param_type& __p)
+	{ this->__generate_impl(__f, __t, __urng, __p); }
+
+      /**
+       * @brief Return true if two Student t distributions have
+       *        the same parameters and the sequences that would
+       *        be generated are equal.
+       */
+      friend bool
+      operator==(const student_t_distribution& __d1,
+		 const student_t_distribution& __d2)
+      { return (__d1._M_param == __d2._M_param
+		&& __d1._M_nd == __d2._M_nd && __d1._M_gd == __d2._M_gd); }
+
+      /**
+       * @brief Inserts a %student_t_distribution random number distribution
+       * @p __x into the output stream @p __os.
+       *
+       * @param __os An output stream.
+       * @param __x  A %student_t_distribution random number distribution.
+       *
+       * @returns The output stream with the state of @p __x inserted or in
+       * an error state.
+       */
+      template<typename _RealType1, typename _CharT, typename _Traits>
+	friend std::basic_ostream<_CharT, _Traits>&
+	operator<<(std::basic_ostream<_CharT, _Traits>& __os,
+		   const std::student_t_distribution<_RealType1>& __x);
+
+      /**
+       * @brief Extracts a %student_t_distribution random number distribution
+       * @p __x from the input stream @p __is.
+       *
+       * @param __is An input stream.
+       * @param __x A %student_t_distribution random number
+       *            generator engine.
+       *
+       * @returns The input stream with @p __x extracted or in an error state.
+       */
+      template<typename _RealType1, typename _CharT, typename _Traits>
+	friend std::basic_istream<_CharT, _Traits>&
+	operator>>(std::basic_istream<_CharT, _Traits>& __is,
+		   std::student_t_distribution<_RealType1>& __x);
+
+    private:
+      template<typename _ForwardIterator,
+	       typename _UniformRandomNumberGenerator>
+	void
+	__generate_impl(_ForwardIterator __f, _ForwardIterator __t,
+			_UniformRandomNumberGenerator& __urng);
+      template<typename _ForwardIterator,
+	       typename _UniformRandomNumberGenerator>
+	void
+	__generate_impl(_ForwardIterator __f, _ForwardIterator __t,
+			_UniformRandomNumberGenerator& __urng,
+			const param_type& __p);
+
+      param_type _M_param;
+
+      std::normal_distribution<result_type> _M_nd;
+      std::gamma_distribution<result_type> _M_gd;
+    };
+
+  /**
+   * @brief Return true if two Student t distributions are different.
+   */
+  template<typename _RealType>
+    inline bool
+    operator!=(const std::student_t_distribution<_RealType>& __d1,
+	       const std::student_t_distribution<_RealType>& __d2)
+    { return !(__d1 == __d2); }
+
+
+  /// @} group random_distributions_normal
+
+  /**
+   * @addtogroup random_distributions_bernoulli Bernoulli Distributions
+   * @ingroup random_distributions
+   * @{
+   */
+
+  /**
+   * @brief A Bernoulli random number distribution.
+   *
+   * Generates a sequence of true and false values with likelihood @f$p@f$
+   * that true will come up and @f$(1 - p)@f$ that false will appear.
+   */
+  class bernoulli_distribution
+  {
+  public:
+    /** The type of the range of the distribution. */
+    typedef bool result_type;
+
+    /** Parameter type. */
+    struct param_type
+    {
+      typedef bernoulli_distribution distribution_type;
+
+      param_type() : param_type(0.5) { }
+
+      explicit
+      param_type(double __p)
+      : _M_p(__p)
+      {
+	__glibcxx_assert((_M_p >= 0.0) && (_M_p <= 1.0));
+      }
+
+      double
+      p() const
+      { return _M_p; }
+
+      friend bool
+      operator==(const param_type& __p1, const param_type& __p2)
+      { return __p1._M_p == __p2._M_p; }
+
+      friend bool
+      operator!=(const param_type& __p1, const param_type& __p2)
+      { return !(__p1 == __p2); }
+
+    private:
+      double _M_p;
+    };
+
+  public:
+    /**
+     * @brief Constructs a Bernoulli distribution with likelihood 0.5.
+     */
+    bernoulli_distribution() : bernoulli_distribution(0.5) { }
+
+    /**
+     * @brief Constructs a Bernoulli distribution with likelihood @p p.
+     *
+     * @param __p  [IN]  The likelihood of a true result being returned.
+     *                   Must be in the interval @f$[0, 1]@f$.
+     */
+    explicit
+    bernoulli_distribution(double __p)
+    : _M_param(__p)
+    { }
+
+    explicit
+    bernoulli_distribution(const param_type& __p)
+    : _M_param(__p)
+    { }
+
+    /**
+     * @brief Resets the distribution state.
+     *
+     * Does nothing for a Bernoulli distribution.
+     */
+    void
+    reset() { }
+
+    /**
+     * @brief Returns the @p p parameter of the distribution.
+     */
+    double
+    p() const
+    { return _M_param.p(); }
+
+    /**
+     * @brief Returns the parameter set of the distribution.
+     */
+    param_type
+    param() const
+    { return _M_param; }
+
+    /**
+     * @brief Sets the parameter set of the distribution.
+     * @param __param The new parameter set of the distribution.
+     */
+    void
+    param(const param_type& __param)
+    { _M_param = __param; }
+
+    /**
+     * @brief Returns the greatest lower bound value of the distribution.
+     */
+    result_type
+    min() const
+    { return std::numeric_limits<result_type>::min(); }
+
+    /**
+     * @brief Returns the least upper bound value of the distribution.
+     */
+    result_type
+    max() const
+    { return std::numeric_limits<result_type>::max(); }
+
+    /**
+     * @brief Generating functions.
+     */
+    template<typename _UniformRandomNumberGenerator>
+      result_type
+      operator()(_UniformRandomNumberGenerator& __urng)
+      { return this->operator()(__urng, _M_param); }
+
+    template<typename _UniformRandomNumberGenerator>
+      result_type
+      operator()(_UniformRandomNumberGenerator& __urng,
+		 const param_type& __p)
+      {
+	__detail::_Adaptor<_UniformRandomNumberGenerator, double>
+	  __aurng(__urng);
+	if ((__aurng() - __aurng.min())
+	     < __p.p() * (__aurng.max() - __aurng.min()))
+	  return true;
+	return false;
+      }
+
+    template<typename _ForwardIterator,
+	     typename _UniformRandomNumberGenerator>
+      void
+      __generate(_ForwardIterator __f, _ForwardIterator __t,
+		 _UniformRandomNumberGenerator& __urng)
+      { this->__generate(__f, __t, __urng, _M_param); }
+
+    template<typename _ForwardIterator,
+	     typename _UniformRandomNumberGenerator>
+      void
+      __generate(_ForwardIterator __f, _ForwardIterator __t,
+		 _UniformRandomNumberGenerator& __urng, const param_type& __p)
+      { this->__generate_impl(__f, __t, __urng, __p); }
+
+    template<typename _UniformRandomNumberGenerator>
+      void
+      __generate(result_type* __f, result_type* __t,
+		 _UniformRandomNumberGenerator& __urng,
+		 const param_type& __p)
+      { this->__generate_impl(__f, __t, __urng, __p); }
+
+    /**
+     * @brief Return true if two Bernoulli distributions have
+     *        the same parameters.
+     */
+    friend bool
+    operator==(const bernoulli_distribution& __d1,
+	       const bernoulli_distribution& __d2)
+    { return __d1._M_param == __d2._M_param; }
+
+  private:
+    template<typename _ForwardIterator,
+	     typename _UniformRandomNumberGenerator>
+      void
+      __generate_impl(_ForwardIterator __f, _ForwardIterator __t,
+		      _UniformRandomNumberGenerator& __urng,
+		      const param_type& __p);
+
+    param_type _M_param;
+  };
+
+  /**
+   * @brief Return true if two Bernoulli distributions have
+   *        different parameters.
+   */
+  inline bool
+  operator!=(const std::bernoulli_distribution& __d1,
+	     const std::bernoulli_distribution& __d2)
+  { return !(__d1 == __d2); }
+
+  /**
+   * @brief Inserts a %bernoulli_distribution random number distribution
+   * @p __x into the output stream @p __os.
+   *
+   * @param __os An output stream.
+   * @param __x  A %bernoulli_distribution random number distribution.
+   *
+   * @returns The output stream with the state of @p __x inserted or in
+   * an error state.
+   */
+  template<typename _CharT, typename _Traits>
+    std::basic_ostream<_CharT, _Traits>&
+    operator<<(std::basic_ostream<_CharT, _Traits>& __os,
+	       const std::bernoulli_distribution& __x);
+
+  /**
+   * @brief Extracts a %bernoulli_distribution random number distribution
+   * @p __x from the input stream @p __is.
+   *
+   * @param __is An input stream.
+   * @param __x  A %bernoulli_distribution random number generator engine.
+   *
+   * @returns The input stream with @p __x extracted or in an error state.
+   */
+  template<typename _CharT, typename _Traits>
+    inline std::basic_istream<_CharT, _Traits>&
+    operator>>(std::basic_istream<_CharT, _Traits>& __is,
+	       std::bernoulli_distribution& __x)
+    {
+      double __p;
+      if (__is >> __p)
+	__x.param(bernoulli_distribution::param_type(__p));
+      return __is;
+    }
+
+
+  /**
+   * @brief A discrete binomial random number distribution.
+   *
+   * The formula for the binomial probability density function is
+   * @f$p(i|t,p) = \binom{t}{i} p^i (1 - p)^{t - i}@f$ where @f$t@f$
+   * and @f$p@f$ are the parameters of the distribution.
+   */
+  template<typename _IntType = int>
+    class binomial_distribution
+    {
+      static_assert(std::is_integral<_IntType>::value,
+		    "result_type must be an integral type");
+
+    public:
+      /** The type of the range of the distribution. */
+      typedef _IntType result_type;
+
+      /** Parameter type. */
+      struct param_type
+      {
+	typedef binomial_distribution<_IntType> distribution_type;
+	friend class binomial_distribution<_IntType>;
+
+	param_type() : param_type(1) { }
+
+	explicit
+	param_type(_IntType __t, double __p = 0.5)
+	: _M_t(__t), _M_p(__p)
+	{
+	  __glibcxx_assert((_M_t >= _IntType(0))
+				&& (_M_p >= 0.0)
+				&& (_M_p <= 1.0));
+	  _M_initialize();
+	}
+
+	_IntType
+	t() const
+	{ return _M_t; }
+
+	double
+	p() const
+	{ return _M_p; }
+
+	friend bool
+	operator==(const param_type& __p1, const param_type& __p2)
+	{ return __p1._M_t == __p2._M_t && __p1._M_p == __p2._M_p; }
+
+	friend bool
+	operator!=(const param_type& __p1, const param_type& __p2)
+	{ return !(__p1 == __p2); }
+
+      private:
+	void
+	_M_initialize();
+
+	_IntType _M_t;
+	double _M_p;
+
+	double _M_q;
+#if _GLIBCXX_USE_C99_MATH_TR1
+	double _M_d1, _M_d2, _M_s1, _M_s2, _M_c,
+	       _M_a1, _M_a123, _M_s, _M_lf, _M_lp1p;
+#endif
+	bool   _M_easy;
+      };
+
+      // constructors and member functions
+
+      binomial_distribution() : binomial_distribution(1) { }
+
+      explicit
+      binomial_distribution(_IntType __t, double __p = 0.5)
+      : _M_param(__t, __p), _M_nd()
+      { }
+
+      explicit
+      binomial_distribution(const param_type& __p)
+      : _M_param(__p), _M_nd()
+      { }
+
+      /**
+       * @brief Resets the distribution state.
+       */
+      void
+      reset()
+      { _M_nd.reset(); }
+
+      /**
+       * @brief Returns the distribution @p t parameter.
+       */
+      _IntType
+      t() const
+      { return _M_param.t(); }
+
+      /**
+       * @brief Returns the distribution @p p parameter.
+       */
+      double
+      p() const
+      { return _M_param.p(); }
+
+      /**
+       * @brief Returns the parameter set of the distribution.
+       */
+      param_type
+      param() const
+      { return _M_param; }
+
+      /**
+       * @brief Sets the parameter set of the distribution.
+       * @param __param The new parameter set of the distribution.
+       */
+      void
+      param(const param_type& __param)
+      { _M_param = __param; }
+
+      /**
+       * @brief Returns the greatest lower bound value of the distribution.
+       */
+      result_type
+      min() const
+      { return 0; }
+
+      /**
+       * @brief Returns the least upper bound value of the distribution.
+       */
+      result_type
+      max() const
+      { return _M_param.t(); }
+
+      /**
+       * @brief Generating functions.
+       */
+      template<typename _UniformRandomNumberGenerator>
+	result_type
+	operator()(_UniformRandomNumberGenerator& __urng)
+	{ return this->operator()(__urng, _M_param); }
+
+      template<typename _UniformRandomNumberGenerator>
+	result_type
+	operator()(_UniformRandomNumberGenerator& __urng,
+		   const param_type& __p);
+
+      template<typename _ForwardIterator,
+	       typename _UniformRandomNumberGenerator>
+	void
+	__generate(_ForwardIterator __f, _ForwardIterator __t,
+		   _UniformRandomNumberGenerator& __urng)
+	{ this->__generate(__f, __t, __urng, _M_param); }
+
+      template<typename _ForwardIterator,
+	       typename _UniformRandomNumberGenerator>
+	void
+	__generate(_ForwardIterator __f, _ForwardIterator __t,
+		   _UniformRandomNumberGenerator& __urng,
+		   const param_type& __p)
+	{ this->__generate_impl(__f, __t, __urng, __p); }
+
+      template<typename _UniformRandomNumberGenerator>
+	void
+	__generate(result_type* __f, result_type* __t,
+		   _UniformRandomNumberGenerator& __urng,
+		   const param_type& __p)
+	{ this->__generate_impl(__f, __t, __urng, __p); }
+
+      /**
+       * @brief Return true if two binomial distributions have
+       *        the same parameters and the sequences that would
+       *        be generated are equal.
+       */
+	friend bool
+        operator==(const binomial_distribution& __d1,
+		   const binomial_distribution& __d2)
+#ifdef _GLIBCXX_USE_C99_MATH_TR1
+	{ return __d1._M_param == __d2._M_param && __d1._M_nd == __d2._M_nd; }
+#else
+        { return __d1._M_param == __d2._M_param; }
+#endif
+
+      /**
+       * @brief Inserts a %binomial_distribution random number distribution
+       * @p __x into the output stream @p __os.
+       *
+       * @param __os An output stream.
+       * @param __x  A %binomial_distribution random number distribution.
+       *
+       * @returns The output stream with the state of @p __x inserted or in
+       * an error state.
+       */
+      template<typename _IntType1,
+	       typename _CharT, typename _Traits>
+	friend std::basic_ostream<_CharT, _Traits>&
+	operator<<(std::basic_ostream<_CharT, _Traits>& __os,
+		   const std::binomial_distribution<_IntType1>& __x);
+
+      /**
+       * @brief Extracts a %binomial_distribution random number distribution
+       * @p __x from the input stream @p __is.
+       *
+       * @param __is An input stream.
+       * @param __x  A %binomial_distribution random number generator engine.
+       *
+       * @returns The input stream with @p __x extracted or in an error
+       *          state.
+       */
+      template<typename _IntType1,
+	       typename _CharT, typename _Traits>
+	friend std::basic_istream<_CharT, _Traits>&
+	operator>>(std::basic_istream<_CharT, _Traits>& __is,
+		   std::binomial_distribution<_IntType1>& __x);
+
+    private:
+      template<typename _ForwardIterator,
+	       typename _UniformRandomNumberGenerator>
+	void
+	__generate_impl(_ForwardIterator __f, _ForwardIterator __t,
+			_UniformRandomNumberGenerator& __urng,
+			const param_type& __p);
+
+      template<typename _UniformRandomNumberGenerator>
+	result_type
+	_M_waiting(_UniformRandomNumberGenerator& __urng,
+		   _IntType __t, double __q);
+
+      param_type _M_param;
+
+      // NB: Unused when _GLIBCXX_USE_C99_MATH_TR1 is undefined.
+      std::normal_distribution<double> _M_nd;
+    };
+
+  /**
+   * @brief Return true if two binomial distributions are different.
+   */
+  template<typename _IntType>
+    inline bool
+    operator!=(const std::binomial_distribution<_IntType>& __d1,
+	       const std::binomial_distribution<_IntType>& __d2)
+    { return !(__d1 == __d2); }
+
+
+  /**
+   * @brief A discrete geometric random number distribution.
+   *
+   * The formula for the geometric probability density function is
+   * @f$p(i|p) = p(1 - p)^{i}@f$ where @f$p@f$ is the parameter of the
+   * distribution.
+   */
+  template<typename _IntType = int>
+    class geometric_distribution
+    {
+      static_assert(std::is_integral<_IntType>::value,
+		    "result_type must be an integral type");
+
+    public:
+      /** The type of the range of the distribution. */
+      typedef _IntType  result_type;
+
+      /** Parameter type. */
+      struct param_type
+      {
+	typedef geometric_distribution<_IntType> distribution_type;
+	friend class geometric_distribution<_IntType>;
+
+	param_type() : param_type(0.5) { }
+
+	explicit
+	param_type(double __p)
+	: _M_p(__p)
+	{
+	  __glibcxx_assert((_M_p > 0.0) && (_M_p < 1.0));
+	  _M_initialize();
+	}
+
+	double
+	p() const
+	{ return _M_p; }
+
+	friend bool
+	operator==(const param_type& __p1, const param_type& __p2)
+	{ return __p1._M_p == __p2._M_p; }
+
+	friend bool
+	operator!=(const param_type& __p1, const param_type& __p2)
+	{ return !(__p1 == __p2); }
+
+      private:
+	void
+	_M_initialize()
+	{ _M_log_1_p = std::log(1.0 - _M_p); }
+
+	double _M_p;
+
+	double _M_log_1_p;
+      };
+
+      // constructors and member functions
+
+      geometric_distribution() : geometric_distribution(0.5) { }
+
+      explicit
+      geometric_distribution(double __p)
+      : _M_param(__p)
+      { }
+
+      explicit
+      geometric_distribution(const param_type& __p)
+      : _M_param(__p)
+      { }
+
+      /**
+       * @brief Resets the distribution state.
+       *
+       * Does nothing for the geometric distribution.
+       */
+      void
+      reset() { }
+
+      /**
+       * @brief Returns the distribution parameter @p p.
+       */
+      double
+      p() const
+      { return _M_param.p(); }
+
+      /**
+       * @brief Returns the parameter set of the distribution.
+       */
+      param_type
+      param() const
+      { return _M_param; }
+
+      /**
+       * @brief Sets the parameter set of the distribution.
+       * @param __param The new parameter set of the distribution.
+       */
+      void
+      param(const param_type& __param)
+      { _M_param = __param; }
+
+      /**
+       * @brief Returns the greatest lower bound value of the distribution.
+       */
+      result_type
+      min() const
+      { return 0; }
+
+      /**
+       * @brief Returns the least upper bound value of the distribution.
+       */
+      result_type
+      max() const
+      { return std::numeric_limits<result_type>::max(); }
+
+      /**
+       * @brief Generating functions.
+       */
+      template<typename _UniformRandomNumberGenerator>
+	result_type
+	operator()(_UniformRandomNumberGenerator& __urng)
+	{ return this->operator()(__urng, _M_param); }
+
+      template<typename _UniformRandomNumberGenerator>
+	result_type
+	operator()(_UniformRandomNumberGenerator& __urng,
+		   const param_type& __p);
+
+      template<typename _ForwardIterator,
+	       typename _UniformRandomNumberGenerator>
+	void
+	__generate(_ForwardIterator __f, _ForwardIterator __t,
+		   _UniformRandomNumberGenerator& __urng)
+	{ this->__generate(__f, __t, __urng, _M_param); }
+
+      template<typename _ForwardIterator,
+	       typename _UniformRandomNumberGenerator>
+	void
+	__generate(_ForwardIterator __f, _ForwardIterator __t,
+		   _UniformRandomNumberGenerator& __urng,
+		   const param_type& __p)
+	{ this->__generate_impl(__f, __t, __urng, __p); }
+
+      template<typename _UniformRandomNumberGenerator>
+	void
+	__generate(result_type* __f, result_type* __t,
+		   _UniformRandomNumberGenerator& __urng,
+		   const param_type& __p)
+	{ this->__generate_impl(__f, __t, __urng, __p); }
+
+      /**
+       * @brief Return true if two geometric distributions have
+       *        the same parameters.
+       */
+      friend bool
+      operator==(const geometric_distribution& __d1,
+		 const geometric_distribution& __d2)
+      { return __d1._M_param == __d2._M_param; }
+
+    private:
+      template<typename _ForwardIterator,
+	       typename _UniformRandomNumberGenerator>
+	void
+	__generate_impl(_ForwardIterator __f, _ForwardIterator __t,
+			_UniformRandomNumberGenerator& __urng,
+			const param_type& __p);
+
+      param_type _M_param;
+    };
+
+  /**
+   * @brief Return true if two geometric distributions have
+   *        different parameters.
+   */
+  template<typename _IntType>
+    inline bool
+    operator!=(const std::geometric_distribution<_IntType>& __d1,
+	       const std::geometric_distribution<_IntType>& __d2)
+    { return !(__d1 == __d2); }
+
+  /**
+   * @brief Inserts a %geometric_distribution random number distribution
+   * @p __x into the output stream @p __os.
+   *
+   * @param __os An output stream.
+   * @param __x  A %geometric_distribution random number distribution.
+   *
+   * @returns The output stream with the state of @p __x inserted or in
+   * an error state.
+   */
+  template<typename _IntType,
+	   typename _CharT, typename _Traits>
+    std::basic_ostream<_CharT, _Traits>&
+    operator<<(std::basic_ostream<_CharT, _Traits>& __os,
+	       const std::geometric_distribution<_IntType>& __x);
+
+  /**
+   * @brief Extracts a %geometric_distribution random number distribution
+   * @p __x from the input stream @p __is.
+   *
+   * @param __is An input stream.
+   * @param __x  A %geometric_distribution random number generator engine.
+   *
+   * @returns The input stream with @p __x extracted or in an error state.
+   */
+  template<typename _IntType,
+	   typename _CharT, typename _Traits>
+    std::basic_istream<_CharT, _Traits>&
+    operator>>(std::basic_istream<_CharT, _Traits>& __is,
+	       std::geometric_distribution<_IntType>& __x);
+
+
+  /**
+   * @brief A negative_binomial_distribution random number distribution.
+   *
+   * The formula for the negative binomial probability mass function is
+   * @f$p(i) = \binom{n}{i} p^i (1 - p)^{t - i}@f$ where @f$t@f$
+   * and @f$p@f$ are the parameters of the distribution.
+   */
+  template<typename _IntType = int>
+    class negative_binomial_distribution
+    {
+      static_assert(std::is_integral<_IntType>::value,
+		    "result_type must be an integral type");
+
+    public:
+      /** The type of the range of the distribution. */
+      typedef _IntType result_type;
+
+      /** Parameter type. */
+      struct param_type
+      {
+	typedef negative_binomial_distribution<_IntType> distribution_type;
+
+	param_type() : param_type(1) { }
+
+	explicit
+	param_type(_IntType __k, double __p = 0.5)
+	: _M_k(__k), _M_p(__p)
+	{
+	  __glibcxx_assert((_M_k > 0) && (_M_p > 0.0) && (_M_p <= 1.0));
+	}
+
+	_IntType
+	k() const
+	{ return _M_k; }
+
+	double
+	p() const
+	{ return _M_p; }
+
+	friend bool
+	operator==(const param_type& __p1, const param_type& __p2)
+	{ return __p1._M_k == __p2._M_k && __p1._M_p == __p2._M_p; }
+
+	friend bool
+	operator!=(const param_type& __p1, const param_type& __p2)
+	{ return !(__p1 == __p2); }
+
+      private:
+	_IntType _M_k;
+	double _M_p;
+      };
+
+      negative_binomial_distribution() : negative_binomial_distribution(1) { }
+
+      explicit
+      negative_binomial_distribution(_IntType __k, double __p = 0.5)
+      : _M_param(__k, __p), _M_gd(__k, (1.0 - __p) / __p)
+      { }
+
+      explicit
+      negative_binomial_distribution(const param_type& __p)
+      : _M_param(__p), _M_gd(__p.k(), (1.0 - __p.p()) / __p.p())
+      { }
+
+      /**
+       * @brief Resets the distribution state.
+       */
+      void
+      reset()
+      { _M_gd.reset(); }
+
+      /**
+       * @brief Return the @f$k@f$ parameter of the distribution.
+       */
+      _IntType
+      k() const
+      { return _M_param.k(); }
+
+      /**
+       * @brief Return the @f$p@f$ parameter of the distribution.
+       */
+      double
+      p() const
+      { return _M_param.p(); }
+
+      /**
+       * @brief Returns the parameter set of the distribution.
+       */
+      param_type
+      param() const
+      { return _M_param; }
+
+      /**
+       * @brief Sets the parameter set of the distribution.
+       * @param __param The new parameter set of the distribution.
+       */
+      void
+      param(const param_type& __param)
+      { _M_param = __param; }
+
+      /**
+       * @brief Returns the greatest lower bound value of the distribution.
+       */
+      result_type
+      min() const
+      { return result_type(0); }
+
+      /**
+       * @brief Returns the least upper bound value of the distribution.
+       */
+      result_type
+      max() const
+      { return std::numeric_limits<result_type>::max(); }
+
+      /**
+       * @brief Generating functions.
+       */
+      template<typename _UniformRandomNumberGenerator>
+	result_type
+        operator()(_UniformRandomNumberGenerator& __urng);
+
+      template<typename _UniformRandomNumberGenerator>
+	result_type
+	operator()(_UniformRandomNumberGenerator& __urng,
+		   const param_type& __p);
+
+      template<typename _ForwardIterator,
+	       typename _UniformRandomNumberGenerator>
+	void
+	__generate(_ForwardIterator __f, _ForwardIterator __t,
+		   _UniformRandomNumberGenerator& __urng)
+	{ this->__generate_impl(__f, __t, __urng); }
+
+      template<typename _ForwardIterator,
+	       typename _UniformRandomNumberGenerator>
+	void
+	__generate(_ForwardIterator __f, _ForwardIterator __t,
+		   _UniformRandomNumberGenerator& __urng,
+		   const param_type& __p)
+	{ this->__generate_impl(__f, __t, __urng, __p); }
+
+      template<typename _UniformRandomNumberGenerator>
+	void
+	__generate(result_type* __f, result_type* __t,
+		   _UniformRandomNumberGenerator& __urng)
+	{ this->__generate_impl(__f, __t, __urng); }
+
+      template<typename _UniformRandomNumberGenerator>
+	void
+	__generate(result_type* __f, result_type* __t,
+		   _UniformRandomNumberGenerator& __urng,
+		   const param_type& __p)
+	{ this->__generate_impl(__f, __t, __urng, __p); }
+
+      /**
+       * @brief Return true if two negative binomial distributions have
+       *        the same parameters and the sequences that would be
+       *        generated are equal.
+       */
+      friend bool
+      operator==(const negative_binomial_distribution& __d1,
+		 const negative_binomial_distribution& __d2)
+      { return __d1._M_param == __d2._M_param && __d1._M_gd == __d2._M_gd; }
+
+      /**
+       * @brief Inserts a %negative_binomial_distribution random
+       *        number distribution @p __x into the output stream @p __os.
+       *
+       * @param __os An output stream.
+       * @param __x  A %negative_binomial_distribution random number
+       *             distribution.
+       *
+       * @returns The output stream with the state of @p __x inserted or in
+       *          an error state.
+       */
+      template<typename _IntType1, typename _CharT, typename _Traits>
+	friend std::basic_ostream<_CharT, _Traits>&
+	operator<<(std::basic_ostream<_CharT, _Traits>& __os,
+		   const std::negative_binomial_distribution<_IntType1>& __x);
+
+      /**
+       * @brief Extracts a %negative_binomial_distribution random number
+       *        distribution @p __x from the input stream @p __is.
+       *
+       * @param __is An input stream.
+       * @param __x A %negative_binomial_distribution random number
+       *            generator engine.
+       *
+       * @returns The input stream with @p __x extracted or in an error state.
+       */
+      template<typename _IntType1, typename _CharT, typename _Traits>
+	friend std::basic_istream<_CharT, _Traits>&
+	operator>>(std::basic_istream<_CharT, _Traits>& __is,
+		   std::negative_binomial_distribution<_IntType1>& __x);
+
+    private:
+      template<typename _ForwardIterator,
+	       typename _UniformRandomNumberGenerator>
+	void
+	__generate_impl(_ForwardIterator __f, _ForwardIterator __t,
+			_UniformRandomNumberGenerator& __urng);
+      template<typename _ForwardIterator,
+	       typename _UniformRandomNumberGenerator>
+	void
+	__generate_impl(_ForwardIterator __f, _ForwardIterator __t,
+			_UniformRandomNumberGenerator& __urng,
+			const param_type& __p);
+
+      param_type _M_param;
+
+      std::gamma_distribution<double> _M_gd;
+    };
+
+  /**
+   * @brief Return true if two negative binomial distributions are different.
+   */
+  template<typename _IntType>
+    inline bool
+    operator!=(const std::negative_binomial_distribution<_IntType>& __d1,
+	       const std::negative_binomial_distribution<_IntType>& __d2)
+    { return !(__d1 == __d2); }
+
+
+  /// @} group random_distributions_bernoulli
+
+  /**
+   * @addtogroup random_distributions_poisson Poisson Distributions
+   * @ingroup random_distributions
+   * @{
+   */
+
+  /**
+   * @brief A discrete Poisson random number distribution.
+   *
+   * The formula for the Poisson probability density function is
+   * @f$p(i|\mu) = \frac{\mu^i}{i!} e^{-\mu}@f$ where @f$\mu@f$ is the
+   * parameter of the distribution.
+   */
+  template<typename _IntType = int>
+    class poisson_distribution
+    {
+      static_assert(std::is_integral<_IntType>::value,
+		    "result_type must be an integral type");
+
+    public:
+      /** The type of the range of the distribution. */
+      typedef _IntType  result_type;
+
+      /** Parameter type. */
+      struct param_type
+      {
+	typedef poisson_distribution<_IntType> distribution_type;
+	friend class poisson_distribution<_IntType>;
+
+	param_type() : param_type(1.0) { }
+
+	explicit
+	param_type(double __mean)
+	: _M_mean(__mean)
+	{
+	  __glibcxx_assert(_M_mean > 0.0);
+	  _M_initialize();
+	}
+
+	double
+	mean() const
+	{ return _M_mean; }
+
+	friend bool
+	operator==(const param_type& __p1, const param_type& __p2)
+	{ return __p1._M_mean == __p2._M_mean; }
+
+	friend bool
+	operator!=(const param_type& __p1, const param_type& __p2)
+	{ return !(__p1 == __p2); }
+
+      private:
+	// Hosts either log(mean) or the threshold of the simple method.
+	void
+	_M_initialize();
+
+	double _M_mean;
+
+	double _M_lm_thr;
+#if _GLIBCXX_USE_C99_MATH_TR1
+	double _M_lfm, _M_sm, _M_d, _M_scx, _M_1cx, _M_c2b, _M_cb;
+#endif
+      };
+
+      // constructors and member functions
+
+      poisson_distribution() : poisson_distribution(1.0) { }
+
+      explicit
+      poisson_distribution(double __mean)
+      : _M_param(__mean), _M_nd()
+      { }
+
+      explicit
+      poisson_distribution(const param_type& __p)
+      : _M_param(__p), _M_nd()
+      { }
+
+      /**
+       * @brief Resets the distribution state.
+       */
+      void
+      reset()
+      { _M_nd.reset(); }
+
+      /**
+       * @brief Returns the distribution parameter @p mean.
+       */
+      double
+      mean() const
+      { return _M_param.mean(); }
+
+      /**
+       * @brief Returns the parameter set of the distribution.
+       */
+      param_type
+      param() const
+      { return _M_param; }
+
+      /**
+       * @brief Sets the parameter set of the distribution.
+       * @param __param The new parameter set of the distribution.
+       */
+      void
+      param(const param_type& __param)
+      { _M_param = __param; }
+
+      /**
+       * @brief Returns the greatest lower bound value of the distribution.
+       */
+      result_type
+      min() const
+      { return 0; }
+
+      /**
+       * @brief Returns the least upper bound value of the distribution.
+       */
+      result_type
+      max() const
+      { return std::numeric_limits<result_type>::max(); }
+
+      /**
+       * @brief Generating functions.
+       */
+      template<typename _UniformRandomNumberGenerator>
+	result_type
+	operator()(_UniformRandomNumberGenerator& __urng)
+	{ return this->operator()(__urng, _M_param); }
+
+      template<typename _UniformRandomNumberGenerator>
+	result_type
+	operator()(_UniformRandomNumberGenerator& __urng,
+		   const param_type& __p);
+
+      template<typename _ForwardIterator,
+	       typename _UniformRandomNumberGenerator>
+	void
+	__generate(_ForwardIterator __f, _ForwardIterator __t,
+		   _UniformRandomNumberGenerator& __urng)
+	{ this->__generate(__f, __t, __urng, _M_param); }
+
+      template<typename _ForwardIterator,
+	       typename _UniformRandomNumberGenerator>
+	void
+	__generate(_ForwardIterator __f, _ForwardIterator __t,
+		   _UniformRandomNumberGenerator& __urng,
+		   const param_type& __p)
+	{ this->__generate_impl(__f, __t, __urng, __p); }
+
+      template<typename _UniformRandomNumberGenerator>
+	void
+	__generate(result_type* __f, result_type* __t,
+		   _UniformRandomNumberGenerator& __urng,
+		   const param_type& __p)
+	{ this->__generate_impl(__f, __t, __urng, __p); }
+
+       /**
+	* @brief Return true if two Poisson distributions have the same
+	*        parameters and the sequences that would be generated
+	*        are equal.
+	*/
+      friend bool
+      operator==(const poisson_distribution& __d1,
+		 const poisson_distribution& __d2)
+#ifdef _GLIBCXX_USE_C99_MATH_TR1
+      { return __d1._M_param == __d2._M_param && __d1._M_nd == __d2._M_nd; }
+#else
+      { return __d1._M_param == __d2._M_param; }
+#endif
+
+      /**
+       * @brief Inserts a %poisson_distribution random number distribution
+       * @p __x into the output stream @p __os.
+       *
+       * @param __os An output stream.
+       * @param __x  A %poisson_distribution random number distribution.
+       *
+       * @returns The output stream with the state of @p __x inserted or in
+       * an error state.
+       */
+      template<typename _IntType1, typename _CharT, typename _Traits>
+	friend std::basic_ostream<_CharT, _Traits>&
+	operator<<(std::basic_ostream<_CharT, _Traits>& __os,
+		   const std::poisson_distribution<_IntType1>& __x);
+
+      /**
+       * @brief Extracts a %poisson_distribution random number distribution
+       * @p __x from the input stream @p __is.
+       *
+       * @param __is An input stream.
+       * @param __x  A %poisson_distribution random number generator engine.
+       *
+       * @returns The input stream with @p __x extracted or in an error
+       *          state.
+       */
+      template<typename _IntType1, typename _CharT, typename _Traits>
+	friend std::basic_istream<_CharT, _Traits>&
+	operator>>(std::basic_istream<_CharT, _Traits>& __is,
+		   std::poisson_distribution<_IntType1>& __x);
+
+    private:
+      template<typename _ForwardIterator,
+	       typename _UniformRandomNumberGenerator>
+	void
+	__generate_impl(_ForwardIterator __f, _ForwardIterator __t,
+			_UniformRandomNumberGenerator& __urng,
+			const param_type& __p);
+
+      param_type _M_param;
+
+      // NB: Unused when _GLIBCXX_USE_C99_MATH_TR1 is undefined.
+      std::normal_distribution<double> _M_nd;
+    };
+
+  /**
+   * @brief Return true if two Poisson distributions are different.
+   */
+  template<typename _IntType>
+    inline bool
+    operator!=(const std::poisson_distribution<_IntType>& __d1,
+	       const std::poisson_distribution<_IntType>& __d2)
+    { return !(__d1 == __d2); }
+
+
+  /**
+   * @brief An exponential continuous distribution for random numbers.
+   *
+   * The formula for the exponential probability density function is
+   * @f$p(x|\lambda) = \lambda e^{-\lambda x}@f$.
+   *
+   * <table border=1 cellpadding=10 cellspacing=0>
+   * <caption align=top>Distribution Statistics</caption>
+   * <tr><td>Mean</td><td>@f$\frac{1}{\lambda}@f$</td></tr>
+   * <tr><td>Median</td><td>@f$\frac{\ln 2}{\lambda}@f$</td></tr>
+   * <tr><td>Mode</td><td>@f$zero@f$</td></tr>
+   * <tr><td>Range</td><td>@f$[0, \infty]@f$</td></tr>
+   * <tr><td>Standard Deviation</td><td>@f$\frac{1}{\lambda}@f$</td></tr>
+   * </table>
+   */
+  template<typename _RealType = double>
+    class exponential_distribution
+    {
+      static_assert(std::is_floating_point<_RealType>::value,
+		    "result_type must be a floating point type");
+
+    public:
+      /** The type of the range of the distribution. */
+      typedef _RealType result_type;
+
+      /** Parameter type. */
+      struct param_type
+      {
+	typedef exponential_distribution<_RealType> distribution_type;
+
+	param_type() : param_type(1.0) { }
+
+	explicit
+	param_type(_RealType __lambda)
+	: _M_lambda(__lambda)
+	{
+	  __glibcxx_assert(_M_lambda > _RealType(0));
+	}
+
+	_RealType
+	lambda() const
+	{ return _M_lambda; }
+
+	friend bool
+	operator==(const param_type& __p1, const param_type& __p2)
+	{ return __p1._M_lambda == __p2._M_lambda; }
+
+	friend bool
+	operator!=(const param_type& __p1, const param_type& __p2)
+	{ return !(__p1 == __p2); }
+
+      private:
+	_RealType _M_lambda;
+      };
+
+    public:
+      /**
+       * @brief Constructs an exponential distribution with inverse scale
+       *        parameter 1.0
+       */
+      exponential_distribution() : exponential_distribution(1.0) { }
+
+      /**
+       * @brief Constructs an exponential distribution with inverse scale
+       *        parameter @f$\lambda@f$.
+       */
+      explicit
+      exponential_distribution(_RealType __lambda)
+      : _M_param(__lambda)
+      { }
+
+      explicit
+      exponential_distribution(const param_type& __p)
+      : _M_param(__p)
+      { }
+
+      /**
+       * @brief Resets the distribution state.
+       *
+       * Has no effect on exponential distributions.
+       */
+      void
+      reset() { }
+
+      /**
+       * @brief Returns the inverse scale parameter of the distribution.
+       */
+      _RealType
+      lambda() const
+      { return _M_param.lambda(); }
+
+      /**
+       * @brief Returns the parameter set of the distribution.
+       */
+      param_type
+      param() const
+      { return _M_param; }
+
+      /**
+       * @brief Sets the parameter set of the distribution.
+       * @param __param The new parameter set of the distribution.
+       */
+      void
+      param(const param_type& __param)
+      { _M_param = __param; }
+
+      /**
+       * @brief Returns the greatest lower bound value of the distribution.
+       */
+      result_type
+      min() const
+      { return result_type(0); }
+
+      /**
+       * @brief Returns the least upper bound value of the distribution.
+       */
+      result_type
+      max() const
+      { return std::numeric_limits<result_type>::max(); }
+
+      /**
+       * @brief Generating functions.
+       */
+      template<typename _UniformRandomNumberGenerator>
+	result_type
+	operator()(_UniformRandomNumberGenerator& __urng)
+        { return this->operator()(__urng, _M_param); }
+
+      template<typename _UniformRandomNumberGenerator>
+	result_type
+	operator()(_UniformRandomNumberGenerator& __urng,
+		   const param_type& __p)
+	{
+	  __detail::_Adaptor<_UniformRandomNumberGenerator, result_type>
+	    __aurng(__urng);
+	  return -std::log(result_type(1) - __aurng()) / __p.lambda();
+	}
+
+      template<typename _ForwardIterator,
+	       typename _UniformRandomNumberGenerator>
+	void
+	__generate(_ForwardIterator __f, _ForwardIterator __t,
+		   _UniformRandomNumberGenerator& __urng)
+	{ this->__generate(__f, __t, __urng, _M_param); }
+
+      template<typename _ForwardIterator,
+	       typename _UniformRandomNumberGenerator>
+	void
+	__generate(_ForwardIterator __f, _ForwardIterator __t,
+		   _UniformRandomNumberGenerator& __urng,
+		   const param_type& __p)
+	{ this->__generate_impl(__f, __t, __urng, __p); }
+
+      template<typename _UniformRandomNumberGenerator>
+	void
+	__generate(result_type* __f, result_type* __t,
+		   _UniformRandomNumberGenerator& __urng,
+		   const param_type& __p)
+	{ this->__generate_impl(__f, __t, __urng, __p); }
+
+      /**
+       * @brief Return true if two exponential distributions have the same
+       *        parameters.
+       */
+      friend bool
+      operator==(const exponential_distribution& __d1,
+		 const exponential_distribution& __d2)
+      { return __d1._M_param == __d2._M_param; }
+
+    private:
+      template<typename _ForwardIterator,
+	       typename _UniformRandomNumberGenerator>
+	void
+	__generate_impl(_ForwardIterator __f, _ForwardIterator __t,
+			_UniformRandomNumberGenerator& __urng,
+			const param_type& __p);
+
+      param_type _M_param;
+    };
+
+  /**
+   * @brief Return true if two exponential distributions have different
+   *        parameters.
+   */
+  template<typename _RealType>
+    inline bool
+    operator!=(const std::exponential_distribution<_RealType>& __d1,
+	       const std::exponential_distribution<_RealType>& __d2)
+    { return !(__d1 == __d2); }
+
+  /**
+   * @brief Inserts a %exponential_distribution random number distribution
+   * @p __x into the output stream @p __os.
+   *
+   * @param __os An output stream.
+   * @param __x  A %exponential_distribution random number distribution.
+   *
+   * @returns The output stream with the state of @p __x inserted or in
+   * an error state.
+   */
+  template<typename _RealType, typename _CharT, typename _Traits>
+    std::basic_ostream<_CharT, _Traits>&
+    operator<<(std::basic_ostream<_CharT, _Traits>& __os,
+	       const std::exponential_distribution<_RealType>& __x);
+
+  /**
+   * @brief Extracts a %exponential_distribution random number distribution
+   * @p __x from the input stream @p __is.
+   *
+   * @param __is An input stream.
+   * @param __x A %exponential_distribution random number
+   *            generator engine.
+   *
+   * @returns The input stream with @p __x extracted or in an error state.
+   */
+  template<typename _RealType, typename _CharT, typename _Traits>
+    std::basic_istream<_CharT, _Traits>&
+    operator>>(std::basic_istream<_CharT, _Traits>& __is,
+	       std::exponential_distribution<_RealType>& __x);
+
+
+  /**
+   * @brief A weibull_distribution random number distribution.
+   *
+   * The formula for the normal probability density function is:
+   * @f[
+   *     p(x|\alpha,\beta) = \frac{\alpha}{\beta} (\frac{x}{\beta})^{\alpha-1}
+   *                         \exp{(-(\frac{x}{\beta})^\alpha)} 
+   * @f]
+   */
+  template<typename _RealType = double>
+    class weibull_distribution
+    {
+      static_assert(std::is_floating_point<_RealType>::value,
+		    "result_type must be a floating point type");
+
+    public:
+      /** The type of the range of the distribution. */
+      typedef _RealType result_type;
+
+      /** Parameter type. */
+      struct param_type
+      {
+	typedef weibull_distribution<_RealType> distribution_type;
+
+	param_type() : param_type(1.0) { }
+
+	explicit
+	param_type(_RealType __a, _RealType __b = _RealType(1.0))
+	: _M_a(__a), _M_b(__b)
+	{ }
+
+	_RealType
+	a() const
+	{ return _M_a; }
+
+	_RealType
+	b() const
+	{ return _M_b; }
+
+	friend bool
+	operator==(const param_type& __p1, const param_type& __p2)
+	{ return __p1._M_a == __p2._M_a && __p1._M_b == __p2._M_b; }
+
+	friend bool
+	operator!=(const param_type& __p1, const param_type& __p2)
+	{ return !(__p1 == __p2); }
+
+      private:
+	_RealType _M_a;
+	_RealType _M_b;
+      };
+
+      weibull_distribution() : weibull_distribution(1.0) { }
+
+      explicit
+      weibull_distribution(_RealType __a, _RealType __b = _RealType(1))
+      : _M_param(__a, __b)
+      { }
+
+      explicit
+      weibull_distribution(const param_type& __p)
+      : _M_param(__p)
+      { }
+
+      /**
+       * @brief Resets the distribution state.
+       */
+      void
+      reset()
+      { }
+
+      /**
+       * @brief Return the @f$a@f$ parameter of the distribution.
+       */
+      _RealType
+      a() const
+      { return _M_param.a(); }
+
+      /**
+       * @brief Return the @f$b@f$ parameter of the distribution.
+       */
+      _RealType
+      b() const
+      { return _M_param.b(); }
+
+      /**
+       * @brief Returns the parameter set of the distribution.
+       */
+      param_type
+      param() const
+      { return _M_param; }
+
+      /**
+       * @brief Sets the parameter set of the distribution.
+       * @param __param The new parameter set of the distribution.
+       */
+      void
+      param(const param_type& __param)
+      { _M_param = __param; }
+
+      /**
+       * @brief Returns the greatest lower bound value of the distribution.
+       */
+      result_type
+      min() const
+      { return result_type(0); }
+
+      /**
+       * @brief Returns the least upper bound value of the distribution.
+       */
+      result_type
+      max() const
+      { return std::numeric_limits<result_type>::max(); }
+
+      /**
+       * @brief Generating functions.
+       */
+      template<typename _UniformRandomNumberGenerator>
+	result_type
+	operator()(_UniformRandomNumberGenerator& __urng)
+	{ return this->operator()(__urng, _M_param); }
+
+      template<typename _UniformRandomNumberGenerator>
+	result_type
+	operator()(_UniformRandomNumberGenerator& __urng,
+		   const param_type& __p);
+
+      template<typename _ForwardIterator,
+	       typename _UniformRandomNumberGenerator>
+	void
+	__generate(_ForwardIterator __f, _ForwardIterator __t,
+		   _UniformRandomNumberGenerator& __urng)
+	{ this->__generate(__f, __t, __urng, _M_param); }
+
+      template<typename _ForwardIterator,
+	       typename _UniformRandomNumberGenerator>
+	void
+	__generate(_ForwardIterator __f, _ForwardIterator __t,
+		   _UniformRandomNumberGenerator& __urng,
+		   const param_type& __p)
+	{ this->__generate_impl(__f, __t, __urng, __p); }
+
+      template<typename _UniformRandomNumberGenerator>
+	void
+	__generate(result_type* __f, result_type* __t,
+		   _UniformRandomNumberGenerator& __urng,
+		   const param_type& __p)
+	{ this->__generate_impl(__f, __t, __urng, __p); }
+
+      /**
+       * @brief Return true if two Weibull distributions have the same
+       *        parameters.
+       */
+      friend bool
+      operator==(const weibull_distribution& __d1,
+		 const weibull_distribution& __d2)
+      { return __d1._M_param == __d2._M_param; }
+
+    private:
+      template<typename _ForwardIterator,
+	       typename _UniformRandomNumberGenerator>
+	void
+	__generate_impl(_ForwardIterator __f, _ForwardIterator __t,
+			_UniformRandomNumberGenerator& __urng,
+			const param_type& __p);
+
+      param_type _M_param;
+    };
+
+   /**
+    * @brief Return true if two Weibull distributions have different
+    *        parameters.
+    */
+  template<typename _RealType>
+    inline bool
+    operator!=(const std::weibull_distribution<_RealType>& __d1,
+	       const std::weibull_distribution<_RealType>& __d2)
+    { return !(__d1 == __d2); }
+
+  /**
+   * @brief Inserts a %weibull_distribution random number distribution
+   * @p __x into the output stream @p __os.
+   *
+   * @param __os An output stream.
+   * @param __x  A %weibull_distribution random number distribution.
+   *
+   * @returns The output stream with the state of @p __x inserted or in
+   * an error state.
+   */
+  template<typename _RealType, typename _CharT, typename _Traits>
+    std::basic_ostream<_CharT, _Traits>&
+    operator<<(std::basic_ostream<_CharT, _Traits>& __os,
+	       const std::weibull_distribution<_RealType>& __x);
+
+  /**
+   * @brief Extracts a %weibull_distribution random number distribution
+   * @p __x from the input stream @p __is.
+   *
+   * @param __is An input stream.
+   * @param __x A %weibull_distribution random number
+   *            generator engine.
+   *
+   * @returns The input stream with @p __x extracted or in an error state.
+   */
+  template<typename _RealType, typename _CharT, typename _Traits>
+    std::basic_istream<_CharT, _Traits>&
+    operator>>(std::basic_istream<_CharT, _Traits>& __is,
+	       std::weibull_distribution<_RealType>& __x);
+
+
+  /**
+   * @brief A extreme_value_distribution random number distribution.
+   *
+   * The formula for the normal probability mass function is
+   * @f[
+   *     p(x|a,b) = \frac{1}{b}
+   *                \exp( \frac{a-x}{b} - \exp(\frac{a-x}{b})) 
+   * @f]
+   */
+  template<typename _RealType = double>
+    class extreme_value_distribution
+    {
+      static_assert(std::is_floating_point<_RealType>::value,
+		    "result_type must be a floating point type");
+
+    public:
+      /** The type of the range of the distribution. */
+      typedef _RealType result_type;
+
+      /** Parameter type. */
+      struct param_type
+      {
+	typedef extreme_value_distribution<_RealType> distribution_type;
+
+	param_type() : param_type(0.0) { }
+
+	explicit
+	param_type(_RealType __a, _RealType __b = _RealType(1.0))
+	: _M_a(__a), _M_b(__b)
+	{ }
+
+	_RealType
+	a() const
+	{ return _M_a; }
+
+	_RealType
+	b() const
+	{ return _M_b; }
+
+	friend bool
+	operator==(const param_type& __p1, const param_type& __p2)
+	{ return __p1._M_a == __p2._M_a && __p1._M_b == __p2._M_b; }
+
+	friend bool
+	operator!=(const param_type& __p1, const param_type& __p2)
+	{ return !(__p1 == __p2); }
+
+      private:
+	_RealType _M_a;
+	_RealType _M_b;
+      };
+
+      extreme_value_distribution() : extreme_value_distribution(0.0) { }
+
+      explicit
+      extreme_value_distribution(_RealType __a, _RealType __b = _RealType(1))
+      : _M_param(__a, __b)
+      { }
+
+      explicit
+      extreme_value_distribution(const param_type& __p)
+      : _M_param(__p)
+      { }
+
+      /**
+       * @brief Resets the distribution state.
+       */
+      void
+      reset()
+      { }
+
+      /**
+       * @brief Return the @f$a@f$ parameter of the distribution.
+       */
+      _RealType
+      a() const
+      { return _M_param.a(); }
+
+      /**
+       * @brief Return the @f$b@f$ parameter of the distribution.
+       */
+      _RealType
+      b() const
+      { return _M_param.b(); }
+
+      /**
+       * @brief Returns the parameter set of the distribution.
+       */
+      param_type
+      param() const
+      { return _M_param; }
+
+      /**
+       * @brief Sets the parameter set of the distribution.
+       * @param __param The new parameter set of the distribution.
+       */
+      void
+      param(const param_type& __param)
+      { _M_param = __param; }
+
+      /**
+       * @brief Returns the greatest lower bound value of the distribution.
+       */
+      result_type
+      min() const
+      { return std::numeric_limits<result_type>::lowest(); }
+
+      /**
+       * @brief Returns the least upper bound value of the distribution.
+       */
+      result_type
+      max() const
+      { return std::numeric_limits<result_type>::max(); }
+
+      /**
+       * @brief Generating functions.
+       */
+      template<typename _UniformRandomNumberGenerator>
+	result_type
+	operator()(_UniformRandomNumberGenerator& __urng)
+	{ return this->operator()(__urng, _M_param); }
+
+      template<typename _UniformRandomNumberGenerator>
+	result_type
+	operator()(_UniformRandomNumberGenerator& __urng,
+		   const param_type& __p);
+
+      template<typename _ForwardIterator,
+	       typename _UniformRandomNumberGenerator>
+	void
+	__generate(_ForwardIterator __f, _ForwardIterator __t,
+		   _UniformRandomNumberGenerator& __urng)
+	{ this->__generate(__f, __t, __urng, _M_param); }
+
+      template<typename _ForwardIterator,
+	       typename _UniformRandomNumberGenerator>
+	void
+	__generate(_ForwardIterator __f, _ForwardIterator __t,
+		   _UniformRandomNumberGenerator& __urng,
+		   const param_type& __p)
+	{ this->__generate_impl(__f, __t, __urng, __p); }
+
+      template<typename _UniformRandomNumberGenerator>
+	void
+	__generate(result_type* __f, result_type* __t,
+		   _UniformRandomNumberGenerator& __urng,
+		   const param_type& __p)
+	{ this->__generate_impl(__f, __t, __urng, __p); }
+
+      /**
+       * @brief Return true if two extreme value distributions have the same
+       *        parameters.
+       */
+      friend bool
+      operator==(const extreme_value_distribution& __d1,
+		 const extreme_value_distribution& __d2)
+      { return __d1._M_param == __d2._M_param; }
+
+    private:
+      template<typename _ForwardIterator,
+	       typename _UniformRandomNumberGenerator>
+	void
+	__generate_impl(_ForwardIterator __f, _ForwardIterator __t,
+			_UniformRandomNumberGenerator& __urng,
+			const param_type& __p);
+
+      param_type _M_param;
+    };
+
+  /**
+    * @brief Return true if two extreme value distributions have different
+    *        parameters.
+   */
+  template<typename _RealType>
+    inline bool
+    operator!=(const std::extreme_value_distribution<_RealType>& __d1,
+	       const std::extreme_value_distribution<_RealType>& __d2)
+    { return !(__d1 == __d2); }
+
+  /**
+   * @brief Inserts a %extreme_value_distribution random number distribution
+   * @p __x into the output stream @p __os.
+   *
+   * @param __os An output stream.
+   * @param __x  A %extreme_value_distribution random number distribution.
+   *
+   * @returns The output stream with the state of @p __x inserted or in
+   * an error state.
+   */
+  template<typename _RealType, typename _CharT, typename _Traits>
+    std::basic_ostream<_CharT, _Traits>&
+    operator<<(std::basic_ostream<_CharT, _Traits>& __os,
+	       const std::extreme_value_distribution<_RealType>& __x);
+
+  /**
+   * @brief Extracts a %extreme_value_distribution random number
+   *        distribution @p __x from the input stream @p __is.
+   *
+   * @param __is An input stream.
+   * @param __x A %extreme_value_distribution random number
+   *            generator engine.
+   *
+   * @returns The input stream with @p __x extracted or in an error state.
+   */
+  template<typename _RealType, typename _CharT, typename _Traits>
+    std::basic_istream<_CharT, _Traits>&
+    operator>>(std::basic_istream<_CharT, _Traits>& __is,
+	       std::extreme_value_distribution<_RealType>& __x);
+
+
+  /**
+   * @brief A discrete_distribution random number distribution.
+   *
+   * The formula for the discrete probability mass function is
+   *
+   */
+  template<typename _IntType = int>
+    class discrete_distribution
+    {
+      static_assert(std::is_integral<_IntType>::value,
+		    "result_type must be an integral type");
+
+    public:
+      /** The type of the range of the distribution. */
+      typedef _IntType result_type;
+
+      /** Parameter type. */
+      struct param_type
+      {
+	typedef discrete_distribution<_IntType> distribution_type;
+	friend class discrete_distribution<_IntType>;
+
+	param_type()
+	: _M_prob(), _M_cp()
+	{ }
+
+	template<typename _InputIterator>
+	  param_type(_InputIterator __wbegin,
+		     _InputIterator __wend)
+	  : _M_prob(__wbegin, __wend), _M_cp()
+	  { _M_initialize(); }
+
+	param_type(initializer_list<double> __wil)
+	: _M_prob(__wil.begin(), __wil.end()), _M_cp()
+	{ _M_initialize(); }
+
+	template<typename _Func>
+	  param_type(size_t __nw, double __xmin, double __xmax,
+		     _Func __fw);
+
+	// See: http://cpp-next.com/archive/2010/10/implicit-move-must-go/
+	param_type(const param_type&) = default;
+	param_type& operator=(const param_type&) = default;
+
+	std::vector<double>
+	probabilities() const
+	{ return _M_prob.empty() ? std::vector<double>(1, 1.0) : _M_prob; }
+
+	friend bool
+	operator==(const param_type& __p1, const param_type& __p2)
+	{ return __p1._M_prob == __p2._M_prob; }
+
+	friend bool
+	operator!=(const param_type& __p1, const param_type& __p2)
+	{ return !(__p1 == __p2); }
+
+      private:
+	void
+	_M_initialize();
+
+	std::vector<double> _M_prob;
+	std::vector<double> _M_cp;
+      };
+
+      discrete_distribution()
+      : _M_param()
+      { }
+
+      template<typename _InputIterator>
+	discrete_distribution(_InputIterator __wbegin,
+			      _InputIterator __wend)
+	: _M_param(__wbegin, __wend)
+	{ }
+
+      discrete_distribution(initializer_list<double> __wl)
+      : _M_param(__wl)
+      { }
+
+      template<typename _Func>
+	discrete_distribution(size_t __nw, double __xmin, double __xmax,
+			      _Func __fw)
+	: _M_param(__nw, __xmin, __xmax, __fw)
+	{ }
+
+      explicit
+      discrete_distribution(const param_type& __p)
+      : _M_param(__p)
+      { }
+
+      /**
+       * @brief Resets the distribution state.
+       */
+      void
+      reset()
+      { }
+
+      /**
+       * @brief Returns the probabilities of the distribution.
+       */
+      std::vector<double>
+      probabilities() const
+      {
+	return _M_param._M_prob.empty()
+	  ? std::vector<double>(1, 1.0) : _M_param._M_prob;
+      }
+
+      /**
+       * @brief Returns the parameter set of the distribution.
+       */
+      param_type
+      param() const
+      { return _M_param; }
+
+      /**
+       * @brief Sets the parameter set of the distribution.
+       * @param __param The new parameter set of the distribution.
+       */
+      void
+      param(const param_type& __param)
+      { _M_param = __param; }
+
+      /**
+       * @brief Returns the greatest lower bound value of the distribution.
+       */
+      result_type
+      min() const
+      { return result_type(0); }
+
+      /**
+       * @brief Returns the least upper bound value of the distribution.
+       */
+      result_type
+      max() const
+      {
+	return _M_param._M_prob.empty()
+	  ? result_type(0) : result_type(_M_param._M_prob.size() - 1);
+      }
+
+      /**
+       * @brief Generating functions.
+       */
+      template<typename _UniformRandomNumberGenerator>
+	result_type
+	operator()(_UniformRandomNumberGenerator& __urng)
+	{ return this->operator()(__urng, _M_param); }
+
+      template<typename _UniformRandomNumberGenerator>
+	result_type
+	operator()(_UniformRandomNumberGenerator& __urng,
+		   const param_type& __p);
+
+      template<typename _ForwardIterator,
+	       typename _UniformRandomNumberGenerator>
+	void
+	__generate(_ForwardIterator __f, _ForwardIterator __t,
+		   _UniformRandomNumberGenerator& __urng)
+	{ this->__generate(__f, __t, __urng, _M_param); }
+
+      template<typename _ForwardIterator,
+	       typename _UniformRandomNumberGenerator>
+	void
+	__generate(_ForwardIterator __f, _ForwardIterator __t,
+		   _UniformRandomNumberGenerator& __urng,
+		   const param_type& __p)
+	{ this->__generate_impl(__f, __t, __urng, __p); }
+
+      template<typename _UniformRandomNumberGenerator>
+	void
+	__generate(result_type* __f, result_type* __t,
+		   _UniformRandomNumberGenerator& __urng,
+		   const param_type& __p)
+	{ this->__generate_impl(__f, __t, __urng, __p); }
+
+      /**
+       * @brief Return true if two discrete distributions have the same
+       *        parameters.
+       */
+      friend bool
+      operator==(const discrete_distribution& __d1,
+		 const discrete_distribution& __d2)
+      { return __d1._M_param == __d2._M_param; }
+
+      /**
+       * @brief Inserts a %discrete_distribution random number distribution
+       * @p __x into the output stream @p __os.
+       *
+       * @param __os An output stream.
+       * @param __x  A %discrete_distribution random number distribution.
+       *
+       * @returns The output stream with the state of @p __x inserted or in
+       * an error state.
+       */
+      template<typename _IntType1, typename _CharT, typename _Traits>
+	friend std::basic_ostream<_CharT, _Traits>&
+	operator<<(std::basic_ostream<_CharT, _Traits>& __os,
+		   const std::discrete_distribution<_IntType1>& __x);
+
+      /**
+       * @brief Extracts a %discrete_distribution random number distribution
+       * @p __x from the input stream @p __is.
+       *
+       * @param __is An input stream.
+       * @param __x A %discrete_distribution random number
+       *            generator engine.
+       *
+       * @returns The input stream with @p __x extracted or in an error
+       *          state.
+       */
+      template<typename _IntType1, typename _CharT, typename _Traits>
+	friend std::basic_istream<_CharT, _Traits>&
+	operator>>(std::basic_istream<_CharT, _Traits>& __is,
+		   std::discrete_distribution<_IntType1>& __x);
+
+    private:
+      template<typename _ForwardIterator,
+	       typename _UniformRandomNumberGenerator>
+	void
+	__generate_impl(_ForwardIterator __f, _ForwardIterator __t,
+			_UniformRandomNumberGenerator& __urng,
+			const param_type& __p);
+
+      param_type _M_param;
+    };
+
+  /**
+    * @brief Return true if two discrete distributions have different
+    *        parameters.
+    */
+  template<typename _IntType>
+    inline bool
+    operator!=(const std::discrete_distribution<_IntType>& __d1,
+	       const std::discrete_distribution<_IntType>& __d2)
+    { return !(__d1 == __d2); }
+
+
+  /**
+   * @brief A piecewise_constant_distribution random number distribution.
+   *
+   * The formula for the piecewise constant probability mass function is
+   *
+   */
+  template<typename _RealType = double>
+    class piecewise_constant_distribution
+    {
+      static_assert(std::is_floating_point<_RealType>::value,
+		    "result_type must be a floating point type");
+
+    public:
+      /** The type of the range of the distribution. */
+      typedef _RealType result_type;
+
+      /** Parameter type. */
+      struct param_type
+      {
+	typedef piecewise_constant_distribution<_RealType> distribution_type;
+	friend class piecewise_constant_distribution<_RealType>;
+
+	param_type()
+	: _M_int(), _M_den(), _M_cp()
+	{ }
+
+	template<typename _InputIteratorB, typename _InputIteratorW>
+	  param_type(_InputIteratorB __bfirst,
+		     _InputIteratorB __bend,
+		     _InputIteratorW __wbegin);
+
+	template<typename _Func>
+	  param_type(initializer_list<_RealType> __bi, _Func __fw);
+
+	template<typename _Func>
+	  param_type(size_t __nw, _RealType __xmin, _RealType __xmax,
+		     _Func __fw);
+
+	// See: http://cpp-next.com/archive/2010/10/implicit-move-must-go/
+	param_type(const param_type&) = default;
+	param_type& operator=(const param_type&) = default;
+
+	std::vector<_RealType>
+	intervals() const
+	{
+	  if (_M_int.empty())
+	    {
+	      std::vector<_RealType> __tmp(2);
+	      __tmp[1] = _RealType(1);
+	      return __tmp;
+	    }
+	  else
+	    return _M_int;
+	}
+
+	std::vector<double>
+	densities() const
+	{ return _M_den.empty() ? std::vector<double>(1, 1.0) : _M_den; }
+
+	friend bool
+	operator==(const param_type& __p1, const param_type& __p2)
+	{ return __p1._M_int == __p2._M_int && __p1._M_den == __p2._M_den; }
+
+	friend bool
+	operator!=(const param_type& __p1, const param_type& __p2)
+	{ return !(__p1 == __p2); }
+
+      private:
+	void
+	_M_initialize();
+
+	std::vector<_RealType> _M_int;
+	std::vector<double> _M_den;
+	std::vector<double> _M_cp;
+      };
+
+      piecewise_constant_distribution()
+      : _M_param()
+      { }
+
+      template<typename _InputIteratorB, typename _InputIteratorW>
+	piecewise_constant_distribution(_InputIteratorB __bfirst,
+					_InputIteratorB __bend,
+					_InputIteratorW __wbegin)
+	: _M_param(__bfirst, __bend, __wbegin)
+	{ }
+
+      template<typename _Func>
+	piecewise_constant_distribution(initializer_list<_RealType> __bl,
+					_Func __fw)
+	: _M_param(__bl, __fw)
+	{ }
+
+      template<typename _Func>
+	piecewise_constant_distribution(size_t __nw,
+					_RealType __xmin, _RealType __xmax,
+					_Func __fw)
+	: _M_param(__nw, __xmin, __xmax, __fw)
+	{ }
+
+      explicit
+      piecewise_constant_distribution(const param_type& __p)
+      : _M_param(__p)
+      { }
+
+      /**
+       * @brief Resets the distribution state.
+       */
+      void
+      reset()
+      { }
+
+      /**
+       * @brief Returns a vector of the intervals.
+       */
+      std::vector<_RealType>
+      intervals() const
+      {
+	if (_M_param._M_int.empty())
+	  {
+	    std::vector<_RealType> __tmp(2);
+	    __tmp[1] = _RealType(1);
+	    return __tmp;
+	  }
+	else
+	  return _M_param._M_int;
+      }
+
+      /**
+       * @brief Returns a vector of the probability densities.
+       */
+      std::vector<double>
+      densities() const
+      {
+	return _M_param._M_den.empty()
+	  ? std::vector<double>(1, 1.0) : _M_param._M_den;
+      }
+
+      /**
+       * @brief Returns the parameter set of the distribution.
+       */
+      param_type
+      param() const
+      { return _M_param; }
+
+      /**
+       * @brief Sets the parameter set of the distribution.
+       * @param __param The new parameter set of the distribution.
+       */
+      void
+      param(const param_type& __param)
+      { _M_param = __param; }
+
+      /**
+       * @brief Returns the greatest lower bound value of the distribution.
+       */
+      result_type
+      min() const
+      {
+	return _M_param._M_int.empty()
+	  ? result_type(0) : _M_param._M_int.front();
+      }
+
+      /**
+       * @brief Returns the least upper bound value of the distribution.
+       */
+      result_type
+      max() const
+      {
+	return _M_param._M_int.empty()
+	  ? result_type(1) : _M_param._M_int.back();
+      }
+
+      /**
+       * @brief Generating functions.
+       */
+      template<typename _UniformRandomNumberGenerator>
+	result_type
+	operator()(_UniformRandomNumberGenerator& __urng)
+	{ return this->operator()(__urng, _M_param); }
+
+      template<typename _UniformRandomNumberGenerator>
+	result_type
+	operator()(_UniformRandomNumberGenerator& __urng,
+		   const param_type& __p);
+
+      template<typename _ForwardIterator,
+	       typename _UniformRandomNumberGenerator>
+	void
+	__generate(_ForwardIterator __f, _ForwardIterator __t,
+		   _UniformRandomNumberGenerator& __urng)
+	{ this->__generate(__f, __t, __urng, _M_param); }
+
+      template<typename _ForwardIterator,
+	       typename _UniformRandomNumberGenerator>
+	void
+	__generate(_ForwardIterator __f, _ForwardIterator __t,
+		   _UniformRandomNumberGenerator& __urng,
+		   const param_type& __p)
+	{ this->__generate_impl(__f, __t, __urng, __p); }
+
+      template<typename _UniformRandomNumberGenerator>
+	void
+	__generate(result_type* __f, result_type* __t,
+		   _UniformRandomNumberGenerator& __urng,
+		   const param_type& __p)
+	{ this->__generate_impl(__f, __t, __urng, __p); }
+
+      /**
+       * @brief Return true if two piecewise constant distributions have the
+       *        same parameters.
+       */
+      friend bool
+      operator==(const piecewise_constant_distribution& __d1,
+		 const piecewise_constant_distribution& __d2)
+      { return __d1._M_param == __d2._M_param; }
+
+      /**
+       * @brief Inserts a %piecewise_constant_distribution random
+       *        number distribution @p __x into the output stream @p __os.
+       *
+       * @param __os An output stream.
+       * @param __x  A %piecewise_constant_distribution random number
+       *             distribution.
+       *
+       * @returns The output stream with the state of @p __x inserted or in
+       * an error state.
+       */
+      template<typename _RealType1, typename _CharT, typename _Traits>
+	friend std::basic_ostream<_CharT, _Traits>&
+	operator<<(std::basic_ostream<_CharT, _Traits>& __os,
+		   const std::piecewise_constant_distribution<_RealType1>& __x);
+
+      /**
+       * @brief Extracts a %piecewise_constant_distribution random
+       *        number distribution @p __x from the input stream @p __is.
+       *
+       * @param __is An input stream.
+       * @param __x A %piecewise_constant_distribution random number
+       *            generator engine.
+       *
+       * @returns The input stream with @p __x extracted or in an error
+       *          state.
+       */
+      template<typename _RealType1, typename _CharT, typename _Traits>
+	friend std::basic_istream<_CharT, _Traits>&
+	operator>>(std::basic_istream<_CharT, _Traits>& __is,
+		   std::piecewise_constant_distribution<_RealType1>& __x);
+
+    private:
+      template<typename _ForwardIterator,
+	       typename _UniformRandomNumberGenerator>
+	void
+	__generate_impl(_ForwardIterator __f, _ForwardIterator __t,
+			_UniformRandomNumberGenerator& __urng,
+			const param_type& __p);
+
+      param_type _M_param;
+    };
+
+  /**
+    * @brief Return true if two piecewise constant distributions have 
+    *        different parameters.
+   */
+  template<typename _RealType>
+    inline bool
+    operator!=(const std::piecewise_constant_distribution<_RealType>& __d1,
+	       const std::piecewise_constant_distribution<_RealType>& __d2)
+    { return !(__d1 == __d2); }
+
+
+  /**
+   * @brief A piecewise_linear_distribution random number distribution.
+   *
+   * The formula for the piecewise linear probability mass function is
+   *
+   */
+  template<typename _RealType = double>
+    class piecewise_linear_distribution
+    {
+      static_assert(std::is_floating_point<_RealType>::value,
+		    "result_type must be a floating point type");
+
+    public:
+      /** The type of the range of the distribution. */
+      typedef _RealType result_type;
+
+      /** Parameter type. */
+      struct param_type
+      {
+	typedef piecewise_linear_distribution<_RealType> distribution_type;
+	friend class piecewise_linear_distribution<_RealType>;
+
+	param_type()
+	: _M_int(), _M_den(), _M_cp(), _M_m()
+	{ }
+
+	template<typename _InputIteratorB, typename _InputIteratorW>
+	  param_type(_InputIteratorB __bfirst,
+		     _InputIteratorB __bend,
+		     _InputIteratorW __wbegin);
+
+	template<typename _Func>
+	  param_type(initializer_list<_RealType> __bl, _Func __fw);
+
+	template<typename _Func>
+	  param_type(size_t __nw, _RealType __xmin, _RealType __xmax,
+		     _Func __fw);
+
+	// See: http://cpp-next.com/archive/2010/10/implicit-move-must-go/
+	param_type(const param_type&) = default;
+	param_type& operator=(const param_type&) = default;
+
+	std::vector<_RealType>
+	intervals() const
+	{
+	  if (_M_int.empty())
+	    {
+	      std::vector<_RealType> __tmp(2);
+	      __tmp[1] = _RealType(1);
+	      return __tmp;
+	    }
+	  else
+	    return _M_int;
+	}
+
+	std::vector<double>
+	densities() const
+	{ return _M_den.empty() ? std::vector<double>(2, 1.0) : _M_den; }
+
+	friend bool
+	operator==(const param_type& __p1, const param_type& __p2)
+	{ return __p1._M_int == __p2._M_int && __p1._M_den == __p2._M_den; }
+
+	friend bool
+	operator!=(const param_type& __p1, const param_type& __p2)
+	{ return !(__p1 == __p2); }
+
+      private:
+	void
+	_M_initialize();
+
+	std::vector<_RealType> _M_int;
+	std::vector<double> _M_den;
+	std::vector<double> _M_cp;
+	std::vector<double> _M_m;
+      };
+
+      piecewise_linear_distribution()
+      : _M_param()
+      { }
+
+      template<typename _InputIteratorB, typename _InputIteratorW>
+	piecewise_linear_distribution(_InputIteratorB __bfirst,
+				      _InputIteratorB __bend,
+				      _InputIteratorW __wbegin)
+	: _M_param(__bfirst, __bend, __wbegin)
+	{ }
+
+      template<typename _Func>
+	piecewise_linear_distribution(initializer_list<_RealType> __bl,
+				      _Func __fw)
+	: _M_param(__bl, __fw)
+	{ }
+
+      template<typename _Func>
+	piecewise_linear_distribution(size_t __nw,
+				      _RealType __xmin, _RealType __xmax,
+				      _Func __fw)
+	: _M_param(__nw, __xmin, __xmax, __fw)
+	{ }
+
+      explicit
+      piecewise_linear_distribution(const param_type& __p)
+      : _M_param(__p)
+      { }
+
+      /**
+       * Resets the distribution state.
+       */
+      void
+      reset()
+      { }
+
+      /**
+       * @brief Return the intervals of the distribution.
+       */
+      std::vector<_RealType>
+      intervals() const
+      {
+	if (_M_param._M_int.empty())
+	  {
+	    std::vector<_RealType> __tmp(2);
+	    __tmp[1] = _RealType(1);
+	    return __tmp;
+	  }
+	else
+	  return _M_param._M_int;
+      }
+
+      /**
+       * @brief Return a vector of the probability densities of the
+       *        distribution.
+       */
+      std::vector<double>
+      densities() const
+      {
+	return _M_param._M_den.empty()
+	  ? std::vector<double>(2, 1.0) : _M_param._M_den;
+      }
+
+      /**
+       * @brief Returns the parameter set of the distribution.
+       */
+      param_type
+      param() const
+      { return _M_param; }
+
+      /**
+       * @brief Sets the parameter set of the distribution.
+       * @param __param The new parameter set of the distribution.
+       */
+      void
+      param(const param_type& __param)
+      { _M_param = __param; }
+
+      /**
+       * @brief Returns the greatest lower bound value of the distribution.
+       */
+      result_type
+      min() const
+      {
+	return _M_param._M_int.empty()
+	  ? result_type(0) : _M_param._M_int.front();
+      }
+
+      /**
+       * @brief Returns the least upper bound value of the distribution.
+       */
+      result_type
+      max() const
+      {
+	return _M_param._M_int.empty()
+	  ? result_type(1) : _M_param._M_int.back();
+      }
+
+      /**
+       * @brief Generating functions.
+       */
+      template<typename _UniformRandomNumberGenerator>
+	result_type
+	operator()(_UniformRandomNumberGenerator& __urng)
+	{ return this->operator()(__urng, _M_param); }
+
+      template<typename _UniformRandomNumberGenerator>
+	result_type
+	operator()(_UniformRandomNumberGenerator& __urng,
+		   const param_type& __p);
+
+      template<typename _ForwardIterator,
+	       typename _UniformRandomNumberGenerator>
+	void
+	__generate(_ForwardIterator __f, _ForwardIterator __t,
+		   _UniformRandomNumberGenerator& __urng)
+	{ this->__generate(__f, __t, __urng, _M_param); }
+
+      template<typename _ForwardIterator,
+	       typename _UniformRandomNumberGenerator>
+	void
+	__generate(_ForwardIterator __f, _ForwardIterator __t,
+		   _UniformRandomNumberGenerator& __urng,
+		   const param_type& __p)
+	{ this->__generate_impl(__f, __t, __urng, __p); }
+
+      template<typename _UniformRandomNumberGenerator>
+	void
+	__generate(result_type* __f, result_type* __t,
+		   _UniformRandomNumberGenerator& __urng,
+		   const param_type& __p)
+	{ this->__generate_impl(__f, __t, __urng, __p); }
+
+      /**
+       * @brief Return true if two piecewise linear distributions have the
+       *        same parameters.
+       */
+      friend bool
+      operator==(const piecewise_linear_distribution& __d1,
+		 const piecewise_linear_distribution& __d2)
+      { return __d1._M_param == __d2._M_param; }
+
+      /**
+       * @brief Inserts a %piecewise_linear_distribution random number
+       *        distribution @p __x into the output stream @p __os.
+       *
+       * @param __os An output stream.
+       * @param __x  A %piecewise_linear_distribution random number
+       *             distribution.
+       *
+       * @returns The output stream with the state of @p __x inserted or in
+       *          an error state.
+       */
+      template<typename _RealType1, typename _CharT, typename _Traits>
+	friend std::basic_ostream<_CharT, _Traits>&
+	operator<<(std::basic_ostream<_CharT, _Traits>& __os,
+		   const std::piecewise_linear_distribution<_RealType1>& __x);
+
+      /**
+       * @brief Extracts a %piecewise_linear_distribution random number
+       *        distribution @p __x from the input stream @p __is.
+       *
+       * @param __is An input stream.
+       * @param __x  A %piecewise_linear_distribution random number
+       *             generator engine.
+       *
+       * @returns The input stream with @p __x extracted or in an error
+       *          state.
+       */
+      template<typename _RealType1, typename _CharT, typename _Traits>
+	friend std::basic_istream<_CharT, _Traits>&
+	operator>>(std::basic_istream<_CharT, _Traits>& __is,
+		   std::piecewise_linear_distribution<_RealType1>& __x);
+
+    private:
+      template<typename _ForwardIterator,
+	       typename _UniformRandomNumberGenerator>
+	void
+	__generate_impl(_ForwardIterator __f, _ForwardIterator __t,
+			_UniformRandomNumberGenerator& __urng,
+			const param_type& __p);
+
+      param_type _M_param;
+    };
+
+  /**
+    * @brief Return true if two piecewise linear distributions have
+    *        different parameters.
+   */
+  template<typename _RealType>
+    inline bool
+    operator!=(const std::piecewise_linear_distribution<_RealType>& __d1,
+	       const std::piecewise_linear_distribution<_RealType>& __d2)
+    { return !(__d1 == __d2); }
+
+
+  /// @} group random_distributions_poisson
+
+  /// @} *group random_distributions
+
+  /**
+   * @addtogroup random_utilities Random Number Utilities
+   * @ingroup random
+   * @{
+   */
+
+  /**
+   * @brief The seed_seq class generates sequences of seeds for random
+   *        number generators.
+   */
+  class seed_seq
+  {
+  public:
+    /** The type of the seed vales. */
+    typedef uint_least32_t result_type;
+
+    /** Default constructor. */
+    seed_seq() noexcept
+    : _M_v()
+    { }
+
+    template<typename _IntType, typename = _Require<is_integral<_IntType>>>
+      seed_seq(std::initializer_list<_IntType> __il);
+
+    template<typename _InputIterator>
+      seed_seq(_InputIterator __begin, _InputIterator __end);
+
+    // generating functions
+    template<typename _RandomAccessIterator>
+      void
+      generate(_RandomAccessIterator __begin, _RandomAccessIterator __end);
+
+    // property functions
+    size_t size() const noexcept
+    { return _M_v.size(); }
+
+    template<typename _OutputIterator>
+      void
+      param(_OutputIterator __dest) const
+      { std::copy(_M_v.begin(), _M_v.end(), __dest); }
+
+    // no copy functions
+    seed_seq(const seed_seq&) = delete;
+    seed_seq& operator=(const seed_seq&) = delete;
+
+  private:
+    std::vector<result_type> _M_v;
+  };
+
+  /// @} group random_utilities
+
+  /// @} group random
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@random.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@random.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@random.tcc b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@random.tcc
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@random.tcc
@@ -0,0 +1,3391 @@
+// random number generation (out of line) -*- C++ -*-
+
+// Copyright (C) 2009-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/random.tcc
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{random}
+ */
+
+#ifndef _RANDOM_TCC
+#define _RANDOM_TCC 1
+
+#include <numeric> // std::accumulate and std::partial_sum
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /// @cond undocumented
+  // (Further) implementation-space details.
+  namespace __detail
+  {
+    // General case for x = (ax + c) mod m -- use Schrage's algorithm
+    // to avoid integer overflow.
+    //
+    // Preconditions:  a > 0, m > 0.
+    //
+    // Note: only works correctly for __m % __a < __m / __a.
+    template<typename _Tp, _Tp __m, _Tp __a, _Tp __c>
+      _Tp
+      _Mod<_Tp, __m, __a, __c, false, true>::
+      __calc(_Tp __x)
+      {
+	if (__a == 1)
+	  __x %= __m;
+	else
+	  {
+	    static const _Tp __q = __m / __a;
+	    static const _Tp __r = __m % __a;
+
+	    _Tp __t1 = __a * (__x % __q);
+	    _Tp __t2 = __r * (__x / __q);
+	    if (__t1 >= __t2)
+	      __x = __t1 - __t2;
+	    else
+	      __x = __m - __t2 + __t1;
+	  }
+
+	if (__c != 0)
+	  {
+	    const _Tp __d = __m - __x;
+	    if (__d > __c)
+	      __x += __c;
+	    else
+	      __x = __c - __d;
+	  }
+	return __x;
+      }
+
+    template<typename _InputIterator, typename _OutputIterator,
+	     typename _Tp>
+      _OutputIterator
+      __normalize(_InputIterator __first, _InputIterator __last,
+		  _OutputIterator __result, const _Tp& __factor)
+      {
+	for (; __first != __last; ++__first, ++__result)
+	  *__result = *__first / __factor;
+	return __result;
+      }
+
+  } // namespace __detail
+  /// @endcond
+
+#if ! __cpp_inline_variables
+  template<typename _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
+    constexpr _UIntType
+    linear_congruential_engine<_UIntType, __a, __c, __m>::multiplier;
+
+  template<typename _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
+    constexpr _UIntType
+    linear_congruential_engine<_UIntType, __a, __c, __m>::increment;
+
+  template<typename _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
+    constexpr _UIntType
+    linear_congruential_engine<_UIntType, __a, __c, __m>::modulus;
+
+  template<typename _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
+    constexpr _UIntType
+    linear_congruential_engine<_UIntType, __a, __c, __m>::default_seed;
+#endif
+
+  /**
+   * Seeds the LCR with integral value @p __s, adjusted so that the
+   * ring identity is never a member of the convergence set.
+   */
+  template<typename _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
+    void
+    linear_congruential_engine<_UIntType, __a, __c, __m>::
+    seed(result_type __s)
+    {
+      if ((__detail::__mod<_UIntType, __m>(__c) == 0)
+	  && (__detail::__mod<_UIntType, __m>(__s) == 0))
+	_M_x = 1;
+      else
+	_M_x = __detail::__mod<_UIntType, __m>(__s);
+    }
+
+  /**
+   * Seeds the LCR engine with a value generated by @p __q.
+   */
+  template<typename _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
+    template<typename _Sseq>
+      auto
+      linear_congruential_engine<_UIntType, __a, __c, __m>::
+      seed(_Sseq& __q)
+      -> _If_seed_seq<_Sseq>
+      {
+	const _UIntType __k0 = __m == 0 ? std::numeric_limits<_UIntType>::digits
+	                                : std::__lg(__m);
+	const _UIntType __k = (__k0 + 31) / 32;
+	uint_least32_t __arr[__k + 3];
+	__q.generate(__arr + 0, __arr + __k + 3);
+	_UIntType __factor = 1u;
+	_UIntType __sum = 0u;
+	for (size_t __j = 0; __j < __k; ++__j)
+	  {
+	    __sum += __arr[__j + 3] * __factor;
+	    __factor *= __detail::_Shift<_UIntType, 32>::__value;
+	  }
+	seed(__sum);
+      }
+
+  template<typename _UIntType, _UIntType __a, _UIntType __c, _UIntType __m,
+	   typename _CharT, typename _Traits>
+    std::basic_ostream<_CharT, _Traits>&
+    operator<<(std::basic_ostream<_CharT, _Traits>& __os,
+	       const linear_congruential_engine<_UIntType,
+						__a, __c, __m>& __lcr)
+    {
+      using __ios_base = typename basic_ostream<_CharT, _Traits>::ios_base;
+
+      const typename __ios_base::fmtflags __flags = __os.flags();
+      const _CharT __fill = __os.fill();
+      __os.flags(__ios_base::dec | __ios_base::fixed | __ios_base::left);
+      __os.fill(__os.widen(' '));
+
+      __os << __lcr._M_x;
+
+      __os.flags(__flags);
+      __os.fill(__fill);
+      return __os;
+    }
+
+  template<typename _UIntType, _UIntType __a, _UIntType __c, _UIntType __m,
+	   typename _CharT, typename _Traits>
+    std::basic_istream<_CharT, _Traits>&
+    operator>>(std::basic_istream<_CharT, _Traits>& __is,
+	       linear_congruential_engine<_UIntType, __a, __c, __m>& __lcr)
+    {
+      using __ios_base = typename basic_istream<_CharT, _Traits>::ios_base;
+
+      const typename __ios_base::fmtflags __flags = __is.flags();
+      __is.flags(__ios_base::dec);
+
+      __is >> __lcr._M_x;
+
+      __is.flags(__flags);
+      return __is;
+    }
+
+#if ! __cpp_inline_variables
+  template<typename _UIntType,
+	   size_t __w, size_t __n, size_t __m, size_t __r,
+	   _UIntType __a, size_t __u, _UIntType __d, size_t __s,
+	   _UIntType __b, size_t __t, _UIntType __c, size_t __l,
+	   _UIntType __f>
+    constexpr size_t
+    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d,
+			    __s, __b, __t, __c, __l, __f>::word_size;
+
+  template<typename _UIntType,
+	   size_t __w, size_t __n, size_t __m, size_t __r,
+	   _UIntType __a, size_t __u, _UIntType __d, size_t __s,
+	   _UIntType __b, size_t __t, _UIntType __c, size_t __l,
+	   _UIntType __f>
+    constexpr size_t
+    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d,
+			    __s, __b, __t, __c, __l, __f>::state_size;
+
+  template<typename _UIntType,
+	   size_t __w, size_t __n, size_t __m, size_t __r,
+	   _UIntType __a, size_t __u, _UIntType __d, size_t __s,
+	   _UIntType __b, size_t __t, _UIntType __c, size_t __l,
+	   _UIntType __f>
+    constexpr size_t
+    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d,
+			    __s, __b, __t, __c, __l, __f>::shift_size;
+
+  template<typename _UIntType,
+	   size_t __w, size_t __n, size_t __m, size_t __r,
+	   _UIntType __a, size_t __u, _UIntType __d, size_t __s,
+	   _UIntType __b, size_t __t, _UIntType __c, size_t __l,
+	   _UIntType __f>
+    constexpr size_t
+    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d,
+			    __s, __b, __t, __c, __l, __f>::mask_bits;
+
+  template<typename _UIntType,
+	   size_t __w, size_t __n, size_t __m, size_t __r,
+	   _UIntType __a, size_t __u, _UIntType __d, size_t __s,
+	   _UIntType __b, size_t __t, _UIntType __c, size_t __l,
+	   _UIntType __f>
+    constexpr _UIntType
+    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d,
+			    __s, __b, __t, __c, __l, __f>::xor_mask;
+
+  template<typename _UIntType,
+	   size_t __w, size_t __n, size_t __m, size_t __r,
+	   _UIntType __a, size_t __u, _UIntType __d, size_t __s,
+	   _UIntType __b, size_t __t, _UIntType __c, size_t __l,
+	   _UIntType __f>
+    constexpr size_t
+    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d,
+			    __s, __b, __t, __c, __l, __f>::tempering_u;
+   
+  template<typename _UIntType,
+	   size_t __w, size_t __n, size_t __m, size_t __r,
+	   _UIntType __a, size_t __u, _UIntType __d, size_t __s,
+	   _UIntType __b, size_t __t, _UIntType __c, size_t __l,
+	   _UIntType __f>
+    constexpr _UIntType
+    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d,
+			    __s, __b, __t, __c, __l, __f>::tempering_d;
+
+  template<typename _UIntType,
+	   size_t __w, size_t __n, size_t __m, size_t __r,
+	   _UIntType __a, size_t __u, _UIntType __d, size_t __s,
+	   _UIntType __b, size_t __t, _UIntType __c, size_t __l,
+	   _UIntType __f>
+    constexpr size_t
+    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d,
+			    __s, __b, __t, __c, __l, __f>::tempering_s;
+
+  template<typename _UIntType,
+	   size_t __w, size_t __n, size_t __m, size_t __r,
+	   _UIntType __a, size_t __u, _UIntType __d, size_t __s,
+	   _UIntType __b, size_t __t, _UIntType __c, size_t __l,
+	   _UIntType __f>
+    constexpr _UIntType
+    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d,
+			    __s, __b, __t, __c, __l, __f>::tempering_b;
+
+  template<typename _UIntType,
+	   size_t __w, size_t __n, size_t __m, size_t __r,
+	   _UIntType __a, size_t __u, _UIntType __d, size_t __s,
+	   _UIntType __b, size_t __t, _UIntType __c, size_t __l,
+	   _UIntType __f>
+    constexpr size_t
+    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d,
+			    __s, __b, __t, __c, __l, __f>::tempering_t;
+
+  template<typename _UIntType,
+	   size_t __w, size_t __n, size_t __m, size_t __r,
+	   _UIntType __a, size_t __u, _UIntType __d, size_t __s,
+	   _UIntType __b, size_t __t, _UIntType __c, size_t __l,
+	   _UIntType __f>
+    constexpr _UIntType
+    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d,
+			    __s, __b, __t, __c, __l, __f>::tempering_c;
+
+  template<typename _UIntType,
+	   size_t __w, size_t __n, size_t __m, size_t __r,
+	   _UIntType __a, size_t __u, _UIntType __d, size_t __s,
+	   _UIntType __b, size_t __t, _UIntType __c, size_t __l,
+	   _UIntType __f>
+    constexpr size_t
+    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d,
+			    __s, __b, __t, __c, __l, __f>::tempering_l;
+
+  template<typename _UIntType,
+	   size_t __w, size_t __n, size_t __m, size_t __r,
+	   _UIntType __a, size_t __u, _UIntType __d, size_t __s,
+	   _UIntType __b, size_t __t, _UIntType __c, size_t __l,
+	   _UIntType __f>
+    constexpr _UIntType
+    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d,
+			    __s, __b, __t, __c, __l, __f>::
+                                              initialization_multiplier;
+
+  template<typename _UIntType,
+	   size_t __w, size_t __n, size_t __m, size_t __r,
+	   _UIntType __a, size_t __u, _UIntType __d, size_t __s,
+	   _UIntType __b, size_t __t, _UIntType __c, size_t __l,
+	   _UIntType __f>
+    constexpr _UIntType
+    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d,
+			    __s, __b, __t, __c, __l, __f>::default_seed;
+#endif
+
+  template<typename _UIntType,
+	   size_t __w, size_t __n, size_t __m, size_t __r,
+	   _UIntType __a, size_t __u, _UIntType __d, size_t __s,
+	   _UIntType __b, size_t __t, _UIntType __c, size_t __l,
+	   _UIntType __f>
+    void
+    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d,
+			    __s, __b, __t, __c, __l, __f>::
+    seed(result_type __sd)
+    {
+      _M_x[0] = __detail::__mod<_UIntType,
+	__detail::_Shift<_UIntType, __w>::__value>(__sd);
+
+      for (size_t __i = 1; __i < state_size; ++__i)
+	{
+	  _UIntType __x = _M_x[__i - 1];
+	  __x ^= __x >> (__w - 2);
+	  __x *= __f;
+	  __x += __detail::__mod<_UIntType, __n>(__i);
+	  _M_x[__i] = __detail::__mod<_UIntType,
+	    __detail::_Shift<_UIntType, __w>::__value>(__x);
+	}
+      _M_p = state_size;
+    }
+
+  template<typename _UIntType,
+	   size_t __w, size_t __n, size_t __m, size_t __r,
+	   _UIntType __a, size_t __u, _UIntType __d, size_t __s,
+	   _UIntType __b, size_t __t, _UIntType __c, size_t __l,
+	   _UIntType __f>
+    template<typename _Sseq>
+      auto
+      mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d,
+			      __s, __b, __t, __c, __l, __f>::
+      seed(_Sseq& __q)
+      -> _If_seed_seq<_Sseq>
+      {
+	const _UIntType __upper_mask = (~_UIntType()) << __r;
+	const size_t __k = (__w + 31) / 32;
+	uint_least32_t __arr[__n * __k];
+	__q.generate(__arr + 0, __arr + __n * __k);
+
+	bool __zero = true;
+	for (size_t __i = 0; __i < state_size; ++__i)
+	  {
+	    _UIntType __factor = 1u;
+	    _UIntType __sum = 0u;
+	    for (size_t __j = 0; __j < __k; ++__j)
+	      {
+		__sum += __arr[__k * __i + __j] * __factor;
+		__factor *= __detail::_Shift<_UIntType, 32>::__value;
+	      }
+	    _M_x[__i] = __detail::__mod<_UIntType,
+	      __detail::_Shift<_UIntType, __w>::__value>(__sum);
+
+	    if (__zero)
+	      {
+		if (__i == 0)
+		  {
+		    if ((_M_x[0] & __upper_mask) != 0u)
+		      __zero = false;
+		  }
+		else if (_M_x[__i] != 0u)
+		  __zero = false;
+	      }
+	  }
+        if (__zero)
+          _M_x[0] = __detail::_Shift<_UIntType, __w - 1>::__value;
+	_M_p = state_size;
+      }
+
+  template<typename _UIntType, size_t __w,
+	   size_t __n, size_t __m, size_t __r,
+	   _UIntType __a, size_t __u, _UIntType __d, size_t __s,
+	   _UIntType __b, size_t __t, _UIntType __c, size_t __l,
+	   _UIntType __f>
+    void
+    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d,
+			    __s, __b, __t, __c, __l, __f>::
+    _M_gen_rand(void)
+    {
+      const _UIntType __upper_mask = (~_UIntType()) << __r;
+      const _UIntType __lower_mask = ~__upper_mask;
+
+      for (size_t __k = 0; __k < (__n - __m); ++__k)
+        {
+	  _UIntType __y = ((_M_x[__k] & __upper_mask)
+			   | (_M_x[__k + 1] & __lower_mask));
+	  _M_x[__k] = (_M_x[__k + __m] ^ (__y >> 1)
+		       ^ ((__y & 0x01) ? __a : 0));
+        }
+
+      for (size_t __k = (__n - __m); __k < (__n - 1); ++__k)
+	{
+	  _UIntType __y = ((_M_x[__k] & __upper_mask)
+			   | (_M_x[__k + 1] & __lower_mask));
+	  _M_x[__k] = (_M_x[__k + (__m - __n)] ^ (__y >> 1)
+		       ^ ((__y & 0x01) ? __a : 0));
+	}
+
+      _UIntType __y = ((_M_x[__n - 1] & __upper_mask)
+		       | (_M_x[0] & __lower_mask));
+      _M_x[__n - 1] = (_M_x[__m - 1] ^ (__y >> 1)
+		       ^ ((__y & 0x01) ? __a : 0));
+      _M_p = 0;
+    }
+
+  template<typename _UIntType, size_t __w,
+	   size_t __n, size_t __m, size_t __r,
+	   _UIntType __a, size_t __u, _UIntType __d, size_t __s,
+	   _UIntType __b, size_t __t, _UIntType __c, size_t __l,
+	   _UIntType __f>
+    void
+    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d,
+			    __s, __b, __t, __c, __l, __f>::
+    discard(unsigned long long __z)
+    {
+      while (__z > state_size - _M_p)
+	{
+	  __z -= state_size - _M_p;
+	  _M_gen_rand();
+	}
+      _M_p += __z;
+    }
+
+  template<typename _UIntType, size_t __w,
+	   size_t __n, size_t __m, size_t __r,
+	   _UIntType __a, size_t __u, _UIntType __d, size_t __s,
+	   _UIntType __b, size_t __t, _UIntType __c, size_t __l,
+	   _UIntType __f>
+    typename
+    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d,
+			    __s, __b, __t, __c, __l, __f>::result_type
+    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d,
+			    __s, __b, __t, __c, __l, __f>::
+    operator()()
+    {
+      // Reload the vector - cost is O(n) amortized over n calls.
+      if (_M_p >= state_size)
+	_M_gen_rand();
+
+      // Calculate o(x(i)).
+      result_type __z = _M_x[_M_p++];
+      __z ^= (__z >> __u) & __d;
+      __z ^= (__z << __s) & __b;
+      __z ^= (__z << __t) & __c;
+      __z ^= (__z >> __l);
+
+      return __z;
+    }
+
+  template<typename _UIntType, size_t __w,
+	   size_t __n, size_t __m, size_t __r,
+	   _UIntType __a, size_t __u, _UIntType __d, size_t __s,
+	   _UIntType __b, size_t __t, _UIntType __c, size_t __l,
+	   _UIntType __f, typename _CharT, typename _Traits>
+    std::basic_ostream<_CharT, _Traits>&
+    operator<<(std::basic_ostream<_CharT, _Traits>& __os,
+	       const mersenne_twister_engine<_UIntType, __w, __n, __m,
+	       __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>& __x)
+    {
+      using __ios_base = typename basic_ostream<_CharT, _Traits>::ios_base;
+
+      const typename __ios_base::fmtflags __flags = __os.flags();
+      const _CharT __fill = __os.fill();
+      const _CharT __space = __os.widen(' ');
+      __os.flags(__ios_base::dec | __ios_base::fixed | __ios_base::left);
+      __os.fill(__space);
+
+      for (size_t __i = 0; __i < __n; ++__i)
+	__os << __x._M_x[__i] << __space;
+      __os << __x._M_p;
+
+      __os.flags(__flags);
+      __os.fill(__fill);
+      return __os;
+    }
+
+  template<typename _UIntType, size_t __w,
+	   size_t __n, size_t __m, size_t __r,
+	   _UIntType __a, size_t __u, _UIntType __d, size_t __s,
+	   _UIntType __b, size_t __t, _UIntType __c, size_t __l,
+	   _UIntType __f, typename _CharT, typename _Traits>
+    std::basic_istream<_CharT, _Traits>&
+    operator>>(std::basic_istream<_CharT, _Traits>& __is,
+	       mersenne_twister_engine<_UIntType, __w, __n, __m,
+	       __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>& __x)
+    {
+      using __ios_base = typename basic_istream<_CharT, _Traits>::ios_base;
+
+      const typename __ios_base::fmtflags __flags = __is.flags();
+      __is.flags(__ios_base::dec | __ios_base::skipws);
+
+      for (size_t __i = 0; __i < __n; ++__i)
+	__is >> __x._M_x[__i];
+      __is >> __x._M_p;
+
+      __is.flags(__flags);
+      return __is;
+    }
+
+#if ! __cpp_inline_variables
+  template<typename _UIntType, size_t __w, size_t __s, size_t __r>
+    constexpr size_t
+    subtract_with_carry_engine<_UIntType, __w, __s, __r>::word_size;
+
+  template<typename _UIntType, size_t __w, size_t __s, size_t __r>
+    constexpr size_t
+    subtract_with_carry_engine<_UIntType, __w, __s, __r>::short_lag;
+
+  template<typename _UIntType, size_t __w, size_t __s, size_t __r>
+    constexpr size_t
+    subtract_with_carry_engine<_UIntType, __w, __s, __r>::long_lag;
+
+  template<typename _UIntType, size_t __w, size_t __s, size_t __r>
+    constexpr _UIntType
+    subtract_with_carry_engine<_UIntType, __w, __s, __r>::default_seed;
+#endif
+
+  template<typename _UIntType, size_t __w, size_t __s, size_t __r>
+    void
+    subtract_with_carry_engine<_UIntType, __w, __s, __r>::
+    seed(result_type __value)
+    {
+      std::linear_congruential_engine<result_type, 40014u, 0u, 2147483563u>
+	__lcg(__value == 0u ? default_seed : __value);
+
+      const size_t __n = (__w + 31) / 32;
+
+      for (size_t __i = 0; __i < long_lag; ++__i)
+	{
+	  _UIntType __sum = 0u;
+	  _UIntType __factor = 1u;
+	  for (size_t __j = 0; __j < __n; ++__j)
+	    {
+	      __sum += __detail::__mod<uint_least32_t,
+		       __detail::_Shift<uint_least32_t, 32>::__value>
+			 (__lcg()) * __factor;
+	      __factor *= __detail::_Shift<_UIntType, 32>::__value;
+	    }
+	  _M_x[__i] = __detail::__mod<_UIntType,
+	    __detail::_Shift<_UIntType, __w>::__value>(__sum);
+	}
+      _M_carry = (_M_x[long_lag - 1] == 0) ? 1 : 0;
+      _M_p = 0;
+    }
+
+  template<typename _UIntType, size_t __w, size_t __s, size_t __r>
+    template<typename _Sseq>
+      auto
+      subtract_with_carry_engine<_UIntType, __w, __s, __r>::
+      seed(_Sseq& __q)
+      -> _If_seed_seq<_Sseq>
+      {
+	const size_t __k = (__w + 31) / 32;
+	uint_least32_t __arr[__r * __k];
+	__q.generate(__arr + 0, __arr + __r * __k);
+
+	for (size_t __i = 0; __i < long_lag; ++__i)
+	  {
+	    _UIntType __sum = 0u;
+	    _UIntType __factor = 1u;
+	    for (size_t __j = 0; __j < __k; ++__j)
+	      {
+		__sum += __arr[__k * __i + __j] * __factor;
+		__factor *= __detail::_Shift<_UIntType, 32>::__value;
+	      }
+	    _M_x[__i] = __detail::__mod<_UIntType,
+	      __detail::_Shift<_UIntType, __w>::__value>(__sum);
+	  }
+	_M_carry = (_M_x[long_lag - 1] == 0) ? 1 : 0;
+	_M_p = 0;
+      }
+
+  template<typename _UIntType, size_t __w, size_t __s, size_t __r>
+    typename subtract_with_carry_engine<_UIntType, __w, __s, __r>::
+	     result_type
+    subtract_with_carry_engine<_UIntType, __w, __s, __r>::
+    operator()()
+    {
+      // Derive short lag index from current index.
+      long __ps = _M_p - short_lag;
+      if (__ps < 0)
+	__ps += long_lag;
+
+      // Calculate new x(i) without overflow or division.
+      // NB: Thanks to the requirements for _UIntType, _M_x[_M_p] + _M_carry
+      // cannot overflow.
+      _UIntType __xi;
+      if (_M_x[__ps] >= _M_x[_M_p] + _M_carry)
+	{
+	  __xi = _M_x[__ps] - _M_x[_M_p] - _M_carry;
+	  _M_carry = 0;
+	}
+      else
+	{
+	  __xi = (__detail::_Shift<_UIntType, __w>::__value
+		  - _M_x[_M_p] - _M_carry + _M_x[__ps]);
+	  _M_carry = 1;
+	}
+      _M_x[_M_p] = __xi;
+
+      // Adjust current index to loop around in ring buffer.
+      if (++_M_p >= long_lag)
+	_M_p = 0;
+
+      return __xi;
+    }
+
+  template<typename _UIntType, size_t __w, size_t __s, size_t __r,
+	   typename _CharT, typename _Traits>
+    std::basic_ostream<_CharT, _Traits>&
+    operator<<(std::basic_ostream<_CharT, _Traits>& __os,
+	       const subtract_with_carry_engine<_UIntType,
+						__w, __s, __r>& __x)
+    {
+      using __ios_base = typename basic_ostream<_CharT, _Traits>::ios_base;
+
+      const typename __ios_base::fmtflags __flags = __os.flags();
+      const _CharT __fill = __os.fill();
+      const _CharT __space = __os.widen(' ');
+      __os.flags(__ios_base::dec | __ios_base::fixed | __ios_base::left);
+      __os.fill(__space);
+
+      for (size_t __i = 0; __i < __r; ++__i)
+	__os << __x._M_x[__i] << __space;
+      __os << __x._M_carry << __space << __x._M_p;
+
+      __os.flags(__flags);
+      __os.fill(__fill);
+      return __os;
+    }
+
+  template<typename _UIntType, size_t __w, size_t __s, size_t __r,
+	   typename _CharT, typename _Traits>
+    std::basic_istream<_CharT, _Traits>&
+    operator>>(std::basic_istream<_CharT, _Traits>& __is,
+	       subtract_with_carry_engine<_UIntType, __w, __s, __r>& __x)
+    {
+      using __ios_base = typename basic_istream<_CharT, _Traits>::ios_base;
+
+      const typename __ios_base::fmtflags __flags = __is.flags();
+      __is.flags(__ios_base::dec | __ios_base::skipws);
+
+      for (size_t __i = 0; __i < __r; ++__i)
+	__is >> __x._M_x[__i];
+      __is >> __x._M_carry;
+      __is >> __x._M_p;
+
+      __is.flags(__flags);
+      return __is;
+    }
+
+#if ! __cpp_inline_variables
+  template<typename _RandomNumberEngine, size_t __p, size_t __r>
+    constexpr size_t
+    discard_block_engine<_RandomNumberEngine, __p, __r>::block_size;
+
+  template<typename _RandomNumberEngine, size_t __p, size_t __r>
+    constexpr size_t
+    discard_block_engine<_RandomNumberEngine, __p, __r>::used_block;
+#endif
+
+  template<typename _RandomNumberEngine, size_t __p, size_t __r>
+    typename discard_block_engine<_RandomNumberEngine,
+			   __p, __r>::result_type
+    discard_block_engine<_RandomNumberEngine, __p, __r>::
+    operator()()
+    {
+      if (_M_n >= used_block)
+	{
+	  _M_b.discard(block_size - _M_n);
+	  _M_n = 0;
+	}
+      ++_M_n;
+      return _M_b();
+    }
+
+  template<typename _RandomNumberEngine, size_t __p, size_t __r,
+	   typename _CharT, typename _Traits>
+    std::basic_ostream<_CharT, _Traits>&
+    operator<<(std::basic_ostream<_CharT, _Traits>& __os,
+	       const discard_block_engine<_RandomNumberEngine,
+	       __p, __r>& __x)
+    {
+      using __ios_base = typename basic_ostream<_CharT, _Traits>::ios_base;
+
+      const typename __ios_base::fmtflags __flags = __os.flags();
+      const _CharT __fill = __os.fill();
+      const _CharT __space = __os.widen(' ');
+      __os.flags(__ios_base::dec | __ios_base::fixed | __ios_base::left);
+      __os.fill(__space);
+
+      __os << __x.base() << __space << __x._M_n;
+
+      __os.flags(__flags);
+      __os.fill(__fill);
+      return __os;
+    }
+
+  template<typename _RandomNumberEngine, size_t __p, size_t __r,
+	   typename _CharT, typename _Traits>
+    std::basic_istream<_CharT, _Traits>&
+    operator>>(std::basic_istream<_CharT, _Traits>& __is,
+	       discard_block_engine<_RandomNumberEngine, __p, __r>& __x)
+    {
+      using __ios_base = typename basic_istream<_CharT, _Traits>::ios_base;
+
+      const typename __ios_base::fmtflags __flags = __is.flags();
+      __is.flags(__ios_base::dec | __ios_base::skipws);
+
+      __is >> __x._M_b >> __x._M_n;
+
+      __is.flags(__flags);
+      return __is;
+    }
+
+
+  template<typename _RandomNumberEngine, size_t __w, typename _UIntType>
+    typename independent_bits_engine<_RandomNumberEngine, __w, _UIntType>::
+      result_type
+    independent_bits_engine<_RandomNumberEngine, __w, _UIntType>::
+    operator()()
+    {
+      typedef typename _RandomNumberEngine::result_type _Eresult_type;
+      const _Eresult_type __r
+	= (_M_b.max() - _M_b.min() < std::numeric_limits<_Eresult_type>::max()
+	   ? _M_b.max() - _M_b.min() + 1 : 0);
+      const unsigned __edig = std::numeric_limits<_Eresult_type>::digits;
+      const unsigned __m = __r ? std::__lg(__r) : __edig;
+
+      typedef typename std::common_type<_Eresult_type, result_type>::type
+	__ctype;
+      const unsigned __cdig = std::numeric_limits<__ctype>::digits;
+
+      unsigned __n, __n0;
+      __ctype __s0, __s1, __y0, __y1;
+
+      for (size_t __i = 0; __i < 2; ++__i)
+	{
+	  __n = (__w + __m - 1) / __m + __i;
+	  __n0 = __n - __w % __n;
+	  const unsigned __w0 = __w / __n;  // __w0 <= __m
+
+	  __s0 = 0;
+	  __s1 = 0;
+	  if (__w0 < __cdig)
+	    {
+	      __s0 = __ctype(1) << __w0;
+	      __s1 = __s0 << 1;
+	    }
+
+	  __y0 = 0;
+	  __y1 = 0;
+	  if (__r)
+	    {
+	      __y0 = __s0 * (__r / __s0);
+	      if (__s1)
+		__y1 = __s1 * (__r / __s1);
+
+	      if (__r - __y0 <= __y0 / __n)
+		break;
+	    }
+	  else
+	    break;
+	}
+
+      result_type __sum = 0;
+      for (size_t __k = 0; __k < __n0; ++__k)
+	{
+	  __ctype __u;
+	  do
+	    __u = _M_b() - _M_b.min();
+	  while (__y0 && __u >= __y0);
+	  __sum = __s0 * __sum + (__s0 ? __u % __s0 : __u);
+	}
+      for (size_t __k = __n0; __k < __n; ++__k)
+	{
+	  __ctype __u;
+	  do
+	    __u = _M_b() - _M_b.min();
+	  while (__y1 && __u >= __y1);
+	  __sum = __s1 * __sum + (__s1 ? __u % __s1 : __u);
+	}
+      return __sum;
+    }
+
+#if ! __cpp_inline_variables
+  template<typename _RandomNumberEngine, size_t __k>
+    constexpr size_t
+    shuffle_order_engine<_RandomNumberEngine, __k>::table_size;
+#endif
+
+  namespace __detail
+  {
+    // Determine whether an integer is representable as double.
+    template<typename _Tp>
+      constexpr bool
+      __representable_as_double(_Tp __x) noexcept
+      {
+	static_assert(numeric_limits<_Tp>::is_integer, "");
+	static_assert(!numeric_limits<_Tp>::is_signed, "");
+	// All integers <= 2^53 are representable.
+	return (__x <= (1ull << __DBL_MANT_DIG__))
+	  // Between 2^53 and 2^54 only even numbers are representable.
+	  || (!(__x & 1) && __detail::__representable_as_double(__x >> 1));
+      }
+
+    // Determine whether x+1 is representable as double.
+    template<typename _Tp>
+      constexpr bool
+      __p1_representable_as_double(_Tp __x) noexcept
+      {
+	static_assert(numeric_limits<_Tp>::is_integer, "");
+	static_assert(!numeric_limits<_Tp>::is_signed, "");
+	return numeric_limits<_Tp>::digits < __DBL_MANT_DIG__
+	  || (bool(__x + 1u) // return false if x+1 wraps around to zero
+	      && __detail::__representable_as_double(__x + 1u));
+      }
+  }
+
+  template<typename _RandomNumberEngine, size_t __k>
+    typename shuffle_order_engine<_RandomNumberEngine, __k>::result_type
+    shuffle_order_engine<_RandomNumberEngine, __k>::
+    operator()()
+    {
+      constexpr result_type __range = max() - min();
+      size_t __j = __k;
+      const result_type __y = _M_y - min();
+      // Avoid using slower long double arithmetic if possible.
+      if _GLIBCXX17_CONSTEXPR (__detail::__p1_representable_as_double(__range))
+	__j *= __y / (__range + 1.0);
+      else
+	__j *= __y / (__range + 1.0L);
+      _M_y = _M_v[__j];
+      _M_v[__j] = _M_b();
+
+      return _M_y;
+    }
+
+  template<typename _RandomNumberEngine, size_t __k,
+	   typename _CharT, typename _Traits>
+    std::basic_ostream<_CharT, _Traits>&
+    operator<<(std::basic_ostream<_CharT, _Traits>& __os,
+	       const shuffle_order_engine<_RandomNumberEngine, __k>& __x)
+    {
+      using __ios_base = typename basic_ostream<_CharT, _Traits>::ios_base;
+
+      const typename __ios_base::fmtflags __flags = __os.flags();
+      const _CharT __fill = __os.fill();
+      const _CharT __space = __os.widen(' ');
+      __os.flags(__ios_base::dec | __ios_base::fixed | __ios_base::left);
+      __os.fill(__space);
+
+      __os << __x.base();
+      for (size_t __i = 0; __i < __k; ++__i)
+	__os << __space << __x._M_v[__i];
+      __os << __space << __x._M_y;
+
+      __os.flags(__flags);
+      __os.fill(__fill);
+      return __os;
+    }
+
+  template<typename _RandomNumberEngine, size_t __k,
+	   typename _CharT, typename _Traits>
+    std::basic_istream<_CharT, _Traits>&
+    operator>>(std::basic_istream<_CharT, _Traits>& __is,
+	       shuffle_order_engine<_RandomNumberEngine, __k>& __x)
+    {
+      using __ios_base = typename basic_istream<_CharT, _Traits>::ios_base;
+
+      const typename __ios_base::fmtflags __flags = __is.flags();
+      __is.flags(__ios_base::dec | __ios_base::skipws);
+
+      __is >> __x._M_b;
+      for (size_t __i = 0; __i < __k; ++__i)
+	__is >> __x._M_v[__i];
+      __is >> __x._M_y;
+
+      __is.flags(__flags);
+      return __is;
+    }
+
+
+  template<typename _IntType, typename _CharT, typename _Traits>
+    std::basic_ostream<_CharT, _Traits>&
+    operator<<(std::basic_ostream<_CharT, _Traits>& __os,
+	       const uniform_int_distribution<_IntType>& __x)
+    {
+      using __ios_base = typename basic_ostream<_CharT, _Traits>::ios_base;
+
+      const typename __ios_base::fmtflags __flags = __os.flags();
+      const _CharT __fill = __os.fill();
+      const _CharT __space = __os.widen(' ');
+      __os.flags(__ios_base::scientific | __ios_base::left);
+      __os.fill(__space);
+
+      __os << __x.a() << __space << __x.b();
+
+      __os.flags(__flags);
+      __os.fill(__fill);
+      return __os;
+    }
+
+  template<typename _IntType, typename _CharT, typename _Traits>
+    std::basic_istream<_CharT, _Traits>&
+    operator>>(std::basic_istream<_CharT, _Traits>& __is,
+	       uniform_int_distribution<_IntType>& __x)
+    {
+      using param_type
+	= typename uniform_int_distribution<_IntType>::param_type;
+      using __ios_base = typename basic_istream<_CharT, _Traits>::ios_base;
+
+      const typename __ios_base::fmtflags __flags = __is.flags();
+      __is.flags(__ios_base::dec | __ios_base::skipws);
+
+      _IntType __a, __b;
+      if (__is >> __a >> __b)
+	__x.param(param_type(__a, __b));
+
+      __is.flags(__flags);
+      return __is;
+    }
+
+
+  template<typename _RealType>
+    template<typename _ForwardIterator,
+	     typename _UniformRandomNumberGenerator>
+      void
+      uniform_real_distribution<_RealType>::
+      __generate_impl(_ForwardIterator __f, _ForwardIterator __t,
+		      _UniformRandomNumberGenerator& __urng,
+		      const param_type& __p)
+      {
+	__glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+	__detail::_Adaptor<_UniformRandomNumberGenerator, result_type>
+	  __aurng(__urng);
+	auto __range = __p.b() - __p.a();
+	while (__f != __t)
+	  *__f++ = __aurng() * __range + __p.a();
+      }
+
+  template<typename _RealType, typename _CharT, typename _Traits>
+    std::basic_ostream<_CharT, _Traits>&
+    operator<<(std::basic_ostream<_CharT, _Traits>& __os,
+	       const uniform_real_distribution<_RealType>& __x)
+    {
+      using __ios_base = typename basic_ostream<_CharT, _Traits>::ios_base;
+
+      const typename __ios_base::fmtflags __flags = __os.flags();
+      const _CharT __fill = __os.fill();
+      const std::streamsize __precision = __os.precision();
+      const _CharT __space = __os.widen(' ');
+      __os.flags(__ios_base::scientific | __ios_base::left);
+      __os.fill(__space);
+      __os.precision(std::numeric_limits<_RealType>::max_digits10);
+
+      __os << __x.a() << __space << __x.b();
+
+      __os.flags(__flags);
+      __os.fill(__fill);
+      __os.precision(__precision);
+      return __os;
+    }
+
+  template<typename _RealType, typename _CharT, typename _Traits>
+    std::basic_istream<_CharT, _Traits>&
+    operator>>(std::basic_istream<_CharT, _Traits>& __is,
+	       uniform_real_distribution<_RealType>& __x)
+    {
+      using param_type
+	= typename uniform_real_distribution<_RealType>::param_type;
+      using __ios_base = typename basic_istream<_CharT, _Traits>::ios_base;
+
+      const typename __ios_base::fmtflags __flags = __is.flags();
+      __is.flags(__ios_base::skipws);
+
+      _RealType __a, __b;
+      if (__is >> __a >> __b)
+	__x.param(param_type(__a, __b));
+
+      __is.flags(__flags);
+      return __is;
+    }
+
+
+  template<typename _ForwardIterator,
+	   typename _UniformRandomNumberGenerator>
+    void
+    std::bernoulli_distribution::
+    __generate_impl(_ForwardIterator __f, _ForwardIterator __t,
+		    _UniformRandomNumberGenerator& __urng,
+		    const param_type& __p)
+    {
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+      __detail::_Adaptor<_UniformRandomNumberGenerator, double>
+	__aurng(__urng);
+      auto __limit = __p.p() * (__aurng.max() - __aurng.min());
+
+      while (__f != __t)
+	*__f++ = (__aurng() - __aurng.min()) < __limit;
+    }
+
+  template<typename _CharT, typename _Traits>
+    std::basic_ostream<_CharT, _Traits>&
+    operator<<(std::basic_ostream<_CharT, _Traits>& __os,
+	       const bernoulli_distribution& __x)
+    {
+      using __ios_base = typename basic_ostream<_CharT, _Traits>::ios_base;
+
+      const typename __ios_base::fmtflags __flags = __os.flags();
+      const _CharT __fill = __os.fill();
+      const std::streamsize __precision = __os.precision();
+      __os.flags(__ios_base::scientific | __ios_base::left);
+      __os.fill(__os.widen(' '));
+      __os.precision(std::numeric_limits<double>::max_digits10);
+
+      __os << __x.p();
+
+      __os.flags(__flags);
+      __os.fill(__fill);
+      __os.precision(__precision);
+      return __os;
+    }
+
+
+  template<typename _IntType>
+    template<typename _UniformRandomNumberGenerator>
+      typename geometric_distribution<_IntType>::result_type
+      geometric_distribution<_IntType>::
+      operator()(_UniformRandomNumberGenerator& __urng,
+		 const param_type& __param)
+      {
+	// About the epsilon thing see this thread:
+	// http://gcc.gnu.org/ml/gcc-patches/2006-10/msg00971.html
+	const double __naf =
+	  (1 - std::numeric_limits<double>::epsilon()) / 2;
+	// The largest _RealType convertible to _IntType.
+	const double __thr =
+	  std::numeric_limits<_IntType>::max() + __naf;
+	__detail::_Adaptor<_UniformRandomNumberGenerator, double>
+	  __aurng(__urng);
+
+	double __cand;
+	do
+	  __cand = std::floor(std::log(1.0 - __aurng()) / __param._M_log_1_p);
+	while (__cand >= __thr);
+
+	return result_type(__cand + __naf);
+      }
+
+  template<typename _IntType>
+    template<typename _ForwardIterator,
+	     typename _UniformRandomNumberGenerator>
+      void
+      geometric_distribution<_IntType>::
+      __generate_impl(_ForwardIterator __f, _ForwardIterator __t,
+		      _UniformRandomNumberGenerator& __urng,
+		      const param_type& __param)
+      {
+	__glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+	// About the epsilon thing see this thread:
+	// http://gcc.gnu.org/ml/gcc-patches/2006-10/msg00971.html
+	const double __naf =
+	  (1 - std::numeric_limits<double>::epsilon()) / 2;
+	// The largest _RealType convertible to _IntType.
+	const double __thr =
+	  std::numeric_limits<_IntType>::max() + __naf;
+	__detail::_Adaptor<_UniformRandomNumberGenerator, double>
+	  __aurng(__urng);
+
+	while (__f != __t)
+	  {
+	    double __cand;
+	    do
+	      __cand = std::floor(std::log(1.0 - __aurng())
+				  / __param._M_log_1_p);
+	    while (__cand >= __thr);
+
+	    *__f++ = __cand + __naf;
+	  }
+      }
+
+  template<typename _IntType,
+	   typename _CharT, typename _Traits>
+    std::basic_ostream<_CharT, _Traits>&
+    operator<<(std::basic_ostream<_CharT, _Traits>& __os,
+	       const geometric_distribution<_IntType>& __x)
+    {
+      using __ios_base = typename basic_ostream<_CharT, _Traits>::ios_base;
+
+      const typename __ios_base::fmtflags __flags = __os.flags();
+      const _CharT __fill = __os.fill();
+      const std::streamsize __precision = __os.precision();
+      __os.flags(__ios_base::scientific | __ios_base::left);
+      __os.fill(__os.widen(' '));
+      __os.precision(std::numeric_limits<double>::max_digits10);
+
+      __os << __x.p();
+
+      __os.flags(__flags);
+      __os.fill(__fill);
+      __os.precision(__precision);
+      return __os;
+    }
+
+  template<typename _IntType,
+	   typename _CharT, typename _Traits>
+    std::basic_istream<_CharT, _Traits>&
+    operator>>(std::basic_istream<_CharT, _Traits>& __is,
+	       geometric_distribution<_IntType>& __x)
+    {
+      using param_type = typename geometric_distribution<_IntType>::param_type;
+      using __ios_base = typename basic_istream<_CharT, _Traits>::ios_base;
+
+      const typename __ios_base::fmtflags __flags = __is.flags();
+      __is.flags(__ios_base::skipws);
+
+      double __p;
+      if (__is >> __p)
+	__x.param(param_type(__p));
+
+      __is.flags(__flags);
+      return __is;
+    }
+
+  // This is Leger's algorithm, also in Devroye, Ch. X, Example 1.5.
+  template<typename _IntType>
+    template<typename _UniformRandomNumberGenerator>
+      typename negative_binomial_distribution<_IntType>::result_type
+      negative_binomial_distribution<_IntType>::
+      operator()(_UniformRandomNumberGenerator& __urng)
+      {
+	const double __y = _M_gd(__urng);
+
+	// XXX Is the constructor too slow?
+	std::poisson_distribution<result_type> __poisson(__y);
+	return __poisson(__urng);
+      }
+
+  template<typename _IntType>
+    template<typename _UniformRandomNumberGenerator>
+      typename negative_binomial_distribution<_IntType>::result_type
+      negative_binomial_distribution<_IntType>::
+      operator()(_UniformRandomNumberGenerator& __urng,
+		 const param_type& __p)
+      {
+	typedef typename std::gamma_distribution<double>::param_type
+	  param_type;
+	
+	const double __y =
+	  _M_gd(__urng, param_type(__p.k(), (1.0 - __p.p()) / __p.p()));
+
+	std::poisson_distribution<result_type> __poisson(__y);
+	return __poisson(__urng);
+      }
+
+  template<typename _IntType>
+    template<typename _ForwardIterator,
+	     typename _UniformRandomNumberGenerator>
+      void
+      negative_binomial_distribution<_IntType>::
+      __generate_impl(_ForwardIterator __f, _ForwardIterator __t,
+		      _UniformRandomNumberGenerator& __urng)
+      {
+	__glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+	while (__f != __t)
+	  {
+	    const double __y = _M_gd(__urng);
+
+	    // XXX Is the constructor too slow?
+	    std::poisson_distribution<result_type> __poisson(__y);
+	    *__f++ = __poisson(__urng);
+	  }
+      }
+
+  template<typename _IntType>
+    template<typename _ForwardIterator,
+	     typename _UniformRandomNumberGenerator>
+      void
+      negative_binomial_distribution<_IntType>::
+      __generate_impl(_ForwardIterator __f, _ForwardIterator __t,
+		      _UniformRandomNumberGenerator& __urng,
+		      const param_type& __p)
+      {
+	__glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+	typename std::gamma_distribution<result_type>::param_type
+	  __p2(__p.k(), (1.0 - __p.p()) / __p.p());
+
+	while (__f != __t)
+	  {
+	    const double __y = _M_gd(__urng, __p2);
+
+	    std::poisson_distribution<result_type> __poisson(__y);
+	    *__f++ = __poisson(__urng);
+	  }
+      }
+
+  template<typename _IntType, typename _CharT, typename _Traits>
+    std::basic_ostream<_CharT, _Traits>&
+    operator<<(std::basic_ostream<_CharT, _Traits>& __os,
+	       const negative_binomial_distribution<_IntType>& __x)
+    {
+      using __ios_base = typename basic_ostream<_CharT, _Traits>::ios_base;
+
+      const typename __ios_base::fmtflags __flags = __os.flags();
+      const _CharT __fill = __os.fill();
+      const std::streamsize __precision = __os.precision();
+      const _CharT __space = __os.widen(' ');
+      __os.flags(__ios_base::scientific | __ios_base::left);
+      __os.fill(__os.widen(' '));
+      __os.precision(std::numeric_limits<double>::max_digits10);
+
+      __os << __x.k() << __space << __x.p()
+	   << __space << __x._M_gd;
+
+      __os.flags(__flags);
+      __os.fill(__fill);
+      __os.precision(__precision);
+      return __os;
+    }
+
+  template<typename _IntType, typename _CharT, typename _Traits>
+    std::basic_istream<_CharT, _Traits>&
+    operator>>(std::basic_istream<_CharT, _Traits>& __is,
+	       negative_binomial_distribution<_IntType>& __x)
+    {
+      using param_type
+	= typename negative_binomial_distribution<_IntType>::param_type;
+      using __ios_base = typename basic_istream<_CharT, _Traits>::ios_base;
+
+      const typename __ios_base::fmtflags __flags = __is.flags();
+      __is.flags(__ios_base::skipws);
+
+      _IntType __k;
+      double __p;
+      if (__is >> __k >> __p >> __x._M_gd)
+	__x.param(param_type(__k, __p));
+
+      __is.flags(__flags);
+      return __is;
+    }
+
+
+  template<typename _IntType>
+    void
+    poisson_distribution<_IntType>::param_type::
+    _M_initialize()
+    {
+#if _GLIBCXX_USE_C99_MATH_TR1
+      if (_M_mean >= 12)
+	{
+	  const double __m = std::floor(_M_mean);
+	  _M_lm_thr = std::log(_M_mean);
+	  _M_lfm = std::lgamma(__m + 1);
+	  _M_sm = std::sqrt(__m);
+
+	  const double __pi_4 = 0.7853981633974483096156608458198757L;
+	  const double __dx = std::sqrt(2 * __m * std::log(32 * __m
+							      / __pi_4));
+	  _M_d = std::round(std::max<double>(6.0, std::min(__m, __dx)));
+	  const double __cx = 2 * __m + _M_d;
+	  _M_scx = std::sqrt(__cx / 2);
+	  _M_1cx = 1 / __cx;
+
+	  _M_c2b = std::sqrt(__pi_4 * __cx) * std::exp(_M_1cx);
+	  _M_cb = 2 * __cx * std::exp(-_M_d * _M_1cx * (1 + _M_d / 2))
+		/ _M_d;
+	}
+      else
+#endif
+	_M_lm_thr = std::exp(-_M_mean);
+      }
+
+  /**
+   * A rejection algorithm when mean >= 12 and a simple method based
+   * upon the multiplication of uniform random variates otherwise.
+   * NB: The former is available only if _GLIBCXX_USE_C99_MATH_TR1
+   * is defined.
+   *
+   * Reference:
+   * Devroye, L. Non-Uniform Random Variates Generation. Springer-Verlag,
+   * New York, 1986, Ch. X, Sects. 3.3 & 3.4 (+ Errata!).
+   */
+  template<typename _IntType>
+    template<typename _UniformRandomNumberGenerator>
+      typename poisson_distribution<_IntType>::result_type
+      poisson_distribution<_IntType>::
+      operator()(_UniformRandomNumberGenerator& __urng,
+		 const param_type& __param)
+      {
+	__detail::_Adaptor<_UniformRandomNumberGenerator, double>
+	  __aurng(__urng);
+#if _GLIBCXX_USE_C99_MATH_TR1
+	if (__param.mean() >= 12)
+	  {
+	    double __x;
+
+	    // See comments above...
+	    const double __naf =
+	      (1 - std::numeric_limits<double>::epsilon()) / 2;
+	    const double __thr =
+	      std::numeric_limits<_IntType>::max() + __naf;
+
+	    const double __m = std::floor(__param.mean());
+	    // sqrt(pi / 2)
+	    const double __spi_2 = 1.2533141373155002512078826424055226L;
+	    const double __c1 = __param._M_sm * __spi_2;
+	    const double __c2 = __param._M_c2b + __c1;
+	    const double __c3 = __c2 + 1;
+	    const double __c4 = __c3 + 1;
+	    // 1 / 78
+	    const double __178 = 0.0128205128205128205128205128205128L;
+	    // e^(1 / 78)
+	    const double __e178 = 1.0129030479320018583185514777512983L;
+	    const double __c5 = __c4 + __e178;
+	    const double __c = __param._M_cb + __c5;
+	    const double __2cx = 2 * (2 * __m + __param._M_d);
+
+	    bool __reject = true;
+	    do
+	      {
+		const double __u = __c * __aurng();
+		const double __e = -std::log(1.0 - __aurng());
+
+		double __w = 0.0;
+
+		if (__u <= __c1)
+		  {
+		    const double __n = _M_nd(__urng);
+		    const double __y = -std::abs(__n) * __param._M_sm - 1;
+		    __x = std::floor(__y);
+		    __w = -__n * __n / 2;
+		    if (__x < -__m)
+		      continue;
+		  }
+		else if (__u <= __c2)
+		  {
+		    const double __n = _M_nd(__urng);
+		    const double __y = 1 + std::abs(__n) * __param._M_scx;
+		    __x = std::ceil(__y);
+		    __w = __y * (2 - __y) * __param._M_1cx;
+		    if (__x > __param._M_d)
+		      continue;
+		  }
+		else if (__u <= __c3)
+		  // NB: This case not in the book, nor in the Errata,
+		  // but should be ok...
+		  __x = -1;
+		else if (__u <= __c4)
+		  __x = 0;
+		else if (__u <= __c5)
+		  {
+		    __x = 1;
+		    // Only in the Errata, see libstdc++/83237.
+		    __w = __178;
+		  }
+		else
+		  {
+		    const double __v = -std::log(1.0 - __aurng());
+		    const double __y = __param._M_d
+				     + __v * __2cx / __param._M_d;
+		    __x = std::ceil(__y);
+		    __w = -__param._M_d * __param._M_1cx * (1 + __y / 2);
+		  }
+
+		__reject = (__w - __e - __x * __param._M_lm_thr
+			    > __param._M_lfm - std::lgamma(__x + __m + 1));
+
+		__reject |= __x + __m >= __thr;
+
+	      } while (__reject);
+
+	    return result_type(__x + __m + __naf);
+	  }
+	else
+#endif
+	  {
+	    _IntType     __x = 0;
+	    double __prod = 1.0;
+
+	    do
+	      {
+		__prod *= __aurng();
+		__x += 1;
+	      }
+	    while (__prod > __param._M_lm_thr);
+
+	    return __x - 1;
+	  }
+      }
+
+  template<typename _IntType>
+    template<typename _ForwardIterator,
+	     typename _UniformRandomNumberGenerator>
+      void
+      poisson_distribution<_IntType>::
+      __generate_impl(_ForwardIterator __f, _ForwardIterator __t,
+		      _UniformRandomNumberGenerator& __urng,
+		      const param_type& __param)
+      {
+	__glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+	// We could duplicate everything from operator()...
+	while (__f != __t)
+	  *__f++ = this->operator()(__urng, __param);
+      }
+
+  template<typename _IntType,
+	   typename _CharT, typename _Traits>
+    std::basic_ostream<_CharT, _Traits>&
+    operator<<(std::basic_ostream<_CharT, _Traits>& __os,
+	       const poisson_distribution<_IntType>& __x)
+    {
+      using __ios_base = typename basic_ostream<_CharT, _Traits>::ios_base;
+
+      const typename __ios_base::fmtflags __flags = __os.flags();
+      const _CharT __fill = __os.fill();
+      const std::streamsize __precision = __os.precision();
+      const _CharT __space = __os.widen(' ');
+      __os.flags(__ios_base::scientific | __ios_base::left);
+      __os.fill(__space);
+      __os.precision(std::numeric_limits<double>::max_digits10);
+
+      __os << __x.mean() << __space << __x._M_nd;
+
+      __os.flags(__flags);
+      __os.fill(__fill);
+      __os.precision(__precision);
+      return __os;
+    }
+
+  template<typename _IntType,
+	   typename _CharT, typename _Traits>
+    std::basic_istream<_CharT, _Traits>&
+    operator>>(std::basic_istream<_CharT, _Traits>& __is,
+	       poisson_distribution<_IntType>& __x)
+    {
+      using param_type = typename poisson_distribution<_IntType>::param_type;
+      using __ios_base = typename basic_istream<_CharT, _Traits>::ios_base;
+
+      const typename __ios_base::fmtflags __flags = __is.flags();
+      __is.flags(__ios_base::skipws);
+
+      double __mean;
+      if (__is >> __mean >> __x._M_nd)
+	__x.param(param_type(__mean));
+
+      __is.flags(__flags);
+      return __is;
+    }
+
+
+  template<typename _IntType>
+    void
+    binomial_distribution<_IntType>::param_type::
+    _M_initialize()
+    {
+      const double __p12 = _M_p <= 0.5 ? _M_p : 1.0 - _M_p;
+
+      _M_easy = true;
+
+#if _GLIBCXX_USE_C99_MATH_TR1
+      if (_M_t * __p12 >= 8)
+	{
+	  _M_easy = false;
+	  const double __np = std::floor(_M_t * __p12);
+	  const double __pa = __np / _M_t;
+	  const double __1p = 1 - __pa;
+
+	  const double __pi_4 = 0.7853981633974483096156608458198757L;
+	  const double __d1x =
+	    std::sqrt(__np * __1p * std::log(32 * __np
+					     / (81 * __pi_4 * __1p)));
+	  _M_d1 = std::round(std::max<double>(1.0, __d1x));
+	  const double __d2x =
+	    std::sqrt(__np * __1p * std::log(32 * _M_t * __1p
+					     / (__pi_4 * __pa)));
+	  _M_d2 = std::round(std::max<double>(1.0, __d2x));
+
+	  // sqrt(pi / 2)
+	  const double __spi_2 = 1.2533141373155002512078826424055226L;
+	  _M_s1 = std::sqrt(__np * __1p) * (1 + _M_d1 / (4 * __np));
+	  _M_s2 = std::sqrt(__np * __1p) * (1 + _M_d2 / (4 * _M_t * __1p));
+	  _M_c = 2 * _M_d1 / __np;
+	  _M_a1 = std::exp(_M_c) * _M_s1 * __spi_2;
+	  const double __a12 = _M_a1 + _M_s2 * __spi_2;
+	  const double __s1s = _M_s1 * _M_s1;
+	  _M_a123 = __a12 + (std::exp(_M_d1 / (_M_t * __1p))
+			     * 2 * __s1s / _M_d1
+			     * std::exp(-_M_d1 * _M_d1 / (2 * __s1s)));
+	  const double __s2s = _M_s2 * _M_s2;
+	  _M_s = (_M_a123 + 2 * __s2s / _M_d2
+		  * std::exp(-_M_d2 * _M_d2 / (2 * __s2s)));
+	  _M_lf = (std::lgamma(__np + 1)
+		   + std::lgamma(_M_t - __np + 1));
+	  _M_lp1p = std::log(__pa / __1p);
+
+	  _M_q = -std::log(1 - (__p12 - __pa) / __1p);
+	}
+      else
+#endif
+	_M_q = -std::log(1 - __p12);
+    }
+
+  template<typename _IntType>
+    template<typename _UniformRandomNumberGenerator>
+      typename binomial_distribution<_IntType>::result_type
+      binomial_distribution<_IntType>::
+      _M_waiting(_UniformRandomNumberGenerator& __urng,
+		 _IntType __t, double __q)
+      {
+	_IntType __x = 0;
+	double __sum = 0.0;
+	__detail::_Adaptor<_UniformRandomNumberGenerator, double>
+	  __aurng(__urng);
+
+	do
+	  {
+	    if (__t == __x)
+	      return __x;
+	    const double __e = -std::log(1.0 - __aurng());
+	    __sum += __e / (__t - __x);
+	    __x += 1;
+	  }
+	while (__sum <= __q);
+
+	return __x - 1;
+      }
+
+  /**
+   * A rejection algorithm when t * p >= 8 and a simple waiting time
+   * method - the second in the referenced book - otherwise.
+   * NB: The former is available only if _GLIBCXX_USE_C99_MATH_TR1
+   * is defined.
+   *
+   * Reference:
+   * Devroye, L. Non-Uniform Random Variates Generation. Springer-Verlag,
+   * New York, 1986, Ch. X, Sect. 4 (+ Errata!).
+   */
+  template<typename _IntType>
+    template<typename _UniformRandomNumberGenerator>
+      typename binomial_distribution<_IntType>::result_type
+      binomial_distribution<_IntType>::
+      operator()(_UniformRandomNumberGenerator& __urng,
+		 const param_type& __param)
+      {
+	result_type __ret;
+	const _IntType __t = __param.t();
+	const double __p = __param.p();
+	const double __p12 = __p <= 0.5 ? __p : 1.0 - __p;
+	__detail::_Adaptor<_UniformRandomNumberGenerator, double>
+	  __aurng(__urng);
+
+#if _GLIBCXX_USE_C99_MATH_TR1
+	if (!__param._M_easy)
+	  {
+	    double __x;
+
+	    // See comments above...
+	    const double __naf =
+	      (1 - std::numeric_limits<double>::epsilon()) / 2;
+	    const double __thr =
+	      std::numeric_limits<_IntType>::max() + __naf;
+
+	    const double __np = std::floor(__t * __p12);
+
+	    // sqrt(pi / 2)
+	    const double __spi_2 = 1.2533141373155002512078826424055226L;
+	    const double __a1 = __param._M_a1;
+	    const double __a12 = __a1 + __param._M_s2 * __spi_2;
+	    const double __a123 = __param._M_a123;
+	    const double __s1s = __param._M_s1 * __param._M_s1;
+	    const double __s2s = __param._M_s2 * __param._M_s2;
+
+	    bool __reject;
+	    do
+	      {
+		const double __u = __param._M_s * __aurng();
+
+		double __v;
+
+		if (__u <= __a1)
+		  {
+		    const double __n = _M_nd(__urng);
+		    const double __y = __param._M_s1 * std::abs(__n);
+		    __reject = __y >= __param._M_d1;
+		    if (!__reject)
+		      {
+			const double __e = -std::log(1.0 - __aurng());
+			__x = std::floor(__y);
+			__v = -__e - __n * __n / 2 + __param._M_c;
+		      }
+		  }
+		else if (__u <= __a12)
+		  {
+		    const double __n = _M_nd(__urng);
+		    const double __y = __param._M_s2 * std::abs(__n);
+		    __reject = __y >= __param._M_d2;
+		    if (!__reject)
+		      {
+			const double __e = -std::log(1.0 - __aurng());
+			__x = std::floor(-__y);
+			__v = -__e - __n * __n / 2;
+		      }
+		  }
+		else if (__u <= __a123)
+		  {
+		    const double __e1 = -std::log(1.0 - __aurng());
+		    const double __e2 = -std::log(1.0 - __aurng());
+
+		    const double __y = __param._M_d1
+				     + 2 * __s1s * __e1 / __param._M_d1;
+		    __x = std::floor(__y);
+		    __v = (-__e2 + __param._M_d1 * (1 / (__t - __np)
+						    -__y / (2 * __s1s)));
+		    __reject = false;
+		  }
+		else
+		  {
+		    const double __e1 = -std::log(1.0 - __aurng());
+		    const double __e2 = -std::log(1.0 - __aurng());
+
+		    const double __y = __param._M_d2
+				     + 2 * __s2s * __e1 / __param._M_d2;
+		    __x = std::floor(-__y);
+		    __v = -__e2 - __param._M_d2 * __y / (2 * __s2s);
+		    __reject = false;
+		  }
+
+		__reject = __reject || __x < -__np || __x > __t - __np;
+		if (!__reject)
+		  {
+		    const double __lfx =
+		      std::lgamma(__np + __x + 1)
+		      + std::lgamma(__t - (__np + __x) + 1);
+		    __reject = __v > __param._M_lf - __lfx
+			     + __x * __param._M_lp1p;
+		  }
+
+		__reject |= __x + __np >= __thr;
+	      }
+	    while (__reject);
+
+	    __x += __np + __naf;
+
+	    const _IntType __z = _M_waiting(__urng, __t - _IntType(__x),
+					    __param._M_q);
+	    __ret = _IntType(__x) + __z;
+	  }
+	else
+#endif
+	  __ret = _M_waiting(__urng, __t, __param._M_q);
+
+	if (__p12 != __p)
+	  __ret = __t - __ret;
+	return __ret;
+      }
+
+  template<typename _IntType>
+    template<typename _ForwardIterator,
+	     typename _UniformRandomNumberGenerator>
+      void
+      binomial_distribution<_IntType>::
+      __generate_impl(_ForwardIterator __f, _ForwardIterator __t,
+		      _UniformRandomNumberGenerator& __urng,
+		      const param_type& __param)
+      {
+	__glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+	// We could duplicate everything from operator()...
+	while (__f != __t)
+	  *__f++ = this->operator()(__urng, __param);
+      }
+
+  template<typename _IntType,
+	   typename _CharT, typename _Traits>
+    std::basic_ostream<_CharT, _Traits>&
+    operator<<(std::basic_ostream<_CharT, _Traits>& __os,
+	       const binomial_distribution<_IntType>& __x)
+    {
+      using __ios_base = typename basic_ostream<_CharT, _Traits>::ios_base;
+
+      const typename __ios_base::fmtflags __flags = __os.flags();
+      const _CharT __fill = __os.fill();
+      const std::streamsize __precision = __os.precision();
+      const _CharT __space = __os.widen(' ');
+      __os.flags(__ios_base::scientific | __ios_base::left);
+      __os.fill(__space);
+      __os.precision(std::numeric_limits<double>::max_digits10);
+
+      __os << __x.t() << __space << __x.p()
+	   << __space << __x._M_nd;
+
+      __os.flags(__flags);
+      __os.fill(__fill);
+      __os.precision(__precision);
+      return __os;
+    }
+
+  template<typename _IntType,
+	   typename _CharT, typename _Traits>
+    std::basic_istream<_CharT, _Traits>&
+    operator>>(std::basic_istream<_CharT, _Traits>& __is,
+	       binomial_distribution<_IntType>& __x)
+    {
+      using param_type = typename binomial_distribution<_IntType>::param_type;
+      using __ios_base = typename basic_istream<_CharT, _Traits>::ios_base;
+
+      const typename __ios_base::fmtflags __flags = __is.flags();
+      __is.flags(__ios_base::dec | __ios_base::skipws);
+
+      _IntType __t;
+      double __p;
+      if (__is >> __t >> __p >> __x._M_nd)
+	__x.param(param_type(__t, __p));
+
+      __is.flags(__flags);
+      return __is;
+    }
+
+
+  template<typename _RealType>
+    template<typename _ForwardIterator,
+	     typename _UniformRandomNumberGenerator>
+      void
+      std::exponential_distribution<_RealType>::
+      __generate_impl(_ForwardIterator __f, _ForwardIterator __t,
+		      _UniformRandomNumberGenerator& __urng,
+		      const param_type& __p)
+      {
+	__glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+	__detail::_Adaptor<_UniformRandomNumberGenerator, result_type>
+	  __aurng(__urng);
+	while (__f != __t)
+	  *__f++ = -std::log(result_type(1) - __aurng()) / __p.lambda();
+      }
+
+  template<typename _RealType, typename _CharT, typename _Traits>
+    std::basic_ostream<_CharT, _Traits>&
+    operator<<(std::basic_ostream<_CharT, _Traits>& __os,
+	       const exponential_distribution<_RealType>& __x)
+    {
+      using __ios_base = typename basic_ostream<_CharT, _Traits>::ios_base;
+
+      const typename __ios_base::fmtflags __flags = __os.flags();
+      const _CharT __fill = __os.fill();
+      const std::streamsize __precision = __os.precision();
+      __os.flags(__ios_base::scientific | __ios_base::left);
+      __os.fill(__os.widen(' '));
+      __os.precision(std::numeric_limits<_RealType>::max_digits10);
+
+      __os << __x.lambda();
+
+      __os.flags(__flags);
+      __os.fill(__fill);
+      __os.precision(__precision);
+      return __os;
+    }
+
+  template<typename _RealType, typename _CharT, typename _Traits>
+    std::basic_istream<_CharT, _Traits>&
+    operator>>(std::basic_istream<_CharT, _Traits>& __is,
+	       exponential_distribution<_RealType>& __x)
+    {
+      using param_type
+	= typename exponential_distribution<_RealType>::param_type;
+      using __ios_base = typename basic_istream<_CharT, _Traits>::ios_base;
+
+      const typename __ios_base::fmtflags __flags = __is.flags();
+      __is.flags(__ios_base::dec | __ios_base::skipws);
+
+      _RealType __lambda;
+      if (__is >> __lambda)
+	__x.param(param_type(__lambda));
+
+      __is.flags(__flags);
+      return __is;
+    }
+
+
+  /**
+   * Polar method due to Marsaglia.
+   *
+   * Devroye, L. Non-Uniform Random Variates Generation. Springer-Verlag,
+   * New York, 1986, Ch. V, Sect. 4.4.
+   */
+  template<typename _RealType>
+    template<typename _UniformRandomNumberGenerator>
+      typename normal_distribution<_RealType>::result_type
+      normal_distribution<_RealType>::
+      operator()(_UniformRandomNumberGenerator& __urng,
+		 const param_type& __param)
+      {
+	result_type __ret;
+	__detail::_Adaptor<_UniformRandomNumberGenerator, result_type>
+	  __aurng(__urng);
+
+	if (_M_saved_available)
+	  {
+	    _M_saved_available = false;
+	    __ret = _M_saved;
+	  }
+	else
+	  {
+	    result_type __x, __y, __r2;
+	    do
+	      {
+		__x = result_type(2.0) * __aurng() - 1.0;
+		__y = result_type(2.0) * __aurng() - 1.0;
+		__r2 = __x * __x + __y * __y;
+	      }
+	    while (__r2 > 1.0 || __r2 == 0.0);
+
+	    const result_type __mult = std::sqrt(-2 * std::log(__r2) / __r2);
+	    _M_saved = __x * __mult;
+	    _M_saved_available = true;
+	    __ret = __y * __mult;
+	  }
+
+	__ret = __ret * __param.stddev() + __param.mean();
+	return __ret;
+      }
+
+  template<typename _RealType>
+    template<typename _ForwardIterator,
+	     typename _UniformRandomNumberGenerator>
+      void
+      normal_distribution<_RealType>::
+      __generate_impl(_ForwardIterator __f, _ForwardIterator __t,
+		      _UniformRandomNumberGenerator& __urng,
+		      const param_type& __param)
+      {
+	__glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+
+	if (__f == __t)
+	  return;
+
+	if (_M_saved_available)
+	  {
+	    _M_saved_available = false;
+	    *__f++ = _M_saved * __param.stddev() + __param.mean();
+
+	    if (__f == __t)
+	      return;
+	  }
+
+	__detail::_Adaptor<_UniformRandomNumberGenerator, result_type>
+	  __aurng(__urng);
+
+	while (__f + 1 < __t)
+	  {
+	    result_type __x, __y, __r2;
+	    do
+	      {
+		__x = result_type(2.0) * __aurng() - 1.0;
+		__y = result_type(2.0) * __aurng() - 1.0;
+		__r2 = __x * __x + __y * __y;
+	      }
+	    while (__r2 > 1.0 || __r2 == 0.0);
+
+	    const result_type __mult = std::sqrt(-2 * std::log(__r2) / __r2);
+	    *__f++ = __y * __mult * __param.stddev() + __param.mean();
+	    *__f++ = __x * __mult * __param.stddev() + __param.mean();
+	  }
+
+	if (__f != __t)
+	  {
+	    result_type __x, __y, __r2;
+	    do
+	      {
+		__x = result_type(2.0) * __aurng() - 1.0;
+		__y = result_type(2.0) * __aurng() - 1.0;
+		__r2 = __x * __x + __y * __y;
+	      }
+	    while (__r2 > 1.0 || __r2 == 0.0);
+
+	    const result_type __mult = std::sqrt(-2 * std::log(__r2) / __r2);
+	    _M_saved = __x * __mult;
+	    _M_saved_available = true;
+	    *__f = __y * __mult * __param.stddev() + __param.mean();
+	  }
+      }
+
+  template<typename _RealType>
+    bool
+    operator==(const std::normal_distribution<_RealType>& __d1,
+	       const std::normal_distribution<_RealType>& __d2)
+    {
+      if (__d1._M_param == __d2._M_param
+	  && __d1._M_saved_available == __d2._M_saved_available)
+	{
+	  if (__d1._M_saved_available
+	      && __d1._M_saved == __d2._M_saved)
+	    return true;
+	  else if(!__d1._M_saved_available)
+	    return true;
+	  else
+	    return false;
+	}
+      else
+	return false;
+    }
+
+  template<typename _RealType, typename _CharT, typename _Traits>
+    std::basic_ostream<_CharT, _Traits>&
+    operator<<(std::basic_ostream<_CharT, _Traits>& __os,
+	       const normal_distribution<_RealType>& __x)
+    {
+      using __ios_base = typename basic_ostream<_CharT, _Traits>::ios_base;
+
+      const typename __ios_base::fmtflags __flags = __os.flags();
+      const _CharT __fill = __os.fill();
+      const std::streamsize __precision = __os.precision();
+      const _CharT __space = __os.widen(' ');
+      __os.flags(__ios_base::scientific | __ios_base::left);
+      __os.fill(__space);
+      __os.precision(std::numeric_limits<_RealType>::max_digits10);
+
+      __os << __x.mean() << __space << __x.stddev()
+	   << __space << __x._M_saved_available;
+      if (__x._M_saved_available)
+	__os << __space << __x._M_saved;
+
+      __os.flags(__flags);
+      __os.fill(__fill);
+      __os.precision(__precision);
+      return __os;
+    }
+
+  template<typename _RealType, typename _CharT, typename _Traits>
+    std::basic_istream<_CharT, _Traits>&
+    operator>>(std::basic_istream<_CharT, _Traits>& __is,
+	       normal_distribution<_RealType>& __x)
+    {
+      using param_type = typename normal_distribution<_RealType>::param_type;
+      using __ios_base = typename basic_istream<_CharT, _Traits>::ios_base;
+
+      const typename __ios_base::fmtflags __flags = __is.flags();
+      __is.flags(__ios_base::dec | __ios_base::skipws);
+
+      double __mean, __stddev;
+      bool __saved_avail;
+      if (__is >> __mean >> __stddev >> __saved_avail)
+	{
+	  if (!__saved_avail || (__is >> __x._M_saved))
+	    {
+	      __x._M_saved_available = __saved_avail;
+	      __x.param(param_type(__mean, __stddev));
+	    }
+	}
+
+      __is.flags(__flags);
+      return __is;
+    }
+
+
+  template<typename _RealType>
+    template<typename _ForwardIterator,
+	     typename _UniformRandomNumberGenerator>
+      void
+      lognormal_distribution<_RealType>::
+      __generate_impl(_ForwardIterator __f, _ForwardIterator __t,
+		      _UniformRandomNumberGenerator& __urng,
+		      const param_type& __p)
+      {
+	__glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+	  while (__f != __t)
+	    *__f++ = std::exp(__p.s() * _M_nd(__urng) + __p.m());
+      }
+
+  template<typename _RealType, typename _CharT, typename _Traits>
+    std::basic_ostream<_CharT, _Traits>&
+    operator<<(std::basic_ostream<_CharT, _Traits>& __os,
+	       const lognormal_distribution<_RealType>& __x)
+    {
+      using __ios_base = typename basic_ostream<_CharT, _Traits>::ios_base;
+
+      const typename __ios_base::fmtflags __flags = __os.flags();
+      const _CharT __fill = __os.fill();
+      const std::streamsize __precision = __os.precision();
+      const _CharT __space = __os.widen(' ');
+      __os.flags(__ios_base::scientific | __ios_base::left);
+      __os.fill(__space);
+      __os.precision(std::numeric_limits<_RealType>::max_digits10);
+
+      __os << __x.m() << __space << __x.s()
+	   << __space << __x._M_nd;
+
+      __os.flags(__flags);
+      __os.fill(__fill);
+      __os.precision(__precision);
+      return __os;
+    }
+
+  template<typename _RealType, typename _CharT, typename _Traits>
+    std::basic_istream<_CharT, _Traits>&
+    operator>>(std::basic_istream<_CharT, _Traits>& __is,
+	       lognormal_distribution<_RealType>& __x)
+    {
+      using param_type
+	= typename lognormal_distribution<_RealType>::param_type;
+      using __ios_base = typename basic_istream<_CharT, _Traits>::ios_base;
+
+      const typename __ios_base::fmtflags __flags = __is.flags();
+      __is.flags(__ios_base::dec | __ios_base::skipws);
+
+      _RealType __m, __s;
+      if (__is >> __m >> __s >> __x._M_nd)
+	__x.param(param_type(__m, __s));
+
+      __is.flags(__flags);
+      return __is;
+    }
+
+  template<typename _RealType>
+    template<typename _ForwardIterator,
+	     typename _UniformRandomNumberGenerator>
+      void
+      std::chi_squared_distribution<_RealType>::
+      __generate_impl(_ForwardIterator __f, _ForwardIterator __t,
+		      _UniformRandomNumberGenerator& __urng)
+      {
+	__glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+	while (__f != __t)
+	  *__f++ = 2 * _M_gd(__urng);
+      }
+
+  template<typename _RealType>
+    template<typename _ForwardIterator,
+	     typename _UniformRandomNumberGenerator>
+      void
+      std::chi_squared_distribution<_RealType>::
+      __generate_impl(_ForwardIterator __f, _ForwardIterator __t,
+		      _UniformRandomNumberGenerator& __urng,
+		      const typename
+		      std::gamma_distribution<result_type>::param_type& __p)
+      {
+	__glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+	while (__f != __t)
+	  *__f++ = 2 * _M_gd(__urng, __p);
+      }
+
+  template<typename _RealType, typename _CharT, typename _Traits>
+    std::basic_ostream<_CharT, _Traits>&
+    operator<<(std::basic_ostream<_CharT, _Traits>& __os,
+	       const chi_squared_distribution<_RealType>& __x)
+    {
+      using __ios_base = typename basic_ostream<_CharT, _Traits>::ios_base;
+
+      const typename __ios_base::fmtflags __flags = __os.flags();
+      const _CharT __fill = __os.fill();
+      const std::streamsize __precision = __os.precision();
+      const _CharT __space = __os.widen(' ');
+      __os.flags(__ios_base::scientific | __ios_base::left);
+      __os.fill(__space);
+      __os.precision(std::numeric_limits<_RealType>::max_digits10);
+
+      __os << __x.n() << __space << __x._M_gd;
+
+      __os.flags(__flags);
+      __os.fill(__fill);
+      __os.precision(__precision);
+      return __os;
+    }
+
+  template<typename _RealType, typename _CharT, typename _Traits>
+    std::basic_istream<_CharT, _Traits>&
+    operator>>(std::basic_istream<_CharT, _Traits>& __is,
+	       chi_squared_distribution<_RealType>& __x)
+    {
+      using param_type
+	= typename chi_squared_distribution<_RealType>::param_type;
+      using __ios_base = typename basic_istream<_CharT, _Traits>::ios_base;
+
+      const typename __ios_base::fmtflags __flags = __is.flags();
+      __is.flags(__ios_base::dec | __ios_base::skipws);
+
+      _RealType __n;
+      if (__is >> __n >> __x._M_gd)
+	__x.param(param_type(__n));
+
+      __is.flags(__flags);
+      return __is;
+    }
+
+
+  template<typename _RealType>
+    template<typename _UniformRandomNumberGenerator>
+      typename cauchy_distribution<_RealType>::result_type
+      cauchy_distribution<_RealType>::
+      operator()(_UniformRandomNumberGenerator& __urng,
+		 const param_type& __p)
+      {
+	__detail::_Adaptor<_UniformRandomNumberGenerator, result_type>
+	  __aurng(__urng);
+	_RealType __u;
+	do
+	  __u = __aurng();
+	while (__u == 0.5);
+
+	const _RealType __pi = 3.1415926535897932384626433832795029L;
+	return __p.a() + __p.b() * std::tan(__pi * __u);
+      }
+
+  template<typename _RealType>
+    template<typename _ForwardIterator,
+	     typename _UniformRandomNumberGenerator>
+      void
+      cauchy_distribution<_RealType>::
+      __generate_impl(_ForwardIterator __f, _ForwardIterator __t,
+		      _UniformRandomNumberGenerator& __urng,
+		      const param_type& __p)
+      {
+	__glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+	const _RealType __pi = 3.1415926535897932384626433832795029L;
+	__detail::_Adaptor<_UniformRandomNumberGenerator, result_type>
+	  __aurng(__urng);
+	while (__f != __t)
+	  {
+	    _RealType __u;
+	    do
+	      __u = __aurng();
+	    while (__u == 0.5);
+
+	    *__f++ = __p.a() + __p.b() * std::tan(__pi * __u);
+	  }
+      }
+
+  template<typename _RealType, typename _CharT, typename _Traits>
+    std::basic_ostream<_CharT, _Traits>&
+    operator<<(std::basic_ostream<_CharT, _Traits>& __os,
+	       const cauchy_distribution<_RealType>& __x)
+    {
+      using __ios_base = typename basic_ostream<_CharT, _Traits>::ios_base;
+
+      const typename __ios_base::fmtflags __flags = __os.flags();
+      const _CharT __fill = __os.fill();
+      const std::streamsize __precision = __os.precision();
+      const _CharT __space = __os.widen(' ');
+      __os.flags(__ios_base::scientific | __ios_base::left);
+      __os.fill(__space);
+      __os.precision(std::numeric_limits<_RealType>::max_digits10);
+
+      __os << __x.a() << __space << __x.b();
+
+      __os.flags(__flags);
+      __os.fill(__fill);
+      __os.precision(__precision);
+      return __os;
+    }
+
+  template<typename _RealType, typename _CharT, typename _Traits>
+    std::basic_istream<_CharT, _Traits>&
+    operator>>(std::basic_istream<_CharT, _Traits>& __is,
+	       cauchy_distribution<_RealType>& __x)
+    {
+      using param_type = typename cauchy_distribution<_RealType>::param_type;
+      using __ios_base = typename basic_istream<_CharT, _Traits>::ios_base;
+
+      const typename __ios_base::fmtflags __flags = __is.flags();
+      __is.flags(__ios_base::dec | __ios_base::skipws);
+
+      _RealType __a, __b;
+      if (__is >> __a >> __b)
+	__x.param(param_type(__a, __b));
+
+      __is.flags(__flags);
+      return __is;
+    }
+
+
+  template<typename _RealType>
+    template<typename _ForwardIterator,
+	     typename _UniformRandomNumberGenerator>
+      void
+      std::fisher_f_distribution<_RealType>::
+      __generate_impl(_ForwardIterator __f, _ForwardIterator __t,
+		      _UniformRandomNumberGenerator& __urng)
+      {
+	__glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+	while (__f != __t)
+	  *__f++ = ((_M_gd_x(__urng) * n()) / (_M_gd_y(__urng) * m()));
+      }
+
+  template<typename _RealType>
+    template<typename _ForwardIterator,
+	     typename _UniformRandomNumberGenerator>
+      void
+      std::fisher_f_distribution<_RealType>::
+      __generate_impl(_ForwardIterator __f, _ForwardIterator __t,
+		      _UniformRandomNumberGenerator& __urng,
+		      const param_type& __p)
+      {
+	__glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+	typedef typename std::gamma_distribution<result_type>::param_type
+	  param_type;
+	param_type __p1(__p.m() / 2);
+	param_type __p2(__p.n() / 2);
+	while (__f != __t)
+	  *__f++ = ((_M_gd_x(__urng, __p1) * n())
+		    / (_M_gd_y(__urng, __p2) * m()));
+      }
+
+  template<typename _RealType, typename _CharT, typename _Traits>
+    std::basic_ostream<_CharT, _Traits>&
+    operator<<(std::basic_ostream<_CharT, _Traits>& __os,
+	       const fisher_f_distribution<_RealType>& __x)
+    {
+      using __ios_base = typename basic_ostream<_CharT, _Traits>::ios_base;
+
+      const typename __ios_base::fmtflags __flags = __os.flags();
+      const _CharT __fill = __os.fill();
+      const std::streamsize __precision = __os.precision();
+      const _CharT __space = __os.widen(' ');
+      __os.flags(__ios_base::scientific | __ios_base::left);
+      __os.fill(__space);
+      __os.precision(std::numeric_limits<_RealType>::max_digits10);
+
+      __os << __x.m() << __space << __x.n()
+	   << __space << __x._M_gd_x << __space << __x._M_gd_y;
+
+      __os.flags(__flags);
+      __os.fill(__fill);
+      __os.precision(__precision);
+      return __os;
+    }
+
+  template<typename _RealType, typename _CharT, typename _Traits>
+    std::basic_istream<_CharT, _Traits>&
+    operator>>(std::basic_istream<_CharT, _Traits>& __is,
+	       fisher_f_distribution<_RealType>& __x)
+    {
+      using param_type
+	= typename fisher_f_distribution<_RealType>::param_type;
+      using __ios_base = typename basic_istream<_CharT, _Traits>::ios_base;
+
+      const typename __ios_base::fmtflags __flags = __is.flags();
+      __is.flags(__ios_base::dec | __ios_base::skipws);
+
+      _RealType __m, __n;
+      if (__is >> __m >> __n >> __x._M_gd_x >> __x._M_gd_y)
+	__x.param(param_type(__m, __n));
+
+      __is.flags(__flags);
+      return __is;
+    }
+
+
+  template<typename _RealType>
+    template<typename _ForwardIterator,
+	     typename _UniformRandomNumberGenerator>
+      void
+      std::student_t_distribution<_RealType>::
+      __generate_impl(_ForwardIterator __f, _ForwardIterator __t,
+		      _UniformRandomNumberGenerator& __urng)
+      {
+	__glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+	while (__f != __t)
+	  *__f++ = _M_nd(__urng) * std::sqrt(n() / _M_gd(__urng));
+      }
+
+  template<typename _RealType>
+    template<typename _ForwardIterator,
+	     typename _UniformRandomNumberGenerator>
+      void
+      std::student_t_distribution<_RealType>::
+      __generate_impl(_ForwardIterator __f, _ForwardIterator __t,
+		      _UniformRandomNumberGenerator& __urng,
+		      const param_type& __p)
+      {
+	__glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+	typename std::gamma_distribution<result_type>::param_type
+	  __p2(__p.n() / 2, 2);
+	while (__f != __t)
+	  *__f++ =  _M_nd(__urng) * std::sqrt(__p.n() / _M_gd(__urng, __p2));
+      }
+
+  template<typename _RealType, typename _CharT, typename _Traits>
+    std::basic_ostream<_CharT, _Traits>&
+    operator<<(std::basic_ostream<_CharT, _Traits>& __os,
+	       const student_t_distribution<_RealType>& __x)
+    {
+      using __ios_base = typename basic_ostream<_CharT, _Traits>::ios_base;
+
+      const typename __ios_base::fmtflags __flags = __os.flags();
+      const _CharT __fill = __os.fill();
+      const std::streamsize __precision = __os.precision();
+      const _CharT __space = __os.widen(' ');
+      __os.flags(__ios_base::scientific | __ios_base::left);
+      __os.fill(__space);
+      __os.precision(std::numeric_limits<_RealType>::max_digits10);
+
+      __os << __x.n() << __space << __x._M_nd << __space << __x._M_gd;
+
+      __os.flags(__flags);
+      __os.fill(__fill);
+      __os.precision(__precision);
+      return __os;
+    }
+
+  template<typename _RealType, typename _CharT, typename _Traits>
+    std::basic_istream<_CharT, _Traits>&
+    operator>>(std::basic_istream<_CharT, _Traits>& __is,
+	       student_t_distribution<_RealType>& __x)
+    {
+      using param_type
+	= typename student_t_distribution<_RealType>::param_type;
+      using __ios_base = typename basic_istream<_CharT, _Traits>::ios_base;
+
+      const typename __ios_base::fmtflags __flags = __is.flags();
+      __is.flags(__ios_base::dec | __ios_base::skipws);
+
+      _RealType __n;
+      if (__is >> __n >> __x._M_nd >> __x._M_gd)
+	__x.param(param_type(__n));
+
+      __is.flags(__flags);
+      return __is;
+    }
+
+
+  template<typename _RealType>
+    void
+    gamma_distribution<_RealType>::param_type::
+    _M_initialize()
+    {
+      _M_malpha = _M_alpha < 1.0 ? _M_alpha + _RealType(1.0) : _M_alpha;
+
+      const _RealType __a1 = _M_malpha - _RealType(1.0) / _RealType(3.0);
+      _M_a2 = _RealType(1.0) / std::sqrt(_RealType(9.0) * __a1);
+    }
+
+  /**
+   * Marsaglia, G. and Tsang, W. W.
+   * "A Simple Method for Generating Gamma Variables"
+   * ACM Transactions on Mathematical Software, 26, 3, 363-372, 2000.
+   */
+  template<typename _RealType>
+    template<typename _UniformRandomNumberGenerator>
+      typename gamma_distribution<_RealType>::result_type
+      gamma_distribution<_RealType>::
+      operator()(_UniformRandomNumberGenerator& __urng,
+		 const param_type& __param)
+      {
+	__detail::_Adaptor<_UniformRandomNumberGenerator, result_type>
+	  __aurng(__urng);
+
+	result_type __u, __v, __n;
+	const result_type __a1 = (__param._M_malpha
+				  - _RealType(1.0) / _RealType(3.0));
+
+	do
+	  {
+	    do
+	      {
+		__n = _M_nd(__urng);
+		__v = result_type(1.0) + __param._M_a2 * __n; 
+	      }
+	    while (__v <= 0.0);
+
+	    __v = __v * __v * __v;
+	    __u = __aurng();
+	  }
+	while (__u > result_type(1.0) - 0.0331 * __n * __n * __n * __n
+	       && (std::log(__u) > (0.5 * __n * __n + __a1
+				    * (1.0 - __v + std::log(__v)))));
+
+	if (__param.alpha() == __param._M_malpha)
+	  return __a1 * __v * __param.beta();
+	else
+	  {
+	    do
+	      __u = __aurng();
+	    while (__u == 0.0);
+	    
+	    return (std::pow(__u, result_type(1.0) / __param.alpha())
+		    * __a1 * __v * __param.beta());
+	  }
+      }
+
+  template<typename _RealType>
+    template<typename _ForwardIterator,
+	     typename _UniformRandomNumberGenerator>
+      void
+      gamma_distribution<_RealType>::
+      __generate_impl(_ForwardIterator __f, _ForwardIterator __t,
+		      _UniformRandomNumberGenerator& __urng,
+		      const param_type& __param)
+      {
+	__glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+	__detail::_Adaptor<_UniformRandomNumberGenerator, result_type>
+	  __aurng(__urng);
+
+	result_type __u, __v, __n;
+	const result_type __a1 = (__param._M_malpha
+				  - _RealType(1.0) / _RealType(3.0));
+
+	if (__param.alpha() == __param._M_malpha)
+	  while (__f != __t)
+	    {
+	      do
+		{
+		  do
+		    {
+		      __n = _M_nd(__urng);
+		      __v = result_type(1.0) + __param._M_a2 * __n;
+		    }
+		  while (__v <= 0.0);
+
+		  __v = __v * __v * __v;
+		  __u = __aurng();
+		}
+	      while (__u > result_type(1.0) - 0.0331 * __n * __n * __n * __n
+		     && (std::log(__u) > (0.5 * __n * __n + __a1
+					  * (1.0 - __v + std::log(__v)))));
+
+	      *__f++ = __a1 * __v * __param.beta();
+	    }
+	else
+	  while (__f != __t)
+	    {
+	      do
+		{
+		  do
+		    {
+		      __n = _M_nd(__urng);
+		      __v = result_type(1.0) + __param._M_a2 * __n;
+		    }
+		  while (__v <= 0.0);
+
+		  __v = __v * __v * __v;
+		  __u = __aurng();
+		}
+	      while (__u > result_type(1.0) - 0.0331 * __n * __n * __n * __n
+		     && (std::log(__u) > (0.5 * __n * __n + __a1
+					  * (1.0 - __v + std::log(__v)))));
+
+	      do
+		__u = __aurng();
+	      while (__u == 0.0);
+
+	      *__f++ = (std::pow(__u, result_type(1.0) / __param.alpha())
+			* __a1 * __v * __param.beta());
+	    }
+      }
+
+  template<typename _RealType, typename _CharT, typename _Traits>
+    std::basic_ostream<_CharT, _Traits>&
+    operator<<(std::basic_ostream<_CharT, _Traits>& __os,
+	       const gamma_distribution<_RealType>& __x)
+    {
+      using __ios_base = typename basic_ostream<_CharT, _Traits>::ios_base;
+
+      const typename __ios_base::fmtflags __flags = __os.flags();
+      const _CharT __fill = __os.fill();
+      const std::streamsize __precision = __os.precision();
+      const _CharT __space = __os.widen(' ');
+      __os.flags(__ios_base::scientific | __ios_base::left);
+      __os.fill(__space);
+      __os.precision(std::numeric_limits<_RealType>::max_digits10);
+
+      __os << __x.alpha() << __space << __x.beta()
+	   << __space << __x._M_nd;
+
+      __os.flags(__flags);
+      __os.fill(__fill);
+      __os.precision(__precision);
+      return __os;
+    }
+
+  template<typename _RealType, typename _CharT, typename _Traits>
+    std::basic_istream<_CharT, _Traits>&
+    operator>>(std::basic_istream<_CharT, _Traits>& __is,
+	       gamma_distribution<_RealType>& __x)
+    {
+      using param_type = typename gamma_distribution<_RealType>::param_type;
+      using __ios_base = typename basic_istream<_CharT, _Traits>::ios_base;
+
+      const typename __ios_base::fmtflags __flags = __is.flags();
+      __is.flags(__ios_base::dec | __ios_base::skipws);
+
+      _RealType __alpha_val, __beta_val;
+      if (__is >> __alpha_val >> __beta_val >> __x._M_nd)
+	__x.param(param_type(__alpha_val, __beta_val));
+
+      __is.flags(__flags);
+      return __is;
+    }
+
+
+  template<typename _RealType>
+    template<typename _UniformRandomNumberGenerator>
+      typename weibull_distribution<_RealType>::result_type
+      weibull_distribution<_RealType>::
+      operator()(_UniformRandomNumberGenerator& __urng,
+		 const param_type& __p)
+      {
+	__detail::_Adaptor<_UniformRandomNumberGenerator, result_type>
+	  __aurng(__urng);
+	return __p.b() * std::pow(-std::log(result_type(1) - __aurng()),
+				  result_type(1) / __p.a());
+      }
+
+  template<typename _RealType>
+    template<typename _ForwardIterator,
+	     typename _UniformRandomNumberGenerator>
+      void
+      weibull_distribution<_RealType>::
+      __generate_impl(_ForwardIterator __f, _ForwardIterator __t,
+		      _UniformRandomNumberGenerator& __urng,
+		      const param_type& __p)
+      {
+	__glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+	__detail::_Adaptor<_UniformRandomNumberGenerator, result_type>
+	  __aurng(__urng);
+	auto __inv_a = result_type(1) / __p.a();
+
+	while (__f != __t)
+	  *__f++ = __p.b() * std::pow(-std::log(result_type(1) - __aurng()),
+				      __inv_a);
+      }
+
+  template<typename _RealType, typename _CharT, typename _Traits>
+    std::basic_ostream<_CharT, _Traits>&
+    operator<<(std::basic_ostream<_CharT, _Traits>& __os,
+	       const weibull_distribution<_RealType>& __x)
+    {
+      using __ios_base = typename basic_ostream<_CharT, _Traits>::ios_base;
+
+      const typename __ios_base::fmtflags __flags = __os.flags();
+      const _CharT __fill = __os.fill();
+      const std::streamsize __precision = __os.precision();
+      const _CharT __space = __os.widen(' ');
+      __os.flags(__ios_base::scientific | __ios_base::left);
+      __os.fill(__space);
+      __os.precision(std::numeric_limits<_RealType>::max_digits10);
+
+      __os << __x.a() << __space << __x.b();
+
+      __os.flags(__flags);
+      __os.fill(__fill);
+      __os.precision(__precision);
+      return __os;
+    }
+
+  template<typename _RealType, typename _CharT, typename _Traits>
+    std::basic_istream<_CharT, _Traits>&
+    operator>>(std::basic_istream<_CharT, _Traits>& __is,
+	       weibull_distribution<_RealType>& __x)
+    {
+      using param_type = typename weibull_distribution<_RealType>::param_type;
+      using __ios_base = typename basic_istream<_CharT, _Traits>::ios_base;
+
+      const typename __ios_base::fmtflags __flags = __is.flags();
+      __is.flags(__ios_base::dec | __ios_base::skipws);
+
+      _RealType __a, __b;
+      if (__is >> __a >> __b)
+	__x.param(param_type(__a, __b));
+
+      __is.flags(__flags);
+      return __is;
+    }
+
+
+  template<typename _RealType>
+    template<typename _UniformRandomNumberGenerator>
+      typename extreme_value_distribution<_RealType>::result_type
+      extreme_value_distribution<_RealType>::
+      operator()(_UniformRandomNumberGenerator& __urng,
+		 const param_type& __p)
+      {
+	__detail::_Adaptor<_UniformRandomNumberGenerator, result_type>
+	  __aurng(__urng);
+	return __p.a() - __p.b() * std::log(-std::log(result_type(1)
+						      - __aurng()));
+      }
+
+  template<typename _RealType>
+    template<typename _ForwardIterator,
+	     typename _UniformRandomNumberGenerator>
+      void
+      extreme_value_distribution<_RealType>::
+      __generate_impl(_ForwardIterator __f, _ForwardIterator __t,
+		      _UniformRandomNumberGenerator& __urng,
+		      const param_type& __p)
+      {
+	__glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+	__detail::_Adaptor<_UniformRandomNumberGenerator, result_type>
+	  __aurng(__urng);
+
+	while (__f != __t)
+	  *__f++ = __p.a() - __p.b() * std::log(-std::log(result_type(1)
+							  - __aurng()));
+      }
+
+  template<typename _RealType, typename _CharT, typename _Traits>
+    std::basic_ostream<_CharT, _Traits>&
+    operator<<(std::basic_ostream<_CharT, _Traits>& __os,
+	       const extreme_value_distribution<_RealType>& __x)
+    {
+      using __ios_base = typename basic_ostream<_CharT, _Traits>::ios_base;
+
+      const typename __ios_base::fmtflags __flags = __os.flags();
+      const _CharT __fill = __os.fill();
+      const std::streamsize __precision = __os.precision();
+      const _CharT __space = __os.widen(' ');
+      __os.flags(__ios_base::scientific | __ios_base::left);
+      __os.fill(__space);
+      __os.precision(std::numeric_limits<_RealType>::max_digits10);
+
+      __os << __x.a() << __space << __x.b();
+
+      __os.flags(__flags);
+      __os.fill(__fill);
+      __os.precision(__precision);
+      return __os;
+    }
+
+  template<typename _RealType, typename _CharT, typename _Traits>
+    std::basic_istream<_CharT, _Traits>&
+    operator>>(std::basic_istream<_CharT, _Traits>& __is,
+	       extreme_value_distribution<_RealType>& __x)
+    {
+      using param_type
+	= typename extreme_value_distribution<_RealType>::param_type;
+      using __ios_base = typename basic_istream<_CharT, _Traits>::ios_base;
+
+      const typename __ios_base::fmtflags __flags = __is.flags();
+      __is.flags(__ios_base::dec | __ios_base::skipws);
+
+      _RealType __a, __b;
+      if (__is >> __a >> __b)
+	__x.param(param_type(__a, __b));
+
+      __is.flags(__flags);
+      return __is;
+    }
+
+
+  template<typename _IntType>
+    void
+    discrete_distribution<_IntType>::param_type::
+    _M_initialize()
+    {
+      if (_M_prob.size() < 2)
+	{
+	  _M_prob.clear();
+	  return;
+	}
+
+      const double __sum = std::accumulate(_M_prob.begin(),
+					   _M_prob.end(), 0.0);
+      __glibcxx_assert(__sum > 0);
+      // Now normalize the probabilites.
+      __detail::__normalize(_M_prob.begin(), _M_prob.end(), _M_prob.begin(),
+			    __sum);
+      // Accumulate partial sums.
+      _M_cp.reserve(_M_prob.size());
+      std::partial_sum(_M_prob.begin(), _M_prob.end(),
+		       std::back_inserter(_M_cp));
+      // Make sure the last cumulative probability is one.
+      _M_cp[_M_cp.size() - 1] = 1.0;
+    }
+
+  template<typename _IntType>
+    template<typename _Func>
+      discrete_distribution<_IntType>::param_type::
+      param_type(size_t __nw, double __xmin, double __xmax, _Func __fw)
+      : _M_prob(), _M_cp()
+      {
+	const size_t __n = __nw == 0 ? 1 : __nw;
+	const double __delta = (__xmax - __xmin) / __n;
+
+	_M_prob.reserve(__n);
+	for (size_t __k = 0; __k < __nw; ++__k)
+	  _M_prob.push_back(__fw(__xmin + __k * __delta + 0.5 * __delta));
+
+	_M_initialize();
+      }
+
+  template<typename _IntType>
+    template<typename _UniformRandomNumberGenerator>
+      typename discrete_distribution<_IntType>::result_type
+      discrete_distribution<_IntType>::
+      operator()(_UniformRandomNumberGenerator& __urng,
+		 const param_type& __param)
+      {
+	if (__param._M_cp.empty())
+	  return result_type(0);
+
+	__detail::_Adaptor<_UniformRandomNumberGenerator, double>
+	  __aurng(__urng);
+
+	const double __p = __aurng();
+	auto __pos = std::lower_bound(__param._M_cp.begin(),
+				      __param._M_cp.end(), __p);
+
+	return __pos - __param._M_cp.begin();
+      }
+
+  template<typename _IntType>
+    template<typename _ForwardIterator,
+	     typename _UniformRandomNumberGenerator>
+      void
+      discrete_distribution<_IntType>::
+      __generate_impl(_ForwardIterator __f, _ForwardIterator __t,
+		      _UniformRandomNumberGenerator& __urng,
+		      const param_type& __param)
+      {
+	__glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+
+	if (__param._M_cp.empty())
+	  {
+	    while (__f != __t)
+	      *__f++ = result_type(0);
+	    return;
+	  }
+
+	__detail::_Adaptor<_UniformRandomNumberGenerator, double>
+	  __aurng(__urng);
+
+	while (__f != __t)
+	  {
+	    const double __p = __aurng();
+	    auto __pos = std::lower_bound(__param._M_cp.begin(),
+					  __param._M_cp.end(), __p);
+
+	    *__f++ = __pos - __param._M_cp.begin();
+	  }
+      }
+
+  template<typename _IntType, typename _CharT, typename _Traits>
+    std::basic_ostream<_CharT, _Traits>&
+    operator<<(std::basic_ostream<_CharT, _Traits>& __os,
+	       const discrete_distribution<_IntType>& __x)
+    {
+      using __ios_base = typename basic_ostream<_CharT, _Traits>::ios_base;
+
+      const typename __ios_base::fmtflags __flags = __os.flags();
+      const _CharT __fill = __os.fill();
+      const std::streamsize __precision = __os.precision();
+      const _CharT __space = __os.widen(' ');
+      __os.flags(__ios_base::scientific | __ios_base::left);
+      __os.fill(__space);
+      __os.precision(std::numeric_limits<double>::max_digits10);
+
+      std::vector<double> __prob = __x.probabilities();
+      __os << __prob.size();
+      for (auto __dit = __prob.begin(); __dit != __prob.end(); ++__dit)
+	__os << __space << *__dit;
+
+      __os.flags(__flags);
+      __os.fill(__fill);
+      __os.precision(__precision);
+      return __os;
+    }
+
+namespace __detail
+{
+  template<typename _ValT, typename _CharT, typename _Traits>
+    basic_istream<_CharT, _Traits>&
+    __extract_params(basic_istream<_CharT, _Traits>& __is,
+		     vector<_ValT>& __vals, size_t __n)
+    {
+      __vals.reserve(__n);
+      while (__n--)
+	{
+	  _ValT __val;
+	  if (__is >> __val)
+	    __vals.push_back(__val);
+	  else
+	    break;
+	}
+      return __is;
+    }
+} // namespace __detail
+
+  template<typename _IntType, typename _CharT, typename _Traits>
+    std::basic_istream<_CharT, _Traits>&
+    operator>>(std::basic_istream<_CharT, _Traits>& __is,
+	       discrete_distribution<_IntType>& __x)
+    {
+      using __ios_base = typename basic_istream<_CharT, _Traits>::ios_base;
+
+      const typename __ios_base::fmtflags __flags = __is.flags();
+      __is.flags(__ios_base::dec | __ios_base::skipws);
+
+      size_t __n;
+      if (__is >> __n)
+	{
+	  std::vector<double> __prob_vec;
+	  if (__detail::__extract_params(__is, __prob_vec, __n))
+	    __x.param({__prob_vec.begin(), __prob_vec.end()});
+	}
+
+      __is.flags(__flags);
+      return __is;
+    }
+
+
+  template<typename _RealType>
+    void
+    piecewise_constant_distribution<_RealType>::param_type::
+    _M_initialize()
+    {
+      if (_M_int.size() < 2
+	  || (_M_int.size() == 2
+	      && _M_int[0] == _RealType(0)
+	      && _M_int[1] == _RealType(1)))
+	{
+	  _M_int.clear();
+	  _M_den.clear();
+	  return;
+	}
+
+      const double __sum = std::accumulate(_M_den.begin(),
+					   _M_den.end(), 0.0);
+      __glibcxx_assert(__sum > 0);
+
+      __detail::__normalize(_M_den.begin(), _M_den.end(), _M_den.begin(),
+			    __sum);
+
+      _M_cp.reserve(_M_den.size());
+      std::partial_sum(_M_den.begin(), _M_den.end(),
+		       std::back_inserter(_M_cp));
+
+      // Make sure the last cumulative probability is one.
+      _M_cp[_M_cp.size() - 1] = 1.0;
+
+      for (size_t __k = 0; __k < _M_den.size(); ++__k)
+	_M_den[__k] /= _M_int[__k + 1] - _M_int[__k];
+    }
+
+  template<typename _RealType>
+    template<typename _InputIteratorB, typename _InputIteratorW>
+      piecewise_constant_distribution<_RealType>::param_type::
+      param_type(_InputIteratorB __bbegin,
+		 _InputIteratorB __bend,
+		 _InputIteratorW __wbegin)
+      : _M_int(), _M_den(), _M_cp()
+      {
+	if (__bbegin != __bend)
+	  {
+	    for (;;)
+	      {
+		_M_int.push_back(*__bbegin);
+		++__bbegin;
+		if (__bbegin == __bend)
+		  break;
+
+		_M_den.push_back(*__wbegin);
+		++__wbegin;
+	      }
+	  }
+
+	_M_initialize();
+      }
+
+  template<typename _RealType>
+    template<typename _Func>
+      piecewise_constant_distribution<_RealType>::param_type::
+      param_type(initializer_list<_RealType> __bl, _Func __fw)
+      : _M_int(), _M_den(), _M_cp()
+      {
+	_M_int.reserve(__bl.size());
+	for (auto __biter = __bl.begin(); __biter != __bl.end(); ++__biter)
+	  _M_int.push_back(*__biter);
+
+	_M_den.reserve(_M_int.size() - 1);
+	for (size_t __k = 0; __k < _M_int.size() - 1; ++__k)
+	  _M_den.push_back(__fw(0.5 * (_M_int[__k + 1] + _M_int[__k])));
+
+	_M_initialize();
+      }
+
+  template<typename _RealType>
+    template<typename _Func>
+      piecewise_constant_distribution<_RealType>::param_type::
+      param_type(size_t __nw, _RealType __xmin, _RealType __xmax, _Func __fw)
+      : _M_int(), _M_den(), _M_cp()
+      {
+	const size_t __n = __nw == 0 ? 1 : __nw;
+	const _RealType __delta = (__xmax - __xmin) / __n;
+
+	_M_int.reserve(__n + 1);
+	for (size_t __k = 0; __k <= __nw; ++__k)
+	  _M_int.push_back(__xmin + __k * __delta);
+
+	_M_den.reserve(__n);
+	for (size_t __k = 0; __k < __nw; ++__k)
+	  _M_den.push_back(__fw(_M_int[__k] + 0.5 * __delta));
+
+	_M_initialize();
+      }
+
+  template<typename _RealType>
+    template<typename _UniformRandomNumberGenerator>
+      typename piecewise_constant_distribution<_RealType>::result_type
+      piecewise_constant_distribution<_RealType>::
+      operator()(_UniformRandomNumberGenerator& __urng,
+		 const param_type& __param)
+      {
+	__detail::_Adaptor<_UniformRandomNumberGenerator, double>
+	  __aurng(__urng);
+
+	const double __p = __aurng();
+	if (__param._M_cp.empty())
+	  return __p;
+
+	auto __pos = std::lower_bound(__param._M_cp.begin(),
+				      __param._M_cp.end(), __p);
+	const size_t __i = __pos - __param._M_cp.begin();
+
+	const double __pref = __i > 0 ? __param._M_cp[__i - 1] : 0.0;
+
+	return __param._M_int[__i] + (__p - __pref) / __param._M_den[__i];
+      }
+
+  template<typename _RealType>
+    template<typename _ForwardIterator,
+	     typename _UniformRandomNumberGenerator>
+      void
+      piecewise_constant_distribution<_RealType>::
+      __generate_impl(_ForwardIterator __f, _ForwardIterator __t,
+		      _UniformRandomNumberGenerator& __urng,
+		      const param_type& __param)
+      {
+	__glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+	__detail::_Adaptor<_UniformRandomNumberGenerator, double>
+	  __aurng(__urng);
+
+	if (__param._M_cp.empty())
+	  {
+	    while (__f != __t)
+	      *__f++ = __aurng();
+	    return;
+	  }
+
+	while (__f != __t)
+	  {
+	    const double __p = __aurng();
+
+	    auto __pos = std::lower_bound(__param._M_cp.begin(),
+					  __param._M_cp.end(), __p);
+	    const size_t __i = __pos - __param._M_cp.begin();
+
+	    const double __pref = __i > 0 ? __param._M_cp[__i - 1] : 0.0;
+
+	    *__f++ = (__param._M_int[__i]
+		      + (__p - __pref) / __param._M_den[__i]);
+	  }
+      }
+
+  template<typename _RealType, typename _CharT, typename _Traits>
+    std::basic_ostream<_CharT, _Traits>&
+    operator<<(std::basic_ostream<_CharT, _Traits>& __os,
+	       const piecewise_constant_distribution<_RealType>& __x)
+    {
+      using __ios_base = typename basic_ostream<_CharT, _Traits>::ios_base;
+
+      const typename __ios_base::fmtflags __flags = __os.flags();
+      const _CharT __fill = __os.fill();
+      const std::streamsize __precision = __os.precision();
+      const _CharT __space = __os.widen(' ');
+      __os.flags(__ios_base::scientific | __ios_base::left);
+      __os.fill(__space);
+      __os.precision(std::numeric_limits<_RealType>::max_digits10);
+
+      std::vector<_RealType> __int = __x.intervals();
+      __os << __int.size() - 1;
+
+      for (auto __xit = __int.begin(); __xit != __int.end(); ++__xit)
+	__os << __space << *__xit;
+
+      std::vector<double> __den = __x.densities();
+      for (auto __dit = __den.begin(); __dit != __den.end(); ++__dit)
+	__os << __space << *__dit;
+
+      __os.flags(__flags);
+      __os.fill(__fill);
+      __os.precision(__precision);
+      return __os;
+    }
+
+  template<typename _RealType, typename _CharT, typename _Traits>
+    std::basic_istream<_CharT, _Traits>&
+    operator>>(std::basic_istream<_CharT, _Traits>& __is,
+	       piecewise_constant_distribution<_RealType>& __x)
+    {
+      using __ios_base = typename basic_istream<_CharT, _Traits>::ios_base;
+
+      const typename __ios_base::fmtflags __flags = __is.flags();
+      __is.flags(__ios_base::dec | __ios_base::skipws);
+
+      size_t __n;
+      if (__is >> __n)
+	{
+	  std::vector<_RealType> __int_vec;
+	  if (__detail::__extract_params(__is, __int_vec, __n + 1))
+	    {
+	      std::vector<double> __den_vec;
+	      if (__detail::__extract_params(__is, __den_vec, __n))
+		{
+		  __x.param({ __int_vec.begin(), __int_vec.end(),
+			      __den_vec.begin() });
+		}
+	    }
+	}
+
+      __is.flags(__flags);
+      return __is;
+    }
+
+
+  template<typename _RealType>
+    void
+    piecewise_linear_distribution<_RealType>::param_type::
+    _M_initialize()
+    {
+      if (_M_int.size() < 2
+	  || (_M_int.size() == 2
+	      && _M_int[0] == _RealType(0)
+	      && _M_int[1] == _RealType(1)
+	      && _M_den[0] == _M_den[1]))
+	{
+	  _M_int.clear();
+	  _M_den.clear();
+	  return;
+	}
+
+      double __sum = 0.0;
+      _M_cp.reserve(_M_int.size() - 1);
+      _M_m.reserve(_M_int.size() - 1);
+      for (size_t __k = 0; __k < _M_int.size() - 1; ++__k)
+	{
+	  const _RealType __delta = _M_int[__k + 1] - _M_int[__k];
+	  __sum += 0.5 * (_M_den[__k + 1] + _M_den[__k]) * __delta;
+	  _M_cp.push_back(__sum);
+	  _M_m.push_back((_M_den[__k + 1] - _M_den[__k]) / __delta);
+	}
+      __glibcxx_assert(__sum > 0);
+
+      //  Now normalize the densities...
+      __detail::__normalize(_M_den.begin(), _M_den.end(), _M_den.begin(),
+			    __sum);
+      //  ... and partial sums... 
+      __detail::__normalize(_M_cp.begin(), _M_cp.end(), _M_cp.begin(), __sum);
+      //  ... and slopes.
+      __detail::__normalize(_M_m.begin(), _M_m.end(), _M_m.begin(), __sum);
+
+      //  Make sure the last cumulative probablility is one.
+      _M_cp[_M_cp.size() - 1] = 1.0;
+     }
+
+  template<typename _RealType>
+    template<typename _InputIteratorB, typename _InputIteratorW>
+      piecewise_linear_distribution<_RealType>::param_type::
+      param_type(_InputIteratorB __bbegin,
+		 _InputIteratorB __bend,
+		 _InputIteratorW __wbegin)
+      : _M_int(), _M_den(), _M_cp(), _M_m()
+      {
+	for (; __bbegin != __bend; ++__bbegin, ++__wbegin)
+	  {
+	    _M_int.push_back(*__bbegin);
+	    _M_den.push_back(*__wbegin);
+	  }
+
+	_M_initialize();
+      }
+
+  template<typename _RealType>
+    template<typename _Func>
+      piecewise_linear_distribution<_RealType>::param_type::
+      param_type(initializer_list<_RealType> __bl, _Func __fw)
+      : _M_int(), _M_den(), _M_cp(), _M_m()
+      {
+	_M_int.reserve(__bl.size());
+	_M_den.reserve(__bl.size());
+	for (auto __biter = __bl.begin(); __biter != __bl.end(); ++__biter)
+	  {
+	    _M_int.push_back(*__biter);
+	    _M_den.push_back(__fw(*__biter));
+	  }
+
+	_M_initialize();
+      }
+
+  template<typename _RealType>
+    template<typename _Func>
+      piecewise_linear_distribution<_RealType>::param_type::
+      param_type(size_t __nw, _RealType __xmin, _RealType __xmax, _Func __fw)
+      : _M_int(), _M_den(), _M_cp(), _M_m()
+      {
+	const size_t __n = __nw == 0 ? 1 : __nw;
+	const _RealType __delta = (__xmax - __xmin) / __n;
+
+	_M_int.reserve(__n + 1);
+	_M_den.reserve(__n + 1);
+	for (size_t __k = 0; __k <= __nw; ++__k)
+	  {
+	    _M_int.push_back(__xmin + __k * __delta);
+	    _M_den.push_back(__fw(_M_int[__k] + __delta));
+	  }
+
+	_M_initialize();
+      }
+
+  template<typename _RealType>
+    template<typename _UniformRandomNumberGenerator>
+      typename piecewise_linear_distribution<_RealType>::result_type
+      piecewise_linear_distribution<_RealType>::
+      operator()(_UniformRandomNumberGenerator& __urng,
+		 const param_type& __param)
+      {
+	__detail::_Adaptor<_UniformRandomNumberGenerator, double>
+	  __aurng(__urng);
+
+	const double __p = __aurng();
+	if (__param._M_cp.empty())
+	  return __p;
+
+	auto __pos = std::lower_bound(__param._M_cp.begin(),
+				      __param._M_cp.end(), __p);
+	const size_t __i = __pos - __param._M_cp.begin();
+
+	const double __pref = __i > 0 ? __param._M_cp[__i - 1] : 0.0;
+
+	const double __a = 0.5 * __param._M_m[__i];
+	const double __b = __param._M_den[__i];
+	const double __cm = __p - __pref;
+
+	_RealType __x = __param._M_int[__i];
+	if (__a == 0)
+	  __x += __cm / __b;
+	else
+	  {
+	    const double __d = __b * __b + 4.0 * __a * __cm;
+	    __x += 0.5 * (std::sqrt(__d) - __b) / __a;
+          }
+
+        return __x;
+      }
+
+  template<typename _RealType>
+    template<typename _ForwardIterator,
+	     typename _UniformRandomNumberGenerator>
+      void
+      piecewise_linear_distribution<_RealType>::
+      __generate_impl(_ForwardIterator __f, _ForwardIterator __t,
+		      _UniformRandomNumberGenerator& __urng,
+		      const param_type& __param)
+      {
+	__glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+	// We could duplicate everything from operator()...
+	while (__f != __t)
+	  *__f++ = this->operator()(__urng, __param);
+      }
+
+  template<typename _RealType, typename _CharT, typename _Traits>
+    std::basic_ostream<_CharT, _Traits>&
+    operator<<(std::basic_ostream<_CharT, _Traits>& __os,
+	       const piecewise_linear_distribution<_RealType>& __x)
+    {
+      using __ios_base = typename basic_ostream<_CharT, _Traits>::ios_base;
+
+      const typename __ios_base::fmtflags __flags = __os.flags();
+      const _CharT __fill = __os.fill();
+      const std::streamsize __precision = __os.precision();
+      const _CharT __space = __os.widen(' ');
+      __os.flags(__ios_base::scientific | __ios_base::left);
+      __os.fill(__space);
+      __os.precision(std::numeric_limits<_RealType>::max_digits10);
+
+      std::vector<_RealType> __int = __x.intervals();
+      __os << __int.size() - 1;
+
+      for (auto __xit = __int.begin(); __xit != __int.end(); ++__xit)
+	__os << __space << *__xit;
+
+      std::vector<double> __den = __x.densities();
+      for (auto __dit = __den.begin(); __dit != __den.end(); ++__dit)
+	__os << __space << *__dit;
+
+      __os.flags(__flags);
+      __os.fill(__fill);
+      __os.precision(__precision);
+      return __os;
+    }
+
+  template<typename _RealType, typename _CharT, typename _Traits>
+    std::basic_istream<_CharT, _Traits>&
+    operator>>(std::basic_istream<_CharT, _Traits>& __is,
+	       piecewise_linear_distribution<_RealType>& __x)
+    {
+      using __ios_base = typename basic_istream<_CharT, _Traits>::ios_base;
+
+      const typename __ios_base::fmtflags __flags = __is.flags();
+      __is.flags(__ios_base::dec | __ios_base::skipws);
+
+      size_t __n;
+      if (__is >> __n)
+	{
+	  vector<_RealType> __int_vec;
+	  if (__detail::__extract_params(__is, __int_vec, __n + 1))
+	    {
+	      vector<double> __den_vec;
+	      if (__detail::__extract_params(__is, __den_vec, __n + 1))
+		{
+		  __x.param({ __int_vec.begin(), __int_vec.end(),
+			      __den_vec.begin() });
+		}
+	    }
+	}
+      __is.flags(__flags);
+      return __is;
+    }
+
+
+  template<typename _IntType, typename>
+    seed_seq::seed_seq(std::initializer_list<_IntType> __il)
+    {
+      _M_v.reserve(__il.size());
+      for (auto __iter = __il.begin(); __iter != __il.end(); ++__iter)
+	_M_v.push_back(__detail::__mod<result_type,
+		       __detail::_Shift<result_type, 32>::__value>(*__iter));
+    }
+
+  template<typename _InputIterator>
+    seed_seq::seed_seq(_InputIterator __begin, _InputIterator __end)
+    {
+      if _GLIBCXX17_CONSTEXPR (__is_random_access_iter<_InputIterator>::value)
+	_M_v.reserve(std::distance(__begin, __end));
+
+      for (_InputIterator __iter = __begin; __iter != __end; ++__iter)
+	_M_v.push_back(__detail::__mod<result_type,
+		       __detail::_Shift<result_type, 32>::__value>(*__iter));
+    }
+
+  template<typename _RandomAccessIterator>
+    void
+    seed_seq::generate(_RandomAccessIterator __begin,
+		       _RandomAccessIterator __end)
+    {
+      typedef typename iterator_traits<_RandomAccessIterator>::value_type
+        _Type;
+
+      if (__begin == __end)
+	return;
+
+      std::fill(__begin, __end, _Type(0x8b8b8b8bu));
+
+      const size_t __n = __end - __begin;
+      const size_t __s = _M_v.size();
+      const size_t __t = (__n >= 623) ? 11
+		       : (__n >=  68) ? 7
+		       : (__n >=  39) ? 5
+		       : (__n >=   7) ? 3
+		       : (__n - 1) / 2;
+      const size_t __p = (__n - __t) / 2;
+      const size_t __q = __p + __t;
+      const size_t __m = std::max(size_t(__s + 1), __n);
+
+#ifndef __UINT32_TYPE__
+      struct _Up
+      {
+	_Up(uint_least32_t v) : _M_v(v & 0xffffffffu) { }
+
+	operator uint_least32_t() const { return _M_v; }
+
+	uint_least32_t _M_v;
+      };
+      using uint32_t = _Up;
+#endif
+
+      // k == 0, every element in [begin,end) equals 0x8b8b8b8bu
+	{
+	  uint32_t __r1 = 1371501266u;
+	  uint32_t __r2 = __r1 + __s;
+	  __begin[__p] += __r1;
+	  __begin[__q] = (uint32_t)__begin[__q] + __r2;
+	  __begin[0] = __r2;
+	}
+
+      for (size_t __k = 1; __k <= __s; ++__k)
+	{
+	  const size_t __kn = __k % __n;
+	  const size_t __kpn = (__k + __p) % __n;
+	  const size_t __kqn = (__k + __q) % __n;
+	  uint32_t __arg = (__begin[__kn]
+			    ^ __begin[__kpn]
+			    ^ __begin[(__k - 1) % __n]);
+	  uint32_t __r1 = 1664525u * (__arg ^ (__arg >> 27));
+	  uint32_t __r2 = __r1 + (uint32_t)__kn + _M_v[__k - 1];
+	  __begin[__kpn] = (uint32_t)__begin[__kpn] + __r1;
+	  __begin[__kqn] = (uint32_t)__begin[__kqn] + __r2;
+	  __begin[__kn] = __r2;
+	}
+
+      for (size_t __k = __s + 1; __k < __m; ++__k)
+	{
+	  const size_t __kn = __k % __n;
+	  const size_t __kpn = (__k + __p) % __n;
+	  const size_t __kqn = (__k + __q) % __n;
+	  uint32_t __arg = (__begin[__kn]
+				 ^ __begin[__kpn]
+				 ^ __begin[(__k - 1) % __n]);
+	  uint32_t __r1 = 1664525u * (__arg ^ (__arg >> 27));
+	  uint32_t __r2 = __r1 + (uint32_t)__kn;
+	  __begin[__kpn] = (uint32_t)__begin[__kpn] + __r1;
+	  __begin[__kqn] = (uint32_t)__begin[__kqn] + __r2;
+	  __begin[__kn] = __r2;
+	}
+
+      for (size_t __k = __m; __k < __m + __n; ++__k)
+	{
+	  const size_t __kn = __k % __n;
+	  const size_t __kpn = (__k + __p) % __n;
+	  const size_t __kqn = (__k + __q) % __n;
+	  uint32_t __arg = (__begin[__kn]
+			    + __begin[__kpn]
+			    + __begin[(__k - 1) % __n]);
+	  uint32_t __r3 = 1566083941u * (__arg ^ (__arg >> 27));
+	  uint32_t __r4 = __r3 - __kn;
+	  __begin[__kpn] ^= __r3;
+	  __begin[__kqn] ^= __r4;
+	  __begin[__kn] = __r4;
+	}
+    }
+
+  template<typename _RealType, size_t __bits,
+	   typename _UniformRandomNumberGenerator>
+    _RealType
+    generate_canonical(_UniformRandomNumberGenerator& __urng)
+    {
+      static_assert(std::is_floating_point<_RealType>::value,
+		    "template argument must be a floating point type");
+
+      const size_t __b
+	= std::min(static_cast<size_t>(std::numeric_limits<_RealType>::digits),
+                   __bits);
+      const long double __r = static_cast<long double>(__urng.max())
+			    - static_cast<long double>(__urng.min()) + 1.0L;
+      const size_t __log2r = std::log(__r) / std::log(2.0L);
+      const size_t __m = std::max<size_t>(1UL,
+					  (__b + __log2r - 1UL) / __log2r);
+      _RealType __ret;
+      _RealType __sum = _RealType(0);
+      _RealType __tmp = _RealType(1);
+      for (size_t __k = __m; __k != 0; --__k)
+	{
+	  __sum += _RealType(__urng() - __urng.min()) * __tmp;
+	  __tmp *= __r;
+	}
+      __ret = __sum / __tmp;
+      if (__builtin_expect(__ret >= _RealType(1), 0))
+	{
+#if _GLIBCXX_USE_C99_MATH_TR1
+	  __ret = std::nextafter(_RealType(1), _RealType(0));
+#else
+	  __ret = _RealType(1)
+	    - std::numeric_limits<_RealType>::epsilon() / _RealType(2);
+#endif
+	}
+      return __ret;
+    }
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@range_access.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@range_access.h
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@range_access.h
@@ -0,0 +1,371 @@
+// Range access functions for containers -*- C++ -*-
+
+// Copyright (C) 2010-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/range_access.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{iterator}
+ */
+
+#ifndef _GLIBCXX_RANGE_ACCESS_H
+#define _GLIBCXX_RANGE_ACCESS_H 1
+
+#pragma GCC system_header
+
+#if __cplusplus >= 201103L
+#include <initializer_list>
+#include <type_traits>	    // common_type_t, make_signed_t
+#include <bits/stl_iterator.h> // reverse_iterator
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /**
+   *  @brief  Return an iterator pointing to the first element of
+   *          the container.
+   *  @param  __cont  Container.
+   */
+  template<typename _Container>
+    [[__nodiscard__]]
+    inline _GLIBCXX17_CONSTEXPR auto
+    begin(_Container& __cont) -> decltype(__cont.begin())
+    { return __cont.begin(); }
+
+  /**
+   *  @brief  Return an iterator pointing to the first element of
+   *          the const container.
+   *  @param  __cont  Container.
+   */
+  template<typename _Container>
+    [[__nodiscard__]]
+    inline _GLIBCXX17_CONSTEXPR auto
+    begin(const _Container& __cont) -> decltype(__cont.begin())
+    { return __cont.begin(); }
+
+  /**
+   *  @brief  Return an iterator pointing to one past the last element of
+   *          the container.
+   *  @param  __cont  Container.
+   */
+  template<typename _Container>
+    [[__nodiscard__]]
+    inline _GLIBCXX17_CONSTEXPR auto
+    end(_Container& __cont) -> decltype(__cont.end())
+    { return __cont.end(); }
+
+  /**
+   *  @brief  Return an iterator pointing to one past the last element of
+   *          the const container.
+   *  @param  __cont  Container.
+   */
+  template<typename _Container>
+    [[__nodiscard__]]
+    inline _GLIBCXX17_CONSTEXPR auto
+    end(const _Container& __cont) -> decltype(__cont.end())
+    { return __cont.end(); }
+
+  /**
+   *  @brief  Return an iterator pointing to the first element of the array.
+   *  @param  __arr  Array.
+   */
+  template<typename _Tp, size_t _Nm>
+    [[__nodiscard__]]
+    inline _GLIBCXX14_CONSTEXPR _Tp*
+    begin(_Tp (&__arr)[_Nm]) noexcept
+    { return __arr; }
+
+  /**
+   *  @brief  Return an iterator pointing to one past the last element
+   *          of the array.
+   *  @param  __arr  Array.
+   */
+  template<typename _Tp, size_t _Nm>
+    [[__nodiscard__]]
+    inline _GLIBCXX14_CONSTEXPR _Tp*
+    end(_Tp (&__arr)[_Nm]) noexcept
+    { return __arr + _Nm; }
+
+#if __cplusplus >= 201402L
+
+  template<typename _Tp> class valarray;
+  // These overloads must be declared for cbegin and cend to use them.
+  template<typename _Tp> _Tp* begin(valarray<_Tp>&) noexcept;
+  template<typename _Tp> const _Tp* begin(const valarray<_Tp>&) noexcept;
+  template<typename _Tp> _Tp* end(valarray<_Tp>&) noexcept;
+  template<typename _Tp> const _Tp* end(const valarray<_Tp>&) noexcept;
+
+  /**
+   *  @brief  Return an iterator pointing to the first element of
+   *          the const container.
+   *  @param  __cont  Container.
+   */
+  template<typename _Container>
+    [[__nodiscard__]]
+    constexpr auto
+    cbegin(const _Container& __cont) noexcept(noexcept(std::begin(__cont)))
+      -> decltype(std::begin(__cont))
+    { return std::begin(__cont); }
+
+  /**
+   *  @brief  Return an iterator pointing to one past the last element of
+   *          the const container.
+   *  @param  __cont  Container.
+   */
+  template<typename _Container>
+    [[__nodiscard__]]
+    constexpr auto
+    cend(const _Container& __cont) noexcept(noexcept(std::end(__cont)))
+      -> decltype(std::end(__cont))
+    { return std::end(__cont); }
+
+  /**
+   *  @brief  Return a reverse iterator pointing to the last element of
+   *          the container.
+   *  @param  __cont  Container.
+   */
+  template<typename _Container>
+    [[__nodiscard__]]
+    inline _GLIBCXX17_CONSTEXPR auto
+    rbegin(_Container& __cont) -> decltype(__cont.rbegin())
+    { return __cont.rbegin(); }
+
+  /**
+   *  @brief  Return a reverse iterator pointing to the last element of
+   *          the const container.
+   *  @param  __cont  Container.
+   */
+  template<typename _Container>
+    [[__nodiscard__]]
+    inline _GLIBCXX17_CONSTEXPR auto
+    rbegin(const _Container& __cont) -> decltype(__cont.rbegin())
+    { return __cont.rbegin(); }
+
+  /**
+   *  @brief  Return a reverse iterator pointing one past the first element of
+   *          the container.
+   *  @param  __cont  Container.
+   */
+  template<typename _Container>
+    [[__nodiscard__]]
+    inline _GLIBCXX17_CONSTEXPR auto
+    rend(_Container& __cont) -> decltype(__cont.rend())
+    { return __cont.rend(); }
+
+  /**
+   *  @brief  Return a reverse iterator pointing one past the first element of
+   *          the const container.
+   *  @param  __cont  Container.
+   */
+  template<typename _Container>
+    [[__nodiscard__]]
+    inline _GLIBCXX17_CONSTEXPR auto
+    rend(const _Container& __cont) -> decltype(__cont.rend())
+    { return __cont.rend(); }
+
+  /**
+   *  @brief  Return a reverse iterator pointing to the last element of
+   *          the array.
+   *  @param  __arr  Array.
+   */
+  template<typename _Tp, size_t _Nm>
+    [[__nodiscard__]]
+    inline _GLIBCXX17_CONSTEXPR reverse_iterator<_Tp*>
+    rbegin(_Tp (&__arr)[_Nm]) noexcept
+    { return reverse_iterator<_Tp*>(__arr + _Nm); }
+
+  /**
+   *  @brief  Return a reverse iterator pointing one past the first element of
+   *          the array.
+   *  @param  __arr  Array.
+   */
+  template<typename _Tp, size_t _Nm>
+    [[__nodiscard__]]
+    inline _GLIBCXX17_CONSTEXPR reverse_iterator<_Tp*>
+    rend(_Tp (&__arr)[_Nm]) noexcept
+    { return reverse_iterator<_Tp*>(__arr); }
+
+  /**
+   *  @brief  Return a reverse iterator pointing to the last element of
+   *          the initializer_list.
+   *  @param  __il  initializer_list.
+   */
+  template<typename _Tp>
+    [[__nodiscard__]]
+    inline _GLIBCXX17_CONSTEXPR reverse_iterator<const _Tp*>
+    rbegin(initializer_list<_Tp> __il) noexcept
+    { return reverse_iterator<const _Tp*>(__il.end()); }
+
+  /**
+   *  @brief  Return a reverse iterator pointing one past the first element of
+   *          the initializer_list.
+   *  @param  __il  initializer_list.
+   */
+  template<typename _Tp>
+    [[__nodiscard__]]
+    inline _GLIBCXX17_CONSTEXPR reverse_iterator<const _Tp*>
+    rend(initializer_list<_Tp> __il) noexcept
+    { return reverse_iterator<const _Tp*>(__il.begin()); }
+
+  /**
+   *  @brief  Return a reverse iterator pointing to the last element of
+   *          the const container.
+   *  @param  __cont  Container.
+   */
+  template<typename _Container>
+    [[__nodiscard__]]
+    inline _GLIBCXX17_CONSTEXPR auto
+    crbegin(const _Container& __cont) -> decltype(std::rbegin(__cont))
+    { return std::rbegin(__cont); }
+
+  /**
+   *  @brief  Return a reverse iterator pointing one past the first element of
+   *          the const container.
+   *  @param  __cont  Container.
+   */
+  template<typename _Container>
+    [[__nodiscard__]]
+    inline _GLIBCXX17_CONSTEXPR auto
+    crend(const _Container& __cont) -> decltype(std::rend(__cont))
+    { return std::rend(__cont); }
+
+#endif // C++14
+
+#if __cplusplus >= 201703L
+#define __cpp_lib_nonmember_container_access 201411L
+
+  /**
+   *  @brief  Return the size of a container.
+   *  @param  __cont  Container.
+   */
+  template <typename _Container>
+    [[nodiscard]]
+    constexpr auto
+    size(const _Container& __cont) noexcept(noexcept(__cont.size()))
+    -> decltype(__cont.size())
+    { return __cont.size(); }
+
+  /**
+   *  @brief  Return the size of an array.
+   */
+  template <typename _Tp, size_t _Nm>
+    [[nodiscard]]
+    constexpr size_t
+    size(const _Tp (&)[_Nm]) noexcept
+    { return _Nm; }
+
+  /**
+   *  @brief  Return whether a container is empty.
+   *  @param  __cont  Container.
+   */
+  template <typename _Container>
+    [[nodiscard]] constexpr auto
+    empty(const _Container& __cont) noexcept(noexcept(__cont.empty()))
+    -> decltype(__cont.empty())
+    { return __cont.empty(); }
+
+  /**
+   *  @brief  Return whether an array is empty (always false).
+   */
+  template <typename _Tp, size_t _Nm>
+    [[nodiscard]] constexpr bool
+    empty(const _Tp (&)[_Nm]) noexcept
+    { return false; }
+
+  /**
+   *  @brief  Return whether an initializer_list is empty.
+   *  @param  __il  Initializer list.
+   */
+  template <typename _Tp>
+    [[nodiscard]] constexpr bool
+    empty(initializer_list<_Tp> __il) noexcept
+    { return __il.size() == 0;}
+
+  /**
+   *  @brief  Return the data pointer of a container.
+   *  @param  __cont  Container.
+   */
+  template <typename _Container>
+    [[nodiscard]]
+    constexpr auto
+    data(_Container& __cont) noexcept(noexcept(__cont.data()))
+    -> decltype(__cont.data())
+    { return __cont.data(); }
+
+  /**
+   *  @brief  Return the data pointer of a const container.
+   *  @param  __cont  Container.
+   */
+  template <typename _Container>
+    [[nodiscard]]
+    constexpr auto
+    data(const _Container& __cont) noexcept(noexcept(__cont.data()))
+    -> decltype(__cont.data())
+    { return __cont.data(); }
+
+  /**
+   *  @brief  Return the data pointer of an array.
+   *  @param  __array  Array.
+   */
+  template <typename _Tp, size_t _Nm>
+    [[nodiscard]]
+    constexpr _Tp*
+    data(_Tp (&__array)[_Nm]) noexcept
+    { return __array; }
+
+  /**
+   *  @brief  Return the data pointer of an initializer list.
+   *  @param  __il  Initializer list.
+   */
+  template <typename _Tp>
+    [[nodiscard]]
+    constexpr const _Tp*
+    data(initializer_list<_Tp> __il) noexcept
+    { return __il.begin(); }
+
+#if __cplusplus > 201703L
+#define __cpp_lib_ssize 201902L
+  template<typename _Container>
+    [[nodiscard]]
+    constexpr auto
+    ssize(const _Container& __cont)
+    noexcept(noexcept(__cont.size()))
+    -> common_type_t<ptrdiff_t, make_signed_t<decltype(__cont.size())>>
+    {
+      using type = make_signed_t<decltype(__cont.size())>;
+      return static_cast<common_type_t<ptrdiff_t, type>>(__cont.size());
+    }
+
+  template<typename _Tp, ptrdiff_t _Num>
+    [[nodiscard]]
+    constexpr ptrdiff_t
+    ssize(const _Tp (&)[_Num]) noexcept
+    { return _Num; }
+#endif // C++20
+
+#endif // C++17
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif // C++11
+#endif // _GLIBCXX_RANGE_ACCESS_H
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@range_access.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@range_access.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@refwrap.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@refwrap.h
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@refwrap.h
@@ -0,0 +1,410 @@
+// Implementation of std::reference_wrapper -*- C++ -*-
+
+// Copyright (C) 2004-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file include/bits/refwrap.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{functional}
+ */
+
+#ifndef _GLIBCXX_REFWRAP_H
+#define _GLIBCXX_REFWRAP_H 1
+
+#pragma GCC system_header
+
+#if __cplusplus >= 201103L
+
+#include <bits/move.h>
+#include <bits/invoke.h>
+#include <bits/stl_function.h> // for unary_function and binary_function
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /// @cond undocumented
+
+  /**
+   * Derives from @c unary_function or @c binary_function, or perhaps
+   * nothing, depending on the number of arguments provided. The
+   * primary template is the basis case, which derives nothing.
+   */
+  template<typename _Res, typename... _ArgTypes>
+    struct _Maybe_unary_or_binary_function { };
+
+// Ignore warnings about unary_function and binary_function.
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+
+  /// Derives from @c unary_function, as appropriate.
+  template<typename _Res, typename _T1>
+    struct _Maybe_unary_or_binary_function<_Res, _T1>
+    : std::unary_function<_T1, _Res> { };
+
+  /// Derives from @c binary_function, as appropriate.
+  template<typename _Res, typename _T1, typename _T2>
+    struct _Maybe_unary_or_binary_function<_Res, _T1, _T2>
+    : std::binary_function<_T1, _T2, _Res> { };
+
+#pragma GCC diagnostic pop
+
+  template<typename _Signature>
+    struct _Mem_fn_traits;
+
+  template<typename _Res, typename _Class, typename... _ArgTypes>
+    struct _Mem_fn_traits_base
+    {
+      using __result_type = _Res;
+      using __maybe_type
+	= _Maybe_unary_or_binary_function<_Res, _Class*, _ArgTypes...>;
+      using __arity = integral_constant<size_t, sizeof...(_ArgTypes)>;
+    };
+
+#define _GLIBCXX_MEM_FN_TRAITS2(_CV, _REF, _LVAL, _RVAL)		\
+  template<typename _Res, typename _Class, typename... _ArgTypes>	\
+    struct _Mem_fn_traits<_Res (_Class::*)(_ArgTypes...) _CV _REF>	\
+    : _Mem_fn_traits_base<_Res, _CV _Class, _ArgTypes...>		\
+    {									\
+      using __vararg = false_type;					\
+    };									\
+  template<typename _Res, typename _Class, typename... _ArgTypes>	\
+    struct _Mem_fn_traits<_Res (_Class::*)(_ArgTypes... ...) _CV _REF>	\
+    : _Mem_fn_traits_base<_Res, _CV _Class, _ArgTypes...>		\
+    {									\
+      using __vararg = true_type;					\
+    };
+
+#define _GLIBCXX_MEM_FN_TRAITS(_REF, _LVAL, _RVAL)		\
+  _GLIBCXX_MEM_FN_TRAITS2(		, _REF, _LVAL, _RVAL)	\
+  _GLIBCXX_MEM_FN_TRAITS2(const		, _REF, _LVAL, _RVAL)	\
+  _GLIBCXX_MEM_FN_TRAITS2(volatile	, _REF, _LVAL, _RVAL)	\
+  _GLIBCXX_MEM_FN_TRAITS2(const volatile, _REF, _LVAL, _RVAL)
+
+_GLIBCXX_MEM_FN_TRAITS( , true_type, true_type)
+_GLIBCXX_MEM_FN_TRAITS(&, true_type, false_type)
+_GLIBCXX_MEM_FN_TRAITS(&&, false_type, true_type)
+
+#if __cplusplus > 201402L
+_GLIBCXX_MEM_FN_TRAITS(noexcept, true_type, true_type)
+_GLIBCXX_MEM_FN_TRAITS(& noexcept, true_type, false_type)
+_GLIBCXX_MEM_FN_TRAITS(&& noexcept, false_type, true_type)
+#endif
+
+#undef _GLIBCXX_MEM_FN_TRAITS
+#undef _GLIBCXX_MEM_FN_TRAITS2
+
+  /// If we have found a result_type, extract it.
+  template<typename _Functor, typename = __void_t<>>
+    struct _Maybe_get_result_type
+    { };
+
+  template<typename _Functor>
+    struct _Maybe_get_result_type<_Functor,
+				  __void_t<typename _Functor::result_type>>
+    { typedef typename _Functor::result_type result_type; };
+
+  /**
+   *  Base class for any function object that has a weak result type, as
+   *  defined in 20.8.2 [func.require] of C++11.
+  */
+  template<typename _Functor>
+    struct _Weak_result_type_impl
+    : _Maybe_get_result_type<_Functor>
+    { };
+
+  /// Retrieve the result type for a function type.
+  template<typename _Res, typename... _ArgTypes _GLIBCXX_NOEXCEPT_PARM>
+    struct _Weak_result_type_impl<_Res(_ArgTypes...) _GLIBCXX_NOEXCEPT_QUAL>
+    { typedef _Res result_type; };
+
+  /// Retrieve the result type for a varargs function type.
+  template<typename _Res, typename... _ArgTypes _GLIBCXX_NOEXCEPT_PARM>
+    struct _Weak_result_type_impl<_Res(_ArgTypes......) _GLIBCXX_NOEXCEPT_QUAL>
+    { typedef _Res result_type; };
+
+  /// Retrieve the result type for a function pointer.
+  template<typename _Res, typename... _ArgTypes _GLIBCXX_NOEXCEPT_PARM>
+    struct _Weak_result_type_impl<_Res(*)(_ArgTypes...) _GLIBCXX_NOEXCEPT_QUAL>
+    { typedef _Res result_type; };
+
+  /// Retrieve the result type for a varargs function pointer.
+  template<typename _Res, typename... _ArgTypes _GLIBCXX_NOEXCEPT_PARM>
+    struct
+    _Weak_result_type_impl<_Res(*)(_ArgTypes......) _GLIBCXX_NOEXCEPT_QUAL>
+    { typedef _Res result_type; };
+
+  // Let _Weak_result_type_impl perform the real work.
+  template<typename _Functor,
+	   bool = is_member_function_pointer<_Functor>::value>
+    struct _Weak_result_type_memfun
+    : _Weak_result_type_impl<_Functor>
+    { };
+
+  // A pointer to member function has a weak result type.
+  template<typename _MemFunPtr>
+    struct _Weak_result_type_memfun<_MemFunPtr, true>
+    {
+      using result_type = typename _Mem_fn_traits<_MemFunPtr>::__result_type;
+    };
+
+  // A pointer to data member doesn't have a weak result type.
+  template<typename _Func, typename _Class>
+    struct _Weak_result_type_memfun<_Func _Class::*, false>
+    { };
+
+  /**
+   *  Strip top-level cv-qualifiers from the function object and let
+   *  _Weak_result_type_memfun perform the real work.
+  */
+  template<typename _Functor>
+    struct _Weak_result_type
+    : _Weak_result_type_memfun<typename remove_cv<_Functor>::type>
+    { };
+
+#if __cplusplus <= 201703L
+  // Detect nested argument_type.
+  template<typename _Tp, typename = __void_t<>>
+    struct _Refwrap_base_arg1
+    { };
+
+  // Nested argument_type.
+  template<typename _Tp>
+    struct _Refwrap_base_arg1<_Tp,
+			      __void_t<typename _Tp::argument_type>>
+    {
+      typedef typename _Tp::argument_type argument_type;
+    };
+
+  // Detect nested first_argument_type and second_argument_type.
+  template<typename _Tp, typename = __void_t<>>
+    struct _Refwrap_base_arg2
+    { };
+
+  // Nested first_argument_type and second_argument_type.
+  template<typename _Tp>
+    struct _Refwrap_base_arg2<_Tp,
+			      __void_t<typename _Tp::first_argument_type,
+				       typename _Tp::second_argument_type>>
+    {
+      typedef typename _Tp::first_argument_type first_argument_type;
+      typedef typename _Tp::second_argument_type second_argument_type;
+    };
+
+  /**
+   *  Derives from unary_function or binary_function when it
+   *  can. Specializations handle all of the easy cases. The primary
+   *  template determines what to do with a class type, which may
+   *  derive from both unary_function and binary_function.
+  */
+  template<typename _Tp>
+    struct _Reference_wrapper_base
+    : _Weak_result_type<_Tp>, _Refwrap_base_arg1<_Tp>, _Refwrap_base_arg2<_Tp>
+    { };
+
+// Ignore warnings about unary_function and binary_function.
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+
+  // - a function type (unary)
+  template<typename _Res, typename _T1 _GLIBCXX_NOEXCEPT_PARM>
+    struct _Reference_wrapper_base<_Res(_T1) _GLIBCXX_NOEXCEPT_QUAL>
+    : unary_function<_T1, _Res>
+    { };
+
+  template<typename _Res, typename _T1>
+    struct _Reference_wrapper_base<_Res(_T1) const>
+    : unary_function<_T1, _Res>
+    { };
+
+  template<typename _Res, typename _T1>
+    struct _Reference_wrapper_base<_Res(_T1) volatile>
+    : unary_function<_T1, _Res>
+    { };
+
+  template<typename _Res, typename _T1>
+    struct _Reference_wrapper_base<_Res(_T1) const volatile>
+    : unary_function<_T1, _Res>
+    { };
+
+  // - a function type (binary)
+  template<typename _Res, typename _T1, typename _T2 _GLIBCXX_NOEXCEPT_PARM>
+    struct _Reference_wrapper_base<_Res(_T1, _T2) _GLIBCXX_NOEXCEPT_QUAL>
+    : binary_function<_T1, _T2, _Res>
+    { };
+
+  template<typename _Res, typename _T1, typename _T2>
+    struct _Reference_wrapper_base<_Res(_T1, _T2) const>
+    : binary_function<_T1, _T2, _Res>
+    { };
+
+  template<typename _Res, typename _T1, typename _T2>
+    struct _Reference_wrapper_base<_Res(_T1, _T2) volatile>
+    : binary_function<_T1, _T2, _Res>
+    { };
+
+  template<typename _Res, typename _T1, typename _T2>
+    struct _Reference_wrapper_base<_Res(_T1, _T2) const volatile>
+    : binary_function<_T1, _T2, _Res>
+    { };
+
+  // - a function pointer type (unary)
+  template<typename _Res, typename _T1 _GLIBCXX_NOEXCEPT_PARM>
+    struct _Reference_wrapper_base<_Res(*)(_T1) _GLIBCXX_NOEXCEPT_QUAL>
+    : unary_function<_T1, _Res>
+    { };
+
+  // - a function pointer type (binary)
+  template<typename _Res, typename _T1, typename _T2 _GLIBCXX_NOEXCEPT_PARM>
+    struct _Reference_wrapper_base<_Res(*)(_T1, _T2) _GLIBCXX_NOEXCEPT_QUAL>
+    : binary_function<_T1, _T2, _Res>
+    { };
+
+  template<typename _Tp, bool = is_member_function_pointer<_Tp>::value>
+    struct _Reference_wrapper_base_memfun
+    : _Reference_wrapper_base<_Tp>
+    { };
+
+  template<typename _MemFunPtr>
+    struct _Reference_wrapper_base_memfun<_MemFunPtr, true>
+    : _Mem_fn_traits<_MemFunPtr>::__maybe_type
+    {
+      using result_type = typename _Mem_fn_traits<_MemFunPtr>::__result_type;
+    };
+#pragma GCC diagnostic pop
+#endif // ! C++20
+
+  /// @endcond
+
+  /**
+   *  @brief Primary class template for reference_wrapper.
+   *  @ingroup functors
+   */
+  template<typename _Tp>
+    class reference_wrapper
+#if __cplusplus <= 201703L
+    // In C++20 std::reference_wrapper<T> allows T to be incomplete,
+    // so checking for nested types could result in ODR violations.
+    : public _Reference_wrapper_base_memfun<typename remove_cv<_Tp>::type>
+#endif
+    {
+      _Tp* _M_data;
+
+      _GLIBCXX20_CONSTEXPR
+      static _Tp* _S_fun(_Tp& __r) noexcept { return std::__addressof(__r); }
+
+      static void _S_fun(_Tp&&) = delete;
+
+      template<typename _Up, typename _Up2 = __remove_cvref_t<_Up>>
+	using __not_same
+	  = typename enable_if<!is_same<reference_wrapper, _Up2>::value>::type;
+
+    public:
+      typedef _Tp type;
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 2993. reference_wrapper<T> conversion from T&&
+      // 3041. Unnecessary decay in reference_wrapper
+      template<typename _Up, typename = __not_same<_Up>, typename
+		= decltype(reference_wrapper::_S_fun(std::declval<_Up>()))>
+	_GLIBCXX20_CONSTEXPR
+	reference_wrapper(_Up&& __uref)
+	noexcept(noexcept(reference_wrapper::_S_fun(std::declval<_Up>())))
+	: _M_data(reference_wrapper::_S_fun(std::forward<_Up>(__uref)))
+	{ }
+
+      reference_wrapper(const reference_wrapper&) = default;
+
+      reference_wrapper&
+      operator=(const reference_wrapper&) = default;
+
+      _GLIBCXX20_CONSTEXPR
+      operator _Tp&() const noexcept
+      { return this->get(); }
+
+      _GLIBCXX20_CONSTEXPR
+      _Tp&
+      get() const noexcept
+      { return *_M_data; }
+
+      template<typename... _Args>
+	_GLIBCXX20_CONSTEXPR
+	typename result_of<_Tp&(_Args&&...)>::type
+	operator()(_Args&&... __args) const
+	{
+#if __cplusplus > 201703L
+	  if constexpr (is_object_v<type>)
+	    static_assert(sizeof(type), "type must be complete");
+#endif
+	  return std::__invoke(get(), std::forward<_Args>(__args)...);
+	}
+    };
+
+#if __cpp_deduction_guides
+  template<typename _Tp>
+    reference_wrapper(_Tp&) -> reference_wrapper<_Tp>;
+#endif
+
+  /// @relates reference_wrapper @{
+
+  /// Denotes a reference should be taken to a variable.
+  template<typename _Tp>
+    _GLIBCXX20_CONSTEXPR
+    inline reference_wrapper<_Tp>
+    ref(_Tp& __t) noexcept
+    { return reference_wrapper<_Tp>(__t); }
+
+  /// Denotes a const reference should be taken to a variable.
+  template<typename _Tp>
+    _GLIBCXX20_CONSTEXPR
+    inline reference_wrapper<const _Tp>
+    cref(const _Tp& __t) noexcept
+    { return reference_wrapper<const _Tp>(__t); }
+
+  template<typename _Tp>
+    void ref(const _Tp&&) = delete;
+
+  template<typename _Tp>
+    void cref(const _Tp&&) = delete;
+
+  /// std::ref overload to prevent wrapping a reference_wrapper
+  template<typename _Tp>
+    _GLIBCXX20_CONSTEXPR
+    inline reference_wrapper<_Tp>
+    ref(reference_wrapper<_Tp> __t) noexcept
+    { return __t; }
+
+  /// std::cref overload to prevent wrapping a reference_wrapper
+  template<typename _Tp>
+    _GLIBCXX20_CONSTEXPR
+    inline reference_wrapper<const _Tp>
+    cref(reference_wrapper<_Tp> __t) noexcept
+    { return { __t.get() }; }
+
+  /// @}
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif // C++11
+
+#endif // _GLIBCXX_REFWRAP_H
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@regex.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@regex.h
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@@ -0,0 +1,3026 @@
+// class template regex -*- C++ -*-
+
+// Copyright (C) 2010-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/**
+ *  @file bits/regex.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{regex}
+ */
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+_GLIBCXX_BEGIN_NAMESPACE_CXX11
+  template<typename, typename>
+    class basic_regex;
+
+  template<typename _Bi_iter, typename _Alloc>
+    class match_results;
+
+_GLIBCXX_END_NAMESPACE_CXX11
+
+namespace __detail
+{
+  enum class _RegexExecutorPolicy : int { _S_auto, _S_alternate };
+
+  template<typename _BiIter, typename _Alloc,
+	   typename _CharT, typename _TraitsT>
+    bool
+    __regex_algo_impl(_BiIter __s, _BiIter __e,
+		      match_results<_BiIter, _Alloc>&      __m,
+		      const basic_regex<_CharT, _TraitsT>& __re,
+		      regex_constants::match_flag_type     __flags,
+		      _RegexExecutorPolicy		   __policy,
+		      bool				   __match_mode);
+
+  template<typename, typename, typename, bool>
+    class _Executor;
+
+  template<typename _Tp>
+    struct __is_contiguous_iter : false_type { };
+
+  template<typename _Tp>
+    struct __is_contiguous_iter<_Tp*> : true_type { };
+
+  template<typename _Tp, typename _Cont>
+    struct __is_contiguous_iter<__gnu_cxx::__normal_iterator<_Tp*, _Cont>>
+    : true_type { };
+}
+
+_GLIBCXX_BEGIN_NAMESPACE_CXX11
+
+  /**
+   * @addtogroup regex
+   * @{
+   */
+
+  /**
+   * @brief Describes aspects of a regular expression.
+   *
+   * A regular expression traits class that satisfies the requirements of
+   * section [28.7].
+   *
+   * The class %regex is parameterized around a set of related types and
+   * functions used to complete the definition of its semantics.  This class
+   * satisfies the requirements of such a traits class.
+   */
+  template<typename _Ch_type>
+    class regex_traits
+    {
+    public:
+      typedef _Ch_type				char_type;
+      typedef std::basic_string<char_type>	string_type;
+      typedef std::locale			locale_type;
+
+    private:
+      struct _RegexMask
+	{
+	  typedef std::ctype_base::mask _BaseType;
+	  _BaseType _M_base;
+	  unsigned char _M_extended;
+	  static constexpr unsigned char _S_under = 1 << 0;
+	  static constexpr unsigned char _S_valid_mask = 0x1;
+
+	  constexpr _RegexMask(_BaseType __base = 0,
+			       unsigned char __extended = 0)
+	  : _M_base(__base), _M_extended(__extended)
+	  { }
+
+	  constexpr _RegexMask
+	  operator&(_RegexMask __other) const
+	  {
+	    return _RegexMask(_M_base & __other._M_base,
+			      _M_extended & __other._M_extended);
+	  }
+
+	  constexpr _RegexMask
+	  operator|(_RegexMask __other) const
+	  {
+	    return _RegexMask(_M_base | __other._M_base,
+			      _M_extended | __other._M_extended);
+	  }
+
+	  constexpr _RegexMask
+	  operator^(_RegexMask __other) const
+	  {
+	    return _RegexMask(_M_base ^ __other._M_base,
+			      _M_extended ^ __other._M_extended);
+	  }
+
+	  constexpr _RegexMask
+	  operator~() const
+	  { return _RegexMask(~_M_base, ~_M_extended); }
+
+	  _RegexMask&
+	  operator&=(_RegexMask __other)
+	  { return *this = (*this) & __other; }
+
+	  _RegexMask&
+	  operator|=(_RegexMask __other)
+	  { return *this = (*this) | __other; }
+
+	  _RegexMask&
+	  operator^=(_RegexMask __other)
+	  { return *this = (*this) ^ __other; }
+
+	  constexpr bool
+	  operator==(_RegexMask __other) const
+	  {
+	    return (_M_extended & _S_valid_mask)
+		   == (__other._M_extended & _S_valid_mask)
+		     && _M_base == __other._M_base;
+	  }
+
+#if __cpp_impl_three_way_comparison < 201907L
+	  constexpr bool
+	  operator!=(_RegexMask __other) const
+	  { return !((*this) == __other); }
+#endif
+	};
+
+    public:
+      typedef _RegexMask char_class_type;
+
+    public:
+      /**
+       * @brief Constructs a default traits object.
+       */
+      regex_traits() { }
+
+      /**
+       * @brief Gives the length of a C-style string starting at @p __p.
+       *
+       * @param __p a pointer to the start of a character sequence.
+       *
+       * @returns the number of characters between @p *__p and the first
+       * default-initialized value of type @p char_type.  In other words, uses
+       * the C-string algorithm for determining the length of a sequence of
+       * characters.
+       */
+      static std::size_t
+      length(const char_type* __p)
+      { return string_type::traits_type::length(__p); }
+
+      /**
+       * @brief Performs the identity translation.
+       *
+       * @param __c A character to the locale-specific character set.
+       *
+       * @returns __c.
+       */
+      char_type
+      translate(char_type __c) const
+      { return __c; }
+
+      /**
+       * @brief Translates a character into a case-insensitive equivalent.
+       *
+       * @param __c A character to the locale-specific character set.
+       *
+       * @returns the locale-specific lower-case equivalent of __c.
+       * @throws std::bad_cast if the imbued locale does not support the ctype
+       *         facet.
+       */
+      char_type
+      translate_nocase(char_type __c) const
+      {
+	typedef std::ctype<char_type> __ctype_type;
+	const __ctype_type& __fctyp(use_facet<__ctype_type>(_M_locale));
+	return __fctyp.tolower(__c);
+      }
+
+      /**
+       * @brief Gets a sort key for a character sequence.
+       *
+       * @param __first beginning of the character sequence.
+       * @param __last  one-past-the-end of the character sequence.
+       *
+       * Returns a sort key for the character sequence designated by the
+       * iterator range [F1, F2) such that if the character sequence [G1, G2)
+       * sorts before the character sequence [H1, H2) then
+       * v.transform(G1, G2) < v.transform(H1, H2).
+       *
+       * What this really does is provide a more efficient way to compare a
+       * string to multiple other strings in locales with fancy collation
+       * rules and equivalence classes.
+       *
+       * @returns a locale-specific sort key equivalent to the input range.
+       *
+       * @throws std::bad_cast if the current locale does not have a collate
+       *         facet.
+       */
+      template<typename _Fwd_iter>
+	string_type
+	transform(_Fwd_iter __first, _Fwd_iter __last) const
+	{
+	  typedef std::collate<char_type> __collate_type;
+	  const __collate_type& __fclt(use_facet<__collate_type>(_M_locale));
+	  string_type __s(__first, __last);
+	  return __fclt.transform(__s.data(), __s.data() + __s.size());
+	}
+
+      /**
+       * @brief Gets a sort key for a character sequence, independent of case.
+       *
+       * @param __first beginning of the character sequence.
+       * @param __last  one-past-the-end of the character sequence.
+       *
+       * Effects: if typeid(use_facet<collate<_Ch_type> >) ==
+       * typeid(collate_byname<_Ch_type>) and the form of the sort key
+       * returned by collate_byname<_Ch_type>::transform(__first, __last)
+       * is known and can be converted into a primary sort key
+       * then returns that key, otherwise returns an empty string.
+       *
+       * @todo Implement this function correctly.
+       */
+      template<typename _Fwd_iter>
+	string_type
+	transform_primary(_Fwd_iter __first, _Fwd_iter __last) const
+	{
+	  // TODO : this is not entirely correct.
+	  // This function requires extra support from the platform.
+	  //
+	  // Read http://gcc.gnu.org/ml/libstdc++/2013-09/msg00117.html and
+	  // http://www.open-std.org/Jtc1/sc22/wg21/docs/papers/2003/n1429.htm
+	  // for details.
+	  typedef std::ctype<char_type> __ctype_type;
+	  const __ctype_type& __fctyp(use_facet<__ctype_type>(_M_locale));
+	  _GLIBCXX_STD_C::vector<char_type> __s(__first, __last);
+	  __fctyp.tolower(__s.data(), __s.data() + __s.size());
+	  return this->transform(__s.data(), __s.data() + __s.size());
+	}
+
+      /**
+       * @brief Gets a collation element by name.
+       *
+       * @param __first beginning of the collation element name.
+       * @param __last  one-past-the-end of the collation element name.
+       *
+       * @returns a sequence of one or more characters that represents the
+       * collating element consisting of the character sequence designated by
+       * the iterator range [__first, __last). Returns an empty string if the
+       * character sequence is not a valid collating element.
+       */
+      template<typename _Fwd_iter>
+	string_type
+	lookup_collatename(_Fwd_iter __first, _Fwd_iter __last) const;
+
+      /**
+       * @brief Maps one or more characters to a named character
+       *        classification.
+       *
+       * @param __first beginning of the character sequence.
+       * @param __last  one-past-the-end of the character sequence.
+       * @param __icase ignores the case of the classification name.
+       *
+       * @returns an unspecified value that represents the character
+       * classification named by the character sequence designated by
+       * the iterator range [__first, __last). If @p icase is true,
+       * the returned mask identifies the classification regardless of
+       * the case of the characters to be matched (for example,
+       * [[:lower:]] is the same as [[:alpha:]]), otherwise a
+       * case-dependent classification is returned.  The value
+       * returned shall be independent of the case of the characters
+       * in the character sequence. If the name is not recognized then
+       * returns a value that compares equal to 0.
+       *
+       * At least the following names (or their wide-character equivalent) are
+       * supported.
+       * - d
+       * - w
+       * - s
+       * - alnum
+       * - alpha
+       * - blank
+       * - cntrl
+       * - digit
+       * - graph
+       * - lower
+       * - print
+       * - punct
+       * - space
+       * - upper
+       * - xdigit
+       */
+      template<typename _Fwd_iter>
+	char_class_type
+	lookup_classname(_Fwd_iter __first, _Fwd_iter __last,
+			 bool __icase = false) const;
+
+      /**
+       * @brief Determines if @p c is a member of an identified class.
+       *
+       * @param __c a character.
+       * @param __f a class type (as returned from lookup_classname).
+       *
+       * @returns true if the character @p __c is a member of the classification
+       * represented by @p __f, false otherwise.
+       *
+       * @throws std::bad_cast if the current locale does not have a ctype
+       *         facet.
+       */
+      bool
+      isctype(_Ch_type __c, char_class_type __f) const;
+
+      /**
+       * @brief Converts a digit to an int.
+       *
+       * @param __ch    a character representing a digit.
+       * @param __radix the radix if the numeric conversion (limited to 8, 10,
+       *              or 16).
+       *
+       * @returns the value represented by the digit __ch in base radix if the
+       * character __ch is a valid digit in base radix; otherwise returns -1.
+       */
+      int
+      value(_Ch_type __ch, int __radix) const;
+
+      /**
+       * @brief Imbues the regex_traits object with a copy of a new locale.
+       *
+       * @param __loc A locale.
+       *
+       * @returns a copy of the previous locale in use by the regex_traits
+       *          object.
+       *
+       * @note Calling imbue with a different locale than the one currently in
+       *       use invalidates all cached data held by *this.
+       */
+      locale_type
+      imbue(locale_type __loc)
+      {
+	std::swap(_M_locale, __loc);
+	return __loc;
+      }
+
+      /**
+       * @brief Gets a copy of the current locale in use by the regex_traits
+       * object.
+       */
+      locale_type
+      getloc() const
+      { return _M_locale; }
+
+    protected:
+      locale_type _M_locale;
+    };
+
+  // [7.8] Class basic_regex
+  /**
+   * Objects of specializations of this class represent regular expressions
+   * constructed from sequences of character type @p _Ch_type.
+   *
+   * Storage for the regular expression is allocated and deallocated as
+   * necessary by the member functions of this class.
+   */
+  template<typename _Ch_type, typename _Rx_traits = regex_traits<_Ch_type>>
+    class basic_regex
+    {
+    public:
+      static_assert(is_same<_Ch_type, typename _Rx_traits::char_type>::value,
+		    "regex traits class must have the same char_type");
+
+      // types:
+      typedef _Ch_type				  value_type;
+      typedef _Rx_traits			  traits_type;
+      typedef typename traits_type::string_type   string_type;
+      typedef regex_constants::syntax_option_type flag_type;
+      typedef typename traits_type::locale_type   locale_type;
+
+      /**
+       * @name Constants
+       * std [28.8.1](1)
+       */
+      ///@{
+      static constexpr flag_type icase = regex_constants::icase;
+      static constexpr flag_type nosubs = regex_constants::nosubs;
+      static constexpr flag_type optimize = regex_constants::optimize;
+      static constexpr flag_type collate = regex_constants::collate;
+      static constexpr flag_type ECMAScript = regex_constants::ECMAScript;
+      static constexpr flag_type basic = regex_constants::basic;
+      static constexpr flag_type extended = regex_constants::extended;
+      static constexpr flag_type awk = regex_constants::awk;
+      static constexpr flag_type grep = regex_constants::grep;
+      static constexpr flag_type egrep = regex_constants::egrep;
+#if __cplusplus >= 201703L || !defined __STRICT_ANSI__
+      static constexpr flag_type multiline = regex_constants::multiline;
+#endif
+      ///@}
+
+      // [7.8.2] construct/copy/destroy
+      /**
+       * Constructs a basic regular expression that does not match any
+       * character sequence.
+       */
+      basic_regex() noexcept
+      : _M_flags(ECMAScript), _M_loc(), _M_automaton(nullptr)
+      { }
+
+      /**
+       * @brief Constructs a basic regular expression from the
+       * sequence [__p, __p + char_traits<_Ch_type>::length(__p))
+       * interpreted according to the flags in @p __f.
+       *
+       * @param __p A pointer to the start of a C-style null-terminated string
+       *          containing a regular expression.
+       * @param __f Flags indicating the syntax rules and options.
+       *
+       * @throws regex_error if @p __p is not a valid regular expression.
+       */
+      explicit
+      basic_regex(const _Ch_type* __p, flag_type __f = ECMAScript)
+      { _M_compile(__p, __p + _Rx_traits::length(__p), __f); }
+
+      /**
+       * @brief Constructs a basic regular expression from the sequence
+       * [p, p + len) interpreted according to the flags in @p f.
+       *
+       * @param __p   A pointer to the start of a string containing a regular
+       *              expression.
+       * @param __len The length of the string containing the regular
+       *              expression.
+       * @param __f   Flags indicating the syntax rules and options.
+       *
+       * @throws regex_error if @p __p is not a valid regular expression.
+       */
+      basic_regex(const _Ch_type* __p, std::size_t __len,
+		  flag_type __f = ECMAScript)
+      {
+	__glibcxx_requires_string_len(__p, __len);
+	_M_compile(__p, __p + __len, __f);
+      }
+
+      /**
+       * @brief Copy-constructs a basic regular expression.
+       *
+       * @param __rhs A @p regex object.
+       */
+      basic_regex(const basic_regex& __rhs) = default;
+
+      /**
+       * @brief Move-constructs a basic regular expression.
+       *
+       * @param __rhs A @p regex object.
+       */
+      basic_regex(basic_regex&& __rhs) noexcept = default;
+
+      /**
+       * @brief Constructs a basic regular expression from the string
+       * @p s interpreted according to the flags in @p f.
+       *
+       * @param __s A string containing a regular expression.
+       * @param __f Flags indicating the syntax rules and options.
+       *
+       * @throws regex_error if @p __s is not a valid regular expression.
+       */
+      template<typename _Ch_traits, typename _Ch_alloc>
+	explicit
+	basic_regex(const std::basic_string<_Ch_type, _Ch_traits,
+					    _Ch_alloc>& __s,
+		    flag_type __f = ECMAScript)
+	{ _M_compile(__s.data(), __s.data() + __s.size(), __f); }
+
+      /**
+       * @brief Constructs a basic regular expression from the range
+       * [first, last) interpreted according to the flags in @p f.
+       *
+       * @param __first The start of a range containing a valid regular
+       *                expression.
+       * @param __last  The end of a range containing a valid regular
+       *                expression.
+       * @param __f     The format flags of the regular expression.
+       *
+       * @throws regex_error if @p [__first, __last) is not a valid regular
+       *         expression.
+       */
+      template<typename _FwdIter>
+	basic_regex(_FwdIter __first, _FwdIter __last,
+		    flag_type __f = ECMAScript)
+	{ this->assign(__first, __last, __f); }
+
+      /**
+       * @brief Constructs a basic regular expression from an initializer list.
+       *
+       * @param __l  The initializer list.
+       * @param __f  The format flags of the regular expression.
+       *
+       * @throws regex_error if @p __l is not a valid regular expression.
+       */
+      basic_regex(initializer_list<_Ch_type> __l, flag_type __f = ECMAScript)
+      { _M_compile(__l.begin(), __l.end(), __f); }
+
+      /**
+       * @brief Destroys a basic regular expression.
+       */
+      ~basic_regex()
+      { }
+
+      /**
+       * @brief Assigns one regular expression to another.
+       */
+      basic_regex&
+      operator=(const basic_regex&) = default;
+
+      /**
+       * @brief Move-assigns one regular expression to another.
+       */
+      basic_regex&
+      operator=(basic_regex&&) = default;
+
+      /**
+       * @brief Replaces a regular expression with a new one constructed from
+       * a C-style null-terminated string.
+       *
+       * @param __p A pointer to the start of a null-terminated C-style string
+       *        containing a regular expression.
+       */
+      basic_regex&
+      operator=(const _Ch_type* __p)
+      { return this->assign(__p); }
+
+      /**
+       * @brief Replaces a regular expression with a new one constructed from
+       * an initializer list.
+       *
+       * @param __l  The initializer list.
+       *
+       * @throws regex_error if @p __l is not a valid regular expression.
+       */
+      basic_regex&
+      operator=(initializer_list<_Ch_type> __l)
+      { return this->assign(__l); }
+
+      /**
+       * @brief Replaces a regular expression with a new one constructed from
+       * a string.
+       *
+       * @param __s A pointer to a string containing a regular expression.
+       */
+      template<typename _Ch_traits, typename _Alloc>
+	basic_regex&
+	operator=(const basic_string<_Ch_type, _Ch_traits, _Alloc>& __s)
+	{ return this->assign(__s); }
+
+      // [7.8.3] assign
+      /**
+       * @brief Assigns one regular expression to another.
+       *
+       * @param __rhs Another regular expression object.
+       */
+      basic_regex&
+      assign(const basic_regex& __rhs) noexcept
+      { return *this = __rhs; }
+
+      /**
+       * @brief Move-assigns one regular expression to another.
+       *
+       * @param __rhs Another regular expression object.
+       */
+      basic_regex&
+      assign(basic_regex&& __rhs) noexcept
+      { return *this = std::move(__rhs); }
+
+      /**
+       * @brief Assigns a new regular expression to a regex object from a
+       * C-style null-terminated string containing a regular expression
+       * pattern.
+       *
+       * @param __p     A pointer to a C-style null-terminated string containing
+       *              a regular expression pattern.
+       * @param __flags Syntax option flags.
+       *
+       * @throws regex_error if __p does not contain a valid regular
+       * expression pattern interpreted according to @p __flags.  If
+       * regex_error is thrown, *this remains unchanged.
+       */
+      basic_regex&
+      assign(const _Ch_type* __p, flag_type __flags = ECMAScript)
+      {
+	_M_compile(__p, __p + _Rx_traits::length(__p), __flags);
+	return *this;
+      }
+
+      /**
+       * @brief Assigns a new regular expression to a regex object from a
+       * C-style string containing a regular expression pattern.
+       *
+       * @param __p     A pointer to a C-style string containing a
+       *                regular expression pattern.
+       * @param __len   The length of the regular expression pattern string.
+       * @param __flags Syntax option flags.
+       *
+       * @throws regex_error if p does not contain a valid regular
+       * expression pattern interpreted according to @p __flags.  If
+       * regex_error is thrown, *this remains unchanged.
+       */
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 3296. Inconsistent default argument for basic_regex<>::assign
+      basic_regex&
+      assign(const _Ch_type* __p, size_t __len, flag_type __flags = ECMAScript)
+      {
+	_M_compile(__p, __p + __len, __flags);
+	return *this;
+      }
+
+      /**
+       * @brief Assigns a new regular expression to a regex object from a
+       * string containing a regular expression pattern.
+       *
+       * @param __s     A string containing a regular expression pattern.
+       * @param __flags Syntax option flags.
+       *
+       * @throws regex_error if __s does not contain a valid regular
+       * expression pattern interpreted according to @p __flags.  If
+       * regex_error is thrown, *this remains unchanged.
+       */
+      template<typename _Ch_traits, typename _Alloc>
+	basic_regex&
+	assign(const basic_string<_Ch_type, _Ch_traits, _Alloc>& __s,
+	       flag_type __flags = ECMAScript)
+	{
+	  _M_compile(__s.data(), __s.data() + __s.size(), __flags);
+	  return *this;
+	}
+
+      /**
+       * @brief Assigns a new regular expression to a regex object.
+       *
+       * @param __first The start of a range containing a valid regular
+       *                expression.
+       * @param __last  The end of a range containing a valid regular
+       *                expression.
+       * @param __flags Syntax option flags.
+       *
+       * @throws regex_error if p does not contain a valid regular
+       * expression pattern interpreted according to @p __flags.  If
+       * regex_error is thrown, the object remains unchanged.
+       */
+      template<typename _InputIterator>
+	basic_regex&
+	assign(_InputIterator __first, _InputIterator __last,
+	       flag_type __flags = ECMAScript)
+	{
+#if __cpp_if_constexpr >= 201606L
+	  using _ValT = typename iterator_traits<_InputIterator>::value_type;
+	  if constexpr (__detail::__is_contiguous_iter<_InputIterator>::value
+			&& is_same_v<_ValT, value_type>)
+	    {
+	      __glibcxx_requires_valid_range(__first, __last);
+	      if constexpr (is_pointer_v<_InputIterator>)
+		_M_compile(__first, __last, __flags);
+	      else // __normal_iterator<_T*, C>
+		_M_compile(__first.base(), __last.base(), __flags);
+	    }
+	  else
+#endif
+	  this->assign(string_type(__first, __last), __flags);
+	  return *this;
+	}
+
+      /**
+       * @brief Assigns a new regular expression to a regex object.
+       *
+       * @param __l     An initializer list representing a regular expression.
+       * @param __flags Syntax option flags.
+       *
+       * @throws regex_error if @p __l does not contain a valid
+       * regular expression pattern interpreted according to @p
+       * __flags.  If regex_error is thrown, the object remains
+       * unchanged.
+       */
+      basic_regex&
+      assign(initializer_list<_Ch_type> __l, flag_type __flags = ECMAScript)
+      {
+	_M_compile(__l.begin(), __l.end(), __flags);
+	return *this;
+      }
+
+      // [7.8.4] const operations
+      /**
+       * @brief Gets the number of marked subexpressions within the regular
+       * expression.
+       */
+      unsigned int
+      mark_count() const noexcept
+      {
+	if (_M_automaton)
+	  return _M_automaton->_M_sub_count() - 1;
+	return 0;
+      }
+
+      /**
+       * @brief Gets the flags used to construct the regular expression
+       * or in the last call to assign().
+       */
+      flag_type
+      flags() const noexcept
+      { return _M_flags; }
+
+      // [7.8.5] locale
+      /**
+       * @brief Imbues the regular expression object with the given locale.
+       *
+       * @param __loc A locale.
+       */
+      locale_type
+      imbue(locale_type __loc)
+      {
+	std::swap(__loc, _M_loc);
+	_M_automaton.reset();
+	return __loc;
+      }
+
+      /**
+       * @brief Gets the locale currently imbued in the regular expression
+       *        object.
+       */
+      locale_type
+      getloc() const noexcept
+      { return _M_loc; }
+
+      // [7.8.6] swap
+      /**
+       * @brief Swaps the contents of two regular expression objects.
+       *
+       * @param __rhs Another regular expression object.
+       */
+      void
+      swap(basic_regex& __rhs) noexcept
+      {
+	std::swap(_M_flags, __rhs._M_flags);
+	std::swap(_M_loc, __rhs._M_loc);
+	std::swap(_M_automaton, __rhs._M_automaton);
+      }
+
+#ifdef _GLIBCXX_DEBUG
+      void
+      _M_dot(std::ostream& __ostr)
+      { _M_automaton->_M_dot(__ostr); }
+#endif
+
+    private:
+      typedef std::shared_ptr<const __detail::_NFA<_Rx_traits>> _AutomatonPtr;
+
+      void
+      _M_compile(const _Ch_type* __first, const _Ch_type* __last,
+		 flag_type __f)
+      {
+	__detail::_Compiler<_Rx_traits> __c(__first, __last, _M_loc, __f);
+	_M_automaton = __c._M_get_nfa();
+	_M_flags = __f;
+      }
+
+      template<typename _Bp, typename _Ap, typename _Cp, typename _Rp>
+	friend bool
+	__detail::__regex_algo_impl(_Bp, _Bp, match_results<_Bp, _Ap>&,
+				    const basic_regex<_Cp, _Rp>&,
+				    regex_constants::match_flag_type,
+				    __detail::_RegexExecutorPolicy, bool);
+
+      template<typename, typename, typename, bool>
+	friend class __detail::_Executor;
+
+      flag_type		_M_flags;
+      locale_type	_M_loc;
+      _AutomatonPtr	_M_automaton;
+    };
+
+#if ! __cpp_inline_variables
+  template<typename _Ch, typename _Tr>
+    constexpr regex_constants::syntax_option_type
+    basic_regex<_Ch, _Tr>::icase;
+
+  template<typename _Ch, typename _Tr>
+    constexpr regex_constants::syntax_option_type
+    basic_regex<_Ch, _Tr>::nosubs;
+
+  template<typename _Ch, typename _Tr>
+    constexpr regex_constants::syntax_option_type
+    basic_regex<_Ch, _Tr>::optimize;
+
+  template<typename _Ch, typename _Tr>
+    constexpr regex_constants::syntax_option_type
+    basic_regex<_Ch, _Tr>::collate;
+
+  template<typename _Ch, typename _Tr>
+    constexpr regex_constants::syntax_option_type
+    basic_regex<_Ch, _Tr>::ECMAScript;
+
+  template<typename _Ch, typename _Tr>
+    constexpr regex_constants::syntax_option_type
+    basic_regex<_Ch, _Tr>::basic;
+
+  template<typename _Ch, typename _Tr>
+    constexpr regex_constants::syntax_option_type
+    basic_regex<_Ch, _Tr>::extended;
+
+  template<typename _Ch, typename _Tr>
+    constexpr regex_constants::syntax_option_type
+    basic_regex<_Ch, _Tr>::awk;
+
+  template<typename _Ch, typename _Tr>
+    constexpr regex_constants::syntax_option_type
+    basic_regex<_Ch, _Tr>::grep;
+
+  template<typename _Ch, typename _Tr>
+    constexpr regex_constants::syntax_option_type
+    basic_regex<_Ch, _Tr>::egrep;
+#endif // ! C++17
+
+#if __cpp_deduction_guides >= 201606
+  template<typename _ForwardIterator>
+    basic_regex(_ForwardIterator, _ForwardIterator,
+		regex_constants::syntax_option_type = {})
+      -> basic_regex<typename iterator_traits<_ForwardIterator>::value_type>;
+#endif
+
+  /** @brief Standard regular expressions. */
+  typedef basic_regex<char>    regex;
+
+#ifdef _GLIBCXX_USE_WCHAR_T
+  /** @brief Standard wide-character regular expressions. */
+  typedef basic_regex<wchar_t> wregex;
+#endif
+
+
+  // [7.8.6] basic_regex swap
+  /**
+   * @brief Swaps the contents of two regular expression objects.
+   * @param __lhs First regular expression.
+   * @param __rhs Second regular expression.
+   * @relates basic_regex
+   */
+  template<typename _Ch_type, typename _Rx_traits>
+    inline void
+    swap(basic_regex<_Ch_type, _Rx_traits>& __lhs,
+	 basic_regex<_Ch_type, _Rx_traits>& __rhs) noexcept
+    { __lhs.swap(__rhs); }
+
+
+  // C++11 28.9 [re.submatch] Class template sub_match
+  /**
+   * A sequence of characters matched by a particular marked sub-expression.
+   *
+   * An object of this class is essentially a pair of iterators marking a
+   * matched subexpression within a regular expression pattern match. Such
+   * objects can be converted to and compared with std::basic_string objects
+   * of a similar base character type as the pattern matched by the regular
+   * expression.
+   *
+   * The iterators that make up the pair are the usual half-open interval
+   * referencing the actual original pattern matched.
+   */
+  template<typename _BiIter>
+    class sub_match : public std::pair<_BiIter, _BiIter>
+    {
+      typedef iterator_traits<_BiIter>			__iter_traits;
+	
+    public:
+      typedef typename __iter_traits::value_type      	value_type;
+      typedef typename __iter_traits::difference_type 	difference_type;
+      typedef _BiIter					iterator;
+      typedef basic_string<value_type>			string_type;
+
+      bool matched;
+
+      constexpr sub_match() noexcept : matched() { }
+
+      /// Gets the length of the matching sequence.
+      difference_type
+      length() const noexcept
+      { return this->matched ? std::distance(this->first, this->second) : 0; }
+
+      /**
+       * @brief Gets the matching sequence as a string.
+       *
+       * @returns the matching sequence as a string.
+       *
+       * This is the implicit conversion operator.  It is identical to the
+       * str() member function except that it will want to pop up in
+       * unexpected places and cause a great deal of confusion and cursing
+       * from the unwary.
+       */
+      operator string_type() const
+      { return str(); }
+
+      /**
+       * @brief Gets the matching sequence as a string.
+       *
+       * @returns the matching sequence as a string.
+       */
+      string_type
+      str() const
+      {
+	return this->matched
+	  ? string_type(this->first, this->second)
+	  : string_type();
+      }
+
+      /**
+       * @brief Compares this and another matched sequence.
+       *
+       * @param __s Another matched sequence to compare to this one.
+       *
+       * @retval negative  This matched sequence will collate before `__s`.
+       * @retval zero      This matched sequence is equivalent to `__s`.
+       * @retval positive  This matched sequence will collate after `__s`.
+       */
+      int
+      compare(const sub_match& __s) const
+      { return this->_M_str().compare(__s._M_str()); }
+
+      /**
+       * @{
+       * @brief Compares this `sub_match` to a string.
+       *
+       * @param __s A string to compare to this `sub_match`.
+       *
+       * @retval negative  This matched sequence will collate before `__s`.
+       * @retval zero      This matched sequence is equivalent to `__s`.
+       * @retval positive  This matched sequence will collate after `__s`.
+       */
+      int
+      compare(const string_type& __s) const
+      { return this->_M_str().compare(__s); }
+
+      int
+      compare(const value_type* __s) const
+      { return this->_M_str().compare(__s); }
+      /// @}
+
+      /// @cond undocumented
+      // Non-standard, used by comparison operators
+      int
+      _M_compare(const value_type* __s, size_t __n) const
+      { return this->_M_str().compare({__s, __n}); }
+      /// @endcond
+
+    private:
+      // Simplified basic_string_view for C++11
+      struct __string_view
+      {
+	using traits_type = typename string_type::traits_type;
+
+	__string_view() = default;
+
+	__string_view(const value_type* __s, size_t __n) noexcept
+	: _M_data(__s), _M_len(__n) { }
+
+	__string_view(const value_type* __s) noexcept
+	: _M_data(__s), _M_len(traits_type::length(__s)) { }
+
+	__string_view(const string_type& __s) noexcept
+	: _M_data(__s.data()), _M_len(__s.length()) { }
+
+	int
+	compare(__string_view __s) const noexcept
+	{
+	  if (const size_t __n = std::min(_M_len, __s._M_len))
+	    if (int __ret = traits_type::compare(_M_data, __s._M_data, __n))
+	      return __ret;
+	  using __limits = __gnu_cxx::__int_traits<int>;
+	  const difference_type __diff = _M_len - __s._M_len;
+	  if (__diff > __limits::__max)
+	    return __limits::__max;
+	  if (__diff < __limits::__min)
+	    return __limits::__min;
+	  return static_cast<int>(__diff);
+	}
+
+      private:
+	const value_type* _M_data = nullptr;
+	size_t _M_len = 0;
+      };
+
+      // Create a __string_view over the iterator range.
+      template<typename _Iter = _BiIter>
+	__enable_if_t<__detail::__is_contiguous_iter<_Iter>::value,
+		      __string_view>
+	_M_str() const noexcept
+	{
+	  if (this->matched)
+	    if (size_t __len = this->second - this->first)
+	      return { std::__addressof(*this->first), __len };
+	  return {};
+	}
+
+      // Create a temporary string that can be converted to __string_view.
+      template<typename _Iter = _BiIter>
+	__enable_if_t<!__detail::__is_contiguous_iter<_Iter>::value,
+		      string_type>
+	_M_str() const
+	{ return str(); }
+    };
+
+
+  /** @brief Standard regex submatch over a C-style null-terminated string. */
+  typedef sub_match<const char*>	     csub_match;
+
+  /** @brief Standard regex submatch over a standard string. */
+  typedef sub_match<string::const_iterator>  ssub_match;
+
+#ifdef _GLIBCXX_USE_WCHAR_T
+  /** @brief Regex submatch over a C-style null-terminated wide string. */
+  typedef sub_match<const wchar_t*>	  wcsub_match;
+
+  /** @brief Regex submatch over a standard wide string. */
+  typedef sub_match<wstring::const_iterator> wssub_match;
+#endif
+
+  // [7.9.2] sub_match non-member operators
+
+  /// @relates sub_match @{
+
+  /**
+   * @brief Tests the equivalence of two regular expression submatches.
+   * @param __lhs First regular expression submatch.
+   * @param __rhs Second regular expression submatch.
+   * @returns true if @a __lhs  is equivalent to @a __rhs, false otherwise.
+   */
+  template<typename _BiIter>
+    inline bool
+    operator==(const sub_match<_BiIter>& __lhs, const sub_match<_BiIter>& __rhs)
+    { return __lhs.compare(__rhs) == 0; }
+
+#if __cpp_lib_three_way_comparison
+  /**
+   * @brief Three-way comparison of two regular expression submatches.
+   * @param __lhs First regular expression submatch.
+   * @param __rhs Second regular expression submatch.
+   * @returns A value indicating whether `__lhs` is less than, equal to,
+   *	      greater than, or incomparable with `__rhs`.
+   */
+  template<typename _BiIter>
+    inline auto
+    operator<=>(const sub_match<_BiIter>& __lhs,
+		const sub_match<_BiIter>& __rhs)
+    noexcept(__detail::__is_contiguous_iter<_BiIter>::value)
+    {
+      using _Tr = char_traits<typename iterator_traits<_BiIter>::value_type>;
+      return __detail::__char_traits_cmp_cat<_Tr>(__lhs.compare(__rhs));
+    }
+#else
+  /**
+   * @brief Tests the inequivalence of two regular expression submatches.
+   * @param __lhs First regular expression submatch.
+   * @param __rhs Second regular expression submatch.
+   * @returns true if @a __lhs  is not equivalent to @a __rhs, false otherwise.
+   */
+  template<typename _BiIter>
+    inline bool
+    operator!=(const sub_match<_BiIter>& __lhs, const sub_match<_BiIter>& __rhs)
+    { return __lhs.compare(__rhs) != 0; }
+
+  /**
+   * @brief Tests the ordering of two regular expression submatches.
+   * @param __lhs First regular expression submatch.
+   * @param __rhs Second regular expression submatch.
+   * @returns true if @a __lhs precedes @a __rhs, false otherwise.
+   */
+  template<typename _BiIter>
+    inline bool
+    operator<(const sub_match<_BiIter>& __lhs, const sub_match<_BiIter>& __rhs)
+    { return __lhs.compare(__rhs) < 0; }
+
+  /**
+   * @brief Tests the ordering of two regular expression submatches.
+   * @param __lhs First regular expression submatch.
+   * @param __rhs Second regular expression submatch.
+   * @returns true if @a __lhs does not succeed @a __rhs, false otherwise.
+   */
+  template<typename _BiIter>
+    inline bool
+    operator<=(const sub_match<_BiIter>& __lhs, const sub_match<_BiIter>& __rhs)
+    { return __lhs.compare(__rhs) <= 0; }
+
+  /**
+   * @brief Tests the ordering of two regular expression submatches.
+   * @param __lhs First regular expression submatch.
+   * @param __rhs Second regular expression submatch.
+   * @returns true if @a __lhs does not precede @a __rhs, false otherwise.
+   */
+  template<typename _BiIter>
+    inline bool
+    operator>=(const sub_match<_BiIter>& __lhs, const sub_match<_BiIter>& __rhs)
+    { return __lhs.compare(__rhs) >= 0; }
+
+  /**
+   * @brief Tests the ordering of two regular expression submatches.
+   * @param __lhs First regular expression submatch.
+   * @param __rhs Second regular expression submatch.
+   * @returns true if @a __lhs succeeds @a __rhs, false otherwise.
+   */
+  template<typename _BiIter>
+    inline bool
+    operator>(const sub_match<_BiIter>& __lhs, const sub_match<_BiIter>& __rhs)
+    { return __lhs.compare(__rhs) > 0; }
+#endif // three-way comparison
+
+  /// @cond undocumented
+
+  // Alias for a basic_string that can be compared to a sub_match.
+  template<typename _Bi_iter, typename _Ch_traits, typename _Ch_alloc>
+    using __sub_match_string = basic_string<
+			      typename iterator_traits<_Bi_iter>::value_type,
+			      _Ch_traits, _Ch_alloc>;
+  /// @endcond
+
+#if ! __cpp_lib_three_way_comparison
+  /**
+   * @brief Tests the equivalence of a string and a regular expression
+   *        submatch.
+   * @param __lhs A string.
+   * @param __rhs A regular expression submatch.
+   * @returns true if @a __lhs  is equivalent to @a __rhs, false otherwise.
+   */
+  template<typename _Bi_iter, typename _Ch_traits, typename _Ch_alloc>
+    inline bool
+    operator==(const __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>& __lhs,
+	       const sub_match<_Bi_iter>& __rhs)
+    { return __rhs._M_compare(__lhs.data(), __lhs.size()) == 0; }
+
+  /**
+   * @brief Tests the inequivalence of a string and a regular expression
+   *        submatch.
+   * @param __lhs A string.
+   * @param __rhs A regular expression submatch.
+   * @returns true if @a __lhs  is not equivalent to @a __rhs, false otherwise.
+   */
+  template<typename _Bi_iter, typename _Ch_traits, typename _Ch_alloc>
+    inline bool
+    operator!=(const __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>& __lhs,
+	       const sub_match<_Bi_iter>& __rhs)
+    { return !(__lhs == __rhs); }
+
+  /**
+   * @brief Tests the ordering of a string and a regular expression submatch.
+   * @param __lhs A string.
+   * @param __rhs A regular expression submatch.
+   * @returns true if @a __lhs precedes @a __rhs, false otherwise.
+   */
+  template<typename _Bi_iter, typename _Ch_traits, typename _Ch_alloc>
+    inline bool
+    operator<(const __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>& __lhs,
+	      const sub_match<_Bi_iter>& __rhs)
+    { return __rhs._M_compare(__lhs.data(), __lhs.size()) > 0; }
+
+  /**
+   * @brief Tests the ordering of a string and a regular expression submatch.
+   * @param __lhs A string.
+   * @param __rhs A regular expression submatch.
+   * @returns true if @a __lhs succeeds @a __rhs, false otherwise.
+   */
+  template<typename _Bi_iter, typename _Ch_traits, typename _Ch_alloc>
+    inline bool
+    operator>(const __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>& __lhs,
+	      const sub_match<_Bi_iter>& __rhs)
+    { return __rhs < __lhs; }
+
+  /**
+   * @brief Tests the ordering of a string and a regular expression submatch.
+   * @param __lhs A string.
+   * @param __rhs A regular expression submatch.
+   * @returns true if @a __lhs does not precede @a __rhs, false otherwise.
+   */
+  template<typename _Bi_iter, typename _Ch_traits, typename _Ch_alloc>
+    inline bool
+    operator>=(const __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>& __lhs,
+	       const sub_match<_Bi_iter>& __rhs)
+    { return !(__lhs < __rhs); }
+
+  /**
+   * @brief Tests the ordering of a string and a regular expression submatch.
+   * @param __lhs A string.
+   * @param __rhs A regular expression submatch.
+   * @returns true if @a __lhs does not succeed @a __rhs, false otherwise.
+   */
+  template<typename _Bi_iter, typename _Ch_traits, typename _Ch_alloc>
+    inline bool
+    operator<=(const __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>& __lhs,
+	       const sub_match<_Bi_iter>& __rhs)
+    { return !(__rhs < __lhs); }
+#endif // three-way comparison
+
+  /**
+   * @brief Tests the equivalence of a regular expression submatch and a
+   *        string.
+   * @param __lhs A regular expression submatch.
+   * @param __rhs A string.
+   * @returns true if @a __lhs is equivalent to @a __rhs, false otherwise.
+   */
+  template<typename _Bi_iter, typename _Ch_traits, typename _Ch_alloc>
+    inline bool
+    operator==(const sub_match<_Bi_iter>& __lhs,
+	       const __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>& __rhs)
+    { return __lhs._M_compare(__rhs.data(), __rhs.size()) == 0; }
+
+#if __cpp_lib_three_way_comparison
+  /**
+   * @brief Three-way comparison of a regular expression submatch and a string.
+   * @param __lhs A regular expression submatch.
+   * @param __rhs A string.
+   * @returns A value indicating whether `__lhs` is less than, equal to,
+   *	      greater than, or incomparable with `__rhs`.
+   */
+  template<typename _Bi_iter, typename _Ch_traits, typename _Alloc>
+    inline auto
+    operator<=>(const sub_match<_Bi_iter>& __lhs,
+		const __sub_match_string<_Bi_iter, _Ch_traits, _Alloc>& __rhs)
+    noexcept(__detail::__is_contiguous_iter<_Bi_iter>::value)
+    {
+      return __detail::__char_traits_cmp_cat<_Ch_traits>(
+	  __lhs._M_compare(__rhs.data(), __rhs.size()));
+    }
+#else
+  /**
+   * @brief Tests the inequivalence of a regular expression submatch and a
+   *        string.
+   * @param __lhs A regular expression submatch.
+   * @param __rhs A string.
+   * @returns true if @a __lhs is not equivalent to @a __rhs, false otherwise.
+   */
+  template<typename _Bi_iter, typename _Ch_traits, typename _Ch_alloc>
+    inline bool
+    operator!=(const sub_match<_Bi_iter>& __lhs,
+	       const __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>& __rhs)
+    { return !(__lhs == __rhs); }
+
+  /**
+   * @brief Tests the ordering of a regular expression submatch and a string.
+   * @param __lhs A regular expression submatch.
+   * @param __rhs A string.
+   * @returns true if @a __lhs precedes @a __rhs, false otherwise.
+   */
+  template<typename _Bi_iter, typename _Ch_traits, typename _Ch_alloc>
+    inline bool
+    operator<(const sub_match<_Bi_iter>& __lhs,
+	      const __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>& __rhs)
+    { return __lhs._M_compare(__rhs.data(), __rhs.size()) < 0; }
+
+  /**
+   * @brief Tests the ordering of a regular expression submatch and a string.
+   * @param __lhs A regular expression submatch.
+   * @param __rhs A string.
+   * @returns true if @a __lhs succeeds @a __rhs, false otherwise.
+   */
+  template<typename _Bi_iter, typename _Ch_traits, typename _Ch_alloc>
+    inline bool
+    operator>(const sub_match<_Bi_iter>& __lhs,
+	      const __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>& __rhs)
+    { return __rhs < __lhs; }
+
+  /**
+   * @brief Tests the ordering of a regular expression submatch and a string.
+   * @param __lhs A regular expression submatch.
+   * @param __rhs A string.
+   * @returns true if @a __lhs does not precede @a __rhs, false otherwise.
+   */
+  template<typename _Bi_iter, typename _Ch_traits, typename _Ch_alloc>
+    inline bool
+    operator>=(const sub_match<_Bi_iter>& __lhs,
+	       const __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>& __rhs)
+    { return !(__lhs < __rhs); }
+
+  /**
+   * @brief Tests the ordering of a regular expression submatch and a string.
+   * @param __lhs A regular expression submatch.
+   * @param __rhs A string.
+   * @returns true if @a __lhs does not succeed @a __rhs, false otherwise.
+   */
+  template<typename _Bi_iter, typename _Ch_traits, typename _Ch_alloc>
+    inline bool
+    operator<=(const sub_match<_Bi_iter>& __lhs,
+	       const __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>& __rhs)
+    { return !(__rhs < __lhs); }
+
+  /**
+   * @brief Tests the equivalence of a C string and a regular expression
+   *        submatch.
+   * @param __lhs A null-terminated string.
+   * @param __rhs A regular expression submatch.
+   * @returns true if @a __lhs  is equivalent to @a __rhs, false otherwise.
+   */
+  template<typename _Bi_iter>
+    inline bool
+    operator==(typename iterator_traits<_Bi_iter>::value_type const* __lhs,
+	       const sub_match<_Bi_iter>& __rhs)
+    { return __rhs.compare(__lhs) == 0; }
+
+  /**
+   * @brief Tests the inequivalence of a C string and a regular
+   *        expression submatch.
+   * @param __lhs A null-terminated string.
+   * @param __rhs A regular expression submatch.
+   * @returns true if @a __lhs is not equivalent to @a __rhs, false otherwise.
+   */
+  template<typename _Bi_iter>
+    inline bool
+    operator!=(typename iterator_traits<_Bi_iter>::value_type const* __lhs,
+	       const sub_match<_Bi_iter>& __rhs)
+    { return !(__lhs == __rhs); }
+
+  /**
+   * @brief Tests the ordering of a C string and a regular expression submatch.
+   * @param __lhs A null-terminated string.
+   * @param __rhs A regular expression submatch.
+   * @returns true if @a __lhs precedes @a __rhs, false otherwise.
+   */
+  template<typename _Bi_iter>
+    inline bool
+    operator<(typename iterator_traits<_Bi_iter>::value_type const* __lhs,
+	      const sub_match<_Bi_iter>& __rhs)
+    { return __rhs.compare(__lhs) > 0; }
+
+  /**
+   * @brief Tests the ordering of a C string and a regular expression submatch.
+   * @param __lhs A null-terminated string.
+   * @param __rhs A regular expression submatch.
+   * @returns true if @a __lhs succeeds @a __rhs, false otherwise.
+   */
+  template<typename _Bi_iter>
+    inline bool
+    operator>(typename iterator_traits<_Bi_iter>::value_type const* __lhs,
+	      const sub_match<_Bi_iter>& __rhs)
+    { return __rhs < __lhs; }
+
+  /**
+   * @brief Tests the ordering of a C string and a regular expression submatch.
+   * @param __lhs A null-terminated string.
+   * @param __rhs A regular expression submatch.
+   * @returns true if @a __lhs does not precede @a __rhs, false otherwise.
+   */
+  template<typename _Bi_iter>
+    inline bool
+    operator>=(typename iterator_traits<_Bi_iter>::value_type const* __lhs,
+	       const sub_match<_Bi_iter>& __rhs)
+    { return !(__lhs < __rhs); }
+
+  /**
+   * @brief Tests the ordering of a C string and a regular expression submatch.
+   * @param __lhs A null-terminated string.
+   * @param __rhs A regular expression submatch.
+   * @returns true if @a __lhs does not succeed @a __rhs, false otherwise.
+   */
+  template<typename _Bi_iter>
+    inline bool
+    operator<=(typename iterator_traits<_Bi_iter>::value_type const* __lhs,
+	       const sub_match<_Bi_iter>& __rhs)
+    { return !(__rhs < __lhs); }
+#endif // three-way comparison
+
+  /**
+   * @brief Tests the equivalence of a regular expression submatch and a C
+   *        string.
+   * @param __lhs A regular expression submatch.
+   * @param __rhs A null-terminated string.
+   * @returns true if @a __lhs  is equivalent to @a __rhs, false otherwise.
+   */
+  template<typename _Bi_iter>
+    inline bool
+    operator==(const sub_match<_Bi_iter>& __lhs,
+	       typename iterator_traits<_Bi_iter>::value_type const* __rhs)
+    { return __lhs.compare(__rhs) == 0; }
+
+#if __cpp_lib_three_way_comparison
+  /**
+   * @brief Three-way comparison of a regular expression submatch and a C
+   *	    string.
+   * @param __lhs A regular expression submatch.
+   * @param __rhs A null-terminated string.
+   * @returns A value indicating whether `__lhs` is less than, equal to,
+   *	      greater than, or incomparable with `__rhs`.
+   */
+  template<typename _Bi_iter>
+    inline auto
+    operator<=>(const sub_match<_Bi_iter>& __lhs,
+		typename iterator_traits<_Bi_iter>::value_type const* __rhs)
+    noexcept(__detail::__is_contiguous_iter<_Bi_iter>::value)
+    {
+      using _Tr = char_traits<typename iterator_traits<_Bi_iter>::value_type>;
+      return __detail::__char_traits_cmp_cat<_Tr>(__lhs.compare(__rhs));
+    }
+#else
+  /**
+   * @brief Tests the inequivalence of a regular expression submatch and a
+   *        string.
+   * @param __lhs A regular expression submatch.
+   * @param __rhs A null-terminated string.
+   * @returns true if @a __lhs is not equivalent to @a __rhs, false otherwise.
+   */
+  template<typename _Bi_iter>
+    inline bool
+    operator!=(const sub_match<_Bi_iter>& __lhs,
+	       typename iterator_traits<_Bi_iter>::value_type const* __rhs)
+    { return !(__lhs == __rhs); }
+
+  /**
+   * @brief Tests the ordering of a regular expression submatch and a C string.
+   * @param __lhs A regular expression submatch.
+   * @param __rhs A null-terminated string.
+   * @returns true if @a __lhs precedes @a __rhs, false otherwise.
+   */
+  template<typename _Bi_iter>
+    inline bool
+    operator<(const sub_match<_Bi_iter>& __lhs,
+	      typename iterator_traits<_Bi_iter>::value_type const* __rhs)
+    { return __lhs.compare(__rhs) < 0; }
+
+  /**
+   * @brief Tests the ordering of a regular expression submatch and a C string.
+   * @param __lhs A regular expression submatch.
+   * @param __rhs A null-terminated string.
+   * @returns true if @a __lhs succeeds @a __rhs, false otherwise.
+   */
+  template<typename _Bi_iter>
+    inline bool
+    operator>(const sub_match<_Bi_iter>& __lhs,
+	      typename iterator_traits<_Bi_iter>::value_type const* __rhs)
+    { return __rhs < __lhs; }
+
+  /**
+   * @brief Tests the ordering of a regular expression submatch and a C string.
+   * @param __lhs A regular expression submatch.
+   * @param __rhs A null-terminated string.
+   * @returns true if @a __lhs does not precede @a __rhs, false otherwise.
+   */
+  template<typename _Bi_iter>
+    inline bool
+    operator>=(const sub_match<_Bi_iter>& __lhs,
+	       typename iterator_traits<_Bi_iter>::value_type const* __rhs)
+    { return !(__lhs < __rhs); }
+
+  /**
+   * @brief Tests the ordering of a regular expression submatch and a C string.
+   * @param __lhs A regular expression submatch.
+   * @param __rhs A null-terminated string.
+   * @returns true if @a __lhs does not succeed @a __rhs, false otherwise.
+   */
+  template<typename _Bi_iter>
+    inline bool
+    operator<=(const sub_match<_Bi_iter>& __lhs,
+	       typename iterator_traits<_Bi_iter>::value_type const* __rhs)
+    { return !(__rhs < __lhs); }
+
+  /**
+   * @brief Tests the equivalence of a character and a regular expression
+   *        submatch.
+   * @param __lhs A character.
+   * @param __rhs A regular expression submatch.
+   * @returns true if @a __lhs is equivalent to @a __rhs, false otherwise.
+   */
+  template<typename _Bi_iter>
+    inline bool
+    operator==(typename iterator_traits<_Bi_iter>::value_type const& __lhs,
+	       const sub_match<_Bi_iter>& __rhs)
+    { return __rhs._M_compare(std::__addressof(__lhs), 1) == 0; }
+
+  /**
+   * @brief Tests the inequivalence of a character and a regular expression
+   *        submatch.
+   * @param __lhs A character.
+   * @param __rhs A regular expression submatch.
+   * @returns true if @a __lhs is not equivalent to @a __rhs, false otherwise.
+   */
+  template<typename _Bi_iter>
+    inline bool
+    operator!=(typename iterator_traits<_Bi_iter>::value_type const& __lhs,
+	       const sub_match<_Bi_iter>& __rhs)
+    { return !(__lhs == __rhs); }
+
+  /**
+   * @brief Tests the ordering of a character and a regular expression
+   *        submatch.
+   * @param __lhs A character.
+   * @param __rhs A regular expression submatch.
+   * @returns true if @a __lhs precedes @a __rhs, false otherwise.
+   */
+  template<typename _Bi_iter>
+    inline bool
+    operator<(typename iterator_traits<_Bi_iter>::value_type const& __lhs,
+	      const sub_match<_Bi_iter>& __rhs)
+    { return __rhs._M_compare(std::__addressof(__lhs), 1) > 0; }
+
+  /**
+   * @brief Tests the ordering of a character and a regular expression
+   *        submatch.
+   * @param __lhs A character.
+   * @param __rhs A regular expression submatch.
+   * @returns true if @a __lhs succeeds @a __rhs, false otherwise.
+   */
+  template<typename _Bi_iter>
+    inline bool
+    operator>(typename iterator_traits<_Bi_iter>::value_type const& __lhs,
+	      const sub_match<_Bi_iter>& __rhs)
+    { return __rhs < __lhs; }
+
+  /**
+   * @brief Tests the ordering of a character and a regular expression
+   *        submatch.
+   * @param __lhs A character.
+   * @param __rhs A regular expression submatch.
+   * @returns true if @a __lhs does not precede @a __rhs, false otherwise.
+   */
+  template<typename _Bi_iter>
+    inline bool
+    operator>=(typename iterator_traits<_Bi_iter>::value_type const& __lhs,
+	       const sub_match<_Bi_iter>& __rhs)
+    { return !(__lhs < __rhs); }
+
+  /**
+   * @brief Tests the ordering of a character and a regular expression
+   *        submatch.
+   * @param __lhs A character.
+   * @param __rhs A regular expression submatch.
+   * @returns true if @a __lhs does not succeed @a __rhs, false otherwise.
+   */
+  template<typename _Bi_iter>
+    inline bool
+    operator<=(typename iterator_traits<_Bi_iter>::value_type const& __lhs,
+	       const sub_match<_Bi_iter>& __rhs)
+    { return !(__rhs < __lhs); }
+#endif // three-way comparison
+
+  /**
+   * @brief Tests the equivalence of a regular expression submatch and a
+   *        character.
+   * @param __lhs A regular expression submatch.
+   * @param __rhs A character.
+   * @returns true if @a __lhs  is equivalent to @a __rhs, false otherwise.
+   */
+  template<typename _Bi_iter>
+    inline bool
+    operator==(const sub_match<_Bi_iter>& __lhs,
+	       typename iterator_traits<_Bi_iter>::value_type const& __rhs)
+    { return __lhs._M_compare(std::__addressof(__rhs), 1) == 0; }
+
+#if __cpp_lib_three_way_comparison
+  /**
+   * @brief Three-way comparison of a regular expression submatch and a
+   *	    character.
+   * @param __lhs A regular expression submatch.
+   * @param __rhs A character.
+   * @returns A value indicating whether `__lhs` is less than, equal to,
+   *	      greater than, or incomparable with `__rhs`.
+   */
+
+  template<typename _Bi_iter>
+    inline auto
+    operator<=>(const sub_match<_Bi_iter>& __lhs,
+		typename iterator_traits<_Bi_iter>::value_type const& __rhs)
+    noexcept(__detail::__is_contiguous_iter<_Bi_iter>::value)
+    {
+      using _Tr = char_traits<typename iterator_traits<_Bi_iter>::value_type>;
+      return __detail::__char_traits_cmp_cat<_Tr>(
+	  __lhs._M_compare(std::__addressof(__rhs), 1));
+    }
+#else
+  /**
+   * @brief Tests the inequivalence of a regular expression submatch and a
+   *        character.
+   * @param __lhs A regular expression submatch.
+   * @param __rhs A character.
+   * @returns true if @a __lhs is not equivalent to @a __rhs, false otherwise.
+   */
+  template<typename _Bi_iter>
+    inline bool
+    operator!=(const sub_match<_Bi_iter>& __lhs,
+	       typename iterator_traits<_Bi_iter>::value_type const& __rhs)
+    { return !(__lhs == __rhs); }
+
+  /**
+   * @brief Tests the ordering of a regular expression submatch and a
+   *        character.
+   * @param __lhs A regular expression submatch.
+   * @param __rhs A character.
+   * @returns true if @a __lhs precedes @a __rhs, false otherwise.
+   */
+  template<typename _Bi_iter>
+    inline bool
+    operator<(const sub_match<_Bi_iter>& __lhs,
+	      typename iterator_traits<_Bi_iter>::value_type const& __rhs)
+    { return __lhs._M_compare(std::__addressof(__rhs), 1) < 0; }
+
+  /**
+   * @brief Tests the ordering of a regular expression submatch and a
+   *        character.
+   * @param __lhs A regular expression submatch.
+   * @param __rhs A character.
+   * @returns true if @a __lhs succeeds @a __rhs, false otherwise.
+   */
+  template<typename _Bi_iter>
+    inline bool
+    operator>(const sub_match<_Bi_iter>& __lhs,
+	      typename iterator_traits<_Bi_iter>::value_type const& __rhs)
+    { return __rhs < __lhs; }
+
+  /**
+   * @brief Tests the ordering of a regular expression submatch and a
+   *        character.
+   * @param __lhs A regular expression submatch.
+   * @param __rhs A character.
+   * @returns true if @a __lhs does not precede @a __rhs, false otherwise.
+   */
+  template<typename _Bi_iter>
+    inline bool
+    operator>=(const sub_match<_Bi_iter>& __lhs,
+	       typename iterator_traits<_Bi_iter>::value_type const& __rhs)
+    { return !(__lhs < __rhs); }
+
+  /**
+   * @brief Tests the ordering of a regular expression submatch and a
+   *        character.
+   * @param __lhs A regular expression submatch.
+   * @param __rhs A character.
+   * @returns true if @a __lhs does not succeed @a __rhs, false otherwise.
+   */
+  template<typename _Bi_iter>
+    inline bool
+    operator<=(const sub_match<_Bi_iter>& __lhs,
+	       typename iterator_traits<_Bi_iter>::value_type const& __rhs)
+    { return !(__rhs < __lhs); }
+#endif // three-way comparison
+
+  /**
+   * @brief Inserts a matched string into an output stream.
+   *
+   * @param __os The output stream.
+   * @param __m  A submatch string.
+   *
+   * @returns the output stream with the submatch string inserted.
+   */
+  template<typename _Ch_type, typename _Ch_traits, typename _Bi_iter>
+    inline
+    basic_ostream<_Ch_type, _Ch_traits>&
+    operator<<(basic_ostream<_Ch_type, _Ch_traits>& __os,
+	       const sub_match<_Bi_iter>& __m)
+    { return __os << __m.str(); }
+
+  /// @} relates sub_match
+
+  // [7.10] Class template match_results
+
+  /**
+   * @brief The results of a match or search operation.
+   *
+   * A collection of character sequences representing the result of a regular
+   * expression match.  Storage for the collection is allocated and freed as
+   * necessary by the member functions of class template match_results.
+   *
+   * This class satisfies the Sequence requirements, with the exception that
+   * only the operations defined for a const-qualified Sequence are supported.
+   *
+   * The sub_match object stored at index 0 represents sub-expression 0, i.e.
+   * the whole match. In this case the %sub_match member matched is always true.
+   * The sub_match object stored at index n denotes what matched the marked
+   * sub-expression n within the matched expression. If the sub-expression n
+   * participated in a regular expression match then the %sub_match member
+   * matched evaluates to true, and members first and second denote the range
+   * of characters [first, second) which formed that match. Otherwise matched
+   * is false, and members first and second point to the end of the sequence
+   * that was searched.
+   */
+  template<typename _Bi_iter,
+	   typename _Alloc = allocator<sub_match<_Bi_iter> > >
+    class match_results
+    : private std::vector<sub_match<_Bi_iter>, _Alloc>
+    {
+    private:
+      /*
+       * The vector base is empty if this does not represent a match (!ready());
+       * Otherwise if it's a match failure, it contains 3 elements:
+       * [0] unmatched
+       * [1] prefix
+       * [2] suffix
+       * Otherwise it contains n+4 elements where n is the number of marked
+       * sub-expressions:
+       * [0] entire match
+       * [1] 1st marked subexpression
+       * ...
+       * [n] nth marked subexpression
+       * [n+1] unmatched
+       * [n+2] prefix
+       * [n+3] suffix
+       */
+      typedef std::vector<sub_match<_Bi_iter>, _Alloc>     _Base_type;
+      // In debug mode _Base_type is the debug vector, this is the unsafe one:
+      typedef _GLIBCXX_STD_C::vector<sub_match<_Bi_iter>, _Alloc> _Unchecked;
+      typedef std::iterator_traits<_Bi_iter>   	   	   __iter_traits;
+      typedef regex_constants::match_flag_type		   match_flag_type;
+
+    public:
+      /**
+       * @name 28.10 Public Types
+       */
+      ///@{
+      typedef sub_match<_Bi_iter>			   value_type;
+      typedef const value_type&				   const_reference;
+      typedef value_type&				   reference;
+      typedef typename _Base_type::const_iterator	   const_iterator;
+      typedef const_iterator				   iterator;
+      typedef typename __iter_traits::difference_type	   difference_type;
+      typedef typename allocator_traits<_Alloc>::size_type size_type;
+      typedef _Alloc					   allocator_type;
+      typedef typename __iter_traits::value_type 	   char_type;
+      typedef std::basic_string<char_type>		   string_type;
+      ///@}
+
+    public:
+      /**
+       * @name 28.10.1 Construction, Copying, and Destruction
+       */
+      ///@{
+
+      /**
+       * @brief Constructs a default %match_results container.
+       * @post size() returns 0 and str() returns an empty string.
+       */
+      match_results() : match_results(_Alloc()) { }
+
+      /**
+       * @brief Constructs a default %match_results container.
+       * @post size() returns 0 and str() returns an empty string.
+       */
+      explicit
+      match_results(const _Alloc& __a) noexcept
+      : _Base_type(__a)
+      { }
+
+      /**
+       * @brief Copy constructs a %match_results.
+       */
+      match_results(const match_results&) = default;
+
+      /**
+       * @brief Move constructs a %match_results.
+       */
+      match_results(match_results&&) noexcept = default;
+
+      /**
+       * @brief Assigns rhs to *this.
+       */
+      match_results&
+      operator=(const match_results&) = default;
+
+      /**
+       * @brief Move-assigns rhs to *this.
+       */
+      match_results&
+      operator=(match_results&&) = default;
+
+      /**
+       * @brief Destroys a %match_results object.
+       */
+      ~match_results() = default;
+
+      ///@}
+
+      // 28.10.2, state:
+      /**
+       * @brief Indicates if the %match_results is ready.
+       * @retval true   The object has a fully-established result state.
+       * @retval false  The object is not ready.
+       */
+      bool ready() const noexcept { return !_Unchecked::empty(); }
+
+      /**
+       * @name 28.10.2 Size
+       */
+      ///@{
+
+      /**
+       * @brief Gets the number of matches and submatches.
+       *
+       * The number of matches for a given regular expression will be either 0
+       * if there was no match or mark_count() + 1 if a match was successful.
+       * Some matches may be empty.
+       *
+       * @returns the number of matches found.
+       */
+      size_type
+      size() const noexcept
+      { return _Unchecked::empty() ? 0 : _Unchecked::size() - 3; }
+
+      size_type
+      max_size() const noexcept
+      { return _Unchecked::max_size() - 3; }
+
+      /**
+       * @brief Indicates if the %match_results contains no results.
+       * @retval true The %match_results object is empty.
+       * @retval false The %match_results object is not empty.
+       */
+      _GLIBCXX_NODISCARD bool
+      empty() const noexcept
+      { return _Unchecked::size() <= 3; }
+
+      ///@}
+
+      /**
+       * @name 28.10.4 Element Access
+       */
+      ///@{
+
+      /**
+       * @brief Gets the length of the indicated submatch.
+       * @param __sub indicates the submatch.
+       * @pre   ready() == true
+       *
+       * This function returns the length of the indicated submatch, or the
+       * length of the entire match if @p __sub is zero (the default).
+       */
+      difference_type
+      length(size_type __sub = 0) const
+      { return (*this)[__sub].length(); }
+
+      /**
+       * @brief Gets the offset of the beginning of the indicated submatch.
+       * @param __sub indicates the submatch.
+       * @pre   ready() == true
+       *
+       * This function returns the offset from the beginning of the target
+       * sequence to the beginning of the submatch, unless the value of @p __sub
+       * is zero (the default), in which case this function returns the offset
+       * from the beginning of the target sequence to the beginning of the
+       * match.
+       */
+      difference_type
+      position(size_type __sub = 0) const
+      { return std::distance(_M_begin, (*this)[__sub].first); }
+
+      /**
+       * @brief Gets the match or submatch converted to a string type.
+       * @param __sub indicates the submatch.
+       * @pre   ready() == true
+       *
+       * This function gets the submatch (or match, if @p __sub is
+       * zero) extracted from the target range and converted to the
+       * associated string type.
+       */
+      string_type
+      str(size_type __sub = 0) const
+      { return string_type((*this)[__sub]); }
+
+      /**
+       * @brief Gets a %sub_match reference for the match or submatch.
+       * @param __sub indicates the submatch.
+       * @pre   ready() == true
+       *
+       * This function gets a reference to the indicated submatch, or
+       * the entire match if @p __sub is zero.
+       *
+       * If @p __sub >= size() then this function returns a %sub_match with a
+       * special value indicating no submatch.
+       */
+      const_reference
+      operator[](size_type __sub) const
+      {
+	__glibcxx_assert( ready() );
+	return __sub < size()
+	       ? _Unchecked::operator[](__sub)
+	       : _M_unmatched_sub();
+      }
+
+      /**
+       * @brief Gets a %sub_match representing the match prefix.
+       * @pre   ready() == true
+       *
+       * This function gets a reference to a %sub_match object representing the
+       * part of the target range between the start of the target range and the
+       * start of the match.
+       */
+      const_reference
+      prefix() const
+      {
+	__glibcxx_assert( ready() );
+	return !empty() ? _M_prefix() : _M_unmatched_sub();
+      }
+
+      /**
+       * @brief Gets a %sub_match representing the match suffix.
+       * @pre   ready() == true
+       *
+       * This function gets a reference to a %sub_match object representing the
+       * part of the target range between the end of the match and the end of
+       * the target range.
+       */
+      const_reference
+      suffix() const
+      {
+	__glibcxx_assert( ready() );
+	return !empty() ? _M_suffix() : _M_unmatched_sub();
+      }
+
+      /**
+       * @brief Gets an iterator to the start of the %sub_match collection.
+       */
+      const_iterator
+      begin() const noexcept
+      { return _Base_type::begin(); }
+
+      /**
+       * @brief Gets an iterator to the start of the %sub_match collection.
+       */
+      const_iterator
+      cbegin() const noexcept
+      { return this->begin(); }
+
+      /**
+       * @brief Gets an iterator to one-past-the-end of the collection.
+       */
+      const_iterator
+      end() const noexcept
+      { return _Base_type::end() - (_Base_type::empty() ? 0 : 3); }
+
+      /**
+       * @brief Gets an iterator to one-past-the-end of the collection.
+       */
+      const_iterator
+      cend() const noexcept
+      { return this->end(); }
+
+      ///@}
+
+      /**
+       * @name 28.10.5 Formatting
+       *
+       * These functions perform formatted substitution of the matched
+       * character sequences into their target.  The format specifiers and
+       * escape sequences accepted by these functions are determined by
+       * their @p flags parameter as documented above.
+       */
+       ///@{
+
+      /**
+       * @pre   ready() == true
+       */
+      template<typename _Out_iter>
+	_Out_iter
+	format(_Out_iter __out, const char_type* __fmt_first,
+	       const char_type* __fmt_last,
+	       match_flag_type __flags = regex_constants::format_default) const;
+
+      /**
+       * @pre   ready() == true
+       */
+      template<typename _Out_iter, typename _St, typename _Sa>
+	_Out_iter
+	format(_Out_iter __out, const basic_string<char_type, _St, _Sa>& __fmt,
+	       match_flag_type __flags = regex_constants::format_default) const
+	{
+	  return format(__out, __fmt.data(), __fmt.data() + __fmt.size(),
+			__flags);
+	}
+
+      /**
+       * @pre   ready() == true
+       */
+      template<typename _St, typename _Sa>
+	basic_string<char_type, _St, _Sa>
+	format(const basic_string<char_type, _St, _Sa>& __fmt,
+	       match_flag_type __flags = regex_constants::format_default) const
+	{
+	  basic_string<char_type, _St, _Sa> __result;
+	  format(std::back_inserter(__result), __fmt, __flags);
+	  return __result;
+	}
+
+      /**
+       * @pre   ready() == true
+       */
+      string_type
+      format(const char_type* __fmt,
+	     match_flag_type __flags = regex_constants::format_default) const
+      {
+	string_type __result;
+	format(std::back_inserter(__result),
+	       __fmt,
+	       __fmt + char_traits<char_type>::length(__fmt),
+	       __flags);
+	return __result;
+      }
+
+      ///@}
+
+      /**
+       * @name 28.10.6 Allocator
+       */
+      ///@{
+
+      /**
+       * @brief Gets a copy of the allocator.
+       */
+      allocator_type
+      get_allocator() const noexcept
+      { return _Base_type::get_allocator(); }
+
+      ///@}
+
+      /**
+       * @name 28.10.7 Swap
+       */
+       ///@{
+
+      /**
+       * @brief Swaps the contents of two match_results.
+       */
+      void
+      swap(match_results& __that) noexcept
+      {
+	using std::swap;
+	_Base_type::swap(__that);
+	swap(_M_begin, __that._M_begin);
+      }
+      ///@}
+
+    private:
+      template<typename, typename, typename>
+	friend class regex_iterator;
+
+      /// @cond undocumented
+
+      template<typename, typename, typename, bool>
+	friend class __detail::_Executor;
+
+      template<typename _Bp, typename _Ap, typename _Cp, typename _Rp>
+	friend bool
+	__detail::__regex_algo_impl(_Bp, _Bp, match_results<_Bp, _Ap>&,
+				    const basic_regex<_Cp, _Rp>&,
+				    regex_constants::match_flag_type,
+				    __detail::_RegexExecutorPolicy, bool);
+
+      // Reset contents to __size unmatched sub_match objects
+      // (plus additional objects for prefix, suffix and unmatched sub).
+      void
+      _M_resize(unsigned int __size)
+      { _Unchecked::assign(__size + 3, sub_match<_Bi_iter>{}); }
+
+      // Set state to a failed match for the given past-the-end iterator.
+      void
+      _M_establish_failed_match(_Bi_iter __end)
+      {
+	sub_match<_Bi_iter> __sm;
+	__sm.first = __sm.second = __end;
+	_Unchecked::assign(3, __sm);
+      }
+
+      const_reference
+      _M_unmatched_sub() const
+      { return _Unchecked::operator[](_Unchecked::size() - 3); }
+
+      sub_match<_Bi_iter>&
+      _M_unmatched_sub()
+      { return _Unchecked::operator[](_Unchecked::size() - 3); }
+
+      const_reference
+      _M_prefix() const
+      { return _Unchecked::operator[](_Unchecked::size() - 2); }
+
+      sub_match<_Bi_iter>&
+      _M_prefix()
+      { return _Unchecked::operator[](_Unchecked::size() - 2); }
+
+      const_reference
+      _M_suffix() const
+      { return _Unchecked::operator[](_Unchecked::size() - 1); }
+
+      sub_match<_Bi_iter>&
+      _M_suffix()
+      { return _Unchecked::operator[](_Unchecked::size() - 1); }
+
+      _Bi_iter _M_begin {};
+      /// @endcond
+    };
+
+  typedef match_results<const char*>		 cmatch;
+  typedef match_results<string::const_iterator>	 smatch;
+#ifdef _GLIBCXX_USE_WCHAR_T
+  typedef match_results<const wchar_t*>		 wcmatch;
+  typedef match_results<wstring::const_iterator> wsmatch;
+#endif
+
+  // match_results comparisons
+
+  /**
+   * @brief Compares two match_results for equality.
+   * @returns true if the two objects refer to the same match,
+   *          false otherwise.
+   */
+  template<typename _Bi_iter, typename _Alloc>
+    inline bool
+    operator==(const match_results<_Bi_iter, _Alloc>& __m1,
+	       const match_results<_Bi_iter, _Alloc>& __m2)
+    {
+      if (__m1.ready() != __m2.ready())
+	return false;
+      if (!__m1.ready())  // both are not ready
+	return true;
+      if (__m1.empty() != __m2.empty())
+	return false;
+      if (__m1.empty())   // both are empty
+	return true;
+      return __m1.prefix() == __m2.prefix()
+	&& __m1.size() == __m2.size()
+	&& std::equal(__m1.begin(), __m1.end(), __m2.begin())
+	&& __m1.suffix() == __m2.suffix();
+    }
+
+#if ! __cpp_lib_three_way_comparison
+  /**
+   * @brief Compares two match_results for inequality.
+   * @returns true if the two objects do not refer to the same match,
+   *          false otherwise.
+   */
+  template<typename _Bi_iter, class _Alloc>
+    inline bool
+    operator!=(const match_results<_Bi_iter, _Alloc>& __m1,
+	       const match_results<_Bi_iter, _Alloc>& __m2)
+    { return !(__m1 == __m2); }
+#endif
+
+  // [7.10.6] match_results swap
+  /**
+   * @brief Swaps two match results.
+   * @param __lhs A match result.
+   * @param __rhs A match result.
+   *
+   * The contents of the two match_results objects are swapped.
+   */
+  template<typename _Bi_iter, typename _Alloc>
+    inline void
+    swap(match_results<_Bi_iter, _Alloc>& __lhs,
+	 match_results<_Bi_iter, _Alloc>& __rhs) noexcept
+    { __lhs.swap(__rhs); }
+
+_GLIBCXX_END_NAMESPACE_CXX11
+
+  // [28.11.2] Function template regex_match
+  /**
+   * @name Matching, Searching, and Replacing
+   */
+  ///@{
+
+  /**
+   * @brief Determines if there is a match between the regular expression @p e
+   * and all of the character sequence [first, last).
+   *
+   * @param __s     Start of the character sequence to match.
+   * @param __e     One-past-the-end of the character sequence to match.
+   * @param __m     The match results.
+   * @param __re    The regular expression.
+   * @param __flags Controls how the regular expression is matched.
+   *
+   * @retval true  A match exists.
+   * @retval false Otherwise.
+   *
+   * @throws an exception of type regex_error.
+   */
+  template<typename _Bi_iter, typename _Alloc,
+	   typename _Ch_type, typename _Rx_traits>
+    inline bool
+    regex_match(_Bi_iter				 __s,
+		_Bi_iter				 __e,
+		match_results<_Bi_iter, _Alloc>&	 __m,
+		const basic_regex<_Ch_type, _Rx_traits>& __re,
+		regex_constants::match_flag_type	 __flags
+			       = regex_constants::match_default)
+    {
+      return __detail::__regex_algo_impl(__s, __e, __m, __re, __flags,
+	__detail::_RegexExecutorPolicy::_S_auto, true);
+    }
+
+  /**
+   * @brief Indicates if there is a match between the regular expression @p e
+   * and all of the character sequence [first, last).
+   *
+   * @param __first Beginning of the character sequence to match.
+   * @param __last  One-past-the-end of the character sequence to match.
+   * @param __re    The regular expression.
+   * @param __flags Controls how the regular expression is matched.
+   *
+   * @retval true  A match exists.
+   * @retval false Otherwise.
+   *
+   * @throws an exception of type regex_error.
+   */
+  template<typename _Bi_iter, typename _Ch_type, typename _Rx_traits>
+    inline bool
+    regex_match(_Bi_iter __first, _Bi_iter __last,
+		const basic_regex<_Ch_type, _Rx_traits>& __re,
+		regex_constants::match_flag_type __flags
+		= regex_constants::match_default)
+    {
+      match_results<_Bi_iter> __what;
+      return regex_match(__first, __last, __what, __re, __flags);
+    }
+
+  /**
+   * @brief Determines if there is a match between the regular expression @p e
+   * and a C-style null-terminated string.
+   *
+   * @param __s  The C-style null-terminated string to match.
+   * @param __m  The match results.
+   * @param __re The regular expression.
+   * @param __f  Controls how the regular expression is matched.
+   *
+   * @retval true  A match exists.
+   * @retval false Otherwise.
+   *
+   * @throws an exception of type regex_error.
+   */
+  template<typename _Ch_type, typename _Alloc, typename _Rx_traits>
+    inline bool
+    regex_match(const _Ch_type* __s,
+		match_results<const _Ch_type*, _Alloc>& __m,
+		const basic_regex<_Ch_type, _Rx_traits>& __re,
+		regex_constants::match_flag_type __f
+		= regex_constants::match_default)
+    { return regex_match(__s, __s + _Rx_traits::length(__s), __m, __re, __f); }
+
+  /**
+   * @brief Determines if there is a match between the regular expression @p e
+   * and a string.
+   *
+   * @param __s     The string to match.
+   * @param __m     The match results.
+   * @param __re    The regular expression.
+   * @param __flags Controls how the regular expression is matched.
+   *
+   * @retval true  A match exists.
+   * @retval false Otherwise.
+   *
+   * @throws an exception of type regex_error.
+   */
+  template<typename _Ch_traits, typename _Ch_alloc,
+	   typename _Alloc, typename _Ch_type, typename _Rx_traits>
+    inline bool
+    regex_match(const basic_string<_Ch_type, _Ch_traits, _Ch_alloc>& __s,
+		match_results<typename basic_string<_Ch_type,
+		_Ch_traits, _Ch_alloc>::const_iterator, _Alloc>& __m,
+		const basic_regex<_Ch_type, _Rx_traits>& __re,
+		regex_constants::match_flag_type __flags
+		= regex_constants::match_default)
+    { return regex_match(__s.begin(), __s.end(), __m, __re, __flags); }
+
+  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+  // 2329. regex_match() with match_results should forbid temporary strings
+  /// Prevent unsafe attempts to get match_results from a temporary string.
+  template<typename _Ch_traits, typename _Ch_alloc,
+	   typename _Alloc, typename _Ch_type, typename _Rx_traits>
+    bool
+    regex_match(const basic_string<_Ch_type, _Ch_traits, _Ch_alloc>&&,
+		match_results<typename basic_string<_Ch_type,
+		_Ch_traits, _Ch_alloc>::const_iterator, _Alloc>&,
+		const basic_regex<_Ch_type, _Rx_traits>&,
+		regex_constants::match_flag_type
+		= regex_constants::match_default) = delete;
+
+  /**
+   * @brief Indicates if there is a match between the regular expression @p e
+   * and a C-style null-terminated string.
+   *
+   * @param __s  The C-style null-terminated string to match.
+   * @param __re The regular expression.
+   * @param __f  Controls how the regular expression is matched.
+   *
+   * @retval true  A match exists.
+   * @retval false Otherwise.
+   *
+   * @throws an exception of type regex_error.
+   */
+  template<typename _Ch_type, class _Rx_traits>
+    inline bool
+    regex_match(const _Ch_type* __s,
+		const basic_regex<_Ch_type, _Rx_traits>& __re,
+		regex_constants::match_flag_type __f
+		= regex_constants::match_default)
+    { return regex_match(__s, __s + _Rx_traits::length(__s), __re, __f); }
+
+  /**
+   * @brief Indicates if there is a match between the regular expression @p e
+   * and a string.
+   *
+   * @param __s     [IN] The string to match.
+   * @param __re    [IN] The regular expression.
+   * @param __flags [IN] Controls how the regular expression is matched.
+   *
+   * @retval true  A match exists.
+   * @retval false Otherwise.
+   *
+   * @throws an exception of type regex_error.
+   */
+  template<typename _Ch_traits, typename _Str_allocator,
+	   typename _Ch_type, typename _Rx_traits>
+    inline bool
+    regex_match(const basic_string<_Ch_type, _Ch_traits, _Str_allocator>& __s,
+		const basic_regex<_Ch_type, _Rx_traits>& __re,
+		regex_constants::match_flag_type __flags
+		= regex_constants::match_default)
+    { return regex_match(__s.begin(), __s.end(), __re, __flags); }
+
+  // [7.11.3] Function template regex_search
+  /**
+   * Searches for a regular expression within a range.
+   * @param __s     [IN]  The start of the string to search.
+   * @param __e     [IN]  One-past-the-end of the string to search.
+   * @param __m     [OUT] The match results.
+   * @param __re    [IN]  The regular expression to search for.
+   * @param __flags [IN]  Search policy flags.
+   * @retval true  A match was found within the string.
+   * @retval false No match was found within the string, the content of %m is
+   *               undefined.
+   *
+   * @throws an exception of type regex_error.
+   */
+  template<typename _Bi_iter, typename _Alloc,
+	   typename _Ch_type, typename _Rx_traits>
+    inline bool
+    regex_search(_Bi_iter __s, _Bi_iter __e,
+		 match_results<_Bi_iter, _Alloc>& __m,
+		 const basic_regex<_Ch_type, _Rx_traits>& __re,
+		 regex_constants::match_flag_type __flags
+		 = regex_constants::match_default)
+    {
+      return __detail::__regex_algo_impl(__s, __e, __m, __re, __flags,
+	__detail::_RegexExecutorPolicy::_S_auto, false);
+    }
+
+  /**
+   * Searches for a regular expression within a range.
+   * @param __first [IN]  The start of the string to search.
+   * @param __last  [IN]  One-past-the-end of the string to search.
+   * @param __re    [IN]  The regular expression to search for.
+   * @param __flags [IN]  Search policy flags.
+   * @retval true  A match was found within the string.
+   * @retval false No match was found within the string.
+   *
+   * @throws an exception of type regex_error.
+   */
+  template<typename _Bi_iter, typename _Ch_type, typename _Rx_traits>
+    inline bool
+    regex_search(_Bi_iter __first, _Bi_iter __last,
+		 const basic_regex<_Ch_type, _Rx_traits>& __re,
+		 regex_constants::match_flag_type __flags
+		 = regex_constants::match_default)
+    {
+      match_results<_Bi_iter> __what;
+      return regex_search(__first, __last, __what, __re, __flags);
+    }
+
+  /**
+   * @brief Searches for a regular expression within a C-string.
+   * @param __s [IN]  A C-string to search for the regex.
+   * @param __m [OUT] The set of regex matches.
+   * @param __e [IN]  The regex to search for in @p s.
+   * @param __f [IN]  The search flags.
+   * @retval true  A match was found within the string.
+   * @retval false No match was found within the string, the content of %m is
+   *               undefined.
+   *
+   * @throws an exception of type regex_error.
+   */
+  template<typename _Ch_type, class _Alloc, class _Rx_traits>
+    inline bool
+    regex_search(const _Ch_type* __s,
+		 match_results<const _Ch_type*, _Alloc>& __m,
+		 const basic_regex<_Ch_type, _Rx_traits>& __e,
+		 regex_constants::match_flag_type __f
+		 = regex_constants::match_default)
+    { return regex_search(__s, __s + _Rx_traits::length(__s), __m, __e, __f); }
+
+  /**
+   * @brief Searches for a regular expression within a C-string.
+   * @param __s [IN]  The C-string to search.
+   * @param __e [IN]  The regular expression to search for.
+   * @param __f [IN]  Search policy flags.
+   * @retval true  A match was found within the string.
+   * @retval false No match was found within the string.
+   *
+   * @throws an exception of type regex_error.
+   */
+  template<typename _Ch_type, typename _Rx_traits>
+    inline bool
+    regex_search(const _Ch_type* __s,
+		 const basic_regex<_Ch_type, _Rx_traits>& __e,
+		 regex_constants::match_flag_type __f
+		 = regex_constants::match_default)
+    { return regex_search(__s, __s + _Rx_traits::length(__s), __e, __f); }
+
+  /**
+   * @brief Searches for a regular expression within a string.
+   * @param __s     [IN]  The string to search.
+   * @param __e     [IN]  The regular expression to search for.
+   * @param __flags [IN]  Search policy flags.
+   * @retval true  A match was found within the string.
+   * @retval false No match was found within the string.
+   *
+   * @throws an exception of type regex_error.
+   */
+  template<typename _Ch_traits, typename _String_allocator,
+	   typename _Ch_type, typename _Rx_traits>
+    inline bool
+    regex_search(const basic_string<_Ch_type, _Ch_traits,
+		 _String_allocator>& __s,
+		 const basic_regex<_Ch_type, _Rx_traits>& __e,
+		 regex_constants::match_flag_type __flags
+		 = regex_constants::match_default)
+    { return regex_search(__s.begin(), __s.end(), __e, __flags); }
+
+  /**
+   * @brief Searches for a regular expression within a string.
+   * @param __s [IN]  A C++ string to search for the regex.
+   * @param __m [OUT] The set of regex matches.
+   * @param __e [IN]  The regex to search for in @p s.
+   * @param __f [IN]  The search flags.
+   * @retval true  A match was found within the string.
+   * @retval false No match was found within the string, the content of %m is
+   *               undefined.
+   *
+   * @throws an exception of type regex_error.
+   */
+  template<typename _Ch_traits, typename _Ch_alloc,
+	   typename _Alloc, typename _Ch_type,
+	   typename _Rx_traits>
+    inline bool
+    regex_search(const basic_string<_Ch_type, _Ch_traits, _Ch_alloc>& __s,
+		 match_results<typename basic_string<_Ch_type,
+		 _Ch_traits, _Ch_alloc>::const_iterator, _Alloc>& __m,
+		 const basic_regex<_Ch_type, _Rx_traits>& __e,
+		 regex_constants::match_flag_type __f
+		 = regex_constants::match_default)
+    { return regex_search(__s.begin(), __s.end(), __m, __e, __f); }
+
+  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+  // 2329. regex_search() with match_results should forbid temporary strings
+  /// Prevent unsafe attempts to get match_results from a temporary string.
+  template<typename _Ch_traits, typename _Ch_alloc,
+	   typename _Alloc, typename _Ch_type,
+	   typename _Rx_traits>
+    bool
+    regex_search(const basic_string<_Ch_type, _Ch_traits, _Ch_alloc>&&,
+		 match_results<typename basic_string<_Ch_type,
+		 _Ch_traits, _Ch_alloc>::const_iterator, _Alloc>&,
+		 const basic_regex<_Ch_type, _Rx_traits>&,
+		 regex_constants::match_flag_type
+		 = regex_constants::match_default) = delete;
+
+  // std [28.11.4] Function template regex_replace
+
+  template<typename _Out_iter, typename _Bi_iter,
+	   typename _Rx_traits, typename _Ch_type>
+    _Out_iter
+    __regex_replace(_Out_iter __out, _Bi_iter __first, _Bi_iter __last,
+		    const basic_regex<_Ch_type, _Rx_traits>& __e,
+		    const _Ch_type* __fmt, size_t __len,
+		    regex_constants::match_flag_type __flags);
+
+  /**
+   * @brief Search for a regular expression within a range for multiple times,
+   and replace the matched parts through filling a format string.
+   * @param __out   [OUT] The output iterator.
+   * @param __first [IN]  The start of the string to search.
+   * @param __last  [IN]  One-past-the-end of the string to search.
+   * @param __e     [IN]  The regular expression to search for.
+   * @param __fmt   [IN]  The format string.
+   * @param __flags [IN]  Search and replace policy flags.
+   *
+   * @returns __out
+   * @throws an exception of type regex_error.
+   */
+  template<typename _Out_iter, typename _Bi_iter,
+	   typename _Rx_traits, typename _Ch_type,
+	   typename _St, typename _Sa>
+    inline _Out_iter
+    regex_replace(_Out_iter __out, _Bi_iter __first, _Bi_iter __last,
+		  const basic_regex<_Ch_type, _Rx_traits>& __e,
+		  const basic_string<_Ch_type, _St, _Sa>& __fmt,
+		  regex_constants::match_flag_type __flags
+		  = regex_constants::match_default)
+    {
+      return std::__regex_replace(__out, __first, __last, __e, __fmt.c_str(),
+				  __fmt.length(), __flags);
+    }
+
+  /**
+   * @brief Search for a regular expression within a range for multiple times,
+   and replace the matched parts through filling a format C-string.
+   * @param __out   [OUT] The output iterator.
+   * @param __first [IN]  The start of the string to search.
+   * @param __last  [IN]  One-past-the-end of the string to search.
+   * @param __e     [IN]  The regular expression to search for.
+   * @param __fmt   [IN]  The format C-string.
+   * @param __flags [IN]  Search and replace policy flags.
+   *
+   * @returns __out
+   * @throws an exception of type regex_error.
+   */
+  template<typename _Out_iter, typename _Bi_iter,
+	   typename _Rx_traits, typename _Ch_type>
+    _Out_iter
+    regex_replace(_Out_iter __out, _Bi_iter __first, _Bi_iter __last,
+		  const basic_regex<_Ch_type, _Rx_traits>& __e,
+		  const _Ch_type* __fmt,
+		  regex_constants::match_flag_type __flags
+		  = regex_constants::match_default)
+    {
+      return std::__regex_replace(__out, __first, __last, __e, __fmt,
+				  char_traits<_Ch_type>::length(__fmt),
+				  __flags);
+    }
+
+
+  /**
+   * @brief Search for a regular expression within a string for multiple times,
+   and replace the matched parts through filling a format string.
+   * @param __s     [IN] The string to search and replace.
+   * @param __e     [IN] The regular expression to search for.
+   * @param __fmt   [IN] The format string.
+   * @param __flags [IN] Search and replace policy flags.
+   *
+   * @returns The string after replacing.
+   * @throws an exception of type regex_error.
+   */
+  template<typename _Rx_traits, typename _Ch_type,
+	   typename _St, typename _Sa, typename _Fst, typename _Fsa>
+    inline basic_string<_Ch_type, _St, _Sa>
+    regex_replace(const basic_string<_Ch_type, _St, _Sa>& __s,
+		  const basic_regex<_Ch_type, _Rx_traits>& __e,
+		  const basic_string<_Ch_type, _Fst, _Fsa>& __fmt,
+		  regex_constants::match_flag_type __flags
+		  = regex_constants::match_default)
+    {
+      basic_string<_Ch_type, _St, _Sa> __result;
+      regex_replace(std::back_inserter(__result),
+		    __s.begin(), __s.end(), __e, __fmt, __flags);
+      return __result;
+    }
+
+  /**
+   * @brief Search for a regular expression within a string for multiple times,
+   and replace the matched parts through filling a format C-string.
+   * @param __s     [IN] The string to search and replace.
+   * @param __e     [IN] The regular expression to search for.
+   * @param __fmt   [IN] The format C-string.
+   * @param __flags [IN] Search and replace policy flags.
+   *
+   * @returns The string after replacing.
+   * @throws an exception of type regex_error.
+   */
+  template<typename _Rx_traits, typename _Ch_type,
+	   typename _St, typename _Sa>
+    inline basic_string<_Ch_type, _St, _Sa>
+    regex_replace(const basic_string<_Ch_type, _St, _Sa>& __s,
+		  const basic_regex<_Ch_type, _Rx_traits>& __e,
+		  const _Ch_type* __fmt,
+		  regex_constants::match_flag_type __flags
+		  = regex_constants::match_default)
+    {
+      basic_string<_Ch_type, _St, _Sa> __result;
+      regex_replace(std::back_inserter(__result),
+		    __s.begin(), __s.end(), __e, __fmt, __flags);
+      return __result;
+    }
+
+  /**
+   * @brief Search for a regular expression within a C-string for multiple
+   times, and replace the matched parts through filling a format string.
+   * @param __s     [IN] The C-string to search and replace.
+   * @param __e     [IN] The regular expression to search for.
+   * @param __fmt   [IN] The format string.
+   * @param __flags [IN] Search and replace policy flags.
+   *
+   * @returns The string after replacing.
+   * @throws an exception of type regex_error.
+   */
+  template<typename _Rx_traits, typename _Ch_type,
+	   typename _St, typename _Sa>
+    inline basic_string<_Ch_type>
+    regex_replace(const _Ch_type* __s,
+		  const basic_regex<_Ch_type, _Rx_traits>& __e,
+		  const basic_string<_Ch_type, _St, _Sa>& __fmt,
+		  regex_constants::match_flag_type __flags
+		  = regex_constants::match_default)
+    {
+      basic_string<_Ch_type> __result;
+      regex_replace(std::back_inserter(__result), __s,
+		    __s + char_traits<_Ch_type>::length(__s),
+		    __e, __fmt, __flags);
+      return __result;
+    }
+
+  /**
+   * @brief Search for a regular expression within a C-string for multiple
+   times, and replace the matched parts through filling a format C-string.
+   * @param __s     [IN] The C-string to search and replace.
+   * @param __e     [IN] The regular expression to search for.
+   * @param __fmt   [IN] The format C-string.
+   * @param __flags [IN] Search and replace policy flags.
+   *
+   * @returns The string after replacing.
+   * @throws an exception of type regex_error.
+   */
+  template<typename _Rx_traits, typename _Ch_type>
+    inline basic_string<_Ch_type>
+    regex_replace(const _Ch_type* __s,
+		  const basic_regex<_Ch_type, _Rx_traits>& __e,
+		  const _Ch_type* __fmt,
+		  regex_constants::match_flag_type __flags
+		  = regex_constants::match_default)
+    {
+      basic_string<_Ch_type> __result;
+      regex_replace(std::back_inserter(__result), __s,
+		    __s + char_traits<_Ch_type>::length(__s),
+		    __e, __fmt, __flags);
+      return __result;
+    }
+
+  ///@}
+
+_GLIBCXX_BEGIN_NAMESPACE_CXX11
+
+  // std [28.12] Class template regex_iterator
+  /**
+   * An iterator adaptor that will provide repeated calls of regex_search over
+   * a range until no more matches remain.
+   */
+  template<typename _Bi_iter,
+	   typename _Ch_type = typename iterator_traits<_Bi_iter>::value_type,
+	   typename _Rx_traits = regex_traits<_Ch_type> >
+    class regex_iterator
+    {
+    public:
+      typedef basic_regex<_Ch_type, _Rx_traits>  regex_type;
+      typedef match_results<_Bi_iter>	    value_type;
+      typedef std::ptrdiff_t		     difference_type;
+      typedef const value_type*		  pointer;
+      typedef const value_type&		  reference;
+      typedef std::forward_iterator_tag	  iterator_category;
+
+      /**
+       * @brief Provides a singular iterator, useful for indicating
+       * one-past-the-end of a range.
+       */
+      regex_iterator() = default;
+
+      /**
+       * Constructs a %regex_iterator...
+       * @param __a  [IN] The start of a text range to search.
+       * @param __b  [IN] One-past-the-end of the text range to search.
+       * @param __re [IN] The regular expression to match.
+       * @param __m  [IN] Policy flags for match rules.
+       */
+      regex_iterator(_Bi_iter __a, _Bi_iter __b, const regex_type& __re,
+		     regex_constants::match_flag_type __m
+		     = regex_constants::match_default)
+      : _M_begin(__a), _M_end(__b), _M_pregex(&__re), _M_flags(__m), _M_match()
+      {
+	if (!regex_search(_M_begin, _M_end, _M_match, *_M_pregex, _M_flags))
+	  *this = regex_iterator();
+      }
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 2332. regex_iterator should forbid temporary regexes
+      regex_iterator(_Bi_iter, _Bi_iter, const regex_type&&,
+		     regex_constants::match_flag_type
+		     = regex_constants::match_default) = delete;
+
+      /// Copy constructs a %regex_iterator.
+      regex_iterator(const regex_iterator&) = default;
+
+      /// Copy assigns one %regex_iterator to another.
+      regex_iterator&
+      operator=(const regex_iterator&) = default;
+
+      ~regex_iterator() = default;
+
+      /**
+       * @brief Tests the equivalence of two regex iterators.
+       */
+      bool
+      operator==(const regex_iterator&) const noexcept;
+
+      /**
+       * @brief Tests the inequivalence of two regex iterators.
+       */
+      bool
+      operator!=(const regex_iterator& __rhs) const noexcept
+      { return !(*this == __rhs); }
+
+      /**
+       * @brief Dereferences a %regex_iterator.
+       */
+      const value_type&
+      operator*() const noexcept
+      { return _M_match; }
+
+      /**
+       * @brief Selects a %regex_iterator member.
+       */
+      const value_type*
+      operator->() const noexcept
+      { return &_M_match; }
+
+      /**
+       * @brief Increments a %regex_iterator.
+       */
+      regex_iterator&
+      operator++();
+
+      /**
+       * @brief Postincrements a %regex_iterator.
+       */
+      regex_iterator
+      operator++(int)
+      {
+	auto __tmp = *this;
+	++(*this);
+	return __tmp;
+      }
+
+    private:
+      _Bi_iter				_M_begin {};
+      _Bi_iter				_M_end {};
+      const regex_type*			_M_pregex = nullptr;
+      regex_constants::match_flag_type	_M_flags {};
+      match_results<_Bi_iter>		_M_match;
+    };
+
+  typedef regex_iterator<const char*>			cregex_iterator;
+  typedef regex_iterator<string::const_iterator>	sregex_iterator;
+#ifdef _GLIBCXX_USE_WCHAR_T
+  typedef regex_iterator<const wchar_t*>		wcregex_iterator;
+  typedef regex_iterator<wstring::const_iterator>	wsregex_iterator;
+#endif
+
+  // [7.12.2] Class template regex_token_iterator
+  /**
+   * Iterates over submatches in a range (or @a splits a text string).
+   *
+   * The purpose of this iterator is to enumerate all, or all specified,
+   * matches of a regular expression within a text range.  The dereferenced
+   * value of an iterator of this class is a std::sub_match object.
+   */
+  template<typename _Bi_iter,
+	   typename _Ch_type = typename iterator_traits<_Bi_iter>::value_type,
+	   typename _Rx_traits = regex_traits<_Ch_type> >
+    class regex_token_iterator
+    {
+    public:
+      typedef basic_regex<_Ch_type, _Rx_traits>	regex_type;
+      typedef sub_match<_Bi_iter>		value_type;
+      typedef std::ptrdiff_t			difference_type;
+      typedef const value_type*			pointer;
+      typedef const value_type&			reference;
+      typedef std::forward_iterator_tag		iterator_category;
+
+    public:
+      /**
+       * @brief Default constructs a %regex_token_iterator.
+       *
+       * A default-constructed %regex_token_iterator is a singular iterator
+       * that will compare equal to the one-past-the-end value for any
+       * iterator of the same type.
+       */
+      regex_token_iterator()
+      : _M_position(), _M_subs(), _M_suffix(), _M_n(0), _M_result(nullptr),
+      _M_has_m1(false)
+      { }
+
+      /**
+       * Constructs a %regex_token_iterator...
+       * @param __a          [IN] The start of the text to search.
+       * @param __b          [IN] One-past-the-end of the text to search.
+       * @param __re         [IN] The regular expression to search for.
+       * @param __submatch   [IN] Which submatch to return.  There are some
+       *                        special values for this parameter:
+       *                        - -1 each enumerated subexpression does NOT
+       *                          match the regular expression (aka field
+       *                          splitting)
+       *                        - 0 the entire string matching the
+       *                          subexpression is returned for each match
+       *                          within the text.
+       *                        - >0 enumerates only the indicated
+       *                          subexpression from a match within the text.
+       * @param __m          [IN] Policy flags for match rules.
+       */
+      regex_token_iterator(_Bi_iter __a, _Bi_iter __b, const regex_type& __re,
+			   int __submatch = 0,
+			   regex_constants::match_flag_type __m
+			   = regex_constants::match_default)
+      : _M_position(__a, __b, __re, __m), _M_subs(1, __submatch), _M_n(0)
+      { _M_init(__a, __b); }
+
+      /**
+       * Constructs a %regex_token_iterator...
+       * @param __a          [IN] The start of the text to search.
+       * @param __b          [IN] One-past-the-end of the text to search.
+       * @param __re         [IN] The regular expression to search for.
+       * @param __submatches [IN] A list of subexpressions to return for each
+       *                          regular expression match within the text.
+       * @param __m          [IN] Policy flags for match rules.
+       */
+      regex_token_iterator(_Bi_iter __a, _Bi_iter __b,
+			   const regex_type& __re,
+			   const std::vector<int>& __submatches,
+			   regex_constants::match_flag_type __m
+			     = regex_constants::match_default)
+      : _M_position(__a, __b, __re, __m), _M_subs(__submatches), _M_n(0)
+      { _M_init(__a, __b); }
+
+      /**
+       * Constructs a %regex_token_iterator...
+       * @param __a          [IN] The start of the text to search.
+       * @param __b          [IN] One-past-the-end of the text to search.
+       * @param __re         [IN] The regular expression to search for.
+       * @param __submatches [IN] A list of subexpressions to return for each
+       *                          regular expression match within the text.
+       * @param __m          [IN] Policy flags for match rules.
+       */
+      regex_token_iterator(_Bi_iter __a, _Bi_iter __b,
+			   const regex_type& __re,
+			   initializer_list<int> __submatches,
+			   regex_constants::match_flag_type __m
+			     = regex_constants::match_default)
+      : _M_position(__a, __b, __re, __m), _M_subs(__submatches), _M_n(0)
+      { _M_init(__a, __b); }
+
+      /**
+       * Constructs a %regex_token_iterator...
+       * @param __a          [IN] The start of the text to search.
+       * @param __b          [IN] One-past-the-end of the text to search.
+       * @param __re         [IN] The regular expression to search for.
+       * @param __submatches [IN] A list of subexpressions to return for each
+       *                          regular expression match within the text.
+       * @param __m          [IN] Policy flags for match rules.
+       */
+      template<std::size_t _Nm>
+	regex_token_iterator(_Bi_iter __a, _Bi_iter __b,
+			     const regex_type& __re,
+			     const int (&__submatches)[_Nm],
+			     regex_constants::match_flag_type __m
+			     = regex_constants::match_default)
+      : _M_position(__a, __b, __re, __m),
+      _M_subs(__submatches, __submatches + _Nm), _M_n(0)
+      { _M_init(__a, __b); }
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 2332. regex_token_iterator should forbid temporary regexes
+      regex_token_iterator(_Bi_iter, _Bi_iter, const regex_type&&, int = 0,
+			   regex_constants::match_flag_type =
+			   regex_constants::match_default) = delete;
+      regex_token_iterator(_Bi_iter, _Bi_iter, const regex_type&&,
+			   const std::vector<int>&,
+			   regex_constants::match_flag_type =
+			   regex_constants::match_default) = delete;
+      regex_token_iterator(_Bi_iter, _Bi_iter, const regex_type&&,
+			   initializer_list<int>,
+			   regex_constants::match_flag_type =
+			   regex_constants::match_default) = delete;
+      template <std::size_t _Nm>
+	regex_token_iterator(_Bi_iter, _Bi_iter, const regex_type&&,
+			     const int (&)[_Nm],
+			     regex_constants::match_flag_type =
+			     regex_constants::match_default) = delete;
+
+      /**
+       * @brief Copy constructs a %regex_token_iterator.
+       * @param __rhs [IN] A %regex_token_iterator to copy.
+       */
+      regex_token_iterator(const regex_token_iterator& __rhs)
+      : _M_position(__rhs._M_position), _M_subs(__rhs._M_subs),
+      _M_suffix(__rhs._M_suffix), _M_n(__rhs._M_n), _M_has_m1(__rhs._M_has_m1)
+      { _M_normalize_result(); }
+
+      /**
+       * @brief Assigns a %regex_token_iterator to another.
+       * @param __rhs [IN] A %regex_token_iterator to copy.
+       */
+      regex_token_iterator&
+      operator=(const regex_token_iterator& __rhs);
+
+      /**
+       * @brief Compares a %regex_token_iterator to another for equality.
+       */
+      bool
+      operator==(const regex_token_iterator& __rhs) const;
+
+      /**
+       * @brief Compares a %regex_token_iterator to another for inequality.
+       */
+      bool
+      operator!=(const regex_token_iterator& __rhs) const
+      { return !(*this == __rhs); }
+
+      /**
+       * @brief Dereferences a %regex_token_iterator.
+       */
+      const value_type&
+      operator*() const
+      { return *_M_result; }
+
+      /**
+       * @brief Selects a %regex_token_iterator member.
+       */
+      const value_type*
+      operator->() const
+      { return _M_result; }
+
+      /**
+       * @brief Increments a %regex_token_iterator.
+       */
+      regex_token_iterator&
+      operator++();
+
+      /**
+       * @brief Postincrements a %regex_token_iterator.
+       */
+      regex_token_iterator
+      operator++(int)
+      {
+	auto __tmp = *this;
+	++(*this);
+	return __tmp;
+      }
+
+    private:
+      typedef regex_iterator<_Bi_iter, _Ch_type, _Rx_traits> _Position;
+
+      void
+      _M_init(_Bi_iter __a, _Bi_iter __b);
+
+      const value_type&
+      _M_current_match() const
+      {
+	if (_M_subs[_M_n] == -1)
+	  return (*_M_position).prefix();
+	else
+	  return (*_M_position)[_M_subs[_M_n]];
+      }
+
+      constexpr bool
+      _M_end_of_seq() const
+      { return _M_result == nullptr; }
+
+      // [28.12.2.2.4]
+      void
+      _M_normalize_result()
+      {
+	if (_M_position != _Position())
+	  _M_result = &_M_current_match();
+	else if (_M_has_m1)
+	  _M_result = &_M_suffix;
+	else
+	  _M_result = nullptr;
+      }
+
+      _Position		_M_position;
+      std::vector<int>	_M_subs;
+      value_type	_M_suffix;
+      std::size_t	_M_n;
+      const value_type*	_M_result;
+
+      // Show whether _M_subs contains -1
+      bool		_M_has_m1;
+    };
+
+  /** @brief Token iterator for C-style NULL-terminated strings. */
+  typedef regex_token_iterator<const char*>		cregex_token_iterator;
+
+  /** @brief Token iterator for standard strings. */
+  typedef regex_token_iterator<string::const_iterator>	sregex_token_iterator;
+
+#ifdef _GLIBCXX_USE_WCHAR_T
+  /** @brief Token iterator for C-style NULL-terminated wide strings. */
+  typedef regex_token_iterator<const wchar_t*>		wcregex_token_iterator;
+
+  /** @brief Token iterator for standard wide-character strings. */
+  typedef regex_token_iterator<wstring::const_iterator> wsregex_token_iterator;
+#endif
+
+  ///@} // group regex
+
+_GLIBCXX_END_NAMESPACE_CXX11
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#include <bits/regex.tcc>
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@regex.tcc b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@regex.tcc
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@regex.tcc
@@ -0,0 +1,671 @@
+// class template regex -*- C++ -*-
+
+// Copyright (C) 2013-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/**
+ *  @file bits/regex.tcc
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{regex}
+ */
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+namespace __detail
+{
+  /// @cond undocumented
+
+  // Result of merging regex_match and regex_search.
+  //
+  // __policy now can be _S_auto (auto dispatch) and _S_alternate (use
+  // the other one if possible, for test purpose).
+  //
+  // That __match_mode is true means regex_match, else regex_search.
+  template<typename _BiIter, typename _Alloc,
+	   typename _CharT, typename _TraitsT>
+    bool
+    __regex_algo_impl(_BiIter                              __s,
+		      _BiIter                              __e,
+		      match_results<_BiIter, _Alloc>&      __m,
+		      const basic_regex<_CharT, _TraitsT>& __re,
+		      regex_constants::match_flag_type     __flags,
+		      _RegexExecutorPolicy		   __policy,
+		      bool				   __match_mode)
+    {
+      if (__re._M_automaton == nullptr)
+	return false;
+
+      typename match_results<_BiIter, _Alloc>::_Unchecked& __res = __m;
+      __m._M_begin = __s;
+      __m._M_resize(__re._M_automaton->_M_sub_count());
+
+      bool __ret;
+      if ((__re.flags() & regex_constants::__polynomial)
+	  || (__policy == _RegexExecutorPolicy::_S_alternate
+	      && !__re._M_automaton->_M_has_backref))
+	{
+	  _Executor<_BiIter, _Alloc, _TraitsT, false>
+	    __executor(__s, __e, __res, __re, __flags);
+	  if (__match_mode)
+	    __ret = __executor._M_match();
+	  else
+	    __ret = __executor._M_search();
+	}
+      else
+	{
+	  _Executor<_BiIter, _Alloc, _TraitsT, true>
+	    __executor(__s, __e, __res, __re, __flags);
+	  if (__match_mode)
+	    __ret = __executor._M_match();
+	  else
+	    __ret = __executor._M_search();
+	}
+      if (__ret)
+	{
+	  for (auto& __it : __res)
+	    if (!__it.matched)
+	      __it.first = __it.second = __e;
+	  auto& __pre = __m._M_prefix();
+	  auto& __suf = __m._M_suffix();
+	  if (__match_mode)
+	    {
+	      __pre.matched = false;
+	      __pre.first = __s;
+	      __pre.second = __s;
+	      __suf.matched = false;
+	      __suf.first = __e;
+	      __suf.second = __e;
+	    }
+	  else
+	    {
+	      __pre.first = __s;
+	      __pre.second = __res[0].first;
+	      __pre.matched = (__pre.first != __pre.second);
+	      __suf.first = __res[0].second;
+	      __suf.second = __e;
+	      __suf.matched = (__suf.first != __suf.second);
+	    }
+	}
+      else
+	{
+	  __m._M_establish_failed_match(__e);
+	}
+      return __ret;
+    }
+  /// @endcond
+} // namespace __detail
+
+  /// @cond
+
+  template<typename _Ch_type>
+  template<typename _Fwd_iter>
+    typename regex_traits<_Ch_type>::string_type
+    regex_traits<_Ch_type>::
+    lookup_collatename(_Fwd_iter __first, _Fwd_iter __last) const
+    {
+      typedef std::ctype<char_type> __ctype_type;
+      const __ctype_type& __fctyp(use_facet<__ctype_type>(_M_locale));
+
+      static const char* __collatenames[] =
+	{
+	  "NUL",
+	  "SOH",
+	  "STX",
+	  "ETX",
+	  "EOT",
+	  "ENQ",
+	  "ACK",
+	  "alert",
+	  "backspace",
+	  "tab",
+	  "newline",
+	  "vertical-tab",
+	  "form-feed",
+	  "carriage-return",
+	  "SO",
+	  "SI",
+	  "DLE",
+	  "DC1",
+	  "DC2",
+	  "DC3",
+	  "DC4",
+	  "NAK",
+	  "SYN",
+	  "ETB",
+	  "CAN",
+	  "EM",
+	  "SUB",
+	  "ESC",
+	  "IS4",
+	  "IS3",
+	  "IS2",
+	  "IS1",
+	  "space",
+	  "exclamation-mark",
+	  "quotation-mark",
+	  "number-sign",
+	  "dollar-sign",
+	  "percent-sign",
+	  "ampersand",
+	  "apostrophe",
+	  "left-parenthesis",
+	  "right-parenthesis",
+	  "asterisk",
+	  "plus-sign",
+	  "comma",
+	  "hyphen",
+	  "period",
+	  "slash",
+	  "zero",
+	  "one",
+	  "two",
+	  "three",
+	  "four",
+	  "five",
+	  "six",
+	  "seven",
+	  "eight",
+	  "nine",
+	  "colon",
+	  "semicolon",
+	  "less-than-sign",
+	  "equals-sign",
+	  "greater-than-sign",
+	  "question-mark",
+	  "commercial-at",
+	  "A",
+	  "B",
+	  "C",
+	  "D",
+	  "E",
+	  "F",
+	  "G",
+	  "H",
+	  "I",
+	  "J",
+	  "K",
+	  "L",
+	  "M",
+	  "N",
+	  "O",
+	  "P",
+	  "Q",
+	  "R",
+	  "S",
+	  "T",
+	  "U",
+	  "V",
+	  "W",
+	  "X",
+	  "Y",
+	  "Z",
+	  "left-square-bracket",
+	  "backslash",
+	  "right-square-bracket",
+	  "circumflex",
+	  "underscore",
+	  "grave-accent",
+	  "a",
+	  "b",
+	  "c",
+	  "d",
+	  "e",
+	  "f",
+	  "g",
+	  "h",
+	  "i",
+	  "j",
+	  "k",
+	  "l",
+	  "m",
+	  "n",
+	  "o",
+	  "p",
+	  "q",
+	  "r",
+	  "s",
+	  "t",
+	  "u",
+	  "v",
+	  "w",
+	  "x",
+	  "y",
+	  "z",
+	  "left-curly-bracket",
+	  "vertical-line",
+	  "right-curly-bracket",
+	  "tilde",
+	  "DEL",
+	};
+
+      string __s;
+      for (; __first != __last; ++__first)
+	__s += __fctyp.narrow(*__first, 0);
+
+      for (const auto& __it : __collatenames)
+	if (__s == __it)
+	  return string_type(1, __fctyp.widen(
+	    static_cast<char>(&__it - __collatenames)));
+
+      // TODO Add digraph support:
+      // http://boost.sourceforge.net/libs/regex/doc/collating_names.html
+
+      return string_type();
+    }
+
+  template<typename _Ch_type>
+  template<typename _Fwd_iter>
+    typename regex_traits<_Ch_type>::char_class_type
+    regex_traits<_Ch_type>::
+    lookup_classname(_Fwd_iter __first, _Fwd_iter __last, bool __icase) const
+    {
+      typedef std::ctype<char_type> __ctype_type;
+      const __ctype_type& __fctyp(use_facet<__ctype_type>(_M_locale));
+
+      // Mappings from class name to class mask.
+      static const pair<const char*, char_class_type> __classnames[] =
+      {
+	{"d", ctype_base::digit},
+	{"w", {ctype_base::alnum, _RegexMask::_S_under}},
+	{"s", ctype_base::space},
+	{"alnum", ctype_base::alnum},
+	{"alpha", ctype_base::alpha},
+	{"blank", ctype_base::blank},
+	{"cntrl", ctype_base::cntrl},
+	{"digit", ctype_base::digit},
+	{"graph", ctype_base::graph},
+	{"lower", ctype_base::lower},
+	{"print", ctype_base::print},
+	{"punct", ctype_base::punct},
+	{"space", ctype_base::space},
+	{"upper", ctype_base::upper},
+	{"xdigit", ctype_base::xdigit},
+      };
+
+      string __s;
+      for (; __first != __last; ++__first)
+	__s += __fctyp.narrow(__fctyp.tolower(*__first), 0);
+
+      for (const auto& __it : __classnames)
+	if (__s == __it.first)
+	  {
+	    if (__icase
+		&& ((__it.second
+		     & (ctype_base::lower | ctype_base::upper)) != 0))
+	      return ctype_base::alpha;
+	    return __it.second;
+	  }
+      return 0;
+    }
+
+  template<typename _Ch_type>
+    bool
+    regex_traits<_Ch_type>::
+    isctype(_Ch_type __c, char_class_type __f) const
+    {
+      typedef std::ctype<char_type> __ctype_type;
+      const __ctype_type& __fctyp(use_facet<__ctype_type>(_M_locale));
+
+      return __fctyp.is(__f._M_base, __c)
+	// [[:w:]]
+	|| ((__f._M_extended & _RegexMask::_S_under)
+	    && __c == __fctyp.widen('_'));
+    }
+
+  template<typename _Ch_type>
+    int
+    regex_traits<_Ch_type>::
+    value(_Ch_type __ch, int __radix) const
+    {
+      std::basic_istringstream<char_type> __is(string_type(1, __ch));
+      long __v;
+      if (__radix == 8)
+	__is >> std::oct;
+      else if (__radix == 16)
+	__is >> std::hex;
+      __is >> __v;
+      return __is.fail() ? -1 : __v;
+    }
+
+  template<typename _Bi_iter, typename _Alloc>
+  template<typename _Out_iter>
+    _Out_iter
+    match_results<_Bi_iter, _Alloc>::
+    format(_Out_iter __out,
+	   const match_results<_Bi_iter, _Alloc>::char_type* __fmt_first,
+	   const match_results<_Bi_iter, _Alloc>::char_type* __fmt_last,
+	   match_flag_type __flags) const
+    {
+      __glibcxx_assert( ready() );
+      regex_traits<char_type> __traits;
+      typedef std::ctype<char_type> __ctype_type;
+      const __ctype_type&
+	__fctyp(use_facet<__ctype_type>(__traits.getloc()));
+
+      auto __output = [&](size_t __idx)
+	{
+	  auto& __sub = (*this)[__idx];
+	  if (__sub.matched)
+	    __out = std::copy(__sub.first, __sub.second, __out);
+	};
+
+      if (__flags & regex_constants::format_sed)
+	{
+	  bool __escaping = false;
+	  for (; __fmt_first != __fmt_last; __fmt_first++)
+	    {
+	      if (__escaping)
+		{
+		  __escaping = false;
+		  if (__fctyp.is(__ctype_type::digit, *__fmt_first))
+		    __output(__traits.value(*__fmt_first, 10));
+		  else
+		    *__out++ = *__fmt_first;
+		  continue;
+		}
+	      if (*__fmt_first == '\\')
+		{
+		  __escaping = true;
+		  continue;
+		}
+	      if (*__fmt_first == '&')
+		{
+		  __output(0);
+		  continue;
+		}
+	      *__out++ = *__fmt_first;
+	    }
+	  if (__escaping)
+	    *__out++ = '\\';
+	}
+      else
+	{
+	  while (1)
+	    {
+	      auto __next = std::find(__fmt_first, __fmt_last, '$');
+	      if (__next == __fmt_last)
+		break;
+
+	      __out = std::copy(__fmt_first, __next, __out);
+
+	      auto __eat = [&](char __ch) -> bool
+		{
+		  if (*__next == __ch)
+		    {
+		      ++__next;
+		      return true;
+		    }
+		  return false;
+		};
+
+	      if (++__next == __fmt_last)
+		*__out++ = '$';
+	      else if (__eat('$'))
+		*__out++ = '$';
+	      else if (__eat('&'))
+		__output(0);
+	      else if (__eat('`'))
+		{
+		  auto& __sub = _M_prefix();
+		  if (__sub.matched)
+		    __out = std::copy(__sub.first, __sub.second, __out);
+		}
+	      else if (__eat('\''))
+		{
+		  auto& __sub = _M_suffix();
+		  if (__sub.matched)
+		    __out = std::copy(__sub.first, __sub.second, __out);
+		}
+	      else if (__fctyp.is(__ctype_type::digit, *__next))
+		{
+		  long __num = __traits.value(*__next, 10);
+		  if (++__next != __fmt_last
+		      && __fctyp.is(__ctype_type::digit, *__next))
+		    {
+		      __num *= 10;
+		      __num += __traits.value(*__next++, 10);
+		    }
+		  if (0 <= __num && __num < this->size())
+		    __output(__num);
+		}
+	      else
+		*__out++ = '$';
+	      __fmt_first = __next;
+	    }
+	  __out = std::copy(__fmt_first, __fmt_last, __out);
+	}
+      return __out;
+    }
+
+  template<typename _Out_iter, typename _Bi_iter,
+	   typename _Rx_traits, typename _Ch_type>
+    _Out_iter
+    __regex_replace(_Out_iter __out, _Bi_iter __first, _Bi_iter __last,
+		    const basic_regex<_Ch_type, _Rx_traits>& __e,
+		    const _Ch_type* __fmt, size_t __len,
+		    regex_constants::match_flag_type __flags)
+    {
+      typedef regex_iterator<_Bi_iter, _Ch_type, _Rx_traits> _IterT;
+      _IterT __i(__first, __last, __e, __flags);
+      _IterT __end;
+      if (__i == __end)
+	{
+	  if (!(__flags & regex_constants::format_no_copy))
+	    __out = std::copy(__first, __last, __out);
+	}
+      else
+	{
+	  sub_match<_Bi_iter> __last;
+	  for (; __i != __end; ++__i)
+	    {
+	      if (!(__flags & regex_constants::format_no_copy))
+		__out = std::copy(__i->prefix().first, __i->prefix().second,
+				  __out);
+	      __out = __i->format(__out, __fmt, __fmt + __len, __flags);
+	      __last = __i->suffix();
+	      if (__flags & regex_constants::format_first_only)
+		break;
+	    }
+	  if (!(__flags & regex_constants::format_no_copy))
+	    __out = std::copy(__last.first, __last.second, __out);
+	}
+      return __out;
+    }
+
+  template<typename _Bi_iter,
+	   typename _Ch_type,
+	   typename _Rx_traits>
+    bool
+    regex_iterator<_Bi_iter, _Ch_type, _Rx_traits>::
+    operator==(const regex_iterator& __rhs) const noexcept
+    {
+      if (_M_pregex == nullptr && __rhs._M_pregex == nullptr)
+	return true;
+      return _M_pregex == __rhs._M_pregex
+	  && _M_begin == __rhs._M_begin
+	  && _M_end == __rhs._M_end
+	  && _M_flags == __rhs._M_flags
+	  && _M_match[0] == __rhs._M_match[0];
+    }
+
+  template<typename _Bi_iter,
+	   typename _Ch_type,
+	   typename _Rx_traits>
+    regex_iterator<_Bi_iter, _Ch_type, _Rx_traits>&
+    regex_iterator<_Bi_iter, _Ch_type, _Rx_traits>::
+    operator++()
+    {
+      // In all cases in which the call to regex_search returns true,
+      // match.prefix().first shall be equal to the previous value of
+      // match[0].second, and for each index i in the half-open range
+      // [0, match.size()) for which match[i].matched is true,
+      // match[i].position() shall return distance(begin, match[i].first).
+      // [28.12.1.4.5]
+      if (_M_match[0].matched)
+	{
+	  auto __start = _M_match[0].second;
+	  auto __prefix_first = _M_match[0].second;
+	  if (_M_match[0].first == _M_match[0].second)
+	    {
+	      if (__start == _M_end)
+		{
+		  _M_pregex = nullptr;
+		  return *this;
+		}
+	      else
+		{
+		  if (regex_search(__start, _M_end, _M_match, *_M_pregex,
+				   _M_flags
+				   | regex_constants::match_not_null
+				   | regex_constants::match_continuous))
+		    {
+		      __glibcxx_assert(_M_match[0].matched);
+		      auto& __prefix = _M_match._M_prefix();
+		      __prefix.first = __prefix_first;
+		      __prefix.matched = __prefix.first != __prefix.second;
+		      // [28.12.1.4.5]
+		      _M_match._M_begin = _M_begin;
+		      return *this;
+		    }
+		  else
+		    ++__start;
+		}
+	    }
+	  _M_flags |= regex_constants::match_prev_avail;
+	  if (regex_search(__start, _M_end, _M_match, *_M_pregex, _M_flags))
+	    {
+	      __glibcxx_assert(_M_match[0].matched);
+	      auto& __prefix = _M_match._M_prefix();
+	      __prefix.first = __prefix_first;
+	      __prefix.matched = __prefix.first != __prefix.second;
+	      // [28.12.1.4.5]
+	      _M_match._M_begin = _M_begin;
+	    }
+	  else
+	    _M_pregex = nullptr;
+	}
+      return *this;
+    }
+
+  template<typename _Bi_iter,
+	   typename _Ch_type,
+	   typename _Rx_traits>
+    regex_token_iterator<_Bi_iter, _Ch_type, _Rx_traits>&
+    regex_token_iterator<_Bi_iter, _Ch_type, _Rx_traits>::
+    operator=(const regex_token_iterator& __rhs)
+    {
+      _M_position = __rhs._M_position;
+      _M_subs = __rhs._M_subs;
+      _M_n = __rhs._M_n;
+      _M_suffix = __rhs._M_suffix;
+      _M_has_m1 = __rhs._M_has_m1;
+      _M_normalize_result();
+      return *this;
+    }
+
+  template<typename _Bi_iter,
+	   typename _Ch_type,
+	   typename _Rx_traits>
+    bool
+    regex_token_iterator<_Bi_iter, _Ch_type, _Rx_traits>::
+    operator==(const regex_token_iterator& __rhs) const
+    {
+      if (_M_end_of_seq() && __rhs._M_end_of_seq())
+	return true;
+      if (_M_suffix.matched && __rhs._M_suffix.matched
+	  && _M_suffix == __rhs._M_suffix)
+	return true;
+      if (_M_end_of_seq() || _M_suffix.matched
+	  || __rhs._M_end_of_seq() || __rhs._M_suffix.matched)
+	return false;
+      return _M_position == __rhs._M_position
+	&& _M_n == __rhs._M_n
+	&& _M_subs == __rhs._M_subs;
+    }
+
+  template<typename _Bi_iter,
+	   typename _Ch_type,
+	   typename _Rx_traits>
+    regex_token_iterator<_Bi_iter, _Ch_type, _Rx_traits>&
+    regex_token_iterator<_Bi_iter, _Ch_type, _Rx_traits>::
+    operator++()
+    {
+      _Position __prev = _M_position;
+      if (_M_suffix.matched)
+	*this = regex_token_iterator();
+      else if (_M_n + 1 < _M_subs.size())
+	{
+	  _M_n++;
+	  _M_result = &_M_current_match();
+	}
+      else
+	{
+	  _M_n = 0;
+	  ++_M_position;
+	  if (_M_position != _Position())
+	    _M_result = &_M_current_match();
+	  else if (_M_has_m1 && __prev->suffix().length() != 0)
+	    {
+	      _M_suffix.matched = true;
+	      _M_suffix.first = __prev->suffix().first;
+	      _M_suffix.second = __prev->suffix().second;
+	      _M_result = &_M_suffix;
+	    }
+	  else
+	    *this = regex_token_iterator();
+	}
+      return *this;
+    }
+
+  template<typename _Bi_iter,
+	   typename _Ch_type,
+	   typename _Rx_traits>
+    void
+    regex_token_iterator<_Bi_iter, _Ch_type, _Rx_traits>::
+    _M_init(_Bi_iter __a, _Bi_iter __b)
+    {
+      _M_has_m1 = false;
+      for (auto __it : _M_subs)
+	if (__it == -1)
+	  {
+	    _M_has_m1 = true;
+	    break;
+	  }
+      if (_M_position != _Position())
+	_M_result = &_M_current_match();
+      else if (_M_has_m1)
+	{
+	  _M_suffix.matched = true;
+	  _M_suffix.first = __a;
+	  _M_suffix.second = __b;
+	  _M_result = &_M_suffix;
+	}
+      else
+	_M_result = nullptr;
+    }
+
+  /// @endcond
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@regex.tcc.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@regex.tcc.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@regex_automaton.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@regex_automaton.h
new file mode 100644
index 0000000000000000000000000000000000000000..f95eb7dad6d8b0a7c2c0ac056bb03c6d955ba750
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@regex_automaton.h
@@ -0,0 +1,400 @@
+// class template regex -*- C++ -*-
+
+// Copyright (C) 2013-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/**
+ *  @file bits/regex_automaton.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{regex}
+ */
+
+// This macro defines the maximal state number a NFA can have.
+#ifndef _GLIBCXX_REGEX_STATE_LIMIT
+#define _GLIBCXX_REGEX_STATE_LIMIT 100000
+#endif
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+namespace __detail
+{
+  /**
+   *  @defgroup regex-detail Base and Implementation Classes
+   *  @ingroup regex
+   *  @{
+   */
+
+  typedef long _StateIdT;
+  static const _StateIdT _S_invalid_state_id  = -1;
+
+  template<typename _CharT>
+    using _Matcher = std::function<bool (_CharT)>;
+
+  /// Operation codes that define the type of transitions within the base NFA
+  /// that represents the regular expression.
+  enum _Opcode : int
+  {
+      _S_opcode_unknown,
+      _S_opcode_alternative,
+      _S_opcode_repeat,
+      _S_opcode_backref,
+      _S_opcode_line_begin_assertion,
+      _S_opcode_line_end_assertion,
+      _S_opcode_word_boundary,
+      _S_opcode_subexpr_lookahead,
+      _S_opcode_subexpr_begin,
+      _S_opcode_subexpr_end,
+      _S_opcode_dummy,
+      _S_opcode_match,
+      _S_opcode_accept,
+  };
+
+  struct _State_base
+  {
+  protected:
+    _Opcode      _M_opcode;           // type of outgoing transition
+
+  public:
+    _StateIdT    _M_next;             // outgoing transition
+    union // Since they are mutually exclusive.
+    {
+      size_t _M_subexpr;        // for _S_opcode_subexpr_*
+      size_t _M_backref_index;  // for _S_opcode_backref
+      struct
+      {
+	// for _S_opcode_alternative, _S_opcode_repeat and
+	// _S_opcode_subexpr_lookahead
+	_StateIdT  _M_alt;
+	// for _S_opcode_word_boundary or _S_opcode_subexpr_lookahead or
+	// quantifiers (ungreedy if set true)
+	bool       _M_neg;
+      };
+      // For _S_opcode_match
+      __gnu_cxx::__aligned_membuf<_Matcher<char>> _M_matcher_storage;
+    };
+
+  protected:
+    explicit _State_base(_Opcode __opcode) noexcept
+    : _M_opcode(__opcode), _M_next(_S_invalid_state_id)
+    { }
+
+  public:
+    bool
+    _M_has_alt() const noexcept
+    {
+      return _M_opcode == _S_opcode_alternative
+	|| _M_opcode == _S_opcode_repeat
+	|| _M_opcode == _S_opcode_subexpr_lookahead;
+    }
+
+#ifdef _GLIBCXX_DEBUG
+    std::ostream&
+    _M_print(std::ostream& ostr) const;
+
+    // Prints graphviz dot commands for state.
+    std::ostream&
+    _M_dot(std::ostream& __ostr, _StateIdT __id) const;
+#endif
+  };
+
+  template<typename _Char_type>
+    struct _State : _State_base
+    {
+      typedef _Matcher<_Char_type> _MatcherT;
+      static_assert(sizeof(_MatcherT) == sizeof(_Matcher<char>),
+		    "std::function<bool(T)> has the same size as "
+		    "std::function<bool(char)>");
+      static_assert(alignof(_MatcherT) == alignof(_Matcher<char>),
+		    "std::function<bool(T)> has the same alignment as "
+		    "std::function<bool(char)>");
+
+      explicit
+      _State(_Opcode __opcode) noexcept : _State_base(__opcode)
+      {
+	if (_M_opcode() == _S_opcode_match)
+	  new (this->_M_matcher_storage._M_addr()) _MatcherT();
+      }
+
+      _State(const _State& __rhs) : _State_base(__rhs)
+      {
+	if (__rhs._M_opcode() == _S_opcode_match)
+	  new (this->_M_matcher_storage._M_addr())
+	    _MatcherT(__rhs._M_get_matcher());
+      }
+
+      _State(_State&& __rhs) noexcept : _State_base(__rhs)
+      {
+	if (__rhs._M_opcode() == _S_opcode_match)
+	  new (this->_M_matcher_storage._M_addr())
+	    _MatcherT(std::move(__rhs._M_get_matcher()));
+      }
+
+      _State&
+      operator=(const _State&) = delete;
+
+      ~_State()
+      {
+	if (_M_opcode() == _S_opcode_match)
+	  _M_get_matcher().~_MatcherT();
+      }
+
+      // Since correct ctor and dtor rely on _M_opcode, it's better not to
+      // change it over time.
+      _Opcode
+      _M_opcode() const noexcept
+      { return _State_base::_M_opcode; }
+
+      bool
+      _M_matches(_Char_type __char) const
+      { return _M_get_matcher()(__char); }
+
+      _MatcherT&
+      _M_get_matcher() noexcept
+      { return *static_cast<_MatcherT*>(this->_M_matcher_storage._M_addr()); }
+
+      const _MatcherT&
+      _M_get_matcher() const noexcept
+      {
+	return *static_cast<const _MatcherT*>(
+	    this->_M_matcher_storage._M_addr());
+      }
+    };
+
+  struct _NFA_base
+  {
+    typedef regex_constants::syntax_option_type _FlagT;
+
+    explicit
+    _NFA_base(_FlagT __f) noexcept
+    : _M_flags(__f), _M_start_state(0), _M_subexpr_count(0),
+    _M_has_backref(false)
+    { }
+
+    _NFA_base(_NFA_base&&) = default;
+
+  protected:
+    ~_NFA_base() = default;
+
+  public:
+    _FlagT
+    _M_options() const noexcept
+    { return _M_flags; }
+
+    _StateIdT
+    _M_start() const noexcept
+    { return _M_start_state; }
+
+    size_t
+    _M_sub_count() const noexcept
+    { return _M_subexpr_count; }
+
+    _GLIBCXX_STD_C::vector<size_t> _M_paren_stack;
+    _FlagT                    _M_flags;
+    _StateIdT                 _M_start_state;
+    size_t                    _M_subexpr_count;
+    bool                      _M_has_backref;
+  };
+
+  template<typename _TraitsT>
+    struct _NFA
+    : _NFA_base, _GLIBCXX_STD_C::vector<_State<typename _TraitsT::char_type>>
+    {
+      typedef typename _TraitsT::char_type	_Char_type;
+      typedef _State<_Char_type>		_StateT;
+      typedef _Matcher<_Char_type>		_MatcherT;
+
+      _NFA(const typename _TraitsT::locale_type& __loc, _FlagT __flags)
+      : _NFA_base(__flags)
+      { _M_traits.imbue(__loc); }
+
+      // for performance reasons _NFA objects should only be moved not copied
+      _NFA(const _NFA&) = delete;
+      _NFA(_NFA&&) = default;
+
+      _StateIdT
+      _M_insert_accept()
+      {
+	auto __ret = _M_insert_state(_StateT(_S_opcode_accept));
+	return __ret;
+      }
+
+      _StateIdT
+      _M_insert_alt(_StateIdT __next, _StateIdT __alt,
+		    bool __neg __attribute__((__unused__)))
+      {
+	_StateT __tmp(_S_opcode_alternative);
+	// It labels every quantifier to make greedy comparison easier in BFS
+	// approach.
+	__tmp._M_next = __next;
+	__tmp._M_alt = __alt;
+	return _M_insert_state(std::move(__tmp));
+      }
+
+      _StateIdT
+      _M_insert_repeat(_StateIdT __next, _StateIdT __alt, bool __neg)
+      {
+	_StateT __tmp(_S_opcode_repeat);
+	// It labels every quantifier to make greedy comparison easier in BFS
+	// approach.
+	__tmp._M_next = __next;
+	__tmp._M_alt = __alt;
+	__tmp._M_neg = __neg;
+	return _M_insert_state(std::move(__tmp));
+      }
+
+      _StateIdT
+      _M_insert_matcher(_MatcherT __m)
+      {
+	_StateT __tmp(_S_opcode_match);
+	__tmp._M_get_matcher() = std::move(__m);
+	return _M_insert_state(std::move(__tmp));
+      }
+
+      _StateIdT
+      _M_insert_subexpr_begin()
+      {
+	auto __id = this->_M_subexpr_count++;
+	this->_M_paren_stack.push_back(__id);
+	_StateT __tmp(_S_opcode_subexpr_begin);
+	__tmp._M_subexpr = __id;
+	return _M_insert_state(std::move(__tmp));
+      }
+
+      _StateIdT
+      _M_insert_subexpr_end()
+      {
+	_StateT __tmp(_S_opcode_subexpr_end);
+	__tmp._M_subexpr = this->_M_paren_stack.back();
+	this->_M_paren_stack.pop_back();
+	return _M_insert_state(std::move(__tmp));
+      }
+
+      _StateIdT
+      _M_insert_backref(size_t __index);
+
+      _StateIdT
+      _M_insert_line_begin()
+      { return _M_insert_state(_StateT(_S_opcode_line_begin_assertion)); }
+
+      _StateIdT
+      _M_insert_line_end()
+      { return _M_insert_state(_StateT(_S_opcode_line_end_assertion)); }
+
+      _StateIdT
+      _M_insert_word_bound(bool __neg)
+      {
+	_StateT __tmp(_S_opcode_word_boundary);
+	__tmp._M_neg = __neg;
+	return _M_insert_state(std::move(__tmp));
+      }
+
+      _StateIdT
+      _M_insert_lookahead(_StateIdT __alt, bool __neg)
+      {
+	_StateT __tmp(_S_opcode_subexpr_lookahead);
+	__tmp._M_alt = __alt;
+	__tmp._M_neg = __neg;
+	return _M_insert_state(std::move(__tmp));
+      }
+
+      _StateIdT
+      _M_insert_dummy()
+      { return _M_insert_state(_StateT(_S_opcode_dummy)); }
+
+      _StateIdT
+      _M_insert_state(_StateT __s)
+      {
+	this->push_back(std::move(__s));
+	if (this->size() > _GLIBCXX_REGEX_STATE_LIMIT)
+	  __throw_regex_error(
+	    regex_constants::error_space,
+	    "Number of NFA states exceeds limit. Please use shorter regex "
+	    "string, or use smaller brace expression, or make "
+	    "_GLIBCXX_REGEX_STATE_LIMIT larger.");
+	return this->size() - 1;
+      }
+
+      // Eliminate dummy node in this NFA to make it compact.
+      void
+      _M_eliminate_dummy();
+
+#ifdef _GLIBCXX_DEBUG
+      std::ostream&
+      _M_dot(std::ostream& __ostr) const;
+#endif
+    public:
+      _TraitsT                  _M_traits;
+    };
+
+  /// Describes a sequence of one or more %_State, its current start
+  /// and end(s).  This structure contains fragments of an NFA during
+  /// construction.
+  template<typename _TraitsT>
+    class _StateSeq
+    {
+    public:
+      typedef _NFA<_TraitsT> _RegexT;
+
+    public:
+      _StateSeq(_RegexT& __nfa, _StateIdT __s)
+      : _M_nfa(__nfa), _M_start(__s), _M_end(__s)
+      { }
+
+      _StateSeq(_RegexT& __nfa, _StateIdT __s, _StateIdT __end)
+      : _M_nfa(__nfa), _M_start(__s), _M_end(__end)
+      { }
+
+      // Append a state on *this and change *this to the new sequence.
+      void
+      _M_append(_StateIdT __id)
+      {
+	_M_nfa[_M_end]._M_next = __id;
+	_M_end = __id;
+      }
+
+      // Append a sequence on *this and change *this to the new sequence.
+      void
+      _M_append(const _StateSeq& __s)
+      {
+	_M_nfa[_M_end]._M_next = __s._M_start;
+	_M_end = __s._M_end;
+      }
+
+      // Clones an entire sequence.
+      _StateSeq
+      _M_clone();
+
+    public:
+      _RegexT&  _M_nfa;
+      _StateIdT _M_start;
+      _StateIdT _M_end;
+    };
+
+ ///@} regex-detail
+} // namespace __detail
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#include <bits/regex_automaton.tcc>
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@regex_automaton.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@regex_automaton.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@regex_automaton.tcc b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@regex_automaton.tcc
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--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@regex_automaton.tcc
@@ -0,0 +1,232 @@
+// class template regex -*- C++ -*-
+
+// Copyright (C) 2013-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/**
+ *  @file bits/regex_automaton.tcc
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{regex}
+ */
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+namespace __detail
+{
+#ifdef _GLIBCXX_DEBUG
+  inline std::ostream&
+  _State_base::_M_print(std::ostream& ostr) const
+  {
+    switch (_M_opcode)
+    {
+      case _S_opcode_alternative:
+      case _S_opcode_repeat:
+	ostr << "alt next=" << _M_next << " alt=" << _M_alt;
+	break;
+      case _S_opcode_subexpr_begin:
+	ostr << "subexpr begin next=" << _M_next << " index=" << _M_subexpr;
+	break;
+      case _S_opcode_subexpr_end:
+	ostr << "subexpr end next=" << _M_next << " index=" << _M_subexpr;
+	break;
+      case _S_opcode_backref:
+	ostr << "backref next=" << _M_next << " index=" << _M_backref_index;
+	break;
+      case _S_opcode_match:
+	ostr << "match next=" << _M_next;
+	break;
+      case _S_opcode_accept:
+	ostr << "accept next=" << _M_next;
+	break;
+      default:
+	ostr << "unknown next=" << _M_next;
+	break;
+    }
+    return ostr;
+  }
+
+  // Prints graphviz dot commands for state.
+  inline std::ostream&
+  _State_base::_M_dot(std::ostream& __ostr, _StateIdT __id) const
+  {
+    switch (_M_opcode)
+    {
+      case _S_opcode_alternative:
+      case _S_opcode_repeat:
+	__ostr << __id << " [label=\"" << __id << "\\nALT\"];\n"
+	       << __id << " -> " << _M_next
+	       << " [label=\"next\", tailport=\"s\"];\n"
+	       << __id << " -> " << _M_alt
+	       << " [label=\"alt\", tailport=\"n\"];\n";
+	break;
+      case _S_opcode_backref:
+	__ostr << __id << " [label=\"" << __id << "\\nBACKREF "
+	       << _M_subexpr << "\"];\n"
+	       << __id << " -> " << _M_next << " [label=\"<match>\"];\n";
+	break;
+      case _S_opcode_line_begin_assertion:
+	__ostr << __id << " [label=\"" << __id << "\\nLINE_BEGIN \"];\n"
+	       << __id << " -> " << _M_next << " [label=\"epsilon\"];\n";
+	break;
+      case _S_opcode_line_end_assertion:
+	__ostr << __id << " [label=\"" << __id << "\\nLINE_END \"];\n"
+	       << __id << " -> " << _M_next << " [label=\"epsilon\"];\n";
+	break;
+      case _S_opcode_word_boundary:
+	__ostr << __id << " [label=\"" << __id << "\\nWORD_BOUNDRY "
+	       << _M_neg << "\"];\n"
+	       << __id << " -> " << _M_next << " [label=\"epsilon\"];\n";
+	break;
+      case _S_opcode_subexpr_lookahead:
+	__ostr << __id << " [label=\"" << __id << "\\nLOOK_AHEAD\"];\n"
+	       << __id << " -> " << _M_next
+	       << " [label=\"epsilon\", tailport=\"s\"];\n"
+	       << __id << " -> " << _M_alt
+	       << " [label=\"<assert>\", tailport=\"n\"];\n";
+	break;
+      case _S_opcode_subexpr_begin:
+	__ostr << __id << " [label=\"" << __id << "\\nSBEGIN "
+	       << _M_subexpr << "\"];\n"
+	       << __id << " -> " << _M_next << " [label=\"epsilon\"];\n";
+	break;
+      case _S_opcode_subexpr_end:
+	__ostr << __id << " [label=\"" << __id << "\\nSEND "
+	       << _M_subexpr << "\"];\n"
+	       << __id << " -> " << _M_next << " [label=\"epsilon\"];\n";
+	break;
+      case _S_opcode_dummy:
+	break;
+      case _S_opcode_match:
+	__ostr << __id << " [label=\"" << __id << "\\nMATCH\"];\n"
+	       << __id << " -> " << _M_next << " [label=\"<match>\"];\n";
+	break;
+      case _S_opcode_accept:
+	__ostr << __id << " [label=\"" << __id << "\\nACC\"];\n" ;
+	break;
+      default:
+	_GLIBCXX_DEBUG_ASSERT(false);
+	break;
+    }
+    return __ostr;
+  }
+
+  template<typename _TraitsT>
+    std::ostream&
+    _NFA<_TraitsT>::_M_dot(std::ostream& __ostr) const
+    {
+      __ostr << "digraph _Nfa {\n"
+		"  rankdir=LR;\n";
+      for (size_t __i = 0; __i < this->size(); ++__i)
+	(*this)[__i]._M_dot(__ostr, __i);
+      __ostr << "}\n";
+      return __ostr;
+    }
+#endif
+
+  template<typename _TraitsT>
+    _StateIdT
+    _NFA<_TraitsT>::_M_insert_backref(size_t __index)
+    {
+      if (this->_M_flags & regex_constants::__polynomial)
+	__throw_regex_error(regex_constants::error_complexity,
+			    "Unexpected back-reference in polynomial mode.");
+      // To figure out whether a backref is valid, a stack is used to store
+      // unfinished sub-expressions. For example, when parsing
+      // "(a(b)(c\\1(d)))" at '\\1', _M_subexpr_count is 3, indicating that 3
+      // sub expressions are parsed or partially parsed(in the stack), aka,
+      // "(a..", "(b)" and "(c..").
+      // _M_paren_stack is {1, 3}, for incomplete "(a.." and "(c..". At this
+      // time, "\\2" is valid, but "\\1" and "\\3" are not.
+      if (__index >= _M_subexpr_count)
+	__throw_regex_error(
+	  regex_constants::error_backref,
+	  "Back-reference index exceeds current sub-expression count.");
+      for (auto __it : this->_M_paren_stack)
+	if (__index == __it)
+	  __throw_regex_error(
+	    regex_constants::error_backref,
+	    "Back-reference referred to an opened sub-expression.");
+      this->_M_has_backref = true;
+      _StateT __tmp(_S_opcode_backref);
+      __tmp._M_backref_index = __index;
+      return _M_insert_state(std::move(__tmp));
+    }
+
+  template<typename _TraitsT>
+    void
+    _NFA<_TraitsT>::_M_eliminate_dummy()
+    {
+      for (auto& __it : *this)
+	{
+	  while (__it._M_next >= 0 && (*this)[__it._M_next]._M_opcode()
+		 == _S_opcode_dummy)
+	    __it._M_next = (*this)[__it._M_next]._M_next;
+	  if (__it._M_has_alt())
+	    while (__it._M_alt >= 0 && (*this)[__it._M_alt]._M_opcode()
+		   == _S_opcode_dummy)
+	      __it._M_alt = (*this)[__it._M_alt]._M_next;
+	}
+    }
+
+  // Just apply DFS on the sequence and re-link their links.
+  template<typename _TraitsT>
+    _StateSeq<_TraitsT>
+    _StateSeq<_TraitsT>::_M_clone()
+    {
+      _GLIBCXX_STD_C::map<_StateIdT, _StateIdT> __m;
+      std::stack<_StateIdT, _GLIBCXX_STD_C::deque<_StateIdT>> __stack;
+      __stack.push(_M_start);
+      while (!__stack.empty())
+	{
+	  auto __u = __stack.top();
+	  __stack.pop();
+	  auto __dup = _M_nfa[__u];
+	  // _M_insert_state() never return -1
+	  auto __id = _M_nfa._M_insert_state(std::move(__dup));
+	  __m[__u] = __id;
+	  if (__dup._M_has_alt())
+	    if (__dup._M_alt != _S_invalid_state_id
+		&& __m.count(__dup._M_alt) == 0)
+	      __stack.push(__dup._M_alt);
+	  if (__u == _M_end)
+	    continue;
+	  if (__dup._M_next != _S_invalid_state_id
+	      && __m.count(__dup._M_next) == 0)
+	    __stack.push(__dup._M_next);
+	}
+      for (auto __it : __m)
+	{
+	  auto __v = __it.second;
+	  auto& __ref = _M_nfa[__v];
+	  if (__ref._M_next != _S_invalid_state_id)
+	    __ref._M_next = __m.find(__ref._M_next)->second;
+	  if (__ref._M_has_alt() && __ref._M_alt != _S_invalid_state_id)
+	    __ref._M_alt = __m.find(__ref._M_alt)->second;
+	}
+      return _StateSeq(_M_nfa, __m[_M_start], __m[_M_end]);
+    }
+} // namespace __detail
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@regex_automaton.tcc.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@regex_automaton.tcc.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@regex_compiler.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@regex_compiler.h
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@regex_compiler.h
@@ -0,0 +1,571 @@
+// class template regex -*- C++ -*-
+
+// Copyright (C) 2010-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/**
+ *  @file bits/regex_compiler.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{regex}
+ */
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+_GLIBCXX_BEGIN_NAMESPACE_CXX11
+
+  template<typename>
+    class regex_traits;
+
+_GLIBCXX_END_NAMESPACE_CXX11
+
+namespace __detail
+{
+  /**
+   * @addtogroup regex-detail
+   * @{
+   */
+
+  template<typename, bool, bool>
+    struct _BracketMatcher;
+
+  /**
+   * @brief Builds an NFA from an input iterator range.
+   *
+   * The %_TraitsT type should fulfill requirements [28.3].
+   */
+  template<typename _TraitsT>
+    class _Compiler
+    {
+    public:
+      typedef typename _TraitsT::char_type        _CharT;
+      typedef _NFA<_TraitsT>              	  _RegexT;
+      typedef regex_constants::syntax_option_type _FlagT;
+
+      _Compiler(const _CharT* __b, const _CharT* __e,
+		const typename _TraitsT::locale_type& __traits, _FlagT __flags);
+
+      shared_ptr<const _RegexT>
+      _M_get_nfa() noexcept
+      { return std::move(_M_nfa); }
+
+    private:
+      typedef _Scanner<_CharT>               _ScannerT;
+      typedef typename _TraitsT::string_type _StringT;
+      typedef typename _ScannerT::_TokenT    _TokenT;
+      typedef _StateSeq<_TraitsT>            _StateSeqT;
+      typedef std::stack<_StateSeqT>         _StackT;
+      typedef std::ctype<_CharT>             _CtypeT;
+
+      // accepts a specific token or returns false.
+      bool
+      _M_match_token(_TokenT __token);
+
+      void
+      _M_disjunction();
+
+      void
+      _M_alternative();
+
+      bool
+      _M_term();
+
+      bool
+      _M_assertion();
+
+      bool
+      _M_quantifier();
+
+      bool
+      _M_atom();
+
+      bool
+      _M_bracket_expression();
+
+      template<bool __icase, bool __collate>
+	void
+	_M_insert_any_matcher_ecma();
+
+      template<bool __icase, bool __collate>
+	void
+	_M_insert_any_matcher_posix();
+
+      template<bool __icase, bool __collate>
+	void
+	_M_insert_char_matcher();
+
+      template<bool __icase, bool __collate>
+	void
+	_M_insert_character_class_matcher();
+
+      template<bool __icase, bool __collate>
+	void
+	_M_insert_bracket_matcher(bool __neg);
+
+      // Cache of the last atom seen in a bracketed range expression.
+      struct _BracketState
+      {
+	enum class _Type : char { _None, _Char, _Class } _M_type = _Type::_None;
+	_CharT _M_char = _CharT();
+
+	void
+	set(_CharT __c) noexcept { _M_type = _Type::_Char; _M_char = __c; }
+
+	_GLIBCXX_NODISCARD _CharT
+	get() const noexcept { return _M_char; }
+
+	void
+	reset(_Type __t = _Type::_None) noexcept { _M_type = __t; }
+
+	explicit operator bool() const noexcept
+	{ return _M_type != _Type::_None; }
+
+	// Previous token was a single character.
+	_GLIBCXX_NODISCARD bool
+	_M_is_char() const noexcept { return _M_type == _Type::_Char; }
+
+	// Previous token was a character class, equivalent class,
+	// collating symbol etc.
+	_GLIBCXX_NODISCARD bool
+	_M_is_class() const noexcept { return _M_type == _Type::_Class; }
+      };
+
+      template<bool __icase, bool __collate>
+	using _BracketMatcher
+	  = std::__detail::_BracketMatcher<_TraitsT, __icase, __collate>;
+
+      // Returns true if successfully parsed one term and should continue
+      // compiling a bracket expression.
+      // Returns false if the compiler should move on.
+      template<bool __icase, bool __collate>
+	bool
+	_M_expression_term(_BracketState& __last_char,
+			   _BracketMatcher<__icase, __collate>& __matcher);
+
+      int
+      _M_cur_int_value(int __radix);
+
+      bool
+      _M_try_char();
+
+      _StateSeqT
+      _M_pop()
+      {
+	auto ret = _M_stack.top();
+	_M_stack.pop();
+	return ret;
+      }
+
+      static _FlagT
+      _S_validate(_FlagT __f)
+      {
+	using namespace regex_constants;
+	switch (__f & (ECMAScript|basic|extended|awk|grep|egrep))
+	  {
+	  case ECMAScript:
+	  case basic:
+	  case extended:
+	  case awk:
+	  case grep:
+	  case egrep:
+	    return __f;
+	  case _FlagT(0):
+	    return __f | ECMAScript;
+	  default:
+	    std::__throw_regex_error(_S_grammar, "conflicting grammar options");
+	  }
+      }
+
+      _FlagT              _M_flags;
+      _ScannerT           _M_scanner;
+      shared_ptr<_RegexT> _M_nfa;
+      _StringT            _M_value;
+      _StackT             _M_stack;
+      const _TraitsT&     _M_traits;
+      const _CtypeT&      _M_ctype;
+    };
+
+  // [28.13.14]
+  template<typename _TraitsT, bool __icase, bool __collate>
+    class _RegexTranslatorBase
+    {
+    public:
+      typedef typename _TraitsT::char_type	      _CharT;
+      typedef typename _TraitsT::string_type	      _StringT;
+      typedef _StringT _StrTransT;
+
+      explicit
+      _RegexTranslatorBase(const _TraitsT& __traits)
+      : _M_traits(__traits)
+      { }
+
+      _CharT
+      _M_translate(_CharT __ch) const
+      {
+	if _GLIBCXX17_CONSTEXPR (__icase)
+	  return _M_traits.translate_nocase(__ch);
+	else if _GLIBCXX17_CONSTEXPR (__collate)
+	  return _M_traits.translate(__ch);
+	else
+	  return __ch;
+      }
+
+      _StrTransT
+      _M_transform(_CharT __ch) const
+      {
+	_StrTransT __str(1, __ch);
+	return _M_traits.transform(__str.begin(), __str.end());
+      }
+
+      // See LWG 523. It's not efficiently implementable when _TraitsT is not
+      // std::regex_traits<>, and __collate is true. See specializations for
+      // implementations of other cases.
+      bool
+      _M_match_range(const _StrTransT& __first, const _StrTransT& __last,
+		     const _StrTransT& __s) const
+      { return __first <= __s && __s <= __last; }
+
+    protected:
+      bool _M_in_range_icase(_CharT __first, _CharT __last, _CharT __ch) const
+      {
+	typedef std::ctype<_CharT> __ctype_type;
+	const auto& __fctyp = use_facet<__ctype_type>(this->_M_traits.getloc());
+	auto __lower = __fctyp.tolower(__ch);
+	auto __upper = __fctyp.toupper(__ch);
+	return (__first <= __lower && __lower <= __last)
+	  || (__first <= __upper && __upper <= __last);
+      }
+
+      const _TraitsT& _M_traits;
+    };
+
+  template<typename _TraitsT, bool __icase, bool __collate>
+    class _RegexTranslator
+    : public _RegexTranslatorBase<_TraitsT, __icase, __collate>
+    {
+    public:
+      typedef _RegexTranslatorBase<_TraitsT, __icase, __collate> _Base;
+      using _Base::_Base;
+    };
+
+  template<typename _TraitsT, bool __icase>
+    class _RegexTranslator<_TraitsT, __icase, false>
+    : public _RegexTranslatorBase<_TraitsT, __icase, false>
+    {
+    public:
+      typedef _RegexTranslatorBase<_TraitsT, __icase, false> _Base;
+      typedef typename _Base::_CharT _CharT;
+      typedef _CharT _StrTransT;
+
+      using _Base::_Base;
+
+      _StrTransT
+      _M_transform(_CharT __ch) const
+      { return __ch; }
+
+      bool
+      _M_match_range(_CharT __first, _CharT __last, _CharT __ch) const
+      {
+	if _GLIBCXX17_CONSTEXPR (!__icase)
+	  return __first <= __ch && __ch <= __last;
+	else
+	  return this->_M_in_range_icase(__first, __last, __ch);
+      }
+    };
+
+  template<typename _CharType>
+    class _RegexTranslator<std::regex_traits<_CharType>, true, true>
+    : public _RegexTranslatorBase<std::regex_traits<_CharType>, true, true>
+    {
+    public:
+      typedef _RegexTranslatorBase<std::regex_traits<_CharType>, true, true>
+	_Base;
+      typedef typename _Base::_CharT _CharT;
+      typedef typename _Base::_StrTransT _StrTransT;
+
+      using _Base::_Base;
+
+      bool
+      _M_match_range(const _StrTransT& __first, const _StrTransT& __last,
+		     const _StrTransT& __str) const
+      {
+	__glibcxx_assert(__first.size() == 1);
+	__glibcxx_assert(__last.size() == 1);
+	__glibcxx_assert(__str.size() == 1);
+	return this->_M_in_range_icase(__first[0], __last[0], __str[0]);
+      }
+    };
+
+  template<typename _TraitsT>
+    class _RegexTranslator<_TraitsT, false, false>
+    {
+    public:
+      typedef typename _TraitsT::char_type _CharT;
+      typedef _CharT                       _StrTransT;
+
+      explicit
+      _RegexTranslator(const _TraitsT&)
+      { }
+
+      _CharT
+      _M_translate(_CharT __ch) const
+      { return __ch; }
+
+      _StrTransT
+      _M_transform(_CharT __ch) const
+      { return __ch; }
+
+      bool
+      _M_match_range(_CharT __first, _CharT __last, _CharT __ch) const
+      { return __first <= __ch && __ch <= __last; }
+    };
+
+  template<typename _TraitsT, bool __is_ecma, bool __icase, bool __collate>
+    struct _AnyMatcher;
+
+  template<typename _TraitsT, bool __icase, bool __collate>
+    struct _AnyMatcher<_TraitsT, false, __icase, __collate>
+    {
+      typedef _RegexTranslator<_TraitsT, __icase, __collate> _TransT;
+      typedef typename _TransT::_CharT                       _CharT;
+
+      explicit
+      _AnyMatcher(const _TraitsT& __traits)
+      : _M_translator(__traits)
+      { }
+
+      bool
+      operator()(_CharT __ch) const
+      {
+	static auto __nul = _M_translator._M_translate('\0');
+	return _M_translator._M_translate(__ch) != __nul;
+      }
+
+      _TransT _M_translator;
+    };
+
+  template<typename _TraitsT, bool __icase, bool __collate>
+    struct _AnyMatcher<_TraitsT, true, __icase, __collate>
+    {
+      typedef _RegexTranslator<_TraitsT, __icase, __collate> _TransT;
+      typedef typename _TransT::_CharT                       _CharT;
+
+      explicit
+      _AnyMatcher(const _TraitsT& __traits)
+      : _M_translator(__traits)
+      { }
+
+      bool
+      operator()(_CharT __ch) const
+      { return _M_apply(__ch, typename is_same<_CharT, char>::type()); }
+
+      bool
+      _M_apply(_CharT __ch, true_type) const
+      {
+	auto __c = _M_translator._M_translate(__ch);
+	auto __n = _M_translator._M_translate('\n');
+	auto __r = _M_translator._M_translate('\r');
+	return __c != __n && __c != __r;
+      }
+
+      bool
+      _M_apply(_CharT __ch, false_type) const
+      {
+	auto __c = _M_translator._M_translate(__ch);
+	auto __n = _M_translator._M_translate('\n');
+	auto __r = _M_translator._M_translate('\r');
+	auto __u2028 = _M_translator._M_translate(u'\u2028');
+	auto __u2029 = _M_translator._M_translate(u'\u2029');
+	return __c != __n && __c != __r && __c != __u2028 && __c != __u2029;
+      }
+
+      _TransT _M_translator;
+    };
+
+  template<typename _TraitsT, bool __icase, bool __collate>
+    struct _CharMatcher
+    {
+      typedef _RegexTranslator<_TraitsT, __icase, __collate> _TransT;
+      typedef typename _TransT::_CharT                       _CharT;
+
+      _CharMatcher(_CharT __ch, const _TraitsT& __traits)
+      : _M_translator(__traits), _M_ch(_M_translator._M_translate(__ch))
+      { }
+
+      bool
+      operator()(_CharT __ch) const
+      { return _M_ch == _M_translator._M_translate(__ch); }
+
+      _TransT _M_translator;
+      _CharT  _M_ch;
+    };
+
+  /// Matches a character range (bracket expression)
+  template<typename _TraitsT, bool __icase, bool __collate>
+    struct _BracketMatcher
+    {
+    public:
+      typedef _RegexTranslator<_TraitsT, __icase, __collate> _TransT;
+      typedef typename _TransT::_CharT                       _CharT;
+      typedef typename _TransT::_StrTransT                   _StrTransT;
+      typedef typename _TraitsT::string_type                 _StringT;
+      typedef typename _TraitsT::char_class_type             _CharClassT;
+
+    public:
+      _BracketMatcher(bool __is_non_matching,
+		      const _TraitsT& __traits)
+      : _M_class_set(0), _M_translator(__traits), _M_traits(__traits),
+      _M_is_non_matching(__is_non_matching)
+      { }
+
+      bool
+      operator()(_CharT __ch) const
+      {
+	_GLIBCXX_DEBUG_ASSERT(_M_is_ready);
+	return _M_apply(__ch, _UseCache());
+      }
+
+      void
+      _M_add_char(_CharT __c)
+      {
+	_M_char_set.push_back(_M_translator._M_translate(__c));
+	_GLIBCXX_DEBUG_ONLY(_M_is_ready = false);
+      }
+
+      _StringT
+      _M_add_collate_element(const _StringT& __s)
+      {
+	auto __st = _M_traits.lookup_collatename(__s.data(),
+						 __s.data() + __s.size());
+	if (__st.empty())
+	  __throw_regex_error(regex_constants::error_collate,
+			      "Invalid collate element.");
+	_M_char_set.push_back(_M_translator._M_translate(__st[0]));
+	_GLIBCXX_DEBUG_ONLY(_M_is_ready = false);
+	return __st;
+      }
+
+      void
+      _M_add_equivalence_class(const _StringT& __s)
+      {
+	auto __st = _M_traits.lookup_collatename(__s.data(),
+						 __s.data() + __s.size());
+	if (__st.empty())
+	  __throw_regex_error(regex_constants::error_collate,
+			      "Invalid equivalence class.");
+	__st = _M_traits.transform_primary(__st.data(),
+					   __st.data() + __st.size());
+	_M_equiv_set.push_back(__st);
+	_GLIBCXX_DEBUG_ONLY(_M_is_ready = false);
+      }
+
+      // __neg should be true for \D, \S and \W only.
+      void
+      _M_add_character_class(const _StringT& __s, bool __neg)
+      {
+	auto __mask = _M_traits.lookup_classname(__s.data(),
+						 __s.data() + __s.size(),
+						 __icase);
+	if (__mask == 0)
+	  __throw_regex_error(regex_constants::error_collate,
+			      "Invalid character class.");
+	if (!__neg)
+	  _M_class_set |= __mask;
+	else
+	  _M_neg_class_set.push_back(__mask);
+	_GLIBCXX_DEBUG_ONLY(_M_is_ready = false);
+      }
+
+      void
+      _M_make_range(_CharT __l, _CharT __r)
+      {
+	if (__l > __r)
+	  __throw_regex_error(regex_constants::error_range,
+			      "Invalid range in bracket expression.");
+	_M_range_set.push_back(make_pair(_M_translator._M_transform(__l),
+					 _M_translator._M_transform(__r)));
+	_GLIBCXX_DEBUG_ONLY(_M_is_ready = false);
+      }
+
+      void
+      _M_ready()
+      {
+	std::sort(_M_char_set.begin(), _M_char_set.end());
+	auto __end = std::unique(_M_char_set.begin(), _M_char_set.end());
+	_M_char_set.erase(__end, _M_char_set.end());
+	_M_make_cache(_UseCache());
+	_GLIBCXX_DEBUG_ONLY(_M_is_ready = true);
+      }
+
+    private:
+      // Currently we only use the cache for char
+      using _UseCache = typename std::is_same<_CharT, char>::type;
+
+      static constexpr size_t
+      _S_cache_size =
+	1ul << (sizeof(_CharT) * __CHAR_BIT__ * int(_UseCache::value));
+
+      struct _Dummy { };
+      using _CacheT = std::__conditional_t<_UseCache::value,
+					   std::bitset<_S_cache_size>,
+					   _Dummy>;
+      using _UnsignedCharT = typename std::make_unsigned<_CharT>::type;
+
+      bool
+      _M_apply(_CharT __ch, false_type) const;
+
+      bool
+      _M_apply(_CharT __ch, true_type) const
+      { return _M_cache[static_cast<_UnsignedCharT>(__ch)]; }
+
+      void
+      _M_make_cache(true_type)
+      {
+	for (unsigned __i = 0; __i < _M_cache.size(); __i++)
+	  _M_cache[__i] = _M_apply(static_cast<_CharT>(__i), false_type());
+      }
+
+      void
+      _M_make_cache(false_type)
+      { }
+
+    private:
+      _GLIBCXX_STD_C::vector<_CharT>            _M_char_set;
+      _GLIBCXX_STD_C::vector<_StringT>          _M_equiv_set;
+      _GLIBCXX_STD_C::vector<pair<_StrTransT, _StrTransT>> _M_range_set;
+      _GLIBCXX_STD_C::vector<_CharClassT>       _M_neg_class_set;
+      _CharClassT                               _M_class_set;
+      _TransT                                   _M_translator;
+      const _TraitsT&                           _M_traits;
+      bool                                      _M_is_non_matching;
+      _CacheT					_M_cache;
+#ifdef _GLIBCXX_DEBUG
+      bool                                      _M_is_ready = false;
+#endif
+    };
+
+ ///@} regex-detail
+} // namespace __detail
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#include <bits/regex_compiler.tcc>
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@regex_compiler.tcc b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@regex_compiler.tcc
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@@ -0,0 +1,622 @@
+// class template regex -*- C++ -*-
+
+// Copyright (C) 2013-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/**
+ *  @file bits/regex_compiler.tcc
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{regex}
+ */
+
+// FIXME make comments doxygen format.
+
+/*
+// This compiler refers to "Regular Expression Matching Can Be Simple And Fast"
+// (http://swtch.com/~rsc/regexp/regexp1.html),
+// but doesn't strictly follow it.
+//
+// When compiling, states are *chained* instead of tree- or graph-constructed.
+// It's more like structured programs: there's if statement and loop statement.
+//
+// For alternative structure (say "a|b"), aka "if statement", two branches
+// should be constructed. However, these two shall merge to an "end_tag" at
+// the end of this operator:
+//
+//                branch1
+//              /        \
+// => begin_tag            end_tag =>
+//              \        /
+//                branch2
+//
+// This is the difference between this implementation and that in Russ's
+// article.
+//
+// That's why we introduced dummy node here ------ "end_tag" is a dummy node.
+// All dummy nodes will be eliminated at the end of compilation.
+*/
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+namespace __detail
+{
+  template<typename _TraitsT>
+    _Compiler<_TraitsT>::
+    _Compiler(const _CharT* __b, const _CharT* __e,
+	      const typename _TraitsT::locale_type& __loc, _FlagT __flags)
+    : _M_flags(_S_validate(__flags)),
+      _M_scanner(__b, __e, _M_flags, __loc),
+      _M_nfa(make_shared<_RegexT>(__loc, _M_flags)),
+      _M_traits(_M_nfa->_M_traits),
+      _M_ctype(std::use_facet<_CtypeT>(__loc))
+    {
+      _StateSeqT __r(*_M_nfa, _M_nfa->_M_start());
+      __r._M_append(_M_nfa->_M_insert_subexpr_begin());
+      this->_M_disjunction();
+      if (!_M_match_token(_ScannerT::_S_token_eof))
+	__throw_regex_error(regex_constants::error_paren);
+      __r._M_append(_M_pop());
+      __glibcxx_assert(_M_stack.empty());
+      __r._M_append(_M_nfa->_M_insert_subexpr_end());
+      __r._M_append(_M_nfa->_M_insert_accept());
+      _M_nfa->_M_eliminate_dummy();
+    }
+
+  template<typename _TraitsT>
+    void
+    _Compiler<_TraitsT>::
+    _M_disjunction()
+    {
+      this->_M_alternative();
+      while (_M_match_token(_ScannerT::_S_token_or))
+	{
+	  _StateSeqT __alt1 = _M_pop();
+	  this->_M_alternative();
+	  _StateSeqT __alt2 = _M_pop();
+	  auto __end = _M_nfa->_M_insert_dummy();
+	  __alt1._M_append(__end);
+	  __alt2._M_append(__end);
+	  // __alt2 is state._M_next, __alt1 is state._M_alt. The executor
+	  // executes _M_alt before _M_next, as well as executing left
+	  // alternative before right one.
+	  _M_stack.push(_StateSeqT(*_M_nfa,
+				   _M_nfa->_M_insert_alt(
+				     __alt2._M_start, __alt1._M_start, false),
+				   __end));
+	}
+    }
+
+  template<typename _TraitsT>
+    void
+    _Compiler<_TraitsT>::
+    _M_alternative()
+    {
+      if (this->_M_term())
+	{
+	  _StateSeqT __re = _M_pop();
+	  this->_M_alternative();
+	  __re._M_append(_M_pop());
+	  _M_stack.push(__re);
+	}
+      else
+	_M_stack.push(_StateSeqT(*_M_nfa, _M_nfa->_M_insert_dummy()));
+    }
+
+  template<typename _TraitsT>
+    bool
+    _Compiler<_TraitsT>::
+    _M_term()
+    {
+      if (this->_M_assertion())
+	return true;
+      if (this->_M_atom())
+	{
+	  while (this->_M_quantifier())
+	    ;
+	  return true;
+	}
+      return false;
+    }
+
+  template<typename _TraitsT>
+    bool
+    _Compiler<_TraitsT>::
+    _M_assertion()
+    {
+      if (_M_match_token(_ScannerT::_S_token_line_begin))
+	_M_stack.push(_StateSeqT(*_M_nfa, _M_nfa->_M_insert_line_begin()));
+      else if (_M_match_token(_ScannerT::_S_token_line_end))
+	_M_stack.push(_StateSeqT(*_M_nfa, _M_nfa->_M_insert_line_end()));
+      else if (_M_match_token(_ScannerT::_S_token_word_bound))
+	// _M_value[0] == 'n' means it's negative, say "not word boundary".
+	_M_stack.push(_StateSeqT(*_M_nfa, _M_nfa->
+	      _M_insert_word_bound(_M_value[0] == 'n')));
+      else if (_M_match_token(_ScannerT::_S_token_subexpr_lookahead_begin))
+	{
+	  auto __neg = _M_value[0] == 'n';
+	  this->_M_disjunction();
+	  if (!_M_match_token(_ScannerT::_S_token_subexpr_end))
+	    __throw_regex_error(regex_constants::error_paren);
+	  auto __tmp = _M_pop();
+	  __tmp._M_append(_M_nfa->_M_insert_accept());
+	  _M_stack.push(
+	      _StateSeqT(
+		*_M_nfa,
+		_M_nfa->_M_insert_lookahead(__tmp._M_start, __neg)));
+	}
+      else
+	return false;
+      return true;
+    }
+
+  template<typename _TraitsT>
+    bool
+    _Compiler<_TraitsT>::
+    _M_quantifier()
+    {
+      bool __neg = (_M_flags & regex_constants::ECMAScript);
+      auto __init = [this, &__neg]()
+	{
+	  if (_M_stack.empty())
+	    __throw_regex_error(regex_constants::error_badrepeat);
+	  __neg = __neg && _M_match_token(_ScannerT::_S_token_opt);
+	};
+      if (_M_match_token(_ScannerT::_S_token_closure0))
+	{
+	  __init();
+	  auto __e = _M_pop();
+	  _StateSeqT __r(*_M_nfa,
+			 _M_nfa->_M_insert_repeat(_S_invalid_state_id,
+						  __e._M_start, __neg));
+	  __e._M_append(__r);
+	  _M_stack.push(__r);
+	}
+      else if (_M_match_token(_ScannerT::_S_token_closure1))
+	{
+	  __init();
+	  auto __e = _M_pop();
+	  __e._M_append(_M_nfa->_M_insert_repeat(_S_invalid_state_id,
+						 __e._M_start, __neg));
+	  _M_stack.push(__e);
+	}
+      else if (_M_match_token(_ScannerT::_S_token_opt))
+	{
+	  __init();
+	  auto __e = _M_pop();
+	  auto __end = _M_nfa->_M_insert_dummy();
+	  _StateSeqT __r(*_M_nfa,
+			 _M_nfa->_M_insert_repeat(_S_invalid_state_id,
+						  __e._M_start, __neg));
+	  __e._M_append(__end);
+	  __r._M_append(__end);
+	  _M_stack.push(__r);
+	}
+      else if (_M_match_token(_ScannerT::_S_token_interval_begin))
+	{
+	  if (_M_stack.empty())
+	    __throw_regex_error(regex_constants::error_badrepeat);
+	  if (!_M_match_token(_ScannerT::_S_token_dup_count))
+	    __throw_regex_error(regex_constants::error_badbrace);
+	  _StateSeqT __r(_M_pop());
+	  _StateSeqT __e(*_M_nfa, _M_nfa->_M_insert_dummy());
+	  long __min_rep = _M_cur_int_value(10);
+	  bool __infi = false;
+	  long __n = 0;
+
+	  // {3
+	  if (_M_match_token(_ScannerT::_S_token_comma))
+	    {
+	      if (_M_match_token(_ScannerT::_S_token_dup_count)) // {3,7}
+		__n = _M_cur_int_value(10) - __min_rep;
+	      else
+		__infi = true;
+	    }
+	  if (!_M_match_token(_ScannerT::_S_token_interval_end))
+	    __throw_regex_error(regex_constants::error_brace);
+
+	  __neg = __neg && _M_match_token(_ScannerT::_S_token_opt);
+
+	  for (long __i = 0; __i < __min_rep; ++__i)
+	    __e._M_append(__r._M_clone());
+
+	  if (__infi)
+	    {
+	      auto __tmp = __r._M_clone();
+	      _StateSeqT __s(*_M_nfa,
+			     _M_nfa->_M_insert_repeat(_S_invalid_state_id,
+						      __tmp._M_start, __neg));
+	      __tmp._M_append(__s);
+	      __e._M_append(__s);
+	    }
+	  else
+	    {
+	      if (__n < 0)
+		__throw_regex_error(regex_constants::error_badbrace);
+	      auto __end = _M_nfa->_M_insert_dummy();
+	      // _M_alt is the "match more" branch, and _M_next is the
+	      // "match less" one. Switch _M_alt and _M_next of all created
+	      // nodes. This is a hack but IMO works well.
+	      std::stack<_StateIdT> __stack;
+	      for (long __i = 0; __i < __n; ++__i)
+		{
+		  auto __tmp = __r._M_clone();
+		  auto __alt = _M_nfa->_M_insert_repeat(__tmp._M_start,
+							__end, __neg);
+		  __stack.push(__alt);
+		  __e._M_append(_StateSeqT(*_M_nfa, __alt, __tmp._M_end));
+		}
+	      __e._M_append(__end);
+	      while (!__stack.empty())
+		{
+		  auto& __tmp = (*_M_nfa)[__stack.top()];
+		  __stack.pop();
+		  std::swap(__tmp._M_next, __tmp._M_alt);
+		}
+	    }
+	  _M_stack.push(__e);
+	}
+      else
+	return false;
+      return true;
+    }
+
+#define __INSERT_REGEX_MATCHER(__func, ...)\
+	do {\
+	  if (!(_M_flags & regex_constants::icase))\
+	    if (!(_M_flags & regex_constants::collate))\
+	      __func<false, false>(__VA_ARGS__);\
+	    else\
+	      __func<false, true>(__VA_ARGS__);\
+	  else\
+	    if (!(_M_flags & regex_constants::collate))\
+	      __func<true, false>(__VA_ARGS__);\
+	    else\
+	      __func<true, true>(__VA_ARGS__);\
+	} while (false)
+
+  template<typename _TraitsT>
+    bool
+    _Compiler<_TraitsT>::
+    _M_atom()
+    {
+      if (_M_match_token(_ScannerT::_S_token_anychar))
+	{
+	  if (!(_M_flags & regex_constants::ECMAScript))
+	    __INSERT_REGEX_MATCHER(_M_insert_any_matcher_posix);
+	  else
+	    __INSERT_REGEX_MATCHER(_M_insert_any_matcher_ecma);
+	}
+      else if (_M_try_char())
+	__INSERT_REGEX_MATCHER(_M_insert_char_matcher);
+      else if (_M_match_token(_ScannerT::_S_token_backref))
+	_M_stack.push(_StateSeqT(*_M_nfa, _M_nfa->
+				 _M_insert_backref(_M_cur_int_value(10))));
+      else if (_M_match_token(_ScannerT::_S_token_quoted_class))
+	__INSERT_REGEX_MATCHER(_M_insert_character_class_matcher);
+      else if (_M_match_token(_ScannerT::_S_token_subexpr_no_group_begin))
+	{
+	  _StateSeqT __r(*_M_nfa, _M_nfa->_M_insert_dummy());
+	  this->_M_disjunction();
+	  if (!_M_match_token(_ScannerT::_S_token_subexpr_end))
+	    __throw_regex_error(regex_constants::error_paren);
+	  __r._M_append(_M_pop());
+	  _M_stack.push(__r);
+	}
+      else if (_M_match_token(_ScannerT::_S_token_subexpr_begin))
+	{
+	  _StateSeqT __r(*_M_nfa, _M_nfa->_M_insert_subexpr_begin());
+	  this->_M_disjunction();
+	  if (!_M_match_token(_ScannerT::_S_token_subexpr_end))
+	    __throw_regex_error(regex_constants::error_paren);
+	  __r._M_append(_M_pop());
+	  __r._M_append(_M_nfa->_M_insert_subexpr_end());
+	  _M_stack.push(__r);
+	}
+      else if (!_M_bracket_expression())
+	return false;
+      return true;
+    }
+
+  template<typename _TraitsT>
+    bool
+    _Compiler<_TraitsT>::
+    _M_bracket_expression()
+    {
+      bool __neg =
+	_M_match_token(_ScannerT::_S_token_bracket_neg_begin);
+      if (!(__neg || _M_match_token(_ScannerT::_S_token_bracket_begin)))
+	return false;
+      __INSERT_REGEX_MATCHER(_M_insert_bracket_matcher, __neg);
+      return true;
+    }
+#undef __INSERT_REGEX_MATCHER
+
+  template<typename _TraitsT>
+  template<bool __icase, bool __collate>
+    void
+    _Compiler<_TraitsT>::
+    _M_insert_any_matcher_ecma()
+    {
+      _M_stack.push(_StateSeqT(*_M_nfa,
+	_M_nfa->_M_insert_matcher
+	  (_AnyMatcher<_TraitsT, true, __icase, __collate>
+	    (_M_traits))));
+    }
+
+  template<typename _TraitsT>
+  template<bool __icase, bool __collate>
+    void
+    _Compiler<_TraitsT>::
+    _M_insert_any_matcher_posix()
+    {
+      _M_stack.push(_StateSeqT(*_M_nfa,
+	_M_nfa->_M_insert_matcher
+	  (_AnyMatcher<_TraitsT, false, __icase, __collate>
+	    (_M_traits))));
+    }
+
+  template<typename _TraitsT>
+  template<bool __icase, bool __collate>
+    void
+    _Compiler<_TraitsT>::
+    _M_insert_char_matcher()
+    {
+      _M_stack.push(_StateSeqT(*_M_nfa,
+	_M_nfa->_M_insert_matcher
+	  (_CharMatcher<_TraitsT, __icase, __collate>
+	    (_M_value[0], _M_traits))));
+    }
+
+  template<typename _TraitsT>
+  template<bool __icase, bool __collate>
+    void
+    _Compiler<_TraitsT>::
+    _M_insert_character_class_matcher()
+    {
+      __glibcxx_assert(_M_value.size() == 1);
+      _BracketMatcher<__icase, __collate> __matcher
+	(_M_ctype.is(_CtypeT::upper, _M_value[0]), _M_traits);
+      __matcher._M_add_character_class(_M_value, false);
+      __matcher._M_ready();
+      _M_stack.push(_StateSeqT(*_M_nfa,
+	_M_nfa->_M_insert_matcher(std::move(__matcher))));
+    }
+
+  template<typename _TraitsT>
+  template<bool __icase, bool __collate>
+    void
+    _Compiler<_TraitsT>::
+    _M_insert_bracket_matcher(bool __neg)
+    {
+      _BracketMatcher<__icase, __collate> __matcher(__neg, _M_traits);
+      _BracketState __last_char;
+      if (_M_try_char())
+	__last_char.set(_M_value[0]);
+      else if (_M_match_token(_ScannerT::_S_token_bracket_dash))
+	// Dash as first character is a normal character.
+	__last_char.set('-');
+      while (_M_expression_term(__last_char, __matcher))
+	;
+      if (__last_char._M_is_char())
+	__matcher._M_add_char(__last_char.get());
+      __matcher._M_ready();
+      _M_stack.push(_StateSeqT(
+		      *_M_nfa,
+		      _M_nfa->_M_insert_matcher(std::move(__matcher))));
+    }
+
+  template<typename _TraitsT>
+  template<bool __icase, bool __collate>
+    bool
+    _Compiler<_TraitsT>::
+    _M_expression_term(_BracketState& __last_char,
+		       _BracketMatcher<__icase, __collate>& __matcher)
+    {
+      if (_M_match_token(_ScannerT::_S_token_bracket_end))
+	return false;
+
+      // Add any previously cached char into the matcher and update cache.
+      const auto __push_char = [&](_CharT __ch)
+      {
+	if (__last_char._M_is_char())
+	  __matcher._M_add_char(__last_char.get());
+	__last_char.set(__ch);
+      };
+      // Add any previously cached char into the matcher and update cache.
+      const auto __push_class = [&]
+      {
+        if (__last_char._M_is_char())
+	  __matcher._M_add_char(__last_char.get());
+	// We don't cache anything here, just record that the last thing
+	// processed was a character class (or similar).
+	__last_char.reset(_BracketState::_Type::_Class);
+      };
+
+      if (_M_match_token(_ScannerT::_S_token_collsymbol))
+	{
+	  auto __symbol = __matcher._M_add_collate_element(_M_value);
+	  if (__symbol.size() == 1)
+	    __push_char(__symbol[0]);
+	  else
+	    __push_class();
+	}
+      else if (_M_match_token(_ScannerT::_S_token_equiv_class_name))
+	{
+	  __push_class();
+	  __matcher._M_add_equivalence_class(_M_value);
+	}
+      else if (_M_match_token(_ScannerT::_S_token_char_class_name))
+	{
+	  __push_class();
+	  __matcher._M_add_character_class(_M_value, false);
+	}
+      else if (_M_try_char())
+	__push_char(_M_value[0]);
+      // POSIX doesn't allow '-' as a start-range char (say [a-z--0]),
+      // except when the '-' is the first or last character in the bracket
+      // expression ([--0]). ECMAScript treats all '-' after a range as a
+      // normal character. Also see above, where _M_expression_term gets called.
+      //
+      // As a result, POSIX rejects [-----], but ECMAScript doesn't.
+      // Boost (1.57.0) always uses POSIX style even in its ECMAScript syntax.
+      // Clang (3.5) always uses ECMAScript style even in its POSIX syntax.
+      //
+      // It turns out that no one reads BNFs ;)
+      else if (_M_match_token(_ScannerT::_S_token_bracket_dash))
+	{
+	  if (_M_match_token(_ScannerT::_S_token_bracket_end))
+	    {
+	      // For "-]" the dash is a literal character.
+	      __push_char('-');
+	      return false;
+	    }
+	  else if (__last_char._M_is_class())
+	    {
+	      // "\\w-" is invalid, start of range must be a single char.
+	      __throw_regex_error(regex_constants::error_range,
+				  "Invalid start of '[x-x]' range in "
+				  "regular expression");
+	    }
+	  else if (__last_char._M_is_char())
+	    {
+	      if (_M_try_char())
+		{
+		  // "x-y"
+		  __matcher._M_make_range(__last_char.get(), _M_value[0]);
+		  __last_char.reset();
+		}
+	      else if (_M_match_token(_ScannerT::_S_token_bracket_dash))
+		{
+		  // "x--"
+		  __matcher._M_make_range(__last_char.get(), '-');
+		  __last_char.reset();
+		}
+	      else
+		__throw_regex_error(regex_constants::error_range,
+				    "Invalid end of '[x-x]' range in "
+				    "regular expression");
+	    }
+	  else if (_M_flags & regex_constants::ECMAScript)
+	    {
+	      // A dash that is not part of an existing range. Might be the
+	      // start of a new range, or might just be a literal '-' char.
+	      // Only ECMAScript allows that in the middle of a bracket expr.
+	      __push_char('-');
+	    }
+	  else
+	    __throw_regex_error(regex_constants::error_range,
+				"Invalid location of '-' within '[...]' in "
+				"POSIX regular expression");
+	}
+      else if (_M_match_token(_ScannerT::_S_token_quoted_class))
+	{
+	  __push_class();
+	  __matcher._M_add_character_class(_M_value,
+					   _M_ctype.is(_CtypeT::upper,
+						       _M_value[0]));
+	}
+      else
+	__throw_regex_error(regex_constants::error_brack,
+			    "Unexpected character within '[...]' in "
+			    "regular expression");
+      return true;
+    }
+
+  template<typename _TraitsT>
+    bool
+    _Compiler<_TraitsT>::
+    _M_try_char()
+    {
+      bool __is_char = false;
+      if (_M_match_token(_ScannerT::_S_token_oct_num))
+	{
+	  __is_char = true;
+	  _M_value.assign(1, _M_cur_int_value(8));
+	}
+      else if (_M_match_token(_ScannerT::_S_token_hex_num))
+	{
+	  __is_char = true;
+	  _M_value.assign(1, _M_cur_int_value(16));
+	}
+      else if (_M_match_token(_ScannerT::_S_token_ord_char))
+	__is_char = true;
+      return __is_char;
+    }
+
+  template<typename _TraitsT>
+    bool
+    _Compiler<_TraitsT>::
+    _M_match_token(_TokenT __token)
+    {
+      if (__token == _M_scanner._M_get_token())
+	{
+	  _M_value = _M_scanner._M_get_value();
+	  _M_scanner._M_advance();
+	  return true;
+	}
+      return false;
+    }
+
+  template<typename _TraitsT>
+    int
+    _Compiler<_TraitsT>::
+    _M_cur_int_value(int __radix)
+    {
+      long __v = 0;
+      for (typename _StringT::size_type __i = 0;
+	   __i < _M_value.length(); ++__i)
+	__v =__v * __radix + _M_traits.value(_M_value[__i], __radix);
+      return __v;
+    }
+
+  template<typename _TraitsT, bool __icase, bool __collate>
+    bool
+    _BracketMatcher<_TraitsT, __icase, __collate>::
+    _M_apply(_CharT __ch, false_type) const
+    {
+      return [this, __ch]
+      {
+	if (std::binary_search(_M_char_set.begin(), _M_char_set.end(),
+			       _M_translator._M_translate(__ch)))
+	  return true;
+	auto __s = _M_translator._M_transform(__ch);
+	for (auto& __it : _M_range_set)
+	  if (_M_translator._M_match_range(__it.first, __it.second, __s))
+	    return true;
+	if (_M_traits.isctype(__ch, _M_class_set))
+	  return true;
+	if (std::find(_M_equiv_set.begin(), _M_equiv_set.end(),
+		      _M_traits.transform_primary(&__ch, &__ch+1))
+	    != _M_equiv_set.end())
+	  return true;
+	for (auto& __it : _M_neg_class_set)
+	  if (!_M_traits.isctype(__ch, __it))
+	    return true;
+	return false;
+      }() ^ _M_is_non_matching;
+    }
+} // namespace __detail
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
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@@ -0,0 +1,413 @@
+// class template regex -*- C++ -*-
+
+// Copyright (C) 2010-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/**
+ *  @file bits/regex_constants.h
+ *  @brief Constant definitions for the std regex library.
+ *
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{regex}
+ */
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+/**
+ * @defgroup regex Regular Expressions
+ *
+ * A facility for performing regular expression pattern matching.
+ * @{
+ */
+
+/**
+ * @namespace std::regex_constants
+ * @brief ISO C++ 2011 namespace for options and flags used with std::regex
+ */
+namespace regex_constants
+{
+  /**
+   * @name 5.1 Regular Expression Syntax Options
+   */
+  ///@{
+
+  /**
+   * @brief This is a bitmask type indicating how to interpret the regex.
+   *
+   * The @c syntax_option_type is implementation defined but it is valid to
+   * perform bitwise operations on these values and expect the right thing to
+   * happen.
+   *
+   * A valid value of type syntax_option_type shall have exactly one of the
+   * elements @c ECMAScript, @c basic, @c extended, @c awk, @c grep, @c egrep
+   * %set.
+   */
+  enum syntax_option_type : unsigned int
+  {
+    _S_icase		= 1 << 0,
+    _S_nosubs		= 1 << 1,
+    _S_optimize		= 1 << 2,
+    _S_collate		= 1 << 3,
+    _S_ECMAScript	= 1 << 4,
+    _S_basic		= 1 << 5,
+    _S_extended		= 1 << 6,
+    _S_awk		= 1 << 7,
+    _S_grep		= 1 << 8,
+    _S_egrep		= 1 << 9,
+    _S_polynomial	= 1 << 10,
+    _S_multiline	= 1 << 11
+  };
+
+  /**
+   * Specifies that the matching of regular expressions against a character
+   * sequence shall be performed without regard to case.
+   */
+  _GLIBCXX17_INLINE constexpr syntax_option_type icase = _S_icase;
+
+  /**
+   * Specifies that when a regular expression is matched against a character
+   * container sequence, no sub-expression matches are to be stored in the
+   * supplied match_results structure.
+   */
+  _GLIBCXX17_INLINE constexpr syntax_option_type nosubs = _S_nosubs;
+
+  /**
+   * Specifies that the regular expression engine should pay more attention to
+   * the speed with which regular expressions are matched, and less to the
+   * speed with which regular expression objects are constructed. Otherwise
+   * it has no detectable effect on the program output.
+   */
+  _GLIBCXX17_INLINE constexpr syntax_option_type optimize = _S_optimize;
+
+  /**
+   * Specifies that character ranges of the form [a-b] should be locale
+   * sensitive.
+   */
+  _GLIBCXX17_INLINE constexpr syntax_option_type collate = _S_collate;
+
+  /**
+   * Specifies that the grammar recognized by the regular expression engine is
+   * that used by ECMAScript in ECMA-262 [Ecma International, ECMAScript
+   * Language Specification, Standard Ecma-262, third edition, 1999], as
+   * modified in section [28.13].  This grammar is similar to that defined
+   * in the PERL scripting language but extended with elements found in the
+   * POSIX regular expression grammar.
+   */
+  _GLIBCXX17_INLINE constexpr syntax_option_type ECMAScript = _S_ECMAScript;
+
+  /**
+   * Specifies that the grammar recognized by the regular expression engine is
+   * that used by POSIX basic regular expressions in IEEE Std 1003.1-2001,
+   * Portable Operating System Interface (POSIX), Base Definitions and
+   * Headers, Section 9, Regular Expressions [IEEE, Information Technology --
+   * Portable Operating System Interface (POSIX), IEEE Standard 1003.1-2001].
+   */
+  _GLIBCXX17_INLINE constexpr syntax_option_type basic = _S_basic;
+
+  /**
+   * Specifies that the grammar recognized by the regular expression engine is
+   * that used by POSIX extended regular expressions in IEEE Std 1003.1-2001,
+   * Portable Operating System Interface (POSIX), Base Definitions and
+   * Headers, Section 9, Regular Expressions.
+   */
+  _GLIBCXX17_INLINE constexpr syntax_option_type extended = _S_extended;
+
+  /**
+   * Specifies that the grammar recognized by the regular expression engine is
+   * that used by POSIX utility awk in IEEE Std 1003.1-2001.  This option is
+   * identical to syntax_option_type extended, except that C-style escape
+   * sequences are supported.  These sequences are:
+   * \\\\, \\a, \\b, \\f, \\n, \\r, \\t , \\v, \\&apos,, &apos,,
+   * and \\ddd (where ddd is one, two, or three octal digits).
+   */
+  _GLIBCXX17_INLINE constexpr syntax_option_type awk = _S_awk;
+
+  /**
+   * Specifies that the grammar recognized by the regular expression engine is
+   * that used by POSIX utility grep in IEEE Std 1003.1-2001.  This option is
+   * identical to syntax_option_type basic, except that newlines are treated
+   * as whitespace.
+   */
+  _GLIBCXX17_INLINE constexpr syntax_option_type grep = _S_grep;
+
+  /**
+   * Specifies that the grammar recognized by the regular expression engine is
+   * that used by POSIX utility grep when given the -E option in
+   * IEEE Std 1003.1-2001.  This option is identical to syntax_option_type
+   * extended, except that newlines are treated as whitespace.
+   */
+  _GLIBCXX17_INLINE constexpr syntax_option_type egrep = _S_egrep;
+
+#if __cplusplus >= 201703L || !defined __STRICT_ANSI__
+  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+  // 2503. multiline option should be added to syntax_option_type
+  /**
+   * Specifies that the `^` anchor matches at the beginning of a line,
+   * and the `$` anchor matches at the end of a line, not only at the
+   * beginning/end of the input.
+   * Valid for the ECMAScript syntax, ignored otherwise.
+   * @since C++17
+   */
+  _GLIBCXX17_INLINE constexpr syntax_option_type multiline = _S_multiline;
+#endif
+
+  /// Extension: Equivalent to regex_constants::multiline for C++11 and C++14.
+  _GLIBCXX17_INLINE constexpr syntax_option_type __multiline = _S_multiline;
+
+  /**
+   * Extension: Ensure both space complexity of compiled regex and
+   * time complexity execution are not exponential.
+   * If specified in a regex with back-references, the exception
+   * regex_constants::error_complexity will be thrown.
+   */
+  _GLIBCXX17_INLINE constexpr syntax_option_type __polynomial = _S_polynomial;
+
+  constexpr inline syntax_option_type
+  operator&(syntax_option_type __a, syntax_option_type __b)
+  {
+    return (syntax_option_type)(static_cast<unsigned int>(__a)
+				& static_cast<unsigned int>(__b));
+  }
+
+  constexpr inline syntax_option_type
+  operator|(syntax_option_type __a, syntax_option_type __b)
+  {
+    return (syntax_option_type)(static_cast<unsigned int>(__a)
+				| static_cast<unsigned int>(__b));
+  }
+
+  constexpr inline syntax_option_type
+  operator^(syntax_option_type __a, syntax_option_type __b)
+  {
+    return (syntax_option_type)(static_cast<unsigned int>(__a)
+				^ static_cast<unsigned int>(__b));
+  }
+
+  constexpr inline syntax_option_type
+  operator~(syntax_option_type __a)
+  { return (syntax_option_type)(~static_cast<unsigned int>(__a)); }
+
+  _GLIBCXX14_CONSTEXPR
+  inline syntax_option_type&
+  operator&=(syntax_option_type& __a, syntax_option_type __b)
+  { return __a = __a & __b; }
+
+  _GLIBCXX14_CONSTEXPR
+  inline syntax_option_type&
+  operator|=(syntax_option_type& __a, syntax_option_type __b)
+  { return __a = __a | __b; }
+
+  _GLIBCXX14_CONSTEXPR
+  inline syntax_option_type&
+  operator^=(syntax_option_type& __a, syntax_option_type __b)
+  { return __a = __a ^ __b; }
+
+  ///@}
+
+  /**
+   * @name 5.2 Matching Rules
+   *
+   * Matching a regular expression against a sequence of characters [first,
+   * last) proceeds according to the rules of the grammar specified for the
+   * regular expression object, modified according to the effects listed
+   * below for any bitmask elements set.
+   *
+   */
+  ///@{
+
+  /**
+   * @brief This is a bitmask type indicating regex matching rules.
+   *
+   * The @c match_flag_type is implementation defined but it is valid to
+   * perform bitwise operations on these values and expect the right thing to
+   * happen.
+   */
+  enum match_flag_type : unsigned int
+  {
+    _S_default,
+    _S_not_bol		= 1 << 0,
+    _S_not_eol		= 1 << 1,
+    _S_not_bow		= 1 << 2,
+    _S_not_eow		= 1 << 3,
+    _S_any		= 1 << 4,
+    _S_not_null		= 1 << 5,
+    _S_continuous	= 1 << 6,
+    _S_prev_avail	= 1 << 7,
+    _S_sed		= 1 << 8,
+    _S_no_copy		= 1 << 9,
+    _S_first_only	= 1 << 10,
+    _S_match_flag_last	= 1 << 11
+  };
+
+  /**
+   * The default matching rules.
+   */
+  _GLIBCXX17_INLINE constexpr match_flag_type match_default = _S_default;
+
+  /**
+   * The first character in the sequence [first, last) is treated as though it
+   * is not at the beginning of a line, so the character (^) in the regular
+   * expression shall not match [first, first).
+   */
+  _GLIBCXX17_INLINE constexpr match_flag_type match_not_bol = _S_not_bol;
+
+  /**
+   * The last character in the sequence [first, last) is treated as though it
+   * is not at the end of a line, so the character ($) in the regular
+   * expression shall not match [last, last).
+   */
+  _GLIBCXX17_INLINE constexpr match_flag_type match_not_eol = _S_not_eol;
+
+  /**
+   * The expression \\b is not matched against the sub-sequence
+   * [first,first).
+   */
+  _GLIBCXX17_INLINE constexpr match_flag_type match_not_bow = _S_not_bow;
+
+  /**
+   * The expression \\b should not be matched against the sub-sequence
+   * [last,last).
+   */
+  _GLIBCXX17_INLINE constexpr match_flag_type match_not_eow = _S_not_eow;
+
+  /**
+   * If more than one match is possible then any match is an acceptable
+   * result.
+   */
+  _GLIBCXX17_INLINE constexpr match_flag_type match_any = _S_any;
+
+  /**
+   * The expression does not match an empty sequence.
+   */
+  _GLIBCXX17_INLINE constexpr match_flag_type match_not_null = _S_not_null;
+
+  /**
+   * The expression only matches a sub-sequence that begins at first .
+   */
+  _GLIBCXX17_INLINE constexpr match_flag_type match_continuous = _S_continuous;
+
+  /**
+   * `--first` is a valid iterator position.  When this flag is set then the
+   * flags `match_not_bol` and `match_not_bow` are ignored by the algorithms
+   * `regex_match`, `regex_search`, and `regex_replace`, and by the iterators
+   * `regex_iterator` and `regex_token_iterator`.
+   */
+  _GLIBCXX17_INLINE constexpr match_flag_type match_prev_avail = _S_prev_avail;
+
+  /**
+   * When a regular expression match is to be replaced by a new string, the
+   * new string is constructed using the rules used by the ECMAScript replace
+   * function in ECMA- 262 [Ecma International, ECMAScript Language
+   * Specification, Standard Ecma-262, third edition, 1999], part 15.5.4.11
+   * String.prototype.replace. In addition, during search and replace
+   * operations all non-overlapping occurrences of the regular expression
+   * are located and replaced, and sections of the input that did not match
+   * the expression are copied unchanged to the output string.
+   *
+   * Format strings (from ECMA-262 [15.5.4.11]):
+   * @li $$  The dollar-sign itself ($)
+   * @li $&  The matched substring.
+   * @li $`  The portion of @a string that precedes the matched substring.
+   *         This would be match_results::prefix().
+   * @li $'  The portion of @a string that follows the matched substring.
+   *         This would be match_results::suffix().
+   * @li $n  The nth capture, where n is in [1,9] and $n is not followed by a
+   *         decimal digit.  If n <= match_results::size() and the nth capture
+   *         is undefined, use the empty string instead.  If n >
+   *         match_results::size(), the result is implementation-defined.
+   * @li $nn The nnth capture, where nn is a two-digit decimal number on
+   *         [01, 99].  If nn <= match_results::size() and the nth capture is
+   *         undefined, use the empty string instead. If
+   *         nn > match_results::size(), the result is implementation-defined.
+   */
+  _GLIBCXX17_INLINE constexpr match_flag_type format_default = _S_default;
+
+  /**
+   * When a regular expression match is to be replaced by a new string, the
+   * new string is constructed using the rules used by the POSIX sed utility
+   * in IEEE Std 1003.1- 2001 [IEEE, Information Technology -- Portable
+   * Operating System Interface (POSIX), IEEE Standard 1003.1-2001].
+   */
+  _GLIBCXX17_INLINE constexpr match_flag_type format_sed = _S_sed;
+
+  /**
+   * During a search and replace operation, sections of the character
+   * container sequence being searched that do not match the regular
+   * expression shall not be copied to the output string.
+   */
+  _GLIBCXX17_INLINE constexpr match_flag_type format_no_copy = _S_no_copy;
+
+  /**
+   * When specified during a search and replace operation, only the first
+   * occurrence of the regular expression shall be replaced.
+   */
+  _GLIBCXX17_INLINE constexpr match_flag_type format_first_only = _S_first_only;
+
+  constexpr inline match_flag_type
+  operator&(match_flag_type __a, match_flag_type __b)
+  {
+    return (match_flag_type)(static_cast<unsigned int>(__a)
+				& static_cast<unsigned int>(__b));
+  }
+
+  constexpr inline match_flag_type
+  operator|(match_flag_type __a, match_flag_type __b)
+  {
+    return (match_flag_type)(static_cast<unsigned int>(__a)
+				| static_cast<unsigned int>(__b));
+  }
+
+  constexpr inline match_flag_type
+  operator^(match_flag_type __a, match_flag_type __b)
+  {
+    return (match_flag_type)(static_cast<unsigned int>(__a)
+				^ static_cast<unsigned int>(__b));
+  }
+
+  constexpr inline match_flag_type
+  operator~(match_flag_type __a)
+  { return (match_flag_type)(~static_cast<unsigned int>(__a)); }
+
+  _GLIBCXX14_CONSTEXPR
+  inline match_flag_type&
+  operator&=(match_flag_type& __a, match_flag_type __b)
+  { return __a = __a & __b; }
+
+  _GLIBCXX14_CONSTEXPR
+  inline match_flag_type&
+  operator|=(match_flag_type& __a, match_flag_type __b)
+  { return __a = __a | __b; }
+
+  _GLIBCXX14_CONSTEXPR
+  inline match_flag_type&
+  operator^=(match_flag_type& __a, match_flag_type __b)
+  { return __a = __a ^ __b; }
+
+  ///@}
+} // namespace regex_constants
+/// @} group regex
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
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+// class template regex -*- C++ -*-
+
+// Copyright (C) 2010-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/**
+ * @file bits/regex_error.h
+ * @brief Error and exception objects for the std regex library.
+ *
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{regex}
+ */
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+/**
+ * @addtogroup regex
+ * @{
+ */
+
+namespace regex_constants
+{
+  /**
+   * @name 5.3 Error Types
+   */
+  ///@{
+
+  enum error_type
+    {
+      _S_error_collate, // XXX should have been a non-zero value
+      _S_error_ctype,
+      _S_error_escape,
+      _S_error_backref,
+      _S_error_brack,
+      _S_error_paren,
+      _S_error_brace,
+      _S_error_badbrace,
+      _S_error_range,
+      _S_error_space,
+      _S_error_badrepeat,
+      _S_error_complexity,
+      _S_error_stack,
+      _S_null,
+      _S_grammar
+    };
+
+  /** The expression contained an invalid collating element name. */
+  constexpr error_type error_collate(_S_error_collate);
+
+  /** The expression contained an invalid character class name. */
+  constexpr error_type error_ctype(_S_error_ctype);
+
+  /**
+   * The expression contained an invalid escaped character, or a trailing
+   * escape.
+   */
+  constexpr error_type error_escape(_S_error_escape);
+
+  /** The expression contained an invalid back reference. */
+  constexpr error_type error_backref(_S_error_backref);
+
+  /** The expression contained mismatched [ and ]. */
+  constexpr error_type error_brack(_S_error_brack);
+
+  /** The expression contained mismatched ( and ). */
+  constexpr error_type error_paren(_S_error_paren);
+
+  /** The expression contained mismatched { and } */
+  constexpr error_type error_brace(_S_error_brace);
+
+  /** The expression contained an invalid range in a {} expression. */
+  constexpr error_type error_badbrace(_S_error_badbrace);
+
+  /**
+   * The expression contained an invalid character range,
+   * such as [b-a] in most encodings.
+   */
+  constexpr error_type error_range(_S_error_range);
+
+  /**
+   * There was insufficient memory to convert the expression into a
+   * finite state machine.
+   */
+  constexpr error_type error_space(_S_error_space);
+
+  /**
+   * One of <em>*?+{</em> was not preceded by a valid regular expression.
+   */
+  constexpr error_type error_badrepeat(_S_error_badrepeat);
+
+  /**
+   * The complexity of an attempted match against a regular expression
+   * exceeded a pre-set level.
+   */
+  constexpr error_type error_complexity(_S_error_complexity);
+
+  /**
+   * There was insufficient memory to determine whether the
+   * regular expression could match the specified character sequence.
+   */
+  constexpr error_type error_stack(_S_error_stack);
+
+  ///@}
+} // namespace regex_constants
+
+  // [7.8] Class regex_error
+  /**
+   * @brief A regular expression exception class.
+   * @ingroup exceptions
+   *
+   * The regular expression library throws objects of this class on error.
+   */
+  class regex_error : public std::runtime_error
+  {
+    using error_type = regex_constants::error_type;
+
+    error_type _M_code;
+
+  public:
+    /**
+     * @brief Constructs a regex_error object.
+     *
+     * @param __ecode the regex error code.
+     */
+    explicit
+    regex_error(error_type __ecode);
+
+    virtual ~regex_error() throw();
+
+    /**
+     * @brief Gets the regex error code.
+     *
+     * @returns the regex error code.
+     */
+    regex_constants::error_type
+    code() const noexcept
+    { return _M_code; }
+
+  private:
+    regex_error(error_type __ecode, const char* __what)
+    : std::runtime_error(__what), _M_code(__ecode)
+    { }
+
+    [[__noreturn__]]
+    friend void
+    __throw_regex_error(error_type __ecode __attribute__((__unused__)),
+			const char* __what __attribute__((__unused__)))
+    { _GLIBCXX_THROW_OR_ABORT(regex_error(__ecode, __what)); }
+  };
+
+  /// @cond undocumented
+
+  [[__noreturn__]]
+  void
+  __throw_regex_error(regex_constants::error_type __ecode);
+
+  [[__noreturn__]]
+  inline void
+  __throw_regex_error(regex_constants::error_type __ecode, const char* __what);
+
+  /// @endcond
+
+  ///@} // group regex
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
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@@ -0,0 +1,311 @@
+// class template regex -*- C++ -*-
+
+// Copyright (C) 2013-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/**
+ *  @file bits/regex_executor.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{regex}
+ */
+
+// FIXME convert comments to doxygen format.
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+namespace __detail
+{
+  /**
+   * @addtogroup regex-detail
+   * @{
+   */
+
+  /**
+   * @brief Takes a regex and an input string and does the matching.
+   *
+   * The %_Executor class has two modes: DFS mode and BFS mode, controlled
+   * by the template parameter %__dfs_mode.
+   */
+  template<typename _BiIter, typename _Alloc, typename _TraitsT,
+	   bool __dfs_mode>
+    class _Executor
+    {
+      using __search_mode = integral_constant<bool, __dfs_mode>;
+      using __dfs = true_type;
+      using __bfs = false_type;
+
+      enum class _Match_mode : unsigned char { _Exact, _Prefix };
+
+    public:
+      typedef typename iterator_traits<_BiIter>::value_type _CharT;
+      typedef basic_regex<_CharT, _TraitsT>                 _RegexT;
+      typedef _GLIBCXX_STD_C::vector<sub_match<_BiIter>, _Alloc> _ResultsVec;
+      typedef regex_constants::match_flag_type              _FlagT;
+      typedef typename _TraitsT::char_class_type            _ClassT;
+      typedef _NFA<_TraitsT>                                _NFAT;
+
+    public:
+      _Executor(_BiIter         __begin,
+		_BiIter         __end,
+		_ResultsVec&    __results,
+		const _RegexT&  __re,
+		_FlagT          __flags)
+      : _M_begin(__begin),
+      _M_end(__end),
+      _M_re(__re),
+      _M_nfa(*__re._M_automaton),
+      _M_results(__results),
+      _M_rep_count(_M_nfa.size()),
+      _M_states(_M_nfa._M_start(), _M_nfa.size()),
+      _M_flags(__flags)
+      {
+	using namespace regex_constants;
+	if (__flags & match_prev_avail) // ignore not_bol and not_bow
+	  _M_flags &= ~(match_not_bol | match_not_bow);
+      }
+
+      // Set matched when string exactly matches the pattern.
+      bool
+      _M_match()
+      {
+	_M_current = _M_begin;
+	return _M_main(_Match_mode::_Exact);
+      }
+
+      // Set matched when some prefix of the string matches the pattern.
+      bool
+      _M_search_from_first()
+      {
+	_M_current = _M_begin;
+	return _M_main(_Match_mode::_Prefix);
+      }
+
+      bool
+      _M_search();
+
+    private:
+      void
+      _M_rep_once_more(_Match_mode __match_mode, _StateIdT);
+
+      void
+      _M_handle_repeat(_Match_mode, _StateIdT);
+
+      void
+      _M_handle_subexpr_begin(_Match_mode, _StateIdT);
+
+      void
+      _M_handle_subexpr_end(_Match_mode, _StateIdT);
+
+      void
+      _M_handle_line_begin_assertion(_Match_mode, _StateIdT);
+
+      void
+      _M_handle_line_end_assertion(_Match_mode, _StateIdT);
+
+      void
+      _M_handle_word_boundary(_Match_mode, _StateIdT);
+
+      void
+      _M_handle_subexpr_lookahead(_Match_mode, _StateIdT);
+
+      void
+      _M_handle_match(_Match_mode, _StateIdT);
+
+      void
+      _M_handle_backref(_Match_mode, _StateIdT);
+
+      void
+      _M_handle_accept(_Match_mode, _StateIdT);
+
+      void
+      _M_handle_alternative(_Match_mode, _StateIdT);
+
+      void
+      _M_dfs(_Match_mode __match_mode, _StateIdT __start);
+
+      bool
+      _M_main(_Match_mode __match_mode)
+      { return _M_main_dispatch(__match_mode, __search_mode{}); }
+
+      bool
+      _M_main_dispatch(_Match_mode __match_mode, __dfs);
+
+      bool
+      _M_main_dispatch(_Match_mode __match_mode, __bfs);
+
+      bool
+      _M_is_word(_CharT __ch) const
+      {
+	static const _CharT __s[2] = { 'w' };
+	return _M_re._M_automaton->_M_traits.isctype
+	  (__ch, _M_re._M_automaton->_M_traits.lookup_classname(__s, __s+1));
+      }
+
+      bool
+      _M_at_begin() const
+      {
+	if (_M_current == _M_begin)
+	  {
+	    // match_not_bol means ^ does not match [_M_begin,_M_begin)
+	    if (_M_flags & regex_constants::match_not_bol)
+	      return false;
+	    // match_prev_avail means _M_begin is not the start of the input.
+	    if (_M_flags & regex_constants::match_prev_avail)
+	      {
+		// For ECMAScript multiline matches, check if the previous
+		// character is a line terminator.
+		if (_M_match_multiline())
+		  return _M_is_line_terminator(*std::prev(_M_current));
+		else
+		  return false;
+	      }
+	    else // ^ matches at _M_begin
+	      return true;
+	  }
+	else if (_M_match_multiline())
+	  return _M_is_line_terminator(*std::prev(_M_current));
+	else
+	  return false;
+      }
+
+      bool
+      _M_at_end() const
+      {
+	if (_M_current == _M_end)
+	  return !(_M_flags & regex_constants::match_not_eol);
+	else if (_M_match_multiline())
+	  return _M_is_line_terminator(*_M_current);
+	else
+	  return false;
+      }
+
+      bool
+      _M_word_boundary() const;
+
+      bool
+      _M_lookahead(_StateIdT __next);
+
+      bool
+      _M_is_line_terminator(_CharT __c) const
+      {
+	const auto& __traits = _M_re._M_automaton->_M_traits;
+	const auto& __ct = use_facet<ctype<_CharT>>(__traits.getloc());
+	const char __n{ __ct.narrow(__c, ' ') };
+	if (__n == '\n')
+	  return true;
+	if (_M_re._M_automaton->_M_options() & regex_constants::ECMAScript)
+	  {
+	    if (__n == '\r')
+	      return true;
+	    // FIXME: U+2028 (line separator) and U+2029 (paragraph separator)
+	  }
+	return false;
+      }
+
+      bool
+      _M_match_multiline() const noexcept
+      {
+	constexpr auto __m
+	  = regex_constants::ECMAScript | regex_constants::__multiline;
+	return (_M_re._M_automaton->_M_options() & __m) == __m;
+      }
+
+       // Holds additional information used in BFS-mode.
+      template<typename _SearchMode, typename _ResultsVec>
+	struct _State_info;
+
+      template<typename _ResultsVec>
+	struct _State_info<__bfs, _ResultsVec>
+	{
+	  explicit
+	  _State_info(_StateIdT __start, size_t __n)
+	  : _M_visited_states(new bool[__n]()), _M_start(__start)
+	  { }
+
+	  ~_State_info() { delete[] _M_visited_states; }
+
+	  _State_info(const _State_info&) = delete;
+	  _State_info& operator=(const _State_info&) = delete;
+
+	  bool _M_visited(_StateIdT __i)
+	  {
+	    if (_M_visited_states[__i])
+	      return true;
+	    _M_visited_states[__i] = true;
+	    return false;
+	  }
+
+	  void _M_queue(_StateIdT __i, const _ResultsVec& __res)
+	  { _M_match_queue.emplace_back(__i, __res); }
+
+	  // Dummy implementations for BFS mode.
+	  _BiIter* _M_get_sol_pos() { return nullptr; }
+
+	  // Saves states that need to be considered for the next character.
+	  _GLIBCXX_STD_C::vector<pair<_StateIdT, _ResultsVec>> _M_match_queue;
+	  // Indicates which states are already visited.
+	  bool*     _M_visited_states;
+	  // To record current solution.
+	  _StateIdT _M_start;
+	};
+
+      template<typename _ResultsVec>
+	struct _State_info<__dfs, _ResultsVec>
+	{
+	  explicit
+	  _State_info(_StateIdT __start, size_t) : _M_start(__start)
+	  { }
+
+	  // Dummy implementations for DFS mode.
+	  bool _M_visited(_StateIdT) const { return false; }
+	  void _M_queue(_StateIdT, const _ResultsVec&) { }
+
+	  _BiIter* _M_get_sol_pos() { return &_M_sol_pos; }
+
+	  // To record current solution.
+	  _StateIdT _M_start;
+	  _BiIter   _M_sol_pos;
+	};
+
+    public:
+      _ResultsVec                                           _M_cur_results;
+      _BiIter                                               _M_current;
+      _BiIter                                               _M_begin;
+      const _BiIter                                         _M_end;
+      const _RegexT&                                        _M_re;
+      const _NFAT&                                          _M_nfa;
+      _ResultsVec&                                          _M_results;
+      _GLIBCXX_STD_C::vector<pair<_BiIter, int>>            _M_rep_count;
+      _State_info<__search_mode, _ResultsVec>		    _M_states;
+      _FlagT                                                _M_flags;
+      // Do we have a solution so far?
+      bool                                                  _M_has_sol;
+    };
+
+ ///@} regex-detail
+} // namespace __detail
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#include <bits/regex_executor.tcc>
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@regex_executor.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@regex_executor.h.blob
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@@ -0,0 +1,568 @@
+// class template regex -*- C++ -*-
+
+// Copyright (C) 2013-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/**
+ *  @file bits/regex_executor.tcc
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{regex}
+ */
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+namespace __detail
+{
+  template<typename _BiIter, typename _Alloc, typename _TraitsT,
+	   bool __dfs_mode>
+    bool _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>::
+    _M_search()
+    {
+      if (_M_search_from_first())
+	return true;
+      if (_M_flags & regex_constants::match_continuous)
+	return false;
+      _M_flags |= regex_constants::match_prev_avail;
+      while (_M_begin != _M_end)
+	{
+	  ++_M_begin;
+	  if (_M_search_from_first())
+	    return true;
+	}
+      return false;
+    }
+
+  // The _M_main function operates in different modes, DFS mode or BFS mode,
+  // indicated by template parameter __dfs_mode, and dispatches to one of the
+  // _M_main_dispatch overloads.
+  //
+  // ------------------------------------------------------------
+  //
+  // DFS mode:
+  //
+  // It applies a Depth-First-Search (aka backtracking) on given NFA and input
+  // string.
+  // At the very beginning the executor stands in the start state, then it
+  // tries every possible state transition in current state recursively. Some
+  // state transitions consume input string, say, a single-char-matcher or a
+  // back-reference matcher; some don't, like assertion or other anchor nodes.
+  // When the input is exhausted and/or the current state is an accepting
+  // state, the whole executor returns true.
+  //
+  // TODO: This approach is exponentially slow for certain input.
+  //       Try to compile the NFA to a DFA.
+  //
+  // Time complexity: \Omega(match_length), O(2^(_M_nfa.size()))
+  // Space complexity: \theta(match_results.size() + match_length)
+  //
+  template<typename _BiIter, typename _Alloc, typename _TraitsT,
+	   bool __dfs_mode>
+    bool _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>::
+    _M_main_dispatch(_Match_mode __match_mode, __dfs)
+    {
+      _M_has_sol = false;
+      *_M_states._M_get_sol_pos() = _BiIter();
+      _M_cur_results = _M_results;
+      _M_dfs(__match_mode, _M_states._M_start);
+      return _M_has_sol;
+    }
+
+  // ------------------------------------------------------------
+  //
+  // BFS mode:
+  //
+  // Russ Cox's article (http://swtch.com/~rsc/regexp/regexp1.html)
+  // explained this algorithm clearly.
+  //
+  // It first computes epsilon closure (states that can be achieved without
+  // consuming characters) for every state that's still matching,
+  // using the same DFS algorithm, but doesn't re-enter states (using
+  // _M_states._M_visited to check), nor follow _S_opcode_match.
+  //
+  // Then apply DFS using every _S_opcode_match (in _M_states._M_match_queue)
+  // as the start state.
+  //
+  // It significantly reduces potential duplicate states, so has a better
+  // upper bound; but it requires more overhead.
+  //
+  // Time complexity: \Omega(match_length * match_results.size())
+  //                  O(match_length * _M_nfa.size() * match_results.size())
+  // Space complexity: \Omega(_M_nfa.size() + match_results.size())
+  //                   O(_M_nfa.size() * match_results.size())
+  template<typename _BiIter, typename _Alloc, typename _TraitsT,
+	   bool __dfs_mode>
+    bool _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>::
+    _M_main_dispatch(_Match_mode __match_mode, __bfs)
+    {
+      _M_states._M_queue(_M_states._M_start, _M_results);
+      bool __ret = false;
+      while (1)
+	{
+	  _M_has_sol = false;
+	  if (_M_states._M_match_queue.empty())
+	    break;
+	  std::fill_n(_M_states._M_visited_states, _M_nfa.size(), false);
+	  auto __old_queue = std::move(_M_states._M_match_queue);
+	  for (auto& __task : __old_queue)
+	    {
+	      _M_cur_results = std::move(__task.second);
+	      _M_dfs(__match_mode, __task.first);
+	    }
+	  if (__match_mode == _Match_mode::_Prefix)
+	    __ret |= _M_has_sol;
+	  if (_M_current == _M_end)
+	    break;
+	  ++_M_current;
+	}
+      if (__match_mode == _Match_mode::_Exact)
+	__ret = _M_has_sol;
+      _M_states._M_match_queue.clear();
+      return __ret;
+    }
+
+  // Return whether now match the given sub-NFA.
+  template<typename _BiIter, typename _Alloc, typename _TraitsT,
+	   bool __dfs_mode>
+    bool _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>::
+    _M_lookahead(_StateIdT __next)
+    {
+      // Backreferences may refer to captured content.
+      // We may want to make this faster by not copying,
+      // but let's not be clever prematurely.
+      _ResultsVec __what(_M_cur_results);
+      _Executor __sub(_M_current, _M_end, __what, _M_re, _M_flags);
+      __sub._M_states._M_start = __next;
+      if (__sub._M_search_from_first())
+	{
+	  for (size_t __i = 0; __i < __what.size(); __i++)
+	    if (__what[__i].matched)
+	      _M_cur_results[__i] = __what[__i];
+	  return true;
+	}
+      return false;
+    }
+
+  // __rep_count records how many times (__rep_count.second)
+  // this node is visited under certain input iterator
+  // (__rep_count.first). This prevent the executor from entering
+  // infinite loop by refusing to continue when it's already been
+  // visited more than twice. It's `twice` instead of `once` because
+  // we need to spare one more time for potential group capture.
+  template<typename _BiIter, typename _Alloc, typename _TraitsT,
+	   bool __dfs_mode>
+    void _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>::
+    _M_rep_once_more(_Match_mode __match_mode, _StateIdT __i)
+    {
+      const auto& __state = _M_nfa[__i];
+      auto& __rep_count = _M_rep_count[__i];
+      if (__rep_count.second == 0 || __rep_count.first != _M_current)
+	{
+	  auto __back = __rep_count;
+	  __rep_count.first = _M_current;
+	  __rep_count.second = 1;
+	  _M_dfs(__match_mode, __state._M_alt);
+	  __rep_count = __back;
+	}
+      else
+	{
+	  if (__rep_count.second < 2)
+	    {
+	      __rep_count.second++;
+	      _M_dfs(__match_mode, __state._M_alt);
+	      __rep_count.second--;
+	    }
+	}
+    }
+
+  // _M_alt branch is "match once more", while _M_next is "get me out
+  // of this quantifier". Executing _M_next first or _M_alt first don't
+  // mean the same thing, and we need to choose the correct order under
+  // given greedy mode.
+  template<typename _BiIter, typename _Alloc, typename _TraitsT,
+	   bool __dfs_mode>
+    void _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>::
+    _M_handle_repeat(_Match_mode __match_mode, _StateIdT __i)
+    {
+      const auto& __state = _M_nfa[__i];
+
+      // Greedy.
+      if (!__state._M_neg)
+	{
+	  _M_rep_once_more(__match_mode, __i);
+	  // If it's DFS executor and already accepted, we're done.
+	  if (!__dfs_mode || !_M_has_sol)
+	    _M_dfs(__match_mode, __state._M_next);
+	}
+      else // Non-greedy mode
+	{
+	  if (__dfs_mode)
+	    {
+	      // vice-versa.
+	      _M_dfs(__match_mode, __state._M_next);
+	      if (!_M_has_sol)
+		_M_rep_once_more(__match_mode, __i);
+	    }
+	  else
+	    {
+	      // DON'T attempt anything, because there's already another
+	      // state with higher priority accepted. This state cannot
+	      // be better by attempting its next node.
+	      if (!_M_has_sol)
+		{
+		  _M_dfs(__match_mode, __state._M_next);
+		  // DON'T attempt anything if it's already accepted. An
+		  // accepted state *must* be better than a solution that
+		  // matches a non-greedy quantifier one more time.
+		  if (!_M_has_sol)
+		    _M_rep_once_more(__match_mode, __i);
+		}
+	    }
+	}
+    }
+
+  template<typename _BiIter, typename _Alloc, typename _TraitsT,
+	   bool __dfs_mode>
+    void _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>::
+    _M_handle_subexpr_begin(_Match_mode __match_mode, _StateIdT __i)
+    {
+      const auto& __state = _M_nfa[__i];
+
+      auto& __res = _M_cur_results[__state._M_subexpr];
+      auto __back = __res.first;
+      __res.first = _M_current;
+      _M_dfs(__match_mode, __state._M_next);
+      __res.first = __back;
+    }
+
+  template<typename _BiIter, typename _Alloc, typename _TraitsT,
+	   bool __dfs_mode>
+    void _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>::
+    _M_handle_subexpr_end(_Match_mode __match_mode, _StateIdT __i)
+    {
+      const auto& __state = _M_nfa[__i];
+
+      auto& __res = _M_cur_results[__state._M_subexpr];
+      auto __back = __res;
+      __res.second = _M_current;
+      __res.matched = true;
+      _M_dfs(__match_mode, __state._M_next);
+      __res = __back;
+    }
+
+  template<typename _BiIter, typename _Alloc, typename _TraitsT,
+	   bool __dfs_mode>
+    inline void _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>::
+    _M_handle_line_begin_assertion(_Match_mode __match_mode, _StateIdT __i)
+    {
+      const auto& __state = _M_nfa[__i];
+      if (_M_at_begin())
+	_M_dfs(__match_mode, __state._M_next);
+    }
+
+  template<typename _BiIter, typename _Alloc, typename _TraitsT,
+	   bool __dfs_mode>
+    inline void _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>::
+    _M_handle_line_end_assertion(_Match_mode __match_mode, _StateIdT __i)
+    {
+      const auto& __state = _M_nfa[__i];
+      if (_M_at_end())
+	_M_dfs(__match_mode, __state._M_next);
+    }
+
+  template<typename _BiIter, typename _Alloc, typename _TraitsT,
+	   bool __dfs_mode>
+    inline void _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>::
+    _M_handle_word_boundary(_Match_mode __match_mode, _StateIdT __i)
+    {
+      const auto& __state = _M_nfa[__i];
+      if (_M_word_boundary() == !__state._M_neg)
+	_M_dfs(__match_mode, __state._M_next);
+    }
+
+  // Here __state._M_alt offers a single start node for a sub-NFA.
+  // We recursively invoke our algorithm to match the sub-NFA.
+  template<typename _BiIter, typename _Alloc, typename _TraitsT,
+	   bool __dfs_mode>
+    void _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>::
+    _M_handle_subexpr_lookahead(_Match_mode __match_mode, _StateIdT __i)
+    {
+      const auto& __state = _M_nfa[__i];
+      if (_M_lookahead(__state._M_alt) == !__state._M_neg)
+	_M_dfs(__match_mode, __state._M_next);
+    }
+
+  template<typename _BiIter, typename _Alloc, typename _TraitsT,
+	   bool __dfs_mode>
+    void _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>::
+    _M_handle_match(_Match_mode __match_mode, _StateIdT __i)
+    {
+      const auto& __state = _M_nfa[__i];
+
+      if (_M_current == _M_end)
+	return;
+      if (__dfs_mode)
+	{
+	  if (__state._M_matches(*_M_current))
+	    {
+	      ++_M_current;
+	      _M_dfs(__match_mode, __state._M_next);
+	      --_M_current;
+	    }
+	}
+      else
+	if (__state._M_matches(*_M_current))
+	  _M_states._M_queue(__state._M_next, _M_cur_results);
+    }
+
+  template<typename _BiIter, typename _TraitsT>
+    struct _Backref_matcher
+    {
+      _Backref_matcher(bool __icase, const _TraitsT& __traits)
+      : _M_traits(__traits) { }
+
+      bool
+      _M_apply(_BiIter __expected_begin,
+	       _BiIter __expected_end, _BiIter __actual_begin,
+	       _BiIter __actual_end)
+      {
+	return _M_traits.transform(__expected_begin, __expected_end)
+	    == _M_traits.transform(__actual_begin, __actual_end);
+      }
+
+      const _TraitsT& _M_traits;
+    };
+
+  template<typename _BiIter, typename _CharT>
+    struct _Backref_matcher<_BiIter, std::regex_traits<_CharT>>
+    {
+      using _TraitsT = std::regex_traits<_CharT>;
+      _Backref_matcher(bool __icase, const _TraitsT& __traits)
+      : _M_icase(__icase), _M_traits(__traits) { }
+
+      bool
+      _M_apply(_BiIter __expected_begin,
+	       _BiIter __expected_end, _BiIter __actual_begin,
+	       _BiIter __actual_end)
+      {
+	if (!_M_icase)
+	  return _GLIBCXX_STD_A::__equal4(__expected_begin, __expected_end,
+			       __actual_begin, __actual_end);
+	typedef std::ctype<_CharT> __ctype_type;
+	const auto& __fctyp = use_facet<__ctype_type>(_M_traits.getloc());
+	return _GLIBCXX_STD_A::__equal4(__expected_begin, __expected_end,
+			     __actual_begin, __actual_end,
+			     [this, &__fctyp](_CharT __lhs, _CharT __rhs)
+			     {
+			       return __fctyp.tolower(__lhs)
+				 == __fctyp.tolower(__rhs);
+			     });
+      }
+
+      bool _M_icase;
+      const _TraitsT& _M_traits;
+    };
+
+  // First fetch the matched result from _M_cur_results as __submatch;
+  // then compare it with
+  // (_M_current, _M_current + (__submatch.second - __submatch.first)).
+  // If matched, keep going; else just return and try another state.
+  template<typename _BiIter, typename _Alloc, typename _TraitsT,
+	   bool __dfs_mode>
+    void _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>::
+    _M_handle_backref(_Match_mode __match_mode, _StateIdT __i)
+    {
+      __glibcxx_assert(__dfs_mode);
+
+      const auto& __state = _M_nfa[__i];
+      auto& __submatch = _M_cur_results[__state._M_backref_index];
+      if (!__submatch.matched)
+	return;
+      auto __last = _M_current;
+      for (auto __tmp = __submatch.first;
+	   __last != _M_end && __tmp != __submatch.second;
+	   ++__tmp)
+	++__last;
+      if (_Backref_matcher<_BiIter, _TraitsT>(
+	      _M_re.flags() & regex_constants::icase,
+	      _M_re._M_automaton->_M_traits)._M_apply(
+		  __submatch.first, __submatch.second, _M_current, __last))
+	{
+	  if (__last != _M_current)
+	    {
+	      auto __backup = _M_current;
+	      _M_current = __last;
+	      _M_dfs(__match_mode, __state._M_next);
+	      _M_current = __backup;
+	    }
+	  else
+	    _M_dfs(__match_mode, __state._M_next);
+	}
+    }
+
+  template<typename _BiIter, typename _Alloc, typename _TraitsT,
+	   bool __dfs_mode>
+    void _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>::
+    _M_handle_accept(_Match_mode __match_mode, _StateIdT)
+    {
+      if _GLIBCXX17_CONSTEXPR (__dfs_mode)
+	{
+	  __glibcxx_assert(!_M_has_sol);
+	  if (__match_mode == _Match_mode::_Exact)
+	    _M_has_sol = _M_current == _M_end;
+	  else
+	    _M_has_sol = true;
+	  if (_M_current == _M_begin
+	      && (_M_flags & regex_constants::match_not_null))
+	    _M_has_sol = false;
+	  if (_M_has_sol)
+	    {
+	      if (_M_nfa._M_flags & regex_constants::ECMAScript)
+		_M_results = _M_cur_results;
+	      else // POSIX
+		{
+		  __glibcxx_assert(_M_states._M_get_sol_pos());
+		  // Here's POSIX's logic: match the longest one. However
+		  // we never know which one (lhs or rhs of "|") is longer
+		  // unless we try both of them and compare the results.
+		  // The member variable _M_sol_pos records the end
+		  // position of the last successful match. It's better
+		  // to be larger, because POSIX regex is always greedy.
+		  // TODO: This could be slow.
+		  if (*_M_states._M_get_sol_pos() == _BiIter()
+		      || std::distance(_M_begin,
+				       *_M_states._M_get_sol_pos())
+			 < std::distance(_M_begin, _M_current))
+		    {
+		      *_M_states._M_get_sol_pos() = _M_current;
+		      _M_results = _M_cur_results;
+		    }
+		}
+	    }
+	}
+      else
+	{
+	  if (_M_current == _M_begin
+	      && (_M_flags & regex_constants::match_not_null))
+	    return;
+	  if (__match_mode == _Match_mode::_Prefix || _M_current == _M_end)
+	    if (!_M_has_sol)
+	      {
+		_M_has_sol = true;
+		_M_results = _M_cur_results;
+	      }
+	}
+    }
+
+  template<typename _BiIter, typename _Alloc, typename _TraitsT,
+	   bool __dfs_mode>
+    void _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>::
+    _M_handle_alternative(_Match_mode __match_mode, _StateIdT __i)
+    {
+      const auto& __state = _M_nfa[__i];
+
+      if (_M_nfa._M_flags & regex_constants::ECMAScript)
+	{
+	  // TODO: Fix BFS support. It is wrong.
+	  _M_dfs(__match_mode, __state._M_alt);
+	  // Pick lhs if it matches. Only try rhs if it doesn't.
+	  if (!_M_has_sol)
+	    _M_dfs(__match_mode, __state._M_next);
+	}
+      else
+	{
+	  // Try both and compare the result.
+	  // See "case _S_opcode_accept:" handling above.
+	  _M_dfs(__match_mode, __state._M_alt);
+	  auto __has_sol = _M_has_sol;
+	  _M_has_sol = false;
+	  _M_dfs(__match_mode, __state._M_next);
+	  _M_has_sol |= __has_sol;
+	}
+    }
+
+  template<typename _BiIter, typename _Alloc, typename _TraitsT,
+	   bool __dfs_mode>
+    void _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>::
+    _M_dfs(_Match_mode __match_mode, _StateIdT __i)
+    {
+      if (_M_states._M_visited(__i))
+	return;
+
+      switch (_M_nfa[__i]._M_opcode())
+	{
+	case _S_opcode_repeat:
+	  _M_handle_repeat(__match_mode, __i); break;
+	case _S_opcode_subexpr_begin:
+	  _M_handle_subexpr_begin(__match_mode, __i); break;
+	case _S_opcode_subexpr_end:
+	  _M_handle_subexpr_end(__match_mode, __i); break;
+	case _S_opcode_line_begin_assertion:
+	  _M_handle_line_begin_assertion(__match_mode, __i); break;
+	case _S_opcode_line_end_assertion:
+	  _M_handle_line_end_assertion(__match_mode, __i); break;
+	case _S_opcode_word_boundary:
+	  _M_handle_word_boundary(__match_mode, __i); break;
+	case _S_opcode_subexpr_lookahead:
+	  _M_handle_subexpr_lookahead(__match_mode, __i); break;
+	case _S_opcode_match:
+	  _M_handle_match(__match_mode, __i); break;
+	case _S_opcode_backref:
+	  _M_handle_backref(__match_mode, __i); break;
+	case _S_opcode_accept:
+	  _M_handle_accept(__match_mode, __i); break;
+	case _S_opcode_alternative:
+	  _M_handle_alternative(__match_mode, __i); break;
+	default:
+	  __glibcxx_assert(false);
+	}
+    }
+
+  // Return whether now is at some word boundary.
+  template<typename _BiIter, typename _Alloc, typename _TraitsT,
+	   bool __dfs_mode>
+    bool _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>::
+    _M_word_boundary() const
+    {
+      if (_M_current == _M_begin && (_M_flags & regex_constants::match_not_bow))
+	return false;
+      if (_M_current == _M_end && (_M_flags & regex_constants::match_not_eow))
+	return false;
+
+      bool __left_is_word = false;
+      if (_M_current != _M_begin
+	  || (_M_flags & regex_constants::match_prev_avail))
+	{
+	  auto __prev = _M_current;
+	  if (_M_is_word(*std::prev(__prev)))
+	    __left_is_word = true;
+	}
+      bool __right_is_word =
+        _M_current != _M_end && _M_is_word(*_M_current);
+
+      return __left_is_word != __right_is_word;
+    }
+} // namespace __detail
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@regex_executor.tcc.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@regex_executor.tcc.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@regex_scanner.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@regex_scanner.h
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@regex_scanner.h
@@ -0,0 +1,271 @@
+// class template regex -*- C++ -*-
+
+// Copyright (C) 2013-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/**
+ *  @file bits/regex_scanner.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{regex}
+ */
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+namespace __detail
+{
+  /**
+   * @addtogroup regex-detail
+   * @{
+   */
+
+  struct _ScannerBase
+  {
+  public:
+    /// Token types returned from the scanner.
+    enum _TokenT : unsigned
+    {
+      _S_token_anychar,
+      _S_token_ord_char,
+      _S_token_oct_num,
+      _S_token_hex_num,
+      _S_token_backref,
+      _S_token_subexpr_begin,
+      _S_token_subexpr_no_group_begin,
+      _S_token_subexpr_lookahead_begin, // neg if _M_value[0] == 'n'
+      _S_token_subexpr_end,
+      _S_token_bracket_begin,
+      _S_token_bracket_neg_begin,
+      _S_token_bracket_end,
+      _S_token_interval_begin,
+      _S_token_interval_end,
+      _S_token_quoted_class,
+      _S_token_char_class_name,
+      _S_token_collsymbol,
+      _S_token_equiv_class_name,
+      _S_token_opt,
+      _S_token_or,
+      _S_token_closure0,
+      _S_token_closure1,
+      _S_token_line_begin,
+      _S_token_line_end,
+      _S_token_word_bound, // neg if _M_value[0] == 'n'
+      _S_token_comma,
+      _S_token_dup_count,
+      _S_token_eof,
+      _S_token_bracket_dash,
+      _S_token_unknown = -1u
+    };
+
+  protected:
+    typedef regex_constants::syntax_option_type _FlagT;
+
+    enum _StateT
+    {
+      _S_state_normal,
+      _S_state_in_brace,
+      _S_state_in_bracket,
+    };
+
+  protected:
+    _ScannerBase(_FlagT __flags)
+    : _M_state(_S_state_normal),
+    _M_flags(__flags),
+    _M_escape_tbl(_M_is_ecma()
+		  ? _M_ecma_escape_tbl
+		  : _M_awk_escape_tbl),
+    _M_spec_char(_M_is_ecma()
+		 ? _M_ecma_spec_char
+		 : _M_flags & regex_constants::basic
+		 ? _M_basic_spec_char
+		 : _M_flags & regex_constants::extended
+		 ? _M_extended_spec_char
+		 : _M_flags & regex_constants::grep
+		 ?  ".[\\*^$\n"
+		 : _M_flags & regex_constants::egrep
+		 ? ".[\\()*+?{|^$\n"
+		 : _M_flags & regex_constants::awk
+		 ? _M_extended_spec_char
+		 : nullptr),
+    _M_at_bracket_start(false)
+    { __glibcxx_assert(_M_spec_char); }
+
+  protected:
+    const char*
+    _M_find_escape(char __c)
+    {
+      auto __it = _M_escape_tbl;
+      for (; __it->first != '\0'; ++__it)
+	if (__it->first == __c)
+	  return &__it->second;
+      return nullptr;
+    }
+
+    bool
+    _M_is_ecma() const
+    { return _M_flags & regex_constants::ECMAScript; }
+
+    bool
+    _M_is_basic() const
+    { return _M_flags & (regex_constants::basic | regex_constants::grep); }
+
+    bool
+    _M_is_extended() const
+    {
+      return _M_flags & (regex_constants::extended
+			 | regex_constants::egrep
+			 | regex_constants::awk);
+    }
+
+    bool
+    _M_is_grep() const
+    { return _M_flags & (regex_constants::grep | regex_constants::egrep); }
+
+    bool
+    _M_is_awk() const
+    { return _M_flags & regex_constants::awk; }
+
+  protected:
+    // TODO: Make them static in the next abi change.
+    const std::pair<char, _TokenT> _M_token_tbl[9] =
+      {
+	{'^', _S_token_line_begin},
+	{'$', _S_token_line_end},
+	{'.', _S_token_anychar},
+	{'*', _S_token_closure0},
+	{'+', _S_token_closure1},
+	{'?', _S_token_opt},
+	{'|', _S_token_or},
+	{'\n', _S_token_or}, // grep and egrep
+	{'\0', _S_token_or},
+      };
+    const std::pair<char, char> _M_ecma_escape_tbl[8] =
+      {
+	{'0', '\0'},
+	{'b', '\b'},
+	{'f', '\f'},
+	{'n', '\n'},
+	{'r', '\r'},
+	{'t', '\t'},
+	{'v', '\v'},
+	{'\0', '\0'},
+      };
+    const std::pair<char, char> _M_awk_escape_tbl[11] =
+      {
+	{'"', '"'},
+	{'/', '/'},
+	{'\\', '\\'},
+	{'a', '\a'},
+	{'b', '\b'},
+	{'f', '\f'},
+	{'n', '\n'},
+	{'r', '\r'},
+	{'t', '\t'},
+	{'v', '\v'},
+	{'\0', '\0'},
+      };
+    const char* _M_ecma_spec_char = "^$\\.*+?()[]{}|";
+    const char* _M_basic_spec_char = ".[\\*^$";
+    const char* _M_extended_spec_char = ".[\\()*+?{|^$";
+
+    _StateT                       _M_state;
+    _FlagT                        _M_flags;
+    _TokenT                       _M_token;
+    const std::pair<char, char>*  _M_escape_tbl;
+    const char*                   _M_spec_char;
+    bool                          _M_at_bracket_start;
+  };
+
+  /**
+   * @brief Scans an input range for regex tokens.
+   *
+   * The %_Scanner class interprets the regular expression pattern in
+   * the input range passed to its constructor as a sequence of parse
+   * tokens passed to the regular expression compiler.  The sequence
+   * of tokens provided depends on the flag settings passed to the
+   * constructor: different regular expression grammars will interpret
+   * the same input pattern in syntactically different ways.
+   */
+  template<typename _CharT>
+    class _Scanner
+    : public _ScannerBase
+    {
+    public:
+      typedef std::basic_string<_CharT>                           _StringT;
+      typedef regex_constants::syntax_option_type                 _FlagT;
+      typedef const std::ctype<_CharT>                            _CtypeT;
+
+      _Scanner(const _CharT* __begin, const _CharT* __end,
+	       _FlagT __flags, std::locale __loc);
+
+      void
+      _M_advance();
+
+      _TokenT
+      _M_get_token() const noexcept
+      { return _M_token; }
+
+      const _StringT&
+      _M_get_value() const noexcept
+      { return _M_value; }
+
+#ifdef _GLIBCXX_DEBUG
+      std::ostream&
+      _M_print(std::ostream&);
+#endif
+
+    private:
+      void
+      _M_scan_normal();
+
+      void
+      _M_scan_in_bracket();
+
+      void
+      _M_scan_in_brace();
+
+      void
+      _M_eat_escape_ecma();
+
+      void
+      _M_eat_escape_posix();
+
+      void
+      _M_eat_escape_awk();
+
+      void
+      _M_eat_class(char);
+
+      const _CharT*                 _M_current;
+      const _CharT*                 _M_end;
+      _CtypeT&                      _M_ctype;
+      _StringT                      _M_value;
+      void (_Scanner::* _M_eat_escape)();
+    };
+
+ ///@} regex-detail
+} // namespace __detail
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#include <bits/regex_scanner.tcc>
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@@ -0,0 +1,584 @@
+// class template regex -*- C++ -*-
+
+// Copyright (C) 2013-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/**
+ *  @file bits/regex_scanner.tcc
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{regex}
+ */
+
+// FIXME make comments doxygen format.
+
+// N3376 specified 6 regex styles: ECMAScript, basic, extended, grep, egrep
+// and awk
+// 1) grep is basic except '\n' is treated as '|'
+// 2) egrep is extended except '\n' is treated as '|'
+// 3) awk is extended except special escaping rules, and there's no
+//    back-reference.
+//
+// References:
+//
+// ECMAScript: ECMA-262 15.10
+//
+// basic, extended:
+// http://pubs.opengroup.org/onlinepubs/009695399/basedefs/xbd_chap09.html
+//
+// awk: http://pubs.opengroup.org/onlinepubs/000095399/utilities/awk.html
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+namespace __detail
+{
+  template<typename _CharT>
+    _Scanner<_CharT>::
+    _Scanner(const _CharT* __begin, const _CharT* __end,
+	     _FlagT __flags, std::locale __loc)
+    : _ScannerBase(__flags),
+      _M_current(__begin), _M_end(__end),
+      _M_ctype(std::use_facet<_CtypeT>(__loc)),
+      _M_eat_escape(_M_is_ecma()
+		    ? &_Scanner::_M_eat_escape_ecma
+		    : &_Scanner::_M_eat_escape_posix)
+    { _M_advance(); }
+
+  template<typename _CharT>
+    void
+    _Scanner<_CharT>::
+    _M_advance()
+    {
+      if (_M_current == _M_end)
+	{
+	  _M_token = _S_token_eof;
+	  return;
+	}
+
+      if (_M_state == _S_state_normal)
+	_M_scan_normal();
+      else if (_M_state == _S_state_in_bracket)
+	_M_scan_in_bracket();
+      else if (_M_state == _S_state_in_brace)
+	_M_scan_in_brace();
+      else
+	{
+	  __glibcxx_assert(!"unexpected state while processing regex");
+	}
+    }
+
+  // Differences between styles:
+  // 1) "\(", "\)", "\{" in basic. It's not escaping.
+  // 2) "(?:", "(?=", "(?!" in ECMAScript.
+  template<typename _CharT>
+    void
+    _Scanner<_CharT>::
+    _M_scan_normal()
+    {
+      auto __c = *_M_current++;
+
+      if (__builtin_strchr(_M_spec_char, _M_ctype.narrow(__c, ' ')) == nullptr)
+	{
+	  _M_token = _S_token_ord_char;
+	  _M_value.assign(1, __c);
+	  return;
+	}
+      if (__c == '\\')
+	{
+	  if (_M_current == _M_end)
+	    __throw_regex_error(
+	      regex_constants::error_escape,
+	      "Invalid escape at end of regular expression");
+
+	  if (!_M_is_basic()
+	      || (*_M_current != '('
+		  && *_M_current != ')'
+		  && *_M_current != '{'))
+	    {
+	      (this->*_M_eat_escape)();
+	      return;
+	    }
+	  __c = *_M_current++;
+	}
+      if (__c == '(')
+	{
+	  if (_M_is_ecma() && *_M_current == '?')
+	    {
+	      if (++_M_current == _M_end)
+		__throw_regex_error(regex_constants::error_paren);
+
+	      if (*_M_current == ':')
+		{
+		  ++_M_current;
+		  _M_token = _S_token_subexpr_no_group_begin;
+		}
+	      else if (*_M_current == '=')
+		{
+		  ++_M_current;
+		  _M_token = _S_token_subexpr_lookahead_begin;
+		  _M_value.assign(1, 'p');
+		}
+	      else if (*_M_current == '!')
+		{
+		  ++_M_current;
+		  _M_token = _S_token_subexpr_lookahead_begin;
+		  _M_value.assign(1, 'n');
+		}
+	      else
+		__throw_regex_error(regex_constants::error_paren,
+				    "Invalid '(?...)' zero-width assertion "
+				    "in regular expression");
+	    }
+	  else if (_M_flags & regex_constants::nosubs)
+	    _M_token = _S_token_subexpr_no_group_begin;
+	  else
+	    _M_token = _S_token_subexpr_begin;
+	}
+      else if (__c == ')')
+	_M_token = _S_token_subexpr_end;
+      else if (__c == '[')
+	{
+	  _M_state = _S_state_in_bracket;
+	  _M_at_bracket_start = true;
+	  if (_M_current != _M_end && *_M_current == '^')
+	    {
+	      _M_token = _S_token_bracket_neg_begin;
+	      ++_M_current;
+	    }
+	  else
+	    _M_token = _S_token_bracket_begin;
+	}
+      else if (__c == '{')
+	{
+	  _M_state = _S_state_in_brace;
+	  _M_token = _S_token_interval_begin;
+	}
+      else if (__builtin_expect(__c == _CharT(0), false))
+	{
+	  if (!_M_is_ecma())
+	    __throw_regex_error(regex_constants::_S_null);
+	  _M_token = _S_token_ord_char;
+	  _M_value.assign(1, __c);
+	}
+      else if (__c != ']' && __c != '}')
+	{
+	  auto __it = _M_token_tbl;
+	  auto __narrowc = _M_ctype.narrow(__c, '\0');
+	  for (; __it->first != '\0'; ++__it)
+	    if (__it->first == __narrowc)
+	      {
+		_M_token = __it->second;
+		return;
+	      }
+	  __glibcxx_assert(!"unexpected special character in regex");
+	}
+      else
+	{
+	  _M_token = _S_token_ord_char;
+	  _M_value.assign(1, __c);
+	}
+    }
+
+  // Differences between styles:
+  // 1) different semantics of "[]" and "[^]".
+  // 2) Escaping in bracket expr.
+  template<typename _CharT>
+    void
+    _Scanner<_CharT>::
+    _M_scan_in_bracket()
+    {
+      if (_M_current == _M_end)
+	__throw_regex_error(regex_constants::error_brack);
+
+      auto __c = *_M_current++;
+
+      if (__c == '-')
+	_M_token = _S_token_bracket_dash;
+      else if (__c == '[')
+	{
+	  if (_M_current == _M_end)
+	    __throw_regex_error(regex_constants::error_brack,
+				"Incomplete '[[' character class in "
+				"regular expression");
+
+	  if (*_M_current == '.')
+	    {
+	      _M_token = _S_token_collsymbol;
+	      _M_eat_class(*_M_current++);
+	    }
+	  else if (*_M_current == ':')
+	    {
+	      _M_token = _S_token_char_class_name;
+	      _M_eat_class(*_M_current++);
+	    }
+	  else if (*_M_current == '=')
+	    {
+	      _M_token = _S_token_equiv_class_name;
+	      _M_eat_class(*_M_current++);
+	    }
+	  else
+	    {
+	      _M_token = _S_token_ord_char;
+	      _M_value.assign(1, __c);
+	    }
+	}
+      // In POSIX, when encountering "[]" or "[^]", the ']' is interpreted
+      // literally. So "[]]" and "[^]]" are valid regexes. See the testcases
+      // `.../empty_range.cc`.
+      else if (__c == ']' && (_M_is_ecma() || !_M_at_bracket_start))
+	{
+	  _M_token = _S_token_bracket_end;
+	  _M_state = _S_state_normal;
+	}
+      // ECMAScript and awk permits escaping in bracket.
+      else if (__c == '\\' && (_M_is_ecma() || _M_is_awk()))
+	(this->*_M_eat_escape)();
+      else
+	{
+	  _M_token = _S_token_ord_char;
+	  _M_value.assign(1, __c);
+	}
+      _M_at_bracket_start = false;
+    }
+
+  // Differences between styles:
+  // 1) "\}" in basic style.
+  template<typename _CharT>
+    void
+    _Scanner<_CharT>::
+    _M_scan_in_brace()
+    {
+      if (_M_current == _M_end)
+	__throw_regex_error(regex_constants::error_brace);
+
+      auto __c = *_M_current++;
+
+      if (_M_ctype.is(_CtypeT::digit, __c))
+	{
+	  _M_token = _S_token_dup_count;
+	  _M_value.assign(1, __c);
+	  while (_M_current != _M_end
+		 && _M_ctype.is(_CtypeT::digit, *_M_current))
+	    _M_value += *_M_current++;
+	}
+      else if (__c == ',')
+	_M_token = _S_token_comma;
+      // basic use \}.
+      else if (_M_is_basic())
+	{
+	  if (__c == '\\' && _M_current != _M_end && *_M_current == '}')
+	    {
+	      _M_state = _S_state_normal;
+	      _M_token = _S_token_interval_end;
+	      ++_M_current;
+	    }
+	  else
+	    __throw_regex_error(regex_constants::error_badbrace);
+	}
+      else if (__c == '}')
+	{
+	  _M_state = _S_state_normal;
+	  _M_token = _S_token_interval_end;
+	}
+      else
+	__throw_regex_error(regex_constants::error_badbrace);
+    }
+
+  template<typename _CharT>
+    void
+    _Scanner<_CharT>::
+    _M_eat_escape_ecma()
+    {
+      if (_M_current == _M_end)
+	__throw_regex_error(regex_constants::error_escape);
+
+      auto __c = *_M_current++;
+      auto __pos = _M_find_escape(_M_ctype.narrow(__c, '\0'));
+
+      if (__pos != nullptr && (__c != 'b' || _M_state == _S_state_in_bracket))
+	{
+	  _M_token = _S_token_ord_char;
+	  _M_value.assign(1, *__pos);
+	}
+      else if (__c == 'b')
+	{
+	  _M_token = _S_token_word_bound;
+	  _M_value.assign(1, 'p');
+	}
+      else if (__c == 'B')
+	{
+	  _M_token = _S_token_word_bound;
+	  _M_value.assign(1, 'n');
+	}
+      // N3376 28.13
+      else if (__c == 'd'
+	       || __c == 'D'
+	       || __c == 's'
+	       || __c == 'S'
+	       || __c == 'w'
+	       || __c == 'W')
+	{
+	  _M_token = _S_token_quoted_class;
+	  _M_value.assign(1, __c);
+	}
+      else if (__c == 'c')
+	{
+	  if (_M_current == _M_end)
+	    __throw_regex_error(regex_constants::error_escape,
+				"invalid '\\cX' control character in "
+				"regular expression");
+	  _M_token = _S_token_ord_char;
+	  _M_value.assign(1, *_M_current++);
+	}
+      else if (__c == 'x' || __c == 'u')
+	{
+	  _M_value.clear();
+	  const int __n = __c == 'x' ? 2 : 4;
+	  for (int __i = 0; __i < __n; __i++)
+	    {
+	      if (_M_current == _M_end
+		  || !_M_ctype.is(_CtypeT::xdigit, *_M_current))
+		__throw_regex_error(regex_constants::error_escape,
+				    __n == 2
+				    ? "Invalid '\\xNN' control character in "
+				      "regular expression"
+				    : "Invalid '\\uNNNN' control character in "
+				      "regular expression");
+	      _M_value += *_M_current++;
+	    }
+	  _M_token = _S_token_hex_num;
+	}
+      // ECMAScript recognizes multi-digit back-references.
+      else if (_M_ctype.is(_CtypeT::digit, __c))
+	{
+	  _M_value.assign(1, __c);
+	  while (_M_current != _M_end
+		 && _M_ctype.is(_CtypeT::digit, *_M_current))
+	    _M_value += *_M_current++;
+	  _M_token = _S_token_backref;
+	}
+      else
+	{
+	  _M_token = _S_token_ord_char;
+	  _M_value.assign(1, __c);
+	}
+    }
+
+  // Differences between styles:
+  // 1) Extended doesn't support backref, but basic does.
+  template<typename _CharT>
+    void
+    _Scanner<_CharT>::
+    _M_eat_escape_posix()
+    {
+      if (_M_current == _M_end)
+	__throw_regex_error(regex_constants::error_escape);
+
+      auto __c = *_M_current;
+      auto __pos = __builtin_strchr(_M_spec_char, _M_ctype.narrow(__c, '\0'));
+
+      if (__pos != nullptr && *__pos != '\0')
+	{
+	  _M_token = _S_token_ord_char;
+	  _M_value.assign(1, __c);
+	}
+      // We MUST judge awk before handling backrefs. There's no backref in awk.
+      else if (_M_is_awk())
+	{
+	  _M_eat_escape_awk();
+	  return;
+	}
+      else if (_M_is_basic() && _M_ctype.is(_CtypeT::digit, __c) && __c != '0')
+	{
+	  _M_token = _S_token_backref;
+	  _M_value.assign(1, __c);
+	}
+      else
+	{
+#ifdef __STRICT_ANSI__
+	  // POSIX says it is undefined to escape ordinary characters
+	  __throw_regex_error(regex_constants::error_escape);
+#else
+	  _M_token = _S_token_ord_char;
+	  _M_value.assign(1, __c);
+#endif
+	}
+      ++_M_current;
+    }
+
+  template<typename _CharT>
+    void
+    _Scanner<_CharT>::
+    _M_eat_escape_awk()
+    {
+      auto __c = *_M_current++;
+      auto __pos = _M_find_escape(_M_ctype.narrow(__c, '\0'));
+
+      if (__pos != nullptr)
+	{
+	  _M_token = _S_token_ord_char;
+	  _M_value.assign(1, *__pos);
+	}
+      // \ddd for oct representation
+      else if (_M_ctype.is(_CtypeT::digit, __c)
+	       && __c != '8'
+	       && __c != '9')
+	{
+	  _M_value.assign(1,  __c);
+	  for (int __i = 0;
+	       __i < 2
+	       && _M_current != _M_end
+	       && _M_ctype.is(_CtypeT::digit, *_M_current)
+	       && *_M_current != '8'
+	       && *_M_current != '9';
+	       __i++)
+	    _M_value += *_M_current++;
+	  _M_token = _S_token_oct_num;
+	  return;
+	}
+      else
+	__throw_regex_error(regex_constants::error_escape);
+    }
+
+  // Eats a character class or throws an exception.
+  // __ch could be ':', '.' or '=', _M_current is the char after ']' when
+  // returning.
+  template<typename _CharT>
+    void
+    _Scanner<_CharT>::
+    _M_eat_class(char __ch)
+    {
+      for (_M_value.clear(); _M_current != _M_end && *_M_current != __ch;)
+	_M_value += *_M_current++;
+      if (_M_current == _M_end
+	  || *_M_current++ != __ch
+	  || _M_current == _M_end // skip __ch
+	  || *_M_current++ != ']') // skip ']'
+	{
+	  __throw_regex_error(__ch == ':' ? regex_constants::error_ctype
+					  : regex_constants::error_collate);
+	}
+    }
+
+#ifdef _GLIBCXX_DEBUG
+  template<typename _CharT>
+    std::ostream&
+    _Scanner<_CharT>::
+    _M_print(std::ostream& ostr)
+    {
+      switch (_M_token)
+      {
+      case _S_token_anychar:
+	ostr << "any-character\n";
+	break;
+      case _S_token_backref:
+	ostr << "backref\n";
+	break;
+      case _S_token_bracket_begin:
+	ostr << "bracket-begin\n";
+	break;
+      case _S_token_bracket_neg_begin:
+	ostr << "bracket-neg-begin\n";
+	break;
+      case _S_token_bracket_end:
+	ostr << "bracket-end\n";
+	break;
+      case _S_token_char_class_name:
+	ostr << "char-class-name \"" << _M_value << "\"\n";
+	break;
+      case _S_token_closure0:
+	ostr << "closure0\n";
+	break;
+      case _S_token_closure1:
+	ostr << "closure1\n";
+	break;
+      case _S_token_collsymbol:
+	ostr << "collsymbol \"" << _M_value << "\"\n";
+	break;
+      case _S_token_comma:
+	ostr << "comma\n";
+	break;
+      case _S_token_dup_count:
+	ostr << "dup count: " << _M_value << "\n";
+	break;
+      case _S_token_eof:
+	ostr << "EOF\n";
+	break;
+      case _S_token_equiv_class_name:
+	ostr << "equiv-class-name \"" << _M_value << "\"\n";
+	break;
+      case _S_token_interval_begin:
+	ostr << "interval begin\n";
+	break;
+      case _S_token_interval_end:
+	ostr << "interval end\n";
+	break;
+      case _S_token_line_begin:
+	ostr << "line begin\n";
+	break;
+      case _S_token_line_end:
+	ostr << "line end\n";
+	break;
+      case _S_token_opt:
+	ostr << "opt\n";
+	break;
+      case _S_token_or:
+	ostr << "or\n";
+	break;
+      case _S_token_ord_char:
+	ostr << "ordinary character: \"" << _M_value << "\"\n";
+	break;
+      case _S_token_subexpr_begin:
+	ostr << "subexpr begin\n";
+	break;
+      case _S_token_subexpr_no_group_begin:
+	ostr << "no grouping subexpr begin\n";
+	break;
+      case _S_token_subexpr_lookahead_begin:
+	ostr << "lookahead subexpr begin\n";
+	break;
+      case _S_token_subexpr_end:
+	ostr << "subexpr end\n";
+	break;
+      case _S_token_unknown:
+	ostr << "-- unknown token --\n";
+	break;
+      case _S_token_oct_num:
+	ostr << "oct number " << _M_value << "\n";
+	break;
+      case _S_token_hex_num:
+	ostr << "hex number " << _M_value << "\n";
+	break;
+      case _S_token_quoted_class:
+	ostr << "quoted class " << "\\" << _M_value << "\n";
+	break;
+      default:
+	_GLIBCXX_DEBUG_ASSERT(false);
+      }
+      return ostr;
+    }
+#endif
+
+} // namespace __detail
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@regex_scanner.tcc.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@regex_scanner.tcc.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@shared_ptr.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@shared_ptr.h
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@shared_ptr.h
@@ -0,0 +1,1190 @@
+// shared_ptr and weak_ptr implementation -*- C++ -*-
+
+// Copyright (C) 2007-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+// GCC Note: Based on files from version 1.32.0 of the Boost library.
+
+//  shared_count.hpp
+//  Copyright (c) 2001, 2002, 2003 Peter Dimov and Multi Media Ltd.
+
+//  shared_ptr.hpp
+//  Copyright (C) 1998, 1999 Greg Colvin and Beman Dawes.
+//  Copyright (C) 2001, 2002, 2003 Peter Dimov
+
+//  weak_ptr.hpp
+//  Copyright (C) 2001, 2002, 2003 Peter Dimov
+
+//  enable_shared_from_this.hpp
+//  Copyright (C) 2002 Peter Dimov
+
+// Distributed under the Boost Software License, Version 1.0. (See
+// accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+/** @file
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{memory}
+ */
+
+#ifndef _SHARED_PTR_H
+#define _SHARED_PTR_H 1
+
+#include <iosfwd>           	  // std::basic_ostream
+#include <bits/shared_ptr_base.h>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /**
+   * @addtogroup pointer_abstractions
+   * @{
+   */
+
+  // 20.7.2.2.11 shared_ptr I/O
+
+  /// Write the stored pointer to an ostream.
+  /// @relates shared_ptr
+  template<typename _Ch, typename _Tr, typename _Tp, _Lock_policy _Lp>
+    inline std::basic_ostream<_Ch, _Tr>&
+    operator<<(std::basic_ostream<_Ch, _Tr>& __os,
+	       const __shared_ptr<_Tp, _Lp>& __p)
+    {
+      __os << __p.get();
+      return __os;
+    }
+
+  template<typename _Del, typename _Tp, _Lock_policy _Lp>
+    inline _Del*
+    get_deleter(const __shared_ptr<_Tp, _Lp>& __p) noexcept
+    {
+#if __cpp_rtti
+      return static_cast<_Del*>(__p._M_get_deleter(typeid(_Del)));
+#else
+      return 0;
+#endif
+    }
+
+  /// 20.7.2.2.10 shared_ptr get_deleter
+
+  /// If `__p` has a deleter of type `_Del`, return a pointer to it.
+  /// @relates shared_ptr
+  template<typename _Del, typename _Tp>
+    inline _Del*
+    get_deleter(const shared_ptr<_Tp>& __p) noexcept
+    {
+#if __cpp_rtti
+      return static_cast<_Del*>(__p._M_get_deleter(typeid(_Del)));
+#else
+      return 0;
+#endif
+    }
+
+  /// @cond undocumented
+
+  // Constraint for overloads taking non-array types.
+#if __cpp_concepts && __cpp_lib_type_trait_variable_templates
+  template<typename _Tp>
+    requires (!is_array_v<_Tp>)
+    using _NonArray = _Tp;
+#else
+  template<typename _Tp>
+    using _NonArray = __enable_if_t<!is_array<_Tp>::value, _Tp>;
+#endif
+
+#if __cpp_lib_shared_ptr_arrays >= 201707L
+  // Constraint for overloads taking array types with unknown bound, U[].
+#if __cpp_concepts
+  template<typename _Tp>
+    requires is_array_v<_Tp> && (extent_v<_Tp> == 0)
+    using _UnboundedArray = _Tp;
+#else
+  template<typename _Tp>
+    using _UnboundedArray
+      = __enable_if_t<__is_array_unknown_bounds<_Tp>::value, _Tp>;
+#endif
+
+  // Constraint for overloads taking array types with known bound, U[N].
+#if __cpp_concepts
+  template<typename _Tp>
+    requires (extent_v<_Tp> != 0)
+    using _BoundedArray = _Tp;
+#else
+  template<typename _Tp>
+    using _BoundedArray
+      = __enable_if_t<__is_array_known_bounds<_Tp>::value, _Tp>;
+#endif
+
+#if __cpp_lib_smart_ptr_for_overwrite
+  // Constraint for overloads taking either non-array or bounded array, U[N].
+#if __cpp_concepts
+  template<typename _Tp>
+    requires (!is_array_v<_Tp>) || (extent_v<_Tp> != 0)
+    using _NotUnboundedArray = _Tp;
+#else
+  template<typename _Tp>
+    using _NotUnboundedArray
+      = __enable_if_t<!__is_array_unknown_bounds<_Tp>::value, _Tp>;
+#endif
+#endif // smart_ptr_for_overwrite
+#endif // shared_ptr_arrays
+
+  /// @endcond
+
+  /**
+   *  @brief  A smart pointer with reference-counted copy semantics.
+   *  @headerfile memory
+   *  @since C++11
+   *
+   * A `shared_ptr` object is either empty or _owns_ a pointer passed
+   * to the constructor. Copies of a `shared_ptr` share ownership of
+   * the same pointer. When the last `shared_ptr` that owns the pointer
+   * is destroyed or reset, the owned pointer is freed (either by `delete`
+   * or by invoking a custom deleter that was passed to the constructor).
+   *
+   * A `shared_ptr` also stores another pointer, which is usually
+   * (but not always) the same pointer as it owns. The stored pointer
+   * can be retrieved by calling the `get()` member function.
+   *
+   * The equality and relational operators for `shared_ptr` only compare
+   * the stored pointer returned by `get()`, not the owned pointer.
+   * To test whether two `shared_ptr` objects share ownership of the same
+   * pointer see `std::shared_ptr::owner_before` and `std::owner_less`.
+  */
+  template<typename _Tp>
+    class shared_ptr : public __shared_ptr<_Tp>
+    {
+      template<typename... _Args>
+	using _Constructible = typename enable_if<
+	  is_constructible<__shared_ptr<_Tp>, _Args...>::value
+	>::type;
+
+      template<typename _Arg>
+	using _Assignable = typename enable_if<
+	  is_assignable<__shared_ptr<_Tp>&, _Arg>::value, shared_ptr&
+	>::type;
+
+    public:
+
+      /// The type pointed to by the stored pointer, remove_extent_t<_Tp>
+      using element_type = typename __shared_ptr<_Tp>::element_type;
+
+#if __cplusplus >= 201703L
+# define __cpp_lib_shared_ptr_weak_type 201606L
+      /// The corresponding weak_ptr type for this shared_ptr
+      /// @since C++17
+      using weak_type = weak_ptr<_Tp>;
+#endif
+      /**
+       *  @brief  Construct an empty %shared_ptr.
+       *  @post   use_count()==0 && get()==0
+       */
+      constexpr shared_ptr() noexcept : __shared_ptr<_Tp>() { }
+
+      shared_ptr(const shared_ptr&) noexcept = default; ///< Copy constructor
+
+      /**
+       *  @brief  Construct a %shared_ptr that owns the pointer @a __p.
+       *  @param  __p  A pointer that is convertible to element_type*.
+       *  @post   use_count() == 1 && get() == __p
+       *  @throw  std::bad_alloc, in which case @c delete @a __p is called.
+       */
+      template<typename _Yp, typename = _Constructible<_Yp*>>
+	explicit
+	shared_ptr(_Yp* __p) : __shared_ptr<_Tp>(__p) { }
+
+      /**
+       *  @brief  Construct a %shared_ptr that owns the pointer @a __p
+       *          and the deleter @a __d.
+       *  @param  __p  A pointer.
+       *  @param  __d  A deleter.
+       *  @post   use_count() == 1 && get() == __p
+       *  @throw  std::bad_alloc, in which case @a __d(__p) is called.
+       *
+       *  Requirements: _Deleter's copy constructor and destructor must
+       *  not throw
+       *
+       *  __shared_ptr will release __p by calling __d(__p)
+       */
+      template<typename _Yp, typename _Deleter,
+	       typename = _Constructible<_Yp*, _Deleter>>
+	shared_ptr(_Yp* __p, _Deleter __d)
+        : __shared_ptr<_Tp>(__p, std::move(__d)) { }
+
+      /**
+       *  @brief  Construct a %shared_ptr that owns a null pointer
+       *          and the deleter @a __d.
+       *  @param  __p  A null pointer constant.
+       *  @param  __d  A deleter.
+       *  @post   use_count() == 1 && get() == __p
+       *  @throw  std::bad_alloc, in which case @a __d(__p) is called.
+       *
+       *  Requirements: _Deleter's copy constructor and destructor must
+       *  not throw
+       *
+       *  The last owner will call __d(__p)
+       */
+      template<typename _Deleter>
+	shared_ptr(nullptr_t __p, _Deleter __d)
+        : __shared_ptr<_Tp>(__p, std::move(__d)) { }
+
+      /**
+       *  @brief  Construct a %shared_ptr that owns the pointer @a __p
+       *          and the deleter @a __d.
+       *  @param  __p  A pointer.
+       *  @param  __d  A deleter.
+       *  @param  __a  An allocator.
+       *  @post   use_count() == 1 && get() == __p
+       *  @throw  std::bad_alloc, in which case @a __d(__p) is called.
+       *
+       *  Requirements: _Deleter's copy constructor and destructor must
+       *  not throw _Alloc's copy constructor and destructor must not
+       *  throw.
+       *
+       *  __shared_ptr will release __p by calling __d(__p)
+       */
+      template<typename _Yp, typename _Deleter, typename _Alloc,
+	       typename = _Constructible<_Yp*, _Deleter, _Alloc>>
+	shared_ptr(_Yp* __p, _Deleter __d, _Alloc __a)
+	: __shared_ptr<_Tp>(__p, std::move(__d), std::move(__a)) { }
+
+      /**
+       *  @brief  Construct a %shared_ptr that owns a null pointer
+       *          and the deleter @a __d.
+       *  @param  __p  A null pointer constant.
+       *  @param  __d  A deleter.
+       *  @param  __a  An allocator.
+       *  @post   use_count() == 1 && get() == __p
+       *  @throw  std::bad_alloc, in which case @a __d(__p) is called.
+       *
+       *  Requirements: _Deleter's copy constructor and destructor must
+       *  not throw _Alloc's copy constructor and destructor must not
+       *  throw.
+       *
+       *  The last owner will call __d(__p)
+       */
+      template<typename _Deleter, typename _Alloc>
+	shared_ptr(nullptr_t __p, _Deleter __d, _Alloc __a)
+	: __shared_ptr<_Tp>(__p, std::move(__d), std::move(__a)) { }
+
+      // Aliasing constructor
+
+      /**
+       *  @brief  Constructs a `shared_ptr` instance that stores `__p`
+       *          and shares ownership with `__r`.
+       *  @param  __r  A `shared_ptr`.
+       *  @param  __p  A pointer that will remain valid while `*__r` is valid.
+       *  @post   `get() == __p && use_count() == __r.use_count()`
+       *
+       *  This can be used to construct a `shared_ptr` to a sub-object
+       *  of an object managed by an existing `shared_ptr`. The complete
+       *  object will remain valid while any `shared_ptr` owns it, even
+       *  if they don't store a pointer to the complete object.
+       *
+       * @code
+       * shared_ptr<pair<int,int>> pii(new pair<int,int>());
+       * shared_ptr<int> pi(pii, &pii->first);
+       * assert(pii.use_count() == 2);
+       * @endcode
+       */
+      template<typename _Yp>
+	shared_ptr(const shared_ptr<_Yp>& __r, element_type* __p) noexcept
+	: __shared_ptr<_Tp>(__r, __p) { }
+
+#if __cplusplus > 201703L
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 2996. Missing rvalue overloads for shared_ptr operations
+      /**
+       *  @brief  Constructs a `shared_ptr` instance that stores `__p`
+       *          and shares ownership with `__r`.
+       *  @param  __r  A `shared_ptr`.
+       *  @param  __p  A pointer that will remain valid while `*__r` is valid.
+       *  @post   `get() == __p && !__r.use_count() && !__r.get()`
+       *  @since C++17
+       *
+       *  This can be used to construct a `shared_ptr` to a sub-object
+       *  of an object managed by an existing `shared_ptr`. The complete
+       *  object will remain valid while any `shared_ptr` owns it, even
+       *  if they don't store a pointer to the complete object.
+       *
+       * @code
+       * shared_ptr<pair<int,int>> pii(new pair<int,int>());
+       * shared_ptr<int> pi1(pii, &pii->first);
+       * assert(pii.use_count() == 2);
+       * shared_ptr<int> pi2(std::move(pii), &pii->second);
+       * assert(pii.use_count() == 0);
+       * @endcode
+       */
+      template<typename _Yp>
+	shared_ptr(shared_ptr<_Yp>&& __r, element_type* __p) noexcept
+	: __shared_ptr<_Tp>(std::move(__r), __p) { }
+#endif
+      /**
+       *  @brief  If @a __r is empty, constructs an empty %shared_ptr;
+       *          otherwise construct a %shared_ptr that shares ownership
+       *          with @a __r.
+       *  @param  __r  A %shared_ptr.
+       *  @post   get() == __r.get() && use_count() == __r.use_count()
+       */
+      template<typename _Yp,
+	       typename = _Constructible<const shared_ptr<_Yp>&>>
+	shared_ptr(const shared_ptr<_Yp>& __r) noexcept
+        : __shared_ptr<_Tp>(__r) { }
+
+      /**
+       *  @brief  Move-constructs a %shared_ptr instance from @a __r.
+       *  @param  __r  A %shared_ptr rvalue.
+       *  @post   *this contains the old value of @a __r, @a __r is empty.
+       */
+      shared_ptr(shared_ptr&& __r) noexcept
+      : __shared_ptr<_Tp>(std::move(__r)) { }
+
+      /**
+       *  @brief  Move-constructs a %shared_ptr instance from @a __r.
+       *  @param  __r  A %shared_ptr rvalue.
+       *  @post   *this contains the old value of @a __r, @a __r is empty.
+       */
+      template<typename _Yp, typename = _Constructible<shared_ptr<_Yp>>>
+	shared_ptr(shared_ptr<_Yp>&& __r) noexcept
+	: __shared_ptr<_Tp>(std::move(__r)) { }
+
+      /**
+       *  @brief  Constructs a %shared_ptr that shares ownership with @a __r
+       *          and stores a copy of the pointer stored in @a __r.
+       *  @param  __r  A weak_ptr.
+       *  @post   use_count() == __r.use_count()
+       *  @throw  bad_weak_ptr when __r.expired(),
+       *          in which case the constructor has no effect.
+       */
+      template<typename _Yp, typename = _Constructible<const weak_ptr<_Yp>&>>
+	explicit shared_ptr(const weak_ptr<_Yp>& __r)
+	: __shared_ptr<_Tp>(__r) { }
+
+#if _GLIBCXX_USE_DEPRECATED
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+      template<typename _Yp, typename = _Constructible<auto_ptr<_Yp>>>
+	shared_ptr(auto_ptr<_Yp>&& __r);
+#pragma GCC diagnostic pop
+#endif
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 2399. shared_ptr's constructor from unique_ptr should be constrained
+      template<typename _Yp, typename _Del,
+	       typename = _Constructible<unique_ptr<_Yp, _Del>>>
+	shared_ptr(unique_ptr<_Yp, _Del>&& __r)
+	: __shared_ptr<_Tp>(std::move(__r)) { }
+
+#if __cplusplus <= 201402L && _GLIBCXX_USE_DEPRECATED
+      // This non-standard constructor exists to support conversions that
+      // were possible in C++11 and C++14 but are ill-formed in C++17.
+      // If an exception is thrown this constructor has no effect.
+      template<typename _Yp, typename _Del,
+		_Constructible<unique_ptr<_Yp, _Del>, __sp_array_delete>* = 0>
+	shared_ptr(unique_ptr<_Yp, _Del>&& __r)
+	: __shared_ptr<_Tp>(std::move(__r), __sp_array_delete()) { }
+#endif
+
+      /**
+       *  @brief  Construct an empty %shared_ptr.
+       *  @post   use_count() == 0 && get() == nullptr
+       */
+      constexpr shared_ptr(nullptr_t) noexcept : shared_ptr() { }
+
+      shared_ptr& operator=(const shared_ptr&) noexcept = default;
+
+      template<typename _Yp>
+	_Assignable<const shared_ptr<_Yp>&>
+	operator=(const shared_ptr<_Yp>& __r) noexcept
+	{
+	  this->__shared_ptr<_Tp>::operator=(__r);
+	  return *this;
+	}
+
+#if _GLIBCXX_USE_DEPRECATED
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+      template<typename _Yp>
+	_Assignable<auto_ptr<_Yp>>
+	operator=(auto_ptr<_Yp>&& __r)
+	{
+	  this->__shared_ptr<_Tp>::operator=(std::move(__r));
+	  return *this;
+	}
+#pragma GCC diagnostic pop
+#endif
+
+      shared_ptr&
+      operator=(shared_ptr&& __r) noexcept
+      {
+	this->__shared_ptr<_Tp>::operator=(std::move(__r));
+	return *this;
+      }
+
+      template<class _Yp>
+	_Assignable<shared_ptr<_Yp>>
+	operator=(shared_ptr<_Yp>&& __r) noexcept
+	{
+	  this->__shared_ptr<_Tp>::operator=(std::move(__r));
+	  return *this;
+	}
+
+      template<typename _Yp, typename _Del>
+	_Assignable<unique_ptr<_Yp, _Del>>
+	operator=(unique_ptr<_Yp, _Del>&& __r)
+	{
+	  this->__shared_ptr<_Tp>::operator=(std::move(__r));
+	  return *this;
+	}
+
+    private:
+      // This constructor is non-standard, it is used by allocate_shared.
+      template<typename _Alloc, typename... _Args>
+	shared_ptr(_Sp_alloc_shared_tag<_Alloc> __tag, _Args&&... __args)
+	: __shared_ptr<_Tp>(__tag, std::forward<_Args>(__args)...)
+	{ }
+
+      template<typename _Yp, typename _Alloc, typename... _Args>
+	friend shared_ptr<_NonArray<_Yp>>
+	allocate_shared(const _Alloc&, _Args&&...);
+
+      template<typename _Yp, typename... _Args>
+	friend shared_ptr<_NonArray<_Yp>>
+	make_shared(_Args&&...);
+
+#if __cpp_lib_shared_ptr_arrays >= 201707L
+      // This constructor is non-standard, it is used by allocate_shared<T[]>.
+      template<typename _Alloc, typename _Init = const remove_extent_t<_Tp>*>
+	shared_ptr(const _Sp_counted_array_base<_Alloc>& __a,
+		   _Init __init = nullptr)
+	: __shared_ptr<_Tp>(__a, __init)
+	{ }
+
+      template<typename _Yp, typename _Alloc>
+	friend shared_ptr<_UnboundedArray<_Yp>>
+	allocate_shared(const _Alloc&, size_t);
+
+      template<typename _Yp>
+	friend shared_ptr<_UnboundedArray<_Yp>>
+	make_shared(size_t);
+
+      template<typename _Yp, typename _Alloc>
+	friend shared_ptr<_UnboundedArray<_Yp>>
+	allocate_shared(const _Alloc&, size_t, const remove_extent_t<_Yp>&);
+
+      template<typename _Yp>
+	friend shared_ptr<_UnboundedArray<_Yp>>
+	make_shared(size_t, const remove_extent_t<_Yp>&);
+
+      template<typename _Yp, typename _Alloc>
+	friend shared_ptr<_BoundedArray<_Yp>>
+	allocate_shared(const _Alloc&);
+
+      template<typename _Yp>
+	friend shared_ptr<_BoundedArray<_Yp>>
+	make_shared();
+
+      template<typename _Yp, typename _Alloc>
+	friend shared_ptr<_BoundedArray<_Yp>>
+	allocate_shared(const _Alloc&, const remove_extent_t<_Yp>&);
+
+      template<typename _Yp>
+	friend shared_ptr<_BoundedArray<_Yp>>
+	make_shared(const remove_extent_t<_Yp>&);
+
+#if __cpp_lib_smart_ptr_for_overwrite
+      template<typename _Yp, typename _Alloc>
+	friend shared_ptr<_NotUnboundedArray<_Yp>>
+	allocate_shared_for_overwrite(const _Alloc&);
+
+      template<typename _Yp>
+	friend shared_ptr<_NotUnboundedArray<_Yp>>
+	make_shared_for_overwrite();
+
+      template<typename _Yp, typename _Alloc>
+	friend shared_ptr<_UnboundedArray<_Yp>>
+	allocate_shared_for_overwrite(const _Alloc&, size_t);
+
+      template<typename _Yp>
+	friend shared_ptr<_UnboundedArray<_Yp>>
+	make_shared_for_overwrite(size_t);
+#endif
+#endif
+
+      // This constructor is non-standard, it is used by weak_ptr::lock().
+      shared_ptr(const weak_ptr<_Tp>& __r, std::nothrow_t) noexcept
+      : __shared_ptr<_Tp>(__r, std::nothrow) { }
+
+      friend class weak_ptr<_Tp>;
+    };
+
+#if __cpp_deduction_guides >= 201606
+  template<typename _Tp>
+    shared_ptr(weak_ptr<_Tp>) ->  shared_ptr<_Tp>;
+  template<typename _Tp, typename _Del>
+    shared_ptr(unique_ptr<_Tp, _Del>) ->  shared_ptr<_Tp>;
+#endif
+
+  // 20.7.2.2.7 shared_ptr comparisons
+
+  /// @relates shared_ptr @{
+
+  /// Equality operator for shared_ptr objects, compares the stored pointers
+  template<typename _Tp, typename _Up>
+    _GLIBCXX_NODISCARD inline bool
+    operator==(const shared_ptr<_Tp>& __a, const shared_ptr<_Up>& __b) noexcept
+    { return __a.get() == __b.get(); }
+
+  /// shared_ptr comparison with nullptr
+  template<typename _Tp>
+    _GLIBCXX_NODISCARD inline bool
+    operator==(const shared_ptr<_Tp>& __a, nullptr_t) noexcept
+    { return !__a; }
+
+#ifdef __cpp_lib_three_way_comparison
+  template<typename _Tp, typename _Up>
+    inline strong_ordering
+    operator<=>(const shared_ptr<_Tp>& __a,
+		const shared_ptr<_Up>& __b) noexcept
+    { return compare_three_way()(__a.get(), __b.get()); }
+
+  template<typename _Tp>
+    inline strong_ordering
+    operator<=>(const shared_ptr<_Tp>& __a, nullptr_t) noexcept
+    {
+      using pointer = typename shared_ptr<_Tp>::element_type*;
+      return compare_three_way()(__a.get(), static_cast<pointer>(nullptr));
+    }
+#else
+  /// shared_ptr comparison with nullptr
+  template<typename _Tp>
+    _GLIBCXX_NODISCARD inline bool
+    operator==(nullptr_t, const shared_ptr<_Tp>& __a) noexcept
+    { return !__a; }
+
+  /// Inequality operator for shared_ptr objects, compares the stored pointers
+  template<typename _Tp, typename _Up>
+    _GLIBCXX_NODISCARD inline bool
+    operator!=(const shared_ptr<_Tp>& __a, const shared_ptr<_Up>& __b) noexcept
+    { return __a.get() != __b.get(); }
+
+  /// shared_ptr comparison with nullptr
+  template<typename _Tp>
+    _GLIBCXX_NODISCARD inline bool
+    operator!=(const shared_ptr<_Tp>& __a, nullptr_t) noexcept
+    { return (bool)__a; }
+
+  /// shared_ptr comparison with nullptr
+  template<typename _Tp>
+    _GLIBCXX_NODISCARD inline bool
+    operator!=(nullptr_t, const shared_ptr<_Tp>& __a) noexcept
+    { return (bool)__a; }
+
+  /// Relational operator for shared_ptr objects, compares the stored pointers
+  template<typename _Tp, typename _Up>
+    _GLIBCXX_NODISCARD inline bool
+    operator<(const shared_ptr<_Tp>& __a, const shared_ptr<_Up>& __b) noexcept
+    {
+      using _Tp_elt = typename shared_ptr<_Tp>::element_type;
+      using _Up_elt = typename shared_ptr<_Up>::element_type;
+      using _Vp = typename common_type<_Tp_elt*, _Up_elt*>::type;
+      return less<_Vp>()(__a.get(), __b.get());
+    }
+
+  /// shared_ptr comparison with nullptr
+  template<typename _Tp>
+    _GLIBCXX_NODISCARD inline bool
+    operator<(const shared_ptr<_Tp>& __a, nullptr_t) noexcept
+    {
+      using _Tp_elt = typename shared_ptr<_Tp>::element_type;
+      return less<_Tp_elt*>()(__a.get(), nullptr);
+    }
+
+  /// shared_ptr comparison with nullptr
+  template<typename _Tp>
+    _GLIBCXX_NODISCARD inline bool
+    operator<(nullptr_t, const shared_ptr<_Tp>& __a) noexcept
+    {
+      using _Tp_elt = typename shared_ptr<_Tp>::element_type;
+      return less<_Tp_elt*>()(nullptr, __a.get());
+    }
+
+  /// Relational operator for shared_ptr objects, compares the stored pointers
+  template<typename _Tp, typename _Up>
+    _GLIBCXX_NODISCARD inline bool
+    operator<=(const shared_ptr<_Tp>& __a, const shared_ptr<_Up>& __b) noexcept
+    { return !(__b < __a); }
+
+  /// shared_ptr comparison with nullptr
+  template<typename _Tp>
+    _GLIBCXX_NODISCARD inline bool
+    operator<=(const shared_ptr<_Tp>& __a, nullptr_t) noexcept
+    { return !(nullptr < __a); }
+
+  /// shared_ptr comparison with nullptr
+  template<typename _Tp>
+    _GLIBCXX_NODISCARD inline bool
+    operator<=(nullptr_t, const shared_ptr<_Tp>& __a) noexcept
+    { return !(__a < nullptr); }
+
+  /// Relational operator for shared_ptr objects, compares the stored pointers
+  template<typename _Tp, typename _Up>
+    _GLIBCXX_NODISCARD inline bool
+    operator>(const shared_ptr<_Tp>& __a, const shared_ptr<_Up>& __b) noexcept
+    { return (__b < __a); }
+
+  /// shared_ptr comparison with nullptr
+  template<typename _Tp>
+    _GLIBCXX_NODISCARD inline bool
+    operator>(const shared_ptr<_Tp>& __a, nullptr_t) noexcept
+    { return nullptr < __a; }
+
+  /// shared_ptr comparison with nullptr
+  template<typename _Tp>
+    _GLIBCXX_NODISCARD inline bool
+    operator>(nullptr_t, const shared_ptr<_Tp>& __a) noexcept
+    { return __a < nullptr; }
+
+  /// Relational operator for shared_ptr objects, compares the stored pointers
+  template<typename _Tp, typename _Up>
+    _GLIBCXX_NODISCARD inline bool
+    operator>=(const shared_ptr<_Tp>& __a, const shared_ptr<_Up>& __b) noexcept
+    { return !(__a < __b); }
+
+  /// shared_ptr comparison with nullptr
+  template<typename _Tp>
+    _GLIBCXX_NODISCARD inline bool
+    operator>=(const shared_ptr<_Tp>& __a, nullptr_t) noexcept
+    { return !(__a < nullptr); }
+
+  /// shared_ptr comparison with nullptr
+  template<typename _Tp>
+    _GLIBCXX_NODISCARD inline bool
+    operator>=(nullptr_t, const shared_ptr<_Tp>& __a) noexcept
+    { return !(nullptr < __a); }
+#endif
+
+  // 20.7.2.2.8 shared_ptr specialized algorithms.
+
+  /// Swap overload for shared_ptr
+  template<typename _Tp>
+    inline void
+    swap(shared_ptr<_Tp>& __a, shared_ptr<_Tp>& __b) noexcept
+    { __a.swap(__b); }
+
+  // 20.7.2.2.9 shared_ptr casts.
+
+  /// Convert type of `shared_ptr`, via `static_cast`
+  template<typename _Tp, typename _Up>
+    inline shared_ptr<_Tp>
+    static_pointer_cast(const shared_ptr<_Up>& __r) noexcept
+    {
+      using _Sp = shared_ptr<_Tp>;
+      return _Sp(__r, static_cast<typename _Sp::element_type*>(__r.get()));
+    }
+
+  /// Convert type of `shared_ptr`, via `const_cast`
+  template<typename _Tp, typename _Up>
+    inline shared_ptr<_Tp>
+    const_pointer_cast(const shared_ptr<_Up>& __r) noexcept
+    {
+      using _Sp = shared_ptr<_Tp>;
+      return _Sp(__r, const_cast<typename _Sp::element_type*>(__r.get()));
+    }
+
+  /// Convert type of `shared_ptr`, via `dynamic_cast`
+  template<typename _Tp, typename _Up>
+    inline shared_ptr<_Tp>
+    dynamic_pointer_cast(const shared_ptr<_Up>& __r) noexcept
+    {
+      using _Sp = shared_ptr<_Tp>;
+      if (auto* __p = dynamic_cast<typename _Sp::element_type*>(__r.get()))
+	return _Sp(__r, __p);
+      return _Sp();
+    }
+
+#if __cplusplus >= 201703L
+  /// Convert type of `shared_ptr`, via `reinterpret_cast`
+  /// @since C++17
+  template<typename _Tp, typename _Up>
+    inline shared_ptr<_Tp>
+    reinterpret_pointer_cast(const shared_ptr<_Up>& __r) noexcept
+    {
+      using _Sp = shared_ptr<_Tp>;
+      return _Sp(__r, reinterpret_cast<typename _Sp::element_type*>(__r.get()));
+    }
+
+#if __cplusplus > 201703L
+  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+  // 2996. Missing rvalue overloads for shared_ptr operations
+
+  /// Convert type of `shared_ptr` rvalue, via `static_cast`
+  /// @since C++20
+  template<typename _Tp, typename _Up>
+    inline shared_ptr<_Tp>
+    static_pointer_cast(shared_ptr<_Up>&& __r) noexcept
+    {
+      using _Sp = shared_ptr<_Tp>;
+      return _Sp(std::move(__r),
+		 static_cast<typename _Sp::element_type*>(__r.get()));
+    }
+
+  /// Convert type of `shared_ptr` rvalue, via `const_cast`
+  /// @since C++20
+  template<typename _Tp, typename _Up>
+    inline shared_ptr<_Tp>
+    const_pointer_cast(shared_ptr<_Up>&& __r) noexcept
+    {
+      using _Sp = shared_ptr<_Tp>;
+      return _Sp(std::move(__r),
+		 const_cast<typename _Sp::element_type*>(__r.get()));
+    }
+
+  /// Convert type of `shared_ptr` rvalue, via `dynamic_cast`
+  /// @since C++20
+  template<typename _Tp, typename _Up>
+    inline shared_ptr<_Tp>
+    dynamic_pointer_cast(shared_ptr<_Up>&& __r) noexcept
+    {
+      using _Sp = shared_ptr<_Tp>;
+      if (auto* __p = dynamic_cast<typename _Sp::element_type*>(__r.get()))
+	return _Sp(std::move(__r), __p);
+      return _Sp();
+    }
+
+  /// Convert type of `shared_ptr` rvalue, via `reinterpret_cast`
+  /// @since C++20
+  template<typename _Tp, typename _Up>
+    inline shared_ptr<_Tp>
+    reinterpret_pointer_cast(shared_ptr<_Up>&& __r) noexcept
+    {
+      using _Sp = shared_ptr<_Tp>;
+      return _Sp(std::move(__r),
+		 reinterpret_cast<typename _Sp::element_type*>(__r.get()));
+    }
+#endif // C++20
+#endif // C++17
+
+  /// @}
+
+  /**
+   * @brief  A non-owning observer for a pointer owned by a shared_ptr
+   * @headerfile memory
+   * @since C++11
+   *
+   * A weak_ptr provides a safe alternative to a raw pointer when you want
+   * a non-owning reference to an object that is managed by a shared_ptr.
+   *
+   * Unlike a raw pointer, a weak_ptr can be converted to a new shared_ptr
+   * that shares ownership with every other shared_ptr that already owns
+   * the pointer. In other words you can upgrade from a non-owning "weak"
+   * reference to an owning shared_ptr, without having access to any of
+   * the existing shared_ptr objects.
+   *
+   * Also unlike a raw pointer, a weak_ptr does not become "dangling" after
+   * the object it points to has been destroyed. Instead, a weak_ptr
+   * becomes _expired_ and can no longer be converted to a shared_ptr that
+   * owns the freed pointer, so you cannot accidentally access the pointed-to
+   * object after it has been destroyed.
+   */
+  template<typename _Tp>
+    class weak_ptr : public __weak_ptr<_Tp>
+    {
+      template<typename _Arg>
+	using _Constructible = typename enable_if<
+	  is_constructible<__weak_ptr<_Tp>, _Arg>::value
+	>::type;
+
+      template<typename _Arg>
+	using _Assignable = typename enable_if<
+	  is_assignable<__weak_ptr<_Tp>&, _Arg>::value, weak_ptr&
+	>::type;
+
+    public:
+      constexpr weak_ptr() noexcept = default;
+
+      template<typename _Yp,
+	       typename = _Constructible<const shared_ptr<_Yp>&>>
+	weak_ptr(const shared_ptr<_Yp>& __r) noexcept
+	: __weak_ptr<_Tp>(__r) { }
+
+      weak_ptr(const weak_ptr&) noexcept = default;
+
+      template<typename _Yp, typename = _Constructible<const weak_ptr<_Yp>&>>
+	weak_ptr(const weak_ptr<_Yp>& __r) noexcept
+	: __weak_ptr<_Tp>(__r) { }
+
+      weak_ptr(weak_ptr&&) noexcept = default;
+
+      template<typename _Yp, typename = _Constructible<weak_ptr<_Yp>>>
+	weak_ptr(weak_ptr<_Yp>&& __r) noexcept
+	: __weak_ptr<_Tp>(std::move(__r)) { }
+
+      weak_ptr&
+      operator=(const weak_ptr& __r) noexcept = default;
+
+      template<typename _Yp>
+	_Assignable<const weak_ptr<_Yp>&>
+	operator=(const weak_ptr<_Yp>& __r) noexcept
+	{
+	  this->__weak_ptr<_Tp>::operator=(__r);
+	  return *this;
+	}
+
+      template<typename _Yp>
+	_Assignable<const shared_ptr<_Yp>&>
+	operator=(const shared_ptr<_Yp>& __r) noexcept
+	{
+	  this->__weak_ptr<_Tp>::operator=(__r);
+	  return *this;
+	}
+
+      weak_ptr&
+      operator=(weak_ptr&& __r) noexcept = default;
+
+      template<typename _Yp>
+	_Assignable<weak_ptr<_Yp>>
+	operator=(weak_ptr<_Yp>&& __r) noexcept
+	{
+	  this->__weak_ptr<_Tp>::operator=(std::move(__r));
+	  return *this;
+	}
+
+      shared_ptr<_Tp>
+      lock() const noexcept
+      { return shared_ptr<_Tp>(*this, std::nothrow); }
+    };
+
+#if __cpp_deduction_guides >= 201606
+  template<typename _Tp>
+    weak_ptr(shared_ptr<_Tp>) ->  weak_ptr<_Tp>;
+#endif
+
+  // 20.7.2.3.6 weak_ptr specialized algorithms.
+  /// Swap overload for weak_ptr
+  /// @relates weak_ptr
+  template<typename _Tp>
+    inline void
+    swap(weak_ptr<_Tp>& __a, weak_ptr<_Tp>& __b) noexcept
+    { __a.swap(__b); }
+
+
+  /// Primary template owner_less
+  template<typename _Tp = void>
+    struct owner_less;
+
+  /// Void specialization of owner_less compares either shared_ptr or weak_ptr
+  template<>
+    struct owner_less<void> : _Sp_owner_less<void, void>
+    { };
+
+  /// Partial specialization of owner_less for shared_ptr.
+  template<typename _Tp>
+    struct owner_less<shared_ptr<_Tp>>
+    : public _Sp_owner_less<shared_ptr<_Tp>, weak_ptr<_Tp>>
+    { };
+
+  /// Partial specialization of owner_less for weak_ptr.
+  template<typename _Tp>
+    struct owner_less<weak_ptr<_Tp>>
+    : public _Sp_owner_less<weak_ptr<_Tp>, shared_ptr<_Tp>>
+    { };
+
+  /**
+   * @brief Base class allowing use of the member function `shared_from_this`.
+   * @headerfile memory
+   * @since C++11
+   */
+  template<typename _Tp>
+    class enable_shared_from_this
+    {
+    protected:
+      constexpr enable_shared_from_this() noexcept { }
+
+      enable_shared_from_this(const enable_shared_from_this&) noexcept { }
+
+      enable_shared_from_this&
+      operator=(const enable_shared_from_this&) noexcept
+      { return *this; }
+
+      ~enable_shared_from_this() { }
+
+    public:
+      shared_ptr<_Tp>
+      shared_from_this()
+      { return shared_ptr<_Tp>(this->_M_weak_this); }
+
+      shared_ptr<const _Tp>
+      shared_from_this() const
+      { return shared_ptr<const _Tp>(this->_M_weak_this); }
+
+#if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11
+#define __cpp_lib_enable_shared_from_this 201603L
+      /** @{
+       * Get a `weak_ptr` referring to the object that has `*this` as its base.
+       * @since C++17
+       */
+      weak_ptr<_Tp>
+      weak_from_this() noexcept
+      { return this->_M_weak_this; }
+
+      weak_ptr<const _Tp>
+      weak_from_this() const noexcept
+      { return this->_M_weak_this; }
+      /// @}
+#endif
+
+    private:
+      template<typename _Tp1>
+	void
+	_M_weak_assign(_Tp1* __p, const __shared_count<>& __n) const noexcept
+	{ _M_weak_this._M_assign(__p, __n); }
+
+      // Found by ADL when this is an associated class.
+      friend const enable_shared_from_this*
+      __enable_shared_from_this_base(const __shared_count<>&,
+				     const enable_shared_from_this* __p)
+      { return __p; }
+
+      template<typename, _Lock_policy>
+	friend class __shared_ptr;
+
+      mutable weak_ptr<_Tp>  _M_weak_this;
+    };
+
+  /// @relates shared_ptr @{
+
+  /**
+   *  @brief  Create an object that is owned by a shared_ptr.
+   *  @param  __a     An allocator.
+   *  @param  __args  Arguments for the @a _Tp object's constructor.
+   *  @return A shared_ptr that owns the newly created object.
+   *  @throw  An exception thrown from @a _Alloc::allocate or from the
+   *          constructor of @a _Tp.
+   *
+   *  A copy of @a __a will be used to allocate memory for the shared_ptr
+   *  and the new object.
+   */
+  template<typename _Tp, typename _Alloc, typename... _Args>
+    inline shared_ptr<_NonArray<_Tp>>
+    allocate_shared(const _Alloc& __a, _Args&&... __args)
+    {
+      return shared_ptr<_Tp>(_Sp_alloc_shared_tag<_Alloc>{__a},
+			     std::forward<_Args>(__args)...);
+    }
+
+  /**
+   *  @brief  Create an object that is owned by a shared_ptr.
+   *  @param  __args  Arguments for the @a _Tp object's constructor.
+   *  @return A shared_ptr that owns the newly created object.
+   *  @throw  std::bad_alloc, or an exception thrown from the
+   *          constructor of @a _Tp.
+   */
+  template<typename _Tp, typename... _Args>
+    inline shared_ptr<_NonArray<_Tp>>
+    make_shared(_Args&&... __args)
+    {
+      using _Alloc = allocator<void>;
+      _Alloc __a;
+      return shared_ptr<_Tp>(_Sp_alloc_shared_tag<_Alloc>{__a},
+			     std::forward<_Args>(__args)...);
+    }
+
+#if __cpp_lib_shared_ptr_arrays >= 201707L
+  /// @cond undocumented
+  template<typename _Tp, typename _Alloc = allocator<void>>
+    auto
+    __make_shared_arr_tag(size_t __n, const _Alloc& __a = _Alloc()) noexcept
+    {
+      using _Up = remove_all_extents_t<_Tp>;
+      using _UpAlloc = __alloc_rebind<_Alloc, _Up>;
+      size_t __s = sizeof(remove_extent_t<_Tp>) / sizeof(_Up);
+      if (__builtin_mul_overflow(__s, __n, &__n))
+	std::__throw_bad_array_new_length();
+      return _Sp_counted_array_base<_UpAlloc>{_UpAlloc(__a), __n};
+    }
+  /// @endcond
+
+  template<typename _Tp, typename _Alloc>
+    inline shared_ptr<_UnboundedArray<_Tp>>
+    allocate_shared(const _Alloc& __a, size_t __n)
+    {
+      return shared_ptr<_Tp>(std::__make_shared_arr_tag<_Tp>(__n, __a));
+    }
+
+  template<typename _Tp>
+    inline shared_ptr<_UnboundedArray<_Tp>>
+    make_shared(size_t __n)
+    {
+      return shared_ptr<_Tp>(std::__make_shared_arr_tag<_Tp>(__n));
+    }
+
+  template<typename _Tp, typename _Alloc>
+    inline shared_ptr<_UnboundedArray<_Tp>>
+    allocate_shared(const _Alloc& __a, size_t __n,
+		    const remove_extent_t<_Tp>& __u)
+    {
+      return shared_ptr<_Tp>(std::__make_shared_arr_tag<_Tp>(__n, __a),
+			     std::__addressof(__u));
+    }
+
+  template<typename _Tp>
+    inline shared_ptr<_UnboundedArray<_Tp>>
+    make_shared(size_t __n, const remove_extent_t<_Tp>& __u)
+    {
+      return shared_ptr<_Tp>(std::__make_shared_arr_tag<_Tp>(__n),
+			     std::__addressof(__u));
+    }
+
+  /// @cond undocumented
+  template<typename _Tp, typename _Alloc = allocator<void>>
+    auto
+    __make_shared_arrN_tag(const _Alloc& __a = _Alloc()) noexcept
+    {
+      using _Up = remove_all_extents_t<_Tp>;
+      using _UpAlloc = __alloc_rebind<_Alloc, _Up>;
+      size_t __n = sizeof(_Tp) / sizeof(_Up);
+      return _Sp_counted_array_base<_UpAlloc>{_UpAlloc(__a), __n};
+    }
+  /// @endcond
+
+  template<typename _Tp, typename _Alloc>
+    inline shared_ptr<_BoundedArray<_Tp>>
+    allocate_shared(const _Alloc& __a)
+    {
+      return shared_ptr<_Tp>(std::__make_shared_arrN_tag<_Tp>(__a));
+    }
+
+  template<typename _Tp>
+    inline shared_ptr<_BoundedArray<_Tp>>
+    make_shared()
+    {
+      return shared_ptr<_Tp>(std::__make_shared_arrN_tag<_Tp>());
+    }
+
+  template<typename _Tp, typename _Alloc>
+    inline shared_ptr<_BoundedArray<_Tp>>
+    allocate_shared(const _Alloc& __a, const remove_extent_t<_Tp>& __u)
+    {
+      return shared_ptr<_Tp>(std::__make_shared_arrN_tag<_Tp>(__a),
+			     std::__addressof(__u));
+    }
+
+  template<typename _Tp>
+    inline shared_ptr<_BoundedArray<_Tp>>
+    make_shared(const remove_extent_t<_Tp>& __u)
+    {
+      return shared_ptr<_Tp>(std::__make_shared_arrN_tag<_Tp>(),
+			     std::__addressof(__u));
+    }
+
+#if __cpp_lib_smart_ptr_for_overwrite
+  template<typename _Tp, typename _Alloc>
+    inline shared_ptr<_NotUnboundedArray<_Tp>>
+    allocate_shared_for_overwrite(const _Alloc& __a)
+    {
+      if constexpr (is_array_v<_Tp>)
+	return shared_ptr<_Tp>(std::__make_shared_arrN_tag<_Tp>(__a),
+			       _Sp_overwrite_tag{});
+      else
+	{
+	  // Rebind the allocator to _Sp_overwrite_tag, so that the
+	  // relevant _Sp_counted_ptr_inplace specialization is used.
+	  using _Alloc2 = __alloc_rebind<_Alloc, _Sp_overwrite_tag>;
+	  _Alloc2 __a2 = __a;
+	  return shared_ptr<_Tp>(_Sp_alloc_shared_tag<_Alloc2>{__a2});
+	}
+    }
+
+  template<typename _Tp>
+    inline shared_ptr<_NotUnboundedArray<_Tp>>
+    make_shared_for_overwrite()
+    {
+      if constexpr (is_array_v<_Tp>)
+	return shared_ptr<_Tp>(std::__make_shared_arrN_tag<_Tp>(),
+			       _Sp_overwrite_tag{});
+      else
+	{
+	  using _Alloc = allocator<_Sp_overwrite_tag>;
+	  return shared_ptr<_Tp>(_Sp_alloc_shared_tag<_Alloc>{{}});
+	}
+    }
+
+  template<typename _Tp, typename _Alloc>
+    inline shared_ptr<_UnboundedArray<_Tp>>
+    allocate_shared_for_overwrite(const _Alloc& __a, size_t __n)
+    {
+      return shared_ptr<_Tp>(std::__make_shared_arr_tag<_Tp>(__n, __a),
+			     _Sp_overwrite_tag{});
+    }
+
+  template<typename _Tp>
+    inline shared_ptr<_UnboundedArray<_Tp>>
+    make_shared_for_overwrite(size_t __n)
+    {
+      return shared_ptr<_Tp>(std::__make_shared_arr_tag<_Tp>(__n),
+			     _Sp_overwrite_tag{});
+    }
+#endif // smart_ptr_for_overwrite
+#endif // shared_ptr_arrays
+
+  /// std::hash specialization for shared_ptr.
+  template<typename _Tp>
+    struct hash<shared_ptr<_Tp>>
+    : public __hash_base<size_t, shared_ptr<_Tp>>
+    {
+      size_t
+      operator()(const shared_ptr<_Tp>& __s) const noexcept
+      {
+	return std::hash<typename shared_ptr<_Tp>::element_type*>()(__s.get());
+      }
+    };
+
+  /// @} relates shared_ptr
+  /// @} group pointer_abstractions
+
+#if __cplusplus >= 201703L
+  namespace __detail::__variant
+  {
+    template<typename> struct _Never_valueless_alt; // see <variant>
+
+    // Provide the strong exception-safety guarantee when emplacing a
+    // shared_ptr into a variant.
+    template<typename _Tp>
+      struct _Never_valueless_alt<std::shared_ptr<_Tp>>
+      : std::true_type
+      { };
+
+    // Provide the strong exception-safety guarantee when emplacing a
+    // weak_ptr into a variant.
+    template<typename _Tp>
+      struct _Never_valueless_alt<std::weak_ptr<_Tp>>
+      : std::true_type
+      { };
+  }  // namespace __detail::__variant
+#endif // C++17
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif // _SHARED_PTR_H
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@@ -0,0 +1,799 @@
+// shared_ptr atomic access -*- C++ -*-
+
+// Copyright (C) 2014-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/shared_ptr_atomic.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{memory}
+ */
+
+#ifndef _SHARED_PTR_ATOMIC_H
+#define _SHARED_PTR_ATOMIC_H 1
+
+#include <bits/atomic_base.h>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /**
+   * @addtogroup pointer_abstractions
+   * @{
+   */
+  /// @relates shared_ptr @{
+
+  /// @cond undocumented
+
+  struct _Sp_locker
+  {
+    _Sp_locker(const _Sp_locker&) = delete;
+    _Sp_locker& operator=(const _Sp_locker&) = delete;
+
+#ifdef __GTHREADS
+    explicit
+    _Sp_locker(const void*) noexcept;
+    _Sp_locker(const void*, const void*) noexcept;
+    ~_Sp_locker();
+
+  private:
+    unsigned char _M_key1;
+    unsigned char _M_key2;
+#else
+    explicit _Sp_locker(const void*, const void* = nullptr) { }
+#endif
+  };
+
+  /// @endcond
+
+  /**
+   *  @brief  Report whether shared_ptr atomic operations are lock-free.
+   *  @param  __p A non-null pointer to a shared_ptr object.
+   *  @return True if atomic access to @c *__p is lock-free, false otherwise.
+   *  @{
+  */
+  template<typename _Tp, _Lock_policy _Lp>
+    inline bool
+    atomic_is_lock_free(const __shared_ptr<_Tp, _Lp>* __p)
+    {
+#ifdef __GTHREADS
+      return __gthread_active_p() == 0;
+#else
+      return true;
+#endif
+    }
+
+  template<typename _Tp>
+    inline bool
+    atomic_is_lock_free(const shared_ptr<_Tp>* __p)
+    { return std::atomic_is_lock_free<_Tp, __default_lock_policy>(__p); }
+
+  /// @}
+
+  /**
+   *  @brief  Atomic load for shared_ptr objects.
+   *  @param  __p A non-null pointer to a shared_ptr object.
+   *  @return @c *__p
+   *
+   *  The memory order shall not be @c memory_order_release or
+   *  @c memory_order_acq_rel.
+   *  @{
+  */
+  template<typename _Tp>
+    inline shared_ptr<_Tp>
+    atomic_load_explicit(const shared_ptr<_Tp>* __p, memory_order)
+    {
+      _Sp_locker __lock{__p};
+      return *__p;
+    }
+
+  template<typename _Tp>
+    inline shared_ptr<_Tp>
+    atomic_load(const shared_ptr<_Tp>* __p)
+    { return std::atomic_load_explicit(__p, memory_order_seq_cst); }
+
+  template<typename _Tp, _Lock_policy _Lp>
+    inline __shared_ptr<_Tp, _Lp>
+    atomic_load_explicit(const __shared_ptr<_Tp, _Lp>* __p, memory_order)
+    {
+      _Sp_locker __lock{__p};
+      return *__p;
+    }
+
+  template<typename _Tp, _Lock_policy _Lp>
+    inline __shared_ptr<_Tp, _Lp>
+    atomic_load(const __shared_ptr<_Tp, _Lp>* __p)
+    { return std::atomic_load_explicit(__p, memory_order_seq_cst); }
+  /// @}
+
+  /**
+   *  @brief  Atomic store for shared_ptr objects.
+   *  @param  __p A non-null pointer to a shared_ptr object.
+   *  @param  __r The value to store.
+   *
+   *  The memory order shall not be @c memory_order_acquire or
+   *  @c memory_order_acq_rel.
+   *  @{
+  */
+  template<typename _Tp>
+    inline void
+    atomic_store_explicit(shared_ptr<_Tp>* __p, shared_ptr<_Tp> __r,
+			  memory_order)
+    {
+      _Sp_locker __lock{__p};
+      __p->swap(__r); // use swap so that **__p not destroyed while lock held
+    }
+
+  template<typename _Tp>
+    inline void
+    atomic_store(shared_ptr<_Tp>* __p, shared_ptr<_Tp> __r)
+    { std::atomic_store_explicit(__p, std::move(__r), memory_order_seq_cst); }
+
+  template<typename _Tp, _Lock_policy _Lp>
+    inline void
+    atomic_store_explicit(__shared_ptr<_Tp, _Lp>* __p,
+			  __shared_ptr<_Tp, _Lp> __r,
+			  memory_order)
+    {
+      _Sp_locker __lock{__p};
+      __p->swap(__r); // use swap so that **__p not destroyed while lock held
+    }
+
+  template<typename _Tp, _Lock_policy _Lp>
+    inline void
+    atomic_store(__shared_ptr<_Tp, _Lp>* __p, __shared_ptr<_Tp, _Lp> __r)
+    { std::atomic_store_explicit(__p, std::move(__r), memory_order_seq_cst); }
+  /// @}
+
+  /**
+   *  @brief  Atomic exchange for shared_ptr objects.
+   *  @param  __p A non-null pointer to a shared_ptr object.
+   *  @param  __r New value to store in @c *__p.
+   *  @return The original value of @c *__p
+   *  @{
+  */
+  template<typename _Tp>
+    inline shared_ptr<_Tp>
+    atomic_exchange_explicit(shared_ptr<_Tp>* __p, shared_ptr<_Tp> __r,
+			     memory_order)
+    {
+      _Sp_locker __lock{__p};
+      __p->swap(__r);
+      return __r;
+    }
+
+  template<typename _Tp>
+    inline shared_ptr<_Tp>
+    atomic_exchange(shared_ptr<_Tp>* __p, shared_ptr<_Tp> __r)
+    {
+      return std::atomic_exchange_explicit(__p, std::move(__r),
+					   memory_order_seq_cst);
+    }
+
+  template<typename _Tp, _Lock_policy _Lp>
+    inline __shared_ptr<_Tp, _Lp>
+    atomic_exchange_explicit(__shared_ptr<_Tp, _Lp>* __p,
+			     __shared_ptr<_Tp, _Lp> __r,
+			     memory_order)
+    {
+      _Sp_locker __lock{__p};
+      __p->swap(__r);
+      return __r;
+    }
+
+  template<typename _Tp, _Lock_policy _Lp>
+    inline __shared_ptr<_Tp, _Lp>
+    atomic_exchange(__shared_ptr<_Tp, _Lp>* __p, __shared_ptr<_Tp, _Lp> __r)
+    {
+      return std::atomic_exchange_explicit(__p, std::move(__r),
+					   memory_order_seq_cst);
+    }
+  /// @}
+
+  /**
+   *  @brief  Atomic compare-and-swap for shared_ptr objects.
+   *  @param  __p A non-null pointer to a shared_ptr object.
+   *  @param  __v A non-null pointer to a shared_ptr object.
+   *  @param  __w A non-null pointer to a shared_ptr object.
+   *  @return True if @c *__p was equivalent to @c *__v, false otherwise.
+   *
+   *  The memory order for failure shall not be @c memory_order_release or
+   *  @c memory_order_acq_rel, or stronger than the memory order for success.
+   *  @{
+  */
+  template<typename _Tp>
+    bool
+    atomic_compare_exchange_strong_explicit(shared_ptr<_Tp>* __p,
+					    shared_ptr<_Tp>* __v,
+					    shared_ptr<_Tp> __w,
+					    memory_order,
+					    memory_order)
+    {
+      shared_ptr<_Tp> __x; // goes out of scope after __lock
+      _Sp_locker __lock{__p, __v};
+      owner_less<shared_ptr<_Tp>> __less;
+      if (*__p == *__v && !__less(*__p, *__v) && !__less(*__v, *__p))
+	{
+	  __x = std::move(*__p);
+	  *__p = std::move(__w);
+	  return true;
+	}
+      __x = std::move(*__v);
+      *__v = *__p;
+      return false;
+    }
+
+  template<typename _Tp>
+    inline bool
+    atomic_compare_exchange_strong(shared_ptr<_Tp>* __p, shared_ptr<_Tp>* __v,
+				 shared_ptr<_Tp> __w)
+    {
+      return std::atomic_compare_exchange_strong_explicit(__p, __v,
+	  std::move(__w), memory_order_seq_cst, memory_order_seq_cst);
+    }
+
+  template<typename _Tp>
+    inline bool
+    atomic_compare_exchange_weak_explicit(shared_ptr<_Tp>* __p,
+					  shared_ptr<_Tp>* __v,
+					  shared_ptr<_Tp> __w,
+					  memory_order __success,
+					  memory_order __failure)
+    {
+      return std::atomic_compare_exchange_strong_explicit(__p, __v,
+	  std::move(__w), __success, __failure);
+    }
+
+  template<typename _Tp>
+    inline bool
+    atomic_compare_exchange_weak(shared_ptr<_Tp>* __p, shared_ptr<_Tp>* __v,
+				 shared_ptr<_Tp> __w)
+    {
+      return std::atomic_compare_exchange_weak_explicit(__p, __v,
+	  std::move(__w), memory_order_seq_cst, memory_order_seq_cst);
+    }
+
+  template<typename _Tp, _Lock_policy _Lp>
+    bool
+    atomic_compare_exchange_strong_explicit(__shared_ptr<_Tp, _Lp>* __p,
+					    __shared_ptr<_Tp, _Lp>* __v,
+					    __shared_ptr<_Tp, _Lp> __w,
+					    memory_order,
+					    memory_order)
+    {
+      __shared_ptr<_Tp, _Lp> __x; // goes out of scope after __lock
+      _Sp_locker __lock{__p, __v};
+      owner_less<__shared_ptr<_Tp, _Lp>> __less;
+      if (*__p == *__v && !__less(*__p, *__v) && !__less(*__v, *__p))
+	{
+	  __x = std::move(*__p);
+	  *__p = std::move(__w);
+	  return true;
+	}
+      __x = std::move(*__v);
+      *__v = *__p;
+      return false;
+    }
+
+  template<typename _Tp, _Lock_policy _Lp>
+    inline bool
+    atomic_compare_exchange_strong(__shared_ptr<_Tp, _Lp>* __p,
+				   __shared_ptr<_Tp, _Lp>* __v,
+				   __shared_ptr<_Tp, _Lp> __w)
+    {
+      return std::atomic_compare_exchange_strong_explicit(__p, __v,
+	  std::move(__w), memory_order_seq_cst, memory_order_seq_cst);
+    }
+
+  template<typename _Tp, _Lock_policy _Lp>
+    inline bool
+    atomic_compare_exchange_weak_explicit(__shared_ptr<_Tp, _Lp>* __p,
+					  __shared_ptr<_Tp, _Lp>* __v,
+					  __shared_ptr<_Tp, _Lp> __w,
+					  memory_order __success,
+					  memory_order __failure)
+    {
+      return std::atomic_compare_exchange_strong_explicit(__p, __v,
+	  std::move(__w), __success, __failure);
+    }
+
+  template<typename _Tp, _Lock_policy _Lp>
+    inline bool
+    atomic_compare_exchange_weak(__shared_ptr<_Tp, _Lp>* __p,
+				 __shared_ptr<_Tp, _Lp>* __v,
+				 __shared_ptr<_Tp, _Lp> __w)
+    {
+      return std::atomic_compare_exchange_weak_explicit(__p, __v,
+	  std::move(__w), memory_order_seq_cst, memory_order_seq_cst);
+    }
+  /// @}
+
+#if __cplusplus >= 202002L
+# define __cpp_lib_atomic_shared_ptr 201711L
+  template<typename _Tp>
+    class atomic;
+
+  template<typename _Up>
+    static constexpr bool __is_shared_ptr = false;
+  template<typename _Up>
+    static constexpr bool __is_shared_ptr<shared_ptr<_Up>> = true;
+
+  template<typename _Tp>
+    class _Sp_atomic
+    {
+      using value_type = _Tp;
+
+      friend class atomic<_Tp>;
+
+      // An atomic version of __shared_count<> and __weak_count<>.
+      // Stores a _Sp_counted_base<>* but uses the LSB as a lock.
+      struct _Atomic_count
+      {
+	// Either __shared_count<> or __weak_count<>
+	using __count_type = decltype(_Tp::_M_refcount);
+
+	// _Sp_counted_base<>*
+	using pointer = decltype(__count_type::_M_pi);
+
+	// Ensure we can use the LSB as the lock bit.
+	static_assert(alignof(remove_pointer_t<pointer>) > 1);
+
+	constexpr _Atomic_count() noexcept = default;
+
+	explicit
+	_Atomic_count(__count_type&& __c) noexcept
+	: _M_val(reinterpret_cast<uintptr_t>(__c._M_pi))
+	{
+	  __c._M_pi = nullptr;
+	}
+
+	~_Atomic_count()
+	{
+	  auto __val = _M_val.load(memory_order_relaxed);
+	  __glibcxx_assert(!(__val & _S_lock_bit));
+	  if (auto __pi = reinterpret_cast<pointer>(__val))
+	    {
+	      if constexpr (__is_shared_ptr<_Tp>)
+		__pi->_M_release();
+	      else
+		__pi->_M_weak_release();
+	    }
+	}
+
+	_Atomic_count(const _Atomic_count&) = delete;
+	_Atomic_count& operator=(const _Atomic_count&) = delete;
+
+	// Precondition: Caller does not hold lock!
+	// Returns the raw pointer value without the lock bit set.
+	pointer
+	lock(memory_order __o) const noexcept
+	{
+	  // To acquire the lock we flip the LSB from 0 to 1.
+
+	  auto __current = _M_val.load(memory_order_relaxed);
+	  while (__current & _S_lock_bit)
+	    {
+#if __cpp_lib_atomic_wait
+	      __detail::__thread_relax();
+#endif
+	      __current = _M_val.load(memory_order_relaxed);
+	    }
+
+	  while (!_M_val.compare_exchange_strong(__current,
+						 __current | _S_lock_bit,
+						 __o,
+						 memory_order_relaxed))
+	    {
+#if __cpp_lib_atomic_wait
+	      __detail::__thread_relax();
+#endif
+	      __current = __current & ~_S_lock_bit;
+	    }
+	  return reinterpret_cast<pointer>(__current);
+	}
+
+	// Precondition: caller holds lock!
+	void
+	unlock(memory_order __o) const noexcept
+	{
+	  _M_val.fetch_sub(1, __o);
+	}
+
+	// Swaps the values of *this and __c, and unlocks *this.
+	// Precondition: caller holds lock!
+	void
+	_M_swap_unlock(__count_type& __c, memory_order __o) noexcept
+	{
+	  if (__o != memory_order_seq_cst)
+	    __o = memory_order_release;
+	  auto __x = reinterpret_cast<uintptr_t>(__c._M_pi);
+	  __x = _M_val.exchange(__x, __o);
+	  __c._M_pi = reinterpret_cast<pointer>(__x & ~_S_lock_bit);
+	}
+
+#if __cpp_lib_atomic_wait
+	// Precondition: caller holds lock!
+	void
+	_M_wait_unlock(memory_order __o) const noexcept
+	{
+	  auto __v = _M_val.fetch_sub(1, memory_order_relaxed);
+	  _M_val.wait(__v & ~_S_lock_bit, __o);
+	}
+
+	void
+	notify_one() noexcept
+	{
+	  _M_val.notify_one();
+	}
+
+	void
+	notify_all() noexcept
+	{
+	  _M_val.notify_all();
+	}
+#endif
+
+      private:
+	mutable __atomic_base<uintptr_t> _M_val{0};
+	static constexpr uintptr_t _S_lock_bit{1};
+      };
+
+      typename _Tp::element_type* _M_ptr = nullptr;
+      _Atomic_count _M_refcount;
+
+      static typename _Atomic_count::pointer
+      _S_add_ref(typename _Atomic_count::pointer __p)
+      {
+	if (__p)
+	  {
+	    if constexpr (__is_shared_ptr<_Tp>)
+	      __p->_M_add_ref_copy();
+	    else
+	      __p->_M_weak_add_ref();
+	  }
+	return __p;
+      }
+
+      constexpr _Sp_atomic() noexcept = default;
+
+      explicit
+      _Sp_atomic(value_type __r) noexcept
+      : _M_ptr(__r._M_ptr), _M_refcount(std::move(__r._M_refcount))
+      { }
+
+      ~_Sp_atomic() = default;
+
+      _Sp_atomic(const _Sp_atomic&) = delete;
+      void operator=(const _Sp_atomic&) = delete;
+
+      value_type
+      load(memory_order __o) const noexcept
+      {
+	__glibcxx_assert(__o != memory_order_release
+			   && __o != memory_order_acq_rel);
+	// Ensure that the correct value of _M_ptr is visible after locking.,
+	// by upgrading relaxed or consume to acquire.
+	if (__o != memory_order_seq_cst)
+	  __o = memory_order_acquire;
+
+	value_type __ret;
+	auto __pi = _M_refcount.lock(__o);
+	__ret._M_ptr = _M_ptr;
+	__ret._M_refcount._M_pi = _S_add_ref(__pi);
+	_M_refcount.unlock(memory_order_relaxed);
+	return __ret;
+      }
+
+      void
+      swap(value_type& __r, memory_order __o) noexcept
+      {
+	_M_refcount.lock(memory_order_acquire);
+	std::swap(_M_ptr, __r._M_ptr);
+	_M_refcount._M_swap_unlock(__r._M_refcount, __o);
+      }
+
+      bool
+      compare_exchange_strong(value_type& __expected, value_type __desired,
+			      memory_order __o, memory_order __o2) noexcept
+      {
+	bool __result = true;
+	auto __pi = _M_refcount.lock(memory_order_acquire);
+	if (_M_ptr == __expected._M_ptr
+	      && __pi == __expected._M_refcount._M_pi)
+	  {
+	    _M_ptr = __desired._M_ptr;
+	    _M_refcount._M_swap_unlock(__desired._M_refcount, __o);
+	  }
+	else
+	  {
+	    _Tp __sink = std::move(__expected);
+	    __expected._M_ptr = _M_ptr;
+	    __expected._M_refcount._M_pi = _S_add_ref(__pi);
+	    _M_refcount.unlock(__o2);
+	    __result = false;
+	  }
+	return __result;
+      }
+
+#if __cpp_lib_atomic_wait
+      void
+      wait(value_type __old, memory_order __o) const noexcept
+      {
+	auto __pi = _M_refcount.lock(memory_order_acquire);
+	if (_M_ptr == __old._M_ptr && __pi == __old._M_refcount._M_pi)
+	  _M_refcount._M_wait_unlock(__o);
+	else
+	  _M_refcount.unlock(memory_order_relaxed);
+      }
+
+      void
+      notify_one() noexcept
+      {
+	_M_refcount.notify_one();
+      }
+
+      void
+      notify_all() noexcept
+      {
+	_M_refcount.notify_all();
+      }
+#endif
+    };
+
+  template<typename _Tp>
+    class atomic<shared_ptr<_Tp>>
+    {
+    public:
+      using value_type = shared_ptr<_Tp>;
+
+      static constexpr bool is_always_lock_free = false;
+
+      bool
+      is_lock_free() const noexcept
+      { return false; }
+
+      constexpr atomic() noexcept = default;
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 3661. constinit atomic<shared_ptr<T>> a(nullptr); should work
+      constexpr atomic(nullptr_t) noexcept : atomic() { }
+
+      atomic(shared_ptr<_Tp> __r) noexcept
+      : _M_impl(std::move(__r))
+      { }
+
+      atomic(const atomic&) = delete;
+      void operator=(const atomic&) = delete;
+
+      shared_ptr<_Tp>
+      load(memory_order __o = memory_order_seq_cst) const noexcept
+      { return _M_impl.load(__o); }
+
+      operator shared_ptr<_Tp>() const noexcept
+      { return _M_impl.load(memory_order_seq_cst); }
+
+      void
+      store(shared_ptr<_Tp> __desired,
+	    memory_order __o = memory_order_seq_cst) noexcept
+      { _M_impl.swap(__desired, __o); }
+
+      void
+      operator=(shared_ptr<_Tp> __desired) noexcept
+      { _M_impl.swap(__desired, memory_order_seq_cst); }
+
+      shared_ptr<_Tp>
+      exchange(shared_ptr<_Tp> __desired,
+	       memory_order __o = memory_order_seq_cst) noexcept
+      {
+	_M_impl.swap(__desired, __o);
+	return __desired;
+      }
+
+      bool
+      compare_exchange_strong(shared_ptr<_Tp>& __expected,
+			      shared_ptr<_Tp> __desired,
+			      memory_order __o, memory_order __o2) noexcept
+      {
+	return _M_impl.compare_exchange_strong(__expected, __desired, __o, __o2);
+      }
+
+      bool
+      compare_exchange_strong(value_type& __expected, value_type __desired,
+			      memory_order __o = memory_order_seq_cst) noexcept
+      {
+	memory_order __o2;
+	switch (__o)
+	{
+	case memory_order_acq_rel:
+	  __o2 = memory_order_acquire;
+	  break;
+	case memory_order_release:
+	  __o2 = memory_order_relaxed;
+	  break;
+	default:
+	  __o2 = __o;
+	}
+	return compare_exchange_strong(__expected, std::move(__desired),
+				       __o, __o2);
+      }
+
+      bool
+      compare_exchange_weak(value_type& __expected, value_type __desired,
+			    memory_order __o, memory_order __o2) noexcept
+      {
+	return compare_exchange_strong(__expected, std::move(__desired),
+				       __o, __o2);
+      }
+
+      bool
+      compare_exchange_weak(value_type& __expected, value_type __desired,
+			    memory_order __o = memory_order_seq_cst) noexcept
+      {
+	return compare_exchange_strong(__expected, std::move(__desired), __o);
+      }
+
+#if __cpp_lib_atomic_wait
+      void
+      wait(value_type __old,
+	   memory_order __o = memory_order_seq_cst) const noexcept
+      {
+	_M_impl.wait(std::move(__old), __o);
+      }
+
+      void
+      notify_one() noexcept
+      {
+	_M_impl.notify_one();
+      }
+
+      void
+      notify_all() noexcept
+      {
+	_M_impl.notify_all();
+      }
+#endif
+
+    private:
+      _Sp_atomic<shared_ptr<_Tp>> _M_impl;
+    };
+
+  template<typename _Tp>
+    class atomic<weak_ptr<_Tp>>
+    {
+    public:
+      using value_type = weak_ptr<_Tp>;
+
+      static constexpr bool is_always_lock_free = false;
+
+      bool
+      is_lock_free() const noexcept
+      { return false; }
+
+      constexpr atomic() noexcept = default;
+
+      atomic(weak_ptr<_Tp> __r) noexcept
+     : _M_impl(move(__r))
+      { }
+
+      atomic(const atomic&) = delete;
+      void operator=(const atomic&) = delete;
+
+      weak_ptr<_Tp>
+      load(memory_order __o = memory_order_seq_cst) const noexcept
+      { return _M_impl.load(__o); }
+
+      operator weak_ptr<_Tp>() const noexcept
+      { return _M_impl.load(memory_order_seq_cst); }
+
+      void
+      store(weak_ptr<_Tp> __desired,
+	    memory_order __o = memory_order_seq_cst) noexcept
+      { _M_impl.swap(__desired, __o); }
+
+      void
+      operator=(weak_ptr<_Tp> __desired) noexcept
+      { _M_impl.swap(__desired, memory_order_seq_cst); }
+
+      weak_ptr<_Tp>
+      exchange(weak_ptr<_Tp> __desired,
+	       memory_order __o = memory_order_seq_cst) noexcept
+      {
+	_M_impl.swap(__desired, __o);
+	return __desired;
+      }
+
+      bool
+      compare_exchange_strong(weak_ptr<_Tp>& __expected,
+			      weak_ptr<_Tp> __desired,
+			      memory_order __o, memory_order __o2) noexcept
+      {
+	return _M_impl.compare_exchange_strong(__expected, __desired, __o, __o2);
+      }
+
+      bool
+      compare_exchange_strong(value_type& __expected, value_type __desired,
+			      memory_order __o = memory_order_seq_cst) noexcept
+      {
+	memory_order __o2;
+	switch (__o)
+	{
+	case memory_order_acq_rel:
+	  __o2 = memory_order_acquire;
+	  break;
+	case memory_order_release:
+	  __o2 = memory_order_relaxed;
+	  break;
+	default:
+	  __o2 = __o;
+	}
+	return compare_exchange_strong(__expected, std::move(__desired),
+				       __o, __o2);
+      }
+
+      bool
+      compare_exchange_weak(value_type& __expected, value_type __desired,
+			    memory_order __o, memory_order __o2) noexcept
+      {
+	return compare_exchange_strong(__expected, std::move(__desired),
+				       __o, __o2);
+      }
+
+      bool
+      compare_exchange_weak(value_type& __expected, value_type __desired,
+			    memory_order __o = memory_order_seq_cst) noexcept
+      {
+	return compare_exchange_strong(__expected, std::move(__desired), __o);
+      }
+
+#if __cpp_lib_atomic_wait
+      void
+      wait(value_type __old,
+	   memory_order __o = memory_order_seq_cst) const noexcept
+      {
+	_M_impl.wait(std::move(__old), __o);
+      }
+
+      void
+      notify_one() noexcept
+      {
+	_M_impl.notify_one();
+      }
+
+      void
+      notify_all() noexcept
+      {
+	_M_impl.notify_all();
+      }
+#endif
+
+    private:
+      _Sp_atomic<weak_ptr<_Tp>> _M_impl;
+    };
+#endif // C++20
+
+  /// @} relates shared_ptr
+  /// @} group pointer_abstractions
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif // _SHARED_PTR_ATOMIC_H
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@@ -0,0 +1,2260 @@
+// shared_ptr and weak_ptr implementation details -*- C++ -*-
+
+// Copyright (C) 2007-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+// GCC Note: Based on files from version 1.32.0 of the Boost library.
+
+//  shared_count.hpp
+//  Copyright (c) 2001, 2002, 2003 Peter Dimov and Multi Media Ltd.
+
+//  shared_ptr.hpp
+//  Copyright (C) 1998, 1999 Greg Colvin and Beman Dawes.
+//  Copyright (C) 2001, 2002, 2003 Peter Dimov
+
+//  weak_ptr.hpp
+//  Copyright (C) 2001, 2002, 2003 Peter Dimov
+
+//  enable_shared_from_this.hpp
+//  Copyright (C) 2002 Peter Dimov
+
+// Distributed under the Boost Software License, Version 1.0. (See
+// accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+/** @file bits/shared_ptr_base.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{memory}
+ */
+
+#ifndef _SHARED_PTR_BASE_H
+#define _SHARED_PTR_BASE_H 1
+
+#include <typeinfo>
+#include <bits/allocated_ptr.h>
+#include <bits/allocator.h>
+#include <bits/exception_defines.h>
+#include <bits/functional_hash.h>
+#include <bits/refwrap.h>
+#include <bits/stl_function.h>  // std::less
+#include <bits/unique_ptr.h>
+#include <ext/aligned_buffer.h>
+#include <ext/atomicity.h>
+#include <ext/concurrence.h>
+#if __cplusplus >= 202002L
+# include <bit>          // __bit_floor
+# include <compare>
+# include <bits/align.h> // std::align
+# include <bits/stl_uninitialized.h>
+#endif
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+#if _GLIBCXX_USE_DEPRECATED
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+  template<typename> class auto_ptr;
+#pragma GCC diagnostic pop
+#endif
+
+ /**
+   *  @brief  Exception possibly thrown by @c shared_ptr.
+   *  @ingroup exceptions
+   */
+  class bad_weak_ptr : public std::exception
+  {
+  public:
+    virtual char const* what() const noexcept;
+
+    virtual ~bad_weak_ptr() noexcept;
+  };
+
+  // Substitute for bad_weak_ptr object in the case of -fno-exceptions.
+  inline void
+  __throw_bad_weak_ptr()
+  { _GLIBCXX_THROW_OR_ABORT(bad_weak_ptr()); }
+
+  using __gnu_cxx::_Lock_policy;
+  using __gnu_cxx::__default_lock_policy;
+  using __gnu_cxx::_S_single;
+  using __gnu_cxx::_S_mutex;
+  using __gnu_cxx::_S_atomic;
+
+  // Empty helper class except when the template argument is _S_mutex.
+  template<_Lock_policy _Lp>
+    class _Mutex_base
+    {
+    protected:
+      // The atomic policy uses fully-fenced builtins, single doesn't care.
+      enum { _S_need_barriers = 0 };
+    };
+
+  template<>
+    class _Mutex_base<_S_mutex>
+    : public __gnu_cxx::__mutex
+    {
+    protected:
+      // This policy is used when atomic builtins are not available.
+      // The replacement atomic operations might not have the necessary
+      // memory barriers.
+      enum { _S_need_barriers = 1 };
+    };
+
+  template<_Lock_policy _Lp = __default_lock_policy>
+    class _Sp_counted_base
+    : public _Mutex_base<_Lp>
+    {
+    public:
+      _Sp_counted_base() noexcept
+      : _M_use_count(1), _M_weak_count(1) { }
+
+      virtual
+      ~_Sp_counted_base() noexcept
+      { }
+
+      // Called when _M_use_count drops to zero, to release the resources
+      // managed by *this.
+      virtual void
+      _M_dispose() noexcept = 0;
+
+      // Called when _M_weak_count drops to zero.
+      virtual void
+      _M_destroy() noexcept
+      { delete this; }
+
+      virtual void*
+      _M_get_deleter(const std::type_info&) noexcept = 0;
+
+      // Increment the use count (used when the count is greater than zero).
+      void
+      _M_add_ref_copy()
+      { __gnu_cxx::__atomic_add_dispatch(&_M_use_count, 1); }
+
+      // Increment the use count if it is non-zero, throw otherwise.
+      void
+      _M_add_ref_lock()
+      {
+	if (!_M_add_ref_lock_nothrow())
+	  __throw_bad_weak_ptr();
+      }
+
+      // Increment the use count if it is non-zero.
+      bool
+      _M_add_ref_lock_nothrow() noexcept;
+
+      // Decrement the use count.
+      void
+      _M_release() noexcept;
+
+      // Called by _M_release() when the use count reaches zero.
+      void
+      _M_release_last_use() noexcept
+      {
+	_GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&_M_use_count);
+	_M_dispose();
+	// There must be a memory barrier between dispose() and destroy()
+	// to ensure that the effects of dispose() are observed in the
+	// thread that runs destroy().
+	// See http://gcc.gnu.org/ml/libstdc++/2005-11/msg00136.html
+	if (_Mutex_base<_Lp>::_S_need_barriers)
+	  {
+	    __atomic_thread_fence (__ATOMIC_ACQ_REL);
+	  }
+
+	// Be race-detector-friendly.  For more info see bits/c++config.
+	_GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&_M_weak_count);
+	if (__gnu_cxx::__exchange_and_add_dispatch(&_M_weak_count,
+						   -1) == 1)
+	  {
+	    _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&_M_weak_count);
+	    _M_destroy();
+	  }
+      }
+
+      // As above, but 'noinline' to reduce code size on the cold path.
+      __attribute__((__noinline__))
+      void
+      _M_release_last_use_cold() noexcept
+      { _M_release_last_use(); }
+
+      // Increment the weak count.
+      void
+      _M_weak_add_ref() noexcept
+      { __gnu_cxx::__atomic_add_dispatch(&_M_weak_count, 1); }
+
+      // Decrement the weak count.
+      void
+      _M_weak_release() noexcept
+      {
+        // Be race-detector-friendly. For more info see bits/c++config.
+        _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&_M_weak_count);
+	if (__gnu_cxx::__exchange_and_add_dispatch(&_M_weak_count, -1) == 1)
+	  {
+            _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&_M_weak_count);
+	    if (_Mutex_base<_Lp>::_S_need_barriers)
+	      {
+	        // See _M_release(),
+	        // destroy() must observe results of dispose()
+		__atomic_thread_fence (__ATOMIC_ACQ_REL);
+	      }
+	    _M_destroy();
+	  }
+      }
+
+      long
+      _M_get_use_count() const noexcept
+      {
+        // No memory barrier is used here so there is no synchronization
+        // with other threads.
+        return __atomic_load_n(&_M_use_count, __ATOMIC_RELAXED);
+      }
+
+    private:
+      _Sp_counted_base(_Sp_counted_base const&) = delete;
+      _Sp_counted_base& operator=(_Sp_counted_base const&) = delete;
+
+      _Atomic_word  _M_use_count;     // #shared
+      _Atomic_word  _M_weak_count;    // #weak + (#shared != 0)
+    };
+
+  template<>
+    inline bool
+    _Sp_counted_base<_S_single>::
+    _M_add_ref_lock_nothrow() noexcept
+    {
+      if (_M_use_count == 0)
+	return false;
+      ++_M_use_count;
+      return true;
+    }
+
+  template<>
+    inline bool
+    _Sp_counted_base<_S_mutex>::
+    _M_add_ref_lock_nothrow() noexcept
+    {
+      __gnu_cxx::__scoped_lock sentry(*this);
+      if (__gnu_cxx::__exchange_and_add_dispatch(&_M_use_count, 1) == 0)
+	{
+	  _M_use_count = 0;
+	  return false;
+	}
+      return true;
+    }
+
+  template<>
+    inline bool
+    _Sp_counted_base<_S_atomic>::
+    _M_add_ref_lock_nothrow() noexcept
+    {
+      // Perform lock-free add-if-not-zero operation.
+      _Atomic_word __count = _M_get_use_count();
+      do
+	{
+	  if (__count == 0)
+	    return false;
+	  // Replace the current counter value with the old value + 1, as
+	  // long as it's not changed meanwhile.
+	}
+      while (!__atomic_compare_exchange_n(&_M_use_count, &__count, __count + 1,
+					  true, __ATOMIC_ACQ_REL,
+					  __ATOMIC_RELAXED));
+      return true;
+    }
+
+  template<>
+    inline void
+    _Sp_counted_base<_S_single>::_M_add_ref_copy()
+    { ++_M_use_count; }
+
+  template<>
+    inline void
+    _Sp_counted_base<_S_single>::_M_release() noexcept
+    {
+      if (--_M_use_count == 0)
+        {
+          _M_dispose();
+          if (--_M_weak_count == 0)
+            _M_destroy();
+        }
+    }
+
+  template<>
+    inline void
+    _Sp_counted_base<_S_mutex>::_M_release() noexcept
+    {
+      // Be race-detector-friendly.  For more info see bits/c++config.
+      _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&_M_use_count);
+      if (__gnu_cxx::__exchange_and_add_dispatch(&_M_use_count, -1) == 1)
+	{
+	  _M_release_last_use();
+	}
+    }
+
+  template<>
+    inline void
+    _Sp_counted_base<_S_atomic>::_M_release() noexcept
+    {
+      _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&_M_use_count);
+#if ! _GLIBCXX_TSAN
+      constexpr bool __lock_free
+	= __atomic_always_lock_free(sizeof(long long), 0)
+	&& __atomic_always_lock_free(sizeof(_Atomic_word), 0);
+      constexpr bool __double_word
+	= sizeof(long long) == 2 * sizeof(_Atomic_word);
+      // The ref-count members follow the vptr, so are aligned to
+      // alignof(void*).
+      constexpr bool __aligned = __alignof(long long) <= alignof(void*);
+      if _GLIBCXX17_CONSTEXPR (__lock_free && __double_word && __aligned)
+	{
+	  constexpr int __wordbits = __CHAR_BIT__ * sizeof(_Atomic_word);
+	  constexpr int __shiftbits = __double_word ? __wordbits : 0;
+	  constexpr long long __unique_ref = 1LL + (1LL << __shiftbits);
+	  auto __both_counts = reinterpret_cast<long long*>(&_M_use_count);
+
+	  _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&_M_weak_count);
+	  if (__atomic_load_n(__both_counts, __ATOMIC_ACQUIRE) == __unique_ref)
+	    {
+	      // Both counts are 1, so there are no weak references and
+	      // we are releasing the last strong reference. No other
+	      // threads can observe the effects of this _M_release()
+	      // call (e.g. calling use_count()) without a data race.
+	      _M_weak_count = _M_use_count = 0;
+	      _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&_M_use_count);
+	      _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&_M_weak_count);
+	      _M_dispose();
+	      _M_destroy();
+	      return;
+	    }
+	  if (__gnu_cxx::__exchange_and_add_dispatch(&_M_use_count, -1) == 1)
+	    [[__unlikely__]]
+	    {
+	      _M_release_last_use_cold();
+	      return;
+	    }
+	}
+      else
+#endif
+      if (__gnu_cxx::__exchange_and_add_dispatch(&_M_use_count, -1) == 1)
+	{
+	  _M_release_last_use();
+	}
+    }
+
+  template<>
+    inline void
+    _Sp_counted_base<_S_single>::_M_weak_add_ref() noexcept
+    { ++_M_weak_count; }
+
+  template<>
+    inline void
+    _Sp_counted_base<_S_single>::_M_weak_release() noexcept
+    {
+      if (--_M_weak_count == 0)
+        _M_destroy();
+    }
+
+  template<>
+    inline long
+    _Sp_counted_base<_S_single>::_M_get_use_count() const noexcept
+    { return _M_use_count; }
+
+
+  // Forward declarations.
+  template<typename _Tp, _Lock_policy _Lp = __default_lock_policy>
+    class __shared_ptr;
+
+  template<typename _Tp, _Lock_policy _Lp = __default_lock_policy>
+    class __weak_ptr;
+
+  template<typename _Tp, _Lock_policy _Lp = __default_lock_policy>
+    class __enable_shared_from_this;
+
+  template<typename _Tp>
+    class shared_ptr;
+
+  template<typename _Tp>
+    class weak_ptr;
+
+  template<typename _Tp>
+    struct owner_less;
+
+  template<typename _Tp>
+    class enable_shared_from_this;
+
+  template<_Lock_policy _Lp = __default_lock_policy>
+    class __weak_count;
+
+  template<_Lock_policy _Lp = __default_lock_policy>
+    class __shared_count;
+
+#if __cplusplus >= 202002L
+  template<typename>
+    class _Sp_atomic;
+#endif
+
+  // Counted ptr with no deleter or allocator support
+  template<typename _Ptr, _Lock_policy _Lp>
+    class _Sp_counted_ptr final : public _Sp_counted_base<_Lp>
+    {
+    public:
+      explicit
+      _Sp_counted_ptr(_Ptr __p) noexcept
+      : _M_ptr(__p) { }
+
+      virtual void
+      _M_dispose() noexcept
+      { delete _M_ptr; }
+
+      virtual void
+      _M_destroy() noexcept
+      { delete this; }
+
+      virtual void*
+      _M_get_deleter(const std::type_info&) noexcept
+      { return nullptr; }
+
+      _Sp_counted_ptr(const _Sp_counted_ptr&) = delete;
+      _Sp_counted_ptr& operator=(const _Sp_counted_ptr&) = delete;
+
+    private:
+      _Ptr             _M_ptr;
+    };
+
+  template<>
+    inline void
+    _Sp_counted_ptr<nullptr_t, _S_single>::_M_dispose() noexcept { }
+
+  template<>
+    inline void
+    _Sp_counted_ptr<nullptr_t, _S_mutex>::_M_dispose() noexcept { }
+
+  template<>
+    inline void
+    _Sp_counted_ptr<nullptr_t, _S_atomic>::_M_dispose() noexcept { }
+
+  // FIXME: once __has_cpp_attribute(__no_unique_address__)) is true for
+  // all supported compilers we can greatly simplify _Sp_ebo_helper.
+  // N.B. unconditionally applying the attribute could change layout for
+  // final types, which currently cannot use EBO so have a unique address.
+
+  template<int _Nm, typename _Tp,
+	   bool __use_ebo = !__is_final(_Tp) && __is_empty(_Tp)>
+    struct _Sp_ebo_helper;
+
+  /// Specialization using EBO.
+  template<int _Nm, typename _Tp>
+    struct _Sp_ebo_helper<_Nm, _Tp, true> : private _Tp
+    {
+      explicit _Sp_ebo_helper(const _Tp& __tp) : _Tp(__tp) { }
+      explicit _Sp_ebo_helper(_Tp&& __tp) : _Tp(std::move(__tp)) { }
+
+      static _Tp&
+      _S_get(_Sp_ebo_helper& __eboh) { return static_cast<_Tp&>(__eboh); }
+    };
+
+  /// Specialization not using EBO.
+  template<int _Nm, typename _Tp>
+    struct _Sp_ebo_helper<_Nm, _Tp, false>
+    {
+      explicit _Sp_ebo_helper(const _Tp& __tp) : _M_tp(__tp) { }
+      explicit _Sp_ebo_helper(_Tp&& __tp) : _M_tp(std::move(__tp)) { }
+
+      static _Tp&
+      _S_get(_Sp_ebo_helper& __eboh)
+      { return __eboh._M_tp; }
+
+    private:
+      _Tp _M_tp;
+    };
+
+  // Support for custom deleter and/or allocator
+  template<typename _Ptr, typename _Deleter, typename _Alloc, _Lock_policy _Lp>
+    class _Sp_counted_deleter final : public _Sp_counted_base<_Lp>
+    {
+      class _Impl : _Sp_ebo_helper<0, _Deleter>, _Sp_ebo_helper<1, _Alloc>
+      {
+	typedef _Sp_ebo_helper<0, _Deleter>	_Del_base;
+	typedef _Sp_ebo_helper<1, _Alloc>	_Alloc_base;
+
+      public:
+	_Impl(_Ptr __p, _Deleter __d, const _Alloc& __a) noexcept
+	: _Del_base(std::move(__d)), _Alloc_base(__a), _M_ptr(__p)
+	{ }
+
+	_Deleter& _M_del() noexcept { return _Del_base::_S_get(*this); }
+	_Alloc& _M_alloc() noexcept { return _Alloc_base::_S_get(*this); }
+
+	_Ptr _M_ptr;
+      };
+
+    public:
+      using __allocator_type = __alloc_rebind<_Alloc, _Sp_counted_deleter>;
+
+      // __d(__p) must not throw.
+      _Sp_counted_deleter(_Ptr __p, _Deleter __d) noexcept
+      : _M_impl(__p, std::move(__d), _Alloc()) { }
+
+      // __d(__p) must not throw.
+      _Sp_counted_deleter(_Ptr __p, _Deleter __d, const _Alloc& __a) noexcept
+      : _M_impl(__p, std::move(__d), __a) { }
+
+      ~_Sp_counted_deleter() noexcept { }
+
+      virtual void
+      _M_dispose() noexcept
+      { _M_impl._M_del()(_M_impl._M_ptr); }
+
+      virtual void
+      _M_destroy() noexcept
+      {
+	__allocator_type __a(_M_impl._M_alloc());
+	__allocated_ptr<__allocator_type> __guard_ptr{ __a, this };
+	this->~_Sp_counted_deleter();
+      }
+
+      virtual void*
+      _M_get_deleter(const type_info& __ti [[__gnu__::__unused__]]) noexcept
+      {
+#if __cpp_rtti
+	// _GLIBCXX_RESOLVE_LIB_DEFECTS
+	// 2400. shared_ptr's get_deleter() should use addressof()
+        return __ti == typeid(_Deleter)
+	  ? std::__addressof(_M_impl._M_del())
+	  : nullptr;
+#else
+        return nullptr;
+#endif
+      }
+
+    private:
+      _Impl _M_impl;
+    };
+
+  // helpers for make_shared / allocate_shared
+
+  struct _Sp_make_shared_tag
+  {
+  private:
+    template<typename _Tp, typename _Alloc, _Lock_policy _Lp>
+      friend class _Sp_counted_ptr_inplace;
+
+    static const type_info&
+    _S_ti() noexcept _GLIBCXX_VISIBILITY(default)
+    {
+      alignas(type_info) static constexpr char __tag[sizeof(type_info)] = { };
+      return reinterpret_cast<const type_info&>(__tag);
+    }
+
+    static bool _S_eq(const type_info&) noexcept;
+  };
+
+  template<typename _Alloc>
+    struct _Sp_alloc_shared_tag
+    {
+      const _Alloc& _M_a;
+    };
+
+  template<typename _Tp, typename _Alloc, _Lock_policy _Lp>
+    class _Sp_counted_ptr_inplace final : public _Sp_counted_base<_Lp>
+    {
+      class _Impl : _Sp_ebo_helper<0, _Alloc>
+      {
+	typedef _Sp_ebo_helper<0, _Alloc>	_A_base;
+
+      public:
+	explicit _Impl(_Alloc __a) noexcept : _A_base(__a) { }
+
+	_Alloc& _M_alloc() noexcept { return _A_base::_S_get(*this); }
+
+	__gnu_cxx::__aligned_buffer<_Tp> _M_storage;
+      };
+
+    public:
+      using __allocator_type = __alloc_rebind<_Alloc, _Sp_counted_ptr_inplace>;
+
+      // Alloc parameter is not a reference so doesn't alias anything in __args
+      template<typename... _Args>
+	_Sp_counted_ptr_inplace(_Alloc __a, _Args&&... __args)
+	: _M_impl(__a)
+	{
+	  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+	  // 2070.  allocate_shared should use allocator_traits<A>::construct
+	  allocator_traits<_Alloc>::construct(__a, _M_ptr(),
+	      std::forward<_Args>(__args)...); // might throw
+	}
+
+      ~_Sp_counted_ptr_inplace() noexcept { }
+
+      virtual void
+      _M_dispose() noexcept
+      {
+	allocator_traits<_Alloc>::destroy(_M_impl._M_alloc(), _M_ptr());
+      }
+
+      // Override because the allocator needs to know the dynamic type
+      virtual void
+      _M_destroy() noexcept
+      {
+	__allocator_type __a(_M_impl._M_alloc());
+	__allocated_ptr<__allocator_type> __guard_ptr{ __a, this };
+	this->~_Sp_counted_ptr_inplace();
+      }
+
+    private:
+      friend class __shared_count<_Lp>; // To be able to call _M_ptr().
+
+      // No longer used, but code compiled against old libstdc++ headers
+      // might still call it from __shared_ptr ctor to get the pointer out.
+      virtual void*
+      _M_get_deleter(const std::type_info& __ti) noexcept override
+      {
+	auto __ptr = const_cast<typename remove_cv<_Tp>::type*>(_M_ptr());
+	// Check for the fake type_info first, so we don't try to access it
+	// as a real type_info object. Otherwise, check if it's the real
+	// type_info for this class. With RTTI enabled we can check directly,
+	// or call a library function to do it.
+	if (&__ti == &_Sp_make_shared_tag::_S_ti()
+	    ||
+#if __cpp_rtti
+	    __ti == typeid(_Sp_make_shared_tag)
+#else
+	    _Sp_make_shared_tag::_S_eq(__ti)
+#endif
+	   )
+	  return __ptr;
+	return nullptr;
+      }
+
+      _Tp* _M_ptr() noexcept { return _M_impl._M_storage._M_ptr(); }
+
+      _Impl _M_impl;
+    };
+
+#if __cplusplus >= 202002L
+# define __cpp_lib_smart_ptr_for_overwrite 202002L
+  struct _Sp_overwrite_tag { };
+
+  // Partial specialization used for make_shared_for_overwrite<non-array>().
+  // This partial specialization is used when the allocator's value type
+  // is the special _Sp_overwrite_tag type.
+#if __cpp_concepts
+  template<typename _Tp, typename _Alloc, _Lock_policy _Lp>
+    requires is_same_v<typename _Alloc::value_type, _Sp_overwrite_tag>
+    class _Sp_counted_ptr_inplace<_Tp, _Alloc, _Lp> final
+#else
+  template<typename _Tp, template<typename> class _Alloc, _Lock_policy _Lp>
+    class _Sp_counted_ptr_inplace<_Tp, _Alloc<_Sp_overwrite_tag>, _Lp> final
+#endif
+    : public _Sp_counted_base<_Lp>
+    {
+      [[no_unique_address]] _Alloc _M_alloc;
+
+      union {
+	_Tp _M_obj;
+	char _M_unused;
+      };
+
+      friend class __shared_count<_Lp>; // To be able to call _M_ptr().
+
+      _Tp* _M_ptr() noexcept { return std::__addressof(_M_obj); }
+
+    public:
+      using __allocator_type = __alloc_rebind<_Alloc, _Sp_counted_ptr_inplace>;
+
+      _Sp_counted_ptr_inplace(const _Alloc& __a)
+      : _M_alloc(__a)
+      {
+	::new((void*)_M_ptr()) _Tp; // default-initialized, for overwrite.
+      }
+
+      ~_Sp_counted_ptr_inplace() noexcept { }
+
+      virtual void
+      _M_dispose() noexcept
+      {
+	_M_obj.~_Tp();
+      }
+
+      // Override because the allocator needs to know the dynamic type
+      virtual void
+      _M_destroy() noexcept
+      {
+	using pointer = typename allocator_traits<__allocator_type>::pointer;
+	__allocator_type __a(_M_alloc);
+	auto __p = pointer_traits<pointer>::pointer_to(*this);
+	__allocated_ptr<__allocator_type> __guard_ptr{ __a, __p };
+	this->~_Sp_counted_ptr_inplace();
+      }
+
+      void*
+      _M_get_deleter(const std::type_info&) noexcept override
+      { return nullptr; }
+    };
+#endif // C++20
+
+#if __cplusplus <= 201703L
+# define __cpp_lib_shared_ptr_arrays 201611L
+#else
+# define __cpp_lib_shared_ptr_arrays 201707L
+
+  struct _Sp_overwrite_tag;
+
+  // For make_shared<T[]>, make_shared<T[N]>, allocate_shared<T[]> etc.
+  template<typename _Alloc>
+    struct _Sp_counted_array_base
+    {
+      [[no_unique_address]] _Alloc _M_alloc{};
+      size_t _M_n = 0;
+      bool _M_overwrite = false;
+
+      typename allocator_traits<_Alloc>::pointer
+      _M_alloc_array(size_t __tail)
+      {
+	return allocator_traits<_Alloc>::allocate(_M_alloc, _M_n + __tail);
+      }
+
+      void
+      _M_dealloc_array(typename allocator_traits<_Alloc>::pointer __p,
+		       size_t __tail)
+      {
+	allocator_traits<_Alloc>::deallocate(_M_alloc, __p, _M_n + __tail);
+      }
+
+      // Init the array elements
+      template<typename _Init>
+	void
+	_M_init(typename allocator_traits<_Alloc>::value_type* __p,
+		_Init __init)
+	{
+	  using _Tp = remove_pointer_t<_Init>;
+	  using _Up = typename allocator_traits<_Alloc>::value_type;
+
+	  if constexpr (is_same_v<_Init, _Sp_overwrite_tag>)
+	    {
+	      std::uninitialized_default_construct_n(__p, _M_n);
+	      _M_overwrite = true;
+	    }
+	  else if (__init == nullptr)
+	    std::__uninitialized_default_n_a(__p, _M_n, _M_alloc);
+	  else if constexpr (!is_array_v<_Tp>)
+	    std::__uninitialized_fill_n_a(__p, _M_n, *__init, _M_alloc);
+	  else
+	    {
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wunused-local-typedefs"
+	      struct _Iter
+	      {
+		using value_type = _Up;
+		using difference_type = ptrdiff_t;
+		using pointer = const _Up*;
+		using reference = const _Up&;
+		using iterator_category = forward_iterator_tag;
+
+		const _Up* _M_p;
+		size_t _M_len;
+		size_t _M_pos;
+
+		_Iter& operator++() { ++_M_pos; return *this; }
+		_Iter operator++(int) { auto __i(*this); ++_M_pos; return __i; }
+
+		reference operator*() const { return _M_p[_M_pos % _M_len]; }
+		pointer operator->() const { return _M_p + (_M_pos % _M_len); }
+
+		bool operator==(const _Iter& __i) const
+		{ return _M_pos == __i._M_pos; }
+	      };
+#pragma GCC diagnostic pop
+
+	      _Iter __first{_S_first_elem(__init), sizeof(_Tp) / sizeof(_Up)};
+	      _Iter __last = __first;
+	      __last._M_pos = _M_n;
+	      std::__uninitialized_copy_a(__first, __last, __p, _M_alloc);
+	    }
+	}
+
+    protected:
+      // Destroy the array elements
+      void
+      _M_dispose_array(typename allocator_traits<_Alloc>::value_type* __p)
+      {
+	if (_M_overwrite)
+	  std::destroy_n(__p, _M_n);
+	else
+	  {
+	    size_t __n = _M_n;
+	    while (__n--)
+	      allocator_traits<_Alloc>::destroy(_M_alloc, __p + __n);
+	  }
+      }
+
+    private:
+      template<typename _Tp>
+	static _Tp*
+	_S_first_elem(_Tp* __p) { return __p; }
+
+      template<typename _Tp, size_t _Nm>
+	static auto
+	_S_first_elem(_Tp (*__p)[_Nm]) { return _S_first_elem(*__p); }
+    };
+
+  // Control block for make_shared<T[]>, make_shared<T[N]> etc. that will be
+  // placed into unused memory at the end of the array.
+  template<typename _Alloc, _Lock_policy _Lp>
+    class _Sp_counted_array final
+    : public _Sp_counted_base<_Lp>, _Sp_counted_array_base<_Alloc>
+    {
+      using pointer = typename allocator_traits<_Alloc>::pointer;
+
+      pointer _M_alloc_ptr;
+
+      auto _M_ptr() const noexcept { return std::to_address(_M_alloc_ptr); }
+
+      friend class __shared_count<_Lp>; // To be able to call _M_ptr().
+
+    public:
+      _Sp_counted_array(const _Sp_counted_array_base<_Alloc>& __a,
+			pointer __p) noexcept
+      : _Sp_counted_array_base<_Alloc>(__a), _M_alloc_ptr(__p)
+      { }
+
+      ~_Sp_counted_array() = default;
+
+      virtual void
+      _M_dispose() noexcept
+      {
+	if (this->_M_n)
+	  this->_M_dispose_array(_M_ptr());
+      }
+
+      // Override because the allocator needs to know the dynamic type
+      virtual void
+      _M_destroy() noexcept
+      {
+	_Sp_counted_array_base<_Alloc> __a = *this;
+	pointer __p = _M_alloc_ptr;
+	this->~_Sp_counted_array();
+	__a._M_dealloc_array(__p, _S_tail());
+      }
+
+      // Returns the number of additional array elements that must be
+      // allocated in order to store a _Sp_counted_array at the end.
+      static constexpr size_t
+      _S_tail()
+      {
+	// The array elemenent type.
+	using _Tp = typename allocator_traits<_Alloc>::value_type;
+
+	// The space needed to store a _Sp_counted_array object.
+	size_t __bytes = sizeof(_Sp_counted_array);
+
+	// Add any padding needed for manual alignment within the buffer.
+	if constexpr (alignof(_Tp) < alignof(_Sp_counted_array))
+	  __bytes += alignof(_Sp_counted_array) - alignof(_Tp);
+
+	return (__bytes + sizeof(_Tp) - 1) / sizeof(_Tp);
+      }
+
+      void*
+      _M_get_deleter(const std::type_info&) noexcept override
+      { return nullptr; }
+    };
+#endif // C++20
+
+  // The default deleter for shared_ptr<T[]> and shared_ptr<T[N]>.
+  struct __sp_array_delete
+  {
+    template<typename _Yp>
+      void operator()(_Yp* __p) const { delete[] __p; }
+  };
+
+  template<_Lock_policy _Lp>
+    class __shared_count
+    {
+      // Prevent _Sp_alloc_shared_tag from matching the shared_ptr(P, D) ctor.
+      template<typename _Tp>
+	struct __not_alloc_shared_tag { using type = void; };
+
+      template<typename _Tp>
+	struct __not_alloc_shared_tag<_Sp_alloc_shared_tag<_Tp>> { };
+
+#if __cpp_lib_shared_ptr_arrays >= 201707L
+      template<typename _Alloc>
+	struct __not_alloc_shared_tag<_Sp_counted_array_base<_Alloc>> { };
+#endif
+
+    public:
+      constexpr __shared_count() noexcept : _M_pi(0)
+      { }
+
+      template<typename _Ptr>
+        explicit
+	__shared_count(_Ptr __p) : _M_pi(0)
+	{
+	  __try
+	    {
+	      _M_pi = new _Sp_counted_ptr<_Ptr, _Lp>(__p);
+	    }
+	  __catch(...)
+	    {
+	      delete __p;
+	      __throw_exception_again;
+	    }
+	}
+
+      template<typename _Ptr>
+	__shared_count(_Ptr __p, /* is_array = */ false_type)
+	: __shared_count(__p)
+	{ }
+
+      template<typename _Ptr>
+	__shared_count(_Ptr __p, /* is_array = */ true_type)
+	: __shared_count(__p, __sp_array_delete{}, allocator<void>())
+	{ }
+
+      template<typename _Ptr, typename _Deleter,
+	       typename = typename __not_alloc_shared_tag<_Deleter>::type>
+	__shared_count(_Ptr __p, _Deleter __d)
+	: __shared_count(__p, std::move(__d), allocator<void>())
+	{ }
+
+      template<typename _Ptr, typename _Deleter, typename _Alloc,
+	       typename = typename __not_alloc_shared_tag<_Deleter>::type>
+	__shared_count(_Ptr __p, _Deleter __d, _Alloc __a) : _M_pi(0)
+	{
+	  typedef _Sp_counted_deleter<_Ptr, _Deleter, _Alloc, _Lp> _Sp_cd_type;
+	  __try
+	    {
+	      typename _Sp_cd_type::__allocator_type __a2(__a);
+	      auto __guard = std::__allocate_guarded(__a2);
+	      _Sp_cd_type* __mem = __guard.get();
+	      ::new (__mem) _Sp_cd_type(__p, std::move(__d), std::move(__a));
+	      _M_pi = __mem;
+	      __guard = nullptr;
+	    }
+	  __catch(...)
+	    {
+	      __d(__p); // Call _Deleter on __p.
+	      __throw_exception_again;
+	    }
+	}
+
+      template<typename _Tp, typename _Alloc, typename... _Args>
+	__shared_count(_Tp*& __p, _Sp_alloc_shared_tag<_Alloc> __a,
+		       _Args&&... __args)
+	{
+	  typedef _Sp_counted_ptr_inplace<_Tp, _Alloc, _Lp> _Sp_cp_type;
+	  typename _Sp_cp_type::__allocator_type __a2(__a._M_a);
+	  auto __guard = std::__allocate_guarded(__a2);
+	  _Sp_cp_type* __mem = __guard.get();
+	  auto __pi = ::new (__mem)
+	    _Sp_cp_type(__a._M_a, std::forward<_Args>(__args)...);
+	  __guard = nullptr;
+	  _M_pi = __pi;
+	  __p = __pi->_M_ptr();
+	}
+
+#if __cpp_lib_shared_ptr_arrays >= 201707L
+      template<typename _Tp, typename _Alloc, typename _Init>
+	__shared_count(_Tp*& __p, const _Sp_counted_array_base<_Alloc>& __a,
+		       _Init __init)
+	{
+	  using _Up = remove_all_extents_t<_Tp>;
+	  static_assert(is_same_v<_Up, typename _Alloc::value_type>);
+
+	  using _Sp_ca_type = _Sp_counted_array<_Alloc, _Lp>;
+	  const size_t __tail = _Sp_ca_type::_S_tail();
+
+	  struct _Guarded_ptr : _Sp_counted_array_base<_Alloc>
+	  {
+	    typename allocator_traits<_Alloc>::pointer _M_ptr;
+
+	    _Guarded_ptr(_Sp_counted_array_base<_Alloc> __a)
+	    : _Sp_counted_array_base<_Alloc>(__a),
+	      _M_ptr(this->_M_alloc_array(_Sp_ca_type::_S_tail()))
+	    { }
+
+	    ~_Guarded_ptr()
+	    {
+	      if (_M_ptr)
+		this->_M_dealloc_array(_M_ptr, _Sp_ca_type::_S_tail());
+	    }
+	  };
+
+	  _Guarded_ptr __guard{__a};
+	  _Up* const __raw = std::to_address(__guard._M_ptr);
+	  __guard._M_init(__raw, __init); // might throw
+
+	  void* __c = __raw + __a._M_n;
+	  if constexpr (alignof(_Up) < alignof(_Sp_ca_type))
+	    {
+	      size_t __space = sizeof(_Up) * __tail;
+	      __c = std::align(alignof(_Sp_ca_type), sizeof(_Sp_ca_type),
+			       __c, __space);
+	    }
+	  auto __pi = ::new(__c) _Sp_ca_type(__guard, __guard._M_ptr);
+	  __guard._M_ptr = nullptr;
+	  _M_pi = __pi;
+	  __p = reinterpret_cast<_Tp*>(__raw);
+	}
+#endif
+
+#if _GLIBCXX_USE_DEPRECATED
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+      // Special case for auto_ptr<_Tp> to provide the strong guarantee.
+      template<typename _Tp>
+        explicit
+	__shared_count(std::auto_ptr<_Tp>&& __r);
+#pragma GCC diagnostic pop
+#endif
+
+      // Special case for unique_ptr<_Tp,_Del> to provide the strong guarantee.
+      template<typename _Tp, typename _Del>
+        explicit
+	__shared_count(std::unique_ptr<_Tp, _Del>&& __r) : _M_pi(0)
+	{
+	  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+	  // 2415. Inconsistency between unique_ptr and shared_ptr
+	  if (__r.get() == nullptr)
+	    return;
+
+	  using _Ptr = typename unique_ptr<_Tp, _Del>::pointer;
+	  using _Del2 = __conditional_t<is_reference<_Del>::value,
+	      reference_wrapper<typename remove_reference<_Del>::type>,
+	      _Del>;
+	  using _Sp_cd_type
+	    = _Sp_counted_deleter<_Ptr, _Del2, allocator<void>, _Lp>;
+	  using _Alloc = allocator<_Sp_cd_type>;
+	  using _Alloc_traits = allocator_traits<_Alloc>;
+	  _Alloc __a;
+	  _Sp_cd_type* __mem = _Alloc_traits::allocate(__a, 1);
+	  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+	  // 3548. shared_ptr construction from unique_ptr should move
+	  // (not copy) the deleter
+	  _Alloc_traits::construct(__a, __mem, __r.release(),
+				   std::forward<_Del>(__r.get_deleter()));
+	  _M_pi = __mem;
+	}
+
+      // Throw bad_weak_ptr when __r._M_get_use_count() == 0.
+      explicit __shared_count(const __weak_count<_Lp>& __r);
+
+      // Does not throw if __r._M_get_use_count() == 0, caller must check.
+      explicit
+      __shared_count(const __weak_count<_Lp>& __r, std::nothrow_t) noexcept;
+
+      ~__shared_count() noexcept
+      {
+	if (_M_pi != nullptr)
+	  _M_pi->_M_release();
+      }
+
+      __shared_count(const __shared_count& __r) noexcept
+      : _M_pi(__r._M_pi)
+      {
+	if (_M_pi != nullptr)
+	  _M_pi->_M_add_ref_copy();
+      }
+
+      __shared_count&
+      operator=(const __shared_count& __r) noexcept
+      {
+	_Sp_counted_base<_Lp>* __tmp = __r._M_pi;
+	if (__tmp != _M_pi)
+	  {
+	    if (__tmp != nullptr)
+	      __tmp->_M_add_ref_copy();
+	    if (_M_pi != nullptr)
+	      _M_pi->_M_release();
+	    _M_pi = __tmp;
+	  }
+	return *this;
+      }
+
+      void
+      _M_swap(__shared_count& __r) noexcept
+      {
+	_Sp_counted_base<_Lp>* __tmp = __r._M_pi;
+	__r._M_pi = _M_pi;
+	_M_pi = __tmp;
+      }
+
+      long
+      _M_get_use_count() const noexcept
+      { return _M_pi ? _M_pi->_M_get_use_count() : 0; }
+
+      bool
+      _M_unique() const noexcept
+      { return this->_M_get_use_count() == 1; }
+
+      void*
+      _M_get_deleter(const std::type_info& __ti) const noexcept
+      { return _M_pi ? _M_pi->_M_get_deleter(__ti) : nullptr; }
+
+      bool
+      _M_less(const __shared_count& __rhs) const noexcept
+      { return std::less<_Sp_counted_base<_Lp>*>()(this->_M_pi, __rhs._M_pi); }
+
+      bool
+      _M_less(const __weak_count<_Lp>& __rhs) const noexcept
+      { return std::less<_Sp_counted_base<_Lp>*>()(this->_M_pi, __rhs._M_pi); }
+
+      // Friend function injected into enclosing namespace and found by ADL
+      friend inline bool
+      operator==(const __shared_count& __a, const __shared_count& __b) noexcept
+      { return __a._M_pi == __b._M_pi; }
+
+    private:
+      friend class __weak_count<_Lp>;
+#if __cplusplus >= 202002L
+      template<typename> friend class _Sp_atomic;
+#endif
+
+      _Sp_counted_base<_Lp>*  _M_pi;
+    };
+
+
+  template<_Lock_policy _Lp>
+    class __weak_count
+    {
+    public:
+      constexpr __weak_count() noexcept : _M_pi(nullptr)
+      { }
+
+      __weak_count(const __shared_count<_Lp>& __r) noexcept
+      : _M_pi(__r._M_pi)
+      {
+	if (_M_pi != nullptr)
+	  _M_pi->_M_weak_add_ref();
+      }
+
+      __weak_count(const __weak_count& __r) noexcept
+      : _M_pi(__r._M_pi)
+      {
+	if (_M_pi != nullptr)
+	  _M_pi->_M_weak_add_ref();
+      }
+
+      __weak_count(__weak_count&& __r) noexcept
+      : _M_pi(__r._M_pi)
+      { __r._M_pi = nullptr; }
+
+      ~__weak_count() noexcept
+      {
+	if (_M_pi != nullptr)
+	  _M_pi->_M_weak_release();
+      }
+
+      __weak_count&
+      operator=(const __shared_count<_Lp>& __r) noexcept
+      {
+	_Sp_counted_base<_Lp>* __tmp = __r._M_pi;
+	if (__tmp != nullptr)
+	  __tmp->_M_weak_add_ref();
+	if (_M_pi != nullptr)
+	  _M_pi->_M_weak_release();
+	_M_pi = __tmp;
+	return *this;
+      }
+
+      __weak_count&
+      operator=(const __weak_count& __r) noexcept
+      {
+	_Sp_counted_base<_Lp>* __tmp = __r._M_pi;
+	if (__tmp != nullptr)
+	  __tmp->_M_weak_add_ref();
+	if (_M_pi != nullptr)
+	  _M_pi->_M_weak_release();
+	_M_pi = __tmp;
+	return *this;
+      }
+
+      __weak_count&
+      operator=(__weak_count&& __r) noexcept
+      {
+	if (_M_pi != nullptr)
+	  _M_pi->_M_weak_release();
+	_M_pi = __r._M_pi;
+        __r._M_pi = nullptr;
+	return *this;
+      }
+
+      void
+      _M_swap(__weak_count& __r) noexcept
+      {
+	_Sp_counted_base<_Lp>* __tmp = __r._M_pi;
+	__r._M_pi = _M_pi;
+	_M_pi = __tmp;
+      }
+
+      long
+      _M_get_use_count() const noexcept
+      { return _M_pi != nullptr ? _M_pi->_M_get_use_count() : 0; }
+
+      bool
+      _M_less(const __weak_count& __rhs) const noexcept
+      { return std::less<_Sp_counted_base<_Lp>*>()(this->_M_pi, __rhs._M_pi); }
+
+      bool
+      _M_less(const __shared_count<_Lp>& __rhs) const noexcept
+      { return std::less<_Sp_counted_base<_Lp>*>()(this->_M_pi, __rhs._M_pi); }
+
+      // Friend function injected into enclosing namespace and found by ADL
+      friend inline bool
+      operator==(const __weak_count& __a, const __weak_count& __b) noexcept
+      { return __a._M_pi == __b._M_pi; }
+
+    private:
+      friend class __shared_count<_Lp>;
+#if __cplusplus >= 202002L
+      template<typename> friend class _Sp_atomic;
+#endif
+
+      _Sp_counted_base<_Lp>*  _M_pi;
+    };
+
+  // Now that __weak_count is defined we can define this constructor:
+  template<_Lock_policy _Lp>
+    inline
+    __shared_count<_Lp>::__shared_count(const __weak_count<_Lp>& __r)
+    : _M_pi(__r._M_pi)
+    {
+      if (_M_pi == nullptr || !_M_pi->_M_add_ref_lock_nothrow())
+	__throw_bad_weak_ptr();
+    }
+
+  // Now that __weak_count is defined we can define this constructor:
+  template<_Lock_policy _Lp>
+    inline
+    __shared_count<_Lp>::
+    __shared_count(const __weak_count<_Lp>& __r, std::nothrow_t) noexcept
+    : _M_pi(__r._M_pi)
+    {
+      if (_M_pi && !_M_pi->_M_add_ref_lock_nothrow())
+	_M_pi = nullptr;
+    }
+
+  // Helper traits for shared_ptr of array:
+
+  // A pointer type Y* is said to be compatible with a pointer type T* when
+  // either Y* is convertible to T* or Y is U[N] and T is U cv [].
+  template<typename _Yp_ptr, typename _Tp_ptr>
+    struct __sp_compatible_with
+    : false_type
+    { };
+
+  template<typename _Yp, typename _Tp>
+    struct __sp_compatible_with<_Yp*, _Tp*>
+    : is_convertible<_Yp*, _Tp*>::type
+    { };
+
+  template<typename _Up, size_t _Nm>
+    struct __sp_compatible_with<_Up(*)[_Nm], _Up(*)[]>
+    : true_type
+    { };
+
+  template<typename _Up, size_t _Nm>
+    struct __sp_compatible_with<_Up(*)[_Nm], const _Up(*)[]>
+    : true_type
+    { };
+
+  template<typename _Up, size_t _Nm>
+    struct __sp_compatible_with<_Up(*)[_Nm], volatile _Up(*)[]>
+    : true_type
+    { };
+
+  template<typename _Up, size_t _Nm>
+    struct __sp_compatible_with<_Up(*)[_Nm], const volatile _Up(*)[]>
+    : true_type
+    { };
+
+  // Test conversion from Y(*)[N] to U(*)[N] without forming invalid type Y[N].
+  template<typename _Up, size_t _Nm, typename _Yp, typename = void>
+    struct __sp_is_constructible_arrN
+    : false_type
+    { };
+
+  template<typename _Up, size_t _Nm, typename _Yp>
+    struct __sp_is_constructible_arrN<_Up, _Nm, _Yp, __void_t<_Yp[_Nm]>>
+    : is_convertible<_Yp(*)[_Nm], _Up(*)[_Nm]>::type
+    { };
+
+  // Test conversion from Y(*)[] to U(*)[] without forming invalid type Y[].
+  template<typename _Up, typename _Yp, typename = void>
+    struct __sp_is_constructible_arr
+    : false_type
+    { };
+
+  template<typename _Up, typename _Yp>
+    struct __sp_is_constructible_arr<_Up, _Yp, __void_t<_Yp[]>>
+    : is_convertible<_Yp(*)[], _Up(*)[]>::type
+    { };
+
+  // Trait to check if shared_ptr<T> can be constructed from Y*.
+  template<typename _Tp, typename _Yp>
+    struct __sp_is_constructible;
+
+  // When T is U[N], Y(*)[N] shall be convertible to T*;
+  template<typename _Up, size_t _Nm, typename _Yp>
+    struct __sp_is_constructible<_Up[_Nm], _Yp>
+    : __sp_is_constructible_arrN<_Up, _Nm, _Yp>::type
+    { };
+
+  // when T is U[], Y(*)[] shall be convertible to T*;
+  template<typename _Up, typename _Yp>
+    struct __sp_is_constructible<_Up[], _Yp>
+    : __sp_is_constructible_arr<_Up, _Yp>::type
+    { };
+
+  // otherwise, Y* shall be convertible to T*.
+  template<typename _Tp, typename _Yp>
+    struct __sp_is_constructible
+    : is_convertible<_Yp*, _Tp*>::type
+    { };
+
+
+  // Define operator* and operator-> for shared_ptr<T>.
+  template<typename _Tp, _Lock_policy _Lp,
+	   bool = is_array<_Tp>::value, bool = is_void<_Tp>::value>
+    class __shared_ptr_access
+    {
+    public:
+      using element_type = _Tp;
+
+      element_type&
+      operator*() const noexcept
+      {
+	__glibcxx_assert(_M_get() != nullptr);
+	return *_M_get();
+      }
+
+      element_type*
+      operator->() const noexcept
+      {
+	_GLIBCXX_DEBUG_PEDASSERT(_M_get() != nullptr);
+	return _M_get();
+      }
+
+    private:
+      element_type*
+      _M_get() const noexcept
+      { return static_cast<const __shared_ptr<_Tp, _Lp>*>(this)->get(); }
+    };
+
+  // Define operator-> for shared_ptr<cv void>.
+  template<typename _Tp, _Lock_policy _Lp>
+    class __shared_ptr_access<_Tp, _Lp, false, true>
+    {
+    public:
+      using element_type = _Tp;
+
+      element_type*
+      operator->() const noexcept
+      {
+	auto __ptr = static_cast<const __shared_ptr<_Tp, _Lp>*>(this)->get();
+	_GLIBCXX_DEBUG_PEDASSERT(__ptr != nullptr);
+	return __ptr;
+      }
+    };
+
+  // Define operator[] for shared_ptr<T[]> and shared_ptr<T[N]>.
+  template<typename _Tp, _Lock_policy _Lp>
+    class __shared_ptr_access<_Tp, _Lp, true, false>
+    {
+    public:
+      using element_type = typename remove_extent<_Tp>::type;
+
+#if __cplusplus <= 201402L
+      [[__deprecated__("shared_ptr<T[]>::operator* is absent from C++17")]]
+      element_type&
+      operator*() const noexcept
+      {
+	__glibcxx_assert(_M_get() != nullptr);
+	return *_M_get();
+      }
+
+      [[__deprecated__("shared_ptr<T[]>::operator-> is absent from C++17")]]
+      element_type*
+      operator->() const noexcept
+      {
+	_GLIBCXX_DEBUG_PEDASSERT(_M_get() != nullptr);
+	return _M_get();
+      }
+#endif
+
+      element_type&
+      operator[](ptrdiff_t __i) const noexcept
+      {
+	__glibcxx_assert(_M_get() != nullptr);
+	__glibcxx_assert(!extent<_Tp>::value || __i < extent<_Tp>::value);
+	return _M_get()[__i];
+      }
+
+    private:
+      element_type*
+      _M_get() const noexcept
+      { return static_cast<const __shared_ptr<_Tp, _Lp>*>(this)->get(); }
+    };
+
+  template<typename _Tp, _Lock_policy _Lp>
+    class __shared_ptr
+    : public __shared_ptr_access<_Tp, _Lp>
+    {
+    public:
+      using element_type = typename remove_extent<_Tp>::type;
+
+    private:
+      // Constraint for taking ownership of a pointer of type _Yp*:
+      template<typename _Yp>
+	using _SafeConv
+	  = typename enable_if<__sp_is_constructible<_Tp, _Yp>::value>::type;
+
+      // Constraint for construction from shared_ptr and weak_ptr:
+      template<typename _Yp, typename _Res = void>
+	using _Compatible = typename
+	  enable_if<__sp_compatible_with<_Yp*, _Tp*>::value, _Res>::type;
+
+      // Constraint for assignment from shared_ptr and weak_ptr:
+      template<typename _Yp>
+	using _Assignable = _Compatible<_Yp, __shared_ptr&>;
+
+      // Constraint for construction from unique_ptr:
+      template<typename _Yp, typename _Del, typename _Res = void,
+	       typename _Ptr = typename unique_ptr<_Yp, _Del>::pointer>
+	using _UniqCompatible = __enable_if_t<__and_<
+	  __sp_compatible_with<_Yp*, _Tp*>,
+	  is_convertible<_Ptr, element_type*>,
+	  is_move_constructible<_Del>
+	  >::value, _Res>;
+
+      // Constraint for assignment from unique_ptr:
+      template<typename _Yp, typename _Del>
+	using _UniqAssignable = _UniqCompatible<_Yp, _Del, __shared_ptr&>;
+
+    public:
+
+#if __cplusplus > 201402L
+      using weak_type = __weak_ptr<_Tp, _Lp>;
+#endif
+
+      constexpr __shared_ptr() noexcept
+      : _M_ptr(0), _M_refcount()
+      { }
+
+      template<typename _Yp, typename = _SafeConv<_Yp>>
+	explicit
+	__shared_ptr(_Yp* __p)
+	: _M_ptr(__p), _M_refcount(__p, typename is_array<_Tp>::type())
+	{
+	  static_assert( !is_void<_Yp>::value, "incomplete type" );
+	  static_assert( sizeof(_Yp) > 0, "incomplete type" );
+	  _M_enable_shared_from_this_with(__p);
+	}
+
+      template<typename _Yp, typename _Deleter, typename = _SafeConv<_Yp>>
+	__shared_ptr(_Yp* __p, _Deleter __d)
+	: _M_ptr(__p), _M_refcount(__p, std::move(__d))
+	{
+	  static_assert(__is_invocable<_Deleter&, _Yp*&>::value,
+	      "deleter expression d(p) is well-formed");
+	  _M_enable_shared_from_this_with(__p);
+	}
+
+      template<typename _Yp, typename _Deleter, typename _Alloc,
+	       typename = _SafeConv<_Yp>>
+	__shared_ptr(_Yp* __p, _Deleter __d, _Alloc __a)
+	: _M_ptr(__p), _M_refcount(__p, std::move(__d), std::move(__a))
+	{
+	  static_assert(__is_invocable<_Deleter&, _Yp*&>::value,
+	      "deleter expression d(p) is well-formed");
+	  _M_enable_shared_from_this_with(__p);
+	}
+
+      template<typename _Deleter>
+	__shared_ptr(nullptr_t __p, _Deleter __d)
+	: _M_ptr(0), _M_refcount(__p, std::move(__d))
+	{ }
+
+      template<typename _Deleter, typename _Alloc>
+        __shared_ptr(nullptr_t __p, _Deleter __d, _Alloc __a)
+	: _M_ptr(0), _M_refcount(__p, std::move(__d), std::move(__a))
+	{ }
+
+      // Aliasing constructor
+      template<typename _Yp>
+	__shared_ptr(const __shared_ptr<_Yp, _Lp>& __r,
+		     element_type* __p) noexcept
+	: _M_ptr(__p), _M_refcount(__r._M_refcount) // never throws
+	{ }
+
+      // Aliasing constructor
+      template<typename _Yp>
+	__shared_ptr(__shared_ptr<_Yp, _Lp>&& __r,
+		     element_type* __p) noexcept
+	: _M_ptr(__p), _M_refcount()
+	{
+	  _M_refcount._M_swap(__r._M_refcount);
+	  __r._M_ptr = nullptr;
+	}
+
+      __shared_ptr(const __shared_ptr&) noexcept = default;
+      __shared_ptr& operator=(const __shared_ptr&) noexcept = default;
+      ~__shared_ptr() = default;
+
+      template<typename _Yp, typename = _Compatible<_Yp>>
+	__shared_ptr(const __shared_ptr<_Yp, _Lp>& __r) noexcept
+	: _M_ptr(__r._M_ptr), _M_refcount(__r._M_refcount)
+	{ }
+
+      __shared_ptr(__shared_ptr&& __r) noexcept
+      : _M_ptr(__r._M_ptr), _M_refcount()
+      {
+	_M_refcount._M_swap(__r._M_refcount);
+	__r._M_ptr = nullptr;
+      }
+
+      template<typename _Yp, typename = _Compatible<_Yp>>
+	__shared_ptr(__shared_ptr<_Yp, _Lp>&& __r) noexcept
+	: _M_ptr(__r._M_ptr), _M_refcount()
+	{
+	  _M_refcount._M_swap(__r._M_refcount);
+	  __r._M_ptr = nullptr;
+	}
+
+      template<typename _Yp, typename = _Compatible<_Yp>>
+	explicit __shared_ptr(const __weak_ptr<_Yp, _Lp>& __r)
+	: _M_refcount(__r._M_refcount) // may throw
+	{
+	  // It is now safe to copy __r._M_ptr, as
+	  // _M_refcount(__r._M_refcount) did not throw.
+	  _M_ptr = __r._M_ptr;
+	}
+
+      // If an exception is thrown this constructor has no effect.
+      template<typename _Yp, typename _Del,
+	       typename = _UniqCompatible<_Yp, _Del>>
+	__shared_ptr(unique_ptr<_Yp, _Del>&& __r)
+	: _M_ptr(__r.get()), _M_refcount()
+	{
+	  auto __raw = __to_address(__r.get());
+	  _M_refcount = __shared_count<_Lp>(std::move(__r));
+	  _M_enable_shared_from_this_with(__raw);
+	}
+
+#if __cplusplus <= 201402L && _GLIBCXX_USE_DEPRECATED
+    protected:
+      // If an exception is thrown this constructor has no effect.
+      template<typename _Tp1, typename _Del,
+	       typename enable_if<__and_<
+		 __not_<is_array<_Tp>>, is_array<_Tp1>,
+	         is_convertible<typename unique_ptr<_Tp1, _Del>::pointer, _Tp*>
+	       >::value, bool>::type = true>
+	__shared_ptr(unique_ptr<_Tp1, _Del>&& __r, __sp_array_delete)
+	: _M_ptr(__r.get()), _M_refcount()
+	{
+	  auto __raw = __to_address(__r.get());
+	  _M_refcount = __shared_count<_Lp>(std::move(__r));
+	  _M_enable_shared_from_this_with(__raw);
+	}
+    public:
+#endif
+
+#if _GLIBCXX_USE_DEPRECATED
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+      // Postcondition: use_count() == 1 and __r.get() == 0
+      template<typename _Yp, typename = _Compatible<_Yp>>
+	__shared_ptr(auto_ptr<_Yp>&& __r);
+#pragma GCC diagnostic pop
+#endif
+
+      constexpr __shared_ptr(nullptr_t) noexcept : __shared_ptr() { }
+
+      template<typename _Yp>
+	_Assignable<_Yp>
+	operator=(const __shared_ptr<_Yp, _Lp>& __r) noexcept
+	{
+	  _M_ptr = __r._M_ptr;
+	  _M_refcount = __r._M_refcount; // __shared_count::op= doesn't throw
+	  return *this;
+	}
+
+#if _GLIBCXX_USE_DEPRECATED
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+      template<typename _Yp>
+	_Assignable<_Yp>
+	operator=(auto_ptr<_Yp>&& __r)
+	{
+	  __shared_ptr(std::move(__r)).swap(*this);
+	  return *this;
+	}
+#pragma GCC diagnostic pop
+#endif
+
+      __shared_ptr&
+      operator=(__shared_ptr&& __r) noexcept
+      {
+	__shared_ptr(std::move(__r)).swap(*this);
+	return *this;
+      }
+
+      template<class _Yp>
+	_Assignable<_Yp>
+	operator=(__shared_ptr<_Yp, _Lp>&& __r) noexcept
+	{
+	  __shared_ptr(std::move(__r)).swap(*this);
+	  return *this;
+	}
+
+      template<typename _Yp, typename _Del>
+	_UniqAssignable<_Yp, _Del>
+	operator=(unique_ptr<_Yp, _Del>&& __r)
+	{
+	  __shared_ptr(std::move(__r)).swap(*this);
+	  return *this;
+	}
+
+      void
+      reset() noexcept
+      { __shared_ptr().swap(*this); }
+
+      template<typename _Yp>
+	_SafeConv<_Yp>
+	reset(_Yp* __p) // _Yp must be complete.
+	{
+	  // Catch self-reset errors.
+	  __glibcxx_assert(__p == nullptr || __p != _M_ptr);
+	  __shared_ptr(__p).swap(*this);
+	}
+
+      template<typename _Yp, typename _Deleter>
+	_SafeConv<_Yp>
+	reset(_Yp* __p, _Deleter __d)
+	{ __shared_ptr(__p, std::move(__d)).swap(*this); }
+
+      template<typename _Yp, typename _Deleter, typename _Alloc>
+	_SafeConv<_Yp>
+	reset(_Yp* __p, _Deleter __d, _Alloc __a)
+        { __shared_ptr(__p, std::move(__d), std::move(__a)).swap(*this); }
+
+      /// Return the stored pointer.
+      element_type*
+      get() const noexcept
+      { return _M_ptr; }
+
+      /// Return true if the stored pointer is not null.
+      explicit operator bool() const noexcept
+      { return _M_ptr != nullptr; }
+
+      /// Return true if use_count() == 1.
+      bool
+      unique() const noexcept
+      { return _M_refcount._M_unique(); }
+
+      /// If *this owns a pointer, return the number of owners, otherwise zero.
+      long
+      use_count() const noexcept
+      { return _M_refcount._M_get_use_count(); }
+
+      /// Exchange both the owned pointer and the stored pointer.
+      void
+      swap(__shared_ptr<_Tp, _Lp>& __other) noexcept
+      {
+	std::swap(_M_ptr, __other._M_ptr);
+	_M_refcount._M_swap(__other._M_refcount);
+      }
+
+      /** @brief Define an ordering based on ownership.
+       *
+       * This function defines a strict weak ordering between two shared_ptr
+       * or weak_ptr objects, such that one object is less than the other
+       * unless they share ownership of the same pointer, or are both empty.
+       * @{
+      */
+      template<typename _Tp1>
+	bool
+	owner_before(__shared_ptr<_Tp1, _Lp> const& __rhs) const noexcept
+	{ return _M_refcount._M_less(__rhs._M_refcount); }
+
+      template<typename _Tp1>
+	bool
+	owner_before(__weak_ptr<_Tp1, _Lp> const& __rhs) const noexcept
+	{ return _M_refcount._M_less(__rhs._M_refcount); }
+      /// @}
+
+    protected:
+      // This constructor is non-standard, it is used by allocate_shared.
+      template<typename _Alloc, typename... _Args>
+	__shared_ptr(_Sp_alloc_shared_tag<_Alloc> __tag, _Args&&... __args)
+	: _M_ptr(), _M_refcount(_M_ptr, __tag, std::forward<_Args>(__args)...)
+	{ _M_enable_shared_from_this_with(_M_ptr); }
+
+      template<typename _Tp1, _Lock_policy _Lp1, typename _Alloc,
+	       typename... _Args>
+	friend __shared_ptr<_Tp1, _Lp1>
+	__allocate_shared(const _Alloc& __a, _Args&&... __args);
+
+#if __cpp_lib_shared_ptr_arrays >= 201707L
+      // This constructor is non-standard, it is used by allocate_shared<T[]>.
+      template<typename _Alloc, typename _Init = const remove_extent_t<_Tp>*>
+	__shared_ptr(const _Sp_counted_array_base<_Alloc>& __a,
+		     _Init __init = nullptr)
+	: _M_ptr(), _M_refcount(_M_ptr, __a, __init)
+	{ }
+#endif
+
+      // This constructor is used by __weak_ptr::lock() and
+      // shared_ptr::shared_ptr(const weak_ptr&, std::nothrow_t).
+      __shared_ptr(const __weak_ptr<_Tp, _Lp>& __r, std::nothrow_t) noexcept
+      : _M_refcount(__r._M_refcount, std::nothrow)
+      {
+	_M_ptr = _M_refcount._M_get_use_count() ? __r._M_ptr : nullptr;
+      }
+
+      friend class __weak_ptr<_Tp, _Lp>;
+
+    private:
+
+      template<typename _Yp>
+	using __esft_base_t = decltype(__enable_shared_from_this_base(
+	      std::declval<const __shared_count<_Lp>&>(),
+	      std::declval<_Yp*>()));
+
+      // Detect an accessible and unambiguous enable_shared_from_this base.
+      template<typename _Yp, typename = void>
+	struct __has_esft_base
+	: false_type { };
+
+      template<typename _Yp>
+	struct __has_esft_base<_Yp, __void_t<__esft_base_t<_Yp>>>
+	: __not_<is_array<_Tp>> { }; // No enable shared_from_this for arrays
+
+      template<typename _Yp, typename _Yp2 = typename remove_cv<_Yp>::type>
+	typename enable_if<__has_esft_base<_Yp2>::value>::type
+	_M_enable_shared_from_this_with(_Yp* __p) noexcept
+	{
+	  if (auto __base = __enable_shared_from_this_base(_M_refcount, __p))
+	    __base->_M_weak_assign(const_cast<_Yp2*>(__p), _M_refcount);
+	}
+
+      template<typename _Yp, typename _Yp2 = typename remove_cv<_Yp>::type>
+	typename enable_if<!__has_esft_base<_Yp2>::value>::type
+	_M_enable_shared_from_this_with(_Yp*) noexcept
+	{ }
+
+      void*
+      _M_get_deleter(const std::type_info& __ti) const noexcept
+      { return _M_refcount._M_get_deleter(__ti); }
+
+      template<typename _Tp1, _Lock_policy _Lp1> friend class __shared_ptr;
+      template<typename _Tp1, _Lock_policy _Lp1> friend class __weak_ptr;
+
+      template<typename _Del, typename _Tp1, _Lock_policy _Lp1>
+	friend _Del* get_deleter(const __shared_ptr<_Tp1, _Lp1>&) noexcept;
+
+      template<typename _Del, typename _Tp1>
+	friend _Del* get_deleter(const shared_ptr<_Tp1>&) noexcept;
+
+#if __cplusplus >= 202002L
+      friend _Sp_atomic<shared_ptr<_Tp>>;
+#endif
+
+      element_type*	   _M_ptr;         // Contained pointer.
+      __shared_count<_Lp>  _M_refcount;    // Reference counter.
+    };
+
+
+  // 20.7.2.2.7 shared_ptr comparisons
+  template<typename _Tp1, typename _Tp2, _Lock_policy _Lp>
+    inline bool
+    operator==(const __shared_ptr<_Tp1, _Lp>& __a,
+	       const __shared_ptr<_Tp2, _Lp>& __b) noexcept
+    { return __a.get() == __b.get(); }
+
+  template<typename _Tp, _Lock_policy _Lp>
+    inline bool
+    operator==(const __shared_ptr<_Tp, _Lp>& __a, nullptr_t) noexcept
+    { return !__a; }
+
+#ifdef __cpp_lib_three_way_comparison
+  template<typename _Tp, typename _Up, _Lock_policy _Lp>
+    inline strong_ordering
+    operator<=>(const __shared_ptr<_Tp, _Lp>& __a,
+		const __shared_ptr<_Up, _Lp>& __b) noexcept
+    { return compare_three_way()(__a.get(), __b.get()); }
+
+  template<typename _Tp, _Lock_policy _Lp>
+    inline strong_ordering
+    operator<=>(const __shared_ptr<_Tp, _Lp>& __a, nullptr_t) noexcept
+    {
+      using pointer = typename __shared_ptr<_Tp, _Lp>::element_type*;
+      return compare_three_way()(__a.get(), static_cast<pointer>(nullptr));
+    }
+#else
+  template<typename _Tp, _Lock_policy _Lp>
+    inline bool
+    operator==(nullptr_t, const __shared_ptr<_Tp, _Lp>& __a) noexcept
+    { return !__a; }
+
+  template<typename _Tp1, typename _Tp2, _Lock_policy _Lp>
+    inline bool
+    operator!=(const __shared_ptr<_Tp1, _Lp>& __a,
+	       const __shared_ptr<_Tp2, _Lp>& __b) noexcept
+    { return __a.get() != __b.get(); }
+
+  template<typename _Tp, _Lock_policy _Lp>
+    inline bool
+    operator!=(const __shared_ptr<_Tp, _Lp>& __a, nullptr_t) noexcept
+    { return (bool)__a; }
+
+  template<typename _Tp, _Lock_policy _Lp>
+    inline bool
+    operator!=(nullptr_t, const __shared_ptr<_Tp, _Lp>& __a) noexcept
+    { return (bool)__a; }
+
+  template<typename _Tp, typename _Up, _Lock_policy _Lp>
+    inline bool
+    operator<(const __shared_ptr<_Tp, _Lp>& __a,
+	      const __shared_ptr<_Up, _Lp>& __b) noexcept
+    {
+      using _Tp_elt = typename __shared_ptr<_Tp, _Lp>::element_type;
+      using _Up_elt = typename __shared_ptr<_Up, _Lp>::element_type;
+      using _Vp = typename common_type<_Tp_elt*, _Up_elt*>::type;
+      return less<_Vp>()(__a.get(), __b.get());
+    }
+
+  template<typename _Tp, _Lock_policy _Lp>
+    inline bool
+    operator<(const __shared_ptr<_Tp, _Lp>& __a, nullptr_t) noexcept
+    {
+      using _Tp_elt = typename __shared_ptr<_Tp, _Lp>::element_type;
+      return less<_Tp_elt*>()(__a.get(), nullptr);
+    }
+
+  template<typename _Tp, _Lock_policy _Lp>
+    inline bool
+    operator<(nullptr_t, const __shared_ptr<_Tp, _Lp>& __a) noexcept
+    {
+      using _Tp_elt = typename __shared_ptr<_Tp, _Lp>::element_type;
+      return less<_Tp_elt*>()(nullptr, __a.get());
+    }
+
+  template<typename _Tp1, typename _Tp2, _Lock_policy _Lp>
+    inline bool
+    operator<=(const __shared_ptr<_Tp1, _Lp>& __a,
+	       const __shared_ptr<_Tp2, _Lp>& __b) noexcept
+    { return !(__b < __a); }
+
+  template<typename _Tp, _Lock_policy _Lp>
+    inline bool
+    operator<=(const __shared_ptr<_Tp, _Lp>& __a, nullptr_t) noexcept
+    { return !(nullptr < __a); }
+
+  template<typename _Tp, _Lock_policy _Lp>
+    inline bool
+    operator<=(nullptr_t, const __shared_ptr<_Tp, _Lp>& __a) noexcept
+    { return !(__a < nullptr); }
+
+  template<typename _Tp1, typename _Tp2, _Lock_policy _Lp>
+    inline bool
+    operator>(const __shared_ptr<_Tp1, _Lp>& __a,
+	      const __shared_ptr<_Tp2, _Lp>& __b) noexcept
+    { return (__b < __a); }
+
+  template<typename _Tp, _Lock_policy _Lp>
+    inline bool
+    operator>(const __shared_ptr<_Tp, _Lp>& __a, nullptr_t) noexcept
+    { return nullptr < __a; }
+
+  template<typename _Tp, _Lock_policy _Lp>
+    inline bool
+    operator>(nullptr_t, const __shared_ptr<_Tp, _Lp>& __a) noexcept
+    { return __a < nullptr; }
+
+  template<typename _Tp1, typename _Tp2, _Lock_policy _Lp>
+    inline bool
+    operator>=(const __shared_ptr<_Tp1, _Lp>& __a,
+	       const __shared_ptr<_Tp2, _Lp>& __b) noexcept
+    { return !(__a < __b); }
+
+  template<typename _Tp, _Lock_policy _Lp>
+    inline bool
+    operator>=(const __shared_ptr<_Tp, _Lp>& __a, nullptr_t) noexcept
+    { return !(__a < nullptr); }
+
+  template<typename _Tp, _Lock_policy _Lp>
+    inline bool
+    operator>=(nullptr_t, const __shared_ptr<_Tp, _Lp>& __a) noexcept
+    { return !(nullptr < __a); }
+#endif // three-way comparison
+
+  // 20.7.2.2.8 shared_ptr specialized algorithms.
+  template<typename _Tp, _Lock_policy _Lp>
+    inline void
+    swap(__shared_ptr<_Tp, _Lp>& __a, __shared_ptr<_Tp, _Lp>& __b) noexcept
+    { __a.swap(__b); }
+
+  // 20.7.2.2.9 shared_ptr casts
+
+  // The seemingly equivalent code:
+  // shared_ptr<_Tp, _Lp>(static_cast<_Tp*>(__r.get()))
+  // will eventually result in undefined behaviour, attempting to
+  // delete the same object twice.
+  /// static_pointer_cast
+  template<typename _Tp, typename _Tp1, _Lock_policy _Lp>
+    inline __shared_ptr<_Tp, _Lp>
+    static_pointer_cast(const __shared_ptr<_Tp1, _Lp>& __r) noexcept
+    {
+      using _Sp = __shared_ptr<_Tp, _Lp>;
+      return _Sp(__r, static_cast<typename _Sp::element_type*>(__r.get()));
+    }
+
+  // The seemingly equivalent code:
+  // shared_ptr<_Tp, _Lp>(const_cast<_Tp*>(__r.get()))
+  // will eventually result in undefined behaviour, attempting to
+  // delete the same object twice.
+  /// const_pointer_cast
+  template<typename _Tp, typename _Tp1, _Lock_policy _Lp>
+    inline __shared_ptr<_Tp, _Lp>
+    const_pointer_cast(const __shared_ptr<_Tp1, _Lp>& __r) noexcept
+    {
+      using _Sp = __shared_ptr<_Tp, _Lp>;
+      return _Sp(__r, const_cast<typename _Sp::element_type*>(__r.get()));
+    }
+
+  // The seemingly equivalent code:
+  // shared_ptr<_Tp, _Lp>(dynamic_cast<_Tp*>(__r.get()))
+  // will eventually result in undefined behaviour, attempting to
+  // delete the same object twice.
+  /// dynamic_pointer_cast
+  template<typename _Tp, typename _Tp1, _Lock_policy _Lp>
+    inline __shared_ptr<_Tp, _Lp>
+    dynamic_pointer_cast(const __shared_ptr<_Tp1, _Lp>& __r) noexcept
+    {
+      using _Sp = __shared_ptr<_Tp, _Lp>;
+      if (auto* __p = dynamic_cast<typename _Sp::element_type*>(__r.get()))
+	return _Sp(__r, __p);
+      return _Sp();
+    }
+
+#if __cplusplus > 201402L
+  template<typename _Tp, typename _Tp1, _Lock_policy _Lp>
+    inline __shared_ptr<_Tp, _Lp>
+    reinterpret_pointer_cast(const __shared_ptr<_Tp1, _Lp>& __r) noexcept
+    {
+      using _Sp = __shared_ptr<_Tp, _Lp>;
+      return _Sp(__r, reinterpret_cast<typename _Sp::element_type*>(__r.get()));
+    }
+#endif
+
+  template<typename _Tp, _Lock_policy _Lp>
+    class __weak_ptr
+    {
+      template<typename _Yp, typename _Res = void>
+	using _Compatible = typename
+	  enable_if<__sp_compatible_with<_Yp*, _Tp*>::value, _Res>::type;
+
+      // Constraint for assignment from shared_ptr and weak_ptr:
+      template<typename _Yp>
+	using _Assignable = _Compatible<_Yp, __weak_ptr&>;
+
+    public:
+      using element_type = typename remove_extent<_Tp>::type;
+
+      constexpr __weak_ptr() noexcept
+      : _M_ptr(nullptr), _M_refcount()
+      { }
+
+      __weak_ptr(const __weak_ptr&) noexcept = default;
+
+      ~__weak_ptr() = default;
+
+      // The "obvious" converting constructor implementation:
+      //
+      //  template<typename _Tp1>
+      //    __weak_ptr(const __weak_ptr<_Tp1, _Lp>& __r)
+      //    : _M_ptr(__r._M_ptr), _M_refcount(__r._M_refcount) // never throws
+      //    { }
+      //
+      // has a serious problem.
+      //
+      //  __r._M_ptr may already have been invalidated. The _M_ptr(__r._M_ptr)
+      //  conversion may require access to *__r._M_ptr (virtual inheritance).
+      //
+      // It is not possible to avoid spurious access violations since
+      // in multithreaded programs __r._M_ptr may be invalidated at any point.
+      template<typename _Yp, typename = _Compatible<_Yp>>
+	__weak_ptr(const __weak_ptr<_Yp, _Lp>& __r) noexcept
+	: _M_refcount(__r._M_refcount)
+        { _M_ptr = __r.lock().get(); }
+
+      template<typename _Yp, typename = _Compatible<_Yp>>
+	__weak_ptr(const __shared_ptr<_Yp, _Lp>& __r) noexcept
+	: _M_ptr(__r._M_ptr), _M_refcount(__r._M_refcount)
+	{ }
+
+      __weak_ptr(__weak_ptr&& __r) noexcept
+      : _M_ptr(__r._M_ptr), _M_refcount(std::move(__r._M_refcount))
+      { __r._M_ptr = nullptr; }
+
+      template<typename _Yp, typename = _Compatible<_Yp>>
+	__weak_ptr(__weak_ptr<_Yp, _Lp>&& __r) noexcept
+	: _M_ptr(__r.lock().get()), _M_refcount(std::move(__r._M_refcount))
+        { __r._M_ptr = nullptr; }
+
+      __weak_ptr&
+      operator=(const __weak_ptr& __r) noexcept = default;
+
+      template<typename _Yp>
+	_Assignable<_Yp>
+	operator=(const __weak_ptr<_Yp, _Lp>& __r) noexcept
+	{
+	  _M_ptr = __r.lock().get();
+	  _M_refcount = __r._M_refcount;
+	  return *this;
+	}
+
+      template<typename _Yp>
+	_Assignable<_Yp>
+	operator=(const __shared_ptr<_Yp, _Lp>& __r) noexcept
+	{
+	  _M_ptr = __r._M_ptr;
+	  _M_refcount = __r._M_refcount;
+	  return *this;
+	}
+
+      __weak_ptr&
+      operator=(__weak_ptr&& __r) noexcept
+      {
+	_M_ptr = __r._M_ptr;
+	_M_refcount = std::move(__r._M_refcount);
+	__r._M_ptr = nullptr;
+	return *this;
+      }
+
+      template<typename _Yp>
+	_Assignable<_Yp>
+	operator=(__weak_ptr<_Yp, _Lp>&& __r) noexcept
+	{
+	  _M_ptr = __r.lock().get();
+	  _M_refcount = std::move(__r._M_refcount);
+	  __r._M_ptr = nullptr;
+	  return *this;
+	}
+
+      __shared_ptr<_Tp, _Lp>
+      lock() const noexcept
+      { return __shared_ptr<element_type, _Lp>(*this, std::nothrow); }
+
+      long
+      use_count() const noexcept
+      { return _M_refcount._M_get_use_count(); }
+
+      bool
+      expired() const noexcept
+      { return _M_refcount._M_get_use_count() == 0; }
+
+      template<typename _Tp1>
+	bool
+	owner_before(const __shared_ptr<_Tp1, _Lp>& __rhs) const noexcept
+	{ return _M_refcount._M_less(__rhs._M_refcount); }
+
+      template<typename _Tp1>
+	bool
+	owner_before(const __weak_ptr<_Tp1, _Lp>& __rhs) const noexcept
+	{ return _M_refcount._M_less(__rhs._M_refcount); }
+
+      void
+      reset() noexcept
+      { __weak_ptr().swap(*this); }
+
+      void
+      swap(__weak_ptr& __s) noexcept
+      {
+	std::swap(_M_ptr, __s._M_ptr);
+	_M_refcount._M_swap(__s._M_refcount);
+      }
+
+    private:
+      // Used by __enable_shared_from_this.
+      void
+      _M_assign(_Tp* __ptr, const __shared_count<_Lp>& __refcount) noexcept
+      {
+	if (use_count() == 0)
+	  {
+	    _M_ptr = __ptr;
+	    _M_refcount = __refcount;
+	  }
+      }
+
+      template<typename _Tp1, _Lock_policy _Lp1> friend class __shared_ptr;
+      template<typename _Tp1, _Lock_policy _Lp1> friend class __weak_ptr;
+      friend class __enable_shared_from_this<_Tp, _Lp>;
+      friend class enable_shared_from_this<_Tp>;
+#if __cplusplus >= 202002L
+      friend _Sp_atomic<weak_ptr<_Tp>>;
+#endif
+
+      element_type*	 _M_ptr;         // Contained pointer.
+      __weak_count<_Lp>  _M_refcount;    // Reference counter.
+    };
+
+  // 20.7.2.3.6 weak_ptr specialized algorithms.
+  template<typename _Tp, _Lock_policy _Lp>
+    inline void
+    swap(__weak_ptr<_Tp, _Lp>& __a, __weak_ptr<_Tp, _Lp>& __b) noexcept
+    { __a.swap(__b); }
+
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+  template<typename _Tp, typename _Tp1>
+    struct _Sp_owner_less : public binary_function<_Tp, _Tp, bool>
+    {
+      bool
+      operator()(const _Tp& __lhs, const _Tp& __rhs) const noexcept
+      { return __lhs.owner_before(__rhs); }
+
+      bool
+      operator()(const _Tp& __lhs, const _Tp1& __rhs) const noexcept
+      { return __lhs.owner_before(__rhs); }
+
+      bool
+      operator()(const _Tp1& __lhs, const _Tp& __rhs) const noexcept
+      { return __lhs.owner_before(__rhs); }
+    };
+#pragma GCC diagnostic pop
+
+  template<>
+    struct _Sp_owner_less<void, void>
+    {
+      template<typename _Tp, typename _Up>
+	auto
+	operator()(const _Tp& __lhs, const _Up& __rhs) const noexcept
+	-> decltype(__lhs.owner_before(__rhs))
+	{ return __lhs.owner_before(__rhs); }
+
+      using is_transparent = void;
+    };
+
+  template<typename _Tp, _Lock_policy _Lp>
+    struct owner_less<__shared_ptr<_Tp, _Lp>>
+    : public _Sp_owner_less<__shared_ptr<_Tp, _Lp>, __weak_ptr<_Tp, _Lp>>
+    { };
+
+  template<typename _Tp, _Lock_policy _Lp>
+    struct owner_less<__weak_ptr<_Tp, _Lp>>
+    : public _Sp_owner_less<__weak_ptr<_Tp, _Lp>, __shared_ptr<_Tp, _Lp>>
+    { };
+
+
+  template<typename _Tp, _Lock_policy _Lp>
+    class __enable_shared_from_this
+    {
+    protected:
+      constexpr __enable_shared_from_this() noexcept { }
+
+      __enable_shared_from_this(const __enable_shared_from_this&) noexcept { }
+
+      __enable_shared_from_this&
+      operator=(const __enable_shared_from_this&) noexcept
+      { return *this; }
+
+      ~__enable_shared_from_this() { }
+
+    public:
+      __shared_ptr<_Tp, _Lp>
+      shared_from_this()
+      { return __shared_ptr<_Tp, _Lp>(this->_M_weak_this); }
+
+      __shared_ptr<const _Tp, _Lp>
+      shared_from_this() const
+      { return __shared_ptr<const _Tp, _Lp>(this->_M_weak_this); }
+
+#if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11
+      __weak_ptr<_Tp, _Lp>
+      weak_from_this() noexcept
+      { return this->_M_weak_this; }
+
+      __weak_ptr<const _Tp, _Lp>
+      weak_from_this() const noexcept
+      { return this->_M_weak_this; }
+#endif
+
+    private:
+      template<typename _Tp1>
+	void
+	_M_weak_assign(_Tp1* __p, const __shared_count<_Lp>& __n) const noexcept
+	{ _M_weak_this._M_assign(__p, __n); }
+
+      friend const __enable_shared_from_this*
+      __enable_shared_from_this_base(const __shared_count<_Lp>&,
+				     const __enable_shared_from_this* __p)
+      { return __p; }
+
+      template<typename, _Lock_policy>
+	friend class __shared_ptr;
+
+      mutable __weak_ptr<_Tp, _Lp>  _M_weak_this;
+    };
+
+  template<typename _Tp, _Lock_policy _Lp = __default_lock_policy,
+	   typename _Alloc, typename... _Args>
+    inline __shared_ptr<_Tp, _Lp>
+    __allocate_shared(const _Alloc& __a, _Args&&... __args)
+    {
+      static_assert(!is_array<_Tp>::value, "make_shared<T[]> not supported");
+
+      return __shared_ptr<_Tp, _Lp>(_Sp_alloc_shared_tag<_Alloc>{__a},
+				    std::forward<_Args>(__args)...);
+    }
+
+  template<typename _Tp, _Lock_policy _Lp = __default_lock_policy,
+	   typename... _Args>
+    inline __shared_ptr<_Tp, _Lp>
+    __make_shared(_Args&&... __args)
+    {
+      typedef typename std::remove_const<_Tp>::type _Tp_nc;
+      return std::__allocate_shared<_Tp, _Lp>(std::allocator<_Tp_nc>(),
+					      std::forward<_Args>(__args)...);
+    }
+
+  /// std::hash specialization for __shared_ptr.
+  template<typename _Tp, _Lock_policy _Lp>
+    struct hash<__shared_ptr<_Tp, _Lp>>
+    : public __hash_base<size_t, __shared_ptr<_Tp, _Lp>>
+    {
+      size_t
+      operator()(const __shared_ptr<_Tp, _Lp>& __s) const noexcept
+      {
+	return hash<typename __shared_ptr<_Tp, _Lp>::element_type*>()(
+	    __s.get());
+      }
+    };
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif // _SHARED_PTR_BASE_H
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@slice_array.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@slice_array.h
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@slice_array.h
@@ -0,0 +1,284 @@
+// The template and inlines for the -*- C++ -*- slice_array class.
+
+// Copyright (C) 1997-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/slice_array.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{valarray}
+ */
+
+// Written by Gabriel Dos Reis <Gabriel.Dos-Reis@DPTMaths.ENS-Cachan.Fr>
+
+#ifndef _SLICE_ARRAY_H
+#define _SLICE_ARRAY_H 1
+
+#pragma GCC system_header
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /**
+   * @addtogroup numeric_arrays
+   * @{
+   */
+
+  /**
+   *  @brief  Class defining one-dimensional subset of an array.
+   *
+   *  The slice class represents a one-dimensional subset of an array,
+   *  specified by three parameters: start offset, size, and stride.  The
+   *  start offset is the index of the first element of the array that is part
+   *  of the subset.  The size is the total number of elements in the subset.
+   *  Stride is the distance between each successive array element to include
+   *  in the subset.
+   *
+   *  For example, with an array of size 10, and a slice with offset 1, size 3
+   *  and stride 2, the subset consists of array elements 1, 3, and 5.
+   */
+  class slice
+  {
+  public:
+    ///  Construct an empty slice.
+    slice();
+
+    /**
+     *  @brief  Construct a slice.
+     *
+     *  @param  __o  Offset in array of first element.
+     *  @param  __d  Number of elements in slice.
+     *  @param  __s  Stride between array elements.
+     */
+    slice(size_t __o, size_t __d, size_t __s);
+
+    ///  Return array offset of first slice element.
+    size_t start() const;
+    ///  Return size of slice.
+    size_t size() const;
+    ///  Return array stride of slice.
+    size_t stride() const;
+
+#if __cpp_impl_three_way_comparison >= 201907L
+    /// Equality comparison
+    friend bool operator==(const slice&, const slice&) = default;
+#endif
+
+  private:
+    size_t _M_off;                      // offset
+    size_t _M_sz;			// size
+    size_t _M_st;			// stride unit
+  };
+
+  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+  // 543. valarray slice default constructor
+  inline
+  slice::slice() 
+  : _M_off(0), _M_sz(0), _M_st(0) {}
+
+  inline
+  slice::slice(size_t __o, size_t __d, size_t __s)
+  : _M_off(__o), _M_sz(__d), _M_st(__s) {}
+
+  inline size_t
+  slice::start() const
+  { return _M_off; }
+
+  inline size_t
+  slice::size() const
+  { return _M_sz; }
+
+  inline size_t
+  slice::stride() const
+  { return _M_st; }
+
+  /**
+   *  @brief  Reference to one-dimensional subset of an array.
+   *
+   *  A slice_array is a reference to the actual elements of an array
+   *  specified by a slice.  The way to get a slice_array is to call
+   *  operator[](slice) on a valarray.  The returned slice_array then permits
+   *  carrying operations out on the referenced subset of elements in the
+   *  original valarray.  For example, operator+=(valarray) will add values
+   *  to the subset of elements in the underlying valarray this slice_array
+   *  refers to.
+   *
+   *  @param  Tp  Element type.
+   */
+  template<typename _Tp>
+    class slice_array
+    {
+    public:
+      typedef _Tp value_type;
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 253. valarray helper functions are almost entirely useless
+
+      ///  Copy constructor.  Both slices refer to the same underlying array.
+      slice_array(const slice_array&);
+
+      ///  Assignment operator.  Assigns slice elements to corresponding
+      ///  elements of @a a.
+      slice_array& operator=(const slice_array&);
+
+      ///  Assign slice elements to corresponding elements of @a v.
+      void operator=(const valarray<_Tp>&) const;
+      ///  Multiply slice elements by corresponding elements of @a v.
+      void operator*=(const valarray<_Tp>&) const;
+      ///  Divide slice elements by corresponding elements of @a v.
+      void operator/=(const valarray<_Tp>&) const;
+      ///  Modulo slice elements by corresponding elements of @a v.
+      void operator%=(const valarray<_Tp>&) const;
+      ///  Add corresponding elements of @a v to slice elements.
+      void operator+=(const valarray<_Tp>&) const;
+      ///  Subtract corresponding elements of @a v from slice elements.
+      void operator-=(const valarray<_Tp>&) const;
+      ///  Logical xor slice elements with corresponding elements of @a v.
+      void operator^=(const valarray<_Tp>&) const;
+      ///  Logical and slice elements with corresponding elements of @a v.
+      void operator&=(const valarray<_Tp>&) const;
+      ///  Logical or slice elements with corresponding elements of @a v.
+      void operator|=(const valarray<_Tp>&) const;
+      ///  Left shift slice elements by corresponding elements of @a v.
+      void operator<<=(const valarray<_Tp>&) const;
+      ///  Right shift slice elements by corresponding elements of @a v.
+      void operator>>=(const valarray<_Tp>&) const;
+      ///  Assign all slice elements to @a t.
+      void operator=(const _Tp &) const;
+      //        ~slice_array ();
+
+      template<class _Dom>
+        void operator=(const _Expr<_Dom, _Tp>&) const;
+      template<class _Dom>
+	void operator*=(const _Expr<_Dom, _Tp>&) const;
+      template<class _Dom>
+	void operator/=(const _Expr<_Dom, _Tp>&) const;
+      template<class _Dom>
+	void operator%=(const _Expr<_Dom, _Tp>&) const;
+      template<class _Dom>
+	void operator+=(const _Expr<_Dom, _Tp>&) const;
+      template<class _Dom>
+	void operator-=(const _Expr<_Dom, _Tp>&) const;
+      template<class _Dom>
+	void operator^=(const _Expr<_Dom, _Tp>&) const;
+      template<class _Dom>
+	void operator&=(const _Expr<_Dom, _Tp>&) const;
+      template<class _Dom>
+	void operator|=(const _Expr<_Dom, _Tp>&) const;
+      template<class _Dom>
+	void operator<<=(const _Expr<_Dom, _Tp>&) const;
+      template<class _Dom>
+	void operator>>=(const _Expr<_Dom, _Tp>&) const;
+
+    private:
+      friend class valarray<_Tp>;
+      slice_array(_Array<_Tp>, const slice&);
+
+      const size_t      _M_sz;
+      const size_t      _M_stride;
+      const _Array<_Tp> _M_array;
+
+#if __cplusplus < 201103L
+      // not implemented
+      slice_array();
+#else
+    public:
+      slice_array() = delete;
+#endif
+    };
+
+  template<typename _Tp>
+    inline
+    slice_array<_Tp>::slice_array(_Array<_Tp> __a, const slice& __s)
+    : _M_sz(__s.size()), _M_stride(__s.stride()),
+      _M_array(__a.begin() + __s.start()) {}
+
+  template<typename _Tp>
+    inline
+    slice_array<_Tp>::slice_array(const slice_array<_Tp>& __a)
+    : _M_sz(__a._M_sz), _M_stride(__a._M_stride), _M_array(__a._M_array) {}
+
+  //    template<typename _Tp>
+  //    inline slice_array<_Tp>::~slice_array () {}
+
+  template<typename _Tp>
+    inline slice_array<_Tp>&
+    slice_array<_Tp>::operator=(const slice_array<_Tp>& __a)
+    {
+      std::__valarray_copy(__a._M_array, __a._M_sz, __a._M_stride,
+			   _M_array, _M_stride);
+      return *this;
+    }
+
+  template<typename _Tp>
+    inline void
+    slice_array<_Tp>::operator=(const _Tp& __t) const
+    { std::__valarray_fill(_M_array, _M_sz, _M_stride, __t); }
+
+  template<typename _Tp>
+    inline void
+    slice_array<_Tp>::operator=(const valarray<_Tp>& __v) const
+    { std::__valarray_copy(_Array<_Tp>(__v), _M_array, _M_sz, _M_stride); }
+
+  template<typename _Tp>
+  template<class _Dom>
+    inline void
+    slice_array<_Tp>::operator=(const _Expr<_Dom,_Tp>& __e) const
+    { std::__valarray_copy(__e, _M_sz, _M_array, _M_stride); }
+
+#undef _DEFINE_VALARRAY_OPERATOR
+#define _DEFINE_VALARRAY_OPERATOR(_Op,_Name)				\
+  template<typename _Tp>						\
+    inline void								\
+    slice_array<_Tp>::operator _Op##=(const valarray<_Tp>& __v) const	\
+    {									\
+      _Array_augmented_##_Name(_M_array, _M_sz, _M_stride, _Array<_Tp>(__v));\
+    }									\
+									\
+  template<typename _Tp>                                                \
+    template<class _Dom>				                \
+      inline void							\
+      slice_array<_Tp>::operator _Op##=(const _Expr<_Dom,_Tp>& __e) const\
+      {									\
+	  _Array_augmented_##_Name(_M_array, _M_stride, __e, _M_sz);	\
+      }
+
+
+_DEFINE_VALARRAY_OPERATOR(*, __multiplies)
+_DEFINE_VALARRAY_OPERATOR(/, __divides)
+_DEFINE_VALARRAY_OPERATOR(%, __modulus)
+_DEFINE_VALARRAY_OPERATOR(+, __plus)
+_DEFINE_VALARRAY_OPERATOR(-, __minus)
+_DEFINE_VALARRAY_OPERATOR(^, __bitwise_xor)
+_DEFINE_VALARRAY_OPERATOR(&, __bitwise_and)
+_DEFINE_VALARRAY_OPERATOR(|, __bitwise_or)
+_DEFINE_VALARRAY_OPERATOR(<<, __shift_left)
+_DEFINE_VALARRAY_OPERATOR(>>, __shift_right)
+
+#undef _DEFINE_VALARRAY_OPERATOR
+
+  /// @} group numeric_arrays
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif /* _SLICE_ARRAY_H */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@slice_array.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@slice_array.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@sstream.tcc b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@sstream.tcc
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@@ -0,0 +1,307 @@
+// String based streams -*- C++ -*-
+
+// Copyright (C) 1997-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/sstream.tcc
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{sstream}
+ */
+
+//
+// ISO C++ 14882: 27.7  String-based streams
+//
+
+#ifndef _SSTREAM_TCC
+#define _SSTREAM_TCC 1
+
+#pragma GCC system_header
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  template <class _CharT, class _Traits, class _Alloc>
+    typename basic_stringbuf<_CharT, _Traits, _Alloc>::int_type
+    basic_stringbuf<_CharT, _Traits, _Alloc>::
+    pbackfail(int_type __c)
+    {
+      int_type __ret = traits_type::eof();
+      if (this->eback() < this->gptr())
+	{
+	  // Try to put back __c into input sequence in one of three ways.
+	  // Order these tests done in is unspecified by the standard.
+	  const bool __testeof = traits_type::eq_int_type(__c, __ret);
+	  if (!__testeof)
+	    {
+	      const bool __testeq = traits_type::eq(traits_type::
+						    to_char_type(__c),
+						    this->gptr()[-1]);	  
+	      const bool __testout = this->_M_mode & ios_base::out;
+	      if (__testeq || __testout)
+		{
+		  this->gbump(-1);
+		  if (!__testeq)
+		    *this->gptr() = traits_type::to_char_type(__c);
+		  __ret = __c;
+		}
+	    }
+	  else
+	    {
+	      this->gbump(-1);
+	      __ret = traits_type::not_eof(__c);
+	    }
+	}
+      return __ret;
+    }
+
+  template <class _CharT, class _Traits, class _Alloc>
+    typename basic_stringbuf<_CharT, _Traits, _Alloc>::int_type
+    basic_stringbuf<_CharT, _Traits, _Alloc>::
+    overflow(int_type __c)
+    {
+      const bool __testout = this->_M_mode & ios_base::out;
+      if (__builtin_expect(!__testout, false))
+	return traits_type::eof();
+
+      const bool __testeof = traits_type::eq_int_type(__c, traits_type::eof());
+      if (__builtin_expect(__testeof, false))
+	return traits_type::not_eof(__c);
+
+      const __size_type __capacity = _M_string.capacity();
+
+#if _GLIBCXX_USE_CXX11_ABI
+      if (size_t(this->epptr() - this->pbase()) < __capacity)
+	{
+	  // There is additional capacity in _M_string that can be used.
+	  char_type* __base = const_cast<char_type*>(_M_string.data());
+	  _M_pbump(__base, __base + __capacity, this->pptr() - this->pbase());
+	  if (_M_mode & ios_base::in)
+	    {
+	      const __size_type __nget = this->gptr() - this->eback();
+	      const __size_type __eget = this->egptr() - this->eback();
+	      this->setg(__base, __base + __nget, __base + __eget + 1);
+	    }
+	  *this->pptr() = traits_type::to_char_type(__c);
+	  this->pbump(1);
+	  return __c;
+	}
+#endif
+
+      const __size_type __max_size = _M_string.max_size();
+      const bool __testput = this->pptr() < this->epptr();
+      if (__builtin_expect(!__testput && __capacity == __max_size, false))
+	return traits_type::eof();
+
+      // Try to append __c into output sequence in one of two ways.
+      // Order these tests done in is unspecified by the standard.
+      const char_type __conv = traits_type::to_char_type(__c);
+      if (!__testput)
+	{
+	  // NB: Start ostringstream buffers at 512 chars.  This is an
+	  // experimental value (pronounced "arbitrary" in some of the
+	  // hipper English-speaking countries), and can be changed to
+	  // suit particular needs.
+	  //
+	  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+	  // 169. Bad efficiency of overflow() mandated
+	  // 432. stringbuf::overflow() makes only one write position
+	  //      available
+	  const __size_type __opt_len = std::max(__size_type(2 * __capacity),
+						 __size_type(512));
+	  const __size_type __len = std::min(__opt_len, __max_size);
+	  __string_type __tmp(_M_string.get_allocator());
+	  __tmp.reserve(__len);
+	  if (this->pbase())
+	    __tmp.assign(this->pbase(), this->epptr() - this->pbase());
+	  __tmp.push_back(__conv);
+	  _M_string.swap(__tmp);
+	  _M_sync(const_cast<char_type*>(_M_string.data()),
+		  this->gptr() - this->eback(), this->pptr() - this->pbase());
+	}
+      else
+	*this->pptr() = __conv;
+      this->pbump(1);
+      return __c;
+    }
+
+  template <class _CharT, class _Traits, class _Alloc>
+    typename basic_stringbuf<_CharT, _Traits, _Alloc>::int_type
+    basic_stringbuf<_CharT, _Traits, _Alloc>::
+    underflow()
+    {
+      int_type __ret = traits_type::eof();
+      const bool __testin = this->_M_mode & ios_base::in;
+      if (__testin)
+	{
+	  // Update egptr() to match the actual string end.
+	  _M_update_egptr();
+
+	  if (this->gptr() < this->egptr())
+	    __ret = traits_type::to_int_type(*this->gptr());
+	}
+      return __ret;
+    }
+
+  template <class _CharT, class _Traits, class _Alloc>
+    typename basic_stringbuf<_CharT, _Traits, _Alloc>::pos_type
+    basic_stringbuf<_CharT, _Traits, _Alloc>::
+    seekoff(off_type __off, ios_base::seekdir __way, ios_base::openmode __mode)
+    {
+      pos_type __ret =  pos_type(off_type(-1));
+      bool __testin = (ios_base::in & this->_M_mode & __mode) != 0;
+      bool __testout = (ios_base::out & this->_M_mode & __mode) != 0;
+      const bool __testboth = __testin && __testout && __way != ios_base::cur;
+      __testin &= !(__mode & ios_base::out);
+      __testout &= !(__mode & ios_base::in);
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 453. basic_stringbuf::seekoff need not always fail for an empty stream.
+      const char_type* __beg = __testin ? this->eback() : this->pbase();
+      if ((__beg || !__off) && (__testin || __testout || __testboth))
+	{
+	  _M_update_egptr();
+
+	  off_type __newoffi = __off;
+	  off_type __newoffo = __newoffi;
+	  if (__way == ios_base::cur)
+	    {
+	      __newoffi += this->gptr() - __beg;
+	      __newoffo += this->pptr() - __beg;
+	    }
+	  else if (__way == ios_base::end)
+	    __newoffo = __newoffi += this->egptr() - __beg;
+
+	  if ((__testin || __testboth)
+	      && __newoffi >= 0
+	      && this->egptr() - __beg >= __newoffi)
+	    {
+	      this->setg(this->eback(), this->eback() + __newoffi,
+			 this->egptr());
+	      __ret = pos_type(__newoffi);
+	    }
+	  if ((__testout || __testboth)
+	      && __newoffo >= 0
+	      && this->egptr() - __beg >= __newoffo)
+	    {
+	      _M_pbump(this->pbase(), this->epptr(), __newoffo);
+	      __ret = pos_type(__newoffo);
+	    }
+	}
+      return __ret;
+    }
+
+  template <class _CharT, class _Traits, class _Alloc>
+    typename basic_stringbuf<_CharT, _Traits, _Alloc>::pos_type
+    basic_stringbuf<_CharT, _Traits, _Alloc>::
+    seekpos(pos_type __sp, ios_base::openmode __mode)
+    {
+      pos_type __ret =  pos_type(off_type(-1));
+      const bool __testin = (ios_base::in & this->_M_mode & __mode) != 0;
+      const bool __testout = (ios_base::out & this->_M_mode & __mode) != 0;
+
+      const char_type* __beg = __testin ? this->eback() : this->pbase();
+      if ((__beg || !off_type(__sp)) && (__testin || __testout))
+	{
+	  _M_update_egptr();
+
+	  const off_type __pos(__sp);
+	  const bool __testpos = (0 <= __pos
+				  && __pos <= this->egptr() - __beg);
+	  if (__testpos)
+	    {
+	      if (__testin)
+		this->setg(this->eback(), this->eback() + __pos,
+			   this->egptr());
+	      if (__testout)
+		_M_pbump(this->pbase(), this->epptr(), __pos);
+	      __ret = __sp;
+	    }
+	}
+      return __ret;
+    }
+
+  template <class _CharT, class _Traits, class _Alloc>
+    void
+    basic_stringbuf<_CharT, _Traits, _Alloc>::
+    _M_sync(char_type* __base, __size_type __i, __size_type __o)
+    {
+      const bool __testin = _M_mode & ios_base::in;
+      const bool __testout = _M_mode & ios_base::out;
+      char_type* __endg = __base + _M_string.size();
+      char_type* __endp = __base + _M_string.capacity();
+
+      if (__base != _M_string.data())
+	{
+	  // setbuf: __i == size of buffer area (_M_string.size() == 0).
+	  __endg += __i;
+	  __i = 0;
+	  __endp = __endg;
+	}
+
+      if (__testin)
+	this->setg(__base, __base + __i, __endg);
+      if (__testout)
+	{
+	  _M_pbump(__base, __endp, __o);
+	  // egptr() always tracks the string end.  When !__testin,
+	  // for the correct functioning of the streambuf inlines
+	  // the other get area pointers are identical.
+	  if (!__testin)
+	    this->setg(__endg, __endg, __endg);
+	}
+    }
+
+  template <class _CharT, class _Traits, class _Alloc>
+    void
+    basic_stringbuf<_CharT, _Traits, _Alloc>::
+    _M_pbump(char_type* __pbeg, char_type* __pend, off_type __off)
+    {
+      this->setp(__pbeg, __pend);
+      while (__off > __gnu_cxx::__numeric_traits<int>::__max)
+	{
+	  this->pbump(__gnu_cxx::__numeric_traits<int>::__max);
+	  __off -= __gnu_cxx::__numeric_traits<int>::__max;
+	}
+      this->pbump(__off);
+    }
+
+  // Inhibit implicit instantiations for required instantiations,
+  // which are defined via explicit instantiations elsewhere.
+#if _GLIBCXX_EXTERN_TEMPLATE
+  extern template class basic_stringbuf<char>;
+  extern template class basic_istringstream<char>;
+  extern template class basic_ostringstream<char>;
+  extern template class basic_stringstream<char>;
+
+#ifdef _GLIBCXX_USE_WCHAR_T
+  extern template class basic_stringbuf<wchar_t>;
+  extern template class basic_istringstream<wchar_t>;
+  extern template class basic_ostringstream<wchar_t>;
+  extern template class basic_stringstream<wchar_t>;
+#endif
+#endif
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@sstream.tcc.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@sstream.tcc.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@std_abs.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@std_abs.h
new file mode 100644
index 0000000000000000000000000000000000000000..c8d589d2b0a4a64320a732a58141f0687a8c7616
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@std_abs.h
@@ -0,0 +1,111 @@
+// -*- C++ -*- C library enhancements header.
+
+// Copyright (C) 2016-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file include/bits/std_abs.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{cmath, cstdlib}
+ */
+
+#ifndef _GLIBCXX_BITS_STD_ABS_H
+#define _GLIBCXX_BITS_STD_ABS_H
+
+#pragma GCC system_header
+
+#include <bits/c++config.h>
+
+#define _GLIBCXX_INCLUDE_NEXT_C_HEADERS
+#include_next <stdlib.h>
+#ifdef __CORRECT_ISO_CPP_MATH_H_PROTO
+# include_next <math.h>
+#endif
+#undef _GLIBCXX_INCLUDE_NEXT_C_HEADERS
+
+#undef abs
+
+extern "C++"
+{
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  using ::abs;
+
+#ifndef __CORRECT_ISO_CPP_STDLIB_H_PROTO
+  inline long
+  abs(long __i) { return __builtin_labs(__i); }
+#endif
+
+#ifdef _GLIBCXX_USE_LONG_LONG
+  inline long long
+  abs(long long __x) { return __builtin_llabs (__x); }
+#endif
+
+// _GLIBCXX_RESOLVE_LIB_DEFECTS
+// 2192. Validity and return type of std::abs(0u) is unclear
+// 2294. <cstdlib> should declare abs(double)
+// 2735. std::abs(short), std::abs(signed char) and others should return int
+
+#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
+  inline _GLIBCXX_CONSTEXPR double
+  abs(double __x)
+  { return __builtin_fabs(__x); }
+
+  inline _GLIBCXX_CONSTEXPR float
+  abs(float __x)
+  { return __builtin_fabsf(__x); }
+
+  inline _GLIBCXX_CONSTEXPR long double
+  abs(long double __x)
+  { return __builtin_fabsl(__x); }
+#endif
+
+#if defined(__GLIBCXX_TYPE_INT_N_0)
+  __extension__ inline _GLIBCXX_CONSTEXPR __GLIBCXX_TYPE_INT_N_0
+  abs(__GLIBCXX_TYPE_INT_N_0 __x) { return __x >= 0 ? __x : -__x; }
+#endif
+#if defined(__GLIBCXX_TYPE_INT_N_1)
+  __extension__ inline _GLIBCXX_CONSTEXPR __GLIBCXX_TYPE_INT_N_1
+  abs(__GLIBCXX_TYPE_INT_N_1 __x) { return __x >= 0 ? __x : -__x; }
+#endif
+#if defined(__GLIBCXX_TYPE_INT_N_2)
+  __extension__ inline _GLIBCXX_CONSTEXPR __GLIBCXX_TYPE_INT_N_2
+  abs(__GLIBCXX_TYPE_INT_N_2 __x) { return __x >= 0 ? __x : -__x; }
+#endif
+#if defined(__GLIBCXX_TYPE_INT_N_3)
+  __extension__ inline _GLIBCXX_CONSTEXPR __GLIBCXX_TYPE_INT_N_3
+  abs(__GLIBCXX_TYPE_INT_N_3 __x) { return __x >= 0 ? __x : -__x; }
+#endif
+
+#if !defined(__STRICT_ANSI__) && defined(_GLIBCXX_USE_FLOAT128)
+  __extension__ inline _GLIBCXX_CONSTEXPR
+  __float128
+  abs(__float128 __x)
+  { return __x < 0 ? -__x : __x; }
+#endif
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+} // extern "C"++"
+
+#endif // _GLIBCXX_BITS_STD_ABS_H
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@std_abs.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@std_abs.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@std_function.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@std_function.h
new file mode 100644
index 0000000000000000000000000000000000000000..96918a04a35d4ae3afd93efad466b526f5c8061b
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@std_function.h
@@ -0,0 +1,778 @@
+// Implementation of std::function -*- C++ -*-
+
+// Copyright (C) 2004-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file include/bits/std_function.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{functional}
+ */
+
+#ifndef _GLIBCXX_STD_FUNCTION_H
+#define _GLIBCXX_STD_FUNCTION_H 1
+
+#pragma GCC system_header
+
+#if __cplusplus < 201103L
+# include <bits/c++0x_warning.h>
+#else
+
+#include <typeinfo>
+#include <bits/stl_function.h>
+#include <bits/invoke.h>
+#include <bits/refwrap.h>
+#include <bits/functexcept.h>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /**
+   *  @brief Exception class thrown when class template function's
+   *  operator() is called with an empty target.
+   *  @ingroup exceptions
+   */
+  class bad_function_call : public std::exception
+  {
+  public:
+    virtual ~bad_function_call() noexcept;
+
+    const char* what() const noexcept;
+  };
+
+  /**
+   *  Trait identifying "location-invariant" types, meaning that the
+   *  address of the object (or any of its members) will not escape.
+   *  Trivially copyable types are location-invariant and users can
+   *  specialize this trait for other types.
+   */
+  template<typename _Tp>
+    struct __is_location_invariant
+    : is_trivially_copyable<_Tp>::type
+    { };
+
+  class _Undefined_class;
+
+  union _Nocopy_types
+  {
+    void*       _M_object;
+    const void* _M_const_object;
+    void (*_M_function_pointer)();
+    void (_Undefined_class::*_M_member_pointer)();
+  };
+
+  union [[gnu::may_alias]] _Any_data
+  {
+    void*       _M_access()       noexcept { return &_M_pod_data[0]; }
+    const void* _M_access() const noexcept { return &_M_pod_data[0]; }
+
+    template<typename _Tp>
+      _Tp&
+      _M_access() noexcept
+      { return *static_cast<_Tp*>(_M_access()); }
+
+    template<typename _Tp>
+      const _Tp&
+      _M_access() const noexcept
+      { return *static_cast<const _Tp*>(_M_access()); }
+
+    _Nocopy_types _M_unused;
+    char _M_pod_data[sizeof(_Nocopy_types)];
+  };
+
+  enum _Manager_operation
+  {
+    __get_type_info,
+    __get_functor_ptr,
+    __clone_functor,
+    __destroy_functor
+  };
+
+  template<typename _Signature>
+    class function;
+
+  /// Base class of all polymorphic function object wrappers.
+  class _Function_base
+  {
+  public:
+    static const size_t _M_max_size = sizeof(_Nocopy_types);
+    static const size_t _M_max_align = __alignof__(_Nocopy_types);
+
+    template<typename _Functor>
+      class _Base_manager
+      {
+      protected:
+	static const bool __stored_locally =
+	(__is_location_invariant<_Functor>::value
+	 && sizeof(_Functor) <= _M_max_size
+	 && __alignof__(_Functor) <= _M_max_align
+	 && (_M_max_align % __alignof__(_Functor) == 0));
+
+	using _Local_storage = integral_constant<bool, __stored_locally>;
+
+	// Retrieve a pointer to the function object
+	static _Functor*
+	_M_get_pointer(const _Any_data& __source) noexcept
+	{
+	  if _GLIBCXX17_CONSTEXPR (__stored_locally)
+	    {
+	      const _Functor& __f = __source._M_access<_Functor>();
+	      return const_cast<_Functor*>(std::__addressof(__f));
+	    }
+	  else // have stored a pointer
+	    return __source._M_access<_Functor*>();
+	}
+
+      private:
+	// Construct a location-invariant function object that fits within
+	// an _Any_data structure.
+	template<typename _Fn>
+	  static void
+	  _M_create(_Any_data& __dest, _Fn&& __f, true_type)
+	  {
+	    ::new (__dest._M_access()) _Functor(std::forward<_Fn>(__f));
+	  }
+
+	// Construct a function object on the heap and store a pointer.
+	template<typename _Fn>
+	  static void
+	  _M_create(_Any_data& __dest, _Fn&& __f, false_type)
+	  {
+	    __dest._M_access<_Functor*>()
+	      = new _Functor(std::forward<_Fn>(__f));
+	  }
+
+	// Destroy an object stored in the internal buffer.
+	static void
+	_M_destroy(_Any_data& __victim, true_type)
+	{
+	  __victim._M_access<_Functor>().~_Functor();
+	}
+
+	// Destroy an object located on the heap.
+	static void
+	_M_destroy(_Any_data& __victim, false_type)
+	{
+	  delete __victim._M_access<_Functor*>();
+	}
+
+      public:
+	static bool
+	_M_manager(_Any_data& __dest, const _Any_data& __source,
+		   _Manager_operation __op)
+	{
+	  switch (__op)
+	    {
+	    case __get_type_info:
+#if __cpp_rtti
+	      __dest._M_access<const type_info*>() = &typeid(_Functor);
+#else
+	      __dest._M_access<const type_info*>() = nullptr;
+#endif
+	      break;
+
+	    case __get_functor_ptr:
+	      __dest._M_access<_Functor*>() = _M_get_pointer(__source);
+	      break;
+
+	    case __clone_functor:
+	      _M_init_functor(__dest,
+		  *const_cast<const _Functor*>(_M_get_pointer(__source)));
+	      break;
+
+	    case __destroy_functor:
+	      _M_destroy(__dest, _Local_storage());
+	      break;
+	    }
+	  return false;
+	}
+
+	template<typename _Fn>
+	  static void
+	  _M_init_functor(_Any_data& __functor, _Fn&& __f)
+	  noexcept(__and_<_Local_storage,
+			  is_nothrow_constructible<_Functor, _Fn>>::value)
+	  {
+	    _M_create(__functor, std::forward<_Fn>(__f), _Local_storage());
+	  }
+
+	template<typename _Signature>
+	  static bool
+	  _M_not_empty_function(const function<_Signature>& __f) noexcept
+	  { return static_cast<bool>(__f); }
+
+	template<typename _Tp>
+	  static bool
+	  _M_not_empty_function(_Tp* __fp) noexcept
+	  { return __fp != nullptr; }
+
+	template<typename _Class, typename _Tp>
+	  static bool
+	  _M_not_empty_function(_Tp _Class::* __mp) noexcept
+	  { return __mp != nullptr; }
+
+	template<typename _Tp>
+	  static bool
+	  _M_not_empty_function(const _Tp&) noexcept
+	  { return true; }
+      };
+
+    _Function_base() = default;
+
+    ~_Function_base()
+    {
+      if (_M_manager)
+	_M_manager(_M_functor, _M_functor, __destroy_functor);
+    }
+
+    bool _M_empty() const { return !_M_manager; }
+
+    using _Manager_type
+      = bool (*)(_Any_data&, const _Any_data&, _Manager_operation);
+
+    _Any_data     _M_functor{};
+    _Manager_type _M_manager{};
+  };
+
+  template<typename _Signature, typename _Functor>
+    class _Function_handler;
+
+  template<typename _Res, typename _Functor, typename... _ArgTypes>
+    class _Function_handler<_Res(_ArgTypes...), _Functor>
+    : public _Function_base::_Base_manager<_Functor>
+    {
+      using _Base = _Function_base::_Base_manager<_Functor>;
+
+    public:
+      static bool
+      _M_manager(_Any_data& __dest, const _Any_data& __source,
+		 _Manager_operation __op)
+      {
+	switch (__op)
+	  {
+#if __cpp_rtti
+	  case __get_type_info:
+	    __dest._M_access<const type_info*>() = &typeid(_Functor);
+	    break;
+#endif
+	  case __get_functor_ptr:
+	    __dest._M_access<_Functor*>() = _Base::_M_get_pointer(__source);
+	    break;
+
+	  default:
+	    _Base::_M_manager(__dest, __source, __op);
+	  }
+	return false;
+      }
+
+      static _Res
+      _M_invoke(const _Any_data& __functor, _ArgTypes&&... __args)
+      {
+	return std::__invoke_r<_Res>(*_Base::_M_get_pointer(__functor),
+				     std::forward<_ArgTypes>(__args)...);
+      }
+
+      template<typename _Fn>
+	static constexpr bool
+	_S_nothrow_init() noexcept
+	{
+	  return __and_<typename _Base::_Local_storage,
+			is_nothrow_constructible<_Functor, _Fn>>::value;
+	}
+    };
+
+  // Specialization for invalid types
+  template<>
+    class _Function_handler<void, void>
+    {
+    public:
+      static bool
+      _M_manager(_Any_data&, const _Any_data&, _Manager_operation)
+      { return false; }
+    };
+
+  // Avoids instantiating ill-formed specializations of _Function_handler
+  // in std::function<_Signature>::target<_Functor>().
+  // e.g. _Function_handler<Sig, void()> and _Function_handler<Sig, void>
+  // would be ill-formed.
+  template<typename _Signature, typename _Functor,
+	   bool __valid = is_object<_Functor>::value>
+    struct _Target_handler
+    : _Function_handler<_Signature, typename remove_cv<_Functor>::type>
+    { };
+
+  template<typename _Signature, typename _Functor>
+    struct _Target_handler<_Signature, _Functor, false>
+    : _Function_handler<void, void>
+    { };
+
+  /**
+   *  @brief Polymorphic function wrapper.
+   *  @ingroup functors
+   *  @since C++11
+   */
+  template<typename _Res, typename... _ArgTypes>
+    class function<_Res(_ArgTypes...)>
+    : public _Maybe_unary_or_binary_function<_Res, _ArgTypes...>,
+      private _Function_base
+    {
+      // Equivalent to std::decay_t except that it produces an invalid type
+      // if the decayed type is the current specialization of std::function.
+      template<typename _Func,
+	       bool _Self = is_same<__remove_cvref_t<_Func>, function>::value>
+	using _Decay_t
+	  = typename __enable_if_t<!_Self, decay<_Func>>::type;
+
+      template<typename _Func,
+	       typename _DFunc = _Decay_t<_Func>,
+	       typename _Res2 = __invoke_result<_DFunc&, _ArgTypes...>>
+	struct _Callable
+	: __is_invocable_impl<_Res2, _Res>::type
+	{ };
+
+      template<typename _Cond, typename _Tp = void>
+	using _Requires = __enable_if_t<_Cond::value, _Tp>;
+
+      template<typename _Functor>
+	using _Handler
+	  = _Function_handler<_Res(_ArgTypes...), __decay_t<_Functor>>;
+
+    public:
+      typedef _Res result_type;
+
+      // [3.7.2.1] construct/copy/destroy
+
+      /**
+       *  @brief Default construct creates an empty function call wrapper.
+       *  @post `!(bool)*this`
+       */
+      function() noexcept
+      : _Function_base() { }
+
+      /**
+       *  @brief Creates an empty function call wrapper.
+       *  @post @c !(bool)*this
+       */
+      function(nullptr_t) noexcept
+      : _Function_base() { }
+
+      /**
+       *  @brief %Function copy constructor.
+       *  @param __x A %function object with identical call signature.
+       *  @post `bool(*this) == bool(__x)`
+       *
+       *  The newly-created %function contains a copy of the target of
+       *  `__x` (if it has one).
+       */
+      function(const function& __x)
+      : _Function_base()
+      {
+	if (static_cast<bool>(__x))
+	  {
+	    __x._M_manager(_M_functor, __x._M_functor, __clone_functor);
+	    _M_invoker = __x._M_invoker;
+	    _M_manager = __x._M_manager;
+	  }
+      }
+
+      /**
+       *  @brief %Function move constructor.
+       *  @param __x A %function object rvalue with identical call signature.
+       *
+       *  The newly-created %function contains the target of `__x`
+       *  (if it has one).
+       */
+      function(function&& __x) noexcept
+      : _Function_base(), _M_invoker(__x._M_invoker)
+      {
+	if (static_cast<bool>(__x))
+	  {
+	    _M_functor = __x._M_functor;
+	    _M_manager = __x._M_manager;
+	    __x._M_manager = nullptr;
+	    __x._M_invoker = nullptr;
+	  }
+      }
+
+      /**
+       *  @brief Builds a %function that targets a copy of the incoming
+       *  function object.
+       *  @param __f A %function object that is callable with parameters of
+       *  type `ArgTypes...` and returns a value convertible to `Res`.
+       *
+       *  The newly-created %function object will target a copy of
+       *  `__f`. If `__f` is `reference_wrapper<F>`, then this function
+       *  object will contain a reference to the function object `__f.get()`.
+       *  If `__f` is a null function pointer, null pointer-to-member, or
+       *  empty `std::function`, the newly-created object will be empty.
+       *
+       *  If `__f` is a non-null function pointer or an object of type
+       *  `reference_wrapper<F>`, this function will not throw.
+       */
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 2774. std::function construction vs assignment
+      template<typename _Functor,
+	       typename _Constraints = _Requires<_Callable<_Functor>>>
+	function(_Functor&& __f)
+	noexcept(_Handler<_Functor>::template _S_nothrow_init<_Functor>())
+	: _Function_base()
+	{
+	  static_assert(is_copy_constructible<__decay_t<_Functor>>::value,
+	      "std::function target must be copy-constructible");
+	  static_assert(is_constructible<__decay_t<_Functor>, _Functor>::value,
+	      "std::function target must be constructible from the "
+	      "constructor argument");
+
+	  using _My_handler = _Handler<_Functor>;
+
+	  if (_My_handler::_M_not_empty_function(__f))
+	    {
+	      _My_handler::_M_init_functor(_M_functor,
+					   std::forward<_Functor>(__f));
+	      _M_invoker = &_My_handler::_M_invoke;
+	      _M_manager = &_My_handler::_M_manager;
+	    }
+	}
+
+      /**
+       *  @brief Function assignment operator.
+       *  @param __x A %function with identical call signature.
+       *  @post `(bool)*this == (bool)x`
+       *  @returns `*this`
+       *
+       *  The target of `__x` is copied to `*this`. If `__x` has no
+       *  target, then `*this` will be empty.
+       *
+       *  If `__x` targets a function pointer or a reference to a function
+       *  object, then this operation will not throw an exception.
+       */
+      function&
+      operator=(const function& __x)
+      {
+	function(__x).swap(*this);
+	return *this;
+      }
+
+      /**
+       *  @brief Function move-assignment operator.
+       *  @param __x A %function rvalue with identical call signature.
+       *  @returns `*this`
+       *
+       *  The target of `__x` is moved to `*this`. If `__x` has no
+       *  target, then `*this` will be empty.
+       *
+       *  If `__x` targets a function pointer or a reference to a function
+       *  object, then this operation will not throw an exception.
+       */
+      function&
+      operator=(function&& __x) noexcept
+      {
+	function(std::move(__x)).swap(*this);
+	return *this;
+      }
+
+      /**
+       *  @brief Function assignment to empty.
+       *  @post `!(bool)*this`
+       *  @returns `*this`
+       *
+       *  The target of `*this` is deallocated, leaving it empty.
+       */
+      function&
+      operator=(nullptr_t) noexcept
+      {
+	if (_M_manager)
+	  {
+	    _M_manager(_M_functor, _M_functor, __destroy_functor);
+	    _M_manager = nullptr;
+	    _M_invoker = nullptr;
+	  }
+	return *this;
+      }
+
+      /**
+       *  @brief Function assignment to a new target.
+       *  @param __f  A function object that is callable with parameters of
+       *              type  `_ArgTypes...` and returns a value convertible
+       *              to `_Res`.
+       *  @return `*this`
+       *  @since C++11
+       *
+       *  This function object wrapper will target a copy of `__f`. If `__f`
+       *  is `reference_wrapper<F>`, then this function object will contain
+       *  a reference to the function object `__f.get()`. If `__f` is a null
+       *  function pointer or null pointer-to-member, this object will be
+       *  empty.
+       *
+       *  If `__f` is a non-null function pointer or an object of type
+       *  `reference_wrapper<F>`, this function will not throw.
+       */
+      template<typename _Functor>
+	_Requires<_Callable<_Functor>, function&>
+	operator=(_Functor&& __f)
+	noexcept(_Handler<_Functor>::template _S_nothrow_init<_Functor>())
+	{
+	  function(std::forward<_Functor>(__f)).swap(*this);
+	  return *this;
+	}
+
+      /// @overload
+      template<typename _Functor>
+	function&
+	operator=(reference_wrapper<_Functor> __f) noexcept
+	{
+	  function(__f).swap(*this);
+	  return *this;
+	}
+
+      // [3.7.2.2] function modifiers
+
+      /**
+       *  @brief Swap the targets of two %function objects.
+       *  @param __x A %function with identical call signature.
+       *
+       *  Swap the targets of `this` function object and `__f`.
+       *  This function will not throw exceptions.
+       */
+      void swap(function& __x) noexcept
+      {
+	std::swap(_M_functor, __x._M_functor);
+	std::swap(_M_manager, __x._M_manager);
+	std::swap(_M_invoker, __x._M_invoker);
+      }
+
+      // [3.7.2.3] function capacity
+
+      /**
+       *  @brief Determine if the %function wrapper has a target.
+       *
+       *  @return `true` when this function object contains a target,
+       *  or `false` when it is empty.
+       *
+       *  This function will not throw exceptions.
+       */
+      explicit operator bool() const noexcept
+      { return !_M_empty(); }
+
+      // [3.7.2.4] function invocation
+
+      /**
+       *  @brief Invokes the function targeted by `*this`.
+       *  @returns the result of the target.
+       *  @throws `bad_function_call` when `!(bool)*this`
+       *
+       *  The function call operator invokes the target function object
+       *  stored by `this`.
+       */
+      _Res
+      operator()(_ArgTypes... __args) const
+      {
+	if (_M_empty())
+	  __throw_bad_function_call();
+	return _M_invoker(_M_functor, std::forward<_ArgTypes>(__args)...);
+      }
+
+#if __cpp_rtti
+      // [3.7.2.5] function target access
+      /**
+       *  @brief Determine the type of the target of this function object
+       *  wrapper.
+       *
+       *  @returns the type identifier of the target function object, or
+       *  `typeid(void)` if `!(bool)*this`.
+       *
+       *  This function will not throw exceptions.
+       */
+      const type_info&
+      target_type() const noexcept
+      {
+	if (_M_manager)
+	  {
+	    _Any_data __typeinfo_result;
+	    _M_manager(__typeinfo_result, _M_functor, __get_type_info);
+	    if (auto __ti =  __typeinfo_result._M_access<const type_info*>())
+	      return *__ti;
+	  }
+	return typeid(void);
+      }
+#endif
+
+      /**
+       *  @brief Access the stored target function object.
+       *
+       *  @return Returns a pointer to the stored target function object,
+       *  if `typeid(_Functor).equals(target_type())`; otherwise, a null
+       *  pointer.
+       *
+       * This function does not throw exceptions.
+       *
+       * @{
+       */
+      template<typename _Functor>
+	_Functor*
+	target() noexcept
+	{
+	  const function* __const_this = this;
+	  const _Functor* __func = __const_this->template target<_Functor>();
+	  // If is_function_v<_Functor> is true then const_cast<_Functor*>
+	  // would be ill-formed, so use *const_cast<_Functor**> instead.
+	  return *const_cast<_Functor**>(&__func);
+	}
+
+      template<typename _Functor>
+	const _Functor*
+	target() const noexcept
+	{
+	  if _GLIBCXX17_CONSTEXPR (is_object<_Functor>::value)
+	    {
+	      // For C++11 and C++14 if-constexpr is not used above, so
+	      // _Target_handler avoids ill-formed _Function_handler types.
+	      using _Handler = _Target_handler<_Res(_ArgTypes...), _Functor>;
+
+	      if (_M_manager == &_Handler::_M_manager
+#if __cpp_rtti
+		  || (_M_manager && typeid(_Functor) == target_type())
+#endif
+		 )
+		{
+		  _Any_data __ptr;
+		  _M_manager(__ptr, _M_functor, __get_functor_ptr);
+		  return __ptr._M_access<const _Functor*>();
+		}
+	    }
+	  return nullptr;
+	}
+      /// @}
+
+    private:
+      using _Invoker_type = _Res (*)(const _Any_data&, _ArgTypes&&...);
+      _Invoker_type _M_invoker = nullptr;
+    };
+
+#if __cpp_deduction_guides >= 201606
+  template<typename>
+    struct __function_guide_helper
+    { };
+
+  template<typename _Res, typename _Tp, bool _Nx, typename... _Args>
+    struct __function_guide_helper<
+      _Res (_Tp::*) (_Args...) noexcept(_Nx)
+    >
+    { using type = _Res(_Args...); };
+
+  template<typename _Res, typename _Tp, bool _Nx, typename... _Args>
+    struct __function_guide_helper<
+      _Res (_Tp::*) (_Args...) & noexcept(_Nx)
+    >
+    { using type = _Res(_Args...); };
+
+  template<typename _Res, typename _Tp, bool _Nx, typename... _Args>
+    struct __function_guide_helper<
+      _Res (_Tp::*) (_Args...) const noexcept(_Nx)
+    >
+    { using type = _Res(_Args...); };
+
+  template<typename _Res, typename _Tp, bool _Nx, typename... _Args>
+    struct __function_guide_helper<
+      _Res (_Tp::*) (_Args...) const & noexcept(_Nx)
+    >
+    { using type = _Res(_Args...); };
+
+  template<typename _Res, typename... _ArgTypes>
+    function(_Res(*)(_ArgTypes...)) -> function<_Res(_ArgTypes...)>;
+
+  template<typename _Functor, typename _Signature = typename
+	   __function_guide_helper<decltype(&_Functor::operator())>::type>
+    function(_Functor) -> function<_Signature>;
+#endif
+
+  // [20.7.15.2.6] null pointer comparisons
+
+  /**
+   *  @brief Test whether a polymorphic function object wrapper is empty.
+   *  @returns `true` if the wrapper has no target, `false` otherwise
+   *
+   *  This function will not throw exceptions.
+   */
+  template<typename _Res, typename... _Args>
+    inline bool
+    operator==(const function<_Res(_Args...)>& __f, nullptr_t) noexcept
+    { return !static_cast<bool>(__f); }
+
+#if __cpp_impl_three_way_comparison < 201907L
+  /// @overload
+  template<typename _Res, typename... _Args>
+    inline bool
+    operator==(nullptr_t, const function<_Res(_Args...)>& __f) noexcept
+    { return !static_cast<bool>(__f); }
+
+  /**
+   *  @brief Test whether a polymorphic function object wrapper is non-empty.
+   *  @returns `false` if the wrapper has no target, `true` otherwise
+   *
+   *  This function will not throw exceptions.
+   */
+  template<typename _Res, typename... _Args>
+    inline bool
+    operator!=(const function<_Res(_Args...)>& __f, nullptr_t) noexcept
+    { return static_cast<bool>(__f); }
+
+  /// @overload
+  template<typename _Res, typename... _Args>
+    inline bool
+    operator!=(nullptr_t, const function<_Res(_Args...)>& __f) noexcept
+    { return static_cast<bool>(__f); }
+#endif
+
+  // [20.7.15.2.7] specialized algorithms
+
+  /**
+   *  @brief Swap the targets of two polymorphic function object wrappers.
+   *
+   *  This function will not throw exceptions.
+   */
+  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+  // 2062. Effect contradictions w/o no-throw guarantee of std::function swaps
+  template<typename _Res, typename... _Args>
+    inline void
+    swap(function<_Res(_Args...)>& __x, function<_Res(_Args...)>& __y) noexcept
+    { __x.swap(__y); }
+
+#if __cplusplus >= 201703L
+  namespace __detail::__variant
+  {
+    template<typename> struct _Never_valueless_alt; // see <variant>
+
+    // Provide the strong exception-safety guarantee when emplacing a
+    // function into a variant.
+    template<typename _Signature>
+      struct _Never_valueless_alt<std::function<_Signature>>
+      : std::true_type
+      { };
+  }  // namespace __detail::__variant
+#endif // C++17
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif // C++11
+#endif // _GLIBCXX_STD_FUNCTION_H
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@std_function.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@std_function.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@std_mutex.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@std_mutex.h
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@std_mutex.h
@@ -0,0 +1,248 @@
+// std::mutex implementation -*- C++ -*-
+
+// Copyright (C) 2003-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/std_mutex.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{mutex}
+ */
+
+#ifndef _GLIBCXX_MUTEX_H
+#define _GLIBCXX_MUTEX_H 1
+
+#pragma GCC system_header
+
+#if __cplusplus < 201103L
+# include <bits/c++0x_warning.h>
+#else
+
+#include <system_error>
+#include <bits/functexcept.h>
+#include <bits/gthr.h>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /**
+   * @defgroup mutexes Mutexes
+   * @ingroup concurrency
+   *
+   * Classes for mutex support.
+   * @{
+   */
+
+#ifdef _GLIBCXX_HAS_GTHREADS
+  // Common base class for std::mutex and std::timed_mutex
+  class __mutex_base
+  {
+  protected:
+    typedef __gthread_mutex_t			__native_type;
+
+#ifdef __GTHREAD_MUTEX_INIT
+    __native_type  _M_mutex = __GTHREAD_MUTEX_INIT;
+
+    constexpr __mutex_base() noexcept = default;
+#else
+    __native_type  _M_mutex;
+
+    __mutex_base() noexcept
+    {
+      // XXX EAGAIN, ENOMEM, EPERM, EBUSY(may), EINVAL(may)
+      __GTHREAD_MUTEX_INIT_FUNCTION(&_M_mutex);
+    }
+
+    ~__mutex_base() noexcept { __gthread_mutex_destroy(&_M_mutex); }
+#endif
+
+    __mutex_base(const __mutex_base&) = delete;
+    __mutex_base& operator=(const __mutex_base&) = delete;
+  };
+
+  /// The standard mutex type.
+  class mutex : private __mutex_base
+  {
+  public:
+    typedef __native_type* 			native_handle_type;
+
+#ifdef __GTHREAD_MUTEX_INIT
+    constexpr
+#endif
+    mutex() noexcept = default;
+    ~mutex() = default;
+
+    mutex(const mutex&) = delete;
+    mutex& operator=(const mutex&) = delete;
+
+    void
+    lock()
+    {
+      int __e = __gthread_mutex_lock(&_M_mutex);
+
+      // EINVAL, EAGAIN, EBUSY, EINVAL, EDEADLK(may)
+      if (__e)
+	__throw_system_error(__e);
+    }
+
+    bool
+    try_lock() noexcept
+    {
+      // XXX EINVAL, EAGAIN, EBUSY
+      return !__gthread_mutex_trylock(&_M_mutex);
+    }
+
+    void
+    unlock()
+    {
+      // XXX EINVAL, EAGAIN, EPERM
+      __gthread_mutex_unlock(&_M_mutex);
+    }
+
+    native_handle_type
+    native_handle() noexcept
+    { return &_M_mutex; }
+  };
+
+  // Implementation details for std::condition_variable
+  class __condvar
+  {
+    using timespec = __gthread_time_t;
+
+  public:
+    __condvar() noexcept
+    {
+#ifndef __GTHREAD_COND_INIT
+      __GTHREAD_COND_INIT_FUNCTION(&_M_cond);
+#endif
+    }
+
+    ~__condvar()
+    {
+      int __e __attribute__((__unused__)) = __gthread_cond_destroy(&_M_cond);
+      __glibcxx_assert(__e != EBUSY); // threads are still blocked
+    }
+
+    __condvar(const __condvar&) = delete;
+    __condvar& operator=(const __condvar&) = delete;
+
+    __gthread_cond_t* native_handle() noexcept { return &_M_cond; }
+
+    // Expects: Calling thread has locked __m.
+    void
+    wait(mutex& __m)
+    {
+      int __e __attribute__((__unused__))
+	= __gthread_cond_wait(&_M_cond, __m.native_handle());
+      __glibcxx_assert(__e == 0);
+    }
+
+    void
+    wait_until(mutex& __m, timespec& __abs_time)
+    {
+      __gthread_cond_timedwait(&_M_cond, __m.native_handle(), &__abs_time);
+    }
+
+#ifdef _GLIBCXX_USE_PTHREAD_COND_CLOCKWAIT
+    void
+    wait_until(mutex& __m, clockid_t __clock, timespec& __abs_time)
+    {
+      pthread_cond_clockwait(&_M_cond, __m.native_handle(), __clock,
+			     &__abs_time);
+    }
+#endif
+
+    void
+    notify_one() noexcept
+    {
+      int __e __attribute__((__unused__)) = __gthread_cond_signal(&_M_cond);
+      __glibcxx_assert(__e == 0);
+    }
+
+    void
+    notify_all() noexcept
+    {
+      int __e __attribute__((__unused__)) = __gthread_cond_broadcast(&_M_cond);
+      __glibcxx_assert(__e == 0);
+    }
+
+  protected:
+#ifdef __GTHREAD_COND_INIT
+    __gthread_cond_t _M_cond = __GTHREAD_COND_INIT;
+#else
+    __gthread_cond_t _M_cond;
+#endif
+  };
+
+#endif // _GLIBCXX_HAS_GTHREADS
+
+  /// Do not acquire ownership of the mutex.
+  struct defer_lock_t { explicit defer_lock_t() = default; };
+
+  /// Try to acquire ownership of the mutex without blocking.
+  struct try_to_lock_t { explicit try_to_lock_t() = default; };
+
+  /// Assume the calling thread has already obtained mutex ownership
+  /// and manage it.
+  struct adopt_lock_t { explicit adopt_lock_t() = default; };
+
+  /// Tag used to prevent a scoped lock from acquiring ownership of a mutex.
+  _GLIBCXX17_INLINE constexpr defer_lock_t	defer_lock { };
+
+  /// Tag used to prevent a scoped lock from blocking if a mutex is locked.
+  _GLIBCXX17_INLINE constexpr try_to_lock_t	try_to_lock { };
+
+  /// Tag used to make a scoped lock take ownership of a locked mutex.
+  _GLIBCXX17_INLINE constexpr adopt_lock_t	adopt_lock { };
+
+  /** @brief A simple scoped lock type.
+   *
+   * A lock_guard controls mutex ownership within a scope, releasing
+   * ownership in the destructor.
+   */
+  template<typename _Mutex>
+    class lock_guard
+    {
+    public:
+      typedef _Mutex mutex_type;
+
+      explicit lock_guard(mutex_type& __m) : _M_device(__m)
+      { _M_device.lock(); }
+
+      lock_guard(mutex_type& __m, adopt_lock_t) noexcept : _M_device(__m)
+      { } // calling thread owns mutex
+
+      ~lock_guard()
+      { _M_device.unlock(); }
+
+      lock_guard(const lock_guard&) = delete;
+      lock_guard& operator=(const lock_guard&) = delete;
+
+    private:
+      mutex_type&  _M_device;
+    };
+
+  /// @} group mutexes
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+#endif // C++11
+#endif // _GLIBCXX_MUTEX_H
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@std_thread.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@std_thread.h
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index 0000000000000000000000000000000000000000..dd625de3bc3ed31cfef3c42692c13d1c3ec74232
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@std_thread.h
@@ -0,0 +1,334 @@
+// std::thread declarations -*- C++ -*-
+
+// Copyright (C) 2008-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/std_thread.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{thread}
+ */
+
+#ifndef _GLIBCXX_THREAD_H
+#define _GLIBCXX_THREAD_H 1
+
+#pragma GCC system_header
+
+#if __cplusplus >= 201103L
+#include <bits/c++config.h>
+
+#include <iosfwd>		// std::basic_ostream
+#include <tuple>		// std::tuple
+#include <bits/functional_hash.h> // std::hash
+#include <bits/invoke.h>	// std::__invoke
+#include <bits/refwrap.h>       // not required, but helpful to users
+#include <bits/unique_ptr.h>	// std::unique_ptr
+
+#ifdef _GLIBCXX_HAS_GTHREADS
+# include <bits/gthr.h>
+#else
+# include <errno.h>
+# include <bits/functexcept.h>
+#endif
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /** @addtogroup threads
+   *  @{
+   */
+
+  /// thread
+  class thread
+  {
+  public:
+#ifdef _GLIBCXX_HAS_GTHREADS
+    // Abstract base class for types that wrap arbitrary functors to be
+    // invoked in the new thread of execution.
+    struct _State
+    {
+      virtual ~_State();
+      virtual void _M_run() = 0;
+    };
+    using _State_ptr = unique_ptr<_State>;
+
+    using native_handle_type = __gthread_t;
+#else
+    using native_handle_type = int;
+#endif
+
+    /// thread::id
+    class id
+    {
+      native_handle_type	_M_thread;
+
+    public:
+      id() noexcept : _M_thread() { }
+
+      explicit
+      id(native_handle_type __id) : _M_thread(__id) { }
+
+    private:
+      friend class thread;
+      friend struct hash<id>;
+
+      friend bool
+      operator==(id __x, id __y) noexcept;
+
+#if __cpp_lib_three_way_comparison
+      friend strong_ordering
+      operator<=>(id __x, id __y) noexcept;
+#else
+      friend bool
+      operator<(id __x, id __y) noexcept;
+#endif
+
+      template<class _CharT, class _Traits>
+	friend basic_ostream<_CharT, _Traits>&
+	operator<<(basic_ostream<_CharT, _Traits>& __out, id __id);
+    };
+
+  private:
+    id				_M_id;
+
+    // _GLIBCXX_RESOLVE_LIB_DEFECTS
+    // 2097.  packaged_task constructors should be constrained
+    // 3039. Unnecessary decay in thread and packaged_task
+    template<typename _Tp>
+      using __not_same = __not_<is_same<__remove_cvref_t<_Tp>, thread>>;
+
+  public:
+    thread() noexcept = default;
+
+#ifdef _GLIBCXX_HAS_GTHREADS
+    template<typename _Callable, typename... _Args,
+	     typename = _Require<__not_same<_Callable>>>
+      explicit
+      thread(_Callable&& __f, _Args&&... __args)
+      {
+	static_assert( __is_invocable<typename decay<_Callable>::type,
+				      typename decay<_Args>::type...>::value,
+	  "std::thread arguments must be invocable after conversion to rvalues"
+	  );
+
+#ifdef GTHR_ACTIVE_PROXY
+	// Create a reference to pthread_create, not just the gthr weak symbol.
+	auto __depend = reinterpret_cast<void(*)()>(&pthread_create);
+#else
+	auto __depend = nullptr;
+#endif
+	using _Wrapper = _Call_wrapper<_Callable, _Args...>;
+	// Create a call wrapper with DECAY_COPY(__f) as its target object
+	// and DECAY_COPY(__args)... as its bound argument entities.
+	_M_start_thread(_State_ptr(new _State_impl<_Wrapper>(
+	      std::forward<_Callable>(__f), std::forward<_Args>(__args)...)),
+	    __depend);
+      }
+#endif // _GLIBCXX_HAS_GTHREADS
+
+    ~thread()
+    {
+      if (joinable())
+	std::__terminate();
+    }
+
+    thread(const thread&) = delete;
+
+    thread(thread&& __t) noexcept
+    { swap(__t); }
+
+    thread& operator=(const thread&) = delete;
+
+    thread& operator=(thread&& __t) noexcept
+    {
+      if (joinable())
+	std::__terminate();
+      swap(__t);
+      return *this;
+    }
+
+    void
+    swap(thread& __t) noexcept
+    { std::swap(_M_id, __t._M_id); }
+
+    bool
+    joinable() const noexcept
+    { return !(_M_id == id()); }
+
+    void
+    join();
+
+    void
+    detach();
+
+    id
+    get_id() const noexcept
+    { return _M_id; }
+
+    /** @pre thread is joinable
+     */
+    native_handle_type
+    native_handle()
+    { return _M_id._M_thread; }
+
+    // Returns a value that hints at the number of hardware thread contexts.
+    static unsigned int
+    hardware_concurrency() noexcept;
+
+#ifdef _GLIBCXX_HAS_GTHREADS
+  private:
+    template<typename _Callable>
+      struct _State_impl : public _State
+      {
+	_Callable		_M_func;
+
+	template<typename... _Args>
+	  _State_impl(_Args&&... __args)
+	  : _M_func{{std::forward<_Args>(__args)...}}
+	  { }
+
+	void
+	_M_run() { _M_func(); }
+      };
+
+    void
+    _M_start_thread(_State_ptr, void (*)());
+
+#if _GLIBCXX_THREAD_ABI_COMPAT
+  public:
+    struct _Impl_base;
+    typedef shared_ptr<_Impl_base>	__shared_base_type;
+    struct _Impl_base
+    {
+      __shared_base_type	_M_this_ptr;
+      virtual ~_Impl_base() = default;
+      virtual void _M_run() = 0;
+    };
+
+  private:
+    void
+    _M_start_thread(__shared_base_type, void (*)());
+
+    void
+    _M_start_thread(__shared_base_type);
+#endif
+
+  private:
+    // A call wrapper that does INVOKE(forwarded tuple elements...)
+    template<typename _Tuple>
+      struct _Invoker
+      {
+	_Tuple _M_t;
+
+	template<typename>
+	  struct __result;
+	template<typename _Fn, typename... _Args>
+	  struct __result<tuple<_Fn, _Args...>>
+	  : __invoke_result<_Fn, _Args...>
+	  { };
+
+	template<size_t... _Ind>
+	  typename __result<_Tuple>::type
+	  _M_invoke(_Index_tuple<_Ind...>)
+	  { return std::__invoke(std::get<_Ind>(std::move(_M_t))...); }
+
+	typename __result<_Tuple>::type
+	operator()()
+	{
+	  using _Indices
+	    = typename _Build_index_tuple<tuple_size<_Tuple>::value>::__type;
+	  return _M_invoke(_Indices());
+	}
+      };
+
+  public:
+    template<typename... _Tp>
+      using _Call_wrapper = _Invoker<tuple<typename decay<_Tp>::type...>>;
+#endif // _GLIBCXX_HAS_GTHREADS
+  };
+
+#ifndef _GLIBCXX_HAS_GTHREADS
+  inline void thread::join() { std::__throw_system_error(EINVAL); }
+  inline void thread::detach() { std::__throw_system_error(EINVAL); }
+  inline unsigned int thread::hardware_concurrency() noexcept { return 0; }
+#endif
+
+  inline void
+  swap(thread& __x, thread& __y) noexcept
+  { __x.swap(__y); }
+
+  inline bool
+  operator==(thread::id __x, thread::id __y) noexcept
+  {
+    // pthread_equal is undefined if either thread ID is not valid, so we
+    // can't safely use __gthread_equal on default-constructed values (nor
+    // the non-zero value returned by this_thread::get_id() for
+    // single-threaded programs using GNU libc). Assume EqualityComparable.
+    return __x._M_thread == __y._M_thread;
+  }
+
+  // N.B. other comparison operators are defined in <thread>
+
+  // DR 889.
+  /// std::hash specialization for thread::id.
+  template<>
+    struct hash<thread::id>
+    : public __hash_base<size_t, thread::id>
+    {
+      size_t
+      operator()(const thread::id& __id) const noexcept
+      { return std::_Hash_impl::hash(__id._M_thread); }
+    };
+
+  namespace this_thread
+  {
+    /// this_thread::get_id
+    inline thread::id
+    get_id() noexcept
+    {
+#ifndef _GLIBCXX_HAS_GTHREADS
+      return thread::id(1);
+#elif defined _GLIBCXX_NATIVE_THREAD_ID
+      return thread::id(_GLIBCXX_NATIVE_THREAD_ID);
+#else
+      return thread::id(__gthread_self());
+#endif
+    }
+
+    /// this_thread::yield
+    inline void
+    yield() noexcept
+    {
+#if defined _GLIBCXX_HAS_GTHREADS && defined _GLIBCXX_USE_SCHED_YIELD
+      __gthread_yield();
+#endif
+    }
+
+  } // namespace this_thread
+
+  /// @}
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+#endif // C++11
+
+#endif // _GLIBCXX_THREAD_H
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@std_thread.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@std_thread.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stl_algo.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stl_algo.h
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--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stl_algo.h
@@ -0,0 +1,5896 @@
+// Algorithm implementation -*- C++ -*-
+
+// Copyright (C) 2001-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/*
+ *
+ * Copyright (c) 1994
+ * Hewlett-Packard Company
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Hewlett-Packard Company makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ *
+ *
+ * Copyright (c) 1996
+ * Silicon Graphics Computer Systems, Inc.
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Silicon Graphics makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ */
+
+/** @file bits/stl_algo.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{algorithm}
+ */
+
+#ifndef _STL_ALGO_H
+#define _STL_ALGO_H 1
+
+#include <bits/algorithmfwd.h>
+#include <bits/stl_heap.h>
+#include <bits/stl_tempbuf.h>  // for _Temporary_buffer
+#include <bits/predefined_ops.h>
+
+#if __cplusplus >= 201103L
+#include <bits/uniform_int_dist.h>
+#endif
+
+#if _GLIBCXX_HOSTED && (__cplusplus <= 201103L || _GLIBCXX_USE_DEPRECATED)
+#include <cstdlib>	     // for rand
+#endif
+
+// See concept_check.h for the __glibcxx_*_requires macros.
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /// Swaps the median value of *__a, *__b and *__c under __comp to *__result
+  template<typename _Iterator, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    void
+    __move_median_to_first(_Iterator __result,_Iterator __a, _Iterator __b,
+			   _Iterator __c, _Compare __comp)
+    {
+      if (__comp(__a, __b))
+	{
+	  if (__comp(__b, __c))
+	    std::iter_swap(__result, __b);
+	  else if (__comp(__a, __c))
+	    std::iter_swap(__result, __c);
+	  else
+	    std::iter_swap(__result, __a);
+	}
+      else if (__comp(__a, __c))
+	std::iter_swap(__result, __a);
+      else if (__comp(__b, __c))
+	std::iter_swap(__result, __c);
+      else
+	std::iter_swap(__result, __b);
+    }
+
+  /// Provided for stable_partition to use.
+  template<typename _InputIterator, typename _Predicate>
+    _GLIBCXX20_CONSTEXPR
+    inline _InputIterator
+    __find_if_not(_InputIterator __first, _InputIterator __last,
+		  _Predicate __pred)
+    {
+      return std::__find_if(__first, __last,
+			    __gnu_cxx::__ops::__negate(__pred),
+			    std::__iterator_category(__first));
+    }
+
+  /// Like find_if_not(), but uses and updates a count of the
+  /// remaining range length instead of comparing against an end
+  /// iterator.
+  template<typename _InputIterator, typename _Predicate, typename _Distance>
+    _GLIBCXX20_CONSTEXPR
+    _InputIterator
+    __find_if_not_n(_InputIterator __first, _Distance& __len, _Predicate __pred)
+    {
+      for (; __len; --__len,  (void) ++__first)
+	if (!__pred(__first))
+	  break;
+      return __first;
+    }
+
+  // set_difference
+  // set_intersection
+  // set_symmetric_difference
+  // set_union
+  // for_each
+  // find
+  // find_if
+  // find_first_of
+  // adjacent_find
+  // count
+  // count_if
+  // search
+
+  template<typename _ForwardIterator1, typename _ForwardIterator2,
+	   typename _BinaryPredicate>
+    _GLIBCXX20_CONSTEXPR
+    _ForwardIterator1
+    __search(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
+	     _ForwardIterator2 __first2, _ForwardIterator2 __last2,
+	     _BinaryPredicate  __predicate)
+    {
+      // Test for empty ranges
+      if (__first1 == __last1 || __first2 == __last2)
+	return __first1;
+
+      // Test for a pattern of length 1.
+      _ForwardIterator2 __p1(__first2);
+      if (++__p1 == __last2)
+	return std::__find_if(__first1, __last1,
+		__gnu_cxx::__ops::__iter_comp_iter(__predicate, __first2));
+
+      // General case.
+      _ForwardIterator1 __current = __first1;
+
+      for (;;)
+	{
+	  __first1 =
+	    std::__find_if(__first1, __last1,
+		__gnu_cxx::__ops::__iter_comp_iter(__predicate, __first2));
+
+	  if (__first1 == __last1)
+	    return __last1;
+
+	  _ForwardIterator2 __p = __p1;
+	  __current = __first1;
+	  if (++__current == __last1)
+	    return __last1;
+
+	  while (__predicate(__current, __p))
+	    {
+	      if (++__p == __last2)
+		return __first1;
+	      if (++__current == __last1)
+		return __last1;
+	    }
+	  ++__first1;
+	}
+      return __first1;
+    }
+
+  // search_n
+
+  /**
+   *  This is an helper function for search_n overloaded for forward iterators.
+  */
+  template<typename _ForwardIterator, typename _Integer,
+	   typename _UnaryPredicate>
+    _GLIBCXX20_CONSTEXPR
+    _ForwardIterator
+    __search_n_aux(_ForwardIterator __first, _ForwardIterator __last,
+		   _Integer __count, _UnaryPredicate __unary_pred,
+		   std::forward_iterator_tag)
+    {
+      __first = std::__find_if(__first, __last, __unary_pred);
+      while (__first != __last)
+	{
+	  typename iterator_traits<_ForwardIterator>::difference_type
+	    __n = __count;
+	  _ForwardIterator __i = __first;
+	  ++__i;
+	  while (__i != __last && __n != 1 && __unary_pred(__i))
+	    {
+	      ++__i;
+	      --__n;
+	    }
+	  if (__n == 1)
+	    return __first;
+	  if (__i == __last)
+	    return __last;
+	  __first = std::__find_if(++__i, __last, __unary_pred);
+	}
+      return __last;
+    }
+
+  /**
+   *  This is an helper function for search_n overloaded for random access
+   *  iterators.
+  */
+  template<typename _RandomAccessIter, typename _Integer,
+	   typename _UnaryPredicate>
+    _GLIBCXX20_CONSTEXPR
+    _RandomAccessIter
+    __search_n_aux(_RandomAccessIter __first, _RandomAccessIter __last,
+		   _Integer __count, _UnaryPredicate __unary_pred,
+		   std::random_access_iterator_tag)
+    {
+      typedef typename std::iterator_traits<_RandomAccessIter>::difference_type
+	_DistanceType;
+
+      _DistanceType __tailSize = __last - __first;
+      _DistanceType __remainder = __count;
+
+      while (__remainder <= __tailSize) // the main loop...
+	{
+	  __first += __remainder;
+	  __tailSize -= __remainder;
+	  // __first here is always pointing to one past the last element of
+	  // next possible match.
+	  _RandomAccessIter __backTrack = __first; 
+	  while (__unary_pred(--__backTrack))
+	    {
+	      if (--__remainder == 0)
+		return (__first - __count); // Success
+	    }
+	  __remainder = __count + 1 - (__first - __backTrack);
+	}
+      return __last; // Failure
+    }
+
+  template<typename _ForwardIterator, typename _Integer,
+	   typename _UnaryPredicate>
+    _GLIBCXX20_CONSTEXPR
+    _ForwardIterator
+    __search_n(_ForwardIterator __first, _ForwardIterator __last,
+	       _Integer __count,
+	       _UnaryPredicate __unary_pred)
+    {
+      if (__count <= 0)
+	return __first;
+
+      if (__count == 1)
+	return std::__find_if(__first, __last, __unary_pred);
+
+      return std::__search_n_aux(__first, __last, __count, __unary_pred,
+				 std::__iterator_category(__first));
+    }
+
+  // find_end for forward iterators.
+  template<typename _ForwardIterator1, typename _ForwardIterator2,
+	   typename _BinaryPredicate>
+    _GLIBCXX20_CONSTEXPR
+    _ForwardIterator1
+    __find_end(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
+	       _ForwardIterator2 __first2, _ForwardIterator2 __last2,
+	       forward_iterator_tag, forward_iterator_tag,
+	       _BinaryPredicate __comp)
+    {
+      if (__first2 == __last2)
+	return __last1;
+
+      _ForwardIterator1 __result = __last1;
+      while (1)
+	{
+	  _ForwardIterator1 __new_result
+	    = std::__search(__first1, __last1, __first2, __last2, __comp);
+	  if (__new_result == __last1)
+	    return __result;
+	  else
+	    {
+	      __result = __new_result;
+	      __first1 = __new_result;
+	      ++__first1;
+	    }
+	}
+    }
+
+  // find_end for bidirectional iterators (much faster).
+  template<typename _BidirectionalIterator1, typename _BidirectionalIterator2,
+	   typename _BinaryPredicate>
+    _GLIBCXX20_CONSTEXPR
+    _BidirectionalIterator1
+    __find_end(_BidirectionalIterator1 __first1,
+	       _BidirectionalIterator1 __last1,
+	       _BidirectionalIterator2 __first2,
+	       _BidirectionalIterator2 __last2,
+	       bidirectional_iterator_tag, bidirectional_iterator_tag,
+	       _BinaryPredicate __comp)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_BidirectionalIteratorConcept<
+				  _BidirectionalIterator1>)
+      __glibcxx_function_requires(_BidirectionalIteratorConcept<
+				  _BidirectionalIterator2>)
+
+      typedef reverse_iterator<_BidirectionalIterator1> _RevIterator1;
+      typedef reverse_iterator<_BidirectionalIterator2> _RevIterator2;
+
+      _RevIterator1 __rlast1(__first1);
+      _RevIterator2 __rlast2(__first2);
+      _RevIterator1 __rresult = std::__search(_RevIterator1(__last1), __rlast1,
+					      _RevIterator2(__last2), __rlast2,
+					      __comp);
+
+      if (__rresult == __rlast1)
+	return __last1;
+      else
+	{
+	  _BidirectionalIterator1 __result = __rresult.base();
+	  std::advance(__result, -std::distance(__first2, __last2));
+	  return __result;
+	}
+    }
+
+  /**
+   *  @brief  Find last matching subsequence in a sequence.
+   *  @ingroup non_mutating_algorithms
+   *  @param  __first1  Start of range to search.
+   *  @param  __last1   End of range to search.
+   *  @param  __first2  Start of sequence to match.
+   *  @param  __last2   End of sequence to match.
+   *  @return   The last iterator @c i in the range
+   *  @p [__first1,__last1-(__last2-__first2)) such that @c *(i+N) ==
+   *  @p *(__first2+N) for each @c N in the range @p
+   *  [0,__last2-__first2), or @p __last1 if no such iterator exists.
+   *
+   *  Searches the range @p [__first1,__last1) for a sub-sequence that
+   *  compares equal value-by-value with the sequence given by @p
+   *  [__first2,__last2) and returns an iterator to the __first
+   *  element of the sub-sequence, or @p __last1 if the sub-sequence
+   *  is not found.  The sub-sequence will be the last such
+   *  subsequence contained in [__first1,__last1).
+   *
+   *  Because the sub-sequence must lie completely within the range @p
+   *  [__first1,__last1) it must start at a position less than @p
+   *  __last1-(__last2-__first2) where @p __last2-__first2 is the
+   *  length of the sub-sequence.  This means that the returned
+   *  iterator @c i will be in the range @p
+   *  [__first1,__last1-(__last2-__first2))
+  */
+  template<typename _ForwardIterator1, typename _ForwardIterator2>
+    _GLIBCXX20_CONSTEXPR
+    inline _ForwardIterator1
+    find_end(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
+	     _ForwardIterator2 __first2, _ForwardIterator2 __last2)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator1>)
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator2>)
+      __glibcxx_function_requires(_EqualOpConcept<
+	    typename iterator_traits<_ForwardIterator1>::value_type,
+	    typename iterator_traits<_ForwardIterator2>::value_type>)
+      __glibcxx_requires_valid_range(__first1, __last1);
+      __glibcxx_requires_valid_range(__first2, __last2);
+
+      return std::__find_end(__first1, __last1, __first2, __last2,
+			     std::__iterator_category(__first1),
+			     std::__iterator_category(__first2),
+			     __gnu_cxx::__ops::__iter_equal_to_iter());
+    }
+
+  /**
+   *  @brief  Find last matching subsequence in a sequence using a predicate.
+   *  @ingroup non_mutating_algorithms
+   *  @param  __first1  Start of range to search.
+   *  @param  __last1   End of range to search.
+   *  @param  __first2  Start of sequence to match.
+   *  @param  __last2   End of sequence to match.
+   *  @param  __comp    The predicate to use.
+   *  @return The last iterator @c i in the range @p
+   *  [__first1,__last1-(__last2-__first2)) such that @c
+   *  predicate(*(i+N), @p (__first2+N)) is true for each @c N in the
+   *  range @p [0,__last2-__first2), or @p __last1 if no such iterator
+   *  exists.
+   *
+   *  Searches the range @p [__first1,__last1) for a sub-sequence that
+   *  compares equal value-by-value with the sequence given by @p
+   *  [__first2,__last2) using comp as a predicate and returns an
+   *  iterator to the first element of the sub-sequence, or @p __last1
+   *  if the sub-sequence is not found.  The sub-sequence will be the
+   *  last such subsequence contained in [__first,__last1).
+   *
+   *  Because the sub-sequence must lie completely within the range @p
+   *  [__first1,__last1) it must start at a position less than @p
+   *  __last1-(__last2-__first2) where @p __last2-__first2 is the
+   *  length of the sub-sequence.  This means that the returned
+   *  iterator @c i will be in the range @p
+   *  [__first1,__last1-(__last2-__first2))
+  */
+  template<typename _ForwardIterator1, typename _ForwardIterator2,
+	   typename _BinaryPredicate>
+    _GLIBCXX20_CONSTEXPR
+    inline _ForwardIterator1
+    find_end(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
+	     _ForwardIterator2 __first2, _ForwardIterator2 __last2,
+	     _BinaryPredicate __comp)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator1>)
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator2>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,
+	    typename iterator_traits<_ForwardIterator1>::value_type,
+	    typename iterator_traits<_ForwardIterator2>::value_type>)
+      __glibcxx_requires_valid_range(__first1, __last1);
+      __glibcxx_requires_valid_range(__first2, __last2);
+
+      return std::__find_end(__first1, __last1, __first2, __last2,
+			     std::__iterator_category(__first1),
+			     std::__iterator_category(__first2),
+			     __gnu_cxx::__ops::__iter_comp_iter(__comp));
+    }
+
+#if __cplusplus >= 201103L
+  /**
+   *  @brief  Checks that a predicate is true for all the elements
+   *          of a sequence.
+   *  @ingroup non_mutating_algorithms
+   *  @param  __first   An input iterator.
+   *  @param  __last    An input iterator.
+   *  @param  __pred    A predicate.
+   *  @return  True if the check is true, false otherwise.
+   *
+   *  Returns true if @p __pred is true for each element in the range
+   *  @p [__first,__last), and false otherwise.
+  */
+  template<typename _InputIterator, typename _Predicate>
+    _GLIBCXX20_CONSTEXPR
+    inline bool
+    all_of(_InputIterator __first, _InputIterator __last, _Predicate __pred)
+    { return __last == std::find_if_not(__first, __last, __pred); }
+
+  /**
+   *  @brief  Checks that a predicate is false for all the elements
+   *          of a sequence.
+   *  @ingroup non_mutating_algorithms
+   *  @param  __first   An input iterator.
+   *  @param  __last    An input iterator.
+   *  @param  __pred    A predicate.
+   *  @return  True if the check is true, false otherwise.
+   *
+   *  Returns true if @p __pred is false for each element in the range
+   *  @p [__first,__last), and false otherwise.
+  */
+  template<typename _InputIterator, typename _Predicate>
+    _GLIBCXX20_CONSTEXPR
+    inline bool
+    none_of(_InputIterator __first, _InputIterator __last, _Predicate __pred)
+    { return __last == _GLIBCXX_STD_A::find_if(__first, __last, __pred); }
+
+  /**
+   *  @brief  Checks that a predicate is true for at least one element
+   *          of a sequence.
+   *  @ingroup non_mutating_algorithms
+   *  @param  __first   An input iterator.
+   *  @param  __last    An input iterator.
+   *  @param  __pred    A predicate.
+   *  @return  True if the check is true, false otherwise.
+   *
+   *  Returns true if an element exists in the range @p
+   *  [__first,__last) such that @p __pred is true, and false
+   *  otherwise.
+  */
+  template<typename _InputIterator, typename _Predicate>
+    _GLIBCXX20_CONSTEXPR
+    inline bool
+    any_of(_InputIterator __first, _InputIterator __last, _Predicate __pred)
+    { return !std::none_of(__first, __last, __pred); }
+
+  /**
+   *  @brief  Find the first element in a sequence for which a
+   *          predicate is false.
+   *  @ingroup non_mutating_algorithms
+   *  @param  __first  An input iterator.
+   *  @param  __last   An input iterator.
+   *  @param  __pred   A predicate.
+   *  @return   The first iterator @c i in the range @p [__first,__last)
+   *  such that @p __pred(*i) is false, or @p __last if no such iterator exists.
+  */
+  template<typename _InputIterator, typename _Predicate>
+    _GLIBCXX20_CONSTEXPR
+    inline _InputIterator
+    find_if_not(_InputIterator __first, _InputIterator __last,
+		_Predicate __pred)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
+      __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,
+	      typename iterator_traits<_InputIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+      return std::__find_if_not(__first, __last,
+				__gnu_cxx::__ops::__pred_iter(__pred));
+    }
+
+  /**
+   *  @brief  Checks whether the sequence is partitioned.
+   *  @ingroup mutating_algorithms
+   *  @param  __first  An input iterator.
+   *  @param  __last   An input iterator.
+   *  @param  __pred   A predicate.
+   *  @return  True if the range @p [__first,__last) is partioned by @p __pred,
+   *  i.e. if all elements that satisfy @p __pred appear before those that
+   *  do not.
+  */
+  template<typename _InputIterator, typename _Predicate>
+    _GLIBCXX20_CONSTEXPR
+    inline bool
+    is_partitioned(_InputIterator __first, _InputIterator __last,
+		   _Predicate __pred)
+    {
+      __first = std::find_if_not(__first, __last, __pred);
+      if (__first == __last)
+	return true;
+      ++__first;
+      return std::none_of(__first, __last, __pred);
+    }
+
+  /**
+   *  @brief  Find the partition point of a partitioned range.
+   *  @ingroup mutating_algorithms
+   *  @param  __first   An iterator.
+   *  @param  __last    Another iterator.
+   *  @param  __pred    A predicate.
+   *  @return  An iterator @p mid such that @p all_of(__first, mid, __pred)
+   *           and @p none_of(mid, __last, __pred) are both true.
+  */
+  template<typename _ForwardIterator, typename _Predicate>
+    _GLIBCXX20_CONSTEXPR
+    _ForwardIterator
+    partition_point(_ForwardIterator __first, _ForwardIterator __last,
+		    _Predicate __pred)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+      __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,
+	      typename iterator_traits<_ForwardIterator>::value_type>)
+
+      // A specific debug-mode test will be necessary...
+      __glibcxx_requires_valid_range(__first, __last);
+
+      typedef typename iterator_traits<_ForwardIterator>::difference_type
+	_DistanceType;
+
+      _DistanceType __len = std::distance(__first, __last);
+
+      while (__len > 0)
+	{
+	  _DistanceType __half = __len >> 1;
+	  _ForwardIterator __middle = __first;
+	  std::advance(__middle, __half);
+	  if (__pred(*__middle))
+	    {
+	      __first = __middle;
+	      ++__first;
+	      __len = __len - __half - 1;
+	    }
+	  else
+	    __len = __half;
+	}
+      return __first;
+    }
+#endif
+
+  template<typename _InputIterator, typename _OutputIterator,
+	   typename _Predicate>
+    _GLIBCXX20_CONSTEXPR
+    _OutputIterator
+    __remove_copy_if(_InputIterator __first, _InputIterator __last,
+		     _OutputIterator __result, _Predicate __pred)
+    {
+      for (; __first != __last; ++__first)
+	if (!__pred(__first))
+	  {
+	    *__result = *__first;
+	    ++__result;
+	  }
+      return __result;
+    }
+
+  /**
+   *  @brief Copy a sequence, removing elements of a given value.
+   *  @ingroup mutating_algorithms
+   *  @param  __first   An input iterator.
+   *  @param  __last    An input iterator.
+   *  @param  __result  An output iterator.
+   *  @param  __value   The value to be removed.
+   *  @return   An iterator designating the end of the resulting sequence.
+   *
+   *  Copies each element in the range @p [__first,__last) not equal
+   *  to @p __value to the range beginning at @p __result.
+   *  remove_copy() is stable, so the relative order of elements that
+   *  are copied is unchanged.
+  */
+  template<typename _InputIterator, typename _OutputIterator, typename _Tp>
+    _GLIBCXX20_CONSTEXPR
+    inline _OutputIterator
+    remove_copy(_InputIterator __first, _InputIterator __last,
+		_OutputIterator __result, const _Tp& __value)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
+	    typename iterator_traits<_InputIterator>::value_type>)
+      __glibcxx_function_requires(_EqualOpConcept<
+	    typename iterator_traits<_InputIterator>::value_type, _Tp>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      return std::__remove_copy_if(__first, __last, __result,
+	__gnu_cxx::__ops::__iter_equals_val(__value));
+    }
+
+  /**
+   *  @brief Copy a sequence, removing elements for which a predicate is true.
+   *  @ingroup mutating_algorithms
+   *  @param  __first   An input iterator.
+   *  @param  __last    An input iterator.
+   *  @param  __result  An output iterator.
+   *  @param  __pred    A predicate.
+   *  @return   An iterator designating the end of the resulting sequence.
+   *
+   *  Copies each element in the range @p [__first,__last) for which
+   *  @p __pred returns false to the range beginning at @p __result.
+   *
+   *  remove_copy_if() is stable, so the relative order of elements that are
+   *  copied is unchanged.
+  */
+  template<typename _InputIterator, typename _OutputIterator,
+	   typename _Predicate>
+    _GLIBCXX20_CONSTEXPR
+    inline _OutputIterator
+    remove_copy_if(_InputIterator __first, _InputIterator __last,
+		   _OutputIterator __result, _Predicate __pred)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
+	    typename iterator_traits<_InputIterator>::value_type>)
+      __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,
+	    typename iterator_traits<_InputIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      return std::__remove_copy_if(__first, __last, __result,
+				   __gnu_cxx::__ops::__pred_iter(__pred));
+    }
+
+#if __cplusplus >= 201103L
+  /**
+   *  @brief Copy the elements of a sequence for which a predicate is true.
+   *  @ingroup mutating_algorithms
+   *  @param  __first   An input iterator.
+   *  @param  __last    An input iterator.
+   *  @param  __result  An output iterator.
+   *  @param  __pred    A predicate.
+   *  @return   An iterator designating the end of the resulting sequence.
+   *
+   *  Copies each element in the range @p [__first,__last) for which
+   *  @p __pred returns true to the range beginning at @p __result.
+   *
+   *  copy_if() is stable, so the relative order of elements that are
+   *  copied is unchanged.
+  */
+  template<typename _InputIterator, typename _OutputIterator,
+	   typename _Predicate>
+    _GLIBCXX20_CONSTEXPR
+    _OutputIterator
+    copy_if(_InputIterator __first, _InputIterator __last,
+	    _OutputIterator __result, _Predicate __pred)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
+	    typename iterator_traits<_InputIterator>::value_type>)
+      __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,
+	    typename iterator_traits<_InputIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      for (; __first != __last; ++__first)
+	if (__pred(*__first))
+	  {
+	    *__result = *__first;
+	    ++__result;
+	  }
+      return __result;
+    }
+
+  template<typename _InputIterator, typename _Size, typename _OutputIterator>
+    _GLIBCXX20_CONSTEXPR
+    _OutputIterator
+    __copy_n(_InputIterator __first, _Size __n,
+	     _OutputIterator __result, input_iterator_tag)
+    {
+      return std::__niter_wrap(__result,
+			       __copy_n_a(__first, __n,
+					  std::__niter_base(__result), true));
+    }
+
+  template<typename _RandomAccessIterator, typename _Size,
+	   typename _OutputIterator>
+    _GLIBCXX20_CONSTEXPR
+    inline _OutputIterator
+    __copy_n(_RandomAccessIterator __first, _Size __n,
+	     _OutputIterator __result, random_access_iterator_tag)
+    { return std::copy(__first, __first + __n, __result); }
+
+  /**
+   *  @brief Copies the range [first,first+n) into [result,result+n).
+   *  @ingroup mutating_algorithms
+   *  @param  __first  An input iterator.
+   *  @param  __n      The number of elements to copy.
+   *  @param  __result An output iterator.
+   *  @return  result+n.
+   *
+   *  This inline function will boil down to a call to @c memmove whenever
+   *  possible.  Failing that, if random access iterators are passed, then the
+   *  loop count will be known (and therefore a candidate for compiler
+   *  optimizations such as unrolling).
+  */
+  template<typename _InputIterator, typename _Size, typename _OutputIterator>
+    _GLIBCXX20_CONSTEXPR
+    inline _OutputIterator
+    copy_n(_InputIterator __first, _Size __n, _OutputIterator __result)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
+	    typename iterator_traits<_InputIterator>::value_type>)
+
+      const auto __n2 = std::__size_to_integer(__n);
+      if (__n2 <= 0)
+	return __result;
+
+      __glibcxx_requires_can_increment(__first, __n2);
+      __glibcxx_requires_can_increment(__result, __n2);
+
+      return std::__copy_n(__first, __n2, __result,
+			   std::__iterator_category(__first));
+    }
+
+  /**
+   *  @brief Copy the elements of a sequence to separate output sequences
+   *         depending on the truth value of a predicate.
+   *  @ingroup mutating_algorithms
+   *  @param  __first   An input iterator.
+   *  @param  __last    An input iterator.
+   *  @param  __out_true   An output iterator.
+   *  @param  __out_false  An output iterator.
+   *  @param  __pred    A predicate.
+   *  @return   A pair designating the ends of the resulting sequences.
+   *
+   *  Copies each element in the range @p [__first,__last) for which
+   *  @p __pred returns true to the range beginning at @p out_true
+   *  and each element for which @p __pred returns false to @p __out_false.
+  */
+  template<typename _InputIterator, typename _OutputIterator1,
+	   typename _OutputIterator2, typename _Predicate>
+    _GLIBCXX20_CONSTEXPR
+    pair<_OutputIterator1, _OutputIterator2>
+    partition_copy(_InputIterator __first, _InputIterator __last,
+		   _OutputIterator1 __out_true, _OutputIterator2 __out_false,
+		   _Predicate __pred)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator1,
+	    typename iterator_traits<_InputIterator>::value_type>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator2,
+	    typename iterator_traits<_InputIterator>::value_type>)
+      __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,
+	    typename iterator_traits<_InputIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+      
+      for (; __first != __last; ++__first)
+	if (__pred(*__first))
+	  {
+	    *__out_true = *__first;
+	    ++__out_true;
+	  }
+	else
+	  {
+	    *__out_false = *__first;
+	    ++__out_false;
+	  }
+
+      return pair<_OutputIterator1, _OutputIterator2>(__out_true, __out_false);
+    }
+#endif // C++11
+
+  /**
+   *  @brief Remove elements from a sequence.
+   *  @ingroup mutating_algorithms
+   *  @param  __first  An input iterator.
+   *  @param  __last   An input iterator.
+   *  @param  __value  The value to be removed.
+   *  @return   An iterator designating the end of the resulting sequence.
+   *
+   *  All elements equal to @p __value are removed from the range
+   *  @p [__first,__last).
+   *
+   *  remove() is stable, so the relative order of elements that are
+   *  not removed is unchanged.
+   *
+   *  Elements between the end of the resulting sequence and @p __last
+   *  are still present, but their value is unspecified.
+  */
+  template<typename _ForwardIterator, typename _Tp>
+    _GLIBCXX20_CONSTEXPR
+    inline _ForwardIterator
+    remove(_ForwardIterator __first, _ForwardIterator __last,
+	   const _Tp& __value)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
+				  _ForwardIterator>)
+      __glibcxx_function_requires(_EqualOpConcept<
+	    typename iterator_traits<_ForwardIterator>::value_type, _Tp>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      return std::__remove_if(__first, __last,
+		__gnu_cxx::__ops::__iter_equals_val(__value));
+    }
+
+  /**
+   *  @brief Remove elements from a sequence using a predicate.
+   *  @ingroup mutating_algorithms
+   *  @param  __first  A forward iterator.
+   *  @param  __last   A forward iterator.
+   *  @param  __pred   A predicate.
+   *  @return   An iterator designating the end of the resulting sequence.
+   *
+   *  All elements for which @p __pred returns true are removed from the range
+   *  @p [__first,__last).
+   *
+   *  remove_if() is stable, so the relative order of elements that are
+   *  not removed is unchanged.
+   *
+   *  Elements between the end of the resulting sequence and @p __last
+   *  are still present, but their value is unspecified.
+  */
+  template<typename _ForwardIterator, typename _Predicate>
+    _GLIBCXX20_CONSTEXPR
+    inline _ForwardIterator
+    remove_if(_ForwardIterator __first, _ForwardIterator __last,
+	      _Predicate __pred)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
+				  _ForwardIterator>)
+      __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,
+	    typename iterator_traits<_ForwardIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      return std::__remove_if(__first, __last,
+			      __gnu_cxx::__ops::__pred_iter(__pred));
+    }
+
+  template<typename _ForwardIterator, typename _BinaryPredicate>
+    _GLIBCXX20_CONSTEXPR
+    _ForwardIterator
+    __adjacent_find(_ForwardIterator __first, _ForwardIterator __last,
+		    _BinaryPredicate __binary_pred)
+    {
+      if (__first == __last)
+	return __last;
+      _ForwardIterator __next = __first;
+      while (++__next != __last)
+	{
+	  if (__binary_pred(__first, __next))
+	    return __first;
+	  __first = __next;
+	}
+      return __last;
+    }
+
+  template<typename _ForwardIterator, typename _BinaryPredicate>
+    _GLIBCXX20_CONSTEXPR
+    _ForwardIterator
+    __unique(_ForwardIterator __first, _ForwardIterator __last,
+	     _BinaryPredicate __binary_pred)
+    {
+      // Skip the beginning, if already unique.
+      __first = std::__adjacent_find(__first, __last, __binary_pred);
+      if (__first == __last)
+	return __last;
+
+      // Do the real copy work.
+      _ForwardIterator __dest = __first;
+      ++__first;
+      while (++__first != __last)
+	if (!__binary_pred(__dest, __first))
+	  *++__dest = _GLIBCXX_MOVE(*__first);
+      return ++__dest;
+    }
+
+  /**
+   *  @brief Remove consecutive duplicate values from a sequence.
+   *  @ingroup mutating_algorithms
+   *  @param  __first  A forward iterator.
+   *  @param  __last   A forward iterator.
+   *  @return  An iterator designating the end of the resulting sequence.
+   *
+   *  Removes all but the first element from each group of consecutive
+   *  values that compare equal.
+   *  unique() is stable, so the relative order of elements that are
+   *  not removed is unchanged.
+   *  Elements between the end of the resulting sequence and @p __last
+   *  are still present, but their value is unspecified.
+  */
+  template<typename _ForwardIterator>
+    _GLIBCXX20_CONSTEXPR
+    inline _ForwardIterator
+    unique(_ForwardIterator __first, _ForwardIterator __last)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
+				  _ForwardIterator>)
+      __glibcxx_function_requires(_EqualityComparableConcept<
+		     typename iterator_traits<_ForwardIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      return std::__unique(__first, __last,
+			   __gnu_cxx::__ops::__iter_equal_to_iter());
+    }
+
+  /**
+   *  @brief Remove consecutive values from a sequence using a predicate.
+   *  @ingroup mutating_algorithms
+   *  @param  __first        A forward iterator.
+   *  @param  __last         A forward iterator.
+   *  @param  __binary_pred  A binary predicate.
+   *  @return  An iterator designating the end of the resulting sequence.
+   *
+   *  Removes all but the first element from each group of consecutive
+   *  values for which @p __binary_pred returns true.
+   *  unique() is stable, so the relative order of elements that are
+   *  not removed is unchanged.
+   *  Elements between the end of the resulting sequence and @p __last
+   *  are still present, but their value is unspecified.
+  */
+  template<typename _ForwardIterator, typename _BinaryPredicate>
+    _GLIBCXX20_CONSTEXPR
+    inline _ForwardIterator
+    unique(_ForwardIterator __first, _ForwardIterator __last,
+	   _BinaryPredicate __binary_pred)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
+				  _ForwardIterator>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,
+		typename iterator_traits<_ForwardIterator>::value_type,
+		typename iterator_traits<_ForwardIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      return std::__unique(__first, __last,
+			   __gnu_cxx::__ops::__iter_comp_iter(__binary_pred));
+    }
+
+  /**
+   *  This is an uglified
+   *  unique_copy(_InputIterator, _InputIterator, _OutputIterator,
+   *              _BinaryPredicate)
+   *  overloaded for forward iterators and output iterator as result.
+  */
+  template<typename _ForwardIterator, typename _OutputIterator,
+	   typename _BinaryPredicate>
+    _GLIBCXX20_CONSTEXPR
+    _OutputIterator
+    __unique_copy(_ForwardIterator __first, _ForwardIterator __last,
+		  _OutputIterator __result, _BinaryPredicate __binary_pred,
+		  forward_iterator_tag, output_iterator_tag)
+    {
+      // concept requirements -- iterators already checked
+      __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,
+	  typename iterator_traits<_ForwardIterator>::value_type,
+	  typename iterator_traits<_ForwardIterator>::value_type>)
+
+      _ForwardIterator __next = __first;
+      *__result = *__first;
+      while (++__next != __last)
+	if (!__binary_pred(__first, __next))
+	  {
+	    __first = __next;
+	    *++__result = *__first;
+	  }
+      return ++__result;
+    }
+
+  /**
+   *  This is an uglified
+   *  unique_copy(_InputIterator, _InputIterator, _OutputIterator,
+   *              _BinaryPredicate)
+   *  overloaded for input iterators and output iterator as result.
+  */
+  template<typename _InputIterator, typename _OutputIterator,
+	   typename _BinaryPredicate>
+    _GLIBCXX20_CONSTEXPR
+    _OutputIterator
+    __unique_copy(_InputIterator __first, _InputIterator __last,
+		  _OutputIterator __result, _BinaryPredicate __binary_pred,
+		  input_iterator_tag, output_iterator_tag)
+    {
+      // concept requirements -- iterators already checked
+      __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,
+	  typename iterator_traits<_InputIterator>::value_type,
+	  typename iterator_traits<_InputIterator>::value_type>)
+
+      typename iterator_traits<_InputIterator>::value_type __value = *__first;
+      __decltype(__gnu_cxx::__ops::__iter_comp_val(__binary_pred))
+	__rebound_pred
+	= __gnu_cxx::__ops::__iter_comp_val(__binary_pred);
+      *__result = __value;
+      while (++__first != __last)
+	if (!__rebound_pred(__first, __value))
+	  {
+	    __value = *__first;
+	    *++__result = __value;
+	  }
+      return ++__result;
+    }
+
+  /**
+   *  This is an uglified
+   *  unique_copy(_InputIterator, _InputIterator, _OutputIterator,
+   *              _BinaryPredicate)
+   *  overloaded for input iterators and forward iterator as result.
+  */
+  template<typename _InputIterator, typename _ForwardIterator,
+	   typename _BinaryPredicate>
+    _GLIBCXX20_CONSTEXPR
+    _ForwardIterator
+    __unique_copy(_InputIterator __first, _InputIterator __last,
+		  _ForwardIterator __result, _BinaryPredicate __binary_pred,
+		  input_iterator_tag, forward_iterator_tag)
+    {
+      // concept requirements -- iterators already checked
+      __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,
+	  typename iterator_traits<_ForwardIterator>::value_type,
+	  typename iterator_traits<_InputIterator>::value_type>)
+      *__result = *__first;
+      while (++__first != __last)
+	if (!__binary_pred(__result, __first))
+	  *++__result = *__first;
+      return ++__result;
+    }
+
+  /**
+   *  This is an uglified reverse(_BidirectionalIterator,
+   *                              _BidirectionalIterator)
+   *  overloaded for bidirectional iterators.
+  */
+  template<typename _BidirectionalIterator>
+    _GLIBCXX20_CONSTEXPR
+    void
+    __reverse(_BidirectionalIterator __first, _BidirectionalIterator __last,
+	      bidirectional_iterator_tag)
+    {
+      while (true)
+	if (__first == __last || __first == --__last)
+	  return;
+	else
+	  {
+	    std::iter_swap(__first, __last);
+	    ++__first;
+	  }
+    }
+
+  /**
+   *  This is an uglified reverse(_BidirectionalIterator,
+   *                              _BidirectionalIterator)
+   *  overloaded for random access iterators.
+  */
+  template<typename _RandomAccessIterator>
+    _GLIBCXX20_CONSTEXPR
+    void
+    __reverse(_RandomAccessIterator __first, _RandomAccessIterator __last,
+	      random_access_iterator_tag)
+    {
+      if (__first == __last)
+	return;
+      --__last;
+      while (__first < __last)
+	{
+	  std::iter_swap(__first, __last);
+	  ++__first;
+	  --__last;
+	}
+    }
+
+  /**
+   *  @brief Reverse a sequence.
+   *  @ingroup mutating_algorithms
+   *  @param  __first  A bidirectional iterator.
+   *  @param  __last   A bidirectional iterator.
+   *  @return   reverse() returns no value.
+   *
+   *  Reverses the order of the elements in the range @p [__first,__last),
+   *  so that the first element becomes the last etc.
+   *  For every @c i such that @p 0<=i<=(__last-__first)/2), @p reverse()
+   *  swaps @p *(__first+i) and @p *(__last-(i+1))
+  */
+  template<typename _BidirectionalIterator>
+    _GLIBCXX20_CONSTEXPR
+    inline void
+    reverse(_BidirectionalIterator __first, _BidirectionalIterator __last)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_Mutable_BidirectionalIteratorConcept<
+				  _BidirectionalIterator>)
+      __glibcxx_requires_valid_range(__first, __last);
+      std::__reverse(__first, __last, std::__iterator_category(__first));
+    }
+
+  /**
+   *  @brief Copy a sequence, reversing its elements.
+   *  @ingroup mutating_algorithms
+   *  @param  __first   A bidirectional iterator.
+   *  @param  __last    A bidirectional iterator.
+   *  @param  __result  An output iterator.
+   *  @return  An iterator designating the end of the resulting sequence.
+   *
+   *  Copies the elements in the range @p [__first,__last) to the
+   *  range @p [__result,__result+(__last-__first)) such that the
+   *  order of the elements is reversed.  For every @c i such that @p
+   *  0<=i<=(__last-__first), @p reverse_copy() performs the
+   *  assignment @p *(__result+(__last-__first)-1-i) = *(__first+i).
+   *  The ranges @p [__first,__last) and @p
+   *  [__result,__result+(__last-__first)) must not overlap.
+  */
+  template<typename _BidirectionalIterator, typename _OutputIterator>
+    _GLIBCXX20_CONSTEXPR
+    _OutputIterator
+    reverse_copy(_BidirectionalIterator __first, _BidirectionalIterator __last,
+		 _OutputIterator __result)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_BidirectionalIteratorConcept<
+				  _BidirectionalIterator>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
+		typename iterator_traits<_BidirectionalIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      while (__first != __last)
+	{
+	  --__last;
+	  *__result = *__last;
+	  ++__result;
+	}
+      return __result;
+    }
+
+  /**
+   *  This is a helper function for the rotate algorithm specialized on RAIs.
+   *  It returns the greatest common divisor of two integer values.
+  */
+  template<typename _EuclideanRingElement>
+    _GLIBCXX20_CONSTEXPR
+    _EuclideanRingElement
+    __gcd(_EuclideanRingElement __m, _EuclideanRingElement __n)
+    {
+      while (__n != 0)
+	{
+	  _EuclideanRingElement __t = __m % __n;
+	  __m = __n;
+	  __n = __t;
+	}
+      return __m;
+    }
+
+  inline namespace _V2
+  {
+
+  /// This is a helper function for the rotate algorithm.
+  template<typename _ForwardIterator>
+    _GLIBCXX20_CONSTEXPR
+    _ForwardIterator
+    __rotate(_ForwardIterator __first,
+	     _ForwardIterator __middle,
+	     _ForwardIterator __last,
+	     forward_iterator_tag)
+    {
+      if (__first == __middle)
+	return __last;
+      else if (__last == __middle)
+	return __first;
+
+      _ForwardIterator __first2 = __middle;
+      do
+	{
+	  std::iter_swap(__first, __first2);
+	  ++__first;
+	  ++__first2;
+	  if (__first == __middle)
+	    __middle = __first2;
+	}
+      while (__first2 != __last);
+
+      _ForwardIterator __ret = __first;
+
+      __first2 = __middle;
+
+      while (__first2 != __last)
+	{
+	  std::iter_swap(__first, __first2);
+	  ++__first;
+	  ++__first2;
+	  if (__first == __middle)
+	    __middle = __first2;
+	  else if (__first2 == __last)
+	    __first2 = __middle;
+	}
+      return __ret;
+    }
+
+   /// This is a helper function for the rotate algorithm.
+  template<typename _BidirectionalIterator>
+    _GLIBCXX20_CONSTEXPR
+    _BidirectionalIterator
+    __rotate(_BidirectionalIterator __first,
+	     _BidirectionalIterator __middle,
+	     _BidirectionalIterator __last,
+	      bidirectional_iterator_tag)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_Mutable_BidirectionalIteratorConcept<
+				  _BidirectionalIterator>)
+
+      if (__first == __middle)
+	return __last;
+      else if (__last == __middle)
+	return __first;
+
+      std::__reverse(__first,  __middle, bidirectional_iterator_tag());
+      std::__reverse(__middle, __last,   bidirectional_iterator_tag());
+
+      while (__first != __middle && __middle != __last)
+	{
+	  std::iter_swap(__first, --__last);
+	  ++__first;
+	}
+
+      if (__first == __middle)
+	{
+	  std::__reverse(__middle, __last,   bidirectional_iterator_tag());
+	  return __last;
+	}
+      else
+	{
+	  std::__reverse(__first,  __middle, bidirectional_iterator_tag());
+	  return __first;
+	}
+    }
+
+  /// This is a helper function for the rotate algorithm.
+  template<typename _RandomAccessIterator>
+    _GLIBCXX20_CONSTEXPR
+    _RandomAccessIterator
+    __rotate(_RandomAccessIterator __first,
+	     _RandomAccessIterator __middle,
+	     _RandomAccessIterator __last,
+	     random_access_iterator_tag)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
+				  _RandomAccessIterator>)
+
+      if (__first == __middle)
+	return __last;
+      else if (__last == __middle)
+	return __first;
+
+      typedef typename iterator_traits<_RandomAccessIterator>::difference_type
+	_Distance;
+      typedef typename iterator_traits<_RandomAccessIterator>::value_type
+	_ValueType;
+
+      _Distance __n = __last   - __first;
+      _Distance __k = __middle - __first;
+
+      if (__k == __n - __k)
+	{
+	  std::swap_ranges(__first, __middle, __middle);
+	  return __middle;
+	}
+
+      _RandomAccessIterator __p = __first;
+      _RandomAccessIterator __ret = __first + (__last - __middle);
+
+      for (;;)
+	{
+	  if (__k < __n - __k)
+	    {
+	      if (__is_pod(_ValueType) && __k == 1)
+		{
+		  _ValueType __t = _GLIBCXX_MOVE(*__p);
+		  _GLIBCXX_MOVE3(__p + 1, __p + __n, __p);
+		  *(__p + __n - 1) = _GLIBCXX_MOVE(__t);
+		  return __ret;
+		}
+	      _RandomAccessIterator __q = __p + __k;
+	      for (_Distance __i = 0; __i < __n - __k; ++ __i)
+		{
+		  std::iter_swap(__p, __q);
+		  ++__p;
+		  ++__q;
+		}
+	      __n %= __k;
+	      if (__n == 0)
+		return __ret;
+	      std::swap(__n, __k);
+	      __k = __n - __k;
+	    }
+	  else
+	    {
+	      __k = __n - __k;
+	      if (__is_pod(_ValueType) && __k == 1)
+		{
+		  _ValueType __t = _GLIBCXX_MOVE(*(__p + __n - 1));
+		  _GLIBCXX_MOVE_BACKWARD3(__p, __p + __n - 1, __p + __n);
+		  *__p = _GLIBCXX_MOVE(__t);
+		  return __ret;
+		}
+	      _RandomAccessIterator __q = __p + __n;
+	      __p = __q - __k;
+	      for (_Distance __i = 0; __i < __n - __k; ++ __i)
+		{
+		  --__p;
+		  --__q;
+		  std::iter_swap(__p, __q);
+		}
+	      __n %= __k;
+	      if (__n == 0)
+		return __ret;
+	      std::swap(__n, __k);
+	    }
+	}
+    }
+
+   // _GLIBCXX_RESOLVE_LIB_DEFECTS
+   // DR 488. rotate throws away useful information
+  /**
+   *  @brief Rotate the elements of a sequence.
+   *  @ingroup mutating_algorithms
+   *  @param  __first   A forward iterator.
+   *  @param  __middle  A forward iterator.
+   *  @param  __last    A forward iterator.
+   *  @return  first + (last - middle).
+   *
+   *  Rotates the elements of the range @p [__first,__last) by 
+   *  @p (__middle - __first) positions so that the element at @p __middle
+   *  is moved to @p __first, the element at @p __middle+1 is moved to
+   *  @p __first+1 and so on for each element in the range
+   *  @p [__first,__last).
+   *
+   *  This effectively swaps the ranges @p [__first,__middle) and
+   *  @p [__middle,__last).
+   *
+   *  Performs
+   *   @p *(__first+(n+(__last-__middle))%(__last-__first))=*(__first+n)
+   *  for each @p n in the range @p [0,__last-__first).
+  */
+  template<typename _ForwardIterator>
+    _GLIBCXX20_CONSTEXPR
+    inline _ForwardIterator
+    rotate(_ForwardIterator __first, _ForwardIterator __middle,
+	   _ForwardIterator __last)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
+				  _ForwardIterator>)
+      __glibcxx_requires_valid_range(__first, __middle);
+      __glibcxx_requires_valid_range(__middle, __last);
+
+      return std::__rotate(__first, __middle, __last,
+			   std::__iterator_category(__first));
+    }
+
+  } // namespace _V2
+
+  /**
+   *  @brief Copy a sequence, rotating its elements.
+   *  @ingroup mutating_algorithms
+   *  @param  __first   A forward iterator.
+   *  @param  __middle  A forward iterator.
+   *  @param  __last    A forward iterator.
+   *  @param  __result  An output iterator.
+   *  @return   An iterator designating the end of the resulting sequence.
+   *
+   *  Copies the elements of the range @p [__first,__last) to the
+   *  range beginning at @result, rotating the copied elements by 
+   *  @p (__middle-__first) positions so that the element at @p __middle
+   *  is moved to @p __result, the element at @p __middle+1 is moved
+   *  to @p __result+1 and so on for each element in the range @p
+   *  [__first,__last).
+   *
+   *  Performs 
+   *  @p *(__result+(n+(__last-__middle))%(__last-__first))=*(__first+n)
+   *  for each @p n in the range @p [0,__last-__first).
+  */
+  template<typename _ForwardIterator, typename _OutputIterator>
+    _GLIBCXX20_CONSTEXPR
+    inline _OutputIterator
+    rotate_copy(_ForwardIterator __first, _ForwardIterator __middle,
+		_ForwardIterator __last, _OutputIterator __result)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
+		typename iterator_traits<_ForwardIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __middle);
+      __glibcxx_requires_valid_range(__middle, __last);
+
+      return std::copy(__first, __middle,
+		       std::copy(__middle, __last, __result));
+    }
+
+  /// This is a helper function...
+  template<typename _ForwardIterator, typename _Predicate>
+    _GLIBCXX20_CONSTEXPR
+    _ForwardIterator
+    __partition(_ForwardIterator __first, _ForwardIterator __last,
+		_Predicate __pred, forward_iterator_tag)
+    {
+      if (__first == __last)
+	return __first;
+
+      while (__pred(*__first))
+	if (++__first == __last)
+	  return __first;
+
+      _ForwardIterator __next = __first;
+
+      while (++__next != __last)
+	if (__pred(*__next))
+	  {
+	    std::iter_swap(__first, __next);
+	    ++__first;
+	  }
+
+      return __first;
+    }
+
+  /// This is a helper function...
+  template<typename _BidirectionalIterator, typename _Predicate>
+    _GLIBCXX20_CONSTEXPR
+    _BidirectionalIterator
+    __partition(_BidirectionalIterator __first, _BidirectionalIterator __last,
+		_Predicate __pred, bidirectional_iterator_tag)
+    {
+      while (true)
+	{
+	  while (true)
+	    if (__first == __last)
+	      return __first;
+	    else if (__pred(*__first))
+	      ++__first;
+	    else
+	      break;
+	  --__last;
+	  while (true)
+	    if (__first == __last)
+	      return __first;
+	    else if (!bool(__pred(*__last)))
+	      --__last;
+	    else
+	      break;
+	  std::iter_swap(__first, __last);
+	  ++__first;
+	}
+    }
+
+  // partition
+
+  /// This is a helper function...
+  /// Requires __first != __last and !__pred(__first)
+  /// and __len == distance(__first, __last).
+  ///
+  /// !__pred(__first) allows us to guarantee that we don't
+  /// move-assign an element onto itself.
+  template<typename _ForwardIterator, typename _Pointer, typename _Predicate,
+	   typename _Distance>
+    _ForwardIterator
+    __stable_partition_adaptive(_ForwardIterator __first,
+				_ForwardIterator __last,
+				_Predicate __pred, _Distance __len,
+				_Pointer __buffer,
+				_Distance __buffer_size)
+    {
+      if (__len == 1)
+	return __first;
+
+      if (__len <= __buffer_size)
+	{
+	  _ForwardIterator __result1 = __first;
+	  _Pointer __result2 = __buffer;
+
+	  // The precondition guarantees that !__pred(__first), so
+	  // move that element to the buffer before starting the loop.
+	  // This ensures that we only call __pred once per element.
+	  *__result2 = _GLIBCXX_MOVE(*__first);
+	  ++__result2;
+	  ++__first;
+	  for (; __first != __last; ++__first)
+	    if (__pred(__first))
+	      {
+		*__result1 = _GLIBCXX_MOVE(*__first);
+		++__result1;
+	      }
+	    else
+	      {
+		*__result2 = _GLIBCXX_MOVE(*__first);
+		++__result2;
+	      }
+
+	  _GLIBCXX_MOVE3(__buffer, __result2, __result1);
+	  return __result1;
+	}
+
+      _ForwardIterator __middle = __first;
+      std::advance(__middle, __len / 2);
+      _ForwardIterator __left_split =
+	std::__stable_partition_adaptive(__first, __middle, __pred,
+					 __len / 2, __buffer,
+					 __buffer_size);
+
+      // Advance past true-predicate values to satisfy this
+      // function's preconditions.
+      _Distance __right_len = __len - __len / 2;
+      _ForwardIterator __right_split =
+	std::__find_if_not_n(__middle, __right_len, __pred);
+
+      if (__right_len)
+	__right_split =
+	  std::__stable_partition_adaptive(__right_split, __last, __pred,
+					   __right_len,
+					   __buffer, __buffer_size);
+
+      return std::rotate(__left_split, __middle, __right_split);
+    }
+
+  template<typename _ForwardIterator, typename _Predicate>
+    _ForwardIterator
+    __stable_partition(_ForwardIterator __first, _ForwardIterator __last,
+		       _Predicate __pred)
+    {
+      __first = std::__find_if_not(__first, __last, __pred);
+
+      if (__first == __last)
+	return __first;
+
+      typedef typename iterator_traits<_ForwardIterator>::value_type
+	_ValueType;
+      typedef typename iterator_traits<_ForwardIterator>::difference_type
+	_DistanceType;
+
+      _Temporary_buffer<_ForwardIterator, _ValueType>
+	__buf(__first, std::distance(__first, __last));
+      return
+	std::__stable_partition_adaptive(__first, __last, __pred,
+					 _DistanceType(__buf.requested_size()),
+					 __buf.begin(),
+					 _DistanceType(__buf.size()));
+    }
+
+  /**
+   *  @brief Move elements for which a predicate is true to the beginning
+   *         of a sequence, preserving relative ordering.
+   *  @ingroup mutating_algorithms
+   *  @param  __first   A forward iterator.
+   *  @param  __last    A forward iterator.
+   *  @param  __pred    A predicate functor.
+   *  @return  An iterator @p middle such that @p __pred(i) is true for each
+   *  iterator @p i in the range @p [first,middle) and false for each @p i
+   *  in the range @p [middle,last).
+   *
+   *  Performs the same function as @p partition() with the additional
+   *  guarantee that the relative ordering of elements in each group is
+   *  preserved, so any two elements @p x and @p y in the range
+   *  @p [__first,__last) such that @p __pred(x)==__pred(y) will have the same
+   *  relative ordering after calling @p stable_partition().
+  */
+  template<typename _ForwardIterator, typename _Predicate>
+    inline _ForwardIterator
+    stable_partition(_ForwardIterator __first, _ForwardIterator __last,
+		     _Predicate __pred)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
+				  _ForwardIterator>)
+      __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,
+	    typename iterator_traits<_ForwardIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      return std::__stable_partition(__first, __last,
+				     __gnu_cxx::__ops::__pred_iter(__pred));
+    }
+
+  /// This is a helper function for the sort routines.
+  template<typename _RandomAccessIterator, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    void
+    __heap_select(_RandomAccessIterator __first,
+		  _RandomAccessIterator __middle,
+		  _RandomAccessIterator __last, _Compare __comp)
+    {
+      std::__make_heap(__first, __middle, __comp);
+      for (_RandomAccessIterator __i = __middle; __i < __last; ++__i)
+	if (__comp(__i, __first))
+	  std::__pop_heap(__first, __middle, __i, __comp);
+    }
+
+  // partial_sort
+
+  template<typename _InputIterator, typename _RandomAccessIterator,
+	   typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    _RandomAccessIterator
+    __partial_sort_copy(_InputIterator __first, _InputIterator __last,
+			_RandomAccessIterator __result_first,
+			_RandomAccessIterator __result_last,
+			_Compare __comp)
+    {
+      typedef typename iterator_traits<_InputIterator>::value_type
+	_InputValueType;
+      typedef iterator_traits<_RandomAccessIterator> _RItTraits;
+      typedef typename _RItTraits::difference_type _DistanceType;
+
+      if (__result_first == __result_last)
+	return __result_last;
+      _RandomAccessIterator __result_real_last = __result_first;
+      while (__first != __last && __result_real_last != __result_last)
+	{
+	  *__result_real_last = *__first;
+	  ++__result_real_last;
+	  ++__first;
+	}
+      
+      std::__make_heap(__result_first, __result_real_last, __comp);
+      while (__first != __last)
+	{
+	  if (__comp(__first, __result_first))
+	    std::__adjust_heap(__result_first, _DistanceType(0),
+			       _DistanceType(__result_real_last
+					     - __result_first),
+			       _InputValueType(*__first), __comp);
+	  ++__first;
+	}
+      std::__sort_heap(__result_first, __result_real_last, __comp);
+      return __result_real_last;
+    }
+
+  /**
+   *  @brief Copy the smallest elements of a sequence.
+   *  @ingroup sorting_algorithms
+   *  @param  __first   An iterator.
+   *  @param  __last    Another iterator.
+   *  @param  __result_first   A random-access iterator.
+   *  @param  __result_last    Another random-access iterator.
+   *  @return   An iterator indicating the end of the resulting sequence.
+   *
+   *  Copies and sorts the smallest N values from the range @p [__first,__last)
+   *  to the range beginning at @p __result_first, where the number of
+   *  elements to be copied, @p N, is the smaller of @p (__last-__first) and
+   *  @p (__result_last-__result_first).
+   *  After the sort if @e i and @e j are iterators in the range
+   *  @p [__result_first,__result_first+N) such that i precedes j then
+   *  *j<*i is false.
+   *  The value returned is @p __result_first+N.
+  */
+  template<typename _InputIterator, typename _RandomAccessIterator>
+    _GLIBCXX20_CONSTEXPR
+    inline _RandomAccessIterator
+    partial_sort_copy(_InputIterator __first, _InputIterator __last,
+		      _RandomAccessIterator __result_first,
+		      _RandomAccessIterator __result_last)
+    {
+#ifdef _GLIBCXX_CONCEPT_CHECKS
+      typedef typename iterator_traits<_InputIterator>::value_type
+	_InputValueType;
+      typedef typename iterator_traits<_RandomAccessIterator>::value_type
+	_OutputValueType;
+#endif
+
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
+      __glibcxx_function_requires(_ConvertibleConcept<_InputValueType,
+				  _OutputValueType>)
+      __glibcxx_function_requires(_LessThanOpConcept<_InputValueType,
+						     _OutputValueType>)
+      __glibcxx_function_requires(_LessThanComparableConcept<_OutputValueType>)
+      __glibcxx_requires_valid_range(__first, __last);
+      __glibcxx_requires_irreflexive(__first, __last);
+      __glibcxx_requires_valid_range(__result_first, __result_last);
+
+      return std::__partial_sort_copy(__first, __last,
+				      __result_first, __result_last,
+				      __gnu_cxx::__ops::__iter_less_iter());
+    }
+
+  /**
+   *  @brief Copy the smallest elements of a sequence using a predicate for
+   *         comparison.
+   *  @ingroup sorting_algorithms
+   *  @param  __first   An input iterator.
+   *  @param  __last    Another input iterator.
+   *  @param  __result_first   A random-access iterator.
+   *  @param  __result_last    Another random-access iterator.
+   *  @param  __comp    A comparison functor.
+   *  @return   An iterator indicating the end of the resulting sequence.
+   *
+   *  Copies and sorts the smallest N values from the range @p [__first,__last)
+   *  to the range beginning at @p result_first, where the number of
+   *  elements to be copied, @p N, is the smaller of @p (__last-__first) and
+   *  @p (__result_last-__result_first).
+   *  After the sort if @e i and @e j are iterators in the range
+   *  @p [__result_first,__result_first+N) such that i precedes j then
+   *  @p __comp(*j,*i) is false.
+   *  The value returned is @p __result_first+N.
+  */
+  template<typename _InputIterator, typename _RandomAccessIterator,
+	   typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    inline _RandomAccessIterator
+    partial_sort_copy(_InputIterator __first, _InputIterator __last,
+		      _RandomAccessIterator __result_first,
+		      _RandomAccessIterator __result_last,
+		      _Compare __comp)
+    {
+#ifdef _GLIBCXX_CONCEPT_CHECKS
+      typedef typename iterator_traits<_InputIterator>::value_type
+	_InputValueType;
+      typedef typename iterator_traits<_RandomAccessIterator>::value_type
+	_OutputValueType;
+#endif
+
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
+      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
+				  _RandomAccessIterator>)
+      __glibcxx_function_requires(_ConvertibleConcept<_InputValueType,
+				  _OutputValueType>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
+				  _InputValueType, _OutputValueType>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
+				  _OutputValueType, _OutputValueType>)
+      __glibcxx_requires_valid_range(__first, __last);
+      __glibcxx_requires_irreflexive_pred(__first, __last, __comp);
+      __glibcxx_requires_valid_range(__result_first, __result_last);
+
+      return std::__partial_sort_copy(__first, __last,
+				      __result_first, __result_last,
+				__gnu_cxx::__ops::__iter_comp_iter(__comp));
+    }
+
+  /// This is a helper function for the sort routine.
+  template<typename _RandomAccessIterator, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    void
+    __unguarded_linear_insert(_RandomAccessIterator __last,
+			      _Compare __comp)
+    {
+      typename iterator_traits<_RandomAccessIterator>::value_type
+	__val = _GLIBCXX_MOVE(*__last);
+      _RandomAccessIterator __next = __last;
+      --__next;
+      while (__comp(__val, __next))
+	{
+	  *__last = _GLIBCXX_MOVE(*__next);
+	  __last = __next;
+	  --__next;
+	}
+      *__last = _GLIBCXX_MOVE(__val);
+    }
+
+  /// This is a helper function for the sort routine.
+  template<typename _RandomAccessIterator, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    void
+    __insertion_sort(_RandomAccessIterator __first,
+		     _RandomAccessIterator __last, _Compare __comp)
+    {
+      if (__first == __last) return;
+
+      for (_RandomAccessIterator __i = __first + 1; __i != __last; ++__i)
+	{
+	  if (__comp(__i, __first))
+	    {
+	      typename iterator_traits<_RandomAccessIterator>::value_type
+		__val = _GLIBCXX_MOVE(*__i);
+	      _GLIBCXX_MOVE_BACKWARD3(__first, __i, __i + 1);
+	      *__first = _GLIBCXX_MOVE(__val);
+	    }
+	  else
+	    std::__unguarded_linear_insert(__i,
+				__gnu_cxx::__ops::__val_comp_iter(__comp));
+	}
+    }
+
+  /// This is a helper function for the sort routine.
+  template<typename _RandomAccessIterator, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    inline void
+    __unguarded_insertion_sort(_RandomAccessIterator __first,
+			       _RandomAccessIterator __last, _Compare __comp)
+    {
+      for (_RandomAccessIterator __i = __first; __i != __last; ++__i)
+	std::__unguarded_linear_insert(__i,
+				__gnu_cxx::__ops::__val_comp_iter(__comp));
+    }
+
+  /**
+   *  @doctodo
+   *  This controls some aspect of the sort routines.
+  */
+  enum { _S_threshold = 16 };
+
+  /// This is a helper function for the sort routine.
+  template<typename _RandomAccessIterator, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    void
+    __final_insertion_sort(_RandomAccessIterator __first,
+			   _RandomAccessIterator __last, _Compare __comp)
+    {
+      if (__last - __first > int(_S_threshold))
+	{
+	  std::__insertion_sort(__first, __first + int(_S_threshold), __comp);
+	  std::__unguarded_insertion_sort(__first + int(_S_threshold), __last,
+					  __comp);
+	}
+      else
+	std::__insertion_sort(__first, __last, __comp);
+    }
+
+  /// This is a helper function...
+  template<typename _RandomAccessIterator, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    _RandomAccessIterator
+    __unguarded_partition(_RandomAccessIterator __first,
+			  _RandomAccessIterator __last,
+			  _RandomAccessIterator __pivot, _Compare __comp)
+    {
+      while (true)
+	{
+	  while (__comp(__first, __pivot))
+	    ++__first;
+	  --__last;
+	  while (__comp(__pivot, __last))
+	    --__last;
+	  if (!(__first < __last))
+	    return __first;
+	  std::iter_swap(__first, __last);
+	  ++__first;
+	}
+    }
+
+  /// This is a helper function...
+  template<typename _RandomAccessIterator, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    inline _RandomAccessIterator
+    __unguarded_partition_pivot(_RandomAccessIterator __first,
+				_RandomAccessIterator __last, _Compare __comp)
+    {
+      _RandomAccessIterator __mid = __first + (__last - __first) / 2;
+      std::__move_median_to_first(__first, __first + 1, __mid, __last - 1,
+				  __comp);
+      return std::__unguarded_partition(__first + 1, __last, __first, __comp);
+    }
+
+  template<typename _RandomAccessIterator, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    inline void
+    __partial_sort(_RandomAccessIterator __first,
+		   _RandomAccessIterator __middle,
+		   _RandomAccessIterator __last,
+		   _Compare __comp)
+    {
+      std::__heap_select(__first, __middle, __last, __comp);
+      std::__sort_heap(__first, __middle, __comp);
+    }
+
+  /// This is a helper function for the sort routine.
+  template<typename _RandomAccessIterator, typename _Size, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    void
+    __introsort_loop(_RandomAccessIterator __first,
+		     _RandomAccessIterator __last,
+		     _Size __depth_limit, _Compare __comp)
+    {
+      while (__last - __first > int(_S_threshold))
+	{
+	  if (__depth_limit == 0)
+	    {
+	      std::__partial_sort(__first, __last, __last, __comp);
+	      return;
+	    }
+	  --__depth_limit;
+	  _RandomAccessIterator __cut =
+	    std::__unguarded_partition_pivot(__first, __last, __comp);
+	  std::__introsort_loop(__cut, __last, __depth_limit, __comp);
+	  __last = __cut;
+	}
+    }
+
+  // sort
+
+  template<typename _RandomAccessIterator, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    inline void
+    __sort(_RandomAccessIterator __first, _RandomAccessIterator __last,
+	   _Compare __comp)
+    {
+      if (__first != __last)
+	{
+	  std::__introsort_loop(__first, __last,
+				std::__lg(__last - __first) * 2,
+				__comp);
+	  std::__final_insertion_sort(__first, __last, __comp);
+	}
+    }
+
+  template<typename _RandomAccessIterator, typename _Size, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    void
+    __introselect(_RandomAccessIterator __first, _RandomAccessIterator __nth,
+		  _RandomAccessIterator __last, _Size __depth_limit,
+		  _Compare __comp)
+    {
+      while (__last - __first > 3)
+	{
+	  if (__depth_limit == 0)
+	    {
+	      std::__heap_select(__first, __nth + 1, __last, __comp);
+	      // Place the nth largest element in its final position.
+	      std::iter_swap(__first, __nth);
+	      return;
+	    }
+	  --__depth_limit;
+	  _RandomAccessIterator __cut =
+	    std::__unguarded_partition_pivot(__first, __last, __comp);
+	  if (__cut <= __nth)
+	    __first = __cut;
+	  else
+	    __last = __cut;
+	}
+      std::__insertion_sort(__first, __last, __comp);
+    }
+
+  // nth_element
+
+  // lower_bound moved to stl_algobase.h
+
+  /**
+   *  @brief Finds the first position in which @p __val could be inserted
+   *         without changing the ordering.
+   *  @ingroup binary_search_algorithms
+   *  @param  __first   An iterator.
+   *  @param  __last    Another iterator.
+   *  @param  __val     The search term.
+   *  @param  __comp    A functor to use for comparisons.
+   *  @return An iterator pointing to the first element <em>not less
+   *           than</em> @p __val, or end() if every element is less
+   *           than @p __val.
+   *  @ingroup binary_search_algorithms
+   *
+   *  The comparison function should have the same effects on ordering as
+   *  the function used for the initial sort.
+  */
+  template<typename _ForwardIterator, typename _Tp, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    inline _ForwardIterator
+    lower_bound(_ForwardIterator __first, _ForwardIterator __last,
+		const _Tp& __val, _Compare __comp)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
+	typename iterator_traits<_ForwardIterator>::value_type, _Tp>)
+      __glibcxx_requires_partitioned_lower_pred(__first, __last,
+						__val, __comp);
+
+      return std::__lower_bound(__first, __last, __val,
+				__gnu_cxx::__ops::__iter_comp_val(__comp));
+    }
+
+  template<typename _ForwardIterator, typename _Tp, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    _ForwardIterator
+    __upper_bound(_ForwardIterator __first, _ForwardIterator __last,
+		  const _Tp& __val, _Compare __comp)
+    {
+      typedef typename iterator_traits<_ForwardIterator>::difference_type
+	_DistanceType;
+
+      _DistanceType __len = std::distance(__first, __last);
+
+      while (__len > 0)
+	{
+	  _DistanceType __half = __len >> 1;
+	  _ForwardIterator __middle = __first;
+	  std::advance(__middle, __half);
+	  if (__comp(__val, __middle))
+	    __len = __half;
+	  else
+	    {
+	      __first = __middle;
+	      ++__first;
+	      __len = __len - __half - 1;
+	    }
+	}
+      return __first;
+    }
+
+  /**
+   *  @brief Finds the last position in which @p __val could be inserted
+   *         without changing the ordering.
+   *  @ingroup binary_search_algorithms
+   *  @param  __first   An iterator.
+   *  @param  __last    Another iterator.
+   *  @param  __val     The search term.
+   *  @return  An iterator pointing to the first element greater than @p __val,
+   *           or end() if no elements are greater than @p __val.
+   *  @ingroup binary_search_algorithms
+  */
+  template<typename _ForwardIterator, typename _Tp>
+    _GLIBCXX20_CONSTEXPR
+    inline _ForwardIterator
+    upper_bound(_ForwardIterator __first, _ForwardIterator __last,
+		const _Tp& __val)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+      __glibcxx_function_requires(_LessThanOpConcept<
+	_Tp, typename iterator_traits<_ForwardIterator>::value_type>)
+      __glibcxx_requires_partitioned_upper(__first, __last, __val);
+
+      return std::__upper_bound(__first, __last, __val,
+				__gnu_cxx::__ops::__val_less_iter());
+    }
+
+  /**
+   *  @brief Finds the last position in which @p __val could be inserted
+   *         without changing the ordering.
+   *  @ingroup binary_search_algorithms
+   *  @param  __first   An iterator.
+   *  @param  __last    Another iterator.
+   *  @param  __val     The search term.
+   *  @param  __comp    A functor to use for comparisons.
+   *  @return  An iterator pointing to the first element greater than @p __val,
+   *           or end() if no elements are greater than @p __val.
+   *  @ingroup binary_search_algorithms
+   *
+   *  The comparison function should have the same effects on ordering as
+   *  the function used for the initial sort.
+  */
+  template<typename _ForwardIterator, typename _Tp, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    inline _ForwardIterator
+    upper_bound(_ForwardIterator __first, _ForwardIterator __last,
+		const _Tp& __val, _Compare __comp)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
+	_Tp, typename iterator_traits<_ForwardIterator>::value_type>)
+      __glibcxx_requires_partitioned_upper_pred(__first, __last,
+						__val, __comp);
+
+      return std::__upper_bound(__first, __last, __val,
+				__gnu_cxx::__ops::__val_comp_iter(__comp));
+    }
+
+  template<typename _ForwardIterator, typename _Tp,
+	   typename _CompareItTp, typename _CompareTpIt>
+    _GLIBCXX20_CONSTEXPR
+    pair<_ForwardIterator, _ForwardIterator>
+    __equal_range(_ForwardIterator __first, _ForwardIterator __last,
+		  const _Tp& __val,
+		  _CompareItTp __comp_it_val, _CompareTpIt __comp_val_it)
+    {
+      typedef typename iterator_traits<_ForwardIterator>::difference_type
+	_DistanceType;
+
+      _DistanceType __len = std::distance(__first, __last);
+
+      while (__len > 0)
+	{
+	  _DistanceType __half = __len >> 1;
+	  _ForwardIterator __middle = __first;
+	  std::advance(__middle, __half);
+	  if (__comp_it_val(__middle, __val))
+	    {
+	      __first = __middle;
+	      ++__first;
+	      __len = __len - __half - 1;
+	    }
+	  else if (__comp_val_it(__val, __middle))
+	    __len = __half;
+	  else
+	    {
+	      _ForwardIterator __left
+		= std::__lower_bound(__first, __middle, __val, __comp_it_val);
+	      std::advance(__first, __len);
+	      _ForwardIterator __right
+		= std::__upper_bound(++__middle, __first, __val, __comp_val_it);
+	      return pair<_ForwardIterator, _ForwardIterator>(__left, __right);
+	    }
+	}
+      return pair<_ForwardIterator, _ForwardIterator>(__first, __first);
+    }
+
+  /**
+   *  @brief Finds the largest subrange in which @p __val could be inserted
+   *         at any place in it without changing the ordering.
+   *  @ingroup binary_search_algorithms
+   *  @param  __first   An iterator.
+   *  @param  __last    Another iterator.
+   *  @param  __val     The search term.
+   *  @return  An pair of iterators defining the subrange.
+   *  @ingroup binary_search_algorithms
+   *
+   *  This is equivalent to
+   *  @code
+   *    std::make_pair(lower_bound(__first, __last, __val),
+   *                   upper_bound(__first, __last, __val))
+   *  @endcode
+   *  but does not actually call those functions.
+  */
+  template<typename _ForwardIterator, typename _Tp>
+    _GLIBCXX20_CONSTEXPR
+    inline pair<_ForwardIterator, _ForwardIterator>
+    equal_range(_ForwardIterator __first, _ForwardIterator __last,
+		const _Tp& __val)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+      __glibcxx_function_requires(_LessThanOpConcept<
+	typename iterator_traits<_ForwardIterator>::value_type, _Tp>)
+      __glibcxx_function_requires(_LessThanOpConcept<
+	_Tp, typename iterator_traits<_ForwardIterator>::value_type>)
+      __glibcxx_requires_partitioned_lower(__first, __last, __val);
+      __glibcxx_requires_partitioned_upper(__first, __last, __val);
+
+      return std::__equal_range(__first, __last, __val,
+				__gnu_cxx::__ops::__iter_less_val(),
+				__gnu_cxx::__ops::__val_less_iter());
+    }
+
+  /**
+   *  @brief Finds the largest subrange in which @p __val could be inserted
+   *         at any place in it without changing the ordering.
+   *  @param  __first   An iterator.
+   *  @param  __last    Another iterator.
+   *  @param  __val     The search term.
+   *  @param  __comp    A functor to use for comparisons.
+   *  @return  An pair of iterators defining the subrange.
+   *  @ingroup binary_search_algorithms
+   *
+   *  This is equivalent to
+   *  @code
+   *    std::make_pair(lower_bound(__first, __last, __val, __comp),
+   *                   upper_bound(__first, __last, __val, __comp))
+   *  @endcode
+   *  but does not actually call those functions.
+  */
+  template<typename _ForwardIterator, typename _Tp, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    inline pair<_ForwardIterator, _ForwardIterator>
+    equal_range(_ForwardIterator __first, _ForwardIterator __last,
+		const _Tp& __val, _Compare __comp)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
+	typename iterator_traits<_ForwardIterator>::value_type, _Tp>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
+	_Tp, typename iterator_traits<_ForwardIterator>::value_type>)
+      __glibcxx_requires_partitioned_lower_pred(__first, __last,
+						__val, __comp);
+      __glibcxx_requires_partitioned_upper_pred(__first, __last,
+						__val, __comp);
+
+      return std::__equal_range(__first, __last, __val,
+				__gnu_cxx::__ops::__iter_comp_val(__comp),
+				__gnu_cxx::__ops::__val_comp_iter(__comp));
+    }
+
+  /**
+   *  @brief Determines whether an element exists in a range.
+   *  @ingroup binary_search_algorithms
+   *  @param  __first   An iterator.
+   *  @param  __last    Another iterator.
+   *  @param  __val     The search term.
+   *  @return True if @p __val (or its equivalent) is in [@p
+   *  __first,@p __last ].
+   *
+   *  Note that this does not actually return an iterator to @p __val.  For
+   *  that, use std::find or a container's specialized find member functions.
+  */
+  template<typename _ForwardIterator, typename _Tp>
+    _GLIBCXX20_CONSTEXPR
+    bool
+    binary_search(_ForwardIterator __first, _ForwardIterator __last,
+		  const _Tp& __val)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+      __glibcxx_function_requires(_LessThanOpConcept<
+	_Tp, typename iterator_traits<_ForwardIterator>::value_type>)
+      __glibcxx_requires_partitioned_lower(__first, __last, __val);
+      __glibcxx_requires_partitioned_upper(__first, __last, __val);
+
+      _ForwardIterator __i
+	= std::__lower_bound(__first, __last, __val,
+			     __gnu_cxx::__ops::__iter_less_val());
+      return __i != __last && !(__val < *__i);
+    }
+
+  /**
+   *  @brief Determines whether an element exists in a range.
+   *  @ingroup binary_search_algorithms
+   *  @param  __first   An iterator.
+   *  @param  __last    Another iterator.
+   *  @param  __val     The search term.
+   *  @param  __comp    A functor to use for comparisons.
+   *  @return  True if @p __val (or its equivalent) is in @p [__first,__last].
+   *
+   *  Note that this does not actually return an iterator to @p __val.  For
+   *  that, use std::find or a container's specialized find member functions.
+   *
+   *  The comparison function should have the same effects on ordering as
+   *  the function used for the initial sort.
+  */
+  template<typename _ForwardIterator, typename _Tp, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    bool
+    binary_search(_ForwardIterator __first, _ForwardIterator __last,
+		  const _Tp& __val, _Compare __comp)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
+	_Tp, typename iterator_traits<_ForwardIterator>::value_type>)
+      __glibcxx_requires_partitioned_lower_pred(__first, __last,
+						__val, __comp);
+      __glibcxx_requires_partitioned_upper_pred(__first, __last,
+						__val, __comp);
+
+      _ForwardIterator __i
+	= std::__lower_bound(__first, __last, __val,
+			     __gnu_cxx::__ops::__iter_comp_val(__comp));
+      return __i != __last && !bool(__comp(__val, *__i));
+    }
+
+  // merge
+
+  /// This is a helper function for the __merge_adaptive routines.
+  template<typename _InputIterator1, typename _InputIterator2,
+	   typename _OutputIterator, typename _Compare>
+    void
+    __move_merge_adaptive(_InputIterator1 __first1, _InputIterator1 __last1,
+			  _InputIterator2 __first2, _InputIterator2 __last2,
+			  _OutputIterator __result, _Compare __comp)
+    {
+      while (__first1 != __last1 && __first2 != __last2)
+	{
+	  if (__comp(__first2, __first1))
+	    {
+	      *__result = _GLIBCXX_MOVE(*__first2);
+	      ++__first2;
+	    }
+	  else
+	    {
+	      *__result = _GLIBCXX_MOVE(*__first1);
+	      ++__first1;
+	    }
+	  ++__result;
+	}
+      if (__first1 != __last1)
+	_GLIBCXX_MOVE3(__first1, __last1, __result);
+    }
+
+  /// This is a helper function for the __merge_adaptive routines.
+  template<typename _BidirectionalIterator1, typename _BidirectionalIterator2,
+	   typename _BidirectionalIterator3, typename _Compare>
+    void
+    __move_merge_adaptive_backward(_BidirectionalIterator1 __first1,
+				   _BidirectionalIterator1 __last1,
+				   _BidirectionalIterator2 __first2,
+				   _BidirectionalIterator2 __last2,
+				   _BidirectionalIterator3 __result,
+				   _Compare __comp)
+    {
+      if (__first1 == __last1)
+	{
+	  _GLIBCXX_MOVE_BACKWARD3(__first2, __last2, __result);
+	  return;
+	}
+      else if (__first2 == __last2)
+	return;
+
+      --__last1;
+      --__last2;
+      while (true)
+	{
+	  if (__comp(__last2, __last1))
+	    {
+	      *--__result = _GLIBCXX_MOVE(*__last1);
+	      if (__first1 == __last1)
+		{
+		  _GLIBCXX_MOVE_BACKWARD3(__first2, ++__last2, __result);
+		  return;
+		}
+	      --__last1;
+	    }
+	  else
+	    {
+	      *--__result = _GLIBCXX_MOVE(*__last2);
+	      if (__first2 == __last2)
+		return;
+	      --__last2;
+	    }
+	}
+    }
+
+  /// This is a helper function for the merge routines.
+  template<typename _BidirectionalIterator1, typename _BidirectionalIterator2,
+	   typename _Distance>
+    _BidirectionalIterator1
+    __rotate_adaptive(_BidirectionalIterator1 __first,
+		      _BidirectionalIterator1 __middle,
+		      _BidirectionalIterator1 __last,
+		      _Distance __len1, _Distance __len2,
+		      _BidirectionalIterator2 __buffer,
+		      _Distance __buffer_size)
+    {
+      _BidirectionalIterator2 __buffer_end;
+      if (__len1 > __len2 && __len2 <= __buffer_size)
+	{
+	  if (__len2)
+	    {
+	      __buffer_end = _GLIBCXX_MOVE3(__middle, __last, __buffer);
+	      _GLIBCXX_MOVE_BACKWARD3(__first, __middle, __last);
+	      return _GLIBCXX_MOVE3(__buffer, __buffer_end, __first);
+	    }
+	  else
+	    return __first;
+	}
+      else if (__len1 <= __buffer_size)
+	{
+	  if (__len1)
+	    {
+	      __buffer_end = _GLIBCXX_MOVE3(__first, __middle, __buffer);
+	      _GLIBCXX_MOVE3(__middle, __last, __first);
+	      return _GLIBCXX_MOVE_BACKWARD3(__buffer, __buffer_end, __last);
+	    }
+	  else
+	    return __last;
+	}
+      else
+	return std::rotate(__first, __middle, __last);
+    }
+
+  /// This is a helper function for the merge routines.
+  template<typename _BidirectionalIterator, typename _Distance, 
+	   typename _Pointer, typename _Compare>
+    void
+    __merge_adaptive(_BidirectionalIterator __first,
+		     _BidirectionalIterator __middle,
+		     _BidirectionalIterator __last,
+		     _Distance __len1, _Distance __len2,
+		     _Pointer __buffer, _Distance __buffer_size,
+		     _Compare __comp)
+    {
+      if (__len1 <= __len2 && __len1 <= __buffer_size)
+	{
+	  _Pointer __buffer_end = _GLIBCXX_MOVE3(__first, __middle, __buffer);
+	  std::__move_merge_adaptive(__buffer, __buffer_end, __middle, __last,
+				     __first, __comp);
+	}
+      else if (__len2 <= __buffer_size)
+	{
+	  _Pointer __buffer_end = _GLIBCXX_MOVE3(__middle, __last, __buffer);
+	  std::__move_merge_adaptive_backward(__first, __middle, __buffer,
+					      __buffer_end, __last, __comp);
+	}
+      else
+	{
+	  _BidirectionalIterator __first_cut = __first;
+	  _BidirectionalIterator __second_cut = __middle;
+	  _Distance __len11 = 0;
+	  _Distance __len22 = 0;
+	  if (__len1 > __len2)
+	    {
+	      __len11 = __len1 / 2;
+	      std::advance(__first_cut, __len11);
+	      __second_cut
+		= std::__lower_bound(__middle, __last, *__first_cut,
+				     __gnu_cxx::__ops::__iter_comp_val(__comp));
+	      __len22 = std::distance(__middle, __second_cut);
+	    }
+	  else
+	    {
+	      __len22 = __len2 / 2;
+	      std::advance(__second_cut, __len22);
+	      __first_cut
+		= std::__upper_bound(__first, __middle, *__second_cut,
+				     __gnu_cxx::__ops::__val_comp_iter(__comp));
+	      __len11 = std::distance(__first, __first_cut);
+	    }
+
+	  _BidirectionalIterator __new_middle
+	    = std::__rotate_adaptive(__first_cut, __middle, __second_cut,
+				     __len1 - __len11, __len22, __buffer,
+				     __buffer_size);
+	  std::__merge_adaptive(__first, __first_cut, __new_middle, __len11,
+				__len22, __buffer, __buffer_size, __comp);
+	  std::__merge_adaptive(__new_middle, __second_cut, __last,
+				__len1 - __len11,
+				__len2 - __len22, __buffer,
+				__buffer_size, __comp);
+	}
+    }
+
+  /// This is a helper function for the merge routines.
+  template<typename _BidirectionalIterator, typename _Distance,
+	   typename _Compare>
+    void
+    __merge_without_buffer(_BidirectionalIterator __first,
+			   _BidirectionalIterator __middle,
+			   _BidirectionalIterator __last,
+			   _Distance __len1, _Distance __len2,
+			   _Compare __comp)
+    {
+      if (__len1 == 0 || __len2 == 0)
+	return;
+
+      if (__len1 + __len2 == 2)
+	{
+	  if (__comp(__middle, __first))
+	    std::iter_swap(__first, __middle);
+	  return;
+	}
+
+      _BidirectionalIterator __first_cut = __first;
+      _BidirectionalIterator __second_cut = __middle;
+      _Distance __len11 = 0;
+      _Distance __len22 = 0;
+      if (__len1 > __len2)
+	{
+	  __len11 = __len1 / 2;
+	  std::advance(__first_cut, __len11);
+	  __second_cut
+	    = std::__lower_bound(__middle, __last, *__first_cut,
+				 __gnu_cxx::__ops::__iter_comp_val(__comp));
+	  __len22 = std::distance(__middle, __second_cut);
+	}
+      else
+	{
+	  __len22 = __len2 / 2;
+	  std::advance(__second_cut, __len22);
+	  __first_cut
+	    = std::__upper_bound(__first, __middle, *__second_cut,
+				 __gnu_cxx::__ops::__val_comp_iter(__comp));
+	  __len11 = std::distance(__first, __first_cut);
+	}
+
+      _BidirectionalIterator __new_middle
+	= std::rotate(__first_cut, __middle, __second_cut);
+      std::__merge_without_buffer(__first, __first_cut, __new_middle,
+				  __len11, __len22, __comp);
+      std::__merge_without_buffer(__new_middle, __second_cut, __last,
+				  __len1 - __len11, __len2 - __len22, __comp);
+    }
+
+  template<typename _BidirectionalIterator, typename _Compare>
+    void
+    __inplace_merge(_BidirectionalIterator __first,
+		    _BidirectionalIterator __middle,
+		    _BidirectionalIterator __last,
+		    _Compare __comp)
+    {
+      typedef typename iterator_traits<_BidirectionalIterator>::value_type
+	  _ValueType;
+      typedef typename iterator_traits<_BidirectionalIterator>::difference_type
+	  _DistanceType;
+      typedef _Temporary_buffer<_BidirectionalIterator, _ValueType> _TmpBuf;
+
+      if (__first == __middle || __middle == __last)
+	return;
+
+      const _DistanceType __len1 = std::distance(__first, __middle);
+      const _DistanceType __len2 = std::distance(__middle, __last);
+
+      // __merge_adaptive will use a buffer for the smaller of
+      // [first,middle) and [middle,last).
+      _TmpBuf __buf(__first, std::min(__len1, __len2));
+
+      if (__buf.begin() == 0)
+	std::__merge_without_buffer
+	  (__first, __middle, __last, __len1, __len2, __comp);
+      else
+	std::__merge_adaptive
+	  (__first, __middle, __last, __len1, __len2, __buf.begin(),
+	   _DistanceType(__buf.size()), __comp);
+    }
+
+  /**
+   *  @brief Merges two sorted ranges in place.
+   *  @ingroup sorting_algorithms
+   *  @param  __first   An iterator.
+   *  @param  __middle  Another iterator.
+   *  @param  __last    Another iterator.
+   *  @return  Nothing.
+   *
+   *  Merges two sorted and consecutive ranges, [__first,__middle) and
+   *  [__middle,__last), and puts the result in [__first,__last).  The
+   *  output will be sorted.  The sort is @e stable, that is, for
+   *  equivalent elements in the two ranges, elements from the first
+   *  range will always come before elements from the second.
+   *
+   *  If enough additional memory is available, this takes (__last-__first)-1
+   *  comparisons.  Otherwise an NlogN algorithm is used, where N is
+   *  distance(__first,__last).
+  */
+  template<typename _BidirectionalIterator>
+    inline void
+    inplace_merge(_BidirectionalIterator __first,
+		  _BidirectionalIterator __middle,
+		  _BidirectionalIterator __last)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_Mutable_BidirectionalIteratorConcept<
+	    _BidirectionalIterator>)
+      __glibcxx_function_requires(_LessThanComparableConcept<
+	    typename iterator_traits<_BidirectionalIterator>::value_type>)
+      __glibcxx_requires_sorted(__first, __middle);
+      __glibcxx_requires_sorted(__middle, __last);
+      __glibcxx_requires_irreflexive(__first, __last);
+
+      std::__inplace_merge(__first, __middle, __last,
+			   __gnu_cxx::__ops::__iter_less_iter());
+    }
+
+  /**
+   *  @brief Merges two sorted ranges in place.
+   *  @ingroup sorting_algorithms
+   *  @param  __first   An iterator.
+   *  @param  __middle  Another iterator.
+   *  @param  __last    Another iterator.
+   *  @param  __comp    A functor to use for comparisons.
+   *  @return  Nothing.
+   *
+   *  Merges two sorted and consecutive ranges, [__first,__middle) and
+   *  [middle,last), and puts the result in [__first,__last).  The output will
+   *  be sorted.  The sort is @e stable, that is, for equivalent
+   *  elements in the two ranges, elements from the first range will always
+   *  come before elements from the second.
+   *
+   *  If enough additional memory is available, this takes (__last-__first)-1
+   *  comparisons.  Otherwise an NlogN algorithm is used, where N is
+   *  distance(__first,__last).
+   *
+   *  The comparison function should have the same effects on ordering as
+   *  the function used for the initial sort.
+  */
+  template<typename _BidirectionalIterator, typename _Compare>
+    inline void
+    inplace_merge(_BidirectionalIterator __first,
+		  _BidirectionalIterator __middle,
+		  _BidirectionalIterator __last,
+		  _Compare __comp)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_Mutable_BidirectionalIteratorConcept<
+	    _BidirectionalIterator>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
+	    typename iterator_traits<_BidirectionalIterator>::value_type,
+	    typename iterator_traits<_BidirectionalIterator>::value_type>)
+      __glibcxx_requires_sorted_pred(__first, __middle, __comp);
+      __glibcxx_requires_sorted_pred(__middle, __last, __comp);
+      __glibcxx_requires_irreflexive_pred(__first, __last, __comp);
+
+      std::__inplace_merge(__first, __middle, __last,
+			   __gnu_cxx::__ops::__iter_comp_iter(__comp));
+    }
+
+
+  /// This is a helper function for the __merge_sort_loop routines.
+  template<typename _InputIterator, typename _OutputIterator,
+	   typename _Compare>
+    _OutputIterator
+    __move_merge(_InputIterator __first1, _InputIterator __last1,
+		 _InputIterator __first2, _InputIterator __last2,
+		 _OutputIterator __result, _Compare __comp)
+    {
+      while (__first1 != __last1 && __first2 != __last2)
+	{
+	  if (__comp(__first2, __first1))
+	    {
+	      *__result = _GLIBCXX_MOVE(*__first2);
+	      ++__first2;
+	    }
+	  else
+	    {
+	      *__result = _GLIBCXX_MOVE(*__first1);
+	      ++__first1;
+	    }
+	  ++__result;
+	}
+      return _GLIBCXX_MOVE3(__first2, __last2,
+			    _GLIBCXX_MOVE3(__first1, __last1,
+					   __result));
+    }
+
+  template<typename _RandomAccessIterator1, typename _RandomAccessIterator2,
+	   typename _Distance, typename _Compare>
+    void
+    __merge_sort_loop(_RandomAccessIterator1 __first,
+		      _RandomAccessIterator1 __last,
+		      _RandomAccessIterator2 __result, _Distance __step_size,
+		      _Compare __comp)
+    {
+      const _Distance __two_step = 2 * __step_size;
+
+      while (__last - __first >= __two_step)
+	{
+	  __result = std::__move_merge(__first, __first + __step_size,
+				       __first + __step_size,
+				       __first + __two_step,
+				       __result, __comp);
+	  __first += __two_step;
+	}
+      __step_size = std::min(_Distance(__last - __first), __step_size);
+
+      std::__move_merge(__first, __first + __step_size,
+			__first + __step_size, __last, __result, __comp);
+    }
+
+  template<typename _RandomAccessIterator, typename _Distance,
+	   typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    void
+    __chunk_insertion_sort(_RandomAccessIterator __first,
+			   _RandomAccessIterator __last,
+			   _Distance __chunk_size, _Compare __comp)
+    {
+      while (__last - __first >= __chunk_size)
+	{
+	  std::__insertion_sort(__first, __first + __chunk_size, __comp);
+	  __first += __chunk_size;
+	}
+      std::__insertion_sort(__first, __last, __comp);
+    }
+
+  enum { _S_chunk_size = 7 };
+
+  template<typename _RandomAccessIterator, typename _Pointer, typename _Compare>
+    void
+    __merge_sort_with_buffer(_RandomAccessIterator __first,
+			     _RandomAccessIterator __last,
+			     _Pointer __buffer, _Compare __comp)
+    {
+      typedef typename iterator_traits<_RandomAccessIterator>::difference_type
+	_Distance;
+
+      const _Distance __len = __last - __first;
+      const _Pointer __buffer_last = __buffer + __len;
+
+      _Distance __step_size = _S_chunk_size;
+      std::__chunk_insertion_sort(__first, __last, __step_size, __comp);
+
+      while (__step_size < __len)
+	{
+	  std::__merge_sort_loop(__first, __last, __buffer,
+				 __step_size, __comp);
+	  __step_size *= 2;
+	  std::__merge_sort_loop(__buffer, __buffer_last, __first,
+				 __step_size, __comp);
+	  __step_size *= 2;
+	}
+    }
+
+  template<typename _RandomAccessIterator, typename _Pointer,
+	   typename _Distance, typename _Compare>
+    void
+    __stable_sort_adaptive(_RandomAccessIterator __first,
+			   _RandomAccessIterator __last,
+			   _Pointer __buffer, _Distance __buffer_size,
+			   _Compare __comp)
+    {
+      const _Distance __len = (__last - __first + 1) / 2;
+      const _RandomAccessIterator __middle = __first + __len;
+      if (__len > __buffer_size)
+	{
+	  std::__stable_sort_adaptive(__first, __middle, __buffer,
+				      __buffer_size, __comp);
+	  std::__stable_sort_adaptive(__middle, __last, __buffer,
+				      __buffer_size, __comp);
+	}
+      else
+	{
+	  std::__merge_sort_with_buffer(__first, __middle, __buffer, __comp);
+	  std::__merge_sort_with_buffer(__middle, __last, __buffer, __comp);
+	}
+
+      std::__merge_adaptive(__first, __middle, __last,
+			    _Distance(__middle - __first),
+			    _Distance(__last - __middle),
+			    __buffer, __buffer_size,
+			    __comp);
+    }
+
+  /// This is a helper function for the stable sorting routines.
+  template<typename _RandomAccessIterator, typename _Compare>
+    void
+    __inplace_stable_sort(_RandomAccessIterator __first,
+			  _RandomAccessIterator __last, _Compare __comp)
+    {
+      if (__last - __first < 15)
+	{
+	  std::__insertion_sort(__first, __last, __comp);
+	  return;
+	}
+      _RandomAccessIterator __middle = __first + (__last - __first) / 2;
+      std::__inplace_stable_sort(__first, __middle, __comp);
+      std::__inplace_stable_sort(__middle, __last, __comp);
+      std::__merge_without_buffer(__first, __middle, __last,
+				  __middle - __first,
+				  __last - __middle,
+				  __comp);
+    }
+
+  // stable_sort
+
+  // Set algorithms: includes, set_union, set_intersection, set_difference,
+  // set_symmetric_difference.  All of these algorithms have the precondition
+  // that their input ranges are sorted and the postcondition that their output
+  // ranges are sorted.
+
+  template<typename _InputIterator1, typename _InputIterator2,
+	   typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    bool
+    __includes(_InputIterator1 __first1, _InputIterator1 __last1,
+	       _InputIterator2 __first2, _InputIterator2 __last2,
+	       _Compare __comp)
+    {
+      while (__first1 != __last1 && __first2 != __last2)
+	{
+	  if (__comp(__first2, __first1))
+	    return false;
+	  if (!__comp(__first1, __first2))
+	    ++__first2;
+	  ++__first1;
+	}
+
+      return __first2 == __last2;
+    }
+
+  /**
+   *  @brief Determines whether all elements of a sequence exists in a range.
+   *  @param  __first1  Start of search range.
+   *  @param  __last1   End of search range.
+   *  @param  __first2  Start of sequence
+   *  @param  __last2   End of sequence.
+   *  @return  True if each element in [__first2,__last2) is contained in order
+   *  within [__first1,__last1).  False otherwise.
+   *  @ingroup set_algorithms
+   *
+   *  This operation expects both [__first1,__last1) and
+   *  [__first2,__last2) to be sorted.  Searches for the presence of
+   *  each element in [__first2,__last2) within [__first1,__last1).
+   *  The iterators over each range only move forward, so this is a
+   *  linear algorithm.  If an element in [__first2,__last2) is not
+   *  found before the search iterator reaches @p __last2, false is
+   *  returned.
+  */
+  template<typename _InputIterator1, typename _InputIterator2>
+    _GLIBCXX20_CONSTEXPR
+    inline bool
+    includes(_InputIterator1 __first1, _InputIterator1 __last1,
+	     _InputIterator2 __first2, _InputIterator2 __last2)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
+      __glibcxx_function_requires(_LessThanOpConcept<
+	    typename iterator_traits<_InputIterator1>::value_type,
+	    typename iterator_traits<_InputIterator2>::value_type>)
+      __glibcxx_function_requires(_LessThanOpConcept<
+	    typename iterator_traits<_InputIterator2>::value_type,
+	    typename iterator_traits<_InputIterator1>::value_type>)
+      __glibcxx_requires_sorted_set(__first1, __last1, __first2);
+      __glibcxx_requires_sorted_set(__first2, __last2, __first1);
+      __glibcxx_requires_irreflexive2(__first1, __last1);
+      __glibcxx_requires_irreflexive2(__first2, __last2);
+
+      return std::__includes(__first1, __last1, __first2, __last2,
+			     __gnu_cxx::__ops::__iter_less_iter());
+    }
+
+  /**
+   *  @brief Determines whether all elements of a sequence exists in a range
+   *  using comparison.
+   *  @ingroup set_algorithms
+   *  @param  __first1  Start of search range.
+   *  @param  __last1   End of search range.
+   *  @param  __first2  Start of sequence
+   *  @param  __last2   End of sequence.
+   *  @param  __comp    Comparison function to use.
+   *  @return True if each element in [__first2,__last2) is contained
+   *  in order within [__first1,__last1) according to comp.  False
+   *  otherwise.  @ingroup set_algorithms
+   *
+   *  This operation expects both [__first1,__last1) and
+   *  [__first2,__last2) to be sorted.  Searches for the presence of
+   *  each element in [__first2,__last2) within [__first1,__last1),
+   *  using comp to decide.  The iterators over each range only move
+   *  forward, so this is a linear algorithm.  If an element in
+   *  [__first2,__last2) is not found before the search iterator
+   *  reaches @p __last2, false is returned.
+  */
+  template<typename _InputIterator1, typename _InputIterator2,
+	   typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    inline bool
+    includes(_InputIterator1 __first1, _InputIterator1 __last1,
+	     _InputIterator2 __first2, _InputIterator2 __last2,
+	     _Compare __comp)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
+	    typename iterator_traits<_InputIterator1>::value_type,
+	    typename iterator_traits<_InputIterator2>::value_type>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
+	    typename iterator_traits<_InputIterator2>::value_type,
+	    typename iterator_traits<_InputIterator1>::value_type>)
+      __glibcxx_requires_sorted_set_pred(__first1, __last1, __first2, __comp);
+      __glibcxx_requires_sorted_set_pred(__first2, __last2, __first1, __comp);
+      __glibcxx_requires_irreflexive_pred2(__first1, __last1, __comp);
+      __glibcxx_requires_irreflexive_pred2(__first2, __last2, __comp);
+
+      return std::__includes(__first1, __last1, __first2, __last2,
+			     __gnu_cxx::__ops::__iter_comp_iter(__comp));
+    }
+
+  // nth_element
+  // merge
+  // set_difference
+  // set_intersection
+  // set_union
+  // stable_sort
+  // set_symmetric_difference
+  // min_element
+  // max_element
+
+  template<typename _BidirectionalIterator, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    bool
+    __next_permutation(_BidirectionalIterator __first,
+		       _BidirectionalIterator __last, _Compare __comp)
+    {
+      if (__first == __last)
+	return false;
+      _BidirectionalIterator __i = __first;
+      ++__i;
+      if (__i == __last)
+	return false;
+      __i = __last;
+      --__i;
+
+      for(;;)
+	{
+	  _BidirectionalIterator __ii = __i;
+	  --__i;
+	  if (__comp(__i, __ii))
+	    {
+	      _BidirectionalIterator __j = __last;
+	      while (!__comp(__i, --__j))
+		{}
+	      std::iter_swap(__i, __j);
+	      std::__reverse(__ii, __last,
+			     std::__iterator_category(__first));
+	      return true;
+	    }
+	  if (__i == __first)
+	    {
+	      std::__reverse(__first, __last,
+			     std::__iterator_category(__first));
+	      return false;
+	    }
+	}
+    }
+
+  /**
+   *  @brief  Permute range into the next @e dictionary ordering.
+   *  @ingroup sorting_algorithms
+   *  @param  __first  Start of range.
+   *  @param  __last   End of range.
+   *  @return  False if wrapped to first permutation, true otherwise.
+   *
+   *  Treats all permutations of the range as a set of @e dictionary sorted
+   *  sequences.  Permutes the current sequence into the next one of this set.
+   *  Returns true if there are more sequences to generate.  If the sequence
+   *  is the largest of the set, the smallest is generated and false returned.
+  */
+  template<typename _BidirectionalIterator>
+    _GLIBCXX20_CONSTEXPR
+    inline bool
+    next_permutation(_BidirectionalIterator __first,
+		     _BidirectionalIterator __last)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_BidirectionalIteratorConcept<
+				  _BidirectionalIterator>)
+      __glibcxx_function_requires(_LessThanComparableConcept<
+	    typename iterator_traits<_BidirectionalIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+      __glibcxx_requires_irreflexive(__first, __last);
+
+      return std::__next_permutation
+	(__first, __last, __gnu_cxx::__ops::__iter_less_iter());
+    }
+
+  /**
+   *  @brief  Permute range into the next @e dictionary ordering using
+   *          comparison functor.
+   *  @ingroup sorting_algorithms
+   *  @param  __first  Start of range.
+   *  @param  __last   End of range.
+   *  @param  __comp   A comparison functor.
+   *  @return  False if wrapped to first permutation, true otherwise.
+   *
+   *  Treats all permutations of the range [__first,__last) as a set of
+   *  @e dictionary sorted sequences ordered by @p __comp.  Permutes the current
+   *  sequence into the next one of this set.  Returns true if there are more
+   *  sequences to generate.  If the sequence is the largest of the set, the
+   *  smallest is generated and false returned.
+  */
+  template<typename _BidirectionalIterator, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    inline bool
+    next_permutation(_BidirectionalIterator __first,
+		     _BidirectionalIterator __last, _Compare __comp)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_BidirectionalIteratorConcept<
+				  _BidirectionalIterator>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
+	    typename iterator_traits<_BidirectionalIterator>::value_type,
+	    typename iterator_traits<_BidirectionalIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+      __glibcxx_requires_irreflexive_pred(__first, __last, __comp);
+
+      return std::__next_permutation
+	(__first, __last, __gnu_cxx::__ops::__iter_comp_iter(__comp));
+    }
+
+  template<typename _BidirectionalIterator, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    bool
+    __prev_permutation(_BidirectionalIterator __first,
+		       _BidirectionalIterator __last, _Compare __comp)
+    {
+      if (__first == __last)
+	return false;
+      _BidirectionalIterator __i = __first;
+      ++__i;
+      if (__i == __last)
+	return false;
+      __i = __last;
+      --__i;
+
+      for(;;)
+	{
+	  _BidirectionalIterator __ii = __i;
+	  --__i;
+	  if (__comp(__ii, __i))
+	    {
+	      _BidirectionalIterator __j = __last;
+	      while (!__comp(--__j, __i))
+		{}
+	      std::iter_swap(__i, __j);
+	      std::__reverse(__ii, __last,
+			     std::__iterator_category(__first));
+	      return true;
+	    }
+	  if (__i == __first)
+	    {
+	      std::__reverse(__first, __last,
+			     std::__iterator_category(__first));
+	      return false;
+	    }
+	}
+    }
+
+  /**
+   *  @brief  Permute range into the previous @e dictionary ordering.
+   *  @ingroup sorting_algorithms
+   *  @param  __first  Start of range.
+   *  @param  __last   End of range.
+   *  @return  False if wrapped to last permutation, true otherwise.
+   *
+   *  Treats all permutations of the range as a set of @e dictionary sorted
+   *  sequences.  Permutes the current sequence into the previous one of this
+   *  set.  Returns true if there are more sequences to generate.  If the
+   *  sequence is the smallest of the set, the largest is generated and false
+   *  returned.
+  */
+  template<typename _BidirectionalIterator>
+    _GLIBCXX20_CONSTEXPR
+    inline bool
+    prev_permutation(_BidirectionalIterator __first,
+		     _BidirectionalIterator __last)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_BidirectionalIteratorConcept<
+				  _BidirectionalIterator>)
+      __glibcxx_function_requires(_LessThanComparableConcept<
+	    typename iterator_traits<_BidirectionalIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+      __glibcxx_requires_irreflexive(__first, __last);
+
+      return std::__prev_permutation(__first, __last,
+				     __gnu_cxx::__ops::__iter_less_iter());
+    }
+
+  /**
+   *  @brief  Permute range into the previous @e dictionary ordering using
+   *          comparison functor.
+   *  @ingroup sorting_algorithms
+   *  @param  __first  Start of range.
+   *  @param  __last   End of range.
+   *  @param  __comp   A comparison functor.
+   *  @return  False if wrapped to last permutation, true otherwise.
+   *
+   *  Treats all permutations of the range [__first,__last) as a set of
+   *  @e dictionary sorted sequences ordered by @p __comp.  Permutes the current
+   *  sequence into the previous one of this set.  Returns true if there are
+   *  more sequences to generate.  If the sequence is the smallest of the set,
+   *  the largest is generated and false returned.
+  */
+  template<typename _BidirectionalIterator, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    inline bool
+    prev_permutation(_BidirectionalIterator __first,
+		     _BidirectionalIterator __last, _Compare __comp)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_BidirectionalIteratorConcept<
+				  _BidirectionalIterator>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
+	    typename iterator_traits<_BidirectionalIterator>::value_type,
+	    typename iterator_traits<_BidirectionalIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+      __glibcxx_requires_irreflexive_pred(__first, __last, __comp);
+
+      return std::__prev_permutation(__first, __last,
+				__gnu_cxx::__ops::__iter_comp_iter(__comp));
+    }
+
+  // replace
+  // replace_if
+
+  template<typename _InputIterator, typename _OutputIterator,
+	   typename _Predicate, typename _Tp>
+    _GLIBCXX20_CONSTEXPR
+    _OutputIterator
+    __replace_copy_if(_InputIterator __first, _InputIterator __last,
+		      _OutputIterator __result,
+		      _Predicate __pred, const _Tp& __new_value)
+    {
+      for (; __first != __last; ++__first, (void)++__result)
+	if (__pred(__first))
+	  *__result = __new_value;
+	else
+	  *__result = *__first;
+      return __result;
+    }
+
+  /**
+   *  @brief Copy a sequence, replacing each element of one value with another
+   *         value.
+   *  @param  __first      An input iterator.
+   *  @param  __last       An input iterator.
+   *  @param  __result     An output iterator.
+   *  @param  __old_value  The value to be replaced.
+   *  @param  __new_value  The replacement value.
+   *  @return   The end of the output sequence, @p result+(last-first).
+   *
+   *  Copies each element in the input range @p [__first,__last) to the
+   *  output range @p [__result,__result+(__last-__first)) replacing elements
+   *  equal to @p __old_value with @p __new_value.
+  */
+  template<typename _InputIterator, typename _OutputIterator, typename _Tp>
+    _GLIBCXX20_CONSTEXPR
+    inline _OutputIterator
+    replace_copy(_InputIterator __first, _InputIterator __last,
+		 _OutputIterator __result,
+		 const _Tp& __old_value, const _Tp& __new_value)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
+	    typename iterator_traits<_InputIterator>::value_type>)
+      __glibcxx_function_requires(_EqualOpConcept<
+	    typename iterator_traits<_InputIterator>::value_type, _Tp>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      return std::__replace_copy_if(__first, __last, __result,
+			__gnu_cxx::__ops::__iter_equals_val(__old_value),
+					      __new_value);
+    }
+
+  /**
+   *  @brief Copy a sequence, replacing each value for which a predicate
+   *         returns true with another value.
+   *  @ingroup mutating_algorithms
+   *  @param  __first      An input iterator.
+   *  @param  __last       An input iterator.
+   *  @param  __result     An output iterator.
+   *  @param  __pred       A predicate.
+   *  @param  __new_value  The replacement value.
+   *  @return   The end of the output sequence, @p __result+(__last-__first).
+   *
+   *  Copies each element in the range @p [__first,__last) to the range
+   *  @p [__result,__result+(__last-__first)) replacing elements for which
+   *  @p __pred returns true with @p __new_value.
+  */
+  template<typename _InputIterator, typename _OutputIterator,
+	   typename _Predicate, typename _Tp>
+    _GLIBCXX20_CONSTEXPR
+    inline _OutputIterator
+    replace_copy_if(_InputIterator __first, _InputIterator __last,
+		    _OutputIterator __result,
+		    _Predicate __pred, const _Tp& __new_value)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
+	    typename iterator_traits<_InputIterator>::value_type>)
+      __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,
+	    typename iterator_traits<_InputIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      return std::__replace_copy_if(__first, __last, __result,
+				__gnu_cxx::__ops::__pred_iter(__pred),
+					      __new_value);
+    }
+
+#if __cplusplus >= 201103L
+  /**
+   *  @brief  Determines whether the elements of a sequence are sorted.
+   *  @ingroup sorting_algorithms
+   *  @param  __first   An iterator.
+   *  @param  __last    Another iterator.
+   *  @return  True if the elements are sorted, false otherwise.
+  */
+  template<typename _ForwardIterator>
+    _GLIBCXX20_CONSTEXPR
+    inline bool
+    is_sorted(_ForwardIterator __first, _ForwardIterator __last)
+    { return std::is_sorted_until(__first, __last) == __last; }
+
+  /**
+   *  @brief  Determines whether the elements of a sequence are sorted
+   *          according to a comparison functor.
+   *  @ingroup sorting_algorithms
+   *  @param  __first   An iterator.
+   *  @param  __last    Another iterator.
+   *  @param  __comp    A comparison functor.
+   *  @return  True if the elements are sorted, false otherwise.
+  */
+  template<typename _ForwardIterator, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    inline bool
+    is_sorted(_ForwardIterator __first, _ForwardIterator __last,
+	      _Compare __comp)
+    { return std::is_sorted_until(__first, __last, __comp) == __last; }
+
+  template<typename _ForwardIterator, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    _ForwardIterator
+    __is_sorted_until(_ForwardIterator __first, _ForwardIterator __last,
+		      _Compare __comp)
+    {
+      if (__first == __last)
+	return __last;
+
+      _ForwardIterator __next = __first;
+      for (++__next; __next != __last; __first = __next, (void)++__next)
+	if (__comp(__next, __first))
+	  return __next;
+      return __next;
+    }
+
+  /**
+   *  @brief  Determines the end of a sorted sequence.
+   *  @ingroup sorting_algorithms
+   *  @param  __first   An iterator.
+   *  @param  __last    Another iterator.
+   *  @return  An iterator pointing to the last iterator i in [__first, __last)
+   *           for which the range [__first, i) is sorted.
+  */
+  template<typename _ForwardIterator>
+    _GLIBCXX20_CONSTEXPR
+    inline _ForwardIterator
+    is_sorted_until(_ForwardIterator __first, _ForwardIterator __last)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+      __glibcxx_function_requires(_LessThanComparableConcept<
+	    typename iterator_traits<_ForwardIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+      __glibcxx_requires_irreflexive(__first, __last);
+
+      return std::__is_sorted_until(__first, __last,
+				    __gnu_cxx::__ops::__iter_less_iter());
+    }
+
+  /**
+   *  @brief  Determines the end of a sorted sequence using comparison functor.
+   *  @ingroup sorting_algorithms
+   *  @param  __first   An iterator.
+   *  @param  __last    Another iterator.
+   *  @param  __comp    A comparison functor.
+   *  @return  An iterator pointing to the last iterator i in [__first, __last)
+   *           for which the range [__first, i) is sorted.
+  */
+  template<typename _ForwardIterator, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    inline _ForwardIterator
+    is_sorted_until(_ForwardIterator __first, _ForwardIterator __last,
+		    _Compare __comp)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
+	    typename iterator_traits<_ForwardIterator>::value_type,
+	    typename iterator_traits<_ForwardIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+      __glibcxx_requires_irreflexive_pred(__first, __last, __comp);
+
+      return std::__is_sorted_until(__first, __last,
+				    __gnu_cxx::__ops::__iter_comp_iter(__comp));
+    }
+
+  /**
+   *  @brief  Determines min and max at once as an ordered pair.
+   *  @ingroup sorting_algorithms
+   *  @param  __a  A thing of arbitrary type.
+   *  @param  __b  Another thing of arbitrary type.
+   *  @return A pair(__b, __a) if __b is smaller than __a, pair(__a,
+   *  __b) otherwise.
+  */
+  template<typename _Tp>
+    _GLIBCXX14_CONSTEXPR
+    inline pair<const _Tp&, const _Tp&>
+    minmax(const _Tp& __a, const _Tp& __b)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_LessThanComparableConcept<_Tp>)
+
+      return __b < __a ? pair<const _Tp&, const _Tp&>(__b, __a)
+		       : pair<const _Tp&, const _Tp&>(__a, __b);
+    }
+
+  /**
+   *  @brief  Determines min and max at once as an ordered pair.
+   *  @ingroup sorting_algorithms
+   *  @param  __a  A thing of arbitrary type.
+   *  @param  __b  Another thing of arbitrary type.
+   *  @param  __comp  A @link comparison_functors comparison functor @endlink.
+   *  @return A pair(__b, __a) if __b is smaller than __a, pair(__a,
+   *  __b) otherwise.
+  */
+  template<typename _Tp, typename _Compare>
+    _GLIBCXX14_CONSTEXPR
+    inline pair<const _Tp&, const _Tp&>
+    minmax(const _Tp& __a, const _Tp& __b, _Compare __comp)
+    {
+      return __comp(__b, __a) ? pair<const _Tp&, const _Tp&>(__b, __a)
+			      : pair<const _Tp&, const _Tp&>(__a, __b);
+    }
+
+  template<typename _ForwardIterator, typename _Compare>
+    _GLIBCXX14_CONSTEXPR
+    pair<_ForwardIterator, _ForwardIterator>
+    __minmax_element(_ForwardIterator __first, _ForwardIterator __last,
+		     _Compare __comp)
+    {
+      _ForwardIterator __next = __first;
+      if (__first == __last
+	  || ++__next == __last)
+	return std::make_pair(__first, __first);
+
+      _ForwardIterator __min{}, __max{};
+      if (__comp(__next, __first))
+	{
+	  __min = __next;
+	  __max = __first;
+	}
+      else
+	{
+	  __min = __first;
+	  __max = __next;
+	}
+
+      __first = __next;
+      ++__first;
+
+      while (__first != __last)
+	{
+	  __next = __first;
+	  if (++__next == __last)
+	    {
+	      if (__comp(__first, __min))
+		__min = __first;
+	      else if (!__comp(__first, __max))
+		__max = __first;
+	      break;
+	    }
+
+	  if (__comp(__next, __first))
+	    {
+	      if (__comp(__next, __min))
+		__min = __next;
+	      if (!__comp(__first, __max))
+		__max = __first;
+	    }
+	  else
+	    {
+	      if (__comp(__first, __min))
+		__min = __first;
+	      if (!__comp(__next, __max))
+		__max = __next;
+	    }
+
+	  __first = __next;
+	  ++__first;
+	}
+
+      return std::make_pair(__min, __max);
+    }
+
+  /**
+   *  @brief  Return a pair of iterators pointing to the minimum and maximum
+   *          elements in a range.
+   *  @ingroup sorting_algorithms
+   *  @param  __first  Start of range.
+   *  @param  __last   End of range.
+   *  @return  make_pair(m, M), where m is the first iterator i in 
+   *           [__first, __last) such that no other element in the range is
+   *           smaller, and where M is the last iterator i in [__first, __last)
+   *           such that no other element in the range is larger.
+  */
+  template<typename _ForwardIterator>
+    _GLIBCXX14_CONSTEXPR
+    inline pair<_ForwardIterator, _ForwardIterator>
+    minmax_element(_ForwardIterator __first, _ForwardIterator __last)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+      __glibcxx_function_requires(_LessThanComparableConcept<
+	    typename iterator_traits<_ForwardIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+      __glibcxx_requires_irreflexive(__first, __last);
+
+      return std::__minmax_element(__first, __last,
+				   __gnu_cxx::__ops::__iter_less_iter());
+    }
+
+  /**
+   *  @brief  Return a pair of iterators pointing to the minimum and maximum
+   *          elements in a range.
+   *  @ingroup sorting_algorithms
+   *  @param  __first  Start of range.
+   *  @param  __last   End of range.
+   *  @param  __comp   Comparison functor.
+   *  @return  make_pair(m, M), where m is the first iterator i in 
+   *           [__first, __last) such that no other element in the range is
+   *           smaller, and where M is the last iterator i in [__first, __last)
+   *           such that no other element in the range is larger.
+  */
+  template<typename _ForwardIterator, typename _Compare>
+    _GLIBCXX14_CONSTEXPR
+    inline pair<_ForwardIterator, _ForwardIterator>
+    minmax_element(_ForwardIterator __first, _ForwardIterator __last,
+		   _Compare __comp)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
+	    typename iterator_traits<_ForwardIterator>::value_type,
+	    typename iterator_traits<_ForwardIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+      __glibcxx_requires_irreflexive_pred(__first, __last, __comp);
+
+      return std::__minmax_element(__first, __last,
+				   __gnu_cxx::__ops::__iter_comp_iter(__comp));
+    }
+
+  template<typename _Tp>
+    _GLIBCXX14_CONSTEXPR
+    inline pair<_Tp, _Tp>
+    minmax(initializer_list<_Tp> __l)
+    {
+      __glibcxx_requires_irreflexive(__l.begin(), __l.end());
+      pair<const _Tp*, const _Tp*> __p =
+	std::__minmax_element(__l.begin(), __l.end(),
+			      __gnu_cxx::__ops::__iter_less_iter());
+      return std::make_pair(*__p.first, *__p.second);
+    }
+
+  template<typename _Tp, typename _Compare>
+    _GLIBCXX14_CONSTEXPR
+    inline pair<_Tp, _Tp>
+    minmax(initializer_list<_Tp> __l, _Compare __comp)
+    {
+      __glibcxx_requires_irreflexive_pred(__l.begin(), __l.end(), __comp);
+      pair<const _Tp*, const _Tp*> __p =
+	std::__minmax_element(__l.begin(), __l.end(),
+			      __gnu_cxx::__ops::__iter_comp_iter(__comp));
+      return std::make_pair(*__p.first, *__p.second);
+    }
+
+  /**
+   *  @brief  Checks whether a permutation of the second sequence is equal
+   *          to the first sequence.
+   *  @ingroup non_mutating_algorithms
+   *  @param  __first1  Start of first range.
+   *  @param  __last1   End of first range.
+   *  @param  __first2  Start of second range.
+   *  @param  __pred    A binary predicate.
+   *  @return true if there exists a permutation of the elements in
+   *          the range [__first2, __first2 + (__last1 - __first1)),
+   *          beginning with ForwardIterator2 begin, such that
+   *          equal(__first1, __last1, __begin, __pred) returns true;
+   *          otherwise, returns false.
+  */
+  template<typename _ForwardIterator1, typename _ForwardIterator2,
+	   typename _BinaryPredicate>
+    _GLIBCXX20_CONSTEXPR
+    inline bool
+    is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
+		   _ForwardIterator2 __first2, _BinaryPredicate __pred)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator1>)
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator2>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,
+	    typename iterator_traits<_ForwardIterator1>::value_type,
+	    typename iterator_traits<_ForwardIterator2>::value_type>)
+      __glibcxx_requires_valid_range(__first1, __last1);
+
+      return std::__is_permutation(__first1, __last1, __first2,
+				   __gnu_cxx::__ops::__iter_comp_iter(__pred));
+    }
+
+#if __cplusplus > 201103L
+  template<typename _ForwardIterator1, typename _ForwardIterator2,
+	   typename _BinaryPredicate>
+    _GLIBCXX20_CONSTEXPR
+    bool
+    __is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
+		     _ForwardIterator2 __first2, _ForwardIterator2 __last2,
+		     _BinaryPredicate __pred)
+    {
+      using _Cat1
+	= typename iterator_traits<_ForwardIterator1>::iterator_category;
+      using _Cat2
+	= typename iterator_traits<_ForwardIterator2>::iterator_category;
+      using _It1_is_RA = is_same<_Cat1, random_access_iterator_tag>;
+      using _It2_is_RA = is_same<_Cat2, random_access_iterator_tag>;
+      constexpr bool __ra_iters = _It1_is_RA() && _It2_is_RA();
+      if (__ra_iters)
+	{
+	  auto __d1 = std::distance(__first1, __last1);
+	  auto __d2 = std::distance(__first2, __last2);
+	  if (__d1 != __d2)
+	    return false;
+	}
+
+      // Efficiently compare identical prefixes:  O(N) if sequences
+      // have the same elements in the same order.
+      for (; __first1 != __last1 && __first2 != __last2;
+	  ++__first1, (void)++__first2)
+	if (!__pred(__first1, __first2))
+	  break;
+
+      if (__ra_iters)
+	{
+	  if (__first1 == __last1)
+	    return true;
+	}
+      else
+	{
+	  auto __d1 = std::distance(__first1, __last1);
+	  auto __d2 = std::distance(__first2, __last2);
+	  if (__d1 == 0 && __d2 == 0)
+	    return true;
+	  if (__d1 != __d2)
+	    return false;
+	}
+
+      for (_ForwardIterator1 __scan = __first1; __scan != __last1; ++__scan)
+	{
+	  if (__scan != std::__find_if(__first1, __scan,
+			__gnu_cxx::__ops::__iter_comp_iter(__pred, __scan)))
+	    continue; // We've seen this one before.
+
+	  auto __matches = std::__count_if(__first2, __last2,
+		__gnu_cxx::__ops::__iter_comp_iter(__pred, __scan));
+	  if (0 == __matches
+	      || std::__count_if(__scan, __last1,
+			__gnu_cxx::__ops::__iter_comp_iter(__pred, __scan))
+	      != __matches)
+	    return false;
+	}
+      return true;
+    }
+
+  /**
+   *  @brief  Checks whether a permutaion of the second sequence is equal
+   *          to the first sequence.
+   *  @ingroup non_mutating_algorithms
+   *  @param  __first1  Start of first range.
+   *  @param  __last1   End of first range.
+   *  @param  __first2  Start of second range.
+   *  @param  __last2   End of first range.
+   *  @return true if there exists a permutation of the elements in the range
+   *          [__first2, __last2), beginning with ForwardIterator2 begin,
+   *          such that equal(__first1, __last1, begin) returns true;
+   *          otherwise, returns false.
+  */
+  template<typename _ForwardIterator1, typename _ForwardIterator2>
+    _GLIBCXX20_CONSTEXPR
+    inline bool
+    is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
+		   _ForwardIterator2 __first2, _ForwardIterator2 __last2)
+    {
+      __glibcxx_requires_valid_range(__first1, __last1);
+      __glibcxx_requires_valid_range(__first2, __last2);
+
+      return
+	std::__is_permutation(__first1, __last1, __first2, __last2,
+			      __gnu_cxx::__ops::__iter_equal_to_iter());
+    }
+
+  /**
+   *  @brief  Checks whether a permutation of the second sequence is equal
+   *          to the first sequence.
+   *  @ingroup non_mutating_algorithms
+   *  @param  __first1  Start of first range.
+   *  @param  __last1   End of first range.
+   *  @param  __first2  Start of second range.
+   *  @param  __last2   End of first range.
+   *  @param  __pred    A binary predicate.
+   *  @return true if there exists a permutation of the elements in the range
+   *          [__first2, __last2), beginning with ForwardIterator2 begin,
+   *          such that equal(__first1, __last1, __begin, __pred) returns true;
+   *          otherwise, returns false.
+  */
+  template<typename _ForwardIterator1, typename _ForwardIterator2,
+	   typename _BinaryPredicate>
+    _GLIBCXX20_CONSTEXPR
+    inline bool
+    is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
+		   _ForwardIterator2 __first2, _ForwardIterator2 __last2,
+		   _BinaryPredicate __pred)
+    {
+      __glibcxx_requires_valid_range(__first1, __last1);
+      __glibcxx_requires_valid_range(__first2, __last2);
+
+      return std::__is_permutation(__first1, __last1, __first2, __last2,
+				   __gnu_cxx::__ops::__iter_comp_iter(__pred));
+    }
+
+#if __cplusplus >= 201703L
+
+#define __cpp_lib_clamp 201603L
+
+  /**
+   *  @brief  Returns the value clamped between lo and hi.
+   *  @ingroup sorting_algorithms
+   *  @param  __val  A value of arbitrary type.
+   *  @param  __lo   A lower limit of arbitrary type.
+   *  @param  __hi   An upper limit of arbitrary type.
+   *  @retval `__lo` if `__val < __lo`
+   *  @retval `__hi` if `__hi < __val`
+   *  @retval `__val` otherwise.
+   *  @pre `_Tp` is LessThanComparable and `(__hi < __lo)` is false.
+   */
+  template<typename _Tp>
+    constexpr const _Tp&
+    clamp(const _Tp& __val, const _Tp& __lo, const _Tp& __hi)
+    {
+      __glibcxx_assert(!(__hi < __lo));
+      return std::min(std::max(__val, __lo), __hi);
+    }
+
+  /**
+   *  @brief  Returns the value clamped between lo and hi.
+   *  @ingroup sorting_algorithms
+   *  @param  __val   A value of arbitrary type.
+   *  @param  __lo    A lower limit of arbitrary type.
+   *  @param  __hi    An upper limit of arbitrary type.
+   *  @param  __comp  A comparison functor.
+   *  @retval `__lo` if `__comp(__val, __lo)`
+   *  @retval `__hi` if `__comp(__hi, __val)`
+   *  @retval `__val` otherwise.
+   *  @pre `__comp(__hi, __lo)` is false.
+   */
+  template<typename _Tp, typename _Compare>
+    constexpr const _Tp&
+    clamp(const _Tp& __val, const _Tp& __lo, const _Tp& __hi, _Compare __comp)
+    {
+      __glibcxx_assert(!__comp(__hi, __lo));
+      return std::min(std::max(__val, __lo, __comp), __hi, __comp);
+    }
+#endif // C++17
+#endif // C++14
+
+#ifdef _GLIBCXX_USE_C99_STDINT_TR1
+  /**
+   *  @brief Generate two uniformly distributed integers using a
+   *         single distribution invocation.
+   *  @param  __b0    The upper bound for the first integer.
+   *  @param  __b1    The upper bound for the second integer.
+   *  @param  __g     A UniformRandomBitGenerator.
+   *  @return  A pair (i, j) with i and j uniformly distributed
+   *           over [0, __b0) and [0, __b1), respectively.
+   *
+   *  Requires: __b0 * __b1 <= __g.max() - __g.min().
+   *
+   *  Using uniform_int_distribution with a range that is very
+   *  small relative to the range of the generator ends up wasting
+   *  potentially expensively generated randomness, since
+   *  uniform_int_distribution does not store leftover randomness
+   *  between invocations.
+   *
+   *  If we know we want two integers in ranges that are sufficiently
+   *  small, we can compose the ranges, use a single distribution
+   *  invocation, and significantly reduce the waste.
+  */
+  template<typename _IntType, typename _UniformRandomBitGenerator>
+    pair<_IntType, _IntType>
+    __gen_two_uniform_ints(_IntType __b0, _IntType __b1,
+			   _UniformRandomBitGenerator&& __g)
+    {
+      _IntType __x
+	= uniform_int_distribution<_IntType>{0, (__b0 * __b1) - 1}(__g);
+      return std::make_pair(__x / __b1, __x % __b1);
+    }
+
+  /**
+   *  @brief Shuffle the elements of a sequence using a uniform random
+   *         number generator.
+   *  @ingroup mutating_algorithms
+   *  @param  __first   A forward iterator.
+   *  @param  __last    A forward iterator.
+   *  @param  __g       A UniformRandomNumberGenerator (26.5.1.3).
+   *  @return  Nothing.
+   *
+   *  Reorders the elements in the range @p [__first,__last) using @p __g to
+   *  provide random numbers.
+  */
+  template<typename _RandomAccessIterator,
+	   typename _UniformRandomNumberGenerator>
+    void
+    shuffle(_RandomAccessIterator __first, _RandomAccessIterator __last,
+	    _UniformRandomNumberGenerator&& __g)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
+	    _RandomAccessIterator>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      if (__first == __last)
+	return;
+
+      typedef typename iterator_traits<_RandomAccessIterator>::difference_type
+	_DistanceType;
+
+      typedef typename std::make_unsigned<_DistanceType>::type __ud_type;
+      typedef typename std::uniform_int_distribution<__ud_type> __distr_type;
+      typedef typename __distr_type::param_type __p_type;
+
+      typedef typename remove_reference<_UniformRandomNumberGenerator>::type
+	_Gen;
+      typedef typename common_type<typename _Gen::result_type, __ud_type>::type
+	__uc_type;
+
+      const __uc_type __urngrange = __g.max() - __g.min();
+      const __uc_type __urange = __uc_type(__last - __first);
+
+      if (__urngrange / __urange >= __urange)
+        // I.e. (__urngrange >= __urange * __urange) but without wrap issues.
+      {
+	_RandomAccessIterator __i = __first + 1;
+
+	// Since we know the range isn't empty, an even number of elements
+	// means an uneven number of elements /to swap/, in which case we
+	// do the first one up front:
+
+	if ((__urange % 2) == 0)
+	{
+	  __distr_type __d{0, 1};
+	  std::iter_swap(__i++, __first + __d(__g));
+	}
+
+	// Now we know that __last - __i is even, so we do the rest in pairs,
+	// using a single distribution invocation to produce swap positions
+	// for two successive elements at a time:
+
+	while (__i != __last)
+	{
+	  const __uc_type __swap_range = __uc_type(__i - __first) + 1;
+
+	  const pair<__uc_type, __uc_type> __pospos =
+	    __gen_two_uniform_ints(__swap_range, __swap_range + 1, __g);
+
+	  std::iter_swap(__i++, __first + __pospos.first);
+	  std::iter_swap(__i++, __first + __pospos.second);
+	}
+
+	return;
+      }
+
+      __distr_type __d;
+
+      for (_RandomAccessIterator __i = __first + 1; __i != __last; ++__i)
+	std::iter_swap(__i, __first + __d(__g, __p_type(0, __i - __first)));
+    }
+#endif // USE C99_STDINT
+
+#endif // C++11
+
+_GLIBCXX_BEGIN_NAMESPACE_ALGO
+
+  /**
+   *  @brief Apply a function to every element of a sequence.
+   *  @ingroup non_mutating_algorithms
+   *  @param  __first  An input iterator.
+   *  @param  __last   An input iterator.
+   *  @param  __f      A unary function object.
+   *  @return   @p __f
+   *
+   *  Applies the function object @p __f to each element in the range
+   *  @p [first,last).  @p __f must not modify the order of the sequence.
+   *  If @p __f has a return value it is ignored.
+  */
+  template<typename _InputIterator, typename _Function>
+    _GLIBCXX20_CONSTEXPR
+    _Function
+    for_each(_InputIterator __first, _InputIterator __last, _Function __f)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
+      __glibcxx_requires_valid_range(__first, __last);
+      for (; __first != __last; ++__first)
+	__f(*__first);
+      return __f; // N.B. [alg.foreach] says std::move(f) but it's redundant.
+    }
+
+#if __cplusplus >= 201703L
+  /**
+   *  @brief Apply a function to every element of a sequence.
+   *  @ingroup non_mutating_algorithms
+   *  @param  __first  An input iterator.
+   *  @param  __n      A value convertible to an integer.
+   *  @param  __f      A unary function object.
+   *  @return   `__first+__n`
+   *
+   *  Applies the function object `__f` to each element in the range
+   *  `[first, first+n)`.  `__f` must not modify the order of the sequence.
+   *  If `__f` has a return value it is ignored.
+  */
+  template<typename _InputIterator, typename _Size, typename _Function>
+    _GLIBCXX20_CONSTEXPR
+    _InputIterator
+    for_each_n(_InputIterator __first, _Size __n, _Function __f)
+    {
+      auto __n2 = std::__size_to_integer(__n);
+      using _Cat = typename iterator_traits<_InputIterator>::iterator_category;
+      if constexpr (is_base_of_v<random_access_iterator_tag, _Cat>)
+	{
+	  if (__n2 <= 0)
+	    return __first;
+	  auto __last = __first + __n2;
+	  std::for_each(__first, __last, std::move(__f));
+	  return __last;
+	}
+      else
+	{
+	  while (__n2-->0)
+	    {
+	      __f(*__first);
+	      ++__first;
+	    }
+	  return __first;
+	}
+    }
+#endif // C++17
+
+  /**
+   *  @brief Find the first occurrence of a value in a sequence.
+   *  @ingroup non_mutating_algorithms
+   *  @param  __first  An input iterator.
+   *  @param  __last   An input iterator.
+   *  @param  __val    The value to find.
+   *  @return   The first iterator @c i in the range @p [__first,__last)
+   *  such that @c *i == @p __val, or @p __last if no such iterator exists.
+  */
+  template<typename _InputIterator, typename _Tp>
+    _GLIBCXX20_CONSTEXPR
+    inline _InputIterator
+    find(_InputIterator __first, _InputIterator __last,
+	 const _Tp& __val)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
+      __glibcxx_function_requires(_EqualOpConcept<
+		typename iterator_traits<_InputIterator>::value_type, _Tp>)
+      __glibcxx_requires_valid_range(__first, __last);
+      return std::__find_if(__first, __last,
+			    __gnu_cxx::__ops::__iter_equals_val(__val));
+    }
+
+  /**
+   *  @brief Find the first element in a sequence for which a
+   *         predicate is true.
+   *  @ingroup non_mutating_algorithms
+   *  @param  __first  An input iterator.
+   *  @param  __last   An input iterator.
+   *  @param  __pred   A predicate.
+   *  @return   The first iterator @c i in the range @p [__first,__last)
+   *  such that @p __pred(*i) is true, or @p __last if no such iterator exists.
+  */
+  template<typename _InputIterator, typename _Predicate>
+    _GLIBCXX20_CONSTEXPR
+    inline _InputIterator
+    find_if(_InputIterator __first, _InputIterator __last,
+	    _Predicate __pred)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
+      __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,
+	      typename iterator_traits<_InputIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      return std::__find_if(__first, __last,
+			    __gnu_cxx::__ops::__pred_iter(__pred));
+    }
+
+  /**
+   *  @brief  Find element from a set in a sequence.
+   *  @ingroup non_mutating_algorithms
+   *  @param  __first1  Start of range to search.
+   *  @param  __last1   End of range to search.
+   *  @param  __first2  Start of match candidates.
+   *  @param  __last2   End of match candidates.
+   *  @return   The first iterator @c i in the range
+   *  @p [__first1,__last1) such that @c *i == @p *(i2) such that i2 is an
+   *  iterator in [__first2,__last2), or @p __last1 if no such iterator exists.
+   *
+   *  Searches the range @p [__first1,__last1) for an element that is
+   *  equal to some element in the range [__first2,__last2).  If
+   *  found, returns an iterator in the range [__first1,__last1),
+   *  otherwise returns @p __last1.
+  */
+  template<typename _InputIterator, typename _ForwardIterator>
+    _GLIBCXX20_CONSTEXPR
+    _InputIterator
+    find_first_of(_InputIterator __first1, _InputIterator __last1,
+		  _ForwardIterator __first2, _ForwardIterator __last2)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+      __glibcxx_function_requires(_EqualOpConcept<
+	    typename iterator_traits<_InputIterator>::value_type,
+	    typename iterator_traits<_ForwardIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first1, __last1);
+      __glibcxx_requires_valid_range(__first2, __last2);
+
+      for (; __first1 != __last1; ++__first1)
+	for (_ForwardIterator __iter = __first2; __iter != __last2; ++__iter)
+	  if (*__first1 == *__iter)
+	    return __first1;
+      return __last1;
+    }
+
+  /**
+   *  @brief  Find element from a set in a sequence using a predicate.
+   *  @ingroup non_mutating_algorithms
+   *  @param  __first1  Start of range to search.
+   *  @param  __last1   End of range to search.
+   *  @param  __first2  Start of match candidates.
+   *  @param  __last2   End of match candidates.
+   *  @param  __comp    Predicate to use.
+   *  @return   The first iterator @c i in the range
+   *  @p [__first1,__last1) such that @c comp(*i, @p *(i2)) is true
+   *  and i2 is an iterator in [__first2,__last2), or @p __last1 if no
+   *  such iterator exists.
+   *
+
+   *  Searches the range @p [__first1,__last1) for an element that is
+   *  equal to some element in the range [__first2,__last2).  If
+   *  found, returns an iterator in the range [__first1,__last1),
+   *  otherwise returns @p __last1.
+  */
+  template<typename _InputIterator, typename _ForwardIterator,
+	   typename _BinaryPredicate>
+    _GLIBCXX20_CONSTEXPR
+    _InputIterator
+    find_first_of(_InputIterator __first1, _InputIterator __last1,
+		  _ForwardIterator __first2, _ForwardIterator __last2,
+		  _BinaryPredicate __comp)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,
+	    typename iterator_traits<_InputIterator>::value_type,
+	    typename iterator_traits<_ForwardIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first1, __last1);
+      __glibcxx_requires_valid_range(__first2, __last2);
+
+      for (; __first1 != __last1; ++__first1)
+	for (_ForwardIterator __iter = __first2; __iter != __last2; ++__iter)
+	  if (__comp(*__first1, *__iter))
+	    return __first1;
+      return __last1;
+    }
+
+  /**
+   *  @brief Find two adjacent values in a sequence that are equal.
+   *  @ingroup non_mutating_algorithms
+   *  @param  __first  A forward iterator.
+   *  @param  __last   A forward iterator.
+   *  @return   The first iterator @c i such that @c i and @c i+1 are both
+   *  valid iterators in @p [__first,__last) and such that @c *i == @c *(i+1),
+   *  or @p __last if no such iterator exists.
+  */
+  template<typename _ForwardIterator>
+    _GLIBCXX20_CONSTEXPR
+    inline _ForwardIterator
+    adjacent_find(_ForwardIterator __first, _ForwardIterator __last)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+      __glibcxx_function_requires(_EqualityComparableConcept<
+	    typename iterator_traits<_ForwardIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      return std::__adjacent_find(__first, __last,
+				  __gnu_cxx::__ops::__iter_equal_to_iter());
+    }
+
+  /**
+   *  @brief Find two adjacent values in a sequence using a predicate.
+   *  @ingroup non_mutating_algorithms
+   *  @param  __first         A forward iterator.
+   *  @param  __last          A forward iterator.
+   *  @param  __binary_pred   A binary predicate.
+   *  @return   The first iterator @c i such that @c i and @c i+1 are both
+   *  valid iterators in @p [__first,__last) and such that
+   *  @p __binary_pred(*i,*(i+1)) is true, or @p __last if no such iterator
+   *  exists.
+  */
+  template<typename _ForwardIterator, typename _BinaryPredicate>
+    _GLIBCXX20_CONSTEXPR
+    inline _ForwardIterator
+    adjacent_find(_ForwardIterator __first, _ForwardIterator __last,
+		  _BinaryPredicate __binary_pred)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,
+	    typename iterator_traits<_ForwardIterator>::value_type,
+	    typename iterator_traits<_ForwardIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      return std::__adjacent_find(__first, __last,
+			__gnu_cxx::__ops::__iter_comp_iter(__binary_pred));
+    }
+
+  /**
+   *  @brief Count the number of copies of a value in a sequence.
+   *  @ingroup non_mutating_algorithms
+   *  @param  __first  An input iterator.
+   *  @param  __last   An input iterator.
+   *  @param  __value  The value to be counted.
+   *  @return   The number of iterators @c i in the range @p [__first,__last)
+   *  for which @c *i == @p __value
+  */
+  template<typename _InputIterator, typename _Tp>
+    _GLIBCXX20_CONSTEXPR
+    inline typename iterator_traits<_InputIterator>::difference_type
+    count(_InputIterator __first, _InputIterator __last, const _Tp& __value)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
+      __glibcxx_function_requires(_EqualOpConcept<
+	    typename iterator_traits<_InputIterator>::value_type, _Tp>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      return std::__count_if(__first, __last,
+			     __gnu_cxx::__ops::__iter_equals_val(__value));
+    }
+
+  /**
+   *  @brief Count the elements of a sequence for which a predicate is true.
+   *  @ingroup non_mutating_algorithms
+   *  @param  __first  An input iterator.
+   *  @param  __last   An input iterator.
+   *  @param  __pred   A predicate.
+   *  @return   The number of iterators @c i in the range @p [__first,__last)
+   *  for which @p __pred(*i) is true.
+  */
+  template<typename _InputIterator, typename _Predicate>
+    _GLIBCXX20_CONSTEXPR
+    inline typename iterator_traits<_InputIterator>::difference_type
+    count_if(_InputIterator __first, _InputIterator __last, _Predicate __pred)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
+      __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,
+	    typename iterator_traits<_InputIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      return std::__count_if(__first, __last,
+			     __gnu_cxx::__ops::__pred_iter(__pred));
+    }
+
+  /**
+   *  @brief Search a sequence for a matching sub-sequence.
+   *  @ingroup non_mutating_algorithms
+   *  @param  __first1  A forward iterator.
+   *  @param  __last1   A forward iterator.
+   *  @param  __first2  A forward iterator.
+   *  @param  __last2   A forward iterator.
+   *  @return The first iterator @c i in the range @p
+   *  [__first1,__last1-(__last2-__first2)) such that @c *(i+N) == @p
+   *  *(__first2+N) for each @c N in the range @p
+   *  [0,__last2-__first2), or @p __last1 if no such iterator exists.
+   *
+   *  Searches the range @p [__first1,__last1) for a sub-sequence that
+   *  compares equal value-by-value with the sequence given by @p
+   *  [__first2,__last2) and returns an iterator to the first element
+   *  of the sub-sequence, or @p __last1 if the sub-sequence is not
+   *  found.
+   *
+   *  Because the sub-sequence must lie completely within the range @p
+   *  [__first1,__last1) it must start at a position less than @p
+   *  __last1-(__last2-__first2) where @p __last2-__first2 is the
+   *  length of the sub-sequence.
+   *
+   *  This means that the returned iterator @c i will be in the range
+   *  @p [__first1,__last1-(__last2-__first2))
+  */
+  template<typename _ForwardIterator1, typename _ForwardIterator2>
+    _GLIBCXX20_CONSTEXPR
+    inline _ForwardIterator1
+    search(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
+	   _ForwardIterator2 __first2, _ForwardIterator2 __last2)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator1>)
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator2>)
+      __glibcxx_function_requires(_EqualOpConcept<
+	    typename iterator_traits<_ForwardIterator1>::value_type,
+	    typename iterator_traits<_ForwardIterator2>::value_type>)
+      __glibcxx_requires_valid_range(__first1, __last1);
+      __glibcxx_requires_valid_range(__first2, __last2);
+
+      return std::__search(__first1, __last1, __first2, __last2,
+			   __gnu_cxx::__ops::__iter_equal_to_iter());
+    }
+
+  /**
+   *  @brief Search a sequence for a matching sub-sequence using a predicate.
+   *  @ingroup non_mutating_algorithms
+   *  @param  __first1     A forward iterator.
+   *  @param  __last1      A forward iterator.
+   *  @param  __first2     A forward iterator.
+   *  @param  __last2      A forward iterator.
+   *  @param  __predicate  A binary predicate.
+   *  @return   The first iterator @c i in the range
+   *  @p [__first1,__last1-(__last2-__first2)) such that
+   *  @p __predicate(*(i+N),*(__first2+N)) is true for each @c N in the range
+   *  @p [0,__last2-__first2), or @p __last1 if no such iterator exists.
+   *
+   *  Searches the range @p [__first1,__last1) for a sub-sequence that
+   *  compares equal value-by-value with the sequence given by @p
+   *  [__first2,__last2), using @p __predicate to determine equality,
+   *  and returns an iterator to the first element of the
+   *  sub-sequence, or @p __last1 if no such iterator exists.
+   *
+   *  @see search(_ForwardIter1, _ForwardIter1, _ForwardIter2, _ForwardIter2)
+  */
+  template<typename _ForwardIterator1, typename _ForwardIterator2,
+	   typename _BinaryPredicate>
+    _GLIBCXX20_CONSTEXPR
+    inline _ForwardIterator1
+    search(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
+	   _ForwardIterator2 __first2, _ForwardIterator2 __last2,
+	   _BinaryPredicate  __predicate)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator1>)
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator2>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,
+	    typename iterator_traits<_ForwardIterator1>::value_type,
+	    typename iterator_traits<_ForwardIterator2>::value_type>)
+      __glibcxx_requires_valid_range(__first1, __last1);
+      __glibcxx_requires_valid_range(__first2, __last2);
+
+      return std::__search(__first1, __last1, __first2, __last2,
+			   __gnu_cxx::__ops::__iter_comp_iter(__predicate));
+    }
+
+  /**
+   *  @brief Search a sequence for a number of consecutive values.
+   *  @ingroup non_mutating_algorithms
+   *  @param  __first  A forward iterator.
+   *  @param  __last   A forward iterator.
+   *  @param  __count  The number of consecutive values.
+   *  @param  __val    The value to find.
+   *  @return The first iterator @c i in the range @p
+   *  [__first,__last-__count) such that @c *(i+N) == @p __val for
+   *  each @c N in the range @p [0,__count), or @p __last if no such
+   *  iterator exists.
+   *
+   *  Searches the range @p [__first,__last) for @p count consecutive elements
+   *  equal to @p __val.
+  */
+  template<typename _ForwardIterator, typename _Integer, typename _Tp>
+    _GLIBCXX20_CONSTEXPR
+    inline _ForwardIterator
+    search_n(_ForwardIterator __first, _ForwardIterator __last,
+	     _Integer __count, const _Tp& __val)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+      __glibcxx_function_requires(_EqualOpConcept<
+	    typename iterator_traits<_ForwardIterator>::value_type, _Tp>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      return std::__search_n(__first, __last, __count,
+			     __gnu_cxx::__ops::__iter_equals_val(__val));
+    }
+
+
+  /**
+   *  @brief Search a sequence for a number of consecutive values using a
+   *         predicate.
+   *  @ingroup non_mutating_algorithms
+   *  @param  __first        A forward iterator.
+   *  @param  __last         A forward iterator.
+   *  @param  __count        The number of consecutive values.
+   *  @param  __val          The value to find.
+   *  @param  __binary_pred  A binary predicate.
+   *  @return The first iterator @c i in the range @p
+   *  [__first,__last-__count) such that @p
+   *  __binary_pred(*(i+N),__val) is true for each @c N in the range
+   *  @p [0,__count), or @p __last if no such iterator exists.
+   *
+   *  Searches the range @p [__first,__last) for @p __count
+   *  consecutive elements for which the predicate returns true.
+  */
+  template<typename _ForwardIterator, typename _Integer, typename _Tp,
+	   typename _BinaryPredicate>
+    _GLIBCXX20_CONSTEXPR
+    inline _ForwardIterator
+    search_n(_ForwardIterator __first, _ForwardIterator __last,
+	     _Integer __count, const _Tp& __val,
+	     _BinaryPredicate __binary_pred)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,
+	    typename iterator_traits<_ForwardIterator>::value_type, _Tp>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      return std::__search_n(__first, __last, __count,
+		__gnu_cxx::__ops::__iter_comp_val(__binary_pred, __val));
+    }
+
+#if __cplusplus >= 201703L
+  /** @brief Search a sequence using a Searcher object.
+   *
+   *  @param  __first        A forward iterator.
+   *  @param  __last         A forward iterator.
+   *  @param  __searcher     A callable object.
+   *  @return @p __searcher(__first,__last).first
+  */
+  template<typename _ForwardIterator, typename _Searcher>
+    _GLIBCXX20_CONSTEXPR
+    inline _ForwardIterator
+    search(_ForwardIterator __first, _ForwardIterator __last,
+	   const _Searcher& __searcher)
+    { return __searcher(__first, __last).first; }
+#endif
+
+  /**
+   *  @brief Perform an operation on a sequence.
+   *  @ingroup mutating_algorithms
+   *  @param  __first     An input iterator.
+   *  @param  __last      An input iterator.
+   *  @param  __result    An output iterator.
+   *  @param  __unary_op  A unary operator.
+   *  @return   An output iterator equal to @p __result+(__last-__first).
+   *
+   *  Applies the operator to each element in the input range and assigns
+   *  the results to successive elements of the output sequence.
+   *  Evaluates @p *(__result+N)=unary_op(*(__first+N)) for each @c N in the
+   *  range @p [0,__last-__first).
+   *
+   *  @p unary_op must not alter its argument.
+  */
+  template<typename _InputIterator, typename _OutputIterator,
+	   typename _UnaryOperation>
+    _GLIBCXX20_CONSTEXPR
+    _OutputIterator
+    transform(_InputIterator __first, _InputIterator __last,
+	      _OutputIterator __result, _UnaryOperation __unary_op)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
+	    // "the type returned by a _UnaryOperation"
+	    __typeof__(__unary_op(*__first))>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      for (; __first != __last; ++__first, (void)++__result)
+	*__result = __unary_op(*__first);
+      return __result;
+    }
+
+  /**
+   *  @brief Perform an operation on corresponding elements of two sequences.
+   *  @ingroup mutating_algorithms
+   *  @param  __first1     An input iterator.
+   *  @param  __last1      An input iterator.
+   *  @param  __first2     An input iterator.
+   *  @param  __result     An output iterator.
+   *  @param  __binary_op  A binary operator.
+   *  @return   An output iterator equal to @p result+(last-first).
+   *
+   *  Applies the operator to the corresponding elements in the two
+   *  input ranges and assigns the results to successive elements of the
+   *  output sequence.
+   *  Evaluates @p
+   *  *(__result+N)=__binary_op(*(__first1+N),*(__first2+N)) for each
+   *  @c N in the range @p [0,__last1-__first1).
+   *
+   *  @p binary_op must not alter either of its arguments.
+  */
+  template<typename _InputIterator1, typename _InputIterator2,
+	   typename _OutputIterator, typename _BinaryOperation>
+    _GLIBCXX20_CONSTEXPR
+    _OutputIterator
+    transform(_InputIterator1 __first1, _InputIterator1 __last1,
+	      _InputIterator2 __first2, _OutputIterator __result,
+	      _BinaryOperation __binary_op)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
+	    // "the type returned by a _BinaryOperation"
+	    __typeof__(__binary_op(*__first1,*__first2))>)
+      __glibcxx_requires_valid_range(__first1, __last1);
+
+      for (; __first1 != __last1; ++__first1, (void)++__first2, ++__result)
+	*__result = __binary_op(*__first1, *__first2);
+      return __result;
+    }
+
+  /**
+   *  @brief Replace each occurrence of one value in a sequence with another
+   *         value.
+   *  @ingroup mutating_algorithms
+   *  @param  __first      A forward iterator.
+   *  @param  __last       A forward iterator.
+   *  @param  __old_value  The value to be replaced.
+   *  @param  __new_value  The replacement value.
+   *  @return   replace() returns no value.
+   *
+   *  For each iterator @c i in the range @p [__first,__last) if @c *i ==
+   *  @p __old_value then the assignment @c *i = @p __new_value is performed.
+  */
+  template<typename _ForwardIterator, typename _Tp>
+    _GLIBCXX20_CONSTEXPR
+    void
+    replace(_ForwardIterator __first, _ForwardIterator __last,
+	    const _Tp& __old_value, const _Tp& __new_value)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
+				  _ForwardIterator>)
+      __glibcxx_function_requires(_EqualOpConcept<
+	    typename iterator_traits<_ForwardIterator>::value_type, _Tp>)
+      __glibcxx_function_requires(_ConvertibleConcept<_Tp,
+	    typename iterator_traits<_ForwardIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      for (; __first != __last; ++__first)
+	if (*__first == __old_value)
+	  *__first = __new_value;
+    }
+
+  /**
+   *  @brief Replace each value in a sequence for which a predicate returns
+   *         true with another value.
+   *  @ingroup mutating_algorithms
+   *  @param  __first      A forward iterator.
+   *  @param  __last       A forward iterator.
+   *  @param  __pred       A predicate.
+   *  @param  __new_value  The replacement value.
+   *  @return   replace_if() returns no value.
+   *
+   *  For each iterator @c i in the range @p [__first,__last) if @p __pred(*i)
+   *  is true then the assignment @c *i = @p __new_value is performed.
+  */
+  template<typename _ForwardIterator, typename _Predicate, typename _Tp>
+    _GLIBCXX20_CONSTEXPR
+    void
+    replace_if(_ForwardIterator __first, _ForwardIterator __last,
+	       _Predicate __pred, const _Tp& __new_value)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
+				  _ForwardIterator>)
+      __glibcxx_function_requires(_ConvertibleConcept<_Tp,
+	    typename iterator_traits<_ForwardIterator>::value_type>)
+      __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,
+	    typename iterator_traits<_ForwardIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      for (; __first != __last; ++__first)
+	if (__pred(*__first))
+	  *__first = __new_value;
+    }
+
+  /**
+   *  @brief Assign the result of a function object to each value in a
+   *         sequence.
+   *  @ingroup mutating_algorithms
+   *  @param  __first  A forward iterator.
+   *  @param  __last   A forward iterator.
+   *  @param  __gen    A function object taking no arguments and returning
+   *                 std::iterator_traits<_ForwardIterator>::value_type
+   *  @return   generate() returns no value.
+   *
+   *  Performs the assignment @c *i = @p __gen() for each @c i in the range
+   *  @p [__first,__last).
+  */
+  template<typename _ForwardIterator, typename _Generator>
+    _GLIBCXX20_CONSTEXPR
+    void
+    generate(_ForwardIterator __first, _ForwardIterator __last,
+	     _Generator __gen)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+      __glibcxx_function_requires(_GeneratorConcept<_Generator,
+	    typename iterator_traits<_ForwardIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      for (; __first != __last; ++__first)
+	*__first = __gen();
+    }
+
+  /**
+   *  @brief Assign the result of a function object to each value in a
+   *         sequence.
+   *  @ingroup mutating_algorithms
+   *  @param  __first  A forward iterator.
+   *  @param  __n      The length of the sequence.
+   *  @param  __gen    A function object taking no arguments and returning
+   *                 std::iterator_traits<_ForwardIterator>::value_type
+   *  @return   The end of the sequence, @p __first+__n
+   *
+   *  Performs the assignment @c *i = @p __gen() for each @c i in the range
+   *  @p [__first,__first+__n).
+   *
+   * If @p __n is negative, the function does nothing and returns @p __first.
+  */
+  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+  // DR 865. More algorithms that throw away information
+  // DR 426. search_n(), fill_n(), and generate_n() with negative n
+  template<typename _OutputIterator, typename _Size, typename _Generator>
+    _GLIBCXX20_CONSTEXPR
+    _OutputIterator
+    generate_n(_OutputIterator __first, _Size __n, _Generator __gen)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
+	    // "the type returned by a _Generator"
+	    __typeof__(__gen())>)
+
+      typedef __decltype(std::__size_to_integer(__n)) _IntSize;
+      for (_IntSize __niter = std::__size_to_integer(__n);
+	   __niter > 0; --__niter, (void) ++__first)
+	*__first = __gen();
+      return __first;
+    }
+
+  /**
+   *  @brief Copy a sequence, removing consecutive duplicate values.
+   *  @ingroup mutating_algorithms
+   *  @param  __first   An input iterator.
+   *  @param  __last    An input iterator.
+   *  @param  __result  An output iterator.
+   *  @return   An iterator designating the end of the resulting sequence.
+   *
+   *  Copies each element in the range @p [__first,__last) to the range
+   *  beginning at @p __result, except that only the first element is copied
+   *  from groups of consecutive elements that compare equal.
+   *  unique_copy() is stable, so the relative order of elements that are
+   *  copied is unchanged.
+   *
+   *  _GLIBCXX_RESOLVE_LIB_DEFECTS
+   *  DR 241. Does unique_copy() require CopyConstructible and Assignable?
+   *  
+   *  _GLIBCXX_RESOLVE_LIB_DEFECTS
+   *  DR 538. 241 again: Does unique_copy() require CopyConstructible and 
+   *  Assignable?
+  */
+  template<typename _InputIterator, typename _OutputIterator>
+    _GLIBCXX20_CONSTEXPR
+    inline _OutputIterator
+    unique_copy(_InputIterator __first, _InputIterator __last,
+		_OutputIterator __result)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
+	    typename iterator_traits<_InputIterator>::value_type>)
+      __glibcxx_function_requires(_EqualityComparableConcept<
+	    typename iterator_traits<_InputIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      if (__first == __last)
+	return __result;
+      return std::__unique_copy(__first, __last, __result,
+				__gnu_cxx::__ops::__iter_equal_to_iter(),
+				std::__iterator_category(__first),
+				std::__iterator_category(__result));
+    }
+
+  /**
+   *  @brief Copy a sequence, removing consecutive values using a predicate.
+   *  @ingroup mutating_algorithms
+   *  @param  __first        An input iterator.
+   *  @param  __last         An input iterator.
+   *  @param  __result       An output iterator.
+   *  @param  __binary_pred  A binary predicate.
+   *  @return   An iterator designating the end of the resulting sequence.
+   *
+   *  Copies each element in the range @p [__first,__last) to the range
+   *  beginning at @p __result, except that only the first element is copied
+   *  from groups of consecutive elements for which @p __binary_pred returns
+   *  true.
+   *  unique_copy() is stable, so the relative order of elements that are
+   *  copied is unchanged.
+   *
+   *  _GLIBCXX_RESOLVE_LIB_DEFECTS
+   *  DR 241. Does unique_copy() require CopyConstructible and Assignable?
+  */
+  template<typename _InputIterator, typename _OutputIterator,
+	   typename _BinaryPredicate>
+    _GLIBCXX20_CONSTEXPR
+    inline _OutputIterator
+    unique_copy(_InputIterator __first, _InputIterator __last,
+		_OutputIterator __result,
+		_BinaryPredicate __binary_pred)
+    {
+      // concept requirements -- predicates checked later
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
+	    typename iterator_traits<_InputIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      if (__first == __last)
+	return __result;
+      return std::__unique_copy(__first, __last, __result,
+			__gnu_cxx::__ops::__iter_comp_iter(__binary_pred),
+				std::__iterator_category(__first),
+				std::__iterator_category(__result));
+    }
+
+#if __cplusplus <= 201103L || _GLIBCXX_USE_DEPRECATED
+#if _GLIBCXX_HOSTED
+  /**
+   *  @brief Randomly shuffle the elements of a sequence.
+   *  @ingroup mutating_algorithms
+   *  @param  __first   A forward iterator.
+   *  @param  __last    A forward iterator.
+   *  @return  Nothing.
+   *
+   *  Reorder the elements in the range @p [__first,__last) using a random
+   *  distribution, so that every possible ordering of the sequence is
+   *  equally likely.
+   *
+   *  @deprecated
+   *  Since C++14 `std::random_shuffle` is not part of the C++ standard.
+   *  Use `std::shuffle` instead, which was introduced in C++11.
+  */
+  template<typename _RandomAccessIterator>
+    _GLIBCXX14_DEPRECATED_SUGGEST("std::shuffle")
+    inline void
+    random_shuffle(_RandomAccessIterator __first, _RandomAccessIterator __last)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
+	    _RandomAccessIterator>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      if (__first != __last)
+	for (_RandomAccessIterator __i = __first + 1; __i != __last; ++__i)
+	  {
+	    // XXX rand() % N is not uniformly distributed
+	    _RandomAccessIterator __j = __first
+					+ std::rand() % ((__i - __first) + 1);
+	    if (__i != __j)
+	      std::iter_swap(__i, __j);
+	  }
+    }
+#endif
+
+  /**
+   *  @brief Shuffle the elements of a sequence using a random number
+   *         generator.
+   *  @ingroup mutating_algorithms
+   *  @param  __first   A forward iterator.
+   *  @param  __last    A forward iterator.
+   *  @param  __rand    The RNG functor or function.
+   *  @return  Nothing.
+   *
+   *  Reorders the elements in the range @p [__first,__last) using @p __rand to
+   *  provide a random distribution. Calling @p __rand(N) for a positive
+   *  integer @p N should return a randomly chosen integer from the
+   *  range [0,N).
+   *
+   *  @deprecated
+   *  Since C++14 `std::random_shuffle` is not part of the C++ standard.
+   *  Use `std::shuffle` instead, which was introduced in C++11.
+  */
+  template<typename _RandomAccessIterator, typename _RandomNumberGenerator>
+    _GLIBCXX14_DEPRECATED_SUGGEST("std::shuffle")
+    void
+    random_shuffle(_RandomAccessIterator __first, _RandomAccessIterator __last,
+#if __cplusplus >= 201103L
+		   _RandomNumberGenerator&& __rand)
+#else
+		   _RandomNumberGenerator& __rand)
+#endif
+    {
+      // concept requirements
+      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
+	    _RandomAccessIterator>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      if (__first == __last)
+	return;
+      for (_RandomAccessIterator __i = __first + 1; __i != __last; ++__i)
+	{
+	  _RandomAccessIterator __j = __first + __rand((__i - __first) + 1);
+	  if (__i != __j)
+	    std::iter_swap(__i, __j);
+	}
+    }
+#endif // C++11 || USE_DEPRECATED
+
+  /**
+   *  @brief Move elements for which a predicate is true to the beginning
+   *         of a sequence.
+   *  @ingroup mutating_algorithms
+   *  @param  __first   A forward iterator.
+   *  @param  __last    A forward iterator.
+   *  @param  __pred    A predicate functor.
+   *  @return  An iterator @p middle such that @p __pred(i) is true for each
+   *  iterator @p i in the range @p [__first,middle) and false for each @p i
+   *  in the range @p [middle,__last).
+   *
+   *  @p __pred must not modify its operand. @p partition() does not preserve
+   *  the relative ordering of elements in each group, use
+   *  @p stable_partition() if this is needed.
+  */
+  template<typename _ForwardIterator, typename _Predicate>
+    _GLIBCXX20_CONSTEXPR
+    inline _ForwardIterator
+    partition(_ForwardIterator __first, _ForwardIterator __last,
+	      _Predicate   __pred)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
+				  _ForwardIterator>)
+      __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,
+	    typename iterator_traits<_ForwardIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      return std::__partition(__first, __last, __pred,
+			      std::__iterator_category(__first));
+    }
+
+
+  /**
+   *  @brief Sort the smallest elements of a sequence.
+   *  @ingroup sorting_algorithms
+   *  @param  __first   An iterator.
+   *  @param  __middle  Another iterator.
+   *  @param  __last    Another iterator.
+   *  @return  Nothing.
+   *
+   *  Sorts the smallest @p (__middle-__first) elements in the range
+   *  @p [first,last) and moves them to the range @p [__first,__middle). The
+   *  order of the remaining elements in the range @p [__middle,__last) is
+   *  undefined.
+   *  After the sort if @e i and @e j are iterators in the range
+   *  @p [__first,__middle) such that i precedes j and @e k is an iterator in
+   *  the range @p [__middle,__last) then *j<*i and *k<*i are both false.
+  */
+  template<typename _RandomAccessIterator>
+    _GLIBCXX20_CONSTEXPR
+    inline void
+    partial_sort(_RandomAccessIterator __first,
+		 _RandomAccessIterator __middle,
+		 _RandomAccessIterator __last)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
+	    _RandomAccessIterator>)
+      __glibcxx_function_requires(_LessThanComparableConcept<
+	    typename iterator_traits<_RandomAccessIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __middle);
+      __glibcxx_requires_valid_range(__middle, __last);
+      __glibcxx_requires_irreflexive(__first, __last);
+
+      std::__partial_sort(__first, __middle, __last,
+			  __gnu_cxx::__ops::__iter_less_iter());
+    }
+
+  /**
+   *  @brief Sort the smallest elements of a sequence using a predicate
+   *         for comparison.
+   *  @ingroup sorting_algorithms
+   *  @param  __first   An iterator.
+   *  @param  __middle  Another iterator.
+   *  @param  __last    Another iterator.
+   *  @param  __comp    A comparison functor.
+   *  @return  Nothing.
+   *
+   *  Sorts the smallest @p (__middle-__first) elements in the range
+   *  @p [__first,__last) and moves them to the range @p [__first,__middle). The
+   *  order of the remaining elements in the range @p [__middle,__last) is
+   *  undefined.
+   *  After the sort if @e i and @e j are iterators in the range
+   *  @p [__first,__middle) such that i precedes j and @e k is an iterator in
+   *  the range @p [__middle,__last) then @p *__comp(j,*i) and @p __comp(*k,*i)
+   *  are both false.
+  */
+  template<typename _RandomAccessIterator, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    inline void
+    partial_sort(_RandomAccessIterator __first,
+		 _RandomAccessIterator __middle,
+		 _RandomAccessIterator __last,
+		 _Compare __comp)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
+	    _RandomAccessIterator>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
+	    typename iterator_traits<_RandomAccessIterator>::value_type,
+	    typename iterator_traits<_RandomAccessIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __middle);
+      __glibcxx_requires_valid_range(__middle, __last);
+      __glibcxx_requires_irreflexive_pred(__first, __last, __comp);
+
+      std::__partial_sort(__first, __middle, __last,
+			  __gnu_cxx::__ops::__iter_comp_iter(__comp));
+    }
+
+  /**
+   *  @brief Sort a sequence just enough to find a particular position.
+   *  @ingroup sorting_algorithms
+   *  @param  __first   An iterator.
+   *  @param  __nth     Another iterator.
+   *  @param  __last    Another iterator.
+   *  @return  Nothing.
+   *
+   *  Rearranges the elements in the range @p [__first,__last) so that @p *__nth
+   *  is the same element that would have been in that position had the
+   *  whole sequence been sorted. The elements either side of @p *__nth are
+   *  not completely sorted, but for any iterator @e i in the range
+   *  @p [__first,__nth) and any iterator @e j in the range @p [__nth,__last) it
+   *  holds that *j < *i is false.
+  */
+  template<typename _RandomAccessIterator>
+    _GLIBCXX20_CONSTEXPR
+    inline void
+    nth_element(_RandomAccessIterator __first, _RandomAccessIterator __nth,
+		_RandomAccessIterator __last)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
+				  _RandomAccessIterator>)
+      __glibcxx_function_requires(_LessThanComparableConcept<
+	    typename iterator_traits<_RandomAccessIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __nth);
+      __glibcxx_requires_valid_range(__nth, __last);
+      __glibcxx_requires_irreflexive(__first, __last);
+
+      if (__first == __last || __nth == __last)
+	return;
+
+      std::__introselect(__first, __nth, __last,
+			 std::__lg(__last - __first) * 2,
+			 __gnu_cxx::__ops::__iter_less_iter());
+    }
+
+  /**
+   *  @brief Sort a sequence just enough to find a particular position
+   *         using a predicate for comparison.
+   *  @ingroup sorting_algorithms
+   *  @param  __first   An iterator.
+   *  @param  __nth     Another iterator.
+   *  @param  __last    Another iterator.
+   *  @param  __comp    A comparison functor.
+   *  @return  Nothing.
+   *
+   *  Rearranges the elements in the range @p [__first,__last) so that @p *__nth
+   *  is the same element that would have been in that position had the
+   *  whole sequence been sorted. The elements either side of @p *__nth are
+   *  not completely sorted, but for any iterator @e i in the range
+   *  @p [__first,__nth) and any iterator @e j in the range @p [__nth,__last) it
+   *  holds that @p __comp(*j,*i) is false.
+  */
+  template<typename _RandomAccessIterator, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    inline void
+    nth_element(_RandomAccessIterator __first, _RandomAccessIterator __nth,
+		_RandomAccessIterator __last, _Compare __comp)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
+				  _RandomAccessIterator>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
+	    typename iterator_traits<_RandomAccessIterator>::value_type,
+	    typename iterator_traits<_RandomAccessIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __nth);
+      __glibcxx_requires_valid_range(__nth, __last);
+      __glibcxx_requires_irreflexive_pred(__first, __last, __comp);
+
+      if (__first == __last || __nth == __last)
+	return;
+
+      std::__introselect(__first, __nth, __last,
+			 std::__lg(__last - __first) * 2,
+			 __gnu_cxx::__ops::__iter_comp_iter(__comp));
+    }
+
+  /**
+   *  @brief Sort the elements of a sequence.
+   *  @ingroup sorting_algorithms
+   *  @param  __first   An iterator.
+   *  @param  __last    Another iterator.
+   *  @return  Nothing.
+   *
+   *  Sorts the elements in the range @p [__first,__last) in ascending order,
+   *  such that for each iterator @e i in the range @p [__first,__last-1),  
+   *  *(i+1)<*i is false.
+   *
+   *  The relative ordering of equivalent elements is not preserved, use
+   *  @p stable_sort() if this is needed.
+  */
+  template<typename _RandomAccessIterator>
+    _GLIBCXX20_CONSTEXPR
+    inline void
+    sort(_RandomAccessIterator __first, _RandomAccessIterator __last)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
+	    _RandomAccessIterator>)
+      __glibcxx_function_requires(_LessThanComparableConcept<
+	    typename iterator_traits<_RandomAccessIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+      __glibcxx_requires_irreflexive(__first, __last);
+
+      std::__sort(__first, __last, __gnu_cxx::__ops::__iter_less_iter());
+    }
+
+  /**
+   *  @brief Sort the elements of a sequence using a predicate for comparison.
+   *  @ingroup sorting_algorithms
+   *  @param  __first   An iterator.
+   *  @param  __last    Another iterator.
+   *  @param  __comp    A comparison functor.
+   *  @return  Nothing.
+   *
+   *  Sorts the elements in the range @p [__first,__last) in ascending order,
+   *  such that @p __comp(*(i+1),*i) is false for every iterator @e i in the
+   *  range @p [__first,__last-1).
+   *
+   *  The relative ordering of equivalent elements is not preserved, use
+   *  @p stable_sort() if this is needed.
+  */
+  template<typename _RandomAccessIterator, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    inline void
+    sort(_RandomAccessIterator __first, _RandomAccessIterator __last,
+	 _Compare __comp)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
+	    _RandomAccessIterator>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
+	    typename iterator_traits<_RandomAccessIterator>::value_type,
+	    typename iterator_traits<_RandomAccessIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+      __glibcxx_requires_irreflexive_pred(__first, __last, __comp);
+
+      std::__sort(__first, __last, __gnu_cxx::__ops::__iter_comp_iter(__comp));
+    }
+
+  template<typename _InputIterator1, typename _InputIterator2,
+	   typename _OutputIterator, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    _OutputIterator
+    __merge(_InputIterator1 __first1, _InputIterator1 __last1,
+	    _InputIterator2 __first2, _InputIterator2 __last2,
+	    _OutputIterator __result, _Compare __comp)
+    {
+      while (__first1 != __last1 && __first2 != __last2)
+	{
+	  if (__comp(__first2, __first1))
+	    {
+	      *__result = *__first2;
+	      ++__first2;
+	    }
+	  else
+	    {
+	      *__result = *__first1;
+	      ++__first1;
+	    }
+	  ++__result;
+	}
+      return std::copy(__first2, __last2,
+		       std::copy(__first1, __last1, __result));
+    }
+
+  /**
+   *  @brief Merges two sorted ranges.
+   *  @ingroup sorting_algorithms
+   *  @param  __first1  An iterator.
+   *  @param  __first2  Another iterator.
+   *  @param  __last1   Another iterator.
+   *  @param  __last2   Another iterator.
+   *  @param  __result  An iterator pointing to the end of the merged range.
+   *  @return   An output iterator equal to @p __result + (__last1 - __first1)
+   *            + (__last2 - __first2).
+   *
+   *  Merges the ranges @p [__first1,__last1) and @p [__first2,__last2) into
+   *  the sorted range @p [__result, __result + (__last1-__first1) +
+   *  (__last2-__first2)).  Both input ranges must be sorted, and the
+   *  output range must not overlap with either of the input ranges.
+   *  The sort is @e stable, that is, for equivalent elements in the
+   *  two ranges, elements from the first range will always come
+   *  before elements from the second.
+  */
+  template<typename _InputIterator1, typename _InputIterator2,
+	   typename _OutputIterator>
+    _GLIBCXX20_CONSTEXPR
+    inline _OutputIterator
+    merge(_InputIterator1 __first1, _InputIterator1 __last1,
+	  _InputIterator2 __first2, _InputIterator2 __last2,
+	  _OutputIterator __result)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
+	    typename iterator_traits<_InputIterator1>::value_type>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
+	    typename iterator_traits<_InputIterator2>::value_type>)
+      __glibcxx_function_requires(_LessThanOpConcept<
+	    typename iterator_traits<_InputIterator2>::value_type,
+	    typename iterator_traits<_InputIterator1>::value_type>)	
+      __glibcxx_requires_sorted_set(__first1, __last1, __first2);
+      __glibcxx_requires_sorted_set(__first2, __last2, __first1);
+      __glibcxx_requires_irreflexive2(__first1, __last1);
+      __glibcxx_requires_irreflexive2(__first2, __last2);
+
+      return _GLIBCXX_STD_A::__merge(__first1, __last1,
+				     __first2, __last2, __result,
+				     __gnu_cxx::__ops::__iter_less_iter());
+    }
+
+  /**
+   *  @brief Merges two sorted ranges.
+   *  @ingroup sorting_algorithms
+   *  @param  __first1  An iterator.
+   *  @param  __first2  Another iterator.
+   *  @param  __last1   Another iterator.
+   *  @param  __last2   Another iterator.
+   *  @param  __result  An iterator pointing to the end of the merged range.
+   *  @param  __comp    A functor to use for comparisons.
+   *  @return   An output iterator equal to @p __result + (__last1 - __first1)
+   *            + (__last2 - __first2).
+   *
+   *  Merges the ranges @p [__first1,__last1) and @p [__first2,__last2) into
+   *  the sorted range @p [__result, __result + (__last1-__first1) +
+   *  (__last2-__first2)).  Both input ranges must be sorted, and the
+   *  output range must not overlap with either of the input ranges.
+   *  The sort is @e stable, that is, for equivalent elements in the
+   *  two ranges, elements from the first range will always come
+   *  before elements from the second.
+   *
+   *  The comparison function should have the same effects on ordering as
+   *  the function used for the initial sort.
+  */
+  template<typename _InputIterator1, typename _InputIterator2,
+	   typename _OutputIterator, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    inline _OutputIterator
+    merge(_InputIterator1 __first1, _InputIterator1 __last1,
+	  _InputIterator2 __first2, _InputIterator2 __last2,
+	  _OutputIterator __result, _Compare __comp)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
+	    typename iterator_traits<_InputIterator1>::value_type>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
+	    typename iterator_traits<_InputIterator2>::value_type>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
+	    typename iterator_traits<_InputIterator2>::value_type,
+	    typename iterator_traits<_InputIterator1>::value_type>)
+      __glibcxx_requires_sorted_set_pred(__first1, __last1, __first2, __comp);
+      __glibcxx_requires_sorted_set_pred(__first2, __last2, __first1, __comp);
+      __glibcxx_requires_irreflexive_pred2(__first1, __last1, __comp);
+      __glibcxx_requires_irreflexive_pred2(__first2, __last2, __comp);
+
+      return _GLIBCXX_STD_A::__merge(__first1, __last1,
+				__first2, __last2, __result,
+				__gnu_cxx::__ops::__iter_comp_iter(__comp));
+    }
+
+  template<typename _RandomAccessIterator, typename _Compare>
+    inline void
+    __stable_sort(_RandomAccessIterator __first, _RandomAccessIterator __last,
+		  _Compare __comp)
+    {
+      typedef typename iterator_traits<_RandomAccessIterator>::value_type
+	_ValueType;
+      typedef typename iterator_traits<_RandomAccessIterator>::difference_type
+	_DistanceType;
+      typedef _Temporary_buffer<_RandomAccessIterator, _ValueType> _TmpBuf;
+
+      if (__first == __last)
+	return;
+
+      // __stable_sort_adaptive sorts the range in two halves,
+      // so the buffer only needs to fit half the range at once.
+      _TmpBuf __buf(__first, (__last - __first + 1) / 2);
+
+      if (__buf.begin() == 0)
+	std::__inplace_stable_sort(__first, __last, __comp);
+      else
+	std::__stable_sort_adaptive(__first, __last, __buf.begin(),
+				    _DistanceType(__buf.size()), __comp);
+    }
+
+  /**
+   *  @brief Sort the elements of a sequence, preserving the relative order
+   *         of equivalent elements.
+   *  @ingroup sorting_algorithms
+   *  @param  __first   An iterator.
+   *  @param  __last    Another iterator.
+   *  @return  Nothing.
+   *
+   *  Sorts the elements in the range @p [__first,__last) in ascending order,
+   *  such that for each iterator @p i in the range @p [__first,__last-1),
+   *  @p *(i+1)<*i is false.
+   *
+   *  The relative ordering of equivalent elements is preserved, so any two
+   *  elements @p x and @p y in the range @p [__first,__last) such that
+   *  @p x<y is false and @p y<x is false will have the same relative
+   *  ordering after calling @p stable_sort().
+  */
+  template<typename _RandomAccessIterator>
+    inline void
+    stable_sort(_RandomAccessIterator __first, _RandomAccessIterator __last)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
+	    _RandomAccessIterator>)
+      __glibcxx_function_requires(_LessThanComparableConcept<
+	    typename iterator_traits<_RandomAccessIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+      __glibcxx_requires_irreflexive(__first, __last);
+
+      _GLIBCXX_STD_A::__stable_sort(__first, __last,
+				    __gnu_cxx::__ops::__iter_less_iter());
+    }
+
+  /**
+   *  @brief Sort the elements of a sequence using a predicate for comparison,
+   *         preserving the relative order of equivalent elements.
+   *  @ingroup sorting_algorithms
+   *  @param  __first   An iterator.
+   *  @param  __last    Another iterator.
+   *  @param  __comp    A comparison functor.
+   *  @return  Nothing.
+   *
+   *  Sorts the elements in the range @p [__first,__last) in ascending order,
+   *  such that for each iterator @p i in the range @p [__first,__last-1),
+   *  @p __comp(*(i+1),*i) is false.
+   *
+   *  The relative ordering of equivalent elements is preserved, so any two
+   *  elements @p x and @p y in the range @p [__first,__last) such that
+   *  @p __comp(x,y) is false and @p __comp(y,x) is false will have the same
+   *  relative ordering after calling @p stable_sort().
+  */
+  template<typename _RandomAccessIterator, typename _Compare>
+    inline void
+    stable_sort(_RandomAccessIterator __first, _RandomAccessIterator __last,
+		_Compare __comp)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
+	    _RandomAccessIterator>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
+	    typename iterator_traits<_RandomAccessIterator>::value_type,
+	    typename iterator_traits<_RandomAccessIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+      __glibcxx_requires_irreflexive_pred(__first, __last, __comp);
+
+      _GLIBCXX_STD_A::__stable_sort(__first, __last,
+				    __gnu_cxx::__ops::__iter_comp_iter(__comp));
+    }
+
+  template<typename _InputIterator1, typename _InputIterator2,
+	   typename _OutputIterator,
+	   typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    _OutputIterator
+    __set_union(_InputIterator1 __first1, _InputIterator1 __last1,
+		_InputIterator2 __first2, _InputIterator2 __last2,
+		_OutputIterator __result, _Compare __comp)
+    {
+      while (__first1 != __last1 && __first2 != __last2)
+	{
+	  if (__comp(__first1, __first2))
+	    {
+	      *__result = *__first1;
+	      ++__first1;
+	    }
+	  else if (__comp(__first2, __first1))
+	    {
+	      *__result = *__first2;
+	      ++__first2;
+	    }
+	  else
+	    {
+	      *__result = *__first1;
+	      ++__first1;
+	      ++__first2;
+	    }
+	  ++__result;
+	}
+      return std::copy(__first2, __last2,
+		       std::copy(__first1, __last1, __result));
+    }
+
+  /**
+   *  @brief Return the union of two sorted ranges.
+   *  @ingroup set_algorithms
+   *  @param  __first1  Start of first range.
+   *  @param  __last1   End of first range.
+   *  @param  __first2  Start of second range.
+   *  @param  __last2   End of second range.
+   *  @param  __result  Start of output range.
+   *  @return  End of the output range.
+   *  @ingroup set_algorithms
+   *
+   *  This operation iterates over both ranges, copying elements present in
+   *  each range in order to the output range.  Iterators increment for each
+   *  range.  When the current element of one range is less than the other,
+   *  that element is copied and the iterator advanced.  If an element is
+   *  contained in both ranges, the element from the first range is copied and
+   *  both ranges advance.  The output range may not overlap either input
+   *  range.
+  */
+  template<typename _InputIterator1, typename _InputIterator2,
+	   typename _OutputIterator>
+    _GLIBCXX20_CONSTEXPR
+    inline _OutputIterator
+    set_union(_InputIterator1 __first1, _InputIterator1 __last1,
+	      _InputIterator2 __first2, _InputIterator2 __last2,
+	      _OutputIterator __result)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
+	    typename iterator_traits<_InputIterator1>::value_type>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
+	    typename iterator_traits<_InputIterator2>::value_type>)
+      __glibcxx_function_requires(_LessThanOpConcept<
+	    typename iterator_traits<_InputIterator1>::value_type,
+	    typename iterator_traits<_InputIterator2>::value_type>)
+      __glibcxx_function_requires(_LessThanOpConcept<
+	    typename iterator_traits<_InputIterator2>::value_type,
+	    typename iterator_traits<_InputIterator1>::value_type>)
+      __glibcxx_requires_sorted_set(__first1, __last1, __first2);
+      __glibcxx_requires_sorted_set(__first2, __last2, __first1);
+      __glibcxx_requires_irreflexive2(__first1, __last1);
+      __glibcxx_requires_irreflexive2(__first2, __last2);
+
+      return _GLIBCXX_STD_A::__set_union(__first1, __last1,
+				__first2, __last2, __result,
+				__gnu_cxx::__ops::__iter_less_iter());
+    }
+
+  /**
+   *  @brief Return the union of two sorted ranges using a comparison functor.
+   *  @ingroup set_algorithms
+   *  @param  __first1  Start of first range.
+   *  @param  __last1   End of first range.
+   *  @param  __first2  Start of second range.
+   *  @param  __last2   End of second range.
+   *  @param  __result  Start of output range.
+   *  @param  __comp    The comparison functor.
+   *  @return  End of the output range.
+   *  @ingroup set_algorithms
+   *
+   *  This operation iterates over both ranges, copying elements present in
+   *  each range in order to the output range.  Iterators increment for each
+   *  range.  When the current element of one range is less than the other
+   *  according to @p __comp, that element is copied and the iterator advanced.
+   *  If an equivalent element according to @p __comp is contained in both
+   *  ranges, the element from the first range is copied and both ranges
+   *  advance.  The output range may not overlap either input range.
+  */
+  template<typename _InputIterator1, typename _InputIterator2,
+	   typename _OutputIterator, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    inline _OutputIterator
+    set_union(_InputIterator1 __first1, _InputIterator1 __last1,
+	      _InputIterator2 __first2, _InputIterator2 __last2,
+	      _OutputIterator __result, _Compare __comp)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
+	    typename iterator_traits<_InputIterator1>::value_type>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
+	    typename iterator_traits<_InputIterator2>::value_type>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
+	    typename iterator_traits<_InputIterator1>::value_type,
+	    typename iterator_traits<_InputIterator2>::value_type>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
+	    typename iterator_traits<_InputIterator2>::value_type,
+	    typename iterator_traits<_InputIterator1>::value_type>)
+      __glibcxx_requires_sorted_set_pred(__first1, __last1, __first2, __comp);
+      __glibcxx_requires_sorted_set_pred(__first2, __last2, __first1, __comp);
+      __glibcxx_requires_irreflexive_pred2(__first1, __last1, __comp);
+      __glibcxx_requires_irreflexive_pred2(__first2, __last2, __comp);
+
+      return _GLIBCXX_STD_A::__set_union(__first1, __last1,
+				__first2, __last2, __result,
+				__gnu_cxx::__ops::__iter_comp_iter(__comp));
+    }
+
+  template<typename _InputIterator1, typename _InputIterator2,
+	   typename _OutputIterator,
+	   typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    _OutputIterator
+    __set_intersection(_InputIterator1 __first1, _InputIterator1 __last1,
+		       _InputIterator2 __first2, _InputIterator2 __last2,
+		       _OutputIterator __result, _Compare __comp)
+    {
+      while (__first1 != __last1 && __first2 != __last2)
+	if (__comp(__first1, __first2))
+	  ++__first1;
+	else if (__comp(__first2, __first1))
+	  ++__first2;
+	else
+	  {
+	    *__result = *__first1;
+	    ++__first1;
+	    ++__first2;
+	    ++__result;
+	  }
+      return __result;
+    }
+
+  /**
+   *  @brief Return the intersection of two sorted ranges.
+   *  @ingroup set_algorithms
+   *  @param  __first1  Start of first range.
+   *  @param  __last1   End of first range.
+   *  @param  __first2  Start of second range.
+   *  @param  __last2   End of second range.
+   *  @param  __result  Start of output range.
+   *  @return  End of the output range.
+   *  @ingroup set_algorithms
+   *
+   *  This operation iterates over both ranges, copying elements present in
+   *  both ranges in order to the output range.  Iterators increment for each
+   *  range.  When the current element of one range is less than the other,
+   *  that iterator advances.  If an element is contained in both ranges, the
+   *  element from the first range is copied and both ranges advance.  The
+   *  output range may not overlap either input range.
+  */
+  template<typename _InputIterator1, typename _InputIterator2,
+	   typename _OutputIterator>
+    _GLIBCXX20_CONSTEXPR
+    inline _OutputIterator
+    set_intersection(_InputIterator1 __first1, _InputIterator1 __last1,
+		     _InputIterator2 __first2, _InputIterator2 __last2,
+		     _OutputIterator __result)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
+	    typename iterator_traits<_InputIterator1>::value_type>)
+      __glibcxx_function_requires(_LessThanOpConcept<
+	    typename iterator_traits<_InputIterator1>::value_type,
+	    typename iterator_traits<_InputIterator2>::value_type>)
+      __glibcxx_function_requires(_LessThanOpConcept<
+	    typename iterator_traits<_InputIterator2>::value_type,
+	    typename iterator_traits<_InputIterator1>::value_type>)
+      __glibcxx_requires_sorted_set(__first1, __last1, __first2);
+      __glibcxx_requires_sorted_set(__first2, __last2, __first1);
+      __glibcxx_requires_irreflexive2(__first1, __last1);
+      __glibcxx_requires_irreflexive2(__first2, __last2);
+
+      return _GLIBCXX_STD_A::__set_intersection(__first1, __last1,
+				     __first2, __last2, __result,
+				     __gnu_cxx::__ops::__iter_less_iter());
+    }
+
+  /**
+   *  @brief Return the intersection of two sorted ranges using comparison
+   *  functor.
+   *  @ingroup set_algorithms
+   *  @param  __first1  Start of first range.
+   *  @param  __last1   End of first range.
+   *  @param  __first2  Start of second range.
+   *  @param  __last2   End of second range.
+   *  @param  __result  Start of output range.
+   *  @param  __comp    The comparison functor.
+   *  @return  End of the output range.
+   *  @ingroup set_algorithms
+   *
+   *  This operation iterates over both ranges, copying elements present in
+   *  both ranges in order to the output range.  Iterators increment for each
+   *  range.  When the current element of one range is less than the other
+   *  according to @p __comp, that iterator advances.  If an element is
+   *  contained in both ranges according to @p __comp, the element from the
+   *  first range is copied and both ranges advance.  The output range may not
+   *  overlap either input range.
+  */
+  template<typename _InputIterator1, typename _InputIterator2,
+	   typename _OutputIterator, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    inline _OutputIterator
+    set_intersection(_InputIterator1 __first1, _InputIterator1 __last1,
+		     _InputIterator2 __first2, _InputIterator2 __last2,
+		     _OutputIterator __result, _Compare __comp)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
+	    typename iterator_traits<_InputIterator1>::value_type>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
+	    typename iterator_traits<_InputIterator1>::value_type,
+	    typename iterator_traits<_InputIterator2>::value_type>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
+	    typename iterator_traits<_InputIterator2>::value_type,
+	    typename iterator_traits<_InputIterator1>::value_type>)
+      __glibcxx_requires_sorted_set_pred(__first1, __last1, __first2, __comp);
+      __glibcxx_requires_sorted_set_pred(__first2, __last2, __first1, __comp);
+      __glibcxx_requires_irreflexive_pred2(__first1, __last1, __comp);
+      __glibcxx_requires_irreflexive_pred2(__first2, __last2, __comp);
+
+      return _GLIBCXX_STD_A::__set_intersection(__first1, __last1,
+				__first2, __last2, __result,
+				__gnu_cxx::__ops::__iter_comp_iter(__comp));
+    }
+
+  template<typename _InputIterator1, typename _InputIterator2,
+	   typename _OutputIterator,
+	   typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    _OutputIterator
+    __set_difference(_InputIterator1 __first1, _InputIterator1 __last1,
+		     _InputIterator2 __first2, _InputIterator2 __last2,
+		     _OutputIterator __result, _Compare __comp)
+    {
+      while (__first1 != __last1 && __first2 != __last2)
+	if (__comp(__first1, __first2))
+	  {
+	    *__result = *__first1;
+	    ++__first1;
+	    ++__result;
+	  }
+	else if (__comp(__first2, __first1))
+	  ++__first2;
+	else
+	  {
+	    ++__first1;
+	    ++__first2;
+	  }
+      return std::copy(__first1, __last1, __result);
+    }
+
+  /**
+   *  @brief Return the difference of two sorted ranges.
+   *  @ingroup set_algorithms
+   *  @param  __first1  Start of first range.
+   *  @param  __last1   End of first range.
+   *  @param  __first2  Start of second range.
+   *  @param  __last2   End of second range.
+   *  @param  __result  Start of output range.
+   *  @return  End of the output range.
+   *  @ingroup set_algorithms
+   *
+   *  This operation iterates over both ranges, copying elements present in
+   *  the first range but not the second in order to the output range.
+   *  Iterators increment for each range.  When the current element of the
+   *  first range is less than the second, that element is copied and the
+   *  iterator advances.  If the current element of the second range is less,
+   *  the iterator advances, but no element is copied.  If an element is
+   *  contained in both ranges, no elements are copied and both ranges
+   *  advance.  The output range may not overlap either input range.
+  */
+  template<typename _InputIterator1, typename _InputIterator2,
+	   typename _OutputIterator>
+    _GLIBCXX20_CONSTEXPR
+    inline _OutputIterator
+    set_difference(_InputIterator1 __first1, _InputIterator1 __last1,
+		   _InputIterator2 __first2, _InputIterator2 __last2,
+		   _OutputIterator __result)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
+	    typename iterator_traits<_InputIterator1>::value_type>)
+      __glibcxx_function_requires(_LessThanOpConcept<
+	    typename iterator_traits<_InputIterator1>::value_type,
+	    typename iterator_traits<_InputIterator2>::value_type>)
+      __glibcxx_function_requires(_LessThanOpConcept<
+	    typename iterator_traits<_InputIterator2>::value_type,
+	    typename iterator_traits<_InputIterator1>::value_type>)	
+      __glibcxx_requires_sorted_set(__first1, __last1, __first2);
+      __glibcxx_requires_sorted_set(__first2, __last2, __first1);
+      __glibcxx_requires_irreflexive2(__first1, __last1);
+      __glibcxx_requires_irreflexive2(__first2, __last2);
+
+      return _GLIBCXX_STD_A::__set_difference(__first1, __last1,
+				   __first2, __last2, __result,
+				   __gnu_cxx::__ops::__iter_less_iter());
+    }
+
+  /**
+   *  @brief  Return the difference of two sorted ranges using comparison
+   *  functor.
+   *  @ingroup set_algorithms
+   *  @param  __first1  Start of first range.
+   *  @param  __last1   End of first range.
+   *  @param  __first2  Start of second range.
+   *  @param  __last2   End of second range.
+   *  @param  __result  Start of output range.
+   *  @param  __comp    The comparison functor.
+   *  @return  End of the output range.
+   *  @ingroup set_algorithms
+   *
+   *  This operation iterates over both ranges, copying elements present in
+   *  the first range but not the second in order to the output range.
+   *  Iterators increment for each range.  When the current element of the
+   *  first range is less than the second according to @p __comp, that element
+   *  is copied and the iterator advances.  If the current element of the
+   *  second range is less, no element is copied and the iterator advances.
+   *  If an element is contained in both ranges according to @p __comp, no
+   *  elements are copied and both ranges advance.  The output range may not
+   *  overlap either input range.
+  */
+  template<typename _InputIterator1, typename _InputIterator2,
+	   typename _OutputIterator, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    inline _OutputIterator
+    set_difference(_InputIterator1 __first1, _InputIterator1 __last1,
+		   _InputIterator2 __first2, _InputIterator2 __last2,
+		   _OutputIterator __result, _Compare __comp)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
+	    typename iterator_traits<_InputIterator1>::value_type>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
+	    typename iterator_traits<_InputIterator1>::value_type,
+	    typename iterator_traits<_InputIterator2>::value_type>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
+	    typename iterator_traits<_InputIterator2>::value_type,
+	    typename iterator_traits<_InputIterator1>::value_type>)
+      __glibcxx_requires_sorted_set_pred(__first1, __last1, __first2, __comp);
+      __glibcxx_requires_sorted_set_pred(__first2, __last2, __first1, __comp);
+      __glibcxx_requires_irreflexive_pred2(__first1, __last1, __comp);
+      __glibcxx_requires_irreflexive_pred2(__first2, __last2, __comp);
+
+      return _GLIBCXX_STD_A::__set_difference(__first1, __last1,
+				   __first2, __last2, __result,
+				   __gnu_cxx::__ops::__iter_comp_iter(__comp));
+    }
+
+  template<typename _InputIterator1, typename _InputIterator2,
+	   typename _OutputIterator,
+	   typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    _OutputIterator
+    __set_symmetric_difference(_InputIterator1 __first1,
+			       _InputIterator1 __last1,
+			       _InputIterator2 __first2,
+			       _InputIterator2 __last2,
+			       _OutputIterator __result,
+			       _Compare __comp)
+    {
+      while (__first1 != __last1 && __first2 != __last2)
+	if (__comp(__first1, __first2))
+	  {
+	    *__result = *__first1;
+	    ++__first1;
+	    ++__result;
+	  }
+	else if (__comp(__first2, __first1))
+	  {
+	    *__result = *__first2;
+	    ++__first2;
+	    ++__result;
+	  }
+	else
+	  {
+	    ++__first1;
+	    ++__first2;
+	  }
+      return std::copy(__first2, __last2, 
+		       std::copy(__first1, __last1, __result));
+    }
+
+  /**
+   *  @brief  Return the symmetric difference of two sorted ranges.
+   *  @ingroup set_algorithms
+   *  @param  __first1  Start of first range.
+   *  @param  __last1   End of first range.
+   *  @param  __first2  Start of second range.
+   *  @param  __last2   End of second range.
+   *  @param  __result  Start of output range.
+   *  @return  End of the output range.
+   *  @ingroup set_algorithms
+   *
+   *  This operation iterates over both ranges, copying elements present in
+   *  one range but not the other in order to the output range.  Iterators
+   *  increment for each range.  When the current element of one range is less
+   *  than the other, that element is copied and the iterator advances.  If an
+   *  element is contained in both ranges, no elements are copied and both
+   *  ranges advance.  The output range may not overlap either input range.
+  */
+  template<typename _InputIterator1, typename _InputIterator2,
+	   typename _OutputIterator>
+    _GLIBCXX20_CONSTEXPR
+    inline _OutputIterator
+    set_symmetric_difference(_InputIterator1 __first1, _InputIterator1 __last1,
+			     _InputIterator2 __first2, _InputIterator2 __last2,
+			     _OutputIterator __result)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
+	    typename iterator_traits<_InputIterator1>::value_type>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
+	    typename iterator_traits<_InputIterator2>::value_type>)
+      __glibcxx_function_requires(_LessThanOpConcept<
+	    typename iterator_traits<_InputIterator1>::value_type,
+	    typename iterator_traits<_InputIterator2>::value_type>)
+      __glibcxx_function_requires(_LessThanOpConcept<
+	    typename iterator_traits<_InputIterator2>::value_type,
+	    typename iterator_traits<_InputIterator1>::value_type>)	
+      __glibcxx_requires_sorted_set(__first1, __last1, __first2);
+      __glibcxx_requires_sorted_set(__first2, __last2, __first1);
+      __glibcxx_requires_irreflexive2(__first1, __last1);
+      __glibcxx_requires_irreflexive2(__first2, __last2);
+
+      return _GLIBCXX_STD_A::__set_symmetric_difference(__first1, __last1,
+					__first2, __last2, __result,
+					__gnu_cxx::__ops::__iter_less_iter());
+    }
+
+  /**
+   *  @brief  Return the symmetric difference of two sorted ranges using
+   *  comparison functor.
+   *  @ingroup set_algorithms
+   *  @param  __first1  Start of first range.
+   *  @param  __last1   End of first range.
+   *  @param  __first2  Start of second range.
+   *  @param  __last2   End of second range.
+   *  @param  __result  Start of output range.
+   *  @param  __comp    The comparison functor.
+   *  @return  End of the output range.
+   *  @ingroup set_algorithms
+   *
+   *  This operation iterates over both ranges, copying elements present in
+   *  one range but not the other in order to the output range.  Iterators
+   *  increment for each range.  When the current element of one range is less
+   *  than the other according to @p comp, that element is copied and the
+   *  iterator advances.  If an element is contained in both ranges according
+   *  to @p __comp, no elements are copied and both ranges advance.  The output
+   *  range may not overlap either input range.
+  */
+  template<typename _InputIterator1, typename _InputIterator2,
+	   typename _OutputIterator, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    inline _OutputIterator
+    set_symmetric_difference(_InputIterator1 __first1, _InputIterator1 __last1,
+			     _InputIterator2 __first2, _InputIterator2 __last2,
+			     _OutputIterator __result,
+			     _Compare __comp)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
+	    typename iterator_traits<_InputIterator1>::value_type>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
+	    typename iterator_traits<_InputIterator2>::value_type>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
+	    typename iterator_traits<_InputIterator1>::value_type,
+	    typename iterator_traits<_InputIterator2>::value_type>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
+	    typename iterator_traits<_InputIterator2>::value_type,
+	    typename iterator_traits<_InputIterator1>::value_type>)
+      __glibcxx_requires_sorted_set_pred(__first1, __last1, __first2, __comp);
+      __glibcxx_requires_sorted_set_pred(__first2, __last2, __first1, __comp);
+      __glibcxx_requires_irreflexive_pred2(__first1, __last1, __comp);
+      __glibcxx_requires_irreflexive_pred2(__first2, __last2, __comp);
+
+      return _GLIBCXX_STD_A::__set_symmetric_difference(__first1, __last1,
+				__first2, __last2, __result,
+				__gnu_cxx::__ops::__iter_comp_iter(__comp));
+    }
+
+  template<typename _ForwardIterator, typename _Compare>
+    _GLIBCXX14_CONSTEXPR
+    _ForwardIterator
+    __min_element(_ForwardIterator __first, _ForwardIterator __last,
+		  _Compare __comp)
+    {
+      if (__first == __last)
+	return __first;
+      _ForwardIterator __result = __first;
+      while (++__first != __last)
+	if (__comp(__first, __result))
+	  __result = __first;
+      return __result;
+    }
+
+  /**
+   *  @brief  Return the minimum element in a range.
+   *  @ingroup sorting_algorithms
+   *  @param  __first  Start of range.
+   *  @param  __last   End of range.
+   *  @return  Iterator referencing the first instance of the smallest value.
+  */
+  template<typename _ForwardIterator>
+    _GLIBCXX14_CONSTEXPR
+    _ForwardIterator
+    inline min_element(_ForwardIterator __first, _ForwardIterator __last)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+      __glibcxx_function_requires(_LessThanComparableConcept<
+	    typename iterator_traits<_ForwardIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+      __glibcxx_requires_irreflexive(__first, __last);
+
+      return _GLIBCXX_STD_A::__min_element(__first, __last,
+				__gnu_cxx::__ops::__iter_less_iter());
+    }
+
+  /**
+   *  @brief  Return the minimum element in a range using comparison functor.
+   *  @ingroup sorting_algorithms
+   *  @param  __first  Start of range.
+   *  @param  __last   End of range.
+   *  @param  __comp   Comparison functor.
+   *  @return  Iterator referencing the first instance of the smallest value
+   *  according to __comp.
+  */
+  template<typename _ForwardIterator, typename _Compare>
+    _GLIBCXX14_CONSTEXPR
+    inline _ForwardIterator
+    min_element(_ForwardIterator __first, _ForwardIterator __last,
+		_Compare __comp)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
+	    typename iterator_traits<_ForwardIterator>::value_type,
+	    typename iterator_traits<_ForwardIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+      __glibcxx_requires_irreflexive_pred(__first, __last, __comp);
+
+      return _GLIBCXX_STD_A::__min_element(__first, __last,
+				__gnu_cxx::__ops::__iter_comp_iter(__comp));
+    }
+
+  template<typename _ForwardIterator, typename _Compare>
+    _GLIBCXX14_CONSTEXPR
+    _ForwardIterator
+    __max_element(_ForwardIterator __first, _ForwardIterator __last,
+		  _Compare __comp)
+    {
+      if (__first == __last) return __first;
+      _ForwardIterator __result = __first;
+      while (++__first != __last)
+	if (__comp(__result, __first))
+	  __result = __first;
+      return __result;
+    }
+
+  /**
+   *  @brief  Return the maximum element in a range.
+   *  @ingroup sorting_algorithms
+   *  @param  __first  Start of range.
+   *  @param  __last   End of range.
+   *  @return  Iterator referencing the first instance of the largest value.
+  */
+  template<typename _ForwardIterator>
+    _GLIBCXX14_CONSTEXPR
+    inline _ForwardIterator
+    max_element(_ForwardIterator __first, _ForwardIterator __last)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+      __glibcxx_function_requires(_LessThanComparableConcept<
+	    typename iterator_traits<_ForwardIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+      __glibcxx_requires_irreflexive(__first, __last);
+
+      return _GLIBCXX_STD_A::__max_element(__first, __last,
+				__gnu_cxx::__ops::__iter_less_iter());
+    }
+
+  /**
+   *  @brief  Return the maximum element in a range using comparison functor.
+   *  @ingroup sorting_algorithms
+   *  @param  __first  Start of range.
+   *  @param  __last   End of range.
+   *  @param  __comp   Comparison functor.
+   *  @return  Iterator referencing the first instance of the largest value
+   *  according to __comp.
+  */
+  template<typename _ForwardIterator, typename _Compare>
+    _GLIBCXX14_CONSTEXPR
+    inline _ForwardIterator
+    max_element(_ForwardIterator __first, _ForwardIterator __last,
+		_Compare __comp)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
+	    typename iterator_traits<_ForwardIterator>::value_type,
+	    typename iterator_traits<_ForwardIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+      __glibcxx_requires_irreflexive_pred(__first, __last, __comp);
+
+      return _GLIBCXX_STD_A::__max_element(__first, __last,
+				__gnu_cxx::__ops::__iter_comp_iter(__comp));
+    }
+
+#if __cplusplus >= 201103L
+  // N2722 + DR 915.
+  template<typename _Tp>
+    _GLIBCXX14_CONSTEXPR
+    inline _Tp
+    min(initializer_list<_Tp> __l)
+    {
+      __glibcxx_requires_irreflexive(__l.begin(), __l.end());
+      return *_GLIBCXX_STD_A::__min_element(__l.begin(), __l.end(),
+	  __gnu_cxx::__ops::__iter_less_iter());
+    }
+
+  template<typename _Tp, typename _Compare>
+    _GLIBCXX14_CONSTEXPR
+    inline _Tp
+    min(initializer_list<_Tp> __l, _Compare __comp)
+    {
+      __glibcxx_requires_irreflexive_pred(__l.begin(), __l.end(), __comp);
+      return *_GLIBCXX_STD_A::__min_element(__l.begin(), __l.end(),
+	  __gnu_cxx::__ops::__iter_comp_iter(__comp));
+    }
+
+  template<typename _Tp>
+    _GLIBCXX14_CONSTEXPR
+    inline _Tp
+    max(initializer_list<_Tp> __l)
+    {
+      __glibcxx_requires_irreflexive(__l.begin(), __l.end());
+      return *_GLIBCXX_STD_A::__max_element(__l.begin(), __l.end(),
+	  __gnu_cxx::__ops::__iter_less_iter());
+    }
+
+  template<typename _Tp, typename _Compare>
+    _GLIBCXX14_CONSTEXPR
+    inline _Tp
+    max(initializer_list<_Tp> __l, _Compare __comp)
+    {
+      __glibcxx_requires_irreflexive_pred(__l.begin(), __l.end(), __comp);
+      return *_GLIBCXX_STD_A::__max_element(__l.begin(), __l.end(),
+	  __gnu_cxx::__ops::__iter_comp_iter(__comp));
+    }
+#endif // C++11
+
+#if __cplusplus >= 201402L
+  /// Reservoir sampling algorithm.
+  template<typename _InputIterator, typename _RandomAccessIterator,
+           typename _Size, typename _UniformRandomBitGenerator>
+    _RandomAccessIterator
+    __sample(_InputIterator __first, _InputIterator __last, input_iterator_tag,
+	     _RandomAccessIterator __out, random_access_iterator_tag,
+	     _Size __n, _UniformRandomBitGenerator&& __g)
+    {
+      using __distrib_type = uniform_int_distribution<_Size>;
+      using __param_type = typename __distrib_type::param_type;
+      __distrib_type __d{};
+      _Size __sample_sz = 0;
+      while (__first != __last && __sample_sz != __n)
+	{
+	  __out[__sample_sz++] = *__first;
+	  ++__first;
+	}
+      for (auto __pop_sz = __sample_sz; __first != __last;
+	  ++__first, (void) ++__pop_sz)
+	{
+	  const auto __k = __d(__g, __param_type{0, __pop_sz});
+	  if (__k < __n)
+	    __out[__k] = *__first;
+	}
+      return __out + __sample_sz;
+    }
+
+  /// Selection sampling algorithm.
+  template<typename _ForwardIterator, typename _OutputIterator, typename _Cat,
+           typename _Size, typename _UniformRandomBitGenerator>
+    _OutputIterator
+    __sample(_ForwardIterator __first, _ForwardIterator __last,
+	     forward_iterator_tag,
+	     _OutputIterator __out, _Cat,
+	     _Size __n, _UniformRandomBitGenerator&& __g)
+    {
+      using __distrib_type = uniform_int_distribution<_Size>;
+      using __param_type = typename __distrib_type::param_type;
+      using _USize = make_unsigned_t<_Size>;
+      using _Gen = remove_reference_t<_UniformRandomBitGenerator>;
+      using __uc_type = common_type_t<typename _Gen::result_type, _USize>;
+
+      if (__first == __last)
+	return __out;
+
+      __distrib_type __d{};
+      _Size __unsampled_sz = std::distance(__first, __last);
+      __n = std::min(__n, __unsampled_sz);
+
+      // If possible, we use __gen_two_uniform_ints to efficiently produce
+      // two random numbers using a single distribution invocation:
+
+      const __uc_type __urngrange = __g.max() - __g.min();
+      if (__urngrange / __uc_type(__unsampled_sz) >= __uc_type(__unsampled_sz))
+        // I.e. (__urngrange >= __unsampled_sz * __unsampled_sz) but without
+	// wrapping issues.
+        {
+	  while (__n != 0 && __unsampled_sz >= 2)
+	    {
+	      const pair<_Size, _Size> __p =
+		__gen_two_uniform_ints(__unsampled_sz, __unsampled_sz - 1, __g);
+
+	      --__unsampled_sz;
+	      if (__p.first < __n)
+		{
+		  *__out++ = *__first;
+		  --__n;
+		}
+
+	      ++__first;
+
+	      if (__n == 0) break;
+
+	      --__unsampled_sz;
+	      if (__p.second < __n)
+		{
+		  *__out++ = *__first;
+		  --__n;
+		}
+
+	      ++__first;
+	    }
+        }
+
+      // The loop above is otherwise equivalent to this one-at-a-time version:
+
+      for (; __n != 0; ++__first)
+	if (__d(__g, __param_type{0, --__unsampled_sz}) < __n)
+	  {
+	    *__out++ = *__first;
+	    --__n;
+	  }
+      return __out;
+    }
+
+#if __cplusplus > 201402L
+#define __cpp_lib_sample 201603L
+  /// Take a random sample from a population.
+  template<typename _PopulationIterator, typename _SampleIterator,
+           typename _Distance, typename _UniformRandomBitGenerator>
+    _SampleIterator
+    sample(_PopulationIterator __first, _PopulationIterator __last,
+	   _SampleIterator __out, _Distance __n,
+	   _UniformRandomBitGenerator&& __g)
+    {
+      using __pop_cat = typename
+	std::iterator_traits<_PopulationIterator>::iterator_category;
+      using __samp_cat = typename
+	std::iterator_traits<_SampleIterator>::iterator_category;
+
+      static_assert(
+	  __or_<is_convertible<__pop_cat, forward_iterator_tag>,
+		is_convertible<__samp_cat, random_access_iterator_tag>>::value,
+	  "output range must use a RandomAccessIterator when input range"
+	  " does not meet the ForwardIterator requirements");
+
+      static_assert(is_integral<_Distance>::value,
+		    "sample size must be an integer type");
+
+      typename iterator_traits<_PopulationIterator>::difference_type __d = __n;
+      return _GLIBCXX_STD_A::
+	__sample(__first, __last, __pop_cat{}, __out, __samp_cat{}, __d,
+		 std::forward<_UniformRandomBitGenerator>(__g));
+    }
+#endif // C++17
+#endif // C++14
+
+_GLIBCXX_END_NAMESPACE_ALGO
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif /* _STL_ALGO_H */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stl_algo.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stl_algo.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stl_algobase.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stl_algobase.h
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stl_algobase.h
@@ -0,0 +1,2228 @@
+// Core algorithmic facilities -*- C++ -*-
+
+// Copyright (C) 2001-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/*
+ *
+ * Copyright (c) 1994
+ * Hewlett-Packard Company
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Hewlett-Packard Company makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ *
+ *
+ * Copyright (c) 1996-1998
+ * Silicon Graphics Computer Systems, Inc.
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Silicon Graphics makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ */
+
+/** @file bits/stl_algobase.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{algorithm}
+ */
+
+#ifndef _STL_ALGOBASE_H
+#define _STL_ALGOBASE_H 1
+
+#include <bits/c++config.h>
+#include <bits/functexcept.h>
+#include <bits/cpp_type_traits.h>
+#include <ext/type_traits.h>
+#include <ext/numeric_traits.h>
+#include <bits/stl_pair.h>
+#include <bits/stl_iterator_base_types.h>
+#include <bits/stl_iterator_base_funcs.h>
+#include <bits/stl_iterator.h>
+#include <bits/concept_check.h>
+#include <debug/debug.h>
+#include <bits/move.h> // For std::swap
+#include <bits/predefined_ops.h>
+#if __cplusplus >= 201103L
+# include <type_traits>
+#endif
+#if __cplusplus > 201703L
+# include <compare>
+#endif
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /*
+   * A constexpr wrapper for __builtin_memcmp.
+   * @param __num The number of elements of type _Tp (not bytes).
+   */
+  template<typename _Tp, typename _Up>
+    _GLIBCXX14_CONSTEXPR
+    inline int
+    __memcmp(const _Tp* __first1, const _Up* __first2, size_t __num)
+    {
+#if __cplusplus >= 201103L
+      static_assert(sizeof(_Tp) == sizeof(_Up), "can be compared with memcmp");
+#endif
+#ifdef __cpp_lib_is_constant_evaluated
+      if (std::is_constant_evaluated())
+	{
+	  for(; __num > 0; ++__first1, ++__first2, --__num)
+	    if (*__first1 != *__first2)
+	      return *__first1 < *__first2 ? -1 : 1;
+	  return 0;
+	}
+      else
+#endif
+	return __builtin_memcmp(__first1, __first2, sizeof(_Tp) * __num);
+    }
+
+#if __cplusplus < 201103L
+  // See http://gcc.gnu.org/ml/libstdc++/2004-08/msg00167.html: in a
+  // nutshell, we are partially implementing the resolution of DR 187,
+  // when it's safe, i.e., the value_types are equal.
+  template<bool _BoolType>
+    struct __iter_swap
+    {
+      template<typename _ForwardIterator1, typename _ForwardIterator2>
+	static void
+	iter_swap(_ForwardIterator1 __a, _ForwardIterator2 __b)
+	{
+	  typedef typename iterator_traits<_ForwardIterator1>::value_type
+	    _ValueType1;
+	  _ValueType1 __tmp = *__a;
+	  *__a = *__b;
+	  *__b = __tmp;
+	}
+    };
+
+  template<>
+    struct __iter_swap<true>
+    {
+      template<typename _ForwardIterator1, typename _ForwardIterator2>
+	static void
+	iter_swap(_ForwardIterator1 __a, _ForwardIterator2 __b)
+	{
+	  swap(*__a, *__b);
+	}
+    };
+#endif // C++03
+
+  /**
+   *  @brief Swaps the contents of two iterators.
+   *  @ingroup mutating_algorithms
+   *  @param  __a  An iterator.
+   *  @param  __b  Another iterator.
+   *  @return   Nothing.
+   *
+   *  This function swaps the values pointed to by two iterators, not the
+   *  iterators themselves.
+  */
+  template<typename _ForwardIterator1, typename _ForwardIterator2>
+    _GLIBCXX20_CONSTEXPR
+    inline void
+    iter_swap(_ForwardIterator1 __a, _ForwardIterator2 __b)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
+				  _ForwardIterator1>)
+      __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
+				  _ForwardIterator2>)
+
+#if __cplusplus < 201103L
+      typedef typename iterator_traits<_ForwardIterator1>::value_type
+	_ValueType1;
+      typedef typename iterator_traits<_ForwardIterator2>::value_type
+	_ValueType2;
+
+      __glibcxx_function_requires(_ConvertibleConcept<_ValueType1,
+				  _ValueType2>)
+      __glibcxx_function_requires(_ConvertibleConcept<_ValueType2,
+				  _ValueType1>)
+
+      typedef typename iterator_traits<_ForwardIterator1>::reference
+	_ReferenceType1;
+      typedef typename iterator_traits<_ForwardIterator2>::reference
+	_ReferenceType2;
+      std::__iter_swap<__are_same<_ValueType1, _ValueType2>::__value
+	&& __are_same<_ValueType1&, _ReferenceType1>::__value
+	&& __are_same<_ValueType2&, _ReferenceType2>::__value>::
+	iter_swap(__a, __b);
+#else
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 187. iter_swap underspecified
+      swap(*__a, *__b);
+#endif
+    }
+
+  /**
+   *  @brief Swap the elements of two sequences.
+   *  @ingroup mutating_algorithms
+   *  @param  __first1  A forward iterator.
+   *  @param  __last1   A forward iterator.
+   *  @param  __first2  A forward iterator.
+   *  @return   An iterator equal to @p first2+(last1-first1).
+   *
+   *  Swaps each element in the range @p [first1,last1) with the
+   *  corresponding element in the range @p [first2,(last1-first1)).
+   *  The ranges must not overlap.
+  */
+  template<typename _ForwardIterator1, typename _ForwardIterator2>
+    _GLIBCXX20_CONSTEXPR
+    _ForwardIterator2
+    swap_ranges(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
+		_ForwardIterator2 __first2)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
+				  _ForwardIterator1>)
+      __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
+				  _ForwardIterator2>)
+      __glibcxx_requires_valid_range(__first1, __last1);
+
+      for (; __first1 != __last1; ++__first1, (void)++__first2)
+	std::iter_swap(__first1, __first2);
+      return __first2;
+    }
+
+  /**
+   *  @brief This does what you think it does.
+   *  @ingroup sorting_algorithms
+   *  @param  __a  A thing of arbitrary type.
+   *  @param  __b  Another thing of arbitrary type.
+   *  @return   The lesser of the parameters.
+   *
+   *  This is the simple classic generic implementation.  It will work on
+   *  temporary expressions, since they are only evaluated once, unlike a
+   *  preprocessor macro.
+  */
+  template<typename _Tp>
+    _GLIBCXX14_CONSTEXPR
+    inline const _Tp&
+    min(const _Tp& __a, const _Tp& __b)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_LessThanComparableConcept<_Tp>)
+      //return __b < __a ? __b : __a;
+      if (__b < __a)
+	return __b;
+      return __a;
+    }
+
+  /**
+   *  @brief This does what you think it does.
+   *  @ingroup sorting_algorithms
+   *  @param  __a  A thing of arbitrary type.
+   *  @param  __b  Another thing of arbitrary type.
+   *  @return   The greater of the parameters.
+   *
+   *  This is the simple classic generic implementation.  It will work on
+   *  temporary expressions, since they are only evaluated once, unlike a
+   *  preprocessor macro.
+  */
+  template<typename _Tp>
+    _GLIBCXX14_CONSTEXPR
+    inline const _Tp&
+    max(const _Tp& __a, const _Tp& __b)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_LessThanComparableConcept<_Tp>)
+      //return  __a < __b ? __b : __a;
+      if (__a < __b)
+	return __b;
+      return __a;
+    }
+
+  /**
+   *  @brief This does what you think it does.
+   *  @ingroup sorting_algorithms
+   *  @param  __a  A thing of arbitrary type.
+   *  @param  __b  Another thing of arbitrary type.
+   *  @param  __comp  A @link comparison_functors comparison functor@endlink.
+   *  @return   The lesser of the parameters.
+   *
+   *  This will work on temporary expressions, since they are only evaluated
+   *  once, unlike a preprocessor macro.
+  */
+  template<typename _Tp, typename _Compare>
+    _GLIBCXX14_CONSTEXPR
+    inline const _Tp&
+    min(const _Tp& __a, const _Tp& __b, _Compare __comp)
+    {
+      //return __comp(__b, __a) ? __b : __a;
+      if (__comp(__b, __a))
+	return __b;
+      return __a;
+    }
+
+  /**
+   *  @brief This does what you think it does.
+   *  @ingroup sorting_algorithms
+   *  @param  __a  A thing of arbitrary type.
+   *  @param  __b  Another thing of arbitrary type.
+   *  @param  __comp  A @link comparison_functors comparison functor@endlink.
+   *  @return   The greater of the parameters.
+   *
+   *  This will work on temporary expressions, since they are only evaluated
+   *  once, unlike a preprocessor macro.
+  */
+  template<typename _Tp, typename _Compare>
+    _GLIBCXX14_CONSTEXPR
+    inline const _Tp&
+    max(const _Tp& __a, const _Tp& __b, _Compare __comp)
+    {
+      //return __comp(__a, __b) ? __b : __a;
+      if (__comp(__a, __b))
+	return __b;
+      return __a;
+    }
+
+  // Fallback implementation of the function in bits/stl_iterator.h used to
+  // remove the __normal_iterator wrapper. See copy, fill, ...
+  template<typename _Iterator>
+    _GLIBCXX20_CONSTEXPR
+    inline _Iterator
+    __niter_base(_Iterator __it)
+    _GLIBCXX_NOEXCEPT_IF(std::is_nothrow_copy_constructible<_Iterator>::value)
+    { return __it; }
+
+  template<typename _Ite, typename _Seq>
+    _Ite
+    __niter_base(const ::__gnu_debug::_Safe_iterator<_Ite, _Seq,
+		 std::random_access_iterator_tag>&);
+
+  // Reverse the __niter_base transformation to get a
+  // __normal_iterator back again (this assumes that __normal_iterator
+  // is only used to wrap random access iterators, like pointers).
+  template<typename _From, typename _To>
+    _GLIBCXX20_CONSTEXPR
+    inline _From
+    __niter_wrap(_From __from, _To __res)
+    { return __from + (__res - std::__niter_base(__from)); }
+
+  // No need to wrap, iterator already has the right type.
+  template<typename _Iterator>
+    _GLIBCXX20_CONSTEXPR
+    inline _Iterator
+    __niter_wrap(const _Iterator&, _Iterator __res)
+    { return __res; }
+
+  // All of these auxiliary structs serve two purposes.  (1) Replace
+  // calls to copy with memmove whenever possible.  (Memmove, not memcpy,
+  // because the input and output ranges are permitted to overlap.)
+  // (2) If we're using random access iterators, then write the loop as
+  // a for loop with an explicit count.
+
+  template<bool _IsMove, bool _IsSimple, typename _Category>
+    struct __copy_move
+    {
+      template<typename _II, typename _OI>
+	_GLIBCXX20_CONSTEXPR
+	static _OI
+	__copy_m(_II __first, _II __last, _OI __result)
+	{
+	  for (; __first != __last; ++__result, (void)++__first)
+	    *__result = *__first;
+	  return __result;
+	}
+    };
+
+#if __cplusplus >= 201103L
+  template<typename _Category>
+    struct __copy_move<true, false, _Category>
+    {
+      template<typename _II, typename _OI>
+	_GLIBCXX20_CONSTEXPR
+	static _OI
+	__copy_m(_II __first, _II __last, _OI __result)
+	{
+	  for (; __first != __last; ++__result, (void)++__first)
+	    *__result = std::move(*__first);
+	  return __result;
+	}
+    };
+#endif
+
+  template<>
+    struct __copy_move<false, false, random_access_iterator_tag>
+    {
+      template<typename _II, typename _OI>
+	_GLIBCXX20_CONSTEXPR
+	static _OI
+	__copy_m(_II __first, _II __last, _OI __result)
+	{
+	  typedef typename iterator_traits<_II>::difference_type _Distance;
+	  for(_Distance __n = __last - __first; __n > 0; --__n)
+	    {
+	      *__result = *__first;
+	      ++__first;
+	      ++__result;
+	    }
+	  return __result;
+	}
+    };
+
+#if __cplusplus >= 201103L
+  template<>
+    struct __copy_move<true, false, random_access_iterator_tag>
+    {
+      template<typename _II, typename _OI>
+	_GLIBCXX20_CONSTEXPR
+	static _OI
+	__copy_m(_II __first, _II __last, _OI __result)
+	{
+	  typedef typename iterator_traits<_II>::difference_type _Distance;
+	  for(_Distance __n = __last - __first; __n > 0; --__n)
+	    {
+	      *__result = std::move(*__first);
+	      ++__first;
+	      ++__result;
+	    }
+	  return __result;
+	}
+    };
+#endif
+
+  template<bool _IsMove>
+    struct __copy_move<_IsMove, true, random_access_iterator_tag>
+    {
+      template<typename _Tp>
+	_GLIBCXX20_CONSTEXPR
+	static _Tp*
+	__copy_m(const _Tp* __first, const _Tp* __last, _Tp* __result)
+	{
+#if __cplusplus >= 201103L
+	  using __assignable = __conditional_t<_IsMove,
+					       is_move_assignable<_Tp>,
+					       is_copy_assignable<_Tp>>;
+	  // trivial types can have deleted assignment
+	  static_assert( __assignable::value, "type must be assignable" );
+#endif
+	  const ptrdiff_t _Num = __last - __first;
+	  if (_Num)
+	    __builtin_memmove(__result, __first, sizeof(_Tp) * _Num);
+	  return __result + _Num;
+	}
+    };
+
+_GLIBCXX_BEGIN_NAMESPACE_CONTAINER
+
+  template<typename _Tp, typename _Ref, typename _Ptr>
+    struct _Deque_iterator;
+
+  struct _Bit_iterator;
+
+_GLIBCXX_END_NAMESPACE_CONTAINER
+
+  // Helpers for streambuf iterators (either istream or ostream).
+  // NB: avoid including <iosfwd>, relatively large.
+  template<typename _CharT>
+    struct char_traits;
+
+  template<typename _CharT, typename _Traits>
+    class istreambuf_iterator;
+
+  template<typename _CharT, typename _Traits>
+    class ostreambuf_iterator;
+
+  template<bool _IsMove, typename _CharT>
+    typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
+	     ostreambuf_iterator<_CharT, char_traits<_CharT> > >::__type
+    __copy_move_a2(_CharT*, _CharT*,
+		   ostreambuf_iterator<_CharT, char_traits<_CharT> >);
+
+  template<bool _IsMove, typename _CharT>
+    typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
+	     ostreambuf_iterator<_CharT, char_traits<_CharT> > >::__type
+    __copy_move_a2(const _CharT*, const _CharT*,
+		   ostreambuf_iterator<_CharT, char_traits<_CharT> >);
+
+  template<bool _IsMove, typename _CharT>
+    typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
+				    _CharT*>::__type
+    __copy_move_a2(istreambuf_iterator<_CharT, char_traits<_CharT> >,
+		   istreambuf_iterator<_CharT, char_traits<_CharT> >, _CharT*);
+
+  template<bool _IsMove, typename _CharT>
+    typename __gnu_cxx::__enable_if<
+      __is_char<_CharT>::__value,
+      _GLIBCXX_STD_C::_Deque_iterator<_CharT, _CharT&, _CharT*> >::__type
+    __copy_move_a2(
+	istreambuf_iterator<_CharT, char_traits<_CharT> >,
+	istreambuf_iterator<_CharT, char_traits<_CharT> >,
+	_GLIBCXX_STD_C::_Deque_iterator<_CharT, _CharT&, _CharT*>);
+
+  template<bool _IsMove, typename _II, typename _OI>
+    _GLIBCXX20_CONSTEXPR
+    inline _OI
+    __copy_move_a2(_II __first, _II __last, _OI __result)
+    {
+      typedef typename iterator_traits<_II>::iterator_category _Category;
+#ifdef __cpp_lib_is_constant_evaluated
+      if (std::is_constant_evaluated())
+	return std::__copy_move<_IsMove, false, _Category>::
+	  __copy_m(__first, __last, __result);
+#endif
+      return std::__copy_move<_IsMove, __memcpyable<_OI, _II>::__value,
+			      _Category>::__copy_m(__first, __last, __result);
+    }
+
+  template<bool _IsMove,
+	   typename _Tp, typename _Ref, typename _Ptr, typename _OI>
+    _OI
+    __copy_move_a1(_GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr>,
+		   _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr>,
+		   _OI);
+
+  template<bool _IsMove,
+	   typename _ITp, typename _IRef, typename _IPtr, typename _OTp>
+    _GLIBCXX_STD_C::_Deque_iterator<_OTp, _OTp&, _OTp*>
+    __copy_move_a1(_GLIBCXX_STD_C::_Deque_iterator<_ITp, _IRef, _IPtr>,
+		   _GLIBCXX_STD_C::_Deque_iterator<_ITp, _IRef, _IPtr>,
+		   _GLIBCXX_STD_C::_Deque_iterator<_OTp, _OTp&, _OTp*>);
+
+  template<bool _IsMove, typename _II, typename _Tp>
+    typename __gnu_cxx::__enable_if<
+      __is_random_access_iter<_II>::__value,
+      _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Tp&, _Tp*> >::__type
+    __copy_move_a1(_II, _II, _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Tp&, _Tp*>);
+
+  template<bool _IsMove, typename _II, typename _OI>
+    _GLIBCXX20_CONSTEXPR
+    inline _OI
+    __copy_move_a1(_II __first, _II __last, _OI __result)
+    { return std::__copy_move_a2<_IsMove>(__first, __last, __result); }
+
+  template<bool _IsMove, typename _II, typename _OI>
+    _GLIBCXX20_CONSTEXPR
+    inline _OI
+    __copy_move_a(_II __first, _II __last, _OI __result)
+    {
+      return std::__niter_wrap(__result,
+		std::__copy_move_a1<_IsMove>(std::__niter_base(__first),
+					     std::__niter_base(__last),
+					     std::__niter_base(__result)));
+    }
+
+  template<bool _IsMove,
+	   typename _Ite, typename _Seq, typename _Cat, typename _OI>
+    _OI
+    __copy_move_a(const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>&,
+		  const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>&,
+		  _OI);
+
+  template<bool _IsMove,
+	   typename _II, typename _Ite, typename _Seq, typename _Cat>
+    __gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>
+    __copy_move_a(_II, _II,
+		  const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>&);
+
+  template<bool _IsMove,
+	   typename _IIte, typename _ISeq, typename _ICat,
+	   typename _OIte, typename _OSeq, typename _OCat>
+    ::__gnu_debug::_Safe_iterator<_OIte, _OSeq, _OCat>
+    __copy_move_a(const ::__gnu_debug::_Safe_iterator<_IIte, _ISeq, _ICat>&,
+		  const ::__gnu_debug::_Safe_iterator<_IIte, _ISeq, _ICat>&,
+		  const ::__gnu_debug::_Safe_iterator<_OIte, _OSeq, _OCat>&);
+
+  template<typename _InputIterator, typename _Size, typename _OutputIterator>
+    _GLIBCXX20_CONSTEXPR
+    _OutputIterator
+    __copy_n_a(_InputIterator __first, _Size __n, _OutputIterator __result,
+	       bool)
+    {
+      if (__n > 0)
+	{
+	  while (true)
+	    {
+	      *__result = *__first;
+	      ++__result;
+	      if (--__n > 0)
+		++__first;
+	      else
+		break;
+	    }
+	}
+      return __result;
+    }
+
+  template<typename _CharT, typename _Size>
+    typename __gnu_cxx::__enable_if<
+      __is_char<_CharT>::__value, _CharT*>::__type
+    __copy_n_a(istreambuf_iterator<_CharT, char_traits<_CharT> >,
+	       _Size, _CharT*, bool);
+
+  template<typename _CharT, typename _Size>
+    typename __gnu_cxx::__enable_if<
+      __is_char<_CharT>::__value,
+      _GLIBCXX_STD_C::_Deque_iterator<_CharT, _CharT&, _CharT*> >::__type
+    __copy_n_a(istreambuf_iterator<_CharT, char_traits<_CharT> >, _Size,
+	       _GLIBCXX_STD_C::_Deque_iterator<_CharT, _CharT&, _CharT*>,
+	       bool);
+
+  /**
+   *  @brief Copies the range [first,last) into result.
+   *  @ingroup mutating_algorithms
+   *  @param  __first  An input iterator.
+   *  @param  __last   An input iterator.
+   *  @param  __result An output iterator.
+   *  @return   result + (last - first)
+   *
+   *  This inline function will boil down to a call to @c memmove whenever
+   *  possible.  Failing that, if random access iterators are passed, then the
+   *  loop count will be known (and therefore a candidate for compiler
+   *  optimizations such as unrolling).  Result may not be contained within
+   *  [first,last); the copy_backward function should be used instead.
+   *
+   *  Note that the end of the output range is permitted to be contained
+   *  within [first,last).
+  */
+  template<typename _II, typename _OI>
+    _GLIBCXX20_CONSTEXPR
+    inline _OI
+    copy(_II __first, _II __last, _OI __result)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_II>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OI,
+	    typename iterator_traits<_II>::reference>)
+      __glibcxx_requires_can_increment_range(__first, __last, __result);
+
+      return std::__copy_move_a<__is_move_iterator<_II>::__value>
+	     (std::__miter_base(__first), std::__miter_base(__last), __result);
+    }
+
+#if __cplusplus >= 201103L
+  /**
+   *  @brief Moves the range [first,last) into result.
+   *  @ingroup mutating_algorithms
+   *  @param  __first  An input iterator.
+   *  @param  __last   An input iterator.
+   *  @param  __result An output iterator.
+   *  @return   result + (last - first)
+   *
+   *  This inline function will boil down to a call to @c memmove whenever
+   *  possible.  Failing that, if random access iterators are passed, then the
+   *  loop count will be known (and therefore a candidate for compiler
+   *  optimizations such as unrolling).  Result may not be contained within
+   *  [first,last); the move_backward function should be used instead.
+   *
+   *  Note that the end of the output range is permitted to be contained
+   *  within [first,last).
+  */
+  template<typename _II, typename _OI>
+    _GLIBCXX20_CONSTEXPR
+    inline _OI
+    move(_II __first, _II __last, _OI __result)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_II>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OI,
+	    typename iterator_traits<_II>::value_type&&>)
+      __glibcxx_requires_can_increment_range(__first, __last, __result);
+
+      return std::__copy_move_a<true>(std::__miter_base(__first),
+				      std::__miter_base(__last), __result);
+    }
+
+#define _GLIBCXX_MOVE3(_Tp, _Up, _Vp) std::move(_Tp, _Up, _Vp)
+#else
+#define _GLIBCXX_MOVE3(_Tp, _Up, _Vp) std::copy(_Tp, _Up, _Vp)
+#endif
+
+  template<bool _IsMove, bool _IsSimple, typename _Category>
+    struct __copy_move_backward
+    {
+      template<typename _BI1, typename _BI2>
+	_GLIBCXX20_CONSTEXPR
+	static _BI2
+	__copy_move_b(_BI1 __first, _BI1 __last, _BI2 __result)
+	{
+	  while (__first != __last)
+	    *--__result = *--__last;
+	  return __result;
+	}
+    };
+
+#if __cplusplus >= 201103L
+  template<typename _Category>
+    struct __copy_move_backward<true, false, _Category>
+    {
+      template<typename _BI1, typename _BI2>
+	_GLIBCXX20_CONSTEXPR
+	static _BI2
+	__copy_move_b(_BI1 __first, _BI1 __last, _BI2 __result)
+	{
+	  while (__first != __last)
+	    *--__result = std::move(*--__last);
+	  return __result;
+	}
+    };
+#endif
+
+  template<>
+    struct __copy_move_backward<false, false, random_access_iterator_tag>
+    {
+      template<typename _BI1, typename _BI2>
+	_GLIBCXX20_CONSTEXPR
+	static _BI2
+	__copy_move_b(_BI1 __first, _BI1 __last, _BI2 __result)
+	{
+	  typename iterator_traits<_BI1>::difference_type
+	    __n = __last - __first;
+	  for (; __n > 0; --__n)
+	    *--__result = *--__last;
+	  return __result;
+	}
+    };
+
+#if __cplusplus >= 201103L
+  template<>
+    struct __copy_move_backward<true, false, random_access_iterator_tag>
+    {
+      template<typename _BI1, typename _BI2>
+	_GLIBCXX20_CONSTEXPR
+	static _BI2
+	__copy_move_b(_BI1 __first, _BI1 __last, _BI2 __result)
+	{
+	  typename iterator_traits<_BI1>::difference_type
+	    __n = __last - __first;
+	  for (; __n > 0; --__n)
+	    *--__result = std::move(*--__last);
+	  return __result;
+	}
+    };
+#endif
+
+  template<bool _IsMove>
+    struct __copy_move_backward<_IsMove, true, random_access_iterator_tag>
+    {
+      template<typename _Tp>
+	_GLIBCXX20_CONSTEXPR
+	static _Tp*
+	__copy_move_b(const _Tp* __first, const _Tp* __last, _Tp* __result)
+	{
+#if __cplusplus >= 201103L
+	  using __assignable = __conditional_t<_IsMove,
+					       is_move_assignable<_Tp>,
+					       is_copy_assignable<_Tp>>;
+	  // trivial types can have deleted assignment
+	  static_assert( __assignable::value, "type must be assignable" );
+#endif
+	  const ptrdiff_t _Num = __last - __first;
+	  if (_Num)
+	    __builtin_memmove(__result - _Num, __first, sizeof(_Tp) * _Num);
+	  return __result - _Num;
+	}
+    };
+
+  template<bool _IsMove, typename _BI1, typename _BI2>
+    _GLIBCXX20_CONSTEXPR
+    inline _BI2
+    __copy_move_backward_a2(_BI1 __first, _BI1 __last, _BI2 __result)
+    {
+      typedef typename iterator_traits<_BI1>::iterator_category _Category;
+#ifdef __cpp_lib_is_constant_evaluated
+      if (std::is_constant_evaluated())
+	return std::__copy_move_backward<_IsMove, false, _Category>::
+	  __copy_move_b(__first, __last, __result);
+#endif
+      return std::__copy_move_backward<_IsMove,
+				       __memcpyable<_BI2, _BI1>::__value,
+				       _Category>::__copy_move_b(__first,
+								 __last,
+								 __result);
+    }
+
+  template<bool _IsMove, typename _BI1, typename _BI2>
+    _GLIBCXX20_CONSTEXPR
+    inline _BI2
+    __copy_move_backward_a1(_BI1 __first, _BI1 __last, _BI2 __result)
+    { return std::__copy_move_backward_a2<_IsMove>(__first, __last, __result); }
+
+  template<bool _IsMove,
+	   typename _Tp, typename _Ref, typename _Ptr, typename _OI>
+    _OI
+    __copy_move_backward_a1(_GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr>,
+			    _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr>,
+			    _OI);
+
+  template<bool _IsMove,
+	   typename _ITp, typename _IRef, typename _IPtr, typename _OTp>
+    _GLIBCXX_STD_C::_Deque_iterator<_OTp, _OTp&, _OTp*>
+    __copy_move_backward_a1(
+			_GLIBCXX_STD_C::_Deque_iterator<_ITp, _IRef, _IPtr>,
+			_GLIBCXX_STD_C::_Deque_iterator<_ITp, _IRef, _IPtr>,
+			_GLIBCXX_STD_C::_Deque_iterator<_OTp, _OTp&, _OTp*>);
+
+  template<bool _IsMove, typename _II, typename _Tp>
+    typename __gnu_cxx::__enable_if<
+      __is_random_access_iter<_II>::__value,
+      _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Tp&, _Tp*> >::__type
+    __copy_move_backward_a1(_II, _II,
+			    _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Tp&, _Tp*>);
+
+  template<bool _IsMove, typename _II, typename _OI>
+    _GLIBCXX20_CONSTEXPR
+    inline _OI
+    __copy_move_backward_a(_II __first, _II __last, _OI __result)
+    {
+      return std::__niter_wrap(__result,
+		std::__copy_move_backward_a1<_IsMove>
+		  (std::__niter_base(__first), std::__niter_base(__last),
+		   std::__niter_base(__result)));
+    }
+
+  template<bool _IsMove,
+	   typename _Ite, typename _Seq, typename _Cat, typename _OI>
+    _OI
+    __copy_move_backward_a(
+		const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>&,
+		const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>&,
+		_OI);
+
+  template<bool _IsMove,
+	   typename _II, typename _Ite, typename _Seq, typename _Cat>
+    __gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>
+    __copy_move_backward_a(_II, _II,
+		const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>&);
+
+  template<bool _IsMove,
+	   typename _IIte, typename _ISeq, typename _ICat,
+	   typename _OIte, typename _OSeq, typename _OCat>
+    ::__gnu_debug::_Safe_iterator<_OIte, _OSeq, _OCat>
+    __copy_move_backward_a(
+		const ::__gnu_debug::_Safe_iterator<_IIte, _ISeq, _ICat>&,
+		const ::__gnu_debug::_Safe_iterator<_IIte, _ISeq, _ICat>&,
+		const ::__gnu_debug::_Safe_iterator<_OIte, _OSeq, _OCat>&);
+
+  /**
+   *  @brief Copies the range [first,last) into result.
+   *  @ingroup mutating_algorithms
+   *  @param  __first  A bidirectional iterator.
+   *  @param  __last   A bidirectional iterator.
+   *  @param  __result A bidirectional iterator.
+   *  @return   result - (last - first)
+   *
+   *  The function has the same effect as copy, but starts at the end of the
+   *  range and works its way to the start, returning the start of the result.
+   *  This inline function will boil down to a call to @c memmove whenever
+   *  possible.  Failing that, if random access iterators are passed, then the
+   *  loop count will be known (and therefore a candidate for compiler
+   *  optimizations such as unrolling).
+   *
+   *  Result may not be in the range (first,last].  Use copy instead.  Note
+   *  that the start of the output range may overlap [first,last).
+  */
+  template<typename _BI1, typename _BI2>
+    _GLIBCXX20_CONSTEXPR
+    inline _BI2
+    copy_backward(_BI1 __first, _BI1 __last, _BI2 __result)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_BidirectionalIteratorConcept<_BI1>)
+      __glibcxx_function_requires(_Mutable_BidirectionalIteratorConcept<_BI2>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_BI2,
+	    typename iterator_traits<_BI1>::reference>)
+      __glibcxx_requires_can_decrement_range(__first, __last, __result);
+
+      return std::__copy_move_backward_a<__is_move_iterator<_BI1>::__value>
+	     (std::__miter_base(__first), std::__miter_base(__last), __result);
+    }
+
+#if __cplusplus >= 201103L
+  /**
+   *  @brief Moves the range [first,last) into result.
+   *  @ingroup mutating_algorithms
+   *  @param  __first  A bidirectional iterator.
+   *  @param  __last   A bidirectional iterator.
+   *  @param  __result A bidirectional iterator.
+   *  @return   result - (last - first)
+   *
+   *  The function has the same effect as move, but starts at the end of the
+   *  range and works its way to the start, returning the start of the result.
+   *  This inline function will boil down to a call to @c memmove whenever
+   *  possible.  Failing that, if random access iterators are passed, then the
+   *  loop count will be known (and therefore a candidate for compiler
+   *  optimizations such as unrolling).
+   *
+   *  Result may not be in the range (first,last].  Use move instead.  Note
+   *  that the start of the output range may overlap [first,last).
+  */
+  template<typename _BI1, typename _BI2>
+    _GLIBCXX20_CONSTEXPR
+    inline _BI2
+    move_backward(_BI1 __first, _BI1 __last, _BI2 __result)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_BidirectionalIteratorConcept<_BI1>)
+      __glibcxx_function_requires(_Mutable_BidirectionalIteratorConcept<_BI2>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_BI2,
+	    typename iterator_traits<_BI1>::value_type&&>)
+      __glibcxx_requires_can_decrement_range(__first, __last, __result);
+
+      return std::__copy_move_backward_a<true>(std::__miter_base(__first),
+					       std::__miter_base(__last),
+					       __result);
+    }
+
+#define _GLIBCXX_MOVE_BACKWARD3(_Tp, _Up, _Vp) std::move_backward(_Tp, _Up, _Vp)
+#else
+#define _GLIBCXX_MOVE_BACKWARD3(_Tp, _Up, _Vp) std::copy_backward(_Tp, _Up, _Vp)
+#endif
+
+  template<typename _ForwardIterator, typename _Tp>
+    _GLIBCXX20_CONSTEXPR
+    inline typename
+    __gnu_cxx::__enable_if<!__is_scalar<_Tp>::__value, void>::__type
+    __fill_a1(_ForwardIterator __first, _ForwardIterator __last,
+	      const _Tp& __value)
+    {
+      for (; __first != __last; ++__first)
+	*__first = __value;
+    }
+
+  template<typename _ForwardIterator, typename _Tp>
+    _GLIBCXX20_CONSTEXPR
+    inline typename
+    __gnu_cxx::__enable_if<__is_scalar<_Tp>::__value, void>::__type
+    __fill_a1(_ForwardIterator __first, _ForwardIterator __last,
+	      const _Tp& __value)
+    {
+      const _Tp __tmp = __value;
+      for (; __first != __last; ++__first)
+	*__first = __tmp;
+    }
+
+  // Specialization: for char types we can use memset.
+  template<typename _Tp>
+    _GLIBCXX20_CONSTEXPR
+    inline typename
+    __gnu_cxx::__enable_if<__is_byte<_Tp>::__value, void>::__type
+    __fill_a1(_Tp* __first, _Tp* __last, const _Tp& __c)
+    {
+      const _Tp __tmp = __c;
+#if __cpp_lib_is_constant_evaluated
+      if (std::is_constant_evaluated())
+	{
+	  for (; __first != __last; ++__first)
+	    *__first = __tmp;
+	  return;
+	}
+#endif
+      if (const size_t __len = __last - __first)
+	__builtin_memset(__first, static_cast<unsigned char>(__tmp), __len);
+    }
+
+  template<typename _Ite, typename _Cont, typename _Tp>
+    _GLIBCXX20_CONSTEXPR
+    inline void
+    __fill_a1(::__gnu_cxx::__normal_iterator<_Ite, _Cont> __first,
+	      ::__gnu_cxx::__normal_iterator<_Ite, _Cont> __last,
+	      const _Tp& __value)
+    { std::__fill_a1(__first.base(), __last.base(), __value); }
+
+  template<typename _Tp, typename _VTp>
+    void
+    __fill_a1(const _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Tp&, _Tp*>&,
+	      const _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Tp&, _Tp*>&,
+	      const _VTp&);
+
+  _GLIBCXX20_CONSTEXPR
+  void
+  __fill_a1(_GLIBCXX_STD_C::_Bit_iterator, _GLIBCXX_STD_C::_Bit_iterator,
+	    const bool&);
+
+  template<typename _FIte, typename _Tp>
+    _GLIBCXX20_CONSTEXPR
+    inline void
+    __fill_a(_FIte __first, _FIte __last, const _Tp& __value)
+    { std::__fill_a1(__first, __last, __value); }
+
+  template<typename _Ite, typename _Seq, typename _Cat, typename _Tp>
+    void
+    __fill_a(const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>&,
+	     const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>&,
+	     const _Tp&);
+
+  /**
+   *  @brief Fills the range [first,last) with copies of value.
+   *  @ingroup mutating_algorithms
+   *  @param  __first  A forward iterator.
+   *  @param  __last   A forward iterator.
+   *  @param  __value  A reference-to-const of arbitrary type.
+   *  @return   Nothing.
+   *
+   *  This function fills a range with copies of the same value.  For char
+   *  types filling contiguous areas of memory, this becomes an inline call
+   *  to @c memset or @c wmemset.
+  */
+  template<typename _ForwardIterator, typename _Tp>
+    _GLIBCXX20_CONSTEXPR
+    inline void
+    fill(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
+				  _ForwardIterator>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      std::__fill_a(__first, __last, __value);
+    }
+
+  // Used by fill_n, generate_n, etc. to convert _Size to an integral type:
+  inline _GLIBCXX_CONSTEXPR int
+  __size_to_integer(int __n) { return __n; }
+  inline _GLIBCXX_CONSTEXPR unsigned
+  __size_to_integer(unsigned __n) { return __n; }
+  inline _GLIBCXX_CONSTEXPR long
+  __size_to_integer(long __n) { return __n; }
+  inline _GLIBCXX_CONSTEXPR unsigned long
+  __size_to_integer(unsigned long __n) { return __n; }
+  inline _GLIBCXX_CONSTEXPR long long
+  __size_to_integer(long long __n) { return __n; }
+  inline _GLIBCXX_CONSTEXPR unsigned long long
+  __size_to_integer(unsigned long long __n) { return __n; }
+
+#if defined(__GLIBCXX_TYPE_INT_N_0)
+  __extension__ inline _GLIBCXX_CONSTEXPR __GLIBCXX_TYPE_INT_N_0
+  __size_to_integer(__GLIBCXX_TYPE_INT_N_0 __n) { return __n; }
+  __extension__ inline _GLIBCXX_CONSTEXPR unsigned __GLIBCXX_TYPE_INT_N_0
+  __size_to_integer(unsigned __GLIBCXX_TYPE_INT_N_0 __n) { return __n; }
+#endif
+#if defined(__GLIBCXX_TYPE_INT_N_1)
+  __extension__ inline _GLIBCXX_CONSTEXPR __GLIBCXX_TYPE_INT_N_1
+  __size_to_integer(__GLIBCXX_TYPE_INT_N_1 __n) { return __n; }
+  __extension__ inline _GLIBCXX_CONSTEXPR unsigned __GLIBCXX_TYPE_INT_N_1
+  __size_to_integer(unsigned __GLIBCXX_TYPE_INT_N_1 __n) { return __n; }
+#endif
+#if defined(__GLIBCXX_TYPE_INT_N_2)
+  __extension__ inline _GLIBCXX_CONSTEXPR __GLIBCXX_TYPE_INT_N_2
+  __size_to_integer(__GLIBCXX_TYPE_INT_N_2 __n) { return __n; }
+  __extension__ inline _GLIBCXX_CONSTEXPR unsigned __GLIBCXX_TYPE_INT_N_2
+  __size_to_integer(unsigned __GLIBCXX_TYPE_INT_N_2 __n) { return __n; }
+#endif
+#if defined(__GLIBCXX_TYPE_INT_N_3)
+  __extension__ inline _GLIBCXX_CONSTEXPR unsigned __GLIBCXX_TYPE_INT_N_3
+  __size_to_integer(__GLIBCXX_TYPE_INT_N_3 __n) { return __n; }
+  __extension__ inline _GLIBCXX_CONSTEXPR __GLIBCXX_TYPE_INT_N_3
+  __size_to_integer(unsigned __GLIBCXX_TYPE_INT_N_3 __n) { return __n; }
+#endif
+
+  inline _GLIBCXX_CONSTEXPR long long
+  __size_to_integer(float __n) { return (long long)__n; }
+  inline _GLIBCXX_CONSTEXPR long long
+  __size_to_integer(double __n) { return (long long)__n; }
+  inline _GLIBCXX_CONSTEXPR long long
+  __size_to_integer(long double __n) { return (long long)__n; }
+#if !defined(__STRICT_ANSI__) && defined(_GLIBCXX_USE_FLOAT128)
+  __extension__ inline _GLIBCXX_CONSTEXPR long long
+  __size_to_integer(__float128 __n) { return (long long)__n; }
+#endif
+
+  template<typename _OutputIterator, typename _Size, typename _Tp>
+    _GLIBCXX20_CONSTEXPR
+    inline typename
+    __gnu_cxx::__enable_if<!__is_scalar<_Tp>::__value, _OutputIterator>::__type
+    __fill_n_a1(_OutputIterator __first, _Size __n, const _Tp& __value)
+    {
+      for (; __n > 0; --__n, (void) ++__first)
+	*__first = __value;
+      return __first;
+    }
+
+  template<typename _OutputIterator, typename _Size, typename _Tp>
+    _GLIBCXX20_CONSTEXPR
+    inline typename
+    __gnu_cxx::__enable_if<__is_scalar<_Tp>::__value, _OutputIterator>::__type
+    __fill_n_a1(_OutputIterator __first, _Size __n, const _Tp& __value)
+    {
+      const _Tp __tmp = __value;
+      for (; __n > 0; --__n, (void) ++__first)
+	*__first = __tmp;
+      return __first;
+    }
+
+  template<typename _Ite, typename _Seq, typename _Cat, typename _Size,
+	   typename _Tp>
+    ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>
+    __fill_n_a(const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>& __first,
+	       _Size __n, const _Tp& __value,
+	       std::input_iterator_tag);
+
+  template<typename _OutputIterator, typename _Size, typename _Tp>
+    _GLIBCXX20_CONSTEXPR
+    inline _OutputIterator
+    __fill_n_a(_OutputIterator __first, _Size __n, const _Tp& __value,
+	       std::output_iterator_tag)
+    {
+#if __cplusplus >= 201103L
+      static_assert(is_integral<_Size>{}, "fill_n must pass integral size");
+#endif
+      return __fill_n_a1(__first, __n, __value);
+    }
+
+  template<typename _OutputIterator, typename _Size, typename _Tp>
+    _GLIBCXX20_CONSTEXPR
+    inline _OutputIterator
+    __fill_n_a(_OutputIterator __first, _Size __n, const _Tp& __value,
+	       std::input_iterator_tag)
+    {
+#if __cplusplus >= 201103L
+      static_assert(is_integral<_Size>{}, "fill_n must pass integral size");
+#endif
+      return __fill_n_a1(__first, __n, __value);
+    }
+
+  template<typename _OutputIterator, typename _Size, typename _Tp>
+    _GLIBCXX20_CONSTEXPR
+    inline _OutputIterator
+    __fill_n_a(_OutputIterator __first, _Size __n, const _Tp& __value,
+	       std::random_access_iterator_tag)
+    {
+#if __cplusplus >= 201103L
+      static_assert(is_integral<_Size>{}, "fill_n must pass integral size");
+#endif
+      if (__n <= 0)
+	return __first;
+
+      __glibcxx_requires_can_increment(__first, __n);
+
+      std::__fill_a(__first, __first + __n, __value);
+      return __first + __n;
+    }
+
+  /**
+   *  @brief Fills the range [first,first+n) with copies of value.
+   *  @ingroup mutating_algorithms
+   *  @param  __first  An output iterator.
+   *  @param  __n      The count of copies to perform.
+   *  @param  __value  A reference-to-const of arbitrary type.
+   *  @return   The iterator at first+n.
+   *
+   *  This function fills a range with copies of the same value.  For char
+   *  types filling contiguous areas of memory, this becomes an inline call
+   *  to @c memset or @c wmemset.
+   *
+   *  If @p __n is negative, the function does nothing.
+  */
+  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+  // DR 865. More algorithms that throw away information
+  // DR 426. search_n(), fill_n(), and generate_n() with negative n
+  template<typename _OI, typename _Size, typename _Tp>
+    _GLIBCXX20_CONSTEXPR
+    inline _OI
+    fill_n(_OI __first, _Size __n, const _Tp& __value)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_OutputIteratorConcept<_OI, const _Tp&>)
+
+      return std::__fill_n_a(__first, std::__size_to_integer(__n), __value,
+			       std::__iterator_category(__first));
+    }
+
+  template<bool _BoolType>
+    struct __equal
+    {
+      template<typename _II1, typename _II2>
+	_GLIBCXX20_CONSTEXPR
+	static bool
+	equal(_II1 __first1, _II1 __last1, _II2 __first2)
+	{
+	  for (; __first1 != __last1; ++__first1, (void) ++__first2)
+	    if (!(*__first1 == *__first2))
+	      return false;
+	  return true;
+	}
+    };
+
+  template<>
+    struct __equal<true>
+    {
+      template<typename _Tp>
+	_GLIBCXX20_CONSTEXPR
+	static bool
+	equal(const _Tp* __first1, const _Tp* __last1, const _Tp* __first2)
+	{
+	  if (const size_t __len = (__last1 - __first1))
+	    return !std::__memcmp(__first1, __first2, __len);
+	  return true;
+	}
+    };
+
+  template<typename _Tp, typename _Ref, typename _Ptr, typename _II>
+    typename __gnu_cxx::__enable_if<
+      __is_random_access_iter<_II>::__value, bool>::__type
+    __equal_aux1(_GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr>,
+		 _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr>,
+		 _II);
+
+  template<typename _Tp1, typename _Ref1, typename _Ptr1,
+	   typename _Tp2, typename _Ref2, typename _Ptr2>
+    bool
+    __equal_aux1(_GLIBCXX_STD_C::_Deque_iterator<_Tp1, _Ref1, _Ptr1>,
+		 _GLIBCXX_STD_C::_Deque_iterator<_Tp1, _Ref1, _Ptr1>,
+		 _GLIBCXX_STD_C::_Deque_iterator<_Tp2, _Ref2, _Ptr2>);
+
+  template<typename _II, typename _Tp, typename _Ref, typename _Ptr>
+    typename __gnu_cxx::__enable_if<
+      __is_random_access_iter<_II>::__value, bool>::__type
+    __equal_aux1(_II, _II,
+		_GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr>);
+
+  template<typename _II1, typename _II2>
+    _GLIBCXX20_CONSTEXPR
+    inline bool
+    __equal_aux1(_II1 __first1, _II1 __last1, _II2 __first2)
+    {
+      typedef typename iterator_traits<_II1>::value_type _ValueType1;
+      const bool __simple = ((__is_integer<_ValueType1>::__value
+			      || __is_pointer<_ValueType1>::__value)
+			     && __memcmpable<_II1, _II2>::__value);
+      return std::__equal<__simple>::equal(__first1, __last1, __first2);
+    }
+
+  template<typename _II1, typename _II2>
+    _GLIBCXX20_CONSTEXPR
+    inline bool
+    __equal_aux(_II1 __first1, _II1 __last1, _II2 __first2)
+    {
+      return std::__equal_aux1(std::__niter_base(__first1),
+			       std::__niter_base(__last1),
+			       std::__niter_base(__first2));
+    }
+
+  template<typename _II1, typename _Seq1, typename _Cat1, typename _II2>
+    bool
+    __equal_aux(const ::__gnu_debug::_Safe_iterator<_II1, _Seq1, _Cat1>&,
+		const ::__gnu_debug::_Safe_iterator<_II1, _Seq1, _Cat1>&,
+		_II2);
+
+  template<typename _II1, typename _II2, typename _Seq2, typename _Cat2>
+    bool
+    __equal_aux(_II1, _II1,
+		const ::__gnu_debug::_Safe_iterator<_II2, _Seq2, _Cat2>&);
+
+  template<typename _II1, typename _Seq1, typename _Cat1,
+	   typename _II2, typename _Seq2, typename _Cat2>
+    bool
+    __equal_aux(const ::__gnu_debug::_Safe_iterator<_II1, _Seq1, _Cat1>&,
+		const ::__gnu_debug::_Safe_iterator<_II1, _Seq1, _Cat1>&,
+		const ::__gnu_debug::_Safe_iterator<_II2, _Seq2, _Cat2>&);
+
+  template<typename, typename>
+    struct __lc_rai
+    {
+      template<typename _II1, typename _II2>
+	_GLIBCXX20_CONSTEXPR
+	static _II1
+	__newlast1(_II1, _II1 __last1, _II2, _II2)
+	{ return __last1; }
+
+      template<typename _II>
+	_GLIBCXX20_CONSTEXPR
+	static bool
+	__cnd2(_II __first, _II __last)
+	{ return __first != __last; }
+    };
+
+  template<>
+    struct __lc_rai<random_access_iterator_tag, random_access_iterator_tag>
+    {
+      template<typename _RAI1, typename _RAI2>
+	_GLIBCXX20_CONSTEXPR
+	static _RAI1
+	__newlast1(_RAI1 __first1, _RAI1 __last1,
+		   _RAI2 __first2, _RAI2 __last2)
+	{
+	  const typename iterator_traits<_RAI1>::difference_type
+	    __diff1 = __last1 - __first1;
+	  const typename iterator_traits<_RAI2>::difference_type
+	    __diff2 = __last2 - __first2;
+	  return __diff2 < __diff1 ? __first1 + __diff2 : __last1;
+	}
+
+      template<typename _RAI>
+	static _GLIBCXX20_CONSTEXPR bool
+	__cnd2(_RAI, _RAI)
+	{ return true; }
+    };
+
+  template<typename _II1, typename _II2, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    bool
+    __lexicographical_compare_impl(_II1 __first1, _II1 __last1,
+				   _II2 __first2, _II2 __last2,
+				   _Compare __comp)
+    {
+      typedef typename iterator_traits<_II1>::iterator_category _Category1;
+      typedef typename iterator_traits<_II2>::iterator_category _Category2;
+      typedef std::__lc_rai<_Category1, _Category2> __rai_type;
+
+      __last1 = __rai_type::__newlast1(__first1, __last1, __first2, __last2);
+      for (; __first1 != __last1 && __rai_type::__cnd2(__first2, __last2);
+	   ++__first1, (void)++__first2)
+	{
+	  if (__comp(__first1, __first2))
+	    return true;
+	  if (__comp(__first2, __first1))
+	    return false;
+	}
+      return __first1 == __last1 && __first2 != __last2;
+    }
+
+  template<bool _BoolType>
+    struct __lexicographical_compare
+    {
+      template<typename _II1, typename _II2>
+	_GLIBCXX20_CONSTEXPR
+	static bool
+	__lc(_II1 __first1, _II1 __last1, _II2 __first2, _II2 __last2)
+	{
+	  using __gnu_cxx::__ops::__iter_less_iter;
+	  return std::__lexicographical_compare_impl(__first1, __last1,
+						     __first2, __last2,
+						     __iter_less_iter());
+	}
+
+      template<typename _II1, typename _II2>
+	_GLIBCXX20_CONSTEXPR
+	static int
+	__3way(_II1 __first1, _II1 __last1, _II2 __first2, _II2 __last2)
+	{
+	  while (__first1 != __last1)
+	    {
+	      if (__first2 == __last2)
+		return +1;
+	      if (*__first1 < *__first2)
+		return -1;
+	      if (*__first2 < *__first1)
+		return +1;
+	      ++__first1;
+	      ++__first2;
+	    }
+	  return int(__first2 == __last2) - 1;
+	}
+    };
+
+  template<>
+    struct __lexicographical_compare<true>
+    {
+      template<typename _Tp, typename _Up>
+	_GLIBCXX20_CONSTEXPR
+	static bool
+	__lc(const _Tp* __first1, const _Tp* __last1,
+	     const _Up* __first2, const _Up* __last2)
+	{ return __3way(__first1, __last1, __first2, __last2) < 0; }
+
+      template<typename _Tp, typename _Up>
+	_GLIBCXX20_CONSTEXPR
+	static ptrdiff_t
+	__3way(const _Tp* __first1, const _Tp* __last1,
+	       const _Up* __first2, const _Up* __last2)
+	{
+	  const size_t __len1 = __last1 - __first1;
+	  const size_t __len2 = __last2 - __first2;
+	  if (const size_t __len = std::min(__len1, __len2))
+	    if (int __result = std::__memcmp(__first1, __first2, __len))
+	      return __result;
+	  return ptrdiff_t(__len1 - __len2);
+	}
+    };
+
+  template<typename _II1, typename _II2>
+    _GLIBCXX20_CONSTEXPR
+    inline bool
+    __lexicographical_compare_aux1(_II1 __first1, _II1 __last1,
+				   _II2 __first2, _II2 __last2)
+    {
+      typedef typename iterator_traits<_II1>::value_type _ValueType1;
+      typedef typename iterator_traits<_II2>::value_type _ValueType2;
+      const bool __simple =
+	(__is_memcmp_ordered_with<_ValueType1, _ValueType2>::__value
+	 && __is_pointer<_II1>::__value
+	 && __is_pointer<_II2>::__value
+#if __cplusplus > 201703L && __cpp_lib_concepts
+	 // For C++20 iterator_traits<volatile T*>::value_type is non-volatile
+	 // so __is_byte<T> could be true, but we can't use memcmp with
+	 // volatile data.
+	 && !is_volatile_v<remove_reference_t<iter_reference_t<_II1>>>
+	 && !is_volatile_v<remove_reference_t<iter_reference_t<_II2>>>
+#endif
+	 );
+
+      return std::__lexicographical_compare<__simple>::__lc(__first1, __last1,
+							    __first2, __last2);
+    }
+
+  template<typename _Tp1, typename _Ref1, typename _Ptr1,
+	   typename _Tp2>
+    bool
+    __lexicographical_compare_aux1(
+	_GLIBCXX_STD_C::_Deque_iterator<_Tp1, _Ref1, _Ptr1>,
+	_GLIBCXX_STD_C::_Deque_iterator<_Tp1, _Ref1, _Ptr1>,
+	_Tp2*, _Tp2*);
+
+  template<typename _Tp1,
+	   typename _Tp2, typename _Ref2, typename _Ptr2>
+    bool
+    __lexicographical_compare_aux1(_Tp1*, _Tp1*,
+	_GLIBCXX_STD_C::_Deque_iterator<_Tp2, _Ref2, _Ptr2>,
+	_GLIBCXX_STD_C::_Deque_iterator<_Tp2, _Ref2, _Ptr2>);
+
+  template<typename _Tp1, typename _Ref1, typename _Ptr1,
+	   typename _Tp2, typename _Ref2, typename _Ptr2>
+    bool
+    __lexicographical_compare_aux1(
+	_GLIBCXX_STD_C::_Deque_iterator<_Tp1, _Ref1, _Ptr1>,
+	_GLIBCXX_STD_C::_Deque_iterator<_Tp1, _Ref1, _Ptr1>,
+	_GLIBCXX_STD_C::_Deque_iterator<_Tp2, _Ref2, _Ptr2>,
+	_GLIBCXX_STD_C::_Deque_iterator<_Tp2, _Ref2, _Ptr2>);
+
+  template<typename _II1, typename _II2>
+    _GLIBCXX20_CONSTEXPR
+    inline bool
+    __lexicographical_compare_aux(_II1 __first1, _II1 __last1,
+				  _II2 __first2, _II2 __last2)
+    {
+      return std::__lexicographical_compare_aux1(std::__niter_base(__first1),
+						 std::__niter_base(__last1),
+						 std::__niter_base(__first2),
+						 std::__niter_base(__last2));
+    }
+
+  template<typename _Iter1, typename _Seq1, typename _Cat1,
+	   typename _II2>
+    bool
+    __lexicographical_compare_aux(
+		const ::__gnu_debug::_Safe_iterator<_Iter1, _Seq1, _Cat1>&,
+		const ::__gnu_debug::_Safe_iterator<_Iter1, _Seq1, _Cat1>&,
+		_II2, _II2);
+
+  template<typename _II1,
+	   typename _Iter2, typename _Seq2, typename _Cat2>
+    bool
+    __lexicographical_compare_aux(
+		_II1, _II1,
+		const ::__gnu_debug::_Safe_iterator<_Iter2, _Seq2, _Cat2>&,
+		const ::__gnu_debug::_Safe_iterator<_Iter2, _Seq2, _Cat2>&);
+
+  template<typename _Iter1, typename _Seq1, typename _Cat1,
+	   typename _Iter2, typename _Seq2, typename _Cat2>
+    bool
+    __lexicographical_compare_aux(
+		const ::__gnu_debug::_Safe_iterator<_Iter1, _Seq1, _Cat1>&,
+		const ::__gnu_debug::_Safe_iterator<_Iter1, _Seq1, _Cat1>&,
+		const ::__gnu_debug::_Safe_iterator<_Iter2, _Seq2, _Cat2>&,
+		const ::__gnu_debug::_Safe_iterator<_Iter2, _Seq2, _Cat2>&);
+
+  template<typename _ForwardIterator, typename _Tp, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    _ForwardIterator
+    __lower_bound(_ForwardIterator __first, _ForwardIterator __last,
+		  const _Tp& __val, _Compare __comp)
+    {
+      typedef typename iterator_traits<_ForwardIterator>::difference_type
+	_DistanceType;
+
+      _DistanceType __len = std::distance(__first, __last);
+
+      while (__len > 0)
+	{
+	  _DistanceType __half = __len >> 1;
+	  _ForwardIterator __middle = __first;
+	  std::advance(__middle, __half);
+	  if (__comp(__middle, __val))
+	    {
+	      __first = __middle;
+	      ++__first;
+	      __len = __len - __half - 1;
+	    }
+	  else
+	    __len = __half;
+	}
+      return __first;
+    }
+
+  /**
+   *  @brief Finds the first position in which @a val could be inserted
+   *         without changing the ordering.
+   *  @param  __first   An iterator.
+   *  @param  __last    Another iterator.
+   *  @param  __val     The search term.
+   *  @return         An iterator pointing to the first element <em>not less
+   *                  than</em> @a val, or end() if every element is less than
+   *                  @a val.
+   *  @ingroup binary_search_algorithms
+  */
+  template<typename _ForwardIterator, typename _Tp>
+    _GLIBCXX20_CONSTEXPR
+    inline _ForwardIterator
+    lower_bound(_ForwardIterator __first, _ForwardIterator __last,
+		const _Tp& __val)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+      __glibcxx_function_requires(_LessThanOpConcept<
+	    typename iterator_traits<_ForwardIterator>::value_type, _Tp>)
+      __glibcxx_requires_partitioned_lower(__first, __last, __val);
+
+      return std::__lower_bound(__first, __last, __val,
+				__gnu_cxx::__ops::__iter_less_val());
+    }
+
+  /// This is a helper function for the sort routines and for random.tcc.
+  //  Precondition: __n > 0.
+  inline _GLIBCXX_CONSTEXPR int
+  __lg(int __n)
+  { return (int)sizeof(int) * __CHAR_BIT__  - 1 - __builtin_clz(__n); }
+
+  inline _GLIBCXX_CONSTEXPR unsigned
+  __lg(unsigned __n)
+  { return (int)sizeof(int) * __CHAR_BIT__  - 1 - __builtin_clz(__n); }
+
+  inline _GLIBCXX_CONSTEXPR long
+  __lg(long __n)
+  { return (int)sizeof(long) * __CHAR_BIT__ - 1 - __builtin_clzl(__n); }
+
+  inline _GLIBCXX_CONSTEXPR unsigned long
+  __lg(unsigned long __n)
+  { return (int)sizeof(long) * __CHAR_BIT__ - 1 - __builtin_clzl(__n); }
+
+  inline _GLIBCXX_CONSTEXPR long long
+  __lg(long long __n)
+  { return (int)sizeof(long long) * __CHAR_BIT__ - 1 - __builtin_clzll(__n); }
+
+  inline _GLIBCXX_CONSTEXPR unsigned long long
+  __lg(unsigned long long __n)
+  { return (int)sizeof(long long) * __CHAR_BIT__ - 1 - __builtin_clzll(__n); }
+
+_GLIBCXX_BEGIN_NAMESPACE_ALGO
+
+  /**
+   *  @brief Tests a range for element-wise equality.
+   *  @ingroup non_mutating_algorithms
+   *  @param  __first1  An input iterator.
+   *  @param  __last1   An input iterator.
+   *  @param  __first2  An input iterator.
+   *  @return   A boolean true or false.
+   *
+   *  This compares the elements of two ranges using @c == and returns true or
+   *  false depending on whether all of the corresponding elements of the
+   *  ranges are equal.
+  */
+  template<typename _II1, typename _II2>
+    _GLIBCXX20_CONSTEXPR
+    inline bool
+    equal(_II1 __first1, _II1 __last1, _II2 __first2)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_II1>)
+      __glibcxx_function_requires(_InputIteratorConcept<_II2>)
+      __glibcxx_function_requires(_EqualOpConcept<
+	    typename iterator_traits<_II1>::value_type,
+	    typename iterator_traits<_II2>::value_type>)
+      __glibcxx_requires_can_increment_range(__first1, __last1, __first2);
+
+      return std::__equal_aux(__first1, __last1, __first2);
+    }
+
+  /**
+   *  @brief Tests a range for element-wise equality.
+   *  @ingroup non_mutating_algorithms
+   *  @param  __first1  An input iterator.
+   *  @param  __last1   An input iterator.
+   *  @param  __first2  An input iterator.
+   *  @param __binary_pred A binary predicate @link functors
+   *                  functor@endlink.
+   *  @return         A boolean true or false.
+   *
+   *  This compares the elements of two ranges using the binary_pred
+   *  parameter, and returns true or
+   *  false depending on whether all of the corresponding elements of the
+   *  ranges are equal.
+  */
+  template<typename _IIter1, typename _IIter2, typename _BinaryPredicate>
+    _GLIBCXX20_CONSTEXPR
+    inline bool
+    equal(_IIter1 __first1, _IIter1 __last1,
+	  _IIter2 __first2, _BinaryPredicate __binary_pred)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_IIter1>)
+      __glibcxx_function_requires(_InputIteratorConcept<_IIter2>)
+      __glibcxx_requires_valid_range(__first1, __last1);
+
+      for (; __first1 != __last1; ++__first1, (void)++__first2)
+	if (!bool(__binary_pred(*__first1, *__first2)))
+	  return false;
+      return true;
+    }
+
+#if __cplusplus >= 201103L
+  // 4-iterator version of std::equal<It1, It2> for use in C++11.
+  template<typename _II1, typename _II2>
+    _GLIBCXX20_CONSTEXPR
+    inline bool
+    __equal4(_II1 __first1, _II1 __last1, _II2 __first2, _II2 __last2)
+    {
+      using _RATag = random_access_iterator_tag;
+      using _Cat1 = typename iterator_traits<_II1>::iterator_category;
+      using _Cat2 = typename iterator_traits<_II2>::iterator_category;
+      using _RAIters = __and_<is_same<_Cat1, _RATag>, is_same<_Cat2, _RATag>>;
+      if (_RAIters())
+	{
+	  auto __d1 = std::distance(__first1, __last1);
+	  auto __d2 = std::distance(__first2, __last2);
+	  if (__d1 != __d2)
+	    return false;
+	  return _GLIBCXX_STD_A::equal(__first1, __last1, __first2);
+	}
+
+      for (; __first1 != __last1 && __first2 != __last2;
+	  ++__first1, (void)++__first2)
+	if (!(*__first1 == *__first2))
+	  return false;
+      return __first1 == __last1 && __first2 == __last2;
+    }
+
+  // 4-iterator version of std::equal<It1, It2, BinaryPred> for use in C++11.
+  template<typename _II1, typename _II2, typename _BinaryPredicate>
+    _GLIBCXX20_CONSTEXPR
+    inline bool
+    __equal4(_II1 __first1, _II1 __last1, _II2 __first2, _II2 __last2,
+	     _BinaryPredicate __binary_pred)
+    {
+      using _RATag = random_access_iterator_tag;
+      using _Cat1 = typename iterator_traits<_II1>::iterator_category;
+      using _Cat2 = typename iterator_traits<_II2>::iterator_category;
+      using _RAIters = __and_<is_same<_Cat1, _RATag>, is_same<_Cat2, _RATag>>;
+      if (_RAIters())
+	{
+	  auto __d1 = std::distance(__first1, __last1);
+	  auto __d2 = std::distance(__first2, __last2);
+	  if (__d1 != __d2)
+	    return false;
+	  return _GLIBCXX_STD_A::equal(__first1, __last1, __first2,
+				       __binary_pred);
+	}
+
+      for (; __first1 != __last1 && __first2 != __last2;
+	  ++__first1, (void)++__first2)
+	if (!bool(__binary_pred(*__first1, *__first2)))
+	  return false;
+      return __first1 == __last1 && __first2 == __last2;
+    }
+#endif // C++11
+
+#if __cplusplus > 201103L
+
+#define __cpp_lib_robust_nonmodifying_seq_ops 201304L
+
+  /**
+   *  @brief Tests a range for element-wise equality.
+   *  @ingroup non_mutating_algorithms
+   *  @param  __first1  An input iterator.
+   *  @param  __last1   An input iterator.
+   *  @param  __first2  An input iterator.
+   *  @param  __last2   An input iterator.
+   *  @return   A boolean true or false.
+   *
+   *  This compares the elements of two ranges using @c == and returns true or
+   *  false depending on whether all of the corresponding elements of the
+   *  ranges are equal.
+  */
+  template<typename _II1, typename _II2>
+    _GLIBCXX20_CONSTEXPR
+    inline bool
+    equal(_II1 __first1, _II1 __last1, _II2 __first2, _II2 __last2)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_II1>)
+      __glibcxx_function_requires(_InputIteratorConcept<_II2>)
+      __glibcxx_function_requires(_EqualOpConcept<
+	    typename iterator_traits<_II1>::value_type,
+	    typename iterator_traits<_II2>::value_type>)
+      __glibcxx_requires_valid_range(__first1, __last1);
+      __glibcxx_requires_valid_range(__first2, __last2);
+
+      return _GLIBCXX_STD_A::__equal4(__first1, __last1, __first2, __last2);
+    }
+
+  /**
+   *  @brief Tests a range for element-wise equality.
+   *  @ingroup non_mutating_algorithms
+   *  @param  __first1  An input iterator.
+   *  @param  __last1   An input iterator.
+   *  @param  __first2  An input iterator.
+   *  @param  __last2   An input iterator.
+   *  @param __binary_pred A binary predicate @link functors
+   *                  functor@endlink.
+   *  @return         A boolean true or false.
+   *
+   *  This compares the elements of two ranges using the binary_pred
+   *  parameter, and returns true or
+   *  false depending on whether all of the corresponding elements of the
+   *  ranges are equal.
+  */
+  template<typename _IIter1, typename _IIter2, typename _BinaryPredicate>
+    _GLIBCXX20_CONSTEXPR
+    inline bool
+    equal(_IIter1 __first1, _IIter1 __last1,
+	  _IIter2 __first2, _IIter2 __last2, _BinaryPredicate __binary_pred)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_IIter1>)
+      __glibcxx_function_requires(_InputIteratorConcept<_IIter2>)
+      __glibcxx_requires_valid_range(__first1, __last1);
+      __glibcxx_requires_valid_range(__first2, __last2);
+
+      return _GLIBCXX_STD_A::__equal4(__first1, __last1, __first2, __last2,
+				      __binary_pred);
+    }
+#endif // C++14
+
+  /**
+   *  @brief Performs @b dictionary comparison on ranges.
+   *  @ingroup sorting_algorithms
+   *  @param  __first1  An input iterator.
+   *  @param  __last1   An input iterator.
+   *  @param  __first2  An input iterator.
+   *  @param  __last2   An input iterator.
+   *  @return   A boolean true or false.
+   *
+   *  <em>Returns true if the sequence of elements defined by the range
+   *  [first1,last1) is lexicographically less than the sequence of elements
+   *  defined by the range [first2,last2).  Returns false otherwise.</em>
+   *  (Quoted from [25.3.8]/1.)  If the iterators are all character pointers,
+   *  then this is an inline call to @c memcmp.
+  */
+  template<typename _II1, typename _II2>
+    _GLIBCXX20_CONSTEXPR
+    inline bool
+    lexicographical_compare(_II1 __first1, _II1 __last1,
+			    _II2 __first2, _II2 __last2)
+    {
+#ifdef _GLIBCXX_CONCEPT_CHECKS
+      // concept requirements
+      typedef typename iterator_traits<_II1>::value_type _ValueType1;
+      typedef typename iterator_traits<_II2>::value_type _ValueType2;
+#endif
+      __glibcxx_function_requires(_InputIteratorConcept<_II1>)
+      __glibcxx_function_requires(_InputIteratorConcept<_II2>)
+      __glibcxx_function_requires(_LessThanOpConcept<_ValueType1, _ValueType2>)
+      __glibcxx_function_requires(_LessThanOpConcept<_ValueType2, _ValueType1>)
+      __glibcxx_requires_valid_range(__first1, __last1);
+      __glibcxx_requires_valid_range(__first2, __last2);
+
+      return std::__lexicographical_compare_aux(__first1, __last1,
+						__first2, __last2);
+    }
+
+  /**
+   *  @brief Performs @b dictionary comparison on ranges.
+   *  @ingroup sorting_algorithms
+   *  @param  __first1  An input iterator.
+   *  @param  __last1   An input iterator.
+   *  @param  __first2  An input iterator.
+   *  @param  __last2   An input iterator.
+   *  @param  __comp  A @link comparison_functors comparison functor@endlink.
+   *  @return   A boolean true or false.
+   *
+   *  The same as the four-parameter @c lexicographical_compare, but uses the
+   *  comp parameter instead of @c <.
+  */
+  template<typename _II1, typename _II2, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    inline bool
+    lexicographical_compare(_II1 __first1, _II1 __last1,
+			    _II2 __first2, _II2 __last2, _Compare __comp)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_II1>)
+      __glibcxx_function_requires(_InputIteratorConcept<_II2>)
+      __glibcxx_requires_valid_range(__first1, __last1);
+      __glibcxx_requires_valid_range(__first2, __last2);
+
+      return std::__lexicographical_compare_impl
+	(__first1, __last1, __first2, __last2,
+	 __gnu_cxx::__ops::__iter_comp_iter(__comp));
+    }
+
+#if __cpp_lib_three_way_comparison
+  // Iter points to a contiguous range of unsigned narrow character type
+  // or std::byte, suitable for comparison by memcmp.
+  template<typename _Iter>
+    concept __is_byte_iter = contiguous_iterator<_Iter>
+      && __is_memcmp_ordered<iter_value_t<_Iter>>::__value;
+
+  // Return a struct with two members, initialized to the smaller of x and y
+  // (or x if they compare equal) and the result of the comparison x <=> y.
+  template<typename _Tp>
+    constexpr auto
+    __min_cmp(_Tp __x, _Tp __y)
+    {
+      struct _Res {
+	_Tp _M_min;
+	decltype(__x <=> __y) _M_cmp;
+      };
+      auto __c = __x <=> __y;
+      if (__c > 0)
+	return _Res{__y, __c};
+      return _Res{__x, __c};
+    }
+
+  /**
+   *  @brief Performs dictionary comparison on ranges.
+   *  @ingroup sorting_algorithms
+   *  @param  __first1  An input iterator.
+   *  @param  __last1   An input iterator.
+   *  @param  __first2  An input iterator.
+   *  @param  __last2   An input iterator.
+   *  @param  __comp  A @link comparison_functors comparison functor@endlink.
+   *  @return   The comparison category that `__comp(*__first1, *__first2)`
+   *		returns.
+  */
+  template<typename _InputIter1, typename _InputIter2, typename _Comp>
+    constexpr auto
+    lexicographical_compare_three_way(_InputIter1 __first1,
+				      _InputIter1 __last1,
+				      _InputIter2 __first2,
+				      _InputIter2 __last2,
+				      _Comp __comp)
+    -> decltype(__comp(*__first1, *__first2))
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIter1>)
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIter2>)
+      __glibcxx_requires_valid_range(__first1, __last1);
+      __glibcxx_requires_valid_range(__first2, __last2);
+
+      using _Cat = decltype(__comp(*__first1, *__first2));
+      static_assert(same_as<common_comparison_category_t<_Cat>, _Cat>);
+
+      if (!std::__is_constant_evaluated())
+	if constexpr (same_as<_Comp, __detail::_Synth3way>
+		      || same_as<_Comp, compare_three_way>)
+	  if constexpr (__is_byte_iter<_InputIter1>)
+	    if constexpr (__is_byte_iter<_InputIter2>)
+	      {
+		const auto [__len, __lencmp] = _GLIBCXX_STD_A::
+		  __min_cmp(__last1 - __first1, __last2 - __first2);
+		if (__len)
+		  {
+		    const auto __c
+		      = __builtin_memcmp(&*__first1, &*__first2, __len) <=> 0;
+		    if (__c != 0)
+		      return __c;
+		  }
+		return __lencmp;
+	      }
+
+      while (__first1 != __last1)
+	{
+	  if (__first2 == __last2)
+	    return strong_ordering::greater;
+	  if (auto __cmp = __comp(*__first1, *__first2); __cmp != 0)
+	    return __cmp;
+	  ++__first1;
+	  ++__first2;
+	}
+      return (__first2 == __last2) <=> true; // See PR 94006
+    }
+
+  template<typename _InputIter1, typename _InputIter2>
+    constexpr auto
+    lexicographical_compare_three_way(_InputIter1 __first1,
+				      _InputIter1 __last1,
+				      _InputIter2 __first2,
+				      _InputIter2 __last2)
+    {
+      return _GLIBCXX_STD_A::
+	lexicographical_compare_three_way(__first1, __last1, __first2, __last2,
+					  compare_three_way{});
+    }
+#endif // three_way_comparison
+
+  template<typename _InputIterator1, typename _InputIterator2,
+	   typename _BinaryPredicate>
+    _GLIBCXX20_CONSTEXPR
+    pair<_InputIterator1, _InputIterator2>
+    __mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
+	       _InputIterator2 __first2, _BinaryPredicate __binary_pred)
+    {
+      while (__first1 != __last1 && __binary_pred(__first1, __first2))
+	{
+	  ++__first1;
+	  ++__first2;
+	}
+      return pair<_InputIterator1, _InputIterator2>(__first1, __first2);
+    }
+
+  /**
+   *  @brief Finds the places in ranges which don't match.
+   *  @ingroup non_mutating_algorithms
+   *  @param  __first1  An input iterator.
+   *  @param  __last1   An input iterator.
+   *  @param  __first2  An input iterator.
+   *  @return   A pair of iterators pointing to the first mismatch.
+   *
+   *  This compares the elements of two ranges using @c == and returns a pair
+   *  of iterators.  The first iterator points into the first range, the
+   *  second iterator points into the second range, and the elements pointed
+   *  to by the iterators are not equal.
+  */
+  template<typename _InputIterator1, typename _InputIterator2>
+    _GLIBCXX20_CONSTEXPR
+    inline pair<_InputIterator1, _InputIterator2>
+    mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
+	     _InputIterator2 __first2)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
+      __glibcxx_function_requires(_EqualOpConcept<
+	    typename iterator_traits<_InputIterator1>::value_type,
+	    typename iterator_traits<_InputIterator2>::value_type>)
+      __glibcxx_requires_valid_range(__first1, __last1);
+
+      return _GLIBCXX_STD_A::__mismatch(__first1, __last1, __first2,
+			     __gnu_cxx::__ops::__iter_equal_to_iter());
+    }
+
+  /**
+   *  @brief Finds the places in ranges which don't match.
+   *  @ingroup non_mutating_algorithms
+   *  @param  __first1  An input iterator.
+   *  @param  __last1   An input iterator.
+   *  @param  __first2  An input iterator.
+   *  @param __binary_pred A binary predicate @link functors
+   *         functor@endlink.
+   *  @return   A pair of iterators pointing to the first mismatch.
+   *
+   *  This compares the elements of two ranges using the binary_pred
+   *  parameter, and returns a pair
+   *  of iterators.  The first iterator points into the first range, the
+   *  second iterator points into the second range, and the elements pointed
+   *  to by the iterators are not equal.
+  */
+  template<typename _InputIterator1, typename _InputIterator2,
+	   typename _BinaryPredicate>
+    _GLIBCXX20_CONSTEXPR
+    inline pair<_InputIterator1, _InputIterator2>
+    mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
+	     _InputIterator2 __first2, _BinaryPredicate __binary_pred)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
+      __glibcxx_requires_valid_range(__first1, __last1);
+
+      return _GLIBCXX_STD_A::__mismatch(__first1, __last1, __first2,
+	__gnu_cxx::__ops::__iter_comp_iter(__binary_pred));
+    }
+
+#if __cplusplus > 201103L
+
+  template<typename _InputIterator1, typename _InputIterator2,
+	   typename _BinaryPredicate>
+    _GLIBCXX20_CONSTEXPR
+    pair<_InputIterator1, _InputIterator2>
+    __mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
+	       _InputIterator2 __first2, _InputIterator2 __last2,
+	       _BinaryPredicate __binary_pred)
+    {
+      while (__first1 != __last1 && __first2 != __last2
+	     && __binary_pred(__first1, __first2))
+	{
+	  ++__first1;
+	  ++__first2;
+	}
+      return pair<_InputIterator1, _InputIterator2>(__first1, __first2);
+    }
+
+  /**
+   *  @brief Finds the places in ranges which don't match.
+   *  @ingroup non_mutating_algorithms
+   *  @param  __first1  An input iterator.
+   *  @param  __last1   An input iterator.
+   *  @param  __first2  An input iterator.
+   *  @param  __last2   An input iterator.
+   *  @return   A pair of iterators pointing to the first mismatch.
+   *
+   *  This compares the elements of two ranges using @c == and returns a pair
+   *  of iterators.  The first iterator points into the first range, the
+   *  second iterator points into the second range, and the elements pointed
+   *  to by the iterators are not equal.
+  */
+  template<typename _InputIterator1, typename _InputIterator2>
+    _GLIBCXX20_CONSTEXPR
+    inline pair<_InputIterator1, _InputIterator2>
+    mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
+	     _InputIterator2 __first2, _InputIterator2 __last2)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
+      __glibcxx_function_requires(_EqualOpConcept<
+	    typename iterator_traits<_InputIterator1>::value_type,
+	    typename iterator_traits<_InputIterator2>::value_type>)
+      __glibcxx_requires_valid_range(__first1, __last1);
+      __glibcxx_requires_valid_range(__first2, __last2);
+
+      return _GLIBCXX_STD_A::__mismatch(__first1, __last1, __first2, __last2,
+			     __gnu_cxx::__ops::__iter_equal_to_iter());
+    }
+
+  /**
+   *  @brief Finds the places in ranges which don't match.
+   *  @ingroup non_mutating_algorithms
+   *  @param  __first1  An input iterator.
+   *  @param  __last1   An input iterator.
+   *  @param  __first2  An input iterator.
+   *  @param  __last2   An input iterator.
+   *  @param __binary_pred A binary predicate @link functors
+   *         functor@endlink.
+   *  @return   A pair of iterators pointing to the first mismatch.
+   *
+   *  This compares the elements of two ranges using the binary_pred
+   *  parameter, and returns a pair
+   *  of iterators.  The first iterator points into the first range, the
+   *  second iterator points into the second range, and the elements pointed
+   *  to by the iterators are not equal.
+  */
+  template<typename _InputIterator1, typename _InputIterator2,
+	   typename _BinaryPredicate>
+    _GLIBCXX20_CONSTEXPR
+    inline pair<_InputIterator1, _InputIterator2>
+    mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
+	     _InputIterator2 __first2, _InputIterator2 __last2,
+	     _BinaryPredicate __binary_pred)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
+      __glibcxx_requires_valid_range(__first1, __last1);
+      __glibcxx_requires_valid_range(__first2, __last2);
+
+      return _GLIBCXX_STD_A::__mismatch(__first1, __last1, __first2, __last2,
+			     __gnu_cxx::__ops::__iter_comp_iter(__binary_pred));
+    }
+#endif
+
+_GLIBCXX_END_NAMESPACE_ALGO
+
+  /// This is an overload used by find algos for the Input Iterator case.
+  template<typename _InputIterator, typename _Predicate>
+    _GLIBCXX20_CONSTEXPR
+    inline _InputIterator
+    __find_if(_InputIterator __first, _InputIterator __last,
+	      _Predicate __pred, input_iterator_tag)
+    {
+      while (__first != __last && !__pred(__first))
+	++__first;
+      return __first;
+    }
+
+  /// This is an overload used by find algos for the RAI case.
+  template<typename _RandomAccessIterator, typename _Predicate>
+    _GLIBCXX20_CONSTEXPR
+    _RandomAccessIterator
+    __find_if(_RandomAccessIterator __first, _RandomAccessIterator __last,
+	      _Predicate __pred, random_access_iterator_tag)
+    {
+      typename iterator_traits<_RandomAccessIterator>::difference_type
+	__trip_count = (__last - __first) >> 2;
+
+      for (; __trip_count > 0; --__trip_count)
+	{
+	  if (__pred(__first))
+	    return __first;
+	  ++__first;
+
+	  if (__pred(__first))
+	    return __first;
+	  ++__first;
+
+	  if (__pred(__first))
+	    return __first;
+	  ++__first;
+
+	  if (__pred(__first))
+	    return __first;
+	  ++__first;
+	}
+
+      switch (__last - __first)
+	{
+	case 3:
+	  if (__pred(__first))
+	    return __first;
+	  ++__first;
+	  // FALLTHRU
+	case 2:
+	  if (__pred(__first))
+	    return __first;
+	  ++__first;
+	  // FALLTHRU
+	case 1:
+	  if (__pred(__first))
+	    return __first;
+	  ++__first;
+	  // FALLTHRU
+	case 0:
+	default:
+	  return __last;
+	}
+    }
+
+  template<typename _Iterator, typename _Predicate>
+    _GLIBCXX20_CONSTEXPR
+    inline _Iterator
+    __find_if(_Iterator __first, _Iterator __last, _Predicate __pred)
+    {
+      return __find_if(__first, __last, __pred,
+		       std::__iterator_category(__first));
+    }
+
+  template<typename _InputIterator, typename _Predicate>
+    _GLIBCXX20_CONSTEXPR
+    typename iterator_traits<_InputIterator>::difference_type
+    __count_if(_InputIterator __first, _InputIterator __last, _Predicate __pred)
+    {
+      typename iterator_traits<_InputIterator>::difference_type __n = 0;
+      for (; __first != __last; ++__first)
+	if (__pred(__first))
+	  ++__n;
+      return __n;
+    }
+
+  template<typename _ForwardIterator, typename _Predicate>
+    _GLIBCXX20_CONSTEXPR
+    _ForwardIterator
+    __remove_if(_ForwardIterator __first, _ForwardIterator __last,
+		_Predicate __pred)
+    {
+      __first = std::__find_if(__first, __last, __pred);
+      if (__first == __last)
+	return __first;
+      _ForwardIterator __result = __first;
+      ++__first;
+      for (; __first != __last; ++__first)
+	if (!__pred(__first))
+	  {
+	    *__result = _GLIBCXX_MOVE(*__first);
+	    ++__result;
+	  }
+      return __result;
+    }
+
+#if __cplusplus >= 201103L
+  template<typename _ForwardIterator1, typename _ForwardIterator2,
+	   typename _BinaryPredicate>
+    _GLIBCXX20_CONSTEXPR
+    bool
+    __is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
+		     _ForwardIterator2 __first2, _BinaryPredicate __pred)
+    {
+      // Efficiently compare identical prefixes:  O(N) if sequences
+      // have the same elements in the same order.
+      for (; __first1 != __last1; ++__first1, (void)++__first2)
+	if (!__pred(__first1, __first2))
+	  break;
+
+      if (__first1 == __last1)
+	return true;
+
+      // Establish __last2 assuming equal ranges by iterating over the
+      // rest of the list.
+      _ForwardIterator2 __last2 = __first2;
+      std::advance(__last2, std::distance(__first1, __last1));
+      for (_ForwardIterator1 __scan = __first1; __scan != __last1; ++__scan)
+	{
+	  if (__scan != std::__find_if(__first1, __scan,
+			  __gnu_cxx::__ops::__iter_comp_iter(__pred, __scan)))
+	    continue; // We've seen this one before.
+
+	  auto __matches
+	    = std::__count_if(__first2, __last2,
+			__gnu_cxx::__ops::__iter_comp_iter(__pred, __scan));
+	  if (0 == __matches ||
+	      std::__count_if(__scan, __last1,
+			__gnu_cxx::__ops::__iter_comp_iter(__pred, __scan))
+	      != __matches)
+	    return false;
+	}
+      return true;
+    }
+
+  /**
+   *  @brief  Checks whether a permutation of the second sequence is equal
+   *          to the first sequence.
+   *  @ingroup non_mutating_algorithms
+   *  @param  __first1  Start of first range.
+   *  @param  __last1   End of first range.
+   *  @param  __first2  Start of second range.
+   *  @return true if there exists a permutation of the elements in the range
+   *          [__first2, __first2 + (__last1 - __first1)), beginning with
+   *          ForwardIterator2 begin, such that equal(__first1, __last1, begin)
+   *          returns true; otherwise, returns false.
+  */
+  template<typename _ForwardIterator1, typename _ForwardIterator2>
+    _GLIBCXX20_CONSTEXPR
+    inline bool
+    is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
+		   _ForwardIterator2 __first2)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator1>)
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator2>)
+      __glibcxx_function_requires(_EqualOpConcept<
+		typename iterator_traits<_ForwardIterator1>::value_type,
+		typename iterator_traits<_ForwardIterator2>::value_type>)
+      __glibcxx_requires_valid_range(__first1, __last1);
+
+      return std::__is_permutation(__first1, __last1, __first2,
+				   __gnu_cxx::__ops::__iter_equal_to_iter());
+    }
+#endif // C++11
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+// NB: This file is included within many other C++ includes, as a way
+// of getting the base algorithms. So, make sure that parallel bits
+// come in too if requested.
+#ifdef _GLIBCXX_PARALLEL
+# include <parallel/algobase.h>
+#endif
+
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stl_algobase.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stl_algobase.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stl_bvector.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stl_bvector.h
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stl_bvector.h
@@ -0,0 +1,1585 @@
+// vector<bool> specialization -*- C++ -*-
+
+// Copyright (C) 2001-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/*
+ *
+ * Copyright (c) 1994
+ * Hewlett-Packard Company
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Hewlett-Packard Company makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ *
+ *
+ * Copyright (c) 1996-1999
+ * Silicon Graphics Computer Systems, Inc.
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Silicon Graphics makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ */
+
+/** @file bits/stl_bvector.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{vector}
+ */
+
+#ifndef _STL_BVECTOR_H
+#define _STL_BVECTOR_H 1
+
+#if __cplusplus >= 201103L
+#include <initializer_list>
+#include <bits/functional_hash.h>
+#endif
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  typedef unsigned long _Bit_type;
+  enum { _S_word_bit = int(__CHAR_BIT__ * sizeof(_Bit_type)) };
+
+  __attribute__((__nonnull__))
+  _GLIBCXX20_CONSTEXPR
+  void
+  __fill_bvector_n(_Bit_type*, size_t, bool) _GLIBCXX_NOEXCEPT;
+
+_GLIBCXX_BEGIN_NAMESPACE_CONTAINER
+
+  struct _Bit_reference
+  {
+    _Bit_type * _M_p;
+    _Bit_type _M_mask;
+
+    _GLIBCXX20_CONSTEXPR
+    _Bit_reference(_Bit_type * __x, _Bit_type __y)
+    : _M_p(__x), _M_mask(__y) { }
+
+    _GLIBCXX20_CONSTEXPR
+    _Bit_reference() _GLIBCXX_NOEXCEPT : _M_p(0), _M_mask(0) { }
+
+#if __cplusplus >= 201103L
+    _Bit_reference(const _Bit_reference&) = default;
+#endif
+
+    _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
+    operator bool() const _GLIBCXX_NOEXCEPT
+    { return !!(*_M_p & _M_mask); }
+
+    _GLIBCXX20_CONSTEXPR
+    _Bit_reference&
+    operator=(bool __x) _GLIBCXX_NOEXCEPT
+    {
+      if (__x)
+	*_M_p |= _M_mask;
+      else
+	*_M_p &= ~_M_mask;
+      return *this;
+    }
+
+    _GLIBCXX20_CONSTEXPR
+    _Bit_reference&
+    operator=(const _Bit_reference& __x) _GLIBCXX_NOEXCEPT
+    { return *this = bool(__x); }
+
+    _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
+    bool
+    operator==(const _Bit_reference& __x) const
+    { return bool(*this) == bool(__x); }
+
+    _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
+    bool
+    operator<(const _Bit_reference& __x) const
+    { return !bool(*this) && bool(__x); }
+
+    _GLIBCXX20_CONSTEXPR
+    void
+    flip() _GLIBCXX_NOEXCEPT
+    { *_M_p ^= _M_mask; }
+
+#if __cplusplus >= 201103L
+    _GLIBCXX20_CONSTEXPR
+    friend void
+    swap(_Bit_reference __x, _Bit_reference __y) noexcept
+    {
+      bool __tmp = __x;
+      __x = __y;
+      __y = __tmp;
+    }
+
+    _GLIBCXX20_CONSTEXPR
+    friend void
+    swap(_Bit_reference __x, bool& __y) noexcept
+    {
+      bool __tmp = __x;
+      __x = __y;
+      __y = __tmp;
+    }
+
+    _GLIBCXX20_CONSTEXPR
+    friend void
+    swap(bool& __x, _Bit_reference __y) noexcept
+    {
+      bool __tmp = __x;
+      __x = __y;
+      __y = __tmp;
+    }
+#endif
+  };
+
+// Ignore warnings about std::iterator.
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+  struct _Bit_iterator_base
+  : public std::iterator<std::random_access_iterator_tag, bool>
+  {
+    _Bit_type * _M_p;
+    unsigned int _M_offset;
+
+    _GLIBCXX20_CONSTEXPR
+    _Bit_iterator_base(_Bit_type * __x, unsigned int __y)
+    : _M_p(__x), _M_offset(__y) { }
+
+    _GLIBCXX20_CONSTEXPR
+    void
+    _M_bump_up()
+    {
+      if (_M_offset++ == int(_S_word_bit) - 1)
+	{
+	  _M_offset = 0;
+	  ++_M_p;
+	}
+    }
+
+    _GLIBCXX20_CONSTEXPR
+    void
+    _M_bump_down()
+    {
+      if (_M_offset-- == 0)
+	{
+	  _M_offset = int(_S_word_bit) - 1;
+	  --_M_p;
+	}
+    }
+
+    _GLIBCXX20_CONSTEXPR
+    void
+    _M_incr(ptrdiff_t __i)
+    {
+      difference_type __n = __i + _M_offset;
+      _M_p += __n / int(_S_word_bit);
+      __n = __n % int(_S_word_bit);
+      if (__n < 0)
+	{
+	  __n += int(_S_word_bit);
+	  --_M_p;
+	}
+      _M_offset = static_cast<unsigned int>(__n);
+    }
+
+    _GLIBCXX_NODISCARD
+    friend _GLIBCXX20_CONSTEXPR bool
+    operator==(const _Bit_iterator_base& __x, const _Bit_iterator_base& __y)
+    { return __x._M_p == __y._M_p && __x._M_offset == __y._M_offset; }
+
+#if __cpp_lib_three_way_comparison
+    [[nodiscard]]
+    friend constexpr strong_ordering
+    operator<=>(const _Bit_iterator_base& __x, const _Bit_iterator_base& __y)
+    noexcept
+    {
+      if (const auto __cmp = __x._M_p <=> __y._M_p; __cmp != 0)
+	return __cmp;
+      return __x._M_offset <=> __y._M_offset;
+    }
+#else
+    _GLIBCXX_NODISCARD
+    friend bool
+    operator<(const _Bit_iterator_base& __x, const _Bit_iterator_base& __y)
+    {
+      return __x._M_p < __y._M_p
+	    || (__x._M_p == __y._M_p && __x._M_offset < __y._M_offset);
+    }
+
+    _GLIBCXX_NODISCARD
+    friend bool
+    operator!=(const _Bit_iterator_base& __x, const _Bit_iterator_base& __y)
+    { return !(__x == __y); }
+
+    _GLIBCXX_NODISCARD
+    friend bool
+    operator>(const _Bit_iterator_base& __x, const _Bit_iterator_base& __y)
+    { return __y < __x; }
+
+    _GLIBCXX_NODISCARD
+    friend bool
+    operator<=(const _Bit_iterator_base& __x, const _Bit_iterator_base& __y)
+    { return !(__y < __x); }
+
+    _GLIBCXX_NODISCARD
+    friend bool
+    operator>=(const _Bit_iterator_base& __x, const _Bit_iterator_base& __y)
+    { return !(__x < __y); }
+#endif // three-way comparison
+
+    friend _GLIBCXX20_CONSTEXPR ptrdiff_t
+    operator-(const _Bit_iterator_base& __x, const _Bit_iterator_base& __y)
+    {
+      return (int(_S_word_bit) * (__x._M_p - __y._M_p)
+	      + __x._M_offset - __y._M_offset);
+    }
+  };
+#pragma GCC diagnostic pop
+
+  struct _Bit_iterator : public _Bit_iterator_base
+  {
+    typedef _Bit_reference  reference;
+#if __cplusplus > 201703L
+    typedef void	    pointer;
+#else
+    typedef _Bit_reference* pointer;
+#endif
+    typedef _Bit_iterator   iterator;
+
+    _GLIBCXX20_CONSTEXPR
+    _Bit_iterator() : _Bit_iterator_base(0, 0) { }
+
+    _GLIBCXX20_CONSTEXPR
+    _Bit_iterator(_Bit_type * __x, unsigned int __y)
+    : _Bit_iterator_base(__x, __y) { }
+
+    _GLIBCXX20_CONSTEXPR
+    iterator
+    _M_const_cast() const
+    { return *this; }
+
+    _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
+    reference
+    operator*() const
+    { return reference(_M_p, 1UL << _M_offset); }
+
+    _GLIBCXX20_CONSTEXPR
+    iterator&
+    operator++()
+    {
+      _M_bump_up();
+      return *this;
+    }
+
+    _GLIBCXX20_CONSTEXPR
+    iterator
+    operator++(int)
+    {
+      iterator __tmp = *this;
+      _M_bump_up();
+      return __tmp;
+    }
+
+    _GLIBCXX20_CONSTEXPR
+    iterator&
+    operator--()
+    {
+      _M_bump_down();
+      return *this;
+    }
+
+    _GLIBCXX20_CONSTEXPR
+    iterator
+    operator--(int)
+    {
+      iterator __tmp = *this;
+      _M_bump_down();
+      return __tmp;
+    }
+
+    _GLIBCXX20_CONSTEXPR
+    iterator&
+    operator+=(difference_type __i)
+    {
+      _M_incr(__i);
+      return *this;
+    }
+
+    _GLIBCXX20_CONSTEXPR
+    iterator&
+    operator-=(difference_type __i)
+    {
+      *this += -__i;
+      return *this;
+    }
+
+    _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
+    reference
+    operator[](difference_type __i) const
+    { return *(*this + __i); }
+
+    _GLIBCXX_NODISCARD
+    friend _GLIBCXX20_CONSTEXPR iterator
+    operator+(const iterator& __x, difference_type __n)
+    {
+      iterator __tmp = __x;
+      __tmp += __n;
+      return __tmp;
+    }
+
+    _GLIBCXX_NODISCARD
+    friend _GLIBCXX20_CONSTEXPR iterator
+    operator+(difference_type __n, const iterator& __x)
+    { return __x + __n; }
+
+    _GLIBCXX_NODISCARD
+    friend _GLIBCXX20_CONSTEXPR iterator
+    operator-(const iterator& __x, difference_type __n)
+    {
+      iterator __tmp = __x;
+      __tmp -= __n;
+      return __tmp;
+    }
+  };
+
+  struct _Bit_const_iterator : public _Bit_iterator_base
+  {
+    typedef bool                 reference;
+    typedef bool                 const_reference;
+#if __cplusplus > 201703L
+    typedef void	    pointer;
+#else
+    typedef const bool*          pointer;
+#endif
+    typedef _Bit_const_iterator  const_iterator;
+
+    _GLIBCXX20_CONSTEXPR
+    _Bit_const_iterator() : _Bit_iterator_base(0, 0) { }
+
+    _GLIBCXX20_CONSTEXPR
+    _Bit_const_iterator(_Bit_type * __x, unsigned int __y)
+    : _Bit_iterator_base(__x, __y) { }
+
+    _GLIBCXX20_CONSTEXPR
+    _Bit_const_iterator(const _Bit_iterator& __x)
+    : _Bit_iterator_base(__x._M_p, __x._M_offset) { }
+
+    _GLIBCXX20_CONSTEXPR
+    _Bit_iterator
+    _M_const_cast() const
+    { return _Bit_iterator(_M_p, _M_offset); }
+
+    _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
+    const_reference
+    operator*() const
+    { return _Bit_reference(_M_p, 1UL << _M_offset); }
+
+    _GLIBCXX20_CONSTEXPR
+    const_iterator&
+    operator++()
+    {
+      _M_bump_up();
+      return *this;
+    }
+
+    _GLIBCXX20_CONSTEXPR
+    const_iterator
+    operator++(int)
+    {
+      const_iterator __tmp = *this;
+      _M_bump_up();
+      return __tmp;
+    }
+
+    _GLIBCXX20_CONSTEXPR
+    const_iterator&
+    operator--()
+    {
+      _M_bump_down();
+      return *this;
+    }
+
+    _GLIBCXX20_CONSTEXPR
+    const_iterator
+    operator--(int)
+    {
+      const_iterator __tmp = *this;
+      _M_bump_down();
+      return __tmp;
+    }
+
+    _GLIBCXX20_CONSTEXPR
+    const_iterator&
+    operator+=(difference_type __i)
+    {
+      _M_incr(__i);
+      return *this;
+    }
+
+    _GLIBCXX20_CONSTEXPR
+    const_iterator&
+    operator-=(difference_type __i)
+    {
+      *this += -__i;
+      return *this;
+    }
+
+    _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
+    const_reference
+    operator[](difference_type __i) const
+    { return *(*this + __i); }
+
+    _GLIBCXX_NODISCARD
+    friend _GLIBCXX20_CONSTEXPR const_iterator
+    operator+(const const_iterator& __x, difference_type __n)
+    {
+      const_iterator __tmp = __x;
+      __tmp += __n;
+      return __tmp;
+    }
+
+    _GLIBCXX_NODISCARD
+    friend _GLIBCXX20_CONSTEXPR const_iterator
+    operator-(const const_iterator& __x, difference_type __n)
+    {
+      const_iterator __tmp = __x;
+      __tmp -= __n;
+      return __tmp;
+    }
+
+    _GLIBCXX_NODISCARD
+    friend _GLIBCXX20_CONSTEXPR const_iterator
+    operator+(difference_type __n, const const_iterator& __x)
+    { return __x + __n; }
+  };
+
+  template<typename _Alloc>
+    struct _Bvector_base
+    {
+      typedef typename __gnu_cxx::__alloc_traits<_Alloc>::template
+        rebind<_Bit_type>::other _Bit_alloc_type;
+      typedef typename __gnu_cxx::__alloc_traits<_Bit_alloc_type>
+	_Bit_alloc_traits;
+      typedef typename _Bit_alloc_traits::pointer _Bit_pointer;
+
+      struct _Bvector_impl_data
+      {
+#if !_GLIBCXX_INLINE_VERSION
+	_Bit_iterator	_M_start;
+#else
+	// We don't need the offset field for the start, it's always zero.
+	struct {
+	  _Bit_type* _M_p;
+	  // Allow assignment from iterators (assume offset is zero):
+	  _GLIBCXX20_CONSTEXPR
+	  void operator=(_Bit_iterator __it) { _M_p = __it._M_p; }
+	} _M_start;
+#endif
+	_Bit_iterator	_M_finish;
+	_Bit_pointer	_M_end_of_storage;
+
+	_GLIBCXX20_CONSTEXPR
+	_Bvector_impl_data() _GLIBCXX_NOEXCEPT
+	: _M_start(), _M_finish(), _M_end_of_storage()
+	{ }
+
+#if __cplusplus >= 201103L
+	_Bvector_impl_data(const _Bvector_impl_data&) = default;
+
+	_Bvector_impl_data&
+	operator=(const _Bvector_impl_data&) = default;
+
+	_GLIBCXX20_CONSTEXPR
+	_Bvector_impl_data(_Bvector_impl_data&& __x) noexcept
+	: _Bvector_impl_data(__x)
+	{ __x._M_reset(); }
+
+	_GLIBCXX20_CONSTEXPR
+	void
+	_M_move_data(_Bvector_impl_data&& __x) noexcept
+	{
+	  *this = __x;
+	  __x._M_reset();
+	}
+#endif
+
+	_GLIBCXX20_CONSTEXPR
+	void
+	_M_reset() _GLIBCXX_NOEXCEPT
+	{ *this = _Bvector_impl_data(); }
+
+	_GLIBCXX20_CONSTEXPR
+	void
+	_M_swap_data(_Bvector_impl_data& __x) _GLIBCXX_NOEXCEPT
+	{
+	  // Do not use std::swap(_M_start, __x._M_start), etc as it loses
+	  // information used by TBAA.
+	  std::swap(*this, __x);
+	}
+      };
+
+      struct _Bvector_impl
+	: public _Bit_alloc_type, public _Bvector_impl_data
+      {
+	_GLIBCXX20_CONSTEXPR
+	_Bvector_impl() _GLIBCXX_NOEXCEPT_IF(
+	  is_nothrow_default_constructible<_Bit_alloc_type>::value)
+	: _Bit_alloc_type()
+	{ }
+
+	_GLIBCXX20_CONSTEXPR
+	_Bvector_impl(const _Bit_alloc_type& __a) _GLIBCXX_NOEXCEPT
+	: _Bit_alloc_type(__a)
+	{ }
+
+#if __cplusplus >= 201103L
+	// Not defaulted, to enforce noexcept(true) even when
+	// !is_nothrow_move_constructible<_Bit_alloc_type>.
+	_GLIBCXX20_CONSTEXPR
+	_Bvector_impl(_Bvector_impl&& __x) noexcept
+	: _Bit_alloc_type(std::move(__x)), _Bvector_impl_data(std::move(__x))
+	{ }
+
+	_GLIBCXX20_CONSTEXPR
+	_Bvector_impl(_Bit_alloc_type&& __a, _Bvector_impl&& __x) noexcept
+	: _Bit_alloc_type(std::move(__a)), _Bvector_impl_data(std::move(__x))
+	{ }
+#endif
+
+	_GLIBCXX20_CONSTEXPR
+	_Bit_type*
+	_M_end_addr() const _GLIBCXX_NOEXCEPT
+	{
+	  if (this->_M_end_of_storage)
+	    return std::__addressof(this->_M_end_of_storage[-1]) + 1;
+	  return 0;
+	}
+      };
+
+    public:
+      typedef _Alloc allocator_type;
+
+      _GLIBCXX20_CONSTEXPR
+      _Bit_alloc_type&
+      _M_get_Bit_allocator() _GLIBCXX_NOEXCEPT
+      { return this->_M_impl; }
+
+      _GLIBCXX20_CONSTEXPR
+      const _Bit_alloc_type&
+      _M_get_Bit_allocator() const _GLIBCXX_NOEXCEPT
+      { return this->_M_impl; }
+
+      _GLIBCXX20_CONSTEXPR
+      allocator_type
+      get_allocator() const _GLIBCXX_NOEXCEPT
+      { return allocator_type(_M_get_Bit_allocator()); }
+
+#if __cplusplus >= 201103L
+      _Bvector_base() = default;
+#else
+      _Bvector_base() { }
+#endif
+
+      _GLIBCXX20_CONSTEXPR
+      _Bvector_base(const allocator_type& __a)
+      : _M_impl(__a) { }
+
+#if __cplusplus >= 201103L
+      _Bvector_base(_Bvector_base&&) = default;
+
+      _GLIBCXX20_CONSTEXPR
+      _Bvector_base(_Bvector_base&& __x, const allocator_type& __a) noexcept
+      : _M_impl(_Bit_alloc_type(__a), std::move(__x._M_impl))
+      { }
+#endif
+
+      _GLIBCXX20_CONSTEXPR
+      ~_Bvector_base()
+      { this->_M_deallocate(); }
+
+    protected:
+      _Bvector_impl _M_impl;
+
+      _GLIBCXX20_CONSTEXPR
+      _Bit_pointer
+      _M_allocate(size_t __n)
+      {
+	_Bit_pointer __p = _Bit_alloc_traits::allocate(_M_impl, _S_nword(__n));
+#if __cpp_lib_is_constant_evaluated
+	if (std::is_constant_evaluated())
+	{
+	  __n = _S_nword(__n);
+	  for (size_t __i = 0; __i < __n; ++__i)
+	    __p[__i] = 0ul;
+	}
+#endif
+	return __p;
+      }
+
+      _GLIBCXX20_CONSTEXPR
+      void
+      _M_deallocate()
+      {
+	if (_M_impl._M_start._M_p)
+	  {
+	    const size_t __n = _M_impl._M_end_addr() - _M_impl._M_start._M_p;
+	    _Bit_alloc_traits::deallocate(_M_impl,
+					  _M_impl._M_end_of_storage - __n,
+					  __n);
+	    _M_impl._M_reset();
+	  }
+      }
+
+#if __cplusplus >= 201103L
+      _GLIBCXX20_CONSTEXPR
+      void
+      _M_move_data(_Bvector_base&& __x) noexcept
+      { _M_impl._M_move_data(std::move(__x._M_impl)); }
+#endif
+
+      _GLIBCXX_CONSTEXPR
+      static size_t
+      _S_nword(size_t __n)
+      { return (__n + int(_S_word_bit) - 1) / int(_S_word_bit); }
+    };
+
+  /**
+   *  @brief  A specialization of vector for booleans which offers fixed time
+   *  access to individual elements in any order.
+   *
+   *  @ingroup sequences
+   *
+   *  @tparam _Alloc  Allocator type.
+   *
+   *  Note that vector<bool> does not actually meet the requirements for being
+   *  a container.  This is because the reference and pointer types are not
+   *  really references and pointers to bool.  See DR96 for details.  @see
+   *  vector for function documentation.
+   *
+   *  In some terminology a %vector can be described as a dynamic
+   *  C-style array, it offers fast and efficient access to individual
+   *  elements in any order and saves the user from worrying about
+   *  memory and size allocation.  Subscripting ( @c [] ) access is
+   *  also provided as with C-style arrays.
+  */
+  template<typename _Alloc>
+    class vector<bool, _Alloc> : protected _Bvector_base<_Alloc>
+    {
+      typedef _Bvector_base<_Alloc>			_Base;
+      typedef typename _Base::_Bit_pointer		_Bit_pointer;
+      typedef typename _Base::_Bit_alloc_traits		_Bit_alloc_traits;
+
+#if __cplusplus >= 201103L
+      friend struct std::hash<vector>;
+#endif
+
+    public:
+      typedef bool					value_type;
+      typedef size_t					size_type;
+      typedef ptrdiff_t					difference_type;
+      typedef _Bit_reference				reference;
+      typedef bool					const_reference;
+      typedef _Bit_reference*				pointer;
+      typedef const bool*				const_pointer;
+      typedef _Bit_iterator				iterator;
+      typedef _Bit_const_iterator			const_iterator;
+      typedef std::reverse_iterator<const_iterator>	const_reverse_iterator;
+      typedef std::reverse_iterator<iterator>		reverse_iterator;
+      typedef _Alloc					allocator_type;
+
+      _GLIBCXX20_CONSTEXPR
+      allocator_type
+      get_allocator() const
+      { return _Base::get_allocator(); }
+
+    protected:
+      using _Base::_M_allocate;
+      using _Base::_M_deallocate;
+      using _Base::_S_nword;
+      using _Base::_M_get_Bit_allocator;
+
+    public:
+#if __cplusplus >= 201103L
+      vector() = default;
+#else
+      vector() { }
+#endif
+
+      _GLIBCXX20_CONSTEXPR
+      explicit
+      vector(const allocator_type& __a)
+      : _Base(__a) { }
+
+#if __cplusplus >= 201103L
+      _GLIBCXX20_CONSTEXPR
+      explicit
+      vector(size_type __n, const allocator_type& __a = allocator_type())
+      : vector(__n, false, __a)
+      { }
+
+      _GLIBCXX20_CONSTEXPR
+      vector(size_type __n, const bool& __value,
+	     const allocator_type& __a = allocator_type())
+#else
+      explicit
+      vector(size_type __n, const bool& __value = bool(),
+	     const allocator_type& __a = allocator_type())
+#endif
+      : _Base(__a)
+      {
+	_M_initialize(__n);
+	_M_initialize_value(__value);
+      }
+
+      _GLIBCXX20_CONSTEXPR
+      vector(const vector& __x)
+      : _Base(_Bit_alloc_traits::_S_select_on_copy(__x._M_get_Bit_allocator()))
+      {
+	_M_initialize(__x.size());
+	_M_copy_aligned(__x.begin(), __x.end(), begin());
+      }
+
+#if __cplusplus >= 201103L
+      vector(vector&&) = default;
+
+    private:
+      _GLIBCXX20_CONSTEXPR
+      vector(vector&& __x, const allocator_type& __a, true_type) noexcept
+      : _Base(std::move(__x), __a)
+      { }
+
+      _GLIBCXX20_CONSTEXPR
+      vector(vector&& __x, const allocator_type& __a, false_type)
+      : _Base(__a)
+      {
+	if (__x.get_allocator() == __a)
+	  this->_M_move_data(std::move(__x));
+	else
+	  {
+	    _M_initialize(__x.size());
+	    _M_copy_aligned(__x.begin(), __x.end(), begin());
+	    __x.clear();
+	  }
+      }
+
+    public:
+      _GLIBCXX20_CONSTEXPR
+      vector(vector&& __x, const __type_identity_t<allocator_type>& __a)
+      noexcept(_Bit_alloc_traits::_S_always_equal())
+      : vector(std::move(__x), __a,
+	       typename _Bit_alloc_traits::is_always_equal{})
+      { }
+
+      _GLIBCXX20_CONSTEXPR
+      vector(const vector& __x, const __type_identity_t<allocator_type>& __a)
+      : _Base(__a)
+      {
+	_M_initialize(__x.size());
+	_M_copy_aligned(__x.begin(), __x.end(), begin());
+      }
+
+      _GLIBCXX20_CONSTEXPR
+      vector(initializer_list<bool> __l,
+	     const allocator_type& __a = allocator_type())
+      : _Base(__a)
+      {
+	_M_initialize_range(__l.begin(), __l.end(),
+			    random_access_iterator_tag());
+      }
+#endif
+
+#if __cplusplus >= 201103L
+      template<typename _InputIterator,
+	       typename = std::_RequireInputIter<_InputIterator>>
+	_GLIBCXX20_CONSTEXPR
+	vector(_InputIterator __first, _InputIterator __last,
+	       const allocator_type& __a = allocator_type())
+	: _Base(__a)
+	{
+	  _M_initialize_range(__first, __last,
+			      std::__iterator_category(__first));
+	}
+#else
+      template<typename _InputIterator>
+	vector(_InputIterator __first, _InputIterator __last,
+	       const allocator_type& __a = allocator_type())
+	: _Base(__a)
+	{
+	  // Check whether it's an integral type. If so, it's not an iterator.
+	  typedef typename std::__is_integer<_InputIterator>::__type _Integral;
+	  _M_initialize_dispatch(__first, __last, _Integral());
+	}
+#endif
+
+      _GLIBCXX20_CONSTEXPR
+      ~vector() _GLIBCXX_NOEXCEPT { }
+
+      _GLIBCXX20_CONSTEXPR
+      vector&
+      operator=(const vector& __x)
+      {
+	if (&__x == this)
+	  return *this;
+#if __cplusplus >= 201103L
+	if (_Bit_alloc_traits::_S_propagate_on_copy_assign())
+	  {
+	    if (this->_M_get_Bit_allocator() != __x._M_get_Bit_allocator())
+	      {
+		this->_M_deallocate();
+		std::__alloc_on_copy(_M_get_Bit_allocator(),
+				     __x._M_get_Bit_allocator());
+		_M_initialize(__x.size());
+	      }
+	    else
+	      std::__alloc_on_copy(_M_get_Bit_allocator(),
+				   __x._M_get_Bit_allocator());
+	  }
+#endif
+	if (__x.size() > capacity())
+	  {
+	    this->_M_deallocate();
+	    _M_initialize(__x.size());
+	  }
+	this->_M_impl._M_finish = _M_copy_aligned(__x.begin(), __x.end(),
+						  begin());
+	return *this;
+      }
+
+#if __cplusplus >= 201103L
+      _GLIBCXX20_CONSTEXPR
+      vector&
+      operator=(vector&& __x) noexcept(_Bit_alloc_traits::_S_nothrow_move())
+      {
+	if (_Bit_alloc_traits::_S_propagate_on_move_assign()
+	    || this->_M_get_Bit_allocator() == __x._M_get_Bit_allocator())
+	  {
+	    this->_M_deallocate();
+	    this->_M_move_data(std::move(__x));
+	    std::__alloc_on_move(_M_get_Bit_allocator(),
+				 __x._M_get_Bit_allocator());
+	  }
+	else
+	  {
+	    if (__x.size() > capacity())
+	      {
+		this->_M_deallocate();
+		_M_initialize(__x.size());
+	      }
+	    this->_M_impl._M_finish = _M_copy_aligned(__x.begin(), __x.end(),
+						      begin());
+	    __x.clear();
+	  }
+	return *this;
+      }
+
+      _GLIBCXX20_CONSTEXPR
+      vector&
+      operator=(initializer_list<bool> __l)
+      {
+	this->assign(__l.begin(), __l.end());
+	return *this;
+      }
+#endif
+
+      // assign(), a generalized assignment member function.  Two
+      // versions: one that takes a count, and one that takes a range.
+      // The range version is a member template, so we dispatch on whether
+      // or not the type is an integer.
+      _GLIBCXX20_CONSTEXPR
+      void
+      assign(size_type __n, const bool& __x)
+      { _M_fill_assign(__n, __x); }
+
+#if __cplusplus >= 201103L
+      template<typename _InputIterator,
+	       typename = std::_RequireInputIter<_InputIterator>>
+	_GLIBCXX20_CONSTEXPR
+	void
+	assign(_InputIterator __first, _InputIterator __last)
+	{ _M_assign_aux(__first, __last, std::__iterator_category(__first)); }
+#else
+      template<typename _InputIterator>
+	void
+	assign(_InputIterator __first, _InputIterator __last)
+	{
+	  // Check whether it's an integral type. If so, it's not an iterator.
+	  typedef typename std::__is_integer<_InputIterator>::__type _Integral;
+	  _M_assign_dispatch(__first, __last, _Integral());
+	}
+#endif
+
+#if __cplusplus >= 201103L
+      _GLIBCXX20_CONSTEXPR
+      void
+      assign(initializer_list<bool> __l)
+      { _M_assign_aux(__l.begin(), __l.end(), random_access_iterator_tag()); }
+#endif
+
+      _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
+      iterator
+      begin() _GLIBCXX_NOEXCEPT
+      { return iterator(this->_M_impl._M_start._M_p, 0); }
+
+      _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
+      const_iterator
+      begin() const _GLIBCXX_NOEXCEPT
+      { return const_iterator(this->_M_impl._M_start._M_p, 0); }
+
+      _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
+      iterator
+      end() _GLIBCXX_NOEXCEPT
+      { return this->_M_impl._M_finish; }
+
+      _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
+      const_iterator
+      end() const _GLIBCXX_NOEXCEPT
+      { return this->_M_impl._M_finish; }
+
+      _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
+      reverse_iterator
+      rbegin() _GLIBCXX_NOEXCEPT
+      { return reverse_iterator(end()); }
+
+      _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
+      const_reverse_iterator
+      rbegin() const _GLIBCXX_NOEXCEPT
+      { return const_reverse_iterator(end()); }
+
+      _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
+      reverse_iterator
+      rend() _GLIBCXX_NOEXCEPT
+      { return reverse_iterator(begin()); }
+
+      _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
+      const_reverse_iterator
+      rend() const _GLIBCXX_NOEXCEPT
+      { return const_reverse_iterator(begin()); }
+
+#if __cplusplus >= 201103L
+      [[__nodiscard__]] _GLIBCXX20_CONSTEXPR
+      const_iterator
+      cbegin() const noexcept
+      { return const_iterator(this->_M_impl._M_start._M_p, 0); }
+
+      [[__nodiscard__]] _GLIBCXX20_CONSTEXPR
+      const_iterator
+      cend() const noexcept
+      { return this->_M_impl._M_finish; }
+
+      [[__nodiscard__]] _GLIBCXX20_CONSTEXPR
+      const_reverse_iterator
+      crbegin() const noexcept
+      { return const_reverse_iterator(end()); }
+
+      [[__nodiscard__]] _GLIBCXX20_CONSTEXPR
+      const_reverse_iterator
+      crend() const noexcept
+      { return const_reverse_iterator(begin()); }
+#endif
+
+      _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
+      size_type
+      size() const _GLIBCXX_NOEXCEPT
+      { return size_type(end() - begin()); }
+
+      _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
+      size_type
+      max_size() const _GLIBCXX_NOEXCEPT
+      {
+	const size_type __isize =
+	  __gnu_cxx::__numeric_traits<difference_type>::__max
+	  - int(_S_word_bit) + 1;
+	const size_type __asize
+	  = _Bit_alloc_traits::max_size(_M_get_Bit_allocator());
+	return (__asize <= __isize / int(_S_word_bit)
+		? __asize * int(_S_word_bit) : __isize);
+      }
+
+      _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
+      size_type
+      capacity() const _GLIBCXX_NOEXCEPT
+      { return size_type(const_iterator(this->_M_impl._M_end_addr(), 0)
+			 - begin()); }
+
+      _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
+      bool
+      empty() const _GLIBCXX_NOEXCEPT
+      { return begin() == end(); }
+
+      _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
+      reference
+      operator[](size_type __n)
+      { return begin()[__n]; }
+
+      _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
+      const_reference
+      operator[](size_type __n) const
+      { return begin()[__n]; }
+
+    protected:
+      _GLIBCXX20_CONSTEXPR
+      void
+      _M_range_check(size_type __n) const
+      {
+	if (__n >= this->size())
+	  __throw_out_of_range_fmt(__N("vector<bool>::_M_range_check: __n "
+				       "(which is %zu) >= this->size() "
+				       "(which is %zu)"),
+				   __n, this->size());
+      }
+
+    public:
+      _GLIBCXX20_CONSTEXPR
+      reference
+      at(size_type __n)
+      {
+	_M_range_check(__n);
+	return (*this)[__n];
+      }
+
+      _GLIBCXX20_CONSTEXPR
+      const_reference
+      at(size_type __n) const
+      {
+	_M_range_check(__n);
+	return (*this)[__n];
+      }
+
+      _GLIBCXX20_CONSTEXPR
+      void
+      reserve(size_type __n)
+      {
+	if (__n > max_size())
+	  __throw_length_error(__N("vector::reserve"));
+	if (capacity() < __n)
+	  _M_reallocate(__n);
+      }
+
+      _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
+      reference
+      front()
+      { return *begin(); }
+
+      _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
+      const_reference
+      front() const
+      { return *begin(); }
+
+      _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
+      reference
+      back()
+      { return *(end() - 1); }
+
+      _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
+      const_reference
+      back() const
+      { return *(end() - 1); }
+
+      _GLIBCXX20_CONSTEXPR
+      void
+      push_back(bool __x)
+      {
+	if (this->_M_impl._M_finish._M_p != this->_M_impl._M_end_addr())
+	  *this->_M_impl._M_finish++ = __x;
+	else
+	  _M_insert_aux(end(), __x);
+      }
+
+      _GLIBCXX20_CONSTEXPR
+      void
+      swap(vector& __x) _GLIBCXX_NOEXCEPT
+      {
+#if __cplusplus >= 201103L
+	__glibcxx_assert(_Bit_alloc_traits::propagate_on_container_swap::value
+			 || _M_get_Bit_allocator() == __x._M_get_Bit_allocator());
+#endif
+	this->_M_impl._M_swap_data(__x._M_impl);
+	_Bit_alloc_traits::_S_on_swap(_M_get_Bit_allocator(),
+				      __x._M_get_Bit_allocator());
+      }
+
+      // [23.2.5]/1, third-to-last entry in synopsis listing
+      _GLIBCXX20_CONSTEXPR
+      static void
+      swap(reference __x, reference __y) _GLIBCXX_NOEXCEPT
+      {
+	bool __tmp = __x;
+	__x = __y;
+	__y = __tmp;
+      }
+
+      _GLIBCXX20_CONSTEXPR
+      iterator
+#if __cplusplus >= 201103L
+      insert(const_iterator __position, const bool& __x)
+#else
+      insert(iterator __position, const bool& __x)
+#endif
+      {
+	const difference_type __n = __position - begin();
+	if (this->_M_impl._M_finish._M_p != this->_M_impl._M_end_addr()
+	    && __position == end())
+	  *this->_M_impl._M_finish++ = __x;
+	else
+	  _M_insert_aux(__position._M_const_cast(), __x);
+	return begin() + __n;
+      }
+
+#if _GLIBCXX_USE_DEPRECATED
+      _GLIBCXX_DEPRECATED_SUGGEST("insert(position, false)")
+      iterator
+      insert(const_iterator __position)
+      { return this->insert(__position._M_const_cast(), false); }
+#endif
+
+#if __cplusplus >= 201103L
+      template<typename _InputIterator,
+	       typename = std::_RequireInputIter<_InputIterator>>
+	_GLIBCXX20_CONSTEXPR
+	iterator
+	insert(const_iterator __position,
+	       _InputIterator __first, _InputIterator __last)
+	{
+	  difference_type __offset = __position - cbegin();
+	  _M_insert_range(__position._M_const_cast(),
+			  __first, __last,
+			  std::__iterator_category(__first));
+	  return begin() + __offset;
+	}
+#else
+      template<typename _InputIterator>
+	void
+	insert(iterator __position,
+	       _InputIterator __first, _InputIterator __last)
+	{
+	  // Check whether it's an integral type. If so, it's not an iterator.
+	  typedef typename std::__is_integer<_InputIterator>::__type _Integral;
+	  _M_insert_dispatch(__position, __first, __last, _Integral());
+	}
+#endif
+
+#if __cplusplus >= 201103L
+      _GLIBCXX20_CONSTEXPR
+      iterator
+      insert(const_iterator __position, size_type __n, const bool& __x)
+      {
+	difference_type __offset = __position - cbegin();
+	_M_fill_insert(__position._M_const_cast(), __n, __x);
+	return begin() + __offset;
+      }
+#else
+      void
+      insert(iterator __position, size_type __n, const bool& __x)
+      { _M_fill_insert(__position, __n, __x); }
+#endif
+
+#if __cplusplus >= 201103L
+      _GLIBCXX20_CONSTEXPR
+      iterator
+      insert(const_iterator __p, initializer_list<bool> __l)
+      { return this->insert(__p, __l.begin(), __l.end()); }
+#endif
+
+      _GLIBCXX20_CONSTEXPR
+      void
+      pop_back()
+      { --this->_M_impl._M_finish; }
+
+      _GLIBCXX20_CONSTEXPR
+      iterator
+#if __cplusplus >= 201103L
+      erase(const_iterator __position)
+#else
+      erase(iterator __position)
+#endif
+      { return _M_erase(__position._M_const_cast()); }
+
+      _GLIBCXX20_CONSTEXPR
+      iterator
+#if __cplusplus >= 201103L
+      erase(const_iterator __first, const_iterator __last)
+#else
+      erase(iterator __first, iterator __last)
+#endif
+      { return _M_erase(__first._M_const_cast(), __last._M_const_cast()); }
+
+      _GLIBCXX20_CONSTEXPR
+      void
+      resize(size_type __new_size, bool __x = bool())
+      {
+	if (__new_size < size())
+	  _M_erase_at_end(begin() + difference_type(__new_size));
+	else
+	  insert(end(), __new_size - size(), __x);
+      }
+
+#if __cplusplus >= 201103L
+      _GLIBCXX20_CONSTEXPR
+      void
+      shrink_to_fit()
+      { _M_shrink_to_fit(); }
+#endif
+
+      _GLIBCXX20_CONSTEXPR
+      void
+      flip() _GLIBCXX_NOEXCEPT
+      {
+	_Bit_type * const __end = this->_M_impl._M_end_addr();
+	for (_Bit_type * __p = this->_M_impl._M_start._M_p; __p != __end; ++__p)
+	  *__p = ~*__p;
+      }
+
+      _GLIBCXX20_CONSTEXPR
+      void
+      clear() _GLIBCXX_NOEXCEPT
+      { _M_erase_at_end(begin()); }
+
+#if __cplusplus >= 201103L
+      template<typename... _Args>
+#if __cplusplus > 201402L
+	_GLIBCXX20_CONSTEXPR
+	reference
+#else
+	void
+#endif
+	emplace_back(_Args&&... __args)
+	{
+	  push_back(bool(__args...));
+#if __cplusplus > 201402L
+	  return back();
+#endif
+	}
+
+      template<typename... _Args>
+	_GLIBCXX20_CONSTEXPR
+	iterator
+	emplace(const_iterator __pos, _Args&&... __args)
+	{ return insert(__pos, bool(__args...)); }
+#endif
+
+    protected:
+      // Precondition: __first._M_offset == 0 && __result._M_offset == 0.
+      _GLIBCXX20_CONSTEXPR
+      iterator
+      _M_copy_aligned(const_iterator __first, const_iterator __last,
+		      iterator __result)
+      {
+	_Bit_type* __q = std::copy(__first._M_p, __last._M_p, __result._M_p);
+	return std::copy(const_iterator(__last._M_p, 0), __last,
+			 iterator(__q, 0));
+      }
+
+      _GLIBCXX20_CONSTEXPR
+      void
+      _M_initialize(size_type __n)
+      {
+	if (__n)
+	  {
+	    _Bit_pointer __q = this->_M_allocate(__n);
+	    this->_M_impl._M_end_of_storage = __q + _S_nword(__n);
+	    iterator __start = iterator(std::__addressof(*__q), 0);
+	    this->_M_impl._M_start = __start;
+	    this->_M_impl._M_finish = __start + difference_type(__n);
+	  }
+      }
+
+      _GLIBCXX20_CONSTEXPR
+      void
+      _M_initialize_value(bool __x) _GLIBCXX_NOEXCEPT
+      {
+	if (_Bit_type* __p = this->_M_impl._M_start._M_p)
+	  __fill_bvector_n(__p, this->_M_impl._M_end_addr() - __p, __x);
+      }
+
+      _GLIBCXX20_CONSTEXPR
+      void
+      _M_reallocate(size_type __n);
+
+#if __cplusplus >= 201103L
+      _GLIBCXX20_CONSTEXPR
+      bool
+      _M_shrink_to_fit();
+#endif
+
+#if __cplusplus < 201103L
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 438. Ambiguity in the "do the right thing" clause
+      template<typename _Integer>
+	void
+	_M_initialize_dispatch(_Integer __n, _Integer __x, __true_type)
+	{
+	  _M_initialize(static_cast<size_type>(__n));
+	  _M_initialize_value(__x);
+	}
+
+      template<typename _InputIterator>
+	void
+	_M_initialize_dispatch(_InputIterator __first, _InputIterator __last,
+			       __false_type)
+	{ _M_initialize_range(__first, __last,
+			      std::__iterator_category(__first)); }
+#endif
+
+      template<typename _InputIterator>
+	_GLIBCXX20_CONSTEXPR
+	void
+	_M_initialize_range(_InputIterator __first, _InputIterator __last,
+			    std::input_iterator_tag)
+	{
+	  for (; __first != __last; ++__first)
+	    push_back(*__first);
+	}
+
+      template<typename _ForwardIterator>
+	_GLIBCXX20_CONSTEXPR
+	void
+	_M_initialize_range(_ForwardIterator __first, _ForwardIterator __last,
+			    std::forward_iterator_tag)
+	{
+	  const size_type __n = std::distance(__first, __last);
+	  _M_initialize(__n);
+	  std::copy(__first, __last, begin());
+	}
+
+#if __cplusplus < 201103L
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 438. Ambiguity in the "do the right thing" clause
+      template<typename _Integer>
+	void
+	_M_assign_dispatch(_Integer __n, _Integer __val, __true_type)
+	{ _M_fill_assign(__n, __val); }
+
+      template<class _InputIterator>
+	void
+	_M_assign_dispatch(_InputIterator __first, _InputIterator __last,
+			   __false_type)
+	{ _M_assign_aux(__first, __last, std::__iterator_category(__first)); }
+#endif
+
+      _GLIBCXX20_CONSTEXPR
+      void
+      _M_fill_assign(size_t __n, bool __x)
+      {
+	if (__n > size())
+	  {
+	    _M_initialize_value(__x);
+	    insert(end(), __n - size(), __x);
+	  }
+	else
+	  {
+	    _M_erase_at_end(begin() + __n);
+	    _M_initialize_value(__x);
+	  }
+      }
+
+      template<typename _InputIterator>
+	_GLIBCXX20_CONSTEXPR
+	void
+	_M_assign_aux(_InputIterator __first, _InputIterator __last,
+		      std::input_iterator_tag)
+	{
+	  iterator __cur = begin();
+	  for (; __first != __last && __cur != end(); ++__cur, (void)++__first)
+	    *__cur = *__first;
+	  if (__first == __last)
+	    _M_erase_at_end(__cur);
+	  else
+	    insert(end(), __first, __last);
+	}
+
+      template<typename _ForwardIterator>
+	_GLIBCXX20_CONSTEXPR
+	void
+	_M_assign_aux(_ForwardIterator __first, _ForwardIterator __last,
+		      std::forward_iterator_tag)
+	{
+	  const size_type __len = std::distance(__first, __last);
+	  if (__len < size())
+	    _M_erase_at_end(std::copy(__first, __last, begin()));
+	  else
+	    {
+	      _ForwardIterator __mid = __first;
+	      std::advance(__mid, size());
+	      std::copy(__first, __mid, begin());
+	      insert(end(), __mid, __last);
+	    }
+	}
+
+#if __cplusplus < 201103L
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 438. Ambiguity in the "do the right thing" clause
+      template<typename _Integer>
+	void
+	_M_insert_dispatch(iterator __pos, _Integer __n, _Integer __x,
+			   __true_type)
+	{ _M_fill_insert(__pos, __n, __x); }
+
+      template<typename _InputIterator>
+	void
+	_M_insert_dispatch(iterator __pos,
+			   _InputIterator __first, _InputIterator __last,
+			   __false_type)
+	{ _M_insert_range(__pos, __first, __last,
+			  std::__iterator_category(__first)); }
+#endif
+
+      _GLIBCXX20_CONSTEXPR
+      void
+      _M_fill_insert(iterator __position, size_type __n, bool __x);
+
+      template<typename _InputIterator>
+	_GLIBCXX20_CONSTEXPR
+	void
+	_M_insert_range(iterator __pos, _InputIterator __first,
+			_InputIterator __last, std::input_iterator_tag)
+	{
+	  for (; __first != __last; ++__first)
+	    {
+	      __pos = insert(__pos, *__first);
+	      ++__pos;
+	    }
+	}
+
+      template<typename _ForwardIterator>
+	_GLIBCXX20_CONSTEXPR
+	void
+	_M_insert_range(iterator __position, _ForwardIterator __first,
+			_ForwardIterator __last, std::forward_iterator_tag);
+
+      _GLIBCXX20_CONSTEXPR
+      void
+      _M_insert_aux(iterator __position, bool __x);
+
+      _GLIBCXX20_CONSTEXPR
+      size_type
+      _M_check_len(size_type __n, const char* __s) const
+      {
+	if (max_size() - size() < __n)
+	  __throw_length_error(__N(__s));
+
+	const size_type __len = size() + std::max(size(), __n);
+	return (__len < size() || __len > max_size()) ? max_size() : __len;
+      }
+
+      _GLIBCXX20_CONSTEXPR
+      void
+      _M_erase_at_end(iterator __pos)
+      { this->_M_impl._M_finish = __pos; }
+
+      _GLIBCXX20_CONSTEXPR
+      iterator
+      _M_erase(iterator __pos);
+
+      _GLIBCXX20_CONSTEXPR
+      iterator
+      _M_erase(iterator __first, iterator __last);
+
+    protected:
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // DR 464. Suggestion for new member functions in standard containers.
+      // N.B. DR 464 says nothing about vector<bool> but we need something
+      // here due to the using-declaration in __gnu_debug::vector.
+      // vector class.
+#if __cplusplus >= 201103L
+      void data() = delete;
+#else
+      void data() { }
+#endif
+    };
+
+_GLIBCXX_END_NAMESPACE_CONTAINER
+
+  // Fill a partial word.
+  _GLIBCXX20_CONSTEXPR
+  inline void
+  __fill_bvector(_Bit_type* __v, unsigned int __first, unsigned int __last,
+		 bool __x) _GLIBCXX_NOEXCEPT
+  {
+    const _Bit_type __fmask = ~0ul << __first;
+    const _Bit_type __lmask = ~0ul >> (_S_word_bit - __last);
+    const _Bit_type __mask = __fmask & __lmask;
+
+    if (__x)
+      *__v |= __mask;
+    else
+      *__v &= ~__mask;
+  }
+
+  // Fill N full words, as if using memset, but usable in constant expressions.
+  __attribute__((__nonnull__))
+  _GLIBCXX20_CONSTEXPR
+  inline void
+  __fill_bvector_n(_Bit_type* __p, size_t __n, bool __x) _GLIBCXX_NOEXCEPT
+  {
+#if __cpp_lib_is_constant_evaluated
+    if (std::is_constant_evaluated())
+    {
+      for (size_t __i = 0; __i < __n; ++__i)
+	__p[__i] = __x ? ~0ul : 0ul;
+      return;
+    }
+#endif
+    __builtin_memset(__p, __x ? ~0 : 0, __n * sizeof(_Bit_type));
+  }
+
+
+  _GLIBCXX20_CONSTEXPR
+  inline void
+  __fill_a1(_GLIBCXX_STD_C::_Bit_iterator __first,
+	    _GLIBCXX_STD_C::_Bit_iterator __last, const bool& __x)
+  {
+    if (__first._M_p != __last._M_p)
+      {
+	_Bit_type* __first_p = __first._M_p;
+	if (__first._M_offset != 0)
+	  __fill_bvector(__first_p++, __first._M_offset, _S_word_bit, __x);
+
+	__fill_bvector_n(__first_p, __last._M_p - __first_p, __x);
+
+	if (__last._M_offset != 0)
+	  __fill_bvector(__last._M_p, 0, __last._M_offset, __x);
+      }
+    else if (__first._M_offset != __last._M_offset)
+      __fill_bvector(__first._M_p, __first._M_offset, __last._M_offset, __x);
+  }
+
+#if __cplusplus >= 201103L
+  // DR 1182.
+  /// std::hash specialization for vector<bool>.
+  template<typename _Alloc>
+    struct hash<_GLIBCXX_STD_C::vector<bool, _Alloc>>
+    : public __hash_base<size_t, _GLIBCXX_STD_C::vector<bool, _Alloc>>
+    {
+      size_t
+      operator()(const _GLIBCXX_STD_C::vector<bool, _Alloc>&) const noexcept;
+    };
+#endif // C++11
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stl_bvector.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stl_bvector.h.blob
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Binary files /dev/null and b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stl_bvector.h.blob differ
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stl_construct.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stl_construct.h
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--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stl_construct.h
@@ -0,0 +1,267 @@
+// nonstandard construct and destroy functions -*- C++ -*-
+
+// Copyright (C) 2001-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/*
+ *
+ * Copyright (c) 1994
+ * Hewlett-Packard Company
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Hewlett-Packard Company makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ *
+ *
+ * Copyright (c) 1996,1997
+ * Silicon Graphics Computer Systems, Inc.
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Silicon Graphics makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ */
+
+/** @file bits/stl_construct.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{memory}
+ */
+
+#ifndef _STL_CONSTRUCT_H
+#define _STL_CONSTRUCT_H 1
+
+#include <new>
+#include <bits/move.h>
+#include <bits/stl_iterator_base_types.h> // for iterator_traits
+#include <bits/stl_iterator_base_funcs.h> // for advance
+
+/* This file provides the C++17 functions std::destroy_at, std::destroy, and
+ * std::destroy_n, and the C++20 function std::construct_at.
+ * It also provides std::_Construct, std::_Destroy,and std::_Destroy_n functions
+ * which are defined in all standard modes and so can be used in C++98-14 code.
+ * The _Destroy functions will dispatch to destroy_at during constant
+ * evaluation, because calls to that function are intercepted by the compiler
+ * to allow use in constant expressions.
+ */
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+#if __cplusplus >= 201703L
+  template <typename _Tp>
+    _GLIBCXX20_CONSTEXPR inline void
+    destroy_at(_Tp* __location)
+    {
+      if constexpr (__cplusplus > 201703L && is_array_v<_Tp>)
+	{
+	  for (auto& __x : *__location)
+	    std::destroy_at(std::__addressof(__x));
+	}
+      else
+	__location->~_Tp();
+    }
+
+#if __cplusplus >= 202002L
+  template<typename _Tp, typename... _Args>
+    constexpr auto
+    construct_at(_Tp* __location, _Args&&... __args)
+    noexcept(noexcept(::new((void*)0) _Tp(std::declval<_Args>()...)))
+    -> decltype(::new((void*)0) _Tp(std::declval<_Args>()...))
+    { return ::new((void*)__location) _Tp(std::forward<_Args>(__args)...); }
+#endif // C++20
+#endif// C++17
+
+  /**
+   * Constructs an object in existing memory by invoking an allocated
+   * object's constructor with an initializer.
+   */
+#if __cplusplus >= 201103L
+  template<typename _Tp, typename... _Args>
+    _GLIBCXX20_CONSTEXPR
+    inline void
+    _Construct(_Tp* __p, _Args&&... __args)
+    {
+#if __cplusplus >= 202002L
+      if (std::__is_constant_evaluated())
+	{
+	  // Allow std::_Construct to be used in constant expressions.
+	  std::construct_at(__p, std::forward<_Args>(__args)...);
+	  return;
+	}
+#endif
+      ::new((void*)__p) _Tp(std::forward<_Args>(__args)...);
+    }
+#else
+  template<typename _T1, typename _T2>
+    inline void
+    _Construct(_T1* __p, const _T2& __value)
+    {
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 402. wrong new expression in [some_]allocator::construct
+      ::new(static_cast<void*>(__p)) _T1(__value);
+    }
+#endif
+
+  template<typename _T1>
+    inline void
+    _Construct_novalue(_T1* __p)
+    { ::new((void*)__p) _T1; }
+
+  template<typename _ForwardIterator>
+    _GLIBCXX20_CONSTEXPR void
+    _Destroy(_ForwardIterator __first, _ForwardIterator __last);
+
+  /**
+   * Destroy the object pointed to by a pointer type.
+   */
+  template<typename _Tp>
+    _GLIBCXX14_CONSTEXPR inline void
+    _Destroy(_Tp* __pointer)
+    {
+#if __cplusplus > 201703L
+      std::destroy_at(__pointer);
+#else
+      __pointer->~_Tp();
+#endif
+    }
+
+  template<bool>
+    struct _Destroy_aux
+    {
+      template<typename _ForwardIterator>
+	static _GLIBCXX20_CONSTEXPR void
+	__destroy(_ForwardIterator __first, _ForwardIterator __last)
+	{
+	  for (; __first != __last; ++__first)
+	    std::_Destroy(std::__addressof(*__first));
+	}
+    };
+
+  template<>
+    struct _Destroy_aux<true>
+    {
+      template<typename _ForwardIterator>
+        static void
+        __destroy(_ForwardIterator, _ForwardIterator) { }
+    };
+
+  /**
+   * Destroy a range of objects.  If the value_type of the object has
+   * a trivial destructor, the compiler should optimize all of this
+   * away, otherwise the objects' destructors must be invoked.
+   */
+  template<typename _ForwardIterator>
+    _GLIBCXX20_CONSTEXPR inline void
+    _Destroy(_ForwardIterator __first, _ForwardIterator __last)
+    {
+      typedef typename iterator_traits<_ForwardIterator>::value_type
+                       _Value_type;
+#if __cplusplus >= 201103L
+      // A deleted destructor is trivial, this ensures we reject such types:
+      static_assert(is_destructible<_Value_type>::value,
+		    "value type is destructible");
+#endif
+#if __cplusplus >= 202002L
+      if (std::__is_constant_evaluated())
+	return _Destroy_aux<false>::__destroy(__first, __last);
+#endif
+      std::_Destroy_aux<__has_trivial_destructor(_Value_type)>::
+	__destroy(__first, __last);
+    }
+
+  template<bool>
+    struct _Destroy_n_aux
+    {
+      template<typename _ForwardIterator, typename _Size>
+	static _GLIBCXX20_CONSTEXPR _ForwardIterator
+	__destroy_n(_ForwardIterator __first, _Size __count)
+	{
+	  for (; __count > 0; (void)++__first, --__count)
+	    std::_Destroy(std::__addressof(*__first));
+	  return __first;
+	}
+    };
+
+  template<>
+    struct _Destroy_n_aux<true>
+    {
+      template<typename _ForwardIterator, typename _Size>
+        static _ForwardIterator
+        __destroy_n(_ForwardIterator __first, _Size __count)
+	{
+	  std::advance(__first, __count);
+	  return __first;
+	}
+    };
+
+  /**
+   * Destroy a range of objects.  If the value_type of the object has
+   * a trivial destructor, the compiler should optimize all of this
+   * away, otherwise the objects' destructors must be invoked.
+   */
+  template<typename _ForwardIterator, typename _Size>
+    _GLIBCXX20_CONSTEXPR inline _ForwardIterator
+    _Destroy_n(_ForwardIterator __first, _Size __count)
+    {
+      typedef typename iterator_traits<_ForwardIterator>::value_type
+                       _Value_type;
+#if __cplusplus >= 201103L
+      // A deleted destructor is trivial, this ensures we reject such types:
+      static_assert(is_destructible<_Value_type>::value,
+		    "value type is destructible");
+#endif
+#if __cplusplus >= 202002L
+      if (std::__is_constant_evaluated())
+	return _Destroy_n_aux<false>::__destroy_n(__first, __count);
+#endif
+      return std::_Destroy_n_aux<__has_trivial_destructor(_Value_type)>::
+	__destroy_n(__first, __count);
+    }
+
+#if __cplusplus >= 201703L
+  template <typename _ForwardIterator>
+    _GLIBCXX20_CONSTEXPR inline void
+    destroy(_ForwardIterator __first, _ForwardIterator __last)
+    {
+      std::_Destroy(__first, __last);
+    }
+
+  template <typename _ForwardIterator, typename _Size>
+    _GLIBCXX20_CONSTEXPR inline _ForwardIterator
+    destroy_n(_ForwardIterator __first, _Size __count)
+    {
+      return std::_Destroy_n(__first, __count);
+    }
+#endif // C++17
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif /* _STL_CONSTRUCT_H */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stl_construct.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stl_construct.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stl_deque.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stl_deque.h
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stl_deque.h
@@ -0,0 +1,2385 @@
+// Deque implementation -*- C++ -*-
+
+// Copyright (C) 2001-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/*
+ *
+ * Copyright (c) 1994
+ * Hewlett-Packard Company
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Hewlett-Packard Company makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ *
+ *
+ * Copyright (c) 1997
+ * Silicon Graphics Computer Systems, Inc.
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Silicon Graphics makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ */
+
+/** @file bits/stl_deque.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{deque}
+ */
+
+#ifndef _STL_DEQUE_H
+#define _STL_DEQUE_H 1
+
+#include <bits/concept_check.h>
+#include <bits/stl_iterator_base_types.h>
+#include <bits/stl_iterator_base_funcs.h>
+#if __cplusplus >= 201103L
+#include <initializer_list>
+#include <bits/stl_uninitialized.h> // for __is_bitwise_relocatable
+#endif
+#if __cplusplus > 201703L
+# include <compare>
+#endif
+
+#include <debug/assertions.h>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+_GLIBCXX_BEGIN_NAMESPACE_CONTAINER
+
+  /**
+   *  @brief This function controls the size of memory nodes.
+   *  @param  __size  The size of an element.
+   *  @return   The number (not byte size) of elements per node.
+   *
+   *  This function started off as a compiler kludge from SGI, but
+   *  seems to be a useful wrapper around a repeated constant
+   *  expression.  The @b 512 is tunable (and no other code needs to
+   *  change), but no investigation has been done since inheriting the
+   *  SGI code.  Touch _GLIBCXX_DEQUE_BUF_SIZE only if you know what
+   *  you are doing, however: changing it breaks the binary
+   *  compatibility!!
+  */
+
+#ifndef _GLIBCXX_DEQUE_BUF_SIZE
+#define _GLIBCXX_DEQUE_BUF_SIZE 512
+#endif
+
+  _GLIBCXX_CONSTEXPR inline size_t
+  __deque_buf_size(size_t __size)
+  { return (__size < _GLIBCXX_DEQUE_BUF_SIZE
+	    ? size_t(_GLIBCXX_DEQUE_BUF_SIZE / __size) : size_t(1)); }
+
+
+  /**
+   *  @brief A deque::iterator.
+   *
+   *  Quite a bit of intelligence here.  Much of the functionality of
+   *  deque is actually passed off to this class.  A deque holds two
+   *  of these internally, marking its valid range.  Access to
+   *  elements is done as offsets of either of those two, relying on
+   *  operator overloading in this class.
+   *
+   *  All the functions are op overloads except for _M_set_node.
+  */
+  template<typename _Tp, typename _Ref, typename _Ptr>
+    struct _Deque_iterator
+    {
+#if __cplusplus < 201103L
+      typedef _Deque_iterator<_Tp, _Tp&, _Tp*>		   iterator;
+      typedef _Deque_iterator<_Tp, const _Tp&, const _Tp*> const_iterator;
+      typedef _Tp*					   _Elt_pointer;
+      typedef _Tp**					   _Map_pointer;
+#else
+    private:
+      template<typename _CvTp>
+	using __iter = _Deque_iterator<_Tp, _CvTp&, __ptr_rebind<_Ptr, _CvTp>>;
+    public:
+      typedef __iter<_Tp>				   iterator;
+      typedef __iter<const _Tp>				   const_iterator;
+      typedef __ptr_rebind<_Ptr, _Tp>			   _Elt_pointer;
+      typedef __ptr_rebind<_Ptr, _Elt_pointer>		   _Map_pointer;
+#endif
+
+      static size_t _S_buffer_size() _GLIBCXX_NOEXCEPT
+      { return __deque_buf_size(sizeof(_Tp)); }
+
+      typedef std::random_access_iterator_tag	iterator_category;
+      typedef _Tp				value_type;
+      typedef _Ptr				pointer;
+      typedef _Ref				reference;
+      typedef size_t				size_type;
+      typedef ptrdiff_t				difference_type;
+      typedef _Deque_iterator			_Self;
+
+      _Elt_pointer _M_cur;
+      _Elt_pointer _M_first;
+      _Elt_pointer _M_last;
+      _Map_pointer _M_node;
+
+      _Deque_iterator(_Elt_pointer __x, _Map_pointer __y) _GLIBCXX_NOEXCEPT
+      : _M_cur(__x), _M_first(*__y),
+	_M_last(*__y + _S_buffer_size()), _M_node(__y) { }
+
+      _Deque_iterator() _GLIBCXX_NOEXCEPT
+      : _M_cur(), _M_first(), _M_last(), _M_node() { }
+
+#if __cplusplus < 201103L
+      // Conversion from iterator to const_iterator.
+      _Deque_iterator(const iterator& __x) _GLIBCXX_NOEXCEPT
+      : _M_cur(__x._M_cur), _M_first(__x._M_first),
+	_M_last(__x._M_last), _M_node(__x._M_node) { }
+#else
+      // Conversion from iterator to const_iterator.
+      template<typename _Iter,
+	       typename = _Require<is_same<_Self, const_iterator>,
+				   is_same<_Iter, iterator>>>
+       _Deque_iterator(const _Iter& __x) noexcept
+       : _M_cur(__x._M_cur), _M_first(__x._M_first),
+	 _M_last(__x._M_last), _M_node(__x._M_node) { }
+
+      _Deque_iterator(const _Deque_iterator& __x) noexcept
+       : _M_cur(__x._M_cur), _M_first(__x._M_first),
+	 _M_last(__x._M_last), _M_node(__x._M_node) { }
+
+      _Deque_iterator& operator=(const _Deque_iterator&) = default;
+#endif
+
+      iterator
+      _M_const_cast() const _GLIBCXX_NOEXCEPT
+      { return iterator(_M_cur, _M_node); }
+
+      _GLIBCXX_NODISCARD
+      reference
+      operator*() const _GLIBCXX_NOEXCEPT
+      { return *_M_cur; }
+
+      _GLIBCXX_NODISCARD
+      pointer
+      operator->() const _GLIBCXX_NOEXCEPT
+      { return _M_cur; }
+
+      _Self&
+      operator++() _GLIBCXX_NOEXCEPT
+      {
+	++_M_cur;
+	if (_M_cur == _M_last)
+	  {
+	    _M_set_node(_M_node + 1);
+	    _M_cur = _M_first;
+	  }
+	return *this;
+      }
+
+      _Self
+      operator++(int) _GLIBCXX_NOEXCEPT
+      {
+	_Self __tmp = *this;
+	++*this;
+	return __tmp;
+      }
+
+      _Self&
+      operator--() _GLIBCXX_NOEXCEPT
+      {
+	if (_M_cur == _M_first)
+	  {
+	    _M_set_node(_M_node - 1);
+	    _M_cur = _M_last;
+	  }
+	--_M_cur;
+	return *this;
+      }
+
+      _Self
+      operator--(int) _GLIBCXX_NOEXCEPT
+      {
+	_Self __tmp = *this;
+	--*this;
+	return __tmp;
+      }
+
+      _Self&
+      operator+=(difference_type __n) _GLIBCXX_NOEXCEPT
+      {
+	const difference_type __offset = __n + (_M_cur - _M_first);
+	if (__offset >= 0 && __offset < difference_type(_S_buffer_size()))
+	  _M_cur += __n;
+	else
+	  {
+	    const difference_type __node_offset =
+	      __offset > 0 ? __offset / difference_type(_S_buffer_size())
+			   : -difference_type((-__offset - 1)
+					      / _S_buffer_size()) - 1;
+	    _M_set_node(_M_node + __node_offset);
+	    _M_cur = _M_first + (__offset - __node_offset
+				 * difference_type(_S_buffer_size()));
+	  }
+	return *this;
+      }
+
+      _Self&
+      operator-=(difference_type __n) _GLIBCXX_NOEXCEPT
+      { return *this += -__n; }
+
+      _GLIBCXX_NODISCARD
+      reference
+      operator[](difference_type __n) const _GLIBCXX_NOEXCEPT
+      { return *(*this + __n); }
+
+      /**
+       *  Prepares to traverse new_node.  Sets everything except
+       *  _M_cur, which should therefore be set by the caller
+       *  immediately afterwards, based on _M_first and _M_last.
+       */
+      void
+      _M_set_node(_Map_pointer __new_node) _GLIBCXX_NOEXCEPT
+      {
+	_M_node = __new_node;
+	_M_first = *__new_node;
+	_M_last = _M_first + difference_type(_S_buffer_size());
+      }
+
+      _GLIBCXX_NODISCARD
+      friend bool
+      operator==(const _Self& __x, const _Self& __y) _GLIBCXX_NOEXCEPT
+      { return __x._M_cur == __y._M_cur; }
+
+      // Note: we also provide overloads whose operands are of the same type in
+      // order to avoid ambiguous overload resolution when std::rel_ops
+      // operators are in scope (for additional details, see libstdc++/3628)
+      template<typename _RefR, typename _PtrR>
+	_GLIBCXX_NODISCARD
+	friend bool
+	operator==(const _Self& __x,
+		   const _Deque_iterator<_Tp, _RefR, _PtrR>& __y)
+	_GLIBCXX_NOEXCEPT
+	{ return __x._M_cur == __y._M_cur; }
+
+#if __cpp_lib_three_way_comparison
+      [[nodiscard]]
+      friend strong_ordering
+      operator<=>(const _Self& __x, const _Self& __y) noexcept
+      {
+	if (const auto __cmp = __x._M_node <=> __y._M_node; __cmp != 0)
+	  return __cmp;
+	return __x._M_cur <=> __y._M_cur;
+      }
+#else
+      _GLIBCXX_NODISCARD
+      friend bool
+      operator!=(const _Self& __x, const _Self& __y) _GLIBCXX_NOEXCEPT
+      { return !(__x == __y); }
+
+      template<typename _RefR, typename _PtrR>
+	_GLIBCXX_NODISCARD
+	friend bool
+	operator!=(const _Self& __x,
+		   const _Deque_iterator<_Tp, _RefR, _PtrR>& __y)
+	_GLIBCXX_NOEXCEPT
+	{ return !(__x == __y); }
+
+      _GLIBCXX_NODISCARD
+      friend bool
+      operator<(const _Self& __x, const _Self& __y) _GLIBCXX_NOEXCEPT
+      {
+	return (__x._M_node == __y._M_node)
+	  ? (__x._M_cur < __y._M_cur) : (__x._M_node < __y._M_node);
+      }
+
+      template<typename _RefR, typename _PtrR>
+	_GLIBCXX_NODISCARD
+	friend bool
+	operator<(const _Self& __x,
+		  const _Deque_iterator<_Tp, _RefR, _PtrR>& __y)
+	_GLIBCXX_NOEXCEPT
+	{
+	  return (__x._M_node == __y._M_node)
+	    ? (__x._M_cur < __y._M_cur) : (__x._M_node < __y._M_node);
+	}
+
+      _GLIBCXX_NODISCARD
+      friend bool
+      operator>(const _Self& __x, const _Self& __y) _GLIBCXX_NOEXCEPT
+      { return __y < __x; }
+
+      template<typename _RefR, typename _PtrR>
+	_GLIBCXX_NODISCARD
+	friend bool
+	operator>(const _Self& __x,
+		  const _Deque_iterator<_Tp, _RefR, _PtrR>& __y)
+	_GLIBCXX_NOEXCEPT
+	{ return __y < __x; }
+
+      _GLIBCXX_NODISCARD
+      friend bool
+      operator<=(const _Self& __x, const _Self& __y) _GLIBCXX_NOEXCEPT
+      { return !(__y < __x); }
+
+      template<typename _RefR, typename _PtrR>
+	_GLIBCXX_NODISCARD
+	friend bool
+	operator<=(const _Self& __x,
+		   const _Deque_iterator<_Tp, _RefR, _PtrR>& __y)
+	_GLIBCXX_NOEXCEPT
+	{ return !(__y < __x); }
+
+      _GLIBCXX_NODISCARD
+      friend bool
+      operator>=(const _Self& __x, const _Self& __y) _GLIBCXX_NOEXCEPT
+      { return !(__x < __y); }
+
+      template<typename _RefR, typename _PtrR>
+	_GLIBCXX_NODISCARD
+	friend bool
+	operator>=(const _Self& __x,
+		   const _Deque_iterator<_Tp, _RefR, _PtrR>& __y)
+	_GLIBCXX_NOEXCEPT
+	{ return !(__x < __y); }
+#endif // three-way comparison
+
+      _GLIBCXX_NODISCARD
+      friend difference_type
+      operator-(const _Self& __x, const _Self& __y) _GLIBCXX_NOEXCEPT
+      {
+	return difference_type(_S_buffer_size())
+	  * (__x._M_node - __y._M_node - bool(__x._M_node))
+	  + (__x._M_cur - __x._M_first)
+	  + (__y._M_last - __y._M_cur);
+      }
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // According to the resolution of DR179 not only the various comparison
+      // operators but also operator- must accept mixed iterator/const_iterator
+      // parameters.
+      template<typename _RefR, typename _PtrR>
+	_GLIBCXX_NODISCARD
+	friend difference_type
+	operator-(const _Self& __x,
+		  const _Deque_iterator<_Tp, _RefR, _PtrR>& __y)
+	_GLIBCXX_NOEXCEPT
+	{
+	  return difference_type(_S_buffer_size())
+	    * (__x._M_node - __y._M_node - bool(__x._M_node))
+	    + (__x._M_cur - __x._M_first)
+	    + (__y._M_last - __y._M_cur);
+	}
+
+      _GLIBCXX_NODISCARD
+      friend _Self
+      operator+(const _Self& __x, difference_type __n) _GLIBCXX_NOEXCEPT
+      {
+	_Self __tmp = __x;
+	__tmp += __n;
+	return __tmp;
+      }
+
+      _GLIBCXX_NODISCARD
+      friend _Self
+      operator-(const _Self& __x, difference_type __n) _GLIBCXX_NOEXCEPT
+      {
+	_Self __tmp = __x;
+	__tmp -= __n;
+	return __tmp;
+      }
+
+      _GLIBCXX_NODISCARD
+      friend _Self
+      operator+(difference_type __n, const _Self& __x) _GLIBCXX_NOEXCEPT
+      { return __x + __n; }
+    };
+
+  /**
+   *  Deque base class.  This class provides the unified face for %deque's
+   *  allocation.  This class's constructor and destructor allocate and
+   *  deallocate (but do not initialize) storage.  This makes %exception
+   *  safety easier.
+   *
+   *  Nothing in this class ever constructs or destroys an actual Tp element.
+   *  (Deque handles that itself.)  Only/All memory management is performed
+   *  here.
+  */
+  template<typename _Tp, typename _Alloc>
+    class _Deque_base
+    {
+    protected:
+      typedef typename __gnu_cxx::__alloc_traits<_Alloc>::template
+	rebind<_Tp>::other _Tp_alloc_type;
+      typedef __gnu_cxx::__alloc_traits<_Tp_alloc_type>	 _Alloc_traits;
+
+#if __cplusplus < 201103L
+      typedef _Tp*					_Ptr;
+      typedef const _Tp*				_Ptr_const;
+#else
+      typedef typename _Alloc_traits::pointer		_Ptr;
+      typedef typename _Alloc_traits::const_pointer	_Ptr_const;
+#endif
+
+      typedef typename _Alloc_traits::template rebind<_Ptr>::other
+	_Map_alloc_type;
+      typedef __gnu_cxx::__alloc_traits<_Map_alloc_type> _Map_alloc_traits;
+
+      typedef _Alloc		  allocator_type;
+
+      allocator_type
+      get_allocator() const _GLIBCXX_NOEXCEPT
+      { return allocator_type(_M_get_Tp_allocator()); }
+
+      typedef _Deque_iterator<_Tp, _Tp&, _Ptr>	  iterator;
+      typedef _Deque_iterator<_Tp, const _Tp&, _Ptr_const>   const_iterator;
+
+      _Deque_base()
+      : _M_impl()
+      { _M_initialize_map(0); }
+
+      _Deque_base(size_t __num_elements)
+      : _M_impl()
+      { _M_initialize_map(__num_elements); }
+
+      _Deque_base(const allocator_type& __a, size_t __num_elements)
+      : _M_impl(__a)
+      { _M_initialize_map(__num_elements); }
+
+      _Deque_base(const allocator_type& __a)
+      : _M_impl(__a)
+      { /* Caller must initialize map. */ }
+
+#if __cplusplus >= 201103L
+      _Deque_base(_Deque_base&& __x)
+      : _M_impl(std::move(__x._M_get_Tp_allocator()))
+      {
+	_M_initialize_map(0);
+	if (__x._M_impl._M_map)
+	  this->_M_impl._M_swap_data(__x._M_impl);
+      }
+
+      _Deque_base(_Deque_base&& __x, const allocator_type& __a)
+      : _M_impl(std::move(__x._M_impl), _Tp_alloc_type(__a))
+      { __x._M_initialize_map(0); }
+
+      _Deque_base(_Deque_base&& __x, const allocator_type& __a, size_t __n)
+      : _M_impl(__a)
+      {
+	if (__x.get_allocator() == __a)
+	  {
+	    if (__x._M_impl._M_map)
+	      {
+		_M_initialize_map(0);
+		this->_M_impl._M_swap_data(__x._M_impl);
+	      }
+	  }
+	else
+	  {
+	    _M_initialize_map(__n);
+	  }
+      }
+#endif
+
+      ~_Deque_base() _GLIBCXX_NOEXCEPT;
+
+      typedef typename iterator::_Map_pointer _Map_pointer;
+
+      struct _Deque_impl_data
+      {
+	_Map_pointer _M_map;
+	size_t _M_map_size;
+	iterator _M_start;
+	iterator _M_finish;
+
+	_Deque_impl_data() _GLIBCXX_NOEXCEPT
+	: _M_map(), _M_map_size(), _M_start(), _M_finish()
+	{ }
+
+#if __cplusplus >= 201103L
+	_Deque_impl_data(const _Deque_impl_data&) = default;
+	_Deque_impl_data&
+	operator=(const _Deque_impl_data&) = default;
+
+	_Deque_impl_data(_Deque_impl_data&& __x) noexcept
+	: _Deque_impl_data(__x)
+	{ __x = _Deque_impl_data(); }
+#endif
+
+	void
+	_M_swap_data(_Deque_impl_data& __x) _GLIBCXX_NOEXCEPT
+	{
+	  // Do not use std::swap(_M_start, __x._M_start), etc as it loses
+	  // information used by TBAA.
+	  std::swap(*this, __x);
+	}
+      };
+
+      // This struct encapsulates the implementation of the std::deque
+      // standard container and at the same time makes use of the EBO
+      // for empty allocators.
+      struct _Deque_impl
+      : public _Tp_alloc_type, public _Deque_impl_data
+      {
+	_Deque_impl() _GLIBCXX_NOEXCEPT_IF(
+	  is_nothrow_default_constructible<_Tp_alloc_type>::value)
+	: _Tp_alloc_type()
+	{ }
+
+	_Deque_impl(const _Tp_alloc_type& __a) _GLIBCXX_NOEXCEPT
+	: _Tp_alloc_type(__a)
+	{ }
+
+#if __cplusplus >= 201103L
+	_Deque_impl(_Deque_impl&&) = default;
+
+	_Deque_impl(_Tp_alloc_type&& __a) noexcept
+	: _Tp_alloc_type(std::move(__a))
+	{ }
+
+	_Deque_impl(_Deque_impl&& __d, _Tp_alloc_type&& __a)
+	: _Tp_alloc_type(std::move(__a)), _Deque_impl_data(std::move(__d))
+	{ }
+#endif
+      };
+
+      _Tp_alloc_type&
+      _M_get_Tp_allocator() _GLIBCXX_NOEXCEPT
+      { return this->_M_impl; }
+
+      const _Tp_alloc_type&
+      _M_get_Tp_allocator() const _GLIBCXX_NOEXCEPT
+      { return this->_M_impl; }
+
+      _Map_alloc_type
+      _M_get_map_allocator() const _GLIBCXX_NOEXCEPT
+      { return _Map_alloc_type(_M_get_Tp_allocator()); }
+
+      _Ptr
+      _M_allocate_node()
+      {
+	typedef __gnu_cxx::__alloc_traits<_Tp_alloc_type> _Traits;
+	return _Traits::allocate(_M_impl, __deque_buf_size(sizeof(_Tp)));
+      }
+
+      void
+      _M_deallocate_node(_Ptr __p) _GLIBCXX_NOEXCEPT
+      {
+	typedef __gnu_cxx::__alloc_traits<_Tp_alloc_type> _Traits;
+	_Traits::deallocate(_M_impl, __p, __deque_buf_size(sizeof(_Tp)));
+      }
+
+      _Map_pointer
+      _M_allocate_map(size_t __n)
+      {
+	_Map_alloc_type __map_alloc = _M_get_map_allocator();
+	return _Map_alloc_traits::allocate(__map_alloc, __n);
+      }
+
+      void
+      _M_deallocate_map(_Map_pointer __p, size_t __n) _GLIBCXX_NOEXCEPT
+      {
+	_Map_alloc_type __map_alloc = _M_get_map_allocator();
+	_Map_alloc_traits::deallocate(__map_alloc, __p, __n);
+      }
+
+      void _M_initialize_map(size_t);
+      void _M_create_nodes(_Map_pointer __nstart, _Map_pointer __nfinish);
+      void _M_destroy_nodes(_Map_pointer __nstart,
+			    _Map_pointer __nfinish) _GLIBCXX_NOEXCEPT;
+      enum { _S_initial_map_size = 8 };
+
+      _Deque_impl _M_impl;
+    };
+
+  template<typename _Tp, typename _Alloc>
+    _Deque_base<_Tp, _Alloc>::
+    ~_Deque_base() _GLIBCXX_NOEXCEPT
+    {
+      if (this->_M_impl._M_map)
+	{
+	  _M_destroy_nodes(this->_M_impl._M_start._M_node,
+			   this->_M_impl._M_finish._M_node + 1);
+	  _M_deallocate_map(this->_M_impl._M_map, this->_M_impl._M_map_size);
+	}
+    }
+
+  /**
+   *  @brief Layout storage.
+   *  @param  __num_elements  The count of T's for which to allocate space
+   *                          at first.
+   *  @return   Nothing.
+   *
+   *  The initial underlying memory layout is a bit complicated...
+  */
+  template<typename _Tp, typename _Alloc>
+    void
+    _Deque_base<_Tp, _Alloc>::
+    _M_initialize_map(size_t __num_elements)
+    {
+      const size_t __num_nodes = (__num_elements / __deque_buf_size(sizeof(_Tp))
+				  + 1);
+
+      this->_M_impl._M_map_size = std::max((size_t) _S_initial_map_size,
+					   size_t(__num_nodes + 2));
+      this->_M_impl._M_map = _M_allocate_map(this->_M_impl._M_map_size);
+
+      // For "small" maps (needing less than _M_map_size nodes), allocation
+      // starts in the middle elements and grows outwards.  So nstart may be
+      // the beginning of _M_map, but for small maps it may be as far in as
+      // _M_map+3.
+
+      _Map_pointer __nstart = (this->_M_impl._M_map
+			       + (this->_M_impl._M_map_size - __num_nodes) / 2);
+      _Map_pointer __nfinish = __nstart + __num_nodes;
+
+      __try
+	{ _M_create_nodes(__nstart, __nfinish); }
+      __catch(...)
+	{
+	  _M_deallocate_map(this->_M_impl._M_map, this->_M_impl._M_map_size);
+	  this->_M_impl._M_map = _Map_pointer();
+	  this->_M_impl._M_map_size = 0;
+	  __throw_exception_again;
+	}
+
+      this->_M_impl._M_start._M_set_node(__nstart);
+      this->_M_impl._M_finish._M_set_node(__nfinish - 1);
+      this->_M_impl._M_start._M_cur = _M_impl._M_start._M_first;
+      this->_M_impl._M_finish._M_cur = (this->_M_impl._M_finish._M_first
+					+ __num_elements
+					% __deque_buf_size(sizeof(_Tp)));
+    }
+
+  template<typename _Tp, typename _Alloc>
+    void
+    _Deque_base<_Tp, _Alloc>::
+    _M_create_nodes(_Map_pointer __nstart, _Map_pointer __nfinish)
+    {
+      _Map_pointer __cur;
+      __try
+	{
+	  for (__cur = __nstart; __cur < __nfinish; ++__cur)
+	    *__cur = this->_M_allocate_node();
+	}
+      __catch(...)
+	{
+	  _M_destroy_nodes(__nstart, __cur);
+	  __throw_exception_again;
+	}
+    }
+
+  template<typename _Tp, typename _Alloc>
+    void
+    _Deque_base<_Tp, _Alloc>::
+    _M_destroy_nodes(_Map_pointer __nstart,
+		     _Map_pointer __nfinish) _GLIBCXX_NOEXCEPT
+    {
+      for (_Map_pointer __n = __nstart; __n < __nfinish; ++__n)
+	_M_deallocate_node(*__n);
+    }
+
+  /**
+   *  @brief  A standard container using fixed-size memory allocation and
+   *  constant-time manipulation of elements at either end.
+   *
+   *  @ingroup sequences
+   *
+   *  @tparam _Tp  Type of element.
+   *  @tparam _Alloc  Allocator type, defaults to allocator<_Tp>.
+   *
+   *  Meets the requirements of a <a href="tables.html#65">container</a>, a
+   *  <a href="tables.html#66">reversible container</a>, and a
+   *  <a href="tables.html#67">sequence</a>, including the
+   *  <a href="tables.html#68">optional sequence requirements</a>.
+   *
+   *  In previous HP/SGI versions of deque, there was an extra template
+   *  parameter so users could control the node size.  This extension turned
+   *  out to violate the C++ standard (it can be detected using template
+   *  template parameters), and it was removed.
+   *
+   *  Here's how a deque<Tp> manages memory.  Each deque has 4 members:
+   *
+   *  - Tp**        _M_map
+   *  - size_t      _M_map_size
+   *  - iterator    _M_start, _M_finish
+   *
+   *  map_size is at least 8.  %map is an array of map_size
+   *  pointers-to-@a nodes.  (The name %map has nothing to do with the
+   *  std::map class, and @b nodes should not be confused with
+   *  std::list's usage of @a node.)
+   *
+   *  A @a node has no specific type name as such, but it is referred
+   *  to as @a node in this file.  It is a simple array-of-Tp.  If Tp
+   *  is very large, there will be one Tp element per node (i.e., an
+   *  @a array of one).  For non-huge Tp's, node size is inversely
+   *  related to Tp size: the larger the Tp, the fewer Tp's will fit
+   *  in a node.  The goal here is to keep the total size of a node
+   *  relatively small and constant over different Tp's, to improve
+   *  allocator efficiency.
+   *
+   *  Not every pointer in the %map array will point to a node.  If
+   *  the initial number of elements in the deque is small, the
+   *  /middle/ %map pointers will be valid, and the ones at the edges
+   *  will be unused.  This same situation will arise as the %map
+   *  grows: available %map pointers, if any, will be on the ends.  As
+   *  new nodes are created, only a subset of the %map's pointers need
+   *  to be copied @a outward.
+   *
+   *  Class invariants:
+   * - For any nonsingular iterator i:
+   *    - i.node points to a member of the %map array.  (Yes, you read that
+   *      correctly:  i.node does not actually point to a node.)  The member of
+   *      the %map array is what actually points to the node.
+   *    - i.first == *(i.node)    (This points to the node (first Tp element).)
+   *    - i.last  == i.first + node_size
+   *    - i.cur is a pointer in the range [i.first, i.last).  NOTE:
+   *      the implication of this is that i.cur is always a dereferenceable
+   *      pointer, even if i is a past-the-end iterator.
+   * - Start and Finish are always nonsingular iterators.  NOTE: this
+   * means that an empty deque must have one node, a deque with <N
+   * elements (where N is the node buffer size) must have one node, a
+   * deque with N through (2N-1) elements must have two nodes, etc.
+   * - For every node other than start.node and finish.node, every
+   * element in the node is an initialized object.  If start.node ==
+   * finish.node, then [start.cur, finish.cur) are initialized
+   * objects, and the elements outside that range are uninitialized
+   * storage.  Otherwise, [start.cur, start.last) and [finish.first,
+   * finish.cur) are initialized objects, and [start.first, start.cur)
+   * and [finish.cur, finish.last) are uninitialized storage.
+   * - [%map, %map + map_size) is a valid, non-empty range.
+   * - [start.node, finish.node] is a valid range contained within
+   *   [%map, %map + map_size).
+   * - A pointer in the range [%map, %map + map_size) points to an allocated
+   *   node if and only if the pointer is in the range
+   *   [start.node, finish.node].
+   *
+   *  Here's the magic:  nothing in deque is @b aware of the discontiguous
+   *  storage!
+   *
+   *  The memory setup and layout occurs in the parent, _Base, and the iterator
+   *  class is entirely responsible for @a leaping from one node to the next.
+   *  All the implementation routines for deque itself work only through the
+   *  start and finish iterators.  This keeps the routines simple and sane,
+   *  and we can use other standard algorithms as well.
+  */
+  template<typename _Tp, typename _Alloc = std::allocator<_Tp> >
+    class deque : protected _Deque_base<_Tp, _Alloc>
+    {
+#ifdef _GLIBCXX_CONCEPT_CHECKS
+      // concept requirements
+      typedef typename _Alloc::value_type	_Alloc_value_type;
+# if __cplusplus < 201103L
+      __glibcxx_class_requires(_Tp, _SGIAssignableConcept)
+# endif
+      __glibcxx_class_requires2(_Tp, _Alloc_value_type, _SameTypeConcept)
+#endif
+
+#if __cplusplus >= 201103L
+      static_assert(is_same<typename remove_cv<_Tp>::type, _Tp>::value,
+	  "std::deque must have a non-const, non-volatile value_type");
+# if __cplusplus > 201703L || defined __STRICT_ANSI__
+      static_assert(is_same<typename _Alloc::value_type, _Tp>::value,
+	  "std::deque must have the same value_type as its allocator");
+# endif
+#endif
+
+      typedef _Deque_base<_Tp, _Alloc>			_Base;
+      typedef typename _Base::_Tp_alloc_type		_Tp_alloc_type;
+      typedef typename _Base::_Alloc_traits		_Alloc_traits;
+      typedef typename _Base::_Map_pointer		_Map_pointer;
+
+    public:
+      typedef _Tp					value_type;
+      typedef typename _Alloc_traits::pointer		pointer;
+      typedef typename _Alloc_traits::const_pointer	const_pointer;
+      typedef typename _Alloc_traits::reference		reference;
+      typedef typename _Alloc_traits::const_reference	const_reference;
+      typedef typename _Base::iterator			iterator;
+      typedef typename _Base::const_iterator		const_iterator;
+      typedef std::reverse_iterator<const_iterator>	const_reverse_iterator;
+      typedef std::reverse_iterator<iterator>		reverse_iterator;
+      typedef size_t					size_type;
+      typedef ptrdiff_t					difference_type;
+      typedef _Alloc					allocator_type;
+
+    private:
+      static size_t _S_buffer_size() _GLIBCXX_NOEXCEPT
+      { return __deque_buf_size(sizeof(_Tp)); }
+
+      // Functions controlling memory layout, and nothing else.
+      using _Base::_M_initialize_map;
+      using _Base::_M_create_nodes;
+      using _Base::_M_destroy_nodes;
+      using _Base::_M_allocate_node;
+      using _Base::_M_deallocate_node;
+      using _Base::_M_allocate_map;
+      using _Base::_M_deallocate_map;
+      using _Base::_M_get_Tp_allocator;
+
+      /**
+       *  A total of four data members accumulated down the hierarchy.
+       *  May be accessed via _M_impl.*
+       */
+      using _Base::_M_impl;
+
+    public:
+      // [23.2.1.1] construct/copy/destroy
+      // (assign() and get_allocator() are also listed in this section)
+
+      /**
+       *  @brief  Creates a %deque with no elements.
+       */
+#if __cplusplus >= 201103L
+      deque() = default;
+#else
+      deque() { }
+#endif
+
+      /**
+       *  @brief  Creates a %deque with no elements.
+       *  @param  __a  An allocator object.
+       */
+      explicit
+      deque(const allocator_type& __a)
+      : _Base(__a, 0) { }
+
+#if __cplusplus >= 201103L
+      /**
+       *  @brief  Creates a %deque with default constructed elements.
+       *  @param  __n  The number of elements to initially create.
+       *  @param  __a  An allocator.
+       *
+       *  This constructor fills the %deque with @a n default
+       *  constructed elements.
+       */
+      explicit
+      deque(size_type __n, const allocator_type& __a = allocator_type())
+      : _Base(__a, _S_check_init_len(__n, __a))
+      { _M_default_initialize(); }
+
+      /**
+       *  @brief  Creates a %deque with copies of an exemplar element.
+       *  @param  __n  The number of elements to initially create.
+       *  @param  __value  An element to copy.
+       *  @param  __a  An allocator.
+       *
+       *  This constructor fills the %deque with @a __n copies of @a __value.
+       */
+      deque(size_type __n, const value_type& __value,
+	    const allocator_type& __a = allocator_type())
+      : _Base(__a, _S_check_init_len(__n, __a))
+      { _M_fill_initialize(__value); }
+#else
+      /**
+       *  @brief  Creates a %deque with copies of an exemplar element.
+       *  @param  __n  The number of elements to initially create.
+       *  @param  __value  An element to copy.
+       *  @param  __a  An allocator.
+       *
+       *  This constructor fills the %deque with @a __n copies of @a __value.
+       */
+      explicit
+      deque(size_type __n, const value_type& __value = value_type(),
+	    const allocator_type& __a = allocator_type())
+      : _Base(__a, _S_check_init_len(__n, __a))
+      { _M_fill_initialize(__value); }
+#endif
+
+      /**
+       *  @brief  %Deque copy constructor.
+       *  @param  __x  A %deque of identical element and allocator types.
+       *
+       *  The newly-created %deque uses a copy of the allocator object used
+       *  by @a __x (unless the allocator traits dictate a different object).
+       */
+      deque(const deque& __x)
+      : _Base(_Alloc_traits::_S_select_on_copy(__x._M_get_Tp_allocator()),
+	      __x.size())
+      { std::__uninitialized_copy_a(__x.begin(), __x.end(),
+				    this->_M_impl._M_start,
+				    _M_get_Tp_allocator()); }
+
+#if __cplusplus >= 201103L
+      /**
+       *  @brief  %Deque move constructor.
+       *
+       *  The newly-created %deque contains the exact contents of the
+       *  moved instance.
+       *  The contents of the moved instance are a valid, but unspecified
+       *  %deque.
+       */
+      deque(deque&&) = default;
+
+      /// Copy constructor with alternative allocator
+      deque(const deque& __x, const __type_identity_t<allocator_type>& __a)
+      : _Base(__a, __x.size())
+      { std::__uninitialized_copy_a(__x.begin(), __x.end(),
+				    this->_M_impl._M_start,
+				    _M_get_Tp_allocator()); }
+
+      /// Move constructor with alternative allocator
+      deque(deque&& __x, const __type_identity_t<allocator_type>& __a)
+      : deque(std::move(__x), __a, typename _Alloc_traits::is_always_equal{})
+      { }
+
+    private:
+      deque(deque&& __x, const allocator_type& __a, true_type)
+      : _Base(std::move(__x), __a)
+      { }
+
+      deque(deque&& __x, const allocator_type& __a, false_type)
+      : _Base(std::move(__x), __a, __x.size())
+      {
+	if (__x.get_allocator() != __a && !__x.empty())
+	  {
+	    std::__uninitialized_move_a(__x.begin(), __x.end(),
+					this->_M_impl._M_start,
+					_M_get_Tp_allocator());
+	    __x.clear();
+	  }
+      }
+
+    public:
+      /**
+       *  @brief  Builds a %deque from an initializer list.
+       *  @param  __l  An initializer_list.
+       *  @param  __a  An allocator object.
+       *
+       *  Create a %deque consisting of copies of the elements in the
+       *  initializer_list @a __l.
+       *
+       *  This will call the element type's copy constructor N times
+       *  (where N is __l.size()) and do no memory reallocation.
+       */
+      deque(initializer_list<value_type> __l,
+	    const allocator_type& __a = allocator_type())
+      : _Base(__a)
+      {
+	_M_range_initialize(__l.begin(), __l.end(),
+			    random_access_iterator_tag());
+      }
+#endif
+
+      /**
+       *  @brief  Builds a %deque from a range.
+       *  @param  __first  An input iterator.
+       *  @param  __last  An input iterator.
+       *  @param  __a  An allocator object.
+       *
+       *  Create a %deque consisting of copies of the elements from [__first,
+       *  __last).
+       *
+       *  If the iterators are forward, bidirectional, or random-access, then
+       *  this will call the elements' copy constructor N times (where N is
+       *  distance(__first,__last)) and do no memory reallocation.  But if only
+       *  input iterators are used, then this will do at most 2N calls to the
+       *  copy constructor, and logN memory reallocations.
+       */
+#if __cplusplus >= 201103L
+      template<typename _InputIterator,
+	       typename = std::_RequireInputIter<_InputIterator>>
+	deque(_InputIterator __first, _InputIterator __last,
+	      const allocator_type& __a = allocator_type())
+	: _Base(__a)
+	{
+	  _M_range_initialize(__first, __last,
+			      std::__iterator_category(__first));
+	}
+#else
+      template<typename _InputIterator>
+	deque(_InputIterator __first, _InputIterator __last,
+	      const allocator_type& __a = allocator_type())
+	: _Base(__a)
+	{
+	  // Check whether it's an integral type.  If so, it's not an iterator.
+	  typedef typename std::__is_integer<_InputIterator>::__type _Integral;
+	  _M_initialize_dispatch(__first, __last, _Integral());
+	}
+#endif
+
+      /**
+       *  The dtor only erases the elements, and note that if the elements
+       *  themselves are pointers, the pointed-to memory is not touched in any
+       *  way.  Managing the pointer is the user's responsibility.
+       */
+      ~deque()
+      { _M_destroy_data(begin(), end(), _M_get_Tp_allocator()); }
+
+      /**
+       *  @brief  %Deque assignment operator.
+       *  @param  __x  A %deque of identical element and allocator types.
+       *
+       *  All the elements of @a x are copied.
+       *
+       *  The newly-created %deque uses a copy of the allocator object used
+       *  by @a __x (unless the allocator traits dictate a different object).
+       */
+      deque&
+      operator=(const deque& __x);
+
+#if __cplusplus >= 201103L
+      /**
+       *  @brief  %Deque move assignment operator.
+       *  @param  __x  A %deque of identical element and allocator types.
+       *
+       *  The contents of @a __x are moved into this deque (without copying,
+       *  if the allocators permit it).
+       *  @a __x is a valid, but unspecified %deque.
+       */
+      deque&
+      operator=(deque&& __x) noexcept(_Alloc_traits::_S_always_equal())
+      {
+	using __always_equal = typename _Alloc_traits::is_always_equal;
+	_M_move_assign1(std::move(__x), __always_equal{});
+	return *this;
+      }
+
+      /**
+       *  @brief  Assigns an initializer list to a %deque.
+       *  @param  __l  An initializer_list.
+       *
+       *  This function fills a %deque with copies of the elements in the
+       *  initializer_list @a __l.
+       *
+       *  Note that the assignment completely changes the %deque and that the
+       *  resulting %deque's size is the same as the number of elements
+       *  assigned.
+       */
+      deque&
+      operator=(initializer_list<value_type> __l)
+      {
+	_M_assign_aux(__l.begin(), __l.end(),
+		      random_access_iterator_tag());
+	return *this;
+      }
+#endif
+
+      /**
+       *  @brief  Assigns a given value to a %deque.
+       *  @param  __n  Number of elements to be assigned.
+       *  @param  __val  Value to be assigned.
+       *
+       *  This function fills a %deque with @a n copies of the given
+       *  value.  Note that the assignment completely changes the
+       *  %deque and that the resulting %deque's size is the same as
+       *  the number of elements assigned.
+       */
+      void
+      assign(size_type __n, const value_type& __val)
+      { _M_fill_assign(__n, __val); }
+
+      /**
+       *  @brief  Assigns a range to a %deque.
+       *  @param  __first  An input iterator.
+       *  @param  __last   An input iterator.
+       *
+       *  This function fills a %deque with copies of the elements in the
+       *  range [__first,__last).
+       *
+       *  Note that the assignment completely changes the %deque and that the
+       *  resulting %deque's size is the same as the number of elements
+       *  assigned.
+       */
+#if __cplusplus >= 201103L
+      template<typename _InputIterator,
+	       typename = std::_RequireInputIter<_InputIterator>>
+	void
+	assign(_InputIterator __first, _InputIterator __last)
+	{ _M_assign_aux(__first, __last, std::__iterator_category(__first)); }
+#else
+      template<typename _InputIterator>
+	void
+	assign(_InputIterator __first, _InputIterator __last)
+	{
+	  typedef typename std::__is_integer<_InputIterator>::__type _Integral;
+	  _M_assign_dispatch(__first, __last, _Integral());
+	}
+#endif
+
+#if __cplusplus >= 201103L
+      /**
+       *  @brief  Assigns an initializer list to a %deque.
+       *  @param  __l  An initializer_list.
+       *
+       *  This function fills a %deque with copies of the elements in the
+       *  initializer_list @a __l.
+       *
+       *  Note that the assignment completely changes the %deque and that the
+       *  resulting %deque's size is the same as the number of elements
+       *  assigned.
+       */
+      void
+      assign(initializer_list<value_type> __l)
+      { _M_assign_aux(__l.begin(), __l.end(), random_access_iterator_tag()); }
+#endif
+
+      /// Get a copy of the memory allocation object.
+      _GLIBCXX_NODISCARD
+      allocator_type
+      get_allocator() const _GLIBCXX_NOEXCEPT
+      { return _Base::get_allocator(); }
+
+      // iterators
+      /**
+       *  Returns a read/write iterator that points to the first element in the
+       *  %deque.  Iteration is done in ordinary element order.
+       */
+      _GLIBCXX_NODISCARD
+      iterator
+      begin() _GLIBCXX_NOEXCEPT
+      { return this->_M_impl._M_start; }
+
+      /**
+       *  Returns a read-only (constant) iterator that points to the first
+       *  element in the %deque.  Iteration is done in ordinary element order.
+       */
+      _GLIBCXX_NODISCARD
+      const_iterator
+      begin() const _GLIBCXX_NOEXCEPT
+      { return this->_M_impl._M_start; }
+
+      /**
+       *  Returns a read/write iterator that points one past the last
+       *  element in the %deque.  Iteration is done in ordinary
+       *  element order.
+       */
+      _GLIBCXX_NODISCARD
+      iterator
+      end() _GLIBCXX_NOEXCEPT
+      { return this->_M_impl._M_finish; }
+
+      /**
+       *  Returns a read-only (constant) iterator that points one past
+       *  the last element in the %deque.  Iteration is done in
+       *  ordinary element order.
+       */
+      _GLIBCXX_NODISCARD
+      const_iterator
+      end() const _GLIBCXX_NOEXCEPT
+      { return this->_M_impl._M_finish; }
+
+      /**
+       *  Returns a read/write reverse iterator that points to the
+       *  last element in the %deque.  Iteration is done in reverse
+       *  element order.
+       */
+      _GLIBCXX_NODISCARD
+      reverse_iterator
+      rbegin() _GLIBCXX_NOEXCEPT
+      { return reverse_iterator(this->_M_impl._M_finish); }
+
+      /**
+       *  Returns a read-only (constant) reverse iterator that points
+       *  to the last element in the %deque.  Iteration is done in
+       *  reverse element order.
+       */
+      _GLIBCXX_NODISCARD
+      const_reverse_iterator
+      rbegin() const _GLIBCXX_NOEXCEPT
+      { return const_reverse_iterator(this->_M_impl._M_finish); }
+
+      /**
+       *  Returns a read/write reverse iterator that points to one
+       *  before the first element in the %deque.  Iteration is done
+       *  in reverse element order.
+       */
+      _GLIBCXX_NODISCARD
+      reverse_iterator
+      rend() _GLIBCXX_NOEXCEPT
+      { return reverse_iterator(this->_M_impl._M_start); }
+
+      /**
+       *  Returns a read-only (constant) reverse iterator that points
+       *  to one before the first element in the %deque.  Iteration is
+       *  done in reverse element order.
+       */
+      _GLIBCXX_NODISCARD
+      const_reverse_iterator
+      rend() const _GLIBCXX_NOEXCEPT
+      { return const_reverse_iterator(this->_M_impl._M_start); }
+
+#if __cplusplus >= 201103L
+      /**
+       *  Returns a read-only (constant) iterator that points to the first
+       *  element in the %deque.  Iteration is done in ordinary element order.
+       */
+      [[__nodiscard__]]
+      const_iterator
+      cbegin() const noexcept
+      { return this->_M_impl._M_start; }
+
+      /**
+       *  Returns a read-only (constant) iterator that points one past
+       *  the last element in the %deque.  Iteration is done in
+       *  ordinary element order.
+       */
+      [[__nodiscard__]]
+      const_iterator
+      cend() const noexcept
+      { return this->_M_impl._M_finish; }
+
+      /**
+       *  Returns a read-only (constant) reverse iterator that points
+       *  to the last element in the %deque.  Iteration is done in
+       *  reverse element order.
+       */
+      [[__nodiscard__]]
+      const_reverse_iterator
+      crbegin() const noexcept
+      { return const_reverse_iterator(this->_M_impl._M_finish); }
+
+      /**
+       *  Returns a read-only (constant) reverse iterator that points
+       *  to one before the first element in the %deque.  Iteration is
+       *  done in reverse element order.
+       */
+      [[__nodiscard__]]
+      const_reverse_iterator
+      crend() const noexcept
+      { return const_reverse_iterator(this->_M_impl._M_start); }
+#endif
+
+      // [23.2.1.2] capacity
+      /**  Returns the number of elements in the %deque.  */
+      _GLIBCXX_NODISCARD
+      size_type
+      size() const _GLIBCXX_NOEXCEPT
+      { return this->_M_impl._M_finish - this->_M_impl._M_start; }
+
+      /**  Returns the size() of the largest possible %deque.  */
+      _GLIBCXX_NODISCARD
+      size_type
+      max_size() const _GLIBCXX_NOEXCEPT
+      { return _S_max_size(_M_get_Tp_allocator()); }
+
+#if __cplusplus >= 201103L
+      /**
+       *  @brief  Resizes the %deque to the specified number of elements.
+       *  @param  __new_size  Number of elements the %deque should contain.
+       *
+       *  This function will %resize the %deque to the specified
+       *  number of elements.  If the number is smaller than the
+       *  %deque's current size the %deque is truncated, otherwise
+       *  default constructed elements are appended.
+       */
+      void
+      resize(size_type __new_size)
+      {
+	const size_type __len = size();
+	if (__new_size > __len)
+	  _M_default_append(__new_size - __len);
+	else if (__new_size < __len)
+	  _M_erase_at_end(this->_M_impl._M_start
+			  + difference_type(__new_size));
+      }
+
+      /**
+       *  @brief  Resizes the %deque to the specified number of elements.
+       *  @param  __new_size  Number of elements the %deque should contain.
+       *  @param  __x  Data with which new elements should be populated.
+       *
+       *  This function will %resize the %deque to the specified
+       *  number of elements.  If the number is smaller than the
+       *  %deque's current size the %deque is truncated, otherwise the
+       *  %deque is extended and new elements are populated with given
+       *  data.
+       */
+      void
+      resize(size_type __new_size, const value_type& __x)
+#else
+      /**
+       *  @brief  Resizes the %deque to the specified number of elements.
+       *  @param  __new_size  Number of elements the %deque should contain.
+       *  @param  __x  Data with which new elements should be populated.
+       *
+       *  This function will %resize the %deque to the specified
+       *  number of elements.  If the number is smaller than the
+       *  %deque's current size the %deque is truncated, otherwise the
+       *  %deque is extended and new elements are populated with given
+       *  data.
+       */
+      void
+      resize(size_type __new_size, value_type __x = value_type())
+#endif
+      {
+	const size_type __len = size();
+	if (__new_size > __len)
+	  _M_fill_insert(this->_M_impl._M_finish, __new_size - __len, __x);
+	else if (__new_size < __len)
+	  _M_erase_at_end(this->_M_impl._M_start
+			  + difference_type(__new_size));
+      }
+
+#if __cplusplus >= 201103L
+      /**  A non-binding request to reduce memory use.  */
+      void
+      shrink_to_fit() noexcept
+      { _M_shrink_to_fit(); }
+#endif
+
+      /**
+       *  Returns true if the %deque is empty.  (Thus begin() would
+       *  equal end().)
+       */
+      _GLIBCXX_NODISCARD bool
+      empty() const _GLIBCXX_NOEXCEPT
+      { return this->_M_impl._M_finish == this->_M_impl._M_start; }
+
+      // element access
+      /**
+       *  @brief Subscript access to the data contained in the %deque.
+       *  @param __n The index of the element for which data should be
+       *  accessed.
+       *  @return  Read/write reference to data.
+       *
+       *  This operator allows for easy, array-style, data access.
+       *  Note that data access with this operator is unchecked and
+       *  out_of_range lookups are not defined. (For checked lookups
+       *  see at().)
+       */
+      _GLIBCXX_NODISCARD
+      reference
+      operator[](size_type __n) _GLIBCXX_NOEXCEPT
+      {
+	__glibcxx_requires_subscript(__n);
+	return this->_M_impl._M_start[difference_type(__n)];
+      }
+
+      /**
+       *  @brief Subscript access to the data contained in the %deque.
+       *  @param __n The index of the element for which data should be
+       *  accessed.
+       *  @return  Read-only (constant) reference to data.
+       *
+       *  This operator allows for easy, array-style, data access.
+       *  Note that data access with this operator is unchecked and
+       *  out_of_range lookups are not defined. (For checked lookups
+       *  see at().)
+       */
+      _GLIBCXX_NODISCARD
+      const_reference
+      operator[](size_type __n) const _GLIBCXX_NOEXCEPT
+      {
+	__glibcxx_requires_subscript(__n);
+	return this->_M_impl._M_start[difference_type(__n)];
+      }
+
+    protected:
+      /// Safety check used only from at().
+      void
+      _M_range_check(size_type __n) const
+      {
+	if (__n >= this->size())
+	  __throw_out_of_range_fmt(__N("deque::_M_range_check: __n "
+				       "(which is %zu)>= this->size() "
+				       "(which is %zu)"),
+				   __n, this->size());
+      }
+
+    public:
+      /**
+       *  @brief  Provides access to the data contained in the %deque.
+       *  @param __n The index of the element for which data should be
+       *  accessed.
+       *  @return  Read/write reference to data.
+       *  @throw  std::out_of_range  If @a __n is an invalid index.
+       *
+       *  This function provides for safer data access.  The parameter
+       *  is first checked that it is in the range of the deque.  The
+       *  function throws out_of_range if the check fails.
+       */
+      reference
+      at(size_type __n)
+      {
+	_M_range_check(__n);
+	return (*this)[__n];
+      }
+
+      /**
+       *  @brief  Provides access to the data contained in the %deque.
+       *  @param __n The index of the element for which data should be
+       *  accessed.
+       *  @return  Read-only (constant) reference to data.
+       *  @throw  std::out_of_range  If @a __n is an invalid index.
+       *
+       *  This function provides for safer data access.  The parameter is first
+       *  checked that it is in the range of the deque.  The function throws
+       *  out_of_range if the check fails.
+       */
+      const_reference
+      at(size_type __n) const
+      {
+	_M_range_check(__n);
+	return (*this)[__n];
+      }
+
+      /**
+       *  Returns a read/write reference to the data at the first
+       *  element of the %deque.
+       */
+      _GLIBCXX_NODISCARD
+      reference
+      front() _GLIBCXX_NOEXCEPT
+      {
+	__glibcxx_requires_nonempty();
+	return *begin();
+      }
+
+      /**
+       *  Returns a read-only (constant) reference to the data at the first
+       *  element of the %deque.
+       */
+      _GLIBCXX_NODISCARD
+      const_reference
+      front() const _GLIBCXX_NOEXCEPT
+      {
+	__glibcxx_requires_nonempty();
+	return *begin();
+      }
+
+      /**
+       *  Returns a read/write reference to the data at the last element of the
+       *  %deque.
+       */
+      _GLIBCXX_NODISCARD
+      reference
+      back() _GLIBCXX_NOEXCEPT
+      {
+	__glibcxx_requires_nonempty();
+	iterator __tmp = end();
+	--__tmp;
+	return *__tmp;
+      }
+
+      /**
+       *  Returns a read-only (constant) reference to the data at the last
+       *  element of the %deque.
+       */
+      _GLIBCXX_NODISCARD
+      const_reference
+      back() const _GLIBCXX_NOEXCEPT
+      {
+	__glibcxx_requires_nonempty();
+	const_iterator __tmp = end();
+	--__tmp;
+	return *__tmp;
+      }
+
+      // [23.2.1.2] modifiers
+      /**
+       *  @brief  Add data to the front of the %deque.
+       *  @param  __x  Data to be added.
+       *
+       *  This is a typical stack operation.  The function creates an
+       *  element at the front of the %deque and assigns the given
+       *  data to it.  Due to the nature of a %deque this operation
+       *  can be done in constant time.
+       */
+      void
+      push_front(const value_type& __x)
+      {
+	if (this->_M_impl._M_start._M_cur != this->_M_impl._M_start._M_first)
+	  {
+	    _Alloc_traits::construct(this->_M_impl,
+				     this->_M_impl._M_start._M_cur - 1,
+				     __x);
+	    --this->_M_impl._M_start._M_cur;
+	  }
+	else
+	  _M_push_front_aux(__x);
+      }
+
+#if __cplusplus >= 201103L
+      void
+      push_front(value_type&& __x)
+      { emplace_front(std::move(__x)); }
+
+      template<typename... _Args>
+#if __cplusplus > 201402L
+	reference
+#else
+	void
+#endif
+	emplace_front(_Args&&... __args);
+#endif
+
+      /**
+       *  @brief  Add data to the end of the %deque.
+       *  @param  __x  Data to be added.
+       *
+       *  This is a typical stack operation.  The function creates an
+       *  element at the end of the %deque and assigns the given data
+       *  to it.  Due to the nature of a %deque this operation can be
+       *  done in constant time.
+       */
+      void
+      push_back(const value_type& __x)
+      {
+	if (this->_M_impl._M_finish._M_cur
+	    != this->_M_impl._M_finish._M_last - 1)
+	  {
+	    _Alloc_traits::construct(this->_M_impl,
+				     this->_M_impl._M_finish._M_cur, __x);
+	    ++this->_M_impl._M_finish._M_cur;
+	  }
+	else
+	  _M_push_back_aux(__x);
+      }
+
+#if __cplusplus >= 201103L
+      void
+      push_back(value_type&& __x)
+      { emplace_back(std::move(__x)); }
+
+      template<typename... _Args>
+#if __cplusplus > 201402L
+	reference
+#else
+	void
+#endif
+	emplace_back(_Args&&... __args);
+#endif
+
+      /**
+       *  @brief  Removes first element.
+       *
+       *  This is a typical stack operation.  It shrinks the %deque by one.
+       *
+       *  Note that no data is returned, and if the first element's data is
+       *  needed, it should be retrieved before pop_front() is called.
+       */
+      void
+      pop_front() _GLIBCXX_NOEXCEPT
+      {
+	__glibcxx_requires_nonempty();
+	if (this->_M_impl._M_start._M_cur
+	    != this->_M_impl._M_start._M_last - 1)
+	  {
+	    _Alloc_traits::destroy(_M_get_Tp_allocator(),
+				   this->_M_impl._M_start._M_cur);
+	    ++this->_M_impl._M_start._M_cur;
+	  }
+	else
+	  _M_pop_front_aux();
+      }
+
+      /**
+       *  @brief  Removes last element.
+       *
+       *  This is a typical stack operation.  It shrinks the %deque by one.
+       *
+       *  Note that no data is returned, and if the last element's data is
+       *  needed, it should be retrieved before pop_back() is called.
+       */
+      void
+      pop_back() _GLIBCXX_NOEXCEPT
+      {
+	__glibcxx_requires_nonempty();
+	if (this->_M_impl._M_finish._M_cur
+	    != this->_M_impl._M_finish._M_first)
+	  {
+	    --this->_M_impl._M_finish._M_cur;
+	    _Alloc_traits::destroy(_M_get_Tp_allocator(),
+				   this->_M_impl._M_finish._M_cur);
+	  }
+	else
+	  _M_pop_back_aux();
+      }
+
+#if __cplusplus >= 201103L
+      /**
+       *  @brief  Inserts an object in %deque before specified iterator.
+       *  @param  __position  A const_iterator into the %deque.
+       *  @param  __args  Arguments.
+       *  @return  An iterator that points to the inserted data.
+       *
+       *  This function will insert an object of type T constructed
+       *  with T(std::forward<Args>(args)...) before the specified location.
+       */
+      template<typename... _Args>
+	iterator
+	emplace(const_iterator __position, _Args&&... __args);
+
+      /**
+       *  @brief  Inserts given value into %deque before specified iterator.
+       *  @param  __position  A const_iterator into the %deque.
+       *  @param  __x  Data to be inserted.
+       *  @return  An iterator that points to the inserted data.
+       *
+       *  This function will insert a copy of the given value before the
+       *  specified location.
+       */
+      iterator
+      insert(const_iterator __position, const value_type& __x);
+#else
+      /**
+       *  @brief  Inserts given value into %deque before specified iterator.
+       *  @param  __position  An iterator into the %deque.
+       *  @param  __x  Data to be inserted.
+       *  @return  An iterator that points to the inserted data.
+       *
+       *  This function will insert a copy of the given value before the
+       *  specified location.
+       */
+      iterator
+      insert(iterator __position, const value_type& __x);
+#endif
+
+#if __cplusplus >= 201103L
+      /**
+       *  @brief  Inserts given rvalue into %deque before specified iterator.
+       *  @param  __position  A const_iterator into the %deque.
+       *  @param  __x  Data to be inserted.
+       *  @return  An iterator that points to the inserted data.
+       *
+       *  This function will insert a copy of the given rvalue before the
+       *  specified location.
+       */
+      iterator
+      insert(const_iterator __position, value_type&& __x)
+      { return emplace(__position, std::move(__x)); }
+
+      /**
+       *  @brief  Inserts an initializer list into the %deque.
+       *  @param  __p  An iterator into the %deque.
+       *  @param  __l  An initializer_list.
+       *  @return  An iterator that points to the inserted data.
+       *
+       *  This function will insert copies of the data in the
+       *  initializer_list @a __l into the %deque before the location
+       *  specified by @a __p.  This is known as <em>list insert</em>.
+       */
+      iterator
+      insert(const_iterator __p, initializer_list<value_type> __l)
+      {
+	auto __offset = __p - cbegin();
+	_M_range_insert_aux(__p._M_const_cast(), __l.begin(), __l.end(),
+			    std::random_access_iterator_tag());
+	return begin() + __offset;
+      }
+
+      /**
+       *  @brief  Inserts a number of copies of given data into the %deque.
+       *  @param  __position  A const_iterator into the %deque.
+       *  @param  __n  Number of elements to be inserted.
+       *  @param  __x  Data to be inserted.
+       *  @return  An iterator that points to the inserted data.
+       *
+       *  This function will insert a specified number of copies of the given
+       *  data before the location specified by @a __position.
+       */
+      iterator
+      insert(const_iterator __position, size_type __n, const value_type& __x)
+      {
+	difference_type __offset = __position - cbegin();
+	_M_fill_insert(__position._M_const_cast(), __n, __x);
+	return begin() + __offset;
+      }
+#else
+      /**
+       *  @brief  Inserts a number of copies of given data into the %deque.
+       *  @param  __position  An iterator into the %deque.
+       *  @param  __n  Number of elements to be inserted.
+       *  @param  __x  Data to be inserted.
+       *
+       *  This function will insert a specified number of copies of the given
+       *  data before the location specified by @a __position.
+       */
+      void
+      insert(iterator __position, size_type __n, const value_type& __x)
+      { _M_fill_insert(__position, __n, __x); }
+#endif
+
+#if __cplusplus >= 201103L
+      /**
+       *  @brief  Inserts a range into the %deque.
+       *  @param  __position  A const_iterator into the %deque.
+       *  @param  __first  An input iterator.
+       *  @param  __last   An input iterator.
+       *  @return  An iterator that points to the inserted data.
+       *
+       *  This function will insert copies of the data in the range
+       *  [__first,__last) into the %deque before the location specified
+       *  by @a __position.  This is known as <em>range insert</em>.
+       */
+      template<typename _InputIterator,
+	       typename = std::_RequireInputIter<_InputIterator>>
+	iterator
+	insert(const_iterator __position, _InputIterator __first,
+	       _InputIterator __last)
+	{
+	  difference_type __offset = __position - cbegin();
+	  _M_range_insert_aux(__position._M_const_cast(), __first, __last,
+			      std::__iterator_category(__first));
+	  return begin() + __offset;
+	}
+#else
+      /**
+       *  @brief  Inserts a range into the %deque.
+       *  @param  __position  An iterator into the %deque.
+       *  @param  __first  An input iterator.
+       *  @param  __last   An input iterator.
+       *
+       *  This function will insert copies of the data in the range
+       *  [__first,__last) into the %deque before the location specified
+       *  by @a __position.  This is known as <em>range insert</em>.
+       */
+      template<typename _InputIterator>
+	void
+	insert(iterator __position, _InputIterator __first,
+	       _InputIterator __last)
+	{
+	  // Check whether it's an integral type.  If so, it's not an iterator.
+	  typedef typename std::__is_integer<_InputIterator>::__type _Integral;
+	  _M_insert_dispatch(__position, __first, __last, _Integral());
+	}
+#endif
+
+      /**
+       *  @brief  Remove element at given position.
+       *  @param  __position  Iterator pointing to element to be erased.
+       *  @return  An iterator pointing to the next element (or end()).
+       *
+       *  This function will erase the element at the given position and thus
+       *  shorten the %deque by one.
+       *
+       *  The user is cautioned that
+       *  this function only erases the element, and that if the element is
+       *  itself a pointer, the pointed-to memory is not touched in any way.
+       *  Managing the pointer is the user's responsibility.
+       */
+      iterator
+#if __cplusplus >= 201103L
+      erase(const_iterator __position)
+#else
+      erase(iterator __position)
+#endif
+      { return _M_erase(__position._M_const_cast()); }
+
+      /**
+       *  @brief  Remove a range of elements.
+       *  @param  __first  Iterator pointing to the first element to be erased.
+       *  @param  __last  Iterator pointing to one past the last element to be
+       *                erased.
+       *  @return  An iterator pointing to the element pointed to by @a last
+       *           prior to erasing (or end()).
+       *
+       *  This function will erase the elements in the range
+       *  [__first,__last) and shorten the %deque accordingly.
+       *
+       *  The user is cautioned that
+       *  this function only erases the elements, and that if the elements
+       *  themselves are pointers, the pointed-to memory is not touched in any
+       *  way.  Managing the pointer is the user's responsibility.
+       */
+      iterator
+#if __cplusplus >= 201103L
+      erase(const_iterator __first, const_iterator __last)
+#else
+      erase(iterator __first, iterator __last)
+#endif
+      { return _M_erase(__first._M_const_cast(), __last._M_const_cast()); }
+
+      /**
+       *  @brief  Swaps data with another %deque.
+       *  @param  __x  A %deque of the same element and allocator types.
+       *
+       *  This exchanges the elements between two deques in constant time.
+       *  (Four pointers, so it should be quite fast.)
+       *  Note that the global std::swap() function is specialized such that
+       *  std::swap(d1,d2) will feed to this function.
+       *
+       *  Whether the allocators are swapped depends on the allocator traits.
+       */
+      void
+      swap(deque& __x) _GLIBCXX_NOEXCEPT
+      {
+#if __cplusplus >= 201103L
+	__glibcxx_assert(_Alloc_traits::propagate_on_container_swap::value
+			 || _M_get_Tp_allocator() == __x._M_get_Tp_allocator());
+#endif
+	_M_impl._M_swap_data(__x._M_impl);
+	_Alloc_traits::_S_on_swap(_M_get_Tp_allocator(),
+				  __x._M_get_Tp_allocator());
+      }
+
+      /**
+       *  Erases all the elements.  Note that this function only erases the
+       *  elements, and that if the elements themselves are pointers, the
+       *  pointed-to memory is not touched in any way.  Managing the pointer is
+       *  the user's responsibility.
+       */
+      void
+      clear() _GLIBCXX_NOEXCEPT
+      { _M_erase_at_end(begin()); }
+
+    protected:
+      // Internal constructor functions follow.
+
+#if __cplusplus < 201103L
+      // called by the range constructor to implement [23.1.1]/9
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 438. Ambiguity in the "do the right thing" clause
+      template<typename _Integer>
+	void
+	_M_initialize_dispatch(_Integer __n, _Integer __x, __true_type)
+	{
+	  _M_initialize_map(_S_check_init_len(static_cast<size_type>(__n),
+					      _M_get_Tp_allocator()));
+	  _M_fill_initialize(__x);
+	}
+
+      // called by the range constructor to implement [23.1.1]/9
+      template<typename _InputIterator>
+	void
+	_M_initialize_dispatch(_InputIterator __first, _InputIterator __last,
+			       __false_type)
+	{
+	  _M_range_initialize(__first, __last,
+			      std::__iterator_category(__first));
+	}
+#endif
+
+      static size_t
+      _S_check_init_len(size_t __n, const allocator_type& __a)
+      {
+	if (__n > _S_max_size(__a))
+	  __throw_length_error(
+	      __N("cannot create std::deque larger than max_size()"));
+	return __n;
+      }
+
+      static size_type
+      _S_max_size(const _Tp_alloc_type& __a) _GLIBCXX_NOEXCEPT
+      {
+	const size_t __diffmax = __gnu_cxx::__numeric_traits<ptrdiff_t>::__max;
+	const size_t __allocmax = _Alloc_traits::max_size(__a);
+	return (std::min)(__diffmax, __allocmax);
+      }
+
+      // called by the second initialize_dispatch above
+      ///@{
+      /**
+       *  @brief Fills the deque with whatever is in [first,last).
+       *  @param  __first  An input iterator.
+       *  @param  __last  An input iterator.
+       *  @return   Nothing.
+       *
+       *  If the iterators are actually forward iterators (or better), then the
+       *  memory layout can be done all at once.  Else we move forward using
+       *  push_back on each value from the iterator.
+       */
+      template<typename _InputIterator>
+	void
+	_M_range_initialize(_InputIterator __first, _InputIterator __last,
+			    std::input_iterator_tag);
+
+      // called by the second initialize_dispatch above
+      template<typename _ForwardIterator>
+	void
+	_M_range_initialize(_ForwardIterator __first, _ForwardIterator __last,
+			    std::forward_iterator_tag);
+      ///@}
+
+      /**
+       *  @brief Fills the %deque with copies of value.
+       *  @param  __value  Initial value.
+       *  @return   Nothing.
+       *  @pre _M_start and _M_finish have already been initialized,
+       *  but none of the %deque's elements have yet been constructed.
+       *
+       *  This function is called only when the user provides an explicit size
+       *  (with or without an explicit exemplar value).
+       */
+      void
+      _M_fill_initialize(const value_type& __value);
+
+#if __cplusplus >= 201103L
+      // called by deque(n).
+      void
+      _M_default_initialize();
+#endif
+
+      // Internal assign functions follow.  The *_aux functions do the actual
+      // assignment work for the range versions.
+
+#if __cplusplus < 201103L
+      // called by the range assign to implement [23.1.1]/9
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 438. Ambiguity in the "do the right thing" clause
+      template<typename _Integer>
+	void
+	_M_assign_dispatch(_Integer __n, _Integer __val, __true_type)
+	{ _M_fill_assign(__n, __val); }
+
+      // called by the range assign to implement [23.1.1]/9
+      template<typename _InputIterator>
+	void
+	_M_assign_dispatch(_InputIterator __first, _InputIterator __last,
+			   __false_type)
+	{ _M_assign_aux(__first, __last, std::__iterator_category(__first)); }
+#endif
+
+      // called by the second assign_dispatch above
+      template<typename _InputIterator>
+	void
+	_M_assign_aux(_InputIterator __first, _InputIterator __last,
+		      std::input_iterator_tag);
+
+      // called by the second assign_dispatch above
+      template<typename _ForwardIterator>
+	void
+	_M_assign_aux(_ForwardIterator __first, _ForwardIterator __last,
+		      std::forward_iterator_tag)
+	{
+	  const size_type __len = std::distance(__first, __last);
+	  if (__len > size())
+	    {
+	      _ForwardIterator __mid = __first;
+	      std::advance(__mid, size());
+	      std::copy(__first, __mid, begin());
+	      _M_range_insert_aux(end(), __mid, __last,
+				  std::__iterator_category(__first));
+	    }
+	  else
+	    _M_erase_at_end(std::copy(__first, __last, begin()));
+	}
+
+      // Called by assign(n,t), and the range assign when it turns out
+      // to be the same thing.
+      void
+      _M_fill_assign(size_type __n, const value_type& __val)
+      {
+	if (__n > size())
+	  {
+	    std::fill(begin(), end(), __val);
+	    _M_fill_insert(end(), __n - size(), __val);
+	  }
+	else
+	  {
+	    _M_erase_at_end(begin() + difference_type(__n));
+	    std::fill(begin(), end(), __val);
+	  }
+      }
+
+      ///@{
+      /// Helper functions for push_* and pop_*.
+#if __cplusplus < 201103L
+      void _M_push_back_aux(const value_type&);
+
+      void _M_push_front_aux(const value_type&);
+#else
+      template<typename... _Args>
+	void _M_push_back_aux(_Args&&... __args);
+
+      template<typename... _Args>
+	void _M_push_front_aux(_Args&&... __args);
+#endif
+
+      void _M_pop_back_aux();
+
+      void _M_pop_front_aux();
+      ///@}
+
+      // Internal insert functions follow.  The *_aux functions do the actual
+      // insertion work when all shortcuts fail.
+
+#if __cplusplus < 201103L
+      // called by the range insert to implement [23.1.1]/9
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 438. Ambiguity in the "do the right thing" clause
+      template<typename _Integer>
+	void
+	_M_insert_dispatch(iterator __pos,
+			   _Integer __n, _Integer __x, __true_type)
+	{ _M_fill_insert(__pos, __n, __x); }
+
+      // called by the range insert to implement [23.1.1]/9
+      template<typename _InputIterator>
+	void
+	_M_insert_dispatch(iterator __pos,
+			   _InputIterator __first, _InputIterator __last,
+			   __false_type)
+	{
+	  _M_range_insert_aux(__pos, __first, __last,
+			      std::__iterator_category(__first));
+	}
+#endif
+
+      // called by the second insert_dispatch above
+      template<typename _InputIterator>
+	void
+	_M_range_insert_aux(iterator __pos, _InputIterator __first,
+			    _InputIterator __last, std::input_iterator_tag);
+
+      // called by the second insert_dispatch above
+      template<typename _ForwardIterator>
+	void
+	_M_range_insert_aux(iterator __pos, _ForwardIterator __first,
+			    _ForwardIterator __last, std::forward_iterator_tag);
+
+      // Called by insert(p,n,x), and the range insert when it turns out to be
+      // the same thing.  Can use fill functions in optimal situations,
+      // otherwise passes off to insert_aux(p,n,x).
+      void
+      _M_fill_insert(iterator __pos, size_type __n, const value_type& __x);
+
+      // called by insert(p,x)
+#if __cplusplus < 201103L
+      iterator
+      _M_insert_aux(iterator __pos, const value_type& __x);
+#else
+      template<typename... _Args>
+	iterator
+	_M_insert_aux(iterator __pos, _Args&&... __args);
+#endif
+
+      // called by insert(p,n,x) via fill_insert
+      void
+      _M_insert_aux(iterator __pos, size_type __n, const value_type& __x);
+
+      // called by range_insert_aux for forward iterators
+      template<typename _ForwardIterator>
+	void
+	_M_insert_aux(iterator __pos,
+		      _ForwardIterator __first, _ForwardIterator __last,
+		      size_type __n);
+
+
+      // Internal erase functions follow.
+
+      void
+      _M_destroy_data_aux(iterator __first, iterator __last);
+
+      // Called by ~deque().
+      // NB: Doesn't deallocate the nodes.
+      template<typename _Alloc1>
+	void
+	_M_destroy_data(iterator __first, iterator __last, const _Alloc1&)
+	{ _M_destroy_data_aux(__first, __last); }
+
+      void
+      _M_destroy_data(iterator __first, iterator __last,
+		      const std::allocator<_Tp>&)
+      {
+	if (!__has_trivial_destructor(value_type))
+	  _M_destroy_data_aux(__first, __last);
+      }
+
+      // Called by erase(q1, q2).
+      void
+      _M_erase_at_begin(iterator __pos)
+      {
+	_M_destroy_data(begin(), __pos, _M_get_Tp_allocator());
+	_M_destroy_nodes(this->_M_impl._M_start._M_node, __pos._M_node);
+	this->_M_impl._M_start = __pos;
+      }
+
+      // Called by erase(q1, q2), resize(), clear(), _M_assign_aux,
+      // _M_fill_assign, operator=.
+      void
+      _M_erase_at_end(iterator __pos)
+      {
+	_M_destroy_data(__pos, end(), _M_get_Tp_allocator());
+	_M_destroy_nodes(__pos._M_node + 1,
+			 this->_M_impl._M_finish._M_node + 1);
+	this->_M_impl._M_finish = __pos;
+      }
+
+      iterator
+      _M_erase(iterator __pos);
+
+      iterator
+      _M_erase(iterator __first, iterator __last);
+
+#if __cplusplus >= 201103L
+      // Called by resize(sz).
+      void
+      _M_default_append(size_type __n);
+
+      bool
+      _M_shrink_to_fit();
+#endif
+
+      ///@{
+      /// Memory-handling helpers for the previous internal insert functions.
+      iterator
+      _M_reserve_elements_at_front(size_type __n)
+      {
+	const size_type __vacancies = this->_M_impl._M_start._M_cur
+				      - this->_M_impl._M_start._M_first;
+	if (__n > __vacancies)
+	  _M_new_elements_at_front(__n - __vacancies);
+	return this->_M_impl._M_start - difference_type(__n);
+      }
+
+      iterator
+      _M_reserve_elements_at_back(size_type __n)
+      {
+	const size_type __vacancies = (this->_M_impl._M_finish._M_last
+				       - this->_M_impl._M_finish._M_cur) - 1;
+	if (__n > __vacancies)
+	  _M_new_elements_at_back(__n - __vacancies);
+	return this->_M_impl._M_finish + difference_type(__n);
+      }
+
+      void
+      _M_new_elements_at_front(size_type __new_elements);
+
+      void
+      _M_new_elements_at_back(size_type __new_elements);
+      ///@}
+
+
+      ///@{
+      /**
+       *  @brief Memory-handling helpers for the major %map.
+       *
+       *  Makes sure the _M_map has space for new nodes.  Does not
+       *  actually add the nodes.  Can invalidate _M_map pointers.
+       *  (And consequently, %deque iterators.)
+       */
+      void
+      _M_reserve_map_at_back(size_type __nodes_to_add = 1)
+      {
+	if (__nodes_to_add + 1 > this->_M_impl._M_map_size
+	    - (this->_M_impl._M_finish._M_node - this->_M_impl._M_map))
+	  _M_reallocate_map(__nodes_to_add, false);
+      }
+
+      void
+      _M_reserve_map_at_front(size_type __nodes_to_add = 1)
+      {
+	if (__nodes_to_add > size_type(this->_M_impl._M_start._M_node
+				       - this->_M_impl._M_map))
+	  _M_reallocate_map(__nodes_to_add, true);
+      }
+
+      void
+      _M_reallocate_map(size_type __nodes_to_add, bool __add_at_front);
+      ///@}
+
+#if __cplusplus >= 201103L
+      // Constant-time, nothrow move assignment when source object's memory
+      // can be moved because the allocators are equal.
+      void
+      _M_move_assign1(deque&& __x, /* always equal: */ true_type) noexcept
+      {
+	this->_M_impl._M_swap_data(__x._M_impl);
+	__x.clear();
+	std::__alloc_on_move(_M_get_Tp_allocator(), __x._M_get_Tp_allocator());
+      }
+
+      // When the allocators are not equal the operation could throw, because
+      // we might need to allocate a new map for __x after moving from it
+      // or we might need to allocate new elements for *this.
+      void
+      _M_move_assign1(deque&& __x, /* always equal: */ false_type)
+      {
+	if (_M_get_Tp_allocator() == __x._M_get_Tp_allocator())
+	  return _M_move_assign1(std::move(__x), true_type());
+
+	constexpr bool __move_storage =
+	  _Alloc_traits::_S_propagate_on_move_assign();
+	_M_move_assign2(std::move(__x), __bool_constant<__move_storage>());
+      }
+
+      // Destroy all elements and deallocate all memory, then replace
+      // with elements created from __args.
+      template<typename... _Args>
+      void
+      _M_replace_map(_Args&&... __args)
+      {
+	// Create new data first, so if allocation fails there are no effects.
+	deque __newobj(std::forward<_Args>(__args)...);
+	// Free existing storage using existing allocator.
+	clear();
+	_M_deallocate_node(*begin()._M_node); // one node left after clear()
+	_M_deallocate_map(this->_M_impl._M_map, this->_M_impl._M_map_size);
+	this->_M_impl._M_map = nullptr;
+	this->_M_impl._M_map_size = 0;
+	// Take ownership of replacement memory.
+	this->_M_impl._M_swap_data(__newobj._M_impl);
+      }
+
+      // Do move assignment when the allocator propagates.
+      void
+      _M_move_assign2(deque&& __x, /* propagate: */ true_type)
+      {
+	// Make a copy of the original allocator state.
+	auto __alloc = __x._M_get_Tp_allocator();
+	// The allocator propagates so storage can be moved from __x,
+	// leaving __x in a valid empty state with a moved-from allocator.
+	_M_replace_map(std::move(__x));
+	// Move the corresponding allocator state too.
+	_M_get_Tp_allocator() = std::move(__alloc);
+      }
+
+      // Do move assignment when it may not be possible to move source
+      // object's memory, resulting in a linear-time operation.
+      void
+      _M_move_assign2(deque&& __x, /* propagate: */ false_type)
+      {
+	if (__x._M_get_Tp_allocator() == this->_M_get_Tp_allocator())
+	  {
+	    // The allocators are equal so storage can be moved from __x,
+	    // leaving __x in a valid empty state with its current allocator.
+	    _M_replace_map(std::move(__x), __x.get_allocator());
+	  }
+	else
+	  {
+	    // The rvalue's allocator cannot be moved and is not equal,
+	    // so we need to individually move each element.
+	    _M_assign_aux(std::make_move_iterator(__x.begin()),
+			  std::make_move_iterator(__x.end()),
+			  std::random_access_iterator_tag());
+	    __x.clear();
+	  }
+      }
+#endif
+    };
+
+#if __cpp_deduction_guides >= 201606
+  template<typename _InputIterator, typename _ValT
+	     = typename iterator_traits<_InputIterator>::value_type,
+	   typename _Allocator = allocator<_ValT>,
+	   typename = _RequireInputIter<_InputIterator>,
+	   typename = _RequireAllocator<_Allocator>>
+    deque(_InputIterator, _InputIterator, _Allocator = _Allocator())
+      -> deque<_ValT, _Allocator>;
+#endif
+
+  /**
+   *  @brief  Deque equality comparison.
+   *  @param  __x  A %deque.
+   *  @param  __y  A %deque of the same type as @a __x.
+   *  @return  True iff the size and elements of the deques are equal.
+   *
+   *  This is an equivalence relation.  It is linear in the size of the
+   *  deques.  Deques are considered equivalent if their sizes are equal,
+   *  and if corresponding elements compare equal.
+  */
+  template<typename _Tp, typename _Alloc>
+    _GLIBCXX_NODISCARD
+    inline bool
+    operator==(const deque<_Tp, _Alloc>& __x, const deque<_Tp, _Alloc>& __y)
+    { return __x.size() == __y.size()
+	     && std::equal(__x.begin(), __x.end(), __y.begin()); }
+
+#if __cpp_lib_three_way_comparison
+  /**
+   *  @brief  Deque ordering relation.
+   *  @param  __x  A `deque`.
+   *  @param  __y  A `deque` of the same type as `__x`.
+   *  @return  A value indicating whether `__x` is less than, equal to,
+   *           greater than, or incomparable with `__y`.
+   *
+   *  See `std::lexicographical_compare_three_way()` for how the determination
+   *  is made. This operator is used to synthesize relational operators like
+   *  `<` and `>=` etc.
+  */
+  template<typename _Tp, typename _Alloc>
+    [[nodiscard]]
+    inline __detail::__synth3way_t<_Tp>
+    operator<=>(const deque<_Tp, _Alloc>& __x, const deque<_Tp, _Alloc>& __y)
+    {
+      return std::lexicographical_compare_three_way(__x.begin(), __x.end(),
+						    __y.begin(), __y.end(),
+						    __detail::__synth3way);
+    }
+#else
+  /**
+   *  @brief  Deque ordering relation.
+   *  @param  __x  A %deque.
+   *  @param  __y  A %deque of the same type as @a __x.
+   *  @return  True iff @a x is lexicographically less than @a __y.
+   *
+   *  This is a total ordering relation.  It is linear in the size of the
+   *  deques.  The elements must be comparable with @c <.
+   *
+   *  See std::lexicographical_compare() for how the determination is made.
+  */
+  template<typename _Tp, typename _Alloc>
+    _GLIBCXX_NODISCARD
+    inline bool
+    operator<(const deque<_Tp, _Alloc>& __x, const deque<_Tp, _Alloc>& __y)
+    { return std::lexicographical_compare(__x.begin(), __x.end(),
+					  __y.begin(), __y.end()); }
+
+  /// Based on operator==
+  template<typename _Tp, typename _Alloc>
+    _GLIBCXX_NODISCARD
+    inline bool
+    operator!=(const deque<_Tp, _Alloc>& __x, const deque<_Tp, _Alloc>& __y)
+    { return !(__x == __y); }
+
+  /// Based on operator<
+  template<typename _Tp, typename _Alloc>
+    _GLIBCXX_NODISCARD
+    inline bool
+    operator>(const deque<_Tp, _Alloc>& __x, const deque<_Tp, _Alloc>& __y)
+    { return __y < __x; }
+
+  /// Based on operator<
+  template<typename _Tp, typename _Alloc>
+    _GLIBCXX_NODISCARD
+    inline bool
+    operator<=(const deque<_Tp, _Alloc>& __x, const deque<_Tp, _Alloc>& __y)
+    { return !(__y < __x); }
+
+  /// Based on operator<
+  template<typename _Tp, typename _Alloc>
+    _GLIBCXX_NODISCARD
+    inline bool
+    operator>=(const deque<_Tp, _Alloc>& __x, const deque<_Tp, _Alloc>& __y)
+    { return !(__x < __y); }
+#endif // three-way comparison
+
+  /// See std::deque::swap().
+  template<typename _Tp, typename _Alloc>
+    inline void
+    swap(deque<_Tp,_Alloc>& __x, deque<_Tp,_Alloc>& __y)
+    _GLIBCXX_NOEXCEPT_IF(noexcept(__x.swap(__y)))
+    { __x.swap(__y); }
+
+#undef _GLIBCXX_DEQUE_BUF_SIZE
+
+_GLIBCXX_END_NAMESPACE_CONTAINER
+
+#if __cplusplus >= 201103L
+  // std::allocator is safe, but it is not the only allocator
+  // for which this is valid.
+  template<class _Tp>
+    struct __is_bitwise_relocatable<_GLIBCXX_STD_C::deque<_Tp>>
+    : true_type { };
+#endif
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif /* _STL_DEQUE_H */
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@@ -0,0 +1,1441 @@
+// Functor implementations -*- C++ -*-
+
+// Copyright (C) 2001-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/*
+ *
+ * Copyright (c) 1994
+ * Hewlett-Packard Company
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Hewlett-Packard Company makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ *
+ *
+ * Copyright (c) 1996-1998
+ * Silicon Graphics Computer Systems, Inc.
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Silicon Graphics makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ */
+
+/** @file bits/stl_function.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{functional}
+ */
+
+#ifndef _STL_FUNCTION_H
+#define _STL_FUNCTION_H 1
+
+#if __cplusplus > 201103L
+#include <bits/move.h>
+#endif
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  // 20.3.1 base classes
+  /** @defgroup functors Function Objects
+   *  @ingroup utilities
+   *
+   *  Function objects, or _functors_, are objects with an `operator()`
+   *  defined and accessible.  They can be passed as arguments to algorithm
+   *  templates and used in place of a function pointer.  Not only is the
+   *  resulting expressiveness of the library increased, but the generated
+   *  code can be more efficient than what you might write by hand.  When we
+   *  refer to _functors_, then, generally we include function pointers in
+   *  the description as well.
+   *
+   *  Often, functors are only created as temporaries passed to algorithm
+   *  calls, rather than being created as named variables.
+   *
+   *  Two examples taken from the standard itself follow.  To perform a
+   *  by-element addition of two vectors `a` and `b` containing `double`,
+   *  and put the result in `a`, use
+   *  \code
+   *  transform (a.begin(), a.end(), b.begin(), a.begin(), plus<double>());
+   *  \endcode
+   *  To negate every element in `a`, use
+   *  \code
+   *  transform(a.begin(), a.end(), a.begin(), negate<double>());
+   *  \endcode
+   *  The addition and negation functions will usually be inlined directly.
+   *
+   *  An _adaptable function object_ is one which provides nested typedefs
+   *  `result_type` and either `argument_type` (for a unary function) or
+   *  `first_argument_type` and `second_argument_type` (for a binary function).
+   *  Those typedefs are used by function object adaptors such as `bind2nd`.
+   *  The standard library provides two class templates, `unary_function` and
+   *  `binary_function`, which define those typedefs and so can be used as
+   *  base classes of adaptable function objects.
+   *
+   *  Since C++11 the use of function object adaptors has been superseded by
+   *  more powerful tools such as lambda expressions, `function<>`, and more
+   *  powerful type deduction (using `auto` and `decltype`). The helpers for
+   *  defining adaptable function objects are deprecated since C++11, and no
+   *  longer part of the standard library since C++17. However, they are still
+   *  defined and used by libstdc++ after C++17, as a conforming extension.
+   *
+   *  @{
+   */
+
+  /**
+   *  Helper for defining adaptable unary function objects.
+   *  @deprecated Deprecated in C++11, no longer in the standard since C++17.
+   */
+  template<typename _Arg, typename _Result>
+    struct unary_function
+    {
+      /// @c argument_type is the type of the argument
+      typedef _Arg 	argument_type;   
+
+      /// @c result_type is the return type
+      typedef _Result 	result_type;  
+    } _GLIBCXX11_DEPRECATED;
+
+  /**
+   *  Helper for defining adaptable binary function objects.
+   *  @deprecated Deprecated in C++11, no longer in the standard since C++17.
+   */
+  template<typename _Arg1, typename _Arg2, typename _Result>
+    struct binary_function
+    {
+      /// @c first_argument_type is the type of the first argument
+      typedef _Arg1 	first_argument_type; 
+
+      /// @c second_argument_type is the type of the second argument
+      typedef _Arg2 	second_argument_type;
+
+      /// @c result_type is the return type
+      typedef _Result 	result_type;
+    } _GLIBCXX11_DEPRECATED;
+  /** @}  */
+
+  // 20.3.2 arithmetic
+
+  /** @defgroup arithmetic_functors Arithmetic Function Object Classes
+   *  @ingroup functors
+   *
+   *  The library provides function objects for basic arithmetic operations.
+   *  See the documentation for @link functors function objects @endlink
+   *  for examples of their use.
+   *
+   *  @{
+   */
+
+#if __cplusplus > 201103L
+  struct __is_transparent;  // undefined
+
+  template<typename _Tp = void>
+    struct plus;
+
+  template<typename _Tp = void>
+    struct minus;
+
+  template<typename _Tp = void>
+    struct multiplies;
+
+  template<typename _Tp = void>
+    struct divides;
+
+  template<typename _Tp = void>
+    struct modulus;
+
+  template<typename _Tp = void>
+    struct negate;
+#endif
+
+// Ignore warnings about unary_function and binary_function.
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+
+  /// One of the @link arithmetic_functors math functors@endlink.
+  template<typename _Tp>
+    struct plus : public binary_function<_Tp, _Tp, _Tp>
+    {
+      /// Returns the sum
+      _GLIBCXX14_CONSTEXPR
+      _Tp
+      operator()(const _Tp& __x, const _Tp& __y) const
+      { return __x + __y; }
+    };
+
+  /// One of the @link arithmetic_functors math functors@endlink.
+  template<typename _Tp>
+    struct minus : public binary_function<_Tp, _Tp, _Tp>
+    {
+      _GLIBCXX14_CONSTEXPR
+      _Tp
+      operator()(const _Tp& __x, const _Tp& __y) const
+      { return __x - __y; }
+    };
+
+  /// One of the @link arithmetic_functors math functors@endlink.
+  template<typename _Tp>
+    struct multiplies : public binary_function<_Tp, _Tp, _Tp>
+    {
+      _GLIBCXX14_CONSTEXPR
+      _Tp
+      operator()(const _Tp& __x, const _Tp& __y) const
+      { return __x * __y; }
+    };
+
+  /// One of the @link arithmetic_functors math functors@endlink.
+  template<typename _Tp>
+    struct divides : public binary_function<_Tp, _Tp, _Tp>
+    {
+      _GLIBCXX14_CONSTEXPR
+      _Tp
+      operator()(const _Tp& __x, const _Tp& __y) const
+      { return __x / __y; }
+    };
+
+  /// One of the @link arithmetic_functors math functors@endlink.
+  template<typename _Tp>
+    struct modulus : public binary_function<_Tp, _Tp, _Tp>
+    {
+      _GLIBCXX14_CONSTEXPR
+      _Tp
+      operator()(const _Tp& __x, const _Tp& __y) const
+      { return __x % __y; }
+    };
+
+  /// One of the @link arithmetic_functors math functors@endlink.
+  template<typename _Tp>
+    struct negate : public unary_function<_Tp, _Tp>
+    {
+      _GLIBCXX14_CONSTEXPR
+      _Tp
+      operator()(const _Tp& __x) const
+      { return -__x; }
+    };
+#pragma GCC diagnostic pop
+
+#if __cplusplus > 201103L
+
+#define __cpp_lib_transparent_operators 201510L
+
+  template<>
+    struct plus<void>
+    {
+      template <typename _Tp, typename _Up>
+	_GLIBCXX14_CONSTEXPR
+	auto
+	operator()(_Tp&& __t, _Up&& __u) const
+	noexcept(noexcept(std::forward<_Tp>(__t) + std::forward<_Up>(__u)))
+	-> decltype(std::forward<_Tp>(__t) + std::forward<_Up>(__u))
+	{ return std::forward<_Tp>(__t) + std::forward<_Up>(__u); }
+
+      typedef __is_transparent is_transparent;
+    };
+
+  /// One of the @link arithmetic_functors math functors@endlink.
+  template<>
+    struct minus<void>
+    {
+      template <typename _Tp, typename _Up>
+	_GLIBCXX14_CONSTEXPR
+	auto
+	operator()(_Tp&& __t, _Up&& __u) const
+	noexcept(noexcept(std::forward<_Tp>(__t) - std::forward<_Up>(__u)))
+	-> decltype(std::forward<_Tp>(__t) - std::forward<_Up>(__u))
+	{ return std::forward<_Tp>(__t) - std::forward<_Up>(__u); }
+
+      typedef __is_transparent is_transparent;
+    };
+
+  /// One of the @link arithmetic_functors math functors@endlink.
+  template<>
+    struct multiplies<void>
+    {
+      template <typename _Tp, typename _Up>
+	_GLIBCXX14_CONSTEXPR
+	auto
+	operator()(_Tp&& __t, _Up&& __u) const
+	noexcept(noexcept(std::forward<_Tp>(__t) * std::forward<_Up>(__u)))
+	-> decltype(std::forward<_Tp>(__t) * std::forward<_Up>(__u))
+	{ return std::forward<_Tp>(__t) * std::forward<_Up>(__u); }
+
+      typedef __is_transparent is_transparent;
+    };
+
+  /// One of the @link arithmetic_functors math functors@endlink.
+  template<>
+    struct divides<void>
+    {
+      template <typename _Tp, typename _Up>
+	_GLIBCXX14_CONSTEXPR
+	auto
+	operator()(_Tp&& __t, _Up&& __u) const
+	noexcept(noexcept(std::forward<_Tp>(__t) / std::forward<_Up>(__u)))
+	-> decltype(std::forward<_Tp>(__t) / std::forward<_Up>(__u))
+	{ return std::forward<_Tp>(__t) / std::forward<_Up>(__u); }
+
+      typedef __is_transparent is_transparent;
+    };
+
+  /// One of the @link arithmetic_functors math functors@endlink.
+  template<>
+    struct modulus<void>
+    {
+      template <typename _Tp, typename _Up>
+	_GLIBCXX14_CONSTEXPR
+	auto
+	operator()(_Tp&& __t, _Up&& __u) const
+	noexcept(noexcept(std::forward<_Tp>(__t) % std::forward<_Up>(__u)))
+	-> decltype(std::forward<_Tp>(__t) % std::forward<_Up>(__u))
+	{ return std::forward<_Tp>(__t) % std::forward<_Up>(__u); }
+
+      typedef __is_transparent is_transparent;
+    };
+
+  /// One of the @link arithmetic_functors math functors@endlink.
+  template<>
+    struct negate<void>
+    {
+      template <typename _Tp>
+	_GLIBCXX14_CONSTEXPR
+	auto
+	operator()(_Tp&& __t) const
+	noexcept(noexcept(-std::forward<_Tp>(__t)))
+	-> decltype(-std::forward<_Tp>(__t))
+	{ return -std::forward<_Tp>(__t); }
+
+      typedef __is_transparent is_transparent;
+    };
+#endif
+  /** @}  */
+
+  // 20.3.3 comparisons
+  /** @defgroup comparison_functors Comparison Classes
+   *  @ingroup functors
+   *
+   *  The library provides six wrapper functors for all the basic comparisons
+   *  in C++, like @c <.
+   *
+   *  @{
+   */
+#if __cplusplus > 201103L
+  template<typename _Tp = void>
+    struct equal_to;
+
+  template<typename _Tp = void>
+    struct not_equal_to;
+
+  template<typename _Tp = void>
+    struct greater;
+
+  template<typename _Tp = void>
+    struct less;
+
+  template<typename _Tp = void>
+    struct greater_equal;
+
+  template<typename _Tp = void>
+    struct less_equal;
+#endif
+
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+
+  /// One of the @link comparison_functors comparison functors@endlink.
+  template<typename _Tp>
+    struct equal_to : public binary_function<_Tp, _Tp, bool>
+    {
+      _GLIBCXX14_CONSTEXPR
+      bool
+      operator()(const _Tp& __x, const _Tp& __y) const
+      { return __x == __y; }
+    };
+
+  /// One of the @link comparison_functors comparison functors@endlink.
+  template<typename _Tp>
+    struct not_equal_to : public binary_function<_Tp, _Tp, bool>
+    {
+      _GLIBCXX14_CONSTEXPR
+      bool
+      operator()(const _Tp& __x, const _Tp& __y) const
+      { return __x != __y; }
+    };
+
+  /// One of the @link comparison_functors comparison functors@endlink.
+  template<typename _Tp>
+    struct greater : public binary_function<_Tp, _Tp, bool>
+    {
+      _GLIBCXX14_CONSTEXPR
+      bool
+      operator()(const _Tp& __x, const _Tp& __y) const
+      { return __x > __y; }
+    };
+
+  /// One of the @link comparison_functors comparison functors@endlink.
+  template<typename _Tp>
+    struct less : public binary_function<_Tp, _Tp, bool>
+    {
+      _GLIBCXX14_CONSTEXPR
+      bool
+      operator()(const _Tp& __x, const _Tp& __y) const
+      { return __x < __y; }
+    };
+
+  /// One of the @link comparison_functors comparison functors@endlink.
+  template<typename _Tp>
+    struct greater_equal : public binary_function<_Tp, _Tp, bool>
+    {
+      _GLIBCXX14_CONSTEXPR
+      bool
+      operator()(const _Tp& __x, const _Tp& __y) const
+      { return __x >= __y; }
+    };
+
+  /// One of the @link comparison_functors comparison functors@endlink.
+  template<typename _Tp>
+    struct less_equal : public binary_function<_Tp, _Tp, bool>
+    {
+      _GLIBCXX14_CONSTEXPR
+      bool
+      operator()(const _Tp& __x, const _Tp& __y) const
+      { return __x <= __y; }
+    };
+
+  // Partial specialization of std::greater for pointers.
+  template<typename _Tp>
+    struct greater<_Tp*> : public binary_function<_Tp*, _Tp*, bool>
+    {
+      _GLIBCXX14_CONSTEXPR bool
+      operator()(_Tp* __x, _Tp* __y) const _GLIBCXX_NOTHROW
+      {
+#if __cplusplus >= 201402L
+	if (std::__is_constant_evaluated())
+	  return __x > __y;
+#endif
+	return (__UINTPTR_TYPE__)__x > (__UINTPTR_TYPE__)__y;
+      }
+    };
+
+  // Partial specialization of std::less for pointers.
+  template<typename _Tp>
+    struct less<_Tp*> : public binary_function<_Tp*, _Tp*, bool>
+    {
+      _GLIBCXX14_CONSTEXPR bool
+      operator()(_Tp* __x, _Tp* __y) const _GLIBCXX_NOTHROW
+      {
+#if __cplusplus >= 201402L
+	if (std::__is_constant_evaluated())
+	  return __x < __y;
+#endif
+	return (__UINTPTR_TYPE__)__x < (__UINTPTR_TYPE__)__y;
+      }
+    };
+
+  // Partial specialization of std::greater_equal for pointers.
+  template<typename _Tp>
+    struct greater_equal<_Tp*> : public binary_function<_Tp*, _Tp*, bool>
+    {
+      _GLIBCXX14_CONSTEXPR bool
+      operator()(_Tp* __x, _Tp* __y) const _GLIBCXX_NOTHROW
+      {
+#if __cplusplus >= 201402L
+	if (std::__is_constant_evaluated())
+	  return __x >= __y;
+#endif
+	return (__UINTPTR_TYPE__)__x >= (__UINTPTR_TYPE__)__y;
+      }
+    };
+
+  // Partial specialization of std::less_equal for pointers.
+  template<typename _Tp>
+    struct less_equal<_Tp*> : public binary_function<_Tp*, _Tp*, bool>
+    {
+      _GLIBCXX14_CONSTEXPR bool
+      operator()(_Tp* __x, _Tp* __y) const _GLIBCXX_NOTHROW
+      {
+#if __cplusplus >= 201402L
+	if (std::__is_constant_evaluated())
+	  return __x <= __y;
+#endif
+	return (__UINTPTR_TYPE__)__x <= (__UINTPTR_TYPE__)__y;
+      }
+    };
+#pragma GCC diagnostic pop
+
+#if __cplusplus >= 201402L
+  /// One of the @link comparison_functors comparison functors@endlink.
+  template<>
+    struct equal_to<void>
+    {
+      template <typename _Tp, typename _Up>
+	constexpr auto
+	operator()(_Tp&& __t, _Up&& __u) const
+	noexcept(noexcept(std::forward<_Tp>(__t) == std::forward<_Up>(__u)))
+	-> decltype(std::forward<_Tp>(__t) == std::forward<_Up>(__u))
+	{ return std::forward<_Tp>(__t) == std::forward<_Up>(__u); }
+
+      typedef __is_transparent is_transparent;
+    };
+
+  /// One of the @link comparison_functors comparison functors@endlink.
+  template<>
+    struct not_equal_to<void>
+    {
+      template <typename _Tp, typename _Up>
+	constexpr auto
+	operator()(_Tp&& __t, _Up&& __u) const
+	noexcept(noexcept(std::forward<_Tp>(__t) != std::forward<_Up>(__u)))
+	-> decltype(std::forward<_Tp>(__t) != std::forward<_Up>(__u))
+	{ return std::forward<_Tp>(__t) != std::forward<_Up>(__u); }
+
+      typedef __is_transparent is_transparent;
+    };
+
+  /// One of the @link comparison_functors comparison functors@endlink.
+  template<>
+    struct greater<void>
+    {
+      template <typename _Tp, typename _Up>
+	constexpr auto
+	operator()(_Tp&& __t, _Up&& __u) const
+	noexcept(noexcept(std::forward<_Tp>(__t) > std::forward<_Up>(__u)))
+	-> decltype(std::forward<_Tp>(__t) > std::forward<_Up>(__u))
+	{
+	  return _S_cmp(std::forward<_Tp>(__t), std::forward<_Up>(__u),
+			__ptr_cmp<_Tp, _Up>{});
+	}
+
+      template<typename _Tp, typename _Up>
+	constexpr bool
+	operator()(_Tp* __t, _Up* __u) const noexcept
+	{ return greater<common_type_t<_Tp*, _Up*>>{}(__t, __u); }
+
+      typedef __is_transparent is_transparent;
+
+    private:
+      template <typename _Tp, typename _Up>
+	static constexpr decltype(auto)
+	_S_cmp(_Tp&& __t, _Up&& __u, false_type)
+	{ return std::forward<_Tp>(__t) > std::forward<_Up>(__u); }
+
+      template <typename _Tp, typename _Up>
+	static constexpr bool
+	_S_cmp(_Tp&& __t, _Up&& __u, true_type) noexcept
+	{
+	  return greater<const volatile void*>{}(
+	      static_cast<const volatile void*>(std::forward<_Tp>(__t)),
+	      static_cast<const volatile void*>(std::forward<_Up>(__u)));
+	}
+
+      // True if there is no viable operator> member function.
+      template<typename _Tp, typename _Up, typename = void>
+	struct __not_overloaded2 : true_type { };
+
+      // False if we can call T.operator>(U)
+      template<typename _Tp, typename _Up>
+	struct __not_overloaded2<_Tp, _Up, __void_t<
+	  decltype(std::declval<_Tp>().operator>(std::declval<_Up>()))>>
+	: false_type { };
+
+      // True if there is no overloaded operator> for these operands.
+      template<typename _Tp, typename _Up, typename = void>
+	struct __not_overloaded : __not_overloaded2<_Tp, _Up> { };
+
+      // False if we can call operator>(T,U)
+      template<typename _Tp, typename _Up>
+	struct __not_overloaded<_Tp, _Up, __void_t<
+	  decltype(operator>(std::declval<_Tp>(), std::declval<_Up>()))>>
+	: false_type { };
+
+      template<typename _Tp, typename _Up>
+	using __ptr_cmp = __and_<__not_overloaded<_Tp, _Up>,
+	      is_convertible<_Tp, const volatile void*>,
+	      is_convertible<_Up, const volatile void*>>;
+    };
+
+  /// One of the @link comparison_functors comparison functors@endlink.
+  template<>
+    struct less<void>
+    {
+      template <typename _Tp, typename _Up>
+	constexpr auto
+	operator()(_Tp&& __t, _Up&& __u) const
+	noexcept(noexcept(std::forward<_Tp>(__t) < std::forward<_Up>(__u)))
+	-> decltype(std::forward<_Tp>(__t) < std::forward<_Up>(__u))
+	{
+	  return _S_cmp(std::forward<_Tp>(__t), std::forward<_Up>(__u),
+			__ptr_cmp<_Tp, _Up>{});
+	}
+
+      template<typename _Tp, typename _Up>
+	constexpr bool
+	operator()(_Tp* __t, _Up* __u) const noexcept
+	{ return less<common_type_t<_Tp*, _Up*>>{}(__t, __u); }
+
+      typedef __is_transparent is_transparent;
+
+    private:
+      template <typename _Tp, typename _Up>
+	static constexpr decltype(auto)
+	_S_cmp(_Tp&& __t, _Up&& __u, false_type)
+	{ return std::forward<_Tp>(__t) < std::forward<_Up>(__u); }
+
+      template <typename _Tp, typename _Up>
+	static constexpr bool
+	_S_cmp(_Tp&& __t, _Up&& __u, true_type) noexcept
+	{
+	  return less<const volatile void*>{}(
+	      static_cast<const volatile void*>(std::forward<_Tp>(__t)),
+	      static_cast<const volatile void*>(std::forward<_Up>(__u)));
+	}
+
+      // True if there is no viable operator< member function.
+      template<typename _Tp, typename _Up, typename = void>
+	struct __not_overloaded2 : true_type { };
+
+      // False if we can call T.operator<(U)
+      template<typename _Tp, typename _Up>
+	struct __not_overloaded2<_Tp, _Up, __void_t<
+	  decltype(std::declval<_Tp>().operator<(std::declval<_Up>()))>>
+	: false_type { };
+
+      // True if there is no overloaded operator< for these operands.
+      template<typename _Tp, typename _Up, typename = void>
+	struct __not_overloaded : __not_overloaded2<_Tp, _Up> { };
+
+      // False if we can call operator<(T,U)
+      template<typename _Tp, typename _Up>
+	struct __not_overloaded<_Tp, _Up, __void_t<
+	  decltype(operator<(std::declval<_Tp>(), std::declval<_Up>()))>>
+	: false_type { };
+
+      template<typename _Tp, typename _Up>
+	using __ptr_cmp = __and_<__not_overloaded<_Tp, _Up>,
+	      is_convertible<_Tp, const volatile void*>,
+	      is_convertible<_Up, const volatile void*>>;
+    };
+
+  /// One of the @link comparison_functors comparison functors@endlink.
+  template<>
+    struct greater_equal<void>
+    {
+      template <typename _Tp, typename _Up>
+	constexpr auto
+	operator()(_Tp&& __t, _Up&& __u) const
+	noexcept(noexcept(std::forward<_Tp>(__t) >= std::forward<_Up>(__u)))
+	-> decltype(std::forward<_Tp>(__t) >= std::forward<_Up>(__u))
+	{
+	  return _S_cmp(std::forward<_Tp>(__t), std::forward<_Up>(__u),
+			__ptr_cmp<_Tp, _Up>{});
+	}
+
+      template<typename _Tp, typename _Up>
+	constexpr bool
+	operator()(_Tp* __t, _Up* __u) const noexcept
+	{ return greater_equal<common_type_t<_Tp*, _Up*>>{}(__t, __u); }
+
+      typedef __is_transparent is_transparent;
+
+    private:
+      template <typename _Tp, typename _Up>
+	static constexpr decltype(auto)
+	_S_cmp(_Tp&& __t, _Up&& __u, false_type)
+	{ return std::forward<_Tp>(__t) >= std::forward<_Up>(__u); }
+
+      template <typename _Tp, typename _Up>
+	static constexpr bool
+	_S_cmp(_Tp&& __t, _Up&& __u, true_type) noexcept
+	{
+	  return greater_equal<const volatile void*>{}(
+	      static_cast<const volatile void*>(std::forward<_Tp>(__t)),
+	      static_cast<const volatile void*>(std::forward<_Up>(__u)));
+	}
+
+      // True if there is no viable operator>= member function.
+      template<typename _Tp, typename _Up, typename = void>
+	struct __not_overloaded2 : true_type { };
+
+      // False if we can call T.operator>=(U)
+      template<typename _Tp, typename _Up>
+	struct __not_overloaded2<_Tp, _Up, __void_t<
+	  decltype(std::declval<_Tp>().operator>=(std::declval<_Up>()))>>
+	: false_type { };
+
+      // True if there is no overloaded operator>= for these operands.
+      template<typename _Tp, typename _Up, typename = void>
+	struct __not_overloaded : __not_overloaded2<_Tp, _Up> { };
+
+      // False if we can call operator>=(T,U)
+      template<typename _Tp, typename _Up>
+	struct __not_overloaded<_Tp, _Up, __void_t<
+	  decltype(operator>=(std::declval<_Tp>(), std::declval<_Up>()))>>
+	: false_type { };
+
+      template<typename _Tp, typename _Up>
+	using __ptr_cmp = __and_<__not_overloaded<_Tp, _Up>,
+	      is_convertible<_Tp, const volatile void*>,
+	      is_convertible<_Up, const volatile void*>>;
+    };
+
+  /// One of the @link comparison_functors comparison functors@endlink.
+  template<>
+    struct less_equal<void>
+    {
+      template <typename _Tp, typename _Up>
+	constexpr auto
+	operator()(_Tp&& __t, _Up&& __u) const
+	noexcept(noexcept(std::forward<_Tp>(__t) <= std::forward<_Up>(__u)))
+	-> decltype(std::forward<_Tp>(__t) <= std::forward<_Up>(__u))
+	{
+	  return _S_cmp(std::forward<_Tp>(__t), std::forward<_Up>(__u),
+			__ptr_cmp<_Tp, _Up>{});
+	}
+
+      template<typename _Tp, typename _Up>
+	constexpr bool
+	operator()(_Tp* __t, _Up* __u) const noexcept
+	{ return less_equal<common_type_t<_Tp*, _Up*>>{}(__t, __u); }
+
+      typedef __is_transparent is_transparent;
+
+    private:
+      template <typename _Tp, typename _Up>
+	static constexpr decltype(auto)
+	_S_cmp(_Tp&& __t, _Up&& __u, false_type)
+	{ return std::forward<_Tp>(__t) <= std::forward<_Up>(__u); }
+
+      template <typename _Tp, typename _Up>
+	static constexpr bool
+	_S_cmp(_Tp&& __t, _Up&& __u, true_type) noexcept
+	{
+	  return less_equal<const volatile void*>{}(
+	      static_cast<const volatile void*>(std::forward<_Tp>(__t)),
+	      static_cast<const volatile void*>(std::forward<_Up>(__u)));
+	}
+
+      // True if there is no viable operator<= member function.
+      template<typename _Tp, typename _Up, typename = void>
+	struct __not_overloaded2 : true_type { };
+
+      // False if we can call T.operator<=(U)
+      template<typename _Tp, typename _Up>
+	struct __not_overloaded2<_Tp, _Up, __void_t<
+	  decltype(std::declval<_Tp>().operator<=(std::declval<_Up>()))>>
+	: false_type { };
+
+      // True if there is no overloaded operator<= for these operands.
+      template<typename _Tp, typename _Up, typename = void>
+	struct __not_overloaded : __not_overloaded2<_Tp, _Up> { };
+
+      // False if we can call operator<=(T,U)
+      template<typename _Tp, typename _Up>
+	struct __not_overloaded<_Tp, _Up, __void_t<
+	  decltype(operator<=(std::declval<_Tp>(), std::declval<_Up>()))>>
+	: false_type { };
+
+      template<typename _Tp, typename _Up>
+	using __ptr_cmp = __and_<__not_overloaded<_Tp, _Up>,
+	      is_convertible<_Tp, const volatile void*>,
+	      is_convertible<_Up, const volatile void*>>;
+    };
+#endif // C++14
+  /** @}  */
+
+  // 20.3.4 logical operations
+  /** @defgroup logical_functors Boolean Operations Classes
+   *  @ingroup functors
+   *
+   *  The library provides function objects for the logical operations:
+   *  `&&`, `||`, and `!`.
+   *
+   *  @{
+   */
+#if __cplusplus > 201103L
+  template<typename _Tp = void>
+    struct logical_and;
+
+  template<typename _Tp = void>
+    struct logical_or;
+
+  template<typename _Tp = void>
+    struct logical_not;
+#endif
+
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+
+  /// One of the @link logical_functors Boolean operations functors@endlink.
+  template<typename _Tp>
+    struct logical_and : public binary_function<_Tp, _Tp, bool>
+    {
+      _GLIBCXX14_CONSTEXPR
+      bool
+      operator()(const _Tp& __x, const _Tp& __y) const
+      { return __x && __y; }
+    };
+
+  /// One of the @link logical_functors Boolean operations functors@endlink.
+  template<typename _Tp>
+    struct logical_or : public binary_function<_Tp, _Tp, bool>
+    {
+      _GLIBCXX14_CONSTEXPR
+      bool
+      operator()(const _Tp& __x, const _Tp& __y) const
+      { return __x || __y; }
+    };
+
+  /// One of the @link logical_functors Boolean operations functors@endlink.
+  template<typename _Tp>
+    struct logical_not : public unary_function<_Tp, bool>
+    {
+      _GLIBCXX14_CONSTEXPR
+      bool
+      operator()(const _Tp& __x) const
+      { return !__x; }
+    };
+#pragma GCC diagnostic pop
+
+#if __cplusplus > 201103L
+  /// One of the @link logical_functors Boolean operations functors@endlink.
+  template<>
+    struct logical_and<void>
+    {
+      template <typename _Tp, typename _Up>
+	_GLIBCXX14_CONSTEXPR
+	auto
+	operator()(_Tp&& __t, _Up&& __u) const
+	noexcept(noexcept(std::forward<_Tp>(__t) && std::forward<_Up>(__u)))
+	-> decltype(std::forward<_Tp>(__t) && std::forward<_Up>(__u))
+	{ return std::forward<_Tp>(__t) && std::forward<_Up>(__u); }
+
+      typedef __is_transparent is_transparent;
+    };
+
+  /// One of the @link logical_functors Boolean operations functors@endlink.
+  template<>
+    struct logical_or<void>
+    {
+      template <typename _Tp, typename _Up>
+	_GLIBCXX14_CONSTEXPR
+	auto
+	operator()(_Tp&& __t, _Up&& __u) const
+	noexcept(noexcept(std::forward<_Tp>(__t) || std::forward<_Up>(__u)))
+	-> decltype(std::forward<_Tp>(__t) || std::forward<_Up>(__u))
+	{ return std::forward<_Tp>(__t) || std::forward<_Up>(__u); }
+
+      typedef __is_transparent is_transparent;
+    };
+
+  /// One of the @link logical_functors Boolean operations functors@endlink.
+  template<>
+    struct logical_not<void>
+    {
+      template <typename _Tp>
+	_GLIBCXX14_CONSTEXPR
+	auto
+	operator()(_Tp&& __t) const
+	noexcept(noexcept(!std::forward<_Tp>(__t)))
+	-> decltype(!std::forward<_Tp>(__t))
+	{ return !std::forward<_Tp>(__t); }
+
+      typedef __is_transparent is_transparent;
+    };
+#endif
+  /** @}  */
+
+#if __cplusplus > 201103L
+  template<typename _Tp = void>
+    struct bit_and;
+
+  template<typename _Tp = void>
+    struct bit_or;
+
+  template<typename _Tp = void>
+    struct bit_xor;
+
+  template<typename _Tp = void>
+    struct bit_not;
+#endif
+
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+
+  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+  // DR 660. Missing Bitwise Operations.
+  template<typename _Tp>
+    struct bit_and : public binary_function<_Tp, _Tp, _Tp>
+    {
+      _GLIBCXX14_CONSTEXPR
+      _Tp
+      operator()(const _Tp& __x, const _Tp& __y) const
+      { return __x & __y; }
+    };
+
+  template<typename _Tp>
+    struct bit_or : public binary_function<_Tp, _Tp, _Tp>
+    {
+      _GLIBCXX14_CONSTEXPR
+      _Tp
+      operator()(const _Tp& __x, const _Tp& __y) const
+      { return __x | __y; }
+    };
+
+  template<typename _Tp>
+    struct bit_xor : public binary_function<_Tp, _Tp, _Tp>
+    {
+      _GLIBCXX14_CONSTEXPR
+      _Tp
+      operator()(const _Tp& __x, const _Tp& __y) const
+      { return __x ^ __y; }
+    };
+
+  template<typename _Tp>
+    struct bit_not : public unary_function<_Tp, _Tp>
+    {
+    _GLIBCXX14_CONSTEXPR
+      _Tp
+      operator()(const _Tp& __x) const
+      { return ~__x; }
+    };
+#pragma GCC diagnostic pop
+
+#if __cplusplus > 201103L
+  template <>
+    struct bit_and<void>
+    {
+      template <typename _Tp, typename _Up>
+	_GLIBCXX14_CONSTEXPR
+	auto
+	operator()(_Tp&& __t, _Up&& __u) const
+	noexcept(noexcept(std::forward<_Tp>(__t) & std::forward<_Up>(__u)))
+	-> decltype(std::forward<_Tp>(__t) & std::forward<_Up>(__u))
+	{ return std::forward<_Tp>(__t) & std::forward<_Up>(__u); }
+
+      typedef __is_transparent is_transparent;
+    };
+
+  template <>
+    struct bit_or<void>
+    {
+      template <typename _Tp, typename _Up>
+	_GLIBCXX14_CONSTEXPR
+	auto
+	operator()(_Tp&& __t, _Up&& __u) const
+	noexcept(noexcept(std::forward<_Tp>(__t) | std::forward<_Up>(__u)))
+	-> decltype(std::forward<_Tp>(__t) | std::forward<_Up>(__u))
+	{ return std::forward<_Tp>(__t) | std::forward<_Up>(__u); }
+
+      typedef __is_transparent is_transparent;
+    };
+
+  template <>
+    struct bit_xor<void>
+    {
+      template <typename _Tp, typename _Up>
+	_GLIBCXX14_CONSTEXPR
+	auto
+	operator()(_Tp&& __t, _Up&& __u) const
+	noexcept(noexcept(std::forward<_Tp>(__t) ^ std::forward<_Up>(__u)))
+	-> decltype(std::forward<_Tp>(__t) ^ std::forward<_Up>(__u))
+	{ return std::forward<_Tp>(__t) ^ std::forward<_Up>(__u); }
+
+      typedef __is_transparent is_transparent;
+    };
+
+  template <>
+    struct bit_not<void>
+    {
+      template <typename _Tp>
+	_GLIBCXX14_CONSTEXPR
+	auto
+	operator()(_Tp&& __t) const
+	noexcept(noexcept(~std::forward<_Tp>(__t)))
+	-> decltype(~std::forward<_Tp>(__t))
+	{ return ~std::forward<_Tp>(__t); }
+
+      typedef __is_transparent is_transparent;
+    };
+#endif // C++14
+
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+
+  // 20.3.5 negators
+  /** @defgroup negators Negators
+   *  @ingroup functors
+   *
+   *  The function templates `not1` and `not2` are function object adaptors,
+   *  which each take a predicate functor and wrap it in an instance of
+   *  `unary_negate` or `binary_negate`, respectively.  Those classes are
+   *  functors whose `operator()` evaluates the wrapped predicate function
+   *  and then returns the negation of the result.
+   *
+   *  For example, given a vector of integers and a trivial predicate,
+   *  \code
+   *  struct IntGreaterThanThree
+   *    : public std::unary_function<int, bool>
+   *  {
+   *      bool operator() (int x) const { return x > 3; }
+   *  };
+   *
+   *  std::find_if (v.begin(), v.end(), not1(IntGreaterThanThree()));
+   *  \endcode
+   *  The call to `find_if` will locate the first index (i) of `v` for which
+   *  `!(v[i] > 3)` is true.
+   *
+   *  The not1/unary_negate combination works on predicates taking a single
+   *  argument.  The not2/binary_negate combination works on predicates taking
+   *  two arguments.
+   *
+   *  @deprecated Deprecated in C++17, no longer in the standard since C++20.
+   *  Use `not_fn` instead.
+   *
+   *  @{
+   */
+  /// One of the @link negators negation functors@endlink.
+  template<typename _Predicate>
+    class _GLIBCXX17_DEPRECATED unary_negate
+    : public unary_function<typename _Predicate::argument_type, bool>
+    {
+    protected:
+      _Predicate _M_pred;
+
+    public:
+      _GLIBCXX14_CONSTEXPR
+      explicit
+      unary_negate(const _Predicate& __x) : _M_pred(__x) { }
+
+      _GLIBCXX14_CONSTEXPR
+      bool
+      operator()(const typename _Predicate::argument_type& __x) const
+      { return !_M_pred(__x); }
+    };
+
+  /// One of the @link negators negation functors@endlink.
+  template<typename _Predicate>
+    _GLIBCXX17_DEPRECATED_SUGGEST("std::not_fn")
+    _GLIBCXX14_CONSTEXPR
+    inline unary_negate<_Predicate>
+    not1(const _Predicate& __pred)
+    { return unary_negate<_Predicate>(__pred); }
+
+  /// One of the @link negators negation functors@endlink.
+  template<typename _Predicate>
+    class _GLIBCXX17_DEPRECATED binary_negate
+    : public binary_function<typename _Predicate::first_argument_type,
+			     typename _Predicate::second_argument_type, bool>
+    {
+    protected:
+      _Predicate _M_pred;
+
+    public:
+      _GLIBCXX14_CONSTEXPR
+      explicit
+      binary_negate(const _Predicate& __x) : _M_pred(__x) { }
+
+      _GLIBCXX14_CONSTEXPR
+      bool
+      operator()(const typename _Predicate::first_argument_type& __x,
+		 const typename _Predicate::second_argument_type& __y) const
+      { return !_M_pred(__x, __y); }
+    };
+
+  /// One of the @link negators negation functors@endlink.
+  template<typename _Predicate>
+    _GLIBCXX17_DEPRECATED_SUGGEST("std::not_fn")
+    _GLIBCXX14_CONSTEXPR
+    inline binary_negate<_Predicate>
+    not2(const _Predicate& __pred)
+    { return binary_negate<_Predicate>(__pred); }
+  /** @}  */
+
+  // 20.3.7 adaptors pointers functions
+  /** @defgroup pointer_adaptors Adaptors for pointers to functions
+   *  @ingroup functors
+   *
+   *  The advantage of function objects over pointers to functions is that
+   *  the objects in the standard library declare nested typedefs describing
+   *  their argument and result types with uniform names (e.g., `result_type`
+   *  from the base classes `unary_function` and `binary_function`).
+   *  Sometimes those typedefs are required, not just optional.
+   *
+   *  Adaptors are provided to turn pointers to unary (single-argument) and
+   *  binary (double-argument) functions into function objects.  The
+   *  long-winded functor `pointer_to_unary_function` is constructed with a
+   *  function pointer `f`, and its `operator()` called with argument `x`
+   *  returns `f(x)`.  The functor `pointer_to_binary_function` does the same
+   *  thing, but with a double-argument `f` and `operator()`.
+   *
+   *  The function `ptr_fun` takes a pointer-to-function `f` and constructs
+   *  an instance of the appropriate functor.
+   *
+   *  @deprecated Deprecated in C++11, no longer in the standard since C++17.
+   *
+   *  @{
+   */
+  /// One of the @link pointer_adaptors adaptors for function pointers@endlink.
+  template<typename _Arg, typename _Result>
+    class pointer_to_unary_function : public unary_function<_Arg, _Result>
+    {
+    protected:
+      _Result (*_M_ptr)(_Arg);
+
+    public:
+      pointer_to_unary_function() { }
+
+      explicit
+      pointer_to_unary_function(_Result (*__x)(_Arg))
+      : _M_ptr(__x) { }
+
+      _Result
+      operator()(_Arg __x) const
+      { return _M_ptr(__x); }
+    } _GLIBCXX11_DEPRECATED;
+
+  /// One of the @link pointer_adaptors adaptors for function pointers@endlink.
+  template<typename _Arg, typename _Result>
+    _GLIBCXX11_DEPRECATED_SUGGEST("std::function")
+    inline pointer_to_unary_function<_Arg, _Result>
+    ptr_fun(_Result (*__x)(_Arg))
+    { return pointer_to_unary_function<_Arg, _Result>(__x); }
+
+  /// One of the @link pointer_adaptors adaptors for function pointers@endlink.
+  template<typename _Arg1, typename _Arg2, typename _Result>
+    class pointer_to_binary_function
+    : public binary_function<_Arg1, _Arg2, _Result>
+    {
+    protected:
+      _Result (*_M_ptr)(_Arg1, _Arg2);
+
+    public:
+      pointer_to_binary_function() { }
+
+      explicit
+      pointer_to_binary_function(_Result (*__x)(_Arg1, _Arg2))
+      : _M_ptr(__x) { }
+
+      _Result
+      operator()(_Arg1 __x, _Arg2 __y) const
+      { return _M_ptr(__x, __y); }
+    } _GLIBCXX11_DEPRECATED;
+
+  /// One of the @link pointer_adaptors adaptors for function pointers@endlink.
+  template<typename _Arg1, typename _Arg2, typename _Result>
+    _GLIBCXX11_DEPRECATED_SUGGEST("std::function")
+    inline pointer_to_binary_function<_Arg1, _Arg2, _Result>
+    ptr_fun(_Result (*__x)(_Arg1, _Arg2))
+    { return pointer_to_binary_function<_Arg1, _Arg2, _Result>(__x); }
+  /** @}  */
+
+  template<typename _Tp>
+    struct _Identity
+    : public unary_function<_Tp, _Tp>
+    {
+      _Tp&
+      operator()(_Tp& __x) const
+      { return __x; }
+
+      const _Tp&
+      operator()(const _Tp& __x) const
+      { return __x; }
+    };
+
+  // Partial specialization, avoids confusing errors in e.g. std::set<const T>.
+  template<typename _Tp> struct _Identity<const _Tp> : _Identity<_Tp> { };
+
+  template<typename _Pair>
+    struct _Select1st
+    : public unary_function<_Pair, typename _Pair::first_type>
+    {
+      typename _Pair::first_type&
+      operator()(_Pair& __x) const
+      { return __x.first; }
+
+      const typename _Pair::first_type&
+      operator()(const _Pair& __x) const
+      { return __x.first; }
+
+#if __cplusplus >= 201103L
+      template<typename _Pair2>
+        typename _Pair2::first_type&
+        operator()(_Pair2& __x) const
+        { return __x.first; }
+
+      template<typename _Pair2>
+        const typename _Pair2::first_type&
+        operator()(const _Pair2& __x) const
+        { return __x.first; }
+#endif
+    };
+
+  template<typename _Pair>
+    struct _Select2nd
+    : public unary_function<_Pair, typename _Pair::second_type>
+    {
+      typename _Pair::second_type&
+      operator()(_Pair& __x) const
+      { return __x.second; }
+
+      const typename _Pair::second_type&
+      operator()(const _Pair& __x) const
+      { return __x.second; }
+    };
+
+  // 20.3.8 adaptors pointers members
+  /** @defgroup ptrmem_adaptors Adaptors for pointers to members
+   *  @ingroup functors
+   *
+   *  There are a total of 8 = 2^3 function objects in this family.
+   *   (1) Member functions taking no arguments vs member functions taking
+   *        one argument.
+   *   (2) Call through pointer vs call through reference.
+   *   (3) Const vs non-const member function.
+   *
+   *  All of this complexity is in the function objects themselves.  You can
+   *   ignore it by using the helper function `mem_fun` and `mem_fun_ref`,
+   *   which create whichever type of adaptor is appropriate.
+   *
+   *  @deprecated Deprecated in C++11, no longer in the standard since C++17.
+   *  Use `mem_fn` instead.
+   *
+   *  @{
+   */
+  /// One of the @link ptrmem_adaptors adaptors for member pointers@endlink.
+  template<typename _Ret, typename _Tp>
+    class mem_fun_t : public unary_function<_Tp*, _Ret>
+    {
+    public:
+      explicit
+      mem_fun_t(_Ret (_Tp::*__pf)())
+      : _M_f(__pf) { }
+
+      _Ret
+      operator()(_Tp* __p) const
+      { return (__p->*_M_f)(); }
+
+    private:
+      _Ret (_Tp::*_M_f)();
+    } _GLIBCXX11_DEPRECATED;
+
+  /// One of the @link ptrmem_adaptors adaptors for member pointers@endlink.
+  template<typename _Ret, typename _Tp>
+    class const_mem_fun_t : public unary_function<const _Tp*, _Ret>
+    {
+    public:
+      explicit
+      const_mem_fun_t(_Ret (_Tp::*__pf)() const)
+      : _M_f(__pf) { }
+
+      _Ret
+      operator()(const _Tp* __p) const
+      { return (__p->*_M_f)(); }
+
+    private:
+      _Ret (_Tp::*_M_f)() const;
+    } _GLIBCXX11_DEPRECATED;
+
+  /// One of the @link ptrmem_adaptors adaptors for member pointers@endlink.
+  template<typename _Ret, typename _Tp>
+    class mem_fun_ref_t : public unary_function<_Tp, _Ret>
+    {
+    public:
+      explicit
+      mem_fun_ref_t(_Ret (_Tp::*__pf)())
+      : _M_f(__pf) { }
+
+      _Ret
+      operator()(_Tp& __r) const
+      { return (__r.*_M_f)(); }
+
+    private:
+      _Ret (_Tp::*_M_f)();
+    } _GLIBCXX11_DEPRECATED;
+
+  /// One of the @link ptrmem_adaptors adaptors for member pointers@endlink.
+  template<typename _Ret, typename _Tp>
+    class const_mem_fun_ref_t : public unary_function<_Tp, _Ret>
+    {
+    public:
+      explicit
+      const_mem_fun_ref_t(_Ret (_Tp::*__pf)() const)
+      : _M_f(__pf) { }
+
+      _Ret
+      operator()(const _Tp& __r) const
+      { return (__r.*_M_f)(); }
+
+    private:
+      _Ret (_Tp::*_M_f)() const;
+    } _GLIBCXX11_DEPRECATED;
+
+  /// One of the @link ptrmem_adaptors adaptors for member pointers@endlink.
+  template<typename _Ret, typename _Tp, typename _Arg>
+    class mem_fun1_t : public binary_function<_Tp*, _Arg, _Ret>
+    {
+    public:
+      explicit
+      mem_fun1_t(_Ret (_Tp::*__pf)(_Arg))
+      : _M_f(__pf) { }
+
+      _Ret
+      operator()(_Tp* __p, _Arg __x) const
+      { return (__p->*_M_f)(__x); }
+
+    private:
+      _Ret (_Tp::*_M_f)(_Arg);
+    } _GLIBCXX11_DEPRECATED;
+
+  /// One of the @link ptrmem_adaptors adaptors for member pointers@endlink.
+  template<typename _Ret, typename _Tp, typename _Arg>
+    class const_mem_fun1_t : public binary_function<const _Tp*, _Arg, _Ret>
+    {
+    public:
+      explicit
+      const_mem_fun1_t(_Ret (_Tp::*__pf)(_Arg) const)
+      : _M_f(__pf) { }
+
+      _Ret
+      operator()(const _Tp* __p, _Arg __x) const
+      { return (__p->*_M_f)(__x); }
+
+    private:
+      _Ret (_Tp::*_M_f)(_Arg) const;
+    } _GLIBCXX11_DEPRECATED;
+
+  /// One of the @link ptrmem_adaptors adaptors for member pointers@endlink.
+  template<typename _Ret, typename _Tp, typename _Arg>
+    class mem_fun1_ref_t : public binary_function<_Tp, _Arg, _Ret>
+    {
+    public:
+      explicit
+      mem_fun1_ref_t(_Ret (_Tp::*__pf)(_Arg))
+      : _M_f(__pf) { }
+
+      _Ret
+      operator()(_Tp& __r, _Arg __x) const
+      { return (__r.*_M_f)(__x); }
+
+    private:
+      _Ret (_Tp::*_M_f)(_Arg);
+    } _GLIBCXX11_DEPRECATED;
+
+  /// One of the @link ptrmem_adaptors adaptors for member pointers@endlink.
+  template<typename _Ret, typename _Tp, typename _Arg>
+    class const_mem_fun1_ref_t : public binary_function<_Tp, _Arg, _Ret>
+    {
+    public:
+      explicit
+      const_mem_fun1_ref_t(_Ret (_Tp::*__pf)(_Arg) const)
+      : _M_f(__pf) { }
+
+      _Ret
+      operator()(const _Tp& __r, _Arg __x) const
+      { return (__r.*_M_f)(__x); }
+
+    private:
+      _Ret (_Tp::*_M_f)(_Arg) const;
+    } _GLIBCXX11_DEPRECATED;
+
+  // Mem_fun adaptor helper functions.  There are only two:
+  // mem_fun and mem_fun_ref.
+  template<typename _Ret, typename _Tp>
+    _GLIBCXX11_DEPRECATED_SUGGEST("std::mem_fn")
+    inline mem_fun_t<_Ret, _Tp>
+    mem_fun(_Ret (_Tp::*__f)())
+    { return mem_fun_t<_Ret, _Tp>(__f); }
+
+  template<typename _Ret, typename _Tp>
+    _GLIBCXX11_DEPRECATED_SUGGEST("std::mem_fn")
+    inline const_mem_fun_t<_Ret, _Tp>
+    mem_fun(_Ret (_Tp::*__f)() const)
+    { return const_mem_fun_t<_Ret, _Tp>(__f); }
+
+  template<typename _Ret, typename _Tp>
+    _GLIBCXX11_DEPRECATED_SUGGEST("std::mem_fn")
+    inline mem_fun_ref_t<_Ret, _Tp>
+    mem_fun_ref(_Ret (_Tp::*__f)())
+    { return mem_fun_ref_t<_Ret, _Tp>(__f); }
+
+  template<typename _Ret, typename _Tp>
+    _GLIBCXX11_DEPRECATED_SUGGEST("std::mem_fn")
+    inline const_mem_fun_ref_t<_Ret, _Tp>
+    mem_fun_ref(_Ret (_Tp::*__f)() const)
+    { return const_mem_fun_ref_t<_Ret, _Tp>(__f); }
+
+  template<typename _Ret, typename _Tp, typename _Arg>
+    _GLIBCXX11_DEPRECATED_SUGGEST("std::mem_fn")
+    inline mem_fun1_t<_Ret, _Tp, _Arg>
+    mem_fun(_Ret (_Tp::*__f)(_Arg))
+    { return mem_fun1_t<_Ret, _Tp, _Arg>(__f); }
+
+  template<typename _Ret, typename _Tp, typename _Arg>
+    _GLIBCXX11_DEPRECATED_SUGGEST("std::mem_fn")
+    inline const_mem_fun1_t<_Ret, _Tp, _Arg>
+    mem_fun(_Ret (_Tp::*__f)(_Arg) const)
+    { return const_mem_fun1_t<_Ret, _Tp, _Arg>(__f); }
+
+  template<typename _Ret, typename _Tp, typename _Arg>
+    _GLIBCXX11_DEPRECATED_SUGGEST("std::mem_fn")
+    inline mem_fun1_ref_t<_Ret, _Tp, _Arg>
+    mem_fun_ref(_Ret (_Tp::*__f)(_Arg))
+    { return mem_fun1_ref_t<_Ret, _Tp, _Arg>(__f); }
+
+  template<typename _Ret, typename _Tp, typename _Arg>
+    _GLIBCXX11_DEPRECATED_SUGGEST("std::mem_fn")
+    inline const_mem_fun1_ref_t<_Ret, _Tp, _Arg>
+    mem_fun_ref(_Ret (_Tp::*__f)(_Arg) const)
+    { return const_mem_fun1_ref_t<_Ret, _Tp, _Arg>(__f); }
+#pragma GCC diagnostic pop
+
+  /** @}  */
+
+#if __cplusplus >= 201402L
+  template<typename _Func, typename _SfinaeType, typename = __void_t<>>
+    struct __has_is_transparent
+    { };
+
+  template<typename _Func, typename _SfinaeType>
+    struct __has_is_transparent<_Func, _SfinaeType,
+				__void_t<typename _Func::is_transparent>>
+    { typedef void type; };
+
+  template<typename _Func, typename _SfinaeType>
+    using __has_is_transparent_t
+      = typename __has_is_transparent<_Func, _SfinaeType>::type;
+#endif
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#if (__cplusplus < 201103L) || _GLIBCXX_USE_DEPRECATED
+# include <backward/binders.h>
+#endif
+
+#endif /* _STL_FUNCTION_H */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stl_function.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stl_function.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stl_heap.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stl_heap.h
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stl_heap.h
@@ -0,0 +1,584 @@
+// Heap implementation -*- C++ -*-
+
+// Copyright (C) 2001-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/*
+ *
+ * Copyright (c) 1994
+ * Hewlett-Packard Company
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Hewlett-Packard Company makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ *
+ * Copyright (c) 1997
+ * Silicon Graphics Computer Systems, Inc.
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Silicon Graphics makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ */
+
+/** @file bits/stl_heap.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{queue}
+ */
+
+#ifndef _STL_HEAP_H
+#define _STL_HEAP_H 1
+
+#include <debug/debug.h>
+#include <bits/move.h>
+#include <bits/predefined_ops.h>
+#include <bits/stl_iterator_base_funcs.h>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /**
+   * @defgroup heap_algorithms Heap
+   * @ingroup sorting_algorithms
+   */
+
+  template<typename _RandomAccessIterator, typename _Distance,
+	   typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    _Distance
+    __is_heap_until(_RandomAccessIterator __first, _Distance __n,
+		    _Compare& __comp)
+    {
+      _Distance __parent = 0;
+      for (_Distance __child = 1; __child < __n; ++__child)
+	{
+	  if (__comp(__first + __parent, __first + __child))
+	    return __child;
+	  if ((__child & 1) == 0)
+	    ++__parent;
+	}
+      return __n;
+    }
+
+  // __is_heap, a predicate testing whether or not a range is a heap.
+  // This function is an extension, not part of the C++ standard.
+  template<typename _RandomAccessIterator, typename _Distance>
+    _GLIBCXX20_CONSTEXPR
+    inline bool
+    __is_heap(_RandomAccessIterator __first, _Distance __n)
+    {
+      __gnu_cxx::__ops::_Iter_less_iter __comp;
+      return std::__is_heap_until(__first, __n, __comp) == __n;
+    }
+
+  template<typename _RandomAccessIterator, typename _Compare,
+	   typename _Distance>
+    _GLIBCXX20_CONSTEXPR
+    inline bool
+    __is_heap(_RandomAccessIterator __first, _Compare __comp, _Distance __n)
+    {
+      typedef __decltype(__comp) _Cmp;
+      __gnu_cxx::__ops::_Iter_comp_iter<_Cmp> __cmp(_GLIBCXX_MOVE(__comp));
+      return std::__is_heap_until(__first, __n, __cmp) == __n;
+    }
+
+  template<typename _RandomAccessIterator>
+    _GLIBCXX20_CONSTEXPR
+    inline bool
+    __is_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
+    { return std::__is_heap(__first, std::distance(__first, __last)); }
+
+  template<typename _RandomAccessIterator, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    inline bool
+    __is_heap(_RandomAccessIterator __first, _RandomAccessIterator __last,
+	      _Compare __comp)
+    {
+      return std::__is_heap(__first, _GLIBCXX_MOVE(__comp),
+			    std::distance(__first, __last));
+    }
+
+  // Heap-manipulation functions: push_heap, pop_heap, make_heap, sort_heap,
+  // + is_heap and is_heap_until in C++0x.
+
+  template<typename _RandomAccessIterator, typename _Distance, typename _Tp,
+	   typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    void
+    __push_heap(_RandomAccessIterator __first,
+		_Distance __holeIndex, _Distance __topIndex, _Tp __value,
+		_Compare& __comp)
+    {
+      _Distance __parent = (__holeIndex - 1) / 2;
+      while (__holeIndex > __topIndex && __comp(__first + __parent, __value))
+	{
+	  *(__first + __holeIndex) = _GLIBCXX_MOVE(*(__first + __parent));
+	  __holeIndex = __parent;
+	  __parent = (__holeIndex - 1) / 2;
+	}
+      *(__first + __holeIndex) = _GLIBCXX_MOVE(__value);
+    }
+
+  /**
+   *  @brief  Push an element onto a heap.
+   *  @param  __first  Start of heap.
+   *  @param  __last   End of heap + element.
+   *  @ingroup heap_algorithms
+   *
+   *  This operation pushes the element at last-1 onto the valid heap
+   *  over the range [__first,__last-1).  After completion,
+   *  [__first,__last) is a valid heap.
+  */
+  template<typename _RandomAccessIterator>
+    _GLIBCXX20_CONSTEXPR
+    inline void
+    push_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
+    {
+      typedef typename iterator_traits<_RandomAccessIterator>::value_type
+	  _ValueType;
+      typedef typename iterator_traits<_RandomAccessIterator>::difference_type
+	  _DistanceType;
+
+      // concept requirements
+      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
+	    _RandomAccessIterator>)
+      __glibcxx_function_requires(_LessThanComparableConcept<_ValueType>)
+      __glibcxx_requires_valid_range(__first, __last);
+      __glibcxx_requires_irreflexive(__first, __last);
+      __glibcxx_requires_heap(__first, __last - 1);
+
+      __gnu_cxx::__ops::_Iter_less_val __comp;
+      _ValueType __value = _GLIBCXX_MOVE(*(__last - 1));
+      std::__push_heap(__first, _DistanceType((__last - __first) - 1),
+		       _DistanceType(0), _GLIBCXX_MOVE(__value), __comp);
+    }
+
+  /**
+   *  @brief  Push an element onto a heap using comparison functor.
+   *  @param  __first  Start of heap.
+   *  @param  __last   End of heap + element.
+   *  @param  __comp   Comparison functor.
+   *  @ingroup heap_algorithms
+   *
+   *  This operation pushes the element at __last-1 onto the valid
+   *  heap over the range [__first,__last-1).  After completion,
+   *  [__first,__last) is a valid heap.  Compare operations are
+   *  performed using comp.
+  */
+  template<typename _RandomAccessIterator, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    inline void
+    push_heap(_RandomAccessIterator __first, _RandomAccessIterator __last,
+	      _Compare __comp)
+    {
+      typedef typename iterator_traits<_RandomAccessIterator>::value_type
+	  _ValueType;
+      typedef typename iterator_traits<_RandomAccessIterator>::difference_type
+	  _DistanceType;
+
+      // concept requirements
+      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
+	    _RandomAccessIterator>)
+      __glibcxx_requires_valid_range(__first, __last);
+      __glibcxx_requires_irreflexive_pred(__first, __last, __comp);
+      __glibcxx_requires_heap_pred(__first, __last - 1, __comp);
+
+      __decltype(__gnu_cxx::__ops::__iter_comp_val(_GLIBCXX_MOVE(__comp)))
+	__cmp(_GLIBCXX_MOVE(__comp));
+      _ValueType __value = _GLIBCXX_MOVE(*(__last - 1));
+      std::__push_heap(__first, _DistanceType((__last - __first) - 1),
+		       _DistanceType(0), _GLIBCXX_MOVE(__value), __cmp);
+    }
+
+  template<typename _RandomAccessIterator, typename _Distance,
+	   typename _Tp, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    void
+    __adjust_heap(_RandomAccessIterator __first, _Distance __holeIndex,
+		  _Distance __len, _Tp __value, _Compare __comp)
+    {
+      const _Distance __topIndex = __holeIndex;
+      _Distance __secondChild = __holeIndex;
+      while (__secondChild < (__len - 1) / 2)
+	{
+	  __secondChild = 2 * (__secondChild + 1);
+	  if (__comp(__first + __secondChild,
+		     __first + (__secondChild - 1)))
+	    __secondChild--;
+	  *(__first + __holeIndex) = _GLIBCXX_MOVE(*(__first + __secondChild));
+	  __holeIndex = __secondChild;
+	}
+      if ((__len & 1) == 0 && __secondChild == (__len - 2) / 2)
+	{
+	  __secondChild = 2 * (__secondChild + 1);
+	  *(__first + __holeIndex) = _GLIBCXX_MOVE(*(__first
+						     + (__secondChild - 1)));
+	  __holeIndex = __secondChild - 1;
+	}
+      __decltype(__gnu_cxx::__ops::__iter_comp_val(_GLIBCXX_MOVE(__comp)))
+	__cmp(_GLIBCXX_MOVE(__comp));
+      std::__push_heap(__first, __holeIndex, __topIndex,
+		       _GLIBCXX_MOVE(__value), __cmp);
+    }
+
+  template<typename _RandomAccessIterator, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    inline void
+    __pop_heap(_RandomAccessIterator __first, _RandomAccessIterator __last,
+	       _RandomAccessIterator __result, _Compare& __comp)
+    {
+      typedef typename iterator_traits<_RandomAccessIterator>::value_type
+	_ValueType;
+      typedef typename iterator_traits<_RandomAccessIterator>::difference_type
+	_DistanceType;
+
+      _ValueType __value = _GLIBCXX_MOVE(*__result);
+      *__result = _GLIBCXX_MOVE(*__first);
+      std::__adjust_heap(__first, _DistanceType(0),
+			 _DistanceType(__last - __first),
+			 _GLIBCXX_MOVE(__value), __comp);
+    }
+
+  /**
+   *  @brief  Pop an element off a heap.
+   *  @param  __first  Start of heap.
+   *  @param  __last   End of heap.
+   *  @pre    [__first, __last) is a valid, non-empty range.
+   *  @ingroup heap_algorithms
+   *
+   *  This operation pops the top of the heap.  The elements __first
+   *  and __last-1 are swapped and [__first,__last-1) is made into a
+   *  heap.
+  */
+  template<typename _RandomAccessIterator>
+    _GLIBCXX20_CONSTEXPR
+    inline void
+    pop_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
+	    _RandomAccessIterator>)
+      __glibcxx_function_requires(_LessThanComparableConcept<
+	typename iterator_traits<_RandomAccessIterator>::value_type>)
+      __glibcxx_requires_non_empty_range(__first, __last);
+      __glibcxx_requires_valid_range(__first, __last);
+      __glibcxx_requires_irreflexive(__first, __last);
+      __glibcxx_requires_heap(__first, __last);
+
+      if (__last - __first > 1)
+	{
+	  --__last;
+	  __gnu_cxx::__ops::_Iter_less_iter __comp;
+	  std::__pop_heap(__first, __last, __last, __comp);
+	}
+    }
+
+  /**
+   *  @brief  Pop an element off a heap using comparison functor.
+   *  @param  __first  Start of heap.
+   *  @param  __last   End of heap.
+   *  @param  __comp   Comparison functor to use.
+   *  @ingroup heap_algorithms
+   *
+   *  This operation pops the top of the heap.  The elements __first
+   *  and __last-1 are swapped and [__first,__last-1) is made into a
+   *  heap.  Comparisons are made using comp.
+  */
+  template<typename _RandomAccessIterator, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    inline void
+    pop_heap(_RandomAccessIterator __first,
+	     _RandomAccessIterator __last, _Compare __comp)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
+	    _RandomAccessIterator>)
+      __glibcxx_requires_valid_range(__first, __last);
+      __glibcxx_requires_irreflexive_pred(__first, __last, __comp);
+      __glibcxx_requires_non_empty_range(__first, __last);
+      __glibcxx_requires_heap_pred(__first, __last, __comp);
+
+      if (__last - __first > 1)
+	{
+	  typedef __decltype(__comp) _Cmp;
+	  __gnu_cxx::__ops::_Iter_comp_iter<_Cmp> __cmp(_GLIBCXX_MOVE(__comp));
+	  --__last;
+	  std::__pop_heap(__first, __last, __last, __cmp);
+	}
+    }
+
+  template<typename _RandomAccessIterator, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    void
+    __make_heap(_RandomAccessIterator __first, _RandomAccessIterator __last,
+		_Compare& __comp)
+    {
+      typedef typename iterator_traits<_RandomAccessIterator>::value_type
+	  _ValueType;
+      typedef typename iterator_traits<_RandomAccessIterator>::difference_type
+	  _DistanceType;
+
+      if (__last - __first < 2)
+	return;
+
+      const _DistanceType __len = __last - __first;
+      _DistanceType __parent = (__len - 2) / 2;
+      while (true)
+	{
+	  _ValueType __value = _GLIBCXX_MOVE(*(__first + __parent));
+	  std::__adjust_heap(__first, __parent, __len, _GLIBCXX_MOVE(__value),
+			     __comp);
+	  if (__parent == 0)
+	    return;
+	  __parent--;
+	}
+    }
+  
+  /**
+   *  @brief  Construct a heap over a range.
+   *  @param  __first  Start of heap.
+   *  @param  __last   End of heap.
+   *  @ingroup heap_algorithms
+   *
+   *  This operation makes the elements in [__first,__last) into a heap.
+  */
+  template<typename _RandomAccessIterator>
+    _GLIBCXX20_CONSTEXPR
+    inline void
+    make_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
+	    _RandomAccessIterator>)
+      __glibcxx_function_requires(_LessThanComparableConcept<
+	    typename iterator_traits<_RandomAccessIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+      __glibcxx_requires_irreflexive(__first, __last);
+
+      __gnu_cxx::__ops::_Iter_less_iter __comp;
+      std::__make_heap(__first, __last, __comp);
+    }
+
+  /**
+   *  @brief  Construct a heap over a range using comparison functor.
+   *  @param  __first  Start of heap.
+   *  @param  __last   End of heap.
+   *  @param  __comp   Comparison functor to use.
+   *  @ingroup heap_algorithms
+   *
+   *  This operation makes the elements in [__first,__last) into a heap.
+   *  Comparisons are made using __comp.
+  */
+  template<typename _RandomAccessIterator, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    inline void
+    make_heap(_RandomAccessIterator __first, _RandomAccessIterator __last,
+	      _Compare __comp)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
+	    _RandomAccessIterator>)
+      __glibcxx_requires_valid_range(__first, __last);
+      __glibcxx_requires_irreflexive_pred(__first, __last, __comp);
+
+      typedef __decltype(__comp) _Cmp;
+      __gnu_cxx::__ops::_Iter_comp_iter<_Cmp> __cmp(_GLIBCXX_MOVE(__comp));
+      std::__make_heap(__first, __last, __cmp);
+    }
+
+  template<typename _RandomAccessIterator, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    void
+    __sort_heap(_RandomAccessIterator __first, _RandomAccessIterator __last,
+		_Compare& __comp)
+    {
+      while (__last - __first > 1)
+	{
+	  --__last;
+	  std::__pop_heap(__first, __last, __last, __comp);
+	}
+    }
+
+  /**
+   *  @brief  Sort a heap.
+   *  @param  __first  Start of heap.
+   *  @param  __last   End of heap.
+   *  @ingroup heap_algorithms
+   *
+   *  This operation sorts the valid heap in the range [__first,__last).
+  */
+  template<typename _RandomAccessIterator>
+    _GLIBCXX20_CONSTEXPR
+    inline void
+    sort_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
+	    _RandomAccessIterator>)
+      __glibcxx_function_requires(_LessThanComparableConcept<
+	    typename iterator_traits<_RandomAccessIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+      __glibcxx_requires_irreflexive(__first, __last);
+      __glibcxx_requires_heap(__first, __last);
+
+      __gnu_cxx::__ops::_Iter_less_iter __comp;
+      std::__sort_heap(__first, __last, __comp);
+    }
+
+  /**
+   *  @brief  Sort a heap using comparison functor.
+   *  @param  __first  Start of heap.
+   *  @param  __last   End of heap.
+   *  @param  __comp   Comparison functor to use.
+   *  @ingroup heap_algorithms
+   *
+   *  This operation sorts the valid heap in the range [__first,__last).
+   *  Comparisons are made using __comp.
+  */
+  template<typename _RandomAccessIterator, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    inline void
+    sort_heap(_RandomAccessIterator __first, _RandomAccessIterator __last,
+	      _Compare __comp)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
+	    _RandomAccessIterator>)
+      __glibcxx_requires_valid_range(__first, __last);
+      __glibcxx_requires_irreflexive_pred(__first, __last, __comp);
+      __glibcxx_requires_heap_pred(__first, __last, __comp);
+
+      typedef __decltype(__comp) _Cmp;
+      __gnu_cxx::__ops::_Iter_comp_iter<_Cmp> __cmp(_GLIBCXX_MOVE(__comp));
+      std::__sort_heap(__first, __last, __cmp);
+    }
+
+#if __cplusplus >= 201103L
+  /**
+   *  @brief  Search the end of a heap.
+   *  @param  __first  Start of range.
+   *  @param  __last   End of range.
+   *  @return  An iterator pointing to the first element not in the heap.
+   *  @ingroup heap_algorithms
+   *
+   *  This operation returns the last iterator i in [__first, __last) for which
+   *  the range [__first, i) is a heap.
+  */
+  template<typename _RandomAccessIterator>
+    _GLIBCXX20_CONSTEXPR
+    inline _RandomAccessIterator
+    is_heap_until(_RandomAccessIterator __first, _RandomAccessIterator __last)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_RandomAccessIteratorConcept<
+	    _RandomAccessIterator>)
+      __glibcxx_function_requires(_LessThanComparableConcept<
+	    typename iterator_traits<_RandomAccessIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+      __glibcxx_requires_irreflexive(__first, __last);
+
+      __gnu_cxx::__ops::_Iter_less_iter __comp;
+      return __first + 
+	std::__is_heap_until(__first, std::distance(__first, __last), __comp);
+    }
+
+  /**
+   *  @brief  Search the end of a heap using comparison functor.
+   *  @param  __first  Start of range.
+   *  @param  __last   End of range.
+   *  @param  __comp   Comparison functor to use.
+   *  @return  An iterator pointing to the first element not in the heap.
+   *  @ingroup heap_algorithms
+   *
+   *  This operation returns the last iterator i in [__first, __last) for which
+   *  the range [__first, i) is a heap.  Comparisons are made using __comp.
+  */
+  template<typename _RandomAccessIterator, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    inline _RandomAccessIterator
+    is_heap_until(_RandomAccessIterator __first, _RandomAccessIterator __last,
+		  _Compare __comp)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_RandomAccessIteratorConcept<
+	    _RandomAccessIterator>)
+      __glibcxx_requires_valid_range(__first, __last);
+      __glibcxx_requires_irreflexive_pred(__first, __last, __comp);
+
+      typedef __decltype(__comp) _Cmp;
+      __gnu_cxx::__ops::_Iter_comp_iter<_Cmp> __cmp(_GLIBCXX_MOVE(__comp));
+      return __first
+	+ std::__is_heap_until(__first, std::distance(__first, __last), __cmp);
+    }
+
+  /**
+   *  @brief  Determines whether a range is a heap.
+   *  @param  __first  Start of range.
+   *  @param  __last   End of range.
+   *  @return  True if range is a heap, false otherwise.
+   *  @ingroup heap_algorithms
+  */
+  template<typename _RandomAccessIterator>
+    _GLIBCXX20_CONSTEXPR
+    inline bool
+    is_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
+    { return std::is_heap_until(__first, __last) == __last; }
+
+  /**
+   *  @brief  Determines whether a range is a heap using comparison functor.
+   *  @param  __first  Start of range.
+   *  @param  __last   End of range.
+   *  @param  __comp   Comparison functor to use.
+   *  @return  True if range is a heap, false otherwise.
+   *  @ingroup heap_algorithms
+  */
+  template<typename _RandomAccessIterator, typename _Compare>
+    _GLIBCXX20_CONSTEXPR
+    inline bool
+    is_heap(_RandomAccessIterator __first, _RandomAccessIterator __last,
+	    _Compare __comp)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_RandomAccessIteratorConcept<
+	    _RandomAccessIterator>)
+      __glibcxx_requires_valid_range(__first, __last);
+      __glibcxx_requires_irreflexive_pred(__first, __last, __comp);
+
+      const auto __dist = std::distance(__first, __last);
+      typedef __decltype(__comp) _Cmp;
+      __gnu_cxx::__ops::_Iter_comp_iter<_Cmp> __cmp(_GLIBCXX_MOVE(__comp));
+      return std::__is_heap_until(__first, __dist, __cmp) == __dist;
+    }
+#endif
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif /* _STL_HEAP_H */
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@@ -0,0 +1,2608 @@
+// Iterators -*- C++ -*-
+
+// Copyright (C) 2001-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/*
+ *
+ * Copyright (c) 1994
+ * Hewlett-Packard Company
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Hewlett-Packard Company makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ *
+ *
+ * Copyright (c) 1996-1998
+ * Silicon Graphics Computer Systems, Inc.
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Silicon Graphics makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ */
+
+/** @file bits/stl_iterator.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{iterator}
+ *
+ *  This file implements reverse_iterator, back_insert_iterator,
+ *  front_insert_iterator, insert_iterator, __normal_iterator, and their
+ *  supporting functions and overloaded operators.
+ */
+
+#ifndef _STL_ITERATOR_H
+#define _STL_ITERATOR_H 1
+
+#include <bits/cpp_type_traits.h>
+#include <bits/stl_iterator_base_types.h>
+#include <ext/type_traits.h>
+#include <bits/move.h>
+#include <bits/ptr_traits.h>
+
+#if __cplusplus >= 201103L
+# include <type_traits>
+#endif
+
+#if __cplusplus > 201703L
+# define __cpp_lib_array_constexpr 201811L
+# define __cpp_lib_constexpr_iterator 201811L
+#elif __cplusplus == 201703L
+# define __cpp_lib_array_constexpr 201803L
+#endif
+
+#if __cplusplus >= 202002L
+# include <compare>
+# include <new>
+# include <bits/exception_defines.h>
+# include <bits/iterator_concepts.h>
+# include <bits/stl_construct.h>
+#endif
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /**
+   * @addtogroup iterators
+   * @{
+   */
+
+#if __cpp_lib_concepts
+  namespace __detail
+  {
+    // Weaken iterator_category _Cat to _Limit if it is derived from that,
+    // otherwise use _Otherwise.
+    template<typename _Cat, typename _Limit, typename _Otherwise = _Cat>
+      using __clamp_iter_cat
+	= __conditional_t<derived_from<_Cat, _Limit>, _Limit, _Otherwise>;
+  }
+#endif
+
+// Ignore warnings about std::iterator.
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+
+  // 24.4.1 Reverse iterators
+  /**
+   *  Bidirectional and random access iterators have corresponding reverse
+   *  %iterator adaptors that iterate through the data structure in the
+   *  opposite direction.  They have the same signatures as the corresponding
+   *  iterators.  The fundamental relation between a reverse %iterator and its
+   *  corresponding %iterator @c i is established by the identity:
+   *  @code
+   *      &*(reverse_iterator(i)) == &*(i - 1)
+   *  @endcode
+   *
+   *  <em>This mapping is dictated by the fact that while there is always a
+   *  pointer past the end of an array, there might not be a valid pointer
+   *  before the beginning of an array.</em> [24.4.1]/1,2
+   *
+   *  Reverse iterators can be tricky and surprising at first.  Their
+   *  semantics make sense, however, and the trickiness is a side effect of
+   *  the requirement that the iterators must be safe.
+  */
+  template<typename _Iterator>
+    class reverse_iterator
+    : public iterator<typename iterator_traits<_Iterator>::iterator_category,
+		      typename iterator_traits<_Iterator>::value_type,
+		      typename iterator_traits<_Iterator>::difference_type,
+		      typename iterator_traits<_Iterator>::pointer,
+                      typename iterator_traits<_Iterator>::reference>
+    {
+      template<typename _Iter>
+	friend class reverse_iterator;
+
+#if __cpp_lib_concepts
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 3435. three_way_comparable_with<reverse_iterator<int*>, [...]>
+      template<typename _Iter>
+	static constexpr bool __convertible = !is_same_v<_Iter, _Iterator>
+	    && convertible_to<const _Iter&, _Iterator>;
+#endif
+
+    protected:
+      _Iterator current;
+
+      typedef iterator_traits<_Iterator>		__traits_type;
+
+    public:
+      typedef _Iterator					iterator_type;
+      typedef typename __traits_type::pointer		pointer;
+#if ! __cpp_lib_concepts
+      typedef typename __traits_type::difference_type	difference_type;
+      typedef typename __traits_type::reference		reference;
+#else
+      using iterator_concept
+	= __conditional_t<random_access_iterator<_Iterator>,
+			  random_access_iterator_tag,
+			  bidirectional_iterator_tag>;
+      using iterator_category
+	= __detail::__clamp_iter_cat<typename __traits_type::iterator_category,
+				     random_access_iterator_tag>;
+      using value_type = iter_value_t<_Iterator>;
+      using difference_type = iter_difference_t<_Iterator>;
+      using reference = iter_reference_t<_Iterator>;
+#endif
+
+      /**
+       *  The default constructor value-initializes member @p current.
+       *  If it is a pointer, that means it is zero-initialized.
+      */
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 235 No specification of default ctor for reverse_iterator
+      // 1012. reverse_iterator default ctor should value initialize
+      _GLIBCXX17_CONSTEXPR
+      reverse_iterator()
+      _GLIBCXX_NOEXCEPT_IF(noexcept(_Iterator()))
+      : current()
+      { }
+
+      /**
+       *  This %iterator will move in the opposite direction that @p x does.
+      */
+      explicit _GLIBCXX17_CONSTEXPR
+      reverse_iterator(iterator_type __x)
+      _GLIBCXX_NOEXCEPT_IF(noexcept(_Iterator(__x)))
+      : current(__x)
+      { }
+
+      /**
+       *  The copy constructor is normal.
+      */
+      _GLIBCXX17_CONSTEXPR
+      reverse_iterator(const reverse_iterator& __x)
+      _GLIBCXX_NOEXCEPT_IF(noexcept(_Iterator(__x.current)))
+      : current(__x.current)
+      { }
+
+#if __cplusplus >= 201103L
+      reverse_iterator& operator=(const reverse_iterator&) = default;
+#endif
+
+      /**
+       *  A %reverse_iterator across other types can be copied if the
+       *  underlying %iterator can be converted to the type of @c current.
+      */
+      template<typename _Iter>
+#if __cpp_lib_concepts
+	requires __convertible<_Iter>
+#endif
+	_GLIBCXX17_CONSTEXPR
+        reverse_iterator(const reverse_iterator<_Iter>& __x)
+	_GLIBCXX_NOEXCEPT_IF(noexcept(_Iterator(__x.current)))
+	: current(__x.current)
+	{ }
+
+#if __cplusplus >= 201103L
+      template<typename _Iter>
+#if __cpp_lib_concepts
+	requires __convertible<_Iter>
+	  && assignable_from<_Iterator&, const _Iter&>
+#endif
+	_GLIBCXX17_CONSTEXPR
+	reverse_iterator&
+	operator=(const reverse_iterator<_Iter>& __x)
+	_GLIBCXX_NOEXCEPT_IF(noexcept(current = __x.current))
+	{
+	  current = __x.current;
+	  return *this;
+	}
+#endif
+
+      /**
+       *  @return  @c current, the %iterator used for underlying work.
+      */
+      _GLIBCXX_NODISCARD
+      _GLIBCXX17_CONSTEXPR iterator_type
+      base() const
+      _GLIBCXX_NOEXCEPT_IF(noexcept(_Iterator(current)))
+      { return current; }
+
+      /**
+       *  @return  A reference to the value at @c --current
+       *
+       *  This requires that @c --current is dereferenceable.
+       *
+       *  @warning This implementation requires that for an iterator of the
+       *           underlying iterator type, @c x, a reference obtained by
+       *           @c *x remains valid after @c x has been modified or
+       *           destroyed. This is a bug: http://gcc.gnu.org/PR51823
+      */
+      _GLIBCXX_NODISCARD
+      _GLIBCXX17_CONSTEXPR reference
+      operator*() const
+      {
+	_Iterator __tmp = current;
+	return *--__tmp;
+      }
+
+      /**
+       *  @return  A pointer to the value at @c --current
+       *
+       *  This requires that @c --current is dereferenceable.
+      */
+      _GLIBCXX_NODISCARD
+      _GLIBCXX17_CONSTEXPR pointer
+      operator->() const
+#if __cplusplus > 201703L && __cpp_concepts >= 201907L
+      requires is_pointer_v<_Iterator>
+	|| requires(const _Iterator __i) { __i.operator->(); }
+#endif
+      {
+	// _GLIBCXX_RESOLVE_LIB_DEFECTS
+	// 1052. operator-> should also support smart pointers
+	_Iterator __tmp = current;
+	--__tmp;
+	return _S_to_pointer(__tmp);
+      }
+
+      /**
+       *  @return  @c *this
+       *
+       *  Decrements the underlying iterator.
+      */
+      _GLIBCXX17_CONSTEXPR reverse_iterator&
+      operator++()
+      {
+	--current;
+	return *this;
+      }
+
+      /**
+       *  @return  The original value of @c *this
+       *
+       *  Decrements the underlying iterator.
+      */
+      _GLIBCXX17_CONSTEXPR reverse_iterator
+      operator++(int)
+      {
+	reverse_iterator __tmp = *this;
+	--current;
+	return __tmp;
+      }
+
+      /**
+       *  @return  @c *this
+       *
+       *  Increments the underlying iterator.
+      */
+      _GLIBCXX17_CONSTEXPR reverse_iterator&
+      operator--()
+      {
+	++current;
+	return *this;
+      }
+
+      /**
+       *  @return  A reverse_iterator with the previous value of @c *this
+       *
+       *  Increments the underlying iterator.
+      */
+      _GLIBCXX17_CONSTEXPR reverse_iterator
+      operator--(int)
+      {
+	reverse_iterator __tmp = *this;
+	++current;
+	return __tmp;
+      }
+
+      /**
+       *  @return  A reverse_iterator that refers to @c current - @a __n
+       *
+       *  The underlying iterator must be a Random Access Iterator.
+      */
+      _GLIBCXX_NODISCARD
+      _GLIBCXX17_CONSTEXPR reverse_iterator
+      operator+(difference_type __n) const
+      { return reverse_iterator(current - __n); }
+
+      /**
+       *  @return  *this
+       *
+       *  Moves the underlying iterator backwards @a __n steps.
+       *  The underlying iterator must be a Random Access Iterator.
+      */
+      _GLIBCXX17_CONSTEXPR reverse_iterator&
+      operator+=(difference_type __n)
+      {
+	current -= __n;
+	return *this;
+      }
+
+      /**
+       *  @return  A reverse_iterator that refers to @c current - @a __n
+       *
+       *  The underlying iterator must be a Random Access Iterator.
+      */
+      _GLIBCXX_NODISCARD
+      _GLIBCXX17_CONSTEXPR reverse_iterator
+      operator-(difference_type __n) const
+      { return reverse_iterator(current + __n); }
+
+      /**
+       *  @return  *this
+       *
+       *  Moves the underlying iterator forwards @a __n steps.
+       *  The underlying iterator must be a Random Access Iterator.
+      */
+      _GLIBCXX17_CONSTEXPR reverse_iterator&
+      operator-=(difference_type __n)
+      {
+	current += __n;
+	return *this;
+      }
+
+      /**
+       *  @return  The value at @c current - @a __n - 1
+       *
+       *  The underlying iterator must be a Random Access Iterator.
+      */
+      _GLIBCXX_NODISCARD
+      _GLIBCXX17_CONSTEXPR reference
+      operator[](difference_type __n) const
+      { return *(*this + __n); }
+
+#if __cplusplus > 201703L && __cpp_lib_concepts
+      [[nodiscard]]
+      friend constexpr iter_rvalue_reference_t<_Iterator>
+      iter_move(const reverse_iterator& __i)
+      noexcept(is_nothrow_copy_constructible_v<_Iterator>
+	       && noexcept(ranges::iter_move(--std::declval<_Iterator&>())))
+      {
+	auto __tmp = __i.base();
+	return ranges::iter_move(--__tmp);
+      }
+
+      template<indirectly_swappable<_Iterator> _Iter2>
+	friend constexpr void
+	iter_swap(const reverse_iterator& __x,
+		  const reverse_iterator<_Iter2>& __y)
+	noexcept(is_nothrow_copy_constructible_v<_Iterator>
+		 && is_nothrow_copy_constructible_v<_Iter2>
+		 && noexcept(ranges::iter_swap(--std::declval<_Iterator&>(),
+					       --std::declval<_Iter2&>())))
+	{
+	  auto __xtmp = __x.base();
+	  auto __ytmp = __y.base();
+	  ranges::iter_swap(--__xtmp, --__ytmp);
+	}
+#endif
+
+    private:
+      template<typename _Tp>
+	static _GLIBCXX17_CONSTEXPR _Tp*
+	_S_to_pointer(_Tp* __p)
+        { return __p; }
+
+      template<typename _Tp>
+	static _GLIBCXX17_CONSTEXPR pointer
+	_S_to_pointer(_Tp __t)
+        { return __t.operator->(); }
+    };
+
+  ///@{
+  /**
+   *  @param  __x  A %reverse_iterator.
+   *  @param  __y  A %reverse_iterator.
+   *  @return  A simple bool.
+   *
+   *  Reverse iterators forward comparisons to their underlying base()
+   *  iterators.
+   *
+  */
+#if __cplusplus <= 201703L || ! defined __cpp_lib_concepts
+  template<typename _Iterator>
+    _GLIBCXX_NODISCARD
+    inline _GLIBCXX17_CONSTEXPR bool
+    operator==(const reverse_iterator<_Iterator>& __x,
+	       const reverse_iterator<_Iterator>& __y)
+    { return __x.base() == __y.base(); }
+
+  template<typename _Iterator>
+    _GLIBCXX_NODISCARD
+    inline _GLIBCXX17_CONSTEXPR bool
+    operator<(const reverse_iterator<_Iterator>& __x,
+	      const reverse_iterator<_Iterator>& __y)
+    { return __y.base() < __x.base(); }
+
+  template<typename _Iterator>
+    _GLIBCXX_NODISCARD
+    inline _GLIBCXX17_CONSTEXPR bool
+    operator!=(const reverse_iterator<_Iterator>& __x,
+	       const reverse_iterator<_Iterator>& __y)
+    { return !(__x == __y); }
+
+  template<typename _Iterator>
+    _GLIBCXX_NODISCARD
+    inline _GLIBCXX17_CONSTEXPR bool
+    operator>(const reverse_iterator<_Iterator>& __x,
+	      const reverse_iterator<_Iterator>& __y)
+    { return __y < __x; }
+
+  template<typename _Iterator>
+    _GLIBCXX_NODISCARD
+    inline _GLIBCXX17_CONSTEXPR bool
+    operator<=(const reverse_iterator<_Iterator>& __x,
+	       const reverse_iterator<_Iterator>& __y)
+    { return !(__y < __x); }
+
+  template<typename _Iterator>
+    _GLIBCXX_NODISCARD
+    inline _GLIBCXX17_CONSTEXPR bool
+    operator>=(const reverse_iterator<_Iterator>& __x,
+	       const reverse_iterator<_Iterator>& __y)
+    { return !(__x < __y); }
+
+  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+  // DR 280. Comparison of reverse_iterator to const reverse_iterator.
+
+  template<typename _IteratorL, typename _IteratorR>
+    _GLIBCXX_NODISCARD
+    inline _GLIBCXX17_CONSTEXPR bool
+    operator==(const reverse_iterator<_IteratorL>& __x,
+	       const reverse_iterator<_IteratorR>& __y)
+    { return __x.base() == __y.base(); }
+
+  template<typename _IteratorL, typename _IteratorR>
+    _GLIBCXX_NODISCARD
+    inline _GLIBCXX17_CONSTEXPR bool
+    operator<(const reverse_iterator<_IteratorL>& __x,
+	      const reverse_iterator<_IteratorR>& __y)
+    { return __x.base() > __y.base(); }
+
+  template<typename _IteratorL, typename _IteratorR>
+    _GLIBCXX_NODISCARD
+    inline _GLIBCXX17_CONSTEXPR bool
+    operator!=(const reverse_iterator<_IteratorL>& __x,
+	       const reverse_iterator<_IteratorR>& __y)
+    { return __x.base() != __y.base(); }
+
+  template<typename _IteratorL, typename _IteratorR>
+    _GLIBCXX_NODISCARD
+    inline _GLIBCXX17_CONSTEXPR bool
+    operator>(const reverse_iterator<_IteratorL>& __x,
+	      const reverse_iterator<_IteratorR>& __y)
+    { return __x.base() < __y.base(); }
+
+  template<typename _IteratorL, typename _IteratorR>
+    inline _GLIBCXX17_CONSTEXPR bool
+    operator<=(const reverse_iterator<_IteratorL>& __x,
+	       const reverse_iterator<_IteratorR>& __y)
+    { return __x.base() >= __y.base(); }
+
+  template<typename _IteratorL, typename _IteratorR>
+    _GLIBCXX_NODISCARD
+    inline _GLIBCXX17_CONSTEXPR bool
+    operator>=(const reverse_iterator<_IteratorL>& __x,
+	       const reverse_iterator<_IteratorR>& __y)
+    { return __x.base() <= __y.base(); }
+#else // C++20
+  template<typename _IteratorL, typename _IteratorR>
+    [[nodiscard]]
+    constexpr bool
+    operator==(const reverse_iterator<_IteratorL>& __x,
+	       const reverse_iterator<_IteratorR>& __y)
+    requires requires { { __x.base() == __y.base() } -> convertible_to<bool>; }
+    { return __x.base() == __y.base(); }
+
+  template<typename _IteratorL, typename _IteratorR>
+    [[nodiscard]]
+    constexpr bool
+    operator!=(const reverse_iterator<_IteratorL>& __x,
+	       const reverse_iterator<_IteratorR>& __y)
+    requires requires { { __x.base() != __y.base() } -> convertible_to<bool>; }
+    { return __x.base() != __y.base(); }
+
+  template<typename _IteratorL, typename _IteratorR>
+    [[nodiscard]]
+    constexpr bool
+    operator<(const reverse_iterator<_IteratorL>& __x,
+	      const reverse_iterator<_IteratorR>& __y)
+    requires requires { { __x.base() > __y.base() } -> convertible_to<bool>; }
+    { return __x.base() > __y.base(); }
+
+  template<typename _IteratorL, typename _IteratorR>
+    [[nodiscard]]
+    constexpr bool
+    operator>(const reverse_iterator<_IteratorL>& __x,
+	      const reverse_iterator<_IteratorR>& __y)
+    requires requires { { __x.base() < __y.base() } -> convertible_to<bool>; }
+    { return __x.base() < __y.base(); }
+
+  template<typename _IteratorL, typename _IteratorR>
+    [[nodiscard]]
+    constexpr bool
+    operator<=(const reverse_iterator<_IteratorL>& __x,
+	       const reverse_iterator<_IteratorR>& __y)
+    requires requires { { __x.base() >= __y.base() } -> convertible_to<bool>; }
+    { return __x.base() >= __y.base(); }
+
+  template<typename _IteratorL, typename _IteratorR>
+    [[nodiscard]]
+    constexpr bool
+    operator>=(const reverse_iterator<_IteratorL>& __x,
+	       const reverse_iterator<_IteratorR>& __y)
+    requires requires { { __x.base() <= __y.base() } -> convertible_to<bool>; }
+    { return __x.base() <= __y.base(); }
+
+  template<typename _IteratorL,
+	   three_way_comparable_with<_IteratorL> _IteratorR>
+    [[nodiscard]]
+    constexpr compare_three_way_result_t<_IteratorL, _IteratorR>
+    operator<=>(const reverse_iterator<_IteratorL>& __x,
+		const reverse_iterator<_IteratorR>& __y)
+    { return __y.base() <=> __x.base(); }
+
+  // Additional, non-standard overloads to avoid ambiguities with greedy,
+  // unconstrained overloads in associated namespaces.
+
+  template<typename _Iterator>
+    [[nodiscard]]
+    constexpr bool
+    operator==(const reverse_iterator<_Iterator>& __x,
+	       const reverse_iterator<_Iterator>& __y)
+    requires requires { { __x.base() == __y.base() } -> convertible_to<bool>; }
+    { return __x.base() == __y.base(); }
+
+  template<three_way_comparable _Iterator>
+    [[nodiscard]]
+    constexpr compare_three_way_result_t<_Iterator, _Iterator>
+    operator<=>(const reverse_iterator<_Iterator>& __x,
+		const reverse_iterator<_Iterator>& __y)
+    { return __y.base() <=> __x.base(); }
+#endif // C++20
+  ///@}
+
+#if __cplusplus < 201103L
+  template<typename _Iterator>
+    inline typename reverse_iterator<_Iterator>::difference_type
+    operator-(const reverse_iterator<_Iterator>& __x,
+	      const reverse_iterator<_Iterator>& __y)
+    { return __y.base() - __x.base(); }
+
+  template<typename _IteratorL, typename _IteratorR>
+    inline typename reverse_iterator<_IteratorL>::difference_type
+    operator-(const reverse_iterator<_IteratorL>& __x,
+	      const reverse_iterator<_IteratorR>& __y)
+    { return __y.base() - __x.base(); }
+#else
+  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+  // DR 685. reverse_iterator/move_iterator difference has invalid signatures
+  template<typename _IteratorL, typename _IteratorR>
+    [[__nodiscard__]]
+    inline _GLIBCXX17_CONSTEXPR auto
+    operator-(const reverse_iterator<_IteratorL>& __x,
+	      const reverse_iterator<_IteratorR>& __y)
+    -> decltype(__y.base() - __x.base())
+    { return __y.base() - __x.base(); }
+#endif
+
+  template<typename _Iterator>
+    _GLIBCXX_NODISCARD
+    inline _GLIBCXX17_CONSTEXPR reverse_iterator<_Iterator>
+    operator+(typename reverse_iterator<_Iterator>::difference_type __n,
+	      const reverse_iterator<_Iterator>& __x)
+    { return reverse_iterator<_Iterator>(__x.base() - __n); }
+
+#if __cplusplus >= 201103L
+  // Same as C++14 make_reverse_iterator but used in C++11 mode too.
+  template<typename _Iterator>
+    inline _GLIBCXX17_CONSTEXPR reverse_iterator<_Iterator>
+    __make_reverse_iterator(_Iterator __i)
+    { return reverse_iterator<_Iterator>(__i); }
+
+# if __cplusplus >= 201402L
+#  define __cpp_lib_make_reverse_iterator 201402L
+
+  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+  // DR 2285. make_reverse_iterator
+  /// Generator function for reverse_iterator.
+  template<typename _Iterator>
+    [[__nodiscard__]]
+    inline _GLIBCXX17_CONSTEXPR reverse_iterator<_Iterator>
+    make_reverse_iterator(_Iterator __i)
+    { return reverse_iterator<_Iterator>(__i); }
+
+#  if __cplusplus > 201703L && defined __cpp_lib_concepts
+  template<typename _Iterator1, typename _Iterator2>
+    requires (!sized_sentinel_for<_Iterator1, _Iterator2>)
+    inline constexpr bool
+    disable_sized_sentinel_for<reverse_iterator<_Iterator1>,
+			       reverse_iterator<_Iterator2>> = true;
+#  endif // C++20
+# endif // C++14
+
+  template<typename _Iterator>
+    _GLIBCXX20_CONSTEXPR
+    auto
+    __niter_base(reverse_iterator<_Iterator> __it)
+    -> decltype(__make_reverse_iterator(__niter_base(__it.base())))
+    { return __make_reverse_iterator(__niter_base(__it.base())); }
+
+  template<typename _Iterator>
+    struct __is_move_iterator<reverse_iterator<_Iterator> >
+      : __is_move_iterator<_Iterator>
+    { };
+
+  template<typename _Iterator>
+    _GLIBCXX20_CONSTEXPR
+    auto
+    __miter_base(reverse_iterator<_Iterator> __it)
+    -> decltype(__make_reverse_iterator(__miter_base(__it.base())))
+    { return __make_reverse_iterator(__miter_base(__it.base())); }
+#endif // C++11
+
+  // 24.4.2.2.1 back_insert_iterator
+  /**
+   *  @brief  Turns assignment into insertion.
+   *
+   *  These are output iterators, constructed from a container-of-T.
+   *  Assigning a T to the iterator appends it to the container using
+   *  push_back.
+   *
+   *  Tip:  Using the back_inserter function to create these iterators can
+   *  save typing.
+  */
+  template<typename _Container>
+    class back_insert_iterator
+    : public iterator<output_iterator_tag, void, void, void, void>
+    {
+    protected:
+      _Container* container;
+
+    public:
+      /// A nested typedef for the type of whatever container you used.
+      typedef _Container          container_type;
+#if __cplusplus > 201703L
+      using difference_type = ptrdiff_t;
+#endif
+
+      /// The only way to create this %iterator is with a container.
+      explicit _GLIBCXX20_CONSTEXPR
+      back_insert_iterator(_Container& __x)
+      : container(std::__addressof(__x)) { }
+
+      /**
+       *  @param  __value  An instance of whatever type
+       *                 container_type::const_reference is; presumably a
+       *                 reference-to-const T for container<T>.
+       *  @return  This %iterator, for chained operations.
+       *
+       *  This kind of %iterator doesn't really have a @a position in the
+       *  container (you can think of the position as being permanently at
+       *  the end, if you like).  Assigning a value to the %iterator will
+       *  always append the value to the end of the container.
+      */
+#if __cplusplus < 201103L
+      back_insert_iterator&
+      operator=(typename _Container::const_reference __value)
+      {
+	container->push_back(__value);
+	return *this;
+      }
+#else
+      _GLIBCXX20_CONSTEXPR
+      back_insert_iterator&
+      operator=(const typename _Container::value_type& __value)
+      {
+	container->push_back(__value);
+	return *this;
+      }
+
+      _GLIBCXX20_CONSTEXPR
+      back_insert_iterator&
+      operator=(typename _Container::value_type&& __value)
+      {
+	container->push_back(std::move(__value));
+	return *this;
+      }
+#endif
+
+      /// Simply returns *this.
+      _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
+      back_insert_iterator&
+      operator*()
+      { return *this; }
+
+      /// Simply returns *this.  (This %iterator does not @a move.)
+      _GLIBCXX20_CONSTEXPR
+      back_insert_iterator&
+      operator++()
+      { return *this; }
+
+      /// Simply returns *this.  (This %iterator does not @a move.)
+      _GLIBCXX20_CONSTEXPR
+      back_insert_iterator
+      operator++(int)
+      { return *this; }
+    };
+
+  /**
+   *  @param  __x  A container of arbitrary type.
+   *  @return  An instance of back_insert_iterator working on @p __x.
+   *
+   *  This wrapper function helps in creating back_insert_iterator instances.
+   *  Typing the name of the %iterator requires knowing the precise full
+   *  type of the container, which can be tedious and impedes generic
+   *  programming.  Using this function lets you take advantage of automatic
+   *  template parameter deduction, making the compiler match the correct
+   *  types for you.
+  */
+  template<typename _Container>
+    _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
+    inline back_insert_iterator<_Container>
+    back_inserter(_Container& __x)
+    { return back_insert_iterator<_Container>(__x); }
+
+  /**
+   *  @brief  Turns assignment into insertion.
+   *
+   *  These are output iterators, constructed from a container-of-T.
+   *  Assigning a T to the iterator prepends it to the container using
+   *  push_front.
+   *
+   *  Tip:  Using the front_inserter function to create these iterators can
+   *  save typing.
+  */
+  template<typename _Container>
+    class front_insert_iterator
+    : public iterator<output_iterator_tag, void, void, void, void>
+    {
+    protected:
+      _Container* container;
+
+    public:
+      /// A nested typedef for the type of whatever container you used.
+      typedef _Container          container_type;
+#if __cplusplus > 201703L
+      using difference_type = ptrdiff_t;
+#endif
+
+      /// The only way to create this %iterator is with a container.
+      explicit _GLIBCXX20_CONSTEXPR
+      front_insert_iterator(_Container& __x)
+      : container(std::__addressof(__x)) { }
+
+      /**
+       *  @param  __value  An instance of whatever type
+       *                 container_type::const_reference is; presumably a
+       *                 reference-to-const T for container<T>.
+       *  @return  This %iterator, for chained operations.
+       *
+       *  This kind of %iterator doesn't really have a @a position in the
+       *  container (you can think of the position as being permanently at
+       *  the front, if you like).  Assigning a value to the %iterator will
+       *  always prepend the value to the front of the container.
+      */
+#if __cplusplus < 201103L
+      front_insert_iterator&
+      operator=(typename _Container::const_reference __value)
+      {
+	container->push_front(__value);
+	return *this;
+      }
+#else
+      _GLIBCXX20_CONSTEXPR
+      front_insert_iterator&
+      operator=(const typename _Container::value_type& __value)
+      {
+	container->push_front(__value);
+	return *this;
+      }
+
+      _GLIBCXX20_CONSTEXPR
+      front_insert_iterator&
+      operator=(typename _Container::value_type&& __value)
+      {
+	container->push_front(std::move(__value));
+	return *this;
+      }
+#endif
+
+      /// Simply returns *this.
+      _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
+      front_insert_iterator&
+      operator*()
+      { return *this; }
+
+      /// Simply returns *this.  (This %iterator does not @a move.)
+      _GLIBCXX20_CONSTEXPR
+      front_insert_iterator&
+      operator++()
+      { return *this; }
+
+      /// Simply returns *this.  (This %iterator does not @a move.)
+      _GLIBCXX20_CONSTEXPR
+      front_insert_iterator
+      operator++(int)
+      { return *this; }
+    };
+
+  /**
+   *  @param  __x  A container of arbitrary type.
+   *  @return  An instance of front_insert_iterator working on @p x.
+   *
+   *  This wrapper function helps in creating front_insert_iterator instances.
+   *  Typing the name of the %iterator requires knowing the precise full
+   *  type of the container, which can be tedious and impedes generic
+   *  programming.  Using this function lets you take advantage of automatic
+   *  template parameter deduction, making the compiler match the correct
+   *  types for you.
+  */
+  template<typename _Container>
+    _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
+    inline front_insert_iterator<_Container>
+    front_inserter(_Container& __x)
+    { return front_insert_iterator<_Container>(__x); }
+
+  /**
+   *  @brief  Turns assignment into insertion.
+   *
+   *  These are output iterators, constructed from a container-of-T.
+   *  Assigning a T to the iterator inserts it in the container at the
+   *  %iterator's position, rather than overwriting the value at that
+   *  position.
+   *
+   *  (Sequences will actually insert a @e copy of the value before the
+   *  %iterator's position.)
+   *
+   *  Tip:  Using the inserter function to create these iterators can
+   *  save typing.
+  */
+  template<typename _Container>
+    class insert_iterator
+    : public iterator<output_iterator_tag, void, void, void, void>
+    {
+#if __cplusplus > 201703L && defined __cpp_lib_concepts
+      using _Iter = std::__detail::__range_iter_t<_Container>;
+#else
+      typedef typename _Container::iterator		_Iter;
+#endif
+    protected:
+      _Container* container;
+      _Iter iter;
+
+    public:
+      /// A nested typedef for the type of whatever container you used.
+      typedef _Container          container_type;
+
+#if __cplusplus > 201703L && defined __cpp_lib_concepts
+      using difference_type = ptrdiff_t;
+#endif
+
+      /**
+       *  The only way to create this %iterator is with a container and an
+       *  initial position (a normal %iterator into the container).
+      */
+      _GLIBCXX20_CONSTEXPR
+      insert_iterator(_Container& __x, _Iter __i)
+      : container(std::__addressof(__x)), iter(__i) {}
+
+      /**
+       *  @param  __value  An instance of whatever type
+       *                 container_type::const_reference is; presumably a
+       *                 reference-to-const T for container<T>.
+       *  @return  This %iterator, for chained operations.
+       *
+       *  This kind of %iterator maintains its own position in the
+       *  container.  Assigning a value to the %iterator will insert the
+       *  value into the container at the place before the %iterator.
+       *
+       *  The position is maintained such that subsequent assignments will
+       *  insert values immediately after one another.  For example,
+       *  @code
+       *     // vector v contains A and Z
+       *
+       *     insert_iterator i (v, ++v.begin());
+       *     i = 1;
+       *     i = 2;
+       *     i = 3;
+       *
+       *     // vector v contains A, 1, 2, 3, and Z
+       *  @endcode
+      */
+#if __cplusplus < 201103L
+      insert_iterator&
+      operator=(typename _Container::const_reference __value)
+      {
+	iter = container->insert(iter, __value);
+	++iter;
+	return *this;
+      }
+#else
+      _GLIBCXX20_CONSTEXPR
+      insert_iterator&
+      operator=(const typename _Container::value_type& __value)
+      {
+	iter = container->insert(iter, __value);
+	++iter;
+	return *this;
+      }
+
+      _GLIBCXX20_CONSTEXPR
+      insert_iterator&
+      operator=(typename _Container::value_type&& __value)
+      {
+	iter = container->insert(iter, std::move(__value));
+	++iter;
+	return *this;
+      }
+#endif
+
+      /// Simply returns *this.
+      _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
+      insert_iterator&
+      operator*()
+      { return *this; }
+
+      /// Simply returns *this.  (This %iterator does not @a move.)
+      _GLIBCXX20_CONSTEXPR
+      insert_iterator&
+      operator++()
+      { return *this; }
+
+      /// Simply returns *this.  (This %iterator does not @a move.)
+      _GLIBCXX20_CONSTEXPR
+      insert_iterator&
+      operator++(int)
+      { return *this; }
+    };
+
+#pragma GCC diagnostic pop
+
+  /**
+   *  @param __x  A container of arbitrary type.
+   *  @param __i  An iterator into the container.
+   *  @return  An instance of insert_iterator working on @p __x.
+   *
+   *  This wrapper function helps in creating insert_iterator instances.
+   *  Typing the name of the %iterator requires knowing the precise full
+   *  type of the container, which can be tedious and impedes generic
+   *  programming.  Using this function lets you take advantage of automatic
+   *  template parameter deduction, making the compiler match the correct
+   *  types for you.
+  */
+#if __cplusplus > 201703L && defined __cpp_lib_concepts
+  template<typename _Container>
+    [[nodiscard]]
+    constexpr insert_iterator<_Container>
+    inserter(_Container& __x, std::__detail::__range_iter_t<_Container> __i)
+    { return insert_iterator<_Container>(__x, __i); }
+#else
+  template<typename _Container>
+    _GLIBCXX_NODISCARD
+    inline insert_iterator<_Container>
+    inserter(_Container& __x, typename _Container::iterator __i)
+    { return insert_iterator<_Container>(__x, __i); }
+#endif
+
+  /// @} group iterators
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  // This iterator adapter is @a normal in the sense that it does not
+  // change the semantics of any of the operators of its iterator
+  // parameter.  Its primary purpose is to convert an iterator that is
+  // not a class, e.g. a pointer, into an iterator that is a class.
+  // The _Container parameter exists solely so that different containers
+  // using this template can instantiate different types, even if the
+  // _Iterator parameter is the same.
+  template<typename _Iterator, typename _Container>
+    class __normal_iterator
+    {
+    protected:
+      _Iterator _M_current;
+
+      typedef std::iterator_traits<_Iterator>		__traits_type;
+
+#if __cplusplus >= 201103L
+      template<typename _Iter>
+	using __convertible_from
+	  = std::__enable_if_t<std::is_convertible<_Iter, _Iterator>::value>;
+#endif
+
+    public:
+      typedef _Iterator					iterator_type;
+      typedef typename __traits_type::iterator_category iterator_category;
+      typedef typename __traits_type::value_type  	value_type;
+      typedef typename __traits_type::difference_type 	difference_type;
+      typedef typename __traits_type::reference 	reference;
+      typedef typename __traits_type::pointer   	pointer;
+
+#if __cplusplus > 201703L && __cpp_lib_concepts
+      using iterator_concept = std::__detail::__iter_concept<_Iterator>;
+#endif
+
+      _GLIBCXX_CONSTEXPR __normal_iterator() _GLIBCXX_NOEXCEPT
+      : _M_current(_Iterator()) { }
+
+      explicit _GLIBCXX20_CONSTEXPR
+      __normal_iterator(const _Iterator& __i) _GLIBCXX_NOEXCEPT
+      : _M_current(__i) { }
+
+      // Allow iterator to const_iterator conversion
+#if __cplusplus >= 201103L
+      template<typename _Iter, typename = __convertible_from<_Iter>>
+	_GLIBCXX20_CONSTEXPR
+	__normal_iterator(const __normal_iterator<_Iter, _Container>& __i)
+	noexcept
+#else
+      // N.B. _Container::pointer is not actually in container requirements,
+      // but is present in std::vector and std::basic_string.
+      template<typename _Iter>
+        __normal_iterator(const __normal_iterator<_Iter,
+			  typename __enable_if<
+	       (std::__are_same<_Iter, typename _Container::pointer>::__value),
+		      _Container>::__type>& __i)
+#endif
+        : _M_current(__i.base()) { }
+
+      // Forward iterator requirements
+      _GLIBCXX20_CONSTEXPR
+      reference
+      operator*() const _GLIBCXX_NOEXCEPT
+      { return *_M_current; }
+
+      _GLIBCXX20_CONSTEXPR
+      pointer
+      operator->() const _GLIBCXX_NOEXCEPT
+      { return _M_current; }
+
+      _GLIBCXX20_CONSTEXPR
+      __normal_iterator&
+      operator++() _GLIBCXX_NOEXCEPT
+      {
+	++_M_current;
+	return *this;
+      }
+
+      _GLIBCXX20_CONSTEXPR
+      __normal_iterator
+      operator++(int) _GLIBCXX_NOEXCEPT
+      { return __normal_iterator(_M_current++); }
+
+      // Bidirectional iterator requirements
+      _GLIBCXX20_CONSTEXPR
+      __normal_iterator&
+      operator--() _GLIBCXX_NOEXCEPT
+      {
+	--_M_current;
+	return *this;
+      }
+
+      _GLIBCXX20_CONSTEXPR
+      __normal_iterator
+      operator--(int) _GLIBCXX_NOEXCEPT
+      { return __normal_iterator(_M_current--); }
+
+      // Random access iterator requirements
+      _GLIBCXX20_CONSTEXPR
+      reference
+      operator[](difference_type __n) const _GLIBCXX_NOEXCEPT
+      { return _M_current[__n]; }
+
+      _GLIBCXX20_CONSTEXPR
+      __normal_iterator&
+      operator+=(difference_type __n) _GLIBCXX_NOEXCEPT
+      { _M_current += __n; return *this; }
+
+      _GLIBCXX20_CONSTEXPR
+      __normal_iterator
+      operator+(difference_type __n) const _GLIBCXX_NOEXCEPT
+      { return __normal_iterator(_M_current + __n); }
+
+      _GLIBCXX20_CONSTEXPR
+      __normal_iterator&
+      operator-=(difference_type __n) _GLIBCXX_NOEXCEPT
+      { _M_current -= __n; return *this; }
+
+      _GLIBCXX20_CONSTEXPR
+      __normal_iterator
+      operator-(difference_type __n) const _GLIBCXX_NOEXCEPT
+      { return __normal_iterator(_M_current - __n); }
+
+      _GLIBCXX20_CONSTEXPR
+      const _Iterator&
+      base() const _GLIBCXX_NOEXCEPT
+      { return _M_current; }
+    };
+
+  // Note: In what follows, the left- and right-hand-side iterators are
+  // allowed to vary in types (conceptually in cv-qualification) so that
+  // comparison between cv-qualified and non-cv-qualified iterators be
+  // valid.  However, the greedy and unfriendly operators in std::rel_ops
+  // will make overload resolution ambiguous (when in scope) if we don't
+  // provide overloads whose operands are of the same type.  Can someone
+  // remind me what generic programming is about? -- Gaby
+
+#if __cpp_lib_three_way_comparison
+  template<typename _IteratorL, typename _IteratorR, typename _Container>
+    [[nodiscard]]
+    constexpr bool
+    operator==(const __normal_iterator<_IteratorL, _Container>& __lhs,
+	       const __normal_iterator<_IteratorR, _Container>& __rhs)
+    noexcept(noexcept(__lhs.base() == __rhs.base()))
+    requires requires {
+      { __lhs.base() == __rhs.base() } -> std::convertible_to<bool>;
+    }
+    { return __lhs.base() == __rhs.base(); }
+
+  template<typename _IteratorL, typename _IteratorR, typename _Container>
+    [[nodiscard]]
+    constexpr std::__detail::__synth3way_t<_IteratorR, _IteratorL>
+    operator<=>(const __normal_iterator<_IteratorL, _Container>& __lhs,
+		const __normal_iterator<_IteratorR, _Container>& __rhs)
+    noexcept(noexcept(std::__detail::__synth3way(__lhs.base(), __rhs.base())))
+    { return std::__detail::__synth3way(__lhs.base(), __rhs.base()); }
+
+  template<typename _Iterator, typename _Container>
+    [[nodiscard]]
+    constexpr bool
+    operator==(const __normal_iterator<_Iterator, _Container>& __lhs,
+	       const __normal_iterator<_Iterator, _Container>& __rhs)
+    noexcept(noexcept(__lhs.base() == __rhs.base()))
+    requires requires {
+      { __lhs.base() == __rhs.base() } -> std::convertible_to<bool>;
+    }
+    { return __lhs.base() == __rhs.base(); }
+
+  template<typename _Iterator, typename _Container>
+    [[nodiscard]]
+    constexpr std::__detail::__synth3way_t<_Iterator>
+    operator<=>(const __normal_iterator<_Iterator, _Container>& __lhs,
+		const __normal_iterator<_Iterator, _Container>& __rhs)
+    noexcept(noexcept(std::__detail::__synth3way(__lhs.base(), __rhs.base())))
+    { return std::__detail::__synth3way(__lhs.base(), __rhs.base()); }
+#else
+   // Forward iterator requirements
+  template<typename _IteratorL, typename _IteratorR, typename _Container>
+    _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
+    inline bool
+    operator==(const __normal_iterator<_IteratorL, _Container>& __lhs,
+	       const __normal_iterator<_IteratorR, _Container>& __rhs)
+    _GLIBCXX_NOEXCEPT
+    { return __lhs.base() == __rhs.base(); }
+
+  template<typename _Iterator, typename _Container>
+    _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
+    inline bool
+    operator==(const __normal_iterator<_Iterator, _Container>& __lhs,
+	       const __normal_iterator<_Iterator, _Container>& __rhs)
+    _GLIBCXX_NOEXCEPT
+    { return __lhs.base() == __rhs.base(); }
+
+  template<typename _IteratorL, typename _IteratorR, typename _Container>
+    _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
+    inline bool
+    operator!=(const __normal_iterator<_IteratorL, _Container>& __lhs,
+	       const __normal_iterator<_IteratorR, _Container>& __rhs)
+    _GLIBCXX_NOEXCEPT
+    { return __lhs.base() != __rhs.base(); }
+
+  template<typename _Iterator, typename _Container>
+    _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
+    inline bool
+    operator!=(const __normal_iterator<_Iterator, _Container>& __lhs,
+	       const __normal_iterator<_Iterator, _Container>& __rhs)
+    _GLIBCXX_NOEXCEPT
+    { return __lhs.base() != __rhs.base(); }
+
+  // Random access iterator requirements
+  template<typename _IteratorL, typename _IteratorR, typename _Container>
+    _GLIBCXX_NODISCARD
+    inline bool
+    operator<(const __normal_iterator<_IteratorL, _Container>& __lhs,
+	      const __normal_iterator<_IteratorR, _Container>& __rhs)
+    _GLIBCXX_NOEXCEPT
+    { return __lhs.base() < __rhs.base(); }
+
+  template<typename _Iterator, typename _Container>
+    _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
+    inline bool
+    operator<(const __normal_iterator<_Iterator, _Container>& __lhs,
+	      const __normal_iterator<_Iterator, _Container>& __rhs)
+    _GLIBCXX_NOEXCEPT
+    { return __lhs.base() < __rhs.base(); }
+
+  template<typename _IteratorL, typename _IteratorR, typename _Container>
+    _GLIBCXX_NODISCARD
+    inline bool
+    operator>(const __normal_iterator<_IteratorL, _Container>& __lhs,
+	      const __normal_iterator<_IteratorR, _Container>& __rhs)
+    _GLIBCXX_NOEXCEPT
+    { return __lhs.base() > __rhs.base(); }
+
+  template<typename _Iterator, typename _Container>
+    _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
+    inline bool
+    operator>(const __normal_iterator<_Iterator, _Container>& __lhs,
+	      const __normal_iterator<_Iterator, _Container>& __rhs)
+    _GLIBCXX_NOEXCEPT
+    { return __lhs.base() > __rhs.base(); }
+
+  template<typename _IteratorL, typename _IteratorR, typename _Container>
+    _GLIBCXX_NODISCARD
+    inline bool
+    operator<=(const __normal_iterator<_IteratorL, _Container>& __lhs,
+	       const __normal_iterator<_IteratorR, _Container>& __rhs)
+    _GLIBCXX_NOEXCEPT
+    { return __lhs.base() <= __rhs.base(); }
+
+  template<typename _Iterator, typename _Container>
+    _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
+    inline bool
+    operator<=(const __normal_iterator<_Iterator, _Container>& __lhs,
+	       const __normal_iterator<_Iterator, _Container>& __rhs)
+    _GLIBCXX_NOEXCEPT
+    { return __lhs.base() <= __rhs.base(); }
+
+  template<typename _IteratorL, typename _IteratorR, typename _Container>
+    _GLIBCXX_NODISCARD
+    inline bool
+    operator>=(const __normal_iterator<_IteratorL, _Container>& __lhs,
+	       const __normal_iterator<_IteratorR, _Container>& __rhs)
+    _GLIBCXX_NOEXCEPT
+    { return __lhs.base() >= __rhs.base(); }
+
+  template<typename _Iterator, typename _Container>
+    _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
+    inline bool
+    operator>=(const __normal_iterator<_Iterator, _Container>& __lhs,
+	       const __normal_iterator<_Iterator, _Container>& __rhs)
+    _GLIBCXX_NOEXCEPT
+    { return __lhs.base() >= __rhs.base(); }
+#endif // three-way comparison
+
+  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+  // According to the resolution of DR179 not only the various comparison
+  // operators but also operator- must accept mixed iterator/const_iterator
+  // parameters.
+  template<typename _IteratorL, typename _IteratorR, typename _Container>
+#if __cplusplus >= 201103L
+    // DR 685.
+    [[__nodiscard__]] _GLIBCXX20_CONSTEXPR
+    inline auto
+    operator-(const __normal_iterator<_IteratorL, _Container>& __lhs,
+	      const __normal_iterator<_IteratorR, _Container>& __rhs) noexcept
+    -> decltype(__lhs.base() - __rhs.base())
+#else
+    inline typename __normal_iterator<_IteratorL, _Container>::difference_type
+    operator-(const __normal_iterator<_IteratorL, _Container>& __lhs,
+	      const __normal_iterator<_IteratorR, _Container>& __rhs)
+#endif
+    { return __lhs.base() - __rhs.base(); }
+
+  template<typename _Iterator, typename _Container>
+    _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
+    inline typename __normal_iterator<_Iterator, _Container>::difference_type
+    operator-(const __normal_iterator<_Iterator, _Container>& __lhs,
+	      const __normal_iterator<_Iterator, _Container>& __rhs)
+    _GLIBCXX_NOEXCEPT
+    { return __lhs.base() - __rhs.base(); }
+
+  template<typename _Iterator, typename _Container>
+    _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
+    inline __normal_iterator<_Iterator, _Container>
+    operator+(typename __normal_iterator<_Iterator, _Container>::difference_type
+	      __n, const __normal_iterator<_Iterator, _Container>& __i)
+    _GLIBCXX_NOEXCEPT
+    { return __normal_iterator<_Iterator, _Container>(__i.base() + __n); }
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  template<typename _Iterator, typename _Container>
+    _GLIBCXX20_CONSTEXPR
+    _Iterator
+    __niter_base(__gnu_cxx::__normal_iterator<_Iterator, _Container> __it)
+    _GLIBCXX_NOEXCEPT_IF(std::is_nothrow_copy_constructible<_Iterator>::value)
+    { return __it.base(); }
+
+#if __cplusplus >= 201103L
+
+#if __cplusplus <= 201703L
+  // Need to overload __to_address because the pointer_traits primary template
+  // will deduce element_type of __normal_iterator<T*, C> as T* rather than T.
+  template<typename _Iterator, typename _Container>
+    constexpr auto
+    __to_address(const __gnu_cxx::__normal_iterator<_Iterator,
+						    _Container>& __it) noexcept
+    -> decltype(std::__to_address(__it.base()))
+    { return std::__to_address(__it.base()); }
+#endif
+
+  /**
+   * @addtogroup iterators
+   * @{
+   */
+
+#if __cplusplus > 201703L && __cpp_lib_concepts
+  template<semiregular _Sent>
+    class move_sentinel
+    {
+    public:
+      constexpr
+      move_sentinel()
+      noexcept(is_nothrow_default_constructible_v<_Sent>)
+      : _M_last() { }
+
+      constexpr explicit
+      move_sentinel(_Sent __s)
+      noexcept(is_nothrow_move_constructible_v<_Sent>)
+      : _M_last(std::move(__s)) { }
+
+      template<typename _S2> requires convertible_to<const _S2&, _Sent>
+	constexpr
+	move_sentinel(const move_sentinel<_S2>& __s)
+	noexcept(is_nothrow_constructible_v<_Sent, const _S2&>)
+	: _M_last(__s.base())
+	{ }
+
+      template<typename _S2> requires assignable_from<_Sent&, const _S2&>
+	constexpr move_sentinel&
+	operator=(const move_sentinel<_S2>& __s)
+	noexcept(is_nothrow_assignable_v<_Sent, const _S2&>)
+	{
+	  _M_last = __s.base();
+	  return *this;
+	}
+
+      [[nodiscard]]
+      constexpr _Sent
+      base() const
+      noexcept(is_nothrow_copy_constructible_v<_Sent>)
+      { return _M_last; }
+
+    private:
+      _Sent _M_last;
+    };
+#endif // C++20
+
+  namespace __detail
+  {
+#if __cplusplus > 201703L && __cpp_lib_concepts
+    template<typename _Iterator>
+      struct __move_iter_cat
+      { };
+
+    template<typename _Iterator>
+      requires requires { typename iterator_traits<_Iterator>::iterator_category; }
+      struct __move_iter_cat<_Iterator>
+      {
+	using iterator_category
+	  = __clamp_iter_cat<typename iterator_traits<_Iterator>::iterator_category,
+			     random_access_iterator_tag>;
+      };
+#endif
+  }
+
+  // 24.4.3  Move iterators
+  /**
+   *  Class template move_iterator is an iterator adapter with the same
+   *  behavior as the underlying iterator except that its dereference
+   *  operator implicitly converts the value returned by the underlying
+   *  iterator's dereference operator to an rvalue reference.  Some
+   *  generic algorithms can be called with move iterators to replace
+   *  copying with moving.
+   */
+  template<typename _Iterator>
+    class move_iterator
+#if __cplusplus > 201703L && __cpp_lib_concepts
+      : public __detail::__move_iter_cat<_Iterator>
+#endif
+    {
+      _Iterator _M_current;
+
+      using __traits_type = iterator_traits<_Iterator>;
+#if ! (__cplusplus > 201703L && __cpp_lib_concepts)
+      using __base_ref = typename __traits_type::reference;
+#endif
+
+      template<typename _Iter2>
+	friend class move_iterator;
+
+#if __cpp_lib_concepts
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 3435. three_way_comparable_with<reverse_iterator<int*>, [...]>
+      template<typename _Iter2>
+	static constexpr bool __convertible = !is_same_v<_Iter2, _Iterator>
+	    && convertible_to<const _Iter2&, _Iterator>;
+#endif
+
+    public:
+      using iterator_type = _Iterator;
+
+#if __cplusplus > 201703L && __cpp_lib_concepts
+      using iterator_concept = input_iterator_tag;
+      // iterator_category defined in __move_iter_cat
+      using value_type = iter_value_t<_Iterator>;
+      using difference_type = iter_difference_t<_Iterator>;
+      using pointer = _Iterator;
+      using reference = iter_rvalue_reference_t<_Iterator>;
+#else
+      typedef typename __traits_type::iterator_category iterator_category;
+      typedef typename __traits_type::value_type  	value_type;
+      typedef typename __traits_type::difference_type	difference_type;
+      // NB: DR 680.
+      typedef _Iterator					pointer;
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 2106. move_iterator wrapping iterators returning prvalues
+      using reference
+	= __conditional_t<is_reference<__base_ref>::value,
+			  typename remove_reference<__base_ref>::type&&,
+			  __base_ref>;
+#endif
+
+      _GLIBCXX17_CONSTEXPR
+      move_iterator()
+      : _M_current() { }
+
+      explicit _GLIBCXX17_CONSTEXPR
+      move_iterator(iterator_type __i)
+      : _M_current(std::move(__i)) { }
+
+      template<typename _Iter>
+#if __cpp_lib_concepts
+	requires __convertible<_Iter>
+#endif
+	_GLIBCXX17_CONSTEXPR
+	move_iterator(const move_iterator<_Iter>& __i)
+	: _M_current(__i._M_current) { }
+
+      template<typename _Iter>
+#if __cpp_lib_concepts
+	requires __convertible<_Iter>
+	  && assignable_from<_Iterator&, const _Iter&>
+#endif
+	_GLIBCXX17_CONSTEXPR
+	move_iterator& operator=(const move_iterator<_Iter>& __i)
+	{
+	  _M_current = __i._M_current;
+	  return *this;
+	}
+
+#if __cplusplus <= 201703L
+      [[__nodiscard__]]
+      _GLIBCXX17_CONSTEXPR iterator_type
+      base() const
+      { return _M_current; }
+#else
+      [[nodiscard]]
+      constexpr const iterator_type&
+      base() const & noexcept
+      { return _M_current; }
+
+      [[nodiscard]]
+      constexpr iterator_type
+      base() &&
+      { return std::move(_M_current); }
+#endif
+
+      [[__nodiscard__]]
+      _GLIBCXX17_CONSTEXPR reference
+      operator*() const
+#if __cplusplus > 201703L && __cpp_lib_concepts
+      { return ranges::iter_move(_M_current); }
+#else
+      { return static_cast<reference>(*_M_current); }
+#endif
+
+      [[__nodiscard__]]
+      _GLIBCXX17_CONSTEXPR pointer
+      operator->() const
+      { return _M_current; }
+
+      _GLIBCXX17_CONSTEXPR move_iterator&
+      operator++()
+      {
+	++_M_current;
+	return *this;
+      }
+
+      _GLIBCXX17_CONSTEXPR move_iterator
+      operator++(int)
+      {
+	move_iterator __tmp = *this;
+	++_M_current;
+	return __tmp;
+      }
+
+#if __cpp_lib_concepts
+      constexpr void
+      operator++(int) requires (!forward_iterator<_Iterator>)
+      { ++_M_current; }
+#endif
+
+      _GLIBCXX17_CONSTEXPR move_iterator&
+      operator--()
+      {
+	--_M_current;
+	return *this;
+      }
+
+      _GLIBCXX17_CONSTEXPR move_iterator
+      operator--(int)
+      {
+	move_iterator __tmp = *this;
+	--_M_current;
+	return __tmp;
+      }
+
+      [[__nodiscard__]]
+      _GLIBCXX17_CONSTEXPR move_iterator
+      operator+(difference_type __n) const
+      { return move_iterator(_M_current + __n); }
+
+      _GLIBCXX17_CONSTEXPR move_iterator&
+      operator+=(difference_type __n)
+      {
+	_M_current += __n;
+	return *this;
+      }
+
+      [[__nodiscard__]]
+      _GLIBCXX17_CONSTEXPR move_iterator
+      operator-(difference_type __n) const
+      { return move_iterator(_M_current - __n); }
+    
+      _GLIBCXX17_CONSTEXPR move_iterator&
+      operator-=(difference_type __n)
+      { 
+	_M_current -= __n;
+	return *this;
+      }
+
+      [[__nodiscard__]]
+      _GLIBCXX17_CONSTEXPR reference
+      operator[](difference_type __n) const
+#if __cplusplus > 201703L && __cpp_lib_concepts
+      { return ranges::iter_move(_M_current + __n); }
+#else
+      { return std::move(_M_current[__n]); }
+#endif
+
+#if __cplusplus > 201703L && __cpp_lib_concepts
+      template<sentinel_for<_Iterator> _Sent>
+	[[nodiscard]]
+	friend constexpr bool
+	operator==(const move_iterator& __x, const move_sentinel<_Sent>& __y)
+	{ return __x.base() == __y.base(); }
+
+      template<sized_sentinel_for<_Iterator> _Sent>
+	[[nodiscard]]
+	friend constexpr iter_difference_t<_Iterator>
+	operator-(const move_sentinel<_Sent>& __x, const move_iterator& __y)
+	{ return __x.base() - __y.base(); }
+
+      template<sized_sentinel_for<_Iterator> _Sent>
+	[[nodiscard]]
+	friend constexpr iter_difference_t<_Iterator>
+	operator-(const move_iterator& __x, const move_sentinel<_Sent>& __y)
+	{ return __x.base() - __y.base(); }
+
+      [[nodiscard]]
+      friend constexpr iter_rvalue_reference_t<_Iterator>
+      iter_move(const move_iterator& __i)
+      noexcept(noexcept(ranges::iter_move(__i._M_current)))
+      { return ranges::iter_move(__i._M_current); }
+
+      template<indirectly_swappable<_Iterator> _Iter2>
+	friend constexpr void
+	iter_swap(const move_iterator& __x, const move_iterator<_Iter2>& __y)
+	noexcept(noexcept(ranges::iter_swap(__x._M_current, __y._M_current)))
+	{ return ranges::iter_swap(__x._M_current, __y._M_current); }
+#endif // C++20
+    };
+
+  template<typename _IteratorL, typename _IteratorR>
+    [[__nodiscard__]]
+    inline _GLIBCXX17_CONSTEXPR bool
+    operator==(const move_iterator<_IteratorL>& __x,
+	       const move_iterator<_IteratorR>& __y)
+#if __cplusplus > 201703L && __cpp_lib_concepts
+    requires requires { { __x.base() == __y.base() } -> convertible_to<bool>; }
+#endif
+    { return __x.base() == __y.base(); }
+
+#if __cpp_lib_three_way_comparison
+  template<typename _IteratorL,
+	   three_way_comparable_with<_IteratorL> _IteratorR>
+    [[__nodiscard__]]
+    constexpr compare_three_way_result_t<_IteratorL, _IteratorR>
+    operator<=>(const move_iterator<_IteratorL>& __x,
+		const move_iterator<_IteratorR>& __y)
+    { return __x.base() <=> __y.base(); }
+#else
+  template<typename _IteratorL, typename _IteratorR>
+    [[__nodiscard__]]
+    inline _GLIBCXX17_CONSTEXPR bool
+    operator!=(const move_iterator<_IteratorL>& __x,
+	       const move_iterator<_IteratorR>& __y)
+    { return !(__x == __y); }
+#endif
+
+  template<typename _IteratorL, typename _IteratorR>
+    [[__nodiscard__]]
+    inline _GLIBCXX17_CONSTEXPR bool
+    operator<(const move_iterator<_IteratorL>& __x,
+	      const move_iterator<_IteratorR>& __y)
+#if __cplusplus > 201703L && __cpp_lib_concepts
+    requires requires { { __x.base() < __y.base() } -> convertible_to<bool>; }
+#endif
+    { return __x.base() < __y.base(); }
+
+  template<typename _IteratorL, typename _IteratorR>
+    [[__nodiscard__]]
+    inline _GLIBCXX17_CONSTEXPR bool
+    operator<=(const move_iterator<_IteratorL>& __x,
+	       const move_iterator<_IteratorR>& __y)
+#if __cplusplus > 201703L && __cpp_lib_concepts
+    requires requires { { __y.base() < __x.base() } -> convertible_to<bool>; }
+#endif
+    { return !(__y < __x); }
+
+  template<typename _IteratorL, typename _IteratorR>
+    [[__nodiscard__]]
+    inline _GLIBCXX17_CONSTEXPR bool
+    operator>(const move_iterator<_IteratorL>& __x,
+	      const move_iterator<_IteratorR>& __y)
+#if __cplusplus > 201703L && __cpp_lib_concepts
+    requires requires { { __y.base() < __x.base() } -> convertible_to<bool>; }
+#endif
+    { return __y < __x; }
+
+  template<typename _IteratorL, typename _IteratorR>
+    [[__nodiscard__]]
+    inline _GLIBCXX17_CONSTEXPR bool
+    operator>=(const move_iterator<_IteratorL>& __x,
+	       const move_iterator<_IteratorR>& __y)
+#if __cplusplus > 201703L && __cpp_lib_concepts
+    requires requires { { __x.base() < __y.base() } -> convertible_to<bool>; }
+#endif
+    { return !(__x < __y); }
+
+  // Note: See __normal_iterator operators note from Gaby to understand
+  // why we have these extra overloads for some move_iterator operators.
+
+  template<typename _Iterator>
+    [[__nodiscard__]]
+    inline _GLIBCXX17_CONSTEXPR bool
+    operator==(const move_iterator<_Iterator>& __x,
+	       const move_iterator<_Iterator>& __y)
+    { return __x.base() == __y.base(); }
+
+#if __cpp_lib_three_way_comparison
+  template<three_way_comparable _Iterator>
+    [[__nodiscard__]]
+    constexpr compare_three_way_result_t<_Iterator>
+    operator<=>(const move_iterator<_Iterator>& __x,
+		const move_iterator<_Iterator>& __y)
+    { return __x.base() <=> __y.base(); }
+#else
+  template<typename _Iterator>
+    [[__nodiscard__]]
+    inline _GLIBCXX17_CONSTEXPR bool
+    operator!=(const move_iterator<_Iterator>& __x,
+	       const move_iterator<_Iterator>& __y)
+    { return !(__x == __y); }
+
+  template<typename _Iterator>
+    [[__nodiscard__]]
+    inline _GLIBCXX17_CONSTEXPR bool
+    operator<(const move_iterator<_Iterator>& __x,
+	      const move_iterator<_Iterator>& __y)
+    { return __x.base() < __y.base(); }
+
+  template<typename _Iterator>
+    [[__nodiscard__]]
+    inline _GLIBCXX17_CONSTEXPR bool
+    operator<=(const move_iterator<_Iterator>& __x,
+	       const move_iterator<_Iterator>& __y)
+    { return !(__y < __x); }
+
+  template<typename _Iterator>
+    [[__nodiscard__]]
+    inline _GLIBCXX17_CONSTEXPR bool
+    operator>(const move_iterator<_Iterator>& __x,
+	      const move_iterator<_Iterator>& __y)
+    { return __y < __x; }
+
+  template<typename _Iterator>
+    [[__nodiscard__]]
+    inline _GLIBCXX17_CONSTEXPR bool
+    operator>=(const move_iterator<_Iterator>& __x,
+	       const move_iterator<_Iterator>& __y)
+    { return !(__x < __y); }
+#endif // ! C++20
+
+  // DR 685.
+  template<typename _IteratorL, typename _IteratorR>
+    [[__nodiscard__]]
+    inline _GLIBCXX17_CONSTEXPR auto
+    operator-(const move_iterator<_IteratorL>& __x,
+	      const move_iterator<_IteratorR>& __y)
+    -> decltype(__x.base() - __y.base())
+    { return __x.base() - __y.base(); }
+
+  template<typename _Iterator>
+    [[__nodiscard__]]
+    inline _GLIBCXX17_CONSTEXPR move_iterator<_Iterator>
+    operator+(typename move_iterator<_Iterator>::difference_type __n,
+	      const move_iterator<_Iterator>& __x)
+    { return __x + __n; }
+
+  template<typename _Iterator>
+    [[__nodiscard__]]
+    inline _GLIBCXX17_CONSTEXPR move_iterator<_Iterator>
+    make_move_iterator(_Iterator __i)
+    { return move_iterator<_Iterator>(std::move(__i)); }
+
+  template<typename _Iterator, typename _ReturnType
+    = __conditional_t<__move_if_noexcept_cond
+      <typename iterator_traits<_Iterator>::value_type>::value,
+		_Iterator, move_iterator<_Iterator>>>
+    inline _GLIBCXX17_CONSTEXPR _ReturnType
+    __make_move_if_noexcept_iterator(_Iterator __i)
+    { return _ReturnType(__i); }
+
+  // Overload for pointers that matches std::move_if_noexcept more closely,
+  // returning a constant iterator when we don't want to move.
+  template<typename _Tp, typename _ReturnType
+    = __conditional_t<__move_if_noexcept_cond<_Tp>::value,
+		      const _Tp*, move_iterator<_Tp*>>>
+    inline _GLIBCXX17_CONSTEXPR _ReturnType
+    __make_move_if_noexcept_iterator(_Tp* __i)
+    { return _ReturnType(__i); }
+
+#if __cplusplus > 201703L && __cpp_lib_concepts
+  // [iterators.common] Common iterators
+
+  namespace __detail
+  {
+    template<typename _It>
+      concept __common_iter_has_arrow = indirectly_readable<const _It>
+	&& (requires(const _It& __it) { __it.operator->(); }
+	    || is_reference_v<iter_reference_t<_It>>
+	    || constructible_from<iter_value_t<_It>, iter_reference_t<_It>>);
+
+    template<typename _It>
+      concept __common_iter_use_postfix_proxy
+	= (!requires (_It& __i) { { *__i++ } -> __can_reference; })
+	  && constructible_from<iter_value_t<_It>, iter_reference_t<_It>>
+	  && move_constructible<iter_value_t<_It>>;
+  } // namespace __detail
+
+  /// An iterator/sentinel adaptor for representing a non-common range.
+  template<input_or_output_iterator _It, sentinel_for<_It> _Sent>
+    requires (!same_as<_It, _Sent>) && copyable<_It>
+  class common_iterator
+  {
+    template<typename _Tp, typename _Up>
+      static constexpr bool
+      _S_noexcept1()
+      {
+	if constexpr (is_trivially_default_constructible_v<_Tp>)
+	  return is_nothrow_assignable_v<_Tp&, _Up>;
+	else
+	  return is_nothrow_constructible_v<_Tp, _Up>;
+      }
+
+    template<typename _It2, typename _Sent2>
+      static constexpr bool
+      _S_noexcept()
+      { return _S_noexcept1<_It, _It2>() && _S_noexcept1<_Sent, _Sent2>(); }
+
+    class __arrow_proxy
+    {
+      iter_value_t<_It> _M_keep;
+
+      constexpr
+      __arrow_proxy(iter_reference_t<_It>&& __x)
+      : _M_keep(std::move(__x)) { }
+
+      friend class common_iterator;
+
+    public:
+      constexpr const iter_value_t<_It>*
+      operator->() const noexcept
+      { return std::__addressof(_M_keep); }
+    };
+
+    class __postfix_proxy
+    {
+      iter_value_t<_It> _M_keep;
+
+      constexpr
+      __postfix_proxy(iter_reference_t<_It>&& __x)
+      : _M_keep(std::forward<iter_reference_t<_It>>(__x)) { }
+
+      friend class common_iterator;
+
+    public:
+      constexpr const iter_value_t<_It>&
+      operator*() const noexcept
+      { return _M_keep; }
+    };
+
+  public:
+    constexpr
+    common_iterator()
+    noexcept(is_nothrow_default_constructible_v<_It>)
+    requires default_initializable<_It>
+    : _M_it(), _M_index(0)
+    { }
+
+    constexpr
+    common_iterator(_It __i)
+    noexcept(is_nothrow_move_constructible_v<_It>)
+    : _M_it(std::move(__i)), _M_index(0)
+    { }
+
+    constexpr
+    common_iterator(_Sent __s)
+    noexcept(is_nothrow_move_constructible_v<_Sent>)
+    : _M_sent(std::move(__s)), _M_index(1)
+    { }
+
+    template<typename _It2, typename _Sent2>
+      requires convertible_to<const _It2&, _It>
+	&& convertible_to<const _Sent2&, _Sent>
+      constexpr
+      common_iterator(const common_iterator<_It2, _Sent2>& __x)
+      noexcept(_S_noexcept<const _It2&, const _Sent2&>())
+      : _M_valueless(), _M_index(__x._M_index)
+      {
+	__glibcxx_assert(__x._M_has_value());
+	if (_M_index == 0)
+	  {
+	    if constexpr (is_trivially_default_constructible_v<_It>)
+	      _M_it = std::move(__x._M_it);
+	    else
+	      std::construct_at(std::__addressof(_M_it), __x._M_it);
+	  }
+	else if (_M_index == 1)
+	  {
+	    if constexpr (is_trivially_default_constructible_v<_Sent>)
+	      _M_sent = std::move(__x._M_sent);
+	    else
+	      std::construct_at(std::__addressof(_M_sent), __x._M_sent);
+	  }
+      }
+
+    constexpr
+    common_iterator(const common_iterator& __x)
+    noexcept(_S_noexcept<const _It&, const _Sent&>())
+    : _M_valueless(), _M_index(__x._M_index)
+    {
+      if (_M_index == 0)
+	{
+	  if constexpr (is_trivially_default_constructible_v<_It>)
+	    _M_it = __x._M_it;
+	  else
+	    std::construct_at(std::__addressof(_M_it), __x._M_it);
+	}
+      else if (_M_index == 1)
+	{
+	  if constexpr (is_trivially_default_constructible_v<_Sent>)
+	    _M_sent = __x._M_sent;
+	  else
+	    std::construct_at(std::__addressof(_M_sent), __x._M_sent);
+	}
+    }
+
+    constexpr
+    common_iterator(common_iterator&& __x)
+    noexcept(_S_noexcept<_It, _Sent>())
+    : _M_valueless(), _M_index(__x._M_index)
+    {
+      if (_M_index == 0)
+	{
+	  if constexpr (is_trivially_default_constructible_v<_It>)
+	    _M_it = std::move(__x._M_it);
+	  else
+	    std::construct_at(std::__addressof(_M_it), std::move(__x._M_it));
+	}
+      else if (_M_index == 1)
+	{
+	  if constexpr (is_trivially_default_constructible_v<_Sent>)
+	    _M_sent = std::move(__x._M_sent);
+	  else
+	    std::construct_at(std::__addressof(_M_sent),
+			      std::move(__x._M_sent));
+	}
+    }
+
+    constexpr common_iterator&
+    operator=(const common_iterator&) = default;
+
+    constexpr common_iterator&
+    operator=(const common_iterator& __x)
+    noexcept(is_nothrow_copy_assignable_v<_It>
+	     && is_nothrow_copy_assignable_v<_Sent>
+	     && is_nothrow_copy_constructible_v<_It>
+	     && is_nothrow_copy_constructible_v<_Sent>)
+    requires (!is_trivially_copy_assignable_v<_It>
+		|| !is_trivially_copy_assignable_v<_Sent>)
+    {
+      _M_assign(__x);
+      return *this;
+    }
+
+    constexpr common_iterator&
+    operator=(common_iterator&&) = default;
+
+    constexpr common_iterator&
+    operator=(common_iterator&& __x)
+    noexcept(is_nothrow_move_assignable_v<_It>
+	     && is_nothrow_move_assignable_v<_Sent>
+	     && is_nothrow_move_constructible_v<_It>
+	     && is_nothrow_move_constructible_v<_Sent>)
+    requires (!is_trivially_move_assignable_v<_It>
+		|| !is_trivially_move_assignable_v<_Sent>)
+    {
+      _M_assign(std::move(__x));
+      return *this;
+    }
+
+    template<typename _It2, typename _Sent2>
+      requires convertible_to<const _It2&, _It>
+	&& convertible_to<const _Sent2&, _Sent>
+	&& assignable_from<_It&, const _It2&>
+	&& assignable_from<_Sent&, const _Sent2&>
+      constexpr common_iterator&
+      operator=(const common_iterator<_It2, _Sent2>& __x)
+      noexcept(is_nothrow_constructible_v<_It, const _It2&>
+	       && is_nothrow_constructible_v<_Sent, const _Sent2&>
+	       && is_nothrow_assignable_v<_It&, const _It2&>
+	       && is_nothrow_assignable_v<_Sent&, const _Sent2&>)
+      {
+	__glibcxx_assert(__x._M_has_value());
+	_M_assign(__x);
+	return *this;
+      }
+
+    constexpr
+    ~common_iterator()
+    {
+      if (_M_index == 0)
+	_M_it.~_It();
+      else if (_M_index == 1)
+	_M_sent.~_Sent();
+    }
+
+    [[nodiscard]]
+    constexpr decltype(auto)
+    operator*()
+    {
+      __glibcxx_assert(_M_index == 0);
+      return *_M_it;
+    }
+
+    [[nodiscard]]
+    constexpr decltype(auto)
+    operator*() const requires __detail::__dereferenceable<const _It>
+    {
+      __glibcxx_assert(_M_index == 0);
+      return *_M_it;
+    }
+
+    [[nodiscard]]
+    constexpr auto
+    operator->() const requires __detail::__common_iter_has_arrow<_It>
+    {
+      __glibcxx_assert(_M_index == 0);
+      if constexpr (is_pointer_v<_It> || requires { _M_it.operator->(); })
+	return _M_it;
+      else if constexpr (is_reference_v<iter_reference_t<_It>>)
+	{
+	  auto&& __tmp = *_M_it;
+	  return std::__addressof(__tmp);
+	}
+      else
+	return __arrow_proxy{*_M_it};
+    }
+
+    constexpr common_iterator&
+    operator++()
+    {
+      __glibcxx_assert(_M_index == 0);
+      ++_M_it;
+      return *this;
+    }
+
+    constexpr decltype(auto)
+    operator++(int)
+    {
+      __glibcxx_assert(_M_index == 0);
+      if constexpr (forward_iterator<_It>)
+	{
+	  common_iterator __tmp = *this;
+	  ++*this;
+	  return __tmp;
+	}
+      else if constexpr (!__detail::__common_iter_use_postfix_proxy<_It>)
+	return _M_it++;
+      else
+	{
+	  __postfix_proxy __p(**this);
+	  ++*this;
+	  return __p;
+	}
+    }
+
+    template<typename _It2, sentinel_for<_It> _Sent2>
+      requires sentinel_for<_Sent, _It2>
+      friend constexpr bool
+      operator== [[nodiscard]] (const common_iterator& __x,
+				const common_iterator<_It2, _Sent2>& __y)
+      {
+	switch(__x._M_index << 2 | __y._M_index)
+	  {
+	  case 0b0000:
+	  case 0b0101:
+	    return true;
+	  case 0b0001:
+	    return __x._M_it == __y._M_sent;
+	  case 0b0100:
+	    return __x._M_sent == __y._M_it;
+	  default:
+	    __glibcxx_assert(__x._M_has_value());
+	    __glibcxx_assert(__y._M_has_value());
+	    __builtin_unreachable();
+	  }
+      }
+
+    template<typename _It2, sentinel_for<_It> _Sent2>
+      requires sentinel_for<_Sent, _It2> && equality_comparable_with<_It, _It2>
+      friend constexpr bool
+      operator== [[nodiscard]] (const common_iterator& __x,
+				const common_iterator<_It2, _Sent2>& __y)
+      {
+	switch(__x._M_index << 2 | __y._M_index)
+	  {
+	  case 0b0101:
+	    return true;
+	  case 0b0000:
+	    return __x._M_it == __y._M_it;
+	  case 0b0001:
+	    return __x._M_it == __y._M_sent;
+	  case 0b0100:
+	    return __x._M_sent == __y._M_it;
+	  default:
+	    __glibcxx_assert(__x._M_has_value());
+	    __glibcxx_assert(__y._M_has_value());
+	    __builtin_unreachable();
+	  }
+      }
+
+    template<sized_sentinel_for<_It> _It2, sized_sentinel_for<_It> _Sent2>
+      requires sized_sentinel_for<_Sent, _It2>
+      friend constexpr iter_difference_t<_It2>
+      operator- [[nodiscard]] (const common_iterator& __x,
+			       const common_iterator<_It2, _Sent2>& __y)
+      {
+	switch(__x._M_index << 2 | __y._M_index)
+	  {
+	  case 0b0101:
+	    return 0;
+	  case 0b0000:
+	    return __x._M_it - __y._M_it;
+	  case 0b0001:
+	    return __x._M_it - __y._M_sent;
+	  case 0b0100:
+	    return __x._M_sent - __y._M_it;
+	  default:
+	    __glibcxx_assert(__x._M_has_value());
+	    __glibcxx_assert(__y._M_has_value());
+	    __builtin_unreachable();
+	  }
+      }
+
+    [[nodiscard]]
+    friend constexpr iter_rvalue_reference_t<_It>
+    iter_move(const common_iterator& __i)
+    noexcept(noexcept(ranges::iter_move(std::declval<const _It&>())))
+    requires input_iterator<_It>
+    {
+      __glibcxx_assert(__i._M_index == 0);
+      return ranges::iter_move(__i._M_it);
+    }
+
+    template<indirectly_swappable<_It> _It2, typename _Sent2>
+      friend constexpr void
+      iter_swap(const common_iterator& __x,
+		const common_iterator<_It2, _Sent2>& __y)
+      noexcept(noexcept(ranges::iter_swap(std::declval<const _It&>(),
+					  std::declval<const _It2&>())))
+      {
+	__glibcxx_assert(__x._M_index == 0);
+	__glibcxx_assert(__y._M_index == 0);
+	return ranges::iter_swap(__x._M_it, __y._M_it);
+      }
+
+  private:
+    template<input_or_output_iterator _It2, sentinel_for<_It2> _Sent2>
+      requires (!same_as<_It2, _Sent2>) && copyable<_It2>
+      friend class common_iterator;
+
+    constexpr bool
+    _M_has_value() const noexcept { return _M_index != _S_valueless; }
+
+    template<typename _CIt>
+      constexpr void
+      _M_assign(_CIt&& __x)
+      {
+	if (_M_index == __x._M_index)
+	  {
+	    if (_M_index == 0)
+	      _M_it = std::forward<_CIt>(__x)._M_it;
+	    else if (_M_index == 1)
+	      _M_sent = std::forward<_CIt>(__x)._M_sent;
+	  }
+	else
+	  {
+	    if (_M_index == 0)
+	      _M_it.~_It();
+	    else if (_M_index == 1)
+	      _M_sent.~_Sent();
+	    _M_index = _S_valueless;
+
+	    if (__x._M_index == 0)
+	      std::construct_at(std::__addressof(_M_it),
+				std::forward<_CIt>(__x)._M_it);
+	    else if (__x._M_index == 1)
+	      std::construct_at(std::__addressof(_M_sent),
+				std::forward<_CIt>(__x)._M_sent);
+	    _M_index = __x._M_index;
+	  }
+      }
+
+    union
+    {
+      _It _M_it;
+      _Sent _M_sent;
+      unsigned char _M_valueless;
+    };
+    unsigned char _M_index; // 0 == _M_it, 1 == _M_sent, 2 == valueless
+
+    static constexpr unsigned char _S_valueless{2};
+  };
+
+  template<typename _It, typename _Sent>
+    struct incrementable_traits<common_iterator<_It, _Sent>>
+    {
+      using difference_type = iter_difference_t<_It>;
+    };
+
+  template<input_iterator _It, typename _Sent>
+    struct iterator_traits<common_iterator<_It, _Sent>>
+    {
+    private:
+      template<typename _Iter>
+	struct __ptr
+	{
+	  using type = void;
+	};
+
+      template<typename _Iter>
+	requires __detail::__common_iter_has_arrow<_Iter>
+	struct __ptr<_Iter>
+	{
+	  using _CIter = common_iterator<_Iter, _Sent>;
+	  using type = decltype(std::declval<const _CIter&>().operator->());
+	};
+
+      static auto
+      _S_iter_cat()
+      {
+	using _Traits = iterator_traits<_It>;
+	if constexpr (requires { requires derived_from<typename _Traits::iterator_category,
+						       forward_iterator_tag>; })
+	  return forward_iterator_tag{};
+	else
+	  return input_iterator_tag{};
+      }
+
+    public:
+      using iterator_concept = __conditional_t<forward_iterator<_It>,
+					       forward_iterator_tag,
+					       input_iterator_tag>;
+      using iterator_category = decltype(_S_iter_cat());
+      using value_type = iter_value_t<_It>;
+      using difference_type = iter_difference_t<_It>;
+      using pointer = typename __ptr<_It>::type;
+      using reference = iter_reference_t<_It>;
+    };
+
+  // [iterators.counted] Counted iterators
+
+  namespace __detail
+  {
+    template<typename _It>
+      struct __counted_iter_value_type
+      { };
+
+    template<indirectly_readable _It>
+      struct __counted_iter_value_type<_It>
+      { using value_type = iter_value_t<_It>; };
+
+    template<typename _It>
+      struct __counted_iter_concept
+      { };
+
+    template<typename _It>
+      requires requires { typename _It::iterator_concept; }
+      struct __counted_iter_concept<_It>
+      { using iterator_concept = typename _It::iterator_concept; };
+
+    template<typename _It>
+      struct __counted_iter_cat
+      { };
+
+    template<typename _It>
+      requires requires { typename _It::iterator_category; }
+      struct __counted_iter_cat<_It>
+      { using iterator_category = typename _It::iterator_category; };
+  }
+
+  /// An iterator adaptor that keeps track of the distance to the end.
+  template<input_or_output_iterator _It>
+    class counted_iterator
+      : public __detail::__counted_iter_value_type<_It>,
+	public __detail::__counted_iter_concept<_It>,
+	public __detail::__counted_iter_cat<_It>
+    {
+    public:
+      using iterator_type = _It;
+      // value_type defined in __counted_iter_value_type
+      using difference_type = iter_difference_t<_It>;
+      // iterator_concept defined in __counted_iter_concept
+      // iterator_category defined in __counted_iter_cat
+
+      constexpr counted_iterator() requires default_initializable<_It> = default;
+
+      constexpr
+      counted_iterator(_It __i, iter_difference_t<_It> __n)
+      : _M_current(std::move(__i)), _M_length(__n)
+      { __glibcxx_assert(__n >= 0); }
+
+      template<typename _It2>
+	requires convertible_to<const _It2&, _It>
+	constexpr
+	counted_iterator(const counted_iterator<_It2>& __x)
+	: _M_current(__x._M_current), _M_length(__x._M_length)
+	{ }
+
+      template<typename _It2>
+	requires assignable_from<_It&, const _It2&>
+	constexpr counted_iterator&
+	operator=(const counted_iterator<_It2>& __x)
+	{
+	  _M_current = __x._M_current;
+	  _M_length = __x._M_length;
+	  return *this;
+	}
+
+      [[nodiscard]]
+      constexpr const _It&
+      base() const & noexcept
+      { return _M_current; }
+
+      [[nodiscard]]
+      constexpr _It
+      base() &&
+      noexcept(is_nothrow_move_constructible_v<_It>)
+      { return std::move(_M_current); }
+
+      [[nodiscard]]
+      constexpr iter_difference_t<_It>
+      count() const noexcept { return _M_length; }
+
+      [[nodiscard]]
+      constexpr decltype(auto)
+      operator*()
+      noexcept(noexcept(*_M_current))
+      {
+	__glibcxx_assert( _M_length > 0 );
+	return *_M_current;
+      }
+
+      [[nodiscard]]
+      constexpr decltype(auto)
+      operator*() const
+      noexcept(noexcept(*_M_current))
+      requires __detail::__dereferenceable<const _It>
+      {
+	__glibcxx_assert( _M_length > 0 );
+	return *_M_current;
+      }
+
+      [[nodiscard]]
+      constexpr auto
+      operator->() const noexcept
+      requires contiguous_iterator<_It>
+      { return std::to_address(_M_current); }
+
+      constexpr counted_iterator&
+      operator++()
+      {
+	__glibcxx_assert(_M_length > 0);
+	++_M_current;
+	--_M_length;
+	return *this;
+      }
+
+      constexpr decltype(auto)
+      operator++(int)
+      {
+	__glibcxx_assert(_M_length > 0);
+	--_M_length;
+	__try
+	  {
+	    return _M_current++;
+	  } __catch(...) {
+	    ++_M_length;
+	    __throw_exception_again;
+	  }
+      }
+
+      constexpr counted_iterator
+      operator++(int) requires forward_iterator<_It>
+      {
+	auto __tmp = *this;
+	++*this;
+	return __tmp;
+      }
+
+      constexpr counted_iterator&
+      operator--() requires bidirectional_iterator<_It>
+      {
+	--_M_current;
+	++_M_length;
+	return *this;
+      }
+
+      constexpr counted_iterator
+      operator--(int) requires bidirectional_iterator<_It>
+      {
+	auto __tmp = *this;
+	--*this;
+	return __tmp;
+      }
+
+      [[nodiscard]]
+      constexpr counted_iterator
+      operator+(iter_difference_t<_It> __n) const
+	requires random_access_iterator<_It>
+      { return counted_iterator(_M_current + __n, _M_length - __n); }
+
+      [[nodiscard]]
+      friend constexpr counted_iterator
+      operator+(iter_difference_t<_It> __n, const counted_iterator& __x)
+      requires random_access_iterator<_It>
+      { return __x + __n; }
+
+      constexpr counted_iterator&
+      operator+=(iter_difference_t<_It> __n)
+      requires random_access_iterator<_It>
+      {
+	__glibcxx_assert(__n <= _M_length);
+	_M_current += __n;
+	_M_length -= __n;
+	return *this;
+      }
+
+      [[nodiscard]]
+      constexpr counted_iterator
+      operator-(iter_difference_t<_It> __n) const
+      requires random_access_iterator<_It>
+      { return counted_iterator(_M_current - __n, _M_length + __n); }
+
+      template<common_with<_It> _It2>
+	[[nodiscard]]
+	friend constexpr iter_difference_t<_It2>
+	operator-(const counted_iterator& __x,
+		  const counted_iterator<_It2>& __y)
+	{ return __y._M_length - __x._M_length; }
+
+      [[nodiscard]]
+      friend constexpr iter_difference_t<_It>
+      operator-(const counted_iterator& __x, default_sentinel_t)
+      { return -__x._M_length; }
+
+      [[nodiscard]]
+      friend constexpr iter_difference_t<_It>
+      operator-(default_sentinel_t, const counted_iterator& __y)
+      { return __y._M_length; }
+
+      constexpr counted_iterator&
+      operator-=(iter_difference_t<_It> __n)
+      requires random_access_iterator<_It>
+      {
+	__glibcxx_assert(-__n <= _M_length);
+	_M_current -= __n;
+	_M_length += __n;
+	return *this;
+      }
+
+      [[nodiscard]]
+      constexpr decltype(auto)
+      operator[](iter_difference_t<_It> __n) const
+      noexcept(noexcept(_M_current[__n]))
+      requires random_access_iterator<_It>
+      {
+	__glibcxx_assert(__n < _M_length);
+	return _M_current[__n];
+      }
+
+      template<common_with<_It> _It2>
+	[[nodiscard]]
+	friend constexpr bool
+	operator==(const counted_iterator& __x,
+		   const counted_iterator<_It2>& __y)
+	{ return __x._M_length == __y._M_length; }
+
+      [[nodiscard]]
+      friend constexpr bool
+      operator==(const counted_iterator& __x, default_sentinel_t)
+      { return __x._M_length == 0; }
+
+      template<common_with<_It> _It2>
+	[[nodiscard]]
+	friend constexpr strong_ordering
+	operator<=>(const counted_iterator& __x,
+		    const counted_iterator<_It2>& __y)
+	{ return __y._M_length <=> __x._M_length; }
+
+      [[nodiscard]]
+      friend constexpr iter_rvalue_reference_t<_It>
+      iter_move(const counted_iterator& __i)
+      noexcept(noexcept(ranges::iter_move(__i._M_current)))
+      requires input_iterator<_It>
+      {
+	__glibcxx_assert( __i._M_length > 0 );
+	return ranges::iter_move(__i._M_current);
+      }
+
+      template<indirectly_swappable<_It> _It2>
+	friend constexpr void
+	iter_swap(const counted_iterator& __x,
+		  const counted_iterator<_It2>& __y)
+	noexcept(noexcept(ranges::iter_swap(__x._M_current, __y._M_current)))
+	{
+	  __glibcxx_assert( __x._M_length > 0 && __y._M_length > 0 );
+	  ranges::iter_swap(__x._M_current, __y._M_current);
+	}
+
+    private:
+      template<input_or_output_iterator _It2> friend class counted_iterator;
+
+      _It _M_current = _It();
+      iter_difference_t<_It> _M_length = 0;
+    };
+
+  template<input_iterator _It>
+    requires same_as<__detail::__iter_traits<_It>, iterator_traits<_It>>
+    struct iterator_traits<counted_iterator<_It>> : iterator_traits<_It>
+    {
+      using pointer = __conditional_t<contiguous_iterator<_It>,
+				      add_pointer_t<iter_reference_t<_It>>,
+				      void>;
+    };
+#endif // C++20
+
+  /// @} group iterators
+
+  template<typename _Iterator>
+    _GLIBCXX20_CONSTEXPR
+    auto
+    __niter_base(move_iterator<_Iterator> __it)
+    -> decltype(make_move_iterator(__niter_base(__it.base())))
+    { return make_move_iterator(__niter_base(__it.base())); }
+
+  template<typename _Iterator>
+    struct __is_move_iterator<move_iterator<_Iterator> >
+    {
+      enum { __value = 1 };
+      typedef __true_type __type;
+    };
+
+  template<typename _Iterator>
+    _GLIBCXX20_CONSTEXPR
+    auto
+    __miter_base(move_iterator<_Iterator> __it)
+    -> decltype(__miter_base(__it.base()))
+    { return __miter_base(__it.base()); }
+
+#define _GLIBCXX_MAKE_MOVE_ITERATOR(_Iter) std::make_move_iterator(_Iter)
+#define _GLIBCXX_MAKE_MOVE_IF_NOEXCEPT_ITERATOR(_Iter) \
+  std::__make_move_if_noexcept_iterator(_Iter)
+#else
+#define _GLIBCXX_MAKE_MOVE_ITERATOR(_Iter) (_Iter)
+#define _GLIBCXX_MAKE_MOVE_IF_NOEXCEPT_ITERATOR(_Iter) (_Iter)
+#endif // C++11
+
+#if __cpp_deduction_guides >= 201606
+  // These helper traits are used for deduction guides
+  // of associative containers.
+  template<typename _InputIterator>
+    using __iter_key_t = remove_const_t<
+    typename iterator_traits<_InputIterator>::value_type::first_type>;
+
+  template<typename _InputIterator>
+    using __iter_val_t =
+    typename iterator_traits<_InputIterator>::value_type::second_type;
+
+  template<typename _T1, typename _T2>
+    struct pair;
+
+  template<typename _InputIterator>
+    using __iter_to_alloc_t =
+    pair<add_const_t<__iter_key_t<_InputIterator>>,
+	 __iter_val_t<_InputIterator>>;
+#endif // __cpp_deduction_guides
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#ifdef _GLIBCXX_DEBUG
+# include <debug/stl_iterator.h>
+#endif
+
+#endif
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@@ -0,0 +1,257 @@
+// Functions used by iterators -*- C++ -*-
+
+// Copyright (C) 2001-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/*
+ *
+ * Copyright (c) 1994
+ * Hewlett-Packard Company
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Hewlett-Packard Company makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ *
+ *
+ * Copyright (c) 1996-1998
+ * Silicon Graphics Computer Systems, Inc.
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Silicon Graphics makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ */
+
+/** @file bits/stl_iterator_base_funcs.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{iterator}
+ *
+ *  This file contains all of the general iterator-related utility
+ *  functions, such as distance() and advance().
+ */
+
+#ifndef _STL_ITERATOR_BASE_FUNCS_H
+#define _STL_ITERATOR_BASE_FUNCS_H 1
+
+#pragma GCC system_header
+
+#include <bits/concept_check.h>
+#include <debug/assertions.h>
+#include <bits/stl_iterator_base_types.h>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+_GLIBCXX_BEGIN_NAMESPACE_CONTAINER
+  // Forward declaration for the overloads of __distance.
+  template <typename> struct _List_iterator;
+  template <typename> struct _List_const_iterator;
+_GLIBCXX_END_NAMESPACE_CONTAINER
+
+  template<typename _InputIterator>
+    inline _GLIBCXX14_CONSTEXPR
+    typename iterator_traits<_InputIterator>::difference_type
+    __distance(_InputIterator __first, _InputIterator __last,
+               input_iterator_tag)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
+
+      typename iterator_traits<_InputIterator>::difference_type __n = 0;
+      while (__first != __last)
+	{
+	  ++__first;
+	  ++__n;
+	}
+      return __n;
+    }
+
+  template<typename _RandomAccessIterator>
+    inline _GLIBCXX14_CONSTEXPR
+    typename iterator_traits<_RandomAccessIterator>::difference_type
+    __distance(_RandomAccessIterator __first, _RandomAccessIterator __last,
+               random_access_iterator_tag)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_RandomAccessIteratorConcept<
+				  _RandomAccessIterator>)
+      return __last - __first;
+    }
+
+#if _GLIBCXX_USE_CXX11_ABI
+  // Forward declaration because of the qualified call in distance.
+  template<typename _Tp>
+    ptrdiff_t
+    __distance(_GLIBCXX_STD_C::_List_iterator<_Tp>,
+	       _GLIBCXX_STD_C::_List_iterator<_Tp>,
+	       input_iterator_tag);
+
+  template<typename _Tp>
+    ptrdiff_t
+    __distance(_GLIBCXX_STD_C::_List_const_iterator<_Tp>,
+	       _GLIBCXX_STD_C::_List_const_iterator<_Tp>,
+	       input_iterator_tag);
+#endif
+
+#if __cplusplus >= 201103L
+  // Give better error if std::distance called with a non-Cpp17InputIterator.
+  template<typename _OutputIterator>
+    void
+    __distance(_OutputIterator, _OutputIterator, output_iterator_tag) = delete;
+#endif
+
+  /**
+   *  @brief A generalization of pointer arithmetic.
+   *  @param  __first  An input iterator.
+   *  @param  __last  An input iterator.
+   *  @return  The distance between them.
+   *
+   *  Returns @c n such that __first + n == __last.  This requires
+   *  that @p __last must be reachable from @p __first.  Note that @c
+   *  n may be negative.
+   *
+   *  For random access iterators, this uses their @c + and @c - operations
+   *  and are constant time.  For other %iterator classes they are linear time.
+  */
+  template<typename _InputIterator>
+    _GLIBCXX_NODISCARD
+    inline _GLIBCXX17_CONSTEXPR
+    typename iterator_traits<_InputIterator>::difference_type
+    distance(_InputIterator __first, _InputIterator __last)
+    {
+      // concept requirements -- taken care of in __distance
+      return std::__distance(__first, __last,
+			     std::__iterator_category(__first));
+    }
+
+  template<typename _InputIterator, typename _Distance>
+    inline _GLIBCXX14_CONSTEXPR void
+    __advance(_InputIterator& __i, _Distance __n, input_iterator_tag)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
+      __glibcxx_assert(__n >= 0);
+      while (__n--)
+	++__i;
+    }
+
+  template<typename _BidirectionalIterator, typename _Distance>
+    inline _GLIBCXX14_CONSTEXPR void
+    __advance(_BidirectionalIterator& __i, _Distance __n,
+	      bidirectional_iterator_tag)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_BidirectionalIteratorConcept<
+				  _BidirectionalIterator>)
+      if (__n > 0)
+        while (__n--)
+	  ++__i;
+      else
+        while (__n++)
+	  --__i;
+    }
+
+  template<typename _RandomAccessIterator, typename _Distance>
+    inline _GLIBCXX14_CONSTEXPR void
+    __advance(_RandomAccessIterator& __i, _Distance __n,
+              random_access_iterator_tag)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_RandomAccessIteratorConcept<
+				  _RandomAccessIterator>)
+      if (__builtin_constant_p(__n) && __n == 1)
+	++__i;
+      else if (__builtin_constant_p(__n) && __n == -1)
+	--__i;
+      else
+	__i += __n;
+    }
+
+#if __cplusplus >= 201103L
+  // Give better error if std::advance called with a non-Cpp17InputIterator.
+  template<typename _OutputIterator, typename _Distance>
+    void
+    __advance(_OutputIterator&, _Distance, output_iterator_tag) = delete;
+#endif
+
+  /**
+   *  @brief A generalization of pointer arithmetic.
+   *  @param  __i  An input iterator.
+   *  @param  __n  The @a delta by which to change @p __i.
+   *  @return  Nothing.
+   *
+   *  This increments @p i by @p n.  For bidirectional and random access
+   *  iterators, @p __n may be negative, in which case @p __i is decremented.
+   *
+   *  For random access iterators, this uses their @c + and @c - operations
+   *  and are constant time.  For other %iterator classes they are linear time.
+  */
+  template<typename _InputIterator, typename _Distance>
+    inline _GLIBCXX17_CONSTEXPR void
+    advance(_InputIterator& __i, _Distance __n)
+    {
+      // concept requirements -- taken care of in __advance
+      typename iterator_traits<_InputIterator>::difference_type __d = __n;
+      std::__advance(__i, __d, std::__iterator_category(__i));
+    }
+
+#if __cplusplus >= 201103L
+
+  template<typename _InputIterator>
+    _GLIBCXX_NODISCARD
+    inline _GLIBCXX17_CONSTEXPR _InputIterator
+    next(_InputIterator __x, typename
+	 iterator_traits<_InputIterator>::difference_type __n = 1)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
+      std::advance(__x, __n);
+      return __x;
+    }
+
+  template<typename _BidirectionalIterator>
+    _GLIBCXX_NODISCARD
+    inline _GLIBCXX17_CONSTEXPR _BidirectionalIterator
+    prev(_BidirectionalIterator __x, typename
+	 iterator_traits<_BidirectionalIterator>::difference_type __n = 1) 
+    {
+      // concept requirements
+      __glibcxx_function_requires(_BidirectionalIteratorConcept<
+				  _BidirectionalIterator>)
+      std::advance(__x, -__n);
+      return __x;
+    }
+
+#endif // C++11
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif /* _STL_ITERATOR_BASE_FUNCS_H */
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stl_iterator_base_types.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stl_iterator_base_types.h
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@@ -0,0 +1,271 @@
+// Types used in iterator implementation -*- C++ -*-
+
+// Copyright (C) 2001-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/*
+ *
+ * Copyright (c) 1994
+ * Hewlett-Packard Company
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Hewlett-Packard Company makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ *
+ *
+ * Copyright (c) 1996-1998
+ * Silicon Graphics Computer Systems, Inc.
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Silicon Graphics makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ */
+
+/** @file bits/stl_iterator_base_types.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{iterator}
+ *
+ *  This file contains all of the general iterator-related utility types,
+ *  such as iterator_traits and struct iterator.
+ */
+
+#ifndef _STL_ITERATOR_BASE_TYPES_H
+#define _STL_ITERATOR_BASE_TYPES_H 1
+
+#pragma GCC system_header
+
+#include <bits/c++config.h>
+
+#if __cplusplus >= 201103L
+# include <type_traits>  // For __void_t, is_convertible
+#endif
+
+#if __cplusplus > 201703L && __cpp_concepts >= 201907L
+# include <bits/iterator_concepts.h>
+#endif
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /**
+   *  @defgroup iterators Iterators
+   *  Abstractions for uniform iterating through various underlying types.
+  */
+  ///@{
+
+  /**
+   *  @defgroup iterator_tags Iterator Tags
+   *  These are empty types, used to distinguish different iterators.  The
+   *  distinction is not made by what they contain, but simply by what they
+   *  are.  Different underlying algorithms can then be used based on the
+   *  different operations supported by different iterator types.
+  */
+  ///@{
+  ///  Marking input iterators.
+  struct input_iterator_tag { };
+
+  ///  Marking output iterators.
+  struct output_iterator_tag { };
+
+  /// Forward iterators support a superset of input iterator operations.
+  struct forward_iterator_tag : public input_iterator_tag { };
+
+  /// Bidirectional iterators support a superset of forward iterator
+  /// operations.
+  struct bidirectional_iterator_tag : public forward_iterator_tag { };
+
+  /// Random-access iterators support a superset of bidirectional
+  /// iterator operations.
+  struct random_access_iterator_tag : public bidirectional_iterator_tag { };
+
+#if __cplusplus > 201703L
+  /// Contiguous iterators point to objects stored contiguously in memory.
+  struct contiguous_iterator_tag : public random_access_iterator_tag { };
+#endif
+  ///@}
+
+  /**
+   *  @brief  Common %iterator class.
+   *
+   *  This class does nothing but define nested typedefs.  %Iterator classes
+   *  can inherit from this class to save some work.  The typedefs are then
+   *  used in specializations and overloading.
+   *
+   *  In particular, there are no default implementations of requirements
+   *  such as @c operator++ and the like.  (How could there be?)
+  */
+  template<typename _Category, typename _Tp, typename _Distance = ptrdiff_t,
+           typename _Pointer = _Tp*, typename _Reference = _Tp&>
+    struct _GLIBCXX17_DEPRECATED iterator
+    {
+      /// One of the @link iterator_tags tag types@endlink.
+      typedef _Category  iterator_category;
+      /// The type "pointed to" by the iterator.
+      typedef _Tp        value_type;
+      /// Distance between iterators is represented as this type.
+      typedef _Distance  difference_type;
+      /// This type represents a pointer-to-value_type.
+      typedef _Pointer   pointer;
+      /// This type represents a reference-to-value_type.
+      typedef _Reference reference;
+    };
+
+  /**
+   *  @brief  Traits class for iterators.
+   *
+   *  This class does nothing but define nested typedefs.  The general
+   *  version simply @a forwards the nested typedefs from the Iterator
+   *  argument.  Specialized versions for pointers and pointers-to-const
+   *  provide tighter, more correct semantics.
+  */
+  template<typename _Iterator>
+    struct iterator_traits;
+
+#if __cplusplus >= 201103L
+  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+  // 2408. SFINAE-friendly common_type/iterator_traits is missing in C++14
+  template<typename _Iterator, typename = __void_t<>>
+    struct __iterator_traits { };
+
+#if ! __cpp_lib_concepts
+
+  template<typename _Iterator>
+    struct __iterator_traits<_Iterator,
+			     __void_t<typename _Iterator::iterator_category,
+				      typename _Iterator::value_type,
+				      typename _Iterator::difference_type,
+				      typename _Iterator::pointer,
+				      typename _Iterator::reference>>
+    {
+      typedef typename _Iterator::iterator_category iterator_category;
+      typedef typename _Iterator::value_type        value_type;
+      typedef typename _Iterator::difference_type   difference_type;
+      typedef typename _Iterator::pointer           pointer;
+      typedef typename _Iterator::reference         reference;
+    };
+#endif // ! concepts
+
+  template<typename _Iterator>
+    struct iterator_traits
+    : public __iterator_traits<_Iterator> { };
+
+#else // ! C++11
+  template<typename _Iterator>
+    struct iterator_traits
+    {
+      typedef typename _Iterator::iterator_category iterator_category;
+      typedef typename _Iterator::value_type        value_type;
+      typedef typename _Iterator::difference_type   difference_type;
+      typedef typename _Iterator::pointer           pointer;
+      typedef typename _Iterator::reference         reference;
+    };
+#endif // C++11
+
+#if __cplusplus > 201703L
+  /// Partial specialization for object pointer types.
+  template<typename _Tp>
+#if __cpp_concepts >= 201907L
+    requires is_object_v<_Tp>
+#endif
+    struct iterator_traits<_Tp*>
+    {
+      using iterator_concept  = contiguous_iterator_tag;
+      using iterator_category = random_access_iterator_tag;
+      using value_type	      = remove_cv_t<_Tp>;
+      using difference_type   = ptrdiff_t;
+      using pointer	      = _Tp*;
+      using reference	      = _Tp&;
+    };
+#else
+  /// Partial specialization for pointer types.
+  template<typename _Tp>
+    struct iterator_traits<_Tp*>
+    {
+      typedef random_access_iterator_tag iterator_category;
+      typedef _Tp                         value_type;
+      typedef ptrdiff_t                   difference_type;
+      typedef _Tp*                        pointer;
+      typedef _Tp&                        reference;
+    };
+
+  /// Partial specialization for const pointer types.
+  template<typename _Tp>
+    struct iterator_traits<const _Tp*>
+    {
+      typedef random_access_iterator_tag iterator_category;
+      typedef _Tp                         value_type;
+      typedef ptrdiff_t                   difference_type;
+      typedef const _Tp*                  pointer;
+      typedef const _Tp&                  reference;
+    };
+#endif
+
+  /**
+   *  This function is not a part of the C++ standard but is syntactic
+   *  sugar for internal library use only.
+  */
+  template<typename _Iter>
+    inline _GLIBCXX_CONSTEXPR
+    typename iterator_traits<_Iter>::iterator_category
+    __iterator_category(const _Iter&)
+    { return typename iterator_traits<_Iter>::iterator_category(); }
+
+  ///@}
+
+#if __cplusplus >= 201103L
+  template<typename _Iter>
+    using __iterator_category_t
+      = typename iterator_traits<_Iter>::iterator_category;
+
+  template<typename _InIter>
+    using _RequireInputIter =
+      __enable_if_t<is_convertible<__iterator_category_t<_InIter>,
+				   input_iterator_tag>::value>;
+
+  template<typename _It,
+	   typename _Cat = __iterator_category_t<_It>>
+    struct __is_random_access_iter
+      : is_base_of<random_access_iterator_tag, _Cat>
+    {
+      typedef is_base_of<random_access_iterator_tag, _Cat> _Base;
+      enum { __value = _Base::value };
+    };
+#else
+  template<typename _It, typename _Traits = iterator_traits<_It>,
+	   typename _Cat = typename _Traits::iterator_category>
+    struct __is_random_access_iter
+    { enum { __value = __is_base_of(random_access_iterator_tag, _Cat) }; };
+#endif
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif /* _STL_ITERATOR_BASE_TYPES_H */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stl_iterator_base_types.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stl_iterator_base_types.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stl_list.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stl_list.h
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stl_list.h
@@ -0,0 +1,2262 @@
+// List implementation -*- C++ -*-
+
+// Copyright (C) 2001-2022 Free Software Foundation, Inc.
+// Copyright The GNU Toolchain Authors.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/*
+ *
+ * Copyright (c) 1994
+ * Hewlett-Packard Company
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Hewlett-Packard Company makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ *
+ *
+ * Copyright (c) 1996,1997
+ * Silicon Graphics Computer Systems, Inc.
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Silicon Graphics makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ */
+
+/** @file bits/stl_list.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{list}
+ */
+
+#ifndef _STL_LIST_H
+#define _STL_LIST_H 1
+
+#include <bits/concept_check.h>
+#include <ext/alloc_traits.h>
+#if __cplusplus >= 201103L
+#include <initializer_list>
+#include <bits/allocated_ptr.h>
+#include <ext/aligned_buffer.h>
+#endif
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  namespace __detail
+  {
+    // Supporting structures are split into common and templated
+    // types; the latter publicly inherits from the former in an
+    // effort to reduce code duplication.  This results in some
+    // "needless" static_cast'ing later on, but it's all safe
+    // downcasting.
+
+    /// Common part of a node in the %list.
+    struct _List_node_base
+    {
+      _List_node_base* _M_next;
+      _List_node_base* _M_prev;
+
+      static void
+      swap(_List_node_base& __x, _List_node_base& __y) _GLIBCXX_USE_NOEXCEPT;
+
+      void
+      _M_transfer(_List_node_base* const __first,
+		  _List_node_base* const __last) _GLIBCXX_USE_NOEXCEPT;
+
+      void
+      _M_reverse() _GLIBCXX_USE_NOEXCEPT;
+
+      void
+      _M_hook(_List_node_base* const __position) _GLIBCXX_USE_NOEXCEPT;
+
+      void
+      _M_unhook() _GLIBCXX_USE_NOEXCEPT;
+    };
+
+    /// The %list node header.
+    struct _List_node_header : public _List_node_base
+    {
+#if _GLIBCXX_USE_CXX11_ABI
+      std::size_t _M_size;
+#endif
+
+      _List_node_header() _GLIBCXX_NOEXCEPT
+      { _M_init(); }
+
+#if __cplusplus >= 201103L
+      _List_node_header(_List_node_header&& __x) noexcept
+      : _List_node_base{ __x._M_next, __x._M_prev }
+# if _GLIBCXX_USE_CXX11_ABI
+      , _M_size(__x._M_size)
+# endif
+      {
+	if (__x._M_base()->_M_next == __x._M_base())
+	  this->_M_next = this->_M_prev = this;
+	else
+	  {
+	    this->_M_next->_M_prev = this->_M_prev->_M_next = this->_M_base();
+	    __x._M_init();
+	  }
+      }
+
+      void
+      _M_move_nodes(_List_node_header&& __x)
+      {
+	_List_node_base* const __xnode = __x._M_base();
+	if (__xnode->_M_next == __xnode)
+	  _M_init();
+	else
+	  {
+	    _List_node_base* const __node = this->_M_base();
+	    __node->_M_next = __xnode->_M_next;
+	    __node->_M_prev = __xnode->_M_prev;
+	    __node->_M_next->_M_prev = __node->_M_prev->_M_next = __node;
+# if _GLIBCXX_USE_CXX11_ABI
+	    _M_size = __x._M_size;
+# endif
+	    __x._M_init();
+	  }
+      }
+#endif
+
+      void
+      _M_init() _GLIBCXX_NOEXCEPT
+      {
+	this->_M_next = this->_M_prev = this;
+#if _GLIBCXX_USE_CXX11_ABI
+	this->_M_size = 0;
+#endif
+      }
+
+    private:
+      _List_node_base* _M_base() { return this; }
+    };
+
+    // Used by list::sort to hold nodes being sorted.
+    struct _Scratch_list : _List_node_base
+    {
+      _Scratch_list() { _M_next = _M_prev = this; }
+
+      bool empty() const { return _M_next == this; }
+
+      void swap(_List_node_base& __l) { _List_node_base::swap(*this, __l); }
+
+      template<typename _Iter, typename _Cmp>
+	struct _Ptr_cmp
+	{
+	  _Cmp _M_cmp;
+
+	  bool
+	  operator()(__detail::_List_node_base* __lhs,
+		     __detail::_List_node_base* __rhs) /* not const */
+	  { return _M_cmp(*_Iter(__lhs), *_Iter(__rhs)); }
+	};
+
+      template<typename _Iter>
+	struct _Ptr_cmp<_Iter, void>
+	{
+	  bool
+	  operator()(__detail::_List_node_base* __lhs,
+		     __detail::_List_node_base* __rhs) const
+	  { return *_Iter(__lhs) < *_Iter(__rhs); }
+	};
+
+      // Merge nodes from __x into *this. Both lists must be sorted wrt _Cmp.
+      template<typename _Cmp>
+	void
+	merge(_List_node_base& __x, _Cmp __comp)
+	{
+	  _List_node_base* __first1 = _M_next;
+	  _List_node_base* const __last1 = this;
+	  _List_node_base* __first2 = __x._M_next;
+	  _List_node_base* const __last2 = std::__addressof(__x);
+
+	  while (__first1 != __last1 && __first2 != __last2)
+	    {
+	      if (__comp(__first2, __first1))
+		{
+		  _List_node_base* __next = __first2->_M_next;
+		  __first1->_M_transfer(__first2, __next);
+		  __first2 = __next;
+		}
+	      else
+		__first1 = __first1->_M_next;
+	    }
+	  if (__first2 != __last2)
+	    this->_M_transfer(__first2, __last2);
+	}
+
+      // Splice the node at __i into *this.
+      void _M_take_one(_List_node_base* __i)
+      { this->_M_transfer(__i, __i->_M_next); }
+
+      // Splice all nodes from *this after __i.
+      void _M_put_all(_List_node_base* __i)
+      {
+	if (!empty())
+	  __i->_M_transfer(_M_next, this);
+      }
+    };
+
+  } // namespace detail
+
+_GLIBCXX_BEGIN_NAMESPACE_CONTAINER
+
+  /// An actual node in the %list.
+  template<typename _Tp>
+    struct _List_node : public __detail::_List_node_base
+    {
+#if __cplusplus >= 201103L
+      __gnu_cxx::__aligned_membuf<_Tp> _M_storage;
+      _Tp*       _M_valptr()       { return _M_storage._M_ptr(); }
+      _Tp const* _M_valptr() const { return _M_storage._M_ptr(); }
+#else
+      _Tp _M_data;
+      _Tp*       _M_valptr()       { return std::__addressof(_M_data); }
+      _Tp const* _M_valptr() const { return std::__addressof(_M_data); }
+#endif
+    };
+
+  /**
+   *  @brief A list::iterator.
+   *
+   *  All the functions are op overloads.
+  */
+  template<typename _Tp>
+    struct _List_iterator
+    {
+      typedef _List_iterator<_Tp>		_Self;
+      typedef _List_node<_Tp>			_Node;
+
+      typedef ptrdiff_t				difference_type;
+      typedef std::bidirectional_iterator_tag	iterator_category;
+      typedef _Tp				value_type;
+      typedef _Tp*				pointer;
+      typedef _Tp&				reference;
+
+      _List_iterator() _GLIBCXX_NOEXCEPT
+      : _M_node() { }
+
+      explicit
+      _List_iterator(__detail::_List_node_base* __x) _GLIBCXX_NOEXCEPT
+      : _M_node(__x) { }
+
+      _Self
+      _M_const_cast() const _GLIBCXX_NOEXCEPT
+      { return *this; }
+
+      // Must downcast from _List_node_base to _List_node to get to value.
+      _GLIBCXX_NODISCARD
+      reference
+      operator*() const _GLIBCXX_NOEXCEPT
+      { return *static_cast<_Node*>(_M_node)->_M_valptr(); }
+
+      _GLIBCXX_NODISCARD
+      pointer
+      operator->() const _GLIBCXX_NOEXCEPT
+      { return static_cast<_Node*>(_M_node)->_M_valptr(); }
+
+      _Self&
+      operator++() _GLIBCXX_NOEXCEPT
+      {
+	_M_node = _M_node->_M_next;
+	return *this;
+      }
+
+      _Self
+      operator++(int) _GLIBCXX_NOEXCEPT
+      {
+	_Self __tmp = *this;
+	_M_node = _M_node->_M_next;
+	return __tmp;
+      }
+
+      _Self&
+      operator--() _GLIBCXX_NOEXCEPT
+      {
+	_M_node = _M_node->_M_prev;
+	return *this;
+      }
+
+      _Self
+      operator--(int) _GLIBCXX_NOEXCEPT
+      {
+	_Self __tmp = *this;
+	_M_node = _M_node->_M_prev;
+	return __tmp;
+      }
+
+      _GLIBCXX_NODISCARD
+      friend bool
+      operator==(const _Self& __x, const _Self& __y) _GLIBCXX_NOEXCEPT
+      { return __x._M_node == __y._M_node; }
+
+#if __cpp_impl_three_way_comparison < 201907L
+      _GLIBCXX_NODISCARD
+      friend bool
+      operator!=(const _Self& __x, const _Self& __y) _GLIBCXX_NOEXCEPT
+      { return __x._M_node != __y._M_node; }
+#endif
+
+      // The only member points to the %list element.
+      __detail::_List_node_base* _M_node;
+    };
+
+  /**
+   *  @brief A list::const_iterator.
+   *
+   *  All the functions are op overloads.
+  */
+  template<typename _Tp>
+    struct _List_const_iterator
+    {
+      typedef _List_const_iterator<_Tp>		_Self;
+      typedef const _List_node<_Tp>		_Node;
+      typedef _List_iterator<_Tp>		iterator;
+
+      typedef ptrdiff_t				difference_type;
+      typedef std::bidirectional_iterator_tag	iterator_category;
+      typedef _Tp				value_type;
+      typedef const _Tp*			pointer;
+      typedef const _Tp&			reference;
+
+      _List_const_iterator() _GLIBCXX_NOEXCEPT
+      : _M_node() { }
+
+      explicit
+      _List_const_iterator(const __detail::_List_node_base* __x)
+      _GLIBCXX_NOEXCEPT
+      : _M_node(__x) { }
+
+      _List_const_iterator(const iterator& __x) _GLIBCXX_NOEXCEPT
+      : _M_node(__x._M_node) { }
+
+      iterator
+      _M_const_cast() const _GLIBCXX_NOEXCEPT
+      { return iterator(const_cast<__detail::_List_node_base*>(_M_node)); }
+
+      // Must downcast from List_node_base to _List_node to get to value.
+      _GLIBCXX_NODISCARD
+      reference
+      operator*() const _GLIBCXX_NOEXCEPT
+      { return *static_cast<_Node*>(_M_node)->_M_valptr(); }
+
+      _GLIBCXX_NODISCARD
+      pointer
+      operator->() const _GLIBCXX_NOEXCEPT
+      { return static_cast<_Node*>(_M_node)->_M_valptr(); }
+
+      _Self&
+      operator++() _GLIBCXX_NOEXCEPT
+      {
+	_M_node = _M_node->_M_next;
+	return *this;
+      }
+
+      _Self
+      operator++(int) _GLIBCXX_NOEXCEPT
+      {
+	_Self __tmp = *this;
+	_M_node = _M_node->_M_next;
+	return __tmp;
+      }
+
+      _Self&
+      operator--() _GLIBCXX_NOEXCEPT
+      {
+	_M_node = _M_node->_M_prev;
+	return *this;
+      }
+
+      _Self
+      operator--(int) _GLIBCXX_NOEXCEPT
+      {
+	_Self __tmp = *this;
+	_M_node = _M_node->_M_prev;
+	return __tmp;
+      }
+
+      _GLIBCXX_NODISCARD
+      friend bool
+      operator==(const _Self& __x, const _Self& __y) _GLIBCXX_NOEXCEPT
+      { return __x._M_node == __y._M_node; }
+
+#if __cpp_impl_three_way_comparison < 201907L
+      _GLIBCXX_NODISCARD
+      friend bool
+      operator!=(const _Self& __x, const _Self& __y) _GLIBCXX_NOEXCEPT
+      { return __x._M_node != __y._M_node; }
+#endif
+
+      // The only member points to the %list element.
+      const __detail::_List_node_base* _M_node;
+    };
+
+_GLIBCXX_BEGIN_NAMESPACE_CXX11
+  /// See bits/stl_deque.h's _Deque_base for an explanation.
+  template<typename _Tp, typename _Alloc>
+    class _List_base
+    {
+    protected:
+      typedef typename __gnu_cxx::__alloc_traits<_Alloc>::template
+	rebind<_Tp>::other				_Tp_alloc_type;
+      typedef __gnu_cxx::__alloc_traits<_Tp_alloc_type>	_Tp_alloc_traits;
+      typedef typename _Tp_alloc_traits::template
+	rebind<_List_node<_Tp> >::other _Node_alloc_type;
+      typedef __gnu_cxx::__alloc_traits<_Node_alloc_type> _Node_alloc_traits;
+
+#if !_GLIBCXX_INLINE_VERSION
+      static size_t
+      _S_distance(const __detail::_List_node_base* __first,
+		  const __detail::_List_node_base* __last)
+      {
+	size_t __n = 0;
+	while (__first != __last)
+	  {
+	    __first = __first->_M_next;
+	    ++__n;
+	  }
+	return __n;
+      }
+#endif
+
+      struct _List_impl
+      : public _Node_alloc_type
+      {
+	__detail::_List_node_header _M_node;
+
+	_List_impl() _GLIBCXX_NOEXCEPT_IF(
+	    is_nothrow_default_constructible<_Node_alloc_type>::value)
+	: _Node_alloc_type()
+	{ }
+
+	_List_impl(const _Node_alloc_type& __a) _GLIBCXX_NOEXCEPT
+	: _Node_alloc_type(__a)
+	{ }
+
+#if __cplusplus >= 201103L
+	_List_impl(_List_impl&&) = default;
+
+	_List_impl(_Node_alloc_type&& __a, _List_impl&& __x)
+	: _Node_alloc_type(std::move(__a)), _M_node(std::move(__x._M_node))
+	{ }
+
+	_List_impl(_Node_alloc_type&& __a) noexcept
+	: _Node_alloc_type(std::move(__a))
+	{ }
+#endif
+      };
+
+      _List_impl _M_impl;
+
+#if _GLIBCXX_USE_CXX11_ABI
+      size_t _M_get_size() const { return _M_impl._M_node._M_size; }
+
+      void _M_set_size(size_t __n) { _M_impl._M_node._M_size = __n; }
+
+      void _M_inc_size(size_t __n) { _M_impl._M_node._M_size += __n; }
+
+      void _M_dec_size(size_t __n) { _M_impl._M_node._M_size -= __n; }
+
+# if !_GLIBCXX_INLINE_VERSION
+      size_t
+      _M_distance(const __detail::_List_node_base* __first,
+		  const __detail::_List_node_base* __last) const
+      { return _S_distance(__first, __last); }
+
+      // return the stored size
+      size_t _M_node_count() const { return _M_get_size(); }
+# endif
+#else
+      // dummy implementations used when the size is not stored
+      size_t _M_get_size() const { return 0; }
+      void _M_set_size(size_t) { }
+      void _M_inc_size(size_t) { }
+      void _M_dec_size(size_t) { }
+
+# if !_GLIBCXX_INLINE_VERSION
+      size_t _M_distance(const void*, const void*) const { return 0; }
+
+      // count the number of nodes
+      size_t _M_node_count() const
+      {
+	return _S_distance(_M_impl._M_node._M_next,
+			   std::__addressof(_M_impl._M_node));
+      }
+# endif
+#endif
+
+      typename _Node_alloc_traits::pointer
+      _M_get_node()
+      { return _Node_alloc_traits::allocate(_M_impl, 1); }
+
+      void
+      _M_put_node(typename _Node_alloc_traits::pointer __p) _GLIBCXX_NOEXCEPT
+      { _Node_alloc_traits::deallocate(_M_impl, __p, 1); }
+
+  public:
+      typedef _Alloc allocator_type;
+
+      _Node_alloc_type&
+      _M_get_Node_allocator() _GLIBCXX_NOEXCEPT
+      { return _M_impl; }
+
+      const _Node_alloc_type&
+      _M_get_Node_allocator() const _GLIBCXX_NOEXCEPT
+      { return _M_impl; }
+
+#if __cplusplus >= 201103L
+      _List_base() = default;
+#else
+      _List_base() { }
+#endif
+
+      _List_base(const _Node_alloc_type& __a) _GLIBCXX_NOEXCEPT
+      : _M_impl(__a)
+      { }
+
+#if __cplusplus >= 201103L
+      _List_base(_List_base&&) = default;
+
+# if !_GLIBCXX_INLINE_VERSION
+      _List_base(_List_base&& __x, _Node_alloc_type&& __a)
+      : _M_impl(std::move(__a))
+      {
+	if (__x._M_get_Node_allocator() == _M_get_Node_allocator())
+	  _M_move_nodes(std::move(__x));
+	// else caller must move individual elements.
+      }
+# endif
+
+      // Used when allocator is_always_equal.
+      _List_base(_Node_alloc_type&& __a, _List_base&& __x)
+      : _M_impl(std::move(__a), std::move(__x._M_impl))
+      { }
+
+      // Used when allocator !is_always_equal.
+      _List_base(_Node_alloc_type&& __a)
+      : _M_impl(std::move(__a))
+      { }
+
+      void
+      _M_move_nodes(_List_base&& __x)
+      { _M_impl._M_node._M_move_nodes(std::move(__x._M_impl._M_node)); }
+#endif
+
+      // This is what actually destroys the list.
+      ~_List_base() _GLIBCXX_NOEXCEPT
+      { _M_clear(); }
+
+      void
+      _M_clear() _GLIBCXX_NOEXCEPT;
+
+      void
+      _M_init() _GLIBCXX_NOEXCEPT
+      { this->_M_impl._M_node._M_init(); }
+    };
+
+  /**
+   *  @brief A standard container with linear time access to elements,
+   *  and fixed time insertion/deletion at any point in the sequence.
+   *
+   *  @ingroup sequences
+   *
+   *  @tparam _Tp  Type of element.
+   *  @tparam _Alloc  Allocator type, defaults to allocator<_Tp>.
+   *
+   *  Meets the requirements of a <a href="tables.html#65">container</a>, a
+   *  <a href="tables.html#66">reversible container</a>, and a
+   *  <a href="tables.html#67">sequence</a>, including the
+   *  <a href="tables.html#68">optional sequence requirements</a> with the
+   *  %exception of @c at and @c operator[].
+   *
+   *  This is a @e doubly @e linked %list.  Traversal up and down the
+   *  %list requires linear time, but adding and removing elements (or
+   *  @e nodes) is done in constant time, regardless of where the
+   *  change takes place.  Unlike std::vector and std::deque,
+   *  random-access iterators are not provided, so subscripting ( @c
+   *  [] ) access is not allowed.  For algorithms which only need
+   *  sequential access, this lack makes no difference.
+   *
+   *  Also unlike the other standard containers, std::list provides
+   *  specialized algorithms %unique to linked lists, such as
+   *  splicing, sorting, and in-place reversal.
+   *
+   *  A couple points on memory allocation for list<Tp>:
+   *
+   *  First, we never actually allocate a Tp, we allocate
+   *  List_node<Tp>'s and trust [20.1.5]/4 to DTRT.  This is to ensure
+   *  that after elements from %list<X,Alloc1> are spliced into
+   *  %list<X,Alloc2>, destroying the memory of the second %list is a
+   *  valid operation, i.e., Alloc1 giveth and Alloc2 taketh away.
+   *
+   *  Second, a %list conceptually represented as
+   *  @code
+   *    A <---> B <---> C <---> D
+   *  @endcode
+   *  is actually circular; a link exists between A and D.  The %list
+   *  class holds (as its only data member) a private list::iterator
+   *  pointing to @e D, not to @e A!  To get to the head of the %list,
+   *  we start at the tail and move forward by one.  When this member
+   *  iterator's next/previous pointers refer to itself, the %list is
+   *  %empty.
+  */
+  template<typename _Tp, typename _Alloc = std::allocator<_Tp> >
+    class list : protected _List_base<_Tp, _Alloc>
+    {
+#ifdef _GLIBCXX_CONCEPT_CHECKS
+      // concept requirements
+      typedef typename _Alloc::value_type		_Alloc_value_type;
+# if __cplusplus < 201103L
+      __glibcxx_class_requires(_Tp, _SGIAssignableConcept)
+# endif
+      __glibcxx_class_requires2(_Tp, _Alloc_value_type, _SameTypeConcept)
+#endif
+
+#if __cplusplus >= 201103L
+      static_assert(is_same<typename remove_cv<_Tp>::type, _Tp>::value,
+	  "std::list must have a non-const, non-volatile value_type");
+# if __cplusplus > 201703L || defined __STRICT_ANSI__
+      static_assert(is_same<typename _Alloc::value_type, _Tp>::value,
+	  "std::list must have the same value_type as its allocator");
+# endif
+#endif
+
+      typedef _List_base<_Tp, _Alloc>			_Base;
+      typedef typename _Base::_Tp_alloc_type		_Tp_alloc_type;
+      typedef typename _Base::_Tp_alloc_traits		_Tp_alloc_traits;
+      typedef typename _Base::_Node_alloc_type		_Node_alloc_type;
+      typedef typename _Base::_Node_alloc_traits	_Node_alloc_traits;
+
+    public:
+      typedef _Tp					 value_type;
+      typedef typename _Tp_alloc_traits::pointer	 pointer;
+      typedef typename _Tp_alloc_traits::const_pointer	 const_pointer;
+      typedef typename _Tp_alloc_traits::reference	 reference;
+      typedef typename _Tp_alloc_traits::const_reference const_reference;
+      typedef _List_iterator<_Tp>			 iterator;
+      typedef _List_const_iterator<_Tp>			 const_iterator;
+      typedef std::reverse_iterator<const_iterator>	 const_reverse_iterator;
+      typedef std::reverse_iterator<iterator>		 reverse_iterator;
+      typedef size_t					 size_type;
+      typedef ptrdiff_t					 difference_type;
+      typedef _Alloc					 allocator_type;
+
+    protected:
+      // Note that pointers-to-_Node's can be ctor-converted to
+      // iterator types.
+      typedef _List_node<_Tp>				 _Node;
+
+      using _Base::_M_impl;
+      using _Base::_M_put_node;
+      using _Base::_M_get_node;
+      using _Base::_M_get_Node_allocator;
+
+      /**
+       *  @param  __args  An instance of user data.
+       *
+       *  Allocates space for a new node and constructs a copy of
+       *  @a __args in it.
+       */
+#if __cplusplus < 201103L
+      _Node*
+      _M_create_node(const value_type& __x)
+      {
+	_Node* __p = this->_M_get_node();
+	__try
+	  {
+	    _Tp_alloc_type __alloc(_M_get_Node_allocator());
+	    __alloc.construct(__p->_M_valptr(), __x);
+	  }
+	__catch(...)
+	  {
+	    _M_put_node(__p);
+	    __throw_exception_again;
+	  }
+	return __p;
+      }
+#else
+      template<typename... _Args>
+	_Node*
+	_M_create_node(_Args&&... __args)
+	{
+	  auto __p = this->_M_get_node();
+	  auto& __alloc = _M_get_Node_allocator();
+	  __allocated_ptr<_Node_alloc_type> __guard{__alloc, __p};
+	  _Node_alloc_traits::construct(__alloc, __p->_M_valptr(),
+					std::forward<_Args>(__args)...);
+	  __guard = nullptr;
+	  return __p;
+	}
+#endif
+
+#if _GLIBCXX_USE_CXX11_ABI
+      static size_t
+      _S_distance(const_iterator __first, const_iterator __last)
+      { return std::distance(__first, __last); }
+
+      // return the stored size
+      size_t
+      _M_node_count() const
+      { return this->_M_get_size(); }
+#else
+      // dummy implementations used when the size is not stored
+      static size_t
+      _S_distance(const_iterator, const_iterator)
+      { return 0; }
+
+      // count the number of nodes
+      size_t
+      _M_node_count() const
+      { return std::distance(begin(), end()); }
+#endif
+
+    public:
+      // [23.2.2.1] construct/copy/destroy
+      // (assign() and get_allocator() are also listed in this section)
+
+      /**
+       *  @brief  Creates a %list with no elements.
+       */
+#if __cplusplus >= 201103L
+      list() = default;
+#else
+      list() { }
+#endif
+
+      /**
+       *  @brief  Creates a %list with no elements.
+       *  @param  __a  An allocator object.
+       */
+      explicit
+      list(const allocator_type& __a) _GLIBCXX_NOEXCEPT
+      : _Base(_Node_alloc_type(__a)) { }
+
+#if __cplusplus >= 201103L
+      /**
+       *  @brief  Creates a %list with default constructed elements.
+       *  @param  __n  The number of elements to initially create.
+       *  @param  __a  An allocator object.
+       *
+       *  This constructor fills the %list with @a __n default
+       *  constructed elements.
+       */
+      explicit
+      list(size_type __n, const allocator_type& __a = allocator_type())
+      : _Base(_Node_alloc_type(__a))
+      { _M_default_initialize(__n); }
+
+      /**
+       *  @brief  Creates a %list with copies of an exemplar element.
+       *  @param  __n  The number of elements to initially create.
+       *  @param  __value  An element to copy.
+       *  @param  __a  An allocator object.
+       *
+       *  This constructor fills the %list with @a __n copies of @a __value.
+       */
+      list(size_type __n, const value_type& __value,
+	   const allocator_type& __a = allocator_type())
+      : _Base(_Node_alloc_type(__a))
+      { _M_fill_initialize(__n, __value); }
+#else
+      /**
+       *  @brief  Creates a %list with copies of an exemplar element.
+       *  @param  __n  The number of elements to initially create.
+       *  @param  __value  An element to copy.
+       *  @param  __a  An allocator object.
+       *
+       *  This constructor fills the %list with @a __n copies of @a __value.
+       */
+      explicit
+      list(size_type __n, const value_type& __value = value_type(),
+	   const allocator_type& __a = allocator_type())
+      : _Base(_Node_alloc_type(__a))
+      { _M_fill_initialize(__n, __value); }
+#endif
+
+      /**
+       *  @brief  %List copy constructor.
+       *  @param  __x  A %list of identical element and allocator types.
+       *
+       *  The newly-created %list uses a copy of the allocation object used
+       *  by @a __x (unless the allocator traits dictate a different object).
+       */
+      list(const list& __x)
+      : _Base(_Node_alloc_traits::
+	      _S_select_on_copy(__x._M_get_Node_allocator()))
+      { _M_initialize_dispatch(__x.begin(), __x.end(), __false_type()); }
+
+#if __cplusplus >= 201103L
+      /**
+       *  @brief  %List move constructor.
+       *
+       *  The newly-created %list contains the exact contents of the moved
+       *  instance. The contents of the moved instance are a valid, but
+       *  unspecified %list.
+       */
+      list(list&&) = default;
+
+      /**
+       *  @brief  Builds a %list from an initializer_list
+       *  @param  __l  An initializer_list of value_type.
+       *  @param  __a  An allocator object.
+       *
+       *  Create a %list consisting of copies of the elements in the
+       *  initializer_list @a __l.  This is linear in __l.size().
+       */
+      list(initializer_list<value_type> __l,
+	   const allocator_type& __a = allocator_type())
+      : _Base(_Node_alloc_type(__a))
+      { _M_initialize_dispatch(__l.begin(), __l.end(), __false_type()); }
+
+      list(const list& __x, const __type_identity_t<allocator_type>& __a)
+      : _Base(_Node_alloc_type(__a))
+      { _M_initialize_dispatch(__x.begin(), __x.end(), __false_type()); }
+
+    private:
+      list(list&& __x, const allocator_type& __a, true_type) noexcept
+      : _Base(_Node_alloc_type(__a), std::move(__x))
+      { }
+
+      list(list&& __x, const allocator_type& __a, false_type)
+      : _Base(_Node_alloc_type(__a))
+      {
+	if (__x._M_get_Node_allocator() == this->_M_get_Node_allocator())
+	  this->_M_move_nodes(std::move(__x));
+	else
+	  insert(begin(), std::__make_move_if_noexcept_iterator(__x.begin()),
+			  std::__make_move_if_noexcept_iterator(__x.end()));
+      }
+
+    public:
+      list(list&& __x, const __type_identity_t<allocator_type>& __a)
+      noexcept(_Node_alloc_traits::_S_always_equal())
+      : list(std::move(__x), __a,
+	     typename _Node_alloc_traits::is_always_equal{})
+      { }
+#endif
+
+      /**
+       *  @brief  Builds a %list from a range.
+       *  @param  __first  An input iterator.
+       *  @param  __last  An input iterator.
+       *  @param  __a  An allocator object.
+       *
+       *  Create a %list consisting of copies of the elements from
+       *  [@a __first,@a __last).  This is linear in N (where N is
+       *  distance(@a __first,@a __last)).
+       */
+#if __cplusplus >= 201103L
+      template<typename _InputIterator,
+	       typename = std::_RequireInputIter<_InputIterator>>
+	list(_InputIterator __first, _InputIterator __last,
+	     const allocator_type& __a = allocator_type())
+	: _Base(_Node_alloc_type(__a))
+	{ _M_initialize_dispatch(__first, __last, __false_type()); }
+#else
+      template<typename _InputIterator>
+	list(_InputIterator __first, _InputIterator __last,
+	     const allocator_type& __a = allocator_type())
+	: _Base(_Node_alloc_type(__a))
+	{
+	  // Check whether it's an integral type.  If so, it's not an iterator.
+	  typedef typename std::__is_integer<_InputIterator>::__type _Integral;
+	  _M_initialize_dispatch(__first, __last, _Integral());
+	}
+#endif
+
+#if __cplusplus >= 201103L
+      /**
+       *  No explicit dtor needed as the _Base dtor takes care of
+       *  things.  The _Base dtor only erases the elements, and note
+       *  that if the elements themselves are pointers, the pointed-to
+       *  memory is not touched in any way.  Managing the pointer is
+       *  the user's responsibility.
+       */
+      ~list() = default;
+#endif
+
+      /**
+       *  @brief  %List assignment operator.
+       *  @param  __x  A %list of identical element and allocator types.
+       *
+       *  All the elements of @a __x are copied.
+       *
+       *  Whether the allocator is copied depends on the allocator traits.
+       */
+      list&
+      operator=(const list& __x);
+
+#if __cplusplus >= 201103L
+      /**
+       *  @brief  %List move assignment operator.
+       *  @param  __x  A %list of identical element and allocator types.
+       *
+       *  The contents of @a __x are moved into this %list (without copying).
+       *
+       *  Afterwards @a __x is a valid, but unspecified %list
+       *
+       *  Whether the allocator is moved depends on the allocator traits.
+       */
+      list&
+      operator=(list&& __x)
+      noexcept(_Node_alloc_traits::_S_nothrow_move())
+      {
+	constexpr bool __move_storage =
+	  _Node_alloc_traits::_S_propagate_on_move_assign()
+	  || _Node_alloc_traits::_S_always_equal();
+	_M_move_assign(std::move(__x), __bool_constant<__move_storage>());
+	return *this;
+      }
+
+      /**
+       *  @brief  %List initializer list assignment operator.
+       *  @param  __l  An initializer_list of value_type.
+       *
+       *  Replace the contents of the %list with copies of the elements
+       *  in the initializer_list @a __l.  This is linear in l.size().
+       */
+      list&
+      operator=(initializer_list<value_type> __l)
+      {
+	this->assign(__l.begin(), __l.end());
+	return *this;
+      }
+#endif
+
+      /**
+       *  @brief  Assigns a given value to a %list.
+       *  @param  __n  Number of elements to be assigned.
+       *  @param  __val  Value to be assigned.
+       *
+       *  This function fills a %list with @a __n copies of the given
+       *  value.  Note that the assignment completely changes the %list
+       *  and that the resulting %list's size is the same as the number
+       *  of elements assigned.
+       */
+      void
+      assign(size_type __n, const value_type& __val)
+      { _M_fill_assign(__n, __val); }
+
+      /**
+       *  @brief  Assigns a range to a %list.
+       *  @param  __first  An input iterator.
+       *  @param  __last   An input iterator.
+       *
+       *  This function fills a %list with copies of the elements in the
+       *  range [@a __first,@a __last).
+       *
+       *  Note that the assignment completely changes the %list and
+       *  that the resulting %list's size is the same as the number of
+       *  elements assigned.
+       */
+#if __cplusplus >= 201103L
+      template<typename _InputIterator,
+	       typename = std::_RequireInputIter<_InputIterator>>
+	void
+	assign(_InputIterator __first, _InputIterator __last)
+	{ _M_assign_dispatch(__first, __last, __false_type()); }
+#else
+      template<typename _InputIterator>
+	void
+	assign(_InputIterator __first, _InputIterator __last)
+	{
+	  // Check whether it's an integral type.  If so, it's not an iterator.
+	  typedef typename std::__is_integer<_InputIterator>::__type _Integral;
+	  _M_assign_dispatch(__first, __last, _Integral());
+	}
+#endif
+
+#if __cplusplus >= 201103L
+      /**
+       *  @brief  Assigns an initializer_list to a %list.
+       *  @param  __l  An initializer_list of value_type.
+       *
+       *  Replace the contents of the %list with copies of the elements
+       *  in the initializer_list @a __l.  This is linear in __l.size().
+       */
+      void
+      assign(initializer_list<value_type> __l)
+      { this->_M_assign_dispatch(__l.begin(), __l.end(), __false_type()); }
+#endif
+
+      /// Get a copy of the memory allocation object.
+      allocator_type
+      get_allocator() const _GLIBCXX_NOEXCEPT
+      { return allocator_type(_Base::_M_get_Node_allocator()); }
+
+      // iterators
+      /**
+       *  Returns a read/write iterator that points to the first element in the
+       *  %list.  Iteration is done in ordinary element order.
+       */
+      _GLIBCXX_NODISCARD
+      iterator
+      begin() _GLIBCXX_NOEXCEPT
+      { return iterator(this->_M_impl._M_node._M_next); }
+
+      /**
+       *  Returns a read-only (constant) iterator that points to the
+       *  first element in the %list.  Iteration is done in ordinary
+       *  element order.
+       */
+      _GLIBCXX_NODISCARD
+      const_iterator
+      begin() const _GLIBCXX_NOEXCEPT
+      { return const_iterator(this->_M_impl._M_node._M_next); }
+
+      /**
+       *  Returns a read/write iterator that points one past the last
+       *  element in the %list.  Iteration is done in ordinary element
+       *  order.
+       */
+      _GLIBCXX_NODISCARD
+      iterator
+      end() _GLIBCXX_NOEXCEPT
+      { return iterator(&this->_M_impl._M_node); }
+
+      /**
+       *  Returns a read-only (constant) iterator that points one past
+       *  the last element in the %list.  Iteration is done in ordinary
+       *  element order.
+       */
+      _GLIBCXX_NODISCARD
+      const_iterator
+      end() const _GLIBCXX_NOEXCEPT
+      { return const_iterator(&this->_M_impl._M_node); }
+
+      /**
+       *  Returns a read/write reverse iterator that points to the last
+       *  element in the %list.  Iteration is done in reverse element
+       *  order.
+       */
+      _GLIBCXX_NODISCARD
+      reverse_iterator
+      rbegin() _GLIBCXX_NOEXCEPT
+      { return reverse_iterator(end()); }
+
+      /**
+       *  Returns a read-only (constant) reverse iterator that points to
+       *  the last element in the %list.  Iteration is done in reverse
+       *  element order.
+       */
+      _GLIBCXX_NODISCARD
+      const_reverse_iterator
+      rbegin() const _GLIBCXX_NOEXCEPT
+      { return const_reverse_iterator(end()); }
+
+      /**
+       *  Returns a read/write reverse iterator that points to one
+       *  before the first element in the %list.  Iteration is done in
+       *  reverse element order.
+       */
+      _GLIBCXX_NODISCARD
+      reverse_iterator
+      rend() _GLIBCXX_NOEXCEPT
+      { return reverse_iterator(begin()); }
+
+      /**
+       *  Returns a read-only (constant) reverse iterator that points to one
+       *  before the first element in the %list.  Iteration is done in reverse
+       *  element order.
+       */
+      _GLIBCXX_NODISCARD
+      const_reverse_iterator
+      rend() const _GLIBCXX_NOEXCEPT
+      { return const_reverse_iterator(begin()); }
+
+#if __cplusplus >= 201103L
+      /**
+       *  Returns a read-only (constant) iterator that points to the
+       *  first element in the %list.  Iteration is done in ordinary
+       *  element order.
+       */
+      [[__nodiscard__]]
+      const_iterator
+      cbegin() const noexcept
+      { return const_iterator(this->_M_impl._M_node._M_next); }
+
+      /**
+       *  Returns a read-only (constant) iterator that points one past
+       *  the last element in the %list.  Iteration is done in ordinary
+       *  element order.
+       */
+      [[__nodiscard__]]
+      const_iterator
+      cend() const noexcept
+      { return const_iterator(&this->_M_impl._M_node); }
+
+      /**
+       *  Returns a read-only (constant) reverse iterator that points to
+       *  the last element in the %list.  Iteration is done in reverse
+       *  element order.
+       */
+      [[__nodiscard__]]
+      const_reverse_iterator
+      crbegin() const noexcept
+      { return const_reverse_iterator(end()); }
+
+      /**
+       *  Returns a read-only (constant) reverse iterator that points to one
+       *  before the first element in the %list.  Iteration is done in reverse
+       *  element order.
+       */
+      [[__nodiscard__]]
+      const_reverse_iterator
+      crend() const noexcept
+      { return const_reverse_iterator(begin()); }
+#endif
+
+      // [23.2.2.2] capacity
+      /**
+       *  Returns true if the %list is empty.  (Thus begin() would equal
+       *  end().)
+       */
+      _GLIBCXX_NODISCARD bool
+      empty() const _GLIBCXX_NOEXCEPT
+      { return this->_M_impl._M_node._M_next == &this->_M_impl._M_node; }
+
+      /**  Returns the number of elements in the %list.  */
+      _GLIBCXX_NODISCARD
+      size_type
+      size() const _GLIBCXX_NOEXCEPT
+      { return _M_node_count(); }
+
+      /**  Returns the size() of the largest possible %list.  */
+      _GLIBCXX_NODISCARD
+      size_type
+      max_size() const _GLIBCXX_NOEXCEPT
+      { return _Node_alloc_traits::max_size(_M_get_Node_allocator()); }
+
+#if __cplusplus >= 201103L
+      /**
+       *  @brief Resizes the %list to the specified number of elements.
+       *  @param __new_size Number of elements the %list should contain.
+       *
+       *  This function will %resize the %list to the specified number
+       *  of elements.  If the number is smaller than the %list's
+       *  current size the %list is truncated, otherwise default
+       *  constructed elements are appended.
+       */
+      void
+      resize(size_type __new_size);
+
+      /**
+       *  @brief Resizes the %list to the specified number of elements.
+       *  @param __new_size Number of elements the %list should contain.
+       *  @param __x Data with which new elements should be populated.
+       *
+       *  This function will %resize the %list to the specified number
+       *  of elements.  If the number is smaller than the %list's
+       *  current size the %list is truncated, otherwise the %list is
+       *  extended and new elements are populated with given data.
+       */
+      void
+      resize(size_type __new_size, const value_type& __x);
+#else
+      /**
+       *  @brief Resizes the %list to the specified number of elements.
+       *  @param __new_size Number of elements the %list should contain.
+       *  @param __x Data with which new elements should be populated.
+       *
+       *  This function will %resize the %list to the specified number
+       *  of elements.  If the number is smaller than the %list's
+       *  current size the %list is truncated, otherwise the %list is
+       *  extended and new elements are populated with given data.
+       */
+      void
+      resize(size_type __new_size, value_type __x = value_type());
+#endif
+
+      // element access
+      /**
+       *  Returns a read/write reference to the data at the first
+       *  element of the %list.
+       */
+      _GLIBCXX_NODISCARD
+      reference
+      front() _GLIBCXX_NOEXCEPT
+      { return *begin(); }
+
+      /**
+       *  Returns a read-only (constant) reference to the data at the first
+       *  element of the %list.
+       */
+      _GLIBCXX_NODISCARD
+      const_reference
+      front() const _GLIBCXX_NOEXCEPT
+      { return *begin(); }
+
+      /**
+       *  Returns a read/write reference to the data at the last element
+       *  of the %list.
+       */
+      _GLIBCXX_NODISCARD
+      reference
+      back() _GLIBCXX_NOEXCEPT
+      {
+	iterator __tmp = end();
+	--__tmp;
+	return *__tmp;
+      }
+
+      /**
+       *  Returns a read-only (constant) reference to the data at the last
+       *  element of the %list.
+       */
+      _GLIBCXX_NODISCARD
+      const_reference
+      back() const _GLIBCXX_NOEXCEPT
+      {
+	const_iterator __tmp = end();
+	--__tmp;
+	return *__tmp;
+      }
+
+      // [23.2.2.3] modifiers
+      /**
+       *  @brief  Add data to the front of the %list.
+       *  @param  __x  Data to be added.
+       *
+       *  This is a typical stack operation.  The function creates an
+       *  element at the front of the %list and assigns the given data
+       *  to it.  Due to the nature of a %list this operation can be
+       *  done in constant time, and does not invalidate iterators and
+       *  references.
+       */
+      void
+      push_front(const value_type& __x)
+      { this->_M_insert(begin(), __x); }
+
+#if __cplusplus >= 201103L
+      void
+      push_front(value_type&& __x)
+      { this->_M_insert(begin(), std::move(__x)); }
+
+      template<typename... _Args>
+#if __cplusplus > 201402L
+	reference
+#else
+	void
+#endif
+	emplace_front(_Args&&... __args)
+	{
+	  this->_M_insert(begin(), std::forward<_Args>(__args)...);
+#if __cplusplus > 201402L
+	  return front();
+#endif
+	}
+#endif
+
+      /**
+       *  @brief  Removes first element.
+       *
+       *  This is a typical stack operation.  It shrinks the %list by
+       *  one.  Due to the nature of a %list this operation can be done
+       *  in constant time, and only invalidates iterators/references to
+       *  the element being removed.
+       *
+       *  Note that no data is returned, and if the first element's data
+       *  is needed, it should be retrieved before pop_front() is
+       *  called.
+       */
+      void
+      pop_front() _GLIBCXX_NOEXCEPT
+      { this->_M_erase(begin()); }
+
+      /**
+       *  @brief  Add data to the end of the %list.
+       *  @param  __x  Data to be added.
+       *
+       *  This is a typical stack operation.  The function creates an
+       *  element at the end of the %list and assigns the given data to
+       *  it.  Due to the nature of a %list this operation can be done
+       *  in constant time, and does not invalidate iterators and
+       *  references.
+       */
+      void
+      push_back(const value_type& __x)
+      { this->_M_insert(end(), __x); }
+
+#if __cplusplus >= 201103L
+      void
+      push_back(value_type&& __x)
+      { this->_M_insert(end(), std::move(__x)); }
+
+      template<typename... _Args>
+#if __cplusplus > 201402L
+	reference
+#else
+	void
+#endif
+	emplace_back(_Args&&... __args)
+	{
+	  this->_M_insert(end(), std::forward<_Args>(__args)...);
+#if __cplusplus > 201402L
+	return back();
+#endif
+	}
+#endif
+
+      /**
+       *  @brief  Removes last element.
+       *
+       *  This is a typical stack operation.  It shrinks the %list by
+       *  one.  Due to the nature of a %list this operation can be done
+       *  in constant time, and only invalidates iterators/references to
+       *  the element being removed.
+       *
+       *  Note that no data is returned, and if the last element's data
+       *  is needed, it should be retrieved before pop_back() is called.
+       */
+      void
+      pop_back() _GLIBCXX_NOEXCEPT
+      { this->_M_erase(iterator(this->_M_impl._M_node._M_prev)); }
+
+#if __cplusplus >= 201103L
+      /**
+       *  @brief  Constructs object in %list before specified iterator.
+       *  @param  __position  A const_iterator into the %list.
+       *  @param  __args  Arguments.
+       *  @return  An iterator that points to the inserted data.
+       *
+       *  This function will insert an object of type T constructed
+       *  with T(std::forward<Args>(args)...) before the specified
+       *  location.  Due to the nature of a %list this operation can
+       *  be done in constant time, and does not invalidate iterators
+       *  and references.
+       */
+      template<typename... _Args>
+	iterator
+	emplace(const_iterator __position, _Args&&... __args);
+
+      /**
+       *  @brief  Inserts given value into %list before specified iterator.
+       *  @param  __position  A const_iterator into the %list.
+       *  @param  __x  Data to be inserted.
+       *  @return  An iterator that points to the inserted data.
+       *
+       *  This function will insert a copy of the given value before
+       *  the specified location.  Due to the nature of a %list this
+       *  operation can be done in constant time, and does not
+       *  invalidate iterators and references.
+       */
+      iterator
+      insert(const_iterator __position, const value_type& __x);
+#else
+      /**
+       *  @brief  Inserts given value into %list before specified iterator.
+       *  @param  __position  An iterator into the %list.
+       *  @param  __x  Data to be inserted.
+       *  @return  An iterator that points to the inserted data.
+       *
+       *  This function will insert a copy of the given value before
+       *  the specified location.  Due to the nature of a %list this
+       *  operation can be done in constant time, and does not
+       *  invalidate iterators and references.
+       */
+      iterator
+      insert(iterator __position, const value_type& __x);
+#endif
+
+#if __cplusplus >= 201103L
+      /**
+       *  @brief  Inserts given rvalue into %list before specified iterator.
+       *  @param  __position  A const_iterator into the %list.
+       *  @param  __x  Data to be inserted.
+       *  @return  An iterator that points to the inserted data.
+       *
+       *  This function will insert a copy of the given rvalue before
+       *  the specified location.  Due to the nature of a %list this
+       *  operation can be done in constant time, and does not
+       *  invalidate iterators and references.
+	*/
+      iterator
+      insert(const_iterator __position, value_type&& __x)
+      { return emplace(__position, std::move(__x)); }
+
+      /**
+       *  @brief  Inserts the contents of an initializer_list into %list
+       *          before specified const_iterator.
+       *  @param  __p  A const_iterator into the %list.
+       *  @param  __l  An initializer_list of value_type.
+       *  @return  An iterator pointing to the first element inserted
+       *           (or __position).
+       *
+       *  This function will insert copies of the data in the
+       *  initializer_list @a l into the %list before the location
+       *  specified by @a p.
+       *
+       *  This operation is linear in the number of elements inserted and
+       *  does not invalidate iterators and references.
+       */
+      iterator
+      insert(const_iterator __p, initializer_list<value_type> __l)
+      { return this->insert(__p, __l.begin(), __l.end()); }
+#endif
+
+#if __cplusplus >= 201103L
+      /**
+       *  @brief  Inserts a number of copies of given data into the %list.
+       *  @param  __position  A const_iterator into the %list.
+       *  @param  __n  Number of elements to be inserted.
+       *  @param  __x  Data to be inserted.
+       *  @return  An iterator pointing to the first element inserted
+       *           (or __position).
+       *
+       *  This function will insert a specified number of copies of the
+       *  given data before the location specified by @a position.
+       *
+       *  This operation is linear in the number of elements inserted and
+       *  does not invalidate iterators and references.
+       */
+      iterator
+      insert(const_iterator __position, size_type __n, const value_type& __x);
+#else
+      /**
+       *  @brief  Inserts a number of copies of given data into the %list.
+       *  @param  __position  An iterator into the %list.
+       *  @param  __n  Number of elements to be inserted.
+       *  @param  __x  Data to be inserted.
+       *
+       *  This function will insert a specified number of copies of the
+       *  given data before the location specified by @a position.
+       *
+       *  This operation is linear in the number of elements inserted and
+       *  does not invalidate iterators and references.
+       */
+      void
+      insert(iterator __position, size_type __n, const value_type& __x)
+      {
+	list __tmp(__n, __x, get_allocator());
+	splice(__position, __tmp);
+      }
+#endif
+
+#if __cplusplus >= 201103L
+      /**
+       *  @brief  Inserts a range into the %list.
+       *  @param  __position  A const_iterator into the %list.
+       *  @param  __first  An input iterator.
+       *  @param  __last   An input iterator.
+       *  @return  An iterator pointing to the first element inserted
+       *           (or __position).
+       *
+       *  This function will insert copies of the data in the range [@a
+       *  first,@a last) into the %list before the location specified by
+       *  @a position.
+       *
+       *  This operation is linear in the number of elements inserted and
+       *  does not invalidate iterators and references.
+       */
+      template<typename _InputIterator,
+	       typename = std::_RequireInputIter<_InputIterator>>
+	iterator
+	insert(const_iterator __position, _InputIterator __first,
+	       _InputIterator __last);
+#else
+      /**
+       *  @brief  Inserts a range into the %list.
+       *  @param  __position  An iterator into the %list.
+       *  @param  __first  An input iterator.
+       *  @param  __last   An input iterator.
+       *
+       *  This function will insert copies of the data in the range [@a
+       *  first,@a last) into the %list before the location specified by
+       *  @a position.
+       *
+       *  This operation is linear in the number of elements inserted and
+       *  does not invalidate iterators and references.
+       */
+      template<typename _InputIterator>
+	void
+	insert(iterator __position, _InputIterator __first,
+	       _InputIterator __last)
+	{
+	  list __tmp(__first, __last, get_allocator());
+	  splice(__position, __tmp);
+	}
+#endif
+
+      /**
+       *  @brief  Remove element at given position.
+       *  @param  __position  Iterator pointing to element to be erased.
+       *  @return  An iterator pointing to the next element (or end()).
+       *
+       *  This function will erase the element at the given position and thus
+       *  shorten the %list by one.
+       *
+       *  Due to the nature of a %list this operation can be done in
+       *  constant time, and only invalidates iterators/references to
+       *  the element being removed.  The user is also cautioned that
+       *  this function only erases the element, and that if the element
+       *  is itself a pointer, the pointed-to memory is not touched in
+       *  any way.  Managing the pointer is the user's responsibility.
+       */
+      iterator
+#if __cplusplus >= 201103L
+      erase(const_iterator __position) noexcept;
+#else
+      erase(iterator __position);
+#endif
+
+      /**
+       *  @brief  Remove a range of elements.
+       *  @param  __first  Iterator pointing to the first element to be erased.
+       *  @param  __last  Iterator pointing to one past the last element to be
+       *                erased.
+       *  @return  An iterator pointing to the element pointed to by @a last
+       *           prior to erasing (or end()).
+       *
+       *  This function will erase the elements in the range @a
+       *  [first,last) and shorten the %list accordingly.
+       *
+       *  This operation is linear time in the size of the range and only
+       *  invalidates iterators/references to the element being removed.
+       *  The user is also cautioned that this function only erases the
+       *  elements, and that if the elements themselves are pointers, the
+       *  pointed-to memory is not touched in any way.  Managing the pointer
+       *  is the user's responsibility.
+       */
+      iterator
+#if __cplusplus >= 201103L
+      erase(const_iterator __first, const_iterator __last) noexcept
+#else
+      erase(iterator __first, iterator __last)
+#endif
+      {
+	while (__first != __last)
+	  __first = erase(__first);
+	return __last._M_const_cast();
+      }
+
+      /**
+       *  @brief  Swaps data with another %list.
+       *  @param  __x  A %list of the same element and allocator types.
+       *
+       *  This exchanges the elements between two lists in constant
+       *  time.  Note that the global std::swap() function is
+       *  specialized such that std::swap(l1,l2) will feed to this
+       *  function.
+       *
+       *  Whether the allocators are swapped depends on the allocator traits.
+       */
+      void
+      swap(list& __x) _GLIBCXX_NOEXCEPT
+      {
+	__detail::_List_node_base::swap(this->_M_impl._M_node,
+					__x._M_impl._M_node);
+
+	size_t __xsize = __x._M_get_size();
+	__x._M_set_size(this->_M_get_size());
+	this->_M_set_size(__xsize);
+
+	_Node_alloc_traits::_S_on_swap(this->_M_get_Node_allocator(),
+				       __x._M_get_Node_allocator());
+      }
+
+      /**
+       *  Erases all the elements.  Note that this function only erases
+       *  the elements, and that if the elements themselves are
+       *  pointers, the pointed-to memory is not touched in any way.
+       *  Managing the pointer is the user's responsibility.
+       */
+      void
+      clear() _GLIBCXX_NOEXCEPT
+      {
+	_Base::_M_clear();
+	_Base::_M_init();
+      }
+
+      // [23.2.2.4] list operations
+      /**
+       *  @brief  Insert contents of another %list.
+       *  @param  __position  Iterator referencing the element to insert before.
+       *  @param  __x  Source list.
+       *
+       *  The elements of @a __x are inserted in constant time in front of
+       *  the element referenced by @a __position.  @a __x becomes an empty
+       *  list.
+       *
+       *  Requires this != @a __x.
+       */
+      void
+#if __cplusplus >= 201103L
+      splice(const_iterator __position, list&& __x) noexcept
+#else
+      splice(iterator __position, list& __x)
+#endif
+      {
+	if (!__x.empty())
+	  {
+	    _M_check_equal_allocators(__x);
+
+	    this->_M_transfer(__position._M_const_cast(),
+			      __x.begin(), __x.end());
+
+	    this->_M_inc_size(__x._M_get_size());
+	    __x._M_set_size(0);
+	  }
+      }
+
+#if __cplusplus >= 201103L
+      void
+      splice(const_iterator __position, list& __x) noexcept
+      { splice(__position, std::move(__x)); }
+#endif
+
+#if __cplusplus >= 201103L
+      /**
+       *  @brief  Insert element from another %list.
+       *  @param  __position  Const_iterator referencing the element to
+       *                      insert before.
+       *  @param  __x  Source list.
+       *  @param  __i  Const_iterator referencing the element to move.
+       *
+       *  Removes the element in list @a __x referenced by @a __i and
+       *  inserts it into the current list before @a __position.
+       */
+      void
+      splice(const_iterator __position, list&& __x, const_iterator __i) noexcept
+#else
+      /**
+       *  @brief  Insert element from another %list.
+       *  @param  __position  Iterator referencing the element to insert before.
+       *  @param  __x  Source list.
+       *  @param  __i  Iterator referencing the element to move.
+       *
+       *  Removes the element in list @a __x referenced by @a __i and
+       *  inserts it into the current list before @a __position.
+       */
+      void
+      splice(iterator __position, list& __x, iterator __i)
+#endif
+      {
+	iterator __j = __i._M_const_cast();
+	++__j;
+	if (__position == __i || __position == __j)
+	  return;
+
+	if (this != std::__addressof(__x))
+	  _M_check_equal_allocators(__x);
+
+	this->_M_transfer(__position._M_const_cast(),
+			  __i._M_const_cast(), __j);
+
+	this->_M_inc_size(1);
+	__x._M_dec_size(1);
+      }
+
+#if __cplusplus >= 201103L
+      /**
+       *  @brief  Insert element from another %list.
+       *  @param  __position  Const_iterator referencing the element to
+       *                      insert before.
+       *  @param  __x  Source list.
+       *  @param  __i  Const_iterator referencing the element to move.
+       *
+       *  Removes the element in list @a __x referenced by @a __i and
+       *  inserts it into the current list before @a __position.
+       */
+      void
+      splice(const_iterator __position, list& __x, const_iterator __i) noexcept
+      { splice(__position, std::move(__x), __i); }
+#endif
+
+#if __cplusplus >= 201103L
+      /**
+       *  @brief  Insert range from another %list.
+       *  @param  __position  Const_iterator referencing the element to
+       *                      insert before.
+       *  @param  __x  Source list.
+       *  @param  __first  Const_iterator referencing the start of range in x.
+       *  @param  __last  Const_iterator referencing the end of range in x.
+       *
+       *  Removes elements in the range [__first,__last) and inserts them
+       *  before @a __position in constant time.
+       *
+       *  Undefined if @a __position is in [__first,__last).
+       */
+      void
+      splice(const_iterator __position, list&& __x, const_iterator __first,
+	     const_iterator __last) noexcept
+#else
+      /**
+       *  @brief  Insert range from another %list.
+       *  @param  __position  Iterator referencing the element to insert before.
+       *  @param  __x  Source list.
+       *  @param  __first  Iterator referencing the start of range in x.
+       *  @param  __last  Iterator referencing the end of range in x.
+       *
+       *  Removes elements in the range [__first,__last) and inserts them
+       *  before @a __position in constant time.
+       *
+       *  Undefined if @a __position is in [__first,__last).
+       */
+      void
+      splice(iterator __position, list& __x, iterator __first,
+	     iterator __last)
+#endif
+      {
+	if (__first != __last)
+	  {
+	    if (this != std::__addressof(__x))
+	      _M_check_equal_allocators(__x);
+
+	    size_t __n = _S_distance(__first, __last);
+	    this->_M_inc_size(__n);
+	    __x._M_dec_size(__n);
+
+	    this->_M_transfer(__position._M_const_cast(),
+			      __first._M_const_cast(),
+			      __last._M_const_cast());
+	  }
+      }
+
+#if __cplusplus >= 201103L
+      /**
+       *  @brief  Insert range from another %list.
+       *  @param  __position  Const_iterator referencing the element to
+       *                      insert before.
+       *  @param  __x  Source list.
+       *  @param  __first  Const_iterator referencing the start of range in x.
+       *  @param  __last  Const_iterator referencing the end of range in x.
+       *
+       *  Removes elements in the range [__first,__last) and inserts them
+       *  before @a __position in constant time.
+       *
+       *  Undefined if @a __position is in [__first,__last).
+       */
+      void
+      splice(const_iterator __position, list& __x, const_iterator __first,
+	     const_iterator __last) noexcept
+      { splice(__position, std::move(__x), __first, __last); }
+#endif
+
+    private:
+#if __cplusplus > 201703L
+# define __cpp_lib_list_remove_return_type 201806L
+      typedef size_type __remove_return_type;
+# define _GLIBCXX_LIST_REMOVE_RETURN_TYPE_TAG \
+      __attribute__((__abi_tag__("__cxx20")))
+#else
+      typedef void __remove_return_type;
+# define _GLIBCXX_LIST_REMOVE_RETURN_TYPE_TAG
+#endif
+    public:
+
+      /**
+       *  @brief  Remove all elements equal to value.
+       *  @param  __value  The value to remove.
+       *
+       *  Removes every element in the list equal to @a value.
+       *  Remaining elements stay in list order.  Note that this
+       *  function only erases the elements, and that if the elements
+       *  themselves are pointers, the pointed-to memory is not
+       *  touched in any way.  Managing the pointer is the user's
+       *  responsibility.
+       */
+      _GLIBCXX_LIST_REMOVE_RETURN_TYPE_TAG
+      __remove_return_type
+      remove(const _Tp& __value);
+
+      /**
+       *  @brief  Remove all elements satisfying a predicate.
+       *  @tparam  _Predicate  Unary predicate function or object.
+       *
+       *  Removes every element in the list for which the predicate
+       *  returns true.  Remaining elements stay in list order.  Note
+       *  that this function only erases the elements, and that if the
+       *  elements themselves are pointers, the pointed-to memory is
+       *  not touched in any way.  Managing the pointer is the user's
+       *  responsibility.
+       */
+      template<typename _Predicate>
+	__remove_return_type
+	remove_if(_Predicate);
+
+      /**
+       *  @brief  Remove consecutive duplicate elements.
+       *
+       *  For each consecutive set of elements with the same value,
+       *  remove all but the first one.  Remaining elements stay in
+       *  list order.  Note that this function only erases the
+       *  elements, and that if the elements themselves are pointers,
+       *  the pointed-to memory is not touched in any way.  Managing
+       *  the pointer is the user's responsibility.
+       */
+      _GLIBCXX_LIST_REMOVE_RETURN_TYPE_TAG
+      __remove_return_type
+      unique();
+
+      /**
+       *  @brief  Remove consecutive elements satisfying a predicate.
+       *  @tparam _BinaryPredicate  Binary predicate function or object.
+       *
+       *  For each consecutive set of elements [first,last) that
+       *  satisfy predicate(first,i) where i is an iterator in
+       *  [first,last), remove all but the first one.  Remaining
+       *  elements stay in list order.  Note that this function only
+       *  erases the elements, and that if the elements themselves are
+       *  pointers, the pointed-to memory is not touched in any way.
+       *  Managing the pointer is the user's responsibility.
+       */
+      template<typename _BinaryPredicate>
+	__remove_return_type
+	unique(_BinaryPredicate);
+
+#undef _GLIBCXX_LIST_REMOVE_RETURN_TYPE_TAG
+
+      /**
+       *  @brief  Merge sorted lists.
+       *  @param  __x  Sorted list to merge.
+       *
+       *  Assumes that both @a __x and this list are sorted according to
+       *  operator<().  Merges elements of @a __x into this list in
+       *  sorted order, leaving @a __x empty when complete.  Elements in
+       *  this list precede elements in @a __x that are equal.
+       */
+#if __cplusplus >= 201103L
+      void
+      merge(list&& __x);
+
+      void
+      merge(list& __x)
+      { merge(std::move(__x)); }
+#else
+      void
+      merge(list& __x);
+#endif
+
+      /**
+       *  @brief  Merge sorted lists according to comparison function.
+       *  @tparam _StrictWeakOrdering Comparison function defining
+       *  sort order.
+       *  @param  __x  Sorted list to merge.
+       *  @param  __comp  Comparison functor.
+       *
+       *  Assumes that both @a __x and this list are sorted according to
+       *  StrictWeakOrdering.  Merges elements of @a __x into this list
+       *  in sorted order, leaving @a __x empty when complete.  Elements
+       *  in this list precede elements in @a __x that are equivalent
+       *  according to StrictWeakOrdering().
+       */
+#if __cplusplus >= 201103L
+      template<typename _StrictWeakOrdering>
+	void
+	merge(list&& __x, _StrictWeakOrdering __comp);
+
+      template<typename _StrictWeakOrdering>
+	void
+	merge(list& __x, _StrictWeakOrdering __comp)
+	{ merge(std::move(__x), __comp); }
+#else
+      template<typename _StrictWeakOrdering>
+	void
+	merge(list& __x, _StrictWeakOrdering __comp);
+#endif
+
+      /**
+       *  @brief  Reverse the elements in list.
+       *
+       *  Reverse the order of elements in the list in linear time.
+       */
+      void
+      reverse() _GLIBCXX_NOEXCEPT
+      { this->_M_impl._M_node._M_reverse(); }
+
+      /**
+       *  @brief  Sort the elements.
+       *
+       *  Sorts the elements of this list in NlogN time.  Equivalent
+       *  elements remain in list order.
+       */
+      void
+      sort();
+
+      /**
+       *  @brief  Sort the elements according to comparison function.
+       *
+       *  Sorts the elements of this list in NlogN time.  Equivalent
+       *  elements remain in list order.
+       */
+      template<typename _StrictWeakOrdering>
+	void
+	sort(_StrictWeakOrdering);
+
+    protected:
+      // Internal constructor functions follow.
+
+      // Called by the range constructor to implement [23.1.1]/9
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 438. Ambiguity in the "do the right thing" clause
+      template<typename _Integer>
+	void
+	_M_initialize_dispatch(_Integer __n, _Integer __x, __true_type)
+	{ _M_fill_initialize(static_cast<size_type>(__n), __x); }
+
+      // Called by the range constructor to implement [23.1.1]/9
+      template<typename _InputIterator>
+	void
+	_M_initialize_dispatch(_InputIterator __first, _InputIterator __last,
+			       __false_type)
+	{
+	  for (; __first != __last; ++__first)
+#if __cplusplus >= 201103L
+	    emplace_back(*__first);
+#else
+	    push_back(*__first);
+#endif
+	}
+
+      // Called by list(n,v,a), and the range constructor when it turns out
+      // to be the same thing.
+      void
+      _M_fill_initialize(size_type __n, const value_type& __x)
+      {
+	for (; __n; --__n)
+	  push_back(__x);
+      }
+
+#if __cplusplus >= 201103L
+      // Called by list(n).
+      void
+      _M_default_initialize(size_type __n)
+      {
+	for (; __n; --__n)
+	  emplace_back();
+      }
+
+      // Called by resize(sz).
+      void
+      _M_default_append(size_type __n);
+#endif
+
+      // Internal assign functions follow.
+
+      // Called by the range assign to implement [23.1.1]/9
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 438. Ambiguity in the "do the right thing" clause
+      template<typename _Integer>
+	void
+	_M_assign_dispatch(_Integer __n, _Integer __val, __true_type)
+	{ _M_fill_assign(__n, __val); }
+
+      // Called by the range assign to implement [23.1.1]/9
+      template<typename _InputIterator>
+	void
+	_M_assign_dispatch(_InputIterator __first, _InputIterator __last,
+			   __false_type);
+
+      // Called by assign(n,t), and the range assign when it turns out
+      // to be the same thing.
+      void
+      _M_fill_assign(size_type __n, const value_type& __val);
+
+
+      // Moves the elements from [first,last) before position.
+      void
+      _M_transfer(iterator __position, iterator __first, iterator __last)
+      { __position._M_node->_M_transfer(__first._M_node, __last._M_node); }
+
+      // Inserts new element at position given and with value given.
+#if __cplusplus < 201103L
+      void
+      _M_insert(iterator __position, const value_type& __x)
+      {
+	_Node* __tmp = _M_create_node(__x);
+	__tmp->_M_hook(__position._M_node);
+	this->_M_inc_size(1);
+      }
+#else
+     template<typename... _Args>
+       void
+       _M_insert(iterator __position, _Args&&... __args)
+       {
+	 _Node* __tmp = _M_create_node(std::forward<_Args>(__args)...);
+	 __tmp->_M_hook(__position._M_node);
+	 this->_M_inc_size(1);
+       }
+#endif
+
+      // Erases element at position given.
+      void
+      _M_erase(iterator __position) _GLIBCXX_NOEXCEPT
+      {
+	this->_M_dec_size(1);
+	__position._M_node->_M_unhook();
+	_Node* __n = static_cast<_Node*>(__position._M_node);
+#if __cplusplus >= 201103L
+	_Node_alloc_traits::destroy(_M_get_Node_allocator(), __n->_M_valptr());
+#else
+	_Tp_alloc_type(_M_get_Node_allocator()).destroy(__n->_M_valptr());
+#endif
+
+	_M_put_node(__n);
+      }
+
+      // To implement the splice (and merge) bits of N1599.
+      void
+      _M_check_equal_allocators(list& __x) _GLIBCXX_NOEXCEPT
+      {
+	if (std::__alloc_neq<typename _Base::_Node_alloc_type>::
+	    _S_do_it(_M_get_Node_allocator(), __x._M_get_Node_allocator()))
+	  __builtin_abort();
+      }
+
+      // Used to implement resize.
+      const_iterator
+      _M_resize_pos(size_type& __new_size) const;
+
+#if __cplusplus >= 201103L
+      void
+      _M_move_assign(list&& __x, true_type) noexcept
+      {
+	this->clear();
+	this->_M_move_nodes(std::move(__x));
+	std::__alloc_on_move(this->_M_get_Node_allocator(),
+			     __x._M_get_Node_allocator());
+      }
+
+      void
+      _M_move_assign(list&& __x, false_type)
+      {
+	if (__x._M_get_Node_allocator() == this->_M_get_Node_allocator())
+	  _M_move_assign(std::move(__x), true_type{});
+	else
+	  // The rvalue's allocator cannot be moved, or is not equal,
+	  // so we need to individually move each element.
+	  _M_assign_dispatch(std::make_move_iterator(__x.begin()),
+			     std::make_move_iterator(__x.end()),
+			     __false_type{});
+      }
+#endif
+
+#if _GLIBCXX_USE_CXX11_ABI
+      // Update _M_size members after merging (some of) __src into __dest.
+      struct _Finalize_merge
+      {
+	explicit
+	_Finalize_merge(list& __dest, list& __src, const iterator& __src_next)
+	: _M_dest(__dest), _M_src(__src), _M_next(__src_next)
+	{ }
+
+	~_Finalize_merge()
+	{
+	  // For the common case, _M_next == _M_sec.end() and the std::distance
+	  // call is fast. But if any *iter1 < *iter2 comparison throws then we
+	  // have to count how many elements remain in _M_src.
+	  const size_t __num_unmerged = std::distance(_M_next, _M_src.end());
+	  const size_t __orig_size = _M_src._M_get_size();
+	  _M_dest._M_inc_size(__orig_size - __num_unmerged);
+	  _M_src._M_set_size(__num_unmerged);
+	}
+
+	list& _M_dest;
+	list& _M_src;
+	const iterator& _M_next;
+
+#if __cplusplus >= 201103L
+	_Finalize_merge(const _Finalize_merge&) = delete;
+#endif
+      };
+#else
+      struct _Finalize_merge
+      { explicit _Finalize_merge(list&, list&, const iterator&) { } };
+#endif
+
+    };
+
+#if __cpp_deduction_guides >= 201606
+  template<typename _InputIterator, typename _ValT
+	     = typename iterator_traits<_InputIterator>::value_type,
+	   typename _Allocator = allocator<_ValT>,
+	   typename = _RequireInputIter<_InputIterator>,
+	   typename = _RequireAllocator<_Allocator>>
+    list(_InputIterator, _InputIterator, _Allocator = _Allocator())
+      -> list<_ValT, _Allocator>;
+#endif
+
+_GLIBCXX_END_NAMESPACE_CXX11
+
+  /**
+   *  @brief  List equality comparison.
+   *  @param  __x  A %list.
+   *  @param  __y  A %list of the same type as @a __x.
+   *  @return  True iff the size and elements of the lists are equal.
+   *
+   *  This is an equivalence relation.  It is linear in the size of
+   *  the lists.  Lists are considered equivalent if their sizes are
+   *  equal, and if corresponding elements compare equal.
+  */
+  template<typename _Tp, typename _Alloc>
+    _GLIBCXX_NODISCARD
+    inline bool
+    operator==(const list<_Tp, _Alloc>& __x, const list<_Tp, _Alloc>& __y)
+    {
+#if _GLIBCXX_USE_CXX11_ABI
+      if (__x.size() != __y.size())
+	return false;
+#endif
+
+      typedef typename list<_Tp, _Alloc>::const_iterator const_iterator;
+      const_iterator __end1 = __x.end();
+      const_iterator __end2 = __y.end();
+
+      const_iterator __i1 = __x.begin();
+      const_iterator __i2 = __y.begin();
+      while (__i1 != __end1 && __i2 != __end2 && *__i1 == *__i2)
+	{
+	  ++__i1;
+	  ++__i2;
+	}
+      return __i1 == __end1 && __i2 == __end2;
+    }
+
+#if __cpp_lib_three_way_comparison
+/**
+   *  @brief  List ordering relation.
+   *  @param  __x  A `list`.
+   *  @param  __y  A `list` of the same type as `__x`.
+   *  @return  A value indicating whether `__x` is less than, equal to,
+   *           greater than, or incomparable with `__y`.
+   *
+   *  See `std::lexicographical_compare_three_way()` for how the determination
+   *  is made. This operator is used to synthesize relational operators like
+   *  `<` and `>=` etc.
+  */
+  template<typename _Tp, typename _Alloc>
+    [[nodiscard]]
+    inline __detail::__synth3way_t<_Tp>
+    operator<=>(const list<_Tp, _Alloc>& __x, const list<_Tp, _Alloc>& __y)
+    {
+      return std::lexicographical_compare_three_way(__x.begin(), __x.end(),
+						    __y.begin(), __y.end(),
+						    __detail::__synth3way);
+    }
+#else
+  /**
+   *  @brief  List ordering relation.
+   *  @param  __x  A %list.
+   *  @param  __y  A %list of the same type as @a __x.
+   *  @return  True iff @a __x is lexicographically less than @a __y.
+   *
+   *  This is a total ordering relation.  It is linear in the size of the
+   *  lists.  The elements must be comparable with @c <.
+   *
+   *  See std::lexicographical_compare() for how the determination is made.
+  */
+  template<typename _Tp, typename _Alloc>
+    _GLIBCXX_NODISCARD
+    inline bool
+    operator<(const list<_Tp, _Alloc>& __x, const list<_Tp, _Alloc>& __y)
+    { return std::lexicographical_compare(__x.begin(), __x.end(),
+					  __y.begin(), __y.end()); }
+
+  /// Based on operator==
+  template<typename _Tp, typename _Alloc>
+    _GLIBCXX_NODISCARD
+    inline bool
+    operator!=(const list<_Tp, _Alloc>& __x, const list<_Tp, _Alloc>& __y)
+    { return !(__x == __y); }
+
+  /// Based on operator<
+  template<typename _Tp, typename _Alloc>
+    _GLIBCXX_NODISCARD
+    inline bool
+    operator>(const list<_Tp, _Alloc>& __x, const list<_Tp, _Alloc>& __y)
+    { return __y < __x; }
+
+  /// Based on operator<
+  template<typename _Tp, typename _Alloc>
+    _GLIBCXX_NODISCARD
+    inline bool
+    operator<=(const list<_Tp, _Alloc>& __x, const list<_Tp, _Alloc>& __y)
+    { return !(__y < __x); }
+
+  /// Based on operator<
+  template<typename _Tp, typename _Alloc>
+    _GLIBCXX_NODISCARD
+    inline bool
+    operator>=(const list<_Tp, _Alloc>& __x, const list<_Tp, _Alloc>& __y)
+    { return !(__x < __y); }
+#endif // three-way comparison
+
+  /// See std::list::swap().
+  template<typename _Tp, typename _Alloc>
+    inline void
+    swap(list<_Tp, _Alloc>& __x, list<_Tp, _Alloc>& __y)
+    _GLIBCXX_NOEXCEPT_IF(noexcept(__x.swap(__y)))
+    { __x.swap(__y); }
+
+_GLIBCXX_END_NAMESPACE_CONTAINER
+
+#if _GLIBCXX_USE_CXX11_ABI
+
+  // Detect when distance is used to compute the size of the whole list.
+  template<typename _Tp>
+    inline ptrdiff_t
+    __distance(_GLIBCXX_STD_C::_List_iterator<_Tp> __first,
+	       _GLIBCXX_STD_C::_List_iterator<_Tp> __last,
+	       input_iterator_tag __tag)
+    {
+      typedef _GLIBCXX_STD_C::_List_const_iterator<_Tp> _CIter;
+      return std::__distance(_CIter(__first), _CIter(__last), __tag);
+    }
+
+  template<typename _Tp>
+    inline ptrdiff_t
+    __distance(_GLIBCXX_STD_C::_List_const_iterator<_Tp> __first,
+	       _GLIBCXX_STD_C::_List_const_iterator<_Tp> __last,
+	       input_iterator_tag)
+    {
+      typedef __detail::_List_node_header _Sentinel;
+      _GLIBCXX_STD_C::_List_const_iterator<_Tp> __beyond = __last;
+      ++__beyond;
+      const bool __whole = __first == __beyond;
+      if (__builtin_constant_p (__whole) && __whole)
+	return static_cast<const _Sentinel*>(__last._M_node)->_M_size;
+
+      ptrdiff_t __n = 0;
+      while (__first != __last)
+	{
+	  ++__first;
+	  ++__n;
+	}
+      return __n;
+    }
+#endif
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif /* _STL_LIST_H */
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stl_map.h
@@ -0,0 +1,1616 @@
+// Map implementation -*- C++ -*-
+
+// Copyright (C) 2001-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/*
+ *
+ * Copyright (c) 1994
+ * Hewlett-Packard Company
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Hewlett-Packard Company makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ *
+ *
+ * Copyright (c) 1996,1997
+ * Silicon Graphics Computer Systems, Inc.
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Silicon Graphics makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ */
+
+/** @file bits/stl_map.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{map}
+ */
+
+#ifndef _STL_MAP_H
+#define _STL_MAP_H 1
+
+#include <bits/functexcept.h>
+#include <bits/concept_check.h>
+#if __cplusplus >= 201103L
+#include <initializer_list>
+#include <tuple>
+#endif
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+_GLIBCXX_BEGIN_NAMESPACE_CONTAINER
+
+  template <typename _Key, typename _Tp, typename _Compare, typename _Alloc>
+    class multimap;
+
+  /**
+   *  @brief A standard container made up of (key,value) pairs, which can be
+   *  retrieved based on a key, in logarithmic time.
+   *
+   *  @ingroup associative_containers
+   *
+   *  @tparam _Key  Type of key objects.
+   *  @tparam  _Tp  Type of mapped objects.
+   *  @tparam _Compare  Comparison function object type, defaults to less<_Key>.
+   *  @tparam _Alloc  Allocator type, defaults to
+   *                  allocator<pair<const _Key, _Tp>.
+   *
+   *  Meets the requirements of a <a href="tables.html#65">container</a>, a
+   *  <a href="tables.html#66">reversible container</a>, and an
+   *  <a href="tables.html#69">associative container</a> (using unique keys).
+   *  For a @c map<Key,T> the key_type is Key, the mapped_type is T, and the
+   *  value_type is std::pair<const Key,T>.
+   *
+   *  Maps support bidirectional iterators.
+   *
+   *  The private tree data is declared exactly the same way for map and
+   *  multimap; the distinction is made entirely in how the tree functions are
+   *  called (*_unique versus *_equal, same as the standard).
+  */
+  template <typename _Key, typename _Tp, typename _Compare = std::less<_Key>,
+	    typename _Alloc = std::allocator<std::pair<const _Key, _Tp> > >
+    class map
+    {
+    public:
+      typedef _Key					key_type;
+      typedef _Tp					mapped_type;
+      typedef std::pair<const _Key, _Tp>		value_type;
+      typedef _Compare					key_compare;
+      typedef _Alloc					allocator_type;
+
+    private:
+#ifdef _GLIBCXX_CONCEPT_CHECKS
+      // concept requirements
+      typedef typename _Alloc::value_type		_Alloc_value_type;
+# if __cplusplus < 201103L
+      __glibcxx_class_requires(_Tp, _SGIAssignableConcept)
+# endif
+      __glibcxx_class_requires4(_Compare, bool, _Key, _Key,
+				_BinaryFunctionConcept)
+      __glibcxx_class_requires2(value_type, _Alloc_value_type, _SameTypeConcept)
+#endif
+
+#if __cplusplus >= 201103L
+#if __cplusplus > 201703L || defined __STRICT_ANSI__
+      static_assert(is_same<typename _Alloc::value_type, value_type>::value,
+	  "std::map must have the same value_type as its allocator");
+#endif
+#endif
+
+    public:
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+      class value_compare
+      : public std::binary_function<value_type, value_type, bool>
+      {
+	friend class map<_Key, _Tp, _Compare, _Alloc>;
+      protected:
+	_Compare comp;
+
+	value_compare(_Compare __c)
+	: comp(__c) { }
+
+      public:
+	bool operator()(const value_type& __x, const value_type& __y) const
+	{ return comp(__x.first, __y.first); }
+      };
+#pragma GCC diagnostic pop
+
+    private:
+      /// This turns a red-black tree into a [multi]map.
+      typedef typename __gnu_cxx::__alloc_traits<_Alloc>::template
+	rebind<value_type>::other _Pair_alloc_type;
+
+      typedef _Rb_tree<key_type, value_type, _Select1st<value_type>,
+		       key_compare, _Pair_alloc_type> _Rep_type;
+
+      /// The actual tree structure.
+      _Rep_type _M_t;
+
+      typedef __gnu_cxx::__alloc_traits<_Pair_alloc_type> _Alloc_traits;
+
+#if __cplusplus >= 201703L
+      template<typename _Up, typename _Vp = remove_reference_t<_Up>>
+	static constexpr bool __usable_key
+	  = __or_v<is_same<const _Vp, const _Key>,
+		   __and_<is_scalar<_Vp>, is_scalar<_Key>>>;
+#endif
+
+    public:
+      // many of these are specified differently in ISO, but the following are
+      // "functionally equivalent"
+      typedef typename _Alloc_traits::pointer		 pointer;
+      typedef typename _Alloc_traits::const_pointer	 const_pointer;
+      typedef typename _Alloc_traits::reference		 reference;
+      typedef typename _Alloc_traits::const_reference	 const_reference;
+      typedef typename _Rep_type::iterator		 iterator;
+      typedef typename _Rep_type::const_iterator	 const_iterator;
+      typedef typename _Rep_type::size_type		 size_type;
+      typedef typename _Rep_type::difference_type	 difference_type;
+      typedef typename _Rep_type::reverse_iterator	 reverse_iterator;
+      typedef typename _Rep_type::const_reverse_iterator const_reverse_iterator;
+
+#if __cplusplus > 201402L
+      using node_type = typename _Rep_type::node_type;
+      using insert_return_type = typename _Rep_type::insert_return_type;
+#endif
+
+      // [23.3.1.1] construct/copy/destroy
+      // (get_allocator() is also listed in this section)
+
+      /**
+       *  @brief  Default constructor creates no elements.
+       */
+#if __cplusplus < 201103L
+      map() : _M_t() { }
+#else
+      map() = default;
+#endif
+
+      /**
+       *  @brief  Creates a %map with no elements.
+       *  @param  __comp  A comparison object.
+       *  @param  __a  An allocator object.
+       */
+      explicit
+      map(const _Compare& __comp,
+	  const allocator_type& __a = allocator_type())
+      : _M_t(__comp, _Pair_alloc_type(__a)) { }
+
+      /**
+       *  @brief  %Map copy constructor.
+       *
+       *  Whether the allocator is copied depends on the allocator traits.
+       */
+#if __cplusplus < 201103L
+      map(const map& __x)
+      : _M_t(__x._M_t) { }
+#else
+      map(const map&) = default;
+
+      /**
+       *  @brief  %Map move constructor.
+       *
+       *  The newly-created %map contains the exact contents of the moved
+       *  instance. The moved instance is a valid, but unspecified, %map.
+       */
+      map(map&&) = default;
+
+      /**
+       *  @brief  Builds a %map from an initializer_list.
+       *  @param  __l  An initializer_list.
+       *  @param  __comp  A comparison object.
+       *  @param  __a  An allocator object.
+       *
+       *  Create a %map consisting of copies of the elements in the
+       *  initializer_list @a __l.
+       *  This is linear in N if the range is already sorted, and NlogN
+       *  otherwise (where N is @a __l.size()).
+       */
+      map(initializer_list<value_type> __l,
+	  const _Compare& __comp = _Compare(),
+	  const allocator_type& __a = allocator_type())
+      : _M_t(__comp, _Pair_alloc_type(__a))
+      { _M_t._M_insert_range_unique(__l.begin(), __l.end()); }
+
+      /// Allocator-extended default constructor.
+      explicit
+      map(const allocator_type& __a)
+      : _M_t(_Pair_alloc_type(__a)) { }
+
+      /// Allocator-extended copy constructor.
+      map(const map& __m, const __type_identity_t<allocator_type>& __a)
+      : _M_t(__m._M_t, _Pair_alloc_type(__a)) { }
+
+      /// Allocator-extended move constructor.
+      map(map&& __m, const __type_identity_t<allocator_type>& __a)
+      noexcept(is_nothrow_copy_constructible<_Compare>::value
+	       && _Alloc_traits::_S_always_equal())
+      : _M_t(std::move(__m._M_t), _Pair_alloc_type(__a)) { }
+
+      /// Allocator-extended initialier-list constructor.
+      map(initializer_list<value_type> __l, const allocator_type& __a)
+      : _M_t(_Pair_alloc_type(__a))
+      { _M_t._M_insert_range_unique(__l.begin(), __l.end()); }
+
+      /// Allocator-extended range constructor.
+      template<typename _InputIterator>
+	map(_InputIterator __first, _InputIterator __last,
+	    const allocator_type& __a)
+	: _M_t(_Pair_alloc_type(__a))
+	{ _M_t._M_insert_range_unique(__first, __last); }
+#endif
+
+      /**
+       *  @brief  Builds a %map from a range.
+       *  @param  __first  An input iterator.
+       *  @param  __last  An input iterator.
+       *
+       *  Create a %map consisting of copies of the elements from
+       *  [__first,__last).  This is linear in N if the range is
+       *  already sorted, and NlogN otherwise (where N is
+       *  distance(__first,__last)).
+       */
+      template<typename _InputIterator>
+	map(_InputIterator __first, _InputIterator __last)
+	: _M_t()
+	{ _M_t._M_insert_range_unique(__first, __last); }
+
+      /**
+       *  @brief  Builds a %map from a range.
+       *  @param  __first  An input iterator.
+       *  @param  __last  An input iterator.
+       *  @param  __comp  A comparison functor.
+       *  @param  __a  An allocator object.
+       *
+       *  Create a %map consisting of copies of the elements from
+       *  [__first,__last).  This is linear in N if the range is
+       *  already sorted, and NlogN otherwise (where N is
+       *  distance(__first,__last)).
+       */
+      template<typename _InputIterator>
+	map(_InputIterator __first, _InputIterator __last,
+	    const _Compare& __comp,
+	    const allocator_type& __a = allocator_type())
+	: _M_t(__comp, _Pair_alloc_type(__a))
+	{ _M_t._M_insert_range_unique(__first, __last); }
+
+#if __cplusplus >= 201103L
+      /**
+       *  The dtor only erases the elements, and note that if the elements
+       *  themselves are pointers, the pointed-to memory is not touched in any
+       *  way.  Managing the pointer is the user's responsibility.
+       */
+      ~map() = default;
+#endif
+
+      /**
+       *  @brief  %Map assignment operator.
+       *
+       *  Whether the allocator is copied depends on the allocator traits.
+       */
+#if __cplusplus < 201103L
+      map&
+      operator=(const map& __x)
+      {
+	_M_t = __x._M_t;
+	return *this;
+      }
+#else
+      map&
+      operator=(const map&) = default;
+
+      /// Move assignment operator.
+      map&
+      operator=(map&&) = default;
+
+      /**
+       *  @brief  %Map list assignment operator.
+       *  @param  __l  An initializer_list.
+       *
+       *  This function fills a %map with copies of the elements in the
+       *  initializer list @a __l.
+       *
+       *  Note that the assignment completely changes the %map and
+       *  that the resulting %map's size is the same as the number
+       *  of elements assigned.
+       */
+      map&
+      operator=(initializer_list<value_type> __l)
+      {
+	_M_t._M_assign_unique(__l.begin(), __l.end());
+	return *this;
+      }
+#endif
+
+      /// Get a copy of the memory allocation object.
+      allocator_type
+      get_allocator() const _GLIBCXX_NOEXCEPT
+      { return allocator_type(_M_t.get_allocator()); }
+
+      // iterators
+      /**
+       *  Returns a read/write iterator that points to the first pair in the
+       *  %map.
+       *  Iteration is done in ascending order according to the keys.
+       */
+      iterator
+      begin() _GLIBCXX_NOEXCEPT
+      { return _M_t.begin(); }
+
+      /**
+       *  Returns a read-only (constant) iterator that points to the first pair
+       *  in the %map.  Iteration is done in ascending order according to the
+       *  keys.
+       */
+      const_iterator
+      begin() const _GLIBCXX_NOEXCEPT
+      { return _M_t.begin(); }
+
+      /**
+       *  Returns a read/write iterator that points one past the last
+       *  pair in the %map.  Iteration is done in ascending order
+       *  according to the keys.
+       */
+      iterator
+      end() _GLIBCXX_NOEXCEPT
+      { return _M_t.end(); }
+
+      /**
+       *  Returns a read-only (constant) iterator that points one past the last
+       *  pair in the %map.  Iteration is done in ascending order according to
+       *  the keys.
+       */
+      const_iterator
+      end() const _GLIBCXX_NOEXCEPT
+      { return _M_t.end(); }
+
+      /**
+       *  Returns a read/write reverse iterator that points to the last pair in
+       *  the %map.  Iteration is done in descending order according to the
+       *  keys.
+       */
+      reverse_iterator
+      rbegin() _GLIBCXX_NOEXCEPT
+      { return _M_t.rbegin(); }
+
+      /**
+       *  Returns a read-only (constant) reverse iterator that points to the
+       *  last pair in the %map.  Iteration is done in descending order
+       *  according to the keys.
+       */
+      const_reverse_iterator
+      rbegin() const _GLIBCXX_NOEXCEPT
+      { return _M_t.rbegin(); }
+
+      /**
+       *  Returns a read/write reverse iterator that points to one before the
+       *  first pair in the %map.  Iteration is done in descending order
+       *  according to the keys.
+       */
+      reverse_iterator
+      rend() _GLIBCXX_NOEXCEPT
+      { return _M_t.rend(); }
+
+      /**
+       *  Returns a read-only (constant) reverse iterator that points to one
+       *  before the first pair in the %map.  Iteration is done in descending
+       *  order according to the keys.
+       */
+      const_reverse_iterator
+      rend() const _GLIBCXX_NOEXCEPT
+      { return _M_t.rend(); }
+
+#if __cplusplus >= 201103L
+      /**
+       *  Returns a read-only (constant) iterator that points to the first pair
+       *  in the %map.  Iteration is done in ascending order according to the
+       *  keys.
+       */
+      const_iterator
+      cbegin() const noexcept
+      { return _M_t.begin(); }
+
+      /**
+       *  Returns a read-only (constant) iterator that points one past the last
+       *  pair in the %map.  Iteration is done in ascending order according to
+       *  the keys.
+       */
+      const_iterator
+      cend() const noexcept
+      { return _M_t.end(); }
+
+      /**
+       *  Returns a read-only (constant) reverse iterator that points to the
+       *  last pair in the %map.  Iteration is done in descending order
+       *  according to the keys.
+       */
+      const_reverse_iterator
+      crbegin() const noexcept
+      { return _M_t.rbegin(); }
+
+      /**
+       *  Returns a read-only (constant) reverse iterator that points to one
+       *  before the first pair in the %map.  Iteration is done in descending
+       *  order according to the keys.
+       */
+      const_reverse_iterator
+      crend() const noexcept
+      { return _M_t.rend(); }
+#endif
+
+      // capacity
+      /** Returns true if the %map is empty.  (Thus begin() would equal
+       *  end().)
+      */
+      _GLIBCXX_NODISCARD bool
+      empty() const _GLIBCXX_NOEXCEPT
+      { return _M_t.empty(); }
+
+      /** Returns the size of the %map.  */
+      size_type
+      size() const _GLIBCXX_NOEXCEPT
+      { return _M_t.size(); }
+
+      /** Returns the maximum size of the %map.  */
+      size_type
+      max_size() const _GLIBCXX_NOEXCEPT
+      { return _M_t.max_size(); }
+
+      // [23.3.1.2] element access
+      /**
+       *  @brief  Subscript ( @c [] ) access to %map data.
+       *  @param  __k  The key for which data should be retrieved.
+       *  @return  A reference to the data of the (key,data) %pair.
+       *
+       *  Allows for easy lookup with the subscript ( @c [] )
+       *  operator.  Returns data associated with the key specified in
+       *  subscript.  If the key does not exist, a pair with that key
+       *  is created using default values, which is then returned.
+       *
+       *  Lookup requires logarithmic time.
+       */
+      mapped_type&
+      operator[](const key_type& __k)
+      {
+	// concept requirements
+	__glibcxx_function_requires(_DefaultConstructibleConcept<mapped_type>)
+
+	iterator __i = lower_bound(__k);
+	// __i->first is greater than or equivalent to __k.
+	if (__i == end() || key_comp()(__k, (*__i).first))
+#if __cplusplus >= 201103L
+	  __i = _M_t._M_emplace_hint_unique(__i, std::piecewise_construct,
+					    std::tuple<const key_type&>(__k),
+					    std::tuple<>());
+#else
+	  __i = insert(__i, value_type(__k, mapped_type()));
+#endif
+	return (*__i).second;
+      }
+
+#if __cplusplus >= 201103L
+      mapped_type&
+      operator[](key_type&& __k)
+      {
+	// concept requirements
+	__glibcxx_function_requires(_DefaultConstructibleConcept<mapped_type>)
+
+	iterator __i = lower_bound(__k);
+	// __i->first is greater than or equivalent to __k.
+	if (__i == end() || key_comp()(__k, (*__i).first))
+	  __i = _M_t._M_emplace_hint_unique(__i, std::piecewise_construct,
+					std::forward_as_tuple(std::move(__k)),
+					std::tuple<>());
+	return (*__i).second;
+      }
+#endif
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // DR 464. Suggestion for new member functions in standard containers.
+      /**
+       *  @brief  Access to %map data.
+       *  @param  __k  The key for which data should be retrieved.
+       *  @return  A reference to the data whose key is equivalent to @a __k, if
+       *           such a data is present in the %map.
+       *  @throw  std::out_of_range  If no such data is present.
+       */
+      mapped_type&
+      at(const key_type& __k)
+      {
+	iterator __i = lower_bound(__k);
+	if (__i == end() || key_comp()(__k, (*__i).first))
+	  __throw_out_of_range(__N("map::at"));
+	return (*__i).second;
+      }
+
+      const mapped_type&
+      at(const key_type& __k) const
+      {
+	const_iterator __i = lower_bound(__k);
+	if (__i == end() || key_comp()(__k, (*__i).first))
+	  __throw_out_of_range(__N("map::at"));
+	return (*__i).second;
+      }
+
+      // modifiers
+#if __cplusplus >= 201103L
+      /**
+       *  @brief Attempts to build and insert a std::pair into the %map.
+       *
+       *  @param __args  Arguments used to generate a new pair instance (see
+       *	        std::piecewise_contruct for passing arguments to each
+       *	        part of the pair constructor).
+       *
+       *  @return  A pair, of which the first element is an iterator that points
+       *           to the possibly inserted pair, and the second is a bool that
+       *           is true if the pair was actually inserted.
+       *
+       *  This function attempts to build and insert a (key, value) %pair into
+       *  the %map.
+       *  A %map relies on unique keys and thus a %pair is only inserted if its
+       *  first element (the key) is not already present in the %map.
+       *
+       *  Insertion requires logarithmic time.
+       */
+      template<typename... _Args>
+	std::pair<iterator, bool>
+	emplace(_Args&&... __args)
+	{
+#if __cplusplus >= 201703L
+	  if constexpr (sizeof...(_Args) == 2)
+	    if constexpr (is_same_v<allocator_type, allocator<value_type>>)
+	      {
+		auto&& [__a, __v] = pair<_Args&...>(__args...);
+		if constexpr (__usable_key<decltype(__a)>)
+		  {
+		    const key_type& __k = __a;
+		    iterator __i = lower_bound(__k);
+		    if (__i == end() || key_comp()(__k, (*__i).first))
+		      {
+			__i = emplace_hint(__i, std::forward<_Args>(__args)...);
+			return {__i, true};
+		      }
+		    return {__i, false};
+		  }
+	      }
+#endif
+	  return _M_t._M_emplace_unique(std::forward<_Args>(__args)...);
+	}
+
+      /**
+       *  @brief Attempts to build and insert a std::pair into the %map.
+       *
+       *  @param  __pos  An iterator that serves as a hint as to where the pair
+       *                should be inserted.
+       *  @param  __args  Arguments used to generate a new pair instance (see
+       *	         std::piecewise_contruct for passing arguments to each
+       *	         part of the pair constructor).
+       *  @return An iterator that points to the element with key of the
+       *          std::pair built from @a __args (may or may not be that
+       *          std::pair).
+       *
+       *  This function is not concerned about whether the insertion took place,
+       *  and thus does not return a boolean like the single-argument emplace()
+       *  does.
+       *  Note that the first parameter is only a hint and can potentially
+       *  improve the performance of the insertion process. A bad hint would
+       *  cause no gains in efficiency.
+       *
+       *  See
+       *  https://gcc.gnu.org/onlinedocs/libstdc++/manual/associative.html#containers.associative.insert_hints
+       *  for more on @a hinting.
+       *
+       *  Insertion requires logarithmic time (if the hint is not taken).
+       */
+      template<typename... _Args>
+	iterator
+	emplace_hint(const_iterator __pos, _Args&&... __args)
+	{
+	  return _M_t._M_emplace_hint_unique(__pos,
+					     std::forward<_Args>(__args)...);
+	}
+#endif
+
+#if __cplusplus > 201402L
+      /// Extract a node.
+      node_type
+      extract(const_iterator __pos)
+      {
+	__glibcxx_assert(__pos != end());
+	return _M_t.extract(__pos);
+      }
+
+      /// Extract a node.
+      node_type
+      extract(const key_type& __x)
+      { return _M_t.extract(__x); }
+
+      /// Re-insert an extracted node.
+      insert_return_type
+      insert(node_type&& __nh)
+      { return _M_t._M_reinsert_node_unique(std::move(__nh)); }
+
+      /// Re-insert an extracted node.
+      iterator
+      insert(const_iterator __hint, node_type&& __nh)
+      { return _M_t._M_reinsert_node_hint_unique(__hint, std::move(__nh)); }
+
+      template<typename, typename>
+	friend struct std::_Rb_tree_merge_helper;
+
+      template<typename _Cmp2>
+	void
+	merge(map<_Key, _Tp, _Cmp2, _Alloc>& __source)
+	{
+	  using _Merge_helper = _Rb_tree_merge_helper<map, _Cmp2>;
+	  _M_t._M_merge_unique(_Merge_helper::_S_get_tree(__source));
+	}
+
+      template<typename _Cmp2>
+	void
+	merge(map<_Key, _Tp, _Cmp2, _Alloc>&& __source)
+	{ merge(__source); }
+
+      template<typename _Cmp2>
+	void
+	merge(multimap<_Key, _Tp, _Cmp2, _Alloc>& __source)
+	{
+	  using _Merge_helper = _Rb_tree_merge_helper<map, _Cmp2>;
+	  _M_t._M_merge_unique(_Merge_helper::_S_get_tree(__source));
+	}
+
+      template<typename _Cmp2>
+	void
+	merge(multimap<_Key, _Tp, _Cmp2, _Alloc>&& __source)
+	{ merge(__source); }
+#endif // C++17
+
+#if __cplusplus > 201402L
+#define __cpp_lib_map_try_emplace 201411L
+      /**
+       *  @brief Attempts to build and insert a std::pair into the %map.
+       *
+       *  @param __k    Key to use for finding a possibly existing pair in
+       *                the map.
+       *  @param __args  Arguments used to generate the .second for a new pair
+       *                instance.
+       *
+       *  @return  A pair, of which the first element is an iterator that points
+       *           to the possibly inserted pair, and the second is a bool that
+       *           is true if the pair was actually inserted.
+       *
+       *  This function attempts to build and insert a (key, value) %pair into
+       *  the %map.
+       *  A %map relies on unique keys and thus a %pair is only inserted if its
+       *  first element (the key) is not already present in the %map.
+       *  If a %pair is not inserted, this function has no effect.
+       *
+       *  Insertion requires logarithmic time.
+       */
+      template <typename... _Args>
+	pair<iterator, bool>
+	try_emplace(const key_type& __k, _Args&&... __args)
+	{
+	  iterator __i = lower_bound(__k);
+	  if (__i == end() || key_comp()(__k, (*__i).first))
+	    {
+	      __i = emplace_hint(__i, std::piecewise_construct,
+				 std::forward_as_tuple(__k),
+				 std::forward_as_tuple(
+				   std::forward<_Args>(__args)...));
+	      return {__i, true};
+	    }
+	  return {__i, false};
+	}
+
+      // move-capable overload
+      template <typename... _Args>
+	pair<iterator, bool>
+	try_emplace(key_type&& __k, _Args&&... __args)
+	{
+	  iterator __i = lower_bound(__k);
+	  if (__i == end() || key_comp()(__k, (*__i).first))
+	    {
+	      __i = emplace_hint(__i, std::piecewise_construct,
+				 std::forward_as_tuple(std::move(__k)),
+				 std::forward_as_tuple(
+				   std::forward<_Args>(__args)...));
+	      return {__i, true};
+	    }
+	  return {__i, false};
+	}
+
+      /**
+       *  @brief Attempts to build and insert a std::pair into the %map.
+       *
+       *  @param  __hint  An iterator that serves as a hint as to where the
+       *                  pair should be inserted.
+       *  @param __k    Key to use for finding a possibly existing pair in
+       *                the map.
+       *  @param __args  Arguments used to generate the .second for a new pair
+       *                instance.
+       *  @return An iterator that points to the element with key of the
+       *          std::pair built from @a __args (may or may not be that
+       *          std::pair).
+       *
+       *  This function is not concerned about whether the insertion took place,
+       *  and thus does not return a boolean like the single-argument
+       *  try_emplace() does. However, if insertion did not take place,
+       *  this function has no effect.
+       *  Note that the first parameter is only a hint and can potentially
+       *  improve the performance of the insertion process. A bad hint would
+       *  cause no gains in efficiency.
+       *
+       *  See
+       *  https://gcc.gnu.org/onlinedocs/libstdc++/manual/associative.html#containers.associative.insert_hints
+       *  for more on @a hinting.
+       *
+       *  Insertion requires logarithmic time (if the hint is not taken).
+       */
+      template <typename... _Args>
+	iterator
+	try_emplace(const_iterator __hint, const key_type& __k,
+		    _Args&&... __args)
+	{
+	  iterator __i;
+	  auto __true_hint = _M_t._M_get_insert_hint_unique_pos(__hint, __k);
+	  if (__true_hint.second)
+	    __i = emplace_hint(iterator(__true_hint.second),
+			       std::piecewise_construct,
+			       std::forward_as_tuple(__k),
+			       std::forward_as_tuple(
+				 std::forward<_Args>(__args)...));
+	  else
+	    __i = iterator(__true_hint.first);
+	  return __i;
+	}
+
+      // move-capable overload
+      template <typename... _Args>
+	iterator
+	try_emplace(const_iterator __hint, key_type&& __k, _Args&&... __args)
+	{
+	  iterator __i;
+	  auto __true_hint = _M_t._M_get_insert_hint_unique_pos(__hint, __k);
+	  if (__true_hint.second)
+	    __i = emplace_hint(iterator(__true_hint.second),
+			       std::piecewise_construct,
+			       std::forward_as_tuple(std::move(__k)),
+			       std::forward_as_tuple(
+				 std::forward<_Args>(__args)...));
+	  else
+	    __i = iterator(__true_hint.first);
+	  return __i;
+	}
+#endif
+
+      /**
+       *  @brief Attempts to insert a std::pair into the %map.
+       *  @param __x Pair to be inserted (see std::make_pair for easy
+       *	     creation of pairs).
+       *
+       *  @return  A pair, of which the first element is an iterator that
+       *           points to the possibly inserted pair, and the second is
+       *           a bool that is true if the pair was actually inserted.
+       *
+       *  This function attempts to insert a (key, value) %pair into the %map.
+       *  A %map relies on unique keys and thus a %pair is only inserted if its
+       *  first element (the key) is not already present in the %map.
+       *
+       *  Insertion requires logarithmic time.
+       *  @{
+       */
+      std::pair<iterator, bool>
+      insert(const value_type& __x)
+      { return _M_t._M_insert_unique(__x); }
+
+#if __cplusplus >= 201103L
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 2354. Unnecessary copying when inserting into maps with braced-init
+      std::pair<iterator, bool>
+      insert(value_type&& __x)
+      { return _M_t._M_insert_unique(std::move(__x)); }
+
+      template<typename _Pair>
+	__enable_if_t<is_constructible<value_type, _Pair>::value,
+		      pair<iterator, bool>>
+	insert(_Pair&& __x)
+	{
+#if __cplusplus >= 201703L
+	  using _P2 = remove_reference_t<_Pair>;
+	  if constexpr (__is_pair<_P2>)
+	    if constexpr (is_same_v<allocator_type, allocator<value_type>>)
+	      if constexpr (__usable_key<typename _P2::first_type>)
+		{
+		  const key_type& __k = __x.first;
+		  iterator __i = lower_bound(__k);
+		  if (__i == end() || key_comp()(__k, (*__i).first))
+		    {
+		      __i = emplace_hint(__i, std::forward<_Pair>(__x));
+		      return {__i, true};
+		    }
+		  return {__i, false};
+		}
+#endif
+	  return _M_t._M_emplace_unique(std::forward<_Pair>(__x));
+	}
+#endif
+      /// @}
+
+#if __cplusplus >= 201103L
+      /**
+       *  @brief Attempts to insert a list of std::pairs into the %map.
+       *  @param  __list  A std::initializer_list<value_type> of pairs to be
+       *                  inserted.
+       *
+       *  Complexity similar to that of the range constructor.
+       */
+      void
+      insert(std::initializer_list<value_type> __list)
+      { insert(__list.begin(), __list.end()); }
+#endif
+
+      /**
+       *  @brief Attempts to insert a std::pair into the %map.
+       *  @param  __position  An iterator that serves as a hint as to where the
+       *                    pair should be inserted.
+       *  @param  __x  Pair to be inserted (see std::make_pair for easy creation
+       *               of pairs).
+       *  @return An iterator that points to the element with key of
+       *           @a __x (may or may not be the %pair passed in).
+       *
+
+       *  This function is not concerned about whether the insertion
+       *  took place, and thus does not return a boolean like the
+       *  single-argument insert() does.  Note that the first
+       *  parameter is only a hint and can potentially improve the
+       *  performance of the insertion process.  A bad hint would
+       *  cause no gains in efficiency.
+       *
+       *  See
+       *  https://gcc.gnu.org/onlinedocs/libstdc++/manual/associative.html#containers.associative.insert_hints
+       *  for more on @a hinting.
+       *
+       *  Insertion requires logarithmic time (if the hint is not taken).
+       *  @{
+       */
+      iterator
+#if __cplusplus >= 201103L
+      insert(const_iterator __position, const value_type& __x)
+#else
+      insert(iterator __position, const value_type& __x)
+#endif
+      { return _M_t._M_insert_unique_(__position, __x); }
+
+#if __cplusplus >= 201103L
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 2354. Unnecessary copying when inserting into maps with braced-init
+      iterator
+      insert(const_iterator __position, value_type&& __x)
+      { return _M_t._M_insert_unique_(__position, std::move(__x)); }
+
+      template<typename _Pair>
+	__enable_if_t<is_constructible<value_type, _Pair>::value, iterator>
+	insert(const_iterator __position, _Pair&& __x)
+	{
+	  return _M_t._M_emplace_hint_unique(__position,
+					     std::forward<_Pair>(__x));
+	}
+#endif
+      /// @}
+
+      /**
+       *  @brief Template function that attempts to insert a range of elements.
+       *  @param  __first  Iterator pointing to the start of the range to be
+       *                   inserted.
+       *  @param  __last  Iterator pointing to the end of the range.
+       *
+       *  Complexity similar to that of the range constructor.
+       */
+      template<typename _InputIterator>
+	void
+	insert(_InputIterator __first, _InputIterator __last)
+	{ _M_t._M_insert_range_unique(__first, __last); }
+
+#if __cplusplus > 201402L
+      /**
+       *  @brief Attempts to insert or assign a std::pair into the %map.
+       *  @param __k    Key to use for finding a possibly existing pair in
+       *                the map.
+       *  @param __obj  Argument used to generate the .second for a pair
+       *                instance.
+       *
+       *  @return  A pair, of which the first element is an iterator that
+       *           points to the possibly inserted pair, and the second is
+       *           a bool that is true if the pair was actually inserted.
+       *
+       *  This function attempts to insert a (key, value) %pair into the %map.
+       *  A %map relies on unique keys and thus a %pair is only inserted if its
+       *  first element (the key) is not already present in the %map.
+       *  If the %pair was already in the %map, the .second of the %pair
+       *  is assigned from __obj.
+       *
+       *  Insertion requires logarithmic time.
+       */
+      template <typename _Obj>
+	pair<iterator, bool>
+	insert_or_assign(const key_type& __k, _Obj&& __obj)
+	{
+	  iterator __i = lower_bound(__k);
+	  if (__i == end() || key_comp()(__k, (*__i).first))
+	    {
+	      __i = emplace_hint(__i, std::piecewise_construct,
+				 std::forward_as_tuple(__k),
+				 std::forward_as_tuple(
+				   std::forward<_Obj>(__obj)));
+	      return {__i, true};
+	    }
+	  (*__i).second = std::forward<_Obj>(__obj);
+	  return {__i, false};
+	}
+
+      // move-capable overload
+      template <typename _Obj>
+	pair<iterator, bool>
+	insert_or_assign(key_type&& __k, _Obj&& __obj)
+	{
+	  iterator __i = lower_bound(__k);
+	  if (__i == end() || key_comp()(__k, (*__i).first))
+	    {
+	      __i = emplace_hint(__i, std::piecewise_construct,
+				 std::forward_as_tuple(std::move(__k)),
+				 std::forward_as_tuple(
+				   std::forward<_Obj>(__obj)));
+	      return {__i, true};
+	    }
+	  (*__i).second = std::forward<_Obj>(__obj);
+	  return {__i, false};
+	}
+
+      /**
+       *  @brief Attempts to insert or assign a std::pair into the %map.
+       *  @param  __hint  An iterator that serves as a hint as to where the
+       *                  pair should be inserted.
+       *  @param __k    Key to use for finding a possibly existing pair in
+       *                the map.
+       *  @param __obj  Argument used to generate the .second for a pair
+       *                instance.
+       *
+       *  @return An iterator that points to the element with key of
+       *           @a __x (may or may not be the %pair passed in).
+       *
+       *  This function attempts to insert a (key, value) %pair into the %map.
+       *  A %map relies on unique keys and thus a %pair is only inserted if its
+       *  first element (the key) is not already present in the %map.
+       *  If the %pair was already in the %map, the .second of the %pair
+       *  is assigned from __obj.
+       *
+       *  Insertion requires logarithmic time.
+       */
+      template <typename _Obj>
+	iterator
+	insert_or_assign(const_iterator __hint,
+			 const key_type& __k, _Obj&& __obj)
+	{
+	  iterator __i;
+	  auto __true_hint = _M_t._M_get_insert_hint_unique_pos(__hint, __k);
+	  if (__true_hint.second)
+	    {
+	      return emplace_hint(iterator(__true_hint.second),
+				  std::piecewise_construct,
+				  std::forward_as_tuple(__k),
+				  std::forward_as_tuple(
+				    std::forward<_Obj>(__obj)));
+	    }
+	  __i = iterator(__true_hint.first);
+	  (*__i).second = std::forward<_Obj>(__obj);
+	  return __i;
+	}
+
+      // move-capable overload
+      template <typename _Obj>
+	iterator
+	insert_or_assign(const_iterator __hint, key_type&& __k, _Obj&& __obj)
+	{
+	  iterator __i;
+	  auto __true_hint = _M_t._M_get_insert_hint_unique_pos(__hint, __k);
+	  if (__true_hint.second)
+	    {
+	      return emplace_hint(iterator(__true_hint.second),
+				  std::piecewise_construct,
+				  std::forward_as_tuple(std::move(__k)),
+				  std::forward_as_tuple(
+				    std::forward<_Obj>(__obj)));
+	    }
+	  __i = iterator(__true_hint.first);
+	  (*__i).second = std::forward<_Obj>(__obj);
+	  return __i;
+	}
+#endif
+
+#if __cplusplus >= 201103L
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // DR 130. Associative erase should return an iterator.
+      /**
+       *  @brief Erases an element from a %map.
+       *  @param  __position  An iterator pointing to the element to be erased.
+       *  @return An iterator pointing to the element immediately following
+       *          @a position prior to the element being erased. If no such
+       *          element exists, end() is returned.
+       *
+       *  This function erases an element, pointed to by the given
+       *  iterator, from a %map.  Note that this function only erases
+       *  the element, and that if the element is itself a pointer,
+       *  the pointed-to memory is not touched in any way.  Managing
+       *  the pointer is the user's responsibility.
+       *
+       *  @{
+       */
+      iterator
+      erase(const_iterator __position)
+      { return _M_t.erase(__position); }
+
+      // LWG 2059
+      _GLIBCXX_ABI_TAG_CXX11
+      iterator
+      erase(iterator __position)
+      { return _M_t.erase(__position); }
+      /// @}
+#else
+      /**
+       *  @brief Erases an element from a %map.
+       *  @param  __position  An iterator pointing to the element to be erased.
+       *
+       *  This function erases an element, pointed to by the given
+       *  iterator, from a %map.  Note that this function only erases
+       *  the element, and that if the element is itself a pointer,
+       *  the pointed-to memory is not touched in any way.  Managing
+       *  the pointer is the user's responsibility.
+       */
+      void
+      erase(iterator __position)
+      { _M_t.erase(__position); }
+#endif
+
+      /**
+       *  @brief Erases elements according to the provided key.
+       *  @param  __x  Key of element to be erased.
+       *  @return  The number of elements erased.
+       *
+       *  This function erases all the elements located by the given key from
+       *  a %map.
+       *  Note that this function only erases the element, and that if
+       *  the element is itself a pointer, the pointed-to memory is not touched
+       *  in any way.  Managing the pointer is the user's responsibility.
+       */
+      size_type
+      erase(const key_type& __x)
+      { return _M_t.erase(__x); }
+
+#if __cplusplus >= 201103L
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // DR 130. Associative erase should return an iterator.
+      /**
+       *  @brief Erases a [first,last) range of elements from a %map.
+       *  @param  __first  Iterator pointing to the start of the range to be
+       *                   erased.
+       *  @param __last Iterator pointing to the end of the range to
+       *                be erased.
+       *  @return The iterator @a __last.
+       *
+       *  This function erases a sequence of elements from a %map.
+       *  Note that this function only erases the element, and that if
+       *  the element is itself a pointer, the pointed-to memory is not touched
+       *  in any way.  Managing the pointer is the user's responsibility.
+       */
+      iterator
+      erase(const_iterator __first, const_iterator __last)
+      { return _M_t.erase(__first, __last); }
+#else
+      /**
+       *  @brief Erases a [__first,__last) range of elements from a %map.
+       *  @param  __first  Iterator pointing to the start of the range to be
+       *                   erased.
+       *  @param __last Iterator pointing to the end of the range to
+       *                be erased.
+       *
+       *  This function erases a sequence of elements from a %map.
+       *  Note that this function only erases the element, and that if
+       *  the element is itself a pointer, the pointed-to memory is not touched
+       *  in any way.  Managing the pointer is the user's responsibility.
+       */
+      void
+      erase(iterator __first, iterator __last)
+      { _M_t.erase(__first, __last); }
+#endif
+
+      /**
+       *  @brief  Swaps data with another %map.
+       *  @param  __x  A %map of the same element and allocator types.
+       *
+       *  This exchanges the elements between two maps in constant
+       *  time.  (It is only swapping a pointer, an integer, and an
+       *  instance of the @c Compare type (which itself is often
+       *  stateless and empty), so it should be quite fast.)  Note
+       *  that the global std::swap() function is specialized such
+       *  that std::swap(m1,m2) will feed to this function.
+       *
+       *  Whether the allocators are swapped depends on the allocator traits.
+       */
+      void
+      swap(map& __x)
+      _GLIBCXX_NOEXCEPT_IF(__is_nothrow_swappable<_Compare>::value)
+      { _M_t.swap(__x._M_t); }
+
+      /**
+       *  Erases all elements in a %map.  Note that this function only
+       *  erases the elements, and that if the elements themselves are
+       *  pointers, the pointed-to memory is not touched in any way.
+       *  Managing the pointer is the user's responsibility.
+       */
+      void
+      clear() _GLIBCXX_NOEXCEPT
+      { _M_t.clear(); }
+
+      // observers
+      /**
+       *  Returns the key comparison object out of which the %map was
+       *  constructed.
+       */
+      key_compare
+      key_comp() const
+      { return _M_t.key_comp(); }
+
+      /**
+       *  Returns a value comparison object, built from the key comparison
+       *  object out of which the %map was constructed.
+       */
+      value_compare
+      value_comp() const
+      { return value_compare(_M_t.key_comp()); }
+
+      // [23.3.1.3] map operations
+
+      ///@{
+      /**
+       *  @brief Tries to locate an element in a %map.
+       *  @param  __x  Key of (key, value) %pair to be located.
+       *  @return  Iterator pointing to sought-after element, or end() if not
+       *           found.
+       *
+       *  This function takes a key and tries to locate the element with which
+       *  the key matches.  If successful the function returns an iterator
+       *  pointing to the sought after %pair.  If unsuccessful it returns the
+       *  past-the-end ( @c end() ) iterator.
+       */
+
+      iterator
+      find(const key_type& __x)
+      { return _M_t.find(__x); }
+
+#if __cplusplus > 201103L
+      template<typename _Kt>
+	auto
+	find(const _Kt& __x) -> decltype(_M_t._M_find_tr(__x))
+	{ return _M_t._M_find_tr(__x); }
+#endif
+      ///@}
+
+      ///@{
+      /**
+       *  @brief Tries to locate an element in a %map.
+       *  @param  __x  Key of (key, value) %pair to be located.
+       *  @return  Read-only (constant) iterator pointing to sought-after
+       *           element, or end() if not found.
+       *
+       *  This function takes a key and tries to locate the element with which
+       *  the key matches.  If successful the function returns a constant
+       *  iterator pointing to the sought after %pair. If unsuccessful it
+       *  returns the past-the-end ( @c end() ) iterator.
+       */
+
+      const_iterator
+      find(const key_type& __x) const
+      { return _M_t.find(__x); }
+
+#if __cplusplus > 201103L
+      template<typename _Kt>
+	auto
+	find(const _Kt& __x) const -> decltype(_M_t._M_find_tr(__x))
+	{ return _M_t._M_find_tr(__x); }
+#endif
+      ///@}
+
+      ///@{
+      /**
+       *  @brief  Finds the number of elements with given key.
+       *  @param  __x  Key of (key, value) pairs to be located.
+       *  @return  Number of elements with specified key.
+       *
+       *  This function only makes sense for multimaps; for map the result will
+       *  either be 0 (not present) or 1 (present).
+       */
+      size_type
+      count(const key_type& __x) const
+      { return _M_t.find(__x) == _M_t.end() ? 0 : 1; }
+
+#if __cplusplus > 201103L
+      template<typename _Kt>
+	auto
+	count(const _Kt& __x) const -> decltype(_M_t._M_count_tr(__x))
+	{ return _M_t._M_count_tr(__x); }
+#endif
+      ///@}
+
+#if __cplusplus > 201703L
+      ///@{
+      /**
+       *  @brief  Finds whether an element with the given key exists.
+       *  @param  __x  Key of (key, value) pairs to be located.
+       *  @return  True if there is an element with the specified key.
+       */
+      bool
+      contains(const key_type& __x) const
+      { return _M_t.find(__x) != _M_t.end(); }
+
+      template<typename _Kt>
+	auto
+	contains(const _Kt& __x) const
+	-> decltype(_M_t._M_find_tr(__x), void(), true)
+	{ return _M_t._M_find_tr(__x) != _M_t.end(); }
+      ///@}
+#endif
+
+      ///@{
+      /**
+       *  @brief Finds the beginning of a subsequence matching given key.
+       *  @param  __x  Key of (key, value) pair to be located.
+       *  @return  Iterator pointing to first element equal to or greater
+       *           than key, or end().
+       *
+       *  This function returns the first element of a subsequence of elements
+       *  that matches the given key.  If unsuccessful it returns an iterator
+       *  pointing to the first element that has a greater value than given key
+       *  or end() if no such element exists.
+       */
+      iterator
+      lower_bound(const key_type& __x)
+      { return _M_t.lower_bound(__x); }
+
+#if __cplusplus > 201103L
+      template<typename _Kt>
+	auto
+	lower_bound(const _Kt& __x)
+	-> decltype(iterator(_M_t._M_lower_bound_tr(__x)))
+	{ return iterator(_M_t._M_lower_bound_tr(__x)); }
+#endif
+      ///@}
+
+      ///@{
+      /**
+       *  @brief Finds the beginning of a subsequence matching given key.
+       *  @param  __x  Key of (key, value) pair to be located.
+       *  @return  Read-only (constant) iterator pointing to first element
+       *           equal to or greater than key, or end().
+       *
+       *  This function returns the first element of a subsequence of elements
+       *  that matches the given key.  If unsuccessful it returns an iterator
+       *  pointing to the first element that has a greater value than given key
+       *  or end() if no such element exists.
+       */
+      const_iterator
+      lower_bound(const key_type& __x) const
+      { return _M_t.lower_bound(__x); }
+
+#if __cplusplus > 201103L
+      template<typename _Kt>
+	auto
+	lower_bound(const _Kt& __x) const
+	-> decltype(const_iterator(_M_t._M_lower_bound_tr(__x)))
+	{ return const_iterator(_M_t._M_lower_bound_tr(__x)); }
+#endif
+      ///@}
+
+      ///@{
+      /**
+       *  @brief Finds the end of a subsequence matching given key.
+       *  @param  __x  Key of (key, value) pair to be located.
+       *  @return Iterator pointing to the first element
+       *          greater than key, or end().
+       */
+      iterator
+      upper_bound(const key_type& __x)
+      { return _M_t.upper_bound(__x); }
+
+#if __cplusplus > 201103L
+      template<typename _Kt>
+	auto
+	upper_bound(const _Kt& __x)
+	-> decltype(iterator(_M_t._M_upper_bound_tr(__x)))
+	{ return iterator(_M_t._M_upper_bound_tr(__x)); }
+#endif
+      ///@}
+
+      ///@{
+      /**
+       *  @brief Finds the end of a subsequence matching given key.
+       *  @param  __x  Key of (key, value) pair to be located.
+       *  @return  Read-only (constant) iterator pointing to first iterator
+       *           greater than key, or end().
+       */
+      const_iterator
+      upper_bound(const key_type& __x) const
+      { return _M_t.upper_bound(__x); }
+
+#if __cplusplus > 201103L
+      template<typename _Kt>
+	auto
+	upper_bound(const _Kt& __x) const
+	-> decltype(const_iterator(_M_t._M_upper_bound_tr(__x)))
+	{ return const_iterator(_M_t._M_upper_bound_tr(__x)); }
+#endif
+      ///@}
+
+      ///@{
+      /**
+       *  @brief Finds a subsequence matching given key.
+       *  @param  __x  Key of (key, value) pairs to be located.
+       *  @return  Pair of iterators that possibly points to the subsequence
+       *           matching given key.
+       *
+       *  This function is equivalent to
+       *  @code
+       *    std::make_pair(c.lower_bound(val),
+       *                   c.upper_bound(val))
+       *  @endcode
+       *  (but is faster than making the calls separately).
+       *
+       *  This function probably only makes sense for multimaps.
+       */
+      std::pair<iterator, iterator>
+      equal_range(const key_type& __x)
+      { return _M_t.equal_range(__x); }
+
+#if __cplusplus > 201103L
+      template<typename _Kt>
+	auto
+	equal_range(const _Kt& __x)
+	-> decltype(pair<iterator, iterator>(_M_t._M_equal_range_tr(__x)))
+	{ return pair<iterator, iterator>(_M_t._M_equal_range_tr(__x)); }
+#endif
+      ///@}
+
+      ///@{
+      /**
+       *  @brief Finds a subsequence matching given key.
+       *  @param  __x  Key of (key, value) pairs to be located.
+       *  @return  Pair of read-only (constant) iterators that possibly points
+       *           to the subsequence matching given key.
+       *
+       *  This function is equivalent to
+       *  @code
+       *    std::make_pair(c.lower_bound(val),
+       *                   c.upper_bound(val))
+       *  @endcode
+       *  (but is faster than making the calls separately).
+       *
+       *  This function probably only makes sense for multimaps.
+       */
+      std::pair<const_iterator, const_iterator>
+      equal_range(const key_type& __x) const
+      { return _M_t.equal_range(__x); }
+
+#if __cplusplus > 201103L
+      template<typename _Kt>
+	auto
+	equal_range(const _Kt& __x) const
+	-> decltype(pair<const_iterator, const_iterator>(
+	      _M_t._M_equal_range_tr(__x)))
+	{
+	  return pair<const_iterator, const_iterator>(
+	      _M_t._M_equal_range_tr(__x));
+	}
+#endif
+      ///@}
+
+      template<typename _K1, typename _T1, typename _C1, typename _A1>
+	friend bool
+	operator==(const map<_K1, _T1, _C1, _A1>&,
+		   const map<_K1, _T1, _C1, _A1>&);
+
+#if __cpp_lib_three_way_comparison
+      template<typename _K1, typename _T1, typename _C1, typename _A1>
+	friend __detail::__synth3way_t<pair<const _K1, _T1>>
+	operator<=>(const map<_K1, _T1, _C1, _A1>&,
+		    const map<_K1, _T1, _C1, _A1>&);
+#else
+      template<typename _K1, typename _T1, typename _C1, typename _A1>
+	friend bool
+	operator<(const map<_K1, _T1, _C1, _A1>&,
+		  const map<_K1, _T1, _C1, _A1>&);
+#endif
+    };
+
+
+#if __cpp_deduction_guides >= 201606
+
+  template<typename _InputIterator,
+	   typename _Compare = less<__iter_key_t<_InputIterator>>,
+	   typename _Allocator = allocator<__iter_to_alloc_t<_InputIterator>>,
+	   typename = _RequireInputIter<_InputIterator>,
+	   typename = _RequireNotAllocator<_Compare>,
+	   typename = _RequireAllocator<_Allocator>>
+    map(_InputIterator, _InputIterator,
+	_Compare = _Compare(), _Allocator = _Allocator())
+    -> map<__iter_key_t<_InputIterator>, __iter_val_t<_InputIterator>,
+	   _Compare, _Allocator>;
+
+  template<typename _Key, typename _Tp, typename _Compare = less<_Key>,
+	   typename _Allocator = allocator<pair<const _Key, _Tp>>,
+	   typename = _RequireNotAllocator<_Compare>,
+	   typename = _RequireAllocator<_Allocator>>
+    map(initializer_list<pair<_Key, _Tp>>,
+	_Compare = _Compare(), _Allocator = _Allocator())
+    -> map<_Key, _Tp, _Compare, _Allocator>;
+
+  template <typename _InputIterator, typename _Allocator,
+	    typename = _RequireInputIter<_InputIterator>,
+	    typename = _RequireAllocator<_Allocator>>
+    map(_InputIterator, _InputIterator, _Allocator)
+    -> map<__iter_key_t<_InputIterator>, __iter_val_t<_InputIterator>,
+	   less<__iter_key_t<_InputIterator>>, _Allocator>;
+
+  template<typename _Key, typename _Tp, typename _Allocator,
+	   typename = _RequireAllocator<_Allocator>>
+    map(initializer_list<pair<_Key, _Tp>>, _Allocator)
+    -> map<_Key, _Tp, less<_Key>, _Allocator>;
+
+#endif // deduction guides
+
+  /**
+   *  @brief  Map equality comparison.
+   *  @param  __x  A %map.
+   *  @param  __y  A %map of the same type as @a x.
+   *  @return  True iff the size and elements of the maps are equal.
+   *
+   *  This is an equivalence relation.  It is linear in the size of the
+   *  maps.  Maps are considered equivalent if their sizes are equal,
+   *  and if corresponding elements compare equal.
+  */
+  template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
+    inline bool
+    operator==(const map<_Key, _Tp, _Compare, _Alloc>& __x,
+	       const map<_Key, _Tp, _Compare, _Alloc>& __y)
+    { return __x._M_t == __y._M_t; }
+
+#if __cpp_lib_three_way_comparison
+  /**
+   *  @brief  Map ordering relation.
+   *  @param  __x  A `map`.
+   *  @param  __y  A `map` of the same type as `x`.
+   *  @return  A value indicating whether `__x` is less than, equal to,
+   *           greater than, or incomparable with `__y`.
+   *
+   *  This is a total ordering relation.  It is linear in the size of the
+   *  maps.  The elements must be comparable with @c <.
+   *
+   *  See `std::lexicographical_compare_three_way()` for how the determination
+   *  is made. This operator is used to synthesize relational operators like
+   *  `<` and `>=` etc.
+  */
+  template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
+    inline __detail::__synth3way_t<pair<const _Key, _Tp>>
+    operator<=>(const map<_Key, _Tp, _Compare, _Alloc>& __x,
+		const map<_Key, _Tp, _Compare, _Alloc>& __y)
+    { return __x._M_t <=> __y._M_t; }
+#else
+  /**
+   *  @brief  Map ordering relation.
+   *  @param  __x  A %map.
+   *  @param  __y  A %map of the same type as @a x.
+   *  @return  True iff @a x is lexicographically less than @a y.
+   *
+   *  This is a total ordering relation.  It is linear in the size of the
+   *  maps.  The elements must be comparable with @c <.
+   *
+   *  See std::lexicographical_compare() for how the determination is made.
+  */
+  template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
+    inline bool
+    operator<(const map<_Key, _Tp, _Compare, _Alloc>& __x,
+	      const map<_Key, _Tp, _Compare, _Alloc>& __y)
+    { return __x._M_t < __y._M_t; }
+
+  /// Based on operator==
+  template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
+    inline bool
+    operator!=(const map<_Key, _Tp, _Compare, _Alloc>& __x,
+	       const map<_Key, _Tp, _Compare, _Alloc>& __y)
+    { return !(__x == __y); }
+
+  /// Based on operator<
+  template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
+    inline bool
+    operator>(const map<_Key, _Tp, _Compare, _Alloc>& __x,
+	      const map<_Key, _Tp, _Compare, _Alloc>& __y)
+    { return __y < __x; }
+
+  /// Based on operator<
+  template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
+    inline bool
+    operator<=(const map<_Key, _Tp, _Compare, _Alloc>& __x,
+	       const map<_Key, _Tp, _Compare, _Alloc>& __y)
+    { return !(__y < __x); }
+
+  /// Based on operator<
+  template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
+    inline bool
+    operator>=(const map<_Key, _Tp, _Compare, _Alloc>& __x,
+	       const map<_Key, _Tp, _Compare, _Alloc>& __y)
+    { return !(__x < __y); }
+#endif // three-way comparison
+
+  /// See std::map::swap().
+  template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
+    inline void
+    swap(map<_Key, _Tp, _Compare, _Alloc>& __x,
+	 map<_Key, _Tp, _Compare, _Alloc>& __y)
+    _GLIBCXX_NOEXCEPT_IF(noexcept(__x.swap(__y)))
+    { __x.swap(__y); }
+
+_GLIBCXX_END_NAMESPACE_CONTAINER
+
+#if __cplusplus > 201402L
+  // Allow std::map access to internals of compatible maps.
+  template<typename _Key, typename _Val, typename _Cmp1, typename _Alloc,
+	   typename _Cmp2>
+    struct
+    _Rb_tree_merge_helper<_GLIBCXX_STD_C::map<_Key, _Val, _Cmp1, _Alloc>,
+			  _Cmp2>
+    {
+    private:
+      friend class _GLIBCXX_STD_C::map<_Key, _Val, _Cmp1, _Alloc>;
+
+      static auto&
+      _S_get_tree(_GLIBCXX_STD_C::map<_Key, _Val, _Cmp2, _Alloc>& __map)
+      { return __map._M_t; }
+
+      static auto&
+      _S_get_tree(_GLIBCXX_STD_C::multimap<_Key, _Val, _Cmp2, _Alloc>& __map)
+      { return __map._M_t; }
+    };
+#endif // C++17
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif /* _STL_MAP_H */
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@@ -0,0 +1,1237 @@
+// Multimap implementation -*- C++ -*-
+
+// Copyright (C) 2001-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/*
+ *
+ * Copyright (c) 1994
+ * Hewlett-Packard Company
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Hewlett-Packard Company makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ *
+ *
+ * Copyright (c) 1996,1997
+ * Silicon Graphics Computer Systems, Inc.
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Silicon Graphics makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ */
+
+/** @file bits/stl_multimap.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{map}
+ */
+
+#ifndef _STL_MULTIMAP_H
+#define _STL_MULTIMAP_H 1
+
+#include <bits/concept_check.h>
+#if __cplusplus >= 201103L
+#include <initializer_list>
+#endif
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+_GLIBCXX_BEGIN_NAMESPACE_CONTAINER
+
+  template <typename _Key, typename _Tp, typename _Compare, typename _Alloc>
+    class map;
+
+  /**
+   *  @brief A standard container made up of (key,value) pairs, which can be
+   *  retrieved based on a key, in logarithmic time.
+   *
+   *  @ingroup associative_containers
+   *
+   *  @tparam _Key  Type of key objects.
+   *  @tparam  _Tp  Type of mapped objects.
+   *  @tparam _Compare  Comparison function object type, defaults to less<_Key>.
+   *  @tparam _Alloc  Allocator type, defaults to
+   *                  allocator<pair<const _Key, _Tp>.
+   *
+   *  Meets the requirements of a <a href="tables.html#65">container</a>, a
+   *  <a href="tables.html#66">reversible container</a>, and an
+   *  <a href="tables.html#69">associative container</a> (using equivalent
+   *  keys).  For a @c multimap<Key,T> the key_type is Key, the mapped_type
+   *  is T, and the value_type is std::pair<const Key,T>.
+   *
+   *  Multimaps support bidirectional iterators.
+   *
+   *  The private tree data is declared exactly the same way for map and
+   *  multimap; the distinction is made entirely in how the tree functions are
+   *  called (*_unique versus *_equal, same as the standard).
+  */
+  template <typename _Key, typename _Tp,
+	    typename _Compare = std::less<_Key>,
+	    typename _Alloc = std::allocator<std::pair<const _Key, _Tp> > >
+    class multimap
+    {
+    public:
+      typedef _Key					key_type;
+      typedef _Tp					mapped_type;
+      typedef std::pair<const _Key, _Tp>		value_type;
+      typedef _Compare					key_compare;
+      typedef _Alloc					allocator_type;
+
+    private:
+#ifdef _GLIBCXX_CONCEPT_CHECKS
+      // concept requirements
+      typedef typename _Alloc::value_type		_Alloc_value_type;
+# if __cplusplus < 201103L
+      __glibcxx_class_requires(_Tp, _SGIAssignableConcept)
+# endif
+      __glibcxx_class_requires4(_Compare, bool, _Key, _Key,
+				_BinaryFunctionConcept)
+      __glibcxx_class_requires2(value_type, _Alloc_value_type, _SameTypeConcept)
+#endif
+
+#if __cplusplus >= 201103L
+#if __cplusplus > 201703L || defined __STRICT_ANSI__
+      static_assert(is_same<typename _Alloc::value_type, value_type>::value,
+	  "std::multimap must have the same value_type as its allocator");
+#endif
+#endif
+
+    public:
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+      class value_compare
+      : public std::binary_function<value_type, value_type, bool>
+      {
+	friend class multimap<_Key, _Tp, _Compare, _Alloc>;
+      protected:
+	_Compare comp;
+
+	value_compare(_Compare __c)
+	: comp(__c) { }
+
+      public:
+	bool operator()(const value_type& __x, const value_type& __y) const
+	{ return comp(__x.first, __y.first); }
+      };
+#pragma GCC diagnostic pop
+
+    private:
+      /// This turns a red-black tree into a [multi]map.
+      typedef typename __gnu_cxx::__alloc_traits<_Alloc>::template
+	rebind<value_type>::other _Pair_alloc_type;
+
+      typedef _Rb_tree<key_type, value_type, _Select1st<value_type>,
+		       key_compare, _Pair_alloc_type> _Rep_type;
+      /// The actual tree structure.
+      _Rep_type _M_t;
+
+      typedef __gnu_cxx::__alloc_traits<_Pair_alloc_type> _Alloc_traits;
+
+    public:
+      // many of these are specified differently in ISO, but the following are
+      // "functionally equivalent"
+      typedef typename _Alloc_traits::pointer		 pointer;
+      typedef typename _Alloc_traits::const_pointer	 const_pointer;
+      typedef typename _Alloc_traits::reference		 reference;
+      typedef typename _Alloc_traits::const_reference	 const_reference;
+      typedef typename _Rep_type::iterator		 iterator;
+      typedef typename _Rep_type::const_iterator	 const_iterator;
+      typedef typename _Rep_type::size_type		 size_type;
+      typedef typename _Rep_type::difference_type	 difference_type;
+      typedef typename _Rep_type::reverse_iterator	 reverse_iterator;
+      typedef typename _Rep_type::const_reverse_iterator const_reverse_iterator;
+
+#if __cplusplus > 201402L
+      using node_type = typename _Rep_type::node_type;
+#endif
+
+      // [23.3.2] construct/copy/destroy
+      // (get_allocator() is also listed in this section)
+
+      /**
+       *  @brief  Default constructor creates no elements.
+       */
+#if __cplusplus < 201103L
+      multimap() : _M_t() { }
+#else
+      multimap() = default;
+#endif
+
+      /**
+       *  @brief  Creates a %multimap with no elements.
+       *  @param  __comp  A comparison object.
+       *  @param  __a  An allocator object.
+       */
+      explicit
+      multimap(const _Compare& __comp,
+	       const allocator_type& __a = allocator_type())
+      : _M_t(__comp, _Pair_alloc_type(__a)) { }
+
+      /**
+       *  @brief  %Multimap copy constructor.
+       *
+       *  Whether the allocator is copied depends on the allocator traits.
+       */
+#if __cplusplus < 201103L
+      multimap(const multimap& __x)
+      : _M_t(__x._M_t) { }
+#else
+      multimap(const multimap&) = default;
+
+      /**
+       *  @brief  %Multimap move constructor.
+       *
+       *  The newly-created %multimap contains the exact contents of the
+       *  moved instance. The moved instance is a valid, but unspecified
+       *  %multimap.
+       */
+      multimap(multimap&&) = default;
+
+      /**
+       *  @brief  Builds a %multimap from an initializer_list.
+       *  @param  __l  An initializer_list.
+       *  @param  __comp  A comparison functor.
+       *  @param  __a  An allocator object.
+       *
+       *  Create a %multimap consisting of copies of the elements from
+       *  the initializer_list.  This is linear in N if the list is already
+       *  sorted, and NlogN otherwise (where N is @a __l.size()).
+       */
+      multimap(initializer_list<value_type> __l,
+	       const _Compare& __comp = _Compare(),
+	       const allocator_type& __a = allocator_type())
+      : _M_t(__comp, _Pair_alloc_type(__a))
+      { _M_t._M_insert_range_equal(__l.begin(), __l.end()); }
+
+      /// Allocator-extended default constructor.
+      explicit
+      multimap(const allocator_type& __a)
+      : _M_t(_Pair_alloc_type(__a)) { }
+
+      /// Allocator-extended copy constructor.
+      multimap(const multimap& __m,
+	       const __type_identity_t<allocator_type>& __a)
+      : _M_t(__m._M_t, _Pair_alloc_type(__a)) { }
+
+      /// Allocator-extended move constructor.
+      multimap(multimap&& __m, const __type_identity_t<allocator_type>& __a)
+      noexcept(is_nothrow_copy_constructible<_Compare>::value
+	       && _Alloc_traits::_S_always_equal())
+      : _M_t(std::move(__m._M_t), _Pair_alloc_type(__a)) { }
+
+      /// Allocator-extended initialier-list constructor.
+      multimap(initializer_list<value_type> __l, const allocator_type& __a)
+      : _M_t(_Pair_alloc_type(__a))
+      { _M_t._M_insert_range_equal(__l.begin(), __l.end()); }
+
+      /// Allocator-extended range constructor.
+      template<typename _InputIterator>
+	multimap(_InputIterator __first, _InputIterator __last,
+		 const allocator_type& __a)
+	: _M_t(_Pair_alloc_type(__a))
+	{ _M_t._M_insert_range_equal(__first, __last); }
+#endif
+
+      /**
+       *  @brief  Builds a %multimap from a range.
+       *  @param  __first  An input iterator.
+       *  @param  __last  An input iterator.
+       *
+       *  Create a %multimap consisting of copies of the elements from
+       *  [__first,__last).  This is linear in N if the range is already sorted,
+       *  and NlogN otherwise (where N is distance(__first,__last)).
+       */
+      template<typename _InputIterator>
+	multimap(_InputIterator __first, _InputIterator __last)
+	: _M_t()
+	{ _M_t._M_insert_range_equal(__first, __last); }
+
+      /**
+       *  @brief  Builds a %multimap from a range.
+       *  @param  __first  An input iterator.
+       *  @param  __last  An input iterator.
+       *  @param  __comp  A comparison functor.
+       *  @param  __a  An allocator object.
+       *
+       *  Create a %multimap consisting of copies of the elements from
+       *  [__first,__last).  This is linear in N if the range is already sorted,
+       *  and NlogN otherwise (where N is distance(__first,__last)).
+       */
+      template<typename _InputIterator>
+	multimap(_InputIterator __first, _InputIterator __last,
+		 const _Compare& __comp,
+		 const allocator_type& __a = allocator_type())
+	: _M_t(__comp, _Pair_alloc_type(__a))
+	{ _M_t._M_insert_range_equal(__first, __last); }
+
+#if __cplusplus >= 201103L
+      /**
+       *  The dtor only erases the elements, and note that if the elements
+       *  themselves are pointers, the pointed-to memory is not touched in any
+       *  way. Managing the pointer is the user's responsibility.
+       */
+      ~multimap() = default;
+#endif
+
+      /**
+       *  @brief  %Multimap assignment operator.
+       *
+       *  Whether the allocator is copied depends on the allocator traits.
+       */
+#if __cplusplus < 201103L
+      multimap&
+      operator=(const multimap& __x)
+      {
+	_M_t = __x._M_t;
+	return *this;
+      }
+#else
+      multimap&
+      operator=(const multimap&) = default;
+
+      /// Move assignment operator.
+      multimap&
+      operator=(multimap&&) = default;
+
+      /**
+       *  @brief  %Multimap list assignment operator.
+       *  @param  __l  An initializer_list.
+       *
+       *  This function fills a %multimap with copies of the elements
+       *  in the initializer list @a __l.
+       *
+       *  Note that the assignment completely changes the %multimap and
+       *  that the resulting %multimap's size is the same as the number
+       *  of elements assigned.
+       */
+      multimap&
+      operator=(initializer_list<value_type> __l)
+      {
+	_M_t._M_assign_equal(__l.begin(), __l.end());
+	return *this;
+      }
+#endif
+
+      /// Get a copy of the memory allocation object.
+      allocator_type
+      get_allocator() const _GLIBCXX_NOEXCEPT
+      { return allocator_type(_M_t.get_allocator()); }
+
+      // iterators
+      /**
+       *  Returns a read/write iterator that points to the first pair in the
+       *  %multimap.  Iteration is done in ascending order according to the
+       *  keys.
+       */
+      iterator
+      begin() _GLIBCXX_NOEXCEPT
+      { return _M_t.begin(); }
+
+      /**
+       *  Returns a read-only (constant) iterator that points to the first pair
+       *  in the %multimap.  Iteration is done in ascending order according to
+       *  the keys.
+       */
+      const_iterator
+      begin() const _GLIBCXX_NOEXCEPT
+      { return _M_t.begin(); }
+
+      /**
+       *  Returns a read/write iterator that points one past the last pair in
+       *  the %multimap.  Iteration is done in ascending order according to the
+       *  keys.
+       */
+      iterator
+      end() _GLIBCXX_NOEXCEPT
+      { return _M_t.end(); }
+
+      /**
+       *  Returns a read-only (constant) iterator that points one past the last
+       *  pair in the %multimap.  Iteration is done in ascending order according
+       *  to the keys.
+       */
+      const_iterator
+      end() const _GLIBCXX_NOEXCEPT
+      { return _M_t.end(); }
+
+      /**
+       *  Returns a read/write reverse iterator that points to the last pair in
+       *  the %multimap.  Iteration is done in descending order according to the
+       *  keys.
+       */
+      reverse_iterator
+      rbegin() _GLIBCXX_NOEXCEPT
+      { return _M_t.rbegin(); }
+
+      /**
+       *  Returns a read-only (constant) reverse iterator that points to the
+       *  last pair in the %multimap.  Iteration is done in descending order
+       *  according to the keys.
+       */
+      const_reverse_iterator
+      rbegin() const _GLIBCXX_NOEXCEPT
+      { return _M_t.rbegin(); }
+
+      /**
+       *  Returns a read/write reverse iterator that points to one before the
+       *  first pair in the %multimap.  Iteration is done in descending order
+       *  according to the keys.
+       */
+      reverse_iterator
+      rend() _GLIBCXX_NOEXCEPT
+      { return _M_t.rend(); }
+
+      /**
+       *  Returns a read-only (constant) reverse iterator that points to one
+       *  before the first pair in the %multimap.  Iteration is done in
+       *  descending order according to the keys.
+       */
+      const_reverse_iterator
+      rend() const _GLIBCXX_NOEXCEPT
+      { return _M_t.rend(); }
+
+#if __cplusplus >= 201103L
+      /**
+       *  Returns a read-only (constant) iterator that points to the first pair
+       *  in the %multimap.  Iteration is done in ascending order according to
+       *  the keys.
+       */
+      const_iterator
+      cbegin() const noexcept
+      { return _M_t.begin(); }
+
+      /**
+       *  Returns a read-only (constant) iterator that points one past the last
+       *  pair in the %multimap.  Iteration is done in ascending order according
+       *  to the keys.
+       */
+      const_iterator
+      cend() const noexcept
+      { return _M_t.end(); }
+
+      /**
+       *  Returns a read-only (constant) reverse iterator that points to the
+       *  last pair in the %multimap.  Iteration is done in descending order
+       *  according to the keys.
+       */
+      const_reverse_iterator
+      crbegin() const noexcept
+      { return _M_t.rbegin(); }
+
+      /**
+       *  Returns a read-only (constant) reverse iterator that points to one
+       *  before the first pair in the %multimap.  Iteration is done in
+       *  descending order according to the keys.
+       */
+      const_reverse_iterator
+      crend() const noexcept
+      { return _M_t.rend(); }
+#endif
+
+      // capacity
+      /** Returns true if the %multimap is empty.  */
+      _GLIBCXX_NODISCARD bool
+      empty() const _GLIBCXX_NOEXCEPT
+      { return _M_t.empty(); }
+
+      /** Returns the size of the %multimap.  */
+      size_type
+      size() const _GLIBCXX_NOEXCEPT
+      { return _M_t.size(); }
+
+      /** Returns the maximum size of the %multimap.  */
+      size_type
+      max_size() const _GLIBCXX_NOEXCEPT
+      { return _M_t.max_size(); }
+
+      // modifiers
+#if __cplusplus >= 201103L
+      /**
+       *  @brief Build and insert a std::pair into the %multimap.
+       *
+       *  @param __args  Arguments used to generate a new pair instance (see
+       *	        std::piecewise_contruct for passing arguments to each
+       *	        part of the pair constructor).
+       *
+       *  @return An iterator that points to the inserted (key,value) pair.
+       *
+       *  This function builds and inserts a (key, value) %pair into the
+       *  %multimap.
+       *  Contrary to a std::map the %multimap does not rely on unique keys and
+       *  thus multiple pairs with the same key can be inserted.
+       *
+       *  Insertion requires logarithmic time.
+       */
+      template<typename... _Args>
+	iterator
+	emplace(_Args&&... __args)
+	{ return _M_t._M_emplace_equal(std::forward<_Args>(__args)...); }
+
+      /**
+       *  @brief Builds and inserts a std::pair into the %multimap.
+       *
+       *  @param  __pos  An iterator that serves as a hint as to where the pair
+       *                should be inserted.
+       *  @param  __args  Arguments used to generate a new pair instance (see
+       *	         std::piecewise_contruct for passing arguments to each
+       *	         part of the pair constructor).
+       *  @return An iterator that points to the inserted (key,value) pair.
+       *
+       *  This function inserts a (key, value) pair into the %multimap.
+       *  Contrary to a std::map the %multimap does not rely on unique keys and
+       *  thus multiple pairs with the same key can be inserted.
+       *  Note that the first parameter is only a hint and can potentially
+       *  improve the performance of the insertion process.  A bad hint would
+       *  cause no gains in efficiency.
+       *
+       *  For more on @a hinting, see:
+       *  https://gcc.gnu.org/onlinedocs/libstdc++/manual/associative.html#containers.associative.insert_hints
+       *
+       *  Insertion requires logarithmic time (if the hint is not taken).
+       */
+      template<typename... _Args>
+	iterator
+	emplace_hint(const_iterator __pos, _Args&&... __args)
+	{
+	  return _M_t._M_emplace_hint_equal(__pos,
+					    std::forward<_Args>(__args)...);
+	}
+#endif
+
+      /**
+       *  @brief Inserts a std::pair into the %multimap.
+       *  @param  __x  Pair to be inserted (see std::make_pair for easy creation
+       *             of pairs).
+       *  @return An iterator that points to the inserted (key,value) pair.
+       *
+       *  This function inserts a (key, value) pair into the %multimap.
+       *  Contrary to a std::map the %multimap does not rely on unique keys and
+       *  thus multiple pairs with the same key can be inserted.
+       *
+       *  Insertion requires logarithmic time.
+       *  @{
+       */
+      iterator
+      insert(const value_type& __x)
+      { return _M_t._M_insert_equal(__x); }
+
+#if __cplusplus >= 201103L
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 2354. Unnecessary copying when inserting into maps with braced-init
+      iterator
+      insert(value_type&& __x)
+      { return _M_t._M_insert_equal(std::move(__x)); }
+
+      template<typename _Pair>
+	__enable_if_t<is_constructible<value_type, _Pair>::value, iterator>
+	insert(_Pair&& __x)
+	{ return _M_t._M_emplace_equal(std::forward<_Pair>(__x)); }
+#endif
+      /// @}
+
+      /**
+       *  @brief Inserts a std::pair into the %multimap.
+       *  @param  __position  An iterator that serves as a hint as to where the
+       *                      pair should be inserted.
+       *  @param  __x  Pair to be inserted (see std::make_pair for easy creation
+       *               of pairs).
+       *  @return An iterator that points to the inserted (key,value) pair.
+       *
+       *  This function inserts a (key, value) pair into the %multimap.
+       *  Contrary to a std::map the %multimap does not rely on unique keys and
+       *  thus multiple pairs with the same key can be inserted.
+       *  Note that the first parameter is only a hint and can potentially
+       *  improve the performance of the insertion process.  A bad hint would
+       *  cause no gains in efficiency.
+       *
+       *  For more on @a hinting, see:
+       *  https://gcc.gnu.org/onlinedocs/libstdc++/manual/associative.html#containers.associative.insert_hints
+       *
+       *  Insertion requires logarithmic time (if the hint is not taken).
+       * @{
+       */
+      iterator
+#if __cplusplus >= 201103L
+      insert(const_iterator __position, const value_type& __x)
+#else
+      insert(iterator __position, const value_type& __x)
+#endif
+      { return _M_t._M_insert_equal_(__position, __x); }
+
+#if __cplusplus >= 201103L
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 2354. Unnecessary copying when inserting into maps with braced-init
+      iterator
+      insert(const_iterator __position, value_type&& __x)
+      { return _M_t._M_insert_equal_(__position, std::move(__x)); }
+
+      template<typename _Pair>
+	__enable_if_t<is_constructible<value_type, _Pair&&>::value, iterator>
+	insert(const_iterator __position, _Pair&& __x)
+	{
+	  return _M_t._M_emplace_hint_equal(__position,
+					    std::forward<_Pair>(__x));
+	}
+#endif
+      /// @}
+
+      /**
+       *  @brief A template function that attempts to insert a range
+       *  of elements.
+       *  @param  __first  Iterator pointing to the start of the range to be
+       *                   inserted.
+       *  @param  __last  Iterator pointing to the end of the range.
+       *
+       *  Complexity similar to that of the range constructor.
+       */
+      template<typename _InputIterator>
+	void
+	insert(_InputIterator __first, _InputIterator __last)
+	{ _M_t._M_insert_range_equal(__first, __last); }
+
+#if __cplusplus >= 201103L
+      /**
+       *  @brief Attempts to insert a list of std::pairs into the %multimap.
+       *  @param  __l  A std::initializer_list<value_type> of pairs to be
+       *               inserted.
+       *
+       *  Complexity similar to that of the range constructor.
+       */
+      void
+      insert(initializer_list<value_type> __l)
+      { this->insert(__l.begin(), __l.end()); }
+#endif
+
+#if __cplusplus > 201402L
+      /// Extract a node.
+      node_type
+      extract(const_iterator __pos)
+      {
+	__glibcxx_assert(__pos != end());
+	return _M_t.extract(__pos);
+      }
+
+      /// Extract a node.
+      node_type
+      extract(const key_type& __x)
+      { return _M_t.extract(__x); }
+
+      /// Re-insert an extracted node.
+      iterator
+      insert(node_type&& __nh)
+      { return _M_t._M_reinsert_node_equal(std::move(__nh)); }
+
+      /// Re-insert an extracted node.
+      iterator
+      insert(const_iterator __hint, node_type&& __nh)
+      { return _M_t._M_reinsert_node_hint_equal(__hint, std::move(__nh)); }
+
+      template<typename, typename>
+	friend struct std::_Rb_tree_merge_helper;
+
+      template<typename _Cmp2>
+	void
+	merge(multimap<_Key, _Tp, _Cmp2, _Alloc>& __source)
+	{
+	  using _Merge_helper = _Rb_tree_merge_helper<multimap, _Cmp2>;
+	  _M_t._M_merge_equal(_Merge_helper::_S_get_tree(__source));
+	}
+
+      template<typename _Cmp2>
+	void
+	merge(multimap<_Key, _Tp, _Cmp2, _Alloc>&& __source)
+	{ merge(__source); }
+
+      template<typename _Cmp2>
+	void
+	merge(map<_Key, _Tp, _Cmp2, _Alloc>& __source)
+	{
+	  using _Merge_helper = _Rb_tree_merge_helper<multimap, _Cmp2>;
+	  _M_t._M_merge_equal(_Merge_helper::_S_get_tree(__source));
+	}
+
+      template<typename _Cmp2>
+	void
+	merge(map<_Key, _Tp, _Cmp2, _Alloc>&& __source)
+	{ merge(__source); }
+#endif // C++17
+
+#if __cplusplus >= 201103L
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // DR 130. Associative erase should return an iterator.
+      /**
+       *  @brief Erases an element from a %multimap.
+       *  @param  __position  An iterator pointing to the element to be erased.
+       *  @return An iterator pointing to the element immediately following
+       *          @a position prior to the element being erased. If no such
+       *          element exists, end() is returned.
+       *
+       *  This function erases an element, pointed to by the given iterator,
+       *  from a %multimap.  Note that this function only erases the element,
+       *  and that if the element is itself a pointer, the pointed-to memory is
+       *  not touched in any way.  Managing the pointer is the user's
+       *  responsibility.
+       *
+       * @{
+       */
+      iterator
+      erase(const_iterator __position)
+      { return _M_t.erase(__position); }
+
+      // LWG 2059.
+      _GLIBCXX_ABI_TAG_CXX11
+      iterator
+      erase(iterator __position)
+      { return _M_t.erase(__position); }
+      /// @}
+#else
+      /**
+       *  @brief Erases an element from a %multimap.
+       *  @param  __position  An iterator pointing to the element to be erased.
+       *
+       *  This function erases an element, pointed to by the given iterator,
+       *  from a %multimap.  Note that this function only erases the element,
+       *  and that if the element is itself a pointer, the pointed-to memory is
+       *  not touched in any way.  Managing the pointer is the user's
+       *  responsibility.
+       */
+      void
+      erase(iterator __position)
+      { _M_t.erase(__position); }
+#endif
+
+      /**
+       *  @brief Erases elements according to the provided key.
+       *  @param  __x  Key of element to be erased.
+       *  @return  The number of elements erased.
+       *
+       *  This function erases all elements located by the given key from a
+       *  %multimap.
+       *  Note that this function only erases the element, and that if
+       *  the element is itself a pointer, the pointed-to memory is not touched
+       *  in any way.  Managing the pointer is the user's responsibility.
+       */
+      size_type
+      erase(const key_type& __x)
+      { return _M_t.erase(__x); }
+
+#if __cplusplus >= 201103L
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // DR 130. Associative erase should return an iterator.
+      /**
+       *  @brief Erases a [first,last) range of elements from a %multimap.
+       *  @param  __first  Iterator pointing to the start of the range to be
+       *                   erased.
+       *  @param __last Iterator pointing to the end of the range to be
+       *                erased .
+       *  @return The iterator @a __last.
+       *
+       *  This function erases a sequence of elements from a %multimap.
+       *  Note that this function only erases the elements, and that if
+       *  the elements themselves are pointers, the pointed-to memory is not
+       *  touched in any way.  Managing the pointer is the user's
+       *  responsibility.
+       */
+      iterator
+      erase(const_iterator __first, const_iterator __last)
+      { return _M_t.erase(__first, __last); }
+#else
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // DR 130. Associative erase should return an iterator.
+      /**
+       *  @brief Erases a [first,last) range of elements from a %multimap.
+       *  @param  __first  Iterator pointing to the start of the range to be
+       *                 erased.
+       *  @param __last Iterator pointing to the end of the range to
+       *                be erased.
+       *
+       *  This function erases a sequence of elements from a %multimap.
+       *  Note that this function only erases the elements, and that if
+       *  the elements themselves are pointers, the pointed-to memory is not
+       *  touched in any way.  Managing the pointer is the user's
+       *  responsibility.
+       */
+      void
+      erase(iterator __first, iterator __last)
+      { _M_t.erase(__first, __last); }
+#endif
+
+      /**
+       *  @brief  Swaps data with another %multimap.
+       *  @param  __x  A %multimap of the same element and allocator types.
+       *
+       *  This exchanges the elements between two multimaps in constant time.
+       *  (It is only swapping a pointer, an integer, and an instance of
+       *  the @c Compare type (which itself is often stateless and empty), so it
+       *  should be quite fast.)
+       *  Note that the global std::swap() function is specialized such that
+       *  std::swap(m1,m2) will feed to this function.
+       *
+       *  Whether the allocators are swapped depends on the allocator traits.
+       */
+      void
+      swap(multimap& __x)
+      _GLIBCXX_NOEXCEPT_IF(__is_nothrow_swappable<_Compare>::value)
+      { _M_t.swap(__x._M_t); }
+
+      /**
+       *  Erases all elements in a %multimap.  Note that this function only
+       *  erases the elements, and that if the elements themselves are pointers,
+       *  the pointed-to memory is not touched in any way.  Managing the pointer
+       *  is the user's responsibility.
+       */
+      void
+      clear() _GLIBCXX_NOEXCEPT
+      { _M_t.clear(); }
+
+      // observers
+      /**
+       *  Returns the key comparison object out of which the %multimap
+       *  was constructed.
+       */
+      key_compare
+      key_comp() const
+      { return _M_t.key_comp(); }
+
+      /**
+       *  Returns a value comparison object, built from the key comparison
+       *  object out of which the %multimap was constructed.
+       */
+      value_compare
+      value_comp() const
+      { return value_compare(_M_t.key_comp()); }
+
+      // multimap operations
+
+      ///@{
+      /**
+       *  @brief Tries to locate an element in a %multimap.
+       *  @param  __x  Key of (key, value) pair to be located.
+       *  @return  Iterator pointing to sought-after element,
+       *           or end() if not found.
+       *
+       *  This function takes a key and tries to locate the element with which
+       *  the key matches.  If successful the function returns an iterator
+       *  pointing to the sought after %pair.  If unsuccessful it returns the
+       *  past-the-end ( @c end() ) iterator.
+       */
+      iterator
+      find(const key_type& __x)
+      { return _M_t.find(__x); }
+
+#if __cplusplus > 201103L
+      template<typename _Kt>
+	auto
+	find(const _Kt& __x) -> decltype(_M_t._M_find_tr(__x))
+	{ return _M_t._M_find_tr(__x); }
+#endif
+      ///@}
+
+      ///@{
+      /**
+       *  @brief Tries to locate an element in a %multimap.
+       *  @param  __x  Key of (key, value) pair to be located.
+       *  @return  Read-only (constant) iterator pointing to sought-after
+       *           element, or end() if not found.
+       *
+       *  This function takes a key and tries to locate the element with which
+       *  the key matches.  If successful the function returns a constant
+       *  iterator pointing to the sought after %pair.  If unsuccessful it
+       *  returns the past-the-end ( @c end() ) iterator.
+       */
+      const_iterator
+      find(const key_type& __x) const
+      { return _M_t.find(__x); }
+
+#if __cplusplus > 201103L
+      template<typename _Kt>
+	auto
+	find(const _Kt& __x) const -> decltype(_M_t._M_find_tr(__x))
+	{ return _M_t._M_find_tr(__x); }
+#endif
+      ///@}
+
+      ///@{
+      /**
+       *  @brief Finds the number of elements with given key.
+       *  @param  __x  Key of (key, value) pairs to be located.
+       *  @return Number of elements with specified key.
+       */
+      size_type
+      count(const key_type& __x) const
+      { return _M_t.count(__x); }
+
+#if __cplusplus > 201103L
+      template<typename _Kt>
+	auto
+	count(const _Kt& __x) const -> decltype(_M_t._M_count_tr(__x))
+	{ return _M_t._M_count_tr(__x); }
+#endif
+      ///@}
+
+#if __cplusplus > 201703L
+      ///@{
+      /**
+       *  @brief  Finds whether an element with the given key exists.
+       *  @param  __x  Key of (key, value) pairs to be located.
+       *  @return  True if there is any element with the specified key.
+       */
+      bool
+      contains(const key_type& __x) const
+      { return _M_t.find(__x) != _M_t.end(); }
+
+      template<typename _Kt>
+	auto
+	contains(const _Kt& __x) const
+	-> decltype(_M_t._M_find_tr(__x), void(), true)
+	{ return _M_t._M_find_tr(__x) != _M_t.end(); }
+      ///@}
+#endif
+
+      ///@{
+      /**
+       *  @brief Finds the beginning of a subsequence matching given key.
+       *  @param  __x  Key of (key, value) pair to be located.
+       *  @return  Iterator pointing to first element equal to or greater
+       *           than key, or end().
+       *
+       *  This function returns the first element of a subsequence of elements
+       *  that matches the given key.  If unsuccessful it returns an iterator
+       *  pointing to the first element that has a greater value than given key
+       *  or end() if no such element exists.
+       */
+      iterator
+      lower_bound(const key_type& __x)
+      { return _M_t.lower_bound(__x); }
+
+#if __cplusplus > 201103L
+      template<typename _Kt>
+	auto
+	lower_bound(const _Kt& __x)
+	-> decltype(iterator(_M_t._M_lower_bound_tr(__x)))
+	{ return iterator(_M_t._M_lower_bound_tr(__x)); }
+#endif
+      ///@}
+
+      ///@{
+      /**
+       *  @brief Finds the beginning of a subsequence matching given key.
+       *  @param  __x  Key of (key, value) pair to be located.
+       *  @return  Read-only (constant) iterator pointing to first element
+       *           equal to or greater than key, or end().
+       *
+       *  This function returns the first element of a subsequence of
+       *  elements that matches the given key.  If unsuccessful the
+       *  iterator will point to the next greatest element or, if no
+       *  such greater element exists, to end().
+       */
+      const_iterator
+      lower_bound(const key_type& __x) const
+      { return _M_t.lower_bound(__x); }
+
+#if __cplusplus > 201103L
+      template<typename _Kt>
+	auto
+	lower_bound(const _Kt& __x) const
+	-> decltype(const_iterator(_M_t._M_lower_bound_tr(__x)))
+	{ return const_iterator(_M_t._M_lower_bound_tr(__x)); }
+#endif
+      ///@}
+
+      ///@{
+      /**
+       *  @brief Finds the end of a subsequence matching given key.
+       *  @param  __x  Key of (key, value) pair to be located.
+       *  @return Iterator pointing to the first element
+       *          greater than key, or end().
+       */
+      iterator
+      upper_bound(const key_type& __x)
+      { return _M_t.upper_bound(__x); }
+
+#if __cplusplus > 201103L
+      template<typename _Kt>
+	auto
+	upper_bound(const _Kt& __x)
+	-> decltype(iterator(_M_t._M_upper_bound_tr(__x)))
+	{ return iterator(_M_t._M_upper_bound_tr(__x)); }
+#endif
+      ///@}
+
+      ///@{
+      /**
+       *  @brief Finds the end of a subsequence matching given key.
+       *  @param  __x  Key of (key, value) pair to be located.
+       *  @return  Read-only (constant) iterator pointing to first iterator
+       *           greater than key, or end().
+       */
+      const_iterator
+      upper_bound(const key_type& __x) const
+      { return _M_t.upper_bound(__x); }
+
+#if __cplusplus > 201103L
+      template<typename _Kt>
+	auto
+	upper_bound(const _Kt& __x) const
+	-> decltype(const_iterator(_M_t._M_upper_bound_tr(__x)))
+	{ return const_iterator(_M_t._M_upper_bound_tr(__x)); }
+#endif
+      ///@}
+
+      ///@{
+      /**
+       *  @brief Finds a subsequence matching given key.
+       *  @param  __x  Key of (key, value) pairs to be located.
+       *  @return  Pair of iterators that possibly points to the subsequence
+       *           matching given key.
+       *
+       *  This function is equivalent to
+       *  @code
+       *    std::make_pair(c.lower_bound(val),
+       *                   c.upper_bound(val))
+       *  @endcode
+       *  (but is faster than making the calls separately).
+       */
+      std::pair<iterator, iterator>
+      equal_range(const key_type& __x)
+      { return _M_t.equal_range(__x); }
+
+#if __cplusplus > 201103L
+      template<typename _Kt>
+	auto
+	equal_range(const _Kt& __x)
+	-> decltype(pair<iterator, iterator>(_M_t._M_equal_range_tr(__x)))
+	{ return pair<iterator, iterator>(_M_t._M_equal_range_tr(__x)); }
+#endif
+      ///@}
+
+      ///@{
+      /**
+       *  @brief Finds a subsequence matching given key.
+       *  @param  __x  Key of (key, value) pairs to be located.
+       *  @return  Pair of read-only (constant) iterators that possibly points
+       *           to the subsequence matching given key.
+       *
+       *  This function is equivalent to
+       *  @code
+       *    std::make_pair(c.lower_bound(val),
+       *                   c.upper_bound(val))
+       *  @endcode
+       *  (but is faster than making the calls separately).
+       */
+      std::pair<const_iterator, const_iterator>
+      equal_range(const key_type& __x) const
+      { return _M_t.equal_range(__x); }
+
+#if __cplusplus > 201103L
+      template<typename _Kt>
+	auto
+	equal_range(const _Kt& __x) const
+	-> decltype(pair<const_iterator, const_iterator>(
+	      _M_t._M_equal_range_tr(__x)))
+	{
+	  return pair<const_iterator, const_iterator>(
+	      _M_t._M_equal_range_tr(__x));
+	}
+#endif
+      ///@}
+
+      template<typename _K1, typename _T1, typename _C1, typename _A1>
+	friend bool
+	operator==(const multimap<_K1, _T1, _C1, _A1>&,
+		   const multimap<_K1, _T1, _C1, _A1>&);
+
+#if __cpp_lib_three_way_comparison
+      template<typename _K1, typename _T1, typename _C1, typename _A1>
+	friend __detail::__synth3way_t<pair<const _K1, _T1>>
+	operator<=>(const multimap<_K1, _T1, _C1, _A1>&,
+		    const multimap<_K1, _T1, _C1, _A1>&);
+#else
+      template<typename _K1, typename _T1, typename _C1, typename _A1>
+	friend bool
+	operator<(const multimap<_K1, _T1, _C1, _A1>&,
+		  const multimap<_K1, _T1, _C1, _A1>&);
+#endif
+  };
+
+#if __cpp_deduction_guides >= 201606
+
+  template<typename _InputIterator,
+	   typename _Compare = less<__iter_key_t<_InputIterator>>,
+	   typename _Allocator = allocator<__iter_to_alloc_t<_InputIterator>>,
+	   typename = _RequireInputIter<_InputIterator>,
+	   typename = _RequireNotAllocator<_Compare>,
+	   typename = _RequireAllocator<_Allocator>>
+    multimap(_InputIterator, _InputIterator,
+	     _Compare = _Compare(), _Allocator = _Allocator())
+    -> multimap<__iter_key_t<_InputIterator>, __iter_val_t<_InputIterator>,
+		_Compare, _Allocator>;
+
+  template<typename _Key, typename _Tp, typename _Compare = less<_Key>,
+	   typename _Allocator = allocator<pair<const _Key, _Tp>>,
+	   typename = _RequireNotAllocator<_Compare>,
+	   typename = _RequireAllocator<_Allocator>>
+    multimap(initializer_list<pair<_Key, _Tp>>,
+	     _Compare = _Compare(), _Allocator = _Allocator())
+    -> multimap<_Key, _Tp, _Compare, _Allocator>;
+
+  template<typename _InputIterator, typename _Allocator,
+	   typename = _RequireInputIter<_InputIterator>,
+	   typename = _RequireAllocator<_Allocator>>
+    multimap(_InputIterator, _InputIterator, _Allocator)
+    -> multimap<__iter_key_t<_InputIterator>, __iter_val_t<_InputIterator>,
+		less<__iter_key_t<_InputIterator>>, _Allocator>;
+
+  template<typename _Key, typename _Tp, typename _Allocator,
+	   typename = _RequireAllocator<_Allocator>>
+    multimap(initializer_list<pair<_Key, _Tp>>, _Allocator)
+    -> multimap<_Key, _Tp, less<_Key>, _Allocator>;
+
+#endif // deduction guides
+
+  /**
+   *  @brief  Multimap equality comparison.
+   *  @param  __x  A %multimap.
+   *  @param  __y  A %multimap of the same type as @a __x.
+   *  @return  True iff the size and elements of the maps are equal.
+   *
+   *  This is an equivalence relation.  It is linear in the size of the
+   *  multimaps.  Multimaps are considered equivalent if their sizes are equal,
+   *  and if corresponding elements compare equal.
+  */
+  template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
+    inline bool
+    operator==(const multimap<_Key, _Tp, _Compare, _Alloc>& __x,
+	       const multimap<_Key, _Tp, _Compare, _Alloc>& __y)
+    { return __x._M_t == __y._M_t; }
+
+#if __cpp_lib_three_way_comparison
+  /**
+   *  @brief  Multimap ordering relation.
+   *  @param  __x  A `multimap`.
+   *  @param  __y  A `multimap` of the same type as `x`.
+   *  @return  A value indicating whether `__x` is less than, equal to,
+   *           greater than, or incomparable with `__y`.
+   *
+   *  This is a total ordering relation.  It is linear in the size of the
+   *  maps.  The elements must be comparable with @c <.
+   *
+   *  See `std::lexicographical_compare_three_way()` for how the determination
+   *  is made. This operator is used to synthesize relational operators like
+   *  `<` and `>=` etc.
+  */
+  template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
+    inline __detail::__synth3way_t<pair<const _Key, _Tp>>
+    operator<=>(const multimap<_Key, _Tp, _Compare, _Alloc>& __x,
+		const multimap<_Key, _Tp, _Compare, _Alloc>& __y)
+    { return __x._M_t <=> __y._M_t; }
+#else
+  /**
+   *  @brief  Multimap ordering relation.
+   *  @param  __x  A %multimap.
+   *  @param  __y  A %multimap of the same type as @a __x.
+   *  @return  True iff @a x is lexicographically less than @a y.
+   *
+   *  This is a total ordering relation.  It is linear in the size of the
+   *  multimaps.  The elements must be comparable with @c <.
+   *
+   *  See std::lexicographical_compare() for how the determination is made.
+  */
+  template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
+    inline bool
+    operator<(const multimap<_Key, _Tp, _Compare, _Alloc>& __x,
+	      const multimap<_Key, _Tp, _Compare, _Alloc>& __y)
+    { return __x._M_t < __y._M_t; }
+
+  /// Based on operator==
+  template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
+    inline bool
+    operator!=(const multimap<_Key, _Tp, _Compare, _Alloc>& __x,
+	       const multimap<_Key, _Tp, _Compare, _Alloc>& __y)
+    { return !(__x == __y); }
+
+  /// Based on operator<
+  template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
+    inline bool
+    operator>(const multimap<_Key, _Tp, _Compare, _Alloc>& __x,
+	      const multimap<_Key, _Tp, _Compare, _Alloc>& __y)
+    { return __y < __x; }
+
+  /// Based on operator<
+  template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
+    inline bool
+    operator<=(const multimap<_Key, _Tp, _Compare, _Alloc>& __x,
+	       const multimap<_Key, _Tp, _Compare, _Alloc>& __y)
+    { return !(__y < __x); }
+
+  /// Based on operator<
+  template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
+    inline bool
+    operator>=(const multimap<_Key, _Tp, _Compare, _Alloc>& __x,
+	       const multimap<_Key, _Tp, _Compare, _Alloc>& __y)
+    { return !(__x < __y); }
+#endif // three-way comparison
+
+  /// See std::multimap::swap().
+  template<typename _Key, typename _Tp, typename _Compare, typename _Alloc>
+    inline void
+    swap(multimap<_Key, _Tp, _Compare, _Alloc>& __x,
+	 multimap<_Key, _Tp, _Compare, _Alloc>& __y)
+    _GLIBCXX_NOEXCEPT_IF(noexcept(__x.swap(__y)))
+    { __x.swap(__y); }
+
+_GLIBCXX_END_NAMESPACE_CONTAINER
+
+#if __cplusplus > 201402L
+  // Allow std::multimap access to internals of compatible maps.
+  template<typename _Key, typename _Val, typename _Cmp1, typename _Alloc,
+	   typename _Cmp2>
+    struct
+    _Rb_tree_merge_helper<_GLIBCXX_STD_C::multimap<_Key, _Val, _Cmp1, _Alloc>,
+			  _Cmp2>
+    {
+    private:
+      friend class _GLIBCXX_STD_C::multimap<_Key, _Val, _Cmp1, _Alloc>;
+
+      static auto&
+      _S_get_tree(_GLIBCXX_STD_C::map<_Key, _Val, _Cmp2, _Alloc>& __map)
+      { return __map._M_t; }
+
+      static auto&
+      _S_get_tree(_GLIBCXX_STD_C::multimap<_Key, _Val, _Cmp2, _Alloc>& __map)
+      { return __map._M_t; }
+    };
+#endif // C++17
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif /* _STL_MULTIMAP_H */
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@@ -0,0 +1,1076 @@
+// Multiset implementation -*- C++ -*-
+
+// Copyright (C) 2001-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/*
+ *
+ * Copyright (c) 1994
+ * Hewlett-Packard Company
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Hewlett-Packard Company makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ *
+ *
+ * Copyright (c) 1996
+ * Silicon Graphics Computer Systems, Inc.
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Silicon Graphics makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ */
+
+/** @file bits/stl_multiset.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{set}
+ */
+
+#ifndef _STL_MULTISET_H
+#define _STL_MULTISET_H 1
+
+#include <bits/concept_check.h>
+#if __cplusplus >= 201103L
+#include <initializer_list>
+#endif
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+_GLIBCXX_BEGIN_NAMESPACE_CONTAINER
+
+  template<typename _Key, typename _Compare, typename _Alloc>
+    class set;
+
+  /**
+   *  @brief A standard container made up of elements, which can be retrieved
+   *  in logarithmic time.
+   *
+   *  @ingroup associative_containers
+   *
+   *
+   *  @tparam _Key  Type of key objects.
+   *  @tparam _Compare  Comparison function object type, defaults to less<_Key>.
+   *  @tparam _Alloc  Allocator type, defaults to allocator<_Key>.
+   *
+   *  Meets the requirements of a <a href="tables.html#65">container</a>, a
+   *  <a href="tables.html#66">reversible container</a>, and an
+   *  <a href="tables.html#69">associative container</a> (using equivalent
+   *  keys).  For a @c multiset<Key> the key_type and value_type are Key.
+   *
+   *  Multisets support bidirectional iterators.
+   *
+   *  The private tree data is declared exactly the same way for set and
+   *  multiset; the distinction is made entirely in how the tree functions are
+   *  called (*_unique versus *_equal, same as the standard).
+  */
+  template <typename _Key, typename _Compare = std::less<_Key>,
+	    typename _Alloc = std::allocator<_Key> >
+    class multiset
+    {
+#ifdef _GLIBCXX_CONCEPT_CHECKS
+      // concept requirements
+      typedef typename _Alloc::value_type		_Alloc_value_type;
+# if __cplusplus < 201103L
+      __glibcxx_class_requires(_Key, _SGIAssignableConcept)
+# endif
+      __glibcxx_class_requires4(_Compare, bool, _Key, _Key,
+				_BinaryFunctionConcept)
+      __glibcxx_class_requires2(_Key, _Alloc_value_type, _SameTypeConcept)
+#endif
+
+#if __cplusplus >= 201103L
+      static_assert(is_same<typename remove_cv<_Key>::type, _Key>::value,
+	  "std::multiset must have a non-const, non-volatile value_type");
+# if __cplusplus > 201703L || defined __STRICT_ANSI__
+      static_assert(is_same<typename _Alloc::value_type, _Key>::value,
+	  "std::multiset must have the same value_type as its allocator");
+# endif
+#endif
+
+    public:
+      // typedefs:
+      typedef _Key     key_type;
+      typedef _Key     value_type;
+      typedef _Compare key_compare;
+      typedef _Compare value_compare;
+      typedef _Alloc   allocator_type;
+
+    private:
+      /// This turns a red-black tree into a [multi]set.
+      typedef typename __gnu_cxx::__alloc_traits<_Alloc>::template
+	rebind<_Key>::other _Key_alloc_type;
+
+      typedef _Rb_tree<key_type, value_type, _Identity<value_type>,
+		       key_compare, _Key_alloc_type> _Rep_type;
+      /// The actual tree structure.
+      _Rep_type _M_t;
+
+      typedef __gnu_cxx::__alloc_traits<_Key_alloc_type> _Alloc_traits;
+
+    public:
+      typedef typename _Alloc_traits::pointer		 pointer;
+      typedef typename _Alloc_traits::const_pointer	 const_pointer;
+      typedef typename _Alloc_traits::reference		 reference;
+      typedef typename _Alloc_traits::const_reference	 const_reference;
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // DR 103. set::iterator is required to be modifiable,
+      // but this allows modification of keys.
+      typedef typename _Rep_type::const_iterator	 iterator;
+      typedef typename _Rep_type::const_iterator	 const_iterator;
+      typedef typename _Rep_type::const_reverse_iterator reverse_iterator;
+      typedef typename _Rep_type::const_reverse_iterator const_reverse_iterator;
+      typedef typename _Rep_type::size_type		 size_type;
+      typedef typename _Rep_type::difference_type	 difference_type;
+
+#if __cplusplus > 201402L
+      using node_type = typename _Rep_type::node_type;
+#endif
+
+      // allocation/deallocation
+      /**
+       *  @brief  Default constructor creates no elements.
+       */
+#if __cplusplus < 201103L
+      multiset() : _M_t() { }
+#else
+      multiset() = default;
+#endif
+
+      /**
+       *  @brief  Creates a %multiset with no elements.
+       *  @param  __comp  Comparator to use.
+       *  @param  __a  An allocator object.
+       */
+      explicit
+      multiset(const _Compare& __comp,
+	       const allocator_type& __a = allocator_type())
+      : _M_t(__comp, _Key_alloc_type(__a)) { }
+
+      /**
+       *  @brief  Builds a %multiset from a range.
+       *  @param  __first  An input iterator.
+       *  @param  __last  An input iterator.
+       *
+       *  Create a %multiset consisting of copies of the elements from
+       *  [first,last).  This is linear in N if the range is already sorted,
+       *  and NlogN otherwise (where N is distance(__first,__last)).
+       */
+      template<typename _InputIterator>
+	multiset(_InputIterator __first, _InputIterator __last)
+	: _M_t()
+	{ _M_t._M_insert_range_equal(__first, __last); }
+
+      /**
+       *  @brief  Builds a %multiset from a range.
+       *  @param  __first  An input iterator.
+       *  @param  __last  An input iterator.
+       *  @param  __comp  A comparison functor.
+       *  @param  __a  An allocator object.
+       *
+       *  Create a %multiset consisting of copies of the elements from
+       *  [__first,__last).  This is linear in N if the range is already sorted,
+       *  and NlogN otherwise (where N is distance(__first,__last)).
+       */
+      template<typename _InputIterator>
+	multiset(_InputIterator __first, _InputIterator __last,
+		 const _Compare& __comp,
+		 const allocator_type& __a = allocator_type())
+	: _M_t(__comp, _Key_alloc_type(__a))
+	{ _M_t._M_insert_range_equal(__first, __last); }
+
+      /**
+       *  @brief  %Multiset copy constructor.
+       *
+       *  Whether the allocator is copied depends on the allocator traits.
+       */
+#if __cplusplus < 201103L
+      multiset(const multiset& __x)
+      : _M_t(__x._M_t) { }
+#else
+      multiset(const multiset&) = default;
+
+     /**
+       *  @brief  %Multiset move constructor.
+       *
+       *  The newly-created %multiset contains the exact contents of the
+       *  moved instance. The moved instance is a valid, but unspecified
+       *  %multiset.
+       */
+      multiset(multiset&&) = default;
+
+      /**
+       *  @brief  Builds a %multiset from an initializer_list.
+       *  @param  __l  An initializer_list.
+       *  @param  __comp  A comparison functor.
+       *  @param  __a  An allocator object.
+       *
+       *  Create a %multiset consisting of copies of the elements from
+       *  the list.  This is linear in N if the list is already sorted,
+       *  and NlogN otherwise (where N is @a __l.size()).
+       */
+      multiset(initializer_list<value_type> __l,
+	       const _Compare& __comp = _Compare(),
+	       const allocator_type& __a = allocator_type())
+      : _M_t(__comp, _Key_alloc_type(__a))
+      { _M_t._M_insert_range_equal(__l.begin(), __l.end()); }
+
+      /// Allocator-extended default constructor.
+      explicit
+      multiset(const allocator_type& __a)
+      : _M_t(_Key_alloc_type(__a)) { }
+
+      /// Allocator-extended copy constructor.
+      multiset(const multiset& __m,
+	       const __type_identity_t<allocator_type>& __a)
+      : _M_t(__m._M_t, _Key_alloc_type(__a)) { }
+
+      /// Allocator-extended move constructor.
+      multiset(multiset&& __m, const __type_identity_t<allocator_type>& __a)
+      noexcept(is_nothrow_copy_constructible<_Compare>::value
+	       && _Alloc_traits::_S_always_equal())
+      : _M_t(std::move(__m._M_t), _Key_alloc_type(__a)) { }
+
+      /// Allocator-extended initialier-list constructor.
+      multiset(initializer_list<value_type> __l, const allocator_type& __a)
+      : _M_t(_Key_alloc_type(__a))
+      { _M_t._M_insert_range_equal(__l.begin(), __l.end()); }
+
+      /// Allocator-extended range constructor.
+      template<typename _InputIterator>
+	multiset(_InputIterator __first, _InputIterator __last,
+		 const allocator_type& __a)
+	: _M_t(_Key_alloc_type(__a))
+	{ _M_t._M_insert_range_equal(__first, __last); }
+
+      /**
+       *  The dtor only erases the elements, and note that if the elements
+       *  themselves are pointers, the pointed-to memory is not touched in any
+       *  way. Managing the pointer is the user's responsibility.
+       */
+      ~multiset() = default;
+#endif
+
+      /**
+       *  @brief  %Multiset assignment operator.
+       *
+       *  Whether the allocator is copied depends on the allocator traits.
+       */
+#if __cplusplus < 201103L
+      multiset&
+      operator=(const multiset& __x)
+      {
+	_M_t = __x._M_t;
+	return *this;
+      }
+#else
+      multiset&
+      operator=(const multiset&) = default;
+
+      /// Move assignment operator.
+      multiset&
+      operator=(multiset&&) = default;
+
+      /**
+       *  @brief  %Multiset list assignment operator.
+       *  @param  __l  An initializer_list.
+       *
+       *  This function fills a %multiset with copies of the elements in the
+       *  initializer list @a __l.
+       *
+       *  Note that the assignment completely changes the %multiset and
+       *  that the resulting %multiset's size is the same as the number
+       *  of elements assigned.
+       */
+      multiset&
+      operator=(initializer_list<value_type> __l)
+      {
+	_M_t._M_assign_equal(__l.begin(), __l.end());
+	return *this;
+      }
+#endif
+
+      // accessors:
+
+      ///  Returns the comparison object.
+      key_compare
+      key_comp() const
+      { return _M_t.key_comp(); }
+      ///  Returns the comparison object.
+      value_compare
+      value_comp() const
+      { return _M_t.key_comp(); }
+      ///  Returns the memory allocation object.
+      allocator_type
+      get_allocator() const _GLIBCXX_NOEXCEPT
+      { return allocator_type(_M_t.get_allocator()); }
+
+      /**
+       *  Returns a read-only (constant) iterator that points to the first
+       *  element in the %multiset.  Iteration is done in ascending order
+       *  according to the keys.
+       */
+      iterator
+      begin() const _GLIBCXX_NOEXCEPT
+      { return _M_t.begin(); }
+
+      /**
+       *  Returns a read-only (constant) iterator that points one past the last
+       *  element in the %multiset.  Iteration is done in ascending order
+       *  according to the keys.
+       */
+      iterator
+      end() const _GLIBCXX_NOEXCEPT
+      { return _M_t.end(); }
+
+      /**
+       *  Returns a read-only (constant) reverse iterator that points to the
+       *  last element in the %multiset.  Iteration is done in descending order
+       *  according to the keys.
+       */
+      reverse_iterator
+      rbegin() const _GLIBCXX_NOEXCEPT
+      { return _M_t.rbegin(); }
+
+      /**
+       *  Returns a read-only (constant) reverse iterator that points to the
+       *  last element in the %multiset.  Iteration is done in descending order
+       *  according to the keys.
+       */
+      reverse_iterator
+      rend() const _GLIBCXX_NOEXCEPT
+      { return _M_t.rend(); }
+
+#if __cplusplus >= 201103L
+      /**
+       *  Returns a read-only (constant) iterator that points to the first
+       *  element in the %multiset.  Iteration is done in ascending order
+       *  according to the keys.
+       */
+      iterator
+      cbegin() const noexcept
+      { return _M_t.begin(); }
+
+      /**
+       *  Returns a read-only (constant) iterator that points one past the last
+       *  element in the %multiset.  Iteration is done in ascending order
+       *  according to the keys.
+       */
+      iterator
+      cend() const noexcept
+      { return _M_t.end(); }
+
+      /**
+       *  Returns a read-only (constant) reverse iterator that points to the
+       *  last element in the %multiset.  Iteration is done in descending order
+       *  according to the keys.
+       */
+      reverse_iterator
+      crbegin() const noexcept
+      { return _M_t.rbegin(); }
+
+      /**
+       *  Returns a read-only (constant) reverse iterator that points to the
+       *  last element in the %multiset.  Iteration is done in descending order
+       *  according to the keys.
+       */
+      reverse_iterator
+      crend() const noexcept
+      { return _M_t.rend(); }
+#endif
+
+      ///  Returns true if the %set is empty.
+      _GLIBCXX_NODISCARD bool
+      empty() const _GLIBCXX_NOEXCEPT
+      { return _M_t.empty(); }
+
+      ///  Returns the size of the %set.
+      size_type
+      size() const _GLIBCXX_NOEXCEPT
+      { return _M_t.size(); }
+
+      ///  Returns the maximum size of the %set.
+      size_type
+      max_size() const _GLIBCXX_NOEXCEPT
+      { return _M_t.max_size(); }
+
+      /**
+       *  @brief  Swaps data with another %multiset.
+       *  @param  __x  A %multiset of the same element and allocator types.
+       *
+       *  This exchanges the elements between two multisets in constant time.
+       *  (It is only swapping a pointer, an integer, and an instance of the @c
+       *  Compare type (which itself is often stateless and empty), so it should
+       *  be quite fast.)
+       *  Note that the global std::swap() function is specialized such that
+       *  std::swap(s1,s2) will feed to this function.
+       *
+       *  Whether the allocators are swapped depends on the allocator traits.
+       */
+      void
+      swap(multiset& __x)
+      _GLIBCXX_NOEXCEPT_IF(__is_nothrow_swappable<_Compare>::value)
+      { _M_t.swap(__x._M_t); }
+
+      // insert/erase
+#if __cplusplus >= 201103L
+      /**
+       *  @brief Builds and inserts an element into the %multiset.
+       *  @param  __args  Arguments used to generate the element instance to be
+       *                 inserted.
+       *  @return An iterator that points to the inserted element.
+       *
+       *  This function inserts an element into the %multiset.  Contrary
+       *  to a std::set the %multiset does not rely on unique keys and thus
+       *  multiple copies of the same element can be inserted.
+       *
+       *  Insertion requires logarithmic time.
+       */
+      template<typename... _Args>
+	iterator
+	emplace(_Args&&... __args)
+	{ return _M_t._M_emplace_equal(std::forward<_Args>(__args)...); }
+
+      /**
+       *  @brief Builds and inserts an element into the %multiset.
+       *  @param  __pos  An iterator that serves as a hint as to where the
+       *                element should be inserted.
+       *  @param  __args  Arguments used to generate the element instance to be
+       *                 inserted.
+       *  @return An iterator that points to the inserted element.
+       *
+       *  This function inserts an element into the %multiset.  Contrary
+       *  to a std::set the %multiset does not rely on unique keys and thus
+       *  multiple copies of the same element can be inserted.
+       *
+       *  Note that the first parameter is only a hint and can potentially
+       *  improve the performance of the insertion process.  A bad hint would
+       *  cause no gains in efficiency.
+       *
+       *  See https://gcc.gnu.org/onlinedocs/libstdc++/manual/associative.html#containers.associative.insert_hints
+       *  for more on @a hinting.
+       *
+       *  Insertion requires logarithmic time (if the hint is not taken).
+       */
+      template<typename... _Args>
+	iterator
+	emplace_hint(const_iterator __pos, _Args&&... __args)
+	{
+	  return _M_t._M_emplace_hint_equal(__pos,
+					    std::forward<_Args>(__args)...);
+	}
+#endif
+
+      /**
+       *  @brief Inserts an element into the %multiset.
+       *  @param  __x  Element to be inserted.
+       *  @return An iterator that points to the inserted element.
+       *
+       *  This function inserts an element into the %multiset.  Contrary
+       *  to a std::set the %multiset does not rely on unique keys and thus
+       *  multiple copies of the same element can be inserted.
+       *
+       *  Insertion requires logarithmic time.
+       */
+      iterator
+      insert(const value_type& __x)
+      { return _M_t._M_insert_equal(__x); }
+
+#if __cplusplus >= 201103L
+      iterator
+      insert(value_type&& __x)
+      { return _M_t._M_insert_equal(std::move(__x)); }
+#endif
+
+      /**
+       *  @brief Inserts an element into the %multiset.
+       *  @param  __position  An iterator that serves as a hint as to where the
+       *                    element should be inserted.
+       *  @param  __x  Element to be inserted.
+       *  @return An iterator that points to the inserted element.
+       *
+       *  This function inserts an element into the %multiset.  Contrary
+       *  to a std::set the %multiset does not rely on unique keys and thus
+       *  multiple copies of the same element can be inserted.
+       *
+       *  Note that the first parameter is only a hint and can potentially
+       *  improve the performance of the insertion process.  A bad hint would
+       *  cause no gains in efficiency.
+       *
+       *  See https://gcc.gnu.org/onlinedocs/libstdc++/manual/associative.html#containers.associative.insert_hints
+       *  for more on @a hinting.
+       *
+       *  Insertion requires logarithmic time (if the hint is not taken).
+       */
+      iterator
+      insert(const_iterator __position, const value_type& __x)
+      { return _M_t._M_insert_equal_(__position, __x); }
+
+#if __cplusplus >= 201103L
+      iterator
+      insert(const_iterator __position, value_type&& __x)
+      { return _M_t._M_insert_equal_(__position, std::move(__x)); }
+#endif
+
+      /**
+       *  @brief A template function that tries to insert a range of elements.
+       *  @param  __first  Iterator pointing to the start of the range to be
+       *                   inserted.
+       *  @param  __last  Iterator pointing to the end of the range.
+       *
+       *  Complexity similar to that of the range constructor.
+       */
+      template<typename _InputIterator>
+	void
+	insert(_InputIterator __first, _InputIterator __last)
+	{ _M_t._M_insert_range_equal(__first, __last); }
+
+#if __cplusplus >= 201103L
+      /**
+       *  @brief Attempts to insert a list of elements into the %multiset.
+       *  @param  __l  A std::initializer_list<value_type> of elements
+       *               to be inserted.
+       *
+       *  Complexity similar to that of the range constructor.
+       */
+      void
+      insert(initializer_list<value_type> __l)
+      { this->insert(__l.begin(), __l.end()); }
+#endif
+
+#if __cplusplus > 201402L
+      /// Extract a node.
+      node_type
+      extract(const_iterator __pos)
+      {
+	__glibcxx_assert(__pos != end());
+	return _M_t.extract(__pos);
+      }
+
+      /// Extract a node.
+      node_type
+      extract(const key_type& __x)
+      { return _M_t.extract(__x); }
+
+      /// Re-insert an extracted node.
+      iterator
+      insert(node_type&& __nh)
+      { return _M_t._M_reinsert_node_equal(std::move(__nh)); }
+
+      /// Re-insert an extracted node.
+      iterator
+      insert(const_iterator __hint, node_type&& __nh)
+      { return _M_t._M_reinsert_node_hint_equal(__hint, std::move(__nh)); }
+
+      template<typename, typename>
+	friend struct std::_Rb_tree_merge_helper;
+
+      template<typename _Compare1>
+	void
+	merge(multiset<_Key, _Compare1, _Alloc>& __source)
+	{
+	  using _Merge_helper = _Rb_tree_merge_helper<multiset, _Compare1>;
+	  _M_t._M_merge_equal(_Merge_helper::_S_get_tree(__source));
+	}
+
+      template<typename _Compare1>
+	void
+	merge(multiset<_Key, _Compare1, _Alloc>&& __source)
+	{ merge(__source); }
+
+      template<typename _Compare1>
+	void
+	merge(set<_Key, _Compare1, _Alloc>& __source)
+	{
+	  using _Merge_helper = _Rb_tree_merge_helper<multiset, _Compare1>;
+	  _M_t._M_merge_equal(_Merge_helper::_S_get_tree(__source));
+	}
+
+      template<typename _Compare1>
+	void
+	merge(set<_Key, _Compare1, _Alloc>&& __source)
+	{ merge(__source); }
+#endif // C++17
+
+#if __cplusplus >= 201103L
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // DR 130. Associative erase should return an iterator.
+      /**
+       *  @brief Erases an element from a %multiset.
+       *  @param  __position  An iterator pointing to the element to be erased.
+       *  @return An iterator pointing to the element immediately following
+       *          @a position prior to the element being erased. If no such
+       *          element exists, end() is returned.
+       *
+       *  This function erases an element, pointed to by the given iterator,
+       *  from a %multiset.  Note that this function only erases the element,
+       *  and that if the element is itself a pointer, the pointed-to memory is
+       *  not touched in any way.  Managing the pointer is the user's
+       *  responsibility.
+       */
+      _GLIBCXX_ABI_TAG_CXX11
+      iterator
+      erase(const_iterator __position)
+      { return _M_t.erase(__position); }
+#else
+      /**
+       *  @brief Erases an element from a %multiset.
+       *  @param  __position  An iterator pointing to the element to be erased.
+       *
+       *  This function erases an element, pointed to by the given iterator,
+       *  from a %multiset.  Note that this function only erases the element,
+       *  and that if the element is itself a pointer, the pointed-to memory is
+       *  not touched in any way.  Managing the pointer is the user's
+       *  responsibility.
+       */
+      void
+      erase(iterator __position)
+      { _M_t.erase(__position); }
+#endif
+
+      /**
+       *  @brief Erases elements according to the provided key.
+       *  @param  __x  Key of element to be erased.
+       *  @return  The number of elements erased.
+       *
+       *  This function erases all elements located by the given key from a
+       *  %multiset.
+       *  Note that this function only erases the element, and that if
+       *  the element is itself a pointer, the pointed-to memory is not touched
+       *  in any way.  Managing the pointer is the user's responsibility.
+       */
+      size_type
+      erase(const key_type& __x)
+      { return _M_t.erase(__x); }
+
+#if __cplusplus >= 201103L
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // DR 130. Associative erase should return an iterator.
+      /**
+       *  @brief Erases a [first,last) range of elements from a %multiset.
+       *  @param  __first  Iterator pointing to the start of the range to be
+       *                   erased.
+       *  @param __last Iterator pointing to the end of the range to
+       *                be erased.
+       *  @return The iterator @a last.
+       *
+       *  This function erases a sequence of elements from a %multiset.
+       *  Note that this function only erases the elements, and that if
+       *  the elements themselves are pointers, the pointed-to memory is not
+       *  touched in any way.  Managing the pointer is the user's
+       *  responsibility.
+       */
+      _GLIBCXX_ABI_TAG_CXX11
+      iterator
+      erase(const_iterator __first, const_iterator __last)
+      { return _M_t.erase(__first, __last); }
+#else
+      /**
+       *  @brief Erases a [first,last) range of elements from a %multiset.
+       *  @param  first  Iterator pointing to the start of the range to be
+       *                 erased.
+       *  @param  last  Iterator pointing to the end of the range to be erased.
+       *
+       *  This function erases a sequence of elements from a %multiset.
+       *  Note that this function only erases the elements, and that if
+       *  the elements themselves are pointers, the pointed-to memory is not
+       *  touched in any way.  Managing the pointer is the user's
+       *  responsibility.
+       */
+      void
+      erase(iterator __first, iterator __last)
+      { _M_t.erase(__first, __last); }
+#endif
+
+      /**
+       *  Erases all elements in a %multiset.  Note that this function only
+       *  erases the elements, and that if the elements themselves are pointers,
+       *  the pointed-to memory is not touched in any way.  Managing the pointer
+       *  is the user's responsibility.
+       */
+      void
+      clear() _GLIBCXX_NOEXCEPT
+      { _M_t.clear(); }
+
+      // multiset operations:
+
+      ///@{
+      /**
+       *  @brief Finds the number of elements with given key.
+       *  @param  __x  Key of elements to be located.
+       *  @return Number of elements with specified key.
+       */
+      size_type
+      count(const key_type& __x) const
+      { return _M_t.count(__x); }
+
+#if __cplusplus > 201103L
+      template<typename _Kt>
+	auto
+	count(const _Kt& __x) const -> decltype(_M_t._M_count_tr(__x))
+	{ return _M_t._M_count_tr(__x); }
+#endif
+      ///@}
+
+#if __cplusplus > 201703L
+      ///@{
+      /**
+       *  @brief  Finds whether an element with the given key exists.
+       *  @param  __x  Key of elements to be located.
+       *  @return  True if there is any element with the specified key.
+       */
+      bool
+      contains(const key_type& __x) const
+      { return _M_t.find(__x) != _M_t.end(); }
+
+      template<typename _Kt>
+	auto
+	contains(const _Kt& __x) const
+	-> decltype(_M_t._M_find_tr(__x), void(), true)
+	{ return _M_t._M_find_tr(__x) != _M_t.end(); }
+      ///@}
+#endif
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 214.  set::find() missing const overload
+      ///@{
+      /**
+       *  @brief Tries to locate an element in a %set.
+       *  @param  __x  Element to be located.
+       *  @return  Iterator pointing to sought-after element, or end() if not
+       *           found.
+       *
+       *  This function takes a key and tries to locate the element with which
+       *  the key matches.  If successful the function returns an iterator
+       *  pointing to the sought after element.  If unsuccessful it returns the
+       *  past-the-end ( @c end() ) iterator.
+       */
+      iterator
+      find(const key_type& __x)
+      { return _M_t.find(__x); }
+
+      const_iterator
+      find(const key_type& __x) const
+      { return _M_t.find(__x); }
+
+#if __cplusplus > 201103L
+      template<typename _Kt>
+	auto
+	find(const _Kt& __x)
+	-> decltype(iterator{_M_t._M_find_tr(__x)})
+	{ return iterator{_M_t._M_find_tr(__x)}; }
+
+      template<typename _Kt>
+	auto
+	find(const _Kt& __x) const
+	-> decltype(const_iterator{_M_t._M_find_tr(__x)})
+	{ return const_iterator{_M_t._M_find_tr(__x)}; }
+#endif
+      ///@}
+
+      ///@{
+      /**
+       *  @brief Finds the beginning of a subsequence matching given key.
+       *  @param  __x  Key to be located.
+       *  @return  Iterator pointing to first element equal to or greater
+       *           than key, or end().
+       *
+       *  This function returns the first element of a subsequence of elements
+       *  that matches the given key.  If unsuccessful it returns an iterator
+       *  pointing to the first element that has a greater value than given key
+       *  or end() if no such element exists.
+       */
+      iterator
+      lower_bound(const key_type& __x)
+      { return _M_t.lower_bound(__x); }
+
+      const_iterator
+      lower_bound(const key_type& __x) const
+      { return _M_t.lower_bound(__x); }
+
+#if __cplusplus > 201103L
+      template<typename _Kt>
+	auto
+	lower_bound(const _Kt& __x)
+	-> decltype(iterator(_M_t._M_lower_bound_tr(__x)))
+	{ return iterator(_M_t._M_lower_bound_tr(__x)); }
+
+      template<typename _Kt>
+	auto
+	lower_bound(const _Kt& __x) const
+	-> decltype(iterator(_M_t._M_lower_bound_tr(__x)))
+	{ return iterator(_M_t._M_lower_bound_tr(__x)); }
+#endif
+      ///@}
+
+      ///@{
+      /**
+       *  @brief Finds the end of a subsequence matching given key.
+       *  @param  __x  Key to be located.
+       *  @return Iterator pointing to the first element
+       *          greater than key, or end().
+       */
+      iterator
+      upper_bound(const key_type& __x)
+      { return _M_t.upper_bound(__x); }
+
+      const_iterator
+      upper_bound(const key_type& __x) const
+      { return _M_t.upper_bound(__x); }
+
+#if __cplusplus > 201103L
+      template<typename _Kt>
+	auto
+	upper_bound(const _Kt& __x)
+	-> decltype(iterator(_M_t._M_upper_bound_tr(__x)))
+	{ return iterator(_M_t._M_upper_bound_tr(__x)); }
+
+      template<typename _Kt>
+	auto
+	upper_bound(const _Kt& __x) const
+	-> decltype(iterator(_M_t._M_upper_bound_tr(__x)))
+	{ return iterator(_M_t._M_upper_bound_tr(__x)); }
+#endif
+      ///@}
+
+      ///@{
+      /**
+       *  @brief Finds a subsequence matching given key.
+       *  @param  __x  Key to be located.
+       *  @return  Pair of iterators that possibly points to the subsequence
+       *           matching given key.
+       *
+       *  This function is equivalent to
+       *  @code
+       *    std::make_pair(c.lower_bound(val),
+       *                   c.upper_bound(val))
+       *  @endcode
+       *  (but is faster than making the calls separately).
+       *
+       *  This function probably only makes sense for multisets.
+       */
+      std::pair<iterator, iterator>
+      equal_range(const key_type& __x)
+      { return _M_t.equal_range(__x); }
+
+      std::pair<const_iterator, const_iterator>
+      equal_range(const key_type& __x) const
+      { return _M_t.equal_range(__x); }
+
+#if __cplusplus > 201103L
+      template<typename _Kt>
+	auto
+	equal_range(const _Kt& __x)
+	-> decltype(pair<iterator, iterator>(_M_t._M_equal_range_tr(__x)))
+	{ return pair<iterator, iterator>(_M_t._M_equal_range_tr(__x)); }
+
+      template<typename _Kt>
+	auto
+	equal_range(const _Kt& __x) const
+	-> decltype(pair<iterator, iterator>(_M_t._M_equal_range_tr(__x)))
+	{ return pair<iterator, iterator>(_M_t._M_equal_range_tr(__x)); }
+#endif
+      ///@}
+
+      template<typename _K1, typename _C1, typename _A1>
+	friend bool
+	operator==(const multiset<_K1, _C1, _A1>&,
+		   const multiset<_K1, _C1, _A1>&);
+
+#if __cpp_lib_three_way_comparison
+      template<typename _K1, typename _C1, typename _A1>
+	friend __detail::__synth3way_t<_K1>
+	operator<=>(const multiset<_K1, _C1, _A1>&,
+		    const multiset<_K1, _C1, _A1>&);
+#else
+      template<typename _K1, typename _C1, typename _A1>
+	friend bool
+	operator< (const multiset<_K1, _C1, _A1>&,
+		   const multiset<_K1, _C1, _A1>&);
+#endif
+    };
+
+#if __cpp_deduction_guides >= 201606
+
+  template<typename _InputIterator,
+	   typename _Compare =
+	     less<typename iterator_traits<_InputIterator>::value_type>,
+	   typename _Allocator =
+	     allocator<typename iterator_traits<_InputIterator>::value_type>,
+	   typename = _RequireInputIter<_InputIterator>,
+	   typename = _RequireNotAllocator<_Compare>,
+	   typename = _RequireAllocator<_Allocator>>
+    multiset(_InputIterator, _InputIterator,
+	     _Compare = _Compare(), _Allocator = _Allocator())
+    -> multiset<typename iterator_traits<_InputIterator>::value_type,
+		_Compare, _Allocator>;
+
+  template<typename _Key,
+	   typename _Compare = less<_Key>,
+	   typename _Allocator = allocator<_Key>,
+	   typename = _RequireNotAllocator<_Compare>,
+	   typename = _RequireAllocator<_Allocator>>
+    multiset(initializer_list<_Key>,
+	     _Compare = _Compare(), _Allocator = _Allocator())
+    -> multiset<_Key, _Compare, _Allocator>;
+
+  template<typename _InputIterator, typename _Allocator,
+	   typename = _RequireInputIter<_InputIterator>,
+	   typename = _RequireAllocator<_Allocator>>
+    multiset(_InputIterator, _InputIterator, _Allocator)
+    -> multiset<typename iterator_traits<_InputIterator>::value_type,
+	        less<typename iterator_traits<_InputIterator>::value_type>,
+	        _Allocator>;
+
+  template<typename _Key, typename _Allocator,
+	   typename = _RequireAllocator<_Allocator>>
+    multiset(initializer_list<_Key>, _Allocator)
+    -> multiset<_Key, less<_Key>, _Allocator>;
+
+#endif // deduction guides
+
+  /**
+   *  @brief  Multiset equality comparison.
+   *  @param  __x  A %multiset.
+   *  @param  __y  A %multiset of the same type as @a __x.
+   *  @return  True iff the size and elements of the multisets are equal.
+   *
+   *  This is an equivalence relation.  It is linear in the size of the
+   *  multisets.
+   *  Multisets are considered equivalent if their sizes are equal, and if
+   *  corresponding elements compare equal.
+  */
+  template<typename _Key, typename _Compare, typename _Alloc>
+    inline bool
+    operator==(const multiset<_Key, _Compare, _Alloc>& __x,
+	       const multiset<_Key, _Compare, _Alloc>& __y)
+    { return __x._M_t == __y._M_t; }
+
+#if __cpp_lib_three_way_comparison
+  /**
+   *  @brief  Multiset ordering relation.
+   *  @param  __x  A `multiset`.
+   *  @param  __y  A `multiset` of the same type as `x`.
+   *  @return  A value indicating whether `__x` is less than, equal to,
+   *           greater than, or incomparable with `__y`.
+   *
+   *  This is a total ordering relation.  It is linear in the size of the
+   *  maps.  The elements must be comparable with @c <.
+   *
+   *  See `std::lexicographical_compare_three_way()` for how the determination
+   *  is made. This operator is used to synthesize relational operators like
+   *  `<` and `>=` etc.
+  */
+  template<typename _Key, typename _Compare, typename _Alloc>
+    inline __detail::__synth3way_t<_Key>
+    operator<=>(const multiset<_Key, _Compare, _Alloc>& __x,
+		const multiset<_Key, _Compare, _Alloc>& __y)
+    { return __x._M_t <=> __y._M_t; }
+#else
+  /**
+   *  @brief  Multiset ordering relation.
+   *  @param  __x  A %multiset.
+   *  @param  __y  A %multiset of the same type as @a __x.
+   *  @return  True iff @a __x is lexicographically less than @a __y.
+   *
+   *  This is a total ordering relation.  It is linear in the size of the
+   *  sets.  The elements must be comparable with @c <.
+   *
+   *  See std::lexicographical_compare() for how the determination is made.
+  */
+  template<typename _Key, typename _Compare, typename _Alloc>
+    inline bool
+    operator<(const multiset<_Key, _Compare, _Alloc>& __x,
+	      const multiset<_Key, _Compare, _Alloc>& __y)
+    { return __x._M_t < __y._M_t; }
+
+  ///  Returns !(x == y).
+  template<typename _Key, typename _Compare, typename _Alloc>
+    inline bool
+    operator!=(const multiset<_Key, _Compare, _Alloc>& __x,
+	       const multiset<_Key, _Compare, _Alloc>& __y)
+    { return !(__x == __y); }
+
+  ///  Returns y < x.
+  template<typename _Key, typename _Compare, typename _Alloc>
+    inline bool
+    operator>(const multiset<_Key,_Compare,_Alloc>& __x,
+	      const multiset<_Key,_Compare,_Alloc>& __y)
+    { return __y < __x; }
+
+  ///  Returns !(y < x)
+  template<typename _Key, typename _Compare, typename _Alloc>
+    inline bool
+    operator<=(const multiset<_Key, _Compare, _Alloc>& __x,
+	       const multiset<_Key, _Compare, _Alloc>& __y)
+    { return !(__y < __x); }
+
+  ///  Returns !(x < y)
+  template<typename _Key, typename _Compare, typename _Alloc>
+    inline bool
+    operator>=(const multiset<_Key, _Compare, _Alloc>& __x,
+	       const multiset<_Key, _Compare, _Alloc>& __y)
+    { return !(__x < __y); }
+#endif // three-way comparison
+
+  /// See std::multiset::swap().
+  template<typename _Key, typename _Compare, typename _Alloc>
+    inline void
+    swap(multiset<_Key, _Compare, _Alloc>& __x,
+	 multiset<_Key, _Compare, _Alloc>& __y)
+    _GLIBCXX_NOEXCEPT_IF(noexcept(__x.swap(__y)))
+    { __x.swap(__y); }
+
+_GLIBCXX_END_NAMESPACE_CONTAINER
+
+#if __cplusplus > 201402L
+  // Allow std::multiset access to internals of compatible sets.
+  template<typename _Val, typename _Cmp1, typename _Alloc, typename _Cmp2>
+    struct
+    _Rb_tree_merge_helper<_GLIBCXX_STD_C::multiset<_Val, _Cmp1, _Alloc>,
+			  _Cmp2>
+    {
+    private:
+      friend class _GLIBCXX_STD_C::multiset<_Val, _Cmp1, _Alloc>;
+
+      static auto&
+      _S_get_tree(_GLIBCXX_STD_C::set<_Val, _Cmp2, _Alloc>& __set)
+      { return __set._M_t; }
+
+      static auto&
+      _S_get_tree(_GLIBCXX_STD_C::multiset<_Val, _Cmp2, _Alloc>& __set)
+      { return __set._M_t; }
+    };
+#endif // C++17
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif /* _STL_MULTISET_H */
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stl_numeric.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stl_numeric.h
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stl_numeric.h
@@ -0,0 +1,413 @@
+// Numeric functions implementation -*- C++ -*-
+
+// Copyright (C) 2001-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/*
+ *
+ * Copyright (c) 1994
+ * Hewlett-Packard Company
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Hewlett-Packard Company makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ *
+ *
+ * Copyright (c) 1996,1997
+ * Silicon Graphics Computer Systems, Inc.
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Silicon Graphics makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ */
+
+/** @file bits/stl_numeric.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{numeric}
+ */
+
+#ifndef _STL_NUMERIC_H
+#define _STL_NUMERIC_H 1
+
+#include <bits/concept_check.h>
+#include <debug/debug.h>
+#include <bits/move.h> // For _GLIBCXX_MOVE
+
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /** @defgroup numeric_ops Generalized Numeric operations
+   *  @ingroup algorithms
+   */
+
+#if __cplusplus >= 201103L
+  /**
+   *  @brief  Create a range of sequentially increasing values.
+   *
+   *  For each element in the range @p [first,last) assigns @p value and
+   *  increments @p value as if by @p ++value.
+   *
+   *  @param  __first  Start of range.
+   *  @param  __last  End of range.
+   *  @param  __value  Starting value.
+   *  @return  Nothing.
+   *  @ingroup numeric_ops
+   */
+  template<typename _ForwardIterator, typename _Tp>
+    _GLIBCXX20_CONSTEXPR
+    void
+    iota(_ForwardIterator __first, _ForwardIterator __last, _Tp __value)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
+				  _ForwardIterator>)
+      __glibcxx_function_requires(_ConvertibleConcept<_Tp,
+	    typename iterator_traits<_ForwardIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      for (; __first != __last; ++__first)
+	{
+	  *__first = __value;
+	  ++__value;
+	}
+    }
+#endif
+
+_GLIBCXX_END_NAMESPACE_VERSION
+
+_GLIBCXX_BEGIN_NAMESPACE_ALGO
+
+#if __cplusplus > 201703L
+// _GLIBCXX_RESOLVE_LIB_DEFECTS
+// DR 2055. std::move in std::accumulate and other algorithms
+# define _GLIBCXX_MOVE_IF_20(_E) std::move(_E)
+#else
+# define _GLIBCXX_MOVE_IF_20(_E) _E
+#endif
+
+  /// @addtogroup numeric_ops
+  /// @{
+
+  /**
+   *  @brief  Accumulate values in a range.
+   *
+   *  Accumulates the values in the range [first,last) using operator+().  The
+   *  initial value is @a init.  The values are processed in order.
+   *
+   *  @param  __first  Start of range.
+   *  @param  __last  End of range.
+   *  @param  __init  Starting value to add other values to.
+   *  @return  The final sum.
+   */
+  template<typename _InputIterator, typename _Tp>
+    _GLIBCXX20_CONSTEXPR
+    inline _Tp
+    accumulate(_InputIterator __first, _InputIterator __last, _Tp __init)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      for (; __first != __last; ++__first)
+	__init = _GLIBCXX_MOVE_IF_20(__init) + *__first;
+      return __init;
+    }
+
+  /**
+   *  @brief  Accumulate values in a range with operation.
+   *
+   *  Accumulates the values in the range `[first,last)` using the function
+   *  object `__binary_op`.  The initial value is `__init`.  The values are
+   *  processed in order.
+   *
+   *  @param  __first  Start of range.
+   *  @param  __last  End of range.
+   *  @param  __init  Starting value to add other values to.
+   *  @param  __binary_op  Function object to accumulate with.
+   *  @return  The final sum.
+   */
+  template<typename _InputIterator, typename _Tp, typename _BinaryOperation>
+    _GLIBCXX20_CONSTEXPR
+    inline _Tp
+    accumulate(_InputIterator __first, _InputIterator __last, _Tp __init,
+	       _BinaryOperation __binary_op)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      for (; __first != __last; ++__first)
+	__init = __binary_op(_GLIBCXX_MOVE_IF_20(__init), *__first);
+      return __init;
+    }
+
+  /**
+   *  @brief  Compute inner product of two ranges.
+   *
+   *  Starting with an initial value of @p __init, multiplies successive
+   *  elements from the two ranges and adds each product into the accumulated
+   *  value using operator+().  The values in the ranges are processed in
+   *  order.
+   *
+   *  @param  __first1  Start of range 1.
+   *  @param  __last1  End of range 1.
+   *  @param  __first2  Start of range 2.
+   *  @param  __init  Starting value to add other values to.
+   *  @return  The final inner product.
+   */
+  template<typename _InputIterator1, typename _InputIterator2, typename _Tp>
+    _GLIBCXX20_CONSTEXPR
+    inline _Tp
+    inner_product(_InputIterator1 __first1, _InputIterator1 __last1,
+		  _InputIterator2 __first2, _Tp __init)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
+      __glibcxx_requires_valid_range(__first1, __last1);
+
+      for (; __first1 != __last1; ++__first1, (void)++__first2)
+	__init = _GLIBCXX_MOVE_IF_20(__init) + (*__first1 * *__first2);
+      return __init;
+    }
+
+  /**
+   *  @brief  Compute inner product of two ranges.
+   *
+   *  Starting with an initial value of @p __init, applies @p __binary_op2 to
+   *  successive elements from the two ranges and accumulates each result into
+   *  the accumulated value using @p __binary_op1.  The values in the ranges are
+   *  processed in order.
+   *
+   *  @param  __first1  Start of range 1.
+   *  @param  __last1  End of range 1.
+   *  @param  __first2  Start of range 2.
+   *  @param  __init  Starting value to add other values to.
+   *  @param  __binary_op1  Function object to accumulate with.
+   *  @param  __binary_op2  Function object to apply to pairs of input values.
+   *  @return  The final inner product.
+   */
+  template<typename _InputIterator1, typename _InputIterator2, typename _Tp,
+	   typename _BinaryOperation1, typename _BinaryOperation2>
+    _GLIBCXX20_CONSTEXPR
+    inline _Tp
+    inner_product(_InputIterator1 __first1, _InputIterator1 __last1,
+		  _InputIterator2 __first2, _Tp __init,
+		  _BinaryOperation1 __binary_op1,
+		  _BinaryOperation2 __binary_op2)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
+      __glibcxx_requires_valid_range(__first1, __last1);
+
+      for (; __first1 != __last1; ++__first1, (void)++__first2)
+	__init = __binary_op1(_GLIBCXX_MOVE_IF_20(__init),
+			      __binary_op2(*__first1, *__first2));
+      return __init;
+    }
+
+  /**
+   *  @brief  Return list of partial sums
+   *
+   *  Accumulates the values in the range [first,last) using the @c + operator.
+   *  As each successive input value is added into the total, that partial sum
+   *  is written to @p __result.  Therefore, the first value in @p __result is
+   *  the first value of the input, the second value in @p __result is the sum
+   *  of the first and second input values, and so on.
+   *
+   *  @param  __first  Start of input range.
+   *  @param  __last  End of input range.
+   *  @param  __result  Output sum.
+   *  @return  Iterator pointing just beyond the values written to __result.
+   */
+  template<typename _InputIterator, typename _OutputIterator>
+    _GLIBCXX20_CONSTEXPR
+    _OutputIterator
+    partial_sum(_InputIterator __first, _InputIterator __last,
+		_OutputIterator __result)
+    {
+      typedef typename iterator_traits<_InputIterator>::value_type _ValueType;
+
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
+				                         _ValueType>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      if (__first == __last)
+	return __result;
+      _ValueType __value = *__first;
+      *__result = __value;
+      while (++__first != __last)
+	{
+	  __value = _GLIBCXX_MOVE_IF_20(__value) + *__first;
+	  *++__result = __value;
+	}
+      return ++__result;
+    }
+
+  /**
+   *  @brief  Return list of partial sums
+   *
+   *  Accumulates the values in the range [first,last) using @p __binary_op.
+   *  As each successive input value is added into the total, that partial sum
+   *  is written to @p __result.  Therefore, the first value in @p __result is
+   *  the first value of the input, the second value in @p __result is the sum
+   *  of the first and second input values, and so on.
+   *
+   *  @param  __first  Start of input range.
+   *  @param  __last  End of input range.
+   *  @param  __result  Output sum.
+   *  @param  __binary_op  Function object.
+   *  @return  Iterator pointing just beyond the values written to __result.
+   */
+  template<typename _InputIterator, typename _OutputIterator,
+	   typename _BinaryOperation>
+    _GLIBCXX20_CONSTEXPR
+    _OutputIterator
+    partial_sum(_InputIterator __first, _InputIterator __last,
+		_OutputIterator __result, _BinaryOperation __binary_op)
+    {
+      typedef typename iterator_traits<_InputIterator>::value_type _ValueType;
+
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
+				                         _ValueType>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      if (__first == __last)
+	return __result;
+      _ValueType __value = *__first;
+      *__result = __value;
+      while (++__first != __last)
+	{
+	  __value = __binary_op(_GLIBCXX_MOVE_IF_20(__value), *__first);
+	  *++__result = __value;
+	}
+      return ++__result;
+    }
+
+  /**
+   *  @brief  Return differences between adjacent values.
+   *
+   *  Computes the difference between adjacent values in the range
+   *  [first,last) using operator-() and writes the result to @p __result.
+   *
+   *  @param  __first  Start of input range.
+   *  @param  __last  End of input range.
+   *  @param  __result  Output sums.
+   *  @return  Iterator pointing just beyond the values written to result.
+   *
+   *  _GLIBCXX_RESOLVE_LIB_DEFECTS
+   *  DR 539. partial_sum and adjacent_difference should mention requirements
+   */
+  template<typename _InputIterator, typename _OutputIterator>
+    _GLIBCXX20_CONSTEXPR
+    _OutputIterator
+    adjacent_difference(_InputIterator __first,
+			_InputIterator __last, _OutputIterator __result)
+    {
+      typedef typename iterator_traits<_InputIterator>::value_type _ValueType;
+
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
+				                         _ValueType>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      if (__first == __last)
+	return __result;
+      _ValueType __value = *__first;
+      *__result = __value;
+      while (++__first != __last)
+	{
+	  _ValueType __tmp = *__first;
+	  *++__result = __tmp - _GLIBCXX_MOVE_IF_20(__value);
+	  __value = _GLIBCXX_MOVE(__tmp);
+	}
+      return ++__result;
+    }
+
+  /**
+   *  @brief  Return differences between adjacent values.
+   *
+   *  Computes the difference between adjacent values in the range
+   *  [__first,__last) using the function object @p __binary_op and writes the
+   *  result to @p __result.
+   *
+   *  @param  __first  Start of input range.
+   *  @param  __last  End of input range.
+   *  @param  __result  Output sum.
+   *  @param  __binary_op Function object.
+   *  @return  Iterator pointing just beyond the values written to result.
+   *
+   *  _GLIBCXX_RESOLVE_LIB_DEFECTS
+   *  DR 539. partial_sum and adjacent_difference should mention requirements
+   */
+  template<typename _InputIterator, typename _OutputIterator,
+	   typename _BinaryOperation>
+    _GLIBCXX20_CONSTEXPR
+    _OutputIterator
+    adjacent_difference(_InputIterator __first, _InputIterator __last,
+			_OutputIterator __result, _BinaryOperation __binary_op)
+    {
+      typedef typename iterator_traits<_InputIterator>::value_type _ValueType;
+
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
+				                         _ValueType>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      if (__first == __last)
+	return __result;
+      _ValueType __value = *__first;
+      *__result = __value;
+      while (++__first != __last)
+	{
+	  _ValueType __tmp = *__first;
+	  *++__result = __binary_op(__tmp, _GLIBCXX_MOVE_IF_20(__value));
+	  __value = _GLIBCXX_MOVE(__tmp);
+	}
+      return ++__result;
+    }
+
+  /// @} group numeric_ops
+
+#undef _GLIBCXX_MOVE_IF_20
+
+_GLIBCXX_END_NAMESPACE_ALGO
+} // namespace std
+
+#endif /* _STL_NUMERIC_H */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stl_numeric.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stl_numeric.h.blob
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@@ -0,0 +1,924 @@
+// Pair implementation -*- C++ -*-
+
+// Copyright (C) 2001-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/*
+ *
+ * Copyright (c) 1994
+ * Hewlett-Packard Company
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Hewlett-Packard Company makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ *
+ *
+ * Copyright (c) 1996,1997
+ * Silicon Graphics Computer Systems, Inc.
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Silicon Graphics makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ */
+
+/** @file bits/stl_pair.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{utility}
+ */
+
+#ifndef _STL_PAIR_H
+#define _STL_PAIR_H 1
+
+#if __cplusplus >= 201103L
+# include <type_traits>    // for std::__decay_and_strip
+# include <bits/move.h>    // for std::move / std::forward, and std::swap
+# include <bits/utility.h> // for std::tuple_element, std::tuple_size
+#endif
+#if __cplusplus >= 202002L
+# include <compare>
+# define __cpp_lib_constexpr_utility 201811L
+#endif
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /**
+   *  @addtogroup utilities
+   *  @{
+   */
+
+#if __cplusplus >= 201103L
+  /// Tag type for piecewise construction of std::pair objects.
+  struct piecewise_construct_t { explicit piecewise_construct_t() = default; };
+
+  /// Tag for piecewise construction of std::pair objects.
+  _GLIBCXX17_INLINE constexpr piecewise_construct_t piecewise_construct =
+    piecewise_construct_t();
+
+  /// @cond undocumented
+
+  // Forward declarations.
+  template<typename...>
+    class tuple;
+
+  template<size_t...>
+    struct _Index_tuple;
+
+#if ! __cpp_lib_concepts
+  // Concept utility functions, reused in conditionally-explicit
+  // constructors.
+  // See PR 70437, don't look at is_constructible or
+  // is_convertible if the types are the same to
+  // avoid querying those properties for incomplete types.
+  template <bool, typename _T1, typename _T2>
+    struct _PCC
+    {
+      template <typename _U1, typename _U2>
+      static constexpr bool _ConstructiblePair()
+      {
+	return __and_<is_constructible<_T1, const _U1&>,
+		      is_constructible<_T2, const _U2&>>::value;
+      }
+
+      template <typename _U1, typename _U2>
+      static constexpr bool _ImplicitlyConvertiblePair()
+      {
+	return __and_<is_convertible<const _U1&, _T1>,
+		      is_convertible<const _U2&, _T2>>::value;
+      }
+
+      template <typename _U1, typename _U2>
+      static constexpr bool _MoveConstructiblePair()
+      {
+	return __and_<is_constructible<_T1, _U1&&>,
+		      is_constructible<_T2, _U2&&>>::value;
+      }
+
+      template <typename _U1, typename _U2>
+      static constexpr bool _ImplicitlyMoveConvertiblePair()
+      {
+	return __and_<is_convertible<_U1&&, _T1>,
+		      is_convertible<_U2&&, _T2>>::value;
+      }
+    };
+
+  template <typename _T1, typename _T2>
+    struct _PCC<false, _T1, _T2>
+    {
+      template <typename _U1, typename _U2>
+      static constexpr bool _ConstructiblePair()
+      {
+	return false;
+      }
+
+      template <typename _U1, typename _U2>
+      static constexpr bool _ImplicitlyConvertiblePair()
+      {
+	return false;
+      }
+
+      template <typename _U1, typename _U2>
+      static constexpr bool _MoveConstructiblePair()
+      {
+	return false;
+      }
+
+      template <typename _U1, typename _U2>
+      static constexpr bool _ImplicitlyMoveConvertiblePair()
+      {
+	return false;
+      }
+    };
+#endif // lib concepts
+#endif // C++11
+
+  template<typename _U1, typename _U2> class __pair_base
+  {
+#if __cplusplus >= 201103L && ! __cpp_lib_concepts
+    template<typename _T1, typename _T2> friend struct pair;
+    __pair_base() = default;
+    ~__pair_base() = default;
+    __pair_base(const __pair_base&) = default;
+    __pair_base& operator=(const __pair_base&) = delete;
+#endif // C++11
+  };
+
+  /// @endcond
+
+ /**
+   *  @brief Struct holding two objects of arbitrary type.
+   *
+   *  @tparam _T1  Type of first object.
+   *  @tparam _T2  Type of second object.
+   *
+   *  <https://gcc.gnu.org/onlinedocs/libstdc++/manual/utilities.html>
+   */
+  template<typename _T1, typename _T2>
+    struct pair
+    : public __pair_base<_T1, _T2>
+    {
+      typedef _T1 first_type;    ///< The type of the `first` member
+      typedef _T2 second_type;   ///< The type of the `second` member
+
+      _T1 first;                 ///< The first member
+      _T2 second;                ///< The second member
+
+#if __cplusplus >= 201103L
+      constexpr pair(const pair&) = default;	///< Copy constructor
+      constexpr pair(pair&&) = default;		///< Move constructor
+
+      template<typename... _Args1, typename... _Args2>
+	_GLIBCXX20_CONSTEXPR
+	pair(piecewise_construct_t, tuple<_Args1...>, tuple<_Args2...>);
+
+      /// Swap the first members and then the second members.
+      _GLIBCXX20_CONSTEXPR void
+      swap(pair& __p)
+      noexcept(__and_<__is_nothrow_swappable<_T1>,
+		      __is_nothrow_swappable<_T2>>::value)
+      {
+	using std::swap;
+	swap(first, __p.first);
+	swap(second, __p.second);
+      }
+
+    private:
+      template<typename... _Args1, size_t... _Indexes1,
+	       typename... _Args2, size_t... _Indexes2>
+	_GLIBCXX20_CONSTEXPR
+	pair(tuple<_Args1...>&, tuple<_Args2...>&,
+	     _Index_tuple<_Indexes1...>, _Index_tuple<_Indexes2...>);
+    public:
+
+#if __cpp_lib_concepts
+      // C++20 implementation using concepts, explicit(bool), fully constexpr.
+
+      /// Default constructor
+      constexpr
+      explicit(__not_<__and_<__is_implicitly_default_constructible<_T1>,
+			     __is_implicitly_default_constructible<_T2>>>())
+      pair()
+      requires is_default_constructible_v<_T1>
+	       && is_default_constructible_v<_T2>
+      : first(), second()
+      { }
+
+    private:
+
+      /// @cond undocumented
+      template<typename _U1, typename _U2>
+	static constexpr bool
+	_S_constructible()
+	{
+	  if constexpr (is_constructible_v<_T1, _U1>)
+	    return is_constructible_v<_T2, _U2>;
+	  return false;
+	}
+
+      template<typename _U1, typename _U2>
+	static constexpr bool
+	_S_nothrow_constructible()
+	{
+	  if constexpr (is_nothrow_constructible_v<_T1, _U1>)
+	    return is_nothrow_constructible_v<_T2, _U2>;
+	  return false;
+	}
+
+      template<typename _U1, typename _U2>
+	static constexpr bool
+	_S_convertible()
+	{
+	  if constexpr (is_convertible_v<_U1, _T1>)
+	    return is_convertible_v<_U2, _T2>;
+	  return false;
+	}
+      /// @endcond
+
+    public:
+
+      /// Constructor accepting lvalues of `first_type` and `second_type`
+      constexpr explicit(!_S_convertible<const _T1&, const _T2&>())
+      pair(const _T1& __x, const _T2& __y)
+      noexcept(_S_nothrow_constructible<const _T1&, const _T2&>())
+      requires (_S_constructible<const _T1&, const _T2&>())
+      : first(__x), second(__y)
+      { }
+
+      /// Constructor accepting two values of arbitrary types
+      template<typename _U1, typename _U2>
+	requires (_S_constructible<_U1, _U2>())
+	constexpr explicit(!_S_convertible<_U1, _U2>())
+	pair(_U1&& __x, _U2&& __y)
+	noexcept(_S_nothrow_constructible<_U1, _U2>())
+	: first(std::forward<_U1>(__x)), second(std::forward<_U2>(__y))
+	{ }
+
+      /// Converting constructor from a `pair<U1, U2>` lvalue
+      template<typename _U1, typename _U2>
+	requires (_S_constructible<const _U1&, const _U2&>())
+	constexpr explicit(!_S_convertible<const _U1&, const _U2&>())
+	pair(const pair<_U1, _U2>& __p)
+	noexcept(_S_nothrow_constructible<const _U1&, const _U2&>())
+	: first(__p.first), second(__p.second)
+	{ }
+
+      /// Converting constructor from a `pair<U1, U2>` rvalue
+      template<typename _U1, typename _U2>
+	requires (_S_constructible<_U1, _U2>())
+	constexpr explicit(!_S_convertible<_U1, _U2>())
+	pair(pair<_U1, _U2>&& __p)
+	noexcept(_S_nothrow_constructible<_U1, _U2>())
+	: first(std::forward<_U1>(__p.first)),
+	  second(std::forward<_U2>(__p.second))
+	{ }
+
+  private:
+      /// @cond undocumented
+      template<typename _U1, typename _U2>
+	static constexpr bool
+	_S_assignable()
+	{
+	  if constexpr (is_assignable_v<_T1&, _U1>)
+	    return is_assignable_v<_T2&, _U2>;
+	  return false;
+	}
+
+      template<typename _U1, typename _U2>
+	static constexpr bool
+	_S_nothrow_assignable()
+	{
+	  if constexpr (is_nothrow_assignable_v<_T1&, _U1>)
+	    return is_nothrow_assignable_v<_T2&, _U2>;
+	  return false;
+	}
+      /// @endcond
+
+  public:
+
+      pair& operator=(const pair&) = delete;
+
+      /// Copy assignment operator
+      constexpr pair&
+      operator=(const pair& __p)
+      noexcept(_S_nothrow_assignable<const _T1&, const _T2&>())
+      requires (_S_assignable<const _T1&, const _T2&>())
+      {
+	first = __p.first;
+	second = __p.second;
+	return *this;
+      }
+
+      /// Move assignment operator
+      constexpr pair&
+      operator=(pair&& __p)
+      noexcept(_S_nothrow_assignable<_T1, _T2>())
+      requires (_S_assignable<_T1, _T2>())
+      {
+	first = std::forward<first_type>(__p.first);
+	second = std::forward<second_type>(__p.second);
+	return *this;
+      }
+
+      /// Converting assignment from a `pair<U1, U2>` lvalue
+      template<typename _U1, typename _U2>
+	constexpr pair&
+	operator=(const pair<_U1, _U2>& __p)
+	noexcept(_S_nothrow_assignable<const _U1&, const _U2&>())
+	requires (_S_assignable<const _U1&, const _U2&>())
+	{
+	  first = __p.first;
+	  second = __p.second;
+	  return *this;
+	}
+
+      /// Converting assignment from a `pair<U1, U2>` rvalue
+      template<typename _U1, typename _U2>
+	constexpr pair&
+	operator=(pair<_U1, _U2>&& __p)
+	noexcept(_S_nothrow_assignable<_U1, _U2>())
+	requires (_S_assignable<_U1, _U2>())
+	{
+	  first = std::forward<_U1>(__p.first);
+	  second = std::forward<_U2>(__p.second);
+	  return *this;
+	}
+#else
+      // C++11/14/17 implementation using enable_if, partially constexpr.
+
+      /** The default constructor creates @c first and @c second using their
+       *  respective default constructors.  */
+      template <typename _U1 = _T1,
+                typename _U2 = _T2,
+                typename enable_if<__and_<
+                                     __is_implicitly_default_constructible<_U1>,
+                                     __is_implicitly_default_constructible<_U2>>
+                                   ::value, bool>::type = true>
+      constexpr pair()
+      : first(), second() { }
+
+      template <typename _U1 = _T1,
+                typename _U2 = _T2,
+                typename enable_if<__and_<
+                       is_default_constructible<_U1>,
+                       is_default_constructible<_U2>,
+                       __not_<
+                         __and_<__is_implicitly_default_constructible<_U1>,
+                                __is_implicitly_default_constructible<_U2>>>>
+                                   ::value, bool>::type = false>
+      explicit constexpr pair()
+      : first(), second() { }
+
+      // Shortcut for constraining the templates that don't take pairs.
+      /// @cond undocumented
+      using _PCCP = _PCC<true, _T1, _T2>;
+      /// @endcond
+
+      /// Construct from two const lvalues, allowing implicit conversions.
+      template<typename _U1 = _T1, typename _U2=_T2, typename
+	       enable_if<_PCCP::template
+			   _ConstructiblePair<_U1, _U2>()
+	                 && _PCCP::template
+			   _ImplicitlyConvertiblePair<_U1, _U2>(),
+                         bool>::type=true>
+      constexpr pair(const _T1& __a, const _T2& __b)
+      : first(__a), second(__b) { }
+
+      /// Construct from two const lvalues, disallowing implicit conversions.
+       template<typename _U1 = _T1, typename _U2=_T2, typename
+		enable_if<_PCCP::template
+			    _ConstructiblePair<_U1, _U2>()
+	                  && !_PCCP::template
+			    _ImplicitlyConvertiblePair<_U1, _U2>(),
+                         bool>::type=false>
+      explicit constexpr pair(const _T1& __a, const _T2& __b)
+      : first(__a), second(__b) { }
+
+      // Shortcut for constraining the templates that take pairs.
+      /// @cond undocumented
+      template <typename _U1, typename _U2>
+        using _PCCFP = _PCC<!is_same<_T1, _U1>::value
+			    || !is_same<_T2, _U2>::value,
+			    _T1, _T2>;
+      /// @endcond
+
+      template<typename _U1, typename _U2, typename
+	       enable_if<_PCCFP<_U1, _U2>::template
+			   _ConstructiblePair<_U1, _U2>()
+	                 && _PCCFP<_U1, _U2>::template
+			   _ImplicitlyConvertiblePair<_U1, _U2>(),
+			  bool>::type=true>
+        constexpr pair(const pair<_U1, _U2>& __p)
+        : first(__p.first), second(__p.second) { }
+
+      template<typename _U1, typename _U2, typename
+	       enable_if<_PCCFP<_U1, _U2>::template
+			   _ConstructiblePair<_U1, _U2>()
+			 && !_PCCFP<_U1, _U2>::template
+			   _ImplicitlyConvertiblePair<_U1, _U2>(),
+                         bool>::type=false>
+	explicit constexpr pair(const pair<_U1, _U2>& __p)
+	: first(__p.first), second(__p.second) { }
+
+#if _GLIBCXX_USE_DEPRECATED
+#if defined(__DEPRECATED)
+# define _GLIBCXX_DEPRECATED_PAIR_CTOR \
+      __attribute__ ((__deprecated__ ("use 'nullptr' instead of '0' to " \
+				      "initialize std::pair of move-only " \
+				      "type and pointer")))
+#else
+# define _GLIBCXX_DEPRECATED_PAIR_CTOR
+#endif
+
+    private:
+      /// @cond undocumented
+
+      // A type which can be constructed from literal zero, but not nullptr
+      struct __zero_as_null_pointer_constant
+      {
+	__zero_as_null_pointer_constant(int __zero_as_null_pointer_constant::*)
+	{ }
+	template<typename _Tp,
+		 typename = __enable_if_t<is_null_pointer<_Tp>::value>>
+	__zero_as_null_pointer_constant(_Tp) = delete;
+      };
+      /// @endcond
+    public:
+
+      // Deprecated extensions to DR 811.
+      // These allow construction from an rvalue and a literal zero,
+      // in cases where the standard says the zero should be deduced as int
+      template<typename _U1,
+	       __enable_if_t<__and_<__not_<is_reference<_U1>>,
+				    is_pointer<_T2>,
+				    is_constructible<_T1, _U1>,
+				    __not_<is_constructible<_T1, const _U1&>>,
+				    is_convertible<_U1, _T1>>::value,
+			     bool> = true>
+	_GLIBCXX_DEPRECATED_PAIR_CTOR
+	constexpr
+	pair(_U1&& __x, __zero_as_null_pointer_constant, ...)
+	: first(std::forward<_U1>(__x)), second(nullptr) { }
+
+      template<typename _U1,
+	       __enable_if_t<__and_<__not_<is_reference<_U1>>,
+				    is_pointer<_T2>,
+				    is_constructible<_T1, _U1>,
+				    __not_<is_constructible<_T1, const _U1&>>,
+				    __not_<is_convertible<_U1, _T1>>>::value,
+			     bool> = false>
+	_GLIBCXX_DEPRECATED_PAIR_CTOR
+	explicit constexpr
+	pair(_U1&& __x, __zero_as_null_pointer_constant, ...)
+	: first(std::forward<_U1>(__x)), second(nullptr) { }
+
+      template<typename _U2,
+	       __enable_if_t<__and_<is_pointer<_T1>,
+				    __not_<is_reference<_U2>>,
+				    is_constructible<_T2, _U2>,
+				    __not_<is_constructible<_T2, const _U2&>>,
+				    is_convertible<_U2, _T2>>::value,
+			     bool> = true>
+	_GLIBCXX_DEPRECATED_PAIR_CTOR
+	constexpr
+	pair(__zero_as_null_pointer_constant, _U2&& __y, ...)
+	: first(nullptr), second(std::forward<_U2>(__y)) { }
+
+      template<typename _U2,
+	       __enable_if_t<__and_<is_pointer<_T1>,
+				    __not_<is_reference<_U2>>,
+				    is_constructible<_T2, _U2>,
+				    __not_<is_constructible<_T2, const _U2&>>,
+				    __not_<is_convertible<_U2, _T2>>>::value,
+			     bool> = false>
+	_GLIBCXX_DEPRECATED_PAIR_CTOR
+	explicit constexpr
+	pair(__zero_as_null_pointer_constant, _U2&& __y, ...)
+	: first(nullptr), second(std::forward<_U2>(__y)) { }
+#undef _GLIBCXX_DEPRECATED_PAIR_CTOR
+#endif
+
+      template<typename _U1, typename _U2, typename
+	       enable_if<_PCCP::template
+			   _MoveConstructiblePair<_U1, _U2>()
+			  && _PCCP::template
+			   _ImplicitlyMoveConvertiblePair<_U1, _U2>(),
+                         bool>::type=true>
+	constexpr pair(_U1&& __x, _U2&& __y)
+	: first(std::forward<_U1>(__x)), second(std::forward<_U2>(__y)) { }
+
+      template<typename _U1, typename _U2, typename
+	       enable_if<_PCCP::template
+			   _MoveConstructiblePair<_U1, _U2>()
+			  && !_PCCP::template
+			   _ImplicitlyMoveConvertiblePair<_U1, _U2>(),
+                         bool>::type=false>
+	explicit constexpr pair(_U1&& __x, _U2&& __y)
+	: first(std::forward<_U1>(__x)), second(std::forward<_U2>(__y)) { }
+
+
+      template<typename _U1, typename _U2, typename
+	       enable_if<_PCCFP<_U1, _U2>::template
+			   _MoveConstructiblePair<_U1, _U2>()
+			  && _PCCFP<_U1, _U2>::template
+			   _ImplicitlyMoveConvertiblePair<_U1, _U2>(),
+                         bool>::type=true>
+	constexpr pair(pair<_U1, _U2>&& __p)
+	: first(std::forward<_U1>(__p.first)),
+	  second(std::forward<_U2>(__p.second)) { }
+
+      template<typename _U1, typename _U2, typename
+	       enable_if<_PCCFP<_U1, _U2>::template
+			   _MoveConstructiblePair<_U1, _U2>()
+			  && !_PCCFP<_U1, _U2>::template
+			   _ImplicitlyMoveConvertiblePair<_U1, _U2>(),
+                         bool>::type=false>
+	explicit constexpr pair(pair<_U1, _U2>&& __p)
+	: first(std::forward<_U1>(__p.first)),
+	  second(std::forward<_U2>(__p.second)) { }
+
+      pair&
+      operator=(__conditional_t<__and_<is_copy_assignable<_T1>,
+				       is_copy_assignable<_T2>>::value,
+				const pair&, const __nonesuch&> __p)
+      {
+	first = __p.first;
+	second = __p.second;
+	return *this;
+      }
+
+      pair&
+      operator=(__conditional_t<__and_<is_move_assignable<_T1>,
+				       is_move_assignable<_T2>>::value,
+				pair&&, __nonesuch&&> __p)
+      noexcept(__and_<is_nothrow_move_assignable<_T1>,
+		      is_nothrow_move_assignable<_T2>>::value)
+      {
+	first = std::forward<first_type>(__p.first);
+	second = std::forward<second_type>(__p.second);
+	return *this;
+      }
+
+      template<typename _U1, typename _U2>
+	typename enable_if<__and_<is_assignable<_T1&, const _U1&>,
+				  is_assignable<_T2&, const _U2&>>::value,
+			   pair&>::type
+	operator=(const pair<_U1, _U2>& __p)
+	{
+	  first = __p.first;
+	  second = __p.second;
+	  return *this;
+	}
+
+      template<typename _U1, typename _U2>
+	typename enable_if<__and_<is_assignable<_T1&, _U1&&>,
+				  is_assignable<_T2&, _U2&&>>::value,
+			   pair&>::type
+	operator=(pair<_U1, _U2>&& __p)
+	{
+	  first = std::forward<_U1>(__p.first);
+	  second = std::forward<_U2>(__p.second);
+	  return *this;
+	}
+#endif // lib concepts
+#else
+      // C++03 implementation
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 265.  std::pair::pair() effects overly restrictive
+      /** The default constructor creates @c first and @c second using their
+       *  respective default constructors.  */
+      pair() : first(), second() { }
+
+      /// Two objects may be passed to a `pair` constructor to be copied.
+      pair(const _T1& __a, const _T2& __b)
+      : first(__a), second(__b) { }
+
+      /// Templated constructor to convert from other pairs.
+      template<typename _U1, typename _U2>
+	pair(const pair<_U1, _U2>& __p)
+	: first(__p.first), second(__p.second) { }
+#endif // C++11
+    };
+
+  /// @relates pair @{
+
+#if __cpp_deduction_guides >= 201606
+  template<typename _T1, typename _T2> pair(_T1, _T2) -> pair<_T1, _T2>;
+#endif
+
+  /// Two pairs of the same type are equal iff their members are equal.
+  template<typename _T1, typename _T2>
+    inline _GLIBCXX_CONSTEXPR bool
+    operator==(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
+    { return __x.first == __y.first && __x.second == __y.second; }
+
+#if __cpp_lib_three_way_comparison && __cpp_lib_concepts
+  template<typename _T1, typename _T2>
+    constexpr common_comparison_category_t<__detail::__synth3way_t<_T1>,
+					   __detail::__synth3way_t<_T2>>
+    operator<=>(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
+    {
+      if (auto __c = __detail::__synth3way(__x.first, __y.first); __c != 0)
+	return __c;
+      return __detail::__synth3way(__x.second, __y.second);
+    }
+#else
+  /** Defines a lexicographical order for pairs.
+   *
+   * For two pairs of the same type, `P` is ordered before `Q` if
+   * `P.first` is less than `Q.first`, or if `P.first` and `Q.first`
+   * are equivalent (neither is less than the other) and `P.second` is less
+   * than `Q.second`.
+  */
+  template<typename _T1, typename _T2>
+    inline _GLIBCXX_CONSTEXPR bool
+    operator<(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
+    { return __x.first < __y.first
+	     || (!(__y.first < __x.first) && __x.second < __y.second); }
+
+  /// Uses @c operator== to find the result.
+  template<typename _T1, typename _T2>
+    inline _GLIBCXX_CONSTEXPR bool
+    operator!=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
+    { return !(__x == __y); }
+
+  /// Uses @c operator< to find the result.
+  template<typename _T1, typename _T2>
+    inline _GLIBCXX_CONSTEXPR bool
+    operator>(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
+    { return __y < __x; }
+
+  /// Uses @c operator< to find the result.
+  template<typename _T1, typename _T2>
+    inline _GLIBCXX_CONSTEXPR bool
+    operator<=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
+    { return !(__y < __x); }
+
+  /// Uses @c operator< to find the result.
+  template<typename _T1, typename _T2>
+    inline _GLIBCXX_CONSTEXPR bool
+    operator>=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
+    { return !(__x < __y); }
+#endif // !(three_way_comparison && concepts)
+
+#if __cplusplus >= 201103L
+  /** Swap overload for pairs. Calls std::pair::swap().
+   *
+   * @note This std::swap overload is not declared in C++03 mode,
+   * which has performance implications, e.g. see https://gcc.gnu.org/PR38466
+  */
+  template<typename _T1, typename _T2>
+    _GLIBCXX20_CONSTEXPR inline
+#if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11
+    // Constrained free swap overload, see p0185r1
+    typename enable_if<__and_<__is_swappable<_T1>,
+                              __is_swappable<_T2>>::value>::type
+#else
+    void
+#endif
+    swap(pair<_T1, _T2>& __x, pair<_T1, _T2>& __y)
+    noexcept(noexcept(__x.swap(__y)))
+    { __x.swap(__y); }
+
+#if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11
+  template<typename _T1, typename _T2>
+    typename enable_if<!__and_<__is_swappable<_T1>,
+			       __is_swappable<_T2>>::value>::type
+    swap(pair<_T1, _T2>&, pair<_T1, _T2>&) = delete;
+#endif
+#endif // __cplusplus >= 201103L
+
+  /// @} relates pair
+
+  /**
+   *  @brief A convenience wrapper for creating a pair from two objects.
+   *  @param  __x  The first object.
+   *  @param  __y  The second object.
+   *  @return   A newly-constructed pair<> object of the appropriate type.
+   *
+   *  The C++98 standard says the objects are passed by reference-to-const,
+   *  but C++03 says they are passed by value (this was LWG issue #181).
+   *
+   *  Since C++11 they have been passed by forwarding reference and then
+   *  forwarded to the new members of the pair. To create a pair with a
+   *  member of reference type, pass a `reference_wrapper` to this function.
+   */
+  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+  // 181.  make_pair() unintended behavior
+#if __cplusplus >= 201103L
+  // NB: DR 706.
+  template<typename _T1, typename _T2>
+    constexpr pair<typename __decay_and_strip<_T1>::__type,
+                   typename __decay_and_strip<_T2>::__type>
+    make_pair(_T1&& __x, _T2&& __y)
+    {
+      typedef typename __decay_and_strip<_T1>::__type __ds_type1;
+      typedef typename __decay_and_strip<_T2>::__type __ds_type2;
+      typedef pair<__ds_type1, __ds_type2> 	      __pair_type;
+      return __pair_type(std::forward<_T1>(__x), std::forward<_T2>(__y));
+    }
+#else
+  template<typename _T1, typename _T2>
+    inline pair<_T1, _T2>
+    make_pair(_T1 __x, _T2 __y)
+    { return pair<_T1, _T2>(__x, __y); }
+#endif
+
+  /// @}
+
+#if __cplusplus >= 201103L
+  // Various functions which give std::pair a tuple-like interface.
+
+  template<typename _T1, typename _T2>
+    struct __is_tuple_like_impl<pair<_T1, _T2>> : true_type
+    { };
+
+  /// Partial specialization for std::pair
+  template<class _Tp1, class _Tp2>
+    struct tuple_size<pair<_Tp1, _Tp2>>
+    : public integral_constant<size_t, 2> { };
+
+  /// Partial specialization for std::pair
+  template<class _Tp1, class _Tp2>
+    struct tuple_element<0, pair<_Tp1, _Tp2>>
+    { typedef _Tp1 type; };
+
+  /// Partial specialization for std::pair
+  template<class _Tp1, class _Tp2>
+    struct tuple_element<1, pair<_Tp1, _Tp2>>
+    { typedef _Tp2 type; };
+
+#if __cplusplus >= 201703L
+  template<typename _Tp1, typename _Tp2>
+    inline constexpr size_t tuple_size_v<pair<_Tp1, _Tp2>> = 2;
+
+  template<typename _Tp1, typename _Tp2>
+    inline constexpr size_t tuple_size_v<const pair<_Tp1, _Tp2>> = 2;
+
+  template<typename _Tp>
+    inline constexpr bool __is_pair = false;
+
+  template<typename _Tp, typename _Up>
+    inline constexpr bool __is_pair<pair<_Tp, _Up>> = true;
+
+  template<typename _Tp, typename _Up>
+    inline constexpr bool __is_pair<const pair<_Tp, _Up>> = true;
+#endif
+
+  /// @cond undocumented
+  template<size_t _Int>
+    struct __pair_get;
+
+  template<>
+    struct __pair_get<0>
+    {
+      template<typename _Tp1, typename _Tp2>
+	static constexpr _Tp1&
+	__get(pair<_Tp1, _Tp2>& __pair) noexcept
+	{ return __pair.first; }
+
+      template<typename _Tp1, typename _Tp2>
+	static constexpr _Tp1&&
+	__move_get(pair<_Tp1, _Tp2>&& __pair) noexcept
+	{ return std::forward<_Tp1>(__pair.first); }
+
+      template<typename _Tp1, typename _Tp2>
+	static constexpr const _Tp1&
+	__const_get(const pair<_Tp1, _Tp2>& __pair) noexcept
+	{ return __pair.first; }
+
+      template<typename _Tp1, typename _Tp2>
+	static constexpr const _Tp1&&
+	__const_move_get(const pair<_Tp1, _Tp2>&& __pair) noexcept
+	{ return std::forward<const _Tp1>(__pair.first); }
+    };
+
+  template<>
+    struct __pair_get<1>
+    {
+      template<typename _Tp1, typename _Tp2>
+	static constexpr _Tp2&
+	__get(pair<_Tp1, _Tp2>& __pair) noexcept
+	{ return __pair.second; }
+
+      template<typename _Tp1, typename _Tp2>
+	static constexpr _Tp2&&
+	__move_get(pair<_Tp1, _Tp2>&& __pair) noexcept
+	{ return std::forward<_Tp2>(__pair.second); }
+
+      template<typename _Tp1, typename _Tp2>
+	static constexpr const _Tp2&
+	__const_get(const pair<_Tp1, _Tp2>& __pair) noexcept
+	{ return __pair.second; }
+
+      template<typename _Tp1, typename _Tp2>
+	static constexpr const _Tp2&&
+	__const_move_get(const pair<_Tp1, _Tp2>&& __pair) noexcept
+	{ return std::forward<const _Tp2>(__pair.second); }
+    };
+  /// @endcond
+
+  /** @{
+   * std::get overloads for accessing members of std::pair
+   */
+
+  template<size_t _Int, class _Tp1, class _Tp2>
+    constexpr typename tuple_element<_Int, pair<_Tp1, _Tp2>>::type&
+    get(pair<_Tp1, _Tp2>& __in) noexcept
+    { return __pair_get<_Int>::__get(__in); }
+
+  template<size_t _Int, class _Tp1, class _Tp2>
+    constexpr typename tuple_element<_Int, pair<_Tp1, _Tp2>>::type&&
+    get(pair<_Tp1, _Tp2>&& __in) noexcept
+    { return __pair_get<_Int>::__move_get(std::move(__in)); }
+
+  template<size_t _Int, class _Tp1, class _Tp2>
+    constexpr const typename tuple_element<_Int, pair<_Tp1, _Tp2>>::type&
+    get(const pair<_Tp1, _Tp2>& __in) noexcept
+    { return __pair_get<_Int>::__const_get(__in); }
+
+  template<size_t _Int, class _Tp1, class _Tp2>
+    constexpr const typename tuple_element<_Int, pair<_Tp1, _Tp2>>::type&&
+    get(const pair<_Tp1, _Tp2>&& __in) noexcept
+    { return __pair_get<_Int>::__const_move_get(std::move(__in)); }
+
+#if __cplusplus >= 201402L
+
+#define __cpp_lib_tuples_by_type 201304L
+
+  template <typename _Tp, typename _Up>
+    constexpr _Tp&
+    get(pair<_Tp, _Up>& __p) noexcept
+    { return __p.first; }
+
+  template <typename _Tp, typename _Up>
+    constexpr const _Tp&
+    get(const pair<_Tp, _Up>& __p) noexcept
+    { return __p.first; }
+
+  template <typename _Tp, typename _Up>
+    constexpr _Tp&&
+    get(pair<_Tp, _Up>&& __p) noexcept
+    { return std::move(__p.first); }
+
+  template <typename _Tp, typename _Up>
+    constexpr const _Tp&&
+    get(const pair<_Tp, _Up>&& __p) noexcept
+    { return std::move(__p.first); }
+
+  template <typename _Tp, typename _Up>
+    constexpr _Tp&
+    get(pair<_Up, _Tp>& __p) noexcept
+    { return __p.second; }
+
+  template <typename _Tp, typename _Up>
+    constexpr const _Tp&
+    get(const pair<_Up, _Tp>& __p) noexcept
+    { return __p.second; }
+
+  template <typename _Tp, typename _Up>
+    constexpr _Tp&&
+    get(pair<_Up, _Tp>&& __p) noexcept
+    { return std::move(__p.second); }
+
+  template <typename _Tp, typename _Up>
+    constexpr const _Tp&&
+    get(const pair<_Up, _Tp>&& __p) noexcept
+    { return std::move(__p.second); }
+
+#endif // C++14
+  /// @}
+#endif // C++11
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif /* _STL_PAIR_H */
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@@ -0,0 +1,850 @@
+// Queue implementation -*- C++ -*-
+
+// Copyright (C) 2001-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/*
+ *
+ * Copyright (c) 1994
+ * Hewlett-Packard Company
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Hewlett-Packard Company makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ *
+ *
+ * Copyright (c) 1996,1997
+ * Silicon Graphics Computer Systems, Inc.
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Silicon Graphics makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ */
+
+/** @file bits/stl_queue.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{queue}
+ */
+
+#ifndef _STL_QUEUE_H
+#define _STL_QUEUE_H 1
+
+#include <bits/concept_check.h>
+#include <debug/debug.h>
+#if __cplusplus >= 201103L
+# include <bits/uses_allocator.h>
+#endif
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /**
+   *  @brief  A standard container giving FIFO behavior.
+   *
+   *  @ingroup sequences
+   *
+   *  @tparam _Tp  Type of element.
+   *  @tparam _Sequence  Type of underlying sequence, defaults to deque<_Tp>.
+   *
+   *  Meets many of the requirements of a
+   *  <a href="tables.html#65">container</a>,
+   *  but does not define anything to do with iterators.  Very few of the
+   *  other standard container interfaces are defined.
+   *
+   *  This is not a true container, but an @e adaptor.  It holds another
+   *  container, and provides a wrapper interface to that container.  The
+   *  wrapper is what enforces strict first-in-first-out %queue behavior.
+   *
+   *  The second template parameter defines the type of the underlying
+   *  sequence/container.  It defaults to std::deque, but it can be any type
+   *  that supports @c front, @c back, @c push_back, and @c pop_front,
+   *  such as std::list or an appropriate user-defined type.
+   *
+   *  Members not found in @a normal containers are @c container_type,
+   *  which is a typedef for the second Sequence parameter, and @c push and
+   *  @c pop, which are standard %queue/FIFO operations.
+  */
+  template<typename _Tp, typename _Sequence = deque<_Tp> >
+    class queue
+    {
+#ifdef _GLIBCXX_CONCEPT_CHECKS
+      // concept requirements
+      typedef typename _Sequence::value_type _Sequence_value_type;
+# if __cplusplus < 201103L
+      __glibcxx_class_requires(_Tp, _SGIAssignableConcept)
+# endif
+      __glibcxx_class_requires(_Sequence, _FrontInsertionSequenceConcept)
+      __glibcxx_class_requires(_Sequence, _BackInsertionSequenceConcept)
+      __glibcxx_class_requires2(_Tp, _Sequence_value_type, _SameTypeConcept)
+#endif
+
+      template<typename _Tp1, typename _Seq1>
+	friend bool
+	operator==(const queue<_Tp1, _Seq1>&, const queue<_Tp1, _Seq1>&);
+
+      template<typename _Tp1, typename _Seq1>
+	friend bool
+	operator<(const queue<_Tp1, _Seq1>&, const queue<_Tp1, _Seq1>&);
+
+#if __cpp_lib_three_way_comparison
+      template<typename _Tp1, three_way_comparable _Seq1>
+	friend compare_three_way_result_t<_Seq1>
+	operator<=>(const queue<_Tp1, _Seq1>&, const queue<_Tp1, _Seq1>&);
+#endif
+
+#if __cplusplus >= 201103L
+      template<typename _Alloc>
+	using _Uses = typename
+	  enable_if<uses_allocator<_Sequence, _Alloc>::value>::type;
+
+#if __cplusplus >= 201703L
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 2566. Requirements on the first template parameter of container
+      // adaptors
+      static_assert(is_same<_Tp, typename _Sequence::value_type>::value,
+	  "value_type must be the same as the underlying container");
+#endif // C++17
+#endif // C++11
+
+    public:
+      typedef typename	_Sequence::value_type		value_type;
+      typedef typename	_Sequence::reference		reference;
+      typedef typename	_Sequence::const_reference	const_reference;
+      typedef typename	_Sequence::size_type		size_type;
+      typedef		_Sequence			container_type;
+
+    protected:
+      /*  Maintainers wondering why this isn't uglified as per style
+       *  guidelines should note that this name is specified in the standard,
+       *  C++98 [23.2.3.1].
+       *  (Why? Presumably for the same reason that it's protected instead
+       *  of private: to allow derivation.  But none of the other
+       *  containers allow for derivation.  Odd.)
+       */
+       ///  @c c is the underlying container.
+      _Sequence c;
+
+    public:
+      /**
+       *  @brief  Default constructor creates no elements.
+       */
+#if __cplusplus < 201103L
+      explicit
+      queue(const _Sequence& __c = _Sequence())
+      : c(__c) { }
+#else
+      template<typename _Seq = _Sequence, typename _Requires = typename
+	       enable_if<is_default_constructible<_Seq>::value>::type>
+	queue()
+	: c() { }
+
+      explicit
+      queue(const _Sequence& __c)
+      : c(__c) { }
+
+      explicit
+      queue(_Sequence&& __c)
+      : c(std::move(__c)) { }
+
+      template<typename _Alloc, typename _Requires = _Uses<_Alloc>>
+	explicit
+	queue(const _Alloc& __a)
+	: c(__a) { }
+
+      template<typename _Alloc, typename _Requires = _Uses<_Alloc>>
+	queue(const _Sequence& __c, const _Alloc& __a)
+	: c(__c, __a) { }
+
+      template<typename _Alloc, typename _Requires = _Uses<_Alloc>>
+	queue(_Sequence&& __c, const _Alloc& __a)
+	: c(std::move(__c), __a) { }
+
+      template<typename _Alloc, typename _Requires = _Uses<_Alloc>>
+	queue(const queue& __q, const _Alloc& __a)
+	: c(__q.c, __a) { }
+
+      template<typename _Alloc, typename _Requires = _Uses<_Alloc>>
+	queue(queue&& __q, const _Alloc& __a)
+	: c(std::move(__q.c), __a) { }
+
+#if __cplusplus > 202002L
+#define __cpp_lib_adaptor_iterator_pair_constructor 202106L
+
+      template<typename _InputIterator,
+	       typename = _RequireInputIter<_InputIterator>>
+	queue(_InputIterator __first, _InputIterator __last)
+	: c(__first, __last) { }
+
+      template<typename _InputIterator, typename _Alloc,
+	       typename = _RequireInputIter<_InputIterator>,
+	       typename = _Uses<_Alloc>>
+	queue(_InputIterator __first, _InputIterator __last, const _Alloc& __a)
+	: c(__first, __last, __a) { }
+#endif
+#endif
+
+      /**
+       *  Returns true if the %queue is empty.
+       */
+      _GLIBCXX_NODISCARD bool
+      empty() const
+      { return c.empty(); }
+
+      /**  Returns the number of elements in the %queue.  */
+      _GLIBCXX_NODISCARD
+      size_type
+      size() const
+      { return c.size(); }
+
+      /**
+       *  Returns a read/write reference to the data at the first
+       *  element of the %queue.
+       */
+      _GLIBCXX_NODISCARD
+      reference
+      front()
+      {
+	__glibcxx_requires_nonempty();
+	return c.front();
+      }
+
+      /**
+       *  Returns a read-only (constant) reference to the data at the first
+       *  element of the %queue.
+       */
+      _GLIBCXX_NODISCARD
+      const_reference
+      front() const
+      {
+	__glibcxx_requires_nonempty();
+	return c.front();
+      }
+
+      /**
+       *  Returns a read/write reference to the data at the last
+       *  element of the %queue.
+       */
+      _GLIBCXX_NODISCARD
+      reference
+      back()
+      {
+	__glibcxx_requires_nonempty();
+	return c.back();
+      }
+
+      /**
+       *  Returns a read-only (constant) reference to the data at the last
+       *  element of the %queue.
+       */
+      _GLIBCXX_NODISCARD
+      const_reference
+      back() const
+      {
+	__glibcxx_requires_nonempty();
+	return c.back();
+      }
+
+      /**
+       *  @brief  Add data to the end of the %queue.
+       *  @param  __x  Data to be added.
+       *
+       *  This is a typical %queue operation.  The function creates an
+       *  element at the end of the %queue and assigns the given data
+       *  to it.  The time complexity of the operation depends on the
+       *  underlying sequence.
+       */
+      void
+      push(const value_type& __x)
+      { c.push_back(__x); }
+
+#if __cplusplus >= 201103L
+      void
+      push(value_type&& __x)
+      { c.push_back(std::move(__x)); }
+
+#if __cplusplus > 201402L
+      template<typename... _Args>
+	decltype(auto)
+	emplace(_Args&&... __args)
+	{ return c.emplace_back(std::forward<_Args>(__args)...); }
+#else
+      template<typename... _Args>
+	void
+	emplace(_Args&&... __args)
+	{ c.emplace_back(std::forward<_Args>(__args)...); }
+#endif
+#endif
+
+      /**
+       *  @brief  Removes first element.
+       *
+       *  This is a typical %queue operation.  It shrinks the %queue by one.
+       *  The time complexity of the operation depends on the underlying
+       *  sequence.
+       *
+       *  Note that no data is returned, and if the first element's
+       *  data is needed, it should be retrieved before pop() is
+       *  called.
+       */
+      void
+      pop()
+      {
+	__glibcxx_requires_nonempty();
+	c.pop_front();
+      }
+
+#if __cplusplus >= 201103L
+      void
+      swap(queue& __q)
+#if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11
+      noexcept(__is_nothrow_swappable<_Sequence>::value)
+#else
+      noexcept(__is_nothrow_swappable<_Tp>::value)
+#endif
+      {
+	using std::swap;
+	swap(c, __q.c);
+      }
+#endif // __cplusplus >= 201103L
+    };
+
+#if __cpp_deduction_guides >= 201606
+  template<typename _Container,
+	   typename = _RequireNotAllocator<_Container>>
+    queue(_Container) -> queue<typename _Container::value_type, _Container>;
+
+  template<typename _Container, typename _Allocator,
+	   typename = _RequireNotAllocator<_Container>>
+    queue(_Container, _Allocator)
+    -> queue<typename _Container::value_type, _Container>;
+
+#ifdef __cpp_lib_adaptor_iterator_pair_constructor
+  template<typename _InputIterator,
+	   typename _ValT
+	     = typename iterator_traits<_InputIterator>::value_type,
+	   typename = _RequireInputIter<_InputIterator>>
+    queue(_InputIterator, _InputIterator) -> queue<_ValT>;
+
+  template<typename _InputIterator, typename _Allocator,
+	   typename _ValT
+	     = typename iterator_traits<_InputIterator>::value_type,
+	   typename = _RequireInputIter<_InputIterator>,
+	   typename = _RequireAllocator<_Allocator>>
+    queue(_InputIterator, _InputIterator, _Allocator)
+    -> queue<_ValT, deque<_ValT, _Allocator>>;
+#endif
+#endif
+
+  /**
+   *  @brief  Queue equality comparison.
+   *  @param  __x  A %queue.
+   *  @param  __y  A %queue of the same type as @a __x.
+   *  @return  True iff the size and elements of the queues are equal.
+   *
+   *  This is an equivalence relation.  Complexity and semantics depend on the
+   *  underlying sequence type, but the expected rules are:  this relation is
+   *  linear in the size of the sequences, and queues are considered equivalent
+   *  if their sequences compare equal.
+  */
+  template<typename _Tp, typename _Seq>
+    _GLIBCXX_NODISCARD
+    inline bool
+    operator==(const queue<_Tp, _Seq>& __x, const queue<_Tp, _Seq>& __y)
+    { return __x.c == __y.c; }
+
+  /**
+   *  @brief  Queue ordering relation.
+   *  @param  __x  A %queue.
+   *  @param  __y  A %queue of the same type as @a x.
+   *  @return  True iff @a __x is lexicographically less than @a __y.
+   *
+   *  This is an total ordering relation.  Complexity and semantics
+   *  depend on the underlying sequence type, but the expected rules
+   *  are: this relation is linear in the size of the sequences, the
+   *  elements must be comparable with @c <, and
+   *  std::lexicographical_compare() is usually used to make the
+   *  determination.
+  */
+  template<typename _Tp, typename _Seq>
+    _GLIBCXX_NODISCARD
+    inline bool
+    operator<(const queue<_Tp, _Seq>& __x, const queue<_Tp, _Seq>& __y)
+    { return __x.c < __y.c; }
+
+  /// Based on operator==
+  template<typename _Tp, typename _Seq>
+    _GLIBCXX_NODISCARD
+    inline bool
+    operator!=(const queue<_Tp, _Seq>& __x, const queue<_Tp, _Seq>& __y)
+    { return !(__x == __y); }
+
+  /// Based on operator<
+  template<typename _Tp, typename _Seq>
+    _GLIBCXX_NODISCARD
+    inline bool
+    operator>(const queue<_Tp, _Seq>& __x, const queue<_Tp, _Seq>& __y)
+    { return __y < __x; }
+
+  /// Based on operator<
+  template<typename _Tp, typename _Seq>
+    _GLIBCXX_NODISCARD
+    inline bool
+    operator<=(const queue<_Tp, _Seq>& __x, const queue<_Tp, _Seq>& __y)
+    { return !(__y < __x); }
+
+  /// Based on operator<
+  template<typename _Tp, typename _Seq>
+    _GLIBCXX_NODISCARD
+    inline bool
+    operator>=(const queue<_Tp, _Seq>& __x, const queue<_Tp, _Seq>& __y)
+    { return !(__x < __y); }
+
+#if __cpp_lib_three_way_comparison
+  template<typename _Tp, three_way_comparable _Seq>
+    [[nodiscard]]
+    inline compare_three_way_result_t<_Seq>
+    operator<=>(const queue<_Tp, _Seq>& __x, const queue<_Tp, _Seq>& __y)
+    { return __x.c <=> __y.c; }
+#endif
+
+#if __cplusplus >= 201103L
+  template<typename _Tp, typename _Seq>
+    inline
+#if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11
+    // Constrained free swap overload, see p0185r1
+    typename enable_if<__is_swappable<_Seq>::value>::type
+#else
+    void
+#endif
+    swap(queue<_Tp, _Seq>& __x, queue<_Tp, _Seq>& __y)
+    noexcept(noexcept(__x.swap(__y)))
+    { __x.swap(__y); }
+
+  template<typename _Tp, typename _Seq, typename _Alloc>
+    struct uses_allocator<queue<_Tp, _Seq>, _Alloc>
+    : public uses_allocator<_Seq, _Alloc>::type { };
+#endif // __cplusplus >= 201103L
+
+  /**
+   *  @brief  A standard container automatically sorting its contents.
+   *
+   *  @ingroup sequences
+   *
+   *  @tparam _Tp  Type of element.
+   *  @tparam _Sequence  Type of underlying sequence, defaults to vector<_Tp>.
+   *  @tparam _Compare  Comparison function object type, defaults to
+   *                    less<_Sequence::value_type>.
+   *
+   *  This is not a true container, but an @e adaptor.  It holds
+   *  another container, and provides a wrapper interface to that
+   *  container.  The wrapper is what enforces priority-based sorting
+   *  and %queue behavior.  Very few of the standard container/sequence
+   *  interface requirements are met (e.g., iterators).
+   *
+   *  The second template parameter defines the type of the underlying
+   *  sequence/container.  It defaults to std::vector, but it can be
+   *  any type that supports @c front(), @c push_back, @c pop_back,
+   *  and random-access iterators, such as std::deque or an
+   *  appropriate user-defined type.
+   *
+   *  The third template parameter supplies the means of making
+   *  priority comparisons.  It defaults to @c less<value_type> but
+   *  can be anything defining a strict weak ordering.
+   *
+   *  Members not found in @a normal containers are @c container_type,
+   *  which is a typedef for the second Sequence parameter, and @c
+   *  push, @c pop, and @c top, which are standard %queue operations.
+   *
+   *  @note No equality/comparison operators are provided for
+   *  %priority_queue.
+   *
+   *  @note Sorting of the elements takes place as they are added to,
+   *  and removed from, the %priority_queue using the
+   *  %priority_queue's member functions.  If you access the elements
+   *  by other means, and change their data such that the sorting
+   *  order would be different, the %priority_queue will not re-sort
+   *  the elements for you.  (How could it know to do so?)
+  */
+  template<typename _Tp, typename _Sequence = vector<_Tp>,
+	   typename _Compare  = less<typename _Sequence::value_type> >
+    class priority_queue
+    {
+#ifdef _GLIBCXX_CONCEPT_CHECKS
+      // concept requirements
+      typedef typename _Sequence::value_type _Sequence_value_type;
+# if __cplusplus < 201103L
+      __glibcxx_class_requires(_Tp, _SGIAssignableConcept)
+# endif
+      __glibcxx_class_requires(_Sequence, _SequenceConcept)
+      __glibcxx_class_requires(_Sequence, _RandomAccessContainerConcept)
+      __glibcxx_class_requires2(_Tp, _Sequence_value_type, _SameTypeConcept)
+      __glibcxx_class_requires4(_Compare, bool, _Tp, _Tp,
+				_BinaryFunctionConcept)
+#endif
+
+#if __cplusplus >= 201103L
+      template<typename _Alloc>
+	using _Uses = typename
+	  enable_if<uses_allocator<_Sequence, _Alloc>::value>::type;
+
+#if __cplusplus >= 201703L
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 2566. Requirements on the first template parameter of container
+      // adaptors
+      static_assert(is_same<_Tp, typename _Sequence::value_type>::value,
+	  "value_type must be the same as the underlying container");
+#endif // C++17
+#endif // C++11
+
+    public:
+      typedef typename	_Sequence::value_type		value_type;
+      typedef typename	_Sequence::reference		reference;
+      typedef typename	_Sequence::const_reference	const_reference;
+      typedef typename	_Sequence::size_type		size_type;
+      typedef		_Sequence			container_type;
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // DR 2684. priority_queue lacking comparator typedef
+      typedef	       _Compare				value_compare;
+
+    protected:
+      //  See queue::c for notes on these names.
+      _Sequence  c;
+      _Compare   comp;
+
+    public:
+      /**
+       *  @brief  Default constructor creates no elements.
+       */
+#if __cplusplus < 201103L
+      explicit
+      priority_queue(const _Compare& __x = _Compare(),
+		     const _Sequence& __s = _Sequence())
+      : c(__s), comp(__x)
+      { std::make_heap(c.begin(), c.end(), comp); }
+#else
+      template<typename _Seq = _Sequence, typename _Requires = typename
+	       enable_if<__and_<is_default_constructible<_Compare>,
+				is_default_constructible<_Seq>>::value>::type>
+	priority_queue()
+	: c(), comp() { }
+
+      explicit
+      priority_queue(const _Compare& __x, const _Sequence& __s)
+      : c(__s), comp(__x)
+      { std::make_heap(c.begin(), c.end(), comp); }
+
+      explicit
+      priority_queue(const _Compare& __x, _Sequence&& __s = _Sequence())
+      : c(std::move(__s)), comp(__x)
+      { std::make_heap(c.begin(), c.end(), comp); }
+
+      template<typename _Alloc, typename _Requires = _Uses<_Alloc>>
+	explicit
+	priority_queue(const _Alloc& __a)
+	: c(__a), comp() { }
+
+      template<typename _Alloc, typename _Requires = _Uses<_Alloc>>
+	priority_queue(const _Compare& __x, const _Alloc& __a)
+	: c(__a), comp(__x) { }
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 2537. Constructors [...] taking allocators should call make_heap
+      template<typename _Alloc, typename _Requires = _Uses<_Alloc>>
+	priority_queue(const _Compare& __x, const _Sequence& __c,
+		       const _Alloc& __a)
+	: c(__c, __a), comp(__x)
+	{ std::make_heap(c.begin(), c.end(), comp); }
+
+      template<typename _Alloc, typename _Requires = _Uses<_Alloc>>
+	priority_queue(const _Compare& __x, _Sequence&& __c, const _Alloc& __a)
+	: c(std::move(__c), __a), comp(__x)
+	{ std::make_heap(c.begin(), c.end(), comp); }
+
+      template<typename _Alloc, typename _Requires = _Uses<_Alloc>>
+	priority_queue(const priority_queue& __q, const _Alloc& __a)
+	: c(__q.c, __a), comp(__q.comp) { }
+
+      template<typename _Alloc, typename _Requires = _Uses<_Alloc>>
+	priority_queue(priority_queue&& __q, const _Alloc& __a)
+	: c(std::move(__q.c), __a), comp(std::move(__q.comp)) { }
+#endif
+
+      /**
+       *  @brief  Builds a %queue from a range.
+       *  @param  __first  An input iterator.
+       *  @param  __last  An input iterator.
+       *  @param  __x  A comparison functor describing a strict weak ordering.
+       *  @param  __s  An initial sequence with which to start.
+       *
+       *  Begins by copying @a __s, inserting a copy of the elements
+       *  from @a [first,last) into the copy of @a __s, then ordering
+       *  the copy according to @a __x.
+       *
+       *  For more information on function objects, see the
+       *  documentation on @link functors functor base
+       *  classes@endlink.
+       */
+#if __cplusplus < 201103L
+      template<typename _InputIterator>
+	priority_queue(_InputIterator __first, _InputIterator __last,
+		       const _Compare& __x = _Compare(),
+		       const _Sequence& __s = _Sequence())
+	: c(__s), comp(__x)
+	{
+	  __glibcxx_requires_valid_range(__first, __last);
+	  c.insert(c.end(), __first, __last);
+	  std::make_heap(c.begin(), c.end(), comp);
+	}
+#else
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 3529. priority_queue(first, last) should construct c with (first, last)
+      template<typename _InputIterator,
+	       typename = std::_RequireInputIter<_InputIterator>>
+	priority_queue(_InputIterator __first, _InputIterator __last,
+		       const _Compare& __x = _Compare())
+	: c(__first, __last), comp(__x)
+	{ std::make_heap(c.begin(), c.end(), comp); }
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 3522. Missing requirement on InputIterator template parameter
+      template<typename _InputIterator,
+	       typename = std::_RequireInputIter<_InputIterator>>
+	priority_queue(_InputIterator __first, _InputIterator __last,
+		       const _Compare& __x, const _Sequence& __s)
+	: c(__s), comp(__x)
+	{
+	  __glibcxx_requires_valid_range(__first, __last);
+	  c.insert(c.end(), __first, __last);
+	  std::make_heap(c.begin(), c.end(), comp);
+	}
+
+      template<typename _InputIterator,
+	       typename = std::_RequireInputIter<_InputIterator>>
+	priority_queue(_InputIterator __first, _InputIterator __last,
+		       const _Compare& __x, _Sequence&& __s)
+	: c(std::move(__s)), comp(__x)
+	{
+	  __glibcxx_requires_valid_range(__first, __last);
+	  c.insert(c.end(), __first, __last);
+	  std::make_heap(c.begin(), c.end(), comp);
+	}
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 3506. Missing allocator-extended constructors for priority_queue
+      template<typename _InputIterator, typename _Alloc,
+	       typename = std::_RequireInputIter<_InputIterator>,
+	       typename _Requires = _Uses<_Alloc>>
+	priority_queue(_InputIterator __first, _InputIterator __last,
+		       const _Alloc& __alloc)
+	: c(__first, __last, __alloc), comp()
+	{ std::make_heap(c.begin(), c.end(), comp); }
+
+      template<typename _InputIterator, typename _Alloc,
+	       typename = std::_RequireInputIter<_InputIterator>,
+	       typename _Requires = _Uses<_Alloc>>
+	priority_queue(_InputIterator __first, _InputIterator __last,
+		       const _Compare& __x, const _Alloc& __alloc)
+	: c(__first, __last, __alloc), comp(__x)
+	{ std::make_heap(c.begin(), c.end(), comp); }
+
+      template<typename _InputIterator, typename _Alloc,
+	       typename = std::_RequireInputIter<_InputIterator>,
+	       typename _Requires = _Uses<_Alloc>>
+	priority_queue(_InputIterator __first, _InputIterator __last,
+		       const _Compare& __x, const _Sequence& __s,
+		       const _Alloc& __alloc)
+	: c(__s, __alloc), comp(__x)
+	{
+	  __glibcxx_requires_valid_range(__first, __last);
+	  c.insert(c.end(), __first, __last);
+	  std::make_heap(c.begin(), c.end(), comp);
+	}
+
+      template<typename _InputIterator, typename _Alloc,
+	       typename _Requires = _Uses<_Alloc>>
+	priority_queue(_InputIterator __first, _InputIterator __last,
+		       const _Compare& __x, _Sequence&& __s,
+		       const _Alloc& __alloc)
+	: c(std::move(__s), __alloc), comp(__x)
+	{
+	  __glibcxx_requires_valid_range(__first, __last);
+	  c.insert(c.end(), __first, __last);
+	  std::make_heap(c.begin(), c.end(), comp);
+	}
+#endif
+
+      /**
+       *  Returns true if the %queue is empty.
+       */
+      _GLIBCXX_NODISCARD bool
+      empty() const
+      { return c.empty(); }
+
+      /**  Returns the number of elements in the %queue.  */
+      _GLIBCXX_NODISCARD
+      size_type
+      size() const
+      { return c.size(); }
+
+      /**
+       *  Returns a read-only (constant) reference to the data at the first
+       *  element of the %queue.
+       */
+      _GLIBCXX_NODISCARD
+      const_reference
+      top() const
+      {
+	__glibcxx_requires_nonempty();
+	return c.front();
+      }
+
+      /**
+       *  @brief  Add data to the %queue.
+       *  @param  __x  Data to be added.
+       *
+       *  This is a typical %queue operation.
+       *  The time complexity of the operation depends on the underlying
+       *  sequence.
+       */
+      void
+      push(const value_type& __x)
+      {
+	c.push_back(__x);
+	std::push_heap(c.begin(), c.end(), comp);
+      }
+
+#if __cplusplus >= 201103L
+      void
+      push(value_type&& __x)
+      {
+	c.push_back(std::move(__x));
+	std::push_heap(c.begin(), c.end(), comp);
+      }
+
+      template<typename... _Args>
+	void
+	emplace(_Args&&... __args)
+	{
+	  c.emplace_back(std::forward<_Args>(__args)...);
+	  std::push_heap(c.begin(), c.end(), comp);
+	}
+#endif
+
+      /**
+       *  @brief  Removes first element.
+       *
+       *  This is a typical %queue operation.  It shrinks the %queue
+       *  by one.  The time complexity of the operation depends on the
+       *  underlying sequence.
+       *
+       *  Note that no data is returned, and if the first element's
+       *  data is needed, it should be retrieved before pop() is
+       *  called.
+       */
+      void
+      pop()
+      {
+	__glibcxx_requires_nonempty();
+	std::pop_heap(c.begin(), c.end(), comp);
+	c.pop_back();
+      }
+
+#if __cplusplus >= 201103L
+      void
+      swap(priority_queue& __pq)
+      noexcept(__and_<
+#if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11
+		 __is_nothrow_swappable<_Sequence>,
+#else
+		 __is_nothrow_swappable<_Tp>,
+#endif
+		 __is_nothrow_swappable<_Compare>
+	       >::value)
+      {
+	using std::swap;
+	swap(c, __pq.c);
+	swap(comp, __pq.comp);
+      }
+#endif // __cplusplus >= 201103L
+    };
+
+#if __cpp_deduction_guides >= 201606
+  template<typename _Compare, typename _Container,
+	   typename = _RequireNotAllocator<_Compare>,
+	   typename = _RequireNotAllocator<_Container>>
+    priority_queue(_Compare, _Container)
+    -> priority_queue<typename _Container::value_type, _Container, _Compare>;
+
+  template<typename _InputIterator, typename _ValT
+	   = typename iterator_traits<_InputIterator>::value_type,
+	   typename _Compare = less<_ValT>,
+	   typename _Container = vector<_ValT>,
+	   typename = _RequireInputIter<_InputIterator>,
+	   typename = _RequireNotAllocator<_Compare>,
+	   typename = _RequireNotAllocator<_Container>>
+    priority_queue(_InputIterator, _InputIterator, _Compare = _Compare(),
+		   _Container = _Container())
+    -> priority_queue<_ValT, _Container, _Compare>;
+
+  template<typename _Compare, typename _Container, typename _Allocator,
+	   typename = _RequireNotAllocator<_Compare>,
+	   typename = _RequireNotAllocator<_Container>>
+    priority_queue(_Compare, _Container, _Allocator)
+    -> priority_queue<typename _Container::value_type, _Container, _Compare>;
+#endif
+
+  // No equality/comparison operators are provided for priority_queue.
+
+#if __cplusplus >= 201103L
+  template<typename _Tp, typename _Sequence, typename _Compare>
+    inline
+#if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11
+    // Constrained free swap overload, see p0185r1
+    typename enable_if<__and_<__is_swappable<_Sequence>,
+			      __is_swappable<_Compare>>::value>::type
+#else
+    void
+#endif
+    swap(priority_queue<_Tp, _Sequence, _Compare>& __x,
+	 priority_queue<_Tp, _Sequence, _Compare>& __y)
+    noexcept(noexcept(__x.swap(__y)))
+    { __x.swap(__y); }
+
+  template<typename _Tp, typename _Sequence, typename _Compare,
+	   typename _Alloc>
+    struct uses_allocator<priority_queue<_Tp, _Sequence, _Compare>, _Alloc>
+    : public uses_allocator<_Sequence, _Alloc>::type { };
+#endif // __cplusplus >= 201103L
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif /* _STL_QUEUE_H */
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@@ -0,0 +1,128 @@
+// -*- C++ -*-
+
+// Copyright (C) 2001-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/*
+ *
+ * Copyright (c) 1994
+ * Hewlett-Packard Company
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Hewlett-Packard Company makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ *
+ *
+ * Copyright (c) 1996
+ * Silicon Graphics Computer Systems, Inc.
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Silicon Graphics makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ */
+
+/** @file bits/stl_raw_storage_iter.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{memory}
+ */
+
+#ifndef _STL_RAW_STORAGE_ITERATOR_H
+#define _STL_RAW_STORAGE_ITERATOR_H 1
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+// Ignore warnings about std::iterator.
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+
+  /**
+   *  This iterator class lets algorithms store their results into
+   *  uninitialized memory.
+  */
+  template <class _OutputIterator, class _Tp>
+    class _GLIBCXX17_DEPRECATED raw_storage_iterator
+    : public iterator<output_iterator_tag, void, void, void, void>
+    {
+    protected:
+      _OutputIterator _M_iter;
+
+    public:
+      explicit
+      raw_storage_iterator(_OutputIterator __x)
+      : _M_iter(__x) {}
+
+      raw_storage_iterator&
+      operator*() { return *this; }
+
+      raw_storage_iterator&
+      operator=(const _Tp& __element)
+      {
+	std::_Construct(std::__addressof(*_M_iter), __element);
+	return *this;
+      }
+
+#if __cplusplus >= 201103L
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 2127. Move-construction with raw_storage_iterator
+      raw_storage_iterator&
+      operator=(_Tp&& __element)
+      {
+	std::_Construct(std::__addressof(*_M_iter), std::move(__element));
+	return *this;
+      }
+#endif
+
+      raw_storage_iterator&
+      operator++()
+      {
+	++_M_iter;
+	return *this;
+      }
+
+      raw_storage_iterator
+      operator++(int)
+      {
+	raw_storage_iterator __tmp = *this;
+	++_M_iter;
+	return __tmp;
+      }
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 2454. Add raw_storage_iterator::base() member
+      _OutputIterator base() const { return _M_iter; }
+    };
+#pragma GCC diagnostic pop
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stl_relops.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stl_relops.h
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@@ -0,0 +1,134 @@
+// std::rel_ops implementation -*- C++ -*-
+
+// Copyright (C) 2001-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the, 2009 Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/*
+ *
+ * Copyright (c) 1994
+ * Hewlett-Packard Company
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Hewlett-Packard Company makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ *
+ * Copyright (c) 1996,1997
+ * Silicon Graphics
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Silicon Graphics makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ *
+ */
+
+/** @file bits/stl_relops.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{utility}
+ *
+ *  This file is only included by `<utility>`, which is required by the
+ *  standard to define namespace `rel_ops` and its contents.
+ */
+
+#ifndef _STL_RELOPS_H
+#define _STL_RELOPS_H 1
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  namespace rel_ops
+  {
+    /** @namespace std::rel_ops
+     *  @brief  The generated relational operators are sequestered here.
+     *
+     *  Libstdc++ headers must not use the contents of `rel_ops`.
+     *  User code should also avoid them, because unconstrained function
+     *  templates are too greedy and can easily cause ambiguities.
+     *
+     *  C++20 default comparisons are a better solution.
+     */
+
+    /**
+     *  @brief Defines @c != for arbitrary types, in terms of @c ==.
+     *  @param  __x  A thing.
+     *  @param  __y  Another thing.
+     *  @return   __x != __y
+     *
+     *  This function uses @c == to determine its result.
+     */
+    template <class _Tp>
+      inline bool
+      operator!=(const _Tp& __x, const _Tp& __y)
+      { return !(__x == __y); }
+
+    /**
+     *  @brief Defines @c > for arbitrary types, in terms of @c <.
+     *  @param  __x  A thing.
+     *  @param  __y  Another thing.
+     *  @return   __x > __y
+     *
+     *  This function uses @c < to determine its result.
+     */
+    template <class _Tp>
+      inline bool
+      operator>(const _Tp& __x, const _Tp& __y)
+      { return __y < __x; }
+
+    /**
+     *  @brief Defines @c <= for arbitrary types, in terms of @c <.
+     *  @param  __x  A thing.
+     *  @param  __y  Another thing.
+     *  @return   __x <= __y
+     *
+     *  This function uses @c < to determine its result.
+     */
+    template <class _Tp>
+      inline bool
+      operator<=(const _Tp& __x, const _Tp& __y)
+      { return !(__y < __x); }
+
+    /**
+     *  @brief Defines @c >= for arbitrary types, in terms of @c <.
+     *  @param  __x  A thing.
+     *  @param  __y  Another thing.
+     *  @return   __x >= __y
+     *
+     *  This function uses @c < to determine its result.
+     */
+    template <class _Tp>
+      inline bool
+      operator>=(const _Tp& __x, const _Tp& __y)
+      { return !(__x < __y); }
+  } // namespace rel_ops
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif /* _STL_RELOPS_H */
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stl_set.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stl_set.h
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stl_set.h
@@ -0,0 +1,1086 @@
+// Set implementation -*- C++ -*-
+
+// Copyright (C) 2001-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/*
+ *
+ * Copyright (c) 1994
+ * Hewlett-Packard Company
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Hewlett-Packard Company makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ *
+ *
+ * Copyright (c) 1996,1997
+ * Silicon Graphics Computer Systems, Inc.
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Silicon Graphics makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ */
+
+/** @file bits/stl_set.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{set}
+ */
+
+#ifndef _STL_SET_H
+#define _STL_SET_H 1
+
+#include <bits/concept_check.h>
+#if __cplusplus >= 201103L
+#include <initializer_list>
+#endif
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+_GLIBCXX_BEGIN_NAMESPACE_CONTAINER
+
+  template<typename _Key, typename _Compare, typename _Alloc>
+    class multiset;
+
+  /**
+   *  @brief A standard container made up of unique keys, which can be
+   *  retrieved in logarithmic time.
+   *
+   *  @ingroup associative_containers
+   *
+   *  @tparam _Key  Type of key objects.
+   *  @tparam _Compare  Comparison function object type, defaults to less<_Key>.
+   *  @tparam _Alloc  Allocator type, defaults to allocator<_Key>.
+   *
+   *  Meets the requirements of a <a href="tables.html#65">container</a>, a
+   *  <a href="tables.html#66">reversible container</a>, and an
+   *  <a href="tables.html#69">associative container</a> (using unique keys).
+   *
+   *  Sets support bidirectional iterators.
+   *
+   *  The private tree data is declared exactly the same way for set and
+   *  multiset; the distinction is made entirely in how the tree functions are
+   *  called (*_unique versus *_equal, same as the standard).
+  */
+  template<typename _Key, typename _Compare = std::less<_Key>,
+	   typename _Alloc = std::allocator<_Key> >
+    class set
+    {
+#ifdef _GLIBCXX_CONCEPT_CHECKS
+      // concept requirements
+      typedef typename _Alloc::value_type		_Alloc_value_type;
+# if __cplusplus < 201103L
+      __glibcxx_class_requires(_Key, _SGIAssignableConcept)
+# endif
+      __glibcxx_class_requires4(_Compare, bool, _Key, _Key,
+				_BinaryFunctionConcept)
+      __glibcxx_class_requires2(_Key, _Alloc_value_type, _SameTypeConcept)
+#endif
+
+#if __cplusplus >= 201103L
+      static_assert(is_same<typename remove_cv<_Key>::type, _Key>::value,
+	  "std::set must have a non-const, non-volatile value_type");
+# if __cplusplus > 201703L || defined __STRICT_ANSI__
+      static_assert(is_same<typename _Alloc::value_type, _Key>::value,
+	  "std::set must have the same value_type as its allocator");
+# endif
+#endif
+
+    public:
+      // typedefs:
+      ///@{
+      /// Public typedefs.
+      typedef _Key     key_type;
+      typedef _Key     value_type;
+      typedef _Compare key_compare;
+      typedef _Compare value_compare;
+      typedef _Alloc   allocator_type;
+      ///@}
+
+    private:
+      typedef typename __gnu_cxx::__alloc_traits<_Alloc>::template
+	rebind<_Key>::other _Key_alloc_type;
+
+      typedef _Rb_tree<key_type, value_type, _Identity<value_type>,
+		       key_compare, _Key_alloc_type> _Rep_type;
+      _Rep_type _M_t;  // Red-black tree representing set.
+
+      typedef __gnu_cxx::__alloc_traits<_Key_alloc_type> _Alloc_traits;
+
+    public:
+      ///@{
+      ///  Iterator-related typedefs.
+      typedef typename _Alloc_traits::pointer		 pointer;
+      typedef typename _Alloc_traits::const_pointer	 const_pointer;
+      typedef typename _Alloc_traits::reference		 reference;
+      typedef typename _Alloc_traits::const_reference	 const_reference;
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // DR 103. set::iterator is required to be modifiable,
+      // but this allows modification of keys.
+      typedef typename _Rep_type::const_iterator	 iterator;
+      typedef typename _Rep_type::const_iterator	 const_iterator;
+      typedef typename _Rep_type::const_reverse_iterator reverse_iterator;
+      typedef typename _Rep_type::const_reverse_iterator const_reverse_iterator;
+      typedef typename _Rep_type::size_type		 size_type;
+      typedef typename _Rep_type::difference_type	 difference_type;
+      ///@}
+
+#if __cplusplus > 201402L
+      using node_type = typename _Rep_type::node_type;
+      using insert_return_type = typename _Rep_type::insert_return_type;
+#endif
+
+      // allocation/deallocation
+      /**
+       *  @brief  Default constructor creates no elements.
+       */
+#if __cplusplus < 201103L
+      set() : _M_t() { }
+#else
+      set() = default;
+#endif
+
+      /**
+       *  @brief  Creates a %set with no elements.
+       *  @param  __comp  Comparator to use.
+       *  @param  __a  An allocator object.
+       */
+      explicit
+      set(const _Compare& __comp,
+	  const allocator_type& __a = allocator_type())
+      : _M_t(__comp, _Key_alloc_type(__a)) { }
+
+      /**
+       *  @brief  Builds a %set from a range.
+       *  @param  __first  An input iterator.
+       *  @param  __last  An input iterator.
+       *
+       *  Create a %set consisting of copies of the elements from
+       *  [__first,__last).  This is linear in N if the range is
+       *  already sorted, and NlogN otherwise (where N is
+       *  distance(__first,__last)).
+       */
+      template<typename _InputIterator>
+	set(_InputIterator __first, _InputIterator __last)
+	: _M_t()
+	{ _M_t._M_insert_range_unique(__first, __last); }
+
+      /**
+       *  @brief  Builds a %set from a range.
+       *  @param  __first  An input iterator.
+       *  @param  __last  An input iterator.
+       *  @param  __comp  A comparison functor.
+       *  @param  __a  An allocator object.
+       *
+       *  Create a %set consisting of copies of the elements from
+       *  [__first,__last).  This is linear in N if the range is
+       *  already sorted, and NlogN otherwise (where N is
+       *  distance(__first,__last)).
+       */
+      template<typename _InputIterator>
+	set(_InputIterator __first, _InputIterator __last,
+	    const _Compare& __comp,
+	    const allocator_type& __a = allocator_type())
+	: _M_t(__comp, _Key_alloc_type(__a))
+	{ _M_t._M_insert_range_unique(__first, __last); }
+
+      /**
+       *  @brief  %Set copy constructor.
+       *
+       *  Whether the allocator is copied depends on the allocator traits.
+       */
+#if __cplusplus < 201103L
+      set(const set& __x)
+      : _M_t(__x._M_t) { }
+#else
+      set(const set&) = default;
+
+     /**
+       *  @brief %Set move constructor
+       *
+       *  The newly-created %set contains the exact contents of the moved
+       *  instance. The moved instance is a valid, but unspecified, %set.
+       */
+      set(set&&) = default;
+
+      /**
+       *  @brief  Builds a %set from an initializer_list.
+       *  @param  __l  An initializer_list.
+       *  @param  __comp  A comparison functor.
+       *  @param  __a  An allocator object.
+       *
+       *  Create a %set consisting of copies of the elements in the list.
+       *  This is linear in N if the list is already sorted, and NlogN
+       *  otherwise (where N is @a __l.size()).
+       */
+      set(initializer_list<value_type> __l,
+	  const _Compare& __comp = _Compare(),
+	  const allocator_type& __a = allocator_type())
+      : _M_t(__comp, _Key_alloc_type(__a))
+      { _M_t._M_insert_range_unique(__l.begin(), __l.end()); }
+
+      /// Allocator-extended default constructor.
+      explicit
+      set(const allocator_type& __a)
+      : _M_t(_Key_alloc_type(__a)) { }
+
+      /// Allocator-extended copy constructor.
+      set(const set& __x, const __type_identity_t<allocator_type>& __a)
+      : _M_t(__x._M_t, _Key_alloc_type(__a)) { }
+
+      /// Allocator-extended move constructor.
+      set(set&& __x, const __type_identity_t<allocator_type>& __a)
+      noexcept(is_nothrow_copy_constructible<_Compare>::value
+	       && _Alloc_traits::_S_always_equal())
+      : _M_t(std::move(__x._M_t), _Key_alloc_type(__a)) { }
+
+      /// Allocator-extended initialier-list constructor.
+      set(initializer_list<value_type> __l, const allocator_type& __a)
+      : _M_t(_Key_alloc_type(__a))
+      { _M_t._M_insert_range_unique(__l.begin(), __l.end()); }
+
+      /// Allocator-extended range constructor.
+      template<typename _InputIterator>
+	set(_InputIterator __first, _InputIterator __last,
+	    const allocator_type& __a)
+	: _M_t(_Key_alloc_type(__a))
+	{ _M_t._M_insert_range_unique(__first, __last); }
+
+      /**
+       *  The dtor only erases the elements, and note that if the elements
+       *  themselves are pointers, the pointed-to memory is not touched in any
+       *  way. Managing the pointer is the user's responsibility.
+       */
+      ~set() = default;
+#endif
+
+      /**
+       *  @brief  %Set assignment operator.
+       *
+       *  Whether the allocator is copied depends on the allocator traits.
+       */
+#if __cplusplus < 201103L
+      set&
+      operator=(const set& __x)
+      {
+	_M_t = __x._M_t;
+	return *this;
+      }
+#else
+      set&
+      operator=(const set&) = default;
+
+      /// Move assignment operator.
+      set&
+      operator=(set&&) = default;
+
+      /**
+       *  @brief  %Set list assignment operator.
+       *  @param  __l  An initializer_list.
+       *
+       *  This function fills a %set with copies of the elements in the
+       *  initializer list @a __l.
+       *
+       *  Note that the assignment completely changes the %set and
+       *  that the resulting %set's size is the same as the number
+       *  of elements assigned.
+       */
+      set&
+      operator=(initializer_list<value_type> __l)
+      {
+	_M_t._M_assign_unique(__l.begin(), __l.end());
+	return *this;
+      }
+#endif
+
+      // accessors:
+
+      ///  Returns the comparison object with which the %set was constructed.
+      key_compare
+      key_comp() const
+      { return _M_t.key_comp(); }
+      ///  Returns the comparison object with which the %set was constructed.
+      value_compare
+      value_comp() const
+      { return _M_t.key_comp(); }
+      ///  Returns the allocator object with which the %set was constructed.
+      allocator_type
+      get_allocator() const _GLIBCXX_NOEXCEPT
+      { return allocator_type(_M_t.get_allocator()); }
+
+      /**
+       *  Returns a read-only (constant) iterator that points to the first
+       *  element in the %set.  Iteration is done in ascending order according
+       *  to the keys.
+       */
+      iterator
+      begin() const _GLIBCXX_NOEXCEPT
+      { return _M_t.begin(); }
+
+      /**
+       *  Returns a read-only (constant) iterator that points one past the last
+       *  element in the %set.  Iteration is done in ascending order according
+       *  to the keys.
+       */
+      iterator
+      end() const _GLIBCXX_NOEXCEPT
+      { return _M_t.end(); }
+
+      /**
+       *  Returns a read-only (constant) iterator that points to the last
+       *  element in the %set.  Iteration is done in descending order according
+       *  to the keys.
+       */
+      reverse_iterator
+      rbegin() const _GLIBCXX_NOEXCEPT
+      { return _M_t.rbegin(); }
+
+      /**
+       *  Returns a read-only (constant) reverse iterator that points to the
+       *  last pair in the %set.  Iteration is done in descending order
+       *  according to the keys.
+       */
+      reverse_iterator
+      rend() const _GLIBCXX_NOEXCEPT
+      { return _M_t.rend(); }
+
+#if __cplusplus >= 201103L
+      /**
+       *  Returns a read-only (constant) iterator that points to the first
+       *  element in the %set.  Iteration is done in ascending order according
+       *  to the keys.
+       */
+      iterator
+      cbegin() const noexcept
+      { return _M_t.begin(); }
+
+      /**
+       *  Returns a read-only (constant) iterator that points one past the last
+       *  element in the %set.  Iteration is done in ascending order according
+       *  to the keys.
+       */
+      iterator
+      cend() const noexcept
+      { return _M_t.end(); }
+
+      /**
+       *  Returns a read-only (constant) iterator that points to the last
+       *  element in the %set.  Iteration is done in descending order according
+       *  to the keys.
+       */
+      reverse_iterator
+      crbegin() const noexcept
+      { return _M_t.rbegin(); }
+
+      /**
+       *  Returns a read-only (constant) reverse iterator that points to the
+       *  last pair in the %set.  Iteration is done in descending order
+       *  according to the keys.
+       */
+      reverse_iterator
+      crend() const noexcept
+      { return _M_t.rend(); }
+#endif
+
+      ///  Returns true if the %set is empty.
+      _GLIBCXX_NODISCARD bool
+      empty() const _GLIBCXX_NOEXCEPT
+      { return _M_t.empty(); }
+
+      ///  Returns the size of the %set.
+      size_type
+      size() const _GLIBCXX_NOEXCEPT
+      { return _M_t.size(); }
+
+      ///  Returns the maximum size of the %set.
+      size_type
+      max_size() const _GLIBCXX_NOEXCEPT
+      { return _M_t.max_size(); }
+
+      /**
+       *  @brief  Swaps data with another %set.
+       *  @param  __x  A %set of the same element and allocator types.
+       *
+       *  This exchanges the elements between two sets in constant
+       *  time.  (It is only swapping a pointer, an integer, and an
+       *  instance of the @c Compare type (which itself is often
+       *  stateless and empty), so it should be quite fast.)  Note
+       *  that the global std::swap() function is specialized such
+       *  that std::swap(s1,s2) will feed to this function.
+       *
+       *  Whether the allocators are swapped depends on the allocator traits.
+       */
+      void
+      swap(set& __x)
+      _GLIBCXX_NOEXCEPT_IF(__is_nothrow_swappable<_Compare>::value)
+      { _M_t.swap(__x._M_t); }
+
+      // insert/erase
+#if __cplusplus >= 201103L
+      /**
+       *  @brief Attempts to build and insert an element into the %set.
+       *  @param __args  Arguments used to generate an element.
+       *  @return  A pair, of which the first element is an iterator that points
+       *           to the possibly inserted element, and the second is a bool
+       *           that is true if the element was actually inserted.
+       *
+       *  This function attempts to build and insert an element into the %set.
+       *  A %set relies on unique keys and thus an element is only inserted if
+       *  it is not already present in the %set.
+       *
+       *  Insertion requires logarithmic time.
+       */
+      template<typename... _Args>
+	std::pair<iterator, bool>
+	emplace(_Args&&... __args)
+	{ return _M_t._M_emplace_unique(std::forward<_Args>(__args)...); }
+
+      /**
+       *  @brief Attempts to insert an element into the %set.
+       *  @param  __pos  An iterator that serves as a hint as to where the
+       *                element should be inserted.
+       *  @param  __args  Arguments used to generate the element to be
+       *                 inserted.
+       *  @return An iterator that points to the element with key equivalent to
+       *          the one generated from @a __args (may or may not be the
+       *          element itself).
+       *
+       *  This function is not concerned about whether the insertion took place,
+       *  and thus does not return a boolean like the single-argument emplace()
+       *  does.  Note that the first parameter is only a hint and can
+       *  potentially improve the performance of the insertion process.  A bad
+       *  hint would cause no gains in efficiency.
+       *
+       *  For more on @a hinting, see:
+       *  https://gcc.gnu.org/onlinedocs/libstdc++/manual/associative.html#containers.associative.insert_hints
+       *
+       *  Insertion requires logarithmic time (if the hint is not taken).
+       */
+      template<typename... _Args>
+	iterator
+	emplace_hint(const_iterator __pos, _Args&&... __args)
+	{
+	  return _M_t._M_emplace_hint_unique(__pos,
+					     std::forward<_Args>(__args)...);
+	}
+#endif
+
+      /**
+       *  @brief Attempts to insert an element into the %set.
+       *  @param  __x  Element to be inserted.
+       *  @return  A pair, of which the first element is an iterator that points
+       *           to the possibly inserted element, and the second is a bool
+       *           that is true if the element was actually inserted.
+       *
+       *  This function attempts to insert an element into the %set.  A %set
+       *  relies on unique keys and thus an element is only inserted if it is
+       *  not already present in the %set.
+       *
+       *  Insertion requires logarithmic time.
+       */
+      std::pair<iterator, bool>
+      insert(const value_type& __x)
+      {
+	std::pair<typename _Rep_type::iterator, bool> __p =
+	  _M_t._M_insert_unique(__x);
+	return std::pair<iterator, bool>(__p.first, __p.second);
+      }
+
+#if __cplusplus >= 201103L
+      std::pair<iterator, bool>
+      insert(value_type&& __x)
+      {
+	std::pair<typename _Rep_type::iterator, bool> __p =
+	  _M_t._M_insert_unique(std::move(__x));
+	return std::pair<iterator, bool>(__p.first, __p.second);
+      }
+#endif
+
+      /**
+       *  @brief Attempts to insert an element into the %set.
+       *  @param  __position  An iterator that serves as a hint as to where the
+       *                    element should be inserted.
+       *  @param  __x  Element to be inserted.
+       *  @return An iterator that points to the element with key of
+       *           @a __x (may or may not be the element passed in).
+       *
+       *  This function is not concerned about whether the insertion took place,
+       *  and thus does not return a boolean like the single-argument insert()
+       *  does.  Note that the first parameter is only a hint and can
+       *  potentially improve the performance of the insertion process.  A bad
+       *  hint would cause no gains in efficiency.
+       *
+       *  For more on @a hinting, see:
+       *  https://gcc.gnu.org/onlinedocs/libstdc++/manual/associative.html#containers.associative.insert_hints
+       *
+       *  Insertion requires logarithmic time (if the hint is not taken).
+       */
+      iterator
+      insert(const_iterator __position, const value_type& __x)
+      { return _M_t._M_insert_unique_(__position, __x); }
+
+#if __cplusplus >= 201103L
+      iterator
+      insert(const_iterator __position, value_type&& __x)
+      { return _M_t._M_insert_unique_(__position, std::move(__x)); }
+#endif
+
+      /**
+       *  @brief A template function that attempts to insert a range
+       *  of elements.
+       *  @param  __first  Iterator pointing to the start of the range to be
+       *                   inserted.
+       *  @param  __last  Iterator pointing to the end of the range.
+       *
+       *  Complexity similar to that of the range constructor.
+       */
+      template<typename _InputIterator>
+	void
+	insert(_InputIterator __first, _InputIterator __last)
+	{ _M_t._M_insert_range_unique(__first, __last); }
+
+#if __cplusplus >= 201103L
+      /**
+       *  @brief Attempts to insert a list of elements into the %set.
+       *  @param  __l  A std::initializer_list<value_type> of elements
+       *               to be inserted.
+       *
+       *  Complexity similar to that of the range constructor.
+       */
+      void
+      insert(initializer_list<value_type> __l)
+      { this->insert(__l.begin(), __l.end()); }
+#endif
+
+#if __cplusplus > 201402L
+      /// Extract a node.
+      node_type
+      extract(const_iterator __pos)
+      {
+	__glibcxx_assert(__pos != end());
+	return _M_t.extract(__pos);
+      }
+
+      /// Extract a node.
+      node_type
+      extract(const key_type& __x)
+      { return _M_t.extract(__x); }
+
+      /// Re-insert an extracted node.
+      insert_return_type
+      insert(node_type&& __nh)
+      { return _M_t._M_reinsert_node_unique(std::move(__nh)); }
+
+      /// Re-insert an extracted node.
+      iterator
+      insert(const_iterator __hint, node_type&& __nh)
+      { return _M_t._M_reinsert_node_hint_unique(__hint, std::move(__nh)); }
+
+      template<typename, typename>
+	friend struct std::_Rb_tree_merge_helper;
+
+      template<typename _Compare1>
+	void
+	merge(set<_Key, _Compare1, _Alloc>& __source)
+	{
+	  using _Merge_helper = _Rb_tree_merge_helper<set, _Compare1>;
+	  _M_t._M_merge_unique(_Merge_helper::_S_get_tree(__source));
+	}
+
+      template<typename _Compare1>
+	void
+	merge(set<_Key, _Compare1, _Alloc>&& __source)
+	{ merge(__source); }
+
+      template<typename _Compare1>
+	void
+	merge(multiset<_Key, _Compare1, _Alloc>& __source)
+	{
+	  using _Merge_helper = _Rb_tree_merge_helper<set, _Compare1>;
+	  _M_t._M_merge_unique(_Merge_helper::_S_get_tree(__source));
+	}
+
+      template<typename _Compare1>
+	void
+	merge(multiset<_Key, _Compare1, _Alloc>&& __source)
+	{ merge(__source); }
+#endif // C++17
+
+#if __cplusplus >= 201103L
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // DR 130. Associative erase should return an iterator.
+      /**
+       *  @brief Erases an element from a %set.
+       *  @param  __position  An iterator pointing to the element to be erased.
+       *  @return An iterator pointing to the element immediately following
+       *          @a __position prior to the element being erased. If no such
+       *          element exists, end() is returned.
+       *
+       *  This function erases an element, pointed to by the given iterator,
+       *  from a %set.  Note that this function only erases the element, and
+       *  that if the element is itself a pointer, the pointed-to memory is not
+       *  touched in any way.  Managing the pointer is the user's
+       *  responsibility.
+       */
+      _GLIBCXX_ABI_TAG_CXX11
+      iterator
+      erase(const_iterator __position)
+      { return _M_t.erase(__position); }
+#else
+      /**
+       *  @brief Erases an element from a %set.
+       *  @param  position  An iterator pointing to the element to be erased.
+       *
+       *  This function erases an element, pointed to by the given iterator,
+       *  from a %set.  Note that this function only erases the element, and
+       *  that if the element is itself a pointer, the pointed-to memory is not
+       *  touched in any way.  Managing the pointer is the user's
+       *  responsibility.
+       */
+      void
+      erase(iterator __position)
+      { _M_t.erase(__position); }
+#endif
+
+      /**
+       *  @brief Erases elements according to the provided key.
+       *  @param  __x  Key of element to be erased.
+       *  @return  The number of elements erased.
+       *
+       *  This function erases all the elements located by the given key from
+       *  a %set.
+       *  Note that this function only erases the element, and that if
+       *  the element is itself a pointer, the pointed-to memory is not touched
+       *  in any way.  Managing the pointer is the user's responsibility.
+       */
+      size_type
+      erase(const key_type& __x)
+      { return _M_t.erase(__x); }
+
+#if __cplusplus >= 201103L
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // DR 130. Associative erase should return an iterator.
+      /**
+       *  @brief Erases a [__first,__last) range of elements from a %set.
+       *  @param  __first  Iterator pointing to the start of the range to be
+       *                 erased.
+
+       *  @param __last Iterator pointing to the end of the range to
+       *  be erased.
+       *  @return The iterator @a __last.
+       *
+       *  This function erases a sequence of elements from a %set.
+       *  Note that this function only erases the element, and that if
+       *  the element is itself a pointer, the pointed-to memory is not touched
+       *  in any way.  Managing the pointer is the user's responsibility.
+       */
+      _GLIBCXX_ABI_TAG_CXX11
+      iterator
+      erase(const_iterator __first, const_iterator __last)
+      { return _M_t.erase(__first, __last); }
+#else
+      /**
+       *  @brief Erases a [first,last) range of elements from a %set.
+       *  @param  __first  Iterator pointing to the start of the range to be
+       *                 erased.
+       *  @param __last Iterator pointing to the end of the range to
+       *  be erased.
+       *
+       *  This function erases a sequence of elements from a %set.
+       *  Note that this function only erases the element, and that if
+       *  the element is itself a pointer, the pointed-to memory is not touched
+       *  in any way.  Managing the pointer is the user's responsibility.
+       */
+      void
+      erase(iterator __first, iterator __last)
+      { _M_t.erase(__first, __last); }
+#endif
+
+      /**
+       *  Erases all elements in a %set.  Note that this function only erases
+       *  the elements, and that if the elements themselves are pointers, the
+       *  pointed-to memory is not touched in any way.  Managing the pointer is
+       *  the user's responsibility.
+       */
+      void
+      clear() _GLIBCXX_NOEXCEPT
+      { _M_t.clear(); }
+
+      // set operations:
+
+      ///@{
+      /**
+       *  @brief  Finds the number of elements.
+       *  @param  __x  Element to located.
+       *  @return  Number of elements with specified key.
+       *
+       *  This function only makes sense for multisets; for set the result will
+       *  either be 0 (not present) or 1 (present).
+       */
+      size_type
+      count(const key_type& __x) const
+      { return _M_t.find(__x) == _M_t.end() ? 0 : 1; }
+
+#if __cplusplus > 201103L
+      template<typename _Kt>
+	auto
+	count(const _Kt& __x) const
+	-> decltype(_M_t._M_count_tr(__x))
+	{ return _M_t._M_count_tr(__x); }
+#endif
+      ///@}
+
+#if __cplusplus > 201703L
+      ///@{
+      /**
+       *  @brief  Finds whether an element with the given key exists.
+       *  @param  __x  Key of elements to be located.
+       *  @return  True if there is an element with the specified key.
+       */
+      bool
+      contains(const key_type& __x) const
+      { return _M_t.find(__x) != _M_t.end(); }
+
+      template<typename _Kt>
+	auto
+	contains(const _Kt& __x) const
+	-> decltype(_M_t._M_find_tr(__x), void(), true)
+	{ return _M_t._M_find_tr(__x) != _M_t.end(); }
+      ///@}
+#endif
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 214.  set::find() missing const overload
+      ///@{
+      /**
+       *  @brief Tries to locate an element in a %set.
+       *  @param  __x  Element to be located.
+       *  @return  Iterator pointing to sought-after element, or end() if not
+       *           found.
+       *
+       *  This function takes a key and tries to locate the element with which
+       *  the key matches.  If successful the function returns an iterator
+       *  pointing to the sought after element.  If unsuccessful it returns the
+       *  past-the-end ( @c end() ) iterator.
+       */
+      iterator
+      find(const key_type& __x)
+      { return _M_t.find(__x); }
+
+      const_iterator
+      find(const key_type& __x) const
+      { return _M_t.find(__x); }
+
+#if __cplusplus > 201103L
+      template<typename _Kt>
+	auto
+	find(const _Kt& __x)
+	-> decltype(iterator{_M_t._M_find_tr(__x)})
+	{ return iterator{_M_t._M_find_tr(__x)}; }
+
+      template<typename _Kt>
+	auto
+	find(const _Kt& __x) const
+	-> decltype(const_iterator{_M_t._M_find_tr(__x)})
+	{ return const_iterator{_M_t._M_find_tr(__x)}; }
+#endif
+      ///@}
+
+      ///@{
+      /**
+       *  @brief Finds the beginning of a subsequence matching given key.
+       *  @param  __x  Key to be located.
+       *  @return  Iterator pointing to first element equal to or greater
+       *           than key, or end().
+       *
+       *  This function returns the first element of a subsequence of elements
+       *  that matches the given key.  If unsuccessful it returns an iterator
+       *  pointing to the first element that has a greater value than given key
+       *  or end() if no such element exists.
+       */
+      iterator
+      lower_bound(const key_type& __x)
+      { return _M_t.lower_bound(__x); }
+
+      const_iterator
+      lower_bound(const key_type& __x) const
+      { return _M_t.lower_bound(__x); }
+
+#if __cplusplus > 201103L
+      template<typename _Kt>
+	auto
+	lower_bound(const _Kt& __x)
+	-> decltype(iterator(_M_t._M_lower_bound_tr(__x)))
+	{ return iterator(_M_t._M_lower_bound_tr(__x)); }
+
+      template<typename _Kt>
+	auto
+	lower_bound(const _Kt& __x) const
+	-> decltype(const_iterator(_M_t._M_lower_bound_tr(__x)))
+	{ return const_iterator(_M_t._M_lower_bound_tr(__x)); }
+#endif
+      ///@}
+
+      ///@{
+      /**
+       *  @brief Finds the end of a subsequence matching given key.
+       *  @param  __x  Key to be located.
+       *  @return Iterator pointing to the first element
+       *          greater than key, or end().
+       */
+      iterator
+      upper_bound(const key_type& __x)
+      { return _M_t.upper_bound(__x); }
+
+      const_iterator
+      upper_bound(const key_type& __x) const
+      { return _M_t.upper_bound(__x); }
+
+#if __cplusplus > 201103L
+      template<typename _Kt>
+	auto
+	upper_bound(const _Kt& __x)
+	-> decltype(iterator(_M_t._M_upper_bound_tr(__x)))
+	{ return iterator(_M_t._M_upper_bound_tr(__x)); }
+
+      template<typename _Kt>
+	auto
+	upper_bound(const _Kt& __x) const
+	-> decltype(iterator(_M_t._M_upper_bound_tr(__x)))
+	{ return const_iterator(_M_t._M_upper_bound_tr(__x)); }
+#endif
+      ///@}
+
+      ///@{
+      /**
+       *  @brief Finds a subsequence matching given key.
+       *  @param  __x  Key to be located.
+       *  @return  Pair of iterators that possibly points to the subsequence
+       *           matching given key.
+       *
+       *  This function is equivalent to
+       *  @code
+       *    std::make_pair(c.lower_bound(val),
+       *                   c.upper_bound(val))
+       *  @endcode
+       *  (but is faster than making the calls separately).
+       *
+       *  This function probably only makes sense for multisets.
+       */
+      std::pair<iterator, iterator>
+      equal_range(const key_type& __x)
+      { return _M_t.equal_range(__x); }
+
+      std::pair<const_iterator, const_iterator>
+      equal_range(const key_type& __x) const
+      { return _M_t.equal_range(__x); }
+
+#if __cplusplus > 201103L
+      template<typename _Kt>
+	auto
+	equal_range(const _Kt& __x)
+	-> decltype(pair<iterator, iterator>(_M_t._M_equal_range_tr(__x)))
+	{ return pair<iterator, iterator>(_M_t._M_equal_range_tr(__x)); }
+
+      template<typename _Kt>
+	auto
+	equal_range(const _Kt& __x) const
+	-> decltype(pair<iterator, iterator>(_M_t._M_equal_range_tr(__x)))
+	{ return pair<iterator, iterator>(_M_t._M_equal_range_tr(__x)); }
+#endif
+      ///@}
+
+      template<typename _K1, typename _C1, typename _A1>
+	friend bool
+	operator==(const set<_K1, _C1, _A1>&, const set<_K1, _C1, _A1>&);
+
+#if __cpp_lib_three_way_comparison
+      template<typename _K1, typename _C1, typename _A1>
+	friend __detail::__synth3way_t<_K1>
+	operator<=>(const set<_K1, _C1, _A1>&, const set<_K1, _C1, _A1>&);
+#else
+      template<typename _K1, typename _C1, typename _A1>
+	friend bool
+	operator<(const set<_K1, _C1, _A1>&, const set<_K1, _C1, _A1>&);
+#endif
+    };
+
+#if __cpp_deduction_guides >= 201606
+
+  template<typename _InputIterator,
+	   typename _Compare =
+	     less<typename iterator_traits<_InputIterator>::value_type>,
+	   typename _Allocator =
+	     allocator<typename iterator_traits<_InputIterator>::value_type>,
+	   typename = _RequireInputIter<_InputIterator>,
+	   typename = _RequireNotAllocator<_Compare>,
+	   typename = _RequireAllocator<_Allocator>>
+    set(_InputIterator, _InputIterator,
+	_Compare = _Compare(), _Allocator = _Allocator())
+    -> set<typename iterator_traits<_InputIterator>::value_type,
+	  _Compare, _Allocator>;
+
+  template<typename _Key, typename _Compare = less<_Key>,
+	   typename _Allocator = allocator<_Key>,
+	   typename = _RequireNotAllocator<_Compare>,
+	   typename = _RequireAllocator<_Allocator>>
+    set(initializer_list<_Key>,
+	_Compare = _Compare(), _Allocator = _Allocator())
+    -> set<_Key, _Compare, _Allocator>;
+
+  template<typename _InputIterator, typename _Allocator,
+	   typename = _RequireInputIter<_InputIterator>,
+	   typename = _RequireAllocator<_Allocator>>
+    set(_InputIterator, _InputIterator, _Allocator)
+    -> set<typename iterator_traits<_InputIterator>::value_type,
+	   less<typename iterator_traits<_InputIterator>::value_type>,
+	   _Allocator>;
+
+  template<typename _Key, typename _Allocator,
+	   typename = _RequireAllocator<_Allocator>>
+    set(initializer_list<_Key>, _Allocator)
+    -> set<_Key, less<_Key>, _Allocator>;
+
+#endif // deduction guides
+
+  /**
+   *  @brief  Set equality comparison.
+   *  @param  __x  A %set.
+   *  @param  __y  A %set of the same type as @a x.
+   *  @return  True iff the size and elements of the sets are equal.
+   *
+   *  This is an equivalence relation.  It is linear in the size of the sets.
+   *  Sets are considered equivalent if their sizes are equal, and if
+   *  corresponding elements compare equal.
+  */
+  template<typename _Key, typename _Compare, typename _Alloc>
+    inline bool
+    operator==(const set<_Key, _Compare, _Alloc>& __x,
+	       const set<_Key, _Compare, _Alloc>& __y)
+    { return __x._M_t == __y._M_t; }
+
+#if __cpp_lib_three_way_comparison
+  /**
+   *  @brief  Set ordering relation.
+   *  @param  __x  A `set`.
+   *  @param  __y  A `set` of the same type as `x`.
+   *  @return  A value indicating whether `__x` is less than, equal to,
+   *           greater than, or incomparable with `__y`.
+   *
+   *  This is a total ordering relation.  It is linear in the size of the
+   *  maps.  The elements must be comparable with @c <.
+   *
+   *  See `std::lexicographical_compare_three_way()` for how the determination
+   *  is made. This operator is used to synthesize relational operators like
+   *  `<` and `>=` etc.
+  */
+  template<typename _Key, typename _Compare, typename _Alloc>
+    inline __detail::__synth3way_t<_Key>
+    operator<=>(const set<_Key, _Compare, _Alloc>& __x,
+		const set<_Key, _Compare, _Alloc>& __y)
+    { return __x._M_t <=> __y._M_t; }
+#else
+  /**
+   *  @brief  Set ordering relation.
+   *  @param  __x  A %set.
+   *  @param  __y  A %set of the same type as @a x.
+   *  @return  True iff @a __x is lexicographically less than @a __y.
+   *
+   *  This is a total ordering relation.  It is linear in the size of the
+   *  sets.  The elements must be comparable with @c <.
+   *
+   *  See std::lexicographical_compare() for how the determination is made.
+  */
+  template<typename _Key, typename _Compare, typename _Alloc>
+    inline bool
+    operator<(const set<_Key, _Compare, _Alloc>& __x,
+	      const set<_Key, _Compare, _Alloc>& __y)
+    { return __x._M_t < __y._M_t; }
+
+  ///  Returns !(x == y).
+  template<typename _Key, typename _Compare, typename _Alloc>
+    inline bool
+    operator!=(const set<_Key, _Compare, _Alloc>& __x,
+	       const set<_Key, _Compare, _Alloc>& __y)
+    { return !(__x == __y); }
+
+  ///  Returns y < x.
+  template<typename _Key, typename _Compare, typename _Alloc>
+    inline bool
+    operator>(const set<_Key, _Compare, _Alloc>& __x,
+	      const set<_Key, _Compare, _Alloc>& __y)
+    { return __y < __x; }
+
+  ///  Returns !(y < x)
+  template<typename _Key, typename _Compare, typename _Alloc>
+    inline bool
+    operator<=(const set<_Key, _Compare, _Alloc>& __x,
+	       const set<_Key, _Compare, _Alloc>& __y)
+    { return !(__y < __x); }
+
+  ///  Returns !(x < y)
+  template<typename _Key, typename _Compare, typename _Alloc>
+    inline bool
+    operator>=(const set<_Key, _Compare, _Alloc>& __x,
+	       const set<_Key, _Compare, _Alloc>& __y)
+    { return !(__x < __y); }
+#endif // three-way comparison
+
+  /// See std::set::swap().
+  template<typename _Key, typename _Compare, typename _Alloc>
+    inline void
+    swap(set<_Key, _Compare, _Alloc>& __x, set<_Key, _Compare, _Alloc>& __y)
+    _GLIBCXX_NOEXCEPT_IF(noexcept(__x.swap(__y)))
+    { __x.swap(__y); }
+
+_GLIBCXX_END_NAMESPACE_CONTAINER
+
+#if __cplusplus > 201402L
+  // Allow std::set access to internals of compatible sets.
+  template<typename _Val, typename _Cmp1, typename _Alloc, typename _Cmp2>
+    struct
+    _Rb_tree_merge_helper<_GLIBCXX_STD_C::set<_Val, _Cmp1, _Alloc>, _Cmp2>
+    {
+    private:
+      friend class _GLIBCXX_STD_C::set<_Val, _Cmp1, _Alloc>;
+
+      static auto&
+      _S_get_tree(_GLIBCXX_STD_C::set<_Val, _Cmp2, _Alloc>& __set)
+      { return __set._M_t; }
+
+      static auto&
+      _S_get_tree(_GLIBCXX_STD_C::multiset<_Val, _Cmp2, _Alloc>& __set)
+      { return __set._M_t; }
+    };
+#endif // C++17
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} //namespace std
+#endif /* _STL_SET_H */
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stl_stack.h
@@ -0,0 +1,435 @@
+// Stack implementation -*- C++ -*-
+
+// Copyright (C) 2001-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/*
+ *
+ * Copyright (c) 1994
+ * Hewlett-Packard Company
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Hewlett-Packard Company makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ *
+ *
+ * Copyright (c) 1996,1997
+ * Silicon Graphics Computer Systems, Inc.
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Silicon Graphics makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ */
+
+/** @file bits/stl_stack.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{stack}
+ */
+
+#ifndef _STL_STACK_H
+#define _STL_STACK_H 1
+
+#include <bits/concept_check.h>
+#include <debug/debug.h>
+#if __cplusplus >= 201103L
+# include <bits/uses_allocator.h>
+#endif
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /**
+   *  @brief  A standard container giving FILO behavior.
+   *
+   *  @ingroup sequences
+   *
+   *  @tparam _Tp  Type of element.
+   *  @tparam _Sequence  Type of underlying sequence, defaults to deque<_Tp>.
+   *
+   *  Meets many of the requirements of a
+   *  <a href="tables.html#65">container</a>,
+   *  but does not define anything to do with iterators.  Very few of the
+   *  other standard container interfaces are defined.
+   *
+   *  This is not a true container, but an @e adaptor.  It holds
+   *  another container, and provides a wrapper interface to that
+   *  container.  The wrapper is what enforces strict
+   *  first-in-last-out %stack behavior.
+   *
+   *  The second template parameter defines the type of the underlying
+   *  sequence/container.  It defaults to std::deque, but it can be
+   *  any type that supports @c back, @c push_back, and @c pop_back,
+   *  such as std::list, std::vector, or an appropriate user-defined
+   *  type.
+   *
+   *  Members not found in @a normal containers are @c container_type,
+   *  which is a typedef for the second Sequence parameter, and @c
+   *  push, @c pop, and @c top, which are standard %stack/FILO
+   *  operations.
+  */
+  template<typename _Tp, typename _Sequence = deque<_Tp> >
+    class stack
+    {
+#ifdef _GLIBCXX_CONCEPT_CHECKS
+      // concept requirements
+      typedef typename _Sequence::value_type _Sequence_value_type;
+# if __cplusplus < 201103L
+      __glibcxx_class_requires(_Tp, _SGIAssignableConcept)
+      __glibcxx_class_requires(_Sequence, _BackInsertionSequenceConcept)
+# endif
+      __glibcxx_class_requires2(_Tp, _Sequence_value_type, _SameTypeConcept)
+#endif
+
+      template<typename _Tp1, typename _Seq1>
+	friend bool
+	operator==(const stack<_Tp1, _Seq1>&, const stack<_Tp1, _Seq1>&);
+
+      template<typename _Tp1, typename _Seq1>
+	friend bool
+	operator<(const stack<_Tp1, _Seq1>&, const stack<_Tp1, _Seq1>&);
+
+#if __cpp_lib_three_way_comparison
+      template<typename _Tp1, three_way_comparable _Seq1>
+	friend compare_three_way_result_t<_Seq1>
+	operator<=>(const stack<_Tp1, _Seq1>&, const stack<_Tp1, _Seq1>&);
+#endif
+
+#if __cplusplus >= 201103L
+      template<typename _Alloc>
+	using _Uses = typename
+	  enable_if<uses_allocator<_Sequence, _Alloc>::value>::type;
+
+#if __cplusplus >= 201703L
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 2566. Requirements on the first template parameter of container
+      // adaptors
+      static_assert(is_same<_Tp, typename _Sequence::value_type>::value,
+	  "value_type must be the same as the underlying container");
+#endif // C++17
+#endif // C++11
+
+    public:
+      typedef typename _Sequence::value_type		value_type;
+      typedef typename _Sequence::reference		reference;
+      typedef typename _Sequence::const_reference	const_reference;
+      typedef typename _Sequence::size_type		size_type;
+      typedef	       _Sequence			container_type;
+
+    protected:
+      //  See queue::c for notes on this name.
+      _Sequence c;
+
+    public:
+      // XXX removed old def ctor, added def arg to this one to match 14882
+      /**
+       *  @brief  Default constructor creates no elements.
+       */
+#if __cplusplus < 201103L
+      explicit
+      stack(const _Sequence& __c = _Sequence())
+      : c(__c) { }
+#else
+      template<typename _Seq = _Sequence, typename _Requires = typename
+	       enable_if<is_default_constructible<_Seq>::value>::type>
+	stack()
+	: c() { }
+
+      explicit
+      stack(const _Sequence& __c)
+      : c(__c) { }
+
+      explicit
+      stack(_Sequence&& __c)
+      : c(std::move(__c)) { }
+
+#if __cplusplus > 202002L
+#define __cpp_lib_adaptor_iterator_pair_constructor 202106L
+
+      template<typename _InputIterator,
+	       typename = _RequireInputIter<_InputIterator>>
+	stack(_InputIterator __first, _InputIterator __last)
+	: c(__first, __last) { }
+#endif
+
+
+      template<typename _Alloc, typename _Requires = _Uses<_Alloc>>
+	explicit
+	stack(const _Alloc& __a)
+	: c(__a) { }
+
+      template<typename _Alloc, typename _Requires = _Uses<_Alloc>>
+	stack(const _Sequence& __c, const _Alloc& __a)
+	: c(__c, __a) { }
+
+      template<typename _Alloc, typename _Requires = _Uses<_Alloc>>
+	stack(_Sequence&& __c, const _Alloc& __a)
+	: c(std::move(__c), __a) { }
+
+      template<typename _Alloc, typename _Requires = _Uses<_Alloc>>
+	stack(const stack& __q, const _Alloc& __a)
+	: c(__q.c, __a) { }
+
+      template<typename _Alloc, typename _Requires = _Uses<_Alloc>>
+	stack(stack&& __q, const _Alloc& __a)
+	: c(std::move(__q.c), __a) { }
+
+#if __cplusplus > 202002L
+      template<typename _InputIterator, typename _Alloc,
+	       typename = _RequireInputIter<_InputIterator>,
+	       typename = _Uses<_Alloc>>
+	stack(_InputIterator __first, _InputIterator __last, const _Alloc& __a)
+	: c(__first, __last, __a) { }
+#endif
+#endif
+
+      /**
+       *  Returns true if the %stack is empty.
+       */
+      _GLIBCXX_NODISCARD bool
+      empty() const
+      { return c.empty(); }
+
+      /**  Returns the number of elements in the %stack.  */
+      _GLIBCXX_NODISCARD
+      size_type
+      size() const
+      { return c.size(); }
+
+      /**
+       *  Returns a read/write reference to the data at the first
+       *  element of the %stack.
+       */
+      _GLIBCXX_NODISCARD
+      reference
+      top()
+      {
+	__glibcxx_requires_nonempty();
+	return c.back();
+      }
+
+      /**
+       *  Returns a read-only (constant) reference to the data at the first
+       *  element of the %stack.
+       */
+      _GLIBCXX_NODISCARD
+      const_reference
+      top() const
+      {
+	__glibcxx_requires_nonempty();
+	return c.back();
+      }
+
+      /**
+       *  @brief  Add data to the top of the %stack.
+       *  @param  __x  Data to be added.
+       *
+       *  This is a typical %stack operation.  The function creates an
+       *  element at the top of the %stack and assigns the given data
+       *  to it.  The time complexity of the operation depends on the
+       *  underlying sequence.
+       */
+      void
+      push(const value_type& __x)
+      { c.push_back(__x); }
+
+#if __cplusplus >= 201103L
+      void
+      push(value_type&& __x)
+      { c.push_back(std::move(__x)); }
+
+#if __cplusplus > 201402L
+      template<typename... _Args>
+	decltype(auto)
+	emplace(_Args&&... __args)
+	{ return c.emplace_back(std::forward<_Args>(__args)...); }
+#else
+      template<typename... _Args>
+	void
+	emplace(_Args&&... __args)
+	{ c.emplace_back(std::forward<_Args>(__args)...); }
+#endif
+#endif
+
+      /**
+       *  @brief  Removes first element.
+       *
+       *  This is a typical %stack operation.  It shrinks the %stack
+       *  by one.  The time complexity of the operation depends on the
+       *  underlying sequence.
+       *
+       *  Note that no data is returned, and if the first element's
+       *  data is needed, it should be retrieved before pop() is
+       *  called.
+       */
+      void
+      pop()
+      {
+	__glibcxx_requires_nonempty();
+	c.pop_back();
+      }
+
+#if __cplusplus >= 201103L
+      void
+      swap(stack& __s)
+#if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11
+      noexcept(__is_nothrow_swappable<_Sequence>::value)
+#else
+      noexcept(__is_nothrow_swappable<_Tp>::value)
+#endif
+      {
+	using std::swap;
+	swap(c, __s.c);
+      }
+#endif // __cplusplus >= 201103L
+    };
+
+#if __cpp_deduction_guides >= 201606
+  template<typename _Container,
+	   typename = _RequireNotAllocator<_Container>>
+    stack(_Container) -> stack<typename _Container::value_type, _Container>;
+
+  template<typename _Container, typename _Allocator,
+	   typename = _RequireNotAllocator<_Container>>
+    stack(_Container, _Allocator)
+    -> stack<typename _Container::value_type, _Container>;
+
+#ifdef __cpp_lib_adaptor_iterator_pair_constructor
+  template<typename _InputIterator,
+	   typename _ValT
+	     = typename iterator_traits<_InputIterator>::value_type,
+	   typename = _RequireInputIter<_InputIterator>>
+    stack(_InputIterator, _InputIterator) -> stack<_ValT>;
+
+  template<typename _InputIterator, typename _Allocator,
+	   typename _ValT
+	     = typename iterator_traits<_InputIterator>::value_type,
+	   typename = _RequireInputIter<_InputIterator>,
+	   typename = _RequireAllocator<_Allocator>>
+    stack(_InputIterator, _InputIterator, _Allocator)
+    -> stack<_ValT, deque<_ValT, _Allocator>>;
+#endif
+#endif
+
+  /**
+   *  @brief  Stack equality comparison.
+   *  @param  __x  A %stack.
+   *  @param  __y  A %stack of the same type as @a __x.
+   *  @return  True iff the size and elements of the stacks are equal.
+   *
+   *  This is an equivalence relation.  Complexity and semantics
+   *  depend on the underlying sequence type, but the expected rules
+   *  are: this relation is linear in the size of the sequences, and
+   *  stacks are considered equivalent if their sequences compare
+   *  equal.
+  */
+  template<typename _Tp, typename _Seq>
+    _GLIBCXX_NODISCARD
+    inline bool
+    operator==(const stack<_Tp, _Seq>& __x, const stack<_Tp, _Seq>& __y)
+    { return __x.c == __y.c; }
+
+  /**
+   *  @brief  Stack ordering relation.
+   *  @param  __x  A %stack.
+   *  @param  __y  A %stack of the same type as @a x.
+   *  @return  True iff @a x is lexicographically less than @a __y.
+   *
+   *  This is an total ordering relation.  Complexity and semantics
+   *  depend on the underlying sequence type, but the expected rules
+   *  are: this relation is linear in the size of the sequences, the
+   *  elements must be comparable with @c <, and
+   *  std::lexicographical_compare() is usually used to make the
+   *  determination.
+  */
+  template<typename _Tp, typename _Seq>
+    _GLIBCXX_NODISCARD
+    inline bool
+    operator<(const stack<_Tp, _Seq>& __x, const stack<_Tp, _Seq>& __y)
+    { return __x.c < __y.c; }
+
+  /// Based on operator==
+  template<typename _Tp, typename _Seq>
+    _GLIBCXX_NODISCARD
+    inline bool
+    operator!=(const stack<_Tp, _Seq>& __x, const stack<_Tp, _Seq>& __y)
+    { return !(__x == __y); }
+
+  /// Based on operator<
+  template<typename _Tp, typename _Seq>
+    _GLIBCXX_NODISCARD
+    inline bool
+    operator>(const stack<_Tp, _Seq>& __x, const stack<_Tp, _Seq>& __y)
+    { return __y < __x; }
+
+  /// Based on operator<
+  template<typename _Tp, typename _Seq>
+    _GLIBCXX_NODISCARD
+    inline bool
+    operator<=(const stack<_Tp, _Seq>& __x, const stack<_Tp, _Seq>& __y)
+    { return !(__y < __x); }
+
+  /// Based on operator<
+  template<typename _Tp, typename _Seq>
+    _GLIBCXX_NODISCARD
+    inline bool
+    operator>=(const stack<_Tp, _Seq>& __x, const stack<_Tp, _Seq>& __y)
+    { return !(__x < __y); }
+
+#if __cpp_lib_three_way_comparison
+  template<typename _Tp, three_way_comparable _Seq>
+    [[nodiscard]]
+    inline compare_three_way_result_t<_Seq>
+    operator<=>(const stack<_Tp, _Seq>& __x, const stack<_Tp, _Seq>& __y)
+    { return __x.c <=> __y.c; }
+#endif
+
+#if __cplusplus >= 201103L
+  template<typename _Tp, typename _Seq>
+    inline
+#if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11
+    // Constrained free swap overload, see p0185r1
+    typename enable_if<__is_swappable<_Seq>::value>::type
+#else
+    void
+#endif
+    swap(stack<_Tp, _Seq>& __x, stack<_Tp, _Seq>& __y)
+    noexcept(noexcept(__x.swap(__y)))
+    { __x.swap(__y); }
+
+  template<typename _Tp, typename _Seq, typename _Alloc>
+    struct uses_allocator<stack<_Tp, _Seq>, _Alloc>
+    : public uses_allocator<_Seq, _Alloc>::type { };
+#endif // __cplusplus >= 201103L
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif /* _STL_STACK_H */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stl_stack.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stl_stack.h.blob
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@@ -0,0 +1,285 @@
+// Temporary buffer implementation -*- C++ -*-
+
+// Copyright (C) 2001-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/*
+ *
+ * Copyright (c) 1994
+ * Hewlett-Packard Company
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Hewlett-Packard Company makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ *
+ *
+ * Copyright (c) 1996,1997
+ * Silicon Graphics Computer Systems, Inc.
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Silicon Graphics makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ */
+
+/** @file bits/stl_tempbuf.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{memory}
+ */
+
+#ifndef _STL_TEMPBUF_H
+#define _STL_TEMPBUF_H 1
+
+#include <bits/stl_algobase.h>
+#include <bits/stl_construct.h>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  namespace __detail
+  {
+    template<typename _Tp>
+      inline void
+      __return_temporary_buffer(_Tp* __p,
+				size_t __len __attribute__((__unused__)))
+      {
+#if __cpp_sized_deallocation
+	::operator delete(__p, __len * sizeof(_Tp));
+#else
+	::operator delete(__p);
+#endif
+      }
+  }
+
+  /**
+   *  @brief Allocates a temporary buffer.
+   *  @param  __len  The number of objects of type Tp.
+   *  @return See full description.
+   *
+   *  Reinventing the wheel, but this time with prettier spokes!
+   *
+   *  This function tries to obtain storage for @c __len adjacent Tp
+   *  objects.  The objects themselves are not constructed, of course.
+   *  A pair<> is returned containing <em>the buffer s address and
+   *  capacity (in the units of sizeof(_Tp)), or a pair of 0 values if
+   *  no storage can be obtained.</em>  Note that the capacity obtained
+   *  may be less than that requested if the memory is unavailable;
+   *  you should compare len with the .second return value.
+   *
+   * Provides the nothrow exception guarantee.
+   */
+  template<typename _Tp>
+    _GLIBCXX17_DEPRECATED
+    pair<_Tp*, ptrdiff_t>
+    get_temporary_buffer(ptrdiff_t __len) _GLIBCXX_NOEXCEPT
+    {
+      const ptrdiff_t __max =
+	__gnu_cxx::__numeric_traits<ptrdiff_t>::__max / sizeof(_Tp);
+      if (__len > __max)
+	__len = __max;
+
+      while (__len > 0)
+	{
+	  _Tp* __tmp = static_cast<_Tp*>(::operator new(__len * sizeof(_Tp),
+							std::nothrow));
+	  if (__tmp != 0)
+	    return std::pair<_Tp*, ptrdiff_t>(__tmp, __len);
+	  __len = __len == 1 ? 0 : ((__len + 1) / 2);
+	}
+      return std::pair<_Tp*, ptrdiff_t>(static_cast<_Tp*>(0), 0);
+    }
+
+  /**
+   *  @brief The companion to get_temporary_buffer().
+   *  @param  __p  A buffer previously allocated by get_temporary_buffer.
+   *  @return   None.
+   *
+   *  Frees the memory pointed to by __p.
+   */
+  template<typename _Tp>
+    inline void
+    return_temporary_buffer(_Tp* __p)
+    { ::operator delete(__p); }
+
+  /**
+   *  This class is used in two places: stl_algo.h and ext/memory,
+   *  where it is wrapped as the temporary_buffer class.  See
+   *  temporary_buffer docs for more notes.
+   */
+  template<typename _ForwardIterator, typename _Tp>
+    class _Temporary_buffer
+    {
+      // concept requirements
+      __glibcxx_class_requires(_ForwardIterator, _ForwardIteratorConcept)
+
+    public:
+      typedef _Tp         value_type;
+      typedef value_type* pointer;
+      typedef pointer     iterator;
+      typedef ptrdiff_t   size_type;
+
+    protected:
+      size_type  _M_original_len;
+      size_type  _M_len;
+      pointer    _M_buffer;
+
+    public:
+      /// As per Table mumble.
+      size_type
+      size() const
+      { return _M_len; }
+
+      /// Returns the size requested by the constructor; may be >size().
+      size_type
+      requested_size() const
+      { return _M_original_len; }
+
+      /// As per Table mumble.
+      iterator
+      begin()
+      { return _M_buffer; }
+
+      /// As per Table mumble.
+      iterator
+      end()
+      { return _M_buffer + _M_len; }
+
+      /**
+       * Constructs a temporary buffer of a size somewhere between
+       * zero and the given length.
+       */
+      _Temporary_buffer(_ForwardIterator __seed, size_type __original_len);
+
+      ~_Temporary_buffer()
+      {
+	std::_Destroy(_M_buffer, _M_buffer + _M_len);
+	std::__detail::__return_temporary_buffer(_M_buffer, _M_len);
+      }
+
+    private:
+      // Disable copy constructor and assignment operator.
+      _Temporary_buffer(const _Temporary_buffer&);
+
+      void
+      operator=(const _Temporary_buffer&);
+    };
+
+
+  template<bool>
+    struct __uninitialized_construct_buf_dispatch
+    {
+      template<typename _Pointer, typename _ForwardIterator>
+        static void
+        __ucr(_Pointer __first, _Pointer __last,
+	      _ForwardIterator __seed)
+        {
+	  if (__first == __last)
+	    return;
+
+	  _Pointer __cur = __first;
+	  __try
+	    {
+	      std::_Construct(std::__addressof(*__first),
+			      _GLIBCXX_MOVE(*__seed));
+	      _Pointer __prev = __cur;
+	      ++__cur;
+	      for(; __cur != __last; ++__cur, ++__prev)
+		std::_Construct(std::__addressof(*__cur),
+				_GLIBCXX_MOVE(*__prev));
+	      *__seed = _GLIBCXX_MOVE(*__prev);
+	    }
+	  __catch(...)
+	    {
+	      std::_Destroy(__first, __cur);
+	      __throw_exception_again;
+	    }
+	}
+    };
+
+  template<>
+    struct __uninitialized_construct_buf_dispatch<true>
+    {
+      template<typename _Pointer, typename _ForwardIterator>
+        static void
+        __ucr(_Pointer, _Pointer, _ForwardIterator) { }
+    };
+
+  // Constructs objects in the range [first, last).
+  // Note that while these new objects will take valid values,
+  // their exact value is not defined. In particular they may
+  // be 'moved from'.
+  //
+  // While *__seed may be altered during this algorithm, it will have
+  // the same value when the algorithm finishes, unless one of the
+  // constructions throws.
+  //
+  // Requirements: _Pointer::value_type(_Tp&&) is valid.
+  template<typename _Pointer, typename _ForwardIterator>
+    inline void
+    __uninitialized_construct_buf(_Pointer __first, _Pointer __last,
+				  _ForwardIterator __seed)
+    {
+      typedef typename std::iterator_traits<_Pointer>::value_type
+	_ValueType;
+
+      std::__uninitialized_construct_buf_dispatch<
+        __has_trivial_constructor(_ValueType)>::
+	  __ucr(__first, __last, __seed);
+    }
+
+  template<typename _ForwardIterator, typename _Tp>
+    _Temporary_buffer<_ForwardIterator, _Tp>::
+    _Temporary_buffer(_ForwardIterator __seed, size_type __original_len)
+    : _M_original_len(__original_len), _M_len(0), _M_buffer(0)
+    {
+      std::pair<pointer, size_type> __p(
+		std::get_temporary_buffer<value_type>(_M_original_len));
+
+      if (__p.first)
+	{
+	  __try
+	    {
+	      std::__uninitialized_construct_buf(__p.first, __p.first + __p.second,
+						 __seed);
+	      _M_buffer = __p.first;
+	      _M_len = __p.second;
+	    }
+	  __catch(...)
+	    {
+	      std::__detail::__return_temporary_buffer(__p.first, __p.second);
+	      __throw_exception_again;
+	    }
+	}
+    }
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif /* _STL_TEMPBUF_H */
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stl_tree.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stl_tree.h
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stl_tree.h
@@ -0,0 +1,2622 @@
+// RB tree implementation -*- C++ -*-
+
+// Copyright (C) 2001-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/*
+ *
+ * Copyright (c) 1996,1997
+ * Silicon Graphics Computer Systems, Inc.
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Silicon Graphics makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ *
+ *
+ * Copyright (c) 1994
+ * Hewlett-Packard Company
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Hewlett-Packard Company makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ *
+ *
+ */
+
+/** @file bits/stl_tree.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{map,set}
+ */
+
+#ifndef _STL_TREE_H
+#define _STL_TREE_H 1
+
+#pragma GCC system_header
+
+#include <bits/stl_algobase.h>
+#include <bits/allocator.h>
+#include <bits/stl_function.h>
+#include <bits/cpp_type_traits.h>
+#include <ext/alloc_traits.h>
+#if __cplusplus >= 201103L
+# include <ext/aligned_buffer.h>
+#endif
+#if __cplusplus > 201402L
+# include <bits/node_handle.h>
+#endif
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+#if __cplusplus > 201103L
+# define __cpp_lib_generic_associative_lookup 201304L
+#endif
+
+  // Red-black tree class, designed for use in implementing STL
+  // associative containers (set, multiset, map, and multimap). The
+  // insertion and deletion algorithms are based on those in Cormen,
+  // Leiserson, and Rivest, Introduction to Algorithms (MIT Press,
+  // 1990), except that
+  //
+  // (1) the header cell is maintained with links not only to the root
+  // but also to the leftmost node of the tree, to enable constant
+  // time begin(), and to the rightmost node of the tree, to enable
+  // linear time performance when used with the generic set algorithms
+  // (set_union, etc.)
+  //
+  // (2) when a node being deleted has two children its successor node
+  // is relinked into its place, rather than copied, so that the only
+  // iterators invalidated are those referring to the deleted node.
+
+  enum _Rb_tree_color { _S_red = false, _S_black = true };
+
+  struct _Rb_tree_node_base
+  {
+    typedef _Rb_tree_node_base* _Base_ptr;
+    typedef const _Rb_tree_node_base* _Const_Base_ptr;
+
+    _Rb_tree_color	_M_color;
+    _Base_ptr		_M_parent;
+    _Base_ptr		_M_left;
+    _Base_ptr		_M_right;
+
+    static _Base_ptr
+    _S_minimum(_Base_ptr __x) _GLIBCXX_NOEXCEPT
+    {
+      while (__x->_M_left != 0) __x = __x->_M_left;
+      return __x;
+    }
+
+    static _Const_Base_ptr
+    _S_minimum(_Const_Base_ptr __x) _GLIBCXX_NOEXCEPT
+    {
+      while (__x->_M_left != 0) __x = __x->_M_left;
+      return __x;
+    }
+
+    static _Base_ptr
+    _S_maximum(_Base_ptr __x) _GLIBCXX_NOEXCEPT
+    {
+      while (__x->_M_right != 0) __x = __x->_M_right;
+      return __x;
+    }
+
+    static _Const_Base_ptr
+    _S_maximum(_Const_Base_ptr __x) _GLIBCXX_NOEXCEPT
+    {
+      while (__x->_M_right != 0) __x = __x->_M_right;
+      return __x;
+    }
+  };
+
+  // Helper type offering value initialization guarantee on the compare functor.
+  template<typename _Key_compare>
+    struct _Rb_tree_key_compare
+    {
+      _Key_compare		_M_key_compare;
+
+      _Rb_tree_key_compare()
+      _GLIBCXX_NOEXCEPT_IF(
+	is_nothrow_default_constructible<_Key_compare>::value)
+      : _M_key_compare()
+      { }
+
+      _Rb_tree_key_compare(const _Key_compare& __comp)
+      : _M_key_compare(__comp)
+      { }
+
+#if __cplusplus >= 201103L
+      // Copy constructor added for consistency with C++98 mode.
+      _Rb_tree_key_compare(const _Rb_tree_key_compare&) = default;
+
+      _Rb_tree_key_compare(_Rb_tree_key_compare&& __x)
+	noexcept(is_nothrow_copy_constructible<_Key_compare>::value)
+      : _M_key_compare(__x._M_key_compare)
+      { }
+#endif
+    };
+
+  // Helper type to manage default initialization of node count and header.
+  struct _Rb_tree_header
+  {
+    _Rb_tree_node_base	_M_header;
+    size_t		_M_node_count; // Keeps track of size of tree.
+
+    _Rb_tree_header() _GLIBCXX_NOEXCEPT
+    {
+      _M_header._M_color = _S_red;
+      _M_reset();
+    }
+
+#if __cplusplus >= 201103L
+    _Rb_tree_header(_Rb_tree_header&& __x) noexcept
+    {
+      if (__x._M_header._M_parent != nullptr)
+	_M_move_data(__x);
+      else
+	{
+	  _M_header._M_color = _S_red;
+	  _M_reset();
+	}
+    }
+#endif
+
+    void
+    _M_move_data(_Rb_tree_header& __from)
+    {
+      _M_header._M_color = __from._M_header._M_color;
+      _M_header._M_parent = __from._M_header._M_parent;
+      _M_header._M_left = __from._M_header._M_left;
+      _M_header._M_right = __from._M_header._M_right;
+      _M_header._M_parent->_M_parent = &_M_header;
+      _M_node_count = __from._M_node_count;
+
+      __from._M_reset();
+    }
+
+    void
+    _M_reset()
+    {
+      _M_header._M_parent = 0;
+      _M_header._M_left = &_M_header;
+      _M_header._M_right = &_M_header;
+      _M_node_count = 0;
+    }
+  };
+
+  template<typename _Val>
+    struct _Rb_tree_node : public _Rb_tree_node_base
+    {
+      typedef _Rb_tree_node<_Val>* _Link_type;
+
+#if __cplusplus < 201103L
+      _Val _M_value_field;
+
+      _Val*
+      _M_valptr()
+      { return std::__addressof(_M_value_field); }
+
+      const _Val*
+      _M_valptr() const
+      { return std::__addressof(_M_value_field); }
+#else
+      __gnu_cxx::__aligned_membuf<_Val> _M_storage;
+
+      _Val*
+      _M_valptr()
+      { return _M_storage._M_ptr(); }
+
+      const _Val*
+      _M_valptr() const
+      { return _M_storage._M_ptr(); }
+#endif
+    };
+
+  _GLIBCXX_PURE _Rb_tree_node_base*
+  _Rb_tree_increment(_Rb_tree_node_base* __x) throw ();
+
+  _GLIBCXX_PURE const _Rb_tree_node_base*
+  _Rb_tree_increment(const _Rb_tree_node_base* __x) throw ();
+
+  _GLIBCXX_PURE _Rb_tree_node_base*
+  _Rb_tree_decrement(_Rb_tree_node_base* __x) throw ();
+
+  _GLIBCXX_PURE const _Rb_tree_node_base*
+  _Rb_tree_decrement(const _Rb_tree_node_base* __x) throw ();
+
+  template<typename _Tp>
+    struct _Rb_tree_iterator
+    {
+      typedef _Tp  value_type;
+      typedef _Tp& reference;
+      typedef _Tp* pointer;
+
+      typedef bidirectional_iterator_tag iterator_category;
+      typedef ptrdiff_t			 difference_type;
+
+      typedef _Rb_tree_iterator<_Tp>		_Self;
+      typedef _Rb_tree_node_base::_Base_ptr	_Base_ptr;
+      typedef _Rb_tree_node<_Tp>*		_Link_type;
+
+      _Rb_tree_iterator() _GLIBCXX_NOEXCEPT
+      : _M_node() { }
+
+      explicit
+      _Rb_tree_iterator(_Base_ptr __x) _GLIBCXX_NOEXCEPT
+      : _M_node(__x) { }
+
+      reference
+      operator*() const _GLIBCXX_NOEXCEPT
+      { return *static_cast<_Link_type>(_M_node)->_M_valptr(); }
+
+      pointer
+      operator->() const _GLIBCXX_NOEXCEPT
+      { return static_cast<_Link_type> (_M_node)->_M_valptr(); }
+
+      _Self&
+      operator++() _GLIBCXX_NOEXCEPT
+      {
+	_M_node = _Rb_tree_increment(_M_node);
+	return *this;
+      }
+
+      _Self
+      operator++(int) _GLIBCXX_NOEXCEPT
+      {
+	_Self __tmp = *this;
+	_M_node = _Rb_tree_increment(_M_node);
+	return __tmp;
+      }
+
+      _Self&
+      operator--() _GLIBCXX_NOEXCEPT
+      {
+	_M_node = _Rb_tree_decrement(_M_node);
+	return *this;
+      }
+
+      _Self
+      operator--(int) _GLIBCXX_NOEXCEPT
+      {
+	_Self __tmp = *this;
+	_M_node = _Rb_tree_decrement(_M_node);
+	return __tmp;
+      }
+
+      friend bool
+      operator==(const _Self& __x, const _Self& __y) _GLIBCXX_NOEXCEPT
+      { return __x._M_node == __y._M_node; }
+
+#if ! __cpp_lib_three_way_comparison
+      friend bool
+      operator!=(const _Self& __x, const _Self& __y) _GLIBCXX_NOEXCEPT
+      { return __x._M_node != __y._M_node; }
+#endif
+
+      _Base_ptr _M_node;
+    };
+
+  template<typename _Tp>
+    struct _Rb_tree_const_iterator
+    {
+      typedef _Tp	 value_type;
+      typedef const _Tp& reference;
+      typedef const _Tp* pointer;
+
+      typedef _Rb_tree_iterator<_Tp> iterator;
+
+      typedef bidirectional_iterator_tag iterator_category;
+      typedef ptrdiff_t			 difference_type;
+
+      typedef _Rb_tree_const_iterator<_Tp>		_Self;
+      typedef _Rb_tree_node_base::_Const_Base_ptr	_Base_ptr;
+      typedef const _Rb_tree_node<_Tp>*			_Link_type;
+
+      _Rb_tree_const_iterator() _GLIBCXX_NOEXCEPT
+      : _M_node() { }
+
+      explicit
+      _Rb_tree_const_iterator(_Base_ptr __x) _GLIBCXX_NOEXCEPT
+      : _M_node(__x) { }
+
+      _Rb_tree_const_iterator(const iterator& __it) _GLIBCXX_NOEXCEPT
+      : _M_node(__it._M_node) { }
+
+      iterator
+      _M_const_cast() const _GLIBCXX_NOEXCEPT
+      { return iterator(const_cast<typename iterator::_Base_ptr>(_M_node)); }
+
+      reference
+      operator*() const _GLIBCXX_NOEXCEPT
+      { return *static_cast<_Link_type>(_M_node)->_M_valptr(); }
+
+      pointer
+      operator->() const _GLIBCXX_NOEXCEPT
+      { return static_cast<_Link_type>(_M_node)->_M_valptr(); }
+
+      _Self&
+      operator++() _GLIBCXX_NOEXCEPT
+      {
+	_M_node = _Rb_tree_increment(_M_node);
+	return *this;
+      }
+
+      _Self
+      operator++(int) _GLIBCXX_NOEXCEPT
+      {
+	_Self __tmp = *this;
+	_M_node = _Rb_tree_increment(_M_node);
+	return __tmp;
+      }
+
+      _Self&
+      operator--() _GLIBCXX_NOEXCEPT
+      {
+	_M_node = _Rb_tree_decrement(_M_node);
+	return *this;
+      }
+
+      _Self
+      operator--(int) _GLIBCXX_NOEXCEPT
+      {
+	_Self __tmp = *this;
+	_M_node = _Rb_tree_decrement(_M_node);
+	return __tmp;
+      }
+
+      friend bool
+      operator==(const _Self& __x, const _Self& __y) _GLIBCXX_NOEXCEPT
+      { return __x._M_node == __y._M_node; }
+
+#if ! __cpp_lib_three_way_comparison
+      friend bool
+      operator!=(const _Self& __x, const _Self& __y) _GLIBCXX_NOEXCEPT
+      { return __x._M_node != __y._M_node; }
+#endif
+
+      _Base_ptr _M_node;
+    };
+
+  void
+  _Rb_tree_insert_and_rebalance(const bool __insert_left,
+				_Rb_tree_node_base* __x,
+				_Rb_tree_node_base* __p,
+				_Rb_tree_node_base& __header) throw ();
+
+  _Rb_tree_node_base*
+  _Rb_tree_rebalance_for_erase(_Rb_tree_node_base* const __z,
+			       _Rb_tree_node_base& __header) throw ();
+
+#if __cplusplus > 201402L
+  template<typename _Tree1, typename _Cmp2>
+    struct _Rb_tree_merge_helper { };
+#endif
+
+  template<typename _Key, typename _Val, typename _KeyOfValue,
+	   typename _Compare, typename _Alloc = allocator<_Val> >
+    class _Rb_tree
+    {
+      typedef typename __gnu_cxx::__alloc_traits<_Alloc>::template
+	rebind<_Rb_tree_node<_Val> >::other _Node_allocator;
+
+      typedef __gnu_cxx::__alloc_traits<_Node_allocator> _Alloc_traits;
+
+    protected:
+      typedef _Rb_tree_node_base* 		_Base_ptr;
+      typedef const _Rb_tree_node_base* 	_Const_Base_ptr;
+      typedef _Rb_tree_node<_Val>* 		_Link_type;
+      typedef const _Rb_tree_node<_Val>*	_Const_Link_type;
+
+    private:
+      // Functor recycling a pool of nodes and using allocation once the pool
+      // is empty.
+      struct _Reuse_or_alloc_node
+      {
+	_Reuse_or_alloc_node(_Rb_tree& __t)
+	: _M_root(__t._M_root()), _M_nodes(__t._M_rightmost()), _M_t(__t)
+	{
+	  if (_M_root)
+	    {
+	      _M_root->_M_parent = 0;
+
+	      if (_M_nodes->_M_left)
+		_M_nodes = _M_nodes->_M_left;
+	    }
+	  else
+	    _M_nodes = 0;
+	}
+
+#if __cplusplus >= 201103L
+	_Reuse_or_alloc_node(const _Reuse_or_alloc_node&) = delete;
+#endif
+
+	~_Reuse_or_alloc_node()
+	{ _M_t._M_erase(static_cast<_Link_type>(_M_root)); }
+
+	template<typename _Arg>
+	  _Link_type
+	  operator()(_GLIBCXX_FWDREF(_Arg) __arg)
+	  {
+	    _Link_type __node = static_cast<_Link_type>(_M_extract());
+	    if (__node)
+	      {
+		_M_t._M_destroy_node(__node);
+		_M_t._M_construct_node(__node, _GLIBCXX_FORWARD(_Arg, __arg));
+		return __node;
+	      }
+
+	    return _M_t._M_create_node(_GLIBCXX_FORWARD(_Arg, __arg));
+	  }
+
+      private:
+	_Base_ptr
+	_M_extract()
+	{
+	  if (!_M_nodes)
+	    return _M_nodes;
+
+	  _Base_ptr __node = _M_nodes;
+	  _M_nodes = _M_nodes->_M_parent;
+	  if (_M_nodes)
+	    {
+	      if (_M_nodes->_M_right == __node)
+		{
+		  _M_nodes->_M_right = 0;
+
+		  if (_M_nodes->_M_left)
+		    {
+		      _M_nodes = _M_nodes->_M_left;
+
+		      while (_M_nodes->_M_right)
+			_M_nodes = _M_nodes->_M_right;
+
+		      if (_M_nodes->_M_left)
+			_M_nodes = _M_nodes->_M_left;
+		    }
+		}
+	      else // __node is on the left.
+		_M_nodes->_M_left = 0;
+	    }
+	  else
+	    _M_root = 0;
+
+	  return __node;
+	}
+
+	_Base_ptr _M_root;
+	_Base_ptr _M_nodes;
+	_Rb_tree& _M_t;
+      };
+
+      // Functor similar to the previous one but without any pool of nodes to
+      // recycle.
+      struct _Alloc_node
+      {
+	_Alloc_node(_Rb_tree& __t)
+	: _M_t(__t) { }
+
+	template<typename _Arg>
+	  _Link_type
+	  operator()(_GLIBCXX_FWDREF(_Arg) __arg) const
+	  { return _M_t._M_create_node(_GLIBCXX_FORWARD(_Arg, __arg)); }
+
+      private:
+	_Rb_tree& _M_t;
+      };
+
+    public:
+      typedef _Key 				key_type;
+      typedef _Val 				value_type;
+      typedef value_type* 			pointer;
+      typedef const value_type* 		const_pointer;
+      typedef value_type& 			reference;
+      typedef const value_type& 		const_reference;
+      typedef size_t 				size_type;
+      typedef ptrdiff_t 			difference_type;
+      typedef _Alloc 				allocator_type;
+
+      _Node_allocator&
+      _M_get_Node_allocator() _GLIBCXX_NOEXCEPT
+      { return this->_M_impl; }
+
+      const _Node_allocator&
+      _M_get_Node_allocator() const _GLIBCXX_NOEXCEPT
+      { return this->_M_impl; }
+
+      allocator_type
+      get_allocator() const _GLIBCXX_NOEXCEPT
+      { return allocator_type(_M_get_Node_allocator()); }
+
+    protected:
+      _Link_type
+      _M_get_node()
+      { return _Alloc_traits::allocate(_M_get_Node_allocator(), 1); }
+
+      void
+      _M_put_node(_Link_type __p) _GLIBCXX_NOEXCEPT
+      { _Alloc_traits::deallocate(_M_get_Node_allocator(), __p, 1); }
+
+#if __cplusplus < 201103L
+      void
+      _M_construct_node(_Link_type __node, const value_type& __x)
+      {
+	__try
+	  { get_allocator().construct(__node->_M_valptr(), __x); }
+	__catch(...)
+	  {
+	    _M_put_node(__node);
+	    __throw_exception_again;
+	  }
+      }
+
+      _Link_type
+      _M_create_node(const value_type& __x)
+      {
+	_Link_type __tmp = _M_get_node();
+	_M_construct_node(__tmp, __x);
+	return __tmp;
+      }
+#else
+      template<typename... _Args>
+	void
+	_M_construct_node(_Link_type __node, _Args&&... __args)
+	{
+	  __try
+	    {
+	      ::new(__node) _Rb_tree_node<_Val>;
+	      _Alloc_traits::construct(_M_get_Node_allocator(),
+				       __node->_M_valptr(),
+				       std::forward<_Args>(__args)...);
+	    }
+	  __catch(...)
+	    {
+	      __node->~_Rb_tree_node<_Val>();
+	      _M_put_node(__node);
+	      __throw_exception_again;
+	    }
+	}
+
+      template<typename... _Args>
+	_Link_type
+	_M_create_node(_Args&&... __args)
+	{
+	  _Link_type __tmp = _M_get_node();
+	  _M_construct_node(__tmp, std::forward<_Args>(__args)...);
+	  return __tmp;
+	}
+#endif
+
+      void
+      _M_destroy_node(_Link_type __p) _GLIBCXX_NOEXCEPT
+      {
+#if __cplusplus < 201103L
+	get_allocator().destroy(__p->_M_valptr());
+#else
+	_Alloc_traits::destroy(_M_get_Node_allocator(), __p->_M_valptr());
+	__p->~_Rb_tree_node<_Val>();
+#endif
+      }
+
+      void
+      _M_drop_node(_Link_type __p) _GLIBCXX_NOEXCEPT
+      {
+	_M_destroy_node(__p);
+	_M_put_node(__p);
+      }
+
+      template<bool _MoveValue, typename _NodeGen>
+	_Link_type
+	_M_clone_node(_Link_type __x, _NodeGen& __node_gen)
+	{
+#if __cplusplus >= 201103L
+	  using _Vp = __conditional_t<_MoveValue,
+				      value_type&&,
+				      const value_type&>;
+#endif
+	  _Link_type __tmp
+	    = __node_gen(_GLIBCXX_FORWARD(_Vp, *__x->_M_valptr()));
+	  __tmp->_M_color = __x->_M_color;
+	  __tmp->_M_left = 0;
+	  __tmp->_M_right = 0;
+	  return __tmp;
+	}
+
+    protected:
+#if _GLIBCXX_INLINE_VERSION
+      template<typename _Key_compare>
+#else
+      // Unused _Is_pod_comparator is kept as it is part of mangled name.
+      template<typename _Key_compare,
+	       bool /* _Is_pod_comparator */ = __is_pod(_Key_compare)>
+#endif
+	struct _Rb_tree_impl
+	: public _Node_allocator
+	, public _Rb_tree_key_compare<_Key_compare>
+	, public _Rb_tree_header
+	{
+	  typedef _Rb_tree_key_compare<_Key_compare> _Base_key_compare;
+
+	  _Rb_tree_impl()
+	    _GLIBCXX_NOEXCEPT_IF(
+		is_nothrow_default_constructible<_Node_allocator>::value
+		&& is_nothrow_default_constructible<_Base_key_compare>::value )
+	  : _Node_allocator()
+	  { }
+
+	  _Rb_tree_impl(const _Rb_tree_impl& __x)
+	  : _Node_allocator(_Alloc_traits::_S_select_on_copy(__x))
+	  , _Base_key_compare(__x._M_key_compare)
+	  , _Rb_tree_header()
+	  { }
+
+#if __cplusplus < 201103L
+	  _Rb_tree_impl(const _Key_compare& __comp, const _Node_allocator& __a)
+	  : _Node_allocator(__a), _Base_key_compare(__comp)
+	  { }
+#else
+	  _Rb_tree_impl(_Rb_tree_impl&&)
+	    noexcept( is_nothrow_move_constructible<_Base_key_compare>::value )
+	  = default;
+
+	  explicit
+	  _Rb_tree_impl(_Node_allocator&& __a)
+	  : _Node_allocator(std::move(__a))
+	  { }
+
+	  _Rb_tree_impl(_Rb_tree_impl&& __x, _Node_allocator&& __a)
+	  : _Node_allocator(std::move(__a)),
+	    _Base_key_compare(std::move(__x)),
+	    _Rb_tree_header(std::move(__x))
+	  { }
+
+	  _Rb_tree_impl(const _Key_compare& __comp, _Node_allocator&& __a)
+	  : _Node_allocator(std::move(__a)), _Base_key_compare(__comp)
+	  { }
+#endif
+	};
+
+      _Rb_tree_impl<_Compare> _M_impl;
+
+    protected:
+      _Base_ptr&
+      _M_root() _GLIBCXX_NOEXCEPT
+      { return this->_M_impl._M_header._M_parent; }
+
+      _Const_Base_ptr
+      _M_root() const _GLIBCXX_NOEXCEPT
+      { return this->_M_impl._M_header._M_parent; }
+
+      _Base_ptr&
+      _M_leftmost() _GLIBCXX_NOEXCEPT
+      { return this->_M_impl._M_header._M_left; }
+
+      _Const_Base_ptr
+      _M_leftmost() const _GLIBCXX_NOEXCEPT
+      { return this->_M_impl._M_header._M_left; }
+
+      _Base_ptr&
+      _M_rightmost() _GLIBCXX_NOEXCEPT
+      { return this->_M_impl._M_header._M_right; }
+
+      _Const_Base_ptr
+      _M_rightmost() const _GLIBCXX_NOEXCEPT
+      { return this->_M_impl._M_header._M_right; }
+
+      _Link_type
+      _M_mbegin() const _GLIBCXX_NOEXCEPT
+      { return static_cast<_Link_type>(this->_M_impl._M_header._M_parent); }
+
+      _Link_type
+      _M_begin() _GLIBCXX_NOEXCEPT
+      { return _M_mbegin(); }
+
+      _Const_Link_type
+      _M_begin() const _GLIBCXX_NOEXCEPT
+      {
+	return static_cast<_Const_Link_type>
+	  (this->_M_impl._M_header._M_parent);
+      }
+
+      _Base_ptr
+      _M_end() _GLIBCXX_NOEXCEPT
+      { return &this->_M_impl._M_header; }
+
+      _Const_Base_ptr
+      _M_end() const _GLIBCXX_NOEXCEPT
+      { return &this->_M_impl._M_header; }
+
+      static const _Key&
+      _S_key(_Const_Link_type __x)
+      {
+#if __cplusplus >= 201103L
+	// If we're asking for the key we're presumably using the comparison
+	// object, and so this is a good place to sanity check it.
+	static_assert(__is_invocable<_Compare&, const _Key&, const _Key&>{},
+		      "comparison object must be invocable "
+		      "with two arguments of key type");
+# if __cplusplus >= 201703L
+	// _GLIBCXX_RESOLVE_LIB_DEFECTS
+	// 2542. Missing const requirements for associative containers
+	if constexpr (__is_invocable<_Compare&, const _Key&, const _Key&>{})
+	  static_assert(
+	      is_invocable_v<const _Compare&, const _Key&, const _Key&>,
+	      "comparison object must be invocable as const");
+# endif // C++17
+#endif // C++11
+
+	return _KeyOfValue()(*__x->_M_valptr());
+      }
+
+      static _Link_type
+      _S_left(_Base_ptr __x) _GLIBCXX_NOEXCEPT
+      { return static_cast<_Link_type>(__x->_M_left); }
+
+      static _Const_Link_type
+      _S_left(_Const_Base_ptr __x) _GLIBCXX_NOEXCEPT
+      { return static_cast<_Const_Link_type>(__x->_M_left); }
+
+      static _Link_type
+      _S_right(_Base_ptr __x) _GLIBCXX_NOEXCEPT
+      { return static_cast<_Link_type>(__x->_M_right); }
+
+      static _Const_Link_type
+      _S_right(_Const_Base_ptr __x) _GLIBCXX_NOEXCEPT
+      { return static_cast<_Const_Link_type>(__x->_M_right); }
+
+      static const _Key&
+      _S_key(_Const_Base_ptr __x)
+      { return _S_key(static_cast<_Const_Link_type>(__x)); }
+
+      static _Base_ptr
+      _S_minimum(_Base_ptr __x) _GLIBCXX_NOEXCEPT
+      { return _Rb_tree_node_base::_S_minimum(__x); }
+
+      static _Const_Base_ptr
+      _S_minimum(_Const_Base_ptr __x) _GLIBCXX_NOEXCEPT
+      { return _Rb_tree_node_base::_S_minimum(__x); }
+
+      static _Base_ptr
+      _S_maximum(_Base_ptr __x) _GLIBCXX_NOEXCEPT
+      { return _Rb_tree_node_base::_S_maximum(__x); }
+
+      static _Const_Base_ptr
+      _S_maximum(_Const_Base_ptr __x) _GLIBCXX_NOEXCEPT
+      { return _Rb_tree_node_base::_S_maximum(__x); }
+
+    public:
+      typedef _Rb_tree_iterator<value_type>       iterator;
+      typedef _Rb_tree_const_iterator<value_type> const_iterator;
+
+      typedef std::reverse_iterator<iterator>       reverse_iterator;
+      typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
+
+#if __cplusplus > 201402L
+      using node_type = _Node_handle<_Key, _Val, _Node_allocator>;
+      using insert_return_type = _Node_insert_return<
+	__conditional_t<is_same_v<_Key, _Val>, const_iterator, iterator>,
+	node_type>;
+#endif
+
+      pair<_Base_ptr, _Base_ptr>
+      _M_get_insert_unique_pos(const key_type& __k);
+
+      pair<_Base_ptr, _Base_ptr>
+      _M_get_insert_equal_pos(const key_type& __k);
+
+      pair<_Base_ptr, _Base_ptr>
+      _M_get_insert_hint_unique_pos(const_iterator __pos,
+				    const key_type& __k);
+
+      pair<_Base_ptr, _Base_ptr>
+      _M_get_insert_hint_equal_pos(const_iterator __pos,
+				   const key_type& __k);
+
+    private:
+#if __cplusplus >= 201103L
+      template<typename _Arg, typename _NodeGen>
+	iterator
+	_M_insert_(_Base_ptr __x, _Base_ptr __y, _Arg&& __v, _NodeGen&);
+
+      iterator
+      _M_insert_node(_Base_ptr __x, _Base_ptr __y, _Link_type __z);
+
+      template<typename _Arg>
+	iterator
+	_M_insert_lower(_Base_ptr __y, _Arg&& __v);
+
+      template<typename _Arg>
+	iterator
+	_M_insert_equal_lower(_Arg&& __x);
+
+      iterator
+      _M_insert_lower_node(_Base_ptr __p, _Link_type __z);
+
+      iterator
+      _M_insert_equal_lower_node(_Link_type __z);
+#else
+      template<typename _NodeGen>
+	iterator
+	_M_insert_(_Base_ptr __x, _Base_ptr __y,
+		   const value_type& __v, _NodeGen&);
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 233. Insertion hints in associative containers.
+      iterator
+      _M_insert_lower(_Base_ptr __y, const value_type& __v);
+
+      iterator
+      _M_insert_equal_lower(const value_type& __x);
+#endif
+
+      enum { __as_lvalue, __as_rvalue };
+
+      template<bool _MoveValues, typename _NodeGen>
+	_Link_type
+	_M_copy(_Link_type, _Base_ptr, _NodeGen&);
+
+      template<bool _MoveValues, typename _NodeGen>
+	_Link_type
+	_M_copy(const _Rb_tree& __x, _NodeGen& __gen)
+	{
+	  _Link_type __root =
+	    _M_copy<_MoveValues>(__x._M_mbegin(), _M_end(), __gen);
+	  _M_leftmost() = _S_minimum(__root);
+	  _M_rightmost() = _S_maximum(__root);
+	  _M_impl._M_node_count = __x._M_impl._M_node_count;
+	  return __root;
+	}
+
+      _Link_type
+      _M_copy(const _Rb_tree& __x)
+      {
+	_Alloc_node __an(*this);
+	return _M_copy<__as_lvalue>(__x, __an);
+      }
+
+      void
+      _M_erase(_Link_type __x);
+
+      iterator
+      _M_lower_bound(_Link_type __x, _Base_ptr __y,
+		     const _Key& __k);
+
+      const_iterator
+      _M_lower_bound(_Const_Link_type __x, _Const_Base_ptr __y,
+		     const _Key& __k) const;
+
+      iterator
+      _M_upper_bound(_Link_type __x, _Base_ptr __y,
+		     const _Key& __k);
+
+      const_iterator
+      _M_upper_bound(_Const_Link_type __x, _Const_Base_ptr __y,
+		     const _Key& __k) const;
+
+    public:
+      // allocation/deallocation
+#if __cplusplus < 201103L
+      _Rb_tree() { }
+#else
+      _Rb_tree() = default;
+#endif
+
+      _Rb_tree(const _Compare& __comp,
+	       const allocator_type& __a = allocator_type())
+      : _M_impl(__comp, _Node_allocator(__a)) { }
+
+      _Rb_tree(const _Rb_tree& __x)
+      : _M_impl(__x._M_impl)
+      {
+	if (__x._M_root() != 0)
+	  _M_root() = _M_copy(__x);
+      }
+
+#if __cplusplus >= 201103L
+      _Rb_tree(const allocator_type& __a)
+      : _M_impl(_Node_allocator(__a))
+      { }
+
+      _Rb_tree(const _Rb_tree& __x, const allocator_type& __a)
+      : _M_impl(__x._M_impl._M_key_compare, _Node_allocator(__a))
+      {
+	if (__x._M_root() != nullptr)
+	  _M_root() = _M_copy(__x);
+      }
+
+      _Rb_tree(_Rb_tree&&) = default;
+
+      _Rb_tree(_Rb_tree&& __x, const allocator_type& __a)
+      : _Rb_tree(std::move(__x), _Node_allocator(__a))
+      { }
+
+    private:
+      _Rb_tree(_Rb_tree&& __x, _Node_allocator&& __a, true_type)
+      noexcept(is_nothrow_default_constructible<_Compare>::value)
+      : _M_impl(std::move(__x._M_impl), std::move(__a))
+      { }
+
+      _Rb_tree(_Rb_tree&& __x, _Node_allocator&& __a, false_type)
+      : _M_impl(__x._M_impl._M_key_compare, std::move(__a))
+      {
+	if (__x._M_root() != nullptr)
+	  _M_move_data(__x, false_type{});
+      }
+
+    public:
+      _Rb_tree(_Rb_tree&& __x, _Node_allocator&& __a)
+      noexcept( noexcept(
+	_Rb_tree(std::declval<_Rb_tree&&>(), std::declval<_Node_allocator&&>(),
+		 std::declval<typename _Alloc_traits::is_always_equal>())) )
+      : _Rb_tree(std::move(__x), std::move(__a),
+		 typename _Alloc_traits::is_always_equal{})
+      { }
+#endif
+
+      ~_Rb_tree() _GLIBCXX_NOEXCEPT
+      { _M_erase(_M_begin()); }
+
+      _Rb_tree&
+      operator=(const _Rb_tree& __x);
+
+      // Accessors.
+      _Compare
+      key_comp() const
+      { return _M_impl._M_key_compare; }
+
+      iterator
+      begin() _GLIBCXX_NOEXCEPT
+      { return iterator(this->_M_impl._M_header._M_left); }
+
+      const_iterator
+      begin() const _GLIBCXX_NOEXCEPT
+      { return const_iterator(this->_M_impl._M_header._M_left); }
+
+      iterator
+      end() _GLIBCXX_NOEXCEPT
+      { return iterator(&this->_M_impl._M_header); }
+
+      const_iterator
+      end() const _GLIBCXX_NOEXCEPT
+      { return const_iterator(&this->_M_impl._M_header); }
+
+      reverse_iterator
+      rbegin() _GLIBCXX_NOEXCEPT
+      { return reverse_iterator(end()); }
+
+      const_reverse_iterator
+      rbegin() const _GLIBCXX_NOEXCEPT
+      { return const_reverse_iterator(end()); }
+
+      reverse_iterator
+      rend() _GLIBCXX_NOEXCEPT
+      { return reverse_iterator(begin()); }
+
+      const_reverse_iterator
+      rend() const _GLIBCXX_NOEXCEPT
+      { return const_reverse_iterator(begin()); }
+
+      _GLIBCXX_NODISCARD bool
+      empty() const _GLIBCXX_NOEXCEPT
+      { return _M_impl._M_node_count == 0; }
+
+      size_type
+      size() const _GLIBCXX_NOEXCEPT
+      { return _M_impl._M_node_count; }
+
+      size_type
+      max_size() const _GLIBCXX_NOEXCEPT
+      { return _Alloc_traits::max_size(_M_get_Node_allocator()); }
+
+      void
+      swap(_Rb_tree& __t)
+      _GLIBCXX_NOEXCEPT_IF(__is_nothrow_swappable<_Compare>::value);
+
+      // Insert/erase.
+#if __cplusplus >= 201103L
+      template<typename _Arg>
+	pair<iterator, bool>
+	_M_insert_unique(_Arg&& __x);
+
+      template<typename _Arg>
+	iterator
+	_M_insert_equal(_Arg&& __x);
+
+      template<typename _Arg, typename _NodeGen>
+	iterator
+	_M_insert_unique_(const_iterator __pos, _Arg&& __x, _NodeGen&);
+
+      template<typename _Arg>
+	iterator
+	_M_insert_unique_(const_iterator __pos, _Arg&& __x)
+	{
+	  _Alloc_node __an(*this);
+	  return _M_insert_unique_(__pos, std::forward<_Arg>(__x), __an);
+	}
+
+      template<typename _Arg, typename _NodeGen>
+	iterator
+	_M_insert_equal_(const_iterator __pos, _Arg&& __x, _NodeGen&);
+
+      template<typename _Arg>
+	iterator
+	_M_insert_equal_(const_iterator __pos, _Arg&& __x)
+	{
+	  _Alloc_node __an(*this);
+	  return _M_insert_equal_(__pos, std::forward<_Arg>(__x), __an);
+	}
+
+      template<typename... _Args>
+	pair<iterator, bool>
+	_M_emplace_unique(_Args&&... __args);
+
+      template<typename... _Args>
+	iterator
+	_M_emplace_equal(_Args&&... __args);
+
+      template<typename... _Args>
+	iterator
+	_M_emplace_hint_unique(const_iterator __pos, _Args&&... __args);
+
+      template<typename... _Args>
+	iterator
+	_M_emplace_hint_equal(const_iterator __pos, _Args&&... __args);
+
+      template<typename _Iter>
+	using __same_value_type
+	  = is_same<value_type, typename iterator_traits<_Iter>::value_type>;
+
+      template<typename _InputIterator>
+	__enable_if_t<__same_value_type<_InputIterator>::value>
+	_M_insert_range_unique(_InputIterator __first, _InputIterator __last)
+	{
+	  _Alloc_node __an(*this);
+	  for (; __first != __last; ++__first)
+	    _M_insert_unique_(end(), *__first, __an);
+	}
+
+      template<typename _InputIterator>
+	__enable_if_t<!__same_value_type<_InputIterator>::value>
+	_M_insert_range_unique(_InputIterator __first, _InputIterator __last)
+	{
+	  for (; __first != __last; ++__first)
+	    _M_emplace_unique(*__first);
+	}
+
+      template<typename _InputIterator>
+	__enable_if_t<__same_value_type<_InputIterator>::value>
+	_M_insert_range_equal(_InputIterator __first, _InputIterator __last)
+	{
+	  _Alloc_node __an(*this);
+	  for (; __first != __last; ++__first)
+	    _M_insert_equal_(end(), *__first, __an);
+	}
+
+      template<typename _InputIterator>
+	__enable_if_t<!__same_value_type<_InputIterator>::value>
+	_M_insert_range_equal(_InputIterator __first, _InputIterator __last)
+	{
+	  _Alloc_node __an(*this);
+	  for (; __first != __last; ++__first)
+	    _M_emplace_equal(*__first);
+	}
+#else
+      pair<iterator, bool>
+      _M_insert_unique(const value_type& __x);
+
+      iterator
+      _M_insert_equal(const value_type& __x);
+
+      template<typename _NodeGen>
+	iterator
+	_M_insert_unique_(const_iterator __pos, const value_type& __x,
+			  _NodeGen&);
+
+      iterator
+      _M_insert_unique_(const_iterator __pos, const value_type& __x)
+      {
+	_Alloc_node __an(*this);
+	return _M_insert_unique_(__pos, __x, __an);
+      }
+
+      template<typename _NodeGen>
+	iterator
+	_M_insert_equal_(const_iterator __pos, const value_type& __x,
+			 _NodeGen&);
+      iterator
+      _M_insert_equal_(const_iterator __pos, const value_type& __x)
+      {
+	_Alloc_node __an(*this);
+	return _M_insert_equal_(__pos, __x, __an);
+      }
+
+      template<typename _InputIterator>
+	void
+	_M_insert_range_unique(_InputIterator __first, _InputIterator __last)
+	{
+	  _Alloc_node __an(*this);
+	  for (; __first != __last; ++__first)
+	    _M_insert_unique_(end(), *__first, __an);
+	}
+
+      template<typename _InputIterator>
+	void
+	_M_insert_range_equal(_InputIterator __first, _InputIterator __last)
+	{
+	  _Alloc_node __an(*this);
+	  for (; __first != __last; ++__first)
+	    _M_insert_equal_(end(), *__first, __an);
+	}
+#endif
+
+    private:
+      void
+      _M_erase_aux(const_iterator __position);
+
+      void
+      _M_erase_aux(const_iterator __first, const_iterator __last);
+
+    public:
+#if __cplusplus >= 201103L
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // DR 130. Associative erase should return an iterator.
+      _GLIBCXX_ABI_TAG_CXX11
+      iterator
+      erase(const_iterator __position)
+      {
+	__glibcxx_assert(__position != end());
+	const_iterator __result = __position;
+	++__result;
+	_M_erase_aux(__position);
+	return __result._M_const_cast();
+      }
+
+      // LWG 2059.
+      _GLIBCXX_ABI_TAG_CXX11
+      iterator
+      erase(iterator __position)
+      {
+	__glibcxx_assert(__position != end());
+	iterator __result = __position;
+	++__result;
+	_M_erase_aux(__position);
+	return __result;
+      }
+#else
+      void
+      erase(iterator __position)
+      {
+	__glibcxx_assert(__position != end());
+	_M_erase_aux(__position);
+      }
+
+      void
+      erase(const_iterator __position)
+      {
+	__glibcxx_assert(__position != end());
+	_M_erase_aux(__position);
+      }
+#endif
+
+      size_type
+      erase(const key_type& __x);
+
+#if __cplusplus >= 201103L
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // DR 130. Associative erase should return an iterator.
+      _GLIBCXX_ABI_TAG_CXX11
+      iterator
+      erase(const_iterator __first, const_iterator __last)
+      {
+	_M_erase_aux(__first, __last);
+	return __last._M_const_cast();
+      }
+#else
+      void
+      erase(iterator __first, iterator __last)
+      { _M_erase_aux(__first, __last); }
+
+      void
+      erase(const_iterator __first, const_iterator __last)
+      { _M_erase_aux(__first, __last); }
+#endif
+
+      void
+      clear() _GLIBCXX_NOEXCEPT
+      {
+	_M_erase(_M_begin());
+	_M_impl._M_reset();
+      }
+
+      // Set operations.
+      iterator
+      find(const key_type& __k);
+
+      const_iterator
+      find(const key_type& __k) const;
+
+      size_type
+      count(const key_type& __k) const;
+
+      iterator
+      lower_bound(const key_type& __k)
+      { return _M_lower_bound(_M_begin(), _M_end(), __k); }
+
+      const_iterator
+      lower_bound(const key_type& __k) const
+      { return _M_lower_bound(_M_begin(), _M_end(), __k); }
+
+      iterator
+      upper_bound(const key_type& __k)
+      { return _M_upper_bound(_M_begin(), _M_end(), __k); }
+
+      const_iterator
+      upper_bound(const key_type& __k) const
+      { return _M_upper_bound(_M_begin(), _M_end(), __k); }
+
+      pair<iterator, iterator>
+      equal_range(const key_type& __k);
+
+      pair<const_iterator, const_iterator>
+      equal_range(const key_type& __k) const;
+
+#if __cplusplus >= 201402L
+      template<typename _Kt,
+	       typename _Req = __has_is_transparent_t<_Compare, _Kt>>
+	iterator
+	_M_find_tr(const _Kt& __k)
+	{
+	  const _Rb_tree* __const_this = this;
+	  return __const_this->_M_find_tr(__k)._M_const_cast();
+	}
+
+      template<typename _Kt,
+	       typename _Req = __has_is_transparent_t<_Compare, _Kt>>
+	const_iterator
+	_M_find_tr(const _Kt& __k) const
+	{
+	  auto __j = _M_lower_bound_tr(__k);
+	  if (__j != end() && _M_impl._M_key_compare(__k, _S_key(__j._M_node)))
+	    __j = end();
+	  return __j;
+	}
+
+      template<typename _Kt,
+	       typename _Req = __has_is_transparent_t<_Compare, _Kt>>
+	size_type
+	_M_count_tr(const _Kt& __k) const
+	{
+	  auto __p = _M_equal_range_tr(__k);
+	  return std::distance(__p.first, __p.second);
+	}
+
+      template<typename _Kt,
+	       typename _Req = __has_is_transparent_t<_Compare, _Kt>>
+	iterator
+	_M_lower_bound_tr(const _Kt& __k)
+	{
+	  const _Rb_tree* __const_this = this;
+	  return __const_this->_M_lower_bound_tr(__k)._M_const_cast();
+	}
+
+      template<typename _Kt,
+	       typename _Req = __has_is_transparent_t<_Compare, _Kt>>
+	const_iterator
+	_M_lower_bound_tr(const _Kt& __k) const
+	{
+	  auto __x = _M_begin();
+	  auto __y = _M_end();
+	  while (__x != 0)
+	    if (!_M_impl._M_key_compare(_S_key(__x), __k))
+	      {
+		__y = __x;
+		__x = _S_left(__x);
+	      }
+	    else
+	      __x = _S_right(__x);
+	  return const_iterator(__y);
+	}
+
+      template<typename _Kt,
+	       typename _Req = __has_is_transparent_t<_Compare, _Kt>>
+	iterator
+	_M_upper_bound_tr(const _Kt& __k)
+	{
+	  const _Rb_tree* __const_this = this;
+	  return __const_this->_M_upper_bound_tr(__k)._M_const_cast();
+	}
+
+      template<typename _Kt,
+	       typename _Req = __has_is_transparent_t<_Compare, _Kt>>
+	const_iterator
+	_M_upper_bound_tr(const _Kt& __k) const
+	{
+	  auto __x = _M_begin();
+	  auto __y = _M_end();
+	  while (__x != 0)
+	    if (_M_impl._M_key_compare(__k, _S_key(__x)))
+	      {
+		__y = __x;
+		__x = _S_left(__x);
+	      }
+	    else
+	      __x = _S_right(__x);
+	  return const_iterator(__y);
+	}
+
+      template<typename _Kt,
+	       typename _Req = __has_is_transparent_t<_Compare, _Kt>>
+	pair<iterator, iterator>
+	_M_equal_range_tr(const _Kt& __k)
+	{
+	  const _Rb_tree* __const_this = this;
+	  auto __ret = __const_this->_M_equal_range_tr(__k);
+	  return { __ret.first._M_const_cast(), __ret.second._M_const_cast() };
+	}
+
+      template<typename _Kt,
+	       typename _Req = __has_is_transparent_t<_Compare, _Kt>>
+	pair<const_iterator, const_iterator>
+	_M_equal_range_tr(const _Kt& __k) const
+	{
+	  auto __low = _M_lower_bound_tr(__k);
+	  auto __high = __low;
+	  auto& __cmp = _M_impl._M_key_compare;
+	  while (__high != end() && !__cmp(__k, _S_key(__high._M_node)))
+	    ++__high;
+	  return { __low, __high };
+	}
+#endif
+
+      // Debugging.
+      bool
+      __rb_verify() const;
+
+#if __cplusplus >= 201103L
+      _Rb_tree&
+      operator=(_Rb_tree&&)
+      noexcept(_Alloc_traits::_S_nothrow_move()
+	       && is_nothrow_move_assignable<_Compare>::value);
+
+      template<typename _Iterator>
+	void
+	_M_assign_unique(_Iterator, _Iterator);
+
+      template<typename _Iterator>
+	void
+	_M_assign_equal(_Iterator, _Iterator);
+
+    private:
+      // Move elements from container with equal allocator.
+      void
+      _M_move_data(_Rb_tree& __x, true_type)
+      { _M_impl._M_move_data(__x._M_impl); }
+
+      // Move elements from container with possibly non-equal allocator,
+      // which might result in a copy not a move.
+      void
+      _M_move_data(_Rb_tree&, false_type);
+
+      // Move assignment from container with equal allocator.
+      void
+      _M_move_assign(_Rb_tree&, true_type);
+
+      // Move assignment from container with possibly non-equal allocator,
+      // which might result in a copy not a move.
+      void
+      _M_move_assign(_Rb_tree&, false_type);
+#endif
+
+#if __cplusplus > 201402L
+    public:
+      /// Re-insert an extracted node.
+      insert_return_type
+      _M_reinsert_node_unique(node_type&& __nh)
+      {
+	insert_return_type __ret;
+	if (__nh.empty())
+	  __ret.position = end();
+	else
+	  {
+	    __glibcxx_assert(_M_get_Node_allocator() == *__nh._M_alloc);
+
+	    auto __res = _M_get_insert_unique_pos(__nh._M_key());
+	    if (__res.second)
+	      {
+		__ret.position
+		  = _M_insert_node(__res.first, __res.second, __nh._M_ptr);
+		__nh._M_ptr = nullptr;
+		__ret.inserted = true;
+	      }
+	    else
+	      {
+		__ret.node = std::move(__nh);
+		__ret.position = iterator(__res.first);
+		__ret.inserted = false;
+	      }
+	  }
+	return __ret;
+      }
+
+      /// Re-insert an extracted node.
+      iterator
+      _M_reinsert_node_equal(node_type&& __nh)
+      {
+	iterator __ret;
+	if (__nh.empty())
+	  __ret = end();
+	else
+	  {
+	    __glibcxx_assert(_M_get_Node_allocator() == *__nh._M_alloc);
+	    auto __res = _M_get_insert_equal_pos(__nh._M_key());
+	    if (__res.second)
+	      __ret = _M_insert_node(__res.first, __res.second, __nh._M_ptr);
+	    else
+	      __ret = _M_insert_equal_lower_node(__nh._M_ptr);
+	    __nh._M_ptr = nullptr;
+	  }
+	return __ret;
+      }
+
+      /// Re-insert an extracted node.
+      iterator
+      _M_reinsert_node_hint_unique(const_iterator __hint, node_type&& __nh)
+      {
+	iterator __ret;
+	if (__nh.empty())
+	  __ret = end();
+	else
+	  {
+	    __glibcxx_assert(_M_get_Node_allocator() == *__nh._M_alloc);
+	    auto __res = _M_get_insert_hint_unique_pos(__hint, __nh._M_key());
+	    if (__res.second)
+	      {
+		__ret = _M_insert_node(__res.first, __res.second, __nh._M_ptr);
+		__nh._M_ptr = nullptr;
+	      }
+	    else
+	      __ret = iterator(__res.first);
+	  }
+	return __ret;
+      }
+
+      /// Re-insert an extracted node.
+      iterator
+      _M_reinsert_node_hint_equal(const_iterator __hint, node_type&& __nh)
+      {
+	iterator __ret;
+	if (__nh.empty())
+	  __ret = end();
+	else
+	  {
+	    __glibcxx_assert(_M_get_Node_allocator() == *__nh._M_alloc);
+	    auto __res = _M_get_insert_hint_equal_pos(__hint, __nh._M_key());
+	    if (__res.second)
+	      __ret = _M_insert_node(__res.first, __res.second, __nh._M_ptr);
+	    else
+	      __ret = _M_insert_equal_lower_node(__nh._M_ptr);
+	    __nh._M_ptr = nullptr;
+	  }
+	return __ret;
+      }
+
+      /// Extract a node.
+      node_type
+      extract(const_iterator __pos)
+      {
+	auto __ptr = _Rb_tree_rebalance_for_erase(
+	    __pos._M_const_cast()._M_node, _M_impl._M_header);
+	--_M_impl._M_node_count;
+	return { static_cast<_Link_type>(__ptr), _M_get_Node_allocator() };
+      }
+
+      /// Extract a node.
+      node_type
+      extract(const key_type& __k)
+      {
+	node_type __nh;
+	auto __pos = find(__k);
+	if (__pos != end())
+	  __nh = extract(const_iterator(__pos));
+	return __nh;
+      }
+
+      template<typename _Compare2>
+	using _Compatible_tree
+	  = _Rb_tree<_Key, _Val, _KeyOfValue, _Compare2, _Alloc>;
+
+      template<typename, typename>
+	friend class _Rb_tree_merge_helper;
+
+      /// Merge from a compatible container into one with unique keys.
+      template<typename _Compare2>
+	void
+	_M_merge_unique(_Compatible_tree<_Compare2>& __src) noexcept
+	{
+	  using _Merge_helper = _Rb_tree_merge_helper<_Rb_tree, _Compare2>;
+	  for (auto __i = __src.begin(), __end = __src.end(); __i != __end;)
+	    {
+	      auto __pos = __i++;
+	      auto __res = _M_get_insert_unique_pos(_KeyOfValue()(*__pos));
+	      if (__res.second)
+		{
+		  auto& __src_impl = _Merge_helper::_S_get_impl(__src);
+		  auto __ptr = _Rb_tree_rebalance_for_erase(
+		      __pos._M_node, __src_impl._M_header);
+		  --__src_impl._M_node_count;
+		  _M_insert_node(__res.first, __res.second,
+				 static_cast<_Link_type>(__ptr));
+		}
+	    }
+	}
+
+      /// Merge from a compatible container into one with equivalent keys.
+      template<typename _Compare2>
+	void
+	_M_merge_equal(_Compatible_tree<_Compare2>& __src) noexcept
+	{
+	  using _Merge_helper = _Rb_tree_merge_helper<_Rb_tree, _Compare2>;
+	  for (auto __i = __src.begin(), __end = __src.end(); __i != __end;)
+	    {
+	      auto __pos = __i++;
+	      auto __res = _M_get_insert_equal_pos(_KeyOfValue()(*__pos));
+	      if (__res.second)
+		{
+		  auto& __src_impl = _Merge_helper::_S_get_impl(__src);
+		  auto __ptr = _Rb_tree_rebalance_for_erase(
+		      __pos._M_node, __src_impl._M_header);
+		  --__src_impl._M_node_count;
+		  _M_insert_node(__res.first, __res.second,
+				 static_cast<_Link_type>(__ptr));
+		}
+	    }
+	}
+#endif // C++17
+
+      friend bool
+      operator==(const _Rb_tree& __x, const _Rb_tree& __y)
+      {
+	return __x.size() == __y.size()
+	  && std::equal(__x.begin(), __x.end(), __y.begin());
+      }
+
+#if __cpp_lib_three_way_comparison
+      friend auto
+      operator<=>(const _Rb_tree& __x, const _Rb_tree& __y)
+      {
+	if constexpr (requires { typename __detail::__synth3way_t<_Val>; })
+	  return std::lexicographical_compare_three_way(__x.begin(), __x.end(),
+							__y.begin(), __y.end(),
+							__detail::__synth3way);
+      }
+#else
+      friend bool
+      operator<(const _Rb_tree& __x, const _Rb_tree& __y)
+      {
+	return std::lexicographical_compare(__x.begin(), __x.end(),
+					    __y.begin(), __y.end());
+      }
+#endif
+
+    private:
+#if __cplusplus >= 201103L
+      // An RAII _Node handle
+      struct _Auto_node
+      {
+	template<typename... _Args>
+	  _Auto_node(_Rb_tree& __t, _Args&&... __args)
+	  : _M_t(__t),
+	    _M_node(__t._M_create_node(std::forward<_Args>(__args)...))
+	  { }
+
+	~_Auto_node()
+	{
+	  if (_M_node)
+	    _M_t._M_drop_node(_M_node);
+	}
+
+	_Auto_node(_Auto_node&& __n)
+	: _M_t(__n._M_t), _M_node(__n._M_node)
+	{ __n._M_node = nullptr; }
+
+	const _Key&
+	_M_key() const
+	{ return _S_key(_M_node); }
+
+	iterator
+	_M_insert(pair<_Base_ptr, _Base_ptr> __p)
+	{
+	  auto __it = _M_t._M_insert_node(__p.first, __p.second, _M_node);
+	  _M_node = nullptr;
+	  return __it;
+	}
+
+	iterator
+	_M_insert_equal_lower()
+	{
+	  auto __it = _M_t._M_insert_equal_lower_node(_M_node);
+	  _M_node = nullptr;
+	  return __it;
+	}
+
+	_Rb_tree& _M_t;
+	_Link_type _M_node;
+      };
+#endif // C++11
+    };
+
+  template<typename _Key, typename _Val, typename _KeyOfValue,
+	   typename _Compare, typename _Alloc>
+    inline void
+    swap(_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>& __x,
+	 _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>& __y)
+    { __x.swap(__y); }
+
+#if __cplusplus >= 201103L
+  template<typename _Key, typename _Val, typename _KeyOfValue,
+	   typename _Compare, typename _Alloc>
+    void
+    _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::
+    _M_move_data(_Rb_tree& __x, false_type)
+    {
+      if (_M_get_Node_allocator() == __x._M_get_Node_allocator())
+	_M_move_data(__x, true_type());
+      else
+	{
+	  constexpr bool __move = !__move_if_noexcept_cond<value_type>::value;
+	  _Alloc_node __an(*this);
+	  _M_root() = _M_copy<__move>(__x, __an);
+	  if _GLIBCXX17_CONSTEXPR (__move)
+	    __x.clear();
+	}
+    }
+
+  template<typename _Key, typename _Val, typename _KeyOfValue,
+	   typename _Compare, typename _Alloc>
+    inline void
+    _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::
+    _M_move_assign(_Rb_tree& __x, true_type)
+    {
+      clear();
+      if (__x._M_root() != nullptr)
+	_M_move_data(__x, true_type());
+      std::__alloc_on_move(_M_get_Node_allocator(),
+			   __x._M_get_Node_allocator());
+    }
+
+  template<typename _Key, typename _Val, typename _KeyOfValue,
+	   typename _Compare, typename _Alloc>
+    void
+    _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::
+    _M_move_assign(_Rb_tree& __x, false_type)
+    {
+      if (_M_get_Node_allocator() == __x._M_get_Node_allocator())
+	return _M_move_assign(__x, true_type{});
+
+      // Try to move each node reusing existing nodes and copying __x nodes
+      // structure.
+      _Reuse_or_alloc_node __roan(*this);
+      _M_impl._M_reset();
+      if (__x._M_root() != nullptr)
+	{
+	  _M_root() = _M_copy<__as_rvalue>(__x, __roan);
+	  __x.clear();
+	}
+    }
+
+  template<typename _Key, typename _Val, typename _KeyOfValue,
+	   typename _Compare, typename _Alloc>
+    inline _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>&
+    _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::
+    operator=(_Rb_tree&& __x)
+    noexcept(_Alloc_traits::_S_nothrow_move()
+	     && is_nothrow_move_assignable<_Compare>::value)
+    {
+      _M_impl._M_key_compare = std::move(__x._M_impl._M_key_compare);
+      _M_move_assign(__x, __bool_constant<_Alloc_traits::_S_nothrow_move()>());
+      return *this;
+    }
+
+  template<typename _Key, typename _Val, typename _KeyOfValue,
+	   typename _Compare, typename _Alloc>
+    template<typename _Iterator>
+      void
+      _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::
+      _M_assign_unique(_Iterator __first, _Iterator __last)
+      {
+	_Reuse_or_alloc_node __roan(*this);
+	_M_impl._M_reset();
+	for (; __first != __last; ++__first)
+	  _M_insert_unique_(end(), *__first, __roan);
+      }
+
+  template<typename _Key, typename _Val, typename _KeyOfValue,
+	   typename _Compare, typename _Alloc>
+    template<typename _Iterator>
+      void
+      _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::
+      _M_assign_equal(_Iterator __first, _Iterator __last)
+      {
+	_Reuse_or_alloc_node __roan(*this);
+	_M_impl._M_reset();
+	for (; __first != __last; ++__first)
+	  _M_insert_equal_(end(), *__first, __roan);
+      }
+#endif
+
+  template<typename _Key, typename _Val, typename _KeyOfValue,
+	   typename _Compare, typename _Alloc>
+    _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>&
+    _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::
+    operator=(const _Rb_tree& __x)
+    {
+      if (this != std::__addressof(__x))
+	{
+	  // Note that _Key may be a constant type.
+#if __cplusplus >= 201103L
+	  if (_Alloc_traits::_S_propagate_on_copy_assign())
+	    {
+	      auto& __this_alloc = this->_M_get_Node_allocator();
+	      auto& __that_alloc = __x._M_get_Node_allocator();
+	      if (!_Alloc_traits::_S_always_equal()
+		  && __this_alloc != __that_alloc)
+		{
+		  // Replacement allocator cannot free existing storage, we need
+		  // to erase nodes first.
+		  clear();
+		  std::__alloc_on_copy(__this_alloc, __that_alloc);
+		}
+	    }
+#endif
+
+	  _Reuse_or_alloc_node __roan(*this);
+	  _M_impl._M_reset();
+	  _M_impl._M_key_compare = __x._M_impl._M_key_compare;
+	  if (__x._M_root() != 0)
+	    _M_root() = _M_copy<__as_lvalue>(__x, __roan);
+	}
+
+      return *this;
+    }
+
+  template<typename _Key, typename _Val, typename _KeyOfValue,
+	   typename _Compare, typename _Alloc>
+#if __cplusplus >= 201103L
+    template<typename _Arg, typename _NodeGen>
+#else
+    template<typename _NodeGen>
+#endif
+      typename _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::iterator
+      _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::
+      _M_insert_(_Base_ptr __x, _Base_ptr __p,
+#if __cplusplus >= 201103L
+		 _Arg&& __v,
+#else
+		 const _Val& __v,
+#endif
+		 _NodeGen& __node_gen)
+      {
+	bool __insert_left = (__x != 0 || __p == _M_end()
+			      || _M_impl._M_key_compare(_KeyOfValue()(__v),
+							_S_key(__p)));
+
+	_Link_type __z = __node_gen(_GLIBCXX_FORWARD(_Arg, __v));
+
+	_Rb_tree_insert_and_rebalance(__insert_left, __z, __p,
+				      this->_M_impl._M_header);
+	++_M_impl._M_node_count;
+	return iterator(__z);
+      }
+
+  template<typename _Key, typename _Val, typename _KeyOfValue,
+	   typename _Compare, typename _Alloc>
+#if __cplusplus >= 201103L
+    template<typename _Arg>
+#endif
+    typename _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::iterator
+    _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::
+#if __cplusplus >= 201103L
+    _M_insert_lower(_Base_ptr __p, _Arg&& __v)
+#else
+    _M_insert_lower(_Base_ptr __p, const _Val& __v)
+#endif
+    {
+      bool __insert_left = (__p == _M_end()
+			    || !_M_impl._M_key_compare(_S_key(__p),
+						       _KeyOfValue()(__v)));
+
+      _Link_type __z = _M_create_node(_GLIBCXX_FORWARD(_Arg, __v));
+
+      _Rb_tree_insert_and_rebalance(__insert_left, __z, __p,
+				    this->_M_impl._M_header);
+      ++_M_impl._M_node_count;
+      return iterator(__z);
+    }
+
+  template<typename _Key, typename _Val, typename _KeyOfValue,
+	   typename _Compare, typename _Alloc>
+#if __cplusplus >= 201103L
+    template<typename _Arg>
+#endif
+    typename _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::iterator
+    _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::
+#if __cplusplus >= 201103L
+    _M_insert_equal_lower(_Arg&& __v)
+#else
+    _M_insert_equal_lower(const _Val& __v)
+#endif
+    {
+      _Link_type __x = _M_begin();
+      _Base_ptr __y = _M_end();
+      while (__x != 0)
+	{
+	  __y = __x;
+	  __x = !_M_impl._M_key_compare(_S_key(__x), _KeyOfValue()(__v)) ?
+		_S_left(__x) : _S_right(__x);
+	}
+      return _M_insert_lower(__y, _GLIBCXX_FORWARD(_Arg, __v));
+    }
+
+  template<typename _Key, typename _Val, typename _KoV,
+	   typename _Compare, typename _Alloc>
+    template<bool _MoveValues, typename _NodeGen>
+      typename _Rb_tree<_Key, _Val, _KoV, _Compare, _Alloc>::_Link_type
+      _Rb_tree<_Key, _Val, _KoV, _Compare, _Alloc>::
+      _M_copy(_Link_type __x, _Base_ptr __p, _NodeGen& __node_gen)
+      {
+	// Structural copy. __x and __p must be non-null.
+	_Link_type __top = _M_clone_node<_MoveValues>(__x, __node_gen);
+	__top->_M_parent = __p;
+
+	__try
+	  {
+	    if (__x->_M_right)
+	      __top->_M_right =
+		_M_copy<_MoveValues>(_S_right(__x), __top, __node_gen);
+	    __p = __top;
+	    __x = _S_left(__x);
+
+	    while (__x != 0)
+	      {
+		_Link_type __y = _M_clone_node<_MoveValues>(__x, __node_gen);
+		__p->_M_left = __y;
+		__y->_M_parent = __p;
+		if (__x->_M_right)
+		  __y->_M_right = _M_copy<_MoveValues>(_S_right(__x),
+						       __y, __node_gen);
+		__p = __y;
+		__x = _S_left(__x);
+	      }
+	  }
+	__catch(...)
+	  {
+	    _M_erase(__top);
+	    __throw_exception_again;
+	  }
+	return __top;
+      }
+
+  template<typename _Key, typename _Val, typename _KeyOfValue,
+	   typename _Compare, typename _Alloc>
+    void
+    _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::
+    _M_erase(_Link_type __x)
+    {
+      // Erase without rebalancing.
+      while (__x != 0)
+	{
+	  _M_erase(_S_right(__x));
+	  _Link_type __y = _S_left(__x);
+	  _M_drop_node(__x);
+	  __x = __y;
+	}
+    }
+
+  template<typename _Key, typename _Val, typename _KeyOfValue,
+	   typename _Compare, typename _Alloc>
+    typename _Rb_tree<_Key, _Val, _KeyOfValue,
+		      _Compare, _Alloc>::iterator
+    _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::
+    _M_lower_bound(_Link_type __x, _Base_ptr __y,
+		   const _Key& __k)
+    {
+      while (__x != 0)
+	if (!_M_impl._M_key_compare(_S_key(__x), __k))
+	  __y = __x, __x = _S_left(__x);
+	else
+	  __x = _S_right(__x);
+      return iterator(__y);
+    }
+
+  template<typename _Key, typename _Val, typename _KeyOfValue,
+	   typename _Compare, typename _Alloc>
+    typename _Rb_tree<_Key, _Val, _KeyOfValue,
+		      _Compare, _Alloc>::const_iterator
+    _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::
+    _M_lower_bound(_Const_Link_type __x, _Const_Base_ptr __y,
+		   const _Key& __k) const
+    {
+      while (__x != 0)
+	if (!_M_impl._M_key_compare(_S_key(__x), __k))
+	  __y = __x, __x = _S_left(__x);
+	else
+	  __x = _S_right(__x);
+      return const_iterator(__y);
+    }
+
+  template<typename _Key, typename _Val, typename _KeyOfValue,
+	   typename _Compare, typename _Alloc>
+    typename _Rb_tree<_Key, _Val, _KeyOfValue,
+		      _Compare, _Alloc>::iterator
+    _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::
+    _M_upper_bound(_Link_type __x, _Base_ptr __y,
+		   const _Key& __k)
+    {
+      while (__x != 0)
+	if (_M_impl._M_key_compare(__k, _S_key(__x)))
+	  __y = __x, __x = _S_left(__x);
+	else
+	  __x = _S_right(__x);
+      return iterator(__y);
+    }
+
+  template<typename _Key, typename _Val, typename _KeyOfValue,
+	   typename _Compare, typename _Alloc>
+    typename _Rb_tree<_Key, _Val, _KeyOfValue,
+		      _Compare, _Alloc>::const_iterator
+    _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::
+    _M_upper_bound(_Const_Link_type __x, _Const_Base_ptr __y,
+		   const _Key& __k) const
+    {
+      while (__x != 0)
+	if (_M_impl._M_key_compare(__k, _S_key(__x)))
+	  __y = __x, __x = _S_left(__x);
+	else
+	  __x = _S_right(__x);
+      return const_iterator(__y);
+    }
+
+  template<typename _Key, typename _Val, typename _KeyOfValue,
+	   typename _Compare, typename _Alloc>
+    pair<typename _Rb_tree<_Key, _Val, _KeyOfValue,
+			   _Compare, _Alloc>::iterator,
+	 typename _Rb_tree<_Key, _Val, _KeyOfValue,
+			   _Compare, _Alloc>::iterator>
+    _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::
+    equal_range(const _Key& __k)
+    {
+      _Link_type __x = _M_begin();
+      _Base_ptr __y = _M_end();
+      while (__x != 0)
+	{
+	  if (_M_impl._M_key_compare(_S_key(__x), __k))
+	    __x = _S_right(__x);
+	  else if (_M_impl._M_key_compare(__k, _S_key(__x)))
+	    __y = __x, __x = _S_left(__x);
+	  else
+	    {
+	      _Link_type __xu(__x);
+	      _Base_ptr __yu(__y);
+	      __y = __x, __x = _S_left(__x);
+	      __xu = _S_right(__xu);
+	      return pair<iterator,
+			  iterator>(_M_lower_bound(__x, __y, __k),
+				    _M_upper_bound(__xu, __yu, __k));
+	    }
+	}
+      return pair<iterator, iterator>(iterator(__y),
+				      iterator(__y));
+    }
+
+  template<typename _Key, typename _Val, typename _KeyOfValue,
+	   typename _Compare, typename _Alloc>
+    pair<typename _Rb_tree<_Key, _Val, _KeyOfValue,
+			   _Compare, _Alloc>::const_iterator,
+	 typename _Rb_tree<_Key, _Val, _KeyOfValue,
+			   _Compare, _Alloc>::const_iterator>
+    _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::
+    equal_range(const _Key& __k) const
+    {
+      _Const_Link_type __x = _M_begin();
+      _Const_Base_ptr __y = _M_end();
+      while (__x != 0)
+	{
+	  if (_M_impl._M_key_compare(_S_key(__x), __k))
+	    __x = _S_right(__x);
+	  else if (_M_impl._M_key_compare(__k, _S_key(__x)))
+	    __y = __x, __x = _S_left(__x);
+	  else
+	    {
+	      _Const_Link_type __xu(__x);
+	      _Const_Base_ptr __yu(__y);
+	      __y = __x, __x = _S_left(__x);
+	      __xu = _S_right(__xu);
+	      return pair<const_iterator,
+			  const_iterator>(_M_lower_bound(__x, __y, __k),
+					  _M_upper_bound(__xu, __yu, __k));
+	    }
+	}
+      return pair<const_iterator, const_iterator>(const_iterator(__y),
+						  const_iterator(__y));
+    }
+
+  template<typename _Key, typename _Val, typename _KeyOfValue,
+	   typename _Compare, typename _Alloc>
+    void
+    _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::
+    swap(_Rb_tree& __t)
+    _GLIBCXX_NOEXCEPT_IF(__is_nothrow_swappable<_Compare>::value)
+    {
+      if (_M_root() == 0)
+	{
+	  if (__t._M_root() != 0)
+	    _M_impl._M_move_data(__t._M_impl);
+	}
+      else if (__t._M_root() == 0)
+	__t._M_impl._M_move_data(_M_impl);
+      else
+	{
+	  std::swap(_M_root(),__t._M_root());
+	  std::swap(_M_leftmost(),__t._M_leftmost());
+	  std::swap(_M_rightmost(),__t._M_rightmost());
+
+	  _M_root()->_M_parent = _M_end();
+	  __t._M_root()->_M_parent = __t._M_end();
+	  std::swap(this->_M_impl._M_node_count, __t._M_impl._M_node_count);
+	}
+      // No need to swap header's color as it does not change.
+      std::swap(this->_M_impl._M_key_compare, __t._M_impl._M_key_compare);
+
+      _Alloc_traits::_S_on_swap(_M_get_Node_allocator(),
+				__t._M_get_Node_allocator());
+    }
+
+  template<typename _Key, typename _Val, typename _KeyOfValue,
+	   typename _Compare, typename _Alloc>
+    pair<typename _Rb_tree<_Key, _Val, _KeyOfValue,
+			   _Compare, _Alloc>::_Base_ptr,
+	 typename _Rb_tree<_Key, _Val, _KeyOfValue,
+			   _Compare, _Alloc>::_Base_ptr>
+    _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::
+    _M_get_insert_unique_pos(const key_type& __k)
+    {
+      typedef pair<_Base_ptr, _Base_ptr> _Res;
+      _Link_type __x = _M_begin();
+      _Base_ptr __y = _M_end();
+      bool __comp = true;
+      while (__x != 0)
+	{
+	  __y = __x;
+	  __comp = _M_impl._M_key_compare(__k, _S_key(__x));
+	  __x = __comp ? _S_left(__x) : _S_right(__x);
+	}
+      iterator __j = iterator(__y);
+      if (__comp)
+	{
+	  if (__j == begin())
+	    return _Res(__x, __y);
+	  else
+	    --__j;
+	}
+      if (_M_impl._M_key_compare(_S_key(__j._M_node), __k))
+	return _Res(__x, __y);
+      return _Res(__j._M_node, 0);
+    }
+
+  template<typename _Key, typename _Val, typename _KeyOfValue,
+	   typename _Compare, typename _Alloc>
+    pair<typename _Rb_tree<_Key, _Val, _KeyOfValue,
+			   _Compare, _Alloc>::_Base_ptr,
+	 typename _Rb_tree<_Key, _Val, _KeyOfValue,
+			   _Compare, _Alloc>::_Base_ptr>
+    _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::
+    _M_get_insert_equal_pos(const key_type& __k)
+    {
+      typedef pair<_Base_ptr, _Base_ptr> _Res;
+      _Link_type __x = _M_begin();
+      _Base_ptr __y = _M_end();
+      while (__x != 0)
+	{
+	  __y = __x;
+	  __x = _M_impl._M_key_compare(__k, _S_key(__x)) ?
+		_S_left(__x) : _S_right(__x);
+	}
+      return _Res(__x, __y);
+    }
+
+  template<typename _Key, typename _Val, typename _KeyOfValue,
+	   typename _Compare, typename _Alloc>
+#if __cplusplus >= 201103L
+    template<typename _Arg>
+#endif
+    pair<typename _Rb_tree<_Key, _Val, _KeyOfValue,
+			   _Compare, _Alloc>::iterator, bool>
+    _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::
+#if __cplusplus >= 201103L
+    _M_insert_unique(_Arg&& __v)
+#else
+    _M_insert_unique(const _Val& __v)
+#endif
+    {
+      typedef pair<iterator, bool> _Res;
+      pair<_Base_ptr, _Base_ptr> __res
+	= _M_get_insert_unique_pos(_KeyOfValue()(__v));
+
+      if (__res.second)
+	{
+	  _Alloc_node __an(*this);
+	  return _Res(_M_insert_(__res.first, __res.second,
+				 _GLIBCXX_FORWARD(_Arg, __v), __an),
+		      true);
+	}
+
+      return _Res(iterator(__res.first), false);
+    }
+
+  template<typename _Key, typename _Val, typename _KeyOfValue,
+	   typename _Compare, typename _Alloc>
+#if __cplusplus >= 201103L
+    template<typename _Arg>
+#endif
+    typename _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::iterator
+    _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::
+#if __cplusplus >= 201103L
+    _M_insert_equal(_Arg&& __v)
+#else
+    _M_insert_equal(const _Val& __v)
+#endif
+    {
+      pair<_Base_ptr, _Base_ptr> __res
+	= _M_get_insert_equal_pos(_KeyOfValue()(__v));
+      _Alloc_node __an(*this);
+      return _M_insert_(__res.first, __res.second,
+			_GLIBCXX_FORWARD(_Arg, __v), __an);
+    }
+
+  template<typename _Key, typename _Val, typename _KeyOfValue,
+	   typename _Compare, typename _Alloc>
+    pair<typename _Rb_tree<_Key, _Val, _KeyOfValue,
+			   _Compare, _Alloc>::_Base_ptr,
+	 typename _Rb_tree<_Key, _Val, _KeyOfValue,
+			   _Compare, _Alloc>::_Base_ptr>
+    _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::
+    _M_get_insert_hint_unique_pos(const_iterator __position,
+				  const key_type& __k)
+    {
+      iterator __pos = __position._M_const_cast();
+      typedef pair<_Base_ptr, _Base_ptr> _Res;
+
+      // end()
+      if (__pos._M_node == _M_end())
+	{
+	  if (size() > 0
+	      && _M_impl._M_key_compare(_S_key(_M_rightmost()), __k))
+	    return _Res(0, _M_rightmost());
+	  else
+	    return _M_get_insert_unique_pos(__k);
+	}
+      else if (_M_impl._M_key_compare(__k, _S_key(__pos._M_node)))
+	{
+	  // First, try before...
+	  iterator __before = __pos;
+	  if (__pos._M_node == _M_leftmost()) // begin()
+	    return _Res(_M_leftmost(), _M_leftmost());
+	  else if (_M_impl._M_key_compare(_S_key((--__before)._M_node), __k))
+	    {
+	      if (_S_right(__before._M_node) == 0)
+		return _Res(0, __before._M_node);
+	      else
+		return _Res(__pos._M_node, __pos._M_node);
+	    }
+	  else
+	    return _M_get_insert_unique_pos(__k);
+	}
+      else if (_M_impl._M_key_compare(_S_key(__pos._M_node), __k))
+	{
+	  // ... then try after.
+	  iterator __after = __pos;
+	  if (__pos._M_node == _M_rightmost())
+	    return _Res(0, _M_rightmost());
+	  else if (_M_impl._M_key_compare(__k, _S_key((++__after)._M_node)))
+	    {
+	      if (_S_right(__pos._M_node) == 0)
+		return _Res(0, __pos._M_node);
+	      else
+		return _Res(__after._M_node, __after._M_node);
+	    }
+	  else
+	    return _M_get_insert_unique_pos(__k);
+	}
+      else
+	// Equivalent keys.
+	return _Res(__pos._M_node, 0);
+    }
+
+  template<typename _Key, typename _Val, typename _KeyOfValue,
+	   typename _Compare, typename _Alloc>
+#if __cplusplus >= 201103L
+    template<typename _Arg, typename _NodeGen>
+#else
+    template<typename _NodeGen>
+#endif
+      typename _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::iterator
+      _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::
+      _M_insert_unique_(const_iterator __position,
+#if __cplusplus >= 201103L
+			_Arg&& __v,
+#else
+			const _Val& __v,
+#endif
+			_NodeGen& __node_gen)
+    {
+      pair<_Base_ptr, _Base_ptr> __res
+	= _M_get_insert_hint_unique_pos(__position, _KeyOfValue()(__v));
+
+      if (__res.second)
+	return _M_insert_(__res.first, __res.second,
+			  _GLIBCXX_FORWARD(_Arg, __v),
+			  __node_gen);
+      return iterator(__res.first);
+    }
+
+  template<typename _Key, typename _Val, typename _KeyOfValue,
+	   typename _Compare, typename _Alloc>
+    pair<typename _Rb_tree<_Key, _Val, _KeyOfValue,
+			   _Compare, _Alloc>::_Base_ptr,
+	 typename _Rb_tree<_Key, _Val, _KeyOfValue,
+			   _Compare, _Alloc>::_Base_ptr>
+    _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::
+    _M_get_insert_hint_equal_pos(const_iterator __position, const key_type& __k)
+    {
+      iterator __pos = __position._M_const_cast();
+      typedef pair<_Base_ptr, _Base_ptr> _Res;
+
+      // end()
+      if (__pos._M_node == _M_end())
+	{
+	  if (size() > 0
+	      && !_M_impl._M_key_compare(__k, _S_key(_M_rightmost())))
+	    return _Res(0, _M_rightmost());
+	  else
+	    return _M_get_insert_equal_pos(__k);
+	}
+      else if (!_M_impl._M_key_compare(_S_key(__pos._M_node), __k))
+	{
+	  // First, try before...
+	  iterator __before = __pos;
+	  if (__pos._M_node == _M_leftmost()) // begin()
+	    return _Res(_M_leftmost(), _M_leftmost());
+	  else if (!_M_impl._M_key_compare(__k, _S_key((--__before)._M_node)))
+	    {
+	      if (_S_right(__before._M_node) == 0)
+		return _Res(0, __before._M_node);
+	      else
+		return _Res(__pos._M_node, __pos._M_node);
+	    }
+	  else
+	    return _M_get_insert_equal_pos(__k);
+	}
+      else
+	{
+	  // ... then try after.
+	  iterator __after = __pos;
+	  if (__pos._M_node == _M_rightmost())
+	    return _Res(0, _M_rightmost());
+	  else if (!_M_impl._M_key_compare(_S_key((++__after)._M_node), __k))
+	    {
+	      if (_S_right(__pos._M_node) == 0)
+		return _Res(0, __pos._M_node);
+	      else
+		return _Res(__after._M_node, __after._M_node);
+	    }
+	  else
+	    return _Res(0, 0);
+	}
+    }
+
+  template<typename _Key, typename _Val, typename _KeyOfValue,
+	   typename _Compare, typename _Alloc>
+#if __cplusplus >= 201103L
+    template<typename _Arg, typename _NodeGen>
+#else
+    template<typename _NodeGen>
+#endif
+      typename _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::iterator
+      _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::
+      _M_insert_equal_(const_iterator __position,
+#if __cplusplus >= 201103L
+		       _Arg&& __v,
+#else
+		       const _Val& __v,
+#endif
+		       _NodeGen& __node_gen)
+      {
+	pair<_Base_ptr, _Base_ptr> __res
+	  = _M_get_insert_hint_equal_pos(__position, _KeyOfValue()(__v));
+
+	if (__res.second)
+	  return _M_insert_(__res.first, __res.second,
+			    _GLIBCXX_FORWARD(_Arg, __v),
+			    __node_gen);
+
+	return _M_insert_equal_lower(_GLIBCXX_FORWARD(_Arg, __v));
+      }
+
+#if __cplusplus >= 201103L
+  template<typename _Key, typename _Val, typename _KeyOfValue,
+	   typename _Compare, typename _Alloc>
+    auto
+    _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::
+    _M_insert_node(_Base_ptr __x, _Base_ptr __p, _Link_type __z)
+    -> iterator
+    {
+      bool __insert_left = (__x != 0 || __p == _M_end()
+			    || _M_impl._M_key_compare(_S_key(__z),
+						      _S_key(__p)));
+
+      _Rb_tree_insert_and_rebalance(__insert_left, __z, __p,
+				    this->_M_impl._M_header);
+      ++_M_impl._M_node_count;
+      return iterator(__z);
+    }
+
+  template<typename _Key, typename _Val, typename _KeyOfValue,
+	   typename _Compare, typename _Alloc>
+    auto
+    _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::
+    _M_insert_lower_node(_Base_ptr __p, _Link_type __z)
+    -> iterator
+    {
+      bool __insert_left = (__p == _M_end()
+			    || !_M_impl._M_key_compare(_S_key(__p),
+						       _S_key(__z)));
+
+      _Rb_tree_insert_and_rebalance(__insert_left, __z, __p,
+				    this->_M_impl._M_header);
+      ++_M_impl._M_node_count;
+      return iterator(__z);
+    }
+
+  template<typename _Key, typename _Val, typename _KeyOfValue,
+	   typename _Compare, typename _Alloc>
+    auto
+    _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::
+    _M_insert_equal_lower_node(_Link_type __z)
+    -> iterator
+    {
+      _Link_type __x = _M_begin();
+      _Base_ptr __y = _M_end();
+      while (__x != 0)
+	{
+	  __y = __x;
+	  __x = !_M_impl._M_key_compare(_S_key(__x), _S_key(__z)) ?
+		_S_left(__x) : _S_right(__x);
+	}
+      return _M_insert_lower_node(__y, __z);
+    }
+
+  template<typename _Key, typename _Val, typename _KeyOfValue,
+	   typename _Compare, typename _Alloc>
+    template<typename... _Args>
+      auto
+      _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::
+      _M_emplace_unique(_Args&&... __args)
+      -> pair<iterator, bool>
+      {
+	_Auto_node __z(*this, std::forward<_Args>(__args)...);
+	auto __res = _M_get_insert_unique_pos(__z._M_key());
+	if (__res.second)
+	  return {__z._M_insert(__res), true};
+	return {iterator(__res.first), false};
+      }
+
+  template<typename _Key, typename _Val, typename _KeyOfValue,
+	   typename _Compare, typename _Alloc>
+    template<typename... _Args>
+      auto
+      _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::
+      _M_emplace_equal(_Args&&... __args)
+      -> iterator
+      {
+	_Auto_node __z(*this, std::forward<_Args>(__args)...);
+	auto __res = _M_get_insert_equal_pos(__z._M_key());
+	return __z._M_insert(__res);
+      }
+
+  template<typename _Key, typename _Val, typename _KeyOfValue,
+	   typename _Compare, typename _Alloc>
+    template<typename... _Args>
+      auto
+      _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::
+      _M_emplace_hint_unique(const_iterator __pos, _Args&&... __args)
+      -> iterator
+      {
+	_Auto_node __z(*this, std::forward<_Args>(__args)...);
+	auto __res = _M_get_insert_hint_unique_pos(__pos, __z._M_key());
+	if (__res.second)
+	  return __z._M_insert(__res);
+	return iterator(__res.first);
+      }
+
+  template<typename _Key, typename _Val, typename _KeyOfValue,
+	   typename _Compare, typename _Alloc>
+    template<typename... _Args>
+      auto
+      _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::
+      _M_emplace_hint_equal(const_iterator __pos, _Args&&... __args)
+      -> iterator
+      {
+	_Auto_node __z(*this, std::forward<_Args>(__args)...);
+	auto __res = _M_get_insert_hint_equal_pos(__pos, __z._M_key());
+	if (__res.second)
+	  return __z._M_insert(__res);
+	return __z._M_insert_equal_lower();
+      }
+#endif
+
+
+  template<typename _Key, typename _Val, typename _KeyOfValue,
+	   typename _Compare, typename _Alloc>
+    void
+    _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::
+    _M_erase_aux(const_iterator __position)
+    {
+      _Link_type __y =
+	static_cast<_Link_type>(_Rb_tree_rebalance_for_erase
+				(const_cast<_Base_ptr>(__position._M_node),
+				 this->_M_impl._M_header));
+      _M_drop_node(__y);
+      --_M_impl._M_node_count;
+    }
+
+  template<typename _Key, typename _Val, typename _KeyOfValue,
+	   typename _Compare, typename _Alloc>
+    void
+    _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::
+    _M_erase_aux(const_iterator __first, const_iterator __last)
+    {
+      if (__first == begin() && __last == end())
+	clear();
+      else
+	while (__first != __last)
+	  _M_erase_aux(__first++);
+    }
+
+  template<typename _Key, typename _Val, typename _KeyOfValue,
+	   typename _Compare, typename _Alloc>
+    typename _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::size_type
+    _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::
+    erase(const _Key& __x)
+    {
+      pair<iterator, iterator> __p = equal_range(__x);
+      const size_type __old_size = size();
+      _M_erase_aux(__p.first, __p.second);
+      return __old_size - size();
+    }
+
+  template<typename _Key, typename _Val, typename _KeyOfValue,
+	   typename _Compare, typename _Alloc>
+    typename _Rb_tree<_Key, _Val, _KeyOfValue,
+		      _Compare, _Alloc>::iterator
+    _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::
+    find(const _Key& __k)
+    {
+      iterator __j = _M_lower_bound(_M_begin(), _M_end(), __k);
+      return (__j == end()
+	      || _M_impl._M_key_compare(__k,
+					_S_key(__j._M_node))) ? end() : __j;
+    }
+
+  template<typename _Key, typename _Val, typename _KeyOfValue,
+	   typename _Compare, typename _Alloc>
+    typename _Rb_tree<_Key, _Val, _KeyOfValue,
+		      _Compare, _Alloc>::const_iterator
+    _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::
+    find(const _Key& __k) const
+    {
+      const_iterator __j = _M_lower_bound(_M_begin(), _M_end(), __k);
+      return (__j == end()
+	      || _M_impl._M_key_compare(__k,
+					_S_key(__j._M_node))) ? end() : __j;
+    }
+
+  template<typename _Key, typename _Val, typename _KeyOfValue,
+	   typename _Compare, typename _Alloc>
+    typename _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::size_type
+    _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::
+    count(const _Key& __k) const
+    {
+      pair<const_iterator, const_iterator> __p = equal_range(__k);
+      const size_type __n = std::distance(__p.first, __p.second);
+      return __n;
+    }
+
+  _GLIBCXX_PURE unsigned int
+  _Rb_tree_black_count(const _Rb_tree_node_base* __node,
+		       const _Rb_tree_node_base* __root) throw ();
+
+  template<typename _Key, typename _Val, typename _KeyOfValue,
+	   typename _Compare, typename _Alloc>
+    bool
+    _Rb_tree<_Key,_Val,_KeyOfValue,_Compare,_Alloc>::__rb_verify() const
+    {
+      if (_M_impl._M_node_count == 0 || begin() == end())
+	return _M_impl._M_node_count == 0 && begin() == end()
+	       && this->_M_impl._M_header._M_left == _M_end()
+	       && this->_M_impl._M_header._M_right == _M_end();
+
+      unsigned int __len = _Rb_tree_black_count(_M_leftmost(), _M_root());
+      for (const_iterator __it = begin(); __it != end(); ++__it)
+	{
+	  _Const_Link_type __x = static_cast<_Const_Link_type>(__it._M_node);
+	  _Const_Link_type __L = _S_left(__x);
+	  _Const_Link_type __R = _S_right(__x);
+
+	  if (__x->_M_color == _S_red)
+	    if ((__L && __L->_M_color == _S_red)
+		|| (__R && __R->_M_color == _S_red))
+	      return false;
+
+	  if (__L && _M_impl._M_key_compare(_S_key(__x), _S_key(__L)))
+	    return false;
+	  if (__R && _M_impl._M_key_compare(_S_key(__R), _S_key(__x)))
+	    return false;
+
+	  if (!__L && !__R && _Rb_tree_black_count(__x, _M_root()) != __len)
+	    return false;
+	}
+
+      if (_M_leftmost() != _Rb_tree_node_base::_S_minimum(_M_root()))
+	return false;
+      if (_M_rightmost() != _Rb_tree_node_base::_S_maximum(_M_root()))
+	return false;
+      return true;
+    }
+
+#if __cplusplus > 201402L
+  // Allow access to internals of compatible _Rb_tree specializations.
+  template<typename _Key, typename _Val, typename _Sel, typename _Cmp1,
+	   typename _Alloc, typename _Cmp2>
+    struct _Rb_tree_merge_helper<_Rb_tree<_Key, _Val, _Sel, _Cmp1, _Alloc>,
+				 _Cmp2>
+    {
+    private:
+      friend class _Rb_tree<_Key, _Val, _Sel, _Cmp1, _Alloc>;
+
+      static auto&
+      _S_get_impl(_Rb_tree<_Key, _Val, _Sel, _Cmp2, _Alloc>& __tree)
+      { return __tree._M_impl; }
+    };
+#endif // C++17
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stl_tree.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stl_tree.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stl_uninitialized.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stl_uninitialized.h
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stl_uninitialized.h
@@ -0,0 +1,1146 @@
+// Raw memory manipulators -*- C++ -*-
+
+// Copyright (C) 2001-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/*
+ *
+ * Copyright (c) 1994
+ * Hewlett-Packard Company
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Hewlett-Packard Company makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ *
+ *
+ * Copyright (c) 1996,1997
+ * Silicon Graphics Computer Systems, Inc.
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Silicon Graphics makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ */
+
+/** @file bits/stl_uninitialized.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{memory}
+ */
+
+#ifndef _STL_UNINITIALIZED_H
+#define _STL_UNINITIALIZED_H 1
+
+#if __cplusplus >= 201103L
+#include <type_traits>
+#endif
+
+#include <bits/stl_algobase.h>    // copy
+#include <ext/alloc_traits.h>     // __alloc_traits
+
+#if __cplusplus >= 201703L
+#include <bits/stl_pair.h>
+#endif
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /** @addtogroup memory
+   *  @{
+   */
+
+  /// @cond undocumented
+
+#if __cplusplus >= 201103L
+  template<typename _ValueType, typename _Tp>
+    constexpr bool
+    __check_constructible()
+    {
+      // Trivial types can have deleted constructors, but std::copy etc.
+      // only use assignment (or memmove) not construction, so we need an
+      // explicit check that construction from _Tp is actually valid,
+      // otherwise some ill-formed uses of std::uninitialized_xxx would
+      // compile without errors. This gives a nice clear error message.
+      static_assert(is_constructible<_ValueType, _Tp>::value,
+	  "result type must be constructible from input type");
+
+      return true;
+    }
+
+// If the type is trivial we don't need to construct it, just assign to it.
+// But trivial types can still have deleted or inaccessible assignment,
+// so don't try to use std::copy or std::fill etc. if we can't assign.
+# define _GLIBCXX_USE_ASSIGN_FOR_INIT(T, U) \
+    __is_trivial(T) && __is_assignable(T&, U) \
+    && std::__check_constructible<T, U>()
+#else
+// No need to check if is_constructible<T, U> for C++98. Trivial types have
+// no user-declared constructors, so if the assignment is valid, construction
+// should be too.
+# define _GLIBCXX_USE_ASSIGN_FOR_INIT(T, U) \
+    __is_trivial(T) && __is_assignable(T&, U)
+#endif
+
+  template<typename _InputIterator, typename _ForwardIterator>
+    _GLIBCXX20_CONSTEXPR
+    _ForwardIterator
+    __do_uninit_copy(_InputIterator __first, _InputIterator __last,
+		     _ForwardIterator __result)
+    {
+      _ForwardIterator __cur = __result;
+      __try
+	{
+	  for (; __first != __last; ++__first, (void)++__cur)
+	    std::_Construct(std::__addressof(*__cur), *__first);
+	  return __cur;
+	}
+      __catch(...)
+	{
+	  std::_Destroy(__result, __cur);
+	  __throw_exception_again;
+	}
+    }
+
+  template<bool _TrivialValueTypes>
+    struct __uninitialized_copy
+    {
+      template<typename _InputIterator, typename _ForwardIterator>
+        static _ForwardIterator
+        __uninit_copy(_InputIterator __first, _InputIterator __last,
+		      _ForwardIterator __result)
+	{ return std::__do_uninit_copy(__first, __last, __result); }
+    };
+
+  template<>
+    struct __uninitialized_copy<true>
+    {
+      template<typename _InputIterator, typename _ForwardIterator>
+        static _ForwardIterator
+        __uninit_copy(_InputIterator __first, _InputIterator __last,
+		      _ForwardIterator __result)
+        { return std::copy(__first, __last, __result); }
+    };
+
+  /// @endcond
+
+  /**
+   *  @brief Copies the range [first,last) into result.
+   *  @param  __first  An input iterator.
+   *  @param  __last   An input iterator.
+   *  @param  __result An output iterator.
+   *  @return   __result + (__first - __last)
+   *
+   *  Like copy(), but does not require an initialized output range.
+  */
+  template<typename _InputIterator, typename _ForwardIterator>
+    inline _ForwardIterator
+    uninitialized_copy(_InputIterator __first, _InputIterator __last,
+		       _ForwardIterator __result)
+    {
+      typedef typename iterator_traits<_InputIterator>::value_type
+	_ValueType1;
+      typedef typename iterator_traits<_ForwardIterator>::value_type
+	_ValueType2;
+
+      // _ValueType1 must be trivially-copyable to use memmove, so don't
+      // bother optimizing to std::copy if it isn't.
+      // XXX Unnecessary because std::copy would check it anyway?
+      const bool __can_memmove = __is_trivial(_ValueType1);
+
+#if __cplusplus < 201103L
+      typedef typename iterator_traits<_InputIterator>::reference _From;
+#else
+      using _From = decltype(*__first);
+#endif
+      const bool __assignable
+	= _GLIBCXX_USE_ASSIGN_FOR_INIT(_ValueType2, _From);
+
+      return std::__uninitialized_copy<__can_memmove && __assignable>::
+	__uninit_copy(__first, __last, __result);
+    }
+
+  /// @cond undocumented
+
+  template<typename _ForwardIterator, typename _Tp>
+    _GLIBCXX20_CONSTEXPR void
+    __do_uninit_fill(_ForwardIterator __first, _ForwardIterator __last,
+		     const _Tp& __x)
+    {
+      _ForwardIterator __cur = __first;
+      __try
+	{
+	  for (; __cur != __last; ++__cur)
+	    std::_Construct(std::__addressof(*__cur), __x);
+	}
+      __catch(...)
+	{
+	  std::_Destroy(__first, __cur);
+	  __throw_exception_again;
+	}
+    }
+
+  template<bool _TrivialValueType>
+    struct __uninitialized_fill
+    {
+      template<typename _ForwardIterator, typename _Tp>
+        static void
+        __uninit_fill(_ForwardIterator __first, _ForwardIterator __last,
+		      const _Tp& __x)
+	{ std::__do_uninit_fill(__first, __last, __x); }
+    };
+
+  template<>
+    struct __uninitialized_fill<true>
+    {
+      template<typename _ForwardIterator, typename _Tp>
+        static void
+        __uninit_fill(_ForwardIterator __first, _ForwardIterator __last,
+		      const _Tp& __x)
+        { std::fill(__first, __last, __x); }
+    };
+
+  /// @endcond
+
+  /**
+   *  @brief Copies the value x into the range [first,last).
+   *  @param  __first  An input iterator.
+   *  @param  __last   An input iterator.
+   *  @param  __x      The source value.
+   *  @return   Nothing.
+   *
+   *  Like fill(), but does not require an initialized output range.
+  */
+  template<typename _ForwardIterator, typename _Tp>
+    inline void
+    uninitialized_fill(_ForwardIterator __first, _ForwardIterator __last,
+		       const _Tp& __x)
+    {
+      typedef typename iterator_traits<_ForwardIterator>::value_type
+	_ValueType;
+
+      // Trivial types do not need a constructor to begin their lifetime,
+      // so try to use std::fill to benefit from its memset optimization.
+      const bool __can_fill
+	= _GLIBCXX_USE_ASSIGN_FOR_INIT(_ValueType, const _Tp&);
+
+      std::__uninitialized_fill<__can_fill>::
+	__uninit_fill(__first, __last, __x);
+    }
+
+  /// @cond undocumented
+
+  template<typename _ForwardIterator, typename _Size, typename _Tp>
+    _GLIBCXX20_CONSTEXPR
+    _ForwardIterator
+    __do_uninit_fill_n(_ForwardIterator __first, _Size __n, const _Tp& __x)
+    {
+      _ForwardIterator __cur = __first;
+      __try
+	{
+	  for (; __n > 0; --__n, (void) ++__cur)
+	    std::_Construct(std::__addressof(*__cur), __x);
+	  return __cur;
+	}
+      __catch(...)
+	{
+	  std::_Destroy(__first, __cur);
+	  __throw_exception_again;
+	}
+    }
+
+  template<bool _TrivialValueType>
+    struct __uninitialized_fill_n
+    {
+      template<typename _ForwardIterator, typename _Size, typename _Tp>
+	static _ForwardIterator
+        __uninit_fill_n(_ForwardIterator __first, _Size __n,
+			const _Tp& __x)
+	{ return std::__do_uninit_fill_n(__first, __n, __x); }
+    };
+
+  template<>
+    struct __uninitialized_fill_n<true>
+    {
+      template<typename _ForwardIterator, typename _Size, typename _Tp>
+	static _ForwardIterator
+        __uninit_fill_n(_ForwardIterator __first, _Size __n,
+			const _Tp& __x)
+        { return std::fill_n(__first, __n, __x); }
+    };
+
+  /// @endcond
+
+   // _GLIBCXX_RESOLVE_LIB_DEFECTS
+   // DR 1339. uninitialized_fill_n should return the end of its range
+  /**
+   *  @brief Copies the value x into the range [first,first+n).
+   *  @param  __first  An input iterator.
+   *  @param  __n      The number of copies to make.
+   *  @param  __x      The source value.
+   *  @return   Nothing.
+   *
+   *  Like fill_n(), but does not require an initialized output range.
+  */
+  template<typename _ForwardIterator, typename _Size, typename _Tp>
+    inline _ForwardIterator
+    uninitialized_fill_n(_ForwardIterator __first, _Size __n, const _Tp& __x)
+    {
+      typedef typename iterator_traits<_ForwardIterator>::value_type
+	_ValueType;
+
+      // Trivial types do not need a constructor to begin their lifetime,
+      // so try to use std::fill_n to benefit from its optimizations.
+      const bool __can_fill
+	= _GLIBCXX_USE_ASSIGN_FOR_INIT(_ValueType, const _Tp&)
+      // For arbitrary class types and floating point types we can't assume
+      // that __n > 0 and std::__size_to_integer(__n) > 0 are equivalent,
+      // so only use std::fill_n when _Size is already an integral type.
+	&& __is_integer<_Size>::__value;
+
+      return __uninitialized_fill_n<__can_fill>::
+	__uninit_fill_n(__first, __n, __x);
+    }
+
+#undef _GLIBCXX_USE_ASSIGN_FOR_INIT
+
+  /// @cond undocumented
+
+  // Extensions: versions of uninitialized_copy, uninitialized_fill,
+  //  and uninitialized_fill_n that take an allocator parameter.
+  //  We dispatch back to the standard versions when we're given the
+  //  default allocator.  For nondefault allocators we do not use
+  //  any of the POD optimizations.
+
+  template<typename _InputIterator, typename _ForwardIterator,
+	   typename _Allocator>
+    _GLIBCXX20_CONSTEXPR
+    _ForwardIterator
+    __uninitialized_copy_a(_InputIterator __first, _InputIterator __last,
+			   _ForwardIterator __result, _Allocator& __alloc)
+    {
+      _ForwardIterator __cur = __result;
+      __try
+	{
+	  typedef __gnu_cxx::__alloc_traits<_Allocator> __traits;
+	  for (; __first != __last; ++__first, (void)++__cur)
+	    __traits::construct(__alloc, std::__addressof(*__cur), *__first);
+	  return __cur;
+	}
+      __catch(...)
+	{
+	  std::_Destroy(__result, __cur, __alloc);
+	  __throw_exception_again;
+	}
+    }
+
+  template<typename _InputIterator, typename _ForwardIterator, typename _Tp>
+    _GLIBCXX20_CONSTEXPR
+    inline _ForwardIterator
+    __uninitialized_copy_a(_InputIterator __first, _InputIterator __last,
+			   _ForwardIterator __result, allocator<_Tp>&)
+    {
+#ifdef __cpp_lib_is_constant_evaluated
+      if (std::is_constant_evaluated())
+	return std::__do_uninit_copy(__first, __last, __result);
+#endif
+      return std::uninitialized_copy(__first, __last, __result);
+    }
+
+  template<typename _InputIterator, typename _ForwardIterator,
+	   typename _Allocator>
+    _GLIBCXX20_CONSTEXPR
+    inline _ForwardIterator
+    __uninitialized_move_a(_InputIterator __first, _InputIterator __last,
+			   _ForwardIterator __result, _Allocator& __alloc)
+    {
+      return std::__uninitialized_copy_a(_GLIBCXX_MAKE_MOVE_ITERATOR(__first),
+					 _GLIBCXX_MAKE_MOVE_ITERATOR(__last),
+					 __result, __alloc);
+    }
+
+  template<typename _InputIterator, typename _ForwardIterator,
+	   typename _Allocator>
+    _GLIBCXX20_CONSTEXPR
+    inline _ForwardIterator
+    __uninitialized_move_if_noexcept_a(_InputIterator __first,
+				       _InputIterator __last,
+				       _ForwardIterator __result,
+				       _Allocator& __alloc)
+    {
+      return std::__uninitialized_copy_a
+	(_GLIBCXX_MAKE_MOVE_IF_NOEXCEPT_ITERATOR(__first),
+	 _GLIBCXX_MAKE_MOVE_IF_NOEXCEPT_ITERATOR(__last), __result, __alloc);
+    }
+
+  template<typename _ForwardIterator, typename _Tp, typename _Allocator>
+    _GLIBCXX20_CONSTEXPR
+    void
+    __uninitialized_fill_a(_ForwardIterator __first, _ForwardIterator __last,
+			   const _Tp& __x, _Allocator& __alloc)
+    {
+      _ForwardIterator __cur = __first;
+      __try
+	{
+	  typedef __gnu_cxx::__alloc_traits<_Allocator> __traits;
+	  for (; __cur != __last; ++__cur)
+	    __traits::construct(__alloc, std::__addressof(*__cur), __x);
+	}
+      __catch(...)
+	{
+	  std::_Destroy(__first, __cur, __alloc);
+	  __throw_exception_again;
+	}
+    }
+
+  template<typename _ForwardIterator, typename _Tp, typename _Tp2>
+    _GLIBCXX20_CONSTEXPR
+    inline void
+    __uninitialized_fill_a(_ForwardIterator __first, _ForwardIterator __last,
+			   const _Tp& __x, allocator<_Tp2>&)
+    {
+#ifdef __cpp_lib_is_constant_evaluated
+      if (std::is_constant_evaluated())
+	return std::__do_uninit_fill(__first, __last, __x);
+#endif
+      std::uninitialized_fill(__first, __last, __x);
+    }
+
+  template<typename _ForwardIterator, typename _Size, typename _Tp,
+	   typename _Allocator>
+     _GLIBCXX20_CONSTEXPR
+    _ForwardIterator
+    __uninitialized_fill_n_a(_ForwardIterator __first, _Size __n,
+			     const _Tp& __x, _Allocator& __alloc)
+    {
+      _ForwardIterator __cur = __first;
+      __try
+	{
+	  typedef __gnu_cxx::__alloc_traits<_Allocator> __traits;
+	  for (; __n > 0; --__n, (void) ++__cur)
+	    __traits::construct(__alloc, std::__addressof(*__cur), __x);
+	  return __cur;
+	}
+      __catch(...)
+	{
+	  std::_Destroy(__first, __cur, __alloc);
+	  __throw_exception_again;
+	}
+    }
+
+  template<typename _ForwardIterator, typename _Size, typename _Tp,
+	   typename _Tp2>
+    _GLIBCXX20_CONSTEXPR
+    inline _ForwardIterator
+    __uninitialized_fill_n_a(_ForwardIterator __first, _Size __n,
+			     const _Tp& __x, allocator<_Tp2>&)
+    {
+#ifdef __cpp_lib_is_constant_evaluated
+      if (std::is_constant_evaluated())
+	return std::__do_uninit_fill_n(__first, __n, __x);
+#endif
+      return std::uninitialized_fill_n(__first, __n, __x);
+    }
+
+
+  // Extensions: __uninitialized_copy_move, __uninitialized_move_copy,
+  // __uninitialized_fill_move, __uninitialized_move_fill.
+  // All of these algorithms take a user-supplied allocator, which is used
+  // for construction and destruction.
+
+  // __uninitialized_copy_move
+  // Copies [first1, last1) into [result, result + (last1 - first1)), and
+  //  move [first2, last2) into
+  //  [result, result + (last1 - first1) + (last2 - first2)).
+  template<typename _InputIterator1, typename _InputIterator2,
+	   typename _ForwardIterator, typename _Allocator>
+    inline _ForwardIterator
+    __uninitialized_copy_move(_InputIterator1 __first1,
+			      _InputIterator1 __last1,
+			      _InputIterator2 __first2,
+			      _InputIterator2 __last2,
+			      _ForwardIterator __result,
+			      _Allocator& __alloc)
+    {
+      _ForwardIterator __mid = std::__uninitialized_copy_a(__first1, __last1,
+							   __result,
+							   __alloc);
+      __try
+	{
+	  return std::__uninitialized_move_a(__first2, __last2, __mid, __alloc);
+	}
+      __catch(...)
+	{
+	  std::_Destroy(__result, __mid, __alloc);
+	  __throw_exception_again;
+	}
+    }
+
+  // __uninitialized_move_copy
+  // Moves [first1, last1) into [result, result + (last1 - first1)), and
+  //  copies [first2, last2) into
+  //  [result, result + (last1 - first1) + (last2 - first2)).
+  template<typename _InputIterator1, typename _InputIterator2,
+	   typename _ForwardIterator, typename _Allocator>
+    inline _ForwardIterator
+    __uninitialized_move_copy(_InputIterator1 __first1,
+			      _InputIterator1 __last1,
+			      _InputIterator2 __first2,
+			      _InputIterator2 __last2,
+			      _ForwardIterator __result,
+			      _Allocator& __alloc)
+    {
+      _ForwardIterator __mid = std::__uninitialized_move_a(__first1, __last1,
+							   __result,
+							   __alloc);
+      __try
+	{
+	  return std::__uninitialized_copy_a(__first2, __last2, __mid, __alloc);
+	}
+      __catch(...)
+	{
+	  std::_Destroy(__result, __mid, __alloc);
+	  __throw_exception_again;
+	}
+    }
+
+  // __uninitialized_fill_move
+  // Fills [result, mid) with x, and moves [first, last) into
+  //  [mid, mid + (last - first)).
+  template<typename _ForwardIterator, typename _Tp, typename _InputIterator,
+	   typename _Allocator>
+    inline _ForwardIterator
+    __uninitialized_fill_move(_ForwardIterator __result, _ForwardIterator __mid,
+			      const _Tp& __x, _InputIterator __first,
+			      _InputIterator __last, _Allocator& __alloc)
+    {
+      std::__uninitialized_fill_a(__result, __mid, __x, __alloc);
+      __try
+	{
+	  return std::__uninitialized_move_a(__first, __last, __mid, __alloc);
+	}
+      __catch(...)
+	{
+	  std::_Destroy(__result, __mid, __alloc);
+	  __throw_exception_again;
+	}
+    }
+
+  // __uninitialized_move_fill
+  // Moves [first1, last1) into [first2, first2 + (last1 - first1)), and
+  //  fills [first2 + (last1 - first1), last2) with x.
+  template<typename _InputIterator, typename _ForwardIterator, typename _Tp,
+	   typename _Allocator>
+    inline void
+    __uninitialized_move_fill(_InputIterator __first1, _InputIterator __last1,
+			      _ForwardIterator __first2,
+			      _ForwardIterator __last2, const _Tp& __x,
+			      _Allocator& __alloc)
+    {
+      _ForwardIterator __mid2 = std::__uninitialized_move_a(__first1, __last1,
+							    __first2,
+							    __alloc);
+      __try
+	{
+	  std::__uninitialized_fill_a(__mid2, __last2, __x, __alloc);
+	}
+      __catch(...)
+	{
+	  std::_Destroy(__first2, __mid2, __alloc);
+	  __throw_exception_again;
+	}
+    }
+
+  /// @endcond
+
+#if __cplusplus >= 201103L
+  /// @cond undocumented
+
+  // Extensions: __uninitialized_default, __uninitialized_default_n,
+  // __uninitialized_default_a, __uninitialized_default_n_a.
+
+  template<bool _TrivialValueType>
+    struct __uninitialized_default_1
+    {
+      template<typename _ForwardIterator>
+        static void
+        __uninit_default(_ForwardIterator __first, _ForwardIterator __last)
+        {
+	  _ForwardIterator __cur = __first;
+	  __try
+	    {
+	      for (; __cur != __last; ++__cur)
+		std::_Construct(std::__addressof(*__cur));
+	    }
+	  __catch(...)
+	    {
+	      std::_Destroy(__first, __cur);
+	      __throw_exception_again;
+	    }
+	}
+    };
+
+  template<>
+    struct __uninitialized_default_1<true>
+    {
+      template<typename _ForwardIterator>
+        static void
+        __uninit_default(_ForwardIterator __first, _ForwardIterator __last)
+        {
+	  if (__first == __last)
+	    return;
+
+	  typename iterator_traits<_ForwardIterator>::value_type* __val
+	    = std::__addressof(*__first);
+	  std::_Construct(__val);
+	  if (++__first != __last)
+	    std::fill(__first, __last, *__val);
+	}
+    };
+
+  template<bool _TrivialValueType>
+    struct __uninitialized_default_n_1
+    {
+      template<typename _ForwardIterator, typename _Size>
+	_GLIBCXX20_CONSTEXPR
+        static _ForwardIterator
+        __uninit_default_n(_ForwardIterator __first, _Size __n)
+        {
+	  _ForwardIterator __cur = __first;
+	  __try
+	    {
+	      for (; __n > 0; --__n, (void) ++__cur)
+		std::_Construct(std::__addressof(*__cur));
+	      return __cur;
+	    }
+	  __catch(...)
+	    {
+	      std::_Destroy(__first, __cur);
+	      __throw_exception_again;
+	    }
+	}
+    };
+
+  template<>
+    struct __uninitialized_default_n_1<true>
+    {
+      template<typename _ForwardIterator, typename _Size>
+	_GLIBCXX20_CONSTEXPR
+        static _ForwardIterator
+        __uninit_default_n(_ForwardIterator __first, _Size __n)
+        {
+	  if (__n > 0)
+	    {
+	      typename iterator_traits<_ForwardIterator>::value_type* __val
+		= std::__addressof(*__first);
+	      std::_Construct(__val);
+	      ++__first;
+	      __first = std::fill_n(__first, __n - 1, *__val);
+	    }
+	  return __first;
+	}
+    };
+
+  // __uninitialized_default
+  // Fills [first, last) with value-initialized value_types.
+  template<typename _ForwardIterator>
+    inline void
+    __uninitialized_default(_ForwardIterator __first,
+			    _ForwardIterator __last)
+    {
+      typedef typename iterator_traits<_ForwardIterator>::value_type
+	_ValueType;
+      // trivial types can have deleted assignment
+      const bool __assignable = is_copy_assignable<_ValueType>::value;
+
+      std::__uninitialized_default_1<__is_trivial(_ValueType)
+				     && __assignable>::
+	__uninit_default(__first, __last);
+    }
+
+  // __uninitialized_default_n
+  // Fills [first, first + n) with value-initialized value_types.
+  template<typename _ForwardIterator, typename _Size>
+    _GLIBCXX20_CONSTEXPR
+    inline _ForwardIterator
+    __uninitialized_default_n(_ForwardIterator __first, _Size __n)
+    {
+      typedef typename iterator_traits<_ForwardIterator>::value_type
+	_ValueType;
+      // See uninitialized_fill_n for the conditions for using std::fill_n.
+      constexpr bool __can_fill
+	= __and_<is_integral<_Size>, is_copy_assignable<_ValueType>>::value;
+
+      return __uninitialized_default_n_1<__is_trivial(_ValueType)
+					 && __can_fill>::
+	__uninit_default_n(__first, __n);
+    }
+
+
+  // __uninitialized_default_a
+  // Fills [first, last) with value_types constructed by the allocator
+  // alloc, with no arguments passed to the construct call.
+  template<typename _ForwardIterator, typename _Allocator>
+    void
+    __uninitialized_default_a(_ForwardIterator __first,
+			      _ForwardIterator __last,
+			      _Allocator& __alloc)
+    {
+      _ForwardIterator __cur = __first;
+      __try
+	{
+	  typedef __gnu_cxx::__alloc_traits<_Allocator> __traits;
+	  for (; __cur != __last; ++__cur)
+	    __traits::construct(__alloc, std::__addressof(*__cur));
+	}
+      __catch(...)
+	{
+	  std::_Destroy(__first, __cur, __alloc);
+	  __throw_exception_again;
+	}
+    }
+
+  template<typename _ForwardIterator, typename _Tp>
+    inline void
+    __uninitialized_default_a(_ForwardIterator __first,
+			      _ForwardIterator __last,
+			      allocator<_Tp>&)
+    { std::__uninitialized_default(__first, __last); }
+
+
+  // __uninitialized_default_n_a
+  // Fills [first, first + n) with value_types constructed by the allocator
+  // alloc, with no arguments passed to the construct call.
+  template<typename _ForwardIterator, typename _Size, typename _Allocator>
+    _GLIBCXX20_CONSTEXPR _ForwardIterator
+    __uninitialized_default_n_a(_ForwardIterator __first, _Size __n,
+				_Allocator& __alloc)
+    {
+      _ForwardIterator __cur = __first;
+      __try
+	{
+	  typedef __gnu_cxx::__alloc_traits<_Allocator> __traits;
+	  for (; __n > 0; --__n, (void) ++__cur)
+	    __traits::construct(__alloc, std::__addressof(*__cur));
+	  return __cur;
+	}
+      __catch(...)
+	{
+	  std::_Destroy(__first, __cur, __alloc);
+	  __throw_exception_again;
+	}
+    }
+
+  // __uninitialized_default_n_a specialization for std::allocator,
+  // which ignores the allocator and value-initializes the elements.
+  template<typename _ForwardIterator, typename _Size, typename _Tp>
+    _GLIBCXX20_CONSTEXPR
+    inline _ForwardIterator
+    __uninitialized_default_n_a(_ForwardIterator __first, _Size __n,
+				allocator<_Tp>&)
+    { return std::__uninitialized_default_n(__first, __n); }
+
+  template<bool _TrivialValueType>
+    struct __uninitialized_default_novalue_1
+    {
+      template<typename _ForwardIterator>
+	static void
+	__uninit_default_novalue(_ForwardIterator __first,
+				 _ForwardIterator __last)
+	{
+	  _ForwardIterator __cur = __first;
+	  __try
+	    {
+	      for (; __cur != __last; ++__cur)
+		std::_Construct_novalue(std::__addressof(*__cur));
+	    }
+	  __catch(...)
+	    {
+	      std::_Destroy(__first, __cur);
+	      __throw_exception_again;
+	    }
+	}
+    };
+
+  template<>
+    struct __uninitialized_default_novalue_1<true>
+    {
+      template<typename _ForwardIterator>
+        static void
+        __uninit_default_novalue(_ForwardIterator __first,
+				 _ForwardIterator __last)
+	{
+	}
+    };
+
+  template<bool _TrivialValueType>
+    struct __uninitialized_default_novalue_n_1
+    {
+      template<typename _ForwardIterator, typename _Size>
+	static _ForwardIterator
+	__uninit_default_novalue_n(_ForwardIterator __first, _Size __n)
+	{
+	  _ForwardIterator __cur = __first;
+	  __try
+	    {
+	      for (; __n > 0; --__n, (void) ++__cur)
+		std::_Construct_novalue(std::__addressof(*__cur));
+	      return __cur;
+	    }
+	  __catch(...)
+	    {
+	      std::_Destroy(__first, __cur);
+	      __throw_exception_again;
+	    }
+	}
+    };
+
+  template<>
+    struct __uninitialized_default_novalue_n_1<true>
+    {
+      template<typename _ForwardIterator, typename _Size>
+	static _ForwardIterator
+	__uninit_default_novalue_n(_ForwardIterator __first, _Size __n)
+	{ return std::next(__first, __n); }
+    };
+
+  // __uninitialized_default_novalue
+  // Fills [first, last) with default-initialized value_types.
+  template<typename _ForwardIterator>
+    inline void
+    __uninitialized_default_novalue(_ForwardIterator __first,
+				    _ForwardIterator __last)
+    {
+      typedef typename iterator_traits<_ForwardIterator>::value_type
+	_ValueType;
+
+      std::__uninitialized_default_novalue_1<
+	is_trivially_default_constructible<_ValueType>::value>::
+	__uninit_default_novalue(__first, __last);
+    }
+
+  // __uninitialized_default_novalue_n
+  // Fills [first, first + n) with default-initialized value_types.
+  template<typename _ForwardIterator, typename _Size>
+    inline _ForwardIterator
+    __uninitialized_default_novalue_n(_ForwardIterator __first, _Size __n)
+    {
+      typedef typename iterator_traits<_ForwardIterator>::value_type
+	_ValueType;
+
+      return __uninitialized_default_novalue_n_1<
+	is_trivially_default_constructible<_ValueType>::value>::
+	__uninit_default_novalue_n(__first, __n);
+    }
+
+  template<typename _InputIterator, typename _Size,
+	   typename _ForwardIterator>
+    _ForwardIterator
+    __uninitialized_copy_n(_InputIterator __first, _Size __n,
+			   _ForwardIterator __result, input_iterator_tag)
+    {
+      _ForwardIterator __cur = __result;
+      __try
+	{
+	  for (; __n > 0; --__n, (void) ++__first, ++__cur)
+	    std::_Construct(std::__addressof(*__cur), *__first);
+	  return __cur;
+	}
+      __catch(...)
+	{
+	  std::_Destroy(__result, __cur);
+	  __throw_exception_again;
+	}
+    }
+
+  template<typename _RandomAccessIterator, typename _Size,
+	   typename _ForwardIterator>
+    inline _ForwardIterator
+    __uninitialized_copy_n(_RandomAccessIterator __first, _Size __n,
+			   _ForwardIterator __result,
+			   random_access_iterator_tag)
+    { return std::uninitialized_copy(__first, __first + __n, __result); }
+
+  template<typename _InputIterator, typename _Size,
+	   typename _ForwardIterator>
+    pair<_InputIterator, _ForwardIterator>
+    __uninitialized_copy_n_pair(_InputIterator __first, _Size __n,
+			   _ForwardIterator __result, input_iterator_tag)
+    {
+      _ForwardIterator __cur = __result;
+      __try
+	{
+	  for (; __n > 0; --__n, (void) ++__first, ++__cur)
+	    std::_Construct(std::__addressof(*__cur), *__first);
+	  return {__first, __cur};
+	}
+      __catch(...)
+	{
+	  std::_Destroy(__result, __cur);
+	  __throw_exception_again;
+	}
+    }
+
+  template<typename _RandomAccessIterator, typename _Size,
+	   typename _ForwardIterator>
+    inline pair<_RandomAccessIterator, _ForwardIterator>
+    __uninitialized_copy_n_pair(_RandomAccessIterator __first, _Size __n,
+			   _ForwardIterator __result,
+			   random_access_iterator_tag)
+    {
+      auto __second_res = uninitialized_copy(__first, __first + __n, __result);
+      auto __first_res = std::next(__first, __n);
+      return {__first_res, __second_res};
+    }
+
+  /// @endcond
+
+  /**
+   *  @brief Copies the range [first,first+n) into result.
+   *  @param  __first  An input iterator.
+   *  @param  __n      The number of elements to copy.
+   *  @param  __result An output iterator.
+   *  @return  __result + __n
+   *  @since C++11
+   *
+   *  Like copy_n(), but does not require an initialized output range.
+  */
+  template<typename _InputIterator, typename _Size, typename _ForwardIterator>
+    inline _ForwardIterator
+    uninitialized_copy_n(_InputIterator __first, _Size __n,
+			 _ForwardIterator __result)
+    { return std::__uninitialized_copy_n(__first, __n, __result,
+					 std::__iterator_category(__first)); }
+
+  /// @cond undocumented
+  template<typename _InputIterator, typename _Size, typename _ForwardIterator>
+    inline pair<_InputIterator, _ForwardIterator>
+    __uninitialized_copy_n_pair(_InputIterator __first, _Size __n,
+			      _ForwardIterator __result)
+    {
+      return
+	std::__uninitialized_copy_n_pair(__first, __n, __result,
+					 std::__iterator_category(__first));
+    }
+  /// @endcond
+#endif
+
+#if __cplusplus >= 201703L
+# define __cpp_lib_raw_memory_algorithms 201606L
+
+  /**
+   *  @brief Default-initializes objects in the range [first,last).
+   *  @param  __first  A forward iterator.
+   *  @param  __last   A forward iterator.
+   *  @since C++17
+  */
+  template <typename _ForwardIterator>
+    inline void
+    uninitialized_default_construct(_ForwardIterator __first,
+				    _ForwardIterator __last)
+    {
+      __uninitialized_default_novalue(__first, __last);
+    }
+
+  /**
+   *  @brief Default-initializes objects in the range [first,first+count).
+   *  @param  __first  A forward iterator.
+   *  @param  __count  The number of objects to construct.
+   *  @return   __first + __count
+   *  @since C++17
+  */
+  template <typename _ForwardIterator, typename _Size>
+    inline _ForwardIterator
+    uninitialized_default_construct_n(_ForwardIterator __first, _Size __count)
+    {
+      return __uninitialized_default_novalue_n(__first, __count);
+    }
+
+  /**
+   *  @brief Value-initializes objects in the range [first,last).
+   *  @param  __first  A forward iterator.
+   *  @param  __last   A forward iterator.
+   *  @since C++17
+  */
+  template <typename _ForwardIterator>
+    inline void
+    uninitialized_value_construct(_ForwardIterator __first,
+				  _ForwardIterator __last)
+    {
+      return __uninitialized_default(__first, __last);
+    }
+
+  /**
+   *  @brief Value-initializes objects in the range [first,first+count).
+   *  @param  __first  A forward iterator.
+   *  @param  __count  The number of objects to construct.
+   *  @return   __result + __count
+   *  @since C++17
+  */
+  template <typename _ForwardIterator, typename _Size>
+    inline _ForwardIterator
+    uninitialized_value_construct_n(_ForwardIterator __first, _Size __count)
+    {
+      return __uninitialized_default_n(__first, __count);
+    }
+
+  /**
+   *  @brief Move-construct from the range [first,last) into result.
+   *  @param  __first  An input iterator.
+   *  @param  __last   An input iterator.
+   *  @param  __result An output iterator.
+   *  @return   __result + (__first - __last)
+   *  @since C++17
+  */
+  template <typename _InputIterator, typename _ForwardIterator>
+    inline _ForwardIterator
+    uninitialized_move(_InputIterator __first, _InputIterator __last,
+		       _ForwardIterator __result)
+    {
+      return std::uninitialized_copy
+	(_GLIBCXX_MAKE_MOVE_ITERATOR(__first),
+	 _GLIBCXX_MAKE_MOVE_ITERATOR(__last), __result);
+    }
+
+  /**
+   *  @brief Move-construct from the range [first,first+count) into result.
+   *  @param  __first  An input iterator.
+   *  @param  __count  The number of objects to initialize.
+   *  @param  __result An output iterator.
+   *  @return  __result + __count
+   *  @since C++17
+  */
+  template <typename _InputIterator, typename _Size, typename _ForwardIterator>
+    inline pair<_InputIterator, _ForwardIterator>
+    uninitialized_move_n(_InputIterator __first, _Size __count,
+			 _ForwardIterator __result)
+    {
+      auto __res = std::__uninitialized_copy_n_pair
+	(_GLIBCXX_MAKE_MOVE_ITERATOR(__first),
+	 __count, __result);
+      return {__res.first.base(), __res.second};
+    }
+#endif // C++17
+
+#if __cplusplus >= 201103L
+  /// @cond undocumented
+
+  template<typename _Tp, typename _Up, typename _Allocator>
+    _GLIBCXX20_CONSTEXPR
+    inline void
+    __relocate_object_a(_Tp* __restrict __dest, _Up* __restrict __orig,
+			_Allocator& __alloc)
+    noexcept(noexcept(std::allocator_traits<_Allocator>::construct(__alloc,
+			 __dest, std::move(*__orig)))
+	     && noexcept(std::allocator_traits<_Allocator>::destroy(
+			    __alloc, std::__addressof(*__orig))))
+    {
+      typedef std::allocator_traits<_Allocator> __traits;
+      __traits::construct(__alloc, __dest, std::move(*__orig));
+      __traits::destroy(__alloc, std::__addressof(*__orig));
+    }
+
+  // This class may be specialized for specific types.
+  // Also known as is_trivially_relocatable.
+  template<typename _Tp, typename = void>
+    struct __is_bitwise_relocatable
+    : is_trivial<_Tp> { };
+
+  template <typename _InputIterator, typename _ForwardIterator,
+	    typename _Allocator>
+    _GLIBCXX20_CONSTEXPR
+    inline _ForwardIterator
+    __relocate_a_1(_InputIterator __first, _InputIterator __last,
+		   _ForwardIterator __result, _Allocator& __alloc)
+    noexcept(noexcept(std::__relocate_object_a(std::addressof(*__result),
+					       std::addressof(*__first),
+					       __alloc)))
+    {
+      typedef typename iterator_traits<_InputIterator>::value_type
+	_ValueType;
+      typedef typename iterator_traits<_ForwardIterator>::value_type
+	_ValueType2;
+      static_assert(std::is_same<_ValueType, _ValueType2>::value,
+	  "relocation is only possible for values of the same type");
+      _ForwardIterator __cur = __result;
+      for (; __first != __last; ++__first, (void)++__cur)
+	std::__relocate_object_a(std::__addressof(*__cur),
+				 std::__addressof(*__first), __alloc);
+      return __cur;
+    }
+
+  template <typename _Tp, typename _Up>
+    _GLIBCXX20_CONSTEXPR
+    inline __enable_if_t<std::__is_bitwise_relocatable<_Tp>::value, _Tp*>
+    __relocate_a_1(_Tp* __first, _Tp* __last,
+		   _Tp* __result,
+		   [[__maybe_unused__]] allocator<_Up>& __alloc) noexcept
+    {
+      ptrdiff_t __count = __last - __first;
+      if (__count > 0)
+	{
+#ifdef __cpp_lib_is_constant_evaluated
+	  if (std::is_constant_evaluated())
+	    {
+	      // Can't use memmove. Wrap the pointer so that __relocate_a_1
+	      // resolves to the non-trivial overload above.
+	      __gnu_cxx::__normal_iterator<_Tp*, void> __out(__result);
+	      __out = std::__relocate_a_1(__first, __last, __out, __alloc);
+	      return __out.base();
+	    }
+#endif
+	  __builtin_memmove(__result, __first, __count * sizeof(_Tp));
+	}
+      return __result + __count;
+    }
+
+
+  template <typename _InputIterator, typename _ForwardIterator,
+	    typename _Allocator>
+    _GLIBCXX20_CONSTEXPR
+    inline _ForwardIterator
+    __relocate_a(_InputIterator __first, _InputIterator __last,
+		 _ForwardIterator __result, _Allocator& __alloc)
+    noexcept(noexcept(__relocate_a_1(std::__niter_base(__first),
+				     std::__niter_base(__last),
+				     std::__niter_base(__result), __alloc)))
+    {
+      return std::__relocate_a_1(std::__niter_base(__first),
+				 std::__niter_base(__last),
+				 std::__niter_base(__result), __alloc);
+    }
+
+  /// @endcond
+#endif
+
+  /// @} group memory
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif /* _STL_UNINITIALIZED_H */
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@@ -0,0 +1,2130 @@
+// Vector implementation -*- C++ -*-
+
+// Copyright (C) 2001-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/*
+ *
+ * Copyright (c) 1994
+ * Hewlett-Packard Company
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Hewlett-Packard Company makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ *
+ *
+ * Copyright (c) 1996
+ * Silicon Graphics Computer Systems, Inc.
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Silicon Graphics makes no
+ * representations about the suitability of this  software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ */
+
+/** @file bits/stl_vector.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{vector}
+ */
+
+#ifndef _STL_VECTOR_H
+#define _STL_VECTOR_H 1
+
+#include <bits/stl_iterator_base_funcs.h>
+#include <bits/functexcept.h>
+#include <bits/concept_check.h>
+#if __cplusplus >= 201103L
+#include <initializer_list>
+#endif
+#if __cplusplus >= 202002L
+# include <compare>
+#define __cpp_lib_constexpr_vector 201907L
+#endif
+
+#include <debug/assertions.h>
+
+#if _GLIBCXX_SANITIZE_STD_ALLOCATOR && _GLIBCXX_SANITIZE_VECTOR
+extern "C" void
+__sanitizer_annotate_contiguous_container(const void*, const void*,
+					  const void*, const void*);
+#endif
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+_GLIBCXX_BEGIN_NAMESPACE_CONTAINER
+
+  /// See bits/stl_deque.h's _Deque_base for an explanation.
+  template<typename _Tp, typename _Alloc>
+    struct _Vector_base
+    {
+      typedef typename __gnu_cxx::__alloc_traits<_Alloc>::template
+	rebind<_Tp>::other _Tp_alloc_type;
+      typedef typename __gnu_cxx::__alloc_traits<_Tp_alloc_type>::pointer
+       	pointer;
+
+      struct _Vector_impl_data
+      {
+	pointer _M_start;
+	pointer _M_finish;
+	pointer _M_end_of_storage;
+
+	_GLIBCXX20_CONSTEXPR
+	_Vector_impl_data() _GLIBCXX_NOEXCEPT
+	: _M_start(), _M_finish(), _M_end_of_storage()
+	{ }
+
+#if __cplusplus >= 201103L
+	_GLIBCXX20_CONSTEXPR
+	_Vector_impl_data(_Vector_impl_data&& __x) noexcept
+	: _M_start(__x._M_start), _M_finish(__x._M_finish),
+	  _M_end_of_storage(__x._M_end_of_storage)
+	{ __x._M_start = __x._M_finish = __x._M_end_of_storage = pointer(); }
+#endif
+
+	_GLIBCXX20_CONSTEXPR
+	void
+	_M_copy_data(_Vector_impl_data const& __x) _GLIBCXX_NOEXCEPT
+	{
+	  _M_start = __x._M_start;
+	  _M_finish = __x._M_finish;
+	  _M_end_of_storage = __x._M_end_of_storage;
+	}
+
+	_GLIBCXX20_CONSTEXPR
+	void
+	_M_swap_data(_Vector_impl_data& __x) _GLIBCXX_NOEXCEPT
+	{
+	  // Do not use std::swap(_M_start, __x._M_start), etc as it loses
+	  // information used by TBAA.
+	  _Vector_impl_data __tmp;
+	  __tmp._M_copy_data(*this);
+	  _M_copy_data(__x);
+	  __x._M_copy_data(__tmp);
+	}
+      };
+
+      struct _Vector_impl
+	: public _Tp_alloc_type, public _Vector_impl_data
+      {
+	_GLIBCXX20_CONSTEXPR
+	_Vector_impl() _GLIBCXX_NOEXCEPT_IF(
+	    is_nothrow_default_constructible<_Tp_alloc_type>::value)
+	: _Tp_alloc_type()
+	{ }
+
+	_GLIBCXX20_CONSTEXPR
+	_Vector_impl(_Tp_alloc_type const& __a) _GLIBCXX_NOEXCEPT
+	: _Tp_alloc_type(__a)
+	{ }
+
+#if __cplusplus >= 201103L
+	// Not defaulted, to enforce noexcept(true) even when
+	// !is_nothrow_move_constructible<_Tp_alloc_type>.
+	_GLIBCXX20_CONSTEXPR
+	_Vector_impl(_Vector_impl&& __x) noexcept
+	: _Tp_alloc_type(std::move(__x)), _Vector_impl_data(std::move(__x))
+	{ }
+
+	_GLIBCXX20_CONSTEXPR
+	_Vector_impl(_Tp_alloc_type&& __a) noexcept
+	: _Tp_alloc_type(std::move(__a))
+	{ }
+
+	_GLIBCXX20_CONSTEXPR
+	_Vector_impl(_Tp_alloc_type&& __a, _Vector_impl&& __rv) noexcept
+	: _Tp_alloc_type(std::move(__a)), _Vector_impl_data(std::move(__rv))
+	{ }
+#endif
+
+#if _GLIBCXX_SANITIZE_STD_ALLOCATOR && _GLIBCXX_SANITIZE_VECTOR
+	template<typename = _Tp_alloc_type>
+	  struct _Asan
+	  {
+	    typedef typename __gnu_cxx::__alloc_traits<_Tp_alloc_type>
+	      ::size_type size_type;
+
+	    static _GLIBCXX20_CONSTEXPR void
+	    _S_shrink(_Vector_impl&, size_type) { }
+	    static _GLIBCXX20_CONSTEXPR void
+	    _S_on_dealloc(_Vector_impl&) { }
+
+	    typedef _Vector_impl& _Reinit;
+
+	    struct _Grow
+	    {
+	      _GLIBCXX20_CONSTEXPR _Grow(_Vector_impl&, size_type) { }
+	      _GLIBCXX20_CONSTEXPR void _M_grew(size_type) { }
+	    };
+	  };
+
+	// Enable ASan annotations for memory obtained from std::allocator.
+	template<typename _Up>
+	  struct _Asan<allocator<_Up> >
+	  {
+	    typedef typename __gnu_cxx::__alloc_traits<_Tp_alloc_type>
+	      ::size_type size_type;
+
+	    // Adjust ASan annotation for [_M_start, _M_end_of_storage) to
+	    // mark end of valid region as __curr instead of __prev.
+	    static _GLIBCXX20_CONSTEXPR void
+	    _S_adjust(_Vector_impl& __impl, pointer __prev, pointer __curr)
+	    {
+#if __cpp_lib_is_constant_evaluated
+	      if (std::is_constant_evaluated())
+		return;
+#endif
+	      __sanitizer_annotate_contiguous_container(__impl._M_start,
+		  __impl._M_end_of_storage, __prev, __curr);
+	    }
+
+	    static _GLIBCXX20_CONSTEXPR void
+	    _S_grow(_Vector_impl& __impl, size_type __n)
+	    { _S_adjust(__impl, __impl._M_finish, __impl._M_finish + __n); }
+
+	    static _GLIBCXX20_CONSTEXPR void
+	    _S_shrink(_Vector_impl& __impl, size_type __n)
+	    { _S_adjust(__impl, __impl._M_finish + __n, __impl._M_finish); }
+
+	    static _GLIBCXX20_CONSTEXPR void
+	    _S_on_dealloc(_Vector_impl& __impl)
+	    {
+	      if (__impl._M_start)
+		_S_adjust(__impl, __impl._M_finish, __impl._M_end_of_storage);
+	    }
+
+	    // Used on reallocation to tell ASan unused capacity is invalid.
+	    struct _Reinit
+	    {
+	      explicit _GLIBCXX20_CONSTEXPR
+	      _Reinit(_Vector_impl& __impl) : _M_impl(__impl)
+	      {
+		// Mark unused capacity as valid again before deallocating it.
+		_S_on_dealloc(_M_impl);
+	      }
+
+	      _GLIBCXX20_CONSTEXPR
+	      ~_Reinit()
+	      {
+		// Mark unused capacity as invalid after reallocation.
+		if (_M_impl._M_start)
+		  _S_adjust(_M_impl, _M_impl._M_end_of_storage,
+			    _M_impl._M_finish);
+	      }
+
+	      _Vector_impl& _M_impl;
+
+#if __cplusplus >= 201103L
+	      _Reinit(const _Reinit&) = delete;
+	      _Reinit& operator=(const _Reinit&) = delete;
+#endif
+	    };
+
+	    // Tell ASan when unused capacity is initialized to be valid.
+	    struct _Grow
+	    {
+	      _GLIBCXX20_CONSTEXPR
+	      _Grow(_Vector_impl& __impl, size_type __n)
+	      : _M_impl(__impl), _M_n(__n)
+	      { _S_grow(_M_impl, __n); }
+
+	      _GLIBCXX20_CONSTEXPR
+	      ~_Grow() { if (_M_n) _S_shrink(_M_impl, _M_n); }
+
+	      _GLIBCXX20_CONSTEXPR
+	      void _M_grew(size_type __n) { _M_n -= __n; }
+
+#if __cplusplus >= 201103L
+	      _Grow(const _Grow&) = delete;
+	      _Grow& operator=(const _Grow&) = delete;
+#endif
+	    private:
+	      _Vector_impl& _M_impl;
+	      size_type _M_n;
+	    };
+	  };
+
+#define _GLIBCXX_ASAN_ANNOTATE_REINIT \
+  typename _Base::_Vector_impl::template _Asan<>::_Reinit const \
+	__attribute__((__unused__)) __reinit_guard(this->_M_impl)
+#define _GLIBCXX_ASAN_ANNOTATE_GROW(n) \
+  typename _Base::_Vector_impl::template _Asan<>::_Grow \
+	__attribute__((__unused__)) __grow_guard(this->_M_impl, (n))
+#define _GLIBCXX_ASAN_ANNOTATE_GREW(n) __grow_guard._M_grew(n)
+#define _GLIBCXX_ASAN_ANNOTATE_SHRINK(n) \
+  _Base::_Vector_impl::template _Asan<>::_S_shrink(this->_M_impl, n)
+#define _GLIBCXX_ASAN_ANNOTATE_BEFORE_DEALLOC \
+  _Base::_Vector_impl::template _Asan<>::_S_on_dealloc(this->_M_impl)
+#else // ! (_GLIBCXX_SANITIZE_STD_ALLOCATOR && _GLIBCXX_SANITIZE_VECTOR)
+#define _GLIBCXX_ASAN_ANNOTATE_REINIT
+#define _GLIBCXX_ASAN_ANNOTATE_GROW(n)
+#define _GLIBCXX_ASAN_ANNOTATE_GREW(n)
+#define _GLIBCXX_ASAN_ANNOTATE_SHRINK(n)
+#define _GLIBCXX_ASAN_ANNOTATE_BEFORE_DEALLOC
+#endif // _GLIBCXX_SANITIZE_STD_ALLOCATOR && _GLIBCXX_SANITIZE_VECTOR
+      };
+
+    public:
+      typedef _Alloc allocator_type;
+
+      _GLIBCXX20_CONSTEXPR
+      _Tp_alloc_type&
+      _M_get_Tp_allocator() _GLIBCXX_NOEXCEPT
+      { return this->_M_impl; }
+
+      _GLIBCXX20_CONSTEXPR
+      const _Tp_alloc_type&
+      _M_get_Tp_allocator() const _GLIBCXX_NOEXCEPT
+      { return this->_M_impl; }
+
+      _GLIBCXX20_CONSTEXPR
+      allocator_type
+      get_allocator() const _GLIBCXX_NOEXCEPT
+      { return allocator_type(_M_get_Tp_allocator()); }
+
+#if __cplusplus >= 201103L
+      _Vector_base() = default;
+#else
+      _Vector_base() { }
+#endif
+
+      _GLIBCXX20_CONSTEXPR
+      _Vector_base(const allocator_type& __a) _GLIBCXX_NOEXCEPT
+      : _M_impl(__a) { }
+
+      // Kept for ABI compatibility.
+#if !_GLIBCXX_INLINE_VERSION
+      _GLIBCXX20_CONSTEXPR
+      _Vector_base(size_t __n)
+      : _M_impl()
+      { _M_create_storage(__n); }
+#endif
+
+      _GLIBCXX20_CONSTEXPR
+      _Vector_base(size_t __n, const allocator_type& __a)
+      : _M_impl(__a)
+      { _M_create_storage(__n); }
+
+#if __cplusplus >= 201103L
+      _Vector_base(_Vector_base&&) = default;
+
+      // Kept for ABI compatibility.
+# if !_GLIBCXX_INLINE_VERSION
+      _GLIBCXX20_CONSTEXPR
+      _Vector_base(_Tp_alloc_type&& __a) noexcept
+      : _M_impl(std::move(__a)) { }
+
+      _GLIBCXX20_CONSTEXPR
+      _Vector_base(_Vector_base&& __x, const allocator_type& __a)
+      : _M_impl(__a)
+      {
+	if (__x.get_allocator() == __a)
+	  this->_M_impl._M_swap_data(__x._M_impl);
+	else
+	  {
+	    size_t __n = __x._M_impl._M_finish - __x._M_impl._M_start;
+	    _M_create_storage(__n);
+	  }
+      }
+# endif
+
+      _GLIBCXX20_CONSTEXPR
+      _Vector_base(const allocator_type& __a, _Vector_base&& __x)
+      : _M_impl(_Tp_alloc_type(__a), std::move(__x._M_impl))
+      { }
+#endif
+
+      _GLIBCXX20_CONSTEXPR
+      ~_Vector_base() _GLIBCXX_NOEXCEPT
+      {
+	_M_deallocate(_M_impl._M_start,
+		      _M_impl._M_end_of_storage - _M_impl._M_start);
+      }
+
+    public:
+      _Vector_impl _M_impl;
+
+      _GLIBCXX20_CONSTEXPR
+      pointer
+      _M_allocate(size_t __n)
+      {
+	typedef __gnu_cxx::__alloc_traits<_Tp_alloc_type> _Tr;
+	return __n != 0 ? _Tr::allocate(_M_impl, __n) : pointer();
+      }
+
+      _GLIBCXX20_CONSTEXPR
+      void
+      _M_deallocate(pointer __p, size_t __n)
+      {
+	typedef __gnu_cxx::__alloc_traits<_Tp_alloc_type> _Tr;
+	if (__p)
+	  _Tr::deallocate(_M_impl, __p, __n);
+      }
+
+    protected:
+      _GLIBCXX20_CONSTEXPR
+      void
+      _M_create_storage(size_t __n)
+      {
+	this->_M_impl._M_start = this->_M_allocate(__n);
+	this->_M_impl._M_finish = this->_M_impl._M_start;
+	this->_M_impl._M_end_of_storage = this->_M_impl._M_start + __n;
+      }
+    };
+
+  /**
+   *  @brief A standard container which offers fixed time access to
+   *  individual elements in any order.
+   *
+   *  @ingroup sequences
+   *
+   *  @tparam _Tp  Type of element.
+   *  @tparam _Alloc  Allocator type, defaults to allocator<_Tp>.
+   *
+   *  Meets the requirements of a <a href="tables.html#65">container</a>, a
+   *  <a href="tables.html#66">reversible container</a>, and a
+   *  <a href="tables.html#67">sequence</a>, including the
+   *  <a href="tables.html#68">optional sequence requirements</a> with the
+   *  %exception of @c push_front and @c pop_front.
+   *
+   *  In some terminology a %vector can be described as a dynamic
+   *  C-style array, it offers fast and efficient access to individual
+   *  elements in any order and saves the user from worrying about
+   *  memory and size allocation.  Subscripting ( @c [] ) access is
+   *  also provided as with C-style arrays.
+  */
+  template<typename _Tp, typename _Alloc = std::allocator<_Tp> >
+    class vector : protected _Vector_base<_Tp, _Alloc>
+    {
+#ifdef _GLIBCXX_CONCEPT_CHECKS
+      // Concept requirements.
+      typedef typename _Alloc::value_type		_Alloc_value_type;
+# if __cplusplus < 201103L
+      __glibcxx_class_requires(_Tp, _SGIAssignableConcept)
+# endif
+      __glibcxx_class_requires2(_Tp, _Alloc_value_type, _SameTypeConcept)
+#endif
+
+#if __cplusplus >= 201103L
+      static_assert(is_same<typename remove_cv<_Tp>::type, _Tp>::value,
+	  "std::vector must have a non-const, non-volatile value_type");
+# if __cplusplus > 201703L || defined __STRICT_ANSI__
+      static_assert(is_same<typename _Alloc::value_type, _Tp>::value,
+	  "std::vector must have the same value_type as its allocator");
+# endif
+#endif
+
+      typedef _Vector_base<_Tp, _Alloc>			_Base;
+      typedef typename _Base::_Tp_alloc_type		_Tp_alloc_type;
+      typedef __gnu_cxx::__alloc_traits<_Tp_alloc_type>	_Alloc_traits;
+
+    public:
+      typedef _Tp					value_type;
+      typedef typename _Base::pointer			pointer;
+      typedef typename _Alloc_traits::const_pointer	const_pointer;
+      typedef typename _Alloc_traits::reference		reference;
+      typedef typename _Alloc_traits::const_reference	const_reference;
+      typedef __gnu_cxx::__normal_iterator<pointer, vector> iterator;
+      typedef __gnu_cxx::__normal_iterator<const_pointer, vector>
+      const_iterator;
+      typedef std::reverse_iterator<const_iterator>	const_reverse_iterator;
+      typedef std::reverse_iterator<iterator>		reverse_iterator;
+      typedef size_t					size_type;
+      typedef ptrdiff_t					difference_type;
+      typedef _Alloc					allocator_type;
+
+    private:
+#if __cplusplus >= 201103L
+      static constexpr bool
+      _S_nothrow_relocate(true_type)
+      {
+	return noexcept(std::__relocate_a(std::declval<pointer>(),
+					  std::declval<pointer>(),
+					  std::declval<pointer>(),
+					  std::declval<_Tp_alloc_type&>()));
+      }
+
+      static constexpr bool
+      _S_nothrow_relocate(false_type)
+      { return false; }
+
+      static constexpr bool
+      _S_use_relocate()
+      {
+	// Instantiating std::__relocate_a might cause an error outside the
+	// immediate context (in __relocate_object_a's noexcept-specifier),
+	// so only do it if we know the type can be move-inserted into *this.
+	return _S_nothrow_relocate(__is_move_insertable<_Tp_alloc_type>{});
+      }
+
+      static pointer
+      _S_do_relocate(pointer __first, pointer __last, pointer __result,
+		     _Tp_alloc_type& __alloc, true_type) noexcept
+      {
+	return std::__relocate_a(__first, __last, __result, __alloc);
+      }
+
+      static pointer
+      _S_do_relocate(pointer, pointer, pointer __result,
+		     _Tp_alloc_type&, false_type) noexcept
+      { return __result; }
+
+      static _GLIBCXX20_CONSTEXPR pointer
+      _S_relocate(pointer __first, pointer __last, pointer __result,
+		  _Tp_alloc_type& __alloc) noexcept
+      {
+#if __cpp_if_constexpr
+	// All callers have already checked _S_use_relocate() so just do it.
+	return std::__relocate_a(__first, __last, __result, __alloc);
+#else
+	using __do_it = __bool_constant<_S_use_relocate()>;
+	return _S_do_relocate(__first, __last, __result, __alloc, __do_it{});
+#endif
+      }
+#endif // C++11
+
+    protected:
+      using _Base::_M_allocate;
+      using _Base::_M_deallocate;
+      using _Base::_M_impl;
+      using _Base::_M_get_Tp_allocator;
+
+    public:
+      // [23.2.4.1] construct/copy/destroy
+      // (assign() and get_allocator() are also listed in this section)
+
+      /**
+       *  @brief  Creates a %vector with no elements.
+       */
+#if __cplusplus >= 201103L
+      vector() = default;
+#else
+      vector() { }
+#endif
+
+      /**
+       *  @brief  Creates a %vector with no elements.
+       *  @param  __a  An allocator object.
+       */
+      explicit
+      _GLIBCXX20_CONSTEXPR
+      vector(const allocator_type& __a) _GLIBCXX_NOEXCEPT
+      : _Base(__a) { }
+
+#if __cplusplus >= 201103L
+      /**
+       *  @brief  Creates a %vector with default constructed elements.
+       *  @param  __n  The number of elements to initially create.
+       *  @param  __a  An allocator.
+       *
+       *  This constructor fills the %vector with @a __n default
+       *  constructed elements.
+       */
+      explicit
+      _GLIBCXX20_CONSTEXPR
+      vector(size_type __n, const allocator_type& __a = allocator_type())
+      : _Base(_S_check_init_len(__n, __a), __a)
+      { _M_default_initialize(__n); }
+
+      /**
+       *  @brief  Creates a %vector with copies of an exemplar element.
+       *  @param  __n  The number of elements to initially create.
+       *  @param  __value  An element to copy.
+       *  @param  __a  An allocator.
+       *
+       *  This constructor fills the %vector with @a __n copies of @a __value.
+       */
+      _GLIBCXX20_CONSTEXPR
+      vector(size_type __n, const value_type& __value,
+	     const allocator_type& __a = allocator_type())
+      : _Base(_S_check_init_len(__n, __a), __a)
+      { _M_fill_initialize(__n, __value); }
+#else
+      /**
+       *  @brief  Creates a %vector with copies of an exemplar element.
+       *  @param  __n  The number of elements to initially create.
+       *  @param  __value  An element to copy.
+       *  @param  __a  An allocator.
+       *
+       *  This constructor fills the %vector with @a __n copies of @a __value.
+       */
+      explicit
+      vector(size_type __n, const value_type& __value = value_type(),
+	     const allocator_type& __a = allocator_type())
+      : _Base(_S_check_init_len(__n, __a), __a)
+      { _M_fill_initialize(__n, __value); }
+#endif
+
+      /**
+       *  @brief  %Vector copy constructor.
+       *  @param  __x  A %vector of identical element and allocator types.
+       *
+       *  All the elements of @a __x are copied, but any unused capacity in
+       *  @a __x  will not be copied
+       *  (i.e. capacity() == size() in the new %vector).
+       *
+       *  The newly-created %vector uses a copy of the allocator object used
+       *  by @a __x (unless the allocator traits dictate a different object).
+       */
+      _GLIBCXX20_CONSTEXPR
+      vector(const vector& __x)
+      : _Base(__x.size(),
+	_Alloc_traits::_S_select_on_copy(__x._M_get_Tp_allocator()))
+      {
+	this->_M_impl._M_finish =
+	  std::__uninitialized_copy_a(__x.begin(), __x.end(),
+				      this->_M_impl._M_start,
+				      _M_get_Tp_allocator());
+      }
+
+#if __cplusplus >= 201103L
+      /**
+       *  @brief  %Vector move constructor.
+       *
+       *  The newly-created %vector contains the exact contents of the
+       *  moved instance.
+       *  The contents of the moved instance are a valid, but unspecified
+       *  %vector.
+       */
+      vector(vector&&) noexcept = default;
+
+      /// Copy constructor with alternative allocator
+      _GLIBCXX20_CONSTEXPR
+      vector(const vector& __x, const __type_identity_t<allocator_type>& __a)
+      : _Base(__x.size(), __a)
+      {
+	this->_M_impl._M_finish =
+	  std::__uninitialized_copy_a(__x.begin(), __x.end(),
+				      this->_M_impl._M_start,
+				      _M_get_Tp_allocator());
+      }
+
+    private:
+      _GLIBCXX20_CONSTEXPR
+      vector(vector&& __rv, const allocator_type& __m, true_type) noexcept
+      : _Base(__m, std::move(__rv))
+      { }
+
+      _GLIBCXX20_CONSTEXPR
+      vector(vector&& __rv, const allocator_type& __m, false_type)
+      : _Base(__m)
+      {
+	if (__rv.get_allocator() == __m)
+	  this->_M_impl._M_swap_data(__rv._M_impl);
+	else if (!__rv.empty())
+	  {
+	    this->_M_create_storage(__rv.size());
+	    this->_M_impl._M_finish =
+	      std::__uninitialized_move_a(__rv.begin(), __rv.end(),
+					  this->_M_impl._M_start,
+					  _M_get_Tp_allocator());
+	    __rv.clear();
+	  }
+      }
+
+    public:
+      /// Move constructor with alternative allocator
+      _GLIBCXX20_CONSTEXPR
+      vector(vector&& __rv, const __type_identity_t<allocator_type>& __m)
+      noexcept( noexcept(
+	vector(std::declval<vector&&>(), std::declval<const allocator_type&>(),
+	       std::declval<typename _Alloc_traits::is_always_equal>())) )
+      : vector(std::move(__rv), __m, typename _Alloc_traits::is_always_equal{})
+      { }
+
+      /**
+       *  @brief  Builds a %vector from an initializer list.
+       *  @param  __l  An initializer_list.
+       *  @param  __a  An allocator.
+       *
+       *  Create a %vector consisting of copies of the elements in the
+       *  initializer_list @a __l.
+       *
+       *  This will call the element type's copy constructor N times
+       *  (where N is @a __l.size()) and do no memory reallocation.
+       */
+      _GLIBCXX20_CONSTEXPR
+      vector(initializer_list<value_type> __l,
+	     const allocator_type& __a = allocator_type())
+      : _Base(__a)
+      {
+	_M_range_initialize(__l.begin(), __l.end(),
+			    random_access_iterator_tag());
+      }
+#endif
+
+      /**
+       *  @brief  Builds a %vector from a range.
+       *  @param  __first  An input iterator.
+       *  @param  __last  An input iterator.
+       *  @param  __a  An allocator.
+       *
+       *  Create a %vector consisting of copies of the elements from
+       *  [first,last).
+       *
+       *  If the iterators are forward, bidirectional, or
+       *  random-access, then this will call the elements' copy
+       *  constructor N times (where N is distance(first,last)) and do
+       *  no memory reallocation.  But if only input iterators are
+       *  used, then this will do at most 2N calls to the copy
+       *  constructor, and logN memory reallocations.
+       */
+#if __cplusplus >= 201103L
+      template<typename _InputIterator,
+	       typename = std::_RequireInputIter<_InputIterator>>
+	_GLIBCXX20_CONSTEXPR
+	vector(_InputIterator __first, _InputIterator __last,
+	       const allocator_type& __a = allocator_type())
+	: _Base(__a)
+	{
+	  _M_range_initialize(__first, __last,
+			      std::__iterator_category(__first));
+	}
+#else
+      template<typename _InputIterator>
+	vector(_InputIterator __first, _InputIterator __last,
+	       const allocator_type& __a = allocator_type())
+	: _Base(__a)
+	{
+	  // Check whether it's an integral type.  If so, it's not an iterator.
+	  typedef typename std::__is_integer<_InputIterator>::__type _Integral;
+	  _M_initialize_dispatch(__first, __last, _Integral());
+	}
+#endif
+
+      /**
+       *  The dtor only erases the elements, and note that if the
+       *  elements themselves are pointers, the pointed-to memory is
+       *  not touched in any way.  Managing the pointer is the user's
+       *  responsibility.
+       */
+      _GLIBCXX20_CONSTEXPR
+      ~vector() _GLIBCXX_NOEXCEPT
+      {
+	std::_Destroy(this->_M_impl._M_start, this->_M_impl._M_finish,
+		      _M_get_Tp_allocator());
+	_GLIBCXX_ASAN_ANNOTATE_BEFORE_DEALLOC;
+      }
+
+      /**
+       *  @brief  %Vector assignment operator.
+       *  @param  __x  A %vector of identical element and allocator types.
+       *
+       *  All the elements of @a __x are copied, but any unused capacity in
+       *  @a __x will not be copied.
+       *
+       *  Whether the allocator is copied depends on the allocator traits.
+       */
+      _GLIBCXX20_CONSTEXPR
+      vector&
+      operator=(const vector& __x);
+
+#if __cplusplus >= 201103L
+      /**
+       *  @brief  %Vector move assignment operator.
+       *  @param  __x  A %vector of identical element and allocator types.
+       *
+       *  The contents of @a __x are moved into this %vector (without copying,
+       *  if the allocators permit it).
+       *  Afterwards @a __x is a valid, but unspecified %vector.
+       *
+       *  Whether the allocator is moved depends on the allocator traits.
+       */
+      _GLIBCXX20_CONSTEXPR
+      vector&
+      operator=(vector&& __x) noexcept(_Alloc_traits::_S_nothrow_move())
+      {
+	constexpr bool __move_storage =
+	  _Alloc_traits::_S_propagate_on_move_assign()
+	  || _Alloc_traits::_S_always_equal();
+	_M_move_assign(std::move(__x), __bool_constant<__move_storage>());
+	return *this;
+      }
+
+      /**
+       *  @brief  %Vector list assignment operator.
+       *  @param  __l  An initializer_list.
+       *
+       *  This function fills a %vector with copies of the elements in the
+       *  initializer list @a __l.
+       *
+       *  Note that the assignment completely changes the %vector and
+       *  that the resulting %vector's size is the same as the number
+       *  of elements assigned.
+       */
+      _GLIBCXX20_CONSTEXPR
+      vector&
+      operator=(initializer_list<value_type> __l)
+      {
+	this->_M_assign_aux(__l.begin(), __l.end(),
+			    random_access_iterator_tag());
+	return *this;
+      }
+#endif
+
+      /**
+       *  @brief  Assigns a given value to a %vector.
+       *  @param  __n  Number of elements to be assigned.
+       *  @param  __val  Value to be assigned.
+       *
+       *  This function fills a %vector with @a __n copies of the given
+       *  value.  Note that the assignment completely changes the
+       *  %vector and that the resulting %vector's size is the same as
+       *  the number of elements assigned.
+       */
+      _GLIBCXX20_CONSTEXPR
+      void
+      assign(size_type __n, const value_type& __val)
+      { _M_fill_assign(__n, __val); }
+
+      /**
+       *  @brief  Assigns a range to a %vector.
+       *  @param  __first  An input iterator.
+       *  @param  __last   An input iterator.
+       *
+       *  This function fills a %vector with copies of the elements in the
+       *  range [__first,__last).
+       *
+       *  Note that the assignment completely changes the %vector and
+       *  that the resulting %vector's size is the same as the number
+       *  of elements assigned.
+       */
+#if __cplusplus >= 201103L
+      template<typename _InputIterator,
+	       typename = std::_RequireInputIter<_InputIterator>>
+	_GLIBCXX20_CONSTEXPR
+	void
+	assign(_InputIterator __first, _InputIterator __last)
+	{ _M_assign_dispatch(__first, __last, __false_type()); }
+#else
+      template<typename _InputIterator>
+	void
+	assign(_InputIterator __first, _InputIterator __last)
+	{
+	  // Check whether it's an integral type.  If so, it's not an iterator.
+	  typedef typename std::__is_integer<_InputIterator>::__type _Integral;
+	  _M_assign_dispatch(__first, __last, _Integral());
+	}
+#endif
+
+#if __cplusplus >= 201103L
+      /**
+       *  @brief  Assigns an initializer list to a %vector.
+       *  @param  __l  An initializer_list.
+       *
+       *  This function fills a %vector with copies of the elements in the
+       *  initializer list @a __l.
+       *
+       *  Note that the assignment completely changes the %vector and
+       *  that the resulting %vector's size is the same as the number
+       *  of elements assigned.
+       */
+      _GLIBCXX20_CONSTEXPR
+      void
+      assign(initializer_list<value_type> __l)
+      {
+	this->_M_assign_aux(__l.begin(), __l.end(),
+			    random_access_iterator_tag());
+      }
+#endif
+
+      /// Get a copy of the memory allocation object.
+      using _Base::get_allocator;
+
+      // iterators
+      /**
+       *  Returns a read/write iterator that points to the first
+       *  element in the %vector.  Iteration is done in ordinary
+       *  element order.
+       */
+      _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
+      iterator
+      begin() _GLIBCXX_NOEXCEPT
+      { return iterator(this->_M_impl._M_start); }
+
+      /**
+       *  Returns a read-only (constant) iterator that points to the
+       *  first element in the %vector.  Iteration is done in ordinary
+       *  element order.
+       */
+      _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
+      const_iterator
+      begin() const _GLIBCXX_NOEXCEPT
+      { return const_iterator(this->_M_impl._M_start); }
+
+      /**
+       *  Returns a read/write iterator that points one past the last
+       *  element in the %vector.  Iteration is done in ordinary
+       *  element order.
+       */
+      _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
+      iterator
+      end() _GLIBCXX_NOEXCEPT
+      { return iterator(this->_M_impl._M_finish); }
+
+      /**
+       *  Returns a read-only (constant) iterator that points one past
+       *  the last element in the %vector.  Iteration is done in
+       *  ordinary element order.
+       */
+      _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
+      const_iterator
+      end() const _GLIBCXX_NOEXCEPT
+      { return const_iterator(this->_M_impl._M_finish); }
+
+      /**
+       *  Returns a read/write reverse iterator that points to the
+       *  last element in the %vector.  Iteration is done in reverse
+       *  element order.
+       */
+      _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
+      reverse_iterator
+      rbegin() _GLIBCXX_NOEXCEPT
+      { return reverse_iterator(end()); }
+
+      /**
+       *  Returns a read-only (constant) reverse iterator that points
+       *  to the last element in the %vector.  Iteration is done in
+       *  reverse element order.
+       */
+      _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
+      const_reverse_iterator
+      rbegin() const _GLIBCXX_NOEXCEPT
+      { return const_reverse_iterator(end()); }
+
+      /**
+       *  Returns a read/write reverse iterator that points to one
+       *  before the first element in the %vector.  Iteration is done
+       *  in reverse element order.
+       */
+      _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
+      reverse_iterator
+      rend() _GLIBCXX_NOEXCEPT
+      { return reverse_iterator(begin()); }
+
+      /**
+       *  Returns a read-only (constant) reverse iterator that points
+       *  to one before the first element in the %vector.  Iteration
+       *  is done in reverse element order.
+       */
+      _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
+      const_reverse_iterator
+      rend() const _GLIBCXX_NOEXCEPT
+      { return const_reverse_iterator(begin()); }
+
+#if __cplusplus >= 201103L
+      /**
+       *  Returns a read-only (constant) iterator that points to the
+       *  first element in the %vector.  Iteration is done in ordinary
+       *  element order.
+       */
+      [[__nodiscard__]] _GLIBCXX20_CONSTEXPR
+      const_iterator
+      cbegin() const noexcept
+      { return const_iterator(this->_M_impl._M_start); }
+
+      /**
+       *  Returns a read-only (constant) iterator that points one past
+       *  the last element in the %vector.  Iteration is done in
+       *  ordinary element order.
+       */
+      [[__nodiscard__]] _GLIBCXX20_CONSTEXPR
+      const_iterator
+      cend() const noexcept
+      { return const_iterator(this->_M_impl._M_finish); }
+
+      /**
+       *  Returns a read-only (constant) reverse iterator that points
+       *  to the last element in the %vector.  Iteration is done in
+       *  reverse element order.
+       */
+      [[__nodiscard__]] _GLIBCXX20_CONSTEXPR
+      const_reverse_iterator
+      crbegin() const noexcept
+      { return const_reverse_iterator(end()); }
+
+      /**
+       *  Returns a read-only (constant) reverse iterator that points
+       *  to one before the first element in the %vector.  Iteration
+       *  is done in reverse element order.
+       */
+      [[__nodiscard__]] _GLIBCXX20_CONSTEXPR
+      const_reverse_iterator
+      crend() const noexcept
+      { return const_reverse_iterator(begin()); }
+#endif
+
+      // [23.2.4.2] capacity
+      /**  Returns the number of elements in the %vector.  */
+      _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
+      size_type
+      size() const _GLIBCXX_NOEXCEPT
+      { return size_type(this->_M_impl._M_finish - this->_M_impl._M_start); }
+
+      /**  Returns the size() of the largest possible %vector.  */
+      _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
+      size_type
+      max_size() const _GLIBCXX_NOEXCEPT
+      { return _S_max_size(_M_get_Tp_allocator()); }
+
+#if __cplusplus >= 201103L
+      /**
+       *  @brief  Resizes the %vector to the specified number of elements.
+       *  @param  __new_size  Number of elements the %vector should contain.
+       *
+       *  This function will %resize the %vector to the specified
+       *  number of elements.  If the number is smaller than the
+       *  %vector's current size the %vector is truncated, otherwise
+       *  default constructed elements are appended.
+       */
+      _GLIBCXX20_CONSTEXPR
+      void
+      resize(size_type __new_size)
+      {
+	if (__new_size > size())
+	  _M_default_append(__new_size - size());
+	else if (__new_size < size())
+	  _M_erase_at_end(this->_M_impl._M_start + __new_size);
+      }
+
+      /**
+       *  @brief  Resizes the %vector to the specified number of elements.
+       *  @param  __new_size  Number of elements the %vector should contain.
+       *  @param  __x  Data with which new elements should be populated.
+       *
+       *  This function will %resize the %vector to the specified
+       *  number of elements.  If the number is smaller than the
+       *  %vector's current size the %vector is truncated, otherwise
+       *  the %vector is extended and new elements are populated with
+       *  given data.
+       */
+      _GLIBCXX20_CONSTEXPR
+      void
+      resize(size_type __new_size, const value_type& __x)
+      {
+	if (__new_size > size())
+	  _M_fill_insert(end(), __new_size - size(), __x);
+	else if (__new_size < size())
+	  _M_erase_at_end(this->_M_impl._M_start + __new_size);
+      }
+#else
+      /**
+       *  @brief  Resizes the %vector to the specified number of elements.
+       *  @param  __new_size  Number of elements the %vector should contain.
+       *  @param  __x  Data with which new elements should be populated.
+       *
+       *  This function will %resize the %vector to the specified
+       *  number of elements.  If the number is smaller than the
+       *  %vector's current size the %vector is truncated, otherwise
+       *  the %vector is extended and new elements are populated with
+       *  given data.
+       */
+      _GLIBCXX20_CONSTEXPR
+      void
+      resize(size_type __new_size, value_type __x = value_type())
+      {
+	if (__new_size > size())
+	  _M_fill_insert(end(), __new_size - size(), __x);
+	else if (__new_size < size())
+	  _M_erase_at_end(this->_M_impl._M_start + __new_size);
+      }
+#endif
+
+#if __cplusplus >= 201103L
+      /**  A non-binding request to reduce capacity() to size().  */
+      _GLIBCXX20_CONSTEXPR
+      void
+      shrink_to_fit()
+      { _M_shrink_to_fit(); }
+#endif
+
+      /**
+       *  Returns the total number of elements that the %vector can
+       *  hold before needing to allocate more memory.
+       */
+      _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
+      size_type
+      capacity() const _GLIBCXX_NOEXCEPT
+      { return size_type(this->_M_impl._M_end_of_storage
+			 - this->_M_impl._M_start); }
+
+      /**
+       *  Returns true if the %vector is empty.  (Thus begin() would
+       *  equal end().)
+       */
+      _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
+      bool
+      empty() const _GLIBCXX_NOEXCEPT
+      { return begin() == end(); }
+
+      /**
+       *  @brief  Attempt to preallocate enough memory for specified number of
+       *          elements.
+       *  @param  __n  Number of elements required.
+       *  @throw  std::length_error  If @a n exceeds @c max_size().
+       *
+       *  This function attempts to reserve enough memory for the
+       *  %vector to hold the specified number of elements.  If the
+       *  number requested is more than max_size(), length_error is
+       *  thrown.
+       *
+       *  The advantage of this function is that if optimal code is a
+       *  necessity and the user can determine the number of elements
+       *  that will be required, the user can reserve the memory in
+       *  %advance, and thus prevent a possible reallocation of memory
+       *  and copying of %vector data.
+       */
+      _GLIBCXX20_CONSTEXPR
+      void
+      reserve(size_type __n);
+
+      // element access
+      /**
+       *  @brief  Subscript access to the data contained in the %vector.
+       *  @param __n The index of the element for which data should be
+       *  accessed.
+       *  @return  Read/write reference to data.
+       *
+       *  This operator allows for easy, array-style, data access.
+       *  Note that data access with this operator is unchecked and
+       *  out_of_range lookups are not defined. (For checked lookups
+       *  see at().)
+       */
+      _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
+      reference
+      operator[](size_type __n) _GLIBCXX_NOEXCEPT
+      {
+	__glibcxx_requires_subscript(__n);
+	return *(this->_M_impl._M_start + __n);
+      }
+
+      /**
+       *  @brief  Subscript access to the data contained in the %vector.
+       *  @param __n The index of the element for which data should be
+       *  accessed.
+       *  @return  Read-only (constant) reference to data.
+       *
+       *  This operator allows for easy, array-style, data access.
+       *  Note that data access with this operator is unchecked and
+       *  out_of_range lookups are not defined. (For checked lookups
+       *  see at().)
+       */
+      _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
+      const_reference
+      operator[](size_type __n) const _GLIBCXX_NOEXCEPT
+      {
+	__glibcxx_requires_subscript(__n);
+	return *(this->_M_impl._M_start + __n);
+      }
+
+    protected:
+      /// Safety check used only from at().
+      _GLIBCXX20_CONSTEXPR
+      void
+      _M_range_check(size_type __n) const
+      {
+	if (__n >= this->size())
+	  __throw_out_of_range_fmt(__N("vector::_M_range_check: __n "
+				       "(which is %zu) >= this->size() "
+				       "(which is %zu)"),
+				   __n, this->size());
+      }
+
+    public:
+      /**
+       *  @brief  Provides access to the data contained in the %vector.
+       *  @param __n The index of the element for which data should be
+       *  accessed.
+       *  @return  Read/write reference to data.
+       *  @throw  std::out_of_range  If @a __n is an invalid index.
+       *
+       *  This function provides for safer data access.  The parameter
+       *  is first checked that it is in the range of the vector.  The
+       *  function throws out_of_range if the check fails.
+       */
+      _GLIBCXX20_CONSTEXPR
+      reference
+      at(size_type __n)
+      {
+	_M_range_check(__n);
+	return (*this)[__n];
+      }
+
+      /**
+       *  @brief  Provides access to the data contained in the %vector.
+       *  @param __n The index of the element for which data should be
+       *  accessed.
+       *  @return  Read-only (constant) reference to data.
+       *  @throw  std::out_of_range  If @a __n is an invalid index.
+       *
+       *  This function provides for safer data access.  The parameter
+       *  is first checked that it is in the range of the vector.  The
+       *  function throws out_of_range if the check fails.
+       */
+      _GLIBCXX20_CONSTEXPR
+      const_reference
+      at(size_type __n) const
+      {
+	_M_range_check(__n);
+	return (*this)[__n];
+      }
+
+      /**
+       *  Returns a read/write reference to the data at the first
+       *  element of the %vector.
+       */
+      _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
+      reference
+      front() _GLIBCXX_NOEXCEPT
+      {
+	__glibcxx_requires_nonempty();
+	return *begin();
+      }
+
+      /**
+       *  Returns a read-only (constant) reference to the data at the first
+       *  element of the %vector.
+       */
+      _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
+      const_reference
+      front() const _GLIBCXX_NOEXCEPT
+      {
+	__glibcxx_requires_nonempty();
+	return *begin();
+      }
+
+      /**
+       *  Returns a read/write reference to the data at the last
+       *  element of the %vector.
+       */
+      _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
+      reference
+      back() _GLIBCXX_NOEXCEPT
+      {
+	__glibcxx_requires_nonempty();
+	return *(end() - 1);
+      }
+
+      /**
+       *  Returns a read-only (constant) reference to the data at the
+       *  last element of the %vector.
+       */
+      _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
+      const_reference
+      back() const _GLIBCXX_NOEXCEPT
+      {
+	__glibcxx_requires_nonempty();
+	return *(end() - 1);
+      }
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // DR 464. Suggestion for new member functions in standard containers.
+      // data access
+      /**
+       *   Returns a pointer such that [data(), data() + size()) is a valid
+       *   range.  For a non-empty %vector, data() == &front().
+       */
+      _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
+      _Tp*
+      data() _GLIBCXX_NOEXCEPT
+      { return _M_data_ptr(this->_M_impl._M_start); }
+
+      _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
+      const _Tp*
+      data() const _GLIBCXX_NOEXCEPT
+      { return _M_data_ptr(this->_M_impl._M_start); }
+
+      // [23.2.4.3] modifiers
+      /**
+       *  @brief  Add data to the end of the %vector.
+       *  @param  __x  Data to be added.
+       *
+       *  This is a typical stack operation.  The function creates an
+       *  element at the end of the %vector and assigns the given data
+       *  to it.  Due to the nature of a %vector this operation can be
+       *  done in constant time if the %vector has preallocated space
+       *  available.
+       */
+      _GLIBCXX20_CONSTEXPR
+      void
+      push_back(const value_type& __x)
+      {
+	if (this->_M_impl._M_finish != this->_M_impl._M_end_of_storage)
+	  {
+	    _GLIBCXX_ASAN_ANNOTATE_GROW(1);
+	    _Alloc_traits::construct(this->_M_impl, this->_M_impl._M_finish,
+				     __x);
+	    ++this->_M_impl._M_finish;
+	    _GLIBCXX_ASAN_ANNOTATE_GREW(1);
+	  }
+	else
+	  _M_realloc_insert(end(), __x);
+      }
+
+#if __cplusplus >= 201103L
+      _GLIBCXX20_CONSTEXPR
+      void
+      push_back(value_type&& __x)
+      { emplace_back(std::move(__x)); }
+
+      template<typename... _Args>
+#if __cplusplus > 201402L
+	_GLIBCXX20_CONSTEXPR
+	reference
+#else
+	void
+#endif
+	emplace_back(_Args&&... __args);
+#endif
+
+      /**
+       *  @brief  Removes last element.
+       *
+       *  This is a typical stack operation. It shrinks the %vector by one.
+       *
+       *  Note that no data is returned, and if the last element's
+       *  data is needed, it should be retrieved before pop_back() is
+       *  called.
+       */
+      _GLIBCXX20_CONSTEXPR
+      void
+      pop_back() _GLIBCXX_NOEXCEPT
+      {
+	__glibcxx_requires_nonempty();
+	--this->_M_impl._M_finish;
+	_Alloc_traits::destroy(this->_M_impl, this->_M_impl._M_finish);
+	_GLIBCXX_ASAN_ANNOTATE_SHRINK(1);
+      }
+
+#if __cplusplus >= 201103L
+      /**
+       *  @brief  Inserts an object in %vector before specified iterator.
+       *  @param  __position  A const_iterator into the %vector.
+       *  @param  __args  Arguments.
+       *  @return  An iterator that points to the inserted data.
+       *
+       *  This function will insert an object of type T constructed
+       *  with T(std::forward<Args>(args)...) before the specified location.
+       *  Note that this kind of operation could be expensive for a %vector
+       *  and if it is frequently used the user should consider using
+       *  std::list.
+       */
+      template<typename... _Args>
+	_GLIBCXX20_CONSTEXPR
+	iterator
+	emplace(const_iterator __position, _Args&&... __args)
+	{ return _M_emplace_aux(__position, std::forward<_Args>(__args)...); }
+
+      /**
+       *  @brief  Inserts given value into %vector before specified iterator.
+       *  @param  __position  A const_iterator into the %vector.
+       *  @param  __x  Data to be inserted.
+       *  @return  An iterator that points to the inserted data.
+       *
+       *  This function will insert a copy of the given value before
+       *  the specified location.  Note that this kind of operation
+       *  could be expensive for a %vector and if it is frequently
+       *  used the user should consider using std::list.
+       */
+      _GLIBCXX20_CONSTEXPR
+      iterator
+      insert(const_iterator __position, const value_type& __x);
+#else
+      /**
+       *  @brief  Inserts given value into %vector before specified iterator.
+       *  @param  __position  An iterator into the %vector.
+       *  @param  __x  Data to be inserted.
+       *  @return  An iterator that points to the inserted data.
+       *
+       *  This function will insert a copy of the given value before
+       *  the specified location.  Note that this kind of operation
+       *  could be expensive for a %vector and if it is frequently
+       *  used the user should consider using std::list.
+       */
+      iterator
+      insert(iterator __position, const value_type& __x);
+#endif
+
+#if __cplusplus >= 201103L
+      /**
+       *  @brief  Inserts given rvalue into %vector before specified iterator.
+       *  @param  __position  A const_iterator into the %vector.
+       *  @param  __x  Data to be inserted.
+       *  @return  An iterator that points to the inserted data.
+       *
+       *  This function will insert a copy of the given rvalue before
+       *  the specified location.  Note that this kind of operation
+       *  could be expensive for a %vector and if it is frequently
+       *  used the user should consider using std::list.
+       */
+      _GLIBCXX20_CONSTEXPR
+      iterator
+      insert(const_iterator __position, value_type&& __x)
+      { return _M_insert_rval(__position, std::move(__x)); }
+
+      /**
+       *  @brief  Inserts an initializer_list into the %vector.
+       *  @param  __position  An iterator into the %vector.
+       *  @param  __l  An initializer_list.
+       *
+       *  This function will insert copies of the data in the
+       *  initializer_list @a l into the %vector before the location
+       *  specified by @a position.
+       *
+       *  Note that this kind of operation could be expensive for a
+       *  %vector and if it is frequently used the user should
+       *  consider using std::list.
+       */
+      _GLIBCXX20_CONSTEXPR
+      iterator
+      insert(const_iterator __position, initializer_list<value_type> __l)
+      {
+	auto __offset = __position - cbegin();
+	_M_range_insert(begin() + __offset, __l.begin(), __l.end(),
+			std::random_access_iterator_tag());
+	return begin() + __offset;
+      }
+#endif
+
+#if __cplusplus >= 201103L
+      /**
+       *  @brief  Inserts a number of copies of given data into the %vector.
+       *  @param  __position  A const_iterator into the %vector.
+       *  @param  __n  Number of elements to be inserted.
+       *  @param  __x  Data to be inserted.
+       *  @return  An iterator that points to the inserted data.
+       *
+       *  This function will insert a specified number of copies of
+       *  the given data before the location specified by @a position.
+       *
+       *  Note that this kind of operation could be expensive for a
+       *  %vector and if it is frequently used the user should
+       *  consider using std::list.
+       */
+      _GLIBCXX20_CONSTEXPR
+      iterator
+      insert(const_iterator __position, size_type __n, const value_type& __x)
+      {
+	difference_type __offset = __position - cbegin();
+	_M_fill_insert(begin() + __offset, __n, __x);
+	return begin() + __offset;
+      }
+#else
+      /**
+       *  @brief  Inserts a number of copies of given data into the %vector.
+       *  @param  __position  An iterator into the %vector.
+       *  @param  __n  Number of elements to be inserted.
+       *  @param  __x  Data to be inserted.
+       *
+       *  This function will insert a specified number of copies of
+       *  the given data before the location specified by @a position.
+       *
+       *  Note that this kind of operation could be expensive for a
+       *  %vector and if it is frequently used the user should
+       *  consider using std::list.
+       */
+      void
+      insert(iterator __position, size_type __n, const value_type& __x)
+      { _M_fill_insert(__position, __n, __x); }
+#endif
+
+#if __cplusplus >= 201103L
+      /**
+       *  @brief  Inserts a range into the %vector.
+       *  @param  __position  A const_iterator into the %vector.
+       *  @param  __first  An input iterator.
+       *  @param  __last   An input iterator.
+       *  @return  An iterator that points to the inserted data.
+       *
+       *  This function will insert copies of the data in the range
+       *  [__first,__last) into the %vector before the location specified
+       *  by @a pos.
+       *
+       *  Note that this kind of operation could be expensive for a
+       *  %vector and if it is frequently used the user should
+       *  consider using std::list.
+       */
+      template<typename _InputIterator,
+	       typename = std::_RequireInputIter<_InputIterator>>
+	_GLIBCXX20_CONSTEXPR
+	iterator
+	insert(const_iterator __position, _InputIterator __first,
+	       _InputIterator __last)
+	{
+	  difference_type __offset = __position - cbegin();
+	  _M_insert_dispatch(begin() + __offset,
+			     __first, __last, __false_type());
+	  return begin() + __offset;
+	}
+#else
+      /**
+       *  @brief  Inserts a range into the %vector.
+       *  @param  __position  An iterator into the %vector.
+       *  @param  __first  An input iterator.
+       *  @param  __last   An input iterator.
+       *
+       *  This function will insert copies of the data in the range
+       *  [__first,__last) into the %vector before the location specified
+       *  by @a pos.
+       *
+       *  Note that this kind of operation could be expensive for a
+       *  %vector and if it is frequently used the user should
+       *  consider using std::list.
+       */
+      template<typename _InputIterator>
+	void
+	insert(iterator __position, _InputIterator __first,
+	       _InputIterator __last)
+	{
+	  // Check whether it's an integral type.  If so, it's not an iterator.
+	  typedef typename std::__is_integer<_InputIterator>::__type _Integral;
+	  _M_insert_dispatch(__position, __first, __last, _Integral());
+	}
+#endif
+
+      /**
+       *  @brief  Remove element at given position.
+       *  @param  __position  Iterator pointing to element to be erased.
+       *  @return  An iterator pointing to the next element (or end()).
+       *
+       *  This function will erase the element at the given position and thus
+       *  shorten the %vector by one.
+       *
+       *  Note This operation could be expensive and if it is
+       *  frequently used the user should consider using std::list.
+       *  The user is also cautioned that this function only erases
+       *  the element, and that if the element is itself a pointer,
+       *  the pointed-to memory is not touched in any way.  Managing
+       *  the pointer is the user's responsibility.
+       */
+      _GLIBCXX20_CONSTEXPR
+      iterator
+#if __cplusplus >= 201103L
+      erase(const_iterator __position)
+      { return _M_erase(begin() + (__position - cbegin())); }
+#else
+      erase(iterator __position)
+      { return _M_erase(__position); }
+#endif
+
+      /**
+       *  @brief  Remove a range of elements.
+       *  @param  __first  Iterator pointing to the first element to be erased.
+       *  @param  __last  Iterator pointing to one past the last element to be
+       *                  erased.
+       *  @return  An iterator pointing to the element pointed to by @a __last
+       *           prior to erasing (or end()).
+       *
+       *  This function will erase the elements in the range
+       *  [__first,__last) and shorten the %vector accordingly.
+       *
+       *  Note This operation could be expensive and if it is
+       *  frequently used the user should consider using std::list.
+       *  The user is also cautioned that this function only erases
+       *  the elements, and that if the elements themselves are
+       *  pointers, the pointed-to memory is not touched in any way.
+       *  Managing the pointer is the user's responsibility.
+       */
+      _GLIBCXX20_CONSTEXPR
+      iterator
+#if __cplusplus >= 201103L
+      erase(const_iterator __first, const_iterator __last)
+      {
+	const auto __beg = begin();
+	const auto __cbeg = cbegin();
+	return _M_erase(__beg + (__first - __cbeg), __beg + (__last - __cbeg));
+      }
+#else
+      erase(iterator __first, iterator __last)
+      { return _M_erase(__first, __last); }
+#endif
+
+      /**
+       *  @brief  Swaps data with another %vector.
+       *  @param  __x  A %vector of the same element and allocator types.
+       *
+       *  This exchanges the elements between two vectors in constant time.
+       *  (Three pointers, so it should be quite fast.)
+       *  Note that the global std::swap() function is specialized such that
+       *  std::swap(v1,v2) will feed to this function.
+       *
+       *  Whether the allocators are swapped depends on the allocator traits.
+       */
+      _GLIBCXX20_CONSTEXPR
+      void
+      swap(vector& __x) _GLIBCXX_NOEXCEPT
+      {
+#if __cplusplus >= 201103L
+	__glibcxx_assert(_Alloc_traits::propagate_on_container_swap::value
+			 || _M_get_Tp_allocator() == __x._M_get_Tp_allocator());
+#endif
+	this->_M_impl._M_swap_data(__x._M_impl);
+	_Alloc_traits::_S_on_swap(_M_get_Tp_allocator(),
+				  __x._M_get_Tp_allocator());
+      }
+
+      /**
+       *  Erases all the elements.  Note that this function only erases the
+       *  elements, and that if the elements themselves are pointers, the
+       *  pointed-to memory is not touched in any way.  Managing the pointer is
+       *  the user's responsibility.
+       */
+      _GLIBCXX20_CONSTEXPR
+      void
+      clear() _GLIBCXX_NOEXCEPT
+      { _M_erase_at_end(this->_M_impl._M_start); }
+
+    protected:
+      /**
+       *  Memory expansion handler.  Uses the member allocation function to
+       *  obtain @a n bytes of memory, and then copies [first,last) into it.
+       */
+      template<typename _ForwardIterator>
+	_GLIBCXX20_CONSTEXPR
+	pointer
+	_M_allocate_and_copy(size_type __n,
+			     _ForwardIterator __first, _ForwardIterator __last)
+	{
+	  pointer __result = this->_M_allocate(__n);
+	  __try
+	    {
+	      std::__uninitialized_copy_a(__first, __last, __result,
+					  _M_get_Tp_allocator());
+	      return __result;
+	    }
+	  __catch(...)
+	    {
+	      _M_deallocate(__result, __n);
+	      __throw_exception_again;
+	    }
+	}
+
+
+      // Internal constructor functions follow.
+
+      // Called by the range constructor to implement [23.1.1]/9
+
+#if __cplusplus < 201103L
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 438. Ambiguity in the "do the right thing" clause
+      template<typename _Integer>
+	void
+	_M_initialize_dispatch(_Integer __n, _Integer __value, __true_type)
+	{
+	  this->_M_impl._M_start = _M_allocate(_S_check_init_len(
+		static_cast<size_type>(__n), _M_get_Tp_allocator()));
+	  this->_M_impl._M_end_of_storage =
+	    this->_M_impl._M_start + static_cast<size_type>(__n);
+	  _M_fill_initialize(static_cast<size_type>(__n), __value);
+	}
+
+      // Called by the range constructor to implement [23.1.1]/9
+      template<typename _InputIterator>
+	void
+	_M_initialize_dispatch(_InputIterator __first, _InputIterator __last,
+			       __false_type)
+	{
+	  _M_range_initialize(__first, __last,
+			      std::__iterator_category(__first));
+	}
+#endif
+
+      // Called by the second initialize_dispatch above
+      template<typename _InputIterator>
+	_GLIBCXX20_CONSTEXPR
+	void
+	_M_range_initialize(_InputIterator __first, _InputIterator __last,
+			    std::input_iterator_tag)
+	{
+	  __try {
+	    for (; __first != __last; ++__first)
+#if __cplusplus >= 201103L
+	      emplace_back(*__first);
+#else
+	      push_back(*__first);
+#endif
+	  } __catch(...) {
+	    clear();
+	    __throw_exception_again;
+	  }
+	}
+
+      // Called by the second initialize_dispatch above
+      template<typename _ForwardIterator>
+	_GLIBCXX20_CONSTEXPR
+	void
+	_M_range_initialize(_ForwardIterator __first, _ForwardIterator __last,
+			    std::forward_iterator_tag)
+	{
+	  const size_type __n = std::distance(__first, __last);
+	  this->_M_impl._M_start
+	    = this->_M_allocate(_S_check_init_len(__n, _M_get_Tp_allocator()));
+	  this->_M_impl._M_end_of_storage = this->_M_impl._M_start + __n;
+	  this->_M_impl._M_finish =
+	    std::__uninitialized_copy_a(__first, __last,
+					this->_M_impl._M_start,
+					_M_get_Tp_allocator());
+	}
+
+      // Called by the first initialize_dispatch above and by the
+      // vector(n,value,a) constructor.
+      _GLIBCXX20_CONSTEXPR
+      void
+      _M_fill_initialize(size_type __n, const value_type& __value)
+      {
+	this->_M_impl._M_finish =
+	  std::__uninitialized_fill_n_a(this->_M_impl._M_start, __n, __value,
+					_M_get_Tp_allocator());
+      }
+
+#if __cplusplus >= 201103L
+      // Called by the vector(n) constructor.
+      _GLIBCXX20_CONSTEXPR
+      void
+      _M_default_initialize(size_type __n)
+      {
+	this->_M_impl._M_finish =
+	  std::__uninitialized_default_n_a(this->_M_impl._M_start, __n,
+					   _M_get_Tp_allocator());
+      }
+#endif
+
+      // Internal assign functions follow.  The *_aux functions do the actual
+      // assignment work for the range versions.
+
+      // Called by the range assign to implement [23.1.1]/9
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 438. Ambiguity in the "do the right thing" clause
+      template<typename _Integer>
+	_GLIBCXX20_CONSTEXPR
+	void
+	_M_assign_dispatch(_Integer __n, _Integer __val, __true_type)
+	{ _M_fill_assign(__n, __val); }
+
+      // Called by the range assign to implement [23.1.1]/9
+      template<typename _InputIterator>
+	_GLIBCXX20_CONSTEXPR
+	void
+	_M_assign_dispatch(_InputIterator __first, _InputIterator __last,
+			   __false_type)
+	{ _M_assign_aux(__first, __last, std::__iterator_category(__first)); }
+
+      // Called by the second assign_dispatch above
+      template<typename _InputIterator>
+	_GLIBCXX20_CONSTEXPR
+	void
+	_M_assign_aux(_InputIterator __first, _InputIterator __last,
+		      std::input_iterator_tag);
+
+      // Called by the second assign_dispatch above
+      template<typename _ForwardIterator>
+	_GLIBCXX20_CONSTEXPR
+	void
+	_M_assign_aux(_ForwardIterator __first, _ForwardIterator __last,
+		      std::forward_iterator_tag);
+
+      // Called by assign(n,t), and the range assign when it turns out
+      // to be the same thing.
+      _GLIBCXX20_CONSTEXPR
+      void
+      _M_fill_assign(size_type __n, const value_type& __val);
+
+      // Internal insert functions follow.
+
+      // Called by the range insert to implement [23.1.1]/9
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 438. Ambiguity in the "do the right thing" clause
+      template<typename _Integer>
+	_GLIBCXX20_CONSTEXPR
+	void
+	_M_insert_dispatch(iterator __pos, _Integer __n, _Integer __val,
+			   __true_type)
+	{ _M_fill_insert(__pos, __n, __val); }
+
+      // Called by the range insert to implement [23.1.1]/9
+      template<typename _InputIterator>
+	_GLIBCXX20_CONSTEXPR
+	void
+	_M_insert_dispatch(iterator __pos, _InputIterator __first,
+			   _InputIterator __last, __false_type)
+	{
+	  _M_range_insert(__pos, __first, __last,
+			  std::__iterator_category(__first));
+	}
+
+      // Called by the second insert_dispatch above
+      template<typename _InputIterator>
+	_GLIBCXX20_CONSTEXPR
+	void
+	_M_range_insert(iterator __pos, _InputIterator __first,
+			_InputIterator __last, std::input_iterator_tag);
+
+      // Called by the second insert_dispatch above
+      template<typename _ForwardIterator>
+	_GLIBCXX20_CONSTEXPR
+	void
+	_M_range_insert(iterator __pos, _ForwardIterator __first,
+			_ForwardIterator __last, std::forward_iterator_tag);
+
+      // Called by insert(p,n,x), and the range insert when it turns out to be
+      // the same thing.
+      _GLIBCXX20_CONSTEXPR
+      void
+      _M_fill_insert(iterator __pos, size_type __n, const value_type& __x);
+
+#if __cplusplus >= 201103L
+      // Called by resize(n).
+      _GLIBCXX20_CONSTEXPR
+      void
+      _M_default_append(size_type __n);
+
+      _GLIBCXX20_CONSTEXPR
+      bool
+      _M_shrink_to_fit();
+#endif
+
+#if __cplusplus < 201103L
+      // Called by insert(p,x)
+      void
+      _M_insert_aux(iterator __position, const value_type& __x);
+
+      void
+      _M_realloc_insert(iterator __position, const value_type& __x);
+#else
+      // A value_type object constructed with _Alloc_traits::construct()
+      // and destroyed with _Alloc_traits::destroy().
+      struct _Temporary_value
+      {
+	template<typename... _Args>
+	  _GLIBCXX20_CONSTEXPR explicit
+	  _Temporary_value(vector* __vec, _Args&&... __args) : _M_this(__vec)
+	  {
+	    _Alloc_traits::construct(_M_this->_M_impl, _M_ptr(),
+				     std::forward<_Args>(__args)...);
+	  }
+
+	_GLIBCXX20_CONSTEXPR
+	~_Temporary_value()
+	{ _Alloc_traits::destroy(_M_this->_M_impl, _M_ptr()); }
+
+	_GLIBCXX20_CONSTEXPR value_type&
+	_M_val() noexcept { return _M_storage._M_val; }
+
+      private:
+	_GLIBCXX20_CONSTEXPR _Tp*
+	_M_ptr() noexcept { return std::__addressof(_M_storage._M_val); }
+
+	union _Storage
+	{
+	  constexpr _Storage() : _M_byte() { }
+	  _GLIBCXX20_CONSTEXPR ~_Storage() { }
+	  _Storage& operator=(const _Storage&) = delete;
+	  unsigned char _M_byte;
+	  _Tp _M_val;
+	};
+
+	vector*  _M_this;
+	_Storage _M_storage;
+      };
+
+      // Called by insert(p,x) and other functions when insertion needs to
+      // reallocate or move existing elements. _Arg is either _Tp& or _Tp.
+      template<typename _Arg>
+	_GLIBCXX20_CONSTEXPR
+	void
+	_M_insert_aux(iterator __position, _Arg&& __arg);
+
+      template<typename... _Args>
+	_GLIBCXX20_CONSTEXPR
+	void
+	_M_realloc_insert(iterator __position, _Args&&... __args);
+
+      // Either move-construct at the end, or forward to _M_insert_aux.
+      _GLIBCXX20_CONSTEXPR
+      iterator
+      _M_insert_rval(const_iterator __position, value_type&& __v);
+
+      // Try to emplace at the end, otherwise forward to _M_insert_aux.
+      template<typename... _Args>
+	_GLIBCXX20_CONSTEXPR
+	iterator
+	_M_emplace_aux(const_iterator __position, _Args&&... __args);
+
+      // Emplacing an rvalue of the correct type can use _M_insert_rval.
+      _GLIBCXX20_CONSTEXPR
+      iterator
+      _M_emplace_aux(const_iterator __position, value_type&& __v)
+      { return _M_insert_rval(__position, std::move(__v)); }
+#endif
+
+      // Called by _M_fill_insert, _M_insert_aux etc.
+      _GLIBCXX20_CONSTEXPR
+      size_type
+      _M_check_len(size_type __n, const char* __s) const
+      {
+	if (max_size() - size() < __n)
+	  __throw_length_error(__N(__s));
+
+	const size_type __len = size() + (std::max)(size(), __n);
+	return (__len < size() || __len > max_size()) ? max_size() : __len;
+      }
+
+      // Called by constructors to check initial size.
+      static _GLIBCXX20_CONSTEXPR size_type
+      _S_check_init_len(size_type __n, const allocator_type& __a)
+      {
+	if (__n > _S_max_size(_Tp_alloc_type(__a)))
+	  __throw_length_error(
+	      __N("cannot create std::vector larger than max_size()"));
+	return __n;
+      }
+
+      static _GLIBCXX20_CONSTEXPR size_type
+      _S_max_size(const _Tp_alloc_type& __a) _GLIBCXX_NOEXCEPT
+      {
+	// std::distance(begin(), end()) cannot be greater than PTRDIFF_MAX,
+	// and realistically we can't store more than PTRDIFF_MAX/sizeof(T)
+	// (even if std::allocator_traits::max_size says we can).
+	const size_t __diffmax
+	  = __gnu_cxx::__numeric_traits<ptrdiff_t>::__max / sizeof(_Tp);
+	const size_t __allocmax = _Alloc_traits::max_size(__a);
+	return (std::min)(__diffmax, __allocmax);
+      }
+
+      // Internal erase functions follow.
+
+      // Called by erase(q1,q2), clear(), resize(), _M_fill_assign,
+      // _M_assign_aux.
+      _GLIBCXX20_CONSTEXPR
+      void
+      _M_erase_at_end(pointer __pos) _GLIBCXX_NOEXCEPT
+      {
+	if (size_type __n = this->_M_impl._M_finish - __pos)
+	  {
+	    std::_Destroy(__pos, this->_M_impl._M_finish,
+			  _M_get_Tp_allocator());
+	    this->_M_impl._M_finish = __pos;
+	    _GLIBCXX_ASAN_ANNOTATE_SHRINK(__n);
+	  }
+      }
+
+      _GLIBCXX20_CONSTEXPR
+      iterator
+      _M_erase(iterator __position);
+
+      _GLIBCXX20_CONSTEXPR
+      iterator
+      _M_erase(iterator __first, iterator __last);
+
+#if __cplusplus >= 201103L
+    private:
+      // Constant-time move assignment when source object's memory can be
+      // moved, either because the source's allocator will move too
+      // or because the allocators are equal.
+      _GLIBCXX20_CONSTEXPR
+      void
+      _M_move_assign(vector&& __x, true_type) noexcept
+      {
+	vector __tmp(get_allocator());
+	this->_M_impl._M_swap_data(__x._M_impl);
+	__tmp._M_impl._M_swap_data(__x._M_impl);
+	std::__alloc_on_move(_M_get_Tp_allocator(), __x._M_get_Tp_allocator());
+      }
+
+      // Do move assignment when it might not be possible to move source
+      // object's memory, resulting in a linear-time operation.
+      _GLIBCXX20_CONSTEXPR
+      void
+      _M_move_assign(vector&& __x, false_type)
+      {
+	if (__x._M_get_Tp_allocator() == this->_M_get_Tp_allocator())
+	  _M_move_assign(std::move(__x), true_type());
+	else
+	  {
+	    // The rvalue's allocator cannot be moved and is not equal,
+	    // so we need to individually move each element.
+	    this->_M_assign_aux(std::make_move_iterator(__x.begin()),
+			        std::make_move_iterator(__x.end()),
+				std::random_access_iterator_tag());
+	    __x.clear();
+	  }
+      }
+#endif
+
+      template<typename _Up>
+	_GLIBCXX20_CONSTEXPR
+	_Up*
+	_M_data_ptr(_Up* __ptr) const _GLIBCXX_NOEXCEPT
+	{ return __ptr; }
+
+#if __cplusplus >= 201103L
+      template<typename _Ptr>
+	_GLIBCXX20_CONSTEXPR
+	typename std::pointer_traits<_Ptr>::element_type*
+	_M_data_ptr(_Ptr __ptr) const
+	{ return empty() ? nullptr : std::__to_address(__ptr); }
+#else
+      template<typename _Up>
+	_Up*
+	_M_data_ptr(_Up* __ptr) _GLIBCXX_NOEXCEPT
+	{ return __ptr; }
+
+      template<typename _Ptr>
+	value_type*
+	_M_data_ptr(_Ptr __ptr)
+	{ return empty() ? (value_type*)0 : __ptr.operator->(); }
+
+      template<typename _Ptr>
+	const value_type*
+	_M_data_ptr(_Ptr __ptr) const
+	{ return empty() ? (const value_type*)0 : __ptr.operator->(); }
+#endif
+    };
+
+#if __cpp_deduction_guides >= 201606
+  template<typename _InputIterator, typename _ValT
+	     = typename iterator_traits<_InputIterator>::value_type,
+	   typename _Allocator = allocator<_ValT>,
+	   typename = _RequireInputIter<_InputIterator>,
+	   typename = _RequireAllocator<_Allocator>>
+    vector(_InputIterator, _InputIterator, _Allocator = _Allocator())
+      -> vector<_ValT, _Allocator>;
+#endif
+
+  /**
+   *  @brief  Vector equality comparison.
+   *  @param  __x  A %vector.
+   *  @param  __y  A %vector of the same type as @a __x.
+   *  @return  True iff the size and elements of the vectors are equal.
+   *
+   *  This is an equivalence relation.  It is linear in the size of the
+   *  vectors.  Vectors are considered equivalent if their sizes are equal,
+   *  and if corresponding elements compare equal.
+  */
+  template<typename _Tp, typename _Alloc>
+    _GLIBCXX20_CONSTEXPR
+    inline bool
+    operator==(const vector<_Tp, _Alloc>& __x, const vector<_Tp, _Alloc>& __y)
+    { return (__x.size() == __y.size()
+	      && std::equal(__x.begin(), __x.end(), __y.begin())); }
+
+#if __cpp_lib_three_way_comparison
+  /**
+   *  @brief  Vector ordering relation.
+   *  @param  __x  A `vector`.
+   *  @param  __y  A `vector` of the same type as `__x`.
+   *  @return  A value indicating whether `__x` is less than, equal to,
+   *           greater than, or incomparable with `__y`.
+   *
+   *  See `std::lexicographical_compare_three_way()` for how the determination
+   *  is made. This operator is used to synthesize relational operators like
+   *  `<` and `>=` etc.
+  */
+  template<typename _Tp, typename _Alloc>
+    _GLIBCXX20_CONSTEXPR
+    inline __detail::__synth3way_t<_Tp>
+    operator<=>(const vector<_Tp, _Alloc>& __x, const vector<_Tp, _Alloc>& __y)
+    {
+      return std::lexicographical_compare_three_way(__x.begin(), __x.end(),
+						    __y.begin(), __y.end(),
+						    __detail::__synth3way);
+    }
+#else
+  /**
+   *  @brief  Vector ordering relation.
+   *  @param  __x  A %vector.
+   *  @param  __y  A %vector of the same type as @a __x.
+   *  @return  True iff @a __x is lexicographically less than @a __y.
+   *
+   *  This is a total ordering relation.  It is linear in the size of the
+   *  vectors.  The elements must be comparable with @c <.
+   *
+   *  See std::lexicographical_compare() for how the determination is made.
+  */
+  template<typename _Tp, typename _Alloc>
+    inline bool
+    operator<(const vector<_Tp, _Alloc>& __x, const vector<_Tp, _Alloc>& __y)
+    { return std::lexicographical_compare(__x.begin(), __x.end(),
+					  __y.begin(), __y.end()); }
+
+  /// Based on operator==
+  template<typename _Tp, typename _Alloc>
+    inline bool
+    operator!=(const vector<_Tp, _Alloc>& __x, const vector<_Tp, _Alloc>& __y)
+    { return !(__x == __y); }
+
+  /// Based on operator<
+  template<typename _Tp, typename _Alloc>
+    inline bool
+    operator>(const vector<_Tp, _Alloc>& __x, const vector<_Tp, _Alloc>& __y)
+    { return __y < __x; }
+
+  /// Based on operator<
+  template<typename _Tp, typename _Alloc>
+    inline bool
+    operator<=(const vector<_Tp, _Alloc>& __x, const vector<_Tp, _Alloc>& __y)
+    { return !(__y < __x); }
+
+  /// Based on operator<
+  template<typename _Tp, typename _Alloc>
+    inline bool
+    operator>=(const vector<_Tp, _Alloc>& __x, const vector<_Tp, _Alloc>& __y)
+    { return !(__x < __y); }
+#endif // three-way comparison
+
+  /// See std::vector::swap().
+  template<typename _Tp, typename _Alloc>
+    _GLIBCXX20_CONSTEXPR
+    inline void
+    swap(vector<_Tp, _Alloc>& __x, vector<_Tp, _Alloc>& __y)
+    _GLIBCXX_NOEXCEPT_IF(noexcept(__x.swap(__y)))
+    { __x.swap(__y); }
+
+_GLIBCXX_END_NAMESPACE_CONTAINER
+
+#if __cplusplus >= 201703L
+  namespace __detail::__variant
+  {
+    template<typename> struct _Never_valueless_alt; // see <variant>
+
+    // Provide the strong exception-safety guarantee when emplacing a
+    // vector into a variant, but only if move assignment cannot throw.
+    template<typename _Tp, typename _Alloc>
+      struct _Never_valueless_alt<_GLIBCXX_STD_C::vector<_Tp, _Alloc>>
+      : std::is_nothrow_move_assignable<_GLIBCXX_STD_C::vector<_Tp, _Alloc>>
+      { };
+  }  // namespace __detail::__variant
+#endif // C++17
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif /* _STL_VECTOR_H */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stl_vector.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stl_vector.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stream_iterator.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stream_iterator.h
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stream_iterator.h
@@ -0,0 +1,270 @@
+// Stream iterators
+
+// Copyright (C) 2001-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/stream_iterator.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{iterator}
+ */
+
+#ifndef _STREAM_ITERATOR_H
+#define _STREAM_ITERATOR_H 1
+
+#pragma GCC system_header
+
+#include <debug/debug.h>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /**
+   * @addtogroup iterators
+   * @{
+   */
+
+// Ignore warnings about std::iterator.
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+
+  /// Provides input iterator semantics for streams.
+  template<typename _Tp, typename _CharT = char,
+           typename _Traits = char_traits<_CharT>, typename _Dist = ptrdiff_t>
+    class istream_iterator
+    : public iterator<input_iterator_tag, _Tp, _Dist, const _Tp*, const _Tp&>
+    {
+    public:
+      typedef _CharT                         char_type;
+      typedef _Traits                        traits_type;
+      typedef basic_istream<_CharT, _Traits> istream_type;
+
+    private:
+      istream_type*	_M_stream;
+      _Tp		_M_value;
+      // This bool becomes false at end-of-stream. It should be sufficient to
+      // check _M_stream != nullptr instead, but historically we did not set
+      // _M_stream to null when reaching the end, so we need to keep this flag.
+      bool		_M_ok;
+
+    public:
+      ///  Construct end of input stream iterator.
+      _GLIBCXX_CONSTEXPR istream_iterator()
+      _GLIBCXX_NOEXCEPT_IF(is_nothrow_default_constructible<_Tp>::value)
+      : _M_stream(0), _M_value(), _M_ok(false) {}
+
+      ///  Construct start of input stream iterator.
+      istream_iterator(istream_type& __s)
+      : _M_stream(std::__addressof(__s)), _M_ok(true)
+      { _M_read(); }
+
+      istream_iterator(const istream_iterator& __obj)
+      _GLIBCXX_NOEXCEPT_IF(is_nothrow_copy_constructible<_Tp>::value)
+      : _M_stream(__obj._M_stream), _M_value(__obj._M_value),
+        _M_ok(__obj._M_ok)
+      { }
+
+#if __cplusplus > 201703L && __cpp_lib_concepts
+      constexpr
+      istream_iterator(default_sentinel_t)
+      noexcept(is_nothrow_default_constructible_v<_Tp>)
+      : istream_iterator() { }
+#endif
+
+#if __cplusplus >= 201103L
+      istream_iterator& operator=(const istream_iterator&) = default;
+      ~istream_iterator() = default;
+#endif
+
+      _GLIBCXX_NODISCARD
+      const _Tp&
+      operator*() const _GLIBCXX_NOEXCEPT
+      {
+	__glibcxx_requires_cond(_M_ok,
+				_M_message(__gnu_debug::__msg_deref_istream)
+				._M_iterator(*this));
+	return _M_value;
+      }
+
+      _GLIBCXX_NODISCARD
+      const _Tp*
+      operator->() const _GLIBCXX_NOEXCEPT
+      { return std::__addressof((operator*())); }
+
+      istream_iterator&
+      operator++()
+      {
+	__glibcxx_requires_cond(_M_ok,
+				_M_message(__gnu_debug::__msg_inc_istream)
+				._M_iterator(*this));
+	_M_read();
+	return *this;
+      }
+
+      istream_iterator
+      operator++(int)
+      {
+	__glibcxx_requires_cond(_M_ok,
+				_M_message(__gnu_debug::__msg_inc_istream)
+				._M_iterator(*this));
+	istream_iterator __tmp = *this;
+	_M_read();
+	return __tmp;
+      }
+
+    private:
+      bool
+      _M_equal(const istream_iterator& __x) const _GLIBCXX_NOEXCEPT
+      {
+	// Ideally this would just return _M_stream == __x._M_stream,
+	// but code compiled with old versions never sets _M_stream to null.
+	return (_M_ok == __x._M_ok) && (!_M_ok || _M_stream == __x._M_stream);
+      }
+
+      void
+      _M_read()
+      {
+        if (_M_stream && !(*_M_stream >> _M_value))
+          {
+            _M_stream = 0;
+            _M_ok = false;
+          }
+      }
+
+      /// Return true if the iterators refer to the same stream,
+      /// or are both at end-of-stream.
+      _GLIBCXX_NODISCARD
+      friend bool
+      operator==(const istream_iterator& __x, const istream_iterator& __y)
+      _GLIBCXX_NOEXCEPT
+      { return __x._M_equal(__y); }
+
+#if __cpp_impl_three_way_comparison < 201907L
+      /// Return true if the iterators refer to different streams,
+      /// or if one is at end-of-stream and the other is not.
+      _GLIBCXX_NODISCARD
+      friend bool
+      operator!=(const istream_iterator& __x, const istream_iterator& __y)
+      _GLIBCXX_NOEXCEPT
+      { return !__x._M_equal(__y); }
+#endif
+
+#if __cplusplus > 201703L && __cpp_lib_concepts
+      [[nodiscard]]
+      friend bool
+      operator==(const istream_iterator& __i, default_sentinel_t) noexcept
+      { return !__i._M_stream; }
+#endif
+    };
+
+  /**
+   *  @brief  Provides output iterator semantics for streams.
+   *
+   *  This class provides an iterator to write to an ostream.  The type Tp is
+   *  the only type written by this iterator and there must be an
+   *  operator<<(Tp) defined.
+   *
+   *  @tparam  _Tp  The type to write to the ostream.
+   *  @tparam  _CharT  The ostream char_type.
+   *  @tparam  _Traits  The ostream char_traits.
+  */
+  template<typename _Tp, typename _CharT = char,
+           typename _Traits = char_traits<_CharT> >
+    class ostream_iterator
+    : public iterator<output_iterator_tag, void, void, void, void>
+    {
+    public:
+      ///@{
+      /// Public typedef
+#if __cplusplus > 201703L
+      using difference_type = ptrdiff_t;
+#endif
+      typedef _CharT                         char_type;
+      typedef _Traits                        traits_type;
+      typedef basic_ostream<_CharT, _Traits> ostream_type;
+      ///@}
+
+    private:
+      ostream_type*	_M_stream;
+      const _CharT*	_M_string;
+
+    public:
+      /// Construct from an ostream.
+      ostream_iterator(ostream_type& __s) _GLIBCXX_NOEXCEPT
+      : _M_stream(std::__addressof(__s)), _M_string(0) {}
+
+      /**
+       *  Construct from an ostream.
+       *
+       *  The delimiter string @a c is written to the stream after every Tp
+       *  written to the stream.  The delimiter is not copied, and thus must
+       *  not be destroyed while this iterator is in use.
+       *
+       *  @param  __s  Underlying ostream to write to.
+       *  @param  __c  CharT delimiter string to insert.
+      */
+      ostream_iterator(ostream_type& __s, const _CharT* __c) _GLIBCXX_NOEXCEPT
+      : _M_stream(std::__addressof(__s)), _M_string(__c)  { }
+
+      /// Copy constructor.
+      ostream_iterator(const ostream_iterator& __obj) _GLIBCXX_NOEXCEPT
+      : _M_stream(__obj._M_stream), _M_string(__obj._M_string)  { }
+
+#if __cplusplus >= 201103L
+      ostream_iterator& operator=(const ostream_iterator&) = default;
+#endif
+
+      /// Writes @a value to underlying ostream using operator<<.  If
+      /// constructed with delimiter string, writes delimiter to ostream.
+      ostream_iterator&
+      operator=(const _Tp& __value)
+      {
+	__glibcxx_requires_cond(_M_stream != 0,
+				_M_message(__gnu_debug::__msg_output_ostream)
+				._M_iterator(*this));
+	*_M_stream << __value;
+	if (_M_string)
+          *_M_stream << _M_string;
+	return *this;
+      }
+
+      _GLIBCXX_NODISCARD
+      ostream_iterator&
+      operator*() _GLIBCXX_NOEXCEPT
+      { return *this; }
+
+      ostream_iterator&
+      operator++() _GLIBCXX_NOEXCEPT
+      { return *this; }
+
+      ostream_iterator&
+      operator++(int) _GLIBCXX_NOEXCEPT
+      { return *this; }
+    };
+#pragma GCC diagnostic pop
+
+  /// @} group iterators
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif
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@@ -0,0 +1,169 @@
+// Stream buffer classes -*- C++ -*-
+
+// Copyright (C) 1997-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/streambuf.tcc
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{streambuf}
+ */
+
+//
+// ISO C++ 14882: 27.5  Stream buffers
+//
+
+#ifndef _STREAMBUF_TCC
+#define _STREAMBUF_TCC 1
+
+#pragma GCC system_header
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  template<typename _CharT, typename _Traits>
+    streamsize
+    basic_streambuf<_CharT, _Traits>::
+    xsgetn(char_type* __s, streamsize __n)
+    {
+      streamsize __ret = 0;
+      while (__ret < __n)
+	{
+	  const streamsize __buf_len = this->egptr() - this->gptr();
+	  if (__buf_len)
+	    {
+	      const streamsize __remaining = __n - __ret;
+	      const streamsize __len = std::min(__buf_len, __remaining);
+	      traits_type::copy(__s, this->gptr(), __len);
+	      __ret += __len;
+	      __s += __len;
+	      this->__safe_gbump(__len);
+	    }
+
+	  if (__ret < __n)
+	    {
+	      const int_type __c = this->uflow();
+	      if (!traits_type::eq_int_type(__c, traits_type::eof()))
+		{
+		  traits_type::assign(*__s++, traits_type::to_char_type(__c));
+		  ++__ret;
+		}
+	      else
+		break;
+	    }
+	}
+      return __ret;
+    }
+
+  template<typename _CharT, typename _Traits>
+    streamsize
+    basic_streambuf<_CharT, _Traits>::
+    xsputn(const char_type* __s, streamsize __n)
+    {
+      streamsize __ret = 0;
+      while (__ret < __n)
+	{
+	  const streamsize __buf_len = this->epptr() - this->pptr();
+	  if (__buf_len)
+	    {
+	      const streamsize __remaining = __n - __ret;
+	      const streamsize __len = std::min(__buf_len, __remaining);
+	      traits_type::copy(this->pptr(), __s, __len);
+	      __ret += __len;
+	      __s += __len;
+	      this->__safe_pbump(__len);
+	    }
+
+	  if (__ret < __n)
+	    {
+	      int_type __c = this->overflow(traits_type::to_int_type(*__s));
+	      if (!traits_type::eq_int_type(__c, traits_type::eof()))
+		{
+		  ++__ret;
+		  ++__s;
+		}
+	      else
+		break;
+	    }
+	}
+      return __ret;
+    }
+
+  // Conceivably, this could be used to implement buffer-to-buffer
+  // copies, if this was ever desired in an un-ambiguous way by the
+  // standard.
+  template<typename _CharT, typename _Traits>
+    streamsize
+    __copy_streambufs_eof(basic_streambuf<_CharT, _Traits>* __sbin,
+			  basic_streambuf<_CharT, _Traits>* __sbout,
+			  bool& __ineof)
+    {
+      streamsize __ret = 0;
+      __ineof = true;
+      typename _Traits::int_type __c = __sbin->sgetc();
+      while (!_Traits::eq_int_type(__c, _Traits::eof()))
+	{
+	  __c = __sbout->sputc(_Traits::to_char_type(__c));
+	  if (_Traits::eq_int_type(__c, _Traits::eof()))
+	    {
+	      __ineof = false;
+	      break;
+	    }
+	  ++__ret;
+	  __c = __sbin->snextc();
+	}
+      return __ret;
+    }
+
+  template<typename _CharT, typename _Traits>
+    inline streamsize
+    __copy_streambufs(basic_streambuf<_CharT, _Traits>* __sbin,
+		      basic_streambuf<_CharT, _Traits>* __sbout)
+    {
+      bool __ineof;
+      return __copy_streambufs_eof(__sbin, __sbout, __ineof);
+    }
+
+  // Inhibit implicit instantiations for required instantiations,
+  // which are defined via explicit instantiations elsewhere.
+#if _GLIBCXX_EXTERN_TEMPLATE
+  extern template class basic_streambuf<char>;
+
+  extern template
+    streamsize
+    __copy_streambufs(basic_streambuf<char>*,
+		      basic_streambuf<char>*);
+
+#ifdef _GLIBCXX_USE_WCHAR_T
+  extern template class basic_streambuf<wchar_t>;
+
+  extern template
+    streamsize
+    __copy_streambufs(basic_streambuf<wchar_t>*,
+		      basic_streambuf<wchar_t>*);
+#endif
+#endif
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@streambuf_iterator.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@streambuf_iterator.h
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@@ -0,0 +1,519 @@
+// Streambuf iterators
+
+// Copyright (C) 1997-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/streambuf_iterator.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{iterator}
+ */
+
+#ifndef _STREAMBUF_ITERATOR_H
+#define _STREAMBUF_ITERATOR_H 1
+
+#pragma GCC system_header
+
+#include <streambuf>
+#include <debug/debug.h>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /**
+   * @addtogroup iterators
+   * @{
+   */
+
+// Ignore warnings about std::iterator.
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+  // 24.5.3 Template class istreambuf_iterator
+  /// Provides input iterator semantics for streambufs.
+  template<typename _CharT, typename _Traits>
+    class istreambuf_iterator
+    : public iterator<input_iterator_tag, _CharT, typename _Traits::off_type,
+		      _CharT*, _CharT>
+    {
+    public:
+      // Types:
+      ///@{
+      /// Public typedefs
+#if __cplusplus < 201103L
+      typedef _CharT& reference; // Changed to _CharT by LWG 445
+#elif __cplusplus > 201703L
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 3188. istreambuf_iterator::pointer should not be unspecified
+      using pointer = void;
+#endif
+
+      typedef _CharT					char_type;
+      typedef _Traits					traits_type;
+      typedef typename _Traits::int_type		int_type;
+      typedef basic_streambuf<_CharT, _Traits>		streambuf_type;
+      typedef basic_istream<_CharT, _Traits>		istream_type;
+      ///@}
+
+      template<typename _CharT2>
+	friend typename __gnu_cxx::__enable_if<__is_char<_CharT2>::__value,
+				    ostreambuf_iterator<_CharT2> >::__type
+	copy(istreambuf_iterator<_CharT2>, istreambuf_iterator<_CharT2>,
+	     ostreambuf_iterator<_CharT2>);
+
+      template<bool _IsMove, typename _CharT2>
+	friend typename __gnu_cxx::__enable_if<__is_char<_CharT2>::__value,
+					       _CharT2*>::__type
+	__copy_move_a2(istreambuf_iterator<_CharT2>,
+		       istreambuf_iterator<_CharT2>, _CharT2*);
+
+      template<typename _CharT2, typename _Size>
+	friend typename __gnu_cxx::__enable_if<__is_char<_CharT2>::__value,
+					       _CharT2*>::__type
+	__copy_n_a(istreambuf_iterator<_CharT2>, _Size, _CharT2*, bool);
+
+      template<typename _CharT2>
+	friend typename __gnu_cxx::__enable_if<__is_char<_CharT2>::__value,
+				    istreambuf_iterator<_CharT2> >::__type
+	find(istreambuf_iterator<_CharT2>, istreambuf_iterator<_CharT2>,
+	     const _CharT2&);
+
+      template<typename _CharT2, typename _Distance>
+	friend typename __gnu_cxx::__enable_if<__is_char<_CharT2>::__value,
+					       void>::__type
+	advance(istreambuf_iterator<_CharT2>&, _Distance);
+
+    private:
+      // 24.5.3 istreambuf_iterator
+      // p 1
+      // If the end of stream is reached (streambuf_type::sgetc()
+      // returns traits_type::eof()), the iterator becomes equal to
+      // the "end of stream" iterator value.
+      // NB: This implementation assumes the "end of stream" value
+      // is EOF, or -1.
+      mutable streambuf_type*	_M_sbuf;
+      int_type			_M_c;
+
+    public:
+      ///  Construct end of input stream iterator.
+      _GLIBCXX_CONSTEXPR istreambuf_iterator() _GLIBCXX_USE_NOEXCEPT
+      : _M_sbuf(0), _M_c(traits_type::eof()) { }
+
+#if __cplusplus > 201703L && __cpp_lib_concepts
+      constexpr istreambuf_iterator(default_sentinel_t) noexcept
+      : istreambuf_iterator() { }
+#endif
+
+#if __cplusplus >= 201103L
+      istreambuf_iterator(const istreambuf_iterator&) noexcept = default;
+
+      ~istreambuf_iterator() = default;
+#endif
+
+      ///  Construct start of input stream iterator.
+      istreambuf_iterator(istream_type& __s) _GLIBCXX_USE_NOEXCEPT
+      : _M_sbuf(__s.rdbuf()), _M_c(traits_type::eof()) { }
+
+      ///  Construct start of streambuf iterator.
+      istreambuf_iterator(streambuf_type* __s) _GLIBCXX_USE_NOEXCEPT
+      : _M_sbuf(__s), _M_c(traits_type::eof()) { }
+
+#if __cplusplus >= 201103L
+      istreambuf_iterator&
+      operator=(const istreambuf_iterator&) noexcept = default;
+#endif
+
+      ///  Return the current character pointed to by iterator.  This returns
+      ///  streambuf.sgetc().  It cannot be assigned.  NB: The result of
+      ///  operator*() on an end of stream is undefined.
+      _GLIBCXX_NODISCARD
+      char_type
+      operator*() const
+      {
+	int_type __c = _M_get();
+
+#ifdef _GLIBCXX_DEBUG_PEDANTIC
+	// Dereferencing a past-the-end istreambuf_iterator is a
+	// libstdc++ extension
+	__glibcxx_requires_cond(!_S_is_eof(__c),
+				_M_message(__gnu_debug::__msg_deref_istreambuf)
+				._M_iterator(*this));
+#endif
+	return traits_type::to_char_type(__c);
+      }
+
+      /// Advance the iterator.  Calls streambuf.sbumpc().
+      istreambuf_iterator&
+      operator++()
+      {
+	__glibcxx_requires_cond(_M_sbuf &&
+				(!_S_is_eof(_M_c) || !_S_is_eof(_M_sbuf->sgetc())),
+				_M_message(__gnu_debug::__msg_inc_istreambuf)
+				._M_iterator(*this));
+
+	_M_sbuf->sbumpc();
+	_M_c = traits_type::eof();
+	return *this;
+      }
+
+      /// Advance the iterator.  Calls streambuf.sbumpc().
+      istreambuf_iterator
+      operator++(int)
+      {
+	__glibcxx_requires_cond(_M_sbuf &&
+				(!_S_is_eof(_M_c) || !_S_is_eof(_M_sbuf->sgetc())),
+				_M_message(__gnu_debug::__msg_inc_istreambuf)
+				._M_iterator(*this));
+
+	istreambuf_iterator __old = *this;
+	__old._M_c = _M_sbuf->sbumpc();
+	_M_c = traits_type::eof();
+	return __old;
+      }
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 110 istreambuf_iterator::equal not const
+      // NB: there is also number 111 (NAD) relevant to this function.
+      /// Return true both iterators are end or both are not end.
+      _GLIBCXX_NODISCARD
+      bool
+      equal(const istreambuf_iterator& __b) const
+      { return _M_at_eof() == __b._M_at_eof(); }
+
+    private:
+      int_type
+      _M_get() const
+      {
+	int_type __ret = _M_c;
+	if (_M_sbuf && _S_is_eof(__ret) && _S_is_eof(__ret = _M_sbuf->sgetc()))
+	  _M_sbuf = 0;
+	return __ret;
+      }
+
+      bool
+      _M_at_eof() const
+      { return _S_is_eof(_M_get()); }
+
+      static bool
+      _S_is_eof(int_type __c)
+      {
+	const int_type __eof = traits_type::eof();
+	return traits_type::eq_int_type(__c, __eof);
+      }
+
+#if __cplusplus > 201703L && __cpp_lib_concepts
+      [[nodiscard]]
+      friend bool
+      operator==(const istreambuf_iterator& __i, default_sentinel_t __s)
+      { return __i._M_at_eof(); }
+#endif
+    };
+
+  template<typename _CharT, typename _Traits>
+    _GLIBCXX_NODISCARD
+    inline bool
+    operator==(const istreambuf_iterator<_CharT, _Traits>& __a,
+	       const istreambuf_iterator<_CharT, _Traits>& __b)
+    { return __a.equal(__b); }
+
+#if __cpp_impl_three_way_comparison < 201907L
+  template<typename _CharT, typename _Traits>
+    _GLIBCXX_NODISCARD
+    inline bool
+    operator!=(const istreambuf_iterator<_CharT, _Traits>& __a,
+	       const istreambuf_iterator<_CharT, _Traits>& __b)
+    { return !__a.equal(__b); }
+#endif
+
+  /// Provides output iterator semantics for streambufs.
+  template<typename _CharT, typename _Traits>
+    class ostreambuf_iterator
+    : public iterator<output_iterator_tag, void, void, void, void>
+    {
+    public:
+      // Types:
+      ///@{
+      /// Public typedefs
+#if __cplusplus > 201703L
+      using difference_type = ptrdiff_t;
+#endif
+      typedef _CharT			       char_type;
+      typedef _Traits			       traits_type;
+      typedef basic_streambuf<_CharT, _Traits> streambuf_type;
+      typedef basic_ostream<_CharT, _Traits>   ostream_type;
+      ///@}
+
+      template<typename _CharT2>
+	friend typename __gnu_cxx::__enable_if<__is_char<_CharT2>::__value,
+				    ostreambuf_iterator<_CharT2> >::__type
+	copy(istreambuf_iterator<_CharT2>, istreambuf_iterator<_CharT2>,
+	     ostreambuf_iterator<_CharT2>);
+
+    private:
+      streambuf_type*	_M_sbuf;
+      bool		_M_failed;
+
+    public:
+
+#if __cplusplus > 201703L
+      constexpr
+      ostreambuf_iterator() noexcept
+      : _M_sbuf(nullptr), _M_failed(true) { }
+#endif
+
+      ///  Construct output iterator from ostream.
+      ostreambuf_iterator(ostream_type& __s) _GLIBCXX_USE_NOEXCEPT
+      : _M_sbuf(__s.rdbuf()), _M_failed(!_M_sbuf) { }
+
+      ///  Construct output iterator from streambuf.
+      ostreambuf_iterator(streambuf_type* __s) _GLIBCXX_USE_NOEXCEPT
+      : _M_sbuf(__s), _M_failed(!_M_sbuf) { }
+
+      ///  Write character to streambuf.  Calls streambuf.sputc().
+      ostreambuf_iterator&
+      operator=(_CharT __c)
+      {
+	if (!_M_failed &&
+	    _Traits::eq_int_type(_M_sbuf->sputc(__c), _Traits::eof()))
+	  _M_failed = true;
+	return *this;
+      }
+
+      /// Return *this.
+      _GLIBCXX_NODISCARD
+      ostreambuf_iterator&
+      operator*()
+      { return *this; }
+
+      /// Return *this.
+      ostreambuf_iterator&
+      operator++(int)
+      { return *this; }
+
+      /// Return *this.
+      ostreambuf_iterator&
+      operator++()
+      { return *this; }
+
+      /// Return true if previous operator=() failed.
+      _GLIBCXX_NODISCARD
+      bool
+      failed() const _GLIBCXX_USE_NOEXCEPT
+      { return _M_failed; }
+
+      ostreambuf_iterator&
+      _M_put(const _CharT* __ws, streamsize __len)
+      {
+	if (__builtin_expect(!_M_failed, true)
+	    && __builtin_expect(this->_M_sbuf->sputn(__ws, __len) != __len,
+				false))
+	  _M_failed = true;
+	return *this;
+      }
+    };
+#pragma GCC diagnostic pop
+
+  // Overloads for streambuf iterators.
+  template<typename _CharT>
+    typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
+				    ostreambuf_iterator<_CharT> >::__type
+    copy(istreambuf_iterator<_CharT> __first,
+	 istreambuf_iterator<_CharT> __last,
+	 ostreambuf_iterator<_CharT> __result)
+    {
+      if (__first._M_sbuf && !__last._M_sbuf && !__result._M_failed)
+	{
+	  bool __ineof;
+	  __copy_streambufs_eof(__first._M_sbuf, __result._M_sbuf, __ineof);
+	  if (!__ineof)
+	    __result._M_failed = true;
+	}
+      return __result;
+    }
+
+  template<bool _IsMove, typename _CharT>
+    typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
+				    ostreambuf_iterator<_CharT> >::__type
+    __copy_move_a2(_CharT* __first, _CharT* __last,
+		   ostreambuf_iterator<_CharT> __result)
+    {
+      const streamsize __num = __last - __first;
+      if (__num > 0)
+	__result._M_put(__first, __num);
+      return __result;
+    }
+
+  template<bool _IsMove, typename _CharT>
+    typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
+				    ostreambuf_iterator<_CharT> >::__type
+    __copy_move_a2(const _CharT* __first, const _CharT* __last,
+		   ostreambuf_iterator<_CharT> __result)
+    {
+      const streamsize __num = __last - __first;
+      if (__num > 0)
+	__result._M_put(__first, __num);
+      return __result;
+    }
+
+  template<bool _IsMove, typename _CharT>
+    typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
+				    _CharT*>::__type
+    __copy_move_a2(istreambuf_iterator<_CharT> __first,
+		   istreambuf_iterator<_CharT> __last, _CharT* __result)
+    {
+      typedef istreambuf_iterator<_CharT>		   __is_iterator_type;
+      typedef typename __is_iterator_type::traits_type	   traits_type;
+      typedef typename __is_iterator_type::streambuf_type  streambuf_type;
+      typedef typename traits_type::int_type		   int_type;
+
+      if (__first._M_sbuf && !__last._M_sbuf)
+	{
+	  streambuf_type* __sb = __first._M_sbuf;
+	  int_type __c = __sb->sgetc();
+	  while (!traits_type::eq_int_type(__c, traits_type::eof()))
+	    {
+	      const streamsize __n = __sb->egptr() - __sb->gptr();
+	      if (__n > 1)
+		{
+		  traits_type::copy(__result, __sb->gptr(), __n);
+		  __sb->__safe_gbump(__n);
+		  __result += __n;
+		  __c = __sb->underflow();
+		}
+	      else
+		{
+		  *__result++ = traits_type::to_char_type(__c);
+		  __c = __sb->snextc();
+		}
+	    }
+	}
+      return __result;
+    }
+
+  template<typename _CharT, typename _Size>
+    typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
+				    _CharT*>::__type
+    __copy_n_a(istreambuf_iterator<_CharT> __it, _Size __n, _CharT* __result,
+	       bool __strict __attribute__((__unused__)))
+    {
+      if (__n == 0)
+	return __result;
+
+      __glibcxx_requires_cond(__it._M_sbuf,
+			      _M_message(__gnu_debug::__msg_inc_istreambuf)
+			      ._M_iterator(__it));
+      _CharT* __beg = __result;
+      __result += __it._M_sbuf->sgetn(__beg, __n);
+      __glibcxx_requires_cond(!__strict || __result - __beg == __n,
+			      _M_message(__gnu_debug::__msg_inc_istreambuf)
+			      ._M_iterator(__it));
+      return __result;
+    }
+
+  template<typename _CharT>
+    typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
+		  		    istreambuf_iterator<_CharT> >::__type
+    find(istreambuf_iterator<_CharT> __first,
+	 istreambuf_iterator<_CharT> __last, const _CharT& __val)
+    {
+      typedef istreambuf_iterator<_CharT>		   __is_iterator_type;
+      typedef typename __is_iterator_type::traits_type     traits_type;
+      typedef typename __is_iterator_type::streambuf_type  streambuf_type;
+      typedef typename traits_type::int_type		   int_type;
+      const int_type __eof = traits_type::eof();
+
+      if (__first._M_sbuf && !__last._M_sbuf)
+	{
+	  const int_type __ival = traits_type::to_int_type(__val);
+	  streambuf_type* __sb = __first._M_sbuf;
+	  int_type __c = __sb->sgetc();
+	  while (!traits_type::eq_int_type(__c, __eof)
+		 && !traits_type::eq_int_type(__c, __ival))
+	    {
+	      streamsize __n = __sb->egptr() - __sb->gptr();
+	      if (__n > 1)
+		{
+		  const _CharT* __p = traits_type::find(__sb->gptr(),
+							__n, __val);
+		  if (__p)
+		    __n = __p - __sb->gptr();
+		  __sb->__safe_gbump(__n);
+		  __c = __sb->sgetc();
+		}
+	      else
+		__c = __sb->snextc();
+	    }
+
+	  __first._M_c = __eof;
+	}
+
+      return __first;
+    }
+
+  template<typename _CharT, typename _Distance>
+    typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
+				    void>::__type
+    advance(istreambuf_iterator<_CharT>& __i, _Distance __n)
+    {
+      if (__n == 0)
+	return;
+
+      __glibcxx_assert(__n > 0);
+      __glibcxx_requires_cond(!__i._M_at_eof(),
+			      _M_message(__gnu_debug::__msg_inc_istreambuf)
+			      ._M_iterator(__i));
+
+      typedef istreambuf_iterator<_CharT>		   __is_iterator_type;
+      typedef typename __is_iterator_type::traits_type	   traits_type;
+      typedef typename __is_iterator_type::streambuf_type  streambuf_type;
+      typedef typename traits_type::int_type		   int_type;
+      const int_type __eof = traits_type::eof();
+
+      streambuf_type* __sb = __i._M_sbuf;
+      while (__n > 0)
+	{
+	  streamsize __size = __sb->egptr() - __sb->gptr();
+	  if (__size > __n)
+	    {
+	      __sb->__safe_gbump(__n);
+	      break;
+	    }
+
+	  __sb->__safe_gbump(__size);
+	  __n -= __size;
+	  if (traits_type::eq_int_type(__sb->underflow(), __eof))
+	    {
+	      __glibcxx_requires_cond(__n == 0,
+				_M_message(__gnu_debug::__msg_inc_istreambuf)
+				._M_iterator(__i));
+	      break;
+	    }
+	}
+
+      __i._M_c = __eof;
+    }
+
+/// @} group iterators
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stringfwd.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stringfwd.h
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@stringfwd.h
@@ -0,0 +1,100 @@
+// <string> Forward declarations -*- C++ -*-
+
+// Copyright (C) 2001-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/stringfwd.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{string}
+ */
+
+//
+// ISO C++ 14882: 21 Strings library
+//
+
+#ifndef _STRINGFWD_H
+#define _STRINGFWD_H 1
+
+#pragma GCC system_header
+
+#include <bits/c++config.h>
+#include <bits/memoryfwd.h>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /**
+   *  @defgroup strings Strings
+   *
+   *  @{
+  */
+
+  template<class _CharT>
+    struct char_traits;
+
+  template<> struct char_traits<char>;
+
+  template<> struct char_traits<wchar_t>;
+
+#ifdef _GLIBCXX_USE_CHAR8_T
+  template<> struct char_traits<char8_t>;
+#endif
+
+#if __cplusplus >= 201103L
+  template<> struct char_traits<char16_t>;
+  template<> struct char_traits<char32_t>;
+#endif
+
+_GLIBCXX_BEGIN_NAMESPACE_CXX11
+
+  template<typename _CharT, typename _Traits = char_traits<_CharT>,
+           typename _Alloc = allocator<_CharT> >
+    class basic_string;
+
+_GLIBCXX_END_NAMESPACE_CXX11
+
+  /// A string of @c char
+  typedef basic_string<char>    string;   
+
+  /// A string of @c wchar_t
+  typedef basic_string<wchar_t> wstring;   
+
+#ifdef _GLIBCXX_USE_CHAR8_T
+  /// A string of @c char8_t
+  typedef basic_string<char8_t> u8string;
+#endif
+
+#if __cplusplus >= 201103L
+  /// A string of @c char16_t
+  typedef basic_string<char16_t> u16string; 
+
+  /// A string of @c char32_t
+  typedef basic_string<char32_t> u32string; 
+#endif
+
+  /** @}  */
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif	// _STRINGFWD_H
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@this_thread_sleep.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@this_thread_sleep.h
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@this_thread_sleep.h
@@ -0,0 +1,117 @@
+// std::this_thread::sleep_for/until declarations -*- C++ -*-
+
+// Copyright (C) 2008-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/this_thread_sleep.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{thread}
+ */
+
+#ifndef _GLIBCXX_THIS_THREAD_SLEEP_H
+#define _GLIBCXX_THIS_THREAD_SLEEP_H 1
+
+#pragma GCC system_header
+
+#if __cplusplus >= 201103L
+#include <bits/chrono.h> // std::chrono::*
+
+#ifdef _GLIBCXX_USE_NANOSLEEP
+# include <cerrno>  // errno, EINTR
+# include <time.h>  // nanosleep
+#endif
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /** @addtogroup threads
+   *  @{
+   */
+
+  /** @namespace std::this_thread
+   *  @brief ISO C++ 2011 namespace for interacting with the current thread
+   *
+   *  C++11 30.3.2 [thread.thread.this] Namespace this_thread.
+   */
+  namespace this_thread
+  {
+#ifndef _GLIBCXX_NO_SLEEP
+
+#ifndef _GLIBCXX_USE_NANOSLEEP
+    void
+    __sleep_for(chrono::seconds, chrono::nanoseconds);
+#endif
+
+    /// this_thread::sleep_for
+    template<typename _Rep, typename _Period>
+      inline void
+      sleep_for(const chrono::duration<_Rep, _Period>& __rtime)
+      {
+	if (__rtime <= __rtime.zero())
+	  return;
+	auto __s = chrono::duration_cast<chrono::seconds>(__rtime);
+	auto __ns = chrono::duration_cast<chrono::nanoseconds>(__rtime - __s);
+#ifdef _GLIBCXX_USE_NANOSLEEP
+	struct ::timespec __ts =
+	  {
+	    static_cast<std::time_t>(__s.count()),
+	    static_cast<long>(__ns.count())
+	  };
+	while (::nanosleep(&__ts, &__ts) == -1 && errno == EINTR)
+	  { }
+#else
+	__sleep_for(__s, __ns);
+#endif
+      }
+
+    /// this_thread::sleep_until
+    template<typename _Clock, typename _Duration>
+      inline void
+      sleep_until(const chrono::time_point<_Clock, _Duration>& __atime)
+      {
+#if __cplusplus > 201703L
+	static_assert(chrono::is_clock_v<_Clock>);
+#endif
+	auto __now = _Clock::now();
+	if (_Clock::is_steady)
+	  {
+	    if (__now < __atime)
+	      sleep_for(__atime - __now);
+	    return;
+	  }
+	while (__now < __atime)
+	  {
+	    sleep_for(__atime - __now);
+	    __now = _Clock::now();
+	  }
+      }
+#endif // ! NO_SLEEP
+  } // namespace this_thread
+
+  /// @}
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+#endif // C++11
+
+#endif // _GLIBCXX_THIS_THREAD_SLEEP_H
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@uniform_int_dist.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@uniform_int_dist.h
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@@ -0,0 +1,457 @@
+// Class template uniform_int_distribution -*- C++ -*-
+
+// Copyright (C) 2009-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/**
+ * @file bits/uniform_int_dist.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{random}
+ */
+
+#ifndef _GLIBCXX_BITS_UNIFORM_INT_DIST_H
+#define _GLIBCXX_BITS_UNIFORM_INT_DIST_H
+
+#include <type_traits>
+#include <ext/numeric_traits.h>
+#if __cplusplus > 201703L
+# include <concepts>
+#endif
+#include <bits/concept_check.h> // __glibcxx_function_requires
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+#ifdef __cpp_lib_concepts
+  /// Requirements for a uniform random bit generator.
+  template<typename _Gen>
+    concept uniform_random_bit_generator
+      = invocable<_Gen&> && unsigned_integral<invoke_result_t<_Gen&>>
+      && requires
+      {
+	{ _Gen::min() } -> same_as<invoke_result_t<_Gen&>>;
+	{ _Gen::max() } -> same_as<invoke_result_t<_Gen&>>;
+	requires bool_constant<(_Gen::min() < _Gen::max())>::value;
+      };
+#endif
+
+  namespace __detail
+  {
+    // Determine whether number is a power of two.
+    // This is true for zero, which is OK because we want _Power_of_2(n+1)
+    // to be true if n==numeric_limits<_Tp>::max() and so n+1 wraps around.
+    template<typename _Tp>
+      constexpr bool
+      _Power_of_2(_Tp __x)
+      {
+	return ((__x - 1) & __x) == 0;
+      }
+  }
+
+  /**
+   * @brief Uniform discrete distribution for random numbers.
+   * A discrete random distribution on the range @f$[min, max]@f$ with equal
+   * probability throughout the range.
+   */
+  template<typename _IntType = int>
+    class uniform_int_distribution
+    {
+      static_assert(std::is_integral<_IntType>::value,
+		    "template argument must be an integral type");
+
+    public:
+      /** The type of the range of the distribution. */
+      typedef _IntType result_type;
+      /** Parameter type. */
+      struct param_type
+      {
+	typedef uniform_int_distribution<_IntType> distribution_type;
+
+	param_type() : param_type(0) { }
+
+	explicit
+	param_type(_IntType __a,
+		   _IntType __b = __gnu_cxx::__int_traits<_IntType>::__max)
+	: _M_a(__a), _M_b(__b)
+	{
+	  __glibcxx_assert(_M_a <= _M_b);
+	}
+
+	result_type
+	a() const
+	{ return _M_a; }
+
+	result_type
+	b() const
+	{ return _M_b; }
+
+	friend bool
+	operator==(const param_type& __p1, const param_type& __p2)
+	{ return __p1._M_a == __p2._M_a && __p1._M_b == __p2._M_b; }
+
+	friend bool
+	operator!=(const param_type& __p1, const param_type& __p2)
+	{ return !(__p1 == __p2); }
+
+      private:
+	_IntType _M_a;
+	_IntType _M_b;
+      };
+
+    public:
+      /**
+       * @brief Constructs a uniform distribution object.
+       */
+      uniform_int_distribution() : uniform_int_distribution(0) { }
+
+      /**
+       * @brief Constructs a uniform distribution object.
+       */
+      explicit
+      uniform_int_distribution(_IntType __a,
+			       _IntType __b
+				 = __gnu_cxx::__int_traits<_IntType>::__max)
+      : _M_param(__a, __b)
+      { }
+
+      explicit
+      uniform_int_distribution(const param_type& __p)
+      : _M_param(__p)
+      { }
+
+      /**
+       * @brief Resets the distribution state.
+       *
+       * Does nothing for the uniform integer distribution.
+       */
+      void
+      reset() { }
+
+      result_type
+      a() const
+      { return _M_param.a(); }
+
+      result_type
+      b() const
+      { return _M_param.b(); }
+
+      /**
+       * @brief Returns the parameter set of the distribution.
+       */
+      param_type
+      param() const
+      { return _M_param; }
+
+      /**
+       * @brief Sets the parameter set of the distribution.
+       * @param __param The new parameter set of the distribution.
+       */
+      void
+      param(const param_type& __param)
+      { _M_param = __param; }
+
+      /**
+       * @brief Returns the inclusive lower bound of the distribution range.
+       */
+      result_type
+      min() const
+      { return this->a(); }
+
+      /**
+       * @brief Returns the inclusive upper bound of the distribution range.
+       */
+      result_type
+      max() const
+      { return this->b(); }
+
+      /**
+       * @brief Generating functions.
+       */
+      template<typename _UniformRandomBitGenerator>
+	result_type
+	operator()(_UniformRandomBitGenerator& __urng)
+        { return this->operator()(__urng, _M_param); }
+
+      template<typename _UniformRandomBitGenerator>
+	result_type
+	operator()(_UniformRandomBitGenerator& __urng,
+		   const param_type& __p);
+
+      template<typename _ForwardIterator,
+	       typename _UniformRandomBitGenerator>
+	void
+	__generate(_ForwardIterator __f, _ForwardIterator __t,
+		   _UniformRandomBitGenerator& __urng)
+	{ this->__generate(__f, __t, __urng, _M_param); }
+
+      template<typename _ForwardIterator,
+	       typename _UniformRandomBitGenerator>
+	void
+	__generate(_ForwardIterator __f, _ForwardIterator __t,
+		   _UniformRandomBitGenerator& __urng,
+		   const param_type& __p)
+	{ this->__generate_impl(__f, __t, __urng, __p); }
+
+      template<typename _UniformRandomBitGenerator>
+	void
+	__generate(result_type* __f, result_type* __t,
+		   _UniformRandomBitGenerator& __urng,
+		   const param_type& __p)
+	{ this->__generate_impl(__f, __t, __urng, __p); }
+
+      /**
+       * @brief Return true if two uniform integer distributions have
+       *        the same parameters.
+       */
+      friend bool
+      operator==(const uniform_int_distribution& __d1,
+		 const uniform_int_distribution& __d2)
+      { return __d1._M_param == __d2._M_param; }
+
+    private:
+      template<typename _ForwardIterator,
+	       typename _UniformRandomBitGenerator>
+	void
+	__generate_impl(_ForwardIterator __f, _ForwardIterator __t,
+			_UniformRandomBitGenerator& __urng,
+			const param_type& __p);
+
+      param_type _M_param;
+
+      // Lemire's nearly divisionless algorithm.
+      // Returns an unbiased random number from __g downscaled to [0,__range)
+      // using an unsigned type _Wp twice as wide as unsigned type _Up.
+      template<typename _Wp, typename _Urbg, typename _Up>
+	static _Up
+	_S_nd(_Urbg& __g, _Up __range)
+	{
+	  using _Up_traits = __gnu_cxx::__int_traits<_Up>;
+	  using _Wp_traits = __gnu_cxx::__int_traits<_Wp>;
+	  static_assert(!_Up_traits::__is_signed, "U must be unsigned");
+	  static_assert(!_Wp_traits::__is_signed, "W must be unsigned");
+	  static_assert(_Wp_traits::__digits == (2 * _Up_traits::__digits),
+			"W must be twice as wide as U");
+
+	  // reference: Fast Random Integer Generation in an Interval
+	  // ACM Transactions on Modeling and Computer Simulation 29 (1), 2019
+	  // https://arxiv.org/abs/1805.10941
+	  _Wp __product = _Wp(__g()) * _Wp(__range);
+	  _Up __low = _Up(__product);
+	  if (__low < __range)
+	    {
+	      _Up __threshold = -__range % __range;
+	      while (__low < __threshold)
+		{
+		  __product = _Wp(__g()) * _Wp(__range);
+		  __low = _Up(__product);
+		}
+	    }
+	  return __product >> _Up_traits::__digits;
+	}
+    };
+
+  template<typename _IntType>
+    template<typename _UniformRandomBitGenerator>
+      typename uniform_int_distribution<_IntType>::result_type
+      uniform_int_distribution<_IntType>::
+      operator()(_UniformRandomBitGenerator& __urng,
+		 const param_type& __param)
+      {
+	typedef typename _UniformRandomBitGenerator::result_type _Gresult_type;
+	typedef typename make_unsigned<result_type>::type __utype;
+	typedef typename common_type<_Gresult_type, __utype>::type __uctype;
+
+	constexpr __uctype __urngmin = _UniformRandomBitGenerator::min();
+	constexpr __uctype __urngmax = _UniformRandomBitGenerator::max();
+	static_assert( __urngmin < __urngmax,
+	    "Uniform random bit generator must define min() < max()");
+	constexpr __uctype __urngrange = __urngmax - __urngmin;
+
+	const __uctype __urange
+	  = __uctype(__param.b()) - __uctype(__param.a());
+
+	__uctype __ret;
+	if (__urngrange > __urange)
+	  {
+	    // downscaling
+
+	    const __uctype __uerange = __urange + 1; // __urange can be zero
+
+#if defined __UINT64_TYPE__ && defined __UINT32_TYPE__
+#if __SIZEOF_INT128__
+	    if _GLIBCXX17_CONSTEXPR (__urngrange == __UINT64_MAX__)
+	      {
+		// __urng produces values that use exactly 64-bits,
+		// so use 128-bit integers to downscale to desired range.
+		__UINT64_TYPE__ __u64erange = __uerange;
+		__ret = __extension__ _S_nd<unsigned __int128>(__urng,
+							       __u64erange);
+	      }
+	    else
+#endif
+	    if _GLIBCXX17_CONSTEXPR (__urngrange == __UINT32_MAX__)
+	      {
+		// __urng produces values that use exactly 32-bits,
+		// so use 64-bit integers to downscale to desired range.
+		__UINT32_TYPE__ __u32erange = __uerange;
+		__ret = _S_nd<__UINT64_TYPE__>(__urng, __u32erange);
+	      }
+	    else
+#endif
+	      {
+		// fallback case (2 divisions)
+		const __uctype __scaling = __urngrange / __uerange;
+		const __uctype __past = __uerange * __scaling;
+		do
+		  __ret = __uctype(__urng()) - __urngmin;
+		while (__ret >= __past);
+		__ret /= __scaling;
+	      }
+	  }
+	else if (__urngrange < __urange)
+	  {
+	    // upscaling
+	    /*
+	      Note that every value in [0, urange]
+	      can be written uniquely as
+
+	      (urngrange + 1) * high + low
+
+	      where
+
+	      high in [0, urange / (urngrange + 1)]
+
+	      and
+
+	      low in [0, urngrange].
+	    */
+	    __uctype __tmp; // wraparound control
+	    do
+	      {
+		const __uctype __uerngrange = __urngrange + 1;
+		__tmp = (__uerngrange * operator()
+			 (__urng, param_type(0, __urange / __uerngrange)));
+		__ret = __tmp + (__uctype(__urng()) - __urngmin);
+	      }
+	    while (__ret > __urange || __ret < __tmp);
+	  }
+	else
+	  __ret = __uctype(__urng()) - __urngmin;
+
+	return __ret + __param.a();
+      }
+
+
+  template<typename _IntType>
+    template<typename _ForwardIterator,
+	     typename _UniformRandomBitGenerator>
+      void
+      uniform_int_distribution<_IntType>::
+      __generate_impl(_ForwardIterator __f, _ForwardIterator __t,
+		      _UniformRandomBitGenerator& __urng,
+		      const param_type& __param)
+      {
+	__glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+	typedef typename _UniformRandomBitGenerator::result_type _Gresult_type;
+	typedef typename make_unsigned<result_type>::type __utype;
+	typedef typename common_type<_Gresult_type, __utype>::type __uctype;
+
+	static_assert( __urng.min() < __urng.max(),
+	    "Uniform random bit generator must define min() < max()");
+
+	constexpr __uctype __urngmin = __urng.min();
+	constexpr __uctype __urngmax = __urng.max();
+	constexpr __uctype __urngrange = __urngmax - __urngmin;
+	const __uctype __urange
+	  = __uctype(__param.b()) - __uctype(__param.a());
+
+	__uctype __ret;
+
+	if (__urngrange > __urange)
+	  {
+	    if (__detail::_Power_of_2(__urngrange + 1)
+		&& __detail::_Power_of_2(__urange + 1))
+	      {
+		while (__f != __t)
+		  {
+		    __ret = __uctype(__urng()) - __urngmin;
+		    *__f++ = (__ret & __urange) + __param.a();
+		  }
+	      }
+	    else
+	      {
+		// downscaling
+		const __uctype __uerange = __urange + 1; // __urange can be zero
+		const __uctype __scaling = __urngrange / __uerange;
+		const __uctype __past = __uerange * __scaling;
+		while (__f != __t)
+		  {
+		    do
+		      __ret = __uctype(__urng()) - __urngmin;
+		    while (__ret >= __past);
+		    *__f++ = __ret / __scaling + __param.a();
+		  }
+	      }
+	  }
+	else if (__urngrange < __urange)
+	  {
+	    // upscaling
+	    /*
+	      Note that every value in [0, urange]
+	      can be written uniquely as
+
+	      (urngrange + 1) * high + low
+
+	      where
+
+	      high in [0, urange / (urngrange + 1)]
+
+	      and
+
+	      low in [0, urngrange].
+	    */
+	    __uctype __tmp; // wraparound control
+	    while (__f != __t)
+	      {
+		do
+		  {
+		    constexpr __uctype __uerngrange = __urngrange + 1;
+		    __tmp = (__uerngrange * operator()
+			     (__urng, param_type(0, __urange / __uerngrange)));
+		    __ret = __tmp + (__uctype(__urng()) - __urngmin);
+		  }
+		while (__ret > __urange || __ret < __tmp);
+		*__f++ = __ret;
+	      }
+	  }
+	else
+	  while (__f != __t)
+	    *__f++ = __uctype(__urng()) - __urngmin + __param.a();
+      }
+
+  // operator!= and operator<< and operator>> are defined in <bits/random.h>
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@uniform_int_dist.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@uniform_int_dist.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@unique_lock.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@unique_lock.h
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--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@unique_lock.h
@@ -0,0 +1,243 @@
+// std::unique_lock implementation -*- C++ -*-
+
+// Copyright (C) 2008-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/unique_lock.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{mutex}
+ */
+
+#ifndef _GLIBCXX_UNIQUE_LOCK_H
+#define _GLIBCXX_UNIQUE_LOCK_H 1
+
+#pragma GCC system_header
+
+#if __cplusplus < 201103L
+# include <bits/c++0x_warning.h>
+#else
+
+#include <bits/chrono.h>
+#include <bits/move.h> // for std::swap
+#include <bits/std_mutex.h> // for std::defer_lock_t
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /** @brief A movable scoped lock type.
+   *
+   * A unique_lock controls mutex ownership within a scope. Ownership of the
+   * mutex can be delayed until after construction and can be transferred
+   * to another unique_lock by move construction or move assignment. If a
+   * mutex lock is owned when the destructor runs ownership will be released.
+   *
+   * @ingroup mutexes
+   */
+  template<typename _Mutex>
+    class unique_lock
+    {
+    public:
+      typedef _Mutex mutex_type;
+
+      unique_lock() noexcept
+      : _M_device(0), _M_owns(false)
+      { }
+
+      explicit unique_lock(mutex_type& __m)
+      : _M_device(std::__addressof(__m)), _M_owns(false)
+      {
+	lock();
+	_M_owns = true;
+      }
+
+      unique_lock(mutex_type& __m, defer_lock_t) noexcept
+      : _M_device(std::__addressof(__m)), _M_owns(false)
+      { }
+
+      unique_lock(mutex_type& __m, try_to_lock_t)
+      : _M_device(std::__addressof(__m)), _M_owns(_M_device->try_lock())
+      { }
+
+      unique_lock(mutex_type& __m, adopt_lock_t) noexcept
+      : _M_device(std::__addressof(__m)), _M_owns(true)
+      {
+	// XXX calling thread owns mutex
+      }
+
+      template<typename _Clock, typename _Duration>
+	unique_lock(mutex_type& __m,
+		    const chrono::time_point<_Clock, _Duration>& __atime)
+	: _M_device(std::__addressof(__m)),
+	  _M_owns(_M_device->try_lock_until(__atime))
+	{ }
+
+      template<typename _Rep, typename _Period>
+	unique_lock(mutex_type& __m,
+		    const chrono::duration<_Rep, _Period>& __rtime)
+	: _M_device(std::__addressof(__m)),
+	  _M_owns(_M_device->try_lock_for(__rtime))
+	{ }
+
+      ~unique_lock()
+      {
+	if (_M_owns)
+	  unlock();
+      }
+
+      unique_lock(const unique_lock&) = delete;
+      unique_lock& operator=(const unique_lock&) = delete;
+
+      unique_lock(unique_lock&& __u) noexcept
+      : _M_device(__u._M_device), _M_owns(__u._M_owns)
+      {
+	__u._M_device = 0;
+	__u._M_owns = false;
+      }
+
+      unique_lock& operator=(unique_lock&& __u) noexcept
+      {
+	if(_M_owns)
+	  unlock();
+
+	unique_lock(std::move(__u)).swap(*this);
+
+	__u._M_device = 0;
+	__u._M_owns = false;
+
+	return *this;
+      }
+
+      void
+      lock()
+      {
+	if (!_M_device)
+	  __throw_system_error(int(errc::operation_not_permitted));
+	else if (_M_owns)
+	  __throw_system_error(int(errc::resource_deadlock_would_occur));
+	else
+	  {
+	    _M_device->lock();
+	    _M_owns = true;
+	  }
+      }
+
+      bool
+      try_lock()
+      {
+	if (!_M_device)
+	  __throw_system_error(int(errc::operation_not_permitted));
+	else if (_M_owns)
+	  __throw_system_error(int(errc::resource_deadlock_would_occur));
+	else
+	  {
+	    _M_owns = _M_device->try_lock();
+	    return _M_owns;
+	  }
+      }
+
+      template<typename _Clock, typename _Duration>
+	bool
+	try_lock_until(const chrono::time_point<_Clock, _Duration>& __atime)
+	{
+	  if (!_M_device)
+	    __throw_system_error(int(errc::operation_not_permitted));
+	  else if (_M_owns)
+	    __throw_system_error(int(errc::resource_deadlock_would_occur));
+	  else
+	    {
+	      _M_owns = _M_device->try_lock_until(__atime);
+	      return _M_owns;
+	    }
+	}
+
+      template<typename _Rep, typename _Period>
+	bool
+	try_lock_for(const chrono::duration<_Rep, _Period>& __rtime)
+	{
+	  if (!_M_device)
+	    __throw_system_error(int(errc::operation_not_permitted));
+	  else if (_M_owns)
+	    __throw_system_error(int(errc::resource_deadlock_would_occur));
+	  else
+	    {
+	      _M_owns = _M_device->try_lock_for(__rtime);
+	      return _M_owns;
+	    }
+	 }
+
+      void
+      unlock()
+      {
+	if (!_M_owns)
+	  __throw_system_error(int(errc::operation_not_permitted));
+	else if (_M_device)
+	  {
+	    _M_device->unlock();
+	    _M_owns = false;
+	  }
+      }
+
+      void
+      swap(unique_lock& __u) noexcept
+      {
+	std::swap(_M_device, __u._M_device);
+	std::swap(_M_owns, __u._M_owns);
+      }
+
+      mutex_type*
+      release() noexcept
+      {
+	mutex_type* __ret = _M_device;
+	_M_device = 0;
+	_M_owns = false;
+	return __ret;
+      }
+
+      bool
+      owns_lock() const noexcept
+      { return _M_owns; }
+
+      explicit operator bool() const noexcept
+      { return owns_lock(); }
+
+      mutex_type*
+      mutex() const noexcept
+      { return _M_device; }
+
+    private:
+      mutex_type*	_M_device;
+      bool		_M_owns;
+    };
+
+  /// Swap overload for unique_lock objects.
+  /// @relates unique_lock
+  template<typename _Mutex>
+    inline void
+    swap(unique_lock<_Mutex>& __x, unique_lock<_Mutex>& __y) noexcept
+    { __x.swap(__y); }
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif // C++11
+#endif // _GLIBCXX_UNIQUE_LOCK_H
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@unique_ptr.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@unique_ptr.h
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@unique_ptr.h
@@ -0,0 +1,1165 @@
+// unique_ptr implementation -*- C++ -*-
+
+// Copyright (C) 2008-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/unique_ptr.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{memory}
+ */
+
+#ifndef _UNIQUE_PTR_H
+#define _UNIQUE_PTR_H 1
+
+#include <bits/c++config.h>
+#include <debug/assertions.h>
+#include <type_traits>
+#include <tuple>
+#include <bits/stl_function.h>
+#include <bits/functional_hash.h>
+#if __cplusplus > 201703L
+# include <compare>
+# include <ostream>
+#endif
+
+#if __cplusplus > 202002L && __cpp_constexpr_dynamic_alloc
+# if __cpp_lib_constexpr_memory < 202202L
+// Defined with older value in bits/ptr_traits.h for C++20
+#  undef __cpp_lib_constexpr_memory
+#  define __cpp_lib_constexpr_memory 202202L
+# endif
+#endif
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /**
+   * @addtogroup pointer_abstractions
+   * @{
+   */
+
+#if _GLIBCXX_USE_DEPRECATED
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+  template<typename> class auto_ptr;
+#pragma GCC diagnostic pop
+#endif
+
+  /// Primary template of default_delete, used by unique_ptr for single objects
+  /// @since C++11
+  template<typename _Tp>
+    struct default_delete
+    {
+      /// Default constructor
+      constexpr default_delete() noexcept = default;
+
+      /** @brief Converting constructor.
+       *
+       * Allows conversion from a deleter for objects of another type, `_Up`,
+       * only if `_Up*` is convertible to `_Tp*`.
+       */
+      template<typename _Up,
+	       typename = _Require<is_convertible<_Up*, _Tp*>>>
+	_GLIBCXX23_CONSTEXPR
+        default_delete(const default_delete<_Up>&) noexcept { }
+
+      /// Calls `delete __ptr`
+      _GLIBCXX23_CONSTEXPR
+      void
+      operator()(_Tp* __ptr) const
+      {
+	static_assert(!is_void<_Tp>::value,
+		      "can't delete pointer to incomplete type");
+	static_assert(sizeof(_Tp)>0,
+		      "can't delete pointer to incomplete type");
+	delete __ptr;
+      }
+    };
+
+  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+  // DR 740 - omit specialization for array objects with a compile time length
+
+  /// Specialization of default_delete for arrays, used by `unique_ptr<T[]>`
+  template<typename _Tp>
+    struct default_delete<_Tp[]>
+    {
+    public:
+      /// Default constructor
+      constexpr default_delete() noexcept = default;
+
+      /** @brief Converting constructor.
+       *
+       * Allows conversion from a deleter for arrays of another type, such as
+       * a const-qualified version of `_Tp`.
+       *
+       * Conversions from types derived from `_Tp` are not allowed because
+       * it is undefined to `delete[]` an array of derived types through a
+       * pointer to the base type.
+       */
+      template<typename _Up,
+	       typename = _Require<is_convertible<_Up(*)[], _Tp(*)[]>>>
+	_GLIBCXX23_CONSTEXPR
+        default_delete(const default_delete<_Up[]>&) noexcept { }
+
+      /// Calls `delete[] __ptr`
+      template<typename _Up>
+	_GLIBCXX23_CONSTEXPR
+	typename enable_if<is_convertible<_Up(*)[], _Tp(*)[]>::value>::type
+	operator()(_Up* __ptr) const
+	{
+	  static_assert(sizeof(_Tp)>0,
+			"can't delete pointer to incomplete type");
+	  delete [] __ptr;
+	}
+    };
+
+  /// @cond undocumented
+
+  // Manages the pointer and deleter of a unique_ptr
+  template <typename _Tp, typename _Dp>
+    class __uniq_ptr_impl
+    {
+      template <typename _Up, typename _Ep, typename = void>
+	struct _Ptr
+	{
+	  using type = _Up*;
+	};
+
+      template <typename _Up, typename _Ep>
+	struct
+	_Ptr<_Up, _Ep, __void_t<typename remove_reference<_Ep>::type::pointer>>
+	{
+	  using type = typename remove_reference<_Ep>::type::pointer;
+	};
+
+    public:
+      using _DeleterConstraint = enable_if<
+        __and_<__not_<is_pointer<_Dp>>,
+	       is_default_constructible<_Dp>>::value>;
+
+      using pointer = typename _Ptr<_Tp, _Dp>::type;
+
+      static_assert( !is_rvalue_reference<_Dp>::value,
+		     "unique_ptr's deleter type must be a function object type"
+		     " or an lvalue reference type" );
+
+      __uniq_ptr_impl() = default;
+      _GLIBCXX23_CONSTEXPR
+      __uniq_ptr_impl(pointer __p) : _M_t() { _M_ptr() = __p; }
+
+      template<typename _Del>
+	_GLIBCXX23_CONSTEXPR
+	__uniq_ptr_impl(pointer __p, _Del&& __d)
+	: _M_t(__p, std::forward<_Del>(__d)) { }
+
+      _GLIBCXX23_CONSTEXPR
+      __uniq_ptr_impl(__uniq_ptr_impl&& __u) noexcept
+      : _M_t(std::move(__u._M_t))
+      { __u._M_ptr() = nullptr; }
+
+      _GLIBCXX23_CONSTEXPR
+      __uniq_ptr_impl& operator=(__uniq_ptr_impl&& __u) noexcept
+      {
+	reset(__u.release());
+	_M_deleter() = std::forward<_Dp>(__u._M_deleter());
+	return *this;
+      }
+
+      _GLIBCXX23_CONSTEXPR
+      pointer&   _M_ptr() noexcept { return std::get<0>(_M_t); }
+      _GLIBCXX23_CONSTEXPR
+      pointer    _M_ptr() const noexcept { return std::get<0>(_M_t); }
+      _GLIBCXX23_CONSTEXPR
+      _Dp&       _M_deleter() noexcept { return std::get<1>(_M_t); }
+      _GLIBCXX23_CONSTEXPR
+      const _Dp& _M_deleter() const noexcept { return std::get<1>(_M_t); }
+
+      _GLIBCXX23_CONSTEXPR
+      void reset(pointer __p) noexcept
+      {
+	const pointer __old_p = _M_ptr();
+	_M_ptr() = __p;
+	if (__old_p)
+	  _M_deleter()(__old_p);
+      }
+
+      _GLIBCXX23_CONSTEXPR
+      pointer release() noexcept
+      {
+	pointer __p = _M_ptr();
+	_M_ptr() = nullptr;
+	return __p;
+      }
+
+      _GLIBCXX23_CONSTEXPR
+      void
+      swap(__uniq_ptr_impl& __rhs) noexcept
+      {
+	using std::swap;
+	swap(this->_M_ptr(), __rhs._M_ptr());
+	swap(this->_M_deleter(), __rhs._M_deleter());
+      }
+
+    private:
+      tuple<pointer, _Dp> _M_t;
+    };
+
+  // Defines move construction + assignment as either defaulted or deleted.
+  template <typename _Tp, typename _Dp,
+	    bool = is_move_constructible<_Dp>::value,
+	    bool = is_move_assignable<_Dp>::value>
+    struct __uniq_ptr_data : __uniq_ptr_impl<_Tp, _Dp>
+    {
+      using __uniq_ptr_impl<_Tp, _Dp>::__uniq_ptr_impl;
+      __uniq_ptr_data(__uniq_ptr_data&&) = default;
+      __uniq_ptr_data& operator=(__uniq_ptr_data&&) = default;
+    };
+
+  template <typename _Tp, typename _Dp>
+    struct __uniq_ptr_data<_Tp, _Dp, true, false> : __uniq_ptr_impl<_Tp, _Dp>
+    {
+      using __uniq_ptr_impl<_Tp, _Dp>::__uniq_ptr_impl;
+      __uniq_ptr_data(__uniq_ptr_data&&) = default;
+      __uniq_ptr_data& operator=(__uniq_ptr_data&&) = delete;
+    };
+
+  template <typename _Tp, typename _Dp>
+    struct __uniq_ptr_data<_Tp, _Dp, false, true> : __uniq_ptr_impl<_Tp, _Dp>
+    {
+      using __uniq_ptr_impl<_Tp, _Dp>::__uniq_ptr_impl;
+      __uniq_ptr_data(__uniq_ptr_data&&) = delete;
+      __uniq_ptr_data& operator=(__uniq_ptr_data&&) = default;
+    };
+
+  template <typename _Tp, typename _Dp>
+    struct __uniq_ptr_data<_Tp, _Dp, false, false> : __uniq_ptr_impl<_Tp, _Dp>
+    {
+      using __uniq_ptr_impl<_Tp, _Dp>::__uniq_ptr_impl;
+      __uniq_ptr_data(__uniq_ptr_data&&) = delete;
+      __uniq_ptr_data& operator=(__uniq_ptr_data&&) = delete;
+    };
+  /// @endcond
+
+  // 20.7.1.2 unique_ptr for single objects.
+
+  /// A move-only smart pointer that manages unique ownership of a resource.
+  /// @headerfile memory
+  /// @since C++11
+  template <typename _Tp, typename _Dp = default_delete<_Tp>>
+    class unique_ptr
+    {
+      template <typename _Up>
+	using _DeleterConstraint =
+	  typename __uniq_ptr_impl<_Tp, _Up>::_DeleterConstraint::type;
+
+      __uniq_ptr_data<_Tp, _Dp> _M_t;
+
+    public:
+      using pointer	  = typename __uniq_ptr_impl<_Tp, _Dp>::pointer;
+      using element_type  = _Tp;
+      using deleter_type  = _Dp;
+
+    private:
+      // helper template for detecting a safe conversion from another
+      // unique_ptr
+      template<typename _Up, typename _Ep>
+	using __safe_conversion_up = __and_<
+	  is_convertible<typename unique_ptr<_Up, _Ep>::pointer, pointer>,
+	  __not_<is_array<_Up>>
+        >;
+
+    public:
+      // Constructors.
+
+      /// Default constructor, creates a unique_ptr that owns nothing.
+      template<typename _Del = _Dp, typename = _DeleterConstraint<_Del>>
+	constexpr unique_ptr() noexcept
+	: _M_t()
+	{ }
+
+      /** Takes ownership of a pointer.
+       *
+       * @param __p  A pointer to an object of @c element_type
+       *
+       * The deleter will be value-initialized.
+       */
+      template<typename _Del = _Dp, typename = _DeleterConstraint<_Del>>
+	_GLIBCXX23_CONSTEXPR
+	explicit
+	unique_ptr(pointer __p) noexcept
+	: _M_t(__p)
+        { }
+
+      /** Takes ownership of a pointer.
+       *
+       * @param __p  A pointer to an object of @c element_type
+       * @param __d  A reference to a deleter.
+       *
+       * The deleter will be initialized with @p __d
+       */
+      template<typename _Del = deleter_type,
+	       typename = _Require<is_copy_constructible<_Del>>>
+	_GLIBCXX23_CONSTEXPR
+	unique_ptr(pointer __p, const deleter_type& __d) noexcept
+	: _M_t(__p, __d) { }
+
+      /** Takes ownership of a pointer.
+       *
+       * @param __p  A pointer to an object of @c element_type
+       * @param __d  An rvalue reference to a (non-reference) deleter.
+       *
+       * The deleter will be initialized with @p std::move(__d)
+       */
+      template<typename _Del = deleter_type,
+	       typename = _Require<is_move_constructible<_Del>>>
+	_GLIBCXX23_CONSTEXPR
+	unique_ptr(pointer __p,
+		   __enable_if_t<!is_lvalue_reference<_Del>::value,
+				 _Del&&> __d) noexcept
+	: _M_t(__p, std::move(__d))
+	{ }
+
+      template<typename _Del = deleter_type,
+	       typename _DelUnref = typename remove_reference<_Del>::type>
+	_GLIBCXX23_CONSTEXPR
+	unique_ptr(pointer,
+		   __enable_if_t<is_lvalue_reference<_Del>::value,
+				 _DelUnref&&>) = delete;
+
+      /// Creates a unique_ptr that owns nothing.
+      template<typename _Del = _Dp, typename = _DeleterConstraint<_Del>>
+	constexpr unique_ptr(nullptr_t) noexcept
+	: _M_t()
+	{ }
+
+      // Move constructors.
+
+      /// Move constructor.
+      unique_ptr(unique_ptr&&) = default;
+
+      /** @brief Converting constructor from another type
+       *
+       * Requires that the pointer owned by @p __u is convertible to the
+       * type of pointer owned by this object, @p __u does not own an array,
+       * and @p __u has a compatible deleter type.
+       */
+      template<typename _Up, typename _Ep, typename = _Require<
+               __safe_conversion_up<_Up, _Ep>,
+	       __conditional_t<is_reference<_Dp>::value,
+			       is_same<_Ep, _Dp>,
+			       is_convertible<_Ep, _Dp>>>>
+	_GLIBCXX23_CONSTEXPR
+	unique_ptr(unique_ptr<_Up, _Ep>&& __u) noexcept
+	: _M_t(__u.release(), std::forward<_Ep>(__u.get_deleter()))
+	{ }
+
+#if _GLIBCXX_USE_DEPRECATED
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+      /// Converting constructor from @c auto_ptr
+      template<typename _Up, typename = _Require<
+	       is_convertible<_Up*, _Tp*>, is_same<_Dp, default_delete<_Tp>>>>
+	unique_ptr(auto_ptr<_Up>&& __u) noexcept;
+#pragma GCC diagnostic pop
+#endif
+
+      /// Destructor, invokes the deleter if the stored pointer is not null.
+#if __cplusplus > 202002L && __cpp_constexpr_dynamic_alloc
+      constexpr
+#endif
+      ~unique_ptr() noexcept
+      {
+	static_assert(__is_invocable<deleter_type&, pointer>::value,
+		      "unique_ptr's deleter must be invocable with a pointer");
+	auto& __ptr = _M_t._M_ptr();
+	if (__ptr != nullptr)
+	  get_deleter()(std::move(__ptr));
+	__ptr = pointer();
+      }
+
+      // Assignment.
+
+      /** @brief Move assignment operator.
+       *
+       * Invokes the deleter if this object owns a pointer.
+       */
+      unique_ptr& operator=(unique_ptr&&) = default;
+
+      /** @brief Assignment from another type.
+       *
+       * @param __u  The object to transfer ownership from, which owns a
+       *             convertible pointer to a non-array object.
+       *
+       * Invokes the deleter if this object owns a pointer.
+       */
+      template<typename _Up, typename _Ep>
+	_GLIBCXX23_CONSTEXPR
+        typename enable_if< __and_<
+          __safe_conversion_up<_Up, _Ep>,
+          is_assignable<deleter_type&, _Ep&&>
+          >::value,
+          unique_ptr&>::type
+	operator=(unique_ptr<_Up, _Ep>&& __u) noexcept
+	{
+	  reset(__u.release());
+	  get_deleter() = std::forward<_Ep>(__u.get_deleter());
+	  return *this;
+	}
+
+      /// Reset the %unique_ptr to empty, invoking the deleter if necessary.
+      _GLIBCXX23_CONSTEXPR
+      unique_ptr&
+      operator=(nullptr_t) noexcept
+      {
+	reset();
+	return *this;
+      }
+
+      // Observers.
+
+      /// Dereference the stored pointer.
+      _GLIBCXX23_CONSTEXPR
+      typename add_lvalue_reference<element_type>::type
+      operator*() const noexcept(noexcept(*std::declval<pointer>()))
+      {
+	__glibcxx_assert(get() != pointer());
+	return *get();
+      }
+
+      /// Return the stored pointer.
+      _GLIBCXX23_CONSTEXPR
+      pointer
+      operator->() const noexcept
+      {
+	_GLIBCXX_DEBUG_PEDASSERT(get() != pointer());
+	return get();
+      }
+
+      /// Return the stored pointer.
+      _GLIBCXX23_CONSTEXPR
+      pointer
+      get() const noexcept
+      { return _M_t._M_ptr(); }
+
+      /// Return a reference to the stored deleter.
+      _GLIBCXX23_CONSTEXPR
+      deleter_type&
+      get_deleter() noexcept
+      { return _M_t._M_deleter(); }
+
+      /// Return a reference to the stored deleter.
+      _GLIBCXX23_CONSTEXPR
+      const deleter_type&
+      get_deleter() const noexcept
+      { return _M_t._M_deleter(); }
+
+      /// Return @c true if the stored pointer is not null.
+      _GLIBCXX23_CONSTEXPR
+      explicit operator bool() const noexcept
+      { return get() == pointer() ? false : true; }
+
+      // Modifiers.
+
+      /// Release ownership of any stored pointer.
+      _GLIBCXX23_CONSTEXPR
+      pointer
+      release() noexcept
+      { return _M_t.release(); }
+
+      /** @brief Replace the stored pointer.
+       *
+       * @param __p  The new pointer to store.
+       *
+       * The deleter will be invoked if a pointer is already owned.
+       */
+      _GLIBCXX23_CONSTEXPR
+      void
+      reset(pointer __p = pointer()) noexcept
+      {
+	static_assert(__is_invocable<deleter_type&, pointer>::value,
+		      "unique_ptr's deleter must be invocable with a pointer");
+	_M_t.reset(std::move(__p));
+      }
+
+      /// Exchange the pointer and deleter with another object.
+      _GLIBCXX23_CONSTEXPR
+      void
+      swap(unique_ptr& __u) noexcept
+      {
+	static_assert(__is_swappable<_Dp>::value, "deleter must be swappable");
+	_M_t.swap(__u._M_t);
+      }
+
+      // Disable copy from lvalue.
+      unique_ptr(const unique_ptr&) = delete;
+      unique_ptr& operator=(const unique_ptr&) = delete;
+  };
+
+  // 20.7.1.3 unique_ptr for array objects with a runtime length
+  // [unique.ptr.runtime]
+  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+  // DR 740 - omit specialization for array objects with a compile time length
+
+  /// A move-only smart pointer that manages unique ownership of an array.
+  /// @headerfile memory
+  /// @since C++11
+  template<typename _Tp, typename _Dp>
+    class unique_ptr<_Tp[], _Dp>
+    {
+      template <typename _Up>
+      using _DeleterConstraint =
+	typename __uniq_ptr_impl<_Tp, _Up>::_DeleterConstraint::type;
+
+      __uniq_ptr_data<_Tp, _Dp> _M_t;
+
+      template<typename _Up>
+	using __remove_cv = typename remove_cv<_Up>::type;
+
+      // like is_base_of<_Tp, _Up> but false if unqualified types are the same
+      template<typename _Up>
+	using __is_derived_Tp
+	  = __and_< is_base_of<_Tp, _Up>,
+		    __not_<is_same<__remove_cv<_Tp>, __remove_cv<_Up>>> >;
+
+    public:
+      using pointer	  = typename __uniq_ptr_impl<_Tp, _Dp>::pointer;
+      using element_type  = _Tp;
+      using deleter_type  = _Dp;
+
+      // helper template for detecting a safe conversion from another
+      // unique_ptr
+      template<typename _Up, typename _Ep,
+               typename _UPtr = unique_ptr<_Up, _Ep>,
+	       typename _UP_pointer = typename _UPtr::pointer,
+	       typename _UP_element_type = typename _UPtr::element_type>
+	using __safe_conversion_up = __and_<
+          is_array<_Up>,
+          is_same<pointer, element_type*>,
+          is_same<_UP_pointer, _UP_element_type*>,
+          is_convertible<_UP_element_type(*)[], element_type(*)[]>
+        >;
+
+      // helper template for detecting a safe conversion from a raw pointer
+      template<typename _Up>
+        using __safe_conversion_raw = __and_<
+          __or_<__or_<is_same<_Up, pointer>,
+                      is_same<_Up, nullptr_t>>,
+                __and_<is_pointer<_Up>,
+                       is_same<pointer, element_type*>,
+                       is_convertible<
+                         typename remove_pointer<_Up>::type(*)[],
+                         element_type(*)[]>
+                >
+          >
+        >;
+
+      // Constructors.
+
+      /// Default constructor, creates a unique_ptr that owns nothing.
+      template<typename _Del = _Dp, typename = _DeleterConstraint<_Del>>
+	constexpr unique_ptr() noexcept
+	: _M_t()
+	{ }
+
+      /** Takes ownership of a pointer.
+       *
+       * @param __p  A pointer to an array of a type safely convertible
+       * to an array of @c element_type
+       *
+       * The deleter will be value-initialized.
+       */
+      template<typename _Up,
+	       typename _Vp = _Dp,
+	       typename = _DeleterConstraint<_Vp>,
+	       typename = typename enable_if<
+                 __safe_conversion_raw<_Up>::value, bool>::type>
+	_GLIBCXX23_CONSTEXPR
+	explicit
+	unique_ptr(_Up __p) noexcept
+	: _M_t(__p)
+        { }
+
+      /** Takes ownership of a pointer.
+       *
+       * @param __p  A pointer to an array of a type safely convertible
+       * to an array of @c element_type
+       * @param __d  A reference to a deleter.
+       *
+       * The deleter will be initialized with @p __d
+       */
+      template<typename _Up, typename _Del = deleter_type,
+	       typename = _Require<__safe_conversion_raw<_Up>,
+				   is_copy_constructible<_Del>>>
+	_GLIBCXX23_CONSTEXPR
+	unique_ptr(_Up __p, const deleter_type& __d) noexcept
+	: _M_t(__p, __d) { }
+
+      /** Takes ownership of a pointer.
+       *
+       * @param __p  A pointer to an array of a type safely convertible
+       * to an array of @c element_type
+       * @param __d  A reference to a deleter.
+       *
+       * The deleter will be initialized with @p std::move(__d)
+       */
+      template<typename _Up, typename _Del = deleter_type,
+	       typename = _Require<__safe_conversion_raw<_Up>,
+				   is_move_constructible<_Del>>>
+	_GLIBCXX23_CONSTEXPR
+	unique_ptr(_Up __p,
+		   __enable_if_t<!is_lvalue_reference<_Del>::value,
+				 _Del&&> __d) noexcept
+	: _M_t(std::move(__p), std::move(__d))
+	{ }
+
+      template<typename _Up, typename _Del = deleter_type,
+	       typename _DelUnref = typename remove_reference<_Del>::type,
+	       typename = _Require<__safe_conversion_raw<_Up>>>
+	unique_ptr(_Up,
+		   __enable_if_t<is_lvalue_reference<_Del>::value,
+				 _DelUnref&&>) = delete;
+
+      /// Move constructor.
+      unique_ptr(unique_ptr&&) = default;
+
+      /// Creates a unique_ptr that owns nothing.
+      template<typename _Del = _Dp, typename = _DeleterConstraint<_Del>>
+	constexpr unique_ptr(nullptr_t) noexcept
+	: _M_t()
+        { }
+
+      template<typename _Up, typename _Ep, typename = _Require<
+	       __safe_conversion_up<_Up, _Ep>,
+	       __conditional_t<is_reference<_Dp>::value,
+			       is_same<_Ep, _Dp>,
+			       is_convertible<_Ep, _Dp>>>>
+	_GLIBCXX23_CONSTEXPR
+	unique_ptr(unique_ptr<_Up, _Ep>&& __u) noexcept
+	: _M_t(__u.release(), std::forward<_Ep>(__u.get_deleter()))
+	{ }
+
+      /// Destructor, invokes the deleter if the stored pointer is not null.
+#if __cplusplus > 202002L && __cpp_constexpr_dynamic_alloc
+      constexpr
+#endif
+      ~unique_ptr()
+      {
+	auto& __ptr = _M_t._M_ptr();
+	if (__ptr != nullptr)
+	  get_deleter()(__ptr);
+	__ptr = pointer();
+      }
+
+      // Assignment.
+
+      /** @brief Move assignment operator.
+       *
+       * Invokes the deleter if this object owns a pointer.
+       */
+      unique_ptr&
+      operator=(unique_ptr&&) = default;
+
+      /** @brief Assignment from another type.
+       *
+       * @param __u  The object to transfer ownership from, which owns a
+       *             convertible pointer to an array object.
+       *
+       * Invokes the deleter if this object owns a pointer.
+       */
+      template<typename _Up, typename _Ep>
+	_GLIBCXX23_CONSTEXPR
+	typename
+	enable_if<__and_<__safe_conversion_up<_Up, _Ep>,
+                         is_assignable<deleter_type&, _Ep&&>
+                  >::value,
+                  unique_ptr&>::type
+	operator=(unique_ptr<_Up, _Ep>&& __u) noexcept
+	{
+	  reset(__u.release());
+	  get_deleter() = std::forward<_Ep>(__u.get_deleter());
+	  return *this;
+	}
+
+      /// Reset the %unique_ptr to empty, invoking the deleter if necessary.
+      _GLIBCXX23_CONSTEXPR
+      unique_ptr&
+      operator=(nullptr_t) noexcept
+      {
+	reset();
+	return *this;
+      }
+
+      // Observers.
+
+      /// Access an element of owned array.
+      _GLIBCXX23_CONSTEXPR
+      typename std::add_lvalue_reference<element_type>::type
+      operator[](size_t __i) const
+      {
+	__glibcxx_assert(get() != pointer());
+	return get()[__i];
+      }
+
+      /// Return the stored pointer.
+      _GLIBCXX23_CONSTEXPR
+      pointer
+      get() const noexcept
+      { return _M_t._M_ptr(); }
+
+      /// Return a reference to the stored deleter.
+      _GLIBCXX23_CONSTEXPR
+      deleter_type&
+      get_deleter() noexcept
+      { return _M_t._M_deleter(); }
+
+      /// Return a reference to the stored deleter.
+      _GLIBCXX23_CONSTEXPR
+      const deleter_type&
+      get_deleter() const noexcept
+      { return _M_t._M_deleter(); }
+
+      /// Return @c true if the stored pointer is not null.
+      _GLIBCXX23_CONSTEXPR
+      explicit operator bool() const noexcept
+      { return get() == pointer() ? false : true; }
+
+      // Modifiers.
+
+      /// Release ownership of any stored pointer.
+      _GLIBCXX23_CONSTEXPR
+      pointer
+      release() noexcept
+      { return _M_t.release(); }
+
+      /** @brief Replace the stored pointer.
+       *
+       * @param __p  The new pointer to store.
+       *
+       * The deleter will be invoked if a pointer is already owned.
+       */
+      template <typename _Up,
+                typename = _Require<
+                  __or_<is_same<_Up, pointer>,
+                        __and_<is_same<pointer, element_type*>,
+                               is_pointer<_Up>,
+                               is_convertible<
+                                 typename remove_pointer<_Up>::type(*)[],
+                                 element_type(*)[]
+                               >
+                        >
+                  >
+               >>
+      _GLIBCXX23_CONSTEXPR
+      void
+      reset(_Up __p) noexcept
+      { _M_t.reset(std::move(__p)); }
+
+      _GLIBCXX23_CONSTEXPR
+      void reset(nullptr_t = nullptr) noexcept
+      { reset(pointer()); }
+
+      /// Exchange the pointer and deleter with another object.
+      _GLIBCXX23_CONSTEXPR
+      void
+      swap(unique_ptr& __u) noexcept
+      {
+	static_assert(__is_swappable<_Dp>::value, "deleter must be swappable");
+	_M_t.swap(__u._M_t);
+      }
+
+      // Disable copy from lvalue.
+      unique_ptr(const unique_ptr&) = delete;
+      unique_ptr& operator=(const unique_ptr&) = delete;
+    };
+
+  /// @{
+  /// @relates unique_ptr
+
+  /// Swap overload for unique_ptr
+  template<typename _Tp, typename _Dp>
+    inline
+#if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11
+    // Constrained free swap overload, see p0185r1
+    _GLIBCXX23_CONSTEXPR
+    typename enable_if<__is_swappable<_Dp>::value>::type
+#else
+    void
+#endif
+    swap(unique_ptr<_Tp, _Dp>& __x,
+	 unique_ptr<_Tp, _Dp>& __y) noexcept
+    { __x.swap(__y); }
+
+#if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11
+  template<typename _Tp, typename _Dp>
+    typename enable_if<!__is_swappable<_Dp>::value>::type
+    swap(unique_ptr<_Tp, _Dp>&,
+	 unique_ptr<_Tp, _Dp>&) = delete;
+#endif
+
+  /// Equality operator for unique_ptr objects, compares the owned pointers
+  template<typename _Tp, typename _Dp,
+	   typename _Up, typename _Ep>
+    _GLIBCXX_NODISCARD _GLIBCXX23_CONSTEXPR
+    inline bool
+    operator==(const unique_ptr<_Tp, _Dp>& __x,
+	       const unique_ptr<_Up, _Ep>& __y)
+    { return __x.get() == __y.get(); }
+
+  /// unique_ptr comparison with nullptr
+  template<typename _Tp, typename _Dp>
+    _GLIBCXX_NODISCARD _GLIBCXX23_CONSTEXPR
+    inline bool
+    operator==(const unique_ptr<_Tp, _Dp>& __x, nullptr_t) noexcept
+    { return !__x; }
+
+#ifndef __cpp_lib_three_way_comparison
+  /// unique_ptr comparison with nullptr
+  template<typename _Tp, typename _Dp>
+    _GLIBCXX_NODISCARD
+    inline bool
+    operator==(nullptr_t, const unique_ptr<_Tp, _Dp>& __x) noexcept
+    { return !__x; }
+
+  /// Inequality operator for unique_ptr objects, compares the owned pointers
+  template<typename _Tp, typename _Dp,
+	   typename _Up, typename _Ep>
+    _GLIBCXX_NODISCARD
+    inline bool
+    operator!=(const unique_ptr<_Tp, _Dp>& __x,
+	       const unique_ptr<_Up, _Ep>& __y)
+    { return __x.get() != __y.get(); }
+
+  /// unique_ptr comparison with nullptr
+  template<typename _Tp, typename _Dp>
+    _GLIBCXX_NODISCARD
+    inline bool
+    operator!=(const unique_ptr<_Tp, _Dp>& __x, nullptr_t) noexcept
+    { return (bool)__x; }
+
+  /// unique_ptr comparison with nullptr
+  template<typename _Tp, typename _Dp>
+    _GLIBCXX_NODISCARD
+    inline bool
+    operator!=(nullptr_t, const unique_ptr<_Tp, _Dp>& __x) noexcept
+    { return (bool)__x; }
+#endif // three way comparison
+
+  /// Relational operator for unique_ptr objects, compares the owned pointers
+  template<typename _Tp, typename _Dp,
+	   typename _Up, typename _Ep>
+    _GLIBCXX_NODISCARD _GLIBCXX23_CONSTEXPR
+    inline bool
+    operator<(const unique_ptr<_Tp, _Dp>& __x,
+	      const unique_ptr<_Up, _Ep>& __y)
+    {
+      typedef typename
+	std::common_type<typename unique_ptr<_Tp, _Dp>::pointer,
+	                 typename unique_ptr<_Up, _Ep>::pointer>::type _CT;
+      return std::less<_CT>()(__x.get(), __y.get());
+    }
+
+  /// unique_ptr comparison with nullptr
+  template<typename _Tp, typename _Dp>
+    _GLIBCXX_NODISCARD _GLIBCXX23_CONSTEXPR
+    inline bool
+    operator<(const unique_ptr<_Tp, _Dp>& __x, nullptr_t)
+    {
+      return std::less<typename unique_ptr<_Tp, _Dp>::pointer>()(__x.get(),
+								 nullptr);
+    }
+
+  /// unique_ptr comparison with nullptr
+  template<typename _Tp, typename _Dp>
+    _GLIBCXX_NODISCARD _GLIBCXX23_CONSTEXPR
+    inline bool
+    operator<(nullptr_t, const unique_ptr<_Tp, _Dp>& __x)
+    {
+      return std::less<typename unique_ptr<_Tp, _Dp>::pointer>()(nullptr,
+								 __x.get());
+    }
+
+  /// Relational operator for unique_ptr objects, compares the owned pointers
+  template<typename _Tp, typename _Dp,
+	   typename _Up, typename _Ep>
+    _GLIBCXX_NODISCARD _GLIBCXX23_CONSTEXPR
+    inline bool
+    operator<=(const unique_ptr<_Tp, _Dp>& __x,
+	       const unique_ptr<_Up, _Ep>& __y)
+    { return !(__y < __x); }
+
+  /// unique_ptr comparison with nullptr
+  template<typename _Tp, typename _Dp>
+    _GLIBCXX_NODISCARD _GLIBCXX23_CONSTEXPR
+    inline bool
+    operator<=(const unique_ptr<_Tp, _Dp>& __x, nullptr_t)
+    { return !(nullptr < __x); }
+
+  /// unique_ptr comparison with nullptr
+  template<typename _Tp, typename _Dp>
+    _GLIBCXX_NODISCARD _GLIBCXX23_CONSTEXPR
+    inline bool
+    operator<=(nullptr_t, const unique_ptr<_Tp, _Dp>& __x)
+    { return !(__x < nullptr); }
+
+  /// Relational operator for unique_ptr objects, compares the owned pointers
+  template<typename _Tp, typename _Dp,
+	   typename _Up, typename _Ep>
+    _GLIBCXX_NODISCARD _GLIBCXX23_CONSTEXPR
+    inline bool
+    operator>(const unique_ptr<_Tp, _Dp>& __x,
+	      const unique_ptr<_Up, _Ep>& __y)
+    { return (__y < __x); }
+
+  /// unique_ptr comparison with nullptr
+  template<typename _Tp, typename _Dp>
+    _GLIBCXX_NODISCARD _GLIBCXX23_CONSTEXPR
+    inline bool
+    operator>(const unique_ptr<_Tp, _Dp>& __x, nullptr_t)
+    {
+      return std::less<typename unique_ptr<_Tp, _Dp>::pointer>()(nullptr,
+								 __x.get());
+    }
+
+  /// unique_ptr comparison with nullptr
+  template<typename _Tp, typename _Dp>
+    _GLIBCXX_NODISCARD _GLIBCXX23_CONSTEXPR
+    inline bool
+    operator>(nullptr_t, const unique_ptr<_Tp, _Dp>& __x)
+    {
+      return std::less<typename unique_ptr<_Tp, _Dp>::pointer>()(__x.get(),
+								 nullptr);
+    }
+
+  /// Relational operator for unique_ptr objects, compares the owned pointers
+  template<typename _Tp, typename _Dp,
+	   typename _Up, typename _Ep>
+    _GLIBCXX_NODISCARD _GLIBCXX23_CONSTEXPR
+    inline bool
+    operator>=(const unique_ptr<_Tp, _Dp>& __x,
+	       const unique_ptr<_Up, _Ep>& __y)
+    { return !(__x < __y); }
+
+  /// unique_ptr comparison with nullptr
+  template<typename _Tp, typename _Dp>
+    _GLIBCXX_NODISCARD _GLIBCXX23_CONSTEXPR
+    inline bool
+    operator>=(const unique_ptr<_Tp, _Dp>& __x, nullptr_t)
+    { return !(__x < nullptr); }
+
+  /// unique_ptr comparison with nullptr
+  template<typename _Tp, typename _Dp>
+    _GLIBCXX_NODISCARD inline bool
+    operator>=(nullptr_t, const unique_ptr<_Tp, _Dp>& __x)
+    { return !(nullptr < __x); }
+
+#ifdef __cpp_lib_three_way_comparison
+  template<typename _Tp, typename _Dp, typename _Up, typename _Ep>
+    requires three_way_comparable_with<typename unique_ptr<_Tp, _Dp>::pointer,
+				       typename unique_ptr<_Up, _Ep>::pointer>
+    _GLIBCXX23_CONSTEXPR
+    inline
+    compare_three_way_result_t<typename unique_ptr<_Tp, _Dp>::pointer,
+			       typename unique_ptr<_Up, _Ep>::pointer>
+    operator<=>(const unique_ptr<_Tp, _Dp>& __x,
+		const unique_ptr<_Up, _Ep>& __y)
+    { return compare_three_way()(__x.get(), __y.get()); }
+
+  template<typename _Tp, typename _Dp>
+    requires three_way_comparable<typename unique_ptr<_Tp, _Dp>::pointer>
+    _GLIBCXX23_CONSTEXPR
+    inline
+    compare_three_way_result_t<typename unique_ptr<_Tp, _Dp>::pointer>
+    operator<=>(const unique_ptr<_Tp, _Dp>& __x, nullptr_t)
+    {
+      using pointer = typename unique_ptr<_Tp, _Dp>::pointer;
+      return compare_three_way()(__x.get(), static_cast<pointer>(nullptr));
+    }
+#endif
+  /// @} relates unique_ptr
+
+  /// @cond undocumented
+  template<typename _Up, typename _Ptr = typename _Up::pointer,
+	   bool = __poison_hash<_Ptr>::__enable_hash_call>
+    struct __uniq_ptr_hash
+#if ! _GLIBCXX_INLINE_VERSION
+    : private __poison_hash<_Ptr>
+#endif
+    {
+      size_t
+      operator()(const _Up& __u) const
+      noexcept(noexcept(std::declval<hash<_Ptr>>()(std::declval<_Ptr>())))
+      { return hash<_Ptr>()(__u.get()); }
+    };
+
+  template<typename _Up, typename _Ptr>
+    struct __uniq_ptr_hash<_Up, _Ptr, false>
+    : private __poison_hash<_Ptr>
+    { };
+  /// @endcond
+
+  /// std::hash specialization for unique_ptr.
+  template<typename _Tp, typename _Dp>
+    struct hash<unique_ptr<_Tp, _Dp>>
+    : public __hash_base<size_t, unique_ptr<_Tp, _Dp>>,
+      public __uniq_ptr_hash<unique_ptr<_Tp, _Dp>>
+    { };
+
+#if __cplusplus >= 201402L
+#define __cpp_lib_make_unique 201304L
+
+  /// @cond undocumented
+namespace __detail
+{
+  template<typename _Tp>
+    struct _MakeUniq
+    { typedef unique_ptr<_Tp> __single_object; };
+
+  template<typename _Tp>
+    struct _MakeUniq<_Tp[]>
+    { typedef unique_ptr<_Tp[]> __array; };
+
+  template<typename _Tp, size_t _Bound>
+    struct _MakeUniq<_Tp[_Bound]>
+    { struct __invalid_type { }; };
+
+  template<typename _Tp>
+    using __unique_ptr_t = typename _MakeUniq<_Tp>::__single_object;
+  template<typename _Tp>
+    using __unique_ptr_array_t = typename _MakeUniq<_Tp>::__array;
+  template<typename _Tp>
+    using __invalid_make_unique_t = typename _MakeUniq<_Tp>::__invalid_type;
+}
+  /// @endcond
+
+  /** Create an object owned by a `unique_ptr`.
+   *  @tparam _Tp A non-array object type.
+   *  @param __args Constructor arguments for the new object.
+   *  @returns A `unique_ptr<_Tp>` that owns the new object.
+   *  @since C++14
+   *  @relates unique_ptr
+   */
+  template<typename _Tp, typename... _Args>
+    _GLIBCXX23_CONSTEXPR
+    inline __detail::__unique_ptr_t<_Tp>
+    make_unique(_Args&&... __args)
+    { return unique_ptr<_Tp>(new _Tp(std::forward<_Args>(__args)...)); }
+
+  /** Create an array owned by a `unique_ptr`.
+   *  @tparam _Tp An array type of unknown bound, such as `U[]`.
+   *  @param __num The number of elements of type `U` in the new array.
+   *  @returns A `unique_ptr<U[]>` that owns the new array.
+   *  @since C++14
+   *  @relates unique_ptr
+   *
+   *  The array elements are value-initialized.
+   */
+  template<typename _Tp>
+    _GLIBCXX23_CONSTEXPR
+    inline __detail::__unique_ptr_array_t<_Tp>
+    make_unique(size_t __num)
+    { return unique_ptr<_Tp>(new remove_extent_t<_Tp>[__num]()); }
+
+  /** Disable std::make_unique for arrays of known bound.
+   *  @tparam _Tp An array type of known bound, such as `U[N]`.
+   *  @since C++14
+   *  @relates unique_ptr
+   */
+  template<typename _Tp, typename... _Args>
+    __detail::__invalid_make_unique_t<_Tp>
+    make_unique(_Args&&...) = delete;
+
+#if __cplusplus > 201703L
+  /** Create a default-initialied object owned by a `unique_ptr`.
+   *  @tparam _Tp A non-array object type.
+   *  @returns A `unique_ptr<_Tp>` that owns the new object.
+   *  @since C++20
+   *  @relates unique_ptr
+   */
+  template<typename _Tp>
+    _GLIBCXX23_CONSTEXPR
+    inline __detail::__unique_ptr_t<_Tp>
+    make_unique_for_overwrite()
+    { return unique_ptr<_Tp>(new _Tp); }
+
+  /** Create a default-initialized array owned by a `unique_ptr`.
+   *  @tparam _Tp An array type of unknown bound, such as `U[]`.
+   *  @param __num The number of elements of type `U` in the new array.
+   *  @returns A `unique_ptr<U[]>` that owns the new array.
+   *  @since C++20
+   *  @relates unique_ptr
+   */
+  template<typename _Tp>
+    _GLIBCXX23_CONSTEXPR
+    inline __detail::__unique_ptr_array_t<_Tp>
+    make_unique_for_overwrite(size_t __num)
+    { return unique_ptr<_Tp>(new remove_extent_t<_Tp>[__num]); }
+
+  /** Disable std::make_unique_for_overwrite for arrays of known bound.
+   *  @tparam _Tp An array type of known bound, such as `U[N]`.
+   *  @since C++20
+   *  @relates unique_ptr
+   */
+  template<typename _Tp, typename... _Args>
+    __detail::__invalid_make_unique_t<_Tp>
+    make_unique_for_overwrite(_Args&&...) = delete;
+#endif // C++20
+
+#endif // C++14
+
+#if __cplusplus > 201703L && __cpp_concepts
+  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+  // 2948. unique_ptr does not define operator<< for stream output
+  /// Stream output operator for unique_ptr
+  /// @relates unique_ptr
+  /// @since C++20
+  template<typename _CharT, typename _Traits, typename _Tp, typename _Dp>
+    inline basic_ostream<_CharT, _Traits>&
+    operator<<(basic_ostream<_CharT, _Traits>& __os,
+	       const unique_ptr<_Tp, _Dp>& __p)
+    requires requires { __os << __p.get(); }
+    {
+      __os << __p.get();
+      return __os;
+    }
+#endif // C++20
+
+  /// @} group pointer_abstractions
+
+#if __cplusplus >= 201703L
+  namespace __detail::__variant
+  {
+    template<typename> struct _Never_valueless_alt; // see <variant>
+
+    // Provide the strong exception-safety guarantee when emplacing a
+    // unique_ptr into a variant.
+    template<typename _Tp, typename _Del>
+      struct _Never_valueless_alt<std::unique_ptr<_Tp, _Del>>
+      : std::true_type
+      { };
+  }  // namespace __detail::__variant
+#endif // C++17
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif /* _UNIQUE_PTR_H */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@unique_ptr.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@unique_ptr.h.blob
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@unordered_map.h
@@ -0,0 +1,2215 @@
+// unordered_map implementation -*- C++ -*-
+
+// Copyright (C) 2010-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/unordered_map.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{unordered_map}
+ */
+
+#ifndef _UNORDERED_MAP_H
+#define _UNORDERED_MAP_H
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+_GLIBCXX_BEGIN_NAMESPACE_CONTAINER
+
+  /// Base types for unordered_map.
+  template<bool _Cache>
+    using __umap_traits = __detail::_Hashtable_traits<_Cache, false, true>;
+
+  template<typename _Key,
+	   typename _Tp,
+	   typename _Hash = hash<_Key>,
+	   typename _Pred = std::equal_to<_Key>,
+	   typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >,
+	   typename _Tr = __umap_traits<__cache_default<_Key, _Hash>::value>>
+    using __umap_hashtable = _Hashtable<_Key, std::pair<const _Key, _Tp>,
+                                        _Alloc, __detail::_Select1st,
+				        _Pred, _Hash,
+				        __detail::_Mod_range_hashing,
+				        __detail::_Default_ranged_hash,
+				        __detail::_Prime_rehash_policy, _Tr>;
+
+  /// Base types for unordered_multimap.
+  template<bool _Cache>
+    using __ummap_traits = __detail::_Hashtable_traits<_Cache, false, false>;
+
+  template<typename _Key,
+	   typename _Tp,
+	   typename _Hash = hash<_Key>,
+	   typename _Pred = std::equal_to<_Key>,
+	   typename _Alloc = std::allocator<std::pair<const _Key, _Tp> >,
+	   typename _Tr = __ummap_traits<__cache_default<_Key, _Hash>::value>>
+    using __ummap_hashtable = _Hashtable<_Key, std::pair<const _Key, _Tp>,
+					 _Alloc, __detail::_Select1st,
+					 _Pred, _Hash,
+					 __detail::_Mod_range_hashing,
+					 __detail::_Default_ranged_hash,
+					 __detail::_Prime_rehash_policy, _Tr>;
+
+  template<class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+    class unordered_multimap;
+
+  /**
+   *  @brief A standard container composed of unique keys (containing
+   *  at most one of each key value) that associates values of another type
+   *  with the keys.
+   *
+   *  @ingroup unordered_associative_containers
+   *
+   *  @tparam  _Key    Type of key objects.
+   *  @tparam  _Tp     Type of mapped objects.
+   *  @tparam  _Hash   Hashing function object type, defaults to hash<_Value>.
+   *  @tparam  _Pred   Predicate function object type, defaults
+   *                   to equal_to<_Value>.
+   *  @tparam  _Alloc  Allocator type, defaults to 
+   *                   std::allocator<std::pair<const _Key, _Tp>>.
+   *
+   *  Meets the requirements of a <a href="tables.html#65">container</a>, and
+   *  <a href="tables.html#xx">unordered associative container</a>
+   *
+   * The resulting value type of the container is std::pair<const _Key, _Tp>.
+   *
+   *  Base is _Hashtable, dispatched at compile time via template
+   *  alias __umap_hashtable.
+   */
+  template<typename _Key, typename _Tp,
+	   typename _Hash = hash<_Key>,
+	   typename _Pred = equal_to<_Key>,
+	   typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
+    class unordered_map
+    {
+      typedef __umap_hashtable<_Key, _Tp, _Hash, _Pred, _Alloc>  _Hashtable;
+      _Hashtable _M_h;
+
+    public:
+      // typedefs:
+      ///@{
+      /// Public typedefs.
+      typedef typename _Hashtable::key_type	key_type;
+      typedef typename _Hashtable::value_type	value_type;
+      typedef typename _Hashtable::mapped_type	mapped_type;
+      typedef typename _Hashtable::hasher	hasher;
+      typedef typename _Hashtable::key_equal	key_equal;
+      typedef typename _Hashtable::allocator_type allocator_type;
+      ///@}
+
+      ///@{
+      ///  Iterator-related typedefs.
+      typedef typename _Hashtable::pointer		pointer;
+      typedef typename _Hashtable::const_pointer	const_pointer;
+      typedef typename _Hashtable::reference		reference;
+      typedef typename _Hashtable::const_reference	const_reference;
+      typedef typename _Hashtable::iterator		iterator;
+      typedef typename _Hashtable::const_iterator	const_iterator;
+      typedef typename _Hashtable::local_iterator	local_iterator;
+      typedef typename _Hashtable::const_local_iterator	const_local_iterator;
+      typedef typename _Hashtable::size_type		size_type;
+      typedef typename _Hashtable::difference_type	difference_type;
+      ///@}
+
+#if __cplusplus > 201402L
+      using node_type = typename _Hashtable::node_type;
+      using insert_return_type = typename _Hashtable::insert_return_type;
+#endif
+
+      //construct/destroy/copy
+
+      /// Default constructor.
+      unordered_map() = default;
+
+      /**
+       *  @brief  Default constructor creates no elements.
+       *  @param __n  Minimal initial number of buckets.
+       *  @param __hf  A hash functor.
+       *  @param __eql  A key equality functor.
+       *  @param __a  An allocator object.
+       */
+      explicit
+      unordered_map(size_type __n,
+		    const hasher& __hf = hasher(),
+		    const key_equal& __eql = key_equal(),
+		    const allocator_type& __a = allocator_type())
+      : _M_h(__n, __hf, __eql, __a)
+      { }
+
+      /**
+       *  @brief  Builds an %unordered_map from a range.
+       *  @param  __first  An input iterator.
+       *  @param  __last  An input iterator.
+       *  @param __n  Minimal initial number of buckets.
+       *  @param __hf  A hash functor.
+       *  @param __eql  A key equality functor.
+       *  @param __a  An allocator object.
+       *
+       *  Create an %unordered_map consisting of copies of the elements from
+       *  [__first,__last).  This is linear in N (where N is
+       *  distance(__first,__last)).
+       */
+      template<typename _InputIterator>
+	unordered_map(_InputIterator __first, _InputIterator __last,
+		      size_type __n = 0,
+		      const hasher& __hf = hasher(),
+		      const key_equal& __eql = key_equal(),
+		      const allocator_type& __a = allocator_type())
+	: _M_h(__first, __last, __n, __hf, __eql, __a)
+	{ }
+
+      /// Copy constructor.
+      unordered_map(const unordered_map&) = default;
+
+      /// Move constructor.
+      unordered_map(unordered_map&&) = default;
+
+      /**
+       *  @brief Creates an %unordered_map with no elements.
+       *  @param __a An allocator object.
+       */
+      explicit
+      unordered_map(const allocator_type& __a)
+	: _M_h(__a)
+      { }
+
+      /*
+       *  @brief Copy constructor with allocator argument.
+       * @param  __uset  Input %unordered_map to copy.
+       * @param  __a  An allocator object.
+       */
+      unordered_map(const unordered_map& __umap,
+		    const allocator_type& __a)
+      : _M_h(__umap._M_h, __a)
+      { }
+
+      /*
+       *  @brief  Move constructor with allocator argument.
+       *  @param  __uset Input %unordered_map to move.
+       *  @param  __a    An allocator object.
+       */
+      unordered_map(unordered_map&& __umap,
+		    const allocator_type& __a)
+	noexcept( noexcept(_Hashtable(std::move(__umap._M_h), __a)) )
+      : _M_h(std::move(__umap._M_h), __a)
+      { }
+
+      /**
+       *  @brief  Builds an %unordered_map from an initializer_list.
+       *  @param  __l  An initializer_list.
+       *  @param __n  Minimal initial number of buckets.
+       *  @param __hf  A hash functor.
+       *  @param __eql  A key equality functor.
+       *  @param  __a  An allocator object.
+       *
+       *  Create an %unordered_map consisting of copies of the elements in the
+       *  list. This is linear in N (where N is @a __l.size()).
+       */
+      unordered_map(initializer_list<value_type> __l,
+		    size_type __n = 0,
+		    const hasher& __hf = hasher(),
+		    const key_equal& __eql = key_equal(),
+		    const allocator_type& __a = allocator_type())
+      : _M_h(__l, __n, __hf, __eql, __a)
+      { }
+
+      unordered_map(size_type __n, const allocator_type& __a)
+      : unordered_map(__n, hasher(), key_equal(), __a)
+      { }
+
+      unordered_map(size_type __n, const hasher& __hf,
+		    const allocator_type& __a)
+      : unordered_map(__n, __hf, key_equal(), __a)
+      { }
+
+      template<typename _InputIterator>
+	unordered_map(_InputIterator __first, _InputIterator __last,
+		      size_type __n,
+		      const allocator_type& __a)
+	: unordered_map(__first, __last, __n, hasher(), key_equal(), __a)
+	{ }
+
+      template<typename _InputIterator>
+	unordered_map(_InputIterator __first, _InputIterator __last,
+		      size_type __n, const hasher& __hf,
+		      const allocator_type& __a)
+	  : unordered_map(__first, __last, __n, __hf, key_equal(), __a)
+	{ }
+
+      unordered_map(initializer_list<value_type> __l,
+		    size_type __n,
+		    const allocator_type& __a)
+      : unordered_map(__l, __n, hasher(), key_equal(), __a)
+      { }
+
+      unordered_map(initializer_list<value_type> __l,
+		    size_type __n, const hasher& __hf,
+		    const allocator_type& __a)
+      : unordered_map(__l, __n, __hf, key_equal(), __a)
+      { }
+
+      /// Copy assignment operator.
+      unordered_map&
+      operator=(const unordered_map&) = default;
+
+      /// Move assignment operator.
+      unordered_map&
+      operator=(unordered_map&&) = default;
+
+      /**
+       *  @brief  %Unordered_map list assignment operator.
+       *  @param  __l  An initializer_list.
+       *
+       *  This function fills an %unordered_map with copies of the elements in
+       *  the initializer list @a __l.
+       *
+       *  Note that the assignment completely changes the %unordered_map and
+       *  that the resulting %unordered_map's size is the same as the number
+       *  of elements assigned.
+       */
+      unordered_map&
+      operator=(initializer_list<value_type> __l)
+      {
+	_M_h = __l;
+	return *this;
+      }
+
+      ///  Returns the allocator object used by the %unordered_map.
+      allocator_type
+      get_allocator() const noexcept
+      { return _M_h.get_allocator(); }
+
+      // size and capacity:
+
+      ///  Returns true if the %unordered_map is empty.
+      _GLIBCXX_NODISCARD bool
+      empty() const noexcept
+      { return _M_h.empty(); }
+
+      ///  Returns the size of the %unordered_map.
+      size_type
+      size() const noexcept
+      { return _M_h.size(); }
+
+      ///  Returns the maximum size of the %unordered_map.
+      size_type
+      max_size() const noexcept
+      { return _M_h.max_size(); }
+
+      // iterators.
+
+      /**
+       *  Returns a read/write iterator that points to the first element in the
+       *  %unordered_map.
+       */
+      iterator
+      begin() noexcept
+      { return _M_h.begin(); }
+
+      ///@{
+      /**
+       *  Returns a read-only (constant) iterator that points to the first
+       *  element in the %unordered_map.
+       */
+      const_iterator
+      begin() const noexcept
+      { return _M_h.begin(); }
+
+      const_iterator
+      cbegin() const noexcept
+      { return _M_h.begin(); }
+      ///@}
+
+      /**
+       *  Returns a read/write iterator that points one past the last element in
+       *  the %unordered_map.
+       */
+      iterator
+      end() noexcept
+      { return _M_h.end(); }
+
+      ///@{
+      /**
+       *  Returns a read-only (constant) iterator that points one past the last
+       *  element in the %unordered_map.
+       */
+      const_iterator
+      end() const noexcept
+      { return _M_h.end(); }
+
+      const_iterator
+      cend() const noexcept
+      { return _M_h.end(); }
+      ///@}
+
+      // modifiers.
+
+      /**
+       *  @brief Attempts to build and insert a std::pair into the
+       *  %unordered_map.
+       *
+       *  @param __args  Arguments used to generate a new pair instance (see
+       *	        std::piecewise_contruct for passing arguments to each
+       *	        part of the pair constructor).
+       *
+       *  @return  A pair, of which the first element is an iterator that points
+       *           to the possibly inserted pair, and the second is a bool that
+       *           is true if the pair was actually inserted.
+       *
+       *  This function attempts to build and insert a (key, value) %pair into
+       *  the %unordered_map.
+       *  An %unordered_map relies on unique keys and thus a %pair is only
+       *  inserted if its first element (the key) is not already present in the
+       *  %unordered_map.
+       *
+       *  Insertion requires amortized constant time.
+       */
+      template<typename... _Args>
+	std::pair<iterator, bool>
+	emplace(_Args&&... __args)
+	{ return _M_h.emplace(std::forward<_Args>(__args)...); }
+
+      /**
+       *  @brief Attempts to build and insert a std::pair into the
+       *  %unordered_map.
+       *
+       *  @param  __pos  An iterator that serves as a hint as to where the pair
+       *                should be inserted.
+       *  @param  __args  Arguments used to generate a new pair instance (see
+       *	         std::piecewise_contruct for passing arguments to each
+       *	         part of the pair constructor).
+       *  @return An iterator that points to the element with key of the
+       *          std::pair built from @a __args (may or may not be that
+       *          std::pair).
+       *
+       *  This function is not concerned about whether the insertion took place,
+       *  and thus does not return a boolean like the single-argument emplace()
+       *  does.
+       *  Note that the first parameter is only a hint and can potentially
+       *  improve the performance of the insertion process. A bad hint would
+       *  cause no gains in efficiency.
+       *
+       *  See
+       *  https://gcc.gnu.org/onlinedocs/libstdc++/manual/associative.html#containers.associative.insert_hints
+       *  for more on @a hinting.
+       *
+       *  Insertion requires amortized constant time.
+       */
+      template<typename... _Args>
+	iterator
+	emplace_hint(const_iterator __pos, _Args&&... __args)
+	{ return _M_h.emplace_hint(__pos, std::forward<_Args>(__args)...); }
+
+#if __cplusplus > 201402L
+      /// Extract a node.
+      node_type
+      extract(const_iterator __pos)
+      {
+	__glibcxx_assert(__pos != end());
+	return _M_h.extract(__pos);
+      }
+
+      /// Extract a node.
+      node_type
+      extract(const key_type& __key)
+      { return _M_h.extract(__key); }
+
+      /// Re-insert an extracted node.
+      insert_return_type
+      insert(node_type&& __nh)
+      { return _M_h._M_reinsert_node(std::move(__nh)); }
+
+      /// Re-insert an extracted node.
+      iterator
+      insert(const_iterator, node_type&& __nh)
+      { return _M_h._M_reinsert_node(std::move(__nh)).position; }
+
+#define __cpp_lib_unordered_map_try_emplace 201411L
+      /**
+       *  @brief Attempts to build and insert a std::pair into the
+       *  %unordered_map.
+       *
+       *  @param __k    Key to use for finding a possibly existing pair in
+       *                the unordered_map.
+       *  @param __args  Arguments used to generate the .second for a 
+       *                new pair instance.
+       *
+       *  @return  A pair, of which the first element is an iterator that points
+       *           to the possibly inserted pair, and the second is a bool that
+       *           is true if the pair was actually inserted.
+       *
+       *  This function attempts to build and insert a (key, value) %pair into
+       *  the %unordered_map.
+       *  An %unordered_map relies on unique keys and thus a %pair is only
+       *  inserted if its first element (the key) is not already present in the
+       *  %unordered_map.
+       *  If a %pair is not inserted, this function has no effect.
+       *
+       *  Insertion requires amortized constant time.
+       */
+      template <typename... _Args>
+	pair<iterator, bool>
+	try_emplace(const key_type& __k, _Args&&... __args)
+	{
+	  return _M_h.try_emplace(cend(), __k, std::forward<_Args>(__args)...);
+	}
+
+      // move-capable overload
+      template <typename... _Args>
+	pair<iterator, bool>
+	try_emplace(key_type&& __k, _Args&&... __args)
+	{
+	  return _M_h.try_emplace(cend(), std::move(__k),
+				  std::forward<_Args>(__args)...);
+	}
+
+      /**
+       *  @brief Attempts to build and insert a std::pair into the
+       *  %unordered_map.
+       *
+       *  @param  __hint  An iterator that serves as a hint as to where the pair
+       *                should be inserted.
+       *  @param __k    Key to use for finding a possibly existing pair in
+       *                the unordered_map.
+       *  @param __args  Arguments used to generate the .second for a 
+       *                new pair instance.
+       *  @return An iterator that points to the element with key of the
+       *          std::pair built from @a __args (may or may not be that
+       *          std::pair).
+       *
+       *  This function is not concerned about whether the insertion took place,
+       *  and thus does not return a boolean like the single-argument emplace()
+       *  does. However, if insertion did not take place,
+       *  this function has no effect.
+       *  Note that the first parameter is only a hint and can potentially
+       *  improve the performance of the insertion process. A bad hint would
+       *  cause no gains in efficiency.
+       *
+       *  See
+       *  https://gcc.gnu.org/onlinedocs/libstdc++/manual/associative.html#containers.associative.insert_hints
+       *  for more on @a hinting.
+       *
+       *  Insertion requires amortized constant time.
+       */
+      template <typename... _Args>
+	iterator
+	try_emplace(const_iterator __hint, const key_type& __k,
+		    _Args&&... __args)
+	{
+	  return _M_h.try_emplace(__hint, __k,
+				  std::forward<_Args>(__args)...).first;
+	}
+
+      // move-capable overload
+      template <typename... _Args>
+	iterator
+	try_emplace(const_iterator __hint, key_type&& __k, _Args&&... __args)
+	{
+	  return _M_h.try_emplace(__hint, std::move(__k),
+				  std::forward<_Args>(__args)...).first;
+	}
+#endif // C++17
+
+      ///@{
+      /**
+       *  @brief Attempts to insert a std::pair into the %unordered_map.
+
+       *  @param __x Pair to be inserted (see std::make_pair for easy
+       *	     creation of pairs).
+       *
+       *  @return  A pair, of which the first element is an iterator that 
+       *           points to the possibly inserted pair, and the second is 
+       *           a bool that is true if the pair was actually inserted.
+       *
+       *  This function attempts to insert a (key, value) %pair into the
+       *  %unordered_map. An %unordered_map relies on unique keys and thus a
+       *  %pair is only inserted if its first element (the key) is not already
+       *  present in the %unordered_map.
+       *
+       *  Insertion requires amortized constant time.
+       */
+      std::pair<iterator, bool>
+      insert(const value_type& __x)
+      { return _M_h.insert(__x); }
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 2354. Unnecessary copying when inserting into maps with braced-init
+      std::pair<iterator, bool>
+      insert(value_type&& __x)
+      { return _M_h.insert(std::move(__x)); }
+
+      template<typename _Pair>
+	__enable_if_t<is_constructible<value_type, _Pair&&>::value,
+		      pair<iterator, bool>>
+	insert(_Pair&& __x)
+        { return _M_h.emplace(std::forward<_Pair>(__x)); }
+      ///@}
+
+      ///@{
+      /**
+       *  @brief Attempts to insert a std::pair into the %unordered_map.
+       *  @param  __hint  An iterator that serves as a hint as to where the
+       *                 pair should be inserted.
+       *  @param  __x  Pair to be inserted (see std::make_pair for easy creation
+       *               of pairs).
+       *  @return An iterator that points to the element with key of
+       *           @a __x (may or may not be the %pair passed in).
+       *
+       *  This function is not concerned about whether the insertion took place,
+       *  and thus does not return a boolean like the single-argument insert()
+       *  does.  Note that the first parameter is only a hint and can
+       *  potentially improve the performance of the insertion process.  A bad
+       *  hint would cause no gains in efficiency.
+       *
+       *  See
+       *  https://gcc.gnu.org/onlinedocs/libstdc++/manual/associative.html#containers.associative.insert_hints
+       *  for more on @a hinting.
+       *
+       *  Insertion requires amortized constant time.
+       */
+      iterator
+      insert(const_iterator __hint, const value_type& __x)
+      { return _M_h.insert(__hint, __x); }
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 2354. Unnecessary copying when inserting into maps with braced-init
+      iterator
+      insert(const_iterator __hint, value_type&& __x)
+      { return _M_h.insert(__hint, std::move(__x)); }
+
+      template<typename _Pair>
+	__enable_if_t<is_constructible<value_type, _Pair&&>::value, iterator>
+	insert(const_iterator __hint, _Pair&& __x)
+	{ return _M_h.emplace_hint(__hint, std::forward<_Pair>(__x)); }
+      ///@}
+
+      /**
+       *  @brief A template function that attempts to insert a range of
+       *  elements.
+       *  @param  __first  Iterator pointing to the start of the range to be
+       *                   inserted.
+       *  @param  __last  Iterator pointing to the end of the range.
+       *
+       *  Complexity similar to that of the range constructor.
+       */
+      template<typename _InputIterator>
+	void
+	insert(_InputIterator __first, _InputIterator __last)
+	{ _M_h.insert(__first, __last); }
+
+      /**
+       *  @brief Attempts to insert a list of elements into the %unordered_map.
+       *  @param  __l  A std::initializer_list<value_type> of elements
+       *               to be inserted.
+       *
+       *  Complexity similar to that of the range constructor.
+       */
+      void
+      insert(initializer_list<value_type> __l)
+      { _M_h.insert(__l); }
+
+
+#if __cplusplus > 201402L
+      /**
+       *  @brief Attempts to insert a std::pair into the %unordered_map.
+       *  @param __k    Key to use for finding a possibly existing pair in
+       *                the map.
+       *  @param __obj  Argument used to generate the .second for a pair 
+       *                instance.
+       *
+       *  @return  A pair, of which the first element is an iterator that 
+       *           points to the possibly inserted pair, and the second is 
+       *           a bool that is true if the pair was actually inserted.
+       *
+       *  This function attempts to insert a (key, value) %pair into the
+       *  %unordered_map. An %unordered_map relies on unique keys and thus a
+       *  %pair is only inserted if its first element (the key) is not already
+       *  present in the %unordered_map.
+       *  If the %pair was already in the %unordered_map, the .second of 
+       *  the %pair is assigned from __obj.
+       *
+       *  Insertion requires amortized constant time.
+       */
+      template <typename _Obj>
+	pair<iterator, bool>
+	insert_or_assign(const key_type& __k, _Obj&& __obj)
+	{
+	  auto __ret = _M_h.try_emplace(cend(), __k,
+					std::forward<_Obj>(__obj));
+	  if (!__ret.second)
+	    __ret.first->second = std::forward<_Obj>(__obj);
+	  return __ret;
+	}
+
+      // move-capable overload
+      template <typename _Obj>
+	pair<iterator, bool>
+	insert_or_assign(key_type&& __k, _Obj&& __obj)
+	{
+	  auto __ret = _M_h.try_emplace(cend(), std::move(__k),
+					std::forward<_Obj>(__obj));
+	  if (!__ret.second)
+	    __ret.first->second = std::forward<_Obj>(__obj);
+	  return __ret;
+	}
+
+      /**
+       *  @brief Attempts to insert a std::pair into the %unordered_map.
+       *  @param  __hint  An iterator that serves as a hint as to where the
+       *                  pair should be inserted.
+       *  @param __k    Key to use for finding a possibly existing pair in
+       *                the unordered_map.
+       *  @param __obj  Argument used to generate the .second for a pair 
+       *                instance.
+       *  @return An iterator that points to the element with key of
+       *           @a __x (may or may not be the %pair passed in).
+       *
+       *  This function is not concerned about whether the insertion took place,
+       *  and thus does not return a boolean like the single-argument insert()
+       *  does.         
+       *  If the %pair was already in the %unordered map, the .second of
+       *  the %pair is assigned from __obj.
+       *  Note that the first parameter is only a hint and can
+       *  potentially improve the performance of the insertion process.  A bad
+       *  hint would cause no gains in efficiency.
+       *
+       *  See
+       *  https://gcc.gnu.org/onlinedocs/libstdc++/manual/associative.html#containers.associative.insert_hints
+       *  for more on @a hinting.
+       *
+       *  Insertion requires amortized constant time.
+       */
+      template <typename _Obj>
+	iterator
+	insert_or_assign(const_iterator __hint, const key_type& __k,
+			 _Obj&& __obj)
+	{
+	  auto __ret = _M_h.try_emplace(__hint, __k, std::forward<_Obj>(__obj));
+	  if (!__ret.second)
+	    __ret.first->second = std::forward<_Obj>(__obj);
+	  return __ret.first;
+	}
+
+      // move-capable overload
+      template <typename _Obj>
+	iterator
+	insert_or_assign(const_iterator __hint, key_type&& __k, _Obj&& __obj)
+	{
+	  auto __ret = _M_h.try_emplace(__hint, std::move(__k),
+					std::forward<_Obj>(__obj));
+	  if (!__ret.second)
+	    __ret.first->second = std::forward<_Obj>(__obj);
+	  return __ret.first;
+	}
+#endif
+
+      ///@{
+      /**
+       *  @brief Erases an element from an %unordered_map.
+       *  @param  __position  An iterator pointing to the element to be erased.
+       *  @return An iterator pointing to the element immediately following
+       *          @a __position prior to the element being erased. If no such
+       *          element exists, end() is returned.
+       *
+       *  This function erases an element, pointed to by the given iterator,
+       *  from an %unordered_map.
+       *  Note that this function only erases the element, and that if the
+       *  element is itself a pointer, the pointed-to memory is not touched in
+       *  any way.  Managing the pointer is the user's responsibility.
+       */
+      iterator
+      erase(const_iterator __position)
+      { return _M_h.erase(__position); }
+
+      // LWG 2059.
+      iterator
+      erase(iterator __position)
+      { return _M_h.erase(__position); }
+      ///@}
+
+      /**
+       *  @brief Erases elements according to the provided key.
+       *  @param  __x  Key of element to be erased.
+       *  @return  The number of elements erased.
+       *
+       *  This function erases all the elements located by the given key from
+       *  an %unordered_map. For an %unordered_map the result of this function
+       *  can only be 0 (not present) or 1 (present).
+       *  Note that this function only erases the element, and that if the
+       *  element is itself a pointer, the pointed-to memory is not touched in
+       *  any way.  Managing the pointer is the user's responsibility.
+       */
+      size_type
+      erase(const key_type& __x)
+      { return _M_h.erase(__x); }
+
+      /**
+       *  @brief Erases a [__first,__last) range of elements from an
+       *  %unordered_map.
+       *  @param  __first  Iterator pointing to the start of the range to be
+       *                  erased.
+       *  @param __last  Iterator pointing to the end of the range to
+       *                be erased.
+       *  @return The iterator @a __last.
+       *
+       *  This function erases a sequence of elements from an %unordered_map.
+       *  Note that this function only erases the elements, and that if
+       *  the element is itself a pointer, the pointed-to memory is not touched
+       *  in any way.  Managing the pointer is the user's responsibility.
+       */
+      iterator
+      erase(const_iterator __first, const_iterator __last)
+      { return _M_h.erase(__first, __last); }
+
+      /**
+       *  Erases all elements in an %unordered_map.
+       *  Note that this function only erases the elements, and that if the
+       *  elements themselves are pointers, the pointed-to memory is not touched
+       *  in any way.  Managing the pointer is the user's responsibility.
+       */
+      void
+      clear() noexcept
+      { _M_h.clear(); }
+
+      /**
+       *  @brief  Swaps data with another %unordered_map.
+       *  @param  __x  An %unordered_map of the same element and allocator
+       *  types.
+       *
+       *  This exchanges the elements between two %unordered_map in constant
+       *  time.
+       *  Note that the global std::swap() function is specialized such that
+       *  std::swap(m1,m2) will feed to this function.
+       */
+      void
+      swap(unordered_map& __x)
+      noexcept( noexcept(_M_h.swap(__x._M_h)) )
+      { _M_h.swap(__x._M_h); }
+
+#if __cplusplus > 201402L
+      template<typename, typename, typename>
+	friend class std::_Hash_merge_helper;
+
+      template<typename _H2, typename _P2>
+	void
+	merge(unordered_map<_Key, _Tp, _H2, _P2, _Alloc>& __source)
+	{
+	  using _Merge_helper = _Hash_merge_helper<unordered_map, _H2, _P2>;
+	  _M_h._M_merge_unique(_Merge_helper::_S_get_table(__source));
+	}
+
+      template<typename _H2, typename _P2>
+	void
+	merge(unordered_map<_Key, _Tp, _H2, _P2, _Alloc>&& __source)
+	{ merge(__source); }
+
+      template<typename _H2, typename _P2>
+	void
+	merge(unordered_multimap<_Key, _Tp, _H2, _P2, _Alloc>& __source)
+	{
+	  using _Merge_helper = _Hash_merge_helper<unordered_map, _H2, _P2>;
+	  _M_h._M_merge_unique(_Merge_helper::_S_get_table(__source));
+	}
+
+      template<typename _H2, typename _P2>
+	void
+	merge(unordered_multimap<_Key, _Tp, _H2, _P2, _Alloc>&& __source)
+	{ merge(__source); }
+#endif // C++17
+
+      // observers.
+
+      ///  Returns the hash functor object with which the %unordered_map was
+      ///  constructed.
+      hasher
+      hash_function() const
+      { return _M_h.hash_function(); }
+
+      ///  Returns the key comparison object with which the %unordered_map was
+      ///  constructed.
+      key_equal
+      key_eq() const
+      { return _M_h.key_eq(); }
+
+      // lookup.
+
+      ///@{
+      /**
+       *  @brief Tries to locate an element in an %unordered_map.
+       *  @param  __x  Key to be located.
+       *  @return  Iterator pointing to sought-after element, or end() if not
+       *           found.
+       *
+       *  This function takes a key and tries to locate the element with which
+       *  the key matches.  If successful the function returns an iterator
+       *  pointing to the sought after element.  If unsuccessful it returns the
+       *  past-the-end ( @c end() ) iterator.
+       */
+      iterator
+      find(const key_type& __x)
+      { return _M_h.find(__x); }
+
+#if __cplusplus > 201703L
+      template<typename _Kt>
+	auto
+	find(const _Kt& __x) -> decltype(_M_h._M_find_tr(__x))
+	{ return _M_h._M_find_tr(__x); }
+#endif
+
+      const_iterator
+      find(const key_type& __x) const
+      { return _M_h.find(__x); }
+
+#if __cplusplus > 201703L
+      template<typename _Kt>
+	auto
+	find(const _Kt& __x) const -> decltype(_M_h._M_find_tr(__x))
+	{ return _M_h._M_find_tr(__x); }
+#endif
+      ///@}
+
+      ///@{
+      /**
+       *  @brief  Finds the number of elements.
+       *  @param  __x  Key to count.
+       *  @return  Number of elements with specified key.
+       *
+       *  This function only makes sense for %unordered_multimap; for
+       *  %unordered_map the result will either be 0 (not present) or 1
+       *  (present).
+       */
+      size_type
+      count(const key_type& __x) const
+      { return _M_h.count(__x); }
+
+#if __cplusplus > 201703L
+      template<typename _Kt>
+	auto
+	count(const _Kt& __x) const -> decltype(_M_h._M_count_tr(__x))
+	{ return _M_h._M_count_tr(__x); }
+#endif
+      ///@}
+
+#if __cplusplus > 201703L
+      ///@{
+      /**
+       *  @brief  Finds whether an element with the given key exists.
+       *  @param  __x  Key of elements to be located.
+       *  @return  True if there is any element with the specified key.
+       */
+      bool
+      contains(const key_type& __x) const
+      { return _M_h.find(__x) != _M_h.end(); }
+
+      template<typename _Kt>
+	auto
+	contains(const _Kt& __x) const
+	-> decltype(_M_h._M_find_tr(__x), void(), true)
+	{ return _M_h._M_find_tr(__x) != _M_h.end(); }
+      ///@}
+#endif
+
+      ///@{
+      /**
+       *  @brief Finds a subsequence matching given key.
+       *  @param  __x  Key to be located.
+       *  @return  Pair of iterators that possibly points to the subsequence
+       *           matching given key.
+       *
+       *  This function probably only makes sense for %unordered_multimap.
+       */
+      std::pair<iterator, iterator>
+      equal_range(const key_type& __x)
+      { return _M_h.equal_range(__x); }
+
+#if __cplusplus > 201703L
+      template<typename _Kt>
+	auto
+	equal_range(const _Kt& __x)
+	-> decltype(_M_h._M_equal_range_tr(__x))
+	{ return _M_h._M_equal_range_tr(__x); }
+#endif
+
+      std::pair<const_iterator, const_iterator>
+      equal_range(const key_type& __x) const
+      { return _M_h.equal_range(__x); }
+
+#if __cplusplus > 201703L
+      template<typename _Kt>
+	auto
+	equal_range(const _Kt& __x) const
+	-> decltype(_M_h._M_equal_range_tr(__x))
+	{ return _M_h._M_equal_range_tr(__x); }
+#endif
+      ///@}
+
+      ///@{
+      /**
+       *  @brief  Subscript ( @c [] ) access to %unordered_map data.
+       *  @param  __k  The key for which data should be retrieved.
+       *  @return  A reference to the data of the (key,data) %pair.
+       *
+       *  Allows for easy lookup with the subscript ( @c [] )operator.  Returns
+       *  data associated with the key specified in subscript.  If the key does
+       *  not exist, a pair with that key is created using default values, which
+       *  is then returned.
+       *
+       *  Lookup requires constant time.
+       */
+      mapped_type&
+      operator[](const key_type& __k)
+      { return _M_h[__k]; }
+
+      mapped_type&
+      operator[](key_type&& __k)
+      { return _M_h[std::move(__k)]; }
+      ///@}
+
+      ///@{
+      /**
+       *  @brief  Access to %unordered_map data.
+       *  @param  __k  The key for which data should be retrieved.
+       *  @return  A reference to the data whose key is equal to @a __k, if
+       *           such a data is present in the %unordered_map.
+       *  @throw  std::out_of_range  If no such data is present.
+       */
+      mapped_type&
+      at(const key_type& __k)
+      { return _M_h.at(__k); }
+
+      const mapped_type&
+      at(const key_type& __k) const
+      { return _M_h.at(__k); }
+      ///@}
+
+      // bucket interface.
+
+      /// Returns the number of buckets of the %unordered_map.
+      size_type
+      bucket_count() const noexcept
+      { return _M_h.bucket_count(); }
+
+      /// Returns the maximum number of buckets of the %unordered_map.
+      size_type
+      max_bucket_count() const noexcept
+      { return _M_h.max_bucket_count(); }
+
+      /*
+       * @brief  Returns the number of elements in a given bucket.
+       * @param  __n  A bucket index.
+       * @return  The number of elements in the bucket.
+       */
+      size_type
+      bucket_size(size_type __n) const
+      { return _M_h.bucket_size(__n); }
+
+      /*
+       * @brief  Returns the bucket index of a given element.
+       * @param  __key  A key instance.
+       * @return  The key bucket index.
+       */
+      size_type
+      bucket(const key_type& __key) const
+      { return _M_h.bucket(__key); }
+      
+      /**
+       *  @brief  Returns a read/write iterator pointing to the first bucket
+       *         element.
+       *  @param  __n The bucket index.
+       *  @return  A read/write local iterator.
+       */
+      local_iterator
+      begin(size_type __n)
+      { return _M_h.begin(__n); }
+
+      ///@{
+      /**
+       *  @brief  Returns a read-only (constant) iterator pointing to the first
+       *         bucket element.
+       *  @param  __n The bucket index.
+       *  @return  A read-only local iterator.
+       */
+      const_local_iterator
+      begin(size_type __n) const
+      { return _M_h.begin(__n); }
+
+      const_local_iterator
+      cbegin(size_type __n) const
+      { return _M_h.cbegin(__n); }
+      ///@}
+
+      /**
+       *  @brief  Returns a read/write iterator pointing to one past the last
+       *         bucket elements.
+       *  @param  __n The bucket index.
+       *  @return  A read/write local iterator.
+       */
+      local_iterator
+      end(size_type __n)
+      { return _M_h.end(__n); }
+
+      ///@{
+      /**
+       *  @brief  Returns a read-only (constant) iterator pointing to one past
+       *         the last bucket elements.
+       *  @param  __n The bucket index.
+       *  @return  A read-only local iterator.
+       */
+      const_local_iterator
+      end(size_type __n) const
+      { return _M_h.end(__n); }
+
+      const_local_iterator
+      cend(size_type __n) const
+      { return _M_h.cend(__n); }
+      ///@}
+
+      // hash policy.
+
+      /// Returns the average number of elements per bucket.
+      float
+      load_factor() const noexcept
+      { return _M_h.load_factor(); }
+
+      /// Returns a positive number that the %unordered_map tries to keep the
+      /// load factor less than or equal to.
+      float
+      max_load_factor() const noexcept
+      { return _M_h.max_load_factor(); }
+
+      /**
+       *  @brief  Change the %unordered_map maximum load factor.
+       *  @param  __z The new maximum load factor.
+       */
+      void
+      max_load_factor(float __z)
+      { _M_h.max_load_factor(__z); }
+
+      /**
+       *  @brief  May rehash the %unordered_map.
+       *  @param  __n The new number of buckets.
+       *
+       *  Rehash will occur only if the new number of buckets respect the
+       *  %unordered_map maximum load factor.
+       */
+      void
+      rehash(size_type __n)
+      { _M_h.rehash(__n); }
+
+      /**
+       *  @brief  Prepare the %unordered_map for a specified number of
+       *          elements.
+       *  @param  __n Number of elements required.
+       *
+       *  Same as rehash(ceil(n / max_load_factor())).
+       */
+      void
+      reserve(size_type __n)
+      { _M_h.reserve(__n); }
+
+      template<typename _Key1, typename _Tp1, typename _Hash1, typename _Pred1,
+	       typename _Alloc1>
+        friend bool
+	operator==(const unordered_map<_Key1, _Tp1, _Hash1, _Pred1, _Alloc1>&,
+		   const unordered_map<_Key1, _Tp1, _Hash1, _Pred1, _Alloc1>&);
+    };
+
+#if __cpp_deduction_guides >= 201606
+
+  template<typename _InputIterator,
+	   typename _Hash = hash<__iter_key_t<_InputIterator>>,
+	   typename _Pred = equal_to<__iter_key_t<_InputIterator>>,
+	   typename _Allocator = allocator<__iter_to_alloc_t<_InputIterator>>,
+	   typename = _RequireInputIter<_InputIterator>,
+	   typename = _RequireNotAllocatorOrIntegral<_Hash>,
+	   typename = _RequireNotAllocator<_Pred>,
+	   typename = _RequireAllocator<_Allocator>>
+    unordered_map(_InputIterator, _InputIterator,
+		  typename unordered_map<int, int>::size_type = {},
+		  _Hash = _Hash(), _Pred = _Pred(), _Allocator = _Allocator())
+    -> unordered_map<__iter_key_t<_InputIterator>,
+		     __iter_val_t<_InputIterator>,
+		     _Hash, _Pred, _Allocator>;
+
+  template<typename _Key, typename _Tp, typename _Hash = hash<_Key>,
+	   typename _Pred = equal_to<_Key>,
+	   typename _Allocator = allocator<pair<const _Key, _Tp>>,
+	   typename = _RequireNotAllocatorOrIntegral<_Hash>,
+	   typename = _RequireNotAllocator<_Pred>,
+	   typename = _RequireAllocator<_Allocator>>
+    unordered_map(initializer_list<pair<_Key, _Tp>>,
+		  typename unordered_map<int, int>::size_type = {},
+		  _Hash = _Hash(), _Pred = _Pred(), _Allocator = _Allocator())
+    -> unordered_map<_Key, _Tp, _Hash, _Pred, _Allocator>;
+
+  template<typename _InputIterator, typename _Allocator,
+	   typename = _RequireInputIter<_InputIterator>,
+	   typename = _RequireAllocator<_Allocator>>
+    unordered_map(_InputIterator, _InputIterator,
+		  typename unordered_map<int, int>::size_type, _Allocator)
+    -> unordered_map<__iter_key_t<_InputIterator>,
+		     __iter_val_t<_InputIterator>,
+		     hash<__iter_key_t<_InputIterator>>,
+		     equal_to<__iter_key_t<_InputIterator>>,
+		     _Allocator>;
+
+  template<typename _InputIterator, typename _Allocator,
+	   typename = _RequireInputIter<_InputIterator>,
+	   typename = _RequireAllocator<_Allocator>>
+    unordered_map(_InputIterator, _InputIterator, _Allocator)
+    -> unordered_map<__iter_key_t<_InputIterator>,
+		     __iter_val_t<_InputIterator>,
+		     hash<__iter_key_t<_InputIterator>>,
+		     equal_to<__iter_key_t<_InputIterator>>,
+		     _Allocator>;
+
+  template<typename _InputIterator, typename _Hash, typename _Allocator,
+	   typename = _RequireInputIter<_InputIterator>,
+	   typename = _RequireNotAllocatorOrIntegral<_Hash>,
+	   typename = _RequireAllocator<_Allocator>>
+    unordered_map(_InputIterator, _InputIterator,
+		  typename unordered_map<int, int>::size_type,
+		  _Hash, _Allocator)
+    -> unordered_map<__iter_key_t<_InputIterator>,
+		     __iter_val_t<_InputIterator>, _Hash,
+		     equal_to<__iter_key_t<_InputIterator>>, _Allocator>;
+
+  template<typename _Key, typename _Tp, typename _Allocator,
+	   typename = _RequireAllocator<_Allocator>>
+    unordered_map(initializer_list<pair<_Key, _Tp>>,
+		  typename unordered_map<int, int>::size_type,
+		  _Allocator)
+    -> unordered_map<_Key, _Tp, hash<_Key>, equal_to<_Key>, _Allocator>;
+
+  template<typename _Key, typename _Tp, typename _Allocator,
+	   typename = _RequireAllocator<_Allocator>>
+    unordered_map(initializer_list<pair<_Key, _Tp>>, _Allocator)
+    -> unordered_map<_Key, _Tp, hash<_Key>, equal_to<_Key>, _Allocator>;
+
+  template<typename _Key, typename _Tp, typename _Hash, typename _Allocator,
+	   typename = _RequireNotAllocatorOrIntegral<_Hash>,
+	   typename = _RequireAllocator<_Allocator>>
+    unordered_map(initializer_list<pair<_Key, _Tp>>,
+		  typename unordered_map<int, int>::size_type,
+		  _Hash, _Allocator)
+    -> unordered_map<_Key, _Tp, _Hash, equal_to<_Key>, _Allocator>;
+
+#endif
+
+  /**
+   *  @brief A standard container composed of equivalent keys
+   *  (possibly containing multiple of each key value) that associates
+   *  values of another type with the keys.
+   *
+   *  @ingroup unordered_associative_containers
+   *
+   *  @tparam  _Key    Type of key objects.
+   *  @tparam  _Tp     Type of mapped objects.
+   *  @tparam  _Hash   Hashing function object type, defaults to hash<_Value>.
+   *  @tparam  _Pred   Predicate function object type, defaults
+   *                   to equal_to<_Value>.
+   *  @tparam  _Alloc  Allocator type, defaults to
+   *                   std::allocator<std::pair<const _Key, _Tp>>.
+   *
+   *  Meets the requirements of a <a href="tables.html#65">container</a>, and
+   *  <a href="tables.html#xx">unordered associative container</a>
+   *
+   * The resulting value type of the container is std::pair<const _Key, _Tp>.
+   *
+   *  Base is _Hashtable, dispatched at compile time via template
+   *  alias __ummap_hashtable.
+   */
+  template<typename _Key, typename _Tp,
+	   typename _Hash = hash<_Key>,
+	   typename _Pred = equal_to<_Key>,
+	   typename _Alloc = allocator<std::pair<const _Key, _Tp>>>
+    class unordered_multimap
+    {
+      typedef __ummap_hashtable<_Key, _Tp, _Hash, _Pred, _Alloc>  _Hashtable;
+      _Hashtable _M_h;
+
+    public:
+      // typedefs:
+      ///@{
+      /// Public typedefs.
+      typedef typename _Hashtable::key_type	key_type;
+      typedef typename _Hashtable::value_type	value_type;
+      typedef typename _Hashtable::mapped_type	mapped_type;
+      typedef typename _Hashtable::hasher	hasher;
+      typedef typename _Hashtable::key_equal	key_equal;
+      typedef typename _Hashtable::allocator_type allocator_type;
+      ///@}
+
+      ///@{
+      ///  Iterator-related typedefs.
+      typedef typename _Hashtable::pointer		pointer;
+      typedef typename _Hashtable::const_pointer	const_pointer;
+      typedef typename _Hashtable::reference		reference;
+      typedef typename _Hashtable::const_reference	const_reference;
+      typedef typename _Hashtable::iterator		iterator;
+      typedef typename _Hashtable::const_iterator	const_iterator;
+      typedef typename _Hashtable::local_iterator	local_iterator;
+      typedef typename _Hashtable::const_local_iterator	const_local_iterator;
+      typedef typename _Hashtable::size_type		size_type;
+      typedef typename _Hashtable::difference_type	difference_type;
+      ///@}
+
+#if __cplusplus > 201402L
+      using node_type = typename _Hashtable::node_type;
+#endif
+
+      //construct/destroy/copy
+
+      /// Default constructor.
+      unordered_multimap() = default;
+
+      /**
+       *  @brief  Default constructor creates no elements.
+       *  @param __n  Mnimal initial number of buckets.
+       *  @param __hf  A hash functor.
+       *  @param __eql  A key equality functor.
+       *  @param __a  An allocator object.
+       */
+      explicit
+      unordered_multimap(size_type __n,
+			 const hasher& __hf = hasher(),
+			 const key_equal& __eql = key_equal(),
+			 const allocator_type& __a = allocator_type())
+      : _M_h(__n, __hf, __eql, __a)
+      { }
+
+      /**
+       *  @brief  Builds an %unordered_multimap from a range.
+       *  @param  __first An input iterator.
+       *  @param  __last  An input iterator.
+       *  @param __n      Minimal initial number of buckets.
+       *  @param __hf     A hash functor.
+       *  @param __eql    A key equality functor.
+       *  @param __a      An allocator object.
+       *
+       *  Create an %unordered_multimap consisting of copies of the elements
+       *  from [__first,__last).  This is linear in N (where N is
+       *  distance(__first,__last)).
+       */
+      template<typename _InputIterator>
+	unordered_multimap(_InputIterator __first, _InputIterator __last,
+			   size_type __n = 0,
+			   const hasher& __hf = hasher(),
+			   const key_equal& __eql = key_equal(),
+			   const allocator_type& __a = allocator_type())
+	: _M_h(__first, __last, __n, __hf, __eql, __a)
+	{ }
+
+      /// Copy constructor.
+      unordered_multimap(const unordered_multimap&) = default;
+
+      /// Move constructor.
+      unordered_multimap(unordered_multimap&&) = default;
+
+      /**
+       *  @brief Creates an %unordered_multimap with no elements.
+       *  @param __a An allocator object.
+       */
+      explicit
+      unordered_multimap(const allocator_type& __a)
+      : _M_h(__a)
+      { }
+
+      /*
+       *  @brief Copy constructor with allocator argument.
+       * @param  __uset  Input %unordered_multimap to copy.
+       * @param  __a  An allocator object.
+       */
+      unordered_multimap(const unordered_multimap& __ummap,
+			 const allocator_type& __a)
+      : _M_h(__ummap._M_h, __a)
+      { }
+
+      /*
+       *  @brief  Move constructor with allocator argument.
+       *  @param  __uset Input %unordered_multimap to move.
+       *  @param  __a    An allocator object.
+       */
+      unordered_multimap(unordered_multimap&& __ummap,
+			 const allocator_type& __a)
+	noexcept( noexcept(_Hashtable(std::move(__ummap._M_h), __a)) )
+      : _M_h(std::move(__ummap._M_h), __a)
+      { }
+
+      /**
+       *  @brief  Builds an %unordered_multimap from an initializer_list.
+       *  @param  __l  An initializer_list.
+       *  @param __n  Minimal initial number of buckets.
+       *  @param __hf  A hash functor.
+       *  @param __eql  A key equality functor.
+       *  @param  __a  An allocator object.
+       *
+       *  Create an %unordered_multimap consisting of copies of the elements in
+       *  the list. This is linear in N (where N is @a __l.size()).
+       */
+      unordered_multimap(initializer_list<value_type> __l,
+			 size_type __n = 0,
+			 const hasher& __hf = hasher(),
+			 const key_equal& __eql = key_equal(),
+			 const allocator_type& __a = allocator_type())
+      : _M_h(__l, __n, __hf, __eql, __a)
+      { }
+
+      unordered_multimap(size_type __n, const allocator_type& __a)
+      : unordered_multimap(__n, hasher(), key_equal(), __a)
+      { }
+
+      unordered_multimap(size_type __n, const hasher& __hf,
+			 const allocator_type& __a)
+      : unordered_multimap(__n, __hf, key_equal(), __a)
+      { }
+
+      template<typename _InputIterator>
+	unordered_multimap(_InputIterator __first, _InputIterator __last,
+			   size_type __n,
+			   const allocator_type& __a)
+	: unordered_multimap(__first, __last, __n, hasher(), key_equal(), __a)
+	{ }
+
+      template<typename _InputIterator>
+	unordered_multimap(_InputIterator __first, _InputIterator __last,
+			   size_type __n, const hasher& __hf,
+			   const allocator_type& __a)
+	: unordered_multimap(__first, __last, __n, __hf, key_equal(), __a)
+	{ }
+
+      unordered_multimap(initializer_list<value_type> __l,
+			 size_type __n,
+			 const allocator_type& __a)
+      : unordered_multimap(__l, __n, hasher(), key_equal(), __a)
+      { }
+
+      unordered_multimap(initializer_list<value_type> __l,
+			 size_type __n, const hasher& __hf,
+			 const allocator_type& __a)
+      : unordered_multimap(__l, __n, __hf, key_equal(), __a)
+      { }
+
+      /// Copy assignment operator.
+      unordered_multimap&
+      operator=(const unordered_multimap&) = default;
+
+      /// Move assignment operator.
+      unordered_multimap&
+      operator=(unordered_multimap&&) = default;
+
+      /**
+       *  @brief  %Unordered_multimap list assignment operator.
+       *  @param  __l  An initializer_list.
+       *
+       *  This function fills an %unordered_multimap with copies of the
+       *  elements in the initializer list @a __l.
+       *
+       *  Note that the assignment completely changes the %unordered_multimap
+       *  and that the resulting %unordered_multimap's size is the same as the
+       *  number of elements assigned.
+       */
+      unordered_multimap&
+      operator=(initializer_list<value_type> __l)
+      {
+	_M_h = __l;
+	return *this;
+      }
+
+      ///  Returns the allocator object used by the %unordered_multimap.
+      allocator_type
+      get_allocator() const noexcept
+      { return _M_h.get_allocator(); }
+
+      // size and capacity:
+
+      ///  Returns true if the %unordered_multimap is empty.
+      _GLIBCXX_NODISCARD bool
+      empty() const noexcept
+      { return _M_h.empty(); }
+
+      ///  Returns the size of the %unordered_multimap.
+      size_type
+      size() const noexcept
+      { return _M_h.size(); }
+
+      ///  Returns the maximum size of the %unordered_multimap.
+      size_type
+      max_size() const noexcept
+      { return _M_h.max_size(); }
+
+      // iterators.
+
+      /**
+       *  Returns a read/write iterator that points to the first element in the
+       *  %unordered_multimap.
+       */
+      iterator
+      begin() noexcept
+      { return _M_h.begin(); }
+
+      ///@{
+      /**
+       *  Returns a read-only (constant) iterator that points to the first
+       *  element in the %unordered_multimap.
+       */
+      const_iterator
+      begin() const noexcept
+      { return _M_h.begin(); }
+
+      const_iterator
+      cbegin() const noexcept
+      { return _M_h.begin(); }
+      ///@}
+
+      /**
+       *  Returns a read/write iterator that points one past the last element in
+       *  the %unordered_multimap.
+       */
+      iterator
+      end() noexcept
+      { return _M_h.end(); }
+
+      ///@{
+      /**
+       *  Returns a read-only (constant) iterator that points one past the last
+       *  element in the %unordered_multimap.
+       */
+      const_iterator
+      end() const noexcept
+      { return _M_h.end(); }
+
+      const_iterator
+      cend() const noexcept
+      { return _M_h.end(); }
+      ///@}
+
+      // modifiers.
+
+      /**
+       *  @brief Attempts to build and insert a std::pair into the
+       *  %unordered_multimap.
+       *
+       *  @param __args  Arguments used to generate a new pair instance (see
+       *	        std::piecewise_contruct for passing arguments to each
+       *	        part of the pair constructor).
+       *
+       *  @return  An iterator that points to the inserted pair.
+       *
+       *  This function attempts to build and insert a (key, value) %pair into
+       *  the %unordered_multimap.
+       *
+       *  Insertion requires amortized constant time.
+       */
+      template<typename... _Args>
+	iterator
+	emplace(_Args&&... __args)
+	{ return _M_h.emplace(std::forward<_Args>(__args)...); }
+
+      /**
+       *  @brief Attempts to build and insert a std::pair into the
+       *  %unordered_multimap.
+       *
+       *  @param  __pos  An iterator that serves as a hint as to where the pair
+       *                should be inserted.
+       *  @param  __args  Arguments used to generate a new pair instance (see
+       *	         std::piecewise_contruct for passing arguments to each
+       *	         part of the pair constructor).
+       *  @return An iterator that points to the element with key of the
+       *          std::pair built from @a __args.
+       *
+       *  Note that the first parameter is only a hint and can potentially
+       *  improve the performance of the insertion process. A bad hint would
+       *  cause no gains in efficiency.
+       *
+       *  See
+       *  https://gcc.gnu.org/onlinedocs/libstdc++/manual/associative.html#containers.associative.insert_hints
+       *  for more on @a hinting.
+       *
+       *  Insertion requires amortized constant time.
+       */
+      template<typename... _Args>
+	iterator
+	emplace_hint(const_iterator __pos, _Args&&... __args)
+	{ return _M_h.emplace_hint(__pos, std::forward<_Args>(__args)...); }
+
+      ///@{
+      /**
+       *  @brief Inserts a std::pair into the %unordered_multimap.
+       *  @param __x Pair to be inserted (see std::make_pair for easy
+       *	     creation of pairs).
+       *
+       *  @return  An iterator that points to the inserted pair.
+       *
+       *  Insertion requires amortized constant time.
+       */
+      iterator
+      insert(const value_type& __x)
+      { return _M_h.insert(__x); }
+
+      iterator
+      insert(value_type&& __x)
+      { return _M_h.insert(std::move(__x)); }
+
+      template<typename _Pair>
+	__enable_if_t<is_constructible<value_type, _Pair&&>::value, iterator>
+	insert(_Pair&& __x)
+        { return _M_h.emplace(std::forward<_Pair>(__x)); }
+      ///@}
+
+      ///@{
+      /**
+       *  @brief Inserts a std::pair into the %unordered_multimap.
+       *  @param  __hint  An iterator that serves as a hint as to where the
+       *                 pair should be inserted.
+       *  @param  __x  Pair to be inserted (see std::make_pair for easy creation
+       *               of pairs).
+       *  @return An iterator that points to the element with key of
+       *           @a __x (may or may not be the %pair passed in).
+       *
+       *  Note that the first parameter is only a hint and can potentially
+       *  improve the performance of the insertion process.  A bad hint would
+       *  cause no gains in efficiency.
+       *
+       *  See
+       *  https://gcc.gnu.org/onlinedocs/libstdc++/manual/associative.html#containers.associative.insert_hints
+       *  for more on @a hinting.
+       *
+       *  Insertion requires amortized constant time.
+       */
+      iterator
+      insert(const_iterator __hint, const value_type& __x)
+      { return _M_h.insert(__hint, __x); }
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 2354. Unnecessary copying when inserting into maps with braced-init
+      iterator
+      insert(const_iterator __hint, value_type&& __x)
+      { return _M_h.insert(__hint, std::move(__x)); }
+
+      template<typename _Pair>
+	__enable_if_t<is_constructible<value_type, _Pair&&>::value, iterator>
+	insert(const_iterator __hint, _Pair&& __x)
+        { return _M_h.emplace_hint(__hint, std::forward<_Pair>(__x)); }
+      ///@}
+
+      /**
+       *  @brief A template function that attempts to insert a range of
+       *  elements.
+       *  @param  __first  Iterator pointing to the start of the range to be
+       *                   inserted.
+       *  @param  __last  Iterator pointing to the end of the range.
+       *
+       *  Complexity similar to that of the range constructor.
+       */
+      template<typename _InputIterator>
+	void
+	insert(_InputIterator __first, _InputIterator __last)
+	{ _M_h.insert(__first, __last); }
+
+      /**
+       *  @brief Attempts to insert a list of elements into the
+       *  %unordered_multimap.
+       *  @param  __l  A std::initializer_list<value_type> of elements
+       *               to be inserted.
+       *
+       *  Complexity similar to that of the range constructor.
+       */
+      void
+      insert(initializer_list<value_type> __l)
+      { _M_h.insert(__l); }
+
+#if __cplusplus > 201402L
+      /// Extract a node.
+      node_type
+      extract(const_iterator __pos)
+      {
+	__glibcxx_assert(__pos != end());
+	return _M_h.extract(__pos);
+      }
+
+      /// Extract a node.
+      node_type
+      extract(const key_type& __key)
+      { return _M_h.extract(__key); }
+
+      /// Re-insert an extracted node.
+      iterator
+      insert(node_type&& __nh)
+      { return _M_h._M_reinsert_node_multi(cend(), std::move(__nh)); }
+
+      /// Re-insert an extracted node.
+      iterator
+      insert(const_iterator __hint, node_type&& __nh)
+      { return _M_h._M_reinsert_node_multi(__hint, std::move(__nh)); }
+#endif // C++17
+
+      ///@{
+      /**
+       *  @brief Erases an element from an %unordered_multimap.
+       *  @param  __position  An iterator pointing to the element to be erased.
+       *  @return An iterator pointing to the element immediately following
+       *          @a __position prior to the element being erased. If no such
+       *          element exists, end() is returned.
+       *
+       *  This function erases an element, pointed to by the given iterator,
+       *  from an %unordered_multimap.
+       *  Note that this function only erases the element, and that if the
+       *  element is itself a pointer, the pointed-to memory is not touched in
+       *  any way.  Managing the pointer is the user's responsibility.
+       */
+      iterator
+      erase(const_iterator __position)
+      { return _M_h.erase(__position); }
+
+      // LWG 2059.
+      iterator
+      erase(iterator __position)
+      { return _M_h.erase(__position); }
+      ///@}
+
+      /**
+       *  @brief Erases elements according to the provided key.
+       *  @param  __x  Key of elements to be erased.
+       *  @return  The number of elements erased.
+       *
+       *  This function erases all the elements located by the given key from
+       *  an %unordered_multimap.
+       *  Note that this function only erases the element, and that if the
+       *  element is itself a pointer, the pointed-to memory is not touched in
+       *  any way.  Managing the pointer is the user's responsibility.
+       */
+      size_type
+      erase(const key_type& __x)
+      { return _M_h.erase(__x); }
+
+      /**
+       *  @brief Erases a [__first,__last) range of elements from an
+       *  %unordered_multimap.
+       *  @param  __first  Iterator pointing to the start of the range to be
+       *                  erased.
+       *  @param __last  Iterator pointing to the end of the range to
+       *                be erased.
+       *  @return The iterator @a __last.
+       *
+       *  This function erases a sequence of elements from an
+       *  %unordered_multimap.
+       *  Note that this function only erases the elements, and that if
+       *  the element is itself a pointer, the pointed-to memory is not touched
+       *  in any way.  Managing the pointer is the user's responsibility.
+       */
+      iterator
+      erase(const_iterator __first, const_iterator __last)
+      { return _M_h.erase(__first, __last); }
+
+      /**
+       *  Erases all elements in an %unordered_multimap.
+       *  Note that this function only erases the elements, and that if the
+       *  elements themselves are pointers, the pointed-to memory is not touched
+       *  in any way.  Managing the pointer is the user's responsibility.
+       */
+      void
+      clear() noexcept
+      { _M_h.clear(); }
+
+      /**
+       *  @brief  Swaps data with another %unordered_multimap.
+       *  @param  __x  An %unordered_multimap of the same element and allocator
+       *  types.
+       *
+       *  This exchanges the elements between two %unordered_multimap in
+       *  constant time.
+       *  Note that the global std::swap() function is specialized such that
+       *  std::swap(m1,m2) will feed to this function.
+       */
+      void
+      swap(unordered_multimap& __x)
+      noexcept( noexcept(_M_h.swap(__x._M_h)) )
+      { _M_h.swap(__x._M_h); }
+
+#if __cplusplus > 201402L
+      template<typename, typename, typename>
+	friend class std::_Hash_merge_helper;
+
+      template<typename _H2, typename _P2>
+	void
+	merge(unordered_multimap<_Key, _Tp, _H2, _P2, _Alloc>& __source)
+	{
+	  using _Merge_helper
+	    = _Hash_merge_helper<unordered_multimap, _H2, _P2>;
+	  _M_h._M_merge_multi(_Merge_helper::_S_get_table(__source));
+	}
+
+      template<typename _H2, typename _P2>
+	void
+	merge(unordered_multimap<_Key, _Tp, _H2, _P2, _Alloc>&& __source)
+	{ merge(__source); }
+
+      template<typename _H2, typename _P2>
+	void
+	merge(unordered_map<_Key, _Tp, _H2, _P2, _Alloc>& __source)
+	{
+	  using _Merge_helper
+	    = _Hash_merge_helper<unordered_multimap, _H2, _P2>;
+	  _M_h._M_merge_multi(_Merge_helper::_S_get_table(__source));
+	}
+
+      template<typename _H2, typename _P2>
+	void
+	merge(unordered_map<_Key, _Tp, _H2, _P2, _Alloc>&& __source)
+	{ merge(__source); }
+#endif // C++17
+
+      // observers.
+
+      ///  Returns the hash functor object with which the %unordered_multimap
+      ///  was constructed.
+      hasher
+      hash_function() const
+      { return _M_h.hash_function(); }
+
+      ///  Returns the key comparison object with which the %unordered_multimap
+      ///  was constructed.
+      key_equal
+      key_eq() const
+      { return _M_h.key_eq(); }
+
+      // lookup.
+
+      ///@{
+      /**
+       *  @brief Tries to locate an element in an %unordered_multimap.
+       *  @param  __x  Key to be located.
+       *  @return  Iterator pointing to sought-after element, or end() if not
+       *           found.
+       *
+       *  This function takes a key and tries to locate the element with which
+       *  the key matches.  If successful the function returns an iterator
+       *  pointing to the sought after element.  If unsuccessful it returns the
+       *  past-the-end ( @c end() ) iterator.
+       */
+      iterator
+      find(const key_type& __x)
+      { return _M_h.find(__x); }
+
+#if __cplusplus > 201703L
+      template<typename _Kt>
+	auto
+	find(const _Kt& __x) -> decltype(_M_h._M_find_tr(__x))
+	{ return _M_h._M_find_tr(__x); }
+#endif
+
+      const_iterator
+      find(const key_type& __x) const
+      { return _M_h.find(__x); }
+
+#if __cplusplus > 201703L
+      template<typename _Kt>
+	auto
+	find(const _Kt& __x) const -> decltype(_M_h._M_find_tr(__x))
+	{ return _M_h._M_find_tr(__x); }
+#endif
+      ///@}
+
+      ///@{
+      /**
+       *  @brief  Finds the number of elements.
+       *  @param  __x  Key to count.
+       *  @return  Number of elements with specified key.
+       */
+      size_type
+      count(const key_type& __x) const
+      { return _M_h.count(__x); }
+
+#if __cplusplus > 201703L
+      template<typename _Kt>
+	auto
+	count(const _Kt& __x) const -> decltype(_M_h._M_count_tr(__x))
+	{ return _M_h._M_count_tr(__x); }
+#endif
+      ///@}
+
+#if __cplusplus > 201703L
+      ///@{
+      /**
+       *  @brief  Finds whether an element with the given key exists.
+       *  @param  __x  Key of elements to be located.
+       *  @return  True if there is any element with the specified key.
+       */
+      bool
+      contains(const key_type& __x) const
+      { return _M_h.find(__x) != _M_h.end(); }
+
+      template<typename _Kt>
+	auto
+	contains(const _Kt& __x) const
+	-> decltype(_M_h._M_find_tr(__x), void(), true)
+	{ return _M_h._M_find_tr(__x) != _M_h.end(); }
+      ///@}
+#endif
+
+      ///@{
+      /**
+       *  @brief Finds a subsequence matching given key.
+       *  @param  __x  Key to be located.
+       *  @return  Pair of iterators that possibly points to the subsequence
+       *           matching given key.
+       */
+      std::pair<iterator, iterator>
+      equal_range(const key_type& __x)
+      { return _M_h.equal_range(__x); }
+
+#if __cplusplus > 201703L
+      template<typename _Kt>
+	auto
+	equal_range(const _Kt& __x)
+	-> decltype(_M_h._M_equal_range_tr(__x))
+	{ return _M_h._M_equal_range_tr(__x); }
+#endif
+
+      std::pair<const_iterator, const_iterator>
+      equal_range(const key_type& __x) const
+      { return _M_h.equal_range(__x); }
+
+#if __cplusplus > 201703L
+      template<typename _Kt>
+	auto
+	equal_range(const _Kt& __x) const
+	-> decltype(_M_h._M_equal_range_tr(__x))
+	{ return _M_h._M_equal_range_tr(__x); }
+#endif
+      ///@}
+
+      // bucket interface.
+
+      /// Returns the number of buckets of the %unordered_multimap.
+      size_type
+      bucket_count() const noexcept
+      { return _M_h.bucket_count(); }
+
+      /// Returns the maximum number of buckets of the %unordered_multimap.
+      size_type
+      max_bucket_count() const noexcept
+      { return _M_h.max_bucket_count(); }
+
+      /*
+       * @brief  Returns the number of elements in a given bucket.
+       * @param  __n  A bucket index.
+       * @return  The number of elements in the bucket.
+       */
+      size_type
+      bucket_size(size_type __n) const
+      { return _M_h.bucket_size(__n); }
+
+      /*
+       * @brief  Returns the bucket index of a given element.
+       * @param  __key  A key instance.
+       * @return  The key bucket index.
+       */
+      size_type
+      bucket(const key_type& __key) const
+      { return _M_h.bucket(__key); }
+      
+      /**
+       *  @brief  Returns a read/write iterator pointing to the first bucket
+       *         element.
+       *  @param  __n The bucket index.
+       *  @return  A read/write local iterator.
+       */
+      local_iterator
+      begin(size_type __n)
+      { return _M_h.begin(__n); }
+
+      ///@{
+      /**
+       *  @brief  Returns a read-only (constant) iterator pointing to the first
+       *         bucket element.
+       *  @param  __n The bucket index.
+       *  @return  A read-only local iterator.
+       */
+      const_local_iterator
+      begin(size_type __n) const
+      { return _M_h.begin(__n); }
+
+      const_local_iterator
+      cbegin(size_type __n) const
+      { return _M_h.cbegin(__n); }
+      ///@}
+
+      /**
+       *  @brief  Returns a read/write iterator pointing to one past the last
+       *         bucket elements.
+       *  @param  __n The bucket index.
+       *  @return  A read/write local iterator.
+       */
+      local_iterator
+      end(size_type __n)
+      { return _M_h.end(__n); }
+
+      ///@{
+      /**
+       *  @brief  Returns a read-only (constant) iterator pointing to one past
+       *         the last bucket elements.
+       *  @param  __n The bucket index.
+       *  @return  A read-only local iterator.
+       */
+      const_local_iterator
+      end(size_type __n) const
+      { return _M_h.end(__n); }
+
+      const_local_iterator
+      cend(size_type __n) const
+      { return _M_h.cend(__n); }
+      ///@}
+
+      // hash policy.
+
+      /// Returns the average number of elements per bucket.
+      float
+      load_factor() const noexcept
+      { return _M_h.load_factor(); }
+
+      /// Returns a positive number that the %unordered_multimap tries to keep
+      /// the load factor less than or equal to.
+      float
+      max_load_factor() const noexcept
+      { return _M_h.max_load_factor(); }
+
+      /**
+       *  @brief  Change the %unordered_multimap maximum load factor.
+       *  @param  __z The new maximum load factor.
+       */
+      void
+      max_load_factor(float __z)
+      { _M_h.max_load_factor(__z); }
+
+      /**
+       *  @brief  May rehash the %unordered_multimap.
+       *  @param  __n The new number of buckets.
+       *
+       *  Rehash will occur only if the new number of buckets respect the
+       *  %unordered_multimap maximum load factor.
+       */
+      void
+      rehash(size_type __n)
+      { _M_h.rehash(__n); }
+
+      /**
+       *  @brief  Prepare the %unordered_multimap for a specified number of
+       *          elements.
+       *  @param  __n Number of elements required.
+       *
+       *  Same as rehash(ceil(n / max_load_factor())).
+       */
+      void
+      reserve(size_type __n)
+      { _M_h.reserve(__n); }
+
+      template<typename _Key1, typename _Tp1, typename _Hash1, typename _Pred1,
+	       typename _Alloc1>
+        friend bool
+	operator==(const unordered_multimap<_Key1, _Tp1,
+					    _Hash1, _Pred1, _Alloc1>&,
+		   const unordered_multimap<_Key1, _Tp1,
+					    _Hash1, _Pred1, _Alloc1>&);
+    };
+
+#if __cpp_deduction_guides >= 201606
+
+  template<typename _InputIterator,
+	   typename _Hash = hash<__iter_key_t<_InputIterator>>,
+	   typename _Pred = equal_to<__iter_key_t<_InputIterator>>,
+	   typename _Allocator = allocator<__iter_to_alloc_t<_InputIterator>>,
+	   typename = _RequireInputIter<_InputIterator>,
+	   typename = _RequireNotAllocatorOrIntegral<_Hash>,
+	   typename = _RequireNotAllocator<_Pred>,
+	   typename = _RequireAllocator<_Allocator>>
+    unordered_multimap(_InputIterator, _InputIterator,
+		       unordered_multimap<int, int>::size_type = {},
+		       _Hash = _Hash(), _Pred = _Pred(),
+		       _Allocator = _Allocator())
+    -> unordered_multimap<__iter_key_t<_InputIterator>,
+			  __iter_val_t<_InputIterator>, _Hash, _Pred,
+			  _Allocator>;
+
+  template<typename _Key, typename _Tp, typename _Hash = hash<_Key>,
+	   typename _Pred = equal_to<_Key>,
+	   typename _Allocator = allocator<pair<const _Key, _Tp>>,
+	   typename = _RequireNotAllocatorOrIntegral<_Hash>,
+	   typename = _RequireNotAllocator<_Pred>,
+	   typename = _RequireAllocator<_Allocator>>
+    unordered_multimap(initializer_list<pair<_Key, _Tp>>,
+		       unordered_multimap<int, int>::size_type = {},
+		       _Hash = _Hash(), _Pred = _Pred(),
+		       _Allocator = _Allocator())
+    -> unordered_multimap<_Key, _Tp, _Hash, _Pred, _Allocator>;
+
+  template<typename _InputIterator, typename _Allocator,
+	   typename = _RequireInputIter<_InputIterator>,
+	   typename = _RequireAllocator<_Allocator>>
+    unordered_multimap(_InputIterator, _InputIterator,
+		       unordered_multimap<int, int>::size_type, _Allocator)
+    -> unordered_multimap<__iter_key_t<_InputIterator>,
+			  __iter_val_t<_InputIterator>,
+			  hash<__iter_key_t<_InputIterator>>,
+			  equal_to<__iter_key_t<_InputIterator>>, _Allocator>;
+
+  template<typename _InputIterator, typename _Allocator,
+	   typename = _RequireInputIter<_InputIterator>,
+	   typename = _RequireAllocator<_Allocator>>
+    unordered_multimap(_InputIterator, _InputIterator, _Allocator)
+    -> unordered_multimap<__iter_key_t<_InputIterator>,
+			  __iter_val_t<_InputIterator>,
+			  hash<__iter_key_t<_InputIterator>>,
+			  equal_to<__iter_key_t<_InputIterator>>, _Allocator>;
+
+  template<typename _InputIterator, typename _Hash, typename _Allocator,
+	   typename = _RequireInputIter<_InputIterator>,
+	   typename = _RequireNotAllocatorOrIntegral<_Hash>,
+	   typename = _RequireAllocator<_Allocator>>
+    unordered_multimap(_InputIterator, _InputIterator,
+		       unordered_multimap<int, int>::size_type, _Hash,
+		       _Allocator)
+    -> unordered_multimap<__iter_key_t<_InputIterator>,
+			  __iter_val_t<_InputIterator>, _Hash,
+			  equal_to<__iter_key_t<_InputIterator>>, _Allocator>;
+
+  template<typename _Key, typename _Tp, typename _Allocator,
+	   typename = _RequireAllocator<_Allocator>>
+    unordered_multimap(initializer_list<pair<_Key, _Tp>>,
+		       unordered_multimap<int, int>::size_type,
+		       _Allocator)
+    -> unordered_multimap<_Key, _Tp, hash<_Key>, equal_to<_Key>, _Allocator>;
+
+  template<typename _Key, typename _Tp, typename _Allocator,
+	   typename = _RequireAllocator<_Allocator>>
+    unordered_multimap(initializer_list<pair<_Key, _Tp>>, _Allocator)
+    -> unordered_multimap<_Key, _Tp, hash<_Key>, equal_to<_Key>, _Allocator>;
+
+  template<typename _Key, typename _Tp, typename _Hash, typename _Allocator,
+	   typename = _RequireNotAllocatorOrIntegral<_Hash>,
+	   typename = _RequireAllocator<_Allocator>>
+    unordered_multimap(initializer_list<pair<_Key, _Tp>>,
+		       unordered_multimap<int, int>::size_type,
+		       _Hash, _Allocator)
+    -> unordered_multimap<_Key, _Tp, _Hash, equal_to<_Key>, _Allocator>;
+
+#endif
+
+  template<class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+    inline void
+    swap(unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>& __x,
+	 unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>& __y)
+    noexcept(noexcept(__x.swap(__y)))
+    { __x.swap(__y); }
+
+  template<class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+    inline void
+    swap(unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>& __x,
+	 unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>& __y)
+    noexcept(noexcept(__x.swap(__y)))
+    { __x.swap(__y); }
+
+  template<class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+    inline bool
+    operator==(const unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>& __x,
+	       const unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>& __y)
+    { return __x._M_h._M_equal(__y._M_h); }
+
+#if __cpp_impl_three_way_comparison < 201907L
+  template<class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+    inline bool
+    operator!=(const unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>& __x,
+	       const unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>& __y)
+    { return !(__x == __y); }
+#endif
+
+  template<class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+    inline bool
+    operator==(const unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>& __x,
+	       const unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>& __y)
+    { return __x._M_h._M_equal(__y._M_h); }
+
+#if __cpp_impl_three_way_comparison < 201907L
+  template<class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+    inline bool
+    operator!=(const unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>& __x,
+	       const unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>& __y)
+    { return !(__x == __y); }
+#endif
+
+_GLIBCXX_END_NAMESPACE_CONTAINER
+
+#if __cplusplus > 201402L
+  // Allow std::unordered_map access to internals of compatible maps.
+  template<typename _Key, typename _Val, typename _Hash1, typename _Eq1,
+	   typename _Alloc, typename _Hash2, typename _Eq2>
+    struct _Hash_merge_helper<
+      _GLIBCXX_STD_C::unordered_map<_Key, _Val, _Hash1, _Eq1, _Alloc>,
+      _Hash2, _Eq2>
+    {
+    private:
+      template<typename... _Tp>
+	using unordered_map = _GLIBCXX_STD_C::unordered_map<_Tp...>;
+      template<typename... _Tp>
+	using unordered_multimap = _GLIBCXX_STD_C::unordered_multimap<_Tp...>;
+
+      friend unordered_map<_Key, _Val, _Hash1, _Eq1, _Alloc>;
+
+      static auto&
+      _S_get_table(unordered_map<_Key, _Val, _Hash2, _Eq2, _Alloc>& __map)
+      { return __map._M_h; }
+
+      static auto&
+      _S_get_table(unordered_multimap<_Key, _Val, _Hash2, _Eq2, _Alloc>& __map)
+      { return __map._M_h; }
+    };
+
+  // Allow std::unordered_multimap access to internals of compatible maps.
+  template<typename _Key, typename _Val, typename _Hash1, typename _Eq1,
+	   typename _Alloc, typename _Hash2, typename _Eq2>
+    struct _Hash_merge_helper<
+      _GLIBCXX_STD_C::unordered_multimap<_Key, _Val, _Hash1, _Eq1, _Alloc>,
+      _Hash2, _Eq2>
+    {
+    private:
+      template<typename... _Tp>
+	using unordered_map = _GLIBCXX_STD_C::unordered_map<_Tp...>;
+      template<typename... _Tp>
+	using unordered_multimap = _GLIBCXX_STD_C::unordered_multimap<_Tp...>;
+
+      friend unordered_multimap<_Key, _Val, _Hash1, _Eq1, _Alloc>;
+
+      static auto&
+      _S_get_table(unordered_map<_Key, _Val, _Hash2, _Eq2, _Alloc>& __map)
+      { return __map._M_h; }
+
+      static auto&
+      _S_get_table(unordered_multimap<_Key, _Val, _Hash2, _Eq2, _Alloc>& __map)
+      { return __map._M_h; }
+    };
+#endif // C++17
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif /* _UNORDERED_MAP_H */
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@@ -0,0 +1,1884 @@
+// unordered_set implementation -*- C++ -*-
+
+// Copyright (C) 2010-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/unordered_set.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{unordered_set}
+ */
+
+#ifndef _UNORDERED_SET_H
+#define _UNORDERED_SET_H
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+_GLIBCXX_BEGIN_NAMESPACE_CONTAINER
+
+  /// Base types for unordered_set.
+  template<bool _Cache>
+    using __uset_traits = __detail::_Hashtable_traits<_Cache, true, true>;
+
+  template<typename _Value,
+	   typename _Hash = hash<_Value>,
+	   typename _Pred = std::equal_to<_Value>,
+  	   typename _Alloc = std::allocator<_Value>,
+	   typename _Tr = __uset_traits<__cache_default<_Value, _Hash>::value>>
+    using __uset_hashtable = _Hashtable<_Value, _Value, _Alloc,
+					__detail::_Identity, _Pred, _Hash,
+					__detail::_Mod_range_hashing,
+					__detail::_Default_ranged_hash,
+					__detail::_Prime_rehash_policy, _Tr>;
+
+  /// Base types for unordered_multiset.
+  template<bool _Cache>
+    using __umset_traits = __detail::_Hashtable_traits<_Cache, true, false>;
+
+  template<typename _Value,
+	   typename _Hash = hash<_Value>,
+	   typename _Pred = std::equal_to<_Value>,
+	   typename _Alloc = std::allocator<_Value>,
+	   typename _Tr = __umset_traits<__cache_default<_Value, _Hash>::value>>
+    using __umset_hashtable = _Hashtable<_Value, _Value, _Alloc,
+					 __detail::_Identity,
+					 _Pred, _Hash,
+					 __detail::_Mod_range_hashing,
+					 __detail::_Default_ranged_hash,
+					 __detail::_Prime_rehash_policy, _Tr>;
+
+  template<class _Value, class _Hash, class _Pred, class _Alloc>
+    class unordered_multiset;
+
+  /**
+   *  @brief A standard container composed of unique keys (containing
+   *  at most one of each key value) in which the elements' keys are
+   *  the elements themselves.
+   *
+   *  @ingroup unordered_associative_containers
+   *
+   *  @tparam  _Value  Type of key objects.
+   *  @tparam  _Hash  Hashing function object type, defaults to hash<_Value>.
+
+   *  @tparam _Pred Predicate function object type, defaults to
+   *                equal_to<_Value>.
+   *
+   *  @tparam  _Alloc  Allocator type, defaults to allocator<_Key>.
+   *
+   *  Meets the requirements of a <a href="tables.html#65">container</a>, and
+   *  <a href="tables.html#xx">unordered associative container</a>
+   *
+   *  Base is _Hashtable, dispatched at compile time via template
+   *  alias __uset_hashtable.
+   */
+  template<typename _Value,
+	   typename _Hash = hash<_Value>,
+	   typename _Pred = equal_to<_Value>,
+	   typename _Alloc = allocator<_Value>>
+    class unordered_set
+    {
+      typedef __uset_hashtable<_Value, _Hash, _Pred, _Alloc>  _Hashtable;
+      _Hashtable _M_h;
+
+    public:
+      // typedefs:
+      ///@{
+      /// Public typedefs.
+      typedef typename _Hashtable::key_type	key_type;
+      typedef typename _Hashtable::value_type	value_type;
+      typedef typename _Hashtable::hasher	hasher;
+      typedef typename _Hashtable::key_equal	key_equal;
+      typedef typename _Hashtable::allocator_type allocator_type;
+      ///@}
+
+      ///@{
+      ///  Iterator-related typedefs.
+      typedef typename _Hashtable::pointer		pointer;
+      typedef typename _Hashtable::const_pointer	const_pointer;
+      typedef typename _Hashtable::reference		reference;
+      typedef typename _Hashtable::const_reference	const_reference;
+      typedef typename _Hashtable::iterator		iterator;
+      typedef typename _Hashtable::const_iterator	const_iterator;
+      typedef typename _Hashtable::local_iterator	local_iterator;
+      typedef typename _Hashtable::const_local_iterator	const_local_iterator;
+      typedef typename _Hashtable::size_type		size_type;
+      typedef typename _Hashtable::difference_type	difference_type;
+      ///@}
+
+#if __cplusplus > 201402L
+      using node_type = typename _Hashtable::node_type;
+      using insert_return_type = typename _Hashtable::insert_return_type;
+#endif
+
+      // construct/destroy/copy
+
+      /// Default constructor.
+      unordered_set() = default;
+
+      /**
+       *  @brief  Default constructor creates no elements.
+       *  @param __n  Minimal initial number of buckets.
+       *  @param __hf  A hash functor.
+       *  @param __eql  A key equality functor.
+       *  @param __a  An allocator object.
+       */
+      explicit
+      unordered_set(size_type __n,
+		    const hasher& __hf = hasher(),
+		    const key_equal& __eql = key_equal(),
+		    const allocator_type& __a = allocator_type())
+      : _M_h(__n, __hf, __eql, __a)
+      { }
+
+      /**
+       *  @brief  Builds an %unordered_set from a range.
+       *  @param  __first  An input iterator.
+       *  @param  __last  An input iterator.
+       *  @param __n  Minimal initial number of buckets.
+       *  @param __hf  A hash functor.
+       *  @param __eql  A key equality functor.
+       *  @param __a  An allocator object.
+       *
+       *  Create an %unordered_set consisting of copies of the elements from
+       *  [__first,__last).  This is linear in N (where N is
+       *  distance(__first,__last)).
+       */
+      template<typename _InputIterator>
+	unordered_set(_InputIterator __first, _InputIterator __last,
+		      size_type __n = 0,
+		      const hasher& __hf = hasher(),
+		      const key_equal& __eql = key_equal(),
+		      const allocator_type& __a = allocator_type())
+	: _M_h(__first, __last, __n, __hf, __eql, __a)
+	{ }
+
+      /// Copy constructor.
+      unordered_set(const unordered_set&) = default;
+
+      /// Move constructor.
+      unordered_set(unordered_set&&) = default;
+
+      /**
+       *  @brief Creates an %unordered_set with no elements.
+       *  @param __a An allocator object.
+       */
+      explicit
+      unordered_set(const allocator_type& __a)
+      : _M_h(__a)
+      { }
+
+      /*
+       *  @brief Copy constructor with allocator argument.
+       * @param  __uset  Input %unordered_set to copy.
+       * @param  __a  An allocator object.
+       */
+      unordered_set(const unordered_set& __uset,
+		    const allocator_type& __a)
+      : _M_h(__uset._M_h, __a)
+      { }
+
+      /*
+       *  @brief  Move constructor with allocator argument.
+       *  @param  __uset Input %unordered_set to move.
+       *  @param  __a    An allocator object.
+       */
+      unordered_set(unordered_set&& __uset,
+		    const allocator_type& __a)
+	noexcept( noexcept(_Hashtable(std::move(__uset._M_h), __a)) )
+      : _M_h(std::move(__uset._M_h), __a)
+      { }
+
+      /**
+       *  @brief  Builds an %unordered_set from an initializer_list.
+       *  @param  __l  An initializer_list.
+       *  @param __n  Minimal initial number of buckets.
+       *  @param __hf  A hash functor.
+       *  @param __eql  A key equality functor.
+       *  @param  __a  An allocator object.
+       *
+       *  Create an %unordered_set consisting of copies of the elements in the
+       *  list. This is linear in N (where N is @a __l.size()).
+       */
+      unordered_set(initializer_list<value_type> __l,
+		    size_type __n = 0,
+		    const hasher& __hf = hasher(),
+		    const key_equal& __eql = key_equal(),
+		    const allocator_type& __a = allocator_type())
+      : _M_h(__l, __n, __hf, __eql, __a)
+      { }
+
+      unordered_set(size_type __n, const allocator_type& __a)
+      : unordered_set(__n, hasher(), key_equal(), __a)
+      { }
+
+      unordered_set(size_type __n, const hasher& __hf,
+		    const allocator_type& __a)
+      : unordered_set(__n, __hf, key_equal(), __a)
+      { }
+
+      template<typename _InputIterator>
+	unordered_set(_InputIterator __first, _InputIterator __last,
+		      size_type __n,
+		      const allocator_type& __a)
+	: unordered_set(__first, __last, __n, hasher(), key_equal(), __a)
+	{ }
+
+      template<typename _InputIterator>
+	unordered_set(_InputIterator __first, _InputIterator __last,
+		      size_type __n, const hasher& __hf,
+		      const allocator_type& __a)
+	: unordered_set(__first, __last, __n, __hf, key_equal(), __a)
+	{ }
+
+      unordered_set(initializer_list<value_type> __l,
+		    size_type __n,
+		    const allocator_type& __a)
+      : unordered_set(__l, __n, hasher(), key_equal(), __a)
+      { }
+
+      unordered_set(initializer_list<value_type> __l,
+		    size_type __n, const hasher& __hf,
+		    const allocator_type& __a)
+      : unordered_set(__l, __n, __hf, key_equal(), __a)
+      { }
+
+      /// Copy assignment operator.
+      unordered_set&
+      operator=(const unordered_set&) = default;
+
+      /// Move assignment operator.
+      unordered_set&
+      operator=(unordered_set&&) = default;
+
+      /**
+       *  @brief  %Unordered_set list assignment operator.
+       *  @param  __l  An initializer_list.
+       *
+       *  This function fills an %unordered_set with copies of the elements in
+       *  the initializer list @a __l.
+       *
+       *  Note that the assignment completely changes the %unordered_set and
+       *  that the resulting %unordered_set's size is the same as the number
+       *  of elements assigned.
+       */
+      unordered_set&
+      operator=(initializer_list<value_type> __l)
+      {
+	_M_h = __l;
+	return *this;
+      }
+
+      ///  Returns the allocator object used by the %unordered_set.
+      allocator_type
+      get_allocator() const noexcept
+      { return _M_h.get_allocator(); }
+
+      // size and capacity:
+
+      ///  Returns true if the %unordered_set is empty.
+      _GLIBCXX_NODISCARD bool
+      empty() const noexcept
+      { return _M_h.empty(); }
+
+      ///  Returns the size of the %unordered_set.
+      size_type
+      size() const noexcept
+      { return _M_h.size(); }
+
+      ///  Returns the maximum size of the %unordered_set.
+      size_type
+      max_size() const noexcept
+      { return _M_h.max_size(); }
+
+      // iterators.
+
+      ///@{
+      /**
+       *  Returns a read-only (constant) iterator that points to the first
+       *  element in the %unordered_set.
+       */
+      iterator
+      begin() noexcept
+      { return _M_h.begin(); }
+
+      const_iterator
+      begin() const noexcept
+      { return _M_h.begin(); }
+      ///@}
+
+      ///@{
+      /**
+       *  Returns a read-only (constant) iterator that points one past the last
+       *  element in the %unordered_set.
+       */
+      iterator
+      end() noexcept
+      { return _M_h.end(); }
+
+      const_iterator
+      end() const noexcept
+      { return _M_h.end(); }
+      ///@}
+
+      /**
+       *  Returns a read-only (constant) iterator that points to the first
+       *  element in the %unordered_set.
+       */
+      const_iterator
+      cbegin() const noexcept
+      { return _M_h.begin(); }
+
+      /**
+       *  Returns a read-only (constant) iterator that points one past the last
+       *  element in the %unordered_set.
+       */
+      const_iterator
+      cend() const noexcept
+      { return _M_h.end(); }
+
+      // modifiers.
+
+      /**
+       *  @brief Attempts to build and insert an element into the
+       *  %unordered_set.
+       *  @param __args  Arguments used to generate an element.
+       *  @return  A pair, of which the first element is an iterator that points
+       *           to the possibly inserted element, and the second is a bool
+       *           that is true if the element was actually inserted.
+       *
+       *  This function attempts to build and insert an element into the
+       *  %unordered_set. An %unordered_set relies on unique keys and thus an
+       *  element is only inserted if it is not already present in the
+       *  %unordered_set.
+       *
+       *  Insertion requires amortized constant time.
+       */
+      template<typename... _Args>
+	std::pair<iterator, bool>
+	emplace(_Args&&... __args)
+	{ return _M_h.emplace(std::forward<_Args>(__args)...); }
+
+      /**
+       *  @brief Attempts to insert an element into the %unordered_set.
+       *  @param  __pos  An iterator that serves as a hint as to where the
+       *                element should be inserted.
+       *  @param  __args  Arguments used to generate the element to be
+       *                 inserted.
+       *  @return An iterator that points to the element with key equivalent to
+       *          the one generated from @a __args (may or may not be the
+       *          element itself).
+       *
+       *  This function is not concerned about whether the insertion took place,
+       *  and thus does not return a boolean like the single-argument emplace()
+       *  does.  Note that the first parameter is only a hint and can
+       *  potentially improve the performance of the insertion process.  A bad
+       *  hint would cause no gains in efficiency.
+       *
+       *  For more on @a hinting, see:
+       *  https://gcc.gnu.org/onlinedocs/libstdc++/manual/associative.html#containers.associative.insert_hints
+       *
+       *  Insertion requires amortized constant time.
+       */
+      template<typename... _Args>
+	iterator
+	emplace_hint(const_iterator __pos, _Args&&... __args)
+	{ return _M_h.emplace_hint(__pos, std::forward<_Args>(__args)...); }
+
+      ///@{
+      /**
+       *  @brief Attempts to insert an element into the %unordered_set.
+       *  @param  __x  Element to be inserted.
+       *  @return  A pair, of which the first element is an iterator that points
+       *           to the possibly inserted element, and the second is a bool
+       *           that is true if the element was actually inserted.
+       *
+       *  This function attempts to insert an element into the %unordered_set.
+       *  An %unordered_set relies on unique keys and thus an element is only
+       *  inserted if it is not already present in the %unordered_set.
+       *
+       *  Insertion requires amortized constant time.
+       */
+      std::pair<iterator, bool>
+      insert(const value_type& __x)
+      { return _M_h.insert(__x); }
+
+      std::pair<iterator, bool>
+      insert(value_type&& __x)
+      { return _M_h.insert(std::move(__x)); }
+      ///@}
+
+      ///@{
+      /**
+       *  @brief Attempts to insert an element into the %unordered_set.
+       *  @param  __hint  An iterator that serves as a hint as to where the
+       *                 element should be inserted.
+       *  @param  __x  Element to be inserted.
+       *  @return An iterator that points to the element with key of
+       *           @a __x (may or may not be the element passed in).
+       *
+       *  This function is not concerned about whether the insertion took place,
+       *  and thus does not return a boolean like the single-argument insert()
+       *  does.  Note that the first parameter is only a hint and can
+       *  potentially improve the performance of the insertion process.  A bad
+       *  hint would cause no gains in efficiency.
+       *
+       *  For more on @a hinting, see:
+       *  https://gcc.gnu.org/onlinedocs/libstdc++/manual/associative.html#containers.associative.insert_hints
+       *
+       *  Insertion requires amortized constant.
+       */
+      iterator
+      insert(const_iterator __hint, const value_type& __x)
+      { return _M_h.insert(__hint, __x); }
+
+      iterator
+      insert(const_iterator __hint, value_type&& __x)
+      { return _M_h.insert(__hint, std::move(__x)); }
+      ///@}
+
+      /**
+       *  @brief A template function that attempts to insert a range of
+       *  elements.
+       *  @param  __first  Iterator pointing to the start of the range to be
+       *                   inserted.
+       *  @param  __last  Iterator pointing to the end of the range.
+       *
+       *  Complexity similar to that of the range constructor.
+       */
+      template<typename _InputIterator>
+	void
+	insert(_InputIterator __first, _InputIterator __last)
+	{ _M_h.insert(__first, __last); }
+
+      /**
+       *  @brief Attempts to insert a list of elements into the %unordered_set.
+       *  @param  __l  A std::initializer_list<value_type> of elements
+       *               to be inserted.
+       *
+       *  Complexity similar to that of the range constructor.
+       */
+      void
+      insert(initializer_list<value_type> __l)
+      { _M_h.insert(__l); }
+
+#if __cplusplus > 201402L
+      /// Extract a node.
+      node_type
+      extract(const_iterator __pos)
+      {
+	__glibcxx_assert(__pos != end());
+	return _M_h.extract(__pos);
+      }
+
+      /// Extract a node.
+      node_type
+      extract(const key_type& __key)
+      { return _M_h.extract(__key); }
+
+      /// Re-insert an extracted node.
+      insert_return_type
+      insert(node_type&& __nh)
+      { return _M_h._M_reinsert_node(std::move(__nh)); }
+
+      /// Re-insert an extracted node.
+      iterator
+      insert(const_iterator, node_type&& __nh)
+      { return _M_h._M_reinsert_node(std::move(__nh)).position; }
+#endif // C++17
+
+      ///@{
+      /**
+       *  @brief Erases an element from an %unordered_set.
+       *  @param  __position  An iterator pointing to the element to be erased.
+       *  @return An iterator pointing to the element immediately following
+       *          @a __position prior to the element being erased. If no such
+       *          element exists, end() is returned.
+       *
+       *  This function erases an element, pointed to by the given iterator,
+       *  from an %unordered_set.  Note that this function only erases the
+       *  element, and that if the element is itself a pointer, the pointed-to
+       *  memory is not touched in any way.  Managing the pointer is the user's
+       *  responsibility.
+       */
+      iterator
+      erase(const_iterator __position)
+      { return _M_h.erase(__position); }
+
+      // LWG 2059.
+      iterator
+      erase(iterator __position)
+      { return _M_h.erase(__position); }
+      ///@}
+
+      /**
+       *  @brief Erases elements according to the provided key.
+       *  @param  __x  Key of element to be erased.
+       *  @return  The number of elements erased.
+       *
+       *  This function erases all the elements located by the given key from
+       *  an %unordered_set. For an %unordered_set the result of this function
+       *  can only be 0 (not present) or 1 (present).
+       *  Note that this function only erases the element, and that if
+       *  the element is itself a pointer, the pointed-to memory is not touched
+       *  in any way.  Managing the pointer is the user's responsibility.
+       */
+      size_type
+      erase(const key_type& __x)
+      { return _M_h.erase(__x); }
+
+      /**
+       *  @brief Erases a [__first,__last) range of elements from an
+       *  %unordered_set.
+       *  @param  __first  Iterator pointing to the start of the range to be
+       *                  erased.
+       *  @param __last  Iterator pointing to the end of the range to
+       *                be erased.
+       *  @return The iterator @a __last.
+       *
+       *  This function erases a sequence of elements from an %unordered_set.
+       *  Note that this function only erases the element, and that if
+       *  the element is itself a pointer, the pointed-to memory is not touched
+       *  in any way.  Managing the pointer is the user's responsibility.
+       */
+      iterator
+      erase(const_iterator __first, const_iterator __last)
+      { return _M_h.erase(__first, __last); }
+
+      /**
+       *  Erases all elements in an %unordered_set. Note that this function only
+       *  erases the elements, and that if the elements themselves are pointers,
+       *  the pointed-to memory is not touched in any way. Managing the pointer
+       *  is the user's responsibility.
+       */
+      void
+      clear() noexcept
+      { _M_h.clear(); }
+
+      /**
+       *  @brief  Swaps data with another %unordered_set.
+       *  @param  __x  An %unordered_set of the same element and allocator
+       *  types.
+       *
+       *  This exchanges the elements between two sets in constant time.
+       *  Note that the global std::swap() function is specialized such that
+       *  std::swap(s1,s2) will feed to this function.
+       */
+      void
+      swap(unordered_set& __x)
+      noexcept( noexcept(_M_h.swap(__x._M_h)) )
+      { _M_h.swap(__x._M_h); }
+
+#if __cplusplus > 201402L
+      template<typename, typename, typename>
+	friend class std::_Hash_merge_helper;
+
+      template<typename _H2, typename _P2>
+	void
+	merge(unordered_set<_Value, _H2, _P2, _Alloc>& __source)
+	{
+	  using _Merge_helper = _Hash_merge_helper<unordered_set, _H2, _P2>;
+	  _M_h._M_merge_unique(_Merge_helper::_S_get_table(__source));
+	}
+
+      template<typename _H2, typename _P2>
+	void
+	merge(unordered_set<_Value, _H2, _P2, _Alloc>&& __source)
+	{ merge(__source); }
+
+      template<typename _H2, typename _P2>
+	void
+	merge(unordered_multiset<_Value, _H2, _P2, _Alloc>& __source)
+	{
+	  using _Merge_helper = _Hash_merge_helper<unordered_set, _H2, _P2>;
+	  _M_h._M_merge_unique(_Merge_helper::_S_get_table(__source));
+	}
+
+      template<typename _H2, typename _P2>
+	void
+	merge(unordered_multiset<_Value, _H2, _P2, _Alloc>&& __source)
+	{ merge(__source); }
+#endif // C++17
+
+      // observers.
+
+      ///  Returns the hash functor object with which the %unordered_set was
+      ///  constructed.
+      hasher
+      hash_function() const
+      { return _M_h.hash_function(); }
+
+      ///  Returns the key comparison object with which the %unordered_set was
+      ///  constructed.
+      key_equal
+      key_eq() const
+      { return _M_h.key_eq(); }
+
+      // lookup.
+
+      ///@{
+      /**
+       *  @brief Tries to locate an element in an %unordered_set.
+       *  @param  __x  Element to be located.
+       *  @return  Iterator pointing to sought-after element, or end() if not
+       *           found.
+       *
+       *  This function takes a key and tries to locate the element with which
+       *  the key matches.  If successful the function returns an iterator
+       *  pointing to the sought after element.  If unsuccessful it returns the
+       *  past-the-end ( @c end() ) iterator.
+       */
+      iterator
+      find(const key_type& __x)
+      { return _M_h.find(__x); }
+
+#if __cplusplus > 201703L
+      template<typename _Kt>
+	auto
+	find(const _Kt& __k)
+	-> decltype(_M_h._M_find_tr(__k))
+	{ return _M_h._M_find_tr(__k); }
+#endif
+
+      const_iterator
+      find(const key_type& __x) const
+      { return _M_h.find(__x); }
+
+#if __cplusplus > 201703L
+      template<typename _Kt>
+	auto
+	find(const _Kt& __k) const
+	-> decltype(_M_h._M_find_tr(__k))
+	{ return _M_h._M_find_tr(__k); }
+#endif
+      ///@}
+
+      ///@{
+      /**
+       *  @brief  Finds the number of elements.
+       *  @param  __x  Element to located.
+       *  @return  Number of elements with specified key.
+       *
+       *  This function only makes sense for unordered_multisets; for
+       *  unordered_set the result will either be 0 (not present) or 1
+       *  (present).
+       */
+      size_type
+      count(const key_type& __x) const
+      { return _M_h.count(__x); }
+
+#if __cplusplus > 201703L
+      template<typename _Kt>
+	auto
+	count(const _Kt& __k) const
+	-> decltype(_M_h._M_count_tr(__k))
+	{ return _M_h._M_count_tr(__k); }
+#endif
+      ///@}
+
+#if __cplusplus > 201703L
+      ///@{
+      /**
+       *  @brief  Finds whether an element with the given key exists.
+       *  @param  __x  Key of elements to be located.
+       *  @return  True if there is any element with the specified key.
+       */
+      bool
+      contains(const key_type& __x) const
+      { return _M_h.find(__x) != _M_h.end(); }
+
+      template<typename _Kt>
+	auto
+	contains(const _Kt& __k) const
+	-> decltype(_M_h._M_find_tr(__k), void(), true)
+	{ return _M_h._M_find_tr(__k) != _M_h.end(); }
+      ///@}
+#endif
+
+      ///@{
+      /**
+       *  @brief Finds a subsequence matching given key.
+       *  @param  __x  Key to be located.
+       *  @return  Pair of iterators that possibly points to the subsequence
+       *           matching given key.
+       *
+       *  This function probably only makes sense for multisets.
+       */
+      std::pair<iterator, iterator>
+      equal_range(const key_type& __x)
+      { return _M_h.equal_range(__x); }
+
+#if __cplusplus > 201703L
+      template<typename _Kt>
+	auto
+	equal_range(const _Kt& __k)
+	-> decltype(_M_h._M_equal_range_tr(__k))
+	{ return _M_h._M_equal_range_tr(__k); }
+#endif
+
+      std::pair<const_iterator, const_iterator>
+      equal_range(const key_type& __x) const
+      { return _M_h.equal_range(__x); }
+
+#if __cplusplus > 201703L
+      template<typename _Kt>
+	auto
+	equal_range(const _Kt& __k) const
+	-> decltype(_M_h._M_equal_range_tr(__k))
+	{ return _M_h._M_equal_range_tr(__k); }
+#endif
+      ///@}
+
+      // bucket interface.
+
+      /// Returns the number of buckets of the %unordered_set.
+      size_type
+      bucket_count() const noexcept
+      { return _M_h.bucket_count(); }
+
+      /// Returns the maximum number of buckets of the %unordered_set.
+      size_type
+      max_bucket_count() const noexcept
+      { return _M_h.max_bucket_count(); }
+
+      /*
+       * @brief  Returns the number of elements in a given bucket.
+       * @param  __n  A bucket index.
+       * @return  The number of elements in the bucket.
+       */
+      size_type
+      bucket_size(size_type __n) const
+      { return _M_h.bucket_size(__n); }
+
+      /*
+       * @brief  Returns the bucket index of a given element.
+       * @param  __key  A key instance.
+       * @return  The key bucket index.
+       */
+      size_type
+      bucket(const key_type& __key) const
+      { return _M_h.bucket(__key); }
+
+      ///@{
+      /**
+       *  @brief  Returns a read-only (constant) iterator pointing to the first
+       *         bucket element.
+       *  @param  __n The bucket index.
+       *  @return  A read-only local iterator.
+       */
+      local_iterator
+      begin(size_type __n)
+      { return _M_h.begin(__n); }
+
+      const_local_iterator
+      begin(size_type __n) const
+      { return _M_h.begin(__n); }
+
+      const_local_iterator
+      cbegin(size_type __n) const
+      { return _M_h.cbegin(__n); }
+      ///@}
+
+      ///@{
+      /**
+       *  @brief  Returns a read-only (constant) iterator pointing to one past
+       *         the last bucket elements.
+       *  @param  __n The bucket index.
+       *  @return  A read-only local iterator.
+       */
+      local_iterator
+      end(size_type __n)
+      { return _M_h.end(__n); }
+
+      const_local_iterator
+      end(size_type __n) const
+      { return _M_h.end(__n); }
+
+      const_local_iterator
+      cend(size_type __n) const
+      { return _M_h.cend(__n); }
+      ///@}
+
+      // hash policy.
+
+      /// Returns the average number of elements per bucket.
+      float
+      load_factor() const noexcept
+      { return _M_h.load_factor(); }
+
+      /// Returns a positive number that the %unordered_set tries to keep the
+      /// load factor less than or equal to.
+      float
+      max_load_factor() const noexcept
+      { return _M_h.max_load_factor(); }
+
+      /**
+       *  @brief  Change the %unordered_set maximum load factor.
+       *  @param  __z The new maximum load factor.
+       */
+      void
+      max_load_factor(float __z)
+      { _M_h.max_load_factor(__z); }
+
+      /**
+       *  @brief  May rehash the %unordered_set.
+       *  @param  __n The new number of buckets.
+       *
+       *  Rehash will occur only if the new number of buckets respect the
+       *  %unordered_set maximum load factor.
+       */
+      void
+      rehash(size_type __n)
+      { _M_h.rehash(__n); }
+
+      /**
+       *  @brief  Prepare the %unordered_set for a specified number of
+       *          elements.
+       *  @param  __n Number of elements required.
+       *
+       *  Same as rehash(ceil(n / max_load_factor())).
+       */
+      void
+      reserve(size_type __n)
+      { _M_h.reserve(__n); }
+
+      template<typename _Value1, typename _Hash1, typename _Pred1,
+	       typename _Alloc1>
+        friend bool
+        operator==(const unordered_set<_Value1, _Hash1, _Pred1, _Alloc1>&,
+		   const unordered_set<_Value1, _Hash1, _Pred1, _Alloc1>&);
+    };
+
+#if __cpp_deduction_guides >= 201606
+
+  template<typename _InputIterator,
+	   typename _Hash =
+	     hash<typename iterator_traits<_InputIterator>::value_type>,
+	   typename _Pred =
+	     equal_to<typename iterator_traits<_InputIterator>::value_type>,
+	   typename _Allocator =
+	     allocator<typename iterator_traits<_InputIterator>::value_type>,
+	   typename = _RequireInputIter<_InputIterator>,
+	   typename = _RequireNotAllocatorOrIntegral<_Hash>,
+	   typename = _RequireNotAllocator<_Pred>,
+	   typename = _RequireAllocator<_Allocator>>
+    unordered_set(_InputIterator, _InputIterator,
+		  unordered_set<int>::size_type = {},
+		  _Hash = _Hash(), _Pred = _Pred(), _Allocator = _Allocator())
+    -> unordered_set<typename iterator_traits<_InputIterator>::value_type,
+		     _Hash, _Pred, _Allocator>;
+
+  template<typename _Tp, typename _Hash = hash<_Tp>,
+	   typename _Pred = equal_to<_Tp>,
+	   typename _Allocator = allocator<_Tp>,
+	   typename = _RequireNotAllocatorOrIntegral<_Hash>,
+	   typename = _RequireNotAllocator<_Pred>,
+	   typename = _RequireAllocator<_Allocator>>
+    unordered_set(initializer_list<_Tp>,
+		  unordered_set<int>::size_type = {},
+		  _Hash = _Hash(), _Pred = _Pred(), _Allocator = _Allocator())
+    -> unordered_set<_Tp, _Hash, _Pred, _Allocator>;
+
+  template<typename _InputIterator, typename _Allocator,
+	   typename = _RequireInputIter<_InputIterator>,
+	   typename = _RequireAllocator<_Allocator>>
+    unordered_set(_InputIterator, _InputIterator,
+		  unordered_set<int>::size_type, _Allocator)
+    -> unordered_set<typename iterator_traits<_InputIterator>::value_type,
+		     hash<
+		       typename iterator_traits<_InputIterator>::value_type>,
+		     equal_to<
+		       typename iterator_traits<_InputIterator>::value_type>,
+		     _Allocator>;
+
+  template<typename _InputIterator, typename _Hash, typename _Allocator,
+	   typename = _RequireInputIter<_InputIterator>,
+	   typename = _RequireNotAllocatorOrIntegral<_Hash>,
+	   typename = _RequireAllocator<_Allocator>>
+    unordered_set(_InputIterator, _InputIterator,
+		  unordered_set<int>::size_type,
+		  _Hash, _Allocator)
+    -> unordered_set<typename iterator_traits<_InputIterator>::value_type,
+		     _Hash,
+		     equal_to<
+		       typename iterator_traits<_InputIterator>::value_type>,
+		     _Allocator>;
+
+  template<typename _Tp, typename _Allocator,
+	   typename = _RequireAllocator<_Allocator>>
+    unordered_set(initializer_list<_Tp>,
+		  unordered_set<int>::size_type, _Allocator)
+    -> unordered_set<_Tp, hash<_Tp>, equal_to<_Tp>, _Allocator>;
+
+  template<typename _Tp, typename _Hash, typename _Allocator,
+	   typename = _RequireNotAllocatorOrIntegral<_Hash>,
+	   typename = _RequireAllocator<_Allocator>>
+    unordered_set(initializer_list<_Tp>,
+		  unordered_set<int>::size_type, _Hash, _Allocator)
+    -> unordered_set<_Tp, _Hash, equal_to<_Tp>, _Allocator>;
+
+#endif
+
+  /**
+   *  @brief A standard container composed of equivalent keys
+   *  (possibly containing multiple of each key value) in which the
+   *  elements' keys are the elements themselves.
+   *
+   *  @ingroup unordered_associative_containers
+   *
+   *  @tparam  _Value  Type of key objects.
+   *  @tparam  _Hash  Hashing function object type, defaults to hash<_Value>.
+   *  @tparam  _Pred  Predicate function object type, defaults
+   *                  to equal_to<_Value>.
+   *  @tparam  _Alloc  Allocator type, defaults to allocator<_Key>.
+   *
+   *  Meets the requirements of a <a href="tables.html#65">container</a>, and
+   *  <a href="tables.html#xx">unordered associative container</a>
+   *
+   *  Base is _Hashtable, dispatched at compile time via template
+   *  alias __umset_hashtable.
+   */
+  template<typename _Value,
+	   typename _Hash = hash<_Value>,
+	   typename _Pred = equal_to<_Value>,
+	   typename _Alloc = allocator<_Value>>
+    class unordered_multiset
+    {
+      typedef __umset_hashtable<_Value, _Hash, _Pred, _Alloc>  _Hashtable;
+      _Hashtable _M_h;
+
+    public:
+      // typedefs:
+      ///@{
+      /// Public typedefs.
+      typedef typename _Hashtable::key_type	key_type;
+      typedef typename _Hashtable::value_type	value_type;
+      typedef typename _Hashtable::hasher	hasher;
+      typedef typename _Hashtable::key_equal	key_equal;
+      typedef typename _Hashtable::allocator_type allocator_type;
+      ///@}
+
+      ///@{
+      ///  Iterator-related typedefs.
+      typedef typename _Hashtable::pointer		pointer;
+      typedef typename _Hashtable::const_pointer	const_pointer;
+      typedef typename _Hashtable::reference		reference;
+      typedef typename _Hashtable::const_reference	const_reference;
+      typedef typename _Hashtable::iterator		iterator;
+      typedef typename _Hashtable::const_iterator	const_iterator;
+      typedef typename _Hashtable::local_iterator	local_iterator;
+      typedef typename _Hashtable::const_local_iterator	const_local_iterator;
+      typedef typename _Hashtable::size_type		size_type;
+      typedef typename _Hashtable::difference_type	difference_type;
+      ///@}
+
+#if __cplusplus > 201402L
+      using node_type = typename _Hashtable::node_type;
+#endif
+
+      // construct/destroy/copy
+
+      /// Default constructor.
+      unordered_multiset() = default;
+
+      /**
+       *  @brief  Default constructor creates no elements.
+       *  @param __n  Minimal initial number of buckets.
+       *  @param __hf  A hash functor.
+       *  @param __eql  A key equality functor.
+       *  @param __a  An allocator object.
+       */
+      explicit
+      unordered_multiset(size_type __n,
+			 const hasher& __hf = hasher(),
+			 const key_equal& __eql = key_equal(),
+			 const allocator_type& __a = allocator_type())
+      : _M_h(__n, __hf, __eql, __a)
+      { }
+
+      /**
+       *  @brief  Builds an %unordered_multiset from a range.
+       *  @param  __first  An input iterator.
+       *  @param  __last   An input iterator.
+       *  @param __n       Minimal initial number of buckets.
+       *  @param __hf      A hash functor.
+       *  @param __eql     A key equality functor.
+       *  @param __a       An allocator object.
+       *
+       *  Create an %unordered_multiset consisting of copies of the elements
+       *  from [__first,__last).  This is linear in N (where N is
+       *  distance(__first,__last)).
+       */
+      template<typename _InputIterator>
+	unordered_multiset(_InputIterator __first, _InputIterator __last,
+			   size_type __n = 0,
+			   const hasher& __hf = hasher(),
+			   const key_equal& __eql = key_equal(),
+			   const allocator_type& __a = allocator_type())
+	: _M_h(__first, __last, __n, __hf, __eql, __a)
+	{ }
+
+      /// Copy constructor.
+      unordered_multiset(const unordered_multiset&) = default;
+
+      /// Move constructor.
+      unordered_multiset(unordered_multiset&&) = default;
+
+      /**
+       *  @brief  Builds an %unordered_multiset from an initializer_list.
+       *  @param  __l  An initializer_list.
+       *  @param __n  Minimal initial number of buckets.
+       *  @param __hf  A hash functor.
+       *  @param __eql  A key equality functor.
+       *  @param  __a  An allocator object.
+       *
+       *  Create an %unordered_multiset consisting of copies of the elements in
+       *  the list. This is linear in N (where N is @a __l.size()).
+       */
+      unordered_multiset(initializer_list<value_type> __l,
+			 size_type __n = 0,
+			 const hasher& __hf = hasher(),
+			 const key_equal& __eql = key_equal(),
+			 const allocator_type& __a = allocator_type())
+      : _M_h(__l, __n, __hf, __eql, __a)
+      { }
+
+      /// Copy assignment operator.
+      unordered_multiset&
+      operator=(const unordered_multiset&) = default;
+
+      /// Move assignment operator.
+      unordered_multiset&
+      operator=(unordered_multiset&&) = default;
+
+      /**
+       *  @brief Creates an %unordered_multiset with no elements.
+       *  @param __a An allocator object.
+       */
+      explicit
+      unordered_multiset(const allocator_type& __a)
+      : _M_h(__a)
+      { }
+
+      /*
+       *  @brief Copy constructor with allocator argument.
+       * @param  __uset  Input %unordered_multiset to copy.
+       * @param  __a  An allocator object.
+       */
+      unordered_multiset(const unordered_multiset& __umset,
+			 const allocator_type& __a)
+      : _M_h(__umset._M_h, __a)
+      { }
+
+      /*
+       *  @brief  Move constructor with allocator argument.
+       *  @param  __umset  Input %unordered_multiset to move.
+       *  @param  __a  An allocator object.
+       */
+      unordered_multiset(unordered_multiset&& __umset,
+			 const allocator_type& __a)
+	noexcept( noexcept(_Hashtable(std::move(__umset._M_h), __a)) )
+      : _M_h(std::move(__umset._M_h), __a)
+      { }
+
+      unordered_multiset(size_type __n, const allocator_type& __a)
+      : unordered_multiset(__n, hasher(), key_equal(), __a)
+      { }
+
+      unordered_multiset(size_type __n, const hasher& __hf,
+			 const allocator_type& __a)
+      : unordered_multiset(__n, __hf, key_equal(), __a)
+      { }
+
+      template<typename _InputIterator>
+	unordered_multiset(_InputIterator __first, _InputIterator __last,
+			   size_type __n,
+			   const allocator_type& __a)
+	: unordered_multiset(__first, __last, __n, hasher(), key_equal(), __a)
+	{ }
+
+      template<typename _InputIterator>
+	unordered_multiset(_InputIterator __first, _InputIterator __last,
+			   size_type __n, const hasher& __hf,
+			   const allocator_type& __a)
+	: unordered_multiset(__first, __last, __n, __hf, key_equal(), __a)
+	{ }
+
+      unordered_multiset(initializer_list<value_type> __l,
+			 size_type __n,
+			 const allocator_type& __a)
+      : unordered_multiset(__l, __n, hasher(), key_equal(), __a)
+      { }
+
+      unordered_multiset(initializer_list<value_type> __l,
+			 size_type __n, const hasher& __hf,
+			 const allocator_type& __a)
+      : unordered_multiset(__l, __n, __hf, key_equal(), __a)
+      { }
+
+      /**
+       *  @brief  %Unordered_multiset list assignment operator.
+       *  @param  __l  An initializer_list.
+       *
+       *  This function fills an %unordered_multiset with copies of the elements
+       *  in the initializer list @a __l.
+       *
+       *  Note that the assignment completely changes the %unordered_multiset
+       *  and that the resulting %unordered_multiset's size is the same as the
+       *  number of elements assigned.
+       */
+      unordered_multiset&
+      operator=(initializer_list<value_type> __l)
+      {
+	_M_h = __l;
+	return *this;
+      }
+
+      ///  Returns the allocator object used by the %unordered_multiset.
+      allocator_type
+      get_allocator() const noexcept
+      { return _M_h.get_allocator(); }
+
+      // size and capacity:
+
+      ///  Returns true if the %unordered_multiset is empty.
+      _GLIBCXX_NODISCARD bool
+      empty() const noexcept
+      { return _M_h.empty(); }
+
+      ///  Returns the size of the %unordered_multiset.
+      size_type
+      size() const noexcept
+      { return _M_h.size(); }
+
+      ///  Returns the maximum size of the %unordered_multiset.
+      size_type
+      max_size() const noexcept
+      { return _M_h.max_size(); }
+
+      // iterators.
+
+      ///@{
+      /**
+       *  Returns a read-only (constant) iterator that points to the first
+       *  element in the %unordered_multiset.
+       */
+      iterator
+      begin() noexcept
+      { return _M_h.begin(); }
+
+      const_iterator
+      begin() const noexcept
+      { return _M_h.begin(); }
+      ///@}
+
+      ///@{
+      /**
+       *  Returns a read-only (constant) iterator that points one past the last
+       *  element in the %unordered_multiset.
+       */
+      iterator
+      end() noexcept
+      { return _M_h.end(); }
+
+      const_iterator
+      end() const noexcept
+      { return _M_h.end(); }
+      ///@}
+
+      /**
+       *  Returns a read-only (constant) iterator that points to the first
+       *  element in the %unordered_multiset.
+       */
+      const_iterator
+      cbegin() const noexcept
+      { return _M_h.begin(); }
+
+      /**
+       *  Returns a read-only (constant) iterator that points one past the last
+       *  element in the %unordered_multiset.
+       */
+      const_iterator
+      cend() const noexcept
+      { return _M_h.end(); }
+
+      // modifiers.
+
+      /**
+       *  @brief Builds and insert an element into the %unordered_multiset.
+       *  @param __args  Arguments used to generate an element.
+       *  @return  An iterator that points to the inserted element.
+       *
+       *  Insertion requires amortized constant time.
+       */
+      template<typename... _Args>
+	iterator
+	emplace(_Args&&... __args)
+	{ return _M_h.emplace(std::forward<_Args>(__args)...); }
+
+      /**
+       *  @brief Inserts an element into the %unordered_multiset.
+       *  @param  __pos  An iterator that serves as a hint as to where the
+       *                element should be inserted.
+       *  @param  __args  Arguments used to generate the element to be
+       *                 inserted.
+       *  @return An iterator that points to the inserted element.
+       *
+       *  Note that the first parameter is only a hint and can potentially
+       *  improve the performance of the insertion process.  A bad hint would
+       *  cause no gains in efficiency.
+       *
+       *  For more on @a hinting, see:
+       *  https://gcc.gnu.org/onlinedocs/libstdc++/manual/associative.html#containers.associative.insert_hints
+       *
+       *  Insertion requires amortized constant time.
+       */
+      template<typename... _Args>
+	iterator
+	emplace_hint(const_iterator __pos, _Args&&... __args)
+	{ return _M_h.emplace_hint(__pos, std::forward<_Args>(__args)...); }
+
+      ///@{
+      /**
+       *  @brief Inserts an element into the %unordered_multiset.
+       *  @param  __x  Element to be inserted.
+       *  @return  An iterator that points to the inserted element.
+       *
+       *  Insertion requires amortized constant time.
+       */
+      iterator
+      insert(const value_type& __x)
+      { return _M_h.insert(__x); }
+
+      iterator
+      insert(value_type&& __x)
+      { return _M_h.insert(std::move(__x)); }
+      ///@}
+
+      ///@{
+      /**
+       *  @brief Inserts an element into the %unordered_multiset.
+       *  @param  __hint  An iterator that serves as a hint as to where the
+       *                 element should be inserted.
+       *  @param  __x  Element to be inserted.
+       *  @return An iterator that points to the inserted element.
+       *
+       *  Note that the first parameter is only a hint and can potentially
+       *  improve the performance of the insertion process.  A bad hint would
+       *  cause no gains in efficiency.
+       *
+       *  For more on @a hinting, see:
+       *  https://gcc.gnu.org/onlinedocs/libstdc++/manual/associative.html#containers.associative.insert_hints
+       *
+       *  Insertion requires amortized constant.
+       */
+      iterator
+      insert(const_iterator __hint, const value_type& __x)
+      { return _M_h.insert(__hint, __x); }
+
+      iterator
+      insert(const_iterator __hint, value_type&& __x)
+      { return _M_h.insert(__hint, std::move(__x)); }
+      ///@}
+
+      /**
+       *  @brief A template function that inserts a range of elements.
+       *  @param  __first  Iterator pointing to the start of the range to be
+       *                   inserted.
+       *  @param  __last  Iterator pointing to the end of the range.
+       *
+       *  Complexity similar to that of the range constructor.
+       */
+      template<typename _InputIterator>
+	void
+	insert(_InputIterator __first, _InputIterator __last)
+	{ _M_h.insert(__first, __last); }
+
+      /**
+       *  @brief Inserts a list of elements into the %unordered_multiset.
+       *  @param  __l  A std::initializer_list<value_type> of elements to be
+       *              inserted.
+       *
+       *  Complexity similar to that of the range constructor.
+       */
+      void
+      insert(initializer_list<value_type> __l)
+      { _M_h.insert(__l); }
+
+#if __cplusplus > 201402L
+      /// Extract a node.
+      node_type
+      extract(const_iterator __pos)
+      {
+	__glibcxx_assert(__pos != end());
+	return _M_h.extract(__pos);
+      }
+
+      /// Extract a node.
+      node_type
+      extract(const key_type& __key)
+      { return _M_h.extract(__key); }
+
+      /// Re-insert an extracted node.
+      iterator
+      insert(node_type&& __nh)
+      { return _M_h._M_reinsert_node_multi(cend(), std::move(__nh)); }
+
+      /// Re-insert an extracted node.
+      iterator
+      insert(const_iterator __hint, node_type&& __nh)
+      { return _M_h._M_reinsert_node_multi(__hint, std::move(__nh)); }
+#endif // C++17
+
+      ///@{
+      /**
+       *  @brief Erases an element from an %unordered_multiset.
+       *  @param  __position  An iterator pointing to the element to be erased.
+       *  @return An iterator pointing to the element immediately following
+       *          @a __position prior to the element being erased. If no such
+       *          element exists, end() is returned.
+       *
+       *  This function erases an element, pointed to by the given iterator,
+       *  from an %unordered_multiset.
+       *
+       *  Note that this function only erases the element, and that if the
+       *  element is itself a pointer, the pointed-to memory is not touched in
+       *  any way.  Managing the pointer is the user's responsibility.
+       */
+      iterator
+      erase(const_iterator __position)
+      { return _M_h.erase(__position); }
+
+      // LWG 2059.
+      iterator
+      erase(iterator __position)
+      { return _M_h.erase(__position); }
+      ///@}
+
+
+      /**
+       *  @brief Erases elements according to the provided key.
+       *  @param  __x  Key of element to be erased.
+       *  @return  The number of elements erased.
+       *
+       *  This function erases all the elements located by the given key from
+       *  an %unordered_multiset.
+       *
+       *  Note that this function only erases the element, and that if the
+       *  element is itself a pointer, the pointed-to memory is not touched in
+       *  any way.  Managing the pointer is the user's responsibility.
+       */
+      size_type
+      erase(const key_type& __x)
+      { return _M_h.erase(__x); }
+
+      /**
+       *  @brief Erases a [__first,__last) range of elements from an
+       *  %unordered_multiset.
+       *  @param  __first  Iterator pointing to the start of the range to be
+       *                  erased.
+       *  @param __last  Iterator pointing to the end of the range to
+       *                be erased.
+       *  @return The iterator @a __last.
+       *
+       *  This function erases a sequence of elements from an
+       *  %unordered_multiset.
+       *
+       *  Note that this function only erases the element, and that if
+       *  the element is itself a pointer, the pointed-to memory is not touched
+       *  in any way.  Managing the pointer is the user's responsibility.
+       */
+      iterator
+      erase(const_iterator __first, const_iterator __last)
+      { return _M_h.erase(__first, __last); }
+
+      /**
+       *  Erases all elements in an %unordered_multiset.
+       *
+       *  Note that this function only erases the elements, and that if the
+       *  elements themselves are pointers, the pointed-to memory is not touched
+       *  in any way. Managing the pointer is the user's responsibility.
+       */
+      void
+      clear() noexcept
+      { _M_h.clear(); }
+
+      /**
+       *  @brief  Swaps data with another %unordered_multiset.
+       *  @param  __x  An %unordered_multiset of the same element and allocator
+       *  types.
+       *
+       *  This exchanges the elements between two sets in constant time.
+       *  Note that the global std::swap() function is specialized such that
+       *  std::swap(s1,s2) will feed to this function.
+       */
+      void
+      swap(unordered_multiset& __x)
+      noexcept( noexcept(_M_h.swap(__x._M_h)) )
+      { _M_h.swap(__x._M_h); }
+
+#if __cplusplus > 201402L
+      template<typename, typename, typename>
+	friend class std::_Hash_merge_helper;
+
+      template<typename _H2, typename _P2>
+	void
+	merge(unordered_multiset<_Value, _H2, _P2, _Alloc>& __source)
+	{
+	  using _Merge_helper
+	    = _Hash_merge_helper<unordered_multiset, _H2, _P2>;
+	  _M_h._M_merge_multi(_Merge_helper::_S_get_table(__source));
+	}
+
+      template<typename _H2, typename _P2>
+	void
+	merge(unordered_multiset<_Value, _H2, _P2, _Alloc>&& __source)
+	{ merge(__source); }
+
+      template<typename _H2, typename _P2>
+	void
+	merge(unordered_set<_Value, _H2, _P2, _Alloc>& __source)
+	{
+	  using _Merge_helper
+	    = _Hash_merge_helper<unordered_multiset, _H2, _P2>;
+	  _M_h._M_merge_multi(_Merge_helper::_S_get_table(__source));
+	}
+
+      template<typename _H2, typename _P2>
+	void
+	merge(unordered_set<_Value, _H2, _P2, _Alloc>&& __source)
+	{ merge(__source); }
+#endif // C++17
+
+      // observers.
+
+      ///  Returns the hash functor object with which the %unordered_multiset
+      ///  was constructed.
+      hasher
+      hash_function() const
+      { return _M_h.hash_function(); }
+
+      ///  Returns the key comparison object with which the %unordered_multiset
+      ///  was constructed.
+      key_equal
+      key_eq() const
+      { return _M_h.key_eq(); }
+
+      // lookup.
+
+      ///@{
+      /**
+       *  @brief Tries to locate an element in an %unordered_multiset.
+       *  @param  __x  Element to be located.
+       *  @return  Iterator pointing to sought-after element, or end() if not
+       *           found.
+       *
+       *  This function takes a key and tries to locate the element with which
+       *  the key matches.  If successful the function returns an iterator
+       *  pointing to the sought after element.  If unsuccessful it returns the
+       *  past-the-end ( @c end() ) iterator.
+       */
+      iterator
+      find(const key_type& __x)
+      { return _M_h.find(__x); }
+
+#if __cplusplus > 201703L
+      template<typename _Kt>
+	auto
+	find(const _Kt& __x)
+	-> decltype(_M_h._M_find_tr(__x))
+	{ return _M_h._M_find_tr(__x); }
+#endif
+
+      const_iterator
+      find(const key_type& __x) const
+      { return _M_h.find(__x); }
+
+#if __cplusplus > 201703L
+      template<typename _Kt>
+	auto
+	find(const _Kt& __x) const
+	-> decltype(_M_h._M_find_tr(__x))
+	{ return _M_h._M_find_tr(__x); }
+#endif
+      ///@}
+
+      ///@{
+      /**
+       *  @brief  Finds the number of elements.
+       *  @param  __x  Element to located.
+       *  @return  Number of elements with specified key.
+       */
+      size_type
+      count(const key_type& __x) const
+      { return _M_h.count(__x); }
+
+#if __cplusplus > 201703L
+      template<typename _Kt>
+	auto
+	count(const _Kt& __x) const -> decltype(_M_h._M_count_tr(__x))
+	{ return _M_h._M_count_tr(__x); }
+#endif
+      ///@}
+
+#if __cplusplus > 201703L
+      ///@{
+      /**
+       *  @brief  Finds whether an element with the given key exists.
+       *  @param  __x  Key of elements to be located.
+       *  @return  True if there is any element with the specified key.
+       */
+      bool
+      contains(const key_type& __x) const
+      { return _M_h.find(__x) != _M_h.end(); }
+
+      template<typename _Kt>
+	auto
+	contains(const _Kt& __x) const
+	-> decltype(_M_h._M_find_tr(__x), void(), true)
+	{ return _M_h._M_find_tr(__x) != _M_h.end(); }
+      ///@}
+#endif
+
+      ///@{
+      /**
+       *  @brief Finds a subsequence matching given key.
+       *  @param  __x  Key to be located.
+       *  @return  Pair of iterators that possibly points to the subsequence
+       *           matching given key.
+       */
+      std::pair<iterator, iterator>
+      equal_range(const key_type& __x)
+      { return _M_h.equal_range(__x); }
+
+#if __cplusplus > 201703L
+      template<typename _Kt>
+	auto
+	equal_range(const _Kt& __x)
+	-> decltype(_M_h._M_equal_range_tr(__x))
+	{ return _M_h._M_equal_range_tr(__x); }
+#endif
+
+      std::pair<const_iterator, const_iterator>
+      equal_range(const key_type& __x) const
+      { return _M_h.equal_range(__x); }
+
+#if __cplusplus > 201703L
+      template<typename _Kt>
+	auto
+	equal_range(const _Kt& __x) const
+	-> decltype(_M_h._M_equal_range_tr(__x))
+	{ return _M_h._M_equal_range_tr(__x); }
+#endif
+      ///@}
+
+      // bucket interface.
+
+      /// Returns the number of buckets of the %unordered_multiset.
+      size_type
+      bucket_count() const noexcept
+      { return _M_h.bucket_count(); }
+
+      /// Returns the maximum number of buckets of the %unordered_multiset.
+      size_type
+      max_bucket_count() const noexcept
+      { return _M_h.max_bucket_count(); }
+
+      /*
+       * @brief  Returns the number of elements in a given bucket.
+       * @param  __n  A bucket index.
+       * @return  The number of elements in the bucket.
+       */
+      size_type
+      bucket_size(size_type __n) const
+      { return _M_h.bucket_size(__n); }
+
+      /*
+       * @brief  Returns the bucket index of a given element.
+       * @param  __key  A key instance.
+       * @return  The key bucket index.
+       */
+      size_type
+      bucket(const key_type& __key) const
+      { return _M_h.bucket(__key); }
+
+      ///@{
+      /**
+       *  @brief  Returns a read-only (constant) iterator pointing to the first
+       *         bucket element.
+       *  @param  __n The bucket index.
+       *  @return  A read-only local iterator.
+       */
+      local_iterator
+      begin(size_type __n)
+      { return _M_h.begin(__n); }
+
+      const_local_iterator
+      begin(size_type __n) const
+      { return _M_h.begin(__n); }
+
+      const_local_iterator
+      cbegin(size_type __n) const
+      { return _M_h.cbegin(__n); }
+      ///@}
+
+      ///@{
+      /**
+       *  @brief  Returns a read-only (constant) iterator pointing to one past
+       *         the last bucket elements.
+       *  @param  __n The bucket index.
+       *  @return  A read-only local iterator.
+       */
+      local_iterator
+      end(size_type __n)
+      { return _M_h.end(__n); }
+
+      const_local_iterator
+      end(size_type __n) const
+      { return _M_h.end(__n); }
+
+      const_local_iterator
+      cend(size_type __n) const
+      { return _M_h.cend(__n); }
+      ///@}
+
+      // hash policy.
+
+      /// Returns the average number of elements per bucket.
+      float
+      load_factor() const noexcept
+      { return _M_h.load_factor(); }
+
+      /// Returns a positive number that the %unordered_multiset tries to keep the
+      /// load factor less than or equal to.
+      float
+      max_load_factor() const noexcept
+      { return _M_h.max_load_factor(); }
+
+      /**
+       *  @brief  Change the %unordered_multiset maximum load factor.
+       *  @param  __z The new maximum load factor.
+       */
+      void
+      max_load_factor(float __z)
+      { _M_h.max_load_factor(__z); }
+
+      /**
+       *  @brief  May rehash the %unordered_multiset.
+       *  @param  __n The new number of buckets.
+       *
+       *  Rehash will occur only if the new number of buckets respect the
+       *  %unordered_multiset maximum load factor.
+       */
+      void
+      rehash(size_type __n)
+      { _M_h.rehash(__n); }
+
+      /**
+       *  @brief  Prepare the %unordered_multiset for a specified number of
+       *          elements.
+       *  @param  __n Number of elements required.
+       *
+       *  Same as rehash(ceil(n / max_load_factor())).
+       */
+      void
+      reserve(size_type __n)
+      { _M_h.reserve(__n); }
+
+      template<typename _Value1, typename _Hash1, typename _Pred1,
+	       typename _Alloc1>
+        friend bool
+      operator==(const unordered_multiset<_Value1, _Hash1, _Pred1, _Alloc1>&,
+		 const unordered_multiset<_Value1, _Hash1, _Pred1, _Alloc1>&);
+    };
+
+
+#if __cpp_deduction_guides >= 201606
+
+  template<typename _InputIterator,
+	   typename _Hash =
+	     hash<typename iterator_traits<_InputIterator>::value_type>,
+	   typename _Pred =
+	     equal_to<typename iterator_traits<_InputIterator>::value_type>,
+	   typename _Allocator =
+	     allocator<typename iterator_traits<_InputIterator>::value_type>,
+	   typename = _RequireInputIter<_InputIterator>,
+	   typename = _RequireNotAllocatorOrIntegral<_Hash>,
+	   typename = _RequireNotAllocator<_Pred>,
+	   typename = _RequireAllocator<_Allocator>>
+    unordered_multiset(_InputIterator, _InputIterator,
+		       unordered_multiset<int>::size_type = {},
+		       _Hash = _Hash(), _Pred = _Pred(),
+		       _Allocator = _Allocator())
+    -> unordered_multiset<typename iterator_traits<_InputIterator>::value_type,
+                          _Hash, _Pred, _Allocator>;
+
+  template<typename _Tp, typename _Hash = hash<_Tp>,
+	   typename _Pred = equal_to<_Tp>,
+	   typename _Allocator = allocator<_Tp>,
+	   typename = _RequireNotAllocatorOrIntegral<_Hash>,
+	   typename = _RequireNotAllocator<_Pred>,
+	   typename = _RequireAllocator<_Allocator>>
+    unordered_multiset(initializer_list<_Tp>,
+		       unordered_multiset<int>::size_type = {},
+		       _Hash = _Hash(), _Pred = _Pred(),
+		       _Allocator = _Allocator())
+    -> unordered_multiset<_Tp, _Hash, _Pred, _Allocator>;
+
+  template<typename _InputIterator, typename _Allocator,
+	   typename = _RequireInputIter<_InputIterator>,
+	   typename = _RequireAllocator<_Allocator>>
+    unordered_multiset(_InputIterator, _InputIterator,
+		       unordered_multiset<int>::size_type, _Allocator)
+    -> unordered_multiset<typename iterator_traits<_InputIterator>::value_type,
+			  hash<typename
+			       iterator_traits<_InputIterator>::value_type>,
+			  equal_to<typename
+				   iterator_traits<_InputIterator>::value_type>,
+			  _Allocator>;
+
+  template<typename _InputIterator, typename _Hash, typename _Allocator,
+	   typename = _RequireInputIter<_InputIterator>,
+	   typename = _RequireNotAllocatorOrIntegral<_Hash>,
+	   typename = _RequireAllocator<_Allocator>>
+    unordered_multiset(_InputIterator, _InputIterator,
+		       unordered_multiset<int>::size_type,
+		       _Hash, _Allocator)
+    -> unordered_multiset<typename
+			  iterator_traits<_InputIterator>::value_type,
+			  _Hash,
+			  equal_to<
+			    typename
+			    iterator_traits<_InputIterator>::value_type>,
+			  _Allocator>;
+
+  template<typename _Tp, typename _Allocator,
+	   typename = _RequireAllocator<_Allocator>>
+    unordered_multiset(initializer_list<_Tp>,
+		       unordered_multiset<int>::size_type, _Allocator)
+    -> unordered_multiset<_Tp, hash<_Tp>, equal_to<_Tp>, _Allocator>;
+
+  template<typename _Tp, typename _Hash, typename _Allocator,
+	   typename = _RequireNotAllocatorOrIntegral<_Hash>,
+	   typename = _RequireAllocator<_Allocator>>
+    unordered_multiset(initializer_list<_Tp>,
+		       unordered_multiset<int>::size_type, _Hash, _Allocator)
+    -> unordered_multiset<_Tp, _Hash, equal_to<_Tp>, _Allocator>;
+
+#endif
+
+  template<class _Value, class _Hash, class _Pred, class _Alloc>
+    inline void
+    swap(unordered_set<_Value, _Hash, _Pred, _Alloc>& __x,
+	 unordered_set<_Value, _Hash, _Pred, _Alloc>& __y)
+    noexcept(noexcept(__x.swap(__y)))
+    { __x.swap(__y); }
+
+  template<class _Value, class _Hash, class _Pred, class _Alloc>
+    inline void
+    swap(unordered_multiset<_Value, _Hash, _Pred, _Alloc>& __x,
+	 unordered_multiset<_Value, _Hash, _Pred, _Alloc>& __y)
+    noexcept(noexcept(__x.swap(__y)))
+    { __x.swap(__y); }
+
+  template<class _Value, class _Hash, class _Pred, class _Alloc>
+    inline bool
+    operator==(const unordered_set<_Value, _Hash, _Pred, _Alloc>& __x,
+	       const unordered_set<_Value, _Hash, _Pred, _Alloc>& __y)
+    { return __x._M_h._M_equal(__y._M_h); }
+
+#if __cpp_impl_three_way_comparison < 201907L
+  template<class _Value, class _Hash, class _Pred, class _Alloc>
+    inline bool
+    operator!=(const unordered_set<_Value, _Hash, _Pred, _Alloc>& __x,
+	       const unordered_set<_Value, _Hash, _Pred, _Alloc>& __y)
+    { return !(__x == __y); }
+#endif
+
+  template<class _Value, class _Hash, class _Pred, class _Alloc>
+    inline bool
+    operator==(const unordered_multiset<_Value, _Hash, _Pred, _Alloc>& __x,
+	       const unordered_multiset<_Value, _Hash, _Pred, _Alloc>& __y)
+    { return __x._M_h._M_equal(__y._M_h); }
+
+#if __cpp_impl_three_way_comparison < 201907L
+  template<class _Value, class _Hash, class _Pred, class _Alloc>
+    inline bool
+    operator!=(const unordered_multiset<_Value, _Hash, _Pred, _Alloc>& __x,
+	       const unordered_multiset<_Value, _Hash, _Pred, _Alloc>& __y)
+    { return !(__x == __y); }
+#endif
+
+_GLIBCXX_END_NAMESPACE_CONTAINER
+
+#if __cplusplus > 201402L
+  // Allow std::unordered_set access to internals of compatible sets.
+  template<typename _Val, typename _Hash1, typename _Eq1, typename _Alloc,
+	   typename _Hash2, typename _Eq2>
+    struct _Hash_merge_helper<
+      _GLIBCXX_STD_C::unordered_set<_Val, _Hash1, _Eq1, _Alloc>, _Hash2, _Eq2>
+    {
+    private:
+      template<typename... _Tp>
+	using unordered_set = _GLIBCXX_STD_C::unordered_set<_Tp...>;
+      template<typename... _Tp>
+	using unordered_multiset = _GLIBCXX_STD_C::unordered_multiset<_Tp...>;
+
+      friend unordered_set<_Val, _Hash1, _Eq1, _Alloc>;
+
+      static auto&
+      _S_get_table(unordered_set<_Val, _Hash2, _Eq2, _Alloc>& __set)
+      { return __set._M_h; }
+
+      static auto&
+      _S_get_table(unordered_multiset<_Val, _Hash2, _Eq2, _Alloc>& __set)
+      { return __set._M_h; }
+    };
+
+  // Allow std::unordered_multiset access to internals of compatible sets.
+  template<typename _Val, typename _Hash1, typename _Eq1, typename _Alloc,
+	   typename _Hash2, typename _Eq2>
+    struct _Hash_merge_helper<
+      _GLIBCXX_STD_C::unordered_multiset<_Val, _Hash1, _Eq1, _Alloc>,
+      _Hash2, _Eq2>
+    {
+    private:
+      template<typename... _Tp>
+	using unordered_set = _GLIBCXX_STD_C::unordered_set<_Tp...>;
+      template<typename... _Tp>
+	using unordered_multiset = _GLIBCXX_STD_C::unordered_multiset<_Tp...>;
+
+      friend unordered_multiset<_Val, _Hash1, _Eq1, _Alloc>;
+
+      static auto&
+      _S_get_table(unordered_set<_Val, _Hash2, _Eq2, _Alloc>& __set)
+      { return __set._M_h; }
+
+      static auto&
+      _S_get_table(unordered_multiset<_Val, _Hash2, _Eq2, _Alloc>& __set)
+      { return __set._M_h; }
+    };
+#endif // C++17
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif /* _UNORDERED_SET_H */
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@uses_allocator.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@uses_allocator.h
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@uses_allocator.h
@@ -0,0 +1,197 @@
+// Uses-allocator Construction -*- C++ -*-
+
+// Copyright (C) 2010-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+#ifndef _USES_ALLOCATOR_H
+#define _USES_ALLOCATOR_H 1
+
+#if __cplusplus < 201103L
+# include <bits/c++0x_warning.h>
+#else
+
+#include <type_traits>
+#include <bits/move.h>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+/// @cond undocumented
+
+  // This is used for std::experimental::erased_type from Library Fundamentals.
+  struct __erased_type { };
+
+  // This also supports the "type-erased allocator" protocol from the
+  // Library Fundamentals TS, where allocator_type is erased_type.
+  // The second condition will always be false for types not using the TS.
+  template<typename _Alloc, typename _Tp>
+    using __is_erased_or_convertible
+      = __or_<is_convertible<_Alloc, _Tp>, is_same<_Tp, __erased_type>>;
+
+  /// [allocator.tag]
+  struct allocator_arg_t { explicit allocator_arg_t() = default; };
+
+  _GLIBCXX17_INLINE constexpr allocator_arg_t allocator_arg =
+    allocator_arg_t();
+
+  template<typename _Tp, typename _Alloc, typename = __void_t<>>
+    struct __uses_allocator_helper
+    : false_type { };
+
+  template<typename _Tp, typename _Alloc>
+    struct __uses_allocator_helper<_Tp, _Alloc,
+				   __void_t<typename _Tp::allocator_type>>
+    : __is_erased_or_convertible<_Alloc, typename _Tp::allocator_type>::type
+    { };
+
+  /// [allocator.uses.trait]
+  template<typename _Tp, typename _Alloc>
+    struct uses_allocator
+    : __uses_allocator_helper<_Tp, _Alloc>::type
+    { };
+
+  struct __uses_alloc_base { };
+
+  struct __uses_alloc0 : __uses_alloc_base
+  {
+    struct _Sink { void _GLIBCXX20_CONSTEXPR operator=(const void*) { } } _M_a;
+  };
+
+  template<typename _Alloc>
+    struct __uses_alloc1 : __uses_alloc_base { const _Alloc* _M_a; };
+
+  template<typename _Alloc>
+    struct __uses_alloc2 : __uses_alloc_base { const _Alloc* _M_a; };
+
+  template<bool, typename _Tp, typename _Alloc, typename... _Args>
+    struct __uses_alloc;
+
+  template<typename _Tp, typename _Alloc, typename... _Args>
+    struct __uses_alloc<true, _Tp, _Alloc, _Args...>
+    : __conditional_t<
+        is_constructible<_Tp, allocator_arg_t, const _Alloc&, _Args...>::value,
+        __uses_alloc1<_Alloc>,
+       	__uses_alloc2<_Alloc>>
+    {
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 2586. Wrong value category used in scoped_allocator_adaptor::construct
+      static_assert(__or_<
+	  is_constructible<_Tp, allocator_arg_t, const _Alloc&, _Args...>,
+	  is_constructible<_Tp, _Args..., const _Alloc&>>::value,
+	  "construction with an allocator must be possible"
+	  " if uses_allocator is true");
+    };
+
+  template<typename _Tp, typename _Alloc, typename... _Args>
+    struct __uses_alloc<false, _Tp, _Alloc, _Args...>
+    : __uses_alloc0 { };
+
+  template<typename _Tp, typename _Alloc, typename... _Args>
+    using __uses_alloc_t =
+      __uses_alloc<uses_allocator<_Tp, _Alloc>::value, _Tp, _Alloc, _Args...>;
+
+  template<typename _Tp, typename _Alloc, typename... _Args>
+    _GLIBCXX20_CONSTEXPR
+    inline __uses_alloc_t<_Tp, _Alloc, _Args...>
+    __use_alloc(const _Alloc& __a)
+    {
+      __uses_alloc_t<_Tp, _Alloc, _Args...> __ret;
+      __ret._M_a = std::__addressof(__a);
+      return __ret;
+    }
+
+  template<typename _Tp, typename _Alloc, typename... _Args>
+    void
+    __use_alloc(const _Alloc&&) = delete;
+
+#if __cplusplus > 201402L
+  template <typename _Tp, typename _Alloc>
+    inline constexpr bool uses_allocator_v =
+      uses_allocator<_Tp, _Alloc>::value;
+#endif // C++17
+
+  template<template<typename...> class _Predicate,
+	   typename _Tp, typename _Alloc, typename... _Args>
+    struct __is_uses_allocator_predicate
+    : __conditional_t<uses_allocator<_Tp, _Alloc>::value,
+      __or_<_Predicate<_Tp, allocator_arg_t, _Alloc, _Args...>,
+	    _Predicate<_Tp, _Args..., _Alloc>>,
+      _Predicate<_Tp, _Args...>> { };
+
+  template<typename _Tp, typename _Alloc, typename... _Args>
+    struct __is_uses_allocator_constructible
+    : __is_uses_allocator_predicate<is_constructible, _Tp, _Alloc, _Args...>
+    { };
+
+#if __cplusplus >= 201402L
+  template<typename _Tp, typename _Alloc, typename... _Args>
+    _GLIBCXX17_INLINE constexpr bool __is_uses_allocator_constructible_v =
+      __is_uses_allocator_constructible<_Tp, _Alloc, _Args...>::value;
+#endif // C++14
+
+  template<typename _Tp, typename _Alloc, typename... _Args>
+    struct __is_nothrow_uses_allocator_constructible
+    : __is_uses_allocator_predicate<is_nothrow_constructible,
+				    _Tp, _Alloc, _Args...>
+    { };
+
+
+#if __cplusplus >= 201402L
+  template<typename _Tp, typename _Alloc, typename... _Args>
+    _GLIBCXX17_INLINE constexpr bool
+    __is_nothrow_uses_allocator_constructible_v =
+      __is_nothrow_uses_allocator_constructible<_Tp, _Alloc, _Args...>::value;
+#endif // C++14
+
+  template<typename _Tp, typename... _Args>
+    void __uses_allocator_construct_impl(__uses_alloc0 __a, _Tp* __ptr,
+					 _Args&&... __args)
+    { ::new ((void*)__ptr) _Tp(std::forward<_Args>(__args)...); }
+
+  template<typename _Tp, typename _Alloc, typename... _Args>
+    void __uses_allocator_construct_impl(__uses_alloc1<_Alloc> __a, _Tp* __ptr,
+					 _Args&&... __args)
+    {
+      ::new ((void*)__ptr) _Tp(allocator_arg, *__a._M_a,
+			       std::forward<_Args>(__args)...);
+    }
+
+  template<typename _Tp, typename _Alloc, typename... _Args>
+    void __uses_allocator_construct_impl(__uses_alloc2<_Alloc> __a, _Tp* __ptr,
+					 _Args&&... __args)
+    { ::new ((void*)__ptr) _Tp(std::forward<_Args>(__args)..., *__a._M_a); }
+
+  template<typename _Tp, typename _Alloc, typename... _Args>
+    void __uses_allocator_construct(const _Alloc& __a, _Tp* __ptr,
+				    _Args&&... __args)
+    {
+      std::__uses_allocator_construct_impl(
+	  std::__use_alloc<_Tp, _Alloc, _Args...>(__a), __ptr,
+	  std::forward<_Args>(__args)...);
+    }
+
+/// @endcond
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif
+#endif
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@utility.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@utility.h
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@utility.h
@@ -0,0 +1,270 @@
+// Utilities used throughout the library -*- C++ -*-
+
+// Copyright (C) 2004-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file include/bits/utility.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{utility}
+ *
+ *  This file contains the parts of `<utility>` needed by other headers,
+ *  so they don't need to include the whole of `<utility>`.
+ */
+
+#ifndef _GLIBCXX_UTILITY_H
+#define _GLIBCXX_UTILITY_H 1
+
+#pragma GCC system_header
+
+#if __cplusplus >= 201103L
+
+#include <type_traits>
+#include <bits/move.h>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /// Finds the size of a given tuple type.
+  template<typename _Tp>
+    struct tuple_size;
+
+  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+  // 2313. tuple_size should always derive from integral_constant<size_t, N>
+  // 2770. tuple_size<const T> specialization is not SFINAE compatible
+
+  template<typename _Tp,
+	   typename _Up = typename remove_cv<_Tp>::type,
+	   typename = typename enable_if<is_same<_Tp, _Up>::value>::type,
+	   size_t = tuple_size<_Tp>::value>
+    using __enable_if_has_tuple_size = _Tp;
+
+  template<typename _Tp>
+    struct tuple_size<const __enable_if_has_tuple_size<_Tp>>
+    : public tuple_size<_Tp> { };
+
+  template<typename _Tp>
+    struct tuple_size<volatile __enable_if_has_tuple_size<_Tp>>
+    : public tuple_size<_Tp> { };
+
+  template<typename _Tp>
+    struct tuple_size<const volatile __enable_if_has_tuple_size<_Tp>>
+    : public tuple_size<_Tp> { };
+
+#if __cplusplus >= 201703L
+  template<typename _Tp>
+    inline constexpr size_t tuple_size_v = tuple_size<_Tp>::value;
+#endif
+
+  /// Gives the type of the ith element of a given tuple type.
+  template<size_t __i, typename _Tp>
+    struct tuple_element;
+
+  // Duplicate of C++14's tuple_element_t for internal use in C++11 mode
+  template<size_t __i, typename _Tp>
+    using __tuple_element_t = typename tuple_element<__i, _Tp>::type;
+
+  template<size_t __i, typename _Tp>
+    struct tuple_element<__i, const _Tp>
+    {
+      typedef typename add_const<__tuple_element_t<__i, _Tp>>::type type;
+    };
+
+  template<size_t __i, typename _Tp>
+    struct tuple_element<__i, volatile _Tp>
+    {
+      typedef typename add_volatile<__tuple_element_t<__i, _Tp>>::type type;
+    };
+
+  template<size_t __i, typename _Tp>
+    struct tuple_element<__i, const volatile _Tp>
+    {
+      typedef typename add_cv<__tuple_element_t<__i, _Tp>>::type type;
+    };
+
+#if __cplusplus >= 201402L
+
+  // Return the index of _Tp in _Types, if it occurs exactly once.
+  // Otherwise, return sizeof...(_Types).
+  template<typename _Tp, typename... _Types>
+    constexpr size_t
+    __find_uniq_type_in_pack()
+    {
+      constexpr size_t __sz = sizeof...(_Types);
+      constexpr bool __found[__sz] = { __is_same(_Tp, _Types) ... };
+      size_t __n = __sz;
+      for (size_t __i = 0; __i < __sz; ++__i)
+	{
+	  if (__found[__i])
+	    {
+	      if (__n < __sz) // more than one _Tp found
+		return __sz;
+	      __n = __i;
+	    }
+	}
+      return __n;
+    }
+
+// The standard says this macro and alias template should be in <tuple> but we
+// define them here, to be available in <array>, <utility> and <ranges> too.
+// _GLIBCXX_RESOLVE_LIB_DEFECTS
+// 3378. tuple_size_v/tuple_element_t should be available when
+//       tuple_size/tuple_element are
+#define __cpp_lib_tuple_element_t 201402L
+
+  template<size_t __i, typename _Tp>
+    using tuple_element_t = typename tuple_element<__i, _Tp>::type;
+#endif // C++14
+
+  // Stores a tuple of indices.  Used by tuple and pair, and by bind() to
+  // extract the elements in a tuple.
+  template<size_t... _Indexes> struct _Index_tuple { };
+
+  // Builds an _Index_tuple<0, 1, 2, ..., _Num-1>.
+  template<size_t _Num>
+    struct _Build_index_tuple
+    {
+#if __has_builtin(__make_integer_seq)
+      template<typename, size_t... _Indices>
+	using _IdxTuple = _Index_tuple<_Indices...>;
+
+      // Clang defines __make_integer_seq for this purpose.
+      using __type = __make_integer_seq<_IdxTuple, size_t, _Num>;
+#else
+      // For GCC and other compilers, use __integer_pack instead.
+      using __type = _Index_tuple<__integer_pack(_Num)...>;
+#endif
+    };
+
+#if __cplusplus >= 201402L
+
+#define __cpp_lib_integer_sequence 201304L
+
+  /// Class template integer_sequence
+  template<typename _Tp, _Tp... _Idx>
+    struct integer_sequence
+    {
+      typedef _Tp value_type;
+      static constexpr size_t size() noexcept { return sizeof...(_Idx); }
+    };
+
+  /// Alias template make_integer_sequence
+  template<typename _Tp, _Tp _Num>
+    using make_integer_sequence
+#if __has_builtin(__make_integer_seq)
+      = __make_integer_seq<integer_sequence, _Tp, _Num>;
+#else
+      = integer_sequence<_Tp, __integer_pack(_Num)...>;
+#endif
+
+  /// Alias template index_sequence
+  template<size_t... _Idx>
+    using index_sequence = integer_sequence<size_t, _Idx...>;
+
+  /// Alias template make_index_sequence
+  template<size_t _Num>
+    using make_index_sequence = make_integer_sequence<size_t, _Num>;
+
+  /// Alias template index_sequence_for
+  template<typename... _Types>
+    using index_sequence_for = make_index_sequence<sizeof...(_Types)>;
+
+#if __cplusplus >= 201703L
+
+  struct in_place_t {
+    explicit in_place_t() = default;
+  };
+
+  inline constexpr in_place_t in_place{};
+
+  template<typename _Tp> struct in_place_type_t
+  {
+    explicit in_place_type_t() = default;
+  };
+
+  template<typename _Tp>
+    inline constexpr in_place_type_t<_Tp> in_place_type{};
+
+  template<size_t _Idx> struct in_place_index_t
+  {
+    explicit in_place_index_t() = default;
+  };
+
+  template<size_t _Idx>
+    inline constexpr in_place_index_t<_Idx> in_place_index{};
+
+  template<typename>
+    inline constexpr bool __is_in_place_type_v = false;
+
+  template<typename _Tp>
+    inline constexpr bool __is_in_place_type_v<in_place_type_t<_Tp>> = true;
+
+  template<typename _Tp>
+    using __is_in_place_type = bool_constant<__is_in_place_type_v<_Tp>>;
+
+#endif // C++17
+#endif // C++14
+
+  template<size_t _Np, typename... _Types>
+    struct _Nth_type
+    { };
+
+  template<typename _Tp0, typename... _Rest>
+    struct _Nth_type<0, _Tp0, _Rest...>
+    { using type = _Tp0; };
+
+  template<typename _Tp0, typename _Tp1, typename... _Rest>
+    struct _Nth_type<1, _Tp0, _Tp1, _Rest...>
+    { using type = _Tp1; };
+
+  template<typename _Tp0, typename _Tp1, typename _Tp2, typename... _Rest>
+    struct _Nth_type<2, _Tp0, _Tp1, _Tp2, _Rest...>
+    { using type = _Tp2; };
+
+  template<size_t _Np, typename _Tp0, typename _Tp1, typename _Tp2,
+	   typename... _Rest>
+#if __cpp_concepts
+    requires (_Np >= 3)
+#endif
+    struct _Nth_type<_Np, _Tp0, _Tp1, _Tp2, _Rest...>
+    : _Nth_type<_Np - 3, _Rest...>
+    { };
+
+#if ! __cpp_concepts // Need additional specializations to avoid ambiguities.
+  template<typename _Tp0, typename _Tp1, typename... _Rest>
+    struct _Nth_type<0, _Tp0, _Tp1, _Rest...>
+    { using type = _Tp0; };
+
+  template<typename _Tp0, typename _Tp1, typename _Tp2, typename... _Rest>
+    struct _Nth_type<0, _Tp0, _Tp1, _Tp2, _Rest...>
+    { using type = _Tp0; };
+
+  template<typename _Tp0, typename _Tp1, typename _Tp2, typename... _Rest>
+    struct _Nth_type<1, _Tp0, _Tp1, _Tp2, _Rest...>
+    { using type = _Tp1; };
+#endif
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif // C++11
+#endif /* _GLIBCXX_UTILITY_H */
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@valarray_after.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@valarray_after.h
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@valarray_after.h
@@ -0,0 +1,556 @@
+// The template and inlines for the -*- C++ -*- internal _Meta class.
+
+// Copyright (C) 1997-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/valarray_after.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{valarray}
+ */
+
+// Written by Gabriel Dos Reis <Gabriel.Dos-Reis@cmla.ens-cachan.fr>
+
+#ifndef _VALARRAY_AFTER_H
+#define _VALARRAY_AFTER_H 1
+
+#pragma GCC system_header
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+namespace __detail
+{
+  //
+  // gslice_array closure.
+  //
+  template<class _Dom>
+    class _GBase
+    {
+    public:
+      typedef typename _Dom::value_type value_type;
+      
+      _GBase (const _Dom& __e, const valarray<size_t>& __i)
+      : _M_expr (__e), _M_index(__i) {}
+      
+      value_type
+      operator[] (size_t __i) const
+      { return _M_expr[_M_index[__i]]; }
+      
+      size_t
+      size () const
+      { return _M_index.size(); }
+
+    private:
+      typename _ValArrayRef<_Dom>::__type	_M_expr;
+      const valarray<size_t>&			_M_index;
+    };
+
+  template<typename _Tp>
+    class _GBase<_Array<_Tp> >
+    {
+    public:
+      typedef _Tp value_type;
+      
+      _GBase (_Array<_Tp> __a, const valarray<size_t>& __i)
+      : _M_array (__a), _M_index(__i) {}
+      
+      value_type
+      operator[] (size_t __i) const
+      { return _M_array._M_data[_M_index[__i]]; }
+      
+      size_t
+      size () const
+      { return _M_index.size(); }
+
+    private:
+      const _Array<_Tp>       _M_array;
+      const valarray<size_t>& _M_index;
+    };
+
+  template<class _Dom>
+    struct _GClos<_Expr, _Dom>
+    : _GBase<_Dom>
+    {
+      typedef _GBase<_Dom> _Base;
+      typedef typename _Base::value_type value_type;
+      
+      _GClos (const _Dom& __e, const valarray<size_t>& __i)
+      : _Base (__e, __i) {}
+    };
+
+  template<typename _Tp>
+    struct _GClos<_ValArray, _Tp>
+    : _GBase<_Array<_Tp> >
+    {
+      typedef _GBase<_Array<_Tp> > _Base;
+      typedef typename _Base::value_type value_type;
+      
+      _GClos (_Array<_Tp> __a, const valarray<size_t>& __i)
+      : _Base (__a, __i) {}
+    };
+
+  //
+  // indirect_array closure
+  //
+  template<class _Dom>
+    class _IBase
+    {
+    public:
+      typedef typename _Dom::value_type value_type;
+
+      _IBase (const _Dom& __e, const valarray<size_t>& __i)
+      : _M_expr (__e), _M_index (__i) {}
+      
+      value_type
+      operator[] (size_t __i) const
+      { return _M_expr[_M_index[__i]]; }
+      
+      size_t
+      size() const
+      { return _M_index.size(); }
+
+    private:
+      typename _ValArrayRef<_Dom>::__type	_M_expr;
+      const valarray<size_t>&			_M_index;
+    };
+
+  template<class _Dom>
+    struct _IClos<_Expr, _Dom>
+    : _IBase<_Dom>
+    {
+      typedef _IBase<_Dom> _Base;
+      typedef typename _Base::value_type value_type;
+      
+      _IClos (const _Dom& __e, const valarray<size_t>& __i)
+      : _Base (__e, __i) {}
+    };
+
+  template<typename _Tp>
+    struct _IClos<_ValArray, _Tp>
+    : _IBase<valarray<_Tp> >
+    {
+      typedef _IBase<valarray<_Tp> > _Base;
+      typedef _Tp value_type;
+      
+      _IClos (const valarray<_Tp>& __a, const valarray<size_t>& __i)
+      : _Base (__a, __i) {}
+    };
+} // namespace __detail
+  
+  //
+  // class _Expr
+  //
+  template<class _Clos, typename _Tp>
+    class _Expr
+    {
+    public:
+      typedef _Tp value_type;
+
+      _Expr(const _Clos&);
+
+      const _Clos& operator()() const;
+
+      value_type operator[](size_t) const;
+      valarray<value_type> operator[](slice) const;
+      valarray<value_type> operator[](const gslice&) const;
+      valarray<value_type> operator[](const valarray<bool>&) const;
+      valarray<value_type> operator[](const valarray<size_t>&) const;
+
+      _Expr<_UnClos<__unary_plus, std::_Expr, _Clos>, value_type>
+      operator+() const;
+
+      _Expr<_UnClos<__negate, std::_Expr, _Clos>, value_type>
+      operator-() const;
+
+      _Expr<_UnClos<__bitwise_not, std::_Expr, _Clos>, value_type>
+      operator~() const;
+
+      _Expr<_UnClos<__logical_not, std::_Expr, _Clos>, bool>
+      operator!() const;
+
+      size_t size() const;
+      value_type sum() const;
+
+      valarray<value_type> shift(int) const;
+      valarray<value_type> cshift(int) const;
+
+      value_type min() const;
+      value_type max() const;
+
+      valarray<value_type> apply(value_type (*)(const value_type&)) const;
+      valarray<value_type> apply(value_type (*)(value_type)) const;
+
+    private:
+      const _Clos _M_closure;
+    };
+
+  template<class _Clos, typename _Tp>
+    inline
+    _Expr<_Clos, _Tp>::_Expr(const _Clos& __c) : _M_closure(__c) {}
+
+  template<class _Clos, typename _Tp>
+    inline const _Clos&
+    _Expr<_Clos, _Tp>::operator()() const
+    { return _M_closure; }
+
+  template<class _Clos, typename _Tp>
+    inline _Tp
+    _Expr<_Clos, _Tp>::operator[](size_t __i) const
+    { return _M_closure[__i]; }
+
+  template<class _Clos, typename _Tp>
+    inline valarray<_Tp>
+    _Expr<_Clos, _Tp>::operator[](slice __s) const
+    {
+      valarray<_Tp> __v = valarray<_Tp>(*this)[__s];
+      return __v;
+    }
+
+  template<class _Clos, typename _Tp>
+    inline valarray<_Tp>
+    _Expr<_Clos, _Tp>::operator[](const gslice& __gs) const
+    {
+      valarray<_Tp> __v = valarray<_Tp>(*this)[__gs];
+      return __v;
+    }
+
+  template<class _Clos, typename _Tp>
+    inline valarray<_Tp>
+    _Expr<_Clos, _Tp>::operator[](const valarray<bool>& __m) const
+    {
+      valarray<_Tp> __v = valarray<_Tp>(*this)[__m];
+      return __v;
+    }
+
+  template<class _Clos, typename _Tp>
+    inline valarray<_Tp>
+    _Expr<_Clos, _Tp>::operator[](const valarray<size_t>& __i) const
+    {
+      valarray<_Tp> __v = valarray<_Tp>(*this)[__i];
+      return __v;
+    }
+
+  template<class _Clos, typename _Tp>
+    inline size_t
+    _Expr<_Clos, _Tp>::size() const
+    { return _M_closure.size(); }
+
+  template<class _Clos, typename _Tp>
+    inline valarray<_Tp>
+    _Expr<_Clos, _Tp>::shift(int __n) const
+    {
+      valarray<_Tp> __v = valarray<_Tp>(*this).shift(__n);
+      return __v;
+    }
+
+  template<class _Clos, typename _Tp>
+    inline valarray<_Tp>
+    _Expr<_Clos, _Tp>::cshift(int __n) const
+    {
+      valarray<_Tp> __v = valarray<_Tp>(*this).cshift(__n);
+      return __v;
+    }
+
+  template<class _Clos, typename _Tp>
+    inline valarray<_Tp>
+    _Expr<_Clos, _Tp>::apply(_Tp __f(const _Tp&)) const
+    {
+      valarray<_Tp> __v = valarray<_Tp>(*this).apply(__f);
+      return __v;
+    }
+
+  template<class _Clos, typename _Tp>
+    inline valarray<_Tp>
+    _Expr<_Clos, _Tp>::apply(_Tp __f(_Tp)) const
+    {
+      valarray<_Tp> __v = valarray<_Tp>(*this).apply(__f);
+      return __v;
+    }
+
+  // XXX: replace this with a more robust summation algorithm.
+  template<class _Clos, typename _Tp>
+    inline _Tp
+    _Expr<_Clos, _Tp>::sum() const
+    {
+      size_t __n = _M_closure.size();
+      if (__n == 0)
+	return _Tp();
+      else
+	{
+	  _Tp __s = _M_closure[--__n];
+	  while (__n != 0)
+	    __s += _M_closure[--__n];
+	  return __s;
+        }
+    }
+
+  template<class _Clos, typename _Tp>
+    inline _Tp
+    _Expr<_Clos, _Tp>::min() const
+    { return __valarray_min(_M_closure); }
+
+  template<class _Clos, typename _Tp>
+    inline _Tp
+    _Expr<_Clos, _Tp>::max() const
+    { return __valarray_max(_M_closure); }
+
+  template<class _Dom, typename _Tp>
+    inline _Expr<_UnClos<__logical_not, _Expr, _Dom>, bool>
+    _Expr<_Dom, _Tp>::operator!() const
+    {
+      typedef _UnClos<__logical_not, std::_Expr, _Dom> _Closure;
+      return _Expr<_Closure, bool>(_Closure(this->_M_closure));
+    }
+
+#define _DEFINE_EXPR_UNARY_OPERATOR(_Op, _Name)                           \
+  template<class _Dom, typename _Tp>                                      \
+    inline _Expr<_UnClos<_Name, std::_Expr, _Dom>, _Tp>                   \
+    _Expr<_Dom, _Tp>::operator _Op() const                                \
+    {                                                                     \
+      typedef _UnClos<_Name, std::_Expr, _Dom> _Closure;                  \
+      return _Expr<_Closure, _Tp>(_Closure(this->_M_closure));            \
+    }
+
+    _DEFINE_EXPR_UNARY_OPERATOR(+, struct std::__unary_plus)
+    _DEFINE_EXPR_UNARY_OPERATOR(-, struct std::__negate)
+    _DEFINE_EXPR_UNARY_OPERATOR(~, struct std::__bitwise_not)
+
+#undef _DEFINE_EXPR_UNARY_OPERATOR
+
+#define _DEFINE_EXPR_BINARY_OPERATOR(_Op, _Name)                        \
+  template<class _Dom1, class _Dom2>					\
+    inline _Expr<_BinClos<_Name, _Expr, _Expr, _Dom1, _Dom2>,           \
+           typename __fun<_Name, typename _Dom1::value_type>::result_type> \
+    operator _Op(const _Expr<_Dom1, typename _Dom1::value_type>& __v,   \
+	         const _Expr<_Dom2, typename _Dom2::value_type>& __w)   \
+    {                                                                   \
+      typedef typename _Dom1::value_type _Arg;                          \
+      typedef typename __fun<_Name, _Arg>::result_type _Value;          \
+      typedef _BinClos<_Name, _Expr, _Expr, _Dom1, _Dom2> _Closure;     \
+      return _Expr<_Closure, _Value>(_Closure(__v(), __w()));           \
+    }                                                                   \
+                                                                        \
+  template<class _Dom>                                                  \
+    inline _Expr<_BinClos<_Name, _Expr, _Constant, _Dom,                \
+                          typename _Dom::value_type>,                   \
+             typename __fun<_Name, typename _Dom::value_type>::result_type> \
+    operator _Op(const _Expr<_Dom, typename _Dom::value_type>& __v,     \
+                 const typename _Dom::value_type& __t)                  \
+    {                                                                   \
+      typedef typename _Dom::value_type _Arg;                           \
+      typedef typename __fun<_Name, _Arg>::result_type _Value;          \
+      typedef _BinClos<_Name, _Expr, _Constant, _Dom, _Arg> _Closure;   \
+      return _Expr<_Closure, _Value>(_Closure(__v(), __t));             \
+    }                                                                   \
+                                                                        \
+  template<class _Dom>                                                  \
+    inline _Expr<_BinClos<_Name, _Constant, _Expr,                      \
+                          typename _Dom::value_type, _Dom>,             \
+             typename __fun<_Name, typename _Dom::value_type>::result_type> \
+    operator _Op(const typename _Dom::value_type& __t,                  \
+                 const _Expr<_Dom, typename _Dom::value_type>& __v)     \
+    {                                                                   \
+      typedef typename _Dom::value_type _Arg;                           \
+      typedef typename __fun<_Name, _Arg>::result_type _Value;          \
+      typedef _BinClos<_Name, _Constant, _Expr, _Arg, _Dom> _Closure;   \
+      return _Expr<_Closure, _Value>(_Closure(__t, __v()));             \
+    }                                                                   \
+                                                                        \
+  template<class _Dom>                                                  \
+    inline _Expr<_BinClos<_Name, _Expr, _ValArray,                      \
+                          _Dom, typename _Dom::value_type>,             \
+             typename __fun<_Name, typename _Dom::value_type>::result_type> \
+    operator _Op(const _Expr<_Dom,typename _Dom::value_type>& __e,      \
+                 const valarray<typename _Dom::value_type>& __v)        \
+    {                                                                   \
+      typedef typename _Dom::value_type _Arg;                           \
+      typedef typename __fun<_Name, _Arg>::result_type _Value;          \
+      typedef _BinClos<_Name, _Expr, _ValArray, _Dom, _Arg> _Closure;   \
+      return _Expr<_Closure, _Value>(_Closure(__e(), __v));             \
+    }                                                                   \
+                                                                        \
+  template<class _Dom>                                                  \
+    inline _Expr<_BinClos<_Name, _ValArray, _Expr,                      \
+                 typename _Dom::value_type, _Dom>,                      \
+             typename __fun<_Name, typename _Dom::value_type>::result_type> \
+    operator _Op(const valarray<typename _Dom::value_type>& __v,        \
+                 const _Expr<_Dom, typename _Dom::value_type>& __e)     \
+    {                                                                   \
+      typedef typename _Dom::value_type _Tp;                            \
+      typedef typename __fun<_Name, _Tp>::result_type _Value;           \
+      typedef _BinClos<_Name, _ValArray, _Expr, _Tp, _Dom> _Closure;    \
+      return _Expr<_Closure, _Value>(_Closure(__v, __e ()));            \
+    }
+
+    _DEFINE_EXPR_BINARY_OPERATOR(+, struct std::__plus)
+    _DEFINE_EXPR_BINARY_OPERATOR(-, struct std::__minus)
+    _DEFINE_EXPR_BINARY_OPERATOR(*, struct std::__multiplies)
+    _DEFINE_EXPR_BINARY_OPERATOR(/, struct std::__divides)
+    _DEFINE_EXPR_BINARY_OPERATOR(%, struct std::__modulus)
+    _DEFINE_EXPR_BINARY_OPERATOR(^, struct std::__bitwise_xor)
+    _DEFINE_EXPR_BINARY_OPERATOR(&, struct std::__bitwise_and)
+    _DEFINE_EXPR_BINARY_OPERATOR(|, struct std::__bitwise_or)
+    _DEFINE_EXPR_BINARY_OPERATOR(<<, struct std::__shift_left)
+    _DEFINE_EXPR_BINARY_OPERATOR(>>, struct std::__shift_right)
+    _DEFINE_EXPR_BINARY_OPERATOR(&&, struct std::__logical_and)
+    _DEFINE_EXPR_BINARY_OPERATOR(||, struct std::__logical_or)
+    _DEFINE_EXPR_BINARY_OPERATOR(==, struct std::__equal_to)
+    _DEFINE_EXPR_BINARY_OPERATOR(!=, struct std::__not_equal_to)
+    _DEFINE_EXPR_BINARY_OPERATOR(<, struct std::__less)
+    _DEFINE_EXPR_BINARY_OPERATOR(>, struct std::__greater)
+    _DEFINE_EXPR_BINARY_OPERATOR(<=, struct std::__less_equal)
+    _DEFINE_EXPR_BINARY_OPERATOR(>=, struct std::__greater_equal)
+
+#undef _DEFINE_EXPR_BINARY_OPERATOR
+
+#define _DEFINE_EXPR_UNARY_FUNCTION(_Name, _UName)                       \
+  template<class _Dom>                                                   \
+    inline _Expr<_UnClos<_UName, _Expr, _Dom>,                           \
+                 typename _Dom::value_type>                              \
+    _Name(const _Expr<_Dom, typename _Dom::value_type>& __e)             \
+    {                                                                    \
+      typedef typename _Dom::value_type _Tp;                             \
+      typedef _UnClos<_UName, _Expr, _Dom> _Closure;                     \
+      return _Expr<_Closure, _Tp>(_Closure(__e()));                      \
+    }                                                                    \
+                                                                         \
+  template<typename _Tp>                                                 \
+    inline _Expr<_UnClos<_UName, _ValArray, _Tp>, _Tp>                   \
+    _Name(const valarray<_Tp>& __v)                                      \
+    {                                                                    \
+      typedef _UnClos<_UName, _ValArray, _Tp> _Closure;                  \
+      return _Expr<_Closure, _Tp>(_Closure(__v));                        \
+    }
+
+    _DEFINE_EXPR_UNARY_FUNCTION(abs, struct std::_Abs)
+    _DEFINE_EXPR_UNARY_FUNCTION(cos, struct std::_Cos)
+    _DEFINE_EXPR_UNARY_FUNCTION(acos, struct std::_Acos)
+    _DEFINE_EXPR_UNARY_FUNCTION(cosh, struct std::_Cosh)
+    _DEFINE_EXPR_UNARY_FUNCTION(sin, struct std::_Sin)
+    _DEFINE_EXPR_UNARY_FUNCTION(asin, struct std::_Asin)
+    _DEFINE_EXPR_UNARY_FUNCTION(sinh, struct std::_Sinh)
+    _DEFINE_EXPR_UNARY_FUNCTION(tan, struct std::_Tan)
+    _DEFINE_EXPR_UNARY_FUNCTION(tanh, struct std::_Tanh)
+    _DEFINE_EXPR_UNARY_FUNCTION(atan, struct std::_Atan)
+    _DEFINE_EXPR_UNARY_FUNCTION(exp, struct std::_Exp)
+    _DEFINE_EXPR_UNARY_FUNCTION(log, struct std::_Log)
+    _DEFINE_EXPR_UNARY_FUNCTION(log10, struct std::_Log10)
+    _DEFINE_EXPR_UNARY_FUNCTION(sqrt, struct std::_Sqrt)
+
+#undef _DEFINE_EXPR_UNARY_FUNCTION
+
+#define _DEFINE_EXPR_BINARY_FUNCTION(_Fun, _UFun)		       \
+  template<class _Dom1, class _Dom2>                                   \
+    inline _Expr<_BinClos<_UFun, _Expr, _Expr, _Dom1, _Dom2>,          \
+		 typename _Dom1::value_type>                           \
+    _Fun(const _Expr<_Dom1, typename _Dom1::value_type>& __e1,         \
+	 const _Expr<_Dom2, typename _Dom2::value_type>& __e2)	       \
+    {                                                                  \
+      typedef typename _Dom1::value_type _Tp;                          \
+      typedef _BinClos<_UFun, _Expr, _Expr, _Dom1, _Dom2> _Closure;    \
+      return _Expr<_Closure, _Tp>(_Closure(__e1(), __e2()));           \
+    }                                                                  \
+                                                                       \
+  template<class _Dom>                                                 \
+    inline _Expr<_BinClos<_UFun, _Expr, _ValArray, _Dom,               \
+			  typename _Dom::value_type>,                  \
+		 typename _Dom::value_type>                            \
+    _Fun(const _Expr<_Dom, typename _Dom::value_type>& __e,            \
+	 const valarray<typename _Dom::value_type>& __v)               \
+    {                                                                  \
+      typedef typename _Dom::value_type _Tp;                           \
+      typedef _BinClos<_UFun, _Expr, _ValArray, _Dom, _Tp> _Closure;   \
+      return _Expr<_Closure, _Tp>(_Closure(__e(), __v));               \
+    }                                                                  \
+                                                                       \
+  template<class _Dom>                                                 \
+    inline _Expr<_BinClos<_UFun, _ValArray, _Expr,                     \
+			  typename _Dom::value_type, _Dom>,            \
+		 typename _Dom::value_type>                            \
+    _Fun(const valarray<typename _Dom::valarray>& __v,                 \
+	 const _Expr<_Dom, typename _Dom::value_type>& __e)            \
+    {                                                                  \
+      typedef typename _Dom::value_type _Tp;                           \
+      typedef _BinClos<_UFun, _ValArray, _Expr, _Tp, _Dom> _Closure;   \
+      return _Expr<_Closure, _Tp>(_Closure(__v, __e()));               \
+    }                                                                  \
+                                                                       \
+  template<class _Dom>                                                 \
+    inline _Expr<_BinClos<_UFun, _Expr, _Constant, _Dom,               \
+			  typename _Dom::value_type>,                  \
+		 typename _Dom::value_type>                            \
+    _Fun(const _Expr<_Dom, typename _Dom::value_type>& __e,            \
+	 const typename _Dom::value_type& __t)                         \
+    {                                                                  \
+      typedef typename _Dom::value_type _Tp;                           \
+      typedef _BinClos<_UFun, _Expr, _Constant, _Dom, _Tp> _Closure;   \
+      return _Expr<_Closure, _Tp>(_Closure(__e(), __t));               \
+    }                                                                  \
+                                                                       \
+  template<class _Dom>                                                 \
+    inline _Expr<_BinClos<_UFun, _Constant, _Expr,                     \
+			  typename _Dom::value_type, _Dom>,            \
+		 typename _Dom::value_type>                            \
+    _Fun(const typename _Dom::value_type& __t,                         \
+	 const _Expr<_Dom, typename _Dom::value_type>& __e)            \
+    {                                                                  \
+      typedef typename _Dom::value_type _Tp;                           \
+      typedef _BinClos<_UFun, _Constant, _Expr, _Tp, _Dom> _Closure;   \
+      return _Expr<_Closure, _Tp>(_Closure(__t, __e()));               \
+    }                                                                  \
+                                                                       \
+  template<typename _Tp>                                               \
+    inline _Expr<_BinClos<_UFun, _ValArray, _ValArray, _Tp, _Tp>, _Tp> \
+    _Fun(const valarray<_Tp>& __v, const valarray<_Tp>& __w)           \
+    {                                                                  \
+      typedef _BinClos<_UFun, _ValArray, _ValArray, _Tp, _Tp> _Closure;\
+      return _Expr<_Closure, _Tp>(_Closure(__v, __w));                 \
+    }                                                                  \
+                                                                       \
+  template<typename _Tp>                                               \
+    inline _Expr<_BinClos<_UFun, _ValArray, _Constant, _Tp, _Tp>, _Tp> \
+    _Fun(const valarray<_Tp>& __v,				       \
+	 const typename valarray<_Tp>::value_type& __t)                \
+    {                                                                  \
+      typedef _BinClos<_UFun, _ValArray, _Constant, _Tp, _Tp> _Closure;\
+      return _Expr<_Closure, _Tp>(_Closure(__v, __t));                 \
+    }                                                                  \
+								       \
+  template<typename _Tp>                                               \
+    inline _Expr<_BinClos<_UFun, _Constant, _ValArray, _Tp, _Tp>, _Tp> \
+    _Fun(const typename valarray<_Tp>::value_type& __t,		       \
+	 const valarray<_Tp>& __v)                                     \
+    {                                                                  \
+      typedef _BinClos<_UFun, _Constant, _ValArray, _Tp, _Tp> _Closure;\
+      return _Expr<_Closure, _Tp>(_Closure(__t, __v));                 \
+    }
+
+_DEFINE_EXPR_BINARY_FUNCTION(atan2, struct std::_Atan2)
+_DEFINE_EXPR_BINARY_FUNCTION(pow, struct std::_Pow)
+
+#undef _DEFINE_EXPR_BINARY_FUNCTION
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif /* _CPP_VALARRAY_AFTER_H */
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@valarray_array.h
@@ -0,0 +1,677 @@
+// The template and inlines for the -*- C++ -*- internal _Array helper class.
+
+// Copyright (C) 1997-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/valarray_array.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{valarray}
+ */
+
+// Written by Gabriel Dos Reis <Gabriel.Dos-Reis@DPTMaths.ENS-Cachan.Fr>
+
+#ifndef _VALARRAY_ARRAY_H
+#define _VALARRAY_ARRAY_H 1
+
+#pragma GCC system_header
+
+#include <bits/c++config.h>
+#include <bits/cpp_type_traits.h>
+#include <cstdlib>
+#include <new>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  //
+  // Helper functions on raw pointers
+  //
+
+  // We get memory the old fashioned way
+  template<typename _Tp>
+    _Tp*
+    __valarray_get_storage(size_t) __attribute__((__malloc__));
+
+  template<typename _Tp>
+    inline _Tp*
+    __valarray_get_storage(size_t __n)
+    { return static_cast<_Tp*>(operator new(__n * sizeof(_Tp))); }
+
+  // Return memory to the system
+  inline void
+  __valarray_release_memory(void* __p)
+  { operator delete(__p); }
+
+  // Turn a raw-memory into an array of _Tp filled with _Tp()
+  // This is required in 'valarray<T> v(n);'
+  template<typename _Tp, bool>
+    struct _Array_default_ctor
+    {
+      // Please note that this isn't exception safe.  But
+      // valarrays aren't required to be exception safe.
+      inline static void
+      _S_do_it(_Tp* __b, _Tp* __e)
+      {
+	while (__b != __e)
+	  new(__b++) _Tp();
+      }
+    };
+
+  template<typename _Tp>
+    struct _Array_default_ctor<_Tp, true>
+    {
+      // For fundamental types, it suffices to say 'memset()'
+      inline static void
+      _S_do_it(_Tp* __b, _Tp* __e)
+      { __builtin_memset(__b, 0, (__e - __b) * sizeof(_Tp)); }
+    };
+
+  template<typename _Tp>
+    inline void
+    __valarray_default_construct(_Tp* __b, _Tp* __e)
+    {
+      _Array_default_ctor<_Tp, __is_scalar<_Tp>::__value>::_S_do_it(__b, __e);
+    }
+
+  // Turn a raw-memory into an array of _Tp filled with __t
+  // This is the required in valarray<T> v(n, t).  Also
+  // used in valarray<>::resize().
+  template<typename _Tp, bool>
+    struct _Array_init_ctor
+    {
+      // Please note that this isn't exception safe.  But
+      // valarrays aren't required to be exception safe.
+      inline static void
+      _S_do_it(_Tp* __b, _Tp* __e, const _Tp __t)
+      {
+	while (__b != __e)
+	  new(__b++) _Tp(__t);
+      }
+    };
+
+  template<typename _Tp>
+    struct _Array_init_ctor<_Tp, true>
+    {
+      inline static void
+      _S_do_it(_Tp* __b, _Tp* __e, const _Tp __t)
+      {
+	while (__b != __e)
+	  *__b++ = __t;
+      }
+    };
+
+  template<typename _Tp>
+    inline void
+    __valarray_fill_construct(_Tp* __b, _Tp* __e, const _Tp __t)
+    {
+      _Array_init_ctor<_Tp, __is_trivial(_Tp)>::_S_do_it(__b, __e, __t);
+    }
+
+  //
+  // copy-construct raw array [__o, *) from plain array [__b, __e)
+  // We can't just say 'memcpy()'
+  //
+  template<typename _Tp, bool>
+    struct _Array_copy_ctor
+    {
+      // Please note that this isn't exception safe.  But
+      // valarrays aren't required to be exception safe.
+      inline static void
+      _S_do_it(const _Tp* __b, const _Tp* __e, _Tp* __restrict__ __o)
+      {
+	while (__b != __e)
+	  new(__o++) _Tp(*__b++);
+      }
+    };
+
+  template<typename _Tp>
+    struct _Array_copy_ctor<_Tp, true>
+    {
+      inline static void
+      _S_do_it(const _Tp* __b, const _Tp* __e, _Tp* __restrict__ __o)
+      {
+	if (__b)
+	  __builtin_memcpy(__o, __b, (__e - __b) * sizeof(_Tp));
+      }
+    };
+
+  template<typename _Tp>
+    inline void
+    __valarray_copy_construct(const _Tp* __b, const _Tp* __e,
+			      _Tp* __restrict__ __o)
+    {
+      _Array_copy_ctor<_Tp, __is_trivial(_Tp)>::_S_do_it(__b, __e, __o);
+    }
+
+  // copy-construct raw array [__o, *) from strided array __a[<__n : __s>]
+  template<typename _Tp>
+    inline void
+    __valarray_copy_construct (const _Tp* __restrict__ __a, size_t __n,
+			       size_t __s, _Tp* __restrict__ __o)
+    {
+      if (__is_trivial(_Tp))
+	while (__n--)
+	  {
+	    *__o++ = *__a;
+	    __a += __s;
+	  }
+      else
+	while (__n--)
+	  {
+	    new(__o++) _Tp(*__a);
+	    __a += __s;
+	  }
+    }
+
+  // copy-construct raw array [__o, *) from indexed array __a[__i[<__n>]]
+  template<typename _Tp>
+    inline void
+    __valarray_copy_construct (const _Tp* __restrict__ __a,
+			       const size_t* __restrict__ __i,
+			       _Tp* __restrict__ __o, size_t __n)
+    {
+      if (__is_trivial(_Tp))
+	while (__n--)
+	  *__o++ = __a[*__i++];
+      else
+	while (__n--)
+	  new (__o++) _Tp(__a[*__i++]);
+    }
+
+  // Do the necessary cleanup when we're done with arrays.
+  template<typename _Tp>
+    inline void
+    __valarray_destroy_elements(_Tp* __b, _Tp* __e)
+    {
+      if (!__is_trivial(_Tp))
+	while (__b != __e)
+	  {
+	    __b->~_Tp();
+	    ++__b;
+	  }
+    }
+
+  // Fill a plain array __a[<__n>] with __t
+  template<typename _Tp>
+    inline void
+    __valarray_fill(_Tp* __restrict__ __a, size_t __n, const _Tp& __t)
+    {
+      while (__n--)
+	*__a++ = __t;
+    }
+  
+  // fill strided array __a[<__n-1 : __s>] with __t
+  template<typename _Tp>
+    inline void
+    __valarray_fill(_Tp* __restrict__ __a, size_t __n,
+		    size_t __s, const _Tp& __t)
+    { 
+      for (size_t __i = 0; __i < __n; ++__i, __a += __s)
+	*__a = __t;
+    }
+
+  // fill indirect array __a[__i[<__n>]] with __i
+  template<typename _Tp>
+    inline void
+    __valarray_fill(_Tp* __restrict__ __a, const size_t* __restrict__ __i,
+		    size_t __n, const _Tp& __t)
+    {
+      for (size_t __j = 0; __j < __n; ++__j, ++__i)
+	__a[*__i] = __t;
+    }
+  
+  // copy plain array __a[<__n>] in __b[<__n>]
+  // For non-fundamental types, it is wrong to say 'memcpy()'
+  template<typename _Tp, bool>
+    struct _Array_copier
+    {
+      inline static void
+      _S_do_it(const _Tp* __restrict__ __a, size_t __n, _Tp* __restrict__ __b)
+      {
+	while(__n--)
+	  *__b++ = *__a++;
+      }
+    };
+
+  template<typename _Tp>
+    struct _Array_copier<_Tp, true>
+    {
+      inline static void
+      _S_do_it(const _Tp* __restrict__ __a, size_t __n, _Tp* __restrict__ __b)
+      {
+	if (__n != 0)
+	  __builtin_memcpy(__b, __a, __n * sizeof (_Tp));
+      }
+    };
+
+  // Copy a plain array __a[<__n>] into a play array __b[<>]
+  template<typename _Tp>
+    inline void
+    __valarray_copy(const _Tp* __restrict__ __a, size_t __n,
+		    _Tp* __restrict__ __b)
+    {
+      _Array_copier<_Tp, __is_trivial(_Tp)>::_S_do_it(__a, __n, __b);
+    }
+
+  // Copy strided array __a[<__n : __s>] in plain __b[<__n>]
+  template<typename _Tp>
+    inline void
+    __valarray_copy(const _Tp* __restrict__ __a, size_t __n, size_t __s,
+		    _Tp* __restrict__ __b)
+    {
+      for (size_t __i = 0; __i < __n; ++__i, ++__b, __a += __s)
+	*__b = *__a;
+    }
+
+  // Copy a plain array  __a[<__n>] into a strided array __b[<__n : __s>]
+  template<typename _Tp>
+    inline void
+    __valarray_copy(const _Tp* __restrict__ __a, _Tp* __restrict__ __b,
+		    size_t __n, size_t __s)
+    {
+      for (size_t __i = 0; __i < __n; ++__i, ++__a, __b += __s)
+	*__b = *__a;
+    }
+
+  // Copy strided array __src[<__n : __s1>] into another
+  // strided array __dst[< : __s2>].  Their sizes must match.
+  template<typename _Tp>
+    inline void
+    __valarray_copy(const _Tp* __restrict__ __src, size_t __n, size_t __s1,
+		    _Tp* __restrict__ __dst, size_t __s2)
+    {
+      for (size_t __i = 0; __i < __n; ++__i)
+	__dst[__i * __s2] = __src[__i * __s1];
+    }
+
+  // Copy an indexed array __a[__i[<__n>]] in plain array __b[<__n>]
+  template<typename _Tp>
+    inline void
+    __valarray_copy(const _Tp* __restrict__ __a,
+		    const size_t* __restrict__ __i,
+		    _Tp* __restrict__ __b, size_t __n)
+    {
+      for (size_t __j = 0; __j < __n; ++__j, ++__b, ++__i)
+	*__b = __a[*__i];
+    }
+
+  // Copy a plain array __a[<__n>] in an indexed array __b[__i[<__n>]]
+  template<typename _Tp>
+    inline void
+    __valarray_copy(const _Tp* __restrict__ __a, size_t __n,
+		    _Tp* __restrict__ __b, const size_t* __restrict__ __i)
+    {
+      for (size_t __j = 0; __j < __n; ++__j, ++__a, ++__i)
+	__b[*__i] = *__a;
+    }
+
+  // Copy the __n first elements of an indexed array __src[<__i>] into
+  // another indexed array __dst[<__j>].
+  template<typename _Tp>
+    inline void
+    __valarray_copy(const _Tp* __restrict__ __src, size_t __n,
+		    const size_t* __restrict__ __i,
+		    _Tp* __restrict__ __dst, const size_t* __restrict__ __j)
+    {
+      for (size_t __k = 0; __k < __n; ++__k)
+	__dst[*__j++] = __src[*__i++];
+    }
+
+  //
+  // Compute the sum of elements in range [__f, __l) which must not be empty.
+  // This is a naive algorithm.  It suffers from cancelling.
+  // In the future try to specialize for _Tp = float, double, long double
+  // using a more accurate algorithm.
+  //
+  template<typename _Tp>
+    inline _Tp
+    __valarray_sum(const _Tp* __f, const _Tp* __l)
+    {
+      _Tp __r = *__f++;
+      while (__f != __l)
+	__r += *__f++;
+      return __r;
+    }
+
+  // Compute the min/max of an array-expression
+  template<typename _Ta>
+    inline typename _Ta::value_type
+    __valarray_min(const _Ta& __a)
+    {
+      size_t __s = __a.size();
+      typedef typename _Ta::value_type _Value_type;
+      _Value_type __r = __s == 0 ? _Value_type() : __a[0];
+      for (size_t __i = 1; __i < __s; ++__i)
+	{
+	  _Value_type __t = __a[__i];
+	  if (__t < __r)
+	    __r = __t;
+	}
+      return __r;
+    }
+
+  template<typename _Ta>
+    inline typename _Ta::value_type
+    __valarray_max(const _Ta& __a)
+    {
+      size_t __s = __a.size();
+      typedef typename _Ta::value_type _Value_type;
+      _Value_type __r = __s == 0 ? _Value_type() : __a[0];
+      for (size_t __i = 1; __i < __s; ++__i)
+	{
+	  _Value_type __t = __a[__i];
+	  if (__t > __r)
+	    __r = __t;
+	}
+      return __r;
+    }
+
+  //
+  // Helper class _Array, first layer of valarray abstraction.
+  // All operations on valarray should be forwarded to this class
+  // whenever possible. -- gdr
+  //
+
+  template<typename _Tp>
+    struct _Array
+    {
+      explicit _Array(_Tp* const __restrict__);
+      explicit _Array(const valarray<_Tp>&);
+      _Array(const _Tp* __restrict__, size_t);
+      
+      _Tp* begin() const;
+      
+      _Tp* const __restrict__ _M_data;
+    };
+
+
+  // Copy-construct plain array __b[<__n>] from indexed array __a[__i[<__n>]]
+  template<typename _Tp>
+    inline void
+    __valarray_copy_construct(_Array<_Tp> __a, _Array<size_t> __i,
+			      _Array<_Tp> __b, size_t __n)
+    { std::__valarray_copy_construct(__a._M_data, __i._M_data,
+				     __b._M_data, __n); }
+
+  // Copy-construct plain array __b[<__n>] from strided array __a[<__n : __s>]
+  template<typename _Tp>
+    inline void
+    __valarray_copy_construct(_Array<_Tp> __a, size_t __n, size_t __s,
+			      _Array<_Tp> __b)
+    { std::__valarray_copy_construct(__a._M_data, __n, __s, __b._M_data); }
+
+  template<typename _Tp>
+    inline void
+    __valarray_fill (_Array<_Tp> __a, size_t __n, const _Tp& __t)
+    { std::__valarray_fill(__a._M_data, __n, __t); }
+
+  template<typename _Tp>
+    inline void
+    __valarray_fill(_Array<_Tp> __a, size_t __n, size_t __s, const _Tp& __t)
+    { std::__valarray_fill(__a._M_data, __n, __s, __t); }
+
+  template<typename _Tp>
+    inline void
+    __valarray_fill(_Array<_Tp> __a, _Array<size_t> __i,
+		    size_t __n, const _Tp& __t)
+    { std::__valarray_fill(__a._M_data, __i._M_data, __n, __t); }
+
+  // Copy a plain array __a[<__n>] into a play array __b[<>]
+  template<typename _Tp>
+    inline void
+    __valarray_copy(_Array<_Tp> __a, size_t __n, _Array<_Tp> __b)
+    { std::__valarray_copy(__a._M_data, __n, __b._M_data); }
+
+  // Copy strided array __a[<__n : __s>] in plain __b[<__n>]
+  template<typename _Tp>
+    inline void
+    __valarray_copy(_Array<_Tp> __a, size_t __n, size_t __s, _Array<_Tp> __b)
+    { std::__valarray_copy(__a._M_data, __n, __s, __b._M_data); }
+
+  // Copy a plain array  __a[<__n>] into a strided array __b[<__n : __s>]
+  template<typename _Tp>
+    inline void
+    __valarray_copy(_Array<_Tp> __a, _Array<_Tp> __b, size_t __n, size_t __s)
+    { __valarray_copy(__a._M_data, __b._M_data, __n, __s); }
+
+  // Copy strided array __src[<__n : __s1>] into another
+  // strided array __dst[< : __s2>].  Their sizes must match.
+  template<typename _Tp>
+    inline void
+    __valarray_copy(_Array<_Tp> __a, size_t __n, size_t __s1,
+                    _Array<_Tp> __b, size_t __s2)
+    { std::__valarray_copy(__a._M_data, __n, __s1, __b._M_data, __s2); }
+
+  // Copy an indexed array __a[__i[<__n>]] in plain array __b[<__n>]
+  template<typename _Tp>
+    inline void
+    __valarray_copy(_Array<_Tp> __a, _Array<size_t> __i,
+		    _Array<_Tp> __b, size_t __n)
+    { std::__valarray_copy(__a._M_data, __i._M_data, __b._M_data, __n); }
+
+  // Copy a plain array __a[<__n>] in an indexed array __b[__i[<__n>]]
+  template<typename _Tp>
+    inline void
+    __valarray_copy(_Array<_Tp> __a, size_t __n, _Array<_Tp> __b,
+		    _Array<size_t> __i)
+    { std::__valarray_copy(__a._M_data, __n, __b._M_data, __i._M_data); }
+
+  // Copy the __n first elements of an indexed array __src[<__i>] into
+  // another indexed array __dst[<__j>].
+  template<typename _Tp>
+    inline void
+    __valarray_copy(_Array<_Tp> __src, size_t __n, _Array<size_t> __i,
+                    _Array<_Tp> __dst, _Array<size_t> __j)
+    {
+      std::__valarray_copy(__src._M_data, __n, __i._M_data,
+		    __dst._M_data, __j._M_data);
+    }
+
+  template<typename _Tp>
+    inline
+    _Array<_Tp>::_Array(_Tp* const __restrict__ __p)
+    : _M_data (__p) {}
+
+  template<typename _Tp>
+    inline
+    _Array<_Tp>::_Array(const valarray<_Tp>& __v)
+    : _M_data (__v._M_data) {}
+
+  template<typename _Tp>
+    inline
+    _Array<_Tp>::_Array(const _Tp* __restrict__ __b, size_t __s)
+    : _M_data(__valarray_get_storage<_Tp>(__s))
+    { std::__valarray_copy_construct(__b, __s, _M_data); }
+
+  template<typename _Tp>
+    inline _Tp*
+    _Array<_Tp>::begin () const
+    { return _M_data; }
+
+#define _DEFINE_ARRAY_FUNCTION(_Op, _Name)				\
+  template<typename _Tp>		        			\
+    inline void								\
+    _Array_augmented_##_Name(_Array<_Tp> __a, size_t __n, const _Tp& __t) \
+    {									\
+      for (_Tp* __p = __a._M_data; __p < __a._M_data + __n; ++__p)	\
+        *__p _Op##= __t;						\
+    }									\
+									\
+  template<typename _Tp>						\
+    inline void								\
+    _Array_augmented_##_Name(_Array<_Tp> __a, size_t __n, _Array<_Tp> __b) \
+    {									\
+      _Tp* __p = __a._M_data;						\
+      for (_Tp* __q = __b._M_data; __q < __b._M_data + __n; ++__p, ++__q) \
+        *__p _Op##= *__q;						\
+    }									\
+									\
+  template<typename _Tp, class _Dom>					\
+    void								\
+    _Array_augmented_##_Name(_Array<_Tp> __a,	        		\
+                             const _Expr<_Dom, _Tp>& __e, size_t __n)	\
+    {									\
+      _Tp* __p(__a._M_data);						\
+      for (size_t __i = 0; __i < __n; ++__i, ++__p)                     \
+        *__p _Op##= __e[__i];                                          	\
+    }									\
+									\
+  template<typename _Tp>						\
+    inline void								\
+    _Array_augmented_##_Name(_Array<_Tp> __a, size_t __n, size_t __s,	\
+	                     _Array<_Tp> __b)				\
+    {									\
+      _Tp* __q(__b._M_data);						\
+      for (_Tp* __p = __a._M_data; __p < __a._M_data + __s * __n;       \
+	   __p += __s, ++__q)                                           \
+        *__p _Op##= *__q;						\
+    }									\
+									\
+  template<typename _Tp>						\
+    inline void								\
+    _Array_augmented_##_Name(_Array<_Tp> __a, _Array<_Tp> __b,		\
+		             size_t __n, size_t __s)			\
+    {									\
+      _Tp* __q(__b._M_data);						\
+      for (_Tp* __p = __a._M_data; __p < __a._M_data + __n;             \
+	   ++__p, __q += __s)                                           \
+        *__p _Op##= *__q;						\
+    }									\
+									\
+  template<typename _Tp, class _Dom>					\
+    void								\
+    _Array_augmented_##_Name(_Array<_Tp> __a, size_t __s,		\
+                             const _Expr<_Dom, _Tp>& __e, size_t __n)	\
+    {									\
+      _Tp* __p(__a._M_data);						\
+      for (size_t __i = 0; __i < __n; ++__i, __p += __s)                \
+        *__p _Op##= __e[__i];                                          	\
+    }									\
+									\
+  template<typename _Tp>						\
+    inline void								\
+    _Array_augmented_##_Name(_Array<_Tp> __a, _Array<size_t> __i,	\
+                             _Array<_Tp> __b, size_t __n)		\
+    {									\
+      _Tp* __q(__b._M_data);						\
+      for (size_t* __j = __i._M_data; __j < __i._M_data + __n;          \
+           ++__j, ++__q)                                                \
+        __a._M_data[*__j] _Op##= *__q;					\
+    }									\
+									\
+  template<typename _Tp>						\
+    inline void					        		\
+    _Array_augmented_##_Name(_Array<_Tp> __a, size_t __n,		\
+                             _Array<_Tp> __b, _Array<size_t> __i)	\
+    {									\
+      _Tp* __p(__a._M_data);						\
+      for (size_t* __j = __i._M_data; __j<__i._M_data + __n;            \
+	   ++__j, ++__p)                                                \
+        *__p _Op##= __b._M_data[*__j];					\
+    }									\
+									\
+  template<typename _Tp, class _Dom>					\
+    void								\
+    _Array_augmented_##_Name(_Array<_Tp> __a, _Array<size_t> __i,	\
+                             const _Expr<_Dom, _Tp>& __e, size_t __n)	\
+    {									\
+      size_t* __j(__i._M_data);	        				\
+      for (size_t __k = 0; __k<__n; ++__k, ++__j)			\
+        __a._M_data[*__j] _Op##= __e[__k];				\
+    }									\
+									\
+  template<typename _Tp>						\
+    void								\
+    _Array_augmented_##_Name(_Array<_Tp> __a, _Array<bool> __m,         \
+                             _Array<_Tp> __b, size_t __n)		\
+    {									\
+      bool* __ok(__m._M_data);						\
+      _Tp* __p(__a._M_data);						\
+      for (_Tp* __q = __b._M_data; __q < __b._M_data + __n;             \
+	   ++__q, ++__ok, ++__p)                                        \
+        {                                                               \
+          while (! *__ok)                                               \
+            {						        	\
+              ++__ok;							\
+              ++__p;							\
+            }								\
+          *__p _Op##= *__q;						\
+        }								\
+    }									\
+									\
+  template<typename _Tp>						\
+    void								\
+    _Array_augmented_##_Name(_Array<_Tp> __a, size_t __n,		\
+                             _Array<_Tp> __b, _Array<bool> __m)   	\
+    {									\
+      bool* __ok(__m._M_data);						\
+      _Tp* __q(__b._M_data);						\
+      for (_Tp* __p = __a._M_data; __p < __a._M_data + __n;             \
+	   ++__p, ++__ok, ++__q)                                        \
+        {                                                               \
+          while (! *__ok)                                               \
+            {					        		\
+              ++__ok;							\
+              ++__q;							\
+            }								\
+          *__p _Op##= *__q;						\
+        }								\
+    }									\
+									\
+  template<typename _Tp, class _Dom>					\
+    void								\
+    _Array_augmented_##_Name(_Array<_Tp> __a, _Array<bool> __m,  	\
+                             const _Expr<_Dom, _Tp>& __e, size_t __n)	\
+    {									\
+      bool* __ok(__m._M_data);						\
+      _Tp* __p(__a._M_data);						\
+      for (size_t __i = 0; __i < __n; ++__i, ++__ok, ++__p)             \
+        {	                                           		\
+          while (! *__ok)                                               \
+            {		         					\
+	      ++__ok;							\
+              ++__p;							\
+            }								\
+          *__p _Op##= __e[__i];						\
+        }								\
+    }
+
+   _DEFINE_ARRAY_FUNCTION(+, __plus)
+   _DEFINE_ARRAY_FUNCTION(-, __minus)
+   _DEFINE_ARRAY_FUNCTION(*, __multiplies)
+   _DEFINE_ARRAY_FUNCTION(/, __divides)
+   _DEFINE_ARRAY_FUNCTION(%, __modulus)
+   _DEFINE_ARRAY_FUNCTION(^, __bitwise_xor)
+   _DEFINE_ARRAY_FUNCTION(|, __bitwise_or)
+   _DEFINE_ARRAY_FUNCTION(&, __bitwise_and)
+   _DEFINE_ARRAY_FUNCTION(<<, __shift_left)
+   _DEFINE_ARRAY_FUNCTION(>>, __shift_right)
+
+#undef _DEFINE_ARRAY_FUNCTION
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+# include <bits/valarray_array.tcc>
+
+#endif /* _ARRAY_H */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@valarray_array.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@valarray_array.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@valarray_array.tcc b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@valarray_array.tcc
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@valarray_array.tcc
@@ -0,0 +1,244 @@
+// The template and inlines for the -*- C++ -*- internal _Array helper class.
+
+// Copyright (C) 1997-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/valarray_array.tcc
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{valarray}
+ */
+
+// Written by Gabriel Dos Reis <Gabriel.Dos-Reis@DPTMaths.ENS-Cachan.Fr>
+
+#ifndef _VALARRAY_ARRAY_TCC
+#define _VALARRAY_ARRAY_TCC 1
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  template<typename _Tp>
+    void
+    __valarray_fill(_Array<_Tp> __a, size_t __n, _Array<bool> __m,
+		    const _Tp& __t)
+    {
+      _Tp* __p = __a._M_data;
+      bool* __ok (__m._M_data);
+      for (size_t __i=0; __i < __n; ++__i, ++__ok, ++__p)
+	{
+	  while (!*__ok)
+	  {
+	    ++__ok;
+	    ++__p;
+	  }
+	  *__p = __t;
+	}
+    }
+
+  // Copy n elements of a into consecutive elements of b.  When m is
+  // false, the corresponding element of a is skipped.  m must contain
+  // at least n true elements.  a must contain at least n elements and
+  // enough elements to match up with m through the nth true element
+  // of m.  I.e.  if n is 10, m has 15 elements with 5 false followed
+  // by 10 true, a must have 15 elements.
+  template<typename _Tp>
+    void
+    __valarray_copy(_Array<_Tp> __a, _Array<bool> __m, _Array<_Tp> __b,
+		    size_t __n)
+    {
+      _Tp* __p (__a._M_data);
+      bool* __ok (__m._M_data);
+      for (_Tp* __q = __b._M_data; __q < __b._M_data + __n;
+	   ++__q, ++__ok, ++__p)
+	{
+	  while (! *__ok)
+	    {
+	      ++__ok;
+	      ++__p;
+	    }
+	  *__q = *__p;
+	}
+    }
+
+  // Copy n consecutive elements from a into elements of b.  Elements
+  // of b are skipped if the corresponding element of m is false.  m
+  // must contain at least n true elements.  b must have at least as
+  // many elements as the index of the nth true element of m.  I.e. if
+  // m has 15 elements with 5 false followed by 10 true, b must have
+  // at least 15 elements.
+  template<typename _Tp>
+    void
+    __valarray_copy(_Array<_Tp> __a, size_t __n, _Array<_Tp> __b,
+		    _Array<bool> __m)
+    {
+      _Tp* __q (__b._M_data);
+      bool* __ok (__m._M_data);
+      for (_Tp* __p = __a._M_data; __p < __a._M_data+__n;
+	   ++__p, ++__ok, ++__q)
+	{
+	  while (! *__ok)
+	    {
+	      ++__ok;
+	      ++__q;
+	    }
+	  *__q = *__p;
+	}
+    }
+
+  // Copy n elements from a into elements of b.  Elements of a are
+  // skipped if the corresponding element of m is false.  Elements of
+  // b are skipped if the corresponding element of k is false.  m and
+  // k must contain at least n true elements.  a and b must have at
+  // least as many elements as the index of the nth true element of m.
+  template<typename _Tp>
+    void
+    __valarray_copy(_Array<_Tp> __a, _Array<bool> __m, size_t __n,
+		    _Array<_Tp> __b, _Array<bool> __k)
+    {
+      _Tp* __p (__a._M_data);
+      _Tp* __q (__b._M_data);
+      bool* __srcok (__m._M_data);
+      bool* __dstok (__k._M_data);
+      for (size_t __i = 0; __i < __n;
+	   ++__srcok, ++__p, ++__dstok, ++__q, ++__i)
+	{
+	  while (! *__srcok)
+	    {
+	      ++__srcok;
+	      ++__p;
+	    }
+	  while (! *__dstok) 
+	    {
+	      ++__dstok;
+	      ++__q;
+	    }
+	  *__q = *__p;
+	}
+    }
+
+  // Copy n consecutive elements of e into consecutive elements of a.
+  // I.e. a[i] = e[i].
+  template<typename _Tp, class _Dom>
+    void
+    __valarray_copy(const _Expr<_Dom, _Tp>& __e, size_t __n, _Array<_Tp> __a)
+    {
+      _Tp* __p (__a._M_data);
+      for (size_t __i = 0; __i < __n; ++__i, ++__p)
+	*__p = __e[__i];
+    }
+
+  // Copy n consecutive elements of e into elements of a using stride
+  // s.  I.e., a[0] = e[0], a[s] = e[1], a[2*s] = e[2].
+  template<typename _Tp, class _Dom>
+    void
+    __valarray_copy(const _Expr<_Dom, _Tp>& __e, size_t __n,
+		     _Array<_Tp> __a, size_t __s)
+    {
+      _Tp* __p (__a._M_data);
+      for (size_t __i = 0; __i < __n; ++__i, __p += __s)
+	*__p = __e[__i];
+    }
+
+  // Copy n consecutive elements of e into elements of a indexed by
+  // contents of i.  I.e., a[i[0]] = e[0].
+  template<typename _Tp, class _Dom>
+    void
+    __valarray_copy(const _Expr<_Dom, _Tp>& __e, size_t __n,
+		    _Array<_Tp> __a, _Array<size_t> __i)
+    {
+      size_t* __j (__i._M_data);
+      for (size_t __k = 0; __k < __n; ++__k, ++__j)
+	__a._M_data[*__j] = __e[__k];
+    }
+
+  // Copy n elements of e indexed by contents of f into elements of a
+  // indexed by contents of i.  I.e., a[i[0]] = e[f[0]].
+  template<typename _Tp>
+    void
+    __valarray_copy(_Array<_Tp> __e, _Array<size_t> __f,
+		    size_t __n, 
+		    _Array<_Tp> __a, _Array<size_t> __i)
+    {
+      size_t* __g (__f._M_data);
+      size_t* __j (__i._M_data);
+      for (size_t __k = 0; __k < __n; ++__k, ++__j, ++__g) 
+	__a._M_data[*__j] = __e._M_data[*__g];
+    }
+
+  // Copy n consecutive elements of e into elements of a.  Elements of
+  // a are skipped if the corresponding element of m is false.  m must
+  // have at least n true elements and a must have at least as many
+  // elements as the index of the nth true element of m.  I.e. if m
+  // has 5 false followed by 10 true elements and n == 10, a must have
+  // at least 15 elements.
+  template<typename _Tp, class _Dom>
+    void
+    __valarray_copy(const _Expr<_Dom, _Tp>& __e, size_t __n,
+		    _Array<_Tp> __a, _Array<bool> __m)
+    {
+      bool* __ok (__m._M_data);
+      _Tp* __p (__a._M_data);
+      for (size_t __i = 0; __i < __n; ++__i, ++__ok, ++__p)
+	{
+	  while (! *__ok)
+	    {
+	      ++__ok;
+	      ++__p;
+	    }
+	  *__p = __e[__i];
+	}
+    }
+
+
+  template<typename _Tp, class _Dom>
+    void
+    __valarray_copy_construct(const _Expr<_Dom, _Tp>& __e, size_t __n,
+			      _Array<_Tp> __a)
+    {
+      _Tp* __p (__a._M_data);
+      for (size_t __i = 0; __i < __n; ++__i, ++__p)
+	new (__p) _Tp(__e[__i]);
+    }
+
+
+  template<typename _Tp>
+    void
+    __valarray_copy_construct(_Array<_Tp> __a, _Array<bool> __m,
+			      _Array<_Tp> __b, size_t __n)
+    {
+      _Tp* __p (__a._M_data);
+      bool* __ok (__m._M_data);
+      for (_Tp* __q = __b._M_data; __q < __b._M_data+__n; ++__q, ++__ok, ++__p)
+	{
+	  while (! *__ok)
+	    {
+	      ++__ok;
+	      ++__p;
+	    }
+	  new (__q) _Tp(*__p);
+	}
+    }
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif /* _VALARRAY_ARRAY_TCC */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@valarray_array.tcc.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@valarray_array.tcc.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@valarray_before.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@valarray_before.h
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index 0000000000000000000000000000000000000000..401d4f70830f8de7a54a06b46bafbd3c88fdb6e1
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@valarray_before.h
@@ -0,0 +1,758 @@
+// The template and inlines for the -*- C++ -*- internal _Meta class.
+
+// Copyright (C) 1997-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/valarray_before.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{valarray}
+ */
+
+// Written by Gabriel Dos Reis <Gabriel.Dos-Reis@cmla.ens-cachan.fr>
+
+#ifndef _VALARRAY_BEFORE_H
+#define _VALARRAY_BEFORE_H 1
+
+#pragma GCC system_header
+
+#include <bits/slice_array.h>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  //
+  // Implementing a loosened valarray return value is tricky.
+  // First we need to meet 26.3.1/3: we should not add more than
+  // two levels of template nesting. Therefore we resort to template
+  // template to "flatten" loosened return value types.
+  // At some point we use partial specialization to remove one level
+  // template nesting due to _Expr<>
+  //
+
+  // This class is NOT defined. It doesn't need to.
+  template<typename _Tp1, typename _Tp2> class _Constant;
+
+  // Implementations of unary functions applied to valarray<>s.
+  // I use hard-coded object functions here instead of a generic
+  // approach like pointers to function:
+  //    1) correctness: some functions take references, others values.
+  //       we can't deduce the correct type afterwards.
+  //    2) efficiency -- object functions can be easily inlined
+  //    3) be Koenig-lookup-friendly
+
+  struct _Abs
+  {
+    template<typename _Tp>
+      _Tp operator()(const _Tp& __t) const
+      { return abs(__t); }
+  };
+
+  struct _Cos
+  {
+    template<typename _Tp>
+      _Tp operator()(const _Tp& __t) const
+      { return cos(__t); }
+  };
+
+  struct _Acos
+  {
+    template<typename _Tp>
+      _Tp operator()(const _Tp& __t) const
+      { return acos(__t); }
+  };
+
+  struct _Cosh
+  {
+    template<typename _Tp>
+      _Tp operator()(const _Tp& __t) const
+      { return cosh(__t); }
+  };
+
+  struct _Sin
+  {
+    template<typename _Tp>
+      _Tp operator()(const _Tp& __t) const
+      { return sin(__t); }
+  };
+
+  struct _Asin
+  {
+    template<typename _Tp>
+      _Tp operator()(const _Tp& __t) const
+      { return asin(__t); }
+  };
+
+  struct _Sinh
+  {
+    template<typename _Tp>
+      _Tp operator()(const _Tp& __t) const
+      { return sinh(__t); }
+  };
+
+  struct _Tan
+  {
+    template<typename _Tp>
+      _Tp operator()(const _Tp& __t) const
+      { return tan(__t); }
+  };
+
+  struct _Atan
+  {
+    template<typename _Tp>
+      _Tp operator()(const _Tp& __t) const
+      { return atan(__t); }
+  };
+
+  struct _Tanh
+  {
+    template<typename _Tp>
+      _Tp operator()(const _Tp& __t) const
+      { return tanh(__t); }
+  };
+
+  struct _Exp
+  {
+    template<typename _Tp>
+      _Tp operator()(const _Tp& __t) const
+      { return exp(__t); }
+  };
+
+  struct _Log
+  {
+    template<typename _Tp>
+      _Tp operator()(const _Tp& __t) const
+      { return log(__t); }
+  };
+
+  struct _Log10
+  {
+    template<typename _Tp>
+      _Tp operator()(const _Tp& __t) const
+      { return log10(__t); }
+  };
+
+  struct _Sqrt
+  {
+    template<typename _Tp>
+      _Tp operator()(const _Tp& __t) const
+      { return sqrt(__t); }
+  };
+
+  // In the past, we used to tailor operator applications semantics
+  // to the specialization of standard function objects (i.e. plus<>, etc.)
+  // That is incorrect.  Therefore we provide our own surrogates.
+
+  struct __unary_plus
+  {
+    template<typename _Tp>
+      _Tp operator()(const _Tp& __t) const
+      { return +__t; }
+  };
+
+  struct __negate
+  {
+    template<typename _Tp>
+      _Tp operator()(const _Tp& __t) const
+      { return -__t; }
+  };
+
+  struct __bitwise_not
+  {
+    template<typename _Tp>
+      _Tp operator()(const _Tp& __t) const
+      { return ~__t; }
+  };
+
+  struct __plus
+  {
+    template<typename _Tp>
+      _Tp operator()(const _Tp& __x, const _Tp& __y) const
+      { return __x + __y; }
+  };
+
+  struct __minus
+  {
+    template<typename _Tp>
+      _Tp operator()(const _Tp& __x, const _Tp& __y) const
+      { return __x - __y; }
+  };
+
+  struct __multiplies
+  {
+    template<typename _Tp>
+      _Tp operator()(const _Tp& __x, const _Tp& __y) const
+      { return __x * __y; }
+  };
+
+  struct __divides
+  {
+    template<typename _Tp>
+      _Tp operator()(const _Tp& __x, const _Tp& __y) const
+      { return __x / __y; }
+  };
+
+  struct __modulus
+  {
+    template<typename _Tp>
+      _Tp operator()(const _Tp& __x, const _Tp& __y) const
+      { return __x % __y; }
+  };
+
+  struct __bitwise_xor
+  {
+    template<typename _Tp>
+      _Tp operator()(const _Tp& __x, const _Tp& __y) const
+      { return __x ^ __y; }
+  };
+
+  struct __bitwise_and
+  {
+    template<typename _Tp>
+      _Tp operator()(const _Tp& __x, const _Tp& __y) const
+      { return __x & __y; }
+  };
+
+  struct __bitwise_or
+  {
+    template<typename _Tp>
+      _Tp operator()(const _Tp& __x, const _Tp& __y) const
+      { return __x | __y; }
+  };
+
+  struct __shift_left
+  {
+    template<typename _Tp>
+      _Tp operator()(const _Tp& __x, const _Tp& __y) const
+      { return __x << __y; }
+  };
+
+  struct __shift_right
+  {
+    template<typename _Tp>
+      _Tp operator()(const _Tp& __x, const _Tp& __y) const
+      { return __x >> __y; }
+  };
+
+  struct __logical_and
+  {
+    template<typename _Tp>
+      bool operator()(const _Tp& __x, const _Tp& __y) const
+      { return __x && __y; }
+  };
+
+  struct __logical_or
+  {
+    template<typename _Tp>
+      bool operator()(const _Tp& __x, const _Tp& __y) const
+      { return __x || __y; }
+  };
+
+  struct __logical_not
+  {
+    template<typename _Tp>
+      bool operator()(const _Tp& __x) const
+      { return !__x; }
+  };
+
+  struct __equal_to
+  {
+    template<typename _Tp>
+      bool operator()(const _Tp& __x, const _Tp& __y) const
+      { return __x == __y; }
+  };
+
+  struct __not_equal_to
+  {
+    template<typename _Tp>
+      bool operator()(const _Tp& __x, const _Tp& __y) const
+      { return __x != __y; }
+  };
+
+  struct __less
+  {
+    template<typename _Tp>
+      bool operator()(const _Tp& __x, const _Tp& __y) const
+      { return __x < __y; }
+  };
+
+  struct __greater
+  {
+    template<typename _Tp>
+      bool operator()(const _Tp& __x, const _Tp& __y) const
+      { return __x > __y; }
+  };
+
+  struct __less_equal
+  {
+    template<typename _Tp>
+      bool operator()(const _Tp& __x, const _Tp& __y) const
+      { return __x <= __y; }
+  };
+
+  struct __greater_equal
+  {
+    template<typename _Tp>
+      bool operator()(const _Tp& __x, const _Tp& __y) const
+      { return __x >= __y; }
+  };
+
+  // The few binary functions we miss.
+  struct _Atan2
+  {
+    template<typename _Tp>
+      _Tp operator()(const _Tp& __x, const _Tp& __y) const
+      { return atan2(__x, __y); }
+  };
+
+  struct _Pow
+  {
+    template<typename _Tp>
+      _Tp operator()(const _Tp& __x, const _Tp& __y) const
+      { return pow(__x, __y); }
+  };
+
+  template<typename _Tp, bool _IsValidValarrayValue = !__is_abstract(_Tp)>
+    struct __fun_with_valarray
+    {
+      typedef _Tp result_type;
+    };
+
+  template<typename _Tp>
+    struct __fun_with_valarray<_Tp, false>
+    {
+      // No result type defined for invalid value types.
+    };
+
+  // We need these bits in order to recover the return type of
+  // some functions/operators now that we're no longer using
+  // function templates.
+  template<typename, typename _Tp>
+    struct __fun : __fun_with_valarray<_Tp>
+    {
+    };
+
+  // several specializations for relational operators.
+  template<typename _Tp>
+    struct __fun<__logical_not, _Tp>
+    {
+      typedef bool result_type;
+    };
+
+  template<typename _Tp>
+    struct __fun<__logical_and, _Tp>
+    {
+      typedef bool result_type;
+    };
+
+  template<typename _Tp>
+    struct __fun<__logical_or, _Tp>
+    {
+      typedef bool result_type;
+    };
+
+  template<typename _Tp>
+    struct __fun<__less, _Tp>
+    {
+      typedef bool result_type;
+    };
+
+  template<typename _Tp>
+    struct __fun<__greater, _Tp>
+    {
+      typedef bool result_type;
+    };
+
+  template<typename _Tp>
+    struct __fun<__less_equal, _Tp>
+    {
+      typedef bool result_type;
+    };
+
+  template<typename _Tp>
+    struct __fun<__greater_equal, _Tp>
+    {
+      typedef bool result_type;
+    };
+
+  template<typename _Tp>
+    struct __fun<__equal_to, _Tp>
+    {
+      typedef bool result_type;
+    };
+
+  template<typename _Tp>
+    struct __fun<__not_equal_to, _Tp>
+    {
+      typedef bool result_type;
+    };
+
+namespace __detail
+{
+  // Closure types already have reference semantics and are often short-lived,
+  // so store them by value to avoid (some cases of) dangling references to
+  // out-of-scope temporaries.
+  template<typename _Tp>
+    struct _ValArrayRef
+    { typedef const _Tp __type; };
+
+  // Use real references for std::valarray objects.
+  template<typename _Tp>
+    struct _ValArrayRef< valarray<_Tp> >
+    { typedef const valarray<_Tp>& __type; };
+
+  //
+  // Apply function taking a value/const reference closure
+  //
+
+  template<typename _Dom, typename _Arg>
+    class _FunBase
+    {
+    public:
+      typedef typename _Dom::value_type value_type;
+
+      _FunBase(const _Dom& __e, value_type __f(_Arg))
+      : _M_expr(__e), _M_func(__f) {}
+
+      value_type operator[](size_t __i) const
+      { return _M_func (_M_expr[__i]); }
+
+      size_t size() const { return _M_expr.size ();}
+
+    private:
+      typename _ValArrayRef<_Dom>::__type _M_expr;
+      value_type (*_M_func)(_Arg);
+    };
+
+  template<class _Dom>
+    struct _ValFunClos<_Expr,_Dom> : _FunBase<_Dom, typename _Dom::value_type>
+    {
+      typedef _FunBase<_Dom, typename _Dom::value_type> _Base;
+      typedef typename _Base::value_type value_type;
+      typedef value_type _Tp;
+
+      _ValFunClos(const _Dom& __e, _Tp __f(_Tp)) : _Base(__e, __f) {}
+    };
+
+  template<typename _Tp>
+    struct _ValFunClos<_ValArray,_Tp> : _FunBase<valarray<_Tp>, _Tp>
+    {
+      typedef _FunBase<valarray<_Tp>, _Tp> _Base;
+      typedef _Tp value_type;
+
+      _ValFunClos(const valarray<_Tp>& __v, _Tp __f(_Tp)) : _Base(__v, __f) {}
+    };
+
+  template<class _Dom>
+    struct _RefFunClos<_Expr, _Dom>
+    : _FunBase<_Dom, const typename _Dom::value_type&>
+    {
+      typedef _FunBase<_Dom, const typename _Dom::value_type&> _Base;
+      typedef typename _Base::value_type value_type;
+      typedef value_type _Tp;
+
+      _RefFunClos(const _Dom& __e, _Tp __f(const _Tp&))
+      : _Base(__e, __f) {}
+    };
+
+  template<typename _Tp>
+    struct _RefFunClos<_ValArray, _Tp>
+    : _FunBase<valarray<_Tp>, const _Tp&>
+    {
+      typedef _FunBase<valarray<_Tp>, const _Tp&> _Base;
+      typedef _Tp value_type;
+
+      _RefFunClos(const valarray<_Tp>& __v, _Tp __f(const _Tp&))
+      : _Base(__v, __f) {}
+    };
+
+  //
+  // Unary expression closure.
+  //
+
+  template<class _Oper, class _Arg>
+    class _UnBase
+    {
+    public:
+      typedef typename _Arg::value_type _Vt;
+      typedef typename __fun<_Oper, _Vt>::result_type value_type;
+
+      _UnBase(const _Arg& __e) : _M_expr(__e) {}
+
+      value_type operator[](size_t __i) const
+      { return _Oper()(_M_expr[__i]); }
+
+      size_t size() const { return _M_expr.size(); }
+      
+    private:
+      typename _ValArrayRef<_Arg>::__type _M_expr;
+    };
+
+  template<class _Oper, class _Dom>
+    struct _UnClos<_Oper, _Expr, _Dom>
+    : _UnBase<_Oper, _Dom>
+    {
+      typedef _Dom _Arg;
+      typedef _UnBase<_Oper, _Dom> _Base;
+      typedef typename _Base::value_type value_type;
+
+      _UnClos(const _Arg& __e) : _Base(__e) {}
+    };
+
+  template<class _Oper, typename _Tp>
+    struct _UnClos<_Oper, _ValArray, _Tp>
+    : _UnBase<_Oper, valarray<_Tp> >
+    {
+      typedef valarray<_Tp> _Arg;
+      typedef _UnBase<_Oper, valarray<_Tp> > _Base;
+      typedef typename _Base::value_type value_type;
+
+      _UnClos(const _Arg& __e) : _Base(__e) {}
+    };
+
+
+  //
+  // Binary expression closure.
+  //
+
+  template<class _Oper, class _FirstArg, class _SecondArg>
+    class _BinBase
+    {
+    public:
+      typedef typename _FirstArg::value_type _Vt;
+      typedef typename __fun<_Oper, _Vt>::result_type value_type;
+
+      _BinBase(const _FirstArg& __e1, const _SecondArg& __e2)
+      : _M_expr1(__e1), _M_expr2(__e2) {}
+
+      value_type operator[](size_t __i) const
+      { return _Oper()(_M_expr1[__i], _M_expr2[__i]); }
+
+      size_t size() const { return _M_expr1.size(); }
+
+    private:
+      typename _ValArrayRef<_FirstArg>::__type _M_expr1;
+      typename _ValArrayRef<_SecondArg>::__type _M_expr2;
+    };
+
+
+  template<class _Oper, class _Clos>
+    class _BinBase2
+    {
+    public:
+      typedef typename _Clos::value_type _Vt;
+      typedef typename __fun<_Oper, _Vt>::result_type value_type;
+
+      _BinBase2(const _Clos& __e, const _Vt& __t)
+      : _M_expr1(__e), _M_expr2(__t) {}
+
+      value_type operator[](size_t __i) const
+      { return _Oper()(_M_expr1[__i], _M_expr2); }
+
+      size_t size() const { return _M_expr1.size(); }
+
+    private:
+      typename _ValArrayRef<_Clos>::__type _M_expr1;
+      _Vt _M_expr2;
+    };
+
+  template<class _Oper, class _Clos>
+    class _BinBase1
+    {
+    public:
+      typedef typename _Clos::value_type _Vt;
+      typedef typename __fun<_Oper, _Vt>::result_type value_type;
+
+      _BinBase1(const _Vt& __t, const _Clos& __e)
+      : _M_expr1(__t), _M_expr2(__e) {}
+
+      value_type operator[](size_t __i) const
+      { return _Oper()(_M_expr1, _M_expr2[__i]); }
+
+      size_t size() const { return _M_expr2.size(); }
+
+    private:
+      _Vt _M_expr1;
+      typename _ValArrayRef<_Clos>::__type _M_expr2;
+    };
+
+  template<class _Oper, class _Dom1, class _Dom2>
+    struct _BinClos<_Oper, _Expr, _Expr, _Dom1, _Dom2>
+    : _BinBase<_Oper, _Dom1, _Dom2>
+    {
+      typedef _BinBase<_Oper, _Dom1, _Dom2> _Base;
+      typedef typename _Base::value_type value_type;
+
+      _BinClos(const _Dom1& __e1, const _Dom2& __e2) : _Base(__e1, __e2) {}
+    };
+
+  template<class _Oper, typename _Tp>
+    struct _BinClos<_Oper, _ValArray, _ValArray, _Tp, _Tp>
+    : _BinBase<_Oper, valarray<_Tp>, valarray<_Tp> >
+    {
+      typedef _BinBase<_Oper, valarray<_Tp>, valarray<_Tp> > _Base;
+      typedef typename _Base::value_type value_type;
+
+      _BinClos(const valarray<_Tp>& __v, const valarray<_Tp>& __w)
+      : _Base(__v, __w) {}
+    };
+
+  template<class _Oper, class _Dom>
+    struct _BinClos<_Oper, _Expr, _ValArray, _Dom, typename _Dom::value_type>
+    : _BinBase<_Oper, _Dom, valarray<typename _Dom::value_type> >
+    {
+      typedef typename _Dom::value_type _Tp;
+      typedef _BinBase<_Oper,_Dom,valarray<_Tp> > _Base;
+      typedef typename _Base::value_type value_type;
+
+      _BinClos(const _Dom& __e1, const valarray<_Tp>& __e2)
+      : _Base(__e1, __e2) {}
+    };
+
+  template<class _Oper, class _Dom>
+    struct _BinClos<_Oper, _ValArray, _Expr, typename _Dom::value_type, _Dom>
+    : _BinBase<_Oper, valarray<typename _Dom::value_type>,_Dom>
+    {
+      typedef typename _Dom::value_type _Tp;
+      typedef _BinBase<_Oper, valarray<_Tp>, _Dom> _Base;
+      typedef typename _Base::value_type value_type;
+
+      _BinClos(const valarray<_Tp>& __e1, const _Dom& __e2)
+      : _Base(__e1, __e2) {}
+    };
+
+  template<class _Oper, class _Dom>
+    struct _BinClos<_Oper, _Expr, _Constant, _Dom, typename _Dom::value_type>
+    : _BinBase2<_Oper, _Dom>
+    {
+      typedef typename _Dom::value_type _Tp;
+      typedef _BinBase2<_Oper,_Dom> _Base;
+      typedef typename _Base::value_type value_type;
+
+      _BinClos(const _Dom& __e1, const _Tp& __e2) : _Base(__e1, __e2) {}
+    };
+
+  template<class _Oper, class _Dom>
+    struct _BinClos<_Oper, _Constant, _Expr, typename _Dom::value_type, _Dom>
+    : _BinBase1<_Oper, _Dom>
+    {
+      typedef typename _Dom::value_type _Tp;
+      typedef _BinBase1<_Oper, _Dom> _Base;
+      typedef typename _Base::value_type value_type;
+
+      _BinClos(const _Tp& __e1, const _Dom& __e2) : _Base(__e1, __e2) {}
+    };
+
+  template<class _Oper, typename _Tp>
+    struct _BinClos<_Oper, _ValArray, _Constant, _Tp, _Tp>
+    : _BinBase2<_Oper, valarray<_Tp> >
+    {
+      typedef _BinBase2<_Oper,valarray<_Tp> > _Base;
+      typedef typename _Base::value_type value_type;
+
+      _BinClos(const valarray<_Tp>& __v, const _Tp& __t) : _Base(__v, __t) {}
+    };
+
+  template<class _Oper, typename _Tp>
+    struct _BinClos<_Oper, _Constant, _ValArray, _Tp, _Tp>
+    : _BinBase1<_Oper, valarray<_Tp> >
+    {
+      typedef _BinBase1<_Oper, valarray<_Tp> > _Base;
+      typedef typename _Base::value_type value_type;
+
+      _BinClos(const _Tp& __t, const valarray<_Tp>& __v) : _Base(__t, __v) {}
+    };
+
+  //
+  // slice_array closure.
+  //
+  template<typename _Dom>
+    class _SBase
+    {
+    public:
+      typedef typename _Dom::value_type value_type;
+      
+      _SBase (const _Dom& __e, const slice& __s)
+      : _M_expr (__e), _M_slice (__s) {}
+        
+      value_type
+      operator[] (size_t __i) const
+      { return _M_expr[_M_slice.start () + __i * _M_slice.stride ()]; }
+        
+      size_t
+      size() const
+      { return _M_slice.size (); }
+
+    private:
+      typename _ValArrayRef<_Dom>::__type _M_expr;
+      const slice& _M_slice;
+    };
+
+  template<typename _Tp>
+    class _SBase<_Array<_Tp> >
+    {
+    public:
+      typedef _Tp value_type;
+      
+      _SBase (_Array<_Tp> __a, const slice& __s)
+      : _M_array (__a._M_data+__s.start()), _M_size (__s.size()),
+	_M_stride (__s.stride()) {}
+        
+      value_type
+      operator[] (size_t __i) const
+      { return _M_array._M_data[__i * _M_stride]; }
+      
+      size_t
+      size() const
+      { return _M_size; }
+
+    private:
+      const _Array<_Tp> _M_array;
+      const size_t _M_size;
+      const size_t _M_stride;
+    };
+
+  template<class _Dom>
+    struct _SClos<_Expr, _Dom>
+    : _SBase<_Dom>
+    {
+      typedef _SBase<_Dom> _Base;
+      typedef typename _Base::value_type value_type;
+      
+      _SClos (const _Dom& __e, const slice& __s) : _Base (__e, __s) {}
+    };
+
+  template<typename _Tp>
+    struct _SClos<_ValArray, _Tp>
+    : _SBase<_Array<_Tp> >
+    {
+      typedef  _SBase<_Array<_Tp> > _Base;
+      typedef _Tp value_type;
+      
+      _SClos (_Array<_Tp> __a, const slice& __s) : _Base (__a, __s) {}
+    };
+} // namespace __detail
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif /* _CPP_VALARRAY_BEFORE_H */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@valarray_before.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@valarray_before.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@vector.tcc b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@vector.tcc
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@vector.tcc
@@ -0,0 +1,1036 @@
+// Vector implementation (out of line) -*- C++ -*-
+
+// Copyright (C) 2001-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/*
+ *
+ * Copyright (c) 1994
+ * Hewlett-Packard Company
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Hewlett-Packard Company makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ *
+ *
+ * Copyright (c) 1996
+ * Silicon Graphics Computer Systems, Inc.
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Silicon Graphics makes no
+ * representations about the suitability of this  software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ */
+
+/** @file bits/vector.tcc
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{vector}
+ */
+
+#ifndef _VECTOR_TCC
+#define _VECTOR_TCC 1
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+_GLIBCXX_BEGIN_NAMESPACE_CONTAINER
+
+  template<typename _Tp, typename _Alloc>
+    _GLIBCXX20_CONSTEXPR
+    void
+    vector<_Tp, _Alloc>::
+    reserve(size_type __n)
+    {
+      if (__n > this->max_size())
+	__throw_length_error(__N("vector::reserve"));
+      if (this->capacity() < __n)
+	{
+	  const size_type __old_size = size();
+	  pointer __tmp;
+#if __cplusplus >= 201103L
+	  if _GLIBCXX17_CONSTEXPR (_S_use_relocate())
+	    {
+	      __tmp = this->_M_allocate(__n);
+	      _S_relocate(this->_M_impl._M_start, this->_M_impl._M_finish,
+			  __tmp, _M_get_Tp_allocator());
+	    }
+	  else
+#endif
+	    {
+	      __tmp = _M_allocate_and_copy(__n,
+		_GLIBCXX_MAKE_MOVE_IF_NOEXCEPT_ITERATOR(this->_M_impl._M_start),
+		_GLIBCXX_MAKE_MOVE_IF_NOEXCEPT_ITERATOR(this->_M_impl._M_finish));
+	      std::_Destroy(this->_M_impl._M_start, this->_M_impl._M_finish,
+			    _M_get_Tp_allocator());
+	    }
+	  _GLIBCXX_ASAN_ANNOTATE_REINIT;
+	  _M_deallocate(this->_M_impl._M_start,
+			this->_M_impl._M_end_of_storage
+			- this->_M_impl._M_start);
+	  this->_M_impl._M_start = __tmp;
+	  this->_M_impl._M_finish = __tmp + __old_size;
+	  this->_M_impl._M_end_of_storage = this->_M_impl._M_start + __n;
+	}
+    }
+
+#if __cplusplus >= 201103L
+  template<typename _Tp, typename _Alloc>
+    template<typename... _Args>
+#if __cplusplus > 201402L
+      _GLIBCXX20_CONSTEXPR
+      typename vector<_Tp, _Alloc>::reference
+#else
+      void
+#endif
+      vector<_Tp, _Alloc>::
+      emplace_back(_Args&&... __args)
+      {
+	if (this->_M_impl._M_finish != this->_M_impl._M_end_of_storage)
+	  {
+	    _GLIBCXX_ASAN_ANNOTATE_GROW(1);
+	    _Alloc_traits::construct(this->_M_impl, this->_M_impl._M_finish,
+				     std::forward<_Args>(__args)...);
+	    ++this->_M_impl._M_finish;
+	    _GLIBCXX_ASAN_ANNOTATE_GREW(1);
+	  }
+	else
+	  _M_realloc_insert(end(), std::forward<_Args>(__args)...);
+#if __cplusplus > 201402L
+	return back();
+#endif
+      }
+#endif
+
+  template<typename _Tp, typename _Alloc>
+    _GLIBCXX20_CONSTEXPR
+    typename vector<_Tp, _Alloc>::iterator
+    vector<_Tp, _Alloc>::
+#if __cplusplus >= 201103L
+    insert(const_iterator __position, const value_type& __x)
+#else
+    insert(iterator __position, const value_type& __x)
+#endif
+    {
+      const size_type __n = __position - begin();
+      if (this->_M_impl._M_finish != this->_M_impl._M_end_of_storage)
+	if (__position == end())
+	  {
+	    _GLIBCXX_ASAN_ANNOTATE_GROW(1);
+	    _Alloc_traits::construct(this->_M_impl, this->_M_impl._M_finish,
+				     __x);
+	    ++this->_M_impl._M_finish;
+	    _GLIBCXX_ASAN_ANNOTATE_GREW(1);
+	  }
+	else
+	  {
+#if __cplusplus >= 201103L
+	    const auto __pos = begin() + (__position - cbegin());
+	    // __x could be an existing element of this vector, so make a
+	    // copy of it before _M_insert_aux moves elements around.
+	    _Temporary_value __x_copy(this, __x);
+	    _M_insert_aux(__pos, std::move(__x_copy._M_val()));
+#else
+	    _M_insert_aux(__position, __x);
+#endif
+	  }
+      else
+#if __cplusplus >= 201103L
+	_M_realloc_insert(begin() + (__position - cbegin()), __x);
+#else
+	_M_realloc_insert(__position, __x);
+#endif
+
+      return iterator(this->_M_impl._M_start + __n);
+    }
+
+  template<typename _Tp, typename _Alloc>
+    _GLIBCXX20_CONSTEXPR
+    typename vector<_Tp, _Alloc>::iterator
+    vector<_Tp, _Alloc>::
+    _M_erase(iterator __position)
+    {
+      if (__position + 1 != end())
+	_GLIBCXX_MOVE3(__position + 1, end(), __position);
+      --this->_M_impl._M_finish;
+      _Alloc_traits::destroy(this->_M_impl, this->_M_impl._M_finish);
+      _GLIBCXX_ASAN_ANNOTATE_SHRINK(1);
+      return __position;
+    }
+
+  template<typename _Tp, typename _Alloc>
+    _GLIBCXX20_CONSTEXPR
+    typename vector<_Tp, _Alloc>::iterator
+    vector<_Tp, _Alloc>::
+    _M_erase(iterator __first, iterator __last)
+    {
+      if (__first != __last)
+	{
+	  if (__last != end())
+	    _GLIBCXX_MOVE3(__last, end(), __first);
+	  _M_erase_at_end(__first.base() + (end() - __last));
+	}
+      return __first;
+    }
+
+  template<typename _Tp, typename _Alloc>
+    _GLIBCXX20_CONSTEXPR
+    vector<_Tp, _Alloc>&
+    vector<_Tp, _Alloc>::
+    operator=(const vector<_Tp, _Alloc>& __x)
+    {
+      if (std::__addressof(__x) != this)
+	{
+	  _GLIBCXX_ASAN_ANNOTATE_REINIT;
+#if __cplusplus >= 201103L
+	  if (_Alloc_traits::_S_propagate_on_copy_assign())
+	    {
+	      if (!_Alloc_traits::_S_always_equal()
+	          && _M_get_Tp_allocator() != __x._M_get_Tp_allocator())
+	        {
+		  // replacement allocator cannot free existing storage
+		  this->clear();
+		  _M_deallocate(this->_M_impl._M_start,
+				this->_M_impl._M_end_of_storage
+				- this->_M_impl._M_start);
+		  this->_M_impl._M_start = nullptr;
+		  this->_M_impl._M_finish = nullptr;
+		  this->_M_impl._M_end_of_storage = nullptr;
+		}
+	      std::__alloc_on_copy(_M_get_Tp_allocator(),
+				   __x._M_get_Tp_allocator());
+	    }
+#endif
+	  const size_type __xlen = __x.size();
+	  if (__xlen > capacity())
+	    {
+	      pointer __tmp = _M_allocate_and_copy(__xlen, __x.begin(),
+						   __x.end());
+	      std::_Destroy(this->_M_impl._M_start, this->_M_impl._M_finish,
+			    _M_get_Tp_allocator());
+	      _M_deallocate(this->_M_impl._M_start,
+			    this->_M_impl._M_end_of_storage
+			    - this->_M_impl._M_start);
+	      this->_M_impl._M_start = __tmp;
+	      this->_M_impl._M_end_of_storage = this->_M_impl._M_start + __xlen;
+	    }
+	  else if (size() >= __xlen)
+	    {
+	      std::_Destroy(std::copy(__x.begin(), __x.end(), begin()),
+			    end(), _M_get_Tp_allocator());
+	    }
+	  else
+	    {
+	      std::copy(__x._M_impl._M_start, __x._M_impl._M_start + size(),
+			this->_M_impl._M_start);
+	      std::__uninitialized_copy_a(__x._M_impl._M_start + size(),
+					  __x._M_impl._M_finish,
+					  this->_M_impl._M_finish,
+					  _M_get_Tp_allocator());
+	    }
+	  this->_M_impl._M_finish = this->_M_impl._M_start + __xlen;
+	}
+      return *this;
+    }
+
+  template<typename _Tp, typename _Alloc>
+    _GLIBCXX20_CONSTEXPR
+    void
+    vector<_Tp, _Alloc>::
+    _M_fill_assign(size_t __n, const value_type& __val)
+    {
+      if (__n > capacity())
+	{
+	  vector __tmp(__n, __val, _M_get_Tp_allocator());
+	  __tmp._M_impl._M_swap_data(this->_M_impl);
+	}
+      else if (__n > size())
+	{
+	  std::fill(begin(), end(), __val);
+	  const size_type __add = __n - size();
+	  _GLIBCXX_ASAN_ANNOTATE_GROW(__add);
+	  this->_M_impl._M_finish =
+	    std::__uninitialized_fill_n_a(this->_M_impl._M_finish,
+					  __add, __val, _M_get_Tp_allocator());
+	  _GLIBCXX_ASAN_ANNOTATE_GREW(__add);
+	}
+      else
+        _M_erase_at_end(std::fill_n(this->_M_impl._M_start, __n, __val));
+    }
+
+  template<typename _Tp, typename _Alloc>
+    template<typename _InputIterator>
+      _GLIBCXX20_CONSTEXPR
+      void
+      vector<_Tp, _Alloc>::
+      _M_assign_aux(_InputIterator __first, _InputIterator __last,
+		    std::input_iterator_tag)
+      {
+	pointer __cur(this->_M_impl._M_start);
+	for (; __first != __last && __cur != this->_M_impl._M_finish;
+	     ++__cur, (void)++__first)
+	  *__cur = *__first;
+	if (__first == __last)
+	  _M_erase_at_end(__cur);
+	else
+	  _M_range_insert(end(), __first, __last,
+			  std::__iterator_category(__first));
+      }
+
+  template<typename _Tp, typename _Alloc>
+    template<typename _ForwardIterator>
+      _GLIBCXX20_CONSTEXPR
+      void
+      vector<_Tp, _Alloc>::
+      _M_assign_aux(_ForwardIterator __first, _ForwardIterator __last,
+		    std::forward_iterator_tag)
+      {
+	const size_type __len = std::distance(__first, __last);
+
+	if (__len > capacity())
+	  {
+	    _S_check_init_len(__len, _M_get_Tp_allocator());
+	    pointer __tmp(_M_allocate_and_copy(__len, __first, __last));
+	    std::_Destroy(this->_M_impl._M_start, this->_M_impl._M_finish,
+			  _M_get_Tp_allocator());
+	    _GLIBCXX_ASAN_ANNOTATE_REINIT;
+	    _M_deallocate(this->_M_impl._M_start,
+			  this->_M_impl._M_end_of_storage
+			  - this->_M_impl._M_start);
+	    this->_M_impl._M_start = __tmp;
+	    this->_M_impl._M_finish = this->_M_impl._M_start + __len;
+	    this->_M_impl._M_end_of_storage = this->_M_impl._M_finish;
+	  }
+	else if (size() >= __len)
+	  _M_erase_at_end(std::copy(__first, __last, this->_M_impl._M_start));
+	else
+	  {
+	    _ForwardIterator __mid = __first;
+	    std::advance(__mid, size());
+	    std::copy(__first, __mid, this->_M_impl._M_start);
+	    const size_type __attribute__((__unused__)) __n = __len - size();
+	    _GLIBCXX_ASAN_ANNOTATE_GROW(__n);
+	    this->_M_impl._M_finish =
+	      std::__uninitialized_copy_a(__mid, __last,
+					  this->_M_impl._M_finish,
+					  _M_get_Tp_allocator());
+	    _GLIBCXX_ASAN_ANNOTATE_GREW(__n);
+	  }
+      }
+
+#if __cplusplus >= 201103L
+  template<typename _Tp, typename _Alloc>
+    _GLIBCXX20_CONSTEXPR
+    auto
+    vector<_Tp, _Alloc>::
+    _M_insert_rval(const_iterator __position, value_type&& __v) -> iterator
+    {
+      const auto __n = __position - cbegin();
+      if (this->_M_impl._M_finish != this->_M_impl._M_end_of_storage)
+	if (__position == cend())
+	  {
+	    _GLIBCXX_ASAN_ANNOTATE_GROW(1);
+	    _Alloc_traits::construct(this->_M_impl, this->_M_impl._M_finish,
+				     std::move(__v));
+	    ++this->_M_impl._M_finish;
+	    _GLIBCXX_ASAN_ANNOTATE_GREW(1);
+	  }
+	else
+	  _M_insert_aux(begin() + __n, std::move(__v));
+      else
+	_M_realloc_insert(begin() + __n, std::move(__v));
+
+      return iterator(this->_M_impl._M_start + __n);
+    }
+
+  template<typename _Tp, typename _Alloc>
+    template<typename... _Args>
+      _GLIBCXX20_CONSTEXPR
+      auto
+      vector<_Tp, _Alloc>::
+      _M_emplace_aux(const_iterator __position, _Args&&... __args)
+      -> iterator
+      {
+	const auto __n = __position - cbegin();
+	if (this->_M_impl._M_finish != this->_M_impl._M_end_of_storage)
+	  if (__position == cend())
+	    {
+	      _GLIBCXX_ASAN_ANNOTATE_GROW(1);
+	      _Alloc_traits::construct(this->_M_impl, this->_M_impl._M_finish,
+				       std::forward<_Args>(__args)...);
+	      ++this->_M_impl._M_finish;
+	      _GLIBCXX_ASAN_ANNOTATE_GREW(1);
+	    }
+	  else
+	    {
+	      // We need to construct a temporary because something in __args...
+	      // could alias one of the elements of the container and so we
+	      // need to use it before _M_insert_aux moves elements around.
+	      _Temporary_value __tmp(this, std::forward<_Args>(__args)...);
+	      _M_insert_aux(begin() + __n, std::move(__tmp._M_val()));
+	    }
+	else
+	  _M_realloc_insert(begin() + __n, std::forward<_Args>(__args)...);
+
+	return iterator(this->_M_impl._M_start + __n);
+      }
+
+  template<typename _Tp, typename _Alloc>
+    template<typename _Arg>
+      _GLIBCXX20_CONSTEXPR
+      void
+      vector<_Tp, _Alloc>::
+      _M_insert_aux(iterator __position, _Arg&& __arg)
+#else
+  template<typename _Tp, typename _Alloc>
+    void
+    vector<_Tp, _Alloc>::
+    _M_insert_aux(iterator __position, const _Tp& __x)
+#endif
+    {
+      _GLIBCXX_ASAN_ANNOTATE_GROW(1);
+      _Alloc_traits::construct(this->_M_impl, this->_M_impl._M_finish,
+			       _GLIBCXX_MOVE(*(this->_M_impl._M_finish - 1)));
+      ++this->_M_impl._M_finish;
+      _GLIBCXX_ASAN_ANNOTATE_GREW(1);
+#if __cplusplus < 201103L
+      _Tp __x_copy = __x;
+#endif
+      _GLIBCXX_MOVE_BACKWARD3(__position.base(),
+			      this->_M_impl._M_finish - 2,
+			      this->_M_impl._M_finish - 1);
+#if __cplusplus < 201103L
+      *__position = __x_copy;
+#else
+      *__position = std::forward<_Arg>(__arg);
+#endif
+    }
+
+#if __cplusplus >= 201103L
+  template<typename _Tp, typename _Alloc>
+    template<typename... _Args>
+      _GLIBCXX20_CONSTEXPR
+      void
+      vector<_Tp, _Alloc>::
+      _M_realloc_insert(iterator __position, _Args&&... __args)
+#else
+  template<typename _Tp, typename _Alloc>
+    void
+    vector<_Tp, _Alloc>::
+    _M_realloc_insert(iterator __position, const _Tp& __x)
+#endif
+    {
+      const size_type __len =
+	_M_check_len(size_type(1), "vector::_M_realloc_insert");
+      pointer __old_start = this->_M_impl._M_start;
+      pointer __old_finish = this->_M_impl._M_finish;
+      const size_type __elems_before = __position - begin();
+      pointer __new_start(this->_M_allocate(__len));
+      pointer __new_finish(__new_start);
+      __try
+	{
+	  // The order of the three operations is dictated by the C++11
+	  // case, where the moves could alter a new element belonging
+	  // to the existing vector.  This is an issue only for callers
+	  // taking the element by lvalue ref (see last bullet of C++11
+	  // [res.on.arguments]).
+	  _Alloc_traits::construct(this->_M_impl,
+				   __new_start + __elems_before,
+#if __cplusplus >= 201103L
+				   std::forward<_Args>(__args)...);
+#else
+				   __x);
+#endif
+	  __new_finish = pointer();
+
+#if __cplusplus >= 201103L
+	  if _GLIBCXX17_CONSTEXPR (_S_use_relocate())
+	    {
+	      __new_finish = _S_relocate(__old_start, __position.base(),
+					 __new_start, _M_get_Tp_allocator());
+
+	      ++__new_finish;
+
+	      __new_finish = _S_relocate(__position.base(), __old_finish,
+					 __new_finish, _M_get_Tp_allocator());
+	    }
+	  else
+#endif
+	    {
+	      __new_finish
+		= std::__uninitialized_move_if_noexcept_a
+		(__old_start, __position.base(),
+		 __new_start, _M_get_Tp_allocator());
+
+	      ++__new_finish;
+
+	      __new_finish
+		= std::__uninitialized_move_if_noexcept_a
+		(__position.base(), __old_finish,
+		 __new_finish, _M_get_Tp_allocator());
+	    }
+	}
+      __catch(...)
+	{
+	  if (!__new_finish)
+	    _Alloc_traits::destroy(this->_M_impl,
+				   __new_start + __elems_before);
+	  else
+	    std::_Destroy(__new_start, __new_finish, _M_get_Tp_allocator());
+	  _M_deallocate(__new_start, __len);
+	  __throw_exception_again;
+	}
+#if __cplusplus >= 201103L
+      if _GLIBCXX17_CONSTEXPR (!_S_use_relocate())
+#endif
+	std::_Destroy(__old_start, __old_finish, _M_get_Tp_allocator());
+      _GLIBCXX_ASAN_ANNOTATE_REINIT;
+      _M_deallocate(__old_start,
+		    this->_M_impl._M_end_of_storage - __old_start);
+      this->_M_impl._M_start = __new_start;
+      this->_M_impl._M_finish = __new_finish;
+      this->_M_impl._M_end_of_storage = __new_start + __len;
+    }
+
+  template<typename _Tp, typename _Alloc>
+    _GLIBCXX20_CONSTEXPR
+    void
+    vector<_Tp, _Alloc>::
+    _M_fill_insert(iterator __position, size_type __n, const value_type& __x)
+    {
+      if (__n != 0)
+	{
+	  if (size_type(this->_M_impl._M_end_of_storage
+			- this->_M_impl._M_finish) >= __n)
+	    {
+#if __cplusplus < 201103L
+	      value_type __x_copy = __x;
+#else
+	      _Temporary_value __tmp(this, __x);
+	      value_type& __x_copy = __tmp._M_val();
+#endif
+	      const size_type __elems_after = end() - __position;
+	      pointer __old_finish(this->_M_impl._M_finish);
+	      if (__elems_after > __n)
+		{
+		  _GLIBCXX_ASAN_ANNOTATE_GROW(__n);
+		  std::__uninitialized_move_a(this->_M_impl._M_finish - __n,
+					      this->_M_impl._M_finish,
+					      this->_M_impl._M_finish,
+					      _M_get_Tp_allocator());
+		  this->_M_impl._M_finish += __n;
+		  _GLIBCXX_ASAN_ANNOTATE_GREW(__n);
+		  _GLIBCXX_MOVE_BACKWARD3(__position.base(),
+					  __old_finish - __n, __old_finish);
+		  std::fill(__position.base(), __position.base() + __n,
+			    __x_copy);
+		}
+	      else
+		{
+		  _GLIBCXX_ASAN_ANNOTATE_GROW(__n);
+		  this->_M_impl._M_finish =
+		    std::__uninitialized_fill_n_a(this->_M_impl._M_finish,
+						  __n - __elems_after,
+						  __x_copy,
+						  _M_get_Tp_allocator());
+		  _GLIBCXX_ASAN_ANNOTATE_GREW(__n - __elems_after);
+		  std::__uninitialized_move_a(__position.base(), __old_finish,
+					      this->_M_impl._M_finish,
+					      _M_get_Tp_allocator());
+		  this->_M_impl._M_finish += __elems_after;
+		  _GLIBCXX_ASAN_ANNOTATE_GREW(__elems_after);
+		  std::fill(__position.base(), __old_finish, __x_copy);
+		}
+	    }
+	  else
+	    {
+	      const size_type __len =
+		_M_check_len(__n, "vector::_M_fill_insert");
+	      const size_type __elems_before = __position - begin();
+	      pointer __new_start(this->_M_allocate(__len));
+	      pointer __new_finish(__new_start);
+	      __try
+		{
+		  // See _M_realloc_insert above.
+		  std::__uninitialized_fill_n_a(__new_start + __elems_before,
+						__n, __x,
+						_M_get_Tp_allocator());
+		  __new_finish = pointer();
+
+		  __new_finish
+		    = std::__uninitialized_move_if_noexcept_a
+		    (this->_M_impl._M_start, __position.base(),
+		     __new_start, _M_get_Tp_allocator());
+
+		  __new_finish += __n;
+
+		  __new_finish
+		    = std::__uninitialized_move_if_noexcept_a
+		    (__position.base(), this->_M_impl._M_finish,
+		     __new_finish, _M_get_Tp_allocator());
+		}
+	      __catch(...)
+		{
+		  if (!__new_finish)
+		    std::_Destroy(__new_start + __elems_before,
+				  __new_start + __elems_before + __n,
+				  _M_get_Tp_allocator());
+		  else
+		    std::_Destroy(__new_start, __new_finish,
+				  _M_get_Tp_allocator());
+		  _M_deallocate(__new_start, __len);
+		  __throw_exception_again;
+		}
+	      std::_Destroy(this->_M_impl._M_start, this->_M_impl._M_finish,
+			    _M_get_Tp_allocator());
+	      _GLIBCXX_ASAN_ANNOTATE_REINIT;
+	      _M_deallocate(this->_M_impl._M_start,
+			    this->_M_impl._M_end_of_storage
+			    - this->_M_impl._M_start);
+	      this->_M_impl._M_start = __new_start;
+	      this->_M_impl._M_finish = __new_finish;
+	      this->_M_impl._M_end_of_storage = __new_start + __len;
+	    }
+	}
+    }
+
+#if __cplusplus >= 201103L
+  template<typename _Tp, typename _Alloc>
+    _GLIBCXX20_CONSTEXPR
+    void
+    vector<_Tp, _Alloc>::
+    _M_default_append(size_type __n)
+    {
+      if (__n != 0)
+	{
+	  const size_type __size = size();
+	  size_type __navail = size_type(this->_M_impl._M_end_of_storage
+					 - this->_M_impl._M_finish);
+
+	  if (__size > max_size() || __navail > max_size() - __size)
+	    __builtin_unreachable();
+
+	  if (__navail >= __n)
+	    {
+	      _GLIBCXX_ASAN_ANNOTATE_GROW(__n);
+	      this->_M_impl._M_finish =
+		std::__uninitialized_default_n_a(this->_M_impl._M_finish,
+						 __n, _M_get_Tp_allocator());
+	      _GLIBCXX_ASAN_ANNOTATE_GREW(__n);
+	    }
+	  else
+	    {
+	      const size_type __len =
+		_M_check_len(__n, "vector::_M_default_append");
+	      pointer __new_start(this->_M_allocate(__len));
+	      if _GLIBCXX17_CONSTEXPR (_S_use_relocate())
+		{
+		  __try
+		    {
+		      std::__uninitialized_default_n_a(__new_start + __size,
+			      __n, _M_get_Tp_allocator());
+		    }
+		  __catch(...)
+		    {
+		      _M_deallocate(__new_start, __len);
+		      __throw_exception_again;
+		    }
+		  _S_relocate(this->_M_impl._M_start, this->_M_impl._M_finish,
+			      __new_start, _M_get_Tp_allocator());
+		}
+	      else
+		{
+		  pointer __destroy_from = pointer();
+		  __try
+		    {
+		      std::__uninitialized_default_n_a(__new_start + __size,
+			      __n, _M_get_Tp_allocator());
+		      __destroy_from = __new_start + __size;
+		      std::__uninitialized_move_if_noexcept_a(
+			      this->_M_impl._M_start, this->_M_impl._M_finish,
+			      __new_start, _M_get_Tp_allocator());
+		    }
+		  __catch(...)
+		    {
+		      if (__destroy_from)
+			std::_Destroy(__destroy_from, __destroy_from + __n,
+				      _M_get_Tp_allocator());
+		      _M_deallocate(__new_start, __len);
+		      __throw_exception_again;
+		    }
+		  std::_Destroy(this->_M_impl._M_start, this->_M_impl._M_finish,
+				_M_get_Tp_allocator());
+		}
+	      _GLIBCXX_ASAN_ANNOTATE_REINIT;
+	      _M_deallocate(this->_M_impl._M_start,
+			    this->_M_impl._M_end_of_storage
+			    - this->_M_impl._M_start);
+	      this->_M_impl._M_start = __new_start;
+	      this->_M_impl._M_finish = __new_start + __size + __n;
+	      this->_M_impl._M_end_of_storage = __new_start + __len;
+	    }
+	}
+    }
+
+  template<typename _Tp, typename _Alloc>
+    _GLIBCXX20_CONSTEXPR
+    bool
+    vector<_Tp, _Alloc>::
+    _M_shrink_to_fit()
+    {
+      if (capacity() == size())
+	return false;
+      _GLIBCXX_ASAN_ANNOTATE_REINIT;
+      return std::__shrink_to_fit_aux<vector>::_S_do_it(*this);
+    }
+#endif
+
+  template<typename _Tp, typename _Alloc>
+    template<typename _InputIterator>
+      _GLIBCXX20_CONSTEXPR
+      void
+      vector<_Tp, _Alloc>::
+      _M_range_insert(iterator __pos, _InputIterator __first,
+		      _InputIterator __last, std::input_iterator_tag)
+      {
+	if (__pos == end())
+	  {
+	    for (; __first != __last; ++__first)
+	      insert(end(), *__first);
+	  }
+	else if (__first != __last)
+	  {
+	    vector __tmp(__first, __last, _M_get_Tp_allocator());
+	    insert(__pos,
+		   _GLIBCXX_MAKE_MOVE_ITERATOR(__tmp.begin()),
+		   _GLIBCXX_MAKE_MOVE_ITERATOR(__tmp.end()));
+	  }
+      }
+
+  template<typename _Tp, typename _Alloc>
+    template<typename _ForwardIterator>
+      _GLIBCXX20_CONSTEXPR
+      void
+      vector<_Tp, _Alloc>::
+      _M_range_insert(iterator __position, _ForwardIterator __first,
+		      _ForwardIterator __last, std::forward_iterator_tag)
+      {
+	if (__first != __last)
+	  {
+	    const size_type __n = std::distance(__first, __last);
+	    if (size_type(this->_M_impl._M_end_of_storage
+			  - this->_M_impl._M_finish) >= __n)
+	      {
+		const size_type __elems_after = end() - __position;
+		pointer __old_finish(this->_M_impl._M_finish);
+		if (__elems_after > __n)
+		  {
+		    _GLIBCXX_ASAN_ANNOTATE_GROW(__n);
+		    std::__uninitialized_move_a(this->_M_impl._M_finish - __n,
+						this->_M_impl._M_finish,
+						this->_M_impl._M_finish,
+						_M_get_Tp_allocator());
+		    this->_M_impl._M_finish += __n;
+		    _GLIBCXX_ASAN_ANNOTATE_GREW(__n);
+		    _GLIBCXX_MOVE_BACKWARD3(__position.base(),
+					    __old_finish - __n, __old_finish);
+		    std::copy(__first, __last, __position);
+		  }
+		else
+		  {
+		    _ForwardIterator __mid = __first;
+		    std::advance(__mid, __elems_after);
+		    _GLIBCXX_ASAN_ANNOTATE_GROW(__n);
+		    std::__uninitialized_copy_a(__mid, __last,
+						this->_M_impl._M_finish,
+						_M_get_Tp_allocator());
+		    this->_M_impl._M_finish += __n - __elems_after;
+		    _GLIBCXX_ASAN_ANNOTATE_GREW(__n - __elems_after);
+		    std::__uninitialized_move_a(__position.base(),
+						__old_finish,
+						this->_M_impl._M_finish,
+						_M_get_Tp_allocator());
+		    this->_M_impl._M_finish += __elems_after;
+		    _GLIBCXX_ASAN_ANNOTATE_GREW(__elems_after);
+		    std::copy(__first, __mid, __position);
+		  }
+	      }
+	    else
+	      {
+		const size_type __len =
+		  _M_check_len(__n, "vector::_M_range_insert");
+		pointer __new_start(this->_M_allocate(__len));
+		pointer __new_finish(__new_start);
+		__try
+		  {
+		    __new_finish
+		      = std::__uninitialized_move_if_noexcept_a
+		      (this->_M_impl._M_start, __position.base(),
+		       __new_start, _M_get_Tp_allocator());
+		    __new_finish
+		      = std::__uninitialized_copy_a(__first, __last,
+						    __new_finish,
+						    _M_get_Tp_allocator());
+		    __new_finish
+		      = std::__uninitialized_move_if_noexcept_a
+		      (__position.base(), this->_M_impl._M_finish,
+		       __new_finish, _M_get_Tp_allocator());
+		  }
+		__catch(...)
+		  {
+		    std::_Destroy(__new_start, __new_finish,
+				  _M_get_Tp_allocator());
+		    _M_deallocate(__new_start, __len);
+		    __throw_exception_again;
+		  }
+		std::_Destroy(this->_M_impl._M_start, this->_M_impl._M_finish,
+			      _M_get_Tp_allocator());
+		_GLIBCXX_ASAN_ANNOTATE_REINIT;
+		_M_deallocate(this->_M_impl._M_start,
+			      this->_M_impl._M_end_of_storage
+			      - this->_M_impl._M_start);
+		this->_M_impl._M_start = __new_start;
+		this->_M_impl._M_finish = __new_finish;
+		this->_M_impl._M_end_of_storage = __new_start + __len;
+	      }
+	  }
+      }
+
+
+  // vector<bool>
+  template<typename _Alloc>
+    _GLIBCXX20_CONSTEXPR
+    void
+    vector<bool, _Alloc>::
+    _M_reallocate(size_type __n)
+    {
+      _Bit_pointer __q = this->_M_allocate(__n);
+      iterator __start(std::__addressof(*__q), 0);
+      iterator __finish(_M_copy_aligned(begin(), end(), __start));
+      this->_M_deallocate();
+      this->_M_impl._M_start = __start;
+      this->_M_impl._M_finish = __finish;
+      this->_M_impl._M_end_of_storage = __q + _S_nword(__n);
+    }
+
+  template<typename _Alloc>
+    _GLIBCXX20_CONSTEXPR
+    void
+    vector<bool, _Alloc>::
+    _M_fill_insert(iterator __position, size_type __n, bool __x)
+    {
+      if (__n == 0)
+	return;
+      if (capacity() - size() >= __n)
+	{
+	  std::copy_backward(__position, end(),
+			     this->_M_impl._M_finish + difference_type(__n));
+	  std::fill(__position, __position + difference_type(__n), __x);
+	  this->_M_impl._M_finish += difference_type(__n);
+	}
+      else
+	{
+	  const size_type __len = 
+	    _M_check_len(__n, "vector<bool>::_M_fill_insert");
+	  _Bit_pointer __q = this->_M_allocate(__len);
+	  iterator __start(std::__addressof(*__q), 0);
+	  iterator __i = _M_copy_aligned(begin(), __position, __start);
+	  std::fill(__i, __i + difference_type(__n), __x);
+	  iterator __finish = std::copy(__position, end(),
+					__i + difference_type(__n));
+	  this->_M_deallocate();
+	  this->_M_impl._M_end_of_storage = __q + _S_nword(__len);
+	  this->_M_impl._M_start = __start;
+	  this->_M_impl._M_finish = __finish;
+	}
+    }
+
+  template<typename _Alloc>
+    template<typename _ForwardIterator>
+      _GLIBCXX20_CONSTEXPR
+      void
+      vector<bool, _Alloc>::
+      _M_insert_range(iterator __position, _ForwardIterator __first, 
+		      _ForwardIterator __last, std::forward_iterator_tag)
+      {
+	if (__first != __last)
+	  {
+	    size_type __n = std::distance(__first, __last);
+	    if (capacity() - size() >= __n)
+	      {
+		std::copy_backward(__position, end(),
+				   this->_M_impl._M_finish
+				   + difference_type(__n));
+		std::copy(__first, __last, __position);
+		this->_M_impl._M_finish += difference_type(__n);
+	      }
+	    else
+	      {
+		const size_type __len =
+		  _M_check_len(__n, "vector<bool>::_M_insert_range");
+		_Bit_pointer __q = this->_M_allocate(__len);
+		iterator __start(std::__addressof(*__q), 0);
+		iterator __i = _M_copy_aligned(begin(), __position, __start);
+		__i = std::copy(__first, __last, __i);
+		iterator __finish = std::copy(__position, end(), __i);
+		this->_M_deallocate();
+		this->_M_impl._M_end_of_storage = __q + _S_nword(__len);
+		this->_M_impl._M_start = __start;
+		this->_M_impl._M_finish = __finish;
+	      }
+	  }
+      }
+
+  template<typename _Alloc>
+    _GLIBCXX20_CONSTEXPR
+    void
+    vector<bool, _Alloc>::
+    _M_insert_aux(iterator __position, bool __x)
+    {
+      if (this->_M_impl._M_finish._M_p != this->_M_impl._M_end_addr())
+	{
+	  std::copy_backward(__position, this->_M_impl._M_finish, 
+			     this->_M_impl._M_finish + 1);
+	  *__position = __x;
+	  ++this->_M_impl._M_finish;
+	}
+      else
+	{
+	  const size_type __len =
+	    _M_check_len(size_type(1), "vector<bool>::_M_insert_aux");
+	  _Bit_pointer __q = this->_M_allocate(__len);
+	  iterator __start(std::__addressof(*__q), 0);
+	  iterator __i = _M_copy_aligned(begin(), __position, __start);
+	  *__i++ = __x;
+	  iterator __finish = std::copy(__position, end(), __i);
+	  this->_M_deallocate();
+	  this->_M_impl._M_end_of_storage = __q + _S_nword(__len);
+	  this->_M_impl._M_start = __start;
+	  this->_M_impl._M_finish = __finish;
+	}
+    }
+
+  template<typename _Alloc>
+    _GLIBCXX20_CONSTEXPR
+    typename vector<bool, _Alloc>::iterator
+    vector<bool, _Alloc>::
+    _M_erase(iterator __position)
+    {
+      if (__position + 1 != end())
+        std::copy(__position + 1, end(), __position);
+      --this->_M_impl._M_finish;
+      return __position;
+    }
+
+  template<typename _Alloc>
+    _GLIBCXX20_CONSTEXPR
+    typename vector<bool, _Alloc>::iterator
+    vector<bool, _Alloc>::
+    _M_erase(iterator __first, iterator __last)
+    {
+      if (__first != __last)
+	_M_erase_at_end(std::copy(__last, end(), __first));
+      return __first;
+    }
+
+#if __cplusplus >= 201103L
+  template<typename _Alloc>
+    _GLIBCXX20_CONSTEXPR
+    bool
+    vector<bool, _Alloc>::
+    _M_shrink_to_fit()
+    {
+      if (capacity() - size() < int(_S_word_bit))
+	return false;
+      __try
+	{
+	  if (size_type __n = size())
+	    _M_reallocate(__n);
+	  else
+	    {
+	      this->_M_deallocate();
+	      this->_M_impl._M_reset();
+	    }
+	  return true;
+	}
+      __catch(...)
+	{ return false; }
+    }
+#endif
+
+_GLIBCXX_END_NAMESPACE_CONTAINER
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#if __cplusplus >= 201103L
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  template<typename _Alloc>
+    size_t
+    hash<_GLIBCXX_STD_C::vector<bool, _Alloc>>::
+    operator()(const _GLIBCXX_STD_C::vector<bool, _Alloc>& __b) const noexcept
+    {
+      size_t __hash = 0;
+      const size_t __words = __b.size() / _S_word_bit;
+      if (__words)
+	{
+	  const size_t __clength = __words * sizeof(_Bit_type);
+	  __hash = std::_Hash_impl::hash(__b._M_impl._M_start._M_p, __clength);
+	}
+
+      const size_t __extrabits = __b.size() % _S_word_bit;
+      if (__extrabits)
+	{
+	  _Bit_type __hiword = *__b._M_impl._M_finish._M_p;
+	  __hiword &= ~((~static_cast<_Bit_type>(0)) << __extrabits);
+
+	  const size_t __clength
+	    = (__extrabits + __CHAR_BIT__ - 1) / __CHAR_BIT__;
+	  if (__words)
+	    __hash = std::_Hash_impl::hash(&__hiword, __clength, __hash);
+	  else
+	    __hash = std::_Hash_impl::hash(&__hiword, __clength);
+	}
+
+      return __hash;
+    }
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif // C++11
+
+#undef _GLIBCXX_ASAN_ANNOTATE_REINIT
+#undef _GLIBCXX_ASAN_ANNOTATE_GROW
+#undef _GLIBCXX_ASAN_ANNOTATE_GREW
+#undef _GLIBCXX_ASAN_ANNOTATE_SHRINK
+
+#endif /* _VECTOR_TCC */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@vector.tcc.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@vector.tcc.blob
new file mode 100644
index 0000000000000000000000000000000000000000..b760cb1dc6d39cfae930a2c716793ea981c82335
Binary files /dev/null and b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bits@vector.tcc.blob differ
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bitset b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bitset
new file mode 100644
index 0000000000000000000000000000000000000000..438c2f7efe9281c4dec5a9e37960be569da12045
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bitset
@@ -0,0 +1,1598 @@
+// <bitset> -*- C++ -*-
+
+// Copyright (C) 2001-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/*
+ * Copyright (c) 1998
+ * Silicon Graphics Computer Systems, Inc.
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Silicon Graphics makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ */
+
+/** @file include/bitset
+ *  This is a Standard C++ Library header.
+ */
+
+#ifndef _GLIBCXX_BITSET
+#define _GLIBCXX_BITSET 1
+
+#pragma GCC system_header
+
+#include <string>
+#include <bits/functexcept.h>   // For invalid_argument, out_of_range,
+                                // overflow_error
+#include <iosfwd>
+#include <bits/cxxabi_forced.h>
+
+#if __cplusplus >= 201103L
+# include <bits/functional_hash.h>
+#endif
+
+#define _GLIBCXX_BITSET_BITS_PER_WORD  (__CHAR_BIT__ * __SIZEOF_LONG__)
+#define _GLIBCXX_BITSET_WORDS(__n) \
+  ((__n) / _GLIBCXX_BITSET_BITS_PER_WORD + \
+   ((__n) % _GLIBCXX_BITSET_BITS_PER_WORD == 0 ? 0 : 1))
+
+#define _GLIBCXX_BITSET_BITS_PER_ULL (__CHAR_BIT__ * __SIZEOF_LONG_LONG__)
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_CONTAINER
+
+  /**
+   *  Base class, general case.  It is a class invariant that _Nw will be
+   *  nonnegative.
+   *
+   *  See documentation for bitset.
+  */
+  template<size_t _Nw>
+    struct _Base_bitset
+    {
+      typedef unsigned long _WordT;
+
+      /// 0 is the least significant word.
+      _WordT 		_M_w[_Nw];
+
+      _GLIBCXX_CONSTEXPR _Base_bitset() _GLIBCXX_NOEXCEPT
+      : _M_w() { }
+
+#if __cplusplus >= 201103L
+      constexpr _Base_bitset(unsigned long long __val) noexcept
+      : _M_w{ _WordT(__val)
+#if __SIZEOF_LONG_LONG__ > __SIZEOF_LONG__
+	       , _WordT(__val >> _GLIBCXX_BITSET_BITS_PER_WORD)
+#endif
+       } { }
+#else
+      _Base_bitset(unsigned long __val)
+      : _M_w()
+      { _M_w[0] = __val; }
+#endif
+
+      static _GLIBCXX_CONSTEXPR size_t
+      _S_whichword(size_t __pos) _GLIBCXX_NOEXCEPT
+      { return __pos / _GLIBCXX_BITSET_BITS_PER_WORD; }
+
+      static _GLIBCXX_CONSTEXPR size_t
+      _S_whichbyte(size_t __pos) _GLIBCXX_NOEXCEPT
+      { return (__pos % _GLIBCXX_BITSET_BITS_PER_WORD) / __CHAR_BIT__; }
+
+      static _GLIBCXX_CONSTEXPR size_t
+      _S_whichbit(size_t __pos) _GLIBCXX_NOEXCEPT
+      { return __pos % _GLIBCXX_BITSET_BITS_PER_WORD; }
+
+      static _GLIBCXX_CONSTEXPR _WordT
+      _S_maskbit(size_t __pos) _GLIBCXX_NOEXCEPT
+      { return (static_cast<_WordT>(1)) << _S_whichbit(__pos); }
+
+      _WordT&
+      _M_getword(size_t __pos) _GLIBCXX_NOEXCEPT
+      { return _M_w[_S_whichword(__pos)]; }
+
+      _GLIBCXX_CONSTEXPR _WordT
+      _M_getword(size_t __pos) const _GLIBCXX_NOEXCEPT
+      { return _M_w[_S_whichword(__pos)]; }
+
+#if __cplusplus >= 201103L
+      const _WordT*
+      _M_getdata() const noexcept
+      { return _M_w; }
+#endif
+
+      _WordT&
+      _M_hiword() _GLIBCXX_NOEXCEPT
+      { return _M_w[_Nw - 1]; }
+
+      _GLIBCXX_CONSTEXPR _WordT
+      _M_hiword() const _GLIBCXX_NOEXCEPT
+      { return _M_w[_Nw - 1]; }
+
+      void
+      _M_do_and(const _Base_bitset<_Nw>& __x) _GLIBCXX_NOEXCEPT
+      {
+	for (size_t __i = 0; __i < _Nw; __i++)
+	  _M_w[__i] &= __x._M_w[__i];
+      }
+
+      void
+      _M_do_or(const _Base_bitset<_Nw>& __x) _GLIBCXX_NOEXCEPT
+      {
+	for (size_t __i = 0; __i < _Nw; __i++)
+	  _M_w[__i] |= __x._M_w[__i];
+      }
+
+      void
+      _M_do_xor(const _Base_bitset<_Nw>& __x) _GLIBCXX_NOEXCEPT
+      {
+	for (size_t __i = 0; __i < _Nw; __i++)
+	  _M_w[__i] ^= __x._M_w[__i];
+      }
+
+      void
+      _M_do_left_shift(size_t __shift) _GLIBCXX_NOEXCEPT;
+
+      void
+      _M_do_right_shift(size_t __shift) _GLIBCXX_NOEXCEPT;
+
+      void
+      _M_do_flip() _GLIBCXX_NOEXCEPT
+      {
+	for (size_t __i = 0; __i < _Nw; __i++)
+	  _M_w[__i] = ~_M_w[__i];
+      }
+
+      void
+      _M_do_set() _GLIBCXX_NOEXCEPT
+      {
+	for (size_t __i = 0; __i < _Nw; __i++)
+	  _M_w[__i] = ~static_cast<_WordT>(0);
+      }
+
+      void
+      _M_do_reset() _GLIBCXX_NOEXCEPT
+      { __builtin_memset(_M_w, 0, _Nw * sizeof(_WordT)); }
+
+      bool
+      _M_is_equal(const _Base_bitset<_Nw>& __x) const _GLIBCXX_NOEXCEPT
+      {
+	for (size_t __i = 0; __i < _Nw; ++__i)
+	  if (_M_w[__i] != __x._M_w[__i])
+	    return false;
+	return true;
+      }
+
+      template<size_t _Nb>
+        bool
+        _M_are_all() const _GLIBCXX_NOEXCEPT
+        {
+	  for (size_t __i = 0; __i < _Nw - 1; __i++)
+	    if (_M_w[__i] != ~static_cast<_WordT>(0))
+	      return false;
+	  return _M_hiword() == (~static_cast<_WordT>(0)
+				 >> (_Nw * _GLIBCXX_BITSET_BITS_PER_WORD
+				     - _Nb));
+	}
+
+      bool
+      _M_is_any() const _GLIBCXX_NOEXCEPT
+      {
+	for (size_t __i = 0; __i < _Nw; __i++)
+	  if (_M_w[__i] != static_cast<_WordT>(0))
+	    return true;
+	return false;
+      }
+
+      size_t
+      _M_do_count() const _GLIBCXX_NOEXCEPT
+      {
+	size_t __result = 0;
+	for (size_t __i = 0; __i < _Nw; __i++)
+	  __result += __builtin_popcountl(_M_w[__i]);
+	return __result;
+      }
+
+      unsigned long
+      _M_do_to_ulong() const;
+
+#if __cplusplus >= 201103L
+      unsigned long long
+      _M_do_to_ullong() const;
+#endif
+
+      // find first "on" bit
+      size_t
+      _M_do_find_first(size_t) const _GLIBCXX_NOEXCEPT;
+
+      // find the next "on" bit that follows "prev"
+      size_t
+      _M_do_find_next(size_t, size_t) const _GLIBCXX_NOEXCEPT;
+    };
+
+  // Definitions of non-inline functions from _Base_bitset.
+  template<size_t _Nw>
+    void
+    _Base_bitset<_Nw>::_M_do_left_shift(size_t __shift) _GLIBCXX_NOEXCEPT
+    {
+      if (__builtin_expect(__shift != 0, 1))
+	{
+	  const size_t __wshift = __shift / _GLIBCXX_BITSET_BITS_PER_WORD;
+	  const size_t __offset = __shift % _GLIBCXX_BITSET_BITS_PER_WORD;
+
+	  if (__offset == 0)
+	    for (size_t __n = _Nw - 1; __n >= __wshift; --__n)
+	      _M_w[__n] = _M_w[__n - __wshift];
+	  else
+	    {
+	      const size_t __sub_offset = (_GLIBCXX_BITSET_BITS_PER_WORD
+					   - __offset);
+	      for (size_t __n = _Nw - 1; __n > __wshift; --__n)
+		_M_w[__n] = ((_M_w[__n - __wshift] << __offset)
+			     | (_M_w[__n - __wshift - 1] >> __sub_offset));
+	      _M_w[__wshift] = _M_w[0] << __offset;
+	    }
+
+	  std::fill(_M_w + 0, _M_w + __wshift, static_cast<_WordT>(0));
+	}
+    }
+
+  template<size_t _Nw>
+    void
+    _Base_bitset<_Nw>::_M_do_right_shift(size_t __shift) _GLIBCXX_NOEXCEPT
+    {
+      if (__builtin_expect(__shift != 0, 1))
+	{
+	  const size_t __wshift = __shift / _GLIBCXX_BITSET_BITS_PER_WORD;
+	  const size_t __offset = __shift % _GLIBCXX_BITSET_BITS_PER_WORD;
+	  const size_t __limit = _Nw - __wshift - 1;
+
+	  if (__offset == 0)
+	    for (size_t __n = 0; __n <= __limit; ++__n)
+	      _M_w[__n] = _M_w[__n + __wshift];
+	  else
+	    {
+	      const size_t __sub_offset = (_GLIBCXX_BITSET_BITS_PER_WORD
+					   - __offset);
+	      for (size_t __n = 0; __n < __limit; ++__n)
+		_M_w[__n] = ((_M_w[__n + __wshift] >> __offset)
+			     | (_M_w[__n + __wshift + 1] << __sub_offset));
+	      _M_w[__limit] = _M_w[_Nw-1] >> __offset;
+	    }
+
+	  std::fill(_M_w + __limit + 1, _M_w + _Nw, static_cast<_WordT>(0));
+	}
+    }
+
+  template<size_t _Nw>
+    unsigned long
+    _Base_bitset<_Nw>::_M_do_to_ulong() const
+    {
+      for (size_t __i = 1; __i < _Nw; ++__i)
+	if (_M_w[__i])
+	  __throw_overflow_error(__N("_Base_bitset::_M_do_to_ulong"));
+      return _M_w[0];
+    }
+
+#if __cplusplus >= 201103L
+  template<size_t _Nw>
+    unsigned long long
+    _Base_bitset<_Nw>::_M_do_to_ullong() const
+    {
+      const bool __dw = sizeof(unsigned long long) > sizeof(unsigned long);
+      for (size_t __i = 1 + __dw; __i < _Nw; ++__i)
+	if (_M_w[__i])
+	  __throw_overflow_error(__N("_Base_bitset::_M_do_to_ullong"));
+
+      if (__dw)
+	return _M_w[0] + (static_cast<unsigned long long>(_M_w[1])
+			  << _GLIBCXX_BITSET_BITS_PER_WORD);
+      return _M_w[0];
+    }
+#endif
+
+  template<size_t _Nw>
+    size_t
+    _Base_bitset<_Nw>::
+    _M_do_find_first(size_t __not_found) const _GLIBCXX_NOEXCEPT
+    {
+      for (size_t __i = 0; __i < _Nw; __i++)
+	{
+	  _WordT __thisword = _M_w[__i];
+	  if (__thisword != static_cast<_WordT>(0))
+	    return (__i * _GLIBCXX_BITSET_BITS_PER_WORD
+		    + __builtin_ctzl(__thisword));
+	}
+      // not found, so return an indication of failure.
+      return __not_found;
+    }
+
+  template<size_t _Nw>
+    size_t
+    _Base_bitset<_Nw>::
+    _M_do_find_next(size_t __prev, size_t __not_found) const _GLIBCXX_NOEXCEPT
+    {
+      // make bound inclusive
+      ++__prev;
+
+      // check out of bounds
+      if (__prev >= _Nw * _GLIBCXX_BITSET_BITS_PER_WORD)
+	return __not_found;
+
+      // search first word
+      size_t __i = _S_whichword(__prev);
+      _WordT __thisword = _M_w[__i];
+
+      // mask off bits below bound
+      __thisword &= (~static_cast<_WordT>(0)) << _S_whichbit(__prev);
+
+      if (__thisword != static_cast<_WordT>(0))
+	return (__i * _GLIBCXX_BITSET_BITS_PER_WORD
+		+ __builtin_ctzl(__thisword));
+
+      // check subsequent words
+      __i++;
+      for (; __i < _Nw; __i++)
+	{
+	  __thisword = _M_w[__i];
+	  if (__thisword != static_cast<_WordT>(0))
+	    return (__i * _GLIBCXX_BITSET_BITS_PER_WORD
+		    + __builtin_ctzl(__thisword));
+	}
+      // not found, so return an indication of failure.
+      return __not_found;
+    } // end _M_do_find_next
+
+  /**
+   *  Base class, specialization for a single word.
+   *
+   *  See documentation for bitset.
+  */
+  template<>
+    struct _Base_bitset<1>
+    {
+      typedef unsigned long _WordT;
+      _WordT _M_w;
+
+      _GLIBCXX_CONSTEXPR _Base_bitset() _GLIBCXX_NOEXCEPT
+      : _M_w(0)
+      { }
+
+#if __cplusplus >= 201103L
+      constexpr _Base_bitset(unsigned long long __val) noexcept
+#else
+      _Base_bitset(unsigned long __val)
+#endif
+      : _M_w(__val)
+      { }
+
+      static _GLIBCXX_CONSTEXPR size_t
+      _S_whichword(size_t __pos) _GLIBCXX_NOEXCEPT
+      { return __pos / _GLIBCXX_BITSET_BITS_PER_WORD; }
+
+      static _GLIBCXX_CONSTEXPR size_t
+      _S_whichbyte(size_t __pos) _GLIBCXX_NOEXCEPT
+      { return (__pos % _GLIBCXX_BITSET_BITS_PER_WORD) / __CHAR_BIT__; }
+
+      static _GLIBCXX_CONSTEXPR size_t
+      _S_whichbit(size_t __pos) _GLIBCXX_NOEXCEPT
+      {  return __pos % _GLIBCXX_BITSET_BITS_PER_WORD; }
+
+      static _GLIBCXX_CONSTEXPR _WordT
+      _S_maskbit(size_t __pos) _GLIBCXX_NOEXCEPT
+      { return (static_cast<_WordT>(1)) << _S_whichbit(__pos); }
+
+      _WordT&
+      _M_getword(size_t) _GLIBCXX_NOEXCEPT
+      { return _M_w; }
+
+      _GLIBCXX_CONSTEXPR _WordT
+      _M_getword(size_t) const _GLIBCXX_NOEXCEPT
+      { return _M_w; }
+
+#if __cplusplus >= 201103L
+      const _WordT*
+      _M_getdata() const noexcept
+      { return &_M_w; }
+#endif
+
+      _WordT&
+      _M_hiword() _GLIBCXX_NOEXCEPT
+      { return _M_w; }
+
+      _GLIBCXX_CONSTEXPR _WordT
+      _M_hiword() const _GLIBCXX_NOEXCEPT
+      { return _M_w; }
+
+      void
+      _M_do_and(const _Base_bitset<1>& __x) _GLIBCXX_NOEXCEPT
+      { _M_w &= __x._M_w; }
+
+      void
+      _M_do_or(const _Base_bitset<1>& __x) _GLIBCXX_NOEXCEPT
+      { _M_w |= __x._M_w; }
+
+      void
+      _M_do_xor(const _Base_bitset<1>& __x) _GLIBCXX_NOEXCEPT
+      { _M_w ^= __x._M_w; }
+
+      void
+      _M_do_left_shift(size_t __shift) _GLIBCXX_NOEXCEPT
+      { _M_w <<= __shift; }
+
+      void
+      _M_do_right_shift(size_t __shift) _GLIBCXX_NOEXCEPT
+      { _M_w >>= __shift; }
+
+      void
+      _M_do_flip() _GLIBCXX_NOEXCEPT
+      { _M_w = ~_M_w; }
+
+      void
+      _M_do_set() _GLIBCXX_NOEXCEPT
+      { _M_w = ~static_cast<_WordT>(0); }
+
+      void
+      _M_do_reset() _GLIBCXX_NOEXCEPT
+      { _M_w = 0; }
+
+      bool
+      _M_is_equal(const _Base_bitset<1>& __x) const _GLIBCXX_NOEXCEPT
+      { return _M_w == __x._M_w; }
+
+      template<size_t _Nb>
+        bool
+        _M_are_all() const _GLIBCXX_NOEXCEPT
+        { return _M_w == (~static_cast<_WordT>(0)
+			  >> (_GLIBCXX_BITSET_BITS_PER_WORD - _Nb)); }
+
+      bool
+      _M_is_any() const _GLIBCXX_NOEXCEPT
+      { return _M_w != 0; }
+
+      size_t
+      _M_do_count() const _GLIBCXX_NOEXCEPT
+      { return __builtin_popcountl(_M_w); }
+
+      unsigned long
+      _M_do_to_ulong() const _GLIBCXX_NOEXCEPT
+      { return _M_w; }
+
+#if __cplusplus >= 201103L
+      unsigned long long
+      _M_do_to_ullong() const noexcept
+      { return _M_w; }
+#endif
+
+      size_t
+      _M_do_find_first(size_t __not_found) const _GLIBCXX_NOEXCEPT
+      {
+        if (_M_w != 0)
+          return __builtin_ctzl(_M_w);
+        else
+          return __not_found;
+      }
+
+      // find the next "on" bit that follows "prev"
+      size_t
+      _M_do_find_next(size_t __prev, size_t __not_found) const
+	_GLIBCXX_NOEXCEPT
+      {
+	++__prev;
+	if (__prev >= ((size_t) _GLIBCXX_BITSET_BITS_PER_WORD))
+	  return __not_found;
+
+	_WordT __x = _M_w >> __prev;
+	if (__x != 0)
+	  return __builtin_ctzl(__x) + __prev;
+	else
+	  return __not_found;
+      }
+    };
+
+  /**
+   *  Base class, specialization for no storage (zero-length %bitset).
+   *
+   *  See documentation for bitset.
+  */
+  template<>
+    struct _Base_bitset<0>
+    {
+      typedef unsigned long _WordT;
+
+      _GLIBCXX_CONSTEXPR _Base_bitset() _GLIBCXX_NOEXCEPT
+      { }
+
+#if __cplusplus >= 201103L
+      constexpr _Base_bitset(unsigned long long) noexcept
+#else
+      _Base_bitset(unsigned long)
+#endif
+      { }
+
+      static _GLIBCXX_CONSTEXPR size_t
+      _S_whichword(size_t __pos) _GLIBCXX_NOEXCEPT
+      { return __pos / _GLIBCXX_BITSET_BITS_PER_WORD; }
+
+      static _GLIBCXX_CONSTEXPR size_t
+      _S_whichbyte(size_t __pos) _GLIBCXX_NOEXCEPT
+      { return (__pos % _GLIBCXX_BITSET_BITS_PER_WORD) / __CHAR_BIT__; }
+
+      static _GLIBCXX_CONSTEXPR size_t
+      _S_whichbit(size_t __pos) _GLIBCXX_NOEXCEPT
+      {  return __pos % _GLIBCXX_BITSET_BITS_PER_WORD; }
+
+      static _GLIBCXX_CONSTEXPR _WordT
+      _S_maskbit(size_t __pos) _GLIBCXX_NOEXCEPT
+      { return (static_cast<_WordT>(1)) << _S_whichbit(__pos); }
+
+      // This would normally give access to the data.  The bounds-checking
+      // in the bitset class will prevent the user from getting this far,
+      // but (1) it must still return an lvalue to compile, and (2) the
+      // user might call _Unchecked_set directly, in which case this /needs/
+      // to fail.  Let's not penalize zero-length users unless they actually
+      // make an unchecked call; all the memory ugliness is therefore
+      // localized to this single should-never-get-this-far function.
+      _WordT&
+      _M_getword(size_t) _GLIBCXX_NOEXCEPT
+      {
+	__throw_out_of_range(__N("_Base_bitset::_M_getword"));
+	return *new _WordT;
+      }
+
+      _GLIBCXX_CONSTEXPR _WordT
+      _M_getword(size_t) const _GLIBCXX_NOEXCEPT
+      { return 0; }
+
+      _GLIBCXX_CONSTEXPR _WordT
+      _M_hiword() const _GLIBCXX_NOEXCEPT
+      { return 0; }
+
+      void
+      _M_do_and(const _Base_bitset<0>&) _GLIBCXX_NOEXCEPT
+      { }
+
+      void
+      _M_do_or(const _Base_bitset<0>&) _GLIBCXX_NOEXCEPT
+      { }
+
+      void
+      _M_do_xor(const _Base_bitset<0>&) _GLIBCXX_NOEXCEPT
+      { }
+
+      void
+      _M_do_left_shift(size_t) _GLIBCXX_NOEXCEPT
+      { }
+
+      void
+      _M_do_right_shift(size_t) _GLIBCXX_NOEXCEPT
+      { }
+
+      void
+      _M_do_flip() _GLIBCXX_NOEXCEPT
+      { }
+
+      void
+      _M_do_set() _GLIBCXX_NOEXCEPT
+      { }
+
+      void
+      _M_do_reset() _GLIBCXX_NOEXCEPT
+      { }
+
+      // Are all empty bitsets equal to each other?  Are they equal to
+      // themselves?  How to compare a thing which has no state?  What is
+      // the sound of one zero-length bitset clapping?
+      bool
+      _M_is_equal(const _Base_bitset<0>&) const _GLIBCXX_NOEXCEPT
+      { return true; }
+
+      template<size_t _Nb>
+        bool
+        _M_are_all() const _GLIBCXX_NOEXCEPT
+        { return true; }
+
+      bool
+      _M_is_any() const _GLIBCXX_NOEXCEPT
+      { return false; }
+
+      size_t
+      _M_do_count() const _GLIBCXX_NOEXCEPT
+      { return 0; }
+
+      unsigned long
+      _M_do_to_ulong() const _GLIBCXX_NOEXCEPT
+      { return 0; }
+
+#if __cplusplus >= 201103L
+      unsigned long long
+      _M_do_to_ullong() const noexcept
+      { return 0; }
+#endif
+
+      // Normally "not found" is the size, but that could also be
+      // misinterpreted as an index in this corner case.  Oh well.
+      size_t
+      _M_do_find_first(size_t) const _GLIBCXX_NOEXCEPT
+      { return 0; }
+
+      size_t
+      _M_do_find_next(size_t, size_t) const _GLIBCXX_NOEXCEPT
+      { return 0; }
+    };
+
+
+  // Helper class to zero out the unused high-order bits in the highest word.
+  template<size_t _Extrabits>
+    struct _Sanitize
+    {
+      typedef unsigned long _WordT;
+
+      static void
+      _S_do_sanitize(_WordT& __val) _GLIBCXX_NOEXCEPT
+      { __val &= ~((~static_cast<_WordT>(0)) << _Extrabits); }
+    };
+
+  template<>
+    struct _Sanitize<0>
+    {
+      typedef unsigned long _WordT;
+
+      static void
+      _S_do_sanitize(_WordT) _GLIBCXX_NOEXCEPT { }
+    };
+
+#if __cplusplus >= 201103L
+  template<size_t _Nb, bool = (_Nb < _GLIBCXX_BITSET_BITS_PER_ULL)>
+    struct _Sanitize_val
+    {
+      static constexpr unsigned long long
+      _S_do_sanitize_val(unsigned long long __val)
+      { return __val; }
+    };
+
+  template<size_t _Nb>
+    struct _Sanitize_val<_Nb, true>
+    {
+      static constexpr unsigned long long
+      _S_do_sanitize_val(unsigned long long __val)
+      { return __val & ~((~static_cast<unsigned long long>(0)) << _Nb); }
+    };
+#endif
+
+  /**
+   *  @brief The %bitset class represents a @e fixed-size sequence of bits.
+   *  @ingroup utilities
+   *
+   *  (Note that %bitset does @e not meet the formal requirements of a
+   *  <a href="tables.html#65">container</a>.  Mainly, it lacks iterators.)
+   *
+   *  The template argument, @a Nb, may be any non-negative number,
+   *  specifying the number of bits (e.g., "0", "12", "1024*1024").
+   *
+   *  In the general unoptimized case, storage is allocated in word-sized
+   *  blocks.  Let B be the number of bits in a word, then (Nb+(B-1))/B
+   *  words will be used for storage.  B - Nb%B bits are unused.  (They are
+   *  the high-order bits in the highest word.)  It is a class invariant
+   *  that those unused bits are always zero.
+   *
+   *  If you think of %bitset as <em>a simple array of bits</em>, be
+   *  aware that your mental picture is reversed: a %bitset behaves
+   *  the same way as bits in integers do, with the bit at index 0 in
+   *  the <em>least significant / right-hand</em> position, and the bit at
+   *  index Nb-1 in the <em>most significant / left-hand</em> position.
+   *  Thus, unlike other containers, a %bitset's index <em>counts from
+   *  right to left</em>, to put it very loosely.
+   *
+   *  This behavior is preserved when translating to and from strings.  For
+   *  example, the first line of the following program probably prints
+   *  <em>b(&apos;a&apos;) is 0001100001</em> on a modern ASCII system.
+   *
+   *  @code
+   *     #include <bitset>
+   *     #include <iostream>
+   *     #include <sstream>
+   *
+   *     using namespace std;
+   *
+   *     int main()
+   *     {
+   *         long         a = 'a';
+   *         bitset<10>   b(a);
+   *
+   *         cout << "b('a') is " << b << endl;
+   *
+   *         ostringstream s;
+   *         s << b;
+   *         string  str = s.str();
+   *         cout << "index 3 in the string is " << str[3] << " but\n"
+   *              << "index 3 in the bitset is " << b[3] << endl;
+   *     }
+   *  @endcode
+   *
+   *  Also see:
+   *  https://gcc.gnu.org/onlinedocs/libstdc++/manual/ext_containers.html
+   *  for a description of extensions.
+   *
+   *  Most of the actual code isn't contained in %bitset<> itself, but in the
+   *  base class _Base_bitset.  The base class works with whole words, not with
+   *  individual bits.  This allows us to specialize _Base_bitset for the
+   *  important special case where the %bitset is only a single word.
+   *
+   *  Extra confusion can result due to the fact that the storage for
+   *  _Base_bitset @e is a regular array, and is indexed as such.  This is
+   *  carefully encapsulated.
+  */
+  template<size_t _Nb>
+    class bitset
+    : private _Base_bitset<_GLIBCXX_BITSET_WORDS(_Nb)>
+    {
+    private:
+      typedef _Base_bitset<_GLIBCXX_BITSET_WORDS(_Nb)> _Base;
+      typedef unsigned long _WordT;
+
+      template<class _CharT, class _Traits, class _Alloc>
+      void
+      _M_check_initial_position(const std::basic_string<_CharT, _Traits, _Alloc>& __s,
+				size_t __position) const
+      {
+	if (__position > __s.size())
+	  __throw_out_of_range_fmt(__N("bitset::bitset: __position "
+				       "(which is %zu) > __s.size() "
+				       "(which is %zu)"),
+				   __position, __s.size());
+      }
+
+      void _M_check(size_t __position, const char *__s) const
+      {
+	if (__position >= _Nb)
+	  __throw_out_of_range_fmt(__N("%s: __position (which is %zu) "
+				       ">= _Nb (which is %zu)"),
+				   __s, __position, _Nb);
+      }
+
+      void
+      _M_do_sanitize() _GLIBCXX_NOEXCEPT
+      {
+	typedef _Sanitize<_Nb % _GLIBCXX_BITSET_BITS_PER_WORD> __sanitize_type;
+	__sanitize_type::_S_do_sanitize(this->_M_hiword());
+      }
+
+#if __cplusplus >= 201103L
+      friend struct std::hash<bitset>;
+#endif
+
+    public:
+      /**
+       *  This encapsulates the concept of a single bit.  An instance of this
+       *  class is a proxy for an actual bit; this way the individual bit
+       *  operations are done as faster word-size bitwise instructions.
+       *
+       *  Most users will never need to use this class directly; conversions
+       *  to and from bool are automatic and should be transparent.  Overloaded
+       *  operators help to preserve the illusion.
+       *
+       *  (On a typical system, this <em>bit %reference</em> is 64
+       *  times the size of an actual bit.  Ha.)
+       */
+      class reference
+      {
+	friend class bitset;
+
+	_WordT*	_M_wp;
+	size_t 	_M_bpos;
+
+	// left undefined
+	reference();
+
+      public:
+	reference(bitset& __b, size_t __pos) _GLIBCXX_NOEXCEPT
+	{
+	  _M_wp = &__b._M_getword(__pos);
+	  _M_bpos = _Base::_S_whichbit(__pos);
+	}
+
+#if __cplusplus >= 201103L
+	reference(const reference&) = default;
+#endif
+
+	~reference() _GLIBCXX_NOEXCEPT
+	{ }
+
+	// For b[i] = __x;
+	reference&
+	operator=(bool __x) _GLIBCXX_NOEXCEPT
+	{
+	  if (__x)
+	    *_M_wp |= _Base::_S_maskbit(_M_bpos);
+	  else
+	    *_M_wp &= ~_Base::_S_maskbit(_M_bpos);
+	  return *this;
+	}
+
+	// For b[i] = b[__j];
+	reference&
+	operator=(const reference& __j) _GLIBCXX_NOEXCEPT
+	{
+	  if ((*(__j._M_wp) & _Base::_S_maskbit(__j._M_bpos)))
+	    *_M_wp |= _Base::_S_maskbit(_M_bpos);
+	  else
+	    *_M_wp &= ~_Base::_S_maskbit(_M_bpos);
+	  return *this;
+	}
+
+	// Flips the bit
+	bool
+	operator~() const _GLIBCXX_NOEXCEPT
+	{ return (*(_M_wp) & _Base::_S_maskbit(_M_bpos)) == 0; }
+
+	// For __x = b[i];
+	operator bool() const _GLIBCXX_NOEXCEPT
+	{ return (*(_M_wp) & _Base::_S_maskbit(_M_bpos)) != 0; }
+
+	// For b[i].flip();
+	reference&
+	flip() _GLIBCXX_NOEXCEPT
+	{
+	  *_M_wp ^= _Base::_S_maskbit(_M_bpos);
+	  return *this;
+	}
+      };
+      friend class reference;
+
+      // 23.3.5.1 constructors:
+      /// All bits set to zero.
+      _GLIBCXX_CONSTEXPR bitset() _GLIBCXX_NOEXCEPT
+      { }
+
+      /// Initial bits bitwise-copied from a single word (others set to zero).
+#if __cplusplus >= 201103L
+      constexpr bitset(unsigned long long __val) noexcept
+      : _Base(_Sanitize_val<_Nb>::_S_do_sanitize_val(__val)) { }
+#else
+      bitset(unsigned long __val)
+      : _Base(__val)
+      { _M_do_sanitize(); }
+#endif
+
+      /**
+       *  Use a subset of a string.
+       *  @param  __s  A string of @a 0 and @a 1 characters.
+       *  @param  __position  Index of the first character in @a __s to use;
+       *                    defaults to zero.
+       *  @throw  std::out_of_range  If @a pos is bigger the size of @a __s.
+       *  @throw  std::invalid_argument  If a character appears in the string
+       *                                 which is neither @a 0 nor @a 1.
+       */
+      template<class _CharT, class _Traits, class _Alloc>
+	explicit
+	bitset(const std::basic_string<_CharT, _Traits, _Alloc>& __s,
+	       size_t __position = 0)
+	: _Base()
+	{
+	  _M_check_initial_position(__s, __position);
+	  _M_copy_from_string(__s, __position,
+			      std::basic_string<_CharT, _Traits, _Alloc>::npos,
+			      _CharT('0'), _CharT('1'));
+	}
+
+      /**
+       *  Use a subset of a string.
+       *  @param  __s  A string of @a 0 and @a 1 characters.
+       *  @param  __position  Index of the first character in @a __s to use.
+       *  @param  __n    The number of characters to copy.
+       *  @throw std::out_of_range If @a __position is bigger the size
+       *  of @a __s.
+       *  @throw  std::invalid_argument  If a character appears in the string
+       *                                 which is neither @a 0 nor @a 1.
+       */
+      template<class _CharT, class _Traits, class _Alloc>
+	bitset(const std::basic_string<_CharT, _Traits, _Alloc>& __s,
+	       size_t __position, size_t __n)
+	: _Base()
+	{
+	  _M_check_initial_position(__s, __position);
+	  _M_copy_from_string(__s, __position, __n, _CharT('0'), _CharT('1'));
+	}
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 396. what are characters zero and one.
+      template<class _CharT, class _Traits, class _Alloc>
+	bitset(const std::basic_string<_CharT, _Traits, _Alloc>& __s,
+	       size_t __position, size_t __n,
+	       _CharT __zero, _CharT __one = _CharT('1'))
+	: _Base()
+	{
+	  _M_check_initial_position(__s, __position);
+	  _M_copy_from_string(__s, __position, __n, __zero, __one);
+	}
+
+#if __cplusplus >= 201103L
+      /**
+       *  Construct from a character %array.
+       *  @param  __str  An %array of characters @a zero and @a one.
+       *  @param  __n    The number of characters to use.
+       *  @param  __zero The character corresponding to the value 0.
+       *  @param  __one  The character corresponding to the value 1.
+       *  @throw  std::invalid_argument If a character appears in the string
+       *                                which is neither @a __zero nor @a __one.
+       */
+      template<typename _CharT>
+        explicit
+        bitset(const _CharT* __str,
+	       typename std::basic_string<_CharT>::size_type __n
+	       = std::basic_string<_CharT>::npos,
+	       _CharT __zero = _CharT('0'), _CharT __one = _CharT('1'))
+        : _Base()
+        {
+	  if (!__str)
+	    __throw_logic_error(__N("bitset::bitset(const _CharT*, ...)"));
+
+	  if (__n == std::basic_string<_CharT>::npos)
+	    __n = std::char_traits<_CharT>::length(__str);
+	  _M_copy_from_ptr<_CharT, std::char_traits<_CharT>>(__str, __n, 0,
+							     __n, __zero,
+							     __one);
+	}
+#endif
+
+      // 23.3.5.2 bitset operations:
+      ///@{
+      /**
+       *  Operations on bitsets.
+       *  @param  __rhs  A same-sized bitset.
+       *
+       *  These should be self-explanatory.
+       */
+      bitset<_Nb>&
+      operator&=(const bitset<_Nb>& __rhs) _GLIBCXX_NOEXCEPT
+      {
+	this->_M_do_and(__rhs);
+	return *this;
+      }
+
+      bitset<_Nb>&
+      operator|=(const bitset<_Nb>& __rhs) _GLIBCXX_NOEXCEPT
+      {
+	this->_M_do_or(__rhs);
+	return *this;
+      }
+
+      bitset<_Nb>&
+      operator^=(const bitset<_Nb>& __rhs) _GLIBCXX_NOEXCEPT
+      {
+	this->_M_do_xor(__rhs);
+	return *this;
+      }
+      ///@}
+
+      ///@{
+      /**
+       *  Operations on bitsets.
+       *  @param  __position  The number of places to shift.
+       *
+       *  These should be self-explanatory.
+       */
+      bitset<_Nb>&
+      operator<<=(size_t __position) _GLIBCXX_NOEXCEPT
+      {
+	if (__builtin_expect(__position < _Nb, 1))
+	  {
+	    this->_M_do_left_shift(__position);
+	    this->_M_do_sanitize();
+	  }
+	else
+	  this->_M_do_reset();
+	return *this;
+      }
+
+      bitset<_Nb>&
+      operator>>=(size_t __position) _GLIBCXX_NOEXCEPT
+      {
+	if (__builtin_expect(__position < _Nb, 1))
+	  {
+	    this->_M_do_right_shift(__position);
+	    this->_M_do_sanitize();
+	  }
+	else
+	  this->_M_do_reset();
+	return *this;
+      }
+      ///@}
+
+      ///@{
+      /**
+       *  These versions of single-bit set, reset, flip, and test are
+       *  extensions from the SGI version.  They do no range checking.
+       *  @ingroup SGIextensions
+       */
+      bitset<_Nb>&
+      _Unchecked_set(size_t __pos) _GLIBCXX_NOEXCEPT
+      {
+	this->_M_getword(__pos) |= _Base::_S_maskbit(__pos);
+	return *this;
+      }
+
+      bitset<_Nb>&
+      _Unchecked_set(size_t __pos, int __val) _GLIBCXX_NOEXCEPT
+      {
+	if (__val)
+	  this->_M_getword(__pos) |= _Base::_S_maskbit(__pos);
+	else
+	  this->_M_getword(__pos) &= ~_Base::_S_maskbit(__pos);
+	return *this;
+      }
+
+      bitset<_Nb>&
+      _Unchecked_reset(size_t __pos) _GLIBCXX_NOEXCEPT
+      {
+	this->_M_getword(__pos) &= ~_Base::_S_maskbit(__pos);
+	return *this;
+      }
+
+      bitset<_Nb>&
+      _Unchecked_flip(size_t __pos) _GLIBCXX_NOEXCEPT
+      {
+	this->_M_getword(__pos) ^= _Base::_S_maskbit(__pos);
+	return *this;
+      }
+
+      _GLIBCXX_CONSTEXPR bool
+      _Unchecked_test(size_t __pos) const _GLIBCXX_NOEXCEPT
+      { return ((this->_M_getword(__pos) & _Base::_S_maskbit(__pos))
+		!= static_cast<_WordT>(0)); }
+      ///@}
+
+      // Set, reset, and flip.
+      /**
+       *  @brief Sets every bit to true.
+       */
+      bitset<_Nb>&
+      set() _GLIBCXX_NOEXCEPT
+      {
+	this->_M_do_set();
+	this->_M_do_sanitize();
+	return *this;
+      }
+
+      /**
+       *  @brief Sets a given bit to a particular value.
+       *  @param  __position  The index of the bit.
+       *  @param  __val  Either true or false, defaults to true.
+       *  @throw  std::out_of_range  If @a pos is bigger the size of the %set.
+       */
+      bitset<_Nb>&
+      set(size_t __position, bool __val = true)
+      {
+	this->_M_check(__position, __N("bitset::set"));
+	return _Unchecked_set(__position, __val);
+      }
+
+      /**
+       *  @brief Sets every bit to false.
+       */
+      bitset<_Nb>&
+      reset() _GLIBCXX_NOEXCEPT
+      {
+	this->_M_do_reset();
+	return *this;
+      }
+
+      /**
+       *  @brief Sets a given bit to false.
+       *  @param  __position  The index of the bit.
+       *  @throw  std::out_of_range  If @a pos is bigger the size of the %set.
+       *
+       *  Same as writing @c set(pos,false).
+       */
+      bitset<_Nb>&
+      reset(size_t __position)
+      {
+	this->_M_check(__position, __N("bitset::reset"));
+	return _Unchecked_reset(__position);
+      }
+
+      /**
+       *  @brief Toggles every bit to its opposite value.
+       */
+      bitset<_Nb>&
+      flip() _GLIBCXX_NOEXCEPT
+      {
+	this->_M_do_flip();
+	this->_M_do_sanitize();
+	return *this;
+      }
+
+      /**
+       *  @brief Toggles a given bit to its opposite value.
+       *  @param  __position  The index of the bit.
+       *  @throw  std::out_of_range  If @a pos is bigger the size of the %set.
+       */
+      bitset<_Nb>&
+      flip(size_t __position)
+      {
+	this->_M_check(__position, __N("bitset::flip"));
+	return _Unchecked_flip(__position);
+      }
+
+      /// See the no-argument flip().
+      bitset<_Nb>
+      operator~() const _GLIBCXX_NOEXCEPT
+      { return bitset<_Nb>(*this).flip(); }
+
+      ///@{
+      /**
+       *  @brief  Array-indexing support.
+       *  @param  __position  Index into the %bitset.
+       *  @return A bool for a <em>const %bitset</em>.  For non-const
+       *           bitsets, an instance of the reference proxy class.
+       *  @note  These operators do no range checking and throw no exceptions,
+       *         as required by DR 11 to the standard.
+       *
+       *  _GLIBCXX_RESOLVE_LIB_DEFECTS Note that this implementation already
+       *  resolves DR 11 (items 1 and 2), but does not do the range-checking
+       *  required by that DR's resolution.  -pme
+       *  The DR has since been changed:  range-checking is a precondition
+       *  (users' responsibility), and these functions must not throw.  -pme
+       */
+      reference
+      operator[](size_t __position)
+      { return reference(*this, __position); }
+
+      _GLIBCXX_CONSTEXPR bool
+      operator[](size_t __position) const
+      { return _Unchecked_test(__position); }
+      ///@}
+
+      /**
+       *  @brief Returns a numerical interpretation of the %bitset.
+       *  @return  The integral equivalent of the bits.
+       *  @throw  std::overflow_error  If there are too many bits to be
+       *                               represented in an @c unsigned @c long.
+       */
+      unsigned long
+      to_ulong() const
+      { return this->_M_do_to_ulong(); }
+
+#if __cplusplus >= 201103L
+      unsigned long long
+      to_ullong() const
+      { return this->_M_do_to_ullong(); }
+#endif
+
+      /**
+       *  @brief Returns a character interpretation of the %bitset.
+       *  @return  The string equivalent of the bits.
+       *
+       *  Note the ordering of the bits:  decreasing character positions
+       *  correspond to increasing bit positions (see the main class notes for
+       *  an example).
+       */
+      template<class _CharT, class _Traits, class _Alloc>
+	std::basic_string<_CharT, _Traits, _Alloc>
+	to_string() const
+	{
+	  std::basic_string<_CharT, _Traits, _Alloc> __result;
+	  _M_copy_to_string(__result, _CharT('0'), _CharT('1'));
+	  return __result;
+	}
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 396. what are characters zero and one.
+      template<class _CharT, class _Traits, class _Alloc>
+	std::basic_string<_CharT, _Traits, _Alloc>
+	to_string(_CharT __zero, _CharT __one = _CharT('1')) const
+	{
+	  std::basic_string<_CharT, _Traits, _Alloc> __result;
+	  _M_copy_to_string(__result, __zero, __one);
+	  return __result;
+	}
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 434. bitset::to_string() hard to use.
+      template<class _CharT, class _Traits>
+	std::basic_string<_CharT, _Traits, std::allocator<_CharT> >
+	to_string() const
+	{ return to_string<_CharT, _Traits, std::allocator<_CharT> >(); }
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 853. to_string needs updating with zero and one.
+      template<class _CharT, class _Traits>
+	std::basic_string<_CharT, _Traits, std::allocator<_CharT> >
+	to_string(_CharT __zero, _CharT __one = _CharT('1')) const
+	{ return to_string<_CharT, _Traits,
+	                   std::allocator<_CharT> >(__zero, __one); }
+
+      template<class _CharT>
+	std::basic_string<_CharT, std::char_traits<_CharT>,
+	                  std::allocator<_CharT> >
+	to_string() const
+	{
+	  return to_string<_CharT, std::char_traits<_CharT>,
+	                   std::allocator<_CharT> >();
+	}
+
+      template<class _CharT>
+	std::basic_string<_CharT, std::char_traits<_CharT>,
+	                  std::allocator<_CharT> >
+	to_string(_CharT __zero, _CharT __one = _CharT('1')) const
+	{
+	  return to_string<_CharT, std::char_traits<_CharT>,
+	                   std::allocator<_CharT> >(__zero, __one);
+	}
+
+      std::basic_string<char, std::char_traits<char>, std::allocator<char> >
+      to_string() const
+      {
+	return to_string<char, std::char_traits<char>,
+	                 std::allocator<char> >();
+      }
+
+      std::basic_string<char, std::char_traits<char>, std::allocator<char> >
+      to_string(char __zero, char __one = '1') const
+      {
+	return to_string<char, std::char_traits<char>,
+	                 std::allocator<char> >(__zero, __one);
+      }
+
+      // Helper functions for string operations.
+      template<class _CharT, class _Traits>
+        void
+        _M_copy_from_ptr(const _CharT*, size_t, size_t, size_t,
+			 _CharT, _CharT);
+
+      template<class _CharT, class _Traits, class _Alloc>
+	void
+	_M_copy_from_string(const std::basic_string<_CharT,
+			    _Traits, _Alloc>& __s, size_t __pos, size_t __n,
+			    _CharT __zero, _CharT __one)
+	{ _M_copy_from_ptr<_CharT, _Traits>(__s.data(), __s.size(), __pos, __n,
+					    __zero, __one); }
+
+      template<class _CharT, class _Traits, class _Alloc>
+	void
+        _M_copy_to_string(std::basic_string<_CharT, _Traits, _Alloc>&,
+			  _CharT, _CharT) const;
+
+      // NB: Backward compat.
+      template<class _CharT, class _Traits, class _Alloc>
+	void
+	_M_copy_from_string(const std::basic_string<_CharT,
+			    _Traits, _Alloc>& __s, size_t __pos, size_t __n)
+	{ _M_copy_from_string(__s, __pos, __n, _CharT('0'), _CharT('1')); }
+
+      template<class _CharT, class _Traits, class _Alloc>
+	void
+        _M_copy_to_string(std::basic_string<_CharT, _Traits,_Alloc>& __s) const
+	{ _M_copy_to_string(__s, _CharT('0'), _CharT('1')); }
+
+      /// Returns the number of bits which are set.
+      size_t
+      count() const _GLIBCXX_NOEXCEPT
+      { return this->_M_do_count(); }
+
+      /// Returns the total number of bits.
+      _GLIBCXX_CONSTEXPR size_t
+      size() const _GLIBCXX_NOEXCEPT
+      { return _Nb; }
+
+      ///@{
+      /// These comparisons for equality/inequality are, well, @e bitwise.
+      bool
+      operator==(const bitset<_Nb>& __rhs) const _GLIBCXX_NOEXCEPT
+      { return this->_M_is_equal(__rhs); }
+
+#if __cpp_impl_three_way_comparison < 201907L
+      bool
+      operator!=(const bitset<_Nb>& __rhs) const _GLIBCXX_NOEXCEPT
+      { return !this->_M_is_equal(__rhs); }
+#endif
+      ///@}
+
+      /**
+       *  @brief Tests the value of a bit.
+       *  @param  __position  The index of a bit.
+       *  @return  The value at @a pos.
+       *  @throw  std::out_of_range  If @a pos is bigger the size of the %set.
+       */
+      bool
+      test(size_t __position) const
+      {
+	this->_M_check(__position, __N("bitset::test"));
+	return _Unchecked_test(__position);
+      }
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // DR 693. std::bitset::all() missing.
+      /**
+       *  @brief Tests whether all the bits are on.
+       *  @return  True if all the bits are set.
+       */
+      bool
+      all() const _GLIBCXX_NOEXCEPT
+      { return this->template _M_are_all<_Nb>(); }
+
+      /**
+       *  @brief Tests whether any of the bits are on.
+       *  @return  True if at least one bit is set.
+       */
+      bool
+      any() const _GLIBCXX_NOEXCEPT
+      { return this->_M_is_any(); }
+
+      /**
+       *  @brief Tests whether any of the bits are on.
+       *  @return  True if none of the bits are set.
+       */
+      bool
+      none() const _GLIBCXX_NOEXCEPT
+      { return !this->_M_is_any(); }
+
+      ///@{
+      /// Self-explanatory.
+      bitset<_Nb>
+      operator<<(size_t __position) const _GLIBCXX_NOEXCEPT
+      { return bitset<_Nb>(*this) <<= __position; }
+
+      bitset<_Nb>
+      operator>>(size_t __position) const _GLIBCXX_NOEXCEPT
+      { return bitset<_Nb>(*this) >>= __position; }
+      ///@}
+
+      /**
+       *  @brief  Finds the index of the first "on" bit.
+       *  @return  The index of the first bit set, or size() if not found.
+       *  @ingroup SGIextensions
+       *  @sa  _Find_next
+       */
+      size_t
+      _Find_first() const _GLIBCXX_NOEXCEPT
+      { return this->_M_do_find_first(_Nb); }
+
+      /**
+       *  @brief  Finds the index of the next "on" bit after prev.
+       *  @return  The index of the next bit set, or size() if not found.
+       *  @param  __prev  Where to start searching.
+       *  @ingroup SGIextensions
+       *  @sa  _Find_first
+       */
+      size_t
+      _Find_next(size_t __prev) const _GLIBCXX_NOEXCEPT
+      { return this->_M_do_find_next(__prev, _Nb); }
+    };
+
+  // Definitions of non-inline member functions.
+  template<size_t _Nb>
+    template<class _CharT, class _Traits>
+      void
+      bitset<_Nb>::
+      _M_copy_from_ptr(const _CharT* __s, size_t __len,
+		       size_t __pos, size_t __n, _CharT __zero, _CharT __one)
+      {
+	reset();
+	const size_t __nbits = std::min(_Nb, std::min(__n, size_t(__len - __pos)));
+	for (size_t __i = __nbits; __i > 0; --__i)
+	  {
+	    const _CharT __c = __s[__pos + __nbits - __i];
+	    if (_Traits::eq(__c, __zero))
+	      ;
+	    else if (_Traits::eq(__c, __one))
+	      _Unchecked_set(__i - 1);
+	    else
+	      __throw_invalid_argument(__N("bitset::_M_copy_from_ptr"));
+	  }
+      }
+
+  template<size_t _Nb>
+    template<class _CharT, class _Traits, class _Alloc>
+      void
+      bitset<_Nb>::
+      _M_copy_to_string(std::basic_string<_CharT, _Traits, _Alloc>& __s,
+			_CharT __zero, _CharT __one) const
+      {
+	__s.assign(_Nb, __zero);
+	for (size_t __i = _Nb; __i > 0; --__i)
+	  if (_Unchecked_test(__i - 1))
+	    _Traits::assign(__s[_Nb - __i], __one);
+      }
+
+  // 23.3.5.3 bitset operations:
+  ///@{
+  /**
+   *  @brief  Global bitwise operations on bitsets.
+   *  @param  __x  A bitset.
+   *  @param  __y  A bitset of the same size as @a __x.
+   *  @return  A new bitset.
+   *
+   *  These should be self-explanatory.
+  */
+  template<size_t _Nb>
+    inline bitset<_Nb>
+    operator&(const bitset<_Nb>& __x, const bitset<_Nb>& __y) _GLIBCXX_NOEXCEPT
+    {
+      bitset<_Nb> __result(__x);
+      __result &= __y;
+      return __result;
+    }
+
+  template<size_t _Nb>
+    inline bitset<_Nb>
+    operator|(const bitset<_Nb>& __x, const bitset<_Nb>& __y) _GLIBCXX_NOEXCEPT
+    {
+      bitset<_Nb> __result(__x);
+      __result |= __y;
+      return __result;
+    }
+
+  template <size_t _Nb>
+    inline bitset<_Nb>
+    operator^(const bitset<_Nb>& __x, const bitset<_Nb>& __y) _GLIBCXX_NOEXCEPT
+    {
+      bitset<_Nb> __result(__x);
+      __result ^= __y;
+      return __result;
+    }
+  ///@}
+
+  ///@{
+  /**
+   *  @brief Global I/O operators for bitsets.
+   *
+   *  Direct I/O between streams and bitsets is supported.  Output is
+   *  straightforward.  Input will skip whitespace, only accept @a 0 and @a 1
+   *  characters, and will only extract as many digits as the %bitset will
+   *  hold.
+  */
+  template<class _CharT, class _Traits, size_t _Nb>
+    std::basic_istream<_CharT, _Traits>&
+    operator>>(std::basic_istream<_CharT, _Traits>& __is, bitset<_Nb>& __x)
+    {
+      typedef typename _Traits::char_type          char_type;
+      typedef std::basic_istream<_CharT, _Traits>  __istream_type;
+      typedef typename __istream_type::ios_base    __ios_base;
+
+      std::basic_string<_CharT, _Traits> __tmp;
+      __tmp.reserve(_Nb);
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 303. Bitset input operator underspecified
+      const char_type __zero = __is.widen('0');
+      const char_type __one = __is.widen('1');
+
+      typename __ios_base::iostate __state = __ios_base::goodbit;
+      typename __istream_type::sentry __sentry(__is);
+      if (__sentry)
+	{
+	  __try
+	    {
+	      for (size_t __i = _Nb; __i > 0; --__i)
+		{
+		  static typename _Traits::int_type __eof = _Traits::eof();
+
+		  typename _Traits::int_type __c1 = __is.rdbuf()->sbumpc();
+		  if (_Traits::eq_int_type(__c1, __eof))
+		    {
+		      __state |= __ios_base::eofbit;
+		      break;
+		    }
+		  else
+		    {
+		      const char_type __c2 = _Traits::to_char_type(__c1);
+		      if (_Traits::eq(__c2, __zero))
+			__tmp.push_back(__zero);
+		      else if (_Traits::eq(__c2, __one))
+			__tmp.push_back(__one);
+		      else if (_Traits::
+			       eq_int_type(__is.rdbuf()->sputbackc(__c2),
+					   __eof))
+			{
+			  __state |= __ios_base::failbit;
+			  break;
+			}
+		    }
+		}
+	    }
+	  __catch(__cxxabiv1::__forced_unwind&)
+	    {
+	      __is._M_setstate(__ios_base::badbit);
+	      __throw_exception_again;
+	    }
+	  __catch(...)
+	    { __is._M_setstate(__ios_base::badbit); }
+	}
+
+      if (__tmp.empty() && _Nb)
+	__state |= __ios_base::failbit;
+      else
+	__x._M_copy_from_string(__tmp, static_cast<size_t>(0), _Nb,
+				__zero, __one);
+      if (__state)
+	__is.setstate(__state);
+      return __is;
+    }
+
+  template <class _CharT, class _Traits, size_t _Nb>
+    std::basic_ostream<_CharT, _Traits>&
+    operator<<(std::basic_ostream<_CharT, _Traits>& __os,
+	       const bitset<_Nb>& __x)
+    {
+      std::basic_string<_CharT, _Traits> __tmp;
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 396. what are characters zero and one.
+      const ctype<_CharT>& __ct = use_facet<ctype<_CharT> >(__os.getloc());
+      __x._M_copy_to_string(__tmp, __ct.widen('0'), __ct.widen('1'));
+      return __os << __tmp;
+    }
+  ///@}
+
+_GLIBCXX_END_NAMESPACE_CONTAINER
+} // namespace std
+
+#undef _GLIBCXX_BITSET_WORDS
+#undef _GLIBCXX_BITSET_BITS_PER_WORD
+#undef _GLIBCXX_BITSET_BITS_PER_ULL
+
+#if __cplusplus >= 201103L
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  // DR 1182.
+  /// std::hash specialization for bitset.
+  template<size_t _Nb>
+    struct hash<_GLIBCXX_STD_C::bitset<_Nb>>
+    : public __hash_base<size_t, _GLIBCXX_STD_C::bitset<_Nb>>
+    {
+      size_t
+      operator()(const _GLIBCXX_STD_C::bitset<_Nb>& __b) const noexcept
+      {
+	const size_t __clength = (_Nb + __CHAR_BIT__ - 1) / __CHAR_BIT__;
+	return std::_Hash_impl::hash(__b._M_getdata(), __clength);
+      }
+    };
+
+  template<>
+    struct hash<_GLIBCXX_STD_C::bitset<0>>
+    : public __hash_base<size_t, _GLIBCXX_STD_C::bitset<0>>
+    {
+      size_t
+      operator()(const _GLIBCXX_STD_C::bitset<0>&) const noexcept
+      { return 0; }
+    };
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif // C++11
+
+#ifdef _GLIBCXX_DEBUG
+# include <debug/bitset>
+#endif
+
+#endif /* _GLIBCXX_BITSET */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bitset.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@bitset.blob
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new file mode 100644
index 0000000000000000000000000000000000000000..9f525c6d1f4b833130514360627885f7ac0c5035
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@cassert
@@ -0,0 +1,44 @@
+// -*- C++ -*- forwarding header.
+
+// Copyright (C) 1997-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file cassert
+ *  This is a Standard C++ Library file.  You should @c \#include this file
+ *  in your programs, rather than any of the @a *.h implementation files.
+ *
+ *  This is the C++ version of the Standard C Library header @c assert.h,
+ *  and its contents are (mostly) the same as that header, but are all
+ *  contained in the namespace @c std (except for names which are defined
+ *  as macros in C).
+ */
+
+//
+// ISO C++ 14882: 19.2  Assertions
+//
+
+// No include guards on this header...
+
+#pragma GCC system_header
+
+#include <bits/c++config.h>
+#include <assert.h>
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@ccomplex b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@ccomplex
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--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@ccomplex
@@ -0,0 +1,42 @@
+// <ccomplex> -*- C++ -*-
+
+// Copyright (C) 2007-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file include/ccomplex
+ *  This is a Standard C++ Library header.
+ */
+
+#pragma GCC system_header
+
+#ifndef _GLIBCXX_CCOMPLEX
+#define _GLIBCXX_CCOMPLEX 1
+
+#if __cplusplus < 201103L
+# include <bits/c++0x_warning.h>
+#endif
+
+extern "C++" {
+#include <complex>
+}
+
+#endif
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@cctype b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@cctype
new file mode 100644
index 0000000000000000000000000000000000000000..b7af41a182f962aa2cc823f03d38e45ebe27984a
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@cctype
@@ -0,0 +1,94 @@
+// -*- C++ -*- forwarding header.
+
+// Copyright (C) 1997-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file include/cctype
+ *  This is a Standard C++ Library file.  You should @c \#include this file
+ *  in your programs, rather than any of the @a *.h implementation files.
+ *
+ *  This is the C++ version of the Standard C Library header @c ctype.h,
+ *  and its contents are (mostly) the same as that header, but are all
+ *  contained in the namespace @c std (except for names which are defined
+ *  as macros in C).
+ */
+
+//
+// ISO C++ 14882: <ccytpe>
+//
+
+#pragma GCC system_header
+
+#include <bits/c++config.h>
+#include <ctype.h>
+
+#ifndef _GLIBCXX_CCTYPE
+#define _GLIBCXX_CCTYPE 1
+
+// Get rid of those macros defined in <ctype.h> in lieu of real functions.
+#undef isalnum
+#undef isalpha
+#undef iscntrl
+#undef isdigit
+#undef isgraph
+#undef islower
+#undef isprint
+#undef ispunct
+#undef isspace
+#undef isupper
+#undef isxdigit
+#undef tolower
+#undef toupper
+
+namespace std
+{
+  using ::isalnum;
+  using ::isalpha;
+  using ::iscntrl;
+  using ::isdigit;
+  using ::isgraph;
+  using ::islower;
+  using ::isprint;
+  using ::ispunct;
+  using ::isspace;
+  using ::isupper;
+  using ::isxdigit;
+  using ::tolower;
+  using ::toupper;
+} // namespace std
+
+#if __cplusplus >= 201103L
+
+#ifdef _GLIBCXX_USE_C99_CTYPE_TR1
+
+#undef isblank
+
+namespace std
+{
+  using ::isblank;
+} // namespace std
+
+#endif // _GLIBCXX_USE_C99_CTYPE_TR1
+
+#endif // C++11
+
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@cctype.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@cctype.blob
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new file mode 100644
index 0000000000000000000000000000000000000000..afaeae68a6106d9de39158fe6138eee2313bd853
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@cerrno
@@ -0,0 +1,52 @@
+// The -*- C++ -*- forwarding header.
+
+// Copyright (C) 1997-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file cerrno
+ *  This is a Standard C++ Library file.  You should @c \#include this file
+ *  in your programs, rather than any of the @a *.h implementation files.
+ *
+ *  This is the C++ version of the Standard C Library header @c errno.h,
+ *  and its contents are (mostly) the same as that header, but are all
+ *  contained in the namespace @c std (except for names which are defined
+ *  as macros in C).
+ */
+
+//
+// ISO C++ 14882: 19.3  Error numbers
+//
+
+#pragma GCC system_header
+
+#include <bits/c++config.h>
+#include <errno.h>
+
+#ifndef _GLIBCXX_CERRNO
+#define _GLIBCXX_CERRNO 1
+
+// Adhere to section 17.4.1.2 clause 5 of ISO 14882:1998
+#ifndef errno
+#define errno errno
+#endif
+
+#endif
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@cfenv b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@cfenv
new file mode 100644
index 0000000000000000000000000000000000000000..d415d47ea4583dec543988e2a85f67a1548b30ac
--- /dev/null
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@@ -0,0 +1,84 @@
+// <cfenv> -*- C++ -*-
+
+// Copyright (C) 2007-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file include/cfenv
+ *  This is a Standard C++ Library header.
+ */
+
+#ifndef _GLIBCXX_CFENV
+#define _GLIBCXX_CFENV 1
+
+#pragma GCC system_header
+
+#if __cplusplus < 201103L
+# include <bits/c++0x_warning.h>
+#else
+
+#include <bits/c++config.h>
+
+#if _GLIBCXX_HAVE_FENV_H
+# include <fenv.h>
+#endif
+
+#ifdef _GLIBCXX_USE_C99_FENV_TR1
+
+#undef feclearexcept
+#undef fegetexceptflag
+#undef feraiseexcept
+#undef fesetexceptflag
+#undef fetestexcept
+#undef fegetround
+#undef fesetround
+#undef fegetenv
+#undef feholdexcept
+#undef fesetenv
+#undef feupdateenv
+
+namespace std
+{
+  // types
+  using ::fenv_t;
+  using ::fexcept_t;
+
+  // functions
+  using ::feclearexcept;
+  using ::fegetexceptflag;
+  using ::feraiseexcept;
+  using ::fesetexceptflag;
+  using ::fetestexcept;
+
+  using ::fegetround;
+  using ::fesetround;
+
+  using ::fegetenv;
+  using ::feholdexcept;
+  using ::fesetenv;
+  using ::feupdateenv;
+} // namespace std
+
+#endif // _GLIBCXX_USE_C99_FENV_TR1
+
+#endif // C++11
+
+#endif // _GLIBCXX_CFENV
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@@ -0,0 +1,56 @@
+// -*- C++ -*- forwarding header.
+
+// Copyright (C) 1997-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file include/cfloat
+ *  This is a Standard C++ Library file.  You should @c \#include this file
+ *  in your programs, rather than any of the @a *.h implementation files.
+ *
+ *  This is the C++ version of the Standard C Library header @c float.h,
+ *  and its contents are (mostly) the same as that header, but are all
+ *  contained in the namespace @c std (except for names which are defined
+ *  as macros in C).
+ */
+
+//
+// ISO C++ 14882: 18.2.2  Implementation properties: C library
+//
+
+#pragma GCC system_header
+
+#include <bits/c++config.h>
+#include <float.h>
+
+#ifndef _GLIBCXX_CFLOAT
+#define _GLIBCXX_CFLOAT 1
+
+#if __cplusplus >= 201103L
+#  ifndef DECIMAL_DIG
+#    define DECIMAL_DIG __DECIMAL_DIG__
+#  endif
+#  ifndef FLT_EVAL_METHOD
+#    define FLT_EVAL_METHOD __FLT_EVAL_METHOD__
+#  endif
+#endif
+
+#endif
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+// <chrono> -*- C++ -*-
+
+// Copyright (C) 2008-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file include/chrono
+ *  This is a Standard C++ Library header.
+ *  @ingroup chrono
+ */
+
+#ifndef _GLIBCXX_CHRONO
+#define _GLIBCXX_CHRONO 1
+
+#pragma GCC system_header
+
+#if __cplusplus < 201103L
+# include <bits/c++0x_warning.h>
+#else
+
+#include <bits/chrono.h>
+#if __cplusplus > 201703L
+# include <sstream> // ostringstream
+# include <bits/charconv.h>
+#endif
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /**
+   * @defgroup chrono Time
+   * @ingroup utilities
+   *
+   * Classes and functions for time.
+   *
+   * @since C++11
+   */
+
+  /** @namespace std::chrono
+   *  @brief ISO C++ 2011 namespace for date and time utilities
+   *  @ingroup chrono
+   */
+  namespace chrono
+  {
+#if __cplusplus >= 202002L
+    /// @addtogroup chrono
+    /// @{
+    struct local_t { };
+    template<typename _Duration>
+      using local_time = time_point<local_t, _Duration>;
+    using local_seconds = local_time<seconds>;
+    using local_days = local_time<days>;
+
+    class utc_clock;
+    class tai_clock;
+    class gps_clock;
+
+    template<typename _Duration>
+      using utc_time = time_point<utc_clock, _Duration>;
+    using utc_seconds = utc_time<seconds>;
+
+    template<typename _Duration>
+      using tai_time = time_point<tai_clock, _Duration>;
+    using tai_seconds = tai_time<seconds>;
+
+    template<typename _Duration>
+      using gps_time = time_point<gps_clock, _Duration>;
+    using gps_seconds = gps_time<seconds>;
+
+    template<> struct is_clock<utc_clock> : true_type { };
+    template<> struct is_clock<tai_clock> : true_type { };
+    template<> struct is_clock<gps_clock> : true_type { };
+
+    template<> inline constexpr bool is_clock_v<utc_clock> = true;
+    template<> inline constexpr bool is_clock_v<tai_clock> = true;
+    template<> inline constexpr bool is_clock_v<gps_clock> = true;
+
+    struct leap_second_info
+    {
+      bool is_leap_second;
+      seconds elapsed;
+    };
+
+    // CALENDRICAL TYPES
+
+    // CLASS DECLARATIONS
+    class day;
+    class month;
+    class year;
+    class weekday;
+    class weekday_indexed;
+    class weekday_last;
+    class month_day;
+    class month_day_last;
+    class month_weekday;
+    class month_weekday_last;
+    class year_month;
+    class year_month_day;
+    class year_month_day_last;
+    class year_month_weekday;
+    class year_month_weekday_last;
+
+    struct last_spec
+    {
+      explicit last_spec() = default;
+
+      friend constexpr month_day_last
+      operator/(int __m, last_spec) noexcept;
+
+      friend constexpr month_day_last
+      operator/(last_spec, int __m) noexcept;
+    };
+
+    inline constexpr last_spec last{};
+
+    namespace __detail
+    {
+      // Compute the remainder of the Euclidean division of __n divided by __d.
+      // Euclidean division truncates toward negative infinity and always
+      // produces a remainder in the range of [0,__d-1] (whereas standard
+      // division truncates toward zero and yields a nonpositive remainder
+      // for negative __n).
+      constexpr unsigned
+      __modulo(long long __n, unsigned __d)
+      {
+	if (__n >= 0)
+	  return __n % __d;
+	else
+	  return (__d + (__n % __d)) % __d;
+      }
+
+      inline constexpr unsigned __days_per_month[12]
+	= { 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
+    }
+
+    // DAY
+
+    class day
+    {
+    private:
+      unsigned char _M_d;
+
+    public:
+      day() = default;
+
+      explicit constexpr
+      day(unsigned __d) noexcept
+      : _M_d(__d)
+      { }
+
+      constexpr day&
+      operator++() noexcept
+      {
+	++_M_d;
+	return *this;
+      }
+
+      constexpr day
+      operator++(int) noexcept
+      {
+	auto __ret = *this;
+	++(*this);
+	return __ret;
+      }
+
+      constexpr day&
+      operator--() noexcept
+      {
+	--_M_d;
+	return *this;
+      }
+
+      constexpr day
+      operator--(int) noexcept
+      {
+	auto __ret = *this;
+	--(*this);
+	return __ret;
+      }
+
+      constexpr day&
+      operator+=(const days& __d) noexcept
+      {
+	*this = *this + __d;
+	return *this;
+      }
+
+      constexpr day&
+      operator-=(const days& __d) noexcept
+      {
+	*this = *this - __d;
+	return *this;
+      }
+
+      constexpr explicit
+      operator unsigned() const noexcept
+      { return _M_d; }
+
+      constexpr bool
+      ok() const noexcept
+      { return 1 <= _M_d && _M_d <= 31; }
+
+      friend constexpr bool
+      operator==(const day& __x, const day& __y) noexcept
+      { return unsigned{__x} == unsigned{__y}; }
+
+      friend constexpr strong_ordering
+      operator<=>(const day& __x, const day& __y) noexcept
+      { return unsigned{__x} <=> unsigned{__y}; }
+
+      friend constexpr day
+      operator+(const day& __x, const days& __y) noexcept
+      { return day(unsigned{__x} + __y.count()); }
+
+      friend constexpr day
+      operator+(const days& __x, const day& __y) noexcept
+      { return __y + __x; }
+
+      friend constexpr day
+      operator-(const day& __x, const days& __y) noexcept
+      { return __x + -__y; }
+
+      friend constexpr days
+      operator-(const day& __x, const day& __y) noexcept
+      { return days{int(unsigned{__x}) - int(unsigned{__y})}; }
+
+      friend constexpr month_day
+      operator/(const month& __m, const day& __d) noexcept;
+
+      friend constexpr month_day
+      operator/(int __m, const day& __d) noexcept;
+
+      friend constexpr month_day
+      operator/(const day& __d, const month& __m) noexcept;
+
+      friend constexpr month_day
+      operator/(const day& __d, int __m) noexcept;
+
+      friend constexpr year_month_day
+      operator/(const year_month& __ym, const day& __d) noexcept;
+
+      // TODO: Implement operator<<, to_stream, from_stream.
+    };
+
+    // MONTH
+
+    class month
+    {
+    private:
+      unsigned char _M_m;
+
+    public:
+      month() = default;
+
+      explicit constexpr
+      month(unsigned __m) noexcept
+      : _M_m(__m)
+      { }
+
+      constexpr month&
+      operator++() noexcept
+      {
+	*this += months{1};
+	return *this;
+      }
+
+      constexpr month
+      operator++(int) noexcept
+      {
+	auto __ret = *this;
+	++(*this);
+	return __ret;
+      }
+
+      constexpr month&
+      operator--() noexcept
+      {
+	*this -= months{1};
+	return *this;
+      }
+
+      constexpr month
+      operator--(int) noexcept
+      {
+	auto __ret = *this;
+	--(*this);
+	return __ret;
+      }
+
+      constexpr month&
+      operator+=(const months& __m) noexcept
+      {
+	*this = *this + __m;
+	return *this;
+      }
+
+      constexpr month&
+      operator-=(const months& __m) noexcept
+      {
+	*this = *this - __m;
+	return *this;
+      }
+
+      explicit constexpr
+      operator unsigned() const noexcept
+      { return _M_m; }
+
+      constexpr bool
+      ok() const noexcept
+      { return 1 <= _M_m && _M_m <= 12; }
+
+      friend constexpr bool
+      operator==(const month& __x, const month& __y) noexcept
+      { return unsigned{__x} == unsigned{__y}; }
+
+      friend constexpr strong_ordering
+      operator<=>(const month& __x, const month& __y) noexcept
+      { return unsigned{__x} <=> unsigned{__y}; }
+
+      friend constexpr month
+      operator+(const month& __x, const months& __y) noexcept
+      {
+	auto __n = static_cast<long long>(unsigned{__x}) + (__y.count() - 1);
+	return month{__detail::__modulo(__n, 12) + 1};
+      }
+
+      friend constexpr month
+      operator+(const months& __x,  const month& __y) noexcept
+      { return __y + __x; }
+
+      friend constexpr month
+      operator-(const month& __x, const months& __y) noexcept
+      { return __x + -__y; }
+
+      friend constexpr months
+      operator-(const month& __x,  const month& __y) noexcept
+      {
+	const auto __dm = int(unsigned(__x)) - int(unsigned(__y));
+	return months{__dm < 0 ? 12 + __dm : __dm};
+      }
+
+      friend constexpr year_month
+      operator/(const year& __y, const month& __m) noexcept;
+
+      friend constexpr month_day
+      operator/(const month& __m, int __d) noexcept;
+
+      friend constexpr month_day_last
+      operator/(const month& __m, last_spec) noexcept;
+
+      friend constexpr month_day_last
+      operator/(last_spec, const month& __m) noexcept;
+
+      friend constexpr month_weekday
+      operator/(const month& __m, const weekday_indexed& __wdi) noexcept;
+
+      friend constexpr month_weekday
+      operator/(const weekday_indexed& __wdi, const month& __m) noexcept;
+
+      friend constexpr month_weekday_last
+      operator/(const month& __m, const weekday_last& __wdl) noexcept;
+
+      friend constexpr month_weekday_last
+      operator/(const weekday_last& __wdl, const month& __m) noexcept;
+
+      // TODO: Implement operator<<, to_stream, from_stream.
+    };
+
+    inline constexpr month January{1};
+    inline constexpr month February{2};
+    inline constexpr month March{3};
+    inline constexpr month April{4};
+    inline constexpr month May{5};
+    inline constexpr month June{6};
+    inline constexpr month July{7};
+    inline constexpr month August{8};
+    inline constexpr month September{9};
+    inline constexpr month October{10};
+    inline constexpr month November{11};
+    inline constexpr month December{12};
+
+    // YEAR
+
+    class year
+    {
+    private:
+      short _M_y;
+
+    public:
+      year() = default;
+
+      explicit constexpr
+      year(int __y) noexcept
+      : _M_y{static_cast<short>(__y)}
+      { }
+
+      static constexpr year
+      min() noexcept
+      { return year{-32767}; }
+
+      static constexpr year
+      max() noexcept
+      { return year{32767}; }
+
+      constexpr year&
+      operator++() noexcept
+      {
+	++_M_y;
+	return *this;
+      }
+
+      constexpr year
+      operator++(int) noexcept
+      {
+	auto __ret = *this;
+	++(*this);
+	return __ret;
+      }
+
+      constexpr year&
+      operator--() noexcept
+      {
+	--_M_y;
+	return *this;
+      }
+
+      constexpr year
+      operator--(int) noexcept
+      {
+	auto __ret = *this;
+	--(*this);
+	return __ret;
+      }
+
+      constexpr year&
+      operator+=(const years& __y) noexcept
+      {
+	*this = *this + __y;
+	return *this;
+      }
+
+      constexpr year&
+      operator-=(const years& __y) noexcept
+      {
+	*this = *this - __y;
+	return *this;
+      }
+
+      constexpr year
+      operator+() const noexcept
+      { return *this; }
+
+      constexpr year
+      operator-() const noexcept
+      { return year{-_M_y}; }
+
+      constexpr bool
+      is_leap() const noexcept
+      {
+	// Testing divisibility by 100 first gives better performance, that is,
+	// return (_M_y % 100 != 0 || _M_y % 400 == 0) && _M_y % 4 == 0;
+
+	// It gets even faster if _M_y is in [-536870800, 536870999]
+	// (which is the case here) and _M_y % 100 is replaced by
+	// __is_multiple_of_100 below.
+
+	// References:
+	// [1] https://github.com/cassioneri/calendar
+	// [2] https://accu.org/journals/overload/28/155/overload155.pdf#page=16
+
+	// Furthermore, if y%100 == 0, then y%400==0 is equivalent to y%16==0,
+	// so we can simplify it to (!mult_100 && y % 4 == 0) || y % 16 == 0,
+	// which is equivalent to (y & (mult_100 ? 15 : 3)) == 0.
+	// See https://gcc.gnu.org/pipermail/libstdc++/2021-June/052815.html
+
+	constexpr uint32_t __multiplier   = 42949673;
+	constexpr uint32_t __bound        = 42949669;
+	constexpr uint32_t __max_dividend = 1073741799;
+	constexpr uint32_t __offset       = __max_dividend / 2 / 100 * 100;
+	const bool __is_multiple_of_100
+	  = __multiplier * (_M_y + __offset) < __bound;
+	return (_M_y & (__is_multiple_of_100 ? 15 : 3)) == 0;
+      }
+
+      explicit constexpr
+      operator int() const noexcept
+      { return _M_y; }
+
+      constexpr bool
+      ok() const noexcept
+      { return min()._M_y <= _M_y && _M_y <= max()._M_y; }
+
+      friend constexpr bool
+      operator==(const year& __x, const year& __y) noexcept
+      { return int{__x} == int{__y}; }
+
+      friend constexpr strong_ordering
+      operator<=>(const year& __x, const year& __y) noexcept
+      { return int{__x} <=> int{__y}; }
+
+      friend constexpr year
+      operator+(const year& __x, const years& __y) noexcept
+      { return year{int{__x} + static_cast<int>(__y.count())}; }
+
+      friend constexpr year
+      operator+(const years& __x, const year& __y) noexcept
+      { return __y + __x; }
+
+      friend constexpr year
+      operator-(const year& __x, const years& __y) noexcept
+      { return __x + -__y; }
+
+      friend constexpr years
+      operator-(const year& __x, const year& __y) noexcept
+      { return years{int{__x} - int{__y}}; }
+
+      friend constexpr year_month
+      operator/(const year& __y, int __m) noexcept;
+
+      friend constexpr year_month_day
+      operator/(const year& __y, const month_day& __md) noexcept;
+
+      friend constexpr year_month_day
+      operator/(const month_day& __md, const year& __y) noexcept;
+
+      friend constexpr year_month_day_last
+      operator/(const year& __y, const month_day_last& __mdl) noexcept;
+
+      friend constexpr year_month_day_last
+      operator/(const month_day_last& __mdl, const year& __y) noexcept;
+
+      friend constexpr year_month_weekday
+      operator/(const year& __y, const month_weekday& __mwd) noexcept;
+
+      friend constexpr year_month_weekday
+      operator/(const month_weekday& __mwd, const year& __y) noexcept;
+
+      friend constexpr year_month_weekday_last
+      operator/(const year& __y, const month_weekday_last& __mwdl) noexcept;
+
+      friend constexpr year_month_weekday_last
+      operator/(const month_weekday_last& __mwdl, const year& __y) noexcept;
+
+      // TODO: Implement operator<<, to_stream, from_stream.
+    };
+
+    // WEEKDAY
+
+    class weekday
+    {
+    private:
+      unsigned char _M_wd;
+
+      static constexpr weekday
+      _S_from_days(const days& __d)
+      {
+	auto __n = __d.count();
+	return weekday(__n >= -4 ? (__n + 4) % 7 : (__n + 5) % 7 + 6);
+      }
+
+    public:
+      weekday() = default;
+
+      explicit constexpr
+      weekday(unsigned __wd) noexcept
+      : _M_wd(__wd == 7 ? 0 : __wd) // __wd % 7 ?
+      { }
+
+      constexpr
+      weekday(const sys_days& __dp) noexcept
+      : weekday{_S_from_days(__dp.time_since_epoch())}
+      { }
+
+      explicit constexpr
+      weekday(const local_days& __dp) noexcept
+      : weekday{sys_days{__dp.time_since_epoch()}}
+      { }
+
+      constexpr weekday&
+      operator++() noexcept
+      {
+	*this += days{1};
+	return *this;
+      }
+
+      constexpr weekday
+      operator++(int) noexcept
+      {
+	auto __ret = *this;
+	++(*this);
+	return __ret;
+      }
+
+      constexpr weekday&
+      operator--() noexcept
+      {
+	*this -= days{1};
+	return *this;
+      }
+
+      constexpr weekday
+      operator--(int) noexcept
+      {
+	auto __ret = *this;
+	--(*this);
+	return __ret;
+      }
+
+      constexpr weekday&
+      operator+=(const days& __d) noexcept
+      {
+	*this = *this + __d;
+	return *this;
+      }
+
+      constexpr weekday&
+      operator-=(const days& __d) noexcept
+      {
+	*this = *this - __d;
+	return *this;
+      }
+
+      constexpr unsigned
+      c_encoding() const noexcept
+      { return _M_wd; }
+
+      constexpr unsigned
+      iso_encoding() const noexcept
+      { return _M_wd == 0u ? 7u : _M_wd; }
+
+      constexpr bool
+      ok() const noexcept
+      { return _M_wd <= 6; }
+
+      constexpr weekday_indexed
+      operator[](unsigned __index) const noexcept;
+
+      constexpr weekday_last
+      operator[](last_spec) const noexcept;
+
+      friend constexpr bool
+      operator==(const weekday& __x, const weekday& __y) noexcept
+      { return __x._M_wd == __y._M_wd; }
+
+      friend constexpr weekday
+      operator+(const weekday& __x, const days& __y) noexcept
+      {
+	auto __n = static_cast<long long>(__x._M_wd) + __y.count();
+	return weekday{__detail::__modulo(__n, 7)};
+      }
+
+      friend constexpr weekday
+      operator+(const days& __x, const weekday& __y) noexcept
+      { return __y + __x; }
+
+      friend constexpr weekday
+      operator-(const weekday& __x, const days& __y) noexcept
+      { return __x + -__y; }
+
+      friend constexpr days
+      operator-(const weekday& __x, const weekday& __y) noexcept
+      {
+	auto __n = static_cast<long long>(__x._M_wd) - __y._M_wd;
+	return days{__detail::__modulo(__n, 7)};
+      }
+
+      // TODO: operator<<, from_stream.
+    };
+
+    inline constexpr weekday Sunday{0};
+    inline constexpr weekday Monday{1};
+    inline constexpr weekday Tuesday{2};
+    inline constexpr weekday Wednesday{3};
+    inline constexpr weekday Thursday{4};
+    inline constexpr weekday Friday{5};
+    inline constexpr weekday Saturday{6};
+
+    // WEEKDAY_INDEXED
+
+    class weekday_indexed
+    {
+    private:
+      chrono::weekday _M_wd;
+      unsigned char _M_index;
+
+    public:
+      weekday_indexed() = default;
+
+      constexpr
+      weekday_indexed(const chrono::weekday& __wd, unsigned __index) noexcept
+      : _M_wd(__wd), _M_index(__index)
+      { }
+
+      constexpr chrono::weekday
+      weekday() const noexcept
+      { return _M_wd; }
+
+      constexpr unsigned
+      index() const noexcept
+      { return _M_index; };
+
+      constexpr bool
+      ok() const noexcept
+      { return _M_wd.ok() && 1 <= _M_index && _M_index <= 5; }
+
+      friend constexpr bool
+      operator==(const weekday_indexed& __x, const weekday_indexed& __y) noexcept
+      { return __x.weekday() == __y.weekday() && __x.index() == __y.index(); }
+
+      friend constexpr month_weekday
+      operator/(const month& __m, const weekday_indexed& __wdi) noexcept;
+
+      friend constexpr month_weekday
+      operator/(int __m, const weekday_indexed& __wdi) noexcept;
+
+      friend constexpr month_weekday
+      operator/(const weekday_indexed& __wdi, const month& __m) noexcept;
+
+      friend constexpr month_weekday
+      operator/(const weekday_indexed& __wdi, int __m) noexcept;
+
+      friend constexpr year_month_weekday
+      operator/(const year_month& __ym, const weekday_indexed& __wdi) noexcept;
+
+      // TODO: Implement operator<<.
+    };
+
+    constexpr weekday_indexed
+    weekday::operator[](unsigned __index) const noexcept
+    { return {*this, __index}; }
+
+    // WEEKDAY_LAST
+
+    class weekday_last
+    {
+    private:
+      chrono::weekday _M_wd;
+
+    public:
+      explicit constexpr
+      weekday_last(const chrono::weekday& __wd) noexcept
+      : _M_wd{__wd}
+      { }
+
+      constexpr chrono::weekday
+      weekday() const noexcept
+      { return _M_wd; }
+
+      constexpr bool
+      ok() const noexcept
+      { return _M_wd.ok(); }
+
+      friend constexpr bool
+      operator==(const weekday_last& __x, const weekday_last& __y) noexcept
+      { return __x.weekday() == __y.weekday(); }
+
+      friend constexpr month_weekday_last
+      operator/(int __m, const weekday_last& __wdl) noexcept;
+
+      friend constexpr month_weekday_last
+      operator/(const weekday_last& __wdl, int __m) noexcept;
+
+      friend constexpr year_month_weekday_last
+      operator/(const year_month& __ym, const weekday_last& __wdl) noexcept;
+
+      // TODO: Implement operator<<.
+    };
+
+    constexpr weekday_last
+    weekday::operator[](last_spec) const noexcept
+    { return weekday_last{*this}; }
+
+    // MONTH_DAY
+
+    class month_day
+    {
+    private:
+      chrono::month _M_m;
+      chrono::day _M_d;
+
+    public:
+      month_day() = default;
+
+      constexpr
+      month_day(const chrono::month& __m, const chrono::day& __d) noexcept
+      : _M_m{__m}, _M_d{__d}
+      { }
+
+      constexpr chrono::month
+      month() const noexcept
+      { return _M_m; }
+
+      constexpr chrono::day
+      day() const noexcept
+      { return _M_d; }
+
+      constexpr bool
+      ok() const noexcept
+      {
+	return _M_m.ok()
+	  && 1u <= unsigned(_M_d)
+	  && unsigned(_M_d) <= __detail::__days_per_month[unsigned(_M_m) - 1];
+      }
+
+      friend constexpr bool
+      operator==(const month_day& __x, const month_day& __y) noexcept
+      { return __x.month() == __y.month() && __x.day() == __y.day(); }
+
+      friend constexpr strong_ordering
+      operator<=>(const month_day& __x, const month_day& __y) noexcept
+	= default;
+
+      friend constexpr month_day
+      operator/(const chrono::month& __m, const chrono::day& __d) noexcept
+      { return {__m, __d}; }
+
+      friend constexpr month_day
+      operator/(const chrono::month& __m, int __d) noexcept
+      { return {__m, chrono::day(unsigned(__d))}; }
+
+      friend constexpr month_day
+      operator/(int __m, const chrono::day& __d) noexcept
+      { return {chrono::month(unsigned(__m)), __d}; }
+
+      friend constexpr month_day
+      operator/(const chrono::day& __d, const chrono::month& __m) noexcept
+      { return {__m, __d}; }
+
+      friend constexpr month_day
+      operator/(const chrono::day& __d, int __m) noexcept
+      { return {chrono::month(unsigned(__m)), __d}; }
+
+      friend constexpr year_month_day
+      operator/(int __y, const month_day& __md) noexcept;
+
+      friend constexpr year_month_day
+      operator/(const month_day& __md, int __y) noexcept;
+
+      // TODO: Implement operator<<, from_stream.
+    };
+
+    // MONTH_DAY_LAST
+
+    class month_day_last
+    {
+    private:
+      chrono::month _M_m;
+
+    public:
+      explicit constexpr
+      month_day_last(const chrono::month& __m) noexcept
+      : _M_m{__m}
+      { }
+
+      constexpr chrono::month
+      month() const noexcept
+      { return _M_m; }
+
+      constexpr bool
+      ok() const noexcept
+      { return _M_m.ok(); }
+
+      friend constexpr bool
+      operator==(const month_day_last& __x, const month_day_last& __y) noexcept
+      { return __x.month() == __y.month(); }
+
+      friend constexpr strong_ordering
+      operator<=>(const month_day_last& __x, const month_day_last& __y) noexcept
+	= default;
+
+      friend constexpr month_day_last
+      operator/(const chrono::month& __m, last_spec) noexcept
+      { return month_day_last{__m}; }
+
+      friend constexpr month_day_last
+      operator/(int __m, last_spec) noexcept
+      { return chrono::month(unsigned(__m)) / last; }
+
+      friend constexpr month_day_last
+      operator/(last_spec, const chrono::month& __m) noexcept
+      { return __m / last; }
+
+      friend constexpr month_day_last
+      operator/(last_spec, int __m) noexcept
+      { return __m / last; }
+
+      friend constexpr year_month_day_last
+      operator/(int __y, const month_day_last& __mdl) noexcept;
+
+      friend constexpr year_month_day_last
+      operator/(const month_day_last& __mdl, int __y) noexcept;
+
+      // TODO: Implement operator<<.
+    };
+
+    // MONTH_WEEKDAY
+
+    class month_weekday
+    {
+    private:
+      chrono::month _M_m;
+      chrono::weekday_indexed _M_wdi;
+
+    public:
+      constexpr
+      month_weekday(const chrono::month& __m,
+		    const chrono::weekday_indexed& __wdi) noexcept
+      : _M_m{__m}, _M_wdi{__wdi}
+      { }
+
+      constexpr chrono::month
+      month() const noexcept
+      { return _M_m; }
+
+      constexpr chrono::weekday_indexed
+      weekday_indexed() const noexcept
+      { return _M_wdi; }
+
+      constexpr bool
+      ok() const noexcept
+      { return _M_m.ok() && _M_wdi.ok(); }
+
+      friend constexpr bool
+      operator==(const month_weekday& __x, const month_weekday& __y) noexcept
+      {
+	return __x.month() == __y.month()
+	  && __x.weekday_indexed() == __y.weekday_indexed();
+      }
+
+      friend constexpr month_weekday
+      operator/(const chrono::month& __m,
+		const chrono::weekday_indexed& __wdi) noexcept
+      { return {__m, __wdi}; }
+
+      friend constexpr month_weekday
+      operator/(int __m, const chrono::weekday_indexed& __wdi) noexcept
+      { return chrono::month(unsigned(__m)) / __wdi; }
+
+      friend constexpr month_weekday
+      operator/(const chrono::weekday_indexed& __wdi,
+		const chrono::month& __m) noexcept
+      { return __m / __wdi; }
+
+      friend constexpr month_weekday
+      operator/(const chrono::weekday_indexed& __wdi, int __m) noexcept
+      { return __m / __wdi; }
+
+      friend constexpr year_month_weekday
+      operator/(int __y, const month_weekday& __mwd) noexcept;
+
+      friend constexpr year_month_weekday
+      operator/(const month_weekday& __mwd, int __y) noexcept;
+
+      // TODO: Implement operator<<.
+    };
+
+    // MONTH_WEEKDAY_LAST
+
+    class month_weekday_last
+    {
+    private:
+      chrono::month _M_m;
+      chrono::weekday_last _M_wdl;
+
+    public:
+      constexpr
+      month_weekday_last(const chrono::month& __m,
+			 const chrono::weekday_last& __wdl) noexcept
+      :_M_m{__m}, _M_wdl{__wdl}
+      { }
+
+      constexpr chrono::month
+      month() const noexcept
+      { return _M_m; }
+
+      constexpr chrono::weekday_last
+      weekday_last() const noexcept
+      { return _M_wdl; }
+
+      constexpr bool
+      ok() const noexcept
+      { return _M_m.ok() && _M_wdl.ok(); }
+
+      friend constexpr bool
+      operator==(const month_weekday_last& __x,
+		 const month_weekday_last& __y) noexcept
+      {
+	return __x.month() == __y.month()
+	  && __x.weekday_last() == __y.weekday_last();
+      }
+
+      friend constexpr month_weekday_last
+      operator/(const chrono::month& __m,
+		const chrono::weekday_last& __wdl) noexcept
+      { return {__m, __wdl}; }
+
+      friend constexpr month_weekday_last
+      operator/(int __m, const chrono::weekday_last& __wdl) noexcept
+      { return chrono::month(unsigned(__m)) / __wdl; }
+
+      friend constexpr month_weekday_last
+      operator/(const chrono::weekday_last& __wdl,
+		const chrono::month& __m) noexcept
+      { return __m / __wdl; }
+
+      friend constexpr month_weekday_last
+      operator/(const chrono::weekday_last& __wdl, int __m) noexcept
+      { return chrono::month(unsigned(__m)) / __wdl; }
+
+      friend constexpr year_month_weekday_last
+      operator/(int __y, const month_weekday_last& __mwdl) noexcept;
+
+      friend constexpr year_month_weekday_last
+      operator/(const month_weekday_last& __mwdl, int __y) noexcept;
+
+      // TODO: Implement operator<<.
+    };
+
+    // YEAR_MONTH
+
+    namespace __detail
+    {
+      // [time.cal.ym], [time.cal.ymd], etc constrain the 'months'-based
+      // addition/subtraction operator overloads like so:
+      //
+      //   Constraints: if the argument supplied by the caller for the months
+      //   parameter is convertible to years, its implicit conversion sequence
+      //   to years is worse than its implicit conversion sequence to months.
+      //
+      // We realize this constraint by templatizing the 'months'-based
+      // overloads (using a dummy defaulted template parameter), so that
+      // overload resolution doesn't select the 'months'-based overload unless
+      // the implicit conversion sequence to 'months' is better than that to
+      // 'years'.
+      using __months_years_conversion_disambiguator = void;
+    }
+
+    class year_month
+    {
+    private:
+      chrono::year _M_y;
+      chrono::month _M_m;
+
+    public:
+      year_month() = default;
+
+      constexpr
+      year_month(const chrono::year& __y, const chrono::month& __m) noexcept
+      : _M_y{__y}, _M_m{__m}
+      { }
+
+      constexpr chrono::year
+      year() const noexcept
+      { return _M_y; }
+
+      constexpr chrono::month
+      month() const noexcept
+      { return _M_m; }
+
+      template<typename = __detail::__months_years_conversion_disambiguator>
+	constexpr year_month&
+	operator+=(const months& __dm) noexcept
+	{
+	  *this = *this + __dm;
+	  return *this;
+	}
+
+      template<typename = __detail::__months_years_conversion_disambiguator>
+	constexpr year_month&
+	operator-=(const months& __dm) noexcept
+	{
+	  *this = *this - __dm;
+	  return *this;
+	}
+
+      constexpr year_month&
+      operator+=(const years& __dy)  noexcept
+      {
+	*this = *this + __dy;
+	return *this;
+      }
+
+      constexpr year_month&
+      operator-=(const years& __dy)  noexcept
+      {
+	*this = *this - __dy;
+	return *this;
+      }
+
+      constexpr bool
+      ok() const noexcept
+      { return _M_y.ok() && _M_m.ok(); }
+
+      friend constexpr bool
+      operator==(const year_month& __x, const year_month& __y) noexcept
+      { return __x.year() == __y.year() && __x.month() == __y.month(); }
+
+      friend constexpr strong_ordering
+      operator<=>(const year_month& __x, const year_month& __y) noexcept
+	= default;
+
+      template<typename = __detail::__months_years_conversion_disambiguator>
+	friend constexpr year_month
+	operator+(const year_month& __ym, const months& __dm) noexcept
+	{
+	  // TODO: Optimize?
+	  auto __m = __ym.month() + __dm;
+	  auto __i = int(unsigned(__ym.month())) - 1 + __dm.count();
+	  auto __y = (__i < 0
+		      ? __ym.year() + years{(__i - 11) / 12}
+		      : __ym.year() + years{__i / 12});
+	  return __y / __m;
+	}
+
+      template<typename = __detail::__months_years_conversion_disambiguator>
+	friend constexpr year_month
+	operator+(const months& __dm, const year_month& __ym) noexcept
+	{ return __ym + __dm; }
+
+      template<typename = __detail::__months_years_conversion_disambiguator>
+	friend constexpr year_month
+	operator-(const year_month& __ym, const months& __dm) noexcept
+	{ return __ym + -__dm; }
+
+      friend constexpr months
+      operator-(const year_month& __x, const year_month& __y) noexcept
+      {
+	return (__x.year() - __y.year()
+		+ months{static_cast<int>(unsigned{__x.month()})
+			 - static_cast<int>(unsigned{__y.month()})});
+      }
+
+      friend constexpr year_month
+      operator+(const year_month& __ym, const years& __dy) noexcept
+      { return (__ym.year() + __dy) / __ym.month(); }
+
+      friend constexpr year_month
+      operator+(const years& __dy, const year_month& __ym) noexcept
+      { return __ym + __dy; }
+
+      friend constexpr year_month
+      operator-(const year_month& __ym, const years& __dy) noexcept
+      { return __ym + -__dy; }
+
+      friend constexpr year_month
+      operator/(const chrono::year& __y, const chrono::month& __m) noexcept
+      { return {__y, __m}; }
+
+      friend constexpr year_month
+      operator/(const chrono::year& __y, int __m) noexcept
+      { return {__y, chrono::month(unsigned(__m))}; }
+
+      friend constexpr year_month_day
+      operator/(const year_month& __ym, int __d) noexcept;
+
+      friend constexpr year_month_day_last
+      operator/(const year_month& __ym, last_spec) noexcept;
+
+      // TODO: Implement operator<<, from_stream.
+    };
+
+    // YEAR_MONTH_DAY
+
+    class year_month_day
+    {
+    private:
+      chrono::year _M_y;
+      chrono::month _M_m;
+      chrono::day _M_d;
+
+      static constexpr year_month_day _S_from_days(const days& __dp) noexcept;
+
+      constexpr days _M_days_since_epoch() const noexcept;
+
+    public:
+      year_month_day() = default;
+
+      constexpr
+      year_month_day(const chrono::year& __y, const chrono::month& __m,
+		     const chrono::day& __d) noexcept
+      : _M_y{__y}, _M_m{__m}, _M_d{__d}
+      { }
+
+      constexpr
+      year_month_day(const year_month_day_last& __ymdl) noexcept;
+
+      constexpr
+      year_month_day(const sys_days& __dp) noexcept
+      : year_month_day(_S_from_days(__dp.time_since_epoch()))
+      { }
+
+      explicit constexpr
+      year_month_day(const local_days& __dp) noexcept
+      : year_month_day(sys_days{__dp.time_since_epoch()})
+      { }
+
+      template<typename = __detail::__months_years_conversion_disambiguator>
+	constexpr year_month_day&
+	operator+=(const months& __m) noexcept
+	{
+	  *this = *this + __m;
+	  return *this;
+	}
+
+      template<typename = __detail::__months_years_conversion_disambiguator>
+	constexpr year_month_day&
+	operator-=(const months& __m) noexcept
+	{
+	  *this = *this - __m;
+	  return *this;
+	}
+
+      constexpr year_month_day&
+      operator+=(const years& __y) noexcept
+      {
+	*this = *this + __y;
+	return *this;
+      }
+
+      constexpr year_month_day&
+      operator-=(const years& __y) noexcept
+      {
+	*this = *this - __y;
+	return *this;
+      }
+
+      constexpr chrono::year
+      year() const noexcept
+      { return _M_y; }
+
+      constexpr chrono::month
+      month() const noexcept
+      { return _M_m; }
+
+      constexpr chrono::day
+      day() const noexcept
+      { return _M_d; }
+
+      constexpr
+      operator sys_days() const noexcept
+      { return sys_days{_M_days_since_epoch()}; }
+
+      explicit constexpr
+      operator local_days() const noexcept
+      { return local_days{sys_days{*this}.time_since_epoch()}; }
+
+      constexpr bool ok() const noexcept;
+
+      friend constexpr bool
+      operator==(const year_month_day& __x, const year_month_day& __y) noexcept
+      {
+	return __x.year() == __y.year()
+	  && __x.month() == __y.month()
+	  && __x.day() == __y.day();
+      }
+
+      friend constexpr strong_ordering
+      operator<=>(const year_month_day& __x, const year_month_day& __y) noexcept
+	= default;
+
+      template<typename = __detail::__months_years_conversion_disambiguator>
+	friend constexpr year_month_day
+	operator+(const year_month_day& __ymd, const months& __dm) noexcept
+	{ return (__ymd.year() / __ymd.month() + __dm) / __ymd.day(); }
+
+      template<typename = __detail::__months_years_conversion_disambiguator>
+	friend constexpr year_month_day
+	operator+(const months& __dm, const year_month_day& __ymd) noexcept
+	{ return __ymd + __dm; }
+
+      friend constexpr year_month_day
+      operator+(const year_month_day& __ymd, const years& __dy) noexcept
+      { return (__ymd.year() + __dy) / __ymd.month() / __ymd.day(); }
+
+      friend constexpr year_month_day
+      operator+(const years& __dy, const year_month_day& __ymd) noexcept
+      { return __ymd + __dy; }
+
+      template<typename = __detail::__months_years_conversion_disambiguator>
+	friend constexpr year_month_day
+	operator-(const year_month_day& __ymd, const months& __dm) noexcept
+	{ return __ymd + -__dm; }
+
+      friend constexpr year_month_day
+      operator-(const year_month_day& __ymd, const years& __dy) noexcept
+      { return __ymd + -__dy; }
+
+      friend constexpr year_month_day
+      operator/(const year_month& __ym, const chrono::day& __d) noexcept
+      { return {__ym.year(), __ym.month(), __d}; }
+
+      friend constexpr year_month_day
+      operator/(const year_month& __ym, int __d) noexcept
+      { return __ym / chrono::day{unsigned(__d)}; }
+
+      friend constexpr year_month_day
+      operator/(const chrono::year& __y, const month_day& __md) noexcept
+      { return __y / __md.month() / __md.day(); }
+
+      friend constexpr year_month_day
+      operator/(int __y, const month_day& __md) noexcept
+      { return chrono::year{__y} / __md; }
+
+      friend constexpr year_month_day
+      operator/(const month_day& __md, const chrono::year& __y) noexcept
+      { return __y / __md; }
+
+      friend constexpr year_month_day
+      operator/(const month_day& __md, int __y) noexcept
+      { return chrono::year(__y) / __md; }
+
+      // TODO: Implement operator<<, from_stream.
+    };
+
+    // Construct from days since 1970/01/01.
+    // Proposition 6.3 of Neri and Schneider,
+    // "Euclidean Affine Functions and Applications to Calendar Algorithms".
+    // https://arxiv.org/abs/2102.06959
+    constexpr year_month_day
+    year_month_day::_S_from_days(const days& __dp) noexcept
+    {
+      constexpr auto __z2    = static_cast<uint32_t>(-1468000);
+      constexpr auto __r2_e3 = static_cast<uint32_t>(536895458);
+
+      const auto __r0 = static_cast<uint32_t>(__dp.count()) + __r2_e3;
+
+      const auto __n1 = 4 * __r0 + 3;
+      const auto __q1 = __n1 / 146097;
+      const auto __r1 = __n1 % 146097 / 4;
+
+      constexpr auto __p32 = static_cast<uint64_t>(1) << 32;
+      const auto __n2 = 4 * __r1 + 3;
+      const auto __u2 = static_cast<uint64_t>(2939745) * __n2;
+      const auto __q2 = static_cast<uint32_t>(__u2 / __p32);
+      const auto __r2 = static_cast<uint32_t>(__u2 % __p32) / 2939745 / 4;
+
+      constexpr auto __p16 = static_cast<uint32_t>(1) << 16;
+      const auto __n3 = 2141 * __r2 + 197913;
+      const auto __q3 = __n3 / __p16;
+      const auto __r3 = __n3 % __p16 / 2141;
+
+      const auto __y0 = 100 * __q1 + __q2;
+      const auto __m0 = __q3;
+      const auto __d0 = __r3;
+
+      const auto __j  = __r2 >= 306;
+      const auto __y1 = __y0 + __j;
+      const auto __m1 = __j ? __m0 - 12 : __m0;
+      const auto __d1 = __d0 + 1;
+
+      return year_month_day{chrono::year{static_cast<int>(__y1 + __z2)},
+			    chrono::month{__m1}, chrono::day{__d1}};
+    }
+
+    // Days since 1970/01/01.
+    // Proposition 6.2 of Neri and Schneider,
+    // "Euclidean Affine Functions and Applications to Calendar Algorithms".
+    // https://arxiv.org/abs/2102.06959
+    constexpr days
+    year_month_day::_M_days_since_epoch() const noexcept
+    {
+      auto constexpr __z2    = static_cast<uint32_t>(-1468000);
+      auto constexpr __r2_e3 = static_cast<uint32_t>(536895458);
+
+      const auto __y1 = static_cast<uint32_t>(static_cast<int>(_M_y)) - __z2;
+      const auto __m1 = static_cast<uint32_t>(static_cast<unsigned>(_M_m));
+      const auto __d1 = static_cast<uint32_t>(static_cast<unsigned>(_M_d));
+
+      const auto __j  = static_cast<uint32_t>(__m1 < 3);
+      const auto __y0 = __y1 - __j;
+      const auto __m0 = __j ? __m1 + 12 : __m1;
+      const auto __d0 = __d1 - 1;
+
+      const auto __q1 = __y0 / 100;
+      const auto __yc = 1461 * __y0 / 4 - __q1 + __q1 / 4;
+      const auto __mc = (979 *__m0 - 2919) / 32;
+      const auto __dc = __d0;
+
+      return days{static_cast<int32_t>(__yc + __mc + __dc - __r2_e3)};
+    }
+
+    // YEAR_MONTH_DAY_LAST
+
+    class year_month_day_last
+    {
+    private:
+      chrono::year _M_y;
+      chrono::month_day_last _M_mdl;
+
+    public:
+      constexpr
+      year_month_day_last(const chrono::year& __y,
+			  const chrono::month_day_last& __mdl) noexcept
+      : _M_y{__y}, _M_mdl{__mdl}
+      { }
+
+      template<typename = __detail::__months_years_conversion_disambiguator>
+	constexpr year_month_day_last&
+	operator+=(const months& __m) noexcept
+	{
+	  *this = *this + __m;
+	  return *this;
+	}
+
+      template<typename = __detail::__months_years_conversion_disambiguator>
+	constexpr year_month_day_last&
+	operator-=(const months& __m) noexcept
+	{
+	  *this = *this - __m;
+	  return *this;
+	}
+
+      constexpr year_month_day_last&
+      operator+=(const years& __y)  noexcept
+      {
+	*this = *this + __y;
+	return *this;
+      }
+
+      constexpr year_month_day_last&
+      operator-=(const years& __y)  noexcept
+      {
+	*this = *this - __y;
+	return *this;
+      }
+
+      constexpr chrono::year
+      year() const noexcept
+      { return _M_y; }
+
+      constexpr chrono::month
+      month() const noexcept
+      { return _M_mdl.month(); }
+
+      constexpr chrono::month_day_last
+      month_day_last() const noexcept
+      { return _M_mdl; }
+
+      // Return A day representing the last day of this year, month pair.
+      constexpr chrono::day
+      day() const noexcept
+      {
+	const auto __m = static_cast<unsigned>(month());
+
+	// Excluding February, the last day of month __m is either 30 or 31 or,
+	// in another words, it is 30 + b = 30 | b, where b is in {0, 1}.
+
+	// If __m in {1, 3, 4, 5, 6, 7}, then b is 1 if, and only if __m is odd.
+	// Hence, b = __m & 1 = (__m ^ 0) & 1.
+
+	// If __m in {8, 9, 10, 11, 12}, then b is 1 if, and only if __m is even.
+	// Hence, b = (__m ^ 1) & 1.
+
+	// Therefore, b = (__m ^ c) & 1, where c = 0, if __m < 8, or c = 1 if
+	// __m >= 8, that is, c = __m >> 3.
+
+	// The above mathematically justifies this implementation whose
+	// performance does not depend on look-up tables being on the L1 cache.
+	return chrono::day{__m != 2 ? ((__m ^ (__m >> 3)) & 1) | 30
+				    : _M_y.is_leap() ? 29 : 28};
+      }
+
+      constexpr
+      operator sys_days() const noexcept
+      { return sys_days{year() / month() / day()}; }
+
+      explicit constexpr
+      operator local_days() const noexcept
+      { return local_days{sys_days{*this}.time_since_epoch()}; }
+
+      constexpr bool
+      ok() const noexcept
+      { return _M_y.ok() && _M_mdl.ok(); }
+
+      friend constexpr bool
+      operator==(const year_month_day_last& __x,
+		 const year_month_day_last& __y) noexcept
+      {
+	return __x.year() == __y.year()
+	  && __x.month_day_last() == __y.month_day_last();
+      }
+
+      friend constexpr strong_ordering
+      operator<=>(const year_month_day_last& __x,
+		  const year_month_day_last& __y) noexcept
+	= default;
+
+      template<typename = __detail::__months_years_conversion_disambiguator>
+	friend constexpr year_month_day_last
+	operator+(const year_month_day_last& __ymdl,
+		  const months& __dm) noexcept
+	{ return (__ymdl.year() / __ymdl.month() + __dm) / last; }
+
+      template<typename = __detail::__months_years_conversion_disambiguator>
+	friend constexpr year_month_day_last
+	operator+(const months& __dm,
+		  const year_month_day_last& __ymdl) noexcept
+	{ return __ymdl + __dm; }
+
+      template<typename = __detail::__months_years_conversion_disambiguator>
+	friend constexpr year_month_day_last
+	operator-(const year_month_day_last& __ymdl,
+		  const months& __dm) noexcept
+	{ return __ymdl + -__dm; }
+
+      friend constexpr year_month_day_last
+      operator+(const year_month_day_last& __ymdl,
+		const years& __dy) noexcept
+      { return {__ymdl.year() + __dy, __ymdl.month_day_last()}; }
+
+      friend constexpr year_month_day_last
+      operator+(const years& __dy,
+		const year_month_day_last& __ymdl) noexcept
+      { return __ymdl + __dy; }
+
+      friend constexpr year_month_day_last
+      operator-(const year_month_day_last& __ymdl,
+		const years& __dy) noexcept
+      { return __ymdl + -__dy; }
+
+      friend constexpr year_month_day_last
+      operator/(const year_month& __ym, last_spec) noexcept
+      { return {__ym.year(), chrono::month_day_last{__ym.month()}}; }
+
+      friend constexpr year_month_day_last
+      operator/(const chrono::year& __y,
+		const chrono::month_day_last& __mdl) noexcept
+      { return {__y, __mdl}; }
+
+      friend constexpr year_month_day_last
+      operator/(int __y, const chrono::month_day_last& __mdl) noexcept
+      { return chrono::year(__y) / __mdl; }
+
+      friend constexpr year_month_day_last
+      operator/(const chrono::month_day_last& __mdl,
+		const chrono::year& __y) noexcept
+      { return __y / __mdl; }
+
+      friend constexpr year_month_day_last
+      operator/(const chrono::month_day_last& __mdl, int __y) noexcept
+      { return chrono::year(__y) / __mdl; }
+
+      // TODO: Implement operator<<.
+    };
+
+    // year_month_day ctor from year_month_day_last
+    constexpr
+    year_month_day::year_month_day(const year_month_day_last& __ymdl) noexcept
+    : _M_y{__ymdl.year()}, _M_m{__ymdl.month()}, _M_d{__ymdl.day()}
+    { }
+
+    constexpr bool
+    year_month_day::ok() const noexcept
+    {
+      if (!_M_y.ok() || !_M_m.ok())
+	return false;
+      return chrono::day{1} <= _M_d && _M_d <= (_M_y / _M_m / last).day();
+    }
+
+    // YEAR_MONTH_WEEKDAY
+
+    class year_month_weekday
+    {
+    private:
+      chrono::year _M_y;
+      chrono::month _M_m;
+      chrono::weekday_indexed _M_wdi;
+
+      static constexpr year_month_weekday
+      _S_from_sys_days(const sys_days& __dp)
+      {
+	year_month_day __ymd{__dp};
+	chrono::weekday __wd{__dp};
+	auto __index = __wd[(unsigned{__ymd.day()} - 1) / 7 + 1];
+	return {__ymd.year(), __ymd.month(), __index};
+      }
+
+    public:
+      year_month_weekday() = default;
+
+      constexpr
+      year_month_weekday(const chrono::year& __y, const chrono::month& __m,
+			 const chrono::weekday_indexed& __wdi) noexcept
+      : _M_y{__y}, _M_m{__m}, _M_wdi{__wdi}
+      { }
+
+      constexpr
+      year_month_weekday(const sys_days& __dp) noexcept
+      : year_month_weekday{_S_from_sys_days(__dp)}
+      { }
+
+      explicit constexpr
+      year_month_weekday(const local_days& __dp) noexcept
+      : year_month_weekday{sys_days{__dp.time_since_epoch()}}
+      { }
+
+      template<typename = __detail::__months_years_conversion_disambiguator>
+	constexpr year_month_weekday&
+	operator+=(const months& __m) noexcept
+	{
+	  *this = *this + __m;
+	  return *this;
+	}
+
+      template<typename = __detail::__months_years_conversion_disambiguator>
+	constexpr year_month_weekday&
+	operator-=(const months& __m) noexcept
+	{
+	  *this = *this - __m;
+	  return *this;
+	}
+
+      constexpr year_month_weekday&
+      operator+=(const years& __y) noexcept
+      {
+	*this = *this + __y;
+	return *this;
+      }
+
+      constexpr year_month_weekday&
+      operator-=(const years& __y) noexcept
+      {
+	*this = *this - __y;
+	return *this;
+      }
+
+      constexpr chrono::year
+      year() const noexcept
+      { return _M_y; }
+
+      constexpr chrono::month
+      month() const noexcept
+      { return _M_m; }
+
+      constexpr chrono::weekday
+      weekday() const noexcept
+      { return _M_wdi.weekday(); }
+
+      constexpr unsigned
+      index() const noexcept
+      { return _M_wdi.index(); }
+
+      constexpr chrono::weekday_indexed
+      weekday_indexed() const noexcept
+      { return _M_wdi; }
+
+      constexpr
+      operator sys_days() const noexcept
+      {
+	auto __d = sys_days{year() / month() / 1};
+	return __d + (weekday() - chrono::weekday(__d)
+		      + days{(static_cast<int>(index())-1)*7});
+      }
+
+      explicit constexpr
+      operator local_days() const noexcept
+      { return local_days{sys_days{*this}.time_since_epoch()}; }
+
+      constexpr bool
+      ok() const noexcept
+      {
+	if (!_M_y.ok() || !_M_m.ok() || !_M_wdi.ok())
+	  return false;
+	if (_M_wdi.index() <= 4)
+	  return true;
+	days __d = (_M_wdi.weekday()
+		    - chrono::weekday{sys_days{_M_y / _M_m / 1}}
+		    + days((_M_wdi.index()-1)*7 + 1));
+	__glibcxx_assert(__d.count() >= 1);
+	return __d.count() <= unsigned{(_M_y / _M_m / last).day()};
+      }
+
+      friend constexpr bool
+      operator==(const year_month_weekday& __x,
+		 const year_month_weekday& __y) noexcept
+      {
+	return __x.year() == __y.year()
+	  && __x.month() == __y.month()
+	  && __x.weekday_indexed() == __y.weekday_indexed();
+      }
+
+      template<typename = __detail::__months_years_conversion_disambiguator>
+	friend constexpr year_month_weekday
+	operator+(const year_month_weekday& __ymwd, const months& __dm) noexcept
+	{
+	  return ((__ymwd.year() / __ymwd.month() + __dm)
+		  / __ymwd.weekday_indexed());
+	}
+
+      template<typename = __detail::__months_years_conversion_disambiguator>
+	friend constexpr year_month_weekday
+	operator+(const months& __dm, const year_month_weekday& __ymwd) noexcept
+	{ return __ymwd + __dm; }
+
+      friend constexpr year_month_weekday
+      operator+(const year_month_weekday& __ymwd, const years& __dy) noexcept
+      { return {__ymwd.year() + __dy, __ymwd.month(), __ymwd.weekday_indexed()}; }
+
+      friend constexpr year_month_weekday
+      operator+(const years& __dy, const year_month_weekday& __ymwd) noexcept
+      { return __ymwd + __dy; }
+
+      template<typename = __detail::__months_years_conversion_disambiguator>
+	friend constexpr year_month_weekday
+	operator-(const year_month_weekday& __ymwd, const months& __dm) noexcept
+	{ return __ymwd + -__dm; }
+
+      friend constexpr year_month_weekday
+      operator-(const year_month_weekday& __ymwd, const years& __dy) noexcept
+      { return __ymwd + -__dy; }
+
+      friend constexpr year_month_weekday
+      operator/(const year_month& __ym,
+		const chrono::weekday_indexed& __wdi) noexcept
+      { return {__ym.year(), __ym.month(), __wdi}; }
+
+      friend constexpr year_month_weekday
+      operator/(const chrono::year& __y, const month_weekday& __mwd) noexcept
+      { return {__y, __mwd.month(), __mwd.weekday_indexed()}; }
+
+      friend constexpr year_month_weekday
+      operator/(int __y, const month_weekday& __mwd) noexcept
+      { return chrono::year(__y) / __mwd; }
+
+      friend constexpr year_month_weekday
+      operator/(const month_weekday& __mwd, const chrono::year& __y) noexcept
+      { return __y / __mwd; }
+
+      friend constexpr year_month_weekday
+      operator/(const month_weekday& __mwd, int __y) noexcept
+      { return chrono::year(__y) / __mwd; }
+
+      // TODO: Implement operator<<.
+    };
+
+    // YEAR_MONTH_WEEKDAY_LAST
+
+    class year_month_weekday_last
+    {
+    private:
+      chrono::year _M_y;
+      chrono::month _M_m;
+      chrono::weekday_last _M_wdl;
+
+    public:
+      constexpr
+      year_month_weekday_last(const chrono::year& __y, const chrono::month& __m,
+			      const chrono::weekday_last& __wdl) noexcept
+      : _M_y{__y}, _M_m{__m}, _M_wdl{__wdl}
+      { }
+
+      template<typename = __detail::__months_years_conversion_disambiguator>
+	constexpr year_month_weekday_last&
+	operator+=(const months& __m) noexcept
+	{
+	  *this = *this + __m;
+	  return *this;
+	}
+
+      template<typename = __detail::__months_years_conversion_disambiguator>
+	constexpr year_month_weekday_last&
+	operator-=(const months& __m) noexcept
+	{
+	  *this = *this - __m;
+	  return *this;
+	}
+
+      constexpr year_month_weekday_last&
+      operator+=(const years& __y)  noexcept
+      {
+	*this = *this + __y;
+	return *this;
+      }
+
+      constexpr year_month_weekday_last&
+      operator-=(const years& __y)  noexcept
+      {
+	*this = *this - __y;
+	return *this;
+      }
+
+      constexpr chrono::year
+      year() const noexcept
+      { return _M_y; }
+
+      constexpr chrono::month
+      month() const noexcept
+      { return _M_m; }
+
+      constexpr chrono::weekday
+      weekday() const noexcept
+      { return _M_wdl.weekday(); }
+
+      constexpr chrono::weekday_last
+      weekday_last() const noexcept
+      { return _M_wdl; }
+
+      constexpr
+      operator sys_days() const noexcept
+      {
+	const auto __d = sys_days{_M_y / _M_m / last};
+	return sys_days{(__d - (chrono::weekday{__d}
+				- _M_wdl.weekday())).time_since_epoch()};
+      }
+
+      explicit constexpr
+      operator local_days() const noexcept
+      { return local_days{sys_days{*this}.time_since_epoch()}; }
+
+      constexpr bool
+      ok() const noexcept
+      { return _M_y.ok() && _M_m.ok() && _M_wdl.ok(); }
+
+      friend constexpr bool
+      operator==(const year_month_weekday_last& __x,
+		 const year_month_weekday_last& __y) noexcept
+      {
+	return __x.year() == __y.year()
+	  && __x.month() == __y.month()
+	  && __x.weekday_last() == __y.weekday_last();
+      }
+
+      template<typename = __detail::__months_years_conversion_disambiguator>
+	friend constexpr year_month_weekday_last
+	operator+(const year_month_weekday_last& __ymwdl,
+		  const months& __dm) noexcept
+	{
+	  return ((__ymwdl.year() / __ymwdl.month() + __dm)
+		  / __ymwdl.weekday_last());
+	}
+
+      template<typename = __detail::__months_years_conversion_disambiguator>
+	friend constexpr year_month_weekday_last
+	operator+(const months& __dm,
+		  const year_month_weekday_last& __ymwdl) noexcept
+	{ return __ymwdl + __dm; }
+
+      friend constexpr year_month_weekday_last
+      operator+(const year_month_weekday_last& __ymwdl,
+		const years& __dy) noexcept
+      { return {__ymwdl.year() + __dy, __ymwdl.month(), __ymwdl.weekday_last()}; }
+
+      friend constexpr year_month_weekday_last
+      operator+(const years& __dy,
+		const year_month_weekday_last& __ymwdl) noexcept
+      { return __ymwdl + __dy; }
+
+      template<typename = __detail::__months_years_conversion_disambiguator>
+	friend constexpr year_month_weekday_last
+	operator-(const year_month_weekday_last& __ymwdl,
+		  const months& __dm) noexcept
+	{ return __ymwdl + -__dm; }
+
+      friend constexpr year_month_weekday_last
+      operator-(const year_month_weekday_last& __ymwdl,
+		const years& __dy) noexcept
+      { return __ymwdl + -__dy; }
+
+      friend constexpr year_month_weekday_last
+      operator/(const year_month& __ym,
+		const chrono::weekday_last& __wdl) noexcept
+      { return {__ym.year(), __ym.month(), __wdl}; }
+
+      friend constexpr year_month_weekday_last
+      operator/(const chrono::year& __y,
+		const chrono::month_weekday_last& __mwdl) noexcept
+      { return {__y, __mwdl.month(), __mwdl.weekday_last()}; }
+
+      friend constexpr year_month_weekday_last
+      operator/(int __y, const chrono::month_weekday_last& __mwdl) noexcept
+      { return chrono::year(__y) / __mwdl; }
+
+      friend constexpr year_month_weekday_last
+      operator/(const chrono::month_weekday_last& __mwdl,
+		const chrono::year& __y) noexcept
+      { return __y / __mwdl; }
+
+      friend constexpr year_month_weekday_last
+      operator/(const chrono::month_weekday_last& __mwdl, int __y) noexcept
+      { return chrono::year(__y) / __mwdl; }
+
+      // TODO: Implement operator<<.
+    };
+
+    // HH_MM_SS
+
+    namespace __detail
+    {
+      consteval long long
+      __pow10(unsigned __n)
+      {
+	long long __r = 1;
+	while (__n-- > 0)
+	  __r *= 10;
+	return __r;
+      }
+    }
+
+    template<typename _Duration>
+      class hh_mm_ss
+      {
+      private:
+	static constexpr int
+	_S_fractional_width()
+	{
+	  int __multiplicity_2 = 0;
+	  int __multiplicity_5 = 0;
+	  auto __den = _Duration::period::den;
+	  while ((__den % 2) == 0)
+	    {
+	      ++__multiplicity_2;
+	      __den /= 2;
+	    }
+	  while ((__den % 5) == 0)
+	    {
+	      ++__multiplicity_5;
+	      __den /= 5;
+	    }
+	  if (__den != 1)
+	    return 6;
+
+	  int __width = (__multiplicity_2 > __multiplicity_5
+			 ? __multiplicity_2 : __multiplicity_5);
+	  if (__width > 18)
+	    __width = 18;
+	  return __width;
+	}
+
+      public:
+	static constexpr unsigned fractional_width = {_S_fractional_width()};
+
+	using precision
+	  = duration<common_type_t<typename _Duration::rep,
+				   chrono::seconds::rep>,
+		     ratio<1, __detail::__pow10(fractional_width)>>;
+
+	constexpr
+	hh_mm_ss() noexcept
+	: hh_mm_ss{_Duration::zero()}
+	{ }
+
+	constexpr explicit
+	hh_mm_ss(_Duration __d) noexcept
+	: _M_is_neg (__d < _Duration::zero()),
+	  _M_h (duration_cast<chrono::hours>(abs(__d))),
+	  _M_m (duration_cast<chrono::minutes>(abs(__d) - hours())),
+	  _M_s (duration_cast<chrono::seconds>(abs(__d) - hours() - minutes()))
+	{
+	  if constexpr (treat_as_floating_point_v<typename precision::rep>)
+	    _M_ss = abs(__d) - hours() - minutes() - seconds();
+	  else
+	    _M_ss = duration_cast<precision>(abs(__d) - hours()
+					     - minutes() - seconds());
+	}
+
+	constexpr bool
+	is_negative() const noexcept
+	{ return _M_is_neg; }
+
+	constexpr chrono::hours
+	hours() const noexcept
+	{ return _M_h; }
+
+	constexpr chrono::minutes
+	minutes() const noexcept
+	{ return _M_m; }
+
+	constexpr chrono::seconds
+	seconds() const noexcept
+	{ return _M_s; }
+
+	constexpr precision
+	subseconds() const noexcept
+	{ return _M_ss; }
+
+	constexpr explicit
+	operator precision() const noexcept
+	{ return to_duration(); }
+
+	constexpr precision
+	to_duration() const noexcept
+	{
+	  if (_M_is_neg)
+	    return -(_M_h + _M_m + _M_s + _M_ss);
+	  else
+	    return _M_h + _M_m + _M_s + _M_ss;
+	}
+
+	// TODO: Implement operator<<.
+
+      private:
+	bool _M_is_neg;
+	chrono::hours _M_h;
+	chrono::minutes _M_m;
+	chrono::seconds _M_s;
+	precision _M_ss;
+      };
+
+    // 12/24 HOURS FUNCTIONS
+
+    constexpr bool
+    is_am(const hours& __h) noexcept
+    { return 0h <= __h && __h <= 11h; }
+
+    constexpr bool
+    is_pm(const hours& __h) noexcept
+    { return 12h <= __h && __h <= 23h; }
+
+    constexpr hours
+    make12(const hours& __h) noexcept
+    {
+      if (__h == 0h)
+	return 12h;
+      else if (__h > 12h)
+	return __h - 12h;
+      return __h;
+    }
+
+    constexpr hours
+    make24(const hours& __h, bool __is_pm) noexcept
+    {
+      if (!__is_pm)
+	{
+	  if (__h == 12h)
+	    return 0h;
+	  else
+	    return __h;
+	}
+      else
+	{
+	  if (__h == 12h)
+	    return __h;
+	  else
+	    return __h + 12h;
+	}
+    }
+    /// @} group chrono
+#endif // C++20
+  } // namespace chrono
+
+#if __cplusplus >= 202002L
+  inline namespace literals
+  {
+  inline namespace chrono_literals
+  {
+    /// @addtogroup chrono
+    /// @{
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wliteral-suffix"
+    /// Literal suffix for creating chrono::day objects.
+    /// @since C++20
+    constexpr chrono::day
+    operator""d(unsigned long long __d) noexcept
+    { return chrono::day{static_cast<unsigned>(__d)}; }
+
+    /// Literal suffix for creating chrono::year objects.
+    /// @since C++20
+    constexpr chrono::year
+    operator""y(unsigned long long __y) noexcept
+    { return chrono::year{static_cast<int>(__y)}; }
+#pragma GCC diagnostic pop
+    /// @}
+  } // inline namespace chrono_literals
+  } // inline namespace literals
+
+  namespace chrono
+  {
+    /// @addtogroup chrono
+    /// @{
+
+    /// @cond undocumented
+    namespace __detail
+    {
+      template<typename _Period>
+	const char*
+	__units_suffix_misc(char* __buf, size_t __n) noexcept
+	{
+	  namespace __tc = std::__detail;
+	  char* __p = __buf;
+	  __p[0] = '[';
+	  unsigned __nlen = __tc::__to_chars_len((uintmax_t)_Period::num);
+	  __tc::__to_chars_10_impl(__p + 1, __nlen, (uintmax_t)_Period::num);
+	  __p += 1 + __nlen;
+	  if constexpr (_Period::den != 1)
+	    {
+	      __p[0] = '/';
+	      unsigned __dlen = __tc::__to_chars_len((uintmax_t)_Period::den);
+	      __tc::__to_chars_10_impl(__p + 1, __dlen, (uintmax_t)_Period::den);
+	      __p += 1 + __dlen;
+	    }
+	  __p[0] = ']';
+	  __p[1] = 's';
+	  __p[2] = '\0';
+	  return __buf;
+	}
+
+      template<typename _Period, typename _CharT>
+	auto
+	__units_suffix(char* __buf, size_t __n) noexcept
+	{
+#define _GLIBCXX_UNITS_SUFFIX(period, suffix) \
+	if constexpr (is_same_v<_Period, period>)	\
+	  {						\
+	    if constexpr (is_same_v<_CharT, wchar_t>)	\
+	      return L##suffix;				\
+	    else					\
+	      return suffix;				\
+	  }						\
+	else
+
+	  _GLIBCXX_UNITS_SUFFIX(atto, "as")
+	  _GLIBCXX_UNITS_SUFFIX(femto, "fs")
+	  _GLIBCXX_UNITS_SUFFIX(pico, "ps")
+	  _GLIBCXX_UNITS_SUFFIX(nano, "ns")
+	  _GLIBCXX_UNITS_SUFFIX(micro, "\u00b5s")
+	  _GLIBCXX_UNITS_SUFFIX(milli, "ms")
+	  _GLIBCXX_UNITS_SUFFIX(centi, "cs")
+	  _GLIBCXX_UNITS_SUFFIX(deci, "ds")
+	  _GLIBCXX_UNITS_SUFFIX(ratio<1>, "s")
+	  _GLIBCXX_UNITS_SUFFIX(deca, "das")
+	  _GLIBCXX_UNITS_SUFFIX(hecto, "hs")
+	  _GLIBCXX_UNITS_SUFFIX(kilo, "ks")
+	  _GLIBCXX_UNITS_SUFFIX(mega, "Ms")
+	  _GLIBCXX_UNITS_SUFFIX(giga, "Gs")
+	  _GLIBCXX_UNITS_SUFFIX(tera, "Ts")
+	  _GLIBCXX_UNITS_SUFFIX(tera, "Ts")
+	  _GLIBCXX_UNITS_SUFFIX(peta, "Ps")
+	  _GLIBCXX_UNITS_SUFFIX(exa, "Es")
+	  _GLIBCXX_UNITS_SUFFIX(ratio<60>, "min")
+	  _GLIBCXX_UNITS_SUFFIX(ratio<3600>, "h")
+	  _GLIBCXX_UNITS_SUFFIX(ratio<86400>, "d")
+#undef _GLIBCXX_UNITS_SUFFIX
+	  return __detail::__units_suffix_misc<_Period>(__buf, __n);
+	}
+    } // namespace __detail
+    /// @endcond
+
+    template<typename _CharT, typename _Traits,
+	     typename _Rep, typename _Period>
+      inline basic_ostream<_CharT, _Traits>&
+      operator<<(std::basic_ostream<_CharT, _Traits>& __os,
+		const duration<_Rep, _Period>& __d)
+      {
+	using period = typename _Period::type;
+	char __buf[sizeof("[/]s") + 2 * numeric_limits<intmax_t>::digits10];
+	std::basic_ostringstream<_CharT, _Traits> __s;
+	__s.flags(__os.flags());
+	__s.imbue(__os.getloc());
+	__s.precision(__os.precision());
+	__s << __d.count();
+	__s << __detail::__units_suffix<period, _CharT>(__buf, sizeof(__buf));
+	__os << std::move(__s).str();
+	return __os;
+      }
+
+    // TODO: from_stream for duration
+
+    /// @} group chrono
+  } // namespace chrono
+#endif // C++20
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif // C++11
+
+#endif //_GLIBCXX_CHRONO
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--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@cinttypes
@@ -0,0 +1,81 @@
+// <cinttypes> -*- C++ -*-
+
+// Copyright (C) 2007-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file include/cinttypes
+ *  This is a Standard C++ Library header.
+ */
+
+#ifndef _GLIBCXX_CINTTYPES
+#define _GLIBCXX_CINTTYPES 1
+
+#pragma GCC system_header
+
+#if __cplusplus < 201103L
+# include <bits/c++0x_warning.h>
+#else
+
+#include <cstdint>
+
+// For 27.9.2/3 (see C99, Note 184)
+#if _GLIBCXX_HAVE_INTTYPES_H
+# ifndef __STDC_FORMAT_MACROS
+#  define _UNDEF__STDC_FORMAT_MACROS
+#  define __STDC_FORMAT_MACROS
+# endif
+# include <inttypes.h>
+# ifdef _UNDEF__STDC_FORMAT_MACROS
+#  undef __STDC_FORMAT_MACROS
+#  undef _UNDEF__STDC_FORMAT_MACROS
+# endif
+#endif
+
+#ifdef _GLIBCXX_USE_C99_INTTYPES_TR1
+
+namespace std
+{
+  // types
+  using ::imaxdiv_t;
+
+  // functions
+  using ::imaxabs;
+  using ::imaxdiv;
+
+  // GCC does not support extended integer types
+  // intmax_t abs(intmax_t)
+  // imaxdiv_t div(intmax_t, intmax_t)
+
+  using ::strtoimax;
+  using ::strtoumax;
+
+#if defined(_GLIBCXX_USE_WCHAR_T) && _GLIBCXX_USE_C99_INTTYPES_WCHAR_T_TR1
+  using ::wcstoimax;
+  using ::wcstoumax;
+#endif
+} // namespace std
+
+#endif // _GLIBCXX_USE_C99_INTTYPES_TR1
+
+#endif // C++11
+
+#endif // _GLIBCXX_CINTTYPES
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index 0000000000000000000000000000000000000000..04db985efc78010c71e6a97e396aee664e978ed7
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@ciso646
@@ -0,0 +1,38 @@
+// -*- C++ -*- forwarding header.
+
+// Copyright (C) 2001-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file ciso646
+ *  This is a Standard C++ Library file.  You should @c \#include this file
+ *  in your programs, rather than any of the @a *.h implementation files.
+ *
+ *  This is the C++ version of the Standard C Library header @c iso646.h,
+ *  which is empty in C++.
+ */
+#ifndef _GLIBCXX_CISO646
+#define _GLIBCXX_CISO646
+
+#pragma GCC system_header
+
+#include <bits/c++config.h>
+#endif
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@climits b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@climits
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--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@climits
@@ -0,0 +1,59 @@
+// -*- C++ -*- forwarding header.
+
+// Copyright (C) 1997-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file include/climits
+ *  This is a Standard C++ Library file.  You should @c \#include this file
+ *  in your programs, rather than any of the @a *.h implementation files.
+ *
+ *  This is the C++ version of the Standard C Library header @c limits.h,
+ *  and its contents are (mostly) the same as that header, but are all
+ *  contained in the namespace @c std (except for names which are defined
+ *  as macros in C).
+ */
+
+//
+// ISO C++ 14882: 18.2.2  Implementation properties: C library
+//
+
+#pragma GCC system_header
+
+#include <bits/c++config.h>
+#include <limits.h>
+
+#ifndef _GLIBCXX_CLIMITS
+#define _GLIBCXX_CLIMITS 1
+
+#ifndef LLONG_MIN
+#define LLONG_MIN (-__LONG_LONG_MAX__ - 1)
+#endif
+
+#ifndef LLONG_MAX
+#define LLONG_MAX __LONG_LONG_MAX__
+#endif
+
+#ifndef ULLONG_MAX
+#define ULLONG_MAX (__LONG_LONG_MAX__ * 2ULL + 1)
+#endif
+
+#endif
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@clocale b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@clocale
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--- /dev/null
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@@ -0,0 +1,58 @@
+// -*- C++ -*- forwarding header.
+
+// Copyright (C) 1997-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file clocale
+ *  This is a Standard C++ Library file.  You should @c \#include this file
+ *  in your programs, rather than any of the @a *.h implementation files.
+ *
+ *  This is the C++ version of the Standard C Library header @c locale.h,
+ *  and its contents are (mostly) the same as that header, but are all
+ *  contained in the namespace @c std (except for names which are defined
+ *  as macros in C).
+ */
+
+//
+// ISO C++ 14882: 18.2.2  Implementation properties: C library
+//
+
+#pragma GCC system_header
+
+#include <bits/c++config.h>
+#include <locale.h>
+
+#ifndef _GLIBCXX_CLOCALE
+#define _GLIBCXX_CLOCALE 1
+
+// Get rid of those macros defined in <locale.h> in lieu of real functions.
+#undef setlocale
+#undef localeconv
+
+namespace std
+{
+  using ::lconv;
+  using ::setlocale;
+  using ::localeconv;
+} // namespace std
+
+#endif
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@@ -0,0 +1,1940 @@
+// -*- C++ -*- C forwarding header.
+
+// Copyright (C) 1997-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file include/cmath
+ *  This is a Standard C++ Library file.  You should @c \#include this file
+ *  in your programs, rather than any of the @a *.h implementation files.
+ *
+ *  This is the C++ version of the Standard C Library header @c math.h,
+ *  and its contents are (mostly) the same as that header, but are all
+ *  contained in the namespace @c std (except for names which are defined
+ *  as macros in C).
+ */
+
+//
+// ISO C++ 14882: 26.5  C library
+//
+
+#pragma GCC system_header
+
+#include <bits/c++config.h>
+#include <bits/cpp_type_traits.h>
+#include <ext/type_traits.h>
+#define _GLIBCXX_INCLUDE_NEXT_C_HEADERS
+#include_next <math.h>
+#undef _GLIBCXX_INCLUDE_NEXT_C_HEADERS
+#include <bits/std_abs.h>
+
+#ifndef _GLIBCXX_CMATH
+#define _GLIBCXX_CMATH 1
+
+// Get rid of those macros defined in <math.h> in lieu of real functions.
+#undef div
+#undef acos
+#undef asin
+#undef atan
+#undef atan2
+#undef ceil
+#undef cos
+#undef cosh
+#undef exp
+#undef fabs
+#undef floor
+#undef fmod
+#undef frexp
+#undef ldexp
+#undef log
+#undef log10
+#undef modf
+#undef pow
+#undef sin
+#undef sinh
+#undef sqrt
+#undef tan
+#undef tanh
+
+extern "C++"
+{
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  using ::acos;
+
+#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
+  inline _GLIBCXX_CONSTEXPR float
+  acos(float __x)
+  { return __builtin_acosf(__x); }
+
+  inline _GLIBCXX_CONSTEXPR long double
+  acos(long double __x)
+  { return __builtin_acosl(__x); }
+#endif
+
+  template<typename _Tp>
+    inline _GLIBCXX_CONSTEXPR
+    typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
+                                    double>::__type
+    acos(_Tp __x)
+    { return __builtin_acos(__x); }
+
+  using ::asin;
+
+#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
+  inline _GLIBCXX_CONSTEXPR float
+  asin(float __x)
+  { return __builtin_asinf(__x); }
+
+  inline _GLIBCXX_CONSTEXPR long double
+  asin(long double __x)
+  { return __builtin_asinl(__x); }
+#endif
+
+  template<typename _Tp>
+    inline _GLIBCXX_CONSTEXPR
+    typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value,
+                                    double>::__type
+    asin(_Tp __x)
+    { return __builtin_asin(__x); }
+
+  using ::atan;
+
+#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
+  inline _GLIBCXX_CONSTEXPR float
+  atan(float __x)
+  { return __builtin_atanf(__x); }
+
+  inline _GLIBCXX_CONSTEXPR long double
+  atan(long double __x)
+  { return __builtin_atanl(__x); }
+#endif
+
+  template<typename _Tp>
+    inline _GLIBCXX_CONSTEXPR
+    typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value,
+                                    double>::__type
+    atan(_Tp __x)
+    { return __builtin_atan(__x); }
+
+  using ::atan2;
+
+#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
+  inline _GLIBCXX_CONSTEXPR float
+  atan2(float __y, float __x)
+  { return __builtin_atan2f(__y, __x); }
+
+  inline _GLIBCXX_CONSTEXPR long double
+  atan2(long double __y, long double __x)
+  { return __builtin_atan2l(__y, __x); }
+#endif
+
+  template<typename _Tp, typename _Up>
+    inline _GLIBCXX_CONSTEXPR
+    typename __gnu_cxx::__promote_2<_Tp, _Up>::__type
+    atan2(_Tp __y, _Up __x)
+    {
+      typedef typename __gnu_cxx::__promote_2<_Tp, _Up>::__type __type;
+      return atan2(__type(__y), __type(__x));
+    }
+
+  using ::ceil;
+
+#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
+  inline _GLIBCXX_CONSTEXPR float
+  ceil(float __x)
+  { return __builtin_ceilf(__x); }
+
+  inline _GLIBCXX_CONSTEXPR long double
+  ceil(long double __x)
+  { return __builtin_ceill(__x); }
+#endif
+
+  template<typename _Tp>
+    inline _GLIBCXX_CONSTEXPR
+    typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
+                                    double>::__type
+    ceil(_Tp __x)
+    { return __builtin_ceil(__x); }
+
+  using ::cos;
+
+#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
+  inline _GLIBCXX_CONSTEXPR float
+  cos(float __x)
+  { return __builtin_cosf(__x); }
+
+  inline _GLIBCXX_CONSTEXPR long double
+  cos(long double __x)
+  { return __builtin_cosl(__x); }
+#endif
+
+  template<typename _Tp>
+    inline _GLIBCXX_CONSTEXPR
+    typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value,
+                                    double>::__type
+    cos(_Tp __x)
+    { return __builtin_cos(__x); }
+
+  using ::cosh;
+
+#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
+  inline _GLIBCXX_CONSTEXPR float
+  cosh(float __x)
+  { return __builtin_coshf(__x); }
+
+  inline _GLIBCXX_CONSTEXPR long double
+  cosh(long double __x)
+  { return __builtin_coshl(__x); }
+#endif
+
+  template<typename _Tp>
+    inline _GLIBCXX_CONSTEXPR
+    typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value,
+                                    double>::__type
+    cosh(_Tp __x)
+    { return __builtin_cosh(__x); }
+
+  using ::exp;
+
+#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
+  inline _GLIBCXX_CONSTEXPR float
+  exp(float __x)
+  { return __builtin_expf(__x); }
+
+  inline _GLIBCXX_CONSTEXPR long double
+  exp(long double __x)
+  { return __builtin_expl(__x); }
+#endif
+
+  template<typename _Tp>
+    inline _GLIBCXX_CONSTEXPR
+    typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value,
+                                    double>::__type
+    exp(_Tp __x)
+    { return __builtin_exp(__x); }
+
+  using ::fabs;
+
+#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
+  inline _GLIBCXX_CONSTEXPR float
+  fabs(float __x)
+  { return __builtin_fabsf(__x); }
+
+  inline _GLIBCXX_CONSTEXPR long double
+  fabs(long double __x)
+  { return __builtin_fabsl(__x); }
+#endif
+
+  template<typename _Tp>
+    inline _GLIBCXX_CONSTEXPR
+    typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value,
+                                    double>::__type
+    fabs(_Tp __x)
+    { return __builtin_fabs(__x); }
+
+  using ::floor;
+
+#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
+  inline _GLIBCXX_CONSTEXPR float
+  floor(float __x)
+  { return __builtin_floorf(__x); }
+
+  inline _GLIBCXX_CONSTEXPR long double
+  floor(long double __x)
+  { return __builtin_floorl(__x); }
+#endif
+
+  template<typename _Tp>
+    inline _GLIBCXX_CONSTEXPR
+    typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value,
+                                    double>::__type
+    floor(_Tp __x)
+    { return __builtin_floor(__x); }
+
+  using ::fmod;
+
+#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
+  inline _GLIBCXX_CONSTEXPR float
+  fmod(float __x, float __y)
+  { return __builtin_fmodf(__x, __y); }
+
+  inline _GLIBCXX_CONSTEXPR long double
+  fmod(long double __x, long double __y)
+  { return __builtin_fmodl(__x, __y); }
+#endif
+
+  template<typename _Tp, typename _Up>
+    inline _GLIBCXX_CONSTEXPR
+    typename __gnu_cxx::__promote_2<_Tp, _Up>::__type
+    fmod(_Tp __x, _Up __y)
+    {
+      typedef typename __gnu_cxx::__promote_2<_Tp, _Up>::__type __type;
+      return fmod(__type(__x), __type(__y));
+    }
+
+  using ::frexp;
+
+#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
+  inline float
+  frexp(float __x, int* __exp)
+  { return __builtin_frexpf(__x, __exp); }
+
+  inline long double
+  frexp(long double __x, int* __exp)
+  { return __builtin_frexpl(__x, __exp); }
+#endif
+
+  template<typename _Tp>
+    inline _GLIBCXX_CONSTEXPR
+    typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
+                                    double>::__type
+    frexp(_Tp __x, int* __exp)
+    { return __builtin_frexp(__x, __exp); }
+
+  using ::ldexp;
+
+#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
+  inline _GLIBCXX_CONSTEXPR float
+  ldexp(float __x, int __exp)
+  { return __builtin_ldexpf(__x, __exp); }
+
+  inline _GLIBCXX_CONSTEXPR long double
+  ldexp(long double __x, int __exp)
+  { return __builtin_ldexpl(__x, __exp); }
+#endif
+
+  template<typename _Tp>
+    inline _GLIBCXX_CONSTEXPR
+    typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
+                                    double>::__type
+    ldexp(_Tp __x, int __exp)
+    { return __builtin_ldexp(__x, __exp); }
+
+  using ::log;
+
+#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
+  inline _GLIBCXX_CONSTEXPR float
+  log(float __x)
+  { return __builtin_logf(__x); }
+
+  inline _GLIBCXX_CONSTEXPR long double
+  log(long double __x)
+  { return __builtin_logl(__x); }
+#endif
+
+  template<typename _Tp>
+    inline _GLIBCXX_CONSTEXPR
+    typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
+                                    double>::__type
+    log(_Tp __x)
+    { return __builtin_log(__x); }
+
+  using ::log10;
+
+#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
+  inline _GLIBCXX_CONSTEXPR float
+  log10(float __x)
+  { return __builtin_log10f(__x); }
+
+  inline _GLIBCXX_CONSTEXPR long double
+  log10(long double __x)
+  { return __builtin_log10l(__x); }
+#endif
+
+  template<typename _Tp>
+    inline _GLIBCXX_CONSTEXPR
+    typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value,
+                                    double>::__type
+    log10(_Tp __x)
+    { return __builtin_log10(__x); }
+
+  using ::modf;
+
+#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
+  inline float
+  modf(float __x, float* __iptr)
+  { return __builtin_modff(__x, __iptr); }
+
+  inline long double
+  modf(long double __x, long double* __iptr)
+  { return __builtin_modfl(__x, __iptr); }
+#endif
+
+  using ::pow;
+
+#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
+  inline _GLIBCXX_CONSTEXPR float
+  pow(float __x, float __y)
+  { return __builtin_powf(__x, __y); }
+
+  inline _GLIBCXX_CONSTEXPR long double
+  pow(long double __x, long double __y)
+  { return __builtin_powl(__x, __y); }
+
+#if __cplusplus < 201103L
+  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+  // DR 550. What should the return type of pow(float,int) be?
+  inline double
+  pow(double __x, int __i)
+  { return __builtin_powi(__x, __i); }
+
+  inline float
+  pow(float __x, int __n)
+  { return __builtin_powif(__x, __n); }
+
+  inline long double
+  pow(long double __x, int __n)
+  { return __builtin_powil(__x, __n); }
+#endif
+#endif
+
+  template<typename _Tp, typename _Up>
+    inline _GLIBCXX_CONSTEXPR
+    typename __gnu_cxx::__promote_2<_Tp, _Up>::__type
+    pow(_Tp __x, _Up __y)
+    {
+      typedef typename __gnu_cxx::__promote_2<_Tp, _Up>::__type __type;
+      return pow(__type(__x), __type(__y));
+    }
+
+  using ::sin;
+
+#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
+  inline _GLIBCXX_CONSTEXPR float
+  sin(float __x)
+  { return __builtin_sinf(__x); }
+
+  inline _GLIBCXX_CONSTEXPR long double
+  sin(long double __x)
+  { return __builtin_sinl(__x); }
+#endif
+
+  template<typename _Tp>
+    inline _GLIBCXX_CONSTEXPR
+    typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
+                                    double>::__type
+    sin(_Tp __x)
+    { return __builtin_sin(__x); }
+
+  using ::sinh;
+
+#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
+  inline _GLIBCXX_CONSTEXPR float
+  sinh(float __x)
+  { return __builtin_sinhf(__x); }
+
+  inline _GLIBCXX_CONSTEXPR long double
+  sinh(long double __x)
+  { return __builtin_sinhl(__x); }
+#endif
+
+  template<typename _Tp>
+    inline _GLIBCXX_CONSTEXPR
+    typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
+                                    double>::__type
+    sinh(_Tp __x)
+    { return __builtin_sinh(__x); }
+
+  using ::sqrt;
+
+#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
+  inline _GLIBCXX_CONSTEXPR float
+  sqrt(float __x)
+  { return __builtin_sqrtf(__x); }
+
+  inline _GLIBCXX_CONSTEXPR long double
+  sqrt(long double __x)
+  { return __builtin_sqrtl(__x); }
+#endif
+
+  template<typename _Tp>
+    inline _GLIBCXX_CONSTEXPR
+    typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
+                                    double>::__type
+    sqrt(_Tp __x)
+    { return __builtin_sqrt(__x); }
+
+  using ::tan;
+
+#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
+  inline _GLIBCXX_CONSTEXPR float
+  tan(float __x)
+  { return __builtin_tanf(__x); }
+
+  inline _GLIBCXX_CONSTEXPR long double
+  tan(long double __x)
+  { return __builtin_tanl(__x); }
+#endif
+
+  template<typename _Tp>
+    inline _GLIBCXX_CONSTEXPR
+    typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
+                                    double>::__type
+    tan(_Tp __x)
+    { return __builtin_tan(__x); }
+
+  using ::tanh;
+
+#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
+  inline _GLIBCXX_CONSTEXPR float
+  tanh(float __x)
+  { return __builtin_tanhf(__x); }
+
+  inline _GLIBCXX_CONSTEXPR long double
+  tanh(long double __x)
+  { return __builtin_tanhl(__x); }
+#endif
+
+  template<typename _Tp>
+    inline _GLIBCXX_CONSTEXPR
+    typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
+                                    double>::__type
+    tanh(_Tp __x)
+    { return __builtin_tanh(__x); }
+
+#if _GLIBCXX_USE_C99_MATH
+#if !_GLIBCXX_USE_C99_FP_MACROS_DYNAMIC
+
+// These are possible macros imported from C99-land.
+#undef fpclassify
+#undef isfinite
+#undef isinf
+#undef isnan
+#undef isnormal
+#undef signbit
+#undef isgreater
+#undef isgreaterequal
+#undef isless
+#undef islessequal
+#undef islessgreater
+#undef isunordered
+
+#if __cplusplus >= 201103L
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
+  constexpr int
+  fpclassify(float __x)
+  { return __builtin_fpclassify(FP_NAN, FP_INFINITE, FP_NORMAL,
+				FP_SUBNORMAL, FP_ZERO, __x); }
+
+  constexpr int
+  fpclassify(double __x)
+  { return __builtin_fpclassify(FP_NAN, FP_INFINITE, FP_NORMAL,
+				FP_SUBNORMAL, FP_ZERO, __x); }
+
+  constexpr int
+  fpclassify(long double __x)
+  { return __builtin_fpclassify(FP_NAN, FP_INFINITE, FP_NORMAL,
+				FP_SUBNORMAL, FP_ZERO, __x); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
+  template<typename _Tp>
+    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value,
+                                              int>::__type
+    fpclassify(_Tp __x)
+    { return __x != 0 ? FP_NORMAL : FP_ZERO; }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
+  constexpr bool
+  isfinite(float __x)
+  { return __builtin_isfinite(__x); }
+
+  constexpr bool
+  isfinite(double __x)
+  { return __builtin_isfinite(__x); }
+
+  constexpr bool
+  isfinite(long double __x)
+  { return __builtin_isfinite(__x); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
+  template<typename _Tp>
+    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value,
+                                              bool>::__type
+    isfinite(_Tp __x)
+    { return true; }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
+  constexpr bool
+  isinf(float __x)
+  { return __builtin_isinf(__x); }
+
+#if _GLIBCXX_HAVE_OBSOLETE_ISINF \
+  && !_GLIBCXX_NO_OBSOLETE_ISINF_ISNAN_DYNAMIC
+  using ::isinf;
+#else
+  constexpr bool
+  isinf(double __x)
+  { return __builtin_isinf(__x); }
+#endif
+
+  constexpr bool
+  isinf(long double __x)
+  { return __builtin_isinf(__x); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
+  template<typename _Tp>
+    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value,
+                                              bool>::__type
+    isinf(_Tp __x)
+    { return false; }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
+  constexpr bool
+  isnan(float __x)
+  { return __builtin_isnan(__x); }
+
+#if _GLIBCXX_HAVE_OBSOLETE_ISNAN \
+  && !_GLIBCXX_NO_OBSOLETE_ISINF_ISNAN_DYNAMIC
+  using ::isnan;
+#else
+  constexpr bool
+  isnan(double __x)
+  { return __builtin_isnan(__x); }
+#endif
+
+  constexpr bool
+  isnan(long double __x)
+  { return __builtin_isnan(__x); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
+  template<typename _Tp>
+    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value,
+                                              bool>::__type
+    isnan(_Tp __x)
+    { return false; }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
+  constexpr bool
+  isnormal(float __x)
+  { return __builtin_isnormal(__x); }
+
+  constexpr bool
+  isnormal(double __x)
+  { return __builtin_isnormal(__x); }
+
+  constexpr bool
+  isnormal(long double __x)
+  { return __builtin_isnormal(__x); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
+  template<typename _Tp>
+    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value,
+                                              bool>::__type
+    isnormal(_Tp __x)
+    { return __x != 0 ? true : false; }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
+  // Note: middle-end/36757 is fixed, __builtin_signbit is type-generic.
+  constexpr bool
+  signbit(float __x)
+  { return __builtin_signbit(__x); }
+
+  constexpr bool
+  signbit(double __x)
+  { return __builtin_signbit(__x); }
+
+  constexpr bool
+  signbit(long double __x)
+  { return __builtin_signbit(__x); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
+  template<typename _Tp>
+    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value,
+                                              bool>::__type
+    signbit(_Tp __x)
+    { return __x < 0 ? true : false; }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
+  constexpr bool
+  isgreater(float __x, float __y)
+  { return __builtin_isgreater(__x, __y); }
+
+  constexpr bool
+  isgreater(double __x, double __y)
+  { return __builtin_isgreater(__x, __y); }
+
+  constexpr bool
+  isgreater(long double __x, long double __y)
+  { return __builtin_isgreater(__x, __y); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
+  template<typename _Tp, typename _Up>
+    constexpr typename
+    __gnu_cxx::__enable_if<(__is_arithmetic<_Tp>::__value
+			    && __is_arithmetic<_Up>::__value), bool>::__type
+    isgreater(_Tp __x, _Up __y)
+    {
+      typedef typename __gnu_cxx::__promote_2<_Tp, _Up>::__type __type;
+      return __builtin_isgreater(__type(__x), __type(__y));
+    }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
+  constexpr bool
+  isgreaterequal(float __x, float __y)
+  { return __builtin_isgreaterequal(__x, __y); }
+
+  constexpr bool
+  isgreaterequal(double __x, double __y)
+  { return __builtin_isgreaterequal(__x, __y); }
+
+  constexpr bool
+  isgreaterequal(long double __x, long double __y)
+  { return __builtin_isgreaterequal(__x, __y); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
+  template<typename _Tp, typename _Up>
+    constexpr typename
+    __gnu_cxx::__enable_if<(__is_arithmetic<_Tp>::__value
+			    && __is_arithmetic<_Up>::__value), bool>::__type
+    isgreaterequal(_Tp __x, _Up __y)
+    {
+      typedef typename __gnu_cxx::__promote_2<_Tp, _Up>::__type __type;
+      return __builtin_isgreaterequal(__type(__x), __type(__y));
+    }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
+  constexpr bool
+  isless(float __x, float __y)
+  { return __builtin_isless(__x, __y); }
+
+  constexpr bool
+  isless(double __x, double __y)
+  { return __builtin_isless(__x, __y); }
+
+  constexpr bool
+  isless(long double __x, long double __y)
+  { return __builtin_isless(__x, __y); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
+  template<typename _Tp, typename _Up>
+    constexpr typename
+    __gnu_cxx::__enable_if<(__is_arithmetic<_Tp>::__value
+			    && __is_arithmetic<_Up>::__value), bool>::__type
+    isless(_Tp __x, _Up __y)
+    {
+      typedef typename __gnu_cxx::__promote_2<_Tp, _Up>::__type __type;
+      return __builtin_isless(__type(__x), __type(__y));
+    }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
+  constexpr bool
+  islessequal(float __x, float __y)
+  { return __builtin_islessequal(__x, __y); }
+
+  constexpr bool
+  islessequal(double __x, double __y)
+  { return __builtin_islessequal(__x, __y); }
+
+  constexpr bool
+  islessequal(long double __x, long double __y)
+  { return __builtin_islessequal(__x, __y); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
+  template<typename _Tp, typename _Up>
+    constexpr typename
+    __gnu_cxx::__enable_if<(__is_arithmetic<_Tp>::__value
+			    && __is_arithmetic<_Up>::__value), bool>::__type
+    islessequal(_Tp __x, _Up __y)
+    {
+      typedef typename __gnu_cxx::__promote_2<_Tp, _Up>::__type __type;
+      return __builtin_islessequal(__type(__x), __type(__y));
+    }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
+  constexpr bool
+  islessgreater(float __x, float __y)
+  { return __builtin_islessgreater(__x, __y); }
+
+  constexpr bool
+  islessgreater(double __x, double __y)
+  { return __builtin_islessgreater(__x, __y); }
+
+  constexpr bool
+  islessgreater(long double __x, long double __y)
+  { return __builtin_islessgreater(__x, __y); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
+  template<typename _Tp, typename _Up>
+    constexpr typename
+    __gnu_cxx::__enable_if<(__is_arithmetic<_Tp>::__value
+			    && __is_arithmetic<_Up>::__value), bool>::__type
+    islessgreater(_Tp __x, _Up __y)
+    {
+      typedef typename __gnu_cxx::__promote_2<_Tp, _Up>::__type __type;
+      return __builtin_islessgreater(__type(__x), __type(__y));
+    }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
+  constexpr bool
+  isunordered(float __x, float __y)
+  { return __builtin_isunordered(__x, __y); }
+
+  constexpr bool
+  isunordered(double __x, double __y)
+  { return __builtin_isunordered(__x, __y); }
+
+  constexpr bool
+  isunordered(long double __x, long double __y)
+  { return __builtin_isunordered(__x, __y); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
+  template<typename _Tp, typename _Up>
+    constexpr typename
+    __gnu_cxx::__enable_if<(__is_arithmetic<_Tp>::__value
+			    && __is_arithmetic<_Up>::__value), bool>::__type
+    isunordered(_Tp __x, _Up __y)
+    {
+      typedef typename __gnu_cxx::__promote_2<_Tp, _Up>::__type __type;
+      return __builtin_isunordered(__type(__x), __type(__y));
+    }
+#endif
+
+#else
+
+  template<typename _Tp>
+    inline typename __gnu_cxx::__enable_if<__is_arithmetic<_Tp>::__value,
+					   int>::__type
+    fpclassify(_Tp __f)
+    {
+      typedef typename __gnu_cxx::__promote<_Tp>::__type __type;
+      return __builtin_fpclassify(FP_NAN, FP_INFINITE, FP_NORMAL,
+				  FP_SUBNORMAL, FP_ZERO, __type(__f));
+    }
+
+  template<typename _Tp>
+    inline typename __gnu_cxx::__enable_if<__is_arithmetic<_Tp>::__value,
+					   int>::__type
+    isfinite(_Tp __f)
+    {
+      typedef typename __gnu_cxx::__promote<_Tp>::__type __type;
+      return __builtin_isfinite(__type(__f));
+    }
+
+  template<typename _Tp>
+    inline typename __gnu_cxx::__enable_if<__is_arithmetic<_Tp>::__value,
+					   int>::__type
+    isinf(_Tp __f)
+    {
+      typedef typename __gnu_cxx::__promote<_Tp>::__type __type;
+      return __builtin_isinf(__type(__f));
+    }
+
+  template<typename _Tp>
+    inline typename __gnu_cxx::__enable_if<__is_arithmetic<_Tp>::__value,
+					   int>::__type
+    isnan(_Tp __f)
+    {
+      typedef typename __gnu_cxx::__promote<_Tp>::__type __type;
+      return __builtin_isnan(__type(__f));
+    }
+
+  template<typename _Tp>
+    inline typename __gnu_cxx::__enable_if<__is_arithmetic<_Tp>::__value,
+					   int>::__type
+    isnormal(_Tp __f)
+    {
+      typedef typename __gnu_cxx::__promote<_Tp>::__type __type;
+      return __builtin_isnormal(__type(__f));
+    }
+
+  template<typename _Tp>
+    inline typename __gnu_cxx::__enable_if<__is_arithmetic<_Tp>::__value,
+					   int>::__type
+    signbit(_Tp __f)
+    {
+      typedef typename __gnu_cxx::__promote<_Tp>::__type __type;
+      return __builtin_signbit(__type(__f));
+    }
+
+  template<typename _Tp>
+    inline typename __gnu_cxx::__enable_if<__is_arithmetic<_Tp>::__value,
+					   int>::__type
+    isgreater(_Tp __f1, _Tp __f2)
+    {
+      typedef typename __gnu_cxx::__promote<_Tp>::__type __type;
+      return __builtin_isgreater(__type(__f1), __type(__f2));
+    }
+
+  template<typename _Tp>
+    inline typename __gnu_cxx::__enable_if<__is_arithmetic<_Tp>::__value,
+					   int>::__type
+    isgreaterequal(_Tp __f1, _Tp __f2)
+    {
+      typedef typename __gnu_cxx::__promote<_Tp>::__type __type;
+      return __builtin_isgreaterequal(__type(__f1), __type(__f2));
+    }
+
+  template<typename _Tp>
+    inline typename __gnu_cxx::__enable_if<__is_arithmetic<_Tp>::__value,
+					   int>::__type
+    isless(_Tp __f1, _Tp __f2)
+    {
+      typedef typename __gnu_cxx::__promote<_Tp>::__type __type;
+      return __builtin_isless(__type(__f1), __type(__f2));
+    }
+
+  template<typename _Tp>
+    inline typename __gnu_cxx::__enable_if<__is_arithmetic<_Tp>::__value,
+					   int>::__type
+    islessequal(_Tp __f1, _Tp __f2)
+    {
+      typedef typename __gnu_cxx::__promote<_Tp>::__type __type;
+      return __builtin_islessequal(__type(__f1), __type(__f2));
+    }
+
+  template<typename _Tp>
+    inline typename __gnu_cxx::__enable_if<__is_arithmetic<_Tp>::__value,
+					   int>::__type
+    islessgreater(_Tp __f1, _Tp __f2)
+    {
+      typedef typename __gnu_cxx::__promote<_Tp>::__type __type;
+      return __builtin_islessgreater(__type(__f1), __type(__f2));
+    }
+
+  template<typename _Tp>
+    inline typename __gnu_cxx::__enable_if<__is_arithmetic<_Tp>::__value,
+					   int>::__type
+    isunordered(_Tp __f1, _Tp __f2)
+    {
+      typedef typename __gnu_cxx::__promote<_Tp>::__type __type;
+      return __builtin_isunordered(__type(__f1), __type(__f2));
+    }
+
+#endif // C++11
+#endif /* _GLIBCXX_USE_C99_FP_MACROS_DYNAMIC */
+#endif /* _GLIBCXX_USE_C99_MATH */
+
+#if __cplusplus >= 201103L
+
+#ifdef _GLIBCXX_USE_C99_MATH_TR1
+
+#undef acosh
+#undef acoshf
+#undef acoshl
+#undef asinh
+#undef asinhf
+#undef asinhl
+#undef atanh
+#undef atanhf
+#undef atanhl
+#undef cbrt
+#undef cbrtf
+#undef cbrtl
+#undef copysign
+#undef copysignf
+#undef copysignl
+#undef erf
+#undef erff
+#undef erfl
+#undef erfc
+#undef erfcf
+#undef erfcl
+#undef exp2
+#undef exp2f
+#undef exp2l
+#undef expm1
+#undef expm1f
+#undef expm1l
+#undef fdim
+#undef fdimf
+#undef fdiml
+#undef fma
+#undef fmaf
+#undef fmal
+#undef fmax
+#undef fmaxf
+#undef fmaxl
+#undef fmin
+#undef fminf
+#undef fminl
+#undef hypot
+#undef hypotf
+#undef hypotl
+#undef ilogb
+#undef ilogbf
+#undef ilogbl
+#undef lgamma
+#undef lgammaf
+#undef lgammal
+#ifndef _GLIBCXX_NO_C99_ROUNDING_FUNCS
+#undef llrint
+#undef llrintf
+#undef llrintl
+#undef llround
+#undef llroundf
+#undef llroundl
+#endif
+#undef log1p
+#undef log1pf
+#undef log1pl
+#undef log2
+#undef log2f
+#undef log2l
+#undef logb
+#undef logbf
+#undef logbl
+#undef lrint
+#undef lrintf
+#undef lrintl
+#undef lround
+#undef lroundf
+#undef lroundl
+#undef nan
+#undef nanf
+#undef nanl
+#undef nearbyint
+#undef nearbyintf
+#undef nearbyintl
+#undef nextafter
+#undef nextafterf
+#undef nextafterl
+#undef nexttoward
+#undef nexttowardf
+#undef nexttowardl
+#undef remainder
+#undef remainderf
+#undef remainderl
+#undef remquo
+#undef remquof
+#undef remquol
+#undef rint
+#undef rintf
+#undef rintl
+#undef round
+#undef roundf
+#undef roundl
+#undef scalbln
+#undef scalblnf
+#undef scalblnl
+#undef scalbn
+#undef scalbnf
+#undef scalbnl
+#undef tgamma
+#undef tgammaf
+#undef tgammal
+#undef trunc
+#undef truncf
+#undef truncl
+
+  // types
+  using ::double_t;
+  using ::float_t;
+
+  // functions
+  using ::acosh;
+  using ::acoshf;
+  using ::acoshl;
+
+  using ::asinh;
+  using ::asinhf;
+  using ::asinhl;
+
+  using ::atanh;
+  using ::atanhf;
+  using ::atanhl;
+
+  using ::cbrt;
+  using ::cbrtf;
+  using ::cbrtl;
+
+  using ::copysign;
+  using ::copysignf;
+  using ::copysignl;
+
+  using ::erf;
+  using ::erff;
+  using ::erfl;
+
+  using ::erfc;
+  using ::erfcf;
+  using ::erfcl;
+
+  using ::exp2;
+  using ::exp2f;
+  using ::exp2l;
+
+  using ::expm1;
+  using ::expm1f;
+  using ::expm1l;
+
+  using ::fdim;
+  using ::fdimf;
+  using ::fdiml;
+
+  using ::fma;
+  using ::fmaf;
+  using ::fmal;
+
+  using ::fmax;
+  using ::fmaxf;
+  using ::fmaxl;
+
+  using ::fmin;
+  using ::fminf;
+  using ::fminl;
+
+  using ::hypot;
+  using ::hypotf;
+  using ::hypotl;
+
+  using ::ilogb;
+  using ::ilogbf;
+  using ::ilogbl;
+
+  using ::lgamma;
+  using ::lgammaf;
+  using ::lgammal;
+
+#ifndef _GLIBCXX_NO_C99_ROUNDING_FUNCS
+  using ::llrint;
+  using ::llrintf;
+  using ::llrintl;
+
+  using ::llround;
+  using ::llroundf;
+  using ::llroundl;
+#endif
+
+  using ::log1p;
+  using ::log1pf;
+  using ::log1pl;
+
+  using ::log2;
+  using ::log2f;
+  using ::log2l;
+
+  using ::logb;
+  using ::logbf;
+  using ::logbl;
+
+  using ::lrint;
+  using ::lrintf;
+  using ::lrintl;
+
+  using ::lround;
+  using ::lroundf;
+  using ::lroundl;
+
+  using ::nan;
+  using ::nanf;
+  using ::nanl;
+
+  using ::nearbyint;
+  using ::nearbyintf;
+  using ::nearbyintl;
+
+  using ::nextafter;
+  using ::nextafterf;
+  using ::nextafterl;
+
+  using ::nexttoward;
+  using ::nexttowardf;
+  using ::nexttowardl;
+
+  using ::remainder;
+  using ::remainderf;
+  using ::remainderl;
+
+  using ::remquo;
+  using ::remquof;
+  using ::remquol;
+
+  using ::rint;
+  using ::rintf;
+  using ::rintl;
+
+  using ::round;
+  using ::roundf;
+  using ::roundl;
+
+  using ::scalbln;
+  using ::scalblnf;
+  using ::scalblnl;
+
+  using ::scalbn;
+  using ::scalbnf;
+  using ::scalbnl;
+
+  using ::tgamma;
+  using ::tgammaf;
+  using ::tgammal;
+
+  using ::trunc;
+  using ::truncf;
+  using ::truncl;
+
+  /// Additional overloads.
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
+  constexpr float
+  acosh(float __x)
+  { return __builtin_acoshf(__x); }
+
+  constexpr long double
+  acosh(long double __x)
+  { return __builtin_acoshl(__x); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
+  template<typename _Tp>
+    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
+                                              double>::__type
+    acosh(_Tp __x)
+    { return __builtin_acosh(__x); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
+  constexpr float
+  asinh(float __x)
+  { return __builtin_asinhf(__x); }
+
+  constexpr long double
+  asinh(long double __x)
+  { return __builtin_asinhl(__x); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
+  template<typename _Tp>
+    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
+                                              double>::__type
+    asinh(_Tp __x)
+    { return __builtin_asinh(__x); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
+  constexpr float
+  atanh(float __x)
+  { return __builtin_atanhf(__x); }
+
+  constexpr long double
+  atanh(long double __x)
+  { return __builtin_atanhl(__x); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
+  template<typename _Tp>
+    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
+                                              double>::__type
+    atanh(_Tp __x)
+    { return __builtin_atanh(__x); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
+  constexpr float
+  cbrt(float __x)
+  { return __builtin_cbrtf(__x); }
+
+  constexpr long double
+  cbrt(long double __x)
+  { return __builtin_cbrtl(__x); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
+  template<typename _Tp>
+    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
+                                              double>::__type
+    cbrt(_Tp __x)
+    { return __builtin_cbrt(__x); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
+  constexpr float
+  copysign(float __x, float __y)
+  { return __builtin_copysignf(__x, __y); }
+
+  constexpr long double
+  copysign(long double __x, long double __y)
+  { return __builtin_copysignl(__x, __y); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
+  template<typename _Tp, typename _Up>
+    constexpr typename __gnu_cxx::__promote_2<_Tp, _Up>::__type
+    copysign(_Tp __x, _Up __y)
+    {
+      typedef typename __gnu_cxx::__promote_2<_Tp, _Up>::__type __type;
+      return copysign(__type(__x), __type(__y));
+    }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
+  constexpr float
+  erf(float __x)
+  { return __builtin_erff(__x); }
+
+  constexpr long double
+  erf(long double __x)
+  { return __builtin_erfl(__x); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
+  template<typename _Tp>
+    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
+                                              double>::__type
+    erf(_Tp __x)
+    { return __builtin_erf(__x); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
+  constexpr float
+  erfc(float __x)
+  { return __builtin_erfcf(__x); }
+
+  constexpr long double
+  erfc(long double __x)
+  { return __builtin_erfcl(__x); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
+  template<typename _Tp>
+    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
+                                              double>::__type
+    erfc(_Tp __x)
+    { return __builtin_erfc(__x); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
+  constexpr float
+  exp2(float __x)
+  { return __builtin_exp2f(__x); }
+
+  constexpr long double
+  exp2(long double __x)
+  { return __builtin_exp2l(__x); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
+  template<typename _Tp>
+    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
+                                              double>::__type
+    exp2(_Tp __x)
+    { return __builtin_exp2(__x); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
+  constexpr float
+  expm1(float __x)
+  { return __builtin_expm1f(__x); }
+
+  constexpr long double
+  expm1(long double __x)
+  { return __builtin_expm1l(__x); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
+  template<typename _Tp>
+    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
+                                              double>::__type
+    expm1(_Tp __x)
+    { return __builtin_expm1(__x); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
+  constexpr float
+  fdim(float __x, float __y)
+  { return __builtin_fdimf(__x, __y); }
+
+  constexpr long double
+  fdim(long double __x, long double __y)
+  { return __builtin_fdiml(__x, __y); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
+  template<typename _Tp, typename _Up>
+    constexpr typename __gnu_cxx::__promote_2<_Tp, _Up>::__type
+    fdim(_Tp __x, _Up __y)
+    {
+      typedef typename __gnu_cxx::__promote_2<_Tp, _Up>::__type __type;
+      return fdim(__type(__x), __type(__y));
+    }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
+  constexpr float
+  fma(float __x, float __y, float __z)
+  { return __builtin_fmaf(__x, __y, __z); }
+
+  constexpr long double
+  fma(long double __x, long double __y, long double __z)
+  { return __builtin_fmal(__x, __y, __z); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
+  template<typename _Tp, typename _Up, typename _Vp>
+    constexpr typename __gnu_cxx::__promote_3<_Tp, _Up, _Vp>::__type
+    fma(_Tp __x, _Up __y, _Vp __z)
+    {
+      typedef typename __gnu_cxx::__promote_3<_Tp, _Up, _Vp>::__type __type;
+      return fma(__type(__x), __type(__y), __type(__z));
+    }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
+  constexpr float
+  fmax(float __x, float __y)
+  { return __builtin_fmaxf(__x, __y); }
+
+  constexpr long double
+  fmax(long double __x, long double __y)
+  { return __builtin_fmaxl(__x, __y); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
+  template<typename _Tp, typename _Up>
+    constexpr typename __gnu_cxx::__promote_2<_Tp, _Up>::__type
+    fmax(_Tp __x, _Up __y)
+    {
+      typedef typename __gnu_cxx::__promote_2<_Tp, _Up>::__type __type;
+      return fmax(__type(__x), __type(__y));
+    }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
+  constexpr float
+  fmin(float __x, float __y)
+  { return __builtin_fminf(__x, __y); }
+
+  constexpr long double
+  fmin(long double __x, long double __y)
+  { return __builtin_fminl(__x, __y); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
+  template<typename _Tp, typename _Up>
+    constexpr typename __gnu_cxx::__promote_2<_Tp, _Up>::__type
+    fmin(_Tp __x, _Up __y)
+    {
+      typedef typename __gnu_cxx::__promote_2<_Tp, _Up>::__type __type;
+      return fmin(__type(__x), __type(__y));
+    }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
+  constexpr float
+  hypot(float __x, float __y)
+  { return __builtin_hypotf(__x, __y); }
+
+  constexpr long double
+  hypot(long double __x, long double __y)
+  { return __builtin_hypotl(__x, __y); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
+  template<typename _Tp, typename _Up>
+    constexpr typename __gnu_cxx::__promote_2<_Tp, _Up>::__type
+    hypot(_Tp __x, _Up __y)
+    {
+      typedef typename __gnu_cxx::__promote_2<_Tp, _Up>::__type __type;
+      return hypot(__type(__x), __type(__y));
+    }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
+  constexpr int
+  ilogb(float __x)
+  { return __builtin_ilogbf(__x); }
+
+  constexpr int
+  ilogb(long double __x)
+  { return __builtin_ilogbl(__x); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
+  template<typename _Tp>
+    constexpr
+    typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
+                                    int>::__type
+    ilogb(_Tp __x)
+    { return __builtin_ilogb(__x); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
+  constexpr float
+  lgamma(float __x)
+  { return __builtin_lgammaf(__x); }
+
+  constexpr long double
+  lgamma(long double __x)
+  { return __builtin_lgammal(__x); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
+  template<typename _Tp>
+    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
+                                              double>::__type
+    lgamma(_Tp __x)
+    { return __builtin_lgamma(__x); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
+  constexpr long long
+  llrint(float __x)
+  { return __builtin_llrintf(__x); }
+
+  constexpr long long
+  llrint(long double __x)
+  { return __builtin_llrintl(__x); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
+  template<typename _Tp>
+    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
+                                              long long>::__type
+    llrint(_Tp __x)
+    { return __builtin_llrint(__x); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
+  constexpr long long
+  llround(float __x)
+  { return __builtin_llroundf(__x); }
+
+  constexpr long long
+  llround(long double __x)
+  { return __builtin_llroundl(__x); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
+  template<typename _Tp>
+    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
+                                              long long>::__type
+    llround(_Tp __x)
+    { return __builtin_llround(__x); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
+  constexpr float
+  log1p(float __x)
+  { return __builtin_log1pf(__x); }
+
+  constexpr long double
+  log1p(long double __x)
+  { return __builtin_log1pl(__x); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
+  template<typename _Tp>
+    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
+                                              double>::__type
+    log1p(_Tp __x)
+    { return __builtin_log1p(__x); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
+  // DR 568.
+  constexpr float
+  log2(float __x)
+  { return __builtin_log2f(__x); }
+
+  constexpr long double
+  log2(long double __x)
+  { return __builtin_log2l(__x); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
+  template<typename _Tp>
+    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
+                                              double>::__type
+    log2(_Tp __x)
+    { return __builtin_log2(__x); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
+  constexpr float
+  logb(float __x)
+  { return __builtin_logbf(__x); }
+
+  constexpr long double
+  logb(long double __x)
+  { return __builtin_logbl(__x); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
+  template<typename _Tp>
+    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
+                                              double>::__type
+    logb(_Tp __x)
+    { return __builtin_logb(__x); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
+  constexpr long
+  lrint(float __x)
+  { return __builtin_lrintf(__x); }
+
+  constexpr long
+  lrint(long double __x)
+  { return __builtin_lrintl(__x); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
+  template<typename _Tp>
+    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
+                                              long>::__type
+    lrint(_Tp __x)
+    { return __builtin_lrint(__x); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
+  constexpr long
+  lround(float __x)
+  { return __builtin_lroundf(__x); }
+
+  constexpr long
+  lround(long double __x)
+  { return __builtin_lroundl(__x); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
+  template<typename _Tp>
+    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
+                                              long>::__type
+    lround(_Tp __x)
+    { return __builtin_lround(__x); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
+  constexpr float
+  nearbyint(float __x)
+  { return __builtin_nearbyintf(__x); }
+
+  constexpr long double
+  nearbyint(long double __x)
+  { return __builtin_nearbyintl(__x); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
+  template<typename _Tp>
+    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
+                                              double>::__type
+    nearbyint(_Tp __x)
+    { return __builtin_nearbyint(__x); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
+  constexpr float
+  nextafter(float __x, float __y)
+  { return __builtin_nextafterf(__x, __y); }
+
+  constexpr long double
+  nextafter(long double __x, long double __y)
+  { return __builtin_nextafterl(__x, __y); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
+  template<typename _Tp, typename _Up>
+    constexpr typename __gnu_cxx::__promote_2<_Tp, _Up>::__type
+    nextafter(_Tp __x, _Up __y)
+    {
+      typedef typename __gnu_cxx::__promote_2<_Tp, _Up>::__type __type;
+      return nextafter(__type(__x), __type(__y));
+    }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
+  constexpr float
+  nexttoward(float __x, long double __y)
+  { return __builtin_nexttowardf(__x, __y); }
+
+  constexpr long double
+  nexttoward(long double __x, long double __y)
+  { return __builtin_nexttowardl(__x, __y); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
+  template<typename _Tp>
+    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
+                                              double>::__type
+    nexttoward(_Tp __x, long double __y)
+    { return __builtin_nexttoward(__x, __y); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
+  constexpr float
+  remainder(float __x, float __y)
+  { return __builtin_remainderf(__x, __y); }
+
+  constexpr long double
+  remainder(long double __x, long double __y)
+  { return __builtin_remainderl(__x, __y); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
+  template<typename _Tp, typename _Up>
+    constexpr typename __gnu_cxx::__promote_2<_Tp, _Up>::__type
+    remainder(_Tp __x, _Up __y)
+    {
+      typedef typename __gnu_cxx::__promote_2<_Tp, _Up>::__type __type;
+      return remainder(__type(__x), __type(__y));
+    }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
+  inline float
+  remquo(float __x, float __y, int* __pquo)
+  { return __builtin_remquof(__x, __y, __pquo); }
+
+  inline long double
+  remquo(long double __x, long double __y, int* __pquo)
+  { return __builtin_remquol(__x, __y, __pquo); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
+  template<typename _Tp, typename _Up>
+    inline typename __gnu_cxx::__promote_2<_Tp, _Up>::__type
+    remquo(_Tp __x, _Up __y, int* __pquo)
+    {
+      typedef typename __gnu_cxx::__promote_2<_Tp, _Up>::__type __type;
+      return remquo(__type(__x), __type(__y), __pquo);
+    }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
+  constexpr float
+  rint(float __x)
+  { return __builtin_rintf(__x); }
+
+  constexpr long double
+  rint(long double __x)
+  { return __builtin_rintl(__x); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
+  template<typename _Tp>
+    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
+                                              double>::__type
+    rint(_Tp __x)
+    { return __builtin_rint(__x); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
+  constexpr float
+  round(float __x)
+  { return __builtin_roundf(__x); }
+
+  constexpr long double
+  round(long double __x)
+  { return __builtin_roundl(__x); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
+  template<typename _Tp>
+    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
+                                              double>::__type
+    round(_Tp __x)
+    { return __builtin_round(__x); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
+  constexpr float
+  scalbln(float __x, long __ex)
+  { return __builtin_scalblnf(__x, __ex); }
+
+  constexpr long double
+  scalbln(long double __x, long __ex)
+  { return __builtin_scalblnl(__x, __ex); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
+  template<typename _Tp>
+    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
+                                              double>::__type
+    scalbln(_Tp __x, long __ex)
+    { return __builtin_scalbln(__x, __ex); }
+#endif
+ 
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
+  constexpr float
+  scalbn(float __x, int __ex)
+  { return __builtin_scalbnf(__x, __ex); }
+
+  constexpr long double
+  scalbn(long double __x, int __ex)
+  { return __builtin_scalbnl(__x, __ex); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
+  template<typename _Tp>
+    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
+                                              double>::__type
+    scalbn(_Tp __x, int __ex)
+    { return __builtin_scalbn(__x, __ex); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
+  constexpr float
+  tgamma(float __x)
+  { return __builtin_tgammaf(__x); }
+
+  constexpr long double
+  tgamma(long double __x)
+  { return __builtin_tgammal(__x); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
+  template<typename _Tp>
+    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
+                                              double>::__type
+    tgamma(_Tp __x)
+    { return __builtin_tgamma(__x); }
+#endif
+ 
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
+  constexpr float
+  trunc(float __x)
+  { return __builtin_truncf(__x); }
+
+  constexpr long double
+  trunc(long double __x)
+  { return __builtin_truncl(__x); }
+#endif
+
+#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
+  template<typename _Tp>
+    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
+                                              double>::__type
+    trunc(_Tp __x)
+    { return __builtin_trunc(__x); }
+#endif
+
+#endif // _GLIBCXX_USE_C99_MATH_TR1
+#endif // C++11
+
+#if __cplusplus >= 201703L
+
+  // [c.math.hypot3], three-dimensional hypotenuse
+#define __cpp_lib_hypot 201603L
+
+  template<typename _Tp>
+    inline _Tp
+    __hypot3(_Tp __x, _Tp __y, _Tp __z)
+    {
+      __x = std::abs(__x);
+      __y = std::abs(__y);
+      __z = std::abs(__z);
+      if (_Tp __a = __x < __y ? __y < __z ? __z : __y : __x < __z ? __z : __x)
+	return __a * std::sqrt((__x / __a) * (__x / __a)
+			       + (__y / __a) * (__y / __a)
+			       + (__z / __a) * (__z / __a));
+      else
+	return {};
+    }
+
+  inline float
+  hypot(float __x, float __y, float __z)
+  { return std::__hypot3<float>(__x, __y, __z); }
+
+  inline double
+  hypot(double __x, double __y, double __z)
+  { return std::__hypot3<double>(__x, __y, __z); }
+
+  inline long double
+  hypot(long double __x, long double __y, long double __z)
+  { return std::__hypot3<long double>(__x, __y, __z); }
+
+  template<typename _Tp, typename _Up, typename _Vp>
+    __gnu_cxx::__promoted_t<_Tp, _Up, _Vp>
+    hypot(_Tp __x, _Up __y, _Vp __z)
+    {
+      using __type = __gnu_cxx::__promoted_t<_Tp, _Up, _Vp>;
+      return std::__hypot3<__type>(__x, __y, __z);
+    }
+#endif // C++17
+
+#if __cplusplus >= 202002L
+  // linear interpolation
+# define __cpp_lib_interpolate 201902L
+
+  template<typename _Fp>
+    constexpr _Fp
+    __lerp(_Fp __a, _Fp __b, _Fp __t) noexcept
+    {
+      if ((__a <= 0 && __b >= 0) || (__a >= 0 && __b <= 0))
+	return __t * __b + (1 - __t) * __a;
+
+      if (__t == 1)
+	return __b;                        // exact
+
+      // Exact at __t=0, monotonic except near __t=1,
+      // bounded, determinate, and consistent:
+      const _Fp __x = __a + __t * (__b - __a);
+      return (__t > 1) == (__b > __a)
+	? (__b < __x ? __x : __b)
+	: (__b > __x ? __x : __b);  // monotonic near __t=1
+    }
+
+  constexpr float
+  lerp(float __a, float __b, float __t) noexcept
+  { return std::__lerp(__a, __b, __t); }
+
+  constexpr double
+  lerp(double __a, double __b, double __t) noexcept
+  { return std::__lerp(__a, __b, __t); }
+
+  constexpr long double
+  lerp(long double __a, long double __b, long double __t) noexcept
+  { return std::__lerp(__a, __b, __t); }
+
+  template<typename _Tp, typename _Up, typename _Vp>
+    constexpr __gnu_cxx::__promoted_t<_Tp, _Up, _Vp>
+    lerp(_Tp __x, _Up __y, _Vp __z) noexcept
+    {
+      using __type = __gnu_cxx::__promoted_t<_Tp, _Up, _Vp>;
+      return std::__lerp<__type>(__x, __y, __z);
+    }
+#endif // C++20
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#if _GLIBCXX_USE_STD_SPEC_FUNCS
+#  include <bits/specfun.h>
+#endif
+
+} // extern "C++"
+
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@cmath.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@cmath.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@codecvt b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@codecvt
new file mode 100644
index 0000000000000000000000000000000000000000..e5b9207379f417d74e4f3fa2bc1f1b73f2317e10
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@codecvt
@@ -0,0 +1,177 @@
+// <codecvt> -*- C++ -*-
+
+// Copyright (C) 2015-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+// ISO C++ 14882: 22.5  Standard code conversion facets
+
+/** @file include/codecvt
+ *  This is a Standard C++ Library header.
+ */
+
+#ifndef _GLIBCXX_CODECVT
+#define _GLIBCXX_CODECVT 1
+
+#pragma GCC system_header
+
+#if __cplusplus < 201103L
+# include <bits/c++0x_warning.h>
+#else
+
+#include <bits/locale_classes.h>
+#include <bits/codecvt.h>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  enum codecvt_mode
+  {
+    consume_header = 4,
+    generate_header = 2,
+    little_endian = 1
+  };
+
+  template<typename _Elem, unsigned long _Maxcode = 0x10ffff,
+	   codecvt_mode _Mode = (codecvt_mode)0>
+    class codecvt_utf8 : public codecvt<_Elem, char, mbstate_t>
+    {
+    public:
+      explicit
+      codecvt_utf8(size_t __refs = 0);
+
+      ~codecvt_utf8();
+    };
+
+  template<typename _Elem, unsigned long _Maxcode = 0x10ffff,
+	   codecvt_mode _Mode = (codecvt_mode)0>
+    class codecvt_utf16 : public codecvt<_Elem, char, mbstate_t>
+    {
+    public:
+      explicit
+      codecvt_utf16(size_t __refs = 0);
+
+      ~codecvt_utf16();
+    };
+
+  template<typename _Elem, unsigned long _Maxcode = 0x10ffff,
+	   codecvt_mode _Mode = (codecvt_mode)0>
+    class codecvt_utf8_utf16 : public codecvt<_Elem, char, mbstate_t>
+    {
+    public:
+      explicit
+      codecvt_utf8_utf16(size_t __refs = 0);
+
+      ~codecvt_utf8_utf16();
+    };
+
+#define _GLIBCXX_CODECVT_SPECIALIZATION2(_NAME, _ELEM) \
+  template<> \
+    class _NAME<_ELEM> \
+    : public codecvt<_ELEM, char, mbstate_t> \
+    { \
+    public: \
+      typedef _ELEM			intern_type; \
+      typedef char			extern_type; \
+      typedef mbstate_t			state_type; \
+ \
+    protected: \
+      _NAME(unsigned long __maxcode, codecvt_mode __mode, size_t __refs) \
+      : codecvt(__refs), _M_maxcode(__maxcode), _M_mode(__mode) { } \
+ \
+      virtual \
+      ~_NAME(); \
+ \
+      virtual result \
+      do_out(state_type& __state, const intern_type* __from, \
+	     const intern_type* __from_end, const intern_type*& __from_next, \
+	     extern_type* __to, extern_type* __to_end, \
+	     extern_type*& __to_next) const; \
+ \
+      virtual result \
+      do_unshift(state_type& __state, \
+		 extern_type* __to, extern_type* __to_end, \
+		 extern_type*& __to_next) const; \
+ \
+      virtual result \
+      do_in(state_type& __state, \
+	     const extern_type* __from, const extern_type* __from_end, \
+	     const extern_type*& __from_next, \
+	     intern_type* __to, intern_type* __to_end, \
+	     intern_type*& __to_next) const; \
+ \
+      virtual \
+      int do_encoding() const throw(); \
+ \
+      virtual \
+      bool do_always_noconv() const throw(); \
+ \
+      virtual \
+      int do_length(state_type&, const extern_type* __from, \
+		    const extern_type* __end, size_t __max) const; \
+ \
+      virtual int \
+      do_max_length() const throw(); \
+ \
+    private: \
+      unsigned long	_M_maxcode; \
+      codecvt_mode	_M_mode; \
+    }
+
+#define _GLIBCXX_CODECVT_SPECIALIZATION(_NAME, _ELEM) \
+  _GLIBCXX_CODECVT_SPECIALIZATION2(__ ## _NAME ## _base, _ELEM); \
+  template<unsigned long _Maxcode, codecvt_mode _Mode> \
+    class _NAME<_ELEM, _Maxcode, _Mode> \
+    : public __ ## _NAME ## _base<_ELEM> \
+    { \
+    public: \
+      explicit \
+      _NAME(size_t __refs = 0) \
+      : __ ## _NAME ## _base<_ELEM>(std::min(_Maxcode, 0x10fffful), \
+				    _Mode, __refs) \
+      { } \
+    }
+
+  template<typename _Elem> class __codecvt_utf8_base;
+  template<typename _Elem> class __codecvt_utf16_base;
+  template<typename _Elem> class __codecvt_utf8_utf16_base;
+
+  _GLIBCXX_CODECVT_SPECIALIZATION(codecvt_utf8, char16_t);
+  _GLIBCXX_CODECVT_SPECIALIZATION(codecvt_utf16, char16_t);
+  _GLIBCXX_CODECVT_SPECIALIZATION(codecvt_utf8_utf16, char16_t);
+
+  _GLIBCXX_CODECVT_SPECIALIZATION(codecvt_utf8, char32_t);
+  _GLIBCXX_CODECVT_SPECIALIZATION(codecvt_utf16, char32_t);
+  _GLIBCXX_CODECVT_SPECIALIZATION(codecvt_utf8_utf16, char32_t);
+
+#ifdef _GLIBCXX_USE_WCHAR_T
+  _GLIBCXX_CODECVT_SPECIALIZATION(codecvt_utf8, wchar_t);
+  _GLIBCXX_CODECVT_SPECIALIZATION(codecvt_utf16, wchar_t);
+  _GLIBCXX_CODECVT_SPECIALIZATION(codecvt_utf8_utf16, wchar_t);
+#endif
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif // C++11
+
+#endif /* _GLIBCXX_CODECVT */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@codecvt.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@codecvt.blob
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Binary files /dev/null and b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@codecvt.blob differ
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@compare b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@compare
new file mode 100644
index 0000000000000000000000000000000000000000..e9cf9139deff6855e0b2c70e49f12b632855f27d
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@compare
@@ -0,0 +1,1246 @@
+// -*- C++ -*- operator<=> three-way comparison support.
+
+// Copyright (C) 2019-2022 Free Software Foundation, Inc.
+//
+// This file is part of GCC.
+//
+// GCC is free software; you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation; either version 3, or (at your option)
+// any later version.
+//
+// GCC is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file compare
+ *  This is a Standard C++ Library header.
+ */
+
+#ifndef _COMPARE
+#define _COMPARE
+
+#pragma GCC system_header
+
+#if __cplusplus > 201703L && __cpp_impl_three_way_comparison >= 201907L
+
+#pragma GCC visibility push(default)
+
+#include <concepts>
+
+#if __cpp_lib_concepts
+# define __cpp_lib_three_way_comparison 201907L
+#endif
+
+namespace std
+{
+  // [cmp.categories], comparison category types
+
+  namespace __cmp_cat
+  {
+    using type = signed char;
+
+    enum class _Ord : type { equivalent = 0, less = -1, greater = 1 };
+
+    enum class _Ncmp : type { _Unordered = 2 };
+
+    struct __unspec
+    {
+      constexpr __unspec(__unspec*) noexcept { }
+    };
+  }
+
+  class partial_ordering
+  {
+    // less=0xff, equiv=0x00, greater=0x01, unordered=0x02
+    __cmp_cat::type _M_value;
+
+    constexpr explicit
+    partial_ordering(__cmp_cat::_Ord __v) noexcept
+    : _M_value(__cmp_cat::type(__v))
+    { }
+
+    constexpr explicit
+    partial_ordering(__cmp_cat::_Ncmp __v) noexcept
+    : _M_value(__cmp_cat::type(__v))
+    { }
+
+    friend class weak_ordering;
+    friend class strong_ordering;
+
+  public:
+    // valid values
+    static const partial_ordering less;
+    static const partial_ordering equivalent;
+    static const partial_ordering greater;
+    static const partial_ordering unordered;
+
+    // comparisons
+    [[nodiscard]]
+    friend constexpr bool
+    operator==(partial_ordering __v, __cmp_cat::__unspec) noexcept
+    { return __v._M_value == 0; }
+
+    [[nodiscard]]
+    friend constexpr bool
+    operator==(partial_ordering, partial_ordering) noexcept = default;
+
+    [[nodiscard]]
+    friend constexpr bool
+    operator< (partial_ordering __v, __cmp_cat::__unspec) noexcept
+    { return __v._M_value == -1; }
+
+    [[nodiscard]]
+    friend constexpr bool
+    operator> (partial_ordering __v, __cmp_cat::__unspec) noexcept
+    { return __v._M_value == 1; }
+
+    [[nodiscard]]
+    friend constexpr bool
+    operator<=(partial_ordering __v, __cmp_cat::__unspec) noexcept
+    { return __v._M_value <= 0; }
+
+    [[nodiscard]]
+    friend constexpr bool
+    operator>=(partial_ordering __v, __cmp_cat::__unspec) noexcept
+    { return __cmp_cat::type(__v._M_value & 1) == __v._M_value; }
+
+    [[nodiscard]]
+    friend constexpr bool
+    operator< (__cmp_cat::__unspec, partial_ordering __v) noexcept
+    { return __v._M_value == 1; }
+
+    [[nodiscard]]
+    friend constexpr bool
+    operator> (__cmp_cat::__unspec, partial_ordering __v) noexcept
+    { return __v._M_value == -1; }
+
+    [[nodiscard]]
+    friend constexpr bool
+    operator<=(__cmp_cat::__unspec, partial_ordering __v) noexcept
+    { return __cmp_cat::type(__v._M_value & 1) == __v._M_value; }
+
+    [[nodiscard]]
+    friend constexpr bool
+    operator>=(__cmp_cat::__unspec, partial_ordering __v) noexcept
+    { return 0 >= __v._M_value; }
+
+    [[nodiscard]]
+    friend constexpr partial_ordering
+    operator<=>(partial_ordering __v, __cmp_cat::__unspec) noexcept
+    { return __v; }
+
+    [[nodiscard]]
+    friend constexpr partial_ordering
+    operator<=>(__cmp_cat::__unspec, partial_ordering __v) noexcept
+    {
+      if (__v._M_value & 1)
+	return partial_ordering(__cmp_cat::_Ord(-__v._M_value));
+      else
+	return __v;
+    }
+  };
+
+  // valid values' definitions
+  inline constexpr partial_ordering
+  partial_ordering::less(__cmp_cat::_Ord::less);
+
+  inline constexpr partial_ordering
+  partial_ordering::equivalent(__cmp_cat::_Ord::equivalent);
+
+  inline constexpr partial_ordering
+  partial_ordering::greater(__cmp_cat::_Ord::greater);
+
+  inline constexpr partial_ordering
+  partial_ordering::unordered(__cmp_cat::_Ncmp::_Unordered);
+
+  class weak_ordering
+  {
+    __cmp_cat::type _M_value;
+
+    constexpr explicit
+    weak_ordering(__cmp_cat::_Ord __v) noexcept : _M_value(__cmp_cat::type(__v))
+    { }
+
+    friend class strong_ordering;
+
+  public:
+    // valid values
+    static const weak_ordering less;
+    static const weak_ordering equivalent;
+    static const weak_ordering greater;
+
+    [[nodiscard]]
+    constexpr operator partial_ordering() const noexcept
+    { return partial_ordering(__cmp_cat::_Ord(_M_value)); }
+
+    // comparisons
+    [[nodiscard]]
+    friend constexpr bool
+    operator==(weak_ordering __v, __cmp_cat::__unspec) noexcept
+    { return __v._M_value == 0; }
+
+    [[nodiscard]]
+    friend constexpr bool
+    operator==(weak_ordering, weak_ordering) noexcept = default;
+
+    [[nodiscard]]
+    friend constexpr bool
+    operator< (weak_ordering __v, __cmp_cat::__unspec) noexcept
+    { return __v._M_value < 0; }
+
+    [[nodiscard]]
+    friend constexpr bool
+    operator> (weak_ordering __v, __cmp_cat::__unspec) noexcept
+    { return __v._M_value > 0; }
+
+    [[nodiscard]]
+    friend constexpr bool
+    operator<=(weak_ordering __v, __cmp_cat::__unspec) noexcept
+    { return __v._M_value <= 0; }
+
+    [[nodiscard]]
+    friend constexpr bool
+    operator>=(weak_ordering __v, __cmp_cat::__unspec) noexcept
+    { return __v._M_value >= 0; }
+
+    [[nodiscard]]
+    friend constexpr bool
+    operator< (__cmp_cat::__unspec, weak_ordering __v) noexcept
+    { return 0 < __v._M_value; }
+
+    [[nodiscard]]
+    friend constexpr bool
+    operator> (__cmp_cat::__unspec, weak_ordering __v) noexcept
+    { return 0 > __v._M_value; }
+
+    [[nodiscard]]
+    friend constexpr bool
+    operator<=(__cmp_cat::__unspec, weak_ordering __v) noexcept
+    { return 0 <= __v._M_value; }
+
+    [[nodiscard]]
+    friend constexpr bool
+    operator>=(__cmp_cat::__unspec, weak_ordering __v) noexcept
+    { return 0 >= __v._M_value; }
+
+    [[nodiscard]]
+    friend constexpr weak_ordering
+    operator<=>(weak_ordering __v, __cmp_cat::__unspec) noexcept
+    { return __v; }
+
+    [[nodiscard]]
+    friend constexpr weak_ordering
+    operator<=>(__cmp_cat::__unspec, weak_ordering __v) noexcept
+    { return weak_ordering(__cmp_cat::_Ord(-__v._M_value)); }
+  };
+
+  // valid values' definitions
+  inline constexpr weak_ordering
+  weak_ordering::less(__cmp_cat::_Ord::less);
+
+  inline constexpr weak_ordering
+  weak_ordering::equivalent(__cmp_cat::_Ord::equivalent);
+
+  inline constexpr weak_ordering
+  weak_ordering::greater(__cmp_cat::_Ord::greater);
+
+  class strong_ordering
+  {
+    __cmp_cat::type _M_value;
+
+    constexpr explicit
+    strong_ordering(__cmp_cat::_Ord __v) noexcept
+    : _M_value(__cmp_cat::type(__v))
+    { }
+
+  public:
+    // valid values
+    static const strong_ordering less;
+    static const strong_ordering equal;
+    static const strong_ordering equivalent;
+    static const strong_ordering greater;
+
+    [[nodiscard]]
+    constexpr operator partial_ordering() const noexcept
+    { return partial_ordering(__cmp_cat::_Ord(_M_value)); }
+
+    [[nodiscard]]
+    constexpr operator weak_ordering() const noexcept
+    { return weak_ordering(__cmp_cat::_Ord(_M_value)); }
+
+    // comparisons
+    [[nodiscard]]
+    friend constexpr bool
+    operator==(strong_ordering __v, __cmp_cat::__unspec) noexcept
+    { return __v._M_value == 0; }
+
+    [[nodiscard]]
+    friend constexpr bool
+    operator==(strong_ordering, strong_ordering) noexcept = default;
+
+    [[nodiscard]]
+    friend constexpr bool
+    operator< (strong_ordering __v, __cmp_cat::__unspec) noexcept
+    { return __v._M_value < 0; }
+
+    [[nodiscard]]
+    friend constexpr bool
+    operator> (strong_ordering __v, __cmp_cat::__unspec) noexcept
+    { return __v._M_value > 0; }
+
+    [[nodiscard]]
+    friend constexpr bool
+    operator<=(strong_ordering __v, __cmp_cat::__unspec) noexcept
+    { return __v._M_value <= 0; }
+
+    [[nodiscard]]
+    friend constexpr bool
+    operator>=(strong_ordering __v, __cmp_cat::__unspec) noexcept
+    { return __v._M_value >= 0; }
+
+    [[nodiscard]]
+    friend constexpr bool
+    operator< (__cmp_cat::__unspec, strong_ordering __v) noexcept
+    { return 0 < __v._M_value; }
+
+    [[nodiscard]]
+    friend constexpr bool
+    operator> (__cmp_cat::__unspec, strong_ordering __v) noexcept
+    { return 0 > __v._M_value; }
+
+    [[nodiscard]]
+    friend constexpr bool
+    operator<=(__cmp_cat::__unspec, strong_ordering __v) noexcept
+    { return 0 <= __v._M_value; }
+
+    [[nodiscard]]
+    friend constexpr bool
+    operator>=(__cmp_cat::__unspec, strong_ordering __v) noexcept
+    { return 0 >= __v._M_value; }
+
+    [[nodiscard]]
+    friend constexpr strong_ordering
+    operator<=>(strong_ordering __v, __cmp_cat::__unspec) noexcept
+    { return __v; }
+
+    [[nodiscard]]
+    friend constexpr strong_ordering
+    operator<=>(__cmp_cat::__unspec, strong_ordering __v) noexcept
+    { return strong_ordering(__cmp_cat::_Ord(-__v._M_value)); }
+  };
+
+  // valid values' definitions
+  inline constexpr strong_ordering
+  strong_ordering::less(__cmp_cat::_Ord::less);
+
+  inline constexpr strong_ordering
+  strong_ordering::equal(__cmp_cat::_Ord::equivalent);
+
+  inline constexpr strong_ordering
+  strong_ordering::equivalent(__cmp_cat::_Ord::equivalent);
+
+  inline constexpr strong_ordering
+  strong_ordering::greater(__cmp_cat::_Ord::greater);
+
+
+  // named comparison functions
+  [[nodiscard]]
+  constexpr bool
+  is_eq(partial_ordering __cmp) noexcept
+  { return __cmp == 0; }
+
+  [[nodiscard]]
+  constexpr bool
+  is_neq(partial_ordering __cmp) noexcept
+  { return __cmp != 0; }
+
+  [[nodiscard]]
+  constexpr bool
+  is_lt  (partial_ordering __cmp) noexcept
+  { return __cmp < 0; }
+
+  [[nodiscard]]
+  constexpr bool
+  is_lteq(partial_ordering __cmp) noexcept
+  { return __cmp <= 0; }
+
+  [[nodiscard]]
+  constexpr bool
+  is_gt  (partial_ordering __cmp) noexcept
+  { return __cmp > 0; }
+
+  [[nodiscard]]
+  constexpr bool
+  is_gteq(partial_ordering __cmp) noexcept
+  { return __cmp >= 0; }
+
+  namespace __detail
+  {
+    template<typename _Tp>
+      inline constexpr unsigned __cmp_cat_id = 1;
+    template<>
+      inline constexpr unsigned __cmp_cat_id<partial_ordering> = 2;
+    template<>
+      inline constexpr unsigned __cmp_cat_id<weak_ordering> = 4;
+    template<>
+      inline constexpr unsigned __cmp_cat_id<strong_ordering> = 8;
+
+    template<typename... _Ts>
+      constexpr auto __common_cmp_cat()
+      {
+	constexpr unsigned __cats = (__cmp_cat_id<_Ts> | ...);
+	// If any Ti is not a comparison category type, U is void.
+	if constexpr (__cats & 1)
+	  return;
+	// Otherwise, if at least one Ti is std::partial_ordering,
+	// U is std::partial_ordering.
+	else if constexpr (bool(__cats & __cmp_cat_id<partial_ordering>))
+	  return partial_ordering::equivalent;
+	// Otherwise, if at least one Ti is std::weak_ordering,
+	// U is std::weak_ordering.
+	else if constexpr (bool(__cats & __cmp_cat_id<weak_ordering>))
+	  return weak_ordering::equivalent;
+	// Otherwise, U is std::strong_ordering.
+	else
+	  return strong_ordering::equivalent;
+      }
+  } // namespace __detail
+
+  // [cmp.common], common comparison category type
+  template<typename... _Ts>
+    struct common_comparison_category
+    {
+      using type = decltype(__detail::__common_cmp_cat<_Ts...>());
+    };
+
+  // Partial specializations for one and zero argument cases.
+
+  template<typename _Tp>
+    struct common_comparison_category<_Tp>
+    { using type = void; };
+
+  template<>
+    struct common_comparison_category<partial_ordering>
+    { using type = partial_ordering; };
+
+  template<>
+    struct common_comparison_category<weak_ordering>
+    { using type = weak_ordering; };
+
+  template<>
+    struct common_comparison_category<strong_ordering>
+    { using type = strong_ordering; };
+
+  template<>
+    struct common_comparison_category<>
+    { using type = strong_ordering; };
+
+  template<typename... _Ts>
+    using common_comparison_category_t
+      = typename common_comparison_category<_Ts...>::type;
+
+#if __cpp_lib_concepts
+  namespace __detail
+  {
+    template<typename _Tp, typename _Cat>
+      concept __compares_as
+	= same_as<common_comparison_category_t<_Tp, _Cat>, _Cat>;
+  } // namespace __detail
+
+  // [cmp.concept], concept three_way_comparable
+  template<typename _Tp, typename _Cat = partial_ordering>
+    concept three_way_comparable
+      = __detail::__weakly_eq_cmp_with<_Tp, _Tp>
+      && __detail::__partially_ordered_with<_Tp, _Tp>
+      && requires(const remove_reference_t<_Tp>& __a,
+		  const remove_reference_t<_Tp>& __b)
+      {
+	{ __a <=> __b } -> __detail::__compares_as<_Cat>;
+      };
+
+  template<typename _Tp, typename _Up, typename _Cat = partial_ordering>
+    concept three_way_comparable_with
+      = three_way_comparable<_Tp, _Cat>
+      && three_way_comparable<_Up, _Cat>
+      && common_reference_with<const remove_reference_t<_Tp>&,
+			       const remove_reference_t<_Up>&>
+      && three_way_comparable<
+	  common_reference_t<const remove_reference_t<_Tp>&,
+			     const remove_reference_t<_Up>&>, _Cat>
+      && __detail::__weakly_eq_cmp_with<_Tp, _Up>
+      && __detail::__partially_ordered_with<_Tp, _Up>
+      && requires(const remove_reference_t<_Tp>& __t,
+		  const remove_reference_t<_Up>& __u)
+      {
+	{ __t <=> __u } -> __detail::__compares_as<_Cat>;
+	{ __u <=> __t } -> __detail::__compares_as<_Cat>;
+      };
+
+  namespace __detail
+  {
+    template<typename _Tp, typename _Up>
+      using __cmp3way_res_t
+	= decltype(std::declval<_Tp>() <=> std::declval<_Up>());
+
+    // Implementation of std::compare_three_way_result.
+    // It is undefined for a program to add specializations of
+    // std::compare_three_way_result, so the std::compare_three_way_result_t
+    // alias ignores std::compare_three_way_result and uses
+    // __detail::__cmp3way_res_impl directly instead.
+    template<typename _Tp, typename _Up>
+      struct __cmp3way_res_impl
+      { };
+
+    template<typename _Tp, typename _Up>
+      requires requires { typename __cmp3way_res_t<__cref<_Tp>, __cref<_Up>>; }
+      struct __cmp3way_res_impl<_Tp, _Up>
+      {
+	using type = __cmp3way_res_t<__cref<_Tp>, __cref<_Up>>;
+      };
+  } // namespace __detail
+
+  /// [cmp.result], result of three-way comparison
+  template<typename _Tp, typename _Up = _Tp>
+    struct compare_three_way_result
+    : __detail::__cmp3way_res_impl<_Tp, _Up>
+    { };
+
+  /// [cmp.result], result of three-way comparison
+  template<typename _Tp, typename _Up = _Tp>
+    using compare_three_way_result_t
+      = typename __detail::__cmp3way_res_impl<_Tp, _Up>::type;
+
+  namespace __detail
+  {
+    // BUILTIN-PTR-THREE-WAY(T, U)
+    // This determines whether t <=> u results in a call to a built-in
+    // operator<=> comparing pointers. It doesn't work for function pointers
+    // (PR 93628).
+    template<typename _Tp, typename _Up>
+      concept __3way_builtin_ptr_cmp
+	= requires(_Tp&& __t, _Up&& __u)
+	  { static_cast<_Tp&&>(__t) <=> static_cast<_Up&&>(__u); }
+	  && convertible_to<_Tp, const volatile void*>
+	  && convertible_to<_Up, const volatile void*>
+	  && ! requires(_Tp&& __t, _Up&& __u)
+	  { operator<=>(static_cast<_Tp&&>(__t), static_cast<_Up&&>(__u)); }
+	  && ! requires(_Tp&& __t, _Up&& __u)
+	  { static_cast<_Tp&&>(__t).operator<=>(static_cast<_Up&&>(__u)); };
+  } // namespace __detail
+
+  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+  // 3530 BUILTIN-PTR-MEOW should not opt the type out of syntactic checks
+
+  // [cmp.object], typename compare_three_way
+  struct compare_three_way
+  {
+    template<typename _Tp, typename _Up>
+      requires three_way_comparable_with<_Tp, _Up>
+      constexpr auto
+      operator() [[nodiscard]] (_Tp&& __t, _Up&& __u) const
+      noexcept(noexcept(std::declval<_Tp>() <=> std::declval<_Up>()))
+      {
+	if constexpr (__detail::__3way_builtin_ptr_cmp<_Tp, _Up>)
+	  {
+	    auto __pt = static_cast<const volatile void*>(__t);
+	    auto __pu = static_cast<const volatile void*>(__u);
+	    if (std::__is_constant_evaluated())
+	      return __pt <=> __pu;
+	    auto __it = reinterpret_cast<__UINTPTR_TYPE__>(__pt);
+	    auto __iu = reinterpret_cast<__UINTPTR_TYPE__>(__pu);
+	    return __it <=> __iu;
+	  }
+	else
+	  return static_cast<_Tp&&>(__t) <=> static_cast<_Up&&>(__u);
+      }
+
+    using is_transparent = void;
+  };
+
+  namespace __cmp_cust
+  {
+    template<floating_point _Tp>
+      constexpr weak_ordering
+      __fp_weak_ordering(_Tp __e, _Tp __f)
+      {
+	// Returns an integer with the same sign as the argument, and magnitude
+	// indicating the classification: zero=1 subnorm=2 norm=3 inf=4 nan=5
+	auto __cat = [](_Tp __fp) -> int {
+	  const int __sign = __builtin_signbit(__fp) ? -1 : 1;
+	  if (__builtin_isnormal(__fp))
+	    return (__fp == 0 ? 1 : 3) * __sign;
+	  if (__builtin_isnan(__fp))
+	    return 5 * __sign;
+	  if (int __inf = __builtin_isinf_sign(__fp))
+	    return 4 * __inf;
+	  return 2 * __sign;
+	};
+
+	auto __po = __e <=> __f;
+	if (is_lt(__po))
+	  return weak_ordering::less;
+	else if (is_gt(__po))
+	  return weak_ordering::greater;
+	else if (__po == partial_ordering::equivalent)
+	  return weak_ordering::equivalent;
+	else  // unordered, at least one argument is NaN
+	  {
+	    // return -1 for negative nan, +1 for positive nan, 0 otherwise.
+	    auto __isnan_sign = [](_Tp __fp) -> int {
+	      return __builtin_isnan(__fp)
+		? __builtin_signbit(__fp) ? -1 : 1
+		: 0;
+	    };
+	    auto __ord = __isnan_sign(__e) <=> __isnan_sign(__f);
+	    if (is_eq(__ord))
+	      return weak_ordering::equivalent;
+	    else if (is_lt(__ord))
+	      return weak_ordering::less;
+	    else
+	      return weak_ordering::greater;
+	  }
+      }
+
+    template<typename _Tp, typename _Up>
+      concept __adl_strong = requires(_Tp&& __t, _Up&& __u)
+	{
+	  strong_ordering(strong_order(static_cast<_Tp&&>(__t),
+				       static_cast<_Up&&>(__u)));
+	};
+
+    template<typename _Tp, typename _Up>
+      concept __adl_weak = requires(_Tp&& __t, _Up&& __u)
+	{
+	  weak_ordering(weak_order(static_cast<_Tp&&>(__t),
+				   static_cast<_Up&&>(__u)));
+	};
+
+    template<typename _Tp, typename _Up>
+      concept __adl_partial = requires(_Tp&& __t, _Up&& __u)
+	{
+	  partial_ordering(partial_order(static_cast<_Tp&&>(__t),
+					 static_cast<_Up&&>(__u)));
+	};
+
+    template<typename _Ord, typename _Tp, typename _Up>
+      concept __cmp3way = requires(_Tp&& __t, _Up&& __u, compare_three_way __c)
+	{
+	  _Ord(__c(static_cast<_Tp&&>(__t), static_cast<_Up&&>(__u)));
+	};
+
+    template<typename _Tp, typename _Up>
+      concept __strongly_ordered
+	= __adl_strong<_Tp, _Up>
+	  || floating_point<remove_reference_t<_Tp>>
+	  || __cmp3way<strong_ordering, _Tp, _Up>;
+
+    template<typename _Tp, typename _Up>
+      concept __decayed_same_as = same_as<decay_t<_Tp>, decay_t<_Up>>;
+
+    class _Strong_order
+    {
+      template<typename _Tp, typename _Up>
+	static constexpr bool
+	_S_noexcept()
+	{
+	  if constexpr (floating_point<decay_t<_Tp>>)
+	    return true;
+	  else if constexpr (__adl_strong<_Tp, _Up>)
+	    return noexcept(strong_ordering(strong_order(std::declval<_Tp>(),
+							 std::declval<_Up>())));
+	  else if constexpr (__cmp3way<strong_ordering, _Tp, _Up>)
+	    return noexcept(compare_three_way()(std::declval<_Tp>(),
+						std::declval<_Up>()));
+	}
+
+      friend class _Weak_order;
+      friend class _Strong_fallback;
+
+      // Names for the supported floating-point representations.
+      enum class _Fp_fmt
+      {
+	_Binary16, _Binary32, _Binary64, _Binary128, // IEEE
+	_X86_80bit,  // x86 80-bit extended precision
+	_M68k_80bit, // m68k 80-bit extended precision
+	_Dbldbl, // IBM 128-bit double-double
+	// TODO: _Bfloat16,
+      };
+
+#ifndef __cpp_using_enum
+      // XXX Remove these once 'using enum' support is ubiquitous.
+      static constexpr _Fp_fmt _Binary16 = _Fp_fmt::_Binary16;
+      static constexpr _Fp_fmt _Binary32 = _Fp_fmt::_Binary32;
+      static constexpr _Fp_fmt _Binary64 = _Fp_fmt::_Binary64;
+      static constexpr _Fp_fmt _Binary128 = _Fp_fmt::_Binary128;
+      static constexpr _Fp_fmt _X86_80bit = _Fp_fmt::_X86_80bit;
+      static constexpr _Fp_fmt _M68k_80bit = _Fp_fmt::_M68k_80bit;
+      static constexpr _Fp_fmt _Dbldbl = _Fp_fmt::_Dbldbl;
+#endif
+
+      // Identify the format used by a floating-point type.
+      template<typename _Tp>
+	static consteval _Fp_fmt
+	_S_fp_fmt() noexcept
+	{
+#ifdef __cpp_using_enum
+	  using enum _Fp_fmt;
+#endif
+
+	  // Identify these formats first, then assume anything else is IEEE.
+	  // N.B. ARM __fp16 alternative format can be handled as binary16.
+
+#ifdef __LONG_DOUBLE_IBM128__
+	  if constexpr (__is_same(_Tp, long double))
+	    return _Dbldbl;
+#elif defined __LONG_DOUBLE_IEEE128__ && defined __SIZEOF_IBM128__
+	  if constexpr (__is_same(_Tp, __ibm128))
+	    return _Dbldbl;
+#endif
+
+#if __LDBL_MANT_DIG__ == 64
+	  if constexpr (__is_same(_Tp, long double))
+	    return __LDBL_MIN_EXP__ == -16381 ? _X86_80bit : _M68k_80bit;
+#endif
+#ifdef __SIZEOF_FLOAT80__
+	  if constexpr (__is_same(_Tp, __float80))
+	    return _X86_80bit;
+#endif
+
+	  constexpr int __width = sizeof(_Tp) * __CHAR_BIT__;
+
+	  if constexpr (__width == 16)       // IEEE binary16 (or ARM fp16).
+	    return _Binary16;
+	  else if constexpr (__width == 32)  // IEEE binary32
+	    return _Binary32;
+	  else if constexpr (__width == 64)  // IEEE binary64
+	    return _Binary64;
+	  else if constexpr (__width == 128) // IEEE binary128
+	    return _Binary128;
+	}
+
+      // So we don't need to include <stdint.h> and pollute the namespace.
+      using int64_t = __INT64_TYPE__;
+      using int32_t = __INT32_TYPE__;
+      using int16_t = __INT16_TYPE__;
+      using uint64_t = __UINT64_TYPE__;
+      using uint16_t = __UINT16_TYPE__;
+
+      // Used to unpack floating-point types that do not fit into an integer.
+      template<typename _Tp>
+	struct _Int
+	{
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+	  uint64_t _M_lo;
+	  _Tp _M_hi;
+#else
+	  _Tp _M_hi;
+	  uint64_t _M_lo;
+#endif
+
+	  constexpr explicit
+	  _Int(_Tp __hi, uint64_t __lo) noexcept : _M_hi(__hi)
+	  { _M_lo = __lo; }
+
+	  constexpr explicit
+	  _Int(uint64_t __lo) noexcept : _M_hi(0)
+	  { _M_lo = __lo; }
+
+	  constexpr bool operator==(const _Int&) const = default;
+
+#if defined __hppa__ || (defined __mips__ && !defined __mips_nan2008)
+	  consteval _Int
+	  operator<<(int __n) const noexcept
+	  {
+	    // XXX this assumes n >= 64, which is true for the use below.
+	    return _Int(static_cast<_Tp>(_M_lo << (__n - 64)), 0);
+	  }
+#endif
+
+	  constexpr _Int&
+	  operator^=(const _Int& __rhs) noexcept
+	  {
+	    _M_hi ^= __rhs._M_hi;
+	    _M_lo ^= __rhs._M_lo;
+	    return *this;
+	  }
+
+	  constexpr strong_ordering
+	  operator<=>(const _Int& __rhs) const noexcept
+	  {
+	    strong_ordering __cmp = _M_hi <=> __rhs._M_hi;
+	    if (__cmp != strong_ordering::equal)
+	      return __cmp;
+	    return _M_lo <=> __rhs._M_lo;
+	  }
+	};
+
+      template<typename _Tp>
+	static constexpr _Tp
+	_S_compl(_Tp __t) noexcept
+	{
+	  constexpr int __width = sizeof(_Tp) * __CHAR_BIT__;
+	  // Sign extend to get all ones or all zeros.
+	  make_unsigned_t<_Tp> __sign = __t >> (__width - 1);
+	  // If the sign bit was set, this flips all bits below it.
+	  // This converts ones' complement to two's complement.
+	  return __t ^ (__sign >> 1);
+	}
+
+      // As above but works on both parts of _Int<T>.
+      template<typename _Tp>
+	static constexpr _Int<_Tp>
+	_S_compl(_Int<_Tp> __t) noexcept
+	{
+	  constexpr int __width = sizeof(_Tp) * __CHAR_BIT__;
+	  make_unsigned_t<_Tp> __sign = __t._M_hi >> (__width - 1);
+	  __t._M_hi ^= (__sign >> 1 );
+	  uint64_t __sign64 = (_Tp)__sign;
+	  __t._M_lo ^= __sign64;
+	  return __t;
+	}
+
+      // Bit-cast a floating-point value to an unsigned integer.
+      template<typename _Tp>
+	constexpr static auto
+	_S_fp_bits(_Tp __val) noexcept
+	{
+	  if constexpr (sizeof(_Tp) == sizeof(int64_t))
+	    return __builtin_bit_cast(int64_t, __val);
+	  else if constexpr (sizeof(_Tp) == sizeof(int32_t))
+	    return __builtin_bit_cast(int32_t, __val);
+	  else if constexpr (sizeof(_Tp) == sizeof(int16_t))
+	    return __builtin_bit_cast(int16_t, __val);
+	  else
+	    {
+#ifdef __cpp_using_enum
+	      using enum _Fp_fmt;
+#endif
+	      constexpr auto __fmt = _S_fp_fmt<_Tp>();
+	      if constexpr (__fmt == _X86_80bit || __fmt == _M68k_80bit)
+		{
+		  if constexpr (sizeof(_Tp) == 3 * sizeof(int32_t))
+		    {
+		      auto __ival = __builtin_bit_cast(_Int<int32_t>, __val);
+		      return _Int<int16_t>(__ival._M_hi, __ival._M_lo);
+		    }
+		  else
+		    {
+		      auto __ival = __builtin_bit_cast(_Int<int64_t>, __val);
+		      return _Int<int16_t>(__ival._M_hi, __ival._M_lo);
+		    }
+		}
+	      else if constexpr (sizeof(_Tp) == 2 * sizeof(int64_t))
+		{
+#if __SIZEOF_INT128__
+		  return __builtin_bit_cast(__int128, __val);
+#else
+		  return __builtin_bit_cast(_Int<int64_t>, __val);
+#endif
+		}
+	      else
+		static_assert(sizeof(_Tp) == sizeof(int64_t),
+			      "unsupported floating-point type");
+	    }
+	}
+
+      template<typename _Tp>
+	static constexpr strong_ordering
+	_S_fp_cmp(_Tp __x, _Tp __y) noexcept
+	{
+#ifdef __vax__
+	  if (__builtin_isnan(__x) || __builtin_isnan(__y))
+	    {
+	      int __ix = (bool) __builtin_isnan(__x);
+	      int __iy = (bool) __builtin_isnan(__y);
+	      __ix *= __builtin_signbit(__x) ? -1 : 1;
+	      __iy *= __builtin_signbit(__y) ? -1 : 1;
+	      return __ix <=> __iy;
+	    }
+	  else
+	    return __builtin_bit_cast(strong_ordering, __x <=> __y);
+#endif
+
+	  auto __ix = _S_fp_bits(__x);
+	  auto __iy = _S_fp_bits(__y);
+
+	  if (__ix == __iy)
+	    return strong_ordering::equal; // All bits are equal, we're done.
+
+#ifdef __cpp_using_enum
+	  using enum _Fp_fmt;
+#endif
+	  constexpr auto __fmt = _S_fp_fmt<_Tp>();
+
+	  if constexpr (__fmt == _Dbldbl) // double-double
+	    {
+	      // Unpack the double-double into two parts.
+	      // We never inspect the low double as a double, cast to integer.
+	      struct _Unpacked { double _M_hi; int64_t _M_lo; };
+	      auto __x2 = __builtin_bit_cast(_Unpacked, __x);
+	      auto __y2 = __builtin_bit_cast(_Unpacked, __y);
+
+	      // Compare the high doubles first and use result if unequal.
+	      auto __cmp = _S_fp_cmp(__x2._M_hi, __y2._M_hi);
+	      if (__cmp != strong_ordering::equal)
+		return __cmp;
+
+	      // For NaN the low double is unused, so if the high doubles
+	      // are the same NaN, we don't need to compare the low doubles.
+	      if (__builtin_isnan(__x2._M_hi))
+		return strong_ordering::equal;
+	      // Similarly, if the low doubles are +zero or -zero (which is
+	      // true for all infinities and some other values), we're done.
+	      if (((__x2._M_lo | __y2._M_lo) & 0x7fffffffffffffffULL) == 0)
+		return strong_ordering::equal;
+
+	      // Otherwise, compare the low parts.
+	      return _S_compl(__x2._M_lo) <=> _S_compl(__y2._M_lo);
+	    }
+	  else
+	    {
+	      if constexpr (__fmt == _M68k_80bit)
+		{
+		  // For m68k the MSB of the significand is ignored for the
+		  // greatest exponent, so either 0 or 1 is valid there.
+		  // Set it before comparing, so that we never have 0 there.
+		  constexpr uint16_t __maxexp = 0x7fff;
+		  if ((__ix._M_hi & __maxexp) == __maxexp)
+		    __ix._M_lo |= 1ull << 63;
+		  if ((__iy._M_hi & __maxexp) == __maxexp)
+		    __iy._M_lo |= 1ull << 63;
+		}
+	      else
+		{
+#if defined __hppa__ || (defined __mips__ && !defined __mips_nan2008)
+		  // IEEE 754-1985 allowed the meaning of the quiet/signaling
+		  // bit to be reversed. Flip that to give desired ordering.
+		  if (__builtin_isnan(__x) && __builtin_isnan(__y))
+		    {
+		      using _Int = decltype(__ix);
+
+		      constexpr int __nantype = __fmt == _Binary32  ?  22
+					      : __fmt == _Binary64  ?  51
+					      : __fmt == _Binary128 ? 111
+					      : -1;
+		      constexpr _Int __bit = _Int(1) << __nantype;
+		      __ix ^= __bit;
+		      __iy ^= __bit;
+		    }
+#endif
+		}
+	      return _S_compl(__ix) <=> _S_compl(__iy);
+	    }
+	}
+
+    public:
+      template<typename _Tp, __decayed_same_as<_Tp> _Up>
+	requires __strongly_ordered<_Tp, _Up>
+	constexpr strong_ordering
+	operator() [[nodiscard]] (_Tp&& __e, _Up&& __f) const
+	noexcept(_S_noexcept<_Tp, _Up>())
+	{
+	  if constexpr (floating_point<decay_t<_Tp>>)
+	    return _S_fp_cmp(__e, __f);
+	  else if constexpr (__adl_strong<_Tp, _Up>)
+	    return strong_ordering(strong_order(static_cast<_Tp&&>(__e),
+						static_cast<_Up&&>(__f)));
+	  else if constexpr (__cmp3way<strong_ordering, _Tp, _Up>)
+	    return compare_three_way()(static_cast<_Tp&&>(__e),
+				       static_cast<_Up&&>(__f));
+	}
+    };
+
+    template<typename _Tp, typename _Up>
+      concept __weakly_ordered
+	= floating_point<remove_reference_t<_Tp>>
+	  || __adl_weak<_Tp, _Up>
+	  || __cmp3way<weak_ordering, _Tp, _Up>
+	  || __strongly_ordered<_Tp, _Up>;
+
+    class _Weak_order
+    {
+      template<typename _Tp, typename _Up>
+	static constexpr bool
+	_S_noexcept()
+	{
+	  if constexpr (floating_point<decay_t<_Tp>>)
+	    return true;
+	  else if constexpr (__adl_weak<_Tp, _Up>)
+	    return noexcept(weak_ordering(weak_order(std::declval<_Tp>(),
+						     std::declval<_Up>())));
+	  else if constexpr (__cmp3way<weak_ordering, _Tp, _Up>)
+	    return noexcept(compare_three_way()(std::declval<_Tp>(),
+						std::declval<_Up>()));
+	  else if constexpr (__strongly_ordered<_Tp, _Up>)
+	    return _Strong_order::_S_noexcept<_Tp, _Up>();
+	}
+
+      friend class _Partial_order;
+      friend class _Weak_fallback;
+
+    public:
+      template<typename _Tp, __decayed_same_as<_Tp> _Up>
+	requires __weakly_ordered<_Tp, _Up>
+	constexpr weak_ordering
+	operator() [[nodiscard]] (_Tp&& __e, _Up&& __f) const
+	noexcept(_S_noexcept<_Tp, _Up>())
+	{
+	  if constexpr (floating_point<decay_t<_Tp>>)
+	    return __cmp_cust::__fp_weak_ordering(__e, __f);
+	  else if constexpr (__adl_weak<_Tp, _Up>)
+	    return weak_ordering(weak_order(static_cast<_Tp&&>(__e),
+					    static_cast<_Up&&>(__f)));
+	  else if constexpr (__cmp3way<weak_ordering, _Tp, _Up>)
+	    return compare_three_way()(static_cast<_Tp&&>(__e),
+				       static_cast<_Up&&>(__f));
+	  else if constexpr (__strongly_ordered<_Tp, _Up>)
+	    return _Strong_order{}(static_cast<_Tp&&>(__e),
+				   static_cast<_Up&&>(__f));
+	}
+    };
+
+    template<typename _Tp, typename _Up>
+      concept __partially_ordered
+	= __adl_partial<_Tp, _Up>
+	|| __cmp3way<partial_ordering, _Tp, _Up>
+	|| __weakly_ordered<_Tp, _Up>;
+
+    class _Partial_order
+    {
+      template<typename _Tp, typename _Up>
+	static constexpr bool
+	_S_noexcept()
+	{
+	  if constexpr (__adl_partial<_Tp, _Up>)
+	    return noexcept(partial_ordering(partial_order(std::declval<_Tp>(),
+							 std::declval<_Up>())));
+	  else if constexpr (__cmp3way<partial_ordering, _Tp, _Up>)
+	    return noexcept(compare_three_way()(std::declval<_Tp>(),
+						std::declval<_Up>()));
+	  else if constexpr (__weakly_ordered<_Tp, _Up>)
+	    return _Weak_order::_S_noexcept<_Tp, _Up>();
+	}
+
+      friend class _Partial_fallback;
+
+    public:
+      template<typename _Tp, __decayed_same_as<_Tp> _Up>
+	requires __partially_ordered<_Tp, _Up>
+	constexpr partial_ordering
+	operator() [[nodiscard]] (_Tp&& __e, _Up&& __f) const
+	noexcept(_S_noexcept<_Tp, _Up>())
+	{
+	  if constexpr (__adl_partial<_Tp, _Up>)
+	    return partial_ordering(partial_order(static_cast<_Tp&&>(__e),
+						  static_cast<_Up&&>(__f)));
+	  else if constexpr (__cmp3way<partial_ordering, _Tp, _Up>)
+	    return compare_three_way()(static_cast<_Tp&&>(__e),
+				       static_cast<_Up&&>(__f));
+	  else if constexpr (__weakly_ordered<_Tp, _Up>)
+	    return _Weak_order{}(static_cast<_Tp&&>(__e),
+				 static_cast<_Up&&>(__f));
+	}
+    };
+
+    template<typename _Tp, typename _Up>
+      concept __op_eq_lt = requires(_Tp&& __t, _Up&& __u)
+	{
+	  { static_cast<_Tp&&>(__t) == static_cast<_Up&&>(__u) }
+	    -> convertible_to<bool>;
+	  { static_cast<_Tp&&>(__t) < static_cast<_Up&&>(__u) }
+	    -> convertible_to<bool>;
+	};
+
+    class _Strong_fallback
+    {
+      template<typename _Tp, typename _Up>
+	static constexpr bool
+	_S_noexcept()
+	{
+	  if constexpr (__strongly_ordered<_Tp, _Up>)
+	    return _Strong_order::_S_noexcept<_Tp, _Up>();
+	  else
+	    return noexcept(bool(std::declval<_Tp>() == std::declval<_Up>()))
+	      && noexcept(bool(std::declval<_Tp>() < std::declval<_Up>()));
+	}
+
+    public:
+      template<typename _Tp, __decayed_same_as<_Tp> _Up>
+	requires __strongly_ordered<_Tp, _Up> || __op_eq_lt<_Tp, _Up>
+	constexpr strong_ordering
+	operator() [[nodiscard]] (_Tp&& __e, _Up&& __f) const
+	noexcept(_S_noexcept<_Tp, _Up>())
+	{
+	  if constexpr (__strongly_ordered<_Tp, _Up>)
+	    return _Strong_order{}(static_cast<_Tp&&>(__e),
+				   static_cast<_Up&&>(__f));
+	  else // __op_eq_lt<_Tp, _Up>
+	    return static_cast<_Tp&&>(__e) == static_cast<_Up&&>(__f)
+	      ? strong_ordering::equal
+	      : static_cast<_Tp&&>(__e) < static_cast<_Up&&>(__f)
+	      ? strong_ordering::less
+	      : strong_ordering::greater;
+	}
+    };
+
+    class _Weak_fallback
+    {
+      template<typename _Tp, typename _Up>
+	static constexpr bool
+	_S_noexcept()
+	{
+	  if constexpr (__weakly_ordered<_Tp, _Up>)
+	    return _Weak_order::_S_noexcept<_Tp, _Up>();
+	  else
+	    return noexcept(bool(std::declval<_Tp>() == std::declval<_Up>()))
+	      && noexcept(bool(std::declval<_Tp>() < std::declval<_Up>()));
+	}
+
+    public:
+      template<typename _Tp, __decayed_same_as<_Tp> _Up>
+	requires __weakly_ordered<_Tp, _Up> || __op_eq_lt<_Tp, _Up>
+	constexpr weak_ordering
+	operator() [[nodiscard]] (_Tp&& __e, _Up&& __f) const
+	noexcept(_S_noexcept<_Tp, _Up>())
+	{
+	  if constexpr (__weakly_ordered<_Tp, _Up>)
+	    return _Weak_order{}(static_cast<_Tp&&>(__e),
+				 static_cast<_Up&&>(__f));
+	  else // __op_eq_lt<_Tp, _Up>
+	    return static_cast<_Tp&&>(__e) == static_cast<_Up&&>(__f)
+	      ? weak_ordering::equivalent
+	      : static_cast<_Tp&&>(__e) < static_cast<_Up&&>(__f)
+	      ? weak_ordering::less
+	      : weak_ordering::greater;
+	}
+    };
+
+    // _GLIBCXX_RESOLVE_LIB_DEFECTS
+    // 3465. compare_partial_order_fallback requires F < E
+    template<typename _Tp, typename _Up>
+      concept __op_eq_lt_lt = __op_eq_lt<_Tp, _Up>
+	&& requires(_Tp&& __t, _Up&& __u)
+	{
+	  { static_cast<_Up&&>(__u) < static_cast<_Tp&&>(__t) }
+	    -> convertible_to<bool>;
+	};
+
+    class _Partial_fallback
+    {
+      template<typename _Tp, typename _Up>
+	static constexpr bool
+	_S_noexcept()
+	{
+	  if constexpr (__partially_ordered<_Tp, _Up>)
+	    return _Partial_order::_S_noexcept<_Tp, _Up>();
+	  else
+	    return noexcept(bool(std::declval<_Tp>() == std::declval<_Up>()))
+	      && noexcept(bool(std::declval<_Tp>() < std::declval<_Up>()));
+	}
+
+    public:
+      template<typename _Tp, __decayed_same_as<_Tp> _Up>
+	requires __partially_ordered<_Tp, _Up> || __op_eq_lt_lt<_Tp, _Up>
+	constexpr partial_ordering
+	operator() [[nodiscard]] (_Tp&& __e, _Up&& __f) const
+	noexcept(_S_noexcept<_Tp, _Up>())
+	{
+	  if constexpr (__partially_ordered<_Tp, _Up>)
+	    return _Partial_order{}(static_cast<_Tp&&>(__e),
+				    static_cast<_Up&&>(__f));
+	  else // __op_eq_lt_lt<_Tp, _Up>
+	    return static_cast<_Tp&&>(__e) == static_cast<_Up&&>(__f)
+	      ? partial_ordering::equivalent
+	      : static_cast<_Tp&&>(__e) < static_cast<_Up&&>(__f)
+	      ? partial_ordering::less
+	      : static_cast<_Up&&>(__f) < static_cast<_Tp&&>(__e)
+	      ? partial_ordering::greater
+	      : partial_ordering::unordered;
+	}
+    };
+  } // namespace __cmp_cust
+
+  // [cmp.alg], comparison algorithms
+  inline namespace __cmp_alg
+  {
+    inline constexpr __cmp_cust::_Strong_order strong_order{};
+
+    inline constexpr __cmp_cust::_Weak_order weak_order{};
+
+    inline constexpr __cmp_cust::_Partial_order partial_order{};
+
+    inline constexpr __cmp_cust::_Strong_fallback
+    compare_strong_order_fallback{};
+
+    inline constexpr __cmp_cust::_Weak_fallback
+    compare_weak_order_fallback{};
+
+    inline constexpr __cmp_cust::_Partial_fallback
+    compare_partial_order_fallback{};
+  }
+
+  namespace __detail
+  {
+    // [expos.only.func] synth-three-way
+    inline constexpr struct _Synth3way
+    {
+      template<typename _Tp, typename _Up>
+	static constexpr bool
+	_S_noexcept(const _Tp* __t = nullptr, const _Up* __u = nullptr)
+	{
+	  if constexpr (three_way_comparable_with<_Tp, _Up>)
+	    return noexcept(*__t <=> *__u);
+	  else
+	    return noexcept(*__t < *__u) && noexcept(*__u < *__t);
+	}
+
+      template<typename _Tp, typename _Up>
+	[[nodiscard]]
+	constexpr auto
+	operator()(const _Tp& __t, const _Up& __u) const
+	noexcept(_S_noexcept<_Tp, _Up>())
+	requires requires
+	{
+	  { __t < __u } -> __boolean_testable;
+	  { __u < __t } -> __boolean_testable;
+	}
+	{
+	  if constexpr (three_way_comparable_with<_Tp, _Up>)
+	    return __t <=> __u;
+	  else
+	    {
+	      if (__t < __u)
+		return weak_ordering::less;
+	      else if (__u < __t)
+		return weak_ordering::greater;
+	      else
+		return weak_ordering::equivalent;
+	    }
+	}
+    } __synth3way = {};
+
+    // [expos.only.func] synth-three-way-result
+    template<typename _Tp, typename _Up = _Tp>
+      using __synth3way_t
+	= decltype(__detail::__synth3way(std::declval<_Tp&>(),
+					 std::declval<_Up&>()));
+  } // namespace __detail
+#endif // concepts
+} // namespace std
+
+#pragma GCC visibility pop
+
+#endif // C++20
+
+#endif // _COMPARE
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@compare.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@compare.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@complex b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@complex
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@@ -0,0 +1,1995 @@
+// The template and inlines for the -*- C++ -*- complex number classes.
+
+// Copyright (C) 1997-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file include/complex
+ *  This is a Standard C++ Library header.
+ */
+
+//
+// ISO C++ 14882: 26.2  Complex Numbers
+// Note: this is not a conforming implementation.
+// Initially implemented by Ulrich Drepper <drepper@cygnus.com>
+// Improved by Gabriel Dos Reis <dosreis@cmla.ens-cachan.fr>
+//
+
+#ifndef _GLIBCXX_COMPLEX
+#define _GLIBCXX_COMPLEX 1
+
+#pragma GCC system_header
+
+#include <bits/c++config.h>
+#include <bits/cpp_type_traits.h>
+#include <ext/type_traits.h>
+#include <cmath>
+#include <sstream>
+
+// Get rid of a macro possibly defined in <complex.h>
+#undef complex
+
+#if __cplusplus > 201703L
+# define __cpp_lib_constexpr_complex 201711L
+#endif
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /**
+   * @defgroup complex_numbers Complex Numbers
+   * @ingroup numerics
+   *
+   * Classes and functions for complex numbers.
+   * @{
+   */
+
+  // Forward declarations.
+  template<typename _Tp> class complex;
+  template<> class complex<float>;
+  template<> class complex<double>;
+  template<> class complex<long double>;
+
+  ///  Return magnitude of @a z.
+  template<typename _Tp> _Tp abs(const complex<_Tp>&);
+  ///  Return phase angle of @a z.
+  template<typename _Tp> _Tp arg(const complex<_Tp>&);
+  ///  Return @a z magnitude squared.
+  template<typename _Tp> _Tp _GLIBCXX20_CONSTEXPR norm(const complex<_Tp>&);
+
+  ///  Return complex conjugate of @a z.
+  template<typename _Tp>
+    _GLIBCXX20_CONSTEXPR complex<_Tp> conj(const complex<_Tp>&);
+  ///  Return complex with magnitude @a rho and angle @a theta.
+  template<typename _Tp> complex<_Tp> polar(const _Tp&, const _Tp& = 0);
+
+  // Transcendentals:
+  /// Return complex cosine of @a z.
+  template<typename _Tp> complex<_Tp> cos(const complex<_Tp>&);
+  /// Return complex hyperbolic cosine of @a z.
+  template<typename _Tp> complex<_Tp> cosh(const complex<_Tp>&);
+  /// Return complex base e exponential of @a z.
+  template<typename _Tp> complex<_Tp> exp(const complex<_Tp>&);
+  /// Return complex natural logarithm of @a z.
+  template<typename _Tp> complex<_Tp> log(const complex<_Tp>&);
+  /// Return complex base 10 logarithm of @a z.
+  template<typename _Tp> complex<_Tp> log10(const complex<_Tp>&);
+  /// Return @a x to the @a y'th power.
+  template<typename _Tp> complex<_Tp> pow(const complex<_Tp>&, int);
+  /// Return @a x to the @a y'th power.
+  template<typename _Tp> complex<_Tp> pow(const complex<_Tp>&, const _Tp&);
+  /// Return @a x to the @a y'th power.
+  template<typename _Tp> complex<_Tp> pow(const complex<_Tp>&,
+                                          const complex<_Tp>&);
+  /// Return @a x to the @a y'th power.
+  template<typename _Tp> complex<_Tp> pow(const _Tp&, const complex<_Tp>&);
+  /// Return complex sine of @a z.
+  template<typename _Tp> complex<_Tp> sin(const complex<_Tp>&);
+  /// Return complex hyperbolic sine of @a z.
+  template<typename _Tp> complex<_Tp> sinh(const complex<_Tp>&);
+  /// Return complex square root of @a z.
+  template<typename _Tp> complex<_Tp> sqrt(const complex<_Tp>&);
+  /// Return complex tangent of @a z.
+  template<typename _Tp> complex<_Tp> tan(const complex<_Tp>&);
+  /// Return complex hyperbolic tangent of @a z.
+  template<typename _Tp> complex<_Tp> tanh(const complex<_Tp>&);
+
+
+  // 26.2.2  Primary template class complex
+  /**
+   *  Template to represent complex numbers.
+   *
+   *  Specializations for float, double, and long double are part of the
+   *  library.  Results with any other type are not guaranteed.
+   *
+   *  @param  Tp  Type of real and imaginary values.
+  */
+  template<typename _Tp>
+    class complex
+    {
+    public:
+      /// Value typedef.
+      typedef _Tp value_type;
+
+      ///  Default constructor.  First parameter is x, second parameter is y.
+      ///  Unspecified parameters default to 0.
+      _GLIBCXX_CONSTEXPR complex(const _Tp& __r = _Tp(), const _Tp& __i = _Tp())
+      : _M_real(__r), _M_imag(__i) { }
+
+      // Let the compiler synthesize the copy constructor
+#if __cplusplus >= 201103L
+      constexpr complex(const complex&) = default;
+#endif
+
+      ///  Converting constructor.
+      template<typename _Up>
+        _GLIBCXX_CONSTEXPR complex(const complex<_Up>& __z)
+	: _M_real(__z.real()), _M_imag(__z.imag()) { }
+
+#if __cplusplus >= 201103L
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // DR 387. std::complex over-encapsulated.
+      _GLIBCXX_ABI_TAG_CXX11
+      constexpr _Tp
+      real() const { return _M_real; }
+
+      _GLIBCXX_ABI_TAG_CXX11
+      constexpr _Tp
+      imag() const { return _M_imag; }
+#else
+      ///  Return real part of complex number.
+      _Tp&
+      real() { return _M_real; }
+
+      ///  Return real part of complex number.
+      const _Tp&
+      real() const { return _M_real; }
+
+      ///  Return imaginary part of complex number.
+      _Tp&
+      imag() { return _M_imag; }
+
+      ///  Return imaginary part of complex number.
+      const _Tp&
+      imag() const { return _M_imag; }
+#endif
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // DR 387. std::complex over-encapsulated.
+      _GLIBCXX20_CONSTEXPR void
+      real(_Tp __val) { _M_real = __val; }
+
+      _GLIBCXX20_CONSTEXPR void
+      imag(_Tp __val) { _M_imag = __val; }
+
+      /// Assign a scalar to this complex number.
+      _GLIBCXX20_CONSTEXPR complex<_Tp>& operator=(const _Tp&);
+
+      /// Add a scalar to this complex number.
+      // 26.2.5/1
+      _GLIBCXX20_CONSTEXPR complex<_Tp>&
+      operator+=(const _Tp& __t)
+      {
+	_M_real += __t;
+	return *this;
+      }
+
+      /// Subtract a scalar from this complex number.
+      // 26.2.5/3
+      _GLIBCXX20_CONSTEXPR complex<_Tp>&
+      operator-=(const _Tp& __t)
+      {
+	_M_real -= __t;
+	return *this;
+      }
+
+      /// Multiply this complex number by a scalar.
+      _GLIBCXX20_CONSTEXPR complex<_Tp>& operator*=(const _Tp&);
+      /// Divide this complex number by a scalar.
+      _GLIBCXX20_CONSTEXPR complex<_Tp>& operator/=(const _Tp&);
+
+      // Let the compiler synthesize the copy assignment operator
+#if __cplusplus >= 201103L
+      _GLIBCXX20_CONSTEXPR complex& operator=(const complex&) = default;
+#endif
+
+      /// Assign another complex number to this one.
+      template<typename _Up>
+        _GLIBCXX20_CONSTEXPR complex<_Tp>& operator=(const complex<_Up>&);
+      /// Add another complex number to this one.
+      template<typename _Up>
+        _GLIBCXX20_CONSTEXPR complex<_Tp>& operator+=(const complex<_Up>&);
+      /// Subtract another complex number from this one.
+      template<typename _Up>
+        _GLIBCXX20_CONSTEXPR complex<_Tp>& operator-=(const complex<_Up>&);
+      /// Multiply this complex number by another.
+      template<typename _Up>
+        _GLIBCXX20_CONSTEXPR complex<_Tp>& operator*=(const complex<_Up>&);
+      /// Divide this complex number by another.
+      template<typename _Up>
+        _GLIBCXX20_CONSTEXPR complex<_Tp>& operator/=(const complex<_Up>&);
+
+      _GLIBCXX_CONSTEXPR complex __rep() const
+      { return *this; }
+
+    private:
+      _Tp _M_real;
+      _Tp _M_imag;
+    };
+
+  template<typename _Tp>
+    _GLIBCXX20_CONSTEXPR complex<_Tp>&
+    complex<_Tp>::operator=(const _Tp& __t)
+    {
+     _M_real = __t;
+     _M_imag = _Tp();
+     return *this;
+    }
+
+  // 26.2.5/5
+  template<typename _Tp>
+    _GLIBCXX20_CONSTEXPR complex<_Tp>&
+    complex<_Tp>::operator*=(const _Tp& __t)
+    {
+      _M_real *= __t;
+      _M_imag *= __t;
+      return *this;
+    }
+
+  // 26.2.5/7
+  template<typename _Tp>
+    _GLIBCXX20_CONSTEXPR complex<_Tp>&
+    complex<_Tp>::operator/=(const _Tp& __t)
+    {
+      _M_real /= __t;
+      _M_imag /= __t;
+      return *this;
+    }
+
+  template<typename _Tp>
+    template<typename _Up>
+    _GLIBCXX20_CONSTEXPR complex<_Tp>&
+    complex<_Tp>::operator=(const complex<_Up>& __z)
+    {
+      _M_real = __z.real();
+      _M_imag = __z.imag();
+      return *this;
+    }
+
+  // 26.2.5/9
+  template<typename _Tp>
+    template<typename _Up>
+    _GLIBCXX20_CONSTEXPR complex<_Tp>&
+    complex<_Tp>::operator+=(const complex<_Up>& __z)
+    {
+      _M_real += __z.real();
+      _M_imag += __z.imag();
+      return *this;
+    }
+
+  // 26.2.5/11
+  template<typename _Tp>
+    template<typename _Up>
+    _GLIBCXX20_CONSTEXPR complex<_Tp>&
+    complex<_Tp>::operator-=(const complex<_Up>& __z)
+    {
+      _M_real -= __z.real();
+      _M_imag -= __z.imag();
+      return *this;
+    }
+
+  // 26.2.5/13
+  // XXX: This is a grammar school implementation.
+  template<typename _Tp>
+    template<typename _Up>
+    _GLIBCXX20_CONSTEXPR complex<_Tp>&
+    complex<_Tp>::operator*=(const complex<_Up>& __z)
+    {
+      const _Tp __r = _M_real * __z.real() - _M_imag * __z.imag();
+      _M_imag = _M_real * __z.imag() + _M_imag * __z.real();
+      _M_real = __r;
+      return *this;
+    }
+
+  // 26.2.5/15
+  // XXX: This is a grammar school implementation.
+  template<typename _Tp>
+    template<typename _Up>
+    _GLIBCXX20_CONSTEXPR complex<_Tp>&
+    complex<_Tp>::operator/=(const complex<_Up>& __z)
+    {
+      const _Tp __r =  _M_real * __z.real() + _M_imag * __z.imag();
+      const _Tp __n = std::norm(__z);
+      _M_imag = (_M_imag * __z.real() - _M_real * __z.imag()) / __n;
+      _M_real = __r / __n;
+      return *this;
+    }
+
+  // Operators:
+  ///@{
+  ///  Return new complex value @a x plus @a y.
+  template<typename _Tp>
+    inline _GLIBCXX20_CONSTEXPR complex<_Tp>
+    operator+(const complex<_Tp>& __x, const complex<_Tp>& __y)
+    {
+      complex<_Tp> __r = __x;
+      __r += __y;
+      return __r;
+    }
+
+  template<typename _Tp>
+    inline _GLIBCXX20_CONSTEXPR complex<_Tp>
+    operator+(const complex<_Tp>& __x, const _Tp& __y)
+    {
+      complex<_Tp> __r = __x;
+      __r += __y;
+      return __r;
+    }
+
+  template<typename _Tp>
+    inline _GLIBCXX20_CONSTEXPR complex<_Tp>
+    operator+(const _Tp& __x, const complex<_Tp>& __y)
+    {
+      complex<_Tp> __r = __y;
+      __r += __x;
+      return __r;
+    }
+  ///@}
+
+  ///@{
+  ///  Return new complex value @a x minus @a y.
+  template<typename _Tp>
+    inline _GLIBCXX20_CONSTEXPR complex<_Tp>
+    operator-(const complex<_Tp>& __x, const complex<_Tp>& __y)
+    {
+      complex<_Tp> __r = __x;
+      __r -= __y;
+      return __r;
+    }
+
+  template<typename _Tp>
+    inline _GLIBCXX20_CONSTEXPR complex<_Tp>
+    operator-(const complex<_Tp>& __x, const _Tp& __y)
+    {
+      complex<_Tp> __r = __x;
+      __r -= __y;
+      return __r;
+    }
+
+  template<typename _Tp>
+    inline _GLIBCXX20_CONSTEXPR complex<_Tp>
+    operator-(const _Tp& __x, const complex<_Tp>& __y)
+    {
+      complex<_Tp> __r = -__y;
+      __r += __x;
+      return __r;
+    }
+  ///@}
+
+  ///@{
+  ///  Return new complex value @a x times @a y.
+  template<typename _Tp>
+    inline _GLIBCXX20_CONSTEXPR complex<_Tp>
+    operator*(const complex<_Tp>& __x, const complex<_Tp>& __y)
+    {
+      complex<_Tp> __r = __x;
+      __r *= __y;
+      return __r;
+    }
+
+  template<typename _Tp>
+    inline _GLIBCXX20_CONSTEXPR complex<_Tp>
+    operator*(const complex<_Tp>& __x, const _Tp& __y)
+    {
+      complex<_Tp> __r = __x;
+      __r *= __y;
+      return __r;
+    }
+
+  template<typename _Tp>
+    inline _GLIBCXX20_CONSTEXPR complex<_Tp>
+    operator*(const _Tp& __x, const complex<_Tp>& __y)
+    {
+      complex<_Tp> __r = __y;
+      __r *= __x;
+      return __r;
+    }
+  ///@}
+
+  ///@{
+  ///  Return new complex value @a x divided by @a y.
+  template<typename _Tp>
+    inline _GLIBCXX20_CONSTEXPR complex<_Tp>
+    operator/(const complex<_Tp>& __x, const complex<_Tp>& __y)
+    {
+      complex<_Tp> __r = __x;
+      __r /= __y;
+      return __r;
+    }
+
+  template<typename _Tp>
+    inline _GLIBCXX20_CONSTEXPR complex<_Tp>
+    operator/(const complex<_Tp>& __x, const _Tp& __y)
+    {
+      complex<_Tp> __r = __x;
+      __r /= __y;
+      return __r;
+    }
+
+  template<typename _Tp>
+    inline _GLIBCXX20_CONSTEXPR complex<_Tp>
+    operator/(const _Tp& __x, const complex<_Tp>& __y)
+    {
+      complex<_Tp> __r = __x;
+      __r /= __y;
+      return __r;
+    }
+  ///@}
+
+  ///  Return @a x.
+  template<typename _Tp>
+    inline _GLIBCXX20_CONSTEXPR complex<_Tp>
+    operator+(const complex<_Tp>& __x)
+    { return __x; }
+
+  ///  Return complex negation of @a x.
+  template<typename _Tp>
+    inline _GLIBCXX20_CONSTEXPR complex<_Tp>
+    operator-(const complex<_Tp>& __x)
+    { return complex<_Tp>(-__x.real(), -__x.imag()); }
+
+  ///@{
+  ///  Return true if @a x is equal to @a y.
+  template<typename _Tp>
+    inline _GLIBCXX_CONSTEXPR bool
+    operator==(const complex<_Tp>& __x, const complex<_Tp>& __y)
+    { return __x.real() == __y.real() && __x.imag() == __y.imag(); }
+
+  template<typename _Tp>
+    inline _GLIBCXX_CONSTEXPR bool
+    operator==(const complex<_Tp>& __x, const _Tp& __y)
+    { return __x.real() == __y && __x.imag() == _Tp(); }
+
+#if !(__cpp_impl_three_way_comparison >= 201907L)
+  template<typename _Tp>
+    inline _GLIBCXX_CONSTEXPR bool
+    operator==(const _Tp& __x, const complex<_Tp>& __y)
+    { return __x == __y.real() && _Tp() == __y.imag(); }
+  ///@}
+
+  ///@{
+  ///  Return false if @a x is equal to @a y.
+  template<typename _Tp>
+    inline _GLIBCXX_CONSTEXPR bool
+    operator!=(const complex<_Tp>& __x, const complex<_Tp>& __y)
+    { return __x.real() != __y.real() || __x.imag() != __y.imag(); }
+
+  template<typename _Tp>
+    inline _GLIBCXX_CONSTEXPR bool
+    operator!=(const complex<_Tp>& __x, const _Tp& __y)
+    { return __x.real() != __y || __x.imag() != _Tp(); }
+
+  template<typename _Tp>
+    inline _GLIBCXX_CONSTEXPR bool
+    operator!=(const _Tp& __x, const complex<_Tp>& __y)
+    { return __x != __y.real() || _Tp() != __y.imag(); }
+#endif
+  ///@}
+
+  ///  Extraction operator for complex values.
+  template<typename _Tp, typename _CharT, class _Traits>
+    basic_istream<_CharT, _Traits>&
+    operator>>(basic_istream<_CharT, _Traits>& __is, complex<_Tp>& __x)
+    {
+      bool __fail = true;
+      _CharT __ch;
+      if (__is >> __ch)
+	{
+	  if (_Traits::eq(__ch, __is.widen('(')))
+	    {
+	      _Tp __u;
+	      if (__is >> __u >> __ch)
+		{
+		  const _CharT __rparen = __is.widen(')');
+		  if (_Traits::eq(__ch, __rparen))
+		    {
+		      __x = __u;
+		      __fail = false;
+		    }
+		  else if (_Traits::eq(__ch, __is.widen(',')))
+		    {
+		      _Tp __v;
+		      if (__is >> __v >> __ch)
+			{
+			  if (_Traits::eq(__ch, __rparen))
+			    {
+			      __x = complex<_Tp>(__u, __v);
+			      __fail = false;
+			    }
+			  else
+			    __is.putback(__ch);
+			}
+		    }
+		  else
+		    __is.putback(__ch);
+		}
+	    }
+	  else
+	    {
+	      __is.putback(__ch);
+	      _Tp __u;
+	      if (__is >> __u)
+		{
+		  __x = __u;
+		  __fail = false;
+		}
+	    }
+	}
+      if (__fail)
+	__is.setstate(ios_base::failbit);
+      return __is;
+    }
+
+  ///  Insertion operator for complex values.
+  template<typename _Tp, typename _CharT, class _Traits>
+    basic_ostream<_CharT, _Traits>&
+    operator<<(basic_ostream<_CharT, _Traits>& __os, const complex<_Tp>& __x)
+    {
+      basic_ostringstream<_CharT, _Traits> __s;
+      __s.flags(__os.flags());
+      __s.imbue(__os.getloc());
+      __s.precision(__os.precision());
+      __s << '(' << __x.real() << ',' << __x.imag() << ')';
+      return __os << __s.str();
+    }
+
+  // Values
+#if __cplusplus >= 201103L
+  template<typename _Tp>
+    constexpr _Tp
+    real(const complex<_Tp>& __z)
+    { return __z.real(); }
+
+  template<typename _Tp>
+    constexpr _Tp
+    imag(const complex<_Tp>& __z)
+    { return __z.imag(); }
+#else
+  template<typename _Tp>
+    inline _Tp&
+    real(complex<_Tp>& __z)
+    { return __z.real(); }
+
+  template<typename _Tp>
+    inline const _Tp&
+    real(const complex<_Tp>& __z)
+    { return __z.real(); }
+
+  template<typename _Tp>
+    inline _Tp&
+    imag(complex<_Tp>& __z)
+    { return __z.imag(); }
+
+  template<typename _Tp>
+    inline const _Tp&
+    imag(const complex<_Tp>& __z)
+    { return __z.imag(); }
+#endif
+
+  // 26.2.7/3 abs(__z):  Returns the magnitude of __z.
+  template<typename _Tp>
+    inline _Tp
+    __complex_abs(const complex<_Tp>& __z)
+    {
+      _Tp __x = __z.real();
+      _Tp __y = __z.imag();
+      const _Tp __s = std::max(abs(__x), abs(__y));
+      if (__s == _Tp())  // well ...
+        return __s;
+      __x /= __s;
+      __y /= __s;
+      return __s * sqrt(__x * __x + __y * __y);
+    }
+
+#if _GLIBCXX_USE_C99_COMPLEX
+  inline float
+  __complex_abs(__complex__ float __z) { return __builtin_cabsf(__z); }
+
+  inline double
+  __complex_abs(__complex__ double __z) { return __builtin_cabs(__z); }
+
+  inline long double
+  __complex_abs(const __complex__ long double& __z)
+  { return __builtin_cabsl(__z); }
+
+  template<typename _Tp>
+    inline _Tp
+    abs(const complex<_Tp>& __z) { return __complex_abs(__z.__rep()); }
+#else
+  template<typename _Tp>
+    inline _Tp
+    abs(const complex<_Tp>& __z) { return __complex_abs(__z); }
+#endif
+
+
+  // 26.2.7/4: arg(__z): Returns the phase angle of __z.
+  template<typename _Tp>
+    inline _Tp
+    __complex_arg(const complex<_Tp>& __z)
+    { return  atan2(__z.imag(), __z.real()); }
+
+#if _GLIBCXX_USE_C99_COMPLEX
+  inline float
+  __complex_arg(__complex__ float __z) { return __builtin_cargf(__z); }
+
+  inline double
+  __complex_arg(__complex__ double __z) { return __builtin_carg(__z); }
+
+  inline long double
+  __complex_arg(const __complex__ long double& __z)
+  { return __builtin_cargl(__z); }
+
+  template<typename _Tp>
+    inline _Tp
+    arg(const complex<_Tp>& __z) { return __complex_arg(__z.__rep()); }
+#else
+  template<typename _Tp>
+    inline _Tp
+    arg(const complex<_Tp>& __z) { return __complex_arg(__z); }
+#endif
+
+  // 26.2.7/5: norm(__z) returns the squared magnitude of __z.
+  //     As defined, norm() is -not- a norm is the common mathematical
+  //     sense used in numerics.  The helper class _Norm_helper<> tries to
+  //     distinguish between builtin floating point and the rest, so as
+  //     to deliver an answer as close as possible to the real value.
+  template<bool>
+    struct _Norm_helper
+    {
+      template<typename _Tp>
+        static inline _GLIBCXX20_CONSTEXPR _Tp _S_do_it(const complex<_Tp>& __z)
+        {
+          const _Tp __x = __z.real();
+          const _Tp __y = __z.imag();
+          return __x * __x + __y * __y;
+        }
+    };
+
+  template<>
+    struct _Norm_helper<true>
+    {
+      template<typename _Tp>
+        static inline _GLIBCXX20_CONSTEXPR _Tp _S_do_it(const complex<_Tp>& __z)
+        {
+          //_Tp __res = std::abs(__z);
+          //return __res * __res;
+          const _Tp __x = __z.real();
+          const _Tp __y = __z.imag();
+          return __x * __x + __y * __y;
+        }
+    };
+
+  template<typename _Tp>
+    inline _GLIBCXX20_CONSTEXPR _Tp
+    norm(const complex<_Tp>& __z)
+    {
+      return _Norm_helper<__is_floating<_Tp>::__value
+	&& !_GLIBCXX_FAST_MATH>::_S_do_it(__z);
+    }
+
+  template<typename _Tp>
+    inline complex<_Tp>
+    polar(const _Tp& __rho, const _Tp& __theta)
+    {
+      __glibcxx_assert( __rho >= 0 );
+      return complex<_Tp>(__rho * cos(__theta), __rho * sin(__theta));
+    }
+
+  template<typename _Tp>
+    inline _GLIBCXX20_CONSTEXPR complex<_Tp>
+    conj(const complex<_Tp>& __z)
+    { return complex<_Tp>(__z.real(), -__z.imag()); }
+
+  // Transcendentals
+
+  // 26.2.8/1 cos(__z):  Returns the cosine of __z.
+  template<typename _Tp>
+    inline complex<_Tp>
+    __complex_cos(const complex<_Tp>& __z)
+    {
+      const _Tp __x = __z.real();
+      const _Tp __y = __z.imag();
+      return complex<_Tp>(cos(__x) * cosh(__y), -sin(__x) * sinh(__y));
+    }
+
+#if _GLIBCXX_USE_C99_COMPLEX
+  inline __complex__ float
+  __complex_cos(__complex__ float __z) { return __builtin_ccosf(__z); }
+
+  inline __complex__ double
+  __complex_cos(__complex__ double __z) { return __builtin_ccos(__z); }
+
+  inline __complex__ long double
+  __complex_cos(const __complex__ long double& __z)
+  { return __builtin_ccosl(__z); }
+
+  template<typename _Tp>
+    inline complex<_Tp>
+    cos(const complex<_Tp>& __z) { return __complex_cos(__z.__rep()); }
+#else
+  template<typename _Tp>
+    inline complex<_Tp>
+    cos(const complex<_Tp>& __z) { return __complex_cos(__z); }
+#endif
+
+  // 26.2.8/2 cosh(__z): Returns the hyperbolic cosine of __z.
+  template<typename _Tp>
+    inline complex<_Tp>
+    __complex_cosh(const complex<_Tp>& __z)
+    {
+      const _Tp __x = __z.real();
+      const _Tp __y = __z.imag();
+      return complex<_Tp>(cosh(__x) * cos(__y), sinh(__x) * sin(__y));
+    }
+
+#if _GLIBCXX_USE_C99_COMPLEX
+  inline __complex__ float
+  __complex_cosh(__complex__ float __z) { return __builtin_ccoshf(__z); }
+
+  inline __complex__ double
+  __complex_cosh(__complex__ double __z) { return __builtin_ccosh(__z); }
+
+  inline __complex__ long double
+  __complex_cosh(const __complex__ long double& __z)
+  { return __builtin_ccoshl(__z); }
+
+  template<typename _Tp>
+    inline complex<_Tp>
+    cosh(const complex<_Tp>& __z) { return __complex_cosh(__z.__rep()); }
+#else
+  template<typename _Tp>
+    inline complex<_Tp>
+    cosh(const complex<_Tp>& __z) { return __complex_cosh(__z); }
+#endif
+
+  // 26.2.8/3 exp(__z): Returns the complex base e exponential of x
+  template<typename _Tp>
+    inline complex<_Tp>
+    __complex_exp(const complex<_Tp>& __z)
+    { return std::polar<_Tp>(exp(__z.real()), __z.imag()); }
+
+#if _GLIBCXX_USE_C99_COMPLEX
+  inline __complex__ float
+  __complex_exp(__complex__ float __z) { return __builtin_cexpf(__z); }
+
+  inline __complex__ double
+  __complex_exp(__complex__ double __z) { return __builtin_cexp(__z); }
+
+  inline __complex__ long double
+  __complex_exp(const __complex__ long double& __z)
+  { return __builtin_cexpl(__z); }
+
+  template<typename _Tp>
+    inline complex<_Tp>
+    exp(const complex<_Tp>& __z) { return __complex_exp(__z.__rep()); }
+#else
+  template<typename _Tp>
+    inline complex<_Tp>
+    exp(const complex<_Tp>& __z) { return __complex_exp(__z); }
+#endif
+
+  // 26.2.8/5 log(__z): Returns the natural complex logarithm of __z.
+  //                    The branch cut is along the negative axis.
+  template<typename _Tp>
+    inline complex<_Tp>
+    __complex_log(const complex<_Tp>& __z)
+    { return complex<_Tp>(log(std::abs(__z)), std::arg(__z)); }
+
+#if _GLIBCXX_USE_C99_COMPLEX
+  inline __complex__ float
+  __complex_log(__complex__ float __z) { return __builtin_clogf(__z); }
+
+  inline __complex__ double
+  __complex_log(__complex__ double __z) { return __builtin_clog(__z); }
+
+  inline __complex__ long double
+  __complex_log(const __complex__ long double& __z)
+  { return __builtin_clogl(__z); }
+
+  template<typename _Tp>
+    inline complex<_Tp>
+    log(const complex<_Tp>& __z) { return __complex_log(__z.__rep()); }
+#else
+  template<typename _Tp>
+    inline complex<_Tp>
+    log(const complex<_Tp>& __z) { return __complex_log(__z); }
+#endif
+
+  template<typename _Tp>
+    inline complex<_Tp>
+    log10(const complex<_Tp>& __z)
+    { return std::log(__z) / log(_Tp(10.0)); }
+
+  // 26.2.8/10 sin(__z): Returns the sine of __z.
+  template<typename _Tp>
+    inline complex<_Tp>
+    __complex_sin(const complex<_Tp>& __z)
+    {
+      const _Tp __x = __z.real();
+      const _Tp __y = __z.imag();
+      return complex<_Tp>(sin(__x) * cosh(__y), cos(__x) * sinh(__y));
+    }
+
+#if _GLIBCXX_USE_C99_COMPLEX
+  inline __complex__ float
+  __complex_sin(__complex__ float __z) { return __builtin_csinf(__z); }
+
+  inline __complex__ double
+  __complex_sin(__complex__ double __z) { return __builtin_csin(__z); }
+
+  inline __complex__ long double
+  __complex_sin(const __complex__ long double& __z)
+  { return __builtin_csinl(__z); }
+
+  template<typename _Tp>
+    inline complex<_Tp>
+    sin(const complex<_Tp>& __z) { return __complex_sin(__z.__rep()); }
+#else
+  template<typename _Tp>
+    inline complex<_Tp>
+    sin(const complex<_Tp>& __z) { return __complex_sin(__z); }
+#endif
+
+  // 26.2.8/11 sinh(__z): Returns the hyperbolic sine of __z.
+  template<typename _Tp>
+    inline complex<_Tp>
+    __complex_sinh(const complex<_Tp>& __z)
+    {
+      const _Tp __x = __z.real();
+      const _Tp  __y = __z.imag();
+      return complex<_Tp>(sinh(__x) * cos(__y), cosh(__x) * sin(__y));
+    }
+
+#if _GLIBCXX_USE_C99_COMPLEX
+  inline __complex__ float
+  __complex_sinh(__complex__ float __z) { return __builtin_csinhf(__z); }
+
+  inline __complex__ double
+  __complex_sinh(__complex__ double __z) { return __builtin_csinh(__z); }
+
+  inline __complex__ long double
+  __complex_sinh(const __complex__ long double& __z)
+  { return __builtin_csinhl(__z); }
+
+  template<typename _Tp>
+    inline complex<_Tp>
+    sinh(const complex<_Tp>& __z) { return __complex_sinh(__z.__rep()); }
+#else
+  template<typename _Tp>
+    inline complex<_Tp>
+    sinh(const complex<_Tp>& __z) { return __complex_sinh(__z); }
+#endif
+
+  // 26.2.8/13 sqrt(__z): Returns the complex square root of __z.
+  //                     The branch cut is on the negative axis.
+  template<typename _Tp>
+    complex<_Tp>
+    __complex_sqrt(const complex<_Tp>& __z)
+    {
+      _Tp __x = __z.real();
+      _Tp __y = __z.imag();
+
+      if (__x == _Tp())
+        {
+          _Tp __t = sqrt(abs(__y) / 2);
+          return complex<_Tp>(__t, __y < _Tp() ? -__t : __t);
+        }
+      else
+        {
+          _Tp __t = sqrt(2 * (std::abs(__z) + abs(__x)));
+          _Tp __u = __t / 2;
+          return __x > _Tp()
+            ? complex<_Tp>(__u, __y / __t)
+            : complex<_Tp>(abs(__y) / __t, __y < _Tp() ? -__u : __u);
+        }
+    }
+
+#if _GLIBCXX_USE_C99_COMPLEX
+  inline __complex__ float
+  __complex_sqrt(__complex__ float __z) { return __builtin_csqrtf(__z); }
+
+  inline __complex__ double
+  __complex_sqrt(__complex__ double __z) { return __builtin_csqrt(__z); }
+
+  inline __complex__ long double
+  __complex_sqrt(const __complex__ long double& __z)
+  { return __builtin_csqrtl(__z); }
+
+  template<typename _Tp>
+    inline complex<_Tp>
+    sqrt(const complex<_Tp>& __z) { return __complex_sqrt(__z.__rep()); }
+#else
+  template<typename _Tp>
+    inline complex<_Tp>
+    sqrt(const complex<_Tp>& __z) { return __complex_sqrt(__z); }
+#endif
+
+  // 26.2.8/14 tan(__z):  Return the complex tangent of __z.
+
+  template<typename _Tp>
+    inline complex<_Tp>
+    __complex_tan(const complex<_Tp>& __z)
+    { return std::sin(__z) / std::cos(__z); }
+
+#if _GLIBCXX_USE_C99_COMPLEX
+  inline __complex__ float
+  __complex_tan(__complex__ float __z) { return __builtin_ctanf(__z); }
+
+  inline __complex__ double
+  __complex_tan(__complex__ double __z) { return __builtin_ctan(__z); }
+
+  inline __complex__ long double
+  __complex_tan(const __complex__ long double& __z)
+  { return __builtin_ctanl(__z); }
+
+  template<typename _Tp>
+    inline complex<_Tp>
+    tan(const complex<_Tp>& __z) { return __complex_tan(__z.__rep()); }
+#else
+  template<typename _Tp>
+    inline complex<_Tp>
+    tan(const complex<_Tp>& __z) { return __complex_tan(__z); }
+#endif
+
+
+  // 26.2.8/15 tanh(__z):  Returns the hyperbolic tangent of __z.
+
+  template<typename _Tp>
+    inline complex<_Tp>
+    __complex_tanh(const complex<_Tp>& __z)
+    { return std::sinh(__z) / std::cosh(__z); }
+
+#if _GLIBCXX_USE_C99_COMPLEX
+  inline __complex__ float
+  __complex_tanh(__complex__ float __z) { return __builtin_ctanhf(__z); }
+
+  inline __complex__ double
+  __complex_tanh(__complex__ double __z) { return __builtin_ctanh(__z); }
+
+  inline __complex__ long double
+  __complex_tanh(const __complex__ long double& __z)
+  { return __builtin_ctanhl(__z); }
+
+  template<typename _Tp>
+    inline complex<_Tp>
+    tanh(const complex<_Tp>& __z) { return __complex_tanh(__z.__rep()); }
+#else
+  template<typename _Tp>
+    inline complex<_Tp>
+    tanh(const complex<_Tp>& __z) { return __complex_tanh(__z); }
+#endif
+
+
+  // 26.2.8/9  pow(__x, __y): Returns the complex power base of __x
+  //                          raised to the __y-th power.  The branch
+  //                          cut is on the negative axis.
+  template<typename _Tp>
+    complex<_Tp>
+    __complex_pow_unsigned(complex<_Tp> __x, unsigned __n)
+    {
+      complex<_Tp> __y = __n % 2 ? __x : complex<_Tp>(1);
+
+      while (__n >>= 1)
+        {
+          __x *= __x;
+          if (__n % 2)
+            __y *= __x;
+        }
+
+      return __y;
+    }
+
+  // In C++11 mode we used to implement the resolution of
+  // DR 844. complex pow return type is ambiguous.
+  // thus the following overload was disabled in that mode.  However, doing
+  // that causes all sorts of issues, see, for example:
+  //   http://gcc.gnu.org/ml/libstdc++/2013-01/msg00058.html
+  // and also PR57974.
+  template<typename _Tp>
+    inline complex<_Tp>
+    pow(const complex<_Tp>& __z, int __n)
+    {
+      return __n < 0
+	? complex<_Tp>(1) / std::__complex_pow_unsigned(__z, -(unsigned)__n)
+        : std::__complex_pow_unsigned(__z, __n);
+    }
+
+  template<typename _Tp>
+    complex<_Tp>
+    pow(const complex<_Tp>& __x, const _Tp& __y)
+    {
+#if ! _GLIBCXX_USE_C99_COMPLEX
+      if (__x == _Tp())
+	return _Tp();
+#endif
+      if (__x.imag() == _Tp() && __x.real() > _Tp())
+        return pow(__x.real(), __y);
+
+      complex<_Tp> __t = std::log(__x);
+      return std::polar<_Tp>(exp(__y * __t.real()), __y * __t.imag());
+    }
+
+  template<typename _Tp>
+    inline complex<_Tp>
+    __complex_pow(const complex<_Tp>& __x, const complex<_Tp>& __y)
+    { return __x == _Tp() ? _Tp() : std::exp(__y * std::log(__x)); }
+
+#if _GLIBCXX_USE_C99_COMPLEX
+  inline __complex__ float
+  __complex_pow(__complex__ float __x, __complex__ float __y)
+  { return __builtin_cpowf(__x, __y); }
+
+  inline __complex__ double
+  __complex_pow(__complex__ double __x, __complex__ double __y)
+  { return __builtin_cpow(__x, __y); }
+
+  inline __complex__ long double
+  __complex_pow(const __complex__ long double& __x,
+		const __complex__ long double& __y)
+  { return __builtin_cpowl(__x, __y); }
+
+  template<typename _Tp>
+    inline complex<_Tp>
+    pow(const complex<_Tp>& __x, const complex<_Tp>& __y)
+    { return __complex_pow(__x.__rep(), __y.__rep()); }
+#else
+  template<typename _Tp>
+    inline complex<_Tp>
+    pow(const complex<_Tp>& __x, const complex<_Tp>& __y)
+    { return __complex_pow(__x, __y); }
+#endif
+
+  template<typename _Tp>
+    inline complex<_Tp>
+    pow(const _Tp& __x, const complex<_Tp>& __y)
+    {
+      return __x > _Tp() ? std::polar<_Tp>(pow(__x, __y.real()),
+					   __y.imag() * log(__x))
+	                 : std::pow(complex<_Tp>(__x), __y);
+    }
+
+  /// 26.2.3  complex specializations
+  /// complex<float> specialization
+  template<>
+    class complex<float>
+    {
+    public:
+      typedef float value_type;
+      typedef __complex__ float _ComplexT;
+
+      _GLIBCXX_CONSTEXPR complex(_ComplexT __z) : _M_value(__z) { }
+
+      _GLIBCXX_CONSTEXPR complex(float __r = 0.0f, float __i = 0.0f)
+#if __cplusplus >= 201103L
+      : _M_value{ __r, __i } { }
+#else
+      {
+	__real__ _M_value = __r;
+	__imag__ _M_value = __i;
+      }
+#endif
+
+      explicit _GLIBCXX_CONSTEXPR complex(const complex<double>&);
+      explicit _GLIBCXX_CONSTEXPR complex(const complex<long double>&);
+
+#if __cplusplus >= 201103L
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // DR 387. std::complex over-encapsulated.
+      __attribute ((__abi_tag__ ("cxx11")))
+      constexpr float
+      real() const { return __real__ _M_value; }
+
+      __attribute ((__abi_tag__ ("cxx11")))
+      constexpr float
+      imag() const { return __imag__ _M_value; }
+#else
+      float&
+      real() { return __real__ _M_value; }
+
+      const float&
+      real() const { return __real__ _M_value; }
+
+      float&
+      imag() { return __imag__ _M_value; }
+
+      const float&
+      imag() const { return __imag__ _M_value; }
+#endif
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // DR 387. std::complex over-encapsulated.
+      _GLIBCXX20_CONSTEXPR void
+      real(float __val) { __real__ _M_value = __val; }
+
+      _GLIBCXX20_CONSTEXPR void
+      imag(float __val) { __imag__ _M_value = __val; }
+
+      _GLIBCXX20_CONSTEXPR complex&
+      operator=(float __f)
+      {
+	_M_value = __f;
+	return *this;
+      }
+
+      _GLIBCXX20_CONSTEXPR complex&
+      operator+=(float __f)
+      {
+	_M_value += __f;
+	return *this;
+      }
+
+      _GLIBCXX20_CONSTEXPR complex&
+      operator-=(float __f)
+      {
+	_M_value -= __f;
+	return *this;
+      }
+
+      _GLIBCXX20_CONSTEXPR complex&
+      operator*=(float __f)
+      {
+	_M_value *= __f;
+	return *this;
+      }
+
+      _GLIBCXX20_CONSTEXPR complex&
+      operator/=(float __f)
+      {
+	_M_value /= __f;
+	return *this;
+      }
+
+      // Let the compiler synthesize the copy and assignment
+      // operator.  It always does a pretty good job.
+#if __cplusplus >= 201103L
+      _GLIBCXX14_CONSTEXPR complex& operator=(const complex&) = default;
+#endif
+
+      template<typename _Tp>
+        _GLIBCXX20_CONSTEXPR complex&
+        operator=(const complex<_Tp>&  __z)
+	{
+	  __real__ _M_value = __z.real();
+	  __imag__ _M_value = __z.imag();
+	  return *this;
+	}
+
+      template<typename _Tp>
+        _GLIBCXX20_CONSTEXPR complex&
+        operator+=(const complex<_Tp>& __z)
+	{
+	  _M_value += __z.__rep();
+	  return *this;
+	}
+
+      template<class _Tp>
+        _GLIBCXX20_CONSTEXPR complex&
+        operator-=(const complex<_Tp>& __z)
+	{
+	  _M_value -= __z.__rep();
+	  return *this;
+	}
+
+      template<class _Tp>
+        _GLIBCXX20_CONSTEXPR complex&
+        operator*=(const complex<_Tp>& __z)
+	{
+	  const _ComplexT __t = __z.__rep();
+	  _M_value *= __t;
+	  return *this;
+	}
+
+      template<class _Tp>
+        _GLIBCXX20_CONSTEXPR complex&
+        operator/=(const complex<_Tp>& __z)
+	{
+	  const _ComplexT __t = __z.__rep();
+	  _M_value /= __t;
+	  return *this;
+	}
+
+      _GLIBCXX_CONSTEXPR _ComplexT __rep() const { return _M_value; }
+
+    private:
+      _ComplexT _M_value;
+    };
+
+  /// 26.2.3  complex specializations
+  /// complex<double> specialization
+  template<>
+    class complex<double>
+    {
+    public:
+      typedef double value_type;
+      typedef __complex__ double _ComplexT;
+
+      _GLIBCXX_CONSTEXPR complex(_ComplexT __z) : _M_value(__z) { }
+
+      _GLIBCXX_CONSTEXPR complex(double __r = 0.0, double __i = 0.0)
+#if __cplusplus >= 201103L
+      : _M_value{ __r, __i } { }
+#else
+      {
+	__real__ _M_value = __r;
+	__imag__ _M_value = __i;
+      }
+#endif
+
+      _GLIBCXX_CONSTEXPR complex(const complex<float>& __z)
+      : _M_value(__z.__rep()) { }
+
+      explicit _GLIBCXX_CONSTEXPR complex(const complex<long double>&);
+
+#if __cplusplus >= 201103L
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // DR 387. std::complex over-encapsulated.
+      __attribute ((__abi_tag__ ("cxx11")))
+      constexpr double
+      real() const { return __real__ _M_value; }
+
+      __attribute ((__abi_tag__ ("cxx11")))
+      constexpr double
+      imag() const { return __imag__ _M_value; }
+#else
+      double&
+      real() { return __real__ _M_value; }
+
+      const double&
+      real() const { return __real__ _M_value; }
+
+      double&
+      imag() { return __imag__ _M_value; }
+
+      const double&
+      imag() const { return __imag__ _M_value; }
+#endif
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // DR 387. std::complex over-encapsulated.
+      _GLIBCXX20_CONSTEXPR void
+      real(double __val) { __real__ _M_value = __val; }
+
+      _GLIBCXX20_CONSTEXPR void
+      imag(double __val) { __imag__ _M_value = __val; }
+
+      _GLIBCXX20_CONSTEXPR complex&
+      operator=(double __d)
+      {
+	_M_value = __d;
+	return *this;
+      }
+
+      _GLIBCXX20_CONSTEXPR complex&
+      operator+=(double __d)
+      {
+	_M_value += __d;
+	return *this;
+      }
+
+      _GLIBCXX20_CONSTEXPR complex&
+      operator-=(double __d)
+      {
+	_M_value -= __d;
+	return *this;
+      }
+
+      _GLIBCXX20_CONSTEXPR complex&
+      operator*=(double __d)
+      {
+	_M_value *= __d;
+	return *this;
+      }
+
+      _GLIBCXX20_CONSTEXPR complex&
+      operator/=(double __d)
+      {
+	_M_value /= __d;
+	return *this;
+      }
+
+      // The compiler will synthesize this, efficiently.
+#if __cplusplus >= 201103L
+      _GLIBCXX14_CONSTEXPR complex& operator=(const complex&) = default;
+#endif
+
+      template<typename _Tp>
+        _GLIBCXX20_CONSTEXPR complex&
+        operator=(const complex<_Tp>& __z)
+	{
+	  _M_value = __z.__rep();
+	  return *this;
+	}
+
+      template<typename _Tp>
+        _GLIBCXX20_CONSTEXPR complex&
+        operator+=(const complex<_Tp>& __z)
+	{
+	  _M_value += __z.__rep();
+	  return *this;
+	}
+
+      template<typename _Tp>
+        _GLIBCXX20_CONSTEXPR complex&
+        operator-=(const complex<_Tp>& __z)
+	{
+	  _M_value -= __z.__rep();
+	  return *this;
+	}
+
+      template<typename _Tp>
+        _GLIBCXX20_CONSTEXPR complex&
+        operator*=(const complex<_Tp>& __z)
+	{
+	  const _ComplexT __t = __z.__rep();
+	  _M_value *= __t;
+	  return *this;
+	}
+
+      template<typename _Tp>
+        _GLIBCXX20_CONSTEXPR complex&
+        operator/=(const complex<_Tp>& __z)
+	{
+	  const _ComplexT __t = __z.__rep();
+	  _M_value /= __t;
+	  return *this;
+	}
+
+      _GLIBCXX_CONSTEXPR _ComplexT __rep() const { return _M_value; }
+
+    private:
+      _ComplexT _M_value;
+    };
+
+  /// 26.2.3  complex specializations
+  /// complex<long double> specialization
+  template<>
+    class complex<long double>
+    {
+    public:
+      typedef long double value_type;
+      typedef __complex__ long double _ComplexT;
+
+      _GLIBCXX_CONSTEXPR complex(_ComplexT __z) : _M_value(__z) { }
+
+      _GLIBCXX_CONSTEXPR complex(long double __r = 0.0L,
+				 long double __i = 0.0L)
+#if __cplusplus >= 201103L
+      : _M_value{ __r, __i } { }
+#else
+      {
+	__real__ _M_value = __r;
+	__imag__ _M_value = __i;
+      }
+#endif
+
+      _GLIBCXX_CONSTEXPR complex(const complex<float>& __z)
+      : _M_value(__z.__rep()) { }
+
+      _GLIBCXX_CONSTEXPR complex(const complex<double>& __z)
+      : _M_value(__z.__rep()) { }
+
+#if __cplusplus >= 201103L
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // DR 387. std::complex over-encapsulated.
+      __attribute ((__abi_tag__ ("cxx11")))
+      constexpr long double
+      real() const { return __real__ _M_value; }
+
+      __attribute ((__abi_tag__ ("cxx11")))
+      constexpr long double
+      imag() const { return __imag__ _M_value; }
+#else
+      long double&
+      real() { return __real__ _M_value; }
+
+      const long double&
+      real() const { return __real__ _M_value; }
+
+      long double&
+      imag() { return __imag__ _M_value; }
+
+      const long double&
+      imag() const { return __imag__ _M_value; }
+#endif
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // DR 387. std::complex over-encapsulated.
+      _GLIBCXX20_CONSTEXPR void
+      real(long double __val) { __real__ _M_value = __val; }
+
+      _GLIBCXX20_CONSTEXPR void
+      imag(long double __val) { __imag__ _M_value = __val; }
+
+      _GLIBCXX20_CONSTEXPR complex&
+      operator=(long double __r)
+      {
+	_M_value = __r;
+	return *this;
+      }
+
+      _GLIBCXX20_CONSTEXPR complex&
+      operator+=(long double __r)
+      {
+	_M_value += __r;
+	return *this;
+      }
+
+      _GLIBCXX20_CONSTEXPR complex&
+      operator-=(long double __r)
+      {
+	_M_value -= __r;
+	return *this;
+      }
+
+      _GLIBCXX20_CONSTEXPR complex&
+      operator*=(long double __r)
+      {
+	_M_value *= __r;
+	return *this;
+      }
+
+      _GLIBCXX20_CONSTEXPR complex&
+      operator/=(long double __r)
+      {
+	_M_value /= __r;
+	return *this;
+      }
+
+      // The compiler knows how to do this efficiently
+#if __cplusplus >= 201103L
+      _GLIBCXX14_CONSTEXPR complex& operator=(const complex&) = default;
+#endif
+
+      template<typename _Tp>
+        _GLIBCXX20_CONSTEXPR complex&
+        operator=(const complex<_Tp>& __z)
+	{
+	  _M_value = __z.__rep();
+	  return *this;
+	}
+
+      template<typename _Tp>
+        _GLIBCXX20_CONSTEXPR complex&
+	operator+=(const complex<_Tp>& __z)
+	{
+	  _M_value += __z.__rep();
+	  return *this;
+	}
+
+      template<typename _Tp>
+        _GLIBCXX20_CONSTEXPR complex&
+	operator-=(const complex<_Tp>& __z)
+	{
+	  _M_value -= __z.__rep();
+	  return *this;
+	}
+
+      template<typename _Tp>
+        _GLIBCXX20_CONSTEXPR complex&
+	operator*=(const complex<_Tp>& __z)
+	{
+	  const _ComplexT __t = __z.__rep();
+	  _M_value *= __t;
+	  return *this;
+	}
+
+      template<typename _Tp>
+        _GLIBCXX20_CONSTEXPR complex&
+	operator/=(const complex<_Tp>& __z)
+	{
+	  const _ComplexT __t = __z.__rep();
+	  _M_value /= __t;
+	  return *this;
+	}
+
+      _GLIBCXX_CONSTEXPR _ComplexT __rep() const { return _M_value; }
+
+    private:
+      _ComplexT _M_value;
+    };
+
+  // These bits have to be at the end of this file, so that the
+  // specializations have all been defined.
+  inline _GLIBCXX_CONSTEXPR
+  complex<float>::complex(const complex<double>& __z)
+  : _M_value(__z.__rep()) { }
+
+  inline _GLIBCXX_CONSTEXPR
+  complex<float>::complex(const complex<long double>& __z)
+  : _M_value(__z.__rep()) { }
+
+  inline _GLIBCXX_CONSTEXPR
+  complex<double>::complex(const complex<long double>& __z)
+  : _M_value(__z.__rep()) { }
+
+  // Inhibit implicit instantiations for required instantiations,
+  // which are defined via explicit instantiations elsewhere.
+  // NB:  This syntax is a GNU extension.
+#if _GLIBCXX_EXTERN_TEMPLATE
+  extern template istream& operator>>(istream&, complex<float>&);
+  extern template ostream& operator<<(ostream&, const complex<float>&);
+  extern template istream& operator>>(istream&, complex<double>&);
+  extern template ostream& operator<<(ostream&, const complex<double>&);
+  extern template istream& operator>>(istream&, complex<long double>&);
+  extern template ostream& operator<<(ostream&, const complex<long double>&);
+
+#ifdef _GLIBCXX_USE_WCHAR_T
+  extern template wistream& operator>>(wistream&, complex<float>&);
+  extern template wostream& operator<<(wostream&, const complex<float>&);
+  extern template wistream& operator>>(wistream&, complex<double>&);
+  extern template wostream& operator<<(wostream&, const complex<double>&);
+  extern template wistream& operator>>(wistream&, complex<long double>&);
+  extern template wostream& operator<<(wostream&, const complex<long double>&);
+#endif
+#endif
+
+  /// @} group complex_numbers
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#if __cplusplus >= 201103L
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  // Forward declarations.
+  template<typename _Tp> std::complex<_Tp> acos(const std::complex<_Tp>&);
+  template<typename _Tp> std::complex<_Tp> asin(const std::complex<_Tp>&);
+  template<typename _Tp> std::complex<_Tp> atan(const std::complex<_Tp>&);
+
+  template<typename _Tp> std::complex<_Tp> acosh(const std::complex<_Tp>&);
+  template<typename _Tp> std::complex<_Tp> asinh(const std::complex<_Tp>&);
+  template<typename _Tp> std::complex<_Tp> atanh(const std::complex<_Tp>&);
+  // DR 595.
+  template<typename _Tp> _Tp               fabs(const std::complex<_Tp>&);
+
+  template<typename _Tp>
+    inline std::complex<_Tp>
+    __complex_acos(const std::complex<_Tp>& __z)
+    {
+      const std::complex<_Tp> __t = std::asin(__z);
+      const _Tp __pi_2 = 1.5707963267948966192313216916397514L;
+      return std::complex<_Tp>(__pi_2 - __t.real(), -__t.imag());
+    }
+
+#if _GLIBCXX_USE_C99_COMPLEX_TR1
+  inline __complex__ float
+  __complex_acos(__complex__ float __z)
+  { return __builtin_cacosf(__z); }
+
+  inline __complex__ double
+  __complex_acos(__complex__ double __z)
+  { return __builtin_cacos(__z); }
+
+  inline __complex__ long double
+  __complex_acos(const __complex__ long double& __z)
+  { return __builtin_cacosl(__z); }
+
+  template<typename _Tp>
+    inline std::complex<_Tp>
+    acos(const std::complex<_Tp>& __z)
+    { return __complex_acos(__z.__rep()); }
+#else
+  /// acos(__z) [8.1.2].
+  //  Effects:  Behaves the same as C99 function cacos, defined
+  //            in subclause 7.3.5.1.
+  template<typename _Tp>
+    inline std::complex<_Tp>
+    acos(const std::complex<_Tp>& __z)
+    { return __complex_acos(__z); }
+#endif
+
+  template<typename _Tp>
+    inline std::complex<_Tp>
+    __complex_asin(const std::complex<_Tp>& __z)
+    {
+      std::complex<_Tp> __t(-__z.imag(), __z.real());
+      __t = std::asinh(__t);
+      return std::complex<_Tp>(__t.imag(), -__t.real());
+    }
+
+#if _GLIBCXX_USE_C99_COMPLEX_TR1
+  inline __complex__ float
+  __complex_asin(__complex__ float __z)
+  { return __builtin_casinf(__z); }
+
+  inline __complex__ double
+  __complex_asin(__complex__ double __z)
+  { return __builtin_casin(__z); }
+
+  inline __complex__ long double
+  __complex_asin(const __complex__ long double& __z)
+  { return __builtin_casinl(__z); }
+
+  template<typename _Tp>
+    inline std::complex<_Tp>
+    asin(const std::complex<_Tp>& __z)
+    { return __complex_asin(__z.__rep()); }
+#else
+  /// asin(__z) [8.1.3].
+  //  Effects:  Behaves the same as C99 function casin, defined
+  //            in subclause 7.3.5.2.
+  template<typename _Tp>
+    inline std::complex<_Tp>
+    asin(const std::complex<_Tp>& __z)
+    { return __complex_asin(__z); }
+#endif
+
+  template<typename _Tp>
+    std::complex<_Tp>
+    __complex_atan(const std::complex<_Tp>& __z)
+    {
+      const _Tp __r2 = __z.real() * __z.real();
+      const _Tp __x = _Tp(1.0) - __r2 - __z.imag() * __z.imag();
+
+      _Tp __num = __z.imag() + _Tp(1.0);
+      _Tp __den = __z.imag() - _Tp(1.0);
+
+      __num = __r2 + __num * __num;
+      __den = __r2 + __den * __den;
+
+      return std::complex<_Tp>(_Tp(0.5) * atan2(_Tp(2.0) * __z.real(), __x),
+			       _Tp(0.25) * log(__num / __den));
+    }
+
+#if _GLIBCXX_USE_C99_COMPLEX_TR1
+  inline __complex__ float
+  __complex_atan(__complex__ float __z)
+  { return __builtin_catanf(__z); }
+
+  inline __complex__ double
+  __complex_atan(__complex__ double __z)
+  { return __builtin_catan(__z); }
+
+  inline __complex__ long double
+  __complex_atan(const __complex__ long double& __z)
+  { return __builtin_catanl(__z); }
+
+  template<typename _Tp>
+    inline std::complex<_Tp>
+    atan(const std::complex<_Tp>& __z)
+    { return __complex_atan(__z.__rep()); }
+#else
+  /// atan(__z) [8.1.4].
+  //  Effects:  Behaves the same as C99 function catan, defined
+  //            in subclause 7.3.5.3.
+  template<typename _Tp>
+    inline std::complex<_Tp>
+    atan(const std::complex<_Tp>& __z)
+    { return __complex_atan(__z); }
+#endif
+
+  template<typename _Tp>
+    std::complex<_Tp>
+    __complex_acosh(const std::complex<_Tp>& __z)
+    {
+      // Kahan's formula.
+      return _Tp(2.0) * std::log(std::sqrt(_Tp(0.5) * (__z + _Tp(1.0)))
+				 + std::sqrt(_Tp(0.5) * (__z - _Tp(1.0))));
+    }
+
+#if _GLIBCXX_USE_C99_COMPLEX_TR1
+  inline __complex__ float
+  __complex_acosh(__complex__ float __z)
+  { return __builtin_cacoshf(__z); }
+
+  inline __complex__ double
+  __complex_acosh(__complex__ double __z)
+  { return __builtin_cacosh(__z); }
+
+  inline __complex__ long double
+  __complex_acosh(const __complex__ long double& __z)
+  { return __builtin_cacoshl(__z); }
+
+  template<typename _Tp>
+    inline std::complex<_Tp>
+    acosh(const std::complex<_Tp>& __z)
+    { return __complex_acosh(__z.__rep()); }
+#else
+  /// acosh(__z) [8.1.5].
+  //  Effects:  Behaves the same as C99 function cacosh, defined
+  //            in subclause 7.3.6.1.
+  template<typename _Tp>
+    inline std::complex<_Tp>
+    acosh(const std::complex<_Tp>& __z)
+    { return __complex_acosh(__z); }
+#endif
+
+  template<typename _Tp>
+    std::complex<_Tp>
+    __complex_asinh(const std::complex<_Tp>& __z)
+    {
+      std::complex<_Tp> __t((__z.real() - __z.imag())
+			    * (__z.real() + __z.imag()) + _Tp(1.0),
+			    _Tp(2.0) * __z.real() * __z.imag());
+      __t = std::sqrt(__t);
+
+      return std::log(__t + __z);
+    }
+
+#if _GLIBCXX_USE_C99_COMPLEX_TR1
+  inline __complex__ float
+  __complex_asinh(__complex__ float __z)
+  { return __builtin_casinhf(__z); }
+
+  inline __complex__ double
+  __complex_asinh(__complex__ double __z)
+  { return __builtin_casinh(__z); }
+
+  inline __complex__ long double
+  __complex_asinh(const __complex__ long double& __z)
+  { return __builtin_casinhl(__z); }
+
+  template<typename _Tp>
+    inline std::complex<_Tp>
+    asinh(const std::complex<_Tp>& __z)
+    { return __complex_asinh(__z.__rep()); }
+#else
+  /// asinh(__z) [8.1.6].
+  //  Effects:  Behaves the same as C99 function casin, defined
+  //            in subclause 7.3.6.2.
+  template<typename _Tp>
+    inline std::complex<_Tp>
+    asinh(const std::complex<_Tp>& __z)
+    { return __complex_asinh(__z); }
+#endif
+
+  template<typename _Tp>
+    std::complex<_Tp>
+    __complex_atanh(const std::complex<_Tp>& __z)
+    {
+      const _Tp __i2 = __z.imag() * __z.imag();
+      const _Tp __x = _Tp(1.0) - __i2 - __z.real() * __z.real();
+
+      _Tp __num = _Tp(1.0) + __z.real();
+      _Tp __den = _Tp(1.0) - __z.real();
+
+      __num = __i2 + __num * __num;
+      __den = __i2 + __den * __den;
+
+      return std::complex<_Tp>(_Tp(0.25) * (log(__num) - log(__den)),
+			       _Tp(0.5) * atan2(_Tp(2.0) * __z.imag(), __x));
+    }
+
+#if _GLIBCXX_USE_C99_COMPLEX_TR1
+  inline __complex__ float
+  __complex_atanh(__complex__ float __z)
+  { return __builtin_catanhf(__z); }
+
+  inline __complex__ double
+  __complex_atanh(__complex__ double __z)
+  { return __builtin_catanh(__z); }
+
+  inline __complex__ long double
+  __complex_atanh(const __complex__ long double& __z)
+  { return __builtin_catanhl(__z); }
+
+  template<typename _Tp>
+    inline std::complex<_Tp>
+    atanh(const std::complex<_Tp>& __z)
+    { return __complex_atanh(__z.__rep()); }
+#else
+  /// atanh(__z) [8.1.7].
+  //  Effects:  Behaves the same as C99 function catanh, defined
+  //            in subclause 7.3.6.3.
+  template<typename _Tp>
+    inline std::complex<_Tp>
+    atanh(const std::complex<_Tp>& __z)
+    { return __complex_atanh(__z); }
+#endif
+
+  template<typename _Tp>
+    inline _Tp
+    /// fabs(__z) [8.1.8].
+    //  Effects:  Behaves the same as C99 function cabs, defined
+    //            in subclause 7.3.8.1.
+    fabs(const std::complex<_Tp>& __z)
+    { return std::abs(__z); }
+
+  /// Additional overloads [8.1.9].
+  template<typename _Tp>
+    inline typename __gnu_cxx::__promote<_Tp>::__type
+    arg(_Tp __x)
+    {
+      typedef typename __gnu_cxx::__promote<_Tp>::__type __type;
+#if (_GLIBCXX11_USE_C99_MATH && !_GLIBCXX_USE_C99_FP_MACROS_DYNAMIC)
+      return std::signbit(__x) ? __type(3.1415926535897932384626433832795029L)
+	                       : __type();
+#else
+      return std::arg(std::complex<__type>(__x));
+#endif
+    }
+
+  template<typename _Tp>
+    _GLIBCXX_CONSTEXPR inline typename __gnu_cxx::__promote<_Tp>::__type
+    imag(_Tp)
+    { return _Tp(); }
+
+  template<typename _Tp>
+    _GLIBCXX20_CONSTEXPR inline typename __gnu_cxx::__promote<_Tp>::__type
+    norm(_Tp __x)
+    {
+      typedef typename __gnu_cxx::__promote<_Tp>::__type __type;
+      return __type(__x) * __type(__x);
+    }
+
+  template<typename _Tp>
+    _GLIBCXX_CONSTEXPR inline typename __gnu_cxx::__promote<_Tp>::__type
+    real(_Tp __x)
+    { return __x; }
+
+  template<typename _Tp, typename _Up>
+    inline std::complex<typename __gnu_cxx::__promote_2<_Tp, _Up>::__type>
+    pow(const std::complex<_Tp>& __x, const _Up& __y)
+    {
+      typedef typename __gnu_cxx::__promote_2<_Tp, _Up>::__type __type;
+      return std::pow(std::complex<__type>(__x), __type(__y));
+    }
+
+  template<typename _Tp, typename _Up>
+    inline std::complex<typename __gnu_cxx::__promote_2<_Tp, _Up>::__type>
+    pow(const _Tp& __x, const std::complex<_Up>& __y)
+    {
+      typedef typename __gnu_cxx::__promote_2<_Tp, _Up>::__type __type;
+      return std::pow(__type(__x), std::complex<__type>(__y));
+    }
+
+  template<typename _Tp, typename _Up>
+    inline std::complex<typename __gnu_cxx::__promote_2<_Tp, _Up>::__type>
+    pow(const std::complex<_Tp>& __x, const std::complex<_Up>& __y)
+    {
+      typedef typename __gnu_cxx::__promote_2<_Tp, _Up>::__type __type;
+      return std::pow(std::complex<__type>(__x),
+		      std::complex<__type>(__y));
+    }
+
+  // Forward declarations.
+  // DR 781.
+  template<typename _Tp>
+    std::complex<_Tp> proj(const std::complex<_Tp>&);
+
+  // Generic implementation of std::proj, does not work for infinities.
+  template<typename _Tp>
+    inline std::complex<_Tp>
+    __complex_proj(const std::complex<_Tp>& __z)
+    { return __z; }
+
+#if _GLIBCXX_USE_C99_COMPLEX
+  inline complex<float>
+  __complex_proj(const complex<float>& __z)
+  { return __builtin_cprojf(__z.__rep()); }
+
+  inline complex<double>
+  __complex_proj(const complex<double>& __z)
+  { return __builtin_cproj(__z.__rep()); }
+
+  inline complex<long double>
+  __complex_proj(const complex<long double>& __z)
+  { return __builtin_cprojl(__z.__rep()); }
+#elif defined _GLIBCXX_USE_C99_MATH_TR1
+  inline complex<float>
+  __complex_proj(const complex<float>& __z)
+  {
+    if (__builtin_isinf(__z.real()) || __builtin_isinf(__z.imag()))
+      return complex<float>(__builtin_inff(),
+			    __builtin_copysignf(0.0f, __z.imag()));
+    return __z;
+  }
+
+  inline complex<double>
+  __complex_proj(const complex<double>& __z)
+  {
+    if (__builtin_isinf(__z.real()) || __builtin_isinf(__z.imag()))
+      return complex<double>(__builtin_inf(),
+			     __builtin_copysign(0.0, __z.imag()));
+    return __z;
+  }
+
+  inline complex<long double>
+  __complex_proj(const complex<long double>& __z)
+  {
+    if (__builtin_isinf(__z.real()) || __builtin_isinf(__z.imag()))
+      return complex<long double>(__builtin_infl(),
+				  __builtin_copysignl(0.0l, __z.imag()));
+    return __z;
+  }
+#endif
+
+  template<typename _Tp>
+    inline std::complex<_Tp>
+    proj(const std::complex<_Tp>& __z)
+    { return __complex_proj(__z); }
+
+  // Overload for scalars
+  template<typename _Tp>
+    inline std::complex<typename __gnu_cxx::__promote<_Tp>::__type>
+    proj(_Tp __x)
+    {
+      typedef typename __gnu_cxx::__promote<_Tp>::__type __type;
+      return std::proj(std::complex<__type>(__x));
+    }
+
+  template<typename _Tp>
+    inline _GLIBCXX20_CONSTEXPR
+	std::complex<typename __gnu_cxx::__promote<_Tp>::__type>
+    conj(_Tp __x)
+    {
+      typedef typename __gnu_cxx::__promote<_Tp>::__type __type;
+      return std::complex<__type>(__x, -__type());
+    }
+
+#if __cplusplus > 201103L
+
+inline namespace literals {
+inline namespace complex_literals {
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wliteral-suffix"
+#define __cpp_lib_complex_udls 201309L
+
+  constexpr std::complex<float>
+  operator""if(long double __num)
+  { return std::complex<float>{0.0F, static_cast<float>(__num)}; }
+
+  constexpr std::complex<float>
+  operator""if(unsigned long long __num)
+  { return std::complex<float>{0.0F, static_cast<float>(__num)}; }
+
+  constexpr std::complex<double>
+  operator""i(long double __num)
+  { return std::complex<double>{0.0, static_cast<double>(__num)}; }
+
+  constexpr std::complex<double>
+  operator""i(unsigned long long __num)
+  { return std::complex<double>{0.0, static_cast<double>(__num)}; }
+
+  constexpr std::complex<long double>
+  operator""il(long double __num)
+  { return std::complex<long double>{0.0L, __num}; }
+
+  constexpr std::complex<long double>
+  operator""il(unsigned long long __num)
+  { return std::complex<long double>{0.0L, static_cast<long double>(__num)}; }
+
+#pragma GCC diagnostic pop
+} // inline namespace complex_literals
+} // inline namespace literals
+
+#endif // C++14
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif  // C++11
+
+#endif  /* _GLIBCXX_COMPLEX */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@complex.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@complex.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@condition_variable b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@condition_variable
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@@ -0,0 +1,450 @@
+// <condition_variable> -*- C++ -*-
+
+// Copyright (C) 2008-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file include/condition_variable
+ *  This is a Standard C++ Library header.
+ */
+
+#ifndef _GLIBCXX_CONDITION_VARIABLE
+#define _GLIBCXX_CONDITION_VARIABLE 1
+
+#pragma GCC system_header
+
+#if __cplusplus < 201103L
+# include <bits/c++0x_warning.h>
+#else
+
+#include <bits/chrono.h>
+#include <bits/std_mutex.h>
+#include <bits/unique_lock.h>
+#include <bits/alloc_traits.h>
+#include <bits/shared_ptr.h>
+#include <bits/cxxabi_forced.h>
+
+#if __cplusplus > 201703L
+# include <stop_token>
+#endif
+
+#if defined(_GLIBCXX_HAS_GTHREADS)
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /**
+   * @defgroup condition_variables Condition Variables
+   * @ingroup concurrency
+   *
+   * Classes for condition_variable support.
+   * @{
+   */
+
+  /// cv_status
+  enum class cv_status { no_timeout, timeout };
+
+  /// condition_variable
+  class condition_variable
+  {
+    using steady_clock = chrono::steady_clock;
+    using system_clock = chrono::system_clock;
+#ifdef _GLIBCXX_USE_PTHREAD_COND_CLOCKWAIT
+    using __clock_t = steady_clock;
+#else
+    using __clock_t = system_clock;
+#endif
+
+    __condvar _M_cond;
+
+  public:
+    typedef __gthread_cond_t* 		native_handle_type;
+
+    condition_variable() noexcept;
+    ~condition_variable() noexcept;
+
+    condition_variable(const condition_variable&) = delete;
+    condition_variable& operator=(const condition_variable&) = delete;
+
+    void
+    notify_one() noexcept;
+
+    void
+    notify_all() noexcept;
+
+    void
+    wait(unique_lock<mutex>& __lock);
+
+    template<typename _Predicate>
+      void
+      wait(unique_lock<mutex>& __lock, _Predicate __p)
+      {
+	while (!__p())
+	  wait(__lock);
+      }
+
+#ifdef _GLIBCXX_USE_PTHREAD_COND_CLOCKWAIT
+    template<typename _Duration>
+      cv_status
+      wait_until(unique_lock<mutex>& __lock,
+		 const chrono::time_point<steady_clock, _Duration>& __atime)
+      { return __wait_until_impl(__lock, __atime); }
+#endif
+
+    template<typename _Duration>
+      cv_status
+      wait_until(unique_lock<mutex>& __lock,
+		 const chrono::time_point<system_clock, _Duration>& __atime)
+      { return __wait_until_impl(__lock, __atime); }
+
+    template<typename _Clock, typename _Duration>
+      cv_status
+      wait_until(unique_lock<mutex>& __lock,
+		 const chrono::time_point<_Clock, _Duration>& __atime)
+      {
+#if __cplusplus > 201703L
+	static_assert(chrono::is_clock_v<_Clock>);
+#endif
+	using __s_dur = typename __clock_t::duration;
+	const typename _Clock::time_point __c_entry = _Clock::now();
+	const __clock_t::time_point __s_entry = __clock_t::now();
+	const auto __delta = __atime - __c_entry;
+	const auto __s_atime = __s_entry +
+	  chrono::__detail::ceil<__s_dur>(__delta);
+
+	if (__wait_until_impl(__lock, __s_atime) == cv_status::no_timeout)
+	  return cv_status::no_timeout;
+	// We got a timeout when measured against __clock_t but
+	// we need to check against the caller-supplied clock
+	// to tell whether we should return a timeout.
+	if (_Clock::now() < __atime)
+	  return cv_status::no_timeout;
+	return cv_status::timeout;
+      }
+
+    template<typename _Clock, typename _Duration, typename _Predicate>
+      bool
+      wait_until(unique_lock<mutex>& __lock,
+		 const chrono::time_point<_Clock, _Duration>& __atime,
+		 _Predicate __p)
+      {
+	while (!__p())
+	  if (wait_until(__lock, __atime) == cv_status::timeout)
+	    return __p();
+	return true;
+      }
+
+    template<typename _Rep, typename _Period>
+      cv_status
+      wait_for(unique_lock<mutex>& __lock,
+	       const chrono::duration<_Rep, _Period>& __rtime)
+      {
+	using __dur = typename steady_clock::duration;
+	return wait_until(__lock,
+			  steady_clock::now() +
+			  chrono::__detail::ceil<__dur>(__rtime));
+      }
+
+    template<typename _Rep, typename _Period, typename _Predicate>
+      bool
+      wait_for(unique_lock<mutex>& __lock,
+	       const chrono::duration<_Rep, _Period>& __rtime,
+	       _Predicate __p)
+      {
+	using __dur = typename steady_clock::duration;
+	return wait_until(__lock,
+			  steady_clock::now() +
+			  chrono::__detail::ceil<__dur>(__rtime),
+			  std::move(__p));
+      }
+
+    native_handle_type
+    native_handle()
+    { return _M_cond.native_handle(); }
+
+  private:
+#ifdef _GLIBCXX_USE_PTHREAD_COND_CLOCKWAIT
+    template<typename _Dur>
+      cv_status
+      __wait_until_impl(unique_lock<mutex>& __lock,
+			const chrono::time_point<steady_clock, _Dur>& __atime)
+      {
+	auto __s = chrono::time_point_cast<chrono::seconds>(__atime);
+	auto __ns = chrono::duration_cast<chrono::nanoseconds>(__atime - __s);
+
+	__gthread_time_t __ts =
+	  {
+	    static_cast<std::time_t>(__s.time_since_epoch().count()),
+	    static_cast<long>(__ns.count())
+	  };
+
+	_M_cond.wait_until(*__lock.mutex(), CLOCK_MONOTONIC, __ts);
+
+	return (steady_clock::now() < __atime
+		? cv_status::no_timeout : cv_status::timeout);
+      }
+#endif
+
+    template<typename _Dur>
+      cv_status
+      __wait_until_impl(unique_lock<mutex>& __lock,
+			const chrono::time_point<system_clock, _Dur>& __atime)
+      {
+	auto __s = chrono::time_point_cast<chrono::seconds>(__atime);
+	auto __ns = chrono::duration_cast<chrono::nanoseconds>(__atime - __s);
+
+	__gthread_time_t __ts =
+	  {
+	    static_cast<std::time_t>(__s.time_since_epoch().count()),
+	    static_cast<long>(__ns.count())
+	  };
+
+	_M_cond.wait_until(*__lock.mutex(), __ts);
+
+	return (system_clock::now() < __atime
+		? cv_status::no_timeout : cv_status::timeout);
+      }
+  };
+
+  void
+  notify_all_at_thread_exit(condition_variable&, unique_lock<mutex>);
+
+  struct __at_thread_exit_elt
+  {
+    __at_thread_exit_elt* _M_next;
+    void (*_M_cb)(void*);
+  };
+
+  inline namespace _V2 {
+
+  /// condition_variable_any
+  // Like above, but mutex is not required to have try_lock.
+  class condition_variable_any
+  {
+#ifdef _GLIBCXX_USE_PTHREAD_COND_CLOCKWAIT
+    using __clock_t = chrono::steady_clock;
+#else
+    using __clock_t = chrono::system_clock;
+#endif
+    condition_variable			_M_cond;
+    shared_ptr<mutex>			_M_mutex;
+
+    // scoped unlock - unlocks in ctor, re-locks in dtor
+    template<typename _Lock>
+      struct _Unlock
+      {
+	explicit _Unlock(_Lock& __lk) : _M_lock(__lk) { __lk.unlock(); }
+
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+	~_Unlock() noexcept(false)
+	{
+	  if (uncaught_exception())
+	    {
+	      __try
+	      { _M_lock.lock(); }
+	      __catch(const __cxxabiv1::__forced_unwind&)
+	      { __throw_exception_again; }
+	      __catch(...)
+	      { }
+	    }
+	  else
+	    _M_lock.lock();
+	}
+#pragma GCC diagnostic pop
+
+	_Unlock(const _Unlock&) = delete;
+	_Unlock& operator=(const _Unlock&) = delete;
+
+	_Lock& _M_lock;
+      };
+
+  public:
+    condition_variable_any() : _M_mutex(std::make_shared<mutex>()) { }
+    ~condition_variable_any() = default;
+
+    condition_variable_any(const condition_variable_any&) = delete;
+    condition_variable_any& operator=(const condition_variable_any&) = delete;
+
+    void
+    notify_one() noexcept
+    {
+      lock_guard<mutex> __lock(*_M_mutex);
+      _M_cond.notify_one();
+    }
+
+    void
+    notify_all() noexcept
+    {
+      lock_guard<mutex> __lock(*_M_mutex);
+      _M_cond.notify_all();
+    }
+
+    template<typename _Lock>
+      void
+      wait(_Lock& __lock)
+      {
+	shared_ptr<mutex> __mutex = _M_mutex;
+	unique_lock<mutex> __my_lock(*__mutex);
+	_Unlock<_Lock> __unlock(__lock);
+	// *__mutex must be unlocked before re-locking __lock so move
+	// ownership of *__mutex lock to an object with shorter lifetime.
+	unique_lock<mutex> __my_lock2(std::move(__my_lock));
+	_M_cond.wait(__my_lock2);
+      }
+
+
+    template<typename _Lock, typename _Predicate>
+      void
+      wait(_Lock& __lock, _Predicate __p)
+      {
+	while (!__p())
+	  wait(__lock);
+      }
+
+    template<typename _Lock, typename _Clock, typename _Duration>
+      cv_status
+      wait_until(_Lock& __lock,
+		 const chrono::time_point<_Clock, _Duration>& __atime)
+      {
+	shared_ptr<mutex> __mutex = _M_mutex;
+	unique_lock<mutex> __my_lock(*__mutex);
+	_Unlock<_Lock> __unlock(__lock);
+	// *__mutex must be unlocked before re-locking __lock so move
+	// ownership of *__mutex lock to an object with shorter lifetime.
+	unique_lock<mutex> __my_lock2(std::move(__my_lock));
+	return _M_cond.wait_until(__my_lock2, __atime);
+      }
+
+    template<typename _Lock, typename _Clock,
+	     typename _Duration, typename _Predicate>
+      bool
+      wait_until(_Lock& __lock,
+		 const chrono::time_point<_Clock, _Duration>& __atime,
+		 _Predicate __p)
+      {
+	while (!__p())
+	  if (wait_until(__lock, __atime) == cv_status::timeout)
+	    return __p();
+	return true;
+      }
+
+    template<typename _Lock, typename _Rep, typename _Period>
+      cv_status
+      wait_for(_Lock& __lock, const chrono::duration<_Rep, _Period>& __rtime)
+      { return wait_until(__lock, __clock_t::now() + __rtime); }
+
+    template<typename _Lock, typename _Rep,
+	     typename _Period, typename _Predicate>
+      bool
+      wait_for(_Lock& __lock,
+	       const chrono::duration<_Rep, _Period>& __rtime, _Predicate __p)
+      { return wait_until(__lock, __clock_t::now() + __rtime, std::move(__p)); }
+
+#ifdef __cpp_lib_jthread
+    template <class _Lock, class _Predicate>
+    bool wait(_Lock& __lock,
+              stop_token __stoken,
+              _Predicate __p)
+    {
+      if (__stoken.stop_requested())
+        {
+          return __p();
+        }
+ 
+      std::stop_callback __cb(__stoken, [this] { notify_all(); });
+      shared_ptr<mutex> __mutex = _M_mutex;
+      while (!__p())
+        {
+          unique_lock<mutex> __my_lock(*__mutex);
+          if (__stoken.stop_requested())
+            {
+              return false;
+            }
+          // *__mutex must be unlocked before re-locking __lock so move
+          // ownership of *__mutex lock to an object with shorter lifetime.
+          _Unlock<_Lock> __unlock(__lock);
+          unique_lock<mutex> __my_lock2(std::move(__my_lock));
+          _M_cond.wait(__my_lock2);
+        }
+      return true;
+    }
+
+    template <class _Lock, class _Clock, class _Duration, class _Predicate>
+    bool wait_until(_Lock& __lock,
+                    stop_token __stoken,
+                    const chrono::time_point<_Clock, _Duration>& __abs_time,
+                    _Predicate __p)
+    {
+      if (__stoken.stop_requested())
+        {
+          return __p();
+        }
+
+      std::stop_callback __cb(__stoken, [this] { notify_all(); });
+      shared_ptr<mutex> __mutex = _M_mutex;
+      while (!__p())
+        {
+          bool __stop;
+          {
+            unique_lock<mutex> __my_lock(*__mutex);
+            if (__stoken.stop_requested())
+              {
+                return false;
+              }
+            _Unlock<_Lock> __u(__lock);
+            unique_lock<mutex> __my_lock2(std::move(__my_lock));
+            const auto __status = _M_cond.wait_until(__my_lock2, __abs_time);
+            __stop = (__status == std::cv_status::timeout) || __stoken.stop_requested();
+          }
+          if (__stop)
+            {
+              return __p();
+            }
+        }
+      return true;
+    }
+
+    template <class _Lock, class _Rep, class _Period, class _Predicate>
+    bool wait_for(_Lock& __lock,
+                  stop_token __stoken,
+                  const chrono::duration<_Rep, _Period>& __rel_time,
+                  _Predicate __p)
+    {
+      auto __abst = std::chrono::steady_clock::now() + __rel_time;
+      return wait_until(__lock,
+                        std::move(__stoken),
+                        __abst,
+                        std::move(__p));
+    }
+#endif
+  };
+
+  } // end inline namespace
+
+  /// @} group condition_variables
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif // _GLIBCXX_HAS_GTHREADS
+#endif // C++11
+#endif // _GLIBCXX_CONDITION_VARIABLE
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@csetjmp
@@ -0,0 +1,61 @@
+// -*- C++ -*- forwarding header.
+
+// Copyright (C) 1997-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file csetjmp
+ *  This is a Standard C++ Library file.  You should @c \#include this file
+ *  in your programs, rather than any of the @a *.h implementation files.
+ *
+ *  This is the C++ version of the Standard C Library header @c setjmp.h,
+ *  and its contents are (mostly) the same as that header, but are all
+ *  contained in the namespace @c std (except for names which are defined
+ *  as macros in C).
+ */
+
+//
+// ISO C++ 14882: 20.4.6  C library
+//
+
+#pragma GCC system_header
+
+#include <bits/c++config.h>
+#include <setjmp.h>
+
+#ifndef _GLIBCXX_CSETJMP
+#define _GLIBCXX_CSETJMP 1
+
+// Get rid of those macros defined in <setjmp.h> in lieu of real functions.
+#undef longjmp
+
+// Adhere to section 17.4.1.2 clause 5 of ISO 14882:1998
+#ifndef setjmp
+#define setjmp(env) setjmp (env)
+#endif
+
+namespace std
+{
+  using ::jmp_buf;
+  using ::longjmp;
+} // namespace std
+
+#endif
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@@ -0,0 +1,57 @@
+// -*- C++ -*- forwarding header.
+
+// Copyright (C) 1997-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file csignal
+ *  This is a Standard C++ Library file.  You should @c \#include this file
+ *  in your programs, rather than any of the @a *.h implementation files.
+ *
+ *  This is the C++ version of the Standard C Library header @c signal.h,
+ *  and its contents are (mostly) the same as that header, but are all
+ *  contained in the namespace @c std (except for names which are defined
+ *  as macros in C).
+ */
+
+//
+// ISO C++ 14882: 20.4.6  C library
+//
+
+#pragma GCC system_header
+
+#include <bits/c++config.h>
+#include <signal.h>
+
+#ifndef _GLIBCXX_CSIGNAL
+#define _GLIBCXX_CSIGNAL 1
+
+// Get rid of those macros defined in <signal.h> in lieu of real functions.
+#undef raise
+
+namespace std
+{
+  using ::sig_atomic_t;
+  using ::signal;
+  using ::raise;
+} // namespace std
+
+#endif
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@@ -0,0 +1,44 @@
+// <cstdalign> -*- C++ -*-
+
+// Copyright (C) 2011-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file include/cstdalign
+ *  This is a Standard C++ Library header.
+ */
+
+#pragma GCC system_header
+
+#ifndef _GLIBCXX_CSTDALIGN
+#define _GLIBCXX_CSTDALIGN 1
+
+#if __cplusplus < 201103L
+#  include <bits/c++0x_warning.h>
+#else
+#  include <bits/c++config.h>
+#  if _GLIBCXX_HAVE_STDALIGN_H
+#    include <stdalign.h>
+#  endif
+#endif
+
+#endif 
+
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@@ -0,0 +1,58 @@
+// -*- C++ -*- forwarding header.
+
+// Copyright (C) 1997-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file include/cstdarg
+ *  This is a Standard C++ Library file.  You should @c \#include this file
+ *  in your programs, rather than any of the @a *.h implementation files.
+ *
+ *  This is the C++ version of the Standard C Library header @c stdarg.h,
+ *  and its contents are (mostly) the same as that header, but are all
+ *  contained in the namespace @c std (except for names which are defined
+ *  as macros in C).
+ */
+
+//
+// ISO C++ 14882: 20.4.6  C library
+//
+
+#pragma GCC system_header
+
+#undef __need___va_list
+#include <bits/c++config.h>
+#include <stdarg.h>
+
+#ifndef _GLIBCXX_CSTDARG
+#define _GLIBCXX_CSTDARG 1
+
+// Adhere to section 17.4.1.2 clause 5 of ISO 14882:1998
+#ifndef va_end
+#define va_end(ap) va_end (ap)
+#endif
+
+namespace std
+{
+  using ::va_list;
+} // namespace std
+
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@cstdarg.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@cstdarg.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@cstdbool b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@cstdbool
new file mode 100644
index 0000000000000000000000000000000000000000..95b22ca723a9ab9c45380525f0d1e821bea28115
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@cstdbool
@@ -0,0 +1,44 @@
+// <cstdbool> -*- C++ -*-
+
+// Copyright (C) 2007-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file include/cstdbool
+ *  This is a Standard C++ Library header.
+ */
+
+#pragma GCC system_header
+
+#ifndef _GLIBCXX_CSTDBOOL
+#define _GLIBCXX_CSTDBOOL 1
+
+#if __cplusplus < 201103L
+#  include <bits/c++0x_warning.h>
+#else
+#  include <bits/c++config.h>
+#  if _GLIBCXX_HAVE_STDBOOL_H
+#    include <stdbool.h>
+#  endif
+#endif
+
+#endif 
+
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new file mode 100644
index 0000000000000000000000000000000000000000..4970c2dfcfbf055c3ffd22ae5c35c4ad82859717
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@cstddef
@@ -0,0 +1,180 @@
+// -*- C++ -*- forwarding header.
+
+// Copyright (C) 1997-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file cstddef
+ *  This is a Standard C++ Library file.  You should @c \#include this file
+ *  in your programs, rather than any of the @a *.h implementation files.
+ *
+ *  This is the C++ version of the Standard C Library header @c stddef.h,
+ *  and its contents are (mostly) the same as that header, but are all
+ *  contained in the namespace @c std (except for names which are defined
+ *  as macros in C).
+ */
+
+//
+// ISO C++ 14882: 18.1  Types
+//
+
+#ifndef _GLIBCXX_CSTDDEF
+#define _GLIBCXX_CSTDDEF 1
+
+#pragma GCC system_header
+
+#undef __need_wchar_t
+#undef __need_ptrdiff_t
+#undef __need_size_t
+#undef __need_NULL
+#undef __need_wint_t
+#include <bits/c++config.h>
+#include <stddef.h>
+
+extern "C++"
+{
+#if __cplusplus >= 201103L
+namespace std
+{
+  // We handle size_t, ptrdiff_t, and nullptr_t in c++config.h.
+  using ::max_align_t;
+}
+#endif // C++11
+
+#if __cplusplus >= 201703L
+namespace std
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+#define __cpp_lib_byte 201603L
+
+  /// std::byte
+  enum class byte : unsigned char {};
+
+  template<typename _IntegerType> struct __byte_operand { };
+  template<> struct __byte_operand<bool> { using __type = byte; };
+  template<> struct __byte_operand<char> { using __type = byte; };
+  template<> struct __byte_operand<signed char> { using __type = byte; };
+  template<> struct __byte_operand<unsigned char> { using __type = byte; };
+  template<> struct __byte_operand<wchar_t> { using __type = byte; };
+#ifdef _GLIBCXX_USE_CHAR8_T
+  template<> struct __byte_operand<char8_t> { using __type = byte; };
+#endif
+  template<> struct __byte_operand<char16_t> { using __type = byte; };
+  template<> struct __byte_operand<char32_t> { using __type = byte; };
+  template<> struct __byte_operand<short> { using __type = byte; };
+  template<> struct __byte_operand<unsigned short> { using __type = byte; };
+  template<> struct __byte_operand<int> { using __type = byte; };
+  template<> struct __byte_operand<unsigned int> { using __type = byte; };
+  template<> struct __byte_operand<long> { using __type = byte; };
+  template<> struct __byte_operand<unsigned long> { using __type = byte; };
+  template<> struct __byte_operand<long long> { using __type = byte; };
+  template<> struct __byte_operand<unsigned long long> { using __type = byte; };
+#if defined(__GLIBCXX_TYPE_INT_N_0)
+  template<> struct __byte_operand<__GLIBCXX_TYPE_INT_N_0>
+  { using __type = byte; };
+  template<> struct __byte_operand<unsigned __GLIBCXX_TYPE_INT_N_0>
+  { using __type = byte; };
+#endif
+#if defined(__GLIBCXX_TYPE_INT_N_1)
+  template<> struct __byte_operand<__GLIBCXX_TYPE_INT_N_1>
+  { using __type = byte; };
+  template<> struct __byte_operand<unsigned __GLIBCXX_TYPE_INT_N_1>
+  { using __type = byte; };
+#endif
+#if defined(__GLIBCXX_TYPE_INT_N_2)
+  template<> struct __byte_operand<__GLIBCXX_TYPE_INT_N_2>
+  { using __type = byte; };
+  template<> struct __byte_operand<unsigned __GLIBCXX_TYPE_INT_N_2>
+  { using __type = byte; };
+#endif
+  template<typename _IntegerType>
+    struct __byte_operand<const _IntegerType>
+    : __byte_operand<_IntegerType> { };
+  template<typename _IntegerType>
+    struct __byte_operand<volatile _IntegerType>
+    : __byte_operand<_IntegerType> { };
+  template<typename _IntegerType>
+    struct __byte_operand<const volatile _IntegerType>
+    : __byte_operand<_IntegerType> { };
+
+  template<typename _IntegerType>
+    using __byte_op_t = typename __byte_operand<_IntegerType>::__type;
+
+  template<typename _IntegerType>
+    constexpr __byte_op_t<_IntegerType>
+    operator<<(byte __b, _IntegerType __shift) noexcept
+    { return (byte)(unsigned char)((unsigned)__b << __shift); }
+
+  template<typename _IntegerType>
+    constexpr __byte_op_t<_IntegerType>
+    operator>>(byte __b, _IntegerType __shift) noexcept
+    { return (byte)(unsigned char)((unsigned)__b >> __shift); }
+
+  constexpr byte
+  operator|(byte __l, byte __r) noexcept
+  { return (byte)(unsigned char)((unsigned)__l | (unsigned)__r); }
+
+  constexpr byte
+  operator&(byte __l, byte __r) noexcept
+  { return (byte)(unsigned char)((unsigned)__l & (unsigned)__r); }
+
+  constexpr byte
+  operator^(byte __l, byte __r) noexcept
+  { return (byte)(unsigned char)((unsigned)__l ^ (unsigned)__r); }
+
+  constexpr byte
+  operator~(byte __b) noexcept
+  { return (byte)(unsigned char)~(unsigned)__b; }
+
+  template<typename _IntegerType>
+    constexpr __byte_op_t<_IntegerType>&
+    operator<<=(byte& __b, _IntegerType __shift) noexcept
+    { return __b = __b << __shift; }
+
+  template<typename _IntegerType>
+    constexpr __byte_op_t<_IntegerType>&
+    operator>>=(byte& __b, _IntegerType __shift) noexcept
+    { return __b = __b >> __shift; }
+
+  constexpr byte&
+  operator|=(byte& __l, byte __r) noexcept
+  { return __l = __l | __r; }
+
+  constexpr byte&
+  operator&=(byte& __l, byte __r) noexcept
+  { return __l = __l & __r; }
+
+  constexpr byte&
+  operator^=(byte& __l, byte __r) noexcept
+  { return __l = __l ^ __r; }
+
+  template<typename _IntegerType>
+    [[nodiscard]]
+    constexpr _IntegerType
+    to_integer(__byte_op_t<_IntegerType> __b) noexcept
+    { return _IntegerType(__b); }
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+#endif // C++17
+} // extern "C++"
+
+#endif // _GLIBCXX_CSTDDEF
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@cstddef.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@cstddef.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@cstdint b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@cstdint
new file mode 100644
index 0000000000000000000000000000000000000000..4490d06f0996e7e709c27f900ef5f3ee94aa78c7
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@cstdint
@@ -0,0 +1,91 @@
+// <cstdint> -*- C++ -*-
+
+// Copyright (C) 2007-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file include/cstdint
+ *  This is a Standard C++ Library header.
+ */
+
+#ifndef _GLIBCXX_CSTDINT
+#define _GLIBCXX_CSTDINT 1
+
+#pragma GCC system_header
+
+#if __cplusplus < 201103L
+# include <bits/c++0x_warning.h>
+#else
+
+#include <bits/c++config.h>
+
+#if _GLIBCXX_HAVE_STDINT_H
+# include <stdint.h>
+#endif
+
+namespace std
+{
+#ifdef _GLIBCXX_USE_C99_STDINT_TR1
+  using ::int8_t;
+  using ::int16_t;
+  using ::int32_t;
+  using ::int64_t;
+
+  using ::int_fast8_t;
+  using ::int_fast16_t;
+  using ::int_fast32_t;
+  using ::int_fast64_t;
+
+  using ::int_least8_t;
+  using ::int_least16_t;
+  using ::int_least32_t;
+  using ::int_least64_t;
+
+  using ::intmax_t;
+  using ::intptr_t;
+  
+  using ::uint8_t;
+  using ::uint16_t;
+  using ::uint32_t;
+  using ::uint64_t;
+
+  using ::uint_fast8_t;
+  using ::uint_fast16_t;
+  using ::uint_fast32_t;
+  using ::uint_fast64_t;
+
+  using ::uint_least8_t;
+  using ::uint_least16_t;
+  using ::uint_least32_t;
+  using ::uint_least64_t;
+
+  using ::uintmax_t;
+  using ::uintptr_t;
+#else // !_GLIBCXX_USE_C99_STDINT_TR1
+  // Define the minimum needed for <ratio>, <chrono> etc.
+  using intmax_t = __INTMAX_TYPE__;
+  using uintmax_t = __UINTMAX_TYPE__;
+#endif // _GLIBCXX_USE_C99_STDINT_TR1
+} // namespace std
+
+#endif // C++11
+
+#endif // _GLIBCXX_CSTDINT
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@cstdint.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@cstdint.blob
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new file mode 100644
index 0000000000000000000000000000000000000000..4c7e136ed42030c0b88f4120f04257d75ebfbba5
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@cstdio
@@ -0,0 +1,194 @@
+// -*- C++ -*- forwarding header.
+
+// Copyright (C) 1997-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file include/cstdio
+ *  This is a Standard C++ Library file.  You should @c \#include this file
+ *  in your programs, rather than any of the @a *.h implementation files.
+ *
+ *  This is the C++ version of the Standard C Library header @c stdio.h,
+ *  and its contents are (mostly) the same as that header, but are all
+ *  contained in the namespace @c std (except for names which are defined
+ *  as macros in C).
+ */
+
+//
+// ISO C++ 14882: 27.8.2  C Library files
+//
+
+#pragma GCC system_header
+
+#include <bits/c++config.h>
+#include <stdio.h>
+
+#ifndef _GLIBCXX_CSTDIO
+#define _GLIBCXX_CSTDIO 1
+
+#if __cplusplus <= 201103L && !defined(_GLIBCXX_HAVE_GETS)
+extern "C" char* gets (char* __s) __attribute__((__deprecated__));
+#endif
+
+// Get rid of those macros defined in <stdio.h> in lieu of real functions.
+#undef clearerr
+#undef fclose
+#undef feof
+#undef ferror
+#undef fflush
+#undef fgetc
+#undef fgetpos
+#undef fgets
+#undef fopen
+#undef fprintf
+#undef fputc
+#undef fputs
+#undef fread
+#undef freopen
+#undef fscanf
+#undef fseek
+#undef fsetpos
+#undef ftell
+#undef fwrite
+#undef getc
+#undef getchar
+#if __cplusplus <= 201103L
+# undef gets
+#endif
+#undef perror
+#undef printf
+#undef putc
+#undef putchar
+#undef puts
+#undef remove
+#undef rename
+#undef rewind
+#undef scanf
+#undef setbuf
+#undef setvbuf
+#undef sprintf
+#undef sscanf
+#undef tmpfile
+#undef tmpnam
+#undef ungetc
+#undef vfprintf
+#undef vprintf
+#undef vsprintf
+
+namespace std
+{
+  using ::FILE;
+  using ::fpos_t;
+
+  using ::clearerr;
+  using ::fclose;
+  using ::feof;
+  using ::ferror;
+  using ::fflush;
+  using ::fgetc;
+  using ::fgetpos;
+  using ::fgets;
+  using ::fopen;
+  using ::fprintf;
+  using ::fputc;
+  using ::fputs;
+  using ::fread;
+  using ::freopen;
+  using ::fscanf;
+  using ::fseek;
+  using ::fsetpos;
+  using ::ftell;
+  using ::fwrite;
+  using ::getc;
+  using ::getchar;
+#if __cplusplus <= 201103L
+  // LWG 2249
+  using ::gets;
+#endif
+  using ::perror;
+  using ::printf;
+  using ::putc;
+  using ::putchar;
+  using ::puts;
+  using ::remove;
+  using ::rename;
+  using ::rewind;
+  using ::scanf;
+  using ::setbuf;
+  using ::setvbuf;
+  using ::sprintf;
+  using ::sscanf;
+  using ::tmpfile;
+#if _GLIBCXX_USE_TMPNAM
+  using ::tmpnam;
+#endif
+  using ::ungetc;
+  using ::vfprintf;
+  using ::vprintf;
+  using ::vsprintf;
+} // namespace
+
+#if _GLIBCXX_USE_C99_STDIO
+
+#undef snprintf
+#undef vfscanf
+#undef vscanf
+#undef vsnprintf
+#undef vsscanf
+
+namespace __gnu_cxx
+{
+#if _GLIBCXX_USE_C99_CHECK || _GLIBCXX_USE_C99_DYNAMIC
+  extern "C" int
+  (snprintf)(char * __restrict, std::size_t, const char * __restrict, ...)
+  throw ();
+  extern "C" int
+  (vfscanf)(FILE * __restrict, const char * __restrict, __gnuc_va_list);
+  extern "C" int (vscanf)(const char * __restrict, __gnuc_va_list);
+  extern "C" int
+  (vsnprintf)(char * __restrict, std::size_t, const char * __restrict,
+	      __gnuc_va_list) throw ();
+  extern "C" int
+  (vsscanf)(const char * __restrict, const char * __restrict, __gnuc_va_list)
+  throw ();
+#endif
+
+#if !_GLIBCXX_USE_C99_DYNAMIC
+  using ::snprintf;
+  using ::vfscanf;
+  using ::vscanf;
+  using ::vsnprintf;
+  using ::vsscanf;
+#endif
+} // namespace __gnu_cxx
+
+namespace std
+{
+  using ::__gnu_cxx::snprintf;
+  using ::__gnu_cxx::vfscanf;
+  using ::__gnu_cxx::vscanf;
+  using ::__gnu_cxx::vsnprintf;
+  using ::__gnu_cxx::vsscanf;
+} // namespace std
+
+#endif // _GLIBCXX_USE_C99_STDIO
+
+#endif
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@cstdlib
@@ -0,0 +1,261 @@
+// -*- C++ -*- forwarding header.
+
+// Copyright (C) 1997-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file include/cstdlib
+ *  This is a Standard C++ Library file.  You should @c \#include this file
+ *  in your programs, rather than any of the @a *.h implementation files.
+ *
+ *  This is the C++ version of the Standard C Library header @c stdlib.h,
+ *  and its contents are (mostly) the same as that header, but are all
+ *  contained in the namespace @c std (except for names which are defined
+ *  as macros in C).
+ */
+
+//
+// ISO C++ 14882: 20.4.6  C library
+//
+
+#pragma GCC system_header
+
+#include <bits/c++config.h>
+
+#ifndef _GLIBCXX_CSTDLIB
+#define _GLIBCXX_CSTDLIB 1
+
+#if !_GLIBCXX_HOSTED
+// The C standard does not require a freestanding implementation to
+// provide <stdlib.h>.  However, the C++ standard does still require
+// <cstdlib> -- but only the functionality mentioned in
+// [lib.support.start.term].
+
+#define EXIT_SUCCESS 0
+#define EXIT_FAILURE 1
+
+namespace std
+{
+  extern "C" void abort(void) throw () _GLIBCXX_NORETURN;
+  extern "C" int atexit(void (*)(void)) throw ();
+  extern "C" void exit(int) throw () _GLIBCXX_NORETURN;
+#if __cplusplus >= 201103L
+# ifdef _GLIBCXX_HAVE_AT_QUICK_EXIT
+  extern "C" int at_quick_exit(void (*)(void)) throw ();
+# endif
+# ifdef _GLIBCXX_HAVE_QUICK_EXIT
+  extern "C" void quick_exit(int) throw() _GLIBCXX_NORETURN;
+# endif
+#endif
+} // namespace std
+
+#else
+
+// Need to ensure this finds the C library's <stdlib.h> not a libstdc++
+// wrapper that might already be installed later in the include search path.
+#define _GLIBCXX_INCLUDE_NEXT_C_HEADERS
+#include_next <stdlib.h>
+#undef _GLIBCXX_INCLUDE_NEXT_C_HEADERS
+#include <bits/std_abs.h>
+
+// Get rid of those macros defined in <stdlib.h> in lieu of real functions.
+#undef abort
+#if __cplusplus >= 201703L && defined(_GLIBCXX_HAVE_ALIGNED_ALLOC)
+# undef aligned_alloc
+#endif
+#undef atexit
+#if __cplusplus >= 201103L
+# ifdef _GLIBCXX_HAVE_AT_QUICK_EXIT
+#  undef at_quick_exit
+# endif
+#endif
+#undef atof
+#undef atoi
+#undef atol
+#undef bsearch
+#undef calloc
+#undef div
+#undef exit
+#undef free
+#undef getenv
+#undef labs
+#undef ldiv
+#undef malloc
+#undef mblen
+#undef mbstowcs
+#undef mbtowc
+#undef qsort
+#if __cplusplus >= 201103L
+# ifdef _GLIBCXX_HAVE_QUICK_EXIT
+#  undef quick_exit
+# endif
+#endif
+#undef rand
+#undef realloc
+#undef srand
+#undef strtod
+#undef strtol
+#undef strtoul
+#undef system
+#undef wcstombs
+#undef wctomb
+
+extern "C++"
+{
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  using ::div_t;
+  using ::ldiv_t;
+
+  using ::abort;
+#if __cplusplus >= 201703L && defined(_GLIBCXX_HAVE_ALIGNED_ALLOC)
+  using ::aligned_alloc;
+#endif
+  using ::atexit;
+#if __cplusplus >= 201103L
+# ifdef _GLIBCXX_HAVE_AT_QUICK_EXIT
+  using ::at_quick_exit;
+# endif
+#endif
+  using ::atof;
+  using ::atoi;
+  using ::atol;
+  using ::bsearch;
+  using ::calloc;
+  using ::div;
+  using ::exit;
+  using ::free;
+  using ::getenv;
+  using ::labs;
+  using ::ldiv;
+  using ::malloc;
+#ifdef _GLIBCXX_HAVE_MBSTATE_T
+  using ::mblen;
+  using ::mbstowcs;
+  using ::mbtowc;
+#endif // _GLIBCXX_HAVE_MBSTATE_T
+  using ::qsort;
+#if __cplusplus >= 201103L
+# ifdef _GLIBCXX_HAVE_QUICK_EXIT
+  using ::quick_exit;
+# endif
+#endif
+  using ::rand;
+  using ::realloc;
+  using ::srand;
+  using ::strtod;
+  using ::strtol;
+  using ::strtoul;
+  using ::system;
+#ifdef _GLIBCXX_USE_WCHAR_T
+  using ::wcstombs;
+  using ::wctomb;
+#endif // _GLIBCXX_USE_WCHAR_T
+
+#ifndef __CORRECT_ISO_CPP_STDLIB_H_PROTO
+  inline ldiv_t
+  div(long __i, long __j) { return ldiv(__i, __j); }
+#endif
+
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#if _GLIBCXX_USE_C99_STDLIB
+
+#undef _Exit
+#undef llabs
+#undef lldiv
+#undef atoll
+#undef strtoll
+#undef strtoull
+#undef strtof
+#undef strtold
+
+namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+#if !_GLIBCXX_USE_C99_LONG_LONG_DYNAMIC
+  using ::lldiv_t;
+#endif
+#if _GLIBCXX_USE_C99_CHECK || _GLIBCXX_USE_C99_DYNAMIC
+  extern "C" void (_Exit)(int) throw () _GLIBCXX_NORETURN;
+#endif
+#if !_GLIBCXX_USE_C99_DYNAMIC
+  using ::_Exit;
+#endif
+
+#if !_GLIBCXX_USE_C99_LONG_LONG_DYNAMIC
+  using ::llabs;
+
+  inline lldiv_t
+  div(long long __n, long long __d)
+  { lldiv_t __q; __q.quot = __n / __d; __q.rem = __n % __d; return __q; }
+
+  using ::lldiv;
+#endif
+
+#if _GLIBCXX_USE_C99_LONG_LONG_CHECK || _GLIBCXX_USE_C99_LONG_LONG_DYNAMIC
+  extern "C" long long int (atoll)(const char *) throw ();
+  extern "C" long long int
+    (strtoll)(const char * __restrict, char ** __restrict, int) throw ();
+  extern "C" unsigned long long int
+    (strtoull)(const char * __restrict, char ** __restrict, int) throw ();
+#endif
+#if !_GLIBCXX_USE_C99_LONG_LONG_DYNAMIC
+  using ::atoll;
+  using ::strtoll;
+  using ::strtoull;
+#endif
+  using ::strtof;
+  using ::strtold;
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace __gnu_cxx
+
+namespace std
+{
+#if !_GLIBCXX_USE_C99_LONG_LONG_DYNAMIC
+  using ::__gnu_cxx::lldiv_t;
+#endif
+  using ::__gnu_cxx::_Exit;
+#if !_GLIBCXX_USE_C99_LONG_LONG_DYNAMIC
+  using ::__gnu_cxx::llabs;
+  using ::__gnu_cxx::div;
+  using ::__gnu_cxx::lldiv;
+#endif
+  using ::__gnu_cxx::atoll;
+  using ::__gnu_cxx::strtof;
+  using ::__gnu_cxx::strtoll;
+  using ::__gnu_cxx::strtoull;
+  using ::__gnu_cxx::strtold;
+} // namespace std
+
+#endif // _GLIBCXX_USE_C99_STDLIB
+
+} // extern "C++"
+
+#endif // !_GLIBCXX_HOSTED
+
+#endif
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@cstring b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@cstring
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--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@cstring
@@ -0,0 +1,126 @@
+// -*- C++ -*- forwarding header.
+
+// Copyright (C) 1997-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file cstring
+ *  This is a Standard C++ Library file.  You should @c \#include this file
+ *  in your programs, rather than any of the @a *.h implementation files.
+ *
+ *  This is the C++ version of the Standard C Library header @c string.h,
+ *  and its contents are (mostly) the same as that header, but are all
+ *  contained in the namespace @c std (except for names which are defined
+ *  as macros in C).
+ */
+
+//
+// ISO C++ 14882: 20.4.6  C library
+//
+
+#pragma GCC system_header
+
+#include <bits/c++config.h>
+#include <string.h>
+
+#ifndef _GLIBCXX_CSTRING
+#define _GLIBCXX_CSTRING 1
+
+// Get rid of those macros defined in <string.h> in lieu of real functions.
+#undef memchr
+#undef memcmp
+#undef memcpy
+#undef memmove
+#undef memset
+#undef strcat
+#undef strchr
+#undef strcmp
+#undef strcoll
+#undef strcpy
+#undef strcspn
+#undef strerror
+#undef strlen
+#undef strncat
+#undef strncmp
+#undef strncpy
+#undef strpbrk
+#undef strrchr
+#undef strspn
+#undef strstr
+#undef strtok
+#undef strxfrm
+
+extern "C++"
+{
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  using ::memchr;
+  using ::memcmp;
+  using ::memcpy;
+  using ::memmove;
+  using ::memset;
+  using ::strcat;
+  using ::strcmp;
+  using ::strcoll;
+  using ::strcpy;
+  using ::strcspn;
+  using ::strerror;
+  using ::strlen;
+  using ::strncat;
+  using ::strncmp;
+  using ::strncpy;
+  using ::strspn;
+  using ::strtok;
+  using ::strxfrm;
+  using ::strchr;
+  using ::strpbrk;
+  using ::strrchr;
+  using ::strstr;
+
+#ifndef __CORRECT_ISO_CPP_STRING_H_PROTO
+  inline void*
+  memchr(void* __s, int __c, size_t __n)
+  { return __builtin_memchr(__s, __c, __n); }
+
+  inline char*
+  strchr(char* __s, int __n)
+  { return __builtin_strchr(__s, __n); }
+
+  inline char*
+  strpbrk(char* __s1, const char* __s2)
+  { return __builtin_strpbrk(__s1, __s2); }
+
+  inline char*
+  strrchr(char* __s, int __n)
+  { return __builtin_strrchr(__s, __n); }
+
+  inline char*
+  strstr(char* __s1, const char* __s2)
+  { return __builtin_strstr(__s1, __s2); }
+#endif
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+} // extern "C++"
+
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@cstring.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@cstring.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@ctgmath b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@ctgmath
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@ctgmath
@@ -0,0 +1,44 @@
+// <ctgmath> -*- C++ -*-
+
+// Copyright (C) 2007-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file include/ctgmath
+ *  This is a Standard C++ Library header.
+ */
+
+#pragma GCC system_header
+
+#ifndef _GLIBCXX_CTGMATH
+#define _GLIBCXX_CTGMATH 1
+
+#if __cplusplus < 201103L
+#  include <bits/c++0x_warning.h>
+#else
+#  include <cmath>
+extern "C++" {
+#  include <complex>
+}
+#endif
+
+#endif 
+
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@@ -0,0 +1,84 @@
+// -*- C++ -*- forwarding header.
+
+// Copyright (C) 1997-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file include/ctime
+ *  This is a Standard C++ Library file.  You should @c \#include this file
+ *  in your programs, rather than any of the @a *.h implementation files.
+ *
+ *  This is the C++ version of the Standard C Library header @c time.h,
+ *  and its contents are (mostly) the same as that header, but are all
+ *  contained in the namespace @c std (except for names which are defined
+ *  as macros in C).
+ */
+
+//
+// ISO C++ 14882: 20.5  Date and time
+//
+
+#pragma GCC system_header
+
+#include <bits/c++config.h>
+#include <time.h>
+
+#ifndef _GLIBCXX_CTIME
+#define _GLIBCXX_CTIME 1
+
+// Get rid of those macros defined in <time.h> in lieu of real functions.
+#undef clock
+#undef difftime
+#undef mktime
+#undef time
+#undef asctime
+#undef ctime
+#undef gmtime
+#undef localtime
+#undef strftime
+
+namespace std
+{
+  using ::clock_t;
+  using ::time_t;
+  using ::tm;
+
+  using ::clock;
+  using ::difftime;
+  using ::mktime;
+  using ::time;
+  using ::asctime;
+  using ::ctime;
+  using ::gmtime;
+  using ::localtime;
+  using ::strftime;
+} // namespace
+
+#if __cplusplus >= 201703L && defined(_GLIBCXX_HAVE_TIMESPEC_GET)
+#undef timespec_get
+namespace std
+{
+  using ::timespec;
+  using ::timespec_get;
+} // namespace std
+#endif
+
+#endif
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@@ -0,0 +1,108 @@
+// -*- C++ -*- forwarding header.
+
+// Copyright (C) 2015-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file include/cuchar
+ *  This is a Standard C++ Library file.  You should @c \#include this file
+ *  in your programs, rather than any of the @a *.h implementation files.
+ *
+ *  This is the C++ version of the Standard C Library header @c uchar.h,
+ *  and its contents are (mostly) the same as that header, but are all
+ *  contained in the namespace @c std (except for names which are defined
+ *  as macros in C).
+ */
+
+//
+// ISO C++ 14882:2011 21.8
+//
+
+#ifndef _GLIBCXX_CUCHAR
+#define _GLIBCXX_CUCHAR 1
+
+#pragma GCC system_header
+
+#if __cplusplus < 201103L
+# include <bits/c++0x_warning.h>
+#else
+
+#include <bits/c++config.h>
+#include <cwchar>
+
+#if (_GLIBCXX_USE_C11_UCHAR_CXX11 \
+     || (_GLIBCXX_USE_CHAR8_T \
+	 && (_GLIBCXX_USE_UCHAR_C8RTOMB_MBRTOC8_FCHAR8_T \
+	     || (__cplusplus >= 202002 \
+		 && _GLIBCXX_USE_UCHAR_C8RTOMB_MBRTOC8_CXX20))))
+
+#include <uchar.h>
+
+#endif
+
+
+// Support for mbrtoc8 and c8rtomb is conditioned on support by the C library.
+#if (_GLIBCXX_USE_CHAR8_T \
+     && (_GLIBCXX_USE_UCHAR_C8RTOMB_MBRTOC8_FCHAR8_T \
+	 || (__cplusplus >= 202002 \
+	     && _GLIBCXX_USE_UCHAR_C8RTOMB_MBRTOC8_CXX20)))
+
+#undef mbrtoc8
+#undef c8rtomb
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  using ::mbrtoc8;
+  using ::c8rtomb;
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif // _GLIBCXX_USE_CHAR8_T
+
+
+#if _GLIBCXX_USE_C11_UCHAR_CXX11
+
+// Get rid of those macros defined in <uchar.h> in lieu of real functions.
+#undef mbrtoc16
+#undef c16rtomb
+#undef mbrtoc32
+#undef c32rtomb
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  using ::mbrtoc16;
+  using ::c16rtomb;
+  using ::mbrtoc32;
+  using ::c32rtomb;
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif // _GLIBCXX_USE_C11_UCHAR_CXX11
+
+#endif // C++11
+
+#endif // _GLIBCXX_CUCHAR
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@cwchar b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@cwchar
new file mode 100644
index 0000000000000000000000000000000000000000..5ad870b9677d251830558e50c1519e64fc7def84
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@cwchar
@@ -0,0 +1,306 @@
+// -*- C++ -*- forwarding header.
+
+// Copyright (C) 1997-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file include/cwchar
+ *  This is a Standard C++ Library file.  You should @c \#include this file
+ *  in your programs, rather than any of the @a *.h implementation files.
+ *
+ *  This is the C++ version of the Standard C Library header @c wchar.h,
+ *  and its contents are (mostly) the same as that header, but are all
+ *  contained in the namespace @c std (except for names which are defined
+ *  as macros in C).
+ */
+
+//
+// ISO C++ 14882: 21.4
+//
+
+#pragma GCC system_header
+
+#include <bits/c++config.h>
+
+#if _GLIBCXX_HAVE_WCHAR_H
+#include <wchar.h>
+#endif
+
+#ifndef _GLIBCXX_CWCHAR
+#define _GLIBCXX_CWCHAR 1
+
+// Need to do a bit of trickery here with mbstate_t as char_traits
+// assumes it is in wchar.h, regardless of wchar_t specializations.
+#ifndef _GLIBCXX_HAVE_MBSTATE_T
+extern "C"
+{
+  typedef struct
+  {
+    int __fill[6];
+  } mbstate_t;
+}
+#endif
+
+namespace std
+{
+  using ::mbstate_t;
+} // namespace std
+
+// Get rid of those macros defined in <wchar.h> in lieu of real functions.
+#undef btowc
+#undef fgetwc
+#undef fgetws
+#undef fputwc
+#undef fputws
+#undef fwide
+#undef fwprintf
+#undef fwscanf
+#undef getwc
+#undef getwchar
+#undef mbrlen
+#undef mbrtowc
+#undef mbsinit
+#undef mbsrtowcs
+#undef putwc
+#undef putwchar
+#undef swprintf
+#undef swscanf
+#undef ungetwc
+#undef vfwprintf
+#if _GLIBCXX_HAVE_VFWSCANF
+# undef vfwscanf
+#endif
+#undef vswprintf
+#if _GLIBCXX_HAVE_VSWSCANF
+# undef vswscanf
+#endif
+#undef vwprintf
+#if _GLIBCXX_HAVE_VWSCANF
+# undef vwscanf
+#endif
+#undef wcrtomb
+#undef wcscat
+#undef wcschr
+#undef wcscmp
+#undef wcscoll
+#undef wcscpy
+#undef wcscspn
+#undef wcsftime
+#undef wcslen
+#undef wcsncat
+#undef wcsncmp
+#undef wcsncpy
+#undef wcspbrk
+#undef wcsrchr
+#undef wcsrtombs
+#undef wcsspn
+#undef wcsstr
+#undef wcstod
+#if _GLIBCXX_HAVE_WCSTOF
+# undef wcstof
+#endif
+#undef wcstok
+#undef wcstol
+#undef wcstoul
+#undef wcsxfrm
+#undef wctob
+#undef wmemchr
+#undef wmemcmp
+#undef wmemcpy
+#undef wmemmove
+#undef wmemset
+#undef wprintf
+#undef wscanf
+
+#if _GLIBCXX_USE_WCHAR_T
+
+extern "C++"
+{
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  using ::wint_t;
+
+  using ::btowc;
+  using ::fgetwc;
+  using ::fgetws;
+  using ::fputwc;
+  using ::fputws;
+  using ::fwide;
+  using ::fwprintf;
+  using ::fwscanf;
+  using ::getwc;
+  using ::getwchar;
+  using ::mbrlen;
+  using ::mbrtowc;
+  using ::mbsinit;
+  using ::mbsrtowcs;
+  using ::putwc;
+  using ::putwchar;
+#ifndef _GLIBCXX_HAVE_BROKEN_VSWPRINTF
+  using ::swprintf;
+#endif
+  using ::swscanf;
+  using ::ungetwc;
+  using ::vfwprintf;
+#if _GLIBCXX_HAVE_VFWSCANF
+  using ::vfwscanf;
+#endif
+#ifndef _GLIBCXX_HAVE_BROKEN_VSWPRINTF
+  using ::vswprintf;
+#endif
+#if _GLIBCXX_HAVE_VSWSCANF
+  using ::vswscanf;
+#endif
+  using ::vwprintf;
+#if _GLIBCXX_HAVE_VWSCANF
+  using ::vwscanf;
+#endif
+  using ::wcrtomb;
+  using ::wcscat;
+  using ::wcscmp;
+  using ::wcscoll;
+  using ::wcscpy;
+  using ::wcscspn;
+  using ::wcsftime;
+  using ::wcslen;
+  using ::wcsncat;
+  using ::wcsncmp;
+  using ::wcsncpy;
+  using ::wcsrtombs;
+  using ::wcsspn;
+  using ::wcstod;
+#if _GLIBCXX_HAVE_WCSTOF
+  using ::wcstof;
+#endif
+  using ::wcstok;
+  using ::wcstol;
+  using ::wcstoul;
+  using ::wcsxfrm;
+  using ::wctob;
+  using ::wmemcmp;
+  using ::wmemcpy;
+  using ::wmemmove;
+  using ::wmemset;
+  using ::wprintf;
+  using ::wscanf;
+  using ::wcschr;
+  using ::wcspbrk;
+  using ::wcsrchr;
+  using ::wcsstr;
+  using ::wmemchr;
+
+#ifndef __CORRECT_ISO_CPP_WCHAR_H_PROTO
+  inline wchar_t*
+  wcschr(wchar_t* __p, wchar_t __c)
+  { return wcschr(const_cast<const wchar_t*>(__p), __c); }
+
+  inline wchar_t*
+  wcspbrk(wchar_t* __s1, const wchar_t* __s2)
+  { return wcspbrk(const_cast<const wchar_t*>(__s1), __s2); }
+
+  inline wchar_t*
+  wcsrchr(wchar_t* __p, wchar_t __c)
+  { return wcsrchr(const_cast<const wchar_t*>(__p), __c); }
+
+  inline wchar_t*
+  wcsstr(wchar_t* __s1, const wchar_t* __s2)
+  { return wcsstr(const_cast<const wchar_t*>(__s1), __s2); }
+
+  inline wchar_t*
+  wmemchr(wchar_t* __p, wchar_t __c, size_t __n)
+  { return wmemchr(const_cast<const wchar_t*>(__p), __c, __n); }
+#endif
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+} // extern "C++"
+
+#if _GLIBCXX_USE_C99_WCHAR
+
+#undef wcstold
+#undef wcstoll
+#undef wcstoull
+
+namespace __gnu_cxx
+{
+#if _GLIBCXX_USE_C99_CHECK || _GLIBCXX_USE_C99_DYNAMIC
+  extern "C" long double
+    (wcstold)(const wchar_t * __restrict, wchar_t ** __restrict) throw ();
+#endif
+#if !_GLIBCXX_USE_C99_DYNAMIC
+  using ::wcstold;
+#endif
+#if _GLIBCXX_USE_C99_LONG_LONG_CHECK || _GLIBCXX_USE_C99_LONG_LONG_DYNAMIC
+  extern "C" long long int
+    (wcstoll)(const wchar_t * __restrict, wchar_t ** __restrict, int) throw ();
+  extern "C" unsigned long long int
+    (wcstoull)(const wchar_t * __restrict, wchar_t ** __restrict, int) throw ();
+#endif
+#if !_GLIBCXX_USE_C99_LONG_LONG_DYNAMIC
+  using ::wcstoll;
+  using ::wcstoull;
+#endif
+} // namespace __gnu_cxx
+
+namespace std
+{
+  using ::__gnu_cxx::wcstold;
+  using ::__gnu_cxx::wcstoll;
+  using ::__gnu_cxx::wcstoull;
+} // namespace
+
+#endif
+
+#endif //_GLIBCXX_USE_WCHAR_T
+
+#if __cplusplus >= 201103L
+
+#ifdef _GLIBCXX_USE_WCHAR_T
+
+namespace std
+{
+#if _GLIBCXX_HAVE_WCSTOF
+  using std::wcstof;
+#endif
+#if _GLIBCXX_HAVE_VFWSCANF
+  using std::vfwscanf;
+#endif
+#if _GLIBCXX_HAVE_VSWSCANF
+  using std::vswscanf;
+#endif
+#if _GLIBCXX_HAVE_VWSCANF
+  using std::vwscanf;
+#endif
+
+#if _GLIBCXX_USE_C99_WCHAR
+  using std::wcstold;
+  using std::wcstoll;
+  using std::wcstoull;
+#endif
+} // namespace
+
+#endif // _GLIBCXX_USE_WCHAR_T
+
+#endif // C++11
+
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@cwchar.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@cwchar.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@cwctype b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@cwctype
new file mode 100644
index 0000000000000000000000000000000000000000..d80ff72b2020a898f5268f6a2517c38b5048f4d9
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@cwctype
@@ -0,0 +1,110 @@
+// -*- C++ -*- forwarding header.
+
+// Copyright (C) 1997-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file include/cwctype
+ *  This is a Standard C++ Library file.  You should @c \#include this file
+ *  in your programs, rather than any of the @a *.h implementation files.
+ *
+ *  This is the C++ version of the Standard C Library header @c wctype.h,
+ *  and its contents are (mostly) the same as that header, but are all
+ *  contained in the namespace @c std (except for names which are defined
+ *  as macros in C).
+ */
+
+//
+// ISO C++ 14882: <cwctype>
+//
+
+#pragma GCC system_header
+
+#include <bits/c++config.h>
+
+#if _GLIBCXX_HAVE_WCTYPE_H
+
+#if __GLIBC__ == 2 && __GLIBC_MINOR__ < 10
+// Work around glibc BZ 9694
+#include <stddef.h>
+#endif
+
+#include <wctype.h>
+#endif // _GLIBCXX_HAVE_WCTYPE_H
+
+#ifndef _GLIBCXX_CWCTYPE
+#define _GLIBCXX_CWCTYPE 1
+
+// Get rid of those macros defined in <wctype.h> in lieu of real functions.
+#undef iswalnum
+#undef iswalpha
+#if _GLIBCXX_HAVE_ISWBLANK
+# undef iswblank
+#endif
+#undef iswcntrl
+#undef iswctype
+#undef iswdigit
+#undef iswgraph
+#undef iswlower
+#undef iswprint
+#undef iswpunct
+#undef iswspace
+#undef iswupper
+#undef iswxdigit
+#undef towctrans
+#undef towlower
+#undef towupper
+#undef wctrans
+#undef wctype
+
+#if _GLIBCXX_USE_WCHAR_T
+
+namespace std
+{
+  using ::wctrans_t;
+  using ::wctype_t;
+  using ::wint_t;
+
+  using ::iswalnum;
+  using ::iswalpha;
+#if _GLIBCXX_HAVE_ISWBLANK
+  using ::iswblank;
+#endif
+  using ::iswcntrl;
+  using ::iswctype;
+  using ::iswdigit;
+  using ::iswgraph;
+  using ::iswlower;
+  using ::iswprint;
+  using ::iswpunct;
+  using ::iswspace;
+  using ::iswupper;
+  using ::iswxdigit;
+  using ::towctrans;
+  using ::towlower;
+  using ::towupper;
+  using ::wctrans;
+  using ::wctype;
+} // namespace
+
+#endif //_GLIBCXX_USE_WCHAR_T
+
+#endif // _GLIBCXX_CWCTYPE
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@cwctype.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@cwctype.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@debug@assertions.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@debug@assertions.h
new file mode 100644
index 0000000000000000000000000000000000000000..57c0ab2c3cf6d714ba41fed1b1107745494ba5e2
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@debug@assertions.h
@@ -0,0 +1,70 @@
+// Debugging support implementation -*- C++ -*-
+
+// Copyright (C) 2003-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file debug/assertions.h
+ *  This file is a GNU debug extension to the Standard C++ Library.
+ */
+
+#ifndef _GLIBCXX_DEBUG_ASSERTIONS_H
+#define _GLIBCXX_DEBUG_ASSERTIONS_H 1
+
+#include <bits/c++config.h>
+
+#ifndef _GLIBCXX_DEBUG
+
+# define _GLIBCXX_DEBUG_ASSERT(_Condition)
+# define _GLIBCXX_DEBUG_PEDASSERT(_Condition)
+# define _GLIBCXX_DEBUG_ONLY(_Statement)
+
+#endif
+
+#ifndef _GLIBCXX_ASSERTIONS
+# define __glibcxx_requires_non_empty_range(_First,_Last)
+# define __glibcxx_requires_nonempty()
+# define __glibcxx_requires_subscript(_N)
+#else
+
+// Verify that [_First, _Last) forms a non-empty iterator range.
+# define __glibcxx_requires_non_empty_range(_First,_Last)	\
+  __glibcxx_assert(_First != _Last)
+# define __glibcxx_requires_subscript(_N)	\
+  __glibcxx_assert(_N < this->size())
+// Verify that the container is nonempty
+# define __glibcxx_requires_nonempty()		\
+  __glibcxx_assert(!this->empty())
+#endif
+
+#ifdef _GLIBCXX_DEBUG
+# define _GLIBCXX_DEBUG_ASSERT(_Condition) __glibcxx_assert(_Condition)
+
+# ifdef _GLIBCXX_DEBUG_PEDANTIC
+#  define _GLIBCXX_DEBUG_PEDASSERT(_Condition) _GLIBCXX_DEBUG_ASSERT(_Condition)
+# else
+#  define _GLIBCXX_DEBUG_PEDASSERT(_Condition)
+# endif
+
+# define _GLIBCXX_DEBUG_ONLY(_Statement) _Statement
+#endif
+
+#endif // _GLIBCXX_DEBUG_ASSERTIONS
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@debug@debug.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@debug@debug.h
new file mode 100644
index 0000000000000000000000000000000000000000..d3cdfbc044c360d51246dea6be2ad841a7a4dcde
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@debug@debug.h
@@ -0,0 +1,137 @@
+// Debugging support implementation -*- C++ -*-
+
+// Copyright (C) 2003-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file debug/debug.h
+ *  This file is a GNU debug extension to the Standard C++ Library.
+ */
+
+#ifndef _GLIBCXX_DEBUG_MACRO_SWITCH_H
+#define _GLIBCXX_DEBUG_MACRO_SWITCH_H 1
+
+/** Macros and namespaces used by the implementation outside of debug
+ *  wrappers to verify certain properties. The __glibcxx_requires_xxx
+ *  macros are merely wrappers around the __glibcxx_check_xxx wrappers
+ *  when we are compiling with debug mode, but disappear when we are
+ *  in release mode so that there is no checking performed in, e.g.,
+ *  the standard library algorithms.
+*/
+
+#include <debug/assertions.h>
+
+// Debug mode namespaces.
+
+/**
+ * @namespace std::__debug
+ * @brief GNU debug code, replaces standard behavior with debug behavior.
+ */
+namespace std
+{ 
+  namespace __debug { } 
+}
+
+/** @namespace __gnu_debug
+ *  @brief GNU debug classes for public use.
+*/
+namespace __gnu_debug
+{
+  using namespace std::__debug;
+
+  template<typename _Ite, typename _Seq, typename _Cat>
+    struct _Safe_iterator;
+}
+
+#ifndef _GLIBCXX_DEBUG
+
+# define __glibcxx_requires_cond(_Cond,_Msg)
+# define __glibcxx_requires_valid_range(_First,_Last)
+# define __glibcxx_requires_can_increment(_First,_Size)
+# define __glibcxx_requires_can_increment_range(_First1,_Last1,_First2)
+# define __glibcxx_requires_can_decrement_range(_First1,_Last1,_First2)
+# define __glibcxx_requires_sorted(_First,_Last)
+# define __glibcxx_requires_sorted_pred(_First,_Last,_Pred)
+# define __glibcxx_requires_sorted_set(_First1,_Last1,_First2)
+# define __glibcxx_requires_sorted_set_pred(_First1,_Last1,_First2,_Pred)
+# define __glibcxx_requires_partitioned_lower(_First,_Last,_Value)
+# define __glibcxx_requires_partitioned_upper(_First,_Last,_Value)
+# define __glibcxx_requires_partitioned_lower_pred(_First,_Last,_Value,_Pred)
+# define __glibcxx_requires_partitioned_upper_pred(_First,_Last,_Value,_Pred)
+# define __glibcxx_requires_heap(_First,_Last)
+# define __glibcxx_requires_heap_pred(_First,_Last,_Pred)
+# define __glibcxx_requires_string(_String)
+# define __glibcxx_requires_string_len(_String,_Len)
+# define __glibcxx_requires_irreflexive(_First,_Last)
+# define __glibcxx_requires_irreflexive2(_First,_Last)
+# define __glibcxx_requires_irreflexive_pred(_First,_Last,_Pred)
+# define __glibcxx_requires_irreflexive_pred2(_First,_Last,_Pred)
+
+#else
+
+# include <debug/macros.h>
+
+# define __glibcxx_requires_cond(_Cond,_Msg) _GLIBCXX_DEBUG_VERIFY(_Cond,_Msg)
+# define __glibcxx_requires_valid_range(_First,_Last)	\
+  __glibcxx_check_valid_range(_First,_Last)
+# define __glibcxx_requires_can_increment(_First,_Size)	\
+  __glibcxx_check_can_increment(_First,_Size)
+# define __glibcxx_requires_can_increment_range(_First1,_Last1,_First2)	\
+  __glibcxx_check_can_increment_range(_First1,_Last1,_First2)
+# define __glibcxx_requires_can_decrement_range(_First1,_Last1,_First2)	\
+  __glibcxx_check_can_decrement_range(_First1,_Last1,_First2)
+# define __glibcxx_requires_sorted(_First,_Last)	\
+  __glibcxx_check_sorted(_First,_Last)
+# define __glibcxx_requires_sorted_pred(_First,_Last,_Pred)	\
+  __glibcxx_check_sorted_pred(_First,_Last,_Pred)
+# define __glibcxx_requires_sorted_set(_First1,_Last1,_First2)	\
+  __glibcxx_check_sorted_set(_First1,_Last1,_First2)
+# define __glibcxx_requires_sorted_set_pred(_First1,_Last1,_First2,_Pred) \
+  __glibcxx_check_sorted_set_pred(_First1,_Last1,_First2,_Pred)
+# define __glibcxx_requires_partitioned_lower(_First,_Last,_Value)	\
+  __glibcxx_check_partitioned_lower(_First,_Last,_Value)
+# define __glibcxx_requires_partitioned_upper(_First,_Last,_Value)	\
+  __glibcxx_check_partitioned_upper(_First,_Last,_Value)
+# define __glibcxx_requires_partitioned_lower_pred(_First,_Last,_Value,_Pred) \
+  __glibcxx_check_partitioned_lower_pred(_First,_Last,_Value,_Pred)
+# define __glibcxx_requires_partitioned_upper_pred(_First,_Last,_Value,_Pred) \
+  __glibcxx_check_partitioned_upper_pred(_First,_Last,_Value,_Pred)
+# define __glibcxx_requires_heap(_First,_Last)	\
+  __glibcxx_check_heap(_First,_Last)
+# define __glibcxx_requires_heap_pred(_First,_Last,_Pred)	\
+  __glibcxx_check_heap_pred(_First,_Last,_Pred)
+# define __glibcxx_requires_string(_String) __glibcxx_check_string(_String)
+# define __glibcxx_requires_string_len(_String,_Len)	\
+  __glibcxx_check_string_len(_String,_Len)
+# define __glibcxx_requires_irreflexive(_First,_Last)	\
+  __glibcxx_check_irreflexive(_First,_Last)
+# define __glibcxx_requires_irreflexive2(_First,_Last)	\
+  __glibcxx_check_irreflexive2(_First,_Last)
+# define __glibcxx_requires_irreflexive_pred(_First,_Last,_Pred)	\
+  __glibcxx_check_irreflexive_pred(_First,_Last,_Pred)
+# define __glibcxx_requires_irreflexive_pred2(_First,_Last,_Pred)	\
+  __glibcxx_check_irreflexive_pred2(_First,_Last,_Pred)
+
+# include <debug/functions.h>
+
+#endif
+
+#endif // _GLIBCXX_DEBUG_MACRO_SWITCH_H
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@@ -0,0 +1,137 @@
+// <deque> -*- C++ -*-
+
+// Copyright (C) 2001-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/*
+ *
+ * Copyright (c) 1994
+ * Hewlett-Packard Company
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Hewlett-Packard Company makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ *
+ *
+ * Copyright (c) 1997
+ * Silicon Graphics Computer Systems, Inc.
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Silicon Graphics makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ */
+
+/** @file include/deque
+ *  This is a Standard C++ Library header.
+ */
+
+#ifndef _GLIBCXX_DEQUE
+#define _GLIBCXX_DEQUE 1
+
+#pragma GCC system_header
+
+#include <bits/stl_algobase.h>
+#include <bits/allocator.h>
+#include <bits/stl_construct.h>
+#include <bits/stl_uninitialized.h>
+#include <bits/stl_deque.h>
+#include <bits/refwrap.h>
+#include <bits/range_access.h>
+#include <bits/deque.tcc>
+
+#ifdef _GLIBCXX_DEBUG
+# include <debug/deque>
+#endif
+
+#if __cplusplus >= 201703L
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+  namespace pmr
+  {
+    template<typename _Tp> class polymorphic_allocator;
+    template<typename _Tp>
+      using deque = std::deque<_Tp, polymorphic_allocator<_Tp>>;
+  } // namespace pmr
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+#endif // C++17
+
+#if __cplusplus > 201703L
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+#define __cpp_lib_erase_if 202002L
+
+  template<typename _Tp, typename _Alloc, typename _Predicate>
+    inline typename deque<_Tp, _Alloc>::size_type
+    erase_if(deque<_Tp, _Alloc>& __cont, _Predicate __pred)
+    {
+      using namespace __gnu_cxx;
+      _GLIBCXX_STD_C::deque<_Tp, _Alloc>& __ucont = __cont;
+      const auto __osz = __cont.size();
+      const auto __end = __ucont.end();
+      auto __removed = std::__remove_if(__ucont.begin(), __end,
+					__ops::__pred_iter(std::ref(__pred)));
+      if (__removed != __end)
+	{
+	  __cont.erase(__niter_wrap(__cont.begin(), __removed),
+		       __cont.end());
+	  return __osz - __cont.size();
+	}
+
+      return 0;
+    }
+
+  template<typename _Tp, typename _Alloc, typename _Up>
+    inline typename deque<_Tp, _Alloc>::size_type
+    erase(deque<_Tp, _Alloc>& __cont, const _Up& __value)
+    {
+      using namespace __gnu_cxx;
+      _GLIBCXX_STD_C::deque<_Tp, _Alloc>& __ucont = __cont;
+      const auto __osz = __cont.size();
+      const auto __end = __ucont.end();
+      auto __removed = std::__remove_if(__ucont.begin(), __end,
+					__ops::__iter_equals_val(__value));
+      if (__removed != __end)
+	{
+	  __cont.erase(__niter_wrap(__cont.begin(), __removed),
+		       __cont.end());
+	  return __osz - __cont.size();
+	}
+
+      return 0;
+    }
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+#endif // C++20
+
+#endif /* _GLIBCXX_DEQUE */
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@@ -0,0 +1,172 @@
+// Exception Handling support header for -*- C++ -*-
+
+// Copyright (C) 1995-2022 Free Software Foundation, Inc.
+//
+// This file is part of GCC.
+//
+// GCC is free software; you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation; either version 3, or (at your option)
+// any later version.
+//
+// GCC is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file exception
+ *  This is a Standard C++ Library header.
+ */
+
+#ifndef __EXCEPTION__
+#define __EXCEPTION__
+
+#pragma GCC system_header
+
+#pragma GCC visibility push(default)
+
+#include <bits/c++config.h>
+#include <bits/exception.h>
+
+extern "C++" {
+
+namespace std
+{
+  /** @addtogroup exceptions
+   *  @{
+   */
+
+  /** If an %exception is thrown which is not listed in a function's
+   *  %exception specification, one of these may be thrown.
+   *
+   *  @ingroup exceptions
+   */
+  class bad_exception : public exception
+  {
+  public:
+    bad_exception() _GLIBCXX_USE_NOEXCEPT { }
+
+    // This declaration is not useless:
+    // http://gcc.gnu.org/onlinedocs/gcc-3.0.2/gcc_6.html#SEC118
+    virtual ~bad_exception() _GLIBCXX_TXN_SAFE_DYN _GLIBCXX_USE_NOEXCEPT;
+
+    // See comment in eh_exception.cc.
+    virtual const char*
+    what() const _GLIBCXX_TXN_SAFE_DYN _GLIBCXX_USE_NOEXCEPT;
+  };
+
+  /// If you write a replacement %terminate handler, it must be of this type.
+  typedef void (*terminate_handler) ();
+
+  /// Takes a new handler function as an argument, returns the old function.
+  terminate_handler set_terminate(terminate_handler) _GLIBCXX_USE_NOEXCEPT;
+
+#if __cplusplus >= 201103L
+  /// Return the current terminate handler.
+  terminate_handler get_terminate() noexcept;
+#endif
+
+  /** The runtime will call this function if %exception handling must be
+   *  abandoned for any reason.  It can also be called by the user.  */
+  void terminate() _GLIBCXX_USE_NOEXCEPT __attribute__ ((__noreturn__));
+
+#if __cplusplus < 201703L || (__cplusplus <= 202002L && _GLIBCXX_USE_DEPRECATED)
+  /// If you write a replacement %unexpected handler, it must be of this type.
+  typedef void (*_GLIBCXX11_DEPRECATED unexpected_handler) ();
+
+  /** Takes a new handler function as an argument, returns the old function.
+   *
+   * @deprecated Removed from the C++ standard in C++17
+   */
+  _GLIBCXX11_DEPRECATED
+  unexpected_handler set_unexpected(unexpected_handler) _GLIBCXX_USE_NOEXCEPT;
+
+#if __cplusplus >= 201103L
+  /** Return the current unexpected handler.
+   *
+   * @since C++11
+   * @deprecated Removed from the C++ standard in C++17
+   */
+  _GLIBCXX11_DEPRECATED
+  unexpected_handler get_unexpected() noexcept;
+#endif
+
+  /** The runtime will call this function if an %exception is thrown which
+   *  violates the function's %exception specification.
+   *
+   * @deprecated Removed from the C++ standard in C++17
+   */
+  _GLIBCXX11_DEPRECATED
+  void unexpected() __attribute__ ((__noreturn__));
+#endif
+
+  /** [18.6.4]/1:  'Returns true after completing evaluation of a
+   *  throw-expression until either completing initialization of the
+   *  exception-declaration in the matching handler or entering `unexpected()`
+   *  due to the throw; or after entering `terminate()` for any reason
+   *  other than an explicit call to `terminate()`.  [Note: This includes
+   *  stack unwinding [15.2].  end note]'
+   *
+   *  2: 'When `uncaught_exception()` is true, throwing an
+   *  %exception can result in a call of 1terminate()`
+   *  (15.5.1).'
+   */
+  _GLIBCXX17_DEPRECATED_SUGGEST("std::uncaught_exceptions()")
+  bool uncaught_exception() _GLIBCXX_USE_NOEXCEPT __attribute__ ((__pure__));
+
+#if __cplusplus >= 201703L || !defined(__STRICT_ANSI__) // c++17 or gnu++98
+#define __cpp_lib_uncaught_exceptions 201411L
+  /** The number of uncaught exceptions.
+   *  @since C++17, or any non-strict mode, e.g. `-std=gnu++98`
+   *  @see uncaught_exception()
+   */
+  int uncaught_exceptions() _GLIBCXX_USE_NOEXCEPT __attribute__ ((__pure__));
+#endif
+
+  /// @} group exceptions
+} // namespace std
+
+namespace __gnu_cxx
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /**
+   *  @brief A replacement for the standard terminate_handler which
+   *  prints more information about the terminating exception (if any)
+   *  on stderr.
+   *
+   *  @ingroup exceptions
+   *
+   *  Call
+   *   @code
+   *     std::set_terminate(__gnu_cxx::__verbose_terminate_handler)
+   *   @endcode
+   *  to use.  For more info, see
+   *  http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt02ch06s02.html
+   *
+   *  In 3.4 and later, this is on by default.
+   */
+  void __verbose_terminate_handler();
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+} // extern "C++"
+
+#pragma GCC visibility pop
+
+#if (__cplusplus >= 201103L)
+#include <bits/exception_ptr.h>
+#include <bits/nested_exception.h>
+#endif
+
+#endif
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@@ -0,0 +1,125 @@
+// Aligned memory buffer -*- C++ -*-
+
+// Copyright (C) 2013-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file ext/aligned_buffer.h
+ *  This file is a GNU extension to the Standard C++ Library.
+ */
+
+#ifndef _ALIGNED_BUFFER_H
+#define _ALIGNED_BUFFER_H 1
+
+#pragma GCC system_header
+
+#if __cplusplus >= 201103L
+# include <type_traits>
+#else
+# include <bits/c++0x_warning.h>
+#endif
+
+namespace __gnu_cxx
+{
+  // A utility type containing a POD object that can hold an object of type
+  // _Tp initialized via placement new or allocator_traits::construct.
+  // Intended for use as a data member subobject, use __aligned_buffer for
+  // complete objects.
+  template<typename _Tp>
+    struct __aligned_membuf
+    {
+      // Target macro ADJUST_FIELD_ALIGN can produce different alignment for
+      // types when used as class members. __aligned_membuf is intended
+      // for use as a class member, so align the buffer as for a class member.
+      // Since GCC 8 we could just use alignof(_Tp) instead, but older
+      // versions of non-GNU compilers might still need this trick.
+      struct _Tp2 { _Tp _M_t; };
+
+      alignas(__alignof__(_Tp2::_M_t)) unsigned char _M_storage[sizeof(_Tp)];
+
+      __aligned_membuf() = default;
+
+      // Can be used to avoid value-initialization zeroing _M_storage.
+      __aligned_membuf(std::nullptr_t) { }
+
+      void*
+      _M_addr() noexcept
+      { return static_cast<void*>(&_M_storage); }
+
+      const void*
+      _M_addr() const noexcept
+      { return static_cast<const void*>(&_M_storage); }
+
+      _Tp*
+      _M_ptr() noexcept
+      { return static_cast<_Tp*>(_M_addr()); }
+
+      const _Tp*
+      _M_ptr() const noexcept
+      { return static_cast<const _Tp*>(_M_addr()); }
+    };
+
+#if _GLIBCXX_INLINE_VERSION
+  template<typename _Tp>
+    using __aligned_buffer = __aligned_membuf<_Tp>;
+#else
+  // Similar to __aligned_membuf but aligned for complete objects, not members.
+  // This type is used in <forward_list>, <future>, <bits/shared_ptr_base.h>
+  // and <bits/hashtable_policy.h>, but ideally they would use __aligned_membuf
+  // instead, as it has smaller size for some types on some targets.
+  // This type is still used to avoid an ABI change.
+  template<typename _Tp>
+    struct __aligned_buffer
+    : std::aligned_storage<sizeof(_Tp), __alignof__(_Tp)>
+    {
+      typename
+	std::aligned_storage<sizeof(_Tp), __alignof__(_Tp)>::type _M_storage;
+
+      __aligned_buffer() = default;
+
+      // Can be used to avoid value-initialization
+      __aligned_buffer(std::nullptr_t) { }
+
+      void*
+      _M_addr() noexcept
+      {
+        return static_cast<void*>(&_M_storage);
+      }
+
+      const void*
+      _M_addr() const noexcept
+      {
+        return static_cast<const void*>(&_M_storage);
+      }
+
+      _Tp*
+      _M_ptr() noexcept
+      { return static_cast<_Tp*>(_M_addr()); }
+
+      const _Tp*
+      _M_ptr() const noexcept
+      { return static_cast<const _Tp*>(_M_addr()); }
+    };
+#endif
+
+} // namespace
+
+#endif /* _ALIGNED_BUFFER_H */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@ext@aligned_buffer.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@ext@aligned_buffer.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@ext@alloc_traits.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@ext@alloc_traits.h
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--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@ext@alloc_traits.h
@@ -0,0 +1,171 @@
+// Allocator traits -*- C++ -*-
+
+// Copyright (C) 2011-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file ext/alloc_traits.h
+ *  This file is a GNU extension to the Standard C++ Library.
+ */
+
+#ifndef _EXT_ALLOC_TRAITS_H
+#define _EXT_ALLOC_TRAITS_H 1
+
+#pragma GCC system_header
+
+# include <bits/alloc_traits.h>
+#if __cplusplus < 201103L
+# include <bits/allocator.h>  // for __alloc_swap
+#endif
+
+namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+/**
+ * @brief  Uniform interface to C++98 and C++11 allocators.
+ * @ingroup allocators
+*/
+template<typename _Alloc, typename = typename _Alloc::value_type>
+  struct __alloc_traits
+#if __cplusplus >= 201103L
+  : std::allocator_traits<_Alloc>
+#endif
+  {
+    typedef _Alloc allocator_type;
+#if __cplusplus >= 201103L
+    typedef std::allocator_traits<_Alloc>           _Base_type;
+    typedef typename _Base_type::value_type         value_type;
+    typedef typename _Base_type::pointer            pointer;
+    typedef typename _Base_type::const_pointer      const_pointer;
+    typedef typename _Base_type::size_type          size_type;
+    typedef typename _Base_type::difference_type    difference_type;
+    // C++11 allocators do not define reference or const_reference
+    typedef value_type&                             reference;
+    typedef const value_type&                       const_reference;
+    using _Base_type::allocate;
+    using _Base_type::deallocate;
+    using _Base_type::construct;
+    using _Base_type::destroy;
+    using _Base_type::max_size;
+
+  private:
+    template<typename _Ptr>
+      using __is_custom_pointer
+	= std::__and_<std::is_same<pointer, _Ptr>,
+		      std::__not_<std::is_pointer<_Ptr>>>;
+
+  public:
+    // overload construct for non-standard pointer types
+    template<typename _Ptr, typename... _Args>
+      static _GLIBCXX14_CONSTEXPR
+      std::__enable_if_t<__is_custom_pointer<_Ptr>::value>
+      construct(_Alloc& __a, _Ptr __p, _Args&&... __args)
+      noexcept(noexcept(_Base_type::construct(__a, std::__to_address(__p),
+					      std::forward<_Args>(__args)...)))
+      {
+	_Base_type::construct(__a, std::__to_address(__p),
+			      std::forward<_Args>(__args)...);
+      }
+
+    // overload destroy for non-standard pointer types
+    template<typename _Ptr>
+      static _GLIBCXX14_CONSTEXPR
+      std::__enable_if_t<__is_custom_pointer<_Ptr>::value>
+      destroy(_Alloc& __a, _Ptr __p)
+      noexcept(noexcept(_Base_type::destroy(__a, std::__to_address(__p))))
+      { _Base_type::destroy(__a, std::__to_address(__p)); }
+
+    static constexpr _Alloc _S_select_on_copy(const _Alloc& __a)
+    { return _Base_type::select_on_container_copy_construction(__a); }
+
+    static _GLIBCXX14_CONSTEXPR void _S_on_swap(_Alloc& __a, _Alloc& __b)
+    { std::__alloc_on_swap(__a, __b); }
+
+    static constexpr bool _S_propagate_on_copy_assign()
+    { return _Base_type::propagate_on_container_copy_assignment::value; }
+
+    static constexpr bool _S_propagate_on_move_assign()
+    { return _Base_type::propagate_on_container_move_assignment::value; }
+
+    static constexpr bool _S_propagate_on_swap()
+    { return _Base_type::propagate_on_container_swap::value; }
+
+    static constexpr bool _S_always_equal()
+    { return _Base_type::is_always_equal::value; }
+
+    static constexpr bool _S_nothrow_move()
+    { return _S_propagate_on_move_assign() || _S_always_equal(); }
+
+    template<typename _Tp>
+      struct rebind
+      { typedef typename _Base_type::template rebind_alloc<_Tp> other; };
+#else // ! C++11
+
+    typedef typename _Alloc::pointer                pointer;
+    typedef typename _Alloc::const_pointer          const_pointer;
+    typedef typename _Alloc::value_type             value_type;
+    typedef typename _Alloc::reference              reference;
+    typedef typename _Alloc::const_reference        const_reference;
+    typedef typename _Alloc::size_type              size_type;
+    typedef typename _Alloc::difference_type        difference_type;
+
+    _GLIBCXX_NODISCARD static pointer
+    allocate(_Alloc& __a, size_type __n)
+    { return __a.allocate(__n); }
+
+    template<typename _Hint>
+      _GLIBCXX_NODISCARD static pointer
+      allocate(_Alloc& __a, size_type __n, _Hint __hint)
+      { return __a.allocate(__n, __hint); }
+
+    static void deallocate(_Alloc& __a, pointer __p, size_type __n)
+    { __a.deallocate(__p, __n); }
+
+    template<typename _Tp>
+      static void construct(_Alloc& __a, pointer __p, const _Tp& __arg)
+      { __a.construct(__p, __arg); }
+
+    static void destroy(_Alloc& __a, pointer __p)
+    { __a.destroy(__p); }
+
+    static size_type max_size(const _Alloc& __a)
+    { return __a.max_size(); }
+
+    static const _Alloc& _S_select_on_copy(const _Alloc& __a) { return __a; }
+
+    static void _S_on_swap(_Alloc& __a, _Alloc& __b)
+    {
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 431. Swapping containers with unequal allocators.
+      std::__alloc_swap<_Alloc>::_S_do_it(__a, __b);
+    }
+
+    template<typename _Tp>
+      struct rebind
+      { typedef typename _Alloc::template rebind<_Tp>::other other; };
+#endif // C++11
+  };
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace __gnu_cxx
+
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@ext@alloc_traits.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@ext@alloc_traits.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@ext@atomicity.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@ext@atomicity.h
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@ext@atomicity.h
@@ -0,0 +1,127 @@
+// Support for atomic operations -*- C++ -*-
+
+// Copyright (C) 2004-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file ext/atomicity.h
+ *  This file is a GNU extension to the Standard C++ Library.
+ */
+
+#ifndef _GLIBCXX_ATOMICITY_H
+#define _GLIBCXX_ATOMICITY_H	1
+
+#pragma GCC system_header
+
+#include <bits/c++config.h>
+#include <bits/gthr.h>
+#include <bits/atomic_word.h>
+#if __has_include(<sys/single_threaded.h>)
+# include <sys/single_threaded.h>
+#endif
+
+namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  __attribute__((__always_inline__))
+  inline bool
+  __is_single_threaded() _GLIBCXX_NOTHROW
+  {
+#ifndef __GTHREADS
+    return true;
+#elif __has_include(<sys/single_threaded.h>)
+    return ::__libc_single_threaded;
+#else
+    return !__gthread_active_p();
+#endif
+  }
+
+  // Functions for portable atomic access.
+  // To abstract locking primitives across all thread policies, use:
+  // __exchange_and_add_dispatch
+  // __atomic_add_dispatch
+#ifdef _GLIBCXX_ATOMIC_BUILTINS
+  inline _Atomic_word
+  __attribute__((__always_inline__))
+  __exchange_and_add(volatile _Atomic_word* __mem, int __val)
+  { return __atomic_fetch_add(__mem, __val, __ATOMIC_ACQ_REL); }
+
+  inline void
+  __attribute__((__always_inline__))
+  __atomic_add(volatile _Atomic_word* __mem, int __val)
+  { __atomic_fetch_add(__mem, __val, __ATOMIC_ACQ_REL); }
+#else
+  _Atomic_word
+  __exchange_and_add(volatile _Atomic_word*, int) _GLIBCXX_NOTHROW;
+
+  void
+  __atomic_add(volatile _Atomic_word*, int) _GLIBCXX_NOTHROW;
+#endif
+
+  inline _Atomic_word
+  __attribute__((__always_inline__))
+  __exchange_and_add_single(_Atomic_word* __mem, int __val)
+  {
+    _Atomic_word __result = *__mem;
+    *__mem += __val;
+    return __result;
+  }
+
+  inline void
+  __attribute__((__always_inline__))
+  __atomic_add_single(_Atomic_word* __mem, int __val)
+  { *__mem += __val; }
+
+  inline _Atomic_word
+  __attribute__ ((__always_inline__))
+  __exchange_and_add_dispatch(_Atomic_word* __mem, int __val)
+  {
+    if (__is_single_threaded())
+      return __exchange_and_add_single(__mem, __val);
+    else
+      return __exchange_and_add(__mem, __val);
+  }
+
+  inline void
+  __attribute__ ((__always_inline__))
+  __atomic_add_dispatch(_Atomic_word* __mem, int __val)
+  {
+    if (__is_single_threaded())
+      __atomic_add_single(__mem, __val);
+    else
+      __atomic_add(__mem, __val);
+  }
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+// Even if the CPU doesn't need a memory barrier, we need to ensure
+// that the compiler doesn't reorder memory accesses across the
+// barriers.
+#ifndef _GLIBCXX_READ_MEM_BARRIER
+#define _GLIBCXX_READ_MEM_BARRIER __atomic_thread_fence (__ATOMIC_ACQUIRE)
+#endif
+#ifndef _GLIBCXX_WRITE_MEM_BARRIER
+#define _GLIBCXX_WRITE_MEM_BARRIER __atomic_thread_fence (__ATOMIC_RELEASE)
+#endif
+
+#endif 
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@ext@atomicity.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@ext@atomicity.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@ext@concurrence.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@ext@concurrence.h
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@ext@concurrence.h
@@ -0,0 +1,315 @@
+// Support for concurrent programing -*- C++ -*-
+
+// Copyright (C) 2003-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file ext/concurrence.h
+ *  This file is a GNU extension to the Standard C++ Library.
+ */
+
+#ifndef _CONCURRENCE_H
+#define _CONCURRENCE_H 1
+
+#pragma GCC system_header
+
+#include <exception>
+#include <bits/gthr.h> 
+#include <bits/functexcept.h>
+#include <bits/cpp_type_traits.h>
+#include <ext/type_traits.h>
+
+namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  // Available locking policies:
+  // _S_single    single-threaded code that doesn't need to be locked.
+  // _S_mutex     multi-threaded code that requires additional support
+  //              from gthr.h or abstraction layers in concurrence.h.
+  // _S_atomic    multi-threaded code using atomic operations.
+  enum _Lock_policy { _S_single, _S_mutex, _S_atomic }; 
+
+  // Compile time constant that indicates prefered locking policy in
+  // the current configuration.
+  static const _Lock_policy __default_lock_policy = 
+#ifndef __GTHREADS
+  _S_single;
+#elif defined _GLIBCXX_HAVE_ATOMIC_LOCK_POLICY
+  _S_atomic;
+#else
+  _S_mutex;
+#endif
+
+  // NB: As this is used in libsupc++, need to only depend on
+  // exception. No stdexception classes, no use of std::string.
+  class __concurrence_lock_error : public std::exception
+  {
+  public:
+    virtual char const*
+    what() const throw()
+    { return "__gnu_cxx::__concurrence_lock_error"; }
+  };
+
+  class __concurrence_unlock_error : public std::exception
+  {
+  public:
+    virtual char const*
+    what() const throw()
+    { return "__gnu_cxx::__concurrence_unlock_error"; }
+  };
+
+  class __concurrence_broadcast_error : public std::exception
+  {
+  public:
+    virtual char const*
+    what() const throw()
+    { return "__gnu_cxx::__concurrence_broadcast_error"; }
+  };
+
+  class __concurrence_wait_error : public std::exception
+  {
+  public:
+    virtual char const*
+    what() const throw()
+    { return "__gnu_cxx::__concurrence_wait_error"; }
+  };
+
+  // Substitute for concurrence_error object in the case of -fno-exceptions.
+  inline void
+  __throw_concurrence_lock_error()
+  { _GLIBCXX_THROW_OR_ABORT(__concurrence_lock_error()); }
+
+  inline void
+  __throw_concurrence_unlock_error()
+  { _GLIBCXX_THROW_OR_ABORT(__concurrence_unlock_error()); }
+
+#ifdef __GTHREAD_HAS_COND
+  inline void
+  __throw_concurrence_broadcast_error()
+  { _GLIBCXX_THROW_OR_ABORT(__concurrence_broadcast_error()); }
+
+  inline void
+  __throw_concurrence_wait_error()
+  { _GLIBCXX_THROW_OR_ABORT(__concurrence_wait_error()); }
+#endif
+ 
+  class __mutex 
+  {
+  private:
+#if __GTHREADS && defined __GTHREAD_MUTEX_INIT
+    __gthread_mutex_t _M_mutex = __GTHREAD_MUTEX_INIT;
+#else
+    __gthread_mutex_t _M_mutex;
+#endif
+
+    __mutex(const __mutex&);
+    __mutex& operator=(const __mutex&);
+
+  public:
+    __mutex() 
+    { 
+#if __GTHREADS && ! defined __GTHREAD_MUTEX_INIT
+      if (__gthread_active_p())
+	__GTHREAD_MUTEX_INIT_FUNCTION(&_M_mutex);
+#endif
+    }
+
+#if __GTHREADS && ! defined __GTHREAD_MUTEX_INIT
+    ~__mutex() 
+    { 
+      if (__gthread_active_p())
+	__gthread_mutex_destroy(&_M_mutex); 
+    }
+#endif 
+
+    void lock()
+    {
+#if __GTHREADS
+      if (__gthread_active_p())
+	{
+	  if (__gthread_mutex_lock(&_M_mutex) != 0)
+	    __throw_concurrence_lock_error();
+	}
+#endif
+    }
+    
+    void unlock()
+    {
+#if __GTHREADS
+      if (__gthread_active_p())
+	{
+	  if (__gthread_mutex_unlock(&_M_mutex) != 0)
+	    __throw_concurrence_unlock_error();
+	}
+#endif
+    }
+
+    __gthread_mutex_t* gthread_mutex(void)
+      { return &_M_mutex; }
+  };
+
+  class __recursive_mutex 
+  {
+  private:
+#if __GTHREADS && defined __GTHREAD_RECURSIVE_MUTEX_INIT
+    __gthread_recursive_mutex_t _M_mutex = __GTHREAD_RECURSIVE_MUTEX_INIT;
+#else
+    __gthread_recursive_mutex_t _M_mutex;
+#endif
+
+    __recursive_mutex(const __recursive_mutex&);
+    __recursive_mutex& operator=(const __recursive_mutex&);
+
+  public:
+    __recursive_mutex() 
+    { 
+#if __GTHREADS && ! defined __GTHREAD_RECURSIVE_MUTEX_INIT
+      if (__gthread_active_p())
+	__GTHREAD_RECURSIVE_MUTEX_INIT_FUNCTION(&_M_mutex);
+#endif
+    }
+
+#if __GTHREADS && ! defined __GTHREAD_RECURSIVE_MUTEX_INIT
+    ~__recursive_mutex()
+    {
+      if (__gthread_active_p())
+	__gthread_recursive_mutex_destroy(&_M_mutex);
+    }
+#endif
+
+    void lock()
+    { 
+#if __GTHREADS
+      if (__gthread_active_p())
+	{
+	  if (__gthread_recursive_mutex_lock(&_M_mutex) != 0)
+	    __throw_concurrence_lock_error();
+	}
+#endif
+    }
+    
+    void unlock()
+    { 
+#if __GTHREADS
+      if (__gthread_active_p())
+	{
+	  if (__gthread_recursive_mutex_unlock(&_M_mutex) != 0)
+	    __throw_concurrence_unlock_error();
+	}
+#endif
+    }
+
+    __gthread_recursive_mutex_t* gthread_recursive_mutex(void)
+    { return &_M_mutex; }
+  };
+
+  /// Scoped lock idiom.
+  // Acquire the mutex here with a constructor call, then release with
+  // the destructor call in accordance with RAII style.
+  class __scoped_lock
+  {
+  public:
+    typedef __mutex __mutex_type;
+
+  private:
+    __mutex_type& _M_device;
+
+    __scoped_lock(const __scoped_lock&);
+    __scoped_lock& operator=(const __scoped_lock&);
+
+  public:
+    explicit __scoped_lock(__mutex_type& __name) : _M_device(__name)
+    { _M_device.lock(); }
+
+    ~__scoped_lock() throw()
+    { _M_device.unlock(); }
+  };
+
+#ifdef __GTHREAD_HAS_COND
+  class __cond
+  {
+  private:
+#if __GTHREADS && defined __GTHREAD_COND_INIT
+    __gthread_cond_t _M_cond = __GTHREAD_COND_INIT;
+#else
+    __gthread_cond_t _M_cond;
+#endif
+
+    __cond(const __cond&);
+    __cond& operator=(const __cond&);
+
+  public:
+    __cond() 
+    { 
+#if __GTHREADS && ! defined __GTHREAD_COND_INIT
+      if (__gthread_active_p())
+	__GTHREAD_COND_INIT_FUNCTION(&_M_cond);
+#endif
+    }
+
+#if __GTHREADS && ! defined __GTHREAD_COND_INIT
+    ~__cond() 
+    { 
+      if (__gthread_active_p())
+	__gthread_cond_destroy(&_M_cond); 
+    }
+#endif 
+
+    void broadcast()
+    {
+#if __GTHREADS
+      if (__gthread_active_p())
+	{
+	  if (__gthread_cond_broadcast(&_M_cond) != 0)
+	    __throw_concurrence_broadcast_error();
+	}
+#endif
+    }
+
+    void wait(__mutex *mutex)
+    {
+#if __GTHREADS
+      {
+	  if (__gthread_cond_wait(&_M_cond, mutex->gthread_mutex()) != 0)
+	    __throw_concurrence_wait_error();
+      }
+#endif
+    }
+
+    void wait_recursive(__recursive_mutex *mutex)
+    {
+#if __GTHREADS
+      {
+	  if (__gthread_cond_wait_recursive(&_M_cond,
+					    mutex->gthread_recursive_mutex())
+	      != 0)
+	    __throw_concurrence_wait_error();
+      }
+#endif
+    }
+  };
+#endif
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@ext@concurrence.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@ext@concurrence.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@ext@numeric_traits.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@ext@numeric_traits.h
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index 0000000000000000000000000000000000000000..87e20cc804bd59c15af48b3bb7c0d97e6a94c97e
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@ext@numeric_traits.h
@@ -0,0 +1,241 @@
+// -*- C++ -*-
+
+// Copyright (C) 2007-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the terms
+// of the GNU General Public License as published by the Free Software
+// Foundation; either version 3, or (at your option) any later
+// version.
+
+// This library is distributed in the hope that it will be useful, but
+// WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+// General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file ext/numeric_traits.h
+ *  This file is a GNU extension to the Standard C++ Library.
+ */
+
+#ifndef _EXT_NUMERIC_TRAITS
+#define _EXT_NUMERIC_TRAITS 1
+
+#pragma GCC system_header
+
+#include <bits/cpp_type_traits.h>
+#include <ext/type_traits.h>
+
+namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  // Compile time constants for builtin types.
+  // In C++98 std::numeric_limits member functions are not constant expressions
+  // (that changed in C++11 with the addition of 'constexpr').
+  // Even for C++11, this header is smaller than <limits> and can be used
+  // when only is_signed, digits, min, or max values are needed for integers,
+  // or is_signed, digits10, max_digits10, or max_exponent10 for floats.
+
+  // Unlike __is_integer (and std::is_integral) this trait is true for
+  // non-standard built-in integer types such as __int128 and __int20.
+  template<typename _Tp>
+    struct __is_integer_nonstrict
+    : public std::__is_integer<_Tp>
+    {
+      using std::__is_integer<_Tp>::__value;
+
+      // The number of bits in the value representation.
+      enum { __width = __value ? sizeof(_Tp) * __CHAR_BIT__ : 0 };
+    };
+
+  template<typename _Value>
+    struct __numeric_traits_integer
+    {
+#if __cplusplus >= 201103L
+      static_assert(__is_integer_nonstrict<_Value>::__value,
+		    "invalid specialization");
+#endif
+
+      // NB: these two are also available in std::numeric_limits as compile
+      // time constants, but <limits> is big and we can avoid including it.
+      static const bool __is_signed = (_Value)(-1) < 0;
+      static const int __digits
+	= __is_integer_nonstrict<_Value>::__width - __is_signed;
+
+      // The initializers must be constants so that __max and __min are too.
+      static const _Value __max = __is_signed
+	? (((((_Value)1 << (__digits - 1)) - 1) << 1) + 1)
+	: ~(_Value)0;
+      static const _Value __min = __is_signed ? -__max - 1 : (_Value)0;
+    };
+
+  template<typename _Value>
+    const _Value __numeric_traits_integer<_Value>::__min;
+
+  template<typename _Value>
+    const _Value __numeric_traits_integer<_Value>::__max;
+
+  template<typename _Value>
+    const bool __numeric_traits_integer<_Value>::__is_signed;
+
+  template<typename _Value>
+    const int __numeric_traits_integer<_Value>::__digits;
+
+  // Enable __numeric_traits_integer for types where the __is_integer_nonstrict
+  // primary template doesn't give the right answer.
+#define _GLIBCXX_INT_N_TRAITS(T, WIDTH)			\
+  __extension__						\
+  template<> struct __is_integer_nonstrict<T>		\
+  {							\
+    enum { __value = 1 };				\
+    typedef std::__true_type __type;			\
+    enum { __width = WIDTH };				\
+  };							\
+  __extension__						\
+  template<> struct __is_integer_nonstrict<unsigned T>	\
+  {							\
+    enum { __value = 1 };				\
+    typedef std::__true_type __type;			\
+    enum { __width = WIDTH };				\
+  };
+
+  // We need to specify the width for some __intNN types because they
+  // have padding bits, e.g. the object representation of __int20 has 32 bits,
+  // but its width (number of bits in the value representation) is only 20.
+#if defined __GLIBCXX_TYPE_INT_N_0 && __GLIBCXX_BITSIZE_INT_N_0 % __CHAR_BIT__
+  _GLIBCXX_INT_N_TRAITS(__GLIBCXX_TYPE_INT_N_0, __GLIBCXX_BITSIZE_INT_N_0)
+#endif
+#if defined __GLIBCXX_TYPE_INT_N_1 && __GLIBCXX_BITSIZE_INT_N_1 % __CHAR_BIT__
+  _GLIBCXX_INT_N_TRAITS(__GLIBCXX_TYPE_INT_N_1, __GLIBCXX_BITSIZE_INT_N_1)
+#endif
+#if defined __GLIBCXX_TYPE_INT_N_2 && __GLIBCXX_BITSIZE_INT_N_2 % __CHAR_BIT__
+  _GLIBCXX_INT_N_TRAITS(__GLIBCXX_TYPE_INT_N_2, __GLIBCXX_BITSIZE_INT_N_2)
+#endif
+#if defined __GLIBCXX_TYPE_INT_N_3 && __GLIBCXX_BITSIZE_INT_N_3 % __CHAR_BIT__
+  _GLIBCXX_INT_N_TRAITS(__GLIBCXX_TYPE_INT_N_3, __GLIBCXX_BITSIZE_INT_N_3)
+#endif
+
+#if defined __STRICT_ANSI__ && defined __SIZEOF_INT128__
+  // In strict modes __is_integer<__int128> is false,
+  // but we still want to define __numeric_traits_integer<__int128>.
+  _GLIBCXX_INT_N_TRAITS(__int128, 128)
+#endif
+
+#undef _GLIBCXX_INT_N_TRAITS
+
+#if __cplusplus >= 201103L
+  /// Convenience alias for __numeric_traits<integer-type>.
+  template<typename _Tp>
+    using __int_traits = __numeric_traits_integer<_Tp>;
+#endif
+
+#define __glibcxx_floating(_Tp, _Fval, _Dval, _LDval) \
+  (std::__are_same<_Tp, float>::__value ? _Fval \
+   : std::__are_same<_Tp, double>::__value ? _Dval : _LDval)
+
+#define __glibcxx_max_digits10(_Tp) \
+  (2 + __glibcxx_floating(_Tp, __FLT_MANT_DIG__, __DBL_MANT_DIG__, \
+			  __LDBL_MANT_DIG__) * 643L / 2136)
+
+#define __glibcxx_digits10(_Tp) \
+  __glibcxx_floating(_Tp, __FLT_DIG__, __DBL_DIG__, __LDBL_DIG__)
+
+#define __glibcxx_max_exponent10(_Tp) \
+  __glibcxx_floating(_Tp, __FLT_MAX_10_EXP__, __DBL_MAX_10_EXP__, \
+		     __LDBL_MAX_10_EXP__)
+
+  // N.B. this only supports float, double and long double (no __float128 etc.)
+  template<typename _Value>
+    struct __numeric_traits_floating
+    {
+      // Only floating point types. See N1822.
+      static const int __max_digits10 = __glibcxx_max_digits10(_Value);
+
+      // See above comment...
+      static const bool __is_signed = true;
+      static const int __digits10 = __glibcxx_digits10(_Value);
+      static const int __max_exponent10 = __glibcxx_max_exponent10(_Value);
+    };
+
+  template<typename _Value>
+    const int __numeric_traits_floating<_Value>::__max_digits10;
+
+  template<typename _Value>
+    const bool __numeric_traits_floating<_Value>::__is_signed;
+
+  template<typename _Value>
+    const int __numeric_traits_floating<_Value>::__digits10;
+
+  template<typename _Value>
+    const int __numeric_traits_floating<_Value>::__max_exponent10;
+
+#undef __glibcxx_floating
+#undef __glibcxx_max_digits10
+#undef __glibcxx_digits10
+#undef __glibcxx_max_exponent10
+
+  template<typename _Value>
+    struct __numeric_traits
+    : public __numeric_traits_integer<_Value>
+    { };
+
+  template<>
+    struct __numeric_traits<float>
+    : public __numeric_traits_floating<float>
+    { };
+
+  template<>
+    struct __numeric_traits<double>
+    : public __numeric_traits_floating<double>
+    { };
+
+  template<>
+    struct __numeric_traits<long double>
+    : public __numeric_traits_floating<long double>
+    { };
+
+#ifdef _GLIBCXX_LONG_DOUBLE_ALT128_COMPAT
+# if defined __LONG_DOUBLE_IEEE128__
+  // long double is __ieee128, define traits for __ibm128
+  template<>
+    struct __numeric_traits_floating<__ibm128>
+    {
+      static const int __max_digits10 = 33;
+      static const bool __is_signed = true;
+      static const int __digits10 = 31;
+      static const int __max_exponent10 = 308;
+    };
+  template<>
+    struct __numeric_traits<__ibm128>
+    : public __numeric_traits_floating<__ibm128>
+    { };
+# elif defined __LONG_DOUBLE_IBM128__
+  // long double is __ibm128, define traits for __ieee128
+  template<>
+    struct __numeric_traits_floating<__ieee128>
+    {
+      static const int __max_digits10 = 36;
+      static const bool __is_signed = true;
+      static const int __digits10 = 33;
+      static const int __max_exponent10 = 4932;
+    };
+  template<>
+    struct __numeric_traits<__ieee128>
+    : public __numeric_traits_floating<__ieee128>
+    { };
+# endif
+#endif
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@ext@numeric_traits.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@ext@numeric_traits.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@ext@string_conversions.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@ext@string_conversions.h
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index 0000000000000000000000000000000000000000..fc03974b5a0935f268d99e0e1355f1719e3a7291
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@ext@string_conversions.h
@@ -0,0 +1,123 @@
+// String Conversions -*- C++ -*-
+
+// Copyright (C) 2008-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file ext/string_conversions.h
+ *  This file is a GNU extension to the Standard C++ Library.
+ */
+
+#ifndef _STRING_CONVERSIONS_H
+#define _STRING_CONVERSIONS_H 1
+
+#pragma GCC system_header
+
+#if __cplusplus < 201103L
+# include <bits/c++0x_warning.h>
+#else
+
+#include <bits/c++config.h>
+#include <ext/numeric_traits.h>
+#include <bits/functexcept.h>
+#include <cstdlib>
+#include <cwchar>
+#include <cstdio>
+#include <cerrno>
+
+namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  // Helper for all the sto* functions.
+  template<typename _TRet, typename _Ret = _TRet, typename _CharT,
+	   typename... _Base>
+    _Ret
+    __stoa(_TRet (*__convf) (const _CharT*, _CharT**, _Base...),
+	   const char* __name, const _CharT* __str, std::size_t* __idx,
+	   _Base... __base)
+    {
+      _Ret __ret;
+
+      _CharT* __endptr;
+
+      struct _Save_errno {
+	_Save_errno() : _M_errno(errno) { errno = 0; }
+	~_Save_errno() { if (errno == 0) errno = _M_errno; }
+	int _M_errno;
+      } const __save_errno;
+
+      struct _Range_chk {
+	  static bool
+	  _S_chk(_TRet, std::false_type) { return false; }
+
+	  static bool
+	  _S_chk(_TRet __val, std::true_type) // only called when _Ret is int
+	  {
+	    return __val < _TRet(__numeric_traits<int>::__min)
+	      || __val > _TRet(__numeric_traits<int>::__max);
+	  }
+      };
+
+      const _TRet __tmp = __convf(__str, &__endptr, __base...);
+
+      if (__endptr == __str)
+	std::__throw_invalid_argument(__name);
+      else if (errno == ERANGE
+	  || _Range_chk::_S_chk(__tmp, std::is_same<_Ret, int>{}))
+	std::__throw_out_of_range(__name);
+      else
+	__ret = __tmp;
+
+      if (__idx)
+	*__idx = __endptr - __str;
+
+      return __ret;
+    }
+
+  // Helper for the to_string / to_wstring functions.
+  template<typename _String, typename _CharT = typename _String::value_type>
+    _String
+    __to_xstring(int (*__convf) (_CharT*, std::size_t, const _CharT*,
+				 __builtin_va_list), std::size_t __n,
+		 const _CharT* __fmt, ...)
+    {
+      // XXX Eventually the result should be constructed in-place in
+      // the __cxx11 string, likely with the help of internal hooks.
+      _CharT* __s = static_cast<_CharT*>(__builtin_alloca(sizeof(_CharT)
+							  * __n));
+
+      __builtin_va_list __args;
+      __builtin_va_start(__args, __fmt);
+
+      const int __len = __convf(__s, __n, __fmt, __args);
+
+      __builtin_va_end(__args);
+
+      return _String(__s, __s + __len);
+    }
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif // C++11
+
+#endif // _STRING_CONVERSIONS_H
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@ext@string_conversions.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@ext@string_conversions.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@ext@type_traits.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@ext@type_traits.h
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index 0000000000000000000000000000000000000000..27fae8234363ecc50f955dca4843d9e06b6379ba
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@ext@type_traits.h
@@ -0,0 +1,243 @@
+// -*- C++ -*-
+
+// Copyright (C) 2005-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the terms
+// of the GNU General Public License as published by the Free Software
+// Foundation; either version 3, or (at your option) any later
+// version.
+
+// This library is distributed in the hope that it will be useful, but
+// WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+// General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file ext/type_traits.h
+ *  This file is a GNU extension to the Standard C++ Library.
+ */
+
+#ifndef _EXT_TYPE_TRAITS
+#define _EXT_TYPE_TRAITS 1
+
+#pragma GCC system_header
+
+#include <bits/c++config.h>
+#include <bits/cpp_type_traits.h>
+
+extern "C++" {
+
+namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  // Define a nested type if some predicate holds.
+  template<bool, typename>
+    struct __enable_if 
+    { };
+
+  template<typename _Tp>
+    struct __enable_if<true, _Tp>
+    { typedef _Tp __type; };
+
+
+  // Conditional expression for types. If true, first, if false, second.
+  template<bool _Cond, typename _Iftrue, typename _Iffalse>
+    struct __conditional_type
+    { typedef _Iftrue __type; };
+
+  template<typename _Iftrue, typename _Iffalse>
+    struct __conditional_type<false, _Iftrue, _Iffalse>
+    { typedef _Iffalse __type; };
+
+
+  // Given an integral builtin type, return the corresponding unsigned type.
+  template<typename _Tp>
+    struct __add_unsigned
+    { 
+    private:
+      typedef __enable_if<std::__is_integer<_Tp>::__value, _Tp> __if_type;
+      
+    public:
+      typedef typename __if_type::__type __type; 
+    };
+
+  template<>
+    struct __add_unsigned<char>
+    { typedef unsigned char __type; };
+
+  template<>
+    struct __add_unsigned<signed char>
+    { typedef unsigned char __type; };
+
+  template<>
+    struct __add_unsigned<short>
+    { typedef unsigned short __type; };
+
+  template<>
+    struct __add_unsigned<int>
+    { typedef unsigned int __type; };
+
+  template<>
+    struct __add_unsigned<long>
+    { typedef unsigned long __type; };
+
+  template<>
+    struct __add_unsigned<long long>
+    { typedef unsigned long long __type; };
+
+  // Declare but don't define.
+  template<>
+    struct __add_unsigned<bool>;
+
+  template<>
+    struct __add_unsigned<wchar_t>;
+
+
+  // Given an integral builtin type, return the corresponding signed type.
+  template<typename _Tp>
+    struct __remove_unsigned
+    { 
+    private:
+      typedef __enable_if<std::__is_integer<_Tp>::__value, _Tp> __if_type;
+      
+    public:
+      typedef typename __if_type::__type __type; 
+    };
+
+  template<>
+    struct __remove_unsigned<char>
+    { typedef signed char __type; };
+
+  template<>
+    struct __remove_unsigned<unsigned char>
+    { typedef signed char __type; };
+
+  template<>
+    struct __remove_unsigned<unsigned short>
+    { typedef short __type; };
+
+  template<>
+    struct __remove_unsigned<unsigned int>
+    { typedef int __type; };
+
+  template<>
+    struct __remove_unsigned<unsigned long>
+    { typedef long __type; };
+
+  template<>
+    struct __remove_unsigned<unsigned long long>
+    { typedef long long __type; };
+
+  // Declare but don't define.
+  template<>
+    struct __remove_unsigned<bool>;
+
+  template<>
+    struct __remove_unsigned<wchar_t>;
+
+
+  // For use in string and vstring.
+  template<typename _Type>
+    _GLIBCXX_CONSTEXPR
+    inline bool
+    __is_null_pointer(_Type* __ptr)
+    { return __ptr == 0; }
+
+  template<typename _Type>
+    _GLIBCXX_CONSTEXPR
+    inline bool
+    __is_null_pointer(_Type)
+    { return false; }
+
+#if __cplusplus >= 201103L
+  constexpr bool
+  __is_null_pointer(std::nullptr_t)
+  { return true; }
+#endif
+
+  // For arithmetic promotions in <complex> and <cmath>
+
+  template<typename _Tp, bool = std::__is_integer<_Tp>::__value>
+    struct __promote
+    { typedef double __type; };
+
+  // No nested __type member for non-integer non-floating point types,
+  // allows this type to be used for SFINAE to constrain overloads in
+  // <cmath> and <complex> to only the intended types.
+  template<typename _Tp>
+    struct __promote<_Tp, false>
+    { };
+
+  template<>
+    struct __promote<long double>
+    { typedef long double __type; };
+
+  template<>
+    struct __promote<double>
+    { typedef double __type; };
+
+  template<>
+    struct __promote<float>
+    { typedef float __type; };
+
+#if __cpp_fold_expressions
+
+  template<typename... _Tp>
+    using __promoted_t = decltype((typename __promote<_Tp>::__type(0) + ...));
+
+  // Deducing the promoted type is done by __promoted_t<_Tp...>,
+  // then __promote is used to provide the nested __type member.
+  template<typename _Tp, typename _Up>
+    using __promote_2 = __promote<__promoted_t<_Tp, _Up>>;
+
+  template<typename _Tp, typename _Up, typename _Vp>
+    using __promote_3 = __promote<__promoted_t<_Tp, _Up, _Vp>>;
+
+  template<typename _Tp, typename _Up, typename _Vp, typename _Wp>
+    using __promote_4 = __promote<__promoted_t<_Tp, _Up, _Vp, _Wp>>;
+
+#else
+
+  template<typename _Tp, typename _Up,
+           typename _Tp2 = typename __promote<_Tp>::__type,
+           typename _Up2 = typename __promote<_Up>::__type>
+    struct __promote_2
+    {
+      typedef __typeof__(_Tp2() + _Up2()) __type;
+    };
+
+  template<typename _Tp, typename _Up, typename _Vp,
+           typename _Tp2 = typename __promote<_Tp>::__type,
+           typename _Up2 = typename __promote<_Up>::__type,
+           typename _Vp2 = typename __promote<_Vp>::__type>
+    struct __promote_3
+    {
+      typedef __typeof__(_Tp2() + _Up2() + _Vp2()) __type;
+    };
+
+  template<typename _Tp, typename _Up, typename _Vp, typename _Wp,
+           typename _Tp2 = typename __promote<_Tp>::__type,
+           typename _Up2 = typename __promote<_Up>::__type,
+           typename _Vp2 = typename __promote<_Vp>::__type,
+           typename _Wp2 = typename __promote<_Wp>::__type>
+    struct __promote_4
+    {
+      typedef __typeof__(_Tp2() + _Up2() + _Vp2() + _Wp2()) __type;
+    };
+#endif
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+} // extern "C++"
+
+#endif 
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@fenv.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@fenv.h
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@@ -0,0 +1,81 @@
+// -*- C++ -*- compatibility header.
+
+// Copyright (C) 2007-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file fenv.h
+ *  This is a Standard C++ Library header.
+ */
+
+#ifndef _GLIBCXX_FENV_H
+#define _GLIBCXX_FENV_H 1
+
+#pragma GCC system_header
+
+#include <bits/c++config.h>
+#if _GLIBCXX_HAVE_FENV_H
+# include_next <fenv.h>
+#endif
+
+#if __cplusplus >= 201103L
+
+#if _GLIBCXX_USE_C99_FENV_TR1
+
+#undef feclearexcept
+#undef fegetexceptflag
+#undef feraiseexcept
+#undef fesetexceptflag
+#undef fetestexcept
+#undef fegetround
+#undef fesetround
+#undef fegetenv
+#undef feholdexcept
+#undef fesetenv
+#undef feupdateenv
+
+namespace std
+{
+  // types
+  using ::fenv_t;
+  using ::fexcept_t;
+
+  // functions
+  using ::feclearexcept;
+  using ::fegetexceptflag;
+  using ::feraiseexcept;
+  using ::fesetexceptflag;
+  using ::fetestexcept;
+
+  using ::fegetround;
+  using ::fesetround;
+
+  using ::fegetenv;
+  using ::feholdexcept;
+  using ::fesetenv;
+  using ::feupdateenv;
+} // namespace
+
+#endif // _GLIBCXX_USE_C99_FENV_TR1
+
+#endif // C++11
+
+#endif // _GLIBCXX_FENV_H
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@forward_list b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@forward_list
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@@ -0,0 +1,87 @@
+// <forward_list> -*- C++ -*-
+
+// Copyright (C) 2008-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file include/forward_list
+ *  This is a Standard C++ Library header.
+ */
+
+#ifndef _GLIBCXX_FORWARD_LIST
+#define _GLIBCXX_FORWARD_LIST 1
+
+#pragma GCC system_header
+
+#if __cplusplus < 201103L
+# include <bits/c++0x_warning.h>
+#else
+
+#include <bits/forward_list.h>
+#include <bits/range_access.h>
+#include <bits/forward_list.tcc>
+
+#ifdef _GLIBCXX_DEBUG
+# include <debug/forward_list>
+#endif
+
+#if __cplusplus >= 201703L
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+  namespace pmr
+  {
+    template<typename _Tp> class polymorphic_allocator;
+    template<typename _Tp>
+      using forward_list = std::forward_list<_Tp, polymorphic_allocator<_Tp>>;
+  } // namespace pmr
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+#endif // C++17
+
+#if __cplusplus > 201703L
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+#define __cpp_lib_erase_if 202002L
+
+  template<typename _Tp, typename _Alloc, typename _Predicate>
+    inline typename forward_list<_Tp, _Alloc>::size_type 
+    erase_if(forward_list<_Tp, _Alloc>& __cont, _Predicate __pred)
+    { return __cont.remove_if(__pred); }
+
+  template<typename _Tp, typename _Alloc, typename _Up>
+    inline typename forward_list<_Tp, _Alloc>::size_type
+    erase(forward_list<_Tp, _Alloc>& __cont, const _Up& __value)
+    {
+      using __elem_type = typename forward_list<_Tp, _Alloc>::value_type;
+      return std::erase_if(__cont, [&](__elem_type& __elem) {
+	  return __elem == __value;
+      });
+    }
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+#endif // C++20
+
+#endif // C++11
+
+#endif // _GLIBCXX_FORWARD_LIST
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@fstream b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@fstream
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@@ -0,0 +1,1300 @@
+// File based streams -*- C++ -*-
+
+// Copyright (C) 1997-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file include/fstream
+ *  This is a Standard C++ Library header.
+ */
+
+//
+// ISO C++ 14882: 27.8  File-based streams
+//
+
+#ifndef _GLIBCXX_FSTREAM
+#define _GLIBCXX_FSTREAM 1
+
+#pragma GCC system_header
+
+#include <istream>
+#include <ostream>
+#include <bits/codecvt.h>
+#include <cstdio>             // For BUFSIZ
+#include <bits/basic_file.h>  // For __basic_file, __c_lock
+#if __cplusplus >= 201103L
+#include <string>             // For std::string overloads.
+#endif
+
+// This can be overridden by the target's os_defines.h
+#ifndef _GLIBCXX_BUFSIZ
+# define _GLIBCXX_BUFSIZ BUFSIZ
+#endif
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+#if __cplusplus >= 201703L
+  // Enable if _Path is a filesystem::path or experimental::filesystem::path
+  template<typename _Path, typename _Result = _Path, typename _Path2
+	   = decltype(std::declval<_Path&>().make_preferred().filename())>
+    using _If_fs_path = enable_if_t<is_same_v<_Path, _Path2>, _Result>;
+#endif // C++17
+
+
+  // [27.8.1.1] template class basic_filebuf
+  /**
+   *  @brief  The actual work of input and output (for files).
+   *  @ingroup io
+   *
+   *  @tparam _CharT  Type of character stream.
+   *  @tparam _Traits  Traits for character type, defaults to
+   *                   char_traits<_CharT>.
+   *
+   *  This class associates both its input and output sequence with an
+   *  external disk file, and maintains a joint file position for both
+   *  sequences.  Many of its semantics are described in terms of similar
+   *  behavior in the Standard C Library's @c FILE streams.
+   *
+   *  Requirements on traits_type, specific to this class:
+   *  - traits_type::pos_type must be fpos<traits_type::state_type>
+   *  - traits_type::off_type must be streamoff
+   *  - traits_type::state_type must be Assignable and DefaultConstructible,
+   *  - traits_type::state_type() must be the initial state for codecvt.
+   */
+  template<typename _CharT, typename _Traits>
+    class basic_filebuf : public basic_streambuf<_CharT, _Traits>
+    {
+#if __cplusplus >= 201103L
+      template<typename _Tp>
+	using __chk_state = __and_<is_copy_assignable<_Tp>,
+				   is_copy_constructible<_Tp>,
+				   is_default_constructible<_Tp>>;
+
+      static_assert(__chk_state<typename _Traits::state_type>::value,
+		    "state_type must be CopyAssignable, CopyConstructible"
+		    " and DefaultConstructible");
+
+      static_assert(is_same<typename _Traits::pos_type,
+			    fpos<typename _Traits::state_type>>::value,
+		    "pos_type must be fpos<state_type>");
+#endif
+    public:
+      // Types:
+      typedef _CharT                     	        char_type;
+      typedef _Traits                    	        traits_type;
+      typedef typename traits_type::int_type 		int_type;
+      typedef typename traits_type::pos_type 		pos_type;
+      typedef typename traits_type::off_type 		off_type;
+
+      typedef basic_streambuf<char_type, traits_type>  	__streambuf_type;
+      typedef basic_filebuf<char_type, traits_type>     __filebuf_type;
+      typedef __basic_file<char>		        __file_type;
+      typedef typename traits_type::state_type          __state_type;
+      typedef codecvt<char_type, char, __state_type>    __codecvt_type;
+
+      friend class ios_base; // For sync_with_stdio.
+
+    protected:
+      // Data Members:
+      // MT lock inherited from libio or other low-level io library.
+      __c_lock          	_M_lock;
+
+      // External buffer.
+      __file_type 		_M_file;
+
+      /// Place to stash in || out || in | out settings for current filebuf.
+      ios_base::openmode 	_M_mode;
+
+      // Beginning state type for codecvt.
+      __state_type 		_M_state_beg;
+
+      // During output, the state that corresponds to pptr(),
+      // during input, the state that corresponds to egptr() and
+      // _M_ext_next.
+      __state_type		_M_state_cur;
+
+      // Not used for output. During input, the state that corresponds
+      // to eback() and _M_ext_buf.
+      __state_type		_M_state_last;
+
+      /// Pointer to the beginning of internal buffer.
+      char_type*		_M_buf;
+
+      /**
+       *  Actual size of internal buffer. This number is equal to the size
+       *  of the put area + 1 position, reserved for the overflow char of
+       *  a full area.
+       */
+      size_t			_M_buf_size;
+
+      // Set iff _M_buf is allocated memory from _M_allocate_internal_buffer.
+      bool			_M_buf_allocated;
+
+      /**
+       *  _M_reading == false && _M_writing == false for @b uncommitted mode;
+       *  _M_reading == true for @b read mode;
+       *  _M_writing == true for @b write mode;
+       *
+       *  NB: _M_reading == true && _M_writing == true is unused.
+       */
+      bool                      _M_reading;
+      bool                      _M_writing;
+
+      ///@{
+      /**
+       *  Necessary bits for putback buffer management.
+       *
+       *  @note pbacks of over one character are not currently supported.
+       */
+      char_type			_M_pback;
+      char_type*		_M_pback_cur_save;
+      char_type*		_M_pback_end_save;
+      bool			_M_pback_init;
+      ///@}
+
+      // Cached codecvt facet.
+      const __codecvt_type* 	_M_codecvt;
+
+      /**
+       *  Buffer for external characters. Used for input when
+       *  codecvt::always_noconv() == false. When valid, this corresponds
+       *  to eback().
+       */
+      char*			_M_ext_buf;
+
+      /**
+       *  Size of buffer held by _M_ext_buf.
+       */
+      streamsize		_M_ext_buf_size;
+
+      /**
+       *  Pointers into the buffer held by _M_ext_buf that delimit a
+       *  subsequence of bytes that have been read but not yet converted.
+       *  When valid, _M_ext_next corresponds to egptr().
+       */
+      const char*		_M_ext_next;
+      char*			_M_ext_end;
+
+      /**
+       *  Initializes pback buffers, and moves normal buffers to safety.
+       *  Assumptions:
+       *  _M_in_cur has already been moved back
+       */
+      void
+      _M_create_pback()
+      {
+	if (!_M_pback_init)
+	  {
+	    _M_pback_cur_save = this->gptr();
+	    _M_pback_end_save = this->egptr();
+	    this->setg(&_M_pback, &_M_pback, &_M_pback + 1);
+	    _M_pback_init = true;
+	  }
+      }
+
+      /**
+       *  Deactivates pback buffer contents, and restores normal buffer.
+       *  Assumptions:
+       *  The pback buffer has only moved forward.
+       */
+      void
+      _M_destroy_pback() throw()
+      {
+	if (_M_pback_init)
+	  {
+	    // Length _M_in_cur moved in the pback buffer.
+	    _M_pback_cur_save += this->gptr() != this->eback();
+	    this->setg(_M_buf, _M_pback_cur_save, _M_pback_end_save);
+	    _M_pback_init = false;
+	  }
+      }
+
+    public:
+      // Constructors/destructor:
+      /**
+       *  @brief  Does not open any files.
+       *
+       *  The default constructor initializes the parent class using its
+       *  own default ctor.
+       */
+      basic_filebuf();
+
+#if __cplusplus >= 201103L
+      basic_filebuf(const basic_filebuf&) = delete;
+      basic_filebuf(basic_filebuf&&);
+#endif
+
+      /**
+       *  @brief  The destructor closes the file first.
+       */
+      virtual
+      ~basic_filebuf()
+      {
+	__try
+	  { this->close(); }
+	__catch(...)
+	  { }
+      }
+
+#if __cplusplus >= 201103L
+      basic_filebuf& operator=(const basic_filebuf&) = delete;
+      basic_filebuf& operator=(basic_filebuf&&);
+      void swap(basic_filebuf&);
+#endif
+
+      // Members:
+      /**
+       *  @brief  Returns true if the external file is open.
+       */
+      bool
+      is_open() const throw()
+      { return _M_file.is_open(); }
+
+      /**
+       *  @brief  Opens an external file.
+       *  @param  __s  The name of the file.
+       *  @param  __mode  The open mode flags.
+       *  @return  @c this on success, NULL on failure
+       *
+       *  If a file is already open, this function immediately fails.
+       *  Otherwise it tries to open the file named @a __s using the flags
+       *  given in @a __mode.
+       *
+       *  Table 92, adapted here, gives the relation between openmode
+       *  combinations and the equivalent @c fopen() flags.
+       *  (NB: lines app, in|out|app, in|app, binary|app, binary|in|out|app,
+       *  and binary|in|app per DR 596)
+       *  <pre>
+       *  +---------------------------------------------------------+
+       *  | ios_base Flag combination            stdio equivalent   |
+       *  |binary  in  out  trunc  app                              |
+       *  +---------------------------------------------------------+
+       *  |             +                        w                  |
+       *  |             +           +            a                  |
+       *  |                         +            a                  |
+       *  |             +     +                  w                  |
+       *  |         +                            r                  |
+       *  |         +   +                        r+                 |
+       *  |         +   +     +                  w+                 |
+       *  |         +   +           +            a+                 |
+       *  |         +               +            a+                 |
+       *  +---------------------------------------------------------+
+       *  |   +         +                        wb                 |
+       *  |   +         +           +            ab                 |
+       *  |   +                     +            ab                 |
+       *  |   +         +     +                  wb                 |
+       *  |   +     +                            rb                 |
+       *  |   +     +   +                        r+b                |
+       *  |   +     +   +     +                  w+b                |
+       *  |   +     +   +           +            a+b                |
+       *  |   +     +               +            a+b                |
+       *  +---------------------------------------------------------+
+       *  </pre>
+       */
+      __filebuf_type*
+      open(const char* __s, ios_base::openmode __mode);
+
+#if _GLIBCXX_HAVE__WFOPEN && _GLIBCXX_USE_WCHAR_T
+      /**
+       *  @brief  Opens an external file.
+       *  @param  __s  The name of the file, as a wide character string.
+       *  @param  __mode  The open mode flags.
+       *  @return  @c this on success, NULL on failure
+       */
+      __filebuf_type*
+      open(const wchar_t* __s, ios_base::openmode __mode);
+#endif
+
+#if __cplusplus >= 201103L
+      /**
+       *  @brief  Opens an external file.
+       *  @param  __s  The name of the file.
+       *  @param  __mode  The open mode flags.
+       *  @return  @c this on success, NULL on failure
+       */
+      __filebuf_type*
+      open(const std::string& __s, ios_base::openmode __mode)
+      { return open(__s.c_str(), __mode); }
+
+#if __cplusplus >= 201703L
+      /**
+       *  @brief  Opens an external file.
+       *  @param  __s  The name of the file, as a filesystem::path.
+       *  @param  __mode  The open mode flags.
+       *  @return  @c this on success, NULL on failure
+       */
+      template<typename _Path>
+	_If_fs_path<_Path, __filebuf_type*>
+	open(const _Path& __s, ios_base::openmode __mode)
+	{ return open(__s.c_str(), __mode); }
+#endif // C++17
+#endif // C++11
+
+      /**
+       *  @brief  Closes the currently associated file.
+       *  @return  @c this on success, NULL on failure
+       *
+       *  If no file is currently open, this function immediately fails.
+       *
+       *  If a <em>put buffer area</em> exists, @c overflow(eof) is
+       *  called to flush all the characters.  The file is then
+       *  closed.
+       *
+       *  If any operations fail, this function also fails.
+       */
+      __filebuf_type*
+      close();
+
+    protected:
+      void
+      _M_allocate_internal_buffer();
+
+      void
+      _M_destroy_internal_buffer() throw();
+
+      // [27.8.1.4] overridden virtual functions
+      virtual streamsize
+      showmanyc();
+
+      // Stroustrup, 1998, p. 628
+      // underflow() and uflow() functions are called to get the next
+      // character from the real input source when the buffer is empty.
+      // Buffered input uses underflow()
+
+      virtual int_type
+      underflow();
+
+      virtual int_type
+      pbackfail(int_type __c = _Traits::eof());
+
+      // Stroustrup, 1998, p 648
+      // The overflow() function is called to transfer characters to the
+      // real output destination when the buffer is full. A call to
+      // overflow(c) outputs the contents of the buffer plus the
+      // character c.
+      // 27.5.2.4.5
+      // Consume some sequence of the characters in the pending sequence.
+      virtual int_type
+      overflow(int_type __c = _Traits::eof());
+
+      // Convert internal byte sequence to external, char-based
+      // sequence via codecvt.
+      bool
+      _M_convert_to_external(char_type*, streamsize);
+
+      /**
+       *  @brief  Manipulates the buffer.
+       *  @param  __s  Pointer to a buffer area.
+       *  @param  __n  Size of @a __s.
+       *  @return  @c this
+       *
+       *  If no file has been opened, and both @a __s and @a __n are zero, then
+       *  the stream becomes unbuffered.  Otherwise, @c __s is used as a
+       *  buffer; see
+       *  https://gcc.gnu.org/onlinedocs/libstdc++/manual/streambufs.html#io.streambuf.buffering
+       *  for more.
+       */
+      virtual __streambuf_type*
+      setbuf(char_type* __s, streamsize __n);
+
+      virtual pos_type
+      seekoff(off_type __off, ios_base::seekdir __way,
+	      ios_base::openmode __mode = ios_base::in | ios_base::out);
+
+      virtual pos_type
+      seekpos(pos_type __pos,
+	      ios_base::openmode __mode = ios_base::in | ios_base::out);
+
+      // Common code for seekoff, seekpos, and overflow
+      pos_type
+      _M_seek(off_type __off, ios_base::seekdir __way, __state_type __state);
+
+      int
+      _M_get_ext_pos(__state_type &__state);
+
+      virtual int
+      sync();
+
+      virtual void
+      imbue(const locale& __loc);
+
+      virtual streamsize
+      xsgetn(char_type* __s, streamsize __n);
+
+      virtual streamsize
+      xsputn(const char_type* __s, streamsize __n);
+
+      // Flushes output buffer, then writes unshift sequence.
+      bool
+      _M_terminate_output();
+
+      /**
+       *  This function sets the pointers of the internal buffer, both get
+       *  and put areas. Typically:
+       *
+       *   __off == egptr() - eback() upon underflow/uflow (@b read mode);
+       *   __off == 0 upon overflow (@b write mode);
+       *   __off == -1 upon open, setbuf, seekoff/pos (@b uncommitted mode).
+       *
+       *  NB: epptr() - pbase() == _M_buf_size - 1, since _M_buf_size
+       *  reflects the actual allocated memory and the last cell is reserved
+       *  for the overflow char of a full put area.
+       */
+      void
+      _M_set_buffer(streamsize __off)
+      {
+	const bool __testin = _M_mode & ios_base::in;
+	const bool __testout = (_M_mode & ios_base::out
+				|| _M_mode & ios_base::app);
+
+	if (__testin && __off > 0)
+	  this->setg(_M_buf, _M_buf, _M_buf + __off);
+	else
+	  this->setg(_M_buf, _M_buf, _M_buf);
+
+	if (__testout && __off == 0 && _M_buf_size > 1 )
+	  this->setp(_M_buf, _M_buf + _M_buf_size - 1);
+	else
+	  this->setp(0, 0);
+      }
+    };
+
+  // [27.8.1.5] Template class basic_ifstream
+  /**
+   *  @brief  Controlling input for files.
+   *  @ingroup io
+   *
+   *  @tparam _CharT  Type of character stream.
+   *  @tparam _Traits  Traits for character type, defaults to
+   *                   char_traits<_CharT>.
+   *
+   *  This class supports reading from named files, using the inherited
+   *  functions from std::basic_istream.  To control the associated
+   *  sequence, an instance of std::basic_filebuf is used, which this page
+   *  refers to as @c sb.
+   */
+  template<typename _CharT, typename _Traits>
+    class basic_ifstream : public basic_istream<_CharT, _Traits>
+    {
+    public:
+      // Types:
+      typedef _CharT 					char_type;
+      typedef _Traits 					traits_type;
+      typedef typename traits_type::int_type 		int_type;
+      typedef typename traits_type::pos_type 		pos_type;
+      typedef typename traits_type::off_type 		off_type;
+
+      // Non-standard types:
+      typedef basic_filebuf<char_type, traits_type> 	__filebuf_type;
+      typedef basic_istream<char_type, traits_type>	__istream_type;
+
+    private:
+      __filebuf_type	_M_filebuf;
+
+    public:
+      // Constructors/Destructors:
+      /**
+       *  @brief  Default constructor.
+       *
+       *  Initializes @c sb using its default constructor, and passes
+       *  @c &sb to the base class initializer.  Does not open any files
+       *  (you haven't given it a filename to open).
+       */
+      basic_ifstream() : __istream_type(), _M_filebuf()
+      { this->init(&_M_filebuf); }
+
+      /**
+       *  @brief  Create an input file stream.
+       *  @param  __s  Null terminated string specifying the filename.
+       *  @param  __mode  Open file in specified mode (see std::ios_base).
+       *
+       *  @c ios_base::in is automatically included in @a __mode.
+       */
+      explicit
+      basic_ifstream(const char* __s, ios_base::openmode __mode = ios_base::in)
+      : __istream_type(), _M_filebuf()
+      {
+	this->init(&_M_filebuf);
+	this->open(__s, __mode);
+      }
+
+#if _GLIBCXX_HAVE__WFOPEN && _GLIBCXX_USE_WCHAR_T
+      /**
+       *  @param  Create an input file stream.
+       *  @param  __s  Wide string specifying the filename.
+       *  @param  __mode  Open file in specified mode (see std::ios_base).
+       *
+       *  @c ios_base::in is automatically included in @a __mode.
+       */
+      basic_ifstream(const wchar_t* __s,
+		     ios_base::openmode __mode = ios_base::in)
+      : __istream_type(), _M_filebuf()
+      {
+	this->init(&_M_filebuf);
+	this->open(__s, __mode);
+      }
+#endif
+
+#if __cplusplus >= 201103L
+      /**
+       *  @brief  Create an input file stream.
+       *  @param  __s  std::string specifying the filename.
+       *  @param  __mode  Open file in specified mode (see std::ios_base).
+       *
+       *  @c ios_base::in is automatically included in @a __mode.
+       */
+      explicit
+      basic_ifstream(const std::string& __s,
+		     ios_base::openmode __mode = ios_base::in)
+      : __istream_type(), _M_filebuf()
+      {
+	this->init(&_M_filebuf);
+	this->open(__s, __mode);
+      }
+
+#if __cplusplus >= 201703L
+      /**
+       *  @brief  Create an input file stream.
+       *  @param  __s  filesystem::path specifying the filename.
+       *  @param  __mode  Open file in specified mode (see std::ios_base).
+       *
+       *  @c ios_base::in is automatically included in @a __mode.
+       */
+      template<typename _Path, typename _Require = _If_fs_path<_Path>>
+	basic_ifstream(const _Path& __s,
+		       ios_base::openmode __mode = ios_base::in)
+	: basic_ifstream(__s.c_str(), __mode)
+	{ }
+#endif // C++17
+
+      basic_ifstream(const basic_ifstream&) = delete;
+
+      basic_ifstream(basic_ifstream&& __rhs)
+      : __istream_type(std::move(__rhs)),
+      _M_filebuf(std::move(__rhs._M_filebuf))
+      { __istream_type::set_rdbuf(&_M_filebuf); }
+#endif // C++11
+
+      /**
+       *  @brief  The destructor does nothing.
+       *
+       *  The file is closed by the filebuf object, not the formatting
+       *  stream.
+       */
+      ~basic_ifstream()
+      { }
+
+#if __cplusplus >= 201103L
+      // 27.8.3.2 Assign and swap:
+
+      basic_ifstream&
+      operator=(const basic_ifstream&) = delete;
+
+      basic_ifstream&
+      operator=(basic_ifstream&& __rhs)
+      {
+	__istream_type::operator=(std::move(__rhs));
+	_M_filebuf = std::move(__rhs._M_filebuf);
+	return *this;
+      }
+
+      void
+      swap(basic_ifstream& __rhs)
+      {
+	__istream_type::swap(__rhs);
+	_M_filebuf.swap(__rhs._M_filebuf);
+      }
+#endif
+
+      // Members:
+      /**
+       *  @brief  Accessing the underlying buffer.
+       *  @return  The current basic_filebuf buffer.
+       *
+       *  This hides both signatures of std::basic_ios::rdbuf().
+       */
+      __filebuf_type*
+      rdbuf() const
+      { return const_cast<__filebuf_type*>(&_M_filebuf); }
+
+      /**
+       *  @brief  Wrapper to test for an open file.
+       *  @return  @c rdbuf()->is_open()
+       */
+      bool
+      is_open()
+      { return _M_filebuf.is_open(); }
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 365. Lack of const-qualification in clause 27
+      bool
+      is_open() const
+      { return _M_filebuf.is_open(); }
+
+      /**
+       *  @brief  Opens an external file.
+       *  @param  __s  The name of the file.
+       *  @param  __mode  The open mode flags.
+       *
+       *  Calls @c std::basic_filebuf::open(s,__mode|in).  If that function
+       *  fails, @c failbit is set in the stream's error state.
+       */
+      void
+      open(const char* __s, ios_base::openmode __mode = ios_base::in)
+      {
+	if (!_M_filebuf.open(__s, __mode | ios_base::in))
+	  this->setstate(ios_base::failbit);
+	else
+	  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+	  // 409. Closing an fstream should clear error state
+	  this->clear();
+      }
+
+#if _GLIBCXX_HAVE__WFOPEN && _GLIBCXX_USE_WCHAR_T
+      /**
+       *  @brief  Opens an external file.
+       *  @param  __s  The name of the file, as a wide character string.
+       *  @param  __mode  The open mode flags.
+       *
+       *  Calls @c std::basic_filebuf::open(__s,__mode|in).  If that function
+       *  fails, @c failbit is set in the stream's error state.
+       */
+      void
+      open(const wchar_t* __s, ios_base::openmode __mode = ios_base::in)
+      {
+	if (!_M_filebuf.open(__s, __mode | ios_base::in))
+	  this->setstate(ios_base::failbit);
+	else
+	  this->clear();
+      }
+#endif
+
+#if __cplusplus >= 201103L
+      /**
+       *  @brief  Opens an external file.
+       *  @param  __s  The name of the file.
+       *  @param  __mode  The open mode flags.
+       *
+       *  Calls @c std::basic_filebuf::open(__s,__mode|in).  If that function
+       *  fails, @c failbit is set in the stream's error state.
+       */
+      void
+      open(const std::string& __s, ios_base::openmode __mode = ios_base::in)
+      {
+	if (!_M_filebuf.open(__s, __mode | ios_base::in))
+	  this->setstate(ios_base::failbit);
+	else
+	  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+	  // 409. Closing an fstream should clear error state
+	  this->clear();
+      }
+
+#if __cplusplus >= 201703L
+      /**
+       *  @brief  Opens an external file.
+       *  @param  __s  The name of the file, as a filesystem::path.
+       *  @param  __mode  The open mode flags.
+       *
+       *  Calls @c std::basic_filebuf::open(__s,__mode|in).  If that function
+       *  fails, @c failbit is set in the stream's error state.
+       */
+      template<typename _Path>
+	_If_fs_path<_Path, void>
+	open(const _Path& __s, ios_base::openmode __mode = ios_base::in)
+	{ open(__s.c_str(), __mode); }
+#endif // C++17
+#endif // C++11
+
+      /**
+       *  @brief  Close the file.
+       *
+       *  Calls @c std::basic_filebuf::close().  If that function
+       *  fails, @c failbit is set in the stream's error state.
+       */
+      void
+      close()
+      {
+	if (!_M_filebuf.close())
+	  this->setstate(ios_base::failbit);
+      }
+    };
+
+
+  // [27.8.1.8] Template class basic_ofstream
+  /**
+   *  @brief  Controlling output for files.
+   *  @ingroup io
+   *
+   *  @tparam _CharT  Type of character stream.
+   *  @tparam _Traits  Traits for character type, defaults to
+   *                   char_traits<_CharT>.
+   *
+   *  This class supports reading from named files, using the inherited
+   *  functions from std::basic_ostream.  To control the associated
+   *  sequence, an instance of std::basic_filebuf is used, which this page
+   *  refers to as @c sb.
+   */
+  template<typename _CharT, typename _Traits>
+    class basic_ofstream : public basic_ostream<_CharT,_Traits>
+    {
+    public:
+      // Types:
+      typedef _CharT 					char_type;
+      typedef _Traits 					traits_type;
+      typedef typename traits_type::int_type 		int_type;
+      typedef typename traits_type::pos_type 		pos_type;
+      typedef typename traits_type::off_type 		off_type;
+
+      // Non-standard types:
+      typedef basic_filebuf<char_type, traits_type> 	__filebuf_type;
+      typedef basic_ostream<char_type, traits_type>	__ostream_type;
+
+    private:
+      __filebuf_type	_M_filebuf;
+
+    public:
+      // Constructors:
+      /**
+       *  @brief  Default constructor.
+       *
+       *  Initializes @c sb using its default constructor, and passes
+       *  @c &sb to the base class initializer.  Does not open any files
+       *  (you haven't given it a filename to open).
+       */
+      basic_ofstream(): __ostream_type(), _M_filebuf()
+      { this->init(&_M_filebuf); }
+
+      /**
+       *  @brief  Create an output file stream.
+       *  @param  __s  Null terminated string specifying the filename.
+       *  @param  __mode  Open file in specified mode (see std::ios_base).
+       *
+       *  @c ios_base::out is automatically included in @a __mode.
+       */
+      explicit
+      basic_ofstream(const char* __s,
+		     ios_base::openmode __mode = ios_base::out)
+      : __ostream_type(), _M_filebuf()
+      {
+	this->init(&_M_filebuf);
+	this->open(__s, __mode);
+      }
+
+#if _GLIBCXX_HAVE__WFOPEN && _GLIBCXX_USE_WCHAR_T
+      /**
+       *  @param  Create an output file stream.
+       *  @param  __s  Wide string specifying the filename.
+       *  @param  __mode  Open file in specified mode (see std::ios_base).
+       *
+       *  @c ios_base::out | @c ios_base::trunc is automatically included in
+       *  @a __mode.
+       */
+      basic_ofstream(const wchar_t* __s,
+		     ios_base::openmode __mode = ios_base::out|ios_base::trunc)
+      : __ostream_type(), _M_filebuf()
+      {
+	this->init(&_M_filebuf);
+	this->open(__s, __mode);
+      }
+#endif
+
+#if __cplusplus >= 201103L
+      /**
+       *  @brief  Create an output file stream.
+       *  @param  __s  std::string specifying the filename.
+       *  @param  __mode  Open file in specified mode (see std::ios_base).
+       *
+       *  @c ios_base::out is automatically included in @a __mode.
+       */
+      explicit
+      basic_ofstream(const std::string& __s,
+		     ios_base::openmode __mode = ios_base::out)
+      : __ostream_type(), _M_filebuf()
+      {
+	this->init(&_M_filebuf);
+	this->open(__s, __mode);
+      }
+
+#if __cplusplus >= 201703L
+      /**
+       *  @brief  Create an output file stream.
+       *  @param  __s  filesystem::path specifying the filename.
+       *  @param  __mode  Open file in specified mode (see std::ios_base).
+       *
+       *  @c ios_base::out is automatically included in @a __mode.
+       */
+      template<typename _Path, typename _Require = _If_fs_path<_Path>>
+	basic_ofstream(const _Path& __s,
+		       ios_base::openmode __mode = ios_base::out)
+	: basic_ofstream(__s.c_str(), __mode)
+	{ }
+#endif // C++17
+
+      basic_ofstream(const basic_ofstream&) = delete;
+
+      basic_ofstream(basic_ofstream&& __rhs)
+      : __ostream_type(std::move(__rhs)),
+      _M_filebuf(std::move(__rhs._M_filebuf))
+      { __ostream_type::set_rdbuf(&_M_filebuf); }
+#endif
+
+      /**
+       *  @brief  The destructor does nothing.
+       *
+       *  The file is closed by the filebuf object, not the formatting
+       *  stream.
+       */
+      ~basic_ofstream()
+      { }
+
+#if __cplusplus >= 201103L
+      // 27.8.3.2 Assign and swap:
+
+      basic_ofstream&
+      operator=(const basic_ofstream&) = delete;
+
+      basic_ofstream&
+      operator=(basic_ofstream&& __rhs)
+      {
+	__ostream_type::operator=(std::move(__rhs));
+	_M_filebuf = std::move(__rhs._M_filebuf);
+	return *this;
+      }
+
+      void
+      swap(basic_ofstream& __rhs)
+      {
+	__ostream_type::swap(__rhs);
+	_M_filebuf.swap(__rhs._M_filebuf);
+      }
+#endif
+
+      // Members:
+      /**
+       *  @brief  Accessing the underlying buffer.
+       *  @return  The current basic_filebuf buffer.
+       *
+       *  This hides both signatures of std::basic_ios::rdbuf().
+       */
+      __filebuf_type*
+      rdbuf() const
+      { return const_cast<__filebuf_type*>(&_M_filebuf); }
+
+      /**
+       *  @brief  Wrapper to test for an open file.
+       *  @return  @c rdbuf()->is_open()
+       */
+      bool
+      is_open()
+      { return _M_filebuf.is_open(); }
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 365. Lack of const-qualification in clause 27
+      bool
+      is_open() const
+      { return _M_filebuf.is_open(); }
+
+      /**
+       *  @brief  Opens an external file.
+       *  @param  __s  The name of the file.
+       *  @param  __mode  The open mode flags.
+       *
+       *  Calls @c std::basic_filebuf::open(__s,__mode|out).  If that
+       *  function fails, @c failbit is set in the stream's error state.
+       */
+      void
+      open(const char* __s, ios_base::openmode __mode = ios_base::out)
+      {
+	if (!_M_filebuf.open(__s, __mode | ios_base::out))
+	  this->setstate(ios_base::failbit);
+	else
+	  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+	  // 409. Closing an fstream should clear error state
+	  this->clear();
+      }
+
+#if _GLIBCXX_HAVE__WFOPEN && _GLIBCXX_USE_WCHAR_T
+      /**
+       *  @brief  Opens an external file.
+       *  @param  __s  The name of the file.
+       *  @param  __mode  The open mode flags.
+       *
+       *  Calls @c std::basic_filebuf::open(__s,__mode|out).  If that
+       *  function fails, @c failbit is set in the stream's error state.
+       */
+      void
+      open(const wchar_t* __s, ios_base::openmode __mode = ios_base::out)
+      {
+	if (!_M_filebuf.open(__s, __mode | ios_base::out))
+	  this->setstate(ios_base::failbit);
+	else
+	  this->clear();
+      }
+#endif
+
+#if __cplusplus >= 201103L
+      /**
+       *  @brief  Opens an external file.
+       *  @param  __s  The name of the file.
+       *  @param  __mode  The open mode flags.
+       *
+       *  Calls @c std::basic_filebuf::open(s,mode|out).  If that
+       *  function fails, @c failbit is set in the stream's error state.
+       */
+      void
+      open(const std::string& __s, ios_base::openmode __mode = ios_base::out)
+      {
+	if (!_M_filebuf.open(__s, __mode | ios_base::out))
+	  this->setstate(ios_base::failbit);
+	else
+	  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+	  // 409. Closing an fstream should clear error state
+	  this->clear();
+      }
+
+#if __cplusplus >= 201703L
+      /**
+       *  @brief  Opens an external file.
+       *  @param  __s  The name of the file, as a filesystem::path.
+       *  @param  __mode  The open mode flags.
+       *
+       *  Calls @c std::basic_filebuf::open(__s,__mode|out).  If that
+       *  function fails, @c failbit is set in the stream's error state.
+       */
+      template<typename _Path>
+	_If_fs_path<_Path, void>
+	open(const _Path& __s, ios_base::openmode __mode = ios_base::out)
+	{ open(__s.c_str(), __mode); }
+#endif // C++17
+#endif // C++11
+
+      /**
+       *  @brief  Close the file.
+       *
+       *  Calls @c std::basic_filebuf::close().  If that function
+       *  fails, @c failbit is set in the stream's error state.
+       */
+      void
+      close()
+      {
+	if (!_M_filebuf.close())
+	  this->setstate(ios_base::failbit);
+      }
+    };
+
+
+  // [27.8.1.11] Template class basic_fstream
+  /**
+   *  @brief  Controlling input and output for files.
+   *  @ingroup io
+   *
+   *  @tparam _CharT  Type of character stream.
+   *  @tparam _Traits  Traits for character type, defaults to
+   *                   char_traits<_CharT>.
+   *
+   *  This class supports reading from and writing to named files, using
+   *  the inherited functions from std::basic_iostream.  To control the
+   *  associated sequence, an instance of std::basic_filebuf is used, which
+   *  this page refers to as @c sb.
+   */
+  template<typename _CharT, typename _Traits>
+    class basic_fstream : public basic_iostream<_CharT, _Traits>
+    {
+    public:
+      // Types:
+      typedef _CharT 					char_type;
+      typedef _Traits 					traits_type;
+      typedef typename traits_type::int_type 		int_type;
+      typedef typename traits_type::pos_type 		pos_type;
+      typedef typename traits_type::off_type 		off_type;
+
+      // Non-standard types:
+      typedef basic_filebuf<char_type, traits_type> 	__filebuf_type;
+      typedef basic_ios<char_type, traits_type>		__ios_type;
+      typedef basic_iostream<char_type, traits_type>	__iostream_type;
+
+    private:
+      __filebuf_type	_M_filebuf;
+
+    public:
+      // Constructors/destructor:
+      /**
+       *  @brief  Default constructor.
+       *
+       *  Initializes @c sb using its default constructor, and passes
+       *  @c &sb to the base class initializer.  Does not open any files
+       *  (you haven't given it a filename to open).
+       */
+      basic_fstream()
+      : __iostream_type(), _M_filebuf()
+      { this->init(&_M_filebuf); }
+
+      /**
+       *  @brief  Create an input/output file stream.
+       *  @param  __s  Null terminated string specifying the filename.
+       *  @param  __mode  Open file in specified mode (see std::ios_base).
+       */
+      explicit
+      basic_fstream(const char* __s,
+		    ios_base::openmode __mode = ios_base::in | ios_base::out)
+      : __iostream_type(0), _M_filebuf()
+      {
+	this->init(&_M_filebuf);
+	this->open(__s, __mode);
+      }
+
+#if _GLIBCXX_HAVE__WFOPEN && _GLIBCXX_USE_WCHAR_T
+      /**
+       *  @param  Create an input/output file stream.
+       *  @param  __s  Wide string specifying the filename.
+       *  @param  __mode  Open file in specified mode (see std::ios_base).
+       */
+      basic_fstream(const wchar_t* __s,
+		    ios_base::openmode __mode = ios_base::in | ios_base::out)
+      : __iostream_type(0), _M_filebuf()
+      {
+	this->init(&_M_filebuf);
+	this->open(__s, __mode);
+      }
+#endif
+
+#if __cplusplus >= 201103L
+      /**
+       *  @brief  Create an input/output file stream.
+       *  @param  __s  Null terminated string specifying the filename.
+       *  @param  __mode  Open file in specified mode (see std::ios_base).
+       */
+      explicit
+      basic_fstream(const std::string& __s,
+		    ios_base::openmode __mode = ios_base::in | ios_base::out)
+      : __iostream_type(0), _M_filebuf()
+      {
+	this->init(&_M_filebuf);
+	this->open(__s, __mode);
+      }
+
+#if __cplusplus >= 201703L
+      /**
+       *  @brief  Create an input/output file stream.
+       *  @param  __s  filesystem::path specifying the filename.
+       *  @param  __mode  Open file in specified mode (see std::ios_base).
+       */
+      template<typename _Path, typename _Require = _If_fs_path<_Path>>
+	basic_fstream(const _Path& __s,
+		      ios_base::openmode __mode = ios_base::in | ios_base::out)
+	: basic_fstream(__s.c_str(), __mode)
+	{ }
+#endif // C++17
+
+      basic_fstream(const basic_fstream&) = delete;
+
+      basic_fstream(basic_fstream&& __rhs)
+      : __iostream_type(std::move(__rhs)),
+      _M_filebuf(std::move(__rhs._M_filebuf))
+      { __iostream_type::set_rdbuf(&_M_filebuf); }
+#endif
+
+      /**
+       *  @brief  The destructor does nothing.
+       *
+       *  The file is closed by the filebuf object, not the formatting
+       *  stream.
+       */
+      ~basic_fstream()
+      { }
+
+#if __cplusplus >= 201103L
+      // 27.8.3.2 Assign and swap:
+
+      basic_fstream&
+      operator=(const basic_fstream&) = delete;
+
+      basic_fstream&
+      operator=(basic_fstream&& __rhs)
+      {
+	__iostream_type::operator=(std::move(__rhs));
+	_M_filebuf = std::move(__rhs._M_filebuf);
+	return *this;
+      }
+
+      void
+      swap(basic_fstream& __rhs)
+      {
+	__iostream_type::swap(__rhs);
+	_M_filebuf.swap(__rhs._M_filebuf);
+      }
+#endif
+
+      // Members:
+      /**
+       *  @brief  Accessing the underlying buffer.
+       *  @return  The current basic_filebuf buffer.
+       *
+       *  This hides both signatures of std::basic_ios::rdbuf().
+       */
+      __filebuf_type*
+      rdbuf() const
+      { return const_cast<__filebuf_type*>(&_M_filebuf); }
+
+      /**
+       *  @brief  Wrapper to test for an open file.
+       *  @return  @c rdbuf()->is_open()
+       */
+      bool
+      is_open()
+      { return _M_filebuf.is_open(); }
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 365. Lack of const-qualification in clause 27
+      bool
+      is_open() const
+      { return _M_filebuf.is_open(); }
+
+      /**
+       *  @brief  Opens an external file.
+       *  @param  __s  The name of the file.
+       *  @param  __mode  The open mode flags.
+       *
+       *  Calls @c std::basic_filebuf::open(__s,__mode).  If that
+       *  function fails, @c failbit is set in the stream's error state.
+       */
+      void
+      open(const char* __s,
+	   ios_base::openmode __mode = ios_base::in | ios_base::out)
+      {
+	if (!_M_filebuf.open(__s, __mode))
+	  this->setstate(ios_base::failbit);
+	else
+	  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+	  // 409. Closing an fstream should clear error state
+	  this->clear();
+      }
+
+#if _GLIBCXX_HAVE__WFOPEN && _GLIBCXX_USE_WCHAR_T
+      /**
+       *  @brief  Opens an external file.
+       *  @param  __s  The name of the file.
+       *  @param  __mode  The open mode flags.
+       *
+       *  Calls @c std::basic_filebuf::open(__s,__mode).  If that
+       *  function fails, @c failbit is set in the stream's error state.
+       */
+      void
+      open(const wchar_t* __s,
+	   ios_base::openmode __mode = ios_base::in | ios_base::out)
+      {
+	if (!_M_filebuf.open(__s, __mode))
+	  this->setstate(ios_base::failbit);
+	else
+	  this->clear();
+      }
+#endif
+
+#if __cplusplus >= 201103L
+      /**
+       *  @brief  Opens an external file.
+       *  @param  __s  The name of the file.
+       *  @param  __mode  The open mode flags.
+       *
+       *  Calls @c std::basic_filebuf::open(__s,__mode).  If that
+       *  function fails, @c failbit is set in the stream's error state.
+       */
+      void
+      open(const std::string& __s,
+	   ios_base::openmode __mode = ios_base::in | ios_base::out)
+      {
+	if (!_M_filebuf.open(__s, __mode))
+	  this->setstate(ios_base::failbit);
+	else
+	  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+	  // 409. Closing an fstream should clear error state
+	  this->clear();
+      }
+
+#if __cplusplus >= 201703L
+      /**
+       *  @brief  Opens an external file.
+       *  @param  __s  The name of the file, as a filesystem::path.
+       *  @param  __mode  The open mode flags.
+       *
+       *  Calls @c std::basic_filebuf::open(__s,__mode).  If that
+       *  function fails, @c failbit is set in the stream's error state.
+       */
+      template<typename _Path>
+	_If_fs_path<_Path, void>
+	open(const _Path& __s,
+	     ios_base::openmode __mode = ios_base::in | ios_base::out)
+	{ open(__s.c_str(), __mode); }
+#endif // C++17
+#endif // C++11
+
+      /**
+       *  @brief  Close the file.
+       *
+       *  Calls @c std::basic_filebuf::close().  If that function
+       *  fails, @c failbit is set in the stream's error state.
+       */
+      void
+      close()
+      {
+	if (!_M_filebuf.close())
+	  this->setstate(ios_base::failbit);
+      }
+    };
+
+#if __cplusplus >= 201103L
+  /// Swap specialization for filebufs.
+  template <class _CharT, class _Traits>
+    inline void
+    swap(basic_filebuf<_CharT, _Traits>& __x,
+	 basic_filebuf<_CharT, _Traits>& __y)
+    { __x.swap(__y); }
+
+  /// Swap specialization for ifstreams.
+  template <class _CharT, class _Traits>
+    inline void
+    swap(basic_ifstream<_CharT, _Traits>& __x,
+	 basic_ifstream<_CharT, _Traits>& __y)
+    { __x.swap(__y); }
+
+  /// Swap specialization for ofstreams.
+  template <class _CharT, class _Traits>
+    inline void
+    swap(basic_ofstream<_CharT, _Traits>& __x,
+	 basic_ofstream<_CharT, _Traits>& __y)
+    { __x.swap(__y); }
+
+  /// Swap specialization for fstreams.
+  template <class _CharT, class _Traits>
+    inline void
+    swap(basic_fstream<_CharT, _Traits>& __x,
+	 basic_fstream<_CharT, _Traits>& __y)
+    { __x.swap(__y); }
+#endif
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#include <bits/fstream.tcc>
+
+#endif /* _GLIBCXX_FSTREAM */
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@@ -0,0 +1,1370 @@
+// <functional> -*- C++ -*-
+
+// Copyright (C) 2001-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/*
+ * Copyright (c) 1997
+ * Silicon Graphics Computer Systems, Inc.
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Silicon Graphics makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ *
+ */
+
+/** @file include/functional
+ *  This is a Standard C++ Library header.
+ */
+
+#ifndef _GLIBCXX_FUNCTIONAL
+#define _GLIBCXX_FUNCTIONAL 1
+
+#pragma GCC system_header
+
+#include <bits/c++config.h>
+#include <bits/stl_function.h>
+
+#if __cplusplus >= 201103L
+
+#include <new>
+#include <tuple>
+#include <type_traits>
+#include <bits/functional_hash.h>
+#include <bits/invoke.h>
+#include <bits/refwrap.h>	// std::reference_wrapper and _Mem_fn_traits
+#include <bits/std_function.h>	// std::function
+#if __cplusplus > 201402L
+# include <unordered_map>
+# include <vector>
+# include <array>
+# include <bits/stl_algo.h>
+#endif
+#if __cplusplus > 201703L
+# include <bits/ranges_cmp.h>
+# include <compare>
+#endif
+#if __cplusplus > 202002L
+# include <bits/move_only_function.h>
+#endif
+
+#endif // C++11
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /** @brief The type of placeholder objects defined by libstdc++.
+   *  @ingroup binders
+   *  @since C++11
+   */
+  template<int _Num> struct _Placeholder { };
+
+#if __cplusplus >= 201103L
+
+#if __cplusplus >= 201703L
+# define __cpp_lib_invoke 201411L
+# if __cplusplus > 201703L
+#  define __cpp_lib_constexpr_functional 201907L
+# endif
+
+  /** Invoke a callable object.
+   *
+   * `std::invoke` takes a callable object as its first argument and calls it
+   * with the remaining arguments. The callable object can be a pointer or
+   * reference to a function, a lambda closure, a class with `operator()`,
+   * or even a pointer-to-member.  For a pointer-to-member the first argument
+   * must be a reference or pointer to the object that the pointer-to-member
+   * will be applied to.
+   *
+   *  @since C++17
+   */
+  template<typename _Callable, typename... _Args>
+    inline _GLIBCXX20_CONSTEXPR invoke_result_t<_Callable, _Args...>
+    invoke(_Callable&& __fn, _Args&&... __args)
+    noexcept(is_nothrow_invocable_v<_Callable, _Args...>)
+    {
+      return std::__invoke(std::forward<_Callable>(__fn),
+			   std::forward<_Args>(__args)...);
+    }
+
+#if __cplusplus > 202002L
+# define __cpp_lib_invoke_r 202106L
+
+  /** Invoke a callable object and convert the result to `_Res`.
+   *
+   * `std::invoke_r<R>(f, args...)` is equivalent to `std::invoke(f, args...)`
+   * with the result implicitly converted to `R`.
+   *
+   *  @since C++23
+   */
+  template<typename _Res, typename _Callable, typename... _Args>
+    requires is_invocable_r_v<_Res, _Callable, _Args...>
+    constexpr _Res
+    invoke_r(_Callable&& __fn, _Args&&... __args)
+    noexcept(is_nothrow_invocable_r_v<_Res, _Callable, _Args...>)
+    {
+      return std::__invoke_r<_Res>(std::forward<_Callable>(__fn),
+				   std::forward<_Args>(__args)...);
+    }
+#endif // C++23
+#endif // C++17
+
+  /// @cond undocumented
+
+  template<typename _MemFunPtr,
+	   bool __is_mem_fn = is_member_function_pointer<_MemFunPtr>::value>
+    class _Mem_fn_base
+    : public _Mem_fn_traits<_MemFunPtr>::__maybe_type
+    {
+      using _Traits = _Mem_fn_traits<_MemFunPtr>;
+
+      using _Arity = typename _Traits::__arity;
+      using _Varargs = typename _Traits::__vararg;
+
+      template<typename _Func, typename... _BoundArgs>
+	friend struct _Bind_check_arity;
+
+      _MemFunPtr _M_pmf;
+
+    public:
+
+      using result_type = typename _Traits::__result_type;
+
+      explicit constexpr
+      _Mem_fn_base(_MemFunPtr __pmf) noexcept : _M_pmf(__pmf) { }
+
+      template<typename... _Args>
+	_GLIBCXX20_CONSTEXPR
+	auto
+	operator()(_Args&&... __args) const
+	noexcept(noexcept(
+	      std::__invoke(_M_pmf, std::forward<_Args>(__args)...)))
+	-> decltype(std::__invoke(_M_pmf, std::forward<_Args>(__args)...))
+	{ return std::__invoke(_M_pmf, std::forward<_Args>(__args)...); }
+    };
+
+  // Partial specialization for member object pointers.
+  template<typename _MemObjPtr>
+    class _Mem_fn_base<_MemObjPtr, false>
+    {
+      using _Arity = integral_constant<size_t, 0>;
+      using _Varargs = false_type;
+
+      template<typename _Func, typename... _BoundArgs>
+	friend struct _Bind_check_arity;
+
+      _MemObjPtr _M_pm;
+
+    public:
+      explicit constexpr
+      _Mem_fn_base(_MemObjPtr __pm) noexcept : _M_pm(__pm) { }
+
+      template<typename _Tp>
+	_GLIBCXX20_CONSTEXPR
+	auto
+	operator()(_Tp&& __obj) const
+	noexcept(noexcept(std::__invoke(_M_pm, std::forward<_Tp>(__obj))))
+	-> decltype(std::__invoke(_M_pm, std::forward<_Tp>(__obj)))
+	{ return std::__invoke(_M_pm, std::forward<_Tp>(__obj)); }
+    };
+
+  template<typename _MemberPointer>
+    struct _Mem_fn; // undefined
+
+  template<typename _Res, typename _Class>
+    struct _Mem_fn<_Res _Class::*>
+    : _Mem_fn_base<_Res _Class::*>
+    {
+      using _Mem_fn_base<_Res _Class::*>::_Mem_fn_base;
+    };
+  /// @endcond
+
+  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+  // 2048.  Unnecessary mem_fn overloads
+  /**
+   * @brief Returns a function object that forwards to the member pointer
+   * pointer `pm`.
+   *
+   * This allows a pointer-to-member to be transformed into a function object
+   * that can be called with an object expression as its first argument.
+   *
+   * For a pointer-to-data-member the result must be called with exactly one
+   * argument, the object expression that would be used as the first operand
+   * in a `obj.*memptr` or `objp->*memptr` expression.
+   *
+   * For a pointer-to-member-function the result must be called with an object
+   * expression and any additional arguments to pass to the member function,
+   * as in an expression like `(obj.*memfun)(args...)` or
+   * `(objp->*memfun)(args...)`.
+   *
+   * The object expression can be a pointer, reference, `reference_wrapper`,
+   * or smart pointer, and the call wrapper will dereference it as needed
+   * to apply the pointer-to-member.
+   *
+   * @ingroup functors
+   * @since C++11
+   */
+  template<typename _Tp, typename _Class>
+    _GLIBCXX20_CONSTEXPR
+    inline _Mem_fn<_Tp _Class::*>
+    mem_fn(_Tp _Class::* __pm) noexcept
+    {
+      return _Mem_fn<_Tp _Class::*>(__pm);
+    }
+
+  /**
+   * @brief Trait that identifies a bind expression.
+   * 
+   * Determines if the given type `_Tp` is a function object that
+   * should be treated as a subexpression when evaluating calls to
+   * function objects returned by `std::bind`.
+   *
+   * C++11 [func.bind.isbind].
+   * @ingroup binders
+   * @since C++11
+   */
+  template<typename _Tp>
+    struct is_bind_expression
+    : public false_type { };
+
+  /**
+   *  @brief Determines if the given type _Tp is a placeholder in a
+   *  bind() expression and, if so, which placeholder it is.
+   *
+   *  C++11 [func.bind.isplace].
+   *  @ingroup binders
+   *  @since C++11
+   */
+  template<typename _Tp>
+    struct is_placeholder
+    : public integral_constant<int, 0>
+    { };
+
+#if __cplusplus > 201402L
+  template <typename _Tp> inline constexpr bool is_bind_expression_v
+    = is_bind_expression<_Tp>::value;
+  template <typename _Tp> inline constexpr int is_placeholder_v
+    = is_placeholder<_Tp>::value;
+#endif // C++17
+
+  /** @namespace std::placeholders
+   *  @brief ISO C++ 2011 namespace for std::bind placeholders.
+   *  @ingroup binders
+   *  @since C++11
+   */
+  namespace placeholders
+  {
+  /* Define a large number of placeholders. There is no way to
+   * simplify this with variadic templates, because we're introducing
+   * unique names for each.
+   */
+    extern const _Placeholder<1> _1;
+    extern const _Placeholder<2> _2;
+    extern const _Placeholder<3> _3;
+    extern const _Placeholder<4> _4;
+    extern const _Placeholder<5> _5;
+    extern const _Placeholder<6> _6;
+    extern const _Placeholder<7> _7;
+    extern const _Placeholder<8> _8;
+    extern const _Placeholder<9> _9;
+    extern const _Placeholder<10> _10;
+    extern const _Placeholder<11> _11;
+    extern const _Placeholder<12> _12;
+    extern const _Placeholder<13> _13;
+    extern const _Placeholder<14> _14;
+    extern const _Placeholder<15> _15;
+    extern const _Placeholder<16> _16;
+    extern const _Placeholder<17> _17;
+    extern const _Placeholder<18> _18;
+    extern const _Placeholder<19> _19;
+    extern const _Placeholder<20> _20;
+    extern const _Placeholder<21> _21;
+    extern const _Placeholder<22> _22;
+    extern const _Placeholder<23> _23;
+    extern const _Placeholder<24> _24;
+    extern const _Placeholder<25> _25;
+    extern const _Placeholder<26> _26;
+    extern const _Placeholder<27> _27;
+    extern const _Placeholder<28> _28;
+    extern const _Placeholder<29> _29;
+  }
+
+  /**
+   *  Partial specialization of is_placeholder that provides the placeholder
+   *  number for the placeholder objects defined by libstdc++.
+   *  @ingroup binders
+   *  @since C++11
+   */
+  template<int _Num>
+    struct is_placeholder<_Placeholder<_Num> >
+    : public integral_constant<int, _Num>
+    { };
+
+  template<int _Num>
+    struct is_placeholder<const _Placeholder<_Num> >
+    : public integral_constant<int, _Num>
+    { };
+
+  /// @cond undocumented
+
+  // Like tuple_element_t but SFINAE-friendly.
+  template<std::size_t __i, typename _Tuple>
+    using _Safe_tuple_element_t
+      = typename enable_if<(__i < tuple_size<_Tuple>::value),
+			   tuple_element<__i, _Tuple>>::type::type;
+
+  /**
+   *  Maps an argument to bind() into an actual argument to the bound
+   *  function object [func.bind.bind]/10. Only the first parameter should
+   *  be specified: the rest are used to determine among the various
+   *  implementations. Note that, although this class is a function
+   *  object, it isn't entirely normal because it takes only two
+   *  parameters regardless of the number of parameters passed to the
+   *  bind expression. The first parameter is the bound argument and
+   *  the second parameter is a tuple containing references to the
+   *  rest of the arguments.
+   */
+  template<typename _Arg,
+	   bool _IsBindExp = is_bind_expression<_Arg>::value,
+	   bool _IsPlaceholder = (is_placeholder<_Arg>::value > 0)>
+    class _Mu;
+
+  /**
+   *  If the argument is reference_wrapper<_Tp>, returns the
+   *  underlying reference.
+   *  C++11 [func.bind.bind] p10 bullet 1.
+   */
+  template<typename _Tp>
+    class _Mu<reference_wrapper<_Tp>, false, false>
+    {
+    public:
+      /* Note: This won't actually work for const volatile
+       * reference_wrappers, because reference_wrapper::get() is const
+       * but not volatile-qualified. This might be a defect in the TR.
+       */
+      template<typename _CVRef, typename _Tuple>
+	_GLIBCXX20_CONSTEXPR
+	_Tp&
+	operator()(_CVRef& __arg, _Tuple&) const volatile
+	{ return __arg.get(); }
+    };
+
+  /**
+   *  If the argument is a bind expression, we invoke the underlying
+   *  function object with the same cv-qualifiers as we are given and
+   *  pass along all of our arguments (unwrapped).
+   *  C++11 [func.bind.bind] p10 bullet 2.
+   */
+  template<typename _Arg>
+    class _Mu<_Arg, true, false>
+    {
+    public:
+      template<typename _CVArg, typename... _Args>
+	_GLIBCXX20_CONSTEXPR
+	auto
+	operator()(_CVArg& __arg,
+		   tuple<_Args...>& __tuple) const volatile
+	-> decltype(__arg(declval<_Args>()...))
+	{
+	  // Construct an index tuple and forward to __call
+	  typedef typename _Build_index_tuple<sizeof...(_Args)>::__type
+	    _Indexes;
+	  return this->__call(__arg, __tuple, _Indexes());
+	}
+
+    private:
+      // Invokes the underlying function object __arg by unpacking all
+      // of the arguments in the tuple.
+      template<typename _CVArg, typename... _Args, std::size_t... _Indexes>
+	_GLIBCXX20_CONSTEXPR
+	auto
+	__call(_CVArg& __arg, tuple<_Args...>& __tuple,
+	       const _Index_tuple<_Indexes...>&) const volatile
+	-> decltype(__arg(declval<_Args>()...))
+	{
+	  return __arg(std::get<_Indexes>(std::move(__tuple))...);
+	}
+    };
+
+  /**
+   *  If the argument is a placeholder for the Nth argument, returns
+   *  a reference to the Nth argument to the bind function object.
+   *  C++11 [func.bind.bind] p10 bullet 3.
+   */
+  template<typename _Arg>
+    class _Mu<_Arg, false, true>
+    {
+    public:
+      template<typename _Tuple>
+	_GLIBCXX20_CONSTEXPR
+	_Safe_tuple_element_t<(is_placeholder<_Arg>::value - 1), _Tuple>&&
+	operator()(const volatile _Arg&, _Tuple& __tuple) const volatile
+	{
+	  return
+	    ::std::get<(is_placeholder<_Arg>::value - 1)>(std::move(__tuple));
+	}
+    };
+
+  /**
+   *  If the argument is just a value, returns a reference to that
+   *  value. The cv-qualifiers on the reference are determined by the caller.
+   *  C++11 [func.bind.bind] p10 bullet 4.
+   */
+  template<typename _Arg>
+    class _Mu<_Arg, false, false>
+    {
+    public:
+      template<typename _CVArg, typename _Tuple>
+	_GLIBCXX20_CONSTEXPR
+	_CVArg&&
+	operator()(_CVArg&& __arg, _Tuple&) const volatile
+	{ return std::forward<_CVArg>(__arg); }
+    };
+
+  // std::get<I> for volatile-qualified tuples
+  template<std::size_t _Ind, typename... _Tp>
+    inline auto
+    __volget(volatile tuple<_Tp...>& __tuple)
+    -> __tuple_element_t<_Ind, tuple<_Tp...>> volatile&
+    { return std::get<_Ind>(const_cast<tuple<_Tp...>&>(__tuple)); }
+
+  // std::get<I> for const-volatile-qualified tuples
+  template<std::size_t _Ind, typename... _Tp>
+    inline auto
+    __volget(const volatile tuple<_Tp...>& __tuple)
+    -> __tuple_element_t<_Ind, tuple<_Tp...>> const volatile&
+    { return std::get<_Ind>(const_cast<const tuple<_Tp...>&>(__tuple)); }
+
+  /// @endcond
+
+  /// Type of the function object returned from bind().
+  template<typename _Signature>
+    class _Bind;
+
+   template<typename _Functor, typename... _Bound_args>
+    class _Bind<_Functor(_Bound_args...)>
+    : public _Weak_result_type<_Functor>
+    {
+      typedef typename _Build_index_tuple<sizeof...(_Bound_args)>::__type
+	_Bound_indexes;
+
+      _Functor _M_f;
+      tuple<_Bound_args...> _M_bound_args;
+
+      // Call unqualified
+      template<typename _Result, typename... _Args, std::size_t... _Indexes>
+	_GLIBCXX20_CONSTEXPR
+	_Result
+	__call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>)
+	{
+	  return std::__invoke(_M_f,
+	      _Mu<_Bound_args>()(std::get<_Indexes>(_M_bound_args), __args)...
+	      );
+	}
+
+      // Call as const
+      template<typename _Result, typename... _Args, std::size_t... _Indexes>
+	_GLIBCXX20_CONSTEXPR
+	_Result
+	__call_c(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>) const
+	{
+	  return std::__invoke(_M_f,
+	      _Mu<_Bound_args>()(std::get<_Indexes>(_M_bound_args), __args)...
+	      );
+	}
+
+      // Call as volatile
+      template<typename _Result, typename... _Args, std::size_t... _Indexes>
+	_Result
+	__call_v(tuple<_Args...>&& __args,
+		 _Index_tuple<_Indexes...>) volatile
+	{
+	  return std::__invoke(_M_f,
+	      _Mu<_Bound_args>()(__volget<_Indexes>(_M_bound_args), __args)...
+	      );
+	}
+
+      // Call as const volatile
+      template<typename _Result, typename... _Args, std::size_t... _Indexes>
+	_Result
+	__call_c_v(tuple<_Args...>&& __args,
+		   _Index_tuple<_Indexes...>) const volatile
+	{
+	  return std::__invoke(_M_f,
+	      _Mu<_Bound_args>()(__volget<_Indexes>(_M_bound_args), __args)...
+	      );
+	}
+
+      template<typename _BoundArg, typename _CallArgs>
+	using _Mu_type = decltype(
+	    _Mu<typename remove_cv<_BoundArg>::type>()(
+	      std::declval<_BoundArg&>(), std::declval<_CallArgs&>()) );
+
+      template<typename _Fn, typename _CallArgs, typename... _BArgs>
+	using _Res_type_impl
+	  = typename result_of< _Fn&(_Mu_type<_BArgs, _CallArgs>&&...) >::type;
+
+      template<typename _CallArgs>
+	using _Res_type = _Res_type_impl<_Functor, _CallArgs, _Bound_args...>;
+
+      template<typename _CallArgs>
+	using __dependent = typename
+	  enable_if<bool(tuple_size<_CallArgs>::value+1), _Functor>::type;
+
+      template<typename _CallArgs, template<class> class __cv_quals>
+	using _Res_type_cv = _Res_type_impl<
+	  typename __cv_quals<__dependent<_CallArgs>>::type,
+	  _CallArgs,
+	  typename __cv_quals<_Bound_args>::type...>;
+
+     public:
+      template<typename... _Args>
+	explicit _GLIBCXX20_CONSTEXPR
+	_Bind(const _Functor& __f, _Args&&... __args)
+	: _M_f(__f), _M_bound_args(std::forward<_Args>(__args)...)
+	{ }
+
+      template<typename... _Args>
+	explicit _GLIBCXX20_CONSTEXPR
+	_Bind(_Functor&& __f, _Args&&... __args)
+	: _M_f(std::move(__f)), _M_bound_args(std::forward<_Args>(__args)...)
+	{ }
+
+      _Bind(const _Bind&) = default;
+      _Bind(_Bind&&) = default;
+
+      // Call unqualified
+      template<typename... _Args,
+	       typename _Result = _Res_type<tuple<_Args...>>>
+	_GLIBCXX20_CONSTEXPR
+	_Result
+	operator()(_Args&&... __args)
+	{
+	  return this->__call<_Result>(
+	      std::forward_as_tuple(std::forward<_Args>(__args)...),
+	      _Bound_indexes());
+	}
+
+      // Call as const
+      template<typename... _Args,
+	       typename _Result = _Res_type_cv<tuple<_Args...>, add_const>>
+	_GLIBCXX20_CONSTEXPR
+	_Result
+	operator()(_Args&&... __args) const
+	{
+	  return this->__call_c<_Result>(
+	      std::forward_as_tuple(std::forward<_Args>(__args)...),
+	      _Bound_indexes());
+	}
+
+#if __cplusplus > 201402L
+# define _GLIBCXX_DEPR_BIND \
+      [[deprecated("std::bind does not support volatile in C++17")]]
+#else
+# define _GLIBCXX_DEPR_BIND
+#endif
+      // Call as volatile
+      template<typename... _Args,
+	       typename _Result = _Res_type_cv<tuple<_Args...>, add_volatile>>
+	_GLIBCXX_DEPR_BIND
+	_Result
+	operator()(_Args&&... __args) volatile
+	{
+	  return this->__call_v<_Result>(
+	      std::forward_as_tuple(std::forward<_Args>(__args)...),
+	      _Bound_indexes());
+	}
+
+      // Call as const volatile
+      template<typename... _Args,
+	       typename _Result = _Res_type_cv<tuple<_Args...>, add_cv>>
+	_GLIBCXX_DEPR_BIND
+	_Result
+	operator()(_Args&&... __args) const volatile
+	{
+	  return this->__call_c_v<_Result>(
+	      std::forward_as_tuple(std::forward<_Args>(__args)...),
+	      _Bound_indexes());
+	}
+    };
+
+  /// Type of the function object returned from bind<R>().
+  template<typename _Result, typename _Signature>
+    class _Bind_result;
+
+  template<typename _Result, typename _Functor, typename... _Bound_args>
+    class _Bind_result<_Result, _Functor(_Bound_args...)>
+    {
+      typedef typename _Build_index_tuple<sizeof...(_Bound_args)>::__type
+	_Bound_indexes;
+
+      _Functor _M_f;
+      tuple<_Bound_args...> _M_bound_args;
+
+      // Call unqualified
+      template<typename _Res, typename... _Args, std::size_t... _Indexes>
+	_GLIBCXX20_CONSTEXPR
+	_Res
+	__call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>)
+	{
+	  return std::__invoke_r<_Res>(_M_f, _Mu<_Bound_args>()
+		      (std::get<_Indexes>(_M_bound_args), __args)...);
+	}
+
+      // Call as const
+      template<typename _Res, typename... _Args, std::size_t... _Indexes>
+	_GLIBCXX20_CONSTEXPR
+	_Res
+	__call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>) const
+	{
+	  return std::__invoke_r<_Res>(_M_f, _Mu<_Bound_args>()
+		      (std::get<_Indexes>(_M_bound_args), __args)...);
+	}
+
+      // Call as volatile
+      template<typename _Res, typename... _Args, std::size_t... _Indexes>
+	_GLIBCXX20_CONSTEXPR
+	_Res
+	__call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>) volatile
+	{
+	  return std::__invoke_r<_Res>(_M_f, _Mu<_Bound_args>()
+		      (__volget<_Indexes>(_M_bound_args), __args)...);
+	}
+
+      // Call as const volatile
+      template<typename _Res, typename... _Args, std::size_t... _Indexes>
+	_GLIBCXX20_CONSTEXPR
+	_Res
+	__call(tuple<_Args...>&& __args,
+	       _Index_tuple<_Indexes...>) const volatile
+	{
+	  return std::__invoke_r<_Res>(_M_f, _Mu<_Bound_args>()
+		      (__volget<_Indexes>(_M_bound_args), __args)...);
+	}
+
+    public:
+      typedef _Result result_type;
+
+      template<typename... _Args>
+	explicit _GLIBCXX20_CONSTEXPR
+	_Bind_result(const _Functor& __f, _Args&&... __args)
+	: _M_f(__f), _M_bound_args(std::forward<_Args>(__args)...)
+	{ }
+
+      template<typename... _Args>
+	explicit _GLIBCXX20_CONSTEXPR
+	_Bind_result(_Functor&& __f, _Args&&... __args)
+	: _M_f(std::move(__f)), _M_bound_args(std::forward<_Args>(__args)...)
+	{ }
+
+      _Bind_result(const _Bind_result&) = default;
+      _Bind_result(_Bind_result&&) = default;
+
+      // Call unqualified
+      template<typename... _Args>
+	_GLIBCXX20_CONSTEXPR
+	result_type
+	operator()(_Args&&... __args)
+	{
+	  return this->__call<_Result>(
+	      std::forward_as_tuple(std::forward<_Args>(__args)...),
+	      _Bound_indexes());
+	}
+
+      // Call as const
+      template<typename... _Args>
+	_GLIBCXX20_CONSTEXPR
+	result_type
+	operator()(_Args&&... __args) const
+	{
+	  return this->__call<_Result>(
+	      std::forward_as_tuple(std::forward<_Args>(__args)...),
+	      _Bound_indexes());
+	}
+
+      // Call as volatile
+      template<typename... _Args>
+	_GLIBCXX_DEPR_BIND
+	result_type
+	operator()(_Args&&... __args) volatile
+	{
+	  return this->__call<_Result>(
+	      std::forward_as_tuple(std::forward<_Args>(__args)...),
+	      _Bound_indexes());
+	}
+
+      // Call as const volatile
+      template<typename... _Args>
+	_GLIBCXX_DEPR_BIND
+	result_type
+	operator()(_Args&&... __args) const volatile
+	{
+	  return this->__call<_Result>(
+	      std::forward_as_tuple(std::forward<_Args>(__args)...),
+	      _Bound_indexes());
+	}
+    };
+#undef _GLIBCXX_DEPR_BIND
+
+  /**
+   *  @brief Class template _Bind is always a bind expression.
+   *  @ingroup binders
+   */
+  template<typename _Signature>
+    struct is_bind_expression<_Bind<_Signature> >
+    : public true_type { };
+
+  /**
+   *  @brief Class template _Bind is always a bind expression.
+   *  @ingroup binders
+   */
+  template<typename _Signature>
+    struct is_bind_expression<const _Bind<_Signature> >
+    : public true_type { };
+
+  /**
+   *  @brief Class template _Bind is always a bind expression.
+   *  @ingroup binders
+   */
+  template<typename _Signature>
+    struct is_bind_expression<volatile _Bind<_Signature> >
+    : public true_type { };
+
+  /**
+   *  @brief Class template _Bind is always a bind expression.
+   *  @ingroup binders
+   */
+  template<typename _Signature>
+    struct is_bind_expression<const volatile _Bind<_Signature>>
+    : public true_type { };
+
+  /**
+   *  @brief Class template _Bind_result is always a bind expression.
+   *  @ingroup binders
+   */
+  template<typename _Result, typename _Signature>
+    struct is_bind_expression<_Bind_result<_Result, _Signature>>
+    : public true_type { };
+
+  /**
+   *  @brief Class template _Bind_result is always a bind expression.
+   *  @ingroup binders
+   */
+  template<typename _Result, typename _Signature>
+    struct is_bind_expression<const _Bind_result<_Result, _Signature>>
+    : public true_type { };
+
+  /**
+   *  @brief Class template _Bind_result is always a bind expression.
+   *  @ingroup binders
+   */
+  template<typename _Result, typename _Signature>
+    struct is_bind_expression<volatile _Bind_result<_Result, _Signature>>
+    : public true_type { };
+
+  /**
+   *  @brief Class template _Bind_result is always a bind expression.
+   *  @ingroup binders
+   */
+  template<typename _Result, typename _Signature>
+    struct is_bind_expression<const volatile _Bind_result<_Result, _Signature>>
+    : public true_type { };
+
+  template<typename _Func, typename... _BoundArgs>
+    struct _Bind_check_arity { };
+
+  template<typename _Ret, typename... _Args, typename... _BoundArgs>
+    struct _Bind_check_arity<_Ret (*)(_Args...), _BoundArgs...>
+    {
+      static_assert(sizeof...(_BoundArgs) == sizeof...(_Args),
+                   "Wrong number of arguments for function");
+    };
+
+  template<typename _Ret, typename... _Args, typename... _BoundArgs>
+    struct _Bind_check_arity<_Ret (*)(_Args......), _BoundArgs...>
+    {
+      static_assert(sizeof...(_BoundArgs) >= sizeof...(_Args),
+                   "Wrong number of arguments for function");
+    };
+
+  template<typename _Tp, typename _Class, typename... _BoundArgs>
+    struct _Bind_check_arity<_Tp _Class::*, _BoundArgs...>
+    {
+      using _Arity = typename _Mem_fn<_Tp _Class::*>::_Arity;
+      using _Varargs = typename _Mem_fn<_Tp _Class::*>::_Varargs;
+      static_assert(_Varargs::value
+		    ? sizeof...(_BoundArgs) >= _Arity::value + 1
+		    : sizeof...(_BoundArgs) == _Arity::value + 1,
+		    "Wrong number of arguments for pointer-to-member");
+    };
+
+  // Trait type used to remove std::bind() from overload set via SFINAE
+  // when first argument has integer type, so that std::bind() will
+  // not be a better match than ::bind() from the BSD Sockets API.
+  template<typename _Tp, typename _Tp2 = typename decay<_Tp>::type>
+    using __is_socketlike = __or_<is_integral<_Tp2>, is_enum<_Tp2>>;
+
+  template<bool _SocketLike, typename _Func, typename... _BoundArgs>
+    struct _Bind_helper
+    : _Bind_check_arity<typename decay<_Func>::type, _BoundArgs...>
+    {
+      typedef typename decay<_Func>::type __func_type;
+      typedef _Bind<__func_type(typename decay<_BoundArgs>::type...)> type;
+    };
+
+  // Partial specialization for is_socketlike == true, does not define
+  // nested type so std::bind() will not participate in overload resolution
+  // when the first argument might be a socket file descriptor.
+  template<typename _Func, typename... _BoundArgs>
+    struct _Bind_helper<true, _Func, _BoundArgs...>
+    { };
+
+  /**
+   *  @brief Function template for std::bind.
+   *  @ingroup binders
+   *  @since C++11
+   */
+  template<typename _Func, typename... _BoundArgs>
+    inline _GLIBCXX20_CONSTEXPR typename
+    _Bind_helper<__is_socketlike<_Func>::value, _Func, _BoundArgs...>::type
+    bind(_Func&& __f, _BoundArgs&&... __args)
+    {
+      typedef _Bind_helper<false, _Func, _BoundArgs...> __helper_type;
+      return typename __helper_type::type(std::forward<_Func>(__f),
+					  std::forward<_BoundArgs>(__args)...);
+    }
+
+  template<typename _Result, typename _Func, typename... _BoundArgs>
+    struct _Bindres_helper
+    : _Bind_check_arity<typename decay<_Func>::type, _BoundArgs...>
+    {
+      typedef typename decay<_Func>::type __functor_type;
+      typedef _Bind_result<_Result,
+			   __functor_type(typename decay<_BoundArgs>::type...)>
+	type;
+    };
+
+  /**
+   *  @brief Function template for std::bind<R>.
+   *  @ingroup binders
+   *  @since C++11
+   */
+  template<typename _Result, typename _Func, typename... _BoundArgs>
+    inline _GLIBCXX20_CONSTEXPR
+    typename _Bindres_helper<_Result, _Func, _BoundArgs...>::type
+    bind(_Func&& __f, _BoundArgs&&... __args)
+    {
+      typedef _Bindres_helper<_Result, _Func, _BoundArgs...> __helper_type;
+      return typename __helper_type::type(std::forward<_Func>(__f),
+					  std::forward<_BoundArgs>(__args)...);
+    }
+
+#if __cplusplus > 201703L
+#define __cpp_lib_bind_front 201907L
+
+  template<typename _Fd, typename... _BoundArgs>
+    struct _Bind_front
+    {
+      static_assert(is_move_constructible_v<_Fd>);
+      static_assert((is_move_constructible_v<_BoundArgs> && ...));
+
+      // First parameter is to ensure this constructor is never used
+      // instead of the copy/move constructor.
+      template<typename _Fn, typename... _Args>
+	explicit constexpr
+	_Bind_front(int, _Fn&& __fn, _Args&&... __args)
+	noexcept(__and_<is_nothrow_constructible<_Fd, _Fn>,
+			is_nothrow_constructible<_BoundArgs, _Args>...>::value)
+	: _M_fd(std::forward<_Fn>(__fn)),
+	  _M_bound_args(std::forward<_Args>(__args)...)
+	{ static_assert(sizeof...(_Args) == sizeof...(_BoundArgs)); }
+
+      _Bind_front(const _Bind_front&) = default;
+      _Bind_front(_Bind_front&&) = default;
+      _Bind_front& operator=(const _Bind_front&) = default;
+      _Bind_front& operator=(_Bind_front&&) = default;
+      ~_Bind_front() = default;
+
+      template<typename... _CallArgs>
+	constexpr
+	invoke_result_t<_Fd&, _BoundArgs&..., _CallArgs...>
+	operator()(_CallArgs&&... __call_args) &
+	noexcept(is_nothrow_invocable_v<_Fd&, _BoundArgs&..., _CallArgs...>)
+	{
+	  return _S_call(*this, _BoundIndices(),
+	      std::forward<_CallArgs>(__call_args)...);
+	}
+
+      template<typename... _CallArgs>
+	constexpr
+	invoke_result_t<const _Fd&, const _BoundArgs&..., _CallArgs...>
+	operator()(_CallArgs&&... __call_args) const &
+	noexcept(is_nothrow_invocable_v<const _Fd&, const _BoundArgs&...,
+					_CallArgs...>)
+	{
+	  return _S_call(*this, _BoundIndices(),
+	      std::forward<_CallArgs>(__call_args)...);
+	}
+
+      template<typename... _CallArgs>
+	constexpr
+	invoke_result_t<_Fd, _BoundArgs..., _CallArgs...>
+	operator()(_CallArgs&&... __call_args) &&
+	noexcept(is_nothrow_invocable_v<_Fd, _BoundArgs..., _CallArgs...>)
+	{
+	  return _S_call(std::move(*this), _BoundIndices(),
+	      std::forward<_CallArgs>(__call_args)...);
+	}
+
+      template<typename... _CallArgs>
+	constexpr
+	invoke_result_t<const _Fd, const _BoundArgs..., _CallArgs...>
+	operator()(_CallArgs&&... __call_args) const &&
+	noexcept(is_nothrow_invocable_v<const _Fd, const _BoundArgs...,
+					_CallArgs...>)
+	{
+	  return _S_call(std::move(*this), _BoundIndices(),
+	      std::forward<_CallArgs>(__call_args)...);
+	}
+
+    private:
+      using _BoundIndices = index_sequence_for<_BoundArgs...>;
+
+      template<typename _Tp, size_t... _Ind, typename... _CallArgs>
+	static constexpr
+	decltype(auto)
+	_S_call(_Tp&& __g, index_sequence<_Ind...>, _CallArgs&&... __call_args)
+	{
+	  return std::invoke(std::forward<_Tp>(__g)._M_fd,
+	      std::get<_Ind>(std::forward<_Tp>(__g)._M_bound_args)...,
+	      std::forward<_CallArgs>(__call_args)...);
+	}
+
+      _Fd _M_fd;
+      std::tuple<_BoundArgs...> _M_bound_args;
+    };
+
+  template<typename _Fn, typename... _Args>
+    using _Bind_front_t
+      = _Bind_front<decay_t<_Fn>, decay_t<_Args>...>;
+
+  /** Create call wrapper by partial application of arguments to function.
+   *
+   * The result of `std::bind_front(f, args...)` is a function object that
+   * stores `f` and the bound arguments, `args...`. When that function
+   * object is invoked with `call_args...` it returns the result of calling
+   * `f(args..., call_args...)`.
+   *
+   *  @since C++20
+   */
+  template<typename _Fn, typename... _Args>
+    constexpr _Bind_front_t<_Fn, _Args...>
+    bind_front(_Fn&& __fn, _Args&&... __args)
+    noexcept(is_nothrow_constructible_v<_Bind_front_t<_Fn, _Args...>,
+					int, _Fn, _Args...>)
+    {
+      return _Bind_front_t<_Fn, _Args...>(0, std::forward<_Fn>(__fn),
+					  std::forward<_Args>(__args)...);
+    }
+#endif // C++20
+
+#if __cplusplus >= 201402L
+  /// Generalized negator.
+  template<typename _Fn>
+    class _Not_fn
+    {
+      template<typename _Fn2, typename... _Args>
+	using __inv_res_t = typename __invoke_result<_Fn2, _Args...>::type;
+
+      template<typename _Tp>
+	static decltype(!std::declval<_Tp>())
+	_S_not() noexcept(noexcept(!std::declval<_Tp>()));
+
+    public:
+      template<typename _Fn2>
+	constexpr
+	_Not_fn(_Fn2&& __fn, int)
+	: _M_fn(std::forward<_Fn2>(__fn)) { }
+
+      _Not_fn(const _Not_fn& __fn) = default;
+      _Not_fn(_Not_fn&& __fn) = default;
+      ~_Not_fn() = default;
+
+      // Macro to define operator() with given cv-qualifiers ref-qualifiers,
+      // forwarding _M_fn and the function arguments with the same qualifiers,
+      // and deducing the return type and exception-specification.
+#define _GLIBCXX_NOT_FN_CALL_OP( _QUALS )				\
+      template<typename... _Args>					\
+	_GLIBCXX20_CONSTEXPR						\
+	decltype(_S_not<__inv_res_t<_Fn _QUALS, _Args...>>())		\
+	operator()(_Args&&... __args) _QUALS				\
+	noexcept(__is_nothrow_invocable<_Fn _QUALS, _Args...>::value	\
+	    && noexcept(_S_not<__inv_res_t<_Fn _QUALS, _Args...>>()))	\
+	{								\
+	  return !std::__invoke(std::forward< _Fn _QUALS >(_M_fn),	\
+				std::forward<_Args>(__args)...);	\
+	}
+      _GLIBCXX_NOT_FN_CALL_OP( & )
+      _GLIBCXX_NOT_FN_CALL_OP( const & )
+      _GLIBCXX_NOT_FN_CALL_OP( && )
+      _GLIBCXX_NOT_FN_CALL_OP( const && )
+#undef _GLIBCXX_NOT_FN_CALL_OP
+
+    private:
+      _Fn _M_fn;
+    };
+
+  template<typename _Tp, typename _Pred>
+    struct __is_byte_like : false_type { };
+
+  template<typename _Tp>
+    struct __is_byte_like<_Tp, equal_to<_Tp>>
+    : __bool_constant<sizeof(_Tp) == 1 && is_integral<_Tp>::value> { };
+
+  template<typename _Tp>
+    struct __is_byte_like<_Tp, equal_to<void>>
+    : __bool_constant<sizeof(_Tp) == 1 && is_integral<_Tp>::value> { };
+
+#if __cplusplus >= 201703L
+  // Declare std::byte (full definition is in <cstddef>).
+  enum class byte : unsigned char;
+
+  template<>
+    struct __is_byte_like<byte, equal_to<byte>>
+    : true_type { };
+
+  template<>
+    struct __is_byte_like<byte, equal_to<void>>
+    : true_type { };
+
+  // [func.not_fn] Function template not_fn
+#define __cpp_lib_not_fn 201603L
+  /** Wrap a function object to create one that negates its result.
+   *
+   * The function template `std::not_fn` creates a "forwarding call wrapper",
+   * which is a function object that wraps another function object and
+   * when called, forwards its arguments to the wrapped function object.
+   *
+   * The result of invoking the wrapper is the negation (using `!`) of
+   * the wrapped function object.
+   *
+   *  @ingroup functors
+   *  @since C++17
+   */
+  template<typename _Fn>
+    _GLIBCXX20_CONSTEXPR
+    inline auto
+    not_fn(_Fn&& __fn)
+    noexcept(std::is_nothrow_constructible<std::decay_t<_Fn>, _Fn&&>::value)
+    {
+      return _Not_fn<std::decay_t<_Fn>>{std::forward<_Fn>(__fn), 0};
+    }
+
+  // Searchers
+#define __cpp_lib_boyer_moore_searcher 201603L
+
+  template<typename _ForwardIterator1, typename _BinaryPredicate = equal_to<>>
+    class default_searcher
+    {
+    public:
+      _GLIBCXX20_CONSTEXPR
+      default_searcher(_ForwardIterator1 __pat_first,
+		       _ForwardIterator1 __pat_last,
+		       _BinaryPredicate __pred = _BinaryPredicate())
+      : _M_m(__pat_first, __pat_last, std::move(__pred))
+      { }
+
+      template<typename _ForwardIterator2>
+	_GLIBCXX20_CONSTEXPR
+	pair<_ForwardIterator2, _ForwardIterator2>
+	operator()(_ForwardIterator2 __first, _ForwardIterator2 __last) const
+	{
+	  _ForwardIterator2 __first_ret =
+	    std::search(__first, __last, std::get<0>(_M_m), std::get<1>(_M_m),
+			std::get<2>(_M_m));
+	  auto __ret = std::make_pair(__first_ret, __first_ret);
+	  if (__ret.first != __last)
+	    std::advance(__ret.second, std::distance(std::get<0>(_M_m),
+						     std::get<1>(_M_m)));
+	  return __ret;
+	}
+
+    private:
+      tuple<_ForwardIterator1, _ForwardIterator1, _BinaryPredicate> _M_m;
+    };
+
+  template<typename _Key, typename _Tp, typename _Hash, typename _Pred>
+    struct __boyer_moore_map_base
+    {
+      template<typename _RAIter>
+	__boyer_moore_map_base(_RAIter __pat, size_t __patlen,
+			       _Hash&& __hf, _Pred&& __pred)
+	: _M_bad_char{ __patlen, std::move(__hf), std::move(__pred) }
+	{
+	  if (__patlen > 0)
+	    for (__diff_type __i = 0; __i < __patlen - 1; ++__i)
+	      _M_bad_char[__pat[__i]] = __patlen - 1 - __i;
+	}
+
+      using __diff_type = _Tp;
+
+      __diff_type
+      _M_lookup(_Key __key, __diff_type __not_found) const
+      {
+	auto __iter = _M_bad_char.find(__key);
+	if (__iter == _M_bad_char.end())
+	  return __not_found;
+	return __iter->second;
+      }
+
+      _Pred
+      _M_pred() const { return _M_bad_char.key_eq(); }
+
+      _GLIBCXX_STD_C::unordered_map<_Key, _Tp, _Hash, _Pred> _M_bad_char;
+    };
+
+  template<typename _Tp, size_t _Len, typename _Pred>
+    struct __boyer_moore_array_base
+    {
+      template<typename _RAIter, typename _Unused>
+	__boyer_moore_array_base(_RAIter __pat, size_t __patlen,
+				 _Unused&&, _Pred&& __pred)
+	: _M_bad_char{ array<_Tp, _Len>{}, std::move(__pred) }
+	{
+	  std::get<0>(_M_bad_char).fill(__patlen);
+	  if (__patlen > 0)
+	    for (__diff_type __i = 0; __i < __patlen - 1; ++__i)
+	      {
+		auto __ch = __pat[__i];
+		using _UCh = make_unsigned_t<decltype(__ch)>;
+		auto __uch = static_cast<_UCh>(__ch);
+		std::get<0>(_M_bad_char)[__uch] = __patlen - 1 - __i;
+	      }
+	}
+
+      using __diff_type = _Tp;
+
+      template<typename _Key>
+	__diff_type
+	_M_lookup(_Key __key, __diff_type __not_found) const
+	{
+	  auto __ukey = static_cast<make_unsigned_t<_Key>>(__key);
+	  if (__ukey >= _Len)
+	    return __not_found;
+	  return std::get<0>(_M_bad_char)[__ukey];
+	}
+
+      const _Pred&
+      _M_pred() const { return std::get<1>(_M_bad_char); }
+
+      tuple<array<_Tp, _Len>, _Pred> _M_bad_char;
+    };
+
+  // Use __boyer_moore_array_base when pattern consists of narrow characters
+  // (or std::byte) and uses std::equal_to as the predicate.
+  template<typename _RAIter, typename _Hash, typename _Pred,
+           typename _Val = typename iterator_traits<_RAIter>::value_type,
+	   typename _Diff = typename iterator_traits<_RAIter>::difference_type>
+    using __boyer_moore_base_t
+      = __conditional_t<__is_byte_like<_Val, _Pred>::value,
+			__boyer_moore_array_base<_Diff, 256, _Pred>,
+			__boyer_moore_map_base<_Val, _Diff, _Hash, _Pred>>;
+
+  template<typename _RAIter, typename _Hash
+	     = hash<typename iterator_traits<_RAIter>::value_type>,
+	   typename _BinaryPredicate = equal_to<>>
+    class boyer_moore_searcher
+    : __boyer_moore_base_t<_RAIter, _Hash, _BinaryPredicate>
+    {
+      using _Base = __boyer_moore_base_t<_RAIter, _Hash, _BinaryPredicate>;
+      using typename _Base::__diff_type;
+
+    public:
+      boyer_moore_searcher(_RAIter __pat_first, _RAIter __pat_last,
+			   _Hash __hf = _Hash(),
+			   _BinaryPredicate __pred = _BinaryPredicate());
+
+      template<typename _RandomAccessIterator2>
+        pair<_RandomAccessIterator2, _RandomAccessIterator2>
+	operator()(_RandomAccessIterator2 __first,
+		   _RandomAccessIterator2 __last) const;
+
+    private:
+      bool
+      _M_is_prefix(_RAIter __word, __diff_type __len,
+		   __diff_type __pos)
+      {
+	const auto& __pred = this->_M_pred();
+	__diff_type __suffixlen = __len - __pos;
+	for (__diff_type __i = 0; __i < __suffixlen; ++__i)
+	  if (!__pred(__word[__i], __word[__pos + __i]))
+	    return false;
+	return true;
+      }
+
+      __diff_type
+      _M_suffix_length(_RAIter __word, __diff_type __len,
+		       __diff_type __pos)
+      {
+	const auto& __pred = this->_M_pred();
+	__diff_type __i = 0;
+	while (__pred(__word[__pos - __i], __word[__len - 1 - __i])
+	       && __i < __pos)
+	  {
+	    ++__i;
+	  }
+	return __i;
+      }
+
+      template<typename _Tp>
+	__diff_type
+	_M_bad_char_shift(_Tp __c) const
+	{ return this->_M_lookup(__c, _M_pat_end - _M_pat); }
+
+      _RAIter _M_pat;
+      _RAIter _M_pat_end;
+      _GLIBCXX_STD_C::vector<__diff_type> _M_good_suffix;
+    };
+
+  template<typename _RAIter, typename _Hash
+	     = hash<typename iterator_traits<_RAIter>::value_type>,
+	   typename _BinaryPredicate = equal_to<>>
+    class boyer_moore_horspool_searcher
+    : __boyer_moore_base_t<_RAIter, _Hash, _BinaryPredicate>
+    {
+      using _Base = __boyer_moore_base_t<_RAIter, _Hash, _BinaryPredicate>;
+      using typename _Base::__diff_type;
+
+    public:
+      boyer_moore_horspool_searcher(_RAIter __pat,
+				    _RAIter __pat_end,
+				    _Hash __hf = _Hash(),
+				    _BinaryPredicate __pred
+				    = _BinaryPredicate())
+      : _Base(__pat, __pat_end - __pat, std::move(__hf), std::move(__pred)),
+	_M_pat(__pat), _M_pat_end(__pat_end)
+      { }
+
+      template<typename _RandomAccessIterator2>
+        pair<_RandomAccessIterator2, _RandomAccessIterator2>
+	operator()(_RandomAccessIterator2 __first,
+		   _RandomAccessIterator2 __last) const
+	{
+	  const auto& __pred = this->_M_pred();
+	  auto __patlen = _M_pat_end - _M_pat;
+	  if (__patlen == 0)
+	    return std::make_pair(__first, __first);
+	  auto __len = __last - __first;
+	  while (__len >= __patlen)
+	    {
+	      for (auto __scan = __patlen - 1;
+		   __pred(__first[__scan], _M_pat[__scan]); --__scan)
+		if (__scan == 0)
+		  return std::make_pair(__first, __first + __patlen);
+	      auto __shift = _M_bad_char_shift(__first[__patlen - 1]);
+	      __len -= __shift;
+	      __first += __shift;
+	    }
+	  return std::make_pair(__last, __last);
+	}
+
+    private:
+      template<typename _Tp>
+	__diff_type
+	_M_bad_char_shift(_Tp __c) const
+	{ return this->_M_lookup(__c, _M_pat_end - _M_pat); }
+
+      _RAIter _M_pat;
+      _RAIter _M_pat_end;
+    };
+
+  template<typename _RAIter, typename _Hash, typename _BinaryPredicate>
+    boyer_moore_searcher<_RAIter, _Hash, _BinaryPredicate>::
+    boyer_moore_searcher(_RAIter __pat, _RAIter __pat_end,
+			 _Hash __hf, _BinaryPredicate __pred)
+    : _Base(__pat, __pat_end - __pat, std::move(__hf), std::move(__pred)),
+      _M_pat(__pat), _M_pat_end(__pat_end), _M_good_suffix(__pat_end - __pat)
+    {
+      auto __patlen = __pat_end - __pat;
+      if (__patlen == 0)
+	return;
+      __diff_type __last_prefix = __patlen - 1;
+      for (__diff_type __p = __patlen - 1; __p >= 0; --__p)
+	{
+	  if (_M_is_prefix(__pat, __patlen, __p + 1))
+	    __last_prefix = __p + 1;
+	  _M_good_suffix[__p] = __last_prefix + (__patlen - 1 - __p);
+	}
+      for (__diff_type __p = 0; __p < __patlen - 1; ++__p)
+	{
+	  auto __slen = _M_suffix_length(__pat, __patlen, __p);
+	  auto __pos = __patlen - 1 - __slen;
+	  if (!__pred(__pat[__p - __slen], __pat[__pos]))
+	    _M_good_suffix[__pos] = __patlen - 1 - __p + __slen;
+	}
+    }
+
+  template<typename _RAIter, typename _Hash, typename _BinaryPredicate>
+  template<typename _RandomAccessIterator2>
+    pair<_RandomAccessIterator2, _RandomAccessIterator2>
+    boyer_moore_searcher<_RAIter, _Hash, _BinaryPredicate>::
+    operator()(_RandomAccessIterator2 __first,
+	       _RandomAccessIterator2 __last) const
+    {
+      auto __patlen = _M_pat_end - _M_pat;
+      if (__patlen == 0)
+	return std::make_pair(__first, __first);
+      const auto& __pred = this->_M_pred();
+      __diff_type __i = __patlen - 1;
+      auto __stringlen = __last - __first;
+      while (__i < __stringlen)
+	{
+	  __diff_type __j = __patlen - 1;
+	  while (__j >= 0 && __pred(__first[__i], _M_pat[__j]))
+	    {
+	      --__i;
+	      --__j;
+	    }
+	  if (__j < 0)
+	    {
+	      const auto __match = __first + __i + 1;
+	      return std::make_pair(__match, __match + __patlen);
+	    }
+	  __i += std::max(_M_bad_char_shift(__first[__i]),
+			  _M_good_suffix[__j]);
+	}
+      return std::make_pair(__last, __last);
+    }
+
+#endif // C++17
+#endif // C++14
+#endif // C++11
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif // _GLIBCXX_FUNCTIONAL
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@@ -0,0 +1,1819 @@
+// <future> -*- C++ -*-
+
+// Copyright (C) 2009-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file include/future
+ *  This is a Standard C++ Library header.
+ */
+
+#ifndef _GLIBCXX_FUTURE
+#define _GLIBCXX_FUTURE 1
+
+#pragma GCC system_header
+
+#if __cplusplus < 201103L
+# include <bits/c++0x_warning.h>
+#else
+
+#include <mutex>	      // call_once
+#include <condition_variable> // __at_thread_exit_elt
+#include <system_error>
+#include <bits/atomic_base.h> // atomic_flag
+#include <bits/allocated_ptr.h>
+#include <bits/atomic_futex.h>
+#include <bits/exception_defines.h>
+#include <bits/invoke.h>
+#include <bits/unique_ptr.h>
+#include <bits/shared_ptr.h>
+#include <bits/std_function.h>
+#include <bits/std_thread.h>
+#include <bits/uses_allocator.h>
+#include <ext/aligned_buffer.h>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /**
+   * @defgroup futures Futures
+   * @ingroup concurrency
+   *
+   * Classes for futures support.
+   * @{
+   */
+
+  /// Error code for futures
+  enum class future_errc
+  {
+    future_already_retrieved = 1,
+    promise_already_satisfied,
+    no_state,
+    broken_promise
+  };
+
+  /// Specialization.
+  template<>
+    struct is_error_code_enum<future_errc> : public true_type { };
+
+  /// Points to a statically-allocated object derived from error_category.
+  const error_category&
+  future_category() noexcept;
+
+  /// Overload for make_error_code.
+  inline error_code
+  make_error_code(future_errc __errc) noexcept
+  { return error_code(static_cast<int>(__errc), future_category()); }
+
+  /// Overload for make_error_condition.
+  inline error_condition
+  make_error_condition(future_errc __errc) noexcept
+  { return error_condition(static_cast<int>(__errc), future_category()); }
+
+  /**
+   *  @brief Exception type thrown by futures.
+   *  @ingroup exceptions
+   */
+  class future_error : public logic_error
+  {
+  public:
+    explicit
+    future_error(future_errc __errc)
+    : future_error(std::make_error_code(__errc))
+    { }
+
+    virtual ~future_error() noexcept;
+
+    virtual const char*
+    what() const noexcept;
+
+    const error_code&
+    code() const noexcept { return _M_code; }
+
+  private:
+    explicit
+    future_error(error_code __ec)
+    : logic_error("std::future_error: " + __ec.message()), _M_code(__ec)
+    { }
+
+    friend void __throw_future_error(int);
+
+    error_code 			_M_code;
+  };
+
+  // Forward declarations.
+  template<typename _Res>
+    class future;
+
+  template<typename _Res>
+    class shared_future;
+
+  template<typename _Signature>
+    class packaged_task;
+
+  template<typename _Res>
+    class promise;
+
+  /// Launch code for futures
+  enum class launch
+  {
+    async = 1,
+    deferred = 2
+  };
+
+  constexpr launch operator&(launch __x, launch __y) noexcept
+  {
+    return static_cast<launch>(
+	static_cast<int>(__x) & static_cast<int>(__y));
+  }
+
+  constexpr launch operator|(launch __x, launch __y) noexcept
+  {
+    return static_cast<launch>(
+	static_cast<int>(__x) | static_cast<int>(__y));
+  }
+
+  constexpr launch operator^(launch __x, launch __y) noexcept
+  {
+    return static_cast<launch>(
+	static_cast<int>(__x) ^ static_cast<int>(__y));
+  }
+
+  constexpr launch operator~(launch __x) noexcept
+  { return static_cast<launch>(~static_cast<int>(__x)); }
+
+  inline launch& operator&=(launch& __x, launch __y) noexcept
+  { return __x = __x & __y; }
+
+  inline launch& operator|=(launch& __x, launch __y) noexcept
+  { return __x = __x | __y; }
+
+  inline launch& operator^=(launch& __x, launch __y) noexcept
+  { return __x = __x ^ __y; }
+
+  /// Status code for futures
+  enum class future_status
+  {
+    ready,
+    timeout,
+    deferred
+  };
+
+  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+  // 2021. Further incorrect usages of result_of
+  template<typename _Fn, typename... _Args>
+    using __async_result_of = typename __invoke_result<
+      typename decay<_Fn>::type, typename decay<_Args>::type...>::type;
+
+  template<typename _Fn, typename... _Args>
+    future<__async_result_of<_Fn, _Args...>>
+    async(launch __policy, _Fn&& __fn, _Args&&... __args);
+
+  template<typename _Fn, typename... _Args>
+    future<__async_result_of<_Fn, _Args...>>
+    async(_Fn&& __fn, _Args&&... __args);
+
+#if defined(_GLIBCXX_HAS_GTHREADS)
+
+  /// Base class and enclosing scope.
+  struct __future_base
+  {
+    /// Base class for results.
+    struct _Result_base
+    {
+      exception_ptr		_M_error;
+
+      _Result_base(const _Result_base&) = delete;
+      _Result_base& operator=(const _Result_base&) = delete;
+
+      // _M_destroy() allows derived classes to control deallocation
+      virtual void _M_destroy() = 0;
+
+      struct _Deleter
+      {
+	void operator()(_Result_base* __fr) const { __fr->_M_destroy(); }
+      };
+
+    protected:
+      _Result_base();
+      virtual ~_Result_base();
+    };
+
+    /// A unique_ptr for result objects.
+    template<typename _Res>
+      using _Ptr = unique_ptr<_Res, _Result_base::_Deleter>;
+
+    /// A result object that has storage for an object of type _Res.
+    template<typename _Res>
+      struct _Result : _Result_base
+      {
+      private:
+	__gnu_cxx::__aligned_buffer<_Res>	_M_storage;
+	bool 					_M_initialized;
+
+      public:
+	typedef _Res result_type;
+
+	_Result() noexcept : _M_initialized() { }
+
+	~_Result()
+	{
+	  if (_M_initialized)
+	    _M_value().~_Res();
+	}
+
+	// Return lvalue, future will add const or rvalue-reference
+	_Res&
+	_M_value() noexcept { return *_M_storage._M_ptr(); }
+
+	void
+	_M_set(const _Res& __res)
+	{
+	  ::new (_M_storage._M_addr()) _Res(__res);
+	  _M_initialized = true;
+	}
+
+	void
+	_M_set(_Res&& __res)
+	{
+	  ::new (_M_storage._M_addr()) _Res(std::move(__res));
+	  _M_initialized = true;
+	}
+
+      private:
+	void _M_destroy() { delete this; }
+    };
+
+    /// A result object that uses an allocator.
+    template<typename _Res, typename _Alloc>
+      struct _Result_alloc final : _Result<_Res>, _Alloc
+      {
+	using __allocator_type = __alloc_rebind<_Alloc, _Result_alloc>;
+
+        explicit
+	_Result_alloc(const _Alloc& __a) : _Result<_Res>(), _Alloc(__a)
+	{ }
+
+      private:
+	void _M_destroy()
+	{
+	  __allocator_type __a(*this);
+	  __allocated_ptr<__allocator_type> __guard_ptr{ __a, this };
+	  this->~_Result_alloc();
+	}
+      };
+
+    // Create a result object that uses an allocator.
+    template<typename _Res, typename _Allocator>
+      static _Ptr<_Result_alloc<_Res, _Allocator>>
+      _S_allocate_result(const _Allocator& __a)
+      {
+	using __result_type = _Result_alloc<_Res, _Allocator>;
+	typename __result_type::__allocator_type __a2(__a);
+	auto __guard = std::__allocate_guarded(__a2);
+	__result_type* __p = ::new((void*)__guard.get()) __result_type{__a};
+	__guard = nullptr;
+	return _Ptr<__result_type>(__p);
+      }
+
+    // Keep it simple for std::allocator.
+    template<typename _Res, typename _Tp>
+      static _Ptr<_Result<_Res>>
+      _S_allocate_result(const std::allocator<_Tp>& __a)
+      {
+	return _Ptr<_Result<_Res>>(new _Result<_Res>);
+      }
+
+    // Base class for various types of shared state created by an
+    // asynchronous provider (such as a std::promise) and shared with one
+    // or more associated futures.
+    class _State_baseV2
+    {
+      typedef _Ptr<_Result_base> _Ptr_type;
+
+      enum _Status : unsigned {
+	__not_ready,
+	__ready
+      };
+
+      _Ptr_type			_M_result;
+      __atomic_futex_unsigned<>	_M_status;
+      atomic_flag         	_M_retrieved = ATOMIC_FLAG_INIT;
+      once_flag			_M_once;
+
+    public:
+      _State_baseV2() noexcept : _M_result(), _M_status(_Status::__not_ready)
+	{ }
+      _State_baseV2(const _State_baseV2&) = delete;
+      _State_baseV2& operator=(const _State_baseV2&) = delete;
+      virtual ~_State_baseV2() = default;
+
+      _Result_base&
+      wait()
+      {
+	// Run any deferred function or join any asynchronous thread:
+	_M_complete_async();
+	// Acquire MO makes sure this synchronizes with the thread that made
+	// the future ready.
+	_M_status._M_load_when_equal(_Status::__ready, memory_order_acquire);
+	return *_M_result;
+      }
+
+      template<typename _Rep, typename _Period>
+        future_status
+        wait_for(const chrono::duration<_Rep, _Period>& __rel)
+        {
+	  // First, check if the future has been made ready.  Use acquire MO
+	  // to synchronize with the thread that made it ready.
+	  if (_M_status._M_load(memory_order_acquire) == _Status::__ready)
+	    return future_status::ready;
+
+	  if (_M_is_deferred_future())
+	    return future_status::deferred;
+
+	  // Don't wait unless the relative time is greater than zero.
+	  if (__rel > __rel.zero()
+	      && _M_status._M_load_when_equal_for(_Status::__ready,
+						  memory_order_acquire,
+						  __rel))
+	    {
+	      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+	      // 2100.  timed waiting functions must also join
+	      // This call is a no-op by default except on an async future,
+	      // in which case the async thread is joined.  It's also not a
+	      // no-op for a deferred future, but such a future will never
+	      // reach this point because it returns future_status::deferred
+	      // instead of waiting for the future to become ready (see
+	      // above).  Async futures synchronize in this call, so we need
+	      // no further synchronization here.
+	      _M_complete_async();
+
+	      return future_status::ready;
+	    }
+	  return future_status::timeout;
+	}
+
+      template<typename _Clock, typename _Duration>
+        future_status
+        wait_until(const chrono::time_point<_Clock, _Duration>& __abs)
+        {
+#if __cplusplus > 201703L
+	  static_assert(chrono::is_clock_v<_Clock>);
+#endif
+	  // First, check if the future has been made ready.  Use acquire MO
+	  // to synchronize with the thread that made it ready.
+	  if (_M_status._M_load(memory_order_acquire) == _Status::__ready)
+	    return future_status::ready;
+
+	  if (_M_is_deferred_future())
+	    return future_status::deferred;
+
+	  if (_M_status._M_load_when_equal_until(_Status::__ready,
+						 memory_order_acquire,
+						 __abs))
+	    {
+	      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+	      // 2100.  timed waiting functions must also join
+	      // See wait_for(...) above.
+	      _M_complete_async();
+
+	      return future_status::ready;
+	    }
+	  return future_status::timeout;
+	}
+
+      // Provide a result to the shared state and make it ready.
+      // Calls at most once: _M_result = __res();
+      void
+      _M_set_result(function<_Ptr_type()> __res, bool __ignore_failure = false)
+      {
+	bool __did_set = false;
+        // all calls to this function are serialized,
+        // side-effects of invoking __res only happen once
+	call_once(_M_once, &_State_baseV2::_M_do_set, this,
+		  std::__addressof(__res), std::__addressof(__did_set));
+	if (__did_set)
+	  // Use release MO to synchronize with observers of the ready state.
+	  _M_status._M_store_notify_all(_Status::__ready,
+					memory_order_release);
+	else if (!__ignore_failure)
+          __throw_future_error(int(future_errc::promise_already_satisfied));
+      }
+
+      // Provide a result to the shared state but delay making it ready
+      // until the calling thread exits.
+      // Calls at most once: _M_result = __res();
+      void
+      _M_set_delayed_result(function<_Ptr_type()> __res,
+			    weak_ptr<_State_baseV2> __self)
+      {
+	bool __did_set = false;
+	unique_ptr<_Make_ready> __mr{new _Make_ready};
+        // all calls to this function are serialized,
+        // side-effects of invoking __res only happen once
+	call_once(_M_once, &_State_baseV2::_M_do_set, this,
+		  std::__addressof(__res), std::__addressof(__did_set));
+	if (!__did_set)
+          __throw_future_error(int(future_errc::promise_already_satisfied));
+	__mr->_M_shared_state = std::move(__self);
+	__mr->_M_set();
+	__mr.release();
+      }
+
+      // Abandon this shared state.
+      void
+      _M_break_promise(_Ptr_type __res)
+      {
+	if (static_cast<bool>(__res))
+	  {
+	    __res->_M_error =
+	      make_exception_ptr(future_error(future_errc::broken_promise));
+	    // This function is only called when the last asynchronous result
+	    // provider is abandoning this shared state, so noone can be
+	    // trying to make the shared state ready at the same time, and
+	    // we can access _M_result directly instead of through call_once.
+	    _M_result.swap(__res);
+	    // Use release MO to synchronize with observers of the ready state.
+	    _M_status._M_store_notify_all(_Status::__ready,
+					  memory_order_release);
+	  }
+      }
+
+      // Called when this object is first passed to a future.
+      void
+      _M_set_retrieved_flag()
+      {
+	if (_M_retrieved.test_and_set())
+	  __throw_future_error(int(future_errc::future_already_retrieved));
+      }
+
+      template<typename _Res, typename _Arg>
+        struct _Setter;
+
+      // set lvalues
+      template<typename _Res, typename _Arg>
+        struct _Setter<_Res, _Arg&>
+        {
+          // check this is only used by promise<R>::set_value(const R&)
+          // or promise<R&>::set_value(R&)
+          static_assert(is_same<_Res, _Arg&>::value  // promise<R&>
+              || is_same<const _Res, _Arg>::value,   // promise<R>
+              "Invalid specialisation");
+
+	  // Used by std::promise to copy construct the result.
+          typename promise<_Res>::_Ptr_type operator()() const
+          {
+            _M_promise->_M_storage->_M_set(*_M_arg);
+            return std::move(_M_promise->_M_storage);
+          }
+          promise<_Res>*    _M_promise;
+          _Arg*             _M_arg;
+        };
+
+      // set rvalues
+      template<typename _Res>
+        struct _Setter<_Res, _Res&&>
+        {
+	  // Used by std::promise to move construct the result.
+          typename promise<_Res>::_Ptr_type operator()() const
+          {
+            _M_promise->_M_storage->_M_set(std::move(*_M_arg));
+            return std::move(_M_promise->_M_storage);
+          }
+          promise<_Res>*    _M_promise;
+          _Res*             _M_arg;
+        };
+
+      // set void
+      template<typename _Res>
+	struct _Setter<_Res, void>
+	{
+	  static_assert(is_void<_Res>::value, "Only used for promise<void>");
+
+	  typename promise<_Res>::_Ptr_type operator()() const
+	  { return std::move(_M_promise->_M_storage); }
+
+	  promise<_Res>*    _M_promise;
+	};
+
+      struct __exception_ptr_tag { };
+
+      // set exceptions
+      template<typename _Res>
+        struct _Setter<_Res, __exception_ptr_tag>
+        {
+	  // Used by std::promise to store an exception as the result.
+          typename promise<_Res>::_Ptr_type operator()() const
+          {
+            _M_promise->_M_storage->_M_error = *_M_ex;
+            return std::move(_M_promise->_M_storage);
+          }
+
+          promise<_Res>*   _M_promise;
+          exception_ptr*    _M_ex;
+        };
+
+      template<typename _Res, typename _Arg>
+	__attribute__((__always_inline__))
+        static _Setter<_Res, _Arg&&>
+        __setter(promise<_Res>* __prom, _Arg&& __arg) noexcept
+        {
+          return _Setter<_Res, _Arg&&>{ __prom, std::__addressof(__arg) };
+        }
+
+      template<typename _Res>
+	__attribute__((__always_inline__))
+        static _Setter<_Res, __exception_ptr_tag>
+        __setter(exception_ptr& __ex, promise<_Res>* __prom) noexcept
+        {
+          return _Setter<_Res, __exception_ptr_tag>{ __prom, &__ex };
+        }
+
+      template<typename _Res>
+	__attribute__((__always_inline__))
+	static _Setter<_Res, void>
+	__setter(promise<_Res>* __prom) noexcept
+	{
+	  return _Setter<_Res, void>{ __prom };
+	}
+
+      template<typename _Tp>
+        static void
+        _S_check(const shared_ptr<_Tp>& __p)
+        {
+          if (!static_cast<bool>(__p))
+            __throw_future_error((int)future_errc::no_state);
+        }
+
+    private:
+      // The function invoked with std::call_once(_M_once, ...).
+      void
+      _M_do_set(function<_Ptr_type()>* __f, bool* __did_set)
+      {
+        _Ptr_type __res = (*__f)();
+        // Notify the caller that we did try to set; if we do not throw an
+        // exception, the caller will be aware that it did set (e.g., see
+        // _M_set_result).
+	*__did_set = true;
+        _M_result.swap(__res); // nothrow
+      }
+
+      // Wait for completion of async function.
+      virtual void _M_complete_async() { }
+
+      // Return true if state corresponds to a deferred function.
+      virtual bool _M_is_deferred_future() const { return false; }
+
+      struct _Make_ready final : __at_thread_exit_elt
+      {
+	weak_ptr<_State_baseV2> _M_shared_state;
+	static void _S_run(void*);
+	void _M_set();
+      };
+    };
+
+#ifdef _GLIBCXX_ASYNC_ABI_COMPAT
+    class _State_base;
+    class _Async_state_common;
+#else
+    using _State_base = _State_baseV2;
+    class _Async_state_commonV2;
+#endif
+
+    template<typename _BoundFn,
+	     typename _Res = decltype(std::declval<_BoundFn&>()())>
+      class _Deferred_state;
+
+    template<typename _BoundFn,
+	     typename _Res = decltype(std::declval<_BoundFn&>()())>
+      class _Async_state_impl;
+
+    template<typename _Signature>
+      class _Task_state_base;
+
+    template<typename _Fn, typename _Alloc, typename _Signature>
+      class _Task_state;
+
+    template<typename _Res_ptr, typename _Fn,
+	     typename _Res = typename _Res_ptr::element_type::result_type>
+      struct _Task_setter;
+
+    template<typename _Res_ptr, typename _BoundFn>
+      static _Task_setter<_Res_ptr, _BoundFn>
+      _S_task_setter(_Res_ptr& __ptr, _BoundFn& __call)
+      {
+	return { std::__addressof(__ptr), std::__addressof(__call) };
+      }
+  };
+
+  /// Partial specialization for reference types.
+  template<typename _Res>
+    struct __future_base::_Result<_Res&> : __future_base::_Result_base
+    {
+      typedef _Res& result_type;
+
+      _Result() noexcept : _M_value_ptr() { }
+
+      void
+      _M_set(_Res& __res) noexcept
+      { _M_value_ptr = std::addressof(__res); }
+
+      _Res& _M_get() noexcept { return *_M_value_ptr; }
+
+    private:
+      _Res* 			_M_value_ptr;
+
+      void _M_destroy() { delete this; }
+    };
+
+  /// Explicit specialization for void.
+  template<>
+    struct __future_base::_Result<void> : __future_base::_Result_base
+    {
+      typedef void result_type;
+
+    private:
+      void _M_destroy() { delete this; }
+    };
+
+#ifndef _GLIBCXX_ASYNC_ABI_COMPAT
+
+  // Allow _Setter objects to be stored locally in std::function
+  template<typename _Res, typename _Arg>
+    struct __is_location_invariant
+    <__future_base::_State_base::_Setter<_Res, _Arg>>
+    : true_type { };
+
+  // Allow _Task_setter objects to be stored locally in std::function
+  template<typename _Res_ptr, typename _Fn, typename _Res>
+    struct __is_location_invariant
+    <__future_base::_Task_setter<_Res_ptr, _Fn, _Res>>
+    : true_type { };
+
+  /// Common implementation for future and shared_future.
+  template<typename _Res>
+    class __basic_future : public __future_base
+    {
+    protected:
+      typedef shared_ptr<_State_base>		__state_type;
+      typedef __future_base::_Result<_Res>&	__result_type;
+
+    private:
+      __state_type 		_M_state;
+
+    public:
+      // Disable copying.
+      __basic_future(const __basic_future&) = delete;
+      __basic_future& operator=(const __basic_future&) = delete;
+
+      bool
+      valid() const noexcept { return static_cast<bool>(_M_state); }
+
+      void
+      wait() const
+      {
+        _State_base::_S_check(_M_state);
+        _M_state->wait();
+      }
+
+      template<typename _Rep, typename _Period>
+        future_status
+        wait_for(const chrono::duration<_Rep, _Period>& __rel) const
+        {
+          _State_base::_S_check(_M_state);
+          return _M_state->wait_for(__rel);
+        }
+
+      template<typename _Clock, typename _Duration>
+        future_status
+        wait_until(const chrono::time_point<_Clock, _Duration>& __abs) const
+        {
+          _State_base::_S_check(_M_state);
+          return _M_state->wait_until(__abs);
+        }
+
+    protected:
+      /// Wait for the state to be ready and rethrow any stored exception
+      __result_type
+      _M_get_result() const
+      {
+        _State_base::_S_check(_M_state);
+        _Result_base& __res = _M_state->wait();
+        if (!(__res._M_error == nullptr))
+          rethrow_exception(__res._M_error);
+        return static_cast<__result_type>(__res);
+      }
+
+      void _M_swap(__basic_future& __that) noexcept
+      {
+        _M_state.swap(__that._M_state);
+      }
+
+      // Construction of a future by promise::get_future()
+      explicit
+      __basic_future(const __state_type& __state) : _M_state(__state)
+      {
+        _State_base::_S_check(_M_state);
+        _M_state->_M_set_retrieved_flag();
+      }
+
+      // Copy construction from a shared_future
+      explicit
+      __basic_future(const shared_future<_Res>&) noexcept;
+
+      // Move construction from a shared_future
+      explicit
+      __basic_future(shared_future<_Res>&&) noexcept;
+
+      // Move construction from a future
+      explicit
+      __basic_future(future<_Res>&&) noexcept;
+
+      constexpr __basic_future() noexcept : _M_state() { }
+
+      struct _Reset
+      {
+        explicit _Reset(__basic_future& __fut) noexcept : _M_fut(__fut) { }
+        ~_Reset() { _M_fut._M_state.reset(); }
+        __basic_future& _M_fut;
+      };
+    };
+
+
+  /// Primary template for future.
+  template<typename _Res>
+    class future : public __basic_future<_Res>
+    {
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 3458. Is shared_future intended to work with arrays or function types?
+      static_assert(!is_array<_Res>{}, "result type must not be an array");
+      static_assert(!is_function<_Res>{}, "result type must not be a function");
+      static_assert(is_destructible<_Res>{},
+		    "result type must be destructible");
+
+      friend class promise<_Res>;
+      template<typename> friend class packaged_task;
+      template<typename _Fn, typename... _Args>
+        friend future<__async_result_of<_Fn, _Args...>>
+        async(launch, _Fn&&, _Args&&...);
+
+      typedef __basic_future<_Res> _Base_type;
+      typedef typename _Base_type::__state_type __state_type;
+
+      explicit
+      future(const __state_type& __state) : _Base_type(__state) { }
+
+    public:
+      constexpr future() noexcept : _Base_type() { }
+
+      /// Move constructor
+      future(future&& __uf) noexcept : _Base_type(std::move(__uf)) { }
+
+      // Disable copying
+      future(const future&) = delete;
+      future& operator=(const future&) = delete;
+
+      future& operator=(future&& __fut) noexcept
+      {
+        future(std::move(__fut))._M_swap(*this);
+        return *this;
+      }
+
+      /// Retrieving the value
+      _Res
+      get()
+      {
+        typename _Base_type::_Reset __reset(*this);
+        return std::move(this->_M_get_result()._M_value());
+      }
+
+      shared_future<_Res> share() noexcept;
+    };
+
+  /// Partial specialization for future<R&>
+  template<typename _Res>
+    class future<_Res&> : public __basic_future<_Res&>
+    {
+      friend class promise<_Res&>;
+      template<typename> friend class packaged_task;
+      template<typename _Fn, typename... _Args>
+        friend future<__async_result_of<_Fn, _Args...>>
+        async(launch, _Fn&&, _Args&&...);
+
+      typedef __basic_future<_Res&> _Base_type;
+      typedef typename _Base_type::__state_type __state_type;
+
+      explicit
+      future(const __state_type& __state) : _Base_type(__state) { }
+
+    public:
+      constexpr future() noexcept : _Base_type() { }
+
+      /// Move constructor
+      future(future&& __uf) noexcept : _Base_type(std::move(__uf)) { }
+
+      // Disable copying
+      future(const future&) = delete;
+      future& operator=(const future&) = delete;
+
+      future& operator=(future&& __fut) noexcept
+      {
+        future(std::move(__fut))._M_swap(*this);
+        return *this;
+      }
+
+      /// Retrieving the value
+      _Res&
+      get()
+      {
+        typename _Base_type::_Reset __reset(*this);
+        return this->_M_get_result()._M_get();
+      }
+
+      shared_future<_Res&> share() noexcept;
+    };
+
+  /// Explicit specialization for future<void>
+  template<>
+    class future<void> : public __basic_future<void>
+    {
+      friend class promise<void>;
+      template<typename> friend class packaged_task;
+      template<typename _Fn, typename... _Args>
+        friend future<__async_result_of<_Fn, _Args...>>
+        async(launch, _Fn&&, _Args&&...);
+
+      typedef __basic_future<void> _Base_type;
+      typedef typename _Base_type::__state_type __state_type;
+
+      explicit
+      future(const __state_type& __state) : _Base_type(__state) { }
+
+    public:
+      constexpr future() noexcept : _Base_type() { }
+
+      /// Move constructor
+      future(future&& __uf) noexcept : _Base_type(std::move(__uf)) { }
+
+      // Disable copying
+      future(const future&) = delete;
+      future& operator=(const future&) = delete;
+
+      future& operator=(future&& __fut) noexcept
+      {
+        future(std::move(__fut))._M_swap(*this);
+        return *this;
+      }
+
+      /// Retrieving the value
+      void
+      get()
+      {
+        typename _Base_type::_Reset __reset(*this);
+        this->_M_get_result();
+      }
+
+      shared_future<void> share() noexcept;
+    };
+
+
+  /// Primary template for shared_future.
+  template<typename _Res>
+    class shared_future : public __basic_future<_Res>
+    {
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 3458. Is shared_future intended to work with arrays or function types?
+      static_assert(!is_array<_Res>{}, "result type must not be an array");
+      static_assert(!is_function<_Res>{}, "result type must not be a function");
+      static_assert(is_destructible<_Res>{},
+		    "result type must be destructible");
+
+      typedef __basic_future<_Res> _Base_type;
+
+    public:
+      constexpr shared_future() noexcept : _Base_type() { }
+
+      /// Copy constructor
+      shared_future(const shared_future& __sf) noexcept : _Base_type(__sf) { }
+
+      /// Construct from a future rvalue
+      shared_future(future<_Res>&& __uf) noexcept
+      : _Base_type(std::move(__uf))
+      { }
+
+      /// Construct from a shared_future rvalue
+      shared_future(shared_future&& __sf) noexcept
+      : _Base_type(std::move(__sf))
+      { }
+
+      shared_future& operator=(const shared_future& __sf) noexcept
+      {
+        shared_future(__sf)._M_swap(*this);
+        return *this;
+      }
+
+      shared_future& operator=(shared_future&& __sf) noexcept
+      {
+        shared_future(std::move(__sf))._M_swap(*this);
+        return *this;
+      }
+
+      /// Retrieving the value
+      const _Res&
+      get() const { return this->_M_get_result()._M_value(); }
+    };
+
+  /// Partial specialization for shared_future<R&>
+  template<typename _Res>
+    class shared_future<_Res&> : public __basic_future<_Res&>
+    {
+      typedef __basic_future<_Res&>           _Base_type;
+
+    public:
+      constexpr shared_future() noexcept : _Base_type() { }
+
+      /// Copy constructor
+      shared_future(const shared_future& __sf) : _Base_type(__sf) { }
+
+      /// Construct from a future rvalue
+      shared_future(future<_Res&>&& __uf) noexcept
+      : _Base_type(std::move(__uf))
+      { }
+
+      /// Construct from a shared_future rvalue
+      shared_future(shared_future&& __sf) noexcept
+      : _Base_type(std::move(__sf))
+      { }
+
+      shared_future& operator=(const shared_future& __sf)
+      {
+        shared_future(__sf)._M_swap(*this);
+        return *this;
+      }
+
+      shared_future& operator=(shared_future&& __sf) noexcept
+      {
+        shared_future(std::move(__sf))._M_swap(*this);
+        return *this;
+      }
+
+      /// Retrieving the value
+      _Res&
+      get() const { return this->_M_get_result()._M_get(); }
+    };
+
+  /// Explicit specialization for shared_future<void>
+  template<>
+    class shared_future<void> : public __basic_future<void>
+    {
+      typedef __basic_future<void> _Base_type;
+
+    public:
+      constexpr shared_future() noexcept : _Base_type() { }
+
+      /// Copy constructor
+      shared_future(const shared_future& __sf) : _Base_type(__sf) { }
+
+      /// Construct from a future rvalue
+      shared_future(future<void>&& __uf) noexcept
+      : _Base_type(std::move(__uf))
+      { }
+
+      /// Construct from a shared_future rvalue
+      shared_future(shared_future&& __sf) noexcept
+      : _Base_type(std::move(__sf))
+      { }
+
+      shared_future& operator=(const shared_future& __sf)
+      {
+        shared_future(__sf)._M_swap(*this);
+        return *this;
+      }
+
+      shared_future& operator=(shared_future&& __sf) noexcept
+      {
+        shared_future(std::move(__sf))._M_swap(*this);
+        return *this;
+      }
+
+      // Retrieving the value
+      void
+      get() const { this->_M_get_result(); }
+    };
+
+  // Now we can define the protected __basic_future constructors.
+  template<typename _Res>
+    inline __basic_future<_Res>::
+    __basic_future(const shared_future<_Res>& __sf) noexcept
+    : _M_state(__sf._M_state)
+    { }
+
+  template<typename _Res>
+    inline __basic_future<_Res>::
+    __basic_future(shared_future<_Res>&& __sf) noexcept
+    : _M_state(std::move(__sf._M_state))
+    { }
+
+  template<typename _Res>
+    inline __basic_future<_Res>::
+    __basic_future(future<_Res>&& __uf) noexcept
+    : _M_state(std::move(__uf._M_state))
+    { }
+
+  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+  // 2556. Wide contract for future::share()
+  template<typename _Res>
+    inline shared_future<_Res>
+    future<_Res>::share() noexcept
+    { return shared_future<_Res>(std::move(*this)); }
+
+  template<typename _Res>
+    inline shared_future<_Res&>
+    future<_Res&>::share() noexcept
+    { return shared_future<_Res&>(std::move(*this)); }
+
+  inline shared_future<void>
+  future<void>::share() noexcept
+  { return shared_future<void>(std::move(*this)); }
+
+  /// Primary template for promise
+  template<typename _Res>
+    class promise
+    {
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 3466: Specify the requirements for promise/future/[...] consistently
+      static_assert(!is_array<_Res>{}, "result type must not be an array");
+      static_assert(!is_function<_Res>{}, "result type must not be a function");
+      static_assert(is_destructible<_Res>{},
+		    "result type must be destructible");
+
+      typedef __future_base::_State_base 	_State;
+      typedef __future_base::_Result<_Res>	_Res_type;
+      typedef __future_base::_Ptr<_Res_type>	_Ptr_type;
+      template<typename, typename> friend struct _State::_Setter;
+      friend _State;
+
+      shared_ptr<_State>                        _M_future;
+      _Ptr_type                                 _M_storage;
+
+    public:
+      promise()
+      : _M_future(std::make_shared<_State>()),
+	_M_storage(new _Res_type())
+      { }
+
+      promise(promise&& __rhs) noexcept
+      : _M_future(std::move(__rhs._M_future)),
+	_M_storage(std::move(__rhs._M_storage))
+      { }
+
+      template<typename _Allocator>
+        promise(allocator_arg_t, const _Allocator& __a)
+        : _M_future(std::allocate_shared<_State>(__a)),
+	  _M_storage(__future_base::_S_allocate_result<_Res>(__a))
+        { }
+
+      template<typename _Allocator>
+        promise(allocator_arg_t, const _Allocator&, promise&& __rhs)
+        : _M_future(std::move(__rhs._M_future)),
+	  _M_storage(std::move(__rhs._M_storage))
+        { }
+
+      promise(const promise&) = delete;
+
+      ~promise()
+      {
+        if (static_cast<bool>(_M_future) && !_M_future.unique())
+          _M_future->_M_break_promise(std::move(_M_storage));
+      }
+
+      // Assignment
+      promise&
+      operator=(promise&& __rhs) noexcept
+      {
+        promise(std::move(__rhs)).swap(*this);
+        return *this;
+      }
+
+      promise& operator=(const promise&) = delete;
+
+      void
+      swap(promise& __rhs) noexcept
+      {
+        _M_future.swap(__rhs._M_future);
+        _M_storage.swap(__rhs._M_storage);
+      }
+
+      // Retrieving the result
+      future<_Res>
+      get_future()
+      { return future<_Res>(_M_future); }
+
+      // Setting the result
+      void
+      set_value(const _Res& __r)
+      { _M_state()._M_set_result(_State::__setter(this, __r)); }
+
+      void
+      set_value(_Res&& __r)
+      { _M_state()._M_set_result(_State::__setter(this, std::move(__r))); }
+
+      void
+      set_exception(exception_ptr __p)
+      { _M_state()._M_set_result(_State::__setter(__p, this)); }
+
+      void
+      set_value_at_thread_exit(const _Res& __r)
+      {
+	_M_state()._M_set_delayed_result(_State::__setter(this, __r),
+					 _M_future);
+      }
+
+      void
+      set_value_at_thread_exit(_Res&& __r)
+      {
+	_M_state()._M_set_delayed_result(
+	    _State::__setter(this, std::move(__r)), _M_future);
+      }
+
+      void
+      set_exception_at_thread_exit(exception_ptr __p)
+      {
+	_M_state()._M_set_delayed_result(_State::__setter(__p, this),
+					 _M_future);
+      }
+
+    private:
+      _State&
+      _M_state()
+      {
+	__future_base::_State_base::_S_check(_M_future);
+	return *_M_future;
+      }
+    };
+
+  template<typename _Res>
+    inline void
+    swap(promise<_Res>& __x, promise<_Res>& __y) noexcept
+    { __x.swap(__y); }
+
+  template<typename _Res, typename _Alloc>
+    struct uses_allocator<promise<_Res>, _Alloc>
+    : public true_type { };
+
+
+  /// Partial specialization for promise<R&>
+  template<typename _Res>
+    class promise<_Res&>
+    {
+      typedef __future_base::_State_base	_State;
+      typedef __future_base::_Result<_Res&>	_Res_type;
+      typedef __future_base::_Ptr<_Res_type> 	_Ptr_type;
+      template<typename, typename> friend struct _State::_Setter;
+      friend _State;
+
+      shared_ptr<_State>                        _M_future;
+      _Ptr_type                                 _M_storage;
+
+    public:
+      promise()
+      : _M_future(std::make_shared<_State>()),
+	_M_storage(new _Res_type())
+      { }
+
+      promise(promise&& __rhs) noexcept
+      : _M_future(std::move(__rhs._M_future)),
+	_M_storage(std::move(__rhs._M_storage))
+      { }
+
+      template<typename _Allocator>
+        promise(allocator_arg_t, const _Allocator& __a)
+        : _M_future(std::allocate_shared<_State>(__a)),
+	  _M_storage(__future_base::_S_allocate_result<_Res&>(__a))
+        { }
+
+      template<typename _Allocator>
+        promise(allocator_arg_t, const _Allocator&, promise&& __rhs)
+        : _M_future(std::move(__rhs._M_future)),
+	  _M_storage(std::move(__rhs._M_storage))
+        { }
+
+      promise(const promise&) = delete;
+
+      ~promise()
+      {
+        if (static_cast<bool>(_M_future) && !_M_future.unique())
+          _M_future->_M_break_promise(std::move(_M_storage));
+      }
+
+      // Assignment
+      promise&
+      operator=(promise&& __rhs) noexcept
+      {
+        promise(std::move(__rhs)).swap(*this);
+        return *this;
+      }
+
+      promise& operator=(const promise&) = delete;
+
+      void
+      swap(promise& __rhs) noexcept
+      {
+        _M_future.swap(__rhs._M_future);
+        _M_storage.swap(__rhs._M_storage);
+      }
+
+      // Retrieving the result
+      future<_Res&>
+      get_future()
+      { return future<_Res&>(_M_future); }
+
+      // Setting the result
+      void
+      set_value(_Res& __r)
+      { _M_state()._M_set_result(_State::__setter(this, __r)); }
+
+      void
+      set_exception(exception_ptr __p)
+      { _M_state()._M_set_result(_State::__setter(__p, this)); }
+
+      void
+      set_value_at_thread_exit(_Res& __r)
+      {
+	_M_state()._M_set_delayed_result(_State::__setter(this, __r),
+					 _M_future);
+      }
+
+      void
+      set_exception_at_thread_exit(exception_ptr __p)
+      {
+	_M_state()._M_set_delayed_result(_State::__setter(__p, this),
+					 _M_future);
+      }
+
+    private:
+      _State&
+      _M_state()
+      {
+	__future_base::_State_base::_S_check(_M_future);
+	return *_M_future;
+      }
+    };
+
+  /// Explicit specialization for promise<void>
+  template<>
+    class promise<void>
+    {
+      typedef __future_base::_State_base	_State;
+      typedef __future_base::_Result<void>	_Res_type;
+      typedef __future_base::_Ptr<_Res_type> 	_Ptr_type;
+      template<typename, typename> friend struct _State::_Setter;
+      friend _State;
+
+      shared_ptr<_State>                        _M_future;
+      _Ptr_type                                 _M_storage;
+
+    public:
+      promise()
+      : _M_future(std::make_shared<_State>()),
+	_M_storage(new _Res_type())
+      { }
+
+      promise(promise&& __rhs) noexcept
+      : _M_future(std::move(__rhs._M_future)),
+	_M_storage(std::move(__rhs._M_storage))
+      { }
+
+      template<typename _Allocator>
+        promise(allocator_arg_t, const _Allocator& __a)
+        : _M_future(std::allocate_shared<_State>(__a)),
+	  _M_storage(__future_base::_S_allocate_result<void>(__a))
+        { }
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 2095.  missing constructors needed for uses-allocator construction
+      template<typename _Allocator>
+        promise(allocator_arg_t, const _Allocator&, promise&& __rhs)
+        : _M_future(std::move(__rhs._M_future)),
+	  _M_storage(std::move(__rhs._M_storage))
+        { }
+
+      promise(const promise&) = delete;
+
+      ~promise()
+      {
+        if (static_cast<bool>(_M_future) && !_M_future.unique())
+          _M_future->_M_break_promise(std::move(_M_storage));
+      }
+
+      // Assignment
+      promise&
+      operator=(promise&& __rhs) noexcept
+      {
+        promise(std::move(__rhs)).swap(*this);
+        return *this;
+      }
+
+      promise& operator=(const promise&) = delete;
+
+      void
+      swap(promise& __rhs) noexcept
+      {
+        _M_future.swap(__rhs._M_future);
+        _M_storage.swap(__rhs._M_storage);
+      }
+
+      // Retrieving the result
+      future<void>
+      get_future()
+      { return future<void>(_M_future); }
+
+      // Setting the result
+      void
+      set_value()
+      { _M_state()._M_set_result(_State::__setter(this)); }
+
+      void
+      set_exception(exception_ptr __p)
+      { _M_state()._M_set_result(_State::__setter(__p, this)); }
+
+      void
+      set_value_at_thread_exit()
+      { _M_state()._M_set_delayed_result(_State::__setter(this), _M_future); }
+
+      void
+      set_exception_at_thread_exit(exception_ptr __p)
+      {
+	_M_state()._M_set_delayed_result(_State::__setter(__p, this),
+					 _M_future);
+      }
+
+    private:
+      _State&
+      _M_state()
+      {
+	__future_base::_State_base::_S_check(_M_future);
+	return *_M_future;
+      }
+    };
+
+  template<typename _Ptr_type, typename _Fn, typename _Res>
+    struct __future_base::_Task_setter
+    {
+      // Invoke the function and provide the result to the caller.
+      _Ptr_type operator()() const
+      {
+	__try
+	  {
+	    (*_M_result)->_M_set((*_M_fn)());
+	  }
+	__catch(const __cxxabiv1::__forced_unwind&)
+	  {
+	    __throw_exception_again; // will cause broken_promise
+	  }
+	__catch(...)
+	  {
+	    (*_M_result)->_M_error = current_exception();
+	  }
+	return std::move(*_M_result);
+      }
+      _Ptr_type*	_M_result;
+      _Fn*		_M_fn;
+    };
+
+  template<typename _Ptr_type, typename _Fn>
+    struct __future_base::_Task_setter<_Ptr_type, _Fn, void>
+    {
+      _Ptr_type operator()() const
+      {
+	__try
+	  {
+	    (*_M_fn)();
+	  }
+	__catch(const __cxxabiv1::__forced_unwind&)
+	  {
+	    __throw_exception_again; // will cause broken_promise
+	  }
+	__catch(...)
+	  {
+	    (*_M_result)->_M_error = current_exception();
+	  }
+	return std::move(*_M_result);
+      }
+      _Ptr_type*	_M_result;
+      _Fn*		_M_fn;
+    };
+
+  // Holds storage for a packaged_task's result.
+  template<typename _Res, typename... _Args>
+    struct __future_base::_Task_state_base<_Res(_Args...)>
+    : __future_base::_State_base
+    {
+      typedef _Res _Res_type;
+
+      template<typename _Alloc>
+	_Task_state_base(const _Alloc& __a)
+	: _M_result(_S_allocate_result<_Res>(__a))
+	{ }
+
+      // Invoke the stored task and make the state ready.
+      virtual void
+      _M_run(_Args&&... __args) = 0;
+
+      // Invoke the stored task and make the state ready at thread exit.
+      virtual void
+      _M_run_delayed(_Args&&... __args, weak_ptr<_State_base>) = 0;
+
+      virtual shared_ptr<_Task_state_base>
+      _M_reset() = 0;
+
+      typedef __future_base::_Ptr<_Result<_Res>> _Ptr_type;
+      _Ptr_type _M_result;
+    };
+
+  // Holds a packaged_task's stored task.
+  template<typename _Fn, typename _Alloc, typename _Res, typename... _Args>
+    struct __future_base::_Task_state<_Fn, _Alloc, _Res(_Args...)> final
+    : __future_base::_Task_state_base<_Res(_Args...)>
+    {
+      template<typename _Fn2>
+	_Task_state(_Fn2&& __fn, const _Alloc& __a)
+	: _Task_state_base<_Res(_Args...)>(__a),
+	  _M_impl(std::forward<_Fn2>(__fn), __a)
+	{ }
+
+    private:
+      virtual void
+      _M_run(_Args&&... __args)
+      {
+	auto __boundfn = [&] () -> _Res {
+	    return std::__invoke_r<_Res>(_M_impl._M_fn,
+					 std::forward<_Args>(__args)...);
+	};
+	this->_M_set_result(_S_task_setter(this->_M_result, __boundfn));
+      }
+
+      virtual void
+      _M_run_delayed(_Args&&... __args, weak_ptr<_State_base> __self)
+      {
+	auto __boundfn = [&] () -> _Res {
+	    return std::__invoke_r<_Res>(_M_impl._M_fn,
+					 std::forward<_Args>(__args)...);
+	};
+	this->_M_set_delayed_result(_S_task_setter(this->_M_result, __boundfn),
+				    std::move(__self));
+      }
+
+      virtual shared_ptr<_Task_state_base<_Res(_Args...)>>
+      _M_reset();
+
+      struct _Impl : _Alloc
+      {
+	template<typename _Fn2>
+	  _Impl(_Fn2&& __fn, const _Alloc& __a)
+	  : _Alloc(__a), _M_fn(std::forward<_Fn2>(__fn)) { }
+	_Fn _M_fn;
+      } _M_impl;
+    };
+
+  template<typename _Signature, typename _Fn,
+	   typename _Alloc = std::allocator<int>>
+    static shared_ptr<__future_base::_Task_state_base<_Signature>>
+    __create_task_state(_Fn&& __fn, const _Alloc& __a = _Alloc())
+    {
+      typedef typename decay<_Fn>::type _Fn2;
+      typedef __future_base::_Task_state<_Fn2, _Alloc, _Signature> _State;
+      return std::allocate_shared<_State>(__a, std::forward<_Fn>(__fn), __a);
+    }
+
+  template<typename _Fn, typename _Alloc, typename _Res, typename... _Args>
+    shared_ptr<__future_base::_Task_state_base<_Res(_Args...)>>
+    __future_base::_Task_state<_Fn, _Alloc, _Res(_Args...)>::_M_reset()
+    {
+      return __create_task_state<_Res(_Args...)>(std::move(_M_impl._M_fn),
+						 static_cast<_Alloc&>(_M_impl));
+    }
+
+  /// packaged_task
+  template<typename _Res, typename... _ArgTypes>
+    class packaged_task<_Res(_ArgTypes...)>
+    {
+      typedef __future_base::_Task_state_base<_Res(_ArgTypes...)> _State_type;
+      shared_ptr<_State_type>                   _M_state;
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 3039. Unnecessary decay in thread and packaged_task
+      template<typename _Fn, typename _Fn2 = __remove_cvref_t<_Fn>>
+	using __not_same
+	  = typename enable_if<!is_same<packaged_task, _Fn2>::value>::type;
+
+    public:
+      // Construction and destruction
+      packaged_task() noexcept { }
+
+      template<typename _Fn, typename = __not_same<_Fn>>
+	explicit
+	packaged_task(_Fn&& __fn)
+	: _M_state(
+	    __create_task_state<_Res(_ArgTypes...)>(std::forward<_Fn>(__fn)))
+	{ }
+
+#if __cplusplus < 201703L
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 2097. packaged_task constructors should be constrained
+      // 2407. [this constructor should not be] explicit
+      // 2921. packaged_task and type-erased allocators
+      template<typename _Fn, typename _Alloc, typename = __not_same<_Fn>>
+	packaged_task(allocator_arg_t, const _Alloc& __a, _Fn&& __fn)
+	: _M_state(__create_task_state<_Res(_ArgTypes...)>(
+		   std::forward<_Fn>(__fn), __a))
+	{ }
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 2095.  missing constructors needed for uses-allocator construction
+      template<typename _Allocator>
+	packaged_task(allocator_arg_t, const _Allocator& __a) noexcept
+	{ }
+
+      template<typename _Allocator>
+	packaged_task(allocator_arg_t, const _Allocator&,
+		      const packaged_task&) = delete;
+
+      template<typename _Allocator>
+	packaged_task(allocator_arg_t, const _Allocator&,
+		      packaged_task&& __other) noexcept
+	{ this->swap(__other); }
+#endif
+
+      ~packaged_task()
+      {
+        if (static_cast<bool>(_M_state) && !_M_state.unique())
+	  _M_state->_M_break_promise(std::move(_M_state->_M_result));
+      }
+
+      // No copy
+      packaged_task(const packaged_task&) = delete;
+      packaged_task& operator=(const packaged_task&) = delete;
+
+      // Move support
+      packaged_task(packaged_task&& __other) noexcept
+      { this->swap(__other); }
+
+      packaged_task& operator=(packaged_task&& __other) noexcept
+      {
+	packaged_task(std::move(__other)).swap(*this);
+	return *this;
+      }
+
+      void
+      swap(packaged_task& __other) noexcept
+      { _M_state.swap(__other._M_state); }
+
+      bool
+      valid() const noexcept
+      { return static_cast<bool>(_M_state); }
+
+      // Result retrieval
+      future<_Res>
+      get_future()
+      { return future<_Res>(_M_state); }
+
+      // Execution
+      void
+      operator()(_ArgTypes... __args)
+      {
+	__future_base::_State_base::_S_check(_M_state);
+	_M_state->_M_run(std::forward<_ArgTypes>(__args)...);
+      }
+
+      void
+      make_ready_at_thread_exit(_ArgTypes... __args)
+      {
+	__future_base::_State_base::_S_check(_M_state);
+	_M_state->_M_run_delayed(std::forward<_ArgTypes>(__args)..., _M_state);
+      }
+
+      void
+      reset()
+      {
+	__future_base::_State_base::_S_check(_M_state);
+	packaged_task __tmp;
+	__tmp._M_state = _M_state;
+	_M_state = _M_state->_M_reset();
+      }
+    };
+
+  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+  // 3117. Missing packaged_task deduction guides
+#if __cpp_deduction_guides >= 201606
+  template<typename _Res, typename... _ArgTypes>
+    packaged_task(_Res(*)(_ArgTypes...)) -> packaged_task<_Res(_ArgTypes...)>;
+
+  template<typename _Fun, typename _Signature = typename
+	   __function_guide_helper<decltype(&_Fun::operator())>::type>
+    packaged_task(_Fun) -> packaged_task<_Signature>;
+#endif
+
+  /// swap
+  template<typename _Res, typename... _ArgTypes>
+    inline void
+    swap(packaged_task<_Res(_ArgTypes...)>& __x,
+	 packaged_task<_Res(_ArgTypes...)>& __y) noexcept
+    { __x.swap(__y); }
+
+#if __cplusplus < 201703L
+  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+  // 2976. Dangling uses_allocator specialization for packaged_task
+  template<typename _Res, typename _Alloc>
+    struct uses_allocator<packaged_task<_Res>, _Alloc>
+    : public true_type { };
+#endif
+
+  // Shared state created by std::async().
+  // Holds a deferred function and storage for its result.
+  template<typename _BoundFn, typename _Res>
+    class __future_base::_Deferred_state final
+    : public __future_base::_State_base
+    {
+    public:
+      template<typename... _Args>
+	explicit
+	_Deferred_state(_Args&&... __args)
+	: _M_result(new _Result<_Res>()),
+	  _M_fn{{std::forward<_Args>(__args)...}}
+	{ }
+
+    private:
+      typedef __future_base::_Ptr<_Result<_Res>> _Ptr_type;
+      _Ptr_type _M_result;
+      _BoundFn _M_fn;
+
+      // Run the deferred function.
+      virtual void
+      _M_complete_async()
+      {
+	// Multiple threads can call a waiting function on the future and
+	// reach this point at the same time. The call_once in _M_set_result
+	// ensures only the first one run the deferred function, stores the
+	// result in _M_result, swaps that with the base _M_result and makes
+	// the state ready. Tell _M_set_result to ignore failure so all later
+	// calls do nothing.
+        _M_set_result(_S_task_setter(_M_result, _M_fn), true);
+      }
+
+      // Caller should check whether the state is ready first, because this
+      // function will return true even after the deferred function has run.
+      virtual bool _M_is_deferred_future() const { return true; }
+    };
+
+  // Common functionality hoisted out of the _Async_state_impl template.
+  class __future_base::_Async_state_commonV2
+    : public __future_base::_State_base
+  {
+  protected:
+    ~_Async_state_commonV2() = default;
+
+    // Make waiting functions block until the thread completes, as if joined.
+    //
+    // This function is used by wait() to satisfy the first requirement below
+    // and by wait_for() / wait_until() to satisfy the second.
+    //
+    // [futures.async]:
+    //
+    // - a call to a waiting function on an asynchronous return object that
+    // shares the shared state created by this async call shall block until
+    // the associated thread has completed, as if joined, or else time out.
+    //
+    // - the associated thread completion synchronizes with the return from
+    // the first function that successfully detects the ready status of the
+    // shared state or with the return from the last function that releases
+    // the shared state, whichever happens first.
+    virtual void _M_complete_async() { _M_join(); }
+
+    void _M_join() { std::call_once(_M_once, &thread::join, &_M_thread); }
+
+    thread _M_thread;
+    once_flag _M_once;
+  };
+
+  // Shared state created by std::async().
+  // Starts a new thread that runs a function and makes the shared state ready.
+  template<typename _BoundFn, typename _Res>
+    class __future_base::_Async_state_impl final
+    : public __future_base::_Async_state_commonV2
+    {
+    public:
+      template<typename... _Args>
+	explicit
+	_Async_state_impl(_Args&&... __args)
+	: _M_result(new _Result<_Res>()),
+	  _M_fn{{std::forward<_Args>(__args)...}}
+	{
+	  _M_thread = std::thread{&_Async_state_impl::_M_run, this};
+	}
+
+      // Must not destroy _M_result and _M_fn until the thread finishes.
+      // Call join() directly rather than through _M_join() because no other
+      // thread can be referring to this state if it is being destroyed.
+      ~_Async_state_impl()
+      {
+	if (_M_thread.joinable())
+	  _M_thread.join();
+      }
+
+    private:
+      void
+      _M_run()
+      {
+	__try
+	  {
+	    _M_set_result(_S_task_setter(_M_result, _M_fn));
+	  }
+	__catch (const __cxxabiv1::__forced_unwind&)
+	  {
+	    // make the shared state ready on thread cancellation
+	    if (static_cast<bool>(_M_result))
+	      this->_M_break_promise(std::move(_M_result));
+	    __throw_exception_again;
+	  }
+      }
+
+      typedef __future_base::_Ptr<_Result<_Res>> _Ptr_type;
+      _Ptr_type _M_result;
+      _BoundFn _M_fn;
+    };
+
+
+  /// async
+  template<typename _Fn, typename... _Args>
+    _GLIBCXX_NODISCARD future<__async_result_of<_Fn, _Args...>>
+    async(launch __policy, _Fn&& __fn, _Args&&... __args)
+    {
+      using _Wr = std::thread::_Call_wrapper<_Fn, _Args...>;
+      using _As = __future_base::_Async_state_impl<_Wr>;
+      using _Ds = __future_base::_Deferred_state<_Wr>;
+
+      std::shared_ptr<__future_base::_State_base> __state;
+      if ((__policy & launch::async) == launch::async)
+	{
+	  __try
+	    {
+	      __state = std::make_shared<_As>(std::forward<_Fn>(__fn),
+					      std::forward<_Args>(__args)...);
+	    }
+#if __cpp_exceptions
+	  catch(const system_error& __e)
+	    {
+	      if (__e.code() != errc::resource_unavailable_try_again
+		  || (__policy & launch::deferred) != launch::deferred)
+		throw;
+	    }
+#endif
+	}
+      if (!__state)
+	{
+	  __state = std::make_shared<_Ds>(std::forward<_Fn>(__fn),
+					  std::forward<_Args>(__args)...);
+	}
+      return future<__async_result_of<_Fn, _Args...>>(std::move(__state));
+    }
+
+  /// async, potential overload
+  template<typename _Fn, typename... _Args>
+    _GLIBCXX_NODISCARD inline future<__async_result_of<_Fn, _Args...>>
+    async(_Fn&& __fn, _Args&&... __args)
+    {
+      return std::async(launch::async|launch::deferred,
+			std::forward<_Fn>(__fn),
+			std::forward<_Args>(__args)...);
+    }
+
+#endif // _GLIBCXX_ASYNC_ABI_COMPAT
+#endif // _GLIBCXX_HAS_GTHREADS
+
+  /// @} group futures
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif // C++11
+
+#endif // _GLIBCXX_FUTURE
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@future.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@future.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@initializer_list b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@initializer_list
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@initializer_list
@@ -0,0 +1,109 @@
+// std::initializer_list support -*- C++ -*-
+
+// Copyright (C) 2008-2022 Free Software Foundation, Inc.
+//
+// This file is part of GCC.
+//
+// GCC is free software; you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation; either version 3, or (at your option)
+// any later version.
+//
+// GCC is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file initializer_list
+ *  This is a Standard C++ Library header.
+ */
+
+#ifndef _INITIALIZER_LIST
+#define _INITIALIZER_LIST
+
+#pragma GCC system_header
+
+#if __cplusplus < 201103L
+# include <bits/c++0x_warning.h>
+#else // C++0x
+
+#pragma GCC visibility push(default)
+
+#include <bits/c++config.h>
+
+namespace std
+{
+  /// initializer_list
+  template<class _E>
+    class initializer_list
+    {
+    public:
+      typedef _E 		value_type;
+      typedef const _E& 	reference;
+      typedef const _E& 	const_reference;
+      typedef size_t 		size_type;
+      typedef const _E* 	iterator;
+      typedef const _E* 	const_iterator;
+
+    private:
+      iterator			_M_array;
+      size_type			_M_len;
+
+      // The compiler can call a private constructor.
+      constexpr initializer_list(const_iterator __a, size_type __l)
+      : _M_array(__a), _M_len(__l) { }
+
+    public:
+      constexpr initializer_list() noexcept
+      : _M_array(0), _M_len(0) { }
+
+      // Number of elements.
+      constexpr size_type
+      size() const noexcept { return _M_len; }
+
+      // First element.
+      constexpr const_iterator
+      begin() const noexcept { return _M_array; }
+
+      // One past the last element.
+      constexpr const_iterator
+      end() const noexcept { return begin() + size(); }
+    };
+
+  /**
+   *  @brief  Return an iterator pointing to the first element of
+   *          the initializer_list.
+   *  @param  __ils  Initializer list.
+   *  @relates initializer_list
+   */
+  template<class _Tp>
+    constexpr const _Tp*
+    begin(initializer_list<_Tp> __ils) noexcept
+    { return __ils.begin(); }
+
+  /**
+   *  @brief  Return an iterator pointing to one past the last element
+   *          of the initializer_list.
+   *  @param  __ils  Initializer list.
+   *  @relates initializer_list
+   */
+  template<class _Tp>
+    constexpr const _Tp*
+    end(initializer_list<_Tp> __ils) noexcept
+    { return __ils.end(); }
+}
+
+#pragma GCC visibility pop
+
+#endif // C++11
+
+#endif // _INITIALIZER_LIST
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@iomanip b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@iomanip
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@@ -0,0 +1,540 @@
+// Standard stream manipulators -*- C++ -*-
+
+// Copyright (C) 1997-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file include/iomanip
+ *  This is a Standard C++ Library header.
+ */
+
+//
+// ISO C++ 14882: 27.6.3  Standard manipulators
+//
+
+#ifndef _GLIBCXX_IOMANIP
+#define _GLIBCXX_IOMANIP 1
+
+#pragma GCC system_header
+
+#include <bits/c++config.h>
+#include <iosfwd>
+#include <bits/ios_base.h>
+
+#if __cplusplus >= 201103L
+#include <locale>
+#if __cplusplus > 201103L
+#include <bits/quoted_string.h>
+#endif
+#endif
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  // [27.6.3] standard manipulators
+  // Also see DR 183.
+
+  struct _Resetiosflags { ios_base::fmtflags _M_mask; };
+
+  /**
+   *  @brief  Manipulator for @c setf.
+   *  @param  __mask  A format flags mask.
+   *
+   *  Sent to a stream object, this manipulator resets the specified flags,
+   *  via @e stream.setf(0,__mask).
+  */
+  inline _Resetiosflags
+  resetiosflags(ios_base::fmtflags __mask)
+  { return { __mask }; }
+
+  template<typename _CharT, typename _Traits>
+    inline basic_istream<_CharT, _Traits>&
+    operator>>(basic_istream<_CharT, _Traits>& __is, _Resetiosflags __f)
+    {
+      __is.setf(ios_base::fmtflags(0), __f._M_mask);
+      return __is;
+    }
+
+  template<typename _CharT, typename _Traits>
+    inline basic_ostream<_CharT, _Traits>&
+    operator<<(basic_ostream<_CharT, _Traits>& __os, _Resetiosflags __f)
+    {
+      __os.setf(ios_base::fmtflags(0), __f._M_mask);
+      return __os;
+    }
+
+
+  struct _Setiosflags { ios_base::fmtflags _M_mask; };
+
+  /**
+   *  @brief  Manipulator for @c setf.
+   *  @param  __mask  A format flags mask.
+   *
+   *  Sent to a stream object, this manipulator sets the format flags
+   *  to @a __mask.
+  */
+  inline _Setiosflags
+  setiosflags(ios_base::fmtflags __mask)
+  { return { __mask }; }
+
+  template<typename _CharT, typename _Traits>
+    inline basic_istream<_CharT, _Traits>&
+    operator>>(basic_istream<_CharT, _Traits>& __is, _Setiosflags __f)
+    {
+      __is.setf(__f._M_mask);
+      return __is;
+    }
+
+  template<typename _CharT, typename _Traits>
+    inline basic_ostream<_CharT, _Traits>&
+    operator<<(basic_ostream<_CharT, _Traits>& __os, _Setiosflags __f)
+    {
+      __os.setf(__f._M_mask);
+      return __os;
+    }
+
+
+  struct _Setbase { int _M_base; };
+
+  /**
+   *  @brief  Manipulator for @c setf.
+   *  @param  __base  A numeric base.
+   *
+   *  Sent to a stream object, this manipulator changes the
+   *  @c ios_base::basefield flags to @c oct, @c dec, or @c hex when @a base
+   *  is 8, 10, or 16, accordingly, and to 0 if @a __base is any other value.
+  */
+  inline _Setbase
+  setbase(int __base)
+  { return { __base }; }
+
+  template<typename _CharT, typename _Traits>
+    inline basic_istream<_CharT, _Traits>&
+    operator>>(basic_istream<_CharT, _Traits>& __is, _Setbase __f)
+    {
+      __is.setf(__f._M_base ==  8 ? ios_base::oct :
+		__f._M_base == 10 ? ios_base::dec :
+		__f._M_base == 16 ? ios_base::hex :
+		ios_base::fmtflags(0), ios_base::basefield);
+      return __is;
+    }
+
+  template<typename _CharT, typename _Traits>
+    inline basic_ostream<_CharT, _Traits>&
+    operator<<(basic_ostream<_CharT, _Traits>& __os, _Setbase __f)
+    {
+      __os.setf(__f._M_base ==  8 ? ios_base::oct :
+		__f._M_base == 10 ? ios_base::dec :
+		__f._M_base == 16 ? ios_base::hex :
+		ios_base::fmtflags(0), ios_base::basefield);
+      return __os;
+    }
+
+
+  template<typename _CharT>
+    struct _Setfill { _CharT _M_c; };
+
+  /**
+   *  @brief  Manipulator for @c fill.
+   *  @param  __c  The new fill character.
+   *
+   *  Sent to a stream object, this manipulator calls @c fill(__c) for that
+   *  object.
+  */
+  template<typename _CharT>
+    inline _Setfill<_CharT>
+    setfill(_CharT __c)
+    { return { __c }; }
+
+  template<typename _CharT, typename _Traits>
+    inline basic_istream<_CharT, _Traits>&
+    operator>>(basic_istream<_CharT, _Traits>& __is, _Setfill<_CharT> __f)
+    {
+      __is.fill(__f._M_c);
+      return __is;
+    }
+
+  template<typename _CharT, typename _Traits>
+    inline basic_ostream<_CharT, _Traits>&
+    operator<<(basic_ostream<_CharT, _Traits>& __os, _Setfill<_CharT> __f)
+    {
+      __os.fill(__f._M_c);
+      return __os;
+    }
+
+
+  struct _Setprecision { int _M_n; };
+
+  /**
+   *  @brief  Manipulator for @c precision.
+   *  @param  __n  The new precision.
+   *
+   *  Sent to a stream object, this manipulator calls @c precision(__n) for
+   *  that object.
+  */
+  inline _Setprecision
+  setprecision(int __n)
+  { return { __n }; }
+
+  template<typename _CharT, typename _Traits>
+    inline basic_istream<_CharT, _Traits>&
+    operator>>(basic_istream<_CharT, _Traits>& __is, _Setprecision __f)
+    {
+      __is.precision(__f._M_n);
+      return __is;
+    }
+
+  template<typename _CharT, typename _Traits>
+    inline basic_ostream<_CharT, _Traits>&
+    operator<<(basic_ostream<_CharT, _Traits>& __os, _Setprecision __f)
+    {
+      __os.precision(__f._M_n);
+      return __os;
+    }
+
+
+  struct _Setw { int _M_n; };
+
+  /**
+   *  @brief  Manipulator for @c width.
+   *  @param  __n  The new width.
+   *
+   *  Sent to a stream object, this manipulator calls @c width(__n) for
+   *  that object.
+  */
+  inline _Setw
+  setw(int __n)
+  { return { __n }; }
+
+  template<typename _CharT, typename _Traits>
+    inline basic_istream<_CharT, _Traits>&
+    operator>>(basic_istream<_CharT, _Traits>& __is, _Setw __f)
+    {
+      __is.width(__f._M_n);
+      return __is;
+    }
+
+  template<typename _CharT, typename _Traits>
+    inline basic_ostream<_CharT, _Traits>&
+    operator<<(basic_ostream<_CharT, _Traits>& __os, _Setw __f)
+    {
+      __os.width(__f._M_n);
+      return __os;
+    }
+
+#if __cplusplus >= 201103L
+
+  template<typename _MoneyT>
+    struct _Get_money { _MoneyT& _M_mon; bool _M_intl; };
+
+  /**
+   *  @brief  Extended manipulator for extracting money.
+   *  @param  __mon  Either long double or a specialization of @c basic_string.
+   *  @param  __intl A bool indicating whether international format
+   *                 is to be used.
+   *
+   *  Sent to a stream object, this manipulator extracts @a __mon.
+  */
+  template<typename _MoneyT>
+    inline _Get_money<_MoneyT>
+    get_money(_MoneyT& __mon, bool __intl = false)
+    { return { __mon, __intl }; }
+
+  template<typename _CharT, typename _Traits, typename _MoneyT>
+    basic_istream<_CharT, _Traits>&
+    operator>>(basic_istream<_CharT, _Traits>& __is, _Get_money<_MoneyT> __f)
+    {
+      typename basic_istream<_CharT, _Traits>::sentry __cerb(__is, false);
+      if (__cerb)
+	{
+	  ios_base::iostate __err = ios_base::goodbit;
+	  __try
+	    {
+	      typedef istreambuf_iterator<_CharT, _Traits>   _Iter;
+	      typedef money_get<_CharT, _Iter>               _MoneyGet;
+
+	      const _MoneyGet& __mg = use_facet<_MoneyGet>(__is.getloc());
+	      __mg.get(_Iter(__is.rdbuf()), _Iter(), __f._M_intl,
+		       __is, __err, __f._M_mon);
+	    }
+	  __catch(__cxxabiv1::__forced_unwind&)
+	    {
+	      __is._M_setstate(ios_base::badbit);
+	      __throw_exception_again;
+	    }
+	  __catch(...)
+	    { __is._M_setstate(ios_base::badbit); }
+	  if (__err)
+	    __is.setstate(__err);
+	}
+      return __is;
+    }
+
+
+  template<typename _MoneyT>
+    struct _Put_money { const _MoneyT& _M_mon; bool _M_intl; };
+
+  /**
+   *  @brief  Extended manipulator for inserting money.
+   *  @param  __mon  Either long double or a specialization of @c basic_string.
+   *  @param  __intl A bool indicating whether international format
+   *                 is to be used.
+   *
+   *  Sent to a stream object, this manipulator inserts @a __mon.
+  */
+  template<typename _MoneyT>
+    inline _Put_money<_MoneyT>
+    put_money(const _MoneyT& __mon, bool __intl = false)
+    { return { __mon, __intl }; }
+
+  template<typename _CharT, typename _Traits, typename _MoneyT>
+    basic_ostream<_CharT, _Traits>&
+    operator<<(basic_ostream<_CharT, _Traits>& __os, _Put_money<_MoneyT> __f)
+    {
+      typename basic_ostream<_CharT, _Traits>::sentry __cerb(__os);
+      if (__cerb)
+	{
+	  ios_base::iostate __err = ios_base::goodbit;
+	  __try
+	    {
+	      typedef ostreambuf_iterator<_CharT, _Traits>   _Iter;
+	      typedef money_put<_CharT, _Iter>               _MoneyPut;
+
+	      const _MoneyPut& __mp = use_facet<_MoneyPut>(__os.getloc());
+	      if (__mp.put(_Iter(__os.rdbuf()), __f._M_intl, __os,
+			   __os.fill(), __f._M_mon).failed())
+		__err |= ios_base::badbit;
+	    }
+	  __catch(__cxxabiv1::__forced_unwind&)
+	    {
+	      __os._M_setstate(ios_base::badbit);
+	      __throw_exception_again;
+	    }
+	  __catch(...)
+	    { __os._M_setstate(ios_base::badbit); }
+	  if (__err)
+	    __os.setstate(__err);
+	}
+      return __os;
+    }
+
+  template<typename _CharT>
+    struct _Put_time
+    {
+      const std::tm* _M_tmb;
+      const _CharT* _M_fmt;
+    };
+
+  /**
+   *  @brief  Extended manipulator for formatting time.
+   *
+   *  This manipulator uses time_put::put to format time.
+   *  [ext.manip]
+   *
+   *  @param __tmb  struct tm time data to format.
+   *  @param __fmt  format string.
+   */
+  template<typename _CharT>
+    inline _Put_time<_CharT>
+    put_time(const std::tm* __tmb, const _CharT* __fmt)
+    { return { __tmb, __fmt }; }
+
+  template<typename _CharT, typename _Traits>
+    basic_ostream<_CharT, _Traits>&
+    operator<<(basic_ostream<_CharT, _Traits>& __os, _Put_time<_CharT> __f)
+    {
+      typename basic_ostream<_CharT, _Traits>::sentry __cerb(__os);
+      if (__cerb)
+        {
+          ios_base::iostate __err = ios_base::goodbit;
+          __try
+            {
+              typedef ostreambuf_iterator<_CharT, _Traits>   _Iter;
+              typedef time_put<_CharT, _Iter>                _TimePut;
+
+              const _CharT* const __fmt_end = __f._M_fmt +
+                _Traits::length(__f._M_fmt);
+
+              const _TimePut& __mp = use_facet<_TimePut>(__os.getloc());
+              if (__mp.put(_Iter(__os.rdbuf()), __os, __os.fill(),
+                           __f._M_tmb, __f._M_fmt, __fmt_end).failed())
+                __err |= ios_base::badbit;
+            }
+          __catch(__cxxabiv1::__forced_unwind&)
+            {
+              __os._M_setstate(ios_base::badbit);
+              __throw_exception_again;
+            }
+          __catch(...)
+            { __os._M_setstate(ios_base::badbit); }
+          if (__err)
+            __os.setstate(__err);
+        }
+      return __os;
+    }
+
+  template<typename _CharT>
+    struct _Get_time
+    {
+      std::tm*	    _M_tmb;
+      const _CharT* _M_fmt;
+    };
+
+  /**
+   *  @brief  Extended manipulator for extracting time.
+   *
+   *  This manipulator uses time_get::get to extract time.
+   *  [ext.manip]
+   *
+   *  @param __tmb  struct to extract the time data to.
+   *  @param __fmt  format string.
+   */
+  template<typename _CharT>
+    inline _Get_time<_CharT>
+    get_time(std::tm* __tmb, const _CharT* __fmt)
+    { return { __tmb, __fmt }; }
+
+  template<typename _CharT, typename _Traits>
+    basic_istream<_CharT, _Traits>&
+    operator>>(basic_istream<_CharT, _Traits>& __is, _Get_time<_CharT> __f)
+    {
+      typename basic_istream<_CharT, _Traits>::sentry __cerb(__is, false);
+      if (__cerb)
+        {
+          ios_base::iostate __err = ios_base::goodbit;
+          __try
+            {
+              typedef istreambuf_iterator<_CharT, _Traits>   _Iter;
+              typedef time_get<_CharT, _Iter>                _TimeGet;
+
+              const _CharT* const __fmt_end = __f._M_fmt +
+                _Traits::length(__f._M_fmt);
+
+              const _TimeGet& __mg = use_facet<_TimeGet>(__is.getloc());
+              __mg.get(_Iter(__is.rdbuf()), _Iter(), __is,
+                       __err, __f._M_tmb, __f._M_fmt, __fmt_end);
+            }
+          __catch(__cxxabiv1::__forced_unwind&)
+            {
+              __is._M_setstate(ios_base::badbit);
+              __throw_exception_again;
+            }
+          __catch(...)
+            { __is._M_setstate(ios_base::badbit); }
+          if (__err)
+            __is.setstate(__err);
+        }
+      return __is;
+    }
+
+#if __cplusplus >= 201402L
+
+#define __cpp_lib_quoted_string_io 201304L
+
+  /**
+   * @brief Manipulator for quoted strings.
+   * @param __string String to quote.
+   * @param __delim  Character to quote string with.
+   * @param __escape Escape character to escape itself or quote character.
+   */
+  template<typename _CharT>
+    inline auto
+    quoted(const _CharT* __string,
+	   _CharT __delim = _CharT('"'), _CharT __escape = _CharT('\\'))
+    {
+      return __detail::_Quoted_string<const _CharT*, _CharT>(__string, __delim,
+							     __escape);
+    }
+
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    inline auto
+    quoted(const basic_string<_CharT, _Traits, _Alloc>& __string,
+	   _CharT __delim = _CharT('"'), _CharT __escape = _CharT('\\'))
+    {
+      return __detail::_Quoted_string<
+	const basic_string<_CharT, _Traits, _Alloc>&, _CharT>(
+	    __string, __delim, __escape);
+    }
+
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    inline auto
+    quoted(basic_string<_CharT, _Traits, _Alloc>& __string,
+	   _CharT __delim = _CharT('"'), _CharT __escape = _CharT('\\'))
+    {
+      return __detail::_Quoted_string<
+	basic_string<_CharT, _Traits, _Alloc>&, _CharT>(
+	    __string, __delim, __escape);
+    }
+
+#if __cplusplus >= 201703L
+  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+  // 2785. quoted should work with basic_string_view
+  template<typename _CharT, typename _Traits>
+    inline auto
+    quoted(basic_string_view<_CharT, _Traits> __sv,
+	   _CharT __delim = _CharT('"'), _CharT __escape = _CharT('\\'))
+    {
+      return __detail::_Quoted_string<
+	basic_string_view<_CharT, _Traits>, _CharT>(__sv, __delim, __escape);
+    }
+#endif // C++17
+#endif // C++14
+
+#endif // __cplusplus >= 201103L
+
+  // Inhibit implicit instantiations for required instantiations,
+  // which are defined via explicit instantiations elsewhere.
+  // NB:  This syntax is a GNU extension.
+#if _GLIBCXX_EXTERN_TEMPLATE
+  extern template ostream& operator<<(ostream&, _Setfill<char>);
+  extern template ostream& operator<<(ostream&, _Setiosflags);
+  extern template ostream& operator<<(ostream&, _Resetiosflags);
+  extern template ostream& operator<<(ostream&, _Setbase);
+  extern template ostream& operator<<(ostream&, _Setprecision);
+  extern template ostream& operator<<(ostream&, _Setw);
+  extern template istream& operator>>(istream&, _Setfill<char>);
+  extern template istream& operator>>(istream&, _Setiosflags);
+  extern template istream& operator>>(istream&, _Resetiosflags);
+  extern template istream& operator>>(istream&, _Setbase);
+  extern template istream& operator>>(istream&, _Setprecision);
+  extern template istream& operator>>(istream&, _Setw);
+
+#ifdef _GLIBCXX_USE_WCHAR_T
+  extern template wostream& operator<<(wostream&, _Setfill<wchar_t>);
+  extern template wostream& operator<<(wostream&, _Setiosflags);
+  extern template wostream& operator<<(wostream&, _Resetiosflags);
+  extern template wostream& operator<<(wostream&, _Setbase);
+  extern template wostream& operator<<(wostream&, _Setprecision);
+  extern template wostream& operator<<(wostream&, _Setw);
+  extern template wistream& operator>>(wistream&, _Setfill<wchar_t>);
+  extern template wistream& operator>>(wistream&, _Setiosflags);
+  extern template wistream& operator>>(wistream&, _Resetiosflags);
+  extern template wistream& operator>>(wistream&, _Setbase);
+  extern template wistream& operator>>(wistream&, _Setprecision);
+  extern template wistream& operator>>(wistream&, _Setw);
+#endif
+#endif
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif /* _GLIBCXX_IOMANIP */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@iomanip.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@iomanip.blob
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Binary files /dev/null and b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@iomanip.blob differ
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@ios b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@ios
new file mode 100644
index 0000000000000000000000000000000000000000..50a66cd9886e262d8ccfd89c15fb7d36f9951cce
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@ios
@@ -0,0 +1,46 @@
+// Iostreams base classes -*- C++ -*-
+
+// Copyright (C) 1997-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file include/ios
+ *  This is a Standard C++ Library header.
+ */
+
+//
+// ISO C++ 14882: 27.4  Iostreams base classes
+//
+
+#ifndef _GLIBCXX_IOS
+#define _GLIBCXX_IOS 1
+
+#pragma GCC system_header
+
+#include <iosfwd>
+#include <exception> 		// For ios_base::failure
+#include <bits/char_traits.h> 	// For char_traits, streamoff, streamsize, fpos
+#include <bits/localefwd.h>	// For class locale
+#include <bits/ios_base.h>	// For ios_base declarations.
+#include <streambuf>
+#include <bits/basic_ios.h>
+
+#endif	/* _GLIBCXX_IOS */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@ios.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@ios.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@iosfwd b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@iosfwd
new file mode 100644
index 0000000000000000000000000000000000000000..ddf0c953856c797ad3909de86306b0f52891e8fb
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@iosfwd
@@ -0,0 +1,256 @@
+// <iosfwd> Forward declarations -*- C++ -*-
+
+// Copyright (C) 1997-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file include/iosfwd
+ *  This is a Standard C++ Library header.
+ */
+
+//
+// ISO C++ 14882: 27.2  Forward declarations
+//
+
+#ifndef _GLIBCXX_IOSFWD
+#define _GLIBCXX_IOSFWD 1
+
+#pragma GCC system_header
+
+#include <bits/c++config.h>
+#include <bits/stringfwd.h> 	// For string forward declarations.
+#include <bits/postypes.h>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /**
+   *  @defgroup io I/O
+   *
+   *  Nearly all of the I/O classes are parameterized on the type of
+   *  characters they read and write.  (The major exception is ios_base at
+   *  the top of the hierarchy.)  This is a change from pre-Standard
+   *  streams, which were not templates.
+   *
+   *  For ease of use and compatibility, all of the basic_* I/O-related
+   *  classes are given typedef names for both of the builtin character
+   *  widths (wide and narrow).  The typedefs are the same as the
+   *  pre-Standard names, for example:
+   *
+   *  @code
+   *     typedef basic_ifstream<char>  ifstream;
+   *  @endcode
+   *
+   *  Because properly forward-declaring these classes can be difficult, you
+   *  should not do it yourself.  Instead, include the &lt;iosfwd&gt;
+   *  header, which contains only declarations of all the I/O classes as
+   *  well as the typedefs.  Trying to forward-declare the typedefs
+   *  themselves (e.g., <code>class ostream;</code>) is not valid ISO C++.
+   *
+   *  For more specific declarations, see
+   *  https://gcc.gnu.org/onlinedocs/libstdc++/manual/io.html#std.io.objects
+   *
+   *  @{
+  */
+  class ios_base;
+
+  template<typename _CharT, typename _Traits = char_traits<_CharT> >
+    class basic_ios;
+
+  template<typename _CharT, typename _Traits = char_traits<_CharT> >
+    class basic_streambuf;
+
+  template<typename _CharT, typename _Traits = char_traits<_CharT> >
+    class basic_istream;
+
+  template<typename _CharT, typename _Traits = char_traits<_CharT> >
+    class basic_ostream;
+
+  template<typename _CharT, typename _Traits = char_traits<_CharT> >
+    class basic_iostream;
+
+
+_GLIBCXX_BEGIN_NAMESPACE_CXX11
+
+  template<typename _CharT, typename _Traits = char_traits<_CharT>,
+	    typename _Alloc = allocator<_CharT> >
+    class basic_stringbuf;
+
+  template<typename _CharT, typename _Traits = char_traits<_CharT>,
+	   typename _Alloc = allocator<_CharT> >
+    class basic_istringstream;
+
+  template<typename _CharT, typename _Traits = char_traits<_CharT>,
+	   typename _Alloc = allocator<_CharT> >
+    class basic_ostringstream;
+
+  template<typename _CharT, typename _Traits = char_traits<_CharT>,
+	   typename _Alloc = allocator<_CharT> >
+    class basic_stringstream;
+
+_GLIBCXX_END_NAMESPACE_CXX11
+
+  template<typename _CharT, typename _Traits = char_traits<_CharT> >
+    class basic_filebuf;
+
+  template<typename _CharT, typename _Traits = char_traits<_CharT> >
+    class basic_ifstream;
+
+  template<typename _CharT, typename _Traits = char_traits<_CharT> >
+    class basic_ofstream;
+
+  template<typename _CharT, typename _Traits = char_traits<_CharT> >
+    class basic_fstream;
+
+  template<typename _CharT, typename _Traits = char_traits<_CharT> >
+    class istreambuf_iterator;
+
+  template<typename _CharT, typename _Traits = char_traits<_CharT> >
+    class ostreambuf_iterator;
+
+
+  /// Base class for @c char streams.
+  typedef basic_ios<char> 		ios;
+
+  /// Base class for @c char buffers.
+  typedef basic_streambuf<char> 	streambuf;
+
+  /// Base class for @c char input streams.
+  typedef basic_istream<char> 		istream;
+
+  /// Base class for @c char output streams.
+  typedef basic_ostream<char> 		ostream;
+
+  /// Base class for @c char mixed input and output streams.
+  typedef basic_iostream<char> 		iostream;
+
+  /// Class for @c char memory buffers.
+  typedef basic_stringbuf<char> 	stringbuf;
+
+  /// Class for @c char input memory streams.
+  typedef basic_istringstream<char> 	istringstream;
+
+  /// Class for @c char output memory streams.
+  typedef basic_ostringstream<char> 	ostringstream;
+
+  /// Class for @c char mixed input and output memory streams.
+  typedef basic_stringstream<char> 	stringstream;
+
+  /// Class for @c char file buffers.
+  typedef basic_filebuf<char> 		filebuf;
+
+  /// Class for @c char input file streams.
+  typedef basic_ifstream<char> 		ifstream;
+
+  /// Class for @c char output file streams.
+  typedef basic_ofstream<char> 		ofstream;
+
+  /// Class for @c char mixed input and output file streams.
+  typedef basic_fstream<char> 		fstream;
+
+#ifdef _GLIBCXX_USE_WCHAR_T
+  /// Base class for @c wchar_t streams.
+  typedef basic_ios<wchar_t> 		wios;
+
+  /// Base class for @c wchar_t buffers.
+  typedef basic_streambuf<wchar_t> 	wstreambuf;
+
+  /// Base class for @c wchar_t input streams.
+  typedef basic_istream<wchar_t> 	wistream;
+
+  /// Base class for @c wchar_t output streams.
+  typedef basic_ostream<wchar_t> 	wostream;
+
+  /// Base class for @c wchar_t mixed input and output streams.
+  typedef basic_iostream<wchar_t> 	wiostream;
+
+  /// Class for @c wchar_t memory buffers.
+  typedef basic_stringbuf<wchar_t> 	wstringbuf;
+
+  /// Class for @c wchar_t input memory streams.
+  typedef basic_istringstream<wchar_t> 	wistringstream;
+
+  /// Class for @c wchar_t output memory streams.
+  typedef basic_ostringstream<wchar_t> 	wostringstream;
+
+  /// Class for @c wchar_t mixed input and output memory streams.
+  typedef basic_stringstream<wchar_t> 	wstringstream;
+
+  /// Class for @c wchar_t file buffers.
+  typedef basic_filebuf<wchar_t> 	wfilebuf;
+
+  /// Class for @c wchar_t input file streams.
+  typedef basic_ifstream<wchar_t> 	wifstream;
+
+  /// Class for @c wchar_t output file streams.
+  typedef basic_ofstream<wchar_t> 	wofstream;
+
+  /// Class for @c wchar_t mixed input and output file streams.
+  typedef basic_fstream<wchar_t> 	wfstream;
+#endif
+
+#if __cplusplus >= 202002L && _GLIBCXX_USE_CXX11_ABI
+  template<typename _CharT, typename _Traits = char_traits<_CharT>,
+           typename _Allocator = allocator<_CharT>>
+    class basic_syncbuf;
+  template<typename _CharT, typename _Traits = char_traits<_CharT>,
+           typename _Allocator = allocator<_CharT>>
+    class basic_osyncstream;
+
+  using syncbuf = basic_syncbuf<char>;
+  using osyncstream = basic_osyncstream<char>;
+
+#ifdef _GLIBCXX_USE_WCHAR_T
+  using wsyncbuf = basic_syncbuf<wchar_t>;
+  using wosyncstream = basic_osyncstream<wchar_t>;
+#endif
+#endif // C++20 && CXX11_ABI
+
+#if __cplusplus > 202002L
+  template<typename _CharT, typename _Traits = char_traits<_CharT>>
+    class basic_spanbuf;
+  template<typename _CharT, typename _Traits = char_traits<_CharT>>
+    class basic_ispanstream;
+  template<typename _CharT, typename _Traits = char_traits<_CharT>>
+    class basic_ospanstream;
+  template<typename _CharT, typename _Traits = char_traits<_CharT>>
+    class basic_spanstream;
+
+  using spanbuf     = basic_spanbuf<char>;
+  using ispanstream = basic_ispanstream<char>;
+  using ospanstream = basic_ospanstream<char>;
+  using spanstream  = basic_spanstream<char>;
+
+#ifdef _GLIBCXX_USE_WCHAR_T
+  using wspanbuf     = basic_spanbuf<wchar_t>;
+  using wispanstream = basic_ispanstream<wchar_t>;
+  using wospanstream = basic_ospanstream<wchar_t>;
+  using wspanstream  = basic_spanstream<wchar_t>;
+#endif
+#endif // C++23
+
+  /** @}  */
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif /* _GLIBCXX_IOSFWD */
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@iostream
@@ -0,0 +1,79 @@
+// Standard iostream objects -*- C++ -*-
+
+// Copyright (C) 1997-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file include/iostream
+ *  This is a Standard C++ Library header.
+ */
+
+//
+// ISO C++ 14882: 27.3  Standard iostream objects
+//
+
+#ifndef _GLIBCXX_IOSTREAM
+#define _GLIBCXX_IOSTREAM 1
+
+#pragma GCC system_header
+
+#include <bits/c++config.h>
+#include <ostream>
+#include <istream>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /**
+   *  @name Standard Stream Objects
+   *
+   *  The &lt;iostream&gt; header declares the eight <em>standard stream
+   *  objects</em>.  For other declarations, see
+   *  http://gcc.gnu.org/onlinedocs/libstdc++/manual/io.html
+   *  and the @link iosfwd I/O forward declarations @endlink
+   *
+   *  They are required by default to cooperate with the global C
+   *  library's @c FILE streams, and to be available during program
+   *  startup and termination. For more information, see the section of the
+   *  manual linked to above.
+  */
+  ///@{
+  extern istream cin;		/// Linked to standard input
+  extern ostream cout;		/// Linked to standard output
+  extern ostream cerr;		/// Linked to standard error (unbuffered)
+  extern ostream clog;		/// Linked to standard error (buffered)
+
+#ifdef _GLIBCXX_USE_WCHAR_T
+  extern wistream wcin;		/// Linked to standard input
+  extern wostream wcout;	/// Linked to standard output
+  extern wostream wcerr;	/// Linked to standard error (unbuffered)
+  extern wostream wclog;	/// Linked to standard error (buffered)
+#endif
+  ///@}
+
+  // For construction of filebuffers for cout, cin, cerr, clog et. al.
+  static ios_base::Init __ioinit;
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif /* _GLIBCXX_IOSTREAM */
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@istream
@@ -0,0 +1,1018 @@
+// Input streams -*- C++ -*-
+
+// Copyright (C) 1997-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+//
+// ISO C++ 14882: 27.6.1  Input streams
+//
+
+/** @file include/istream
+ *  This is a Standard C++ Library header.
+ */
+
+#ifndef _GLIBCXX_ISTREAM
+#define _GLIBCXX_ISTREAM 1
+
+#pragma GCC system_header
+
+#include <ios>
+#include <ostream>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /**
+   *  @brief  Template class basic_istream.
+   *  @ingroup io
+   *
+   *  @tparam _CharT  Type of character stream.
+   *  @tparam _Traits  Traits for character type, defaults to
+   *                   char_traits<_CharT>.
+   *
+   *  This is the base class for all input streams.  It provides text
+   *  formatting of all builtin types, and communicates with any class
+   *  derived from basic_streambuf to do the actual input.
+  */
+  template<typename _CharT, typename _Traits>
+    class basic_istream : virtual public basic_ios<_CharT, _Traits>
+    {
+    public:
+      // Types (inherited from basic_ios (27.4.4)):
+      typedef _CharT			 		char_type;
+      typedef typename _Traits::int_type 		int_type;
+      typedef typename _Traits::pos_type 		pos_type;
+      typedef typename _Traits::off_type 		off_type;
+      typedef _Traits			 		traits_type;
+
+      // Non-standard Types:
+      typedef basic_streambuf<_CharT, _Traits> 		__streambuf_type;
+      typedef basic_ios<_CharT, _Traits>		__ios_type;
+      typedef basic_istream<_CharT, _Traits>		__istream_type;
+      typedef num_get<_CharT, istreambuf_iterator<_CharT, _Traits> >
+ 							__num_get_type;
+      typedef ctype<_CharT>	      			__ctype_type;
+
+    protected:
+      // Data Members:
+      /**
+       *  The number of characters extracted in the previous unformatted
+       *  function; see gcount().
+      */
+      streamsize 		_M_gcount;
+
+    public:
+      /**
+       *  @brief  Base constructor.
+       *
+       *  This ctor is almost never called by the user directly, rather from
+       *  derived classes' initialization lists, which pass a pointer to
+       *  their own stream buffer.
+      */
+      explicit
+      basic_istream(__streambuf_type* __sb)
+      : _M_gcount(streamsize(0))
+      { this->init(__sb); }
+
+      /**
+       *  @brief  Base destructor.
+       *
+       *  This does very little apart from providing a virtual base dtor.
+      */
+      virtual
+      ~basic_istream()
+      { _M_gcount = streamsize(0); }
+
+      /// Safe prefix/suffix operations.
+      class sentry;
+      friend class sentry;
+
+      ///@{
+      /**
+       *  @brief  Interface for manipulators.
+       *
+       *  Manipulators such as @c std::ws and @c std::dec use these
+       *  functions in constructs like
+       *  <code>std::cin >> std::ws</code>.
+       *  For more information, see the iomanip header.
+      */
+      __istream_type&
+      operator>>(__istream_type& (*__pf)(__istream_type&))
+      { return __pf(*this); }
+
+      __istream_type&
+      operator>>(__ios_type& (*__pf)(__ios_type&))
+      {
+	__pf(*this);
+	return *this;
+      }
+
+      __istream_type&
+      operator>>(ios_base& (*__pf)(ios_base&))
+      {
+	__pf(*this);
+	return *this;
+      }
+      ///@}
+
+      ///@{
+      /**
+       *  @name Extractors
+       *
+       *  All the @c operator>> functions (aka <em>formatted input
+       *  functions</em>) have some common behavior.  Each starts by
+       *  constructing a temporary object of type std::basic_istream::sentry
+       *  with the second argument (noskipws) set to false.  This has several
+       *  effects, concluding with the setting of a status flag; see the
+       *  sentry documentation for more.
+       *
+       *  If the sentry status is good, the function tries to extract
+       *  whatever data is appropriate for the type of the argument.
+       *
+       *  If an exception is thrown during extraction, ios_base::badbit
+       *  will be turned on in the stream's error state (without causing an
+       *  ios_base::failure to be thrown) and the original exception will
+       *  be rethrown if badbit is set in the exceptions mask.
+      */
+
+      ///@{
+      /**
+       *  @brief  Integer arithmetic extractors
+       *  @param  __n A variable of builtin integral type.
+       *  @return  @c *this if successful
+       *
+       *  These functions use the stream's current locale (specifically, the
+       *  @c num_get facet) to parse the input data.
+      */
+      __istream_type&
+      operator>>(bool& __n)
+      { return _M_extract(__n); }
+
+      __istream_type&
+      operator>>(short& __n);
+
+      __istream_type&
+      operator>>(unsigned short& __n)
+      { return _M_extract(__n); }
+
+      __istream_type&
+      operator>>(int& __n);
+
+      __istream_type&
+      operator>>(unsigned int& __n)
+      { return _M_extract(__n); }
+
+      __istream_type&
+      operator>>(long& __n)
+      { return _M_extract(__n); }
+
+      __istream_type&
+      operator>>(unsigned long& __n)
+      { return _M_extract(__n); }
+
+#ifdef _GLIBCXX_USE_LONG_LONG
+      __istream_type&
+      operator>>(long long& __n)
+      { return _M_extract(__n); }
+
+      __istream_type&
+      operator>>(unsigned long long& __n)
+      { return _M_extract(__n); }
+#endif
+      ///@}
+
+      ///@{
+      /**
+       *  @brief  Floating point arithmetic extractors
+       *  @param  __f A variable of builtin floating point type.
+       *  @return  @c *this if successful
+       *
+       *  These functions use the stream's current locale (specifically, the
+       *  @c num_get facet) to parse the input data.
+      */
+      __istream_type&
+      operator>>(float& __f)
+      { return _M_extract(__f); }
+
+      __istream_type&
+      operator>>(double& __f)
+      { return _M_extract(__f); }
+
+      __istream_type&
+      operator>>(long double& __f)
+      { return _M_extract(__f); }
+      ///@}
+
+      /**
+       *  @brief  Basic arithmetic extractors
+       *  @param  __p A variable of pointer type.
+       *  @return  @c *this if successful
+       *
+       *  These functions use the stream's current locale (specifically, the
+       *  @c num_get facet) to parse the input data.
+      */
+      __istream_type&
+      operator>>(void*& __p)
+      { return _M_extract(__p); }
+
+      /**
+       *  @brief  Extracting into another streambuf.
+       *  @param  __sb  A pointer to a streambuf
+       *
+       *  This function behaves like one of the basic arithmetic extractors,
+       *  in that it also constructs a sentry object and has the same error
+       *  handling behavior.
+       *
+       *  If @p __sb is NULL, the stream will set failbit in its error state.
+       *
+       *  Characters are extracted from this stream and inserted into the
+       *  @p __sb streambuf until one of the following occurs:
+       *
+       *  - the input stream reaches end-of-file,
+       *  - insertion into the output buffer fails (in this case, the
+       *    character that would have been inserted is not extracted), or
+       *  - an exception occurs (and in this case is caught)
+       *
+       *  If the function inserts no characters, failbit is set.
+      */
+      __istream_type&
+      operator>>(__streambuf_type* __sb);
+      ///@}
+
+      // [27.6.1.3] unformatted input
+      /**
+       *  @brief  Character counting
+       *  @return  The number of characters extracted by the previous
+       *           unformatted input function dispatched for this stream.
+      */
+      streamsize
+      gcount() const
+      { return _M_gcount; }
+
+      ///@{
+      /**
+       *  @name Unformatted Input Functions
+       *
+       *  All the unformatted input functions have some common behavior.
+       *  Each starts by constructing a temporary object of type
+       *  std::basic_istream::sentry with the second argument (noskipws)
+       *  set to true.  This has several effects, concluding with the
+       *  setting of a status flag; see the sentry documentation for more.
+       *
+       *  If the sentry status is good, the function tries to extract
+       *  whatever data is appropriate for the type of the argument.
+       *
+       *  The number of characters extracted is stored for later retrieval
+       *  by gcount().
+       *
+       *  If an exception is thrown during extraction, ios_base::badbit
+       *  will be turned on in the stream's error state (without causing an
+       *  ios_base::failure to be thrown) and the original exception will
+       *  be rethrown if badbit is set in the exceptions mask.
+      */
+
+      /**
+       *  @brief  Simple extraction.
+       *  @return  A character, or eof().
+       *
+       *  Tries to extract a character.  If none are available, sets failbit
+       *  and returns traits::eof().
+      */
+      int_type
+      get();
+
+      /**
+       *  @brief  Simple extraction.
+       *  @param  __c  The character in which to store data.
+       *  @return  *this
+       *
+       *  Tries to extract a character and store it in @a __c.  If none are
+       *  available, sets failbit and returns traits::eof().
+       *
+       *  @note  This function is not overloaded on signed char and
+       *         unsigned char.
+      */
+      __istream_type&
+      get(char_type& __c);
+
+      /**
+       *  @brief  Simple multiple-character extraction.
+       *  @param  __s  Pointer to an array.
+       *  @param  __n  Maximum number of characters to store in @a __s.
+       *  @param  __delim  A "stop" character.
+       *  @return  *this
+       *
+       *  Characters are extracted and stored into @a __s until one of the
+       *  following happens:
+       *
+       *  - @c __n-1 characters are stored
+       *  - the input sequence reaches EOF
+       *  - the next character equals @a __delim, in which case the character
+       *    is not extracted
+       *
+       * If no characters are stored, failbit is set in the stream's error
+       * state.
+       *
+       * In any case, a null character is stored into the next location in
+       * the array.
+       *
+       *  @note  This function is not overloaded on signed char and
+       *         unsigned char.
+      */
+      __istream_type&
+      get(char_type* __s, streamsize __n, char_type __delim);
+
+      /**
+       *  @brief  Simple multiple-character extraction.
+       *  @param  __s  Pointer to an array.
+       *  @param  __n  Maximum number of characters to store in @a s.
+       *  @return  *this
+       *
+       *  Returns @c get(__s,__n,widen(&apos;\\n&apos;)).
+      */
+      __istream_type&
+      get(char_type* __s, streamsize __n)
+      { return this->get(__s, __n, this->widen('\n')); }
+
+      /**
+       *  @brief  Extraction into another streambuf.
+       *  @param  __sb  A streambuf in which to store data.
+       *  @param  __delim  A "stop" character.
+       *  @return  *this
+       *
+       *  Characters are extracted and inserted into @a __sb until one of the
+       *  following happens:
+       *
+       *  - the input sequence reaches EOF
+       *  - insertion into the output buffer fails (in this case, the
+       *    character that would have been inserted is not extracted)
+       *  - the next character equals @a __delim (in this case, the character
+       *    is not extracted)
+       *  - an exception occurs (and in this case is caught)
+       *
+       * If no characters are stored, failbit is set in the stream's error
+       * state.
+      */
+      __istream_type&
+      get(__streambuf_type& __sb, char_type __delim);
+
+      /**
+       *  @brief  Extraction into another streambuf.
+       *  @param  __sb  A streambuf in which to store data.
+       *  @return  *this
+       *
+       *  Returns @c get(__sb,widen(&apos;\\n&apos;)).
+      */
+      __istream_type&
+      get(__streambuf_type& __sb)
+      { return this->get(__sb, this->widen('\n')); }
+
+      /**
+       *  @brief  String extraction.
+       *  @param  __s  A character array in which to store the data.
+       *  @param  __n  Maximum number of characters to extract.
+       *  @param  __delim  A "stop" character.
+       *  @return  *this
+       *
+       *  Extracts and stores characters into @a __s until one of the
+       *  following happens.  Note that these criteria are required to be
+       *  tested in the order listed here, to allow an input line to exactly
+       *  fill the @a __s array without setting failbit.
+       *
+       *  -# the input sequence reaches end-of-file, in which case eofbit
+       *     is set in the stream error state
+       *  -# the next character equals @c __delim, in which case the character
+       *     is extracted (and therefore counted in @c gcount()) but not stored
+       *  -# @c __n-1 characters are stored, in which case failbit is set
+       *     in the stream error state
+       *
+       *  If no characters are extracted, failbit is set.  (An empty line of
+       *  input should therefore not cause failbit to be set.)
+       *
+       *  In any case, a null character is stored in the next location in
+       *  the array.
+      */
+      __istream_type&
+      getline(char_type* __s, streamsize __n, char_type __delim);
+
+      /**
+       *  @brief  String extraction.
+       *  @param  __s  A character array in which to store the data.
+       *  @param  __n  Maximum number of characters to extract.
+       *  @return  *this
+       *
+       *  Returns @c getline(__s,__n,widen(&apos;\\n&apos;)).
+      */
+      __istream_type&
+      getline(char_type* __s, streamsize __n)
+      { return this->getline(__s, __n, this->widen('\n')); }
+
+      /**
+       *  @brief  Discarding characters
+       *  @param  __n  Number of characters to discard.
+       *  @param  __delim  A "stop" character.
+       *  @return  *this
+       *
+       *  Extracts characters and throws them away until one of the
+       *  following happens:
+       *  - if @a __n @c != @c std::numeric_limits<int>::max(), @a __n
+       *    characters are extracted
+       *  - the input sequence reaches end-of-file
+       *  - the next character equals @a __delim (in this case, the character
+       *    is extracted); note that this condition will never occur if
+       *    @a __delim equals @c traits::eof().
+       *
+       *  NB: Provide three overloads, instead of the single function
+       *  (with defaults) mandated by the Standard: this leads to a
+       *  better performing implementation, while still conforming to
+       *  the Standard.
+      */
+      __istream_type&
+      ignore(streamsize __n, int_type __delim);
+
+      __istream_type&
+      ignore(streamsize __n);
+
+      __istream_type&
+      ignore();
+
+      /**
+       *  @brief  Looking ahead in the stream
+       *  @return  The next character, or eof().
+       *
+       *  If, after constructing the sentry object, @c good() is false,
+       *  returns @c traits::eof().  Otherwise reads but does not extract
+       *  the next input character.
+      */
+      int_type
+      peek();
+
+      /**
+       *  @brief  Extraction without delimiters.
+       *  @param  __s  A character array.
+       *  @param  __n  Maximum number of characters to store.
+       *  @return  *this
+       *
+       *  If the stream state is @c good(), extracts characters and stores
+       *  them into @a __s until one of the following happens:
+       *  - @a __n characters are stored
+       *  - the input sequence reaches end-of-file, in which case the error
+       *    state is set to @c failbit|eofbit.
+       *
+       *  @note  This function is not overloaded on signed char and
+       *         unsigned char.
+      */
+      __istream_type&
+      read(char_type* __s, streamsize __n);
+
+      /**
+       *  @brief  Extraction until the buffer is exhausted, but no more.
+       *  @param  __s  A character array.
+       *  @param  __n  Maximum number of characters to store.
+       *  @return  The number of characters extracted.
+       *
+       *  Extracts characters and stores them into @a __s depending on the
+       *  number of characters remaining in the streambuf's buffer,
+       *  @c rdbuf()->in_avail(), called @c A here:
+       *  - if @c A @c == @c -1, sets eofbit and extracts no characters
+       *  - if @c A @c == @c 0, extracts no characters
+       *  - if @c A @c > @c 0, extracts @c min(A,n)
+       *
+       *  The goal is to empty the current buffer, and to not request any
+       *  more from the external input sequence controlled by the streambuf.
+      */
+      streamsize
+      readsome(char_type* __s, streamsize __n);
+
+      /**
+       *  @brief  Unextracting a single character.
+       *  @param  __c  The character to push back into the input stream.
+       *  @return  *this
+       *
+       *  If @c rdbuf() is not null, calls @c rdbuf()->sputbackc(c).
+       *
+       *  If @c rdbuf() is null or if @c sputbackc() fails, sets badbit in
+       *  the error state.
+       *
+       *  @note  This function first clears eofbit.  Since no characters
+       *         are extracted, the next call to @c gcount() will return 0,
+       *         as required by DR 60.
+      */
+      __istream_type&
+      putback(char_type __c);
+
+      /**
+       *  @brief  Unextracting the previous character.
+       *  @return  *this
+       *
+       *  If @c rdbuf() is not null, calls @c rdbuf()->sungetc(c).
+       *
+       *  If @c rdbuf() is null or if @c sungetc() fails, sets badbit in
+       *  the error state.
+       *
+       *  @note  This function first clears eofbit.  Since no characters
+       *         are extracted, the next call to @c gcount() will return 0,
+       *         as required by DR 60.
+      */
+      __istream_type&
+      unget();
+
+      /**
+       *  @brief  Synchronizing the stream buffer.
+       *  @return  0 on success, -1 on failure
+       *
+       *  If @c rdbuf() is a null pointer, returns -1.
+       *
+       *  Otherwise, calls @c rdbuf()->pubsync(), and if that returns -1,
+       *  sets badbit and returns -1.
+       *
+       *  Otherwise, returns 0.
+       *
+       *  @note  This function does not count the number of characters
+       *         extracted, if any, and therefore does not affect the next
+       *         call to @c gcount().
+      */
+      int
+      sync();
+
+      /**
+       *  @brief  Getting the current read position.
+       *  @return  A file position object.
+       *
+       *  If @c fail() is not false, returns @c pos_type(-1) to indicate
+       *  failure.  Otherwise returns @c rdbuf()->pubseekoff(0,cur,in).
+       *
+       *  @note  This function does not count the number of characters
+       *         extracted, if any, and therefore does not affect the next
+       *         call to @c gcount().  At variance with putback, unget and
+       *         seekg, eofbit is not cleared first.
+      */
+      pos_type
+      tellg();
+
+      /**
+       *  @brief  Changing the current read position.
+       *  @param  __pos  A file position object.
+       *  @return  *this
+       *
+       *  If @c fail() is not true, calls @c rdbuf()->pubseekpos(__pos).  If
+       *  that function fails, sets failbit.
+       *
+       *  @note  This function first clears eofbit.  It does not count the
+       *         number of characters extracted, if any, and therefore does
+       *         not affect the next call to @c gcount().
+      */
+      __istream_type&
+      seekg(pos_type);
+
+      /**
+       *  @brief  Changing the current read position.
+       *  @param  __off  A file offset object.
+       *  @param  __dir  The direction in which to seek.
+       *  @return  *this
+       *
+       *  If @c fail() is not true, calls @c rdbuf()->pubseekoff(__off,__dir).
+       *  If that function fails, sets failbit.
+       *
+       *  @note  This function first clears eofbit.  It does not count the
+       *         number of characters extracted, if any, and therefore does
+       *         not affect the next call to @c gcount().
+      */
+      __istream_type&
+      seekg(off_type, ios_base::seekdir);
+      ///@}
+
+    protected:
+      basic_istream()
+      : _M_gcount(streamsize(0))
+      { this->init(0); }
+
+#if __cplusplus >= 201103L
+      basic_istream(const basic_istream&) = delete;
+
+      basic_istream(basic_istream&& __rhs)
+      : __ios_type(), _M_gcount(__rhs._M_gcount)
+      {
+	__ios_type::move(__rhs);
+	__rhs._M_gcount = 0;
+      }
+
+      // 27.7.3.3 Assign/swap
+
+      basic_istream& operator=(const basic_istream&) = delete;
+
+      basic_istream&
+      operator=(basic_istream&& __rhs)
+      {
+	swap(__rhs);
+	return *this;
+      }
+
+      void
+      swap(basic_istream& __rhs)
+      {
+	__ios_type::swap(__rhs);
+	std::swap(_M_gcount, __rhs._M_gcount);
+      }
+#endif
+
+      template<typename _ValueT>
+	__istream_type&
+	_M_extract(_ValueT& __v);
+    };
+
+  /// Explicit specialization declarations, defined in src/istream.cc.
+  template<>
+    basic_istream<char>&
+    basic_istream<char>::
+    getline(char_type* __s, streamsize __n, char_type __delim);
+
+  template<>
+    basic_istream<char>&
+    basic_istream<char>::
+    ignore(streamsize __n);
+
+  template<>
+    basic_istream<char>&
+    basic_istream<char>::
+    ignore(streamsize __n, int_type __delim);
+
+#ifdef _GLIBCXX_USE_WCHAR_T
+  template<>
+    basic_istream<wchar_t>&
+    basic_istream<wchar_t>::
+    getline(char_type* __s, streamsize __n, char_type __delim);
+
+  template<>
+    basic_istream<wchar_t>&
+    basic_istream<wchar_t>::
+    ignore(streamsize __n);
+
+  template<>
+    basic_istream<wchar_t>&
+    basic_istream<wchar_t>::
+    ignore(streamsize __n, int_type __delim);
+#endif
+
+  /**
+   *  @brief  Performs setup work for input streams.
+   *
+   *  Objects of this class are created before all of the standard
+   *  extractors are run.  It is responsible for <em>exception-safe
+   *  prefix and suffix operations,</em> although only prefix actions
+   *  are currently required by the standard.
+  */
+  template<typename _CharT, typename _Traits>
+    class basic_istream<_CharT, _Traits>::sentry
+    {
+      // Data Members.
+      bool _M_ok;
+
+    public:
+      /// Easy access to dependent types.
+      typedef _Traits 					traits_type;
+      typedef basic_streambuf<_CharT, _Traits> 		__streambuf_type;
+      typedef basic_istream<_CharT, _Traits> 		__istream_type;
+      typedef typename __istream_type::__ctype_type 	__ctype_type;
+      typedef typename _Traits::int_type		__int_type;
+
+      /**
+       *  @brief  The constructor performs all the work.
+       *  @param  __is  The input stream to guard.
+       *  @param  __noskipws  Whether to consume whitespace or not.
+       *
+       *  If the stream state is good (@a __is.good() is true), then the
+       *  following actions are performed, otherwise the sentry state
+       *  is false (<em>not okay</em>) and failbit is set in the
+       *  stream state.
+       *
+       *  The sentry's preparatory actions are:
+       *
+       *  -# if the stream is tied to an output stream, @c is.tie()->flush()
+       *     is called to synchronize the output sequence
+       *  -# if @a __noskipws is false, and @c ios_base::skipws is set in
+       *     @c is.flags(), the sentry extracts and discards whitespace
+       *     characters from the stream.  The currently imbued locale is
+       *     used to determine whether each character is whitespace.
+       *
+       *  If the stream state is still good, then the sentry state becomes
+       *  true (@a okay).
+      */
+      explicit
+      sentry(basic_istream<_CharT, _Traits>& __is, bool __noskipws = false);
+
+      /**
+       *  @brief  Quick status checking.
+       *  @return  The sentry state.
+       *
+       *  For ease of use, sentries may be converted to booleans.  The
+       *  return value is that of the sentry state (true == okay).
+      */
+#if __cplusplus >= 201103L
+      explicit
+#endif
+      operator bool() const
+      { return _M_ok; }
+    };
+
+  ///@{
+  /**
+   *  @brief  Character extractors
+   *  @param  __in  An input stream.
+   *  @param  __c  A character reference.
+   *  @return  in
+   *
+   *  Behaves like one of the formatted arithmetic extractors described in
+   *  std::basic_istream.  After constructing a sentry object with good
+   *  status, this function extracts a character (if one is available) and
+   *  stores it in @a __c.  Otherwise, sets failbit in the input stream.
+  */
+  template<typename _CharT, typename _Traits>
+    basic_istream<_CharT, _Traits>&
+    operator>>(basic_istream<_CharT, _Traits>& __in, _CharT& __c);
+
+  template<class _Traits>
+    inline basic_istream<char, _Traits>&
+    operator>>(basic_istream<char, _Traits>& __in, unsigned char& __c)
+    { return (__in >> reinterpret_cast<char&>(__c)); }
+
+  template<class _Traits>
+    inline basic_istream<char, _Traits>&
+    operator>>(basic_istream<char, _Traits>& __in, signed char& __c)
+    { return (__in >> reinterpret_cast<char&>(__c)); }
+  ///@}
+
+
+  template<typename _CharT, typename _Traits>
+    void
+    __istream_extract(basic_istream<_CharT, _Traits>&, _CharT*, streamsize);
+
+  void __istream_extract(istream&, char*, streamsize);
+
+  ///@{
+  /**
+   *  @brief  Character string extractors
+   *  @param  __in  An input stream.
+   *  @param  __s  A character array (or a pointer to an array before C++20).
+   *  @return  __in
+   *
+   *  Behaves like one of the formatted arithmetic extractors described in
+   *  `std::basic_istream`.  After constructing a sentry object with good
+   *  status, this function extracts up to `n` characters and stores them
+   *  into the array `__s`.  `n` is defined as:
+   *
+   *  - if `width()` is greater than zero, `n` is `min(width(), n)`
+   *  - otherwise `n` is the number of elements of the array
+   *  - (before C++20 the pointer is assumed to point to an array of
+   *    the largest possible size for an array of `char_type`).
+   *
+   *  Characters are extracted and stored until one of the following happens:
+   *  - `n - 1` characters are stored
+   *  - EOF is reached
+   *  - the next character is whitespace according to the current locale
+   *
+   *  `width(0)` is then called for the input stream.
+   *
+   *  If no characters are extracted, sets failbit.
+  */
+
+#if __cplusplus <= 201703L
+  template<typename _CharT, typename _Traits>
+    __attribute__((__nonnull__(2), __access__(__write_only__, 2)))
+    inline basic_istream<_CharT, _Traits>&
+    operator>>(basic_istream<_CharT, _Traits>& __in, _CharT* __s)
+    {
+#ifdef __OPTIMIZE__
+      // Function inlining might make the buffer size known, allowing us to
+      // prevent overflow.
+      size_t __n = __builtin_object_size(__s, 0);
+      if (__n < sizeof(_CharT))
+	{
+	  // There is not even space for the required null terminator.
+	  __glibcxx_assert(__n >= sizeof(_CharT));
+	  // No point calling __istream_extract, but still need to reset width.
+	  __in.width(0);
+	  __in.setstate(ios_base::failbit);
+	}
+      else if (__n != (size_t)-1)
+	{
+	  __n /= sizeof(_CharT);
+	  streamsize __w = __in.width();
+	  std::__istream_extract(__in, __s, __n);
+	  if (__in.good() && (__w <= 0 || __n < __w))
+	    {
+	      // Stopped extracting early to avoid overflowing the buffer,
+	      // but might have stopped anyway (and set eofbit) if at EOF.
+	      const typename _Traits::int_type __c = __in.rdbuf()->sgetc();
+	      const bool __eof = _Traits::eq_int_type(__c, _Traits::eof());
+	      if (__builtin_expect(__eof, true)) // Assume EOF, not overflow.
+		__in.setstate(ios_base::eofbit);
+	    }
+	}
+      else
+#endif // __OPTIMIZE
+	{
+	  // Buffer size is unknown, have to assume it's huge.
+	  streamsize __n = __gnu_cxx::__numeric_traits<streamsize>::__max;
+	  __n /= sizeof(_CharT);
+	  std::__istream_extract(__in, __s, __n);
+	}
+      return __in;
+    }
+
+  template<class _Traits>
+    __attribute__((__nonnull__(2), __access__(__write_only__, 2)))
+    inline basic_istream<char, _Traits>&
+    operator>>(basic_istream<char, _Traits>& __in, unsigned char* __s)
+    { return __in >> reinterpret_cast<char*>(__s); }
+
+  template<class _Traits>
+    __attribute__((__nonnull__(2), __access__(__write_only__, 2)))
+    inline basic_istream<char, _Traits>&
+    operator>>(basic_istream<char, _Traits>& __in, signed char* __s)
+    { return __in >> reinterpret_cast<char*>(__s); }
+#else
+  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+  // 2499. operator>>(istream&, char*) makes it hard to avoid buffer overflows
+  template<typename _CharT, typename _Traits, size_t _Num>
+    inline basic_istream<_CharT, _Traits>&
+    operator>>(basic_istream<_CharT, _Traits>& __in, _CharT (&__s)[_Num])
+    {
+      static_assert(_Num <= __gnu_cxx::__numeric_traits<streamsize>::__max);
+      std::__istream_extract(__in, __s, _Num);
+      return __in;
+    }
+
+  template<class _Traits, size_t _Num>
+    inline basic_istream<char, _Traits>&
+    operator>>(basic_istream<char, _Traits>& __in, unsigned char (&__s)[_Num])
+    { return __in >> reinterpret_cast<char(&)[_Num]>(__s); }
+
+  template<class _Traits, size_t _Num>
+    inline basic_istream<char, _Traits>&
+    operator>>(basic_istream<char, _Traits>& __in, signed char (&__s)[_Num])
+    { return __in >> reinterpret_cast<char(&)[_Num]>(__s); }
+#endif
+  ///@}
+
+  /**
+   *  @brief  Template class basic_iostream
+   *  @ingroup io
+   *
+   *  @tparam _CharT  Type of character stream.
+   *  @tparam _Traits  Traits for character type, defaults to
+   *                   char_traits<_CharT>.
+   *
+   *  This class multiply inherits from the input and output stream classes
+   *  simply to provide a single interface.
+  */
+  template<typename _CharT, typename _Traits>
+    class basic_iostream
+    : public basic_istream<_CharT, _Traits>,
+      public basic_ostream<_CharT, _Traits>
+    {
+    public:
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 271. basic_iostream missing typedefs
+      // Types (inherited):
+      typedef _CharT			 		char_type;
+      typedef typename _Traits::int_type 		int_type;
+      typedef typename _Traits::pos_type 		pos_type;
+      typedef typename _Traits::off_type 		off_type;
+      typedef _Traits			 		traits_type;
+
+      // Non-standard Types:
+      typedef basic_istream<_CharT, _Traits>		__istream_type;
+      typedef basic_ostream<_CharT, _Traits>		__ostream_type;
+
+      /**
+       *  @brief  Constructor does nothing.
+       *
+       *  Both of the parent classes are initialized with the same
+       *  streambuf pointer passed to this constructor.
+      */
+      explicit
+      basic_iostream(basic_streambuf<_CharT, _Traits>* __sb)
+      : __istream_type(__sb), __ostream_type(__sb) { }
+
+      /**
+       *  @brief  Destructor does nothing.
+      */
+      virtual
+      ~basic_iostream() { }
+
+    protected:
+      basic_iostream()
+      : __istream_type(), __ostream_type() { }
+
+#if __cplusplus >= 201103L
+      basic_iostream(const basic_iostream&) = delete;
+
+      basic_iostream(basic_iostream&& __rhs)
+      : __istream_type(std::move(__rhs)), __ostream_type(*this)
+      { }
+
+      // 27.7.3.3 Assign/swap
+
+      basic_iostream& operator=(const basic_iostream&) = delete;
+
+      basic_iostream&
+      operator=(basic_iostream&& __rhs)
+      {
+	swap(__rhs);
+	return *this;
+      }
+
+      void
+      swap(basic_iostream& __rhs)
+      { __istream_type::swap(__rhs); }
+#endif
+    };
+
+  /**
+   *  @brief  Quick and easy way to eat whitespace
+   *
+   *  This manipulator extracts whitespace characters, stopping when the
+   *  next character is non-whitespace, or when the input sequence is empty.
+   *  If the sequence is empty, @c eofbit is set in the stream, but not
+   *  @c failbit.
+   *
+   *  The current locale is used to distinguish whitespace characters.
+   *
+   *  Example:
+   *  @code
+   *     MyClass   mc;
+   *
+   *     std::cin >> std::ws >> mc;
+   *  @endcode
+   *  will skip leading whitespace before calling operator>> on cin and your
+   *  object.  Note that the same effect can be achieved by creating a
+   *  std::basic_istream::sentry inside your definition of operator>>.
+  */
+  template<typename _CharT, typename _Traits>
+    basic_istream<_CharT, _Traits>&
+    ws(basic_istream<_CharT, _Traits>& __is);
+
+#if __cplusplus >= 201103L
+  // C++11 27.7.2.6 Rvalue stream extraction [istream.rvalue]
+  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+  // 2328. Rvalue stream extraction should use perfect forwarding
+  // 1203. More useful rvalue stream insertion
+
+#if __cpp_lib_concepts
+  template<typename _Is, typename _Tp>
+    requires __derived_from_ios_base<_Is>
+      && requires (_Is& __is, _Tp&& __t) { __is >> std::forward<_Tp>(__t); }
+    using __rvalue_stream_extraction_t = _Is&&;
+#else
+  template<typename _Is, typename _Tp,
+	   typename = _Require_derived_from_ios_base<_Is>,
+	   typename = decltype(std::declval<_Is&>() >> std::declval<_Tp>())>
+    using __rvalue_stream_extraction_t = _Is&&;
+#endif
+
+  /**
+   *  @brief  Generic extractor for rvalue stream
+   *  @param  __is  An input stream.
+   *  @param  __x  A reference to the extraction target.
+   *  @return  __is
+   *
+   *  This is just a forwarding function to allow extraction from
+   *  rvalue streams since they won't bind to the extractor functions
+   *  that take an lvalue reference.
+  */
+  template<typename _Istream, typename _Tp>
+    inline __rvalue_stream_extraction_t<_Istream, _Tp>
+    operator>>(_Istream&& __is, _Tp&& __x)
+    {
+      __is >> std::forward<_Tp>(__x);
+      return std::move(__is);
+    }
+#endif // C++11
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#include <bits/istream.tcc>
+
+#endif	/* _GLIBCXX_ISTREAM */
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@@ -0,0 +1,73 @@
+// <iterator> -*- C++ -*-
+
+// Copyright (C) 2001-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/*
+ *
+ * Copyright (c) 1994
+ * Hewlett-Packard Company
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Hewlett-Packard Company makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ *
+ *
+ * Copyright (c) 1996,1997
+ * Silicon Graphics Computer Systems, Inc.
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Silicon Graphics makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ */
+
+/** @file include/iterator
+ *  This is a Standard C++ Library header.
+ */
+
+#ifndef _GLIBCXX_ITERATOR
+#define _GLIBCXX_ITERATOR 1
+
+#pragma GCC system_header
+
+#include <bits/c++config.h>
+#include <bits/stl_iterator_base_types.h>
+#include <bits/stl_iterator_base_funcs.h>
+#include <bits/stl_iterator.h>
+#include <iosfwd>
+#include <bits/stream_iterator.h>
+#include <bits/streambuf_iterator.h>
+#include <bits/range_access.h>
+
+#if __cplusplus >= 201402L && ! defined _GLIBCXX_DEBUG // PR libstdc++/70303
+# define __cpp_lib_null_iterators 201304L
+#endif
+
+#endif /* _GLIBCXX_ITERATOR */
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+// The template and inlines for the numeric_limits classes. -*- C++ -*-
+
+// Copyright (C) 1999-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file include/limits
+ *  This is a Standard C++ Library header.
+ */
+
+// Note: this is not a conforming implementation.
+// Written by Gabriel Dos Reis <gdr@codesourcery.com>
+
+//
+// ISO 14882:1998
+// 18.2.1
+//
+
+#ifndef _GLIBCXX_NUMERIC_LIMITS
+#define _GLIBCXX_NUMERIC_LIMITS 1
+
+#pragma GCC system_header
+
+#include <bits/c++config.h>
+
+//
+// The numeric_limits<> traits document implementation-defined aspects
+// of fundamental arithmetic data types (integers and floating points).
+// From Standard C++ point of view, there are 14 such types:
+//   * integers
+//         bool							(1)
+//         char, signed char, unsigned char, wchar_t            (4)
+//         short, unsigned short				(2)
+//         int, unsigned					(2)
+//         long, unsigned long					(2)
+//
+//   * floating points
+//         float						(1)
+//         double						(1)
+//         long double						(1)
+//
+// GNU C++ understands (where supported by the host C-library)
+//   * integer
+//         long long, unsigned long long			(2)
+//
+// which brings us to 16 fundamental arithmetic data types in GNU C++.
+//
+//
+// Since a numeric_limits<> is a bit tricky to get right, we rely on
+// an interface composed of macros which should be defined in config/os
+// or config/cpu when they differ from the generic (read arbitrary)
+// definitions given here.
+//
+
+// These values can be overridden in the target configuration file.
+// The default values are appropriate for many 32-bit targets.
+
+// GCC only intrinsically supports modulo integral types.  The only remaining
+// integral exceptional values is division by zero.  Only targets that do not
+// signal division by zero in some "hard to ignore" way should use false.
+#ifndef __glibcxx_integral_traps
+# define __glibcxx_integral_traps true
+#endif
+
+// float
+//
+
+// Default values.  Should be overridden in configuration files if necessary.
+
+#ifndef __glibcxx_float_has_denorm_loss
+#  define __glibcxx_float_has_denorm_loss false
+#endif
+#ifndef __glibcxx_float_traps
+#  define __glibcxx_float_traps false
+#endif
+#ifndef __glibcxx_float_tinyness_before
+#  define __glibcxx_float_tinyness_before false
+#endif
+
+// double
+
+// Default values.  Should be overridden in configuration files if necessary.
+
+#ifndef __glibcxx_double_has_denorm_loss
+#  define __glibcxx_double_has_denorm_loss false
+#endif
+#ifndef __glibcxx_double_traps
+#  define __glibcxx_double_traps false
+#endif
+#ifndef __glibcxx_double_tinyness_before
+#  define __glibcxx_double_tinyness_before false
+#endif
+
+// long double
+
+// Default values.  Should be overridden in configuration files if necessary.
+
+#ifndef __glibcxx_long_double_has_denorm_loss
+#  define __glibcxx_long_double_has_denorm_loss false
+#endif
+#ifndef __glibcxx_long_double_traps
+#  define __glibcxx_long_double_traps false
+#endif
+#ifndef __glibcxx_long_double_tinyness_before
+#  define __glibcxx_long_double_tinyness_before false
+#endif
+
+// You should not need to define any macros below this point.
+
+#define __glibcxx_signed_b(T,B)	((T)(-1) < 0)
+
+#define __glibcxx_min_b(T,B)					\
+  (__glibcxx_signed_b (T,B) ? -__glibcxx_max_b (T,B) - 1 : (T)0)
+
+#define __glibcxx_max_b(T,B)						\
+  (__glibcxx_signed_b (T,B) ?						\
+   (((((T)1 << (__glibcxx_digits_b (T,B) - 1)) - 1) << 1) + 1) : ~(T)0)
+
+#define __glibcxx_digits_b(T,B)				\
+  (B - __glibcxx_signed_b (T,B))
+
+// The fraction 643/2136 approximates log10(2) to 7 significant digits.
+#define __glibcxx_digits10_b(T,B)		\
+  (__glibcxx_digits_b (T,B) * 643L / 2136)
+
+#define __glibcxx_signed(T) \
+  __glibcxx_signed_b (T, sizeof(T) * __CHAR_BIT__)
+#define __glibcxx_min(T) \
+  __glibcxx_min_b (T, sizeof(T) * __CHAR_BIT__)
+#define __glibcxx_max(T) \
+  __glibcxx_max_b (T, sizeof(T) * __CHAR_BIT__)
+#define __glibcxx_digits(T) \
+  __glibcxx_digits_b (T, sizeof(T) * __CHAR_BIT__)
+#define __glibcxx_digits10(T) \
+  __glibcxx_digits10_b (T, sizeof(T) * __CHAR_BIT__)
+
+#define __glibcxx_max_digits10(T) \
+  (2 + (T) * 643L / 2136)
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /**
+   *  @brief Describes the rounding style for floating-point types.
+   *
+   *  This is used in the std::numeric_limits class.
+  */
+  enum float_round_style
+  {
+    round_indeterminate       = -1,    /// Intermediate.
+    round_toward_zero         = 0,     /// To zero.
+    round_to_nearest          = 1,     /// To the nearest representable value.
+    round_toward_infinity     = 2,     /// To infinity.
+    round_toward_neg_infinity = 3      /// To negative infinity.
+  };
+
+  /**
+   *  @brief Describes the denormalization for floating-point types.
+   *
+   *  These values represent the presence or absence of a variable number
+   *  of exponent bits.  This type is used in the std::numeric_limits class.
+  */
+  enum float_denorm_style
+  {
+    /// Indeterminate at compile time whether denormalized values are allowed.
+    denorm_indeterminate = -1,
+    /// The type does not allow denormalized values.
+    denorm_absent        = 0,
+    /// The type allows denormalized values.
+    denorm_present       = 1
+  };
+
+  /**
+   *  @brief Part of std::numeric_limits.
+   *
+   *  The @c static @c const members are usable as integral constant
+   *  expressions.
+   *
+   *  @note This is a separate class for purposes of efficiency; you
+   *        should only access these members as part of an instantiation
+   *        of the std::numeric_limits class.
+  */
+  struct __numeric_limits_base
+  {
+    /** This will be true for all fundamental types (which have
+	specializations), and false for everything else.  */
+    static _GLIBCXX_USE_CONSTEXPR bool is_specialized = false;
+
+    /** The number of @c radix digits that be represented without change:  for
+	integer types, the number of non-sign bits in the mantissa; for
+	floating types, the number of @c radix digits in the mantissa.  */
+    static _GLIBCXX_USE_CONSTEXPR int digits = 0;
+
+    /** The number of base 10 digits that can be represented without change. */
+    static _GLIBCXX_USE_CONSTEXPR int digits10 = 0;
+
+#if __cplusplus >= 201103L
+    /** The number of base 10 digits required to ensure that values which
+	differ are always differentiated.  */
+    static constexpr int max_digits10 = 0;
+#endif
+
+    /** True if the type is signed.  */
+    static _GLIBCXX_USE_CONSTEXPR bool is_signed = false;
+
+    /** True if the type is integer.  */
+    static _GLIBCXX_USE_CONSTEXPR bool is_integer = false;
+
+    /** True if the type uses an exact representation. All integer types are
+	exact, but not all exact types are integer.  For example, rational and
+	fixed-exponent representations are exact but not integer. */
+    static _GLIBCXX_USE_CONSTEXPR bool is_exact = false;
+
+    /** For integer types, specifies the base of the representation.  For
+	floating types, specifies the base of the exponent representation.  */
+    static _GLIBCXX_USE_CONSTEXPR int radix = 0;
+
+    /** The minimum negative integer such that @c radix raised to the power of
+	(one less than that integer) is a normalized floating point number.  */
+    static _GLIBCXX_USE_CONSTEXPR int min_exponent = 0;
+
+    /** The minimum negative integer such that 10 raised to that power is in
+	the range of normalized floating point numbers.  */
+    static _GLIBCXX_USE_CONSTEXPR int min_exponent10 = 0;
+
+    /** The maximum positive integer such that @c radix raised to the power of
+	(one less than that integer) is a representable finite floating point
+	number.  */
+    static _GLIBCXX_USE_CONSTEXPR int max_exponent = 0;
+
+    /** The maximum positive integer such that 10 raised to that power is in
+	the range of representable finite floating point numbers.  */
+    static _GLIBCXX_USE_CONSTEXPR int max_exponent10 = 0;
+
+    /** True if the type has a representation for positive infinity.  */
+    static _GLIBCXX_USE_CONSTEXPR bool has_infinity = false;
+
+    /** True if the type has a representation for a quiet (non-signaling)
+	Not a Number.  */
+    static _GLIBCXX_USE_CONSTEXPR bool has_quiet_NaN = false;
+
+    /** True if the type has a representation for a signaling
+	Not a Number.  */
+    static _GLIBCXX_USE_CONSTEXPR bool has_signaling_NaN = false;
+
+    /** See std::float_denorm_style for more information.  */
+    static _GLIBCXX_USE_CONSTEXPR float_denorm_style has_denorm = denorm_absent;
+
+    /** True if loss of accuracy is detected as a denormalization loss,
+	rather than as an inexact result. */
+    static _GLIBCXX_USE_CONSTEXPR bool has_denorm_loss = false;
+
+    /** True if-and-only-if the type adheres to the IEC 559 standard, also
+	known as IEEE 754.  (Only makes sense for floating point types.)  */
+    static _GLIBCXX_USE_CONSTEXPR bool is_iec559 = false;
+
+    /** True if the set of values representable by the type is
+	finite.  All built-in types are bounded, this member would be
+	false for arbitrary precision types. */
+    static _GLIBCXX_USE_CONSTEXPR bool is_bounded = false;
+
+    /** True if the type is @e modulo. A type is modulo if, for any
+	operation involving +, -, or * on values of that type whose
+	result would fall outside the range [min(),max()], the value
+	returned differs from the true value by an integer multiple of
+	max() - min() + 1. On most machines, this is false for floating
+	types, true for unsigned integers, and true for signed integers.
+	See PR22200 about signed integers.  */
+    static _GLIBCXX_USE_CONSTEXPR bool is_modulo = false;
+
+    /** True if trapping is implemented for this type.  */
+    static _GLIBCXX_USE_CONSTEXPR bool traps = false;
+
+    /** True if tininess is detected before rounding.  (see IEC 559)  */
+    static _GLIBCXX_USE_CONSTEXPR bool tinyness_before = false;
+
+    /** See std::float_round_style for more information.  This is only
+	meaningful for floating types; integer types will all be
+	round_toward_zero.  */
+    static _GLIBCXX_USE_CONSTEXPR float_round_style round_style =
+						    round_toward_zero;
+  };
+
+  /**
+   *  @brief Properties of fundamental types.
+   *
+   *  This class allows a program to obtain information about the
+   *  representation of a fundamental type on a given platform.  For
+   *  non-fundamental types, the functions will return 0 and the data
+   *  members will all be @c false.
+  */
+  template<typename _Tp>
+    struct numeric_limits : public __numeric_limits_base
+    {
+      /** The minimum finite value, or for floating types with
+	  denormalization, the minimum positive normalized value.  */
+      static _GLIBCXX_CONSTEXPR _Tp
+      min() _GLIBCXX_USE_NOEXCEPT { return _Tp(); }
+
+      /** The maximum finite value.  */
+      static _GLIBCXX_CONSTEXPR _Tp
+      max() _GLIBCXX_USE_NOEXCEPT { return _Tp(); }
+
+#if __cplusplus >= 201103L
+      /** A finite value x such that there is no other finite value y
+       *  where y < x.  */
+      static constexpr _Tp
+      lowest() noexcept { return _Tp(); }
+#endif
+
+      /** The @e machine @e epsilon:  the difference between 1 and the least
+	  value greater than 1 that is representable.  */
+      static _GLIBCXX_CONSTEXPR _Tp
+      epsilon() _GLIBCXX_USE_NOEXCEPT { return _Tp(); }
+
+      /** The maximum rounding error measurement (see LIA-1).  */
+      static _GLIBCXX_CONSTEXPR _Tp
+      round_error() _GLIBCXX_USE_NOEXCEPT { return _Tp(); }
+
+      /** The representation of positive infinity, if @c has_infinity.  */
+      static _GLIBCXX_CONSTEXPR _Tp
+      infinity() _GLIBCXX_USE_NOEXCEPT { return _Tp(); }
+
+      /** The representation of a quiet Not a Number,
+	  if @c has_quiet_NaN. */
+      static _GLIBCXX_CONSTEXPR _Tp
+      quiet_NaN() _GLIBCXX_USE_NOEXCEPT { return _Tp(); }
+
+      /** The representation of a signaling Not a Number, if
+	  @c has_signaling_NaN. */
+      static _GLIBCXX_CONSTEXPR _Tp
+      signaling_NaN() _GLIBCXX_USE_NOEXCEPT { return _Tp(); }
+
+      /** The minimum positive denormalized value.  For types where
+	  @c has_denorm is false, this is the minimum positive normalized
+	  value.  */
+      static _GLIBCXX_CONSTEXPR _Tp
+      denorm_min() _GLIBCXX_USE_NOEXCEPT { return _Tp(); }
+    };
+
+  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+  // 559. numeric_limits<const T>
+
+  template<typename _Tp>
+    struct numeric_limits<const _Tp>
+    : public numeric_limits<_Tp> { };
+
+  template<typename _Tp>
+    struct numeric_limits<volatile _Tp>
+    : public numeric_limits<_Tp> { };
+
+  template<typename _Tp>
+    struct numeric_limits<const volatile _Tp>
+    : public numeric_limits<_Tp> { };
+
+  // Now there follow 16 explicit specializations.  Yes, 16.  Make sure
+  // you get the count right. (18 in C++11 mode, with char16_t and char32_t.)
+  // (+1 if char8_t is enabled.)
+
+  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+  // 184. numeric_limits<bool> wording problems
+
+  /// numeric_limits<bool> specialization.
+  template<>
+    struct numeric_limits<bool>
+    {
+      static _GLIBCXX_USE_CONSTEXPR bool is_specialized = true;
+
+      static _GLIBCXX_CONSTEXPR bool
+      min() _GLIBCXX_USE_NOEXCEPT { return false; }
+
+      static _GLIBCXX_CONSTEXPR bool
+      max() _GLIBCXX_USE_NOEXCEPT { return true; }
+
+#if __cplusplus >= 201103L
+      static constexpr bool
+      lowest() noexcept { return min(); }
+#endif
+      static _GLIBCXX_USE_CONSTEXPR int digits = 1;
+      static _GLIBCXX_USE_CONSTEXPR int digits10 = 0;
+#if __cplusplus >= 201103L
+      static constexpr int max_digits10 = 0;
+#endif
+      static _GLIBCXX_USE_CONSTEXPR bool is_signed = false;
+      static _GLIBCXX_USE_CONSTEXPR bool is_integer = true;
+      static _GLIBCXX_USE_CONSTEXPR bool is_exact = true;
+      static _GLIBCXX_USE_CONSTEXPR int radix = 2;
+
+      static _GLIBCXX_CONSTEXPR bool
+      epsilon() _GLIBCXX_USE_NOEXCEPT { return false; }
+
+      static _GLIBCXX_CONSTEXPR bool
+      round_error() _GLIBCXX_USE_NOEXCEPT { return false; }
+
+      static _GLIBCXX_USE_CONSTEXPR int min_exponent = 0;
+      static _GLIBCXX_USE_CONSTEXPR int min_exponent10 = 0;
+      static _GLIBCXX_USE_CONSTEXPR int max_exponent = 0;
+      static _GLIBCXX_USE_CONSTEXPR int max_exponent10 = 0;
+
+      static _GLIBCXX_USE_CONSTEXPR bool has_infinity = false;
+      static _GLIBCXX_USE_CONSTEXPR bool has_quiet_NaN = false;
+      static _GLIBCXX_USE_CONSTEXPR bool has_signaling_NaN = false;
+      static _GLIBCXX_USE_CONSTEXPR float_denorm_style has_denorm
+       = denorm_absent;
+      static _GLIBCXX_USE_CONSTEXPR bool has_denorm_loss = false;
+
+      static _GLIBCXX_CONSTEXPR bool
+      infinity() _GLIBCXX_USE_NOEXCEPT { return false; }
+
+      static _GLIBCXX_CONSTEXPR bool
+      quiet_NaN() _GLIBCXX_USE_NOEXCEPT { return false; }
+
+      static _GLIBCXX_CONSTEXPR bool
+      signaling_NaN() _GLIBCXX_USE_NOEXCEPT { return false; }
+
+      static _GLIBCXX_CONSTEXPR bool
+      denorm_min() _GLIBCXX_USE_NOEXCEPT { return false; }
+
+      static _GLIBCXX_USE_CONSTEXPR bool is_iec559 = false;
+      static _GLIBCXX_USE_CONSTEXPR bool is_bounded = true;
+      static _GLIBCXX_USE_CONSTEXPR bool is_modulo = false;
+
+      // It is not clear what it means for a boolean type to trap.
+      // This is a DR on the LWG issue list.  Here, I use integer
+      // promotion semantics.
+      static _GLIBCXX_USE_CONSTEXPR bool traps = __glibcxx_integral_traps;
+      static _GLIBCXX_USE_CONSTEXPR bool tinyness_before = false;
+      static _GLIBCXX_USE_CONSTEXPR float_round_style round_style
+       = round_toward_zero;
+    };
+
+  /// numeric_limits<char> specialization.
+  template<>
+    struct numeric_limits<char>
+    {
+      static _GLIBCXX_USE_CONSTEXPR bool is_specialized = true;
+
+      static _GLIBCXX_CONSTEXPR char
+      min() _GLIBCXX_USE_NOEXCEPT { return __glibcxx_min(char); }
+
+      static _GLIBCXX_CONSTEXPR char
+      max() _GLIBCXX_USE_NOEXCEPT { return __glibcxx_max(char); }
+
+#if __cplusplus >= 201103L
+      static constexpr char
+      lowest() noexcept { return min(); }
+#endif
+
+      static _GLIBCXX_USE_CONSTEXPR int digits = __glibcxx_digits (char);
+      static _GLIBCXX_USE_CONSTEXPR int digits10 = __glibcxx_digits10 (char);
+#if __cplusplus >= 201103L
+      static constexpr int max_digits10 = 0;
+#endif
+      static _GLIBCXX_USE_CONSTEXPR bool is_signed = __glibcxx_signed (char);
+      static _GLIBCXX_USE_CONSTEXPR bool is_integer = true;
+      static _GLIBCXX_USE_CONSTEXPR bool is_exact = true;
+      static _GLIBCXX_USE_CONSTEXPR int radix = 2;
+
+      static _GLIBCXX_CONSTEXPR char
+      epsilon() _GLIBCXX_USE_NOEXCEPT { return 0; }
+
+      static _GLIBCXX_CONSTEXPR char
+      round_error() _GLIBCXX_USE_NOEXCEPT { return 0; }
+
+      static _GLIBCXX_USE_CONSTEXPR int min_exponent = 0;
+      static _GLIBCXX_USE_CONSTEXPR int min_exponent10 = 0;
+      static _GLIBCXX_USE_CONSTEXPR int max_exponent = 0;
+      static _GLIBCXX_USE_CONSTEXPR int max_exponent10 = 0;
+
+      static _GLIBCXX_USE_CONSTEXPR bool has_infinity = false;
+      static _GLIBCXX_USE_CONSTEXPR bool has_quiet_NaN = false;
+      static _GLIBCXX_USE_CONSTEXPR bool has_signaling_NaN = false;
+      static _GLIBCXX_USE_CONSTEXPR float_denorm_style has_denorm
+       = denorm_absent;
+      static _GLIBCXX_USE_CONSTEXPR bool has_denorm_loss = false;
+
+      static _GLIBCXX_CONSTEXPR
+      char infinity() _GLIBCXX_USE_NOEXCEPT { return char(); }
+
+      static _GLIBCXX_CONSTEXPR char
+      quiet_NaN() _GLIBCXX_USE_NOEXCEPT { return char(); }
+
+      static _GLIBCXX_CONSTEXPR char
+      signaling_NaN() _GLIBCXX_USE_NOEXCEPT { return char(); }
+
+      static _GLIBCXX_CONSTEXPR char
+      denorm_min() _GLIBCXX_USE_NOEXCEPT { return static_cast<char>(0); }
+
+      static _GLIBCXX_USE_CONSTEXPR bool is_iec559 = false;
+      static _GLIBCXX_USE_CONSTEXPR bool is_bounded = true;
+      static _GLIBCXX_USE_CONSTEXPR bool is_modulo = !is_signed;
+
+      static _GLIBCXX_USE_CONSTEXPR bool traps = __glibcxx_integral_traps;
+      static _GLIBCXX_USE_CONSTEXPR bool tinyness_before = false;
+      static _GLIBCXX_USE_CONSTEXPR float_round_style round_style
+       = round_toward_zero;
+    };
+
+  /// numeric_limits<signed char> specialization.
+  template<>
+    struct numeric_limits<signed char>
+    {
+      static _GLIBCXX_USE_CONSTEXPR bool is_specialized = true;
+
+      static _GLIBCXX_CONSTEXPR signed char
+      min() _GLIBCXX_USE_NOEXCEPT { return -__SCHAR_MAX__ - 1; }
+
+      static _GLIBCXX_CONSTEXPR signed char
+      max() _GLIBCXX_USE_NOEXCEPT { return __SCHAR_MAX__; }
+
+#if __cplusplus >= 201103L
+      static constexpr signed char
+      lowest() noexcept { return min(); }
+#endif
+
+      static _GLIBCXX_USE_CONSTEXPR int digits = __glibcxx_digits (signed char);
+      static _GLIBCXX_USE_CONSTEXPR int digits10
+       = __glibcxx_digits10 (signed char);
+#if __cplusplus >= 201103L
+      static constexpr int max_digits10 = 0;
+#endif
+      static _GLIBCXX_USE_CONSTEXPR bool is_signed = true;
+      static _GLIBCXX_USE_CONSTEXPR bool is_integer = true;
+      static _GLIBCXX_USE_CONSTEXPR bool is_exact = true;
+      static _GLIBCXX_USE_CONSTEXPR int radix = 2;
+
+      static _GLIBCXX_CONSTEXPR signed char
+      epsilon() _GLIBCXX_USE_NOEXCEPT { return 0; }
+
+      static _GLIBCXX_CONSTEXPR signed char
+      round_error() _GLIBCXX_USE_NOEXCEPT { return 0; }
+
+      static _GLIBCXX_USE_CONSTEXPR int min_exponent = 0;
+      static _GLIBCXX_USE_CONSTEXPR int min_exponent10 = 0;
+      static _GLIBCXX_USE_CONSTEXPR int max_exponent = 0;
+      static _GLIBCXX_USE_CONSTEXPR int max_exponent10 = 0;
+
+      static _GLIBCXX_USE_CONSTEXPR bool has_infinity = false;
+      static _GLIBCXX_USE_CONSTEXPR bool has_quiet_NaN = false;
+      static _GLIBCXX_USE_CONSTEXPR bool has_signaling_NaN = false;
+      static _GLIBCXX_USE_CONSTEXPR float_denorm_style has_denorm
+       = denorm_absent;
+      static _GLIBCXX_USE_CONSTEXPR bool has_denorm_loss = false;
+
+      static _GLIBCXX_CONSTEXPR signed char
+      infinity() _GLIBCXX_USE_NOEXCEPT { return static_cast<signed char>(0); }
+
+      static _GLIBCXX_CONSTEXPR signed char
+      quiet_NaN() _GLIBCXX_USE_NOEXCEPT { return static_cast<signed char>(0); }
+
+      static _GLIBCXX_CONSTEXPR signed char
+      signaling_NaN() _GLIBCXX_USE_NOEXCEPT
+      { return static_cast<signed char>(0); }
+
+      static _GLIBCXX_CONSTEXPR signed char
+      denorm_min() _GLIBCXX_USE_NOEXCEPT
+      { return static_cast<signed char>(0); }
+
+      static _GLIBCXX_USE_CONSTEXPR bool is_iec559 = false;
+      static _GLIBCXX_USE_CONSTEXPR bool is_bounded = true;
+      static _GLIBCXX_USE_CONSTEXPR bool is_modulo = false;
+
+      static _GLIBCXX_USE_CONSTEXPR bool traps = __glibcxx_integral_traps;
+      static _GLIBCXX_USE_CONSTEXPR bool tinyness_before = false;
+      static _GLIBCXX_USE_CONSTEXPR float_round_style round_style
+       = round_toward_zero;
+    };
+
+  /// numeric_limits<unsigned char> specialization.
+  template<>
+    struct numeric_limits<unsigned char>
+    {
+      static _GLIBCXX_USE_CONSTEXPR bool is_specialized = true;
+
+      static _GLIBCXX_CONSTEXPR unsigned char
+      min() _GLIBCXX_USE_NOEXCEPT { return 0; }
+
+      static _GLIBCXX_CONSTEXPR unsigned char
+      max() _GLIBCXX_USE_NOEXCEPT { return __SCHAR_MAX__ * 2U + 1; }
+
+#if __cplusplus >= 201103L
+      static constexpr unsigned char
+      lowest() noexcept { return min(); }
+#endif
+
+      static _GLIBCXX_USE_CONSTEXPR int digits
+       = __glibcxx_digits (unsigned char);
+      static _GLIBCXX_USE_CONSTEXPR int digits10
+       = __glibcxx_digits10 (unsigned char);
+#if __cplusplus >= 201103L
+      static constexpr int max_digits10 = 0;
+#endif
+      static _GLIBCXX_USE_CONSTEXPR bool is_signed = false;
+      static _GLIBCXX_USE_CONSTEXPR bool is_integer = true;
+      static _GLIBCXX_USE_CONSTEXPR bool is_exact = true;
+      static _GLIBCXX_USE_CONSTEXPR int radix = 2;
+
+      static _GLIBCXX_CONSTEXPR unsigned char
+      epsilon() _GLIBCXX_USE_NOEXCEPT { return 0; }
+
+      static _GLIBCXX_CONSTEXPR unsigned char
+      round_error() _GLIBCXX_USE_NOEXCEPT { return 0; }
+
+      static _GLIBCXX_USE_CONSTEXPR int min_exponent = 0;
+      static _GLIBCXX_USE_CONSTEXPR int min_exponent10 = 0;
+      static _GLIBCXX_USE_CONSTEXPR int max_exponent = 0;
+      static _GLIBCXX_USE_CONSTEXPR int max_exponent10 = 0;
+
+      static _GLIBCXX_USE_CONSTEXPR bool has_infinity = false;
+      static _GLIBCXX_USE_CONSTEXPR bool has_quiet_NaN = false;
+      static _GLIBCXX_USE_CONSTEXPR bool has_signaling_NaN = false;
+      static _GLIBCXX_USE_CONSTEXPR float_denorm_style has_denorm
+       = denorm_absent;
+      static _GLIBCXX_USE_CONSTEXPR bool has_denorm_loss = false;
+
+      static _GLIBCXX_CONSTEXPR unsigned char
+      infinity() _GLIBCXX_USE_NOEXCEPT
+      { return static_cast<unsigned char>(0); }
+
+      static _GLIBCXX_CONSTEXPR unsigned char
+      quiet_NaN() _GLIBCXX_USE_NOEXCEPT
+      { return static_cast<unsigned char>(0); }
+
+      static _GLIBCXX_CONSTEXPR unsigned char
+      signaling_NaN() _GLIBCXX_USE_NOEXCEPT
+      { return static_cast<unsigned char>(0); }
+
+      static _GLIBCXX_CONSTEXPR unsigned char
+      denorm_min() _GLIBCXX_USE_NOEXCEPT
+      { return static_cast<unsigned char>(0); }
+
+      static _GLIBCXX_USE_CONSTEXPR bool is_iec559 = false;
+      static _GLIBCXX_USE_CONSTEXPR bool is_bounded = true;
+      static _GLIBCXX_USE_CONSTEXPR bool is_modulo = true;
+
+      static _GLIBCXX_USE_CONSTEXPR bool traps = __glibcxx_integral_traps;
+      static _GLIBCXX_USE_CONSTEXPR bool tinyness_before = false;
+      static _GLIBCXX_USE_CONSTEXPR float_round_style round_style
+       = round_toward_zero;
+    };
+
+  /// numeric_limits<wchar_t> specialization.
+  template<>
+    struct numeric_limits<wchar_t>
+    {
+      static _GLIBCXX_USE_CONSTEXPR bool is_specialized = true;
+
+      static _GLIBCXX_CONSTEXPR wchar_t
+      min() _GLIBCXX_USE_NOEXCEPT { return __glibcxx_min (wchar_t); }
+
+      static _GLIBCXX_CONSTEXPR wchar_t
+      max() _GLIBCXX_USE_NOEXCEPT { return __glibcxx_max (wchar_t); }
+
+#if __cplusplus >= 201103L
+      static constexpr wchar_t
+      lowest() noexcept { return min(); }
+#endif
+
+      static _GLIBCXX_USE_CONSTEXPR int digits = __glibcxx_digits (wchar_t);
+      static _GLIBCXX_USE_CONSTEXPR int digits10
+       = __glibcxx_digits10 (wchar_t);
+#if __cplusplus >= 201103L
+      static constexpr int max_digits10 = 0;
+#endif
+      static _GLIBCXX_USE_CONSTEXPR bool is_signed = __glibcxx_signed (wchar_t);
+      static _GLIBCXX_USE_CONSTEXPR bool is_integer = true;
+      static _GLIBCXX_USE_CONSTEXPR bool is_exact = true;
+      static _GLIBCXX_USE_CONSTEXPR int radix = 2;
+
+      static _GLIBCXX_CONSTEXPR wchar_t
+      epsilon() _GLIBCXX_USE_NOEXCEPT { return 0; }
+
+      static _GLIBCXX_CONSTEXPR wchar_t
+      round_error() _GLIBCXX_USE_NOEXCEPT { return 0; }
+
+      static _GLIBCXX_USE_CONSTEXPR int min_exponent = 0;
+      static _GLIBCXX_USE_CONSTEXPR int min_exponent10 = 0;
+      static _GLIBCXX_USE_CONSTEXPR int max_exponent = 0;
+      static _GLIBCXX_USE_CONSTEXPR int max_exponent10 = 0;
+
+      static _GLIBCXX_USE_CONSTEXPR bool has_infinity = false;
+      static _GLIBCXX_USE_CONSTEXPR bool has_quiet_NaN = false;
+      static _GLIBCXX_USE_CONSTEXPR bool has_signaling_NaN = false;
+      static _GLIBCXX_USE_CONSTEXPR float_denorm_style has_denorm
+       = denorm_absent;
+      static _GLIBCXX_USE_CONSTEXPR bool has_denorm_loss = false;
+
+      static _GLIBCXX_CONSTEXPR wchar_t
+      infinity() _GLIBCXX_USE_NOEXCEPT { return wchar_t(); }
+
+      static _GLIBCXX_CONSTEXPR wchar_t
+      quiet_NaN() _GLIBCXX_USE_NOEXCEPT { return wchar_t(); }
+
+      static _GLIBCXX_CONSTEXPR wchar_t
+      signaling_NaN() _GLIBCXX_USE_NOEXCEPT { return wchar_t(); }
+
+      static _GLIBCXX_CONSTEXPR wchar_t
+      denorm_min() _GLIBCXX_USE_NOEXCEPT { return wchar_t(); }
+
+      static _GLIBCXX_USE_CONSTEXPR bool is_iec559 = false;
+      static _GLIBCXX_USE_CONSTEXPR bool is_bounded = true;
+      static _GLIBCXX_USE_CONSTEXPR bool is_modulo = !is_signed;
+
+      static _GLIBCXX_USE_CONSTEXPR bool traps = __glibcxx_integral_traps;
+      static _GLIBCXX_USE_CONSTEXPR bool tinyness_before = false;
+      static _GLIBCXX_USE_CONSTEXPR float_round_style round_style
+       = round_toward_zero;
+    };
+
+#if _GLIBCXX_USE_CHAR8_T
+  /// numeric_limits<char8_t> specialization.
+  template<>
+    struct numeric_limits<char8_t>
+    {
+      static _GLIBCXX_USE_CONSTEXPR bool is_specialized = true;
+
+      static _GLIBCXX_CONSTEXPR char8_t
+      min() _GLIBCXX_USE_NOEXCEPT { return __glibcxx_min (char8_t); }
+
+      static _GLIBCXX_CONSTEXPR char8_t
+      max() _GLIBCXX_USE_NOEXCEPT { return __glibcxx_max (char8_t); }
+
+      static _GLIBCXX_CONSTEXPR char8_t
+      lowest() _GLIBCXX_USE_NOEXCEPT { return min(); }
+
+      static _GLIBCXX_USE_CONSTEXPR int digits = __glibcxx_digits (char8_t);
+      static _GLIBCXX_USE_CONSTEXPR int digits10 = __glibcxx_digits10 (char8_t);
+      static _GLIBCXX_USE_CONSTEXPR int max_digits10 = 0;
+      static _GLIBCXX_USE_CONSTEXPR bool is_signed = __glibcxx_signed (char8_t);
+      static _GLIBCXX_USE_CONSTEXPR bool is_integer = true;
+      static _GLIBCXX_USE_CONSTEXPR bool is_exact = true;
+      static _GLIBCXX_USE_CONSTEXPR int radix = 2;
+
+      static _GLIBCXX_CONSTEXPR char8_t
+      epsilon() _GLIBCXX_USE_NOEXCEPT { return 0; }
+
+      static _GLIBCXX_CONSTEXPR char8_t
+      round_error() _GLIBCXX_USE_NOEXCEPT { return 0; }
+
+      static _GLIBCXX_USE_CONSTEXPR int min_exponent = 0;
+      static _GLIBCXX_USE_CONSTEXPR int min_exponent10 = 0;
+      static _GLIBCXX_USE_CONSTEXPR int max_exponent = 0;
+      static _GLIBCXX_USE_CONSTEXPR int max_exponent10 = 0;
+
+      static _GLIBCXX_USE_CONSTEXPR bool has_infinity = false;
+      static _GLIBCXX_USE_CONSTEXPR bool has_quiet_NaN = false;
+      static _GLIBCXX_USE_CONSTEXPR bool has_signaling_NaN = false;
+      static _GLIBCXX_USE_CONSTEXPR float_denorm_style has_denorm
+	= denorm_absent;
+      static _GLIBCXX_USE_CONSTEXPR bool has_denorm_loss = false;
+
+      static _GLIBCXX_CONSTEXPR char8_t
+      infinity() _GLIBCXX_USE_NOEXCEPT { return char8_t(); }
+
+      static _GLIBCXX_CONSTEXPR char8_t
+      quiet_NaN() _GLIBCXX_USE_NOEXCEPT { return char8_t(); }
+
+      static _GLIBCXX_CONSTEXPR char8_t
+      signaling_NaN() _GLIBCXX_USE_NOEXCEPT { return char8_t(); }
+
+      static _GLIBCXX_CONSTEXPR char8_t
+      denorm_min() _GLIBCXX_USE_NOEXCEPT { return char8_t(); }
+
+      static _GLIBCXX_USE_CONSTEXPR bool is_iec559 = false;
+      static _GLIBCXX_USE_CONSTEXPR bool is_bounded = true;
+      static _GLIBCXX_USE_CONSTEXPR bool is_modulo = !is_signed;
+
+      static _GLIBCXX_USE_CONSTEXPR bool traps = __glibcxx_integral_traps;
+      static _GLIBCXX_USE_CONSTEXPR bool tinyness_before = false;
+      static _GLIBCXX_USE_CONSTEXPR float_round_style round_style
+	= round_toward_zero;
+    };
+#endif
+
+#if __cplusplus >= 201103L
+  /// numeric_limits<char16_t> specialization.
+  template<>
+    struct numeric_limits<char16_t>
+    {
+      static constexpr bool is_specialized = true;
+
+      static constexpr char16_t
+      min() noexcept { return __glibcxx_min (char16_t); }
+
+      static constexpr char16_t
+      max() noexcept { return __glibcxx_max (char16_t); }
+
+      static constexpr char16_t
+      lowest() noexcept { return min(); }
+
+      static constexpr int digits = __glibcxx_digits (char16_t);
+      static constexpr int digits10 = __glibcxx_digits10 (char16_t);
+      static constexpr int max_digits10 = 0;
+      static constexpr bool is_signed = __glibcxx_signed (char16_t);
+      static constexpr bool is_integer = true;
+      static constexpr bool is_exact = true;
+      static constexpr int radix = 2;
+
+      static constexpr char16_t
+      epsilon() noexcept { return 0; }
+
+      static constexpr char16_t
+      round_error() noexcept { return 0; }
+
+      static constexpr int min_exponent = 0;
+      static constexpr int min_exponent10 = 0;
+      static constexpr int max_exponent = 0;
+      static constexpr int max_exponent10 = 0;
+
+      static constexpr bool has_infinity = false;
+      static constexpr bool has_quiet_NaN = false;
+      static constexpr bool has_signaling_NaN = false;
+      static constexpr float_denorm_style has_denorm = denorm_absent;
+      static constexpr bool has_denorm_loss = false;
+
+      static constexpr char16_t
+      infinity() noexcept { return char16_t(); }
+
+      static constexpr char16_t
+      quiet_NaN() noexcept { return char16_t(); }
+
+      static constexpr char16_t
+      signaling_NaN() noexcept { return char16_t(); }
+
+      static constexpr char16_t
+      denorm_min() noexcept { return char16_t(); }
+
+      static constexpr bool is_iec559 = false;
+      static constexpr bool is_bounded = true;
+      static constexpr bool is_modulo = !is_signed;
+
+      static constexpr bool traps = __glibcxx_integral_traps;
+      static constexpr bool tinyness_before = false;
+      static constexpr float_round_style round_style = round_toward_zero;
+    };
+
+  /// numeric_limits<char32_t> specialization.
+  template<>
+    struct numeric_limits<char32_t>
+    {
+      static constexpr bool is_specialized = true;
+
+      static constexpr char32_t
+      min() noexcept { return __glibcxx_min (char32_t); }
+
+      static constexpr char32_t
+      max() noexcept { return __glibcxx_max (char32_t); }
+
+      static constexpr char32_t
+      lowest() noexcept { return min(); }
+
+      static constexpr int digits = __glibcxx_digits (char32_t);
+      static constexpr int digits10 = __glibcxx_digits10 (char32_t);
+      static constexpr int max_digits10 = 0;
+      static constexpr bool is_signed = __glibcxx_signed (char32_t);
+      static constexpr bool is_integer = true;
+      static constexpr bool is_exact = true;
+      static constexpr int radix = 2;
+
+      static constexpr char32_t
+      epsilon() noexcept { return 0; }
+
+      static constexpr char32_t
+      round_error() noexcept { return 0; }
+
+      static constexpr int min_exponent = 0;
+      static constexpr int min_exponent10 = 0;
+      static constexpr int max_exponent = 0;
+      static constexpr int max_exponent10 = 0;
+
+      static constexpr bool has_infinity = false;
+      static constexpr bool has_quiet_NaN = false;
+      static constexpr bool has_signaling_NaN = false;
+      static constexpr float_denorm_style has_denorm = denorm_absent;
+      static constexpr bool has_denorm_loss = false;
+
+      static constexpr char32_t
+      infinity() noexcept { return char32_t(); }
+
+      static constexpr char32_t
+      quiet_NaN() noexcept { return char32_t(); }
+
+      static constexpr char32_t
+      signaling_NaN() noexcept { return char32_t(); }
+
+      static constexpr char32_t
+      denorm_min() noexcept { return char32_t(); }
+
+      static constexpr bool is_iec559 = false;
+      static constexpr bool is_bounded = true;
+      static constexpr bool is_modulo = !is_signed;
+
+      static constexpr bool traps = __glibcxx_integral_traps;
+      static constexpr bool tinyness_before = false;
+      static constexpr float_round_style round_style = round_toward_zero;
+    };
+#endif
+
+  /// numeric_limits<short> specialization.
+  template<>
+    struct numeric_limits<short>
+    {
+      static _GLIBCXX_USE_CONSTEXPR bool is_specialized = true;
+
+      static _GLIBCXX_CONSTEXPR short
+      min() _GLIBCXX_USE_NOEXCEPT { return -__SHRT_MAX__ - 1; }
+
+      static _GLIBCXX_CONSTEXPR short
+      max() _GLIBCXX_USE_NOEXCEPT { return __SHRT_MAX__; }
+
+#if __cplusplus >= 201103L
+      static constexpr short
+      lowest() noexcept { return min(); }
+#endif
+
+      static _GLIBCXX_USE_CONSTEXPR int digits = __glibcxx_digits (short);
+      static _GLIBCXX_USE_CONSTEXPR int digits10 = __glibcxx_digits10 (short);
+#if __cplusplus >= 201103L
+      static constexpr int max_digits10 = 0;
+#endif
+      static _GLIBCXX_USE_CONSTEXPR bool is_signed = true;
+      static _GLIBCXX_USE_CONSTEXPR bool is_integer = true;
+      static _GLIBCXX_USE_CONSTEXPR bool is_exact = true;
+      static _GLIBCXX_USE_CONSTEXPR int radix = 2;
+
+      static _GLIBCXX_CONSTEXPR short
+      epsilon() _GLIBCXX_USE_NOEXCEPT { return 0; }
+
+      static _GLIBCXX_CONSTEXPR short
+      round_error() _GLIBCXX_USE_NOEXCEPT { return 0; }
+
+      static _GLIBCXX_USE_CONSTEXPR int min_exponent = 0;
+      static _GLIBCXX_USE_CONSTEXPR int min_exponent10 = 0;
+      static _GLIBCXX_USE_CONSTEXPR int max_exponent = 0;
+      static _GLIBCXX_USE_CONSTEXPR int max_exponent10 = 0;
+
+      static _GLIBCXX_USE_CONSTEXPR bool has_infinity = false;
+      static _GLIBCXX_USE_CONSTEXPR bool has_quiet_NaN = false;
+      static _GLIBCXX_USE_CONSTEXPR bool has_signaling_NaN = false;
+      static _GLIBCXX_USE_CONSTEXPR float_denorm_style has_denorm
+       = denorm_absent;
+      static _GLIBCXX_USE_CONSTEXPR bool has_denorm_loss = false;
+
+      static _GLIBCXX_CONSTEXPR short
+      infinity() _GLIBCXX_USE_NOEXCEPT { return short(); }
+
+      static _GLIBCXX_CONSTEXPR short
+      quiet_NaN() _GLIBCXX_USE_NOEXCEPT { return short(); }
+
+      static _GLIBCXX_CONSTEXPR short
+      signaling_NaN() _GLIBCXX_USE_NOEXCEPT { return short(); }
+
+      static _GLIBCXX_CONSTEXPR short
+      denorm_min() _GLIBCXX_USE_NOEXCEPT { return short(); }
+
+      static _GLIBCXX_USE_CONSTEXPR bool is_iec559 = false;
+      static _GLIBCXX_USE_CONSTEXPR bool is_bounded = true;
+      static _GLIBCXX_USE_CONSTEXPR bool is_modulo = false;
+
+      static _GLIBCXX_USE_CONSTEXPR bool traps = __glibcxx_integral_traps;
+      static _GLIBCXX_USE_CONSTEXPR bool tinyness_before = false;
+      static _GLIBCXX_USE_CONSTEXPR float_round_style round_style
+       = round_toward_zero;
+    };
+
+  /// numeric_limits<unsigned short> specialization.
+  template<>
+    struct numeric_limits<unsigned short>
+    {
+      static _GLIBCXX_USE_CONSTEXPR bool is_specialized = true;
+
+      static _GLIBCXX_CONSTEXPR unsigned short
+      min() _GLIBCXX_USE_NOEXCEPT { return 0; }
+
+      static _GLIBCXX_CONSTEXPR unsigned short
+      max() _GLIBCXX_USE_NOEXCEPT { return __SHRT_MAX__ * 2U + 1; }
+
+#if __cplusplus >= 201103L
+      static constexpr unsigned short
+      lowest() noexcept { return min(); }
+#endif
+
+      static _GLIBCXX_USE_CONSTEXPR int digits
+       = __glibcxx_digits (unsigned short);
+      static _GLIBCXX_USE_CONSTEXPR int digits10
+       = __glibcxx_digits10 (unsigned short);
+#if __cplusplus >= 201103L
+      static constexpr int max_digits10 = 0;
+#endif
+      static _GLIBCXX_USE_CONSTEXPR bool is_signed = false;
+      static _GLIBCXX_USE_CONSTEXPR bool is_integer = true;
+      static _GLIBCXX_USE_CONSTEXPR bool is_exact = true;
+      static _GLIBCXX_USE_CONSTEXPR int radix = 2;
+
+      static _GLIBCXX_CONSTEXPR unsigned short
+      epsilon() _GLIBCXX_USE_NOEXCEPT { return 0; }
+
+      static _GLIBCXX_CONSTEXPR unsigned short
+      round_error() _GLIBCXX_USE_NOEXCEPT { return 0; }
+
+      static _GLIBCXX_USE_CONSTEXPR int min_exponent = 0;
+      static _GLIBCXX_USE_CONSTEXPR int min_exponent10 = 0;
+      static _GLIBCXX_USE_CONSTEXPR int max_exponent = 0;
+      static _GLIBCXX_USE_CONSTEXPR int max_exponent10 = 0;
+
+      static _GLIBCXX_USE_CONSTEXPR bool has_infinity = false;
+      static _GLIBCXX_USE_CONSTEXPR bool has_quiet_NaN = false;
+      static _GLIBCXX_USE_CONSTEXPR bool has_signaling_NaN = false;
+      static _GLIBCXX_USE_CONSTEXPR float_denorm_style has_denorm
+       = denorm_absent;
+      static _GLIBCXX_USE_CONSTEXPR bool has_denorm_loss = false;
+
+      static _GLIBCXX_CONSTEXPR unsigned short
+      infinity() _GLIBCXX_USE_NOEXCEPT
+      { return static_cast<unsigned short>(0); }
+
+      static _GLIBCXX_CONSTEXPR unsigned short
+      quiet_NaN() _GLIBCXX_USE_NOEXCEPT
+      { return static_cast<unsigned short>(0); }
+
+      static _GLIBCXX_CONSTEXPR unsigned short
+      signaling_NaN() _GLIBCXX_USE_NOEXCEPT
+      { return static_cast<unsigned short>(0); }
+
+      static _GLIBCXX_CONSTEXPR unsigned short
+      denorm_min() _GLIBCXX_USE_NOEXCEPT
+      { return static_cast<unsigned short>(0); }
+
+      static _GLIBCXX_USE_CONSTEXPR bool is_iec559 = false;
+      static _GLIBCXX_USE_CONSTEXPR bool is_bounded = true;
+      static _GLIBCXX_USE_CONSTEXPR bool is_modulo = true;
+
+      static _GLIBCXX_USE_CONSTEXPR bool traps = __glibcxx_integral_traps;
+      static _GLIBCXX_USE_CONSTEXPR bool tinyness_before = false;
+      static _GLIBCXX_USE_CONSTEXPR float_round_style round_style
+       = round_toward_zero;
+    };
+
+  /// numeric_limits<int> specialization.
+  template<>
+    struct numeric_limits<int>
+    {
+      static _GLIBCXX_USE_CONSTEXPR bool is_specialized = true;
+
+      static _GLIBCXX_CONSTEXPR int
+      min() _GLIBCXX_USE_NOEXCEPT { return -__INT_MAX__ - 1; }
+
+      static _GLIBCXX_CONSTEXPR int
+      max() _GLIBCXX_USE_NOEXCEPT { return __INT_MAX__; }
+
+#if __cplusplus >= 201103L
+      static constexpr int
+      lowest() noexcept { return min(); }
+#endif
+
+      static _GLIBCXX_USE_CONSTEXPR int digits = __glibcxx_digits (int);
+      static _GLIBCXX_USE_CONSTEXPR int digits10 = __glibcxx_digits10 (int);
+#if __cplusplus >= 201103L
+      static constexpr int max_digits10 = 0;
+#endif
+      static _GLIBCXX_USE_CONSTEXPR bool is_signed = true;
+      static _GLIBCXX_USE_CONSTEXPR bool is_integer = true;
+      static _GLIBCXX_USE_CONSTEXPR bool is_exact = true;
+      static _GLIBCXX_USE_CONSTEXPR int radix = 2;
+
+      static _GLIBCXX_CONSTEXPR int
+      epsilon() _GLIBCXX_USE_NOEXCEPT { return 0; }
+
+      static _GLIBCXX_CONSTEXPR int
+      round_error() _GLIBCXX_USE_NOEXCEPT { return 0; }
+
+      static _GLIBCXX_USE_CONSTEXPR int min_exponent = 0;
+      static _GLIBCXX_USE_CONSTEXPR int min_exponent10 = 0;
+      static _GLIBCXX_USE_CONSTEXPR int max_exponent = 0;
+      static _GLIBCXX_USE_CONSTEXPR int max_exponent10 = 0;
+
+      static _GLIBCXX_USE_CONSTEXPR bool has_infinity = false;
+      static _GLIBCXX_USE_CONSTEXPR bool has_quiet_NaN = false;
+      static _GLIBCXX_USE_CONSTEXPR bool has_signaling_NaN = false;
+      static _GLIBCXX_USE_CONSTEXPR float_denorm_style has_denorm
+       = denorm_absent;
+      static _GLIBCXX_USE_CONSTEXPR bool has_denorm_loss = false;
+
+      static _GLIBCXX_CONSTEXPR int
+      infinity() _GLIBCXX_USE_NOEXCEPT { return static_cast<int>(0); }
+
+      static _GLIBCXX_CONSTEXPR int
+      quiet_NaN() _GLIBCXX_USE_NOEXCEPT { return static_cast<int>(0); }
+
+      static _GLIBCXX_CONSTEXPR int
+      signaling_NaN() _GLIBCXX_USE_NOEXCEPT { return static_cast<int>(0); }
+
+      static _GLIBCXX_CONSTEXPR int
+      denorm_min() _GLIBCXX_USE_NOEXCEPT { return static_cast<int>(0); }
+
+      static _GLIBCXX_USE_CONSTEXPR bool is_iec559 = false;
+      static _GLIBCXX_USE_CONSTEXPR bool is_bounded = true;
+      static _GLIBCXX_USE_CONSTEXPR bool is_modulo = false;
+
+      static _GLIBCXX_USE_CONSTEXPR bool traps = __glibcxx_integral_traps;
+      static _GLIBCXX_USE_CONSTEXPR bool tinyness_before = false;
+      static _GLIBCXX_USE_CONSTEXPR float_round_style round_style
+       = round_toward_zero;
+    };
+
+  /// numeric_limits<unsigned int> specialization.
+  template<>
+    struct numeric_limits<unsigned int>
+    {
+      static _GLIBCXX_USE_CONSTEXPR bool is_specialized = true;
+
+      static _GLIBCXX_CONSTEXPR unsigned int
+      min() _GLIBCXX_USE_NOEXCEPT { return 0; }
+
+      static _GLIBCXX_CONSTEXPR unsigned int
+      max() _GLIBCXX_USE_NOEXCEPT { return __INT_MAX__ * 2U + 1; }
+
+#if __cplusplus >= 201103L
+      static constexpr unsigned int
+      lowest() noexcept { return min(); }
+#endif
+
+      static _GLIBCXX_USE_CONSTEXPR int digits
+       = __glibcxx_digits (unsigned int);
+      static _GLIBCXX_USE_CONSTEXPR int digits10
+       = __glibcxx_digits10 (unsigned int);
+#if __cplusplus >= 201103L
+      static constexpr int max_digits10 = 0;
+#endif
+      static _GLIBCXX_USE_CONSTEXPR bool is_signed = false;
+      static _GLIBCXX_USE_CONSTEXPR bool is_integer = true;
+      static _GLIBCXX_USE_CONSTEXPR bool is_exact = true;
+      static _GLIBCXX_USE_CONSTEXPR int radix = 2;
+
+      static _GLIBCXX_CONSTEXPR unsigned int
+      epsilon() _GLIBCXX_USE_NOEXCEPT { return 0; }
+
+      static _GLIBCXX_CONSTEXPR unsigned int
+      round_error() _GLIBCXX_USE_NOEXCEPT { return 0; }
+
+      static _GLIBCXX_USE_CONSTEXPR int min_exponent = 0;
+      static _GLIBCXX_USE_CONSTEXPR int min_exponent10 = 0;
+      static _GLIBCXX_USE_CONSTEXPR int max_exponent = 0;
+      static _GLIBCXX_USE_CONSTEXPR int max_exponent10 = 0;
+
+      static _GLIBCXX_USE_CONSTEXPR bool has_infinity = false;
+      static _GLIBCXX_USE_CONSTEXPR bool has_quiet_NaN = false;
+      static _GLIBCXX_USE_CONSTEXPR bool has_signaling_NaN = false;
+      static _GLIBCXX_USE_CONSTEXPR float_denorm_style has_denorm
+       = denorm_absent;
+      static _GLIBCXX_USE_CONSTEXPR bool has_denorm_loss = false;
+
+      static _GLIBCXX_CONSTEXPR unsigned int
+      infinity() _GLIBCXX_USE_NOEXCEPT { return static_cast<unsigned int>(0); }
+
+      static _GLIBCXX_CONSTEXPR unsigned int
+      quiet_NaN() _GLIBCXX_USE_NOEXCEPT
+      { return static_cast<unsigned int>(0); }
+
+      static _GLIBCXX_CONSTEXPR unsigned int
+      signaling_NaN() _GLIBCXX_USE_NOEXCEPT
+      { return static_cast<unsigned int>(0); }
+
+      static _GLIBCXX_CONSTEXPR unsigned int
+      denorm_min() _GLIBCXX_USE_NOEXCEPT
+      { return static_cast<unsigned int>(0); }
+
+      static _GLIBCXX_USE_CONSTEXPR bool is_iec559 = false;
+      static _GLIBCXX_USE_CONSTEXPR bool is_bounded = true;
+      static _GLIBCXX_USE_CONSTEXPR bool is_modulo = true;
+
+      static _GLIBCXX_USE_CONSTEXPR bool traps = __glibcxx_integral_traps;
+      static _GLIBCXX_USE_CONSTEXPR bool tinyness_before = false;
+      static _GLIBCXX_USE_CONSTEXPR float_round_style round_style
+       = round_toward_zero;
+    };
+
+  /// numeric_limits<long> specialization.
+  template<>
+    struct numeric_limits<long>
+    {
+      static _GLIBCXX_USE_CONSTEXPR bool is_specialized = true;
+
+      static _GLIBCXX_CONSTEXPR long
+      min() _GLIBCXX_USE_NOEXCEPT { return -__LONG_MAX__ - 1; }
+
+      static _GLIBCXX_CONSTEXPR long
+      max() _GLIBCXX_USE_NOEXCEPT { return __LONG_MAX__; }
+
+#if __cplusplus >= 201103L
+      static constexpr long
+      lowest() noexcept { return min(); }
+#endif
+
+      static _GLIBCXX_USE_CONSTEXPR int digits = __glibcxx_digits (long);
+      static _GLIBCXX_USE_CONSTEXPR int digits10 = __glibcxx_digits10 (long);
+#if __cplusplus >= 201103L
+      static constexpr int max_digits10 = 0;
+#endif
+      static _GLIBCXX_USE_CONSTEXPR bool is_signed = true;
+      static _GLIBCXX_USE_CONSTEXPR bool is_integer = true;
+      static _GLIBCXX_USE_CONSTEXPR bool is_exact = true;
+      static _GLIBCXX_USE_CONSTEXPR int radix = 2;
+
+      static _GLIBCXX_CONSTEXPR long
+      epsilon() _GLIBCXX_USE_NOEXCEPT { return 0; }
+
+      static _GLIBCXX_CONSTEXPR long
+      round_error() _GLIBCXX_USE_NOEXCEPT { return 0; }
+
+      static _GLIBCXX_USE_CONSTEXPR int min_exponent = 0;
+      static _GLIBCXX_USE_CONSTEXPR int min_exponent10 = 0;
+      static _GLIBCXX_USE_CONSTEXPR int max_exponent = 0;
+      static _GLIBCXX_USE_CONSTEXPR int max_exponent10 = 0;
+
+      static _GLIBCXX_USE_CONSTEXPR bool has_infinity = false;
+      static _GLIBCXX_USE_CONSTEXPR bool has_quiet_NaN = false;
+      static _GLIBCXX_USE_CONSTEXPR bool has_signaling_NaN = false;
+      static _GLIBCXX_USE_CONSTEXPR float_denorm_style has_denorm
+       = denorm_absent;
+      static _GLIBCXX_USE_CONSTEXPR bool has_denorm_loss = false;
+
+      static _GLIBCXX_CONSTEXPR long
+      infinity() _GLIBCXX_USE_NOEXCEPT { return static_cast<long>(0); }
+
+      static _GLIBCXX_CONSTEXPR long
+      quiet_NaN() _GLIBCXX_USE_NOEXCEPT { return static_cast<long>(0); }
+
+      static _GLIBCXX_CONSTEXPR long
+      signaling_NaN() _GLIBCXX_USE_NOEXCEPT { return static_cast<long>(0); }
+
+      static _GLIBCXX_CONSTEXPR long
+      denorm_min() _GLIBCXX_USE_NOEXCEPT { return static_cast<long>(0); }
+
+      static _GLIBCXX_USE_CONSTEXPR bool is_iec559 = false;
+      static _GLIBCXX_USE_CONSTEXPR bool is_bounded = true;
+      static _GLIBCXX_USE_CONSTEXPR bool is_modulo = false;
+
+      static _GLIBCXX_USE_CONSTEXPR bool traps = __glibcxx_integral_traps;
+      static _GLIBCXX_USE_CONSTEXPR bool tinyness_before = false;
+      static _GLIBCXX_USE_CONSTEXPR float_round_style round_style
+       = round_toward_zero;
+    };
+
+  /// numeric_limits<unsigned long> specialization.
+  template<>
+    struct numeric_limits<unsigned long>
+    {
+      static _GLIBCXX_USE_CONSTEXPR bool is_specialized = true;
+
+      static _GLIBCXX_CONSTEXPR unsigned long
+      min() _GLIBCXX_USE_NOEXCEPT { return 0; }
+
+      static _GLIBCXX_CONSTEXPR unsigned long
+      max() _GLIBCXX_USE_NOEXCEPT { return __LONG_MAX__ * 2UL + 1; }
+
+#if __cplusplus >= 201103L
+      static constexpr unsigned long
+      lowest() noexcept { return min(); }
+#endif
+
+      static _GLIBCXX_USE_CONSTEXPR int digits
+       = __glibcxx_digits (unsigned long);
+      static _GLIBCXX_USE_CONSTEXPR int digits10
+       = __glibcxx_digits10 (unsigned long);
+#if __cplusplus >= 201103L
+      static constexpr int max_digits10 = 0;
+#endif
+      static _GLIBCXX_USE_CONSTEXPR bool is_signed = false;
+      static _GLIBCXX_USE_CONSTEXPR bool is_integer = true;
+      static _GLIBCXX_USE_CONSTEXPR bool is_exact = true;
+      static _GLIBCXX_USE_CONSTEXPR int radix = 2;
+
+      static _GLIBCXX_CONSTEXPR unsigned long
+      epsilon() _GLIBCXX_USE_NOEXCEPT { return 0; }
+
+      static _GLIBCXX_CONSTEXPR unsigned long
+      round_error() _GLIBCXX_USE_NOEXCEPT { return 0; }
+
+      static _GLIBCXX_USE_CONSTEXPR int min_exponent = 0;
+      static _GLIBCXX_USE_CONSTEXPR int min_exponent10 = 0;
+      static _GLIBCXX_USE_CONSTEXPR int max_exponent = 0;
+      static _GLIBCXX_USE_CONSTEXPR int max_exponent10 = 0;
+
+      static _GLIBCXX_USE_CONSTEXPR bool has_infinity = false;
+      static _GLIBCXX_USE_CONSTEXPR bool has_quiet_NaN = false;
+      static _GLIBCXX_USE_CONSTEXPR bool has_signaling_NaN = false;
+      static _GLIBCXX_USE_CONSTEXPR float_denorm_style has_denorm
+       = denorm_absent;
+      static _GLIBCXX_USE_CONSTEXPR bool has_denorm_loss = false;
+
+      static _GLIBCXX_CONSTEXPR unsigned long
+      infinity() _GLIBCXX_USE_NOEXCEPT
+      { return static_cast<unsigned long>(0); }
+
+      static _GLIBCXX_CONSTEXPR unsigned long
+      quiet_NaN() _GLIBCXX_USE_NOEXCEPT
+      { return static_cast<unsigned long>(0); }
+
+      static _GLIBCXX_CONSTEXPR unsigned long
+      signaling_NaN() _GLIBCXX_USE_NOEXCEPT
+      { return static_cast<unsigned long>(0); }
+
+      static _GLIBCXX_CONSTEXPR unsigned long
+      denorm_min() _GLIBCXX_USE_NOEXCEPT
+      { return static_cast<unsigned long>(0); }
+
+      static _GLIBCXX_USE_CONSTEXPR bool is_iec559 = false;
+      static _GLIBCXX_USE_CONSTEXPR bool is_bounded = true;
+      static _GLIBCXX_USE_CONSTEXPR bool is_modulo = true;
+
+      static _GLIBCXX_USE_CONSTEXPR bool traps = __glibcxx_integral_traps;
+      static _GLIBCXX_USE_CONSTEXPR bool tinyness_before = false;
+      static _GLIBCXX_USE_CONSTEXPR float_round_style round_style
+       = round_toward_zero;
+    };
+
+  /// numeric_limits<long long> specialization.
+  template<>
+    struct numeric_limits<long long>
+    {
+      static _GLIBCXX_USE_CONSTEXPR bool is_specialized = true;
+
+      static _GLIBCXX_CONSTEXPR long long
+      min() _GLIBCXX_USE_NOEXCEPT { return -__LONG_LONG_MAX__ - 1; }
+
+      static _GLIBCXX_CONSTEXPR long long
+      max() _GLIBCXX_USE_NOEXCEPT { return __LONG_LONG_MAX__; }
+
+#if __cplusplus >= 201103L
+      static constexpr long long
+      lowest() noexcept { return min(); }
+#endif
+
+      static _GLIBCXX_USE_CONSTEXPR int digits
+       = __glibcxx_digits (long long);
+      static _GLIBCXX_USE_CONSTEXPR int digits10
+       = __glibcxx_digits10 (long long);
+#if __cplusplus >= 201103L
+      static constexpr int max_digits10 = 0;
+#endif
+      static _GLIBCXX_USE_CONSTEXPR bool is_signed = true;
+      static _GLIBCXX_USE_CONSTEXPR bool is_integer = true;
+      static _GLIBCXX_USE_CONSTEXPR bool is_exact = true;
+      static _GLIBCXX_USE_CONSTEXPR int radix = 2;
+
+      static _GLIBCXX_CONSTEXPR long long
+      epsilon() _GLIBCXX_USE_NOEXCEPT { return 0; }
+
+      static _GLIBCXX_CONSTEXPR long long
+      round_error() _GLIBCXX_USE_NOEXCEPT { return 0; }
+
+      static _GLIBCXX_USE_CONSTEXPR int min_exponent = 0;
+      static _GLIBCXX_USE_CONSTEXPR int min_exponent10 = 0;
+      static _GLIBCXX_USE_CONSTEXPR int max_exponent = 0;
+      static _GLIBCXX_USE_CONSTEXPR int max_exponent10 = 0;
+
+      static _GLIBCXX_USE_CONSTEXPR bool has_infinity = false;
+      static _GLIBCXX_USE_CONSTEXPR bool has_quiet_NaN = false;
+      static _GLIBCXX_USE_CONSTEXPR bool has_signaling_NaN = false;
+      static _GLIBCXX_USE_CONSTEXPR float_denorm_style has_denorm
+       = denorm_absent;
+      static _GLIBCXX_USE_CONSTEXPR bool has_denorm_loss = false;
+
+      static _GLIBCXX_CONSTEXPR long long
+      infinity() _GLIBCXX_USE_NOEXCEPT { return static_cast<long long>(0); }
+
+      static _GLIBCXX_CONSTEXPR long long
+      quiet_NaN() _GLIBCXX_USE_NOEXCEPT { return static_cast<long long>(0); }
+
+      static _GLIBCXX_CONSTEXPR long long
+      signaling_NaN() _GLIBCXX_USE_NOEXCEPT
+      { return static_cast<long long>(0); }
+
+      static _GLIBCXX_CONSTEXPR long long
+      denorm_min() _GLIBCXX_USE_NOEXCEPT { return static_cast<long long>(0); }
+
+      static _GLIBCXX_USE_CONSTEXPR bool is_iec559 = false;
+      static _GLIBCXX_USE_CONSTEXPR bool is_bounded = true;
+      static _GLIBCXX_USE_CONSTEXPR bool is_modulo = false;
+
+      static _GLIBCXX_USE_CONSTEXPR bool traps = __glibcxx_integral_traps;
+      static _GLIBCXX_USE_CONSTEXPR bool tinyness_before = false;
+      static _GLIBCXX_USE_CONSTEXPR float_round_style round_style
+       = round_toward_zero;
+    };
+
+  /// numeric_limits<unsigned long long> specialization.
+  template<>
+    struct numeric_limits<unsigned long long>
+    {
+      static _GLIBCXX_USE_CONSTEXPR bool is_specialized = true;
+
+      static _GLIBCXX_CONSTEXPR unsigned long long
+      min() _GLIBCXX_USE_NOEXCEPT { return 0; }
+
+      static _GLIBCXX_CONSTEXPR unsigned long long
+      max() _GLIBCXX_USE_NOEXCEPT { return __LONG_LONG_MAX__ * 2ULL + 1; }
+
+#if __cplusplus >= 201103L
+      static constexpr unsigned long long
+      lowest() noexcept { return min(); }
+#endif
+
+      static _GLIBCXX_USE_CONSTEXPR int digits
+       = __glibcxx_digits (unsigned long long);
+      static _GLIBCXX_USE_CONSTEXPR int digits10
+       = __glibcxx_digits10 (unsigned long long);
+#if __cplusplus >= 201103L
+      static constexpr int max_digits10 = 0;
+#endif
+      static _GLIBCXX_USE_CONSTEXPR bool is_signed = false;
+      static _GLIBCXX_USE_CONSTEXPR bool is_integer = true;
+      static _GLIBCXX_USE_CONSTEXPR bool is_exact = true;
+      static _GLIBCXX_USE_CONSTEXPR int radix = 2;
+
+      static _GLIBCXX_CONSTEXPR unsigned long long
+      epsilon() _GLIBCXX_USE_NOEXCEPT { return 0; }
+
+      static _GLIBCXX_CONSTEXPR unsigned long long
+      round_error() _GLIBCXX_USE_NOEXCEPT { return 0; }
+
+      static _GLIBCXX_USE_CONSTEXPR int min_exponent = 0;
+      static _GLIBCXX_USE_CONSTEXPR int min_exponent10 = 0;
+      static _GLIBCXX_USE_CONSTEXPR int max_exponent = 0;
+      static _GLIBCXX_USE_CONSTEXPR int max_exponent10 = 0;
+
+      static _GLIBCXX_USE_CONSTEXPR bool has_infinity = false;
+      static _GLIBCXX_USE_CONSTEXPR bool has_quiet_NaN = false;
+      static _GLIBCXX_USE_CONSTEXPR bool has_signaling_NaN = false;
+      static _GLIBCXX_USE_CONSTEXPR float_denorm_style has_denorm
+       = denorm_absent;
+      static _GLIBCXX_USE_CONSTEXPR bool has_denorm_loss = false;
+
+      static _GLIBCXX_CONSTEXPR unsigned long long
+      infinity() _GLIBCXX_USE_NOEXCEPT
+      { return static_cast<unsigned long long>(0); }
+
+      static _GLIBCXX_CONSTEXPR unsigned long long
+      quiet_NaN() _GLIBCXX_USE_NOEXCEPT
+      { return static_cast<unsigned long long>(0); }
+
+      static _GLIBCXX_CONSTEXPR unsigned long long
+      signaling_NaN() _GLIBCXX_USE_NOEXCEPT
+      { return static_cast<unsigned long long>(0); }
+
+      static _GLIBCXX_CONSTEXPR unsigned long long
+      denorm_min() _GLIBCXX_USE_NOEXCEPT
+      { return static_cast<unsigned long long>(0); }
+
+      static _GLIBCXX_USE_CONSTEXPR bool is_iec559 = false;
+      static _GLIBCXX_USE_CONSTEXPR bool is_bounded = true;
+      static _GLIBCXX_USE_CONSTEXPR bool is_modulo = true;
+
+      static _GLIBCXX_USE_CONSTEXPR bool traps = __glibcxx_integral_traps;
+      static _GLIBCXX_USE_CONSTEXPR bool tinyness_before = false;
+      static _GLIBCXX_USE_CONSTEXPR float_round_style round_style
+       = round_toward_zero;
+    };
+
+#define __INT_N(TYPE, BITSIZE, EXT, UEXT)				\
+  __extension__								\
+  template<>								\
+    struct numeric_limits<TYPE>						\
+    {									\
+      static _GLIBCXX_USE_CONSTEXPR bool is_specialized = true;		\
+									\
+      static _GLIBCXX_CONSTEXPR TYPE					\
+      min() _GLIBCXX_USE_NOEXCEPT { return __glibcxx_min_b (TYPE, BITSIZE); } \
+									\
+      static _GLIBCXX_CONSTEXPR TYPE					\
+      max() _GLIBCXX_USE_NOEXCEPT { return __glibcxx_max_b (TYPE, BITSIZE); } \
+									\
+      static _GLIBCXX_USE_CONSTEXPR int digits				\
+	= BITSIZE - 1;							\
+      static _GLIBCXX_USE_CONSTEXPR int digits10			\
+	= (BITSIZE - 1) * 643L / 2136;					\
+									\
+      static _GLIBCXX_USE_CONSTEXPR bool is_signed = true;		\
+      static _GLIBCXX_USE_CONSTEXPR bool is_integer = true;		\
+      static _GLIBCXX_USE_CONSTEXPR bool is_exact = true;		\
+      static _GLIBCXX_USE_CONSTEXPR int radix = 2;			\
+									\
+      static _GLIBCXX_CONSTEXPR TYPE					\
+      epsilon() _GLIBCXX_USE_NOEXCEPT { return 0; }			\
+									\
+      static _GLIBCXX_CONSTEXPR TYPE 					\
+      round_error() _GLIBCXX_USE_NOEXCEPT { return 0; }			\
+									\
+      EXT								\
+									\
+      static _GLIBCXX_USE_CONSTEXPR int min_exponent = 0;		\
+      static _GLIBCXX_USE_CONSTEXPR int min_exponent10 = 0;		\
+      static _GLIBCXX_USE_CONSTEXPR int max_exponent = 0;		\
+      static _GLIBCXX_USE_CONSTEXPR int max_exponent10 = 0;		\
+									\
+      static _GLIBCXX_USE_CONSTEXPR bool has_infinity = false;		\
+      static _GLIBCXX_USE_CONSTEXPR bool has_quiet_NaN = false;		\
+      static _GLIBCXX_USE_CONSTEXPR bool has_signaling_NaN = false;	\
+      static _GLIBCXX_USE_CONSTEXPR float_denorm_style has_denorm	\
+	= denorm_absent;						\
+      static _GLIBCXX_USE_CONSTEXPR bool has_denorm_loss = false;	\
+									\
+      static _GLIBCXX_CONSTEXPR TYPE					\
+      infinity() _GLIBCXX_USE_NOEXCEPT					\
+      { return static_cast<TYPE>(0); }					\
+									\
+      static _GLIBCXX_CONSTEXPR TYPE					\
+      quiet_NaN() _GLIBCXX_USE_NOEXCEPT					\
+      { return static_cast<TYPE>(0); }					\
+									\
+      static _GLIBCXX_CONSTEXPR TYPE					\
+      signaling_NaN() _GLIBCXX_USE_NOEXCEPT				\
+      { return static_cast<TYPE>(0); }					\
+									\
+      static _GLIBCXX_CONSTEXPR TYPE					\
+      denorm_min() _GLIBCXX_USE_NOEXCEPT				\
+      { return static_cast<TYPE>(0); }					\
+									\
+      static _GLIBCXX_USE_CONSTEXPR bool is_iec559 = false; 		\
+      static _GLIBCXX_USE_CONSTEXPR bool is_bounded = true; 		\
+      static _GLIBCXX_USE_CONSTEXPR bool is_modulo = false; 		\
+									\
+      static _GLIBCXX_USE_CONSTEXPR bool traps 				\
+	= __glibcxx_integral_traps; 					\
+      static _GLIBCXX_USE_CONSTEXPR bool tinyness_before = false; 	\
+      static _GLIBCXX_USE_CONSTEXPR float_round_style round_style 	\
+	= round_toward_zero; 						\
+    }; 									\
+									\
+  __extension__								\
+  template<>								\
+    struct numeric_limits<unsigned TYPE>				\
+    {									\
+      static _GLIBCXX_USE_CONSTEXPR bool is_specialized = true;		\
+									\
+      static _GLIBCXX_CONSTEXPR unsigned TYPE				\
+      min() _GLIBCXX_USE_NOEXCEPT { return 0; }				\
+									\
+      static _GLIBCXX_CONSTEXPR unsigned TYPE				\
+      max() _GLIBCXX_USE_NOEXCEPT					\
+      { return  __glibcxx_max_b (unsigned TYPE, BITSIZE); }		\
+									\
+      UEXT								\
+									\
+      static _GLIBCXX_USE_CONSTEXPR int digits				\
+	= BITSIZE;							\
+      static _GLIBCXX_USE_CONSTEXPR int digits10			\
+	= BITSIZE * 643L / 2136; 					\
+      static _GLIBCXX_USE_CONSTEXPR bool is_signed = false;		\
+      static _GLIBCXX_USE_CONSTEXPR bool is_integer = true;		\
+      static _GLIBCXX_USE_CONSTEXPR bool is_exact = true;		\
+      static _GLIBCXX_USE_CONSTEXPR int radix = 2;			\
+									\
+      static _GLIBCXX_CONSTEXPR unsigned TYPE 				\
+      epsilon() _GLIBCXX_USE_NOEXCEPT { return 0; }			\
+									\
+      static _GLIBCXX_CONSTEXPR unsigned TYPE				\
+      round_error() _GLIBCXX_USE_NOEXCEPT { return 0; }			\
+									\
+      static _GLIBCXX_USE_CONSTEXPR int min_exponent = 0;		\
+      static _GLIBCXX_USE_CONSTEXPR int min_exponent10 = 0;		\
+      static _GLIBCXX_USE_CONSTEXPR int max_exponent = 0; 		\
+      static _GLIBCXX_USE_CONSTEXPR int max_exponent10 = 0;		\
+									\
+      static _GLIBCXX_USE_CONSTEXPR bool has_infinity = false;		\
+      static _GLIBCXX_USE_CONSTEXPR bool has_quiet_NaN = false;		\
+      static _GLIBCXX_USE_CONSTEXPR bool has_signaling_NaN = false;	\
+      static _GLIBCXX_USE_CONSTEXPR float_denorm_style has_denorm	\
+       = denorm_absent; 						\
+      static _GLIBCXX_USE_CONSTEXPR bool has_denorm_loss = false;	\
+									\
+      static _GLIBCXX_CONSTEXPR unsigned TYPE 				\
+      infinity() _GLIBCXX_USE_NOEXCEPT 					\
+      { return static_cast<unsigned TYPE>(0); }				\
+									\
+      static _GLIBCXX_CONSTEXPR unsigned TYPE				\
+      quiet_NaN() _GLIBCXX_USE_NOEXCEPT 				\
+      { return static_cast<unsigned TYPE>(0); }				\
+									\
+      static _GLIBCXX_CONSTEXPR unsigned TYPE				\
+      signaling_NaN() _GLIBCXX_USE_NOEXCEPT				\
+      { return static_cast<unsigned TYPE>(0); }				\
+									\
+      static _GLIBCXX_CONSTEXPR unsigned TYPE 				\
+      denorm_min() _GLIBCXX_USE_NOEXCEPT				\
+      { return static_cast<unsigned TYPE>(0); }				\
+									\
+      static _GLIBCXX_USE_CONSTEXPR bool is_iec559 = false;		\
+      static _GLIBCXX_USE_CONSTEXPR bool is_bounded = true;		\
+      static _GLIBCXX_USE_CONSTEXPR bool is_modulo = true;		\
+									\
+      static _GLIBCXX_USE_CONSTEXPR bool traps = __glibcxx_integral_traps; \
+      static _GLIBCXX_USE_CONSTEXPR bool tinyness_before = false;	\
+      static _GLIBCXX_USE_CONSTEXPR float_round_style round_style	\
+	= round_toward_zero;						\
+    };
+
+#if __cplusplus >= 201103L
+
+#define __INT_N_201103(TYPE)						\
+      static constexpr TYPE 						\
+      lowest() noexcept { return min(); }				\
+      static constexpr int max_digits10 = 0;
+
+#define __INT_N_U201103(TYPE)						\
+      static constexpr unsigned TYPE  					\
+      lowest() noexcept { return min(); }				\
+      static constexpr int max_digits10 = 0;
+
+#else
+#define __INT_N_201103(TYPE)
+#define __INT_N_U201103(TYPE)
+#endif
+
+#if !defined(__STRICT_ANSI__)
+#ifdef __GLIBCXX_TYPE_INT_N_0
+  __INT_N(__GLIBCXX_TYPE_INT_N_0, __GLIBCXX_BITSIZE_INT_N_0,
+	  __INT_N_201103 (__GLIBCXX_TYPE_INT_N_0),
+	  __INT_N_U201103 (__GLIBCXX_TYPE_INT_N_0))
+#endif
+#ifdef __GLIBCXX_TYPE_INT_N_1
+  __INT_N (__GLIBCXX_TYPE_INT_N_1, __GLIBCXX_BITSIZE_INT_N_1,
+	  __INT_N_201103 (__GLIBCXX_TYPE_INT_N_1),
+	  __INT_N_U201103 (__GLIBCXX_TYPE_INT_N_1))
+#endif
+#ifdef __GLIBCXX_TYPE_INT_N_2
+  __INT_N (__GLIBCXX_TYPE_INT_N_2, __GLIBCXX_BITSIZE_INT_N_2,
+	  __INT_N_201103 (__GLIBCXX_TYPE_INT_N_2),
+	  __INT_N_U201103 (__GLIBCXX_TYPE_INT_N_2))
+#endif
+#ifdef __GLIBCXX_TYPE_INT_N_3
+  __INT_N (__GLIBCXX_TYPE_INT_N_3, __GLIBCXX_BITSIZE_INT_N_3,
+	  __INT_N_201103 (__GLIBCXX_TYPE_INT_N_3),
+	  __INT_N_U201103 (__GLIBCXX_TYPE_INT_N_3))
+#endif
+
+#elif defined __STRICT_ANSI__ && defined __SIZEOF_INT128__
+  __INT_N(__int128, 128,
+	  __INT_N_201103 (__int128),
+	  __INT_N_U201103 (__int128))
+#endif
+
+#undef __INT_N
+#undef __INT_N_201103
+#undef __INT_N_U201103
+
+
+  /// numeric_limits<float> specialization.
+  template<>
+    struct numeric_limits<float>
+    {
+      static _GLIBCXX_USE_CONSTEXPR bool is_specialized = true;
+
+      static _GLIBCXX_CONSTEXPR float
+      min() _GLIBCXX_USE_NOEXCEPT { return __FLT_MIN__; }
+
+      static _GLIBCXX_CONSTEXPR float
+      max() _GLIBCXX_USE_NOEXCEPT { return __FLT_MAX__; }
+
+#if __cplusplus >= 201103L
+      static constexpr float
+      lowest() noexcept { return -__FLT_MAX__; }
+#endif
+
+      static _GLIBCXX_USE_CONSTEXPR int digits = __FLT_MANT_DIG__;
+      static _GLIBCXX_USE_CONSTEXPR int digits10 = __FLT_DIG__;
+#if __cplusplus >= 201103L
+      static constexpr int max_digits10
+	 = __glibcxx_max_digits10 (__FLT_MANT_DIG__);
+#endif
+      static _GLIBCXX_USE_CONSTEXPR bool is_signed = true;
+      static _GLIBCXX_USE_CONSTEXPR bool is_integer = false;
+      static _GLIBCXX_USE_CONSTEXPR bool is_exact = false;
+      static _GLIBCXX_USE_CONSTEXPR int radix = __FLT_RADIX__;
+
+      static _GLIBCXX_CONSTEXPR float
+      epsilon() _GLIBCXX_USE_NOEXCEPT { return __FLT_EPSILON__; }
+
+      static _GLIBCXX_CONSTEXPR float
+      round_error() _GLIBCXX_USE_NOEXCEPT { return 0.5F; }
+
+      static _GLIBCXX_USE_CONSTEXPR int min_exponent = __FLT_MIN_EXP__;
+      static _GLIBCXX_USE_CONSTEXPR int min_exponent10 = __FLT_MIN_10_EXP__;
+      static _GLIBCXX_USE_CONSTEXPR int max_exponent = __FLT_MAX_EXP__;
+      static _GLIBCXX_USE_CONSTEXPR int max_exponent10 = __FLT_MAX_10_EXP__;
+
+      static _GLIBCXX_USE_CONSTEXPR bool has_infinity = __FLT_HAS_INFINITY__;
+      static _GLIBCXX_USE_CONSTEXPR bool has_quiet_NaN = __FLT_HAS_QUIET_NAN__;
+      static _GLIBCXX_USE_CONSTEXPR bool has_signaling_NaN = has_quiet_NaN;
+      static _GLIBCXX_USE_CONSTEXPR float_denorm_style has_denorm
+	= bool(__FLT_HAS_DENORM__) ? denorm_present : denorm_absent;
+      static _GLIBCXX_USE_CONSTEXPR bool has_denorm_loss
+       = __glibcxx_float_has_denorm_loss;
+
+      static _GLIBCXX_CONSTEXPR float
+      infinity() _GLIBCXX_USE_NOEXCEPT { return __builtin_huge_valf(); }
+
+      static _GLIBCXX_CONSTEXPR float
+      quiet_NaN() _GLIBCXX_USE_NOEXCEPT { return __builtin_nanf(""); }
+
+      static _GLIBCXX_CONSTEXPR float
+      signaling_NaN() _GLIBCXX_USE_NOEXCEPT { return __builtin_nansf(""); }
+
+      static _GLIBCXX_CONSTEXPR float
+      denorm_min() _GLIBCXX_USE_NOEXCEPT { return __FLT_DENORM_MIN__; }
+
+      static _GLIBCXX_USE_CONSTEXPR bool is_iec559
+	= has_infinity && has_quiet_NaN && has_denorm == denorm_present;
+      static _GLIBCXX_USE_CONSTEXPR bool is_bounded = true;
+      static _GLIBCXX_USE_CONSTEXPR bool is_modulo = false;
+
+      static _GLIBCXX_USE_CONSTEXPR bool traps = __glibcxx_float_traps;
+      static _GLIBCXX_USE_CONSTEXPR bool tinyness_before
+       = __glibcxx_float_tinyness_before;
+      static _GLIBCXX_USE_CONSTEXPR float_round_style round_style
+       = round_to_nearest;
+    };
+
+#undef __glibcxx_float_has_denorm_loss
+#undef __glibcxx_float_traps
+#undef __glibcxx_float_tinyness_before
+
+  /// numeric_limits<double> specialization.
+  template<>
+    struct numeric_limits<double>
+    {
+      static _GLIBCXX_USE_CONSTEXPR bool is_specialized = true;
+
+      static _GLIBCXX_CONSTEXPR double
+      min() _GLIBCXX_USE_NOEXCEPT { return __DBL_MIN__; }
+
+      static _GLIBCXX_CONSTEXPR double
+      max() _GLIBCXX_USE_NOEXCEPT { return __DBL_MAX__; }
+
+#if __cplusplus >= 201103L
+      static constexpr double
+      lowest() noexcept { return -__DBL_MAX__; }
+#endif
+
+      static _GLIBCXX_USE_CONSTEXPR int digits = __DBL_MANT_DIG__;
+      static _GLIBCXX_USE_CONSTEXPR int digits10 = __DBL_DIG__;
+#if __cplusplus >= 201103L
+      static constexpr int max_digits10
+	 = __glibcxx_max_digits10 (__DBL_MANT_DIG__);
+#endif
+      static _GLIBCXX_USE_CONSTEXPR bool is_signed = true;
+      static _GLIBCXX_USE_CONSTEXPR bool is_integer = false;
+      static _GLIBCXX_USE_CONSTEXPR bool is_exact = false;
+      static _GLIBCXX_USE_CONSTEXPR int radix = __FLT_RADIX__;
+
+      static _GLIBCXX_CONSTEXPR double
+      epsilon() _GLIBCXX_USE_NOEXCEPT { return __DBL_EPSILON__; }
+
+      static _GLIBCXX_CONSTEXPR double
+      round_error() _GLIBCXX_USE_NOEXCEPT { return 0.5; }
+
+      static _GLIBCXX_USE_CONSTEXPR int min_exponent = __DBL_MIN_EXP__;
+      static _GLIBCXX_USE_CONSTEXPR int min_exponent10 = __DBL_MIN_10_EXP__;
+      static _GLIBCXX_USE_CONSTEXPR int max_exponent = __DBL_MAX_EXP__;
+      static _GLIBCXX_USE_CONSTEXPR int max_exponent10 = __DBL_MAX_10_EXP__;
+
+      static _GLIBCXX_USE_CONSTEXPR bool has_infinity = __DBL_HAS_INFINITY__;
+      static _GLIBCXX_USE_CONSTEXPR bool has_quiet_NaN = __DBL_HAS_QUIET_NAN__;
+      static _GLIBCXX_USE_CONSTEXPR bool has_signaling_NaN = has_quiet_NaN;
+      static _GLIBCXX_USE_CONSTEXPR float_denorm_style has_denorm
+	= bool(__DBL_HAS_DENORM__) ? denorm_present : denorm_absent;
+      static _GLIBCXX_USE_CONSTEXPR bool has_denorm_loss
+        = __glibcxx_double_has_denorm_loss;
+
+      static _GLIBCXX_CONSTEXPR double
+      infinity() _GLIBCXX_USE_NOEXCEPT { return __builtin_huge_val(); }
+
+      static _GLIBCXX_CONSTEXPR double
+      quiet_NaN() _GLIBCXX_USE_NOEXCEPT { return __builtin_nan(""); }
+
+      static _GLIBCXX_CONSTEXPR double
+      signaling_NaN() _GLIBCXX_USE_NOEXCEPT { return __builtin_nans(""); }
+
+      static _GLIBCXX_CONSTEXPR double
+      denorm_min() _GLIBCXX_USE_NOEXCEPT { return __DBL_DENORM_MIN__; }
+
+      static _GLIBCXX_USE_CONSTEXPR bool is_iec559
+	= has_infinity && has_quiet_NaN && has_denorm == denorm_present;
+      static _GLIBCXX_USE_CONSTEXPR bool is_bounded = true;
+      static _GLIBCXX_USE_CONSTEXPR bool is_modulo = false;
+
+      static _GLIBCXX_USE_CONSTEXPR bool traps = __glibcxx_double_traps;
+      static _GLIBCXX_USE_CONSTEXPR bool tinyness_before
+       = __glibcxx_double_tinyness_before;
+      static _GLIBCXX_USE_CONSTEXPR float_round_style round_style
+       = round_to_nearest;
+    };
+
+#undef __glibcxx_double_has_denorm_loss
+#undef __glibcxx_double_traps
+#undef __glibcxx_double_tinyness_before
+
+  /// numeric_limits<long double> specialization.
+  template<>
+    struct numeric_limits<long double>
+    {
+      static _GLIBCXX_USE_CONSTEXPR bool is_specialized = true;
+
+      static _GLIBCXX_CONSTEXPR long double
+      min() _GLIBCXX_USE_NOEXCEPT { return __LDBL_MIN__; }
+
+      static _GLIBCXX_CONSTEXPR long double
+      max() _GLIBCXX_USE_NOEXCEPT { return __LDBL_MAX__; }
+
+#if __cplusplus >= 201103L
+      static constexpr long double
+      lowest() noexcept { return -__LDBL_MAX__; }
+#endif
+
+      static _GLIBCXX_USE_CONSTEXPR int digits = __LDBL_MANT_DIG__;
+      static _GLIBCXX_USE_CONSTEXPR int digits10 = __LDBL_DIG__;
+#if __cplusplus >= 201103L
+      static _GLIBCXX_USE_CONSTEXPR int max_digits10
+	 = __glibcxx_max_digits10 (__LDBL_MANT_DIG__);
+#endif
+      static _GLIBCXX_USE_CONSTEXPR bool is_signed = true;
+      static _GLIBCXX_USE_CONSTEXPR bool is_integer = false;
+      static _GLIBCXX_USE_CONSTEXPR bool is_exact = false;
+      static _GLIBCXX_USE_CONSTEXPR int radix = __FLT_RADIX__;
+
+      static _GLIBCXX_CONSTEXPR long double
+      epsilon() _GLIBCXX_USE_NOEXCEPT { return __LDBL_EPSILON__; }
+
+      static _GLIBCXX_CONSTEXPR long double
+      round_error() _GLIBCXX_USE_NOEXCEPT { return 0.5L; }
+
+      static _GLIBCXX_USE_CONSTEXPR int min_exponent = __LDBL_MIN_EXP__;
+      static _GLIBCXX_USE_CONSTEXPR int min_exponent10 = __LDBL_MIN_10_EXP__;
+      static _GLIBCXX_USE_CONSTEXPR int max_exponent = __LDBL_MAX_EXP__;
+      static _GLIBCXX_USE_CONSTEXPR int max_exponent10 = __LDBL_MAX_10_EXP__;
+
+      static _GLIBCXX_USE_CONSTEXPR bool has_infinity = __LDBL_HAS_INFINITY__;
+      static _GLIBCXX_USE_CONSTEXPR bool has_quiet_NaN = __LDBL_HAS_QUIET_NAN__;
+      static _GLIBCXX_USE_CONSTEXPR bool has_signaling_NaN = has_quiet_NaN;
+      static _GLIBCXX_USE_CONSTEXPR float_denorm_style has_denorm
+	= bool(__LDBL_HAS_DENORM__) ? denorm_present : denorm_absent;
+      static _GLIBCXX_USE_CONSTEXPR bool has_denorm_loss
+	= __glibcxx_long_double_has_denorm_loss;
+
+      static _GLIBCXX_CONSTEXPR long double
+      infinity() _GLIBCXX_USE_NOEXCEPT { return __builtin_huge_vall(); }
+
+      static _GLIBCXX_CONSTEXPR long double
+      quiet_NaN() _GLIBCXX_USE_NOEXCEPT { return __builtin_nanl(""); }
+
+      static _GLIBCXX_CONSTEXPR long double
+      signaling_NaN() _GLIBCXX_USE_NOEXCEPT { return __builtin_nansl(""); }
+
+      static _GLIBCXX_CONSTEXPR long double
+      denorm_min() _GLIBCXX_USE_NOEXCEPT { return __LDBL_DENORM_MIN__; }
+
+      static _GLIBCXX_USE_CONSTEXPR bool is_iec559
+	= has_infinity && has_quiet_NaN && has_denorm == denorm_present;
+      static _GLIBCXX_USE_CONSTEXPR bool is_bounded = true;
+      static _GLIBCXX_USE_CONSTEXPR bool is_modulo = false;
+
+      static _GLIBCXX_USE_CONSTEXPR bool traps = __glibcxx_long_double_traps;
+      static _GLIBCXX_USE_CONSTEXPR bool tinyness_before =
+					 __glibcxx_long_double_tinyness_before;
+      static _GLIBCXX_USE_CONSTEXPR float_round_style round_style =
+						      round_to_nearest;
+    };
+
+#undef __glibcxx_long_double_has_denorm_loss
+#undef __glibcxx_long_double_traps
+#undef __glibcxx_long_double_tinyness_before
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#undef __glibcxx_signed
+#undef __glibcxx_min
+#undef __glibcxx_max
+#undef __glibcxx_digits
+#undef __glibcxx_digits10
+#undef __glibcxx_max_digits10
+
+#endif // _GLIBCXX_NUMERIC_LIMITS
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@limits.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@limits.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@list b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@list
new file mode 100644
index 0000000000000000000000000000000000000000..d7ef94317b19e6dd0a8879c398b14751ff91cd63
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@list
@@ -0,0 +1,109 @@
+// <list> -*- C++ -*-
+
+// Copyright (C) 2001-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/*
+ *
+ * Copyright (c) 1994
+ * Hewlett-Packard Company
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Hewlett-Packard Company makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ *
+ *
+ * Copyright (c) 1996,1997
+ * Silicon Graphics Computer Systems, Inc.
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Silicon Graphics makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ */
+
+/** @file include/list
+ *  This is a Standard C++ Library header.
+ */
+
+#ifndef _GLIBCXX_LIST
+#define _GLIBCXX_LIST 1
+
+#pragma GCC system_header
+
+#include <bits/stl_algobase.h>
+#include <bits/allocator.h>
+#include <bits/range_access.h>
+#include <bits/stl_list.h>
+#include <bits/list.tcc>
+
+#ifdef _GLIBCXX_DEBUG
+# include <debug/list>
+#endif
+
+#if __cplusplus >= 201703L
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+  namespace pmr
+  {
+    template<typename _Tp> class polymorphic_allocator;
+    template<typename _Tp>
+      using list = std::list<_Tp, polymorphic_allocator<_Tp>>;
+  } // namespace pmr
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+#endif // C++17
+
+#if __cplusplus > 201703L
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+#define __cpp_lib_erase_if 202002L
+
+  template<typename _Tp, typename _Alloc, typename _Predicate>
+    inline typename list<_Tp, _Alloc>::size_type
+    erase_if(list<_Tp, _Alloc>& __cont, _Predicate __pred)
+    { return __cont.remove_if(__pred); }
+
+  template<typename _Tp, typename _Alloc, typename _Up>
+    inline typename list<_Tp, _Alloc>::size_type
+    erase(list<_Tp, _Alloc>& __cont, const _Up& __value)
+    {
+      using __elem_type = typename list<_Tp, _Alloc>::value_type;
+      return std::erase_if(__cont, [&](__elem_type& __elem) {
+	  return __elem == __value;
+      });
+    }
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+#endif // C++20
+
+#endif /* _GLIBCXX_LIST */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@list.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@list.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@locale b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@locale
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--- /dev/null
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@@ -0,0 +1,46 @@
+// Locale support -*- C++ -*-
+
+// Copyright (C) 1997-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+//
+// ISO C++ 14882: 22.1  Locales
+//
+
+/** @file include/locale
+ *  This is a Standard C++ Library header.
+ */
+
+#ifndef _GLIBCXX_LOCALE
+#define _GLIBCXX_LOCALE	1
+
+#pragma GCC system_header
+
+#include <bits/localefwd.h>
+#include <bits/locale_classes.h>
+#include <bits/locale_facets.h>
+#include <bits/locale_facets_nonio.h>
+#if __cplusplus >= 201103L
+#  include <bits/locale_conv.h>
+#endif
+
+#endif /* _GLIBCXX_LOCALE */
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@map b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@map
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index 0000000000000000000000000000000000000000..93c956af916654d68b5df98d7a989c62138cef45
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@map
@@ -0,0 +1,117 @@
+// <map> -*- C++ -*-
+
+// Copyright (C) 2001-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/*
+ *
+ * Copyright (c) 1994
+ * Hewlett-Packard Company
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Hewlett-Packard Company makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ *
+ *
+ * Copyright (c) 1996,1997
+ * Silicon Graphics Computer Systems, Inc.
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Silicon Graphics makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ */
+
+/** @file include/map
+ *  This is a Standard C++ Library header.
+ */
+
+#ifndef _GLIBCXX_MAP
+#define _GLIBCXX_MAP 1
+
+#pragma GCC system_header
+
+#include <bits/stl_tree.h>
+#include <bits/stl_map.h>
+#include <bits/stl_multimap.h>
+#include <bits/range_access.h>
+#include <bits/erase_if.h>
+
+#ifdef _GLIBCXX_DEBUG
+# include <debug/map>
+#endif
+
+#if __cplusplus >= 201703L
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+  namespace pmr
+  {
+    template<typename _Tp> class polymorphic_allocator;
+    template<typename _Key, typename _Tp, typename _Cmp = std::less<_Key>>
+      using map
+	= std::map<_Key, _Tp, _Cmp,
+		   polymorphic_allocator<pair<const _Key, _Tp>>>;
+    template<typename _Key, typename _Tp, typename _Cmp = std::less<_Key>>
+      using multimap
+	= std::multimap<_Key, _Tp, _Cmp,
+			polymorphic_allocator<pair<const _Key, _Tp>>>;
+  } // namespace pmr
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+#endif // C++17
+
+#if __cplusplus > 201703L
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+  template<typename _Key, typename _Tp, typename _Compare, typename _Alloc,
+	   typename _Predicate>
+    inline typename map<_Key, _Tp, _Compare, _Alloc>::size_type
+    erase_if(map<_Key, _Tp, _Compare, _Alloc>& __cont, _Predicate __pred)
+    {
+      const _GLIBCXX_STD_C::map<_Key, _Tp, _Compare, _Alloc>&
+	__ucont = __cont;
+      return __detail::__erase_nodes_if(__cont, __ucont, __pred);
+    }
+
+  template<typename _Key, typename _Tp, typename _Compare, typename _Alloc,
+	   typename _Predicate>
+    inline typename multimap<_Key, _Tp, _Compare, _Alloc>::size_type
+    erase_if(multimap<_Key, _Tp, _Compare, _Alloc>& __cont, _Predicate __pred)
+    {
+      const _GLIBCXX_STD_C::multimap<_Key, _Tp, _Compare, _Alloc>&
+	__ucont = __cont;
+      return __detail::__erase_nodes_if(__cont, __ucont, __pred);
+    }
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+#endif // C++20
+
+#endif /* _GLIBCXX_MAP */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@map.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@map.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@memory b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@memory
new file mode 100644
index 0000000000000000000000000000000000000000..481fa42a6188e40a6daf88d5fd53f56feb7e3c50
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@memory
@@ -0,0 +1,151 @@
+// <memory> -*- C++ -*-
+
+// Copyright (C) 2001-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/*
+ * Copyright (c) 1997-1999
+ * Silicon Graphics Computer Systems, Inc.
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Silicon Graphics makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ *
+ */
+
+/** @file include/memory
+ *  This is a Standard C++ Library header.
+ *  @ingroup memory
+ */
+
+#ifndef _GLIBCXX_MEMORY
+#define _GLIBCXX_MEMORY 1
+
+#pragma GCC system_header
+
+/**
+ * @defgroup memory Memory
+ * @ingroup utilities
+ *
+ * Components for memory allocation, deallocation, and management.
+ */
+
+/**
+ * @defgroup pointer_abstractions Pointer Abstractions
+ * @ingroup memory
+ *
+ * Smart pointers, etc.
+ */
+
+#include <bits/stl_algobase.h>
+#include <bits/allocator.h>
+#include <bits/stl_construct.h>
+#include <bits/stl_uninitialized.h>
+#include <bits/stl_tempbuf.h>
+#include <bits/stl_raw_storage_iter.h>
+
+#if __cplusplus >= 201103L
+#  include <type_traits>
+#  include <bits/align.h>
+#  include <bits/uses_allocator.h>
+#  include <bits/alloc_traits.h>
+#  include <debug/debug.h>
+#  include <bits/unique_ptr.h>
+#  include <bits/shared_ptr.h>
+#  include <bits/shared_ptr_atomic.h>
+#endif
+
+#if __cplusplus < 201103L || _GLIBCXX_USE_DEPRECATED
+#  include <backward/auto_ptr.h>
+#endif
+
+#if __cplusplus > 201703L
+#  include <bits/ranges_uninitialized.h>
+#  include <bits/uses_allocator_args.h>
+#endif
+
+#if __cplusplus >= 201103L && __cplusplus <= 202002L
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+/** @defgroup ptr_safety Pointer Safety and Garbage Collection
+ *  @ingroup memory
+ *
+ * Utilities to assist with garbage collection in an implementation
+ * that supports <em>strict pointer safety</em>.
+ * This implementation only supports <em>relaxed pointer safety</em>
+ * and so these functions have no effect.
+ *
+ * C++11 20.6.4 [util.dynamic.safety], Pointer safety
+ *
+ * @{
+ */
+
+/// Constants representing the different types of pointer safety.
+enum class pointer_safety { relaxed, preferred, strict };
+
+/// Inform a garbage collector that an object is still in use.
+inline void
+declare_reachable(void*) { }
+
+/// Unregister an object previously registered with declare_reachable.
+template <typename _Tp>
+  inline _Tp*
+  undeclare_reachable(_Tp* __p) { return __p; }
+
+/// Inform a garbage collector that a region of memory need not be traced.
+inline void
+declare_no_pointers(char*, size_t) { }
+
+/// Unregister a range previously registered with declare_no_pointers.
+inline void
+undeclare_no_pointers(char*, size_t) { }
+
+/// The type of pointer safety supported by the implementation.
+inline pointer_safety
+get_pointer_safety() noexcept { return pointer_safety::relaxed; }
+/// @}
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+#endif // C++11 to C++20
+
+#if __cplusplus >= 201703L
+// Parallel STL algorithms
+# if _PSTL_EXECUTION_POLICIES_DEFINED
+// If <execution> has already been included, pull in implementations
+#  include <pstl/glue_memory_impl.h>
+# else
+// Otherwise just pull in forward declarations
+#  include <pstl/glue_memory_defs.h>
+# endif
+
+// Feature test macro for parallel algorithms
+# define __cpp_lib_parallel_algorithm 201603L
+#endif // C++17
+
+#endif /* _GLIBCXX_MEMORY */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@memory.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@memory.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@mutex b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@mutex
new file mode 100644
index 0000000000000000000000000000000000000000..f500818d9c9ea1d1657ccd895d69825886bb0d9f
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@mutex
@@ -0,0 +1,969 @@
+// <mutex> -*- C++ -*-
+
+// Copyright (C) 2003-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file include/mutex
+ *  This is a Standard C++ Library header.
+ */
+
+#ifndef _GLIBCXX_MUTEX
+#define _GLIBCXX_MUTEX 1
+
+#pragma GCC system_header
+
+#if __cplusplus < 201103L
+# include <bits/c++0x_warning.h>
+#else
+
+#include <tuple>
+#include <exception>
+#include <type_traits>
+#include <system_error>
+#include <bits/chrono.h>
+#include <bits/std_mutex.h>
+#include <bits/unique_lock.h>
+#if ! _GTHREAD_USE_MUTEX_TIMEDLOCK
+# include <condition_variable>
+# include <thread>
+#endif
+#include <ext/atomicity.h>     // __gnu_cxx::__is_single_threaded
+
+#if defined _GLIBCXX_HAS_GTHREADS && ! defined _GLIBCXX_HAVE_TLS
+# include <bits/std_function.h>  // std::function
+#endif
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /**
+   * @addtogroup mutexes
+   * @{
+   */
+
+#ifdef _GLIBCXX_HAS_GTHREADS
+
+  // Common base class for std::recursive_mutex and std::recursive_timed_mutex
+  class __recursive_mutex_base
+  {
+  protected:
+    typedef __gthread_recursive_mutex_t		__native_type;
+
+    __recursive_mutex_base(const __recursive_mutex_base&) = delete;
+    __recursive_mutex_base& operator=(const __recursive_mutex_base&) = delete;
+
+#ifdef __GTHREAD_RECURSIVE_MUTEX_INIT
+    __native_type  _M_mutex = __GTHREAD_RECURSIVE_MUTEX_INIT;
+
+    __recursive_mutex_base() = default;
+#else
+    __native_type  _M_mutex;
+
+    __recursive_mutex_base()
+    {
+      // XXX EAGAIN, ENOMEM, EPERM, EBUSY(may), EINVAL(may)
+      __GTHREAD_RECURSIVE_MUTEX_INIT_FUNCTION(&_M_mutex);
+    }
+
+    ~__recursive_mutex_base()
+    { __gthread_recursive_mutex_destroy(&_M_mutex); }
+#endif
+  };
+
+  /// The standard recursive mutex type.
+  class recursive_mutex : private __recursive_mutex_base
+  {
+  public:
+    typedef __native_type* 			native_handle_type;
+
+    recursive_mutex() = default;
+    ~recursive_mutex() = default;
+
+    recursive_mutex(const recursive_mutex&) = delete;
+    recursive_mutex& operator=(const recursive_mutex&) = delete;
+
+    void
+    lock()
+    {
+      int __e = __gthread_recursive_mutex_lock(&_M_mutex);
+
+      // EINVAL, EAGAIN, EBUSY, EINVAL, EDEADLK(may)
+      if (__e)
+	__throw_system_error(__e);
+    }
+
+    bool
+    try_lock() noexcept
+    {
+      // XXX EINVAL, EAGAIN, EBUSY
+      return !__gthread_recursive_mutex_trylock(&_M_mutex);
+    }
+
+    void
+    unlock()
+    {
+      // XXX EINVAL, EAGAIN, EBUSY
+      __gthread_recursive_mutex_unlock(&_M_mutex);
+    }
+
+    native_handle_type
+    native_handle() noexcept
+    { return &_M_mutex; }
+  };
+
+#if _GTHREAD_USE_MUTEX_TIMEDLOCK
+  template<typename _Derived>
+    class __timed_mutex_impl
+    {
+    protected:
+      template<typename _Rep, typename _Period>
+	bool
+	_M_try_lock_for(const chrono::duration<_Rep, _Period>& __rtime)
+	{
+#if _GLIBCXX_USE_PTHREAD_MUTEX_CLOCKLOCK
+	  using __clock = chrono::steady_clock;
+#else
+	  using __clock = chrono::system_clock;
+#endif
+
+	  auto __rt = chrono::duration_cast<__clock::duration>(__rtime);
+	  if (ratio_greater<__clock::period, _Period>())
+	    ++__rt;
+	  return _M_try_lock_until(__clock::now() + __rt);
+	}
+
+      template<typename _Duration>
+	bool
+	_M_try_lock_until(const chrono::time_point<chrono::system_clock,
+						   _Duration>& __atime)
+	{
+	  auto __s = chrono::time_point_cast<chrono::seconds>(__atime);
+	  auto __ns = chrono::duration_cast<chrono::nanoseconds>(__atime - __s);
+
+	  __gthread_time_t __ts = {
+	    static_cast<std::time_t>(__s.time_since_epoch().count()),
+	    static_cast<long>(__ns.count())
+	  };
+
+	  return static_cast<_Derived*>(this)->_M_timedlock(__ts);
+	}
+
+#ifdef _GLIBCXX_USE_PTHREAD_MUTEX_CLOCKLOCK
+      template<typename _Duration>
+	bool
+	_M_try_lock_until(const chrono::time_point<chrono::steady_clock,
+						   _Duration>& __atime)
+	{
+	  auto __s = chrono::time_point_cast<chrono::seconds>(__atime);
+	  auto __ns = chrono::duration_cast<chrono::nanoseconds>(__atime - __s);
+
+	  __gthread_time_t __ts = {
+	    static_cast<std::time_t>(__s.time_since_epoch().count()),
+	    static_cast<long>(__ns.count())
+	  };
+
+	  return static_cast<_Derived*>(this)->_M_clocklock(CLOCK_MONOTONIC,
+							    __ts);
+	}
+#endif
+
+      template<typename _Clock, typename _Duration>
+	bool
+	_M_try_lock_until(const chrono::time_point<_Clock, _Duration>& __atime)
+	{
+#if __cplusplus > 201703L
+	  static_assert(chrono::is_clock_v<_Clock>);
+#endif
+	  // The user-supplied clock may not tick at the same rate as
+	  // steady_clock, so we must loop in order to guarantee that
+	  // the timeout has expired before returning false.
+	  auto __now = _Clock::now();
+	  do {
+	    auto __rtime = __atime - __now;
+	    if (_M_try_lock_for(__rtime))
+	      return true;
+	    __now = _Clock::now();
+	  } while (__atime > __now);
+	  return false;
+	}
+    };
+
+  /// The standard timed mutex type.
+  class timed_mutex
+  : private __mutex_base, public __timed_mutex_impl<timed_mutex>
+  {
+  public:
+    typedef __native_type* 		  	native_handle_type;
+
+    timed_mutex() = default;
+    ~timed_mutex() = default;
+
+    timed_mutex(const timed_mutex&) = delete;
+    timed_mutex& operator=(const timed_mutex&) = delete;
+
+    void
+    lock()
+    {
+      int __e = __gthread_mutex_lock(&_M_mutex);
+
+      // EINVAL, EAGAIN, EBUSY, EINVAL, EDEADLK(may)
+      if (__e)
+	__throw_system_error(__e);
+    }
+
+    bool
+    try_lock() noexcept
+    {
+      // XXX EINVAL, EAGAIN, EBUSY
+      return !__gthread_mutex_trylock(&_M_mutex);
+    }
+
+    template <class _Rep, class _Period>
+      bool
+      try_lock_for(const chrono::duration<_Rep, _Period>& __rtime)
+      { return _M_try_lock_for(__rtime); }
+
+    template <class _Clock, class _Duration>
+      bool
+      try_lock_until(const chrono::time_point<_Clock, _Duration>& __atime)
+      { return _M_try_lock_until(__atime); }
+
+    void
+    unlock()
+    {
+      // XXX EINVAL, EAGAIN, EBUSY
+      __gthread_mutex_unlock(&_M_mutex);
+    }
+
+    native_handle_type
+    native_handle() noexcept
+    { return &_M_mutex; }
+
+    private:
+      friend class __timed_mutex_impl<timed_mutex>;
+
+      bool
+      _M_timedlock(const __gthread_time_t& __ts)
+      { return !__gthread_mutex_timedlock(&_M_mutex, &__ts); }
+
+#if _GLIBCXX_USE_PTHREAD_MUTEX_CLOCKLOCK
+      bool
+      _M_clocklock(clockid_t clockid, const __gthread_time_t& __ts)
+      { return !pthread_mutex_clocklock(&_M_mutex, clockid, &__ts); }
+#endif
+  };
+
+  /// recursive_timed_mutex
+  class recursive_timed_mutex
+  : private __recursive_mutex_base,
+    public __timed_mutex_impl<recursive_timed_mutex>
+  {
+  public:
+    typedef __native_type* 			native_handle_type;
+
+    recursive_timed_mutex() = default;
+    ~recursive_timed_mutex() = default;
+
+    recursive_timed_mutex(const recursive_timed_mutex&) = delete;
+    recursive_timed_mutex& operator=(const recursive_timed_mutex&) = delete;
+
+    void
+    lock()
+    {
+      int __e = __gthread_recursive_mutex_lock(&_M_mutex);
+
+      // EINVAL, EAGAIN, EBUSY, EINVAL, EDEADLK(may)
+      if (__e)
+	__throw_system_error(__e);
+    }
+
+    bool
+    try_lock() noexcept
+    {
+      // XXX EINVAL, EAGAIN, EBUSY
+      return !__gthread_recursive_mutex_trylock(&_M_mutex);
+    }
+
+    template <class _Rep, class _Period>
+      bool
+      try_lock_for(const chrono::duration<_Rep, _Period>& __rtime)
+      { return _M_try_lock_for(__rtime); }
+
+    template <class _Clock, class _Duration>
+      bool
+      try_lock_until(const chrono::time_point<_Clock, _Duration>& __atime)
+      { return _M_try_lock_until(__atime); }
+
+    void
+    unlock()
+    {
+      // XXX EINVAL, EAGAIN, EBUSY
+      __gthread_recursive_mutex_unlock(&_M_mutex);
+    }
+
+    native_handle_type
+    native_handle() noexcept
+    { return &_M_mutex; }
+
+    private:
+      friend class __timed_mutex_impl<recursive_timed_mutex>;
+
+      bool
+      _M_timedlock(const __gthread_time_t& __ts)
+      { return !__gthread_recursive_mutex_timedlock(&_M_mutex, &__ts); }
+
+#ifdef _GLIBCXX_USE_PTHREAD_MUTEX_CLOCKLOCK
+      bool
+      _M_clocklock(clockid_t clockid, const __gthread_time_t& __ts)
+      { return !pthread_mutex_clocklock(&_M_mutex, clockid, &__ts); }
+#endif
+  };
+
+#else // !_GTHREAD_USE_MUTEX_TIMEDLOCK
+
+  /// timed_mutex
+  class timed_mutex
+  {
+    mutex		_M_mut;
+    condition_variable	_M_cv;
+    bool		_M_locked = false;
+
+  public:
+
+    timed_mutex() = default;
+    ~timed_mutex() { __glibcxx_assert( !_M_locked ); }
+
+    timed_mutex(const timed_mutex&) = delete;
+    timed_mutex& operator=(const timed_mutex&) = delete;
+
+    void
+    lock()
+    {
+      unique_lock<mutex> __lk(_M_mut);
+      _M_cv.wait(__lk, [&]{ return !_M_locked; });
+      _M_locked = true;
+    }
+
+    bool
+    try_lock()
+    {
+      lock_guard<mutex> __lk(_M_mut);
+      if (_M_locked)
+	return false;
+      _M_locked = true;
+      return true;
+    }
+
+    template<typename _Rep, typename _Period>
+      bool
+      try_lock_for(const chrono::duration<_Rep, _Period>& __rtime)
+      {
+	unique_lock<mutex> __lk(_M_mut);
+	if (!_M_cv.wait_for(__lk, __rtime, [&]{ return !_M_locked; }))
+	  return false;
+	_M_locked = true;
+	return true;
+      }
+
+    template<typename _Clock, typename _Duration>
+      bool
+      try_lock_until(const chrono::time_point<_Clock, _Duration>& __atime)
+      {
+	unique_lock<mutex> __lk(_M_mut);
+	if (!_M_cv.wait_until(__lk, __atime, [&]{ return !_M_locked; }))
+	  return false;
+	_M_locked = true;
+	return true;
+      }
+
+    void
+    unlock()
+    {
+      lock_guard<mutex> __lk(_M_mut);
+      __glibcxx_assert( _M_locked );
+      _M_locked = false;
+      _M_cv.notify_one();
+    }
+  };
+
+  /// recursive_timed_mutex
+  class recursive_timed_mutex
+  {
+    mutex		_M_mut;
+    condition_variable	_M_cv;
+    thread::id		_M_owner;
+    unsigned		_M_count = 0;
+
+    // Predicate type that tests whether the current thread can lock a mutex.
+    struct _Can_lock
+    {
+      // Returns true if the mutex is unlocked or is locked by _M_caller.
+      bool
+      operator()() const noexcept
+      { return _M_mx->_M_count == 0 || _M_mx->_M_owner == _M_caller; }
+
+      const recursive_timed_mutex* _M_mx;
+      thread::id _M_caller;
+    };
+
+  public:
+
+    recursive_timed_mutex() = default;
+    ~recursive_timed_mutex() { __glibcxx_assert( _M_count == 0 ); }
+
+    recursive_timed_mutex(const recursive_timed_mutex&) = delete;
+    recursive_timed_mutex& operator=(const recursive_timed_mutex&) = delete;
+
+    void
+    lock()
+    {
+      auto __id = this_thread::get_id();
+      _Can_lock __can_lock{this, __id};
+      unique_lock<mutex> __lk(_M_mut);
+      _M_cv.wait(__lk, __can_lock);
+      if (_M_count == -1u)
+	__throw_system_error(EAGAIN); // [thread.timedmutex.recursive]/3
+      _M_owner = __id;
+      ++_M_count;
+    }
+
+    bool
+    try_lock()
+    {
+      auto __id = this_thread::get_id();
+      _Can_lock __can_lock{this, __id};
+      lock_guard<mutex> __lk(_M_mut);
+      if (!__can_lock())
+	return false;
+      if (_M_count == -1u)
+	return false;
+      _M_owner = __id;
+      ++_M_count;
+      return true;
+    }
+
+    template<typename _Rep, typename _Period>
+      bool
+      try_lock_for(const chrono::duration<_Rep, _Period>& __rtime)
+      {
+	auto __id = this_thread::get_id();
+	_Can_lock __can_lock{this, __id};
+	unique_lock<mutex> __lk(_M_mut);
+	if (!_M_cv.wait_for(__lk, __rtime, __can_lock))
+	  return false;
+	if (_M_count == -1u)
+	  return false;
+	_M_owner = __id;
+	++_M_count;
+	return true;
+      }
+
+    template<typename _Clock, typename _Duration>
+      bool
+      try_lock_until(const chrono::time_point<_Clock, _Duration>& __atime)
+      {
+	auto __id = this_thread::get_id();
+	_Can_lock __can_lock{this, __id};
+	unique_lock<mutex> __lk(_M_mut);
+	if (!_M_cv.wait_until(__lk, __atime, __can_lock))
+	  return false;
+	if (_M_count == -1u)
+	  return false;
+	_M_owner = __id;
+	++_M_count;
+	return true;
+      }
+
+    void
+    unlock()
+    {
+      lock_guard<mutex> __lk(_M_mut);
+      __glibcxx_assert( _M_owner == this_thread::get_id() );
+      __glibcxx_assert( _M_count > 0 );
+      if (--_M_count == 0)
+	{
+	  _M_owner = {};
+	  _M_cv.notify_one();
+	}
+    }
+  };
+
+#endif
+#endif // _GLIBCXX_HAS_GTHREADS
+
+  /// @cond undocumented
+  namespace __detail
+  {
+    // Lock the last lockable, after all previous ones are locked.
+    template<typename _Lockable>
+      inline int
+      __try_lock_impl(_Lockable& __l)
+      {
+	if (unique_lock<_Lockable> __lock{__l, try_to_lock})
+	  {
+	    __lock.release();
+	    return -1;
+	  }
+	else
+	  return 0;
+      }
+
+    // Lock each lockable in turn.
+    // Use iteration if all lockables are the same type, recursion otherwise.
+    template<typename _L0, typename... _Lockables>
+      inline int
+      __try_lock_impl(_L0& __l0, _Lockables&... __lockables)
+      {
+#if __cplusplus >= 201703L
+	if constexpr ((is_same_v<_L0, _Lockables> && ...))
+	  {
+	    constexpr int _Np = 1 + sizeof...(_Lockables);
+	    unique_lock<_L0> __locks[_Np] = {
+		{__l0, defer_lock}, {__lockables, defer_lock}...
+	    };
+	    for (int __i = 0; __i < _Np; ++__i)
+	      {
+		if (!__locks[__i].try_lock())
+		  {
+		    const int __failed = __i;
+		    while (__i--)
+		      __locks[__i].unlock();
+		    return __failed;
+		  }
+	      }
+	    for (auto& __l : __locks)
+	      __l.release();
+	    return -1;
+	  }
+	else
+#endif
+	if (unique_lock<_L0> __lock{__l0, try_to_lock})
+	  {
+	    int __idx = __detail::__try_lock_impl(__lockables...);
+	    if (__idx == -1)
+	      {
+		__lock.release();
+		return -1;
+	      }
+	    return __idx + 1;
+	  }
+	else
+	  return 0;
+      }
+
+  } // namespace __detail
+  /// @endcond
+
+  /** @brief Generic try_lock.
+   *  @param __l1 Meets Lockable requirements (try_lock() may throw).
+   *  @param __l2 Meets Lockable requirements (try_lock() may throw).
+   *  @param __l3 Meets Lockable requirements (try_lock() may throw).
+   *  @return Returns -1 if all try_lock() calls return true. Otherwise returns
+   *          a 0-based index corresponding to the argument that returned false.
+   *  @post Either all arguments are locked, or none will be.
+   *
+   *  Sequentially calls try_lock() on each argument.
+   */
+  template<typename _L1, typename _L2, typename... _L3>
+    inline int
+    try_lock(_L1& __l1, _L2& __l2, _L3&... __l3)
+    {
+      return __detail::__try_lock_impl(__l1, __l2, __l3...);
+    }
+
+  /// @cond undocumented
+  namespace __detail
+  {
+    // This function can recurse up to N levels deep, for N = 1+sizeof...(L1).
+    // On each recursion the lockables are rotated left one position,
+    // e.g. depth 0: l0, l1, l2; depth 1: l1, l2, l0; depth 2: l2, l0, l1.
+    // When a call to l_i.try_lock() fails it recurses/returns to depth=i
+    // so that l_i is the first argument, and then blocks until l_i is locked.
+    template<typename _L0, typename... _L1>
+      void
+      __lock_impl(int& __i, int __depth, _L0& __l0, _L1&... __l1)
+      {
+	while (__i >= __depth)
+	  {
+	    if (__i == __depth)
+	      {
+		int __failed = 1; // index that couldn't be locked
+		{
+		  unique_lock<_L0> __first(__l0);
+		  __failed += __detail::__try_lock_impl(__l1...);
+		  if (!__failed)
+		    {
+		      __i = -1; // finished
+		      __first.release();
+		      return;
+		    }
+		}
+#if defined _GLIBCXX_HAS_GTHREADS && defined _GLIBCXX_USE_SCHED_YIELD
+		__gthread_yield();
+#endif
+		constexpr auto __n = 1 + sizeof...(_L1);
+		__i = (__depth + __failed) % __n;
+	      }
+	    else // rotate left until l_i is first.
+	      __detail::__lock_impl(__i, __depth + 1, __l1..., __l0);
+	  }
+      }
+
+  } // namespace __detail
+  /// @endcond
+
+  /** @brief Generic lock.
+   *  @param __l1 Meets Lockable requirements (try_lock() may throw).
+   *  @param __l2 Meets Lockable requirements (try_lock() may throw).
+   *  @param __l3 Meets Lockable requirements (try_lock() may throw).
+   *  @throw An exception thrown by an argument's lock() or try_lock() member.
+   *  @post All arguments are locked.
+   *
+   *  All arguments are locked via a sequence of calls to lock(), try_lock()
+   *  and unlock().  If this function exits via an exception any locks that
+   *  were obtained will be released.
+   */
+  template<typename _L1, typename _L2, typename... _L3>
+    void
+    lock(_L1& __l1, _L2& __l2, _L3&... __l3)
+    {
+#if __cplusplus >= 201703L
+      if constexpr (is_same_v<_L1, _L2> && (is_same_v<_L1, _L3> && ...))
+	{
+	  constexpr int _Np = 2 + sizeof...(_L3);
+	  unique_lock<_L1> __locks[] = {
+	      {__l1, defer_lock}, {__l2, defer_lock}, {__l3, defer_lock}...
+	  };
+	  int __first = 0;
+	  do {
+	    __locks[__first].lock();
+	    for (int __j = 1; __j < _Np; ++__j)
+	      {
+		const int __idx = (__first + __j) % _Np;
+		if (!__locks[__idx].try_lock())
+		  {
+		    for (int __k = __j; __k != 0; --__k)
+		      __locks[(__first + __k - 1) % _Np].unlock();
+		    __first = __idx;
+		    break;
+		  }
+	      }
+	  } while (!__locks[__first].owns_lock());
+
+	  for (auto& __l : __locks)
+	    __l.release();
+	}
+      else
+#endif
+	{
+	  int __i = 0;
+	  __detail::__lock_impl(__i, 0, __l1, __l2, __l3...);
+	}
+    }
+
+#if __cplusplus >= 201703L
+#define __cpp_lib_scoped_lock 201703L
+  /** @brief A scoped lock type for multiple lockable objects.
+   *
+   * A scoped_lock controls mutex ownership within a scope, releasing
+   * ownership in the destructor.
+   */
+  template<typename... _MutexTypes>
+    class scoped_lock
+    {
+    public:
+      explicit scoped_lock(_MutexTypes&... __m) : _M_devices(std::tie(__m...))
+      { std::lock(__m...); }
+
+      explicit scoped_lock(adopt_lock_t, _MutexTypes&... __m) noexcept
+      : _M_devices(std::tie(__m...))
+      { } // calling thread owns mutex
+
+      ~scoped_lock()
+      { std::apply([](auto&... __m) { (__m.unlock(), ...); }, _M_devices); }
+
+      scoped_lock(const scoped_lock&) = delete;
+      scoped_lock& operator=(const scoped_lock&) = delete;
+
+    private:
+      tuple<_MutexTypes&...> _M_devices;
+    };
+
+  template<>
+    class scoped_lock<>
+    {
+    public:
+      explicit scoped_lock() = default;
+      explicit scoped_lock(adopt_lock_t) noexcept { }
+      ~scoped_lock() = default;
+
+      scoped_lock(const scoped_lock&) = delete;
+      scoped_lock& operator=(const scoped_lock&) = delete;
+    };
+
+  template<typename _Mutex>
+    class scoped_lock<_Mutex>
+    {
+    public:
+      using mutex_type = _Mutex;
+
+      explicit scoped_lock(mutex_type& __m) : _M_device(__m)
+      { _M_device.lock(); }
+
+      explicit scoped_lock(adopt_lock_t, mutex_type& __m) noexcept
+      : _M_device(__m)
+      { } // calling thread owns mutex
+
+      ~scoped_lock()
+      { _M_device.unlock(); }
+
+      scoped_lock(const scoped_lock&) = delete;
+      scoped_lock& operator=(const scoped_lock&) = delete;
+
+    private:
+      mutex_type&  _M_device;
+    };
+#endif // C++17
+
+#ifdef _GLIBCXX_HAS_GTHREADS
+  /// Flag type used by std::call_once
+  struct once_flag
+  {
+    constexpr once_flag() noexcept = default;
+
+    /// Deleted copy constructor
+    once_flag(const once_flag&) = delete;
+    /// Deleted assignment operator
+    once_flag& operator=(const once_flag&) = delete;
+
+  private:
+    // For gthreads targets a pthread_once_t is used with pthread_once, but
+    // for most targets this doesn't work correctly for exceptional executions.
+    __gthread_once_t _M_once = __GTHREAD_ONCE_INIT;
+
+    struct _Prepare_execution;
+
+    template<typename _Callable, typename... _Args>
+      friend void
+      call_once(once_flag& __once, _Callable&& __f, _Args&&... __args);
+  };
+
+  /// @cond undocumented
+# ifdef _GLIBCXX_HAVE_TLS
+  // If TLS is available use thread-local state for the type-erased callable
+  // that is being run by std::call_once in the current thread.
+  extern __thread void* __once_callable;
+  extern __thread void (*__once_call)();
+
+  // RAII type to set up state for pthread_once call.
+  struct once_flag::_Prepare_execution
+  {
+    template<typename _Callable>
+      explicit
+      _Prepare_execution(_Callable& __c)
+      {
+	// Store address in thread-local pointer:
+	__once_callable = std::__addressof(__c);
+	// Trampoline function to invoke the closure via thread-local pointer:
+	__once_call = [] { (*static_cast<_Callable*>(__once_callable))(); };
+      }
+
+    ~_Prepare_execution()
+    {
+      // PR libstdc++/82481
+      __once_callable = nullptr;
+      __once_call = nullptr;
+    }
+
+    _Prepare_execution(const _Prepare_execution&) = delete;
+    _Prepare_execution& operator=(const _Prepare_execution&) = delete;
+  };
+
+# else
+  // Without TLS use a global std::mutex and store the callable in a
+  // global std::function.
+  extern function<void()> __once_functor;
+
+  extern void
+  __set_once_functor_lock_ptr(unique_lock<mutex>*);
+
+  extern mutex&
+  __get_once_mutex();
+
+  // RAII type to set up state for pthread_once call.
+  struct once_flag::_Prepare_execution
+  {
+    template<typename _Callable>
+      explicit
+      _Prepare_execution(_Callable& __c)
+      {
+	// Store the callable in the global std::function
+	__once_functor = __c;
+	__set_once_functor_lock_ptr(&_M_functor_lock);
+      }
+
+    ~_Prepare_execution()
+    {
+      if (_M_functor_lock)
+	__set_once_functor_lock_ptr(nullptr);
+    }
+
+  private:
+    // XXX This deadlocks if used recursively (PR 97949)
+    unique_lock<mutex> _M_functor_lock{__get_once_mutex()};
+
+    _Prepare_execution(const _Prepare_execution&) = delete;
+    _Prepare_execution& operator=(const _Prepare_execution&) = delete;
+  };
+# endif
+  /// @endcond
+
+  // This function is passed to pthread_once by std::call_once.
+  // It runs __once_call() or __once_functor().
+  extern "C" void __once_proxy(void);
+
+  /// Invoke a callable and synchronize with other calls using the same flag
+  template<typename _Callable, typename... _Args>
+    void
+    call_once(once_flag& __once, _Callable&& __f, _Args&&... __args)
+    {
+      // Closure type that runs the function
+      auto __callable = [&] {
+	  std::__invoke(std::forward<_Callable>(__f),
+			std::forward<_Args>(__args)...);
+      };
+
+      once_flag::_Prepare_execution __exec(__callable);
+
+      // XXX pthread_once does not reset the flag if an exception is thrown.
+      if (int __e = __gthread_once(&__once._M_once, &__once_proxy))
+	__throw_system_error(__e);
+    }
+
+#else // _GLIBCXX_HAS_GTHREADS
+
+  /// Flag type used by std::call_once
+  struct once_flag
+  {
+    constexpr once_flag() noexcept = default;
+
+    /// Deleted copy constructor
+    once_flag(const once_flag&) = delete;
+    /// Deleted assignment operator
+    once_flag& operator=(const once_flag&) = delete;
+
+  private:
+    // There are two different std::once_flag interfaces, abstracting four
+    // different implementations.
+    // The single-threaded interface uses the _M_activate() and _M_finish(bool)
+    // functions, which start and finish an active execution respectively.
+    // See [thread.once.callonce] in C++11 for the definition of
+    // active/passive/returning/exceptional executions.
+    enum _Bits : int { _Init = 0, _Active = 1, _Done = 2 };
+
+    int _M_once = _Bits::_Init;
+
+    // Check to see if all executions will be passive now.
+    bool
+    _M_passive() const noexcept;
+
+    // Attempts to begin an active execution.
+    bool _M_activate();
+
+    // Must be called to complete an active execution.
+    // The argument is true if the active execution was a returning execution,
+    // false if it was an exceptional execution.
+    void _M_finish(bool __returning) noexcept;
+
+    // RAII helper to call _M_finish.
+    struct _Active_execution
+    {
+      explicit _Active_execution(once_flag& __flag) : _M_flag(__flag) { }
+
+      ~_Active_execution() { _M_flag._M_finish(_M_returning); }
+
+      _Active_execution(const _Active_execution&) = delete;
+      _Active_execution& operator=(const _Active_execution&) = delete;
+
+      once_flag& _M_flag;
+      bool _M_returning = false;
+    };
+
+    template<typename _Callable, typename... _Args>
+      friend void
+      call_once(once_flag& __once, _Callable&& __f, _Args&&... __args);
+  };
+
+  // Inline definitions of std::once_flag members for single-threaded targets.
+
+  inline bool
+  once_flag::_M_passive() const noexcept
+  { return _M_once == _Bits::_Done; }
+
+  inline bool
+  once_flag::_M_activate()
+  {
+    if (_M_once == _Bits::_Init) [[__likely__]]
+      {
+	_M_once = _Bits::_Active;
+	return true;
+      }
+    else if (_M_passive()) // Caller should have checked this already.
+      return false;
+    else
+      __throw_system_error(EDEADLK);
+  }
+
+  inline void
+  once_flag::_M_finish(bool __returning) noexcept
+  { _M_once = __returning ? _Bits::_Done : _Bits::_Init; }
+
+  /// Invoke a callable and synchronize with other calls using the same flag
+  template<typename _Callable, typename... _Args>
+    inline void
+    call_once(once_flag& __once, _Callable&& __f, _Args&&... __args)
+    {
+      if (__once._M_passive())
+	return;
+      else if (__once._M_activate())
+	{
+	  once_flag::_Active_execution __exec(__once);
+
+	  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+	  // 2442. call_once() shouldn't DECAY_COPY()
+	  std::__invoke(std::forward<_Callable>(__f),
+			std::forward<_Args>(__args)...);
+
+	  // __f(__args...) did not throw
+	  __exec._M_returning = true;
+	}
+    }
+#endif // _GLIBCXX_HAS_GTHREADS
+
+  /// @} group mutexes
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif // C++11
+
+#endif // _GLIBCXX_MUTEX
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@@ -0,0 +1,238 @@
+// The -*- C++ -*- dynamic memory management header.
+
+// Copyright (C) 1994-2022 Free Software Foundation, Inc.
+
+// This file is part of GCC.
+//
+// GCC is free software; you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation; either version 3, or (at your option)
+// any later version.
+// 
+// GCC is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+// 
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file new
+ *  This is a Standard C++ Library header.
+ *
+ *  The header @c new defines several functions to manage dynamic memory and
+ *  handling memory allocation errors; see
+ *  https://gcc.gnu.org/onlinedocs/libstdc++/manual/dynamic_memory.html
+ *  for more.
+ */
+
+#ifndef _NEW
+#define _NEW
+
+#pragma GCC system_header
+
+#include <bits/c++config.h>
+#include <bits/exception.h>
+
+#pragma GCC visibility push(default)
+
+extern "C++" {
+
+namespace std 
+{
+  /**
+   *  @brief  Exception possibly thrown by @c new.
+   *  @ingroup exceptions
+   *
+   *  @c bad_alloc (or classes derived from it) is used to report allocation
+   *  errors from the throwing forms of @c new.  */
+  class bad_alloc : public exception
+  {
+  public:
+    bad_alloc() throw() { }
+
+#if __cplusplus >= 201103L
+    bad_alloc(const bad_alloc&) = default;
+    bad_alloc& operator=(const bad_alloc&) = default;
+#endif
+
+    // This declaration is not useless:
+    // http://gcc.gnu.org/onlinedocs/gcc-3.0.2/gcc_6.html#SEC118
+    virtual ~bad_alloc() throw();
+
+    // See comment in eh_exception.cc.
+    virtual const char* what() const throw();
+  };
+
+#if __cplusplus >= 201103L
+  class bad_array_new_length : public bad_alloc
+  {
+  public:
+    bad_array_new_length() throw() { }
+
+    // This declaration is not useless:
+    // http://gcc.gnu.org/onlinedocs/gcc-3.0.2/gcc_6.html#SEC118
+    virtual ~bad_array_new_length() throw();
+
+    // See comment in eh_exception.cc.
+    virtual const char* what() const throw();
+  };
+#endif
+
+#if __cpp_aligned_new
+  enum class align_val_t: size_t {};
+#endif
+
+  struct nothrow_t
+  {
+#if __cplusplus >= 201103L
+    explicit nothrow_t() = default;
+#endif
+  };
+
+  extern const nothrow_t nothrow;
+
+  /** If you write your own error handler to be called by @c new, it must
+   *  be of this type.  */
+  typedef void (*new_handler)();
+
+  /// Takes a replacement handler as the argument, returns the
+  /// previous handler.
+  new_handler set_new_handler(new_handler) throw();
+
+#if __cplusplus >= 201103L
+  /// Return the current new handler.
+  new_handler get_new_handler() noexcept;
+#endif
+} // namespace std
+
+//@{
+/** These are replaceable signatures:
+ *  - normal single new and delete (no arguments, throw @c bad_alloc on error)
+ *  - normal array new and delete (same)
+ *  - @c nothrow single new and delete (take a @c nothrow argument, return
+ *    @c NULL on error)
+ *  - @c nothrow array new and delete (same)
+ *
+ *  Placement new and delete signatures (take a memory address argument,
+ *  does nothing) may not be replaced by a user's program.
+*/
+_GLIBCXX_NODISCARD void* operator new(std::size_t) _GLIBCXX_THROW (std::bad_alloc)
+  __attribute__((__externally_visible__));
+_GLIBCXX_NODISCARD void* operator new[](std::size_t) _GLIBCXX_THROW (std::bad_alloc)
+  __attribute__((__externally_visible__));
+void operator delete(void*) _GLIBCXX_USE_NOEXCEPT
+  __attribute__((__externally_visible__));
+void operator delete[](void*) _GLIBCXX_USE_NOEXCEPT
+  __attribute__((__externally_visible__));
+#if __cpp_sized_deallocation
+void operator delete(void*, std::size_t) _GLIBCXX_USE_NOEXCEPT
+  __attribute__((__externally_visible__));
+void operator delete[](void*, std::size_t) _GLIBCXX_USE_NOEXCEPT
+  __attribute__((__externally_visible__));
+#endif
+_GLIBCXX_NODISCARD void* operator new(std::size_t, const std::nothrow_t&) _GLIBCXX_USE_NOEXCEPT
+  __attribute__((__externally_visible__, __alloc_size__ (1), __malloc__));
+_GLIBCXX_NODISCARD void* operator new[](std::size_t, const std::nothrow_t&) _GLIBCXX_USE_NOEXCEPT
+  __attribute__((__externally_visible__, __alloc_size__ (1), __malloc__));
+void operator delete(void*, const std::nothrow_t&) _GLIBCXX_USE_NOEXCEPT
+  __attribute__((__externally_visible__));
+void operator delete[](void*, const std::nothrow_t&) _GLIBCXX_USE_NOEXCEPT
+  __attribute__((__externally_visible__));
+#if __cpp_aligned_new
+_GLIBCXX_NODISCARD void* operator new(std::size_t, std::align_val_t)
+  __attribute__((__externally_visible__, __alloc_size__ (1), __malloc__));
+_GLIBCXX_NODISCARD void* operator new(std::size_t, std::align_val_t, const std::nothrow_t&)
+  _GLIBCXX_USE_NOEXCEPT __attribute__((__externally_visible__, __alloc_size__ (1), __malloc__));
+void operator delete(void*, std::align_val_t)
+  _GLIBCXX_USE_NOEXCEPT __attribute__((__externally_visible__));
+void operator delete(void*, std::align_val_t, const std::nothrow_t&)
+  _GLIBCXX_USE_NOEXCEPT __attribute__((__externally_visible__));
+_GLIBCXX_NODISCARD void* operator new[](std::size_t, std::align_val_t)
+  __attribute__((__externally_visible__, __alloc_size__ (1), __malloc__));
+_GLIBCXX_NODISCARD void* operator new[](std::size_t, std::align_val_t, const std::nothrow_t&)
+  _GLIBCXX_USE_NOEXCEPT __attribute__((__externally_visible__, __alloc_size__ (1), __malloc__));
+void operator delete[](void*, std::align_val_t)
+  _GLIBCXX_USE_NOEXCEPT __attribute__((__externally_visible__));
+void operator delete[](void*, std::align_val_t, const std::nothrow_t&)
+  _GLIBCXX_USE_NOEXCEPT __attribute__((__externally_visible__));
+#if __cpp_sized_deallocation
+void operator delete(void*, std::size_t, std::align_val_t)
+  _GLIBCXX_USE_NOEXCEPT __attribute__((__externally_visible__));
+void operator delete[](void*, std::size_t, std::align_val_t)
+  _GLIBCXX_USE_NOEXCEPT __attribute__((__externally_visible__));
+#endif // __cpp_sized_deallocation
+#endif // __cpp_aligned_new
+
+// Default placement versions of operator new.
+_GLIBCXX_NODISCARD inline void* operator new(std::size_t, void* __p) _GLIBCXX_USE_NOEXCEPT
+{ return __p; }
+_GLIBCXX_NODISCARD inline void* operator new[](std::size_t, void* __p) _GLIBCXX_USE_NOEXCEPT
+{ return __p; }
+
+// Default placement versions of operator delete.
+inline void operator delete  (void*, void*) _GLIBCXX_USE_NOEXCEPT { }
+inline void operator delete[](void*, void*) _GLIBCXX_USE_NOEXCEPT { }
+//@}
+} // extern "C++"
+
+#if __cplusplus >= 201703L
+namespace std
+{
+#ifdef _GLIBCXX_HAVE_BUILTIN_LAUNDER
+#define __cpp_lib_launder 201606L
+  /// Pointer optimization barrier [ptr.launder]
+  template<typename _Tp>
+    [[nodiscard]] constexpr _Tp*
+    launder(_Tp* __p) noexcept
+    { return __builtin_launder(__p); }
+
+  // The program is ill-formed if T is a function type or
+  // (possibly cv-qualified) void.
+
+  template<typename _Ret, typename... _Args _GLIBCXX_NOEXCEPT_PARM>
+    void launder(_Ret (*)(_Args...) _GLIBCXX_NOEXCEPT_QUAL) = delete;
+  template<typename _Ret, typename... _Args _GLIBCXX_NOEXCEPT_PARM>
+    void launder(_Ret (*)(_Args......) _GLIBCXX_NOEXCEPT_QUAL) = delete;
+
+  void launder(void*) = delete;
+  void launder(const void*) = delete;
+  void launder(volatile void*) = delete;
+  void launder(const volatile void*) = delete;
+#endif // _GLIBCXX_HAVE_BUILTIN_LAUNDER
+
+#ifdef __GCC_DESTRUCTIVE_SIZE
+# define __cpp_lib_hardware_interference_size 201703L
+  inline constexpr size_t hardware_destructive_interference_size = __GCC_DESTRUCTIVE_SIZE;
+  inline constexpr size_t hardware_constructive_interference_size = __GCC_CONSTRUCTIVE_SIZE;
+#endif // __GCC_DESTRUCTIVE_SIZE
+}
+#endif // C++17
+
+#if __cplusplus > 201703L
+namespace std
+{
+  /// Tag type used to declare a class-specific operator delete that can
+  /// invoke the destructor before deallocating the memory.
+  struct destroying_delete_t
+  {
+    explicit destroying_delete_t() = default;
+  };
+  /// Tag variable of type destroying_delete_t.
+  inline constexpr destroying_delete_t destroying_delete{};
+}
+// Only define the feature test macro if the compiler supports the feature:
+#if __cpp_impl_destroying_delete
+# define __cpp_lib_destroying_delete 201806L
+#endif
+#endif // C++20
+
+#pragma GCC visibility pop
+
+#endif
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@@ -0,0 +1,747 @@
+// <numeric> -*- C++ -*-
+
+// Copyright (C) 2001-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/*
+ *
+ * Copyright (c) 1994
+ * Hewlett-Packard Company
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Hewlett-Packard Company makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ *
+ *
+ * Copyright (c) 1996,1997
+ * Silicon Graphics Computer Systems, Inc.
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Silicon Graphics makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ */
+
+/** @file include/numeric
+ *  This is a Standard C++ Library header.
+ */
+
+#ifndef _GLIBCXX_NUMERIC
+#define _GLIBCXX_NUMERIC 1
+
+#pragma GCC system_header
+
+#include <bits/c++config.h>
+#include <bits/stl_iterator_base_types.h>
+#include <bits/stl_numeric.h>
+
+#ifdef _GLIBCXX_PARALLEL
+# include <parallel/numeric>
+#endif
+
+#if __cplusplus >= 201402L
+# include <type_traits>
+# include <bit>
+# include <ext/numeric_traits.h>
+#endif
+
+#if __cplusplus >= 201703L
+# include <bits/stl_function.h>
+#endif
+
+#if __cplusplus > 201703L
+# include <limits>
+#endif
+
+/**
+ * @defgroup numerics Numerics
+ *
+ * Components for performing numeric operations. Includes support for
+ * complex number types, random number generation, numeric (n-at-a-time)
+ * arrays, generalized numeric algorithms, and mathematical special functions.
+ */
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+#if __cplusplus >= 201402L
+namespace __detail
+{
+  // Like std::abs, but supports unsigned types and returns the specified type,
+  // so |std::numeric_limits<_Tp>::min()| is OK if representable in _Res.
+  template<typename _Res, typename _Tp>
+    constexpr _Res
+    __abs_r(_Tp __val)
+    {
+      static_assert(sizeof(_Res) >= sizeof(_Tp),
+	  "result type must be at least as wide as the input type");
+
+      if (__val >= 0)
+	return __val;
+#ifdef _GLIBCXX_ASSERTIONS
+      if (!__is_constant_evaluated()) // overflow already detected in constexpr
+	__glibcxx_assert(__val != __gnu_cxx::__int_traits<_Res>::__min);
+#endif
+      return -static_cast<_Res>(__val);
+    }
+
+  template<typename> void __abs_r(bool) = delete;
+
+  // GCD implementation, using Stein's algorithm
+  template<typename _Tp>
+    constexpr _Tp
+    __gcd(_Tp __m, _Tp __n)
+    {
+      static_assert(is_unsigned<_Tp>::value, "type must be unsigned");
+
+      if (__m == 0)
+	return __n;
+      if (__n == 0)
+	return __m;
+
+      const int __i = std::__countr_zero(__m);
+      __m >>= __i;
+      const int __j = std::__countr_zero(__n);
+      __n >>= __j;
+      const int __k = __i < __j ? __i : __j; // min(i, j)
+
+      while (true)
+	{
+	  if (__m > __n)
+	    {
+	      _Tp __tmp = __m;
+	      __m = __n;
+	      __n = __tmp;
+	    }
+
+	  __n -= __m;
+
+	  if (__n == 0)
+	    return __m << __k;
+
+	  __n >>= std::__countr_zero(__n);
+	}
+    }
+} // namespace __detail
+
+#if __cplusplus >= 201703L
+
+#define __cpp_lib_gcd_lcm 201606L
+// These were used in drafts of SD-6:
+#define __cpp_lib_gcd 201606L
+#define __cpp_lib_lcm 201606L
+
+  /// Greatest common divisor
+  template<typename _Mn, typename _Nn>
+    constexpr common_type_t<_Mn, _Nn>
+    gcd(_Mn __m, _Nn __n) noexcept
+    {
+      static_assert(is_integral_v<_Mn> && is_integral_v<_Nn>,
+		    "std::gcd arguments must be integers");
+      static_assert(_Mn(2) == 2 && _Nn(2) == 2,
+		    "std::gcd arguments must not be bool");
+      using _Ct = common_type_t<_Mn, _Nn>;
+      const _Ct __m2 = __detail::__abs_r<_Ct>(__m);
+      const _Ct __n2 = __detail::__abs_r<_Ct>(__n);
+      return __detail::__gcd<make_unsigned_t<_Ct>>(__m2, __n2);
+    }
+
+  /// Least common multiple
+  template<typename _Mn, typename _Nn>
+    constexpr common_type_t<_Mn, _Nn>
+    lcm(_Mn __m, _Nn __n) noexcept
+    {
+      static_assert(is_integral_v<_Mn> && is_integral_v<_Nn>,
+		    "std::lcm arguments must be integers");
+      static_assert(_Mn(2) == 2 && _Nn(2) == 2,
+		    "std::lcm arguments must not be bool");
+      using _Ct = common_type_t<_Mn, _Nn>;
+      const _Ct __m2 = __detail::__abs_r<_Ct>(__m);
+      const _Ct __n2 = __detail::__abs_r<_Ct>(__n);
+      if (__m2 == 0 || __n2 == 0)
+	return 0;
+      _Ct __r = __m2 / __detail::__gcd<make_unsigned_t<_Ct>>(__m2, __n2);
+
+      if constexpr (is_signed_v<_Ct>)
+	if (__is_constant_evaluated())
+	  return __r * __n2; // constant evaluation can detect overflow here.
+
+      bool __overflow = __builtin_mul_overflow(__r, __n2, &__r);
+      __glibcxx_assert(!__overflow);
+      return __r;
+    }
+
+#endif // C++17
+#endif // C++14
+
+#if __cplusplus > 201703L
+
+  // midpoint
+# define __cpp_lib_interpolate 201902L
+
+  template<typename _Tp>
+    constexpr
+    enable_if_t<__and_v<is_arithmetic<_Tp>, is_same<remove_cv_t<_Tp>, _Tp>,
+			__not_<is_same<_Tp, bool>>>,
+		_Tp>
+    midpoint(_Tp __a, _Tp __b) noexcept
+    {
+      if constexpr (is_integral_v<_Tp>)
+	{
+	  using _Up = make_unsigned_t<_Tp>;
+
+	  int __k = 1;
+	  _Up __m = __a;
+	  _Up __M = __b;
+	  if (__a > __b)
+	    {
+	      __k = -1;
+	      __m = __b;
+	      __M = __a;
+	    }
+	  return __a + __k * _Tp(_Up(__M - __m) / 2);
+	}
+      else // is_floating
+	{
+	  constexpr _Tp __lo = numeric_limits<_Tp>::min() * 2;
+	  constexpr _Tp __hi = numeric_limits<_Tp>::max() / 2;
+	  const _Tp __abs_a = __a < 0 ? -__a : __a;
+	  const _Tp __abs_b = __b < 0 ? -__b : __b;
+	  if (__abs_a <= __hi && __abs_b <= __hi) [[likely]]
+	    return (__a + __b) / 2; // always correctly rounded
+	  if (__abs_a < __lo) // not safe to halve __a
+	    return __a + __b/2;
+	  if (__abs_b < __lo) // not safe to halve __b
+	    return __a/2 + __b;
+	  return __a/2 + __b/2;	    // otherwise correctly rounded
+	}
+    }
+
+  template<typename _Tp>
+    constexpr enable_if_t<is_object_v<_Tp>, _Tp*>
+    midpoint(_Tp* __a, _Tp* __b) noexcept
+    {
+      static_assert( sizeof(_Tp) != 0, "type must be complete" );
+      return __a  + (__b - __a) / 2;
+    }
+#endif // C++20
+
+#if __cplusplus >= 201703L
+
+#if __cplusplus > 201703L
+#define __cpp_lib_constexpr_numeric 201911L
+#endif
+
+  /// @addtogroup numeric_ops
+  /// @{
+
+  /**
+   *  @brief  Calculate reduction of values in a range.
+   *
+   *  @param  __first  Start of range.
+   *  @param  __last  End of range.
+   *  @param  __init  Starting value to add other values to.
+   *  @param  __binary_op A binary function object.
+   *  @return  The final sum.
+   *
+   *  Reduce the values in the range `[first,last)` using a binary operation.
+   *  The initial value is `init`.  The values are not necessarily processed
+   *  in order.
+   *
+   *  This algorithm is similar to `std::accumulate` but is not required to
+   *  perform the operations in order from first to last. For operations
+   *  that are commutative and associative the result will be the same as
+   *  for `std::accumulate`, but for other operations (such as floating point
+   *  arithmetic) the result can be different.
+   */
+  template<typename _InputIterator, typename _Tp, typename _BinaryOperation>
+    _GLIBCXX20_CONSTEXPR
+    _Tp
+    reduce(_InputIterator __first, _InputIterator __last, _Tp __init,
+	   _BinaryOperation __binary_op)
+    {
+      using __ref = typename iterator_traits<_InputIterator>::reference;
+      static_assert(is_invocable_r_v<_Tp, _BinaryOperation&, _Tp&, __ref>);
+      static_assert(is_invocable_r_v<_Tp, _BinaryOperation&, __ref, _Tp&>);
+      static_assert(is_invocable_r_v<_Tp, _BinaryOperation&, _Tp&, _Tp&>);
+      static_assert(is_invocable_r_v<_Tp, _BinaryOperation&, __ref, __ref>);
+      if constexpr (__is_random_access_iter<_InputIterator>::value)
+	{
+	  while ((__last - __first) >= 4)
+	    {
+	      _Tp __v1 = __binary_op(__first[0], __first[1]);
+	      _Tp __v2 = __binary_op(__first[2], __first[3]);
+	      _Tp __v3 = __binary_op(__v1, __v2);
+	      __init = __binary_op(__init, __v3);
+	      __first += 4;
+	    }
+	}
+      for (; __first != __last; ++__first)
+	__init = __binary_op(__init, *__first);
+      return __init;
+    }
+
+ /**
+   *  @brief  Calculate reduction of values in a range.
+   *
+   *  @param  __first  Start of range.
+   *  @param  __last  End of range.
+   *  @param  __init  Starting value to add other values to.
+   *  @return  The final sum.
+   *
+   *  Reduce the values in the range `[first,last)` using addition.
+   *  Equivalent to calling `std::reduce(first, last, init, std::plus<>())`.
+   */
+  template<typename _InputIterator, typename _Tp>
+    _GLIBCXX20_CONSTEXPR
+    inline _Tp
+    reduce(_InputIterator __first, _InputIterator __last, _Tp __init)
+    { return std::reduce(__first, __last, std::move(__init), plus<>()); }
+
+  /**
+   *  @brief  Calculate reduction of values in a range.
+   *
+   *  @param  __first  Start of range.
+   *  @param  __last  End of range.
+   *  @return  The final sum.
+   *
+   *  Reduce the values in the range `[first,last)` using addition, with
+   *  an initial value of `T{}`, where `T` is the iterator's value type.
+   *  Equivalent to calling `std::reduce(first, last, T{}, std::plus<>())`.
+   */
+  template<typename _InputIterator>
+    _GLIBCXX20_CONSTEXPR
+    inline typename iterator_traits<_InputIterator>::value_type
+    reduce(_InputIterator __first, _InputIterator __last)
+    {
+      using value_type = typename iterator_traits<_InputIterator>::value_type;
+      return std::reduce(__first, __last, value_type{}, plus<>());
+    }
+
+  /**
+   *  @brief  Combine elements from two ranges and reduce
+   *
+   *  @param  __first1  Start of first range.
+   *  @param  __last1  End of first range.
+   *  @param  __first2  Start of second range.
+   *  @param  __init  Starting value to add other values to.
+   *  @param  __binary_op1 The function used to perform reduction.
+   *  @param  __binary_op2 The function used to combine values from the ranges.
+   *  @return  The final sum.
+   *
+   *  Call `binary_op2(first1[n],first2[n])` for each `n` in `[0,last1-first1)`
+   *  and then use `binary_op1` to reduce the values returned by `binary_op2`
+   *  to a single value of type `T`.
+   *
+   *  The range beginning at `first2` must contain at least `last1-first1`
+   *  elements.
+   */
+  template<typename _InputIterator1, typename _InputIterator2, typename _Tp,
+	   typename _BinaryOperation1, typename _BinaryOperation2>
+    _GLIBCXX20_CONSTEXPR
+    _Tp
+    transform_reduce(_InputIterator1 __first1, _InputIterator1 __last1,
+		     _InputIterator2 __first2, _Tp __init,
+		     _BinaryOperation1 __binary_op1,
+		     _BinaryOperation2 __binary_op2)
+    {
+      if constexpr (__and_v<__is_random_access_iter<_InputIterator1>,
+			    __is_random_access_iter<_InputIterator2>>)
+	{
+	  while ((__last1 - __first1) >= 4)
+	    {
+	      _Tp __v1 = __binary_op1(__binary_op2(__first1[0], __first2[0]),
+				      __binary_op2(__first1[1], __first2[1]));
+	      _Tp __v2 = __binary_op1(__binary_op2(__first1[2], __first2[2]),
+				      __binary_op2(__first1[3], __first2[3]));
+	      _Tp __v3 = __binary_op1(__v1, __v2);
+	      __init = __binary_op1(__init, __v3);
+	      __first1 += 4;
+	      __first2 += 4;
+	    }
+	}
+      for (; __first1 != __last1; ++__first1, (void) ++__first2)
+	__init = __binary_op1(__init, __binary_op2(*__first1, *__first2));
+      return __init;
+    }
+
+  /**
+   *  @brief  Combine elements from two ranges and reduce
+   *
+   *  @param  __first1  Start of first range.
+   *  @param  __last1  End of first range.
+   *  @param  __first2  Start of second range.
+   *  @param  __init  Starting value to add other values to.
+   *  @return  The final sum.
+   *
+   *  Call `first1[n]*first2[n]` for each `n` in `[0,last1-first1)` and then
+   *  use addition to sum those products to a single value of type `T`.
+   *
+   *  The range beginning at `first2` must contain at least `last1-first1`
+   *  elements.
+   */
+  template<typename _InputIterator1, typename _InputIterator2, typename _Tp>
+    _GLIBCXX20_CONSTEXPR
+    inline _Tp
+    transform_reduce(_InputIterator1 __first1, _InputIterator1 __last1,
+		     _InputIterator2 __first2, _Tp __init)
+    {
+      return std::transform_reduce(__first1, __last1, __first2,
+				   std::move(__init),
+				   plus<>(), multiplies<>());
+    }
+
+  /**
+   *  @brief  Transform the elements of a range and reduce
+   *
+   *  @param  __first  Start of range.
+   *  @param  __last  End of range.
+   *  @param  __init  Starting value to add other values to.
+   *  @param  __binary_op The function used to perform reduction.
+   *  @param  __unary_op The function used to transform values from the range.
+   *  @return  The final sum.
+   *
+   *  Call `unary_op(first[n])` for each `n` in `[0,last-first)` and then
+   *  use `binary_op` to reduce the values returned by `unary_op`
+   *  to a single value of type `T`.
+   */
+  template<typename _InputIterator, typename _Tp,
+	   typename _BinaryOperation, typename _UnaryOperation>
+    _GLIBCXX20_CONSTEXPR
+    _Tp
+    transform_reduce(_InputIterator __first, _InputIterator __last, _Tp __init,
+		     _BinaryOperation __binary_op, _UnaryOperation __unary_op)
+    {
+      if constexpr (__is_random_access_iter<_InputIterator>::value)
+	{
+	  while ((__last - __first) >= 4)
+	    {
+	      _Tp __v1 = __binary_op(__unary_op(__first[0]),
+				     __unary_op(__first[1]));
+	      _Tp __v2 = __binary_op(__unary_op(__first[2]),
+				     __unary_op(__first[3]));
+	      _Tp __v3 = __binary_op(__v1, __v2);
+	      __init = __binary_op(__init, __v3);
+	      __first += 4;
+	    }
+	}
+      for (; __first != __last; ++__first)
+	__init = __binary_op(__init, __unary_op(*__first));
+      return __init;
+    }
+
+  /** @brief Output the cumulative sum of one range to a second range
+   *
+   *  @param __first  Start of input range.
+   *  @param __last   End of input range.
+   *  @param __result Start of output range.
+   *  @param __init   Initial value.
+   *  @param __binary_op Function to perform summation.
+   *  @return The end of the output range.
+   *
+   *  Write the cumulative sum (aka prefix sum, aka scan) of the input range
+   *  to the output range. Each element of the output range contains the
+   *  running total of all earlier elements (and the initial value),
+   *  using `binary_op` for summation.
+   *
+   *  This function generates an "exclusive" scan, meaning the Nth element
+   *  of the output range is the sum of the first N-1 input elements,
+   *  so the Nth input element is not included.
+   */
+  template<typename _InputIterator, typename _OutputIterator, typename _Tp,
+	   typename _BinaryOperation>
+    _GLIBCXX20_CONSTEXPR
+    _OutputIterator
+    exclusive_scan(_InputIterator __first, _InputIterator __last,
+		   _OutputIterator __result, _Tp __init,
+		   _BinaryOperation __binary_op)
+    {
+      while (__first != __last)
+	{
+	  auto __v = __init;
+	  __init = __binary_op(__init, *__first);
+	  ++__first;
+	  *__result++ = std::move(__v);
+	}
+      return __result;
+    }
+
+  /** @brief Output the cumulative sum of one range to a second range
+   *
+   *  @param __first  Start of input range.
+   *  @param __last   End of input range.
+   *  @param __result Start of output range.
+   *  @param __init   Initial value.
+   *  @return The end of the output range.
+   *
+   *  Write the cumulative sum (aka prefix sum, aka scan) of the input range
+   *  to the output range. Each element of the output range contains the
+   *  running total of all earlier elements (and the initial value),
+   *  using `std::plus<>` for summation.
+   *
+   *  This function generates an "exclusive" scan, meaning the Nth element
+   *  of the output range is the sum of the first N-1 input elements,
+   *  so the Nth input element is not included.
+   */
+  template<typename _InputIterator, typename _OutputIterator, typename _Tp>
+    _GLIBCXX20_CONSTEXPR
+    inline _OutputIterator
+    exclusive_scan(_InputIterator __first, _InputIterator __last,
+		   _OutputIterator __result, _Tp __init)
+    {
+      return std::exclusive_scan(__first, __last, __result, std::move(__init),
+				 plus<>());
+    }
+
+  /** @brief Output the cumulative sum of one range to a second range
+   *
+   *  @param __first  Start of input range.
+   *  @param __last   End of input range.
+   *  @param __result Start of output range.
+   *  @param __binary_op Function to perform summation.
+   *  @param __init   Initial value.
+   *  @return The end of the output range.
+   *
+   *  Write the cumulative sum (aka prefix sum, aka scan) of the input range
+   *  to the output range. Each element of the output range contains the
+   *  running total of all earlier elements (and the initial value),
+   *  using `binary_op` for summation.
+   *
+   *  This function generates an "inclusive" scan, meaning the Nth element
+   *  of the output range is the sum of the first N input elements,
+   *  so the Nth input element is included.
+   */
+  template<typename _InputIterator, typename _OutputIterator,
+	   typename _BinaryOperation, typename _Tp>
+    _GLIBCXX20_CONSTEXPR
+    _OutputIterator
+    inclusive_scan(_InputIterator __first, _InputIterator __last,
+		   _OutputIterator __result, _BinaryOperation __binary_op,
+		   _Tp __init)
+    {
+      for (; __first != __last; ++__first)
+	*__result++ = __init = __binary_op(__init, *__first);
+      return __result;
+    }
+
+  /** @brief Output the cumulative sum of one range to a second range
+   *
+   *  @param __first  Start of input range.
+   *  @param __last   End of input range.
+   *  @param __result Start of output range.
+   *  @param __binary_op Function to perform summation.
+   *  @return The end of the output range.
+   *
+   *  Write the cumulative sum (aka prefix sum, aka scan) of the input range
+   *  to the output range. Each element of the output range contains the
+   *  running total of all earlier elements, using `binary_op` for summation.
+   *
+   *  This function generates an "inclusive" scan, meaning the Nth element
+   *  of the output range is the sum of the first N input elements,
+   *  so the Nth input element is included.
+   */
+  template<typename _InputIterator, typename _OutputIterator,
+	   typename _BinaryOperation>
+    _GLIBCXX20_CONSTEXPR
+    _OutputIterator
+    inclusive_scan(_InputIterator __first, _InputIterator __last,
+		   _OutputIterator __result, _BinaryOperation __binary_op)
+    {
+      if (__first != __last)
+	{
+	  auto __init = *__first;
+	  *__result++ = __init;
+	  ++__first;
+	  if (__first != __last)
+	    __result = std::inclusive_scan(__first, __last, __result,
+					   __binary_op, std::move(__init));
+	}
+      return __result;
+    }
+
+  /** @brief Output the cumulative sum of one range to a second range
+   *
+   *  @param __first  Start of input range.
+   *  @param __last   End of input range.
+   *  @param __result Start of output range.
+   *  @return The end of the output range.
+   *
+   *  Write the cumulative sum (aka prefix sum, aka scan) of the input range
+   *  to the output range. Each element of the output range contains the
+   *  running total of all earlier elements, using `std::plus<>` for summation.
+   *
+   *  This function generates an "inclusive" scan, meaning the Nth element
+   *  of the output range is the sum of the first N input elements,
+   *  so the Nth input element is included.
+   */
+  template<typename _InputIterator, typename _OutputIterator>
+    _GLIBCXX20_CONSTEXPR
+    inline _OutputIterator
+    inclusive_scan(_InputIterator __first, _InputIterator __last,
+		   _OutputIterator __result)
+    { return std::inclusive_scan(__first, __last, __result, plus<>()); }
+
+  /** @brief Output the cumulative sum of one range to a second range
+   *
+   *  @param __first  Start of input range.
+   *  @param __last   End of input range.
+   *  @param __result Start of output range.
+   *  @param __init   Initial value.
+   *  @param __binary_op Function to perform summation.
+   *  @param __unary_op Function to transform elements of the input range.
+   *  @return The end of the output range.
+   *
+   *  Write the cumulative sum (aka prefix sum, aka scan) of the input range
+   *  to the output range. Each element of the output range contains the
+   *  running total of all earlier elements (and the initial value),
+   *  using `__unary_op` to transform the input elements
+   *  and using `__binary_op` for summation.
+   *
+   *  This function generates an "exclusive" scan, meaning the Nth element
+   *  of the output range is the sum of the first N-1 input elements,
+   *  so the Nth input element is not included.
+   */
+  template<typename _InputIterator, typename _OutputIterator, typename _Tp,
+	   typename _BinaryOperation, typename _UnaryOperation>
+    _GLIBCXX20_CONSTEXPR
+    _OutputIterator
+    transform_exclusive_scan(_InputIterator __first, _InputIterator __last,
+			     _OutputIterator __result, _Tp __init,
+			     _BinaryOperation __binary_op,
+			     _UnaryOperation __unary_op)
+    {
+      while (__first != __last)
+	{
+	  auto __v = __init;
+	  __init = __binary_op(__init, __unary_op(*__first));
+	  ++__first;
+	  *__result++ = std::move(__v);
+	}
+      return __result;
+    }
+
+  /** @brief Output the cumulative sum of one range to a second range
+   *
+   *  @param __first  Start of input range.
+   *  @param __last   End of input range.
+   *  @param __result Start of output range.
+   *  @param __binary_op Function to perform summation.
+   *  @param __unary_op Function to transform elements of the input range.
+   *  @param __init   Initial value.
+   *  @return The end of the output range.
+   *
+   *  Write the cumulative sum (aka prefix sum, aka scan) of the input range
+   *  to the output range. Each element of the output range contains the
+   *  running total of all earlier elements (and the initial value),
+   *  using `__unary_op` to transform the input elements
+   *  and using `__binary_op` for summation.
+   *
+   *  This function generates an "inclusive" scan, meaning the Nth element
+   *  of the output range is the sum of the first N input elements,
+   *  so the Nth input element is included.
+   */
+  template<typename _InputIterator, typename _OutputIterator,
+	   typename _BinaryOperation, typename _UnaryOperation, typename _Tp>
+    _GLIBCXX20_CONSTEXPR
+    _OutputIterator
+    transform_inclusive_scan(_InputIterator __first, _InputIterator __last,
+			     _OutputIterator __result,
+			     _BinaryOperation __binary_op,
+			     _UnaryOperation __unary_op,
+			     _Tp __init)
+    {
+      for (; __first != __last; ++__first)
+	*__result++ = __init = __binary_op(__init, __unary_op(*__first));
+      return __result;
+    }
+
+  /** @brief Output the cumulative sum of one range to a second range
+   *
+   *  @param __first  Start of input range.
+   *  @param __last   End of input range.
+   *  @param __result Start of output range.
+   *  @param __binary_op Function to perform summation.
+   *  @param __unary_op Function to transform elements of the input range.
+   *  @return The end of the output range.
+   *
+   *  Write the cumulative sum (aka prefix sum, aka scan) of the input range
+   *  to the output range. Each element of the output range contains the
+   *  running total of all earlier elements,
+   *  using `__unary_op` to transform the input elements
+   *  and using `__binary_op` for summation.
+   *
+   *  This function generates an "inclusive" scan, meaning the Nth element
+   *  of the output range is the sum of the first N input elements,
+   *  so the Nth input element is included.
+   */
+  template<typename _InputIterator, typename _OutputIterator,
+	  typename _BinaryOperation, typename _UnaryOperation>
+    _GLIBCXX20_CONSTEXPR
+    _OutputIterator
+    transform_inclusive_scan(_InputIterator __first, _InputIterator __last,
+			     _OutputIterator __result,
+			     _BinaryOperation __binary_op,
+			     _UnaryOperation __unary_op)
+    {
+      if (__first != __last)
+	{
+	  auto __init = __unary_op(*__first);
+	  *__result++ = __init;
+	  ++__first;
+	  if (__first != __last)
+	    __result = std::transform_inclusive_scan(__first, __last, __result,
+						     __binary_op, __unary_op,
+						     std::move(__init));
+	}
+      return __result;
+    }
+
+  /// @} group numeric_ops
+#endif // C++17
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#if __cplusplus >= 201703L
+// Parallel STL algorithms
+# if _PSTL_EXECUTION_POLICIES_DEFINED
+// If <execution> has already been included, pull in implementations
+#  include <pstl/glue_numeric_impl.h>
+# else
+// Otherwise just pull in forward declarations
+#  include <pstl/glue_numeric_defs.h>
+#  define _PSTL_NUMERIC_FORWARD_DECLARED 1
+# endif
+
+// Feature test macro for parallel algorithms
+# define __cpp_lib_parallel_algorithm 201603L
+#endif // C++17
+
+#endif /* _GLIBCXX_NUMERIC */
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@@ -0,0 +1,835 @@
+// Output streams -*- C++ -*-
+
+// Copyright (C) 1997-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file include/ostream
+ *  This is a Standard C++ Library header.
+ */
+
+//
+// ISO C++ 14882: 27.6.2  Output streams
+//
+
+#ifndef _GLIBCXX_OSTREAM
+#define _GLIBCXX_OSTREAM 1
+
+#pragma GCC system_header
+
+#include <ios>
+#include <bits/ostream_insert.h>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /**
+   *  @brief  Template class basic_ostream.
+   *  @ingroup io
+   *
+   *  @tparam _CharT  Type of character stream.
+   *  @tparam _Traits  Traits for character type, defaults to
+   *                   char_traits<_CharT>.
+   *
+   *  This is the base class for all output streams.  It provides text
+   *  formatting of all builtin types, and communicates with any class
+   *  derived from basic_streambuf to do the actual output.
+  */
+  template<typename _CharT, typename _Traits>
+    class basic_ostream : virtual public basic_ios<_CharT, _Traits>
+    {
+    public:
+      // Types (inherited from basic_ios):
+      typedef _CharT			 		char_type;
+      typedef typename _Traits::int_type 		int_type;
+      typedef typename _Traits::pos_type 		pos_type;
+      typedef typename _Traits::off_type 		off_type;
+      typedef _Traits			 		traits_type;
+
+      // Non-standard Types:
+      typedef basic_streambuf<_CharT, _Traits> 		__streambuf_type;
+      typedef basic_ios<_CharT, _Traits>		__ios_type;
+      typedef basic_ostream<_CharT, _Traits>		__ostream_type;
+      typedef num_put<_CharT, ostreambuf_iterator<_CharT, _Traits> >
+      							__num_put_type;
+      typedef ctype<_CharT>	      			__ctype_type;
+
+      /**
+       *  @brief  Base constructor.
+       *
+       *  This ctor is almost never called by the user directly, rather from
+       *  derived classes' initialization lists, which pass a pointer to
+       *  their own stream buffer.
+      */
+      explicit
+      basic_ostream(__streambuf_type* __sb)
+      { this->init(__sb); }
+
+      /**
+       *  @brief  Base destructor.
+       *
+       *  This does very little apart from providing a virtual base dtor.
+      */
+      virtual
+      ~basic_ostream() { }
+
+      /// Safe prefix/suffix operations.
+      class sentry;
+      friend class sentry;
+
+      ///@{
+      /**
+       *  @brief  Interface for manipulators.
+       *
+       *  Manipulators such as @c std::endl and @c std::hex use these
+       *  functions in constructs like "std::cout << std::endl".  For more
+       *  information, see the iomanip header.
+      */
+      __ostream_type&
+      operator<<(__ostream_type& (*__pf)(__ostream_type&))
+      {
+	// _GLIBCXX_RESOLVE_LIB_DEFECTS
+	// DR 60. What is a formatted input function?
+	// The inserters for manipulators are *not* formatted output functions.
+	return __pf(*this);
+      }
+
+      __ostream_type&
+      operator<<(__ios_type& (*__pf)(__ios_type&))
+      {
+	// _GLIBCXX_RESOLVE_LIB_DEFECTS
+	// DR 60. What is a formatted input function?
+	// The inserters for manipulators are *not* formatted output functions.
+	__pf(*this);
+	return *this;
+      }
+
+      __ostream_type&
+      operator<<(ios_base& (*__pf) (ios_base&))
+      {
+	// _GLIBCXX_RESOLVE_LIB_DEFECTS
+	// DR 60. What is a formatted input function?
+	// The inserters for manipulators are *not* formatted output functions.
+	__pf(*this);
+	return *this;
+      }
+      ///@}
+
+      ///@{
+      /**
+       *  @name Inserters
+       *
+       *  All the @c operator<< functions (aka <em>formatted output
+       *  functions</em>) have some common behavior.  Each starts by
+       *  constructing a temporary object of type std::basic_ostream::sentry.
+       *  This can have several effects, concluding with the setting of a
+       *  status flag; see the sentry documentation for more.
+       *
+       *  If the sentry status is good, the function tries to generate
+       *  whatever data is appropriate for the type of the argument.
+       *
+       *  If an exception is thrown during insertion, ios_base::badbit
+       *  will be turned on in the stream's error state without causing an
+       *  ios_base::failure to be thrown.  The original exception will then
+       *  be rethrown.
+      */
+
+      ///@{
+      /**
+       *  @brief Integer arithmetic inserters
+       *  @param  __n A variable of builtin integral type.
+       *  @return  @c *this if successful
+       *
+       *  These functions use the stream's current locale (specifically, the
+       *  @c num_get facet) to perform numeric formatting.
+      */
+      __ostream_type&
+      operator<<(long __n)
+      { return _M_insert(__n); }
+
+      __ostream_type&
+      operator<<(unsigned long __n)
+      { return _M_insert(__n); }
+
+      __ostream_type&
+      operator<<(bool __n)
+      { return _M_insert(__n); }
+
+      __ostream_type&
+      operator<<(short __n);
+
+      __ostream_type&
+      operator<<(unsigned short __n)
+      {
+	// _GLIBCXX_RESOLVE_LIB_DEFECTS
+	// 117. basic_ostream uses nonexistent num_put member functions.
+	return _M_insert(static_cast<unsigned long>(__n));
+      }
+
+      __ostream_type&
+      operator<<(int __n);
+
+      __ostream_type&
+      operator<<(unsigned int __n)
+      {
+	// _GLIBCXX_RESOLVE_LIB_DEFECTS
+	// 117. basic_ostream uses nonexistent num_put member functions.
+	return _M_insert(static_cast<unsigned long>(__n));
+      }
+
+#ifdef _GLIBCXX_USE_LONG_LONG
+      __ostream_type&
+      operator<<(long long __n)
+      { return _M_insert(__n); }
+
+      __ostream_type&
+      operator<<(unsigned long long __n)
+      { return _M_insert(__n); }
+#endif
+      ///@}
+
+      ///@{
+      /**
+       *  @brief  Floating point arithmetic inserters
+       *  @param  __f A variable of builtin floating point type.
+       *  @return  @c *this if successful
+       *
+       *  These functions use the stream's current locale (specifically, the
+       *  @c num_get facet) to perform numeric formatting.
+      */
+      __ostream_type&
+      operator<<(double __f)
+      { return _M_insert(__f); }
+
+      __ostream_type&
+      operator<<(float __f)
+      {
+	// _GLIBCXX_RESOLVE_LIB_DEFECTS
+	// 117. basic_ostream uses nonexistent num_put member functions.
+	return _M_insert(static_cast<double>(__f));
+      }
+
+      __ostream_type&
+      operator<<(long double __f)
+      { return _M_insert(__f); }
+      ///@}
+
+      /**
+       *  @brief  Pointer arithmetic inserters
+       *  @param  __p A variable of pointer type.
+       *  @return  @c *this if successful
+       *
+       *  These functions use the stream's current locale (specifically, the
+       *  @c num_get facet) to perform numeric formatting.
+      */
+      __ostream_type&
+      operator<<(const void* __p)
+      { return _M_insert(__p); }
+
+#if __cplusplus >= 201703L
+      __ostream_type&
+      operator<<(nullptr_t)
+      { return *this << "nullptr"; }
+#endif
+
+#if __cplusplus > 202002L
+      __attribute__((__always_inline__))
+      __ostream_type&
+      operator<<(const volatile void* __p)
+      { return _M_insert(const_cast<const void*>(__p)); }
+#endif
+
+      /**
+       *  @brief  Extracting from another streambuf.
+       *  @param  __sb  A pointer to a streambuf
+       *
+       *  This function behaves like one of the basic arithmetic extractors,
+       *  in that it also constructs a sentry object and has the same error
+       *  handling behavior.
+       *
+       *  If @p __sb is NULL, the stream will set failbit in its error state.
+       *
+       *  Characters are extracted from @p __sb and inserted into @c *this
+       *  until one of the following occurs:
+       *
+       *  - the input stream reaches end-of-file,
+       *  - insertion into the output sequence fails (in this case, the
+       *    character that would have been inserted is not extracted), or
+       *  - an exception occurs while getting a character from @p __sb, which
+       *    sets failbit in the error state
+       *
+       *  If the function inserts no characters, failbit is set.
+      */
+      __ostream_type&
+      operator<<(__streambuf_type* __sb);
+      ///@}
+
+      ///@{
+      /**
+       *  @name Unformatted Output Functions
+       *
+       *  All the unformatted output functions have some common behavior.
+       *  Each starts by constructing a temporary object of type
+       *  std::basic_ostream::sentry.  This has several effects, concluding
+       *  with the setting of a status flag; see the sentry documentation
+       *  for more.
+       *
+       *  If the sentry status is good, the function tries to generate
+       *  whatever data is appropriate for the type of the argument.
+       *
+       *  If an exception is thrown during insertion, ios_base::badbit
+       *  will be turned on in the stream's error state.  If badbit is on in
+       *  the stream's exceptions mask, the exception will be rethrown
+       *  without completing its actions.
+      */
+
+      /**
+       *  @brief  Simple insertion.
+       *  @param  __c  The character to insert.
+       *  @return  *this
+       *
+       *  Tries to insert @p __c.
+       *
+       *  @note  This function is not overloaded on signed char and
+       *         unsigned char.
+      */
+      __ostream_type&
+      put(char_type __c);
+
+      /**
+       *  @brief  Character string insertion.
+       *  @param  __s  The array to insert.
+       *  @param  __n  Maximum number of characters to insert.
+       *  @return  *this
+       *
+       *  Characters are copied from @p __s and inserted into the stream until
+       *  one of the following happens:
+       *
+       *  - @p __n characters are inserted
+       *  - inserting into the output sequence fails (in this case, badbit
+       *    will be set in the stream's error state)
+       *
+       *  @note  This function is not overloaded on signed char and
+       *         unsigned char.
+      */
+      __ostream_type&
+      write(const char_type* __s, streamsize __n);
+      ///@}
+
+      /**
+       *  @brief  Synchronizing the stream buffer.
+       *  @return  *this
+       *
+       *  If @c rdbuf() is a null pointer, changes nothing.
+       *
+       *  Otherwise, calls @c rdbuf()->pubsync(), and if that returns -1,
+       *  sets badbit.
+      */
+      __ostream_type&
+      flush();
+
+      /**
+       *  @brief  Getting the current write position.
+       *  @return  A file position object.
+       *
+       *  If @c fail() is not false, returns @c pos_type(-1) to indicate
+       *  failure.  Otherwise returns @c rdbuf()->pubseekoff(0,cur,out).
+      */
+      pos_type
+      tellp();
+
+      /**
+       *  @brief  Changing the current write position.
+       *  @param  __pos  A file position object.
+       *  @return  *this
+       *
+       *  If @c fail() is not true, calls @c rdbuf()->pubseekpos(pos).  If
+       *  that function fails, sets failbit.
+      */
+      __ostream_type&
+      seekp(pos_type);
+
+      /**
+       *  @brief  Changing the current write position.
+       *  @param  __off  A file offset object.
+       *  @param  __dir  The direction in which to seek.
+       *  @return  *this
+       *
+       *  If @c fail() is not true, calls @c rdbuf()->pubseekoff(off,dir).
+       *  If that function fails, sets failbit.
+      */
+       __ostream_type&
+      seekp(off_type, ios_base::seekdir);
+
+    protected:
+      basic_ostream()
+      { this->init(0); }
+
+#if __cplusplus >= 201103L
+      // Non-standard constructor that does not call init()
+      basic_ostream(basic_iostream<_CharT, _Traits>&) { }
+
+      basic_ostream(const basic_ostream&) = delete;
+
+      basic_ostream(basic_ostream&& __rhs)
+      : __ios_type()
+      { __ios_type::move(__rhs); }
+
+      // 27.7.3.3 Assign/swap
+
+      basic_ostream& operator=(const basic_ostream&) = delete;
+
+      basic_ostream&
+      operator=(basic_ostream&& __rhs)
+      {
+	swap(__rhs);
+	return *this;
+      }
+
+      void
+      swap(basic_ostream& __rhs)
+      { __ios_type::swap(__rhs); }
+#endif
+
+      template<typename _ValueT>
+	__ostream_type&
+	_M_insert(_ValueT __v);
+
+    private:
+#if !_GLIBCXX_INLINE_VERSION
+      void
+      _M_write(const char_type* __s, streamsize __n)
+      { std::__ostream_insert(*this, __s, __n); }
+#endif
+    };
+
+  /**
+   *  @brief  Performs setup work for output streams.
+   *
+   *  Objects of this class are created before all of the standard
+   *  inserters are run.  It is responsible for <em>exception-safe prefix and
+   *  suffix operations</em>.
+  */
+  template <typename _CharT, typename _Traits>
+    class basic_ostream<_CharT, _Traits>::sentry
+    {
+      // Data Members.
+      bool 				_M_ok;
+      basic_ostream<_CharT, _Traits>& 	_M_os;
+
+    public:
+      /**
+       *  @brief  The constructor performs preparatory work.
+       *  @param  __os  The output stream to guard.
+       *
+       *  If the stream state is good (@a __os.good() is true), then if the
+       *  stream is tied to another output stream, @c is.tie()->flush()
+       *  is called to synchronize the output sequences.
+       *
+       *  If the stream state is still good, then the sentry state becomes
+       *  true (@a okay).
+      */
+      explicit
+      sentry(basic_ostream<_CharT, _Traits>& __os);
+
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+      /**
+       *  @brief  Possibly flushes the stream.
+       *
+       *  If @c ios_base::unitbuf is set in @c os.flags(), and
+       *  @c std::uncaught_exception() is true, the sentry destructor calls
+       *  @c flush() on the output stream.
+      */
+      ~sentry()
+      {
+	// XXX MT
+	if (bool(_M_os.flags() & ios_base::unitbuf) && !uncaught_exception())
+	  {
+	    // Can't call flush directly or else will get into recursive lock.
+	    if (_M_os.rdbuf() && _M_os.rdbuf()->pubsync() == -1)
+	      _M_os.setstate(ios_base::badbit);
+	  }
+      }
+#pragma GCC diagnostic pop
+
+      /**
+       *  @brief  Quick status checking.
+       *  @return  The sentry state.
+       *
+       *  For ease of use, sentries may be converted to booleans.  The
+       *  return value is that of the sentry state (true == okay).
+      */
+#if __cplusplus >= 201103L
+      explicit
+#endif
+      operator bool() const
+      { return _M_ok; }
+    };
+
+  ///@{
+  /**
+   *  @brief  Character inserters
+   *  @param  __out  An output stream.
+   *  @param  __c  A character.
+   *  @return  out
+   *
+   *  Behaves like one of the formatted arithmetic inserters described in
+   *  std::basic_ostream.  After constructing a sentry object with good
+   *  status, this function inserts a single character and any required
+   *  padding (as determined by [22.2.2.2.2]).  @c __out.width(0) is then
+   *  called.
+   *
+   *  If @p __c is of type @c char and the character type of the stream is not
+   *  @c char, the character is widened before insertion.
+  */
+  template<typename _CharT, typename _Traits>
+    inline basic_ostream<_CharT, _Traits>&
+    operator<<(basic_ostream<_CharT, _Traits>& __out, _CharT __c)
+    {
+      if (__out.width() != 0)
+	return __ostream_insert(__out, &__c, 1);
+      __out.put(__c);
+      return __out;
+    }
+
+  template<typename _CharT, typename _Traits>
+    inline basic_ostream<_CharT, _Traits>&
+    operator<<(basic_ostream<_CharT, _Traits>& __out, char __c)
+    { return (__out << __out.widen(__c)); }
+
+  // Specialization
+  template<typename _Traits>
+    inline basic_ostream<char, _Traits>&
+    operator<<(basic_ostream<char, _Traits>& __out, char __c)
+    {
+      if (__out.width() != 0)
+	return __ostream_insert(__out, &__c, 1);
+      __out.put(__c);
+      return __out;
+    }
+
+  // Signed and unsigned
+  template<typename _Traits>
+    inline basic_ostream<char, _Traits>&
+    operator<<(basic_ostream<char, _Traits>& __out, signed char __c)
+    { return (__out << static_cast<char>(__c)); }
+
+  template<typename _Traits>
+    inline basic_ostream<char, _Traits>&
+    operator<<(basic_ostream<char, _Traits>& __out, unsigned char __c)
+    { return (__out << static_cast<char>(__c)); }
+
+#if __cplusplus > 201703L
+  // The following deleted overloads prevent formatting character values as
+  // numeric values.
+
+  template<typename _Traits>
+    basic_ostream<char, _Traits>&
+    operator<<(basic_ostream<char, _Traits>&, wchar_t) = delete;
+
+#ifdef _GLIBCXX_USE_CHAR8_T
+  template<typename _Traits>
+    basic_ostream<char, _Traits>&
+    operator<<(basic_ostream<char, _Traits>&, char8_t) = delete;
+#endif
+
+  template<typename _Traits>
+    basic_ostream<char, _Traits>&
+    operator<<(basic_ostream<char, _Traits>&, char16_t) = delete;
+
+  template<typename _Traits>
+    basic_ostream<char, _Traits>&
+    operator<<(basic_ostream<char, _Traits>&, char32_t) = delete;
+
+#ifdef _GLIBCXX_USE_WCHAR_T
+#ifdef _GLIBCXX_USE_CHAR8_T
+  template<typename _Traits>
+    basic_ostream<wchar_t, _Traits>&
+    operator<<(basic_ostream<wchar_t, _Traits>&, char8_t) = delete;
+#endif // _GLIBCXX_USE_CHAR8_T
+
+  template<typename _Traits>
+    basic_ostream<wchar_t, _Traits>&
+    operator<<(basic_ostream<wchar_t, _Traits>&, char16_t) = delete;
+
+  template<typename _Traits>
+    basic_ostream<wchar_t, _Traits>&
+    operator<<(basic_ostream<wchar_t, _Traits>&, char32_t) = delete;
+#endif // _GLIBCXX_USE_WCHAR_T
+#endif // C++20
+  ///@}
+
+  ///@{
+  /**
+   *  @brief  String inserters
+   *  @param  __out  An output stream.
+   *  @param  __s  A character string.
+   *  @return  out
+   *  @pre  @p __s must be a non-NULL pointer
+   *
+   *  Behaves like one of the formatted arithmetic inserters described in
+   *  std::basic_ostream.  After constructing a sentry object with good
+   *  status, this function inserts @c traits::length(__s) characters starting
+   *  at @p __s, widened if necessary, followed by any required padding (as
+   *  determined by [22.2.2.2.2]).  @c __out.width(0) is then called.
+  */
+  template<typename _CharT, typename _Traits>
+    inline basic_ostream<_CharT, _Traits>&
+    operator<<(basic_ostream<_CharT, _Traits>& __out, const _CharT* __s)
+    {
+      if (!__s)
+	__out.setstate(ios_base::badbit);
+      else
+	__ostream_insert(__out, __s,
+			 static_cast<streamsize>(_Traits::length(__s)));
+      return __out;
+    }
+
+  template<typename _CharT, typename _Traits>
+    basic_ostream<_CharT, _Traits> &
+    operator<<(basic_ostream<_CharT, _Traits>& __out, const char* __s);
+
+  // Partial specializations
+  template<typename _Traits>
+    inline basic_ostream<char, _Traits>&
+    operator<<(basic_ostream<char, _Traits>& __out, const char* __s)
+    {
+      if (!__s)
+	__out.setstate(ios_base::badbit);
+      else
+	__ostream_insert(__out, __s,
+			 static_cast<streamsize>(_Traits::length(__s)));
+      return __out;
+    }
+
+  // Signed and unsigned
+  template<typename _Traits>
+    inline basic_ostream<char, _Traits>&
+    operator<<(basic_ostream<char, _Traits>& __out, const signed char* __s)
+    { return (__out << reinterpret_cast<const char*>(__s)); }
+
+  template<typename _Traits>
+    inline basic_ostream<char, _Traits> &
+    operator<<(basic_ostream<char, _Traits>& __out, const unsigned char* __s)
+    { return (__out << reinterpret_cast<const char*>(__s)); }
+
+#if __cplusplus > 201703L
+   // The following deleted overloads prevent formatting strings as
+   // pointer values.
+
+  template<typename _Traits>
+    basic_ostream<char, _Traits>&
+    operator<<(basic_ostream<char, _Traits>&, const wchar_t*) = delete;
+
+#ifdef _GLIBCXX_USE_CHAR8_T
+  template<typename _Traits>
+    basic_ostream<char, _Traits>&
+    operator<<(basic_ostream<char, _Traits>&, const char8_t*) = delete;
+#endif // _GLIBCXX_USE_CHAR8_T
+
+  template<typename _Traits>
+    basic_ostream<char, _Traits>&
+    operator<<(basic_ostream<char, _Traits>&, const char16_t*) = delete;
+
+  template<typename _Traits>
+    basic_ostream<char, _Traits>&
+    operator<<(basic_ostream<char, _Traits>&, const char32_t*) = delete;
+
+#ifdef _GLIBCXX_USE_WCHAR_T
+#ifdef _GLIBCXX_USE_CHAR8_T
+  template<typename _Traits>
+    basic_ostream<wchar_t, _Traits>&
+    operator<<(basic_ostream<wchar_t, _Traits>&, const char8_t*) = delete;
+#endif
+
+  template<typename _Traits>
+    basic_ostream<wchar_t, _Traits>&
+    operator<<(basic_ostream<wchar_t, _Traits>&, const char16_t*) = delete;
+
+  template<typename _Traits>
+    basic_ostream<wchar_t, _Traits>&
+    operator<<(basic_ostream<wchar_t, _Traits>&, const char32_t*) = delete;
+#endif // _GLIBCXX_USE_WCHAR_T
+#endif // C++20
+  ///@}
+
+  // Standard basic_ostream manipulators
+
+  /**
+   *  @brief  Write a newline and flush the stream.
+   *
+   *  This manipulator is often mistakenly used when a simple newline is
+   *  desired, leading to poor buffering performance.  See
+   *  https://gcc.gnu.org/onlinedocs/libstdc++/manual/streambufs.html#io.streambuf.buffering
+   *  for more on this subject.
+  */
+  template<typename _CharT, typename _Traits>
+    inline basic_ostream<_CharT, _Traits>&
+    endl(basic_ostream<_CharT, _Traits>& __os)
+    { return flush(__os.put(__os.widen('\n'))); }
+
+  /**
+   *  @brief  Write a null character into the output sequence.
+   *
+   *  <em>Null character</em> is @c CharT() by definition.  For CharT
+   *  of @c char, this correctly writes the ASCII @c NUL character
+   *  string terminator.
+  */
+  template<typename _CharT, typename _Traits>
+    inline basic_ostream<_CharT, _Traits>&
+    ends(basic_ostream<_CharT, _Traits>& __os)
+    { return __os.put(_CharT()); }
+
+  /**
+   *  @brief  Flushes the output stream.
+   *
+   *  This manipulator simply calls the stream's @c flush() member function.
+  */
+  template<typename _CharT, typename _Traits>
+    inline basic_ostream<_CharT, _Traits>&
+    flush(basic_ostream<_CharT, _Traits>& __os)
+    { return __os.flush(); }
+
+#if __cplusplus >= 201103L
+  // C++11 27.7.3.9 Rvalue stream insertion [ostream.rvalue]
+  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+  // 1203. More useful rvalue stream insertion
+
+#if __cpp_lib_concepts
+  // Use concepts if possible because they're cheaper to evaluate.
+  template<typename _Tp>
+    concept __derived_from_ios_base = is_class_v<_Tp>
+      && (!is_same_v<_Tp, ios_base>)
+      && requires (_Tp* __t, ios_base* __b) { __b = __t; };
+
+  template<typename _Os, typename _Tp>
+    requires __derived_from_ios_base<_Os>
+      && requires (_Os& __os, const _Tp& __t) { __os << __t; }
+    using __rvalue_stream_insertion_t = _Os&&;
+#else
+  template<typename _Tp>
+    using _Require_derived_from_ios_base
+      = _Require<is_class<_Tp>, __not_<is_same<_Tp, ios_base>>,
+		 is_convertible<typename add_pointer<_Tp>::type, ios_base*>>;
+
+  template<typename _Os, typename _Tp,
+	   typename = _Require_derived_from_ios_base<_Os>,
+	   typename
+	     = decltype(std::declval<_Os&>() << std::declval<const _Tp&>())>
+    using __rvalue_stream_insertion_t = _Os&&;
+#endif
+
+  /**
+   *  @brief  Generic inserter for rvalue stream
+   *  @param  __os  An input stream.
+   *  @param  __x  A reference to the object being inserted.
+   *  @return  __os
+   *
+   *  This is just a forwarding function to allow insertion to
+   *  rvalue streams since they won't bind to the inserter functions
+   *  that take an lvalue reference.
+  */
+  template<typename _Ostream, typename _Tp>
+    inline __rvalue_stream_insertion_t<_Ostream, _Tp>
+    operator<<(_Ostream&& __os, const _Tp& __x)
+    {
+      __os << __x;
+      return std::move(__os);
+    }
+
+#if __cplusplus > 201703L && _GLIBCXX_USE_CXX11_ABI
+  template<typename _CharT, typename _Traits>
+    class __syncbuf_base : public basic_streambuf<_CharT, _Traits>
+    {
+    public:
+      static bool*
+      _S_get(basic_streambuf<_CharT, _Traits>* __buf [[maybe_unused]]) noexcept
+      {
+#if __cpp_rtti
+	if (auto __p = dynamic_cast<__syncbuf_base*>(__buf))
+	  return &__p->_M_emit_on_sync;
+#endif
+	return nullptr;
+      }
+
+    protected:
+      __syncbuf_base(basic_streambuf<_CharT, _Traits>* __w = nullptr)
+      : _M_wrapped(__w)
+      { }
+
+      basic_streambuf<_CharT, _Traits>* _M_wrapped = nullptr;
+      bool _M_emit_on_sync = false;
+      bool _M_needs_sync = false;
+    };
+
+  template<typename _CharT, typename _Traits>
+    inline basic_ostream<_CharT, _Traits>&
+    emit_on_flush(basic_ostream<_CharT, _Traits>& __os)
+    {
+      if (bool* __flag = __syncbuf_base<_CharT, _Traits>::_S_get(__os.rdbuf()))
+	*__flag = true;
+      return __os;
+    }
+
+  template<typename _CharT, typename _Traits>
+    inline basic_ostream<_CharT, _Traits>&
+    noemit_on_flush(basic_ostream<_CharT, _Traits>& __os)
+    {
+      if (bool* __flag = __syncbuf_base<_CharT, _Traits>::_S_get(__os.rdbuf()))
+	*__flag = false;
+      return __os;
+    }
+
+  template<typename _CharT, typename _Traits>
+    inline basic_ostream<_CharT, _Traits>&
+    flush_emit(basic_ostream<_CharT, _Traits>& __os)
+    {
+      struct _Restore
+      {
+	~_Restore() { *_M_flag = _M_prev; }
+
+	bool _M_prev = false;
+	bool* _M_flag = &_M_prev;
+      } __restore;
+
+      if (bool* __flag = __syncbuf_base<_CharT, _Traits>::_S_get(__os.rdbuf()))
+	{
+	  __restore._M_prev = *__flag;
+	  __restore._M_flag = __flag;
+	  *__flag = true;
+	}
+
+      __os.flush();
+      return __os;
+    }
+
+#endif // C++20
+
+#endif // C++11
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#include <bits/ostream.tcc>
+
+#endif	/* _GLIBCXX_OSTREAM */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@ostream.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@ostream.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@queue b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@queue
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@@ -0,0 +1,66 @@
+// <queue> -*- C++ -*-
+
+// Copyright (C) 2001-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/*
+ *
+ * Copyright (c) 1994
+ * Hewlett-Packard Company
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Hewlett-Packard Company makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ *
+ *
+ * Copyright (c) 1996,1997
+ * Silicon Graphics Computer Systems, Inc.
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Silicon Graphics makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ */
+
+/** @file include/queue
+ *  This is a Standard C++ Library header.
+ */
+
+#ifndef _GLIBCXX_QUEUE
+#define _GLIBCXX_QUEUE 1
+
+#pragma GCC system_header
+
+#include <deque>
+#include <vector>
+#include <bits/stl_heap.h>
+#include <bits/stl_function.h>
+#include <bits/stl_queue.h>
+
+#endif /* _GLIBCXX_QUEUE */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@queue.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@queue.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@random b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@random
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index 0000000000000000000000000000000000000000..89a2f16c9217b502ed24a31ca831c4938814d36c
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@random
@@ -0,0 +1,57 @@
+// <random> -*- C++ -*-
+
+// Copyright (C) 2007-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file include/random
+ *  This is a Standard C++ Library header.
+ */
+
+#ifndef _GLIBCXX_RANDOM
+#define _GLIBCXX_RANDOM 1
+
+#pragma GCC system_header
+
+#if __cplusplus < 201103L
+# include <bits/c++0x_warning.h>
+#else
+
+#include <cmath>
+#include <cstdlib>
+#include <string>
+#include <iosfwd>
+#include <limits>
+#include <debug/debug.h>
+#include <type_traits>
+
+#ifdef _GLIBCXX_USE_C99_STDINT_TR1
+
+#include <cstdint> // For uint_fast32_t, uint_fast64_t, uint_least32_t
+#include <bits/random.h>
+#include <bits/opt_random.h>
+#include <bits/random.tcc>
+
+#endif // _GLIBCXX_USE_C99_STDINT_TR1
+
+#endif // C++11
+
+#endif // _GLIBCXX_RANDOM
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@ratio b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@ratio
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--- /dev/null
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@@ -0,0 +1,586 @@
+// ratio -*- C++ -*-
+
+// Copyright (C) 2008-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file include/ratio
+ *  This is a Standard C++ Library header.
+ *  @ingroup ratio
+ */
+
+#ifndef _GLIBCXX_RATIO
+#define _GLIBCXX_RATIO 1
+
+#pragma GCC system_header
+
+#if __cplusplus < 201103L
+# include <bits/c++0x_warning.h>
+#else
+
+#include <type_traits>
+#include <cstdint>		// intmax_t, uintmax_t
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /**
+   * @defgroup ratio Rational Arithmetic
+   * @ingroup utilities
+   *
+   * Compile time representation of finite rational numbers.
+   * @{
+   */
+
+  /// @cond undocumented
+
+  template<intmax_t _Pn>
+    struct __static_sign
+    : integral_constant<intmax_t, (_Pn < 0) ? -1 : 1>
+    { };
+
+  template<intmax_t _Pn>
+    struct __static_abs
+    : integral_constant<intmax_t, _Pn * __static_sign<_Pn>::value>
+    { };
+
+  template<intmax_t _Pn, intmax_t _Qn>
+    struct __static_gcd
+    : __static_gcd<_Qn, (_Pn % _Qn)>
+    { };
+
+  template<intmax_t _Pn>
+    struct __static_gcd<_Pn, 0>
+    : integral_constant<intmax_t, __static_abs<_Pn>::value>
+    { };
+
+  template<intmax_t _Qn>
+    struct __static_gcd<0, _Qn>
+    : integral_constant<intmax_t, __static_abs<_Qn>::value>
+    { };
+
+  // Let c = 2^(half # of bits in an intmax_t)
+  // then we find a1, a0, b1, b0 s.t. N = a1*c + a0, M = b1*c + b0
+  // The multiplication of N and M becomes,
+  // N * M = (a1 * b1)c^2 + (a0 * b1 + b0 * a1)c + a0 * b0
+  // Multiplication is safe if each term and the sum of the terms
+  // is representable by intmax_t.
+  template<intmax_t _Pn, intmax_t _Qn>
+    struct __safe_multiply
+    {
+    private:
+      static const uintmax_t __c = uintmax_t(1) << (sizeof(intmax_t) * 4);
+
+      static const uintmax_t __a0 = __static_abs<_Pn>::value % __c;
+      static const uintmax_t __a1 = __static_abs<_Pn>::value / __c;
+      static const uintmax_t __b0 = __static_abs<_Qn>::value % __c;
+      static const uintmax_t __b1 = __static_abs<_Qn>::value / __c;
+
+      static_assert(__a1 == 0 || __b1 == 0,
+		    "overflow in multiplication");
+      static_assert(__a0 * __b1 + __b0 * __a1 < (__c >> 1),
+		    "overflow in multiplication");
+      static_assert(__b0 * __a0 <= __INTMAX_MAX__,
+		    "overflow in multiplication");
+      static_assert((__a0 * __b1 + __b0 * __a1) * __c
+		    <= __INTMAX_MAX__ -  __b0 * __a0,
+		    "overflow in multiplication");
+
+    public:
+      static const intmax_t value = _Pn * _Qn;
+    };
+
+  // Some double-precision utilities, where numbers are represented as
+  // __hi*2^(8*sizeof(uintmax_t)) + __lo.
+  template<uintmax_t __hi1, uintmax_t __lo1, uintmax_t __hi2, uintmax_t __lo2>
+    struct __big_less
+    : integral_constant<bool, (__hi1 < __hi2
+			       || (__hi1 == __hi2 && __lo1 < __lo2))>
+    { };
+
+  template<uintmax_t __hi1, uintmax_t __lo1, uintmax_t __hi2, uintmax_t __lo2>
+    struct __big_add
+    {
+      static constexpr uintmax_t __lo = __lo1 + __lo2;
+      static constexpr uintmax_t __hi = (__hi1 + __hi2 +
+					 (__lo1 + __lo2 < __lo1)); // carry
+    };
+
+  // Subtract a number from a bigger one.
+  template<uintmax_t __hi1, uintmax_t __lo1, uintmax_t __hi2, uintmax_t __lo2>
+    struct __big_sub
+    {
+      static_assert(!__big_less<__hi1, __lo1, __hi2, __lo2>::value,
+		    "Internal library error");
+      static constexpr uintmax_t __lo = __lo1 - __lo2;
+      static constexpr uintmax_t __hi = (__hi1 - __hi2 -
+					 (__lo1 < __lo2)); // carry
+    };
+
+  // Same principle as __safe_multiply.
+  template<uintmax_t __x, uintmax_t __y>
+    struct __big_mul
+    {
+    private:
+      static constexpr uintmax_t __c = uintmax_t(1) << (sizeof(intmax_t) * 4);
+      static constexpr uintmax_t __x0 = __x % __c;
+      static constexpr uintmax_t __x1 = __x / __c;
+      static constexpr uintmax_t __y0 = __y % __c;
+      static constexpr uintmax_t __y1 = __y / __c;
+      static constexpr uintmax_t __x0y0 = __x0 * __y0;
+      static constexpr uintmax_t __x0y1 = __x0 * __y1;
+      static constexpr uintmax_t __x1y0 = __x1 * __y0;
+      static constexpr uintmax_t __x1y1 = __x1 * __y1;
+      static constexpr uintmax_t __mix = __x0y1 + __x1y0; // possible carry...
+      static constexpr uintmax_t __mix_lo = __mix * __c;
+      static constexpr uintmax_t __mix_hi
+      = __mix / __c + ((__mix < __x0y1) ? __c : 0); // ... added here
+      typedef __big_add<__mix_hi, __mix_lo, __x1y1, __x0y0> _Res;
+    public:
+      static constexpr uintmax_t __hi = _Res::__hi;
+      static constexpr uintmax_t __lo = _Res::__lo;
+    };
+
+  // Adapted from __udiv_qrnnd_c in longlong.h
+  // This version assumes that the high bit of __d is 1.
+  template<uintmax_t __n1, uintmax_t __n0, uintmax_t __d>
+    struct __big_div_impl
+    {
+    private:
+      static_assert(__d >= (uintmax_t(1) << (sizeof(intmax_t) * 8 - 1)),
+		    "Internal library error");
+      static_assert(__n1 < __d, "Internal library error");
+      static constexpr uintmax_t __c = uintmax_t(1) << (sizeof(intmax_t) * 4);
+      static constexpr uintmax_t __d1 = __d / __c;
+      static constexpr uintmax_t __d0 = __d % __c;
+
+      static constexpr uintmax_t __q1x = __n1 / __d1;
+      static constexpr uintmax_t __r1x = __n1 % __d1;
+      static constexpr uintmax_t __m = __q1x * __d0;
+      static constexpr uintmax_t __r1y = __r1x * __c + __n0 / __c;
+      static constexpr uintmax_t __r1z = __r1y + __d;
+      static constexpr uintmax_t __r1
+      = ((__r1y < __m) ? ((__r1z >= __d) && (__r1z < __m))
+	 ? (__r1z + __d) : __r1z : __r1y) - __m;
+      static constexpr uintmax_t __q1
+      = __q1x - ((__r1y < __m)
+		 ? ((__r1z >= __d) && (__r1z < __m)) ? 2 : 1 : 0);
+      static constexpr uintmax_t __q0x = __r1 / __d1;
+      static constexpr uintmax_t __r0x = __r1 % __d1;
+      static constexpr uintmax_t __n = __q0x * __d0;
+      static constexpr uintmax_t __r0y = __r0x * __c + __n0 % __c;
+      static constexpr uintmax_t __r0z = __r0y + __d;
+      static constexpr uintmax_t __r0
+      = ((__r0y < __n) ? ((__r0z >= __d) && (__r0z < __n))
+	 ? (__r0z + __d) : __r0z : __r0y) - __n;
+      static constexpr uintmax_t __q0
+      = __q0x - ((__r0y < __n) ? ((__r0z >= __d)
+				  && (__r0z < __n)) ? 2 : 1 : 0);
+
+    public:
+      static constexpr uintmax_t __quot = __q1 * __c + __q0;
+      static constexpr uintmax_t __rem = __r0;
+
+    private:
+      typedef __big_mul<__quot, __d> _Prod;
+      typedef __big_add<_Prod::__hi, _Prod::__lo, 0, __rem> _Sum;
+      static_assert(_Sum::__hi == __n1 && _Sum::__lo == __n0,
+		    "Internal library error");
+  };
+
+  template<uintmax_t __n1, uintmax_t __n0, uintmax_t __d>
+    struct __big_div
+    {
+    private:
+      static_assert(__d != 0, "Internal library error");
+      static_assert(sizeof (uintmax_t) == sizeof (unsigned long long),
+		    "This library calls __builtin_clzll on uintmax_t, which "
+		    "is unsafe on your platform. Please complain to "
+		    "http://gcc.gnu.org/bugzilla/");
+      static constexpr int __shift = __builtin_clzll(__d);
+      static constexpr int __coshift_ = sizeof(uintmax_t) * 8 - __shift;
+      static constexpr int __coshift = (__shift != 0) ? __coshift_ : 0;
+      static constexpr uintmax_t __c1 = uintmax_t(1) << __shift;
+      static constexpr uintmax_t __c2 = uintmax_t(1) << __coshift;
+      static constexpr uintmax_t __new_d = __d * __c1;
+      static constexpr uintmax_t __new_n0 = __n0 * __c1;
+      static constexpr uintmax_t __n1_shifted = (__n1 % __d) * __c1;
+      static constexpr uintmax_t __n0_top = (__shift != 0) ? (__n0 / __c2) : 0;
+      static constexpr uintmax_t __new_n1 = __n1_shifted + __n0_top;
+      typedef __big_div_impl<__new_n1, __new_n0, __new_d> _Res;
+
+    public:
+      static constexpr uintmax_t __quot_hi = __n1 / __d;
+      static constexpr uintmax_t __quot_lo = _Res::__quot;
+      static constexpr uintmax_t __rem = _Res::__rem / __c1;
+
+    private:
+      typedef __big_mul<__quot_lo, __d> _P0;
+      typedef __big_mul<__quot_hi, __d> _P1;
+      typedef __big_add<_P0::__hi, _P0::__lo, _P1::__lo, __rem> _Sum;
+      // No overflow.
+      static_assert(_P1::__hi == 0, "Internal library error");
+      static_assert(_Sum::__hi >= _P0::__hi, "Internal library error");
+      // Matches the input data.
+      static_assert(_Sum::__hi == __n1 && _Sum::__lo == __n0,
+		    "Internal library error");
+      static_assert(__rem < __d, "Internal library error");
+    };
+
+  /// @endcond
+
+  /**
+   *  @brief Provides compile-time rational arithmetic.
+   *
+   *  This class template represents any finite rational number with a
+   *  numerator and denominator representable by compile-time constants of
+   *  type intmax_t. The ratio is simplified when instantiated.
+   *
+   *  For example:
+   *  @code
+   *    std::ratio<7,-21>::num == -1;
+   *    std::ratio<7,-21>::den == 3;
+   *  @endcode
+   *
+  */
+  template<intmax_t _Num, intmax_t _Den = 1>
+    struct ratio
+    {
+      static_assert(_Den != 0, "denominator cannot be zero");
+      static_assert(_Num >= -__INTMAX_MAX__ && _Den >= -__INTMAX_MAX__,
+		    "out of range");
+
+      // Note: sign(N) * abs(N) == N
+      static constexpr intmax_t num =
+        _Num * __static_sign<_Den>::value / __static_gcd<_Num, _Den>::value;
+
+      static constexpr intmax_t den =
+        __static_abs<_Den>::value / __static_gcd<_Num, _Den>::value;
+
+      typedef ratio<num, den> type;
+    };
+
+#if ! __cpp_inline_variables
+  template<intmax_t _Num, intmax_t _Den>
+    constexpr intmax_t ratio<_Num, _Den>::num;
+
+  template<intmax_t _Num, intmax_t _Den>
+    constexpr intmax_t ratio<_Num, _Den>::den;
+#endif
+
+  /// @cond undocumented
+
+  template<typename _R1, typename _R2>
+    struct __ratio_multiply
+    {
+    private:
+      static const intmax_t __gcd1 =
+        __static_gcd<_R1::num, _R2::den>::value;
+      static const intmax_t __gcd2 =
+        __static_gcd<_R2::num, _R1::den>::value;
+
+    public:
+      typedef ratio<
+        __safe_multiply<(_R1::num / __gcd1),
+                        (_R2::num / __gcd2)>::value,
+        __safe_multiply<(_R1::den / __gcd2),
+                        (_R2::den / __gcd1)>::value> type;
+
+      static constexpr intmax_t num = type::num;
+      static constexpr intmax_t den = type::den;
+    };
+
+#if ! __cpp_inline_variables
+  template<typename _R1, typename _R2>
+    constexpr intmax_t __ratio_multiply<_R1, _R2>::num;
+
+  template<typename _R1, typename _R2>
+    constexpr intmax_t __ratio_multiply<_R1, _R2>::den;
+#endif
+
+  /// @endcond
+
+  /// ratio_multiply
+  template<typename _R1, typename _R2>
+    using ratio_multiply = typename __ratio_multiply<_R1, _R2>::type;
+
+  /// @cond undocumented
+
+  template<typename _R1, typename _R2>
+    struct __ratio_divide
+    {
+      static_assert(_R2::num != 0, "division by 0");
+
+      typedef typename __ratio_multiply<
+        _R1,
+        ratio<_R2::den, _R2::num>>::type type;
+
+      static constexpr intmax_t num = type::num;
+      static constexpr intmax_t den = type::den;
+    };
+
+#if ! __cpp_inline_variables
+  template<typename _R1, typename _R2>
+    constexpr intmax_t __ratio_divide<_R1, _R2>::num;
+
+  template<typename _R1, typename _R2>
+    constexpr intmax_t __ratio_divide<_R1, _R2>::den;
+#endif
+
+  /// @endcond
+
+  /// ratio_divide
+  template<typename _R1, typename _R2>
+    using ratio_divide = typename __ratio_divide<_R1, _R2>::type;
+
+  /// ratio_equal
+  template<typename _R1, typename _R2>
+    struct ratio_equal
+    : integral_constant<bool, _R1::num == _R2::num && _R1::den == _R2::den>
+    { };
+
+  /// ratio_not_equal
+  template<typename _R1, typename _R2>
+    struct ratio_not_equal
+    : integral_constant<bool, !ratio_equal<_R1, _R2>::value>
+    { };
+
+  /// @cond undocumented
+
+  // Both numbers are positive.
+  template<typename _R1, typename _R2,
+           typename _Left = __big_mul<_R1::num,_R2::den>,
+           typename _Right = __big_mul<_R2::num,_R1::den> >
+    struct __ratio_less_impl_1
+    : integral_constant<bool, __big_less<_Left::__hi, _Left::__lo,
+           _Right::__hi, _Right::__lo>::value>
+    { };
+
+  template<typename _R1, typename _R2,
+	   bool = (_R1::num == 0 || _R2::num == 0
+		   || (__static_sign<_R1::num>::value
+		       != __static_sign<_R2::num>::value)),
+	   bool = (__static_sign<_R1::num>::value == -1
+		   && __static_sign<_R2::num>::value == -1)>
+    struct __ratio_less_impl
+    : __ratio_less_impl_1<_R1, _R2>::type
+    { };
+
+  template<typename _R1, typename _R2>
+    struct __ratio_less_impl<_R1, _R2, true, false>
+    : integral_constant<bool, _R1::num < _R2::num>
+    { };
+
+  template<typename _R1, typename _R2>
+    struct __ratio_less_impl<_R1, _R2, false, true>
+    : __ratio_less_impl_1<ratio<-_R2::num, _R2::den>,
+           ratio<-_R1::num, _R1::den> >::type
+    { };
+
+  /// @endcond
+
+  /// ratio_less
+  template<typename _R1, typename _R2>
+    struct ratio_less
+    : __ratio_less_impl<_R1, _R2>::type
+    { };
+
+  /// ratio_less_equal
+  template<typename _R1, typename _R2>
+    struct ratio_less_equal
+    : integral_constant<bool, !ratio_less<_R2, _R1>::value>
+    { };
+
+  /// ratio_greater
+  template<typename _R1, typename _R2>
+    struct ratio_greater
+    : integral_constant<bool, ratio_less<_R2, _R1>::value>
+    { };
+
+  /// ratio_greater_equal
+  template<typename _R1, typename _R2>
+    struct ratio_greater_equal
+    : integral_constant<bool, !ratio_less<_R1, _R2>::value>
+    { };
+
+#if __cplusplus > 201402L
+  template <typename _R1, typename _R2>
+    inline constexpr bool ratio_equal_v = ratio_equal<_R1, _R2>::value;
+  template <typename _R1, typename _R2>
+    inline constexpr bool ratio_not_equal_v = ratio_not_equal<_R1, _R2>::value;
+  template <typename _R1, typename _R2>
+    inline constexpr bool ratio_less_v = ratio_less<_R1, _R2>::value;
+  template <typename _R1, typename _R2>
+    inline constexpr bool ratio_less_equal_v =
+      ratio_less_equal<_R1, _R2>::value;
+  template <typename _R1, typename _R2>
+    inline constexpr bool ratio_greater_v = ratio_greater<_R1, _R2>::value;
+  template <typename _R1, typename _R2>
+    inline constexpr bool ratio_greater_equal_v
+    = ratio_greater_equal<_R1, _R2>::value;
+#endif // C++17
+
+  /// @cond undocumented
+
+  template<typename _R1, typename _R2,
+      bool = (_R1::num >= 0),
+      bool = (_R2::num >= 0),
+      bool = ratio_less<ratio<__static_abs<_R1::num>::value, _R1::den>,
+        ratio<__static_abs<_R2::num>::value, _R2::den> >::value>
+    struct __ratio_add_impl
+    {
+    private:
+      typedef typename __ratio_add_impl<
+        ratio<-_R1::num, _R1::den>,
+        ratio<-_R2::num, _R2::den> >::type __t;
+    public:
+      typedef ratio<-__t::num, __t::den> type;
+    };
+
+  // True addition of nonnegative numbers.
+  template<typename _R1, typename _R2, bool __b>
+    struct __ratio_add_impl<_R1, _R2, true, true, __b>
+    {
+    private:
+      static constexpr uintmax_t __g = __static_gcd<_R1::den, _R2::den>::value;
+      static constexpr uintmax_t __d2 = _R2::den / __g;
+      typedef __big_mul<_R1::den, __d2> __d;
+      typedef __big_mul<_R1::num, _R2::den / __g> __x;
+      typedef __big_mul<_R2::num, _R1::den / __g> __y;
+      typedef __big_add<__x::__hi, __x::__lo, __y::__hi, __y::__lo> __n;
+      static_assert(__n::__hi >= __x::__hi, "Internal library error");
+      typedef __big_div<__n::__hi, __n::__lo, __g> __ng;
+      static constexpr uintmax_t __g2 = __static_gcd<__ng::__rem, __g>::value;
+      typedef __big_div<__n::__hi, __n::__lo, __g2> __n_final;
+      static_assert(__n_final::__rem == 0, "Internal library error");
+      static_assert(__n_final::__quot_hi == 0 &&
+        __n_final::__quot_lo <= __INTMAX_MAX__, "overflow in addition");
+      typedef __big_mul<_R1::den / __g2, __d2> __d_final;
+      static_assert(__d_final::__hi == 0 &&
+        __d_final::__lo <= __INTMAX_MAX__, "overflow in addition");
+    public:
+      typedef ratio<__n_final::__quot_lo, __d_final::__lo> type;
+    };
+
+  template<typename _R1, typename _R2>
+    struct __ratio_add_impl<_R1, _R2, false, true, true>
+    : __ratio_add_impl<_R2, _R1>
+    { };
+
+  // True subtraction of nonnegative numbers yielding a nonnegative result.
+  template<typename _R1, typename _R2>
+    struct __ratio_add_impl<_R1, _R2, true, false, false>
+    {
+    private:
+      static constexpr uintmax_t __g = __static_gcd<_R1::den, _R2::den>::value;
+      static constexpr uintmax_t __d2 = _R2::den / __g;
+      typedef __big_mul<_R1::den, __d2> __d;
+      typedef __big_mul<_R1::num, _R2::den / __g> __x;
+      typedef __big_mul<-_R2::num, _R1::den / __g> __y;
+      typedef __big_sub<__x::__hi, __x::__lo, __y::__hi, __y::__lo> __n;
+      typedef __big_div<__n::__hi, __n::__lo, __g> __ng;
+      static constexpr uintmax_t __g2 = __static_gcd<__ng::__rem, __g>::value;
+      typedef __big_div<__n::__hi, __n::__lo, __g2> __n_final;
+      static_assert(__n_final::__rem == 0, "Internal library error");
+      static_assert(__n_final::__quot_hi == 0 &&
+        __n_final::__quot_lo <= __INTMAX_MAX__, "overflow in addition");
+      typedef __big_mul<_R1::den / __g2, __d2> __d_final;
+      static_assert(__d_final::__hi == 0 &&
+        __d_final::__lo <= __INTMAX_MAX__, "overflow in addition");
+    public:
+      typedef ratio<__n_final::__quot_lo, __d_final::__lo> type;
+    };
+
+  template<typename _R1, typename _R2>
+    struct __ratio_add
+    {
+      typedef typename __ratio_add_impl<_R1, _R2>::type type;
+      static constexpr intmax_t num = type::num;
+      static constexpr intmax_t den = type::den;
+    };
+
+#if ! __cpp_inline_variables
+  template<typename _R1, typename _R2>
+    constexpr intmax_t __ratio_add<_R1, _R2>::num;
+
+  template<typename _R1, typename _R2>
+    constexpr intmax_t __ratio_add<_R1, _R2>::den;
+#endif
+
+  /// @endcond
+
+  /// ratio_add
+  template<typename _R1, typename _R2>
+    using ratio_add = typename __ratio_add<_R1, _R2>::type;
+
+  /// @cond undocumented
+
+  template<typename _R1, typename _R2>
+    struct __ratio_subtract
+    {
+      typedef typename __ratio_add<
+        _R1,
+        ratio<-_R2::num, _R2::den>>::type type;
+
+      static constexpr intmax_t num = type::num;
+      static constexpr intmax_t den = type::den;
+    };
+
+#if ! __cpp_inline_variables
+  template<typename _R1, typename _R2>
+    constexpr intmax_t __ratio_subtract<_R1, _R2>::num;
+
+  template<typename _R1, typename _R2>
+    constexpr intmax_t __ratio_subtract<_R1, _R2>::den;
+#endif
+
+  /// @endcond
+
+  /// ratio_subtract
+  template<typename _R1, typename _R2>
+    using ratio_subtract = typename __ratio_subtract<_R1, _R2>::type;
+
+
+  typedef ratio<1,       1000000000000000000> atto;
+  typedef ratio<1,          1000000000000000> femto;
+  typedef ratio<1,             1000000000000> pico;
+  typedef ratio<1,                1000000000> nano;
+  typedef ratio<1,                   1000000> micro;
+  typedef ratio<1,                      1000> milli;
+  typedef ratio<1,                       100> centi;
+  typedef ratio<1,                        10> deci;
+  typedef ratio<                       10, 1> deca;
+  typedef ratio<                      100, 1> hecto;
+  typedef ratio<                     1000, 1> kilo;
+  typedef ratio<                  1000000, 1> mega;
+  typedef ratio<               1000000000, 1> giga;
+  typedef ratio<            1000000000000, 1> tera;
+  typedef ratio<         1000000000000000, 1> peta;
+  typedef ratio<      1000000000000000000, 1> exa;
+
+  /// @} group ratio
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif // C++11
+
+#endif //_GLIBCXX_RATIO
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@ratio.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@ratio.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@regex b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@regex
new file mode 100644
index 0000000000000000000000000000000000000000..d1b6a6c68c362c058cd770b1802aad30a460f3d7
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@regex
@@ -0,0 +1,96 @@
+// <regex> -*- C++ -*-
+
+// Copyright (C) 2007-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file include/regex
+ *  This is a Standard C++ Library header.
+ */
+
+#ifndef _GLIBCXX_REGEX
+#define _GLIBCXX_REGEX 1
+
+#pragma GCC system_header
+
+#if __cplusplus < 201103L
+# include <bits/c++0x_warning.h>
+#else
+
+#include <bitset>
+#include <locale>
+#include <sstream>
+#include <stack>
+#include <stdexcept>
+#include <string>
+
+#include <ext/aligned_buffer.h>
+#include <ext/numeric_traits.h>
+#include <bits/shared_ptr.h>
+#include <bits/std_function.h>
+#include <bits/stl_algobase.h> // std::copy, std::fill_n
+#include <bits/stl_algo.h>     // std::sort, std::unique
+#include <bits/stl_iterator_base_types.h> // std::iterator_traits
+#include <bits/stl_pair.h>
+#include <bits/stl_tree.h>
+#include <bits/stl_map.h>
+#include <bits/stl_vector.h>
+#include <bits/stl_bvector.h>
+#include <bits/vector.tcc>
+#ifdef _GLIBCXX_DEBUG
+# include <debug/vector>
+#endif
+#include <bits/regex_constants.h>
+#include <bits/regex_error.h>
+#include <bits/regex_automaton.h>
+#include <bits/regex_scanner.h>
+#include <bits/regex_compiler.h>
+#include <bits/regex.h>
+#include <bits/regex_executor.h>
+
+#if __cplusplus >= 201703L && _GLIBCXX_USE_CXX11_ABI
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+  namespace pmr
+  {
+    template<typename _Tp> class polymorphic_allocator;
+    template<typename _BidirectionalIterator>
+      using match_results
+	= std::match_results<_BidirectionalIterator, polymorphic_allocator<
+				sub_match<_BidirectionalIterator>>>;
+    using cmatch = match_results<const char*>;
+    // Use __normal_iterator directly, because pmr::string::const_iterator
+    // would require pmr::polymorphic_allocator to be complete.
+    using smatch
+      = match_results<__gnu_cxx::__normal_iterator<const char*, string>>;
+#ifdef _GLIBCXX_USE_WCHAR_T
+    using wcmatch = match_results<const wchar_t*>;
+    using wsmatch
+      = match_results<__gnu_cxx::__normal_iterator<const wchar_t*, wstring>>;
+#endif
+  } // namespace pmr
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+#endif // C++17
+#endif // C++11
+
+#endif // _GLIBCXX_REGEX
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@regex.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@regex.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@scoped_allocator b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@scoped_allocator
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--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@scoped_allocator
@@ -0,0 +1,522 @@
+// <scoped_allocator> -*- C++ -*-
+
+// Copyright (C) 2011-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file include/scoped_allocator
+ *  This is a Standard C++ Library header.
+ *  @ingroup allocators
+ */
+
+#ifndef _SCOPED_ALLOCATOR
+#define _SCOPED_ALLOCATOR 1
+
+#pragma GCC system_header
+
+#if __cplusplus < 201103L
+# include <bits/c++0x_warning.h>
+#else
+
+#include <tuple>
+#include <bits/alloc_traits.h>
+#include <bits/stl_pair.h>
+#include <bits/uses_allocator.h>
+#if __cplusplus > 201703L
+# include <bits/uses_allocator_args.h>
+#endif
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /**
+   * @addtogroup allocators
+   * @{
+   */
+
+  template<typename _OuterAlloc, typename... _InnerAllocs>
+    class scoped_allocator_adaptor;
+
+  /// @cond undocumented
+
+  template<typename _Alloc>
+    using __outer_allocator_t
+      = decltype(std::declval<_Alloc>().outer_allocator());
+
+  template<typename _Alloc, typename = void>
+    struct __outermost_type
+    {
+      using type = _Alloc;
+      static type& _S_outermost(_Alloc& __a) { return __a; }
+    };
+
+  template<typename _Alloc>
+    struct __outermost_type<_Alloc, __void_t<__outer_allocator_t<_Alloc>>>
+    : __outermost_type<
+      typename remove_reference<__outer_allocator_t<_Alloc>>::type
+    >
+    {
+      using __base = __outermost_type<
+        typename remove_reference<__outer_allocator_t<_Alloc>>::type
+      >;
+
+      static typename __base::type&
+      _S_outermost(_Alloc& __a)
+      { return __base::_S_outermost(__a.outer_allocator()); }
+    };
+
+  // Implementation of the OUTERMOST pseudofunction
+  template<typename _Alloc>
+    inline typename __outermost_type<_Alloc>::type&
+    __outermost(_Alloc& __a)
+    { return __outermost_type<_Alloc>::_S_outermost(__a); }
+
+  template<typename...>
+    struct __inner_type_impl;
+
+  template<typename _Outer>
+    struct __inner_type_impl<_Outer>
+    {
+      typedef scoped_allocator_adaptor<_Outer> __type;
+
+      __inner_type_impl() = default;
+      __inner_type_impl(const __inner_type_impl&) = default;
+      __inner_type_impl(__inner_type_impl&&) = default;
+      __inner_type_impl& operator=(const __inner_type_impl&) = default;
+      __inner_type_impl& operator=(__inner_type_impl&&) = default;
+
+      template<typename _Alloc>
+      __inner_type_impl(const __inner_type_impl<_Alloc>& __other)
+      { }
+
+      template<typename _Alloc>
+      __inner_type_impl(__inner_type_impl<_Alloc>&& __other)
+      { }
+
+      __type&
+      _M_get(__type* __p) noexcept { return *__p; }
+
+      const __type&
+      _M_get(const __type* __p) const noexcept { return *__p; }
+
+      tuple<>
+      _M_tie() const noexcept { return tuple<>(); }
+
+      bool
+      operator==(const __inner_type_impl&) const noexcept
+      { return true; }
+    };
+
+  template<typename _Outer, typename _InnerHead, typename... _InnerTail>
+    struct __inner_type_impl<_Outer, _InnerHead, _InnerTail...>
+    {
+      typedef scoped_allocator_adaptor<_InnerHead, _InnerTail...> __type;
+
+      __inner_type_impl() = default;
+      __inner_type_impl(const __inner_type_impl&) = default;
+      __inner_type_impl(__inner_type_impl&&) = default;
+      __inner_type_impl& operator=(const __inner_type_impl&) = default;
+      __inner_type_impl& operator=(__inner_type_impl&&) = default;
+
+      template<typename... _Allocs>
+      __inner_type_impl(const __inner_type_impl<_Allocs...>& __other)
+      : _M_inner(__other._M_inner) { }
+
+      template<typename... _Allocs>
+      __inner_type_impl(__inner_type_impl<_Allocs...>&& __other)
+      : _M_inner(std::move(__other._M_inner)) { }
+
+    template<typename... _Args>
+      explicit
+      __inner_type_impl(_Args&&... __args)
+      : _M_inner(std::forward<_Args>(__args)...) { }
+
+      __type&
+      _M_get(void*) noexcept { return _M_inner; }
+
+      const __type&
+      _M_get(const void*) const noexcept { return _M_inner; }
+
+      tuple<const _InnerHead&, const _InnerTail&...>
+      _M_tie() const noexcept
+      { return _M_inner._M_tie(); }
+
+      bool
+      operator==(const __inner_type_impl& __other) const noexcept
+      { return _M_inner == __other._M_inner; }
+
+    private:
+      template<typename...> friend class __inner_type_impl;
+      template<typename, typename...> friend class scoped_allocator_adaptor;
+
+      __type _M_inner;
+    };
+
+  /// @endcond
+
+  /// An adaptor to recursively pass an allocator to the objects it constructs
+  template<typename _OuterAlloc, typename... _InnerAllocs>
+    class scoped_allocator_adaptor
+    : public _OuterAlloc
+    {
+      typedef allocator_traits<_OuterAlloc> __traits;
+
+      typedef __inner_type_impl<_OuterAlloc, _InnerAllocs...> __inner_type;
+      __inner_type _M_inner;
+
+      template<typename _Outer, typename... _Inner>
+        friend class scoped_allocator_adaptor;
+
+      template<typename...>
+        friend class __inner_type_impl;
+
+      tuple<const _OuterAlloc&, const _InnerAllocs&...>
+      _M_tie() const noexcept
+      { return std::tuple_cat(std::tie(outer_allocator()), _M_inner._M_tie()); }
+
+      template<typename _Alloc>
+	using __outermost_alloc_traits
+	  = allocator_traits<typename __outermost_type<_Alloc>::type>;
+
+#if ! __cpp_lib_make_obj_using_allocator
+      template<typename _Tp, typename... _Args>
+        void
+        _M_construct(__uses_alloc0, _Tp* __p, _Args&&... __args)
+        {
+	  typedef __outermost_alloc_traits<scoped_allocator_adaptor> _O_traits;
+	  _O_traits::construct(__outermost(*this), __p,
+			       std::forward<_Args>(__args)...);
+        }
+
+      typedef __uses_alloc1<typename __inner_type::__type> __uses_alloc1_;
+      typedef __uses_alloc2<typename __inner_type::__type> __uses_alloc2_;
+
+      template<typename _Tp, typename... _Args>
+        void
+        _M_construct(__uses_alloc1_, _Tp* __p, _Args&&... __args)
+        {
+	  typedef __outermost_alloc_traits<scoped_allocator_adaptor> _O_traits;
+	  _O_traits::construct(__outermost(*this), __p,
+			       allocator_arg, inner_allocator(),
+			       std::forward<_Args>(__args)...);
+        }
+
+      template<typename _Tp, typename... _Args>
+        void
+        _M_construct(__uses_alloc2_, _Tp* __p, _Args&&... __args)
+        {
+	  typedef __outermost_alloc_traits<scoped_allocator_adaptor> _O_traits;
+	  _O_traits::construct(__outermost(*this), __p,
+			       std::forward<_Args>(__args)...,
+			       inner_allocator());
+        }
+#endif // ! make_obj_using_allocator
+
+      template<typename _Alloc>
+        static _Alloc
+        _S_select_on_copy(const _Alloc& __a)
+        {
+          typedef allocator_traits<_Alloc> __a_traits;
+          return __a_traits::select_on_container_copy_construction(__a);
+        }
+
+      template<std::size_t... _Indices>
+        scoped_allocator_adaptor(tuple<const _OuterAlloc&,
+                                       const _InnerAllocs&...> __refs,
+                                 _Index_tuple<_Indices...>)
+        : _OuterAlloc(_S_select_on_copy(std::get<0>(__refs))),
+          _M_inner(_S_select_on_copy(std::get<_Indices+1>(__refs))...)
+        { }
+
+      // Used to constrain constructors to disallow invalid conversions.
+      template<typename _Alloc>
+        using _Constructible = typename enable_if<
+            is_constructible<_OuterAlloc, _Alloc>::value
+          >::type;
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 2975. Missing case for pair construction in scoped [...] allocators
+      template<typename _Tp>
+	struct __not_pair { using type = void; };
+
+      template<typename _Tp, typename _Up>
+	struct __not_pair<pair<_Tp, _Up>> { };
+
+    public:
+      typedef _OuterAlloc                       outer_allocator_type;
+      typedef typename __inner_type::__type     inner_allocator_type;
+
+      typedef typename __traits::value_type             value_type;
+      typedef typename __traits::size_type              size_type;
+      typedef typename __traits::difference_type        difference_type;
+      typedef typename __traits::pointer                pointer;
+      typedef typename __traits::const_pointer          const_pointer;
+      typedef typename __traits::void_pointer           void_pointer;
+      typedef typename __traits::const_void_pointer     const_void_pointer;
+
+      typedef typename __or_<
+	typename __traits::propagate_on_container_copy_assignment,
+	typename allocator_traits<_InnerAllocs>::
+	  propagate_on_container_copy_assignment...>::type
+	  propagate_on_container_copy_assignment;
+
+      typedef typename __or_<
+	typename __traits::propagate_on_container_move_assignment,
+	typename allocator_traits<_InnerAllocs>::
+	  propagate_on_container_move_assignment...>::type
+	  propagate_on_container_move_assignment;
+
+      typedef typename __or_<
+	typename __traits::propagate_on_container_swap,
+	typename allocator_traits<_InnerAllocs>::
+	  propagate_on_container_swap...>::type
+	  propagate_on_container_swap;
+
+      typedef typename __and_<
+	typename __traits::is_always_equal,
+	typename allocator_traits<_InnerAllocs>::is_always_equal...>::type
+	  is_always_equal;
+
+      template <class _Tp>
+        struct rebind
+        {
+          typedef scoped_allocator_adaptor<
+            typename __traits::template rebind_alloc<_Tp>,
+            _InnerAllocs...> other;
+        };
+
+      scoped_allocator_adaptor() : _OuterAlloc(), _M_inner() { }
+
+      template<typename _Outer2, typename = _Constructible<_Outer2>>
+        scoped_allocator_adaptor(_Outer2&& __outer,
+                                 const _InnerAllocs&... __inner)
+        : _OuterAlloc(std::forward<_Outer2>(__outer)),
+          _M_inner(__inner...)
+        { }
+
+      scoped_allocator_adaptor(const scoped_allocator_adaptor& __other)
+      : _OuterAlloc(__other.outer_allocator()),
+	_M_inner(__other._M_inner)
+      { }
+
+      scoped_allocator_adaptor(scoped_allocator_adaptor&& __other)
+      : _OuterAlloc(std::move(__other.outer_allocator())),
+	_M_inner(std::move(__other._M_inner))
+      { }
+
+      template<typename _Outer2, typename = _Constructible<const _Outer2&>>
+        scoped_allocator_adaptor(
+            const scoped_allocator_adaptor<_Outer2, _InnerAllocs...>& __other)
+        : _OuterAlloc(__other.outer_allocator()),
+          _M_inner(__other._M_inner)
+        { }
+
+      template<typename _Outer2, typename = _Constructible<_Outer2>>
+        scoped_allocator_adaptor(
+            scoped_allocator_adaptor<_Outer2, _InnerAllocs...>&& __other)
+        : _OuterAlloc(std::move(__other.outer_allocator())),
+          _M_inner(std::move(__other._M_inner))
+        { }
+
+      scoped_allocator_adaptor&
+      operator=(const scoped_allocator_adaptor&) = default;
+
+      scoped_allocator_adaptor&
+      operator=(scoped_allocator_adaptor&&) = default;
+
+      inner_allocator_type& inner_allocator() noexcept
+      { return _M_inner._M_get(this); }
+
+      const inner_allocator_type& inner_allocator() const noexcept
+      { return _M_inner._M_get(this); }
+
+      outer_allocator_type& outer_allocator() noexcept
+      { return static_cast<_OuterAlloc&>(*this); }
+
+      const outer_allocator_type& outer_allocator() const noexcept
+      { return static_cast<const _OuterAlloc&>(*this); }
+
+      _GLIBCXX_NODISCARD pointer allocate(size_type __n)
+      { return __traits::allocate(outer_allocator(), __n); }
+
+      _GLIBCXX_NODISCARD pointer allocate(size_type __n, const_void_pointer __hint)
+      { return __traits::allocate(outer_allocator(), __n, __hint); }
+
+      void deallocate(pointer __p, size_type __n)
+      { return __traits::deallocate(outer_allocator(), __p, __n); }
+
+      size_type max_size() const
+      { return __traits::max_size(outer_allocator()); }
+
+#if ! __cpp_lib_make_obj_using_allocator
+      template<typename _Tp, typename... _Args>
+	typename __not_pair<_Tp>::type
+	construct(_Tp* __p, _Args&&... __args)
+	{
+	  auto& __inner = inner_allocator();
+	  auto __use_tag
+	    = std::__use_alloc<_Tp, inner_allocator_type, _Args...>(__inner);
+	  _M_construct(__use_tag, __p, std::forward<_Args>(__args)...);
+	}
+
+      template<typename _T1, typename _T2, typename... _Args1,
+	       typename... _Args2>
+	void
+	construct(pair<_T1, _T2>* __p, piecewise_construct_t,
+		  tuple<_Args1...> __x, tuple<_Args2...> __y)
+	{
+	  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+	  // 2203.  wrong argument types for piecewise construction
+	  auto& __inner = inner_allocator();
+	  auto __x_use_tag
+	    = std::__use_alloc<_T1, inner_allocator_type, _Args1...>(__inner);
+	  auto __y_use_tag
+	    = std::__use_alloc<_T2, inner_allocator_type, _Args2...>(__inner);
+	  typename _Build_index_tuple<sizeof...(_Args1)>::__type __x_indices;
+	  typename _Build_index_tuple<sizeof...(_Args2)>::__type __y_indices;
+	  typedef __outermost_alloc_traits<scoped_allocator_adaptor> _O_traits;
+	  _O_traits::construct(__outermost(*this), __p, piecewise_construct,
+			       _M_construct_p(__x_use_tag, __x_indices, __x),
+			       _M_construct_p(__y_use_tag, __y_indices, __y));
+	}
+
+      template<typename _T1, typename _T2>
+	void
+	construct(pair<_T1, _T2>* __p)
+	{ construct(__p, piecewise_construct, tuple<>(), tuple<>()); }
+
+      template<typename _T1, typename _T2, typename _Up, typename _Vp>
+	void
+	construct(pair<_T1, _T2>* __p, _Up&& __u, _Vp&& __v)
+	{
+	  construct(__p, piecewise_construct,
+		    std::forward_as_tuple(std::forward<_Up>(__u)),
+		    std::forward_as_tuple(std::forward<_Vp>(__v)));
+	}
+
+      template<typename _T1, typename _T2, typename _Up, typename _Vp>
+	void
+	construct(pair<_T1, _T2>* __p, const pair<_Up, _Vp>& __x)
+	{
+	  construct(__p, piecewise_construct,
+		    std::forward_as_tuple(__x.first),
+		    std::forward_as_tuple(__x.second));
+	}
+
+      template<typename _T1, typename _T2, typename _Up, typename _Vp>
+	void
+	construct(pair<_T1, _T2>* __p, pair<_Up, _Vp>&& __x)
+	{
+	  construct(__p, piecewise_construct,
+		    std::forward_as_tuple(std::forward<_Up>(__x.first)),
+		    std::forward_as_tuple(std::forward<_Vp>(__x.second)));
+	}
+#else // make_obj_using_allocator
+      template<typename _Tp, typename... _Args>
+	__attribute__((__nonnull__))
+	void
+	construct(_Tp* __p, _Args&&... __args)
+	{
+	  typedef __outermost_alloc_traits<scoped_allocator_adaptor> _O_traits;
+	  std::apply([__p, this](auto&&... __newargs) {
+	      _O_traits::construct(__outermost(*this), __p,
+		  std::forward<decltype(__newargs)>(__newargs)...);
+	  },
+	  uses_allocator_construction_args<_Tp>(inner_allocator(),
+	    std::forward<_Args>(__args)...));
+	}
+#endif
+
+      template<typename _Tp>
+        void destroy(_Tp* __p)
+        {
+	  typedef __outermost_alloc_traits<scoped_allocator_adaptor> _O_traits;
+	  _O_traits::destroy(__outermost(*this), __p);
+	}
+
+      scoped_allocator_adaptor
+      select_on_container_copy_construction() const
+      {
+        typedef typename _Build_index_tuple<sizeof...(_InnerAllocs)>::__type
+	    _Indices;
+        return scoped_allocator_adaptor(_M_tie(), _Indices());
+      }
+
+      template <typename _OutA1, typename _OutA2, typename... _InA>
+      friend bool
+      operator==(const scoped_allocator_adaptor<_OutA1, _InA...>& __a,
+                 const scoped_allocator_adaptor<_OutA2, _InA...>& __b) noexcept;
+
+    private:
+#if ! __cpp_lib_make_obj_using_allocator
+      template<typename _Ind, typename... _Args>
+	tuple<_Args&&...>
+	_M_construct_p(__uses_alloc0, _Ind, tuple<_Args...>& __t)
+	{ return std::move(__t); }
+
+      template<size_t... _Ind, typename... _Args>
+	tuple<allocator_arg_t, inner_allocator_type&, _Args&&...>
+	_M_construct_p(__uses_alloc1_, _Index_tuple<_Ind...>,
+		       tuple<_Args...>& __t)
+	{
+	  return { allocator_arg, inner_allocator(),
+	      std::get<_Ind>(std::move(__t))...
+	  };
+	}
+
+      template<size_t... _Ind, typename... _Args>
+	tuple<_Args&&..., inner_allocator_type&>
+	_M_construct_p(__uses_alloc2_, _Index_tuple<_Ind...>,
+		       tuple<_Args...>& __t)
+	{
+	  return { std::get<_Ind>(std::move(__t))..., inner_allocator() };
+	}
+#endif // ! make_obj_using_allocator
+    };
+
+  /// @related std::scoped_allocator_adaptor
+  template <typename _OutA1, typename _OutA2, typename... _InA>
+    inline bool
+    operator==(const scoped_allocator_adaptor<_OutA1, _InA...>& __a,
+               const scoped_allocator_adaptor<_OutA2, _InA...>& __b) noexcept
+    {
+      return __a.outer_allocator() == __b.outer_allocator()
+          && __a._M_inner == __b._M_inner;
+    }
+
+#if __cpp_impl_three_way_comparison < 201907L
+  /// @related std::scoped_allocator_adaptor
+  template <typename _OutA1, typename _OutA2, typename... _InA>
+    inline bool
+    operator!=(const scoped_allocator_adaptor<_OutA1, _InA...>& __a,
+               const scoped_allocator_adaptor<_OutA2, _InA...>& __b) noexcept
+    { return !(__a == __b); }
+#endif
+
+  /// @}
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif // C++11
+
+#endif // _SCOPED_ALLOCATOR
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@set b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@set
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index 0000000000000000000000000000000000000000..45fed14c51e30e95878de793c165d79a69a40af8
--- /dev/null
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@@ -0,0 +1,111 @@
+// <set> -*- C++ -*-
+
+// Copyright (C) 2001-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/*
+ *
+ * Copyright (c) 1994
+ * Hewlett-Packard Company
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Hewlett-Packard Company makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ *
+ *
+ * Copyright (c) 1996,1997
+ * Silicon Graphics Computer Systems, Inc.
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Silicon Graphics makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ */
+
+/** @file include/set
+ *  This is a Standard C++ Library header.
+ */
+
+#ifndef _GLIBCXX_SET
+#define _GLIBCXX_SET 1
+
+#pragma GCC system_header
+
+#include <bits/stl_tree.h>
+#include <bits/stl_set.h>
+#include <bits/stl_multiset.h>
+#include <bits/range_access.h>
+#include <bits/erase_if.h>
+
+#ifdef _GLIBCXX_DEBUG
+# include <debug/set>
+#endif
+
+#if __cplusplus >= 201703L
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+  namespace pmr
+  {
+    template<typename _Tp> class polymorphic_allocator;
+    template<typename _Key, typename _Cmp = std::less<_Key>>
+      using set = std::set<_Key, _Cmp, polymorphic_allocator<_Key>>;
+    template<typename _Key, typename _Cmp = std::less<_Key>>
+      using multiset = std::multiset<_Key, _Cmp, polymorphic_allocator<_Key>>;
+  } // namespace pmr
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+#endif // C++17
+
+#if __cplusplus > 201703L
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+  template<typename _Key, typename _Compare, typename _Alloc,
+	   typename _Predicate>
+    inline typename set<_Key, _Compare, _Alloc>::size_type
+    erase_if(set<_Key, _Compare, _Alloc>& __cont, _Predicate __pred)
+    {
+      const _GLIBCXX_STD_C::set<_Key, _Compare, _Alloc>& __ucont = __cont;
+      return __detail::__erase_nodes_if(__cont, __ucont, __pred);
+    }
+
+  template<typename _Key, typename _Compare, typename _Alloc,
+	   typename _Predicate>
+    inline typename multiset<_Key, _Compare, _Alloc>::size_type
+    erase_if(multiset<_Key, _Compare, _Alloc>& __cont, _Predicate __pred)
+    {
+      const _GLIBCXX_STD_C::multiset<_Key, _Compare, _Alloc>& __ucont = __cont;
+      return __detail::__erase_nodes_if(__cont, __ucont, __pred);
+    }
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+#endif // C++20
+
+#endif /* _GLIBCXX_SET */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@set.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@set.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@shared_mutex b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@shared_mutex
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@@ -0,0 +1,860 @@
+// <shared_mutex> -*- C++ -*-
+
+// Copyright (C) 2013-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file include/shared_mutex
+ *  This is a Standard C++ Library header.
+ */
+
+#ifndef _GLIBCXX_SHARED_MUTEX
+#define _GLIBCXX_SHARED_MUTEX 1
+
+#pragma GCC system_header
+
+#if __cplusplus >= 201402L
+
+#include <bits/chrono.h>
+#include <bits/functexcept.h>
+#include <bits/move.h>        // move, __exchange
+#include <bits/std_mutex.h>   // defer_lock_t
+
+#if ! (_GLIBCXX_USE_PTHREAD_RWLOCK_T && _GTHREAD_USE_MUTEX_TIMEDLOCK)
+# include <condition_variable>
+#endif
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /**
+   * @addtogroup mutexes
+   * @{
+   */
+
+#ifdef _GLIBCXX_HAS_GTHREADS
+
+#if __cplusplus >= 201703L
+#define __cpp_lib_shared_mutex 201505L
+  class shared_mutex;
+#endif
+
+#define __cpp_lib_shared_timed_mutex 201402L
+  class shared_timed_mutex;
+
+  /// @cond undocumented
+
+#if _GLIBCXX_USE_PTHREAD_RWLOCK_T
+#ifdef __gthrw
+#define _GLIBCXX_GTHRW(name) \
+  __gthrw(pthread_ ## name); \
+  static inline int \
+  __glibcxx_ ## name (pthread_rwlock_t *__rwlock) \
+  { \
+    if (__gthread_active_p ()) \
+      return __gthrw_(pthread_ ## name) (__rwlock); \
+    else \
+      return 0; \
+  }
+  _GLIBCXX_GTHRW(rwlock_rdlock)
+  _GLIBCXX_GTHRW(rwlock_tryrdlock)
+  _GLIBCXX_GTHRW(rwlock_wrlock)
+  _GLIBCXX_GTHRW(rwlock_trywrlock)
+  _GLIBCXX_GTHRW(rwlock_unlock)
+# ifndef PTHREAD_RWLOCK_INITIALIZER
+  _GLIBCXX_GTHRW(rwlock_destroy)
+  __gthrw(pthread_rwlock_init);
+  static inline int
+  __glibcxx_rwlock_init (pthread_rwlock_t *__rwlock)
+  {
+    if (__gthread_active_p ())
+      return __gthrw_(pthread_rwlock_init) (__rwlock, NULL);
+    else
+      return 0;
+  }
+# endif
+# if _GTHREAD_USE_MUTEX_TIMEDLOCK
+   __gthrw(pthread_rwlock_timedrdlock);
+  static inline int
+  __glibcxx_rwlock_timedrdlock (pthread_rwlock_t *__rwlock,
+				const timespec *__ts)
+  {
+    if (__gthread_active_p ())
+      return __gthrw_(pthread_rwlock_timedrdlock) (__rwlock, __ts);
+    else
+      return 0;
+  }
+   __gthrw(pthread_rwlock_timedwrlock);
+  static inline int
+  __glibcxx_rwlock_timedwrlock (pthread_rwlock_t *__rwlock,
+				const timespec *__ts)
+  {
+    if (__gthread_active_p ())
+      return __gthrw_(pthread_rwlock_timedwrlock) (__rwlock, __ts);
+    else
+      return 0;
+  }
+# endif
+#else
+  static inline int
+  __glibcxx_rwlock_rdlock (pthread_rwlock_t *__rwlock)
+  { return pthread_rwlock_rdlock (__rwlock); }
+  static inline int
+  __glibcxx_rwlock_tryrdlock (pthread_rwlock_t *__rwlock)
+  { return pthread_rwlock_tryrdlock (__rwlock); }
+  static inline int
+  __glibcxx_rwlock_wrlock (pthread_rwlock_t *__rwlock)
+  { return pthread_rwlock_wrlock (__rwlock); }
+  static inline int
+  __glibcxx_rwlock_trywrlock (pthread_rwlock_t *__rwlock)
+  { return pthread_rwlock_trywrlock (__rwlock); }
+  static inline int
+  __glibcxx_rwlock_unlock (pthread_rwlock_t *__rwlock)
+  { return pthread_rwlock_unlock (__rwlock); }
+  static inline int
+  __glibcxx_rwlock_destroy(pthread_rwlock_t *__rwlock)
+  { return pthread_rwlock_destroy (__rwlock); }
+  static inline int
+  __glibcxx_rwlock_init(pthread_rwlock_t *__rwlock)
+  { return pthread_rwlock_init (__rwlock, NULL); }
+# if _GTHREAD_USE_MUTEX_TIMEDLOCK
+  static inline int
+  __glibcxx_rwlock_timedrdlock (pthread_rwlock_t *__rwlock,
+				const timespec *__ts)
+  { return pthread_rwlock_timedrdlock (__rwlock, __ts); }
+  static inline int
+  __glibcxx_rwlock_timedwrlock (pthread_rwlock_t *__rwlock,
+				const timespec *__ts)
+  { return pthread_rwlock_timedwrlock (__rwlock, __ts); }
+# endif
+#endif
+
+  /// A shared mutex type implemented using pthread_rwlock_t.
+  class __shared_mutex_pthread
+  {
+    friend class shared_timed_mutex;
+
+#ifdef PTHREAD_RWLOCK_INITIALIZER
+    pthread_rwlock_t	_M_rwlock = PTHREAD_RWLOCK_INITIALIZER;
+
+  public:
+    __shared_mutex_pthread() = default;
+    ~__shared_mutex_pthread() = default;
+#else
+    pthread_rwlock_t	_M_rwlock;
+
+  public:
+    __shared_mutex_pthread()
+    {
+      int __ret = __glibcxx_rwlock_init(&_M_rwlock);
+      if (__ret == ENOMEM)
+	__throw_bad_alloc();
+      else if (__ret == EAGAIN)
+	__throw_system_error(int(errc::resource_unavailable_try_again));
+      else if (__ret == EPERM)
+	__throw_system_error(int(errc::operation_not_permitted));
+      // Errors not handled: EBUSY, EINVAL
+      __glibcxx_assert(__ret == 0);
+    }
+
+    ~__shared_mutex_pthread()
+    {
+      int __ret __attribute((__unused__)) = __glibcxx_rwlock_destroy(&_M_rwlock);
+      // Errors not handled: EBUSY, EINVAL
+      __glibcxx_assert(__ret == 0);
+    }
+#endif
+
+    __shared_mutex_pthread(const __shared_mutex_pthread&) = delete;
+    __shared_mutex_pthread& operator=(const __shared_mutex_pthread&) = delete;
+
+    void
+    lock()
+    {
+      int __ret = __glibcxx_rwlock_wrlock(&_M_rwlock);
+      if (__ret == EDEADLK)
+	__throw_system_error(int(errc::resource_deadlock_would_occur));
+      // Errors not handled: EINVAL
+      __glibcxx_assert(__ret == 0);
+    }
+
+    bool
+    try_lock()
+    {
+      int __ret = __glibcxx_rwlock_trywrlock(&_M_rwlock);
+      if (__ret == EBUSY) return false;
+      // Errors not handled: EINVAL
+      __glibcxx_assert(__ret == 0);
+      return true;
+    }
+
+    void
+    unlock()
+    {
+      int __ret __attribute((__unused__)) = __glibcxx_rwlock_unlock(&_M_rwlock);
+      // Errors not handled: EPERM, EBUSY, EINVAL
+      __glibcxx_assert(__ret == 0);
+    }
+
+    // Shared ownership
+
+    void
+    lock_shared()
+    {
+      int __ret;
+      // We retry if we exceeded the maximum number of read locks supported by
+      // the POSIX implementation; this can result in busy-waiting, but this
+      // is okay based on the current specification of forward progress
+      // guarantees by the standard.
+      do
+	__ret = __glibcxx_rwlock_rdlock(&_M_rwlock);
+      while (__ret == EAGAIN);
+      if (__ret == EDEADLK)
+	__throw_system_error(int(errc::resource_deadlock_would_occur));
+      // Errors not handled: EINVAL
+      __glibcxx_assert(__ret == 0);
+    }
+
+    bool
+    try_lock_shared()
+    {
+      int __ret = __glibcxx_rwlock_tryrdlock(&_M_rwlock);
+      // If the maximum number of read locks has been exceeded, we just fail
+      // to acquire the lock.  Unlike for lock(), we are not allowed to throw
+      // an exception.
+      if (__ret == EBUSY || __ret == EAGAIN) return false;
+      // Errors not handled: EINVAL
+      __glibcxx_assert(__ret == 0);
+      return true;
+    }
+
+    void
+    unlock_shared()
+    {
+      unlock();
+    }
+
+    void* native_handle() { return &_M_rwlock; }
+  };
+#endif
+
+#if ! (_GLIBCXX_USE_PTHREAD_RWLOCK_T && _GTHREAD_USE_MUTEX_TIMEDLOCK)
+  /// A shared mutex type implemented using std::condition_variable.
+  class __shared_mutex_cv
+  {
+    friend class shared_timed_mutex;
+
+    // Based on Howard Hinnant's reference implementation from N2406.
+
+    // The high bit of _M_state is the write-entered flag which is set to
+    // indicate a writer has taken the lock or is queuing to take the lock.
+    // The remaining bits are the count of reader locks.
+    //
+    // To take a reader lock, block on gate1 while the write-entered flag is
+    // set or the maximum number of reader locks is held, then increment the
+    // reader lock count.
+    // To release, decrement the count, then if the write-entered flag is set
+    // and the count is zero then signal gate2 to wake a queued writer,
+    // otherwise if the maximum number of reader locks was held signal gate1
+    // to wake a reader.
+    //
+    // To take a writer lock, block on gate1 while the write-entered flag is
+    // set, then set the write-entered flag to start queueing, then block on
+    // gate2 while the number of reader locks is non-zero.
+    // To release, unset the write-entered flag and signal gate1 to wake all
+    // blocked readers and writers.
+    //
+    // This means that when no reader locks are held readers and writers get
+    // equal priority. When one or more reader locks is held a writer gets
+    // priority and no more reader locks can be taken while the writer is
+    // queued.
+
+    // Only locked when accessing _M_state or waiting on condition variables.
+    mutex		_M_mut;
+    // Used to block while write-entered is set or reader count at maximum.
+    condition_variable	_M_gate1;
+    // Used to block queued writers while reader count is non-zero.
+    condition_variable	_M_gate2;
+    // The write-entered flag and reader count.
+    unsigned		_M_state;
+
+    static constexpr unsigned _S_write_entered
+      = 1U << (sizeof(unsigned)*__CHAR_BIT__ - 1);
+    static constexpr unsigned _S_max_readers = ~_S_write_entered;
+
+    // Test whether the write-entered flag is set. _M_mut must be locked.
+    bool _M_write_entered() const { return _M_state & _S_write_entered; }
+
+    // The number of reader locks currently held. _M_mut must be locked.
+    unsigned _M_readers() const { return _M_state & _S_max_readers; }
+
+  public:
+    __shared_mutex_cv() : _M_state(0) {}
+
+    ~__shared_mutex_cv()
+    {
+      __glibcxx_assert( _M_state == 0 );
+    }
+
+    __shared_mutex_cv(const __shared_mutex_cv&) = delete;
+    __shared_mutex_cv& operator=(const __shared_mutex_cv&) = delete;
+
+    // Exclusive ownership
+
+    void
+    lock()
+    {
+      unique_lock<mutex> __lk(_M_mut);
+      // Wait until we can set the write-entered flag.
+      _M_gate1.wait(__lk, [=]{ return !_M_write_entered(); });
+      _M_state |= _S_write_entered;
+      // Then wait until there are no more readers.
+      _M_gate2.wait(__lk, [=]{ return _M_readers() == 0; });
+    }
+
+    bool
+    try_lock()
+    {
+      unique_lock<mutex> __lk(_M_mut, try_to_lock);
+      if (__lk.owns_lock() && _M_state == 0)
+	{
+	  _M_state = _S_write_entered;
+	  return true;
+	}
+      return false;
+    }
+
+    void
+    unlock()
+    {
+      lock_guard<mutex> __lk(_M_mut);
+      __glibcxx_assert( _M_write_entered() );
+      _M_state = 0;
+      // call notify_all() while mutex is held so that another thread can't
+      // lock and unlock the mutex then destroy *this before we make the call.
+      _M_gate1.notify_all();
+    }
+
+    // Shared ownership
+
+    void
+    lock_shared()
+    {
+      unique_lock<mutex> __lk(_M_mut);
+      _M_gate1.wait(__lk, [=]{ return _M_state < _S_max_readers; });
+      ++_M_state;
+    }
+
+    bool
+    try_lock_shared()
+    {
+      unique_lock<mutex> __lk(_M_mut, try_to_lock);
+      if (!__lk.owns_lock())
+	return false;
+      if (_M_state < _S_max_readers)
+	{
+	  ++_M_state;
+	  return true;
+	}
+      return false;
+    }
+
+    void
+    unlock_shared()
+    {
+      lock_guard<mutex> __lk(_M_mut);
+      __glibcxx_assert( _M_readers() > 0 );
+      auto __prev = _M_state--;
+      if (_M_write_entered())
+	{
+	  // Wake the queued writer if there are no more readers.
+	  if (_M_readers() == 0)
+	    _M_gate2.notify_one();
+	  // No need to notify gate1 because we give priority to the queued
+	  // writer, and that writer will eventually notify gate1 after it
+	  // clears the write-entered flag.
+	}
+      else
+	{
+	  // Wake any thread that was blocked on reader overflow.
+	  if (__prev == _S_max_readers)
+	    _M_gate1.notify_one();
+	}
+    }
+  };
+#endif
+  /// @endcond
+
+#if __cplusplus >= 201703L
+  /// The standard shared mutex type.
+  class shared_mutex
+  {
+  public:
+    shared_mutex() = default;
+    ~shared_mutex() = default;
+
+    shared_mutex(const shared_mutex&) = delete;
+    shared_mutex& operator=(const shared_mutex&) = delete;
+
+    // Exclusive ownership
+
+    void lock() { _M_impl.lock(); }
+    bool try_lock() { return _M_impl.try_lock(); }
+    void unlock() { _M_impl.unlock(); }
+
+    // Shared ownership
+
+    void lock_shared() { _M_impl.lock_shared(); }
+    bool try_lock_shared() { return _M_impl.try_lock_shared(); }
+    void unlock_shared() { _M_impl.unlock_shared(); }
+
+#if _GLIBCXX_USE_PTHREAD_RWLOCK_T
+    typedef void* native_handle_type;
+    native_handle_type native_handle() { return _M_impl.native_handle(); }
+
+  private:
+    __shared_mutex_pthread _M_impl;
+#else
+  private:
+    __shared_mutex_cv _M_impl;
+#endif
+  };
+#endif // C++17
+
+  /// @cond undocumented
+#if _GLIBCXX_USE_PTHREAD_RWLOCK_T && _GTHREAD_USE_MUTEX_TIMEDLOCK
+  using __shared_timed_mutex_base = __shared_mutex_pthread;
+#else
+  using __shared_timed_mutex_base = __shared_mutex_cv;
+#endif
+  /// @endcond
+
+  /// The standard shared timed mutex type.
+  class shared_timed_mutex
+  : private __shared_timed_mutex_base
+  {
+    using _Base = __shared_timed_mutex_base;
+
+    // Must use the same clock as condition_variable for __shared_mutex_cv.
+#ifdef _GLIBCXX_USE_PTHREAD_RWLOCK_CLOCKLOCK
+    using __clock_t = chrono::steady_clock;
+#else
+    using __clock_t = chrono::system_clock;
+#endif
+
+  public:
+    shared_timed_mutex() = default;
+    ~shared_timed_mutex() = default;
+
+    shared_timed_mutex(const shared_timed_mutex&) = delete;
+    shared_timed_mutex& operator=(const shared_timed_mutex&) = delete;
+
+    // Exclusive ownership
+
+    void lock() { _Base::lock(); }
+    bool try_lock() { return _Base::try_lock(); }
+    void unlock() { _Base::unlock(); }
+
+    template<typename _Rep, typename _Period>
+      bool
+      try_lock_for(const chrono::duration<_Rep, _Period>& __rtime)
+      {
+	auto __rt = chrono::duration_cast<__clock_t::duration>(__rtime);
+	if (ratio_greater<__clock_t::period, _Period>())
+	  ++__rt;
+	return try_lock_until(__clock_t::now() + __rt);
+      }
+
+    // Shared ownership
+
+    void lock_shared() { _Base::lock_shared(); }
+    bool try_lock_shared() { return _Base::try_lock_shared(); }
+    void unlock_shared() { _Base::unlock_shared(); }
+
+    template<typename _Rep, typename _Period>
+      bool
+      try_lock_shared_for(const chrono::duration<_Rep, _Period>& __rtime)
+      {
+	auto __rt = chrono::duration_cast<__clock_t::duration>(__rtime);
+	if (ratio_greater<__clock_t::period, _Period>())
+	  ++__rt;
+	return try_lock_shared_until(__clock_t::now() + __rt);
+      }
+
+#if _GLIBCXX_USE_PTHREAD_RWLOCK_T && _GTHREAD_USE_MUTEX_TIMEDLOCK
+
+    // Exclusive ownership
+
+    template<typename _Duration>
+      bool
+      try_lock_until(const chrono::time_point<chrono::system_clock,
+		     _Duration>& __atime)
+      {
+	auto __s = chrono::time_point_cast<chrono::seconds>(__atime);
+	auto __ns = chrono::duration_cast<chrono::nanoseconds>(__atime - __s);
+
+	__gthread_time_t __ts =
+	  {
+	    static_cast<std::time_t>(__s.time_since_epoch().count()),
+	    static_cast<long>(__ns.count())
+	  };
+
+	int __ret = __glibcxx_rwlock_timedwrlock(&_M_rwlock, &__ts);
+	// On self-deadlock, we just fail to acquire the lock.  Technically,
+	// the program violated the precondition.
+	if (__ret == ETIMEDOUT || __ret == EDEADLK)
+	  return false;
+	// Errors not handled: EINVAL
+	__glibcxx_assert(__ret == 0);
+	return true;
+      }
+
+#ifdef _GLIBCXX_USE_PTHREAD_RWLOCK_CLOCKLOCK
+    template<typename _Duration>
+      bool
+      try_lock_until(const chrono::time_point<chrono::steady_clock,
+		   _Duration>& __atime)
+      {
+	auto __s = chrono::time_point_cast<chrono::seconds>(__atime);
+	auto __ns = chrono::duration_cast<chrono::nanoseconds>(__atime - __s);
+
+	__gthread_time_t __ts =
+	  {
+	    static_cast<std::time_t>(__s.time_since_epoch().count()),
+	    static_cast<long>(__ns.count())
+	  };
+
+	int __ret = pthread_rwlock_clockwrlock(&_M_rwlock, CLOCK_MONOTONIC,
+					       &__ts);
+	// On self-deadlock, we just fail to acquire the lock.  Technically,
+	// the program violated the precondition.
+	if (__ret == ETIMEDOUT || __ret == EDEADLK)
+	  return false;
+	// Errors not handled: EINVAL
+	__glibcxx_assert(__ret == 0);
+	return true;
+      }
+#endif
+
+    template<typename _Clock, typename _Duration>
+      bool
+      try_lock_until(const chrono::time_point<_Clock, _Duration>& __atime)
+      {
+#if __cplusplus > 201703L
+	static_assert(chrono::is_clock_v<_Clock>);
+#endif
+	// The user-supplied clock may not tick at the same rate as
+	// steady_clock, so we must loop in order to guarantee that
+	// the timeout has expired before returning false.
+	typename _Clock::time_point __now = _Clock::now();
+	do {
+	    auto __rtime = __atime - __now;
+	    if (try_lock_for(__rtime))
+	      return true;
+	    __now = _Clock::now();
+	} while (__atime > __now);
+	return false;
+      }
+
+    // Shared ownership
+
+    template<typename _Duration>
+      bool
+      try_lock_shared_until(const chrono::time_point<chrono::system_clock,
+			    _Duration>& __atime)
+      {
+	auto __s = chrono::time_point_cast<chrono::seconds>(__atime);
+	auto __ns = chrono::duration_cast<chrono::nanoseconds>(__atime - __s);
+
+	__gthread_time_t __ts =
+	  {
+	    static_cast<std::time_t>(__s.time_since_epoch().count()),
+	    static_cast<long>(__ns.count())
+	  };
+
+	int __ret;
+	// Unlike for lock(), we are not allowed to throw an exception so if
+	// the maximum number of read locks has been exceeded, or we would
+	// deadlock, we just try to acquire the lock again (and will time out
+	// eventually).
+	// In cases where we would exceed the maximum number of read locks
+	// throughout the whole time until the timeout, we will fail to
+	// acquire the lock even if it would be logically free; however, this
+	// is allowed by the standard, and we made a "strong effort"
+	// (see C++14 30.4.1.4p26).
+	// For cases where the implementation detects a deadlock we
+	// intentionally block and timeout so that an early return isn't
+	// mistaken for a spurious failure, which might help users realise
+	// there is a deadlock.
+	do
+	  __ret = __glibcxx_rwlock_timedrdlock(&_M_rwlock, &__ts);
+	while (__ret == EAGAIN || __ret == EDEADLK);
+	if (__ret == ETIMEDOUT)
+	  return false;
+	// Errors not handled: EINVAL
+	__glibcxx_assert(__ret == 0);
+	return true;
+      }
+
+#ifdef _GLIBCXX_USE_PTHREAD_RWLOCK_CLOCKLOCK
+    template<typename _Duration>
+      bool
+      try_lock_shared_until(const chrono::time_point<chrono::steady_clock,
+			    _Duration>& __atime)
+      {
+	auto __s = chrono::time_point_cast<chrono::seconds>(__atime);
+	auto __ns = chrono::duration_cast<chrono::nanoseconds>(__atime - __s);
+
+	__gthread_time_t __ts =
+	  {
+	    static_cast<std::time_t>(__s.time_since_epoch().count()),
+	    static_cast<long>(__ns.count())
+	  };
+
+	int __ret = pthread_rwlock_clockrdlock(&_M_rwlock, CLOCK_MONOTONIC,
+					       &__ts);
+	// On self-deadlock, we just fail to acquire the lock.  Technically,
+	// the program violated the precondition.
+	if (__ret == ETIMEDOUT || __ret == EDEADLK)
+	  return false;
+	// Errors not handled: EINVAL
+	__glibcxx_assert(__ret == 0);
+	return true;
+      }
+#endif
+
+    template<typename _Clock, typename _Duration>
+      bool
+      try_lock_shared_until(const chrono::time_point<_Clock,
+						     _Duration>& __atime)
+      {
+#if __cplusplus > 201703L
+	static_assert(chrono::is_clock_v<_Clock>);
+#endif
+	// The user-supplied clock may not tick at the same rate as
+	// steady_clock, so we must loop in order to guarantee that
+	// the timeout has expired before returning false.
+	typename _Clock::time_point __now = _Clock::now();
+	do {
+	    auto __rtime = __atime - __now;
+	    if (try_lock_shared_for(__rtime))
+	      return true;
+	    __now = _Clock::now();
+	} while (__atime > __now);
+	return false;
+      }
+
+#else // ! (_GLIBCXX_USE_PTHREAD_RWLOCK_T && _GTHREAD_USE_MUTEX_TIMEDLOCK)
+
+    // Exclusive ownership
+
+    template<typename _Clock, typename _Duration>
+      bool
+      try_lock_until(const chrono::time_point<_Clock, _Duration>& __abs_time)
+      {
+	unique_lock<mutex> __lk(_M_mut);
+	if (!_M_gate1.wait_until(__lk, __abs_time,
+				 [=]{ return !_M_write_entered(); }))
+	  {
+	    return false;
+	  }
+	_M_state |= _S_write_entered;
+	if (!_M_gate2.wait_until(__lk, __abs_time,
+				 [=]{ return _M_readers() == 0; }))
+	  {
+	    _M_state ^= _S_write_entered;
+	    // Wake all threads blocked while the write-entered flag was set.
+	    _M_gate1.notify_all();
+	    return false;
+	  }
+	return true;
+      }
+
+    // Shared ownership
+
+    template <typename _Clock, typename _Duration>
+      bool
+      try_lock_shared_until(const chrono::time_point<_Clock,
+						     _Duration>& __abs_time)
+      {
+	unique_lock<mutex> __lk(_M_mut);
+	if (!_M_gate1.wait_until(__lk, __abs_time,
+				 [=]{ return _M_state < _S_max_readers; }))
+	  {
+	    return false;
+	  }
+	++_M_state;
+	return true;
+      }
+
+#endif // _GLIBCXX_USE_PTHREAD_RWLOCK_T && _GTHREAD_USE_MUTEX_TIMEDLOCK
+  };
+#endif // _GLIBCXX_HAS_GTHREADS
+
+  /// shared_lock
+  template<typename _Mutex>
+    class shared_lock
+    {
+    public:
+      typedef _Mutex mutex_type;
+
+      // Shared locking
+
+      shared_lock() noexcept : _M_pm(nullptr), _M_owns(false) { }
+
+      explicit
+      shared_lock(mutex_type& __m)
+      : _M_pm(std::__addressof(__m)), _M_owns(true)
+      { __m.lock_shared(); }
+
+      shared_lock(mutex_type& __m, defer_lock_t) noexcept
+      : _M_pm(std::__addressof(__m)), _M_owns(false) { }
+
+      shared_lock(mutex_type& __m, try_to_lock_t)
+      : _M_pm(std::__addressof(__m)), _M_owns(__m.try_lock_shared()) { }
+
+      shared_lock(mutex_type& __m, adopt_lock_t)
+      : _M_pm(std::__addressof(__m)), _M_owns(true) { }
+
+      template<typename _Clock, typename _Duration>
+	shared_lock(mutex_type& __m,
+		    const chrono::time_point<_Clock, _Duration>& __abs_time)
+      : _M_pm(std::__addressof(__m)),
+	_M_owns(__m.try_lock_shared_until(__abs_time)) { }
+
+      template<typename _Rep, typename _Period>
+	shared_lock(mutex_type& __m,
+		    const chrono::duration<_Rep, _Period>& __rel_time)
+      : _M_pm(std::__addressof(__m)),
+	_M_owns(__m.try_lock_shared_for(__rel_time)) { }
+
+      ~shared_lock()
+      {
+	if (_M_owns)
+	  _M_pm->unlock_shared();
+      }
+
+      shared_lock(shared_lock const&) = delete;
+      shared_lock& operator=(shared_lock const&) = delete;
+
+      shared_lock(shared_lock&& __sl) noexcept : shared_lock()
+      { swap(__sl); }
+
+      shared_lock&
+      operator=(shared_lock&& __sl) noexcept
+      {
+	shared_lock(std::move(__sl)).swap(*this);
+	return *this;
+      }
+
+      void
+      lock()
+      {
+	_M_lockable();
+	_M_pm->lock_shared();
+	_M_owns = true;
+      }
+
+      bool
+      try_lock()
+      {
+	_M_lockable();
+	return _M_owns = _M_pm->try_lock_shared();
+      }
+
+      template<typename _Rep, typename _Period>
+	bool
+	try_lock_for(const chrono::duration<_Rep, _Period>& __rel_time)
+	{
+	  _M_lockable();
+	  return _M_owns = _M_pm->try_lock_shared_for(__rel_time);
+	}
+
+      template<typename _Clock, typename _Duration>
+	bool
+	try_lock_until(const chrono::time_point<_Clock, _Duration>& __abs_time)
+	{
+	  _M_lockable();
+	  return _M_owns = _M_pm->try_lock_shared_until(__abs_time);
+	}
+
+      void
+      unlock()
+      {
+	if (!_M_owns)
+	  __throw_system_error(int(errc::resource_deadlock_would_occur));
+	_M_pm->unlock_shared();
+	_M_owns = false;
+      }
+
+      // Setters
+
+      void
+      swap(shared_lock& __u) noexcept
+      {
+	std::swap(_M_pm, __u._M_pm);
+	std::swap(_M_owns, __u._M_owns);
+      }
+
+      mutex_type*
+      release() noexcept
+      {
+	_M_owns = false;
+	return std::__exchange(_M_pm, nullptr);
+      }
+
+      // Getters
+
+      bool owns_lock() const noexcept { return _M_owns; }
+
+      explicit operator bool() const noexcept { return _M_owns; }
+
+      mutex_type* mutex() const noexcept { return _M_pm; }
+
+    private:
+      void
+      _M_lockable() const
+      {
+	if (_M_pm == nullptr)
+	  __throw_system_error(int(errc::operation_not_permitted));
+	if (_M_owns)
+	  __throw_system_error(int(errc::resource_deadlock_would_occur));
+      }
+
+      mutex_type*	_M_pm;
+      bool		_M_owns;
+    };
+
+  /// Swap specialization for shared_lock
+  /// @relates shared_mutex
+  template<typename _Mutex>
+    void
+    swap(shared_lock<_Mutex>& __x, shared_lock<_Mutex>& __y) noexcept
+    { __x.swap(__y); }
+
+  /// @} group mutexes
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif // C++14
+
+#endif // _GLIBCXX_SHARED_MUTEX
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+// String based streams -*- C++ -*-
+
+// Copyright (C) 1997-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file include/sstream
+ *  This is a Standard C++ Library header.
+ */
+
+//
+// ISO C++ 14882: 27.7  String-based streams
+//
+
+#ifndef _GLIBCXX_SSTREAM
+#define _GLIBCXX_SSTREAM 1
+
+#pragma GCC system_header
+
+#include <istream>
+#include <ostream>
+#include <bits/alloc_traits.h> // allocator_traits, __allocator_like
+
+#if __cplusplus > 201703L && _GLIBCXX_USE_CXX11_ABI
+# define _GLIBCXX_LVAL_REF_QUAL &
+#else
+# define _GLIBCXX_LVAL_REF_QUAL
+#endif
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+_GLIBCXX_BEGIN_NAMESPACE_CXX11
+
+  // [27.7.1] template class basic_stringbuf
+  /**
+   *  @brief  The actual work of input and output (for std::string).
+   *  @ingroup io
+   *
+   *  @tparam _CharT  Type of character stream.
+   *  @tparam _Traits  Traits for character type, defaults to
+   *                   char_traits<_CharT>.
+   *  @tparam _Alloc  Allocator type, defaults to allocator<_CharT>.
+   *
+   *  This class associates either or both of its input and output sequences
+   *  with a sequence of characters, which can be initialized from, or made
+   *  available as, a @c std::basic_string.  (Paraphrased from [27.7.1]/1.)
+   *
+   *  For this class, open modes (of type @c ios_base::openmode) have
+   *  @c in set if the input sequence can be read, and @c out set if the
+   *  output sequence can be written.
+  */
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    class basic_stringbuf : public basic_streambuf<_CharT, _Traits>
+    {
+      struct __xfer_bufptrs;
+
+#if __cplusplus >= 201103L
+      using allocator_traits = std::allocator_traits<_Alloc>;
+      using _Noexcept_swap
+	= __or_<typename allocator_traits::propagate_on_container_swap,
+		typename allocator_traits::is_always_equal>;
+#endif
+
+    public:
+      // Types:
+      typedef _CharT 					char_type;
+      typedef _Traits 					traits_type;
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 251. basic_stringbuf missing allocator_type
+      typedef _Alloc				       	allocator_type;
+      typedef typename traits_type::int_type 		int_type;
+      typedef typename traits_type::pos_type 		pos_type;
+      typedef typename traits_type::off_type 		off_type;
+
+      typedef basic_streambuf<char_type, traits_type>  	__streambuf_type;
+      typedef basic_string<char_type, _Traits, _Alloc> 	__string_type;
+      typedef typename __string_type::size_type		__size_type;
+
+    protected:
+      /// Place to stash in || out || in | out settings for current stringbuf.
+      ios_base::openmode 	_M_mode;
+
+      // Data Members:
+      __string_type 		_M_string;
+
+    public:
+      // Constructors:
+
+      /**
+       *  @brief  Starts with an empty string buffer.
+       *
+       *  The default constructor initializes the parent class using its
+       *  own default ctor.
+      */
+      basic_stringbuf()
+      : __streambuf_type(), _M_mode(ios_base::in | ios_base::out), _M_string()
+      { }
+
+      /**
+       *  @brief  Starts with an empty string buffer.
+       *  @param  __mode  Whether the buffer can read, or write, or both.
+       *
+       *  The default constructor initializes the parent class using its
+       *  own default ctor.
+      */
+      explicit
+      basic_stringbuf(ios_base::openmode __mode)
+      : __streambuf_type(), _M_mode(__mode), _M_string()
+      { }
+
+      /**
+       *  @brief  Starts with an existing string buffer.
+       *  @param  __str  A string to copy as a starting buffer.
+       *  @param  __mode  Whether the buffer can read, or write, or both.
+       *
+       *  This constructor initializes the parent class using its
+       *  own default ctor.
+      */
+      explicit
+      basic_stringbuf(const __string_type& __str,
+		      ios_base::openmode __mode = ios_base::in | ios_base::out)
+      : __streambuf_type(), _M_mode(),
+	_M_string(__str.data(), __str.size(), __str.get_allocator())
+      { _M_stringbuf_init(__mode); }
+
+#if __cplusplus >= 201103L
+      basic_stringbuf(const basic_stringbuf&) = delete;
+
+      basic_stringbuf(basic_stringbuf&& __rhs)
+      : basic_stringbuf(std::move(__rhs), __xfer_bufptrs(__rhs, this))
+      { __rhs._M_sync(const_cast<char_type*>(__rhs._M_string.data()), 0, 0); }
+
+#if __cplusplus > 201703L && _GLIBCXX_USE_CXX11_ABI
+      explicit
+      basic_stringbuf(const allocator_type& __a)
+      : basic_stringbuf(ios_base::in | std::ios_base::out, __a)
+      { }
+
+      basic_stringbuf(ios_base::openmode __mode,
+		      const allocator_type& __a)
+      : __streambuf_type(), _M_mode(__mode), _M_string(__a)
+      { }
+
+      explicit
+      basic_stringbuf(__string_type&& __s,
+		      ios_base::openmode __mode = ios_base::in
+						  | ios_base::out)
+      : __streambuf_type(), _M_mode(__mode), _M_string(std::move(__s))
+      { _M_stringbuf_init(__mode); }
+
+      template<typename _SAlloc>
+	basic_stringbuf(const basic_string<_CharT, _Traits, _SAlloc>& __s,
+			const allocator_type& __a)
+	: basic_stringbuf(__s, ios_base::in | std::ios_base::out, __a)
+	{ }
+
+      template<typename _SAlloc>
+	basic_stringbuf(const basic_string<_CharT, _Traits, _SAlloc>& __s,
+			ios_base::openmode __mode,
+			const allocator_type& __a)
+	: __streambuf_type(), _M_mode(__mode),
+	  _M_string(__s.data(), __s.size(), __a)
+	{ _M_stringbuf_init(__mode); }
+
+      template<typename _SAlloc>
+	explicit
+	basic_stringbuf(const basic_string<_CharT, _Traits, _SAlloc>& __s,
+			ios_base::openmode __mode = ios_base::in
+						    | ios_base::out)
+	: basic_stringbuf(__s, __mode, allocator_type{})
+	{ }
+
+      basic_stringbuf(basic_stringbuf&& __rhs, const allocator_type& __a)
+      : basic_stringbuf(std::move(__rhs), __a, __xfer_bufptrs(__rhs, this))
+      { __rhs._M_sync(const_cast<char_type*>(__rhs._M_string.data()), 0, 0); }
+
+      allocator_type get_allocator() const noexcept
+      { return _M_string.get_allocator(); }
+#endif // C++20
+
+      // 27.8.2.2 Assign and swap:
+
+      basic_stringbuf&
+      operator=(const basic_stringbuf&) = delete;
+
+      basic_stringbuf&
+      operator=(basic_stringbuf&& __rhs)
+      {
+	__xfer_bufptrs __st{__rhs, this};
+	const __streambuf_type& __base = __rhs;
+	__streambuf_type::operator=(__base);
+	this->pubimbue(__rhs.getloc());
+	_M_mode = __rhs._M_mode;
+	_M_string = std::move(__rhs._M_string);
+	__rhs._M_sync(const_cast<char_type*>(__rhs._M_string.data()), 0, 0);
+	return *this;
+      }
+
+      void
+      swap(basic_stringbuf& __rhs) noexcept(_Noexcept_swap::value)
+      {
+	__xfer_bufptrs __l_st{*this, std::__addressof(__rhs)};
+	__xfer_bufptrs __r_st{__rhs, this};
+	__streambuf_type& __base = __rhs;
+	__streambuf_type::swap(__base);
+	__rhs.pubimbue(this->pubimbue(__rhs.getloc()));
+	std::swap(_M_mode, __rhs._M_mode);
+	std::swap(_M_string, __rhs._M_string); // XXX not exception safe
+      }
+#endif // C++11
+
+      // Getters and setters:
+
+      /**
+       *  @brief  Copying out the string buffer.
+       *  @return  A copy of one of the underlying sequences.
+       *
+       *  <em>If the buffer is only created in input mode, the underlying
+       *  character sequence is equal to the input sequence; otherwise, it
+       *  is equal to the output sequence.</em> [27.7.1.2]/1
+      */
+      __string_type
+      str() const _GLIBCXX_LVAL_REF_QUAL
+      {
+	__string_type __ret(_M_string.get_allocator());
+	if (char_type* __hi = _M_high_mark())
+	  __ret.assign(this->pbase(), __hi);
+	else
+	  __ret = _M_string;
+	return __ret;
+      }
+
+#if __cplusplus > 201703L && _GLIBCXX_USE_CXX11_ABI
+#if __cpp_concepts
+      template<__allocator_like _SAlloc>
+	basic_string<_CharT, _Traits, _SAlloc>
+	str(const _SAlloc& __sa) const
+	{
+	  auto __sv = view();
+	  return { __sv.data(), __sv.size(), __sa };
+	}
+#endif
+
+      __string_type
+      str() &&
+      {
+	if (char_type* __hi = _M_high_mark())
+	  {
+	    // Set length to end of character sequence and add null terminator.
+	    _M_string._M_set_length(_M_high_mark() - this->pbase());
+	  }
+	auto __str = std::move(_M_string);
+	_M_string.clear();
+	_M_sync(_M_string.data(), 0, 0);
+	return __str;
+      }
+
+      basic_string_view<char_type, traits_type>
+      view() const noexcept
+      {
+	if (char_type* __hi = _M_high_mark())
+	  return { this->pbase(), __hi };
+	else
+	  return _M_string;
+      }
+#endif // C++20
+
+      /**
+       *  @brief  Setting a new buffer.
+       *  @param  __s  The string to use as a new sequence.
+       *
+       *  Deallocates any previous stored sequence, then copies @a s to
+       *  use as a new one.
+      */
+      void
+      str(const __string_type& __s)
+      {
+	// Cannot use _M_string = __s, since v3 strings are COW
+	// (not always true now but assign() always works).
+	_M_string.assign(__s.data(), __s.size());
+	_M_stringbuf_init(_M_mode);
+      }
+
+#if __cplusplus > 201703L && _GLIBCXX_USE_CXX11_ABI
+#if __cpp_concepts
+      template<__allocator_like _SAlloc>
+	requires (!is_same_v<_SAlloc, _Alloc>)
+	void
+	str(const basic_string<_CharT, _Traits, _SAlloc>& __s)
+	{
+	  _M_string.assign(__s.data(), __s.size());
+	  _M_stringbuf_init(_M_mode);
+	}
+#endif
+
+      void
+      str(__string_type&& __s)
+      {
+	_M_string = std::move(__s);
+	_M_stringbuf_init(_M_mode);
+      }
+#endif
+
+    protected:
+      // Common initialization code goes here.
+      void
+      _M_stringbuf_init(ios_base::openmode __mode)
+      {
+	_M_mode = __mode;
+	__size_type __len = 0;
+	if (_M_mode & (ios_base::ate | ios_base::app))
+	  __len = _M_string.size();
+	_M_sync(const_cast<char_type*>(_M_string.data()), 0, __len);
+      }
+
+      virtual streamsize
+      showmanyc()
+      {
+	streamsize __ret = -1;
+	if (_M_mode & ios_base::in)
+	  {
+	    _M_update_egptr();
+	    __ret = this->egptr() - this->gptr();
+	  }
+	return __ret;
+      }
+
+      virtual int_type
+      underflow();
+
+      virtual int_type
+      pbackfail(int_type __c = traits_type::eof());
+
+      virtual int_type
+      overflow(int_type __c = traits_type::eof());
+
+      /**
+       *  @brief  Manipulates the buffer.
+       *  @param  __s  Pointer to a buffer area.
+       *  @param  __n  Size of @a __s.
+       *  @return  @c this
+       *
+       *  If no buffer has already been created, and both @a __s and @a __n are
+       *  non-zero, then @c __s is used as a buffer; see
+       *  https://gcc.gnu.org/onlinedocs/libstdc++/manual/streambufs.html#io.streambuf.buffering
+       *  for more.
+      */
+      virtual __streambuf_type*
+      setbuf(char_type* __s, streamsize __n)
+      {
+	if (__s && __n >= 0)
+	  {
+	    // This is implementation-defined behavior, and assumes
+	    // that an external char_type array of length __n exists
+	    // and has been pre-allocated. If this is not the case,
+	    // things will quickly blow up.
+
+	    // Step 1: Destroy the current internal array.
+	    _M_string.clear();
+
+	    // Step 2: Use the external array.
+	    _M_sync(__s, __n, 0);
+	  }
+	return this;
+      }
+
+      virtual pos_type
+      seekoff(off_type __off, ios_base::seekdir __way,
+	      ios_base::openmode __mode = ios_base::in | ios_base::out);
+
+      virtual pos_type
+      seekpos(pos_type __sp,
+	      ios_base::openmode __mode = ios_base::in | ios_base::out);
+
+      // Internal function for correctly updating the internal buffer
+      // for a particular _M_string, due to initialization or re-sizing
+      // of an existing _M_string.
+      void
+      _M_sync(char_type* __base, __size_type __i, __size_type __o);
+
+      // Internal function for correctly updating egptr() to the actual
+      // string end.
+      void
+      _M_update_egptr()
+      {
+	if (char_type* __pptr = this->pptr())
+	  {
+	    char_type* __egptr = this->egptr();
+	    if (!__egptr || __pptr > __egptr)
+	      {
+		if (_M_mode & ios_base::in)
+		  this->setg(this->eback(), this->gptr(), __pptr);
+		else
+		  this->setg(__pptr, __pptr, __pptr);
+	      }
+	  }
+      }
+
+      // Works around the issue with pbump, part of the protected
+      // interface of basic_streambuf, taking just an int.
+      void
+      _M_pbump(char_type* __pbeg, char_type* __pend, off_type __off);
+
+    private:
+      // Return a pointer to the end of the underlying character sequence.
+      // This might not be the same character as _M_string.end() because
+      // basic_stringbuf::overflow might have written to unused capacity
+      // in _M_string without updating its length.
+      __attribute__((__always_inline__))
+      char_type*
+      _M_high_mark() const _GLIBCXX_NOEXCEPT
+      {
+	if (char_type* __pptr = this->pptr())
+	  {
+	    char_type* __egptr = this->egptr();
+	    if (!__egptr || __pptr > __egptr)
+	      return __pptr;  // Underlying sequence is [pbase, pptr).
+	    else
+	      return __egptr; // Underlying sequence is [pbase, egptr).
+	  }
+	return 0; // Underlying character sequence is just _M_string.
+      }
+
+#if __cplusplus >= 201103L
+#if _GLIBCXX_USE_CXX11_ABI
+      // This type captures the state of the gptr / pptr pointers as offsets
+      // so they can be restored in another object after moving the string.
+      struct __xfer_bufptrs
+      {
+	__xfer_bufptrs(const basic_stringbuf& __from, basic_stringbuf* __to)
+	: _M_to{__to}, _M_goff{-1, -1, -1}, _M_poff{-1, -1, -1}
+	{
+	  const _CharT* const __str = __from._M_string.data();
+	  const _CharT* __end = nullptr;
+	  if (__from.eback())
+	    {
+	      _M_goff[0] = __from.eback() - __str;
+	      _M_goff[1] = __from.gptr() - __str;
+	      _M_goff[2] = __from.egptr() - __str;
+	      __end = __from.egptr();
+	    }
+	  if (__from.pbase())
+	    {
+	      _M_poff[0] = __from.pbase() - __str;
+	      _M_poff[1] = __from.pptr() - __from.pbase();
+	      _M_poff[2] = __from.epptr() - __str;
+	      if (!__end || __from.pptr() > __end)
+		__end = __from.pptr();
+	    }
+
+	  // Set _M_string length to the greater of the get and put areas.
+	  if (__end)
+	    {
+	      // The const_cast avoids changing this constructor's signature,
+	      // because it is exported from the dynamic library.
+	      auto& __mut_from = const_cast<basic_stringbuf&>(__from);
+	      __mut_from._M_string._M_length(__end - __str);
+	    }
+	}
+
+	~__xfer_bufptrs()
+	{
+	  char_type* __str = const_cast<char_type*>(_M_to->_M_string.data());
+	  if (_M_goff[0] != -1)
+	    _M_to->setg(__str+_M_goff[0], __str+_M_goff[1], __str+_M_goff[2]);
+	  if (_M_poff[0] != -1)
+	    _M_to->_M_pbump(__str+_M_poff[0], __str+_M_poff[2], _M_poff[1]);
+	}
+
+	basic_stringbuf* _M_to;
+	off_type _M_goff[3];
+	off_type _M_poff[3];
+      };
+#else
+      // This type does nothing when using Copy-On-Write strings.
+      struct __xfer_bufptrs
+      {
+	__xfer_bufptrs(const basic_stringbuf&, basic_stringbuf*) { }
+      };
+#endif
+
+      // The move constructor initializes an __xfer_bufptrs temporary then
+      // delegates to this constructor to performs moves during its lifetime.
+      basic_stringbuf(basic_stringbuf&& __rhs, __xfer_bufptrs&&)
+      : __streambuf_type(static_cast<const __streambuf_type&>(__rhs)),
+      _M_mode(__rhs._M_mode), _M_string(std::move(__rhs._M_string))
+      { }
+
+#if __cplusplus > 201703L && _GLIBCXX_USE_CXX11_ABI
+      // The move constructor initializes an __xfer_bufptrs temporary then
+      // delegates to this constructor to performs moves during its lifetime.
+      basic_stringbuf(basic_stringbuf&& __rhs, const allocator_type& __a,
+		      __xfer_bufptrs&&)
+      : __streambuf_type(static_cast<const __streambuf_type&>(__rhs)),
+      _M_mode(__rhs._M_mode), _M_string(std::move(__rhs._M_string), __a)
+      { }
+#endif
+#endif // C++11
+    };
+
+
+  // [27.7.2] Template class basic_istringstream
+  /**
+   *  @brief  Controlling input for std::string.
+   *  @ingroup io
+   *
+   *  @tparam _CharT  Type of character stream.
+   *  @tparam _Traits  Traits for character type, defaults to
+   *                   char_traits<_CharT>.
+   *  @tparam _Alloc  Allocator type, defaults to allocator<_CharT>.
+   *
+   *  This class supports reading from objects of type std::basic_string,
+   *  using the inherited functions from std::basic_istream.  To control
+   *  the associated sequence, an instance of std::basic_stringbuf is used,
+   *  which this page refers to as @c sb.
+  */
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    class basic_istringstream : public basic_istream<_CharT, _Traits>
+    {
+    public:
+      // Types:
+      typedef _CharT 					char_type;
+      typedef _Traits 					traits_type;
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 251. basic_stringbuf missing allocator_type
+      typedef _Alloc				       	allocator_type;
+      typedef typename traits_type::int_type 		int_type;
+      typedef typename traits_type::pos_type 		pos_type;
+      typedef typename traits_type::off_type 		off_type;
+
+      // Non-standard types:
+      typedef basic_string<_CharT, _Traits, _Alloc> 	__string_type;
+      typedef basic_stringbuf<_CharT, _Traits, _Alloc> 	__stringbuf_type;
+      typedef basic_istream<char_type, traits_type>	__istream_type;
+
+    private:
+      __stringbuf_type	_M_stringbuf;
+
+    public:
+      // Constructors:
+
+      /**
+       *  @brief  Default constructor starts with an empty string buffer.
+       *
+       *  Initializes @c sb using @c in, and passes @c &sb to the base
+       *  class initializer.  Does not allocate any buffer.
+       *
+       *  That's a lie.  We initialize the base class with NULL, because the
+       *  string class does its own memory management.
+      */
+      basic_istringstream()
+      : __istream_type(), _M_stringbuf(ios_base::in)
+      { this->init(&_M_stringbuf); }
+
+      /**
+       *  @brief  Starts with an empty string buffer.
+       *  @param  __mode  Whether the buffer can read, or write, or both.
+       *
+       *  @c ios_base::in is automatically included in @a __mode.
+       *
+       *  Initializes @c sb using @c __mode|in, and passes @c &sb to the base
+       *  class initializer.  Does not allocate any buffer.
+       *
+       *  That's a lie.  We initialize the base class with NULL, because the
+       *  string class does its own memory management.
+      */
+      explicit
+      basic_istringstream(ios_base::openmode __mode)
+      : __istream_type(), _M_stringbuf(__mode | ios_base::in)
+      { this->init(&_M_stringbuf); }
+
+      /**
+       *  @brief  Starts with an existing string buffer.
+       *  @param  __str  A string to copy as a starting buffer.
+       *  @param  __mode  Whether the buffer can read, or write, or both.
+       *
+       *  @c ios_base::in is automatically included in @a mode.
+       *
+       *  Initializes @c sb using @a str and @c mode|in, and passes @c &sb
+       *  to the base class initializer.
+       *
+       *  That's a lie.  We initialize the base class with NULL, because the
+       *  string class does its own memory management.
+      */
+      explicit
+      basic_istringstream(const __string_type& __str,
+			  ios_base::openmode __mode = ios_base::in)
+      : __istream_type(), _M_stringbuf(__str, __mode | ios_base::in)
+      { this->init(&_M_stringbuf); }
+
+      /**
+       *  @brief  The destructor does nothing.
+       *
+       *  The buffer is deallocated by the stringbuf object, not the
+       *  formatting stream.
+      */
+      ~basic_istringstream()
+      { }
+
+#if __cplusplus >= 201103L
+      basic_istringstream(const basic_istringstream&) = delete;
+
+      basic_istringstream(basic_istringstream&& __rhs)
+      : __istream_type(std::move(__rhs)),
+      _M_stringbuf(std::move(__rhs._M_stringbuf))
+      { __istream_type::set_rdbuf(&_M_stringbuf); }
+
+#if __cplusplus > 201703L && _GLIBCXX_USE_CXX11_ABI
+      basic_istringstream(ios_base::openmode __mode, const allocator_type& __a)
+      : __istream_type(), _M_stringbuf(__mode | ios_base::in, __a)
+      { this->init(std::__addressof(_M_stringbuf)); }
+
+      explicit
+      basic_istringstream(__string_type&& __str,
+			  ios_base::openmode __mode = ios_base::in)
+      : __istream_type(), _M_stringbuf(std::move(__str), __mode | ios_base::in)
+      { this->init(std::__addressof(_M_stringbuf)); }
+
+      template<typename _SAlloc>
+	basic_istringstream(const basic_string<_CharT, _Traits, _SAlloc>& __str,
+			    const allocator_type& __a)
+	: basic_istringstream(__str, ios_base::in, __a)
+	{ }
+
+      template<typename _SAlloc>
+	basic_istringstream(const basic_string<_CharT, _Traits, _SAlloc>& __str,
+			    ios_base::openmode __mode,
+			    const allocator_type& __a)
+	: __istream_type(), _M_stringbuf(__str, __mode | ios_base::in, __a)
+	{ this->init(std::__addressof(_M_stringbuf)); }
+
+      template<typename _SAlloc>
+	explicit
+	basic_istringstream(const basic_string<_CharT, _Traits, _SAlloc>& __str,
+			    ios_base::openmode __mode = ios_base::in)
+	: basic_istringstream(__str, __mode, allocator_type())
+	{ }
+#endif // C++20
+
+      // 27.8.3.2 Assign and swap:
+
+      basic_istringstream&
+      operator=(const basic_istringstream&) = delete;
+
+      basic_istringstream&
+      operator=(basic_istringstream&& __rhs)
+      {
+	__istream_type::operator=(std::move(__rhs));
+	_M_stringbuf = std::move(__rhs._M_stringbuf);
+	return *this;
+      }
+
+      void
+      swap(basic_istringstream& __rhs)
+      {
+	__istream_type::swap(__rhs);
+	_M_stringbuf.swap(__rhs._M_stringbuf);
+      }
+#endif // C++11
+
+      // Members:
+      /**
+       *  @brief  Accessing the underlying buffer.
+       *  @return  The current basic_stringbuf buffer.
+       *
+       *  This hides both signatures of std::basic_ios::rdbuf().
+      */
+      __stringbuf_type*
+      rdbuf() const
+      { return const_cast<__stringbuf_type*>(&_M_stringbuf); }
+
+      /**
+       *  @brief  Copying out the string buffer.
+       *  @return  @c rdbuf()->str()
+      */
+      __string_type
+      str() const _GLIBCXX_LVAL_REF_QUAL
+      { return _M_stringbuf.str(); }
+
+#if __cplusplus > 201703L && _GLIBCXX_USE_CXX11_ABI
+#if __cpp_concepts
+      template<__allocator_like _SAlloc>
+	basic_string<_CharT, _Traits, _SAlloc>
+	str(const _SAlloc& __sa) const
+	{ return _M_stringbuf.str(__sa); }
+#endif
+
+      __string_type
+      str() &&
+      { return std::move(_M_stringbuf).str(); }
+
+      basic_string_view<char_type, traits_type>
+      view() const noexcept
+      { return _M_stringbuf.view(); }
+#endif
+
+      /**
+       *  @brief  Setting a new buffer.
+       *  @param  __s  The string to use as a new sequence.
+       *
+       *  Calls @c rdbuf()->str(s).
+      */
+      void
+      str(const __string_type& __s)
+      { _M_stringbuf.str(__s); }
+
+#if __cplusplus > 201703L && _GLIBCXX_USE_CXX11_ABI
+#if __cpp_concepts
+      template<__allocator_like _SAlloc>
+	requires (!is_same_v<_SAlloc, _Alloc>)
+	void
+	str(const basic_string<_CharT, _Traits, _SAlloc>& __s)
+	{ _M_stringbuf.str(__s); }
+#endif
+
+      void
+      str(__string_type&& __s)
+      { _M_stringbuf.str(std::move(__s)); }
+#endif
+    };
+
+
+  // [27.7.3] Template class basic_ostringstream
+  /**
+   *  @brief  Controlling output for std::string.
+   *  @ingroup io
+   *
+   *  @tparam _CharT  Type of character stream.
+   *  @tparam _Traits  Traits for character type, defaults to
+   *                   char_traits<_CharT>.
+   *  @tparam _Alloc  Allocator type, defaults to allocator<_CharT>.
+   *
+   *  This class supports writing to objects of type std::basic_string,
+   *  using the inherited functions from std::basic_ostream.  To control
+   *  the associated sequence, an instance of std::basic_stringbuf is used,
+   *  which this page refers to as @c sb.
+  */
+  template <typename _CharT, typename _Traits, typename _Alloc>
+    class basic_ostringstream : public basic_ostream<_CharT, _Traits>
+    {
+    public:
+      // Types:
+      typedef _CharT 					char_type;
+      typedef _Traits 					traits_type;
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 251. basic_stringbuf missing allocator_type
+      typedef _Alloc				       	allocator_type;
+      typedef typename traits_type::int_type 		int_type;
+      typedef typename traits_type::pos_type 		pos_type;
+      typedef typename traits_type::off_type 		off_type;
+
+      // Non-standard types:
+      typedef basic_string<_CharT, _Traits, _Alloc> 	__string_type;
+      typedef basic_stringbuf<_CharT, _Traits, _Alloc> 	__stringbuf_type;
+      typedef basic_ostream<char_type, traits_type>	__ostream_type;
+
+    private:
+      __stringbuf_type	_M_stringbuf;
+
+    public:
+      // Constructors/destructor:
+
+      /**
+       *  @brief  Default constructor starts with an empty string buffer.
+       *
+       *  Initializes @c sb using @c mode|out, and passes @c &sb to the base
+       *  class initializer.  Does not allocate any buffer.
+       *
+       *  That's a lie.  We initialize the base class with NULL, because the
+       *  string class does its own memory management.
+      */
+      basic_ostringstream()
+      : __ostream_type(), _M_stringbuf(ios_base::out)
+      { this->init(&_M_stringbuf); }
+
+      /**
+       *  @brief  Starts with an empty string buffer.
+       *  @param  __mode  Whether the buffer can read, or write, or both.
+       *
+       *  @c ios_base::out is automatically included in @a mode.
+       *
+       *  Initializes @c sb using @c mode|out, and passes @c &sb to the base
+       *  class initializer.  Does not allocate any buffer.
+       *
+       *  That's a lie.  We initialize the base class with NULL, because the
+       *  string class does its own memory management.
+      */
+      explicit
+      basic_ostringstream(ios_base::openmode __mode)
+      : __ostream_type(), _M_stringbuf(__mode | ios_base::out)
+      { this->init(&_M_stringbuf); }
+
+      /**
+       *  @brief  Starts with an existing string buffer.
+       *  @param  __str  A string to copy as a starting buffer.
+       *  @param  __mode  Whether the buffer can read, or write, or both.
+       *
+       *  @c ios_base::out is automatically included in @a mode.
+       *
+       *  Initializes @c sb using @a str and @c mode|out, and passes @c &sb
+       *  to the base class initializer.
+       *
+       *  That's a lie.  We initialize the base class with NULL, because the
+       *  string class does its own memory management.
+      */
+      explicit
+      basic_ostringstream(const __string_type& __str,
+			  ios_base::openmode __mode = ios_base::out)
+      : __ostream_type(), _M_stringbuf(__str, __mode | ios_base::out)
+      { this->init(&_M_stringbuf); }
+
+      /**
+       *  @brief  The destructor does nothing.
+       *
+       *  The buffer is deallocated by the stringbuf object, not the
+       *  formatting stream.
+      */
+      ~basic_ostringstream()
+      { }
+
+#if __cplusplus >= 201103L
+      basic_ostringstream(const basic_ostringstream&) = delete;
+
+      basic_ostringstream(basic_ostringstream&& __rhs)
+      : __ostream_type(std::move(__rhs)),
+      _M_stringbuf(std::move(__rhs._M_stringbuf))
+      { __ostream_type::set_rdbuf(&_M_stringbuf); }
+
+#if __cplusplus > 201703L && _GLIBCXX_USE_CXX11_ABI
+      basic_ostringstream(ios_base::openmode __mode, const allocator_type& __a)
+      : __ostream_type(), _M_stringbuf(__mode | ios_base::out, __a)
+      { this->init(std::__addressof(_M_stringbuf)); }
+
+      explicit
+      basic_ostringstream(__string_type&& __str,
+			  ios_base::openmode __mode = ios_base::out)
+      : __ostream_type(), _M_stringbuf(std::move(__str), __mode | ios_base::out)
+      { this->init(std::__addressof(_M_stringbuf)); }
+
+      template<typename _SAlloc>
+	basic_ostringstream(const basic_string<_CharT, _Traits, _SAlloc>& __str,
+			    const allocator_type& __a)
+	: basic_ostringstream(__str, ios_base::out, __a)
+	{ }
+
+      template<typename _SAlloc>
+	basic_ostringstream(const basic_string<_CharT, _Traits, _SAlloc>& __str,
+			    ios_base::openmode __mode,
+			    const allocator_type& __a)
+	: __ostream_type(), _M_stringbuf(__str, __mode | ios_base::out, __a)
+	{ this->init(std::__addressof(_M_stringbuf)); }
+
+      template<typename _SAlloc>
+	explicit
+	basic_ostringstream(const basic_string<_CharT, _Traits, _SAlloc>& __str,
+			    ios_base::openmode __mode = ios_base::out)
+	: basic_ostringstream(__str, __mode, allocator_type())
+	{ }
+#endif // C++20
+
+      // 27.8.3.2 Assign and swap:
+
+      basic_ostringstream&
+      operator=(const basic_ostringstream&) = delete;
+
+      basic_ostringstream&
+      operator=(basic_ostringstream&& __rhs)
+      {
+	__ostream_type::operator=(std::move(__rhs));
+	_M_stringbuf = std::move(__rhs._M_stringbuf);
+	return *this;
+      }
+
+      void
+      swap(basic_ostringstream& __rhs)
+      {
+	__ostream_type::swap(__rhs);
+	_M_stringbuf.swap(__rhs._M_stringbuf);
+      }
+#endif // C++11
+
+      // Members:
+      /**
+       *  @brief  Accessing the underlying buffer.
+       *  @return  The current basic_stringbuf buffer.
+       *
+       *  This hides both signatures of std::basic_ios::rdbuf().
+      */
+      __stringbuf_type*
+      rdbuf() const
+      { return const_cast<__stringbuf_type*>(&_M_stringbuf); }
+
+      /**
+       *  @brief  Copying out the string buffer.
+       *  @return  @c rdbuf()->str()
+      */
+      __string_type
+      str() const _GLIBCXX_LVAL_REF_QUAL
+      { return _M_stringbuf.str(); }
+
+#if __cplusplus > 201703L && _GLIBCXX_USE_CXX11_ABI
+#if __cpp_concepts
+      template<__allocator_like _SAlloc>
+	basic_string<_CharT, _Traits, _SAlloc>
+	str(const _SAlloc& __sa) const
+	{ return _M_stringbuf.str(__sa); }
+#endif
+
+      __string_type
+      str() &&
+      { return std::move(_M_stringbuf).str(); }
+
+      basic_string_view<char_type, traits_type>
+      view() const noexcept
+      { return _M_stringbuf.view(); }
+#endif
+
+      /**
+       *  @brief  Setting a new buffer.
+       *  @param  __s  The string to use as a new sequence.
+       *
+       *  Calls @c rdbuf()->str(s).
+      */
+      void
+      str(const __string_type& __s)
+      { _M_stringbuf.str(__s); }
+
+#if __cplusplus > 201703L && _GLIBCXX_USE_CXX11_ABI
+#if __cpp_concepts
+      template<__allocator_like _SAlloc>
+	requires (!is_same_v<_SAlloc, _Alloc>)
+	void
+	str(const basic_string<_CharT, _Traits, _SAlloc>& __s)
+	{ _M_stringbuf.str(__s); }
+#endif
+
+      void
+      str(__string_type&& __s)
+      { _M_stringbuf.str(std::move(__s)); }
+#endif
+    };
+
+
+  // [27.7.4] Template class basic_stringstream
+  /**
+   *  @brief  Controlling input and output for std::string.
+   *  @ingroup io
+   *
+   *  @tparam _CharT  Type of character stream.
+   *  @tparam _Traits  Traits for character type, defaults to
+   *                   char_traits<_CharT>.
+   *  @tparam _Alloc  Allocator type, defaults to allocator<_CharT>.
+   *
+   *  This class supports reading from and writing to objects of type
+   *  std::basic_string, using the inherited functions from
+   *  std::basic_iostream.  To control the associated sequence, an instance
+   *  of std::basic_stringbuf is used, which this page refers to as @c sb.
+  */
+  template <typename _CharT, typename _Traits, typename _Alloc>
+    class basic_stringstream : public basic_iostream<_CharT, _Traits>
+    {
+    public:
+      // Types:
+      typedef _CharT 					char_type;
+      typedef _Traits 					traits_type;
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 251. basic_stringbuf missing allocator_type
+      typedef _Alloc				       	allocator_type;
+      typedef typename traits_type::int_type 		int_type;
+      typedef typename traits_type::pos_type 		pos_type;
+      typedef typename traits_type::off_type 		off_type;
+
+      // Non-standard Types:
+      typedef basic_string<_CharT, _Traits, _Alloc> 	__string_type;
+      typedef basic_stringbuf<_CharT, _Traits, _Alloc> 	__stringbuf_type;
+      typedef basic_iostream<char_type, traits_type>	__iostream_type;
+
+    private:
+      __stringbuf_type	_M_stringbuf;
+
+    public:
+      // Constructors/destructors
+
+      /**
+       *  @brief  Default constructor starts with an empty string buffer.
+       *
+       *  Initializes @c sb using the mode @c in|out, and passes @c &sb
+       *  to the base class initializer.  Does not allocate any buffer.
+       *
+       *  That's a lie.  We initialize the base class with NULL, because the
+       *  string class does its own memory management.
+      */
+      basic_stringstream()
+      : __iostream_type(), _M_stringbuf(ios_base::out | ios_base::in)
+      { this->init(&_M_stringbuf); }
+
+      /**
+       *  @brief  Starts with an empty string buffer.
+       *  @param  __m  Whether the buffer can read, or write, or both.
+       *
+       *  Initializes @c sb using the mode from @c __m, and passes @c &sb
+       *  to the base class initializer.  Does not allocate any buffer.
+       *
+       *  That's a lie.  We initialize the base class with NULL, because the
+       *  string class does its own memory management.
+      */
+      explicit
+      basic_stringstream(ios_base::openmode __m)
+      : __iostream_type(), _M_stringbuf(__m)
+      { this->init(&_M_stringbuf); }
+
+      /**
+       *  @brief  Starts with an existing string buffer.
+       *  @param  __str  A string to copy as a starting buffer.
+       *  @param  __m  Whether the buffer can read, or write, or both.
+       *
+       *  Initializes @c sb using @a __str and @c __m, and passes @c &sb
+       *  to the base class initializer.
+       *
+       *  That's a lie.  We initialize the base class with NULL, because the
+       *  string class does its own memory management.
+      */
+      explicit
+      basic_stringstream(const __string_type& __str,
+			 ios_base::openmode __m = ios_base::out | ios_base::in)
+      : __iostream_type(), _M_stringbuf(__str, __m)
+      { this->init(&_M_stringbuf); }
+
+      /**
+       *  @brief  The destructor does nothing.
+       *
+       *  The buffer is deallocated by the stringbuf object, not the
+       *  formatting stream.
+      */
+      ~basic_stringstream()
+      { }
+
+#if __cplusplus >= 201103L
+      basic_stringstream(const basic_stringstream&) = delete;
+
+      basic_stringstream(basic_stringstream&& __rhs)
+      : __iostream_type(std::move(__rhs)),
+      _M_stringbuf(std::move(__rhs._M_stringbuf))
+      { __iostream_type::set_rdbuf(&_M_stringbuf); }
+
+#if __cplusplus > 201703L && _GLIBCXX_USE_CXX11_ABI
+      basic_stringstream(ios_base::openmode __mode, const allocator_type& __a)
+      : __iostream_type(), _M_stringbuf(__mode, __a)
+      { this->init(&_M_stringbuf); }
+
+      explicit
+      basic_stringstream(__string_type&& __str,
+			 ios_base::openmode __mode = ios_base::in
+						     | ios_base::out)
+      : __iostream_type(), _M_stringbuf(std::move(__str), __mode)
+      { this->init(std::__addressof(_M_stringbuf)); }
+
+      template<typename _SAlloc>
+	basic_stringstream(const basic_string<_CharT, _Traits, _SAlloc>& __str,
+			   const allocator_type& __a)
+	: basic_stringstream(__str, ios_base::in | ios_base::out, __a)
+	{ }
+
+      template<typename _SAlloc>
+	basic_stringstream(const basic_string<_CharT, _Traits, _SAlloc>& __str,
+			   ios_base::openmode __mode,
+			   const allocator_type& __a)
+	: __iostream_type(), _M_stringbuf(__str, __mode, __a)
+	{ this->init(std::__addressof(_M_stringbuf)); }
+
+      template<typename _SAlloc>
+	explicit
+	basic_stringstream(const basic_string<_CharT, _Traits, _SAlloc>& __str,
+			   ios_base::openmode __mode = ios_base::in
+						       | ios_base::out)
+	: basic_stringstream(__str, __mode, allocator_type())
+	{ }
+#endif // C++20
+
+      // 27.8.3.2 Assign and swap:
+
+      basic_stringstream&
+      operator=(const basic_stringstream&) = delete;
+
+      basic_stringstream&
+      operator=(basic_stringstream&& __rhs)
+      {
+	__iostream_type::operator=(std::move(__rhs));
+	_M_stringbuf = std::move(__rhs._M_stringbuf);
+	return *this;
+      }
+
+      void
+      swap(basic_stringstream& __rhs)
+      {
+	__iostream_type::swap(__rhs);
+	_M_stringbuf.swap(__rhs._M_stringbuf);
+      }
+#endif // C++11
+
+      // Members:
+      /**
+       *  @brief  Accessing the underlying buffer.
+       *  @return  The current basic_stringbuf buffer.
+       *
+       *  This hides both signatures of std::basic_ios::rdbuf().
+      */
+      __stringbuf_type*
+      rdbuf() const
+      { return const_cast<__stringbuf_type*>(&_M_stringbuf); }
+
+      /**
+       *  @brief  Copying out the string buffer.
+       *  @return  @c rdbuf()->str()
+      */
+      __string_type
+      str() const _GLIBCXX_LVAL_REF_QUAL
+      { return _M_stringbuf.str(); }
+
+#if __cplusplus > 201703L && _GLIBCXX_USE_CXX11_ABI
+#if __cpp_concepts
+      template<__allocator_like _SAlloc>
+	basic_string<_CharT, _Traits, _SAlloc>
+	str(const _SAlloc& __sa) const
+	{ return _M_stringbuf.str(__sa); }
+#endif
+
+      __string_type
+      str() &&
+      { return std::move(_M_stringbuf).str(); }
+
+      basic_string_view<char_type, traits_type>
+      view() const noexcept
+      { return _M_stringbuf.view(); }
+#endif
+
+      /**
+       *  @brief  Setting a new buffer.
+       *  @param  __s  The string to use as a new sequence.
+       *
+       *  Calls @c rdbuf()->str(s).
+      */
+      void
+      str(const __string_type& __s)
+      { _M_stringbuf.str(__s); }
+
+#if __cplusplus > 201703L && _GLIBCXX_USE_CXX11_ABI
+#if __cpp_concepts
+      template<__allocator_like _SAlloc>
+	requires (!is_same_v<_SAlloc, _Alloc>)
+	void
+	str(const basic_string<_CharT, _Traits, _SAlloc>& __s)
+	{ _M_stringbuf.str(__s); }
+#endif
+
+      void
+      str(__string_type&& __s)
+      { _M_stringbuf.str(std::move(__s)); }
+#endif
+    };
+
+#if __cplusplus >= 201103L
+  /// Swap specialization for stringbufs.
+  template <class _CharT, class _Traits, class _Allocator>
+    inline void
+    swap(basic_stringbuf<_CharT, _Traits, _Allocator>& __x,
+	 basic_stringbuf<_CharT, _Traits, _Allocator>& __y)
+    noexcept(noexcept(__x.swap(__y)))
+    { __x.swap(__y); }
+
+  /// Swap specialization for istringstreams.
+  template <class _CharT, class _Traits, class _Allocator>
+    inline void
+    swap(basic_istringstream<_CharT, _Traits, _Allocator>& __x,
+	 basic_istringstream<_CharT, _Traits, _Allocator>& __y)
+    { __x.swap(__y); }
+
+  /// Swap specialization for ostringstreams.
+  template <class _CharT, class _Traits, class _Allocator>
+    inline void
+    swap(basic_ostringstream<_CharT, _Traits, _Allocator>& __x,
+	 basic_ostringstream<_CharT, _Traits, _Allocator>& __y)
+    { __x.swap(__y); }
+
+  /// Swap specialization for stringstreams.
+  template <class _CharT, class _Traits, class _Allocator>
+    inline void
+    swap(basic_stringstream<_CharT, _Traits, _Allocator>& __x,
+	 basic_stringstream<_CharT, _Traits, _Allocator>& __y)
+    { __x.swap(__y); }
+#endif // C++11
+
+_GLIBCXX_END_NAMESPACE_CXX11
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#undef _GLIBCXX_LVAL_REF_QUAL
+
+#include <bits/sstream.tcc>
+
+#endif /* _GLIBCXX_SSTREAM */
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@stack b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@stack
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@@ -0,0 +1,63 @@
+// <stack> -*- C++ -*-
+
+// Copyright (C) 2001-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/*
+ *
+ * Copyright (c) 1994
+ * Hewlett-Packard Company
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Hewlett-Packard Company makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ *
+ *
+ * Copyright (c) 1996,1997
+ * Silicon Graphics Computer Systems, Inc.
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Silicon Graphics makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ */
+
+/** @file include/stack
+ *  This is a Standard C++ Library header.
+ */
+
+#ifndef _GLIBCXX_STACK
+#define _GLIBCXX_STACK 1
+
+#pragma GCC system_header
+
+#include <deque>
+#include <bits/stl_stack.h>
+
+#endif /* _GLIBCXX_STACK */
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@@ -0,0 +1,307 @@
+// Standard exception classes  -*- C++ -*-
+
+// Copyright (C) 2001-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file include/stdexcept
+ *  This is a Standard C++ Library header.
+ */
+
+//
+// ISO C++ 19.1  Exception classes
+//
+
+#ifndef _GLIBCXX_STDEXCEPT
+#define _GLIBCXX_STDEXCEPT 1
+
+#pragma GCC system_header
+
+#include <exception>
+#include <string>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+#if _GLIBCXX_USE_DUAL_ABI
+#if _GLIBCXX_USE_CXX11_ABI
+  // Emulates an old COW string when the new std::string is in use.
+  struct __cow_string
+  {
+    union {
+      const char* _M_p;
+      char _M_bytes[sizeof(const char*)];
+    };
+
+    __cow_string();
+    __cow_string(const std::string&);
+    __cow_string(const char*, size_t);
+    __cow_string(const __cow_string&) _GLIBCXX_NOTHROW;
+    __cow_string& operator=(const __cow_string&) _GLIBCXX_NOTHROW;
+    ~__cow_string();
+#if __cplusplus >= 201103L
+    __cow_string(__cow_string&&) noexcept;
+    __cow_string& operator=(__cow_string&&) noexcept;
+#endif
+  };
+
+  typedef basic_string<char> __sso_string;
+#else // _GLIBCXX_USE_CXX11_ABI
+  typedef basic_string<char> __cow_string;
+
+  // Emulates a new SSO string when the old std::string is in use.
+  struct __sso_string
+  {
+    struct __str
+    {
+      const char* _M_p;
+      size_t _M_string_length;
+      char _M_local_buf[16];
+    };
+
+    union {
+      __str _M_s;
+      char _M_bytes[sizeof(__str)];
+    };
+
+    __sso_string() _GLIBCXX_NOTHROW;
+    __sso_string(const std::string&);
+    __sso_string(const char*, size_t);
+    __sso_string(const __sso_string&);
+    __sso_string& operator=(const __sso_string&);
+    ~__sso_string();
+#if __cplusplus >= 201103L
+    __sso_string(__sso_string&&) noexcept;
+    __sso_string& operator=(__sso_string&&) noexcept;
+#endif
+  };
+#endif // _GLIBCXX_USE_CXX11_ABI
+#else  // _GLIBCXX_USE_DUAL_ABI
+  typedef basic_string<char> __sso_string;
+  typedef basic_string<char> __cow_string;
+#endif
+
+  /**
+   * @addtogroup exceptions
+   * @{
+   */
+
+  /** Logic errors represent problems in the internal logic of a program;
+   *  in theory, these are preventable, and even detectable before the
+   *  program runs (e.g., violations of class invariants).
+   *  @brief One of two subclasses of exception.
+   */
+  class logic_error : public exception
+  {
+    __cow_string _M_msg;
+
+  public:
+    /** Takes a character string describing the error.  */
+    explicit
+    logic_error(const string& __arg) _GLIBCXX_TXN_SAFE;
+
+#if __cplusplus >= 201103L
+    explicit
+    logic_error(const char*) _GLIBCXX_TXN_SAFE;
+
+    logic_error(logic_error&&) noexcept;
+    logic_error& operator=(logic_error&&) noexcept;
+#endif
+
+#if _GLIBCXX_USE_CXX11_ABI || _GLIBCXX_DEFINE_STDEXCEPT_COPY_OPS
+    logic_error(const logic_error&) _GLIBCXX_NOTHROW;
+    logic_error& operator=(const logic_error&) _GLIBCXX_NOTHROW;
+#elif __cplusplus >= 201103L
+    logic_error(const logic_error&) = default;
+    logic_error& operator=(const logic_error&) = default;
+#endif
+
+    virtual ~logic_error() _GLIBCXX_TXN_SAFE_DYN _GLIBCXX_NOTHROW;
+
+    /** Returns a C-style character string describing the general cause of
+     *  the current error (the same string passed to the ctor).  */
+    virtual const char*
+    what() const _GLIBCXX_TXN_SAFE_DYN _GLIBCXX_NOTHROW;
+
+# ifdef _GLIBCXX_TM_TS_INTERNAL
+    friend void*
+    ::_txnal_logic_error_get_msg(void* e);
+# endif
+  };
+
+  /** Thrown by the library, or by you, to report domain errors (domain in
+   *  the mathematical sense).  */
+  class domain_error : public logic_error
+  {
+  public:
+    explicit domain_error(const string& __arg) _GLIBCXX_TXN_SAFE;
+#if __cplusplus >= 201103L
+    explicit domain_error(const char*) _GLIBCXX_TXN_SAFE;
+    domain_error(const domain_error&) = default;
+    domain_error& operator=(const domain_error&) = default;
+    domain_error(domain_error&&) = default;
+    domain_error& operator=(domain_error&&) = default;
+#endif
+    virtual ~domain_error() _GLIBCXX_NOTHROW;
+  };
+
+  /** Thrown to report invalid arguments to functions.  */
+  class invalid_argument : public logic_error
+  {
+  public:
+    explicit invalid_argument(const string& __arg) _GLIBCXX_TXN_SAFE;
+#if __cplusplus >= 201103L
+    explicit invalid_argument(const char*) _GLIBCXX_TXN_SAFE;
+    invalid_argument(const invalid_argument&) = default;
+    invalid_argument& operator=(const invalid_argument&) = default;
+    invalid_argument(invalid_argument&&) = default;
+    invalid_argument& operator=(invalid_argument&&) = default;
+#endif
+    virtual ~invalid_argument() _GLIBCXX_NOTHROW;
+  };
+
+  /** Thrown when an object is constructed that would exceed its maximum
+   *  permitted size (e.g., a basic_string instance).  */
+  class length_error : public logic_error
+  {
+  public:
+    explicit length_error(const string& __arg) _GLIBCXX_TXN_SAFE;
+#if __cplusplus >= 201103L
+    explicit length_error(const char*) _GLIBCXX_TXN_SAFE;
+    length_error(const length_error&) = default;
+    length_error& operator=(const length_error&) = default;
+    length_error(length_error&&) = default;
+    length_error& operator=(length_error&&) = default;
+#endif
+    virtual ~length_error() _GLIBCXX_NOTHROW;
+  };
+
+  /** This represents an argument whose value is not within the expected
+   *  range (e.g., boundary checks in basic_string).  */
+  class out_of_range : public logic_error
+  {
+  public:
+    explicit out_of_range(const string& __arg) _GLIBCXX_TXN_SAFE;
+#if __cplusplus >= 201103L
+    explicit out_of_range(const char*) _GLIBCXX_TXN_SAFE;
+    out_of_range(const out_of_range&) = default;
+    out_of_range& operator=(const out_of_range&) = default;
+    out_of_range(out_of_range&&) = default;
+    out_of_range& operator=(out_of_range&&) = default;
+#endif
+    virtual ~out_of_range() _GLIBCXX_NOTHROW;
+  };
+
+  /** Runtime errors represent problems outside the scope of a program;
+   *  they cannot be easily predicted and can generally only be caught as
+   *  the program executes.
+   *  @brief One of two subclasses of exception.
+   */
+  class runtime_error : public exception
+  {
+    __cow_string _M_msg;
+
+  public:
+    /** Takes a character string describing the error.  */
+    explicit
+    runtime_error(const string& __arg) _GLIBCXX_TXN_SAFE;
+
+#if __cplusplus >= 201103L
+    explicit
+    runtime_error(const char*) _GLIBCXX_TXN_SAFE;
+
+    runtime_error(runtime_error&&) noexcept;
+    runtime_error& operator=(runtime_error&&) noexcept;
+#endif
+
+#if _GLIBCXX_USE_CXX11_ABI || _GLIBCXX_DEFINE_STDEXCEPT_COPY_OPS
+    runtime_error(const runtime_error&) _GLIBCXX_NOTHROW;
+    runtime_error& operator=(const runtime_error&) _GLIBCXX_NOTHROW;
+#elif __cplusplus >= 201103L
+    runtime_error(const runtime_error&) = default;
+    runtime_error& operator=(const runtime_error&) = default;
+#endif
+
+    virtual ~runtime_error() _GLIBCXX_TXN_SAFE_DYN _GLIBCXX_NOTHROW;
+
+    /** Returns a C-style character string describing the general cause of
+     *  the current error (the same string passed to the ctor).  */
+    virtual const char*
+    what() const _GLIBCXX_TXN_SAFE_DYN _GLIBCXX_NOTHROW;
+
+# ifdef _GLIBCXX_TM_TS_INTERNAL
+    friend void*
+    ::_txnal_runtime_error_get_msg(void* e);
+# endif
+  };
+
+  /** Thrown to indicate range errors in internal computations.  */
+  class range_error : public runtime_error
+  {
+  public:
+    explicit range_error(const string& __arg) _GLIBCXX_TXN_SAFE;
+#if __cplusplus >= 201103L
+    explicit range_error(const char*) _GLIBCXX_TXN_SAFE;
+    range_error(const range_error&) = default;
+    range_error& operator=(const range_error&) = default;
+    range_error(range_error&&) = default;
+    range_error& operator=(range_error&&) = default;
+#endif
+    virtual ~range_error() _GLIBCXX_NOTHROW;
+  };
+
+  /** Thrown to indicate arithmetic overflow.  */
+  class overflow_error : public runtime_error
+  {
+  public:
+    explicit overflow_error(const string& __arg) _GLIBCXX_TXN_SAFE;
+#if __cplusplus >= 201103L
+    explicit overflow_error(const char*) _GLIBCXX_TXN_SAFE;
+    overflow_error(const overflow_error&) = default;
+    overflow_error& operator=(const overflow_error&) = default;
+    overflow_error(overflow_error&&) = default;
+    overflow_error& operator=(overflow_error&&) = default;
+#endif
+    virtual ~overflow_error() _GLIBCXX_NOTHROW;
+  };
+
+  /** Thrown to indicate arithmetic underflow.  */
+  class underflow_error : public runtime_error
+  {
+  public:
+    explicit underflow_error(const string& __arg) _GLIBCXX_TXN_SAFE;
+#if __cplusplus >= 201103L
+    explicit underflow_error(const char*) _GLIBCXX_TXN_SAFE;
+    underflow_error(const underflow_error&) = default;
+    underflow_error& operator=(const underflow_error&) = default;
+    underflow_error(underflow_error&&) = default;
+    underflow_error& operator=(underflow_error&&) = default;
+#endif
+    virtual ~underflow_error() _GLIBCXX_NOTHROW;
+  };
+
+  /// @} group exceptions
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif /* _GLIBCXX_STDEXCEPT */
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@streambuf b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@streambuf
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@@ -0,0 +1,860 @@
+// Stream buffer classes -*- C++ -*-
+
+// Copyright (C) 1997-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file include/streambuf
+ *  This is a Standard C++ Library header.
+ */
+
+//
+// ISO C++ 14882: 27.5  Stream buffers
+//
+
+#ifndef _GLIBXX_STREAMBUF
+#define _GLIBXX_STREAMBUF 1
+
+#pragma GCC system_header
+
+#include <bits/c++config.h>
+#include <iosfwd>
+#include <bits/localefwd.h>
+#include <bits/ios_base.h>
+#include <bits/cpp_type_traits.h>
+#include <ext/type_traits.h>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+#define _IsUnused __attribute__ ((__unused__))
+
+  template<typename _CharT, typename _Traits>
+    streamsize
+    __copy_streambufs_eof(basic_streambuf<_CharT, _Traits>*,
+			  basic_streambuf<_CharT, _Traits>*, bool&);
+
+  /**
+   *  @brief  The actual work of input and output (interface).
+   *  @ingroup io
+   *
+   *  @tparam _CharT  Type of character stream.
+   *  @tparam _Traits  Traits for character type, defaults to
+   *                   char_traits<_CharT>.
+   *
+   *  This is a base class.  Derived stream buffers each control a
+   *  pair of character sequences:  one for input, and one for output.
+   *
+   *  Section [27.5.1] of the standard describes the requirements and
+   *  behavior of stream buffer classes.  That section (three paragraphs)
+   *  is reproduced here, for simplicity and accuracy.
+   *
+   *  -# Stream buffers can impose various constraints on the sequences
+   *     they control.  Some constraints are:
+   *     - The controlled input sequence can be not readable.
+   *     - The controlled output sequence can be not writable.
+   *     - The controlled sequences can be associated with the contents of
+   *       other representations for character sequences, such as external
+   *       files.
+   *     - The controlled sequences can support operations @e directly to or
+   *       from associated sequences.
+   *     - The controlled sequences can impose limitations on how the
+   *       program can read characters from a sequence, write characters to
+   *       a sequence, put characters back into an input sequence, or alter
+   *       the stream position.
+   *     .
+   *  -# Each sequence is characterized by three pointers which, if non-null,
+   *     all point into the same @c charT array object.  The array object
+   *     represents, at any moment, a (sub)sequence of characters from the
+   *     sequence.  Operations performed on a sequence alter the values
+   *     stored in these pointers, perform reads and writes directly to or
+   *     from associated sequences, and alter <em>the stream position</em> and
+   *     conversion state as needed to maintain this subsequence relationship.
+   *     The three pointers are:
+   *     - the <em>beginning pointer</em>, or lowest element address in the
+   *       array (called @e xbeg here);
+   *     - the <em>next pointer</em>, or next element address that is a
+   *       current candidate for reading or writing (called @e xnext here);
+   *     - the <em>end pointer</em>, or first element address beyond the
+   *       end of the array (called @e xend here).
+   *     .
+   *  -# The following semantic constraints shall always apply for any set
+   *     of three pointers for a sequence, using the pointer names given
+   *     immediately above:
+   *     - If @e xnext is not a null pointer, then @e xbeg and @e xend shall
+   *       also be non-null pointers into the same @c charT array, as
+   *       described above; otherwise, @e xbeg and @e xend shall also be null.
+   *     - If @e xnext is not a null pointer and @e xnext < @e xend for an
+   *       output sequence, then a <em>write position</em> is available.
+   *       In this case, @e *xnext shall be assignable as the next element
+   *       to write (to put, or to store a character value, into the sequence).
+   *     - If @e xnext is not a null pointer and @e xbeg < @e xnext for an
+   *       input sequence, then a <em>putback position</em> is available.
+   *       In this case, @e xnext[-1] shall have a defined value and is the
+   *       next (preceding) element to store a character that is put back
+   *       into the input sequence.
+   *     - If @e xnext is not a null pointer and @e xnext< @e xend for an
+   *       input sequence, then a <em>read position</em> is available.
+   *       In this case, @e *xnext shall have a defined value and is the
+   *       next element to read (to get, or to obtain a character value,
+   *       from the sequence).
+  */
+  template<typename _CharT, typename _Traits>
+    class basic_streambuf
+    {
+    public:
+      ///@{
+      /**
+       *  These are standard types.  They permit a standardized way of
+       *  referring to names of (or names dependent on) the template
+       *  parameters, which are specific to the implementation.
+      */
+      typedef _CharT 					char_type;
+      typedef _Traits 					traits_type;
+      typedef typename traits_type::int_type 		int_type;
+      typedef typename traits_type::pos_type 		pos_type;
+      typedef typename traits_type::off_type 		off_type;
+      ///@}
+
+      ///@{
+      /// This is a non-standard type.
+      typedef basic_streambuf<char_type, traits_type>  	__streambuf_type;
+      ///@}
+
+      friend class basic_ios<char_type, traits_type>;
+      friend class basic_istream<char_type, traits_type>;
+      friend class basic_ostream<char_type, traits_type>;
+      friend class istreambuf_iterator<char_type, traits_type>;
+      friend class ostreambuf_iterator<char_type, traits_type>;
+
+      friend streamsize
+      __copy_streambufs_eof<>(basic_streambuf*, basic_streambuf*, bool&);
+
+      template<bool _IsMove, typename _CharT2>
+        friend typename __gnu_cxx::__enable_if<__is_char<_CharT2>::__value,
+					       _CharT2*>::__type
+        __copy_move_a2(istreambuf_iterator<_CharT2>,
+		       istreambuf_iterator<_CharT2>, _CharT2*);
+
+      template<typename _CharT2>
+        friend typename __gnu_cxx::__enable_if<__is_char<_CharT2>::__value,
+				  istreambuf_iterator<_CharT2> >::__type
+        find(istreambuf_iterator<_CharT2>, istreambuf_iterator<_CharT2>,
+	     const _CharT2&);
+
+      template<typename _CharT2, typename _Distance>
+        friend typename __gnu_cxx::__enable_if<__is_char<_CharT2>::__value,
+					       void>::__type
+        advance(istreambuf_iterator<_CharT2>&, _Distance);
+
+      friend void __istream_extract(istream&, char*, streamsize);
+
+      template<typename _CharT2, typename _Traits2, typename _Alloc>
+        friend basic_istream<_CharT2, _Traits2>&
+        operator>>(basic_istream<_CharT2, _Traits2>&,
+		   basic_string<_CharT2, _Traits2, _Alloc>&);
+
+      template<typename _CharT2, typename _Traits2, typename _Alloc>
+        friend basic_istream<_CharT2, _Traits2>&
+        getline(basic_istream<_CharT2, _Traits2>&,
+		basic_string<_CharT2, _Traits2, _Alloc>&, _CharT2);
+
+    protected:
+      /*
+       *  This is based on _IO_FILE, just reordered to be more consistent,
+       *  and is intended to be the most minimal abstraction for an
+       *  internal buffer.
+       *  -  get == input == read
+       *  -  put == output == write
+      */
+      char_type* 		_M_in_beg;     ///< Start of get area.
+      char_type* 		_M_in_cur;     ///< Current read area.
+      char_type* 		_M_in_end;     ///< End of get area.
+      char_type* 		_M_out_beg;    ///< Start of put area.
+      char_type* 		_M_out_cur;    ///< Current put area.
+      char_type* 		_M_out_end;    ///< End of put area.
+
+      /// Current locale setting.
+      locale 			_M_buf_locale;
+
+  public:
+      /// Destructor deallocates no buffer space.
+      virtual
+      ~basic_streambuf()
+      { }
+
+      // [27.5.2.2.1] locales
+      /**
+       *  @brief  Entry point for imbue().
+       *  @param  __loc  The new locale.
+       *  @return  The previous locale.
+       *
+       *  Calls the derived imbue(__loc).
+      */
+      locale
+      pubimbue(const locale& __loc)
+      {
+	locale __tmp(this->getloc());
+	this->imbue(__loc);
+	_M_buf_locale = __loc;
+	return __tmp;
+      }
+
+      /**
+       *  @brief  Locale access.
+       *  @return  The current locale in effect.
+       *
+       *  If pubimbue(loc) has been called, then the most recent @c loc
+       *  is returned.  Otherwise the global locale in effect at the time
+       *  of construction is returned.
+      */
+      locale
+      getloc() const
+      { return _M_buf_locale; }
+
+      // [27.5.2.2.2] buffer management and positioning
+      ///@{
+      /**
+       *  @brief  Entry points for derived buffer functions.
+       *
+       *  The public versions of @c pubfoo dispatch to the protected
+       *  derived @c foo member functions, passing the arguments (if any)
+       *  and returning the result unchanged.
+      */
+      basic_streambuf*
+      pubsetbuf(char_type* __s, streamsize __n)
+      { return this->setbuf(__s, __n); }
+
+      /**
+       *  @brief  Alters the stream position.
+       *  @param  __off  Offset.
+       *  @param  __way  Value for ios_base::seekdir.
+       *  @param  __mode Value for ios_base::openmode.
+       *
+       *  Calls virtual seekoff function.
+      */
+      pos_type
+      pubseekoff(off_type __off, ios_base::seekdir __way,
+		 ios_base::openmode __mode = ios_base::in | ios_base::out)
+      { return this->seekoff(__off, __way, __mode); }
+
+      /**
+       *  @brief  Alters the stream position.
+       *  @param  __sp  Position
+       *  @param  __mode Value for ios_base::openmode.
+       *
+       *  Calls virtual seekpos function.
+      */
+      pos_type
+      pubseekpos(pos_type __sp,
+		 ios_base::openmode __mode = ios_base::in | ios_base::out)
+      { return this->seekpos(__sp, __mode); }
+
+      /**
+       *  @brief  Calls virtual sync function.
+      */
+      int
+      pubsync() { return this->sync(); }
+      ///@}
+
+      // [27.5.2.2.3] get area
+      /**
+       *  @brief  Looking ahead into the stream.
+       *  @return  The number of characters available.
+       *
+       *  If a read position is available, returns the number of characters
+       *  available for reading before the buffer must be refilled.
+       *  Otherwise returns the derived @c showmanyc().
+      */
+      streamsize
+      in_avail()
+      {
+	const streamsize __ret = this->egptr() - this->gptr();
+	return __ret ? __ret : this->showmanyc();
+      }
+
+      /**
+       *  @brief  Getting the next character.
+       *  @return  The next character, or eof.
+       *
+       *  Calls @c sbumpc(), and if that function returns
+       *  @c traits::eof(), so does this function.  Otherwise, @c sgetc().
+      */
+      int_type
+      snextc()
+      {
+	int_type __ret = traits_type::eof();
+	if (__builtin_expect(!traits_type::eq_int_type(this->sbumpc(),
+						       __ret), true))
+	  __ret = this->sgetc();
+	return __ret;
+      }
+
+      /**
+       *  @brief  Getting the next character.
+       *  @return  The next character, or eof.
+       *
+       *  If the input read position is available, returns that character
+       *  and increments the read pointer, otherwise calls and returns
+       *  @c uflow().
+      */
+      int_type
+      sbumpc()
+      {
+	int_type __ret;
+	if (__builtin_expect(this->gptr() < this->egptr(), true))
+	  {
+	    __ret = traits_type::to_int_type(*this->gptr());
+	    this->gbump(1);
+	  }
+	else
+	  __ret = this->uflow();
+	return __ret;
+      }
+
+      /**
+       *  @brief  Getting the next character.
+       *  @return  The next character, or eof.
+       *
+       *  If the input read position is available, returns that character,
+       *  otherwise calls and returns @c underflow().  Does not move the
+       *  read position after fetching the character.
+      */
+      int_type
+      sgetc()
+      {
+	int_type __ret;
+	if (__builtin_expect(this->gptr() < this->egptr(), true))
+	  __ret = traits_type::to_int_type(*this->gptr());
+	else
+	  __ret = this->underflow();
+	return __ret;
+      }
+
+      /**
+       *  @brief  Entry point for xsgetn.
+       *  @param  __s  A buffer area.
+       *  @param  __n  A count.
+       *
+       *  Returns xsgetn(__s,__n).  The effect is to fill @a __s[0] through
+       *  @a __s[__n-1] with characters from the input sequence, if possible.
+      */
+      streamsize
+      sgetn(char_type* __s, streamsize __n)
+      { return this->xsgetn(__s, __n); }
+
+      // [27.5.2.2.4] putback
+      /**
+       *  @brief  Pushing characters back into the input stream.
+       *  @param  __c  The character to push back.
+       *  @return  The previous character, if possible.
+       *
+       *  Similar to sungetc(), but @a __c is pushed onto the stream
+       *  instead of <em>the previous character.</em> If successful,
+       *  the next character fetched from the input stream will be @a
+       *  __c.
+      */
+      int_type
+      sputbackc(char_type __c)
+      {
+	int_type __ret;
+	const bool __testpos = this->eback() < this->gptr();
+	if (__builtin_expect(!__testpos ||
+			     !traits_type::eq(__c, this->gptr()[-1]), false))
+	  __ret = this->pbackfail(traits_type::to_int_type(__c));
+	else
+	  {
+	    this->gbump(-1);
+	    __ret = traits_type::to_int_type(*this->gptr());
+	  }
+	return __ret;
+      }
+
+      /**
+       *  @brief  Moving backwards in the input stream.
+       *  @return  The previous character, if possible.
+       *
+       *  If a putback position is available, this function decrements
+       *  the input pointer and returns that character.  Otherwise,
+       *  calls and returns pbackfail().  The effect is to @a unget
+       *  the last character @a gotten.
+      */
+      int_type
+      sungetc()
+      {
+	int_type __ret;
+	if (__builtin_expect(this->eback() < this->gptr(), true))
+	  {
+	    this->gbump(-1);
+	    __ret = traits_type::to_int_type(*this->gptr());
+	  }
+	else
+	  __ret = this->pbackfail();
+	return __ret;
+      }
+
+      // [27.5.2.2.5] put area
+      /**
+       *  @brief  Entry point for all single-character output functions.
+       *  @param  __c  A character to output.
+       *  @return  @a __c, if possible.
+       *
+       *  One of two public output functions.
+       *
+       *  If a write position is available for the output sequence (i.e.,
+       *  the buffer is not full), stores @a __c in that position, increments
+       *  the position, and returns @c traits::to_int_type(__c).  If a write
+       *  position is not available, returns @c overflow(__c).
+      */
+      int_type
+      sputc(char_type __c)
+      {
+	int_type __ret;
+	if (__builtin_expect(this->pptr() < this->epptr(), true))
+	  {
+	    *this->pptr() = __c;
+	    this->pbump(1);
+	    __ret = traits_type::to_int_type(__c);
+	  }
+	else
+	  __ret = this->overflow(traits_type::to_int_type(__c));
+	return __ret;
+      }
+
+      /**
+       *  @brief  Entry point for all single-character output functions.
+       *  @param  __s  A buffer read area.
+       *  @param  __n  A count.
+       *
+       *  One of two public output functions.
+       *
+       *
+       *  Returns xsputn(__s,__n).  The effect is to write @a __s[0] through
+       *  @a __s[__n-1] to the output sequence, if possible.
+      */
+      streamsize
+      sputn(const char_type* __s, streamsize __n)
+      { return this->xsputn(__s, __n); }
+
+    protected:
+      /**
+       *  @brief  Base constructor.
+       *
+       *  Only called from derived constructors, and sets up all the
+       *  buffer data to zero, including the pointers described in the
+       *  basic_streambuf class description.  Note that, as a result,
+       *  - the class starts with no read nor write positions available,
+       *  - this is not an error
+      */
+      basic_streambuf()
+      : _M_in_beg(0), _M_in_cur(0), _M_in_end(0),
+      _M_out_beg(0), _M_out_cur(0), _M_out_end(0),
+      _M_buf_locale(locale())
+      { }
+
+      // [27.5.2.3.1] get area access
+      ///@{
+      /**
+       *  @brief  Access to the get area.
+       *
+       *  These functions are only available to other protected functions,
+       *  including derived classes.
+       *
+       *  - eback() returns the beginning pointer for the input sequence
+       *  - gptr() returns the next pointer for the input sequence
+       *  - egptr() returns the end pointer for the input sequence
+      */
+      char_type*
+      eback() const { return _M_in_beg; }
+
+      char_type*
+      gptr()  const { return _M_in_cur;  }
+
+      char_type*
+      egptr() const { return _M_in_end; }
+      ///@}
+
+      /**
+       *  @brief  Moving the read position.
+       *  @param  __n  The delta by which to move.
+       *
+       *  This just advances the read position without returning any data.
+      */
+      void
+      gbump(int __n) { _M_in_cur += __n; }
+
+      /**
+       *  @brief  Setting the three read area pointers.
+       *  @param  __gbeg  A pointer.
+       *  @param  __gnext  A pointer.
+       *  @param  __gend  A pointer.
+       *  @post  @a __gbeg == @c eback(), @a __gnext == @c gptr(), and
+       *         @a __gend == @c egptr()
+      */
+      void
+      setg(char_type* __gbeg, char_type* __gnext, char_type* __gend)
+      {
+	_M_in_beg = __gbeg;
+	_M_in_cur = __gnext;
+	_M_in_end = __gend;
+      }
+
+      // [27.5.2.3.2] put area access
+      ///@{
+      /**
+       *  @brief  Access to the put area.
+       *
+       *  These functions are only available to other protected functions,
+       *  including derived classes.
+       *
+       *  - pbase() returns the beginning pointer for the output sequence
+       *  - pptr() returns the next pointer for the output sequence
+       *  - epptr() returns the end pointer for the output sequence
+      */
+      char_type*
+      pbase() const { return _M_out_beg; }
+
+      char_type*
+      pptr() const { return _M_out_cur; }
+
+      char_type*
+      epptr() const { return _M_out_end; }
+      ///@}
+
+      /**
+       *  @brief  Moving the write position.
+       *  @param  __n  The delta by which to move.
+       *
+       *  This just advances the write position without returning any data.
+      */
+      void
+      pbump(int __n) { _M_out_cur += __n; }
+
+      /**
+       *  @brief  Setting the three write area pointers.
+       *  @param  __pbeg  A pointer.
+       *  @param  __pend  A pointer.
+       *  @post  @a __pbeg == @c pbase(), @a __pbeg == @c pptr(), and
+       *         @a __pend == @c epptr()
+      */
+      void
+      setp(char_type* __pbeg, char_type* __pend)
+      {
+	_M_out_beg = _M_out_cur = __pbeg;
+	_M_out_end = __pend;
+      }
+
+      // [27.5.2.4] virtual functions
+      // [27.5.2.4.1] locales
+      /**
+       *  @brief  Changes translations.
+       *  @param  __loc  A new locale.
+       *
+       *  Translations done during I/O which depend on the current
+       *  locale are changed by this call.  The standard adds,
+       *  <em>Between invocations of this function a class derived
+       *  from streambuf can safely cache results of calls to locale
+       *  functions and to members of facets so obtained.</em>
+       *
+       *  @note  Base class version does nothing.
+      */
+      virtual void
+      imbue(const locale& __loc _IsUnused)
+      { }
+
+      // [27.5.2.4.2] buffer management and positioning
+      /**
+       *  @brief  Manipulates the buffer.
+       *
+       *  Each derived class provides its own appropriate behavior.  See
+       *  the next-to-last paragraph of
+       *  https://gcc.gnu.org/onlinedocs/libstdc++/manual/streambufs.html#io.streambuf.buffering
+       *  for more on this function.
+       *
+       *  @note  Base class version does nothing, returns @c this.
+      */
+      virtual basic_streambuf<char_type,_Traits>*
+      setbuf(char_type*, streamsize)
+      {	return this; }
+
+      /**
+       *  @brief  Alters the stream positions.
+       *
+       *  Each derived class provides its own appropriate behavior.
+       *  @note  Base class version does nothing, returns a @c pos_type
+       *         that represents an invalid stream position.
+      */
+      virtual pos_type
+      seekoff(off_type, ios_base::seekdir,
+	      ios_base::openmode /*__mode*/ = ios_base::in | ios_base::out)
+      { return pos_type(off_type(-1)); }
+
+      /**
+       *  @brief  Alters the stream positions.
+       *
+       *  Each derived class provides its own appropriate behavior.
+       *  @note  Base class version does nothing, returns a @c pos_type
+       *         that represents an invalid stream position.
+      */
+      virtual pos_type
+      seekpos(pos_type,
+	      ios_base::openmode /*__mode*/ = ios_base::in | ios_base::out)
+      { return pos_type(off_type(-1)); }
+
+      /**
+       *  @brief  Synchronizes the buffer arrays with the controlled sequences.
+       *  @return  -1 on failure.
+       *
+       *  Each derived class provides its own appropriate behavior,
+       *  including the definition of @a failure.
+       *  @note  Base class version does nothing, returns zero.
+      */
+      virtual int
+      sync() { return 0; }
+
+      // [27.5.2.4.3] get area
+      /**
+       *  @brief  Investigating the data available.
+       *  @return  An estimate of the number of characters available in the
+       *           input sequence, or -1.
+       *
+       *  <em>If it returns a positive value, then successive calls to
+       *  @c underflow() will not return @c traits::eof() until at
+       *  least that number of characters have been supplied.  If @c
+       *  showmanyc() returns -1, then calls to @c underflow() or @c
+       *  uflow() will fail.</em> [27.5.2.4.3]/1
+       *
+       *  @note  Base class version does nothing, returns zero.
+       *  @note  The standard adds that <em>the intention is not only that the
+       *         calls [to underflow or uflow] will not return @c eof() but
+       *         that they will return immediately.</em>
+       *  @note  The standard adds that <em>the morphemes of @c showmanyc are
+       *         @b es-how-many-see, not @b show-manic.</em>
+      */
+      virtual streamsize
+      showmanyc() { return 0; }
+
+      /**
+       *  @brief  Multiple character extraction.
+       *  @param  __s  A buffer area.
+       *  @param  __n  Maximum number of characters to assign.
+       *  @return  The number of characters assigned.
+       *
+       *  Fills @a __s[0] through @a __s[__n-1] with characters from the input
+       *  sequence, as if by @c sbumpc().  Stops when either @a __n characters
+       *  have been copied, or when @c traits::eof() would be copied.
+       *
+       *  It is expected that derived classes provide a more efficient
+       *  implementation by overriding this definition.
+      */
+      virtual streamsize
+      xsgetn(char_type* __s, streamsize __n);
+
+      /**
+       *  @brief  Fetches more data from the controlled sequence.
+       *  @return  The first character from the <em>pending sequence</em>.
+       *
+       *  Informally, this function is called when the input buffer is
+       *  exhausted (or does not exist, as buffering need not actually be
+       *  done).  If a buffer exists, it is @a refilled.  In either case, the
+       *  next available character is returned, or @c traits::eof() to
+       *  indicate a null pending sequence.
+       *
+       *  For a formal definition of the pending sequence, see a good text
+       *  such as Langer & Kreft, or [27.5.2.4.3]/7-14.
+       *
+       *  A functioning input streambuf can be created by overriding only
+       *  this function (no buffer area will be used).  For an example, see
+       *  https://gcc.gnu.org/onlinedocs/libstdc++/manual/streambufs.html
+       *
+       *  @note  Base class version does nothing, returns eof().
+      */
+      virtual int_type
+      underflow()
+      { return traits_type::eof(); }
+
+      /**
+       *  @brief  Fetches more data from the controlled sequence.
+       *  @return  The first character from the <em>pending sequence</em>.
+       *
+       *  Informally, this function does the same thing as @c underflow(),
+       *  and in fact is required to call that function.  It also returns
+       *  the new character, like @c underflow() does.  However, this
+       *  function also moves the read position forward by one.
+      */
+      virtual int_type
+      uflow()
+      {
+	int_type __ret = traits_type::eof();
+	const bool __testeof = traits_type::eq_int_type(this->underflow(),
+							__ret);
+	if (!__testeof)
+	  {
+	    __ret = traits_type::to_int_type(*this->gptr());
+	    this->gbump(1);
+	  }
+	return __ret;
+      }
+
+      // [27.5.2.4.4] putback
+      /**
+       *  @brief  Tries to back up the input sequence.
+       *  @param  __c  The character to be inserted back into the sequence.
+       *  @return  eof() on failure, <em>some other value</em> on success
+       *  @post  The constraints of @c gptr(), @c eback(), and @c pptr()
+       *         are the same as for @c underflow().
+       *
+       *  @note  Base class version does nothing, returns eof().
+      */
+      virtual int_type
+      pbackfail(int_type __c _IsUnused  = traits_type::eof())
+      { return traits_type::eof(); }
+
+      // Put area:
+      /**
+       *  @brief  Multiple character insertion.
+       *  @param  __s  A buffer area.
+       *  @param  __n  Maximum number of characters to write.
+       *  @return  The number of characters written.
+       *
+       *  Writes @a __s[0] through @a __s[__n-1] to the output sequence, as if
+       *  by @c sputc().  Stops when either @a n characters have been
+       *  copied, or when @c sputc() would return @c traits::eof().
+       *
+       *  It is expected that derived classes provide a more efficient
+       *  implementation by overriding this definition.
+      */
+      virtual streamsize
+      xsputn(const char_type* __s, streamsize __n);
+
+      /**
+       *  @brief  Consumes data from the buffer; writes to the
+       *          controlled sequence.
+       *  @param  __c  An additional character to consume.
+       *  @return  eof() to indicate failure, something else (usually
+       *           @a __c, or not_eof())
+       *
+       *  Informally, this function is called when the output buffer
+       *  is full (or does not exist, as buffering need not actually
+       *  be done).  If a buffer exists, it is @a consumed, with
+       *  <em>some effect</em> on the controlled sequence.
+       *  (Typically, the buffer is written out to the sequence
+       *  verbatim.)  In either case, the character @a c is also
+       *  written out, if @a __c is not @c eof().
+       *
+       *  For a formal definition of this function, see a good text
+       *  such as Langer & Kreft, or [27.5.2.4.5]/3-7.
+       *
+       *  A functioning output streambuf can be created by overriding only
+       *  this function (no buffer area will be used).
+       *
+       *  @note  Base class version does nothing, returns eof().
+      */
+      virtual int_type
+      overflow(int_type __c _IsUnused  = traits_type::eof())
+      { return traits_type::eof(); }
+
+#if _GLIBCXX_USE_DEPRECATED && __cplusplus <= 201402L
+    // Annex D.6 (removed in C++17)
+    public:
+      /**
+       *  @brief  Tosses a character.
+       *
+       *  Advances the read pointer, ignoring the character that would have
+       *  been read.
+       *
+       *  See http://gcc.gnu.org/ml/libstdc++/2002-05/msg00168.html
+       */
+      _GLIBCXX_DEPRECATED_SUGGEST("std::basic_streambuf::sbumpc")
+      void
+      stossc()
+      {
+	if (this->gptr() < this->egptr())
+	  this->gbump(1);
+	else
+	  this->uflow();
+      }
+#endif
+
+      // Also used by specializations for char and wchar_t in src.
+      void
+      __safe_gbump(streamsize __n) { _M_in_cur += __n; }
+
+      void
+      __safe_pbump(streamsize __n) { _M_out_cur += __n; }
+
+#if __cplusplus < 201103L
+    private:
+#else
+    protected:
+#endif
+      basic_streambuf(const basic_streambuf&);
+
+      basic_streambuf&
+      operator=(const basic_streambuf&);
+
+#if __cplusplus >= 201103L
+      void
+      swap(basic_streambuf& __sb)
+      {
+	std::swap(_M_in_beg, __sb._M_in_beg);
+	std::swap(_M_in_cur, __sb._M_in_cur);
+	std::swap(_M_in_end, __sb._M_in_end);
+	std::swap(_M_out_beg, __sb._M_out_beg);
+	std::swap(_M_out_cur, __sb._M_out_cur);
+	std::swap(_M_out_end, __sb._M_out_end);
+	std::swap(_M_buf_locale, __sb._M_buf_locale);
+      }
+#endif
+    };
+
+#if __cplusplus >= 201103L
+  template<typename _CharT, typename _Traits>
+    std::basic_streambuf<_CharT, _Traits>::
+    basic_streambuf(const basic_streambuf&) = default;
+
+  template<typename _CharT, typename _Traits>
+    std::basic_streambuf<_CharT, _Traits>&
+    std::basic_streambuf<_CharT, _Traits>::
+    operator=(const basic_streambuf&) = default;
+#endif
+
+  // Explicit specialization declarations, defined in src/streambuf.cc.
+  template<>
+    streamsize
+    __copy_streambufs_eof(basic_streambuf<char>* __sbin,
+			  basic_streambuf<char>* __sbout, bool& __ineof);
+#ifdef _GLIBCXX_USE_WCHAR_T
+  template<>
+    streamsize
+    __copy_streambufs_eof(basic_streambuf<wchar_t>* __sbin,
+			  basic_streambuf<wchar_t>* __sbout, bool& __ineof);
+#endif
+
+#undef _IsUnused
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#include <bits/streambuf.tcc>
+
+#endif /* _GLIBCXX_STREAMBUF */
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@string b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@string
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--- /dev/null
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@@ -0,0 +1,149 @@
+// Components for manipulating sequences of characters -*- C++ -*-
+
+// Copyright (C) 1997-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file include/string
+ *  This is a Standard C++ Library header.
+ */
+
+//
+// ISO C++ 14882: 21  Strings library
+//
+
+#ifndef _GLIBCXX_STRING
+#define _GLIBCXX_STRING	1
+
+#pragma GCC system_header
+
+#include <bits/c++config.h>
+#include <bits/stringfwd.h>
+#include <bits/char_traits.h>  // NB: In turn includes stl_algobase.h
+#include <bits/allocator.h>
+#include <bits/cpp_type_traits.h>
+#include <bits/localefwd.h>    // For operators >>, <<, and getline.
+#include <bits/ostream_insert.h>
+#include <bits/stl_iterator_base_types.h>
+#include <bits/stl_iterator_base_funcs.h>
+#include <bits/stl_iterator.h>
+#include <bits/stl_function.h> // For less
+#include <ext/numeric_traits.h>
+#include <bits/stl_algobase.h>
+#include <bits/refwrap.h>
+#include <bits/range_access.h>
+#include <bits/basic_string.h>
+#include <bits/basic_string.tcc>
+
+#if __cplusplus >= 201703L && _GLIBCXX_USE_CXX11_ABI
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+  namespace pmr {
+    template<typename _Tp> class polymorphic_allocator;
+    template<typename _CharT, typename _Traits = char_traits<_CharT>>
+      using basic_string = std::basic_string<_CharT, _Traits,
+					     polymorphic_allocator<_CharT>>;
+    using string    = basic_string<char>;
+#ifdef _GLIBCXX_USE_CHAR8_T
+    using u8string  = basic_string<char8_t>;
+#endif
+    using u16string = basic_string<char16_t>;
+    using u32string = basic_string<char32_t>;
+    using wstring   = basic_string<wchar_t>;
+  } // namespace pmr
+
+  template<typename _Str>
+    struct __hash_string_base
+    : public __hash_base<size_t, _Str>
+    {
+      size_t
+      operator()(const _Str& __s) const noexcept
+      { return hash<basic_string_view<typename _Str::value_type>>{}(__s); }
+    };
+
+  template<>
+    struct hash<pmr::string>
+    : public __hash_string_base<pmr::string>
+    { };
+#ifdef _GLIBCXX_USE_CHAR8_T
+  template<>
+    struct hash<pmr::u8string>
+    : public __hash_string_base<pmr::u8string>
+    { };
+#endif
+  template<>
+    struct hash<pmr::u16string>
+    : public __hash_string_base<pmr::u16string>
+    { };
+  template<>
+    struct hash<pmr::u32string>
+    : public __hash_string_base<pmr::u32string>
+    { };
+  template<>
+    struct hash<pmr::wstring>
+    : public __hash_string_base<pmr::wstring>
+    { };
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+#endif // C++17
+
+#if __cplusplus > 201703L
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+#define __cpp_lib_erase_if 202002L
+
+  template<typename _CharT, typename _Traits, typename _Alloc,
+	   typename _Predicate>
+    _GLIBCXX20_CONSTEXPR
+    inline typename basic_string<_CharT, _Traits, _Alloc>::size_type
+    erase_if(basic_string<_CharT, _Traits, _Alloc>& __cont, _Predicate __pred)
+    {
+      using namespace __gnu_cxx;
+      const auto __osz = __cont.size();
+      const auto __end = __cont.end();
+      auto __removed = std::__remove_if(__cont.begin(), __end,
+					__ops::__pred_iter(std::ref(__pred)));
+      __cont.erase(__removed, __end);
+      return __osz - __cont.size();
+    }
+
+  template<typename _CharT, typename _Traits, typename _Alloc, typename _Up>
+    _GLIBCXX20_CONSTEXPR
+    inline typename basic_string<_CharT, _Traits, _Alloc>::size_type
+    erase(basic_string<_CharT, _Traits, _Alloc>& __cont, const _Up& __value)
+    {
+      using namespace __gnu_cxx;
+      const auto __osz = __cont.size();
+      const auto __end = __cont.end();
+      auto __removed = std::__remove_if(__cont.begin(), __end,
+					__ops::__iter_equals_val(__value));
+      __cont.erase(__removed, __end);
+      return __osz - __cont.size();
+    }
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+#endif // C++20
+
+#endif /* _GLIBCXX_STRING */
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@system_error b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@system_error
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--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@system_error
@@ -0,0 +1,531 @@
+// <system_error> -*- C++ -*-
+
+// Copyright (C) 2007-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file include/system_error
+ *  This is a Standard C++ Library header.
+ */
+
+#ifndef _GLIBCXX_SYSTEM_ERROR
+#define _GLIBCXX_SYSTEM_ERROR 1
+
+#pragma GCC system_header
+
+#if __cplusplus < 201103L
+# include <bits/c++0x_warning.h>
+#else
+
+#include <bits/c++config.h>
+#include <bits/error_constants.h>
+#include <iosfwd>
+#include <stdexcept>
+#if __cplusplus > 201703L
+# include <compare>
+#endif
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /** @addtogroup diagnostics
+   * @{
+   */
+
+  class error_code;
+  class error_condition;
+  class system_error;
+
+  /// is_error_code_enum
+  template<typename _Tp>
+    struct is_error_code_enum : public false_type { };
+
+  /// is_error_condition_enum
+  template<typename _Tp>
+    struct is_error_condition_enum : public false_type { };
+
+  template<>
+    struct is_error_condition_enum<errc>
+    : public true_type { };
+
+#if __cplusplus > 201402L
+  template <typename _Tp>
+    inline constexpr bool is_error_code_enum_v =
+      is_error_code_enum<_Tp>::value;
+  template <typename _Tp>
+    inline constexpr bool is_error_condition_enum_v =
+      is_error_condition_enum<_Tp>::value;
+#endif // C++17
+  /// @}
+
+  inline namespace _V2 {
+
+  /** @addtogroup diagnostics
+   * @{
+   */
+
+  /** Abstract base class for types defining a category of error codes.
+   *
+   * An error category defines a context that give meaning to the integer
+   * stored in an `error_code` or `error_condition` object. For example,
+   * the standard `errno` constants such a `EINVAL` and `ENOMEM` are
+   * associated with the "generic" category and other OS-specific error
+   * numbers are associated with the "system" category, but a user-defined
+   * category might give different meanings to the same numerical values.
+   *
+   * @since C++11
+   */
+  class error_category
+  {
+  public:
+    constexpr error_category() noexcept = default;
+
+    virtual ~error_category();
+
+    error_category(const error_category&) = delete;
+    error_category& operator=(const error_category&) = delete;
+
+    virtual const char*
+    name() const noexcept = 0;
+
+    // We need two different virtual functions here, one returning a
+    // COW string and one returning an SSO string. Their positions in the
+    // vtable must be consistent for dynamic dispatch to work, but which one
+    // the name "message()" finds depends on which ABI the caller is using.
+#if _GLIBCXX_USE_CXX11_ABI
+  private:
+    _GLIBCXX_DEFAULT_ABI_TAG
+    virtual __cow_string
+    _M_message(int) const;
+
+  public:
+    _GLIBCXX_DEFAULT_ABI_TAG
+    virtual string
+    message(int) const = 0;
+#else
+    virtual string
+    message(int) const = 0;
+
+  private:
+    virtual __sso_string
+    _M_message(int) const;
+#endif
+
+  public:
+    virtual error_condition
+    default_error_condition(int __i) const noexcept;
+
+    virtual bool
+    equivalent(int __i, const error_condition& __cond) const noexcept;
+
+    virtual bool
+    equivalent(const error_code& __code, int __i) const noexcept;
+
+    bool
+    operator==(const error_category& __other) const noexcept
+    { return this == &__other; }
+
+#if __cpp_lib_three_way_comparison
+    strong_ordering
+    operator<=>(const error_category& __rhs) const noexcept
+    { return std::compare_three_way()(this, &__rhs); }
+#else
+    bool
+    operator!=(const error_category& __other) const noexcept
+    { return this != &__other; }
+
+    bool
+    operator<(const error_category& __other) const noexcept
+    { return less<const error_category*>()(this, &__other); }
+#endif
+  };
+
+  // DR 890.
+
+  /// Error category for `errno` error codes.
+  _GLIBCXX_CONST const error_category& generic_category() noexcept;
+
+  /// Error category for other error codes defined by the OS.
+  _GLIBCXX_CONST const error_category& system_category() noexcept;
+
+  /// @}
+  } // end inline namespace
+
+  /** @addtogroup diagnostics
+   * @{
+   */
+
+  error_code make_error_code(errc) noexcept;
+
+  /** Class error_code
+   *
+   * This class is a value type storing an integer error number and a
+   * category that gives meaning to the error number. Typically this is done
+   * close the the point where the error happens, to capture the original
+   * error value.
+   *
+   * An `error_code` object can be used to store the original error value
+   * emitted by some subsystem, with a category relevant to the subsystem.
+   * For example, errors from POSIX library functions can be represented by
+   * an `errno` value and the "generic" category, but errors from an HTTP
+   * library might be represented by an HTTP response status code (e.g. 404)
+   * and a custom category defined by the library.
+   *
+   * @since C++11
+   * @ingroup diagnostics
+   */
+  class error_code
+  {
+  public:
+    error_code() noexcept
+    : _M_value(0), _M_cat(&system_category()) { }
+
+    error_code(int __v, const error_category& __cat) noexcept
+    : _M_value(__v), _M_cat(&__cat) { }
+
+    template<typename _ErrorCodeEnum, typename = typename
+	     enable_if<is_error_code_enum<_ErrorCodeEnum>::value>::type>
+      error_code(_ErrorCodeEnum __e) noexcept
+      { *this = make_error_code(__e); }
+
+    void
+    assign(int __v, const error_category& __cat) noexcept
+    {
+      _M_value = __v;
+      _M_cat = &__cat;
+    }
+
+    void
+    clear() noexcept
+    { assign(0, system_category()); }
+
+    // DR 804.
+    template<typename _ErrorCodeEnum>
+      typename enable_if<is_error_code_enum<_ErrorCodeEnum>::value,
+			 error_code&>::type
+      operator=(_ErrorCodeEnum __e) noexcept
+      { return *this = make_error_code(__e); }
+
+    int
+    value() const noexcept { return _M_value; }
+
+    const error_category&
+    category() const noexcept { return *_M_cat; }
+
+    error_condition
+    default_error_condition() const noexcept;
+
+    _GLIBCXX_DEFAULT_ABI_TAG
+    string
+    message() const
+    { return category().message(value()); }
+
+    explicit operator bool() const noexcept
+    { return _M_value != 0; }
+
+    // DR 804.
+  private:
+    int            		_M_value;
+    const error_category* 	_M_cat;
+  };
+
+  // 19.4.2.6 non-member functions
+
+  /// @relates error_code @{
+
+  inline error_code
+  make_error_code(errc __e) noexcept
+  { return error_code(static_cast<int>(__e), generic_category()); }
+
+#if __cpp_lib_three_way_comparison
+  inline strong_ordering
+  operator<=>(const error_code& __lhs, const error_code& __rhs) noexcept
+  {
+    if (auto __c = __lhs.category() <=> __rhs.category(); __c != 0)
+      return __c;
+    return __lhs.value() <=> __rhs.value();
+  }
+#else
+  inline bool
+  operator<(const error_code& __lhs, const error_code& __rhs) noexcept
+  {
+    return (__lhs.category() < __rhs.category()
+	    || (__lhs.category() == __rhs.category()
+		&& __lhs.value() < __rhs.value()));
+  }
+#endif
+
+  template<typename _CharT, typename _Traits>
+    basic_ostream<_CharT, _Traits>&
+    operator<<(basic_ostream<_CharT, _Traits>& __os, const error_code& __e)
+    { return (__os << __e.category().name() << ':' << __e.value()); }
+
+  /// @}
+
+  error_condition make_error_condition(errc) noexcept;
+
+  /** Class error_condition
+   *
+   * This class represents error conditions that may be visible at an API
+   * boundary. Different `error_code` values that can occur within a library
+   * or module might map to the same `error_condition`.
+   *
+   * An `error_condition` represents something that the program can test for,
+   * and subsequently take appropriate action.
+   *
+   * @since C++11
+   */
+  class error_condition
+  {
+  public:
+    error_condition() noexcept
+    : _M_value(0), _M_cat(&generic_category()) { }
+
+    error_condition(int __v, const error_category& __cat) noexcept
+    : _M_value(__v), _M_cat(&__cat) { }
+
+    template<typename _ErrorConditionEnum, typename = typename
+	 enable_if<is_error_condition_enum<_ErrorConditionEnum>::value>::type>
+      error_condition(_ErrorConditionEnum __e) noexcept
+      { *this = make_error_condition(__e); }
+
+    void
+    assign(int __v, const error_category& __cat) noexcept
+    {
+      _M_value = __v;
+      _M_cat = &__cat;
+    }
+
+    // DR 804.
+    template<typename _ErrorConditionEnum>
+      typename enable_if<is_error_condition_enum
+			 <_ErrorConditionEnum>::value, error_condition&>::type
+      operator=(_ErrorConditionEnum __e) noexcept
+      { return *this = make_error_condition(__e); }
+
+    void
+    clear() noexcept
+    { assign(0, generic_category()); }
+
+    // 19.4.3.4 observers
+    int
+    value() const noexcept { return _M_value; }
+
+    const error_category&
+    category() const noexcept { return *_M_cat; }
+
+    _GLIBCXX_DEFAULT_ABI_TAG
+    string
+    message() const
+    { return category().message(value()); }
+
+    explicit operator bool() const noexcept
+    { return _M_value != 0; }
+
+    // DR 804.
+  private:
+    int 			_M_value;
+    const error_category* 	_M_cat;
+  };
+
+  // 19.4.3.6 non-member functions
+
+  /// Create an `error_condition` representing a standard `errc` condition.
+  /// @relates error_condition
+  inline error_condition
+  make_error_condition(errc __e) noexcept
+  { return error_condition(static_cast<int>(__e), generic_category()); }
+
+  // 19.4.4 Comparison operators
+
+  /// @relates error_code
+  inline bool
+  operator==(const error_code& __lhs, const error_code& __rhs) noexcept
+  { return (__lhs.category() == __rhs.category()
+	    && __lhs.value() == __rhs.value()); }
+
+  /// @relates error_code
+  inline bool
+  operator==(const error_code& __lhs, const error_condition& __rhs) noexcept
+  {
+    return (__lhs.category().equivalent(__lhs.value(), __rhs)
+	    || __rhs.category().equivalent(__lhs, __rhs.value()));
+  }
+
+  /// @relates error_condition
+  inline bool
+  operator==(const error_condition& __lhs,
+	     const error_condition& __rhs) noexcept
+  {
+    return (__lhs.category() == __rhs.category()
+	    && __lhs.value() == __rhs.value());
+  }
+
+#if __cpp_lib_three_way_comparison
+  /// Define an ordering for error_condition objects.
+  /// @relates error_condition
+  inline strong_ordering
+  operator<=>(const error_condition& __lhs,
+	      const error_condition& __rhs) noexcept
+  {
+    if (auto __c = __lhs.category() <=> __rhs.category(); __c != 0)
+      return __c;
+    return __lhs.value() <=> __rhs.value();
+  }
+#else
+  /// Define an ordering for error_condition objects.
+  /// @relates error_condition
+  inline bool
+  operator<(const error_condition& __lhs,
+	    const error_condition& __rhs) noexcept
+  {
+    return (__lhs.category() < __rhs.category()
+	    || (__lhs.category() == __rhs.category()
+		&& __lhs.value() < __rhs.value()));
+  }
+
+  /// @relates error_condition
+  inline bool
+  operator==(const error_condition& __lhs, const error_code& __rhs) noexcept
+  {
+    return (__rhs.category().equivalent(__rhs.value(), __lhs)
+	    || __lhs.category().equivalent(__rhs, __lhs.value()));
+  }
+
+  /// @relates error_code
+  inline bool
+  operator!=(const error_code& __lhs, const error_code& __rhs) noexcept
+  { return !(__lhs == __rhs); }
+
+  /// @relates error_code
+  inline bool
+  operator!=(const error_code& __lhs, const error_condition& __rhs) noexcept
+  { return !(__lhs == __rhs); }
+
+  /// @relates error_condition
+  inline bool
+  operator!=(const error_condition& __lhs, const error_code& __rhs) noexcept
+  { return !(__lhs == __rhs); }
+
+  /// @relates error_condition
+  inline bool
+  operator!=(const error_condition& __lhs,
+	     const error_condition& __rhs) noexcept
+  { return !(__lhs == __rhs); }
+#endif // three_way_comparison
+  /// @}
+
+  /**
+   * @brief An exception type that includes an `error_code` value.
+   *
+   * Typically used to report errors from the operating system and other
+   * low-level APIs.
+   *
+   * @since C++11
+   * @ingroup exceptions
+   */
+  class system_error : public std::runtime_error
+  {
+  private:
+    error_code 	_M_code;
+
+  public:
+    system_error(error_code __ec = error_code())
+    : runtime_error(__ec.message()), _M_code(__ec) { }
+
+    system_error(error_code __ec, const string& __what)
+    : runtime_error(__what + ": " + __ec.message()), _M_code(__ec) { }
+
+    system_error(error_code __ec, const char* __what)
+    : runtime_error(__what + (": " + __ec.message())), _M_code(__ec) { }
+
+    system_error(int __v, const error_category& __ecat, const char* __what)
+    : system_error(error_code(__v, __ecat), __what) { }
+
+    system_error(int __v, const error_category& __ecat)
+    : runtime_error(error_code(__v, __ecat).message()),
+      _M_code(__v, __ecat) { }
+
+    system_error(int __v, const error_category& __ecat, const string& __what)
+    : runtime_error(__what + ": " + error_code(__v, __ecat).message()),
+      _M_code(__v, __ecat) { }
+
+#if __cplusplus >= 201103L
+    system_error (const system_error &) = default;
+    system_error &operator= (const system_error &) = default;
+#endif
+
+    virtual ~system_error() noexcept;
+
+    const error_code&
+    code() const noexcept { return _M_code; }
+  };
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#include <bits/functional_hash.h>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+#ifndef _GLIBCXX_COMPATIBILITY_CXX0X
+  // DR 1182.
+  /// std::hash specialization for error_code.
+  /// @relates error_code
+  template<>
+    struct hash<error_code>
+    : public __hash_base<size_t, error_code>
+    {
+      size_t
+      operator()(const error_code& __e) const noexcept
+      {
+	const size_t __tmp = std::_Hash_impl::hash(__e.value());
+	return std::_Hash_impl::__hash_combine(&__e.category(), __tmp);
+      }
+    };
+#endif // _GLIBCXX_COMPATIBILITY_CXX0X
+
+#if __cplusplus >= 201703L
+  // DR 2686.
+  /// std::hash specialization for error_condition.
+  /// @relates error_condition
+  template<>
+    struct hash<error_condition>
+    : public __hash_base<size_t, error_condition>
+    {
+      size_t
+      operator()(const error_condition& __e) const noexcept
+      {
+	const size_t __tmp = std::_Hash_impl::hash(__e.value());
+	return std::_Hash_impl::__hash_combine(&__e.category(), __tmp);
+      }
+    };
+#endif
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif // C++11
+
+#endif // _GLIBCXX_SYSTEM_ERROR
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@thread b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@thread
new file mode 100644
index 0000000000000000000000000000000000000000..92b24268ffe8eb226741a923b4c1844c5f4b2d39
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@thread
@@ -0,0 +1,265 @@
+// <thread> -*- C++ -*-
+
+// Copyright (C) 2008-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file include/thread
+ *  This is a Standard C++ Library header.
+ */
+
+#ifndef _GLIBCXX_THREAD
+#define _GLIBCXX_THREAD 1
+
+#pragma GCC system_header
+
+#if __cplusplus < 201103L
+# include <bits/c++0x_warning.h>
+#else
+
+#if __cplusplus > 201703L
+# include <compare>	// std::strong_ordering
+# include <stop_token>	// std::stop_source, std::stop_token, std::nostopstate
+#endif
+
+#include <bits/std_thread.h> // std::thread, get_id, yield
+#include <bits/this_thread_sleep.h> // std::this_thread::sleep_for, sleep_until
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /**
+   * @defgroup threads Threads
+   * @ingroup concurrency
+   *
+   * Classes for thread support.
+   * @{
+   */
+
+  // std::thread is defined in <bits/std_thread.h>
+
+#if __cpp_lib_three_way_comparison
+  inline strong_ordering
+  operator<=>(thread::id __x, thread::id __y) noexcept
+  { return __x._M_thread <=> __y._M_thread; }
+#else
+  inline bool
+  operator!=(thread::id __x, thread::id __y) noexcept
+  { return !(__x == __y); }
+
+  inline bool
+  operator<(thread::id __x, thread::id __y) noexcept
+  {
+    // Pthreads doesn't define any way to do this, so we just have to
+    // assume native_handle_type is LessThanComparable.
+    return __x._M_thread < __y._M_thread;
+  }
+
+  inline bool
+  operator<=(thread::id __x, thread::id __y) noexcept
+  { return !(__y < __x); }
+
+  inline bool
+  operator>(thread::id __x, thread::id __y) noexcept
+  { return __y < __x; }
+
+  inline bool
+  operator>=(thread::id __x, thread::id __y) noexcept
+  { return !(__x < __y); }
+#endif // __cpp_lib_three_way_comparison
+
+  template<class _CharT, class _Traits>
+    inline basic_ostream<_CharT, _Traits>&
+    operator<<(basic_ostream<_CharT, _Traits>& __out, thread::id __id)
+    {
+      if (__id == thread::id())
+	return __out << "thread::id of a non-executing thread";
+      else
+	return __out << __id._M_thread;
+    }
+
+#ifdef __cpp_lib_jthread
+
+#ifndef __STRICT_ANSI__
+    template<typename _Callable, typename... _Args>
+      constexpr bool __pmf_expects_stop_token = false;
+
+    template<typename _Callable, typename _Obj, typename... _Args>
+      constexpr bool __pmf_expects_stop_token<_Callable, _Obj, _Args...>
+	= __and_<is_member_function_pointer<remove_reference_t<_Callable>>,
+		 is_invocable<_Callable, _Obj, stop_token, _Args...>>::value;
+#endif
+
+  /// A thread that can be requested to stop and automatically joined.
+  class jthread
+  {
+  public:
+    using id = thread::id;
+    using native_handle_type = thread::native_handle_type;
+
+    jthread() noexcept
+    : _M_stop_source{nostopstate}
+    { }
+
+    template<typename _Callable, typename... _Args,
+	     typename = enable_if_t<!is_same_v<remove_cvref_t<_Callable>,
+					       jthread>>>
+      explicit
+      jthread(_Callable&& __f, _Args&&... __args)
+      : _M_thread{_S_create(_M_stop_source, std::forward<_Callable>(__f),
+			    std::forward<_Args>(__args)...)}
+      { }
+
+    jthread(const jthread&) = delete;
+    jthread(jthread&&) noexcept = default;
+
+    ~jthread()
+    {
+      if (joinable())
+        {
+          request_stop();
+          join();
+        }
+    }
+
+    jthread&
+    operator=(const jthread&) = delete;
+
+    jthread&
+    operator=(jthread&& __other) noexcept
+    {
+      std::jthread(std::move(__other)).swap(*this);
+      return *this;
+    }
+
+    void
+    swap(jthread& __other) noexcept
+    {
+      std::swap(_M_stop_source, __other._M_stop_source);
+      std::swap(_M_thread, __other._M_thread);
+    }
+
+    [[nodiscard]] bool
+    joinable() const noexcept
+    {
+      return _M_thread.joinable();
+    }
+
+    void
+    join()
+    {
+      _M_thread.join();
+    }
+
+    void
+    detach()
+    {
+      _M_thread.detach();
+    }
+
+    [[nodiscard]] id
+    get_id() const noexcept
+    {
+      return _M_thread.get_id();
+    }
+
+    [[nodiscard]] native_handle_type
+    native_handle()
+    {
+      return _M_thread.native_handle();
+    }
+
+    [[nodiscard]] static unsigned
+    hardware_concurrency() noexcept
+    {
+      return thread::hardware_concurrency();
+    }
+
+    [[nodiscard]] stop_source
+    get_stop_source() noexcept
+    {
+      return _M_stop_source;
+    }
+
+    [[nodiscard]] stop_token
+    get_stop_token() const noexcept
+    {
+      return _M_stop_source.get_token();
+    }
+
+    bool request_stop() noexcept
+    {
+      return _M_stop_source.request_stop();
+    }
+
+    friend void swap(jthread& __lhs, jthread& __rhs) noexcept
+    {
+      __lhs.swap(__rhs);
+    }
+
+  private:
+    template<typename _Callable, typename... _Args>
+      static thread
+      _S_create(stop_source& __ssrc, _Callable&& __f, _Args&&... __args)
+      {
+#ifndef __STRICT_ANSI__
+	if constexpr (__pmf_expects_stop_token<_Callable, _Args...>)
+	  return _S_create_pmf(__ssrc, __f, std::forward<_Args>(__args)...);
+	else
+#endif
+	if constexpr(is_invocable_v<decay_t<_Callable>, stop_token,
+				    decay_t<_Args>...>)
+	  return thread{std::forward<_Callable>(__f), __ssrc.get_token(),
+			std::forward<_Args>(__args)...};
+	else
+	  {
+	    static_assert(is_invocable_v<decay_t<_Callable>,
+					 decay_t<_Args>...>,
+			  "std::jthread arguments must be invocable after"
+			  " conversion to rvalues");
+	    return thread{std::forward<_Callable>(__f),
+			  std::forward<_Args>(__args)...};
+	  }
+      }
+
+#ifndef __STRICT_ANSI__
+    template<typename _Callable, typename _Obj, typename... _Args>
+      static thread
+      _S_create_pmf(stop_source& __ssrc, _Callable __f, _Obj&& __obj,
+		    _Args&&... __args)
+      {
+	return thread{__f, std::forward<_Obj>(__obj), __ssrc.get_token(),
+		      std::forward<_Args>(__args)...};
+      }
+#endif
+
+    stop_source _M_stop_source;
+    thread _M_thread;
+  };
+#endif // __cpp_lib_jthread
+
+  /// @} group threads
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+#endif // C++11
+#endif // _GLIBCXX_THREAD
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@thread.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@thread.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@tuple b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@tuple
new file mode 100644
index 0000000000000000000000000000000000000000..6d0060a191c6da3631477e5ca43e8c16bf62f9e7
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@tuple
@@ -0,0 +1,1893 @@
+// <tuple> -*- C++ -*-
+
+// Copyright (C) 2007-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file include/tuple
+ *  This is a Standard C++ Library header.
+ */
+
+#ifndef _GLIBCXX_TUPLE
+#define _GLIBCXX_TUPLE 1
+
+#pragma GCC system_header
+
+#if __cplusplus < 201103L
+# include <bits/c++0x_warning.h>
+#else
+
+#include <bits/stl_pair.h>		// for std::pair
+#include <bits/uses_allocator.h>	// for std::allocator_arg_t
+#include <bits/utility.h>		// for std::get, std::tuple_size etc.
+#include <bits/invoke.h>		// for std::__invoke
+#if __cplusplus > 201703L
+# include <compare>
+# define __cpp_lib_constexpr_tuple 201811L
+#endif
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /**
+   *  @addtogroup utilities
+   *  @{
+   */
+
+  template<typename... _Elements>
+    class tuple;
+
+  template<typename _Tp>
+    struct __is_empty_non_tuple : is_empty<_Tp> { };
+
+  // Using EBO for elements that are tuples causes ambiguous base errors.
+  template<typename _El0, typename... _El>
+    struct __is_empty_non_tuple<tuple<_El0, _El...>> : false_type { };
+
+  // Use the Empty Base-class Optimization for empty, non-final types.
+  template<typename _Tp>
+    using __empty_not_final
+    = __conditional_t<__is_final(_Tp), false_type,
+		      __is_empty_non_tuple<_Tp>>;
+
+  template<size_t _Idx, typename _Head,
+	   bool = __empty_not_final<_Head>::value>
+    struct _Head_base;
+
+#if __has_cpp_attribute(__no_unique_address__)
+  template<size_t _Idx, typename _Head>
+    struct _Head_base<_Idx, _Head, true>
+    {
+      constexpr _Head_base()
+      : _M_head_impl() { }
+
+      constexpr _Head_base(const _Head& __h)
+      : _M_head_impl(__h) { }
+
+      constexpr _Head_base(const _Head_base&) = default;
+      constexpr _Head_base(_Head_base&&) = default;
+
+      template<typename _UHead>
+	constexpr _Head_base(_UHead&& __h)
+	: _M_head_impl(std::forward<_UHead>(__h)) { }
+
+      _GLIBCXX20_CONSTEXPR
+      _Head_base(allocator_arg_t, __uses_alloc0)
+      : _M_head_impl() { }
+
+      template<typename _Alloc>
+	_GLIBCXX20_CONSTEXPR
+	_Head_base(allocator_arg_t, __uses_alloc1<_Alloc> __a)
+	: _M_head_impl(allocator_arg, *__a._M_a) { }
+
+      template<typename _Alloc>
+	_GLIBCXX20_CONSTEXPR
+	_Head_base(allocator_arg_t, __uses_alloc2<_Alloc> __a)
+	: _M_head_impl(*__a._M_a) { }
+
+      template<typename _UHead>
+	_GLIBCXX20_CONSTEXPR
+	_Head_base(__uses_alloc0, _UHead&& __uhead)
+	: _M_head_impl(std::forward<_UHead>(__uhead)) { }
+
+      template<typename _Alloc, typename _UHead>
+	_GLIBCXX20_CONSTEXPR
+	_Head_base(__uses_alloc1<_Alloc> __a, _UHead&& __uhead)
+	: _M_head_impl(allocator_arg, *__a._M_a, std::forward<_UHead>(__uhead))
+	{ }
+
+      template<typename _Alloc, typename _UHead>
+	_GLIBCXX20_CONSTEXPR
+	_Head_base(__uses_alloc2<_Alloc> __a, _UHead&& __uhead)
+	: _M_head_impl(std::forward<_UHead>(__uhead), *__a._M_a) { }
+
+      static constexpr _Head&
+      _M_head(_Head_base& __b) noexcept { return __b._M_head_impl; }
+
+      static constexpr const _Head&
+      _M_head(const _Head_base& __b) noexcept { return __b._M_head_impl; }
+
+      [[__no_unique_address__]] _Head _M_head_impl;
+    };
+#else
+  template<size_t _Idx, typename _Head>
+    struct _Head_base<_Idx, _Head, true>
+    : public _Head
+    {
+      constexpr _Head_base()
+      : _Head() { }
+
+      constexpr _Head_base(const _Head& __h)
+      : _Head(__h) { }
+
+      constexpr _Head_base(const _Head_base&) = default;
+      constexpr _Head_base(_Head_base&&) = default;
+
+      template<typename _UHead>
+        constexpr _Head_base(_UHead&& __h)
+	: _Head(std::forward<_UHead>(__h)) { }
+
+      _GLIBCXX20_CONSTEXPR
+      _Head_base(allocator_arg_t, __uses_alloc0)
+      : _Head() { }
+
+      template<typename _Alloc>
+	_GLIBCXX20_CONSTEXPR
+	_Head_base(allocator_arg_t, __uses_alloc1<_Alloc> __a)
+	: _Head(allocator_arg, *__a._M_a) { }
+
+      template<typename _Alloc>
+	_GLIBCXX20_CONSTEXPR
+	_Head_base(allocator_arg_t, __uses_alloc2<_Alloc> __a)
+	: _Head(*__a._M_a) { }
+
+      template<typename _UHead>
+	_GLIBCXX20_CONSTEXPR
+	_Head_base(__uses_alloc0, _UHead&& __uhead)
+	: _Head(std::forward<_UHead>(__uhead)) { }
+
+      template<typename _Alloc, typename _UHead>
+	_GLIBCXX20_CONSTEXPR
+	_Head_base(__uses_alloc1<_Alloc> __a, _UHead&& __uhead)
+	: _Head(allocator_arg, *__a._M_a, std::forward<_UHead>(__uhead)) { }
+
+      template<typename _Alloc, typename _UHead>
+	_GLIBCXX20_CONSTEXPR
+	_Head_base(__uses_alloc2<_Alloc> __a, _UHead&& __uhead)
+	: _Head(std::forward<_UHead>(__uhead), *__a._M_a) { }
+
+      static constexpr _Head&
+      _M_head(_Head_base& __b) noexcept { return __b; }
+
+      static constexpr const _Head&
+      _M_head(const _Head_base& __b) noexcept { return __b; }
+    };
+#endif
+
+  template<size_t _Idx, typename _Head>
+    struct _Head_base<_Idx, _Head, false>
+    {
+      constexpr _Head_base()
+      : _M_head_impl() { }
+
+      constexpr _Head_base(const _Head& __h)
+      : _M_head_impl(__h) { }
+
+      constexpr _Head_base(const _Head_base&) = default;
+      constexpr _Head_base(_Head_base&&) = default;
+
+      template<typename _UHead>
+        constexpr _Head_base(_UHead&& __h)
+	: _M_head_impl(std::forward<_UHead>(__h)) { }
+
+      _GLIBCXX20_CONSTEXPR
+      _Head_base(allocator_arg_t, __uses_alloc0)
+      : _M_head_impl() { }
+
+      template<typename _Alloc>
+	_GLIBCXX20_CONSTEXPR
+	_Head_base(allocator_arg_t, __uses_alloc1<_Alloc> __a)
+	: _M_head_impl(allocator_arg, *__a._M_a) { }
+
+      template<typename _Alloc>
+	_GLIBCXX20_CONSTEXPR
+	_Head_base(allocator_arg_t, __uses_alloc2<_Alloc> __a)
+	: _M_head_impl(*__a._M_a) { }
+
+      template<typename _UHead>
+	_GLIBCXX20_CONSTEXPR
+	_Head_base(__uses_alloc0, _UHead&& __uhead)
+	: _M_head_impl(std::forward<_UHead>(__uhead)) { }
+
+      template<typename _Alloc, typename _UHead>
+	_GLIBCXX20_CONSTEXPR
+	_Head_base(__uses_alloc1<_Alloc> __a, _UHead&& __uhead)
+	: _M_head_impl(allocator_arg, *__a._M_a, std::forward<_UHead>(__uhead))
+	{ }
+
+      template<typename _Alloc, typename _UHead>
+	_GLIBCXX20_CONSTEXPR
+	_Head_base(__uses_alloc2<_Alloc> __a, _UHead&& __uhead)
+	: _M_head_impl(std::forward<_UHead>(__uhead), *__a._M_a) { }
+
+      static constexpr _Head&
+      _M_head(_Head_base& __b) noexcept { return __b._M_head_impl; }
+
+      static constexpr const _Head&
+      _M_head(const _Head_base& __b) noexcept { return __b._M_head_impl; }
+
+      _Head _M_head_impl;
+    };
+
+  /**
+   * Contains the actual implementation of the @c tuple template, stored
+   * as a recursive inheritance hierarchy from the first element (most
+   * derived class) to the last (least derived class). The @c Idx
+   * parameter gives the 0-based index of the element stored at this
+   * point in the hierarchy; we use it to implement a constant-time
+   * get() operation.
+   */
+  template<size_t _Idx, typename... _Elements>
+    struct _Tuple_impl;
+
+  /**
+   * Recursive tuple implementation. Here we store the @c Head element
+   * and derive from a @c Tuple_impl containing the remaining elements
+   * (which contains the @c Tail).
+   */
+  template<size_t _Idx, typename _Head, typename... _Tail>
+    struct _Tuple_impl<_Idx, _Head, _Tail...>
+    : public _Tuple_impl<_Idx + 1, _Tail...>,
+      private _Head_base<_Idx, _Head>
+    {
+      template<size_t, typename...> friend struct _Tuple_impl;
+
+      typedef _Tuple_impl<_Idx + 1, _Tail...> _Inherited;
+      typedef _Head_base<_Idx, _Head> _Base;
+
+      static constexpr _Head&
+      _M_head(_Tuple_impl& __t) noexcept { return _Base::_M_head(__t); }
+
+      static constexpr const _Head&
+      _M_head(const _Tuple_impl& __t) noexcept { return _Base::_M_head(__t); }
+
+      static constexpr _Inherited&
+      _M_tail(_Tuple_impl& __t) noexcept { return __t; }
+
+      static constexpr const _Inherited&
+      _M_tail(const _Tuple_impl& __t) noexcept { return __t; }
+
+      constexpr _Tuple_impl()
+      : _Inherited(), _Base() { }
+
+      explicit constexpr
+      _Tuple_impl(const _Head& __head, const _Tail&... __tail)
+      : _Inherited(__tail...), _Base(__head)
+      { }
+
+      template<typename _UHead, typename... _UTail,
+	       typename = __enable_if_t<sizeof...(_Tail) == sizeof...(_UTail)>>
+	explicit constexpr
+	_Tuple_impl(_UHead&& __head, _UTail&&... __tail)
+	: _Inherited(std::forward<_UTail>(__tail)...),
+	  _Base(std::forward<_UHead>(__head))
+	{ }
+
+      constexpr _Tuple_impl(const _Tuple_impl&) = default;
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 2729. Missing SFINAE on std::pair::operator=
+      _Tuple_impl& operator=(const _Tuple_impl&) = delete;
+
+      _Tuple_impl(_Tuple_impl&&) = default;
+
+      template<typename... _UElements>
+	constexpr
+	_Tuple_impl(const _Tuple_impl<_Idx, _UElements...>& __in)
+	: _Inherited(_Tuple_impl<_Idx, _UElements...>::_M_tail(__in)),
+	  _Base(_Tuple_impl<_Idx, _UElements...>::_M_head(__in))
+	{ }
+
+      template<typename _UHead, typename... _UTails>
+	constexpr
+	_Tuple_impl(_Tuple_impl<_Idx, _UHead, _UTails...>&& __in)
+	: _Inherited(std::move
+		     (_Tuple_impl<_Idx, _UHead, _UTails...>::_M_tail(__in))),
+	  _Base(std::forward<_UHead>
+		(_Tuple_impl<_Idx, _UHead, _UTails...>::_M_head(__in)))
+	{ }
+
+      template<typename _Alloc>
+	_GLIBCXX20_CONSTEXPR
+	_Tuple_impl(allocator_arg_t __tag, const _Alloc& __a)
+	: _Inherited(__tag, __a),
+	  _Base(__tag, __use_alloc<_Head>(__a))
+	{ }
+
+      template<typename _Alloc>
+	_GLIBCXX20_CONSTEXPR
+	_Tuple_impl(allocator_arg_t __tag, const _Alloc& __a,
+		    const _Head& __head, const _Tail&... __tail)
+	: _Inherited(__tag, __a, __tail...),
+	  _Base(__use_alloc<_Head, _Alloc, _Head>(__a), __head)
+	{ }
+
+      template<typename _Alloc, typename _UHead, typename... _UTail,
+	       typename = __enable_if_t<sizeof...(_Tail) == sizeof...(_UTail)>>
+	_GLIBCXX20_CONSTEXPR
+	_Tuple_impl(allocator_arg_t __tag, const _Alloc& __a,
+		    _UHead&& __head, _UTail&&... __tail)
+	: _Inherited(__tag, __a, std::forward<_UTail>(__tail)...),
+	  _Base(__use_alloc<_Head, _Alloc, _UHead>(__a),
+		std::forward<_UHead>(__head))
+	{ }
+
+      template<typename _Alloc>
+	_GLIBCXX20_CONSTEXPR
+	_Tuple_impl(allocator_arg_t __tag, const _Alloc& __a,
+		    const _Tuple_impl& __in)
+	: _Inherited(__tag, __a, _M_tail(__in)),
+	  _Base(__use_alloc<_Head, _Alloc, _Head>(__a), _M_head(__in))
+	{ }
+
+      template<typename _Alloc>
+	_GLIBCXX20_CONSTEXPR
+	_Tuple_impl(allocator_arg_t __tag, const _Alloc& __a,
+		    _Tuple_impl&& __in)
+	: _Inherited(__tag, __a, std::move(_M_tail(__in))),
+	  _Base(__use_alloc<_Head, _Alloc, _Head>(__a),
+		std::forward<_Head>(_M_head(__in)))
+	{ }
+
+      template<typename _Alloc, typename _UHead, typename... _UTails>
+	_GLIBCXX20_CONSTEXPR
+	_Tuple_impl(allocator_arg_t __tag, const _Alloc& __a,
+		    const _Tuple_impl<_Idx, _UHead, _UTails...>& __in)
+	: _Inherited(__tag, __a,
+		     _Tuple_impl<_Idx, _UHead, _UTails...>::_M_tail(__in)),
+	  _Base(__use_alloc<_Head, _Alloc, const _UHead&>(__a),
+		_Tuple_impl<_Idx, _UHead, _UTails...>::_M_head(__in))
+	{ }
+
+      template<typename _Alloc, typename _UHead, typename... _UTails>
+	_GLIBCXX20_CONSTEXPR
+	_Tuple_impl(allocator_arg_t __tag, const _Alloc& __a,
+		    _Tuple_impl<_Idx, _UHead, _UTails...>&& __in)
+	: _Inherited(__tag, __a, std::move
+		     (_Tuple_impl<_Idx, _UHead, _UTails...>::_M_tail(__in))),
+	  _Base(__use_alloc<_Head, _Alloc, _UHead>(__a),
+		std::forward<_UHead>
+		(_Tuple_impl<_Idx, _UHead, _UTails...>::_M_head(__in)))
+	{ }
+
+      template<typename... _UElements>
+	_GLIBCXX20_CONSTEXPR
+	void
+	_M_assign(const _Tuple_impl<_Idx, _UElements...>& __in)
+	{
+	  _M_head(*this) = _Tuple_impl<_Idx, _UElements...>::_M_head(__in);
+	  _M_tail(*this)._M_assign(
+	      _Tuple_impl<_Idx, _UElements...>::_M_tail(__in));
+	}
+
+      template<typename _UHead, typename... _UTails>
+	_GLIBCXX20_CONSTEXPR
+	void
+	_M_assign(_Tuple_impl<_Idx, _UHead, _UTails...>&& __in)
+	{
+	  _M_head(*this) = std::forward<_UHead>
+	    (_Tuple_impl<_Idx, _UHead, _UTails...>::_M_head(__in));
+	  _M_tail(*this)._M_assign(
+	      std::move(_Tuple_impl<_Idx, _UHead, _UTails...>::_M_tail(__in)));
+	}
+
+    protected:
+      _GLIBCXX20_CONSTEXPR
+      void
+      _M_swap(_Tuple_impl& __in)
+      {
+	using std::swap;
+	swap(_M_head(*this), _M_head(__in));
+	_Inherited::_M_swap(_M_tail(__in));
+      }
+    };
+
+  // Basis case of inheritance recursion.
+  template<size_t _Idx, typename _Head>
+    struct _Tuple_impl<_Idx, _Head>
+    : private _Head_base<_Idx, _Head>
+    {
+      template<size_t, typename...> friend struct _Tuple_impl;
+
+      typedef _Head_base<_Idx, _Head> _Base;
+
+      static constexpr _Head&
+      _M_head(_Tuple_impl& __t) noexcept { return _Base::_M_head(__t); }
+
+      static constexpr const _Head&
+      _M_head(const _Tuple_impl& __t) noexcept { return _Base::_M_head(__t); }
+
+      constexpr
+      _Tuple_impl()
+      : _Base() { }
+
+      explicit constexpr
+      _Tuple_impl(const _Head& __head)
+      : _Base(__head)
+      { }
+
+      template<typename _UHead>
+	explicit constexpr
+	_Tuple_impl(_UHead&& __head)
+	: _Base(std::forward<_UHead>(__head))
+	{ }
+
+      constexpr _Tuple_impl(const _Tuple_impl&) = default;
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 2729. Missing SFINAE on std::pair::operator=
+      _Tuple_impl& operator=(const _Tuple_impl&) = delete;
+
+#if _GLIBCXX_INLINE_VERSION
+      _Tuple_impl(_Tuple_impl&&) = default;
+#else
+      constexpr
+      _Tuple_impl(_Tuple_impl&& __in)
+      noexcept(is_nothrow_move_constructible<_Head>::value)
+      : _Base(static_cast<_Base&&>(__in))
+      { }
+#endif
+
+      template<typename _UHead>
+	constexpr
+	_Tuple_impl(const _Tuple_impl<_Idx, _UHead>& __in)
+	: _Base(_Tuple_impl<_Idx, _UHead>::_M_head(__in))
+	{ }
+
+      template<typename _UHead>
+	constexpr
+	_Tuple_impl(_Tuple_impl<_Idx, _UHead>&& __in)
+	: _Base(std::forward<_UHead>(_Tuple_impl<_Idx, _UHead>::_M_head(__in)))
+	{ }
+
+      template<typename _Alloc>
+	_GLIBCXX20_CONSTEXPR
+	_Tuple_impl(allocator_arg_t __tag, const _Alloc& __a)
+	: _Base(__tag, __use_alloc<_Head>(__a))
+	{ }
+
+      template<typename _Alloc>
+	_GLIBCXX20_CONSTEXPR
+	_Tuple_impl(allocator_arg_t __tag, const _Alloc& __a,
+		    const _Head& __head)
+	: _Base(__use_alloc<_Head, _Alloc, const _Head&>(__a), __head)
+	{ }
+
+      template<typename _Alloc, typename _UHead>
+	_GLIBCXX20_CONSTEXPR
+	_Tuple_impl(allocator_arg_t __tag, const _Alloc& __a,
+		    _UHead&& __head)
+	: _Base(__use_alloc<_Head, _Alloc, _UHead>(__a),
+		std::forward<_UHead>(__head))
+	{ }
+
+      template<typename _Alloc>
+	_GLIBCXX20_CONSTEXPR
+	_Tuple_impl(allocator_arg_t __tag, const _Alloc& __a,
+		    const _Tuple_impl& __in)
+	: _Base(__use_alloc<_Head, _Alloc, const _Head&>(__a), _M_head(__in))
+	{ }
+
+      template<typename _Alloc>
+	_GLIBCXX20_CONSTEXPR
+	_Tuple_impl(allocator_arg_t __tag, const _Alloc& __a,
+		    _Tuple_impl&& __in)
+	: _Base(__use_alloc<_Head, _Alloc, _Head>(__a),
+		std::forward<_Head>(_M_head(__in)))
+	{ }
+
+      template<typename _Alloc, typename _UHead>
+	_GLIBCXX20_CONSTEXPR
+	_Tuple_impl(allocator_arg_t __tag, const _Alloc& __a,
+		    const _Tuple_impl<_Idx, _UHead>& __in)
+	: _Base(__use_alloc<_Head, _Alloc, const _UHead&>(__a),
+		_Tuple_impl<_Idx, _UHead>::_M_head(__in))
+	{ }
+
+      template<typename _Alloc, typename _UHead>
+	_GLIBCXX20_CONSTEXPR
+	_Tuple_impl(allocator_arg_t __tag, const _Alloc& __a,
+		    _Tuple_impl<_Idx, _UHead>&& __in)
+	: _Base(__use_alloc<_Head, _Alloc, _UHead>(__a),
+		std::forward<_UHead>(_Tuple_impl<_Idx, _UHead>::_M_head(__in)))
+	{ }
+
+      template<typename _UHead>
+	_GLIBCXX20_CONSTEXPR
+	void
+	_M_assign(const _Tuple_impl<_Idx, _UHead>& __in)
+	{
+	  _M_head(*this) = _Tuple_impl<_Idx, _UHead>::_M_head(__in);
+	}
+
+      template<typename _UHead>
+	_GLIBCXX20_CONSTEXPR
+	void
+	_M_assign(_Tuple_impl<_Idx, _UHead>&& __in)
+	{
+	  _M_head(*this)
+	    = std::forward<_UHead>(_Tuple_impl<_Idx, _UHead>::_M_head(__in));
+	}
+
+    protected:
+      _GLIBCXX20_CONSTEXPR
+      void
+      _M_swap(_Tuple_impl& __in)
+      {
+	using std::swap;
+	swap(_M_head(*this), _M_head(__in));
+      }
+    };
+
+  // Concept utility functions, reused in conditionally-explicit
+  // constructors.
+  template<bool, typename... _Types>
+    struct _TupleConstraints
+    {
+      // Constraint for a non-explicit constructor.
+      // True iff each Ti in _Types... can be constructed from Ui in _UTypes...
+      // and every Ui is implicitly convertible to Ti.
+      template<typename... _UTypes>
+	static constexpr bool __is_implicitly_constructible()
+	{
+	  return __and_<is_constructible<_Types, _UTypes>...,
+			is_convertible<_UTypes, _Types>...
+			>::value;
+	}
+
+      // Constraint for a non-explicit constructor.
+      // True iff each Ti in _Types... can be constructed from Ui in _UTypes...
+      // but not every Ui is implicitly convertible to Ti.
+      template<typename... _UTypes>
+	static constexpr bool __is_explicitly_constructible()
+	{
+	  return __and_<is_constructible<_Types, _UTypes>...,
+			__not_<__and_<is_convertible<_UTypes, _Types>...>>
+			>::value;
+	}
+
+      static constexpr bool __is_implicitly_default_constructible()
+      {
+	return __and_<std::__is_implicitly_default_constructible<_Types>...
+		      >::value;
+      }
+
+      static constexpr bool __is_explicitly_default_constructible()
+      {
+	return __and_<is_default_constructible<_Types>...,
+		      __not_<__and_<
+			std::__is_implicitly_default_constructible<_Types>...>
+		      >>::value;
+      }
+    };
+
+  // Partial specialization used when a required precondition isn't met,
+  // e.g. when sizeof...(_Types) != sizeof...(_UTypes).
+  template<typename... _Types>
+    struct _TupleConstraints<false, _Types...>
+    {
+      template<typename... _UTypes>
+	static constexpr bool __is_implicitly_constructible()
+	{ return false; }
+
+      template<typename... _UTypes>
+	static constexpr bool __is_explicitly_constructible()
+	{ return false; }
+    };
+
+  /// Primary class template, tuple
+  template<typename... _Elements>
+    class tuple : public _Tuple_impl<0, _Elements...>
+    {
+      typedef _Tuple_impl<0, _Elements...> _Inherited;
+
+      template<bool _Cond>
+	using _TCC = _TupleConstraints<_Cond, _Elements...>;
+
+      // Constraint for non-explicit default constructor
+      template<bool _Dummy>
+	using _ImplicitDefaultCtor = __enable_if_t<
+	  _TCC<_Dummy>::__is_implicitly_default_constructible(),
+	  bool>;
+
+      // Constraint for explicit default constructor
+      template<bool _Dummy>
+	using _ExplicitDefaultCtor = __enable_if_t<
+	  _TCC<_Dummy>::__is_explicitly_default_constructible(),
+	  bool>;
+
+      // Constraint for non-explicit constructors
+      template<bool _Cond, typename... _Args>
+	using _ImplicitCtor = __enable_if_t<
+	  _TCC<_Cond>::template __is_implicitly_constructible<_Args...>(),
+	  bool>;
+
+      // Constraint for non-explicit constructors
+      template<bool _Cond, typename... _Args>
+	using _ExplicitCtor = __enable_if_t<
+	  _TCC<_Cond>::template __is_explicitly_constructible<_Args...>(),
+	  bool>;
+
+      template<typename... _UElements>
+	static constexpr
+	__enable_if_t<sizeof...(_UElements) == sizeof...(_Elements), bool>
+	__assignable()
+	{ return __and_<is_assignable<_Elements&, _UElements>...>::value; }
+
+      // Condition for noexcept-specifier of an assignment operator.
+      template<typename... _UElements>
+	static constexpr bool __nothrow_assignable()
+	{
+	  return
+	    __and_<is_nothrow_assignable<_Elements&, _UElements>...>::value;
+	}
+
+      // Condition for noexcept-specifier of a constructor.
+      template<typename... _UElements>
+	static constexpr bool __nothrow_constructible()
+	{
+	  return
+	    __and_<is_nothrow_constructible<_Elements, _UElements>...>::value;
+	}
+
+      // Constraint for tuple(_UTypes&&...) where sizeof...(_UTypes) == 1.
+      template<typename _Up>
+	static constexpr bool __valid_args()
+	{
+	  return sizeof...(_Elements) == 1
+	    && !is_same<tuple, __remove_cvref_t<_Up>>::value;
+	}
+
+      // Constraint for tuple(_UTypes&&...) where sizeof...(_UTypes) > 1.
+      template<typename, typename, typename... _Tail>
+	static constexpr bool __valid_args()
+	{ return (sizeof...(_Tail) + 2) == sizeof...(_Elements); }
+
+      /* Constraint for constructors with a tuple<UTypes...> parameter ensures
+       * that the constructor is only viable when it would not interfere with
+       * tuple(UTypes&&...) or tuple(const tuple&) or tuple(tuple&&).
+       * Such constructors are only viable if:
+       * either sizeof...(Types) != 1,
+       * or (when Types... expands to T and UTypes... expands to U)
+       * is_convertible_v<TUPLE, T>, is_constructible_v<T, TUPLE>,
+       * and is_same_v<T, U> are all false.
+       */
+      template<typename _Tuple, typename = tuple,
+	       typename = __remove_cvref_t<_Tuple>>
+	struct _UseOtherCtor
+	: false_type
+	{ };
+      // If TUPLE is convertible to the single element in *this,
+      // then TUPLE should match tuple(UTypes&&...) instead.
+      template<typename _Tuple, typename _Tp, typename _Up>
+	struct _UseOtherCtor<_Tuple, tuple<_Tp>, tuple<_Up>>
+	: __or_<is_convertible<_Tuple, _Tp>, is_constructible<_Tp, _Tuple>>
+	{ };
+      // If TUPLE and *this each have a single element of the same type,
+      // then TUPLE should match a copy/move constructor instead.
+      template<typename _Tuple, typename _Tp>
+	struct _UseOtherCtor<_Tuple, tuple<_Tp>, tuple<_Tp>>
+	: true_type
+	{ };
+
+      // Return true iff sizeof...(Types) == 1 && tuple_size_v<TUPLE> == 1
+      // and the single element in Types can be initialized from TUPLE,
+      // or is the same type as tuple_element_t<0, TUPLE>.
+      template<typename _Tuple>
+	static constexpr bool __use_other_ctor()
+	{ return _UseOtherCtor<_Tuple>::value; }
+
+    public:
+      template<typename _Dummy = void,
+	       _ImplicitDefaultCtor<is_void<_Dummy>::value> = true>
+	constexpr
+	tuple()
+	noexcept(__and_<is_nothrow_default_constructible<_Elements>...>::value)
+	: _Inherited() { }
+
+      template<typename _Dummy = void,
+	       _ExplicitDefaultCtor<is_void<_Dummy>::value> = false>
+	explicit constexpr
+	tuple()
+	noexcept(__and_<is_nothrow_default_constructible<_Elements>...>::value)
+	: _Inherited() { }
+
+      template<bool _NotEmpty = (sizeof...(_Elements) >= 1),
+	       _ImplicitCtor<_NotEmpty, const _Elements&...> = true>
+	constexpr
+	tuple(const _Elements&... __elements)
+	noexcept(__nothrow_constructible<const _Elements&...>())
+	: _Inherited(__elements...) { }
+
+      template<bool _NotEmpty = (sizeof...(_Elements) >= 1),
+	       _ExplicitCtor<_NotEmpty, const _Elements&...> = false>
+	explicit constexpr
+	tuple(const _Elements&... __elements)
+	noexcept(__nothrow_constructible<const _Elements&...>())
+	: _Inherited(__elements...) { }
+
+      template<typename... _UElements,
+	       bool _Valid = __valid_args<_UElements...>(),
+	       _ImplicitCtor<_Valid, _UElements...> = true>
+	constexpr
+	tuple(_UElements&&... __elements)
+	noexcept(__nothrow_constructible<_UElements...>())
+	: _Inherited(std::forward<_UElements>(__elements)...) { }
+
+      template<typename... _UElements,
+	       bool _Valid = __valid_args<_UElements...>(),
+	       _ExplicitCtor<_Valid, _UElements...> = false>
+	explicit constexpr
+	tuple(_UElements&&... __elements)
+	noexcept(__nothrow_constructible<_UElements...>())
+	: _Inherited(std::forward<_UElements>(__elements)...) {	}
+
+      constexpr tuple(const tuple&) = default;
+
+      constexpr tuple(tuple&&) = default;
+
+      template<typename... _UElements,
+	       bool _Valid = (sizeof...(_Elements) == sizeof...(_UElements))
+			   && !__use_other_ctor<const tuple<_UElements...>&>(),
+	       _ImplicitCtor<_Valid, const _UElements&...> = true>
+	constexpr
+	tuple(const tuple<_UElements...>& __in)
+	noexcept(__nothrow_constructible<const _UElements&...>())
+	: _Inherited(static_cast<const _Tuple_impl<0, _UElements...>&>(__in))
+	{ }
+
+      template<typename... _UElements,
+	       bool _Valid = (sizeof...(_Elements) == sizeof...(_UElements))
+			   && !__use_other_ctor<const tuple<_UElements...>&>(),
+	       _ExplicitCtor<_Valid, const _UElements&...> = false>
+	explicit constexpr
+	tuple(const tuple<_UElements...>& __in)
+	noexcept(__nothrow_constructible<const _UElements&...>())
+	: _Inherited(static_cast<const _Tuple_impl<0, _UElements...>&>(__in))
+	{ }
+
+      template<typename... _UElements,
+	       bool _Valid = (sizeof...(_Elements) == sizeof...(_UElements))
+			     && !__use_other_ctor<tuple<_UElements...>&&>(),
+	       _ImplicitCtor<_Valid, _UElements...> = true>
+	constexpr
+	tuple(tuple<_UElements...>&& __in)
+	noexcept(__nothrow_constructible<_UElements...>())
+	: _Inherited(static_cast<_Tuple_impl<0, _UElements...>&&>(__in)) { }
+
+      template<typename... _UElements,
+	       bool _Valid = (sizeof...(_Elements) == sizeof...(_UElements))
+			     && !__use_other_ctor<tuple<_UElements...>&&>(),
+	       _ExplicitCtor<_Valid, _UElements...> = false>
+	explicit constexpr
+	tuple(tuple<_UElements...>&& __in)
+	noexcept(__nothrow_constructible<_UElements...>())
+	: _Inherited(static_cast<_Tuple_impl<0, _UElements...>&&>(__in)) { }
+
+      // Allocator-extended constructors.
+
+      template<typename _Alloc,
+	       _ImplicitDefaultCtor<is_object<_Alloc>::value> = true>
+	_GLIBCXX20_CONSTEXPR
+	tuple(allocator_arg_t __tag, const _Alloc& __a)
+	: _Inherited(__tag, __a) { }
+
+      template<typename _Alloc, bool _NotEmpty = (sizeof...(_Elements) >= 1),
+	       _ImplicitCtor<_NotEmpty, const _Elements&...> = true>
+	_GLIBCXX20_CONSTEXPR
+	tuple(allocator_arg_t __tag, const _Alloc& __a,
+	      const _Elements&... __elements)
+	: _Inherited(__tag, __a, __elements...) { }
+
+      template<typename _Alloc, bool _NotEmpty = (sizeof...(_Elements) >= 1),
+	       _ExplicitCtor<_NotEmpty, const _Elements&...> = false>
+	_GLIBCXX20_CONSTEXPR
+	explicit
+	tuple(allocator_arg_t __tag, const _Alloc& __a,
+	      const _Elements&... __elements)
+	: _Inherited(__tag, __a, __elements...) { }
+
+      template<typename _Alloc, typename... _UElements,
+	       bool _Valid = __valid_args<_UElements...>(),
+	       _ImplicitCtor<_Valid, _UElements...> = true>
+	_GLIBCXX20_CONSTEXPR
+	tuple(allocator_arg_t __tag, const _Alloc& __a,
+	      _UElements&&... __elements)
+	: _Inherited(__tag, __a, std::forward<_UElements>(__elements)...)
+	{ }
+
+      template<typename _Alloc, typename... _UElements,
+		 bool _Valid = __valid_args<_UElements...>(),
+	       _ExplicitCtor<_Valid, _UElements...> = false>
+	_GLIBCXX20_CONSTEXPR
+	explicit
+	tuple(allocator_arg_t __tag, const _Alloc& __a,
+	      _UElements&&... __elements)
+	: _Inherited(__tag, __a, std::forward<_UElements>(__elements)...)
+	{ }
+
+      template<typename _Alloc>
+	_GLIBCXX20_CONSTEXPR
+	tuple(allocator_arg_t __tag, const _Alloc& __a, const tuple& __in)
+	: _Inherited(__tag, __a, static_cast<const _Inherited&>(__in)) { }
+
+      template<typename _Alloc>
+	_GLIBCXX20_CONSTEXPR
+	tuple(allocator_arg_t __tag, const _Alloc& __a, tuple&& __in)
+	: _Inherited(__tag, __a, static_cast<_Inherited&&>(__in)) { }
+
+      template<typename _Alloc, typename... _UElements,
+	       bool _Valid = (sizeof...(_Elements) == sizeof...(_UElements))
+			     && !__use_other_ctor<const tuple<_UElements...>&>(),
+	       _ImplicitCtor<_Valid, const _UElements&...> = true>
+	_GLIBCXX20_CONSTEXPR
+	tuple(allocator_arg_t __tag, const _Alloc& __a,
+	      const tuple<_UElements...>& __in)
+	: _Inherited(__tag, __a,
+	             static_cast<const _Tuple_impl<0, _UElements...>&>(__in))
+	{ }
+
+      template<typename _Alloc, typename... _UElements,
+	       bool _Valid = (sizeof...(_Elements) == sizeof...(_UElements))
+			     && !__use_other_ctor<const tuple<_UElements...>&>(),
+	       _ExplicitCtor<_Valid, const _UElements&...> = false>
+	_GLIBCXX20_CONSTEXPR
+	explicit
+	tuple(allocator_arg_t __tag, const _Alloc& __a,
+	      const tuple<_UElements...>& __in)
+	: _Inherited(__tag, __a,
+	             static_cast<const _Tuple_impl<0, _UElements...>&>(__in))
+	{ }
+
+      template<typename _Alloc, typename... _UElements,
+	       bool _Valid = (sizeof...(_Elements) == sizeof...(_UElements))
+			     && !__use_other_ctor<tuple<_UElements...>&&>(),
+	       _ImplicitCtor<_Valid, _UElements...> = true>
+	_GLIBCXX20_CONSTEXPR
+	tuple(allocator_arg_t __tag, const _Alloc& __a,
+	      tuple<_UElements...>&& __in)
+	: _Inherited(__tag, __a,
+	             static_cast<_Tuple_impl<0, _UElements...>&&>(__in))
+	{ }
+
+      template<typename _Alloc, typename... _UElements,
+	       bool _Valid = (sizeof...(_Elements) == sizeof...(_UElements))
+			     && !__use_other_ctor<tuple<_UElements...>&&>(),
+	       _ExplicitCtor<_Valid, _UElements...> = false>
+	_GLIBCXX20_CONSTEXPR
+	explicit
+	tuple(allocator_arg_t __tag, const _Alloc& __a,
+	      tuple<_UElements...>&& __in)
+	: _Inherited(__tag, __a,
+	             static_cast<_Tuple_impl<0, _UElements...>&&>(__in))
+	{ }
+
+      // tuple assignment
+
+      _GLIBCXX20_CONSTEXPR
+      tuple&
+      operator=(__conditional_t<__assignable<const _Elements&...>(),
+				const tuple&,
+				const __nonesuch&> __in)
+      noexcept(__nothrow_assignable<const _Elements&...>())
+      {
+	this->_M_assign(__in);
+	return *this;
+      }
+
+      _GLIBCXX20_CONSTEXPR
+      tuple&
+      operator=(__conditional_t<__assignable<_Elements...>(),
+				tuple&&,
+				__nonesuch&&> __in)
+      noexcept(__nothrow_assignable<_Elements...>())
+      {
+	this->_M_assign(std::move(__in));
+	return *this;
+      }
+
+      template<typename... _UElements>
+	_GLIBCXX20_CONSTEXPR
+	__enable_if_t<__assignable<const _UElements&...>(), tuple&>
+	operator=(const tuple<_UElements...>& __in)
+	noexcept(__nothrow_assignable<const _UElements&...>())
+	{
+	  this->_M_assign(__in);
+	  return *this;
+	}
+
+      template<typename... _UElements>
+	_GLIBCXX20_CONSTEXPR
+	__enable_if_t<__assignable<_UElements...>(), tuple&>
+	operator=(tuple<_UElements...>&& __in)
+	noexcept(__nothrow_assignable<_UElements...>())
+	{
+	  this->_M_assign(std::move(__in));
+	  return *this;
+	}
+
+      // tuple swap
+      _GLIBCXX20_CONSTEXPR
+      void
+      swap(tuple& __in)
+      noexcept(__and_<__is_nothrow_swappable<_Elements>...>::value)
+      { _Inherited::_M_swap(__in); }
+    };
+
+#if __cpp_deduction_guides >= 201606
+  template<typename... _UTypes>
+    tuple(_UTypes...) -> tuple<_UTypes...>;
+  template<typename _T1, typename _T2>
+    tuple(pair<_T1, _T2>) -> tuple<_T1, _T2>;
+  template<typename _Alloc, typename... _UTypes>
+    tuple(allocator_arg_t, _Alloc, _UTypes...) -> tuple<_UTypes...>;
+  template<typename _Alloc, typename _T1, typename _T2>
+    tuple(allocator_arg_t, _Alloc, pair<_T1, _T2>) -> tuple<_T1, _T2>;
+  template<typename _Alloc, typename... _UTypes>
+    tuple(allocator_arg_t, _Alloc, tuple<_UTypes...>) -> tuple<_UTypes...>;
+#endif
+
+  // Explicit specialization, zero-element tuple.
+  template<>
+    class tuple<>
+    {
+    public:
+      _GLIBCXX20_CONSTEXPR
+      void swap(tuple&) noexcept { /* no-op */ }
+      // We need the default since we're going to define no-op
+      // allocator constructors.
+      tuple() = default;
+      // No-op allocator constructors.
+      template<typename _Alloc>
+	_GLIBCXX20_CONSTEXPR
+	tuple(allocator_arg_t, const _Alloc&) noexcept { }
+      template<typename _Alloc>
+	_GLIBCXX20_CONSTEXPR
+	tuple(allocator_arg_t, const _Alloc&, const tuple&) noexcept { }
+    };
+
+  /// Partial specialization, 2-element tuple.
+  /// Includes construction and assignment from a pair.
+  template<typename _T1, typename _T2>
+    class tuple<_T1, _T2> : public _Tuple_impl<0, _T1, _T2>
+    {
+      typedef _Tuple_impl<0, _T1, _T2> _Inherited;
+
+      // Constraint for non-explicit default constructor
+      template<bool _Dummy, typename _U1, typename _U2>
+	using _ImplicitDefaultCtor = __enable_if_t<
+	  _TupleConstraints<_Dummy, _U1, _U2>::
+	    __is_implicitly_default_constructible(),
+	  bool>;
+
+      // Constraint for explicit default constructor
+      template<bool _Dummy, typename _U1, typename _U2>
+	using _ExplicitDefaultCtor = __enable_if_t<
+	  _TupleConstraints<_Dummy, _U1, _U2>::
+	    __is_explicitly_default_constructible(),
+	  bool>;
+
+      template<bool _Dummy>
+	using _TCC = _TupleConstraints<_Dummy, _T1, _T2>;
+
+      // Constraint for non-explicit constructors
+      template<bool _Cond, typename _U1, typename _U2>
+	using _ImplicitCtor = __enable_if_t<
+	  _TCC<_Cond>::template __is_implicitly_constructible<_U1, _U2>(),
+	  bool>;
+
+      // Constraint for non-explicit constructors
+      template<bool _Cond, typename _U1, typename _U2>
+	using _ExplicitCtor = __enable_if_t<
+	  _TCC<_Cond>::template __is_explicitly_constructible<_U1, _U2>(),
+	  bool>;
+
+      template<typename _U1, typename _U2>
+	static constexpr bool __assignable()
+	{
+	  return __and_<is_assignable<_T1&, _U1>,
+			is_assignable<_T2&, _U2>>::value;
+	}
+
+      template<typename _U1, typename _U2>
+	static constexpr bool __nothrow_assignable()
+	{
+	  return __and_<is_nothrow_assignable<_T1&, _U1>,
+			is_nothrow_assignable<_T2&, _U2>>::value;
+	}
+
+      template<typename _U1, typename _U2>
+	static constexpr bool __nothrow_constructible()
+	{
+	  return __and_<is_nothrow_constructible<_T1, _U1>,
+			    is_nothrow_constructible<_T2, _U2>>::value;
+	}
+
+      static constexpr bool __nothrow_default_constructible()
+      {
+	return __and_<is_nothrow_default_constructible<_T1>,
+		      is_nothrow_default_constructible<_T2>>::value;
+      }
+
+      template<typename _U1>
+	static constexpr bool __is_alloc_arg()
+	{ return is_same<__remove_cvref_t<_U1>, allocator_arg_t>::value; }
+
+    public:
+      template<bool _Dummy = true,
+	       _ImplicitDefaultCtor<_Dummy, _T1, _T2> = true>
+	constexpr
+	tuple()
+	noexcept(__nothrow_default_constructible())
+	: _Inherited() { }
+
+      template<bool _Dummy = true,
+	       _ExplicitDefaultCtor<_Dummy, _T1, _T2> = false>
+	explicit constexpr
+	tuple()
+	noexcept(__nothrow_default_constructible())
+	: _Inherited() { }
+
+      template<bool _Dummy = true,
+	       _ImplicitCtor<_Dummy, const _T1&, const _T2&> = true>
+	constexpr
+	tuple(const _T1& __a1, const _T2& __a2)
+	noexcept(__nothrow_constructible<const _T1&, const _T2&>())
+	: _Inherited(__a1, __a2) { }
+
+      template<bool _Dummy = true,
+	       _ExplicitCtor<_Dummy, const _T1&, const _T2&> = false>
+	explicit constexpr
+	tuple(const _T1& __a1, const _T2& __a2)
+	noexcept(__nothrow_constructible<const _T1&, const _T2&>())
+	: _Inherited(__a1, __a2) { }
+
+      template<typename _U1, typename _U2,
+	       _ImplicitCtor<!__is_alloc_arg<_U1>(), _U1, _U2> = true>
+	constexpr
+	tuple(_U1&& __a1, _U2&& __a2)
+	noexcept(__nothrow_constructible<_U1, _U2>())
+	: _Inherited(std::forward<_U1>(__a1), std::forward<_U2>(__a2)) { }
+
+      template<typename _U1, typename _U2,
+	       _ExplicitCtor<!__is_alloc_arg<_U1>(), _U1, _U2> = false>
+	explicit constexpr
+	tuple(_U1&& __a1, _U2&& __a2)
+	noexcept(__nothrow_constructible<_U1, _U2>())
+	: _Inherited(std::forward<_U1>(__a1), std::forward<_U2>(__a2)) { }
+
+      constexpr tuple(const tuple&) = default;
+
+      constexpr tuple(tuple&&) = default;
+
+      template<typename _U1, typename _U2,
+	       _ImplicitCtor<true, const _U1&, const _U2&> = true>
+	constexpr
+	tuple(const tuple<_U1, _U2>& __in)
+	noexcept(__nothrow_constructible<const _U1&, const _U2&>())
+	: _Inherited(static_cast<const _Tuple_impl<0, _U1, _U2>&>(__in)) { }
+
+      template<typename _U1, typename _U2,
+	       _ExplicitCtor<true, const _U1&, const _U2&> = false>
+	explicit constexpr
+	tuple(const tuple<_U1, _U2>& __in)
+	noexcept(__nothrow_constructible<const _U1&, const _U2&>())
+	: _Inherited(static_cast<const _Tuple_impl<0, _U1, _U2>&>(__in)) { }
+
+      template<typename _U1, typename _U2,
+	       _ImplicitCtor<true, _U1, _U2> = true>
+	constexpr
+	tuple(tuple<_U1, _U2>&& __in)
+	noexcept(__nothrow_constructible<_U1, _U2>())
+	: _Inherited(static_cast<_Tuple_impl<0, _U1, _U2>&&>(__in)) { }
+
+      template<typename _U1, typename _U2,
+	       _ExplicitCtor<true, _U1, _U2> = false>
+	explicit constexpr
+	tuple(tuple<_U1, _U2>&& __in)
+	noexcept(__nothrow_constructible<_U1, _U2>())
+	: _Inherited(static_cast<_Tuple_impl<0, _U1, _U2>&&>(__in)) { }
+
+      template<typename _U1, typename _U2,
+	       _ImplicitCtor<true, const _U1&, const _U2&> = true>
+	constexpr
+	tuple(const pair<_U1, _U2>& __in)
+	noexcept(__nothrow_constructible<const _U1&, const _U2&>())
+	: _Inherited(__in.first, __in.second) { }
+
+      template<typename _U1, typename _U2,
+	       _ExplicitCtor<true, const _U1&, const _U2&> = false>
+	explicit constexpr
+	tuple(const pair<_U1, _U2>& __in)
+	noexcept(__nothrow_constructible<const _U1&, const _U2&>())
+	: _Inherited(__in.first, __in.second) { }
+
+      template<typename _U1, typename _U2,
+	       _ImplicitCtor<true, _U1, _U2> = true>
+	constexpr
+	tuple(pair<_U1, _U2>&& __in)
+	noexcept(__nothrow_constructible<_U1, _U2>())
+	: _Inherited(std::forward<_U1>(__in.first),
+		     std::forward<_U2>(__in.second)) { }
+
+      template<typename _U1, typename _U2,
+	       _ExplicitCtor<true, _U1, _U2> = false>
+	explicit constexpr
+	tuple(pair<_U1, _U2>&& __in)
+	noexcept(__nothrow_constructible<_U1, _U2>())
+	: _Inherited(std::forward<_U1>(__in.first),
+		     std::forward<_U2>(__in.second)) { }
+
+      // Allocator-extended constructors.
+
+      template<typename _Alloc,
+	       _ImplicitDefaultCtor<is_object<_Alloc>::value, _T1, _T2> = true>
+	_GLIBCXX20_CONSTEXPR
+	tuple(allocator_arg_t __tag, const _Alloc& __a)
+	: _Inherited(__tag, __a) { }
+
+      template<typename _Alloc, bool _Dummy = true,
+	       _ImplicitCtor<_Dummy, const _T1&, const _T2&> = true>
+	_GLIBCXX20_CONSTEXPR
+	tuple(allocator_arg_t __tag, const _Alloc& __a,
+	      const _T1& __a1, const _T2& __a2)
+	: _Inherited(__tag, __a, __a1, __a2) { }
+
+      template<typename _Alloc, bool _Dummy = true,
+	       _ExplicitCtor<_Dummy, const _T1&, const _T2&> = false>
+	explicit
+	_GLIBCXX20_CONSTEXPR
+	tuple(allocator_arg_t __tag, const _Alloc& __a,
+	      const _T1& __a1, const _T2& __a2)
+	: _Inherited(__tag, __a, __a1, __a2) { }
+
+      template<typename _Alloc, typename _U1, typename _U2,
+	       _ImplicitCtor<true, _U1, _U2> = true>
+	_GLIBCXX20_CONSTEXPR
+	tuple(allocator_arg_t __tag, const _Alloc& __a, _U1&& __a1, _U2&& __a2)
+	: _Inherited(__tag, __a, std::forward<_U1>(__a1),
+	             std::forward<_U2>(__a2)) { }
+
+      template<typename _Alloc, typename _U1, typename _U2,
+	       _ExplicitCtor<true, _U1, _U2> = false>
+	explicit
+	_GLIBCXX20_CONSTEXPR
+	tuple(allocator_arg_t __tag, const _Alloc& __a,
+	      _U1&& __a1, _U2&& __a2)
+	: _Inherited(__tag, __a, std::forward<_U1>(__a1),
+	             std::forward<_U2>(__a2)) { }
+
+      template<typename _Alloc>
+	_GLIBCXX20_CONSTEXPR
+	tuple(allocator_arg_t __tag, const _Alloc& __a, const tuple& __in)
+	: _Inherited(__tag, __a, static_cast<const _Inherited&>(__in)) { }
+
+      template<typename _Alloc>
+	_GLIBCXX20_CONSTEXPR
+	tuple(allocator_arg_t __tag, const _Alloc& __a, tuple&& __in)
+	: _Inherited(__tag, __a, static_cast<_Inherited&&>(__in)) { }
+
+      template<typename _Alloc, typename _U1, typename _U2,
+	       _ImplicitCtor<true, const _U1&, const _U2&> = true>
+	_GLIBCXX20_CONSTEXPR
+	tuple(allocator_arg_t __tag, const _Alloc& __a,
+	      const tuple<_U1, _U2>& __in)
+	: _Inherited(__tag, __a,
+	             static_cast<const _Tuple_impl<0, _U1, _U2>&>(__in))
+	{ }
+
+      template<typename _Alloc, typename _U1, typename _U2,
+	       _ExplicitCtor<true, const _U1&, const _U2&> = false>
+	explicit
+	_GLIBCXX20_CONSTEXPR
+	tuple(allocator_arg_t __tag, const _Alloc& __a,
+	      const tuple<_U1, _U2>& __in)
+	: _Inherited(__tag, __a,
+	             static_cast<const _Tuple_impl<0, _U1, _U2>&>(__in))
+	{ }
+
+      template<typename _Alloc, typename _U1, typename _U2,
+	       _ImplicitCtor<true, _U1, _U2> = true>
+	_GLIBCXX20_CONSTEXPR
+	tuple(allocator_arg_t __tag, const _Alloc& __a, tuple<_U1, _U2>&& __in)
+	: _Inherited(__tag, __a, static_cast<_Tuple_impl<0, _U1, _U2>&&>(__in))
+	{ }
+
+      template<typename _Alloc, typename _U1, typename _U2,
+	       _ExplicitCtor<true, _U1, _U2> = false>
+	explicit
+	_GLIBCXX20_CONSTEXPR
+	tuple(allocator_arg_t __tag, const _Alloc& __a, tuple<_U1, _U2>&& __in)
+	: _Inherited(__tag, __a, static_cast<_Tuple_impl<0, _U1, _U2>&&>(__in))
+	{ }
+
+      template<typename _Alloc, typename _U1, typename _U2,
+	       _ImplicitCtor<true, const _U1&, const _U2&> = true>
+	_GLIBCXX20_CONSTEXPR
+	tuple(allocator_arg_t __tag, const _Alloc& __a,
+	      const pair<_U1, _U2>& __in)
+	: _Inherited(__tag, __a, __in.first, __in.second) { }
+
+      template<typename _Alloc, typename _U1, typename _U2,
+	       _ExplicitCtor<true, const _U1&, const _U2&> = false>
+	explicit
+	_GLIBCXX20_CONSTEXPR
+	tuple(allocator_arg_t __tag, const _Alloc& __a,
+	      const pair<_U1, _U2>& __in)
+	: _Inherited(__tag, __a, __in.first, __in.second) { }
+
+      template<typename _Alloc, typename _U1, typename _U2,
+	       _ImplicitCtor<true, _U1, _U2> = true>
+	_GLIBCXX20_CONSTEXPR
+	tuple(allocator_arg_t __tag, const _Alloc& __a, pair<_U1, _U2>&& __in)
+	: _Inherited(__tag, __a, std::forward<_U1>(__in.first),
+		     std::forward<_U2>(__in.second)) { }
+
+      template<typename _Alloc, typename _U1, typename _U2,
+	       _ExplicitCtor<true, _U1, _U2> = false>
+	explicit
+	_GLIBCXX20_CONSTEXPR
+	tuple(allocator_arg_t __tag, const _Alloc& __a, pair<_U1, _U2>&& __in)
+	: _Inherited(__tag, __a, std::forward<_U1>(__in.first),
+		     std::forward<_U2>(__in.second)) { }
+
+      // Tuple assignment.
+
+      _GLIBCXX20_CONSTEXPR
+      tuple&
+      operator=(__conditional_t<__assignable<const _T1&, const _T2&>(),
+				const tuple&,
+				const __nonesuch&> __in)
+      noexcept(__nothrow_assignable<const _T1&, const _T2&>())
+      {
+	this->_M_assign(__in);
+	return *this;
+      }
+
+      _GLIBCXX20_CONSTEXPR
+      tuple&
+      operator=(__conditional_t<__assignable<_T1, _T2>(),
+				tuple&&,
+				__nonesuch&&> __in)
+      noexcept(__nothrow_assignable<_T1, _T2>())
+      {
+	this->_M_assign(std::move(__in));
+	return *this;
+      }
+
+      template<typename _U1, typename _U2>
+	_GLIBCXX20_CONSTEXPR
+	__enable_if_t<__assignable<const _U1&, const _U2&>(), tuple&>
+	operator=(const tuple<_U1, _U2>& __in)
+	noexcept(__nothrow_assignable<const _U1&, const _U2&>())
+	{
+	  this->_M_assign(__in);
+	  return *this;
+	}
+
+      template<typename _U1, typename _U2>
+	_GLIBCXX20_CONSTEXPR
+	__enable_if_t<__assignable<_U1, _U2>(), tuple&>
+	operator=(tuple<_U1, _U2>&& __in)
+	noexcept(__nothrow_assignable<_U1, _U2>())
+	{
+	  this->_M_assign(std::move(__in));
+	  return *this;
+	}
+
+      template<typename _U1, typename _U2>
+	_GLIBCXX20_CONSTEXPR
+	__enable_if_t<__assignable<const _U1&, const _U2&>(), tuple&>
+	operator=(const pair<_U1, _U2>& __in)
+	noexcept(__nothrow_assignable<const _U1&, const _U2&>())
+	{
+	  this->_M_head(*this) = __in.first;
+	  this->_M_tail(*this)._M_head(*this) = __in.second;
+	  return *this;
+	}
+
+      template<typename _U1, typename _U2>
+	_GLIBCXX20_CONSTEXPR
+	__enable_if_t<__assignable<_U1, _U2>(), tuple&>
+	operator=(pair<_U1, _U2>&& __in)
+	noexcept(__nothrow_assignable<_U1, _U2>())
+	{
+	  this->_M_head(*this) = std::forward<_U1>(__in.first);
+	  this->_M_tail(*this)._M_head(*this) = std::forward<_U2>(__in.second);
+	  return *this;
+	}
+
+      _GLIBCXX20_CONSTEXPR
+      void
+      swap(tuple& __in)
+      noexcept(__and_<__is_nothrow_swappable<_T1>,
+		      __is_nothrow_swappable<_T2>>::value)
+      { _Inherited::_M_swap(__in); }
+    };
+
+
+  /// class tuple_size
+  template<typename... _Elements>
+    struct tuple_size<tuple<_Elements...>>
+    : public integral_constant<size_t, sizeof...(_Elements)> { };
+
+#if __cplusplus >= 201703L
+  template<typename... _Types>
+    inline constexpr size_t tuple_size_v<tuple<_Types...>>
+      = sizeof...(_Types);
+
+  template<typename... _Types>
+    inline constexpr size_t tuple_size_v<const tuple<_Types...>>
+      = sizeof...(_Types);
+#endif
+
+  /// Trait to get the Ith element type from a tuple.
+  template<size_t __i, typename... _Types>
+    struct tuple_element<__i, tuple<_Types...>>
+    {
+      static_assert(__i < sizeof...(_Types), "tuple index must be in range");
+
+      using type = typename _Nth_type<__i, _Types...>::type;
+    };
+
+  template<size_t __i, typename _Head, typename... _Tail>
+    constexpr _Head&
+    __get_helper(_Tuple_impl<__i, _Head, _Tail...>& __t) noexcept
+    { return _Tuple_impl<__i, _Head, _Tail...>::_M_head(__t); }
+
+  template<size_t __i, typename _Head, typename... _Tail>
+    constexpr const _Head&
+    __get_helper(const _Tuple_impl<__i, _Head, _Tail...>& __t) noexcept
+    { return _Tuple_impl<__i, _Head, _Tail...>::_M_head(__t); }
+
+  // Deleted overload to improve diagnostics for invalid indices
+  template<size_t __i, typename... _Types>
+    __enable_if_t<(__i >= sizeof...(_Types))>
+    __get_helper(const tuple<_Types...>&) = delete;
+
+  /// Return a reference to the ith element of a tuple.
+  template<size_t __i, typename... _Elements>
+    constexpr __tuple_element_t<__i, tuple<_Elements...>>&
+    get(tuple<_Elements...>& __t) noexcept
+    { return std::__get_helper<__i>(__t); }
+
+  /// Return a const reference to the ith element of a const tuple.
+  template<size_t __i, typename... _Elements>
+    constexpr const __tuple_element_t<__i, tuple<_Elements...>>&
+    get(const tuple<_Elements...>& __t) noexcept
+    { return std::__get_helper<__i>(__t); }
+
+  /// Return an rvalue reference to the ith element of a tuple rvalue.
+  template<size_t __i, typename... _Elements>
+    constexpr __tuple_element_t<__i, tuple<_Elements...>>&&
+    get(tuple<_Elements...>&& __t) noexcept
+    {
+      typedef __tuple_element_t<__i, tuple<_Elements...>> __element_type;
+      return std::forward<__element_type>(std::__get_helper<__i>(__t));
+    }
+
+  /// Return a const rvalue reference to the ith element of a const tuple rvalue.
+  template<size_t __i, typename... _Elements>
+    constexpr const __tuple_element_t<__i, tuple<_Elements...>>&&
+    get(const tuple<_Elements...>&& __t) noexcept
+    {
+      typedef __tuple_element_t<__i, tuple<_Elements...>> __element_type;
+      return std::forward<const __element_type>(std::__get_helper<__i>(__t));
+    }
+
+  /// @cond undocumented
+  // Deleted overload chosen for invalid indices.
+  template<size_t __i, typename... _Elements>
+    constexpr __enable_if_t<(__i >= sizeof...(_Elements))>
+    get(const tuple<_Elements...>&) = delete;
+  /// @endcond
+
+#if __cplusplus >= 201402L
+
+#define __cpp_lib_tuples_by_type 201304L
+
+  /// Return a reference to the unique element of type _Tp of a tuple.
+  template <typename _Tp, typename... _Types>
+    constexpr _Tp&
+    get(tuple<_Types...>& __t) noexcept
+    {
+      constexpr size_t __idx = __find_uniq_type_in_pack<_Tp, _Types...>();
+      static_assert(__idx < sizeof...(_Types),
+	  "the type T in std::get<T> must occur exactly once in the tuple");
+      return std::__get_helper<__idx>(__t);
+    }
+
+  /// Return a reference to the unique element of type _Tp of a tuple rvalue.
+  template <typename _Tp, typename... _Types>
+    constexpr _Tp&&
+    get(tuple<_Types...>&& __t) noexcept
+    {
+      constexpr size_t __idx = __find_uniq_type_in_pack<_Tp, _Types...>();
+      static_assert(__idx < sizeof...(_Types),
+	  "the type T in std::get<T> must occur exactly once in the tuple");
+      return std::forward<_Tp>(std::__get_helper<__idx>(__t));
+    }
+
+  /// Return a const reference to the unique element of type _Tp of a tuple.
+  template <typename _Tp, typename... _Types>
+    constexpr const _Tp&
+    get(const tuple<_Types...>& __t) noexcept
+    {
+      constexpr size_t __idx = __find_uniq_type_in_pack<_Tp, _Types...>();
+      static_assert(__idx < sizeof...(_Types),
+	  "the type T in std::get<T> must occur exactly once in the tuple");
+      return std::__get_helper<__idx>(__t);
+    }
+
+  /// Return a const reference to the unique element of type _Tp of
+  /// a const tuple rvalue.
+  template <typename _Tp, typename... _Types>
+    constexpr const _Tp&&
+    get(const tuple<_Types...>&& __t) noexcept
+    {
+      constexpr size_t __idx = __find_uniq_type_in_pack<_Tp, _Types...>();
+      static_assert(__idx < sizeof...(_Types),
+	  "the type T in std::get<T> must occur exactly once in the tuple");
+      return std::forward<const _Tp>(std::__get_helper<__idx>(__t));
+    }
+#endif
+
+  // This class performs the comparison operations on tuples
+  template<typename _Tp, typename _Up, size_t __i, size_t __size>
+    struct __tuple_compare
+    {
+      static constexpr bool
+      __eq(const _Tp& __t, const _Up& __u)
+      {
+	return bool(std::get<__i>(__t) == std::get<__i>(__u))
+	  && __tuple_compare<_Tp, _Up, __i + 1, __size>::__eq(__t, __u);
+      }
+
+      static constexpr bool
+      __less(const _Tp& __t, const _Up& __u)
+      {
+	return bool(std::get<__i>(__t) < std::get<__i>(__u))
+	  || (!bool(std::get<__i>(__u) < std::get<__i>(__t))
+	      && __tuple_compare<_Tp, _Up, __i + 1, __size>::__less(__t, __u));
+      }
+    };
+
+  template<typename _Tp, typename _Up, size_t __size>
+    struct __tuple_compare<_Tp, _Up, __size, __size>
+    {
+      static constexpr bool
+      __eq(const _Tp&, const _Up&) { return true; }
+
+      static constexpr bool
+      __less(const _Tp&, const _Up&) { return false; }
+    };
+
+  template<typename... _TElements, typename... _UElements>
+    constexpr bool
+    operator==(const tuple<_TElements...>& __t,
+	       const tuple<_UElements...>& __u)
+    {
+      static_assert(sizeof...(_TElements) == sizeof...(_UElements),
+	  "tuple objects can only be compared if they have equal sizes.");
+      using __compare = __tuple_compare<tuple<_TElements...>,
+					tuple<_UElements...>,
+					0, sizeof...(_TElements)>;
+      return __compare::__eq(__t, __u);
+    }
+
+#if __cpp_lib_three_way_comparison
+  template<typename _Cat, typename _Tp, typename _Up>
+    constexpr _Cat
+    __tuple_cmp(const _Tp&, const _Up&, index_sequence<>)
+    { return _Cat::equivalent; }
+
+  template<typename _Cat, typename _Tp, typename _Up,
+	   size_t _Idx0, size_t... _Idxs>
+    constexpr _Cat
+    __tuple_cmp(const _Tp& __t, const _Up& __u,
+		index_sequence<_Idx0, _Idxs...>)
+    {
+      auto __c
+	= __detail::__synth3way(std::get<_Idx0>(__t), std::get<_Idx0>(__u));
+      if (__c != 0)
+	return __c;
+      return std::__tuple_cmp<_Cat>(__t, __u, index_sequence<_Idxs...>());
+    }
+
+  template<typename... _Tps, typename... _Ups>
+    constexpr
+    common_comparison_category_t<__detail::__synth3way_t<_Tps, _Ups>...>
+    operator<=>(const tuple<_Tps...>& __t, const tuple<_Ups...>& __u)
+    {
+      using _Cat
+	= common_comparison_category_t<__detail::__synth3way_t<_Tps, _Ups>...>;
+      return std::__tuple_cmp<_Cat>(__t, __u, index_sequence_for<_Tps...>());
+    }
+#else
+  template<typename... _TElements, typename... _UElements>
+    constexpr bool
+    operator<(const tuple<_TElements...>& __t,
+	      const tuple<_UElements...>& __u)
+    {
+      static_assert(sizeof...(_TElements) == sizeof...(_UElements),
+	  "tuple objects can only be compared if they have equal sizes.");
+      using __compare = __tuple_compare<tuple<_TElements...>,
+					tuple<_UElements...>,
+					0, sizeof...(_TElements)>;
+      return __compare::__less(__t, __u);
+    }
+
+  template<typename... _TElements, typename... _UElements>
+    constexpr bool
+    operator!=(const tuple<_TElements...>& __t,
+	       const tuple<_UElements...>& __u)
+    { return !(__t == __u); }
+
+  template<typename... _TElements, typename... _UElements>
+    constexpr bool
+    operator>(const tuple<_TElements...>& __t,
+	      const tuple<_UElements...>& __u)
+    { return __u < __t; }
+
+  template<typename... _TElements, typename... _UElements>
+    constexpr bool
+    operator<=(const tuple<_TElements...>& __t,
+	       const tuple<_UElements...>& __u)
+    { return !(__u < __t); }
+
+  template<typename... _TElements, typename... _UElements>
+    constexpr bool
+    operator>=(const tuple<_TElements...>& __t,
+	       const tuple<_UElements...>& __u)
+    { return !(__t < __u); }
+#endif // three_way_comparison
+
+  // NB: DR 705.
+  template<typename... _Elements>
+    constexpr tuple<typename __decay_and_strip<_Elements>::__type...>
+    make_tuple(_Elements&&... __args)
+    {
+      typedef tuple<typename __decay_and_strip<_Elements>::__type...>
+	__result_type;
+      return __result_type(std::forward<_Elements>(__args)...);
+    }
+
+  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+  // 2275. Why is forward_as_tuple not constexpr?
+  /// std::forward_as_tuple
+  template<typename... _Elements>
+    constexpr tuple<_Elements&&...>
+    forward_as_tuple(_Elements&&... __args) noexcept
+    { return tuple<_Elements&&...>(std::forward<_Elements>(__args)...); }
+
+  // Declarations of std::array and its std::get overloads, so that
+  // std::tuple_cat can use them if <tuple> is included before <array>.
+
+  template<typename _Tp, size_t _Nm> struct array;
+
+  template<size_t _Int, typename _Tp, size_t _Nm>
+    constexpr _Tp&
+    get(array<_Tp, _Nm>&) noexcept;
+
+  template<size_t _Int, typename _Tp, size_t _Nm>
+    constexpr _Tp&&
+    get(array<_Tp, _Nm>&&) noexcept;
+
+  template<size_t _Int, typename _Tp, size_t _Nm>
+    constexpr const _Tp&
+    get(const array<_Tp, _Nm>&) noexcept;
+
+  template<size_t _Int, typename _Tp, size_t _Nm>
+    constexpr const _Tp&&
+    get(const array<_Tp, _Nm>&&) noexcept;
+
+
+  template<size_t, typename, typename, size_t>
+    struct __make_tuple_impl;
+
+  template<size_t _Idx, typename _Tuple, typename... _Tp, size_t _Nm>
+    struct __make_tuple_impl<_Idx, tuple<_Tp...>, _Tuple, _Nm>
+    : __make_tuple_impl<_Idx + 1,
+			tuple<_Tp..., __tuple_element_t<_Idx, _Tuple>>,
+			_Tuple, _Nm>
+    { };
+
+  template<size_t _Nm, typename _Tuple, typename... _Tp>
+    struct __make_tuple_impl<_Nm, tuple<_Tp...>, _Tuple, _Nm>
+    {
+      typedef tuple<_Tp...> __type;
+    };
+
+  template<typename _Tuple>
+    struct __do_make_tuple
+    : __make_tuple_impl<0, tuple<>, _Tuple, tuple_size<_Tuple>::value>
+    { };
+
+  // Returns the std::tuple equivalent of a tuple-like type.
+  template<typename _Tuple>
+    struct __make_tuple
+    : public __do_make_tuple<__remove_cvref_t<_Tuple>>
+    { };
+
+  // Combines several std::tuple's into a single one.
+  template<typename...>
+    struct __combine_tuples;
+
+  template<>
+    struct __combine_tuples<>
+    {
+      typedef tuple<> __type;
+    };
+
+  template<typename... _Ts>
+    struct __combine_tuples<tuple<_Ts...>>
+    {
+      typedef tuple<_Ts...> __type;
+    };
+
+  template<typename... _T1s, typename... _T2s, typename... _Rem>
+    struct __combine_tuples<tuple<_T1s...>, tuple<_T2s...>, _Rem...>
+    {
+      typedef typename __combine_tuples<tuple<_T1s..., _T2s...>,
+					_Rem...>::__type __type;
+    };
+
+  // Computes the result type of tuple_cat given a set of tuple-like types.
+  template<typename... _Tpls>
+    struct __tuple_cat_result
+    {
+      typedef typename __combine_tuples
+        <typename __make_tuple<_Tpls>::__type...>::__type __type;
+    };
+
+  // Helper to determine the index set for the first tuple-like
+  // type of a given set.
+  template<typename...>
+    struct __make_1st_indices;
+
+  template<>
+    struct __make_1st_indices<>
+    {
+      typedef _Index_tuple<> __type;
+    };
+
+  template<typename _Tp, typename... _Tpls>
+    struct __make_1st_indices<_Tp, _Tpls...>
+    {
+      typedef typename _Build_index_tuple<tuple_size<
+	typename remove_reference<_Tp>::type>::value>::__type __type;
+    };
+
+  // Performs the actual concatenation by step-wise expanding tuple-like
+  // objects into the elements,  which are finally forwarded into the
+  // result tuple.
+  template<typename _Ret, typename _Indices, typename... _Tpls>
+    struct __tuple_concater;
+
+  template<typename _Ret, size_t... _Is, typename _Tp, typename... _Tpls>
+    struct __tuple_concater<_Ret, _Index_tuple<_Is...>, _Tp, _Tpls...>
+    {
+      template<typename... _Us>
+        static constexpr _Ret
+        _S_do(_Tp&& __tp, _Tpls&&... __tps, _Us&&... __us)
+        {
+	  typedef typename __make_1st_indices<_Tpls...>::__type __idx;
+	  typedef __tuple_concater<_Ret, __idx, _Tpls...>      __next;
+	  return __next::_S_do(std::forward<_Tpls>(__tps)...,
+			       std::forward<_Us>(__us)...,
+			       std::get<_Is>(std::forward<_Tp>(__tp))...);
+	}
+    };
+
+  template<typename _Ret>
+    struct __tuple_concater<_Ret, _Index_tuple<>>
+    {
+      template<typename... _Us>
+	static constexpr _Ret
+	_S_do(_Us&&... __us)
+        {
+	  return _Ret(std::forward<_Us>(__us)...);
+	}
+    };
+
+  template<typename... _Tps>
+    struct __is_tuple_like_impl<tuple<_Tps...>> : true_type
+    { };
+
+  /// tuple_cat
+  template<typename... _Tpls, typename = typename
+           enable_if<__and_<__is_tuple_like<_Tpls>...>::value>::type>
+    constexpr auto
+    tuple_cat(_Tpls&&... __tpls)
+    -> typename __tuple_cat_result<_Tpls...>::__type
+    {
+      typedef typename __tuple_cat_result<_Tpls...>::__type __ret;
+      typedef typename __make_1st_indices<_Tpls...>::__type __idx;
+      typedef __tuple_concater<__ret, __idx, _Tpls...> __concater;
+      return __concater::_S_do(std::forward<_Tpls>(__tpls)...);
+    }
+
+  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+  // 2301. Why is tie not constexpr?
+  /// tie
+  template<typename... _Elements>
+    constexpr tuple<_Elements&...>
+    tie(_Elements&... __args) noexcept
+    { return tuple<_Elements&...>(__args...); }
+
+  /// swap
+  template<typename... _Elements>
+    _GLIBCXX20_CONSTEXPR
+    inline
+#if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11
+    // Constrained free swap overload, see p0185r1
+    typename enable_if<__and_<__is_swappable<_Elements>...>::value
+      >::type
+#else
+    void
+#endif
+    swap(tuple<_Elements...>& __x, tuple<_Elements...>& __y)
+    noexcept(noexcept(__x.swap(__y)))
+    { __x.swap(__y); }
+
+#if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11
+  template<typename... _Elements>
+    _GLIBCXX20_CONSTEXPR
+    typename enable_if<!__and_<__is_swappable<_Elements>...>::value>::type
+    swap(tuple<_Elements...>&, tuple<_Elements...>&) = delete;
+#endif
+
+  // A class (and instance) which can be used in 'tie' when an element
+  // of a tuple is not required.
+  // _GLIBCXX14_CONSTEXPR
+  // 2933. PR for LWG 2773 could be clearer
+  struct _Swallow_assign
+  {
+    template<class _Tp>
+      _GLIBCXX14_CONSTEXPR const _Swallow_assign&
+      operator=(const _Tp&) const
+      { return *this; }
+  };
+
+  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+  // 2773. Making std::ignore constexpr
+  _GLIBCXX17_INLINE constexpr _Swallow_assign ignore{};
+
+  /// Partial specialization for tuples
+  template<typename... _Types, typename _Alloc>
+    struct uses_allocator<tuple<_Types...>, _Alloc> : true_type { };
+
+  // See stl_pair.h...
+  /** "piecewise construction" using a tuple of arguments for each member.
+   *
+   * @param __first Arguments for the first member of the pair.
+   * @param __second Arguments for the second member of the pair.
+   *
+   * The elements of each tuple will be used as the constructor arguments
+   * for the data members of the pair.
+  */
+  template<class _T1, class _T2>
+    template<typename... _Args1, typename... _Args2>
+      _GLIBCXX20_CONSTEXPR
+      inline
+      pair<_T1, _T2>::
+      pair(piecewise_construct_t,
+	   tuple<_Args1...> __first, tuple<_Args2...> __second)
+      : pair(__first, __second,
+	     typename _Build_index_tuple<sizeof...(_Args1)>::__type(),
+	     typename _Build_index_tuple<sizeof...(_Args2)>::__type())
+      { }
+
+  template<class _T1, class _T2>
+    template<typename... _Args1, size_t... _Indexes1,
+	     typename... _Args2, size_t... _Indexes2>
+      _GLIBCXX20_CONSTEXPR inline
+      pair<_T1, _T2>::
+      pair(tuple<_Args1...>& __tuple1, tuple<_Args2...>& __tuple2,
+	   _Index_tuple<_Indexes1...>, _Index_tuple<_Indexes2...>)
+      : first(std::forward<_Args1>(std::get<_Indexes1>(__tuple1))...),
+	second(std::forward<_Args2>(std::get<_Indexes2>(__tuple2))...)
+      { }
+
+#if __cplusplus >= 201703L
+
+  // Unpack a std::tuple into a type trait and use its value.
+  // For cv std::tuple<_Up> the result is _Trait<_Tp, cv _Up...>::value.
+  // For cv std::tuple<_Up>& the result is _Trait<_Tp, cv _Up&...>::value.
+  // Otherwise the result is false (because we don't know if std::get throws).
+  template<template<typename...> class _Trait, typename _Tp, typename _Tuple>
+    inline constexpr bool __unpack_std_tuple = false;
+
+  template<template<typename...> class _Trait, typename _Tp, typename... _Up>
+    inline constexpr bool __unpack_std_tuple<_Trait, _Tp, tuple<_Up...>>
+      = _Trait<_Tp, _Up...>::value;
+
+  template<template<typename...> class _Trait, typename _Tp, typename... _Up>
+    inline constexpr bool __unpack_std_tuple<_Trait, _Tp, tuple<_Up...>&>
+      = _Trait<_Tp, _Up&...>::value;
+
+  template<template<typename...> class _Trait, typename _Tp, typename... _Up>
+    inline constexpr bool __unpack_std_tuple<_Trait, _Tp, const tuple<_Up...>>
+      = _Trait<_Tp, const _Up...>::value;
+
+  template<template<typename...> class _Trait, typename _Tp, typename... _Up>
+    inline constexpr bool __unpack_std_tuple<_Trait, _Tp, const tuple<_Up...>&>
+      = _Trait<_Tp, const _Up&...>::value;
+
+# define __cpp_lib_apply 201603L
+
+  template <typename _Fn, typename _Tuple, size_t... _Idx>
+    constexpr decltype(auto)
+    __apply_impl(_Fn&& __f, _Tuple&& __t, index_sequence<_Idx...>)
+    {
+      return std::__invoke(std::forward<_Fn>(__f),
+			   std::get<_Idx>(std::forward<_Tuple>(__t))...);
+    }
+
+  template <typename _Fn, typename _Tuple>
+    constexpr decltype(auto)
+    apply(_Fn&& __f, _Tuple&& __t)
+    noexcept(__unpack_std_tuple<is_nothrow_invocable, _Fn, _Tuple>)
+    {
+      using _Indices
+	= make_index_sequence<tuple_size_v<remove_reference_t<_Tuple>>>;
+      return std::__apply_impl(std::forward<_Fn>(__f),
+			       std::forward<_Tuple>(__t),
+			       _Indices{});
+    }
+
+#define __cpp_lib_make_from_tuple  201606L
+
+  template <typename _Tp, typename _Tuple, size_t... _Idx>
+    constexpr _Tp
+    __make_from_tuple_impl(_Tuple&& __t, index_sequence<_Idx...>)
+    { return _Tp(std::get<_Idx>(std::forward<_Tuple>(__t))...); }
+
+  template <typename _Tp, typename _Tuple>
+    constexpr _Tp
+    make_from_tuple(_Tuple&& __t)
+    noexcept(__unpack_std_tuple<is_nothrow_constructible, _Tp, _Tuple>)
+    {
+      return __make_from_tuple_impl<_Tp>(
+        std::forward<_Tuple>(__t),
+	make_index_sequence<tuple_size_v<remove_reference_t<_Tuple>>>{});
+    }
+#endif // C++17
+
+  /// @}
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif // C++11
+
+#endif // _GLIBCXX_TUPLE
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@tuple.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@tuple.blob
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Binary files /dev/null and b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@tuple.blob differ
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@type_traits b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@type_traits
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--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@type_traits
@@ -0,0 +1,3708 @@
+// C++11 <type_traits> -*- C++ -*-
+
+// Copyright (C) 2007-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file include/type_traits
+ *  This is a Standard C++ Library header.
+ */
+
+#ifndef _GLIBCXX_TYPE_TRAITS
+#define _GLIBCXX_TYPE_TRAITS 1
+
+#pragma GCC system_header
+
+#if __cplusplus < 201103L
+# include <bits/c++0x_warning.h>
+#else
+
+#include <bits/c++config.h>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  template<typename _Tp>
+    class reference_wrapper;
+
+  /**
+   * @defgroup metaprogramming Metaprogramming
+   * @ingroup utilities
+   *
+   * Template utilities for compile-time introspection and modification,
+   * including type classification traits, type property inspection traits
+   * and type transformation traits.
+   *
+   * @since C++11
+   *
+   * @{
+   */
+
+  /// integral_constant
+  template<typename _Tp, _Tp __v>
+    struct integral_constant
+    {
+      static constexpr _Tp                  value = __v;
+      typedef _Tp                           value_type;
+      typedef integral_constant<_Tp, __v>   type;
+      constexpr operator value_type() const noexcept { return value; }
+#if __cplusplus > 201103L
+
+#define __cpp_lib_integral_constant_callable 201304L
+
+      constexpr value_type operator()() const noexcept { return value; }
+#endif
+    };
+
+#if ! __cpp_inline_variables
+  template<typename _Tp, _Tp __v>
+    constexpr _Tp integral_constant<_Tp, __v>::value;
+#endif
+
+  /// The type used as a compile-time boolean with true value.
+  using true_type =  integral_constant<bool, true>;
+
+  /// The type used as a compile-time boolean with false value.
+  using false_type = integral_constant<bool, false>;
+
+  /// @cond undocumented
+  /// bool_constant for C++11
+  template<bool __v>
+    using __bool_constant = integral_constant<bool, __v>;
+  /// @endcond
+
+#if __cplusplus >= 201703L
+# define __cpp_lib_bool_constant 201505L
+  /// Alias template for compile-time boolean constant types.
+  /// @since C++17
+  template<bool __v>
+    using bool_constant = integral_constant<bool, __v>;
+#endif
+
+  // Metaprogramming helper types.
+
+  template<bool>
+    struct __conditional
+    {
+      template<typename _Tp, typename>
+	using type = _Tp;
+    };
+
+  template<>
+    struct __conditional<false>
+    {
+      template<typename, typename _Up>
+	using type = _Up;
+    };
+
+  // More efficient version of std::conditional_t for internal use (and C++11)
+  template<bool _Cond, typename _If, typename _Else>
+    using __conditional_t
+      = typename __conditional<_Cond>::template type<_If, _Else>;
+
+  /// @cond undocumented
+  template <typename _Type>
+    struct __type_identity
+    { using type = _Type; };
+
+  template<typename _Tp>
+    using __type_identity_t = typename __type_identity<_Tp>::type;
+
+  template<typename...>
+    struct __or_;
+
+  template<>
+    struct __or_<>
+    : public false_type
+    { };
+
+  template<typename _B1>
+    struct __or_<_B1>
+    : public _B1
+    { };
+
+  template<typename _B1, typename _B2>
+    struct __or_<_B1, _B2>
+    : public __conditional_t<_B1::value, _B1, _B2>
+    { };
+
+  template<typename _B1, typename _B2, typename _B3, typename... _Bn>
+    struct __or_<_B1, _B2, _B3, _Bn...>
+    : public __conditional_t<_B1::value, _B1, __or_<_B2, _B3, _Bn...>>
+    { };
+
+  template<typename...>
+    struct __and_;
+
+  template<>
+    struct __and_<>
+    : public true_type
+    { };
+
+  template<typename _B1>
+    struct __and_<_B1>
+    : public _B1
+    { };
+
+  template<typename _B1, typename _B2>
+    struct __and_<_B1, _B2>
+    : public __conditional_t<_B1::value, _B2, _B1>
+    { };
+
+  template<typename _B1, typename _B2, typename _B3, typename... _Bn>
+    struct __and_<_B1, _B2, _B3, _Bn...>
+    : public __conditional_t<_B1::value, __and_<_B2, _B3, _Bn...>, _B1>
+    { };
+
+  template<typename _Pp>
+    struct __not_
+    : public __bool_constant<!bool(_Pp::value)>
+    { };
+  /// @endcond
+
+#if __cplusplus >= 201703L
+
+  /// @cond undocumented
+  template<typename... _Bn>
+    inline constexpr bool __or_v = __or_<_Bn...>::value;
+  template<typename... _Bn>
+    inline constexpr bool __and_v = __and_<_Bn...>::value;
+  /// @endcond
+
+#define __cpp_lib_logical_traits 201510L
+
+  template<typename... _Bn>
+    struct conjunction
+    : __and_<_Bn...>
+    { };
+
+  template<typename... _Bn>
+    struct disjunction
+    : __or_<_Bn...>
+    { };
+
+  template<typename _Pp>
+    struct negation
+    : __not_<_Pp>
+    { };
+
+  /** @ingroup variable_templates
+   * @{
+   */
+  template<typename... _Bn>
+    inline constexpr bool conjunction_v = conjunction<_Bn...>::value;
+
+  template<typename... _Bn>
+    inline constexpr bool disjunction_v = disjunction<_Bn...>::value;
+
+  template<typename _Pp>
+    inline constexpr bool negation_v = negation<_Pp>::value;
+  /// @}
+
+#endif // C++17
+
+  // Forward declarations
+  template<typename>
+    struct is_reference;
+  template<typename>
+    struct is_function;
+  template<typename>
+    struct is_void;
+  template<typename>
+    struct remove_cv;
+  template<typename>
+    struct is_const;
+
+  /// @cond undocumented
+  template<typename>
+    struct __is_array_unknown_bounds;
+
+  // Helper functions that return false_type for incomplete classes,
+  // incomplete unions and arrays of known bound from those.
+
+  template <typename _Tp, size_t = sizeof(_Tp)>
+    constexpr true_type __is_complete_or_unbounded(__type_identity<_Tp>)
+    { return {}; }
+
+  template <typename _TypeIdentity,
+      typename _NestedType = typename _TypeIdentity::type>
+    constexpr typename __or_<
+      is_reference<_NestedType>,
+      is_function<_NestedType>,
+      is_void<_NestedType>,
+      __is_array_unknown_bounds<_NestedType>
+    >::type __is_complete_or_unbounded(_TypeIdentity)
+    { return {}; }
+
+  // For several sfinae-friendly trait implementations we transport both the
+  // result information (as the member type) and the failure information (no
+  // member type). This is very similar to std::enable_if, but we cannot use
+  // them, because we need to derive from them as an implementation detail.
+
+  template<typename _Tp>
+    struct __success_type
+    { typedef _Tp type; };
+
+  struct __failure_type
+  { };
+
+  // __remove_cv_t (std::remove_cv_t for C++11).
+  template<typename _Tp>
+    using __remove_cv_t = typename remove_cv<_Tp>::type;
+
+  // Primary type categories.
+
+  template<typename>
+    struct __is_void_helper
+    : public false_type { };
+
+  template<>
+    struct __is_void_helper<void>
+    : public true_type { };
+  /// @endcond
+
+  /// is_void
+  template<typename _Tp>
+    struct is_void
+    : public __is_void_helper<__remove_cv_t<_Tp>>::type
+    { };
+
+  /// @cond undocumented
+  template<typename>
+    struct __is_integral_helper
+    : public false_type { };
+
+  template<>
+    struct __is_integral_helper<bool>
+    : public true_type { };
+
+  template<>
+    struct __is_integral_helper<char>
+    : public true_type { };
+
+  template<>
+    struct __is_integral_helper<signed char>
+    : public true_type { };
+
+  template<>
+    struct __is_integral_helper<unsigned char>
+    : public true_type { };
+
+  // We want is_integral<wchar_t> to be true (and make_signed/unsigned to work)
+  // even when libc doesn't provide working <wchar.h> and related functions,
+  // so don't check _GLIBCXX_USE_WCHAR_T here.
+  template<>
+    struct __is_integral_helper<wchar_t>
+    : public true_type { };
+
+#ifdef _GLIBCXX_USE_CHAR8_T
+  template<>
+    struct __is_integral_helper<char8_t>
+    : public true_type { };
+#endif
+
+  template<>
+    struct __is_integral_helper<char16_t>
+    : public true_type { };
+
+  template<>
+    struct __is_integral_helper<char32_t>
+    : public true_type { };
+
+  template<>
+    struct __is_integral_helper<short>
+    : public true_type { };
+
+  template<>
+    struct __is_integral_helper<unsigned short>
+    : public true_type { };
+
+  template<>
+    struct __is_integral_helper<int>
+    : public true_type { };
+
+  template<>
+    struct __is_integral_helper<unsigned int>
+    : public true_type { };
+
+  template<>
+    struct __is_integral_helper<long>
+    : public true_type { };
+
+  template<>
+    struct __is_integral_helper<unsigned long>
+    : public true_type { };
+
+  template<>
+    struct __is_integral_helper<long long>
+    : public true_type { };
+
+  template<>
+    struct __is_integral_helper<unsigned long long>
+    : public true_type { };
+
+  // Conditionalizing on __STRICT_ANSI__ here will break any port that
+  // uses one of these types for size_t.
+#if defined(__GLIBCXX_TYPE_INT_N_0)
+  __extension__
+  template<>
+    struct __is_integral_helper<__GLIBCXX_TYPE_INT_N_0>
+    : public true_type { };
+
+  __extension__
+  template<>
+    struct __is_integral_helper<unsigned __GLIBCXX_TYPE_INT_N_0>
+    : public true_type { };
+#endif
+#if defined(__GLIBCXX_TYPE_INT_N_1)
+  __extension__
+  template<>
+    struct __is_integral_helper<__GLIBCXX_TYPE_INT_N_1>
+    : public true_type { };
+
+  __extension__
+  template<>
+    struct __is_integral_helper<unsigned __GLIBCXX_TYPE_INT_N_1>
+    : public true_type { };
+#endif
+#if defined(__GLIBCXX_TYPE_INT_N_2)
+  __extension__
+  template<>
+    struct __is_integral_helper<__GLIBCXX_TYPE_INT_N_2>
+    : public true_type { };
+
+  __extension__
+  template<>
+    struct __is_integral_helper<unsigned __GLIBCXX_TYPE_INT_N_2>
+    : public true_type { };
+#endif
+#if defined(__GLIBCXX_TYPE_INT_N_3)
+  __extension__
+  template<>
+    struct __is_integral_helper<__GLIBCXX_TYPE_INT_N_3>
+    : public true_type { };
+
+  __extension__
+  template<>
+    struct __is_integral_helper<unsigned __GLIBCXX_TYPE_INT_N_3>
+    : public true_type { };
+#endif
+  /// @endcond
+
+  /// is_integral
+  template<typename _Tp>
+    struct is_integral
+    : public __is_integral_helper<__remove_cv_t<_Tp>>::type
+    { };
+
+  /// @cond undocumented
+  template<typename>
+    struct __is_floating_point_helper
+    : public false_type { };
+
+  template<>
+    struct __is_floating_point_helper<float>
+    : public true_type { };
+
+  template<>
+    struct __is_floating_point_helper<double>
+    : public true_type { };
+
+  template<>
+    struct __is_floating_point_helper<long double>
+    : public true_type { };
+
+#if !defined(__STRICT_ANSI__) && defined(_GLIBCXX_USE_FLOAT128)
+  template<>
+    struct __is_floating_point_helper<__float128>
+    : public true_type { };
+#endif
+  /// @endcond
+
+  /// is_floating_point
+  template<typename _Tp>
+    struct is_floating_point
+    : public __is_floating_point_helper<__remove_cv_t<_Tp>>::type
+    { };
+
+  /// is_array
+  template<typename>
+    struct is_array
+    : public false_type { };
+
+  template<typename _Tp, std::size_t _Size>
+    struct is_array<_Tp[_Size]>
+    : public true_type { };
+
+  template<typename _Tp>
+    struct is_array<_Tp[]>
+    : public true_type { };
+
+  template<typename>
+    struct __is_pointer_helper
+    : public false_type { };
+
+  template<typename _Tp>
+    struct __is_pointer_helper<_Tp*>
+    : public true_type { };
+
+  /// is_pointer
+  template<typename _Tp>
+    struct is_pointer
+    : public __is_pointer_helper<__remove_cv_t<_Tp>>::type
+    { };
+
+  /// is_lvalue_reference
+  template<typename>
+    struct is_lvalue_reference
+    : public false_type { };
+
+  template<typename _Tp>
+    struct is_lvalue_reference<_Tp&>
+    : public true_type { };
+
+  /// is_rvalue_reference
+  template<typename>
+    struct is_rvalue_reference
+    : public false_type { };
+
+  template<typename _Tp>
+    struct is_rvalue_reference<_Tp&&>
+    : public true_type { };
+
+  template<typename>
+    struct __is_member_object_pointer_helper
+    : public false_type { };
+
+  template<typename _Tp, typename _Cp>
+    struct __is_member_object_pointer_helper<_Tp _Cp::*>
+    : public __not_<is_function<_Tp>>::type { };
+
+  /// is_member_object_pointer
+  template<typename _Tp>
+    struct is_member_object_pointer
+    : public __is_member_object_pointer_helper<__remove_cv_t<_Tp>>::type
+    { };
+
+  template<typename>
+    struct __is_member_function_pointer_helper
+    : public false_type { };
+
+  template<typename _Tp, typename _Cp>
+    struct __is_member_function_pointer_helper<_Tp _Cp::*>
+    : public is_function<_Tp>::type { };
+
+  /// is_member_function_pointer
+  template<typename _Tp>
+    struct is_member_function_pointer
+    : public __is_member_function_pointer_helper<__remove_cv_t<_Tp>>::type
+    { };
+
+  /// is_enum
+  template<typename _Tp>
+    struct is_enum
+    : public integral_constant<bool, __is_enum(_Tp)>
+    { };
+
+  /// is_union
+  template<typename _Tp>
+    struct is_union
+    : public integral_constant<bool, __is_union(_Tp)>
+    { };
+
+  /// is_class
+  template<typename _Tp>
+    struct is_class
+    : public integral_constant<bool, __is_class(_Tp)>
+    { };
+
+  /// is_function
+  template<typename _Tp>
+    struct is_function
+    : public __bool_constant<!is_const<const _Tp>::value> { };
+
+  template<typename _Tp>
+    struct is_function<_Tp&>
+    : public false_type { };
+
+  template<typename _Tp>
+    struct is_function<_Tp&&>
+    : public false_type { };
+
+#define __cpp_lib_is_null_pointer 201309L
+
+  template<typename>
+    struct __is_null_pointer_helper
+    : public false_type { };
+
+  template<>
+    struct __is_null_pointer_helper<std::nullptr_t>
+    : public true_type { };
+
+  /// is_null_pointer (LWG 2247).
+  template<typename _Tp>
+    struct is_null_pointer
+    : public __is_null_pointer_helper<__remove_cv_t<_Tp>>::type
+    { };
+
+  /// __is_nullptr_t (deprecated extension).
+  /// @deprecated Non-standard. Use `is_null_pointer` instead.
+  template<typename _Tp>
+    struct __is_nullptr_t
+    : public is_null_pointer<_Tp>
+    { } _GLIBCXX_DEPRECATED_SUGGEST("std::is_null_pointer");
+
+  // Composite type categories.
+
+  /// is_reference
+  template<typename _Tp>
+    struct is_reference
+    : public __or_<is_lvalue_reference<_Tp>,
+                   is_rvalue_reference<_Tp>>::type
+    { };
+
+  /// is_arithmetic
+  template<typename _Tp>
+    struct is_arithmetic
+    : public __or_<is_integral<_Tp>, is_floating_point<_Tp>>::type
+    { };
+
+  /// is_fundamental
+  template<typename _Tp>
+    struct is_fundamental
+    : public __or_<is_arithmetic<_Tp>, is_void<_Tp>,
+		   is_null_pointer<_Tp>>::type
+    { };
+
+  /// is_object
+  template<typename _Tp>
+    struct is_object
+    : public __not_<__or_<is_function<_Tp>, is_reference<_Tp>,
+                          is_void<_Tp>>>::type
+    { };
+
+  template<typename>
+    struct is_member_pointer;
+
+  /// is_scalar
+  template<typename _Tp>
+    struct is_scalar
+    : public __or_<is_arithmetic<_Tp>, is_enum<_Tp>, is_pointer<_Tp>,
+                   is_member_pointer<_Tp>, is_null_pointer<_Tp>>::type
+    { };
+
+  /// is_compound
+  template<typename _Tp>
+    struct is_compound
+    : public __not_<is_fundamental<_Tp>>::type { };
+
+  /// @cond undocumented
+  template<typename _Tp>
+    struct __is_member_pointer_helper
+    : public false_type { };
+
+  template<typename _Tp, typename _Cp>
+    struct __is_member_pointer_helper<_Tp _Cp::*>
+    : public true_type { };
+  /// @endcond
+
+  /// is_member_pointer
+  template<typename _Tp>
+    struct is_member_pointer
+    : public __is_member_pointer_helper<__remove_cv_t<_Tp>>::type
+    { };
+
+  template<typename, typename>
+    struct is_same;
+
+  /// @cond undocumented
+  template<typename _Tp, typename... _Types>
+    using __is_one_of = __or_<is_same<_Tp, _Types>...>;
+
+  // Check if a type is one of the signed integer types.
+  __extension__
+  template<typename _Tp>
+    using __is_signed_integer = __is_one_of<__remove_cv_t<_Tp>,
+	  signed char, signed short, signed int, signed long,
+	  signed long long
+#if defined(__GLIBCXX_TYPE_INT_N_0)
+	  , signed __GLIBCXX_TYPE_INT_N_0
+#endif
+#if defined(__GLIBCXX_TYPE_INT_N_1)
+	  , signed __GLIBCXX_TYPE_INT_N_1
+#endif
+#if defined(__GLIBCXX_TYPE_INT_N_2)
+	  , signed __GLIBCXX_TYPE_INT_N_2
+#endif
+#if defined(__GLIBCXX_TYPE_INT_N_3)
+	  , signed __GLIBCXX_TYPE_INT_N_3
+#endif
+	  >;
+
+  // Check if a type is one of the unsigned integer types.
+  __extension__
+  template<typename _Tp>
+    using __is_unsigned_integer = __is_one_of<__remove_cv_t<_Tp>,
+	  unsigned char, unsigned short, unsigned int, unsigned long,
+	  unsigned long long
+#if defined(__GLIBCXX_TYPE_INT_N_0)
+	  , unsigned __GLIBCXX_TYPE_INT_N_0
+#endif
+#if defined(__GLIBCXX_TYPE_INT_N_1)
+	  , unsigned __GLIBCXX_TYPE_INT_N_1
+#endif
+#if defined(__GLIBCXX_TYPE_INT_N_2)
+	  , unsigned __GLIBCXX_TYPE_INT_N_2
+#endif
+#if defined(__GLIBCXX_TYPE_INT_N_3)
+	  , unsigned __GLIBCXX_TYPE_INT_N_3
+#endif
+	  >;
+
+  // Check if a type is one of the signed or unsigned integer types.
+  template<typename _Tp>
+    using __is_standard_integer
+      = __or_<__is_signed_integer<_Tp>, __is_unsigned_integer<_Tp>>;
+
+  // __void_t (std::void_t for C++11)
+  template<typename...> using __void_t = void;
+
+  // Utility to detect referenceable types ([defns.referenceable]).
+
+  template<typename _Tp, typename = void>
+    struct __is_referenceable
+    : public false_type
+    { };
+
+  template<typename _Tp>
+    struct __is_referenceable<_Tp, __void_t<_Tp&>>
+    : public true_type
+    { };
+  /// @endcond
+
+  // Type properties.
+
+  /// is_const
+  template<typename>
+    struct is_const
+    : public false_type { };
+
+  template<typename _Tp>
+    struct is_const<_Tp const>
+    : public true_type { };
+
+  /// is_volatile
+  template<typename>
+    struct is_volatile
+    : public false_type { };
+
+  template<typename _Tp>
+    struct is_volatile<_Tp volatile>
+    : public true_type { };
+
+  /// is_trivial
+  template<typename _Tp>
+    struct is_trivial
+    : public integral_constant<bool, __is_trivial(_Tp)>
+    {
+      static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
+	"template argument must be a complete class or an unbounded array");
+    };
+
+  /// is_trivially_copyable
+  template<typename _Tp>
+    struct is_trivially_copyable
+    : public integral_constant<bool, __is_trivially_copyable(_Tp)>
+    {
+      static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
+	"template argument must be a complete class or an unbounded array");
+    };
+
+  /// is_standard_layout
+  template<typename _Tp>
+    struct is_standard_layout
+    : public integral_constant<bool, __is_standard_layout(_Tp)>
+    {
+      static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
+	"template argument must be a complete class or an unbounded array");
+    };
+
+  /** is_pod
+   * @deprecated Deprecated in C++20.
+   * Use `is_standard_layout && is_trivial` instead.
+   */
+  // Could use is_standard_layout && is_trivial instead of the builtin.
+  template<typename _Tp>
+    struct
+    _GLIBCXX20_DEPRECATED("use is_standard_layout && is_trivial instead")
+    is_pod
+    : public integral_constant<bool, __is_pod(_Tp)>
+    {
+      static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
+	"template argument must be a complete class or an unbounded array");
+    };
+
+  /** is_literal_type
+   * @deprecated Deprecated in C++17, removed in C++20.
+   * The idea of a literal type isn't useful.
+   */
+  template<typename _Tp>
+    struct
+    _GLIBCXX17_DEPRECATED
+    is_literal_type
+    : public integral_constant<bool, __is_literal_type(_Tp)>
+    {
+      static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
+	"template argument must be a complete class or an unbounded array");
+    };
+
+  /// is_empty
+  template<typename _Tp>
+    struct is_empty
+    : public integral_constant<bool, __is_empty(_Tp)>
+    { };
+
+  /// is_polymorphic
+  template<typename _Tp>
+    struct is_polymorphic
+    : public integral_constant<bool, __is_polymorphic(_Tp)>
+    { };
+
+#if __cplusplus >= 201402L
+#define __cpp_lib_is_final 201402L
+  /// is_final
+  /// @since C++14
+  template<typename _Tp>
+    struct is_final
+    : public integral_constant<bool, __is_final(_Tp)>
+    { };
+#endif
+
+  /// is_abstract
+  template<typename _Tp>
+    struct is_abstract
+    : public integral_constant<bool, __is_abstract(_Tp)>
+    { };
+
+  /// @cond undocumented
+  template<typename _Tp,
+	   bool = is_arithmetic<_Tp>::value>
+    struct __is_signed_helper
+    : public false_type { };
+
+  template<typename _Tp>
+    struct __is_signed_helper<_Tp, true>
+    : public integral_constant<bool, _Tp(-1) < _Tp(0)>
+    { };
+  /// @endcond
+
+  /// is_signed
+  template<typename _Tp>
+    struct is_signed
+    : public __is_signed_helper<_Tp>::type
+    { };
+
+  /// is_unsigned
+  template<typename _Tp>
+    struct is_unsigned
+    : public __and_<is_arithmetic<_Tp>, __not_<is_signed<_Tp>>>
+    { };
+
+  /// @cond undocumented
+  template<typename _Tp, typename _Up = _Tp&&>
+    _Up
+    __declval(int);
+
+  template<typename _Tp>
+    _Tp
+    __declval(long);
+  /// @endcond
+
+  template<typename _Tp>
+    auto declval() noexcept -> decltype(__declval<_Tp>(0));
+
+  template<typename, unsigned = 0>
+    struct extent;
+
+  template<typename>
+    struct remove_all_extents;
+
+  /// @cond undocumented
+  template<typename _Tp>
+    struct __is_array_known_bounds
+    : public integral_constant<bool, (extent<_Tp>::value > 0)>
+    { };
+
+  template<typename _Tp>
+    struct __is_array_unknown_bounds
+    : public __and_<is_array<_Tp>, __not_<extent<_Tp>>>
+    { };
+
+  // Destructible and constructible type properties.
+
+  // In N3290 is_destructible does not say anything about function
+  // types and abstract types, see LWG 2049. This implementation
+  // describes function types as non-destructible and all complete
+  // object types as destructible, iff the explicit destructor
+  // call expression is wellformed.
+  struct __do_is_destructible_impl
+  {
+    template<typename _Tp, typename = decltype(declval<_Tp&>().~_Tp())>
+      static true_type __test(int);
+
+    template<typename>
+      static false_type __test(...);
+  };
+
+  template<typename _Tp>
+    struct __is_destructible_impl
+    : public __do_is_destructible_impl
+    {
+      typedef decltype(__test<_Tp>(0)) type;
+    };
+
+  template<typename _Tp,
+           bool = __or_<is_void<_Tp>,
+                        __is_array_unknown_bounds<_Tp>,
+                        is_function<_Tp>>::value,
+           bool = __or_<is_reference<_Tp>, is_scalar<_Tp>>::value>
+    struct __is_destructible_safe;
+
+  template<typename _Tp>
+    struct __is_destructible_safe<_Tp, false, false>
+    : public __is_destructible_impl<typename
+               remove_all_extents<_Tp>::type>::type
+    { };
+
+  template<typename _Tp>
+    struct __is_destructible_safe<_Tp, true, false>
+    : public false_type { };
+
+  template<typename _Tp>
+    struct __is_destructible_safe<_Tp, false, true>
+    : public true_type { };
+  /// @endcond
+
+  /// is_destructible
+  template<typename _Tp>
+    struct is_destructible
+    : public __is_destructible_safe<_Tp>::type
+    {
+      static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
+	"template argument must be a complete class or an unbounded array");
+    };
+
+  /// @cond undocumented
+
+  // is_nothrow_destructible requires that is_destructible is
+  // satisfied as well.  We realize that by mimicing the
+  // implementation of is_destructible but refer to noexcept(expr)
+  // instead of decltype(expr).
+  struct __do_is_nt_destructible_impl
+  {
+    template<typename _Tp>
+      static __bool_constant<noexcept(declval<_Tp&>().~_Tp())>
+      __test(int);
+
+    template<typename>
+      static false_type __test(...);
+  };
+
+  template<typename _Tp>
+    struct __is_nt_destructible_impl
+    : public __do_is_nt_destructible_impl
+    {
+      typedef decltype(__test<_Tp>(0)) type;
+    };
+
+  template<typename _Tp,
+           bool = __or_<is_void<_Tp>,
+                        __is_array_unknown_bounds<_Tp>,
+                        is_function<_Tp>>::value,
+           bool = __or_<is_reference<_Tp>, is_scalar<_Tp>>::value>
+    struct __is_nt_destructible_safe;
+
+  template<typename _Tp>
+    struct __is_nt_destructible_safe<_Tp, false, false>
+    : public __is_nt_destructible_impl<typename
+               remove_all_extents<_Tp>::type>::type
+    { };
+
+  template<typename _Tp>
+    struct __is_nt_destructible_safe<_Tp, true, false>
+    : public false_type { };
+
+  template<typename _Tp>
+    struct __is_nt_destructible_safe<_Tp, false, true>
+    : public true_type { };
+  /// @endcond
+
+  /// is_nothrow_destructible
+  template<typename _Tp>
+    struct is_nothrow_destructible
+    : public __is_nt_destructible_safe<_Tp>::type
+    {
+      static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
+	"template argument must be a complete class or an unbounded array");
+    };
+
+  /// @cond undocumented
+  template<typename _Tp, typename... _Args>
+    struct __is_constructible_impl
+    : public __bool_constant<__is_constructible(_Tp, _Args...)>
+    { };
+  /// @endcond
+
+  /// is_constructible
+  template<typename _Tp, typename... _Args>
+    struct is_constructible
+      : public __is_constructible_impl<_Tp, _Args...>
+    {
+      static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
+	"template argument must be a complete class or an unbounded array");
+    };
+
+  /// is_default_constructible
+  template<typename _Tp>
+    struct is_default_constructible
+    : public __is_constructible_impl<_Tp>::type
+    {
+      static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
+	"template argument must be a complete class or an unbounded array");
+    };
+
+  /// @cond undocumented
+  template<typename _Tp, bool = __is_referenceable<_Tp>::value>
+    struct __is_copy_constructible_impl;
+
+  template<typename _Tp>
+    struct __is_copy_constructible_impl<_Tp, false>
+    : public false_type { };
+
+  template<typename _Tp>
+    struct __is_copy_constructible_impl<_Tp, true>
+    : public __is_constructible_impl<_Tp, const _Tp&>
+    { };
+  /// @endcond
+
+  /// is_copy_constructible
+  template<typename _Tp>
+    struct is_copy_constructible
+    : public __is_copy_constructible_impl<_Tp>
+    {
+      static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
+	"template argument must be a complete class or an unbounded array");
+    };
+
+  /// @cond undocumented
+  template<typename _Tp, bool = __is_referenceable<_Tp>::value>
+    struct __is_move_constructible_impl;
+
+  template<typename _Tp>
+    struct __is_move_constructible_impl<_Tp, false>
+    : public false_type { };
+
+  template<typename _Tp>
+    struct __is_move_constructible_impl<_Tp, true>
+    : public __is_constructible_impl<_Tp, _Tp&&>
+    { };
+  /// @endcond
+
+  /// is_move_constructible
+  template<typename _Tp>
+    struct is_move_constructible
+    : public __is_move_constructible_impl<_Tp>
+    {
+      static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
+	"template argument must be a complete class or an unbounded array");
+    };
+
+  /// @cond undocumented
+  template<typename _Tp, typename... _Args>
+    using __is_nothrow_constructible_impl
+      = __bool_constant<__is_nothrow_constructible(_Tp, _Args...)>;
+  /// @endcond
+
+  /// is_nothrow_constructible
+  template<typename _Tp, typename... _Args>
+    struct is_nothrow_constructible
+    : public __is_nothrow_constructible_impl<_Tp, _Args...>::type
+    {
+      static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
+	"template argument must be a complete class or an unbounded array");
+    };
+
+  /// is_nothrow_default_constructible
+  template<typename _Tp>
+    struct is_nothrow_default_constructible
+    : public __bool_constant<__is_nothrow_constructible(_Tp)>
+    {
+      static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
+	"template argument must be a complete class or an unbounded array");
+    };
+
+  /// @cond undocumented
+  template<typename _Tp, bool = __is_referenceable<_Tp>::value>
+    struct __is_nothrow_copy_constructible_impl;
+
+  template<typename _Tp>
+    struct __is_nothrow_copy_constructible_impl<_Tp, false>
+    : public false_type { };
+
+  template<typename _Tp>
+    struct __is_nothrow_copy_constructible_impl<_Tp, true>
+    : public __is_nothrow_constructible_impl<_Tp, const _Tp&>
+    { };
+  /// @endcond
+
+  /// is_nothrow_copy_constructible
+  template<typename _Tp>
+    struct is_nothrow_copy_constructible
+    : public __is_nothrow_copy_constructible_impl<_Tp>::type
+    {
+      static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
+	"template argument must be a complete class or an unbounded array");
+    };
+
+  /// @cond undocumented
+  template<typename _Tp, bool = __is_referenceable<_Tp>::value>
+    struct __is_nothrow_move_constructible_impl;
+
+  template<typename _Tp>
+    struct __is_nothrow_move_constructible_impl<_Tp, false>
+    : public false_type { };
+
+  template<typename _Tp>
+    struct __is_nothrow_move_constructible_impl<_Tp, true>
+    : public __is_nothrow_constructible_impl<_Tp, _Tp&&>
+    { };
+  /// @endcond
+
+  /// is_nothrow_move_constructible
+  template<typename _Tp>
+    struct is_nothrow_move_constructible
+    : public __is_nothrow_move_constructible_impl<_Tp>::type
+    {
+      static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
+	"template argument must be a complete class or an unbounded array");
+    };
+
+  /// is_assignable
+  template<typename _Tp, typename _Up>
+    struct is_assignable
+    : public __bool_constant<__is_assignable(_Tp, _Up)>
+    {
+      static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
+	"template argument must be a complete class or an unbounded array");
+    };
+
+  template<typename _Tp, bool = __is_referenceable<_Tp>::value>
+    struct __is_copy_assignable_impl;
+
+  template<typename _Tp>
+    struct __is_copy_assignable_impl<_Tp, false>
+    : public false_type { };
+
+  template<typename _Tp>
+    struct __is_copy_assignable_impl<_Tp, true>
+    : public __bool_constant<__is_assignable(_Tp&, const _Tp&)>
+    { };
+
+  /// is_copy_assignable
+  template<typename _Tp>
+    struct is_copy_assignable
+    : public __is_copy_assignable_impl<_Tp>::type
+    {
+      static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
+	"template argument must be a complete class or an unbounded array");
+    };
+
+  template<typename _Tp, bool = __is_referenceable<_Tp>::value>
+    struct __is_move_assignable_impl;
+
+  template<typename _Tp>
+    struct __is_move_assignable_impl<_Tp, false>
+    : public false_type { };
+
+  template<typename _Tp>
+    struct __is_move_assignable_impl<_Tp, true>
+    : public __bool_constant<__is_assignable(_Tp&, _Tp&&)>
+    { };
+
+  /// is_move_assignable
+  template<typename _Tp>
+    struct is_move_assignable
+    : public __is_move_assignable_impl<_Tp>::type
+    {
+      static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
+	"template argument must be a complete class or an unbounded array");
+    };
+
+  template<typename _Tp, typename _Up>
+    using __is_nothrow_assignable_impl
+      = __bool_constant<__is_nothrow_assignable(_Tp, _Up)>;
+
+  /// is_nothrow_assignable
+  template<typename _Tp, typename _Up>
+    struct is_nothrow_assignable
+    : public __is_nothrow_assignable_impl<_Tp, _Up>
+    {
+      static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
+	"template argument must be a complete class or an unbounded array");
+    };
+
+  template<typename _Tp, bool = __is_referenceable<_Tp>::value>
+    struct __is_nt_copy_assignable_impl;
+
+  template<typename _Tp>
+    struct __is_nt_copy_assignable_impl<_Tp, false>
+    : public false_type { };
+
+  template<typename _Tp>
+    struct __is_nt_copy_assignable_impl<_Tp, true>
+    : public __is_nothrow_assignable_impl<_Tp&, const _Tp&>
+    { };
+
+  /// is_nothrow_copy_assignable
+  template<typename _Tp>
+    struct is_nothrow_copy_assignable
+    : public __is_nt_copy_assignable_impl<_Tp>
+    {
+      static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
+	"template argument must be a complete class or an unbounded array");
+    };
+
+  template<typename _Tp, bool = __is_referenceable<_Tp>::value>
+    struct __is_nt_move_assignable_impl;
+
+  template<typename _Tp>
+    struct __is_nt_move_assignable_impl<_Tp, false>
+    : public false_type { };
+
+  template<typename _Tp>
+    struct __is_nt_move_assignable_impl<_Tp, true>
+    : public __is_nothrow_assignable_impl<_Tp&, _Tp&&>
+    { };
+
+  /// is_nothrow_move_assignable
+  template<typename _Tp>
+    struct is_nothrow_move_assignable
+    : public __is_nt_move_assignable_impl<_Tp>
+    {
+      static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
+	"template argument must be a complete class or an unbounded array");
+    };
+
+  /// is_trivially_constructible
+  template<typename _Tp, typename... _Args>
+    struct is_trivially_constructible
+    : public __bool_constant<__is_trivially_constructible(_Tp, _Args...)>
+    {
+      static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
+	"template argument must be a complete class or an unbounded array");
+    };
+
+  /// is_trivially_default_constructible
+  template<typename _Tp>
+    struct is_trivially_default_constructible
+    : public __bool_constant<__is_trivially_constructible(_Tp)>
+    {
+      static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
+	"template argument must be a complete class or an unbounded array");
+    };
+
+  struct __do_is_implicitly_default_constructible_impl
+  {
+    template <typename _Tp>
+    static void __helper(const _Tp&);
+
+    template <typename _Tp>
+    static true_type __test(const _Tp&,
+                            decltype(__helper<const _Tp&>({}))* = 0);
+
+    static false_type __test(...);
+  };
+
+  template<typename _Tp>
+    struct __is_implicitly_default_constructible_impl
+    : public __do_is_implicitly_default_constructible_impl
+    {
+      typedef decltype(__test(declval<_Tp>())) type;
+    };
+
+  template<typename _Tp>
+    struct __is_implicitly_default_constructible_safe
+    : public __is_implicitly_default_constructible_impl<_Tp>::type
+    { };
+
+  template <typename _Tp>
+    struct __is_implicitly_default_constructible
+    : public __and_<__is_constructible_impl<_Tp>,
+		    __is_implicitly_default_constructible_safe<_Tp>>
+    { };
+
+  template<typename _Tp, bool = __is_referenceable<_Tp>::value>
+    struct __is_trivially_copy_constructible_impl;
+
+  template<typename _Tp>
+    struct __is_trivially_copy_constructible_impl<_Tp, false>
+    : public false_type { };
+
+  template<typename _Tp>
+    struct __is_trivially_copy_constructible_impl<_Tp, true>
+    : public __and_<__is_copy_constructible_impl<_Tp>,
+		    integral_constant<bool,
+			__is_trivially_constructible(_Tp, const _Tp&)>>
+    { };
+
+  /// is_trivially_copy_constructible
+  template<typename _Tp>
+    struct is_trivially_copy_constructible
+    : public __is_trivially_copy_constructible_impl<_Tp>
+    {
+      static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
+	"template argument must be a complete class or an unbounded array");
+    };
+
+  template<typename _Tp, bool = __is_referenceable<_Tp>::value>
+    struct __is_trivially_move_constructible_impl;
+
+  template<typename _Tp>
+    struct __is_trivially_move_constructible_impl<_Tp, false>
+    : public false_type { };
+
+  template<typename _Tp>
+    struct __is_trivially_move_constructible_impl<_Tp, true>
+    : public __and_<__is_move_constructible_impl<_Tp>,
+		    integral_constant<bool,
+			__is_trivially_constructible(_Tp, _Tp&&)>>
+    { };
+
+  /// is_trivially_move_constructible
+  template<typename _Tp>
+    struct is_trivially_move_constructible
+    : public __is_trivially_move_constructible_impl<_Tp>
+    {
+      static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
+	"template argument must be a complete class or an unbounded array");
+    };
+
+  /// is_trivially_assignable
+  template<typename _Tp, typename _Up>
+    struct is_trivially_assignable
+    : public __bool_constant<__is_trivially_assignable(_Tp, _Up)>
+    {
+      static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
+	"template argument must be a complete class or an unbounded array");
+    };
+
+  template<typename _Tp, bool = __is_referenceable<_Tp>::value>
+    struct __is_trivially_copy_assignable_impl;
+
+  template<typename _Tp>
+    struct __is_trivially_copy_assignable_impl<_Tp, false>
+    : public false_type { };
+
+  template<typename _Tp>
+    struct __is_trivially_copy_assignable_impl<_Tp, true>
+    : public __bool_constant<__is_trivially_assignable(_Tp&, const _Tp&)>
+    { };
+
+  /// is_trivially_copy_assignable
+  template<typename _Tp>
+    struct is_trivially_copy_assignable
+    : public __is_trivially_copy_assignable_impl<_Tp>
+    {
+      static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
+	"template argument must be a complete class or an unbounded array");
+    };
+
+  template<typename _Tp, bool = __is_referenceable<_Tp>::value>
+    struct __is_trivially_move_assignable_impl;
+
+  template<typename _Tp>
+    struct __is_trivially_move_assignable_impl<_Tp, false>
+    : public false_type { };
+
+  template<typename _Tp>
+    struct __is_trivially_move_assignable_impl<_Tp, true>
+    : public __bool_constant<__is_trivially_assignable(_Tp&, _Tp&&)>
+    { };
+
+  /// is_trivially_move_assignable
+  template<typename _Tp>
+    struct is_trivially_move_assignable
+    : public __is_trivially_move_assignable_impl<_Tp>
+    {
+      static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
+	"template argument must be a complete class or an unbounded array");
+    };
+
+  /// is_trivially_destructible
+  template<typename _Tp>
+    struct is_trivially_destructible
+    : public __and_<__is_destructible_safe<_Tp>,
+		    __bool_constant<__has_trivial_destructor(_Tp)>>
+    {
+      static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
+	"template argument must be a complete class or an unbounded array");
+    };
+
+
+  /// has_virtual_destructor
+  template<typename _Tp>
+    struct has_virtual_destructor
+    : public integral_constant<bool, __has_virtual_destructor(_Tp)>
+    {
+      static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
+	"template argument must be a complete class or an unbounded array");
+    };
+
+
+  // type property queries.
+
+  /// alignment_of
+  template<typename _Tp>
+    struct alignment_of
+    : public integral_constant<std::size_t, alignof(_Tp)>
+    {
+      static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
+	"template argument must be a complete class or an unbounded array");
+    };
+
+  /// rank
+  template<typename>
+    struct rank
+    : public integral_constant<std::size_t, 0> { };
+
+  template<typename _Tp, std::size_t _Size>
+    struct rank<_Tp[_Size]>
+    : public integral_constant<std::size_t, 1 + rank<_Tp>::value> { };
+
+  template<typename _Tp>
+    struct rank<_Tp[]>
+    : public integral_constant<std::size_t, 1 + rank<_Tp>::value> { };
+
+  /// extent
+  template<typename, unsigned _Uint>
+    struct extent
+    : public integral_constant<std::size_t, 0> { };
+
+  template<typename _Tp, unsigned _Uint, std::size_t _Size>
+    struct extent<_Tp[_Size], _Uint>
+    : public integral_constant<std::size_t,
+			       _Uint == 0 ? _Size : extent<_Tp,
+							   _Uint - 1>::value>
+    { };
+
+  template<typename _Tp, unsigned _Uint>
+    struct extent<_Tp[], _Uint>
+    : public integral_constant<std::size_t,
+			       _Uint == 0 ? 0 : extent<_Tp,
+						       _Uint - 1>::value>
+    { };
+
+
+  // Type relations.
+
+  /// is_same
+  template<typename _Tp, typename _Up>
+    struct is_same
+#ifdef _GLIBCXX_HAVE_BUILTIN_IS_SAME
+    : public integral_constant<bool, __is_same(_Tp, _Up)>
+#else
+    : public false_type
+#endif
+    { };
+
+#ifndef _GLIBCXX_HAVE_BUILTIN_IS_SAME
+  template<typename _Tp>
+    struct is_same<_Tp, _Tp>
+    : public true_type
+    { };
+#endif
+
+  /// is_base_of
+  template<typename _Base, typename _Derived>
+    struct is_base_of
+    : public integral_constant<bool, __is_base_of(_Base, _Derived)>
+    { };
+
+  template<typename _From, typename _To,
+           bool = __or_<is_void<_From>, is_function<_To>,
+                        is_array<_To>>::value>
+    struct __is_convertible_helper
+    {
+      typedef typename is_void<_To>::type type;
+    };
+
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wctor-dtor-privacy"
+  template<typename _From, typename _To>
+    class __is_convertible_helper<_From, _To, false>
+    {
+      template<typename _To1>
+	static void __test_aux(_To1) noexcept;
+
+      template<typename _From1, typename _To1,
+	       typename = decltype(__test_aux<_To1>(std::declval<_From1>()))>
+	static true_type
+	__test(int);
+
+      template<typename, typename>
+	static false_type
+	__test(...);
+
+    public:
+      typedef decltype(__test<_From, _To>(0)) type;
+    };
+#pragma GCC diagnostic pop
+
+  /// is_convertible
+  template<typename _From, typename _To>
+    struct is_convertible
+    : public __is_convertible_helper<_From, _To>::type
+    { };
+
+  // helper trait for unique_ptr<T[]>, shared_ptr<T[]>, and span<T, N>
+  template<typename _ToElementType, typename _FromElementType>
+    using __is_array_convertible
+      = is_convertible<_FromElementType(*)[], _ToElementType(*)[]>;
+
+  template<typename _From, typename _To,
+           bool = __or_<is_void<_From>, is_function<_To>,
+                        is_array<_To>>::value>
+    struct __is_nt_convertible_helper
+    : is_void<_To>
+    { };
+
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wctor-dtor-privacy"
+  template<typename _From, typename _To>
+    class __is_nt_convertible_helper<_From, _To, false>
+    {
+      template<typename _To1>
+	static void __test_aux(_To1) noexcept;
+
+      template<typename _From1, typename _To1>
+	static
+	__bool_constant<noexcept(__test_aux<_To1>(std::declval<_From1>()))>
+	__test(int);
+
+      template<typename, typename>
+	static false_type
+	__test(...);
+
+    public:
+      using type = decltype(__test<_From, _To>(0));
+    };
+#pragma GCC diagnostic pop
+
+  // is_nothrow_convertible for C++11
+  template<typename _From, typename _To>
+    struct __is_nothrow_convertible
+    : public __is_nt_convertible_helper<_From, _To>::type
+    { };
+
+#if __cplusplus > 201703L
+#define __cpp_lib_is_nothrow_convertible 201806L
+  /// is_nothrow_convertible
+  template<typename _From, typename _To>
+    struct is_nothrow_convertible
+    : public __is_nt_convertible_helper<_From, _To>::type
+    { };
+
+  /// is_nothrow_convertible_v
+  template<typename _From, typename _To>
+    inline constexpr bool is_nothrow_convertible_v
+      = is_nothrow_convertible<_From, _To>::value;
+#endif // C++2a
+
+  // Const-volatile modifications.
+
+  /// remove_const
+  template<typename _Tp>
+    struct remove_const
+    { typedef _Tp     type; };
+
+  template<typename _Tp>
+    struct remove_const<_Tp const>
+    { typedef _Tp     type; };
+
+  /// remove_volatile
+  template<typename _Tp>
+    struct remove_volatile
+    { typedef _Tp     type; };
+
+  template<typename _Tp>
+    struct remove_volatile<_Tp volatile>
+    { typedef _Tp     type; };
+
+  /// remove_cv
+  template<typename _Tp>
+    struct remove_cv
+    { using type = _Tp; };
+
+  template<typename _Tp>
+    struct remove_cv<const _Tp>
+    { using type = _Tp; };
+
+  template<typename _Tp>
+    struct remove_cv<volatile _Tp>
+    { using type = _Tp; };
+
+  template<typename _Tp>
+    struct remove_cv<const volatile _Tp>
+    { using type = _Tp; };
+
+  /// add_const
+  template<typename _Tp>
+    struct add_const
+    { typedef _Tp const     type; };
+
+  /// add_volatile
+  template<typename _Tp>
+    struct add_volatile
+    { typedef _Tp volatile     type; };
+
+  /// add_cv
+  template<typename _Tp>
+    struct add_cv
+    {
+      typedef typename
+      add_const<typename add_volatile<_Tp>::type>::type     type;
+    };
+
+#if __cplusplus > 201103L
+
+#define __cpp_lib_transformation_trait_aliases 201304L
+
+  /// Alias template for remove_const
+  template<typename _Tp>
+    using remove_const_t = typename remove_const<_Tp>::type;
+
+  /// Alias template for remove_volatile
+  template<typename _Tp>
+    using remove_volatile_t = typename remove_volatile<_Tp>::type;
+
+  /// Alias template for remove_cv
+  template<typename _Tp>
+    using remove_cv_t = typename remove_cv<_Tp>::type;
+
+  /// Alias template for add_const
+  template<typename _Tp>
+    using add_const_t = typename add_const<_Tp>::type;
+
+  /// Alias template for add_volatile
+  template<typename _Tp>
+    using add_volatile_t = typename add_volatile<_Tp>::type;
+
+  /// Alias template for add_cv
+  template<typename _Tp>
+    using add_cv_t = typename add_cv<_Tp>::type;
+#endif
+
+  // Reference transformations.
+
+  /// remove_reference
+  template<typename _Tp>
+    struct remove_reference
+    { typedef _Tp   type; };
+
+  template<typename _Tp>
+    struct remove_reference<_Tp&>
+    { typedef _Tp   type; };
+
+  template<typename _Tp>
+    struct remove_reference<_Tp&&>
+    { typedef _Tp   type; };
+
+  template<typename _Tp, bool = __is_referenceable<_Tp>::value>
+    struct __add_lvalue_reference_helper
+    { typedef _Tp   type; };
+
+  template<typename _Tp>
+    struct __add_lvalue_reference_helper<_Tp, true>
+    { typedef _Tp&   type; };
+
+  /// add_lvalue_reference
+  template<typename _Tp>
+    struct add_lvalue_reference
+    : public __add_lvalue_reference_helper<_Tp>
+    { };
+
+  template<typename _Tp, bool = __is_referenceable<_Tp>::value>
+    struct __add_rvalue_reference_helper
+    { typedef _Tp   type; };
+
+  template<typename _Tp>
+    struct __add_rvalue_reference_helper<_Tp, true>
+    { typedef _Tp&&   type; };
+
+  /// add_rvalue_reference
+  template<typename _Tp>
+    struct add_rvalue_reference
+    : public __add_rvalue_reference_helper<_Tp>
+    { };
+
+#if __cplusplus > 201103L
+  /// Alias template for remove_reference
+  template<typename _Tp>
+    using remove_reference_t = typename remove_reference<_Tp>::type;
+
+  /// Alias template for add_lvalue_reference
+  template<typename _Tp>
+    using add_lvalue_reference_t = typename add_lvalue_reference<_Tp>::type;
+
+  /// Alias template for add_rvalue_reference
+  template<typename _Tp>
+    using add_rvalue_reference_t = typename add_rvalue_reference<_Tp>::type;
+#endif
+
+  // Sign modifications.
+
+  /// @cond undocumented
+
+  // Utility for constructing identically cv-qualified types.
+  template<typename _Unqualified, bool _IsConst, bool _IsVol>
+    struct __cv_selector;
+
+  template<typename _Unqualified>
+    struct __cv_selector<_Unqualified, false, false>
+    { typedef _Unqualified __type; };
+
+  template<typename _Unqualified>
+    struct __cv_selector<_Unqualified, false, true>
+    { typedef volatile _Unqualified __type; };
+
+  template<typename _Unqualified>
+    struct __cv_selector<_Unqualified, true, false>
+    { typedef const _Unqualified __type; };
+
+  template<typename _Unqualified>
+    struct __cv_selector<_Unqualified, true, true>
+    { typedef const volatile _Unqualified __type; };
+
+  template<typename _Qualified, typename _Unqualified,
+	   bool _IsConst = is_const<_Qualified>::value,
+	   bool _IsVol = is_volatile<_Qualified>::value>
+    class __match_cv_qualifiers
+    {
+      typedef __cv_selector<_Unqualified, _IsConst, _IsVol> __match;
+
+    public:
+      typedef typename __match::__type __type;
+    };
+
+  // Utility for finding the unsigned versions of signed integral types.
+  template<typename _Tp>
+    struct __make_unsigned
+    { typedef _Tp __type; };
+
+  template<>
+    struct __make_unsigned<char>
+    { typedef unsigned char __type; };
+
+  template<>
+    struct __make_unsigned<signed char>
+    { typedef unsigned char __type; };
+
+  template<>
+    struct __make_unsigned<short>
+    { typedef unsigned short __type; };
+
+  template<>
+    struct __make_unsigned<int>
+    { typedef unsigned int __type; };
+
+  template<>
+    struct __make_unsigned<long>
+    { typedef unsigned long __type; };
+
+  template<>
+    struct __make_unsigned<long long>
+    { typedef unsigned long long __type; };
+
+#if defined(__GLIBCXX_TYPE_INT_N_0)
+  __extension__
+  template<>
+    struct __make_unsigned<__GLIBCXX_TYPE_INT_N_0>
+    { typedef unsigned __GLIBCXX_TYPE_INT_N_0 __type; };
+#endif
+#if defined(__GLIBCXX_TYPE_INT_N_1)
+  __extension__
+  template<>
+    struct __make_unsigned<__GLIBCXX_TYPE_INT_N_1>
+    { typedef unsigned __GLIBCXX_TYPE_INT_N_1 __type; };
+#endif
+#if defined(__GLIBCXX_TYPE_INT_N_2)
+  __extension__
+  template<>
+    struct __make_unsigned<__GLIBCXX_TYPE_INT_N_2>
+    { typedef unsigned __GLIBCXX_TYPE_INT_N_2 __type; };
+#endif
+#if defined(__GLIBCXX_TYPE_INT_N_3)
+  __extension__
+  template<>
+    struct __make_unsigned<__GLIBCXX_TYPE_INT_N_3>
+    { typedef unsigned __GLIBCXX_TYPE_INT_N_3 __type; };
+#endif
+
+  // Select between integral and enum: not possible to be both.
+  template<typename _Tp,
+	   bool _IsInt = is_integral<_Tp>::value,
+	   bool _IsEnum = is_enum<_Tp>::value>
+    class __make_unsigned_selector;
+
+  template<typename _Tp>
+    class __make_unsigned_selector<_Tp, true, false>
+    {
+      using __unsigned_type
+	= typename __make_unsigned<__remove_cv_t<_Tp>>::__type;
+
+    public:
+      using __type
+	= typename __match_cv_qualifiers<_Tp, __unsigned_type>::__type;
+    };
+
+  class __make_unsigned_selector_base
+  {
+  protected:
+    template<typename...> struct _List { };
+
+    template<typename _Tp, typename... _Up>
+      struct _List<_Tp, _Up...> : _List<_Up...>
+      { static constexpr size_t __size = sizeof(_Tp); };
+
+    template<size_t _Sz, typename _Tp, bool = (_Sz <= _Tp::__size)>
+      struct __select;
+
+    template<size_t _Sz, typename _Uint, typename... _UInts>
+      struct __select<_Sz, _List<_Uint, _UInts...>, true>
+      { using __type = _Uint; };
+
+    template<size_t _Sz, typename _Uint, typename... _UInts>
+      struct __select<_Sz, _List<_Uint, _UInts...>, false>
+      : __select<_Sz, _List<_UInts...>>
+      { };
+  };
+
+  // Choose unsigned integer type with the smallest rank and same size as _Tp
+  template<typename _Tp>
+    class __make_unsigned_selector<_Tp, false, true>
+    : __make_unsigned_selector_base
+    {
+      // With -fshort-enums, an enum may be as small as a char.
+      using _UInts = _List<unsigned char, unsigned short, unsigned int,
+			   unsigned long, unsigned long long>;
+
+      using __unsigned_type = typename __select<sizeof(_Tp), _UInts>::__type;
+
+    public:
+      using __type
+	= typename __match_cv_qualifiers<_Tp, __unsigned_type>::__type;
+    };
+
+  // wchar_t, char8_t, char16_t and char32_t are integral types but are
+  // neither signed integer types nor unsigned integer types, so must be
+  // transformed to the unsigned integer type with the smallest rank.
+  // Use the partial specialization for enumeration types to do that.
+  template<>
+    struct __make_unsigned<wchar_t>
+    {
+      using __type
+	= typename __make_unsigned_selector<wchar_t, false, true>::__type;
+    };
+
+#ifdef _GLIBCXX_USE_CHAR8_T
+  template<>
+    struct __make_unsigned<char8_t>
+    {
+      using __type
+	= typename __make_unsigned_selector<char8_t, false, true>::__type;
+    };
+#endif
+
+  template<>
+    struct __make_unsigned<char16_t>
+    {
+      using __type
+	= typename __make_unsigned_selector<char16_t, false, true>::__type;
+    };
+
+  template<>
+    struct __make_unsigned<char32_t>
+    {
+      using __type
+	= typename __make_unsigned_selector<char32_t, false, true>::__type;
+    };
+  /// @endcond
+
+  // Given an integral/enum type, return the corresponding unsigned
+  // integer type.
+  // Primary template.
+  /// make_unsigned
+  template<typename _Tp>
+    struct make_unsigned
+    { typedef typename __make_unsigned_selector<_Tp>::__type type; };
+
+  // Integral, but don't define.
+  template<>
+    struct make_unsigned<bool>;
+
+  /// @cond undocumented
+
+  // Utility for finding the signed versions of unsigned integral types.
+  template<typename _Tp>
+    struct __make_signed
+    { typedef _Tp __type; };
+
+  template<>
+    struct __make_signed<char>
+    { typedef signed char __type; };
+
+  template<>
+    struct __make_signed<unsigned char>
+    { typedef signed char __type; };
+
+  template<>
+    struct __make_signed<unsigned short>
+    { typedef signed short __type; };
+
+  template<>
+    struct __make_signed<unsigned int>
+    { typedef signed int __type; };
+
+  template<>
+    struct __make_signed<unsigned long>
+    { typedef signed long __type; };
+
+  template<>
+    struct __make_signed<unsigned long long>
+    { typedef signed long long __type; };
+
+#if defined(__GLIBCXX_TYPE_INT_N_0)
+  __extension__
+  template<>
+    struct __make_signed<unsigned __GLIBCXX_TYPE_INT_N_0>
+    { typedef __GLIBCXX_TYPE_INT_N_0 __type; };
+#endif
+#if defined(__GLIBCXX_TYPE_INT_N_1)
+  __extension__
+  template<>
+    struct __make_signed<unsigned __GLIBCXX_TYPE_INT_N_1>
+    { typedef __GLIBCXX_TYPE_INT_N_1 __type; };
+#endif
+#if defined(__GLIBCXX_TYPE_INT_N_2)
+  __extension__
+  template<>
+    struct __make_signed<unsigned __GLIBCXX_TYPE_INT_N_2>
+    { typedef __GLIBCXX_TYPE_INT_N_2 __type; };
+#endif
+#if defined(__GLIBCXX_TYPE_INT_N_3)
+  __extension__
+  template<>
+    struct __make_signed<unsigned __GLIBCXX_TYPE_INT_N_3>
+    { typedef __GLIBCXX_TYPE_INT_N_3 __type; };
+#endif
+
+  // Select between integral and enum: not possible to be both.
+  template<typename _Tp,
+	   bool _IsInt = is_integral<_Tp>::value,
+	   bool _IsEnum = is_enum<_Tp>::value>
+    class __make_signed_selector;
+
+  template<typename _Tp>
+    class __make_signed_selector<_Tp, true, false>
+    {
+      using __signed_type
+	= typename __make_signed<__remove_cv_t<_Tp>>::__type;
+
+    public:
+      using __type
+	= typename __match_cv_qualifiers<_Tp, __signed_type>::__type;
+    };
+
+  // Choose signed integer type with the smallest rank and same size as _Tp
+  template<typename _Tp>
+    class __make_signed_selector<_Tp, false, true>
+    {
+      typedef typename __make_unsigned_selector<_Tp>::__type __unsigned_type;
+
+    public:
+      typedef typename __make_signed_selector<__unsigned_type>::__type __type;
+    };
+
+  // wchar_t, char16_t and char32_t are integral types but are neither
+  // signed integer types nor unsigned integer types, so must be
+  // transformed to the signed integer type with the smallest rank.
+  // Use the partial specialization for enumeration types to do that.
+  template<>
+    struct __make_signed<wchar_t>
+    {
+      using __type
+	= typename __make_signed_selector<wchar_t, false, true>::__type;
+    };
+
+#if defined(_GLIBCXX_USE_CHAR8_T)
+  template<>
+    struct __make_signed<char8_t>
+    {
+      using __type
+	= typename __make_signed_selector<char8_t, false, true>::__type;
+    };
+#endif
+
+  template<>
+    struct __make_signed<char16_t>
+    {
+      using __type
+	= typename __make_signed_selector<char16_t, false, true>::__type;
+    };
+
+  template<>
+    struct __make_signed<char32_t>
+    {
+      using __type
+	= typename __make_signed_selector<char32_t, false, true>::__type;
+    };
+  /// @endcond
+
+  // Given an integral/enum type, return the corresponding signed
+  // integer type.
+  // Primary template.
+  /// make_signed
+  template<typename _Tp>
+    struct make_signed
+    { typedef typename __make_signed_selector<_Tp>::__type type; };
+
+  // Integral, but don't define.
+  template<>
+    struct make_signed<bool>;
+
+#if __cplusplus > 201103L
+  /// Alias template for make_signed
+  template<typename _Tp>
+    using make_signed_t = typename make_signed<_Tp>::type;
+
+  /// Alias template for make_unsigned
+  template<typename _Tp>
+    using make_unsigned_t = typename make_unsigned<_Tp>::type;
+#endif
+
+  // Array modifications.
+
+  /// remove_extent
+  template<typename _Tp>
+    struct remove_extent
+    { typedef _Tp     type; };
+
+  template<typename _Tp, std::size_t _Size>
+    struct remove_extent<_Tp[_Size]>
+    { typedef _Tp     type; };
+
+  template<typename _Tp>
+    struct remove_extent<_Tp[]>
+    { typedef _Tp     type; };
+
+  /// remove_all_extents
+  template<typename _Tp>
+    struct remove_all_extents
+    { typedef _Tp     type; };
+
+  template<typename _Tp, std::size_t _Size>
+    struct remove_all_extents<_Tp[_Size]>
+    { typedef typename remove_all_extents<_Tp>::type     type; };
+
+  template<typename _Tp>
+    struct remove_all_extents<_Tp[]>
+    { typedef typename remove_all_extents<_Tp>::type     type; };
+
+#if __cplusplus > 201103L
+  /// Alias template for remove_extent
+  template<typename _Tp>
+    using remove_extent_t = typename remove_extent<_Tp>::type;
+
+  /// Alias template for remove_all_extents
+  template<typename _Tp>
+    using remove_all_extents_t = typename remove_all_extents<_Tp>::type;
+#endif
+
+  // Pointer modifications.
+
+  template<typename _Tp, typename>
+    struct __remove_pointer_helper
+    { typedef _Tp     type; };
+
+  template<typename _Tp, typename _Up>
+    struct __remove_pointer_helper<_Tp, _Up*>
+    { typedef _Up     type; };
+
+  /// remove_pointer
+  template<typename _Tp>
+    struct remove_pointer
+    : public __remove_pointer_helper<_Tp, __remove_cv_t<_Tp>>
+    { };
+
+  template<typename _Tp, bool = __or_<__is_referenceable<_Tp>,
+				      is_void<_Tp>>::value>
+    struct __add_pointer_helper
+    { typedef _Tp     type; };
+
+  template<typename _Tp>
+    struct __add_pointer_helper<_Tp, true>
+    { typedef typename remove_reference<_Tp>::type*     type; };
+
+  /// add_pointer
+  template<typename _Tp>
+    struct add_pointer
+    : public __add_pointer_helper<_Tp>
+    { };
+
+#if __cplusplus > 201103L
+  /// Alias template for remove_pointer
+  template<typename _Tp>
+    using remove_pointer_t = typename remove_pointer<_Tp>::type;
+
+  /// Alias template for add_pointer
+  template<typename _Tp>
+    using add_pointer_t = typename add_pointer<_Tp>::type;
+#endif
+
+  template<std::size_t _Len>
+    struct __aligned_storage_msa
+    {
+      union __type
+      {
+	unsigned char __data[_Len];
+	struct __attribute__((__aligned__)) { } __align;
+      };
+    };
+
+  /**
+   *  @brief Alignment type.
+   *
+   *  The value of _Align is a default-alignment which shall be the
+   *  most stringent alignment requirement for any C++ object type
+   *  whose size is no greater than _Len (3.9). The member typedef
+   *  type shall be a POD type suitable for use as uninitialized
+   *  storage for any object whose size is at most _Len and whose
+   *  alignment is a divisor of _Align.
+  */
+  template<std::size_t _Len, std::size_t _Align =
+	   __alignof__(typename __aligned_storage_msa<_Len>::__type)>
+    struct aligned_storage
+    {
+      union type
+      {
+	unsigned char __data[_Len];
+	struct __attribute__((__aligned__((_Align)))) { } __align;
+      };
+    };
+
+  template <typename... _Types>
+    struct __strictest_alignment
+    {
+      static const size_t _S_alignment = 0;
+      static const size_t _S_size = 0;
+    };
+
+  template <typename _Tp, typename... _Types>
+    struct __strictest_alignment<_Tp, _Types...>
+    {
+      static const size_t _S_alignment =
+        alignof(_Tp) > __strictest_alignment<_Types...>::_S_alignment
+	? alignof(_Tp) : __strictest_alignment<_Types...>::_S_alignment;
+      static const size_t _S_size =
+        sizeof(_Tp) > __strictest_alignment<_Types...>::_S_size
+	? sizeof(_Tp) : __strictest_alignment<_Types...>::_S_size;
+    };
+
+  /**
+   *  @brief Provide aligned storage for types.
+   *
+   *  [meta.trans.other]
+   *
+   *  Provides aligned storage for any of the provided types of at
+   *  least size _Len.
+   *
+   *  @see aligned_storage
+   */
+  template <size_t _Len, typename... _Types>
+    struct aligned_union
+    {
+    private:
+      static_assert(sizeof...(_Types) != 0, "At least one type is required");
+
+      using __strictest = __strictest_alignment<_Types...>;
+      static const size_t _S_len = _Len > __strictest::_S_size
+	? _Len : __strictest::_S_size;
+    public:
+      /// The value of the strictest alignment of _Types.
+      static const size_t alignment_value = __strictest::_S_alignment;
+      /// The storage.
+      typedef typename aligned_storage<_S_len, alignment_value>::type type;
+    };
+
+  template <size_t _Len, typename... _Types>
+    const size_t aligned_union<_Len, _Types...>::alignment_value;
+
+  /// @cond undocumented
+
+  // Decay trait for arrays and functions, used for perfect forwarding
+  // in make_pair, make_tuple, etc.
+  template<typename _Up,
+	   bool _IsArray = is_array<_Up>::value,
+	   bool _IsFunction = is_function<_Up>::value>
+    struct __decay_selector;
+
+  // NB: DR 705.
+  template<typename _Up>
+    struct __decay_selector<_Up, false, false>
+    { typedef __remove_cv_t<_Up> __type; };
+
+  template<typename _Up>
+    struct __decay_selector<_Up, true, false>
+    { typedef typename remove_extent<_Up>::type* __type; };
+
+  template<typename _Up>
+    struct __decay_selector<_Up, false, true>
+    { typedef typename add_pointer<_Up>::type __type; };
+  /// @endcond
+
+  /// decay
+  template<typename _Tp>
+    class decay
+    {
+      typedef typename remove_reference<_Tp>::type __remove_type;
+
+    public:
+      typedef typename __decay_selector<__remove_type>::__type type;
+    };
+
+  /// @cond undocumented
+
+  // Helper which adds a reference to a type when given a reference_wrapper
+  template<typename _Tp>
+    struct __strip_reference_wrapper
+    {
+      typedef _Tp __type;
+    };
+
+  template<typename _Tp>
+    struct __strip_reference_wrapper<reference_wrapper<_Tp> >
+    {
+      typedef _Tp& __type;
+    };
+
+  // __decay_t (std::decay_t for C++11).
+  template<typename _Tp>
+    using __decay_t = typename decay<_Tp>::type;
+
+  template<typename _Tp>
+    using __decay_and_strip = __strip_reference_wrapper<__decay_t<_Tp>>;
+  /// @endcond
+
+  // Primary template.
+  /// Define a member typedef `type` only if a boolean constant is true.
+  template<bool, typename _Tp = void>
+    struct enable_if
+    { };
+
+  // Partial specialization for true.
+  template<typename _Tp>
+    struct enable_if<true, _Tp>
+    { typedef _Tp type; };
+
+  /// @cond undocumented
+
+  // __enable_if_t (std::enable_if_t for C++11)
+  template<bool _Cond, typename _Tp = void>
+    using __enable_if_t = typename enable_if<_Cond, _Tp>::type;
+
+  // Helper for SFINAE constraints
+  template<typename... _Cond>
+    using _Require = __enable_if_t<__and_<_Cond...>::value>;
+
+  // __remove_cvref_t (std::remove_cvref_t for C++11).
+  template<typename _Tp>
+    using __remove_cvref_t
+     = typename remove_cv<typename remove_reference<_Tp>::type>::type;
+  /// @endcond
+
+  // Primary template.
+  /// Define a member typedef @c type to one of two argument types.
+  template<bool _Cond, typename _Iftrue, typename _Iffalse>
+    struct conditional
+    { typedef _Iftrue type; };
+
+  // Partial specialization for false.
+  template<typename _Iftrue, typename _Iffalse>
+    struct conditional<false, _Iftrue, _Iffalse>
+    { typedef _Iffalse type; };
+
+  /// common_type
+  template<typename... _Tp>
+    struct common_type;
+
+  // Sfinae-friendly common_type implementation:
+
+  /// @cond undocumented
+  struct __do_common_type_impl
+  {
+    template<typename _Tp, typename _Up>
+      using __cond_t
+	= decltype(true ? std::declval<_Tp>() : std::declval<_Up>());
+
+    // if decay_t<decltype(false ? declval<D1>() : declval<D2>())>
+    // denotes a valid type, let C denote that type.
+    template<typename _Tp, typename _Up>
+      static __success_type<__decay_t<__cond_t<_Tp, _Up>>>
+      _S_test(int);
+
+#if __cplusplus > 201703L
+    // Otherwise, if COND-RES(CREF(D1), CREF(D2)) denotes a type,
+    // let C denote the type decay_t<COND-RES(CREF(D1), CREF(D2))>.
+    template<typename _Tp, typename _Up>
+      static __success_type<__remove_cvref_t<__cond_t<const _Tp&, const _Up&>>>
+      _S_test_2(int);
+#endif
+
+    template<typename, typename>
+      static __failure_type
+      _S_test_2(...);
+
+    template<typename _Tp, typename _Up>
+      static decltype(_S_test_2<_Tp, _Up>(0))
+      _S_test(...);
+  };
+
+  // If sizeof...(T) is zero, there shall be no member type.
+  template<>
+    struct common_type<>
+    { };
+
+  // If sizeof...(T) is one, the same type, if any, as common_type_t<T0, T0>.
+  template<typename _Tp0>
+    struct common_type<_Tp0>
+    : public common_type<_Tp0, _Tp0>
+    { };
+
+  // If sizeof...(T) is two, ...
+  template<typename _Tp1, typename _Tp2,
+	   typename _Dp1 = __decay_t<_Tp1>, typename _Dp2 = __decay_t<_Tp2>>
+    struct __common_type_impl
+    {
+      // If is_same_v<T1, D1> is false or is_same_v<T2, D2> is false,
+      // let C denote the same type, if any, as common_type_t<D1, D2>.
+      using type = common_type<_Dp1, _Dp2>;
+    };
+
+  template<typename _Tp1, typename _Tp2>
+    struct __common_type_impl<_Tp1, _Tp2, _Tp1, _Tp2>
+    : private __do_common_type_impl
+    {
+      // Otherwise, if decay_t<decltype(false ? declval<D1>() : declval<D2>())>
+      // denotes a valid type, let C denote that type.
+      using type = decltype(_S_test<_Tp1, _Tp2>(0));
+    };
+
+  // If sizeof...(T) is two, ...
+  template<typename _Tp1, typename _Tp2>
+    struct common_type<_Tp1, _Tp2>
+    : public __common_type_impl<_Tp1, _Tp2>::type
+    { };
+
+  template<typename...>
+    struct __common_type_pack
+    { };
+
+  template<typename, typename, typename = void>
+    struct __common_type_fold;
+
+  // If sizeof...(T) is greater than two, ...
+  template<typename _Tp1, typename _Tp2, typename... _Rp>
+    struct common_type<_Tp1, _Tp2, _Rp...>
+    : public __common_type_fold<common_type<_Tp1, _Tp2>,
+				__common_type_pack<_Rp...>>
+    { };
+
+  // Let C denote the same type, if any, as common_type_t<T1, T2>.
+  // If there is such a type C, type shall denote the same type, if any,
+  // as common_type_t<C, R...>.
+  template<typename _CTp, typename... _Rp>
+    struct __common_type_fold<_CTp, __common_type_pack<_Rp...>,
+			      __void_t<typename _CTp::type>>
+    : public common_type<typename _CTp::type, _Rp...>
+    { };
+
+  // Otherwise, there shall be no member type.
+  template<typename _CTp, typename _Rp>
+    struct __common_type_fold<_CTp, _Rp, void>
+    { };
+
+  template<typename _Tp, bool = is_enum<_Tp>::value>
+    struct __underlying_type_impl
+    {
+      using type = __underlying_type(_Tp);
+    };
+
+  template<typename _Tp>
+    struct __underlying_type_impl<_Tp, false>
+    { };
+  /// @endcond
+
+  /// The underlying type of an enum.
+  template<typename _Tp>
+    struct underlying_type
+    : public __underlying_type_impl<_Tp>
+    { };
+
+  /// @cond undocumented
+  template<typename _Tp>
+    struct __declval_protector
+    {
+      static const bool __stop = false;
+    };
+  /// @endcond
+
+  /** Utility to simplify expressions used in unevaluated operands
+   *  @since C++11
+   *  @ingroup utilities
+   */
+  template<typename _Tp>
+    auto declval() noexcept -> decltype(__declval<_Tp>(0))
+    {
+      static_assert(__declval_protector<_Tp>::__stop,
+		    "declval() must not be used!");
+      return __declval<_Tp>(0);
+    }
+
+  /// result_of
+  template<typename _Signature>
+    struct result_of;
+
+  // Sfinae-friendly result_of implementation:
+
+#define __cpp_lib_result_of_sfinae 201210L
+
+  /// @cond undocumented
+  struct __invoke_memfun_ref { };
+  struct __invoke_memfun_deref { };
+  struct __invoke_memobj_ref { };
+  struct __invoke_memobj_deref { };
+  struct __invoke_other { };
+
+  // Associate a tag type with a specialization of __success_type.
+  template<typename _Tp, typename _Tag>
+    struct __result_of_success : __success_type<_Tp>
+    { using __invoke_type = _Tag; };
+
+  // [func.require] paragraph 1 bullet 1:
+  struct __result_of_memfun_ref_impl
+  {
+    template<typename _Fp, typename _Tp1, typename... _Args>
+      static __result_of_success<decltype(
+      (std::declval<_Tp1>().*std::declval<_Fp>())(std::declval<_Args>()...)
+      ), __invoke_memfun_ref> _S_test(int);
+
+    template<typename...>
+      static __failure_type _S_test(...);
+  };
+
+  template<typename _MemPtr, typename _Arg, typename... _Args>
+    struct __result_of_memfun_ref
+    : private __result_of_memfun_ref_impl
+    {
+      typedef decltype(_S_test<_MemPtr, _Arg, _Args...>(0)) type;
+    };
+
+  // [func.require] paragraph 1 bullet 2:
+  struct __result_of_memfun_deref_impl
+  {
+    template<typename _Fp, typename _Tp1, typename... _Args>
+      static __result_of_success<decltype(
+      ((*std::declval<_Tp1>()).*std::declval<_Fp>())(std::declval<_Args>()...)
+      ), __invoke_memfun_deref> _S_test(int);
+
+    template<typename...>
+      static __failure_type _S_test(...);
+  };
+
+  template<typename _MemPtr, typename _Arg, typename... _Args>
+    struct __result_of_memfun_deref
+    : private __result_of_memfun_deref_impl
+    {
+      typedef decltype(_S_test<_MemPtr, _Arg, _Args...>(0)) type;
+    };
+
+  // [func.require] paragraph 1 bullet 3:
+  struct __result_of_memobj_ref_impl
+  {
+    template<typename _Fp, typename _Tp1>
+      static __result_of_success<decltype(
+      std::declval<_Tp1>().*std::declval<_Fp>()
+      ), __invoke_memobj_ref> _S_test(int);
+
+    template<typename, typename>
+      static __failure_type _S_test(...);
+  };
+
+  template<typename _MemPtr, typename _Arg>
+    struct __result_of_memobj_ref
+    : private __result_of_memobj_ref_impl
+    {
+      typedef decltype(_S_test<_MemPtr, _Arg>(0)) type;
+    };
+
+  // [func.require] paragraph 1 bullet 4:
+  struct __result_of_memobj_deref_impl
+  {
+    template<typename _Fp, typename _Tp1>
+      static __result_of_success<decltype(
+      (*std::declval<_Tp1>()).*std::declval<_Fp>()
+      ), __invoke_memobj_deref> _S_test(int);
+
+    template<typename, typename>
+      static __failure_type _S_test(...);
+  };
+
+  template<typename _MemPtr, typename _Arg>
+    struct __result_of_memobj_deref
+    : private __result_of_memobj_deref_impl
+    {
+      typedef decltype(_S_test<_MemPtr, _Arg>(0)) type;
+    };
+
+  template<typename _MemPtr, typename _Arg>
+    struct __result_of_memobj;
+
+  template<typename _Res, typename _Class, typename _Arg>
+    struct __result_of_memobj<_Res _Class::*, _Arg>
+    {
+      typedef __remove_cvref_t<_Arg> _Argval;
+      typedef _Res _Class::* _MemPtr;
+      typedef typename __conditional_t<__or_<is_same<_Argval, _Class>,
+        is_base_of<_Class, _Argval>>::value,
+        __result_of_memobj_ref<_MemPtr, _Arg>,
+        __result_of_memobj_deref<_MemPtr, _Arg>
+      >::type type;
+    };
+
+  template<typename _MemPtr, typename _Arg, typename... _Args>
+    struct __result_of_memfun;
+
+  template<typename _Res, typename _Class, typename _Arg, typename... _Args>
+    struct __result_of_memfun<_Res _Class::*, _Arg, _Args...>
+    {
+      typedef typename remove_reference<_Arg>::type _Argval;
+      typedef _Res _Class::* _MemPtr;
+      typedef typename __conditional_t<is_base_of<_Class, _Argval>::value,
+        __result_of_memfun_ref<_MemPtr, _Arg, _Args...>,
+        __result_of_memfun_deref<_MemPtr, _Arg, _Args...>
+      >::type type;
+    };
+
+  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+  // 2219.  INVOKE-ing a pointer to member with a reference_wrapper
+  //        as the object expression
+
+  // Used by result_of, invoke etc. to unwrap a reference_wrapper.
+  template<typename _Tp, typename _Up = __remove_cvref_t<_Tp>>
+    struct __inv_unwrap
+    {
+      using type = _Tp;
+    };
+
+  template<typename _Tp, typename _Up>
+    struct __inv_unwrap<_Tp, reference_wrapper<_Up>>
+    {
+      using type = _Up&;
+    };
+
+  template<bool, bool, typename _Functor, typename... _ArgTypes>
+    struct __result_of_impl
+    {
+      typedef __failure_type type;
+    };
+
+  template<typename _MemPtr, typename _Arg>
+    struct __result_of_impl<true, false, _MemPtr, _Arg>
+    : public __result_of_memobj<__decay_t<_MemPtr>,
+				typename __inv_unwrap<_Arg>::type>
+    { };
+
+  template<typename _MemPtr, typename _Arg, typename... _Args>
+    struct __result_of_impl<false, true, _MemPtr, _Arg, _Args...>
+    : public __result_of_memfun<__decay_t<_MemPtr>,
+				typename __inv_unwrap<_Arg>::type, _Args...>
+    { };
+
+  // [func.require] paragraph 1 bullet 5:
+  struct __result_of_other_impl
+  {
+    template<typename _Fn, typename... _Args>
+      static __result_of_success<decltype(
+      std::declval<_Fn>()(std::declval<_Args>()...)
+      ), __invoke_other> _S_test(int);
+
+    template<typename...>
+      static __failure_type _S_test(...);
+  };
+
+  template<typename _Functor, typename... _ArgTypes>
+    struct __result_of_impl<false, false, _Functor, _ArgTypes...>
+    : private __result_of_other_impl
+    {
+      typedef decltype(_S_test<_Functor, _ArgTypes...>(0)) type;
+    };
+
+  // __invoke_result (std::invoke_result for C++11)
+  template<typename _Functor, typename... _ArgTypes>
+    struct __invoke_result
+    : public __result_of_impl<
+        is_member_object_pointer<
+          typename remove_reference<_Functor>::type
+        >::value,
+        is_member_function_pointer<
+          typename remove_reference<_Functor>::type
+        >::value,
+	_Functor, _ArgTypes...
+      >::type
+    { };
+  /// @endcond
+
+  template<typename _Functor, typename... _ArgTypes>
+    struct result_of<_Functor(_ArgTypes...)>
+    : public __invoke_result<_Functor, _ArgTypes...>
+    { } _GLIBCXX17_DEPRECATED_SUGGEST("std::invoke_result");
+
+#if __cplusplus >= 201402L
+  /// Alias template for aligned_storage
+  template<size_t _Len, size_t _Align =
+	    __alignof__(typename __aligned_storage_msa<_Len>::__type)>
+    using aligned_storage_t = typename aligned_storage<_Len, _Align>::type;
+
+  template <size_t _Len, typename... _Types>
+    using aligned_union_t = typename aligned_union<_Len, _Types...>::type;
+
+  /// Alias template for decay
+  template<typename _Tp>
+    using decay_t = typename decay<_Tp>::type;
+
+  /// Alias template for enable_if
+  template<bool _Cond, typename _Tp = void>
+    using enable_if_t = typename enable_if<_Cond, _Tp>::type;
+
+  /// Alias template for conditional
+  template<bool _Cond, typename _Iftrue, typename _Iffalse>
+    using conditional_t = typename conditional<_Cond, _Iftrue, _Iffalse>::type;
+
+  /// Alias template for common_type
+  template<typename... _Tp>
+    using common_type_t = typename common_type<_Tp...>::type;
+
+  /// Alias template for underlying_type
+  template<typename _Tp>
+    using underlying_type_t = typename underlying_type<_Tp>::type;
+
+  /// Alias template for result_of
+  template<typename _Tp>
+    using result_of_t = typename result_of<_Tp>::type;
+#endif // C++14
+
+#if __cplusplus >= 201703L || !defined(__STRICT_ANSI__) // c++17 or gnu++11
+#define __cpp_lib_void_t 201411L
+  /// A metafunction that always yields void, used for detecting valid types.
+  template<typename...> using void_t = void;
+#endif
+
+  /// @cond undocumented
+
+  /// Implementation of the detection idiom (negative case).
+  template<typename _Default, typename _AlwaysVoid,
+	   template<typename...> class _Op, typename... _Args>
+    struct __detector
+    {
+      using value_t = false_type;
+      using type = _Default;
+    };
+
+  /// Implementation of the detection idiom (positive case).
+  template<typename _Default, template<typename...> class _Op,
+	    typename... _Args>
+    struct __detector<_Default, __void_t<_Op<_Args...>>, _Op, _Args...>
+    {
+      using value_t = true_type;
+      using type = _Op<_Args...>;
+    };
+
+  // Detect whether _Op<_Args...> is a valid type, use _Default if not.
+  template<typename _Default, template<typename...> class _Op,
+	   typename... _Args>
+    using __detected_or = __detector<_Default, void, _Op, _Args...>;
+
+  // _Op<_Args...> if that is a valid type, otherwise _Default.
+  template<typename _Default, template<typename...> class _Op,
+	   typename... _Args>
+    using __detected_or_t
+      = typename __detected_or<_Default, _Op, _Args...>::type;
+
+  /**
+   *  Use SFINAE to determine if the type _Tp has a publicly-accessible
+   *  member type _NTYPE.
+   */
+#define _GLIBCXX_HAS_NESTED_TYPE(_NTYPE)				\
+  template<typename _Tp, typename = __void_t<>>				\
+    struct __has_##_NTYPE						\
+    : false_type							\
+    { };								\
+  template<typename _Tp>						\
+    struct __has_##_NTYPE<_Tp, __void_t<typename _Tp::_NTYPE>>		\
+    : true_type								\
+    { };
+
+  template <typename _Tp>
+    struct __is_swappable;
+
+  template <typename _Tp>
+    struct __is_nothrow_swappable;
+
+  template<typename>
+    struct __is_tuple_like_impl : false_type
+    { };
+
+  // Internal type trait that allows us to sfinae-protect tuple_cat.
+  template<typename _Tp>
+    struct __is_tuple_like
+    : public __is_tuple_like_impl<__remove_cvref_t<_Tp>>::type
+    { };
+  /// @endcond
+
+  template<typename _Tp>
+    _GLIBCXX20_CONSTEXPR
+    inline
+    _Require<__not_<__is_tuple_like<_Tp>>,
+	     is_move_constructible<_Tp>,
+	     is_move_assignable<_Tp>>
+    swap(_Tp&, _Tp&)
+    noexcept(__and_<is_nothrow_move_constructible<_Tp>,
+	            is_nothrow_move_assignable<_Tp>>::value);
+
+  template<typename _Tp, size_t _Nm>
+    _GLIBCXX20_CONSTEXPR
+    inline
+    __enable_if_t<__is_swappable<_Tp>::value>
+    swap(_Tp (&__a)[_Nm], _Tp (&__b)[_Nm])
+    noexcept(__is_nothrow_swappable<_Tp>::value);
+
+  /// @cond undocumented
+  namespace __swappable_details {
+    using std::swap;
+
+    struct __do_is_swappable_impl
+    {
+      template<typename _Tp, typename
+               = decltype(swap(std::declval<_Tp&>(), std::declval<_Tp&>()))>
+        static true_type __test(int);
+
+      template<typename>
+        static false_type __test(...);
+    };
+
+    struct __do_is_nothrow_swappable_impl
+    {
+      template<typename _Tp>
+        static __bool_constant<
+          noexcept(swap(std::declval<_Tp&>(), std::declval<_Tp&>()))
+        > __test(int);
+
+      template<typename>
+        static false_type __test(...);
+    };
+
+  } // namespace __swappable_details
+
+  template<typename _Tp>
+    struct __is_swappable_impl
+    : public __swappable_details::__do_is_swappable_impl
+    {
+      typedef decltype(__test<_Tp>(0)) type;
+    };
+
+  template<typename _Tp>
+    struct __is_nothrow_swappable_impl
+    : public __swappable_details::__do_is_nothrow_swappable_impl
+    {
+      typedef decltype(__test<_Tp>(0)) type;
+    };
+
+  template<typename _Tp>
+    struct __is_swappable
+    : public __is_swappable_impl<_Tp>::type
+    { };
+
+  template<typename _Tp>
+    struct __is_nothrow_swappable
+    : public __is_nothrow_swappable_impl<_Tp>::type
+    { };
+  /// @endcond
+
+#if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11
+#define __cpp_lib_is_swappable 201603L
+  /// Metafunctions used for detecting swappable types: p0185r1
+
+  /// is_swappable
+  template<typename _Tp>
+    struct is_swappable
+    : public __is_swappable_impl<_Tp>::type
+    {
+      static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
+	"template argument must be a complete class or an unbounded array");
+    };
+
+  /// is_nothrow_swappable
+  template<typename _Tp>
+    struct is_nothrow_swappable
+    : public __is_nothrow_swappable_impl<_Tp>::type
+    {
+      static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
+	"template argument must be a complete class or an unbounded array");
+    };
+
+#if __cplusplus >= 201402L
+  /// is_swappable_v
+  template<typename _Tp>
+    _GLIBCXX17_INLINE constexpr bool is_swappable_v =
+      is_swappable<_Tp>::value;
+
+  /// is_nothrow_swappable_v
+  template<typename _Tp>
+    _GLIBCXX17_INLINE constexpr bool is_nothrow_swappable_v =
+      is_nothrow_swappable<_Tp>::value;
+#endif // __cplusplus >= 201402L
+
+  /// @cond undocumented
+  namespace __swappable_with_details {
+    using std::swap;
+
+    struct __do_is_swappable_with_impl
+    {
+      template<typename _Tp, typename _Up, typename
+               = decltype(swap(std::declval<_Tp>(), std::declval<_Up>())),
+               typename
+               = decltype(swap(std::declval<_Up>(), std::declval<_Tp>()))>
+        static true_type __test(int);
+
+      template<typename, typename>
+        static false_type __test(...);
+    };
+
+    struct __do_is_nothrow_swappable_with_impl
+    {
+      template<typename _Tp, typename _Up>
+        static __bool_constant<
+          noexcept(swap(std::declval<_Tp>(), std::declval<_Up>()))
+          &&
+          noexcept(swap(std::declval<_Up>(), std::declval<_Tp>()))
+        > __test(int);
+
+      template<typename, typename>
+        static false_type __test(...);
+    };
+
+  } // namespace __swappable_with_details
+
+  template<typename _Tp, typename _Up>
+    struct __is_swappable_with_impl
+    : public __swappable_with_details::__do_is_swappable_with_impl
+    {
+      typedef decltype(__test<_Tp, _Up>(0)) type;
+    };
+
+  // Optimization for the homogenous lvalue case, not required:
+  template<typename _Tp>
+    struct __is_swappable_with_impl<_Tp&, _Tp&>
+    : public __swappable_details::__do_is_swappable_impl
+    {
+      typedef decltype(__test<_Tp&>(0)) type;
+    };
+
+  template<typename _Tp, typename _Up>
+    struct __is_nothrow_swappable_with_impl
+    : public __swappable_with_details::__do_is_nothrow_swappable_with_impl
+    {
+      typedef decltype(__test<_Tp, _Up>(0)) type;
+    };
+
+  // Optimization for the homogenous lvalue case, not required:
+  template<typename _Tp>
+    struct __is_nothrow_swappable_with_impl<_Tp&, _Tp&>
+    : public __swappable_details::__do_is_nothrow_swappable_impl
+    {
+      typedef decltype(__test<_Tp&>(0)) type;
+    };
+  /// @endcond
+
+  /// is_swappable_with
+  template<typename _Tp, typename _Up>
+    struct is_swappable_with
+    : public __is_swappable_with_impl<_Tp, _Up>::type
+    {
+      static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
+	"first template argument must be a complete class or an unbounded array");
+      static_assert(std::__is_complete_or_unbounded(__type_identity<_Up>{}),
+	"second template argument must be a complete class or an unbounded array");
+    };
+
+  /// is_nothrow_swappable_with
+  template<typename _Tp, typename _Up>
+    struct is_nothrow_swappable_with
+    : public __is_nothrow_swappable_with_impl<_Tp, _Up>::type
+    {
+      static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
+	"first template argument must be a complete class or an unbounded array");
+      static_assert(std::__is_complete_or_unbounded(__type_identity<_Up>{}),
+	"second template argument must be a complete class or an unbounded array");
+    };
+
+#if __cplusplus >= 201402L
+  /// is_swappable_with_v
+  template<typename _Tp, typename _Up>
+    _GLIBCXX17_INLINE constexpr bool is_swappable_with_v =
+      is_swappable_with<_Tp, _Up>::value;
+
+  /// is_nothrow_swappable_with_v
+  template<typename _Tp, typename _Up>
+    _GLIBCXX17_INLINE constexpr bool is_nothrow_swappable_with_v =
+      is_nothrow_swappable_with<_Tp, _Up>::value;
+#endif // __cplusplus >= 201402L
+
+#endif// c++1z or gnu++11
+
+  /// @cond undocumented
+
+  // __is_invocable (std::is_invocable for C++11)
+
+  // The primary template is used for invalid INVOKE expressions.
+  template<typename _Result, typename _Ret,
+	   bool = is_void<_Ret>::value, typename = void>
+    struct __is_invocable_impl : false_type { };
+
+  // Used for valid INVOKE and INVOKE<void> expressions.
+  template<typename _Result, typename _Ret>
+    struct __is_invocable_impl<_Result, _Ret,
+			       /* is_void<_Ret> = */ true,
+			       __void_t<typename _Result::type>>
+    : true_type
+    { };
+
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wctor-dtor-privacy"
+  // Used for INVOKE<R> expressions to check the implicit conversion to R.
+  template<typename _Result, typename _Ret>
+    struct __is_invocable_impl<_Result, _Ret,
+			       /* is_void<_Ret> = */ false,
+			       __void_t<typename _Result::type>>
+    {
+    private:
+      // The type of the INVOKE expression.
+      // Unlike declval, this doesn't add_rvalue_reference.
+      static typename _Result::type _S_get();
+
+      template<typename _Tp>
+	static void _S_conv(_Tp);
+
+      // This overload is viable if INVOKE(f, args...) can convert to _Tp.
+      template<typename _Tp, typename = decltype(_S_conv<_Tp>(_S_get()))>
+	static true_type
+	_S_test(int);
+
+      template<typename _Tp>
+	static false_type
+	_S_test(...);
+
+    public:
+      using type = decltype(_S_test<_Ret>(1));
+    };
+#pragma GCC diagnostic pop
+
+  template<typename _Fn, typename... _ArgTypes>
+    struct __is_invocable
+    : __is_invocable_impl<__invoke_result<_Fn, _ArgTypes...>, void>::type
+    { };
+
+  template<typename _Fn, typename _Tp, typename... _Args>
+    constexpr bool __call_is_nt(__invoke_memfun_ref)
+    {
+      using _Up = typename __inv_unwrap<_Tp>::type;
+      return noexcept((std::declval<_Up>().*std::declval<_Fn>())(
+	    std::declval<_Args>()...));
+    }
+
+  template<typename _Fn, typename _Tp, typename... _Args>
+    constexpr bool __call_is_nt(__invoke_memfun_deref)
+    {
+      return noexcept(((*std::declval<_Tp>()).*std::declval<_Fn>())(
+	    std::declval<_Args>()...));
+    }
+
+  template<typename _Fn, typename _Tp>
+    constexpr bool __call_is_nt(__invoke_memobj_ref)
+    {
+      using _Up = typename __inv_unwrap<_Tp>::type;
+      return noexcept(std::declval<_Up>().*std::declval<_Fn>());
+    }
+
+  template<typename _Fn, typename _Tp>
+    constexpr bool __call_is_nt(__invoke_memobj_deref)
+    {
+      return noexcept((*std::declval<_Tp>()).*std::declval<_Fn>());
+    }
+
+  template<typename _Fn, typename... _Args>
+    constexpr bool __call_is_nt(__invoke_other)
+    {
+      return noexcept(std::declval<_Fn>()(std::declval<_Args>()...));
+    }
+
+  template<typename _Result, typename _Fn, typename... _Args>
+    struct __call_is_nothrow
+    : __bool_constant<
+	std::__call_is_nt<_Fn, _Args...>(typename _Result::__invoke_type{})
+      >
+    { };
+
+  template<typename _Fn, typename... _Args>
+    using __call_is_nothrow_
+      = __call_is_nothrow<__invoke_result<_Fn, _Args...>, _Fn, _Args...>;
+
+  // __is_nothrow_invocable (std::is_nothrow_invocable for C++11)
+  template<typename _Fn, typename... _Args>
+    struct __is_nothrow_invocable
+    : __and_<__is_invocable<_Fn, _Args...>,
+             __call_is_nothrow_<_Fn, _Args...>>::type
+    { };
+
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wctor-dtor-privacy"
+  struct __nonesuchbase {};
+  struct __nonesuch : private __nonesuchbase {
+    ~__nonesuch() = delete;
+    __nonesuch(__nonesuch const&) = delete;
+    void operator=(__nonesuch const&) = delete;
+  };
+#pragma GCC diagnostic pop
+  /// @endcond
+
+#if __cplusplus >= 201703L
+# define __cpp_lib_is_invocable 201703L
+
+  /// std::invoke_result
+  template<typename _Functor, typename... _ArgTypes>
+    struct invoke_result
+    : public __invoke_result<_Functor, _ArgTypes...>
+    {
+      static_assert(std::__is_complete_or_unbounded(__type_identity<_Functor>{}),
+	"_Functor must be a complete class or an unbounded array");
+      static_assert((std::__is_complete_or_unbounded(
+	__type_identity<_ArgTypes>{}) && ...),
+	"each argument type must be a complete class or an unbounded array");
+    };
+
+  /// std::invoke_result_t
+  template<typename _Fn, typename... _Args>
+    using invoke_result_t = typename invoke_result<_Fn, _Args...>::type;
+
+  /// std::is_invocable
+  template<typename _Fn, typename... _ArgTypes>
+    struct is_invocable
+    : __is_invocable_impl<__invoke_result<_Fn, _ArgTypes...>, void>::type
+    {
+      static_assert(std::__is_complete_or_unbounded(__type_identity<_Fn>{}),
+	"_Fn must be a complete class or an unbounded array");
+      static_assert((std::__is_complete_or_unbounded(
+	__type_identity<_ArgTypes>{}) && ...),
+	"each argument type must be a complete class or an unbounded array");
+    };
+
+  /// std::is_invocable_r
+  template<typename _Ret, typename _Fn, typename... _ArgTypes>
+    struct is_invocable_r
+    : __is_invocable_impl<__invoke_result<_Fn, _ArgTypes...>, _Ret>::type
+    {
+      static_assert(std::__is_complete_or_unbounded(__type_identity<_Fn>{}),
+	"_Fn must be a complete class or an unbounded array");
+      static_assert((std::__is_complete_or_unbounded(
+	__type_identity<_ArgTypes>{}) && ...),
+	"each argument type must be a complete class or an unbounded array");
+      static_assert(std::__is_complete_or_unbounded(__type_identity<_Ret>{}),
+	"_Ret must be a complete class or an unbounded array");
+    };
+
+  /// std::is_nothrow_invocable
+  template<typename _Fn, typename... _ArgTypes>
+    struct is_nothrow_invocable
+    : __and_<__is_invocable_impl<__invoke_result<_Fn, _ArgTypes...>, void>,
+	     __call_is_nothrow_<_Fn, _ArgTypes...>>::type
+    {
+      static_assert(std::__is_complete_or_unbounded(__type_identity<_Fn>{}),
+	"_Fn must be a complete class or an unbounded array");
+      static_assert((std::__is_complete_or_unbounded(
+	__type_identity<_ArgTypes>{}) && ...),
+	"each argument type must be a complete class or an unbounded array");
+    };
+
+  /// @cond undocumented
+  template<typename _Result, typename _Ret, typename = void>
+    struct __is_nt_invocable_impl : false_type { };
+
+  template<typename _Result, typename _Ret>
+    struct __is_nt_invocable_impl<_Result, _Ret,
+				  __void_t<typename _Result::type>>
+    : __or_<is_void<_Ret>,
+	    __is_nothrow_convertible<typename _Result::type, _Ret>>
+    { };
+  /// @endcond
+
+  /// std::is_nothrow_invocable_r
+  template<typename _Ret, typename _Fn, typename... _ArgTypes>
+    struct is_nothrow_invocable_r
+    : __and_<__is_nt_invocable_impl<__invoke_result<_Fn, _ArgTypes...>, _Ret>,
+             __call_is_nothrow_<_Fn, _ArgTypes...>>::type
+    {
+      static_assert(std::__is_complete_or_unbounded(__type_identity<_Fn>{}),
+	"_Fn must be a complete class or an unbounded array");
+      static_assert((std::__is_complete_or_unbounded(
+	__type_identity<_ArgTypes>{}) && ...),
+	"each argument type must be a complete class or an unbounded array");
+      static_assert(std::__is_complete_or_unbounded(__type_identity<_Ret>{}),
+	"_Ret must be a complete class or an unbounded array");
+    };
+#endif // C++17
+
+#if __cplusplus >= 201703L
+# define __cpp_lib_type_trait_variable_templates 201510L
+  /**
+   * @defgroup variable_templates Variable templates for type traits
+   * @ingroup metaprogramming
+   *
+   * Each variable `is_xxx_v<T>` is a boolean constant with the same value
+   * as the `value` member of the corresponding type trait `is_xxx<T>`.
+   *
+   * @since C++17 unless noted otherwise.
+   */
+
+  /**
+   * @{
+   * @ingroup variable_templates
+   */
+template <typename _Tp>
+  inline constexpr bool is_void_v = is_void<_Tp>::value;
+template <typename _Tp>
+  inline constexpr bool is_null_pointer_v = is_null_pointer<_Tp>::value;
+template <typename _Tp>
+  inline constexpr bool is_integral_v = is_integral<_Tp>::value;
+template <typename _Tp>
+  inline constexpr bool is_floating_point_v = is_floating_point<_Tp>::value;
+template <typename _Tp>
+  inline constexpr bool is_array_v = is_array<_Tp>::value;
+template <typename _Tp>
+  inline constexpr bool is_pointer_v = is_pointer<_Tp>::value;
+template <typename _Tp>
+  inline constexpr bool is_lvalue_reference_v =
+    is_lvalue_reference<_Tp>::value;
+template <typename _Tp>
+  inline constexpr bool is_rvalue_reference_v =
+    is_rvalue_reference<_Tp>::value;
+template <typename _Tp>
+  inline constexpr bool is_member_object_pointer_v =
+    is_member_object_pointer<_Tp>::value;
+template <typename _Tp>
+  inline constexpr bool is_member_function_pointer_v =
+    is_member_function_pointer<_Tp>::value;
+template <typename _Tp>
+  inline constexpr bool is_enum_v = is_enum<_Tp>::value;
+template <typename _Tp>
+  inline constexpr bool is_union_v = is_union<_Tp>::value;
+template <typename _Tp>
+  inline constexpr bool is_class_v = is_class<_Tp>::value;
+template <typename _Tp>
+  inline constexpr bool is_function_v = is_function<_Tp>::value;
+template <typename _Tp>
+  inline constexpr bool is_reference_v = is_reference<_Tp>::value;
+template <typename _Tp>
+  inline constexpr bool is_arithmetic_v = is_arithmetic<_Tp>::value;
+template <typename _Tp>
+  inline constexpr bool is_fundamental_v = is_fundamental<_Tp>::value;
+template <typename _Tp>
+  inline constexpr bool is_object_v = is_object<_Tp>::value;
+template <typename _Tp>
+  inline constexpr bool is_scalar_v = is_scalar<_Tp>::value;
+template <typename _Tp>
+  inline constexpr bool is_compound_v = is_compound<_Tp>::value;
+template <typename _Tp>
+  inline constexpr bool is_member_pointer_v = is_member_pointer<_Tp>::value;
+template <typename _Tp>
+  inline constexpr bool is_const_v = is_const<_Tp>::value;
+template <typename _Tp>
+  inline constexpr bool is_volatile_v = is_volatile<_Tp>::value;
+template <typename _Tp>
+  inline constexpr bool is_trivial_v = is_trivial<_Tp>::value;
+template <typename _Tp>
+  inline constexpr bool is_trivially_copyable_v =
+    is_trivially_copyable<_Tp>::value;
+template <typename _Tp>
+  inline constexpr bool is_standard_layout_v = is_standard_layout<_Tp>::value;
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+template <typename _Tp>
+  _GLIBCXX20_DEPRECATED("use is_standard_layout_v && is_trivial_v instead")
+  inline constexpr bool is_pod_v = is_pod<_Tp>::value;
+template <typename _Tp>
+  _GLIBCXX17_DEPRECATED
+  inline constexpr bool is_literal_type_v = is_literal_type<_Tp>::value;
+#pragma GCC diagnostic pop
+ template <typename _Tp>
+  inline constexpr bool is_empty_v = is_empty<_Tp>::value;
+template <typename _Tp>
+  inline constexpr bool is_polymorphic_v = is_polymorphic<_Tp>::value;
+template <typename _Tp>
+  inline constexpr bool is_abstract_v = is_abstract<_Tp>::value;
+template <typename _Tp>
+  inline constexpr bool is_final_v = is_final<_Tp>::value;
+template <typename _Tp>
+  inline constexpr bool is_signed_v = is_signed<_Tp>::value;
+template <typename _Tp>
+  inline constexpr bool is_unsigned_v = is_unsigned<_Tp>::value;
+template <typename _Tp, typename... _Args>
+  inline constexpr bool is_constructible_v =
+    is_constructible<_Tp, _Args...>::value;
+template <typename _Tp>
+  inline constexpr bool is_default_constructible_v =
+    is_default_constructible<_Tp>::value;
+template <typename _Tp>
+  inline constexpr bool is_copy_constructible_v =
+    is_copy_constructible<_Tp>::value;
+template <typename _Tp>
+  inline constexpr bool is_move_constructible_v =
+    is_move_constructible<_Tp>::value;
+template <typename _Tp, typename _Up>
+  inline constexpr bool is_assignable_v = is_assignable<_Tp, _Up>::value;
+template <typename _Tp>
+  inline constexpr bool is_copy_assignable_v = is_copy_assignable<_Tp>::value;
+template <typename _Tp>
+  inline constexpr bool is_move_assignable_v = is_move_assignable<_Tp>::value;
+template <typename _Tp>
+  inline constexpr bool is_destructible_v = is_destructible<_Tp>::value;
+template <typename _Tp, typename... _Args>
+  inline constexpr bool is_trivially_constructible_v =
+    is_trivially_constructible<_Tp, _Args...>::value;
+template <typename _Tp>
+  inline constexpr bool is_trivially_default_constructible_v =
+    is_trivially_default_constructible<_Tp>::value;
+template <typename _Tp>
+  inline constexpr bool is_trivially_copy_constructible_v =
+    is_trivially_copy_constructible<_Tp>::value;
+template <typename _Tp>
+  inline constexpr bool is_trivially_move_constructible_v =
+    is_trivially_move_constructible<_Tp>::value;
+template <typename _Tp, typename _Up>
+  inline constexpr bool is_trivially_assignable_v =
+    is_trivially_assignable<_Tp, _Up>::value;
+template <typename _Tp>
+  inline constexpr bool is_trivially_copy_assignable_v =
+    is_trivially_copy_assignable<_Tp>::value;
+template <typename _Tp>
+  inline constexpr bool is_trivially_move_assignable_v =
+    is_trivially_move_assignable<_Tp>::value;
+template <typename _Tp>
+  inline constexpr bool is_trivially_destructible_v =
+    is_trivially_destructible<_Tp>::value;
+template <typename _Tp, typename... _Args>
+  inline constexpr bool is_nothrow_constructible_v =
+    is_nothrow_constructible<_Tp, _Args...>::value;
+template <typename _Tp>
+  inline constexpr bool is_nothrow_default_constructible_v =
+    is_nothrow_default_constructible<_Tp>::value;
+template <typename _Tp>
+  inline constexpr bool is_nothrow_copy_constructible_v =
+    is_nothrow_copy_constructible<_Tp>::value;
+template <typename _Tp>
+  inline constexpr bool is_nothrow_move_constructible_v =
+    is_nothrow_move_constructible<_Tp>::value;
+template <typename _Tp, typename _Up>
+  inline constexpr bool is_nothrow_assignable_v =
+    is_nothrow_assignable<_Tp, _Up>::value;
+template <typename _Tp>
+  inline constexpr bool is_nothrow_copy_assignable_v =
+    is_nothrow_copy_assignable<_Tp>::value;
+template <typename _Tp>
+  inline constexpr bool is_nothrow_move_assignable_v =
+    is_nothrow_move_assignable<_Tp>::value;
+template <typename _Tp>
+  inline constexpr bool is_nothrow_destructible_v =
+    is_nothrow_destructible<_Tp>::value;
+template <typename _Tp>
+  inline constexpr bool has_virtual_destructor_v =
+    has_virtual_destructor<_Tp>::value;
+template <typename _Tp>
+  inline constexpr size_t alignment_of_v = alignment_of<_Tp>::value;
+template <typename _Tp>
+  inline constexpr size_t rank_v = rank<_Tp>::value;
+template <typename _Tp, unsigned _Idx = 0>
+  inline constexpr size_t extent_v = extent<_Tp, _Idx>::value;
+#ifdef _GLIBCXX_HAVE_BUILTIN_IS_SAME
+template <typename _Tp, typename _Up>
+  inline constexpr bool is_same_v = __is_same(_Tp, _Up);
+#else
+template <typename _Tp, typename _Up>
+  inline constexpr bool is_same_v = std::is_same<_Tp, _Up>::value;
+#endif
+template <typename _Base, typename _Derived>
+  inline constexpr bool is_base_of_v = is_base_of<_Base, _Derived>::value;
+template <typename _From, typename _To>
+  inline constexpr bool is_convertible_v = is_convertible<_From, _To>::value;
+template<typename _Fn, typename... _Args>
+  inline constexpr bool is_invocable_v = is_invocable<_Fn, _Args...>::value;
+template<typename _Fn, typename... _Args>
+  inline constexpr bool is_nothrow_invocable_v
+    = is_nothrow_invocable<_Fn, _Args...>::value;
+template<typename _Ret, typename _Fn, typename... _Args>
+  inline constexpr bool is_invocable_r_v
+    = is_invocable_r<_Ret, _Fn, _Args...>::value;
+template<typename _Ret, typename _Fn, typename... _Args>
+  inline constexpr bool is_nothrow_invocable_r_v
+    = is_nothrow_invocable_r<_Ret, _Fn, _Args...>::value;
+/// @}
+
+#ifdef _GLIBCXX_HAVE_BUILTIN_HAS_UNIQ_OBJ_REP
+# define __cpp_lib_has_unique_object_representations 201606L
+  /// has_unique_object_representations
+  /// @since C++17
+  template<typename _Tp>
+    struct has_unique_object_representations
+    : bool_constant<__has_unique_object_representations(
+      remove_cv_t<remove_all_extents_t<_Tp>>
+      )>
+    {
+      static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
+	"template argument must be a complete class or an unbounded array");
+    };
+
+  /// @ingroup variable_templates
+  template<typename _Tp>
+    inline constexpr bool has_unique_object_representations_v
+      = has_unique_object_representations<_Tp>::value;
+#endif
+
+#ifdef _GLIBCXX_HAVE_BUILTIN_IS_AGGREGATE
+# define __cpp_lib_is_aggregate 201703L
+  /// is_aggregate
+  /// @since C++17
+  template<typename _Tp>
+    struct is_aggregate
+    : bool_constant<__is_aggregate(remove_cv_t<_Tp>)>
+    { };
+
+  /// @ingroup variable_templates
+  template<typename _Tp>
+    inline constexpr bool is_aggregate_v = is_aggregate<_Tp>::value;
+#endif
+#endif // C++17
+
+#if __cplusplus >= 202002L
+
+  /** * Remove references and cv-qualifiers.
+   * @since C++20
+   * @{
+   */
+#define __cpp_lib_remove_cvref 201711L
+
+  template<typename _Tp>
+    struct remove_cvref
+    : remove_cv<_Tp>
+    { };
+
+  template<typename _Tp>
+    struct remove_cvref<_Tp&>
+    : remove_cv<_Tp>
+    { };
+
+  template<typename _Tp>
+    struct remove_cvref<_Tp&&>
+    : remove_cv<_Tp>
+    { };
+
+  template<typename _Tp>
+    using remove_cvref_t = typename remove_cvref<_Tp>::type;
+  /// @}
+
+  /** * Identity metafunction.
+   * @since C++20
+   * @{
+   */
+#define __cpp_lib_type_identity 201806L
+  template<typename _Tp>
+    struct type_identity { using type = _Tp; };
+
+  template<typename _Tp>
+    using type_identity_t = typename type_identity<_Tp>::type;
+  /// @}
+
+#define __cpp_lib_unwrap_ref 201811L
+
+  /** Unwrap a reference_wrapper
+   * @since C++20
+   * @{
+   */
+  template<typename _Tp>
+    struct unwrap_reference { using type = _Tp; };
+
+  template<typename _Tp>
+    struct unwrap_reference<reference_wrapper<_Tp>> { using type = _Tp&; };
+
+  template<typename _Tp>
+    using unwrap_reference_t = typename unwrap_reference<_Tp>::type;
+  /// @}
+
+  /** Decay type and if it's a reference_wrapper, unwrap it
+   * @since C++20
+   * @{
+   */
+  template<typename _Tp>
+    struct unwrap_ref_decay { using type = unwrap_reference_t<decay_t<_Tp>>; };
+
+  template<typename _Tp>
+    using unwrap_ref_decay_t = typename unwrap_ref_decay<_Tp>::type;
+  /// @}
+
+#define __cpp_lib_bounded_array_traits 201902L
+
+  /// True for a type that is an array of known bound.
+  /// @since C++20
+  template<typename _Tp>
+    struct is_bounded_array
+    : public __is_array_known_bounds<_Tp>
+    { };
+
+  /// True for a type that is an array of unknown bound.
+  /// @since C++20
+  template<typename _Tp>
+    struct is_unbounded_array
+    : public __is_array_unknown_bounds<_Tp>
+    { };
+
+  /// @ingroup variable_templates
+  /// @since C++20
+  template<typename _Tp>
+    inline constexpr bool is_bounded_array_v
+      = is_bounded_array<_Tp>::value;
+
+  /// @ingroup variable_templates
+  /// @since C++20
+  template<typename _Tp>
+    inline constexpr bool is_unbounded_array_v
+      = is_unbounded_array<_Tp>::value;
+
+#if __has_builtin(__is_layout_compatible)
+
+  /// @since C++20
+  template<typename _Tp, typename _Up>
+    struct is_layout_compatible
+    : bool_constant<__is_layout_compatible(_Tp, _Up)>
+    { };
+
+  /// @ingroup variable_templates
+  /// @since C++20
+  template<typename _Tp, typename _Up>
+    constexpr bool is_layout_compatible_v
+      = __is_layout_compatible(_Tp, _Up);
+
+#if __has_builtin(__builtin_is_corresponding_member)
+#define __cpp_lib_is_layout_compatible 201907L
+
+  /// @since C++20
+  template<typename _S1, typename _S2, typename _M1, typename _M2>
+    constexpr bool
+    is_corresponding_member(_M1 _S1::*__m1, _M2 _S2::*__m2) noexcept
+    { return __builtin_is_corresponding_member(__m1, __m2); }
+#endif
+#endif
+
+#if __has_builtin(__is_pointer_interconvertible_base_of)
+  /// True if `_Derived` is standard-layout and has a base class of type `_Base`
+  /// @since C++20
+  template<typename _Base, typename _Derived>
+    struct is_pointer_interconvertible_base_of
+    : bool_constant<__is_pointer_interconvertible_base_of(_Base, _Derived)>
+    { };
+
+  /// @ingroup variable_templates
+  /// @since C++20
+  template<typename _Base, typename _Derived>
+    constexpr bool is_pointer_interconvertible_base_of_v
+      = __is_pointer_interconvertible_base_of(_Base, _Derived);
+
+#if __has_builtin(__builtin_is_pointer_interconvertible_with_class)
+#define __cpp_lib_is_pointer_interconvertible 201907L
+
+  /// True if `__mp` points to the first member of a standard-layout type
+  /// @returns true if `s.*__mp` is pointer-interconvertible with `s`
+  /// @since C++20
+  template<typename _Tp, typename _Mem>
+    constexpr bool
+    is_pointer_interconvertible_with_class(_Mem _Tp::*__mp) noexcept
+    { return __builtin_is_pointer_interconvertible_with_class(__mp); }
+#endif
+#endif
+
+#if __cplusplus > 202002L
+#define __cpp_lib_is_scoped_enum 202011L
+
+  /// True if the type is a scoped enumeration type.
+  /// @since C++23
+
+  template<typename _Tp>
+    struct is_scoped_enum
+    : false_type
+    { };
+
+  template<typename _Tp>
+    requires __is_enum(_Tp)
+    && requires(_Tp __t) { __t = __t; } // fails if incomplete
+    struct is_scoped_enum<_Tp>
+    : bool_constant<!requires(_Tp __t, void(*__f)(int)) { __f(__t); }>
+    { };
+
+  // FIXME remove this partial specialization and use remove_cv_t<_Tp> above
+  // when PR c++/99968 is fixed.
+  template<typename _Tp>
+    requires __is_enum(_Tp)
+    && requires(_Tp __t) { __t = __t; } // fails if incomplete
+    struct is_scoped_enum<const _Tp>
+    : bool_constant<!requires(_Tp __t, void(*__f)(int)) { __f(__t); }>
+    { };
+
+  /// @ingroup variable_templates
+  /// @since C++23
+  template<typename _Tp>
+    inline constexpr bool is_scoped_enum_v = is_scoped_enum<_Tp>::value;
+
+#endif // C++23
+
+#if _GLIBCXX_HAVE_IS_CONSTANT_EVALUATED
+#define __cpp_lib_is_constant_evaluated 201811L
+
+  /// Returns true only when called during constant evaluation.
+  /// @since C++20
+  constexpr inline bool
+  is_constant_evaluated() noexcept
+  {
+#if __cpp_if_consteval >= 202106L
+    if consteval { return true; } else { return false; }
+#else
+    return __builtin_is_constant_evaluated();
+#endif
+  }
+#endif
+
+  /// @cond undocumented
+  template<typename _From, typename _To>
+    using __copy_cv = typename __match_cv_qualifiers<_From, _To>::__type;
+
+  template<typename _Xp, typename _Yp>
+    using __cond_res
+      = decltype(false ? declval<_Xp(&)()>()() : declval<_Yp(&)()>()());
+
+  template<typename _Ap, typename _Bp, typename = void>
+    struct __common_ref_impl
+    { };
+
+  // [meta.trans.other], COMMON-REF(A, B)
+  template<typename _Ap, typename _Bp>
+    using __common_ref = typename __common_ref_impl<_Ap, _Bp>::type;
+
+  // COND-RES(COPYCV(X, Y) &, COPYCV(Y, X) &)
+  template<typename _Xp, typename _Yp>
+    using __condres_cvref
+      = __cond_res<__copy_cv<_Xp, _Yp>&, __copy_cv<_Yp, _Xp>&>;
+
+  // If A and B are both lvalue reference types, ...
+  template<typename _Xp, typename _Yp>
+    struct __common_ref_impl<_Xp&, _Yp&, __void_t<__condres_cvref<_Xp, _Yp>>>
+    : enable_if<is_reference_v<__condres_cvref<_Xp, _Yp>>,
+		__condres_cvref<_Xp, _Yp>>
+    { };
+
+  // let C be remove_reference_t<COMMON-REF(X&, Y&)>&&
+  template<typename _Xp, typename _Yp>
+    using __common_ref_C = remove_reference_t<__common_ref<_Xp&, _Yp&>>&&;
+
+  // If A and B are both rvalue reference types, ...
+  template<typename _Xp, typename _Yp>
+    struct __common_ref_impl<_Xp&&, _Yp&&,
+      _Require<is_convertible<_Xp&&, __common_ref_C<_Xp, _Yp>>,
+	       is_convertible<_Yp&&, __common_ref_C<_Xp, _Yp>>>>
+    { using type = __common_ref_C<_Xp, _Yp>; };
+
+  // let D be COMMON-REF(const X&, Y&)
+  template<typename _Xp, typename _Yp>
+    using __common_ref_D = __common_ref<const _Xp&, _Yp&>;
+
+  // If A is an rvalue reference and B is an lvalue reference, ...
+  template<typename _Xp, typename _Yp>
+    struct __common_ref_impl<_Xp&&, _Yp&,
+      _Require<is_convertible<_Xp&&, __common_ref_D<_Xp, _Yp>>>>
+    { using type = __common_ref_D<_Xp, _Yp>; };
+
+  // If A is an lvalue reference and B is an rvalue reference, ...
+  template<typename _Xp, typename _Yp>
+    struct __common_ref_impl<_Xp&, _Yp&&>
+    : __common_ref_impl<_Yp&&, _Xp&>
+    { };
+  /// @endcond
+
+  template<typename _Tp, typename _Up,
+	   template<typename> class _TQual, template<typename> class _UQual>
+    struct basic_common_reference
+    { };
+
+  /// @cond undocumented
+  template<typename _Tp>
+    struct __xref
+    { template<typename _Up> using __type = __copy_cv<_Tp, _Up>; };
+
+  template<typename _Tp>
+    struct __xref<_Tp&>
+    { template<typename _Up> using __type = __copy_cv<_Tp, _Up>&; };
+
+  template<typename _Tp>
+    struct __xref<_Tp&&>
+    { template<typename _Up> using __type = __copy_cv<_Tp, _Up>&&; };
+
+  template<typename _Tp1, typename _Tp2>
+    using __basic_common_ref
+      = typename basic_common_reference<remove_cvref_t<_Tp1>,
+					remove_cvref_t<_Tp2>,
+					__xref<_Tp1>::template __type,
+					__xref<_Tp2>::template __type>::type;
+  /// @endcond
+
+  template<typename... _Tp>
+    struct common_reference;
+
+  template<typename... _Tp>
+    using common_reference_t = typename common_reference<_Tp...>::type;
+
+  // If sizeof...(T) is zero, there shall be no member type.
+  template<>
+    struct common_reference<>
+    { };
+
+  // If sizeof...(T) is one ...
+  template<typename _Tp0>
+    struct common_reference<_Tp0>
+    { using type = _Tp0; };
+
+  /// @cond undocumented
+  template<typename _Tp1, typename _Tp2, int _Bullet = 1, typename = void>
+    struct __common_reference_impl
+    : __common_reference_impl<_Tp1, _Tp2, _Bullet + 1>
+    { };
+
+  // If sizeof...(T) is two ...
+  template<typename _Tp1, typename _Tp2>
+    struct common_reference<_Tp1, _Tp2>
+    : __common_reference_impl<_Tp1, _Tp2>
+    { };
+
+  // If T1 and T2 are reference types and COMMON-REF(T1, T2) is well-formed, ...
+  template<typename _Tp1, typename _Tp2>
+    struct __common_reference_impl<_Tp1&, _Tp2&, 1,
+				   void_t<__common_ref<_Tp1&, _Tp2&>>>
+    { using type = __common_ref<_Tp1&, _Tp2&>; };
+
+  template<typename _Tp1, typename _Tp2>
+    struct __common_reference_impl<_Tp1&&, _Tp2&&, 1,
+				   void_t<__common_ref<_Tp1&&, _Tp2&&>>>
+    { using type = __common_ref<_Tp1&&, _Tp2&&>; };
+
+  template<typename _Tp1, typename _Tp2>
+    struct __common_reference_impl<_Tp1&, _Tp2&&, 1,
+				   void_t<__common_ref<_Tp1&, _Tp2&&>>>
+    { using type = __common_ref<_Tp1&, _Tp2&&>; };
+
+  template<typename _Tp1, typename _Tp2>
+    struct __common_reference_impl<_Tp1&&, _Tp2&, 1,
+				   void_t<__common_ref<_Tp1&&, _Tp2&>>>
+    { using type = __common_ref<_Tp1&&, _Tp2&>; };
+
+  // Otherwise, if basic_common_reference<...>::type is well-formed, ...
+  template<typename _Tp1, typename _Tp2>
+    struct __common_reference_impl<_Tp1, _Tp2, 2,
+				   void_t<__basic_common_ref<_Tp1, _Tp2>>>
+    { using type = __basic_common_ref<_Tp1, _Tp2>; };
+
+  // Otherwise, if COND-RES(T1, T2) is well-formed, ...
+  template<typename _Tp1, typename _Tp2>
+    struct __common_reference_impl<_Tp1, _Tp2, 3,
+				   void_t<__cond_res<_Tp1, _Tp2>>>
+    { using type = __cond_res<_Tp1, _Tp2>; };
+
+  // Otherwise, if common_type_t<T1, T2> is well-formed, ...
+  template<typename _Tp1, typename _Tp2>
+    struct __common_reference_impl<_Tp1, _Tp2, 4,
+				   void_t<common_type_t<_Tp1, _Tp2>>>
+    { using type = common_type_t<_Tp1, _Tp2>; };
+
+  // Otherwise, there shall be no member type.
+  template<typename _Tp1, typename _Tp2>
+    struct __common_reference_impl<_Tp1, _Tp2, 5, void>
+    { };
+
+  // Otherwise, if sizeof...(T) is greater than two, ...
+  template<typename _Tp1, typename _Tp2, typename... _Rest>
+    struct common_reference<_Tp1, _Tp2, _Rest...>
+    : __common_type_fold<common_reference<_Tp1, _Tp2>,
+			 __common_type_pack<_Rest...>>
+    { };
+
+  // Reuse __common_type_fold for common_reference<T1, T2, Rest...>
+  template<typename _Tp1, typename _Tp2, typename... _Rest>
+    struct __common_type_fold<common_reference<_Tp1, _Tp2>,
+			      __common_type_pack<_Rest...>,
+			      void_t<common_reference_t<_Tp1, _Tp2>>>
+    : public common_reference<common_reference_t<_Tp1, _Tp2>, _Rest...>
+    { };
+  /// @endcond
+
+#endif // C++2a
+
+  /// @} group metaprogramming
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif  // C++11
+
+#endif  // _GLIBCXX_TYPE_TRAITS
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@typeindex b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@typeindex
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@@ -0,0 +1,129 @@
+// C++11 <typeindex> -*- C++ -*-
+
+// Copyright (C) 2010-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file include/typeindex
+ *  This is a Standard C++ Library header.
+ */
+
+#ifndef _GLIBCXX_TYPEINDEX
+#define _GLIBCXX_TYPEINDEX 1
+
+#pragma GCC system_header
+
+#if __cplusplus < 201103L
+# include <bits/c++0x_warning.h>
+#else
+
+#include <typeinfo>
+#if __cplusplus > 201703L
+# include <compare>
+#endif
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /**
+   * @brief Class type_index
+   * @ingroup utilities
+   *
+   *  The class type_index provides a simple wrapper for type_info
+   *  which can be used as an index type in associative containers
+   *  (23.6) and in unordered associative containers (23.7).
+   */
+  struct type_index
+  {
+    type_index(const type_info& __rhs) noexcept
+    : _M_target(&__rhs) { }
+
+    bool
+    operator==(const type_index& __rhs) const noexcept
+    { return *_M_target == *__rhs._M_target; }
+
+#if ! __cpp_lib_three_way_comparison
+    bool
+    operator!=(const type_index& __rhs) const noexcept
+    { return *_M_target != *__rhs._M_target; }
+#endif
+
+    bool
+    operator<(const type_index& __rhs) const noexcept
+    { return _M_target->before(*__rhs._M_target); }
+
+    bool
+    operator<=(const type_index& __rhs) const noexcept
+    { return !__rhs._M_target->before(*_M_target); }
+
+    bool
+    operator>(const type_index& __rhs) const noexcept
+    { return __rhs._M_target->before(*_M_target); }
+
+    bool
+    operator>=(const type_index& __rhs) const noexcept
+    { return !_M_target->before(*__rhs._M_target); }
+
+#if __cpp_lib_three_way_comparison
+    strong_ordering
+    operator<=>(const type_index& __rhs) const noexcept
+    {
+      if (*_M_target == *__rhs._M_target)
+	return strong_ordering::equal;
+      if (_M_target->before(*__rhs._M_target))
+	return strong_ordering::less;
+      return strong_ordering::greater;
+    }
+#endif
+
+    size_t
+    hash_code() const noexcept
+    { return _M_target->hash_code(); }
+
+    const char*
+    name() const noexcept
+    { return _M_target->name(); }
+
+  private:
+    const type_info* _M_target;
+  };
+
+  template<typename _Tp> struct hash;
+
+  /// std::hash specialization for type_index.
+  template<>
+    struct hash<type_index>
+    {
+      typedef size_t        result_type;
+      typedef type_index  argument_type;
+
+      size_t
+      operator()(const type_index& __ti) const noexcept
+      { return __ti.hash_code(); }
+    };
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif  // C++11
+
+#endif  // _GLIBCXX_TYPEINDEX
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@@ -0,0 +1,255 @@
+// RTTI support for -*- C++ -*-
+// Copyright (C) 1994-2022 Free Software Foundation, Inc.
+//
+// This file is part of GCC.
+//
+// GCC is free software; you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation; either version 3, or (at your option)
+// any later version.
+//
+// GCC is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file typeinfo
+ *  This is a Standard C++ Library header.
+ */
+
+#ifndef _TYPEINFO
+#define _TYPEINFO
+
+#pragma GCC system_header
+
+#include <bits/exception.h>
+#if __cplusplus >= 201103L
+#include <bits/hash_bytes.h>
+#endif
+
+#pragma GCC visibility push(default)
+
+#if __cplusplus >= 202100L
+# define __cpp_lib_constexpr_typeinfo 202106L
+#endif
+
+extern "C++" {
+
+namespace __cxxabiv1
+{
+  class __class_type_info;
+} // namespace __cxxabiv1
+
+// Determine whether typeinfo names for the same type are merged (in which
+// case comparison can just compare pointers) or not (in which case strings
+// must be compared), and whether comparison is to be implemented inline or
+// not.  We used to do inline pointer comparison by default if weak symbols
+// are available, but even with weak symbols sometimes names are not merged
+// when objects are loaded with RTLD_LOCAL, so now we always use strcmp by
+// default.  For ABI compatibility, we do the strcmp inline if weak symbols
+// are available, and out-of-line if not.  Out-of-line pointer comparison
+// is used where the object files are to be portable to multiple systems,
+// some of which may not be able to use pointer comparison, but the
+// particular system for which libstdc++ is being built can use pointer
+// comparison; in particular for most ARM EABI systems, where the ABI
+// specifies out-of-line comparison.  The compiler's target configuration
+// can override the defaults by defining __GXX_TYPEINFO_EQUALITY_INLINE to
+// 1 or 0 to indicate whether or not comparison is inline, and
+// __GXX_MERGED_TYPEINFO_NAMES to 1 or 0 to indicate whether or not pointer
+// comparison can be used.
+
+#ifndef __GXX_MERGED_TYPEINFO_NAMES
+// By default, typeinfo names are not merged.
+#define __GXX_MERGED_TYPEINFO_NAMES 0
+#endif
+
+// By default follow the old inline rules to avoid ABI changes.
+#ifndef __GXX_TYPEINFO_EQUALITY_INLINE
+  #if !__GXX_WEAK__
+    #define __GXX_TYPEINFO_EQUALITY_INLINE 0
+  #else
+    #define __GXX_TYPEINFO_EQUALITY_INLINE 1
+  #endif
+#endif
+
+namespace std
+{
+  /**
+   *  @brief  Part of RTTI.
+   *
+   *  The @c type_info class describes type information generated by
+   *  an implementation.
+  */
+  class type_info
+  {
+  public:
+    /** Destructor first. Being the first non-inline virtual function, this
+     *  controls in which translation unit the vtable is emitted. The
+     *  compiler makes use of that information to know where to emit
+     *  the runtime-mandated type_info structures in the new-abi.  */
+    virtual ~type_info();
+
+    /** Returns an @e implementation-defined byte string; this is not
+     *  portable between compilers!  */
+    const char* name() const _GLIBCXX_NOEXCEPT
+    { return __name[0] == '*' ? __name + 1 : __name; }
+
+    /** Returns true if `*this` precedes `__arg` in the implementation's
+     *  collation order.  */
+    bool before(const type_info& __arg) const _GLIBCXX_NOEXCEPT;
+
+    _GLIBCXX23_CONSTEXPR
+    bool operator==(const type_info& __arg) const _GLIBCXX_NOEXCEPT;
+
+#if __cpp_impl_three_way_comparison < 201907L
+    bool operator!=(const type_info& __arg) const _GLIBCXX_NOEXCEPT
+    { return !operator==(__arg); }
+#endif
+
+#if __cplusplus >= 201103L
+    size_t hash_code() const noexcept
+    {
+#  if !__GXX_MERGED_TYPEINFO_NAMES
+      return _Hash_bytes(name(), __builtin_strlen(name()),
+			 static_cast<size_t>(0xc70f6907UL));
+#  else
+      return reinterpret_cast<size_t>(__name);
+#  endif
+    }
+#endif // C++11
+
+    // Return true if this is a pointer type of some kind
+    virtual bool __is_pointer_p() const;
+
+    // Return true if this is a function type
+    virtual bool __is_function_p() const;
+
+    // Try and catch a thrown type. Store an adjusted pointer to the
+    // caught type in THR_OBJ. If THR_TYPE is not a pointer type, then
+    // THR_OBJ points to the thrown object. If THR_TYPE is a pointer
+    // type, then THR_OBJ is the pointer itself. OUTER indicates the
+    // number of outer pointers, and whether they were const
+    // qualified.
+    virtual bool __do_catch(const type_info *__thr_type, void **__thr_obj,
+			    unsigned __outer) const;
+
+    // Internally used during catch matching
+    virtual bool __do_upcast(const __cxxabiv1::__class_type_info *__target,
+			     void **__obj_ptr) const;
+
+  protected:
+    const char *__name;
+
+    explicit type_info(const char *__n): __name(__n) { }
+
+  private:
+    // type_info objects cannot be copied.
+#if __cplusplus >= 201103L
+    type_info& operator=(const type_info&) = delete;
+    type_info(const type_info&) = delete;
+#else
+    type_info& operator=(const type_info&);
+    type_info(const type_info&);
+#endif
+
+#if ! __GXX_TYPEINFO_EQUALITY_INLINE
+    bool __equal(const type_info&) const _GLIBCXX_NOEXCEPT;
+#endif
+  };
+
+#if __GXX_TYPEINFO_EQUALITY_INLINE
+  inline bool
+  type_info::before(const type_info& __arg) const _GLIBCXX_NOEXCEPT
+  {
+#if !__GXX_MERGED_TYPEINFO_NAMES
+    // Even with the new abi, on systems that support dlopen
+    // we can run into cases where type_info names aren't merged,
+    // so we still need to do string comparison.
+    if (__name[0] != '*' || __arg.__name[0] != '*')
+      return __builtin_strcmp (__name, __arg.__name) < 0;
+#else
+    // On some targets we can rely on type_info's NTBS being unique,
+    // and therefore address comparisons are sufficient.
+#endif
+
+    // In old abi, or when weak symbols are not supported, there can
+    // be multiple instances of a type_info object for one
+    // type. Uniqueness must use the __name value, not object address.
+    return __name < __arg.__name;
+  }
+#endif
+
+#if __GXX_TYPEINFO_EQUALITY_INLINE || __cplusplus > 202002L
+  _GLIBCXX23_CONSTEXPR inline bool
+  type_info::operator==(const type_info& __arg) const _GLIBCXX_NOEXCEPT
+  {
+    if (std::__is_constant_evaluated())
+      return this == &__arg;
+
+    if (__name == __arg.__name)
+      return true;
+
+#if !__GXX_TYPEINFO_EQUALITY_INLINE
+    // ABI requires comparisons to be non-inline.
+    return __equal(__arg);
+#elif !__GXX_MERGED_TYPEINFO_NAMES
+    // Need to do string comparison.
+    return __name[0] != '*' && __builtin_strcmp (__name, __arg.name()) == 0;
+#else
+    return false;
+#endif
+  }
+# endif
+
+
+  /**
+   *  @brief  Thrown during incorrect typecasting.
+   *  @ingroup exceptions
+   *
+   *  If you attempt an invalid @c dynamic_cast expression, an instance of
+   *  this class (or something derived from this class) is thrown.  */
+  class bad_cast : public exception
+  {
+  public:
+    bad_cast() _GLIBCXX_USE_NOEXCEPT { }
+
+    // This declaration is not useless:
+    // http://gcc.gnu.org/onlinedocs/gcc-3.0.2/gcc_6.html#SEC118
+    virtual ~bad_cast() _GLIBCXX_USE_NOEXCEPT;
+
+    // See comment in eh_exception.cc.
+    virtual const char* what() const _GLIBCXX_USE_NOEXCEPT;
+  };
+
+  /**
+   *  @brief Thrown when a NULL pointer in a @c typeid expression is used.
+   *  @ingroup exceptions
+   */
+  class bad_typeid : public exception
+  {
+  public:
+    bad_typeid () _GLIBCXX_USE_NOEXCEPT { }
+
+    // This declaration is not useless:
+    // http://gcc.gnu.org/onlinedocs/gcc-3.0.2/gcc_6.html#SEC118
+    virtual ~bad_typeid() _GLIBCXX_USE_NOEXCEPT;
+
+    // See comment in eh_exception.cc.
+    virtual const char* what() const _GLIBCXX_USE_NOEXCEPT;
+  };
+} // namespace std
+
+} // extern "C++"
+
+#pragma GCC visibility pop
+
+#endif
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index 0000000000000000000000000000000000000000..bb14ffa7f2e55ab6ee47ddbe88357b454b8763d1
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@unordered_map
@@ -0,0 +1,109 @@
+// <unordered_map> -*- C++ -*-
+
+// Copyright (C) 2007-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file include/unordered_map
+ *  This is a Standard C++ Library header.
+ */
+
+#ifndef _GLIBCXX_UNORDERED_MAP
+#define _GLIBCXX_UNORDERED_MAP 1
+
+#pragma GCC system_header
+
+#if __cplusplus < 201103L
+# include <bits/c++0x_warning.h>
+#else
+
+#include <type_traits>
+#include <initializer_list>
+#include <bits/allocator.h>
+#include <ext/alloc_traits.h>
+#include <ext/aligned_buffer.h>
+#include <bits/stl_pair.h>
+#include <bits/stl_function.h> // equal_to, _Identity, _Select1st
+#include <bits/functional_hash.h>
+#include <bits/hashtable.h>
+#include <bits/unordered_map.h>
+#include <bits/range_access.h>
+#include <bits/erase_if.h>
+
+#ifdef _GLIBCXX_DEBUG
+# include <debug/unordered_map>
+#endif
+
+#if __cplusplus >= 201703L
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+  namespace pmr
+  {
+    template<typename _Tp> class polymorphic_allocator;
+    template<typename _Key, typename _Tp, typename _Hash = std::hash<_Key>,
+	     typename _Pred = std::equal_to<_Key>>
+      using unordered_map
+	= std::unordered_map<_Key, _Tp, _Hash, _Pred,
+			     polymorphic_allocator<pair<const _Key, _Tp>>>;
+    template<typename _Key, typename _Tp, typename _Hash = std::hash<_Key>,
+	     typename _Pred = std::equal_to<_Key>>
+      using unordered_multimap
+	= std::unordered_multimap<_Key, _Tp, _Hash, _Pred,
+				  polymorphic_allocator<pair<const _Key, _Tp>>>;
+  } // namespace pmr
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+#endif // C++17
+
+#if __cplusplus > 201703L
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+  template<typename _Key, typename _Tp, typename _Hash, typename _CPred,
+	   typename _Alloc, typename _Predicate>
+    inline typename unordered_map<_Key, _Tp, _Hash, _CPred, _Alloc>::size_type
+    erase_if(unordered_map<_Key, _Tp, _Hash, _CPred, _Alloc>& __cont,
+	     _Predicate __pred)
+    {
+      const _GLIBCXX_STD_C::unordered_map<_Key, _Tp, _Hash, _CPred, _Alloc>&
+	__ucont = __cont;
+      return __detail::__erase_nodes_if(__cont, __ucont, __pred);
+    }
+
+  template<typename _Key, typename _Tp, typename _Hash, typename _CPred,
+	   typename _Alloc, typename _Predicate>
+    inline typename unordered_multimap<_Key, _Tp, _Hash, _CPred, _Alloc>::
+		    size_type
+    erase_if(unordered_multimap<_Key, _Tp, _Hash, _CPred, _Alloc>& __cont,
+	     _Predicate __pred)
+    {
+      const _GLIBCXX_STD_C::unordered_multimap<_Key, _Tp, _Hash, _CPred, _Alloc>&
+	__ucont = __cont;
+      return __detail::__erase_nodes_if(__cont, __ucont, __pred);
+    }
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+#endif // C++20
+
+#endif // C++11
+
+#endif // _GLIBCXX_UNORDERED_MAP
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@unordered_set b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@unordered_set
new file mode 100644
index 0000000000000000000000000000000000000000..777e3b8111628519bd5afd186e8d9508b00f889a
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@unordered_set
@@ -0,0 +1,108 @@
+// <unordered_set> -*- C++ -*-
+
+// Copyright (C) 2007-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file include/unordered_set
+ *  This is a Standard C++ Library header.
+ */
+
+#ifndef _GLIBCXX_UNORDERED_SET
+#define _GLIBCXX_UNORDERED_SET 1
+
+#pragma GCC system_header
+
+#if __cplusplus < 201103L
+# include <bits/c++0x_warning.h>
+#else
+
+#include <type_traits>
+#include <initializer_list>
+#include <bits/allocator.h>
+#include <ext/alloc_traits.h>
+#include <ext/aligned_buffer.h>
+#include <bits/stl_pair.h>
+#include <bits/stl_function.h> // equal_to, _Identity, _Select1st
+#include <bits/functional_hash.h>
+#include <bits/hashtable.h>
+#include <bits/unordered_set.h>
+#include <bits/range_access.h>
+#include <bits/erase_if.h>
+
+#ifdef _GLIBCXX_DEBUG
+# include <debug/unordered_set>
+#endif
+
+#if __cplusplus >= 201703L
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+  namespace pmr
+  {
+    template<typename _Tp> class polymorphic_allocator;
+    template<typename _Key, typename _Hash = std::hash<_Key>,
+	     typename _Pred = std::equal_to<_Key>>
+      using unordered_set
+	= std::unordered_set<_Key, _Hash, _Pred,
+			     polymorphic_allocator<_Key>>;
+    template<typename _Key, typename _Hash = std::hash<_Key>,
+	     typename _Pred = std::equal_to<_Key>>
+      using unordered_multiset
+	= std::unordered_multiset<_Key, _Hash, _Pred,
+				  polymorphic_allocator<_Key>>;
+  } // namespace pmr
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+#endif // C++17
+
+#if __cplusplus > 201703L
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+  template<typename _Key, typename _Hash, typename _CPred, typename _Alloc,
+	   typename _Predicate>
+    inline typename unordered_set<_Key, _Hash, _CPred, _Alloc>::size_type
+    erase_if(unordered_set<_Key, _Hash, _CPred, _Alloc>& __cont,
+	     _Predicate __pred)
+    {
+      const _GLIBCXX_STD_C::unordered_set<_Key, _Hash, _CPred, _Alloc>&
+	__ucont = __cont;
+      return __detail::__erase_nodes_if(__cont, __ucont, __pred);
+    }
+
+  template<typename _Key, typename _Hash, typename _CPred, typename _Alloc,
+	   typename _Predicate>
+    inline typename unordered_multiset<_Key, _Hash, _CPred, _Alloc>::size_type
+    erase_if(unordered_multiset<_Key, _Hash, _CPred, _Alloc>& __cont,
+	     _Predicate __pred)
+    {
+      const _GLIBCXX_STD_C::unordered_multiset<_Key, _Hash, _CPred, _Alloc>&
+	__ucont = __cont;
+      return __detail::__erase_nodes_if(__cont, __ucont, __pred);
+    }
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+#endif // C++20
+
+#endif // C++11
+
+#endif // _GLIBCXX_UNORDERED_SET
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@utility b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@utility
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--- /dev/null
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@@ -0,0 +1,225 @@
+// <utility> -*- C++ -*-
+
+// Copyright (C) 2001-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/*
+ *
+ * Copyright (c) 1994
+ * Hewlett-Packard Company
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Hewlett-Packard Company makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ *
+ *
+ * Copyright (c) 1996,1997
+ * Silicon Graphics Computer Systems, Inc.
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Silicon Graphics makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ */
+
+/** @file include/utility
+ *  This is a Standard C++ Library header.
+ */
+
+#ifndef _GLIBCXX_UTILITY
+#define _GLIBCXX_UTILITY 1
+
+#pragma GCC system_header
+
+/**
+ * @defgroup utilities Utilities
+ *
+ * Basic function and class templates used with the rest of the library.
+ * Includes pair, swap, forward/move helpers, declval, integer_sequence.
+ */
+
+#include <bits/c++config.h>
+#include <bits/stl_relops.h>
+#include <bits/stl_pair.h>
+
+#if __cplusplus >= 201103L
+
+#include <initializer_list>
+#include <type_traits>
+#include <bits/move.h>
+#include <bits/utility.h>
+
+#if __cplusplus >= 202002L
+#include <ext/numeric_traits.h> // __is_standard_integer, __int_traits
+#endif
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+#if __cplusplus >= 201402L
+#define __cpp_lib_exchange_function 201304L
+
+  /// Assign @p __new_val to @p __obj and return its previous value.
+  template <typename _Tp, typename _Up = _Tp>
+    _GLIBCXX20_CONSTEXPR
+    inline _Tp
+    exchange(_Tp& __obj, _Up&& __new_val)
+    noexcept(__and_<is_nothrow_move_constructible<_Tp>,
+		    is_nothrow_assignable<_Tp&, _Up>>::value)
+    { return std::__exchange(__obj, std::forward<_Up>(__new_val)); }
+
+#if __cplusplus >= 201703L
+
+#define  __cpp_lib_as_const 201510L
+  template<typename _Tp>
+    [[nodiscard]]
+    constexpr add_const_t<_Tp>&
+    as_const(_Tp& __t) noexcept
+    { return __t; }
+
+  template<typename _Tp>
+    void as_const(const _Tp&&) = delete;
+
+#if __cplusplus > 201703L
+#define __cpp_lib_integer_comparison_functions 202002L
+
+  template<typename _Tp, typename _Up>
+    constexpr bool
+    cmp_equal(_Tp __t, _Up __u) noexcept
+    {
+      static_assert(__is_standard_integer<_Tp>::value);
+      static_assert(__is_standard_integer<_Up>::value);
+
+      if constexpr (is_signed_v<_Tp> == is_signed_v<_Up>)
+	return __t == __u;
+      else if constexpr (is_signed_v<_Tp>)
+	return __t >= 0 && make_unsigned_t<_Tp>(__t) == __u;
+      else
+	return __u >= 0 && __t == make_unsigned_t<_Up>(__u);
+    }
+
+  template<typename _Tp, typename _Up>
+    constexpr bool
+    cmp_not_equal(_Tp __t, _Up __u) noexcept
+    { return !std::cmp_equal(__t, __u); }
+
+  template<typename _Tp, typename _Up>
+    constexpr bool
+    cmp_less(_Tp __t, _Up __u) noexcept
+    {
+      static_assert(__is_standard_integer<_Tp>::value);
+      static_assert(__is_standard_integer<_Up>::value);
+
+      if constexpr (is_signed_v<_Tp> == is_signed_v<_Up>)
+	return __t < __u;
+      else if constexpr (is_signed_v<_Tp>)
+	return __t < 0 || make_unsigned_t<_Tp>(__t) < __u;
+      else
+	return __u >= 0 && __t < make_unsigned_t<_Up>(__u);
+    }
+
+  template<typename _Tp, typename _Up>
+    constexpr bool
+    cmp_greater(_Tp __t, _Up __u) noexcept
+    { return std::cmp_less(__u, __t); }
+
+  template<typename _Tp, typename _Up>
+    constexpr bool
+    cmp_less_equal(_Tp __t, _Up __u) noexcept
+    { return !std::cmp_less(__u, __t); }
+
+  template<typename _Tp, typename _Up>
+    constexpr bool
+    cmp_greater_equal(_Tp __t, _Up __u) noexcept
+    { return !std::cmp_less(__t, __u); }
+
+  template<typename _Up, typename _Tp>
+    constexpr bool
+    in_range(_Tp __t) noexcept
+    {
+      static_assert(__is_standard_integer<_Up>::value);
+      static_assert(__is_standard_integer<_Tp>::value);
+      using __gnu_cxx::__int_traits;
+
+      if constexpr (is_signed_v<_Tp> == is_signed_v<_Up>)
+	return __int_traits<_Up>::__min <= __t
+	  && __t <= __int_traits<_Up>::__max;
+      else if constexpr (is_signed_v<_Tp>)
+	return __t >= 0
+	  && make_unsigned_t<_Tp>(__t) <= __int_traits<_Up>::__max;
+      else
+	return __t <= make_unsigned_t<_Up>(__int_traits<_Up>::__max);
+    }
+
+#if __cplusplus > 202002L
+#define __cpp_lib_to_underlying 202102L
+  /// Convert an object of enumeration type to its underlying type.
+  template<typename _Tp>
+    [[nodiscard]]
+    constexpr underlying_type_t<_Tp>
+    to_underlying(_Tp __value) noexcept
+    { return static_cast<underlying_type_t<_Tp>>(__value); }
+
+#define __cpp_lib_unreachable 202202L
+  /// Informs the compiler that program control flow never reaches this point.
+  /**
+   * Evaluating a call to this function results in undefined behaviour.
+   * This can be used as an assertion informing the compiler that certain
+   * conditions are impossible, for when the compiler is unable to determine
+   * that by itself.
+   *
+   * For example, it can be used to prevent warnings about reaching the
+   * end of a non-void function without returning.
+   *
+   * @since C++23
+   */
+  [[noreturn,__gnu__::__always_inline__]]
+  inline void
+  unreachable()
+  {
+#ifdef _GLIBCXX_DEBUG
+    std::__glibcxx_assert_fail(nullptr, 0, "std::unreachable()", nullptr);
+#elif defined _GLIBCXX_ASSERTIONS
+    __builtin_trap();
+#else
+    __builtin_unreachable();
+#endif
+  }
+#endif // C++23
+#endif // C++20
+#endif // C++17
+#endif // C++14
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif
+
+#endif /* _GLIBCXX_UTILITY */
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@@ -0,0 +1,1267 @@
+// The template and inlines for the -*- C++ -*- valarray class.
+
+// Copyright (C) 1997-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file include/valarray
+ *  This is a Standard C++ Library header.
+ */
+
+// Written by Gabriel Dos Reis <Gabriel.Dos-Reis@DPTMaths.ENS-Cachan.Fr>
+
+#ifndef _GLIBCXX_VALARRAY
+#define _GLIBCXX_VALARRAY 1
+
+#pragma GCC system_header
+
+#include <bits/c++config.h>
+#include <cmath>
+#include <algorithm>
+#include <debug/debug.h>
+#if __cplusplus >= 201103L
+#include <initializer_list>
+#endif
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  template<class _Clos, typename _Tp>
+    class _Expr;
+
+  template<typename _Tp1, typename _Tp2>
+    class _ValArray;
+
+namespace __detail
+{
+  template<class _Oper, template<class, class> class _Meta, class _Dom>
+    struct _UnClos;
+
+  template<class _Oper,
+        template<class, class> class _Meta1,
+        template<class, class> class _Meta2,
+        class _Dom1, class _Dom2>
+    class _BinClos;
+
+  template<template<class, class> class _Meta, class _Dom>
+    class _SClos;
+
+  template<template<class, class> class _Meta, class _Dom>
+    class _GClos;
+
+  template<template<class, class> class _Meta, class _Dom>
+    class _IClos;
+
+  template<template<class, class> class _Meta, class _Dom>
+    class _ValFunClos;
+
+  template<template<class, class> class _Meta, class _Dom>
+    class _RefFunClos;
+} // namespace __detail
+
+  using __detail::_UnClos;
+  using __detail::_BinClos;
+  using __detail::_SClos;
+  using __detail::_GClos;
+  using __detail::_IClos;
+  using __detail::_ValFunClos;
+  using __detail::_RefFunClos;
+
+  template<class _Tp> class valarray;   // An array of type _Tp
+  class slice;                          // BLAS-like slice out of an array
+  template<class _Tp> class slice_array;
+  class gslice;                         // generalized slice out of an array
+  template<class _Tp> class gslice_array;
+  template<class _Tp> class mask_array;     // masked array
+  template<class _Tp> class indirect_array; // indirected array
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#include <bits/valarray_array.h>
+#include <bits/valarray_before.h>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /**
+   * @defgroup numeric_arrays Numeric Arrays
+   * @ingroup numerics
+   *
+   * Classes and functions for representing and manipulating arrays of elements.
+   * @{
+   */
+
+  /**
+   *  @brief  Smart array designed to support numeric processing.
+   *
+   *  A valarray is an array that provides constraints intended to allow for
+   *  effective optimization of numeric array processing by reducing the
+   *  aliasing that can result from pointer representations.  It represents a
+   *  one-dimensional array from which different multidimensional subsets can
+   *  be accessed and modified.
+   *
+   *  @tparam  _Tp  Type of object in the array.
+   */
+  template<class _Tp>
+    class valarray
+    {
+      template<class _Op>
+	struct _UnaryOp
+	{
+	  typedef typename __fun<_Op, _Tp>::result_type __rt;
+	  typedef _Expr<_UnClos<_Op, _ValArray, _Tp>, __rt> _Rt;
+	};
+    public:
+      typedef _Tp value_type;
+
+	// _lib.valarray.cons_ construct/destroy:
+      ///  Construct an empty array.
+      valarray() _GLIBCXX_NOTHROW;
+
+      ///  Construct an array with @a n elements.
+      explicit valarray(size_t);
+
+      ///  Construct an array with @a n elements initialized to @a t.
+      valarray(const _Tp&, size_t);
+
+      ///  Construct an array initialized to the first @a n elements of @a t.
+      valarray(const _Tp* __restrict__, size_t);
+
+      ///  Copy constructor.
+      valarray(const valarray&);
+
+#if __cplusplus >= 201103L
+      ///  Move constructor.
+      valarray(valarray&&) noexcept;
+#endif
+
+      ///  Construct an array with the same size and values in @a sa.
+      valarray(const slice_array<_Tp>&);
+
+      ///  Construct an array with the same size and values in @a ga.
+      valarray(const gslice_array<_Tp>&);
+
+      ///  Construct an array with the same size and values in @a ma.
+      valarray(const mask_array<_Tp>&);
+
+      ///  Construct an array with the same size and values in @a ia.
+      valarray(const indirect_array<_Tp>&);
+
+#if __cplusplus >= 201103L
+      ///  Construct an array with an initializer_list of values.
+      valarray(initializer_list<_Tp>);
+#endif
+
+      template<class _Dom>
+	valarray(const _Expr<_Dom, _Tp>& __e);
+
+      ~valarray() _GLIBCXX_NOEXCEPT;
+
+      // _lib.valarray.assign_ assignment:
+      /**
+       *  @brief  Assign elements to an array.
+       *
+       *  Assign elements of array to values in @a v.
+       *
+       *  @param  __v  Valarray to get values from.
+       */
+      valarray<_Tp>& operator=(const valarray<_Tp>& __v);
+
+#if __cplusplus >= 201103L
+      /**
+       *  @brief  Move assign elements to an array.
+       *
+       *  Move assign elements of array to values in @a v.
+       *
+       *  @param  __v  Valarray to get values from.
+       */
+      valarray<_Tp>& operator=(valarray<_Tp>&& __v) noexcept;
+#endif
+
+      /**
+       *  @brief  Assign elements to a value.
+       *
+       *  Assign all elements of array to @a t.
+       *
+       *  @param  __t  Value for elements.
+       */
+      valarray<_Tp>& operator=(const _Tp& __t);
+
+      /**
+       *  @brief  Assign elements to an array subset.
+       *
+       *  Assign elements of array to values in @a sa.  Results are undefined
+       *  if @a sa does not have the same size as this array.
+       *
+       *  @param  __sa  Array slice to get values from.
+       */
+      valarray<_Tp>& operator=(const slice_array<_Tp>& __sa);
+
+      /**
+       *  @brief  Assign elements to an array subset.
+       *
+       *  Assign elements of array to values in @a ga.  Results are undefined
+       *  if @a ga does not have the same size as this array.
+       *
+       *  @param  __ga  Array slice to get values from.
+       */
+      valarray<_Tp>& operator=(const gslice_array<_Tp>& __ga);
+
+      /**
+       *  @brief  Assign elements to an array subset.
+       *
+       *  Assign elements of array to values in @a ma.  Results are undefined
+       *  if @a ma does not have the same size as this array.
+       *
+       *  @param  __ma  Array slice to get values from.
+       */
+      valarray<_Tp>& operator=(const mask_array<_Tp>& __ma);
+
+      /**
+       *  @brief  Assign elements to an array subset.
+       *
+       *  Assign elements of array to values in @a ia.  Results are undefined
+       *  if @a ia does not have the same size as this array.
+       *
+       *  @param  __ia  Array slice to get values from.
+       */
+      valarray<_Tp>& operator=(const indirect_array<_Tp>& __ia);
+
+#if __cplusplus >= 201103L
+      /**
+       *  @brief  Assign elements to an initializer_list.
+       *
+       *  Assign elements of array to values in @a __l.  Results are undefined
+       *  if @a __l does not have the same size as this array.
+       *
+       *  @param  __l  initializer_list to get values from.
+       */
+      valarray& operator=(initializer_list<_Tp> __l);
+#endif
+
+      template<class _Dom> valarray<_Tp>&
+	operator= (const _Expr<_Dom, _Tp>&);
+
+      // _lib.valarray.access_ element access:
+      /**
+       *  Return a reference to the i'th array element.
+       *
+       *  @param  __i  Index of element to return.
+       *  @return  Reference to the i'th element.
+       */
+      _Tp&                operator[](size_t __i) _GLIBCXX_NOTHROW;
+
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 389. Const overload of valarray::operator[] returns by value.
+      const _Tp&          operator[](size_t) const _GLIBCXX_NOTHROW;
+
+      // _lib.valarray.sub_ subset operations:
+      /**
+       *  @brief  Return an array subset.
+       *
+       *  Returns a new valarray containing the elements of the array
+       *  indicated by the slice argument.  The new valarray has the same size
+       *  as the input slice.  @see slice.
+       *
+       *  @param  __s  The source slice.
+       *  @return  New valarray containing elements in @a __s.
+       */
+      _Expr<_SClos<_ValArray, _Tp>, _Tp> operator[](slice __s) const;
+
+      /**
+       *  @brief  Return a reference to an array subset.
+       *
+       *  Returns a new valarray containing the elements of the array
+       *  indicated by the slice argument.  The new valarray has the same size
+       *  as the input slice.  @see slice.
+       *
+       *  @param  __s  The source slice.
+       *  @return  New valarray containing elements in @a __s.
+       */
+      slice_array<_Tp>    operator[](slice __s);
+
+      /**
+       *  @brief  Return an array subset.
+       *
+       *  Returns a slice_array referencing the elements of the array
+       *  indicated by the slice argument.  @see gslice.
+       *
+       *  @param  __s  The source slice.
+       *  @return  Slice_array referencing elements indicated by @a __s.
+       */
+      _Expr<_GClos<_ValArray, _Tp>, _Tp> operator[](const gslice& __s) const;
+
+      /**
+       *  @brief  Return a reference to an array subset.
+       *
+       *  Returns a new valarray containing the elements of the array
+       *  indicated by the gslice argument.  The new valarray has
+       *  the same size as the input gslice.  @see gslice.
+       *
+       *  @param  __s  The source gslice.
+       *  @return  New valarray containing elements in @a __s.
+       */
+      gslice_array<_Tp>   operator[](const gslice& __s);
+
+      /**
+       *  @brief  Return an array subset.
+       *
+       *  Returns a new valarray containing the elements of the array
+       *  indicated by the argument.  The input is a valarray of bool which
+       *  represents a bitmask indicating which elements should be copied into
+       *  the new valarray.  Each element of the array is added to the return
+       *  valarray if the corresponding element of the argument is true.
+       *
+       *  @param  __m  The valarray bitmask.
+       *  @return  New valarray containing elements indicated by @a __m.
+       */
+      valarray<_Tp>       operator[](const valarray<bool>& __m) const;
+
+      /**
+       *  @brief  Return a reference to an array subset.
+       *
+       *  Returns a new mask_array referencing the elements of the array
+       *  indicated by the argument.  The input is a valarray of bool which
+       *  represents a bitmask indicating which elements are part of the
+       *  subset.  Elements of the array are part of the subset if the
+       *  corresponding element of the argument is true.
+       *
+       *  @param  __m  The valarray bitmask.
+       *  @return  New valarray containing elements indicated by @a __m.
+       */
+      mask_array<_Tp>     operator[](const valarray<bool>& __m);
+
+      /**
+       *  @brief  Return an array subset.
+       *
+       *  Returns a new valarray containing the elements of the array
+       *  indicated by the argument.  The elements in the argument are
+       *  interpreted as the indices of elements of this valarray to copy to
+       *  the return valarray.
+       *
+       *  @param  __i  The valarray element index list.
+       *  @return  New valarray containing elements in @a __s.
+       */
+      _Expr<_IClos<_ValArray, _Tp>, _Tp>
+        operator[](const valarray<size_t>& __i) const;
+
+      /**
+       *  @brief  Return a reference to an array subset.
+       *
+       *  Returns an indirect_array referencing the elements of the array
+       *  indicated by the argument.  The elements in the argument are
+       *  interpreted as the indices of elements of this valarray to include
+       *  in the subset.  The returned indirect_array refers to these
+       *  elements.
+       *
+       *  @param  __i  The valarray element index list.
+       *  @return  Indirect_array referencing elements in @a __i.
+       */
+      indirect_array<_Tp> operator[](const valarray<size_t>& __i);
+
+      // _lib.valarray.unary_ unary operators:
+      ///  Return a new valarray by applying unary + to each element.
+      typename _UnaryOp<__unary_plus>::_Rt  operator+() const;
+
+      ///  Return a new valarray by applying unary - to each element.
+      typename _UnaryOp<__negate>::_Rt      operator-() const;
+
+      ///  Return a new valarray by applying unary ~ to each element.
+      typename _UnaryOp<__bitwise_not>::_Rt operator~() const;
+
+      ///  Return a new valarray by applying unary ! to each element.
+      typename _UnaryOp<__logical_not>::_Rt operator!() const;
+
+      // _lib.valarray.cassign_ computed assignment:
+      ///  Multiply each element of array by @a t.
+      valarray<_Tp>& operator*=(const _Tp&);
+
+      ///  Divide each element of array by @a t.
+      valarray<_Tp>& operator/=(const _Tp&);
+
+      ///  Set each element e of array to e % @a t.
+      valarray<_Tp>& operator%=(const _Tp&);
+
+      ///  Add @a t to each element of array.
+      valarray<_Tp>& operator+=(const _Tp&);
+
+      ///  Subtract @a t to each element of array.
+      valarray<_Tp>& operator-=(const _Tp&);
+
+      ///  Set each element e of array to e ^ @a t.
+      valarray<_Tp>& operator^=(const _Tp&);
+
+      ///  Set each element e of array to e & @a t.
+      valarray<_Tp>& operator&=(const _Tp&);
+
+      ///  Set each element e of array to e | @a t.
+      valarray<_Tp>& operator|=(const _Tp&);
+
+      ///  Left shift each element e of array by @a t bits.
+      valarray<_Tp>& operator<<=(const _Tp&);
+
+      ///  Right shift each element e of array by @a t bits.
+      valarray<_Tp>& operator>>=(const _Tp&);
+
+      ///  Multiply elements of array by corresponding elements of @a v.
+      valarray<_Tp>& operator*=(const valarray<_Tp>&);
+
+      ///  Divide elements of array by corresponding elements of @a v.
+      valarray<_Tp>& operator/=(const valarray<_Tp>&);
+
+      ///  Modulo elements of array by corresponding elements of @a v.
+      valarray<_Tp>& operator%=(const valarray<_Tp>&);
+
+      ///  Add corresponding elements of @a v to elements of array.
+      valarray<_Tp>& operator+=(const valarray<_Tp>&);
+
+      ///  Subtract corresponding elements of @a v from elements of array.
+      valarray<_Tp>& operator-=(const valarray<_Tp>&);
+
+      ///  Logical xor corresponding elements of @a v with elements of array.
+      valarray<_Tp>& operator^=(const valarray<_Tp>&);
+
+      ///  Logical or corresponding elements of @a v with elements of array.
+      valarray<_Tp>& operator|=(const valarray<_Tp>&);
+
+      ///  Logical and corresponding elements of @a v with elements of array.
+      valarray<_Tp>& operator&=(const valarray<_Tp>&);
+
+      ///  Left shift elements of array by corresponding elements of @a v.
+      valarray<_Tp>& operator<<=(const valarray<_Tp>&);
+
+      ///  Right shift elements of array by corresponding elements of @a v.
+      valarray<_Tp>& operator>>=(const valarray<_Tp>&);
+
+      template<class _Dom>
+	valarray<_Tp>& operator*=(const _Expr<_Dom, _Tp>&);
+      template<class _Dom>
+	valarray<_Tp>& operator/=(const _Expr<_Dom, _Tp>&);
+      template<class _Dom>
+	valarray<_Tp>& operator%=(const _Expr<_Dom, _Tp>&);
+      template<class _Dom>
+	valarray<_Tp>& operator+=(const _Expr<_Dom, _Tp>&);
+      template<class _Dom>
+	valarray<_Tp>& operator-=(const _Expr<_Dom, _Tp>&);
+      template<class _Dom>
+	valarray<_Tp>& operator^=(const _Expr<_Dom, _Tp>&);
+      template<class _Dom>
+	valarray<_Tp>& operator|=(const _Expr<_Dom, _Tp>&);
+      template<class _Dom>
+	valarray<_Tp>& operator&=(const _Expr<_Dom, _Tp>&);
+      template<class _Dom>
+        valarray<_Tp>& operator<<=(const _Expr<_Dom, _Tp>&);
+      template<class _Dom>
+	valarray<_Tp>& operator>>=(const _Expr<_Dom, _Tp>&);
+
+      // _lib.valarray.members_ member functions:
+#if __cplusplus >= 201103L
+      ///  Swap.
+      void swap(valarray<_Tp>& __v) noexcept;
+#endif
+
+      ///  Return the number of elements in array.
+      size_t size() const;
+
+      /**
+       *  @brief  Return the sum of all elements in the array.
+       *
+       *  Accumulates the sum of all elements into a Tp using +=.  The order
+       *  of adding the elements is unspecified.
+       */
+      _Tp    sum() const;
+
+      ///  Return the minimum element using operator<().
+      _Tp    min() const;
+
+      ///  Return the maximum element using operator<().
+      _Tp    max() const;
+
+      /**
+       *  @brief  Return a shifted array.
+       *
+       *  A new valarray is constructed as a copy of this array with elements
+       *  in shifted positions.  For an element with index i, the new position
+       *  is i - n.  The new valarray has the same size as the current one.
+       *  New elements without a value are set to 0.  Elements whose new
+       *  position is outside the bounds of the array are discarded.
+       *
+       *  Positive arguments shift toward index 0, discarding elements [0, n).
+       *  Negative arguments discard elements from the top of the array.
+       *
+       *  @param  __n  Number of element positions to shift.
+       *  @return  New valarray with elements in shifted positions.
+       */
+      valarray<_Tp> shift (int __n) const;
+
+      /**
+       *  @brief  Return a rotated array.
+       *
+       *  A new valarray is constructed as a copy of this array with elements
+       *  in shifted positions.  For an element with index i, the new position
+       *  is (i - n) % size().  The new valarray has the same size as the
+       *  current one.  Elements that are shifted beyond the array bounds are
+       *  shifted into the other end of the array.  No elements are lost.
+       *
+       *  Positive arguments shift toward index 0, wrapping around the top.
+       *  Negative arguments shift towards the top, wrapping around to 0.
+       *
+       *  @param  __n  Number of element positions to rotate.
+       *  @return  New valarray with elements in shifted positions.
+       */
+      valarray<_Tp> cshift(int __n) const;
+
+      /**
+       *  @brief  Apply a function to the array.
+       *
+       *  Returns a new valarray with elements assigned to the result of
+       *  applying __func to the corresponding element of this array.  The new
+       *  array has the same size as this one.
+       *
+       *  @param  __func  Function of Tp returning Tp to apply.
+       *  @return  New valarray with transformed elements.
+       */
+      _Expr<_ValFunClos<_ValArray, _Tp>, _Tp> apply(_Tp __func(_Tp)) const;
+
+      /**
+       *  @brief  Apply a function to the array.
+       *
+       *  Returns a new valarray with elements assigned to the result of
+       *  applying __func to the corresponding element of this array.  The new
+       *  array has the same size as this one.
+       *
+       *  @param  __func  Function of const Tp& returning Tp to apply.
+       *  @return  New valarray with transformed elements.
+       */
+      _Expr<_RefFunClos<_ValArray, _Tp>, _Tp> apply(_Tp __func(const _Tp&)) const;
+
+      /**
+       *  @brief  Resize array.
+       *
+       *  Resize this array to @a size and set all elements to @a c.  All
+       *  references and iterators are invalidated.
+       *
+       *  @param  __size  New array size.
+       *  @param  __c  New value for all elements.
+       */
+      void resize(size_t __size, _Tp __c = _Tp());
+
+    private:
+      size_t _M_size;
+      _Tp* __restrict__ _M_data;
+
+      friend struct _Array<_Tp>;
+    };
+
+#if __cpp_deduction_guides >= 201606
+  template<typename _Tp, size_t _Nm>
+    valarray(const _Tp(&)[_Nm], size_t) -> valarray<_Tp>;
+#endif
+
+  template<typename _Tp>
+    inline const _Tp&
+    valarray<_Tp>::operator[](size_t __i) const _GLIBCXX_NOTHROW
+    {
+      __glibcxx_requires_subscript(__i);
+      return _M_data[__i];
+    }
+
+  template<typename _Tp>
+    inline _Tp&
+    valarray<_Tp>::operator[](size_t __i) _GLIBCXX_NOTHROW
+    {
+      __glibcxx_requires_subscript(__i);
+      return _M_data[__i];
+    }
+
+  /// @} group numeric_arrays
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#include <bits/valarray_after.h>
+#include <bits/slice_array.h>
+#include <bits/gslice.h>
+#include <bits/gslice_array.h>
+#include <bits/mask_array.h>
+#include <bits/indirect_array.h>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /**
+   * @addtogroup numeric_arrays
+   * @{
+   */
+
+  template<typename _Tp>
+    inline
+    valarray<_Tp>::valarray() _GLIBCXX_NOTHROW : _M_size(0), _M_data(0) {}
+
+  template<typename _Tp>
+    inline
+    valarray<_Tp>::valarray(size_t __n)
+    : _M_size(__n), _M_data(__valarray_get_storage<_Tp>(__n))
+    { std::__valarray_default_construct(_M_data, _M_data + __n); }
+
+  template<typename _Tp>
+    inline
+    valarray<_Tp>::valarray(const _Tp& __t, size_t __n)
+    : _M_size(__n), _M_data(__valarray_get_storage<_Tp>(__n))
+    { std::__valarray_fill_construct(_M_data, _M_data + __n, __t); }
+
+  template<typename _Tp>
+    inline
+    valarray<_Tp>::valarray(const _Tp* __restrict__ __p, size_t __n)
+    : _M_size(__n), _M_data(__valarray_get_storage<_Tp>(__n))
+    {
+      __glibcxx_assert(__p != 0 || __n == 0);
+      std::__valarray_copy_construct(__p, __p + __n, _M_data);
+    }
+
+  template<typename _Tp>
+    inline
+    valarray<_Tp>::valarray(const valarray<_Tp>& __v)
+    : _M_size(__v._M_size), _M_data(__valarray_get_storage<_Tp>(__v._M_size))
+    { std::__valarray_copy_construct(__v._M_data, __v._M_data + _M_size,
+				     _M_data); }
+
+#if __cplusplus >= 201103L
+  template<typename _Tp>
+    inline
+    valarray<_Tp>::valarray(valarray<_Tp>&& __v) noexcept
+    : _M_size(__v._M_size), _M_data(__v._M_data)
+    {
+      __v._M_size = 0;
+      __v._M_data = 0;
+    }
+#endif
+
+  template<typename _Tp>
+    inline
+    valarray<_Tp>::valarray(const slice_array<_Tp>& __sa)
+    : _M_size(__sa._M_sz), _M_data(__valarray_get_storage<_Tp>(__sa._M_sz))
+    {
+      std::__valarray_copy_construct
+	(__sa._M_array, __sa._M_sz, __sa._M_stride, _Array<_Tp>(_M_data));
+    }
+
+  template<typename _Tp>
+    inline
+    valarray<_Tp>::valarray(const gslice_array<_Tp>& __ga)
+    : _M_size(__ga._M_index.size()),
+      _M_data(__valarray_get_storage<_Tp>(_M_size))
+    {
+      std::__valarray_copy_construct
+	(__ga._M_array, _Array<size_t>(__ga._M_index),
+	 _Array<_Tp>(_M_data), _M_size);
+    }
+
+  template<typename _Tp>
+    inline
+    valarray<_Tp>::valarray(const mask_array<_Tp>& __ma)
+    : _M_size(__ma._M_sz), _M_data(__valarray_get_storage<_Tp>(__ma._M_sz))
+    {
+      std::__valarray_copy_construct
+	(__ma._M_array, __ma._M_mask, _Array<_Tp>(_M_data), _M_size);
+    }
+
+  template<typename _Tp>
+    inline
+    valarray<_Tp>::valarray(const indirect_array<_Tp>& __ia)
+    : _M_size(__ia._M_sz), _M_data(__valarray_get_storage<_Tp>(__ia._M_sz))
+    {
+      std::__valarray_copy_construct
+	(__ia._M_array, __ia._M_index, _Array<_Tp>(_M_data), _M_size);
+    }
+
+#if __cplusplus >= 201103L
+  template<typename _Tp>
+    inline
+    valarray<_Tp>::valarray(initializer_list<_Tp> __l)
+    : _M_size(__l.size()), _M_data(__valarray_get_storage<_Tp>(__l.size()))
+    { std::__valarray_copy_construct(__l.begin(), __l.end(), _M_data); }
+#endif
+
+  template<typename _Tp> template<class _Dom>
+    inline
+    valarray<_Tp>::valarray(const _Expr<_Dom, _Tp>& __e)
+    : _M_size(__e.size()), _M_data(__valarray_get_storage<_Tp>(_M_size))
+    { std::__valarray_copy_construct(__e, _M_size, _Array<_Tp>(_M_data)); }
+
+  template<typename _Tp>
+    inline
+    valarray<_Tp>::~valarray() _GLIBCXX_NOEXCEPT
+    {
+      std::__valarray_destroy_elements(_M_data, _M_data + _M_size);
+      std::__valarray_release_memory(_M_data);
+    }
+
+  template<typename _Tp>
+    inline valarray<_Tp>&
+    valarray<_Tp>::operator=(const valarray<_Tp>& __v)
+    {
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 630. arrays of valarray.
+      if (_M_size == __v._M_size)
+	std::__valarray_copy(__v._M_data, _M_size, _M_data);
+      else
+	{
+	  if (_M_data)
+	    {
+	      std::__valarray_destroy_elements(_M_data, _M_data + _M_size);
+	      std::__valarray_release_memory(_M_data);
+	    }
+	  _M_size = __v._M_size;
+	  _M_data = __valarray_get_storage<_Tp>(_M_size);
+	  std::__valarray_copy_construct(__v._M_data, __v._M_data + _M_size,
+					 _M_data);
+	}
+      return *this;
+    }
+
+#if __cplusplus >= 201103L
+  template<typename _Tp>
+    inline valarray<_Tp>&
+    valarray<_Tp>::operator=(valarray<_Tp>&& __v) noexcept
+    {
+      if (_M_data)
+	{
+	  std::__valarray_destroy_elements(_M_data, _M_data + _M_size);
+	  std::__valarray_release_memory(_M_data);
+	}
+      _M_size = __v._M_size;
+      _M_data = __v._M_data;
+      __v._M_size = 0;
+      __v._M_data = 0;
+      return *this;
+    }
+
+  template<typename _Tp>
+    inline valarray<_Tp>&
+    valarray<_Tp>::operator=(initializer_list<_Tp> __l)
+    {
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 630. arrays of valarray.
+      if (_M_size == __l.size())
+	std::__valarray_copy(__l.begin(), __l.size(), _M_data);
+      else
+	{
+	  if (_M_data)
+	    {
+	      std::__valarray_destroy_elements(_M_data, _M_data + _M_size);
+	      std::__valarray_release_memory(_M_data);
+	    }
+	  _M_size = __l.size();
+	  _M_data = __valarray_get_storage<_Tp>(_M_size);
+	  std::__valarray_copy_construct(__l.begin(), __l.begin() + _M_size,
+					 _M_data);
+	}
+      return *this;
+    }
+#endif
+
+  template<typename _Tp>
+    inline valarray<_Tp>&
+    valarray<_Tp>::operator=(const _Tp& __t)
+    {
+      std::__valarray_fill(_M_data, _M_size, __t);
+      return *this;
+    }
+
+  template<typename _Tp>
+    inline valarray<_Tp>&
+    valarray<_Tp>::operator=(const slice_array<_Tp>& __sa)
+    {
+      __glibcxx_assert(_M_size == __sa._M_sz);
+      std::__valarray_copy(__sa._M_array, __sa._M_sz,
+			   __sa._M_stride, _Array<_Tp>(_M_data));
+      return *this;
+    }
+
+  template<typename _Tp>
+    inline valarray<_Tp>&
+    valarray<_Tp>::operator=(const gslice_array<_Tp>& __ga)
+    {
+      __glibcxx_assert(_M_size == __ga._M_index.size());
+      std::__valarray_copy(__ga._M_array, _Array<size_t>(__ga._M_index),
+			   _Array<_Tp>(_M_data), _M_size);
+      return *this;
+    }
+
+  template<typename _Tp>
+    inline valarray<_Tp>&
+    valarray<_Tp>::operator=(const mask_array<_Tp>& __ma)
+    {
+      __glibcxx_assert(_M_size == __ma._M_sz);
+      std::__valarray_copy(__ma._M_array, __ma._M_mask,
+			   _Array<_Tp>(_M_data), _M_size);
+      return *this;
+    }
+
+  template<typename _Tp>
+    inline valarray<_Tp>&
+    valarray<_Tp>::operator=(const indirect_array<_Tp>& __ia)
+    {
+      __glibcxx_assert(_M_size == __ia._M_sz);
+      std::__valarray_copy(__ia._M_array, __ia._M_index,
+			   _Array<_Tp>(_M_data), _M_size);
+      return *this;
+    }
+
+  template<typename _Tp> template<class _Dom>
+    inline valarray<_Tp>&
+    valarray<_Tp>::operator=(const _Expr<_Dom, _Tp>& __e)
+    {
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 630. arrays of valarray.
+      if (_M_size == __e.size())
+	std::__valarray_copy(__e, _M_size, _Array<_Tp>(_M_data));
+      else
+	{
+	  if (_M_data)
+	    {
+	      std::__valarray_destroy_elements(_M_data, _M_data + _M_size);
+	      std::__valarray_release_memory(_M_data);
+	    }
+	  _M_size = __e.size();
+	  _M_data = __valarray_get_storage<_Tp>(_M_size);
+	  std::__valarray_copy_construct(__e, _M_size, _Array<_Tp>(_M_data));
+	}
+      return *this;
+    }
+
+  template<typename _Tp>
+    inline _Expr<_SClos<_ValArray,_Tp>, _Tp>
+    valarray<_Tp>::operator[](slice __s) const
+    {
+      typedef _SClos<_ValArray,_Tp> _Closure;
+      return _Expr<_Closure, _Tp>(_Closure (_Array<_Tp>(_M_data), __s));
+    }
+
+  template<typename _Tp>
+    inline slice_array<_Tp>
+    valarray<_Tp>::operator[](slice __s)
+    { return slice_array<_Tp>(_Array<_Tp>(_M_data), __s); }
+
+  template<typename _Tp>
+    inline _Expr<_GClos<_ValArray,_Tp>, _Tp>
+    valarray<_Tp>::operator[](const gslice& __gs) const
+    {
+      typedef _GClos<_ValArray,_Tp> _Closure;
+      return _Expr<_Closure, _Tp>
+	(_Closure(_Array<_Tp>(_M_data), __gs._M_index->_M_index));
+    }
+
+  template<typename _Tp>
+    inline gslice_array<_Tp>
+    valarray<_Tp>::operator[](const gslice& __gs)
+    {
+      return gslice_array<_Tp>
+	(_Array<_Tp>(_M_data), __gs._M_index->_M_index);
+    }
+
+  template<typename _Tp>
+    inline valarray<_Tp>
+    valarray<_Tp>::operator[](const valarray<bool>& __m) const
+    {
+      size_t __s = 0;
+      size_t __e = __m.size();
+      for (size_t __i=0; __i<__e; ++__i)
+	if (__m[__i]) ++__s;
+      return valarray<_Tp>(mask_array<_Tp>(_Array<_Tp>(_M_data), __s,
+					   _Array<bool> (__m)));
+    }
+
+  template<typename _Tp>
+    inline mask_array<_Tp>
+    valarray<_Tp>::operator[](const valarray<bool>& __m)
+    {
+      size_t __s = 0;
+      size_t __e = __m.size();
+      for (size_t __i=0; __i<__e; ++__i)
+	if (__m[__i]) ++__s;
+      return mask_array<_Tp>(_Array<_Tp>(_M_data), __s, _Array<bool>(__m));
+    }
+
+  template<typename _Tp>
+    inline _Expr<_IClos<_ValArray,_Tp>, _Tp>
+    valarray<_Tp>::operator[](const valarray<size_t>& __i) const
+    {
+      typedef _IClos<_ValArray,_Tp> _Closure;
+      return _Expr<_Closure, _Tp>(_Closure(*this, __i));
+    }
+
+  template<typename _Tp>
+    inline indirect_array<_Tp>
+    valarray<_Tp>::operator[](const valarray<size_t>& __i)
+    {
+      return indirect_array<_Tp>(_Array<_Tp>(_M_data), __i.size(),
+				 _Array<size_t>(__i));
+    }
+
+#if __cplusplus >= 201103L
+  template<class _Tp>
+    inline void
+    valarray<_Tp>::swap(valarray<_Tp>& __v) noexcept
+    {
+      std::swap(_M_size, __v._M_size);
+      std::swap(_M_data, __v._M_data);
+    }
+#endif
+
+  template<class _Tp>
+    inline size_t
+    valarray<_Tp>::size() const
+    { return _M_size; }
+
+  template<class _Tp>
+    inline _Tp
+    valarray<_Tp>::sum() const
+    {
+      __glibcxx_assert(_M_size > 0);
+      return std::__valarray_sum(_M_data, _M_data + _M_size);
+    }
+
+  template<class _Tp>
+     inline valarray<_Tp>
+     valarray<_Tp>::shift(int __n) const
+     {
+       valarray<_Tp> __ret;
+
+       if (_M_size == 0)
+	 return __ret;
+
+       _Tp* __restrict__ __tmp_M_data =
+	 std::__valarray_get_storage<_Tp>(_M_size);
+
+       if (__n == 0)
+	 std::__valarray_copy_construct(_M_data,
+					_M_data + _M_size, __tmp_M_data);
+       else if (__n > 0)      // shift left
+	 {
+	   if (size_t(__n) > _M_size)
+	     __n = int(_M_size);
+
+	   std::__valarray_copy_construct(_M_data + __n,
+					  _M_data + _M_size, __tmp_M_data);
+	   std::__valarray_default_construct(__tmp_M_data + _M_size - __n,
+					     __tmp_M_data + _M_size);
+	 }
+       else                   // shift right
+	 {
+	   if (-size_t(__n) > _M_size)
+	     __n = -int(_M_size);
+
+	   std::__valarray_copy_construct(_M_data, _M_data + _M_size + __n,
+					  __tmp_M_data - __n);
+	   std::__valarray_default_construct(__tmp_M_data,
+					     __tmp_M_data - __n);
+	 }
+
+       __ret._M_size = _M_size;
+       __ret._M_data = __tmp_M_data;
+       return __ret;
+     }
+
+  template<class _Tp>
+     inline valarray<_Tp>
+     valarray<_Tp>::cshift(int __n) const
+     {
+       valarray<_Tp> __ret;
+
+       if (_M_size == 0)
+	 return __ret;
+
+       _Tp* __restrict__ __tmp_M_data =
+	 std::__valarray_get_storage<_Tp>(_M_size);
+
+       if (__n == 0)
+	 std::__valarray_copy_construct(_M_data,
+					_M_data + _M_size, __tmp_M_data);
+       else if (__n > 0)      // cshift left
+	 {
+	   if (size_t(__n) > _M_size)
+	     __n = int(__n % _M_size);
+
+	   std::__valarray_copy_construct(_M_data, _M_data + __n,
+					  __tmp_M_data + _M_size - __n);
+	   std::__valarray_copy_construct(_M_data + __n, _M_data + _M_size,
+					  __tmp_M_data);
+	 }
+       else                   // cshift right
+	 {
+	   if (-size_t(__n) > _M_size)
+	     __n = -int(-size_t(__n) % _M_size);
+
+	   std::__valarray_copy_construct(_M_data + _M_size + __n,
+					  _M_data + _M_size, __tmp_M_data);
+	   std::__valarray_copy_construct(_M_data, _M_data + _M_size + __n,
+					  __tmp_M_data - __n);
+	 }
+
+       __ret._M_size = _M_size;
+       __ret._M_data = __tmp_M_data;
+       return __ret;
+     }
+
+  template<class _Tp>
+    inline void
+    valarray<_Tp>::resize(size_t __n, _Tp __c)
+    {
+      // This complication is so to make valarray<valarray<T> > work
+      // even though it is not required by the standard.  Nobody should
+      // be saying valarray<valarray<T> > anyway.  See the specs.
+      std::__valarray_destroy_elements(_M_data, _M_data + _M_size);
+      if (_M_size != __n)
+	{
+	  std::__valarray_release_memory(_M_data);
+	  _M_size = __n;
+	  _M_data = __valarray_get_storage<_Tp>(__n);
+	}
+      std::__valarray_fill_construct(_M_data, _M_data + __n, __c);
+    }
+
+  template<typename _Tp>
+    inline _Tp
+    valarray<_Tp>::min() const
+    {
+      __glibcxx_assert(_M_size > 0);
+      return *std::min_element(_M_data, _M_data + _M_size);
+    }
+
+  template<typename _Tp>
+    inline _Tp
+    valarray<_Tp>::max() const
+    {
+      __glibcxx_assert(_M_size > 0);
+      return *std::max_element(_M_data, _M_data + _M_size);
+    }
+
+  template<class _Tp>
+    inline _Expr<_ValFunClos<_ValArray, _Tp>, _Tp>
+    valarray<_Tp>::apply(_Tp __func(_Tp)) const
+    {
+      typedef _ValFunClos<_ValArray, _Tp> _Closure;
+      return _Expr<_Closure, _Tp>(_Closure(*this, __func));
+    }
+
+  template<class _Tp>
+    inline _Expr<_RefFunClos<_ValArray, _Tp>, _Tp>
+    valarray<_Tp>::apply(_Tp __func(const _Tp &)) const
+    {
+      typedef _RefFunClos<_ValArray, _Tp> _Closure;
+      return _Expr<_Closure, _Tp>(_Closure(*this, __func));
+    }
+
+#define _DEFINE_VALARRAY_UNARY_OPERATOR(_Op, _Name)                     \
+  template<typename _Tp>						\
+    inline typename valarray<_Tp>::template _UnaryOp<_Name>::_Rt	\
+    valarray<_Tp>::operator _Op() const					\
+    {									\
+      typedef _UnClos<_Name, _ValArray, _Tp> _Closure;			\
+      typedef typename __fun<_Name, _Tp>::result_type _Rt;		\
+      return _Expr<_Closure, _Rt>(_Closure(*this));			\
+    }
+
+    _DEFINE_VALARRAY_UNARY_OPERATOR(+, __unary_plus)
+    _DEFINE_VALARRAY_UNARY_OPERATOR(-, __negate)
+    _DEFINE_VALARRAY_UNARY_OPERATOR(~, __bitwise_not)
+    _DEFINE_VALARRAY_UNARY_OPERATOR (!, __logical_not)
+
+#undef _DEFINE_VALARRAY_UNARY_OPERATOR
+
+#define _DEFINE_VALARRAY_AUGMENTED_ASSIGNMENT(_Op, _Name)               \
+  template<class _Tp>							\
+    inline valarray<_Tp>&						\
+    valarray<_Tp>::operator _Op##=(const _Tp &__t)			\
+    {									\
+      _Array_augmented_##_Name(_Array<_Tp>(_M_data), _M_size, __t);	\
+      return *this;							\
+    }									\
+									\
+  template<class _Tp>							\
+    inline valarray<_Tp>&						\
+    valarray<_Tp>::operator _Op##=(const valarray<_Tp> &__v)		\
+    {									\
+      __glibcxx_assert(_M_size == __v._M_size);				\
+      _Array_augmented_##_Name(_Array<_Tp>(_M_data), _M_size, 		\
+			       _Array<_Tp>(__v._M_data));		\
+      return *this;							\
+    }
+
+_DEFINE_VALARRAY_AUGMENTED_ASSIGNMENT(+, __plus)
+_DEFINE_VALARRAY_AUGMENTED_ASSIGNMENT(-, __minus)
+_DEFINE_VALARRAY_AUGMENTED_ASSIGNMENT(*, __multiplies)
+_DEFINE_VALARRAY_AUGMENTED_ASSIGNMENT(/, __divides)
+_DEFINE_VALARRAY_AUGMENTED_ASSIGNMENT(%, __modulus)
+_DEFINE_VALARRAY_AUGMENTED_ASSIGNMENT(^, __bitwise_xor)
+_DEFINE_VALARRAY_AUGMENTED_ASSIGNMENT(&, __bitwise_and)
+_DEFINE_VALARRAY_AUGMENTED_ASSIGNMENT(|, __bitwise_or)
+_DEFINE_VALARRAY_AUGMENTED_ASSIGNMENT(<<, __shift_left)
+_DEFINE_VALARRAY_AUGMENTED_ASSIGNMENT(>>, __shift_right)
+
+#undef _DEFINE_VALARRAY_AUGMENTED_ASSIGNMENT
+
+#define _DEFINE_VALARRAY_EXPR_AUGMENTED_ASSIGNMENT(_Op, _Name)          \
+  template<class _Tp> template<class _Dom>				\
+    inline valarray<_Tp>&						\
+    valarray<_Tp>::operator _Op##=(const _Expr<_Dom, _Tp>& __e)		\
+    {									\
+      _Array_augmented_##_Name(_Array<_Tp>(_M_data), __e, _M_size);	\
+      return *this;							\
+    }
+
+_DEFINE_VALARRAY_EXPR_AUGMENTED_ASSIGNMENT(+, __plus)
+_DEFINE_VALARRAY_EXPR_AUGMENTED_ASSIGNMENT(-, __minus)
+_DEFINE_VALARRAY_EXPR_AUGMENTED_ASSIGNMENT(*, __multiplies)
+_DEFINE_VALARRAY_EXPR_AUGMENTED_ASSIGNMENT(/, __divides)
+_DEFINE_VALARRAY_EXPR_AUGMENTED_ASSIGNMENT(%, __modulus)
+_DEFINE_VALARRAY_EXPR_AUGMENTED_ASSIGNMENT(^, __bitwise_xor)
+_DEFINE_VALARRAY_EXPR_AUGMENTED_ASSIGNMENT(&, __bitwise_and)
+_DEFINE_VALARRAY_EXPR_AUGMENTED_ASSIGNMENT(|, __bitwise_or)
+_DEFINE_VALARRAY_EXPR_AUGMENTED_ASSIGNMENT(<<, __shift_left)
+_DEFINE_VALARRAY_EXPR_AUGMENTED_ASSIGNMENT(>>, __shift_right)
+
+#undef _DEFINE_VALARRAY_EXPR_AUGMENTED_ASSIGNMENT
+
+
+#define _DEFINE_BINARY_OPERATOR(_Op, _Name)				\
+  template<typename _Tp>						\
+    inline _Expr<_BinClos<_Name, _ValArray, _ValArray, _Tp, _Tp>,	\
+		 typename __fun<_Name, _Tp>::result_type>		\
+    operator _Op(const valarray<_Tp>& __v, const valarray<_Tp>& __w)	\
+    {									\
+      __glibcxx_assert(__v.size() == __w.size());			\
+      typedef _BinClos<_Name, _ValArray, _ValArray, _Tp, _Tp> _Closure;	\
+      typedef typename __fun<_Name, _Tp>::result_type _Rt;		\
+      return _Expr<_Closure, _Rt>(_Closure(__v, __w));			\
+    }									\
+									\
+  template<typename _Tp>						\
+    inline _Expr<_BinClos<_Name, _ValArray,_Constant, _Tp, _Tp>,	\
+		 typename __fun<_Name, _Tp>::result_type>		\
+    operator _Op(const valarray<_Tp>& __v,				\
+		 const typename valarray<_Tp>::value_type& __t)		\
+    {									\
+      typedef _BinClos<_Name, _ValArray, _Constant, _Tp, _Tp> _Closure;	\
+      typedef typename __fun<_Name, _Tp>::result_type _Rt;		\
+      return _Expr<_Closure, _Rt>(_Closure(__v, __t));			\
+    }									\
+									\
+  template<typename _Tp>						\
+    inline _Expr<_BinClos<_Name, _Constant, _ValArray, _Tp, _Tp>,	\
+		 typename __fun<_Name, _Tp>::result_type>		\
+    operator _Op(const typename valarray<_Tp>::value_type& __t,		\
+		 const valarray<_Tp>& __v)				\
+    {									\
+      typedef _BinClos<_Name, _Constant, _ValArray, _Tp, _Tp> _Closure;	\
+      typedef typename __fun<_Name, _Tp>::result_type _Rt;		\
+      return _Expr<_Closure, _Rt>(_Closure(__t, __v));			\
+    }
+
+_DEFINE_BINARY_OPERATOR(+, __plus)
+_DEFINE_BINARY_OPERATOR(-, __minus)
+_DEFINE_BINARY_OPERATOR(*, __multiplies)
+_DEFINE_BINARY_OPERATOR(/, __divides)
+_DEFINE_BINARY_OPERATOR(%, __modulus)
+_DEFINE_BINARY_OPERATOR(^, __bitwise_xor)
+_DEFINE_BINARY_OPERATOR(&, __bitwise_and)
+_DEFINE_BINARY_OPERATOR(|, __bitwise_or)
+_DEFINE_BINARY_OPERATOR(<<, __shift_left)
+_DEFINE_BINARY_OPERATOR(>>, __shift_right)
+_DEFINE_BINARY_OPERATOR(&&, __logical_and)
+_DEFINE_BINARY_OPERATOR(||, __logical_or)
+_DEFINE_BINARY_OPERATOR(==, __equal_to)
+_DEFINE_BINARY_OPERATOR(!=, __not_equal_to)
+_DEFINE_BINARY_OPERATOR(<, __less)
+_DEFINE_BINARY_OPERATOR(>, __greater)
+_DEFINE_BINARY_OPERATOR(<=, __less_equal)
+_DEFINE_BINARY_OPERATOR(>=, __greater_equal)
+
+#undef _DEFINE_BINARY_OPERATOR
+
+#if __cplusplus >= 201103L
+  /**
+   *  @brief  Return an iterator pointing to the first element of
+   *          the valarray.
+   *  @param  __va  valarray.
+   */
+  template<class _Tp>
+    [[__nodiscard__]]
+    inline _Tp*
+    begin(valarray<_Tp>& __va) noexcept
+    { return __va.size() ? std::__addressof(__va[0]) : nullptr; }
+
+  /**
+   *  @brief  Return an iterator pointing to the first element of
+   *          the const valarray.
+   *  @param  __va  valarray.
+   */
+  template<class _Tp>
+    [[__nodiscard__]]
+    inline const _Tp*
+    begin(const valarray<_Tp>& __va) noexcept
+    { return __va.size() ? std::__addressof(__va[0]) : nullptr; }
+
+  /**
+   *  @brief  Return an iterator pointing to one past the last element of
+   *          the valarray.
+   *  @param  __va  valarray.
+   */
+  template<class _Tp>
+    [[__nodiscard__]]
+    inline _Tp*
+    end(valarray<_Tp>& __va) noexcept
+    {
+      if (auto __n = __va.size())
+	return std::__addressof(__va[0]) + __n;
+      else
+	return nullptr;
+    }
+
+  /**
+   *  @brief  Return an iterator pointing to one past the last element of
+   *          the const valarray.
+   *  @param  __va  valarray.
+   */
+  template<class _Tp>
+    [[__nodiscard__]]
+    inline const _Tp*
+    end(const valarray<_Tp>& __va) noexcept
+    {
+      if (auto __n = __va.size())
+	return std::__addressof(__va[0]) + __n;
+      else
+	return nullptr;
+    }
+#endif // C++11
+
+  /// @} group numeric_arrays
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif /* _GLIBCXX_VALARRAY */
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@@ -0,0 +1,149 @@
+// <vector> -*- C++ -*-
+
+// Copyright (C) 2001-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/*
+ *
+ * Copyright (c) 1994
+ * Hewlett-Packard Company
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Hewlett-Packard Company makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ *
+ *
+ * Copyright (c) 1996
+ * Silicon Graphics Computer Systems, Inc.
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Silicon Graphics makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ */
+
+/** @file include/vector
+ *  This is a Standard C++ Library header.
+ */
+
+#ifndef _GLIBCXX_VECTOR
+#define _GLIBCXX_VECTOR 1
+
+#pragma GCC system_header
+
+#include <bits/stl_algobase.h>
+#include <bits/allocator.h>
+#include <bits/stl_construct.h>
+#include <bits/stl_uninitialized.h>
+#include <bits/stl_vector.h>
+#include <bits/stl_bvector.h>
+#include <bits/refwrap.h>
+#include <bits/range_access.h>
+
+#ifndef _GLIBCXX_EXPORT_TEMPLATE
+# include <bits/vector.tcc>
+#endif
+
+#ifdef _GLIBCXX_DEBUG
+# include <debug/vector>
+#endif
+
+#if __cplusplus >= 201703L
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+  namespace pmr {
+    template<typename _Tp> class polymorphic_allocator;
+    template<typename _Tp>
+      using vector = std::vector<_Tp, polymorphic_allocator<_Tp>>;
+  } // namespace pmr
+# ifdef _GLIBCXX_DEBUG
+  namespace _GLIBCXX_STD_C::pmr {
+    template<typename _Tp>
+      using vector
+	= _GLIBCXX_STD_C::vector<_Tp, std::pmr::polymorphic_allocator<_Tp>>;
+  } // namespace _GLIBCXX_STD_C::pmr
+# endif
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+#endif // C++17
+
+#if __cplusplus > 201703L
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+#define __cpp_lib_erase_if 202002L
+
+  template<typename _Tp, typename _Alloc, typename _Predicate>
+    _GLIBCXX20_CONSTEXPR
+    inline typename vector<_Tp, _Alloc>::size_type
+    erase_if(vector<_Tp, _Alloc>& __cont, _Predicate __pred)
+    {
+      using namespace __gnu_cxx;
+      _GLIBCXX_STD_C::vector<_Tp, _Alloc>& __ucont = __cont;
+      const auto __osz = __cont.size();
+      const auto __end = __ucont.end();
+      auto __removed = std::__remove_if(__ucont.begin(), __end,
+					__ops::__pred_iter(std::ref(__pred)));
+      if (__removed != __end)
+	{
+	  __cont.erase(__niter_wrap(__cont.begin(), __removed),
+		       __cont.end());
+	  return __osz - __cont.size();
+	}
+
+      return 0;
+    }
+
+  template<typename _Tp, typename _Alloc, typename _Up>
+    _GLIBCXX20_CONSTEXPR
+    inline typename vector<_Tp, _Alloc>::size_type
+    erase(vector<_Tp, _Alloc>& __cont, const _Up& __value)
+    {
+      using namespace __gnu_cxx;
+      _GLIBCXX_STD_C::vector<_Tp, _Alloc>& __ucont = __cont;
+      const auto __osz = __cont.size();
+      const auto __end = __ucont.end();
+      auto __removed = std::__remove_if(__ucont.begin(), __end,
+					__ops::__iter_equals_val(__value));
+      if (__removed != __end)
+	{
+	  __cont.erase(__niter_wrap(__cont.begin(), __removed),
+		       __cont.end());
+	  return __osz - __cont.size();
+	}
+
+      return 0;
+    }
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+#endif // C++20
+
+#endif /* _GLIBCXX_VECTOR */
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@@ -0,0 +1,40 @@
+// Low-level type for atomic operations -*- C++ -*-
+
+// Copyright (C) 2004-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file atomic_word.h
+ *  This file is a GNU extension to the Standard C++ Library.
+ */
+
+#ifndef _GLIBCXX_ATOMIC_WORD_H
+#define _GLIBCXX_ATOMIC_WORD_H	1
+
+typedef int _Atomic_word;
+
+
+// This is a memory order acquire fence.
+#define _GLIBCXX_READ_MEM_BARRIER __atomic_thread_fence (__ATOMIC_ACQUIRE)
+// This is a memory order release fence.
+#define _GLIBCXX_WRITE_MEM_BARRIER __atomic_thread_fence (__ATOMIC_RELEASE)
+
+#endif
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@@ -0,0 +1,135 @@
+// Wrapper of C-language FILE struct -*- C++ -*-
+
+// Copyright (C) 2000-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+//
+// ISO C++ 14882: 27.8  File-based streams
+//
+
+/** @file bits/basic_file.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{ios}
+ */
+
+#ifndef _GLIBCXX_BASIC_FILE_STDIO_H
+#define _GLIBCXX_BASIC_FILE_STDIO_H 1
+
+#pragma GCC system_header
+
+#include <bits/c++config.h>
+#include <bits/c++io.h>  // for __c_lock and __c_file
+#include <bits/move.h>   // for swap
+#include <ios>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  // Generic declaration.
+  template<typename _CharT>
+    class __basic_file;
+
+  // Specialization.
+  template<>
+    class __basic_file<char>
+    {
+      // Underlying data source/sink.
+      __c_file* 	_M_cfile;
+
+      // True iff we opened _M_cfile, and thus must close it ourselves.
+      bool 		_M_cfile_created;
+
+    public:
+      __basic_file(__c_lock* __lock = 0) throw ();
+
+#if __cplusplus >= 201103L
+      __basic_file(__basic_file&& __rv, __c_lock* = 0) noexcept
+      : _M_cfile(__rv._M_cfile), _M_cfile_created(__rv._M_cfile_created)
+      {
+	__rv._M_cfile = nullptr;
+	__rv._M_cfile_created = false;
+      }
+
+      __basic_file& operator=(const __basic_file&) = delete;
+      __basic_file& operator=(__basic_file&&) = delete;
+
+      void
+      swap(__basic_file& __f) noexcept
+      {
+	std::swap(_M_cfile, __f._M_cfile);
+	std::swap(_M_cfile_created, __f._M_cfile_created);
+      }
+#endif
+
+      __basic_file*
+      open(const char* __name, ios_base::openmode __mode, int __prot = 0664);
+
+#if _GLIBCXX_HAVE__WFOPEN && _GLIBCXX_USE_WCHAR_T
+      __basic_file*
+      open(const wchar_t* __name, ios_base::openmode __mode);
+#endif
+
+      __basic_file*
+      sys_open(__c_file* __file, ios_base::openmode);
+
+      __basic_file*
+      sys_open(int __fd, ios_base::openmode __mode) throw ();
+
+      __basic_file*
+      close();
+
+      _GLIBCXX_PURE bool
+      is_open() const throw ();
+
+      _GLIBCXX_PURE int
+      fd() throw ();
+
+      _GLIBCXX_PURE __c_file*
+      file() throw ();
+
+      ~__basic_file();
+
+      streamsize
+      xsputn(const char* __s, streamsize __n);
+
+      streamsize
+      xsputn_2(const char* __s1, streamsize __n1,
+	       const char* __s2, streamsize __n2);
+
+      streamsize
+      xsgetn(char* __s, streamsize __n);
+
+      streamoff
+      seekoff(streamoff __off, ios_base::seekdir __way) throw ();
+
+      int
+      sync();
+
+      streamsize
+      showmanyc();
+    };
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif
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@@ -0,0 +1,64 @@
+// Base to std::allocator -*- C++ -*-
+
+// Copyright (C) 2004-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/c++allocator.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{memory}
+ */
+
+#ifndef _GLIBCXX_CXX_ALLOCATOR_H
+#define _GLIBCXX_CXX_ALLOCATOR_H 1
+
+#include <bits/new_allocator.h>
+
+#if __cplusplus >= 201103L
+namespace std
+{
+  /**
+   *  @brief  An alias to the base class for std::allocator.
+   *
+   *  Used to set the std::allocator base class to std::__new_allocator.
+   *
+   *  @ingroup allocators
+   *  @tparam  _Tp  Type of allocated object.
+    */
+  template<typename _Tp>
+    using __allocator_base = __new_allocator<_Tp>;
+}
+#else
+// Define __new_allocator as the base class to std::allocator.
+# define __allocator_base  __new_allocator
+#endif
+
+#ifndef _GLIBCXX_SANITIZE_STD_ALLOCATOR
+# if defined(__SANITIZE_ADDRESS__)
+#  define _GLIBCXX_SANITIZE_STD_ALLOCATOR 1
+# elif defined __has_feature
+#  if __has_feature(address_sanitizer)
+#   define _GLIBCXX_SANITIZE_STD_ALLOCATOR 1
+#  endif
+# endif
+#endif
+
+#endif
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@@ -0,0 +1,2235 @@
+// Predefined symbols and macros -*- C++ -*-
+
+// Copyright (C) 1997-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/c++config.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{version}
+ */
+
+#ifndef _GLIBCXX_CXX_CONFIG_H
+#define _GLIBCXX_CXX_CONFIG_H 1
+
+// The major release number for the GCC release the C++ library belongs to.
+#define _GLIBCXX_RELEASE 12
+
+// The datestamp of the C++ library in compressed ISO date format.
+#define __GLIBCXX__ 20220819
+
+// Macros for various attributes.
+//   _GLIBCXX_PURE
+//   _GLIBCXX_CONST
+//   _GLIBCXX_NORETURN
+//   _GLIBCXX_NOTHROW
+//   _GLIBCXX_VISIBILITY
+#ifndef _GLIBCXX_PURE
+# define _GLIBCXX_PURE __attribute__ ((__pure__))
+#endif
+
+#ifndef _GLIBCXX_CONST
+# define _GLIBCXX_CONST __attribute__ ((__const__))
+#endif
+
+#ifndef _GLIBCXX_NORETURN
+# define _GLIBCXX_NORETURN __attribute__ ((__noreturn__))
+#endif
+
+// See below for C++
+#ifndef _GLIBCXX_NOTHROW
+# ifndef __cplusplus
+#  define _GLIBCXX_NOTHROW __attribute__((__nothrow__))
+# endif
+#endif
+
+// Macros for visibility attributes.
+//   _GLIBCXX_HAVE_ATTRIBUTE_VISIBILITY
+//   _GLIBCXX_VISIBILITY
+# define _GLIBCXX_HAVE_ATTRIBUTE_VISIBILITY 1
+
+#if _GLIBCXX_HAVE_ATTRIBUTE_VISIBILITY
+# define _GLIBCXX_VISIBILITY(V) __attribute__ ((__visibility__ (#V)))
+#else
+// If this is not supplied by the OS-specific or CPU-specific
+// headers included below, it will be defined to an empty default.
+# define _GLIBCXX_VISIBILITY(V) _GLIBCXX_PSEUDO_VISIBILITY(V)
+#endif
+
+// Macros for deprecated attributes.
+//   _GLIBCXX_USE_DEPRECATED
+//   _GLIBCXX_DEPRECATED
+//   _GLIBCXX_DEPRECATED_SUGGEST( string-literal )
+//   _GLIBCXX11_DEPRECATED
+//   _GLIBCXX11_DEPRECATED_SUGGEST( string-literal )
+//   _GLIBCXX14_DEPRECATED
+//   _GLIBCXX14_DEPRECATED_SUGGEST( string-literal )
+//   _GLIBCXX17_DEPRECATED
+//   _GLIBCXX17_DEPRECATED_SUGGEST( string-literal )
+//   _GLIBCXX20_DEPRECATED( string-literal )
+//   _GLIBCXX20_DEPRECATED_SUGGEST( string-literal )
+#ifndef _GLIBCXX_USE_DEPRECATED
+# define _GLIBCXX_USE_DEPRECATED 1
+#endif
+
+#if defined(__DEPRECATED)
+# define _GLIBCXX_DEPRECATED __attribute__ ((__deprecated__))
+# define _GLIBCXX_DEPRECATED_SUGGEST(ALT) \
+  __attribute__ ((__deprecated__ ("use '" ALT "' instead")))
+#else
+# define _GLIBCXX_DEPRECATED
+# define _GLIBCXX_DEPRECATED_SUGGEST(ALT)
+#endif
+
+#if defined(__DEPRECATED) && (__cplusplus >= 201103L)
+# define _GLIBCXX11_DEPRECATED _GLIBCXX_DEPRECATED
+# define _GLIBCXX11_DEPRECATED_SUGGEST(ALT) _GLIBCXX_DEPRECATED_SUGGEST(ALT)
+#else
+# define _GLIBCXX11_DEPRECATED
+# define _GLIBCXX11_DEPRECATED_SUGGEST(ALT)
+#endif
+
+#if defined(__DEPRECATED) && (__cplusplus >= 201402L)
+# define _GLIBCXX14_DEPRECATED _GLIBCXX_DEPRECATED
+# define _GLIBCXX14_DEPRECATED_SUGGEST(ALT) _GLIBCXX_DEPRECATED_SUGGEST(ALT)
+#else
+# define _GLIBCXX14_DEPRECATED
+# define _GLIBCXX14_DEPRECATED_SUGGEST(ALT)
+#endif
+
+#if defined(__DEPRECATED) && (__cplusplus >= 201703L)
+# define _GLIBCXX17_DEPRECATED [[__deprecated__]]
+# define _GLIBCXX17_DEPRECATED_SUGGEST(ALT) _GLIBCXX_DEPRECATED_SUGGEST(ALT)
+#else
+# define _GLIBCXX17_DEPRECATED
+# define _GLIBCXX17_DEPRECATED_SUGGEST(ALT)
+#endif
+
+#if defined(__DEPRECATED) && (__cplusplus >= 202002L)
+# define _GLIBCXX20_DEPRECATED(MSG) [[deprecated(MSG)]]
+# define _GLIBCXX20_DEPRECATED_SUGGEST(ALT) _GLIBCXX_DEPRECATED_SUGGEST(ALT)
+#else
+# define _GLIBCXX20_DEPRECATED(MSG)
+# define _GLIBCXX20_DEPRECATED_SUGGEST(ALT)
+#endif
+
+// Macros for ABI tag attributes.
+#ifndef _GLIBCXX_ABI_TAG_CXX11
+# define _GLIBCXX_ABI_TAG_CXX11 __attribute ((__abi_tag__ ("cxx11")))
+#endif
+
+// Macro to warn about unused results.
+#if __cplusplus >= 201703L
+# define _GLIBCXX_NODISCARD [[__nodiscard__]]
+#else
+# define _GLIBCXX_NODISCARD
+#endif
+
+
+
+#if __cplusplus
+
+// Macro for constexpr, to support in mixed 03/0x mode.
+#ifndef _GLIBCXX_CONSTEXPR
+# if __cplusplus >= 201103L
+#  define _GLIBCXX_CONSTEXPR constexpr
+#  define _GLIBCXX_USE_CONSTEXPR constexpr
+# else
+#  define _GLIBCXX_CONSTEXPR
+#  define _GLIBCXX_USE_CONSTEXPR const
+# endif
+#endif
+
+#ifndef _GLIBCXX14_CONSTEXPR
+# if __cplusplus >= 201402L
+#  define _GLIBCXX14_CONSTEXPR constexpr
+# else
+#  define _GLIBCXX14_CONSTEXPR
+# endif
+#endif
+
+#ifndef _GLIBCXX17_CONSTEXPR
+# if __cplusplus >= 201703L
+#  define _GLIBCXX17_CONSTEXPR constexpr
+# else
+#  define _GLIBCXX17_CONSTEXPR
+# endif
+#endif
+
+#ifndef _GLIBCXX20_CONSTEXPR
+# if __cplusplus >= 202002L
+#  define _GLIBCXX20_CONSTEXPR constexpr
+# else
+#  define _GLIBCXX20_CONSTEXPR
+# endif
+#endif
+
+#ifndef _GLIBCXX23_CONSTEXPR
+# if __cplusplus >= 202100L
+#  define _GLIBCXX23_CONSTEXPR constexpr
+# else
+#  define _GLIBCXX23_CONSTEXPR
+# endif
+#endif
+
+#ifndef _GLIBCXX17_INLINE
+# if __cplusplus >= 201703L
+#  define _GLIBCXX17_INLINE inline
+# else
+#  define _GLIBCXX17_INLINE
+# endif
+#endif
+
+// Macro for noexcept, to support in mixed 03/0x mode.
+#ifndef _GLIBCXX_NOEXCEPT
+# if __cplusplus >= 201103L
+#  define _GLIBCXX_NOEXCEPT noexcept
+#  define _GLIBCXX_NOEXCEPT_IF(...) noexcept(__VA_ARGS__)
+#  define _GLIBCXX_USE_NOEXCEPT noexcept
+#  define _GLIBCXX_THROW(_EXC)
+# else
+#  define _GLIBCXX_NOEXCEPT
+#  define _GLIBCXX_NOEXCEPT_IF(...)
+#  define _GLIBCXX_USE_NOEXCEPT throw()
+#  define _GLIBCXX_THROW(_EXC) throw(_EXC)
+# endif
+#endif
+
+#ifndef _GLIBCXX_NOTHROW
+# define _GLIBCXX_NOTHROW _GLIBCXX_USE_NOEXCEPT
+#endif
+
+#ifndef _GLIBCXX_THROW_OR_ABORT
+# if __cpp_exceptions
+#  define _GLIBCXX_THROW_OR_ABORT(_EXC) (throw (_EXC))
+# else
+#  define _GLIBCXX_THROW_OR_ABORT(_EXC) (__builtin_abort())
+# endif
+#endif
+
+#if __cpp_noexcept_function_type
+#define _GLIBCXX_NOEXCEPT_PARM , bool _NE
+#define _GLIBCXX_NOEXCEPT_QUAL noexcept (_NE)
+#else
+#define _GLIBCXX_NOEXCEPT_PARM
+#define _GLIBCXX_NOEXCEPT_QUAL
+#endif
+
+// Macro for extern template, ie controlling template linkage via use
+// of extern keyword on template declaration. As documented in the g++
+// manual, it inhibits all implicit instantiations and is used
+// throughout the library to avoid multiple weak definitions for
+// required types that are already explicitly instantiated in the
+// library binary. This substantially reduces the binary size of
+// resulting executables.
+// Special case: _GLIBCXX_EXTERN_TEMPLATE == -1 disallows extern
+// templates only in basic_string, thus activating its debug-mode
+// checks even at -O0.
+# define _GLIBCXX_EXTERN_TEMPLATE 1
+
+/*
+  Outline of libstdc++ namespaces.
+
+  namespace std
+  {
+    namespace __debug { }
+    namespace __parallel { }
+    namespace __cxx1998 { }
+
+    namespace __detail {
+      namespace __variant { }				// C++17
+    }
+
+    namespace rel_ops { }
+
+    namespace tr1
+    {
+      namespace placeholders { }
+      namespace regex_constants { }
+      namespace __detail { }
+    }
+
+    namespace tr2 { }
+    
+    namespace decimal { }
+
+    namespace chrono { }				// C++11
+    namespace placeholders { }				// C++11
+    namespace regex_constants { }			// C++11
+    namespace this_thread { }				// C++11
+    inline namespace literals {				// C++14
+      inline namespace chrono_literals { }		// C++14
+      inline namespace complex_literals { }		// C++14
+      inline namespace string_literals { }		// C++14
+      inline namespace string_view_literals { }		// C++17
+    }
+  }
+
+  namespace abi { }
+
+  namespace __gnu_cxx
+  {
+    namespace __detail { }
+  }
+
+  For full details see:
+  http://gcc.gnu.org/onlinedocs/libstdc++/latest-doxygen/namespaces.html
+*/
+namespace std
+{
+  typedef __SIZE_TYPE__ 	size_t;
+  typedef __PTRDIFF_TYPE__	ptrdiff_t;
+
+#if __cplusplus >= 201103L
+  typedef decltype(nullptr)	nullptr_t;
+#endif
+
+#pragma GCC visibility push(default)
+  // This allows the library to terminate without including all of <exception>
+  // and without making the declaration of std::terminate visible to users.
+  extern "C++" __attribute__ ((__noreturn__, __always_inline__))
+  inline void __terminate() _GLIBCXX_USE_NOEXCEPT
+  {
+    void terminate() _GLIBCXX_USE_NOEXCEPT __attribute__ ((__noreturn__));
+    terminate();
+  }
+#pragma GCC visibility pop
+}
+
+# define _GLIBCXX_USE_DUAL_ABI 1
+
+#if ! _GLIBCXX_USE_DUAL_ABI
+// Ignore any pre-defined value of _GLIBCXX_USE_CXX11_ABI
+# undef _GLIBCXX_USE_CXX11_ABI
+#endif
+
+#ifndef _GLIBCXX_USE_CXX11_ABI
+# define _GLIBCXX_USE_CXX11_ABI 1
+#endif
+
+#if _GLIBCXX_USE_CXX11_ABI
+namespace std
+{
+  inline namespace __cxx11 __attribute__((__abi_tag__ ("cxx11"))) { }
+}
+namespace __gnu_cxx
+{
+  inline namespace __cxx11 __attribute__((__abi_tag__ ("cxx11"))) { }
+}
+# define _GLIBCXX_NAMESPACE_CXX11 __cxx11::
+# define _GLIBCXX_BEGIN_NAMESPACE_CXX11 namespace __cxx11 {
+# define _GLIBCXX_END_NAMESPACE_CXX11 }
+# define _GLIBCXX_DEFAULT_ABI_TAG _GLIBCXX_ABI_TAG_CXX11
+#else
+# define _GLIBCXX_NAMESPACE_CXX11
+# define _GLIBCXX_BEGIN_NAMESPACE_CXX11
+# define _GLIBCXX_END_NAMESPACE_CXX11
+# define _GLIBCXX_DEFAULT_ABI_TAG
+#endif
+
+// Defined if inline namespaces are used for versioning.
+# define _GLIBCXX_INLINE_VERSION 0 
+
+// Inline namespace for symbol versioning.
+#if _GLIBCXX_INLINE_VERSION
+# define _GLIBCXX_BEGIN_NAMESPACE_VERSION namespace __8 {
+# define _GLIBCXX_END_NAMESPACE_VERSION }
+
+namespace std
+{
+inline _GLIBCXX_BEGIN_NAMESPACE_VERSION
+#if __cplusplus >= 201402L
+  inline namespace literals {
+    inline namespace chrono_literals { }
+    inline namespace complex_literals { }
+    inline namespace string_literals { }
+#if __cplusplus > 201402L
+    inline namespace string_view_literals { }
+#endif // C++17
+  }
+#endif // C++14
+_GLIBCXX_END_NAMESPACE_VERSION
+}
+
+namespace __gnu_cxx
+{
+inline _GLIBCXX_BEGIN_NAMESPACE_VERSION
+_GLIBCXX_END_NAMESPACE_VERSION
+}
+
+#else
+# define _GLIBCXX_BEGIN_NAMESPACE_VERSION
+# define _GLIBCXX_END_NAMESPACE_VERSION
+#endif
+
+// Inline namespaces for special modes: debug, parallel.
+#if defined(_GLIBCXX_DEBUG) || defined(_GLIBCXX_PARALLEL)
+namespace std
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  // Non-inline namespace for components replaced by alternates in active mode.
+  namespace __cxx1998
+  {
+# if _GLIBCXX_USE_CXX11_ABI
+  inline namespace __cxx11 __attribute__((__abi_tag__ ("cxx11"))) { }
+# endif
+  }
+
+_GLIBCXX_END_NAMESPACE_VERSION
+
+  // Inline namespace for debug mode.
+# ifdef _GLIBCXX_DEBUG
+  inline namespace __debug { }
+# endif
+
+  // Inline namespaces for parallel mode.
+# ifdef _GLIBCXX_PARALLEL
+  inline namespace __parallel { }
+# endif
+}
+
+// Check for invalid usage and unsupported mixed-mode use.
+# if defined(_GLIBCXX_DEBUG) && defined(_GLIBCXX_PARALLEL)
+#  error illegal use of multiple inlined namespaces
+# endif
+
+// Check for invalid use due to lack for weak symbols.
+# if __NO_INLINE__ && !__GXX_WEAK__
+#  warning currently using inlined namespace mode which may fail \
+   without inlining due to lack of weak symbols
+# endif
+#endif
+
+// Macros for namespace scope. Either namespace std:: or the name
+// of some nested namespace within it corresponding to the active mode.
+// _GLIBCXX_STD_A
+// _GLIBCXX_STD_C
+//
+// Macros for opening/closing conditional namespaces.
+// _GLIBCXX_BEGIN_NAMESPACE_ALGO
+// _GLIBCXX_END_NAMESPACE_ALGO
+// _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
+// _GLIBCXX_END_NAMESPACE_CONTAINER
+#if defined(_GLIBCXX_DEBUG)
+# define _GLIBCXX_STD_C __cxx1998
+# define _GLIBCXX_BEGIN_NAMESPACE_CONTAINER \
+	 namespace _GLIBCXX_STD_C {
+# define _GLIBCXX_END_NAMESPACE_CONTAINER }
+#else
+# define _GLIBCXX_STD_C std
+# define _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
+# define _GLIBCXX_END_NAMESPACE_CONTAINER
+#endif
+
+#ifdef _GLIBCXX_PARALLEL
+# define _GLIBCXX_STD_A __cxx1998
+# define _GLIBCXX_BEGIN_NAMESPACE_ALGO \
+	 namespace _GLIBCXX_STD_A {
+# define _GLIBCXX_END_NAMESPACE_ALGO }
+#else
+# define _GLIBCXX_STD_A std
+# define _GLIBCXX_BEGIN_NAMESPACE_ALGO
+# define _GLIBCXX_END_NAMESPACE_ALGO
+#endif
+
+// GLIBCXX_ABI Deprecated
+// Define if compatibility should be provided for -mlong-double-64.
+#undef _GLIBCXX_LONG_DOUBLE_COMPAT
+
+// Define if compatibility should be provided for alternative 128-bit long
+// double formats. Not possible for Clang until __ibm128 is supported.
+#ifndef __clang__
+#undef _GLIBCXX_LONG_DOUBLE_ALT128_COMPAT
+#endif
+
+// Inline namespaces for long double 128 modes.
+#if defined _GLIBCXX_LONG_DOUBLE_ALT128_COMPAT \
+  && defined __LONG_DOUBLE_IEEE128__
+namespace std
+{
+  // Namespaces for 128-bit IEEE long double format on 64-bit POWER LE.
+  inline namespace __gnu_cxx_ieee128 { }
+  inline namespace __gnu_cxx11_ieee128 { }
+}
+# define _GLIBCXX_NAMESPACE_LDBL __gnu_cxx_ieee128::
+# define _GLIBCXX_BEGIN_NAMESPACE_LDBL namespace __gnu_cxx_ieee128 {
+# define _GLIBCXX_END_NAMESPACE_LDBL }
+# define _GLIBCXX_NAMESPACE_LDBL_OR_CXX11 __gnu_cxx11_ieee128::
+# define _GLIBCXX_BEGIN_NAMESPACE_LDBL_OR_CXX11 namespace __gnu_cxx11_ieee128 {
+# define _GLIBCXX_END_NAMESPACE_LDBL_OR_CXX11 }
+
+#else // _GLIBCXX_LONG_DOUBLE_ALT128_COMPAT && IEEE128
+
+#if defined _GLIBCXX_LONG_DOUBLE_COMPAT && defined __LONG_DOUBLE_128__
+namespace std
+{
+  inline namespace __gnu_cxx_ldbl128 { }
+}
+# define _GLIBCXX_NAMESPACE_LDBL __gnu_cxx_ldbl128::
+# define _GLIBCXX_BEGIN_NAMESPACE_LDBL namespace __gnu_cxx_ldbl128 {
+# define _GLIBCXX_END_NAMESPACE_LDBL }
+#else
+# define _GLIBCXX_NAMESPACE_LDBL
+# define _GLIBCXX_BEGIN_NAMESPACE_LDBL
+# define _GLIBCXX_END_NAMESPACE_LDBL
+#endif
+
+#if _GLIBCXX_USE_CXX11_ABI
+# define _GLIBCXX_NAMESPACE_LDBL_OR_CXX11 _GLIBCXX_NAMESPACE_CXX11
+# define _GLIBCXX_BEGIN_NAMESPACE_LDBL_OR_CXX11 _GLIBCXX_BEGIN_NAMESPACE_CXX11
+# define _GLIBCXX_END_NAMESPACE_LDBL_OR_CXX11 _GLIBCXX_END_NAMESPACE_CXX11
+#else
+# define _GLIBCXX_NAMESPACE_LDBL_OR_CXX11 _GLIBCXX_NAMESPACE_LDBL
+# define _GLIBCXX_BEGIN_NAMESPACE_LDBL_OR_CXX11 _GLIBCXX_BEGIN_NAMESPACE_LDBL
+# define _GLIBCXX_END_NAMESPACE_LDBL_OR_CXX11 _GLIBCXX_END_NAMESPACE_LDBL
+#endif
+
+#endif // _GLIBCXX_LONG_DOUBLE_ALT128_COMPAT && IEEE128
+
+namespace std
+{
+#pragma GCC visibility push(default)
+  // Internal version of std::is_constant_evaluated().
+  // This can be used without checking if the compiler supports the feature.
+  // The macro _GLIBCXX_HAVE_IS_CONSTANT_EVALUATED can be used to check if
+  // the compiler support is present to make this function work as expected.
+  _GLIBCXX_CONSTEXPR inline bool
+  __is_constant_evaluated() _GLIBCXX_NOEXCEPT
+  {
+#if __cpp_if_consteval >= 202106L
+# define _GLIBCXX_HAVE_IS_CONSTANT_EVALUATED 1
+    if consteval { return true; } else { return false; }
+#elif __cplusplus >= 201103L && __has_builtin(__builtin_is_constant_evaluated)
+# define _GLIBCXX_HAVE_IS_CONSTANT_EVALUATED 1
+    return __builtin_is_constant_evaluated();
+#else
+    return false;
+#endif
+  }
+#pragma GCC visibility pop
+}
+
+// Debug Mode implies checking assertions.
+#if defined(_GLIBCXX_DEBUG) && !defined(_GLIBCXX_ASSERTIONS)
+# define _GLIBCXX_ASSERTIONS 1
+#endif
+
+// Disable std::string explicit instantiation declarations in order to assert.
+#ifdef _GLIBCXX_ASSERTIONS
+# undef _GLIBCXX_EXTERN_TEMPLATE
+# define _GLIBCXX_EXTERN_TEMPLATE -1
+#endif
+
+
+#if _GLIBCXX_HAVE_IS_CONSTANT_EVALUATED
+# define __glibcxx_constexpr_assert(cond) \
+  if (std::__is_constant_evaluated() && !bool(cond))	\
+    __builtin_unreachable() /* precondition violation detected! */
+#else
+# define __glibcxx_constexpr_assert(unevaluated)
+#endif
+
+#define _GLIBCXX_VERBOSE_ASSERT 1
+
+// Assert.
+#if defined(_GLIBCXX_ASSERTIONS) \
+  || defined(_GLIBCXX_PARALLEL) || defined(_GLIBCXX_PARALLEL_ASSERTIONS)
+# ifdef _GLIBCXX_VERBOSE_ASSERT
+namespace std
+{
+#pragma GCC visibility push(default)
+  // Avoid the use of assert, because we're trying to keep the <cassert>
+  // include out of the mix.
+  extern "C++" _GLIBCXX_NORETURN
+  void
+  __glibcxx_assert_fail(const char* __file, int __line,
+			const char* __function, const char* __condition)
+  _GLIBCXX_NOEXCEPT;
+#pragma GCC visibility pop
+}
+#define __glibcxx_assert_impl(_Condition)				\
+  if (__builtin_expect(!bool(_Condition), false))			\
+  {									\
+    __glibcxx_constexpr_assert(false);					\
+    std::__glibcxx_assert_fail(__FILE__, __LINE__, __PRETTY_FUNCTION__,	\
+			       #_Condition);				\
+  }
+# else // ! VERBOSE_ASSERT
+# define __glibcxx_assert_impl(_Condition)		\
+  if (__builtin_expect(!bool(_Condition), false))	\
+  {							\
+    __glibcxx_constexpr_assert(false);			\
+    __builtin_abort();					\
+  }
+# endif
+#endif
+
+#if defined(_GLIBCXX_ASSERTIONS)
+# define __glibcxx_assert(cond) \
+  do { __glibcxx_assert_impl(cond); } while (false)
+#else
+# define __glibcxx_assert(cond) \
+  do { __glibcxx_constexpr_assert(cond); } while (false)
+#endif
+
+// Macro indicating that TSAN is in use.
+#if __SANITIZE_THREAD__
+#  define _GLIBCXX_TSAN 1
+#elif defined __has_feature
+# if __has_feature(thread_sanitizer)
+#  define _GLIBCXX_TSAN 1
+# endif
+#endif
+
+// Macros for race detectors.
+// _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(A) and
+// _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(A) should be used to explain
+// atomic (lock-free) synchronization to race detectors:
+// the race detector will infer a happens-before arc from the former to the
+// latter when they share the same argument pointer.
+//
+// The most frequent use case for these macros (and the only case in the
+// current implementation of the library) is atomic reference counting:
+//   void _M_remove_reference()
+//   {
+//     _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&this->_M_refcount);
+//     if (__gnu_cxx::__exchange_and_add_dispatch(&this->_M_refcount, -1) <= 0)
+//       {
+//         _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&this->_M_refcount);
+//         _M_destroy(__a);
+//       }
+//   }
+// The annotations in this example tell the race detector that all memory
+// accesses occurred when the refcount was positive do not race with
+// memory accesses which occurred after the refcount became zero.
+#ifndef _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE
+# define  _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(A)
+#endif
+#ifndef _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER
+# define  _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(A)
+#endif
+
+// Macros for C linkage: define extern "C" linkage only when using C++.
+# define _GLIBCXX_BEGIN_EXTERN_C extern "C" {
+# define _GLIBCXX_END_EXTERN_C }
+
+# define _GLIBCXX_USE_ALLOCATOR_NEW 1
+
+#ifdef __SIZEOF_INT128__
+#if ! defined __GLIBCXX_TYPE_INT_N_0 && ! defined __STRICT_ANSI__
+// If __int128 is supported, we expect __GLIBCXX_TYPE_INT_N_0 to be defined
+// unless the compiler is in strict mode. If it's not defined and the strict
+// macro is not defined, something is wrong.
+#warning "__STRICT_ANSI__ seems to have been undefined; this is not supported"
+#endif
+#endif
+
+#else // !__cplusplus
+# define _GLIBCXX_BEGIN_EXTERN_C
+# define _GLIBCXX_END_EXTERN_C
+#endif
+
+
+// First includes.
+
+// Pick up any OS-specific definitions.
+#include <bits/os_defines.h>
+
+// Pick up any CPU-specific definitions.
+#include <bits/cpu_defines.h>
+
+// If platform uses neither visibility nor psuedo-visibility,
+// specify empty default for namespace annotation macros.
+#ifndef _GLIBCXX_PSEUDO_VISIBILITY
+# define _GLIBCXX_PSEUDO_VISIBILITY(V)
+#endif
+
+// Certain function definitions that are meant to be overridable from
+// user code are decorated with this macro.  For some targets, this
+// macro causes these definitions to be weak.
+#ifndef _GLIBCXX_WEAK_DEFINITION
+# define _GLIBCXX_WEAK_DEFINITION
+#endif
+
+// By default, we assume that __GXX_WEAK__ also means that there is support
+// for declaring functions as weak while not defining such functions.  This
+// allows for referring to functions provided by other libraries (e.g.,
+// libitm) without depending on them if the respective features are not used.
+#ifndef _GLIBCXX_USE_WEAK_REF
+# define _GLIBCXX_USE_WEAK_REF __GXX_WEAK__
+#endif
+
+// Conditionally enable annotations for the Transactional Memory TS on C++11.
+// Most of the following conditions are due to limitations in the current
+// implementation.
+#if __cplusplus >= 201103L && _GLIBCXX_USE_CXX11_ABI			\
+  && _GLIBCXX_USE_DUAL_ABI && __cpp_transactional_memory >= 201500L	\
+  &&  !_GLIBCXX_FULLY_DYNAMIC_STRING && _GLIBCXX_USE_WEAK_REF		\
+  && _GLIBCXX_USE_ALLOCATOR_NEW
+#define _GLIBCXX_TXN_SAFE transaction_safe
+#define _GLIBCXX_TXN_SAFE_DYN transaction_safe_dynamic
+#else
+#define _GLIBCXX_TXN_SAFE
+#define _GLIBCXX_TXN_SAFE_DYN
+#endif
+
+#if __cplusplus > 201402L
+// In C++17 mathematical special functions are in namespace std.
+# define _GLIBCXX_USE_STD_SPEC_FUNCS 1
+#elif __cplusplus >= 201103L && __STDCPP_WANT_MATH_SPEC_FUNCS__ != 0
+// For C++11 and C++14 they are in namespace std when requested.
+# define _GLIBCXX_USE_STD_SPEC_FUNCS 1
+#endif
+
+// The remainder of the prewritten config is automatic; all the
+// user hooks are listed above.
+
+// Create a boolean flag to be used to determine if --fast-math is set.
+#ifdef __FAST_MATH__
+# define _GLIBCXX_FAST_MATH 1
+#else
+# define _GLIBCXX_FAST_MATH 0
+#endif
+
+// This marks string literals in header files to be extracted for eventual
+// translation.  It is primarily used for messages in thrown exceptions; see
+// src/functexcept.cc.  We use __N because the more traditional _N is used
+// for something else under certain OSes (see BADNAMES).
+#define __N(msgid)     (msgid)
+
+// For example, <windows.h> is known to #define min and max as macros...
+#undef min
+#undef max
+
+// N.B. these _GLIBCXX_USE_C99_XXX macros are defined unconditionally
+// so they should be tested with #if not with #ifdef.
+#if __cplusplus >= 201103L
+# ifndef _GLIBCXX_USE_C99_MATH
+#  define _GLIBCXX_USE_C99_MATH _GLIBCXX11_USE_C99_MATH
+# endif
+# ifndef _GLIBCXX_USE_C99_COMPLEX
+# define _GLIBCXX_USE_C99_COMPLEX _GLIBCXX11_USE_C99_COMPLEX
+# endif
+# ifndef _GLIBCXX_USE_C99_STDIO
+# define _GLIBCXX_USE_C99_STDIO _GLIBCXX11_USE_C99_STDIO
+# endif
+# ifndef _GLIBCXX_USE_C99_STDLIB
+# define _GLIBCXX_USE_C99_STDLIB _GLIBCXX11_USE_C99_STDLIB
+# endif
+# ifndef _GLIBCXX_USE_C99_WCHAR
+# define _GLIBCXX_USE_C99_WCHAR _GLIBCXX11_USE_C99_WCHAR
+# endif
+#else
+# ifndef _GLIBCXX_USE_C99_MATH
+#  define _GLIBCXX_USE_C99_MATH _GLIBCXX98_USE_C99_MATH
+# endif
+# ifndef _GLIBCXX_USE_C99_COMPLEX
+# define _GLIBCXX_USE_C99_COMPLEX _GLIBCXX98_USE_C99_COMPLEX
+# endif
+# ifndef _GLIBCXX_USE_C99_STDIO
+# define _GLIBCXX_USE_C99_STDIO _GLIBCXX98_USE_C99_STDIO
+# endif
+# ifndef _GLIBCXX_USE_C99_STDLIB
+# define _GLIBCXX_USE_C99_STDLIB _GLIBCXX98_USE_C99_STDLIB
+# endif
+# ifndef _GLIBCXX_USE_C99_WCHAR
+# define _GLIBCXX_USE_C99_WCHAR _GLIBCXX98_USE_C99_WCHAR
+# endif
+#endif
+
+// Unless explicitly specified, enable char8_t extensions only if the core
+// language char8_t feature macro is defined.
+#ifndef _GLIBCXX_USE_CHAR8_T
+# ifdef __cpp_char8_t
+#  define _GLIBCXX_USE_CHAR8_T 1
+# endif
+#endif
+#ifdef _GLIBCXX_USE_CHAR8_T
+# define __cpp_lib_char8_t 201907L
+#endif
+
+/* Define if __float128 is supported on this host.  */
+#if defined(__FLOAT128__) || defined(__SIZEOF_FLOAT128__)
+/* For powerpc64 don't use __float128 when it's the same type as long double. */
+# if !(defined(_GLIBCXX_LONG_DOUBLE_ALT128_COMPAT) && defined(__LONG_DOUBLE_IEEE128__))
+#  define _GLIBCXX_USE_FLOAT128 1
+# endif
+#endif
+
+// Define if float has the IEEE binary32 format.
+#if __FLT_MANT_DIG__ == 24 \
+  && __FLT_MIN_EXP__ == -125 \
+  && __FLT_MAX_EXP__ == 128
+# define _GLIBCXX_FLOAT_IS_IEEE_BINARY32 1
+#endif
+
+// Define if double has the IEEE binary64 format.
+#if __DBL_MANT_DIG__ == 53 \
+  && __DBL_MIN_EXP__ == -1021 \
+  && __DBL_MAX_EXP__ == 1024
+# define _GLIBCXX_DOUBLE_IS_IEEE_BINARY64 1
+#endif
+
+#ifdef __has_builtin
+# ifdef __is_identifier
+// Intel and older Clang require !__is_identifier for some built-ins:
+#  define _GLIBCXX_HAS_BUILTIN(B) __has_builtin(B) || ! __is_identifier(B)
+# else
+#  define _GLIBCXX_HAS_BUILTIN(B) __has_builtin(B)
+# endif
+#endif
+
+#if _GLIBCXX_HAS_BUILTIN(__has_unique_object_representations)
+# define _GLIBCXX_HAVE_BUILTIN_HAS_UNIQ_OBJ_REP 1
+#endif
+
+#if _GLIBCXX_HAS_BUILTIN(__is_aggregate)
+# define _GLIBCXX_HAVE_BUILTIN_IS_AGGREGATE 1
+#endif
+
+#if _GLIBCXX_HAS_BUILTIN(__is_same)
+#  define _GLIBCXX_HAVE_BUILTIN_IS_SAME 1
+#endif
+
+#if _GLIBCXX_HAS_BUILTIN(__builtin_launder)
+# define _GLIBCXX_HAVE_BUILTIN_LAUNDER 1
+#endif
+
+#undef _GLIBCXX_HAS_BUILTIN
+
+// PSTL configuration
+
+#if __cplusplus >= 201703L
+// This header is not installed for freestanding:
+#if __has_include(<pstl/pstl_config.h>)
+// Preserved here so we have some idea which version of upstream we've pulled in
+// #define PSTL_VERSION 9000
+
+// For now this defaults to being based on the presence of Thread Building Blocks
+# ifndef _GLIBCXX_USE_TBB_PAR_BACKEND
+#  define _GLIBCXX_USE_TBB_PAR_BACKEND __has_include(<tbb/tbb.h>)
+# endif
+// This section will need some rework when a new (default) backend type is added
+# if _GLIBCXX_USE_TBB_PAR_BACKEND
+#  define _PSTL_PAR_BACKEND_TBB
+# else
+#  define _PSTL_PAR_BACKEND_SERIAL
+# endif
+
+# define _PSTL_ASSERT(_Condition) __glibcxx_assert(_Condition)
+# define _PSTL_ASSERT_MSG(_Condition, _Message) __glibcxx_assert(_Condition)
+
+#include <pstl/pstl_config.h>
+#endif // __has_include
+#endif // C++17
+
+// End of prewritten config; the settings discovered at configure time follow.
+/* config.h.  Generated from config.h.in by configure.  */
+/* config.h.in.  Generated from configure.ac by autoheader.  */
+
+/* Define to 1 if you have the `acosf' function. */
+#define _GLIBCXX_HAVE_ACOSF 1
+
+/* Define to 1 if you have the `acosl' function. */
+#define _GLIBCXX_HAVE_ACOSL 1
+
+/* Define to 1 if you have the `aligned_alloc' function. */
+#define _GLIBCXX_HAVE_ALIGNED_ALLOC 1
+
+/* Define if arc4random is available in <stdlib.h>. */
+/* #undef _GLIBCXX_HAVE_ARC4RANDOM */
+
+/* Define to 1 if you have the <arpa/inet.h> header file. */
+#define _GLIBCXX_HAVE_ARPA_INET_H 1
+
+/* Define to 1 if you have the `asinf' function. */
+#define _GLIBCXX_HAVE_ASINF 1
+
+/* Define to 1 if you have the `asinl' function. */
+#define _GLIBCXX_HAVE_ASINL 1
+
+/* Define to 1 if the target assembler supports .symver directive. */
+#define _GLIBCXX_HAVE_AS_SYMVER_DIRECTIVE 1
+
+/* Define to 1 if you have the `atan2f' function. */
+#define _GLIBCXX_HAVE_ATAN2F 1
+
+/* Define to 1 if you have the `atan2l' function. */
+#define _GLIBCXX_HAVE_ATAN2L 1
+
+/* Define to 1 if you have the `atanf' function. */
+#define _GLIBCXX_HAVE_ATANF 1
+
+/* Define to 1 if you have the `atanl' function. */
+#define _GLIBCXX_HAVE_ATANL 1
+
+/* Defined if shared_ptr reference counting should use atomic operations. */
+#define _GLIBCXX_HAVE_ATOMIC_LOCK_POLICY 1
+
+/* Define to 1 if you have the `at_quick_exit' function. */
+#define _GLIBCXX_HAVE_AT_QUICK_EXIT 1
+
+/* Define to 1 if the target assembler supports thread-local storage. */
+/* #undef _GLIBCXX_HAVE_CC_TLS */
+
+/* Define to 1 if you have the `ceilf' function. */
+#define _GLIBCXX_HAVE_CEILF 1
+
+/* Define to 1 if you have the `ceill' function. */
+#define _GLIBCXX_HAVE_CEILL 1
+
+/* Define to 1 if you have the <complex.h> header file. */
+#define _GLIBCXX_HAVE_COMPLEX_H 1
+
+/* Define to 1 if you have the `cosf' function. */
+#define _GLIBCXX_HAVE_COSF 1
+
+/* Define to 1 if you have the `coshf' function. */
+#define _GLIBCXX_HAVE_COSHF 1
+
+/* Define to 1 if you have the `coshl' function. */
+#define _GLIBCXX_HAVE_COSHL 1
+
+/* Define to 1 if you have the `cosl' function. */
+#define _GLIBCXX_HAVE_COSL 1
+
+/* Define to 1 if you have the declaration of `strnlen', and to 0 if you
+   don't. */
+#define _GLIBCXX_HAVE_DECL_STRNLEN 1
+
+/* Define to 1 if you have the <dirent.h> header file. */
+#define _GLIBCXX_HAVE_DIRENT_H 1
+
+/* Define if dirfd is available in <dirent.h>. */
+#define _GLIBCXX_HAVE_DIRFD 1
+
+/* Define to 1 if you have the <dlfcn.h> header file. */
+#define _GLIBCXX_HAVE_DLFCN_H 1
+
+/* Define to 1 if you have the <endian.h> header file. */
+#define _GLIBCXX_HAVE_ENDIAN_H 1
+
+/* Define to 1 if GCC 4.6 supported std::exception_ptr for the target */
+#define _GLIBCXX_HAVE_EXCEPTION_PTR_SINCE_GCC46 1
+
+/* Define to 1 if you have the <execinfo.h> header file. */
+#define _GLIBCXX_HAVE_EXECINFO_H 1
+
+/* Define to 1 if you have the `expf' function. */
+#define _GLIBCXX_HAVE_EXPF 1
+
+/* Define to 1 if you have the `expl' function. */
+#define _GLIBCXX_HAVE_EXPL 1
+
+/* Define to 1 if you have the `fabsf' function. */
+#define _GLIBCXX_HAVE_FABSF 1
+
+/* Define to 1 if you have the `fabsl' function. */
+#define _GLIBCXX_HAVE_FABSL 1
+
+/* Define to 1 if you have the <fcntl.h> header file. */
+#define _GLIBCXX_HAVE_FCNTL_H 1
+
+/* Define if fdopendir is available in <dirent.h>. */
+#define _GLIBCXX_HAVE_FDOPENDIR 1
+
+/* Define to 1 if you have the <fenv.h> header file. */
+#define _GLIBCXX_HAVE_FENV_H 1
+
+/* Define to 1 if you have the `finite' function. */
+#define _GLIBCXX_HAVE_FINITE 1
+
+/* Define to 1 if you have the `finitef' function. */
+#define _GLIBCXX_HAVE_FINITEF 1
+
+/* Define to 1 if you have the `finitel' function. */
+#define _GLIBCXX_HAVE_FINITEL 1
+
+/* Define to 1 if you have the <float.h> header file. */
+#define _GLIBCXX_HAVE_FLOAT_H 1
+
+/* Define to 1 if you have the `floorf' function. */
+#define _GLIBCXX_HAVE_FLOORF 1
+
+/* Define to 1 if you have the `floorl' function. */
+#define _GLIBCXX_HAVE_FLOORL 1
+
+/* Define to 1 if you have the `fmodf' function. */
+#define _GLIBCXX_HAVE_FMODF 1
+
+/* Define to 1 if you have the `fmodl' function. */
+#define _GLIBCXX_HAVE_FMODL 1
+
+/* Define to 1 if you have the `fpclass' function. */
+/* #undef _GLIBCXX_HAVE_FPCLASS */
+
+/* Define to 1 if you have the <fp.h> header file. */
+/* #undef _GLIBCXX_HAVE_FP_H */
+
+/* Define to 1 if you have the `frexpf' function. */
+#define _GLIBCXX_HAVE_FREXPF 1
+
+/* Define to 1 if you have the `frexpl' function. */
+#define _GLIBCXX_HAVE_FREXPL 1
+
+/* Define if getentropy is available in <unistd.h>. */
+#define _GLIBCXX_HAVE_GETENTROPY 1
+
+/* Define if _Unwind_GetIPInfo is available. */
+#define _GLIBCXX_HAVE_GETIPINFO 1
+
+/* Define if gets is available in <stdio.h> before C++14. */
+#define _GLIBCXX_HAVE_GETS 1
+
+/* Define to 1 if you have the `hypot' function. */
+#define _GLIBCXX_HAVE_HYPOT 1
+
+/* Define to 1 if you have the `hypotf' function. */
+#define _GLIBCXX_HAVE_HYPOTF 1
+
+/* Define to 1 if you have the `hypotl' function. */
+#define _GLIBCXX_HAVE_HYPOTL 1
+
+/* Define if you have the iconv() function. */
+#define _GLIBCXX_HAVE_ICONV 1
+
+/* Define to 1 if you have the <ieeefp.h> header file. */
+/* #undef _GLIBCXX_HAVE_IEEEFP_H */
+
+/* Define to 1 if you have the <inttypes.h> header file. */
+#define _GLIBCXX_HAVE_INTTYPES_H 1
+
+/* Define to 1 if you have the `isinf' function. */
+/* #undef _GLIBCXX_HAVE_ISINF */
+
+/* Define to 1 if you have the `isinff' function. */
+#define _GLIBCXX_HAVE_ISINFF 1
+
+/* Define to 1 if you have the `isinfl' function. */
+#define _GLIBCXX_HAVE_ISINFL 1
+
+/* Define to 1 if you have the `isnan' function. */
+/* #undef _GLIBCXX_HAVE_ISNAN */
+
+/* Define to 1 if you have the `isnanf' function. */
+#define _GLIBCXX_HAVE_ISNANF 1
+
+/* Define to 1 if you have the `isnanl' function. */
+#define _GLIBCXX_HAVE_ISNANL 1
+
+/* Defined if iswblank exists. */
+#define _GLIBCXX_HAVE_ISWBLANK 1
+
+/* Define if LC_MESSAGES is available in <locale.h>. */
+#define _GLIBCXX_HAVE_LC_MESSAGES 1
+
+/* Define to 1 if you have the `ldexpf' function. */
+#define _GLIBCXX_HAVE_LDEXPF 1
+
+/* Define to 1 if you have the `ldexpl' function. */
+#define _GLIBCXX_HAVE_LDEXPL 1
+
+/* Define to 1 if you have the <libintl.h> header file. */
+#define _GLIBCXX_HAVE_LIBINTL_H 1
+
+/* Only used in build directory testsuite_hooks.h. */
+#define _GLIBCXX_HAVE_LIMIT_AS 1
+
+/* Only used in build directory testsuite_hooks.h. */
+#define _GLIBCXX_HAVE_LIMIT_DATA 1
+
+/* Only used in build directory testsuite_hooks.h. */
+#define _GLIBCXX_HAVE_LIMIT_FSIZE 1
+
+/* Only used in build directory testsuite_hooks.h. */
+#define _GLIBCXX_HAVE_LIMIT_RSS 1
+
+/* Only used in build directory testsuite_hooks.h. */
+#define _GLIBCXX_HAVE_LIMIT_VMEM 0
+
+/* Define if link is available in <unistd.h>. */
+#define _GLIBCXX_HAVE_LINK 1
+
+/* Define to 1 if you have the <link.h> header file. */
+#define _GLIBCXX_HAVE_LINK_H 1
+
+/* Define if futex syscall is available. */
+#define _GLIBCXX_HAVE_LINUX_FUTEX 1
+
+/* Define to 1 if you have the <linux/random.h> header file. */
+#define _GLIBCXX_HAVE_LINUX_RANDOM_H 1
+
+/* Define to 1 if you have the <linux/types.h> header file. */
+#define _GLIBCXX_HAVE_LINUX_TYPES_H 1
+
+/* Define to 1 if you have the <locale.h> header file. */
+#define _GLIBCXX_HAVE_LOCALE_H 1
+
+/* Define to 1 if you have the `log10f' function. */
+#define _GLIBCXX_HAVE_LOG10F 1
+
+/* Define to 1 if you have the `log10l' function. */
+#define _GLIBCXX_HAVE_LOG10L 1
+
+/* Define to 1 if you have the `logf' function. */
+#define _GLIBCXX_HAVE_LOGF 1
+
+/* Define to 1 if you have the `logl' function. */
+#define _GLIBCXX_HAVE_LOGL 1
+
+/* Define to 1 if you have the <machine/endian.h> header file. */
+/* #undef _GLIBCXX_HAVE_MACHINE_ENDIAN_H */
+
+/* Define to 1 if you have the <machine/param.h> header file. */
+/* #undef _GLIBCXX_HAVE_MACHINE_PARAM_H */
+
+/* Define if mbstate_t exists in wchar.h. */
+#define _GLIBCXX_HAVE_MBSTATE_T 1
+
+/* Define to 1 if you have the `memalign' function. */
+#define _GLIBCXX_HAVE_MEMALIGN 1
+
+/* Define to 1 if you have the <memory.h> header file. */
+#define _GLIBCXX_HAVE_MEMORY_H 1
+
+/* Define to 1 if you have the `modf' function. */
+#define _GLIBCXX_HAVE_MODF 1
+
+/* Define to 1 if you have the `modff' function. */
+#define _GLIBCXX_HAVE_MODFF 1
+
+/* Define to 1 if you have the `modfl' function. */
+#define _GLIBCXX_HAVE_MODFL 1
+
+/* Define to 1 if you have the <nan.h> header file. */
+/* #undef _GLIBCXX_HAVE_NAN_H */
+
+/* Define to 1 if you have the <netdb.h> header file. */
+#define _GLIBCXX_HAVE_NETDB_H 1
+
+/* Define to 1 if you have the <netinet/in.h> header file. */
+#define _GLIBCXX_HAVE_NETINET_IN_H 1
+
+/* Define to 1 if you have the <netinet/tcp.h> header file. */
+#define _GLIBCXX_HAVE_NETINET_TCP_H 1
+
+/* Define if <math.h> defines obsolete isinf function. */
+/* #undef _GLIBCXX_HAVE_OBSOLETE_ISINF */
+
+/* Define if <math.h> defines obsolete isnan function. */
+/* #undef _GLIBCXX_HAVE_OBSOLETE_ISNAN */
+
+/* Define if openat is available in <fcntl.h>. */
+#define _GLIBCXX_HAVE_OPENAT 1
+
+/* Define if poll is available in <poll.h>. */
+#define _GLIBCXX_HAVE_POLL 1
+
+/* Define to 1 if you have the <poll.h> header file. */
+#define _GLIBCXX_HAVE_POLL_H 1
+
+/* Define to 1 if you have the `posix_memalign' function. */
+#define _GLIBCXX_HAVE_POSIX_MEMALIGN 1
+
+/* Define to 1 if POSIX Semaphores with sem_timedwait are available in
+   <semaphore.h>. */
+#define _GLIBCXX_HAVE_POSIX_SEMAPHORE 1
+
+/* Define to 1 if you have the `powf' function. */
+#define _GLIBCXX_HAVE_POWF 1
+
+/* Define to 1 if you have the `powl' function. */
+#define _GLIBCXX_HAVE_POWL 1
+
+/* Define to 1 if you have the `qfpclass' function. */
+/* #undef _GLIBCXX_HAVE_QFPCLASS */
+
+/* Define to 1 if you have the `quick_exit' function. */
+#define _GLIBCXX_HAVE_QUICK_EXIT 1
+
+/* Define if readlink is available in <unistd.h>. */
+#define _GLIBCXX_HAVE_READLINK 1
+
+/* Define to 1 if you have the `secure_getenv' function. */
+#define _GLIBCXX_HAVE_SECURE_GETENV 1
+
+/* Define to 1 if you have the `setenv' function. */
+#define _GLIBCXX_HAVE_SETENV 1
+
+/* Define to 1 if you have the `sincos' function. */
+#define _GLIBCXX_HAVE_SINCOS 1
+
+/* Define to 1 if you have the `sincosf' function. */
+#define _GLIBCXX_HAVE_SINCOSF 1
+
+/* Define to 1 if you have the `sincosl' function. */
+#define _GLIBCXX_HAVE_SINCOSL 1
+
+/* Define to 1 if you have the `sinf' function. */
+#define _GLIBCXX_HAVE_SINF 1
+
+/* Define to 1 if you have the `sinhf' function. */
+#define _GLIBCXX_HAVE_SINHF 1
+
+/* Define to 1 if you have the `sinhl' function. */
+#define _GLIBCXX_HAVE_SINHL 1
+
+/* Define to 1 if you have the `sinl' function. */
+#define _GLIBCXX_HAVE_SINL 1
+
+/* Defined if sleep exists. */
+/* #undef _GLIBCXX_HAVE_SLEEP */
+
+/* Define to 1 if you have the `sockatmark' function. */
+#define _GLIBCXX_HAVE_SOCKATMARK 1
+
+/* Define to 1 if you have the `sqrtf' function. */
+#define _GLIBCXX_HAVE_SQRTF 1
+
+/* Define to 1 if you have the `sqrtl' function. */
+#define _GLIBCXX_HAVE_SQRTL 1
+
+/* Define if the <stacktrace> header is supported. */
+/* #undef _GLIBCXX_HAVE_STACKTRACE */
+
+/* Define to 1 if you have the <stdalign.h> header file. */
+#define _GLIBCXX_HAVE_STDALIGN_H 1
+
+/* Define to 1 if you have the <stdbool.h> header file. */
+#define _GLIBCXX_HAVE_STDBOOL_H 1
+
+/* Define to 1 if you have the <stdint.h> header file. */
+#define _GLIBCXX_HAVE_STDINT_H 1
+
+/* Define to 1 if you have the <stdlib.h> header file. */
+#define _GLIBCXX_HAVE_STDLIB_H 1
+
+/* Define if strerror_l is available in <string.h>. */
+#define _GLIBCXX_HAVE_STRERROR_L 1
+
+/* Define if strerror_r is available in <string.h>. */
+#define _GLIBCXX_HAVE_STRERROR_R 1
+
+/* Define to 1 if you have the <strings.h> header file. */
+#define _GLIBCXX_HAVE_STRINGS_H 1
+
+/* Define to 1 if you have the <string.h> header file. */
+#define _GLIBCXX_HAVE_STRING_H 1
+
+/* Define to 1 if you have the `strtof' function. */
+#define _GLIBCXX_HAVE_STRTOF 1
+
+/* Define to 1 if you have the `strtold' function. */
+#define _GLIBCXX_HAVE_STRTOLD 1
+
+/* Define to 1 if `d_type' is a member of `struct dirent'. */
+#define _GLIBCXX_HAVE_STRUCT_DIRENT_D_TYPE 1
+
+/* Define if strxfrm_l is available in <string.h>. */
+#define _GLIBCXX_HAVE_STRXFRM_L 1
+
+/* Define if symlink is available in <unistd.h>. */
+#define _GLIBCXX_HAVE_SYMLINK 1
+
+/* Define to 1 if the target runtime linker supports binding the same symbol
+   to different versions. */
+#define _GLIBCXX_HAVE_SYMVER_SYMBOL_RENAMING_RUNTIME_SUPPORT 1
+
+/* Define to 1 if you have the <sys/filio.h> header file. */
+/* #undef _GLIBCXX_HAVE_SYS_FILIO_H */
+
+/* Define to 1 if you have the <sys/ioctl.h> header file. */
+#define _GLIBCXX_HAVE_SYS_IOCTL_H 1
+
+/* Define to 1 if you have the <sys/ipc.h> header file. */
+#define _GLIBCXX_HAVE_SYS_IPC_H 1
+
+/* Define to 1 if you have the <sys/isa_defs.h> header file. */
+/* #undef _GLIBCXX_HAVE_SYS_ISA_DEFS_H */
+
+/* Define to 1 if you have the <sys/machine.h> header file. */
+/* #undef _GLIBCXX_HAVE_SYS_MACHINE_H */
+
+/* Define to 1 if you have the <sys/mman.h> header file. */
+/* #undef _GLIBCXX_HAVE_SYS_MMAN_H */
+
+/* Define to 1 if you have the <sys/param.h> header file. */
+#define _GLIBCXX_HAVE_SYS_PARAM_H 1
+
+/* Define to 1 if you have the <sys/resource.h> header file. */
+#define _GLIBCXX_HAVE_SYS_RESOURCE_H 1
+
+/* Define to 1 if you have a suitable <sys/sdt.h> header file */
+/* #undef _GLIBCXX_HAVE_SYS_SDT_H */
+
+/* Define to 1 if you have the <sys/sem.h> header file. */
+#define _GLIBCXX_HAVE_SYS_SEM_H 1
+
+/* Define to 1 if you have the <sys/socket.h> header file. */
+#define _GLIBCXX_HAVE_SYS_SOCKET_H 1
+
+/* Define to 1 if you have the <sys/statvfs.h> header file. */
+#define _GLIBCXX_HAVE_SYS_STATVFS_H 1
+
+/* Define to 1 if you have the <sys/stat.h> header file. */
+#define _GLIBCXX_HAVE_SYS_STAT_H 1
+
+/* Define to 1 if you have the <sys/sysinfo.h> header file. */
+#define _GLIBCXX_HAVE_SYS_SYSINFO_H 1
+
+/* Define to 1 if you have the <sys/time.h> header file. */
+#define _GLIBCXX_HAVE_SYS_TIME_H 1
+
+/* Define to 1 if you have the <sys/types.h> header file. */
+#define _GLIBCXX_HAVE_SYS_TYPES_H 1
+
+/* Define to 1 if you have the <sys/uio.h> header file. */
+#define _GLIBCXX_HAVE_SYS_UIO_H 1
+
+/* Define if S_IFREG is available in <sys/stat.h>. */
+/* #undef _GLIBCXX_HAVE_S_IFREG */
+
+/* Define if S_ISREG is available in <sys/stat.h>. */
+#define _GLIBCXX_HAVE_S_ISREG 1
+
+/* Define to 1 if you have the `tanf' function. */
+#define _GLIBCXX_HAVE_TANF 1
+
+/* Define to 1 if you have the `tanhf' function. */
+#define _GLIBCXX_HAVE_TANHF 1
+
+/* Define to 1 if you have the `tanhl' function. */
+#define _GLIBCXX_HAVE_TANHL 1
+
+/* Define to 1 if you have the `tanl' function. */
+#define _GLIBCXX_HAVE_TANL 1
+
+/* Define to 1 if you have the <tgmath.h> header file. */
+#define _GLIBCXX_HAVE_TGMATH_H 1
+
+/* Define to 1 if you have the `timespec_get' function. */
+#define _GLIBCXX_HAVE_TIMESPEC_GET 1
+
+/* Define to 1 if the target supports thread-local storage. */
+#define _GLIBCXX_HAVE_TLS 1
+
+/* Define if truncate is available in <unistd.h>. */
+#define _GLIBCXX_HAVE_TRUNCATE 1
+
+/* Define to 1 if you have the <uchar.h> header file. */
+#define _GLIBCXX_HAVE_UCHAR_H 1
+
+/* Define to 1 if you have the <unistd.h> header file. */
+#define _GLIBCXX_HAVE_UNISTD_H 1
+
+/* Define if unlinkat is available in <fcntl.h>. */
+#define _GLIBCXX_HAVE_UNLINKAT 1
+
+/* Define to 1 if you have the `uselocale' function. */
+#define _GLIBCXX_HAVE_USELOCALE 1
+
+/* Defined if usleep exists. */
+/* #undef _GLIBCXX_HAVE_USLEEP */
+
+/* Define to 1 if you have the <utime.h> header file. */
+#define _GLIBCXX_HAVE_UTIME_H 1
+
+/* Defined if vfwscanf exists. */
+#define _GLIBCXX_HAVE_VFWSCANF 1
+
+/* Defined if vswscanf exists. */
+#define _GLIBCXX_HAVE_VSWSCANF 1
+
+/* Defined if vwscanf exists. */
+#define _GLIBCXX_HAVE_VWSCANF 1
+
+/* Define to 1 if you have the <wchar.h> header file. */
+#define _GLIBCXX_HAVE_WCHAR_H 1
+
+/* Defined if wcstof exists. */
+#define _GLIBCXX_HAVE_WCSTOF 1
+
+/* Define to 1 if you have the <wctype.h> header file. */
+#define _GLIBCXX_HAVE_WCTYPE_H 1
+
+/* Defined if Sleep exists. */
+/* #undef _GLIBCXX_HAVE_WIN32_SLEEP */
+
+/* Define if writev is available in <sys/uio.h>. */
+#define _GLIBCXX_HAVE_WRITEV 1
+
+/* Define to 1 if you have the <xlocale.h> header file. */
+/* #undef _GLIBCXX_HAVE_XLOCALE_H */
+
+/* Define to 1 if you have the `_acosf' function. */
+/* #undef _GLIBCXX_HAVE__ACOSF */
+
+/* Define to 1 if you have the `_acosl' function. */
+/* #undef _GLIBCXX_HAVE__ACOSL */
+
+/* Define to 1 if you have the `_aligned_malloc' function. */
+/* #undef _GLIBCXX_HAVE__ALIGNED_MALLOC */
+
+/* Define to 1 if you have the `_asinf' function. */
+/* #undef _GLIBCXX_HAVE__ASINF */
+
+/* Define to 1 if you have the `_asinl' function. */
+/* #undef _GLIBCXX_HAVE__ASINL */
+
+/* Define to 1 if you have the `_atan2f' function. */
+/* #undef _GLIBCXX_HAVE__ATAN2F */
+
+/* Define to 1 if you have the `_atan2l' function. */
+/* #undef _GLIBCXX_HAVE__ATAN2L */
+
+/* Define to 1 if you have the `_atanf' function. */
+/* #undef _GLIBCXX_HAVE__ATANF */
+
+/* Define to 1 if you have the `_atanl' function. */
+/* #undef _GLIBCXX_HAVE__ATANL */
+
+/* Define to 1 if you have the `_ceilf' function. */
+/* #undef _GLIBCXX_HAVE__CEILF */
+
+/* Define to 1 if you have the `_ceill' function. */
+/* #undef _GLIBCXX_HAVE__CEILL */
+
+/* Define to 1 if you have the `_cosf' function. */
+/* #undef _GLIBCXX_HAVE__COSF */
+
+/* Define to 1 if you have the `_coshf' function. */
+/* #undef _GLIBCXX_HAVE__COSHF */
+
+/* Define to 1 if you have the `_coshl' function. */
+/* #undef _GLIBCXX_HAVE__COSHL */
+
+/* Define to 1 if you have the `_cosl' function. */
+/* #undef _GLIBCXX_HAVE__COSL */
+
+/* Define to 1 if you have the `_expf' function. */
+/* #undef _GLIBCXX_HAVE__EXPF */
+
+/* Define to 1 if you have the `_expl' function. */
+/* #undef _GLIBCXX_HAVE__EXPL */
+
+/* Define to 1 if you have the `_fabsf' function. */
+/* #undef _GLIBCXX_HAVE__FABSF */
+
+/* Define to 1 if you have the `_fabsl' function. */
+/* #undef _GLIBCXX_HAVE__FABSL */
+
+/* Define to 1 if you have the `_finite' function. */
+/* #undef _GLIBCXX_HAVE__FINITE */
+
+/* Define to 1 if you have the `_finitef' function. */
+/* #undef _GLIBCXX_HAVE__FINITEF */
+
+/* Define to 1 if you have the `_finitel' function. */
+/* #undef _GLIBCXX_HAVE__FINITEL */
+
+/* Define to 1 if you have the `_floorf' function. */
+/* #undef _GLIBCXX_HAVE__FLOORF */
+
+/* Define to 1 if you have the `_floorl' function. */
+/* #undef _GLIBCXX_HAVE__FLOORL */
+
+/* Define to 1 if you have the `_fmodf' function. */
+/* #undef _GLIBCXX_HAVE__FMODF */
+
+/* Define to 1 if you have the `_fmodl' function. */
+/* #undef _GLIBCXX_HAVE__FMODL */
+
+/* Define to 1 if you have the `_fpclass' function. */
+/* #undef _GLIBCXX_HAVE__FPCLASS */
+
+/* Define to 1 if you have the `_frexpf' function. */
+/* #undef _GLIBCXX_HAVE__FREXPF */
+
+/* Define to 1 if you have the `_frexpl' function. */
+/* #undef _GLIBCXX_HAVE__FREXPL */
+
+/* Define to 1 if you have the `_hypot' function. */
+/* #undef _GLIBCXX_HAVE__HYPOT */
+
+/* Define to 1 if you have the `_hypotf' function. */
+/* #undef _GLIBCXX_HAVE__HYPOTF */
+
+/* Define to 1 if you have the `_hypotl' function. */
+/* #undef _GLIBCXX_HAVE__HYPOTL */
+
+/* Define to 1 if you have the `_isinf' function. */
+/* #undef _GLIBCXX_HAVE__ISINF */
+
+/* Define to 1 if you have the `_isinff' function. */
+/* #undef _GLIBCXX_HAVE__ISINFF */
+
+/* Define to 1 if you have the `_isinfl' function. */
+/* #undef _GLIBCXX_HAVE__ISINFL */
+
+/* Define to 1 if you have the `_isnan' function. */
+/* #undef _GLIBCXX_HAVE__ISNAN */
+
+/* Define to 1 if you have the `_isnanf' function. */
+/* #undef _GLIBCXX_HAVE__ISNANF */
+
+/* Define to 1 if you have the `_isnanl' function. */
+/* #undef _GLIBCXX_HAVE__ISNANL */
+
+/* Define to 1 if you have the `_ldexpf' function. */
+/* #undef _GLIBCXX_HAVE__LDEXPF */
+
+/* Define to 1 if you have the `_ldexpl' function. */
+/* #undef _GLIBCXX_HAVE__LDEXPL */
+
+/* Define to 1 if you have the `_log10f' function. */
+/* #undef _GLIBCXX_HAVE__LOG10F */
+
+/* Define to 1 if you have the `_log10l' function. */
+/* #undef _GLIBCXX_HAVE__LOG10L */
+
+/* Define to 1 if you have the `_logf' function. */
+/* #undef _GLIBCXX_HAVE__LOGF */
+
+/* Define to 1 if you have the `_logl' function. */
+/* #undef _GLIBCXX_HAVE__LOGL */
+
+/* Define to 1 if you have the `_modf' function. */
+/* #undef _GLIBCXX_HAVE__MODF */
+
+/* Define to 1 if you have the `_modff' function. */
+/* #undef _GLIBCXX_HAVE__MODFF */
+
+/* Define to 1 if you have the `_modfl' function. */
+/* #undef _GLIBCXX_HAVE__MODFL */
+
+/* Define to 1 if you have the `_powf' function. */
+/* #undef _GLIBCXX_HAVE__POWF */
+
+/* Define to 1 if you have the `_powl' function. */
+/* #undef _GLIBCXX_HAVE__POWL */
+
+/* Define to 1 if you have the `_qfpclass' function. */
+/* #undef _GLIBCXX_HAVE__QFPCLASS */
+
+/* Define to 1 if you have the `_sincos' function. */
+/* #undef _GLIBCXX_HAVE__SINCOS */
+
+/* Define to 1 if you have the `_sincosf' function. */
+/* #undef _GLIBCXX_HAVE__SINCOSF */
+
+/* Define to 1 if you have the `_sincosl' function. */
+/* #undef _GLIBCXX_HAVE__SINCOSL */
+
+/* Define to 1 if you have the `_sinf' function. */
+/* #undef _GLIBCXX_HAVE__SINF */
+
+/* Define to 1 if you have the `_sinhf' function. */
+/* #undef _GLIBCXX_HAVE__SINHF */
+
+/* Define to 1 if you have the `_sinhl' function. */
+/* #undef _GLIBCXX_HAVE__SINHL */
+
+/* Define to 1 if you have the `_sinl' function. */
+/* #undef _GLIBCXX_HAVE__SINL */
+
+/* Define to 1 if you have the `_sqrtf' function. */
+/* #undef _GLIBCXX_HAVE__SQRTF */
+
+/* Define to 1 if you have the `_sqrtl' function. */
+/* #undef _GLIBCXX_HAVE__SQRTL */
+
+/* Define to 1 if you have the `_tanf' function. */
+/* #undef _GLIBCXX_HAVE__TANF */
+
+/* Define to 1 if you have the `_tanhf' function. */
+/* #undef _GLIBCXX_HAVE__TANHF */
+
+/* Define to 1 if you have the `_tanhl' function. */
+/* #undef _GLIBCXX_HAVE__TANHL */
+
+/* Define to 1 if you have the `_tanl' function. */
+/* #undef _GLIBCXX_HAVE__TANL */
+
+/* Define to 1 if you have the `_wfopen' function. */
+/* #undef _GLIBCXX_HAVE__WFOPEN */
+
+/* Define to 1 if you have the `__cxa_thread_atexit' function. */
+/* #undef _GLIBCXX_HAVE___CXA_THREAD_ATEXIT */
+
+/* Define to 1 if you have the `__cxa_thread_atexit_impl' function. */
+#define _GLIBCXX_HAVE___CXA_THREAD_ATEXIT_IMPL 1
+
+/* Define as const if the declaration of iconv() needs const. */
+#define _GLIBCXX_ICONV_CONST 
+
+/* Define to the sub-directory in which libtool stores uninstalled libraries.
+   */
+#define _GLIBCXX_LT_OBJDIR ".libs/"
+
+/* Name of package */
+/* #undef _GLIBCXX_PACKAGE */
+
+/* Define to the address where bug reports for this package should be sent. */
+#define _GLIBCXX_PACKAGE_BUGREPORT ""
+
+/* Define to the full name of this package. */
+#define _GLIBCXX_PACKAGE_NAME "package-unused"
+
+/* Define to the full name and version of this package. */
+#define _GLIBCXX_PACKAGE_STRING "package-unused version-unused"
+
+/* Define to the one symbol short name of this package. */
+#define _GLIBCXX_PACKAGE_TARNAME "libstdc++"
+
+/* Define to the home page for this package. */
+#define _GLIBCXX_PACKAGE_URL ""
+
+/* Define to the version of this package. */
+#define _GLIBCXX_PACKAGE__GLIBCXX_VERSION "version-unused"
+
+/* The size of `char', as computed by sizeof. */
+/* #undef SIZEOF_CHAR */
+
+/* The size of `int', as computed by sizeof. */
+/* #undef SIZEOF_INT */
+
+/* The size of `long', as computed by sizeof. */
+/* #undef SIZEOF_LONG */
+
+/* The size of `short', as computed by sizeof. */
+/* #undef SIZEOF_SHORT */
+
+/* The size of `void *', as computed by sizeof. */
+/* #undef SIZEOF_VOID_P */
+
+/* Define to 1 if you have the ANSI C header files. */
+#define _GLIBCXX_STDC_HEADERS 1
+
+/* Version number of package */
+/* #undef _GLIBCXX_VERSION */
+
+/* Enable large inode numbers on Mac OS X 10.5.  */
+#ifndef _GLIBCXX_DARWIN_USE_64_BIT_INODE
+# define _GLIBCXX_DARWIN_USE_64_BIT_INODE 1
+#endif
+
+/* Number of bits in a file offset, on hosts where this is settable. */
+/* #undef _GLIBCXX_FILE_OFFSET_BITS */
+
+/* Define if C99 functions in <complex.h> should be used in <complex> for
+   C++11. Using compiler builtins for these functions requires corresponding
+   C99 library functions to be present. */
+#define _GLIBCXX11_USE_C99_COMPLEX 1
+
+/* Define if C99 functions or macros in <math.h> should be imported in <cmath>
+   in namespace std for C++11. */
+#define _GLIBCXX11_USE_C99_MATH 1
+
+/* Define if C99 functions or macros in <stdio.h> should be imported in
+   <cstdio> in namespace std for C++11. */
+#define _GLIBCXX11_USE_C99_STDIO 1
+
+/* Define if C99 functions or macros in <stdlib.h> should be imported in
+   <cstdlib> in namespace std for C++11. */
+#define _GLIBCXX11_USE_C99_STDLIB 1
+
+/* Define if C99 functions or macros in <wchar.h> should be imported in
+   <cwchar> in namespace std for C++11. */
+#define _GLIBCXX11_USE_C99_WCHAR 1
+
+/* Define if C99 functions in <complex.h> should be used in <complex> for
+   C++98. Using compiler builtins for these functions requires corresponding
+   C99 library functions to be present. */
+#define _GLIBCXX98_USE_C99_COMPLEX 1
+
+/* Define if C99 functions or macros in <math.h> should be imported in <cmath>
+   in namespace std for C++98. */
+#define _GLIBCXX98_USE_C99_MATH 1
+
+/* Define if C99 functions or macros in <stdio.h> should be imported in
+   <cstdio> in namespace std for C++98. */
+#define _GLIBCXX98_USE_C99_STDIO 1
+
+/* Define if C99 functions or macros in <stdlib.h> should be imported in
+   <cstdlib> in namespace std for C++98. */
+#define _GLIBCXX98_USE_C99_STDLIB 1
+
+/* Define if C99 functions or macros in <wchar.h> should be imported in
+   <cwchar> in namespace std for C++98. */
+#define _GLIBCXX98_USE_C99_WCHAR 1
+
+/* Define if the compiler supports C++11 atomics. */
+#define _GLIBCXX_ATOMIC_BUILTINS 1
+
+/* Define to use concept checking code from the boost libraries. */
+/* #undef _GLIBCXX_CONCEPT_CHECKS */
+
+/* Define to 1 if a fully dynamic basic_string is wanted, 0 to disable,
+   undefined for platform defaults */
+#define _GLIBCXX_FULLY_DYNAMIC_STRING 0
+
+/* Define if gthreads library is available. */
+#define _GLIBCXX_HAS_GTHREADS 1
+
+/* Define to 1 if a full hosted library is built, or 0 if freestanding. */
+#define _GLIBCXX_HOSTED 1
+
+/* Define if compatibility should be provided for alternative 128-bit long
+   double formats. */
+
+/* Define if compatibility should be provided for -mlong-double-64. */
+
+/* Define to the letter to which size_t is mangled. */
+#define _GLIBCXX_MANGLE_SIZE_T m
+
+/* Define if C99 llrint and llround functions are missing from <math.h>. */
+/* #undef _GLIBCXX_NO_C99_ROUNDING_FUNCS */
+
+/* Defined if no way to sleep is available. */
+/* #undef _GLIBCXX_NO_SLEEP */
+
+/* Define if ptrdiff_t is int. */
+/* #undef _GLIBCXX_PTRDIFF_T_IS_INT */
+
+/* Define if using setrlimit to set resource limits during "make check" */
+#define _GLIBCXX_RES_LIMITS 1
+
+/* Define if size_t is unsigned int. */
+/* #undef _GLIBCXX_SIZE_T_IS_UINT */
+
+/* Define to the value of the EOF integer constant. */
+#define _GLIBCXX_STDIO_EOF -1
+
+/* Define to the value of the SEEK_CUR integer constant. */
+#define _GLIBCXX_STDIO_SEEK_CUR 1
+
+/* Define to the value of the SEEK_END integer constant. */
+#define _GLIBCXX_STDIO_SEEK_END 2
+
+/* Define to use symbol versioning in the shared library. */
+#define _GLIBCXX_SYMVER 1
+
+/* Define to use darwin versioning in the shared library. */
+/* #undef _GLIBCXX_SYMVER_DARWIN */
+
+/* Define to use GNU versioning in the shared library. */
+#define _GLIBCXX_SYMVER_GNU 1
+
+/* Define to use GNU namespace versioning in the shared library. */
+/* #undef _GLIBCXX_SYMVER_GNU_NAMESPACE */
+
+/* Define to use Sun versioning in the shared library. */
+/* #undef _GLIBCXX_SYMVER_SUN */
+
+/* Define if C11 functions in <uchar.h> should be imported into namespace std
+   in <cuchar>. */
+#define _GLIBCXX_USE_C11_UCHAR_CXX11 1
+
+/* Define if C99 functions or macros from <wchar.h>, <math.h>, <complex.h>,
+   <stdio.h>, and <stdlib.h> can be used or exposed. */
+#define _GLIBCXX_USE_C99 1
+
+/* Define if C99 functions in <complex.h> should be used in <tr1/complex>.
+   Using compiler builtins for these functions requires corresponding C99
+   library functions to be present. */
+#define _GLIBCXX_USE_C99_COMPLEX_TR1 1
+
+/* Define if C99 functions in <ctype.h> should be imported in <tr1/cctype> in
+   namespace std::tr1. */
+#define _GLIBCXX_USE_C99_CTYPE_TR1 1
+
+/* Define if C99 functions in <fenv.h> should be imported in <tr1/cfenv> in
+   namespace std::tr1. */
+#define _GLIBCXX_USE_C99_FENV_TR1 1
+
+/* Define if C99 functions in <inttypes.h> should be imported in
+   <tr1/cinttypes> in namespace std::tr1. */
+#define _GLIBCXX_USE_C99_INTTYPES_TR1 1
+
+/* Define if wchar_t C99 functions in <inttypes.h> should be imported in
+   <tr1/cinttypes> in namespace std::tr1. */
+#define _GLIBCXX_USE_C99_INTTYPES_WCHAR_T_TR1 1
+
+/* Define if C99 functions or macros in <math.h> should be imported in
+   <tr1/cmath> in namespace std::tr1. */
+#define _GLIBCXX_USE_C99_MATH_TR1 1
+
+/* Define if C99 types in <stdint.h> should be imported in <tr1/cstdint> in
+   namespace std::tr1. */
+#define _GLIBCXX_USE_C99_STDINT_TR1 1
+
+/* Defined if clock_gettime syscall has monotonic and realtime clock support.
+   */
+/* #undef _GLIBCXX_USE_CLOCK_GETTIME_SYSCALL */
+
+/* Defined if clock_gettime has monotonic clock support. */
+#define _GLIBCXX_USE_CLOCK_MONOTONIC 1
+
+/* Defined if clock_gettime has realtime clock support. */
+#define _GLIBCXX_USE_CLOCK_REALTIME 1
+
+/* Define if ISO/IEC TR 24733 decimal floating point types are supported on
+   this host. */
+#define _GLIBCXX_USE_DECIMAL_FLOAT 1
+
+/* Define if /dev/random and /dev/urandom are available for
+   std::random_device. */
+#define _GLIBCXX_USE_DEV_RANDOM 1
+
+/* Define if fchmod is available in <sys/stat.h>. */
+#define _GLIBCXX_USE_FCHMOD 1
+
+/* Define if fchmodat is available in <sys/stat.h>. */
+#define _GLIBCXX_USE_FCHMODAT 1
+
+/* Defined if gettimeofday is available. */
+#define _GLIBCXX_USE_GETTIMEOFDAY 1
+
+/* Define if get_nprocs is available in <sys/sysinfo.h>. */
+#define _GLIBCXX_USE_GET_NPROCS 1
+
+/* Define if LFS support is available. */
+#define _GLIBCXX_USE_LFS 1
+
+/* Define if code specialized for long long should be used. */
+#define _GLIBCXX_USE_LONG_LONG 1
+
+/* Define if lstat is available in <sys/stat.h>. */
+#define _GLIBCXX_USE_LSTAT 1
+
+/* Defined if nanosleep is available. */
+#define _GLIBCXX_USE_NANOSLEEP 1
+
+/* Define if NLS translations are to be used. */
+#define _GLIBCXX_USE_NLS 1
+
+/* Define if pthreads_num_processors_np is available in <pthread.h>. */
+/* #undef _GLIBCXX_USE_PTHREADS_NUM_PROCESSORS_NP */
+
+/* Define if pthread_cond_clockwait is available in <pthread.h>. */
+#define _GLIBCXX_USE_PTHREAD_COND_CLOCKWAIT 1
+
+/* Define if pthread_mutex_clocklock is available in <pthread.h>. */
+#define _GLIBCXX_USE_PTHREAD_MUTEX_CLOCKLOCK 1
+
+/* Define if pthread_rwlock_clockrdlock and pthread_rwlock_clockwrlock are
+   available in <pthread.h>. */
+#define _GLIBCXX_USE_PTHREAD_RWLOCK_CLOCKLOCK 1
+
+/* Define if POSIX read/write locks are available in <gthr.h>. */
+#define _GLIBCXX_USE_PTHREAD_RWLOCK_T 1
+
+/* Define if /dev/random and /dev/urandom are available for the random_device
+   of TR1 (Chapter 5.1). */
+#define _GLIBCXX_USE_RANDOM_TR1 1
+
+/* Define if usable realpath is available in <stdlib.h>. */
+#define _GLIBCXX_USE_REALPATH 1
+
+/* Defined if sched_yield is available. */
+#define _GLIBCXX_USE_SCHED_YIELD 1
+
+/* Define if _SC_NPROCESSORS_ONLN is available in <unistd.h>. */
+#define _GLIBCXX_USE_SC_NPROCESSORS_ONLN 1
+
+/* Define if _SC_NPROC_ONLN is available in <unistd.h>. */
+/* #undef _GLIBCXX_USE_SC_NPROC_ONLN */
+
+/* Define if sendfile is available in <sys/sendfile.h>. */
+#define _GLIBCXX_USE_SENDFILE 1
+
+/* Define to restrict std::__basic_file<> to stdio APIs. */
+/* #undef _GLIBCXX_USE_STDIO_PURE */
+
+/* Define if struct stat has timespec members. */
+#define _GLIBCXX_USE_ST_MTIM 1
+
+/* Define if sysctl(), CTL_HW and HW_NCPU are available in <sys/sysctl.h>. */
+/* #undef _GLIBCXX_USE_SYSCTL_HW_NCPU */
+
+/* Define if obsolescent tmpnam is available in <stdio.h>. */
+#define _GLIBCXX_USE_TMPNAM 1
+
+/* Define if c8rtomb and mbrtoc8 functions in <uchar.h> should be imported
+   into namespace std in <cuchar> for C++20. */
+/* #undef _GLIBCXX_USE_UCHAR_C8RTOMB_MBRTOC8_CXX20 */
+
+/* Define if c8rtomb and mbrtoc8 functions in <uchar.h> should be imported
+   into namespace std in <cuchar> for -fchar8_t. */
+/* #undef _GLIBCXX_USE_UCHAR_C8RTOMB_MBRTOC8_FCHAR8_T */
+
+/* Define if utime is available in <utime.h>. */
+#define _GLIBCXX_USE_UTIME 1
+
+/* Define if utimensat and UTIME_OMIT are available in <sys/stat.h> and
+   AT_FDCWD in <fcntl.h>. */
+#define _GLIBCXX_USE_UTIMENSAT 1
+
+/* Define if code specialized for wchar_t should be used. */
+#define _GLIBCXX_USE_WCHAR_T 1
+
+/* Define to 1 if a verbose library is built, or 0 otherwise. */
+#define _GLIBCXX_VERBOSE 1
+
+/* Defined if as can handle rdrand. */
+#define _GLIBCXX_X86_RDRAND 1
+
+/* Defined if as can handle rdseed. */
+#define _GLIBCXX_X86_RDSEED 1
+
+/* Define to 1 if mutex_timedlock is available. */
+#define _GTHREAD_USE_MUTEX_TIMEDLOCK 1
+
+/* Define for large files, on AIX-style hosts. */
+/* #undef _GLIBCXX_LARGE_FILES */
+
+/* Define if all C++11 floating point overloads are available in <math.h>.  */
+#if __cplusplus >= 201103L
+/* #undef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP */
+#endif
+
+/* Define if all C++11 integral type overloads are available in <math.h>.  */
+#if __cplusplus >= 201103L
+/* #undef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT */
+#endif
+
+#if defined (_GLIBCXX_HAVE__ACOSF) && ! defined (_GLIBCXX_HAVE_ACOSF)
+# define _GLIBCXX_HAVE_ACOSF 1
+# define acosf _acosf
+#endif
+
+#if defined (_GLIBCXX_HAVE__ACOSL) && ! defined (_GLIBCXX_HAVE_ACOSL)
+# define _GLIBCXX_HAVE_ACOSL 1
+# define acosl _acosl
+#endif
+
+#if defined (_GLIBCXX_HAVE__ASINF) && ! defined (_GLIBCXX_HAVE_ASINF)
+# define _GLIBCXX_HAVE_ASINF 1
+# define asinf _asinf
+#endif
+
+#if defined (_GLIBCXX_HAVE__ASINL) && ! defined (_GLIBCXX_HAVE_ASINL)
+# define _GLIBCXX_HAVE_ASINL 1
+# define asinl _asinl
+#endif
+
+#if defined (_GLIBCXX_HAVE__ATAN2F) && ! defined (_GLIBCXX_HAVE_ATAN2F)
+# define _GLIBCXX_HAVE_ATAN2F 1
+# define atan2f _atan2f
+#endif
+
+#if defined (_GLIBCXX_HAVE__ATAN2L) && ! defined (_GLIBCXX_HAVE_ATAN2L)
+# define _GLIBCXX_HAVE_ATAN2L 1
+# define atan2l _atan2l
+#endif
+
+#if defined (_GLIBCXX_HAVE__ATANF) && ! defined (_GLIBCXX_HAVE_ATANF)
+# define _GLIBCXX_HAVE_ATANF 1
+# define atanf _atanf
+#endif
+
+#if defined (_GLIBCXX_HAVE__ATANL) && ! defined (_GLIBCXX_HAVE_ATANL)
+# define _GLIBCXX_HAVE_ATANL 1
+# define atanl _atanl
+#endif
+
+#if defined (_GLIBCXX_HAVE__CEILF) && ! defined (_GLIBCXX_HAVE_CEILF)
+# define _GLIBCXX_HAVE_CEILF 1
+# define ceilf _ceilf
+#endif
+
+#if defined (_GLIBCXX_HAVE__CEILL) && ! defined (_GLIBCXX_HAVE_CEILL)
+# define _GLIBCXX_HAVE_CEILL 1
+# define ceill _ceill
+#endif
+
+#if defined (_GLIBCXX_HAVE__COSF) && ! defined (_GLIBCXX_HAVE_COSF)
+# define _GLIBCXX_HAVE_COSF 1
+# define cosf _cosf
+#endif
+
+#if defined (_GLIBCXX_HAVE__COSHF) && ! defined (_GLIBCXX_HAVE_COSHF)
+# define _GLIBCXX_HAVE_COSHF 1
+# define coshf _coshf
+#endif
+
+#if defined (_GLIBCXX_HAVE__COSHL) && ! defined (_GLIBCXX_HAVE_COSHL)
+# define _GLIBCXX_HAVE_COSHL 1
+# define coshl _coshl
+#endif
+
+#if defined (_GLIBCXX_HAVE__COSL) && ! defined (_GLIBCXX_HAVE_COSL)
+# define _GLIBCXX_HAVE_COSL 1
+# define cosl _cosl
+#endif
+
+#if defined (_GLIBCXX_HAVE__EXPF) && ! defined (_GLIBCXX_HAVE_EXPF)
+# define _GLIBCXX_HAVE_EXPF 1
+# define expf _expf
+#endif
+
+#if defined (_GLIBCXX_HAVE__EXPL) && ! defined (_GLIBCXX_HAVE_EXPL)
+# define _GLIBCXX_HAVE_EXPL 1
+# define expl _expl
+#endif
+
+#if defined (_GLIBCXX_HAVE__FABSF) && ! defined (_GLIBCXX_HAVE_FABSF)
+# define _GLIBCXX_HAVE_FABSF 1
+# define fabsf _fabsf
+#endif
+
+#if defined (_GLIBCXX_HAVE__FABSL) && ! defined (_GLIBCXX_HAVE_FABSL)
+# define _GLIBCXX_HAVE_FABSL 1
+# define fabsl _fabsl
+#endif
+
+#if defined (_GLIBCXX_HAVE__FINITE) && ! defined (_GLIBCXX_HAVE_FINITE)
+# define _GLIBCXX_HAVE_FINITE 1
+# define finite _finite
+#endif
+
+#if defined (_GLIBCXX_HAVE__FINITEF) && ! defined (_GLIBCXX_HAVE_FINITEF)
+# define _GLIBCXX_HAVE_FINITEF 1
+# define finitef _finitef
+#endif
+
+#if defined (_GLIBCXX_HAVE__FINITEL) && ! defined (_GLIBCXX_HAVE_FINITEL)
+# define _GLIBCXX_HAVE_FINITEL 1
+# define finitel _finitel
+#endif
+
+#if defined (_GLIBCXX_HAVE__FLOORF) && ! defined (_GLIBCXX_HAVE_FLOORF)
+# define _GLIBCXX_HAVE_FLOORF 1
+# define floorf _floorf
+#endif
+
+#if defined (_GLIBCXX_HAVE__FLOORL) && ! defined (_GLIBCXX_HAVE_FLOORL)
+# define _GLIBCXX_HAVE_FLOORL 1
+# define floorl _floorl
+#endif
+
+#if defined (_GLIBCXX_HAVE__FMODF) && ! defined (_GLIBCXX_HAVE_FMODF)
+# define _GLIBCXX_HAVE_FMODF 1
+# define fmodf _fmodf
+#endif
+
+#if defined (_GLIBCXX_HAVE__FMODL) && ! defined (_GLIBCXX_HAVE_FMODL)
+# define _GLIBCXX_HAVE_FMODL 1
+# define fmodl _fmodl
+#endif
+
+#if defined (_GLIBCXX_HAVE__FPCLASS) && ! defined (_GLIBCXX_HAVE_FPCLASS)
+# define _GLIBCXX_HAVE_FPCLASS 1
+# define fpclass _fpclass
+#endif
+
+#if defined (_GLIBCXX_HAVE__FREXPF) && ! defined (_GLIBCXX_HAVE_FREXPF)
+# define _GLIBCXX_HAVE_FREXPF 1
+# define frexpf _frexpf
+#endif
+
+#if defined (_GLIBCXX_HAVE__FREXPL) && ! defined (_GLIBCXX_HAVE_FREXPL)
+# define _GLIBCXX_HAVE_FREXPL 1
+# define frexpl _frexpl
+#endif
+
+#if defined (_GLIBCXX_HAVE__HYPOT) && ! defined (_GLIBCXX_HAVE_HYPOT)
+# define _GLIBCXX_HAVE_HYPOT 1
+# define hypot _hypot
+#endif
+
+#if defined (_GLIBCXX_HAVE__HYPOTF) && ! defined (_GLIBCXX_HAVE_HYPOTF)
+# define _GLIBCXX_HAVE_HYPOTF 1
+# define hypotf _hypotf
+#endif
+
+#if defined (_GLIBCXX_HAVE__HYPOTL) && ! defined (_GLIBCXX_HAVE_HYPOTL)
+# define _GLIBCXX_HAVE_HYPOTL 1
+# define hypotl _hypotl
+#endif
+
+#if defined (_GLIBCXX_HAVE__ISINF) && ! defined (_GLIBCXX_HAVE_ISINF)
+# define _GLIBCXX_HAVE_ISINF 1
+# define isinf _isinf
+#endif
+
+#if defined (_GLIBCXX_HAVE__ISINFF) && ! defined (_GLIBCXX_HAVE_ISINFF)
+# define _GLIBCXX_HAVE_ISINFF 1
+# define isinff _isinff
+#endif
+
+#if defined (_GLIBCXX_HAVE__ISINFL) && ! defined (_GLIBCXX_HAVE_ISINFL)
+# define _GLIBCXX_HAVE_ISINFL 1
+# define isinfl _isinfl
+#endif
+
+#if defined (_GLIBCXX_HAVE__ISNAN) && ! defined (_GLIBCXX_HAVE_ISNAN)
+# define _GLIBCXX_HAVE_ISNAN 1
+# define isnan _isnan
+#endif
+
+#if defined (_GLIBCXX_HAVE__ISNANF) && ! defined (_GLIBCXX_HAVE_ISNANF)
+# define _GLIBCXX_HAVE_ISNANF 1
+# define isnanf _isnanf
+#endif
+
+#if defined (_GLIBCXX_HAVE__ISNANL) && ! defined (_GLIBCXX_HAVE_ISNANL)
+# define _GLIBCXX_HAVE_ISNANL 1
+# define isnanl _isnanl
+#endif
+
+#if defined (_GLIBCXX_HAVE__LDEXPF) && ! defined (_GLIBCXX_HAVE_LDEXPF)
+# define _GLIBCXX_HAVE_LDEXPF 1
+# define ldexpf _ldexpf
+#endif
+
+#if defined (_GLIBCXX_HAVE__LDEXPL) && ! defined (_GLIBCXX_HAVE_LDEXPL)
+# define _GLIBCXX_HAVE_LDEXPL 1
+# define ldexpl _ldexpl
+#endif
+
+#if defined (_GLIBCXX_HAVE__LOG10F) && ! defined (_GLIBCXX_HAVE_LOG10F)
+# define _GLIBCXX_HAVE_LOG10F 1
+# define log10f _log10f
+#endif
+
+#if defined (_GLIBCXX_HAVE__LOG10L) && ! defined (_GLIBCXX_HAVE_LOG10L)
+# define _GLIBCXX_HAVE_LOG10L 1
+# define log10l _log10l
+#endif
+
+#if defined (_GLIBCXX_HAVE__LOGF) && ! defined (_GLIBCXX_HAVE_LOGF)
+# define _GLIBCXX_HAVE_LOGF 1
+# define logf _logf
+#endif
+
+#if defined (_GLIBCXX_HAVE__LOGL) && ! defined (_GLIBCXX_HAVE_LOGL)
+# define _GLIBCXX_HAVE_LOGL 1
+# define logl _logl
+#endif
+
+#if defined (_GLIBCXX_HAVE__MODF) && ! defined (_GLIBCXX_HAVE_MODF)
+# define _GLIBCXX_HAVE_MODF 1
+# define modf _modf
+#endif
+
+#if defined (_GLIBCXX_HAVE__MODFF) && ! defined (_GLIBCXX_HAVE_MODFF)
+# define _GLIBCXX_HAVE_MODFF 1
+# define modff _modff
+#endif
+
+#if defined (_GLIBCXX_HAVE__MODFL) && ! defined (_GLIBCXX_HAVE_MODFL)
+# define _GLIBCXX_HAVE_MODFL 1
+# define modfl _modfl
+#endif
+
+#if defined (_GLIBCXX_HAVE__POWF) && ! defined (_GLIBCXX_HAVE_POWF)
+# define _GLIBCXX_HAVE_POWF 1
+# define powf _powf
+#endif
+
+#if defined (_GLIBCXX_HAVE__POWL) && ! defined (_GLIBCXX_HAVE_POWL)
+# define _GLIBCXX_HAVE_POWL 1
+# define powl _powl
+#endif
+
+#if defined (_GLIBCXX_HAVE__QFPCLASS) && ! defined (_GLIBCXX_HAVE_QFPCLASS)
+# define _GLIBCXX_HAVE_QFPCLASS 1
+# define qfpclass _qfpclass
+#endif
+
+#if defined (_GLIBCXX_HAVE__SINCOS) && ! defined (_GLIBCXX_HAVE_SINCOS)
+# define _GLIBCXX_HAVE_SINCOS 1
+# define sincos _sincos
+#endif
+
+#if defined (_GLIBCXX_HAVE__SINCOSF) && ! defined (_GLIBCXX_HAVE_SINCOSF)
+# define _GLIBCXX_HAVE_SINCOSF 1
+# define sincosf _sincosf
+#endif
+
+#if defined (_GLIBCXX_HAVE__SINCOSL) && ! defined (_GLIBCXX_HAVE_SINCOSL)
+# define _GLIBCXX_HAVE_SINCOSL 1
+# define sincosl _sincosl
+#endif
+
+#if defined (_GLIBCXX_HAVE__SINF) && ! defined (_GLIBCXX_HAVE_SINF)
+# define _GLIBCXX_HAVE_SINF 1
+# define sinf _sinf
+#endif
+
+#if defined (_GLIBCXX_HAVE__SINHF) && ! defined (_GLIBCXX_HAVE_SINHF)
+# define _GLIBCXX_HAVE_SINHF 1
+# define sinhf _sinhf
+#endif
+
+#if defined (_GLIBCXX_HAVE__SINHL) && ! defined (_GLIBCXX_HAVE_SINHL)
+# define _GLIBCXX_HAVE_SINHL 1
+# define sinhl _sinhl
+#endif
+
+#if defined (_GLIBCXX_HAVE__SINL) && ! defined (_GLIBCXX_HAVE_SINL)
+# define _GLIBCXX_HAVE_SINL 1
+# define sinl _sinl
+#endif
+
+#if defined (_GLIBCXX_HAVE__SQRTF) && ! defined (_GLIBCXX_HAVE_SQRTF)
+# define _GLIBCXX_HAVE_SQRTF 1
+# define sqrtf _sqrtf
+#endif
+
+#if defined (_GLIBCXX_HAVE__SQRTL) && ! defined (_GLIBCXX_HAVE_SQRTL)
+# define _GLIBCXX_HAVE_SQRTL 1
+# define sqrtl _sqrtl
+#endif
+
+#if defined (_GLIBCXX_HAVE__STRTOF) && ! defined (_GLIBCXX_HAVE_STRTOF)
+# define _GLIBCXX_HAVE_STRTOF 1
+# define strtof _strtof
+#endif
+
+#if defined (_GLIBCXX_HAVE__STRTOLD) && ! defined (_GLIBCXX_HAVE_STRTOLD)
+# define _GLIBCXX_HAVE_STRTOLD 1
+# define strtold _strtold
+#endif
+
+#if defined (_GLIBCXX_HAVE__TANF) && ! defined (_GLIBCXX_HAVE_TANF)
+# define _GLIBCXX_HAVE_TANF 1
+# define tanf _tanf
+#endif
+
+#if defined (_GLIBCXX_HAVE__TANHF) && ! defined (_GLIBCXX_HAVE_TANHF)
+# define _GLIBCXX_HAVE_TANHF 1
+# define tanhf _tanhf
+#endif
+
+#if defined (_GLIBCXX_HAVE__TANHL) && ! defined (_GLIBCXX_HAVE_TANHL)
+# define _GLIBCXX_HAVE_TANHL 1
+# define tanhl _tanhl
+#endif
+
+#if defined (_GLIBCXX_HAVE__TANL) && ! defined (_GLIBCXX_HAVE_TANL)
+# define _GLIBCXX_HAVE_TANL 1
+# define tanl _tanl
+#endif
+
+#endif // _GLIBCXX_CXX_CONFIG_H
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@x86_64-unknown-linux-gnu@bits@c++config.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@x86_64-unknown-linux-gnu@bits@c++config.h.blob
new file mode 100644
index 0000000000000000000000000000000000000000..5d8c61b00b9153b68073902f9dd1a710794df39b
Binary files /dev/null and b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@x86_64-unknown-linux-gnu@bits@c++config.h.blob differ
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@x86_64-unknown-linux-gnu@bits@c++io.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@x86_64-unknown-linux-gnu@bits@c++io.h
new file mode 100644
index 0000000000000000000000000000000000000000..1a5e05a844a427c75c173e14b0f19954323f3feb
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@x86_64-unknown-linux-gnu@bits@c++io.h
@@ -0,0 +1,50 @@
+// Underlying io library details -*- C++ -*-
+
+// Copyright (C) 2000-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/c++io.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{ios}
+ */
+
+// c_io_stdio.h - Defines for using "C" stdio.h
+
+#ifndef _GLIBCXX_CXX_IO_H
+#define _GLIBCXX_CXX_IO_H 1
+
+#include <cstdio>
+#include <bits/gthr.h>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  typedef __gthread_mutex_t __c_lock;
+
+  // for basic_file.h
+  typedef FILE __c_file;
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@x86_64-unknown-linux-gnu@bits@c++io.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@x86_64-unknown-linux-gnu@bits@c++io.h.blob
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Binary files /dev/null and b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@x86_64-unknown-linux-gnu@bits@c++io.h.blob differ
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@x86_64-unknown-linux-gnu@bits@c++locale.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@x86_64-unknown-linux-gnu@bits@c++locale.h
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index 0000000000000000000000000000000000000000..526b62215e120b7c1e4317402d2eff1d03c2e876
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@x86_64-unknown-linux-gnu@bits@c++locale.h
@@ -0,0 +1,124 @@
+// Wrapper for underlying C-language localization -*- C++ -*-
+
+// Copyright (C) 2001-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/c++locale.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{locale}
+ */
+
+//
+// ISO C++ 14882: 22.8  Standard locale categories.
+//
+
+// Written by Benjamin Kosnik <bkoz@redhat.com>
+
+#ifndef _GLIBCXX_CXX_LOCALE_H
+#define _GLIBCXX_CXX_LOCALE_H 1
+
+#pragma GCC system_header
+
+#include <clocale>
+
+#define _GLIBCXX_C_LOCALE_GNU 1
+
+#define _GLIBCXX_NUM_CATEGORIES 6
+
+#if __GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ > 2)
+namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  extern "C" __typeof(uselocale) __uselocale;
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+#endif
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  typedef __locale_t		__c_locale;
+
+#if defined _GLIBCXX_LONG_DOUBLE_ALT128_COMPAT \
+  && defined __LONG_DOUBLE_IEEE128__
+namespace __gnu_cxx_ieee128 {
+#endif
+
+  // Convert numeric value of type double and long double to string and
+  // return length of string.  If vsnprintf is available use it, otherwise
+  // fall back to the unsafe vsprintf which, in general, can be dangerous
+  // and should be avoided.
+  inline int
+  __convert_from_v(const __c_locale& __cloc __attribute__ ((__unused__)),
+		   char* __out,
+		   const int __size __attribute__ ((__unused__)),
+		   const char* __fmt, ...)
+  {
+#if __GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ > 2)
+    __c_locale __old = __gnu_cxx::__uselocale(__cloc);
+#else
+    char* __old = std::setlocale(LC_NUMERIC, 0);
+    char* __sav = 0;
+    if (__builtin_strcmp(__old, "C"))
+      {
+	const size_t __len = __builtin_strlen(__old) + 1;
+	__sav = new char[__len];
+	__builtin_memcpy(__sav, __old, __len);
+	std::setlocale(LC_NUMERIC, "C");
+      }
+#endif
+
+    __builtin_va_list __args;
+    __builtin_va_start(__args, __fmt);
+
+#if _GLIBCXX_USE_C99_STDIO
+    const int __ret = __builtin_vsnprintf(__out, __size, __fmt, __args);
+#else
+    const int __ret = __builtin_vsprintf(__out, __fmt, __args);
+#endif
+
+    __builtin_va_end(__args);
+
+#if __GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ > 2)
+    __gnu_cxx::__uselocale(__old);
+#else
+    if (__sav)
+      {
+	std::setlocale(LC_NUMERIC, __sav);
+	delete [] __sav;
+      }
+#endif
+    return __ret;
+  }
+
+#if defined _GLIBCXX_LONG_DOUBLE_ALT128_COMPAT \
+  && defined __LONG_DOUBLE_IEEE128__
+} // namespace __gnu_cxx_ieee128
+#endif
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@x86_64-unknown-linux-gnu@bits@c++locale.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@x86_64-unknown-linux-gnu@bits@c++locale.h.blob
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@@ -0,0 +1,33 @@
+// Specific definitions for generic platforms  -*- C++ -*-
+
+// Copyright (C) 2005-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/cpu_defines.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{iosfwd}
+ */
+
+#ifndef _GLIBCXX_CPU_DEFINES
+#define _GLIBCXX_CPU_DEFINES 1
+
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@x86_64-unknown-linux-gnu@bits@cpu_defines.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@x86_64-unknown-linux-gnu@bits@cpu_defines.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@x86_64-unknown-linux-gnu@bits@ctype_base.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@x86_64-unknown-linux-gnu@bits@ctype_base.h
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@x86_64-unknown-linux-gnu@bits@ctype_base.h
@@ -0,0 +1,66 @@
+// Locale support -*- C++ -*-
+
+// Copyright (C) 1997-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/ctype_base.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{locale}
+ */
+
+//
+// ISO C++ 14882: 22.1  Locales
+//
+
+// Information as gleaned from /usr/include/ctype.h
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /// @brief  Base class for ctype.
+  struct ctype_base
+  {
+    // Non-standard typedefs.
+    typedef const int* 		__to_type;
+
+    // NB: Offsets into ctype<char>::_M_table force a particular size
+    // on the mask type. Because of this, we don't use an enum.
+    typedef unsigned short 	mask;
+    static const mask upper    	= _ISupper;
+    static const mask lower 	= _ISlower;
+    static const mask alpha 	= _ISalpha;
+    static const mask digit 	= _ISdigit;
+    static const mask xdigit 	= _ISxdigit;
+    static const mask space 	= _ISspace;
+    static const mask print 	= _ISprint;
+    static const mask graph 	= _ISalpha | _ISdigit | _ISpunct;
+    static const mask cntrl 	= _IScntrl;
+    static const mask punct 	= _ISpunct;
+    static const mask alnum 	= _ISalpha | _ISdigit;
+#if __cplusplus >= 201103L
+    static const mask blank	= _ISblank;
+#endif
+  };
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@x86_64-unknown-linux-gnu@bits@ctype_base.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@x86_64-unknown-linux-gnu@bits@ctype_base.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@x86_64-unknown-linux-gnu@bits@ctype_inline.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@x86_64-unknown-linux-gnu@bits@ctype_inline.h
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--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@x86_64-unknown-linux-gnu@bits@ctype_inline.h
@@ -0,0 +1,76 @@
+// Locale support -*- C++ -*-
+
+// Copyright (C) 2000-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/ctype_inline.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{locale}
+ */
+
+//
+// ISO C++ 14882: 22.1  Locales
+//
+
+// ctype bits to be inlined go here. Non-inlinable (ie virtual do_*)
+// functions go in ctype.cc
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  bool
+  ctype<char>::
+  is(mask __m, char __c) const
+  { return _M_table[static_cast<unsigned char>(__c)] & __m; }
+
+  const char*
+  ctype<char>::
+  is(const char* __low, const char* __high, mask* __vec) const
+  {
+    while (__low < __high)
+      *__vec++ = _M_table[static_cast<unsigned char>(*__low++)];
+    return __high;
+  }
+
+  const char*
+  ctype<char>::
+  scan_is(mask __m, const char* __low, const char* __high) const
+  {
+    while (__low < __high
+	   && !(_M_table[static_cast<unsigned char>(*__low)] & __m))
+      ++__low;
+    return __low;
+  }
+
+  const char*
+  ctype<char>::
+  scan_not(mask __m, const char* __low, const char* __high) const
+  {
+    while (__low < __high
+	   && (_M_table[static_cast<unsigned char>(*__low)] & __m) != 0)
+      ++__low;
+    return __low;
+  }
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@x86_64-unknown-linux-gnu@bits@ctype_inline.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@x86_64-unknown-linux-gnu@bits@ctype_inline.h.blob
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@@ -0,0 +1,178 @@
+// Specific definitions for generic platforms  -*- C++ -*-
+
+// Copyright (C) 2007-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/error_constants.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{system_error}
+ */
+
+#ifndef _GLIBCXX_ERROR_CONSTANTS
+#define _GLIBCXX_ERROR_CONSTANTS 1
+
+#include <bits/c++config.h>
+#include <cerrno>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  enum class errc
+    {
+      address_family_not_supported = 		EAFNOSUPPORT,
+      address_in_use = 				EADDRINUSE,
+      address_not_available = 			EADDRNOTAVAIL,
+      already_connected = 			EISCONN,
+      argument_list_too_long = 			E2BIG,
+      argument_out_of_domain = 			EDOM,
+      bad_address = 				EFAULT,
+      bad_file_descriptor = 			EBADF,
+
+#ifdef EBADMSG
+      bad_message = 				EBADMSG,
+#endif
+
+      broken_pipe = 				EPIPE,
+      connection_aborted = 			ECONNABORTED,
+      connection_already_in_progress = 		EALREADY,
+      connection_refused = 			ECONNREFUSED,
+      connection_reset = 			ECONNRESET,
+      cross_device_link = 			EXDEV,
+      destination_address_required = 		EDESTADDRREQ,
+      device_or_resource_busy = 		EBUSY,
+      directory_not_empty = 			ENOTEMPTY,
+      executable_format_error = 		ENOEXEC,
+      file_exists = 	       			EEXIST,
+      file_too_large = 				EFBIG,
+      filename_too_long = 			ENAMETOOLONG,
+      function_not_supported = 			ENOSYS,
+      host_unreachable = 			EHOSTUNREACH,
+
+#ifdef EIDRM
+      identifier_removed = 			EIDRM,
+#endif
+
+      illegal_byte_sequence = 			EILSEQ,
+      inappropriate_io_control_operation = 	ENOTTY,
+      interrupted = 				EINTR,
+      invalid_argument = 			EINVAL,
+      invalid_seek = 				ESPIPE,
+      io_error = 				EIO,
+      is_a_directory = 				EISDIR,
+      message_size = 				EMSGSIZE,
+      network_down = 				ENETDOWN,
+      network_reset = 				ENETRESET,
+      network_unreachable = 			ENETUNREACH,
+      no_buffer_space = 			ENOBUFS,
+      no_child_process = 			ECHILD,
+
+#ifdef ENOLINK
+      no_link = 				ENOLINK,
+#endif
+
+      no_lock_available = 			ENOLCK,
+
+#ifdef ENODATA
+      no_message_available = 			ENODATA,
+#endif
+
+      no_message = 				ENOMSG,
+      no_protocol_option = 			ENOPROTOOPT,
+      no_space_on_device = 			ENOSPC,
+
+#ifdef ENOSR
+      no_stream_resources = 			ENOSR,
+#endif
+
+      no_such_device_or_address = 		ENXIO,
+      no_such_device = 				ENODEV,
+      no_such_file_or_directory = 		ENOENT,
+      no_such_process = 			ESRCH,
+      not_a_directory = 			ENOTDIR,
+      not_a_socket = 				ENOTSOCK,
+
+#ifdef ENOSTR
+      not_a_stream = 				ENOSTR,
+#endif
+
+      not_connected = 				ENOTCONN,
+      not_enough_memory = 			ENOMEM,
+
+#ifdef ENOTSUP
+      not_supported = 				ENOTSUP,
+#endif
+
+#ifdef ECANCELED
+      operation_canceled = 			ECANCELED,
+#endif
+
+      operation_in_progress = 			EINPROGRESS,
+      operation_not_permitted = 		EPERM,
+      operation_not_supported = 		EOPNOTSUPP,
+      operation_would_block = 			EWOULDBLOCK,
+
+#ifdef EOWNERDEAD
+      owner_dead = 				EOWNERDEAD,
+#endif
+
+      permission_denied = 			EACCES,
+
+#ifdef EPROTO
+      protocol_error = 				EPROTO,
+#endif
+
+      protocol_not_supported = 			EPROTONOSUPPORT,
+      read_only_file_system = 			EROFS,
+      resource_deadlock_would_occur = 		EDEADLK,
+      resource_unavailable_try_again = 		EAGAIN,
+      result_out_of_range = 			ERANGE,
+
+#ifdef ENOTRECOVERABLE
+      state_not_recoverable = 			ENOTRECOVERABLE,
+#endif
+
+#ifdef ETIME
+      stream_timeout = 				ETIME,
+#endif
+
+#ifdef ETXTBSY
+      text_file_busy = 				ETXTBSY,
+#endif
+
+      timed_out = 				ETIMEDOUT,
+      too_many_files_open_in_system = 		ENFILE,
+      too_many_files_open = 			EMFILE,
+      too_many_links = 				EMLINK,
+      too_many_symbolic_link_levels = 		ELOOP,
+
+#ifdef EOVERFLOW
+      value_too_large = 			EOVERFLOW,
+#endif
+
+      wrong_protocol_type = 			EPROTOTYPE
+    };
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@x86_64-unknown-linux-gnu@bits@gthr-default.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@x86_64-unknown-linux-gnu@bits@gthr-default.h
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@x86_64-unknown-linux-gnu@bits@gthr-default.h
@@ -0,0 +1,890 @@
+/* Threads compatibility routines for libgcc2 and libobjc.  */
+/* Compile this one with gcc.  */
+/* Copyright (C) 1997-2022 Free Software Foundation, Inc.
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 3, or (at your option) any later
+version.
+
+GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+Under Section 7 of GPL version 3, you are granted additional
+permissions described in the GCC Runtime Library Exception, version
+3.1, as published by the Free Software Foundation.
+
+You should have received a copy of the GNU General Public License and
+a copy of the GCC Runtime Library Exception along with this program;
+see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+<http://www.gnu.org/licenses/>.  */
+
+#ifndef _GLIBCXX_GCC_GTHR_POSIX_H
+#define _GLIBCXX_GCC_GTHR_POSIX_H
+
+/* POSIX threads specific definitions.
+   Easy, since the interface is just one-to-one mapping.  */
+
+#define __GTHREADS 1
+#define __GTHREADS_CXX0X 1
+
+#include <pthread.h>
+
+#if ((defined(_LIBOBJC) || defined(_LIBOBJC_WEAK)) \
+     || !defined(_GTHREAD_USE_MUTEX_TIMEDLOCK))
+# include <unistd.h>
+# if defined(_POSIX_TIMEOUTS) && _POSIX_TIMEOUTS >= 0
+#  define _GTHREAD_USE_MUTEX_TIMEDLOCK 1
+# else
+#  define _GTHREAD_USE_MUTEX_TIMEDLOCK 0
+# endif
+#endif
+
+typedef pthread_t __gthread_t;
+typedef pthread_key_t __gthread_key_t;
+typedef pthread_once_t __gthread_once_t;
+typedef pthread_mutex_t __gthread_mutex_t;
+typedef pthread_mutex_t __gthread_recursive_mutex_t;
+typedef pthread_cond_t __gthread_cond_t;
+typedef struct timespec __gthread_time_t;
+
+/* POSIX like conditional variables are supported.  Please look at comments
+   in gthr.h for details. */
+#define __GTHREAD_HAS_COND	1
+
+#define __GTHREAD_MUTEX_INIT PTHREAD_MUTEX_INITIALIZER
+#define __GTHREAD_MUTEX_INIT_FUNCTION __gthread_mutex_init_function
+#define __GTHREAD_ONCE_INIT PTHREAD_ONCE_INIT
+#if defined(PTHREAD_RECURSIVE_MUTEX_INITIALIZER)
+#define __GTHREAD_RECURSIVE_MUTEX_INIT PTHREAD_RECURSIVE_MUTEX_INITIALIZER
+#elif defined(PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP)
+#define __GTHREAD_RECURSIVE_MUTEX_INIT PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP
+#else
+#define __GTHREAD_RECURSIVE_MUTEX_INIT_FUNCTION __gthread_recursive_mutex_init_function
+#endif
+#define __GTHREAD_COND_INIT PTHREAD_COND_INITIALIZER
+#define __GTHREAD_TIME_INIT {0,0}
+
+#ifdef _GTHREAD_USE_MUTEX_INIT_FUNC
+# undef __GTHREAD_MUTEX_INIT
+#endif
+#ifdef _GTHREAD_USE_RECURSIVE_MUTEX_INIT_FUNC
+# undef __GTHREAD_RECURSIVE_MUTEX_INIT
+# undef __GTHREAD_RECURSIVE_MUTEX_INIT_FUNCTION
+# define __GTHREAD_RECURSIVE_MUTEX_INIT_FUNCTION __gthread_recursive_mutex_init_function
+#endif
+#ifdef _GTHREAD_USE_COND_INIT_FUNC
+# undef __GTHREAD_COND_INIT
+# define __GTHREAD_COND_INIT_FUNCTION __gthread_cond_init_function
+#endif
+
+#if __GXX_WEAK__ && _GLIBCXX_GTHREAD_USE_WEAK
+# ifndef __gthrw_pragma
+#  define __gthrw_pragma(pragma)
+# endif
+# define __gthrw2(name,name2,type) \
+  static __typeof(type) name \
+    __attribute__ ((__weakref__(#name2), __copy__ (type))); \
+  __gthrw_pragma(weak type)
+# define __gthrw_(name) __gthrw_ ## name
+#else
+# define __gthrw2(name,name2,type)
+# define __gthrw_(name) name
+#endif
+
+/* Typically, __gthrw_foo is a weak reference to symbol foo.  */
+#define __gthrw(name) __gthrw2(__gthrw_ ## name,name,name)
+
+__gthrw(pthread_once)
+__gthrw(pthread_getspecific)
+__gthrw(pthread_setspecific)
+
+__gthrw(pthread_create)
+__gthrw(pthread_join)
+__gthrw(pthread_equal)
+__gthrw(pthread_self)
+__gthrw(pthread_detach)
+#ifndef __BIONIC__
+__gthrw(pthread_cancel)
+#endif
+__gthrw(sched_yield)
+
+__gthrw(pthread_mutex_lock)
+__gthrw(pthread_mutex_trylock)
+#if _GTHREAD_USE_MUTEX_TIMEDLOCK
+__gthrw(pthread_mutex_timedlock)
+#endif
+__gthrw(pthread_mutex_unlock)
+__gthrw(pthread_mutex_init)
+__gthrw(pthread_mutex_destroy)
+
+__gthrw(pthread_cond_init)
+__gthrw(pthread_cond_broadcast)
+__gthrw(pthread_cond_signal)
+__gthrw(pthread_cond_wait)
+__gthrw(pthread_cond_timedwait)
+__gthrw(pthread_cond_destroy)
+
+__gthrw(pthread_key_create)
+__gthrw(pthread_key_delete)
+__gthrw(pthread_mutexattr_init)
+__gthrw(pthread_mutexattr_settype)
+__gthrw(pthread_mutexattr_destroy)
+
+
+#if defined(_LIBOBJC) || defined(_LIBOBJC_WEAK)
+/* Objective-C.  */
+__gthrw(pthread_exit)
+#ifdef _POSIX_PRIORITY_SCHEDULING
+#ifdef _POSIX_THREAD_PRIORITY_SCHEDULING
+__gthrw(sched_get_priority_max)
+__gthrw(sched_get_priority_min)
+#endif /* _POSIX_THREAD_PRIORITY_SCHEDULING */
+#endif /* _POSIX_PRIORITY_SCHEDULING */
+__gthrw(pthread_attr_destroy)
+__gthrw(pthread_attr_init)
+__gthrw(pthread_attr_setdetachstate)
+#ifdef _POSIX_THREAD_PRIORITY_SCHEDULING
+__gthrw(pthread_getschedparam)
+__gthrw(pthread_setschedparam)
+#endif /* _POSIX_THREAD_PRIORITY_SCHEDULING */
+#endif /* _LIBOBJC || _LIBOBJC_WEAK */
+
+#if __GXX_WEAK__ && _GLIBCXX_GTHREAD_USE_WEAK
+
+/* On Solaris 2.6 up to 9, the libc exposes a POSIX threads interface even if
+   -pthreads is not specified.  The functions are dummies and most return an
+   error value.  However pthread_once returns 0 without invoking the routine
+   it is passed so we cannot pretend that the interface is active if -pthreads
+   is not specified.  On Solaris 2.5.1, the interface is not exposed at all so
+   we need to play the usual game with weak symbols.  On Solaris 10 and up, a
+   working interface is always exposed.  On FreeBSD 6 and later, libc also
+   exposes a dummy POSIX threads interface, similar to what Solaris 2.6 up
+   to 9 does.  FreeBSD >= 700014 even provides a pthread_cancel stub in libc,
+   which means the alternate __gthread_active_p below cannot be used there.  */
+
+#if defined(__FreeBSD__) || (defined(__sun) && defined(__svr4__))
+
+static volatile int __gthread_active = -1;
+
+static void
+__gthread_trigger (void)
+{
+  __gthread_active = 1;
+}
+
+static inline int
+__gthread_active_p (void)
+{
+  static pthread_mutex_t __gthread_active_mutex = PTHREAD_MUTEX_INITIALIZER;
+  static pthread_once_t __gthread_active_once = PTHREAD_ONCE_INIT;
+
+  /* Avoid reading __gthread_active twice on the main code path.  */
+  int __gthread_active_latest_value = __gthread_active;
+
+  /* This test is not protected to avoid taking a lock on the main code
+     path so every update of __gthread_active in a threaded program must
+     be atomic with regard to the result of the test.  */
+  if (__builtin_expect (__gthread_active_latest_value < 0, 0))
+    {
+      if (__gthrw_(pthread_once))
+	{
+	  /* If this really is a threaded program, then we must ensure that
+	     __gthread_active has been set to 1 before exiting this block.  */
+	  __gthrw_(pthread_mutex_lock) (&__gthread_active_mutex);
+	  __gthrw_(pthread_once) (&__gthread_active_once, __gthread_trigger);
+	  __gthrw_(pthread_mutex_unlock) (&__gthread_active_mutex);
+	}
+
+      /* Make sure we'll never enter this block again.  */
+      if (__gthread_active < 0)
+	__gthread_active = 0;
+
+      __gthread_active_latest_value = __gthread_active;
+    }
+
+  return __gthread_active_latest_value != 0;
+}
+
+#else /* neither FreeBSD nor Solaris */
+
+/* For a program to be multi-threaded the only thing that it certainly must
+   be using is pthread_create.  However, there may be other libraries that
+   intercept pthread_create with their own definitions to wrap pthreads
+   functionality for some purpose.  In those cases, pthread_create being
+   defined might not necessarily mean that libpthread is actually linked
+   in.
+
+   For the GNU C library, we can use a known internal name.  This is always
+   available in the ABI, but no other library would define it.  That is
+   ideal, since any public pthread function might be intercepted just as
+   pthread_create might be.  __pthread_key_create is an "internal"
+   implementation symbol, but it is part of the public exported ABI.  Also,
+   it's among the symbols that the static libpthread.a always links in
+   whenever pthread_create is used, so there is no danger of a false
+   negative result in any statically-linked, multi-threaded program.
+
+   For others, we choose pthread_cancel as a function that seems unlikely
+   to be redefined by an interceptor library.  The bionic (Android) C
+   library does not provide pthread_cancel, so we do use pthread_create
+   there (and interceptor libraries lose).  */
+
+#ifdef __GLIBC__
+__gthrw2(__gthrw_(__pthread_key_create),
+	 __pthread_key_create,
+	 pthread_key_create)
+# define GTHR_ACTIVE_PROXY	__gthrw_(__pthread_key_create)
+#elif defined (__BIONIC__)
+# define GTHR_ACTIVE_PROXY	__gthrw_(pthread_create)
+#else
+# define GTHR_ACTIVE_PROXY	__gthrw_(pthread_cancel)
+#endif
+
+static inline int
+__gthread_active_p (void)
+{
+  static void *const __gthread_active_ptr
+    = __extension__ (void *) &GTHR_ACTIVE_PROXY;
+  return __gthread_active_ptr != 0;
+}
+
+#endif /* FreeBSD or Solaris */
+
+#else /* not __GXX_WEAK__ */
+
+/* Similar to Solaris, HP-UX 11 for PA-RISC provides stubs for pthread
+   calls in shared flavors of the HP-UX C library.  Most of the stubs
+   have no functionality.  The details are described in the "libc cumulative
+   patch" for each subversion of HP-UX 11.  There are two special interfaces
+   provided for checking whether an application is linked to a shared pthread
+   library or not.  However, these interfaces aren't available in early
+   libpthread libraries.  We also need a test that works for archive
+   libraries.  We can't use pthread_once as some libc versions call the
+   init function.  We also can't use pthread_create or pthread_attr_init
+   as these create a thread and thereby prevent changing the default stack
+   size.  The function pthread_default_stacksize_np is available in both
+   the archive and shared versions of libpthread.   It can be used to
+   determine the default pthread stack size.  There is a stub in some
+   shared libc versions which returns a zero size if pthreads are not
+   active.  We provide an equivalent stub to handle cases where libc
+   doesn't provide one.  */
+
+#if defined(__hppa__) && defined(__hpux__)
+
+static volatile int __gthread_active = -1;
+
+static inline int
+__gthread_active_p (void)
+{
+  /* Avoid reading __gthread_active twice on the main code path.  */
+  int __gthread_active_latest_value = __gthread_active;
+  size_t __s;
+
+  if (__builtin_expect (__gthread_active_latest_value < 0, 0))
+    {
+      pthread_default_stacksize_np (0, &__s);
+      __gthread_active = __s ? 1 : 0;
+      __gthread_active_latest_value = __gthread_active;
+    }
+
+  return __gthread_active_latest_value != 0;
+}
+
+#else /* not hppa-hpux */
+
+static inline int
+__gthread_active_p (void)
+{
+  return 1;
+}
+
+#endif /* hppa-hpux */
+
+#endif /* __GXX_WEAK__ */
+
+#ifdef _LIBOBJC
+
+/* This is the config.h file in libobjc/ */
+#include <config.h>
+
+#ifdef HAVE_SCHED_H
+# include <sched.h>
+#endif
+
+/* Key structure for maintaining thread specific storage */
+static pthread_key_t _objc_thread_storage;
+static pthread_attr_t _objc_thread_attribs;
+
+/* Thread local storage for a single thread */
+static void *thread_local_storage = NULL;
+
+/* Backend initialization functions */
+
+/* Initialize the threads subsystem.  */
+static inline int
+__gthread_objc_init_thread_system (void)
+{
+  if (__gthread_active_p ())
+    {
+      /* Initialize the thread storage key.  */
+      if (__gthrw_(pthread_key_create) (&_objc_thread_storage, NULL) == 0)
+	{
+	  /* The normal default detach state for threads is
+	   * PTHREAD_CREATE_JOINABLE which causes threads to not die
+	   * when you think they should.  */
+	  if (__gthrw_(pthread_attr_init) (&_objc_thread_attribs) == 0
+	      && __gthrw_(pthread_attr_setdetachstate) (&_objc_thread_attribs,
+					      PTHREAD_CREATE_DETACHED) == 0)
+	    return 0;
+	}
+    }
+
+  return -1;
+}
+
+/* Close the threads subsystem.  */
+static inline int
+__gthread_objc_close_thread_system (void)
+{
+  if (__gthread_active_p ()
+      && __gthrw_(pthread_key_delete) (_objc_thread_storage) == 0
+      && __gthrw_(pthread_attr_destroy) (&_objc_thread_attribs) == 0)
+    return 0;
+
+  return -1;
+}
+
+/* Backend thread functions */
+
+/* Create a new thread of execution.  */
+static inline objc_thread_t
+__gthread_objc_thread_detach (void (*func)(void *), void *arg)
+{
+  objc_thread_t thread_id;
+  pthread_t new_thread_handle;
+
+  if (!__gthread_active_p ())
+    return NULL;
+
+  if (!(__gthrw_(pthread_create) (&new_thread_handle, &_objc_thread_attribs,
+				  (void *) func, arg)))
+    thread_id = (objc_thread_t) new_thread_handle;
+  else
+    thread_id = NULL;
+
+  return thread_id;
+}
+
+/* Set the current thread's priority.  */
+static inline int
+__gthread_objc_thread_set_priority (int priority)
+{
+  if (!__gthread_active_p ())
+    return -1;
+  else
+    {
+#ifdef _POSIX_PRIORITY_SCHEDULING
+#ifdef _POSIX_THREAD_PRIORITY_SCHEDULING
+      pthread_t thread_id = __gthrw_(pthread_self) ();
+      int policy;
+      struct sched_param params;
+      int priority_min, priority_max;
+
+      if (__gthrw_(pthread_getschedparam) (thread_id, &policy, &params) == 0)
+	{
+	  if ((priority_max = __gthrw_(sched_get_priority_max) (policy)) == -1)
+	    return -1;
+
+	  if ((priority_min = __gthrw_(sched_get_priority_min) (policy)) == -1)
+	    return -1;
+
+	  if (priority > priority_max)
+	    priority = priority_max;
+	  else if (priority < priority_min)
+	    priority = priority_min;
+	  params.sched_priority = priority;
+
+	  /*
+	   * The solaris 7 and several other man pages incorrectly state that
+	   * this should be a pointer to policy but pthread.h is universally
+	   * at odds with this.
+	   */
+	  if (__gthrw_(pthread_setschedparam) (thread_id, policy, &params) == 0)
+	    return 0;
+	}
+#endif /* _POSIX_THREAD_PRIORITY_SCHEDULING */
+#endif /* _POSIX_PRIORITY_SCHEDULING */
+      return -1;
+    }
+}
+
+/* Return the current thread's priority.  */
+static inline int
+__gthread_objc_thread_get_priority (void)
+{
+#ifdef _POSIX_PRIORITY_SCHEDULING
+#ifdef _POSIX_THREAD_PRIORITY_SCHEDULING
+  if (__gthread_active_p ())
+    {
+      int policy;
+      struct sched_param params;
+
+      if (__gthrw_(pthread_getschedparam) (__gthrw_(pthread_self) (), &policy, &params) == 0)
+	return params.sched_priority;
+      else
+	return -1;
+    }
+  else
+#endif /* _POSIX_THREAD_PRIORITY_SCHEDULING */
+#endif /* _POSIX_PRIORITY_SCHEDULING */
+    return OBJC_THREAD_INTERACTIVE_PRIORITY;
+}
+
+/* Yield our process time to another thread.  */
+static inline void
+__gthread_objc_thread_yield (void)
+{
+  if (__gthread_active_p ())
+    __gthrw_(sched_yield) ();
+}
+
+/* Terminate the current thread.  */
+static inline int
+__gthread_objc_thread_exit (void)
+{
+  if (__gthread_active_p ())
+    /* exit the thread */
+    __gthrw_(pthread_exit) (&__objc_thread_exit_status);
+
+  /* Failed if we reached here */
+  return -1;
+}
+
+/* Returns an integer value which uniquely describes a thread.  */
+static inline objc_thread_t
+__gthread_objc_thread_id (void)
+{
+  if (__gthread_active_p ())
+    return (objc_thread_t) __gthrw_(pthread_self) ();
+  else
+    return (objc_thread_t) 1;
+}
+
+/* Sets the thread's local storage pointer.  */
+static inline int
+__gthread_objc_thread_set_data (void *value)
+{
+  if (__gthread_active_p ())
+    return __gthrw_(pthread_setspecific) (_objc_thread_storage, value);
+  else
+    {
+      thread_local_storage = value;
+      return 0;
+    }
+}
+
+/* Returns the thread's local storage pointer.  */
+static inline void *
+__gthread_objc_thread_get_data (void)
+{
+  if (__gthread_active_p ())
+    return __gthrw_(pthread_getspecific) (_objc_thread_storage);
+  else
+    return thread_local_storage;
+}
+
+/* Backend mutex functions */
+
+/* Allocate a mutex.  */
+static inline int
+__gthread_objc_mutex_allocate (objc_mutex_t mutex)
+{
+  if (__gthread_active_p ())
+    {
+      mutex->backend = objc_malloc (sizeof (pthread_mutex_t));
+
+      if (__gthrw_(pthread_mutex_init) ((pthread_mutex_t *) mutex->backend, NULL))
+	{
+	  objc_free (mutex->backend);
+	  mutex->backend = NULL;
+	  return -1;
+	}
+    }
+
+  return 0;
+}
+
+/* Deallocate a mutex.  */
+static inline int
+__gthread_objc_mutex_deallocate (objc_mutex_t mutex)
+{
+  if (__gthread_active_p ())
+    {
+      int count;
+
+      /*
+       * Posix Threads specifically require that the thread be unlocked
+       * for __gthrw_(pthread_mutex_destroy) to work.
+       */
+
+      do
+	{
+	  count = __gthrw_(pthread_mutex_unlock) ((pthread_mutex_t *) mutex->backend);
+	  if (count < 0)
+	    return -1;
+	}
+      while (count);
+
+      if (__gthrw_(pthread_mutex_destroy) ((pthread_mutex_t *) mutex->backend))
+	return -1;
+
+      objc_free (mutex->backend);
+      mutex->backend = NULL;
+    }
+  return 0;
+}
+
+/* Grab a lock on a mutex.  */
+static inline int
+__gthread_objc_mutex_lock (objc_mutex_t mutex)
+{
+  if (__gthread_active_p ()
+      && __gthrw_(pthread_mutex_lock) ((pthread_mutex_t *) mutex->backend) != 0)
+    {
+      return -1;
+    }
+
+  return 0;
+}
+
+/* Try to grab a lock on a mutex.  */
+static inline int
+__gthread_objc_mutex_trylock (objc_mutex_t mutex)
+{
+  if (__gthread_active_p ()
+      && __gthrw_(pthread_mutex_trylock) ((pthread_mutex_t *) mutex->backend) != 0)
+    {
+      return -1;
+    }
+
+  return 0;
+}
+
+/* Unlock the mutex */
+static inline int
+__gthread_objc_mutex_unlock (objc_mutex_t mutex)
+{
+  if (__gthread_active_p ()
+      && __gthrw_(pthread_mutex_unlock) ((pthread_mutex_t *) mutex->backend) != 0)
+    {
+      return -1;
+    }
+
+  return 0;
+}
+
+/* Backend condition mutex functions */
+
+/* Allocate a condition.  */
+static inline int
+__gthread_objc_condition_allocate (objc_condition_t condition)
+{
+  if (__gthread_active_p ())
+    {
+      condition->backend = objc_malloc (sizeof (pthread_cond_t));
+
+      if (__gthrw_(pthread_cond_init) ((pthread_cond_t *) condition->backend, NULL))
+	{
+	  objc_free (condition->backend);
+	  condition->backend = NULL;
+	  return -1;
+	}
+    }
+
+  return 0;
+}
+
+/* Deallocate a condition.  */
+static inline int
+__gthread_objc_condition_deallocate (objc_condition_t condition)
+{
+  if (__gthread_active_p ())
+    {
+      if (__gthrw_(pthread_cond_destroy) ((pthread_cond_t *) condition->backend))
+	return -1;
+
+      objc_free (condition->backend);
+      condition->backend = NULL;
+    }
+  return 0;
+}
+
+/* Wait on the condition */
+static inline int
+__gthread_objc_condition_wait (objc_condition_t condition, objc_mutex_t mutex)
+{
+  if (__gthread_active_p ())
+    return __gthrw_(pthread_cond_wait) ((pthread_cond_t *) condition->backend,
+			      (pthread_mutex_t *) mutex->backend);
+  else
+    return 0;
+}
+
+/* Wake up all threads waiting on this condition.  */
+static inline int
+__gthread_objc_condition_broadcast (objc_condition_t condition)
+{
+  if (__gthread_active_p ())
+    return __gthrw_(pthread_cond_broadcast) ((pthread_cond_t *) condition->backend);
+  else
+    return 0;
+}
+
+/* Wake up one thread waiting on this condition.  */
+static inline int
+__gthread_objc_condition_signal (objc_condition_t condition)
+{
+  if (__gthread_active_p ())
+    return __gthrw_(pthread_cond_signal) ((pthread_cond_t *) condition->backend);
+  else
+    return 0;
+}
+
+#else /* _LIBOBJC */
+
+static inline int
+__gthread_create (__gthread_t *__threadid, void *(*__func) (void*),
+		  void *__args)
+{
+  return __gthrw_(pthread_create) (__threadid, NULL, __func, __args);
+}
+
+static inline int
+__gthread_join (__gthread_t __threadid, void **__value_ptr)
+{
+  return __gthrw_(pthread_join) (__threadid, __value_ptr);
+}
+
+static inline int
+__gthread_detach (__gthread_t __threadid)
+{
+  return __gthrw_(pthread_detach) (__threadid);
+}
+
+static inline int
+__gthread_equal (__gthread_t __t1, __gthread_t __t2)
+{
+  return __gthrw_(pthread_equal) (__t1, __t2);
+}
+
+static inline __gthread_t
+__gthread_self (void)
+{
+  return __gthrw_(pthread_self) ();
+}
+
+static inline int
+__gthread_yield (void)
+{
+  return __gthrw_(sched_yield) ();
+}
+
+static inline int
+__gthread_once (__gthread_once_t *__once, void (*__func) (void))
+{
+  if (__gthread_active_p ())
+    return __gthrw_(pthread_once) (__once, __func);
+  else
+    return -1;
+}
+
+static inline int
+__gthread_key_create (__gthread_key_t *__key, void (*__dtor) (void *))
+{
+  return __gthrw_(pthread_key_create) (__key, __dtor);
+}
+
+static inline int
+__gthread_key_delete (__gthread_key_t __key)
+{
+  return __gthrw_(pthread_key_delete) (__key);
+}
+
+static inline void *
+__gthread_getspecific (__gthread_key_t __key)
+{
+  return __gthrw_(pthread_getspecific) (__key);
+}
+
+static inline int
+__gthread_setspecific (__gthread_key_t __key, const void *__ptr)
+{
+  return __gthrw_(pthread_setspecific) (__key, __ptr);
+}
+
+static inline void
+__gthread_mutex_init_function (__gthread_mutex_t *__mutex)
+{
+  if (__gthread_active_p ())
+    __gthrw_(pthread_mutex_init) (__mutex, NULL);
+}
+
+static inline int
+__gthread_mutex_destroy (__gthread_mutex_t *__mutex)
+{
+  if (__gthread_active_p ())
+    return __gthrw_(pthread_mutex_destroy) (__mutex);
+  else
+    return 0;
+}
+
+static inline int
+__gthread_mutex_lock (__gthread_mutex_t *__mutex)
+{
+  if (__gthread_active_p ())
+    return __gthrw_(pthread_mutex_lock) (__mutex);
+  else
+    return 0;
+}
+
+static inline int
+__gthread_mutex_trylock (__gthread_mutex_t *__mutex)
+{
+  if (__gthread_active_p ())
+    return __gthrw_(pthread_mutex_trylock) (__mutex);
+  else
+    return 0;
+}
+
+#if _GTHREAD_USE_MUTEX_TIMEDLOCK
+static inline int
+__gthread_mutex_timedlock (__gthread_mutex_t *__mutex,
+			   const __gthread_time_t *__abs_timeout)
+{
+  if (__gthread_active_p ())
+    return __gthrw_(pthread_mutex_timedlock) (__mutex, __abs_timeout);
+  else
+    return 0;
+}
+#endif
+
+static inline int
+__gthread_mutex_unlock (__gthread_mutex_t *__mutex)
+{
+  if (__gthread_active_p ())
+    return __gthrw_(pthread_mutex_unlock) (__mutex);
+  else
+    return 0;
+}
+
+#if !defined( PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP) \
+  || defined(_GTHREAD_USE_RECURSIVE_MUTEX_INIT_FUNC)
+static inline int
+__gthread_recursive_mutex_init_function (__gthread_recursive_mutex_t *__mutex)
+{
+  if (__gthread_active_p ())
+    {
+      pthread_mutexattr_t __attr;
+      int __r;
+
+      __r = __gthrw_(pthread_mutexattr_init) (&__attr);
+      if (!__r)
+	__r = __gthrw_(pthread_mutexattr_settype) (&__attr,
+						   PTHREAD_MUTEX_RECURSIVE);
+      if (!__r)
+	__r = __gthrw_(pthread_mutex_init) (__mutex, &__attr);
+      if (!__r)
+	__r = __gthrw_(pthread_mutexattr_destroy) (&__attr);
+      return __r;
+    }
+  return 0;
+}
+#endif
+
+static inline int
+__gthread_recursive_mutex_lock (__gthread_recursive_mutex_t *__mutex)
+{
+  return __gthread_mutex_lock (__mutex);
+}
+
+static inline int
+__gthread_recursive_mutex_trylock (__gthread_recursive_mutex_t *__mutex)
+{
+  return __gthread_mutex_trylock (__mutex);
+}
+
+#if _GTHREAD_USE_MUTEX_TIMEDLOCK
+static inline int
+__gthread_recursive_mutex_timedlock (__gthread_recursive_mutex_t *__mutex,
+				     const __gthread_time_t *__abs_timeout)
+{
+  return __gthread_mutex_timedlock (__mutex, __abs_timeout);
+}
+#endif
+
+static inline int
+__gthread_recursive_mutex_unlock (__gthread_recursive_mutex_t *__mutex)
+{
+  return __gthread_mutex_unlock (__mutex);
+}
+
+static inline int
+__gthread_recursive_mutex_destroy (__gthread_recursive_mutex_t *__mutex)
+{
+  return __gthread_mutex_destroy (__mutex);
+}
+
+#ifdef _GTHREAD_USE_COND_INIT_FUNC
+static inline void
+__gthread_cond_init_function (__gthread_cond_t *__cond)
+{
+  if (__gthread_active_p ())
+    __gthrw_(pthread_cond_init) (__cond, NULL);
+}
+#endif
+
+static inline int
+__gthread_cond_broadcast (__gthread_cond_t *__cond)
+{
+  return __gthrw_(pthread_cond_broadcast) (__cond);
+}
+
+static inline int
+__gthread_cond_signal (__gthread_cond_t *__cond)
+{
+  return __gthrw_(pthread_cond_signal) (__cond);
+}
+
+static inline int
+__gthread_cond_wait (__gthread_cond_t *__cond, __gthread_mutex_t *__mutex)
+{
+  return __gthrw_(pthread_cond_wait) (__cond, __mutex);
+}
+
+static inline int
+__gthread_cond_timedwait (__gthread_cond_t *__cond, __gthread_mutex_t *__mutex,
+			  const __gthread_time_t *__abs_timeout)
+{
+  return __gthrw_(pthread_cond_timedwait) (__cond, __mutex, __abs_timeout);
+}
+
+static inline int
+__gthread_cond_wait_recursive (__gthread_cond_t *__cond,
+			       __gthread_recursive_mutex_t *__mutex)
+{
+  return __gthread_cond_wait (__cond, __mutex);
+}
+
+static inline int
+__gthread_cond_destroy (__gthread_cond_t* __cond)
+{
+  return __gthrw_(pthread_cond_destroy) (__cond);
+}
+
+#endif /* _LIBOBJC */
+
+#endif /* ! _GLIBCXX_GCC_GTHR_POSIX_H */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@x86_64-unknown-linux-gnu@bits@gthr-default.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@x86_64-unknown-linux-gnu@bits@gthr-default.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@x86_64-unknown-linux-gnu@bits@gthr.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@x86_64-unknown-linux-gnu@bits@gthr.h
new file mode 100644
index 0000000000000000000000000000000000000000..51fabc3c7ded6a2f54ac6a35be30fed09ef1c393
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@x86_64-unknown-linux-gnu@bits@gthr.h
@@ -0,0 +1,154 @@
+/* Threads compatibility routines for libgcc2.  */
+/* Compile this one with gcc.  */
+/* Copyright (C) 1997-2022 Free Software Foundation, Inc.
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 3, or (at your option) any later
+version.
+
+GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+Under Section 7 of GPL version 3, you are granted additional
+permissions described in the GCC Runtime Library Exception, version
+3.1, as published by the Free Software Foundation.
+
+You should have received a copy of the GNU General Public License and
+a copy of the GCC Runtime Library Exception along with this program;
+see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+<http://www.gnu.org/licenses/>.  */
+
+#ifndef _GLIBCXX_GCC_GTHR_H
+#define _GLIBCXX_GCC_GTHR_H
+
+#ifndef _GLIBCXX_HIDE_EXPORTS
+#pragma GCC visibility push(default)
+#endif
+
+/* If this file is compiled with threads support, it must
+       #define __GTHREADS 1
+   to indicate that threads support is present.  Also it has define
+   function
+     int __gthread_active_p ()
+   that returns 1 if thread system is active, 0 if not.
+
+   The threads interface must define the following types:
+     __gthread_key_t
+     __gthread_once_t
+     __gthread_mutex_t
+     __gthread_recursive_mutex_t
+
+   The threads interface must define the following macros:
+
+     __GTHREAD_ONCE_INIT
+     		to initialize __gthread_once_t
+     __GTHREAD_MUTEX_INIT
+     		to initialize __gthread_mutex_t to get a fast
+		non-recursive mutex.
+     __GTHREAD_MUTEX_INIT_FUNCTION
+		to initialize __gthread_mutex_t to get a fast
+		non-recursive mutex.
+		Define this to a function which looks like this:
+		  void __GTHREAD_MUTEX_INIT_FUNCTION (__gthread_mutex_t *)
+     		Some systems can't initialize a mutex without a
+		function call.  Don't define __GTHREAD_MUTEX_INIT in this case.
+     __GTHREAD_RECURSIVE_MUTEX_INIT
+     __GTHREAD_RECURSIVE_MUTEX_INIT_FUNCTION
+     		as above, but for a recursive mutex.
+
+   The threads interface must define the following static functions:
+
+     int __gthread_once (__gthread_once_t *once, void (*func) ())
+
+     int __gthread_key_create (__gthread_key_t *keyp, void (*dtor) (void *))
+     int __gthread_key_delete (__gthread_key_t key)
+
+     void *__gthread_getspecific (__gthread_key_t key)
+     int __gthread_setspecific (__gthread_key_t key, const void *ptr)
+
+     int __gthread_mutex_destroy (__gthread_mutex_t *mutex);
+     int __gthread_recursive_mutex_destroy (__gthread_recursive_mutex_t *mutex);
+
+     int __gthread_mutex_lock (__gthread_mutex_t *mutex);
+     int __gthread_mutex_trylock (__gthread_mutex_t *mutex);
+     int __gthread_mutex_unlock (__gthread_mutex_t *mutex);
+
+     int __gthread_recursive_mutex_lock (__gthread_recursive_mutex_t *mutex);
+     int __gthread_recursive_mutex_trylock (__gthread_recursive_mutex_t *mutex);
+     int __gthread_recursive_mutex_unlock (__gthread_recursive_mutex_t *mutex);
+
+   The following are supported in POSIX threads only. They are required to
+   fix a deadlock in static initialization inside libsupc++. The header file
+   gthr-posix.h defines a symbol __GTHREAD_HAS_COND to signify that these extra
+   features are supported.
+
+   Types:
+     __gthread_cond_t
+
+   Macros:
+     __GTHREAD_COND_INIT
+     __GTHREAD_COND_INIT_FUNCTION
+
+   Interface:
+     int __gthread_cond_broadcast (__gthread_cond_t *cond);
+     int __gthread_cond_wait (__gthread_cond_t *cond, __gthread_mutex_t *mutex);
+     int __gthread_cond_wait_recursive (__gthread_cond_t *cond,
+					__gthread_recursive_mutex_t *mutex);
+
+   All functions returning int should return zero on success or the error
+   number.  If the operation is not supported, -1 is returned.
+
+   If the following are also defined, you should
+     #define __GTHREADS_CXX0X 1
+   to enable the c++0x thread library.
+
+   Types:
+     __gthread_t
+     __gthread_time_t
+
+   Interface:
+     int __gthread_create (__gthread_t *thread, void *(*func) (void*),
+                           void *args);
+     int __gthread_join (__gthread_t thread, void **value_ptr);
+     int __gthread_detach (__gthread_t thread);
+     int __gthread_equal (__gthread_t t1, __gthread_t t2);
+     __gthread_t __gthread_self (void);
+     int __gthread_yield (void);
+
+     int __gthread_mutex_timedlock (__gthread_mutex_t *m,
+                                    const __gthread_time_t *abs_timeout);
+     int __gthread_recursive_mutex_timedlock (__gthread_recursive_mutex_t *m,
+                                          const __gthread_time_t *abs_time);
+
+     int __gthread_cond_signal (__gthread_cond_t *cond);
+     int __gthread_cond_timedwait (__gthread_cond_t *cond,
+                                   __gthread_mutex_t *mutex,
+                                   const __gthread_time_t *abs_timeout);
+
+*/
+
+#if __GXX_WEAK__
+/* The pe-coff weak support isn't fully compatible to ELF's weak.
+   For static libraries it might would work, but as we need to deal
+   with shared versions too, we disable it for mingw-targets.  */
+#ifdef __MINGW32__
+#undef _GLIBCXX_GTHREAD_USE_WEAK
+#define _GLIBCXX_GTHREAD_USE_WEAK 0
+#endif
+
+#ifndef _GLIBCXX_GTHREAD_USE_WEAK
+#define _GLIBCXX_GTHREAD_USE_WEAK 1
+#endif
+#endif
+#include <bits/gthr-default.h>
+
+#ifndef _GLIBCXX_HIDE_EXPORTS
+#pragma GCC visibility pop
+#endif
+
+#endif /* ! _GLIBCXX_GCC_GTHR_H */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@x86_64-unknown-linux-gnu@bits@gthr.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@x86_64-unknown-linux-gnu@bits@gthr.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@x86_64-unknown-linux-gnu@bits@messages_members.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@x86_64-unknown-linux-gnu@bits@messages_members.h
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--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@x86_64-unknown-linux-gnu@bits@messages_members.h
@@ -0,0 +1,151 @@
+// std::messages implementation details, GNU version -*- C++ -*-
+
+// Copyright (C) 2001-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/messages_members.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{locale}
+ */
+
+//
+// ISO C++ 14882: 22.2.7.1.2  messages functions
+//
+
+// Written by Benjamin Kosnik <bkoz@redhat.com>
+
+#include <libintl.h>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  // Non-virtual member functions.
+  template<typename _CharT>
+    messages<_CharT>::messages(size_t __refs)
+    : facet(__refs), _M_c_locale_messages(_S_get_c_locale()),
+      _M_name_messages(_S_get_c_name())
+    { }
+
+  template<typename _CharT>
+    messages<_CharT>::messages(__c_locale __cloc, const char* __s,
+			       size_t __refs)
+    : facet(__refs), _M_c_locale_messages(0), _M_name_messages(0)
+    {
+      if (__builtin_strcmp(__s, _S_get_c_name()) != 0)
+	{
+	  const size_t __len = __builtin_strlen(__s) + 1;
+	  char* __tmp = new char[__len];
+	  __builtin_memcpy(__tmp, __s, __len);
+	  _M_name_messages = __tmp;
+	}
+      else
+	_M_name_messages = _S_get_c_name();
+
+      // Last to avoid leaking memory if new throws.
+      _M_c_locale_messages = _S_clone_c_locale(__cloc);
+    }
+
+  template<typename _CharT>
+    typename messages<_CharT>::catalog
+    messages<_CharT>::open(const basic_string<char>& __s, const locale& __loc,
+			   const char* __dir) const
+    {
+      bindtextdomain(__s.c_str(), __dir);
+      return this->do_open(__s, __loc);
+    }
+
+  // Virtual member functions.
+  template<typename _CharT>
+    messages<_CharT>::~messages()
+    {
+      if (_M_name_messages != _S_get_c_name())
+	delete [] _M_name_messages;
+      _S_destroy_c_locale(_M_c_locale_messages);
+    }
+
+  template<typename _CharT>
+    typename messages<_CharT>::catalog
+    messages<_CharT>::do_open(const basic_string<char>& __s,
+			      const locale&) const
+    {
+      // No error checking is done, assume the catalog exists and can
+      // be used.
+      textdomain(__s.c_str());
+      return 0;
+    }
+
+  template<typename _CharT>
+    void
+    messages<_CharT>::do_close(catalog) const
+    { }
+
+  // messages_byname
+  template<typename _CharT>
+    messages_byname<_CharT>::messages_byname(const char* __s, size_t __refs)
+    : messages<_CharT>(__refs)
+    {
+      if (this->_M_name_messages != locale::facet::_S_get_c_name())
+	{
+	  delete [] this->_M_name_messages;
+	  if (__builtin_strcmp(__s, locale::facet::_S_get_c_name()) != 0)
+	    {
+	      const size_t __len = __builtin_strlen(__s) + 1;
+	      char* __tmp = new char[__len];
+	      __builtin_memcpy(__tmp, __s, __len);
+	      this->_M_name_messages = __tmp;
+	    }
+	  else
+	    this->_M_name_messages = locale::facet::_S_get_c_name();
+	}
+
+      if (__builtin_strcmp(__s, "C") != 0
+	  && __builtin_strcmp(__s, "POSIX") != 0)
+	{
+	  this->_S_destroy_c_locale(this->_M_c_locale_messages);
+	  this->_S_create_c_locale(this->_M_c_locale_messages, __s);
+	}
+    }
+
+   //Specializations.
+  template<>
+    typename messages<char>::catalog
+    messages<char>::do_open(const basic_string<char>&,
+			    const locale&) const;
+
+  template<>
+    void
+    messages<char>::do_close(catalog) const;
+
+#ifdef _GLIBCXX_USE_WCHAR_T
+  template<>
+    typename messages<wchar_t>::catalog
+    messages<wchar_t>::do_open(const basic_string<char>&,
+			       const locale&) const;
+
+  template<>
+    void
+    messages<wchar_t>::do_close(catalog) const;
+#endif
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@x86_64-unknown-linux-gnu@bits@messages_members.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@x86_64-unknown-linux-gnu@bits@messages_members.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@x86_64-unknown-linux-gnu@bits@opt_random.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@x86_64-unknown-linux-gnu@bits@opt_random.h
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--- /dev/null
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@@ -0,0 +1,221 @@
+// Optimizations for random number functions, x86 version -*- C++ -*-
+
+// Copyright (C) 2012-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/opt_random.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{random}
+ */
+
+#ifndef _BITS_OPT_RANDOM_H
+#define _BITS_OPT_RANDOM_H 1
+
+#ifdef __SSE3__
+#include <pmmintrin.h>
+#endif
+
+
+#pragma GCC system_header
+
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+#ifdef __SSE3__
+  template<>
+    template<typename _UniformRandomNumberGenerator>
+      void
+      normal_distribution<double>::
+      __generate(typename normal_distribution<double>::result_type* __f,
+		 typename normal_distribution<double>::result_type* __t,
+		 _UniformRandomNumberGenerator& __urng,
+		 const param_type& __param)
+      {
+	typedef uint64_t __uctype;
+
+	if (__f == __t)
+	  return;
+
+	if (_M_saved_available)
+	  {
+	    _M_saved_available = false;
+	    *__f++ = _M_saved * __param.stddev() + __param.mean();
+
+	    if (__f == __t)
+	      return;
+	  }
+
+	constexpr uint64_t __maskval = 0xfffffffffffffull;
+	static const __m128i __mask = _mm_set1_epi64x(__maskval);
+	static const __m128i __two = _mm_set1_epi64x(0x4000000000000000ull);
+	static const __m128d __three = _mm_set1_pd(3.0);
+	const __m128d __av = _mm_set1_pd(__param.mean());
+
+	const __uctype __urngmin = __urng.min();
+	const __uctype __urngmax = __urng.max();
+	const __uctype __urngrange = __urngmax - __urngmin;
+	const __uctype __uerngrange = __urngrange + 1;
+
+	while (__f + 1 < __t)
+	  {
+	    double __le;
+	    __m128d __x;
+	    do
+	      {
+                union
+                {
+                  __m128i __i;
+                  __m128d __d;
+		} __v;
+
+		if (__urngrange > __maskval)
+		  {
+		    if (__detail::_Power_of_2(__uerngrange))
+		      __v.__i = _mm_and_si128(_mm_set_epi64x(__urng(),
+							     __urng()),
+					      __mask);
+		    else
+		      {
+			const __uctype __uerange = __maskval + 1;
+			const __uctype __scaling = __urngrange / __uerange;
+			const __uctype __past = __uerange * __scaling;
+			uint64_t __v1;
+			do
+			  __v1 = __uctype(__urng()) - __urngmin;
+			while (__v1 >= __past);
+			__v1 /= __scaling;
+			uint64_t __v2;
+			do
+			  __v2 = __uctype(__urng()) - __urngmin;
+			while (__v2 >= __past);
+			__v2 /= __scaling;
+
+			__v.__i = _mm_set_epi64x(__v1, __v2);
+		      }
+		  }
+		else if (__urngrange == __maskval)
+		  __v.__i = _mm_set_epi64x(__urng(), __urng());
+		else if ((__urngrange + 2) * __urngrange >= __maskval
+			 && __detail::_Power_of_2(__uerngrange))
+		  {
+		    uint64_t __v1 = __urng() * __uerngrange + __urng();
+		    uint64_t __v2 = __urng() * __uerngrange + __urng();
+
+		    __v.__i = _mm_and_si128(_mm_set_epi64x(__v1, __v2),
+					    __mask);
+		  }
+		else
+		  {
+		    size_t __nrng = 2;
+		    __uctype __high = __maskval / __uerngrange / __uerngrange;
+		    while (__high > __uerngrange)
+		      {
+			++__nrng;
+			__high /= __uerngrange;
+		      }
+		    const __uctype __highrange = __high + 1;
+		    const __uctype __scaling = __urngrange / __highrange;
+		    const __uctype __past = __highrange * __scaling;
+		    __uctype __tmp;
+
+		    uint64_t __v1;
+		    do
+		      {
+			do
+			  __tmp = __uctype(__urng()) - __urngmin;
+			while (__tmp >= __past);
+			__v1 = __tmp / __scaling;
+			for (size_t __cnt = 0; __cnt < __nrng; ++__cnt)
+			  {
+			    __tmp = __v1;
+			    __v1 *= __uerngrange;
+			    __v1 += __uctype(__urng()) - __urngmin;
+			  }
+		      }
+		    while (__v1 > __maskval || __v1 < __tmp);
+
+		    uint64_t __v2;
+		    do
+		      {
+			do
+			  __tmp = __uctype(__urng()) - __urngmin;
+			while (__tmp >= __past);
+			__v2 = __tmp / __scaling;
+			for (size_t __cnt = 0; __cnt < __nrng; ++__cnt)
+			  {
+			    __tmp = __v2;
+			    __v2 *= __uerngrange;
+			    __v2 += __uctype(__urng()) - __urngmin;
+			  }
+		      }
+		    while (__v2 > __maskval || __v2 < __tmp);
+
+		    __v.__i = _mm_set_epi64x(__v1, __v2);
+		  }
+
+		__v.__i = _mm_or_si128(__v.__i, __two);
+		__x = _mm_sub_pd(__v.__d, __three);
+		__m128d __m = _mm_mul_pd(__x, __x);
+		__le = _mm_cvtsd_f64(_mm_hadd_pd (__m, __m));
+              }
+            while (__le == 0.0 || __le >= 1.0);
+
+            double __mult = (std::sqrt(-2.0 * std::log(__le) / __le)
+                             * __param.stddev());
+
+            __x = _mm_add_pd(_mm_mul_pd(__x, _mm_set1_pd(__mult)), __av);
+
+            _mm_storeu_pd(__f, __x);
+            __f += 2;
+          }
+
+        if (__f != __t)
+          {
+            result_type __x, __y, __r2;
+
+            __detail::_Adaptor<_UniformRandomNumberGenerator, result_type>
+              __aurng(__urng);
+
+            do
+              {
+                __x = result_type(2.0) * __aurng() - 1.0;
+                __y = result_type(2.0) * __aurng() - 1.0;
+                __r2 = __x * __x + __y * __y;
+              }
+            while (__r2 > 1.0 || __r2 == 0.0);
+
+            const result_type __mult = std::sqrt(-2 * std::log(__r2) / __r2);
+            _M_saved = __x * __mult;
+            _M_saved_available = true;
+            *__f = __y * __mult * __param.stddev() + __param.mean();
+          }
+      }
+#endif
+
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+
+#endif // _BITS_OPT_RANDOM_H
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@x86_64-unknown-linux-gnu@bits@opt_random.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@x86_64-unknown-linux-gnu@bits@opt_random.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@x86_64-unknown-linux-gnu@bits@os_defines.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@x86_64-unknown-linux-gnu@bits@os_defines.h
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@@ -0,0 +1,70 @@
+// Specific definitions for GNU/Linux  -*- C++ -*-
+
+// Copyright (C) 2000-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/os_defines.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{iosfwd}
+ */
+
+#ifndef _GLIBCXX_OS_DEFINES
+#define _GLIBCXX_OS_DEFINES 1
+
+// System-specific #define, typedefs, corrections, etc, go here.  This
+// file will come before all others.
+
+// This keeps isalnum, et al from being propagated as macros.
+#define __NO_CTYPE 1
+
+#include <features.h>
+
+// Provide a declaration for the possibly deprecated gets function, as
+// glibc 2.15 and later does not declare gets for ISO C11 when
+// __GNU_SOURCE is defined.
+#if __GLIBC_PREREQ(2,15) && defined(_GNU_SOURCE)
+# undef _GLIBCXX_HAVE_GETS
+#endif
+
+// Glibc 2.23 removed the obsolete isinf and isnan declarations. Check the
+// version dynamically in case it has changed since libstdc++ was configured.
+#define _GLIBCXX_NO_OBSOLETE_ISINF_ISNAN_DYNAMIC __GLIBC_PREREQ(2,23)
+
+#if __GLIBC_PREREQ(2, 27)
+// Since glibc 2.27 pthread_self() is usable without linking to libpthread.
+# define _GLIBCXX_NATIVE_THREAD_ID pthread_self()
+#else
+// Before then it was in libc.so.6 but not libc.a, and always returns 0,
+// which breaks the invariant this_thread::get_id() != thread::id{}.
+// So only use it if we know the libpthread version is available.
+// Otherwise use (__gthread_t)1 as the ID of the main (and only) thread.
+# define _GLIBCXX_NATIVE_THREAD_ID \
+  (__gthread_active_p() ? __gthread_self() : (__gthread_t)1)
+#endif
+
+#if __GLIBC_PREREQ(2, 34)
+// Since glibc 2.34 all pthreads functions are usable without linking to
+// libpthread.
+# define _GLIBCXX_GTHREAD_USE_WEAK 0
+#endif
+
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@x86_64-unknown-linux-gnu@bits@os_defines.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@x86_64-unknown-linux-gnu@bits@os_defines.h.blob
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new file mode 100644
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--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@x86_64-unknown-linux-gnu@bits@stdc++.h
@@ -0,0 +1,162 @@
+// C++ includes used for precompiling -*- C++ -*-
+
+// Copyright (C) 2003-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file stdc++.h
+ *  This is an implementation file for a precompiled header.
+ */
+
+// 17.4.1.2 Headers
+
+// C
+#ifndef _GLIBCXX_NO_ASSERT
+#include <cassert>
+#endif
+#include <cctype>
+#include <cerrno>
+#include <cfloat>
+#include <ciso646>
+#include <climits>
+#include <clocale>
+#include <cmath>
+#include <csetjmp>
+#include <csignal>
+#include <cstdarg>
+#include <cstddef>
+#include <cstdio>
+#include <cstdlib>
+#include <cstring>
+#include <ctime>
+#include <cwchar>
+#include <cwctype>
+
+#if __cplusplus >= 201103L
+#include <ccomplex>
+#include <cfenv>
+#include <cinttypes>
+#include <cstdalign>
+#include <cstdbool>
+#include <cstdint>
+#include <ctgmath>
+#include <cuchar>
+#endif
+
+// C++
+#include <algorithm>
+#include <bitset>
+#include <complex>
+#include <deque>
+#include <exception>
+#include <fstream>
+#include <functional>
+#include <iomanip>
+#include <ios>
+#include <iosfwd>
+#include <iostream>
+#include <istream>
+#include <iterator>
+#include <limits>
+#include <list>
+#include <locale>
+#include <map>
+#include <memory>
+#include <new>
+#include <numeric>
+#include <ostream>
+#include <queue>
+#include <set>
+#include <sstream>
+#include <stack>
+#include <stdexcept>
+#include <streambuf>
+#include <string>
+#include <typeinfo>
+#include <utility>
+#include <valarray>
+#include <vector>
+
+#if __cplusplus >= 201103L
+#include <array>
+#include <atomic>
+#include <chrono>
+#include <codecvt>
+#include <condition_variable>
+#include <forward_list>
+#include <future>
+#include <initializer_list>
+#include <mutex>
+#include <random>
+#include <ratio>
+#include <regex>
+#include <scoped_allocator>
+#include <system_error>
+#include <thread>
+#include <tuple>
+#include <typeindex>
+#include <type_traits>
+#include <unordered_map>
+#include <unordered_set>
+#endif
+
+#if __cplusplus >= 201402L
+#include <shared_mutex>
+#endif
+
+#if __cplusplus >= 201703L
+#include <any>
+#include <charconv>
+// #include <execution>
+#include <filesystem>
+#include <optional>
+#include <memory_resource>
+#include <string_view>
+#include <variant>
+#endif
+
+#if __cplusplus >= 202002L
+#include <barrier>
+#include <bit>
+#include <compare>
+#include <concepts>
+#if __cpp_impl_coroutine
+# include <coroutine>
+#endif
+#include <latch>
+#include <numbers>
+#include <ranges>
+#include <span>
+#include <stop_token>
+#include <semaphore>
+#include <source_location>
+#include <syncstream>
+#include <version>
+#endif
+
+#if __cplusplus > 202002L
+#include <expected>
+#include <spanstream>
+#if __has_include(<stacktrace>)
+# include <stacktrace>
+#endif
+#include <stdatomic.h>
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@x86_64-unknown-linux-gnu@bits@stdc++.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@x86_64-unknown-linux-gnu@bits@stdc++.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@x86_64-unknown-linux-gnu@bits@time_members.h b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@x86_64-unknown-linux-gnu@bits@time_members.h
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+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@x86_64-unknown-linux-gnu@bits@time_members.h
@@ -0,0 +1,89 @@
+// std::time_get, std::time_put implementation, GNU version -*- C++ -*-
+
+// Copyright (C) 2001-2022 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/time_members.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{locale}
+ */
+
+//
+// ISO C++ 14882: 22.2.5.1.2 - time_get functions
+// ISO C++ 14882: 22.2.5.3.2 - time_put functions
+//
+
+// Written by Benjamin Kosnik <bkoz@redhat.com>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  template<typename _CharT>
+    __timepunct<_CharT>::__timepunct(size_t __refs)
+    : facet(__refs), _M_data(0), _M_c_locale_timepunct(0),
+      _M_name_timepunct(_S_get_c_name())
+    { _M_initialize_timepunct(); }
+
+  template<typename _CharT>
+    __timepunct<_CharT>::__timepunct(__cache_type* __cache, size_t __refs)
+    : facet(__refs), _M_data(__cache), _M_c_locale_timepunct(0),
+      _M_name_timepunct(_S_get_c_name())
+    { _M_initialize_timepunct(); }
+
+  template<typename _CharT>
+    __timepunct<_CharT>::__timepunct(__c_locale __cloc, const char* __s,
+				     size_t __refs)
+    : facet(__refs), _M_data(0), _M_c_locale_timepunct(0),
+      _M_name_timepunct(0)
+    {
+      if (__builtin_strcmp(__s, _S_get_c_name()) != 0)
+	{
+	  const size_t __len = __builtin_strlen(__s) + 1;
+	  char* __tmp = new char[__len];
+	  __builtin_memcpy(__tmp, __s, __len);
+	  _M_name_timepunct = __tmp;
+	}
+      else
+	_M_name_timepunct = _S_get_c_name();
+
+      __try
+	{ _M_initialize_timepunct(__cloc); }
+      __catch(...)
+	{
+	  if (_M_name_timepunct != _S_get_c_name())
+	    delete [] _M_name_timepunct;
+	  __throw_exception_again;
+	}
+    }
+
+  template<typename _CharT>
+    __timepunct<_CharT>::~__timepunct()
+    {
+      if (_M_name_timepunct != _S_get_c_name())
+	delete [] _M_name_timepunct;
+      delete _M_data;
+      _S_destroy_c_locale(_M_c_locale_timepunct);
+    }
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@x86_64-unknown-linux-gnu@bits@time_members.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0@include@c++@12.2.0@x86_64-unknown-linux-gnu@bits@time_members.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@rf7mgm3kn47ifbkyvvd87m8jkf4yc14p-clang-14.0.6-lib@lib@clang@14.0.6@include@__stddef_max_align_t.h b/.ccls-cache/@@root@gpt-vue/@nix@store@rf7mgm3kn47ifbkyvvd87m8jkf4yc14p-clang-14.0.6-lib@lib@clang@14.0.6@include@__stddef_max_align_t.h
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@@ -0,0 +1,27 @@
+/*===---- __stddef_max_align_t.h - Definition of max_align_t for modules ---===
+ *
+ * Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+ * See https://llvm.org/LICENSE.txt for license information.
+ * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+ *
+ *===-----------------------------------------------------------------------===
+ */
+
+#ifndef __CLANG_MAX_ALIGN_T_DEFINED
+#define __CLANG_MAX_ALIGN_T_DEFINED
+
+#if defined(_MSC_VER)
+typedef double max_align_t;
+#elif defined(__APPLE__)
+typedef long double max_align_t;
+#else
+// Define 'max_align_t' to match the GCC definition.
+typedef struct {
+  long long __clang_max_align_nonce1
+      __attribute__((__aligned__(__alignof__(long long))));
+  long double __clang_max_align_nonce2
+      __attribute__((__aligned__(__alignof__(long double))));
+} max_align_t;
+#endif
+
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@rf7mgm3kn47ifbkyvvd87m8jkf4yc14p-clang-14.0.6-lib@lib@clang@14.0.6@include@__stddef_max_align_t.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@rf7mgm3kn47ifbkyvvd87m8jkf4yc14p-clang-14.0.6-lib@lib@clang@14.0.6@include@__stddef_max_align_t.h.blob
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@@ -0,0 +1,161 @@
+/*===---- float.h - Characteristics of floating point types ----------------===
+ *
+ * Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+ * See https://llvm.org/LICENSE.txt for license information.
+ * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+ *
+ *===-----------------------------------------------------------------------===
+ */
+
+#ifndef __CLANG_FLOAT_H
+#define __CLANG_FLOAT_H
+
+/* If we're on MinGW, fall back to the system's float.h, which might have
+ * additional definitions provided for Windows.
+ * For more details see http://msdn.microsoft.com/en-us/library/y0ybw9fy.aspx
+ *
+ * Also fall back on Darwin and AIX to allow additional definitions and
+ * implementation-defined values.
+ */
+#if (defined(__APPLE__) || defined(__MINGW32__) || defined(_MSC_VER) ||        \
+     defined(_AIX)) &&                                                         \
+    __STDC_HOSTED__ && __has_include_next(<float.h>)
+
+/* Prior to Apple's 10.7 SDK, float.h SDK header used to apply an extra level
+ * of #include_next<float.h> to keep Metrowerks compilers happy. Avoid this
+ * extra indirection.
+ */
+#ifdef __APPLE__
+#define _FLOAT_H_
+#endif
+
+#  include_next <float.h>
+
+/* Undefine anything that we'll be redefining below. */
+#  undef FLT_EVAL_METHOD
+#  undef FLT_ROUNDS
+#  undef FLT_RADIX
+#  undef FLT_MANT_DIG
+#  undef DBL_MANT_DIG
+#  undef LDBL_MANT_DIG
+#  if __STDC_VERSION__ >= 199901L || !defined(__STRICT_ANSI__) ||              \
+      __cplusplus >= 201103L ||                                                \
+      (__STDC_HOSTED__ && defined(_AIX) && defined(_ALL_SOURCE))
+#    undef DECIMAL_DIG
+#  endif
+#  undef FLT_DIG
+#  undef DBL_DIG
+#  undef LDBL_DIG
+#  undef FLT_MIN_EXP
+#  undef DBL_MIN_EXP
+#  undef LDBL_MIN_EXP
+#  undef FLT_MIN_10_EXP
+#  undef DBL_MIN_10_EXP
+#  undef LDBL_MIN_10_EXP
+#  undef FLT_MAX_EXP
+#  undef DBL_MAX_EXP
+#  undef LDBL_MAX_EXP
+#  undef FLT_MAX_10_EXP
+#  undef DBL_MAX_10_EXP
+#  undef LDBL_MAX_10_EXP
+#  undef FLT_MAX
+#  undef DBL_MAX
+#  undef LDBL_MAX
+#  undef FLT_EPSILON
+#  undef DBL_EPSILON
+#  undef LDBL_EPSILON
+#  undef FLT_MIN
+#  undef DBL_MIN
+#  undef LDBL_MIN
+#  if __STDC_VERSION__ >= 201112L || !defined(__STRICT_ANSI__) ||              \
+      __cplusplus >= 201703L ||                                                \
+      (__STDC_HOSTED__ && defined(_AIX) && defined(_ALL_SOURCE))
+#    undef FLT_TRUE_MIN
+#    undef DBL_TRUE_MIN
+#    undef LDBL_TRUE_MIN
+#    undef FLT_DECIMAL_DIG
+#    undef DBL_DECIMAL_DIG
+#    undef LDBL_DECIMAL_DIG
+#    undef FLT_HAS_SUBNORM
+#    undef DBL_HAS_SUBNORM
+#    undef LDBL_HAS_SUBNORM
+#  endif
+#endif
+
+/* Characteristics of floating point types, C99 5.2.4.2.2 */
+
+#define FLT_EVAL_METHOD __FLT_EVAL_METHOD__
+#define FLT_ROUNDS (__builtin_flt_rounds())
+#define FLT_RADIX __FLT_RADIX__
+
+#define FLT_MANT_DIG __FLT_MANT_DIG__
+#define DBL_MANT_DIG __DBL_MANT_DIG__
+#define LDBL_MANT_DIG __LDBL_MANT_DIG__
+
+#if __STDC_VERSION__ >= 199901L || !defined(__STRICT_ANSI__) ||                \
+    __cplusplus >= 201103L ||                                                  \
+    (__STDC_HOSTED__ && defined(_AIX) && defined(_ALL_SOURCE))
+#  define DECIMAL_DIG __DECIMAL_DIG__
+#endif
+
+#define FLT_DIG __FLT_DIG__
+#define DBL_DIG __DBL_DIG__
+#define LDBL_DIG __LDBL_DIG__
+
+#define FLT_MIN_EXP __FLT_MIN_EXP__
+#define DBL_MIN_EXP __DBL_MIN_EXP__
+#define LDBL_MIN_EXP __LDBL_MIN_EXP__
+
+#define FLT_MIN_10_EXP __FLT_MIN_10_EXP__
+#define DBL_MIN_10_EXP __DBL_MIN_10_EXP__
+#define LDBL_MIN_10_EXP __LDBL_MIN_10_EXP__
+
+#define FLT_MAX_EXP __FLT_MAX_EXP__
+#define DBL_MAX_EXP __DBL_MAX_EXP__
+#define LDBL_MAX_EXP __LDBL_MAX_EXP__
+
+#define FLT_MAX_10_EXP __FLT_MAX_10_EXP__
+#define DBL_MAX_10_EXP __DBL_MAX_10_EXP__
+#define LDBL_MAX_10_EXP __LDBL_MAX_10_EXP__
+
+#define FLT_MAX __FLT_MAX__
+#define DBL_MAX __DBL_MAX__
+#define LDBL_MAX __LDBL_MAX__
+
+#define FLT_EPSILON __FLT_EPSILON__
+#define DBL_EPSILON __DBL_EPSILON__
+#define LDBL_EPSILON __LDBL_EPSILON__
+
+#define FLT_MIN __FLT_MIN__
+#define DBL_MIN __DBL_MIN__
+#define LDBL_MIN __LDBL_MIN__
+
+#if __STDC_VERSION__ >= 201112L || !defined(__STRICT_ANSI__) ||                \
+    __cplusplus >= 201703L ||                                                  \
+    (__STDC_HOSTED__ && defined(_AIX) && defined(_ALL_SOURCE))
+#  define FLT_TRUE_MIN __FLT_DENORM_MIN__
+#  define DBL_TRUE_MIN __DBL_DENORM_MIN__
+#  define LDBL_TRUE_MIN __LDBL_DENORM_MIN__
+#  define FLT_DECIMAL_DIG __FLT_DECIMAL_DIG__
+#  define DBL_DECIMAL_DIG __DBL_DECIMAL_DIG__
+#  define LDBL_DECIMAL_DIG __LDBL_DECIMAL_DIG__
+#  define FLT_HAS_SUBNORM __FLT_HAS_DENORM__
+#  define DBL_HAS_SUBNORM __DBL_HAS_DENORM__
+#  define LDBL_HAS_SUBNORM __LDBL_HAS_DENORM__
+#endif
+
+#ifdef __STDC_WANT_IEC_60559_TYPES_EXT__
+#  define FLT16_MANT_DIG    __FLT16_MANT_DIG__
+#  define FLT16_DECIMAL_DIG __FLT16_DECIMAL_DIG__
+#  define FLT16_DIG         __FLT16_DIG__
+#  define FLT16_MIN_EXP     __FLT16_MIN_EXP__
+#  define FLT16_MIN_10_EXP  __FLT16_MIN_10_EXP__
+#  define FLT16_MAX_EXP     __FLT16_MAX_EXP__
+#  define FLT16_MAX_10_EXP  __FLT16_MAX_10_EXP__
+#  define FLT16_MAX         __FLT16_MAX__
+#  define FLT16_EPSILON     __FLT16_EPSILON__
+#  define FLT16_MIN         __FLT16_MIN__
+#  define FLT16_TRUE_MIN    __FLT16_TRUE_MIN__
+#endif /* __STDC_WANT_IEC_60559_TYPES_EXT__ */
+
+#endif /* __CLANG_FLOAT_H */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@rf7mgm3kn47ifbkyvvd87m8jkf4yc14p-clang-14.0.6-lib@lib@clang@14.0.6@include@float.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@rf7mgm3kn47ifbkyvvd87m8jkf4yc14p-clang-14.0.6-lib@lib@clang@14.0.6@include@float.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@rf7mgm3kn47ifbkyvvd87m8jkf4yc14p-clang-14.0.6-lib@lib@clang@14.0.6@include@inttypes.h b/.ccls-cache/@@root@gpt-vue/@nix@store@rf7mgm3kn47ifbkyvvd87m8jkf4yc14p-clang-14.0.6-lib@lib@clang@14.0.6@include@inttypes.h
new file mode 100644
index 0000000000000000000000000000000000000000..1c894c4aca4975d7439ed3abda221818dbc57e94
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@rf7mgm3kn47ifbkyvvd87m8jkf4yc14p-clang-14.0.6-lib@lib@clang@14.0.6@include@inttypes.h
@@ -0,0 +1,97 @@
+/*===---- inttypes.h - Standard header for integer printf macros ----------===*\
+ *
+ * Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+ * See https://llvm.org/LICENSE.txt for license information.
+ * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+ *
+\*===----------------------------------------------------------------------===*/
+
+#ifndef __CLANG_INTTYPES_H
+// AIX system headers need inttypes.h to be re-enterable while _STD_TYPES_T
+// is defined until an inclusion of it without _STD_TYPES_T occurs, in which
+// case the header guard macro is defined.
+#if !defined(_AIX) || !defined(_STD_TYPES_T)
+#define __CLANG_INTTYPES_H
+#endif
+
+#if defined(_MSC_VER) && _MSC_VER < 1800
+#error MSVC does not have inttypes.h prior to Visual Studio 2013
+#endif
+
+#include_next <inttypes.h>
+
+#if defined(_MSC_VER) && _MSC_VER < 1900
+/* MSVC headers define int32_t as int, but PRIx32 as "lx" instead of "x".
+ * This triggers format warnings, so fix it up here. */
+#undef PRId32
+#undef PRIdLEAST32
+#undef PRIdFAST32
+#undef PRIi32
+#undef PRIiLEAST32
+#undef PRIiFAST32
+#undef PRIo32
+#undef PRIoLEAST32
+#undef PRIoFAST32
+#undef PRIu32
+#undef PRIuLEAST32
+#undef PRIuFAST32
+#undef PRIx32
+#undef PRIxLEAST32
+#undef PRIxFAST32
+#undef PRIX32
+#undef PRIXLEAST32
+#undef PRIXFAST32
+
+#undef SCNd32
+#undef SCNdLEAST32
+#undef SCNdFAST32
+#undef SCNi32
+#undef SCNiLEAST32
+#undef SCNiFAST32
+#undef SCNo32
+#undef SCNoLEAST32
+#undef SCNoFAST32
+#undef SCNu32
+#undef SCNuLEAST32
+#undef SCNuFAST32
+#undef SCNx32
+#undef SCNxLEAST32
+#undef SCNxFAST32
+
+#define PRId32 "d"
+#define PRIdLEAST32 "d"
+#define PRIdFAST32 "d"
+#define PRIi32 "i"
+#define PRIiLEAST32 "i"
+#define PRIiFAST32 "i"
+#define PRIo32 "o"
+#define PRIoLEAST32 "o"
+#define PRIoFAST32 "o"
+#define PRIu32 "u"
+#define PRIuLEAST32 "u"
+#define PRIuFAST32 "u"
+#define PRIx32 "x"
+#define PRIxLEAST32 "x"
+#define PRIxFAST32 "x"
+#define PRIX32 "X"
+#define PRIXLEAST32 "X"
+#define PRIXFAST32 "X"
+
+#define SCNd32 "d"
+#define SCNdLEAST32 "d"
+#define SCNdFAST32 "d"
+#define SCNi32 "i"
+#define SCNiLEAST32 "i"
+#define SCNiFAST32 "i"
+#define SCNo32 "o"
+#define SCNoLEAST32 "o"
+#define SCNoFAST32 "o"
+#define SCNu32 "u"
+#define SCNuLEAST32 "u"
+#define SCNuFAST32 "u"
+#define SCNx32 "x"
+#define SCNxLEAST32 "x"
+#define SCNxFAST32 "x"
+#endif
+
+#endif /* __CLANG_INTTYPES_H */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@rf7mgm3kn47ifbkyvvd87m8jkf4yc14p-clang-14.0.6-lib@lib@clang@14.0.6@include@inttypes.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@rf7mgm3kn47ifbkyvvd87m8jkf4yc14p-clang-14.0.6-lib@lib@clang@14.0.6@include@inttypes.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@rf7mgm3kn47ifbkyvvd87m8jkf4yc14p-clang-14.0.6-lib@lib@clang@14.0.6@include@limits.h b/.ccls-cache/@@root@gpt-vue/@nix@store@rf7mgm3kn47ifbkyvvd87m8jkf4yc14p-clang-14.0.6-lib@lib@clang@14.0.6@include@limits.h
new file mode 100644
index 0000000000000000000000000000000000000000..cfd23a219ee553a868a03f3363d5d32c1662375a
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@rf7mgm3kn47ifbkyvvd87m8jkf4yc14p-clang-14.0.6-lib@lib@clang@14.0.6@include@limits.h
@@ -0,0 +1,122 @@
+/*===---- limits.h - Standard header for integer sizes --------------------===*\
+ *
+ * Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+ * See https://llvm.org/LICENSE.txt for license information.
+ * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+ *
+\*===----------------------------------------------------------------------===*/
+
+#ifndef __CLANG_LIMITS_H
+#define __CLANG_LIMITS_H
+
+/* The system's limits.h may, in turn, try to #include_next GCC's limits.h.
+   Avert this #include_next madness. */
+#if defined __GNUC__ && !defined _GCC_LIMITS_H_
+#define _GCC_LIMITS_H_
+#endif
+
+/* System headers include a number of constants from POSIX in <limits.h>.
+   Include it if we're hosted. */
+#if __STDC_HOSTED__ && __has_include_next(<limits.h>)
+#include_next <limits.h>
+#endif
+
+/* Many system headers try to "help us out" by defining these.  No really, we
+   know how big each datatype is. */
+#undef  SCHAR_MIN
+#undef  SCHAR_MAX
+#undef  UCHAR_MAX
+#undef  SHRT_MIN
+#undef  SHRT_MAX
+#undef  USHRT_MAX
+#undef  INT_MIN
+#undef  INT_MAX
+#undef  UINT_MAX
+#undef  LONG_MIN
+#undef  LONG_MAX
+#undef  ULONG_MAX
+
+#undef  CHAR_BIT
+#undef  CHAR_MIN
+#undef  CHAR_MAX
+
+/* C90/99 5.2.4.2.1 */
+#define SCHAR_MAX __SCHAR_MAX__
+#define SHRT_MAX  __SHRT_MAX__
+#define INT_MAX   __INT_MAX__
+#define LONG_MAX  __LONG_MAX__
+
+#define SCHAR_MIN (-__SCHAR_MAX__-1)
+#define SHRT_MIN  (-__SHRT_MAX__ -1)
+#define INT_MIN   (-__INT_MAX__  -1)
+#define LONG_MIN  (-__LONG_MAX__ -1L)
+
+#define UCHAR_MAX (__SCHAR_MAX__*2  +1)
+#define USHRT_MAX (__SHRT_MAX__ *2  +1)
+#define UINT_MAX  (__INT_MAX__  *2U +1U)
+#define ULONG_MAX (__LONG_MAX__ *2UL+1UL)
+
+#ifndef MB_LEN_MAX
+#define MB_LEN_MAX 1
+#endif
+
+#define CHAR_BIT  __CHAR_BIT__
+
+/* C2x 5.2.4.2.1 */
+/* FIXME: This is using the placeholder dates Clang produces for these macros
+   in C2x mode; switch to the correct values once they've been published. */
+#if __STDC_VERSION__ >= 202000L
+#define BOOL_WIDTH   __BOOL_WIDTH__
+#define CHAR_WIDTH   CHAR_BIT
+#define SCHAR_WIDTH  CHAR_BIT
+#define UCHAR_WIDTH  CHAR_BIT
+#define USHRT_WIDTH  __SHRT_WIDTH__
+#define SHRT_WIDTH   __SHRT_WIDTH__
+#define UINT_WIDTH   __INT_WIDTH__
+#define INT_WIDTH    __INT_WIDTH__
+#define ULONG_WIDTH  __LONG_WIDTH__
+#define LONG_WIDTH   __LONG_WIDTH__
+#define ULLONG_WIDTH __LLONG_WIDTH__
+#define LLONG_WIDTH  __LLONG_WIDTH__
+
+#define BITINT_MAXWIDTH __BITINT_MAXWIDTH__
+#endif
+
+#ifdef __CHAR_UNSIGNED__  /* -funsigned-char */
+#define CHAR_MIN 0
+#define CHAR_MAX UCHAR_MAX
+#else
+#define CHAR_MIN SCHAR_MIN
+#define CHAR_MAX __SCHAR_MAX__
+#endif
+
+/* C99 5.2.4.2.1: Added long long.
+   C++11 18.3.3.2: same contents as the Standard C Library header <limits.h>.
+ */
+#if __STDC_VERSION__ >= 199901L || __cplusplus >= 201103L
+
+#undef  LLONG_MIN
+#undef  LLONG_MAX
+#undef  ULLONG_MAX
+
+#define LLONG_MAX  __LONG_LONG_MAX__
+#define LLONG_MIN  (-__LONG_LONG_MAX__-1LL)
+#define ULLONG_MAX (__LONG_LONG_MAX__*2ULL+1ULL)
+#endif
+
+/* LONG_LONG_MIN/LONG_LONG_MAX/ULONG_LONG_MAX are a GNU extension.  It's too bad
+   that we don't have something like #pragma poison that could be used to
+   deprecate a macro - the code should just use LLONG_MAX and friends.
+ */
+#if defined(__GNU_LIBRARY__) ? defined(__USE_GNU) : !defined(__STRICT_ANSI__)
+
+#undef   LONG_LONG_MIN
+#undef   LONG_LONG_MAX
+#undef   ULONG_LONG_MAX
+
+#define LONG_LONG_MAX  __LONG_LONG_MAX__
+#define LONG_LONG_MIN  (-__LONG_LONG_MAX__-1LL)
+#define ULONG_LONG_MAX (__LONG_LONG_MAX__*2ULL+1ULL)
+#endif
+
+#endif /* __CLANG_LIMITS_H */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@rf7mgm3kn47ifbkyvvd87m8jkf4yc14p-clang-14.0.6-lib@lib@clang@14.0.6@include@limits.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@rf7mgm3kn47ifbkyvvd87m8jkf4yc14p-clang-14.0.6-lib@lib@clang@14.0.6@include@limits.h.blob
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diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@rf7mgm3kn47ifbkyvvd87m8jkf4yc14p-clang-14.0.6-lib@lib@clang@14.0.6@include@stdalign.h b/.ccls-cache/@@root@gpt-vue/@nix@store@rf7mgm3kn47ifbkyvvd87m8jkf4yc14p-clang-14.0.6-lib@lib@clang@14.0.6@include@stdalign.h
new file mode 100644
index 0000000000000000000000000000000000000000..6ad25db4539a1359146a428b3f2b8e646bdeae7b
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@rf7mgm3kn47ifbkyvvd87m8jkf4yc14p-clang-14.0.6-lib@lib@clang@14.0.6@include@stdalign.h
@@ -0,0 +1,21 @@
+/*===---- stdalign.h - Standard header for alignment ------------------------===
+ *
+ * Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+ * See https://llvm.org/LICENSE.txt for license information.
+ * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+ *
+ *===-----------------------------------------------------------------------===
+ */
+
+#ifndef __STDALIGN_H
+#define __STDALIGN_H
+
+#ifndef __cplusplus
+#define alignas _Alignas
+#define alignof _Alignof
+#endif
+
+#define __alignas_is_defined 1
+#define __alignof_is_defined 1
+
+#endif /* __STDALIGN_H */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@rf7mgm3kn47ifbkyvvd87m8jkf4yc14p-clang-14.0.6-lib@lib@clang@14.0.6@include@stdalign.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@rf7mgm3kn47ifbkyvvd87m8jkf4yc14p-clang-14.0.6-lib@lib@clang@14.0.6@include@stdalign.h.blob
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new file mode 100644
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--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@rf7mgm3kn47ifbkyvvd87m8jkf4yc14p-clang-14.0.6-lib@lib@clang@14.0.6@include@stdarg.h
@@ -0,0 +1,35 @@
+/*===---- stdarg.h - Variable argument handling ----------------------------===
+ *
+ * Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+ * See https://llvm.org/LICENSE.txt for license information.
+ * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+ *
+ *===-----------------------------------------------------------------------===
+ */
+
+#ifndef __STDARG_H
+#define __STDARG_H
+
+#ifndef _VA_LIST
+typedef __builtin_va_list va_list;
+#define _VA_LIST
+#endif
+#define va_start(ap, param) __builtin_va_start(ap, param)
+#define va_end(ap)          __builtin_va_end(ap)
+#define va_arg(ap, type)    __builtin_va_arg(ap, type)
+
+/* GCC always defines __va_copy, but does not define va_copy unless in c99 mode
+ * or -ansi is not specified, since it was not part of C90.
+ */
+#define __va_copy(d,s) __builtin_va_copy(d,s)
+
+#if __STDC_VERSION__ >= 199901L || __cplusplus >= 201103L || !defined(__STRICT_ANSI__)
+#define va_copy(dest, src)  __builtin_va_copy(dest, src)
+#endif
+
+#ifndef __GNUC_VA_LIST
+#define __GNUC_VA_LIST 1
+typedef __builtin_va_list __gnuc_va_list;
+#endif
+
+#endif /* __STDARG_H */
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--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@rf7mgm3kn47ifbkyvvd87m8jkf4yc14p-clang-14.0.6-lib@lib@clang@14.0.6@include@stdbool.h
@@ -0,0 +1,31 @@
+/*===---- stdbool.h - Standard header for booleans -------------------------===
+ *
+ * Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+ * See https://llvm.org/LICENSE.txt for license information.
+ * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+ *
+ *===-----------------------------------------------------------------------===
+ */
+
+#ifndef __STDBOOL_H
+#define __STDBOOL_H
+
+/* Don't define bool, true, and false in C++, except as a GNU extension. */
+#ifndef __cplusplus
+#define bool _Bool
+#define true 1
+#define false 0
+#elif defined(__GNUC__) && !defined(__STRICT_ANSI__)
+/* Define _Bool as a GNU extension. */
+#define _Bool bool
+#if __cplusplus < 201103L
+/* For C++98, define bool, false, true as a GNU extension. */
+#define bool  bool
+#define false false
+#define true  true
+#endif
+#endif
+
+#define __bool_true_false_are_defined 1
+
+#endif /* __STDBOOL_H */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@rf7mgm3kn47ifbkyvvd87m8jkf4yc14p-clang-14.0.6-lib@lib@clang@14.0.6@include@stdbool.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@rf7mgm3kn47ifbkyvvd87m8jkf4yc14p-clang-14.0.6-lib@lib@clang@14.0.6@include@stdbool.h.blob
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Binary files /dev/null and b/.ccls-cache/@@root@gpt-vue/@nix@store@rf7mgm3kn47ifbkyvvd87m8jkf4yc14p-clang-14.0.6-lib@lib@clang@14.0.6@include@stdbool.h.blob differ
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@rf7mgm3kn47ifbkyvvd87m8jkf4yc14p-clang-14.0.6-lib@lib@clang@14.0.6@include@stddef.h b/.ccls-cache/@@root@gpt-vue/@nix@store@rf7mgm3kn47ifbkyvvd87m8jkf4yc14p-clang-14.0.6-lib@lib@clang@14.0.6@include@stddef.h
new file mode 100644
index 0000000000000000000000000000000000000000..15acd4427ca14000111aad5071563bc7f2dc09f4
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@rf7mgm3kn47ifbkyvvd87m8jkf4yc14p-clang-14.0.6-lib@lib@clang@14.0.6@include@stddef.h
@@ -0,0 +1,121 @@
+/*===---- stddef.h - Basic type definitions --------------------------------===
+ *
+ * Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+ * See https://llvm.org/LICENSE.txt for license information.
+ * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+ *
+ *===-----------------------------------------------------------------------===
+ */
+
+#if !defined(__STDDEF_H) || defined(__need_ptrdiff_t) ||                       \
+    defined(__need_size_t) || defined(__need_wchar_t) ||                       \
+    defined(__need_NULL) || defined(__need_wint_t)
+
+#if !defined(__need_ptrdiff_t) && !defined(__need_size_t) &&                   \
+    !defined(__need_wchar_t) && !defined(__need_NULL) &&                       \
+    !defined(__need_wint_t)
+/* Always define miscellaneous pieces when modules are available. */
+#if !__has_feature(modules)
+#define __STDDEF_H
+#endif
+#define __need_ptrdiff_t
+#define __need_size_t
+#define __need_wchar_t
+#define __need_NULL
+#define __need_STDDEF_H_misc
+/* __need_wint_t is intentionally not defined here. */
+#endif
+
+#if defined(__need_ptrdiff_t)
+#if !defined(_PTRDIFF_T) || __has_feature(modules)
+/* Always define ptrdiff_t when modules are available. */
+#if !__has_feature(modules)
+#define _PTRDIFF_T
+#endif
+typedef __PTRDIFF_TYPE__ ptrdiff_t;
+#endif
+#undef __need_ptrdiff_t
+#endif /* defined(__need_ptrdiff_t) */
+
+#if defined(__need_size_t)
+#if !defined(_SIZE_T) || __has_feature(modules)
+/* Always define size_t when modules are available. */
+#if !__has_feature(modules)
+#define _SIZE_T
+#endif
+typedef __SIZE_TYPE__ size_t;
+#endif
+#undef __need_size_t
+#endif /*defined(__need_size_t) */
+
+#if defined(__need_STDDEF_H_misc)
+/* ISO9899:2011 7.20 (C11 Annex K): Define rsize_t if __STDC_WANT_LIB_EXT1__ is
+ * enabled. */
+#if (defined(__STDC_WANT_LIB_EXT1__) && __STDC_WANT_LIB_EXT1__ >= 1 && \
+     !defined(_RSIZE_T)) || __has_feature(modules)
+/* Always define rsize_t when modules are available. */
+#if !__has_feature(modules)
+#define _RSIZE_T
+#endif
+typedef __SIZE_TYPE__ rsize_t;
+#endif
+#endif /* defined(__need_STDDEF_H_misc) */
+
+#if defined(__need_wchar_t)
+#ifndef __cplusplus
+/* Always define wchar_t when modules are available. */
+#if !defined(_WCHAR_T) || __has_feature(modules)
+#if !__has_feature(modules)
+#define _WCHAR_T
+#if defined(_MSC_EXTENSIONS)
+#define _WCHAR_T_DEFINED
+#endif
+#endif
+typedef __WCHAR_TYPE__ wchar_t;
+#endif
+#endif
+#undef __need_wchar_t
+#endif /* defined(__need_wchar_t) */
+
+#if defined(__need_NULL)
+#undef NULL
+#ifdef __cplusplus
+#  if !defined(__MINGW32__) && !defined(_MSC_VER)
+#    define NULL __null
+#  else
+#    define NULL 0
+#  endif
+#else
+#  define NULL ((void*)0)
+#endif
+#ifdef __cplusplus
+#if defined(_MSC_EXTENSIONS) && defined(_NATIVE_NULLPTR_SUPPORTED)
+namespace std { typedef decltype(nullptr) nullptr_t; }
+using ::std::nullptr_t;
+#endif
+#endif
+#undef __need_NULL
+#endif /* defined(__need_NULL) */
+
+#if defined(__need_STDDEF_H_misc)
+#if __STDC_VERSION__ >= 201112L || __cplusplus >= 201103L
+#include "__stddef_max_align_t.h"
+#endif
+#define offsetof(t, d) __builtin_offsetof(t, d)
+#undef __need_STDDEF_H_misc
+#endif  /* defined(__need_STDDEF_H_misc) */
+
+/* Some C libraries expect to see a wint_t here. Others (notably MinGW) will use
+__WINT_TYPE__ directly; accommodate both by requiring __need_wint_t */
+#if defined(__need_wint_t)
+/* Always define wint_t when modules are available. */
+#if !defined(_WINT_T) || __has_feature(modules)
+#if !__has_feature(modules)
+#define _WINT_T
+#endif
+typedef __WINT_TYPE__ wint_t;
+#endif
+#undef __need_wint_t
+#endif /* __need_wint_t */
+
+#endif
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@rf7mgm3kn47ifbkyvvd87m8jkf4yc14p-clang-14.0.6-lib@lib@clang@14.0.6@include@stddef.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@rf7mgm3kn47ifbkyvvd87m8jkf4yc14p-clang-14.0.6-lib@lib@clang@14.0.6@include@stddef.h.blob
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index 0000000000000000000000000000000000000000..030fa99cdc69cf00131f3c830a5edcb660030dca
Binary files /dev/null and b/.ccls-cache/@@root@gpt-vue/@nix@store@rf7mgm3kn47ifbkyvvd87m8jkf4yc14p-clang-14.0.6-lib@lib@clang@14.0.6@include@stddef.h.blob differ
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@rf7mgm3kn47ifbkyvvd87m8jkf4yc14p-clang-14.0.6-lib@lib@clang@14.0.6@include@stdint.h b/.ccls-cache/@@root@gpt-vue/@nix@store@rf7mgm3kn47ifbkyvvd87m8jkf4yc14p-clang-14.0.6-lib@lib@clang@14.0.6@include@stdint.h
new file mode 100644
index 0000000000000000000000000000000000000000..4790c25a2774bad0d5928c1c94aa10768912bb50
--- /dev/null
+++ b/.ccls-cache/@@root@gpt-vue/@nix@store@rf7mgm3kn47ifbkyvvd87m8jkf4yc14p-clang-14.0.6-lib@lib@clang@14.0.6@include@stdint.h
@@ -0,0 +1,861 @@
+/*===---- stdint.h - Standard header for sized integer types --------------===*\
+ *
+ * Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+ * See https://llvm.org/LICENSE.txt for license information.
+ * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+ *
+\*===----------------------------------------------------------------------===*/
+
+#ifndef __CLANG_STDINT_H
+// AIX system headers need stdint.h to be re-enterable while _STD_TYPES_T
+// is defined until an inclusion of it without _STD_TYPES_T occurs, in which
+// case the header guard macro is defined.
+#if !defined(_AIX) || !defined(_STD_TYPES_T) || !defined(__STDC_HOSTED__)
+#define __CLANG_STDINT_H
+#endif
+
+/* If we're hosted, fall back to the system's stdint.h, which might have
+ * additional definitions.
+ */
+#if __STDC_HOSTED__ && __has_include_next(<stdint.h>)
+
+// C99 7.18.3 Limits of other integer types
+//
+//  Footnote 219, 220: C++ implementations should define these macros only when
+//  __STDC_LIMIT_MACROS is defined before <stdint.h> is included.
+//
+//  Footnote 222: C++ implementations should define these macros only when
+//  __STDC_CONSTANT_MACROS is defined before <stdint.h> is included.
+//
+// C++11 [cstdint.syn]p2:
+//
+//  The macros defined by <cstdint> are provided unconditionally. In particular,
+//  the symbols __STDC_LIMIT_MACROS and __STDC_CONSTANT_MACROS (mentioned in
+//  footnotes 219, 220, and 222 in the C standard) play no role in C++.
+//
+// C11 removed the problematic footnotes.
+//
+// Work around this inconsistency by always defining those macros in C++ mode,
+// so that a C library implementation which follows the C99 standard can be
+// used in C++.
+# ifdef __cplusplus
+#  if !defined(__STDC_LIMIT_MACROS)
+#   define __STDC_LIMIT_MACROS
+#   define __STDC_LIMIT_MACROS_DEFINED_BY_CLANG
+#  endif
+#  if !defined(__STDC_CONSTANT_MACROS)
+#   define __STDC_CONSTANT_MACROS
+#   define __STDC_CONSTANT_MACROS_DEFINED_BY_CLANG
+#  endif
+# endif
+
+# include_next <stdint.h>
+
+# ifdef __STDC_LIMIT_MACROS_DEFINED_BY_CLANG
+#  undef __STDC_LIMIT_MACROS
+#  undef __STDC_LIMIT_MACROS_DEFINED_BY_CLANG
+# endif
+# ifdef __STDC_CONSTANT_MACROS_DEFINED_BY_CLANG
+#  undef __STDC_CONSTANT_MACROS
+#  undef __STDC_CONSTANT_MACROS_DEFINED_BY_CLANG
+# endif
+
+#else
+
+/* C99 7.18.1.1 Exact-width integer types.
+ * C99 7.18.1.2 Minimum-width integer types.
+ * C99 7.18.1.3 Fastest minimum-width integer types.
+ *
+ * The standard requires that exact-width type be defined for 8-, 16-, 32-, and
+ * 64-bit types if they are implemented. Other exact width types are optional.
+ * This implementation defines an exact-width types for every integer width
+ * that is represented in the standard integer types.
+ *
+ * The standard also requires minimum-width types be defined for 8-, 16-, 32-,
+ * and 64-bit widths regardless of whether there are corresponding exact-width
+ * types.
+ *
+ * To accommodate targets that are missing types that are exactly 8, 16, 32, or
+ * 64 bits wide, this implementation takes an approach of cascading
+ * redefinitions, redefining __int_leastN_t to successively smaller exact-width
+ * types. It is therefore important that the types are defined in order of
+ * descending widths.
+ *
+ * We currently assume that the minimum-width types and the fastest
+ * minimum-width types are the same. This is allowed by the standard, but is
+ * suboptimal.
+ *
+ * In violation of the standard, some targets do not implement a type that is
+ * wide enough to represent all of the required widths (8-, 16-, 32-, 64-bit).
+ * To accommodate these targets, a required minimum-width type is only
+ * defined if there exists an exact-width type of equal or greater width.
+ */
+
+#ifdef __INT64_TYPE__
+# ifndef __int8_t_defined /* glibc sys/types.h also defines int64_t*/
+typedef __INT64_TYPE__ int64_t;
+# endif /* __int8_t_defined */
+typedef __UINT64_TYPE__ uint64_t;
+# define __int_least64_t int64_t
+# define __uint_least64_t uint64_t
+# define __int_least32_t int64_t
+# define __uint_least32_t uint64_t
+# define __int_least16_t int64_t
+# define __uint_least16_t uint64_t
+# define __int_least8_t int64_t
+# define __uint_least8_t uint64_t
+#endif /* __INT64_TYPE__ */
+
+#ifdef __int_least64_t
+typedef __int_least64_t int_least64_t;
+typedef __uint_least64_t uint_least64_t;
+typedef __int_least64_t int_fast64_t;
+typedef __uint_least64_t uint_fast64_t;
+#endif /* __int_least64_t */
+
+#ifdef __INT56_TYPE__
+typedef __INT56_TYPE__ int56_t;
+typedef __UINT56_TYPE__ uint56_t;
+typedef int56_t int_least56_t;
+typedef uint56_t uint_least56_t;
+typedef int56_t int_fast56_t;
+typedef uint56_t uint_fast56_t;
+# define __int_least32_t int56_t
+# define __uint_least32_t uint56_t
+# define __int_least16_t int56_t
+# define __uint_least16_t uint56_t
+# define __int_least8_t int56_t
+# define __uint_least8_t uint56_t
+#endif /* __INT56_TYPE__ */
+
+
+#ifdef __INT48_TYPE__
+typedef __INT48_TYPE__ int48_t;
+typedef __UINT48_TYPE__ uint48_t;
+typedef int48_t int_least48_t;
+typedef uint48_t uint_least48_t;
+typedef int48_t int_fast48_t;
+typedef uint48_t uint_fast48_t;
+# define __int_least32_t int48_t
+# define __uint_least32_t uint48_t
+# define __int_least16_t int48_t
+# define __uint_least16_t uint48_t
+# define __int_least8_t int48_t
+# define __uint_least8_t uint48_t
+#endif /* __INT48_TYPE__ */
+
+
+#ifdef __INT40_TYPE__
+typedef __INT40_TYPE__ int40_t;
+typedef __UINT40_TYPE__ uint40_t;
+typedef int40_t int_least40_t;
+typedef uint40_t uint_least40_t;
+typedef int40_t int_fast40_t;
+typedef uint40_t uint_fast40_t;
+# define __int_least32_t int40_t
+# define __uint_least32_t uint40_t
+# define __int_least16_t int40_t
+# define __uint_least16_t uint40_t
+# define __int_least8_t int40_t
+# define __uint_least8_t uint40_t
+#endif /* __INT40_TYPE__ */
+
+
+#ifdef __INT32_TYPE__
+
+# ifndef __int8_t_defined /* glibc sys/types.h also defines int32_t*/
+typedef __INT32_TYPE__ int32_t;
+# endif /* __int8_t_defined */
+
+# ifndef __uint32_t_defined  /* more glibc compatibility */
+# define __uint32_t_defined
+typedef __UINT32_TYPE__ uint32_t;
+# endif /* __uint32_t_defined */
+
+# define __int_least32_t int32_t
+# define __uint_least32_t uint32_t
+# define __int_least16_t int32_t
+# define __uint_least16_t uint32_t
+# define __int_least8_t int32_t
+# define __uint_least8_t uint32_t
+#endif /* __INT32_TYPE__ */
+
+#ifdef __int_least32_t
+typedef __int_least32_t int_least32_t;
+typedef __uint_least32_t uint_least32_t;
+typedef __int_least32_t int_fast32_t;
+typedef __uint_least32_t uint_fast32_t;
+#endif /* __int_least32_t */
+
+#ifdef __INT24_TYPE__
+typedef __INT24_TYPE__ int24_t;
+typedef __UINT24_TYPE__ uint24_t;
+typedef int24_t int_least24_t;
+typedef uint24_t uint_least24_t;
+typedef int24_t int_fast24_t;
+typedef uint24_t uint_fast24_t;
+# define __int_least16_t int24_t
+# define __uint_least16_t uint24_t
+# define __int_least8_t int24_t
+# define __uint_least8_t uint24_t
+#endif /* __INT24_TYPE__ */
+
+#ifdef __INT16_TYPE__
+#ifndef __int8_t_defined /* glibc sys/types.h also defines int16_t*/
+typedef __INT16_TYPE__ int16_t;
+#endif /* __int8_t_defined */
+typedef __UINT16_TYPE__ uint16_t;
+# define __int_least16_t int16_t
+# define __uint_least16_t uint16_t
+# define __int_least8_t int16_t
+# define __uint_least8_t uint16_t
+#endif /* __INT16_TYPE__ */
+
+#ifdef __int_least16_t
+typedef __int_least16_t int_least16_t;
+typedef __uint_least16_t uint_least16_t;
+typedef __int_least16_t int_fast16_t;
+typedef __uint_least16_t uint_fast16_t;
+#endif /* __int_least16_t */
+
+
+#ifdef __INT8_TYPE__
+#ifndef __int8_t_defined  /* glibc sys/types.h also defines int8_t*/
+typedef __INT8_TYPE__ int8_t;
+#endif /* __int8_t_defined */
+typedef __UINT8_TYPE__ uint8_t;
+# define __int_least8_t int8_t
+# define __uint_least8_t uint8_t
+#endif /* __INT8_TYPE__ */
+
+#ifdef __int_least8_t
+typedef __int_least8_t int_least8_t;
+typedef __uint_least8_t uint_least8_t;
+typedef __int_least8_t int_fast8_t;
+typedef __uint_least8_t uint_fast8_t;
+#endif /* __int_least8_t */
+
+/* prevent glibc sys/types.h from defining conflicting types */
+#ifndef __int8_t_defined
+# define __int8_t_defined
+#endif /* __int8_t_defined */
+
+/* C99 7.18.1.4 Integer types capable of holding object pointers.
+ */
+#define __stdint_join3(a,b,c) a ## b ## c
+
+#ifndef _INTPTR_T
+#ifndef __intptr_t_defined
+typedef __INTPTR_TYPE__ intptr_t;
+#define __intptr_t_defined
+#define _INTPTR_T
+#endif
+#endif
+
+#ifndef _UINTPTR_T
+typedef __UINTPTR_TYPE__ uintptr_t;
+#define _UINTPTR_T
+#endif
+
+/* C99 7.18.1.5 Greatest-width integer types.
+ */
+typedef __INTMAX_TYPE__  intmax_t;
+typedef __UINTMAX_TYPE__ uintmax_t;
+
+/* C99 7.18.4 Macros for minimum-width integer constants.
+ *
+ * The standard requires that integer constant macros be defined for all the
+ * minimum-width types defined above. As 8-, 16-, 32-, and 64-bit minimum-width
+ * types are required, the corresponding integer constant macros are defined
+ * here. This implementation also defines minimum-width types for every other
+ * integer width that the target implements, so corresponding macros are
+ * defined below, too.
+ *
+ * These macros are defined using the same successive-shrinking approach as
+ * the type definitions above. It is likewise important that macros are defined
+ * in order of decending width.
+ *
+ * Note that C++ should not check __STDC_CONSTANT_MACROS here, contrary to the
+ * claims of the C standard (see C++ 18.3.1p2, [cstdint.syn]).
+ */
+
+#define __int_c_join(a, b) a ## b
+#define __int_c(v, suffix) __int_c_join(v, suffix)
+#define __uint_c(v, suffix) __int_c_join(v##U, suffix)
+
+
+#ifdef __INT64_TYPE__
+# ifdef __INT64_C_SUFFIX__
+#  define __int64_c_suffix __INT64_C_SUFFIX__
+#  define __int32_c_suffix __INT64_C_SUFFIX__
+#  define __int16_c_suffix __INT64_C_SUFFIX__
+#  define  __int8_c_suffix __INT64_C_SUFFIX__
+# else
+#  undef __int64_c_suffix
+#  undef __int32_c_suffix
+#  undef __int16_c_suffix
+#  undef  __int8_c_suffix
+# endif /* __INT64_C_SUFFIX__ */
+#endif /* __INT64_TYPE__ */
+
+#ifdef __int_least64_t
+# ifdef __int64_c_suffix
+#  define INT64_C(v) __int_c(v, __int64_c_suffix)
+#  define UINT64_C(v) __uint_c(v, __int64_c_suffix)
+# else
+#  define INT64_C(v) v
+#  define UINT64_C(v) v ## U
+# endif /* __int64_c_suffix */
+#endif /* __int_least64_t */
+
+
+#ifdef __INT56_TYPE__
+# ifdef __INT56_C_SUFFIX__
+#  define INT56_C(v) __int_c(v, __INT56_C_SUFFIX__)
+#  define UINT56_C(v) __uint_c(v, __INT56_C_SUFFIX__)
+#  define __int32_c_suffix __INT56_C_SUFFIX__
+#  define __int16_c_suffix __INT56_C_SUFFIX__
+#  define __int8_c_suffix  __INT56_C_SUFFIX__
+# else
+#  define INT56_C(v) v
+#  define UINT56_C(v) v ## U
+#  undef __int32_c_suffix
+#  undef __int16_c_suffix
+#  undef  __int8_c_suffix
+# endif /* __INT56_C_SUFFIX__ */
+#endif /* __INT56_TYPE__ */
+
+
+#ifdef __INT48_TYPE__
+# ifdef __INT48_C_SUFFIX__
+#  define INT48_C(v) __int_c(v, __INT48_C_SUFFIX__)
+#  define UINT48_C(v) __uint_c(v, __INT48_C_SUFFIX__)
+#  define __int32_c_suffix __INT48_C_SUFFIX__
+#  define __int16_c_suffix __INT48_C_SUFFIX__
+#  define __int8_c_suffix  __INT48_C_SUFFIX__
+# else
+#  define INT48_C(v) v
+#  define UINT48_C(v) v ## U
+#  undef __int32_c_suffix
+#  undef __int16_c_suffix
+#  undef  __int8_c_suffix
+# endif /* __INT48_C_SUFFIX__ */
+#endif /* __INT48_TYPE__ */
+
+
+#ifdef __INT40_TYPE__
+# ifdef __INT40_C_SUFFIX__
+#  define INT40_C(v) __int_c(v, __INT40_C_SUFFIX__)
+#  define UINT40_C(v) __uint_c(v, __INT40_C_SUFFIX__)
+#  define __int32_c_suffix __INT40_C_SUFFIX__
+#  define __int16_c_suffix __INT40_C_SUFFIX__
+#  define __int8_c_suffix  __INT40_C_SUFFIX__
+# else
+#  define INT40_C(v) v
+#  define UINT40_C(v) v ## U
+#  undef __int32_c_suffix
+#  undef __int16_c_suffix
+#  undef  __int8_c_suffix
+# endif /* __INT40_C_SUFFIX__ */
+#endif /* __INT40_TYPE__ */
+
+
+#ifdef __INT32_TYPE__
+# ifdef __INT32_C_SUFFIX__
+#  define __int32_c_suffix __INT32_C_SUFFIX__
+#  define __int16_c_suffix __INT32_C_SUFFIX__
+#  define __int8_c_suffix  __INT32_C_SUFFIX__
+#else
+#  undef __int32_c_suffix
+#  undef __int16_c_suffix
+#  undef  __int8_c_suffix
+# endif /* __INT32_C_SUFFIX__ */
+#endif /* __INT32_TYPE__ */
+
+#ifdef __int_least32_t
+# ifdef __int32_c_suffix
+#  define INT32_C(v) __int_c(v, __int32_c_suffix)
+#  define UINT32_C(v) __uint_c(v, __int32_c_suffix)
+# else
+#  define INT32_C(v) v
+#  define UINT32_C(v) v ## U
+# endif /* __int32_c_suffix */
+#endif /* __int_least32_t */
+
+
+#ifdef __INT24_TYPE__
+# ifdef __INT24_C_SUFFIX__
+#  define INT24_C(v) __int_c(v, __INT24_C_SUFFIX__)
+#  define UINT24_C(v) __uint_c(v, __INT24_C_SUFFIX__)
+#  define __int16_c_suffix __INT24_C_SUFFIX__
+#  define __int8_c_suffix  __INT24_C_SUFFIX__
+# else
+#  define INT24_C(v) v
+#  define UINT24_C(v) v ## U
+#  undef __int16_c_suffix
+#  undef  __int8_c_suffix
+# endif /* __INT24_C_SUFFIX__ */
+#endif /* __INT24_TYPE__ */
+
+
+#ifdef __INT16_TYPE__
+# ifdef __INT16_C_SUFFIX__
+#  define __int16_c_suffix __INT16_C_SUFFIX__
+#  define __int8_c_suffix  __INT16_C_SUFFIX__
+#else
+#  undef __int16_c_suffix
+#  undef  __int8_c_suffix
+# endif /* __INT16_C_SUFFIX__ */
+#endif /* __INT16_TYPE__ */
+
+#ifdef __int_least16_t
+# ifdef __int16_c_suffix
+#  define INT16_C(v) __int_c(v, __int16_c_suffix)
+#  define UINT16_C(v) __uint_c(v, __int16_c_suffix)
+# else
+#  define INT16_C(v) v
+#  define UINT16_C(v) v ## U
+# endif /* __int16_c_suffix */
+#endif /* __int_least16_t */
+
+
+#ifdef __INT8_TYPE__
+# ifdef __INT8_C_SUFFIX__
+#  define __int8_c_suffix __INT8_C_SUFFIX__
+#else
+#  undef  __int8_c_suffix
+# endif /* __INT8_C_SUFFIX__ */
+#endif /* __INT8_TYPE__ */
+
+#ifdef __int_least8_t
+# ifdef __int8_c_suffix
+#  define INT8_C(v) __int_c(v, __int8_c_suffix)
+#  define UINT8_C(v) __uint_c(v, __int8_c_suffix)
+# else
+#  define INT8_C(v) v
+#  define UINT8_C(v) v ## U
+# endif /* __int8_c_suffix */
+#endif /* __int_least8_t */
+
+
+/* C99 7.18.2.1 Limits of exact-width integer types.
+ * C99 7.18.2.2 Limits of minimum-width integer types.
+ * C99 7.18.2.3 Limits of fastest minimum-width integer types.
+ *
+ * The presence of limit macros are completely optional in C99.  This
+ * implementation defines limits for all of the types (exact- and
+ * minimum-width) that it defines above, using the limits of the minimum-width
+ * type for any types that do not have exact-width representations.
+ *
+ * As in the type definitions, this section takes an approach of
+ * successive-shrinking to determine which limits to use for the standard (8,
+ * 16, 32, 64) bit widths when they don't have exact representations. It is
+ * therefore important that the definitions be kept in order of decending
+ * widths.
+ *
+ * Note that C++ should not check __STDC_LIMIT_MACROS here, contrary to the
+ * claims of the C standard (see C++ 18.3.1p2, [cstdint.syn]).
+ */
+
+#ifdef __INT64_TYPE__
+# define INT64_MAX           INT64_C( 9223372036854775807)
+# define INT64_MIN         (-INT64_C( 9223372036854775807)-1)
+# define UINT64_MAX         UINT64_C(18446744073709551615)
+/* FIXME: This is using the placeholder dates Clang produces for these macros
+   in C2x mode; switch to the correct values once they've been published. */
+#if __STDC_VERSION__ >= 202000L
+# define UINT64_WIDTH         64
+# define INT64_WIDTH          UINT64_WIDTH
+
+# define __UINT_LEAST64_WIDTH UINT64_WIDTH
+# define __UINT_LEAST32_WIDTH UINT64_WIDTH
+# define __UINT_LEAST16_WIDTH UINT64_WIDTH
+# define __UINT_LEAST8_MAX UINT64_MAX
+#endif /* __STDC_VERSION__ */
+
+# define __INT_LEAST64_MIN   INT64_MIN
+# define __INT_LEAST64_MAX   INT64_MAX
+# define __UINT_LEAST64_MAX UINT64_MAX
+# define __INT_LEAST32_MIN   INT64_MIN
+# define __INT_LEAST32_MAX   INT64_MAX
+# define __UINT_LEAST32_MAX UINT64_MAX
+# define __INT_LEAST16_MIN   INT64_MIN
+# define __INT_LEAST16_MAX   INT64_MAX
+# define __UINT_LEAST16_MAX UINT64_MAX
+# define __INT_LEAST8_MIN    INT64_MIN
+# define __INT_LEAST8_MAX    INT64_MAX
+# define __UINT_LEAST8_MAX  UINT64_MAX
+#endif /* __INT64_TYPE__ */
+
+#ifdef __INT_LEAST64_MIN
+# define INT_LEAST64_MIN   __INT_LEAST64_MIN
+# define INT_LEAST64_MAX   __INT_LEAST64_MAX
+# define UINT_LEAST64_MAX __UINT_LEAST64_MAX
+# define INT_FAST64_MIN    __INT_LEAST64_MIN
+# define INT_FAST64_MAX    __INT_LEAST64_MAX
+# define UINT_FAST64_MAX  __UINT_LEAST64_MAX
+
+/* FIXME: This is using the placeholder dates Clang produces for these macros
+   in C2x mode; switch to the correct values once they've been published. */
+#if __STDC_VERSION__ >= 202000L
+# define UINT_LEAST64_WIDTH __UINT_LEAST64_WIDTH
+# define INT_LEAST64_WIDTH  UINT_LEAST64_WIDTH
+# define UINT_FAST64_WIDTH  __UINT_LEAST64_WIDTH
+# define INT_FAST64_WIDTH   UINT_FAST64_WIDTH
+#endif /* __STDC_VERSION__ */
+#endif /* __INT_LEAST64_MIN */
+
+
+#ifdef __INT56_TYPE__
+# define INT56_MAX           INT56_C(36028797018963967)
+# define INT56_MIN         (-INT56_C(36028797018963967)-1)
+# define UINT56_MAX         UINT56_C(72057594037927935)
+# define INT_LEAST56_MIN     INT56_MIN
+# define INT_LEAST56_MAX     INT56_MAX
+# define UINT_LEAST56_MAX   UINT56_MAX
+# define INT_FAST56_MIN      INT56_MIN
+# define INT_FAST56_MAX      INT56_MAX
+# define UINT_FAST56_MAX    UINT56_MAX
+
+# define __INT_LEAST32_MIN   INT56_MIN
+# define __INT_LEAST32_MAX   INT56_MAX
+# define __UINT_LEAST32_MAX UINT56_MAX
+# define __INT_LEAST16_MIN   INT56_MIN
+# define __INT_LEAST16_MAX   INT56_MAX
+# define __UINT_LEAST16_MAX UINT56_MAX
+# define __INT_LEAST8_MIN    INT56_MIN
+# define __INT_LEAST8_MAX    INT56_MAX
+# define __UINT_LEAST8_MAX  UINT56_MAX
+
+/* FIXME: This is using the placeholder dates Clang produces for these macros
+   in C2x mode; switch to the correct values once they've been published. */
+#if __STDC_VERSION__ >= 202000L
+# define UINT56_WIDTH         56
+# define INT56_WIDTH          UINT56_WIDTH
+# define UINT_LEAST56_WIDTH   UINT56_WIDTH
+# define INT_LEAST56_WIDTH    UINT_LEAST56_WIDTH
+# define UINT_FAST56_WIDTH    UINT56_WIDTH
+# define INT_FAST56_WIDTH     UINT_FAST56_WIDTH
+# define __UINT_LEAST32_WIDTH UINT56_WIDTH
+# define __UINT_LEAST16_WIDTH UINT56_WIDTH
+# define __UINT_LEAST8_WIDTH  UINT56_WIDTH
+#endif /* __STDC_VERSION__ */
+#endif /* __INT56_TYPE__ */
+
+
+#ifdef __INT48_TYPE__
+# define INT48_MAX           INT48_C(140737488355327)
+# define INT48_MIN         (-INT48_C(140737488355327)-1)
+# define UINT48_MAX         UINT48_C(281474976710655)
+# define INT_LEAST48_MIN     INT48_MIN
+# define INT_LEAST48_MAX     INT48_MAX
+# define UINT_LEAST48_MAX   UINT48_MAX
+# define INT_FAST48_MIN      INT48_MIN
+# define INT_FAST48_MAX      INT48_MAX
+# define UINT_FAST48_MAX    UINT48_MAX
+
+# define __INT_LEAST32_MIN   INT48_MIN
+# define __INT_LEAST32_MAX   INT48_MAX
+# define __UINT_LEAST32_MAX UINT48_MAX
+# define __INT_LEAST16_MIN   INT48_MIN
+# define __INT_LEAST16_MAX   INT48_MAX
+# define __UINT_LEAST16_MAX UINT48_MAX
+# define __INT_LEAST8_MIN    INT48_MIN
+# define __INT_LEAST8_MAX    INT48_MAX
+# define __UINT_LEAST8_MAX  UINT48_MAX
+
+/* FIXME: This is using the placeholder dates Clang produces for these macros
+   in C2x mode; switch to the correct values once they've been published. */
+#if __STDC_VERSION__ >= 202000L
+#define UINT48_WIDTH         48
+#define INT48_WIDTH          UINT48_WIDTH
+#define UINT_LEAST48_WIDTH   UINT48_WIDTH
+#define INT_LEAST48_WIDTH    UINT_LEAST48_WIDTH
+#define UINT_FAST48_WIDTH    UINT48_WIDTH
+#define INT_FAST48_WIDTH     UINT_FAST48_WIDTH
+#define __UINT_LEAST32_WIDTH UINT48_WIDTH
+#define __UINT_LEAST16_WIDTH UINT48_WIDTH
+#define __UINT_LEAST8_WIDTH  UINT48_WIDTH
+#endif /* __STDC_VERSION__ */
+#endif /* __INT48_TYPE__ */
+
+
+#ifdef __INT40_TYPE__
+# define INT40_MAX           INT40_C(549755813887)
+# define INT40_MIN         (-INT40_C(549755813887)-1)
+# define UINT40_MAX         UINT40_C(1099511627775)
+# define INT_LEAST40_MIN     INT40_MIN
+# define INT_LEAST40_MAX     INT40_MAX
+# define UINT_LEAST40_MAX   UINT40_MAX
+# define INT_FAST40_MIN      INT40_MIN
+# define INT_FAST40_MAX      INT40_MAX
+# define UINT_FAST40_MAX    UINT40_MAX
+
+# define __INT_LEAST32_MIN   INT40_MIN
+# define __INT_LEAST32_MAX   INT40_MAX
+# define __UINT_LEAST32_MAX UINT40_MAX
+# define __INT_LEAST16_MIN   INT40_MIN
+# define __INT_LEAST16_MAX   INT40_MAX
+# define __UINT_LEAST16_MAX UINT40_MAX
+# define __INT_LEAST8_MIN    INT40_MIN
+# define __INT_LEAST8_MAX    INT40_MAX
+# define __UINT_LEAST8_MAX  UINT40_MAX
+
+/* FIXME: This is using the placeholder dates Clang produces for these macros
+   in C2x mode; switch to the correct values once they've been published. */
+#if __STDC_VERSION__ >= 202000L
+# define UINT40_WIDTH         40
+# define INT40_WIDTH          UINT40_WIDTH
+# define UINT_LEAST40_WIDTH   UINT40_WIDTH
+# define INT_LEAST40_WIDTH    UINT_LEAST40_WIDTH
+# define UINT_FAST40_WIDTH    UINT40_WIDTH
+# define INT_FAST40_WIDTH     UINT_FAST40_WIDTH
+# define __UINT_LEAST32_WIDTH UINT40_WIDTH
+# define __UINT_LEAST16_WIDTH UINT40_WIDTH
+# define __UINT_LEAST8_WIDTH  UINT40_WIDTH
+#endif /* __STDC_VERSION__ */
+#endif /* __INT40_TYPE__ */
+
+
+#ifdef __INT32_TYPE__
+# define INT32_MAX           INT32_C(2147483647)
+# define INT32_MIN         (-INT32_C(2147483647)-1)
+# define UINT32_MAX         UINT32_C(4294967295)
+
+# define __INT_LEAST32_MIN   INT32_MIN
+# define __INT_LEAST32_MAX   INT32_MAX
+# define __UINT_LEAST32_MAX UINT32_MAX
+# define __INT_LEAST16_MIN   INT32_MIN
+# define __INT_LEAST16_MAX   INT32_MAX
+# define __UINT_LEAST16_MAX UINT32_MAX
+# define __INT_LEAST8_MIN    INT32_MIN
+# define __INT_LEAST8_MAX    INT32_MAX
+# define __UINT_LEAST8_MAX  UINT32_MAX
+
+/* FIXME: This is using the placeholder dates Clang produces for these macros
+   in C2x mode; switch to the correct values once they've been published. */
+#if __STDC_VERSION__ >= 202000L
+# define UINT32_WIDTH         32
+# define INT32_WIDTH          UINT32_WIDTH
+# define __UINT_LEAST32_WIDTH UINT32_WIDTH
+# define __UINT_LEAST16_WIDTH UINT32_WIDTH
+# define __UINT_LEAST8_WIDTH  UINT32_WIDTH
+#endif /* __STDC_VERSION__ */
+#endif /* __INT32_TYPE__ */
+
+#ifdef __INT_LEAST32_MIN
+# define INT_LEAST32_MIN   __INT_LEAST32_MIN
+# define INT_LEAST32_MAX   __INT_LEAST32_MAX
+# define UINT_LEAST32_MAX __UINT_LEAST32_MAX
+# define INT_FAST32_MIN    __INT_LEAST32_MIN
+# define INT_FAST32_MAX    __INT_LEAST32_MAX
+# define UINT_FAST32_MAX  __UINT_LEAST32_MAX
+
+/* FIXME: This is using the placeholder dates Clang produces for these macros
+   in C2x mode; switch to the correct values once they've been published. */
+#if __STDC_VERSION__ >= 202000L
+# define UINT_LEAST32_WIDTH __UINT_LEAST32_WIDTH
+# define INT_LEAST32_WIDTH  UINT_LEAST32_WIDTH
+# define UINT_FAST32_WIDTH  __UINT_LEAST32_WIDTH
+# define INT_FAST32_WIDTH   UINT_FAST32_WIDTH
+#endif /* __STDC_VERSION__ */
+#endif /* __INT_LEAST32_MIN */
+
+
+#ifdef __INT24_TYPE__
+# define INT24_MAX           INT24_C(8388607)
+# define INT24_MIN         (-INT24_C(8388607)-1)
+# define UINT24_MAX         UINT24_C(16777215)
+# define INT_LEAST24_MIN     INT24_MIN
+# define INT_LEAST24_MAX     INT24_MAX
+# define UINT_LEAST24_MAX   UINT24_MAX
+# define INT_FAST24_MIN      INT24_MIN
+# define INT_FAST24_MAX      INT24_MAX
+# define UINT_FAST24_MAX    UINT24_MAX
+
+# define __INT_LEAST16_MIN   INT24_MIN
+# define __INT_LEAST16_MAX   INT24_MAX
+# define __UINT_LEAST16_MAX UINT24_MAX
+# define __INT_LEAST8_MIN    INT24_MIN
+# define __INT_LEAST8_MAX    INT24_MAX
+# define __UINT_LEAST8_MAX  UINT24_MAX
+
+/* FIXME: This is using the placeholder dates Clang produces for these macros
+   in C2x mode; switch to the correct values once they've been published. */
+#if __STDC_VERSION__ >= 202000L
+# define UINT24_WIDTH         24
+# define INT24_WIDTH          UINT24_WIDTH
+# define UINT_LEAST24_WIDTH   UINT24_WIDTH
+# define INT_LEAST24_WIDTH    UINT_LEAST24_WIDTH
+# define UINT_FAST24_WIDTH    UINT24_WIDTH
+# define INT_FAST24_WIDTH     UINT_FAST24_WIDTH
+# define __UINT_LEAST16_WIDTH UINT24_WIDTH
+# define __UINT_LEAST8_WIDTH  UINT24_WIDTH
+#endif /* __STDC_VERSION__ */
+#endif /* __INT24_TYPE__ */
+
+
+#ifdef __INT16_TYPE__
+#define INT16_MAX            INT16_C(32767)
+#define INT16_MIN          (-INT16_C(32767)-1)
+#define UINT16_MAX          UINT16_C(65535)
+
+# define __INT_LEAST16_MIN   INT16_MIN
+# define __INT_LEAST16_MAX   INT16_MAX
+# define __UINT_LEAST16_MAX UINT16_MAX
+# define __INT_LEAST8_MIN    INT16_MIN
+# define __INT_LEAST8_MAX    INT16_MAX
+# define __UINT_LEAST8_MAX  UINT16_MAX
+
+/* FIXME: This is using the placeholder dates Clang produces for these macros
+   in C2x mode; switch to the correct values once they've been published. */
+#if __STDC_VERSION__ >= 202000L
+# define UINT16_WIDTH         16
+# define INT16_WIDTH          UINT16_WIDTH
+# define __UINT_LEAST16_WIDTH UINT16_WIDTH
+# define __UINT_LEAST8_WIDTH  UINT16_WIDTH
+#endif /* __STDC_VERSION__ */
+#endif /* __INT16_TYPE__ */
+
+#ifdef __INT_LEAST16_MIN
+# define INT_LEAST16_MIN   __INT_LEAST16_MIN
+# define INT_LEAST16_MAX   __INT_LEAST16_MAX
+# define UINT_LEAST16_MAX __UINT_LEAST16_MAX
+# define INT_FAST16_MIN    __INT_LEAST16_MIN
+# define INT_FAST16_MAX    __INT_LEAST16_MAX
+# define UINT_FAST16_MAX  __UINT_LEAST16_MAX
+
+/* FIXME: This is using the placeholder dates Clang produces for these macros
+   in C2x mode; switch to the correct values once they've been published. */
+#if __STDC_VERSION__ >= 202000L
+# define UINT_LEAST16_WIDTH __UINT_LEAST16_WIDTH
+# define INT_LEAST16_WIDTH  UINT_LEAST16_WIDTH
+# define UINT_FAST16_WIDTH  __UINT_LEAST16_WIDTH
+# define INT_FAST16_WIDTH   UINT_FAST16_WIDTH
+#endif /* __STDC_VERSION__ */
+#endif /* __INT_LEAST16_MIN */
+
+
+#ifdef __INT8_TYPE__
+# define INT8_MAX            INT8_C(127)
+# define INT8_MIN          (-INT8_C(127)-1)
+# define UINT8_MAX          UINT8_C(255)
+
+# define __INT_LEAST8_MIN    INT8_MIN
+# define __INT_LEAST8_MAX    INT8_MAX
+# define __UINT_LEAST8_MAX  UINT8_MAX
+
+/* FIXME: This is using the placeholder dates Clang produces for these macros
+   in C2x mode; switch to the correct values once they've been published. */
+#if __STDC_VERSION__ >= 202000L
+# define UINT8_WIDTH         8
+# define INT8_WIDTH          UINT8_WIDTH
+# define __UINT_LEAST8_WIDTH UINT8_WIDTH
+#endif /* __STDC_VERSION__ */
+#endif /* __INT8_TYPE__ */
+
+#ifdef __INT_LEAST8_MIN
+# define INT_LEAST8_MIN   __INT_LEAST8_MIN
+# define INT_LEAST8_MAX   __INT_LEAST8_MAX
+# define UINT_LEAST8_MAX __UINT_LEAST8_MAX
+# define INT_FAST8_MIN    __INT_LEAST8_MIN
+# define INT_FAST8_MAX    __INT_LEAST8_MAX
+# define UINT_FAST8_MAX  __UINT_LEAST8_MAX
+
+/* FIXME: This is using the placeholder dates Clang produces for these macros
+   in C2x mode; switch to the correct values once they've been published. */
+#if __STDC_VERSION__ >= 202000L
+# define UINT_LEAST8_WIDTH __UINT_LEAST8_WIDTH
+# define INT_LEAST8_WIDTH  UINT_LEAST8_WIDTH
+# define UINT_FAST8_WIDTH  __UINT_LEAST8_WIDTH
+# define INT_FAST8_WIDTH   UINT_FAST8_WIDTH
+#endif /* __STDC_VERSION__ */
+#endif /* __INT_LEAST8_MIN */
+
+/* Some utility macros */
+#define  __INTN_MIN(n)  __stdint_join3( INT, n, _MIN)
+#define  __INTN_MAX(n)  __stdint_join3( INT, n, _MAX)
+#define __UINTN_MAX(n)  __stdint_join3(UINT, n, _MAX)
+#define  __INTN_C(n, v) __stdint_join3( INT, n, _C(v))
+#define __UINTN_C(n, v) __stdint_join3(UINT, n, _C(v))
+
+/* C99 7.18.2.4 Limits of integer types capable of holding object pointers. */
+/* C99 7.18.3 Limits of other integer types. */
+
+#define  INTPTR_MIN  (-__INTPTR_MAX__-1)
+#define  INTPTR_MAX    __INTPTR_MAX__
+#define UINTPTR_MAX   __UINTPTR_MAX__
+#define PTRDIFF_MIN (-__PTRDIFF_MAX__-1)
+#define PTRDIFF_MAX   __PTRDIFF_MAX__
+#define    SIZE_MAX      __SIZE_MAX__
+
+/* C2x 7.20.2.4 Width of integer types capable of holding object pointers. */
+/* FIXME: This is using the placeholder dates Clang produces for these macros
+   in C2x mode; switch to the correct values once they've been published. */
+#if __STDC_VERSION__ >= 202000L
+/* NB: The C standard requires that these be the same value, but the compiler
+   exposes separate internal width macros. */
+#define INTPTR_WIDTH  __INTPTR_WIDTH__
+#define UINTPTR_WIDTH __UINTPTR_WIDTH__
+#endif
+
+/* ISO9899:2011 7.20 (C11 Annex K): Define RSIZE_MAX if __STDC_WANT_LIB_EXT1__
+ * is enabled. */
+#if defined(__STDC_WANT_LIB_EXT1__) && __STDC_WANT_LIB_EXT1__ >= 1
+#define   RSIZE_MAX            (SIZE_MAX >> 1)
+#endif
+
+/* C99 7.18.2.5 Limits of greatest-width integer types. */
+#define  INTMAX_MIN (-__INTMAX_MAX__-1)
+#define  INTMAX_MAX   __INTMAX_MAX__
+#define UINTMAX_MAX  __UINTMAX_MAX__
+
+/* C2x 7.20.2.5 Width of greatest-width integer types. */
+/* FIXME: This is using the placeholder dates Clang produces for these macros
+   in C2x mode; switch to the correct values once they've been published. */
+#if __STDC_VERSION__ >= 202000L
+/* NB: The C standard requires that these be the same value, but the compiler
+   exposes separate internal width macros. */
+#define INTMAX_WIDTH __INTMAX_WIDTH__
+#define UINTMAX_WIDTH __UINTMAX_WIDTH__
+#endif
+
+/* C99 7.18.3 Limits of other integer types. */
+#define SIG_ATOMIC_MIN __INTN_MIN(__SIG_ATOMIC_WIDTH__)
+#define SIG_ATOMIC_MAX __INTN_MAX(__SIG_ATOMIC_WIDTH__)
+#ifdef __WINT_UNSIGNED__
+# define WINT_MIN       __UINTN_C(__WINT_WIDTH__, 0)
+# define WINT_MAX       __UINTN_MAX(__WINT_WIDTH__)
+#else
+# define WINT_MIN       __INTN_MIN(__WINT_WIDTH__)
+# define WINT_MAX       __INTN_MAX(__WINT_WIDTH__)
+#endif
+
+#ifndef WCHAR_MAX
+# define WCHAR_MAX __WCHAR_MAX__
+#endif
+#ifndef WCHAR_MIN
+# if __WCHAR_MAX__ == __INTN_MAX(__WCHAR_WIDTH__)
+#  define WCHAR_MIN __INTN_MIN(__WCHAR_WIDTH__)
+# else
+#  define WCHAR_MIN __UINTN_C(__WCHAR_WIDTH__, 0)
+# endif
+#endif
+
+/* 7.18.4.2 Macros for greatest-width integer constants. */
+#define  INTMAX_C(v) __int_c(v,  __INTMAX_C_SUFFIX__)
+#define UINTMAX_C(v) __int_c(v, __UINTMAX_C_SUFFIX__)
+
+/* C2x 7.20.3.x Width of other integer types. */
+/* FIXME: This is using the placeholder dates Clang produces for these macros
+   in C2x mode; switch to the correct values once they've been published. */
+#if __STDC_VERSION__ >= 202000L
+#define PTRDIFF_WIDTH    __PTRDIFF_WIDTH__
+#define SIG_ATOMIC_WIDTH __SIG_ATOMIC_WIDTH__
+#define SIZE_WIDTH       __SIZE_WIDTH__
+#define WCHAR_WIDTH      __WCHAR_WIDTH__
+#define WINT_WIDTH       __WINT_WIDTH__
+#endif
+
+#endif /* __STDC_HOSTED__ */
+#endif /* __CLANG_STDINT_H */
diff --git a/.ccls-cache/@@root@gpt-vue/@nix@store@rf7mgm3kn47ifbkyvvd87m8jkf4yc14p-clang-14.0.6-lib@lib@clang@14.0.6@include@stdint.h.blob b/.ccls-cache/@@root@gpt-vue/@nix@store@rf7mgm3kn47ifbkyvvd87m8jkf4yc14p-clang-14.0.6-lib@lib@clang@14.0.6@include@stdint.h.blob
new file mode 100644
index 0000000000000000000000000000000000000000..f8c6119049dabde2f19139fdff51b5b8031634ab
Binary files /dev/null and b/.ccls-cache/@@root@gpt-vue/@nix@store@rf7mgm3kn47ifbkyvvd87m8jkf4yc14p-clang-14.0.6-lib@lib@clang@14.0.6@include@stdint.h.blob differ
diff --git a/.ccls-cache/@root@gpt-vue/ddd.cpp b/.ccls-cache/@root@gpt-vue/ddd.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..95143ab633d5061b49cd33fd83bac0e59db5086e
--- /dev/null
+++ b/.ccls-cache/@root@gpt-vue/ddd.cpp
@@ -0,0 +1,172 @@
+#include<bits/stdc++.h>
+using namespace std;
+#define maxk_of_vector 1000000000
+#define my (*this)
+class big {
+		std::deque<unsigned long long>v;
+		/*00 00 22 55*/
+		/* 表示 2255*/
+		inline void ZERO_CLEAR__alg(deque<unsigned long long>v = v) {
+			/*去0*/
+			while (!v[0])v.pop_front();
+		}
+		inline void ZERO_ON_INT__alg(unsigned x, deque<unsigned long long>v = v) {
+			/*加0*/
+			while (v.size() < x)v.push_front(0);
+		}
+		inline void REMOVE_ARR__alg(deque<unsigned long long>v = v) {
+			/*反转*/
+			stack<int>x;
+			while (v.size())x.push(v.front());
+			while (x.size()) {
+				v.push_front(x.top());
+				x.pop();
+			}
+		}
+		inline void EQAUL_STRING__alg(string x) {
+			v.clear();
+			stack<char>c;
+			while (x.size()) {
+				c.push(x.back() ^ 48);
+				x.pop_back();
+			}
+			unsigned long long d = 0;
+			while (c.size()) {
+				if (d * 10 >= maxk_of_vector)v.push_back(d), d = 0;
+				d = d << 3 + d << 1 + c.top();
+			}
+		}
+		deque<unsigned long long> mul(deque<unsigned long long> &a, deque<unsigned long long> &b) {
+			deque<unsigned long long> ans(a.size() + b.size() + 1, 0); // 初始化结果数组
+			REMOVE_ARR__alg(a);
+			REMOVE_ARR__alg(b);
+			// 标准竖式乘法
+			for (int i = 0; i < a.size(); i++) {
+				unsigned long long carry = 0;
+				for (int j = 0; j < b.size(); j++) {
+					unsigned long long tmp = a[i]   b[j]   carry;
+					ans[i + j] += tmp;
+					carry = ans[i + j] / maxk_of_vector;
+					ans[i + j] %= maxk_of_vector;
+				}
+				if (carry) ans[i + b.size()] += carry;
+			}
+			REMOVE_ARR__alg(ans);
+			ZERO_CLEAR__alg(ans);
+			return ans;
+		}
+
+	public :
+		big(std::string x) {
+			EQAUL_STRING__alg(x);
+		}
+		big(unsigned long long x) {
+			v.clear();
+			v.push_back(x);
+		}
+		big(long long x) {
+			v.clear();
+			v.push_back(x);
+		}
+		big(unsigned long x) {
+			v.clear();
+			v.push_back(x);
+		}
+		big(short x) {
+			v.clear();
+			v.push_back(x);
+		}
+		big(unsigned short x) {
+			v.clear();
+			v.push_back(x);
+		}
+		big(char x) {
+			v.clear();
+			v.push_back(x);
+		}
+		big(unsigned char x) {
+			v.clear();
+			v.push_back(x);
+		}
+		big(big x) {
+			v = x.v;
+		}
+		~big() {
+			v.clear();
+		}
+		inline void operator = (unsigned long long x) {
+			v.clear();
+			v.push_back(x);
+		}
+		inline void operator = (long long x) {
+			v.clear();
+			v.push_back(x);
+		}
+		inline void operator = (unsigned long x) {
+			v.clear();
+			v.push_back(x);
+		}
+		inline void operator = (long x) {
+			v.clear();
+			v.push_back(x);
+		}
+		inline void operator = (unsigned short x) {
+			v.clear();
+			v.push_back(x);
+		}
+		inline void operator = (short x) {
+			v.clear();
+			v.push_back(x);
+		}
+		inline void operator = (big x) {
+			v = x.v;
+		}
+		inline void operator >>=(unsigned long long wei);
+		inline void operator <<=(unsigned long long wei);
+		inline big operator >>(unsigned long long wei);
+		inline big operator <<(unsigned long long wei);
+		inline big operator +(big x);
+		inline big operator -(big x);
+		inline big operator *(big x);
+		inline big operator /(big x);
+		inline big operator %(big x);
+		inline void operator +=(big x);
+		inline void operator -=(big x);
+		inline void operator *=(big x);
+		inline void operator /=(big x);
+		inline void operator %=(big x);
+		inline bool operator ==(big x) {
+			auto i = v.begin();
+			auto j = x.v.begin();
+			if (x.v.size() == v.size())while (i != v.end()) {
+					if (*i ^ *j)return false;
+					++i;
+					++j;
+				} else return false;
+			return true;
+		}
+		inline bool operator >=(big x) {
+			auto i = v.begin();
+			auto j = x.v.begin();
+			if (x.v.size() == v.size())while (i != v.end()) {
+					if (*i < *j)return false;
+					++i;
+					++j;
+				} else return v.size() >= x.v.size();
+			return true;
+
+		}
+		inline bool operator <=(big x) {
+			return !(my == x || my < x);
+		}
+		inline bool operator !=(big x) {
+			return !(my == x);
+		}
+		inline bool operator >(big x) {
+			return !(my <= x);
+		}
+		inline bool operator <(big x) {
+			return !(my >= x);
+		}
+};
+/*高精度*/
\ No newline at end of file
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